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FIELD OF THE INVENTION The present invention relates to systems and methods for monitoring service on communications networks, and particularly to systems and methods that cause minimal disruption to the communications network traffic by using passive monitoring of network traffic data packets. BACKGROUND OF THE INVENTION Internet Service Providers (ISPs) are highly desirous of providing Internet Protocol (IP) services, such as Voice over IP (VoIP) and IPTV, to their customers. In order to provide these high value services, the ISP networks need to provide a high Quality of Service (QoS) even as their networks become more complex. There is, therefore, an increased demand for sophisticated monitoring tools that allow the ISPs to rapidly identify degradation in their networks performance and quickly isolate the root cause of any problems. Such tools are critical for ensuring QoS guarantees and for reducing service downtimes through timely resolution of network problems. These monitoring tools typically monitor network traffic parameters such as delay and packet loss using either active or passive measurements. Active monitoring tools typically inject data packets into the network, or send data packets to applications, in order to obtain measurements of delays or losses. Passive monitoring devices, in contrast, snoop on existing data-packets as they traverse the network lines as normal network traffic. Passive monitoring has the advantage that it does not increase the traffic in the network. This can be critical when a network interface or link becomes congested. During such times, injecting additional traffic into the network for active measurements may exacerbate the very problem that is being diagnosed. The disadvantages of passive measurements, however, include having less control over the measurement process as only existing network traffic is used and that the amount of data that needs to be collected can be enormous. In order to control the costs of a passive monitoring infrastructure and the communication overhead between the monitors and the Network Operations Center (NOC), it is important to carefully select the locations at which passive monitoring probes are placed and the paths they are used to monitor. At the same time, it is important to ensure that the data collected by the monitoring probes is sufficient to provide a comprehensive and timely overview of the network's performance. In particular, it is important to provide enough passive monitoring locations that both a detection set of paths and a diagnostic set of paths can be monitored. A detection set of paths for passive monitoring of a communications network is the minimum set of paths that need to be monitored in order to detect that there is an anomaly somewhere in the network. A diagnostic set of paths is the minimum set of paths that need to be monitored in order to accurately locate and diagnose any anomaly that occurs anywhere in the network. SUMMARY OF THE INVENTION Briefly described, the invention provides a system and method for determining the optimal selection of paths for passively monitoring a communications network in order to detect and diagnose faults, and the optimal location for placing monitoring probes on the network to be able to monitor those paths. In a preferred embodiment of the invention, a diagnostic set of paths, or a close approximation to it, is determined by ensuring that, for all pairs of links in the network, the diagnostic set of paths contains at least one path having only one member of that pair of links. In a preferred embodiment of the invention, a detection set of paths that is a subset of the diagnostic set of paths is determined by ensuring that, for all the links in the communications network, there is at least one member of the detection subset of paths that contains that link. During normal operation of the network, only the detection subset of paths needs to be monitored, reducing the amount of data that needs to be collected and reported to a network central control. Once an anomaly is detected, the system may switch to monitoring the full diagnostic set of paths so that the anomaly can be fully diagnosed. The cost of deploying and operating the passive monitoring equipment is minimized by determining a probe location set of links in the communications network. This is the minimum set of links on which a probe needs to be placed in order to monitor the diagnostic set of paths. As the detection set of paths is a subset of the diagnostic set of paths, they will also be monitored by the probe place on the probe location set of links. These and other features of the invention will be more fully understood by references to the following drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic representation of a simple service provider network. FIG. 2A is a schematic representation of a first case of a node in a tree topology having an edge on which a probe can be placed to distinguish an undistinguished edge pair. FIG. 2B is a schematic representation of a second case of a node in a tree topology having an edge on which a probe can be placed to distinguish an undistinguished edge pair. FIG. 2C is a schematic representation of a third case of a node in a tree topology having an edge on which a probe can be placed to distinguish an undistinguished edge pair. FIG. 2D is a schematic representation of a fourth case of a node in a tree topology having an edge on which a probe can be placed to distinguish an undistinguished edge pair. DETAILED DESCRIPTION The present invention provides low-cost, low impact solutions for communications network monitoring infrastructures. In such systems, link level anomalies, such as excessive loss or delay of data packets traversing the network, are inferred from path-level passive measurements, i.e., network faults are monitored by observing the normal traffic flowing across the network. Such monitoring may be performed by placing and operating sophisticated monitoring tools at all nodes in the networks. This simple approach, however, is very costly. In order to reduce the cost, the method of this invention determines the optimum location of data monitoring probes on the network in order to minimize the number of data monitoring probes needed while ensuring that any anomaly that occurs anywhere in the network can be fully diagnosed. Communications networks may be modeled as directed graphs G (V, E) having vertices V and edges E. In such a model, a node v that is an element of V may represent a network router, a switch or a gateway, while the edges of the graph may represent communications links connecting the nodes. A directed communication from a node u to a node v may then be represented by <u, v> and the corresponding undirected physical link by {u, v}. As most modern networks are full-duplex networks, for every directed edge <u i , v i >εE, there is a directed edge <v i , u i >εE. Many Wide Area Networks (WAN) provided by, for instance, Service Providers have a general mesh topology with multiple paths between nodes in order to provide redundant paths. In enterprise environments, however, networks such as Ethernet frames are generally deployed using tree topologies, as they are simpler to implement and are more cost effective. All Internet Protocol (IP) packets in a typical Service Provider communications network originate and terminate at edge routers that interface with customer networks or other service provider networks, and are represented in a graph model of the network by edge nodes that are a subset of nodes from the set V. In an enterprise network, edge nodes may be client hosts or application servers such as web servers or mail servers. The IP traffic between a pair of nodes traverses the network through a sequence of nodes and links dictated by the network topology and routing protocol. For instance, in a Service Provider network, the communication path between a pair of edge nodes may either be a pre-configured Multiprotocol Label Switching (MPLS) or the shortest path between nodes computed used the Open Shortest Path First (OSPF). In a tree topology network the communication path between an edge node pair is unique and traces the edges of the spanning tree. In the graph model of the network, the set of paths between edge nodes are denoted by the set P that has members p, and where each p that is an element of P is a sequence of directed links that the path traverses. For simplicity, we assume that routing is symmetric, i.e., for every path p, there is a path {tilde over (p)} that is an element of P in the opposite direction. However, the schemes discussed in this paper are applicable even if the routing paths are asymmetric. Because passive monitoring relies on observing IP packets traversing the network to detect anomalies, paths with no traffic are not typically included in the set P. In most commercially available routers, data packets get delayed or lost primarily due to queuing at the transmitting or outbound interfaces. Thus, a loss or delay on a directed communication link <v i , v j > can usually be traced back to the outbound interface v i . Hence, a one-to-one correspondence between the link <v i , v j > and the outbound interface v i may be assumed for the purpose of anomaly detection. A passive monitoring infrastructure consists of a set of passive monitoring devices placed at various points in the network where they passively analyze the traffic that passes by. Various devices are available to do the observing. Most commercial routers or switches, for instance, support port mirroring in which each incoming and outgoing packet from one port of the network switch can be copied to another port where the copy of the packet can be studied. There are also hardware devices known as network taps that hook directly into a network cable and send a copy of the traffic that passes through it to one or more other networked devices. A network tap placed on a link between two nodes can measure both forward and reverse traffic on the link and is effectively measuring the incoming and outgoing traffic on the ports at the endpoints of the link. The measurements made by port mirroring and network taps are, therefore, logically equivalent. Passive monitoring devices may include the port mirrors or network taps and any associated local processing device for storing and/or forwarding the information gathered. FIG. 1 is a schematic representation of a simple service provider network 10 , having four passive monitoring devices 12 , five links 14 and twelve possible paths 16 that can be passively monitored if they contain data. For simplicity, FIG. 1 shows only two of the paths 16 . The paths 16 may be represented as <a, v 1 , v 2 , b>, <a, v 1 , v 2 , c>. <a, v 1 , v 2 , d>, <b, v 2 , v 1 , c>, <b, v 2 , d>, <a, v 1 , c> and their inverses. In providing a passive monitoring infrastructure for the service provider network 10 , an objective is to minimize costs by deploying as few passive monitoring devices 12 as possible that will allow the accurate detection and diagnosis of all single link anomalies. In doing this placement, the assumption is that a path reports an anomaly if and only if it contains a link with an anomaly, and that each network anomaly is caused by a single link. The anomalies to be monitored include data packet losses and data packet delays. Excessive data packet losses may be detected by, for instance, using passive monitoring devices tap 1 and tap 2 to monitor the data packets traversing the network via the path p 1 represented by <a, v1, v2, b>. At regular intervals, e.g., 1, 10 or 30 seconds, both tap 1 and tap 2 send to a central Network Operations Center (NOC) the number of packets seen on path p 1 in the most recent time interval. If the difference between the packet counts by tap 1 and tap 2 exceeds a certain pre-specified threshold even after accounting for packets still in transit along the path, then the NOC may conclude that an excessive amount of packets are being lost along some links of the path p. Alternately, the passive monitoring devices tap 1 and tap 2 may send samples of the observed packets on path p 1 to the NOC, and an inference of excessive losses on path p can be made if there is a large discrepancy in the samples from the two passive monitoring devices (also known as probes). Similarly, by associating timestamps with the data packets, it is possible to detect excessive delays along path p by keeping track at the NOC of the difference between packet timestamps averaged over an interval or for sample packets. If an anomaly is reported on path p 1 , additional paths may be monitored in order to determine in which of the links <a, v1>,<v1, v2> or <v2, b> the anomaly has occurred. Assuming that a path reports an anomaly if and only if it contains a link with an anomaly and that the network anomaly is caused by a single link (representing an interface), it is possible to show that a set of monitored paths Q is sufficient to diagnose which is the anomalous link if, for every pair of links (e1, e2) in the set E of the graph G(V, E) representing the network, there is at least one monitored path in Q that contains exactly one of the two links. Probe Placement The probe placement problem solved by the method of this invention may be stated formally along the following lines. Given a directed graph, G=(V, E) and a set of paths P between edge nodes in V, let L represent the set of directed edge-pairs which cannot be distinguished by paths in P. Select the smallest number of undirected edges F on which to place probes so that every link pair in L is distinguished by some edge in F. If each potential probe location edge F is represented by the subset LF of link pairs L that a probe on F will distinguish, then the problem becomes selecting the smallest number of subsets LF that contain all of L, i.e., the union of all selected subsets LF is L. The probe placement problem is, therefore, reduced to a classic Set Cover optimization problem. Given a universe U and a collection of subsets S of U, a set cover is the sub-collection C of the subsets S whose union is U, i.e., a set cover is the sub-collection C that contains all the elements of U. Set Cover optimization comprises finding the smallest sub-collection C that is a set cover. It is well-known that the Set Cover problem is Non-deterministic Polynomial-time (NP) complete, and the optimization version of set cover is NP hard. It is also well-known that that the greedy algorithm is the best-possible polynomial time approximation algorithm for set cover under plausible complexity assumptions. The greedy algorithm for set cover chooses sets according to one rule: at each stage, choose the set which contains the largest number of uncovered elements. For a mesh topology network, the minimum number of probe locations needed for passive monitoring of the network can, therefore, be found by the following greedy algorithm for optimal probe placement: 1. Represent the network as a directed graph G=(V, E); 2. Determine P, the set of paths between edge nodes in V; 3. Determine L, the set of directed edge-pairs which cannot be distinguished by paths in P; 4. Determine F, the set of undirected edges available to have probes placed on them; 5. Represent each member of F by the subset LF of link pairs L that a probe on F will distinguish; 6. Select F corresponding to the largest subset L F ; and 7. Repeat 2 to 6 with P now including all new paths made possible by selecting F until L=0. For tree topology networks, an alternate algorithm can be used to find near optimal probe location. This more restricted problem can be shown to correspond to finding an optimal vertex cover. As vertex cover is known to be NP complete and, therefore, there is unlikely to be an efficient algorithm to solve it. A lazy placement algorithm embodiment of this invention can, however, be shown to be a 3-approximation of the optimal solution, i.e., if the algorithm of this invention produces placement of F probes, and the optimal solution is O probes, |F|≦3|O|. The lazy placement algorithm proceeds bottom up in a tree topology and uses a lazy probe placement strategy, i.e., a link is only selected for placement if it distinguishes a link that cannot be distinguished further up in the tree. TABLE 1 Lazy placement algorithm for solving the probe placement problem in a tree topology network Initially set the solution F(O) = { }, and the set of undistinguished link pairs L(0) = L; for i = 1 to |V| do  Given the set L(i − 1), make local decision for child  edges of n i ;  Add the selected edges to the solution F(i);  Remove the link pairs distinguished by F(i) from  L(i − 1) to get L(i); end In a preferred embodiment of the invention, the algorithm proceeds as follows: Chose a root node; Then proceed bottom up the tree, i.e., before processing any node, process all the node's children; For each node, decide whether to select the child nodes for probe placement, where a child node for node n denotes the edges connecting a node n to its direct children, child(n)={c 1 , c 2 , . . . c m ). A probe on any edge in a tree topology can distinguish a directed link pair if and only if the two links are on either side of it. A child edge {n, c j } of n, therefore, can only distinguish an undistinguished link pair if one of the two directed links in the pair is in the subtree rooted at c j or on {n, c j } and the other is outside the subtree or on {n, c j }. Furthermore, such a link pair is characterized as being a “ripe link”, i.e., a link pair that cannot be distinguished further up the tree if it satisfies one of the four cases illustrated in FIG. 2A , 2 B, 2 C or 2 D. FIG. 2A shows the case in which one, upwardly directed link e 2 is either in the subtree rooted at the child node c j or is <c j n,> and the other upwardly directed link e 1 is on the edge connecting n to its parent. FIG. 2B shows the case in which one, downwardly directed link e 2 is in the subtree rooted at the child node c j o and the other downwardly directed link e 1 is on the link <n, c j >. FIG. 2C shows the case in which one, upwardly directed link e 2 is either in the subtree rooted at the child node c j or is <c j n,> and the other downwardly directed link e 1 is on the edge connecting n to another child. FIG. 2D shows the case in which one, upwardly directed link e 1 is either in the subtree rooted at the child node c j or is <c j n,> and the other downwardly directed link e 2 is in a subtree of another child of n In the cases represented by FIGS. 2A , 2 B and 2 C, the probe is placed on the child edge {n, c j }. In the case represented by 2 D the probe may be placed on either of the two child edges involved, {n, c j } or {n, c k }. The lazy placement algorithm of table 1 ensures that at each step all the ripe pairs in L are distinguished. Each time an edge is added to F, the probe placement solution set, all the link pairs distinguished by it are removed from L. If, from the remaining child edges of n, the subset of child edges which distinguish one or more undistinguished link pairs from L under the case of FIG. 2D can be represented by a set C and the set of those case of FIG. 2D link pairs from L can be represented by a set S. As each pair in S can be distinguished by two child edges, {n, c j } or {n, c k }, the problem of selecting the minimum subset of C such that all the link pairs in S are distinguished can be reduced to the Set Cover problem instance (S, C) with each element belonging to exactly two sets, which is the definition of a Vertex Cover. A Vertex Cover of an undirected graph G=(V,E) is a subset V′ of the vertices of the graph which contains at least one of the two endpoints of each edge. The well known 2-approximation algorithm for Vertex Cover can be used to find a subset of C which distinguishes all the link pairs in S and add the subset to the solution F. The factor-2 approximation algorithm is to repeatedly take both endpoints of an edge into the vertex cover, then remove them from the graph. No better constant-factor approximation is known. Path Selection for Anomaly Detection The problem of path detection for anomaly detection can be stated formally as follows. Given a directed graph G=(V, E) and a set of paths P′ that can be monitored by passive probes, select the minimum subset of paths Q det such that every directed link in E belongs to at least one path in Q det . This may be termed the path cover problem. In a mesh topology, a the path cover problem can be shown to be equivalent to the set cover problem. The greedy algorithm for set cover can, therefore, be used as a logarithmic approximation algorithm for selecting a minimum subset of paths to cover all the directed links. As described above, the greedy algorithm chooses sets according to one rule: at each stage, choose the set which contains the largest number of uncovered elements. In a tree-topology network, a 2-approximation to the optimal path cover in the network is possible. The method consists of selecting a root, then, from each leaf node of the tree, selecting the path that comes closest to the root. Both directions of the path are then included in the solution set. If there are n leaf node vertices, clearly at least n paths are needed to completely cover all the directed links in the network. This is because each path can cover at most two directed links from those incident on the leaf nodes: the link directed from the leaf node at which the path starts to an inner node and the link directed from an inner node to the leaf node at which the path terminates. Thus at least n paths are required to cover the 2n directed links on n leaf nodes. Our solution has 2n paths and so is at least a 2-approximation. If a link is covered by a path, then from one of the leaf nodes serving as endpoints of the path, the link will be on the path from the leaf node to the root, so the link will be covered by the closest path to the root from that leaf node. Therefore, all the links in the tree will be covered by the selected paths. By including both the forward and reverse paths in the solution set, all the directed links will be covered. Path Selection for Anomaly Diagnosis A set of paths Q is sufficient to diagnose an anomalous link, if, for every pair of links (e 1 , e 2 ) in E, there is at least one path in Q that contains exactly one of the two links. Such a path is said to distinguish between the links e 1 and e 2 . Given a network defined as a directed graph G=(V, E) and a set of paths P′ that can be monitored by passive probes, path selection for anomaly diagnosis requires finding the minimum set of paths Q that distinguish all link pairs in E and is a subset of P′. For mesh graph topologies, the anomaly diagnosis problem can be reduced to a set cover problem by reducing each link pair to an element and each path to the set of link pairs it distinguishes. As noted above, a path distinguishes all the links it contains from all the links it does not contain. In this reduction, p={e 1 , e 2 }εP, where e 1 , e 2 εE is reduced to the set {(e 1 , e j )|e j εE, e j {tilde over (ε)}p}∪{(e 2 , e j )|e j εE, e j {tilde over (ε)}p}. The greedy algorithm for set cover can then be used to give a logarithmic factor approximation algorithm to compute a subcollection of paths that distinguishes all the link pairs. In the greedy algorithm, sets are chosen according to one rule: at each stage, choose the set which contains the largest number of uncovered elements. For tree topologies, there is a 12-approximation algorithm for solving the anomaly diagnosis problem. Given a tree T having n vertices, with the edges denoted by E and where P is the required set of paths, the algorithm proceeds by first obtaining a solution in each undirected edge of the tree. Once a diagnosis path set is obtained for an undirected tree network, each path in the solution can be replaced by the corresponding directed paths in both directions in order to differentiate any two directed links. A diagnosis path set should be at least a constant fraction of the number of vertices n in the tree network. Such a diagnosis path set whose size is a constant times n may be chosen as follows: Let the optimal diagnosis path set be D o , a solution be DC and an undirected solution path set D. First, find the undirected path cover using the 2-approximation algorithm detailed above. In this method a root is selected, then, from each leaf node of the tree, selecting the path that comes closest to the root. For the undirected case, any path cover size is at least n 1 /2, and the 2-approximation algorithm gives a path cover size of n 1 where n 1 are the leaf nodes of the tree. Call this undirected path cover set C and make D=C. Second, for each edge e={u e , v e }, fix a path P e in the path cover that covers this edge. Also, denote by s e and t e the end points Of P e and let s e be the end closer to u e . Thirdly, each edge e={u, v} divides the path P e into at most three segments (s e , u e ), (u e , v e ) and (v e , t e ). Among all the paths that pass through e and deviate from P e in the segment (s e , u e ), choose the one that deviates at a vertex closest to u e . Call this path P s,e . Similarly, choose P t,e . If no such path exists, or u e or v e are the endpoints, do not choose the corresponding path. Add the chosen paths to D. The diagnostic path solution set DC can be shown to be a 12-approximation of the optimum solution D o . Although the invention has been described in language specific to structural features and/or methodological acts, it is to be understood that the invention defined in the appended claims is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as exemplary forms of implementing the claimed invention. Modifications may readily be devised by those ordinarily skilled in the art without departing from the spirit or scope of the present invention.

A system and method for determining optimal selection of paths for passively monitoring a communications network. A diagnostic set of paths is determined by ensuring that, for all pairs of links in the network, the set contains one path having only one member of that pair. A detection subset of paths is determined by ensuring that, for all the links in the network, one member of the subset contains that link. Selecting a minimum detection and diagnostic set of paths minimizes the communication overhead imposed by monitoring. During normal operation, only the detection subset need be monitored. Once an anomaly is detected, the system may switch to monitoring the full diagnostic set. The cost of deploying and operating the passive monitoring equipment is minimized by determining the minimum set of links on which a probe needs to be placed in order to monitor the diagnostic set of paths.

BACKGROUND INFORMATION [0001] 1. Field [0002] Embodiments of the disclosure relate generally to the field of packaging for pastry and baked goods and more particularly to a multidiametric case for a cupcake or similar good, the case having a relieved upper portion for clearance of frosting or topping, an aperture in the bottom allowing easy removal of the cupcake from the package and retaining elements within the case for closely contacting the cupcake for retention in the package until removal. [0003] 2. Background [0004] Cupcakes and similar baked goods and pastries are typically packaged in boxes containing multiple units. Baked goods such as cupcakes are quite fragile in nature and such packaging does not provide satisfactory protection for the baked goods, allowing individual cupcakes to move within the box creating distortion or damage to the soft cake and frosting. Retaining elements within the multiunit box have been previously employed as disclosed in U.S. Pat. No. 6,003,671 issued to McDonnough et al on Dec. 21, 1999. However extracting individual cupcakes is typically not easy or convenient and such packaging is not readily economically adaptable for individual cupcakes. [0005] Individual packaging has been provided in the form of small boxes or paper wrapping which suffer many of the same issues as multiunit packaging. Certain single item packages such as that disclosed in US patent publication 2004/0251162 to McGinnis et al published on Dec. 16, 2004 have been provided, however, such packaging is overly complex and expensive to be cost effective for high quantity production and sale of baked goods. [0006] It is therefore desirable to provide a cost effective packaging system for individual cupcakes or similar baked goods. It is additionally desirable that such a packaging system would allow easy removal of the cupcake without damage while retaining the cupcake safely within the package until removal is desired. SUMMARY [0007] Exemplary embodiments provide cupcake package employing a base element having a primary diameter for receiving a cupcake body and a relieving cylinder having a second diameter extending from the base element for clearance of a top contour of the cupcake. A bottom surface closes the base element and includes an aperture centrally located therein sized to accept insertion of a finger for removal of the cupcake. A cylindrical lid is closely received over the relieving cylinder to close the package. In one exemplary embodiment the base element is frustoconical. [0008] In certain implementations, the base element further incorporates a restraint system for the cupcake. A first restraint system includes two sets of opposing apertures in the base element vertically displaced from and perpendicular to each other. A first dowel is received through the first set of apertures and extending through a cupcake body carried in the base element and a second dowel is received through the second set of apertures and extending through the cupcake body. [0009] A second restraint system incorporates multiple pyramidal protuberances extending from an inner surface of the base element oriented with an extended point downward toward the bottom to engage the body of the cupcake. [0010] A third restraint system uses one or more circular ridges extruded from an inner surface of the base element to engage the body of the cupcake. [0011] The features, functions, and advantages that have been discussed can be achieved independently in various embodiments of the present invention or may be combined in yet other embodiments further details of which can be seen with reference to the following description and drawings BRIEF DESCRIPTION OF THE DRAWINGS [0012] FIG. 1A is a bottom angle isometric view of a general embodiment of the cupcake package of the present invention; [0013] FIG. 1B is a side view of the embodiment of FIG. 1A ; [0014] FIG. 1C is a bottom view of the embodiment of FIG. 1A ; [0015] FIG. 1D is a top angle isometric view of the embodiment of FIG. 1A with the closure lid removed; [0016] FIG. 1E is a side section view of the embodiment of FIG. 1A with a cupcake inserted in the case; [0017] FIG. 1F is the side section view of the case with the cupcake being removed; [0018] FIG. 2A is a bottom angle isometric view of an embodiment of the cupcake package with a first restraint structure; [0019] FIG. 2B is a top angle isometric view of the embodiment of FIG. 2A ; [0020] FIG. 2C is a bottom view of the embodiment of FIG. 2A ; [0021] FIG. 2D is a top view of the embodiment of FIG. 2A showing interior details of the embodiment; [0022] FIG. 2E is a side section view of the embodiment of FIG. 2A ; [0023] FIG. 3A is a top isometric view of an embodiment of the cupcake package with a second restraint structure; [0024] FIG. 3B is a top view of the embodiment of FIG. 3A ; [0025] FIG. 3C is a side section view of the embodiment of FIG. 3A ; [0026] FIG. 4A is a top isometric view of an embodiment of the cupcake package with a third restraint structure; and, [0027] FIG. 4B is a side section view of the embodiment of FIG. 4A . DETAILED DESCRIPTION [0028] The embodiments described herein disclose a cupcake package having a multidiametric case with multiple cylindrical elements or a combination of cylinders and conical frustrums to receive the cupcake and having a bottom with an aperture for urging the cupcake from the case with a consumer's finger, a lid for closing the case, and various restraint elements within the case to maintain the cupcake in the case until removed. [0029] As shown in FIG. 1A-1E for an exemplary embodiment, a frustoconical base element 10 of the case with a first primary diameter 11 receives the body of the cupcake (as best seen in FIG. 1E ). The shape of the base element may be a conical frustrum as shown for use with a conventional cupcake or various depths and diameters of cylindrical elements or other rotated geometric shapes defined to closely receive the baked good. The inner surface 12 of the base element frictionally engages the sides of the cupcake to assist in retaining the cupcake in the package and prevent unwanted motion in the package during handling or transport. A cylindrical top element 14 expands from the base element 10 to a second diameter 15 to allow volumetric relief within the package for frosting or top contouring of the cupcake or other baked good to be contained in the case. Further, the larger diameter of the top element simplifies the insertion of the cupcake or baked good into the case. [0030] A lid 16 having an inner diameter sized to be closely received over the cylindrical top element 14 provides a closure for the case to protect the cupcake or baked good after insertion into the case. For the embodiment shown a filleted external surface of the lid allows for easy grasping by the consumer for removal. In alternative embodiments, a smooth cylindrical external surface or a textured surface may be employed. [0031] A bottom surface 18 of the base element 10 incorporates an aperture 20 which is sized to accommodate insertion of a fingertip. As best seen in FIG. 1F , after removing the lid, inserting a fingertip through aperture 20 and pressing upward against the bottom 22 of the cupcake urges the cupcake body 24 from the case allowing the consumer to easily remove the cupcake for consumption. [0032] For the exemplary embodiments, injection molded polystyrene or similar material may be employed for the case and lid providing a very low cost, mass producible product. Alternative paper, cardboard or plastic materials may be employed in alternative embodiments using standard fabrication techniques known to those skilled in the art. [0033] To further restrain the cupcake in the case, a restraint system is employed. As shown in FIGS. 2A-2E , a first exemplary restraint system for the embodiment shown incorporates apertures 30 in the base element through which wooden or plastic toothpicks or dowels 32 are inserted, piercing the body of the cupcake. The dowel ends extend through the apertures 30 on each side of the base element thereby restraining the cupcake within the case. For the embodiment shown, two perpendicular vertically offset sets of apertures and dowels are employed. In alternative embodiments, a single aperture set and dowel may be employed or additional sets for increased security. For removal of the cupcake, the dowels are extracted from the case and the cupcake is removed by inserting a finger into the aperture 20 in the bottom 18 to urge the cupcake out of the case. [0034] A second exemplary restraint system is shown in FIGS. 3A-3C which employs pyramidal protuberances 34 extending from the inner surface 12 of the base element 10 . Orientation of the protuberances with point 36 extending downwardly toward the bottom 18 of the base element engages and restrains the body of the cupcake when the cupcake is placed into the case and urged toward the bottom. For the embodiment shown, four pyramidal protuberances 34 are shown. In alternative embodiments one or more protuberances may be employed as required to firmly secure the cupcake or other backed good in the case. For removal of the cupcake, inserting a finger into the aperture 20 in the bottom 18 and urging the cupcake upwards with sufficient force overcomes the friction created by the indentation of the pyramidal protuberances in the body of the cupcake allowing it to be removed from the case. [0035] Ridges 38 extruded from the inner surface 12 of the base element 10 provide a third exemplary retention system for the embodiments disclosed as shown in FIGS. 4A and 4B . For the embodiment shown, the ridges extend around an entire circumference of the inner surface and two ridges are employed. In alternative embodiments ridges extending over a portion of the circumference or a single or additional multiples of ridges are employed. A substantially circular cross section of the ridges is employed which provides sufficient resistance against the body of the cupcake to retain the cupcake in the case. However, alternative cross sections such as triangular or rectangular may be employed in alternative embodiments. As with the pyramidal protrusions, removal of the cupcake is accomplished by inserting a finger into the aperture 20 in the bottom 18 and urging the cupcake upwards with sufficient force overcomes the friction created by the indentation of the circular ridges in the body of the cupcake allowing it to be removed from the case. [0036] Having now described various embodiments of the invention in detail as required by the patent statutes, those skilled in the art will recognize modifications and substitutions to the specific embodiments disclosed herein. Such modifications are within the scope and intent of the present invention as defined in the following claims.

A cupcake package includes a base element having a primary diameter for receiving a cupcake body and a relieving cylinder having a second diameter extending from the base element for clearance of a top contour of the cupcake. A bottom surface closes the base element and includes an aperture centrally located therein sized to accept insertion of a finger for removal of the cupcake. A cylindrical lid is closely received over the relieving cylinder to close the package.

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to magnetic separation generally and, more particularly, but not by way of limitation, to a novel apparatus that permits the automatic separation of magnetic components in a laboratory microplate. [0003] 2. Background Art [0004] In the field of biology, there are requirements for the separation of one constituent from another. Some of the more commonly used methods are centrifugation, filtration, and magnetic separation. Centrifugation uses centrifugal force to provide separation by elements of mass. Filtration provides separation by size. Magnetic separation uses a magnetic field to attract and hold magnetic particles, or magnetic beads, so that the supernate in which the suspended are disposed can be removed. [0005] Magnetic beads are particularly useful in immunoassays. Constituents of interest may be coated on the surface of paramagnetic particles. Using an applied magnetic field, the beads may be congregated and retained from the surrounding liquid reagents of reactants. U.S. Pat. No. 5,779,907, issued Jul. 14, 1998, to Yu, and titled MAGENTIC MICROPLATE SEPARATOR, describes a means and method of providing magnetic separation. As described in the patent, a laboratory tray, or microplate, containing a number of vertical wells is placed on a fixture having a number of upstanding cylindrical magnets. The arrangement of wells and magnets is such that each magnet is disposed adjacent four of the wells. Thus, a 96-well plate requires a fixture that has 24 magnets. The magnetic components in the wells are attracted to the sides of the wells adjacent the magnets. The supernate in the wells can then be removed. The apparatus described by Yu is entirely satisfactory for manual use; however, it does not meet the need of processing the large numbers of samples that are required in the fields of genomic and drug discovery research. Automation is required for processing large numbers of samples. [0006] Conventionally, in automated magnetic separation systems, a robotic arm moves the laboratory trays over a fixed plate of magnets. While this provides an improvement over the manual method, it requires an additional positioning of the laboratory tray. [0007] Accordingly, it is a principal object of the present invention to provide an apparatus for magnetic separation that does not require a separate step of positioning of the laboratory plate. [0008] It is a further object of the invention to provide such an apparatus that can be remotely and automatically controlled. [0009] It is an additional object of the invention to provide such an apparatus that can be economically constructed using conventional techniques. [0010] It is another object of the invention to provide such an apparatus that can be part of a robotic liquid handling system. [0011] Other objects of the present invention, as well as particular features, elements, and advantages thereof, will be elucidated in, or be apparent from, the following description and the accompanying drawing figures. SUMMARY OF THE INVENTION [0012] The present invention achieves the above objects, among others, by providing, in a preferred embodiment, an apparatus for automated magnetic separation of materials in laboratory trays, comprising: a frame upon an upper surface of which a multiwell laboratory tray may be placed, a base plate on which is mounted a plurality of upstanding magnets disposed below said upper surface; and means to raise said base plate such as to insert said upstanding magnets into interwell spaces in said laboratory tray. BRIEF DESCRIPTION OF THE DRAWING [0013] Understanding of the present invention and the various aspects thereof will be facilitated by reference to the accompanying drawing figures, provided for purposes of illustration only and not intended to define the scope of the invention, on which: [0014] [0014]FIG. 1 is an isometric view of a microplate positioned over a plate of magnets. [0015] [0015]FIG. 2 is a side elevational view of the invention, partially in cross-section, with a plate of magnets in lowered position. [0016] [0016]FIG. 3 is a side elevational view of the invention, partially in cross-section, with a plate of magnets in raised position, such that the magnets are disposed between the wells of the microplate. [0017] [0017]FIG. 4 is a block/schematic view of a control system for the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0018] Reference should now be made to the drawing figures on which similar or identical elements are given consistent identifying numerals throughout the various figures thereof, and on which parenthetical references to figure numbers direct the reader to the view(s) on which the element(s) being described is (are) best seen, although the element(s) may be seen on other figures also. [0019] [0019]FIG. 1 illustrates a microplate 10 having a plurality of vertical wells, as at 12 , positioned over a plate of magnets 14 having a plurality of upstanding cylindrical magnets, as at 16 Wells 12 and magnets 16 are arranged such that, when microplate 10 and plate of magnets 14 are brought together, each magnet 16 will be moved into one of a plurality of positions, as at 20 , in the microplate and, so disposed, each magnet will be adjacent four of the wells. Microplate 10 is shown as having 96 wells arranged in a 8×12 matrix and plate of magnets 14 consequently has 24 magnets. It will be understood, however, that the invention may be applied as well to other numbers of microplate wells. In this position, the magnetic flux surrounding each magnet 16 encompasses four adjacent wells 12 . Paramagnetic particles in wells 12 will be attracted by this field and will be drawn to the sidewalls of the wells, adjacent to each magnet 16 . The supernate can then be withdrawn from the wells by, for example, aspiration. [0020] [0020]FIG. 2 illustrates an apparatus, constructed according to the present invention, and generally indicated by the reference numeral 50 . Apparatus 50 includes a frame 60 having a horizontal bottom plate 62 and a horizontal top plate 64 , the latter having a plurality of vertical holes defined therethrough, as at 66 . A plurality of upstanding vertical magnets, as at 70 , is fixedly attached to a horizontal, non-magnetic base plate 72 that includes four bearings 74 (only two shown) journaled on four vertical guide pins 76 (only two shown) extending between and fixedly attached to bottom plate 62 and top plate 64 . Thus arranged, base plate 72 may move vertically upwardly and downwardly in frame 60 . Base plate 72 is held in its down position against four stops 80 (only two shown) fixedly attached to bottom plate 62 by the action of four compression springs 82 (only two shown) disposed around guide pins 76 and compressed between the lower surface of top plate 64 and the upper surface of the base plate. [0021] A flexible bladder 90 disposed between the upper surface of bottom plate 62 and the lower surface of base plate 72 provides the motive force to raise the base plate. Bladder 90 may be simply constructed from a bicycle inner tube that is clamped between two clamps 100 fixedly attached to bottom plate 62 . One of clamps 100 is fitted with an air line connection (not shown) to permit flow of pressurized air to the closed interior of bladder 90 . [0022] As shown on FIG. 2, a microplate 110 having a plurality of vertical wells 1 12 has been placed on the upper surface of top plate 64 . Since base plate 72 is shown in its lowered position, magnets 70 are spaced below wells 112 . [0023] [0023]FIG. 3 illustrates the elements of apparatus 50 described above (FIG. 2), with pressurized air having been introduced into bladder 90 . The inflation of bladder 90 causes base plate 72 to rise, that motion causing magnets 70 to extend through openings 66 and between wells 112 . As will be understood from inspection of FIG. 1 and the accompanying text, each of magnets 70 will be inserted adjacent four of wells 112 in microplate 110 . Supernate can now be removed from wells 112 by any suitable means such as by aspiration of the supernate.. Expansion of bladder 90 is limited by the confines of frame 60 . The upward force provided by the inflation of bladder 90 exceeds the downward forces being applied by compression springs 82 , permitted the elevation of base plate 72 . Venting of compressed air from bladder 90 will cause the bladder to collapse and base plate 72 to return to its lowered position (FIG. 2) by means of the downward force provided by compression springs 82 . [0024] [0024]FIG. 4 illustrates a control system that may be used with apparatus 50 , the control system being generally indicated by the reference numeral 200 . Control system 200 includes a system controller 210 that may be a section of a controller used to control other features of a complete analysis system. Controller 210 is operatively connected to control a three-way solenoid valve 220 that permits compressed air from a compressed air source 222 to inflate bladder 90 to raise base plate 72 to its elevated position (FIG. 3) or to vent air from the bladder to cause the base plate to move to its lowered position (FIG. 2). [0025] The present invention provides a simple and effective means of moving magnets into the interwell spacing of a microplate by remote means. In the case described, low air pressure applied to a bladder, lifts the magnets. [0026] Using a remotely controlled method of actuating the magnets into the interwell spacing permits the inclusion of the device into a liquid handling robot. This permits completed automation of the entire liquid handling function. The first step in bioassays, using magnetic beads or particles, is to react the coated elements on the beads with other liquid reagents. This requires the beads to be in suspension to provide full exposure of the reacting elements. Normally, some means of agitation is incorporated, such as shaking or multiple aspirations dispensings. [0027] Following the reaction step is the separation step. A magnetic field is applied, drawing the magnetic beads to the sidewalls of the containing well. This separates the beads from the liquid in the well, permitting the liquid to be withdrawn by an automated pipettor. This process may be repeated multiple times, depending on the assay protocol and how many different reagent reactions are required. [0028] By the use of a remote means of controlling the insertion of the magnets, the action may by easily accommodated in liquid handling robotics control systems, such as supplied by Tomtec, Inc., of Hamden, Conn. An actuating signal is generated in the control system software This signal controls an electrically operated solenoid valve that applies controlled air pressure to the device operating the magnets. By being small and compact, the magnetic device can be located directly on the robot's operating deck. In other words, frame 60 (FIGS. 2 and 3) simply replaces what would have been a fixed nest, to hold the microplate being used for the test. [0029] This simplicity eliminates the necessity of physically moving the microplate from the station where it receives the reagent, without magnetization, to a station with magnetization. The invention permits the system control to apply magnetization on demand where and when it is required. [0030] In the embodiments of the present invention described above, it will be recognized that individual elements and/or features thereof are not necessarily limited to a particular embodiment but, where applicable, are interchangeable and can be used in any selected embodiment even though such may not be specifically shown. [0031] Terms such as “upper”, “lower”, “inner”, “outer”, “inwardly”, “outwardly”, “vertical”, “horizontal”, and the like, when used herein, refer to the positions of the respective elements shown on the accompanying drawing figures and the present invention is not necessarily limited to such positions. [0032] It will thus be seen that the objects set forth above, among those elucidated in, or made apparent from, the preceding description, are efficiently attained and, since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matter contained in the above description or shown on the accompanying drawing figures shall be interpreted as illustrative only and not in a limiting sense. [0033] It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

In a preferred embodiment, an apparatus for automated magnetic separation of materials in laboratory trays, including: a frame upon an upper surface of which a multiwell laboratory tray may be placed; a base plate on which is mounted a plurality of upstanding magnets disposed below the upper surface; and apparatus to raise the base plate such as to insert the upstanding magnets into interwell spaces in the laboratory tray.

TECHNICAL FIELD [0001] The invention relates to a broadcast communication system architecture and receiving terminals used within the system, and more particularly to a digital television (TV) network architecture and client terminals. BACKGROUND [0002] The conventional terrestrial digital TV transmission systems widely employ a single-frequency network architecture, namely, TV towers at different locations transmit the same signal at the same frequency simultaneously. [0003] The disadvantage is that the number of the transmit towers and the transmit power are subject to certain constraints. For urban topography, there will be many shadow areas for indoor reception, and for rural topography, the coverage range will be limited in some extent. On the other hand, the conventional digital TV transmission system is for one-way broadcast. This one-way broadcast mode transmits a fixed number of video programs with limited bandwidth, without taking into account the specific service needs of users, e.g., two-way services such as video on-demand, information customization, games, etc. SUMMARY [0004] The invention intends to provide a digital TV network architecture and client terminal, to solve the inadequacy of the only existing broadcast approach, the incapability in integrating and sharing with other networks, and the improper allocation of broadcast and network resources. [0005] According to the aforementioned purpose, a client terminal according to this invention is implemented, wherein the client terminal comprises: a first receiving module for connecting with a broadband communication network, and a second receiving module for connecting with a digital TV broadcast system, wherein the client terminal is operable to receive, via the second receiving module, an information index transmitted by the digital TV broadcast system, and to retrieve corresponding information content from the broadband communication network via the first receiving module based on the information index. [0006] According to the above main features, the client terminal receives, via the second receiving module, the content transmitted by the digital TV broadcast system, and selectively stores and recommends the content according to a user's behavior habits. [0007] According to the above main features, the client terminal is operable to directly retrieve information content from the broadband communication network via the first receiving module. [0008] According to the above main features, the broadband communication network deploys an edge server that is close to the client terminal, wherein the client terminal connects to the broadband communication network via the edge server. [0009] According to the above main features, the digital TV broadcast system coordinates with the broadband communication network by connecting to a content clustering server, wherein the content clustering server chooses popular content from a plurality of data sources and generates an information index, wherein the information index of the popular content is sent to the client terminal via the digital TV broadcast system and the second receiving module, such that the client terminal is operable to retrieve the corresponding popular content from the edge server via the first receiving module based on the information index of the popular content. [0010] According to the above main features, the client terminal is connected to the digital TV broadcast system through a wireless digital broadcast channel. [0011] According to the above main features, the client terminal selectively downloads some of the popular content from the edge server to the client terminal according to a user's behavior habits, and recommends the content to the user. [0012] According to the aforementioned purpose, a digital TV broadcast system coordinated with a broadband communication network according to this invention is implemented, for providing information to a client terminal, wherein the broadband communication network comprises an edge server that is close to the client terminal, wherein a bidirectional information channel is provided between the client terminal and the edge server, a broadcast information channel is provided between the digital TV broadcast system and the edge server, and a broadcast information channel is provided between the digital TV broadcast system and the client terminal. [0013] According to the above main features, the digital TV broadcast system coordinates with the broadband communication network by connecting to a content clustering server, wherein the content clustering server performs clustering analysis on multimedia content from a plurality of data sources based on the sources of the content, analysis and prediction of relevance between the content and users, and feedback information to the content including user's click response, to identify the multimedia content as popular content or normal content, so as to choose, classify and index the popular content. [0014] According to the above main features, the content clustering server sends the popular content to the edge server through the information channel between the digital TV broadcast system and the edge server. [0015] According to the above main features, the digital TV broadcast system sends the popular content or its index directly to the client terminal through the information channel between the digital TV broadcast system and the client terminal. [0016] According to the above main features, the digital TV broadcast system sends the popular content or its index to the client terminal through the information channel between the digital TV broadcast system and the client terminal, wherein the client terminal retrieves the corresponding popular content from the edge server via the information channel between the client terminal and the edge server based on the index of the popular content. [0017] According to the above main features, the content clustering server sends all the content to the broadband communication network, and the client terminal is connected to the broadband communication network via the information channel between the client terminal and the edge server. [0018] According to the above main features, the information channel between the digital TV broadcast system and the edge server comprises a cable digital broadcast channel, a satellite digital broadcast channel, or a terrestrial digital broadcast channel. [0019] According to the above main features, the information channel between the digital TV broadcast system and the client terminal comprises a wireless digital broadcast channel. [0020] According to the above main features, the information channel between the digital TV broadcast system and the edge server and the information channel between the digital TV broadcast system and the client terminal are two logical channels on one physical channel. [0021] According to the above main features, the information channel between the digital TV broadcast system and the edge server and the information channel between the digital TV broadcast system and the client terminal are two different physical channels. [0022] According to the aforementioned purpose, an information transmission network according to the invention is implemented, for providing information to a client terminal, wherein the information transmission network comprises a broadband communication network and a digital TV broadcast system, wherein the broadband communication network comprises an edge server that is close to the client terminal, wherein a bidirectional information channel is provided between the client terminal and the edge server, a broadcast information channel is provided between the digital TV broadcast system and the edge server, and a broadcast information channel is provided between the digital TV broadcast system and the client terminal. [0023] According to the above main features, the information transmission network further comprises a content clustering server connected to the broadband communication network and the digital TV broadcast system, wherein the content clustering server performs clustering analysis on multimedia content from a plurality of data sources based on the sources of the content, analysis and prediction of relevance between the content and users, and feedback information to the content including user's click response, to identify the multimedia content as popular content or normal content, so as to choose, classify and index the popular content. [0024] According to the above main features, the content clustering server sends the popular content to the edge server through the information channel between the digital TV broadcast system and the edge server. [0025] According to the above main features, the digital TV broadcast system sends the popular content or its index directly to the client terminal through the information channel between the digital TV broadcast system and the client terminal. [0026] According to the above main features, the digital TV broadcast system sends the popular content or its index to the client terminal through the information channel between the digital TV broadcast system and the client terminal, wherein the client terminal retrieves the corresponding popular content from the edge server via the information channel between the client terminal and the edge server based on the index of the popular content. [0027] According to the above main features, the content clustering server sends all the content to the broadband communication network, and the client terminal is connected to the broadband communication network via the information channel between the client terminal and the edge server. [0028] According to the above main features, the information channel between the digital TV broadcast system and the edge server comprises a cable digital broadcast channel, a satellite digital broadcast channel, or a terrestrial digital broadcast channel. [0029] According to the above main features, the information channel between the digital TV broadcast system and the client terminal comprises a wireless digital broadcast channel. [0030] According to the above main features, the information channel between the digital TV broadcast system and the edge server and the information channel between the digital TV broadcast system and the client terminal are two logical channels on one physical channel. [0031] According to the above main features, the information channel between the digital TV broadcast system and the edge server and the information channel between the digital TV broadcast system and the client terminal are two different physical channels. [0032] According to the aforementioned purpose, a digital TV heterogeneous network architecture of the invention is implemented for providing digital TV content to a client terminal, wherein the digital TV heterogeneous network architecture comprises: a transmission control module, a broadcast TV network and a secondary network, wherein both the broadcast TV network and the secondary network are connected to the transmission control module, wherein the broadcast TV network is a unidirectional transmission network for sending the digital TV content to the client terminal directly, and the secondary network is a bidirectional network for transmitting the digital TV content to the client terminal and for transmitting control information between the client terminal and the transmission control module, wherein the transmission control module governs the digital TV content to be transmitted via the broadcast TV network and the secondary network. [0033] According to the above main features, the broadcast TV network further comprises a multiplexing and distribution module connected to the transmission control module, for performing channel multiplexing and content distribution for the content output from the transmission control module; wherein the channel multiplexing means that a plurality pieces of content might occupy one frequency resource chronologically or a plurality pieces of content might occupy one time block at different frequency resources. [0034] According to the above main features, the control information comprises a VOD request, a broadcast content retransmission request, or a direct video content request. [0035] According to the above main features, the digital TV content comprises broadcast content as well as VOD content for the client terminal. [0036] According to the above main features, the secondary network comprises a 3G, LTE, or WiFi network and the wired Internet, wherein the 3G, LTE, or WiFi network is used to connect the client terminal with the Internet, wherein the client terminal uploads control information or video content to the Internet via the 3G, LTE, or WiFi network. The Internet delivers feedback information, broadcast retransmission content or direct video content from the transmission control module to the client terminal via the 3G, LTE, or WiFi network; wherein the feedback information comprises acceptance, waiting, or timeout of a VOD request, acceptance, waiting, or timeout of a broadcast content retransmission request, or acceptance, waiting, or timeout of a direct content request. [0037] According to the above main features, the client terminal further comprises a storage device, for storing the digital TV content transmitted to the client terminal from the broadcast TV network or the secondary network. [0038] According to the above main features, the broadcast TV network architecture further comprises a content classification and preparation module connected to the transmission control module, for classifying acquired digital TV content and further creating an index label for each piece of multimedia content. [0039] According to the above main features, the broadcast TV network architecture further comprises a content acquisition module connected to the content classification and preparation module, for acquiring digital TV content from various sources. [0040] According to the above main features, the secondary network has a plurality of information transmission channels, and the client terminal comprises an evaluation unit for evaluating a channel condition in real-time based on return channels of the information transmission channels, so as to select an optimal information transmission channel. [0041] According to the aforementioned purpose, a terrestrial digital TV network architecture according to this invention is implemented, wherein the terrestrial digital TV network architecture comprises: a TV tower base station and a client terminal; wherein a downlink at a first frequency and an uplink at a second frequency are employed between the TV tower base station and the client terminal. [0042] According to the above main features, the downlink carries broadcast information transmitted to all users in a broadcast mode and proprietary information specific to individual users transmitted in a broadcast or directional transmission mode; and the uplink is accessed according to a time-frequency resource table specified individually and delivered on the downlink. [0043] According to the above main features, an uplink signal is transmitted by the client terminal in a directional transmission mode; wherein the directional transmission mode is implemented by a directional antenna or through beamforming of an antenna array. [0044] According to the above main features, a wireless repeater is also included, wherein the TV tower base station transmits a broadcast signal to the wireless repeater, which forwards the broadcast signal to the client terminal; wherein the client terminal transmits an uplink signal to the wireless repeater, which forwards the uplink signal to the TV tower base station. [0045] According to the above main features, the wireless repeater comprises a pair of back-to-back wireless access points, one for receiving and the other for transmitting; the wireless repeater utilizes analog intra-frequency forwarding, analog inter-frequency forwarding, digital intra-frequency forwarding, or digital inter-frequency forwarding, or utilizes Bluetooth or Wifi forwarding. [0046] According to the aforementioned purpose, a TV tower base station of this invention is implemented for transceiving signals with a client terminal, wherein: the TV tower base station comprises a receiving device and a transmitting device, wherein the transmitting device transmits information to the client terminal at a first frequency, and the receiving device receives information transmitted from the client terminal at a second frequency. [0047] According to the above main features, the information transmitted by the transmitting device comprises broadcast information transmitted to all users in a broadcast mode, and proprietary information specific to individual users transmitted in a broadcast or directional transmission mode. [0048] According to the above main features, the receiving device receives the information transmitted from the client terminal according to a time-frequency resource table for the client terminal. [0049] According to the aforementioned purpose, a client terminal of this invention is implemented for transceiving signals with a TV tower base station, wherein: the client terminal comprises a receiving device and a transmitting device, wherein the receiving device receives information transmitted from the TV tower base station at a first frequency, and the transmitting device transmits information to the TV tower base station at a second frequency. [0050] According to the above main features, the client terminal transmits information to the TV tower base station in a directional transmission mode, wherein the directional transmission mode is implemented by a directional antenna or through beamforming of an antenna array. [0051] With the technical solutions of the invention, the integration of the broadcast network and other networks is provided, to support multiple network access modes for users, and to provide accurate, efficient, and high quality information services to users with best efforts. Moreover, such heterogeneous architectures utilize the WiFi/GPRS/3G, LTE and broadcast networks in a site-specific way to provide a collaborative coverage to solve the blind spots and shadows in the cities. In addition, the network architecture of the invention can support an uplink of broadcasting and also utilizes the different advantages of various networks in coverage range, transmission speed, mobility support, QoS support, setup cost, and targeting market, which are complementary to each other, thereby providing services with more variety, higher quality, and lower price for users. BRIEF DESCRIPTION OF THE DRAWINGS [0052] In this invention, like reference numerals refer to like parts throughout the drawings, in which: [0053] FIG. 1 is a schematic diagram of an information transmission network combining a digital TV broadcast system and a broadband communication network according to a first embodiment of the invention; [0054] FIG. 2 is a schematic block diagram of a Broadcast-to-Client channel and a Broadcast-to-Server channel in FIG. 1 ; [0055] FIG. 3 is a schematic diagram of a digital TV heterogeneous network architecture according to a second embodiment; [0056] FIG. 4 is a schematic diagram of a network architecture according to a third embodiment of the invention; [0057] FIG. 5 is a schematic diagram of a network architecture according to a fourth embodiment of the invention. DETAILED DESCRIPTION [0058] The technical solutions of this invention will be further described below in connection with the figures and embodiments. [0059] As seen from the prediction in the Background, the explosive increase in demands for video data services places a heavy burden on the broadband communication network; while the high homogenity of a large amounts of data services makes it possible for the digital TV broadcast system to assist the broadband communication network. Accordingly, the digital TV broadcast system and the broadband communication network of multimedia data are inevitably integrated and complement each other. Thus, this invention proposes a network architecture coordinated with the broadband communication network, and is particularly applicable in the digital TV broadcast system. [0060] As shown in FIG. 1 , with a network architecture that coordinates the broadband communication network and the digital TV broadcast system, the information transmission network of this invention is operable for providing information to a client terminal, and mainly includes two sub-networks, the broadband communication network and the digital TV broadcast system. The broadband communication network includes a plurality of servers in the network. Particularly in this invention, a server close to the client terminal is referred as an edge server, wherein a bidirectional information channel is provided between the client terminal and the edge server, an information channel is provided between the digital TV broadcast system and the edge server, and an information channel is provided between the digital TV broadcast system and the client terminal. [0061] The edge server is deployed at the backend of the digital TV broadcast system and the broadband communication network. The digital TV broadcast system is connected to the client terminal, forming a Broadcast-to-Client (BC) channel, the digital TV broadcast system is connected to the edge server, forming a Broadcast-to-Server (BS) channel, and the client terminal is connected to the edge server, forming a Server-to-Client (SC) channel. [0062] Among the above three channels, the SC channel is a bidirectional channel, for interconnectivity between the client and the broadband communication network. The BC channel and the BS channel may be two logical channels on one physical channel, wherein the BC channel and the BS channel multiplexes the physical channel by time-division multiplexing or frequency-division multiplexing. In another aspect, the BC channel and the BS channel may simply be two different physical channels. Regardless the form of the BC channel and the BS channel, the BC channel and the BS channel are not limited to unidirectional channels. In other words, both the BC channel and the BS channel may include an uplink, wherein the uplink and downlink of the BC channel and the BS channel are differentiated by different frequency bands. [0063] In consideration of the unidirectional or bidirectional characteristics of the BC channel, the BS channel and the SC channel, the BS channel may be a cable digital broadcast channel, or a satellite digital broadcast channel, or a terrestrial digital broadcast channel, the BC channel may be a wireless digital broadcast channel, and the SC channel may be a common wired network channel, or a Wifi channel, etc. [0064] The multimedia data firstly undergoes content clustering. Accordingly, the information transmission network of this invention further comprises a content clustering server, which is connected to the broadband communication network and the digital TV broadcast system, and which is deployed at frontend of the digital TV broadcast system and the broadband communication network. [0065] The content clustering server first analyzes popularity of various multimedia data based on the sources of the multimedia content, analysis and prediction of relevance between the content and users, and feedback information to the content including user's click response, and chooses the content that most people concern (i.e., popular content), such that the popular content is separated from normal content. Next, the popular content is further processed to extract key words of the multimedia data based on the popularity characteristics of the multimedia data, which may then be indexed by the key words, and all the indices are managed collectively on the content clustering server. [0066] For each multimedia data label, the content clustering server needs to continuously update its popularity, so as to update the key words and the corresponding index. Accordingly, the popularity and index of multimedia data are dynamic parameters. For example, in a period of time, some multimedia content is concerned by many people, and the multimedia content becomes popular. After a time period, the concern for the multimedia content decreases, and then the content clustering server may modify the label of the multimedia content from popular to normal. Finally, the digital TV broadcast system assists the broadband communication network to deliver the popular content. [0067] During the data delivery, the content clustering server groups the multimedia data into two clusters: one cluster for the popular content in all the multimedia data and its information index, the other cluster for content of all the multimedia data. The content clustering server delivers the two clusters through two different networks. [0068] The first network is the digital TV broadcast system, for delivering the popular content and/or the information index of the content. The transmission on the digital TV broadcast system is carried through a BS channel and a BC channel. The BS channel transmits the popular content directly to the edge server close to the terminal, and the BC channel transmits the popular content and/or the information index of the content directly to the client terminal. Alternatively, the client terminal may retrieve the full information of the corresponding popular content from the edge server via the SC channel based on the information index of the popular content. [0069] The secondary network is the broadband communication network, for delivering all the multimedia data and the information index thereof. The content clustering server delivers all the content and the information index thereof to the broadband communication network. The edge server is capable of both receiving the BS channel and accessing the broadband communication network. The client terminal connects to the broadband communication network via the SC channel, so as to retrieve the information index of all the multimedia data and the full content. [0070] As a preferred embodiment of this invention, FIG. 2 illustrates the content clustering, BS channel and BC channel which constitute three essential parts of this invention. The BS channel may be a cable digital broadcast channel, a satellite digital broadcast channel, or a terrestrial digital broadcast channel, which is of high spectrum efficiency. A large amount of popular multimedia data can be delivered to the edge server directly via the BS channel. The BC channel merely employs wireless digital broadcasting, can be widely deployed, can accommodate different requirements of terminals, and benefits power saving in some extent. [0071] Broadcasting is characterized in the point-to-plane information transmission. The delivery of the popular content through the digital TV broadcast system may offload a high traffic from the broadband communication network. The client terminal receives the broadcast popular content and its information index via the BC channel, may selectively store some popular content for recommendation according to user's behavior habits, and may also store the index information of the popular content. The user may select information based on the recommendation from the client terminal, the index information or other requirements. Although the user does not concern the source of the information, the three different access modes can ensure the user to obtain the required information more quickly and accurately. Based on the user's needs, the user may decide whether to browse the recommended content, whether to browse all the content of the index information, or whether to inquire about other information. If the user simply browses the content recommended by the terminal, the information may be found on the client terminal itself; if the user is interested in specific content of the index information, such information may be retrieved from the nearest edge server via the SC channel; or if the user want to query other content information, the Internet may be accessed via the edge server for information query and browsing. [0072] The integration of the digital TV broadcast system with the broadband communication network is a trend in the next generation of network architecture. Such an architecture may leverage the characteristic of point-to-plane transmission of the digital TV broadcast system, separate and index the popular content by the content clustering server, and deliver the content that most people concern directly via the BC channel, thereby significantly reducing the traffic load on the broadband communication network. By analyzing the user's behaviors, the terminal may store and recommend the content that the user may concern. Meanwhile, the content may be delivered to the edge server via the BS channel, so as to reduce the access distance between the user and most content. Such a digital TV broadcast architecture provides multiple access modes for users, and is capable of providing accurate, efficient and high quality information services for users with best efforts. The digital TV broadcast system combined with the broadband communication network becomes the information highway in the new era, whereby a large amount of multimedia data may be delivered to the user quickly and accurately by broadcasting. [0073] As the continuous development of digital TVs and the trends of diversity and interaction of networks, the integration and heterogeneity based on the coexistence of multiple network become a considerable trend of the future digital TV wireless signal communication development. The various networks have different advantages in coverage range, transmission speed, mobility support, QoS support, setup cost, and targeting market, and are complementary to each other. The network integration intends to utilize the complementary characteristics of the heterogeneous networks, so as to provide services with more variety, higher quality, and lower prices for users. [0074] A terrestrial broadcast TV network architecture established with the concept of heterogeneous networks and having a return link and a collaborative coverage function is shown in FIG. 3 , and mainly comprises a content acquisition module, a content classification and preparation module, a transmission control module, a broadcast TV network, a secondary network, a client terminal and a storage device. The digital TV content of this invention comprises broadcast content as well as VOD content for the client terminal. In particular, as an alternative embodiment of this invention, the broadcast TV network is a broadcast network, the secondary network is a 3G, LTE or WiFi network. Alternatively, the secondary network may be an analog intra-frequency (on-channel) forwarding, digital intra-frequency (differential-channel) forwarding, or digital inter-frequency forwarding communication system, and this invention is not so limited. The connections and functions of these modules are illustrated individually below. [0075] The content acquisition module is connected to the content classification and preparation module, and acquires resource information mainly by means of photography, audio recording, computer synthesis and so on, creates multimedia content from the resource information by post-processing such as editing, composing, clipping, rendering, etc., and sends the created media content a content classification and preparation module. [0076] The content classification and preparation module has a receiving terminal connected to the content acquisition module, and a sending terminal connected to the transmission control module. The content classification and preparation module is primarily used to classify the resulting multimedia content, e.g., according to the characteristics of video source effects: distinguishing between real-time and non real-time services, distinguishing the definition (Ultra HD, HD, SD), distinguishing between the dimensions (3D, 2D); according to the categories of the video source content: distinguishing among sport, financial, political, social, educational, historical, variety, drama, film and TV, and so on. Based on the above, further subdivision may be performed. Finally, an index label is created for each video source, which is packaged separately in accordance with the stream format. [0077] The transmission control module controls both the broadcast TV network and the secondary network to transmit content signals to the client terminal. In this invention, multiple broadcast TV networks and secondary networks may coexist, for example, multiple broadcast networks and multiple 3G or LTE networks, etc. may coexist, at least one or more or all of which has information transmissions being controlled by the transmission control module. The transmission control module communicates control signals and content signals with the client terminal via at least one or more or all of the secondary networks. However, for the broadcast TV network, such as the broadcast network, the transmission control module transmits only content signals. In this invention, the control information comprises a VOD request, a broadcast content retransmission request, or a direct video content request. [0078] As a preferred embodiment of this invention, the broadcast TV network (the broadcast network) also includes a multiplexing and distribution module. The transmission control module provides broadcast multimedia content to the multiplexing and distribution module of the broadcast system. The broadcast multimedia content is service content being broadcast, including normal broadcast services on various channels and user's video on demand (VOD) service content on special channels. The multiplexing and distribution module performs channel multiplexing and matching, etc., for the broadcast content provided by the transmission control module (including normal video services, Ultra HD, 3D, special VOD services, etc.), which is then distributed to clients such as stationary TVs, mobile phones, mobile terminals by radio frequency signal broadcasting. The channel multiplexing herein means that a plurality pieces of content might occupy one frequency resource chronologically or a plurality pieces of content might occupy one time block on different frequency resources. [0079] The secondary network of this invention has a plurality of information transmission channels, typically via a 3G, LTE or WiFi network, connected to the transmission control module. Alternatively, the secondary network may be divided into a frontend and a backend, wherein the frontend is the Internet, and the backend includes a 3G, LTE or WiFi network. The transmission control module has access to the frontend, i.e., the Internet, and the client terminal has access to the backend, i.e., access to a 3G, LTE or WiFi network, etc. The frontend Internet is connected to the backend 3G, LTE or WiFi network, to communicating multimedia services and control signals therebetween. [0080] In this invention, the feedback information comprises acceptance, waiting, or timeout of a VOD request, acceptance, waiting, or timeout of a broadcast content retransmission request, or acceptance, waiting, or timeout of a direct content request. The client terminal may upload control information or video content to the Internet via the 3G, LTE, or WiFi network. The Internet may deliver feedback information, broadcast retransmission content or direct video content from the transmission control module to the client terminal via the 3G, LTE, or WiFi network. [0081] The transmission control module provides multimedia content to the Internet module, and also exchanges control signaling with the Internet. The transmission control module receives control signaling sent from the Internet, including an on-demand (VOD) request, to control the on-demand content output from the transmission control module to the multiplexing and distribution module. After receiving a request from the Internet, the transmission control module will feedback its processing result to the Internet by control signaling, “acceptance” or “waiting”. If a predetermined latency expires, “no response” is returned, and then the user may resend the request. [0082] This invention selects the 3G, LTE or WiFi network because 3G, LTE/WiFi base stations are densely deployed in urban regions, thus almost having a seamless coverage. In one aspect, these modules receive control signals from clients (stationary TVs, mobile terminals, etc) via radio frequency, including on-demand requests, direct content requests, and retransmission requests due to a broadcast content package loss, etc, and also (optionally) receive content uploaded from clients, and further upload the content to the Internet. In another aspect, these modules also receive feedback control signaling from the Internet, including a result feedback for the on-demand request (acceptance, waiting, or no response), a feedback for the direct content request (acceptance, waiting, or no response), and a feedback for a lost package retransmission request (acceptance, waiting, or no response), receive the content requested by the client provided from the Internet, and transmit the information received from the Internet module to the requesting client terminal via a radio frequency. [0083] The client terminal has access to the 3G, LTE or WiFi network, and is equipped with a built-in storage device or connected to an external storage device, for storing information received from the broadcast network or the Internet. In another aspect, the client terminal includes an internal evaluation unit for evaluating a channel condition in real-time based on return channels of the information transmission channels of the secondary network, so as to select an optimal information transmission channel. [0084] As another aspect of this invention, the above terrestrial broadcast TV network architecture has two primary control modes. [0085] One control mode is that the secondary network assists the broadcast TV network to achieve collaborative coverage. In particular, the client terminal assesses the broadcast information received from the broadcast network in real-time to identify missing signals in the broadcast information, and sends a retransmission signal to the transmission control module via the 3G, LTE or WiFi network and then the Internet, whereby the transmission control module transmits the missing signals to the client terminal through the Internet and then the 3G, LTE or WiFi network. [0086] Another control mode is that the secondary network controls the broadcast TV network or the secondary network itself. In particular, the client terminal sends an on-demand control signal to the transmission control module through the 3G, LTE or WiFi network and then the Internet, and the transmission control module transmits the on-demand content to the client terminal through the broadcast network, or again through the Internet and then the 3G, LTE or WiFi network. [0087] The two control modes of this invention are illustrated below by embodiments. [0088] In one aspect, the user receives and watches multimedia content through the broadcast network. When a packet loss occurs in the multimedia content received through the broadcast network due to channel environment deterioration, a retransmission request for the lost content (simply referred to lost packet retransmission request) might be sent to the transmission control module through the 3G, LTE or Wifi wireless network and then the Internet. Upon receiving the request, the transmission control module provides a retransmission of the lost content to the client terminal according to normal criteria (for example, the user request arriving first will be processed first), or prioritization criteria (for example, premium users and privileged users are prioritized). If the user request has to wait, the control signaling feedback to the user is waiting, if the user request can be processed directly, then the control signaling of acceptance is returned, or if the user has been waiting for more than a preset value, then the control signaling of “no response” is returned. This service achieves collaborative coverage of heterogeneous networks and the broadcast network, to overcome the deficiency of packet loss in coverage shadow of the broadcast network. [0089] In another aspect, the user may send a video on-demand (VOD) request to the transmission control module through the 3G, LTE or Wifi wireless network and then the Internet, wherein after receiving the request, the transmission control module controls the on-demand content to be transmitted on the broadcast link, and transmits the on-demand content to the user through the broadcast network timely, so as to meet the on-demand needs of the client terminal. This functionality integrates the heterogeneous networks and the broadcast network, enabling bidirectional transmissions with the client end. [0090] In addition, the client terminal may send a direct content request to the transmission control module through the 3G, LTE or Wifi wireless network and then through the Internet. This service intends to enable the client terminal to obtain content from the Internet resources directly. After receiving the request, the transmission control module provides a content service directly to the client terminal based on normal criteria (for example, the user request arriving first will be processed first), or prioritization criteria (for example, premium users and privileged users are prioritized). Similarly, the control signaling may be acceptance, waiting or no response. [0091] When the client terminal selects the 3G, LTE or Wifi access mode, in accordance with the optimal channel criterion, the client terminal evaluates the channel condition in real-time based on the 3G, LTE or Wifi return channel to select an optimal interaction mode. If the client terminal is a mobile device and a network handover is required, it follows the optimal channel criteria for handover. [0092] The terrestrial digital TV network architecture of the invention is primarily applicable to some regions with limited hardware environment, for example in rural areas, without too many obstacles and with a relatively simple channel environment. In this circumstance, the network architecture of the invention applies in two scenarios as following. [0093] When the user is near the TV tower base station and has a Light-of-Sight transmission condition, a direct return uplink may be added on the basis of the broadcast link. [0094] When the user is far from the TV tower base station, or there is no Light-of-Sight transmission between the user and the TV tower base station, a return uplink with repeaters may be added on the basis of the broadcast link. [0095] The network architectures of the invention operable in the above two scenarios are illustrated below with two embodiments. [0096] As shown in FIG. 4 , the network architecture of the invention mainly includes a TV tower base station (for example, a broadcast signal TV tower base station) and a client terminal, as well as an uplink and a downlink between the TV tower base station and the client terminal. When the user is near the TV tower base station and might be in a Light-of-Sight transmission condition, e.g., the user is located within 10 km from the broadcast TV tower base station, a direct return uplink may be added on the basis of broadcast link. [0097] The downlink and uplink utilize a combination of TDD and FDD, wherein the downlink is on a different frequency band from the uplink. The downlink carries broadcast information transmitted to all users in a broadcast mode and proprietary information specific to individual users transmitted in a broadcast or directional transmission mode. The coverage of downlink information is improved by transmitting high rate signals through transmit diversity of the TV tower base station, which is suitable for immersive applications such as SHDTV, HDTV and 3DTV, as well as Rich Media applications. The uplink is accessed according to information in a time-frequency resource table specified individually and delivered on the downlink. [0098] The uplink signal is transmitted by the client terminal in a directional transmission mode, which can be implemented by a directional antenna or through beamforming of an antenna array, thus achieving high system power efficiency, far transmission distance, and security. The modulation and demodulation for the uplink burst transmissions rely on the PSK modulation method with a relatively low peak-to-average power ratio to improve power efficiency. The uplink also employs a multi-rate Turbo convolutional coding technology, and utilizes the long preamble sequence readily to be captured. The MAC layer protocol for the uplink employs the DOCSIS protocol which has been applied in cable TVs, and employs the combined “contention and reservation” resource allocation method, wherein the contention method may be utilized for short data service like a VOD request, and the resource reservation method may be utilized for real-time video call, video interaction service, etc. The frame structure defines essential signaling frames: ranging frame and MAP frame. By division of time slots and subcarrier clusters, it is possible to support a plurality of multi-access modes, such as TDMA, OFDMA or SC-FDMA. [0099] As shown in FIG. 5 , when the user is far from the TV tower base station, for example, when the user is about 10-35 km from the broadcast TV tower base station, there is typically no Light-of-Sight (LoS) path due to occlusion. On the basis of the first embodiment, the invention employs a network architecture with wireless repeaters to extend the coverage of downlink transmissions (there may be multiple wireless repeaters, without being limited to the single repeater mode as shown in FIG. 5 ). Typically, the wireless repeater includes a pair of back-to-back wireless access points (APs), one for receiving, and the other for transmitting. [0100] In particular, the wireless repeater may use one or more of various wireless forwarding modes, such as analog intra-frequency forwarding, analog inter-frequency forwarding, digital intra-frequency forwarding, digital inter-frequency forwarding, or Bluetooth or Wifi forwarding, etc. The TV tower base station transmits a broadcast signal to the wireless repeater, which forwards the broadcast signal to the client terminal; the client terminal transmits an uplink signal to the wireless repeater, which forwards the uplink signal to the TV tower base station. [0101] Also, when there is no Light-of-Sight transmission in the uplink transmission path, the return uplink with a wireless repeater as in FIG. 5 may be employed to enable the uplink transmission between the client terminal and the TV tower base station. Selecting the coding with a low constellation and a low bit rate can further improve the uplink coverage range, thereby enhancing the capability of direct return uplink. [0102] As known from the above, the TV tower base station implementing this invention includes a receiving device (not shown) and a transmitting device (not shown), wherein the transmitting device transmits information to the client terminal at a first frequency in a broadcast mode, and the receiving device receives information transmitted from the client terminal at a second frequency. Moreover, the information transmitted from the transmitting device in the broadcast mode includes broadcast information transmitted to all users and proprietary information specific to individual users. The receiving device receives the information transmitted from the client terminal according to a time-frequency resource table for the client terminal. [0103] Meanwhile, the client terminal implementing this invention also includes a receiving device (not shown) and a transmitting device (not shown), wherein the receiving device receives information sent by the TV tower base station in a broadcast mode at a first frequency, and the transmitting device transmits information to the TV tower base station at a second frequency. Moreover, the client terminal transmits information to the TV tower base station in a directional transmission mode, which can be implemented by a directional antenna or through beamforming of an antenna array. [0104] Those skilled in the art shall appreciate that the specification above illustrates one or more of the numerous embodiments of this invention, rather than limiting thereof. Any equivalent modification, variations and equivalents to the above embodiments, that are consistent with the substantial spirit and scope of this invention, fall within the scope of the claims of this invention.

This invention discloses a digital TV broadcast system coordinated with a broadband communication network, an information transmission network in which the broadcast system is applied, a digital TV heterogeneous network architecture, and a client terminal used in each of the above network systems. The various broadcast system architectures of the invention adopt the design concept of heterogeneous network which integrates a broadcast network with other networks, for example, a communication network, the Internet and the like, to form a heterogeneous network architecture coordinating various networks. Meanwhile, the usage in bad conditions are taken into account, and a broadcast TV system which enables uplink transmission by using a broadcast link is designed. The terminal of the invention is a terminal applicable in these heterogeneous network architectures, is capable of receiving signals transmitted from various networks, and can enable flexible receiving and access modes with a series of control means. The network system and client terminal of the invention can achieve an optimized allocation of network resources, save spectrum resources, and enable optimized transmission and management of information resources.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to thiophenesulfonamides that have carbonic anhydrase inhibition activity and are useful as anti-glaucoma agents. 2. Background of the Art Glaucoma is an ocular disorder associated with elevated intraocular pressures which are too high for normal function and may result in irreversible loss of visual function. If untreated, glaucoma may eventually lead to blindness. Ocular hypertension, i.e., the condition of elevated intraocular pressure without optic nerve head damage or characteristic glaucomatous visual field defects, is now believed by many ophthalmologists to represent the earliest phase of glaucoma. Many of the drugs formerly used to treat glaucoma proved not entirely satisfactory. Indeed, few advances were made in the treatment of glaucoma since pilocarpine and physostigmine were introduced. Only recently have clinicians noted that many β-adrenergic blocking agents are effective in reducing intraocular pressure. While many of these agents are effective in reducing intraocular pressure, they also have other characteristics, e.g. membrane stabilizing activity, that are not acceptable for chronic ocular use. (S)-1-tert-Butylamino-3-[(4-morpholino-1,2,5-thiadiazol-3-yl)oxy]-2-propanol, a β-adrenergic blocking agent, was found to reduce intraocular pressure and to be devoid of many unwanted side effects associated with pilocarpine and, in addition, to possess advantages over many other β-adrenergic blocking agents, e.g., to be devoid of local anesthetic properties, to have a long duration of activity, and to display minimal tolerance. Although pilocarpine, physostigmine and the β-adrenergic blocking agents mentioned above reduce intraocular pressure, none of these drugs manifests its action by inhibiting the enzyme carbonic anhydrase and, thereby, impeding the contribution to aqueous humor formation made by the carbonic anhydrase pathway. Agents referred to as carbonic anhydrase inhibitors, block or impede this inflow pathway by inhibiting the enzyme, carbonic anhydrase. While such carbonic anhydrase inhibitors are now used to treat intraocular pressure by oral, intravenous or other systemic routes, they thereby have the distinct disadvantage of inhibiting carbonic anhydrase throughout the entire body. Such a gross disruption of a basic enzyme system is justified only during an acute attack of alarmingly elevated intraocular pressure, or when no other agent is effective. Topically effective carbonic anhydrase inhibitors are reported in U.S. Pat. Nos. 4,386,098; 4,416,890; and 4,426,388. The compounds reported therein are 5 (and 6)-hydroxy-2-benzothiazolesulfonamides and acyl esters thereof. Additionally, U.S. Pat. No. 4,544,667 discloses a series of benzofuran-2-sulfonamides, and U.S. Pat. Nos. 4,477,466; 4,486,444; 4,542,152; and 4,585,787 disclose 5-phenylsulfonylthiophene-2-sulfonamides and 5-benzoylthiophene-2-sulfonamides and alkanoyloxy derivatives thereof which are reported to be topically effective carbonic anhydrose inhibitors useful in the treatment of elevated intraocular pressure and glaucoma. Finally, U.S. Pat. No. 4,914,111 reports that thiophene or furan-2-sulfonamides, having a 4-benzyl substituent are effective for the topical treatment of elevated intraocular pressure and glaucoma. In view of the above, it is clear that a great deal of research has been carried out on the use of sulfonamides for the topical treatment of glaucoma. Furthermore, certain thiophenesulfonamides have been suggested for the topical treatment of glaucoma. However, the use of 3-thiophenesulfonamides has not been suggested for use in the topical treatment of glaucoma. Therefore, it is one objective of this invention to provide 3-thiophenesulfonamides for the treatment of glaucoma. It is another object of this invention to provide compounds having carbonic anhydrase inhibition activity. Another object of this invention is to provide a method of inhibiting carbonic anhydrase activity to thereby treat glaucoma. Other objects and advantages of the instant invention will become apparent from a careful reading of the specification below. SUMMARY OF THE INVENTION The present invention provides novel compounds having carbonic anhydrase inhibition activity and useful in the treatment of glaucoma. These compounds are represented by the structural formula: ##STR2## wherein R 1 and R 2 are independently (a) hydrogen; or (b) OR 4 , wherein R 4 is hydrogen or C 1-7 alkyl or C 1-3 alkylcarbonyl or phenylcarbonyl or phenyl; or (c) NR 5 R 6 , wherein R 5 and R 6 are independently hydrogen, or C 1-7 alkyl, or C 1-7 alkyl substituted with one or more halogen or OR 4 ; or (d) --COR 7 , wherein R 7 is hydrogen, C 1-7 alkyl, or NR 5 R 6 ; or (e) --SR 8 , wherein R 8 is hydrogen or C 1-7 alkyl, or C 1-7 alkyl substituted with one or more halogen, or OR 4 ; or (f) C 1-7 alkyl, or C 1-7 alkyl substituted with one or more halogen, or OR 4 or NR 5 R 6 ; or (g) R 1 and R 2 are together (i) ═O, or (ii) ═NOR 8 , or (iii) ═S; and R 3 is (h) C 1-7 alkyl or C 1-7 substituted with one or more halogen, OR 4 or NR 5 R 6 ; or (i) aryl, wherein said aryl comprises up to 10 carbon atoms and is an unsubstituted carbocyclic aryl or heterocyclic aryl, which may be selected from the group consisting of phenyl, thienyl, furyl, pyridyl, pyrryl, piperidyl, pyrrolidyl, morpholinyl, or said carbocyclic aryl or heterocyclic aryl is substituted with one or more halogen, or OR 4 , or NR 5 R 6 , or carboxylic acid or lower alkyl esters thereof, or carboxaldehyde or C 1-7 alkyl, or C 1-7 alkyl substituted with one or more halogen, or OR 4 , or NR 5 R 6 or carboxylic acid or lower alkyl esters thereof; or (j) --COR 9 , wherein R 9 is R 7 or a carbocyclic or a heterocyclic radical, e.g. aryl, wherein said carbocyclic or a heterocyclic radical comprises up to 10 carbon atoms and may be selected from the group consisting of phenyl, cyclopentyl, cyclohexyl, thienyl, furyl, pyridyl, pyrryl, piperidyl, pyrrolidyl, morpholinyl or said carbocyclic aryl or heterocyclic aryl radical is substituted with one or more halogen, or OR 4 , or NR 5 R 6 , or C 1-7 or C 1-7 alkyl substituted with one or more halogen, OR 4 or NR 5 R 6 . Preferably, in the novel compounds of the invention R 1 and R 2 , together, represent O; or at least one of R 1 or R 2 is hydrogen and the other is OH, OCOCH 3 , NOH, or H. (That is, the novel compounds of this invention may include an alpha carbonyl or hydroxy, or acetoxy, or hydroxyamino, etc. group at the 5 position on the thiophene ring.) R 3 preferably represents C 1 to C 6 alkyl or phenyl or phenyl substituted with one or more, more preferably one, hydroxy, methoxy, acetoxy, acetoxymethylene, carboxy, hydroxymethyl, formyl, N,N-dimethylaminomethyl fluoro, chloro or bromo radicals. DETAILED DESCRIPTION OF THE INVENTION The novel compounds of the invention may be prepared by the following general reaction scheme: 4-Bromo-2-thiophenecarboxaldehyde is reacted with R 3 Li or R 3 MgX, wherein X is a halogen, e.g., bromo or iodo, in tetrahydrofuran, or any other dipolar, aprotic solvent, e.g. diethylether, dioxane, etc., at a temperature of from about 0° C. to -78° C., to yield an alkoxide of the addition product. This intermediate is reacted with trimethylsilylchloride, at a temperature of from about 0° C. to -78° C., to provide a "protected" alcohol. The protected intermediate is consecutively reacted with n-Butyllithium in tetrahydrofuran at a temperature of about -100° C. to yield the 3-lithio compound. The lithio compound is reacted with SO 2 at a temperature of about -100° C. in THF, or other aprotic solvent, to yield the lithio sulfinate. The lithium sulfinate is reacted with N-chloro succinimide (NCS) at ambient temperatures in dichloromethane to yield the sulfonyl chloride. The sulfonyl chloride is consecutively reacted with NH 4 OH and tetra-n-butyl ammonium fluoride to yield a novel compound of the invention represented by the general formula: ##STR3## I may be oxidized by Jones' reagent to yield a novel compound of the invention represented by the general formula: ##STR4## That is, II represents the alpha carbonyl derivatives of the invention, i.e., wherein R 1 and R 2 together, represent O (oxygen). II may be reacted with H 2 NOH.HCl in pyridine to provide compounds of the invention represented by the general formula: ##STR5## That is, in the compounds represented by Formula III, R 1 and R 2 , together, represent NOH. Alternatively, compounds represented by Formula I may be reacted with acetic anhydride in pyridine to yield compounds of the invention represented by the general formula: ##STR6## That is, in the compounds represented by Formula IV, R 1 represents OCOCH 3 and R 2 represents hydrogen. Of course, other anhydrides may be used, e.g. benzoic anhydride, to provide compounds wherein R 1 represents a radical derived from said other anhydride, e.g. R 1 is OCOC 6 H 5 . An alternative to the above general reaction scheme relies on the Wittig reaction as follows: (Alkyl)triphenylphosphonium bromide is reacted with 4-bromo-2-thiophene carboxaldehyde in THF, in the presence of potassium tertiary butoxide to yield ##STR7## wherein R is an unsaturated alkenyl radical derived from the above alkyl phosphonium bromide. The 2-(alk-1-enyl)-4-bromothiophene of Formula V may be hydrogenated in the presence of Wilkenson's catalyst to yield the saturated derivative. The saturated derivative is consecutively reacted with n-butyl lithium, SO 2 , NCS and NH 4 OH/tetra-n-butyl ammoniumfluoride to yield ##STR8## wherein R 1 =R 2 =H and R 3 is alkyl. Specific compounds within the scope of this invention include: 1-[5-(3-sulfamoyl thienyl)] pentanone oxime 5-(4-hydroxybenzoyl)3-thiophene sulfonamide 5-(3-N,N-dimethylamino-4-hydroxybenzhydrol)-3-thiophene sulfonamide 5-(1-hydroxy-n-pentyl)-3-thiophene sulfonamide 5-(1-hydroxy-n-heptyl)-3-thiophene sulfonamide 5-(4-acetoxymethylbenzhydrol)-3-thiophene sulfonamide 5(4-formylbenzhydrol)-3-thiophene sulfonamide 5-(4-carboxylbenzhydrol)-3-thiophene sulfonamide 5-(benzhydrol)-3-thiophene sulfonamide 5-(4-methoxybenzhydrol)3-thiophene sulfonamide 5-(2-methoxybutyl)-3-thiophene sulfonamide 5-(4-chlorohexyl)-3-thiophene sulfonamide 5-(3-phenylpentyl)-3thiophene sulfonamide 5-(3-methylpentyl)-3-thiophene sulfonamide 5-benzoyl-3-thiophene sulfonamide 5-[benzhydrol]-3-thiophene sulfonamide When administered for the treatment of elevated intraocular pressure of glaucoma, the active compound is most desirably administered topically to the eye, although systemic treatment is also satisfactory. When given systemically, the drug can be given by any route, although the oral route is preferred. In oral administration the drug can be employed in any of the usual dosage forms such as tablets or capsules, either in a contemporaneous delivery or sustained release form. Any number of the usual excipients or tableting aids can likewise be included. The active drug of this invention is most suitably administered in the form of ophthalmic pharmaceutical compositions adapted for topical administration to the eye such as a suspension, ointment, or as a solid insert. Formulations of these compounds may contain from 0.01 to 15% and especially 0.5% to 3% of medicament. Higher dosages as, for example, about 10%, or lower dosage can be employed provided the dose is effective in reducing or controlling elevated intraocular pressure. As a unit dosage from 0.001 to 10.0 mg, preferably 0.005 to 2.0 mg, and especially 0.1 to 1.0 mg of the compound is generally applied to the human eye, generally on a daily basis is single or divided doses so long as the condition being treated exists. The hereinbefore described dosage values are believed accurate for human patients and are based on the known and presently understood pharmacology of the compounds, and the activity of other similar entities in the human eye. As with all medications, dosage requirements are variable and must be individualized on the basis of the disease and the response of the patient. The pharmaceutical preparation which contains the active compound may be conveniently admixed with a non-toxic pharmaceutical organic carrier, or with a non-toxic pharmaceutical inorganic carrier. Typical of pharmaceutically acceptable carriers are, for example, water, mixtures of water and water-miscible solvents such as lower alkanols or aralkanols, vegetable oils, polyalkylene glycols, petroleum based jelly, ethyl cellulose, ethyl oleate, carboxymethylcellulose, polyvinylpyrrolidone, isopropyl myristrate and other conventionally employed acceptable carriers. The pharmaceutical preparation may also contain non-toxic auxiliary substances such as emulsifying, preserving, wetting agents, bodying agents and the like, as for example, polyethylene glycols, antibacterial components such as quaternary ammonium compounds, phenylmercuric salts known to have cold sterilizing properties and which are non-injurious in use, thimerosal, methyl and propyl paraben, benzyl alcohol, buffering ingredients such as sodium chloride, sodium borate, sodium acetate, and other conventional ingredients such as sorbitan monolaurate, polyoxyethylene sorbitan monopalmitylate, dioctyl sodium sulfosuccinate, monothioglycerol, thiosorbitol, ethylenediamine tetracetic acid, and the like. Additionally, suitable ophthalmic vehicles can be used as carrier media for the present purpose including conventional phosphate buffer vehicle systems, isotonic boric acid vehicles, isotonic sodium chloride vehicles, isotonic sodium borate vehicles and the like. The pharmaceutical preparation may also be in the form of a solid insert. While many patients find liquid medication to be entirely satisfactory, other may prefer a solid medicament that is topically applied to the eye, for example, a solid dosage form that is suitable for insertion into the cul-de-sac. To this end the carbonic anhydrase inhibiting agent can be included with a non-bioerodable insert, i.e., one which after dispensing the drug remains essentially intact, or a bioerodable insert, i.e., one that either is soluble in lacrimal fluids, or otherwise disintegrates. For example, one may use a solid water soluble polymer as the carrier for the medicament. The polymer used to form the insert may be any water soluble non-toxic polymer, for example, cellulose derivatives such as methylcellulose, sodium carboxymethyl cellulose, or a hydroxy lower alkyl cellulose such as hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxypropylmethyl cellulose and the like; acrylates such as polyacrylic acid salts, ethyl acrylates, polyacrylamides; natural products such as gelatin, alginates, pectins, tragacanth, karaya, chondrus, agar, acacia; the starch derivatives such as starch acetate, hydroxyethyl starch ethers, hydroxypropyl starch, as well as other synthetic derivatives such as polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl methyl ether, polyethylene oxide, neutralized carbopol and xanthan gum, and mixtures of said polymers. The invention is further illustrated by the following examples which are illustrative of a specific mode of practicing the invention and is not intended as limiting the scope of the appended claims. EXAMPLE 1 2-(n-Hex-1-enyl)-4-bromo thiophene 2.0 grams (10.5 mmols) of (n-pentyl) triphenyl phosphonium bromide was added to 105 ml. of tetrahydrofuran (THF) with stirring. 1.86 gms (15.8 mmol.) of potassium tertiary butoxide was then added to the mixture while stirring at room temperature under an argon atmosphere. After one hour of continued stirring, 2.0 gms (10.5 mmol) of 4-bromo-2-thiophene carboxaldehyde, dissolved in 20 ml of THF, was added to the phosphonium bromide solution. After an additional one hour, the reaction was quenched with water. The organic layer was then separated, washed twice with water and then with brine. After drying over MgSO 4 and filtering, the filtrate was concentrated. The concentrate was flushed through a silica plug and eluted with hexane to yield 2.2 gms of a yellow liquid. This liquid included a mixture of cis and trans isomers of the named compound and had the following NMR spectra: 1 HNMR (CDCl 3 ): 7.12 (s), 6.98 (s), 6.88 (s), 6.42 (app. d), 6.03-6.14 (m), 5.52-5.64 (m), 2.32-2.42 (m), 2.12-2.22 (m), 1.28-1.74 (m), 0.90-0.98 (m). EXAMPLE 2 2-(hexyl)-4-bromo thiophene 2.2 gms (9.0 mmol) of the product of Example 1 were dissolved in 25 ml of ethanol and 0.22 gms of Wilkenson's catalyst were added. (Wilkenson's catalyst is tris(triphenylphosphine) rhodium (I) chloride.) The mixture was stirred at room temperature under atmospheric hydrogen pressure overnight. The reaction product was concentrated and separated by flash chromatography, using hexane, as the eluant, to yield 2.2 gms of a colorless liquid. The NMR spectra of said liquid was as follows: 1 HNMR (CDCl 3 ): 7.01 (s), 6.98 (s), 6.78 (s), 6.71 (s), 6.42 (d, J=15 Hz), 6.09 (d, t, J=8, 15 Hz), 2.77 (t, J=7 Hz), 2.12-2.22 (m), 1.60-1.70 (m), 1.29-1.35 (m), 0.87-0.91 (m). From said spectra it was determined that 2-(n-hex-1-enyl)-4-bromothiophene was still present in the reaction product. The reaction product was again treated with Wilkenson's Catalyst and hydrogen, overnight. The re-treated reaction mixture was passed through a silica gel plug and eluted with hexane to yield 2.1 gms of a clear, colorless liquid having the following NMR spectra: 7.01 (s, 1H), 6.71 (s, 1H), 2.77 (t=7 Hz, 2H), 1.65 (m, 2H), 1.29-1.35 (m, 6H), 0.89 (t, J=7 Hz, 3H). EXAMPLE 3 5-n-Heptyl-3-thiophene sulfonamide 1.93 gms (7.8 mmol) of the bromothiophene of Example 2 were added to 78 ml. of THF and the solution was cooled to -100° C., while under an argon atmosphere. 4.9 ml of a 1.6M solution of n-butyl lithium (n-BuLi) in hexane were added to the cooled solution and stirred at -100° C. under an argon atmosphere. After a few minutes, SO 2 was bubbled into the solution. When the solution became saturated with SO 2 , it was allowed to warm to room temperature and 20 ml. of ethyl ether were then added. After about two and one-half hours, the solution was transferred to a roto-evaporator and concentrated. The resulting concentrate was dissolved in 78 ml of methylene dichloride (CH 2 Cl 2 ) and 1.15 gms (8.6 mmol) of N-chlorosuccinamide (NCS) were added. The resulting mixture was stirred, under argon, at room temperature for two hours. The resulting mixture was filtered and the filtrate was concentrated. The concentrate was dissolved in 50 ml of acetone and 10 ml of concentrate NH 4 OH (aqueous) were added. After 10 minutes, the mixture was diluted with ethyl acetate and washed with water three times and then with a saturated salt solution, i.e. brine. The organic phase was separated, dried over MgSO 4 , filtered and the filtrate concentrated. The concentrate was subjected to flash chromatography utilizing a 3 to 1, by volume, mixture of hexane and ethyl acetate eluant to yield 1.24 gms of a light yellow solid having the following NMR spectra: 1 H NMR (CDCl 3 ): 7.76 (d, J=1.4 Hz, 1H), 7.07 (d, J=1.4 Hz, 1H), 5.21 (bs, 2H), 2.76 (q, J=7.7 Hz, 2H), 1.65 (p, J=7.7 Hz, 2H), 1.28-1.38 (m, 6H), 0.87 (t, J=6.8 Hz, 3H). EXAMPLE 3(a) 5-n-Pentyl-3-thiophene sulfonamide The reactions set forth in Examples 1 through 3 are repeated except that (n-butyl)triphenylphosphine bromide is substituted for (n-pentyl)triphenylphosphine bromide to yield the named compound. EXAMPLE 3(b) 5-(3-methylpentyl)-3-thiophene sulfonamide The reactions set forth in Examples 1 through 3 are repeated except that (2-methylbutyl)triphenylphosphine bromide is substituted for (n-pentyl)triphenylphosphine bromide to yield the named compound. EXAMPLE 3(c) 5-(3-phenylpentyl)-3-thiophene sulfonamide The reactions set forth in Examples 1 through 3 are repeated except that (2-phenylbutyl)triphenylphosphine bromide is substituted for (n-pentyl)triphenylphosphine bromide to yield the named compound. EXAMPLE 3(d) 5-(4-chlorohexyl)-3-thiophene sulfonamide The reactions set forth in Examples 1 through 3 are repeated except that (3-chloropentyl)triphenylphosphine bromide is substituted for (n-pentyl)triphenylphosphine bromide to yield the named compound. EXAMPLE 3(e) 5-(2-methoxybutyl)-3-thiophene sulfonamide The reactions set forth in Examples 1 through 3 are repeated except that (3-methoxypropyl)triphenylphosphine bromide is substituted for (n-pentyl)triphenylphosphine bromide to yield the named compound. EXAMPLE 4 5-[(4-t-butyldimethylsiloxyphenyl)(trimethylsiloxy)methyl]-3-bromothiophene 5.9 gms (0.02 mol) of 4-bromo t-butyldimethylsiloxybenzene were dissolved in 42 ml of dry THF. The solution was cooled to -78° C. while under an argon atmosphere and 13.1 ml (0.02 mol) of a 1.6M solution of n-butyl lithium in hexane were added. After stirring for fifteen minutes under argon the solution was combined over a twenty-five-minute period with a solution of 4.0 gms (0.02 mol) of 4-bromo-2-thiophene carboxaldehyde in 50 ml. of THF at -78° C. The resulting solution was stirred for one hour and fifteen minutes at -78° C. 1.95 ml of trimethylsilylchloride (TMSCI) were added and the solution was allowed to warm to room temperature overnight with stirring. An additional 10 ml of TMSCl were added and the solution was stirred for six hours. The reaction was quenched with water; the organic phase was separated from the brine, dried over MgSO 4 , filtered, concentrated and separated by flash chromatography, utilizing hexane as the eluant. 2.5 gms of a clear colorless liquid were recovered having an NMR spectra of: 1 H NMR (acetone-d 6 ): 7.21 (d, J=8.5 Hz, 2H), 7.11 (d, J=1.5 Hz, 1H), 6.80 (d, J=8.5 Hz, 2H), 6.65 (d, J=1.5 Hz, 1H), 5.84 (s, 1H), 0.99 (s, 3H), 0.21 (s, 6H), 0.10 (s, 9H). EXAMPLE 5 5-(4-hydroxybenzhydrol)3-thiophene sulfonamide 2.34 gms (5.0 mmol) of the bromothiophene, prepared in Example 4, were dissolved in 50 ml of dry THF. The resulting solution is cooled to -78° C. while under an argon atmosphere. 3.1 ml of a 1.6M solution of n-BuLi, in hexane, is added and stirring was continued for a few minutes. SO 2 was bubbled into the solution until the solution was saturated with SO 2 . 20 ml of ethyl ether were added and the solution was allowed to warm to room temperature. After about two hours at room temperature, the solution was concentrated, the residue dissolved in 50 ml of methylene dichloride and 0.73 gms (5.5 mmol) of NCS were added. After about one-half hour, the resulting mixture was filtered, the filtrate concentrated and the concentrate was dissolved in a solution of 5 ml concentrated NH 4 OH (aqueous) and 25 ml of acetone. After one-half hour, the resulting solution is diluted with ethyl acetate, washed with water, three times, and then with brine. The resulting organic phase is separated, dried over MgSO 4 , filtered and the filtrate concentrated. The concentrate was subjected to flash chromatography utilizing a 3:1 mixture of hexane and ethyl acetate, as the eluant, to yield 1.41 gms of a light yellow oil having the following NMR spectra: 1 H NMR (acetone-d 6 ): 7.88 (s, 1H), 7.33 (d, J=9 Hz, 2H), 7.10 (s, 1H), 6.88 (d, J=9 Hz, 2H), 6.55 (bs, 2H), 6.07 (s, 1H), 0.97 (s, 9H), 0.20 (s, 6H), 0.07 (s, 9H). 0.52 gms (1.1 mmol.) of the product light yellow oil was dissolved in 11 ml of THF and 2.3 ml of a 1.0M solution of tetra-n-butyl ammonium fluoride (TBAF) in THF is added. After one-half hour, the reaction was quenched with water and extracted with ethyl acetate. The organic layer was separated, washed three times with water and then with brine. The organic phase was separated, dried over MgSO 4 , filtered and the filtrate concentrated. The concentrate was subjected to flash chromatography, utilizing the above hexane/ethyl acetate mixture to yield 0.26 gms of a white foam having the following NMR spectra: 1 H NMR (acetone-d 6 ): 8.43 (bs, 1H), 7.88 (s, 1H), 7.28 (d, J=9 Hz, 2H), 7.05 (s, 1H), 6.82 (d, J=9 Hz, 2H), 6.57 (bs, 2H), 5.95 (s, 1H), 5.32 (bs, 1H). EXAMPLE 5(a) 5-(4-methoxybenzhydrol)-3-thiophene sulfonamide The reactions set forth in Examples 4 and 5 are repeated except that 4 -methoxybromobenzene is substituted for 4-bromo t-butyldimethyl-siloxy-benzene to yield the named compound which has the following NMR spectra: 1 H NMR (acetone-d 6 ): 7.88 (d, J=1.5 Hz, 1H), 7.38 (d, J=8.6 Hz, 2H), 7.07 (m, 1H), 6.92 (d, J=8.6 Hz, 2H), 6.54 (bs, 2H), 5.99 (d, J=4.3 Hz, 1H), 5.34 (d, J=4.3 Hz, 1H), 3.78 (s, 3H). EXAMPLE 5(b) 5-(benzhydrol)-3-thiophene sulfonamide The reactions set forth in Examples 4 and 5 are repeated except that bromobenzene is substituted for 4-bromo t-butyldimethylsiloxybenzene to yield the named compound. This compound may be subsequently reacted with acetic anhdyride in the presence of pyridine, as described above, to yield the acylated derivative, i.e. 5-[(phenyl)(acetoxy)methyl]-3-thiophene sulfonamide, having the following NMR spectra: 1 H NMR (acetone-d 6 ): 7.90 (s, 1H), 7.30-7.50 (m, 5H), 7.10 (s, 1H), 6.55 (bs, 2H), 6.05 (d, J=4.3 Hz, 1H), 5.46 (d, J=4.3 Hz, 1H). EXAMPLE 5(c) 5-(1-hydroxy-n-heptyl)-3-thiophene sulfonamide The reactions set forth in Examples 4 and 5 are repeated except that 1-bromohexane is substituted for 4-bromo t-butyldiimethylsiloxybenzene to yield the named compound, having the following NMR spectra: 1 H NMR (CDCl 3 ): 7.88 (s, 1H), 7.24 (s, 1H), 5.06 (bs, 2H), 4.88-4.89 (m, 1H), 2.43-2.45 (m, 1H), 1.79-1.81 (m, 2H), 1.25-1.31 (m, 8H), 0.86-0.88 (m, 3H). EXAMPLE 5(d) 5-(1-hydroxy-n-pentyl)-3-thiophene sulfonamide The reactions set forth in Examples 4 and 5 are repeated except that 1-bromobutane is substituted for 4-bromo t-butyldimethylsiloxybenzene to yield the named compound, having the following NMR spectra: 1 H NMR (CDCl 3 ): 7.82 (s, 1H), 7.20 (s, 1H), 5.35 (bs, 2H), 4.80 (t, J=4.5 Hz, 1H), 1.70-2.88 (m, 2H), 1.24-1.48 (m, 4H), 0.88 (t, J=4.5 Hz, 3H). EXAMPLE 5(e) 5-(3-hydroxybenzhydrol)-3-thiophene sulfonamide The reactions set forth in Examples 4 and 5 are repeated except that 3-bromo t-butyldimethylsiloxy is substituted for 4-bromo t-butyldi-methylsiloxybenzene to yield the named compound, having the following NMR spectra: 1 H NMR (acetone-d 6 ): 8.40 (bs, 1H), 7.89 (d, J=1.5 Hz, 1H), 7.18 (t, J=7.7 Hz, 1H), 7.11 (d, J=1.5 Hz, 1H), 6.92-6.97 (m, 2H), 6.75-6.78(m, 1H), 6.56 (bs, 2H), 5.97 (s, 1H), 5.40 (bs, 1H). EXAMPLE 6 5-(4-hydroxybenzoyl)-3-thiophene sulfonamide 0.10 gms (0.35 mmol) of 5-(4-hydroxybenzhydrol) 3-thiphene sulfonamide, as prepared in Example 5, were dissolved in 5 ml of acetone and to this solution 0.13 ml (0.35 mmol) of a 2.67M solution of Jones' Reagent were added. (Jones' Reagent is aqueous chromic acid.) The resulting mixture was stirred for about forty minutes at room temperature and then quenched with isopropyl alcohol. The resulting solution was diluted with ethyl acetate, washed three times with water and then with brine. The organic layer was separated, dried over MgSO 4 , filtered and the filtrate concentrated. The concentrate was subjected to flash chromatography, utilizing a 1:1 mixture of hexane and ethyl acetate, as the eluant, to yield 78 mg of a clear colorless oil having the following NMR spectra: 1 H NMR (acetone-d 6 ): 9.45 (bs, 1H), 8.43 (d, J=1.3 Hz, 1H), 7.95 (d, J=1.3 Hz, 1H), 7.89 (d, J=9 Hz, 2H), 7.04 (d, J=9 Hz, 2H), 6.81 (bs, 2H). EXAMPLES 6(a)-(j) The compounds of Examples 5(a)-(j) are converted into the corresponding alpha carbonyl derivatives by the method of Example 6. The compounds were identified by the NMR spectra given below. EXAMPLE 6(a) 5-(4-methoxybenzoyl)-3-thiophene sulfonamide 1 H NMR (acetone-d 6 ): 8.43 (s, 1H), 7.92-7.95 (m, 3H), 7.12 (d, J=9.0 Hz, 2H), 6.77 (bs, 2H), 3.93 (s, 3H). EXAMPLE 6(b) 5-benzoyl-3-thiophene sulfonamide 1 H NMR (acetone-d 6 ): 8.48 (s, 1H), 7.90-7.95 (m, 3H), 7.60-7.75 (m, 3H), 6.80 (2H). EXAMPLE 6(c) 5-(1-heptanoyl)-3-thiophene sulfonamide 1 H NMR (CDCl 3 ): 8.21 (s, 1H), 7.94 (s, 1H), 5.01 (bs, 2H), 2.89 (t, J=7.3 Hz, 2H), 1.73 (p, 7.2 Hz, 2H), 1.30-1.34 (m, 6H), 0.88 (t, J=8.3 Hz, 3H). EXAMPLE 6(d) 5-(1-pentanoyl)-3-thiophene sulfonamide 1 H NMR (CDCl 3 ): 8.22 (s, 1H), 7.96 (s, 1H), 5.10 (bs, 2H), 2.90 (t, J=7.5 Hz, 2H), 1.73 (p, J=7.5 Hz, 2H), 1.40 (sex., J=7.5 Hz, 2H), 0.95 (t, J=7.5 Hz, 3H). EXAMPLE 6(e) 5-(3-hydroxybenzoyl)-3-thiophene sulfonamide 1 H NMR (acetone-d 6 ): 8.46 (d, J=1.3 Hz, 1H), 7.93 (d, J=1.4 Hz, 1H), 7.32-7.46 (m, 3H), 7.15-7.19 (m, 1H), 6.86 (bs, 2H). Examples 6(f) to (j) were prepared by a process analogous to the preparation of Examples 6(a) to (e) with the appropriate bromo reactant substituted for the 4-bromotrimethylsiloxybenzene. EXAMPLE 6(f) 5-(4-butylbenzoyl)-3-thiophene sulfonamide 1 H NMR (acetone-d 6 ): 8.45 (d, J=1.4 Hz, 1H), 7.93 (d, J=1.4 Hz, 1H), 7.85 (d, J=8.2 Hz, 2H), 7.45 (d, J=8.2 Hz, 2H), 6.78 (bs, 2H), 2.74 (t, J=7.5 Hz, 2H), 1.60-1.68 (m, 2H),. 1.38 (sex., J=7.8 Hz, 2H), 0.93 (t, J=7.3 Hz, 3H). EXAMPLE 6(g) 5-(3-trifluoromethylbenzoyl)-3-thiophene sulfonamide 1 H NMR (acetone-d 6 ): 8.52 (d, J=1.4 Hz, 1H), 8.22 (d, J=7.9 Hz, 1H), 8.17 (s, 1H), 8.06 (d, J=8.3 Hz, 1H), 7.95 (d, J=1.4 Hz, 1H), 7.88 (t, J=7.8 Hz, 1H), 6.78 (bs, 2H). EXAMPLE 6(h) 5-(2-fluorobenzoyl)-3-thiophene sulfonamide 1 H NMR (acetone-d 6 ): 8.50 (d, J=1.2 Hz, 1H), 7.79 (t, J=1.5 Hz, 1H), 7.68-7.73 (m, 2H), 7.34-7.44 (m, 2H), 6.80 (bs, 2H). EXAMPLE 6(i) 5-(3-fluorobenzoyl)-3-thiophene sulfonamide 1 H NMR (acetone-d 6 ): 8.49 (s, 1H), 7.95 (s, 1H), 7.60-7.77 (m, 3H), 7.47-7.53 (m, 1H), 6.79 (bs, 2H). EXAMPLE 6(j) 5-(3.5-difluorobenzoyl)-3-thiophene sulfonamide 1 H NMR (acetone-d 6 ): 8.51 (s, 1H), 7.99 (s, 1H), 7.49-7.56 (m, 2H), 7.37-7.44 (m, 1H), 6.79 (bs, 2H). EXAMPLE 7 5-(4-hydroxy-3-(N,N-dimethylaminomethyl)benzoyl)-3-thiophene sulfonamide 5-(4-hydroxy-3,5-(bis-N,N-dimethylaminomethyl)benzoyl)-3-thiophene sulfonamide 0.25 g (0.88 mmol) of 5-(4-hydroxybenzoyl)-3-thiophene sulfonamide, 0.21 mL (2.6 mmol)of aqueous formaldehyde (37%) and 0.89 mL (7.9 mmol)of aqueous dimethylamine (40%) were added to 3 mL of ethanol. The solution was heated at reflux for 15 1/2 h and then cool to room temperature. Solvent was removed under vacuum and the crude product subjected to flash chromatography. Utilizing 5:1 chloroform/methanol as the eludent 49 mg of 5-(4-hydroxy-3-(N,N-dimethylaminomethyl)benzoyl)-3-thiophene sulfonamide was recovered as a yellow color solid. 1 H NMR (acetone-d 6 ): 8.39 (d, J=1.4 Hz, 1H), 7.92 (d, J=1.4 Hz, 1H), 7.81 (dd, J=8.5, 2.3 Hz, 1H), 7.67 (d, J=2.3 Hz, 1H), 6.85 (d, J=8.5 Hz, 1H), 3.82 (s, 2H), 2.38 (s, 6H). The eluant was switched over to 2:1 methanol/chloroform (with 5% triethylamine) and 0.18 g of 5-(4-hydroxy-3,5-(bis-N,N-dimethylamino-methyl)benzoyl)-3-thiophene sulfonamide was recovered as a yellow color solid. 1 H NMR (acetone-d 6 ): 8.39 (d, J=1.4 Hz, 1H), 7.93 (d, J=1.4 Hz, 1H), 7.75 (s, 2H), 3.66 (s, 4H), 2.32(s, 12H). EXAMPLE 8 4-bromo-2-[tetrahydropyronyl) (4-t-butyldimethylsiloxymethylphenyl)methyl] thiophene 6.5 g (22 mmol) of 4-bromobenzyl alcohol, t-butyldimethylsilyl ether was added to 40 mL of THF. The solution was cool to -78° C. 15.3 mL (22 mmol) of a 1.42M n-BuLi solution was added. The solution was transferred via cannula to 4.2 g (22 mmol) of 4-bromo-2-thiophene carboxaldehyde in 70 mL THF at -78° C. Reaction was stirred at -78° C. for 30 min before quenching with 5 mL of saturated NH 4 Cl. The reaction was diluted with ethyl acetate and washed with water (3×) followed with brine. Solution was dried over MgSO 4 and the solvent removed under vacuum. The product, 10 mL (o.11 mol) of DHP and a catalytic amount of TsOH were added to 88 mL of dichloromethane. The reaction was stirred at rt for 18 1/2 h. The reaction was washed with water (3×) followed with brine. The solution was dried over MgSO 4 and the solvent removed under vacuum. Flash chromatography utilizing 20:1 hexane/ethyl ether as the eluant recovered 9.3 g of the product as a light yellow color oil. 1 H NMR (CDCl 3 ): mixture of diastereomers; 7.27-7.40 (m), 7.12-7.18 (m), 6.90 (s), 6.58 (s), 5.95 (s), 5.90 (s), 4.84-4.88 (m), 4.75 (s), 4.72 (s), 4.62-4.66 (m), 3.96-4.05 (m), 3.74-3.82 (m), 3.48-3.62 (m), 1.48-2.02 (m), 0.94 (s), 0.93 (s), 0.12 (s), 0.10 (s). EXAMPLE 9 5-[(tetrahydropyranyl)(4-t-butyldimethylsiloxymethylphenyl)methyl]-3-thiophene sulfonamide 8.8 g (18 mmol) of the product obtained in Example #8 was added to 180 mL of THF. The solution was cool to -100° C. 12.7 mL (18 mmol) of a 1.42M n-BuLi solution was added dropwise. After a few minutes SO 2 was passed through the reaction flask until the solution became saturated. 30 mL of ethyl ether was added and the liquid nitrogen/ethyl ether bath removed. After 2 h the solvent was removed under vacuum. The crude product and 2.6 g (19.8 mmol) NCS were added to 180 mL of dichloromethane. After stirring at rt for 11/2 h the mixture was filtered and the filtrate concentrated. The crude product was added to 30 mL of concentrated ammonium hydroxide in 180 mL of acetone. Upon stirring for 31/2 h the solution was dilutd with ethyl acetate and washed with water (3×) followed with brine. The solution was dried over MgSO 4 and the solvent removed under vacuum. Flash chromatography utilizing 2:1 hexane/ethyl acetate recovered 2.9 g of the product as a yellow color oil. 1 H NMR (CDCl 3 ): mixture of diastereomers; 7.96 (s), 7.94 (s), 7.49-7.34 (m), 7.01 (s), 6.07 (s), 6.01 (s), 4.83-4.86 (m), 4.78 (s), 4.60-4.64 (m), 3.90-3.99 (m), 3.68-3.77 (m), 3.43-3.58 (m), 1.43-1.98 (m), 0.96 (s), 0.15 (s), 0.13 (s). EXAMPLE 10 5-(4-hydroxymethylbenzhydrol)-3-thiophene sulfonamide 0.36 g (0.72 mmol) of the product from Example #9 and a catalytic amount of TsOH were added to 10 mL of methanol. After 2 h of stirring at rt the solution was diluted with ethyl acetate and washed with water (3×) followed with brine. The solution was dried over MgSO 4 and the solvent removed under vacuum. Flash chromatography utilizing 2:1 ethyl acetate/hexane as the eluant recovered 87 mg of 5-(4-hydroxymethylbenzhydrol)-3-thiophene sulfonamide as a clear colorless oil. 1 H NMR (acetone-d 6 ): 7.88 (d, J=1.4 Hz, 1H), 7.44 (d, J=7.5 Hz, 2H), 7.35 (d, J=7.5 Hz, 2H), 7.08 (d, J=1.4 Hz, 1H), 6.54 (bs, 2H), 6.04 (d, J=4.3 Hz, 1H), 5.42 (d, J=4.3 Hz, 1H), 4.62 (d, J=5.7 Hz, 2H), 4.19 (t, J=5.8 Hz, 1H). EXAMPLE 11 5-(4-carboxybenzoyl)-3-thiophene sulfonamide 0.53 g (1.8 mmol) of 5-(4-hydroxymethylbenzhydrol)-3-thiophene sulfonamide was added to 8.8 mL of acetone. The solution was cool to 0° C. and 1.35 mL (3.7 mmol) of Jone's reagent was added. After 15 min the solvent was removed under vacuum and the mixture filtered. The solid was washed with water. Flash chromatography utiling 20% methanol/chloroform as the eluant recovered 0.48 g of 5-(4-carboxybenzoyl)-3-thiophene sulfonamide as a white solid. 1 H NMR (acetone-d 6 ): 8.51 (d, J=1.4 Hz, 1H), 8.23 (d, J=8.3 Hz, 2H), 8.01 (d, J=8.3 Hz, 2H), 7.94 (d, J=1.4 Hz, 1H),6.79 (bs, 2H). EXAMPLE 11(a) 5-(3-carboxylbenzoyl)-3-thiophene sulfonamide 1 H NMR (acetone-d 6 ): 8.51 (d, J=1.4 Hz, 1H), 8.50 (s, 1H), 8.34 (d, t, J=7.8, 1.3 Hz, 1H), 8.16 (d, t, J=7.8, 1.3 Hz, 1H), 7.96 (d, J=1.3 Hz, 1H), 7.77 (t, J=7.8 Hz, 1H), 6.81 (bs, 2H). EXAMPLE 12 5-[(tetrahydropyranyl)(4-hydroxymethylphenyl)methyl]-3-thiphene sulfonamide 0.45 g (0.91 mmol) of the product from Example #9 was added to 10 mL of THF. 1.0 mL (1.0 mmol) of a 1M tetra-n-butylammonium fluoride solution was added. After stirring at rt for 1 h the solution was diluted with water and extracted with ethyl acetate. The organic phase was washed with water (3×) followed with brine. The solution was dried over MgSO 4 and the solvent removed under vacuum. Flash chromatography utilizing 1:1 hexane/ethyl acetate as the eluent recovered 0.33 g of the product as a clear colorless oil. 1 H NMR (acetone-d 6 ): mixture of diastereomers; 7.97 (s), 7.95 (s), 7.32-7.48 (s), 6.97 (s), 6.60 (bs), 6.55 (bs), 6.05 (s), 5.98 (s), 4.82-4.85 (m), 4.58-4.68 (m), 4.17-4.28 (m), 3.90-3.97 (m), 3.68-3.75 (m), 3.40-3.56 (m), 1.44-1.98 (m). EXAMPLE 13 5-(4-acetoxymethylbenzhydrol)-3-thiophene sulfonamide 0.74 g (1.9 mmol) of the product from Example #12, 0.23 mL (2.9 mmol) of pyridine and 0.23 mL (2.9 mmol) of acetic anhydride were added to 19 mL of dichloromethane. After stirring at rt for 15 h the solution was diluted with ethyl acetate and washed with water (3×) followed with brine. The solution was dried over MgSO 4 and the solvent removed under vacuum. The 0.60 g of the crude product and a catalytic amount of TsOH were added to 14 mL of methanol. After stirring at rt for 31/2 h the solution was diluted with water and extracted with ethyl acetate. The organic phase was washed with water (2×) followed with brine. The solution was dried over MgSO 4 and the solvent removed under vacuum. Flash chromatography utilizing 1:1 hexane/ethyl acetate as the eluant recovered 0.37 g of 5-(4-acetoxymethyl-benzhydrol)-3-thiophene sulfonamide as a clear colorless oil. 1 H NMR (acetone-d 6 ): 7.90 (s, 1H), 7.48 (d, J=7.5 Hz, 2H), 7.37 (d, J=7.5 Hz, 2H), 7.12 (s, 1H), 6.55 (bs, 2H), 6.08 (s, 1H), 5.50 (bs, 1H), 5.10 (s, 2H), 2.08 (s, 3H). EXAMPLE 14 5-(4-acetoxymethylbenzoyl)-3-thiophene sulfonamide 0.20 g (0.6 mmol) of 5-(4-acetoxymethylbenzhydrol)-3-thiophene sulfonamide was added to 6 mL of acetone. 0.22 mL (0.6 mmol) of a 2.67M TBAF solution was added. After stirring at rt for 15 min the reaction was quenched with isopropyl alcohol. The mixture was diluted with water and extracted with ethyl acetate. The organic phase was washed with water (3×) followed with brine. The solution was dried over MgSO 4 and the solvent removed under vacuum. Recrystallization from ethyl acetate/hexane afforded 0.17 g of 5-(4-acetoxymethylbenzoyl)-3-thiophene sulfonamide as white crystals. 1 H NMR (acetone-d 6 ): 8.47 (d, J=1.4 Hz, 1H), 7.93 (s, 1H), 7.92 (d, J=8.3 Hz, 2H), 7.62 (d, J=8.3 Hz, 2H, 6.80 (bs, 2H), 5.22 (s, 2H), 2.10 (s, 3H). EXAMPLE 15 5-(4-hydroxymethylbenzoyl)-3-thiophene sulfonamide 14 mg (41.3 mmol) of 5-(4-acetoxymethylbenzoyl)-3-thiophene sulfonamide and 9 mg (61.8 mmol) of K 2 CO 3 were added to 3 mL of methanol. After stirring at rt for 11 h the solution was diluted with ethyl acetate and washed with 1N HCl followed with water (2×) and brine. The solvent was removed under vacuum to afford 12.5 mg of 5-(4-hydroxymethylbenzoyl)-3-thiophene sulfonamide as a white solid. 1 H NMR(acetone-d 6 ): 8.46 (d, J=1.4 Hz, 1H), 7.93 (d, J=1.4 Hz, 1H), 7.89 (d, J=8.3 Hz, 2H), 7.59 (d, J=7.9 Hz, 2H), 6.79 (bs, 2H), 4.77 (d, J=5.4 Hz, 2H), 4.51 (t, J=5.7 Hz, 1H). EXAMPLE 16 5-(4-formylbenzoyl)-3-thiophene sulfonamide 30 mg (0.1 mmol) of 5-(4-hydroxymethylbenzoyl)-3-thiophene sulfonamide and 300 mg of MnO2 were added to 5 mL of THF. After stirring at rt for 30 min the mixture was filtered through a bed of celite and eluted with ethyl acetate. The filtrate was concentrated and the crude product subjected to flash chromatography utilizing 1:1 ethyl acetate/hexane as the eluent to recover 16 mg of 5-(4-formylbenzoyl)-3-thiophene sulfonamide as a yellow solid. 1 H NMR(acetone-d 6 ): 10.21 (s, 1H), 8.52 (d, J=1.3 Hz, 1H), 8.12 (q, J=9.7 Hz, 4H), 7.94 (d, J=1.3 Hz, 1H), 6.79 (bs, 2H). EXAMPLE 16(a) 5-(3-formylbenzoyl)-3-thiophene sulfonamide 1 H NMR(acetone-d6): 10.18 (s, 1H), 8.52 (d, J=1.3 Hz, 1H), 8.14 (s, 1H), 8.23 (d, t, J=1.4, 8.0 Hz, 2H), 7.97 (d, J=1.4 Hz, 1H), 7.85 (t, J=8.0 Hz, 1H), 6.80 (bs, 2H). EXAMPLE 17 5-(4-formylbenzhydrol)-3-thiophene sulfonamide 0.12 g (0.32 mmol) of the product from Example #12, 4A molecular sieves and 56 mg (0.48 mmol) of NMO were added to 6 mL of dichloromethane. After stirring at rt for 15 min 5.6 mg (0.016 mmol) of TPAP was added. After 4 h at rt the mixture was filtered through a plug of celite and eluted with ethyl acetate. The filtrate was concentrated and the crude product subjected to flash chromatography utilizing 1:1 ethyl acetate/hexane as eluant to recover 42 mg of the desired product and 41 mg of starting material. 63 mg (0.17 mmol) of the product and a catalytic amount of TsOH were added to 5 mL of methanol. After 4 h at rt the solution was diluted with ethyl acetate and washed with saturated NaHCO 3 followed with water (3×) and brine. The solution was dried over MgSO 4 and the solvent removed under vacuum to afford 47 mg of 5-(4-formylbenzhydrol)-3-thiophene sulfonamide as a clear colorless oil. 1 H NMR(acetone-d 6 ): 10.04 (s, 1H), 7.94 (d, J=8.3 Hz, 2H), 7.93 (s, 1H), 7.73 (d, J=8.3 Hz, 2H), 7.18 (s, 1H), 6.58 (bs, 2H), 6.20 (d, J=4 Hz, 1H), 5.77 (d, J=4 Hz, 1H). EXAMPLE 18 5-[(methoxy)(3-trifluoromethylphenyl)methyl]-3-thiophene sulfonamide 0.20 g (0.6 mmol) of 5-(3-trifluoromethylbenzhydrol)-3-thiophene sulfonamide and 0.11 g (0.6 mmol) of TsOH were added to 10 mL of methanol. The solution was heated at reflux for 12 h. The solvent was removed under vacuum and the crude product subjected to flash chromatography utilizing 2:1 hexane/ethyl acetate as the eluant to recover 0.16 g of 5-[(methoxy)(3-trifluoromethylphenyl)methyl]-3-thiophene sulfonamide as a white solid. 1 H NMR (acetone-d 6 ): 7.99 (d, J=1.5 Hz, 1H), 7.66-7.80 (m, 4H), 7.23-7.24 (m, 1H), 6.59 (bs, 2H), 5.76 (s, 1H), 3.41 (s, 3H). EXAMPLE 18(a) 5-[(methoxy)(4-hydroxymethylphenyl)]methyl-3-thiophene sulfonamide 1 H NMR (acetone-d 6 ): 7.94 (d, J=1.1 Hz, 1H), 7.39 (s, 4H), 7.08 (d, J=1.1 Hz, 1H), 6.56 (bs, 2H), 5.56 (s, 1H), 4.64 (d, J=5.9 Hz, 2H), 4.24 (t, J=5.9 Hz, 1H), 3.35 (s, 3H). EXAMPLE 19 5-(1-pentanoyl)-3-thiophene sulfonamide, oxime 0.10 gms (0.4 mmol) of 5-(1-pentanoyl)-3-thiophene sulfonamide and 0.28 gms (4 mmol) of NH 2 OH.HCl were dissolved in 5 ml of pyridine. The reaction vessel was sealed and heated at 60° C. overnight. The reaction solution was cooled to room temperature, diluted with ethyl acetate, washed three times with water and finally with brine. The organic phase was separated, dried over MgSO 4 , filtered and concentrated. Thin liquid chromatography showed that the starting compounds were present. The concentrate was redissolved in 5 ml of pyridine, 0.25 gms of NH 2 OH.HCl were added and the reaction vessel was sealed and heated at 60° C. overnight. The resulting reaction solution was cooled to room temperature, extracted with ethyl acetate, washed with water and brine as described above. After drying with MgSO 4 and filtering, the organic phase was concentrated and subjected to flash chromatography, utilizing a 2 to 1 mixture of hexane and ethyl acetate, as the eluant, to yield 78 mgs. of a white solid having the following NMR spectra: 1 H NMR (acetone-d 6 ): mixture of Isomers: 11.11 (bs), 10.50 (bs), 8.16 (s), 7.92 (s), 7.78 (s), 7.55 (s), 6.64 (bs), 2.68-2.80 (m), 1.35-1.67 (m), 0.89-0.95 (m). EXAMPLES 19(a)-(b) The compounds of Examples 6(a) and (b) are converted into the corresponding oxime derivatives by the method of Example 19. EXAMPLE 19(a) 5-(4-methoxybenzoyl)-3-thiophene sulfonamide, oxime 1 H NMR (acetone-d 6 ): 11.55 (s), 10.58 (s), 8.22 (d, J=1.4 Hz), 7.96 (d, J=1.4 Hz), 7.40-7.47 (m), 7.00-7.07 (m), 6.61-6.64 (m), 3.87 (s), 3.86 (s). EXAMPLE 19(b) 5-benzoyl-3-thiophene sulfonamide, oxime 1 H NMR (acetone-d 6 ): mixture of Isomers: 11.69 (bs), 10.65 (bs), 8.24 (d, J=1.4 Hz), 7.98 (d, J=1.4 Hz), 7.37-7.59 (m), 7.02 (d, J=1.4 Hz), 6.58-6.64 (m). EXAMPLE 20 5-(4-ethoxycarbonylbenzoyl)-3-thiophene sulfonamide 0.1 g (0.32 mmol) of 5-(4-carboxylbenzoyl)-3-thiophene sulfonamide was added to 0.19 g (1.13 mmol) of N,N'-diisopropyl-O-ethyl isourea 1.6 mL of THF. Solution was heated at 50° C. for 2 h. An additional 0.19 g of the isourea was added and the reaction stirred at 50° C. for 48 h. The mixture was filtered through a plug of celite and the filtrate collected and concentrated. Flash chromatography (35% ethyl acetate/hexane) recovered 80 mg of 5-(4-ethoxycarbonylbenzoyl)-3-thiophene sulfonamide as a white color solid. 1 H NMR (acetone-d 6 ): 8.50 (d, J=1.4 Hz, 1H), 8.20 (d, J=8 Hz, 2H), 8.10 (d, J=8 Hz, 2H), 7.92 (d, J=1.4 Hz, 1H), 6.80 (bs, 2H), 4.40 (q, J=7 Hz, 2H), 1.39 (t, J=7 Hz, 3H). EXAMPLE 20(a) 5-(3-butoxycarbonylbenzoyl)-3-thiophene sulfonamide 8.50 (d, J=1.4 Hz, 1H), 8.43 (m, 1H), 8.25 (m, 1H), 8.12 (m 1H), 7.94 (d, J=1.4 Hz, 1H), 7.74 (m, 1H), 6.80 (bs, 2H), 1.60 (s, 9H). EXAMPLE 20(b) 5-(4-(2-N,N-dimethylamino-1-ethoxy)carbonylbenzoyl)-3-thiophene sulfonamide 1 H NMR (CD 3 OD): 8.47 (d, J=1.4 Hz, 1H), 8.29 (d, J=8.5 Hz, 2H), 8.00 (d, J=8.5 Hz, 2H), 7.89 (d, J=1.4 Hz, 1H), 4.73 (t, J=5 Hz, 2H), 3.65 (t, J=5 Hz, 2H), 3.03 (s, 6H). EXAMPLE 20(c) 5-(4-t-butoxycarbonylbenzoyl)-3-thiophene sulfonamide 1 H NMR (acetone-d 6 ): 8.50 (d, J=1.4 Hz, 1H), 8.16 (d, J=8.5 Hz, 2H), 8.00 (d, J=8.5 Hz, 2H), 7.93 (d, J=1.4 Hz, 1H), 6.79 (bs, 2H), 1.61 (s, 9H). EXAMPLE 21 5-(4-acetoxybenzoyl)-3-thiophene sulfonamide 58 mg (0.20 mmol) of 5-(4-hydroxybenzoyl)-3-thiophene sulfonamide, 81 mL (1.0 mmol) of pyridine and 94 mL (1.0 mmol) of acetic anhydride were added to 4 mL of THF. The reaction was stirred at rt for 1 1/4 h and then diluted with ethyl acetate. The organic phase was washed with water (2×) followed with brine. The solution was dried over MgSO 4 and the solvent removed under vacuum. Flash chromatography utilizing 1:1 hexane/ethyl acetate as the eluant recovered 51 mg of 5-(4-acetoxybenzoyl)-3-thiophene sulfonamide as tan color crystals. 1 H NMR (acetone-d 6 ): 8.47 (d, J=1.3 Hz, 1H), 7.98 (d, J=8.6 Hz, 2H), 7.96 (d, J=1.3 Hz, 1H), 7.37 (d, J=8.6 Hz, 2H), 6.78 (bs, 2H), 2.32 (s, 3H). EXAMPLE 21(a) 5-(3-acetoxybenzoyl)-3-thiophene sulfonamide 1 H NMR (acetone-d 6 ): 8.22 (d, J=1.3 Hz, 1H), 7.69 (d, J=1.3 Hz, 1H), 7.53 (d,d, J=7.8, 1.3 Hz, 1H), 7.37 (t, J=7.8 Hz, 1H), 7.39 (s, 1H), 7.18-7.22 (m, 1H), 6.50 (bs, 2H), 2.04 (s, 3H). EXAMPLE 22 5-(4-propionoxybenzoyl)-3-thiophene sulfonamide 0.10 g (0.35 mmol) of 5-(4-hydroxybenzoyl)-3-thiophene sulfonamide, 85 mL (1.05 mmol) of pyridine, 26 mL (0.35 mmol) of propionic acid and 70 mg (0.37 mmol) of EDCI were added to 3.5 mL of THF. The reaction was stirred at rt for 46 h. The solution was diluted with ethyl acetate and washed with water (3×) followed with brine. The solution was dried over MgSO4 and the solvent removed under vacuum. Flash chromatography utilizing 1:1 ethyl acetate/hexane recovered 77 mg of 5-(4-propionoxybenzoyl)-3-thiophene sulfonamide as a clear colorless oil. 1 H NMR (acetone-d 6 ): 8.47 (s, 1H), 7.99 (d, J=8.7 Hz, 2H), 7.95 (s, 1H), 6.79 (bs, 2H), 2.67 (q, J=7.4 Hz, 2H), 1.21 (t, J=7.4 Hz, 3H). EXAMPLE 22(a) 5-(3-benzoxybenzoyl)-3-thiophene sulfonamide 1 H NMR (acetone-d 6 ): 8.50 (d, J=1.4 Hz, 1H), 8.21 (d, J=7.2 Hz, 2H), 8.00 (d, J=1.4 Hz, 1H), 7.59-7.88 (m, 7H), 6.78 (bs, 2H). The compounds of the invention were assayed for biological activity as follows: Carbonic anhydrase activity was assayed according to the micromethod of Maren (J. Pharmacol. Exptl. Therap., 130, 26-29, 1960). All solutions and reagents were maintained at 0°-4° C. The final assay mixture contained 16 mM phenol red, added enzyme and 62.5 mM sodium carbonate/bicarbonate. Its volume was kept constant at 0.8 mL. The time required for the added enzyme to lower the pH of CO 2 -saturated carbonate/bicarbonate buffer from pH 9.9 to 6.8 was measured using the color change of phenol red as endpoint. T 1 is the time recorded for the reaction containing no enzyme. T 2 is the time recorded for the reaction containing pure CA11 enzyme from human erythrocyte, or an unknown amount in a sample. Enzyme activities (unit) were calculated using the formula: Unit/ug=(T.sub.1 -T.sub.2)/(T.sub.2 *ug protein used in assay) IC50 of a carbonic anhydrase inhibitor is the concentration that lowers the enzyme activity to half. The results of this assay are reported in Table 1, below. ______________________________________Structures IC50nM______________________________________5-(4-acetoxybenzoyl)-3-thiophene sulfonamide 12 nM5-(4-hydroxy-3-(N,N-dimethylaminomethyl) 30 nMbenzoyl)-3-thiophene sulfonamide5-(4-hydroxy-3,5-(bis-N,N-dimethylaminomethyl) 155 nMbenzoyl)-3-thiophene sulfonamide5-(hydroxymethylbenzoyl)-3-thiophene sulfonamide 17 nM5-(4-propionoxybenzoyl)-3-thiophene sulfonamide 9 nM5-(3-hydroxybenzoyl)-3-thiophene sulfonamide 6.7 nM5-(3-carboxybenzoyl)-3-thiophene sulfonamide 11, 14 nM5-(3-formylbenzoyl)-3-thiophene sulfonamide 7.3 nM5-(4-butylbenzoyl)-3-thiophene sulfonamide 8.7 nM5-(3-trifluoromethylbenzoyl)-3-thiophene sulfonamide 8.3 nM5-(2-N,N-dimethylamino-1-ethoxy)carbonylbenzoyl)- 25 nM3-thiophene sulfonamide5-(3-butoxycarbonylbenzoyl)-3-thiophene sulfonamide 25 nM5-(4-acetoxybenzoyl)-3-thiophene sulfonamide 3.6 nM[5-(3-sulfonamidothienyl)][2-pyridyl] ketone 19 nM5-(4-ethoxycarbonylbenzoyl)-3-thiophene sulfonamide 6 nM5-(4-t-butoxycarbonylbenzoyl)-3-thiophene 3 nMsulfonamide5-(3-benzoxybenzoyl)-3-thiophene sulfonamide 5.3 nM5-(4-formylbenzoyl)-3-thiophene sulfonamide 13 nM5-benzoyl-3-thiophene sulfonamide 13 nM5-(4-methoxybenzoyl]-3-thiophene sulfonamide 26 nM5-(1-heptanoyl)-3-thiophene sulfonamide 14 nM5-(1-pentanoyl)-3-thiophene sulfonamide 27 nM5-(4-carboxybenzoyl)-3-thiophene sulfonamide 3.4, 5 nM5-(4-hydroxybenzoyl)-3-thiophene sulfonamide 17 nM5-(4-acetoxymethylbenzoyl)-3-thiophene sulfonamide 6 nM5-(2-fluorobenzoyl)-3-thiophene sulfonamide 18 nM5-(3-fluorobenzoyl)-3-thiophene sulfonamide 12 nM5-(3,5-difluorobenzoyl)-3-thiophene sulfonamide 15 nM5-(1-hydroxypentyl)-3-thiophene sulfonamide 32 nM5-(4-hydroxymethylbenzhydrol)-3-thiophene 41 nMsulfonamide5-(4-formylbenzhydrol)-3-thiophene sulfonamide 18 nM5-(1-hydroxyheptanyl)-3-thiophene sulfonamide 31 nM5-(4-methoxybenzhydrol)-3-thiophene sulfonamide 16 nM5-benzhydrol-3-thiophene sulfonamide 74 nM5-(4-acetoxymethylbenzhydrol)-3-thiophene 21 nMsulfonamide5-(4-hydroxybenzhydrol)-3-thiophene sulfonamide 26 nM5-(3-hydroxybenzhydrol)-3-thiophene sulfonamide 37 nM5-[(hydroxy)(pyridyl)methyl]-3-thiophene 240 nMsulfonamide5-(acetoxyphenylmethyl)-3-thiophene sulfonamide 90 nM5-(4-methoxybenzoyl)-3-thiophene sulfonamide, oxime 31 nM5-heptyl-3-thiophene sulfonamide 21 nM5-(1-pentanoyl)-3-thiophene sulfonamide, oxime 22 nM5-[(methoxy)(4-hydroxymethylphenyl)]methyl- 13 nM3-thiophene sulfonamide5-[(methoxy)(3-trifluoromethylphenyl)methyl]- 18 nM3-thiophene sulfonamide5-benzoyl-3-thiophene sulfonamide, oxime 53 nM______________________________________ While particular embodiments of the invention have been described it will be understood of course that the invention is not limited thereto since many obvious modifications can be made and it is intended to include within this invention any such modifications as will fall within the scope of the appended claims.

The present invention provides novel carbonic anhyrase inhibitors represented by the structural formula: ##STR1## wherein R 1 and R 2 are, for example, independently (a) hydrogen; or (b) OR 4 , wherein R 4 is hydrogen or C 1-7 alkyl; or (c) NR 5 R 6 , wherein R 5 and R 6 are independently hydrogen, or C 1-7 alkyl, or C 1-7 alkyl substituted with one or more halogen or OR 4 ; or (d) --COR 7 , wherein R 7 is hydrogen, C 1-7 alkyl, or NR 5 R 6 ; or (e) --SR 8 , wherein R 8 is hydrogen or C 1-7 alkyl, or C 1-7 alkyl substituted with one or more halogen, or OR 4 ; or (f) C 1-7 alkyl, or C 1-7 alkyl substituted with one or more halogen, or OR 4 or NR 5 R 6 ; or (g) R 1 and R 2 are together (i) ═O, or (ii) ═NOR 8 or (iii) ═S; and R 3 is (h) C 1-7 alkyl or C 1-7 substituted with one or more halogen, OR 4 or NR 5 R 6 .

This is a division, of application Ser. No. 749,589, filed June 27, 1985, now abandoned. BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates in general to integrated circuits and in particular to integrated circuits in complementary circuit technology comprising at least two MIS field effect transistors of different channel types wherein the first is mounted in a doped semiconductor body of a first conductivity type and the second is mounted in a tub-shaped semiconductor body of a second conductivity type mounted in the semiconductor body. 2. Description of the Prior Art In integrated circuits of the complementary circuit technology wherein two field effect transistors of different channel types with the first one mounted in a doped semiconductor body of a first conductivity type and the second mounted in a tub-shaped semiconductor body of a second conductivity type and wherein the semiconductor body 2 of the second conductivity type is electrically connected to a supply voltage and the first field effect transistor is provided with a source terminal which lies at a reference potential there is a difficulty in that four successive semiconductor layers of alternating conductivity type are generally present between a terminal of a field effect transistor of the first channel type which is mounted in the tub-shaped semiconductor region and a terminal of a field effect transistor of the second channel type which is mounted outside of this zone such that the one connecting region of the first transistor forms the first semiconductor layer and the tub-shaped semiconductor region forms the second with the semiconductor body forming the third and the one connecting region of the second transistor forming the first semiconductor layer. When an overvoltage which exceeds the supply voltage by a specific amount, as for example 500 mV, occurs on the mentioned terminal of the transistor of the first channel type, the pn-junction between the first and second semiconductor layers can be positively biased to a degree such that a current path occcurs between the transistor terminals and this current path is attributable to a parasitic thyristor effect (latchup) within the four layer structure. This current path will also remain in effect after the decay of the overvoltage and can thermally overload the integrated circuit. SUMMARY OF THE INVENTION It is an object of the present invention to eliminate the disadvantages of the prior art described above. A feature of the invention is to provide a metal contact at the surface of a semiconductor region inserted into the semiconductor body and doped oppositely thereto with the metal contact forming a Schottky diode together with the semiconductor region and the metal contact is connected to a connecting region of the second field effect transistor whereas the semiconductor region is electrically connected to the supply voltage V DD . The advantages obtainable with the invention lie particularly in that the parasitic thyristor effect is avoided by means of a simple structure which particularly during manufacture of the circuit does not require any additional method steps but only slight modifications of the prior art steps: Other objects, features and advantages of the invention will be readily apparent from the following description of certain preferred embodiments thereof taken in conjunction with the accompanying drawings although variations and modifications may be effected without departing from the spirit and scope of the novel concepts of the disclosure and in which: BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exemplary embodiment of the invention; FIG. 2 is a circuit diagram of the exemplary embodiment of FIG. 1; FIG. 3 is a modified form of the invention; FIG. 4 is another embodiment of the invention; and FIGS. 5, 6 and 7 illustrate various steps in the method of manufacturing the embodiment of FIG. 1. DESCRIPTION OF THE PREFERRED EMBODIMENTS As illustrated in FIG. 1 an integrated circuit comprises a body 1 of doped semiconductor material, as for example, p-conductivity type silicon. The semiconductor body 1 contains a n-conductive tub-shaped conductor region 2 which extends up to the boundary layer 1a of the body 1. Mounted at the boundary surface 1a are field insulated regions 3a, 3b, 3c, 3d, and 3e which may be made of, for example, SiO 2 and between these insulation regions 3a through 3e, respective gate insulation regions which cover the active regions of the semiconductor circuit are mounted. There is provided in a first active region which is mounted in the lateral boundaries of the semiconductor region 2 a small p+ doped region 4 and a p+ doped region 5 which respectively form the source and drain regions of p- channel type field effect transistor T1. The channel region lying between regions 4 and 5 is covered by gate 6 which is provided with a terminal E and is separated from the boundary surface 1a by a thin gate insulation layer 7 of, for example, SiO 2 . A conductive coating 9 is applied to an intermediate insulation layer 8 which covers the gate 6 and it contacts the source region 4 through a window 10 formed in insulation layer 8 and is provided with a terminal 11. The terminal 11 is therefore is electrically connected to a supply voltage V DD . Another conductive coating 12 is connected to the intermediate insulation layer 8 and contacts the drain region 5 in the area of a window 13 and is electrically connected to a terminal A. An n-channel field effect transistor T2 is mounted in an active region lying between the insulation regions 3d and 3e and field effect transistor T2 is formed with n+ doped regions 14 and 15 which are formed in the body 1 as shown. A gate region 16 lies between the regions 14 and 15 and is separated by gate insulation layer 17. The gate 16 is connected to terminal E. A conductive coating 18 which contacts the drain region 15 through a window 19 of the intermediate insulating layer 8 is connected to terminal A and a conductive coating 20 which contacts the source region 14 through a window 21 is connected to a terminal 22 to which is applied a reference potential V SS . An n+ doped connecting region 23 is inserted into the semiconductor region 2 and this region 23 is contacted in the region of a window 24a by a conductive coating 24 mounted above the intermediate insulation layer 8 and the conductive coating 24 is connected to terminal 11. In the region of an additional window 25 of the intermediate insulation layer 8 a part of the conductive coating 12 forms a metal contact on the surface of the n-conductive semiconductor region 2 and this metal contact comprises a Schottky diode together with semiconductor region 2. Assuming an n-doping concentration about 10 16 cm -3 in the semiconductor region 2, the conductive coating 12 is expediently composed of aluminum. It is also advantageous if the conductive coating 12 is composed of tantalum silicide (TaSi 2 ) or it can be designed as a double layer which comprises a first layer of TaSi 2 and a second layer of aluminum which overlies the first layer. Other materials which are employed in a known fashion for Schottky diodes such as, for example, platinum or molybdenum may also be used for the conductive coating 12. Aluminum or the double layer of TaSi 2 and Al, however, have the advantage that they can also be employed for the coatings 9, 18, 20 and 24 such that all of the coatings on the intermediate insulation layer 8 can be applied in a single process step. It is essential that the leading threshold voltage V D of the Schottky diode D be lower than the leading threshold voltage of the pn-junction between the semiconductor region 5 and the semiconductor region 2 and this is referenced as V pn . As is illustrated in FIG. 2 the p-channel transistor T1 and n-channel transistor T2 are series connected with their source and drains connected to the supply voltage V DD which is supplied via 11 and 22 and their gates are electrically connected to the common terminal E. The Schottky diode D which is composed of parts 12 and 2 is inserted between terminals A and 11. In case a voltage which exceeds the supply voltage V DD by amount that is equal to or greater than the leading threshold voltage V D of the Schottky diode D appears at the inverter output A during operation, then D becomes conductive and limits the voltage V A to the value V A =V DD +V D . Thus, it is avoided that V A continues to increase and reaches or exceeds a value V A =V DD +V pn which causes parasitic thyristor effects to occur in the region of the four layer structures 5, 2, 1 and 14 with such thyristor effects potentially leading to the formation of a current path between terminals A and 22 and to a thermal overload of the entire structure. FIG. 3 illustrates a modification of the exemplary embodiment of FIG. 1 and differs from FIG. 1 in that the windows 13 and 25 are combined to a single window 13' and the conductive coating 12 which is designated by 12' in FIG. 3 contacts both the drain region 5' of T1 as well as the semiconductor region 2 in the area of this window. Since the drain region 5' is significantly higher doped than the semiconductor region 2, the coating 12' forms an ohmic contact on 5' and forms the Schottky diode D with the semiconductor zone 2. Another embodiment of the invention is illustrated in FIG. 4 wherein the Schottky diode D is arranged differently than in FIG. 1 and it lies in its own n-conductive semiconductor region 2' which is inserted into the semiconductor body next to the n-conductive semiconductor region 2. The region 2' has approximately the same doping concentration as region 2. The field insulation region 3b and 3c of FIG. 1 are combined into a single field insulation region 3b' and the coating 12" which replaces the coating 12 of FIG. 1 contacts only the drain region 5 of transistor T1. The field insulation regions 3d is divided into two regions 3d' and 3d" and the semiconductor region 2' is mounted therebetween. An n+ doped connecting region 26 is inserted into the semiconductor region 2' and this is contacted by conductive coating 27 in the area of a window 28 of the intermediate insulation layer 8. The coating 27 is connected to terminal 11. A conductive coating 29 which is composed of the same material as the coating 12 illustrated in FIG. 1 forms a metal contact in the area of a window 30 of the intermediate insulation layer 8 on the semiconductor region 2' and this metal contact comprises the Schottky diode D together with semiconductor region 2'. The coating 29 is connected to terminal A. In FIGS. 3 and 4, those parts which were described with reference to FIG. 1 are provided with the same reference characters as in FIG. 1. The modifications of FIGS. 3 and 4 operate in the same manner as that described for FIG. 1 and the electrical schematic of FIG. 2. In order to manufacture the circuit according to FIG. 1 an n-doped tub-shaped semiconductor region 2 which, for example, has a doping concentration of 10 16 cm -3 is inserted by means of a diffusion process into a body 1 of p-conductive silicon which has a basic doping concentration of about 10 15 cm -3 . Subsequently, a thin Si 3 N 4 layer is applied to the boundary surface 1a and such Si 3 N 4 layer being structured such by means of a photolithographic step that it remains only on the active semiconductive regions. Field oxidation regions 3a through 3e of SiO 2 are formed by means of thermal oxidation at those locations on the body 1 that are not covered by the Si 3 N 4 layer. After removal of the Si 3 N 4 layer portions, gate oxide layers S1 through S4 are grown on the active regions of the semiconductor body 1 by thermal oxidation process and these gate oxide layers form the previously mentioned gate oxide regions. The gates 6 and 16 of the field effect transistor T1 and T2 are then formed on the gate oxide layers S1 and S4 by using photolithographic steps and are formed therefrom with a polycrystalline silicon layer that has been applied on the surface. As is illustrated in FIG. 5 the n+ doped regions 14 and 15 of transistor T2 and the connecting region 23 are generated by means of ion implantation which is indicated by the arrows Im1. The lefthand part of the semiconductor body 1 extending up to the middle of the thick film region 3c is covered with a photoresist layer L1 during this time. Then the photoresist layer L1 is removed and as shown in FIG. 6, a further photoresist layer L2 is applied which covers the righthand portion of the body 1 up to the middle of the thick film region 3b whereby p+doped region 4 and 5 of transistor T1 are formed by means of ion implantation which is indicated by arrows Im2. As is illustrated in FIG. 7, an intermediate insulation layer of SiO 2 is applied using a deposition technique in a following method step and this layer 8 is provided with windows 10, 13, 21, 19, 24a and 25 above the regions 4, 5, 14 and 15 as well as above the connecting region 23 and between the field insulation regions 3b and 3c. These windows are etched through to the boundary layer 1a so that the gate insulation layers S1 through S4 indicated in FIG. 6 are also opened. For reasons of a simplified illustration the gate insulation layers S1 and S4 are not separately illustrated but are provided with the reference characters 7 and 17 since they lie under the gates 6 and 16. The remaining parts of S1 and S4 as well as the layers S2 and S3 are incorporated into the intermediate insulation layer 8 and are shown together with the insulation layer 8 as a uniform insulation layer. The conductive coatings 9, 12, 24, 18 and 20 are subsequently applied with this preferably occurring by means of a corresponding structuring of a surface wide coating by means of photolithographic steps. The coatings 9 and 24 finally are provided with the terminal 11 and the coating 20 is provided with the terminal 22 and the gates 6 and 16 are provided with the terminal E. The coatings 12 and 18 are provided with a terminal A. Other embodiments of the invention differ from those described in that the individual semiconductor parts are replaced by those of the respectively opposite conductivity types whereby the voltage of the opposite polarity can then be applied. In addition to these embodiments, the inventive concept also encompasses other integrated circuits in complementary circuit technology wherein at least two field effect transistors having different channel types are integrated in a semiconductor body such that at least one of them belongs to a first channel type and lies in a tub-shaped zone which is of a conductivity type opposite to that of the semiconductor body and where as least one other field effect transistor has a second channel type and is mounted in the semiconductor body outside of this zone. The tub-shaped zone is thereby always electrically connected to a supply voltage. The parasitic thyristor effect which was described under the Prior Art with reference to the transistors T1 and T2 which can occur in any circuit of this type is suppressed by the insertion of a Schottky diode between a connecting region of the field effect transistor lying in the tub-shaped zone and the terminal of the supply voltage when the leading threshold voltage V D of the Schottky diode is selected to be lower than the leading threshold voltage of the pn-junction between this connecting region in the tub-shaped zone. Although the invention has been described with respect to preferred embodiments, it is not to be so limited as changes and modifications can be made which are within the full intended scope of the invention as defined by the appended claims.

An integrated circuit in complementary circuit technology comprising two field effect transistors (T1, T2) of different channel types with the first one (T2) mounted in a doped semiconductor body (1) having a first conductivity type and the other FET (T1) mounted in a semiconductor zone 2 of a second conductivity type which is arranged in said body. The object is to provide a protection against thermal overloads which can appear due to "latch up" influences when overvoltages at the one connecting region of the field effect transistor (T1) mounted in the semiconductor zone occur. This is accomplished by the mounting of a metal contact (12) on the surface of a semiconductor region (2') inserted into the semiconductor body 1 and doped oppositely thereto with such metal contact forming a Schottky diode (D) with the semiconductor region (2') which can be connected to the connecting region of the field effect transistor T1 mounted in the semiconductor region 2 whereas the semiconductor region (2') is electrically connected to the supply voltage (V DD ). The circuits are applied in CMOS circuits.

[0001] This application is a divisional of application Ser. No. 10/226,190, filed on Aug. 23, 2002, which is hereby incorporated by reference in its entirety. FIELD OF THE INVENTION [0002] The present invention relates to image sensors which use a stacked avalanche multiplication layer to amplify the intensity of light captured by a pixel circuit. BACKGROUND OF THE INVENTION [0003] Amid the rising popularity for digital image devices such as digital cameras is a demand for increasingly higher picture resolution and for increasingly compact designs of such devices. Due to the interior space constraints in the housings of the compact designs, it is necessary to reduce the sizes of the electronic circuits in the device, including the image sensor. However, upon shrinking the size of the image sensor, a tradeoff must be made between resolution and the signal levels outputted from the image sensor. If the resolution is kept the same upon reducing the size of the image sensor, the size of each pixel must be proportionately reduced. Smaller pixels reduce the amount of charge that can be collected by each pixel during image exposure, which in turn reduces the sensitivity of the image sensor. Although the reduced sensitivity effect can be offset by increasing the integration (exposure) time, this is an undesirable “solution” because increasing integration time also increases the potential for obtaining a blurred image if there is any movement by the image subject or the device during exposure. On the other hand, in order to maintain the same sensitivity without having to increase integration time, the pixels must be made larger, which limits the resolution. [0004] One solution towards achieving both a more compact size and high image quality is disclosed in “CMOS Image Sensor Overlaid with a HARP Photoconversion Layer,” by T. Watabe, et al., published in the Program of the 1999 IEEE Workshop on (Charge-Coupled Devices and Advanced Image Sensors, pp. 211-214. In this image sensor, which is shown in FIGS. 1A and 1B , the pixel circuit 902 is overlaid with a stacked charge multiplying photoconversion layer, such as a high-gain avalanche rushing amorphous photoconductor (“HARP”) photo-conversion layer 904 for amplifying the fight signal produced by each pixel. [0005] When a photon 906 hits the upper surface 908 of the HARP layer 904 , a charge 910 in the form of holes is generated and amplified to many times its original level while being propelled through the HARP layer 904 to the bottom side 912 . The pixel circuit 902 is electrically connected to the bottom side 912 of the HARP layer 904 such that the amplified light signal 910 , upon reaching the bottom side 912 of HARP layer 904 , is conducted into the pixel circuit 902 as electrical charge. The charge accumulates at a storage node 914 in the pixel circuit until the pixel data is read out by activating the gate of a row select switch 916 . The amount of charge accumulated at the node 914 , which is proportional to the intensity of light 906 detected, is read out. In this manner, the image sensor of FIGS. 1A and 1B allows each pixel to capture image data with an intensity and sensitivity equivalent to that attainable by significantly larger pixels which do not have the avalanche multiplication capability. As a result, use of a HARP layer enables the image quality to be improved without having to increase the size of the image sensor array. [0006] In order to obtain avalanche multiplication in the HARP layer, an electric field of about 10 6 V/cm is required, which is achieved by applying an operating voltage of between 50-100 V to the HARP layer. In a typical HARP image sensor, voltages of less than about 8 V are used in the pixel circuit connected beneath the HARP layer, with the pixel circuit generally having a breakdown voltage of around 20 V. When the intensity of the incident light on the image sensor is at the upper end of the detection range for the charge multiplying photoconversion layer, the voltage level accumulating at the storage diode beneath the HARP layer approaches the level of the operating voltage applied to the HARP layer. Thus, voltages of 50-100 V may be applied to the storage diode when the image sensor is exposed to a strong light, resulting in a breakdown of the readout components of the pixel circuit. [0007] To address this problem, attempts have been made to build a pixel circuit having a higher breakdown tolerance. An example of such a high tolerance pixel circuit is disclosed in the article by T. Watabe et al. mentioned above, in which the pixel circuit is constructed as MOS transistor having a double drain structure. This structure is shown in FIG. 2 , in which the n-doped drain formed in the p-doped silicon layer 922 includes a low-dose n− region 924 surrounding a conventional high-dose n+ region 926 . The double drain MOS transistor structure was shown to achieve an endurance voltage up to just under 60 V. However, a special MOS fabrication process is required for forming the double drain MOS transistor, and the size of the MOS transistor makes it difficult to attain small pixel sizes for high resolution image sensors. BRIEF SUMMARY OF THE INVENTION [0008] The present invention mitigates problems of the high voltages which may be generated by a HARP layer under bright light conditions by incorporating a protection circuit into the pixel circuit connected to the HARP layer. The protection circuit prevents the pixel circuit from breaking down when the voltage in the pixel circuit reaches the operating voltage applied to the charge multiplying photoconversion layer in response to the image sensor being exposed to a strong light. In particular, the protection circuit of the present invention may be designed in any of several configurations in which additional voltage entering the pixel circuit from the charge multiplying photoconversion layer over a predetermined threshold voltage level is dissipated before reaching the storage node and other lower voltage components downstream therefrom. [0009] These and other features and advantages of the present invention will become more apparent from the following detailed description of the invention which is provided with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0010] FIG. 1A is a cross-sectional view of a pixel in an image sensor having a charge multiplying photoconversion layer as known in the art; [0011] FIG. 1B is a circuit diagram of the pixel arrangement shown in FIG. 1A ; [0012] FIG. 2 is a cross-sectional view of a double-drain MOS transistor as known in the art; [0013] FIG. 3 is a circuit diagram of a first preferred embodiment in accordance with the present invention; [0014] FIG. 4 is a circuit diagram of a second preferred embodiment in accordance with the present invention; [0015] FIG. 5 is a circuit diagram of a third preferred embodiment in accordance with die present invention; [0016] FIG. 6 is a circuit diagram of a fourth preferred embodiment in accordance with the present invention; [0017] FIG. 7 is a relevant portion of a circuit diagram in accordance with a fifth embodiment of the present invention; [0018] FIG. 8 is a relevant portion of a circuit diagram in accordance with a sixth embodiment of the present invention; [0019] FIG. 9 is a relevant portion of a circuit diagram in accordance with a seventh embodiment of the present invention; [0020] FIG. 10 is an example of an imaging apparatus incorporating the present invention, and [0021] FIG. 11 is an illustration of a processing system communicating with the imaging apparatus of the present invention. DETAILED DESCRIPTION OF THE INVENTION [0022] A first preferred embodiment of the present invention is shown in FIG. 3 , and is similar to the pixel arrangement shown in FIG. 1B in that it includes a charge (hole) multiplying photoconversion layer 102 connected to a voltage V target at its upper plate and connected to storage node 104 of a storage element 510 at its bottom plate. In this embodiment, storage element 510 is provided as a storage diode 106 . Although the charge multiplying photoconversion layer is preferably a high-gain avalanche rushing amorphous photoconductor (HARP) photoconversion layer, other structures for detecting and performing photoconversion of a light signal and subsequently or simultaneously amplifying the resulting electrical charge may be used. Storage node 104 is the cathode of storage diode 106 for accumulating charge corresponding to image data being collected during the image sensor integration time. An output circuit 500 is connected to and positioned downstream from node 104 , for reading out the charge accumulated at storage diode 106 . As shown in FIG. 3 , output circuit 500 may be simply constructed as a row select transistor 108 . [0023] The anode of storage diode 106 is connected to ground so as to block current flow through diode 106 when the voltage at node 104 is a higher level than the ground connection, which will always be the case when an image signal is received from the charge multiplying photoconversion layer 102 , since the signal charges are holes. Thus, with respect to storage diode 106 , therefore, as long as the row select transistor 108 is open, charge flowing from charge multiplying photoconversion layer 102 as a result of the detection of light will accumulate at node 104 . [0024] Row select transistor 108 of output circuit 500 is connected to a column readout line 110 so that when the gate for the row select transistor 108 is closed, the charge at storage node 104 is transferred to the column readout line 110 . When the column line containing the relevant pixel is activated, the image data from the pixel is transferred out of the pixel circuit 100 into an image processor where that charge is translated into image data along with the data read out from the other pixels in the image sensor array, to thereby construct the output image. [0025] In order to prevent the charge accumulating at node 104 from reaching the breakdown point of storage diode 106 or row select transistor 108 , a protection circuit 520 comprising a protection diode 112 , the anode of which is connected to node 104 of storage diode 106 . The cathode of protection diode 112 is connected to a voltage V dd , so that lichen the voltage level at storage node 104 reaches the level of V dd , any additional voltage arriving from the charge multiplying photoconversion layer 102 is bled off away from node 104 toward the voltage source V dd . In this manner, protection diode 112 selves to limit the voltage at node 104 to V dd . [0026] Once voltage is bled off from node 104 through protection diode 112 , image data representing light intensities detected at the upper end of the capability range of charge multiplying photoconversion layer 102 will be lost. Thus, the voltage level at source V dd should be set to strike a balance between minimizing the potential to lose image data acquired in the upper end of the detection range of layer 102 , and limiting the voltage at node 104 to a comfortable level to avoid the risk of breakdown of the storage diode 106 and the row select transistor 108 . [0027] A second preferred embodiment of the present invention is shown in FIG. 4 , and is identical to the pixel circuit of the first embodiment except that the storage element 510 is embodied as a storage capacitor 202 instead of a storage diode. Preferably, storage capacitor 202 has a large capacitance value per unit area, even more preferably in the range of 2-5 fF/μ 2 . Such a capacitor provides a higher capacitance value while reducing the space required for the charge storage region, relative to the use of a storage diode. [0028] In this embodiment, charge from the charge multiplying photoconversion layer 204 is stored in the capacitor 202 , until the voltage at the capacitor 206 reaches V dd . Additional voltage flowing to node 206 from the charge multiplying photoconversion layer 204 is then directed through the protection diode 208 of protection circuit 520 so that the charge stored in the capacitor 202 maintains a voltage of around V dd . [0029] A third preferred embodiment of the present invention, as shown in FIG. 5 , is identical to the pixel circuit of the first embodiment, except that the protection diode of the protection circuit 520 is replaced with an n-MOS transistor 302 . Both the drain and the gate of the transistor 302 are connected to the storage diode 308 of storage element 510 , aid the source of the transistor 302 is connected to a voltage potential of V dd . [0030] As in the embodiments described previously, charge from the image signal accumulates at the storage node 304 until the voltage at node 304 reaches and surpasses V dd . Once this occurs, the higher voltage at the transistor drain causes the excess voltage to flow through the transistor, so that the voltage at the storage node 304 remains around V dd . [0031] In a variant of this embodiment, the storage diode 308 of storage element 510 may be replaced with the high capacity capacitor as described above with reference to the embodiment of FIG. 4 . [0032] FIG. 6 shows a fourth preferred embodiment of the present invention, which is identical to the embodiment of FIG. 3 except that the protection circuit 520 further includes a resistor 402 positioned between the bottom plate 406 of the charge multiplying photoconversion layer 404 and the storage diode 408 of storage element 510 . The resistor preferably has a high resistance value which reduces the voltage passing through the pixel circuit 400 from the charge multiplying photoconversion layer 404 and the storage diode 408 at node 410 . [0033] The presence of protection circuit 520 , embodied here as protection diode 412 , provides additional protection for the pixel circuit 400 , so that in the event the signal voltage flowing from the charge multiplying photoconversion layer 404 is significantly larger than V dd that the voltage at node 410 upon passing through resistor 402 is still too high, the excess voltage will be directed away from the storage diode 408 and the row select transistor 414 through the protection diode 412 . [0034] A first variation of the FIG. 6 embodiment may be provided by replacing the storage diode 408 of storage element 510 with the capacitor discussed above in the embodiment of FIG. 4 . Similarly, the present invention also encompasses a second variation of this embodiment in which the protection diode 412 is replaced with an n-MOS transistor as described above in the embodiment of FIG. 5 . In a third variation of the FIG. 6 embodiment, both the storage diode 408 of storage element 510 and the protection diode 412 are replaced with the capacitor of FIG. 4 and the n-MOS transistor of FIG. 5 , respectively. [0035] In an image sensor using a charge multiplying photoconversion layer, as the voltage level at the storage node rises, the effective voltage applied to the photoconversion layer decreases, which affects the charge amplification function of the photoconversion layer. For example, if the voltage V target applied to the charge multiplying photoconversion layer is reduced, the amplification achieved by the photoconversion layer is also reduced. Thus, when the signal level is read out upon activating the row select switch, the signal level recorded by the imaging device will be less than the signal level actually detected. [0036] The fifth through seventh embodiments of the present invention, described below with reference to FIGS. 7-9 , address this concern. Each of the fifth through seventh embodiments is constructed by replacing the output circuit 500 in any of the embodiments shown in FIGS. 3-6 , with the respective circuit shown in FIGS. 7-9 . [0037] According to the fifth embodiment of the present invention, as shown in FIG. 7 , a differential amplifier 502 is connected to a constant voltage supply V ref at a positive input thereof, and the output is connected to a capacitor 504 in a feedback loop connecting to the negative input to the differential amplifier. A reset switch 506 is connected in parallel to the capacitor 504 between the negative input and the output of the differential amplifier 502 for shorting out the capacitor 504 . A row select switch 508 , which may be identical to the row select transistor 108 discussed above with reference to FIG. 3 , is also connected to the output of the differential amplifier downstream of the connection to the capacitor 504 . [0038] During the integration time in this embodiment, hole current from the charge (hole) amplifying photoconversion layer is inputted to the negative input of the differential amplifier, through the differential amplifier and through the feedback loop. In this manner, die hole current from the photoconversion layer is integrated on the feedback capacitor 504 . The output voltage of the differential amplifier is inversely linearly proportional to the intensity, of incident light on the photoconversion layer in that as the intensity, of light detected by the photoconversion layer increases, the output voltage from the differential amplifier decreases. When the row select switch 508 is closed, the output voltage of the differential amplifier 502 is read out. [0039] The differential amplifier 502 together with the feedback loop solves the problem of the decreasing amplification in the charge multiplying photoconversion layer by fixing the negative input voltage to the differential amplifier 502 at V ref , which in turn maintains the effective operating voltage V target of the charge multiplying photoconversion layer at a constant level. If no protection circuit 520 is provided as described above, when the intensity of light exceeds a normal operation level of the output circuit, the output voltage of the differential amplifier falls below its normal operation level, and the differential amplifier and the feedback loop lose the ability to function properly. In this case, the hole current begins to accumulate on a parasitic capacitor at the negative input to differential amplifier, and the voltage thereat begins rising towards the level of V target . [0040] The presence of the protection circuit 520 between the negative input to the differential amplifier 502 and the photoconversion layer in accordance with the present invention thus serves to prevent the output voltage of the differential amplifier falls below its normal operation level by diverting current from the photoconversion layer above the normal level and transferring the excess current through the protection circuit away from the differential amplifier. As described with respect to embodiments of FIGS. 3-6 above, the protection circuit 520 may be constructed as a protection diode, an n-MOS transistor, a resistor and a protection diode, or a resistor and an n-NMOS transistor. [0041] Since the intensity of light detected by the photoconversion layer is represented by the voltage of the output signal of the differential amplifier 502 and is integrated in the feedback loop during the integration time, the storage circuit 510 may be omitted in this embodiment, if desired. The presence or absence of the storage circuit 510 does not impact the operation of the pixel circuit, because the voltage at the negative input node of the differential amplifier 502 is fixed at V ref . In the event that the intensity of detected light exceeds the normal operation level of output circuit 500 , however, the presence of the storage circuit 510 serves as an accumulation point along the path between the photoconversion layer and the negative input of the differential amplifier from which the excess current can be bled off through the protection circuit 520 . [0042] The output circuit according to the sixth embodiment is shown in FIG. 8 , and is identical to the output circuit of FIG. 7 , except that the output circuit of FIG. 8 converts the hole current from the charge amplifying photoconversion layer into a logarithmic signal, to account for the decreasing amplification level of the charge multiplying photoconversion layer due to the inverse relationship between the voltage level at the storage node and the effective V target . In this regard, instead of a capacitor connected between the negative input and the output of the differential amplifier as shown in FIG. 7 , the output circuit of FIG. 8 provides a feedback diode 604 having its anode connected to the negative input of the differential amplifier 602 and its cathode connected to the output of the differential amplifier 602 . As configured in this manner, the output circuit of this embodiment thus logarithmically compresses the readout signal representing the intensity of the detected light. [0043] As shown in FIG. 9 , the output circuit of the seventh embodiment essentially combines the output circuits of FIGS. 7 and 8 , to thereby provide linear output signals in low light conditions and logarithmic output signals in brighter light conditions. Specifically, in this output circuit, a capacitor 704 is connected in parallel with a feedback diode 706 in a feedback loop connected between the output of the differential amplifier 702 and the negative input thereto. Capacitor 704 is similar to capacitor 504 discussed above with reference to FIG. 7 , and feedback diode 706 is similar to the feedback diode 604 discussed above with reference to FIG. 8 . [0044] Referring still to FIG. 9 , an offset voltage V off ( 708 ) is connected between the output of the differential amplifier 702 and the cathode of the feedback diode 706 to switch the pixel readout signals from a linear output to a logarithmic output, with the switching point defined by V off . Optionally, the switching point can be made adjustable by replacing the voltage V off with a capacitor, wherein V off is then selectively supplied to the capacitor 704 via a switch connected to a node between the feedback diode 706 and the capacitor 704 . [0045] More detailed descriptions of the output circuits shown in FIGS. 7-9 are provided in related U.S. application Ser. No. 10/226,326 entitled “A CMOS APS WITH STACKED AVALANCHE MULTIPLICATION LAYER WHICH PROVIDES LINEAR AND LOGARITHMIC PHOTO-CONVERSION CHARACTERISTICS,” the disclosure of which is hereby incorporated by reference, and which is commonly owned with and has the same inventorship as the present application. [0046] An example of an imaging device incorporating the present invention is shown in FIG. 10 . Specifically, an imaging apparatus 800 includes an image sensor 802 having a pixel array arranged according to a Bayer color filter pattern. A charge multiplying photoconversion layer such as a HARP layer is provided over each of the pixels in the array under the filter pattern. Each pixel 804 contains the protection and readout circuits in accordance with any one of the various embodiments discussed herein above. [0047] The imaging apparatus 800 further includes a row decoder 806 including a plurality of row select activation lines 808 corresponding in number to the number of rows in the pixel array of the image sensor 802 , wherein each line is connected to each row select switch in all the pixels in a respective row of the array. Similarly, column decoder 810 includes a plurality of column lines 812 , the number of which corresponds to the number of columns in the pixel array of the image sensor 802 . Each column line 812 is connected to the output sides of the row select switches in all the pixels in a respective column. [0048] To read the image data obtained by the image sensor 802 , controller 824 controls the row decoder 806 to sequentially activate the row select lines, whereby the row select switches for each pixel in a selected row is activated to thereby dump the image data from each respective pixel to the respective column line. Since each pixel in a row is connected to a different column line, the image data for each pixel is then read out to the image processor by sequentially activating all column select lines 813 to connect column lines 812 to column decoder 810 (via column select transistors 811 ). Thus, after activation of each row select line, the column select lines are sequentially activated to collect the image data in an orderly manner across the array. [0049] Upon reading the image data out of the pixel array, the data is passed through a number of processing circuits which, in linear order, generally include a sample and hold circuit 814 , an amplifier 816 , an analog to digital converter 818 , an image processor 820 , and an output device 822 . [0050] Without being limiting, such the imaging apparatus 800 could be part of a computer system, camera system, scanner, machine vision system, vehicle navigation system, video telephone, surveillance system, auto focus system, star tracker system, motion detection system, image stabilization system and other systems requiring an imager. [0051] The imaging apparatus 800 may also be connected to a processor system 850 , as shown in FIG. 11 , such as a computer system. A processor system 850 generally comprises a central processing unit (CPU) 852 that communicates with an input/output (I/O) device 854 over a bus 856 . The imaging apparatus 800 communicates with the system over bus 856 or a ported connection. The processor system 850 also includes random access memory (RAM) 858 , and, in the case of a computer system, may include peripheral devices such as a floppy disk drive 860 and a compact disc (CD) ROM drive 862 which also communicate with CPU 852 over the bus 856 . [0052] Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. Therefore, the present invention is to be limited not by the specific disclosure herein, but only by the appended claims.

An image sensor includes a pixel having a protection circuit connected to a charge multiplying photoconversion layer. The protection circuit prevents the pixel circuit from breaking down when the voltage in the pixel circuit reaches the operating voltage applied to the charge multiplying photoconversion layer in response to the image sensor being exposed to a strong light. The protection circuit causes additional voltage entering the pixel circuit from the charge multiplying photoconversion layer over a predetermined threshold voltage level to be dissipated from the storage node and any downstream components.

BACKGROUND OF THE INVENTION Such roller as a pinching roller used for such tape recorders as, for example, cassette tape recorders and VTR's has been conventionally formed as shown in FIG. 3. That is to say, in the drawing, the reference numeral 11 denotes a holder, 12 denotes a shaft, 13 denotes a spacer, 14 denotes an inner sleeve, 15 denotes a radial ball bearing, 16 denotes an outer sleeve made of brass, aluminum or the like and 17 denotes a roller body made of rubber or the like. In such conventional example, it has been common to provide a so-called double sealing structure by arranging sealing members 18 on both sides of the interior of the radial ball bearing 15 in order to prevent dusty fine powder such as rubber scraped off by the friction of the tape or the like in sliding contact with the surface of the roller body 17, from entering the radial ball bearing 15 through the path indicated by the arrows in FIG. 3. However, the above described conventional example has deficiency that the cost of the radial ball bearing 15 having sealing members 18 for preventing dust entry is high. SUMMARY OF THE INVENTION The present invention seeks to overcome the above mentioned deficiency and its object is to provide a roller wherein the formation of the radial ball bearing part is simplified, the manufacturing and assembling operations are made simple and the cost is reduced. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a first embodiment of a roller according to the present invention. FIG. 2 is a sectional view of a second embodiment of the present invention. FIG. 3 is of a conventional embodiment. DESCRIPTION OF THE PREFERRED EMBODIMENTS In the first embodiment of the present invention shown in FIG. 1, a columnar shaft 2 is supported between side pieces 1a and 1b of a holder 1, a hemispherical groove is made by cutting or the like in the middle of the shaft 2 to form a ball receiving part 2a and flange-shaped dust preventing projections 2b and 2c are formed over the entire periphery respectively on both sides of the ball receiving part 2a. A plurality of balls 3 are provided on the outer periphery of the ball receiving part 2a and are held by a substantially ring-shaped ball pressing member 4 arranged outside the balls 3. The ball pressing member 4 consists of two first and second tapered ball pressing members 4a and 4b, the members 4a and 4b being tapered, for example, substantially at 45 degrees at the inner end parts to contact and favorably hold the balls 3 and being provided with dust preventing projections 4c and 4d located respectively outside the projections 2b and 2c and extending toward the shaft 2. Slight clearances are formed respectively between the projections 2b and 2c and the inner peripheries of the first and second ball pressing members 4a and 4b and between the projections 4c and 4d and the outer periphery of the shaft 2. Further, the ball pressing member 4 is fixed to the inner peripheral surface of a cylindrical outer sleeve 5 arranged outside it. This outer sleeve 5 is, for example, die-cast and is fitted with a roller body 6 made of rubber on its peripheral surface. In assembling the elements, first of all, the roller body 6 is fitted on the outer peripheral surface of the outer sleeve 5 and is ground in advance on the outer peripheral surface. The first or second ball pressing member 4a or 4b on one side is pressed into a proper position on the inner periphery of the outer sleeve 5 and is fixed by a screwing means or binder. Then, the shaft 2 is inserted and set in a proper position with the already arranged first or second ball receiving member 4a or 4b through a proper jig (not illustrated). Then, a proper number of free balls 3 are put in together with grease or oil and are rotatably arranged between the outer periphery of the shaft 2 and the ball pressing member 4a or 4b on one side. Then the second or first ball pressing member 4b or 4a on the other side is pressed in and is fixed in a proper position on the inner periphery of the outer sleeve 5 by a screwing means or binder. While one side piece 1b of the holder 2 is bent and opened at the base end, the shaft 2 is locked at one end with a through hole of the other side piece 1a and then the above mentioned side piece 1b is bent back and is locked with the shaft 2 at the other end to easily assemble them. In the thus formed present invention, as no radial ball bearing is required, the cost can be substantially reduced. Such fine powder or dust of the rubber or the like as is slightly scraped off by a tape or the like running on the surface of the roller body 6 can be positively prevented by the dust preventing projections provided on both sides of the balls 3 from entering the ball part. Further, the component parts are so few and the respective members are of such comparatively simple forms that the assembling is easy. The second embodiment of the present invention shown in FIG. 2 is characterized in that the shaft 2 is left columnar, a ball receiveing part 2a' which is a separate member corresponding to the inner race of the radial ball bearing is provided substantially in the middle of the shaft 2, the balls 3 are arranged between this ball pressing member 4 and cylindrical spacers 7 are provided respectively on both sides of the above mentioned ball receiving part 2a'. In this embodiment, in assembling the roller, first of all, the roller body 6 is fitted to the outer sleeve 5, the first or second ball pressing member 4a or 4b on one side is secured as by being pressed in a proper poseition on the inner periphery of the outer sleeve 5, then the ball receiving part 2a' is positioned in the inner peripheral part of the already incorporated first or second ball pressing member 4a or 4b through a jig (not illustrated), a proper number of free balls 3 are inserted together with grease or oil, then the second or first ball pressing member 4b or 4a on the other side is pressed in and is fixed to the inner periphery of the outer sleeve 5 by a screwing means or binder, then the shaft 2 is inserted through the hole of the ball receiving part 2a' and the assembly completed by inserting the cylindrical spacers 7 from both directions may be fixed to the holder 1. By the way, a hemispherical groove to contact, hold and support the balls 3 is formed substantially in the middle of the ball receiving part 2a' and dust preventing projections 2b' and 2c' positioned respectively inside the projections 4c and 4d are provided respectively at both ends on the outer periphery of the ball receiving part 2a'. In this embodiment, there is an advantage that the shaft 2 is not required to be worked. As in the above, according to the present invention, there are effects that the formation is comparatively simple, the assembling is easy, the expensive radial bearing having conventional sealing members is not required and therefore the cost can be that much reduced.

This invention relates to a compact roller used as a tape recorder pinching roller for such as cassette tape recorders and VTR's or as a paper feeding roller for such as copying machines, facsimiles and printers.

This application claims the benefit of U.S. Provisional Application No. 61/716,677 filed Oct. 22, 2012, which is hereby incorporated by reference in its entirety as if fully set forth herein. FIELD OF THE INVENTION This invention relates to metal detectors with means to transmit, receive, and process signals. BACKGROUND OF THE INVENTION Induction metal detectors are generally designed to transmit either continuous wave (CW) signals, so-called frequency-domain (FD) detectors or to use pulsed or rectangular signals, so-called time-domain (TD) detectors. For the purpose of this invention description, a transmit waveform is understood to mean coil current unless otherwise noted. Often both types of designs use substantially similar receiver architectures: a preamp followed by one or more synchronous demodulation channels, integration and/or filtering, analog-to-digital conversion, and digital signal processing. To date, commercialized metal detectors that mix FD and TD in the same design are rare and tend to be user-selected to one mode or the other, but do not run simultaneously. Time-domain detectors are often referred to as pulse induction (PI) detectors, as most designs create a short pulse of current using a switched coil. When the current is switched off, the result is a high voltage flyback. The decay of the flyback is usually critically damped with a damping resistor, and the decay of the flyback is monitored for perturbations due to nearby metal targets. See U.S. Pat. No. 5,414,411. A typical pulse induction metal detector transmits a single pulse width duration of a consistent peak current amplitude, resulting in a single response that must be processed. Some methods have been described which use either multiple pulse width durations (see FIG. 1, U.S. Pat. No. 5,576,624) such as a series of short pulses 11 and long pulses 12. Some methods create differing peak current amplitudes (see FIG. 2 U.S. Pat. No. 6,653,838), such as a series of high current pulses 13 and a low current pulses 14. Either of the methods can produce variable responses to eddy current targets or to ferromagnetic ground or both. Typically such multiple responses are processed through multiple receive channels, whether such channels are realized in hardware, software, or a combination. These methods are analogous to so-called “multifrequency” metal detectors which use frequency-domain techniques. PI detectors are often used in military and humanitarian demining. Some land mines include a magnetic trigger, so this application requires the use of bipolar pulsing to avoid the creation of a non-zero net magnetic field (see U.S. Pat. No. 6,653,838 and FIG. 3) which shows a series of positive pulses 15 and negative pulses 16. Additional benefits are possible with bipolar pulsing. Subtracting the responses of the two polarities substantially cancels induced signals from the Earth's magnetic field and other low-frequency interferers while maintaining eddy current induced target responses. In many applications, a desirable feature in a metal detector is the ability to distinguish between various types of targets such as ferrous versus non-ferrous or low conductor versus high conductor. Currently available PI detectors generally exhibit poor discrimination capabilities. Frequency domain designs utilizing CW signals, especially sine waves, often use the target phase response to determine target characteristics. However, PI detectors generally achieve greater detection depths than do CW detectors, especially in ground which is high in mineralization or exhibits high magnetic viscosity. The ability to tune out mineralized ground is generally referred to as Ground Balance (GB). While both PI and CW designs include methods of ground balance, PI is inherently less sensitive to mineralization than CW. However, the GB method in many PI designs involves the subtraction of two signal samples, which not only reduces depth in general. The subtraction can also completely subtract out certain target responses, resulting in so-called “target holes” where particular targets cannot be detected at all. Needs exist for improved metal detectors. SUMMARY OF THE INVENTION This invention covers methods of generating and processing both types of signals in a single metal detector and running both types, CW and PI, simultaneously. The highly desirable solution combines the advantages of each system: the depth of PI with the discrimination of CW, plus a GB method which does not suffer from loss of depth or target holes. The invention provides a new and improved metal detector having one or more transmit coils for producing a cyclic transmitted magnetic field in response to a cyclic transmit current. Each transmit current cycle has one or more transmit current pulses that exhibit approximately a half-sine waveform during turn-on, which sinusoidally rises to a peak current, and which at or past the peak current is truncated by substantially shutting off the coil current. The shut off is followed by a turn-off time in which the applied transmit current is substantially zero. A transmit circuitry for generating the transmit current pulses applied to the one or more transmit coils has one or more switching networks for switching the one or more coils to appropriate drive circuitry having a unipolar or bipolar power supply voltage and one or more series-connected resonant capacitors for the purpose of producing a substantially half-sine response during the turn-on time. One or more receive coils receive a response signal created from the transmitted magnetic field and its effect on a surrounding matrix and conductive targets. A receive circuitry has a plurality of receive channels. Each channel has sampling circuitry and processing circuitry. The transmit current pulse is a truncated half-sine, which is truncated substantially close to the peak of the half-sine current waveform and after the peak of the half-sine current waveform. A transmit current pulse is followed by a turn-off time in which the applied transmit current is substantially zero, which is followed by a substantially identical transmit current pulse of opposite current polarity. A plurality of transmit current pulses are truncated half-sine current pulses of different pulse width durations with the same characteristic sinusoidal resonance response. Each pulse width duration is effected by a switching network for switching the one or more coils to drive circuitry that includes a series-connected resonance capacitor having a value selected to produce a truncated half-sine current response in which each pulse width duration has substantially the same truncation current level relative to its peak current level. In one form, the drive circuitry for each pulse width duration is powered by the same power supply voltage. In another embodiment, the drive circuitry for each pulse width duration is powered by a different power supply voltage. The power supply voltage is scaled according to the pulse width duration and resonance capacitor selection such that each pulse width duration has substantially the same current amplitude. One receive channel samples a received flyback response created by the truncation of the transmit current. The flyback response is called the flyback sample. Another receive channel samples a received half-sine response after the peak of the transmit half-sine current but before the truncation point, which is called the ground sample. The flyback sample and the ground sample are combined, and either or both samples are adjusted such that the combined response due to a ground matrix is substantially minimized. The metal detector has adjustment for one or more of sample delay, sample width, or sample gain. The adjustment is under the manual control of the user, or is under the automated control of the metal detector. A receive circuit samples a received half-sine response substantially at the peak of the transmit half-sine current which is called the X sample. The X sample is processed to determined characteristics of the ground matrix. The results are used to automatically adjust the ground sample such that the combined response of the flyback sample and the ground sample due to the ground matrix is substantially minimized. In one embodiment, a receive circuit samples a received half-sine response shortly after the beginning of the transmit half-sine current turn-on point, which is called the R sample. The X sample and the R sample are processed and compared to determined probable target type. In one embodiment of a metal detector, a receive channel samples a received flyback response created by the truncation of the transmit current which is called the flyback sample. The flyback sample is used to determine the presence of a conductive target, and the R sample is used to determine probable target type. The position of the R sample may be adjusted to change the response of certain target types for the purpose of accepting or rejecting certain target responses. In one embodiment, a plurality of pulse width durations are received and processed. The results are scaled and subtracted to substantially eliminate the response of saltwater. These and further and other objects and features of the invention are apparent in the disclosure, which includes the above and ongoing written specification, with the claims and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows varied pulse width in PI detectors. FIG. 2 shows differing peak current amplitudes in PI detectors. FIG. 3 shows bipolar pulsing in PI detectors. FIG. 4 shows an H-bridge driver in a CW detector. FIG. 5 shows an H-bridge driver in a PI detector. FIG. 6 shows a circuit of the present invention. FIG. 7 shows three of many possible responses. FIG. 8 shows coil current allowed to proceed beyond a peak for current cutoff. FIG. 9 shows bipolar truncated half-sine with two different widths and frequencies. FIG. 10 shows a circuit to implement bipolar transmission with two different frequencies. FIG. 11 shows a circuit with separate supply voltages for multiple frequencies. FIG. 12 shows a circuit similar to FIG. 6 with self-switching cross coupling. FIG. 13 shows cross coupled devices driven directly from NMOS devices. FIG. 14 shows typical waveform deflections from a single transmit pulse. DETAILED DESCRIPTION Bipolar transmit signals can be generated in a number of ways. A straightforward approach is to use an H-bridge driver with coil 21 , resistor 22 , capacitor 23 , and switches 31 , 32 , 33 , 34 which can drive current through a coil in either direction. This method has been used in both CW detectors 10 ( FIG. 4 ) and PI detectors 12 ( FIG. 5 ), the major difference being the addition of flyback diodes 41 , 42 , 43 , 44 in the PI version. In the CW method coil 21 can be resonated with a parallel capacitor 23 to generate a sine wave or left unresonated to generate a ramp waveform. A benefit of the H-bridge driver is that the responses of both current polarities are substantially matched. By adding a series-resonant capacitor to the PI H-bridge design it is possible to achieve a sinusoidal response during a turn-on duration along with a transient response at the turn-off point. FIG. 6 shows a circuit with a series-resonant capacitor 24 added. FIG. 7 shows three of many possible responses. The response 51 is similar to what some traditional PI transmit circuits achieve. Response 52 shows a quarter-sine response, whereby the H-bridge is turned off exactly at the peak of the sinusoid current. This has a performance benefit. In PI detectors it is desirable to have the coil charge current plateau to a reasonably constant level (di/dt=0) to allow forward-induced target eddy currents to die out before the coil current is shut off. Any residual forward-induced eddy currents will subtract from the desired reverse-induced eddy currents, reducing the overall target signal just after the coil turn-off event. The series resonant capacitor substantially speeds up this process compared to the normal exponential response of the coil alone. Response 53 shows a half-sine response, when the H-bridge is turned off exactly at the zero crossing of the sinusoid current. The frequency of the sinusoidal portion of the transmit signal is found by the traditional LC resonance equation, f = 1 2 ⁢ π ⁢ L ⁢ ⁢ C where L is the search coil 21 and reactance C is the series resonant capacitor 24 capacitance. Therefore, for a given L-C combination the clock timing can be varied to achieve a transient cutoff at any point during the sinusoid. It is also possible to implement a full sinusoidal (CW) current response. In current metal detector designs there is a trade-off between continuous wave, which offers good target identification through phase analysis, and pulse induction which offers greater depth through an impulse response. A hybrid system is desirable in which both a phase analysis and an impulse response are simultaneously present. This can be effected with the quarter-wave response 53 , but it is further advantageous to allow the coil current to proceed somewhat beyond the peak before cutting it off. As shown in FIG. 8 , this produces definite regions where the slope of the current is zero at the peaks, 55 and allows sampling the received signal on both sides 56 of the zero slope for the purposes of ground balance and determining target phase response. This waveform will be further referred to as a “truncated half-sine.” The truncated half-sine method and other circuit solutions are described in “Hybrid Induction Balance/Pulse Induction Metal Detector” (Earle), U.S. Ser. No. 61/398,298, now U.S. patent application Ser. No. 13/166,004. As mentioned before, some PI detectors utilize two or more transmit pulse widths to extract more information on ground and target signals. In continuous wave detectors, multiple sinusoidal frequencies are often used for the same purpose. The truncated half-sine can accomplish both methods simultaneously. FIG. 9 shows a (bipolar) truncated half-sine with two different pulse widths and resulting “frequencies.” Pulses 57 have a relatively wide pulse width and low frequency, and pulses 58 have a relatively narrow pulse width and high frequency. The multi-frequency truncated half-sine can be realized using an expanded version of the circuit in FIG. 6 . FIG. 10 shows a circuit which can implement bipolar transmission with the equivalence of two different frequencies. Capacitor 24 sets the frequency of a first half-sine, with transistor 31 , 32 , 33 , 34 providing the switching. Capacitor 25 sets the frequency of a second half-sine, with transistors 31 , 32 , 37 , 38 providing the switching. Diodes 47 and 48 are added near switches 37 and 38 . A relatively larger capacitor value of capacitor 24 , coupled with a longer turn-on time, produces a lower frequency, while a smaller capacitor 25 and shorter turn-on time produces a higher frequency. Additional frequencies may be added in similar fashion. This circuit does not quite produce the waveform in FIG. 9 . As both the capacitance and the turn-on time decrease, the amplitude of the resulting truncated half-sine also decreases. The result is a loss of sensitivity for the higher frequency, which is often compensated for by running multiple cycles of short pulses per each single long pulse cycle. See U.S. Pat. No. 5,537,041. This can better be remedied by using separate supply voltages for the multiple frequencies as shown in FIG. 11 . A lower frequency may be implemented with a larger capacitor 24 driven from a lower voltage 26 using transistors 31 , 32 , 33 , 34 . A higher frequency may be implemented with a smaller capacitor 25 driven from a higher voltage 27 using transistors 35 , 36 , 37 , 38 . Transistors 32 and 36 and diodes 42 and 46 are redundant and may be combined. The result is the desired waveform in FIG. 9 . All of the circuits described so far use both high-side (P-side) and low-side (N-side) switches driven from clock sources. Each switch may require its own unique clock signal even though some clock signals may have identical timing. This will often depend on drive voltage level needs. A simplification is to make some of the switches self-switching by connecting them in a cross-coupled manner. FIG. 12 shows the circuit in FIG. 6 having self-switching. In some configurations better switching performance is achieved when the cross-coupled devices are driven directly from the NMOS devices, as shown in FIG. 13 . Multifrequency truncated half-sine drivers such as in FIG. 11 may be similarly simplified. There are many variations of these concepts that will become apparent to anyone skilled in the art. In general, other switching devices such as bipolar transistors may be used in lieu of MOSFETs, and many of the flyback diodes may be eliminated. Most circuits have been shown as being powered from “+V” to ground, but a negative-referenced supply or bipolar supplies may be implemented. Unipolar current waveforms instead of bipolar may implemented. In FIG. 6 switches 33 and 34 may be eliminated, and capacitor 24 may be tied to a fixed voltage. In cross-coupled designs, cross-coupled N-side switches with clocked P-side switches may be implemented and, in fact, may be advantageous in some cases. The truncated half-sine transmit waveform results in an equivalent CW portion during the coil turn-on time and a PI portion at the point of coil switch-off. In order to receive and process the signal from the CW portion an induction-balanced coil is required. If a mono coil is used, then the PI portion can still be processed, but the CW portion cannot. While the transmit waveforms shown thus far represent the current through the transmit coil, the receive waveforms will represent the voltage at the receive coil. FIG. 14 shows typical received waveform deflections for a single transmit pulse 50 . The nominal receive waveform 60 during the turn-on time 50 is depicted as flat but will depend on the induction balance characteristics of the coil assembly. Response waveforms 61 , 62 , 63 , 64 are shown as typical deflections of the nominal waveform 60 . Similarly, at turn-off 59 the nominal receive waveform 70 will have a certain transient response dependent on the characteristics of the coil assembly and response waveforms 71 , 72 , 73 , 74 are shown as typical deflections of the nominal waveform 70 . During turn-on 50 both magnetic responses (ferrite and small iron) and eddy responses (nonferrous and large iron) produce deflections which exhibit pivoting about the nominal response 60 . This pivoting corresponds to phase shifts in traditional CW responses. Ferrite response 61 tilts counterclockwise about pivot point 67 . Because ferrite is theoretically lossless and ideally exhibits no phase shift, this should occur at the peak 55 of the transmit current where di/dt is zero. This point is called the “ground pivot.” A US nickel response 63 exhibits a clockwise tilt at a much earlier pivot point 65 , while a US silver dollar response 64 exhibits a clockwise tilt at a later pivot point 66 . Magnetic iron response 62 can either be viewed as a clockwise tilt with a pivot point occurring sometime before the start of turn-on period 50 , or as a counterclockwise tilt with a pivot point occurring sometime after the turn-off point 59 . In either case, most ferrous targets produce a negative response across the turn-on time 50 . The target responses at the turn-off point 59 follow traditional PI responses. All targets and ground exhibit the same deflection polarity, with the ground response 71 having approximately a l/t response and conductive responses 72 , 73 , 74 having approximately an exponential response compared to the nominal response 70 . In traditional ground balanced PI detectors a late sample is subtracted from an early sample in proper proportion to eliminate the ground response. The drawback is that all target responses are weakened at least a little, and a so-called “target hole” arises where a small range of target responses are completely or nearly eliminated. It should be noted that the deflections described are valid for one polarity of the transmit waveform, and for a bipolar transmitter the opposite polarity transmit waveform will produce opposite deflections. It should also be noted that the polarities of the deflections depend on how the coils are wound and connected. It is therefore understood that all waveform descriptions are illustrative and not absolute. Timing pulses 80 , 81 , 82 , 83 represent the sample points of the receive waveform for the purpose of signal processing. There are many ways to accomplish this including various synchronous demodulation schemes and direct sampling, and these various methods are within the scope of this invention. Timing pulse 83 is used to sample the response after the turn-off point 59 in a manner similar to traditional PI. This sample (herein called the “main” sample) produces responses of a consistent polarity for all conductors (e.g. US nickel 72 , US silver dollar 73 , and iron 74 ), and a relatively weaker response 71 for ground but also of the same polarity as conductors. The delay of pulse 83 relative to the turn-off point 59 is usually a few microseconds to 10's of microseconds, with a typical delay of 10 μs. Timing pulse 82 is used to sample the turn-on response 50 after the ground pivot point 67 . At this sample (herein called the “ground” sample) all conductive targets will have a negative polarity while ground will have a positive polarity. By properly scaling and subtracting the ground sample from the main sample it is possible to cancel the ground signal. At the same time, responses from all conductors will get stronger, which is opposite from traditional PI ground subtraction methods, and the “target hole” problem of traditional PI detectors is also eliminated. Any combination of sample delay, sample pulse width, or signal gain may be applied to either or both of the main sample or ground sample to effect ground signal cancellation. This may be manually controlled by the user or implemented as an automated system which tracks ground conditions. Timing pulse 80 is used to sample early in the turn-on response 50 and timing pulse 81 is used to sample at or very near the ground pivot point. These samples can be processed in a manner similar to CW as near-quadrature signal responses that produce amplitude and phase information. This phase information can then be used to determine the ground response by using techniques similar to those used in CW, and it is possible to effect an automated ground tracking method to compensate for ground variability by adjusting the scaling of the main and/or the ground signals. The phase can also be used to identify and discriminate conductive targets, also in a manner similar to those used in CW. Multiple pulse widths (frequencies) can produce varied responses to targets. For example, a relatively long pulse width (low frequency) may produce a stronger response to high conductors, and a relatively short pulse width (high frequency) may produce a stronger response to low conductors. Multiple pulse widths can be processed using individual processing channels or may be combined into common processing channels if the half-sine response curves are substantially alike. When using separate processing channels the results from two or more frequencies can be used to subtract the responses from salt water, which is advantageous when using a metal detector in a saltwater location. While the invention has been described with reference to specific embodiments, modifications and variations of the invention may be constructed without departing from the scope of the invention, which is defined in the following claims.

This invention relates to a metal detector where a coil is used to transmit a periodic magnetic field to energize metal objects that are concealed and often buried or hidden in a matrix (ground) containing ferromagnetic minerals. There are many difficult and often simultaneous challenges, such as detecting large deep targets, detecting minutely small targets, identifying target properties, ignoring the ferromagnetic matrix, avoiding a net magnetic field which can trigger magnetic sensors in land mines, and ignoring conductive salt responses. Either time-domain or frequency domain methods have been used to address these challenges with mixed levels of success. The ability to simultaneously use time-domain and frequency-domain methods can expand detection capability. Techniques are presented for achieving these goals.

FIELD OF THE INVENTION The present invention relates to an apparatus and method for depositing particulate food items. BACKGROUND OF THE INVENTION There has long been a need in the baking industry for a depositor which will uniformly distribute particulates, particularly raisins. Distribution should be uniform both in weight per time and across the material onto which the particulates are deposited, for example, a dough sheet. With particular reference to raisins, raisins have been problematic in their depositing. Three types of depositors have been used, those are vibratory feeders, for example, those made by Sintrum Co., screw feeders, for example, those made by Moline, paste spreaders and oscillating screens. These types of feeders have required that the raisins first be washed and then coated with a dry powder material to reduce stickiness. Even with such additional expensive and time-consuming processing, these types of feeders have been irregular or non-uniform in depositing and have caused damage to the raisins which are relatively soft and easily damaged by cutting or mashing. If the raisins are not pre-processed prior to distribution, the problems of distribution and damage are worse. It has long been a desire in the baking industry to be able to accurately deposit raisins and other food particulates accurately and without damage to them. The present invention provides means for depositing in a simple and inexpensive manner, from a machine standpoint, and also reduces the need for pre-processing of sticky particulates such as raisins. It was found that when using the present invention that raisins need only be washed prior to depositing and that the depositing with the present invention provided more uniform distribution both by weight per unit of time and uniformity across the width of the material being deposited upon. In the baking industry either a sheet of dough or dough pre-forms, for example, pre-formed rolls, have raisins deposited thereon as they move under a depositor. A dough sheet with deposited raisins can be further processed, for example, laminated, and then formed into pre-forms for subsequent cooking. The pre-forms with raisins thereon are typically ready for cooking after the depositing. Further, particulates can be deposited on a bakery item after the bakery item is cooked. Because of the variety of positions at which the depositing can take place, it has long been a desire to provide a depositor that was easily portable to various positions on the processing line. The present invention also solves this problem. Surprisingly, it was found that the present invention not only worked well with soft particulates, for example, raisins, but that it was also effective with numerous other particulate materials, for example, hard particulates like nutmeats or nutmeat portions, fragile particulates, for example, sliced almonds and streusel and non-uniformly sized particulates. The invention can also be used on fine particulates, for example, flours and cereal-grained meals and sugar. It is an object of the present invention to provide a depositor which will uniformly deposit soft particulates like raisins. It is another object of the present invention to provide a depositor which will handle a large variety of particulate materials. It is another object of the present invention to provide a depositor which will handle fragile or easily damaged particulates with minimal damage thereto during depositing. It is another object of the present invention to provide a depositor which is easily changed to accommodate different materials. It is another object of the present invention to provide a depositor which is portable and adapted for movement to various positions on a processing line. It is a still further object of the present invention to provide a depositor which overcomes the above discussed problems in the baking industry. It is a still further object of the present invention to provide a depositor which is simple in construction and easy to manufacture and maintain. FIGURES FIG. 1 is a side elevation view of the depositor. FIG. 2 is a side elevation view of the drive means. FIG. 3 is a sectional view along line 3--3 of FIG. 1. FIG. 4 is an end elevational section taken along the line 4--4 of FIG. 1. FIG. 5 is a schematic diagram of the air control system for the drive means. FIG. 6 is a schematic diagram of the electrical control system. DETAILED DESCRIPTION The reference number 1 designates generally a particular depositor which includes a support framework 2 having mounted thereon hopper means 3. The reference numeral 4 designates generally the drive means which is operable for driving portions of the hopper feed means 3. The support framework is generally U-shaped comprising bottom framework 6 having mounted thereon wheels 7. Secured to the bottom 6 is an upstanding frame portion 8 which has mounted thereon the drive means 4. A top frame member 9 is secured to the upstanding frame 8 and has the hopper feed means 3 mounted thereon. By being U-shaped, the depositor 1 can be easily moved into position on a processing line permitting the bottom frame to be positioned beneath a portion of the line and the top frame is positioned above the processing line. When the depositor is used for food depositing, it is preferred that all the materials be acceptable for use in a food plant and is typically stainless steel. The hopper feed means 3 includes an elongate hopper comprising side wall members 11 and 12 and end wall members 13 and 14. The end walls are generally parallel. The side walls can assume any desired shape and dimensions and preferably are shaped so as to prevent bridging and plugging during operation of the depositor. In the particular form shown, the side walls have upper portions 15 and 16 which are both angled relative to vertical with the included angle therebetween being in the range of between about 25° and about 40° total included angle. It has been found particularly desirable for raisins to have an included angle of approximately 36°. The end walls 13 and 14 and the side walls 11 and 12 are secured together in any suitable manner, as for example, by welding. A perforate or screen member 20 is suitably removably mounted on the hopper 3. Preferably, the screen 20 is mounted in a manner such that it can be easily removed for cleaning or changing. It is preferred that the screen have a round contour in cross section and it should generally match the contour of the lower positioned screw 21. The screen extends the length of the side walls 11 and 12 and is mounted thereon by hinges 22 and is secured in position by toggle latches 23. Preferably, the hinges 22 are of a kind that includes a pin 24 mounted on the side wall 11 and the screen 20 has slotted members 25 secured thereto such that after a certain amount of rotation thereof the hinge slot is in a position that the slotted member 25 can be disengaged from the pins 24. It is preferred that the screen be imperforate at each end for a length approximately equal to one flight of the lower screw 21, to provide a non-feed area for the particulate material in the hopper 3. Secured to the top frame 9 are support bars 26 and 27 which are positioned under the hopper means 3 and form a grid. It is desired to provide a deflector 28 which is generally V-shaped and extends the approximate length of the side walls 11 and 12. In operation, deflector 28 has the apex of the V pointing upwardly providing a diverging deflector with respect to particulate movement downwardly thereover. It has been found that the deflector helps provide uniformity of distribution of the particulates and also functions as an accumulator reducing the effect of the dead time during the reversal of the rotation oscillation of the screws in the hopper means 3. The deflector 28 can be loosely positioned under the hopper or can be permanently affixed thereunder. In a preferred embodiment of the present invention, the plurality of screws are mounted in the hopper feed means 3. As shown, two screws in superposed relation are provided. The screws 21 and 30 are suitably rotatably mounted in the hopper means 3, as for example, by bearings 31 secured to the end walls 13 and 14. The screws 21 and 30 are generally parallel to the side walls 11 and 12 with the lower screw 21 being positioned between the lower portions of the side walls 11 and 12 while the upper screw is mounted thereabove and being in superposed relation. The axis of the screw 30 is generally vertically above the axis of the screw 21. As shown the lower screw 21 can have a plurality of radially projecting pins 32, e.g., between every flight and extending in generally radially opposite directions. If desired both screws can have pins 32. The pins help break up materials that tend to clump together. For food products, it has been found particularly desirable to have the lower screw with an outside diameter in the range of between about one inch and about four inches. For raisins, it has found particularly good to have this diameter at two inches. It is preferred that the upper screw 30 be larger than the lower screw 21. Desirably, the upper screw 30 diameter should be in the range of between about 2 and about 5 inches. It is particularly desirable for depositing raisins that the upper screw 30 diameter be approximately 4 inches. Preferably, the diameter ratio of the lower screw 21 to the upper screw 30 is in the range of between about 1:1 and about 1:3. It is particularly desirable to have the screw diameter ratio of 1:2 for the depositing of raisins. As seen in the figures, there is a gap between the outer diameter of each of the screws and sidewalls and between the shafts 33 and 34 of the screws 21 and 30, respectively, and their respective side walls of the hopper. It is preferred that with the lower screw 21 that the gap A between the shaft and the wall be in the range of between about 1/4 inch and about one inch with a preferred spacing for raisins being 3/4 inch. For the upper screw 30, the gap B is preferred to be in the range of between about 3/4 inch and about 11/2 inch with a preferred gap B for raisins being 11/4 inch. It is also preferred that the ratio of the gap A to B be in the range of about 1:1 to about 1:2. Depending upon the particular type of material being deposited, the gap C and D between the screw flights and the side walls be in the range of between about 1/16 inch and about 1/2 inch and more preferably in the range of between about 1/8 inch and about 1/4 inch. In general, the smaller the particulate, the smaller the gap one can use without damaging the particulates during depositing. Also, depending upon the type of particulates being deposited, the screws 21 and 30 have a pitch in the range of between about one inch and about four inches and preferably for the depositing of raisins, the pitch is two inches. Also, it is preferred that during operation, that both screws 21 and 30, rotate simultaneously in the same direction and that the pitch also be in the same direction. However, other ranges can also be used. The screws 21 and 30 can have a length up to 60 inches or even more to provide depositing over very long distances. It is preferred that the side walls 11 and 12 be sufficiently high to provide a head over the top of the upper screw 30 in excess of four inches and for foods it is desired that the head be less than about 14 inches. Higher walls for the hopper could be provided so long as the head of material contained in the hopper is maintained within appropriate ranges. With regard to the screen 20, the size and shape of the openings 36 will be dependent upon the material to be deposited. Preferably, the holes are round and have a diameter in the range of between about 1/8 inch and about one inch. It has been found that numerous materials can be accurately deposited with 1/2 inch diameter openings. The drive means can be any suitable drive means effective to suitably drive the screws 21 and 30. In a preferred embodiment, the screws 21 and 30 simultaneously rotate in the same direction and oscillate or reverse direction at pre-selected intervals of rotation. Continuous rotation of the screws in one direction tends to damage the product. In the form of the invention shown, the drive means 4 includes a drive actuator 38 which is connected through suitable drive means to each of the screws 21 and 30 to effect their rotation. As shown, the drive actuator is a rotary actuator which is an air cylinder 39 with a rack and pinion drive connected to an output shaft in one direction of travel of the cylinder, the shaft rotates in one direction and on reverse movement of the cylinder, the shaft rotates in the opposite direction. The drive actuator 38 is connected to the screws 21 and 30 by a shaft 41. The shaft 41 has mounted thereon a sprocket which in turn is connected to the shafts of the screws 21 and 30 via sprockets 42 and a chain 43. In the form shown, operation of the drive actuator 38 rotates both shafts simultaneously in the same direction, both in forward and reverse directions. Speed of the drive actuator and hence the rotational speed of the screws 21 and 30, can be controlled as is known in the art by restricting the exhaust ports of the cylinder 39. In the illustrated form of the invention, this can be simultaneously accomplished by having a respective control valve 70 or 71 connected to each of the exhaust ports of the cylinder 39. The valves 70 and 71 can be connected together via sprockets and a chain 45 and 46, respectively. By having the valves 44 variable, restriction is also variable and therefore the operating speed of the cylinder 39. It is preferred that the rotational speeds of the screws be in the range of between about 20 rpm and about 200 rpm and preferably in the range of between about 40 rpm to about 140 rpm. The lower screw 21 and screen member 20 cooperate in a manner such that particulates are fed or deposited along the length thereof and not from the end of the screw as in typical screw feeders. The drive means further includes control means for effecting rotational reversal and as shown, that includes cam members 48 and 49 mounted on the shaft 41. During rotation, the cam members actuate limit switches 50 and 51, respectively, which in turn control the solenoid valve 67. For foods, it is believed that no more than about three revolutions of the screws 21 and 30 should be made before reversal. It has been found particularly desirable to have the screws rotate approximately one revolution before reversing. Although not shown, it is to be understood that the drive actuator 38 can be timed for on/off sequencing for spot depositing rather than continuous depositing. Further, funnel members can be placed underneath the screen 20 to have the particulates deposited in multiple strips rather than one continuous curtain across the width of the hopper. The two above can be combined for spot depositing in multiple strips. In order to provide safe operation, the depositor 1 can be provided with guards 52 and 53 at the depositing area. Microswitches 54 are mounted on the depositor 1 and are operative to electrically show that the guards 52 and 53 are opened or closed to form the interlocks. Likewise, the top grate or guard 56, which is hingedly mounted in the upper portion of the conveyor, can also have an interlock switch 57. As seen, the interlock microswitch 57 is mounted on an end wall of the hopper and the pivot pin (hinge) of the upper guard 56 extends thru the wall with an eccentric member to actuate the switch 57. Further, interlocks 57 and 54, respectively, can also be provided which cooperate with the guards 52 and 53 whereby upon opening of any of the guards the depositor 1 is disenabled and will not operate. Such safety features are known in industry. FIG. 5 shows a schematic diagram for the air supply system. As shown, air enters the system via a 3-way valve 62. By switching the valve from the position shown, air can also be exhausted to deactivate or depressurize the system. The valve 62 is connected via conduit means 63 thru a filter 64, pressure regulator 65 and a lubricator 66, to a 4-way, pilot-operated solenoid valve 67. The conduit means 63 then includes two conduits 68 and 69, each having connected therein, respective flow control valves 70 and 71 which are in turn, connected to the cylinder 39. FIG. 6 shows the electrical schematic for the depositor 1. As shown, a source of electricity 75 is electrically connected to solenoids 76 and 77 of the valve 67. As shown, one of the conductors 78 has connected therein a plurality of series connected switches. The first switch 79 is the main on/off switch and is manually operated; then in series are the switch 57 and two switches 54. Theses microswitches are interlocks and prevent the system from being activated in the event one or more of the guards is not in a closed position. As seen, the switches 50 and 51 and their respective solenoids 76 and 77 are connected in parallel to provide for separate operation of the respective solenoids. A depositor as described above was made with the hopper having a length of 48 inches, screen hole diameters of 1/2 inch with dead spaces of approximately two inches at each end of the screen. A lower screw with a two inch pitch and a two inch diameter with a gap A of 3/4 inches and a gap C of 1/4 inch and an upper screw having a diameter of four inches and a gap B of 11/4 inches and a gap D of 1/4 inches and a total included wall angle of 36° was operated. It was observed visually that the operation of this hopper produced an extremely uniform distribution of raisin which required only washing to effect. From the foregoing, it is seen that a depositor is provided which provides both versatility, portability and effective operation for a variety of materials. A particularly described depositor which was built provided exceptionally good depositing results on nutmeats, ground nutmeats, raisins, toasted coconut and the like. It provided operating results better than any known food depositor including vibrator trays, oscillating grates and screw feeders which feed particulates out the end of the screw instead of the side of the screw as is done by the present invention. Depositing with the present invention resulted in the ability to deposit particulates without destroying or damaging their texture, provide a uniform distribution both by weight with time and across the width of the depositor. Further, the present depositor is not only versatile and portable, but is inexpensive to manufacture. It is to be understood that while the present invention has been described in reference to certain types and arrangements of components the present invention is not to be limited thereto except to the extent that such limitations are found in the claims.

A depositor is provided for the feeding or distribution of particulate food pieces, as for example, raisins, nutmeats, etc. The depositor includes a pair of superposed screws positioned in a hopper over an outlet screen member. By oscillating rotational movement of the screws, the particulates are fed from the hopper through the screen onto a dough sheet or the like under the depositor.

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation of U.S. Non-Provisional application Ser. No. 12/546,056 filed on Aug. 24, 2009, which is a continuation of U.S. Non-Provisional application Ser. No. 11/650,323 filed on Jan. 5, 2007, which claims priority from U.S. Provisional Application Ser. No. 60/756,304 filed on Jan. 5, 2006, the disclosures of which are hereby incorporated by reference in their entirety. BACKGROUND There are many lotions and products applied to the human body for cosmetic purposes. These products include moisturizers, sunscreens, anti-aging treatments, UV tanning accelerators, sunless tanning products and much more. There are numerous forms of artificial tanning products currently available, including lotions, creams, gels, oils, and sprays. These products are typically mixtures of a chemically-active skin colorant or a bronzer, in combination with moisturizers, preservatives, anti-microbials, thickeners, solvents, emulsifiers, fragrances, surfactants, stabilizers, sunscreens, pH adjusters, anti-caking agents, and additional ingredients to alter the color reaction. There exist many automated systems for applying artificial tanning products and often include a closed booth provided with a spraying system. The spraying systems typically use high pressure compressed air nozzles, along with a fluid supplied to the nozzle to create an atomized spray directed towards the body. Currently, these booths are mostly closed, are limited to applying only one product per session, and create a foggy closed environment for the user. BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings and descriptions that follow, like parts are indicated throughout the drawings and description with the same reference numerals, respectively. One of ordinary skill in the art will appreciate that one element can be designed as multiple elements or that multiple elements can be designed as one element. An element shown as an internal component of another element can be implemented as an external component and vice versa. The figures are not drawn to scale and the proportions of certain parts have been exaggerated for convenience of illustration. FIG. 1 is a front-right perspective view of one embodiment of an automatic body spray system 100 ; FIG. 2 is a front-left perspective view of the automatic body spray system 100 ; FIG. 3 is a perspective view of one embodiment of a spray column 102 showing one embodiment of a slide out drawer 108 holding multiple solution containers 160 a - c; FIG. 4 is a perspective view of one embodiment of a rotating nozzle column 131 ; FIG. 5 is a detailed perspective view of the slide out drawer 108 holding multiple solution containers 160 a,b,c for use in the spray system 100 ; FIG. 6 is a side view of one embodiment of a fluid container 160 ; FIG. 7 is a perspective view of the backside of the slide out drawer 108 holding multiple solution containers 160 a,b,c showing fluid pumps 113 a - c; FIG. 8 is a perspective view of one embodiment of the spray column 102 with the back cover removed to expose the internal components; FIG. 9 is a perspective view of the nozzle arms 128 a,b and fluid solenoid valves 115 a,b,c located in the spray column 102 ; FIG. 10 is a detailed perspective view of one embodiment of an HVLP nozzle assembly 124 ; FIG. 11 is a perspective view of the HVLP turbine 118 , CPU controller 122 , and user interface 117 located in the spray column 102 of the spray system 100 ; FIG. 12 is a perspective view showing the backside of the mist extraction column 103 with the rear cover removed; FIG. 13 is a perspective view showing a mist extraction fan 142 , a mist extraction filter 140 , a filter compartment 141 , a filter wash down nozzle 146 , and an internal column wash down nozzle 147 of the spray system 100 ; FIG. 14 is a perspective view showing the mist extraction filter 140 removed from the mist extraction column 103 and also showing the mist extraction column 103 inlet vents 145 ; FIG. 15 is a perspective view showing one embodiment of a waterfall wash-down hose 149 ; FIG. 16 is a perspective view showing one embodiment of a sump pump 150 waste water removal system and sump pump filter 152 ; FIG. 17 is a side section view showing the sump pump 150 incorporated into a sump pump basin 151 that is integrated into the base 104 with a sump pump filter 152 ; FIG. 18 is a flow chart illustrating one method for operating the automatic body spray system 100 to coat the human body that can be employed by a controller. DETAILED DESCRIPTION FIGS. 1 and 2 illustrate left and right perspective views, respectively, of on embodiment of an automatic body spray system 100 . The system 100 includes a base 104 configured to support a human body 109 . Extending vertically from the perimeter of the base 104 are a spray column 102 , a mist extraction column 103 , and partial side walls 105 a , 105 b , which together defined a spray booth to house the user therein. These partial sidewalls 105 a,b contact the spray column 103 and continue in a curved pattern toward the spray column 102 (see also FIG. 15 ). The partial sidewalls 105 a,b also seat against the base 104 at the bottom of the system 100 . The partial sidewalls 105 a,b stop short of the spray column 103 to allow for user access into the system 100 . The partial sidewalls 105 a,b can be of any shape or size and can be modified to provide the desired amount of mist containment. A partial top 180 can also be provided to keep any excess mist from escaping out the top of the system 100 . In an alternative embodiment, the system 100 can include full-size sidewalls, instead of partial walls. In a preferred embodiment, the system 100 can be employed to apply sunless tanning solutions as well as other solutions onto a human body 109 . Exemplary sunless-tanning solutions include one or more colorants, such as dihydroxyacetone, crotonaldehyde, pyruvaldehyde, glycolaldehyde, glutaraldehyde, otho-phthaldehyde, sorbose, fructose, erythrulose, methylvinylketone, food coloring, or any other available colorant. The sunless tanning solutions can additionally or alternatively include one or more bronzers, such as lawsone, juglone, or any other available bronzer. It will be appreciated that the sunless-tanning solutions can include additional ingredients, such as moisturizers and scents, to make the solution more appealing to a user. While the system 100 can be employed as a sunless tanning spray system, it can also be employed to spray other fluids onto the human body. For example, the system 100 can be configured to spray sunscreens, suntan lotions, moisturizing lotions, sunless tanning pre-spray treatments, tanning accelerators, sunburn treatments, insect repellants, skin toners, skin bleaches, skin lighteners, anti-microbial compositions, exfoliants, nutriments or vitamins, massage aides, muscle relaxants, skin treatment agents, burn treatment agents, decontamination agents, cosmetics, or wrinkle treatments or removers, or any other solution or lotion desired to be applied to the human body. As shown in FIG. 3 , the spray column 102 includes two high volume, low pressure (HVLP) atomization nozzles 106 a,b fluidly connected to an HVLP turbine (not shown) with an air supply hose and also fluidly connected to at least one fluid container 160 . With the assistance of the HVLP turbine, the HVLP nozzles 106 a,b are configured to eject an atomized mist of fluid. In alternative embodiments (not shown), the spray column 102 may include one HVLP nozzle or more than two HVLP nozzles. In another embodiment (not shown), a high pressure fluid pump may be employed, instead of the HVLP turbine. Each HVLP nozzle 106 a,b is coupled to a linear slide (not shown) that is configured to move the HVLP nozzles 106 a,b up and down vertically, thereby adjusting the vertical of the HVLP nozzle 106 a,b . In this configuration, the HVLP nozzles 106 a,b are moveably mounted to the spray column 102 , such that the spray pattern of the HVLP nozzles 106 a,b is sufficient to completely coat the human body 109 with a desired fluid, solution, or lotion. In an alternative embodiment as shown in FIG. 4 , a vertically standing column 131 that rotates back and forth about its vertical axis can be employed. One or more HVLP nozzles 106 can be mounted to the rotating column 131 and be connected to an HVLP turbine with an air supply hose and also fluidly connected to at least one fluid reservoir or container 160 . This column can be automatically rotated back and forth to automatically coat the human body. With reference back to FIG. 3 , the system 100 includes three fluid containers 160 ac contained in the drawer 108 . In alternative embodiments, the system 100 can include two or less containers or more than three containers provided in the drawer 108 . As shown in FIG. 3 , a start button 110 and an LCD user interface panel 107 are also provided. The start button 110 is used to initiate a session. The LCD user interface is used to set up a session and also to perform other functions including, but not limited to, defining the system parameters, turning on a wash down function, turning on a light, and viewing session counts. FIG. 5 illustrates a perspective view of the fluid container drawer 108 with the drawer 108 opened to expose the fluid containers 160 a,b,c . The drawer 108 provides for a simple method of accessing the containers 160 . The drawer 108 includes a pull handle 111 and a key lock 112 for security purposes. In this embodiment, the drawer 108 is attached to the spray column 102 with two slide rails 113 a,b . The drawer 108 can also be attached to the spray column using a rotating mount or any other type of mount. As discussed in more detail above, the fluid containers 160 a - c can hold sunless tanning solutions or other types of fluids. In one embodiment, each fluid container 160 a - c can hold a different sunless-tanning solution. The different solutions can have different chemical compositions which affect the hue of the resulting tan. Alternatively, one fluid container (e.g., the first fluid container 160 a ) can contain water or another dilution agent to dilute a solution contained in the second solution container (e.g., the second fluid container 160 b ). The contents of the different fluid containers can be mixed in various combinations to provide a range of shades, thereby allowing the user to select a preferred tanning shade. Also, the fluid containers can hold other types of solutions to be applied to the human body. One control method for applying the solutions can be to apply a first atomized solution, dry the body with air only coming from the HVLP nozzles, apply a second atomized solution, dry the body with air only coming from the HVLP nozzles, apply a third atomized solution and then dry the body with air only coming from the HVLP nozzles. FIG. 6 illustrates a side view of one embodiment of a fluid container 160 . In this embodiment, the fluid container 160 includes a handle 164 , a male quick disconnect valve 161 at an opening located at one end portion of the fluid container 160 , and a vent 162 provided at the other end portion of the fluid container 160 . The fluid container 160 can also include a check valve 163 to ensure that fluid flows in only one direction such that, when the fluid container 160 is empty, the check valve 163 will prevent any residual solution from leaking out when the fluid container 160 is removed. It will be appreciated that the fluid container 160 can be configured differently in shape and size from the one illustrated in FIG. 6 . Also, it will be appreciated that different fittings such as interchange couplings, poppet couplings, or threaded couplings, can be used to dispense solution from the fluid container 160 . In one embodiment, the fluid containers 160 a - c are removable. Alternatively, the spray column 102 can house fixed fluid containers that can be filled with solution while still in spray column 102 when the solution level falls below a predetermined threshold. As shown in FIG. 4 , each fluid container 160 a - c is inverted such that the male quick disconnect valve 161 mates with a female quick disconnect fitting 165 a - c disposed in the drawer 108 . When a new fluid container 160 is added to the system 100 , the male quick disconnect valve 161 of the fluid container 160 is snapped into the female quick disconnect fitting 165 a - c in the drawer 108 . The vent 162 on the fluid container 160 can then be opened to equalize the air pressure inside the fluid container 160 , allowing fluid to flow freely. FIG. 7 is a perspective view of the inside of the drawer 108 containing three fluid pumps 113 a - c positioned below the female quick disconnect fittings 165 a - c . The first pump 113 a is configured to pump the solution held in the first fluid container 160 a along a fluid flow path F 1 through the hose assembly 116 to the HVLP nozzle assemblies 106 a,b . The second pump 113 b is configured to pump the solution held in the second fluid container 160 b along a fluid flow path F 2 through the hose assembly 116 to the HVLP nozzle assemblies 106 a,b . the third pump 113 c is configured to pump the solution held in the second fluid container 160 c along a fluid flow path F 3 through the hose assembly 116 to the HVLP nozzle assemblies 106 a,b . In one embodiment, the pumps 130 a,b,c are positive displacement pumps. Any other type of fluid pump may suffice. It will be appreciated, however, that one or more of the pumps 113 a,b,c can be positioned anywhere in the drawer 108 . FIG. 8 illustrates a simplified perspective view of the interior of the spray column 102 . FIG. 9 is a close up view of FIG. 8 showing the HVLP nozzle mounting arms 128 a,b in one embodiment of the system 100 . The nozzle mounting arms 128 a,b also hold fluid solenoid valves 115 a - c . These solenoid valves 115 a - c turn on or off the fluid flow through fluid paths F 1 , F 2 , and F 3 between fluid pumps 113 a - c and the HVLP nozzle assemblies 106 a,b . The solenoid valves are controlled by the controller 122 . The valves 115 a - c can also be any type of suitable control valve. The hose assembly 116 holds the fluid paths F 1 , F 2 , and F 3 as well as the air path A 1 . The three fluid paths F 1 , F 2 , F 3 route to each solenoid valves 115 a - c , respectively, and than to each nozzle assembly 106 a,b . The air path A 1 routes to each nozzle assembly 106 a,b from the HVLP turbine 118 and through hose assembly 116 . FIG. 10 shows a detailed perspective view of an HVLP nozzle 106 and mounting arm assembly 124 . The top of nozzle body 126 mounts to the bottom side of the nozzle mounting bracket 129 . The nozzle mounting bracket 129 mounts to the moveable nozzle arm 128 a or 128 b . The HVLP air supply line A 1 enters the nozzle body 126 from the backside and the three fluid lines F 1 , F 2 , F 3 all enter the nozzle body 126 from one of the other sides. The fluid paths for F 1 , F 2 , F 3 all merge toward the center of the nozzle body 126 internally and exit at nozzle tip 127 . The HVLP air supply from the air path A 1 also exits the nozzle body 126 at the nozzle tip 127 . In this embodiment, the HVLP air and the fluid are externally atomized at the nozzle tip 127 . It can be appreciated that any number of fluid paths may enter the nozzle body 126 . Also shown in FIG. 10 are check valves 133 a - c . The nozzle body 126 with multiple inlet ports and the check valves 133 a - c allow multiple solutions to enter the nozzle body 126 and eliminate any cross contamination of different fluids. FIG. 11 is a close up view of FIG. 8 showing the HVLP fan 118 mounted inside the spray column 102 . The hose assembly 116 carries the air path A 1 from the HVLP fan 118 to the nozzle assemblies 106 a,b . The HVLP fan 118 can be controlled on or off by use of a relay or other type of electronic switch. The relay or switch is controlled by the main controller 122 . This HVLP fan 118 acts as the air source to atomize any desired solution or fluid. Another embodiment is to have a heating source that the HVLP air passes through to provide a warmer spray and dry session to the user. This heating source can be controlled by the controller 122 . In the illustrated embodiment, the controller 122 is configured to control the operation of the system 100 . Specifically, the controller 122 is configured to operate the HVLP nozzles, HVLP turbine, pumps, valves, and other electrical or electro-mechanical devices in the system 100 . Suitable controllers can include a processor, a microprocessor, a control circuit, a PLC, or any other appropriate control device. FIG. 11 also shows the controller 122 and the LCD user interface panel 107 . The main controller 122 can be programmed many ways to operate the system 100 for its desired function. For example, in one embodiment, the controller has pre-programmed parameters such as fluid pump values (these control the speed of each fluid pump 113 a - c via pulse width modulation which in turn controls how much fluid is applied over a period of time therefore controlling the intensity level of the fluid being sprayed), linear slide speed (this can control the speed of a linear slide that moves the nozzles 106 a,b vertically up and down; this will also control the amount of solution applied over time and also the length of each application session), number of spray passes (this parameter controls how many times the body is sprayed). Any other variable that controls the operation of the machine can be stored and modified with the LCD interface display 107 and main controller 122 . With continued reference to FIG. 7 , the LCD interface display 107 and main controller 122 can be programmed and configured to perform many unique application sessions. In one embodiment, a linear slide that moves nozzles 106 a,b up and down vertically can be controlled with a motor drive system and any type of position encoding device. The encoding device can be connected to the main controller 122 so that the controller always knows the position of the nozzle arm 128 a,b . This encoding system allows a user to select a partial body spray application. For example, the user can select to spray just their face, input their head height, and the system 100 will spray just their face with the desired solution or combination of solutions at the selected levels. Another example is that the user selects to just spray their legs or their whole body, excluding their legs or face or both. A height monitoring sensor can also be added to the control system so that it automatically adjusts the nozzle 106 a,b positions for each user. This can also be used for full body sprays where the starting height of the nozzles 106 a,b are adjusted to the height of each user, thereby reducing the amount of solution sprayed for bodies shorter than the maximum height of the nozzles 106 a,b. With reference back to FIGS. 1 and 2 , the system 100 also includes a mist extraction column 103 a described above. The mist extraction column 103 can be mounted to the base 104 in a relative position opposite the spray column 102 . The mist extraction column is used to capture any excess mist during spray sessions. FIG. 12 is a perspective view showing the internal components of the mist extraction column 103 . The mist extraction fan 142 will be turned on by the controller 122 during a spray session to draw air flow and excess spray mist through vent openings 145 through a filter assembly 140 that is supported by a filter compartment 141 . The mist is captured in the filter 141 and clean air is passed through the fan 142 and out the back of the mist extraction column 103 . The size and CFM of the mist extraction fan 142 can be adjusted to provide the required amount of air flow to contain the mist generated by the HVLP nozzles 106 a,b. FIG. 13 is a detailed perspective view of the internal components of the mist extraction column 103 . Provided in a position relative to filter 140 is a filter wash down nozzle 146 . The filter 140 in this embodiment is oriented in a horizontal position parallel to the ground plane. The mist extraction column 103 also provides for an internal column wash down nozzle 147 . This column wash down nozzle 147 can be used to clean the inside of the mist extraction column 103 to eliminate the buildup of any spray residue that may occur. This internal column wash down nozzle 147 can have a water supply line connected to it with a solenoid valve (not shown). This solenoid valve can be activated by the controller 122 to provide for a mist extraction column 103 cleansing cycle after each spray session or at desired intervals. In another embodiment, a manual valve could be used to control the water supply to the internal column wash down nozzle 147 . The number of fans, filters, and nozzles or orientation of the fans, filters, and nozzles can be modified as needed. FIG. 14 shows how the filter is inserted and removed from the mist extraction column 103 . The filter 140 slides in a direction perpendicular to the front of the mist extraction column 103 and allows for easy removal. The wash down nozzle 146 can have a water supply line connected to it with a solenoid valve (not shown). This solenoid valve can be activated by the controller 122 to provide for an automatic filter cleansing cycle after each spray session or at desired intervals. The horizontal position of the filter 140 in this embodiment allows for the filter cleansing water to be passed through the filter 140 and emptied at the bottom of the mist extraction column 103 . In another embodiment, a manual valve could be used to control the water supply to the filter wash down nozzle 146 . FIG. 15 shows a perspective view of a wash down system hose 149 used for this open system design. Because the system is open, care has to be taken when providing for an automatic wash down system so that excess wash down water does not leak out of the system. This embodiment shows the wash down hose 149 having holes along its length pointed toward its mounting surface. In this embodiment, the wash down hose 149 mounts along both side walls 105 a,b and the mist extraction column 103 . This configuration allows a waterfall-type wash down where the rinsing water is softly directed in a many small streams toward its relative mounting surface and runs down the surface to be cleaned. This waterfall wash down hose 149 can have a water supply line connected to it with a solenoid valve (not shown). This solenoid valve can be activated by the controller 122 to provide for system 100 cleansing cycle after each spray session or at desired intervals. In another embodiment, a manual valve could be used to control the water supply to the water fall wash down hose 149 . FIG. 16 shows a simplified perspective view of a waste water sump pump 150 mounted in base 104 . FIG. 17 shows a side section view of a waste water sump pump 150 mounted in base 104 . The base 104 has an integral drain basin 151 to catch waste water from the various wash down systems described above, including the filter wash down waste water, the internal column wash down waste water, and the system wash down waste water. The waste water from the above mentioned wash down systems flow down from their respective components to be cleaned over the top surface of the base 104 and towards the sump pump basin 151 . The waste water also passes through a filter screen 152 to keep debris from entering the sump pump 150 . The sump pump 150 will then pump out the waste water when its float switch activates the pump. The fluid spraying system 100 can include additional components without departing from the scope of the present application. For example, the system 100 can include fluid detection sensors (not shown) disposed near the bottom of each fluid container 160 a,b,c . The fluid detection sensors can be configured to sense the solution level in each fluid container 160 a,b,c . When the solution level falls below a predetermined threshold, the fluid detection sensors can be configured to transmit a signal to the controller 122 . Upon receipt of the signal, the controller 122 can deactivate the fluid spraying system 100 to prevent air from being pulled into one or all of the fluid flow paths F 1 , F 2 , and F 3 . Exemplary fluid detection sensors that can be employed include capacitive solution detection switches, optical sensors, or piezoelectric sensors. Also, the fluid spraying system 100 can include a heating element (not shown), such as a heating coil or other heating device, that can be placed around or adjacent to the first and/or second and/or third fluid flow paths F 1 , F 2 , F 3 thereby creating a warm, atomized mist of fluid that can be ejected from the nozzles 106 a,b . Additionally, a heating element can be placed around or inside the air flow path A 1 . Alternatively, heating elements can be placed around or adjacent to one or all of the fluid containers 160 a,b,c. FIG. 18 is a flow chart showing one example of a control process. This process shown is for a full body session and a choice between a single solution spray or a multiple solution spray. The multiple solution spray shown in this example is for a two solution multispray but can be configured for any number of multi-session sprays. This flow chart can also apply for face only sprays, leg only sprays, or any other height adjustable spray session. In one specific method to coat the human body, the method can include spraying can the atomized mixture of HVLP air and fluid onto the body and then turning off the fluid supply and moving the nozzles up and down with the HVLP air still on to dry the body. The speed, volume, and temperature natural to the HVLP air source is ideal for drying the body. Hence, the same nozzles that apply the atomized solution can also be used as a drying source when the solution is turned off and the air is turned on. The system 100 described above and illustrated in the figures provides one or more of the following benefits: (1) the system does not require a large external air compressor for air delivery method, (2) the atomized spray using an HVLP air supply does not produce a lingering fog of mist and over spray, because of the lack of fog and over spray, (3) the system does not need to be completely enclosed to capture excess mist and keep it from escaping into the surrounding environment, (4) the user is not subjected to breath or be surrounded by excess fog or mist, and the transfer efficiency of the atomized fluid onto the human body is much higher than with compressed air systems, (5) the system allows many different types of products to be applied to the human body in one application session, (6) the system employs the use of a convenient slide out drawer to access the solution containers for multiple products to be applied, and (7) the system can be programmed to apply a fluid to only user specified areas of the body. While the present application has been illustrated by the description of embodiments thereof, and while the embodiments have been described in considerable detail, it is not the intention of the applicants to restrict or in any way limit the scope of the appended claims to such detail. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the application, in its broader aspects, is not limited to the specific details, the representative apparatus, and illustrative examples shown and described. Accordingly, departures can be made from such details without departing from the spirit or scope of the applicant's general inventive concept. The system is not designed solely for sunless tanning products or for the purpose for spraying a human body. It can accommodate almost any type of product being sprayed.

An embodiment of an apparatus for extracting excess liquid in a human body spray system includes a spray booth defining a booth volume. The spray booth includes a base configured to support the human body and a column having walls extending vertically from the base and at least one vent opening disposed on a bottom half portion of the column on at least one of the walls. The walls form a hollow interior of the column. The apparatus for extracting excess liquid in a human body spray system further includes an extraction fan disposed within the hollow interior adjacent to a top half portion of the column and configured to create a low pressure volume within the hollow interior and draw air flow and at least some of the excess mist from the booth volume through the at least one vent opening.

TECHNICAL FIELD This invention relates generally to gas lasers and more particularly to matching and drive systems for transversely excited gas lasers. BACKGROUND OF THE INVENTION Interconnection and matching of an RF excited gas laser to an RF generator is typically accomplished by the use of a 50 ohm coaxial transmission line with separate matching networks at both ends. The matching network at the laser end usually steps up the line impedance to a range between several hundred and several thousand ohms, while the matching network at the RF generator end steps the line impedance down to the low values required for the generator's transistor output stage. Other functions of the matching networks are to account for the two different impedance values of the plasma tube, before and after breakdown. Yet another function of the matching network is to cancel reactive components at source and load. U.S. Pat. No. 4,455,658 by Sutter, U.S. Pat. No. 4,169,251 by Laakmann and U.S. Pat. No. 4,363,126 by Chenausky et al. are typical examples of such interconnect systems. An exception to these standard techniques is taught by Laakmann in U.S. Pat. No. 4,837,772. In this disclosure a lumped constant matching system is used directly between the RF generator's output stage transistors and the laser. No interconnect cables are used, for reasons disclosed there. However, the main feature of that disclosure is the "self-oscillating technique" that eliminated much of the complexity of matching drive frequency and laser as well as accounting for the two different impedance states of the plasma contained within the laser's plasma tube. In U.S. Pat. No. 4,373,202 by Laakmann, et al., the technique is disclosed of using a 75 ohm quarter wave transmission line within a 50 ohm system to automatically adjust power in order to decrease "hot spots" within the plasma tube and provide a more stable discharge. However, both laser and power source are still matched to 50 ohm impedances and produce sinusoidal waveforms. SUMMARY OF THE INVENTION The present invention provides a matching system between a source of RF energy and a laser tube which is simple in design while also providing a very good match. In general, the invention is an RF excited gas laser system. The laser system comprises a plasma tube, a voltage source of RF energy, and a transmission line. The plasma tube has an electrical input port, a discharge section and means for outcoupling laser energy. The plasma tube produces laser energy upon ignition of a gas contained within the plasma tube. The input terminal has a real impedance at a predetermined operating frequency. The voltage source of RF energy has a source impedance much lower than the plasma tube impedance at the operating frequency. The transmission line is connected at an input end to the voltage source and at an output end to the plasma tube. It has an electrical length substantially equal to an odd number of quarter wavelengths at the operating frequency and has a characteristic impedance (with the plasma ignited) intermediate the impedance of the voltage source and the impedance of the plasma tube. In one embodiment, the drive source of the laser system is balanced and the load due to the laser system is unbalanced. In this case, the transmission line is coaxial and is used to convert from the balanced source to the unbalanced load. In another embodiment, the drive source, transmission line and laser system load are all balanced. In either embodiment the drive source may be a square wave. In a further embodiment, the balanced transmission line comprises two coaxial cables having substantially equal lengths. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a conventional matching network known in the prior art, connected between a gas laser and an RF generator. FIG. 2 is a schematic diagram of the final stage of a conventional RF generator known in the prior art. FIG. 3 is a schematic diagram of a lumped constant matching network known in the prior art. FIG. 4 is a schematic diagram of a first embodiment of the invention, including a quarter wave transmission line connected between a balanced pair of output transistors and an unbalanced laser load. FIG. 5 is a schematic diagram of a third embodiment of the invention, including two quarter wave transmission lines of FIG. 4 and further including a 1:1 isolation transformer. FIG. 6 is a schematic diagram of a second embodiment of the invention, including the quarter wave transmission line of FIG. 4 and further including a 1:1 isolation transformer. DETAILED DESCRIPTION OF THE INVENTION FIG. 1 is a schematic diagram of a conventional matching network 10 known in the prior art, connected between a gas laser and an RF (radio frequency) generator. The matching network 10, which can be grounded to electrical ground 12, has an input 14 and an output 16. The input 14 is connected to an output end of an inner conductor 20 of a transmission line 18. An outer shield 22 of the transmission line 18 is electrically grounded at the transmission line's output end. An input end of the transmission line 18 is connected to an RF source 24. One side of the RF source 24 is connected to the center conductor 20 of the transmission line 18 and the other side of the RF source 24 is connected to the outer shield 22 of the transmission line 18. The output 16 of the matching network 10 is connected to a laser tube 26 of a gas laser. The laser tube 26 includes at least two electrodes 28a and 28b which transversely excite a lasing gas mixture contained within the laser tube 26 through the application of an RF voltage across the electrodes 28a and 28b. FIG. 2 is a schematic diagram including a final stage 30 of a broadband RF source 24 known in the prior art. The final stage 30 operates at 28 volts DC and uses two transistors 32a and 32b operating in a push-pull configuration. The voltage drops due to the transistors 32a and 32b are usually negligible. As is well known in the art, a transformer 34 is used to match the impedance of the final stage 30 to an input 36. The final stage 30 is connected to a matching network 38 within the RF source 24 to match the impedance of the final stage 30 to the desired impedance at the output 40. A 50 ohm output is conventional for an RF generator. FIG. 3 is a schematic diagram of a lumped constant matching network 50 known in the prior art. It represents one way of matching the impedance of a drive transistor 51 to the impedance of the electrode 28a of the laser tube 26. In this laser configuration, the electrode 28b is electrically grounded. The matching network 50 includes inductors 52 and 54 and adjustable capacitors 56, 58 and 60 to perform the desired impedance-matching operation. FIG. 4 is a schematic diagram of a first embodiment of the invention, which provides for simpler impedance matching between a source 24' and a laser or plasma tube 26'. The laser tube 26' differs from the laser tube 26 in that it includes two pairs of electrodes, pairs 70a-70b and 72a-72b. The electrodes are arranged in a square configuration with the electrodes of each pair of electrodes positioned diametrically opposite each other within the laser tube 26'. Electrode 70a is connected to the output of the RF source 24 through the impedance-matching circuit to be described subsequently, and electrode 70b is connected to electrode 70a through an inductance coil 74. Both of electrodes 72a and 72b are electrically grounded. A transmission line 80 is directly connected between the collectors of the transistors 32a and 32b and electrode 70a of laser tube 26'. An outer shield 80a of the transmission line 80 is connected to the collector of transistor 32b and to ground through a blocking capacitor 82 at the laser tube end of the transmission line since it carries DC voltage, as inner conductor 80b of the transmission line 80 is connected to the collector of transistor 32a. The coil 74 shown is disclosed in U.S. Pat. No. 4,837,772. The coil 74 serves the purpose of neutralizing capacitive reactance and generating bi-phase excitation, as explained in said U.S. patent. The transmission line 80 typically has a 50 ohm nominal impedance and has an electrical length of a quarter wave. Accordingly, at the typical excitation frequency of 45 MHz it has a physical length of about 130 centimeters due to the velocity factor of the transmission line's dielectric. The impedance (R) of the electrodes 70a of the laser tube 26' averages about 200 ohms when the laser tube 26' is lit, as disclosed by U.S. Pat. No. 4,805,182. This assumes that the laser tube 26' has a square bore of 4.8 millimeters, contains a laser gas at a pressure of 60 torr and has discharge electrodes that are 37 centimeters long. These laser tube parameters are appropriate for a gas laser operating at resonance with an input power of about 110 W. In a CO 2 laser this corresponds to a continuous wave (CW) laser output power of about 15 W. This value of the impedance R corresponds to an electrode-to-electrode impedance of 800 ohms. The impedance of the discharge section of the laser tube 26' is several thousand ohms in the non-ignited state. (These impedances are measured unsymmetrically.) However, the impedance R depends on power delivered. It is lower with higher input power. The input power of 110 W corresponds to the maximum laser output power. In a second aspect of the invention, the signal driving the pair of transistors 32a and 32b is derived from a crystal controlled or variable frequency generator through a transformer 84, as shown in the schematic diagram of FIG. 6. It may also be derived by connecting a feedback path between laser tube 26' and an input 86 as taught by U.S. Pat. No. 4,837,772. The transistors 32a and 32b can be operated in class B or AB to produce near sinusoidal voltage outputs with negligible saturation drops as is well known in RF amplifier design. The collector-to-collector RMS voltage between the transistors 32a and 32b is therefore essentially two times the supply voltage and the required load resistance to deliver a power P is R=V 2 /P. For the indicated parameters this load resistance is 14.3 ohms. As is well known in the art, a quarter wave transformer to match the two impedances must have characteristic impedance (Z) equal to the geometric mean of Z/r=R/Z. According to the theoretical load relationship given above, to deliver 110 W, the push-pull stage has peak-to-peak output voltage of 56 V or 39.5 V RMS. The corresponding load impedance is 14.3 ohms. Thus, the impedance Z of a quarter wave line to match the two impedances has to satisfy the expression: Z/14.3=200/Z. An impedance Z of approximately 53 ohms satisfies this. This is close enough to standard values of transmission lines (approximately 50 ohms) to make this invention realizable. For the indicated parameters, this value of impedance Z calculates to 53 ohms. This is a very fortunate circumstance as this value is close enough to the value of commercial cables which range between 50 and 53 ohms for most popular sizes. This matching technique then provides further simplification of the already low production cost of the "all-metal" laser technology disclosed in U.S. Pat. No. 4,805,182 and the simple "self oscillating" excitation technology disclosed in U.S. Pat. No. 4,837,772. Contrary to prior art disclosed in U.S. Pat. No. 4,373,202 by Laakmann, the quarter wave transmission line 50 is used between the RF source 24 and the laser tube 26'. The RF source 24 is represented by the alternately saturated transistors 32a and 32b. Indeed the drive does not have to be a sine wave. The transistors 32a and 32b can be operated in a square wave fashion. Referring to Table 1, no power is delivered to the laser tube 26' or to the transmission line 50 at any odd harmonic. This is so because the laser drive impedance is zero at all frequencies except at the fundamental. The interconnect transmission line 50, however, represents a odd multiple of a quarter wave lengths for all harmonics. Such lines have the same property as a quarter wave transmission line. When terminated with a short, their input impedance is infinite. Therefore no current is delivered to the input of the transmission line 50 (as seen by the transistors 32a and 32b) at any of the harmonics. This represents an ideal load for the transistors 32a and 32b and accounts for the observed high efficiency of this invention. Collector efficiency is a theoretical 100 percent compared to a theoretical 78 percent for class B linear amplifiers. Observed efficiencies are about 75 percent versus 50 percent in the class B amplifiers of the prior art. TABLE 1______________________________________Square Wave Drive Amplitude TransmissionHarmonic x Line Length Laser Transistor(n) 2 VCC λ Impedance Load______________________________________1 4/π 1/4 200 ohms 14.3 ohms3 4/3π 3/4 very low very high5 4/5π 5/4 very low very high______________________________________ The Fourier expansion of a square wave shows terms of 4/nπ where n is the harmonic number. If the drive system is used in a near square wave mode, the fundamental RMS voltage for perfect transistors 32a and 32b and the RF source 24 is 56/√(2)×4/π=50.4 V. Again solving for the load resistance to deliver 110 W results in r=V 2 /P=23 ohms. Accordingly, a matching quarter wave transmission line has an impedance of 67.8 ohms. This is close to the impedance of a standard 75 ohm transmission line. Alternately, if a 75 ohm transmission line is used between the 200 ohm load and the switching supply, a power of 90.7 W would be delivered to the laser tube. For a 50 ohm transmission line the power delivered is 203 W. As pointed out earlier, the impedance of the laser tube 26' decreases with increased power. The actual power delivered to a laser tube 26' would be below the actual power that is delivered to a resistive load. Thus, there are enough variables between choices of transmission line 80, waveshape, supply voltage and laser operating conditions to build practical systems over a wide operating range. The system diagrammed schematically in FIG. 4 uses the transmission line 80 to go between a balanced system (the push-pull transistor pair 32a and 32b) and a ground reference load represented by the laser tube 26'. This is possible since the common mode impedance of a quarter wave transmission line is several hundred ohms at the operating frequency, particularly when coiled up to fit within the laser enclosure. It was not necessary to wind the transmission line 80 around magnetic materials as is done for broadband transmission line transformers well known in the art. Such a transmission line represents a source of radiation that can result in interference to other instruments or communications systems. The transmission line 80 should therefore only be used within a shielded enclosure. FIG. 5 is a schematic diagram of a third embodiment of the invention, including two quarter wave transmission lines of FIG. 4 and further including a 1:1 isolation transformer. The circuitry shown schematically in FIG. 5 is identical to that shown in FIG. 4 except that the inner conductors of the conventional separate quarter-wave transmission lines 81a and 81b are connected to transistors 32a and 32b, respectively. The outer conductors of the transmission lines 81a and 81b are grounded. The outputs of the quarter-wave transmission lines 81a and 81b are respectively connected to the electrodes 70a and 70b in the laser tube 26'. The electrodes 70a and 70b are connected together via coil 74. The two transmission lines 81a and 81b have substantially equal lengths. If desired, the transmission lines 81a and 81b can be packaged together in a single cable. FIG. 6 shows a method of overcoming the radiation problem of the embodiment of FIG. 4 by using a balanced to unbalanced (balun) type transformer 85. As is well-known in the art, such transformers can be built very effectively for unity transformation. Such is not the case for step-up or step-down transformers. A typical implementation uses twisted wire wound around a high permeability ferrite core, which is usually toroidal. The close physical proximity and core permeability assure a nearly perfect transformer, particularly for this uncritical narrow band application. The transmission line 80 in this case can be used as an interconnect between shielded enclosures without causing much radiation. All of the advantages and considerations discussed above apply. A distinct advantage of the disclosed laser system is the ease of laser tube breakdown. The laser tube 26' initially has a high impedance. The drive frequency injected into the input 86 has a frequency close to resonance of the laser tube 26'. The high laser tube impedance is reflected to a very low impedance, typically a few ohms by the inverse transformation property of the quarter wave transmission line 80. The RF source 24 is a voltage source that will cause very high current to flow until breakdown is achieved in the laser tube 26', particularly when operated in square wave fashion. In this context, the definition of a voltage source is one of very low source impedance, when compared to the applied load. The instantaneous peak currents for a few microseconds are far above CW conditions. The amount of power delivered is likewise high. Breakdown is achieved within a few microseconds. After breakdown has occurred, power will self-regulate as taught in U.S. Pat. No. 4,373,202. The high peak currents seen by the transistors 32a and 32b are combined with correspondingly low collector voltages. This is relatively safer than the situation in the prior art when the power delivered during firing is usually less due to mismatch, with high peak voltages on the transistors. The matching system of this invention has also significantly reduced the incidence of the yet unsolved "dark" effect, where a laser may take several seconds to fire initially after prolonged shut down. This extremely simple technique has accomplished the following: (1) Very few parts are necessary in comparison to the existing state-of-the-art designs. Additionally there are no matching adjustments. (2) The quarter wave transmission line 80 is driven by a voltage source, as represented by the two alternately saturated output transistors 32a and 32b. Extremely high voltages are delivered to the discharge section of the laser tube 26' to accomplish fast breakdown of the laser gas. This helps to produce high speed pulsing as well as to overcome starting difficulties after prolonged shutdown. RF power delivered is highest just prior to breakdown of the gas. In the prior art the RF power delivered is usually less during the ignition phase due to mismatch of the 50 ohm system used. (3) Automatic power compensation improves discharge stability, as disclosed by U.S. Pat. No. 4,373,202. (4) Electrical losses are minimal due to the absence of conventional matching networks. Electrical efficiency is about 15 percent better than prior art as described in U.S. Pat. No. 4,837,722. Additional gains in efficiency are the result of using the transistors 32a and 32b as switches, as will be explained in (6) below. (5) The system 10 can be used with conventional fixed frequency excitation, as well as in a "self-oscillating" scheme as described in U.S. Pat. No. 4,837,772. (6) The transistors 32a and 32b can be operated in a switching or deep saturation mode with very high efficiency of conversion to sine wave power at the laser tube 26'. This is due to the unique combination of elements when used with the harmonics of a square wave driving voltage. Therefore, no power is delivered by the transistors 32a and 32b except at the fundamental frequency. Those who are skilled in the art may perceive certain modifications such as changes of active devices, transformer, construction of transmission lines, or other circuit elements, including analogy between series and parallel resonance as taught by U.S. Pat. No. 4,837,772. All such modifications are deemed to be within the scope of the invention which is only to be limited by the following claims:

A system for improved drive and matching between an RF power source and a plasma tube in a laser system. The system uses standard 50 or 75 ohm quarter wave transmission lines as the sole interconnect and matching elements between discharge electrodes and drive transistors. The drive transistos may be operated in deep saturation or as switches providing near square wave output to approach the 100 percent theoretical electrical efficiency of switching power supplies. The system features better initial breakdown, bettwer discharge uniformity and power stability under narrow drive pulse conditions, lower matching electrical losses, and extreme simplicity and low cost.

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to two provisional patent Applications Nos. 61/661,619 and 61/661,622 filed on Jun. 19, 2012. The disclosure of the prior applications are incorporated herein by reference. TECHNICAL FIELD The invention generally relates to high volume low speed (HVLS) fans, and more specifically HVLS fans utilizing short take off and landing (STOL) technology. BACKGROUND OF THE INVENTION Interior climate control and air circulation is difficult in certain applications, particularly including large open structural areas such as found in a factory or warehouse setting. This difficulty is encountered in both hot and cold seasonal conditions, where heat during cold weather heating migrates towards the ceiling of a building and humidity tends to migrate down during hot and humid weather conditions. Therefore, there is an interest in forcing air from the ceiling, down, towards an occupied main floor during cooler weather, thus saving costs for heating, and circulating air more generally in warmer weather conditions resulting in a perceived cooler environment due to evaporation. Solutions to these conditions include forced ventilation through ceiling-based plenums in HVAC applications. Another solution is the use of ceiling fans to circulate the ambient air. However, both of these solutions are inadequate for circulating large volumes of air in large open areas such as is common in a factory or warehouse setting. HVLS fans provide improvement over HVAC systems and/or traditional ceiling fans by moving larger volumes of air. These systems have their own limitations including relatively low efficiency in both the amount of energy used and amount of circulated air per unit of energy use. STOL technology is a known solution for allowing aircraft to take off and land within constrained short distances. STOL technology has been adapted to aircraft airfoil profiles for providing improved lift and efficient movement of air under slower take off or landing speeds. Known aircraft wing profiles utilizing STOL design technology include EPPLER-420 and FX63-137 profiles. But, these airfoil profiles utilizing STOL design technology have not been adapted for use in HVLS fan systems. In addition, due to their size and weight resulting from fans reaching diameters from 12 feet to 20 feet, or more, there is risk to persons and equipment below the fan in the event of a failure causing a portion, or all, of the fan to fall. Therefore, there is opportunity and need for improving air circulation systems in large open areas. Further, there is need for improving HVLS fan systems to provide higher efficiencies and maximize airflow in large open spaces such as warehouses, manufacturing facilities, places of worship, gymnasiums/health clubs, auto dealerships and more. There is also a need for providing safety measures in the implementation of HVLS fan systems. SUMMARY OF THE INVENTION AND ADVANTAGES The present disclosure addresses these needs and issues by providing an HVLS fan system incorporating STOL technology in a system that increases air volume and circulation while also increasing efficiencies and which does not add significant costs, weight, or manufacturing complexity to this system. It is therefore an object of the disclosure to take advantage of STOL technology and thus increase efficiency of an HVLS fan system. It is a further object of the disclosure to provide greater efficiency in the movement of air in the HVLS system. It is an additional object of the disclosure to provide an economical and lightweight solution to better circulate air in large areas. Another object of the disclosure is to provide a safety mechanism for preventing injury or damage in the event of a failure in the HVLS fan. The present disclosure provides an HVLS fan system utilizing STOL technology and having better efficiency, including an airfoil form adapted to provide higher airflow at lower circulation rates while decreasing drag on the airfoils and increasing efficiencies. The system also includes an airfoil profile consistent with STOL technology. More particularly, an airfoil utilizing an EPPLER 420 or substantially similar airfoil design. In addition, the system includes a wing tip advantageously formed to reduce drag of the airfoil. Further, the system employs a hub displacing the airfoil at an angle most suitable for maximizing the benefits of the STOL technology. More particularly, this includes a hub providing an attachment angle of between seven and ten degrees to the airfoil, and even more particularly eight degrees to the airfoil. Together, the disclosure provides an HVLS fan system offering improved efficiency, reduced drag, and increased air flow for the benefit of better circulating air in a large open area. In addition, the system includes a safety system including attachment of a retaining member, one for each airfoil, on the hub that passes through a retaining bracket in a manner that in the event of the airfoil becoming dislodged from the hub or the hub itself becoming disconnected from the drive system prevents the hub and/or the airfoils from falling. The retaining brackets do not touch or otherwise notably increase air resistance in the system but provide for an important safety measure where failure can cause catastrophic consequences. Another safety aspect is a series of overlapping brackets which mount on the top of the airfoils which interlock each of the airfoils to the one next to it. This will prevent an airfoil from becoming dislodged from the system in the case of failure. In addition, guy wires connect the frame of the HVLS fan system to a support member such as a ceiling support beam. Other objects and features of the present invention will become apparent when viewed in the light of the detailed description of the preferred embodiments when taken in conjunction with the attached drawings and the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: FIG. 1 is a perspective view of the HVLS fan system of the invention; FIG. 2 is a side sectional view in spaced apart form showing the HVLS fan system of FIG. 1 ; FIG. 3 is a side cross sectional view of an airfoil of the HVLS fan system; FIG. 4 is a top view of an airfoil of the HVLS fan system; FIG. 5 is a side view of a wingtip fence of the HVLS fan system; FIG. 6 is a top view of the wingtip fence of FIG. 5 ; FIG. 7 is a back view of the wingtip fence of FIG. 5 ; FIG. 8 is a top view of a central hub of the HVLS fan system; FIG. 9 is a side view of the central hub of FIG. 8 ; FIG. 10 is a perspective view of a cylinder of the HVLS fan system; FIG. 11 is a cross-sectional view of the cylinder of FIG. 11 ; FIG. 12 is a top view of a securing plate of the HVLS fan system; FIG. 13 is a perspective view a of portion of the HVLS fan system in spaced apart form emphasizing the locations of safety brackets; and FIG. 14 is a table containing X-Y data coordinates for the airfoil profile of the HVLS fan system. DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following figures, like reference numerals are used to identify identical components in the various views and embodiments. The following example is meant to be illustrative of preferred embodiments for the invention. However, those skilled in the art will recognize various additional alternative embodiments. Referring to FIGS. 1-13 , an HVLS fan system 10 of the disclosure includes airfoils 12 coupled at one end to a central hub 14 and extending in the other direction to a distal end having a wingtip fence 16 . The central hub 14 is coupled to a motor 18 for rotating the airfoils 12 . The motor 18 is connected to a frame 20 which is coupled to a lower yoke 22 and an extension bar 24 which in turn is coupled to an upper yoke 26 . The upper yoke 26 is illustrated as connected to a building member 28 such as a girder or other similar structures suitable for bearing the weight of the HVLS fan system. The extension bar 24 as a backup secures the HVLS fan system to the building member 28 with a safety cable 30 . Guy wires (not shown) are also used to secure the frame to weight bearing locations on either the builder member 28 or other support structure in the ceiling of the building. Typically, four guy wires are used and attached at somewhat equally spaced locations around the HVLS fan system. As illustrated, the HVLS fan system has six airfoils 12 equally spaced around the central hub 14 . The HVLS fan system airfoils 12 are generally positioned between ten feet and fifty feet above the floor with optimum height generally between twenty feet and thirty feet. The motor 18 is a standard approximately one horsepower electric motor known to those skilled in the art. To accomplish the objective of HVLS, the airfoils 12 are each between five and twelve feet in length and more preferably between six and ten feet in length. Looking up at an installed HVLS fan system 10 it will rotate in a counterclockwise direction 32 . The airfoils 12 are formed out of a lightweight material such as aluminum or a composite metal that can be formed into an airplane wing type shape with a hollow core. However, it should be appreciated that the airfoils can be formed of a variety of different materials, including plastics, polyurethanes, and other suitably rigid materials adequate to form an airfoil, or even combinations of such materials known to those skilled in the art. It should also be appreciated that the length of the airfoils 12 can be increased or decreased to suit a certain application. In addition, it should be appreciated that the HVLS fan system 10 can include airfoils 12 without inclusion of wingtips fences 16 . Further, motor 18 may be any manner of other suitable motor including suitable horse power or amperage rating know to those skilled in the art. The airfoils 12 are fan blades comprised of a generally elliptical top surface 34 and a generally elliptical bottom surface 36 . The airfoils 12 are configured to mount to the central hub 14 through the use of an H-shaped connector member 37 , connected on one end to the central hub 14 and on the other end to a receptors 39 interior to the airfoil 12 . The airfoil further includes a leading edge 38 and a trailing edge 40 . The trailing edge 40 maintains a radius of approximately 0.043 inches. The airfoil may be a substantially hollow extruded aluminum section of approximately 0.1 inches in thickness when mounted to the central hub 14 including STOL-type airfoils. The wingtip fence 16 has a substantially vertical member 42 with a connecting perimeter 44 defined by the profile of the airfoil 12 , to which it is attached. The wingtip 16 consisting of a lower concave edge 46 , an upper convex edge 48 , a leading 50 and trailing edge 52 which sits flush with the airfoil 12 end edge. The vertical member 42 protrudes rearward relative to the leading edge 50 of the airfoil 12 . The vertical member 42 consists of two planes. The lower plane is parallel to the connection plane of the airfoil and wingtip fence, while the upper plane is angled outward relative to the innermost end of the airfoil. Adding the wingtip fence 16 to the airfoils 12 improves the aerodynamic properties of the airfoils, by reducing drag and therefore increasing the fan's overall efficiency. The wingtip fence 16 includes a mounting member 54 which connects to an inner portion of the receptors 39 of the airfoil 12 . The wingtip 16 is configured to secure the connection to the airfoil 12 through protruding guide points 56 that couple to an inner perimeter of the airfoil 12 thus mounting the wingtip fence 16 to the airfoil 12 . The central hub 14 provides a securing system for the fan assembly, where a bottom frame member 58 is connected to a securing plate 60 by fasteners 62 . The central hub 14 assembly includes a cylinder 64 coupled to the central hub 14 and retaining members 68 , one for each of the airfoils 12 that when connected to the central hub 14 extend through an opening in the securing plate 60 thus providing a safety stop against a failure involving a break in the motor 18 or its coupling to the cylinder 64 or a drive shaft 70 . The cylinder 64 has an opening 72 for receiving the drive shaft 70 . The drive shaft 70 does not connect directly to the cylinder 64 , but instead couples to a bushing (not shown) which couples the drive shaft 70 to the cylinder 64 through simultaneous expansion and contraction, as is known to those skilled in the art. The central hub 14 includes flanges 74 which are displaced from a plane defining the central hub at an angle predetermined for the airfoils 12 . The angle of the flanges 74 positions the airfoils 12 at an angle most suitable for maximizing the benefits of the STOL technology. More particularly, this includes an attachment angle of between seven and ten degrees to the airfoil, and even more particularly eight degrees to the airfoil. Another safety aspect is a series of overlapping brackets including a first bracket 76 and second bracket 78 which mount on the top of the airfoils and interlock each of the airfoils 12 to the one next to it. The first bracket 76 and second bracket 78 are held in place with fasteners 80 . This prevents the airfoil 12 from becoming dislodged from the system in the event of failure. In addition, guy wires (not shown) connect the frame of the HVLS fan system to a support member such as a ceiling support beam. After applicants first conceived that STOL technology would benefit efficiencies and overall performance of an HVLS fan, experimentation was undertaken under preset parameters and requirements to optimize a STOL airfoil profile. This experimentation, undertaken at the request and direction of the applicants by Haiyer Lou, Ph.D, M. Eng at TurboMoni, confirmed that of two airfoil profiles adapting STOL technology an airfoil following EPPLER-420 parameters was more efficient when angled at approximately 8 degrees from horizontal. Thus, referring to FIG. 14 , the airfoils 12 are predetermined to comply with STOL technology and provide high efficiency operation including higher lift and lower drag for the application of an HVLS fan. The EPPLER-420 profile disclosed in FIG. 14 provides dimensionless cord lengths that provide for defining X-Y coordinates by multiplying with the real cord (the distance from leading edge point to the trailing edge point). Thus, an HVLS fan system of the invention, including its various embodiments, provides a high efficiency cost effective, secure means of addressing and providing air movement in large open areas. While particular embodiments of the invention have been shown and described, numerous variations and alternative embodiments will occur to those skilled in the art. Accordingly, it is intended that the invention be limited only in terms of the appended claims.

An HVLS fan system uses STOL technology for airfoils and angle of attack thus optimizing air movement efficiency and reducing drag. The HVLS fan system includes wingtip fence end caps to the airfoils for improving efficiency by reducing drag. The HVLS fan system also includes an interconnection of the airfoils to a securing plate thus providing a failsafe and reduced potential for damage or injury resulting from failure of the connection between the airfoil array and a drive unit such as an electric motor and associated gearing.

[0001] The present invention relates to a composition, which contains several kinds of components beneficial to human eye health, and provides supplements for indispensable materials such as lutein, zeaxanthin, zinc, and selenium necessary for human eyes. BACKGROUND [0002] Eye health is a permanent and important topic. The focus on eye health has never stopped. Currently, various eye protection products are present on the market. People have been trying to prevent or treat all kinds of eye discomfort or ophthalmic disease, such as asthenopia, amblyopia, myopia, cataract, age-related macular degeneration (ARMD) and the like, and keep eyes healthy by absorbing or using some natural or synthetic substances or some trace elements. Although the effects of using these products are different, people have not stopped to seek for the optimal medical compositions to achieve the best effect on eye protection. [0003] Among all of eye protection components, lutein and zeaxanthin are two very important substances. Lutein and zeaxanthin are natural carotenoids which widely exist in vegetables, flowers, fruits and some algae living creatures. They are widely used in many fields such as food, health products, cosmetic products, medicine, tobacco, feed for animals and poultries. Recently researches have found that lutein and zeaxanthin not only have a close relationship with a disease of age-related macular degeneration (ARMD), but also can effectively prevent from visual failure. Lutein and zeaxanthin are two only carotenoids existing in the human retina, which are selectively deposited in the macular region and the whole retina, generally there is the highest density around the macular fovea and a gradually decreased density around the retina. These macular pigments are able to effectively prevent from occurrence of the oxidation reaction in the retina. It can be assumed that an effective method of treating and preventing the macular degeneration or injury is to supplement lutein and zeaxanthin. Furthermore, lutein and zeaxanthin can be used to improve the visual efficacy in the absence of ARMD, for example, there are some good healthcare functions for the juvenile myopia, senile blindness caused by muscle degradation, and the eye damage caused by the ultraviolet radiation from sunlight and computer. A lot of clinical testing results show that the amount of recommended ingestion of lutein and zeaxanthin for human body is 6 mg per day. It is generally thought that the acceptable daily intake (ADI) of lutein crystal is 25 mg/person/day, which can not result in the carotenoid yellow dermatosis. [0004] More and more people are interested in the special physiological functions of lutein and zeaxanthin. Currently, a large amount of health food and fortified food containing the above-mentioned two natural pigments have present abroad. The FDA of USA approved the use of lutein and zeaxanthin as food supplement agents in foods in 1995 to improve nutritive values, for example, the use in beverage to be beneficial for eyesight and in infant food. At the end of 2006, the use of lutein as coloring agent in beverage, baked food, frozen food, and food such as fruit jelly and fruit jam with the addition amount of 50˜150 mg/kg, has been also approved in China. In the meanwhile, the use of lutein as nutrition enhancement agent has been approved as well. The impetus of new market makes the market value of lutein reach 139 million dollars in 2004, but only 64 million in 1999. The tendency of this strong increasing is still continued, and BBC thinks that the increasing rate will reach 6.1% every year by 2009. [0005] In addition to lutein and zeaxanthin, other substances such as zinc and selenium are beneficial to eye health. Studies show that zinc can increase sensitivities of optic nerves, and is the main component of the retinal reductase in the retinal cells. The enhancement of zinc can directly affect synthesis and metabolism of xanthopsin from vitamin A, which may be helpful for the effect of retinal, thereby to increase human adaptability to weak light. The lack of zinc may also affect the ability of retinal cell to distinguish from colors. Selenium is an important trace element to maintain eyesight, and is the main component of glutathione peroxidase. The lack of selenium may lead to amblyopia. Accordingly, the carophylls such as lutein, zeaxanthin and zinc, selenium are good partners. The combination of the four components has the effects on promotion enhancement, and has effects on protection of eyes, prevention of juvenile myopia, sthenopia among workers and senile visual failure. [0006] In view of further attention to eye health and the aforementioned identification for eye protection function, foods including lutein or selenium or zinc or three of them, such as beverage, milk, yoghurt, and the like, have also present in the market, but the function or addition of zeaxanthin have been generally ignored in these products. Actually, in some sense, zeaxanthin has the same, or even better, eye protection effects as lutein. For example, at the macular of the human retinal central, the content of zeaxanthin is generally about two times of that of lutein. The nearer the edge of the retinal is, the higher the content of lutein is, and the relatively lower the content of zeaxanthin is. At the most edge of the retinal, the content of lutein is about three times of that of zeaxanthin, in the human plasma, the content of lutein is also about three times of that of zeaxanthin, it shows that there is a transfer mechanism from lutein to zeaxanthin in human body. Meanwhile, other studies also found that some of lutein ingested in by human body will change into zeaxanthin. Accordingly, zeaxanthin plays non-negligible roles in eye health of human. The results of our preliminary test in human body also proved that visual performances of human eyes, especially visuognosis persistence and eye consciousness symptoms may be well improved, when being supplemented with the mixture of lutein and zeaxanthin added with selenium and zinc. [0007] As described above, there are various eye protection products in the market, however, most of them are compositions containing one, or two, or three components of the four. For example, CN1625395A relates to the composition of lutein and zeaxanthin used for glare protection; CN1253091 relates to a dairy product or beverage to be beneficial for eyesight containing lutein, zinc and selenium; US2005/0147648 keeps eyes healthy by supplementing a combination of zeaxanthin, polyunsaturated fatty acids, plant extracts and the like; U.S. Pat. No. 7,267,830 relates to the objective of improving eye health level by supplementing carotenoids and vitamin A, C, DHA and some trace elements, wherein in the disclosed formulation, the proportion of lutein and zeaxanthin is kept at the level of 3:1, and the function of zeaxanthin is not specially mentioned; U.S. Pat. No. 7,282,225 supplements vitamin A, C, E, carotenoids (beta-carotenoid, lutein, zeaxanthin), trace elements by dietary to improve visual performance and acuity, but the unique effect of zeaxanthin on improving visuognosis persistence is not highlighted in this formulation. [0008] The present invention provides a composition containing the aforementioned four components in a certain proportion. Such composition provides trace elements for human eye health, such as lutein, zeaxanthin, zinc, and selenium, and is conducive to human eye health, and is especially beneficial for the improvement of visuognosis persistence of human eyes, for the asthenopia remission, and improvement of eye consciousness symptoms. SUMMARY [0009] Lutein and zeaxanthin are the only two kinds of carotenoids existing in the human retina, which are closely related to the macular degeneration. Zinc and selenium can increase adaptabilities to weak light and color distinguishing ability of human eyes. The compositions containing the aforementioned four substances in a certain proportion are beneficial for human eye health when being used in formula food. The objective of the present invention is to describe the formula food including the composition described above. [0010] As used herein, the term “visual performance” is referred to as visual function such as acuity, contrast sensitivity, glare recovery, dark adaptation, visuognosis persistence, light stress recovery and color vision and the like, wherein special attention is the increase of visuognosis persistence, such as asthenopia remission and improvement of eye consciousness symptoms. [0011] As used herein, the term “visuognosis persistence” is an index for evaluating asthenopia. When the cortical excitability in the human brain reduces, the visual analysis function decreases, in the process of eyes fixating at object, invisible duration will increase and visuognosis duration will decrease. The percentage of visuognosis duration to fixation duration is referred to as visuognosis persistence, which is an index to comprehensively reflect the visual performance and psychological function. The visuognosis persistence (%)=visuognosis duration/total fixation duration* 100. [0012] As defined herein, “formula food” is referred to as various foods for enhancing certain nutritional function, such as formula milk powder, including infant formula milk powder or senile formula milk powder and the like; various functional beverages such as beverages containing milk, orange juice beverages, coke, carbonated beverages, suspended beverages, and so on; baked food such as cakes, biscuits and so on, and, etc. including various dietary supplement tablet, capsule for nutrition supplements. [0013] The present invention provides a formula food beneficial for eye health, comprising lutien, zeaxanthin, zinc, and selenium. [0014] As defined herein, “eye health” is referred to as good effect of increasing of visuognosis persistence and asthenopia remission and improvement of eye consciousness symptoms as well as preventing from or treating Age-related Macular Degeneration (ARMD). [0015] Wherein, the zinc is inorganic zinc salt or organic zinc salt. The inorganic zinc salt is zinc sulfate or zinc sulfite; the organic zinc salt is zinc orotate or zinc ascorbate. [0016] The selenium is inorganic selenium salt or organic selenium salt. The inorganic selenium salt is selenophosphate, or selenite. The organic selenium salt is selenoamino acid or selenium yeast or selenium-enriched yeast. Wherein, the selenophosphate is sodium selenophosphate; the selenite is sodium selenite or sodium selenate; the selenoamino acid is L-selenomethionine; the selenium yeast or selenium-enriched yeast is Brewer's yeast or Barker's yeast. [0017] Wherein the amount of the lutein added in the formula food is 0.3˜250 mg/kg. The amount of the zeaxanthin added in the formula food is 0.3˜250 mg/kg. Preferably, the amount of the lutein added is 2.0˜80 mg/kg in the formula food; the amount of the zeaxanthin added is 2.0˜80 mg/kg in the formula food. The proportion of mass of lutein and zeaxanthin is in the range of 0.05:10.0˜10.0:0.05. Preferably, the proportion of mass of lutein and zeaxanthin is in the range of 0.1:2.0˜2.0:0.1. More preferably, the proportion of mass of lutein and zeaxanthin is in the range of 0.1:2.0˜1.0:1.0. In particular, the lutein and zeaxanthin of the present invention may be obtained by mixing in a certain proportion, that is, they have been mixed in a certain proportion before the dosage available in preparation to add into the formula food is obtained. One of the mixing proportions of lutein and zeaxanthin is in the range of 0.05:1.0˜1.0:0.05. [0018] Wherein the amount of zinc added in the formula food is 4˜80 mg/kg which is based on the weight of pure zinc when the added zinc is organic or inorganic zinc. The amount of selenium added in the formula food is 30˜350 μg/kg which is based on the weight of pure selenium when the added selenium is organic or inorganic selenium. [0019] Wherein the lutein exists in the form of crystalloid or aliphatic ester is extracted from natural sources. The dosage form of the lutein added is microencapsulated powder, or homogeneously dispersed in edible vegetable oils, or aqueous dispersible emulsion Wherein the mass percent of the lutein in the corresponding dosage form is 1˜25 wt %. [0020] Wherein the zeaxanthin exists in the form of crystalloid or aliphatic ester is extracted from natural sources or obtained by chemical synthesis. The dosage form of the zeaxanthin added is microencapsulated powder, or homogeneously dispersed in edible vegetable oils, or water dispersible emulsion. Wherein the mass percent of the zeaxanthin in the corresponding dosage form is 1˜25 wt %. [0021] Wherein the formula food further contains at least one antioxidant, including synthetic tocopherol (vitamin E), natural tocopherol (natural vitamin E), sodium D-ascorbate (sodium iso-VC), ascorbic acid (vitamin C), ascorbyl palmitate, phosphatidylcholine. [0022] Wherein the formula food is applied in various formula milk powder, various functional beverages, various baked food, various dietary supplement tablet and capsule. In particular, the formula food can be used in various food for the purpose of enhancing certain nutritional function, such as formula milk powder, including infant formula milk powder or senile formula milk powder and the like; various functional beverages like beverages containing milk, orange juice beverage, coke, carbonated beverage, suspended beverage, and so on; baked food like cakes, biscuits and so on, and various dietary supplement tablets, capsules and so on for the purpose of nutrition supplement are included as well. [0023] In the present invention, the suitable dosage form of the lutein, zeaxanthin, zinc and selenium to be added should be dissolved in water or oil in advance, and then added during the suitable step of formula food processing. [0024] The addition of the components as described above will not affect the initial taste in the scope of the present invention. [0025] Within the scope of the present invention, the composition of the four substances mixed in a certain proportion can be made into soft capsules or hard capsules or tablets for oral administration thereby achieving the objective of diet supplementing. [0026] In addition, a certain amount of antioxidant such as synthetic tocopherol, natural tocopherol, ascorbyl palmitate, phosphatidylcholine and so on may be added into the composition, or into the single component dosage of lutein, zeaxanthin, zinc, selenium. [0027] The beneficial effect of the present invention is supplementing the mixture of lutein, zeaxanthin, zinc, selenium, and properly increasing the amount of zeaxanthin relative to lutein to improve the effect of the composition on asthenopia remission and improvement of eye consciousness symptoms. The formula food of the present invention is beneficial for human eye health, in particular, for the increase of visuognosis persistence and asthenopia remission and improvement of eye consciousness symptoms. BRIEF DESCRIPTION OF THE DRAWINGS [0028] FIG. 1 shows the changing rate of visuognosis persistence after feeding trails for the subjects from different test groups; and, [0029] FIG. 2 shows the percentage of the subjects whose visual fatigue is ameliorated in respective test group. DETAILED DESCRIPTION [0030] The features of the present invention will be more clearly understood by reference to the following embodiments, which are not to be construed as limiting the present invention. EXAMPLE 1 Asthenopia Remission Test of Lutein, Zeaxanthin, Zinc, Selenium [0031] 278 subjects, ranging in age between 17-23 years old, who use video display terminals (VDT) for long time and tend to have asthenopia, were selected for this test according to the voluntary principle, with the exception the following subjects: those who have certain ophthalmic disease that may affect the testing results; those who have administered the relevant drugs, health products or applied the other treatments for long or short time that may affect the determination for the results; those who do not confirm to the inclusion criteria, and do not feed the tested drug according to regulations, or have incomplete information and the like that may affect performance or safe-determination. [0032] Control group and test group were established in the test, wherein 48 subjects were randomly selected to administer placebo in control group. The test group was further divided into five groups (I, II, III, IV, V), 46 subjects for each group. The subjects in each test group were successively treated with drug compositions in the form of tablets for 35 days, once per day, two tablets once. The test is adopted for the comparison before and after treatment as well as the comparison among groups. [0000] TABLE 1 Groups Of Human Test And Compositions Of Feeding Tablets Groups Compositions of feeding tablets Control group Placebo Test group I 12 mg lutein Test group II 9 mg lutein and 3 mg zeaxanthin Test group III 4 mg lutein and 8 mg zeaxanthin Test group IV 9 mg lutein, 3 mg zeaxanthin, 27 mg zinc and 120 μg selenium Test group V 4 mg lutein, 8 mg zeaxanthin, 27 mg zinc and 120 μg selenium [0033] 1. Except the active ingredients shown in the formulation, in which the lutein was CarolGold™ 10% TAB; zeaxanthin was CarolZea™ 10% TAB; zinc was zinc ascorbate; selenium was selenoamino acid like L-selenomethionine; the others were necessary for tablets, such as hydroxymethylcellulose, modified starch, and the like. The total weight of the tablet was 450 mg. [0034] 2. The appearance, color and weight of placebo tablet were the same as those of feeding tablet. [0035] Each index, including physiological index and functional index, was tested once at the beginning and end of the feeding test. Physiological index includes general physical examination, blood, urine, stool routine examination, blood biochemical criterion examination, type-B ultrasound, chest X-ray, and other corresponding examinations like electrocardiographic examination. Functional index includes ocular symptom examination: Inquiring the case history, and observing the subjective symptom of eyes, for example, eye swelling, ophthalmalgia, photophobia, visual blurring, eye dryness and the like. Aggregate the score before and after feeding according to symptoms degree (3 points as severe symptom, 2 points as moderate symptom, 1 points as mild symptom), and calculate the symptom improvement rate according to the improvement of the main symptom (1 point as effective improvement for each symptom, 2 points as obvious improvement). Detection of visuognosis persistence: the percentage of visuognosis duration to fixation duration is referred as visuognosis persistence. The detection duration is 3 min, and the average value of two detections was taken. [0036] Data processing: data were analyzed by using the statistical software STATE6.0. Paired t test was used for self-control data, and group t test was used for comparison between the mean values of two groups. The later one needs homogeneity test for variance to do suitable variable transformation for the data with non-normal distribution or variance non-homogeneity until the normal variance homogeneity is met, and then the transformed data is used for t test; if the transformed data could not meet the normal variance homogeneity, t test or rank-sum test is used; but for the data whose coefficient of variation is too large, for example, CV>50%, the rank sum test should be used. X 2 test was used for performance indexes. [0037] The change of visuognosis persistence for control and test groups after feeding is shown in FIG. 1 . The visuognosis persistence for subjects in test group was remarkably improved after feeding compared with that before feeding (P<0.05), wherein, it increased 10.27±8.56% for those supplemented with lutein only; the improving extent varied depending on the proportion of lutein to zeaxanthin when the mixture of lutein and zeaxanthin was supplemented, for example, under the condition that the total amount is constant, the visuognosis persistence increased 14.56±10.21% for those supplemented with lutein and zeaxanthin in the proportion of 3:1 and 18.23±7.25% for those supplemented with lutein and zeaxanthin in the proportion of 1:2. There is remarkably difference between the two (P<0.05). When supplemented with a certain amount of trace elements zinc, selenium, the visuognosis persistence of subjects is further promoted, and even the improving extent are more obvious when the proportion of lutein and zeaxanthin was lower(P<0.01). [0038] It can be seen the visual improvement effect from the index of subjective symptom of eyes (clinical symptom score, refer to FIG. 2 ). That is, the results before and after feeding have statistical significance (P<0.001). Furthermore, when supplemented with the mixture of lutein, zeaxanthin, zinc, selenium, in which the content of zeaxanthin was higher than that of lutein, the highest total efficiency was up to 59.45%, which was remarkably different (P<0.05) from that when the content of lutein was higher (total efficiency was 47.27%). [0039] The results of general physical examination, blood biochemical criterion examination, urine routine examination for control group and test group were within the normal range before and after feeding. The results of chest fluoroscopy, electrocardiographic, abdominal examination by type-B ultrasound, chest x-ray for control group and test group were within the normal range before and after feeding. [0040] The test proves the advantages of the present invention, that is, supplementing the mixture of lutein, zeaxanthin, zinc, selenium, and properly increasing the amount of zeaxanthin relative to lutein can improve the effect of the composition for asthenopia remission and improvement of eye consciousness symptoms. EXAMPLE 2 The Eye Health Beverage Containing Lutein, Zeaxanthin, Zinc, Selenium [0041] The beverage contained sugar, citric acid, sodium citrate, vitamin B, lutein, zeaxanthin, zinc, selenium, plant extracts, and the like. Based on the total amount of 1000 g, 60 mg lutein, 0.3 mg zeaxanthin, 40 mg zinc, 30 μg selenium are contained thereinto, other components and water are also included. Certain amount of synthetic tocopherol was used as antioxidant. The used lutein was in the form of 5% CWS-B beadlet, and zeaxanthin was in the form of 5% CWS dry powder. The zinc was zinc orotate and selenium was L-selenomethionine. [0042] The beverage was tested through human test according to the test design similar to that of Example 1, and the results are shown in Table 2. [0000] TABLE 2 The Comparison Of Change Of Visuognosis Persistence In Two Groups After Feeding With Eye Health Beverage (X ± S, %) Groups Before feeding After feeding Promoted percentage Test 53.26 ± 7.87 68.48 ± 6.98 15.26 ± 9.54*** ### group (n = 54) Control 52.35 ± 8.01 53.47 ± 4.98 1.12 ± 4.55*     group (n = 54) [0043] Self-comparison before and after feeding, ** P<0.05, *** P<0.001, Comparison between test group and control group after feeding, ### P<0.001 EXAMPLE 3 The Infant Formula Milk Powder Containing Lutein, Zeaxanthin, Zinc, Selenium [0044] Besides conventional carbohydrate, fat, protein, vitamins A, D, E, K, B, trace elements, oligosaccharide, the infant formula milk powder further contained components beneficial for eye health like lutein, zeaxanthin, zinc, selenium. Based on the total amount of 1000 g, 0.3 mg lutein, 60 mg zeaxanthin, 4 mg zinc, 150□μg selenium are contained thereinto. The used lutein was in the form of 1% CWS dry powder, and zeaxanthin was in the form of 5% CWS dry powder. The zinc was zinc sulfate; selenium was Baker's yeast rich in selenium; and natural tocopherol was antioxidant. [0045] The formula milk powder was tested through human test according to the test design similar to that of Example 1, and the results are shown in Table 3. EXAMPLE 4 The Milk-Containing Beverage Containing Lutein, Zeaxanthin, Zinc, Selenium [0046] The beverage contained sugar, whole milk powder, sodium citrate, vitamin B, stabilizer, lutein, zeaxanthin, zinc, selenium, and the like. Based on the total amount of 1000 g, 250 mg lutein, 12.5 mg zeaxanthin, 80 mg zinc, 180 μg selenium, certain amount of ascorbyl palmitate are contained thereinto, other components and water are also be included. The used lutein was in the form of 10% CWS-B beadlet, and zeaxanthin was in the form of 1% CWS dry powder. The zinc was zinc orotate and selenium was sodium selenophosphate. [0047] The beverage was tested through human test according to the test design similar to that of Example 1, and the results are shown in Table 3. EXAMPLE 5 The Formula Milk Powder for Middle-Aged Persons and Old People Containing Lutein, Zeaxanthin, Zinc, Selenium [0048] Besides conventional carbohydrate, fat, protein, vitamins A, D, E, K, B, trace elements, oligosaccharide, the formula milk powder contained components beneficial for eye health like lutein, zeaxanthin, zinc, selenium. Based on the total amount of 1000 g, 12.5 mg lutein, 250 mg zeaxanthin,40 mg zinc, 350 μg selenium and a suitable amount of phosphatidylcholine are contained thereinto. The used lutein was in the form of 1% CWS dry powder, and zeaxanthin was in the form of 5% CWS dry powder. The zinc was zinc sulfate; selenium was sodium selenate. [0049] The formula milk powder was tested through human test according to the test design similar to that of Example 1, and the results are shown in Table 3. EXAMPLE 6 The Bread Containing Lutein, Zeaxanthin, Zinc, Selenium [0050] Besides conventional plain and strong flour, sugar, butter for stirring, yeast, certain amount of bread improver, the formula bread contained components beneficial for eye health like lutein, zeaxanthin, zinc, selenium. Based on the total amount of 1000 g, 54.7 mg lutein, 19.4 mg zeaxanthin, 60 mg zinc, 150 μg selenium and a proper amount of sodium D-ascorbate are contained thereinto. The used lutein was in the form of 10% CWS dry powder, and zeaxanthin was in the form of 12% CWS dry powder. The zinc was zinc sulfite; selenium was selenium-enriched Brewer's yeast. The obtained breads have uniform fabric, golden yellow color and flavor taste. [0051] The formula milk powder was tested through human test according to the test design similar to that of Example 1, and the results are shown in Table 3. EXAMPLE 7 The Fruit Jelly Containing Lutein, Zeaxanthin, Zinc, Selenium [0052] Besides conventional fruit jelly gel, sugar, calcium lactate, citric acid, the formula fruit jelly contained components beneficial for eye health like lutein, zeaxanthin, zinc, selenium, and was also added with certain amount of mixed tocopherol, sodium iso-VC. Based on the total amount of 10000 g, 15.0 mg lutein, 1.4 mg zeaxanthin, 40 mg zinc, 250 μg selenium are contained thereinto and ascorbic acid was used as antioxidant. The used lutein was in the form of 25% dry powder, and zeaxanthin was in the form of 5% CWS dry powder. The zinc was zinc orotate; selenium was sodium selenite. The obtained fruit jellies had attracting, lucid, and transparent color. [0053] The formula milk powder was tested through human test according to the test design similar to that of Example 1, and the results are shown in Table 3. EXAMPLE 8 The Soft Gelatin Capsule Rich in Lutein, Zeaxanthin, Zinc, Selenium [0054] Based on the weight of 200 mg per soft capsule, the following components are included: 12 mg aliphatic ester of lutein, 2 mg zeaxanthin, 10 mg vitamin E, 15 mg vitamin C, 3.6 mg zinc orotate, 24 μg sodium selenite, 18 mg phosphatidylcholine, 30 mg soybean oil, wherein the used aliphatic ester of lutein has the concentrate 20.0% OS and the zeaxanthin was in the form of 25% OS. [0055] The soft gelatin capsule was tested through human test according to the test design similar to that of Example 1, and the results are shown in Table 3. EXAMPLE 9 The Soft Gelatin Capsule Rich in Lutein, Zeaxanthin, Zinc, Selenium [0056] Based on the weight of 200 mg per soft capsule, the following components are included: 3.6 mg lutein (80 mg/kg), 12 mg zeaxanthin, 8 mg vitamin E, 10 mg vitamin C, 1.8 mg zinc orotate, 32 μg sodium selenite, 24 mg phosphatidylcholine, 21 mg soybean oil, wherein the used aliphatic ester of lutein has the concentrate 25% OS and the zeaxanthin was in the form of 20% OS. [0057] The soft gelatin capsule was tested through human test according to the test design similar to that of Example 1, and the results are shown in Table 3. [0000] TABLE 3 The Changing Rate Of Visuognosis Persistence After Feeding Among Different Groups Test groups Control groups No. of Average changing No. of Average changing Examples subjects rate (%) subjects rate (%) Example 3 21 25.98 ± 8.79* 19 5.87 ± 2.40 Example 4 22  8.98 ± 1.56** 23 −1.51 ± 0.46   Example 5 24  14.06 ± 2.85** 21 3.78 ± 1.58 Example 6 19 12.23 ± 3.65* 19 3.62 ± 1.76 Example 7 23 15.85 ± 8.54* 24 0.84 ± 1.12 Example 8 21  13.57 ± 1.69** 21 0.17 ± 2.03 Example 9 27  16.45 ± 5.23** 22 −1.45 ± 0.74   Comparison with control groups, *P < 0.05, **P < 0.01. EXAMPLE 10 The Bread Containing Lutein, Zeaxanthin, Zinc, Selenium [0058] Besides conventional plain and strong flour, sugar, butter for stirring, yeast, certain amount of bread improver, the formula bread contained components beneficial for eye health like lutein, zeaxanthin, zinc, selenium. Based on the total amount of 1000 g, 80.0 mg lutein, 19.4 mg zeaxanthin, 60 mg zinc, 150□μg selenium and a proper amount of sodium D-ascorbate are contained thereinto. The used lutein was in the form of 10% CWS dry powder, and zeaxanthin was in the form of 12% CWS dry powder. The zinc was zinc sulfite; selenium was selenium-enriched Brewer's yeast. The obtained breads have uniform fabric, golden yellow color and flavor taste. [0059] The formula milk powder was tested through human test according to the test design similar to that of Example 1, and the results are shown in Table 4. EXAMPLE 11 The Soft Gelatin Capsule Rich in Lutein, Zeaxanthin, Zinc, Selenium [0060] Based on the weight of 250 mg per soft capsule, the following components are included: 40 mg aliphatic ester of lutein, 5 mg zeaxanthin (20 mg/kg), 10 mg vitamin E, 15 mg vitamin C, 3.6 mg zinc orotate, 24 μg sodium selenite, 18 mg phosphatidylcholine, 20 mg soybean oil, wherein the used aliphatic ester of lutein has the concentrate 75% OS and the zeaxanthin was in the form of 20% OS. [0061] The soft gelatin capsule was tested through human test according to the test design similar to that of Example 1, and the results are shown in Table 4. EXAMPLE 12 The Soft Gelatin Capsule Rich in Lutein, Zeaxanthin, Zinc, Selenium [0062] Based on the weight of 250 mg per soft capsule, the following components are included: 20 mg lutein (80 mg/kg), 20 mg zeaxanthin (80 mg/kg), 8 mg vitamin E, 10 mg vitamin C, 1.8 mg zinc orotate, 32 μg sodium selenite, 14 mg phosphatidylcholine, 26 mg soybean oil, wherein the used zeaxanthin was in the form of 25% OS. [0063] The soft gelatin capsule was tested through human test according to the test design similar to that of Example 1, and the results are shown in Table 4. EXAMPLE 13 Tablet Rich in Lutein, Zeaxanthin, Zinc, Selenium [0064] Based on the weight of 250 mg per Tablet, the following components are included: 40 mg aliphatic ester of lutein, 5 mg zeaxanthin (20 mg/kg), 10 mg vitamin E, 15 mg vitamin C, 3.6 mg zinc orotate, 24 μg sodium selenite, 18 mg phosphatidylcholine, 20 mg soybean oil, wherein the used aliphatic ester of lutein has the concentrate 75% OS and the zeaxanthin was in the form of 20% OS. [0065] The soft gelatin capsule was tested through human test according to the test design similar to that of Example 1, and the results are shown in Table 4. [0000] TABLE 4 The Changing Rate Of Visuognosis Persistence After Feeding Among Different Groups Test groups Control groups No. of Average changing No. of Average changing Examples subjects rate (%) subjects rate (%) Example 10 19 12.53 ± 3.55*  19 3.52 ± 1.76 Example 11 21 13.87 ± 1.59** 21 0.27 ± 2.03 Example 12 27 16.85 ± 5.33** 22 −1.55 ± 0.64   Example 13 21 13.77 ± 1.69** 21 0.27 ± 2.03 Comparison with control groups, *P < 0.05, **P < 0.01. [0066] Although the present invention has been described in connection with the above embodiments, it should be understood that the present invention is not limited to such embodiments and procedures set forth above. The embodiments and procedures were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention. It will be apparent to those skilled in the art that various substitution, modifications and changes may be thereto without departing from the scope and spirit of the invention. Therefore, the intention is intended to cover all alternative constructions and equivalents falling within the spirit and scope of the invention as defined only by the appended claims and equivalents thereto. [0067] The foregoing detailed description is given primarily for clearness of understanding and no unnecessary limitations are to be understood therefrom, for modification will become obvious to those skilled in the art upon reading this disclosure and may be made upon departing from the spirit of the invention and scope of the appended claims. Accordingly, this invention is not intended to be limited by the specific exemplifications presented hereinabove. Rather, what is intended to be covered is within the spirit and scope of the appended claims. [0068] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements. [0069] Having thus described the invention, it is now claimed:

The present invention provides a formula food comprising lutien, zeaxanthin, zinc, and selenium beneficial for eye health and its application. The formula food is not only applied for dietary supplement tablets and capsules, but also applied for various formula milk powders, various functional beverages, various baked food. The formula food is conducive to the human eye health, especially beneficial for the improvement of visuognosis persistence of human eyes, helpful for asthenopia remission and the improvement of eye consciousness symptoms.

BACKGROUND OF THE INVENTION The invention relates to a method for implementing switching in the time domain, and to a method for implementing switching in the space domain, for signals of several different levels of hierarchy, the signals having a common frame structure. An example of such a frame structure is the frame structure of an STM-1 signal used in the SDH system; this frame structure will be illustrated in greater detail below. The method of the invention can thus be used in both time and space switches. In this connection, the term time switch refers to a device capable of switching the contents of any time slot in the frame structure of an incoming signal to any time slot in an outgoing frame structure (switching in time). In addition to a time switch, this device can also be called a time slot interchanger. The term space switch, in turn, refers to a switch capable of connecting any incoming line to any outgoing line (switching in space). In known switching methods, the switching of e.g. the tributary unit groups (TU-12, TU-2, TU-3) of an STM-1 frame is implemented by giving switching instructions separately to 3, 21 or 63 columns by starting the switching from column 13 on TU-3 level and from column 19 on TU-2 and TU-12 levels. It has thus been possible to effect the switching on one level at a time. Another way has been to switch columns 19 to 270 in blocks of 63 columns, and to give switching instructions separately to columns 13 to 18 on the TU-3 level. In this way it has been possible to effect cross-connection on all three of the levels at the same time. The drawback of the known switching methods is, however, that, in practice they entail fairly complicated equipment. SUMMARY OF THE INVENTION The object of the present invention is to remedy the drawback described above. The idea of the invention is to utilize the frame structure of an incoming signal by defining a basic switching block, which recurs in the frame structure in the same form from the point of view of switching, and to effect the switching of all time slots merely on the basis of an address control memory intended for the switching of the basic switching block by reading the said memory cyclically, and by skipping the switching instructions at the time slots which are not cross-connected. Owing to the solution of the invention, it is not necessary to inform the actual switch about the level of the signals to be cross-connected. The solution thus allows the practical equipment to be implemented in a more simplified manner than before. BRIEF DESCRIPTION OF THE DRAWINGS In the following, the invention will be described in more detail with reference to the examples which are based on an STM-1 signal and illustrated in the attached drawings, in which FIG. 1 shows the basic structure of a single STM-N frame, FIG. 2 shows the structure of a single STM-1 frame, FIG. 3 shows the assembly of the STM-N frame from existing PCM systems, FIG. 4 shows an STM-1 frame and blocks of different sizes contained in it, FIG. 5 shows a time switch and implementation of time switching according to the invention, FIG. 6 is a more detailed view of the read unit of the time switch shown in FIG. 5, FIG. 7A and 7B show how the switching instructions of the address control memory in the time switch of the invention are distributed to the different channels in three separate cases, FIG. 8 shows how the switching instructions of the address control memory in the time switch of the invention are distributed to the channels of different levels of hierarchy in a case where signals of three different levels of hierarchy are switched simultaneously, and FIG. 9 shows a solution of the invention as applied to a space switch. DETAILED DESCRIPTION FIG. 1 illustrates the structure of an STM-N frame used in the SDH network, and FIG. 2 illustrates a single STM-1 frame. The STM-N frame comprises a matrix with 9 rows and N×270 columns so that there is one byte at the junction point between each row and the column. Rows 1-3 and rows 5-9 of the N×9 first columns comprise a section overhead SOH, and row 4 comprises an AU pointer. The rest of the frame structure is formed of a section having the length of N×261 columns and containing the payload section of the STM-N frame. FIG. 2 illustrates a single STM-1 frame which is 270 bytes in length, as described above. The payload section comprises one or more administration units AU. In the example shown in the figure, the payload section consists of the administration unit AU-4, into which a highest-level virtual container VC-4 is inserted. (Alternatively, the STM-1 transfer frame may contain three AU-3 units, each containing a corresponding lower-level virtual container VC-3). The VC-4 in turn consists of a path overhead POH located at the beginning of each row and having the length of one byte (9 bytes altogether), fixed stuff FS located at the following two columns, TU-3 pointers or a null pointer indicator NPI located at the following three columns, fixed stuff or VC-3 path overheads (VC-3 POH) located at the following three columns, and the actual payload section PL. The null pointer indicator NPI is used to separate the tributary unit groups TUG-3 comprising TU-3 units from the tributary unit groups TUG-3 comprising TU-2 units. FIG. 3 shows how the STM-N frame can be formed of existing bit streams. These bit streams (1.5, 2, 6, 8, 34, 45 or 140 Mbit/s, shown on the right in the figure) are packed at the first stage into containers C specified by CCITT. At the second stage, overhead bytes containing control data are inserted into the containers, thus obtaining the above-described virtual container VC-11, VC-12, VC-2, VC-3 or VC-4 (the first suffix in the abbreviations represents the level of hierarchy and the second suffix represents the bit rate). This virtual container remains intact while it passes through the synchronous network up to its point of delivery. Depending on the level of hierarchy, the virtual containers are further formed either into so-called tributary units TU or into AU units (AU-3 and AU-4) already mentioned above by providing them with pointers. The AU unit can be mapped directly into the STM-1 frame, whereas the TU units have to be assembled through tributary unit groups TUG and VC-3 and VC-4 units to form AU units which then can be mapped into the STM-1 frame. In FIG. 3, the mapping is indicated by a continuous thin line, the aligning with a broken line, and the multiplexing with a continuous thicker line. As is to be seen from FIG. 3, the STM-1 frame may be assembled in a number of alternative ways, and the contents of the highest-level virtual container VC-4, for instance, may vary, depending on the level from which the assembly has been started and in which way the assembly has been performed. The STM-1 signal may thus contain, e.g., 3 TU-3 units or 21 TU-2 units or 63 TU-12 units (or an arbitrary combination of some of the above-mentioned units). As the higher-level unit contains several lower-level units, e.g. the VC-4 unit contains TU-12 units (there are 63 such units in a single VC-4 unit, cf. FIG. 3), the lower-level units are mapped into the higher-level frame by interleaving so that the first bytes are first taken consecutively from each one of the lower-level units, then the second bytes, etc. Accordingly, when the VC-4 signal contains, e.g., the above-mentioned 63 TU-12 signals, these signals are located in the VC-4 frame as shown in FIG. 2, i.e. the first byte of the first TU-12 signal is located first, then the first byte of the second TU-12 signal, etc. After the first byte of the last signal, i.e. the 63rd TU-12 signal, the second byte of the first TU-12 signal follows, etc. The following table shows the contents of the columns of the STM-1 frame as a summary, depending on whether the frame contains TU-12, TU-2 or TU-3 units. ______________________________________Col-umnNum-ber TU-12 TU-2 TU-3______________________________________1-9 SOH SOH SOH10 VC-4 POH VC-4 POH VC-4 POH11-12 fixed stuff fixed stuff fixed stuff13-15 NPI NPI TU-3 pointers16-18 fixed stuff fixed stuff VC-3 POH19-81 1 × 63 × TU-12 3 × 21 × TU-2 21 × 3 × TU-382- 1 × 63 × TU-12 3 × 21 × TU-2 21 × 3 × TU-3144145- 1 × 63 × TU-12 3 × 21 × TU-2 21 × 3 × TU-3207208- 1 × 63 × TU-12 3 × 21 × TU-2 21 × 3 × TU-3270______________________________________ The SDH system is described more closely, e.g., in References [1] to [3] (these references being listed at the end of the specification). On the basis of the above, the frame of the STM-1 signal can be illustrated with respect to the switching as shown in FIG. 4. It consists of blocks of two types: e.g. the first 18 bytes, consisting of section and path overheads, on each row form the first block 41, and the following 63 bytes on each row form the second block 42, of which there are four successive ones in a single STM-1 frame 4. The data contained in the first block are not cross-connected (except for columns 13 to 18 in the case of TU-3 signals), but it continues in the same time slots even in the outgoing frame. FIGS. 5 and 6 show the solution of the invention in connection with time switching. FIG. 5 is a block diagram illustrating the structure of the time switch, and FIG. 6 is a more detailed view of the read unit 63 shown in FIG. 5. The time switch shown in this example is the object of copending Finnish Patent Applications No. 923295 and 923296, filed Jul. 17, 1992. However, the method of the invention can also be used in conventional time switches. The time switch (FIG. 5) comprises only one memory block 61, which is twice as large as the largest frame block. In this case the size of the memory block 61 is thus 126 bytes. Writing into the memory is controlled by a simple counter 62, which is not in synchronization with the incoming signal frame (but is in synchronization with the clock signal), and which counts continuously from 1 to 126. The bytes of an incoming signal containing frame blocks of different sizes are written continuously into the memory at the address WA given by the counter, this address being incremented by one for each byte. The writing is effected without synchronization with the incoming signal frame, i.e. starting from an arbitrary location in the frame. The write address WA given by the counter 62 is also supplied to a read unit 63, more specifically to a subtractor circuit 64 therein (FIG. 6), which generates the delay by subtracting the value 63 from the write address (in this case the cross-connection delay has the length of 63 bytes, and in general, it is as long as the duration of the largest frame block in bytes). The read address thus obtained is supplied to an adder circuit 65, which adds the read address to the switching data obtained from the address control memory 66. The above-described basic structure of the STM-1. frame allows TU-2/3 signals to be switched as if they were made of TU-12 signals. This can be done by defining 63 consecutive bytes of the STM-1 frame as a basic switching block. Since all of these blocks (columns 19-81, 82-144, 145-207 and 208-270 in the STM-1 frame) are switched in the same manner, it is not necessary to define more than one switching matrix for them. The address control memory thus has the length of 63 memory locations, it is read cyclically in the manner described above, and it gives cross-connection data to each time slot of said blocks so that each TU-12 channel has its own switching instruction, or each TU-2 channel has three similar switching instructions, or each TU-3 channel has 21 similar switching instructions. In this example, a relative read address is used as the switching data in the address control memory. This means that the switching data at each memory location in the address control memory indicates the relative transition of the data contained in the time slot within the frame structure. The relative address is positive if the signal leaves the time switch in a relatively earlier time slot than it came in, and negative in the opposite case. A relative address can have (integer) values between -62 and +62, but not, however, in every time slot; each time slot has its own acceptable range within which the relative read address can be. The first time slot of each row of each frame block 42 can thus have only positive address values (from 0 to +62), the second time slot can have address values from -1 to +61, etc., and the last time slot can have only negative values and zero, i.e. address values from 0 to -62 (all of the above-mentioned lowest and highest values included). The use of the relative read address is described more closely in the above-mentioned Finnish Patent Applications which are referred to for a more detailed description. As the multiplexing of tributary unit groups of different levels of hierarchy is based on byte interleaving, columns 19, 22, 25 . . . 268 form the first TU-3 unit, columns 20, 23, 26 . . . 269 form the second TU-3 unit, and columns 21, 24, 27 . . . 270 form the third TU-3 unit, or correspondingly the first, second and third TUG-3 unit, which contains TU-2 and/or TU-12 units (cf. FIG. 3). So, for example, switching instruction words (memory locations) 1, 4, 7, 10, 13 . . . 61 give the switching instruction to the first TU-3 channel, instruction words 2, 5, 8, 11, 14 . . . 62 give it to the second TU-3 channel, and instruction words 3, 6, 9, 12, 15 . . . 63 give it to the third TU-3 channel. FIG. 7 illustrates how the switching instruction words (memory locations) of the address control memory are connected with the different channels in cases where the STM-1 frame contains (i) only TU-12 units, (ii) only TU-2 units, and (iii) only TU-3 units. The address control memory receives information on the phase of the frame from an output 67a of a phase identification circuit 67. A column flag CFLG, which provides information on when columns 1 to 12 are in progress in the frame, is obtained from another output 67b of the phase identification circuit 67. When this flag is valid (during these columns), the output of the address control memory is forced to become zero, i.e. during these columns the adder circuit 65 is not given cross-connection data. On account of the relative address being zero, the data in the columns passes "straight" through the switch (i.e. leaves the switch in the same time slot as it came in). The output of the adder circuit 65 thus has the valve (WA-63), whereas each time slot of the blocks 42 has the value (WA-63+relative read address), in which the relative read address is within a certain range depending on the time slot, as stated above. In addition, the contents of the address control memory must be interpreted at columns 13 to 18 (cf. the above table); i.e. it must be verified whether the switching instruction is reasonable. If other columns than columns 13 to 15 are addressed during these columns, the instruction is not reasonable, and a column relating to any TU-3 signal cannot be concerned. The same applies to columns 16 to 18 as well. If the switching instruction is not reasonable, the null pointer indicator NPI is generated into columns 13 to 15, and correspondingly fixed stuff into columns 16 to 18. If the instruction is a reasonable TU-3 level switching instruction, it may be part of a TU-3 or TU-2 switching instruction, or it may be a TU-12 switching instruction. The column in question can be switched in any case, for if a TU-2 or TU-12 signal is switched by a TU-3-type instruction, it is switched from an incoming TUG-3 unit, which in this case cannot contain a TU-3 signal. Therefore it does not matter if the location of the null pointer indicator should change. FIG. 8 shows an example of the contents of the address control memory when the basic switching block comprises a combination of signals of different levels of hierarchy (which may be of any kind, depending on how a single STM-1 frame can be assembled, cf. FIG. 3). In this case, the same instruction has been copied into each TU-3 channel at intervals of three memory locations, into each TU-2 channel at intervals of 21 memory locations, and each TU-12 channels has only one switching instruction. The solution of the invention can also be used an a space switch 90 shown in FIG. 9. In the example, the space switch has four inputs and four outputs. It is provided with four multiplexer units 91, each of which comprises a 4/1 multiplexer 92 and an address control memory 93. The inputs of each multiplexer 92 are connected to the corresponding input of the space switch (shown in the figure merely with respect to the first multiplexer), and the output of each multiplexer forms one of the outputs of the space switch. Each 4/1 multiplexer is controlled by a separate address control memory 93. In this case, a single address control memory has 63 memory locations, and the switching data are grouped according to FIGS. 7A, 7B and 8. In this case, the most preferable form of a switching instruction is, however, not the relative read address but the absolute address, i.e. the number of the incoming STM-1 signal (the number of the input line), which in this case is from 1 to 4. This number indicates the STM-1 signal the byte of which is switched at that particular moment to the output of the multiplexer. When the STM-1 frame begins, the reading of the switching instruction words is started one time slot at a time. This is continued until the instruction word 18, whereafter the process returns to the beginning, and all the 63 instruction words are read. This is effected four times, whereafter a new STM-1 frame begins. During columns 1 to 12 the switching data is always skipped, i.e. cross-connection is not performed but the data is switched straight through (the bytes of the first input are switched to the first output, the bytes of the second input to the second output, etc.). Information on the phase of the frame is received from a phase identification circuit 94. In the space switch, columns 13 to 18 need not be interpreted as in the case of the time switch, since in the space switch erroneous switching cannot be performed in the same way as in the time switch. As the space switch is known per se, it will not be described here in greater detail. Even though the invention has been described above with reference to the examples shown in the attached drawings, it is obvious that the invention is not restricted to them but may be modified in various ways within the inventive idea disclosed above and in the accompanying claims. Even though the invention has been described with reference to an SDH specific STM-1 signal, the solution of the invention can also be used in connection with any time division multiplex signal. References: [1] CCITT Blue Book, Recommendation G.709: "Synchronous Multiplexing Structure", May 1990. [2] SDH--Ny digital hierarki, TELE 2/90. [3] CCITT Blue Book, Recommendation G.783: "Characteristics of Synchronous Digital Hierarchy (SDH) Multiplexing Equipment Functional Blocks," August 1990, Annex B.

A method for implementing switching in the time or space domain, in which the switching is effected on the basis of switching data contained in an address control memory, and a basic switching block is defined on the basis of an incoming frame structure so that the number of its time slots corresponds to the greatest possible number of signals of the lowest level of hierarchy to be switched in the frame. The basic switching block recurs in the same form with respect to switching. In order for the switching to be simplified: (i) the number of the switching instructions to be stored in the address control memory corresponds to the size of the basic switching block, whereby when the basic switching block also contains higher-level signals, the same switching instruction is used in the address control memory at given intervals, depending on how the signals occur in the basic switching block, (ii) the same address control memory is read during the entire frame structure, whereby it gives a switching instruction to all time slots in the frame, and (iii) the switching instructions read from the address control memory are skipped during the time slots which are not cross-connected.

CROSS REFERENCE TO RELATED APPLICATION [0001] This application is a continuation of pending U.S. application Ser. No. 12/944,017, filed on Nov. 11, 2010, the entirety of which is herein incorporated by reference, which is a divisional of U.S. application Ser. No. 11/032,285, filed on Jan. 10, 2005, now U.S. Pat. No. 7,854,022, issued Dec. 21, 2010. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to garments. More particularly, the present invention relates to garments having edge bands seamlessly secured thereto and processes for making such garments. [0004] 2. Description of Related Art [0005] Many types of garments require bands secured to the edge of the garment. In some instances, the bands provide elasticity to the edge of the garment to maintain the garment in a desired location when worn. For example, intimate apparel garments such as, but not limited to, briefs and panties include an elastic waistband and often include elastic leg bands. Garments such as brassieres include an elastic chest band, while garments such as socks and hosiery include elastic leg bands. In other instances, the bands may provide a decorative or aesthetic effect to the garment. [0006] Sewn seams have traditionally been used to secure bands to the garment edges; however, in applications where a band rests against the skin of the wearer, the sewn seams may be a source of physical and/or aesthetic discomfort. For example, the seams may cause chaffing and discomfort to the skin, and may be bulky so as to be seen through the outer clothing of the wearer. [0007] Adhesives have been previously used to secure bands to garments. While adhered bands can resolve some of the discomforts associated with sewn seams, the adhered bands can lead to other deleterious effects. For example, the normal washing and drying cycles that typical garments are exposed to require the use of aggressive adhesives that may diminish the elasticity of the band and/or negatively effect the hand feel of the garment. Also, the manufacture of garments having adhered bands has proven to require additional process steps that lead to increased garment costs and decreased productivity. [0008] The use of sonic energy, both subsonic and ultrasonic, to bond or weld (hereinafter “weld”) materials having thermoplastic components has also been used to secure elastic bands to garments, such as in the disposable diaper industry. The process typically involves the use of high frequency mechanical vibrations that cause friction and melting at adjoining surfaces of the thermoplastic components, fusing them together in a strong molecular bond. Typically, the process includes pressing the materials to be joined between a vibrating horn and an anvil. The horn channels mechanical vibrations into the materials to fuse the materials at the location of the horn. While sonically welded elastic bands can result in increased productivity, they have not proven durable enough for many non-disposable garment applications. [0009] Accordingly, there is a continuing need for garments having bands seamlessly secured thereto and processes for making such garments that resolve one or more deleterious effects and drawbacks of prior garments and processes. BRIEF SUMMARY OF THE INVENTION [0010] It is an object of the present invention to provide garments having bands seamlessly secured thereto. [0011] It is another object to provide processes for seamlessly securing bands to garments. [0012] These and other objects and advantages of the present invention are provided by a garment having a fabric layer and an edge band. The edge band and the fabric layer each include a sonically weldable material. In one embodiment, the garment comprises a sonic edge weld securing the edge band to the fabric layer along a cut edge of the garment, and an adhesive securing the edge band to the fabric layer. [0013] Further objects and advantages are provided by a process for making a garment. One process includes: (1) placing an edge band on a fabric layer, the fabric layer and edge band each including a sonically weldable material, (2) applying sonic energy to the fabric layer and the edge band so that the fabric layer and the edge band are simultaneously trimmed along a cut edge and welded to one another along the cut edge, and (3) activating an adhesive between the fabric layer and the edge band to adhere the edge band to the fabric layer. [0014] The above-described and other features and advantages of the present invention will be appreciated and understood by those skilled in the art from the following detailed description, drawings, and appended claims. BRIEF DESCRIPTION OF THE DRAWINGS [0015] FIG. 1 is a perspective view of an exemplary embodiment of a garment according to the present invention; [0016] FIG. 2 is a view of the garment of FIG. 1 prior to the addition of side seams; [0017] FIG. 3 is a sectional view taken along lines 3 - 3 of FIG. 2 ; [0018] FIG. 4 is a view of a portion of an alternate exemplary embodiment of the garment of FIG. 1 ; [0019] FIG. 5 is a sectional view taken along lines 5 - 5 of FIG. 4 ; and [0020] FIGS. 6 through 10 schematically depict an exemplary embodiment of a manufacturing process according to the present invention for the garment of FIG. 1 . DETAILED DESCRIPTION OF THE INVENTION [0021] Referring to the drawings and in particular to FIGS. 1 and 2 , an exemplary embodiment of a garment according to the present invention, generally referred to by reference numeral 10 is shown. Garment 10 includes a fabric layer 12 having an edge band 14 secured to one or more regions of the fabric layer. In the illustrated embodiment, garment 10 includes side seams 16 for securing portions of fabric layer 12 to one another. [0022] Garment 10 is illustrated by way of example as a panty having an elastic edge band 14 secured to a waist region 18 and leg region 20 . Of course, it is contemplated by the present invention for garment 10 to be any other apparel or clothing item such as, but not limited to, a brassiere, a shirt, a pair of pants, a coat, a sock, a pair of pantyhose, a bathing suit, a camisole, a boxer short, a men's brief, and any other clothing item having an edge band secured to any desired region. [0023] In addition, garment 10 is illustrated by way of example having a single fabric layer 12 . Of course, it is contemplated by the present invention for the garment to include more than one fabric layer 12 . [0024] Edge band 14 is seamlessly secured to fabric layer 12 by an edge weld 22 and an adhesive 24 . As described in detail below, the energy input into garment 10 to define edge weld 22 may also simultaneously trim fabric layer 12 and edge band 14 to define a cut edge 26 of garment 10 . Advantageously, edge weld 22 also seals cut edge 26 so that the free outer edge of fabric layer 12 and a free edge of the edge band 14 terminate at the same point and do not fray during use of garment 10 . Further, the simultaneous cutting of fabric layer 12 and edge band 14 at cut edge 26 ensures that the fabric layer and band are co-planar at the cut edge. Thus, fabric layer 12 and edge band 14 are sonically welded to one another along cut edge 26 and are adhered to one another in the remaining portions where the band overlaps the fabric layer. In one embodiment, the adhesive 24 is applied along more than half of the inner surface of the edge band 14 . [0025] In some embodiments, edge band 14 may further be seamlessly secured to fabric layer 12 by one or more tack welds 28 . As described in detail below, edge weld 22 , and tack welds 28 if present, hold fabric layer 12 and edge band 14 in place with respect to one another during the manufacturing process prior to activation of adhesive 24 . [0026] Fabric layer 12 and/or edge band 14 may be formed of any non-woven fabric, woven fabric, or knitted fabric having between about ten percent and about one hundred percent of a sonically weldable material and all subranges therebetween. Sonically weldable materials include polypropylene, lycra spandex, tricot, polyester, nylon, acrylic, vinyl, PVC, thermoplastic urethane, or any combinations and blends thereof. Advantageously, fabric layer 12 and/or edge band 14 have up to about ninety percent natural fibers. [0027] In one embodiment, fabric layer 12 and/or edge band 14 may be a blend of about sixty percent sonically weldable material and about forty-percent natural fibers. In another embodiment, fabric layer 12 is a blend of about twelve percent sonically weldable material and about eighty-eight percent natural fibers, while edge band 14 is a one hundred percent sonically weldable material. It is believed that fabric layer 12 and/or edge band 14 may include at least about 70 percent natural fibers. [0028] The adhesive 24 may be any heat activated adhesive material. In some embodiments, adhesive 24 may impart a desired elasticity to garment 10 . In other embodiments, edge band 14 alone, or in combination with adhesive 24 , may impart a desired elasticity to garment 10 . Thus, garment 10 may be provided with elasticity at its edges by adhesive 24 , edge band 14 , or any combination thereof. [0029] Adhesive 24 is preferably a heat activated adhesive net or film. For example, adhesive 24 may be a heat activated adhesive net that provides elasticity to garment 10 such as the adhesive nets commercially available under the DELNET® tradename from Delstar Technologies of Austin, Tex. In another example, adhesive 24 may be a heat activated elastic film such as the adhesive films commercially available under the tradename SEWFREE® from Bemis Associates Incorporated of Shirley, Mass. [0030] Referring now to FIGS. 4 and 5 , an alternate exemplary embodiment of garment 10 is shown. Here, fabric layer 12 and edge band 14 are shown having various decorative features incorporated therein. For example, cut edge 26 is provided with a decorative pattern 30 such as, but not limited to, a scallop edge. Again, edge weld 22 is defined at decorative pattern 30 to seal cut edge 26 . [0031] In addition, fabric layer 12 and edge band 14 may include multiple cut edges 26 to provide garment 10 with a decorative effect 32 , such as a lace effect. Here, an edge weld 22 is defined at each of the cut edges 26 of decorative effect 32 . [0032] In some embodiments, edge band 14 may further be seamlessly secured to fabric layer 12 by one or more tack welds 28 . However, it has also been found that provision of multiple cut edges 26 and, thus, multiple edge welds 22 , not only provides decorative effect 32 , but also can mitigate the need for additional tack welds 28 . [0033] An exemplary embodiment of a process 40 for making garment 10 is described with reference to FIGS. 6 though 10 . During a first step of process 40 shown in FIG. 6 , fabric layer 12 is trimmed to the approximate shape of the finished garment. For example, fabric layer 12 may be trimmed to define a selvage 42 outside a final garment shape 44 (illustrated in phantom). [0034] During a second step of process 40 , shown in FIG. 7 , edge band 14 is secured to fabric layer 12 along a portion of waist region 18 . During the second process step, adhesive 24 and edge band 14 are placed on fabric layer 12 to cover a portion of selvage 42 and a portion of final garment shape 44 . [0035] In a preferred embodiment, adhesive 24 is laminated on edge band 14 prior to placement of the edge band on fabric layer 12 . Here, edge band 14 is placed on fabric layer 12 so that adhesive 24 is in contact with the fabric layer. [0036] As edge band 14 and adhesive 24 are placed on fabric layer 12 , the edge band, adhesive, and fabric layer are sonically cut and welded along final shape 44 to define edge weld 22 (not shown) and cut edge 26 . Selvage 42 having both fabric layer 12 and edge band 14 is removed and discarded. In some embodiments, fabric layer 12 and edge band 14 are also sonically welded to define tack welds 28 (not shown). Accordingly, the second process step applies sonic energy with sufficient intensity to simultaneously cut fabric layer 12 , adhesive 24 , and edge band 14 along cut edge 26 and weld the fabric layer and edge band to one another at edge weld 22 and, if present, at tack welds 28 . For example, it is contemplated for process 40 to expose fabric layer 12 and edge band 14 to sonic energy of between about 20 and 60 kilohertz (kHz) and a pressure of between about 20 and 40 pounds per square inch (psi). [0037] In a preferred embodiment, the second process step of process 40 is carried out using a sealing and bonding machine commercially available under the tradenames SEAMMASTER or LACEMASTER from Sonobond Ultrasonics of West Chester, Pa. [0038] At this point, fabric layer 12 and edge band 14 are held in place with respect to one another by edge weld 22 and, if present, by tack welds 28 . The sonic energy that creates cut edge 26 and welds 22 , 28 also locally activates adhesive 24 . Thus, welds 22 , 28 include components of fabric layer 12 , edge band 14 , and adhesive 24 in addition to a localized area of activated adhesive surrounding around the welds. However, adhesive 24 remains un-activated in the remaining portions of overlap between fabric layer 12 and edge band 14 . [0039] During a third step of process 40 , shown in FIG. 8 , the second process step is repeated to secure edge band 14 to the remaining waist and leg regions 18 , 20 , as desired. Again, fabric layer 12 and edge band 14 are held in place with respect to one another by the sonic welds, but adhesive 24 remains largely un-activated. [0040] Process 40 can be easily modified to provide tack welds 28 , decorative pattern 30 , and/or decorative effect 32 as desired. For example, the horn used to apply sonic energy during the second and third steps may be modified using known methods to provide the tack welds 28 , decorative pattern 30 and/or decorative effect 32 , as desired. [0041] During a fourth step of process 40 , shown in FIG. 9 , adhesive 24 is activated. For example, fabric layer 12 and edge band 14 may be compressed between a pair of presses 46 at a pressure, temperature, and/or time sufficient to activate adhesive 24 . At the end of the fourth step, fabric layer 12 and edge band 14 are secured to one another by edge weld 22 , adhesive 24 , and tack welds 28 , if any. [0042] Finally, garment 10 may be completed by folding the garment and adding side seams 16 for securing portions of fabric layer 12 to one another, as shown in FIG. 10 . [0043] Advantageously, process 40 uses sonic welds 22 , 28 to hold fabric layer 12 and edge band 14 in place with respect to one another while cutting through both the edge band and fabric, so that the edges are co-planar with one another. Process 40 then activates adhesive 24 to firmly secure edge band 14 to fabric layer 12 without deleteriously effecting the elastic characteristics of the edge band or the hand feel of the edge band and fabric. It has been determined that the combination of edge weld 22 and adhesive 24 , as well as tack welds 28 if present, provide garment 10 with a desired durability, washability, hand feel, and method of manufacture not previously possible. [0044] It should also be noted that the terms “first”, “second”, “third”, “upper”, “lower”, and the like may be used herein to modify various elements. These modifiers do not imply a spatial, sequential, or hierarchical order to the modified elements unless specifically stated. [0045] While the present disclosure has been described with reference to one or more exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the present disclosure. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the scope thereof. Therefore, it is intended that the present disclosure not be limited to the particular embodiment(s) disclosed, but that the disclosure will include all embodiments falling within the scope of the appended claims.

A method is provided for forming a garment, including providing a fabric layer having sonically weldable material, the fabric layer having an inner surface and at least one opening region, the opening region having a periphery and an outer free edge, placing an elastic edge band having sonically weldable material around the entire periphery of the opening region, the edge band having first and second free edges and an inner surface, securing the first free edge of the edge band to the outer free edge of the opening region with a subsonic or ultrasonic edge weld to form a finished seamless edge along the opening region, and activating an adhesive along more than half of the inner surface of the edge band to secure the edge band and second free edge to the inner surface of the fabric layer.

FIELD OF THE INVENTION This invention relates to automatic gain control in photodetectors, such as those used in a variety of electro-optical applications. BACKGROUND AND SUMMARY OF THE INVENTION Circuits that employ an automatic gain control for controlling the gain of a photomultiplier tube (PMT) or similar photodetector are known in the prior art. For example, the prior art circuit shown in FIG. 1 employs an operational amplifier (op-amp) 10 in a integrating configuration, where resistor R and capacitor C set the integration time constant as the product R*C seconds. The filtered DC portion of the PMT output signal 12 (hereafter referred to as “PMT output”) is compared to a pre-selected DC reference 14 . The output of the op-amp 10 is applied to the bias control 16 of the PMT, thereby to drive the PMT at a level such that the PMT output matches the DC reference. For example, if the level of the PMT output reaching the op-amp 10 is below the DC reference 14 , the op-amp will provide to the PMT bias control 16 a signal for driving the PMT at a relatively higher level until the PMT output matches the DC reference. A controller (not shown) monitors and conditions the signals directed to and from the op-amp 10 . For example, in instances where the DC reference is user-selected, the system provides a user interface for receiving the selected input from the user, which input the controller converts as necessary to a corresponding DC reference level applied to the op-amp 10 . It is important that, despite the selected DC reference, the PMT gain be limited to an amount that does not cause the applied bias voltage to overdrive, hence damage, the PMT. Moreover, such techniques for limiting the PMT gain should not interfere with the precision with which the PMT output may be established (by selection of the DC reference) below that limited level. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 a diagram of a prior art automatic gain control circuit for a photomultiplier tube (PMT). FIG. 2 is a diagram of a preferred embodiment of an automatic gain control for a PMT, including a mechanism for limiting the gain to a level less than that which would otherwise lead to overdriving, hence damaging, the PMT. FIG. 3 is a flow diagram for illustrating an aspect of the invention that ensures precise selection of the DC reference voltage level. DETAILED DESCRIPTION FIG. 2 is a diagram of a preferred embodiment of an automatic gain control for a PMT, including a mechanism for limiting the gain to a level less than that which would otherwise lead to overdriving, hence damaging, the PMT. The circuit of FIG. 2 includes an operational amplifier (op-amp) 20 in an integrating configuration. The filtered DC portion of the PMT output signal 22 (hereafter referred to as “PMT output”) is applied to the negative input of the op-amp 20 . The selected DC reference voltage 24 is applied to the positive input of the op-amp 20 . In this preferred configuration, however, a Zener diode 26 is interconnected between the op-amp 20 and DC reference 24 , as shown in FIG. 2 , with its anode terminal grounded. The Zener diode breakdown or Zener voltage is selected to establish the upper limit of voltage (here, the upper limit of the DC reference) that can be applied to the op-amp 20 , hence limiting the bias voltage that can be applied to the PMT via the PMT bias control 30 . In one embodiment the Zener voltage is 1.8 volts. Thus, if the DC reference 24 is selected to be above that amount, the Zener diode becomes conductive and shunts the DC reference voltage to ground, thereby preventing the undesirably high voltage from appearing at the positive input of the op-amp 20 . A resistor 28 (preferably 61.9 k Ohms in this embodiment) is located between the DC reference and the Zener diode 26 for protecting that diode from current levels that may damage the Zener diode itself. In the preferred embodiment, the Zener voltage is relatively low. One can observe that, for such a low-voltage limit, the Zener diode will become conductive at voltage levels below the limit. Put another way, the Zener diode may become “leaky” at voltage levels approaching the established Zener voltage and thus prevent the application of the correct, selected DC reference voltage from reaching the op-amp, even though the selected DC reference voltage is less than the (Zener voltage) upper limit. The consequent lack of precision in applying the particularly selected DC reference voltage to the op-amp 20 for creating the sought-after gain of the PMT is unacceptable in many applications. Accordingly, as another aspect of the present invention, there is provided a technique that compensates for the voltage drop attributable to a “leaky” Zener diode effect explained above. To this end, voltage measurements are taken at the positive input of the op-amp and correlated to the selected DC reference voltage level. Numerous such measurements are taken at suitable increments of selected DC reference levels. The correlated data is stored as a look-up table for use by the controller for compensating for losses caused by the leaky Zener diode. This is explained in more detail next, with reference to the flow diagram of FIG. 3 . An implementation of the present invention may provide a user interface 32 whereby the user may select the desired PMT gain represented by the DC reference 36 . It is noteworthy here that although a user-selected DC reference signal is discussed for this embodiment, it is also contemplated that other means for establishing the desired DC reference may be used, including automated methods based, for example, on changes in environmental conditions of the photodetectors of interest. In either case, the protection of the photodetectors and compensation for leaky Zener diodes is desired. Once the user selects a DC reference value, the look-up table is consulted 34 to find the correlating voltage that is actually applied to the op-amp 20 as a result of the leaky Zener diode effect mentioned above. In instances where the actual and selected levels are unequal, the controller adjusts the DC reference 34 by the difference indicated in the look-up table so that the level applied to the op-amp 20 will match what the user selected for the desired gain of the PMT. As noted, it is contemplated that the present invention is useful for automatic gain control of other types of photodetectors, such as avalanche photo-diodes. Also, other mechanisms for limiting the voltage applied to the op-amp may be used. For example, a resistor could be used in lieu of the Zener diode, with a corresponding look-up table developed and stored for use as discussed above.

The amount of gain applied to a photodetector such as a photomultiplier tube (PMT) is limited to an amount that does not cause the applied PMT bias voltage to overdrive, hence damage, the PMT. Techniques for limiting the PMT gain are implemented in a way that does not interfere with the precision with which the PMT gain may be established (by selection of a reference level) below that limited level.

CROSS-REFERENCE TO RELATED APPLICATIONS This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2002-106918, filed Apr. 9, 2002, the entire contents of which are incorporated herein by reference. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display control device and a method of preparing patterns for the same device. 2. Description of the Related Art A frame modulation gradation display method has been known as the gradation display method of a matrix type liquid crystal display panel (LCD panel). According to the above frame modulation method, gradation display is possible on the LCD panel even if a single pixel only makes binary display (on display and off display). According to the frame modulation method, on display and off display are properly combined in the time axis direction, and thereby, pseudo gradation display is possible. For example, if a 16-gradation level image is displayed, 16 frames are set as one cycle, and on frame and off frame are determined in accordance with gradation level. As a result, a desired gradation is obtained as the mean value of 16 frames. As described above, according to the frame modulation method, several frames are set as one cycle. For this reason, the number of gradation levels increases, and thereby, flicker conspicuously appears; as a result, display quality worsens. Thus, if the 16-gradation level image is displayed, a display pattern is formed using 4 horizontal direction pixels and 4 vertical direction pixels, that is, the total 4×4=16 pixels. By doing so, the display quality can be prevented from deteriorating. The following is a description on memory capacity required for storing the above display pattern. For example, if the 16-gradation level image is displayed, the following memory capacity is required. The memory capacity is 4096 bits=16 (the number of pixels in a display pattern)×16 (the number of frames)×16 (the number of gradation levels). If a microcomputer having built-in memory performs display control, preferably, the number of bits for storing the display pattern is reduced as much as possible because the number of bits of the built-in memory is limited. In the frame modulation method, the display pattern for each gradation level is not necessarily optimized. For this reason, there is a problem that display quality worsens. As described above, conventionally, there are problems that the memory capacity for storing the display pattern becomes much, and the display pattern is not optimized. BRIEF SUMMARY OF THE INVENTION According to a first aspect of the present invention, there is provided a liquid crystal display control device for making gradation display on a liquid crystal display panel using binary display patterns, comprising: a memory section storing a plurality of pattern data items for a plurality of gradation levels, each of the pattern data items defining a plurality of binary display patterns set for a plurality of basic frames, and each of the binary display patterns being defined by a plurality of basic pixels; and a selector section selecting one of the pattern data items, which corresponds to a designated gradation level; wherein the number of the basic frames and the number of the basic pixels for each of the gradation levels are predetermined and depend on each of the gradation levels. According to a second aspect of the present invention, there is provided a method of preparing binary display patterns used for making gradation display on a liquid crystal display panel, a plurality of the binary display patterns being set for a plurality of basic frames, and each of the binary display patterns being defined by a plurality of basic pixels, comprising: determining a darkest basic pixel in a basic frame; lighting the darkest basic pixel; obtaining a binary display pattern for the basic frame by repeating the determining a darkest basic pixel and the lighting the darkest basic pixel; determining whether binary display patterns for all basic frames satisfy a predetermined condition; performing, in a next basic frame, the determining a darkest basic pixel to the determining whether binary display patterns for all basic frames satisfy a predetermined condition, when it is not determined that the binary display patterns for all basic frames satisfy the predetermined condition; and determining the binary display patterns satisfying the predetermined condition as final binary display patterns, when it is determined that the binary display patterns for all basic frames satisfy the predetermined condition. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING FIG. 1 is a block diagram showing the configuration of a liquid crystal display control device according to an embodiment of the present invention; FIG. 2A to FIG. 2D are views each showing a basic pixel group according to an embodiment of the present invention; FIG. 3A to FIG. 3D are views each showing an arrangement of the basic pixel group according to an embodiment of the present invention; FIG. 4 is a view showing display patterns according to an embodiment of the present invention; FIG. 5 is a view to explain the detailed configuration and operation of the liquid crystal display control device according to an embodiment of the present invention; FIG. 6 is a view showing an arrangement of the basic pixel group according to an embodiment of the present invention; FIG. 7 is a view showing a brightness change of pixel according to an embodiment of the present invention; and FIG. 8 is a flowchart showing a method of obtaining the optimal display pattern according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. (First Embodiment) The following is a description on the case where a 16-gradation image is displayed on a matrix type liquid crystal display panel in which only binary display is made in a single pixel. If the 16-gradation image is displayed, there exist the total 17 gradation levels from the case where all pixels are off state (0 gradation level) to the case where all pixels are on state (16-th gradation level). In the embodiment, the 15-th gradation level (the case where 15 pixels are on state) is not used so that the total number of gradation levels becomes 16. FIG. 1 is a block diagram showing the configuration of a liquid crystal display control device according to the first embodiment. The liquid crystal display control device includes a control section 11 , a memory section (look-up table) 12 , and a selector section 13 . The memory section 12 stores binary display patterns (hereinafter, referred simply to display patterns) of each gradation level. The selector section 13 selects pattern data (set of display patterns) corresponding to the designated gradation level. The above constituent elements are built in a single IC chip. In the first embodiment, the number of pixels (basic pixels) forming the display pattern is predetermined depending on gradation level. In addition, the number of display patterns (the number of basic frames) is predetermined depending on gradation level. For example, if the number of basic pixels is 4, one cycle includes 4 basic frames, and the number of basic frames is 4. More specifically, as shown in FIG. 2A to FIG. 2D , in the first, third, fifth, seventh, ninth, 11th and 13th gradation levels (hereinafter, referred to as first type) (see FIG. 2A ), the basic pixel group is composed of 4×4=16 pixels, and the number of basic frames is 16. In the second, sixth, tenth and 14th gradation levels (hereinafter, referred to as second type)(see FIG. 2B ), the basic pixel group is composed of 4×2=8 pixels, and the number of basic frames is 8. In the fourth and 12th gradation levels (hereinafter, referred to as third type) (see FIG. 2C ), the basic pixel group is composed of 2×2=4 pixels, and the number of basic frames is 4. In the eighth gradation level (hereinafter, referred to as fourth type) (see FIG. 2D ), the basic pixel group is composed of 2×1=2 pixels, and the number of basic frames is 2. In FIG. 2A to FIG. 2D , (i, j) shown in each pixel is each pixel position of X and Y directions in the basic pixel group. FIG. 3A to FIG. 3D show the arrangement of each basic pixel group of the above first to fourth types. FIG. 3A to FIG. 3D show the first to fourth types, respectively. FIG. 4 shows display patterns of basic frames set for the seventh gradation level. As seen from FIG. 4 , in each basic frame, seven pixels are on state. Any pixels included in the basic pixel group are on state in seven of 16 frames. Here, the total memory capacity when the above method is employed is as follows. In the first type, the memory capacity is 1792 bits=16 (the number of pixels in a display pattern)×16 (the number of frames)×7 (the number of gradation levels). In the second type, the memory capacity is 256 bits=8 (the number of pixels in a display pattern)×8 (the number of frames)×4 (the number of gradation levels). In the third type, the memory capacity is 32 bits=4 (the number of pixels in a display pattern)×4 (the number of frames)×2 (the number of gradation levels). In the fourth type, the memory capacity is 4 bits=2 (the number of pixels in a display pattern)×2 (the number of frames)×1 (the number of gradation levels). Therefore, the total memory capacity is 2084 bits=1792+256+32+4. As a result, the total memory capacity is reduced to nearly half of the conventional memory capacity (4096 bits). Pattern data can be used in common for gradation level expressed by (8−c) and gradation level expressed by (8+c). That is, each display pattern of the (8−c) gradation level is obtained by inverting each display pattern of the (8+c) gradation level (on display pixel is inverted to off display pixel, off display pixel is inverted to on display pixel). As described above, the pattern data is used in common, and thereby, the memory capacity can be further reduced. More specifically, in the first type, the pattern data of seventh and ninth gradation levels is used in common, the pattern data of fifth and 11th gradation levels is used in common, and the pattern data of third and 13th gradation levels is used in common, and thereby, the memory capacity is 1024 bits. In the second type, the pattern data of sixth and tenth gradation levels is used in common, and the pattern data of second and 14th gradation levels is used in common, and thereby, the memory capacity is 128 bits. In the third type, the pattern data of fourth and 12th gradation levels is used in common, and thereby, the memory capacity is 16 bits. In the fourth type, the memory capacity is 4 bits as already described. Therefore, the total memory capacity is 1172 bits=1024+128+16+4, so that the memory capacity can be greatly reduced. FIG. 5 is a view to explain the detailed configuration and operation of the liquid crystal display control device according to the first embodiment. In FIG. 5 , 21 a to 21 d correspond to a memory section (look-up table) storing display patterns. The 21 a is a memory part storing display patterns of the first, third, fifth, seventh, ninth, 11th and 13th gradation levels (first type). The 21 b is a memory part storing display patterns of the second, sixth, tenth and 14th gradation levels (second type). The 21 c is a memory part storing display patterns of the fourth and 12th gradation levels (third type). The 21 d is a memory part storing display patterns of the eighth gradation level (fourth type). A reference numeral 22 denotes a selector section for selecting the display pattern from the above memory parts 21 a to 21 d . Reference numerals 23 a to 23 c denotes operation parts, 24 denotes a 4-bit counter. The 4-bit counter 24 inputs frame pulse, and outputs 4-bit count value k[3:0]. The operation part 23 a inputs 4-bit count value k[3:0] and data j[1:0] expressing lower 2 bits of the Y coordinate value of the current pixel. The operation result (4×k+j) in the operation part 23 a is outputted to the memory part 21 a as address data. The memory part 21 a outputs 4-bit data stored in the designated address. The operation part 23 b inputs lower 3-bit k[2:0] of the count value and lower 1 bit j[0] of the Y coordinate value. The operation result (2×k[2:0]+j[0]) in the operation part 23 b is outputted to the memory part 21 b as address data. The memory part 21 b outputs 4-bit data stored in the designated address. The operation part 23 c inputs lower 2-bit k[1:0] of the count value and lower 1-bit j[0] of the Y coordinate value. The operation result (2×k[1:0]+j[0]) in the operation part 23 c is outputted to the memory part 21 c as address data. The memory part 21 c outputs 4-bit data converted from 2-bit data stored in the designated address. The memory part 21 d inputs lower 1-bit k[0] of the count value as address data. The memory part 21 d outputs 4-bit data converted from 2-bit data stored in the designated address. According to the above operation, data of each gradation level L stored in the memory parts 21 a to 21 d is inputted to the selector section 22 . In FIG. 5 , for example, the first gradation level data of the first type is expressed as T 1 (for L=1), and the second gradation level data of the second type is expressed as T 2 (for L=2). 4-bit data expressing each gradation level of three primary colors (R gradation level L (R), G gradation level L (G), B gradation level L (B)), are inputted to the selector section 22 from the outside. In addition, lower 2-bit i[1:0] of the X coordinate value of the current pixel is inputted to the selector section 22 . Based on the above data, 1-bit output data (Rout, Gout, Bout) of each primary color is successively outputted from the selector section 22 . That is, if the gradation level belongs to the first to fourth types (i.e., first to 14th gradation levels), any one of data from the memory parts 21 a to 21 d is selected, and data selected by lower 2-bit i[1:0] of the X coordinate value is successively outputted. If the gradation level is 0-gradation level, off-display state data (logical value 0) is outputted. If the gradation level is the 16th gradation level, on-display state data (logical value 1) is outputted. As seen from the above description, according to the first embodiment, the number of basic frames and the number of basic pixels are preset in accordance with the gradation level. By doing so, it is possible to greatly reduce the memory capacity for storing display patterns. Therefore, in particular, it is effective in the case where the microcomputer having built-in memory carries out the display control of the liquid crystal display panel. The above embodiment has described the case of displaying image having the total gradation level number N of 16 (N=16). However, the total gradation level number N is not limited. For example, there exists gradation level expressed by (N/a)×b (where, a and N/a are an integer of 2 or more, b is an integer larger than 0 and smaller than a). In this case, the number of basic frames and the number of basic pixels are both set as a; therefore, the memory capacity can be effectively reduced. In addition, if the total gradation level number N is expressed by n 2 (where, n is an integer of 2 or more), the basic pixel group is composed of n×n (X-direction n pixels, Y-direction n pixels), so that deterioration of display quality can be prevented. If n 2 is an odd number, it is preferable that the total gradation level number N is N=n 2 +1. When the pattern data is used in common, c is set as an integer larger than 0 and smaller than N/2, it is preferable that common pattern data is used for gradation level expressed by c and gradation level expressed by N−c. (Second Embodiment) The following is a description on the method of obtaining the optimal display pattern in each gradation level. Matters overlapping with those described in the first embodiment are omitted. FIG. 6 shows an arrangement of the basic pixel group for the first, third, fifth, seventh, ninth, 11th and 13th gradation levels (first type). The following is a description on the brightness of the central pixel, for example, a pixel (0, 0) shown in the circle of FIG. 6 . The actual brightness of the central pixel receives the influence by the brightness of surrounding pixels, in addition to the self-brightness thereof. For instance, the self-brightness of pixel (i, j) is set as g 1 [j][i], and the actual brightness of pixel (i, j) receiving the influence by the brightness of surrounding pixels is set as g 2 [j][i]. In this case, g 2 [j][i] can be expressed by the following equation (1). g2 ⁡ [ j ] ⁡ [ i ] = g1 ⁡ [ C ⁡ ( j ) ] ⁡ [ C ⁡ ( i ) ] + ( g1 ⁡ [ C ⁡ ( j ) ] ⁡ [ C ⁡ ( i + 1 ) ] + ⁢ g1 ⁡ [ C ⁡ ( j ) ] ⁡ [ C ⁡ ( i - 1 ) ] + g1 ⁡ [ C ⁡ ( j + 1 ) ] ⁡ [ C ⁡ ( i ) ] + g1 ⁡ [ C ⁡ ( j - 1 ) ] ⁡ [ C ⁡ ( i ) ] ) / ⁢ ( Kc ⁡ ( 2 ) ) + 2.0 * ( g1 ⁡ [ C ⁡ ( j ) ] ⁡ [ C ⁡ ( i + 2 ) ] + g1 ⁡ [ C ⁡ ( j + 2 ) ] ⁡ [ C ⁡ ( i ) ] ) / ⁢ ( Kc ⁡ ( 4 ) ) + ( g1 ⁡ [ C ⁡ ( j ) ] ⁡ [ C ⁡ ( i + 3 ) ] + g1 ⁡ [ C ⁡ ( j ) ] ⁡ [ C ⁡ ( i - 3 ) ] + ⁢ g1 ⁡ [ C ⁡ ( j + 3 ) ] ⁡ [ C ⁡ ( i ) ] + g1 ⁡ [ C ⁡ ( j - 3 ) ] ⁡ [ C ⁡ ( i ) ] / ( Kc ⁡ ( 6 ) ) + ⁢ ( g1 ⁡ [ C ⁡ ( j + 1 ) ] ⁡ [ C ⁡ ( i + 1 ) ] + g1 ⁡ [ C ⁡ ( j + 1 ) ] ⁡ [ C ⁡ ( i - 1 ) ] + g1 ⁡ [ C ⁡ ( j - 1 ) ] ⁢ [ C ⁡ ( i + 1 ) ] + g1 ⁡ [ C ⁡ ( j - 1 ) ] ⁡ [ C ⁡ ( i - 1 ) ] ) / ( Kc ⁡ ( sqrt ⁡ ( 8 ) ) ) + ⁢ 4.0 * g1 ⁡ [ C ⁡ ( j + 2 ) ] ⁡ [ C ⁡ ( i + 2 ) ] / ( Kc ⁡ ( sqrt ⁡ ( 32 ) ) ) + ⁢ 2.0 * ( g1 ⁡ [ C ⁡ ( j + 1 ) ] ⁡ [ C ⁢ ( i + 2 ) ] + g1 ⁡ [ C ⁡ ( j - 1 ) ] ⁡ [ C ⁡ ( i + 2 ) ] + ⁢ g1 ⁡ [ C ⁡ ( j + 2 ) ] ⁡ [ C ⁡ ( i + 1 ) ] + g1 ⁡ [ C ⁡ ( j + 2 ) ] ⁡ [ C ⁡ ( i - 1 ) ] ) / ( Kc ⁡ ( sqrt ⁡ ( 20 ) ) ) ( 1 ) Where, Kc(r2/r1)=(r2/r1) r (1.5≦r≦2.5) In the above equation (1), r 1 is a radius when on-pixel (lighting pixel) is assumed as being a sphere, and r 2 is a distance from on-pixel. The value of r is theoretically 2. C(i) means “i mod 4”, for example, C(1)=C(5)=C(−3). The above “sqrt” means square root. The brightness of a certain frame of a certain pixel receives the influence of the frame before it. For example, as shown in FIG. 7 , when a certain pixel continuously becomes on state, the brightness of the certain pixel gradually increases. Assuming that the brightness of a certain frame of a certain pixel is set as g 1 (j,i), the brightness g 1 (j,i)next of the nest frame is expressed by the following equation (2). g 1 ( j,i )next= g 1 ( j,i )*(1 −Kr )+ Kr*Ps ( j,i )  (2) Where, 0.05≦Kr≦0.2, and in general, Kr=0.1. Ps(j,i) is 1 if pixel is on state while being 0 if pixel is off state. The method of obtaining the optimal display pattern will be described below with reference to the flowchart shown in FIG. 8 . Here, the case of obtaining the display pattern of the seventh gradation level shown in FIG. 4 will be described. In step S 1 , the initial setting is made. That is, the number of basic frames is set to 16, the number of pixels included in the basic pixel group is set to 16, and the number of on-pixels in the basic pixel group is set to 7. In addition, a pixel, which first becomes on state, is temporarily set in the basic pixel group of the first frame. In this case, the pixel is on state, that is, g 1 (0,0)=1; on the other hand, other pixels are off state, that is, g 1 (j,i)=0. In step S 2 , of the basic pixel group of the current basic frame, the darkest pixel (i.e., pixel having the lowest brightness) at that time is determined as on-pixel. Based on the above equation (1), the values of g 2 (j,i) (0≦i≦3, 0≦j≦3) of all basic pixels included in the current basic pixel group are calculated. The darkest pixel (Jmin, Imin) of the basic pixels is determined. In step S 3 , the pixel (Jmin, Imin) determined in the above step S 2 is set to on state. Then, g 1 (Jmin, Imin)next is set using the following equation based on the above equation (2). g 1 ( Jmin,Imin )next= g 1 ( Jmin,Imin )+ Kr*Ps ( Jmin,Imin ) In step S 4 , it is determined whether or not the procedures of steps S 2 and S 3 are carried out at the predetermined number of times (seven time). In other words, a decision is made whether or not all of seven on-pixels are determined in the currently selected basic pixel group. If a decision is made that all on-pixels are not determined, the process sequence returns to step S 2 , and a pixel to be on next is determined. If a decision is made that all on-pixels are determined, the operation sequence proceeds to step S 5 . In step S 5 , the pattern of the determined seven on-pixels is determined as a temporary display pattern. In step S 6 , the next basic frame is set. That is, g 1 (j,i)next values are determined with respect to all basic pixels included in the basic pixel group using the following equation based on the above equation (2). g 1 ( j,i )next= g 1 ( j,i )*(1 −Kr ) In step S 7 , it is determined whether or not the determined temporary display patterns of all basic frames (16 frames) are stable. More specifically, the finally determined display pattern is compared with the display pattern determined before it (before 16 frame) in each basic frame. If an error based on the comparative result is less than a predetermined value, the display patterns (temporary display patterns) are regarded as being stable in all of 16 frames. On the other hand, if it is determined in step S 7 that the display patterns are not stable, the operation sequence returns to step S 2 , and the operation of the next frame is carried out. In step S 7 , if it is determined that the display patterns are stable, the operation sequence proceeds to step S 8 . In step S 8 , the determined temporary display patterns of 16 frames are determined as the final display patterns. The final display patterns thus determined are stored in the memory section of the liquid crystal display control device. The above operation will be described with reference to FIG. 4 . In each of 0 to 15th frames, display pattern (that seven pixels are on state) is temporarily determined. Thereafter, the operation to the next 0 to 15th frames is carried out. That is, considering the influence of display patterns temporarily determined so far, each display pattern of the 0 to 15th frames is successively updated. The updated display pattern is successively determined as a temporary display pattern. Therefore, when the temporary display pattern is determined in each frame, display patterns (that seven pixels are on state) are obtained in all of 0 to 15th frames. In other words, every when the temporary display pattern is determined in each frame, the decision of step S 7 is made. As described above, according to the second embodiment, the optimal display pattern is determined using the principle of determining the darkest pixel (having the lowest brightness) at that time, and making (lighting) the pixel on state. When gradation display is performed in a state that on pixels and off pixels are dispersed in time and space, human's eye recognize preferable image on its characteristics when on pixels are further dispersed. The method of the second embodiment is employed, and thereby, the on pixels can be effectively dispersed in time and space, and the optimized display pattern can be obtained. In addition, in the second embodiment, the operation is repeated until the display pattern of each frame stabilizes; therefore, the display pattern can be very accurately determined. The second embodiment has described the case of determining the display pattern of the seventh gradation level when the total gradation level number N is 16. Likewise, the method of the second embodiment is applicable to other gradation levels. The total gradation level number N is not limited to 16, and the method of the second embodiment is applicable to various total gradation level numbers described in the first embodiment. Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

Disclosed is a liquid crystal display control device for making gradation display on a liquid crystal display panel using binary display patterns, comprising a memory section storing a plurality of pattern data items for a plurality of gradation levels, each of the pattern data items defining a plurality of binary display patterns set for a plurality of basic frames, and each of the binary display patterns being defined by a plurality of basic pixels, and a selector section selecting one of the pattern data items, which corresponds to a designated gradation level, wherein the number of the basic frames and the number of the basic pixels for each of the gradation levels are predetermined and depend on each of the gradation levels.

[0001] Cross-reference to related patent application, if any: None. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates generally to the field of vehicle occupant protection systems and more particularly, to those which involve the use of inflatable devices. In particular, the present invention relates to the use of an inflatable headliner system. The system is arranged to inflate upon an accident/impact to deform the headliner downwardly, away from the vehicle roof, and toward the lower portions of the vehicle interior. In the most preferred embodiment, the inflatable headliner system includes a plurality of inflatable portions which extend about its perimeter, and additional inflatable portions cross transversely in the event cross bows are included in the vehicle roof. [0004] 2. Description of the Prior Art [0005] A large number of air bag systems for occupant protection in vehicles are known. These include air bag systems mounted within the steering column, instrument panel, and other interior locations to assist occupants in the event of frontal impacts. In recent years, side air bags which may be deployed from the area around the side rail of the vehicle roof have also become popular. Air bags may also be located within the seat for deployment along the side of the vehicle when triggered by side impact sensors or the like. [0006] There is an increasing emphasis on providing impact countermeasures for all parts of an occupant's body, including the head, and countermeasures are currently employed in headliner systems, most of which involve the use of a deformable material (such as a urethane elastomer) located behind the interior or “A” surface of the headliner. Such countermeasures provide varying degrees of protection and also involve several disadvantages from the standpoint of cost, assembly time, and the like. They require so much space in some cases that the vehicle cockpit volume is substantially diminished. While no prior art is known by the present inventors which would result in the integration of an inflatable fabric within a headliner system, the inventors believe that an air cushion urging the headliner system downwardly at the time of an accident/impact would enhance overall occupant protection capabilities in a vehicle. Such an inflatable headliner system would represent a substantial advance in this art. FEATURES AND SUMMARY OF THE INVENTION [0007] A primary feature of the present invention is to provide an inflatable system integrated into the headliner of a vehicle. [0008] Another feature of the present invention is to provide an inflatable headliner system which is readily adaptable to a wide variety of vehicle roof structures. [0009] Yet another feature of the present invention is to provide an inflatable headliner system which does not significantly reduce the interior volume of the vehicle cockpit. [0010] A different feature of the present invention is to provide an inflatable headliner system which includes inflatable and, in some cases, non-inflatable portions. [0011] Yet still another feature of the present invention is to provide an inflatable headliner system which eliminates the need for complex, multi-component head impact countermeasure components. [0012] A still further feature of the present invention is to provide inflatable portions around the perimeter of an inflatable headliner system, and in a preferred form to provide air passageways between the inflatable portions. [0013] Another feature of the present invention is to provide inflatable portions which extend transversely of the vehicle where cross bows are used in the vehicle roof. [0014] Another feature of the present invention is to provide an inflatable headliner system in which openings are provided for vehicle accessories such as visors, mirrors, grab handles, coat hooks, sun roofs, and the like. [0015] How the foregoing and other features of the present invention are accomplished individually, collectively, or in various subcombinations, will be described in the following detailed description of the preferred embodiment taken in conjunction with the FIGURE. Generally, however, they are accomplished in an inflatable headliner system which includes an inflatable component integrated into the located as a sandwiched layer between other headliner layers such as structural layers, or convenience layers (e.g. sound absorption layers, cushion layers, etc.). The headliner may include various known laminate or composite layers. The inflatable component preferably includes a thin fabric sheet and a plurality of inflatable and non-noninflatable portions. The inflator(s) for the system may be located in the headers, the side rails or any of the “A”, “B”, “C” or “D” pillars. When a deployment event occurs, the headliner system is deformed urging it downwardly and away from the vehicle roof. In further preferred embodiments, inflatable portions may be separated by air flow passageways, and in vehicles which employ cross bows, additional inflatable portions may be provided beneath them. [0016] Other ways in which the features of the present invention are accomplished will become apparent to those skilled in the art after they have read this specification and are deemed to fall within the scope of the present invention if they fall within the scope of the claims which follow. BRIEF DESCRIPTION OF THE DRAWINGS [0017] [0017]FIG. 1 is an exploded view of a headliner air bag system according to a preferred embodiment of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0018] Before proceeding with the description of the preferred embodiment, several general comments can be made about the applicability and the scope thereof. [0019] First, one particular headliner system is illustrated in the FIGURE, namely one having layers of fabric, structural foam, and a reinforcement convenience layer. In addition, a few locations for attachment of vehicle interior accessories are shown, such as visors, a dome light, grab handles, a coat hook, etc. It should be understood at the outset that the present invention has broad applicability to headliner systems for cars, SUV's, vans, light trucks, and other vehicles where an inflatable headliner system can be used to enhance vehicle safety. [0020] In addition to the overall shape and dimensions of the headliner, a wide variety of other openings can be provided through the headliner for the attachment of such other accessories as infotainment devices, air ducts, computer ports, additional lighting, power outlets, sun roofs, etc. It is becoming increasingly important to motor vehicle manufacturers to provide a wide range of passenger accessible components, and overall structural and aesthetic design flexibility is enhanced when the headliner or roof area of a vehicle can be employed. [0021] The present invention is illustrated for use with a layered headliner system which includes an interior fabric layer, an intermediate structural layer, and a convenience layer which abuts the vehicle roof. A large number of different headliner constructions are known in the art, and the present invention can be used with them as well. For example, the fabric and foam layers may be readily combined into a single layer, or more layers of material can be employed, typically in higher end vehicles where a plush feel is desirable. [0022] The present specification illustrates the inflatable portion of the headliner system located between the lowermost two layers of the headliner structure, i.e., between the fabric and a structural layer. Such location is not critical, and the invention would perform its intended function if the inflatable component was located between the structural and the convenience layers. Alternately, the inflatable portion may be the “A” surface layer, or a backside layer. [0023] With regard to the inflatable layer itself, it is illustrated as having a non-inflatable center surrounded by a plurality of inflatable portions, some of which are connected by narrow air flow passageways. Neither a plurality of portions or passageways are required. For example, the inflatable portions could be one sack or bag around the entire periphery (thereby eliminating the air passageways) or a larger number of inflatable portions can be provided than are illustrated. Furthermore, the portions can extend further toward the center of the air bag layer than is shown in the drawings. Moreover, if roof bows are located in the vehicle, inflatable portions can be located beneath them for reasons discussed in greater detail below. Also, the number of ignitors (which are well known in and of themselves and which create a large volume of inert gas, such as nitrogen, at the time a remotely located sensor detects a sudden deceleration or impact) can be variously located within the inflatable headliner system. In the illustration, a single ignitor is illustrated on one side, but a similar ignitor can be located on the opposite side and the number can be variously selected by those familiar with air bag design. Moreover, the ignitor(s) can be located in a variety of areas, e.g., in the “A”, “B”, “C” or “D” pillars of the vehicle, or in the front or rear headers, or in the side rails. [0024] Additionally, it should be made very clear that the illustrated system is shown with each of four layers formed for a particular vehicle (e.g. by thermoforming). The inflatable component can be integrated in a wide variety of locations and shapes. [0025] Finally, the materials used for the construction of the inflatable layer, both the inflatable and non-inflatable portions thereof, can be selected from any of those currently in use for front impact or side impact air bags. The preferred material is a fabric, some of which is formed into pockets. The fabric may be nylon or other natural or synthetic woven or non-woven fabrics. [0026] Proceeding now to the description of the preferred embodiment, the FIGURE illustrates an inflatable headliner system 10 of the type which would be used with an SUV. As mentioned above, system 10 could be configured and dimensioned to be used with cars, SUVs, vans, light trucks, i.e. any vehicle which has a roof and a headliner system located between the roof and vehicle occupants. [0027] The illustrated system 10 is shown to include three conventional headliner layers, namely an inner fabric layer 12 , an intermediate structural foam layer 14 and a reinforcement or convenience layer 16 . Each layer is formed for structural or aesthetic purposes, as is very well known in the vehicle headliner art. For example, layers 12 , 14 and 16 (as well as the inflatable layer to be described layer) can be simultaneously or individually thermoformed (if materials which soften upon the application of heat are used), or they may be laid up, sprayed, molded or constructed using these or other known headliner fabrication methods. The layers 12 , 14 and 16 , in and of themselves, are well known and further details about them need not be provided here. [0028] The exploded view of the FIGURE shows layers 12 , 14 , and 16 to be separate from one another, but they could be combined (in various subcombinations) or some of the layers might be eliminated in their entirety or other layers added. All that is really required for the present invention is a layer (which may even be the inflatable layer to be discussed below) which can deform toward the vehicle occupant(s) and away from the vehicle roof at the time inflation and occupant protection is called for. [0029] As far as materials are concerned, the individual layers can be made from fabrics, foams, fibers, molded fiberboard, corrugated paper or plastics, etc. or combinations of the foregoing materials, again as is well known in the art. [0030] Referring again to the FIGURE, a number of openings are formed in each of layers 12 , 14 and 16 to illustrate several common vehicle accessories, but not to in any way limit the number, sizes or location of such openings. At the center 18 of the front end 20 of the system 10 , an opening 22 is provided for a light or other overhead component (mirror, sun glasses holder, garage door opener, holder, etc.). On either side of the opening 22 , two additional openings 24 and 25 are provided for the pivoting and inboard couplers, respectively, for sun visors. A pair of grab handle attachment openings 28 are provided along the sides of each of layers 12 , 14 and 16 , and finally a coat hook attachment opening 30 is provided in the rear portion of each of the three layers 12 , 14 and 16 . The accessories are, in and of themselves, very well known and need not be described here. [0031] An inflatable layer 35 is shown in the FIGURE located in the preferred embodiment between fabric layer 12 and structural layer 14 . Air bag layer 35 is preferably pliable or thermoformable to allow it to conform to the shapes of the layers on either side of it, and it includes a center portion 37 and a periphery 39 . Located about periphery 39 are at least one, and preferably a plurality of, inflatable sacks 40 . The inflatable sacks 40 may be connected by air flow passageways 41 if desired, and the number of inflatable sacks 40 , their size and precise location can be varied by those skilled in the air bag art after they have read this specification. Inflatable sacks 40 are bladders or pockets which are collapsed until a gas is forced into them at the time deployment and headliner deformation is desired. [0032] Air bag ignition systems themselves are very well known, as are the sensors used to detect a deployment event. Accordingly details will not be provided here. What is shown in the FIGURE is an illustrative ignitor 42 and a wire 43 leading to a sensor (not shown). As stated earlier, the number of ignitors and the location thereof can vary. While in the preferred and illustrated embodiment, the ignitor 42 is shown as part of the inflatable layer 35 , one or more of them could be located in the “A”, B″, “C” or “D” pillars of the vehicle, or at any other suitable locations. [0033] One additional feature and embodiment will now be described, i.e. the use of additional inflatable sacks 51 if cross-bows are provided in the vehicle in which system 10 will be used. This is desirable in such vehicles because the roof structure at the location of the cross bows will be sufficiently rigid to allow deforming the inflatable layer 35 downwardly upon the occurrence of a deployment event. Unless cross bows are present, the roof metal of the vehicle may yield, reducing the downwardly directed force of the expanding sacks 51 . In the FIGURE, cross bow locations are illustrated by dashed lines 50 . [0034] While the present invention has been described in connection with a preferred and an alternate embodiment, it is not to be limited in any sense by such disclosures (size, configuration, relative dimensions, materials, numbers of components, etc.) but it is to be limited solely by the scope of the claims which follow.

An inflatable headliner system is mounted below a vehicle roof. It deforms upon an accident/impact toward vehicle occupants. In the preferred embodiment, inflatable portions surround a central section of an inflatable layer. Individual portions may be separated by passageways. If cross bows are employed in the vehicle roof structure, an embodiment utilizes inflatable portions beneath the cross bows.

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application claims priority based upon U.S. Provisional Patent Application Ser. No. 60/281,926 filed Apr. 6, 2001. [0002] This application is also related to U.S. patent application Ser. Nos. 10/ ______ (Atty. Docket No. 5181-89400) entitled “A Maximal Tile Generation Technique and Associated Methods of Designing and Manufacturing VLSI Circuits” and Ser. No. 10/ ______ (Atty. Docket No. 5181-89300) entitled “Active Region Management Techniques and Associated Methods of Designing and Manufacturing VLSI Circuits”, both of which were filed on______ , 2002, assigned to the Assignee of the present application and hereby incorporated by reference as if reproduced in their entirety. BACKGROUND [0003] 1. Technical Field [0004] This relates to the design and manufacture of very large scale integrated (“VLSI”) circuits and, more particularly, to a method for routing connections between component tiles of a VLSI circuit suitable for use in conjunction with the design and manufacture of VLSI circuits. [0005] 2. Description of the Relevant Art [0006] A VLSI circuit is typically composed of a plurality of generally horizontal layers, each layer having a plurality of generally rectangular shaped components positioned thereon. VLSI circuit designers commonly refer to these generally rectangular shaped components as “component tiles” and to the rectangular shaped open spaces that surround the component tiles as “space tiles.” Component tiles that are to be connected on a VLSI circuit are said to form a “net”, while any component tile not connected to a particular net is considered to be an obstruction to that net. Two tiles are said to be “adjacent” if they touch along their edges and “overlapping” if there is even a single point located within the interior of both tiles. A set of tiles positioned within a routing area is said to be “maximal” if no two tiles are either overlapping or adjacent on their left or right edges. [0007] One step in the design of a VLSI circuit is to select the wire paths that extend through the space tiles to connect the electrically equivalent component tiles that form nets. A current technique used to determine these paths utilizes a tile expansion algorithm. More specifically, clear space around the component tiles forming a net is fractured into maximal space tiles. Adjoining ones of these maximal space tiles are used to define the most efficient tile path between two components. The path of the actual connection between the components, known as the wire path, is then defined as the route through the space tile path from the center of the component source tile to the center of the component destination tile. [0008] The aforementioned technique for selecting the wire paths for a VLSI circuit design suffers from two drawbacks, both of which may add to the cost of VLSI circuits manufactured in accordance with the design. First, if defined in accordance with the above-described manner, a tile path is not necessarily the optimal tile path through the clear space. Second, since the width of a tile path is typically much larger than the width of a wire path, multiple wire paths may exist through a given tile path. If the wire path located within the tile path is arbitrarily selected, the selected wire path is not necessarily the most efficient wire path potentially located within the tile path. SUMMARY [0009] Disclosed herein is a method and associated apparatus for the design and manufacture of VLSI circuit which incorporates therein a method for routing connections between component tiles of the VLSI circuit being designed. In accordance with the disclosed method, maximal component tile and maximal space tile lists are constructed and, from the constructed lists, the maximal component and maximal space tiles are positioned on the routing area(s). Optimal tile path and minimum cost wire path between pins that are CTs to be connected are determined and, utilizing the determined wire path, a VLSI circuit design is generated. The minimum cost path from a starting tile S to a destination tile T is determined by creating a priority queue and a search tree ST with the starting tile S as its root. While the priority queue is not empty, a low cost tile E neighboring the starting tile S is popped and, if a tile path to destination tile T is found, the cost of the tile path is evaluated and saved as the minimum cost point path. Otherwise, for each tile F neighboring the tile E, the search tree is expanded and, for a tile path having an estimated cost greater than the current cost, the search path is pruned. Otherwise, the search is expanded by adding the tile F (with corresponding minimum cost CE)) to the priority queue Q and inserting the tile F into the search tree as a child node of the tile E. BRIEF DESCRIPTION OF THE DRAWINGS [0010] [0010]FIG. 1 is a block diagram of a computer system in which VLSI circuit design software resides. [0011] [0011]FIG. 2 is a flow chart of a method for designing and manufacturing VLSI circuits. [0012] [0012]FIG. 3 a is a flow chart of a method, suitable for use with the method of designing and manufacturing VLSI circuits of FIG. 2, for reconfiguring a routing area into an arrangement of maximal component tiles and maximal space tiles. [0013] [0013]FIGS. 3 b - 1 through 3 b - 2 is a flow chart of a method, suitable for use with the method of designing and manufacturing VLSI circuits of FIG. 2, of determining an optimal tile path and minimum cost wire path between pins that are CTs to be connected. [0014] [0014]FIG. 4 is a top view of first and second routing areas, each forming a respective layer of a VLSI circuit design and having at least one component tile to be connected into a net. [0015] [0015]FIG. 5 is a top view of the first routing area of FIG. 4 after reconfiguration into an arrangement of maximal component tiles and maximal space tiles. [0016] [0016]FIG. 6 is a top view of the second routing area of FIG. 4 after reconfiguration into an arrangement of maximal component tiles and maximal space tiles. DETAILED DESCRIPTION [0017] Referring first to FIG. 1, a computer system 1 , for example, a personal computer (“PC”), file server or other type of computer, in which VLSI circuit design software resides will now be described in greater detail. The computer system 1 is comprised of a processor subsystem 2 , a memory subsystem 3 and an input/output (“I/O”) subsystem 4 coupled together by a bus subsystem 5 . The bus subsystem 5 encompasses the main system bus and any local or other types of busses that collectively couple the processor subsystem 2 , the memory subsystem 3 and the I/O subsystem 4 to one another. As used herein, the terms “couple” or “coupled” refer broadly to either a direct or an indirect connection between the referenced elements. [0018] The processor subsystem 2 encompasses the collective processing capability of the computer system 1 , including the central processing unit (“CPU”) as well as any secondary processing devices, for example, an arithmetic processing unit, coupled to the CPU by the bus subsystem 5 . Similarly, the memory subsystem 3 encompasses the collective storage capability of the computer system 1 , including main, auxiliary, cache and any other memory accessible by the processor subsystem 2 via the bus subsystem 5 . Finally, the I/O subsystem 4 encompasses any and all I/O devices, for example, floppy, CD-ROM or DVD drives, coupled to the bus subsystem 5 , for writing data to or reading data from the processor subsystem 2 or the memory subsystem 3 . The I/O subsystem 4 also encompasses any data communications equipment (“DCE”), for example, network interface cards or modems, which couple the computer system 1 to data terminal equipment (“DTE”), for example, a second PC, file server or web server, via a local area network (“LAN”), wide area network (“WAN”), intranet, internet or other type of network. [0019] [0019]FIG. 1 further shows plural software modules, specifically, a first software module 6 for providing the computer system 1 with VLSI circuit design functionality, a second software module 7 for providing the computer system 1 with maximal tile generation functionality, a third software module 8 for providing the computer system 1 with active region management functionality and a fourth software module 9 for providing the computer system 1 with connection routing functionality. Each of the software modules 6 through 9 is comprised of a series of instructions which are encoded in the memory subsystem 3 as computer readable program code and executable by the processor subsystem 2 . Typically, the VLSI circuit design module 6 , the maximal tile generation module 7 , the active region management module 8 and the connection routing module 9 will be stored in the auxiliary memory of the memory subsystem 3 prior to the execution thereof. A transportable computer usable medium 10 , for example, a floppy disk, CD-ROM or file transfer software, is used to copy the VLSI circuit design module 6 , the maximal tile generation module 7 , the active region management module 8 and the connection routing module 9 into the auxiliary memory of the memory subsystem 3 . [0020] As illustrated in FIG. 1, the functionality provided by the software modules 6 through 9 may be encoded in the memory subsystem 3 and/or the computer usable medium 10 as discrete computer programs, each containing computer readable program code. Alternately, the functionality provided by the software modules 6 through 9 may be encoded in the memory subsystem 3 and/or the computer usable medium 10 as separate subroutines of a single computer program containing plural computer readable program subcodes. Furthermore, while any of the software modules 6 through 9 may be executed separately, typically, the VLSI circuit design module 6 will be initially executed by the processor subsystem 3 . The VLSI circuit design module 6 will then periodically call selected ones of the maximal tile generation module 7 , the active region management module 8 and the connection routing module 9 to perform certain functions during the design of a VLSI circuit. Of course, any one of the software modules 6 through 9 may call any other one of the software modules 6 through 9 to perform certain functions on its behalf. [0021] Referring next to FIG. 2, a method for designing and manufacturing VLSI circuits will now be described in greater detail. The method commences at step 11 with the execution of the VLSI circuit design module 6 by the processor subsystem 2 . The method proceeds to step 12 where one or more routing areas are defined and a collection of component tiles are positioned on each routing area using the VLSI circuit design module 6 . Generally, a routing area comprises the surface area of a layer of an integrated circuit on which component tiles are positioned. When plural routing areas are defined by the VLSI circuit design module 6 , the integrated circuit being designed is a multi-layer integrated circuit and each routing area comprises the surface of a respective layer of the multi-layer integrated circuit. [0022] For example, FIG. 4 illustrates the components tiles (“CT”s) of a multi-layer integrated circuit design having two layers. The CTs 92 , 94 and 96 are positioned within a first routing area 90 of a first, or upper, layer. Also shown in FIG. 4 is CT 98 , which is illustrated in phantom because it resides on a second routing area 90 ′ of a second, or lower, layer located beneath the routing area 90 . In the VLSI circuit design illustrated in FIG. 4, the CTs 92 , 96 and 98 , also known as pins, are on the same net while the CT 94 is an obstruction. Thus, the CTs 92 , 96 and 98 must now be connected while avoiding the CT 94 . [0023] While, in the description to follow, the routing areas 90 and 90 ′ are oftentimes described with respect to a vertical axis, hereafter termed the “S” axis, which extends from S 0 to S 8 , and a horizontal axis, hereafter termed the “D” axis, which extends from D 0 to D 9 , it should be clearly understood that the use of these terms is not intended to imply or suggest that the routing areas 90 and 90 ′ have a particular orientation, either horizontal or vertical, relative to the VLSI circuit being designed. Likewise, the description of a first span (or segment thereof) of the routing areas 90 or 90 ′ as being located above or below a second span (or segment thereof) is not intended to imply or suggest that the first and second spans are oriented in either the horizontal or vertical plane. Rather, the use of these terms is merely intended to describe their relative location within a common plane without regard to the specific orientation of that plane. [0024] Accordingly, the method proceeds to step 14 where the first routing area 90 is selected for reconfiguration into maximal component and space tiles. The method then continues on to step 16 for construction of maximal component tile and maximal space tile lists for the routing area 90 . The CTs 92 , 94 and 96 of the routing area 90 are all maximal component tiles because there are no overlapping tiles or adjacent tiles on either the left or right sides thereof. However, the open space of the routing area 90 needs to be divided into one or more maximal space tiles. A suitable method to perform this operation is disclosed in co-pending U.S. patent application Ser. No. 10/ ______ (Atty. Docket No. 5181-89400) entitled “A Maximal Tile Generation Technique and Associated Methods of Designing and Manufacturing VLSI Circuits” and previously incorporated by reference. However, as the current example differs from that described in the above-referenced patent application in that all of the component tiles positioned on the routing area 90 are already maximal component tiles, the method set forth in the above-referenced application shall later be applied to the routing area 90 illustrated in FIG. 4. [0025] After constructing maximal component tile and maximal space tile lists for the routing area 90 in a manner to be more fully described below, the method proceeds to step 17 where it is determined if there are additional routing area for which maximal component tile and maximal space tile lists are to be constructed. As maximal component tile and maximal space tile lists must still be constructed for the routing area 90 ′, the method proceeds to step 18 for selection of the routing area 90 ′ and then returns to step 16 for construction of maximal component tile and maximal space tile lists for the routing area 90 ′. After constructing maximal component tile and maximal space tile lists for the routing area 90 ′ in a manner to be more fully described below, the method proceeds to step 17 where it is determined that maximal component tile and maximal space tile lists have been constructed for all routing areas. Accordingly, the method then proceeds to step 19 where the maximal component tile and maximal space tile lists constructed at step 16 are used to position the maximal component tiles and the maximal space tiles on the routing areas 90 , 90 ′. [0026] After positioning the maximal component and maximal space tiles on the routing areas 90 , 90 ′, the method proceeds to step 20 where the connection routing module 9 determines the optimal tile path and minimum cost wire path between pins that are CTs to be connected. Using the minimum cost wire path between pins that are CTs to be connected, the method continues on to step 24 where the positions of the CTs and the wire path interconnecting the connected CTs are used by the VLSI circuit design module 6 to produce a VLSI circuit design. It should be noted, however, that the foregoing description of a method of designing a VLSI circuit is highly simplified and that numerous steps in the process which are deemed as not being needed for an understanding of the disclosed techniques have been omitted for ease of description. Having completed the design of the VLSI circuit, the method then continues on to step 26 where plural VLSI circuits which conform to the design are manufactured at a facility using conventional manufacturing processes. The method then ends at step 28 . [0027] Turning now to FIG. 3 a , the method by which maximal component tile and maximal space tile lists are determined for the routing area 90 at step 16 will now be described in greater detail. The method commences at step 30 and, at step 32 , a list (AL) of active segments and a list (IL) of inactive segments of a span which extends along a bottom edge 90 a of the routing area 90 are identified. Generally, an “active” segment of a span is a segment which passes through the interior of a component tile or along a lower edge thereof. Conversely, an “inactive” segment of a span is a segment that passes through an unoccupied portion of the routing area or along an upper edge of a component tile. Once active and inactive segments of the span have been identified, a level is then assigned to each segment thereof. The level of a segment is the point, along the S axis, generally aligned with the span of which the active or inactive segment forms a portion thereof. For example, a segment forming part of a span may be described as follows: [DX, DY, SZ] where DX is the point, along the D axis, where the active or inactive segment starts, DY is the point, along the D axis, where the active or inactive segment ends and SZ is the level, along the S axis, of the active or inactive span of which the active or inactive segment forms a portion thereof. [0028] An active segment of a first span may be said to “match” an active segment of a second span if the segments have the same start point DX and the same stop point DY along the D axis but different levels SZ along the S axis. For example, the active segments [D 1 , D 3 , S 1 ] and [D 1 , D 3 , S 2 ] are considered to be matching active segments. Conversely, the term “unmatched” active segments refer to spans which, in addition to having different levels SZ, also have different start points DX, different stop points DY or both. Likewise, an inactive segment of a first span matches an inactive segment of a second span if the segments have the same start and stop points DX and DY but different levels SZ while unmatched inactive segments also have either a different start point DX, a different stop point DY or both. [0029] A “characteristic” of a span is defined by the set of segments which comprises the span. A pair of spans may be deemed as having the same characteristic if every active and inactive segment of a first span of the span pair has a matching active or inactive segment, respectively, in a second one of the span pair. Conversely, a pair of spans may be deemed as having different characteristics if every active and inactive segment of the first span fails to have a matching active or inactive segment, respectively, in the second span. [0030] As may be clearly seen in FIG. 4, neither a lower edge nor an interior of a component tile extends along the bottom edge 90 a of the routing area 90 . Accordingly, the bottom edge 90 a of the routing area 90 has a span comprised of a single inactive segment which extends from DO to D 9 . As may be further seen in FIG. 4, the level of the span is SO. The level of the span is hereby designated as a first stop point SO for a set of stop points for the routing area 90 and the list of active and inactive segments of the span which extends along the bottom edge 90 a of the routing area 90 and is generally aligned with the first stop point SO may be described as follows: AL=Φ; and IL={[D 0 , D 9 , SO]}. [0031] The list of ALs and the list of ILs for the span generally aligned with the first stop point S 0 are hereby designated as a current list of ALs and a current list of ILs, respectively, for the routing area 90 . [0032] Continuing on to step 34 , additional members of the set of stop points for the routing area 90 are identified. These additional stop points for the routing area 90 are those points along the S axis which are generally aligned with either a lower edge of one or more of the CTs 92 , 94 and 96 and/or an upper edge of one or more of the CTs 92 , 94 and 96 . Thus, from the known arrangement of the CTs 92 , 94 and 96 illustrated in FIG. 4, the maximal tile generation module 7 identifies, in an ascending order relative to the S axis, S 1 , S 2 , S 3 , S 4 , S 5 and S 6 as additional members of the set of stop points for the routing area 90 . Finally, an upper edge 90 b of the routing area 90 is designated as a last stop point S 8 of the set of stop points for the routing area 90 . The method then proceeds to step 36 where an empty list of maximal component tiles (CTL) and an empty list of maximal space tiles (STL) are generated. [0033] S 1 , S 2 , S 3 , S 4 , S 5 and S 6 were identified as additional stop points because they are all aligned with one or more of the lower edges of the CTs 92 , 94 and 96 and/or the upper edges of the CTs 92 , 94 and 96 . The edges of the CTs 92 , 94 and 96 are used to identify additional stop points since the edges of a CT indicate transition between active and inactive regions. More specifically, a lower edge of a CT indicates the location of an inactive-to-active transition while an upper edge of a CT indicates the location of an active-to-inactive transition. The stop points are selected to coincide with either inactive-to-active or active-to-inactive transitions because, in accordance with the techniques disclosed herein and to be more fully described below, maximal component and/or space tiles are generated whenever active and/or inactive segments of a first span fails to have a matching active and/or inactive segments along a second span. [0034] At step 38 , it is determined whether there are additional stop points which require examination. If so, the method proceeds to step 40 for selection of a next stop point for examination. At step 42 , a next list of active segments and a next list of inactive segments are identified for a next span generally aligned with a next stop point of the set of stop points. The lists of active and inactive segments of the span generally aligned with the next stop point are generated using the active region management techniques disclosed in co-pending U.S. patent application Ser. No. 10/ ______ (Atty. Docket No. 5181-89300) entitled “Active Region Management Techniques and Associated Methods of Designing and Manufacturing VLSI Circuits” and previously incorporated by reference. Once the next list of active segments and the next list of inactive segments of the span generally aligned with the next stop point have been generated at step 42 , the method proceeds to step 44 where the next list of active segments is compared to the current list of active segments and, based upon that comparison, one or more maximal component tiles may be identified for inclusion in the list of maximal component tiles. [0035] More specifically, for each active segment S in the current list of active segments, the next list of active segments is examined for a matching active segment S'. If there is no matching active segment S' in the next list of active segments, a maximal component tile having a width generally equal to the width [DX, DY] of the active segment S and a height generally equal to the difference between the level of the active segment S and the level of the active segment S' is generated. The generated maximal component tile is then inserted into the maximal component tile list CTL and the active segment S removed from the current list of active segments. After searching for a matching active segment S' in the next active segment list for each active segment S in the current active segment list, any unmatched active segment S' in the next active segment list is added to the current active segment list. Initially, the current active segment list will contain active segments at only one level. It should be noted, however, as the next active segment lists for various levels are examined, the current active segment list will likely contain active segments at plural levels. [0036] The method then proceeds to step 46 where the process of step 45 is repeated using the current and next list of inactive segments. By doing so, one or more maximal space tiles may be generated at step 44 and added to the maximal space tile list STL. Additionally, the current list of inactive segments will be modified by deleting the inactive segments, from the current list of inactive segments, the inactive segments having a matching inactive segment in the next list of inactive segments and by adding, to the current list of inactive segments, unmatched inactive segments from the next list of inactive segments. The method then returns to step 38 where the process described in steps 40 , 42 , 44 and 46 is repeated for each stop point in the set of stop points. After the last stop point in the set of stop points has been processed, the method will proceed from step 38 to step 48 where the maximal component tile list CTL and the maximal space tile list STL generated by the described method are output, typically, to the VLSI circuit design module 8 for use in connection with the design and manufacture of a VLSI circuit in accordance with the method of FIG. 2. [0037] The above-described method of generating a list of maximal component tiles CTL and a list of maximal space tiles STL for the routing area 90 shall again be described, now with respect to the example illustrated in FIGS. 4 and 5. As previously noted, FIG. 4 shows the CTs 92 , 94 and 96 positioned in the routing area 90 . As previously set forth, the process starts at step 32 by identifying the active and inactive segments for a span extending along the bottom edge 90 a of the routing area 90 . As there are no active segments along the bottom edge 90 a, the active and inactive segment lists for this span, which is generally aligned with the stop point SO, are initially set as follows: AL=Φ; and IL={[D 0 , D 9 , SO]}. [0038] At step 34 , the remaining members of the set of stop points are identified (S 1 , S 2 , S 3 , S 4 , S 5 , S 6 and S 8 ) and, at step 36 , an empty maximal component tile list CTL and an empty maximal space tile list STL are generated. As the stop points S 1 , S 2 , S 3 , S 4 , S 5 , S 6 and S 8 need to be examined, the method passes through 38 and on to step 40 where the stop point SI, the next stop point after the stop point S 0 , is selected for examination. As may be seen in FIG. 4, bottom edge 96 a of the CT 96 is generally aligned with the stop point S 1 . The corresponding segment is, therefore, considered to be active while the remaining segments generally aligned with the stop point S 1 are considered to be inactive. Accordingly, at step 42 , the next list of active segments and the next list of inactive segments are determined to be: AL=Φ; and IL={[D 0 , D 9 , SO]}. [0039] Proceeding to step 44 , the current active segment list is empty. As a result, there are no matches between the current list of active segments and the next list of active segments. As a result, no maximal component tiles are generated at step 44 . Furthermore, as the entry in the next active segment list is unmatched, it is added to the current active segment list, which now becomes: AL={[D 6 , D 8 , S 1 ]}. [0040] The method then proceeds to step 46 for processing of the current inactive segment list. The current inactive segment list contains a single entry [D 0 , D 9 , S 0 ]. As there is no matching span in the next inactive segment list, a space tile, hereafter referred to as ST 100 and illustrated in FIG. 5, which extends from D 0 to D 9 in the D axis along a line generally aligned with S 0 and which extends from S 0 to S 1 in the S axis is generated and added to the maximal space tile list STL. The matched entry [D 0 , D 9 , S 0 ] is deleted from the current inactive segment list and the unmatched entries [D 0 , D 6 , S 1 ] and [D 8 , D 9 , S 1 ] of the next inactive segment list are added to the inactive segment list, thereby producing the following current inactive segment list: IL={[D 0 , D 6 , S 1 ], [D 8 , D 9 , S 1 ]}. [0041] The method then returns to step. 38 and, as there are additional stop points to be examined, on to step 40 where stop point S 2 is selected for examination. [0042] A span extending across the routing area 90 along a line generally aligned with the stop point S 2 passes along a lower edge 94 a of the CT 94 and through the interior of the CT 96 . Accordingly, the next list of active and inactive segments would be as follows AL={[D 3 , D 4 , S 2 ], [D 6 , D 8 , S 2 ]}; and IL={[D 0 , D 3 , S 2 ], [D 4 , D 6 , S 2 ], [D 8 , D 9 , S 2 ]}. [0043] For each active segment in the current active segment list, the next active segment list is searched for matches. Here, [D 6 , D 8 , S 1 ], currently the only entry in the current active segment, matches the [D 6 , D 8 , S 2 ] entry from the next active segment list. Accordingly, no maximal component tiles are generated during step 44 . The matched entry [D 6 , D 8 , S 2 ] is deleted from the next active segment list while the unmatched entry [D 3 , D 4 , S 2 ] from the next active segment list is added to the current active segment list, thereby producing the following current active segment list: AL={[D 3 , D 4 , S 2 ], [D 6 , D 8 , S 1 ]}. [0044] The method then proceeds to step 46 for processing of the current inactive segment list. The current inactive segment list contains entries [D 0 , D 6 , S 1 ] and [D 8 , D 9 , S 1 ] while the next inactive segment list contains entries [D 0 , D 3 , S 2 ], [D 4 , D 6 , S 2 ] and [D 8 , D 9 , S 2 ]. Thus, the [D 8 , D 9 , S 1 ] entry of the current inactive segment list is matched while the [D 0 , D 6 , S 1 ] entry is unmatched. Accordingly, maximal space tile ST 102 , which extends from D 0 to D 6 in the D axis along a line generally aligned with SI, extends from S 1 to S 2 in the S axis and is illustrated in FIG. 5, is generated and added to the maximal space tile list STL. The unmatched entry is then deleted from the current inactive segment list while the unmatched entries [D 0 , D 3 , S 2 ] and [D 4 , D 6 , S 2 ] of the next inactive segment list is added to the current inactive segment list, thereby producing the following current inactive segment list: IL={[D 0 , D 3 , S 2 ], [D 4 , D 6 , S 2 ], [D 8 , D 9 , S 1 ]}. [0045] A span extending across the routing area 90 along a line generally aligned with the stop point S 3 passes through the interior of the CT 94 and along an upper edge 96 b of the CT 96 . Accordingly, the next list of active and inactive spans would be as follows: AL={[D 3 , D 4 , S 3 ]}; and IL ={[DO, D 3 , S 3 ], [D 4 , D 9 , S 3 ]}. [0046] For each active span in the current active segment list, the next active segment list is searched for matches. Here, the entry [D 3 , D 4 , S 2 ] matches the entry [D 3 , D 4 , S 3 ] while the entry [D 6 , D 8 , S 1 ] is unmatched. Accordingly, the entry [D 6 , D 8 , S 1 ] is used to generate a maximal component tile, hereafter referred to as CT 104 and illustrated in FIG. 5, which extends from D 6 to D 8 in the D axis along a line generally aligned with Si and from S 1 to S 3 in the S axis. The newly generated maximal component tile is then added to the maximal component tile list CTL. The unmatched entry [D 6 , D 8 , S 1 ] is deleted from the current active segment list and, since there are no unmatched entries from the next active segment list, the following current active segment list is produced: AL={[D 3 , D 4 , S 2 ]}. [0047] The method then proceeds to step 46 for processing of the current inactive segment list. The current inactive segment list contains entries [D 0 , D 3 , S 2 ], [D 4 , D 6 , S 2 ] and [D 8 , D 9 , S 1 ] while the next inactive segment list contains entries [D 0 , D 3 , S 3 ] and [D 4 , D 9 , S 3 ]. Thus, the [D 4 , D 6 , S 2 ] and [D 8 , D 9 , S/I] entries of the current inactive segment list are unmatched while the [D 0 , D 3 , S 2 ] entry of the current inactive segment list is matched. Accordingly, the unmatched entry [D 4 , D 6 , S 2 ] is used to generate maximal space tile ST 106 , which extends from D 4 to D 6 in the D axis along a line generally aligned with S 2 , extends from S 2 to S 3 in the S axis and is illustrated in FIG. 5. Similarly, the unmatched entry [D 8 , D 9 , SI] is used to generate maximal space tile ST 108 , which extends from D 8 to D 9 in the D axis along a line generally aligned with S 2 , extends from S 1 to S 3 in the S axis and is illustrated in FIG. 5. The newly generated tiles are then added to the maximal space tile list, the unmatched entries [D 4 , D 6 , S 2 ] and [D 8 , D 9 , S 1 ] are deleted from the current inactive segment list and the unmatched entry [D 4 , D 9 , S 3 ] of the next inactive segment list is added to the current inactive segment list, thereby producing the following current inactive segment list: IL={[D 0 , D 3 , S 2 ], [D 4 , D 9 , S 3 ]}. [0048] The method then returns to step 38 and, as there are additional stop points to be examined, on to step 40 where stop point S 4 is selected for examination. [0049] A span extending across the routing area 90 along a line generally aligned with the stop point S 4 along a lower edge 92 a of the CT 92 and through the interior of the CT 94 . Accordingly, the next list of active and inactive spans generated at step 42 would be as follows: AL={[D 1 , D 2 , S 4 ], [D 3 , D 4 , S 4 ]}; and IL {[DO, D 1 , S 4 ], [D 2 , D 3 , S 4 ], [D 4 , D 9 , S 4 ]}. [0050] The current and next active segment lists are then processed at step 44 . The current active segment list is [D 3 , D 4 , S 2 ] while the next active segment list is [D 1 , D 2 , S 4 ], [D 3 , D 4 , S 4 ]. Thus, [D 3 , D 4 , S 2 ], the only member of the current active segment list, matches [D 3 , D 4 , S 4 ] of the next active segment list while [D 1 , D 2 , S 4 ] of the next active segment lists is unmatched. Accordingly, at step 44 , no maximal component tiles are generated and no entries are deleted while [D 1 , D 2 , S 4 ] is added to the current active segment list, thereby producing the following current active segment list: AL={[D, D 2 , S 4 ], [D 3 , D 4 , S 2 ]}. [0051] The method then proceeds to step 46 for processing of the current inactive segment list. The current inactive segment list contains entries [D 0 , D 3 , S 2 ] and [D 4 , D 9 , S 3 ] while the next inactive segment list contains entries [D 0 , D 1 , S 4 ], [D 2 , D 3 , S 4 ] and [D 4 , D 9 , S 4 ]. Thus, the [D 4 , D 9 , S 3 ] entry of the current inactive segment list is matched to the entry [D 4 , D 9 , S 4 ] entry of the next inactive segment list while the [D 0 , D 3 , S 2 ] entry of the current inactive segment list and the [D 0 , D 1 , S 4 ] and [D 2 , D 3 , S 4 ] entries of the next inactive segment list are unmatched. Accordingly, the unmatched entry [D 0 , D 3 , S 2 ] of the current active span is used to generate maximal space tile ST 110 , which extends from D 0 to D 3 in the D axis along a line generally aligned with S 2 , extends from S 2 to S 4 in the S axis and is illustrated in FIG. 5. The newly generated space tile is then added to the maximal space tile list STL, the unmatched entry [D 0 , D 3 , S 2 ] is deleted from the current inactive segment list and the unmatched entries [D 0 , D 1 , S 4 ] and [D 2 , D 3 , S 4 ] of the next inactive segment list is added to the current inactive segment list, thereby producing the following current inactive segment list: IL={[D 0 , D 1 , S 4 ], [D 2 , D 3 , S 4 ], [D 4 , D 9 , S 3 ]}. [0052] The method then returns to step 38 and, as there are additional stop points to be examined, on to step 40 where stop point S 5 is selected for examination. [0053] A span extending across the routing area 90 along a line generally aligned with the stop point S 5 passes through the interior of the CT 92 and along the upper edge 94 b of the CT 94 . Accordingly, the next list of active and inactive spans generated at step 42 would be as follows: AL={[D, D 2 , S 5 ]; }and IL={[D 0 , D 1 , S 5 ], [D 2 , D 9 , S 5 ]}. [0054] The current and next active segment lists are then processed at step 44 . The current active segment list is [D 1 , D 2 , S 4 ] and [D 3 , D 4 , S 2 ] while the next active segment list is [D 1 , D 2 , S 5 ]. Thus, the [D 1 , D 2 , S 4 ] entry of the current active segment list matches the [D 1 , D 2 , S 5 ] entry of the next active segment list while the [D 3 , D 4 , S 2 ] entry of the current active segment list is unmatched. Accordingly, the [D 3 , D 4 , S 2 ] of the current active segment list is used to generate a maximal component tile, hereafter referred to as CT 112 , which extends from D 3 to D 5 in the D axis along a line generally aligned with the stop point S 4 and from the stop point S 2 to the stop point S 5 in the S axis, and is illustrated in FIG. 5. The newly generated maximal component tile is then added to the maximal component tile list CTL. The unmatched entry [D 3 , D 4 , S 2 ] is then deleted from the current active segment list and the matched entry [D 1 , D 2 , S 5 ] is deleted from the next active segment list, thereby resulting in the following current active segment list: AL={[D 1 , D 2 , S 4 ]}. [0055] The method then proceeds to step 46 for processing of the current inactive segment list. The current inactive segment list contains entries [D 0 , D 1 , S 4 ], [D 2 , D 3 , S 4 ] and [D 4 , D 9 , S 3 ] while the next inactive segment list contains the entries [D 0 , D 1 , S 5 ] and [D 2 , D 9 , S 5 ]. Thus, the [D 2 , D 3 , S 4 ], [D 4 , D 9 , S 3 ] entries of the current inactive segment list and the [D 2 , D 9 , S 5 ] entry of the next inactive segment list are unmatched. Accordingly, the unmatched entry [D 2 , D 3 , S 4 ] of the current inactive span is used to generate maximal space tile ST 114 , which extends from D 2 to D 3 in the D axis along a line generally aligned with S 4 and which extends from S 4 to S 5 in the S axis while the unmatched entry [D 4 , D 9 , S 3 ] of the current inactive span is used to generate maximal space tile ST 116 which extends from D 4 to D 9 in the D axis along a line generally aligned with S 3 and which extends from S 3 to S 5 in the S axis. The newly generated space tiles ST 114 and ST 116 , both of which are illustrated in FIG. 5, are then added to the maximal space tile list STL, the unmatched entries [D 2 , D 3 , S 4 ] and [D 4 , D 9 , S 3 ] are deleted from the current inactive segment list and the unmatched entry [D 2 , D 9 , S 5 ] of the next inactive segment list is added to the current inactive segment list, thereby producing the following current inactive segment list: IL={[D 0 , D 1 , S 4 ], [D 2 , D 9 , S 5 ]}. [0056] The method then returns to step 38 and, as there are additional stop points to be examined, on to step 40 where the stop point S 6 is selected for examination. [0057] A span extending across the routing area 90 along a line generally aligned with the stop point S 6 passes along the upper edge 92 b of the CT 92 . Accordingly, the next list of active and inactive spans generated at step 42 would be as follows: ALΦ; and IL={[D 0 , D 9 , S 6 ]}. [0058] The current and next active segment lists are then processed at step 44 . The current active segment list is [D 1 , D 2 , S 4 ] while the next active segment list is empty. Thus, the [D 1 , D 2 , S 4 ] entry of the current active segment list is unmatched. Accordingly, the [D 1 , D 2 , S 4 ] of the current active segment list is used to generate a maximal component tile, hereafter referred to as CT 118 , which extends from D 1 to D 2 in the D axis along a line generally aligned with the stop point S 4 and from the stop point S 4 to the stop point S 6 in the S axis, and is illustrated in FIG. 5. The newly generated maximal component tile is then added to the maximal component tile list CTL. The unmatched entry [D 1 , D 2 , S 4 ] is then deleted from the current active segment list, thereby emptying the current active segment list and, since the next active segment list is empty as well, the current active segment list becomes the following: AL=Φ. [0059] The method then proceeds to step 46 for processing of the current inactive segment list. The current inactive segment list contains entries [D 0 , D 1 , S 4 ] and [D 2 , D 9 , S 5 ] while the next inactive segment list contains the entry [D 0 , D 9 , S 6 ]. Thus, the [D 0 , D 1 , S 4 ] and [D 2 , D 9 , S 5 ] entries of the current inactive segment list and the [D 0 , D 9 , S 6 ] entry of the next inactive segment list are unmatched. Accordingly, the unmatched entry [D 0 , D 1 , S 4 ] of the current inactive span is used to generate maximal space tile ST 120 , which extends from D 0 to D 1 in the D axis along a line generally aligned with S 4 and which extends from S 4 to S 6 in the S axis while the unmatched entry [D 2 , D 9 , S 5 ] of the current inactive span is used to generate maximal space tile ST 122 which extends from D 2 to D 9 in the D axis along a line generally aligned with S 5 and which extends from S 5 to S 6 in the S axis. The newly generated space tiles ST 120 and ST 122 , both of which are illustrated in FIG. 5, are then added to the maximal space tile list STL, the unmatched entries [D 0 , D 1 , S 4 ] and [D 2 , D 9 , S 5 ] are deleted from the current inactive segment list and the unmatched entry [D 0 , D 9 , S 6 ] of the next inactive segment list is added to the current inactive segment list, thereby producing the following current inactive segment list: IL={[D 0 , D 9 , S 6 ]}. [0060] The method then returns to step 38 and, as there are additional stop points to be examined, on to step 40 where the stop point S 8 is selected for examination. The stop point S 8 is generally aligned with an upper edge 90 b of the routing area 90 . As neither a lower edge nor an interior of a component is positioned along the upper edge 90 b , the next list of active and inactive spans generated at step 42 would be as follows: AL=Φ; and IL={ [D 0 , D 9 , S 7 ]}. [0061] The current and next active segment lists are then processed at step 44 . The current active segment list is Φ while the next active segment list is Φ. As both the current and next active segment lists are empty, no additional maximal component tiles are generated and the current active segment list remains empty. [0062] The method then proceeds to step 46 for processing of the current inactive segment list. The current inactive segment list contains the entry [D 0 , D 9 , S 6 ] while the next inactive segment list contains the entry [D 0 , D 9 , S 8 ]. While the current and inactive segment lists contain matching entries, the stop point being examined is the last stop point in the set of stop points. Accordingly, the [D 0 , D 9 , S 6 ] entry of the current inactive segment list is used to generate a maximal space tile, hereafter referred to as maximal space tile 124 , which extends from D 0 to D 9 in the D axis along a line generally aligned with S 6 , extends from S 6 to S 8 in the S axis and is illustrated in FIG. 5. The newly generated space tile is added to the maximal space tile list STL and the entry [D 0 , D 9 , S 6 ] of the current inactive segment list is deleted therefrom, thereby emptying it. Further, as the entry [D 0 , D 9 , S 8 ] was matched to the entry [D 0 , D 9 , S 6 ], it is not added to the current inactive segment list, thereby keeping the current inactive segment list empty. The method then returns to step 38 and as all of the stop points SO through S 6 and S 8 have been examined, to step 48 for output of the generated maximal component tile and maximal space tile lists CTL and STL to the VLSI circuit design module 6 . The method then ends at step 50 . [0063] Continuing to refer to FIG. 3 a , the method of generating a list of maximal component tiles CTL and a list of maximal space tiles STL for the routing area 90 ′, shall now be described, this time, in conjunction with FIGS. 4 and 6. As previously noted, FIG. 4 shows the CT 98 positioned in the routing area 90 ′. As before, the process starts at step 32 by identifying the active and inactive segments for a span extending along a bottom edge 90 a ′ of the routing area 90 ′. As there are no active segments along the bottom edge 90 a ′, the active and inactive segment lists for this span, which is generally aligned with the stop point SO, are initially set as follows: AL=Φ; and IL={[D 0 , D 9 , SO]}. [0064] At step 34 , the remaining members of the set of stop points are identified (S 5 and S 7 ) and, at step 36 , an empty maximal component tile list CTL and an empty maximal space tile list STL are generated. As the stop points S 5 , S 7 and S 8 need to be examined, the method passes through 38 and on to step 40 where the stop point S 5 , the next stop point after the stop point SO, is selected for examination. As may be seen in FIG. 4, bottom edge 98 a of the CT 98 is generally aligned with the stop point S 5 . The corresponding segment is, therefore, considered to be active while the remaining segments generally aligned with the stop point S 5 are considered to be inactive. Accordingly, at step 42 , the next list of active segments and the next list of inactive segments are determined to be: AL={[D 5 , D 7 , S 5 ]}; and IL={[D 0 , D 5 , S 5 ], [D 8 , D 9 , S 5 ]}. [0065] Proceeding to step 44 , the current active segment list is empty. As a result, there are no matches between the current list of active segments and the next list of active segments. As a result, no maximal component tiles are generated at step 44 . Furthermore, as the entry in the next active segment list is unmatched, it is added to the current active segment list, which now becomes: AL={[D 5 ,D 7 ,S 5 ]}. [0066] The method then proceeds to step 46 for processing of the current inactive segment list. The current inactive segment list contains a single entry [D 0 , D 9 , SO]. As there is no matching span in the next inactive segment list, a space tile, hereafter referred to as ST 200 and illustrated in FIG. 6, which extends from D 0 to D 9 in the D axis along a line generally aligned with S 0 and which extends from S 0 to S 5 in the S axis is generated and added to the maximal space tile list STL. The matched entry [D 0 , D 9 , S 0 ] is deleted from the current inactive segment list and the unmatched entries [D 0 , D 5 , S 5 ] and [D 8 , D 9 , S 5 ] of the next inactive segment list are added to the inactive segment list, thereby producing the following current inactive segment list: IL={[D 0 , D 5 , S 5 ], [D 8 , D 9 , S 5 ]}. [0067] The method then returns to step 38 and, as there are additional stop points to be examined, on to step 40 where stop point S 7 is selected for examination. [0068] A span extending across the routing area 90 ′ along a line generally aligned with the stop point S 7 passes along an upper edge 98 b of the CT 98 . Accordingly, the next list of active and inactive segments would be as follows AL=Φ; and IL={[D 0 , D 9 , SO]}. [0069] For each active segment in the current active segment list, the next active segment list is searched for matches. Here, [D 5 , D 7 , S 5 ], currently the only entry in the current active segment, is unmatched. Accordingly, the entry [D 5 , D 7 , S 5 ] is used to generate a maximal component tile, hereafter referred to as CT 202 and illustrated in FIG. 6, which extends from D 5 to D 7 in the D axis along a line generally aligned with S 5 and from S 5 to S 7 in the S axis. The newly generated maximal component tile is then added to the maximal component tile list CTL. The unmatched entry [D 5 , D 7 , S 5 ] is deleted from the current active segment list, thereby emptying it, and, since there are no unmatched entries from the next active segment list, the current active segment list remains empty as shown below: AL=Φ. [0070] The method then proceeds to step 46 for processing of the current inactive segment list. The current inactive segment list contains entries [D 0 , D 5 , S 5 ] and [D 7 , D 9 , S 5 ] while the next inactive segment list contains the entry [D 0 , D 9 , S 7 ]. Thus, the [D 0 , D 5 , S 5 ] and [D 7 , D 9 , S 5 ] entries of the current inactive segment list are unmatched. Accordingly, the unmatched entry [D 0 , D 5 , S 5 ] is used to generate maximal space tile ST 204 , which extends from D 0 to D 5 in the D axis along a line generally aligned with S 5 , extends from S 5 to S 7 in the S axis and is illustrated in FIG. 5. Similarly, the unmatched entry [D 7 , D 9 , S 5 ] is used to generate maximal space tile ST 206 , which extends from D 7 to D 9 in the D axis along a line generally aligned with S 5 , extends from S 5 to S 7 in the S axis and is illustrated in FIG. 5. The newly generated tiles are then added to the maximal space tile list, the unmatched entries [D 0 , D 5 , S 5 ] and [D 7 , D 9 , S 5 ] are deleted from the current inactive segment list and the unmatched entry [D 0 , D 9 , S 7 ] of the next inactive segment list is added to the current inactive segment list, thereby producing the following current inactive segment list: IL{[D 0 , D 9 , S 7 ]}. [0071] The method then returns to step 38 and, as there are additional stop points to be examined, on to step 40 where stop point S 8 is selected for examination. The stop point S 8 is generally aligned with an upper edge 90 b ′ of the routing area 90 ′. As neither a lower edge nor an interior of a component is positioned along the upper edge 90 b ′, the next list of active and inactive spans generated at step 42 would be as follows: AL=Φ; and IL={[D 0 , D 9 , SO]}. [0072] The current and next active segment lists are then processed at step 44 . The current active segment list is Φ while the next active segment list is Φ. As both the current and next active segment lists are empty, no additional maximal component tiles are generated and the current active segment list remains empty. [0073] The method then proceeds to step 46 for processing of the current inactive segment list. The current inactive segment list contains the entry [D 0 , D 9 , S 7 ] while the next inactive segment list contains the entry [D 0 , D 9 , S 8 ]. While the current and inactive segment lists contain matching entries, the stop point being examined is the last stop point in the set of stop points. Accordingly, the [D 0 , D 9 , S 7 ] entry of the current inactive segment list is used to generate a maximal space tile, hereafter referred to as maximal space tile 208 , which extends from D 0 to D 9 in the D axis along a line generally aligned with S 7 , extends from S 7 to S 8 in the S axis and is illustrated in FIG. 5. The newly generated space tile is added to the maximal space tile list STL and the entry [D 0 , D 9 , S 7 ] of the current inactive segment list is deleted therefrom, thereby emptying it. Further, as the entry [D 0 , D 9 , S 8 ] was matched to the entry [D 0 , D 9 , S 7 ], it is not added to the current inactive segment list, thereby keeping the current inactive segment list empty. The method then returns to step 38 and as all of the stop points S 0 , S 5 , S 7 and S 8 have been examined, to step 48 for output of the generated maximal component tile and maximal space tile lists CTL and STL to the VLSI circuit design module 6 . The method then ends at step 50 . [0074] Referring next to FIGS. 3 b - 1 through 3 b - 2 , the method of determining an optimal tile path and minimum cost wire path between pins that are CTs to be connected will now be described in greater detail. From the application of the method of FIG. 3a to the routing areas illustrated in FIG. 4, it has been determined that the CTs 118 , 104 and 202 are pins to be connected while the CT 112 is an obstruction to be avoided. The method commences at step 50 and, at step 52 , a starting tile S and a destination tile T are selected from amongst the CTs 118 , 104 and 202 . The method then proceeds on to step 54 where a priority queue Q is created and to step 56 where the starting tile S is inserted into the priority queue Q. The method then continues on to step 58 , where a search tree ST having the starting tile S as its root is generated and on to step 60 where an initial path cost C between starting tile S and destination tile T is set to infinity. [0075] Proceeding on to step 62 , while the priority queue Q is not empty, steps 64 through 84 are executed as appropriate. Accordingly, the method either proceeds to step 64 or to step 86 described below. Here, as the priority queue Q currently holds the starting tile S, the method proceeds on to step 64 where the lowest cost tile E is popped from the priority queue Q. To appreciate which tile is the lowest cost tile E to be popped from the priority queue Q, a brief illustration shall be necessary. Assume, for example, that the CT 118 is selected as the starting tile S and the CT 104 is selected as the destination tile T. There are seven tiles E, specifically, the tiles ST 120 , ST 124 , ST 122 , ST 114 , ST 110 , ST 200 and ST 204 , that adjoin the tile CT 118 . The distance from each tile E to the destination tile T is evaluated and the tile E closest to the destination tile T is popped from the priority queue as the lowest cost tile E. In the foregoing example, of the seven tiles E, the ST 200 is the only tile adjoining the destination tile CT 104 . Thus, as the tile ST 200 is closest to the destination tile CT 104 , the tile ST 200 is popped at step 64 as the lowest cost tile E. [0076] Proceeding on to step 66 , if the tile E popped from the priority queue is the destination tile T, steps 68 , 70 and 72 are executed. Otherwise, the method proceeds to step 74 , below. More specifically at step 68 , a tile path LP from the starting tile S to the destination tile T is retrieved from the search tree TS. At step 70 , the minimum cost C 2 from the starting tile S to the destination tile T is evaluated and, at step 72 , if the current cost C exceeds the evaluated minimum cost C 2 , then C is set to C 2 and the minimum cost point path is saved. [0077] Proceeding on to step 74 for each tile F neighboring the tile E, steps 76 through 84 are executed to expand the search tree. At step 76 , a minimum cost CF from the starting tile T to the tile F is evaluated and, at step 78 , a lower cost bound CT from the tile F to the destination tile T is evaluated. At step 80 , an estimated cost CE is set as the sum of CF and CT and, at step 82 if CE is greater than or equal to the current cost C, then the method continues and the search tree TS is pruned. Otherwise, as set forth in step 84 , the tile F is inserted into the priority queue Q with the estimated cost CE and the tile F is inserted into the tree TS as a child of the tile E. The method then proceeds to step 86 where, the saved minimum cost (if determined) is returned. Otherwise a routing failure is reported. The method then ends at step 88 . [0078] The input to the above-referenced algorithm is the list of space tiles created by the method of FIG. 3 a , a start tile S and a destination tile T. The output is the list of points for the minimum cost routing path. We maintain a priority queue Q and a search tree TS, where Q is initially set to S and S is set to the root of the search tree TS. When no point path has been found, the path cost is set to infinity. As illustrated herein, the search terminates only when the priority queue Q is empty. In every search, one tile E is popped from the priority queue Q. If the tile E is the destination tile T, then the minimum cost path from the root of the search tree to the destination tile T is evaluated and the cost compared with saved cost. An update is performed if a lower cost path is found and the corresponding path is saved. Steps 66 through 72 perform this task. Steps 74 through 84 expand the search and prune the branch. Process the neighbor tiles F of the tile E one by one. For each such tile F, CF, the minimum cost from S to F and CT, the lower bound cost to T are evaluated. The cost from S to T through this path cannot be lower than estimated CE=CF+CT. If this estimated cost is higher than the current cost C, then prune this search path; otherwise expand the search by adding tile F into tree TS as a child node of E. [0079] Thus, there has been described and illustrated herein, various methods suitable for use in conjunction with the design and manufacture of VLSI circuits. However, those skilled in the art should recognize that numerous modifications and variations may be made in the techniques disclosed herein without departing substantially from the spirit and scope thereof, which is defined solely by the claims appended hereto.

Disclosed herein is a method and associated apparatus for the design and manufacture of VLSI circuit which incorporates therein a method for routing connections between component tiles of the VLSI circuit being designed.

BACKGROUND OF THE INVENTION The present invention relates to an image reading device used in a facsimile device, copier, or the like. Conventionally, a facsimile device includes an image reading device for reading an image printed on an original. An "original" is an original document, drawing, or other sheet bearing an image to be read. The image is transmitted to another facsimile device via a modem, a network control unit (NCU), and a telephone line. A feeding device in the image reading device feeds an original, a light source illuminates the original, and an image sensor (such as a CCD) reads the reflected light. In order to provide a threshold for discriminating an image pattern from the background (usually white), the image reading device often includes a white level reference member facing the image sensor across the feed path of the originals. The white level reference member is readable when no original is present in the feed path. After the facsimile device is turned on, the image sensor reads the white surface of the white level reference member and the threshold (white level) is stored. In many facsimile devices and copiers, a movable cover is provided for covering the image reading device, and the cover can be opened for removing jammed paper. However, when the cover is not fully closed, external or ambient light may enter the interior of the facsimile device. If the external light reaches the image sensor while the image sensor is reading the white level reference member, the threshold setting may become faulty. To avoid this situation, the image reading device may incorporate a sensor (such as a limit switch) for detecting when the movable cover is fully closed. The use of such a sensor increases the cost of the device. Alternatively, the threshold can be determined at the factory and stored in an EEPROM-type memory (or other non-volatile memory). However, since the threshold data can be several hundred bytes, a relatively large EEPROM is necessary to store the threshold data, also increasing the cost. The same problem exists in a copier, an image scanner or a digitizer. SUMMARY OF THE INVENTION In order to meet this object, according to one aspect of the present invention, an image reading device includes: an image sensor for reading images from an original; a white level reference member, facing the image sensor and readable by the image sensor to set a white level threshold of the image sensor; and at least one marking formed on the white level reference member; a movable cover associated with the white level reference member; and control means for checking if the image sensor reads the at least one marking to determine a status of the movable cover based on the checking. In this manner, no special sensor is required to sense the status of the movable cover, as the marking is used to determine the status. Preferably, the control means includes means for initiating the checking in response to power being supplied to the controller. In this case, the checking is performed every time the facsimile device or other device housing the image reading device is turned on. In one particular development of this aspect of the invention, the image reading device further includes: a memory for storing the white level threshold, the control means storing the white level threshold in the memory only after the image sensor detects the marking. The white level reference member is preferably mounted to the movable cover, so that the markings are not sensed when the cover is moved away from the image sensor. The device may include display means, and wherein the controller controls the display means to indicate the status of the movable cover. According to another aspect of the present invention, an image reading device, includes: an image sensor for reading images from an original; a white level reference member, facing the image sensor and readable by the image sensor to set a white level threshold of the image sensor; and at least one marking defining a reading range of the image sensor, the at least one marking being formed on the white level reference member facing the image sensor; a movable cover associated with the white level reference member; and control means for checking if the image sensor reads the at least one marking to determine a status of the movable cover based on the checking. In this manner, no special sensor is required to sense the status of the movable cover, as the marking provided for the purpose of determining a reading range of the image sensor is used to determine the status. In one particular development, the marking or markings are a pair of parallel markings spaced by a predetermined distance on the reference surface. These marking lines are used to define the center position and width of the reading range. In another particular development, the movable cover is swingably supported to open and close. The white level reference member is swung away from the image sensor to a first position where the white level reference member is unreadable by the image sensor when the movable cover is in an open status, and to a second position where the white level reference member is readable by the image sensor when the movable cover is in a closed status. In this case, the control means preferably controls the image sensor to set the white level threshold only when the control means verifies a status of the movable cover to be a closed status where the white level reference member is readable by the image sensor. In still another aspect of the invention, an image reading device includes: a lower guide plate having an opening formed therein; an upper member, swingable toward and away from the lower guide plate; a line image sensor attached to the lower guide plate, the line image sensor positioned to read images through the opening; a white level reference member attached to the upper member in a position readable by the line image sensor only when the white level reference member is swung toward the lower guide plate, the white level reference member defining a white level threshold of the image sensor when the image sensor reads the white level reference member; a pair of markings on the white level reference member in a position readable by the line image sensor only when the white level reference member is swung toward the lower guide plate, the pair of markings being separated from each other by a predetermined distance; and a controller includes: means for checking a position of the upper member based on a reading of the pair of markings by the line image sensor, means for setting a reading range of the line image sensor based on a reading of the predetermined distance from the pair of markings by the line image sensor; and means for setting a white level threshold of the image sensor based on a reading of the white level reference member by the line image sensor. In this manner, the controller carries out three functions based upon the reading of the reference surface: setting of reading range, setting of white level threshold, and checking the upper member position. Since the upper member is preferably provided to a swingable cover, the controller determines the position of the swingable cover depending on the means for checking a position of the upper member. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a facsimile device employing an embodiment of an image reading device according to the invention; FIG. 2 is a schematic side view of the facsimile of FIG. 1; FIG. 3 is a perspective view of an original reading portion of the facsimile device of FIG. 1; FIG. 4 is a schematic bottom view of a white level reference member of the original reading portion of FIG. 3; FIG. 5 is a block diagram of a control system of the image reading device; and FIG. 6 is a flow chart showing an initializing operation of the image reading device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a perspective view of a facsimile device 1 to which the embodiment of the invention is applied, and FIG. 2 is a schematic side view of the facsimile device 1. As shown in FIG. 1, the body of the facsimile device includes a lower cover 2 and an upper cover 3. A handset 4 is provided at one side of the lower cover 2. A recording sheet cassette 6 is attachable to and detachable from the lower case 2. An original holder 18 accepts originals to be read. A movable cover 19, having an operation panel 42 with a display 42a, is rotatably supported on the upper cover 3. As shown in FIG. 2, a number of recording sheets 5 are stacked in the recording sheet cassette 6. A single recording sheet 5 is fed by a sheet feeding roller 7 from the stack to a pair of intermediate feeding rollers 8, which feed the sheet 5 to a printing unit 11 including a thermal line printing head 9 and a platen roller 10. When the recording sheet 5 reaches the printing unit 11, the intermediate feeding rollers 8 wait until the facsimile device 1 receives image data from another facsimile device, and then feed the recording sheet 5 in tandem with the platen roller 10. When the facsimile device 1 receives the image data, the image is reproduced on the waiting recording paper 5 via an ink sheet 14 (fed from a feeding reel 12 and wound by a winding reel 13). The recording sheet 5 on which the image is formed is discharged through a recording sheet discharge slot 16 by a pair of discharge rollers 15. One or more originals 17 are placed on the original holder 18, inclined downward to the front side of the facsimile device 1. The movable cover 19 is swingably supported about a shaft 19a provided to the front side of the upper cover 3. The original 17 placed on the original holder 18 is fed by a separating roller 20 (if more than one original, it is separated from the remaining originals) and a pair of feeding rollers 21 through an original reading portion and discharged through an original discharge slot 24. The original reading portion is shown in detail in FIGS. 3 and 4. As shown in FIG. 3, the original 17 is fed between an upper guide plate 27 and a lower guide plate 26 in the original reading portion to a CCD scanner 22. The CCD scanner 22 is provided to the lower guide plate 26. The lower guide plate 26 has an opening (elongated in the direction of original width) through which a detecting surface of the CCD scanner 22 can face the upper guide plate 27. The original reading portion includes an original detecting switch 25 provided upstream of the CCD scanner 22 for reading an image. The original detecting sensor 25 can be a contact type sensor, such as a micro limit switch, or a non-contact type sensor, such as a photosensor. The original detecting sensor 25 is provided upstream of the CCD scanner 22 by a distance L 1 . A white level reference member 28 having the same length as the detecting surface of the CCD scanner 22 is attached to the upper guide plate 27. As shown in FIG. 4, a pair of black lines 28a, 28a are formed having an interval H1 in the width direction of the original 17 (i.e., the scanning direction of the CCD 22). The interval H1 is provided for setting the reading range of the original in the direction of the original width. That is, a CPU 30 (described later) sets the center position of the reading range according to the center position of the black lines 28a--28a as readby the CCD 22. FIG. 5 is a block diagram showing a control system 29 of the facsimile device. A CPU 30 is connected (via a bus 37) to a power switch 34, a ROM 31 storing a control program, a readable and writable non-volatile memory (EEPROM) 32, a RAM 33, the CCD scanner 22, the original detecting sensor 25, the printing unit 11, and driving circuit 36 for driving a stepping motor 35 which drives the feeding rollers 21. The EEPROM 32 has a quick-dial number storing area, an originator's number storing area, a communication condition storing area, and a function storing area (including communication mode, program and function data). The RAM 33 has a communication managing information storing area for storing communication information such as the date and time of a communication. The CPU 30 is also connected by the bus 37 (via unillustrated connections) to the operation panel 42 for entering data such a facsimile number, the LCD display 42a of the operation panel 42, and the handset 4. The CPU is further connected to unillustrated elements well known in the art: a network control unit (NCU) for controlling a network via an external telephone exchange, a modem, a buffer memory for temporarily storing the coded image data, a coding circuit for coding the image data to be transmitted, a decoding circuit for decoding the image data received, and an image memory for storing the received data a clock circuit for a calendar function such as date and time, and a character generating portion for displaying characters on the LCD display 42a and for generating characters according to the character code for printing by the printing unit 11. An initializing operation of the facsimile device 1 is shown in the flowchart of FIG. 6. As shown in FIG. 6, when the power switch 34 is turned ON (step S1), the CCD scanner 22 is driven and begins scanning in step S2. In step S3, the CPU 30 evaluates the result of the CCD scan, and checks if the black lines 28a, 28a on the white level reference member 28 can be recognized in the line image data at step S3. If the CPU 30 does not recognize the black lines 28a, 28a in the line image data (N at step S3), the CPU 30 illuminates an LED lamp (not shown) provided on the operation panel 42, displays "COVER OPEN" in the LCD display 42a, then returns to step S2. That is, the CPU 30 recognizes that the cover is open if the black lines 28a, 28a, are not detected. If the CPU 30 recognizes the black lines 28a, 28a in the line image data (Y at step S3), it proceeds to step S5. In step S5, "COVER OPEN" in the display is erased. Naturally, if "COVER OPEN" was never displayed, step S5 has no effect. The CPU 30 will only proceed to step S5 if the cover 19 is sufficiently, i.e., completely, closed. The process then proceeds to step S6. In step S6, the CPU 30 reads the white reference surface, and continues to step S7, where the threshold data from reading the white level reference member 28 is stored in the RAM 33. In this manner, when the facsimile device 1 is turned on, the CPU 20 uses the image signal from the CCD 22 to detect whether or not the cover 19 is fully closed. Consequently, the facsimile device 1 does not need an independent sensor for detecting whether the cover 19 is fully closed or not. Furthermore, the threshold is renewed every time the facsimile device is turned on, and a large EEPROM or other non-volatile memory for storing threshold data is not needed. Furthermore, by fixing the upper guide plate 27 to the cover 19, the gap between the guide plates 26 and 27 becomes larger when the cover 19 is opened. Therefore, the operation for removing the original may become easier. Still further, by providing the white level reference member 28 to the surface of the upper guide plate 27, the operation for cleaning or replacement of the white level reference member 28 may be easier. The present disclosure relates to subject matter contained in Japanese Patent Application No. HEI 07-135110, filed on Jun. 1, 1995, which is expressly incorporated hereinby reference in its entirety.

A reference surface for determining a threshold level of an image sensor is provided on a guide plate swingable with a cover away from the image sensor. The reference surface has markings thereon for determining a reading range of the image sensor. The image reading device makes three detections from the reading of the reference surface: a detection of the cover position by detecting the presence of the markings; a detection of the reading range of the image sensor by detecting the arrangement of the markings; and a detection of the threshold level of the image sensor by detecting the background of the reference surface. The threshold level is not taken until the device has determined that the cover is closed.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to input devices for computers and, in particular, to devices, systems and methods for facilitating positioning of a cursor on a display device of a computer-based system. 2. Description of the Related Art With the use of large and multi-head display devices becoming ever more prevalent, computer operators, such as graphic and CAD designers, for example, are experiencing difficulties interfacing with computer applications displayed on the display devices when utilizing conventional mouse-type input devices. More specifically, computer operators are finding it difficult to utilize the increased display area provided by the larger and multi-head displays without experiencing a characteristic of cursor movement about the display known as “mouse twitch” or “jump.” As utilized herein, “twitch” or “jump” is defined as the tendency of a mouse-driven cursor to move in a manner not desired by the operator. For instance, twitch may occur when the operator attempts to actuate a function of a mouse-type input device, such as by depressing an actuator or button of the mouse. Movement of the cursor during an actuation of a mouse function may occur when the cursor is in a location on the display device that is not designated by one of a predetermined number of grid points. For instance, when the cursor is located at a non-grid point and a mouse function is actuated, typically, the cursor will tend to move, i.e., twitch or jump, to the grid point closest to the cursor's current location. Movement of the cursor during an actuation of a mouse function also may occur due to inadvertent movement of the mouse during such actuation. Additionally, when an operator utilizes large or multi-head display devices, typically, the operator selects speed/sensitivity settings for the mouse that allow a small movement of the mouse to correspond to a relatively large movement of the associated cursor across the display area(s). However, many operations, such as CAD operations, oftentimes require the use of precise (small) cursor movements which are not easily accommodated by the aforementioned operator-selected speed/sensitivity settings of the mouse. Heretofore, in an effort to avoid mouse twitch or jump, computer operators typically change mouse speed and/or sensitivity settings for a mouse-type input device when switching between various computer applications and/or displays. Thus, it is not uncommon for a computer operator to switch mouse speed and/or sensitivity settings when switching from applications such as word processing, or other text-based applications, for example, to a graphic-based application, such as CAD, for instance, or even from one CAD function to another. However, since each change of mouse speed and/or sensitivity settings takes time, the efficiency of the computer operator may be reduced in proportion to the number of changes made. Therefore, there is a need for improved devices, systems and methods which address these and other shortcomings of the prior art. SUMMARY OF THE INVENTION Briefly described, the present invention relates to input devices for computers and, in particular, to devices, systems and methods for facilitating positioning of a cursor on a display device of a computer-based system. Such a computer-based system is adapted to facilitate operation of a computer application which is adapted to display a cursor within a display area of a display device of a computer. Typically, the computer includes a mouse-type input device for providing movement information and functional information corresponding to the cursor so that the cursor is movable about the display area in response to the movement information and is adapted to provide selected functionality in response to the functional information. In a preferred embodiment of the present invention, an input device is provided which includes a shifter configured to electrically communicate with the computer. The shifter is configured to enable functional information, provided by the mouse-type input device, to provide selected functionality of the cursor. The shifter also provides a shift-disable mode and a shift-enable mode so that, while in the shift-disable mode, the shifter enables the mouse-type input device to influence movement of the cursor on the display device. For instance, a movement of the mouse-type input device in a first direction and a first distance results in the cursor moving the first direction and a corresponding second distance. In the shift-enable mode, the shifter enables an altering of movement of the cursor so that movement of the mouse-type input device in the first direction and the first distance results in the cursor moving the first direction and a corresponding third distance, with the third distance being unequal to the second distance. In another embodiment, an input device is provided for interfacing with a computer application. Preferably, the input device includes: means for enabling functional information, provided by the mouse-type input device, to provide selected functionality of the cursor: means for enabling the mouse-type input device to influence movement of the cursor on the display device so that a movement of the mouse-type input device in a first direction and a first distance results in the cursor moving a corresponding second direction and second distance; and means for enabling an altering of movement of the cursor so that movement of the mouse-type input device in the first direction and the first distance results in the cursor moving the second direction and a corresponding third distance, with the third distance being unequal to the second distance. In another embodiment, a computer system for operating a computer application is provided. Preferably, the computer system includes a display device, a mouse-type input device and a shifter. In still another embodiment, a computer readable medium incorporating a computer program for interfacing with a computer application is provided. Preferably, the computer readable medium includes: logic configured to enable movement information, provided by the mouse-type input device, to influence movement of the cursor on the display device so that a movement of the mouse-type input device in a first direction and a first distance results in the cursor moving a corresponding second direction and second distance; logic configured to enable functional information, provided by the mouse-type input device, to provide selected functionality of the cursor; and logic configured to enable an altering of movement of the cursor so that movement of the mouse-type input device in the first direction and the first distance results in the cursor moving the second direction and a corresponding third distance, with the third distance being unequal to the second distance. Embodiments of the present invention also may be construed as providing methods for interfacing with a computer application. In a preferred embodiment, a method for interfacing with a computer application includes the steps of: enabling movement information provided by the mouse-type input device to influence movement of the cursor on the display device so that a movement of the mouse-type input device in a first direction and a first distance results in the cursor moving a corresponding second direction and second distance; enabling functional information, provided by the mouse-type input device, to provide selected functionality of the cursor; and enabling an altering of movement of the cursor so that movement of the mouse-type input device in the first direction and the first distance results in the cursor moving the second direction and a corresponding third distance, with the third distance being unequal to the second distance. Other features and advantages of the present invention will become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such features and advantages be included herein within the scope of the present invention, as defined in the appended claims. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS The present invention, as defined in the claims, can be better understood with reference to the following drawings. The drawings are not necessarily to scale, emphasis instead being placed on clearly illustrating the principles of the present invention. FIG. 1 is a diagram depicting mouse twitch or jump. FIG. 2 is a schematic diagram depicting a processor-based system which may be utilized in implementing a preferred embodiment of the preferred invention. FIG. 3 is a high-level block diagram depicting a preferred method of the present invention. FIG. 4A is a schematic diagram depicting an embodiment of the present invention. FIG. 4B is a schematic diagram depicting an embodiment of the present invention. FIG. 5 is a schematic diagram depicting an embodiment of the present invention. FIG. 6 is a schematic diagram depicting an embodiment of the present invention. FIG. 7 is a schematic diagram depicting an embodiment of the present invention. FIG. 8 is a diagram depicting representative cursor movement facilitated by a preferred embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Reference will now be made in detail to the description of the invention as illustrated in the drawings with like numerals indicating like parts throughout the several views. As is known, a display device, e.g., a computer monitor, is configured for displaying graphical information provided by a processor-based system. For instance, a display device may be configured for presenting a computer application, such as a CAD application, to an operator. A representative depiction of a CAD application, as typically displayed on a display device, is shown in FIG. 1 . It should be noted that the preferred embodiments of the present invention described herein will be discussed, primarily, in relation to a CAD application, such as the application depicted in FIG. 1, for ease of description and not for purposes of limitation. Thus, the present invention may be utilized with numerous other applications incorporating the use of a mouse-driven cursor, as described in detail hereinafter, with such other applications being considered well within the scope of the present invention. As depicted in FIG. 1, CAD application 12 provides a computer operator with a grid network 14 formed of a series of horizontal rows 16 and a series of vertical columns 18 , with the grid network, oftentimes, being displayed to the operator. A plurality of predetermined points 20 are established at the intersections of the rows and columns, thereby providing the operator with grid-established points at which a cursor, such as cursor 22 , may be located when performing various functions provided by the application. The computer operator typically interfaces with the application by manipulating a mouse-type input device (not shown) that provides x and y coordinate data, corresponding to the movements of the mouse-type input device, as well as function-actuation data, corresponding to actuation of a “left-click” or “right-click” button, for example, to the processor-based system. The processor-based system then evaluates the various data and displays an appropriately positioned cursor 22 on the display. Thus, by moving the mouse-type input device and/or by actuating various actuators of the device, the computer operator may enable various application functionality at various locations about the display. As mentioned briefly hereinbefore, a cursor may present the operator with mouse twitch or jump. For instance, when the cursor 22 is displayed in position A (FIG. 1 ), which is defined by a point 20 of the grid network, and an actuator of the mouse-type input device is depressed or the mouse-type input device is inadvertently moved, the cursor may move without additional operator input to position B, which also is defined by a point 20 of the grid network. Thus, a zone 24 surrounds position B, whereby actuation of a mouse function while the cursor is displayed within the zone 24 results in the cursor moving to the center of that zone, e.g., the point 20 of the grid network. Likewise, a zone 26 surrounds position D, whereby actuation of a mouse function while the cursor is displayed within the zone 26 , such as when the cursor is being displayed at position C, results in the cursor moving to the center of zone 26 . If the computer operator desires to have the particular mouse functionality enabled at the location A, and not at position B which occupies the center of zone 24 , the operator typically must reset the mouse speed and/or sensitivity settings to an appropriate setting so that the position A may be appropriately and/or more conveniently recognized. As described in detail hereinafter, the present invention provides devices, systems and methods for repositioning the cursor (such as to position A) which, otherwise, typically is positioned by utilizing a mouse-type input device. As mentioned briefly hereinbefore, cursor movement may be facilitated by the present invention which, hereinafter, may be referred to as “the shifter,” “shifter system” and/or “method.” The shifter system of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In a preferred embodiment, however, the shifter system is implemented as a software package, which can be adaptable to run on different platforms and operating systems as shall be described further herein. In particular, a preferred embodiment of the shifter system, which comprises an ordered listing of executable instructions for implementing logical functions, can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device, and execute the instructions. In the context of this document, a “computer-readable medium” can be any means that can contain, store, communicate, propagate or transport the program for use by or in connection with the instruction execution system, apparatus, or device. The computer readable medium can be, for example, but not limited to, an electronic, magnetic, optical, electro-magnetic, infrared, or semi-conductor system, apparatus, device, or propagation medium. More specific examples (a nonexhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic) having one or more wires, a portable computer diskette (magnetic), a random access memory (RAM) (magnetic), a read-only memory (ROM) (magnetic), an erasable, programmable, read-only memory (EPROM or Flash memory) (magnetic), an optical fiber (optical), and a portable compact disk read-only memory (CDROM) (optical). Note that the computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via for instance, optical scanning of the paper or other medium, then compiled, interpreted, or otherwise processed in a suitable manner, if necessary, and then stored in a computer memory. FIG. 2 illustrates a typical computer or processor-based system 200 which may utilize the shifter system 100 of the present invention. As shown in FIG. 2, a computer system 200 generally comprises a processor 202 and a memory 204 with an operating system 206 . Herein, the memory 204 may be any combination of volatile and nonvolatile memory elements, such as random access memory or read only memory. The processor 202 accepts instructions and data from memory 204 over a local interface 208 , such as a bus(es). The system also includes an input device(s) 210 and an output device(s) 212 . Examples of input devices may include, but are not limited to a serial port, a scanner, or a local access network connection. Examples of output devices may include, but are not limited to, a video display, a Universal Serial Bus, or a printer port. Generally, this system may run any of a number of different platforms and operating systems, including, but not limited to, Windows NT™, Unix™, or Sun Solaris™ operating systems. The shifter system 100 of the present invention, the functions of which shall be described hereinafter, resides in memory 204 and is executed by the processor 202 . The flowchart of FIG. 3 shows the functionality and operation of a preferred implementation of the shifter system 100 depicted in FIG. 2 . In this regard, each block of the flow chart represents a module segment or portion of code which comprises one or more executable instructions for implementing the specified logical function or functions. It should also be noted that in some alternative implementations, the functions noted in the various blocks may occur out of the order depicted in FIG. 3 . For example, two blocks shown in succession in FIG. 3 may in fact be executed substantially concurrently where the blocks may sometimes be executed in the reverse order depending upon the functionality involved. As depicted in FIG. 3, the process preferably begins at block 302 where a determination is made as to where the shifter is enabled. If it is determined that the shifter is not enabled, the process preferably proceeds to block 304 where cursor speed/sensitivity defaults are facilitated. If, however, it is determined that shifter has been enabled, the process preferably proceeds to block 306 where mouse input, such as movement information and function information, for example, is received. At block 308 speed/sensitivity-modification input is received and then, such is depicted at block 310 , cursor speed/sensitivity is modified in a manner corresponding to the modification inputs received. After appropriate modification, the process preferably proceeds to block 312 , where a determination is made as to whether the shifter has been disabled. If it is determined that the shifter has not been disabled, the process preferably proceeds back to block 306 and then continues as described hereinbefore. If, however, it is determined that the shifter has been disabled, the process preferably returns to block 304 where a default cursor speed and sensitivity settings are once again facilitated. Thereafter, the process may return to block 302 and then proceed as described hereinbefore. Thus, alternating between the aforementioned enabled and disabled modes of the shifter allows an operator to conveniently alter the speed/sensitivity settings of the cursor between pre-established default settings and operator-modified settings. As depicted in FIG. 4A, a preferred embodiment 400 of the present invention incorporates the use of a shifter device 410 . Shifter device 410 is electrically interconnected intermediate of a mouse-type input device 412 and its associated computer system 414 , and preferably incorporates the use of one or more components or actuators (not shown) for “shifting” the device between the default and operator-modified cursor settings. Regardless of the particular configured utilized, the shifter device facilitates modification of cursor speed/sensitivity settings, thereby allowing a mouse-type input device to provide a more operator-friendly interface device. As depicted in FIG. 4B, an alternative embodiment 450 can use a keyboard to implement shifter functionality. In particular, keyboard 460 may utilize a user-specified key, e.g., key 470 , which has been remapped as a shifter enable key. Thus, after the keyboard has been remapped, actuation of the shifter enable key enables cursor speed/sensitivity settings to be shifted between default and operator-modified cursor settings. Referring now to FIG. 5, an alternative embodiment 500 also incorporates the use of a shifter device 510 . In contrast to the embodiment depicted in FIG. 4, however, system 500 incorporates the use of such a shifter device in a non-in-line arrangement. In particular, the shifter device 510 is configured to provide shifter data to the computer 514 via an interface device or switch box 516 which also is configured to receive input from the mouse-type input device 518 . So configured, the switch box facilitates interception and/or modification of movement information provided by the mouse-type input device, such as when a shifter-enable switch of the shifter device is actuated, for instance. Functional information provided by the mouse-type input device, however, is routed through the switch box and to the computer to facilitate various functionality provided by the mouse-type input device. Referring now to FIG. 6, an alternative embodiment 600 incorporates the use of a shifter device 610 which is configured to provide shifter data directly to a computer 614 . Preferably, the computer also is adapted to receive input from the mouse-type input device 616 . So configured, the movement information provided by the mouse-type input device may be modified by the computer in response to data received from the shifter, thereby allowing the shifter device to influence cursor location and movement, while functional information provided by the mouse-type input device continues to provide various mouse functionality. Such a configuration may be implemented by use of a software application, such as the application described in relation to FIG. 3, for instance. A preferred embodiment of an shifter device 700 of the present invention is depicted in FIG. 7 . As shown therein, shifter device includes a body 710 , primary actuators 712 and 714 , and a secondary actuator 716 . Preferably, actuators 712 and 714 are configured for providing conventional mouse functionality, such as “left-click” and “right-click” functions, respectively, and secondary actuator 716 provides shifter functionality, as described in detail hereinbefore. The actuators may be provided in numerous configurations and arrangements in order to fulfill their respective intended functions. It also should be noted that shifter device 700 is capable of providing cursor movement data to a computer in one of various conventional manners. Referring now to FIG. 8, the movement of a cursor, such as from location A to B1 (or C1) typically is facilitated by a corresponding movement, i.e., a movement characterized by a direction and a distance, of a mouse-type input device, e.g., device 700 being moved from A to B (or A to C). The shifter of the present invention may interface with a computer so that the same movement of the mouse-type input device allows the cursor to be moved to a different location on the display device. For instance, as depicted in FIG. 8, the shifter may allow the cursor to be moved from position A to B2 (or C2), with the same movement of the mouse-type input device described hereinbefore in relation to B1 and C1, respectively. When utilizing a shifter device, such as the shifter device 700 (FIG. 7 ), to facilitate the aforementioned cursor movements, the speed/sensitivity setting may be conveniently changed by actuating shifter-enable switch 716 by a simple movement of the thumb. The present invention accommodates numerous setting/sensitivity schemes, such as a single-click scheme, whereby a single, modified setting may be actuated by actuating a shift-enable switch, and a multi-click scheme, whereby multiple settings may be actuated by actuating a shift-enable switch an appropriate number of times, among others. The foregoing description has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiment or embodiments discussed, however, were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations, are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly and legally entitled.

Devices, systems and methods for facilitating positioning of a cursor on a display device are provided. For example, an input device is provided which includes a shifter configured to electrically communicate with a computer. The shifter is configured to enable functional information, provided by a mouse-type input device, to provide selected functionality of the cursor. The shifter provides a shift-disable mode and a shift-enable mode so that, while in the shift-disable mode, the shifter enables the mouse-type input device to influence movement of the cursor on the display device. For instance, a movement of the mouse-type input device in a first direction and a first distance results in the cursor moving the first direction and a corresponding second distance. In the shift-enable mode, the shifter enables an altering of movement of the cursor so that movement of the mouse-type input device in the first direction and the first distance results in the cursor moving the first direction and a corresponding third distance, with the third distance being unequal to the second distance.

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The invention relates to a device and method that enables Internet communication products to receive and send electronic voice mail, and more particularly, to a device and method that enables the sending and receiving of voice mail through the Internet, by means of a PDA, PC, notebook computer, or hand-held PC, for example. [0003] 2. Related Art [0004] Because of the rapid development of mobile phone industry and the promotion by the mobile communication service industry, cellular phone has been so popular that it is almost owned by everybody; utility model of cellular phone not only transmits each speaker's voice, but also possesses multimedia functions necessary for the new generation of cellular phone. Telecommunication suppliers not only provide the most basic 2-way voice transmission service, but also provide functions such as message, Web surfing, and even voice mailbox that frees both the receiver and the sender who fail to communicate with each other by voice instantly from the complicated process of keying in the text of a message to be sent. [0005] The voice mailbox usually carries out the recording, playing and storage of sounds by means of a telecommunication network and an ordinary voice telephone. For instance, under a mobile communication service system (e.g. GSM system), a sender can leave a voice message in a voice mailbox provided by a telecommunication supplier. However, the user has to pay an additional charge for using the voice mailbox. With an ordinary voice telephone system, a voice message can be left on a digital answering machine. [0006] Given the rapid development of Internet, Internet communication products such as PDA, PC, notebook or hand-held PC, which possess the function of Web linkage, but not the functions of cellular phone, have been popularized to a great extent. Although many Internet communication products nowadays can use built-in modem chip to receive and send email or browse Web page, most of them can only receive and send simple text files. As regards to PC, it possesses the most complete functions, enabling a user to receive and send, at the user's own choice, all kinds of multimedia messages or files, such as a voice document, to allow a friend at the receiver end to listen to a sender's greetings. Although all the other Internet communication products are equipped with modems (or modem chips) that have sound recording and playing functions, so far there has not been any known technology through which the functions of voice mailbox are enabled. SUMMARY OF THE INVENTION [0007] The primary object of the invention is to provide a device and method that enables Internet communication products to have the function of a voice mailbox. [0008] The method revealed by the present invention is aimed at, and designed for, those Internet communication products that merely possess Web linkage function, but do not have the functions of ordinary voice telephone. For instance, all PDA or hand-held PC that possesses Web linkage function may enable the function of voice mailbox through the technology of the present invention. [0009] The technology employed by the invention involves a voice message being picked up by a microphone of an Internet communication product. The voice message is then recorded by means of the sound recording function of the Internet communication product, resulting in the creation of a voice file. After that, a recipient's information and voice file are turned into a voice message packet that is then sent to a Web server via the Internet for storage. After connecting with the Web server via the Internet, the recipient may download from the Web server a corresponding voice message packet, which will be available to the recipient's Internet communication product. Eventually, the voice message is played by means of the voice playing function of the Internet communication product, so that the functions of a voice mailbox will be attained. [0010] The description of the detailed technology and embodiment of the present invention is made with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0011] The invention will become more fully understood from the detailed description given herein below. However, this description is for purposes of illustration only, and thus is not limitative of the invention, wherein: [0012] [0012]FIG. 1 is a diagram showing the systemic structure for the implementation of the invention. [0013] [0013]FIG. 2 shows the basic structure of Internet communication products. [0014] [0014]FIG. 3 is a diagram showing the structure of another embodiment of Internet communication products. [0015] [0015]FIG. 4 is the flowchart about the main steps of the method for the present invention. [0016] [0016]FIG. 5 is the flowchart about the embodiment for creating a voice message packet. [0017] [0017]FIG. 6 is the flowchart about the embodiment for sending a voice message packet. [0018] [0018]FIG. 7 is the flowchart about the embodiment for receiver's downloading a voice message packet. [0019] [0019]FIG. 8 is the flowchart about the embodiment for playing a voice message packet. [0020] [0020] 10a, 10b Internet communication products 11 Internet connection port 12 microphone 13 speaker 14 modem chip 15 microprocessor unit 151  Internet communication program 152  sound recording program 153  sound playing program 16 input unit 17 display unit 18 register 20 Web server DETAILED DESCRIPTION OF THE INVENTION [0021] First of all, see FIG. 1, which is a diagram showing the systemic structure of the present invention, comprising the following components that are linked together via Internet: [0022] A local Internet communication product 10 a that has the functions of sound recording and playing, and Internet linkage. This is the sender, and it produces a voice message packet; [0023] A Web server 20 , which is linked to Internet communication product 10 a by Internet, in order to allow the Internet communication product 10 a to upload and download voice message packets; and [0024] A remote Internet communication product 10 b that also has the functions of sound recording and playing, and Internet linkage. This is the recipient. After being linked to the Web server 20 over the Internet, it downloads the voice message packets stored in the Web server 20 , and it eventually plays the voice messages contained in the voice message packets. [0025] The foregoing Internet communication product 10 a, 10 b can either be a PDA, or a hand-held PC, equipped with the function of Web linkage. The basic structure of such an Internet communication product, as depicted in FIG. 2, comprises: [0026] An Internet connection port 11 , such as an RJ11 connector, for connecting to the Internet and thus creating an Internet communication path; [0027] A microphone 12 for picking up a user's message and converting it into an electrical signal; [0028] A speaker 13 for playing a voice message downloaded from the Internet; [0029] A modem chip 14 for linking to the Internet so as to facilitate the transmission and receipt of data; [0030] A register 18 for storing the data of a voice message by means of either RAM or flash memory; [0031] A microprocessor unit 15 , which comprises a built-in Internet communication program 151 , a built-in sound recording program 152 and a built-in sound-playing program 153 . The built-in Internet communication program 151 , when executed, enables the modem chip 14 to upload or download data via Internet. The built-in sound recording program 152 enables the modem chip 14 to start converting a voice message picked up by the microphone 12 into a voice file, and then storing the voice file in the register 18 . The built-in sound playing program 153 enables the modem chip 14 to start disassembling the voice message packets downloaded from the Web server 20 , and then playing the voice message through the speaker 13 ; and [0032] An input unit 16 , for example, a touch screen, keyboard, or both, that allows users to control the Internet communication product 10 a or 10 b in sending or receiving voice messages. [0033] Of course, the aforesaid Internet communication product 10 a , 10 b can also comprise a display unit 17 (see FIG. 3), for example a touch screen, a LCD or an indicator light. Such a display unit 17 is controlled by the microprocessor unit 15 , and its purpose is to display a prompt message so as to instruct a user to carry out the operation of the sound recording or the receipt of a voice message. [0034] Please continue to FIG. 4, which is a flow chart of the main steps of the method of the invention. It comprises: [0035] 1. The step of creating a voice message packet. It uses the sound recording function of the Internet communication products 10 a to turn sender's voice message and receiver's information (such as receiver's identification data or email address) into a voice message packet; [0036] 2. The step of sending a voice message packet. It uses the Internet communication function of the Internet communication product 10 a to send a voice message packet to a Web server 20 ; [0037] 3. The step of downloading a voice message packet. Receiver uses the Internet communication function of the Internet communication product 10 b to link up itself with a Web server 20 through Internet, and from the Web server 20 it downloads corresponding voice message packets to receiver's Internet communication product 10 b; and [0038] 4. The step of playing a voice message packet. It uses the sound playing function of the recipient's Internet communication product 10 b to disassemble and play the downloaded voice message packet. [0039] As shown in FIG. 5, the detailed procedures of the foregoing creation of a voice message packet are as follows: 1-1 Begin. It starts after a user has given a sound recording command through an input unit 16; 1-2 Start and initialize a modem chip 14. In other words, it starts the modem chip 14, and sends an initialization command to keep the modem chip 14 in a preparation status; 1-3 Set the modem chip 14 to the voice mode, for example, a micro- processor unit 15 sends a modem chip 14 a command, “AT#CLS = 8”; 1-4 Start the connection mode of microphone 12 and modem chip 14, for example, a microprocessor unit 15 sends a modem chip 14 a command, “AT# VLS = 3”; 1-5 Cause a display unit 17 to display a prompt message for starting sound recording (for example, a text message or a glittering light); 1-6 Start a sound recording program, and cause the modem chip 14 to convert the voice message picked up by the microphone 12 into a voice file that will then be stored in a register 18. For example, a microprocessor unit 15 sends a modem chip 14 a command, “AT# VRX”; 1-7 Create a voice message packet. Turn the sender's information (such as the recipient's identification data or email address) and voice file into a voice message packet and store the voice message packet in the register 18; and 1-8 End the generation of the voice message packet. [0040] As shown in FIG. 6, detailed embodiment procedures of sending a voice message packet are as follows: 2-1 Begin. It starts after a user has given a command through an input unit 16; 2-2 Connect with Internet; start a modem chip 14 so as to connect with Internet; 2-3 Connect with a Web server 20; 2-4 Upload a voice message packet to the Web server 20; and 2-5 End Internet connection. [0041] As shown in FIG. 7, the detailed procedures of the recipient downloading a voice message packet are as follows: 3-1 Begin. It starts after a user has given a command through an input unit 16; 3-2 Connect to the Internet; start a modem chip 14 so as to connect to the Internet; 3-3 Connect to a Web server 20; 3-4 Look for a voice message packet stored in the Web server 20; according to the default recipient's information-the search condition, go to the next step whenever a corresponding voice message packet is found, otherwise end the Internet connection; 3-5 Download the voice message packet stored in the Web server 20 and store it in a register 18; 3-6 Delete the voice message packet stored in the Web server 20; and 3-7 End the Internet connection. [0042] Of course, in the aforesaid steps 3-5, the identity of the recipients who download voice message packets can be scanned by means of identification and inspection, or through a safety procedure of encryption/decryption, so that only those recipients who pass the identification and inspection of identity can be allowed to download voice message packets. [0043] Finally, as shown in FIG. 8, detailed procedures about playing a voice message packet are as follows: 4-1 Begin. It starts after a user has given a playing command through an input unit 16; 4-2 Start and initialize a modem chip 14. In other words, it starts the modem chip 14, and sends an initialization command to keep the modem chip 14 in a preparation status; 4-3 Set the modem chip 14 to the voice mode, for example, a micro- processor unit 15 sends a modem chip 14 a command, “AT#CLS = 8”; 4-4 Start the connection mode of speaker 13 and modem chip 14, for example, a microprocessor unit 15 sends a modem chip 14 a command, “AT# VLS = 2”; 4-5 Cause a display unit 17 to display a prompt message about starting to play a voice message (for example, a text message or a glittering light); 4-6 Start a sound playing program, and cause the modem chip 14 to disassemble a voice message packet, that is, cause the modem chip 14 to disassemble the voice message packet downloaded from a Web server 20, and then play the voice message through speaker 13. For example, a microprocessor unit 15 sends a modem chip 14 a command, “AT# VTX”; and 4-7 End playing voice message. EFFECT OF THE INVENTION [0044] Making good use of the functions of sound recording, sound playing and Internet communication of Internet communication products, coupled with the Web servers of Internet, provide paths for receiving and sending voice messages as well as places for storing voice messages, so that Internet communication products that possess the function of Web linkage, but not the function of ordinary voice telephone, can gain access to the service of voice mailbox. [0045] Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

A device and method that enables Internet communication products equipped with Web linkage functions to have the functions of a voice mailbox available only in general telecommunication systems or voice telephones through the multimedia service of the Internet. The invention uses the sound recording, playing functions and Internet communication of Internet communication products to turn voice data recorded and receiver's data into a voice message packet which is then sent to a Web server for storage, so that voice message can be retrieved from the voice mailbox when receiver's Internet communication products are linked to the Web server by Internet, to receive and send voice mail as well as use the voice mailbox.

TECHNICAL FIELD [0001] The present invention relates to a process for preparing a masterbatch comprising sulfur, more generally comprising a sulfur-based material, and carbon-based nanofillers, and also the masterbatch obtained in this way and the various uses thereof. Another subject of the invention is a solid composition comprising carbon-based nanofillers dispersed in a sulfur-based material. PRIOR ART [0002] Sulfur is very widely and commonly used in very numerous fields of industry, especially the chemical industry as synthesis reagent for the preparation of various chemical compounds, such as, for example, sulfuric acid, sulfur dioxide, oleums, carbon disulfide, sulfites or sulfates for the paper industry, or phosphorus pentasulfides as lubricant. [0003] Sulfur is also used as elemental sulfur of formula Ss, for the vulcanization of tires, as fungicide in agriculture, or as sulfur polymers for cement and concrete, or as heat transfer or storage fluid, especially for power stations (thermal or nuclear) or for solar panels, and also as active material for Li/S battery electrodes. [0004] An important raw material for elemental sulfur is hydrogen sulfide, recovered during the exploitation of natural gas deposits or by desulfurization of crude petroleum. Since reserves of natural gas tend to run out, elemental sulfur may be extracted directly by drilling into the Earth's crust, since sulfur is a relatively abundant nonmetallic element (only 0.06% of the Earth's crust, but readily extractable) and is non-toxic. [0005] The availability of the raw material makes it possible to envisage the large-scale and long-term development of uses of sulfur, in elemental form or in the form of sulfur-based material, in numerous fields of application. [0006] In some of these applications it may be advantageous to add carbon-based nanofillers such as carbon nanotubes (CNT) to the use of sulfur, in order to provide properties of electrical conductivity and/or mechanical properties. For example, it is envisaged to introduce carbon nanotubes to thermosetting elastomers before their vulcanization in order to produce reinforced tires, or else it is envisaged to add carbon nanotubes into formulations of electrodes for lithium-sulfur batteries in order to improve the kinetics of the electrochemical reactions involved. [0007] However, it has never been envisaged to directly introduce carbon nanotubes into sulfur, especially because CNTs prove difficult to handle and disperse because of their small size, their pulverulence and potentially, when they are obtained by chemical vapor deposition (CVD), their entangled structure which generates strong van der Waals interactions between their molecules. [0008] In document FR 2 948 233 a conductive composite material is described, obtained from a chemical treatment of sulfur and carbon, introduced into a sealed reactor without external regulation of the pressure within the reactor, at a temperature of between 115° C. and 400° C., for a sufficient amount of time to cause the sulfur to melt and equilibrium to be reached. This material is in the form of particles of sulfur covered with carbon having a low specific surface area. The process for introducing carbon into sulfur, described in this document, is only applicable to carbon-based nanofillers without form factor or aggregation. [0009] There therefore remains a need to have a means which makes it possible to simply and homogeneously disperse carbon nanotubes in elemental sulfur, in order to “dope” the sulfur to give it the mechanical and/or conductive properties necessary for the envisaged application. It would then be advantageous for the compounder to have a powder of sulfur comprising well dispersed CNTs, in the form of ready-to-use masterbatches. [0010] The applicant has discovered that this requirement could be met by carrying out a process comprising bringing CNTs into contact with elemental sulfur via the melt route in a compounding device, followed by transformation of the mixture obtained into a fine powder by conventional grinding techniques. [0011] It has moreover become apparent that this invention could also be applied to carbon-based nanofillers other than CNTs, in particular to carbon nanofibers, to graphene and to carbon black, or mixtures thereof in any proportions. [0012] In addition, the invention may more generally be applied to “sulfur donor” sulfur-based materials. SUMMARY OF THE INVENTION [0013] A subject of the invention is a process for preparing a masterbatch comprising from 0.01% to 50% by weight of carbon-based nanofillers, comprising: (a) introducing at least one sulfur-based material, carbon-based nanofillers, and optionally a rheology modifier into a compounding device; (b) melting the sulfur-based material; (c) kneading the molten sulfur-based material and the carbon-based nanofillers and optionally the rheology modifier; (d) recovering the mixture obtained in an agglomerated solid physical form; (e) optionally grinding the mixture into a powder. [0019] “Carbon-based nanofiller” denotes a filler comprising at least one element from the group formed of carbon nanotubes, carbon nanofibers, graphene, and carbon black, or a mixture thereof in any proportions. Preferably, the carbon-based nanofillers are carbon nanotubes, alone or in a mixture with graphene. [0020] “Sulfur-based material” is intended to mean elemental sulfur or “sulfur donor” compounds such as sulfur-based organic polymers or compounds and sulfur-based inorganic compounds such as anionic polysulfides of alkali metals. [0021] According to a preferred embodiment of the invention, elemental sulfur is used as the sulfur-based material, alone or in a mixture with at least one other sulfur-based material. [0022] Compounding devices have never been used to produce an intimate mixture of molten sulfur and carbon-based nanofillers. [0023] Sulfur is solid at room temperature and becomes liquid starting at 115° C. (melting point). [0024] One of the drawbacks of liquid sulfur is that its viscosity varies greatly, and non-linearly, as a function of the temperature. In order to overcome these drawbacks linked to the unstable viscosity, one of the technical restrictions of the compounding device is a relatively tight window for the melt process. The rheology of the loaded liquid sulfur must be controlled with perfect management of the process operating conditions, optionally using additives which reduce the viscosification above 140° C. [0025] The process according to the invention makes it possible to create homogeneous combining of the particles of carbon-based nanofillers with the sulfur, thereby giving it mechanical and/or conductive properties which are exploited in numerous applications. [0026] Another subject of the invention is the masterbatch able to be obtained according to the process described above. [0027] Another aspect of the invention relates to the use of the masterbatch as elastomer vulcanization agent for the manufacture of bodywork or sealing joints, tires, soundproofing plates, static charge dissipaters, internal conductive layers for high-voltage and medium-voltage cables, or antivibration systems such as motor vehicle shock absorbers, or in the manufacture of structural components for bullet-proof vests or as active material for the manufacture of electrodes for Li/S batteries or supercapacitors, without this list being limiting. [0028] The invention also deals with a solid composition comprising from 0.01 to 50% by weight, preferably from 1 to 30% by weight, of carbon-based nanofillers dispersed in a sulfur-based material, and also to the various uses thereof. BRIEF DESCRIPTION OF THE FIGURES [0029] FIG. 1 illustrates, on an SEM, the morphology of the S/CNT masterbatch obtained in example 1 according to the invention. [0030] FIG. 2 represents the particle size distribution of the powder obtained in example 1 according to the invention. [0031] FIG. 3 illustrates, by SEM, the homogeneous bulk morphology of a particle of the powder obtained in example 1 according to the invention. DETAILED DESCRIPTION OF THE INVENTION [0032] The invention is now described in greater detail and nonlimitingly in the following description. [0033] The process according to the invention is carried out in a compounding device. [0034] According to the invention, “compounding device” is intended to mean an apparatus conventionally used in the plastics industry for melt mixing thermoplastic polymers and additives with a view to producing composites. [0035] This type of apparatus has never been used for producing an intimate mixture of sulfur and/or of sulfur-based material and carbon-based nanofillers. In this apparatus, the sulfur-based material and the carbon-based nanofillers are mixed by means of a device with high shear, for example a co-rotating twin-screw extruder or a co-kneader. The molten material generally leaves the apparatus in an agglomerated solid physical form, for example in the form of granules, or in the form of rods which are cut into granules after cooling. [0036] Examples of co-kneaders which may be used according to the invention are the BUSS® MDK 46 co-kneaders and those of the BUSS® MKS or MX series, sold by BUSS AG, which all consist of a screw shaft provided with flights, placed in a heated barrel optionally made up of several parts, and the internal wall of which is provided with kneading teeth designed to cooperate with the flights so as to shear the kneaded material. The shaft is rotated, and given an oscillatory movement in the axial direction, by a motor. These co-kneaders may be equipped with a granulation system, for example fitted at their exit orifice, which may consist of an extrusion screw or a pump. [0037] The co-kneaders that may be used according to the invention preferably have an L/D screw ratio ranging from 7 to 22, for example from 10 to 20, whereas co-rotating extruders advantageously have an L/D ratio ranging from 15 to 56, for example from 20 to 50. [0038] In order to achieve optimal dispersion of the carbon-based nanofillers in the sulfur-based material in the compounding device, it is necessary to apply a large amount of mechanical energy, which is preferably greater than 0.05 kWh/kg of material. [0039] The compounding step is carried out at a temperature higher than the melting point of the sulfur-based material. In the case of elemental sulfur, the compounding temperature may range from 120° C. to 150° C. In the case of other types of sulfur-based material, the compounding temperature depends on the material specifically used, the melting point of which is generally given by the supplier of the material. The residence time will also be adapted to the nature of the sulfur-based material. [0040] The Sulfur-Based Material [0041] Various sources of elemental sulfur are commercially available. The particle size of the elemental sulfur powder may vary within wide limits. The elemental sulfur may be used as is, or the sulfur may be purified beforehand according to various techniques such as refining, sublimation or precipitation. [0042] The elemental sulfur or sulfur-based material may also be subjected to a preliminary stage of grinding and/or sieving in order to reduce the size of the particles and to narrow their distribution. [0043] Mention may be made, as sulfur-based materials chosen from sulfur-based organic polymers or compounds, of organic polysulfides, organic polythiolates including, for example, functional groups such as dithioacetal, dithioketal or trithioorthocarbonate, aromatic polysulfides, polyether-polysulfides, salts of polysulfide acids, thiosulfonates [—S(O) 2 —S—], thiosulfinates [—S(O)—S—], thiocarboxylates [—C(O)—S—], dithiocarboxylates [—RC(S)—S—], thiophosphates, thiophosphonates, thiocarbonates, organometallic polysulfides or mixtures thereof. [0044] Examples of such organosulfur-based compounds are especially described in document WO 2013/155038. [0045] According to the invention, use may be made, as sulfur-based material, of a sulfur-based inorganic compound, for example chosen from anionic polysulfides of alkali metals, such as lithium. [0046] According to a particular embodiment of the invention, the sulfur-based material is an aromatic polysulfide. [0047] Aromatic polysulfides correspond to the following general formula (I): [0000] [0048] in which: R 1 to R 9 represent, identically or differently, a hydrogen atom, an —OH or —O − M + radical, or a saturated or unsaturated carbon-based chain comprising from 1 to 20 carbon atoms, or an —OR 10 group, with Rio possibly being an alkyl, arylalkyl, acyl, carboxyalkoxy, alkyl ether, silyl or alkylsilyl radical comprising from 1 to 20 carbon atoms. M represents an alkali metal or alkaline earth metal, n and n′ are two integers which are identical or different, each being greater than or equal to 1 and less than or equal to 8, p is an integer between 0 and 50, and A is a nitrogen atom, a single bond or a saturated or unsaturated carbon-based chain of 1 to 20 carbon atoms. [0054] Preferably, in formula (I): R 1 , R 4 and R 7 are O − M + radicals, R 2 , R 5 and R 8 are hydrogen atoms, R 3 , R 6 and R 9 are saturated or unsaturated carbon-based chains comprising from 1 to 20 carbon atoms, preferably from 3 to 5 carbon atoms, the mean value of n and of n′ is approximately 2, the mean value of p is between 1 and 10, preferably between 3 and 8. (These mean values are calculated by those skilled in the art from proton NMR data and by assaying the sulfur by weight). A is a single bond connecting the sulfur atoms to the aromatic rings. [0061] Such poly(alkylphenol) polysulfides of formula (I) are known and may be prepared, for example, in two steps: [0062] 1) reaction of sulfur monochloride or dichloride with an alkylphenol, at a temperature of between 100 and 200° C., according to the following reaction: [0000] [0063] The compounds of formula (II) are especially sold by Arkema under the name Vultac®. [0064] 2) reaction of the compound (II) with a metal derivative comprising the metal M, such as, for example, an oxide, a hydroxide, an alkoxide or a dialkylamide of this metal, in order to obtain O − M + radicals. [0065] According to a more preferred variant, R is a tert-butyl or tert-pentyl radical. [0066] According to another preferred variant of the invention, use is made of a mixture of compounds of formula (I) in which 2 of the R radicals present on each aromatic unit are carbon-based chains comprising at least one tertiary carbon via which R is connected to the aromatic ring. [0067] The Carbon-Based Nanofillers [0068] The amount of carbon-based nanofillers represents from 0.01% to 50% by weight, preferably from 1% to 30% by weight, more preferentially from 5% to 25% by weight relative to the total weight of the masterbatch. [0069] According to the invention, the carbon-based nanofillers are carbon nanotubes, carbon nanofibers, graphene or carbon black or a mixture thereof in any proportions. The carbon-based nanofillers are preferably carbon nanotubes, alone or in a mixture with at least one other carbon-based conductive filler, preferably with graphene. [0070] The carbon nanotubes participating in the composition of the masterbatch may be of the single-walled, double-walled or multi-walled type. The double-walled nanotubes may especially be prepared as described by Flahaut et al. in Chem. Com. (2003), 1442. The multi-walled nanotubes may for their part be prepared as described in document WO 03/02456. [0071] The carbon nanotubes used according to the invention customarily have a mean diameter ranging from 0.1 to 200 nm, preferably from 0.1 to 100 nm, more preferentially from 0.4 to 50 nm and better still from 1 to 30 nm, or even from 10 to 15 nm, and advantageously have a length of more than 0.1 μm and advantageously from 0.1 to 20 μm, preferably from 0.1 to 10 μm, for example approximately 6 μm. Their length/diameter ratio is advantageously greater than 10 and most often greater than 100. These nanotubes thus especially comprise “VGCF” nanotubes (carbon fibers obtained by chemical vapor deposition or Vapor Grown Carbon Fibers). The specific surface area thereof is for example between 100 and 300 m 2 /g, advantageously between 200 and 300 m 2 /g, and the apparent density thereof may especially be between 0.01 and 0.5 g/cm 3 and more preferentially between 0.07 and 0.2 g/cm 3 . The multi-walled carbon nanotubes may for example comprise from 5 to 15 sheets and more preferentially from 7 to 10 sheets. [0072] These nanotubes may be treated or untreated. [0073] An example of crude carbon nanotubes is especially the tradename Graphistrength® C100 from Arkema. [0074] These nanotubes may be purified and/or treated (for example oxidized) and/or ground and/or functionalized. [0075] The grinding of the nanotubes may especially be carried out under cold conditions or under hot conditions and can be carried out according to the known techniques employed in apparatus such as ball, hammer, edge runner, knife or gas jet mills or any other grinding system capable of reducing the size of the entangled network of nanotubes. It is preferable for this grinding step to be carried out according to a gas jet grinding technique and in particular in an air jet mill. [0076] The crude or ground nanotubes can be purified by washing using a sulfuric acid solution, so as to free them from possible residual inorganic and metallic impurities, such as, for example, iron, originating from their preparation process. The weight ratio of the nanotubes to the sulfuric acid may especially be between 1:2 and 1:3. The purification operation can furthermore be carried out at a temperature ranging from 90° C. to 120° C., for example for a duration of 5 to 10 hours. This operation may advantageously be followed by steps in which the purified nanotubes are rinsed with water and dried. In a variant, the nanotubes may be purified by high-temperature heat treatment, typically at greater than 1000° C. [0077] The nanotubes are advantageously oxidized by bringing them into contact with a solution of sodium hypochlorite containing from 0.5 to 15% by weight of NaOCl and preferably from 1 to 10% by weight of NaOCl, for example in a weight ratio of the nanotubes to the sodium hypochlorite ranging from 1:0.1 to 1:1. The oxidation is advantageously carried out at a temperature of less than 60° C. and preferably at room temperature, for a duration ranging from a few minutes to 24 hours. This oxidation operation may advantageously be followed by steps in which the oxidized nanotubes are filtered and/or centrifuged, washed and dried. [0078] The nanotubes can be functionalized by grafting reactive units, such as vinyl monomers, to the surface of the nanotubes. The constituent material of the nanotubes is used as radical polymerization initiator after having been subjected to a heat treatment at more than 900° C., in an anhydrous medium devoid of oxygen, which is intended to remove the oxygen-comprising groups from its surface. It is thus possible to polymerize methyl methacrylate or hydroxyethyl methacrylate at the surface of carbon nanotubes. [0079] Use is preferably made in the present invention of optionally ground crude carbon nanotubes, that is to say nanotubes which are neither oxidized nor purified nor functionalized and which have not been subjected to any other chemical and/or heat treatment. [0080] Moreover, use is preferably made of carbon nanotubes obtained from a renewable starting material, in particular of plant origin, as described in Application FR 2 914 634. [0081] Carbon nanofibers are, like carbon nanotubes, nanofilaments produced by chemical vapor deposition (or CVD) starting from a carbon-based source which is decomposed on a catalyst comprising a transition metal (Fe, Ni, Co, Cu), in the presence of hydrogen, at temperatures of 500° C. to 1200° C. However, these two carbon-based fillers differ in their structure (I. Martin-Gullon et al., Carbon, 44 (2006), 1572-1580). This is because carbon nanotubes consist of one or more graphene sheets wound concentrically around the axis of the fiber to form a cylinder having a diameter of 10 to 100 nm. Conversely, carbon nanofibers are composed of more or less organized graphite regions (or turbostratic stacks), the planes of which are inclined at variable angles relative to the axis of the fiber. These stacks may take the form of platelets, fishbones or dishes stacked in order to form structures having a diameter generally ranging from 100 nm to 500 nm, or even more. [0082] Moreover, use is preferably made of carbon nanofibers having a diameter of 100 to 200 nm, for example of approximately 150 nm (VGCF® from Showa Denko), and advantageously a length of 100 to 200 μm. [0083] Graphene denotes a flat, isolated and separate graphite sheet but also, by extension, an assemblage comprising between one and a few tens of sheets and exhibiting a flat or more or less wavy structure. This definition thus encompasses FLGs (Few Layer Graphene), NGPs (Nanosized Graphene Plates), CNSs (Carbon NanoSheets) and GNRs (Graphene NanoRibbons). On the other hand, it excludes carbon nanotubes and nanofibers, which respectively consist of the winding of one or more graphene sheets coaxially and of the turbostratic stacking of these sheets. Furthermore, it is preferable for the graphene used according to the invention not to be subjected to an additional step of chemical oxidation or of functionalization. [0084] The graphene used according to the invention is obtained by chemical vapor deposition or CVD, preferably according to a process using a pulverulent catalyst based on a mixed oxide. It is characteristically in the form of particles having a thickness of less than 50 nm, preferably of less than 15 nm, more preferentially of less than 5 nm, and having lateral dimensions of less than a micron, preferably from 10 nm to less than 1000 nm, more preferably from 50 to 600 nm, or even from 100 to 400 nm. Each of these particles generally includes from 1 to 50 sheets, preferably from 1 to 20 sheets and more preferentially from 1 to 10 sheets, or even from 1 to 5 sheets, which are capable of being separated from one another in the form of independent sheets, for example during a treatment with ultrasound. [0085] Carbon black is a colloidal carbon-based material manufactured industrially by incomplete combustion of heavy petroleum products and which is in the form of carbon spheres and of aggregates of these spheres, the dimensions of which are generally between 10 and 1000 nm. [0086] The process according to the invention makes it possible to efficiently and homogeneously disperse a large amount of carbon-based nanofillers in the sulfur-based material. The carbon-based nanofillers are thus dispersed homogeneously throughout the mass of particles, and are not solely found at the surface of the sulfur-based particles as described in document FR 2 948 233. [0087] In addition, it is possible to add, during the compounding step, an additive which modifies the rheology of the sulfur-based material, such as sulfur in the molten state, in order to reduce the self-heating of the mixture in the compounding device. Such additives having a fluidizing effect on the liquid sulfur are described in Application WO 2013/178930. Mention may be made, by way of examples, of dimethyl sulfide, diethyl sulfide, dipropyl sulfide, dibutyl sulfide, dimethyl disulfide, diethyl disulfide, dipropyl disulfide, dibutyl disulfide, the trisulfide homologs thereof, the tetrasulfide homologs thereof, the pentasulfide homologs thereof, the hexasulfide homologs thereof, alone or in mixtures of two or more thereof in any proportions. [0088] The amount of rheology-modifying additive is generally between 0.01% to 5% by weight, preferably from 0.1% to 3% by weight relative to the total weight of the masterbatch. [0089] According to a particular aspect of the invention, at least one additive may be introduced into the compounding device. The nature of the additive will be adapted to the final use of the ready-to-use masterbatch. [0090] As additives, mention may for example be made of vulcanization accelerators or activators, lubricants, pigments, stabilizers, fillers or reinforcers, antistatic agents, fungicides, flame retardants, solvents, ionic conductors, or binders, without this list being limiting. [0091] At the outlet of the compounding device, the masterbatch is in the agglomerated physical form, for example in the form of granules. [0092] In a final step, the masterbatch may be subjected to a grinding step according to techniques well known to those skilled in the art, so as to obtain a masterbatch in powder form. Use may be made, as apparatus, of a hammer mill, a bead mill, an air jet mill or a planetary mixer. At the end of this stage, the desired median diameter D 50 will depend on the use of the masterbatch and is generally between 1 and 60 μm, preferably between 10 and 50 μm, preferably between 10 and 20 μm. [0093] At the end of the process according to the invention, a masterbatch is obtained having carbon-based nanofillers well dispersed in the mass of the particles. This morphology can be confirmed in particular by observation using a transmission electron microscope or a scanning electron microscope. [0094] The invention thus relates to a solid composition comprising from 0.01 to 50% by weight, preferably from 1 to 30% by weight, and more preferably from 5 to 25% by weight of carbon-based nanofillers dispersed in a sulfur-based material. [0095] The solid composition may also comprise at least one additive chosen from rheology modifiers, vulcanization accelerators or activators, lubricants, pigments, stabilizers, fillers or reinforcers, antistatic agents, fungicides, flame retardants, solvents, ionic conductors, or binders, or the combination thereof. [0096] The solid composition may be obtained according to the process described above and may be in powder form after grinding. The powder has particles with a median diameter D 50 of between 1 and 60 μm, preferably between 10 and 50 μm. [0097] The composition according to the invention is advantageously used for the manufacture of bodywork or sealing joints, tires, soundproofing plates, static charge dissipaters, internal conductive layers for high-voltage and medium-voltage cables, or antivibration systems such as motor vehicle shock absorbers, or in the manufacture of structural components for bullet-proof vests or for the manufacture of electrodes for Li/S batteries or supercapacitors. [0098] The masterbatch able to be obtained following the process according to the invention or the solid composition according to the invention may be used in conventional applications for sulfur, or more generally for sulfur-based materials, but it also makes it possible to develop novel applications which require mechanical reinforcement or electronic conductivity provided by the presence of carbon-based nanofillers within the sulfur-based material. [0099] The invention will now be illustrated by the following examples, the objective of which is not to limit the scope of the invention, defined by the appended claims. EXPERIMENTAL SECTION Example 1: Preparation of an S/CNT Masterbatch [0100] CNTs (Graphistrength® C100 from ARKEMA) and solid sulfur (50-800 μm) were introduced into the first feed hopper of a BUSS® MDK 46 (L/D=11) co-kneader fitted with a discharge extrusion screw and a granulation device. [0101] The temperature settings within the co-kneader were as follows: Zone 1: 140° C.; Zone 2: 130° C.; Screw: 120° C. [0102] At the outlet of the die, the masterbatch consisting of 85% by weight of sulfur and 15% by weight of CNT is in the form of granules obtained by pelletizing, cooled by a water jet. Observation by scanning electron microscope (SEM) showed that the CNTs were well dispersed in the sulfur ( FIG. 1 ). [0103] The granules obtained were dried to a moisture content <100 ppm. [0104] The dry granules were then ground in a hammer mill, cooling being provided by nitrogen. [0105] A powder with a D 50 of between 10 and 15 μm, and D100<50 μm, was obtained. FIG. 2 represents the particle size distribution of the powder and highlights the absence of particles larger than 50 μm in size, making it possible to avoid the formation of defects during the use of this powder for the production of cathodes for Li/S batteries. [0106] FIG. 3 uses scanning electron microscopy to show the homogeneous bulk morphology of a particle. [0107] This powder consisting of 85% by weight of sulfur and 15% by weight of CNT can be used, for example, for the preparation of an active material for electrodes for Li/S batteries, or of a base EPDM formulation for application in profiled elements in the automotive industry. Example 2: Preparation of an S/DMDS/CNT Masterbatch [0108] CNTs (Graphistrength® C100 from ARKEMA) and solid sulfur (50-800 μm) were introduced into the first feed hopper of a BUSS® MDK 46 (L/D=11) co-kneader fitted with a discharge extrusion screw and a granulation device. [0109] Liquid dimethyl disulfide (DMDS) was injected into the 1 st zone of the co-kneader. [0110] The temperature settings within the co-kneader were as follows: Zone 1: 140° C.; Zone 2: 130° C.; Screw: 120° C. [0111] At the outlet of the die, the masterbatch consisting of 78% by weight of sulfur, 2% by weight of DMDS and 20% by weight of CNT is in the form of granules obtained by pelletizing, cooled by a water jet. [0112] The granules obtained were dried to a moisture content <100 ppm. [0113] The dry granules were then ground in a hammer mill, cooling being provided by nitrogen. [0114] A powder having a median diameter D 50 of between 10 and 15 μm was obtained, which can be used for the preparation of an electrode for Li/S batteries. Example 3: Preparation of an S/Poly(Tert-Butylphenol) Disulfide/CNT Masterbatch [0115] CNTs (Graphistrength® C100 from ARKEMA) and solid sulfur (50-800 μm) were introduced into the first feed hopper of a BUSS® MDK 46 (L/D=11) co-kneader fitted with a discharge extrusion screw and a granulation device. [0116] Liquid dimethyl disulfide (DMDS) was injected into the 1 st zone of the co-kneader. [0117] The poly(tert-butylphenol) disulfide sold under the name VULTAC-TB7® from Arkema was premixed with an Li salt, sold under the name LOA (Lithium 4,5-dicyano-2-(trifluoromethyl)imidazole) by Arkema, then introduced into the first hopper by means of a 3 rd metering device. [0118] The temperature settings within the co-kneader were as follows: Zone 1: 140° C.; Zone 2: 130° C.; Screw: 120° C. [0119] At the outlet of the die, the mixture is in the form of granules obtained by pelletizing, cooled by a water jet. [0120] The granules obtained were dried to a moisture content <100 ppm. [0121] The dry granules were then ground in a hammer mill, cooling being provided by nitrogen. [0122] A powder consisting of 77% by weight of sulfur, 2% by weight of DMDS and 15% by weight of CNT, 5% of VULTAC-TB7°, 1% of LOA, having a D 50 of between 10 and 15 μm is obtained, which can be used for the preparation of an electrode for Li/S batteries. Example 4: Preparation of an S/Poly(Tert-Butylphenol) Disulfide/Stearic Acid/ZnO/CNT Masterbatch [0123] CNTs (Graphistrength® C100 from ARKEMA) were introduced into the first feed hopper of a BUSS® MDK 46 (L/D=11) co-kneader fitted with a discharge extrusion screw and a granulation device. [0124] The poly(tert-butylphenol) disulfide sold under the name VULTAC-TB7® from Arkema was premixed with solid sulfur and stearic acid and ZnO in powder form, then introduced into the first hopper by the second metering device. [0125] The temperature settings within the co-kneader were as follows: Zone 1: 140° C.; Zone 2: 130° C.; Screw: 120° C. [0126] At the outlet of the die, the masterbatch consisting by weight of 20% of sulfur, 20% of CNT, 20% of VULTAC TB7®, 15% of stearic acid and 25% of ZnO, is in the form of granules obtained by pelletizing, cooled by a water jet. [0127] The granules obtained were dried to a moisture content <100 ppm. [0128] This masterbatch may be used as vulcanization agent for the manufacture of motor vehicle shock absorbers.

The invention relates to a method for producing a master batch comprising between 0.01 and 50 wt. % of carbonaceous nanofillers and at least one sulphurated material such as elemental sulphur by melt compounding, and to the master batch thus produced and the different uses thereof. The invention also relates to a solid composition comprising carbonaceous nanofillers dispersed in a sulphurated material.

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is related to U.S. patent application Ser. No. 12/942,248 filed Nov. 9, 2010 and entitled “Methods for Identifying the Guarantor of an Application,” to U.S. patent application Ser. No. 12/119,617 filed May 13, 2008 and entitled “Multi-Channel Multi-Factor Authentication,” now U.S. Pat. No. 8,006,291, and to U.S. patent application Ser. No. 12/137,129 filed Jun. 11, 2008 and entitled “Single-Channel Multi-Factor Authentication,” each of which is incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates generally to the field of authentication and more particularly to the field of software distribution. [0004] 2. Related Art [0005] End-user-software-licensing policies implemented by software vendors pose challenges to users since end-user-software-licenses often are machine licenses. For instance, it is not uncommon for end-users to install software on a particular machine, enter a license-key and thereby activate the software. Vendors can limit the number of software activations by limiting the number of activations for any particular license-key. The activations are associated with the machines on which the software is installed, not the end-user. [0006] Many End-User-Software-License-Agreements (EULAs) specify that the end-user may install and use a vendors' software on a limited number of devices. For instance, Adobe® allows installation of some software products on two machines. Each of the installations on the two machines may be active simultaneously. A new activation of the software on a third machine requires the user to deactivate an installation of the software on at least one of the activated software installations. The number of activations is controlled through a network interface, commonly the Internet. [0007] In cases where a machine becomes inoperable or becomes unavailable, manual intervention by the vendor, license agent, or other entity controlling licenses is required to transfer a license to another operable machine. The procedure to allow users to transfer a license often involves revoking the current license and issuing a new license. The procedure for manually revoking licenses is expensive for vendors and inconvenient for licensed users. [0008] To circumvent these vendor software license policies, some users install and activate software on as many machines as authorized by a license, then call the vendor and falsely claim that one or more machines have been stolen, or failed, and that they require additional activations under their license, thereby pirating additional copies of the software. [0009] FIG. 1 schematically illustrates components used in a typical software license activation procedure according to the prior art. A user 100 obtains a software installation image, for example, via digital media 110 such as a CD ROM, DVD ROM, memory stick, etc. Alternatively, the user may obtain the software installation image via a network interface such as the Internet 120 from a file server such as an FTP server 130 . The software installation image is made available to the software installation platform, the machine on which the software installation image will be executed by the user 100 , for example, a PC 140 or smartphone 150 . [0010] After the software is installed from the installation image, it must be activated before it can be used long term. In many cases, vendors provide a grace period, during which the installed software can be used prior to activation. The grace period can provide the user 100 with an opportunity to try the software before activating it. The grace period can also allow users 100 to operate the software immediately in those cases where a network connection or telephone connection to the vendor's license authorization server 150 is not available to activate the software license. [0011] The software license activation procedure, whether or not a grace period is allowed, requires the user 100 to communicate a software license key 160 to a license authorization server 170 . The software license key 160 is also known as a software-installation-key in the art. Communication of the software license key 160 can be performed through the installed software, or over the phone 180 through an automated system or by vendor personnel. [0012] License authorization server 170 maintains a record of the number of activations available for each software license key 160 . When the license authorization server 170 receives an activation request including the software license key 160 , the license authorization server 170 determines whether any activations remain available and if so, the license authorization server 170 sends an activation code to the software installed on the platform 140 , 150 to fully activate the software. If no activations remain for the given license key 160 , the software is not activated. [0013] The user experience, when activating software for first time use, begins by obtaining a software installation image. The user 100 then starts the software installation, which will prompt the user 100 to provide the software license key 160 from a package or an e-mail, for example. The software license key 160 can be provided, as noted above, through the installation software on the platform 140 , 150 or through another channel such as over the phone, for instance. The user 100 then waits for the installation to complete, during which time the license authorization server 170 verifies the software license key 160 and provides an activation code. Once installation is complete, in many instances, the user 100 must activate the software license by accepting the terms. Then the software is fully functional on the platform 140 , 150 . [0014] In addition to tracking the numbers of remaining activations available for each software license key 160 , the license authorization server 170 can also store activation information in association with the activations that have already been used. Such information can identify the platform 140 , 150 , indicate a customer name, a location, an IP address, and so forth, and can be stored in databases, back-up storage, digital lockers associated with customer accounts, etc. [0015] The license authorization server 170 , during the activation process, commonly gathers information and in particular associates the software license key 160 with the platform 140 , 150 . There exist a number of methods for making this association including computing a machine signature that is sent to the license authorization server 170 , writing license key values (usually encrypted) to the local disk, broadcasting license information on the local subnet, writing activation data to registry databases on the local machine, making contact with a license server over the network, etc. [0016] For large organizations that license software for distribution to a large user population, the software license key 160 is distributed to users 100 to activate the software on their respective platforms 140 , 150 . The license authorization server 170 keeps an activation count for the particular software license key 160 until the limit set by the license is reached, after which no more activations are allowed. This procedure ultimately associates the software license with the platforms 140 , 150 on which activations were successfully completed. [0017] Another way that multiple activations for a license can be handled is with a local license server (not shown in FIG. 1 ). Each time a user 100 executes the software, a license is allocated from a pool of licenses. When the server license pool is empty, no further activations are allowed. Graceful exit of the software returns the license to the pool allowing another platform 140 , 150 to execute the software. [0018] A common method for associating a software license key 160 with a platform 140 , 150 when activating a standalone license is to use a computed machine signature to determine if the software is active. For instance, in some implementations a machine signature comprises, or is computed from, one or more hardware characteristics such as the Media Access Control (MAC) address of an onboard network card, a CPU serial number, a disk serial number, model, disk drive manufacturer, disk drive size, graphics adapter, etc. [0019] The machine signature mechanism prevents users 100 from cloning the disk drive, moving the clone to a second platform 140 , 150 and operating the software on the second platform 140 , 150 . An attempt to get an activated copy running from a cloned disk, for example, results in a request to activate the software since the CPU and disk drive characteristics do not result in a machine signature matching the first activation machine signature. [0020] Another strategy is a variation of the standalone activation just described. In this variant method a machine signature is computed and sent to the license authorization server 170 operated by the licensor. The machine signature is computed at activation time. Each time the software is started, the machine signature is verified. If the software is not activated, the software does not proceed. [0021] It is worth noting that verifying the activation each time the software is started simplifies transferring licenses. A user can install the software on any number of platforms 140 , 150 . Using an authentication procedure, usually a user name and password, a user 100 can de-activate the software on a particular platform 140 , 150 . Then the user 100 can activate the software on another platform 140 , 150 for immediate use. In this way the license can float, or more precisely be transferred to any platform 140 , 150 that the user 100 chooses. Once de-activated, the software cannot be used on the prior platform 140 , 150 , though it remains installed. [0022] The strategy of verifying the activation each time the software is started has a severe drawback, however. Since the signature of the platform 140 , 150 to be de-activated is only stored on the platform 140 , 150 , to which, it is associated, a machine failure results in the loss of the license. Thus, if the platform 140 , 150 fails while holding an activated license, there is no way to start the software to deactivate the license. [0023] Other license activation strategies exist. For instance, software can periodically broadcast messages on a Local Area Network (LAN) to determine if other instances of the software are running. If another is found, the first is disabled. Despite the various strategies in use, no existing licensing strategy associates the software license key 160 to the user 100 personally. Instead, software licensing and activations are associated with machines on which the software is installed or the network environment in which the software is executing, and based on authentication methods such as username/password that identify accounts. [0024] Using the most widely deployed software license activation practices not only leads to user inconvenience but it also facilitates software piracy. For example, the failure of a platform 140 , 150 requires a vendor to allow a user 100 to transfer a license to another. In many cases, license transfers are performed without verifying that a failure actually occurred. For a user 100 , an equipment failure is bad enough, and having to go through the vendor to transfer a license is a further inconvenience. For the vendor, the transfer usually requires staff intervention making the transfer an unwanted expense. However, for the software pirate, it is an easy way to obtain licenses for additional platforms 140 , 150 at low cost. SUMMARY [0025] The present invention provides methods for activating software on an installation platform such as a PC, smartphone, or tablet computer, and systems of one or more servers in communication with one another for implementing such methods. An exemplary method of the present invention comprises a step of receiving, with a first computing system, a software license key and first identifying information followed by a step of storing the software license key in association with the first identifying information, such as in a record of a database of a computer-readable memory. The receive software license key is encrypted in some embodiments, while in other embodiments the software license key and the first identifying information are contained within an encrypted envelope, and in some of these embodiments the software license key and the first identifying information are each separately encrypted as well. The first identifying information can comprise a machine signature and personal information, for example. In further embodiments, receiving the first software license key comprises receiving a hash of the first software license key. [0026] The exemplary method further comprises a step of receiving a first biometric sample, either with the same or a second computing system, and storing the first biometric sample as a biometric template in association with the software license key. The method additionally comprises a step of sending a first activation code from either computing system to the installation platform upon completion of the user enrollment. Examples of the first biometric sample include a voice sample and an image of the user. [0027] When the user wishes to transfer the license from one platform to another, the exemplary method further comprises, after sending the first activation code in the first instance, receiving the software license key and second identifying information, receiving a second biometric sample, matching the second biometric sample with the biometric template previously associated to the software license key, and then sending a second activation code. In some instances the first and second activation codes are the same. [0028] In systems of the present invention, the one or more servers include logic configured to perform the noted method steps. As used herein, “logic” means a physical system capable of carrying out a defined series of steps. Logic as used herein can form part of a server, or other computing system capable of serving multiple network connections, and can comprise application-specific integrated circuits (ASICs) specially designed to perform the series of steps, firmware programmed to perform the series of steps, a microprocessor in combination with software stored on a computer-readable medium specifying the series of steps, or any combination of these. It will be understood that logic as used herein specifically excludes software alone. Additionally, “computer-readable medium” as used herein specifically excludes paper and transitory media such as carrier waves. Systems of the present invention also comprise computer-readable media to maintain databases for data storage. [0029] Methods for activating software are also provided. An exemplary method, performed by a user, can comprise or consist essentially of installing an instance of the software on a platform and activating the instance on the platform by submitting a software license key and a biometric sample, and then receiving, with the installation platform, an activation code in response to submitting the biometric sample. The user can repeat this process with another platform to readily transfer the license to the other platform even when the software license agreement does not allow for additional activations. In such a situation a previously activated software instance on another platform is deactivated. BRIEF DESCRIPTION OF DRAWINGS [0030] FIG. 1 is a schematic representation of an exemplary system for activating licensed software according to the prior art. [0031] FIG. 2 is a schematic representation of an exemplary system for carrying out various methods described herein. [0032] FIG. 3 is a flowchart representation of a method for activating software according to an exemplary embodiment of the present invention. [0033] FIG. 4 is a flowchart representation of a further method for activating software according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION [0034] The present invention associates the activation of licensed software with the end-user 100 by employing biometrics identification technologies. Associating the user 100 with the software license fulfills the expectation of the user 100 and allows the vendor to enforce a licensing policy. The user 100 is associated with the software license by associating user biometrics with a software license key for the software license. Accordingly, the present invention better allows vendors to meet the expectations of End-User-License-Agreements (EULAs) that purport to allow users 100 to have control over where they install and use purchased software products. Further, the current invention prevents fraud by associating licenses with people rather than hardware that may or may not be active. [0035] FIG. 2 schematically illustrates components used in a software license activation procedure according to an exemplary embodiment of the present invention that associates a software license key 160 with a user 100 , a physical person, through the use of biometrics. Biometrics requires the user 100 to submit a sample of a particular biometric characteristic or behavior. Once submitted, the submitted sample is enrolled, meaning that it is associated with the user 100 , such as by association with a unique identifier such as a user ID or account number. The enrolled biometric reference sample can be compared to future submissions to identify or verify the identity of the person. For instance, a fingerprint can be used to automatically identify a person using a fingerprint scanner, computing equipment, and software. A user 100 submits an initial fingerprint sample by swiping a finger over the scanner and this sample is stored as a template for comparison. At a later time, the same user 100 can prove their identity by again swiping the finger. [0036] Biometric enrollment samples, and subsequent authentication samples submitted to prove identity, can be sent to a computing system of one or more servers, such as a license authorization server 170 and a biometrics authentication server 200 in communication with one another. Biometric samples for enrollment sent to the biometrics authentication server 200 are stored in association with the software license key 160 . The biometrics authentication server 200 identifies the user 100 (referred to as the claimant when seeking authentication) at a later time by comparing the enrolled biometric sample, saved as a template, with the subsequent biometric sample. If a biometric sample for a user 100 matches the stored biometric template from when the user 100 was enrolled, then the licensed software can be activated by the license authorization server 170 . Although biometrics authentication server 200 and license authorization server 170 are shown in FIG. 2 as separate servers, it will be understood that in some embodiments the functionality of both are integrated into a single server, while in other embodiments their functionalities are divided amongst additional servers. For example, enrollment can be handled by a third server (not shown). [0037] FIG. 3 is a flowchart representation of an exemplary method 300 of the present invention for activating software on an installation platform 140 , 150 . Steps of the activation method 300 can be performed, for example, by a software distributor through a license authorization server 170 and a biometrics authorization server 200 in communication with the installation platform 140 , 150 . The license authorization server 170 and the biometrics authorization server 200 can be the same server, in some embodiments. [0038] Initially, the user 100 installs licensed software from a software installation image, as described above. Once installed, the software is configured to not fully function, either immediately or following some grace period, until the software is activated. At this point the licensed software can prompt the user 100 to request activation, or the software can automatically continue the activation process. In either event, a first communication channel between the installation platform 140 , 150 and the license authorization server 170 is established, for example, by the licensed software. [0039] In a step 305 of the method 300 a software license key 160 and first identifying information are received by a first computing system such as the license authorization server 170 . Some or all of the software license key 160 and the first identifying information can be received over the first communication channel, such as the Internet or a local area network (LAN), while any balance of the software license key 160 and the first identifying information can be received over a second communication channel such as one between a phone 180 and license authorization server 170 . [0040] The software license key 160 can be a string of characters, either numeric or alpha-numeric, for example, XXXXX-XXXXX-XXXXX-XXXXX-XXXXX, where X is an alphanumeric character: A-Z or 0-9. Identifying information can include both information that identifies the installation platform 140 , 150 and information that identifies the user 100 . An example of information that identifies the installation platform 140 , 150 is a machine signature, while information that identifies the user 100 can include personal information such as a name, home address, e-mail address, phone number, and the like. In some embodiments the licensed software encrypts the software license key 160 before transmitting the software license key 160 to the first computing system. In further embodiments, the software license key 160 and the first identifying information are encrypted together resulting in an envelope that can be decrypted by the first computing system. In still further embodiments, the software license key 160 and/or the first identifying information are encrypted before being further encrypted together into the envelope. [0041] Hashing can also be used in the alternative to encryption. Hashing is distinguished in the art from encryption in that an encrypted element can be decrypted to render the original value. Hashing is an irreversible process such that a resultant hash cannot be analogously “unhanshed.” When two entities use the same hash algorithm on a same value the resulting hashes match. The hash can then be compared to determine a match without revealing the original value. [0042] In some instances, once activation is required, the licensed software will open a web browser on the platform 140 , 150 to allow the user 100 to complete the activation process with the license authorization server 170 . In some of these embodiments, the user 100 is prompted through the web browser to enter the software license key 160 , which may be printed on materials that came with the software installation image or may have been received by the user 100 in an e-mail or other electronic communication at the time of purchase. The user 100 can also be prompted to enter personal information. [0043] In some embodiments, the user 100 is asked to call a phone number for the license authorization server 170 , and once connected over the second communication channel to the license authorization server 170 , or a human operator in communication with the license authorization server 170 , the user 100 is prompted to enter the software license key 160 , either verbally or using a number pad on the phone 180 . The user may be enrolled using this second channel. In some of these embodiments the first identifying information can be sent over the first communication channel, while in other embodiments the licensed software encrypts the first identifying information with the software license key 160 and displays the resulting envelope to the user 100 ; the user 100 then is prompted to provide the resulting envelope to the license authorization server 170 over the second communication channel. [0044] In a step 310 of the method 300 the first identifying information is stored in association with the software license key 160 . For example, the first computing system can store the software license key and the first identifying information in a record of a database stored on non-volatile computer-readable medium. In some instances, the envelope itself is stored in association with the software license key 160 . [0045] In a step 315 the user 100 is enrolled. Enrollment entails a sub-step of receiving a first biometric sample from the user 100 with a second computing system and a sub-step of storing the first biometric sample as a biometric template in association with the software license key 160 . The second computing system can be a biometrics authorization server 200 or can be the same computing system as the first computing system. In those embodiments where the second computing system is different than the first computing system, a third communication channel can be established between the installation platform 140 , 150 and the second computing system. [0046] The first biometric sample can comprise a voice sample or an image of the user 100 , in various embodiments. For example, the second computing system can prompt the user 100 to say a word or phrase into a microphone of the platform 140 , 150 or can prompt the user 100 to face a video camera of the platform 140 , 150 . Various alternatives employing single or multiple factors and either a single or multiple communication channels are described in U.S. patent application Ser. Nos. 12/119,617 and 12/137,129 noted above. [0047] Once the first biometric sample has been received, the first biometric sample is stored as a biometric template in association with the software license key 160 . The biometric template can be added, for instance, to the record created previously for associating the software license key 160 with the first identifying information, or can be stored in a separate record in another database. The biometric template can be used in subsequent activation attempts to determine whether a person seeking to activate licensed software has previously been associated with the software license key 160 . [0048] In a step 320 of the method 300 an activation code is sent from the first computing system to the installation platform 140 , 150 upon completion of the user enrollment step 315 . In various embodiments the activation code is encrypted by the first computing system before being communicated to the installation platform 140 , 150 over the first communication channel. When the first computing system completes the enrollment, the first computing system can count an activation against the software license key 160 . This can be done by incrementing a counter associated with the software license key 160 , such as a counter associated with the record that associates the software license key 160 to the first identifying information. [0049] In some embodiments the counter is checked before the step 315 to determine whether the total number of activations granted under the terms of the EULA has been reached. In various embodiments checking the number of granted activations and the total allowed activations occurs in either step 305 or 310 . The method described with respect to FIG. 4 illustrates additional method steps that can be performed in such situations. [0050] Upon receipt of the activation code the licensed software on the platform 140 , 150 compares the received activation code against an expected value and unlocks the functionality of the licensed software if the two match. In some embodiments, the expected value is the encrypted activation code, and in these embodiments the received encrypted activation code does not have to be decrypted to make the comparison. [0051] When a user 100 starts previously activated software on a platform 140 , 150 , the software automatically calculates a machine signature and communicates the same to the license authorization server 170 , if possible. If the machine signature matches the machine signature last stored in association with the software license key 160 the license authorization server 170 takes no action and allows the instance of the software to continue. Otherwise, the lack of a match indicates either an attempted fraud or that the license had previously been transferred to another platform 140 , 150 and therefore the license authorization server 170 deactivates the instance of the software, optionally sending a message that the license was transferred to another platform 140 , 150 . In these situations an offer to purchase another activation can also be made. In various embodiments an envelope including the machine signature is sent and compared against the stored envelope. [0052] FIG. 4 illustrates a method 400 that optionally follows step 320 of method 300 . In a step 405 the first computing system again receives the software license key 160 over a first communications channel, but in association with different identifying information. This second identifying information can include different personal information or different machine signature, or both. The first computing system checks the record for the software license key 160 to determine whether the person seeking to activate the licensed software has previously activated the licensed software, and whether the number of activations equals the number of allowed activations. [0053] In the event that the number of allowed activations has not been equaled, and personal information for the person seeking to activate the licensed software does not match any personal information already stored in association with the software license key 160 , then the first computing system essentially repeats method 300 for the new user, having the new user also enroll in a step 315 , before issuing the activation key in a step 320 . If the number of allowed activations has been equaled, however, and the personal information for the person seeking to activate the licensed software does not match any personal information already stored in association with the software license key 160 , then the new user can be offered an opportunity to purchase an extension of the license in order to increase the number of allowed activations. [0054] If the number of allowed activations has been equaled, and the personal information for the person seeking to activate the licensed software matches the personal information for the user 100 stored in association with the software license key 160 , but the machine signature for the platform 140 , 150 is new, this indicates that the enrolled user 100 is seeking to activate the licensed software on a different platform 140 , 150 . In a step 410 of the method 400 , the first computing system stores the second identifying information in association with the software license key 160 as in step 310 of method 300 . [0055] In a step 415 the user 100 is authenticated. The user 100 is prompted to provide a second biometric sample which is received by the biometrics authorization server 200 . The second biometric sample is matched to the biometric template associated to the software license key 160 to demonstrate that the person seeking to activate the licensed software is actually the same person that was previously enrolled. If the second biometric sample matches the biometric template, then in a step 420 then the activation code is sent over the first communications channel and the new installation platform is activated. The activation code sent in step 420 is not necessarily the same as the activation code sent in step 320 , in some embodiments. For instance, activation codes can be time stamped to make each one different. [0056] It will be appreciated that the total number of activations will exceed the allowed number of activations when the activation code is sent in step 420 and some previously activated platform 140 , 150 will have to be deactivated unless, as above, additional activations are purchased. Thus, in a step 425 a previously activated platform 140 , 150 can be deactivated. Deactivation can be achieved by deleting a machine signature from the record for the software license key 160 , for example. The platform 140 , 150 that is deactivated in step 425 can be selected in a number of ways, with a particular manner specified in the EULA. for example, the first platform 140 , 150 associated with the software license key 160 can be the first to be deactivated, or the last platform 140 , 150 associated with the personal information of the user 100 can be deactivated, or the user 100 can be presented with a list of activated platforms 140 , 150 from which to select one to be deactivated. [0057] When activated licensed software on a platform 140 , 150 has been deactivated, in some embodiments, the licensed software will continue to function normally until that instance of the licensed software is shut down. In these embodiments, currently activated licensed software will connect to the license authorization server 170 upon start-up. If that instance has been marked for deactivation in the interim, the license authorization server 170 can deactivate the licensed software. [0058] In the foregoing specification, the invention is described with reference to specific embodiments thereof, but those skilled in the art will recognize that the invention is not limited thereto. Various features and aspects of the above-described invention may be used individually or jointly. Further, the invention can be utilized in any number of environments and applications beyond those described herein without departing from the broader spirit and scope of the specification. The specification and drawings are, accordingly, to be regarded as illustrative rather than restrictive. It will be recognized that the terms “comprising,” “including,” and “having,” as used herein, are specifically intended to be read as open-ended terms of art.

Methods for software activation are provided that associate a software license key with one or more authorized individuals such that an authorized individual can readily transfer a license between different platforms. A biometric sample of the individual is stored in an enrollment step upon first activation of the software. Later, the same individual can provide a biometric sample that matches the stored biometric sample in order to activate the software on another platform, rendering the first instance inactive if no additional activations are available. More than one individual can be authorized under a license that allows for multiple activations.

TECHNICAL FIELD [0001] The inventive concept relates to a dental instrument, and more particularly, to a dental instrument for cutting soft tissue in the oral cavity to provide soft tissue used for a soft tissue transplantation surgery. BACKGROUND ART [0002] In general, a biomaterial may be divided into hard tissue and soft tissue. Bones or teeth are examples of the hard tissue. Skin, blood vessels, cartilages, or ligaments are examples of the soft tissue. The hard tissue has an elastic coefficient and a tensile strength that are higher than those of the soft tissue. [0003] The soft tissue as a biomaterial has been used in the field of dental treatment. In particular, soft tissue transplantation surgeries have been widely used as a method for rebuilding or treating damaged soft tissues during a dental surgery such as implant surgery. [0004] In case of an implant surgery that is recently in the limelight, gums around an implant need to be healthy so that a tooth implant may be used for a long time. This is the same principle that is used for a case in which a flag driven into sands. The flag does not fall when a large amount of sand exists around the flag. That is, even when an alveolar bone firmly holds the root of a tooth, the tooth may sway when the gum surrounding the tooth is insufficient. Also, exposed nerves may cause pain and it is not aesthetic. In this case, a soft tissue transplantation surgery is needed. [0005] To transplant soft tissues to an area where the thickness of a gum is thin or the gum is lost, soft tissue to be transplanted needs to be primarily obtained. To this end, soft tissues in an amount needed for transplantation are cut off from other normal area in the oral cavity. Typically, soft tissues in the palate of the oral cavity are used because the flesh of the palate is relatively thicker than that of other places. [0006] Dental instruments for cutting soft tissue are used to cut the soft tissue off from the oral cavity to provide soft tissue used for a soft tissue transplantation surgery. [0007] A conventional dental instrument for cutting soft tissue may include a main body equipped with a blade, a cover covering the upper portion of the main body, and a handle coupled to the main body and held by an operator. The blade is coupled to the main body by being separated therefrom to have a predetermined cutting depth. Also, the main body and the cover may be formed in a single body. [0008] In the meantime, soft tissue cut including the outer surface of a particular portion in the oral cavity may be used as the soft tissue to be transplanted in a portion having a thin thickness or in a place where gum is lost. However, it is advantageous to use soft tissue arranged at a predetermined depth under the outer surface of the particular portion in the oral cavity because of a high transplantation success rate. [0009] Since the conventional dental instrument for cutting soft tissue is equipped with a single blade having a predetermined cutting depth, to cut soft tissue arranged at a predetermined depth under the outer surface of the particular portion in the oral cavity, soft tissue is primarily cut by a predetermined depth under the outer surface and secondarily soft tissue by a desired thickness is cut off from the portion where the outer surface is removed. [0010] In addition, the cutting depth of a blade installed at a dental instrument for cutting soft tissue used for the first cutting process is different from that of a blade installed at a dental instrument for cutting soft tissue used for the second cutting process. Thus, two or more dental instruments for cutting soft tissue are needed for cutting soft tissue. Furthermore, when a single dental instrument for cutting soft tissue is in use, it is inconvenient to replace the blade for each process. DETAILED DESCRIPTION OF THE INVENTION Technical Problem [0011] The inventive concept provides a dental instrument for cutting soft tissue which may easily and simply cut soft tissue arranged at a predetermined depth under the outer surface in the oral cavity so that a soft tissue transplantation surgery may be facilitated. Advantageous Effects [0012] According to the present inventive concept, since the dental instrument for cutting soft tissue employs a dual blade structure of the first and second blades having different cutting depths, the soft tissue arranged at a predetermined depth under the outer surface in the oral cavity may be easily and simply cut so that a soft tissue transplantation surgery may be facilitated. BRIEF DESCRIPTION OF THE DRAWINGS [0013] FIG. 1 illustrates the structure of a plasma processing apparatus according to an embodiment of the present invention; [0014] FIG. 2 is a perspective view of a gate value of FIG. 1 ; [0015] FIG. 3 is a partially cut perspective view of the gate valve taken along line III-III of FIG. 2 ; [0016] FIG. 4 is a perspective view of a cylinder of FIG. 2 during a normal operation; [0017] FIG. 5 is a perspective view of a cylinder of FIG. 2 during a maintenance and repair operation; and [0018] FIG. 6 is a perspective view of a locking pin of FIG. 4 BEST MODE FOR CARRYING OUT THE INVENTION [0019] According to an aspect of the inventive concept, there is provided a dental instrument for cutting soft tissue, which includes a main body in which an inlet hole through which cut soft tissue is input is formed, a blade provided at the main body, at least a portion of the blade being exposed to the outside through the inlet hole, and a cover covering an upper portion of the main body, wherein the blade includes a first blade having a first cutting depth, and a second blade provided adjacent to the first blade and having a second cutting depth smaller than the first cutting depth. [0020] The second blade may be arranged in front of the first blade with respect to a cutting direction. [0021] Each of the first and second blades may include a cutting portion where a blade surface is formed and exposed to the outside through the inlet hole, and a pair of wing portions bent and extending from both ends of the cutting portion and supported by the main body in the main body. [0022] To fix the position of the blade in the main body, a position fixing hole may be formed in each of the wing portions and a position fixing protrusion inserted in the position fixing hole may be formed in the main body. [0023] A position fixing recess engaged with the position fixing protrusion may be formed in the cover. [0024] An exhaust hole through which soft tissue input through the inlet hole is exhausted may be formed in the cover. [0025] A guide wall extending toward the inlet hole may be provided at a position adjacent to the exhaust hole to guide the soft tissue input through the inlet hole to the exhaust hole. [0026] The guide wall may be inclined with respect to a center line of the exhaust hole. [0027] A blade installation portion recessively formed in an area including the inlet hole may be provided at the main body, and a protruding portion protruding from an area including the exhaust hole to be engaged with the blade installation portion may be provided at the cover. [0028] The first and second blades may be either separately or integrally formed. [0029] The blade may be manufactured separately from the main body and coupled to the main body. [0030] The blade may be formed of metal and the main body is formed of plastic, and the blade may be integrally formed at the main body by injection molding. MODE FOR CARRYING OUT THE INVENTION [0031] The attached drawings for illustrating embodiments of the inventive concept are referred to in order to gain a sufficient understanding of the inventive concept and the merits thereof. [0032] Hereinafter, the inventive concept will be described in detail by explaining embodiments of the inventive concept with reference to the attached drawings. Like reference numerals in the drawings denote like elements. [0033] FIG. 1 is a perspective view of a dental instrument for cutting soft tissue according to an exemplary embodiment of the present inventive concept. FIG. 2 is an exploded perspective view of the dental instrument for cutting soft tissue of FIG. 1 . FIG. 3 is a rear perspective view of the cover of FIG. 2 . FIG. 4 is an enlarged perspective view of the blade of FIG. 2 . FIG. 5 is a side view illustrating a portion of the dental instrument for cutting soft tissue of FIG. 1 . FIG. 6 is a plan view of the dental instrument for cutting soft tissue of FIG. 1 . [0034] Referring to FIGS. 1 and 2 , a dental instrument 100 for cutting soft tissue (hereinafter, referred to as the dental instrument) according to an exemplary embodiment of the present inventive concept is a dental instrument for cutting soft tissue in the oral cavity, mainly, the soft tissue of the palate, to provide soft tissue used for a soft tissue transplantation surgery. The dental instrument 100 may include a main body 110 having blades 140 and 150 for cutting soft tissue in the oral cavity, a cover 120 covering the upper portion of the main body 110 , and a handle 130 extending long from the main body 110 to be held by an operator. [0035] In the present exemplary embodiment, the main body 110 , the cover 120 , and the handle 130 are formed of plastic that may be injection molded in consideration of manufacturing convenience and lightness. However, the material of the main body 110 , the cover 120 , and the handle 130 of the dental instrument according to the present inventive concept is not limited to plastic and other material such as metal may be used therefor. [0036] Referring to FIGS. 1-6 , an inlet hole 112 for guiding soft tissue cut by the blades 140 and 150 is formed in the main body 110 of the dental instrument 100 . A blade installation portion 114 in which the blades 140 and 150 are installed is recessively formed in an area including the inlet hole 112 . The blades 140 and 150 are installed at the blade installation portion 114 such that the center portions of the blades 140 and 150 may be exposed to the outside through the inlet hole 112 . [0037] The cover 120 of the dental instrument 100 is coupled to the main body 110 to cover the upper portion of the main body 110 . An exhaust hole 122 through which soft tissue input through the inlet hole 112 of the main body 110 is exhausted is formed in the cover 120 . In the present exemplary embodiment, the cover 120 is coupled to the main body 110 in a forced fit. To this end, a hook groove 126 formed at the leading end of the cover 120 is engaged with a hook step 116 formed at the leading end of the main body 110 . Also, a pair of insertion holes 128 in which a pair of insertion protrusions 118 formed at the rear end of the main body 110 are inserted are provided at the rear end of the cover 120 . An adhesive may be coated between the lower surface of the cover 120 and the upper surface of the main body 110 for a more firm coupling therebetween. [0038] However, in the present inventive concept, the coupling method between the cover 120 and the main body 110 is not limited to the above description and a variety of methods may be adopted instead. For example, the cover 120 may be hinge coupled to the main body 110 to open or close the upper portion of the main body 110 . In this case, the exhaust hole 122 through which soft tissue input through the inlet hole 112 of the main body 110 is exhausted may be omitted. [0039] That is, when the cover 120 is coupled to the main body 110 to open and close the upper portion of the main body 110 , a space defined by the main body 110 and the cover 120 may accommodate the cut soft tissue. Accordingly, even when the exhaust hole 122 is not formed in the cover 120 , the cut soft tissue may be taken out by opening the cover 120 . In addition, the cover 120 and the main body 110 may be integrally manufactured by injection molding. [0040] A protruding portion 124 protrudes from an area including the exhaust hole 122 to be engaged with the blade installation portion 114 of the main body 110 , as illustrated in FIGS. 2 and 3 . The protruding portion 124 of the cover 120 fixes the blades 140 and 150 by pressing both ends of the blades 140 and 150 installed at the blade installation portion 114 . Accordingly, the blades 140 and 150 may be stably fixed in the main body 110 so that movements particularly in upward and downward directions may be prevented. [0041] Also, a guide wall 129 is provided at the lower surface of the cover 120 by extending from a position adjacent to the leading end of the exhaust hole 122 toward the inlet hole 112 of the main body 110 , as illustrated in FIGS. 3 and 6 . The guide wall 129 guides the soft tissue input through the inlet hole 112 . The guide wall 129 is inclined with respect to the center line of the exhaust hole 122 , as illustrated in FIG. 3 . This is to facilitate the delivery of the cut soft tissue input through the inlet hole 112 to the exhaust hole 122 . Also, the guide wall 129 extends toward a position adjacent to the blades 140 and 150 exposed to the outside through the inlet hole 112 . This is to prevent the input of the soft tissue cut by the blades 140 and 150 through the inlet hole 112 and the escape of the soft tissue between the blades 140 and 150 and the lower surface of the main body 110 . [0042] Referring to FIGS. 1 and 2 , the handle 130 of the dental instrument 100 is a portion held by an operator during the cutting of the soft tissue in the oral cavity. The handle 130 is formed of the same plastic material as that used for the main body 110 and integrally formed with the main body 110 . In the present inventive concept, however, the handle 130 may be coupled to the main body 110 to be detachable in a screw coupling method, unlike the present exemplary embodiment. [0043] Referring to FIGS. 2-5 , the blades 140 and 150 installed at the main body 110 have a dual blade structure including the first blade 140 and the second blade 150 arranged adjacent to the first blade 140 . Both of the first and second blades 140 and 150 are formed of metal. The second blade 150 is arranged in front of the first blade 140 with respect to a cutting direction along an arrow of FIG. 5 . That is, with respect to the leading end of the main body 110 , the second blade 150 is arranged behind the first blade 140 . [0044] The first and second blades 140 and 150 respectively include cutting portions 142 and 152 exposed to the outside through the inlet hole 112 and having blade surfaces 141 and 151 , and a pair of wing portions 144 and 154 bent and extending from both ends of the butting portions 142 and 152 and supported by the blade installation portion 114 in the main body 110 . [0045] The cutting portions 142 and 152 are portions where the blade surfaces 141 and 151 are formed with respect to the cutting direction and have a shape of “␣” to be exposed to the outside through the inlet hole 112 . Also, the wing portions 144 and 154 are coupled to the main body 110 and horizontally bent and extending from both ends of the cutting portions 142 and 152 that are vertical to the lower surface of the main body 110 . The wing portions 144 and 154 are placed and supported on the blade installation portion 114 by being inserted in the main body 110 via the inlet hole 112 . The wing portions 144 and 154 placed and supported on the blade installation portion 114 are pressed and fixed by the protruding portion 124 of the cover 120 as described above. The blade surfaces 141 and 151 are inclined at a predetermined angle with respect to the cutting direction, as illustrated in FIG. 3 . This is to improve the cutting performance of the blade surfaces 141 and 151 . [0046] The first and second blades 140 and 150 having the above-described structure have a dual blade structure having different cutting depths H 1 and H 2 . That is, the cutting portion 142 of the first blade 140 is exposed to the outside through the inlet hole 112 so that the first blade 140 may have the first cutting depth H 1 . The cutting portion 152 of the second blade 150 is exposed to the outside through the inlet hole 112 so that the second blade 150 may have the second cutting depth H 2 . The cutting depth denotes a distance from the lower surface of the main body 110 to the blade surface 141 or 151 , which determines the thickness of the soft tissue cut during the soft tissue cutting. [0047] As described above, the soft tissue transplantation surgery in the dental field denotes a surgery of cutting a desired amount of soft tissue off from a particular portion, mainly, the palate, in the oral cavity, and transplant the cut soft tissue in a gum, when the thickness of a gum around a portion where an implant is placed is thin or the gum is insufficient. Although the cut soft tissue including the outer surface of the particular portion in the oral cavity may be used as soft tissue to be transplanted in the gum that is thin or lost, soft tissue arranged at a predetermined depth under the outer surface of the particular portion in the oral cavity is used because of its high transplantation success rate. [0048] However, since a conventional dental instrument for cutting soft tissue is equipped with a single blade having a predetermined cutting depth, to cut soft tissue arranged at a predetermined depth under the outer surface of the particular portion in the oral cavity, soft tissue at a predetermined depth under the outer surface is primarily cut and secondly soft tissue of a desired thickness is cut off from a portion where the outer surface is removed. These processes are inconvenient. [0049] Also, since the cutting depths of a blade installed at a dental instrument used for the first cutting process and a blade installed at a dental instrument used for the second cutting process are different from each other, two or more dental instruments are needed for cutting the soft tissues in the soft tissue cutting processes. Furthermore, when a single dental instrument is used to cut soft tissue, it is inconvenient to replace the blade for each process. [0050] To solve the above inconvenience generated when the conventional dental instrument is in use, the dental instrument 100 according to the present exemplary embodiment has a dual blade structure of the first blade 140 and the second blade 150 having the different cutting depths H 1 and H 2 so that the soft tissue transplantation surgery may be facilitated. [0051] That is, in the dental instrument 100 according to the present exemplary embodiment, since the second blade 150 having the cutting depth H 2 smaller than the cutting depth H 1 of the first blade 140 is arranged in front of the first blade 140 with respect to the cutting direction, the soft tissue arranged at a predetermined depth under the outer surface of the particular portion in the oral cavity may be cut in a single cutting process. [0052] In detail, when an operator cuts soft tissue off from the particular portion in the oral cavity using the dental instrument 100 according to the present exemplary embodiment, the soft tissue is cut by the first blade 140 to a thickness corresponding to the second cutting depth H 2 off from the outer surface of the particular portion. The upper and lower surfaces of the soft tissue arranged at a predetermined depth under the outer surface of the particular portion are respectively cut by the second blade 150 and the first blade 140 so that the cut soft tissue is input between the first and second blades 140 and 150 . [0053] Accordingly, when soft tissue is cut off from the particular portion in the oral cavity by using the dental instrument 100 according to the present exemplary embodiment, the soft tissue arranged at a predetermined depth under the outer surface of the particular portion in the oral cavity may be cut by using a dental instrument equipped with blades having different cutting depths or by not replacing the blade. [0054] The first and second blades 140 and 150 may be installed separately, but close to each other, at the blade installation portion 114 of the main body 110 . Alternatively, the first and second blades 140 and 150 may be integrally formed and installed at the blade installation portion 114 of the main body 110 . The first and second blades 140 and 150 may be manufactured by performing cutting and bending processes to a blade having a long plate shape. In terms of manufacturing convenience, the first and second blades 140 and 150 may be separately formed. In terms of assembly convenience and stability, the first and second blades 140 and 150 may be integrally formed. Also, when the first and second blades 140 and 150 are separately formed, the first and second blades 140 and 150 are installed at the main body 110 by being in contact with each other or slightly separated from each other. [0055] Also, as described above, the positions of the first and second blades 140 and 150 may be fixed in the main body 110 as the blade installation portion 114 recessively formed in the main body 110 and the protruding portion 124 protruding from the cover 120 are pressed to contact each other with the wing portions 144 and 154 of the first and second blades 140 and 150 interposed therebetween. For more firm position fixing, in the present exemplary embodiment, position fixing holes 145 and 155 are formed in the wing portions 144 and 154 of the first and second blades 140 and 150 and position fixing protrusions 115 inserted in the position fixing holes 145 and 155 are formed on the blade installation portion 114 of the main body 110 . Also, position fixing recesses 125 engaged with the position fixing protrusions 115 are formed in the protruding portion 124 of the cover 120 . [0056] In the present exemplary embodiment in which the first and second blades 140 and 150 are separately formed, the position fixing holes 145 and 155 are respectively formed at the first and second blades 140 and 150 . Accordingly, the position fixing protrusions 115 and the position fixing recesses 125 are respectively formed at four positions of each of the blade installation portion 114 and the protruding portion 124 . In the present inventive concept, the shape, position, and number of the position fixing protrusions and the position fixing holes are not limited to the above descriptions. [0057] Accordingly, the positions of the first and second blades 140 and 150 are stably fixed in the main body 110 . In particular, the first and second blades 140 and 150 may be prevented from being twisted at the fixed positions during the cutting of soft tissue. In addition, according to the above-described blade position fixing structure according to the present exemplary embodiment, the determination of the positions of the first and second blades 140 and 150 in the process of assembling the first and second blades 140 and 150 and the cover 120 to the main body 110 is made easy so that assembly convenience may be improved. [0058] Also, in the present exemplary embodiment, the first and second blades 140 and 150 formed of metal are manufactured separately from the main body 110 formed of plastic. However, the first and second blades 140 and 150 formed of metal may be integrally formed by injection molding with the main body 110 formed of plastic. That is, the coupling method of the first and second blades 140 and 150 and the main body 110 is not limited to the above-described method. [0059] As described above, according to the present inventive concept, since the dental instrument for cutting soft tissue employs a dual blade structure of the first and second blades having different cutting depths, the soft tissue arranged at a predetermined depth under the outer surface in the oral cavity may be easily and simply cut so that a soft tissue transplantation surgery may be facilitated. [0060] While the inventive concept has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood that various changes in form and details may be made therein without departing from the spirit and scope of the following claims. INDUSTRIAL APPLICABILITY [0061] The present inventive concept can be applied to the technical field of a dental instrument for cutting soft tissue in the oral cavity.

Disclosed is a dental instrument for cutting soft tissue. The dental instrument for cutting soft tissue according to the present invention includes: a main body having an inlet portion for inserting soft tissue to be cut into the main body; a cutter blade arranged in the main body such that at least a part of the cutter blade is exposed outwardly through the inlet portion; and a lid for covering the upper portion of the main body. The cutter blade includes a first cutter blade having a first cut depth, and a second cutter blade arranged in the vicinity of the first cutter blade, and which has a second cut depth shallower than the first cut depth. The dental instrument of the present invention makes it possible to cut the soft tissue in the deep part of a mouth in an easy and simple process, thereby improving the convenience of soft tissue implantation.

PRIORITY This application claims priority from co-pending provisional U.S. Patent Application Ser. No. 60/147,668, filed Aug. 6, 1999, entitled “GRAPHICS WORKSTATION” and bearing, the disclosure of which is incorporated herein, in its entirety, by reference and co-pending provisional U.S. Patent Application Ser. No. 60/147,609, filed Aug. 6, 1999, entitled “DATA PACKER FOR GRAPHICAL WORKSTATION” and bearing, the disclosure of which is incorporated herein, in its entirety, by reference. CROSS REFERENCE TO RELATED APPLICATIONS This application is related to U.S. patent application Ser. No. 09/632,662, filed on even date herewith, entitled “SYSTEM AND METHOD FOR PRE-PROCESSING A VIDEO SIGNAL” and, naming Jeff S. Ford and David J. Stradley as inventors, the disclosure of which is incorporated herein, in its entirety, by reference, U.S. patent application Ser. No. 09/632,452, filed on even date herewith, entitled “SYSTEM AND METHOD FOR PRODUCING A VIDEO SIGNAL” and, naming Jeff S. Ford and Claude Denton as inventors, the disclosure of which is incorporated herein, in its entirety, by reference, U.S. patent application Ser. No. 09/632,605, filed on even date herewith, entitled “VIDEO CARD WITH INTERCHANGEABLE CONNECTOR MODULE” and, naming Jeff S. Ford and Jeff Belote as inventors, the disclosure of which is incorporated herein, in its entirety, by reference, U.S. patent application Ser. No. 09/632,443, filed on even date herewith, entitled “SYSTEM AND METHOD FOR FRAME RATE MATCHING” and, naming Jeff S. Ford as inventor, the disclosure of which is incorporated herein, in its entirety, by reference, and U.S. patent application Ser. No. 09/632,451, filed on even date herewith, entitled “SYSTEM AND METHOD FOR PACKING AND UNPACKING VIDEO DATA” and, naming Jeff S. Ford, Arthur McKinney and Craig Jordan as inventors, the disclosure of which is incorporated herein, in its entirety, by reference. FIELD OF THE INVENTION The invention generally relates to a video graphics workstation and, more particularly, the invention relates to the pre-processing of a video signal and the production of a video signal. BACKGROUND OF THE INVENTION In general, a video graphics workstation is a system of hardware and software that allows a user to process a video signal for use in a number of different applications. For example, the user may process a video signal for display on a computer monitor, for storage on a computer-readable storage medium, for display on a television, or for storage on a video tape. Typically, however, video graphics workstations are designed to process particular video signals. Thus, most video graphics workstations are not scalable. In other words, most video graphics workstations are not designed to adapt to the changing needs of the workstation's user. SUMMARY OF THE INVENTION In accordance with one aspect of the invention, a workstation for processing and producing video signals comprises a video input system and a video graphics processor. The video input system comprises a video input module, a first video pipeline, and a second video pipeline. The video input module receives and forwards one or more live video signals, producing a forwarded video signal for each received live video signal. The first video pipeline pre-processes VS 1 , wherein VS 1 is a first stored video signal or one of the forwarded video signals produced in the video input module, producing a first pre-processed video signal. The second video pipeline pre-processes VS 2 , wherein VS 2 is the same video signal being pre-processed in the first video pipeline, one of the other forwarded video signals produced in the video input module or a second stored video signal, producing a second pre-processed video signal. The video graphics processor processes VS 3 , wherein VS 3 is a third stored video signal, the first pre-processed video signal, or the second pre-processed video signal, producing a processed video signal. In a further embodiment of the invention, the workstation may further comprise a video output system, the video output system producing a formatted video signal. The video output system may further comprise a receiver for receiving VS 4 , wherein VS 4 is the first pre-processed video signal, the second pre-processed video signal, or the processed video signal, a video pipeline for post-processing VS 4 , the video pipeline operating in conjunction with the video graphics processor and producing a post-processed video signal, and a video output module for converting the post-processed video signal, the video output module producing the formatted video signal. In accordance with another aspect of the invention, a workstation for processing and producing video signals comprises a video graphics processor for processing a video signal, the video graphics processor producing a processed video signal, and a video output system. The video output system comprises a receiver for receiving the processed video signal, a video pipeline for post-processing the processed video signal, the video pipeline producing a post-processed video signal, and a video output module for converting the post-processed video signal, the video output module producing a formatted video signal. In accordance with still another aspect of the invention, a workstation for processing and producing video signals comprises a video graphics processor for processing a video signal, the video graphics processor producing a processed video signal, and a video output system. The video output system comprises a video processing module for post-processing the processed video signal, the video processing module producing a post-processed video signal and having a connector for coupling a video output module, and a video output module for converting the post-processed video signal, the video output module having a specific configuration and producing a formatted video signal, the specific configuration of the video output module setting the characteristics of the video processing module. In a further embodiment of the invention, the video output module may further comprise a buffer for storing the post-processed video signal, a processor for converting the post-processed video signal into the formatted video signal, and a transmitter for transmitting the formatted video signal. In accordance with yet another aspect of the invention, a workstation for processing and producing a video signal comprises a video input system and a video graphics processor. The video input system comprises a video input module for converting a live video signal, the video input module having a specific configuration and producing a formatted video signal, and a video processing module for pre-processing the formatted video signal, the video processing module producing a pre-processed video signal, the video processing module having a connector for coupling the video input module, the specific configuration of the video input module setting the characteristics of the video processing module. The video graphics processor processes the pre-processed video signal, producing, a processed video signal. In a further embodiment of the invention, the video input module may further comprise a first receiver for receiving the live video signal, a processor for converting the live video signal into the formatted video signal, and a buffer for storing the formatted video signal. In accordance with still yet another aspect of the invention, a workstation for processing and producing a video signal comprises a video input system and a video output system. In one embodiment of the invention, the video input system comprises a video input module for receiving and forwarding one or more live video signals, the video input module producing a forwarded video signal for each received live video signal, a first video pipeline for pre-processing VS 1 , wherein VS 1 is a first stored video signal or one of the forwarded video signals produced in the video input module, the first video pipeline producing a first pre-processed video signal, and a second video pipeline for pre-processing VS 2 , wherein VS 2 is the same video signal being pre-processed in the first video pipeline, one of the other forwarded video signals produced in the video input module, or a second stored video signal, the second video pipeline producing a second pre-processed video signal. In this embodiment, the video-output-system comprises a receiver for receiving VS 3 , wherein VS 3 is a third stored video signal, the first pre-processed video signal, or the second pre-processed video signal, a video pipeline for post-processing VS 3 , the video pipeline producing a post-processed video signal, and a video output module for converting the post-processed video signal, the video output module producing a formatted video signal. In another embodiment of the invention, the video input system comprises a video input module for converting a live video signal, the video input module having a specific configuration and producing a formatted video signal, and a video processing module for pre-processing the formatted video signal, the video processing module producing a pre-processed video signal, the video processing module having a connector for coupling the video input module, the specific configuration of the video input module setting the characteristics of the video processing module. In this embodiment, the video output system comprises a video processing module for post-processing the pre-processed video signal, the video processing module producing a post-processed video signal and having a connector for coupling a video output module, and a video output module for converting the post-processed video signal, the video output module having a specific configuration and producing-a formatted video signal, the specific configuration of the video output module setting the characteristics of the video processing module. In alternate embodiments for all aspects of the invention, the video input system may include an ancillary data extractor for removing ancillary data from at least one of the live video signals, and the video output system may include an ancillary data injector for inserting ancillary data into the post-processed video signal. The video output system may also include a generator locking device. In other alternate embodiments for all aspects of the invention, the live video signal may be an analog composite video signal, an analog component video signal, a serial digital composite video signal, a serial digital component video signal, a parallel digital composite video signal, or a parallel digital component video signal. Further, the pre-processed video signal may be an RGB encoded video signal, an RGBA encoded video signal, a YUV-Type encoded video signal, or a YUVA-Type encoded video signal. In addition, the formatted video signal may be an analog composite video signal, an analog component video signal, a serial digital composite video signal, a serial digital component video signal, a parallel digital composite video signal, or a parallel digital component video signal. In still other, alternate embodiments for all aspects of the invention, the process of pre-processing may include changing the sample rate of the video signal being pre-processed, gamma removal, gamma insertion, color space conversion, dithering, and scaling. In addition, the process of pre-processing may include addressing on a frame-by-frame basis the video signal being pre-processed. Further, the video input system may be a Peripheral Component Interconnect circuit board. In-yet other alternate embodiments for all aspects of the invention, the process of post-processing may include region of interest selection, frame rate matching, scaling, framing, letter boxing, changing the sample rate of the video signal being post-processed, gamma removal, gamma insertion, color space conversion, and changing frames of video data into interleaved fields of video data. In addition, the process of post-processing may include addressing on a frame-by-frame basis the video signal being pre-processed. Further, the video output system may be a Peripheral Component Interconnect circuit board. BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other objects and advantages of the invention will be appreciated more fully from the following further description thereof with reference to the accompanying drawings wherein: FIG. 1 shows a block diagram of an exemplary video graphics workstation for implementing the various embodiments of the invention. FIGS. 2 a through 2 b show various exemplary embodiments for a video input system for use in a video graphics workstation. FIG. 3 shows an exemplary embodiment for a scalable video input system for use in a video graphics workstation. FIGS. 4 a and 4 b show various exemplary exploded views for mounting an interchangeable connector module to a video processing module. FIG. 5 shows an exemplary embodiment for a video output system for use in a video graphics workstation. FIG. 6 shows an exemplary embodiment for a scalable video output system for use in a video graphics workstation. FIG. 7 shows an exemplary video graphics workstation for carrying out various exemplary video graphics applications. FIG. 8 shows an exemplary process in a video graphics workstation for video signal frame rate matching. FIGS. 9 a and 9 b show an exemplary process in a video graphics workstation for packing and unpacking pixels. DETAILED DESCRIPTION OF THE INVENTION In accordance with one embodiment of the invention, a video graphics workstation includes three sub-systems—a video input system, a video graphics processor, and a video output system. In general, the video input system pre-processes video signals, the video graphics processor processes and/or displays video signals and graphics input, and the video output system produces video signals. The video signals processed and produced may be analog video signals or digital video signals. FIG. 1 shows a block diagram of an exemplary video graphics workstation for implementing the various embodiments of the invention. Video graphics workstation 100 includes central processing unit 102 , chipset 104 , memory 106 , two Peripheral Component Interconnect (“PCI”) buses—a 64-bit PCI bus and a 32-bit PCI bus, and an Accelerated Graphics Port (“AGP”). Video input system 110 and storage medium 120 connect to chipset 104 via the 64-bit PCI bus. Video graphics processor 130 connects to chipset 104 via the AGP. Video output system 140 connects to chipset 104 via the 32-bit PCI bus. In addition, video input system 110 connects to video graphics processor 130 via local bus 182 and video output system 140 connects to video graphics processor 130 via local bus 184 . A. Video Input System FIGS. 2 a through 2 b show various exemplary embodiments for video input system 110 . In particular, FIG. 2 a shows an exemplary embodiment for pre-processing a live video signal in video input system 110 . The process of pre-processing a video signal includes, among other things, up sampling, down sampling, gamma insertion, gamma removal, color space conversion, scaling and dithering. For purposes of understanding and reference, and without intending to limit the meaning the above-identified processes have to a person of ordinary skill in the art, listed below are definitions for the above-identified processes: PROCESS DEFINITION Up Sampling Process of increasing the amount of digital data used to represent an image Down Sampling Process of decreasing the amount of digital data used to represent an image Gamma Insertion Process of inserting a value to compensate for the non-linear characteristics of an output device (e.g., a computer monitor) Gamma Removal Process of removing a value inserted to compensate for the non-linear characteristics of an output device (e.g., a computer monitor) Color Space Process of converting between Conversion different color encoding schemes (e.g., between a component color scheme and a composite color scheme) Scaling Process of changing the resolution of an image Dithering Process of combining colors to trick the eye into seeing more colors than the system can actually display In addition, pre-processing may include addressing on a frame-by-frame basis the video signal being pre-processed. In video, a frame is a single complete image. In frame-by-frame addressing, video input system 110 may pre-process one frame of a video signal different than, for example, the next frame of the video signal. In the embodiment shown in FIG. 2 a , video input system 110 includes video input module 200 , input multiplexer 212 , input multiplexer 222 , pipeline 210 , pipeline 220 , output multiplexer 214 , and output multiplexer 224 . Video input module 200 receives a live video signal and forwards the live video signal to, for example, a buffer (not shown) for transfer to pipeline 210 and/or pipeline 220 . The live video signal may be an analog video signal or a digital video signal. If the live video signal is an analog video signal, then video input module 200 converts the live video signal into a computer-readable format. The input multiplexers, multiplexer 212 and multiplexer 222 , route the respective video signal to the pipelines. In particular, multiplexer 212 routes video signals to pipeline 210 and multiplexer 222 routes video signals to pipeline 220 . The pipelines, pipeline 210 and pipeline 220 , pre-process the forwarded video signal. The output multiplexers, multiplexer 214 and multiplexer 224 , route the pre-processed video signals to, for example, various output buffers (not shown) accessible to video graphics workstation 100 . For example, the pre-processed video signal may be forwarded, via the 64-bit PCI bus and the AGP, to video graphics processor 130 . Or, the pre-processed video signal may be forwarded, via the 64-bit PCI bus and the 32-bit PCI bus, to video output system 140 . The pre-processed video signal may also be forwarded, via the 64-bit bus, to storage medium 120 . FIG. 2 b shows an exemplary embodiment for pre-processing a live video signal and a stored video signal in video input system 110 . In this embodiment, pipeline 210 and pipeline 220 pre-process a live video signal and/or a stored video signal. Typically, the stored video signal is forwarded from, for example, storage medium 120 , to a buffer (not shown) to allow for efficient transfer of the stored video signal to video input system 110 . With two pipelines, a single live, or stored, video signal may reach pipeline 210 and pipeline 220 . Thus, two versions of a single live, or stored, video signal may be generated at the same time. For example, video input system 110 may receive a television signal and pre-process the televison signal via pipeline 210 for display on a computer monitor and via pipeline 220 for storage on storage medium 120 . In addition, using frame-by-frame addressing, video input system 110 may pre-process more than two video signals substantially at the same time. In this embodiment, the frames of the different video signals are interleaved and routed to pipeline 210 and pipeline 220 . Moreover, video input system 110 may pass a video signal, either live or stored, through pipeline 210 and/or pipeline 220 without pre-processing the video signal. In a further embodiment of video input system 110 , video input module 200 receives and forwards more than one live video signal to, for example, a buffer (not shown) for transfer to pipeline 210 and/or pipeline 220 . The live video signals may be analog video signals or digital video signals. If the live video signal is an analog video signal, then video input module 200 converts the live video signal into a computer-readable format. For each received live video signal, video input module 200 produces a forwarded video signal. In a further embodiment of these exemplary embodiments, video input module 200 includes an ancillary data extractor for removing ancillary data from a live video signal. Typically, the ancillary data is removed from the live video signal prior to receipt of the live video signal in the input multiplexers, multiplexer 212 and multiplexer 214 . Ancillary data includes, among other things, audio data and close captioning data. FIG. 3 shows an exemplary embodiment for a scalable video input system 110 . In this embodiment, video input system 110 includes video input module 300 and video processing module 350 . Video input module 300 includes receiver 302 , processor 304 , and buffer 306 . Receiver 302 receives a live video signal and forwards the live video signal to processor 304 . Processor 304 converts the received video signal into a video signal having a common video data format. The formatted video signal is then forwarded to buffer 306 for transfer to video processing module 350 . In alternate embodiments of the invention, video input module 300 may include an ancillary data extractor for removing ancillary data from a live video signal. Video processing module 350 includes input multiplexer 352 , pipeline 354 , and output multiplexer 356 . As discussed above in regard to the embodiments shown in FIG. 2 , video processing module 350 pre-processes the formatted video signal and/or a stored video signal and routes the pre-processed video signal to, for example, a buffer (not shown) accessible to video graphics workstation 100 . Video processing module 350 may have two pre-processing pipelines. In addition, the pre-processed video signal may be forwarded to video graphics processor 130 , video output system 140 , and/or storage medium 120 . The common video data format may be an organized bit stream. As noted above, a frame is a single complete image. An image, in turn, is composed of a raster of picture elements, referred to as pixels. A pixel is represented by some number of bits stored, for example, in memory. Pixels are the smallest “units” on a screen that can be given a color (represented with color data) and an opacity (represented with alpha data). Thus, an organized bit stream may include color data, alpha data, or color data and alpha data. For example, a bit stream with color data may include 20-bits for color data. In contrast, a bit stream for alpha data may include 10-bits for alpha data. Pipeline 354 may pre-process color data separate from alpha data. In this embodiment, a color data bit stream may be forwarded on a output different from the output used to forward alpha data. In these exemplary embodiments, video input module 300 and video processing module 350 are separate modules coupled together via, for example, male/female cables. In one embodiment, video input module 300 is a daughterboard that plugs into video processing module 350 . The separation of the various functions of a video input system into a video input module and a video processing module allows for the separation of video input module 300 and video processing module 350 . In turn, the separation of video input module 300 from video processing module 350 allows for the configuration of various video input modules, each configured to receive and process different video signal formats. Because the “input” functions of video input system 110 have been separated from the “processing” functions of video input system 110 , video input module 300 may be “exchanged” without the need to replace video processing module 350 . Thus, when a user wants to input, for example, a serial digital component video signal into video input system 110 instead of an analog composite video signal, the user “exchanges” the video input module configured for the analog composite video signal with a video input module configured for the serial digital component video signal. In turn, processor 304 (on the “new” video input module) signals video processing module 350 of the new configuration. FIGS. 4 a and 4 b show various exemplary exploded views for mounting an interchangeable connector module, such as video input module 300 , to a processing module, such as video processing module 350 . In FIG. 4 a , interchangeable connector module 400 includes connectors 402 and mounting holes 404 . Circuit board 450 includes plate 455 . Plate 455 includes connector holes 452 and mounting holes 454 . Plate assembly 430 includes plate 435 a and two screws (not shown). Plate 435 a includes connector holes 432 a and mounting holes 434 a . Connectors 402 are designed to fit through connector holes 432 and 452 . The two screws, passing through mounting holes 434 a and mounting holes 454 , secure interchangeable connector module 400 to circuit board 450 via mounting holes 404 . In FIG. 4 b , plate assembly 430 further includes plate 435 b and gaskets 436 . Gaskets 436 are designed to improve electromagnetic shielding. For example, gaskets 436 may be composed of a rubber compound with embedded silver. For the exemplary embodiments shown in both FIG. 4 a and FIG. 4 b , in operation, interchangeable connector module 400 would also be coupled (not shown) to processing module 450 . B. Video Graphics Processor Various exemplary embodiments of a video graphics processor are disclosed in the following: 1. U.S. patent application Ser. No. 09/353,495, filed Jul. 15, 1999, and entitled “MULTIPROCESSOR GRAPHICS ACCELERATOR,” the disclosure of which is hereby incorporated, in its entirety, by reference; 2. U.S. patent application Ser. No. 09/354,462, filed Jul. 15, 1999, and entitled “APPARATUS AND METHOD OF DIRECTING GRAPHICAL DATA TO A DISPLAY DEVICE,” the disclosure of which is hereby incorporated, in its entirety, by reference; 3. U.S. patent application Ser. No. 09/353,420, filed Jul. 15, 1999, and entitled “WIDE INSTRUCTION WORD GRAPHICS PROCESSOR,” the disclosure of which is hereby incorporated, in its entirety, by reference; and 4. U.S. patent application Ser. No. 09/353,419, filed Jul. 15, 1999, and entitled “SYSTEM FOR DISPLAYING A TELEVISION SIGNAL ON A COMPUTER MONITOR,” the disclosure of which is hereby incorporated, in its entirety, by reference. C. Video Output System FIG. 5 shows an exemplary embodiment for video output system 140 . In FIG. 5 , video output system 140 includes receiver 500 , pipeline 510 , and video output module 520 . Receiver 500 receives a video signal and forwards the received video signal to, for example, a buffer (not shown) for transfer to pipeline 510 . The received video signal may be formatted in one of many different video data formats. For example, the received video signal may be an RGB encoded video signal or an RGBA encoded video signal. An RGB encoded video signal encodes an image in accordance with the amount of red, green, or blue contained in the image. An RGBA encoded video signal further encodes an image in accordance with the amount of opacity contained in the image. The received video signal may also be a “YUV-Type” encoded video signal or a “YUVA-Type” encoded video signal. A “YUV-Type” encoded video signal encodes an image in accordance with the amount of luma (black and white) and color differences contained in the image. A “YUVA-Type” encoded video signal further encodes an image in accordance with the amount of opacity contained in the image. A “YUV-Type” encoded video signal includes, among other things, a YUV encoded video signal, a YCbCr encoded video signal, and a YPbPr encoded video signal. A “YUVA-Type” encoded video signal includes, among other things, a YUVA encoded video signal, a YCbCrA encoded video signal, and a YPbPrA encoded video signal. Pipeline 510 post-processes the forwarded video signal and forwards the post-processed video signal to video output module 520 . The process of post-processing includes, among other things, region of interest selection, frame rate matching, spatial adaptation, up sampling, down sampling, gamma insertion, gamma removal, and color space conversion. Spatial adaptation includes, among other things, scaling and picture framing. Picture framing includes, among other things, letter boxing. For purposes of understanding and reference, and without intending to limit the meaning the above-identified processes have to a person of ordinary skill in the art, listed below are definitions for the above-identified processes not previously defined: PROCESS DEFINITION Region of Interest Process of selecting a portion of an Selection image for post-processing Frame Rate See Section E. Matching Picture Framing Process of positioning an image on a and Letter Boxing background image In addition, post-processing may include addressing on a frame-by-frame basis the video signal being post-processed. In frame-by-frame addressing, video output system 140 may post-process one frame of a video signal different than, for example, the next frame of the video signal. Also, post-processing may include changing a frame of video data into interlaced fields of video data. In using this process, video output system 140 “blends” single or multiple lines from a frame in an input video signal into a single line in an output video signal, e.g, 3:2 pull-down. Video output module 520 converts the post-processed video signal to a formatted video signal. The formatted video signal may be an analog video signal or a digital video signal. Typically, video output system 140 also includes a generator locking device, referred to as a genlock, which allows the synchronized display of graphics and video. A genlock may lock video output system 140 to, for example, video graphics processor 130 . In addition, regardless of whether video output system 140 is locked to video graphics processor 130 , a genlock may lock video output module 520 to another source, e.g., an external clock, an internal clock, etc. In a further embodiment of these exemplary embodiments, video output module 520 includes an ancillary data injector for inserting ancillary data into the post-processed video signal prior to conversion of the post-processed video signal. As noted above, ancillary data includes, among other things, audio data and close captioning data. FIG. 6 shows an exemplary embodiment for a scalable video output system 140 . In this embodiment, video output system 140 includes video processing module 600 and video output module 650 . Video processing module 600 includes receiver 602 and pipeline 604 . As discussed above in regard to the embodiments shown in FIG. 3 , video processing module 600 receives a video signal, post-processes the received video signal, and forwards the post-processed video signal to video output module 650 . Video processing module 600 may include a generator locking device for locking video processing module 600 to, for example, video graphics processor 130 . Video output module 650 includes buffer 652 , processor 654 , and transmitter 656 . Video processing module 600 forwards the post-processed video signal to buffer 652 for transfer to processor 654 . Processor 654 converts the post-processed video signal into a formatted video signal, e.g., an analog composite video signal, a parallel digital component video signal, etc. The formatted video signal is then forwarded to transmitter 656 . In alternate embodiments of the invention, video output module 650 may include an ancillary data injector for inserting ancillary data into the post-processed video signal. In these exemplary embodiments, video output module 650 and video processing module 600 are separate modules coupled together via, for example, male/female cables. In one embodiment, video output module 650 is a daughterboard that plugs into video processing module 600 . The separation of the various functions of a video output system into a video output module and a video processing module allows for the separation of video output module 650 and video processing module 600 . In turn, the separation of video output module 650 from video processing module 600 allows for the configuration of various video output modules, each configured to process and produce different video signal formats. Because the “output” functions of video output system 140 have been separated from the “processing” functions of video output system 140 , video output module 650 may be “exchanged” without the need to replace video processing module 600 . Thus, when a user wants to output, for example, a serial digital component video signal instead of an analog composite video signal, the user “exchanges” the video output module configured for the analog composite video signal with a video output module configured for the serial digital component video signal. In turn, processor 654 (on the “new” video output module) signals video processing module 600 of the new configuration. As an interchangeable connector module, video output module 650 may be mounted on video processing module 600 , a processing module, in the manner shown in FIGS. 4 a and 4 b. D. Exemplary Video Graphics Applications FIG. 7 shows an exemplary video graphics workstation implementing one embodiment of the invention for carrying out various exemplary video graphics applications In this embodiment, video input system 730 includes two pipelines, pipeline 732 and pipeline 734 . In addition, video output system 750 forwards a formatted video signal to a video tape recorder for recordation. In one application, video graphics workstation 700 captures a live video signal. First, video graphics workstation 700 receives the live video signal. Next, the received video signal is pre-processed in pipeline 732 of video input system 730 . Then, the pre-processed video signal is forwarded, via the 64-bit PCI bus, to storage medium 720 . In another application, video graphics workstation 700 captures and displays a live video signal. First, video graphics workstation 700 receives the live video signal. Next, the received video signal is pre-processed in both pipeline 732 and pipeline 734 of video input system 730 . Then, the pre-processed video signal from pipeline 732 is forwarded, via the 64-bit PCI bus, to storage medium 720 . In the interim, the pre-processed video signal from pipeline 734 is forwarded, via local bus 782 , to video graphics processor 740 for display on computer monitor 760 . The pre-processed video signal from pipeline 734 may also be forwarded to video graphic processor 740 via the 64-bit PCI bus and the AGP. In alternate embodiments, the pre-processed video signal from pipeline 734 may be forwarded, via the 64-bit bus and the 32-bit bus, to video output system 750 for recordation on video tape recorder 770 . In another application, video graphics workstation 700 plays back a stored video signal. First, video graphics workstation 700 forwards a stored video signal, via the 64-bit PCI bus to video input system 730 . Next, the stored video signal is pre-processed in pipeline 732 . Then, the pre-processed video signal is forwarded, via local bus 782 , to video graphics processor 740 for display on computer monitor 760 . In an alternate embodiment, the pre-processed video signal may also be forwarded, via local bus 784 , to video output system 750 for recordation on video tape recorder 770 . In another application, video graphics workstation 700 processes a stored video signal, for example, performs a two-dimensional or three-dimensional effect on the stored video signal, and displays the processed video signal. First, video graphics workstation 700 forwards a stored video signal, via the 64-bit PCI bus, to video input system 730 . Next, the stored video signal is pre-processed in pipeline 732 . Then, the pre-processed video signal is forwarded, via local bus 782 , to video graphics processor 740 for “effects” processing and display on a computer monitor 760 . In an alternate embodiment, the processed video signal may also be forwarded, via local bus 784 , to video output system 750 for recordation on video tape recorder 770 . In another application, video graphics workstation 700 pre-processes a stored video signal and saves the pre-processed video signal. First, video graphics workstation 700 forwards a stored video signal, via the 64-bit PCI bus, to video input system 730 . Next, the stored video signal is pre-processed in pipeline 732 . Then, the pre-processed video signal is forwarded, via the 64-bit PCI bus, to storage medium 720 . In alternate embodiments, the pre-processed video signal may be forwarded, via the 64-bit PCI bus, to central processing unit 715 or to memory 710 . In another application, video graphics workstation 700 processes a stored video signal and saves the processed video signal. First, video graphics workstation 700 forwards a stored video signal, via the 64-bit PCI bus, to video input system 730 . Next, the stored video signal is pre-processed in pipeline 732 . Then, the pre-processed video signal is forwarded, via local bus 782 , to video graphics processor 740 for “effects” processing. Last, the processed video signal is forwarded, via local bus 782 , to video input system 730 . Video input system 730 may pre-process the processed video signal, for example, to convert the processed signal to a format better suited for saving, or forward the processed signal, via the 64-bit PCI bus, to storage medium 720 . In another application, video graphics workstation 700 combines a live video signal, a stored video signal, and graphics information and records the combined video signal. First, video graphics workstation 700 receives a live video signal. Next, the received video signal is pre-processed in pipeline 732 of video input system 730 . In the interim, video graphics workstation 700 forwards a stored video signal to video input system 730 . Next, the stored video signal is pre-processed in pipeline 734 . Then, graphics information (via the AGP), the pre-processed video signal from pipeline 732 (via local bus 782 ), and the pre-processed video signal from pipeline 734 (via local bus 782 ) are forwarded to video graphics processor 740 for “effects” processing. Last, the processed video signal is forwarded, via local bus 784 , to video output system 750 for recordation on video tape recorder 770 . E. Frame Rate Matching As discussed above, a frame is a single complete image. Typically, a frame is represented, in a video graphics workstation, with frame data. In general, frame rate is how fast a new frame of frame data, in other words, an new image, is available for processing or display. The process of frame rate matching includes, among other things, matching the frame rate of, for example, a video signal to the frame rate of, for example, an output device. Typically, in a video graphics workstation, the process of frame rate matching occurs in the video output system. FIG. 8 shows an exemplary process in a video graphics workstation for video signal frame rate matching. The process begins at step 800 , in which the video graphics workstation fills a first buffer with a sequence of frame data. Next, at step 810 , the workstation reads out the frame data in the first buffer and, at substantially the same time, fills a second buffer with the next sequence of frame data. The process continues at step 820 , in which the video graphics workstation determines whether all of the frame data has been read out of the first buffer. If yes, the video graphics workstation fills the first buffer with the next sequence of frame data. If no, the video graphics workstation, at step 830 , fills the third buffer with the next sequence of frame data. Next, at step 840 , the video graphics workstation determines whether all of the frame data in the first buffer has been read out of the first buffer. If no, the video graphics workstation begins to fill the second buffer with the next sequence of frame data. If yes, the video graphics workstation, at step 850 , determines whether the second buffer or the third buffer has the most current and most complete frame data. If the second buffer has the most current and most complete frame data, the video graphics workstation, at step 860 , reads the frame data out of the second buffer. If the third buffer has the most current and most complete frame data, the video graphics workstation, at step 870 , reads the frame data out of the third buffer. In a further embodiment of the invention, the buffer determined not to have been filled with the most current and most complete frame data becomes a remainder buffer. In this embodiment, the video graphics workstation fills the remainder buffer with the next sequence of frame data. Then, if all of the frame data has not been read out of the buffer determined to have been filled with the most current and most complete frame data, the video graphics workstation fills the first buffer with the next sequence of frame data. The video graphics workstation continues to alternate between the remainder buffer and the first buffer until all of the frame data has been read out of the buffer determined to have been filled with the most current and most complete frame data. Thus, in operation, the three buffers change “roles.” For example, the buffer now being filled may, depending upon the circumstances, next become either the buffer being read or the buffer not being either filled or read. Or, the buffer now being read may, depending upon the circumstances, next become either the buffer being filled or the buffer not being either filled or read. Or, the buffer now not being either filled or read may, depending upon the circumstances, next become either the buffer being read or the buffer being filled. In both embodiments of the invention, a buffer may contain the most complete frame data when the buffer is less than 100% full. Typically, however, a buffer contains the most complete frame data when the buffer is 100% full. In addition, a buffer may contain one or more frames of frame data. Typically, however, a buffer contains one frame of frame data. Further, both embodiments of the invention are scalable. In other words, both embodiments of the invention may be used to match any frame rates. For example, a frame rate to be matched may be 24/1.001 frames/second, or 24 frames/second, or 25 frames/second, or 29.97 frames/second, or 30/1.001 frames/second, or 30 frames/second, or 50 frames/second, 60/1.001 frames/second, 60 frames/second or 75 frames/second. Also, the frame rates being matched may be the same frame rate. Or, in the alternative, the frame rates being matched may be multiples of each other. F. Packing and Unpacking Video Data As discussed above, an image is composed of a raster of picture elements, referred to as pixels. Pixels are the smallest “units” on a screen that can be given a color (represented with color data) and an opacity (represented with alpha data). In general, a pixel is represented by some number of bits stored, for example, in memory. For example, a pixel may be 1-bit in length, 8-bits in length, 10-bits in length, 24-bits in length, or 32-bits in length. In turn, memory stores data in segments, with each segment being some number of bits. For example, memory may be capable of storing data in 32-bit segments or 64-bit segments. It may inefficient, however, to store, for example, one 8-bit pixel in a 32-bit memory segment. But, four 8-bit pixels may be “packed” in a 32-bit memory segment. In the same way, four 24-bits pixels may be packed in three 32-bit memory segments. Typically, in a video graphics workstation, the process of packing and unpacking pixels occurs in the video input system. FIGS. 9 a and 9 b show an exemplary process in a video graphics workstation for packing and unpacking pixels. In particular, FIG. 9 a shows an exemplary process in a video graphics workstation for unpacking pixels. The process begins at step 900 a , in which the video graphics workstation loads a shift-down register with the pixel data contained in a first memory device. In this embodiment, the first memory device has a bit storage capacity smaller in size than the bit storage capacity of the shift-down register. For example, the first memory device may be 64-bits in length and the shift-down register may be 80-bits in length. Next, at step 910 a , the video graphics workstation shifts one complete pixel of pixel data down the shift-down register. For example, one 24-bit pixel is shifted down the shift-down register. Then, at step 920 a , the video graphics workstation determines whether the shift-down register contains another complete pixel of pixel data. If yes, the video graphics workstation shifts another complete pixel of pixel data down the shift-down register. If no, the video graphics workstation, at step 930 a , loads a shift-up register with the pixel data contained in a second memory device. In this embodiment, the second memory device is contiguous with the first memory device and has the same bit storage capacity as the first memory device. Also, the shift-up register has the same bit storage capacity as the shift-down register. Next, at step 940 a , the video graphics workstation shifts the pixel data in the shift-up register up the number of bits of pixel data remaining in the shift-down register. For example, if the shift down register has 16 bits of pixel data remaining, then the video graphics workstation shifts the pixel data in the shift-up register up 16 bits. Then, at step 950 a , the video graphics workstation moves the pixel data in the shift-up register to the shift-down register, placing the shifted-up pixel data in the same bit locations in the shift-down register the shifted-up pixel data occupied in the shift-up register. For example, if the shifted-up pixel data occupied bit locations 16 through 63 in the shift-up register, then the video graphics workstation moves the shifted-up pixel data to bit locations 16 through 63 in the shift-down register. FIG. 9 b shows an exemplary process in a video graphics workstation for packing pixels. In this embodiment, the memory device in which the pixel data will be packed has a bit storage capacity smaller in size than the bit storage capacity of the shift-up register. For example, the memory device may be 64-bits in length and the shift-up register may be 80-bits in length. The process begins at step 900 b , in which the video graphics workstation shifts one complete pixel of data up a shift-up register. Next, at step 910 b , the vide graphics workstation determines whether the shift-up register has capacity to hold another complete pixel of pixel data. If yes, the video graphics workstation shifts another complete pixel of pixel data up the shift-up register. If no, the video graphics workstation, at step 920 b , moves the pixel data in the uppermost bit locations of the shift-up register to a shift-down register, placing the moved pixel data in the same bit locations in the shift-down register the moved pixel data occupied in the shift-up register. For example, if the moved pixel data occupied bit locations 16 through 63 in the shift-up register, then the video graphics workstation moves the shifted-up pixel data to bit locations 16 through 63 in the shift-down register. The amount of pixel data moved from the uppermost bit locations in the shift-up register depends upon the bit storage capacity of the memory device in which the pixel data will be packed. For example, if the memory device is 64-bits in length, then the video graphics workstation moves the 64 uppermost bits of the shift-up register to the shift-down register. Also, the shift-down register has the same bit storage capacity as the shift-up register. Next, at step 930 b , the video graphics workstation shifts the pixel data in the shift-down register down the number of bits of pixel data remaining in the shift-up register. For examples, if the shift-up register has 16 bits of pixel data remaining, then the video graphics workstation shifts the pixel data in the shift-down register down 16 bits. Then, at step 940 b , the video graphics workstation moves the contents of the shift-down register to the memory device. In all embodiments of the invention, one complete pixel of pixel data may include a bit stream of color data, a bit stream of alpha data, or a bit stream of color data and alpha data. The color data may be RGB encoded or “YUV-Type” encoded. In addition, the color data and alpha data may be RGBA encoded or “YUVA-Type” encoded. The various embodiments of the invention may be implemented in any conventional computer programming language. For example, the various embodiments may be implemented in a procedural programming language (for example, “C”) or an object-oriented programming language (for example, “C++” or JAVA). The various embodiments of the invention may also be implemented as preprogrammed hardware elements (for example, application specific integrated circuits or digital processors), or other related components. The various embodiments of the invention may be also implemented as a computer program product for use with a computer system. Such implementation may include a series of computer instructions fixed either on a tangible medium, such as a computer readable media (for example, a diskette, CD-ROM, ROM, or fixed disk), or transmittable to a computer system via a modem or other interface device, such as a communications adapter connected to a network over a medium. The medium may be either a tangible medium (for example, optical or analog communications lines) or a medium implemented with wireless techniques (for example, microwave, infrared or other transmission techniques). The series of computer instructions preferably embodies all or part of the functionality previously described herein with respect to the system. Those skilled in the art should appreciate that such computer instructions can be written in a number of programming languages for use with many computer architectures or operating systems. Furthermore, such instructions may be stored in any memory device, such as semiconductor, magnetic, optical or other memory devices, and may be transmitted using any communications technology, such as optical, infrared, microwave, or other transmission technologies. It is expected that such a computer program product may be distributed as a removable medium with accompanying printed or electronic documentation (for example, shrink wrapped software), pre-loaded with a computer system (for example, on system ROM or fixed disk), or distributed from a server or electronic bulletin board over the network (for example, the Internet or World Wide Web). Although various exemplary embodiments of the invention have been disclosed, it should be apparent to those skilled in the art that various changes and modifications can be made which will achieve some of the advantages of the invention without departing from the true scope of the invention. These and other obvious modifications are intended to be covered by the appended claims.

A workstation for processing and producing a video signal comprises a video input system, a video graphics processor, and a video output system. The video input system may comprise a video input module, a first video pipeline, and a second video pipeline. The video output system may comprise a receiver, a video pipeline and a video output module. In addition, the video input system may comprise a video input module having a specific configuration and a video processing module having a connector for coupling the video input module, the specific configuration of the video input module setting the characteristics of the video processing module. The video output system may comprise a video processing module having a connector for coupling a video output module and a video output module having a specific configuration, the specific configuration of the video output module setting the characteristics of the video processing module.

FIELD OF THE INVENTION The invention relates to a surfactant composition, suitable for enhanced oil recovery and to a method for enhancing oil recovery. BACKGROUND OF THE INVENTION It is well known in the art of oil production that only a portion of the oil present in subterranean oil reservoirs can be recovered by direct methods, also called primary recovery techniques. A portion of the oil which is not recoverable by primary recovery techniques, can be recovered by secondary recovery techniques. The latter techniques include the use of a displacement fluid e.g. water, which is injected into the oil reservoir or into the vicinity of the reservoir. If after application of the secondary recovery techniques an appreciable amount of oil is still retained in the reservoir, it is still possible to recover a part of that oil from that reservoir. This oil, in the form of immobile, capillary-trapped droplets, can be mobilized by injection of suitable surfactant solutions; these interact with the oil to form a micro-emulsion that reduces the capillary trapping forces to a very low level. The process is called surfactant flooding. Once mobilized, the oil forms a growing bank that leaves almost no oil behind in the flooded part of the reservoir. Since the oil bank precedes the surfactant bank it is not necessary to inject surfactant continuously throughout the flood. So when a certain volume of surfactant solution has been injected, it may be followed by a cheaper fluid, such as viscous water; and later water alone. The injection of the surfactant, viscous water and water involves the displacement of oil to the production well. The micro-emulsion on its turn is displaced in the direction of the production well by the viscous water. Consequently a number of moving zones and banks is developing in the oil reservoir and as long as the micro-emulsion is intact, oil can be recovered. Surfactants are soaps or soap-like chemicals. Their molecules consist of a hydrophilic part, attracted to water, and a lipophilic part, attracted to oil. Because of this amphiphilic nature, even at small concentrations, they can greatly reduce the interfacial tension between oil and water and form micro-emulsions. It is a problem to recover the oil from deeper reservoirs, since at ever increasing depths the temperature becomes higher and the micro-emulsion breaks down in oil and water, whereby the oil is again trapped in the pores. The micro-emulsions formed by oil, surfactant and water are thus not stable enough to withstand the higher temperatures. It is an object of the invention to find surfactant compositions which are able to form micro-emulsions which are stable at high temperatures as well as at low temperatures and which over a broad temperature range are in equilibrium with their environment and do not deteriorate. SUMMARY OF THE INVENTION The present invention therefore relates to a surfactant composition, suitable for enhanced oil recovery, which comprises: a) a dialkylated benzenesulfonate of the chemical formula ##STR1## wherein M is an alkali metal and R 1 and R 2 are the same or different C 2 -C 20 alkyl groups, and b) a polyalkoxyphenylethersulfonate of the chemical formula ##STR2## wherein M is an alkali metal, R is a C 9 -C 22 -alkyl group and R 3 is a C 1 -C 4 -alkylene group, and n is an integer from 1 to 20, the weight ratio of a:b being in the range of from 60:40 to 10:90. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a phase diagram of a composition according to the invention. FIG. 2 shows the production performance of the waterflood carried out in the example. FIG. 3 shows the production performance of the surfactant flood carried out in the example. DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred compostions are those wherein M is sodium and wherein R 1 and R 2 independently are C 6 -C 14 -alkyl groups. In a more preferred composition according to the invention R is a C 10 -C 18 -alkyl group, R 3 is an ethylene group and n is an integer of from 1 to 5 and the dialkylated benzene sulfonate predominantly contains the two alkyl groups situated in the para position to each other. In a preferred surfactant composition according to the invention, the weight ratio of the dialkylated benzenesulfonate and polyalkoxy phenylethersulfonate lies between 50:50 and 15:85, preferably between 40:60 and 20:80. The surfactant composition may comprise a thickener, e.g. a polysaccharide. The invention further relates to a method of enhancing recovery of oil from a subterranean oil-containing reservoir, which method comprises injecting into the reservoir an aqueous solution of the surfactant composition, displacing said aqueous solution within said subterranean reservoir, and recovering oil from the reservoir. This procedure can be applied after the water-flooding or already in an early stage of the water-flooding, the latter called the surfactant enhanced water-flooding. The surfactant composition according to the invention has an excellent solubility in cold seawater (20° C.) as well as in seawater at reservoir conditions (95° C.). When oil is present, a type III phase behavior or middle phase is generated which is highly active, thus a low interfacial tension between oil and micro-emulsion water exists. The surfactant composition according to the invention is not sensitive to fluctuations in temperature and salinity. In FIG. 1 is disclosed a phase diagram of a composition according to the invention, given on the right leg of the triangle. On its basis is given the volume percentage (gram surfactant per 100 ml water), while the oil/water ratio is 1. Temperature measurements are all at 95° C. As water seawater is taken. The hatched part of the phase diagram includes the compositions which form a micro-emulsion in equilibrium with both water and oil; consequently in the hatched part a 3-phase system exists. Outside the hatched part a one-phase or two-phase system exists. On the top of the triangle is given 100% weight of C 8 -C 10 -dialkylated sodium benzene sulfonate (DABS), while below on the right is given 100% weight of the C 12 -C 15 -alcoholethoxy sodium benzene sulphonate (containing 5 ethoxy groups per molecule), abbreviated DEBS 25-5. The hatched area of the phase diagram coincides with a single phase area in a phase diagram of seawater/DABS and DEBS 25-5, without oil, at 95° C. as well as at 20° C. The formulations can be injected at 20° C. The invention will now be described further by means of the following example which is illustrative and is not intended to be construed as limiting the scope of the claimed invention. EXAMPLE A surfactant composition according to the invention was tested on its oil production performance in an outcrop sandstone (Bentheim core) at 95° C. The composition comprised the same surfactants as disclosed above in relation with FIG. 1, namely C 8 -C 10 -dialkylated sodium benzene sulfonate (DABS) and C 12 -C 15 -alcohol ethoxy sodium benzene sulfonate (DEBS 25-5) in a concentration of 12.76 g/l and 20.83 g/l respectively. The properties of the Bentheim core were as follows. ______________________________________Length 31.0 cmArea 24.0 cm.sup.2Porosity 20.7%Pore volume 154.0 mlPermeability 1300 mD(arcy)K.sub.ocw 440 mDK.sub.wor 80 mDS.sub.cw 29%S.sub.or 43%______________________________________ The Bentheim core was firstly saturated with seawater, brought to connate water saturation by injecting North Sea crude oil and was followed by a seawater drive. The result of this flood is found in FIG. 2. The cumulative recovery is 39% of the oil initially in place (OIIP). OIIP was 70.8% of PV. For the subsequent surfactant drive, the core was resaturated with crude oil until the connate water saturation was restored. The surfactant composition was injected (total volume 1.75 PV (pore volume)). The result of the surfactant flood is given in FIG. 3. Water breakthrough occurred after 0.39 PV injection, compared with 0.24 PV for the water drive. The subsequent oil bank was produced with an oil cut of 43% and lasted until 1.0 PV total injection. Thereafter clean oil continued to be produced at an average oil cut of 22% during 0.3 PV. An oil-containing micro-emulsion was produced over a period of about 0.4 PV. If oil present in the micro-emulsion was included, the oil recovery reached 100% at 1.4 PV. ______________________________________DATA OF THE VERTICALSURFACTANT FLOOD EXPERIMENT______________________________________WATERFLOODMoveable pore volume (PV) 0.28Water breakthrough (PV) 0.24Oil production at breakthrough (% OIIP) 32Ultimate waterflood recovery (% OIIP) 39S.sub.or (%) 43SURFACTANT FLOODWater breakthrough (PV) 0.39Cum. clean oil production at: 1.0 PV 91(% OIIP) 1.2 PV 97 1.4 PV 100Cum. total oil production at: 1.0 PV 91(% OIIP) 1.2 PV 98 1.4 PV 100______________________________________

A surfactant composition, suitable for enhanced oil recovery comprising in a 60:40 to 10/90 weight ratio a) (o,m)- and/or (o,p)-dialkylbenzene alkali sulfonate and b) polyalkoxyphenyl ether alkali sulfonate.

CROSS REFERENCE TO RELATED APPLICATIONS [0001] None. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT [0002] None. LATIN NAME OF THE GENUS AND SPECIES [0003] Ilex×attenuate VARIETAL DENOMINATION [0004] Holly tree which I have named ‘IABOF’. BACKGROUND OF THE INVENTION [0005] The present invention relates to a new and distinct variety of a holly tree ( Ilex×attenuata ), which I have named ‘IABOF’. Discovery: [0007] I discovered my new tree in the summer of 2002 growing in a production field in Belleview, Fla. among a group of cultivated East Palatka holly trees. These trees were grown from 3 gallon liners purchased in the spring of 2001 from a nursery in Florida. In the summer of 2002, these liners were stepped up into larger containers and relocated to a production field. It was here that I discovered the claimed cultivar ‘IABOF.’ Evaluation of this tree continued in this field until it was relocated to an observation area at the University of Georgia, Department of Horticulture Coastal Plain Experiment Station in Tifton, Ga. in 2006. Propagation: [0009] ‘IABOF’ was asexually propagated by the method of vegetative cutting in the summer of 2003 in Belleville, Fla. using four inch long cuttings quick dipped in 2500 Indole-3-butyric acid and 1250 1 -naphthaleneacetic acid without wounding. This propagation from semi-hardwood cuttings in a peat-perlite media took approximately 10 weeks to complete. Resulting progeny has proven the characteristics of my new variety to be genetically stable. Furthermore, these observations have confirmed that my new variety represents a new and improved variety of holly tree as particularly evidenced by a shorter internode length which develops a more compact, dense canopy, an increased caliper to height ratio, and reduced berry weight load. Uniqueness: [0011] ‘IABOF’ was discovered in a block of seedling East Palatka holly trees purchased by a nursery from a supplier of liners in Florida. I claim that the genetic characteristics of this tree are the result of naturally occurring cross-pollination. Due to the nature of the liner purchase, the exact source of the mutation is not known. These improved characteristics distinguish my new trees from other typical East Palatka holly trees. At the time this tree was selected, I observed the ‘IABOF’ holly tree as a darker green, compact growing holly tree having a heavy caliper, reduced fruiting weight load, and tight internode spacing. The remaining trees in this block were typical of the species with irregular structure, branches drooping from berry weight, and signs of Sphaeropsis knot susceptibility. I claim that my ‘IABOF’ exhibits improved structural and aesthetic qualities in comparison to traditional East Palatka holly trees. Use: [0013] ‘IABOF’ was observed for a period of several years and is believed to be particularly useful for street tree planting and in large areas such as, but not limited to, golf courses, commercial sites and parks. ‘IABOF’ will also benefit growers who will profit from a consistent growing tree having a compact form and reduced weight load damage resulting from berry production. SUMMARY OF THE INVENTION [0000] Background: [0015] An East Palatka holly tree, which was discovered as a hybrid in East Palatka, Fla. in the 1920's, is typically pyramidal-shaped in youth and develops an upright oval canopy at maturity. The East Palatka holly tree is native to central Florida. It thrives well in the heat and humidity of the southeastern United States. East Palatka holly trees prefer moist, well-drained soils in these areas, but adapts readily to harsh conditions such as poor drainage, compacted soils, and drought. My new cultivar differs from the species in that it is more compact in height and width, heavier in caliper to height ratio, has shorter internode length and is less susceptible to branch damage due to reduced weight of berries. I expect my new variety ‘IABOF’ to perform as well as the species. Industry Representation: [0017] A cultivated East Palatka holly tree is represented in the industry by materials reproduced by vegetative cuttings from multiple sources. This accounts for a degree of variability in growth rate and habit both in the landscape industry and nursery industry. East Palatka holly trees are widely used in the coastal southeastern United States as an evergreen screen and specimen accent tree. At the time of this submittal, there is no cultivar selection of East Palatka holly tree that I am aware of in the nursery industry. The dark foliage color, reduced berry load, compact pyramidal form and increased caliper make my selection unique. DESCRIPTION OF THE DRAWINGS [0018] The accompanying photographs depict the color and foliage of my new variety East Palatka holly tree as nearly as is reasonably possible to make the same in a color illustration of this character. [0019] FIG. 1 , taken at the University of Georgia, Department of Horticulture Coastal Plain Experiment Station in Tifton, Ga. in 2006, shows the transplanted parent tree at 5 years old, 6.5 feet high, 3.0 feet wide and 2.0 inches in caliper. This photo depicts pyramidal habit with dense branching; [0020] FIG. 2 , taken at the University of Georgia, Department of Horticulture Coastal Plain Experiment Station in Tifton, Ga. in Late summer of 2006, shows the foliage and fruit of the ‘IABOF’ parent tree; [0021] FIG. 3 shows the lower leaf surface of my new variety of holly tree; and [0022] FIG. 4 shows the trunk of my new variety of holly tree. DETAILED DESCRIPTION [0000] Botanical description of the plant: The following is a detailed description of the ‘IABOF’ holly tree with color terminology in accordance with The Royal Horticulture Society (R.H.S.) color chart except where the context indicates a term having its plain and ordinary meaning. My new tree has not been observed under all growing conditions and variations may occur as a result of different growing conditions. All progeny of my new variety, insofar as have been observed, have remained genetically stable in all characteristics described hereinafter. Other than as set out hereinafter, as of this time, no other characteristics have been observed by the inventor are different from that of common East Palatka holly trees. Parentage.— Seedling of East Palatka holly trees grown from container liner purchased in 2001 from a nursery in Florida. Locality where grown and observed.— ‘IABOF’ holly trees are currently in production at a nursery in Belleview, Marion County, Fla. This area of Marion County has a sandy loam soil type with rainfall that varies between 30 inches and 60 inches annually. This particular area is located in USDA Hardiness Zone 9. Size and growth rate.— The original tree, aged 5 years measured 2.0 inches in caliper at 6.0 inches above the ground. The height of 6.5 feet and spread of 3.0 feet provides a 2.17 height to width ratio. Prior to my ‘IABOF’ holly tree being transplanted to the observation area, the average growth rate was 1.25 feet in height per year. Foliage.— Alternate, simple, ovate-rounded. The leaf margin is entire with a terminal spine, cuspidate tip and cuneate base. Entire dimension: 1.25 inches wide by 2.5 inches long. Upper surface is smooth, waxy with medium green like (RHS 137C). The underside is smooth, waxy and yellow green like (RHS144B). The midrib vein color is yellow green like (RHS144C). The internode length is 0.33 inches. Petiole.— ⅜ inch long with channeled texture on upper surface and orange red like (RHS31C). Stem.— 1 year wood is yellow green like (RHS145B) and has pubescence. Flowers.— Early to mid May without fragrance. Size is ¼ inch wide and 1/10 inch high with 4 oblong petals that have rounded tips that are green white like (RHS157D) fading to grayed-orange like (RHS 1 66D). Buds.— Flower buds are ovate, 1/12 inch long and wide and angled at 30-45 degrees and upright color that is green like (RHS 138B). Fruit.— Occurs in tight clusters that are ⅕ inch to ¼ inch diameter and are glossy red like (RHS43A). Fruit appears in late November to mid December. Trunk.— Smooth, gray, becoming gray-brown like (RHS201 B). At time of submittal, the trunk diameter was 2.0 inches measured 6.0 inches above the ground. Branching.— Slightly ascending to nearly horizontal at the base, emerging at 80-90 degrees from the trunk. Upper branches are more ascending, emerging at 30 degrees or more from the trunk. Color is gray (RHS 195B), becoming gray-brown with age. Shape.— Broad pyramidal with dense branching and dominant central leader. Root system.— Fibrous. Vigor.— In production, the progeny have averaged 1.25 feet of vertical new growth per year. The root development from time of softwood cuttings to a finished rooted 3.5 inch pot is five to seven weeks. Disease.— Less susceptible to Sphaeropsis. Pests.— Susceptible to spittlebug.

A holly tree ( Ilex attenuata ) named ‘IABOF’ having a compact, dense canopy, an increased caliper to height ratio, reduced berry weight load and also capable of being reproduced reliably from vegetative cuttings.

CLAIM OF PRIORITY The present application claims priority to the following provisional application, the contents of which are incorporated by reference herein in their entirety: U.S. Provisional Patent Application No. 60/598,315, entitled SYSTEM AND METHOD FOR RUNTIME INTERFACE VERSIONING, by Neil Smithline, filed on Aug. 3, 2004. CROSS REFERENCE TO RELATED APPLICATIONS The present application relates to the following application, the contents of which are hereby incorporated by reference in their entirety: U.S. patent application Ser. No. 10/373,532 entitled SYSTEM AND METHOD FOR ENTERPRISE AUTHENTICATION, by Paul Patrick, filed on Feb. 24, 2003. COPYRIGHT NOTICE A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. FIELD OF THE INVENTION The present invention relates to systems, methods and computer readable media for upgrading servers. The present invention relates more particularly to enabling interoperability between related software products that are designed to work with different versions of servers. BACKGROUND OF THE INVENTION Since its inception in 1995, the Java™ programming language has become increasingly popular. (Java™ is a trademark of Sun Microsystems, Inc.) Java, which is an interpreted language, enabled the creation of applications that could be run on a wide variety of platforms. This ability to function across a variety of different client platforms, i.e. platform independence, and Java's relatively easy implementation of network applications has resulted in its use in endeavors as basic as personal webpages to endeavors as complex as large business-to-business enterprise systems. As Java has become more commonplace, a wide variety of tools and development platforms have been created to assist developers in the creation and implementation of applications and portals using Java or other languages supporting platform independence. Many of such applications and portals are based around one or more servers that provide, inter alia, application support and control access to resources. It is often desirable to enable third parties to produce custom software modules or plugins that can be inserted into such servers to perform functions that would otherwise be performed by the base software of the server. Server architectures can be designed to enable easy development of plugins for certain features such as security. However, as the interfaces through which the plugins interact with the server are upgraded, plugins that were designed for previous versions of the interfaces may be rendered incompatible. The process of upgrading the plugins can be time consuming and expensive. What is needed is an improved interface that allows legacy plugin products to be used with newer plugin interfaces. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram illustrating one embodiment of a security framework. FIG. 2 is a block diagram illustrating one embodiment of an interaction among a security provider interface, an adapter, and a security provider. FIG. 3 is a block diagram illustrating another high-level view of an adapter in an embodiment. FIG. 4 is a flow chart illustrating one embodiment of a process for utilizing a security provider. DETAILED DESCRIPTION The invention is illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. References to embodiments in this disclosure are not necessarily to the same embodiment, and such references mean at least one. While specific implementations are discussed, it is understood that this is done for illustrative purposes only. A person skilled in the relevant art will recognize that other components and configurations may be used without departing from the scope and spirit of the invention. In the following description, numerous specific details are set forth to provide a thorough description of the invention. However, it will be apparent to those skilled in the art that the invention may be practiced without these specific details. In other instances, well-known features have not been described in detail so as not to obscure the invention. Although a diagram may depict components as logically separate, such depiction is merely for illustrative purposes. It can be apparent to those skilled in the art that the components portrayed can be combined or divided into separate software, firmware and/or hardware components. For example, one or more of the embodiments described herein can be implemented in a network accessible device/appliance such as a router. Furthermore, it can also be apparent to those skilled in the art that such components, regardless of how they are combined or divided, can execute on the same computing device or can be distributed among different computing devices connected by one or more networks or other suitable communication means. In accordance with embodiments, there are provided mechanisms and methods for versioning plugin adapters for servers. These mechanisms and methods can enable embodiments to provide legacy versions of software plugins the capability to function when the interfaces configured to accept the plugins are upgraded. The ability of embodiments to provide plugins with the capability to function when the interfaces configured to accept the plugins are upgraded can enable easier migrations to new versions, extended use from legacy plugins and so forth. In an embodiment, a method for utilizing a plugin product for a server is provided. The plugin product can have an old interface version. One embodiment of the method includes accepting a request directed towards a new interface version of the plugin. The request directed towards the new interface version is converted to a request directed towards the old interface version. The request directed towards the old interface version is transmitted to the plugin. In some embodiments, the request may be a request directed to a security provider. In various embodiments, accepting a request to a security provider accessible via the plugin can include accepting a request for any of: an authentication system, an identity assertion system, an authorization system, and an auditing system. While the present invention is described with reference to an embodiment in which security providers create executable adapter programs written in the Java™ programming language that are executed in conjunction with plugin interfaces adapted to work with legacy versions of software, the present invention is not limited to security providers, nor to the Java™ programming language and may be practiced using other programming languages, i.e., JSP and the like without departing from the scope of the embodiments claimed. (Java™ is a trademark of Sun Microsystems, Inc.) In one embodiment, the servers utilize an application server product, such as WebLogic® Server by BEA systems of San Jose, Calif. FIG. 1 is a block diagram illustrating one embodiment of a security framework of a server. In one embodiment, the server is a Java server. The security framework includes a resource container 118 containing resources 105 , 110 , and 115 . Preferably, the resource container contains all of the resources required by a particular activity or particular group of activities. The resources include information and programs that will be utilized within the activities. The resource container is configured to provide the resources in response to an approved request from a security framework 122 . The security framework 122 includes multiple Service Provider Interfaces (SPIs). These interfaces may also be referred to as Security Provider Interfaces. The SPIs are configured to access security providers that provide security verification services for users attempting access the resources 105 , 110 , and 115 . The SPIs include an authentication SPI 125 . The authentication SPI 125 is configured to utilize an external authentication provider 140 to verify a user's credentials. The authentication provider 140 accepts credentials from a user and uses those credentials to verify the user's identity. The authentication provider 140 , like the identity assertion provider 145 , authorization provider 150 , and adjudication provider 155 is a software plugin that interacts with the security framework 122 through the SPIs. The credentials utilized by the authentication provider can include usernames and passwords, secure tokens, biometric data, secure hardware keys, or any other credentials that can be used to verify a user identity. The authentication provider returns to the security framework 122 a value indicating whether the user has been successfully authenticated and information about the user (e.g. what groups the user belongs to). Another type of SPI is an identity assertion SPI 130 . The identity assertion SPI 130 is configured to accept identity assertions for users from external systems such as the identity assertion provider 145 . The identity assertion SPI can be configured for multiple provider types, including multiple tokens and certificates for verifying a user's identity. The identity assertion SPI provides a response to an authentication request indicating whether a user is permitted to access the resource. An authorization SPI 135 is configured to use an authorization provider 150 to determine whether a user is permitted to access a resource. Once a user's identity has been established through the authentication provider 140 or the identity assertion provider, the authorization provider 150 determines whether the user as currently identified is permitted to access the resource. The security framework also includes an auditing SPI 120 . In some embodiments, the various SPIs can utilize multiple providers. The auditing SPI 120 utilizes an auditing provider 158 to record the various responses from the differing security providers. An adjudication SPI 138 and adjudication provider 155 are configured to resolve a conflict when one exists. For example, in some embodiments, the authentication SPI 125 can utilize multiple authorization providers 150 . If some return a successful authentication and some return an unsuccessful authentication in response to an authentication request, the adjudication provider 155 determines whether the user should be authenticated. In some embodiments, an administrator can set adjudication criteria indicating how conflicts are resolved. For example, the criteria could be set such that a successful authentication from any of the providers, or all of the providers is needed for a user to be considered authenticated. In some embodiments, the security provider also includes role mapping SPIs, credential mapping SPIs and other SPIs for outsourcing security functions to plugins. FIG. 2 is a block diagram illustrating one embodiment of an interaction among a security provider interface 215 , an adapter 210 , and a security provider 205 in an embodiment. The legacy security provider 205 is one of the service providers 140 , 145 , 150 , 155 illustrated in FIG. 1 . The SPI 215 is one of the SPIs 125 , 130 , 135 , 138 , 158 illustrated in FIG. 1 . The SPI 215 has a set of interface parameters governing how it will interact with the security provider 205 . These parameters indicate the formatting and content of data transmitted to and received from the security provider 205 . As new versions of the SPI are released, these interface parameters can change, thus requiring that the security provider 205 be updated to interact with the SPIs correctly. However, security providers are often difficult to update, requiring considerable amounts of time and expense. Thus, legacy providers 205 often remain in place long after the SPI 215 is updated. Thus, an adapter 210 is used to translate information passed between the SPI 215 and the security provider 205 . The adapter 210 receives communications from the SPI 215 configured for a new version of the provider 205 , and translates the communications into communications configured for the legacy version of the provider 215 . The adapter also receives communications configured for the legacy version of the SPI and converts the communications to communications designed for the new version of the SPI. In some embodiments, the adapter 210 “wraps” the service provider, generating a new service provider object that interacts with SPI as a provider 215 , but is capable of converting requests between versions. FIG. 3 is a block diagram illustrating another high-level view of an adapter in an embodiment. The adapter includes an input module 305 that is configured to receive communications from either the SPI 205 or the security provider. These communications are passed to a translator 310 . The translator 310 receives the communications and according to the type of communications, translates them as necessary. The translator 310 preferably stores information indicating a version of the SPI 205 and the security provider 215 . In some embodiments, the translator can translate between multiple differing versions of the SPI and providers. When the translator 310 receives input from the SPI 205 or the provider 215 through the input module, it converts it to output that is configured for the type of the destination and passes it to an output module 315 . While in the present embodiment, the adapter 210 is used to bridge communications between legacy security providers and new SPIs, in alternate embodiments, adapters can be used to enable any type of plugin having similar compatibility issues. Disclosed below is computer code for implementing an adapter for an authorization provider in an embodiment. package weblogic.security.service.adapters; import javax.security.auth.login.AppConfigurationEntry; import weblogic.security.spi.AuthenticationProvider; import weblogic.security.spi.AuthenticationProviderV2; import weblogic.security.spi.ChallengeIdentityAsserter; import weblogic.security.spi.ChallengeIdentityAsserterV2; import weblogic.security.spi.IdentityAsserter; import weblogic.security.spi.IdentityAsserterV2; import weblogic.security.spi.PrincipalValidator; public class AuthenticationProviderV1Adapter extends SecurityProviderV1Adapter implements AuthenticationProviderV2 { public AuthenticationProviderV1Adapter(AuthenticationProvider provider) { base = provider; } public AppConfigurationEntry getLoginModuleConfiguration() { AuthenticationProvider atn = (AuthenticationProvider) base; return atn.getLoginModuleConfiguration(); public AppConfigurationEntry getAssertionModuleConfiguration() { AuthenticationProvider atn = (AuthenticationProvider) base; return atn.getAssertionModuleConfiguration(); } public Principal Validator getPrincipalValidator() { AuthenticationProvider atn = (AuthenticationProvider) base; return atn.getPrincipalValidator(); } public IdentityAsserterV2 getIdentityAsserter() { AuthenticationProvider atn = (AuthenticationProvider) base; IdentityAsserter asserter = atn.getIdentityAsserter(); if (asserter instanceof ChallengeIdentityAsserter) { return new ChallengeIdentityAsserterV1Adapter((ChallengeIdentityAsserter)asserter); } else { return new IdentityAsserterV1Adapter(asserter); } } } FIG. 4 is a flow chart illustrating one embodiment of a process for utilizing a security provider. In block ( 405 ) the security framework 122 receives a request for a protected resource. In block ( 410 ) the security framework creates a provider object from the security provider. Creating a provider object can entail generating an object to perform the provider's tasks. In block ( 412 ), the system determines whether the provider object uses a current version of the interface or a legacy version. If the provider uses the current interface version, the process jumps to block ( 420 ), where the existing provider is utilized as the provider object. If the provider uses the legacy interface, the process moves to block ( 415 ), in which it wraps the existing provider around the adapter. In some embodiments, block ( 415 ) is implemented by the code disclosed below: SecurityProvider provider= AdapterFactory.getAuthenticationProvider(mbean, auditor); The code disclosed above utilizes an adapter factory to produce an adapter module instance, that with the SPI, communicates with the service provider. The security framework 122 does not need to be aware of any conversion steps being performed by the adapter, instead only receiving notification from the SPI of the response (i.e., successful/unsuccessful authentication/authorization etc.). In block ( 420 ), the security provider is utilized to return an authentication/authorization response. If the security provider and adapter have the same version, the adapter does not perform any conversion. The type of conversion depends on the level of change between the two versions of the plugin interface. For example, in the case of an improved identity assertion SPI, an original version of a method used to access the identity assertion provider might call the identity assertion provider with one argument, whereas the improved SPI calls the provider with two arguments. The adapter receives the two-argument call from the SPI, and makes a call to the provider with a single argument. The new wrapped security provider is used for future operations. In some embodiments, the creation of the provider object and wrapping of the adapter occurs during an initiation/bootup/deployment stage rather than when a specific request is received. It should also be understood that while a security provider is discussed as an exemplary embodiment, the embodiments discussed above can be applied to any type of software plugin. Other features, aspects and objects of the invention can be obtained from a review of the figures and the claims. It is to be understood that other embodiments of the invention can be developed and fall within the spirit and scope of the invention and claims. The foregoing description of preferred embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to the practitioner skilled in the art. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention for various embodiments and with various modifications that are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the following claims and their equivalence. In addition to an embodiment consisting of specifically designed integrated circuits or other electronics, the present invention may be conveniently implemented using a conventional general purpose or a specialized digital computer or microprocessor programmed according to the teachings of the present disclosure, as will be apparent to those skilled in the computer art. Appropriate software coding can readily be prepared by skilled programmers based on the teachings of the present disclosure, as will be apparent to those skilled in the software art. The invention may also be implemented by the preparation of application specific integrated circuits or by interconnecting an appropriate network of conventional component circuits, as will be readily apparent to those skilled in the art. The present invention includes a computer program product which is a storage medium (media) having instructions stored thereon/in which can be used to program a computer to perform any of the processes of the present invention. The storage medium can include, but is not limited to, any type of disk including floppy disks, optical discs, DVD, CD-ROMs, microdrive, and magneto-optical disks, ROMs, RAMs, EPROMs, EEPROMs, DRAMs, VRAMs, flash memory devices, magnetic or optical cards, nanosystems (including molecular memory ICs), or any type of media or device suitable for storing instructions and/or data. Stored on any one of the computer readable medium (media), the present invention includes software for controlling both the hardware of the general purpose/specialized computer or microprocessor, and for enabling the computer or microprocessor to interact with a human user or other mechanism utilizing the results of the present invention. Such software may include, but is not limited to, device drivers, operating systems, and user applications. Included in the programming (software) of the general/specialized computer or microprocessor are software modules for implementing the teachings of the present invention.

The present invention provides methods, machine readable memories and systems for versioning plugin adapters for servers so as to allow legacy versions of software plugins to function when the interfaces configured to accept the plugins are upgraded. An adapter resides between a plugin interface and the plugin module and converts requests designed for a current or new version to requests designed for legacy versions. In some embodiments, the interface elements are designed to extend and adapt the functionality of a security apparatus by enabling the security apparatus to utilize third party security providers.

BACKGROUND OF THE INVENTION [0001] Tissue defects are sometimes repaired with porous scaffolds comprising biocompatable materials. The porous nature of the devices allows the inward migration of cells, followed by the in-growth of tissue, thereby repairing the defect. The pore structure must be controlled to ensure optimal inward cell migration (e.g., sized large enough to accommodate cells, and avoid altering the cell phenotype), from which the new tissue may form. Current devices do not adequately control pore geometry, size, and distribution, with processes that are economically attractive. Additionally, open porous networks facilitate cell migration throughout the implant, thereby speeding up regeneration. Also, mechanical properties of existing porous structures are less than desirable for applications where the implant is subjected to post implant stresses. The porous nature also minimizes the amount of foreign material placed into the patient. [0002] Most processes for producing porous biomaterial implants utilize a leaching method wherein a leachable substance such as sodium chloride is mixed with a biomaterial such as polymethylmethacrylate (PMMA) and later removed with a solvent such as water. U.S. Pat. No. 4,199,864 (Ashman), U.S. Pat. No. 4,636,526, (Dorman et al), and U.S. Pat. No. 5,766,618 (Laurencin et al), describe such methods. Such leaching methods are time consuming and in many instances only a portion of the leachable substance is effectively removed from the implant. [0003] Other processes for creating porous medical implants utilize a vacuum freezing operation as described in U.S. Pat. No. 6,306,424 (Vyakarnam, et al), U.S. Pat. No. 5,766,618 (Laurencin et al), and U.S. Pat. No. 5,133,755 (Brekke). These processes are not generally suited to mass production and often utilize non-biocompatable solvents. [0004] A “plasticized melt-flow” process (PMF) has been developed, in an effort to increase the strength, and reduce costs, of molded polymeric parts. Such a process is described in U.S. Pat. No. 6,169,122 (Blizard et al) and U.S. Pat. No. 6,231,942 (Blizard et al) and by David Pierick and Kai Jacobsen, “Injection Molding Innovation: The Microcellular Foam Process,” Plastics Engineering, May 2001, pp 46-51 (such disclosures being incorporated herein by reference). In general, such a process uses a gas (e.g., N 2 , or CO 2 ) under high pressures to create a supercritical fluid (SCF). The SCF, when depressurized, liberates the gas, thereby creating a porous structure. [0005] The pores in the PMF processes noted above are nucleated by nucleating agents which are added in the range of 2 to 7 percent. As a result the pores may be more homogeneously dispersed through the molded part, than pores seen in other processing methods known in the art. The Pierick-Jacobsen paper reports that the aim of this technology is reducing costs, through the reduction of polymer used and decreasing cycle time, i.e., nucleating agent takes the place of matrix polymer, thereby reducing the amount of polymer needed. [0006] The process is proposed for use in various industrial components (e.g., car mirror housings, ink and Laserjet printer parts), no medical applications, procedures, or devices are disclosed. [0007] A CESP process (Controlled Expansion of Saturated Polymers), however, has been contemplated for use in manufacturing implantable polymer structures by Pfannschmidt, et al, “Production of Drug-Releasing Resorbable Polymer Stents with Foam Structure”, Medical Plastics Technology News, Fall 1999-Winter 1999-2000, pp10-12. The focus of the paper is the use of CESP for the incorporation of “thermally sensitive additives.” These additives are suggested to include proteins and growth factors. The devices proposed to deliver these additives are stents. No structural or load-bearing applications are disclosed. In fact, the focus of the invention is the low temperature processability of the invention, however, the resulting process is not readily mass producible. [0008] The CESP may be useful for the delivery of those agents because of the low temperature employed in the CESP process; that is, as previously mentioned, the temperature is not raised to create flow, but rather the pressure is. Therefore, additives may be used that would not survive the temperature of traditional high-temperature molding techniques. However, the CESP process additionally does not adequately address the problem of satisfactory tissue ingrowth or regeneration. [0009] The need for higher strengths in porous polymers has previously been recognized, as in U.S. Pat. No. 6,169,122 (Blizard, et al), where the process is controlled to minimize the cell (i.e., porosity) growth. The aim of the invention is to create homogeneously distributed pores, of a small size (i.e., preferably below 50 microns). To this end, nucleation aids (e.g., talc and titania) are added to the polymer, in an effort to nucleate a larger number of pores during the decompression step (as previously described). However, this paper does not contemplate the problem of satisfactory tissue ingrowth or regeneration, since it strives to create pores that may not be of suitable size to cause effective cellular differentiation and reproduction. [0010] These approaches to utilizing PMF and CESP types of processes for creating porous polymers , for the repair of tissue, would fall short of what is needed in existing surgical procedures. Higher strengths are paramount for implants that may need to withstand any loading following implant; additionally, some implant products (e.g., screws) require continuing strength to withstand the procedural stress. However, proper cell migration into the implant structure, in most cases, require pores on the order of 100 to 250 microns. Therefore, decreasing the pore size below about 100 microns—while increasing strength—could actually prohibit proper cell ingress. [0011] Additionally, talc or titania nucleation aids may not be suited for certain cellular environments, and may further deter cell ingress, or damage or alter normal cellular function and differentiation if such cells were to infiltrate the implant. [0012] The PMF and CESP processes, as disclosed above, creates pores that typically do not communicate with each other. This isolation slows and potentially prevents the continued ingress of cells, through the entire implant cross section, which may delay tissue development, and/or restrict tissue development to the regions at or near the surface of the implant. [0013] Additionally, the closed cell pores of the PMF process do not address the concerns of heterogeneous degradation that occur in massive biodegradable implants. Hydrolysis is not an erosion phenomenon for most biodegradable polymers, but is, instead, a bulk process with random hydrolytic scission of covalent ester bonds. The correlation of in vivo and in vitro rates of hydrolysis has led to the theory that degradation is not facilitated by enzymatic catalysis, or at least not during the initial loss of molecular weight. Hydrolysis is affected by many factors including crystallinity, molecular weight, polydispersity, sterilization process, geometry of the device, total surface area exposed to interstitial fluid, sight of implantation, etc. Although many functions affect biodegradation, hydrolysis has generally been identified to proceed in four main steps i.e., hydration, strength loss, structural integrity loss, and mass loss. [0014] The closed cell pores of the PMF and CESP processes may exasperate problems associated with heterogeneous degradation by providing multiple isolated chambers separated by a thin membrane. These thin membranes may expedite the movement of body fluids deep into the implant where they may pool for a prolonged period of time isolated from interstitial turnover. [0015] In addition, the pores produced by these, and similar, processes typically have uniform or smooth surfaces between the matrix juncture (similar to that of honeycomb structures). Even if these processes were able to yield pores with open architectures, the smooth walls would not be conducive to cell attachment. [0016] Accordingly, there exists a need for homogenous, mass-producible, higher strength, resorbable implants with large pores. The pores may be modeled (i.e., the surfaces made rough or irregular) or intercommunicating and/or foster cell attachment. Embodiments of the current invention address these and other shortcomings in the prior art. SUMMARY OF THE INVENTION [0017] The present invention provides a resorbable porous structure for healing tissue defects comprising a porous polymer body produced from a process utilizing an SCF but without, in a preferred embodiment, any nucleating aids or fillers. [0018] In yet another embodiment, the present invention relates to an improved porous implant wherein the pores of the implant present a modeling material or agent on their surfaces. This “second” material provides a textured or roughened face to the internal surfaces of pores. Additionally, this second material can be incorporated in sufficient quantity to, among other things, create a microporous network connecting interior closed cell pores with each other as well as the exterior of the device. [0019] In yet another embodiment, the structure is reinforced with a strengthening agent, as will be discussed later. [0020] Certain polymers are very thermally sensitive and extended residence time within melt processing equipment (e.g., PMF equipment) can lead to extensive molecular weight degradation. Other polymers have very narrow processing windows where on the high end of a narrow range the polymer burns and on the low end of the range the polymer does not flow effectively and high stress conditions are created in the final part. By using a gas or solvent to plasticize the polymer, processing temperatures, pressures and time can be reduced. For example, when processing resorbable polymers (e.g. polylactide, polyglycolide, polycaprolactone, etc.), this reduction in processing temperature, pressure and time can help to preserve the molecular weight of the final product. By using described processes for this invention, these polymers can be used for creating large low-stress mass-produced resorbable medical devices. [0021] PMF and PSPC (Phase Separation Polymer Concentration) (as described later) processes may appear complex and varied but in actuality produce similar results. It is recognized that there exists other processes that are known in the art, which also produce analogous systems and results These alternate processes are incorporated herein, to the extent practicable. [0022] In the PMF process, the nucleating agent, if any, can be mixed into a gas permeated plasticized polymer. The gas (e.g. air, oxygen, carbon dioxide, nitrogen, argon, or any inert gas, including combinations thereof) trapped within the polymer begins to expand as the pressure external to the polymer is reduced. As the gas expands it attempts to create uniformly dispersed homogeneous spherical pores. The growth of the pores is disrupted as the walls defining the pores thin to the point that the nucleating agent begins to protrude and therefore the nucleating agent may act as a “modeling agent”. As the gas continues to expand the modeling agent particles begin to interfere with each other and/or the expanding pore walls, and force the pore to take on an irregular shape. [0023] In the PSPC process, the modeling agent is dispersed within a polymer solvent solution. The temperature of the mixture is lowered until crystals form within the solution. As the crystals grow they force the polymer into a smaller and smaller area similar to the expanding gas in the PMF process. The growth of the crystals is disrupted as they come in contact with the modeling agent. As the crystals continue to grow they press the modeling agent particles in contact with each other and are thus forced to grow around the particles in an irregular fashion. After solidification vacuum or leaching, a chilled non-solvent removes the solvent crystals. [0024] By varying the ratio of polymer to modeling agent in the PMF and PSPC processes, the porosity, pore surface texture and geometry of the matrix may be controlled; wherein matrix is polymer, molding agent and porosity combined. Low polymer constituent concentrations combined with longer processing times allows the growth of large pores, thereby affecting mechanical and physical properties. The rate at which the pores grow (via gas expansion or crystal growth, as appropriate) can determine where in the polymer mass the modeling agent is located. Slow growth of pores allows the modeling agent to migrate within the thinning polymer walls and remain covered or encapsulated [see (FIGS. 8 - 10 ). Rapid expansion of the pores does not allow sufficient time for the modeling agent to migrate within the walls resulting in partial exposures of the modeling agent (see FIGS. 11 - 13 ). The modeling agent may also control physical and biologic properties, as will be described later. Examples of polymers useful for current invention are listed in Table 1. TABLE 1 Examples and Subtypes of Bioresorbable Polymers for Construction of the Device of the Current Invention: Alginate Aliphatic polyesters Bioglass Cellulose Chitin Collagen Types 1 to 20 Native fibrous Soluble Reconstituted fibrous Recombinant derived Copolymers of glycolide Copolymers of lactide Elastin Fibrin Glycolide/l-lactide copolymers (PGA/PLLA) Glycolide/trimethylene carbonate copolymers (PGA/TMC) Polylactides (PLA) Glycosaminoglycans Hydrogel Lactide/tetramethylglycolide copolymers Lactide/trimethylene carbonate copolymers Lactide/ε-caprolactone copolymers Lactide/σ-valerolactone copolymers L-lactide/dl-lactide copolymers Methyl methacrylate-N-vinyl pyrrolidone copolymers Modified proteins Nylon-2 PHBA/γ-hydroxyvalerate copolymers (PHBA/HVA) PLA/polyethylene oxide copolymers PLA-polyethylene oxide (PELA) Poly (amino acids) Poly (trimethylene carbonates) Poly hydroxyalkanoate polymers (PHA) Poly (alklyene oxalates) Poly (butylene diglycolate) Poly (hydroxy butyrate) (PHB) Poly (n-vinyl pyrrolidone) Poly (ortho esters) Polyalkyl-2-cyanoacrylates Polyanhydrides Polycyanoacrylates Polydepsipeptides Polydihydropyrans Poly-dl-lactide (PDLLA) Polyesteramides Polyesters of oxalic acid Polyglycolide (PGA) Polyiminocarbonates Polylactides (PLA) Poly-l-lactide (PLLA) Polyorthoesters Poly-p-dioxanone (PDO) Polypeptides Polyphosphazenes Polysaccharides Polyurethanes (PU) Polyvinyl alcohol (PVA) Poly-β-hydroxypropionate (PHPA) Poly-β-hydroxybutyrate (PBA) Poly-σ-valerolactone Poly-β-alkanoic acids Poly-β-malic acid (PMLA) Poly-ε-caprolactone (PCL) Pseudo-Poly (Amino Acids) Starch Trimethylene carbonate (TMC) Tyrosine based polymers [0025] In certain embodiments, the nucleating agent (or modeling agent) may be left out of the processing mix to allow the pores to grow (e.g. since fewer pores are nucleated they may grow larger). Pores in the range of about 50-500 microns may be used in an implant, but may preferably be about 100-300 microns. It is realized that there may be a strength trade-off with this approach. [0026] The modeling agent may also be composed of one or more materials that may have the ability to react with each other to create additional substances within the porosity of the invention. For example, Chitosan and sodium hyaluronate powders can be blended into the polymer and chemically linked to each other within the pores of the invention. This is accomplished by rapid expansion of the pores resulting in exposure of the two modeling agents after which the pores are flooded with a pH-adjusted fluid. The pH-adjusted fluid dissolves the modeling agents within the pores creating a polyelectrolytic system. Within this system chitosan and hylauronate become bound to each other and precipitate out of solution as an insoluble hydrogel. [0027] The incorporation of high modulus strengthening components (e.g., polymers, ceramics or metallics) as the modeling agent will affect the strength and toughness of the resulting structure. The strengthening agent may be in various forms (e.g., particulate, fiber or whisker). The incorporation of these strengthening components improves the strength, such that the pore size may be increased to allow inward cell migration, while retaining or improving the mechanical properties (when compared with a small pore implant without a strengthening component). Additionally, the same modeling agent used to affect the physical properties of the implant can also affect its biologic properties. Hydroxyapatite would not only improve the strength of the implant, but also be capable of, for example, extracting endogenous growth factors from the host tissue bed while functioning as a microporous conduit facilitating movement of interstitial fluid throughout the isolated porosities of the device. Examples of materials useful as modeling agents are listed in Table 2. TABLE 2 Examples of Materials that may be Utilized as Modeling Agents of the Current Invention: Alginate Bone allograft or autograft Bone Chips Calcium Calcium Phosphate Calcium Sulfate Ceramics Chitosan Cyanoacrylate Collagen Dacron Demineralized bone Elastin Fibrin Gelatin Glass Gold Glycosaminoglycans Hydrogels Hydroxy apatite Hydroxyethyl methacrylate Hyaluronic Acid Liposomes Mesenchymal cells Microspheres Natural Polymers Nitinol Osteoblasts Oxidized regenerated cellulose Phosphate glasses Polyethylene glycol Polyester Polysaccharides Polyvinyl alcohol Platelets, blood cells Radiopacifiers Salts Silicone Silk Steel (e.g. Stainless Steel) Synthetic polymers Thrombin Titanium Tricalcium phosphate [0028] The modeling agent can serve multiple purposes which may include but are not limited to: [0029] 1. creating a textured surface on the internal surfaces defining the pores; [0030] 2. creating a microporous conduit system between pores; [0031] 3. reaction-extraction of endogenous growth factors; [0032] 4. carrying and/or delivering drugs, biologically active or therapeutic agents; [0033] 5. function as a drug, biologically active or therapeutic agent; [0034] 6. modifying mechanical properties (e.g. strength, flexibility, etc); [0035] 7. function as an in-vivo leachate to increase the overall porosity. [0036] The irregular pore surfaces formed by the modeling agent serves multiple purposes which may include but are not limited to: [0037] 1. increased surface area provides greater numbers of anchorage points for cell attachment; [0038] 2. increased surface area permits modification to the leaching rate of drugs or other therapeutics; [0039] 3. textured surfaces increase quantity of material that can be coated on the interior pore surfaces; [0040] 4. irregular surfaces increase the resistance to flow through the implant. [0041] 5. engineered surfaces can affect how cells attach, thereby modifying the resulting tissue that is generated. [0042] 6. engineered or roughened surfaces can alter the overall pore geometry, which can affect stresses on differentiating cells, thereby dictating cell differentiation modalities. [0043] Additional materials may also be used at the time of manufacture to control the process output (e.g. plastisizers, surfactants, dyes, etc.) For example, processing the polymer with stearic agents will cause the thinning of matrix between the pores, which is most easily penetrable, or rapidly resorbing, following implantation. This will result in a device with high strength, and interconnected pores, which will afford easier migration of cells through the implant. [0044] In yet another embodiment, the polymer and modeling agent, as well as the pores, once formed, can be invested with drugs or other biologically active or therapeutic agents including cells and cellular components (together “therapy”) for rapid or slow delivery, as will be discussed. Additionally, microspheres may be incorporated for an additional mode of therapy delivery, as will be discussed. The methods of therapy delivery contemplated by the various embodiments of the current invention include: delivery from the polymer constituent, delivery from the pores, delivery from the modeling agent, and/or delivery via microspheres, including any combination of the preceding modalities. These therapies may treat any underlying condition, which necessitated the implant or procedure, and/or the therapy may treat or support the ingrowing or regenerated tissue. Examples of materials that can be incorporated into and/or delivered by the implant are listed in Table 3. TABLE 3 Examples with Some Sub-types of Biological, Pharmaceutical, and other Therapies that can be Incorporated into and/or Delivered via the Device in Accordance with the Present Invention Cellular Material Deliverable via this Invention Adipose cells Blood cells Bone marrow Cells with altered receptors or binding sites Endothelial Cells Epithelial cells Fibroblasts Genetically altered cells Glycoproteins Growth factors Lipids Liposomes Macrophages Mesenchymal stem cells Progenitor cells Reticulocytes Skeletal muscle cells Smooth muscle cells Stem cells Vesicles Some Sub-types of Biological, Pharmaceutical, and other Therapies Adenovirus with or without genetic material Angiogenic agents Angiotensin Converting Enzyme Inhibitors (ACE inhibitors) Angiotensin II antagonists Anti-angiogenic agents Antiarrhythmics Anti-bacterial agents Antibiotics Erythromycin Penicillin Anti-coagulants Heparin Anti-growth factors Anti-inflammatory agents Dexamethasone Aspirin Hydrocortisone Antioxidants Anti-platelet agents Forskolin Anti-proliferation agents Anti-rejection agents Rapamycin Anti-restenosis agents Antisense Anti-thrombogenic agents Argatroban Hirudin GP IIb/IIIa inhibitors Anti-virus drugs Arteriogenesis agents acidic fibroblast growth factor (aFGF) angiogenin angiotropin basic fibroblast growth factor (bFGF) Bone morphogenic proteins (BMP) epidermal growth factor (EGF) fibrin granulocyte-macrophage colony stimulating factor (GM-CSF) hepatocyte growth factor (HCF) HIF-1 Indian hedgehog (Inh) insulin growth factor-1 (IGF-1) interleukin-8 (IL-8) MAC-1 nicotinamide platelet-derived endothelial cell growth factor (PD-ECGF) platelet-derived growth factor (PDGF) transforming growth factors alpha & beta (TGF-.alpha., TGF-beta.) tumor necrosis factor alpha (TNF-.alpha.) vascular endothelial growth factor (VEGF) vascular permeability factor (VPF) Bacteria Beta blocker Blood clotting factor Bone morphogenic proteins (BMP) Calcium channel blockers Carcinogens Cells Stem cells Bone Marrow Blood cells Fat Cells Muscle Cells Umbilical cord cells Chemotherapeutic agents Ceramide Taxol Cisplatin Paclitaxel Cholesterol reducers Chondroitin Clopidegrel (e.g., plavix) Collagen Inhibitors Colony stimulating factors Coumadin Cytokines prostaglandins Dentin Etretinate Genetic material Glucosamine Glycosaminoglycans GP IIb/IIIa inhibitors L-703,081 Granulocyte-macrophage colony stimulating factor (GM-CSF) Growth factor antagonists or inhibitors Growth factors Autologous Growth Factors B-cell Activating Factor (BAFF) Bovine derived cytokines Cartilage Derived Growth Factor (CDGF) Endothelial Cell Growth Factor (ECGF) Epidermal growth factor (EGF) Fibroblast Growth Factors (FGF) Hepatocyte growth factor (HGF) Insulin-like Growth Factors (e.g. IGF-I) Nerve growth factor (NGF) Platelet Derived Growth Factor (PDGF) Recombinant NGF (rhNGF) Tissue necrosis factor (TNF) Tissue derived cytokines Transforming growth factors alpha (TGF-alpha) Transforming growth factors beta (TGF-beta) Vascular Endothelial Growth Factor (VEGF) Vascular permeability factor (UPF) Acidic fibroblast growth factor (aFGF) Basic fibroblast growth factor (bFGF) Epidermal growth factor (EGF) Hepatocyte growth factor (HGF) Insulin growth factor-1 (IGF-1) Platelet-derived endothelial cell growth factor (PD-ECGF) Tumor necrosis factor alpha (TNF-.alpha.) Growth hormones Heparin sulfate proteoglycan HMC-CoA reductase inhibitors (statins) Hormones Erythropoietin Immoxidal Immunosuppressant agents inflammatory mediator Insulin Interleukins Interlukins Interlukin-8 (IL-8) Lipid lowering agents Lipo-proteins Low-molecular weight heparin Lymphocites Lysine MAC-1 Morphogens Bone morphogenic proteins (BMPs) Nitric oxide (NO) Nucleotides Peptides PR39 Proteins Prostaglandins Proteoglycans Perlecan Radioactive materials Iodine-125 Iodine-131 Iridium-192 Palladium 103 Radio-pharmaceuticals Secondary Messengers Ceramide Signal Transduction Factors Signaling Proteins Somatomedins Statins Stem Cells Steroids Thrombin Sulfonyl Thrombin inhibitor Thrombolytics Ticlid Tyrosine kinase Inhibitors ST638 AG-17 Vasodilator Histamine Forskolin Nitroglycerin Vitamins E C Yeast [0045] The resulting embodiments of this invention will be useful in the improved repair and regeneration of various soft tissue (e.g. tendon, muscle, skin) and hard tissue (e.g. bone, cartilage) types. Furthermore, it is contemplated that organs or sections thereof (e.g., liver, a heart valve, etc., see Table 4) may also be re-grown or regenerated with implants incorporating the technology of this invention. TABLE 4 Examples of tissues and procedures potentially benefiting from the present invention Ankle reconstruction Artery Biopsy Bone Bone biopsy Bone tissue harvest Burn treatment Bypass surgery Cardiac catheterization Cartilage Compression fractures Cosmetic Surgery Dental Dura Elbow reconstruction Foot reconstruction Gall bladder Hand reconstruction Heart Heart valve replacement Hip reconstruction/replacement Kidney Knee reconstruction/replacement Ligament Liver Long bone fixation Lung Maxillofacial reconstruction/repair Meniscus Mosaicplasty Muscle Nerves Osteotomy Pancreas Ridge augmentation Shoulder reconstruction Skin Spinal arthrodesis Spinal fixation/fusion Tendon Third molar extraction Topical wound Trauma repair Wrist reconstruction [0046] Suitable materials, and additives, for the polymer constituent of these various embodiments includes, but is not limited to, those listed in the above referenced tables. Various resorbable polymers are contemplated by this invention, but components or constituents may also be made of non-resorbable materials, as well. In this regard, In these various embodiments, as well as the balance of the specification and claims, the term “resorbable” is frequently used. There exists some discussion among those skilled in the art, as to the precise meaning and function of resorbable materials (e.g., polymers, ceramics), and how they differ from bioabsorbable, absorbable, bioresorbable, biodegradable, and bioerodable materials. The current disclosure contemplates all of these materials, modalities, or mechanisms, and considers them as equivalent with regard to the function of the current embodiments, even though these processes may be proved to differ significantly in practice, as they are similar in objective and result. BRIEF DESCRIPTION OF THE DRAWINGS [0047] [0047]FIG. 1 shows the process by which pores having a textured surface grow into irregular shapes. The drawings focus in on 3 time points in a dynamic process (FIGS. 1 A-B, 1 C-D, 1 E-F). FIG. 1A shows the genesis of pores 110 in the polymer 100 filled with a modeling agent 120 . The pores 110 are the result of expanding gas, vapors, or crystals. FIG. 1B fills in the polymer and modeling agent with a solid black color 190 so that the shape and orientation of the pores 110 can be easily identified. FIG. 1C show the expanding pores 150 coming in contact with modeling agent 140 while pushing polymer 130 out of the way. [0048] [0048]FIG. 1D fills in the polymer and modeling agent with a solid black color 190 so that the texturing of the pores 150 can be easily identified. In FIG. 1E, the modeling agent particles 170 has been pushed together by the further expanding pores 180 . As the modeling agent particles 170 interfere with each other the pores 180 are forced into irregular shapes. The polymer 160 separating the pores has now been squeezed into thin partitions. [0049] [0049]FIGS. 2 and 3 are Scanning Electron Microscope (SEM) images of porous polymer constructs not using a modeling agent, showing a smooth flowing surface, and regularly shaped pores. [0050] [0050]FIG. 4 shows a SEM image of a porous polymer construct using an insufficient quantity of particulate to be classified as a modeling agent. showing smooth flowing surfaces and regularly shaped pores. [0051] [0051]FIG. 5 demonstrates a construct containing approximately the minimal amount of particulate to be considered a modeling agent. Notice the textures surface and weakly irregular pore structure. [0052] [0052]FIGS. 6 and 7 demonstrate constructs containing sufficient quantities of particulate material to be classified as, and have the desired effect of, modeling agents. Notice the highly textured surfaces and large irregular pores resulting from the modeling agents presence. [0053] FIGS. 8 - 10 show constructs demonstrating the use of microspheres as a modeling agent to create irregular pores with a textured surface wherein the modeling agent is embedded into and covered by the polymer. [0054] FIGS. 11 - 13 show constructs demonstrating the use of microspheres as a modeling agent to create irregular pores with a textured surface wherein the modeling agent is held on the surfaces of the pore walls. [0055] [0055]FIG. 14 shows a cross-section of a bone screw, as an example of an application of such a product created by this process. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0056] An ideal tissue repair/treatment/prosthetic device should possess various of the following properties: (1) it should be chemically biocompatable; (2) it should be partially if not completely resorbable so that the patient's own tissue ultimately replaces at least a portion of the device; (3) it should be porous to allow the infiltration of cells over time; (4) the porosity should provide it with a high surface area to mass ratio for cell attachment and delivery of therapeutics; (5) despite the porosity, it should provide a high degree of structural integrity in order to support, fixate, or treat surrounding tissues until the patient's own bone/tissue heals; (6) the device should have the ability to incorporate additives used to enhance the mechanical or biochemical performance of the device (e.g. strengthening agents, cells, drugs, biomolecules, other agents); and, (7) the device should be mass manufacturable to be able to provide the product at a reasonable price to the consumer. The various embodiments of the current invention address these properties. [0057] The basic PMF process entails four general steps: 1) gas dissolution, 2) nucleation, 3) cell growth, and 4) shaping. During gas dissolution, a blowing agent or supercritical fluid (e.g., CO 2 or N 2 ) is injected into molten polymer (together the “chamber material”), in a pressurized process chamber. During nucleation, the gas, which is in solution within the polymer melt, comes out of solution to form a suspension of bubbles within the melt (i.e., acts as a “pore induction fluid”). This occurs as a result of a change in the conditions that affect the solubility of the gas within the polymer melt. For example, a rapid pressure drop or temperature change would affect gas solubility. In some instances, a nucleating agent such as talc is added to the chamber material to promote the formation of a nucleation site. As such, the processing conditions and the presence of a nucleating agent can affect, and therefore lead to control of, the cell growth. The shaping of the final part is controlled by the mold or by some type of final post processing (e.g. machining). [0058] In a preferred embodiment, the improved process of the current invention entails the combining of a system for delivering controlled gas dispersion with a system for producing the porous component in its final form. The component may be produced by one of several methods traditionally used in the manufacture of plastic products. These include injection molding, extrusion, and blow molding. [0059] The gas delivery unit provides a high pressure, accurately metered flow of gas that has reached a stage of Supercritical Flow (SCF). This gas in its SCF state is then delivered to the plastic process equipment at a point in the melt flow of the plastic material that has been determined to produce a final molded or extruded component with an optimized degree of porosity. The addition of a modeling material (as previously described), at this stage or earlier, may result in the formation of irregular pores with a textured surface. [0060] In various of these embodiments, the optimization of this system includes the balancing of three conditions: 1. The gas blowing agent chosen may be introduced in amounts higher than conventionally used in foaming applications and must be completely dissolved in the polymer before pressure is lowered; 2. The blowing agent or SCF gas stays in solution in the melt flow by maintaining a consistent pressure profile; 3. There must be a high rate of change of solubility versus pressure. [0061] The gas delivery system must introduce the proper amount of SCF gas into the melt flow in the plasticising unit of the injection molding or extrusion equipment to create the desired effect on the melt flow. This gas must be introduced at a pressure that is higher than pressure existing in the plasticising unit. In a preferred embodiment, the chamber material may be heated to improve flowablility or to tailor the resulting porosity. Heat may be supplied to the chamber material while it is under pressure in the chamber and/or while it is being expanded in the mold. [0062] Both injection molding and extrusion or blow molding applications of the PMF system should require customization of a standard plasticizing unit to allow creation of a homogeneous and single-phase polymer melt solution, which, in a preferred embodiment, contains a modeling agent. Changes to tooling may be required to optimize production of specific components. In addition, the software that controls machine cycle functions of an injection molding or other processing system may need to be modified. [0063] In yet another embodiment, the process includes subjecting the polymer and any modeling agent to solvent vapors under high pressure. The solvent vapors penetrate and plasticize the polymer without the addition of high heat. The polymer is then rapidly subjected to reduced pressure thereby boiling off the solvent vapors, expanding the polymer and leaving behind a porous structure. Solvents with low boiling points are favorable in this process (e.g. acetone, tetrahydrofuran, etc.) [0064] In yet another embodiment, the modeling agent is dispersed within a polymer solvent solution. The temperature of the mixture is lowered until crystals form within the solution. As the crystals grow they force the polymer into a smaller and smaller area similar to the expanding gas in the PMF process. The growth of the crystals is disrupted as they come in contact with the modeling agent. As the crystals continue to grow they press the modeling agent particles in contact with each other and are thus forced to grow around the particles in an irregular fashion. After solidification vacuum drying or leaching in a chilled non-solvent removes the solvent crystals. [0065] In addition to catalyzing the formation of irregular shaped pores with a textured surface, a preferred embodiment uses the modeling agent as a strengthening component. The strengthening components are added to the matrix, thereby increasing strength and/or toughness. These strengthening components may be polymers, resorbable or non-resorbable, which may be suitable for primary matrix components themselves (but vary in a mechanical or physical property from the primary polymer); or the strengthening component may be non-polymeric (e.g., ceramic). [0066] There are numerous ceramic systems that display both biocompatability and degradability. One application of devices made with the process of this invention is devices for repair of bone. In the body, the bone itself is the natural storehouse of minerals. The major mineral component of bone is hydroxyapatite, a form of calcium phosphate. Other calcium phosphate salts in bone include monotite, brushite, calcium pyrophosphate, tricalcium phosphate, octocalcium phosphate, and amorphous calcium phosphate. Additionally, bone contains calcium carbonates. Hydroxyapatites and tricalcium phosphates are the most widely studied of the calcium phosphates, which have calcium to phosphate ratios of between 1.5 and 1.67, respectively. Calcium phosphate, Ca 10 (PO 4 ) 6 (OH) 2 , is known as a physiologically acceptable biomaterial which is useful as a hard tissue prosthetic. Another calcium mineral used as a bone replacement material is calcium sulfate. Each of these materials either alone or in combination with other materials would serve as suitable strengthening agents. In addition, it is recognized that other osteoinductive, osteoconductive, and inert materials may be suitable for the strengthening agent of the present invention. [0067] Alternatively, strengthening agents may comprise fibers, whiskers, platelets or other oriented additions. These agents also may be resorbable, non-resorbable, or even non-polymeric in composition. [0068] [0068]FIG. 14 shows a cross-section of an implantable screw (e.g. a bone screw) which may be manufactured by the current invention. The typical screw 200 comprises a body 210 with threads 220 or other attachment or securement means (e.g. barbs, etc.), not shown. The screw may have a geometry to accommodate an insertion device, for example a slot 230 or a hexagonal indentation, etc. (not shown) such screw may have a pointed or semi-pointed end 240 , or it may be blunt (not shown). Various other fixation and reconstructive devices are contemplated by this invention, including but not limited to fixation plates, rods, pins, rivets, anchors, cages, brackets, etc. [0069] The methods of therapy delivery contemplated by the various embodiments of the current invention include: delivery from the polymer constituent, delivery from the pores, delivery from the modeling agent, delivery from a coating, and/or delivery via microspheres, including any combination of the preceding modalities. [0070] Polymer constituent therapy delivery may be through various mechanisms, including but not limited to, therapy incorporated into the polymer constituent by physical entrapment or by conjugation of the therapy with the monomer or polymer. [0071] Therapy delivery may come from the pores, as release from physical entrapment of the therapy from an enclosed pore, it may come from material adsorbed or loosely adhering to the surface of enclosed or interconnected pores, or it may stay suspended within the pores of the implant awaiting contact with cells entering the pores. [0072] It is recognized that each of the delivery modes could result in different delivery rates. That is, therapy may evolve more rapidly from interconnected pores, than from isolated pores, which may in-turn release therapy faster than any therapy delivered by the polymer constituent (i.e., as it degrades). [0073] In one embodiment the therapy is co-mingled with the various other constituents and components prior to the processing. This allows for some concentration of the therapy to remain in the polymer constituent, while some of the same therapy migrates or precipitates into the porous region of the matrix. An equilibrium phase diagram for the components and constituents would allow the tailoring of the concentration of therapy in each region (i.e., pore or polymer constituent), additionally, therapies with low solubility in either component will aid preferential placement of therapy. Therapy composition, PMF process pressure-temperature parameters, and time, among other variables, will affect the final location and concentration of the therapy. [0074] Addition of a secondary therapy, or other active or inactive agent, may alter the solubility of a primary therapy in either region, thereby altering primary therapy placement. [0075] Alternatively, a secondary therapy may be added because of its complementary therapeutic effect, or because of its preference to precipitate in an alternate region of the matrix (compared with the primary therapy). Any plurality of therapies are deliverable by these techniques. [0076] The therapies may be of various states (i.e., solid, liquid, gas, plasma, etc.), prior to introduction, into the pore forming process; this may affect their ultimate solubility, and it is recognized that the therapy state in the finished matrix may not be the same as what was added. [0077] In some instances it may be beneficial to utilize multiple gases with the polymer processing system. For example, each specific gas could be utilized to carry one or more therapies. The incorporation of the gas into the polymer solution could be customized to optimize the delivery of the therapy. Multiple gases could also be used to create a multi-phasic system of cell sizes and distribution within the final device. [0078] The subject invention can also incorporate cellular additions. Cellular material may be delivered in combination with, or independent of drug delivery. The cellular material may be present on the inside of the implant, outside of the implant, or incorporated within the implant in a porous construct, or other such embodiment. The cellular material may be added to the implant immediately prior to insertion into the body of the living being or may be grown on the implant in the days or weeks prior to implantation so more mature cells are in place when the device is implanted. If the cells are seeded on the implant several days or weeks prior to implantation, the implant may be placed in an in-vitro setup that simulates the in-vivo environment (e.g., where blood or a blood substitute medium is circulated at appropriate pressure and temperature) to acclimate the cells to the host environment. The cell-seeded implant may be incubated in this in-vitro setup at physiologic conditions for several days prior to implantation within the body. Cell seeding techniques have been developed for a variety of cell types. Examples of cellular material that may be seeded on implant include those listed in Table 3. [0079] It is also conceived that a source of cytokines or growth factors (e.g. platelet-rich plasma, bone marrow cells, etc.), whether synthetic, autologous or allograft in origination, can be delivered with the devices of this invention (e.g. incorporated into the implant or delivered via the delivery system). For example, it is known that one of the first growth factors to initiate the cascade leading to bone regeneration are platelet-derived growth factor (PDGF) and transforming growth factor-beta (TGF-β). Each of these growth factors is derived from the degranulation of platelets at the wound, defect or trauma site. It is believed that increasing the presence of such platelets at the wound or trauma site can increase the rate of healing and proliferation needed to regenerate bone. [0080] The application of platelet-rich plasma (PRP) or other autologous blood components is one way to deliver a highly concentrated dose of autologous platelets. PRP is easily prepared by extracting a small amount of the patient's blood and processing it, for example using gradient density centrifugation, to sequester and concentrate the patient's platelet derived growth factors. [0081] Bone marrow may also be added to the present invention to aid in healing and repair. [0082] It is further contemplated that gene therapy may be delivered via the various embodiments of this device. Gene therapies are currently of two primary types, and are both together hereinafter referred to as “gene therapy” or “engineered cells”, however others are anticipated; the primary methodologies and basic understandings are described herein (see also table 3). [0083] First, nucleic acids may be used to alter the metabolic functioning of cells, without altering the cell's genome. This technique does not alter the genomic expressions, but rather the- cellular metabolic function or rate of expression (e.g., protein synthesis). [0084] Second, gene expression within the host cell may be altered by the delivery of signal transudation pathway molecules. [0085] In a preferred embodiment, mesenchymal stem cells are harvested from the patient, and infected with vectors; currently, preferred vectors include phages or viri (e.g., retrovirus or adenovirus). This preferred infection will result in a genetically engineered cell, which may be engineered to produce a growth factor (e.g., insulin like growth factor (IGF-1)) or a morphogen (e.g., bone morphogenic protein (BMP-7)), etc. (see also those listed in Table 3). Methods of infection as well as specific vectors are well known to those skilled in the art, and additional ones are anticipated. Following this procedure, the genetically engineered cells are loaded into the implant. Cytokines as described and used herein are considered to include growth factors. [0086] Loading of the cells in this embodiment may be achieved prior to processing, during, or immediately following the implantation procedure. Loading may be achieved by various methods including, but not limited to, the injection of a solution containing said engineered cells into the implant, by combining said cells with said matrix components prior to fabrication, or following fabrication or implant. [0087] The term “microsphere” is used herein to indicate a small additive that is about one to three orders of magnitude smaller (as an approximate relative size) than the implant. The term does not denote any particular shape, it is recognized that perfect spheres are not easily produced. In addition to true spheres, the present invention contemplates elongated spheres and irregularly shaped bodies. “Nanosphere” is used herein to denote particles, whether spherical or irregular, that are several orders of magnitude smaller than microspheres. [0088] Microspheres can be made of a variety of materials such as polymers, silicone and metals. Biodegradable polymers are ideal for use in creating microspheres for use in these embodiments (e.g., see those listed in Table 1). The release of agents from bioresorbable microparticles is dependent upon diffusion through the microsphere polymer, polymer degradation and the microsphere structure. Although most any biocompatible polymer could be adapted for this invention, the preferred material would exhibit in vivo degradation. It is well known that there can be different mechanisms involved in implant degradation like hydrolysis, enzyme-mediated degradation and bulk or surface erosion. These mechanisms can alone or combined influence the host response by determining the amount and character of the degradation product that is released from the implant. The most predominant mechanism of in vivo degradation of synthetic biomedical polymers like polyesters and polyamides is generally considered to be hydrolysis, resulting in ester bond scission and chain disruption. In the extracellular fluids of the living tissue, the accessibility of water to the hydrolysable chemical bonds makes hydrophilic polymers (i.e. polymers that take up significant amounts of water) susceptible to hydrolytic cleavage or bulk erosion. Several variables can influence the mechanism and kinetics of polymer degradation. Material properties like crystallinity, molecular weight, additives, polymer surface morphology, and environmental conditions. As such, to the extent that each of these characteristics can be adjusted or modified, the performance of this invention can be altered. [0089] In a homogeneous embodiment (i.e., monolithic or composite of uniform heterogeneity) of a therapy delivering implant material, the device provides continuous release of the therapy over all or some of the degradation period of the device. In an embodiment incorporating microspheres, the therapy is released at a preferential rate independent of the rate of degradation of the matrix resorption or degradation. In certain applications it may also be necessary to provide a burst release or a delayed release of the active agent. The device may also be designed to deliver more than one agent at differing intervals and dosages, this time-staged delivery also allows for a dwell of non-delivery (i.e., a portion not containing any therapy), thereby allowing alternating delivery of non-compatible therapies. Delivery rates may be affected by the amount of therapeutic material, relative to the amount of resorbing structure, or the rate of the resorption of the structure. [0090] Time-staged delivery may be accomplished via microspheres, in a number of different ways. The concentration of therapeutic agent may vary radially, that is, there may be areas with less agent, or there may be areas with no agent. Additionally, the agent could be varied radially, such that one therapy is delivered prior to a second therapy—this would allow the delivery of non-compatible agents, with the same type of sphere, during the same implant procedure. The spheres could also vary in composition among the spheres, that is, some portion of the sphere population could contain one agent, while the balance may contain one or more alternate agents. These differing spheres may have different delivery rates. Finally, as in the preceding example, there could be different delivery rates, but the agent could be the same, thereby allowing a burst dose followed by a slower maintained dose. [0091] Thus since the invention disclosed herein may be embodied in other specific forms without departing from the spirit or general characteristics thereof, some of which forms have been indicated, the embodiments described herein are to be considered in all respects illustrative and not restrictive. The scope of the invention is to be indicated by the appended claims, rather than by the foregoing description, and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.

Devices and processes (e.g., improved Plasticized Melt Flow processes (PMF) or improved Phase Separation Polymer Concentration (PSPC), etc.) used to make resorbable and non-resorbable structures for treating and/or healing of tissue defects are disclosed. Among the advantages of using these improved processes are the preservation of molecular weight and the broadening of the processing conditions for temperature sensitive polymers and therapies (e.g. polylactide, polyglycolide, polycaprolactone or Cisplatin, etc.). This reduction in processing temperature, pressure and time can help to preserve the molecular weight and/or integrity of the final product or any additive incorporated therein. Additionally, pore size and shape tailoring can increase the osteoconductive nature of the device.

FIELD OF THE INVENTION The present invention relates generally to pupilometry systems and, more particularly, to pupilometry systems having a pupil irregularity detection capability. In one particularly innovative aspect, the present invention relates to hand-held pupilometry systems having a pupil irregularity detection capability, to methods and processing sequences used within such systems, and to methods of using such systems. In another innovative aspect, the present invention relates to a medical diagnostics system incorporating a pupilometer and medical database for correlating actual or derived pupilary image analysis data with stored medical data to formulate medical diagnoses, and to methods of implementing and utilizing such a diagnostics system. BACKGROUND OF THE INVENTION Systems for monitoring pupil size and pupil responsiveness characteristics are well known in the art and are generally referred to as pupilometry systems or, simply, pupilometers. One early pupilometer is described in U.S. Pat. No. 3,533,683, which issued to Stark et al. on Oct. 13, 1970 and is entitled "Dynamic Pupilometers Using Television Camera System." The Stark et al. system employed a television camera system, a digital computer system, an infrared light source, and a visual light stimulator for determining the instantaneous size of a pupil as an eye (or neurologic pupilary control system) of a patient was exposed to various stimuli. Like the early Stark et al. system, conventional pupilometers measure, for example, the diameter of a pupil before and after the pupil is exposed to a light stimulus pulse and also measure the rates at which the pupil may constrict and dilate in response to the initiation and termination of the light stimulus pulse. Pupilometers may comprise hand-held units or, alternatively, may comprise desk or table-mounted, stand-alone units. Pupilometers also generally include some mechanism for ensuring that an imager within the pupilometer is properly positioned in relation to a pupil to be imaged. For example, U.S. Pat. No. 5,646,709, issued to Elbert P. Carter, describes an electronic centering system for ensuring that a pupilometer is properly positioned in relation to a pupil to be imaged. Similarly, U.S. Pat. No. 5,187,506, issued to Elbert P. Carter, describes an eye orbit housing for ensuring proper positioning between a pupilometer and an eye of a subject prior to the initiation of a pupilary scanning procedure. Those skilled in the art will appreciate, however, that for a pupilometer to have maximum utility maximum flexibility should be provided for positioning the imager. For example, in the case of a hand-held system few, if any, restrictions should be placed upon the orientation of the imager prior to enabling an imaging function. The reason for this is that medical personnel at, for example, an accident site may have difficulty in positioning an imager in a prescribed position for acquiring pupilary response data. Thus, it is believed that, for hand-held units in particular, a need exists within the pupilometer field for improved data acquisition and processing systems and methods, as such systems and methods may substantially reduce system dependence on imager orientation and may allow pupilometers to become more user friendly. Similarly, those skilled in the art will appreciate that a need exists for pupilometers that are capable of evaluating more than a mere pupilary response to light stimulus pulses. For example, it is believed that a substantial need exists for a pupilometer that is capable not only of measuring changes in pupilary diameter in response one or more light stimulus pulses, but also of evaluating pupil shape and/or segmental responses to a visual stimulus. Stated somewhat differently, it is believed that a substantial need exists for a pupilometer having a pupilary shape irregularity or non-uniformity detection capability. Finally, it is believed that a substantial need exists for pupilometer-based diagnostics systems, as such systems may provide medical practitioners with a cost effective, non-invasive means for gathering and assessing numerous physiologic parameters. SUMMARY OF THE INVENTION In one particularly innovative aspect, the present invention is directed toward a pupilometer having a pupil shape irregularity detection capability. For example, a pupilometer in accordance with the present invention may comprise an imaging sensor for generating signals representative of a pupil of an eye, a data processor coupled to the imaging sensor, and a program executable by the data processor for enabling the data processor to process signals received from the imaging sensor and to thereby identify one or more regions of non-uniformity or irregularity within an image of a perimeter of the imaged pupil. In one presently preferred embodiment, the one or more regions of pupilary non-uniformity or irregularity are identified by identifying a center point of a pupil and determining a plurality of radii representing distances from the center point to the perimeter of the pupil along a respective plurality of angles in a R,θ coordinate system. In another innovative aspect, the present invention is directed to a medical diagnostics system incorporating a pupilometer and medical database for correlating actual or derived pupilary image analysis data with stored medical data to formulate medical diagnoses, and to methods of implementing and utilizing such a diagnostics system. In still other innovative aspects, the present invention is directed to improved thresholding and image data processing algorithms for use within a pupilometer. For example, a pupilometer in accordance with the present invention may utilize a plurality of row and column histogram data sets in an iterative fashion to identify a preferred threshold value for locating the pupil of an eye within an image data frame. A pupilometer in accordance with the present invention also may process image frame data to determine a shape and/or diameter of the sclera/iris border of an eye and, thereafter, use the determined shape or diameter to evaluate an orientation of the eye of the patient and/or to correlate measured units with defined units of measurement. Finally, when provided with an additional armature supporting, for example, a visible light emitting diode (LED), a pupilometer in accordance with the present invention may be used to measure afferent or consensual pupilary responses to visual stimulus pulses. In such embodiments, a visual stimulus is applied to an eye under examination, and the response of the monitored pupil is recorded and evaluated. Then, as the monitored pupil is allowed to dilate, a stimulus pulse is applied to the other eye of the patient, to see whether or not the monitored pupil again constricts. Following the second stimulus pulse, the monitored pupil is allowed again to dilate, and a final visual stimulus is applied to the eye under examination. During the final stimulus pulse, the constrictive response of the monitored pupil (or lack thereof) is again measured. By measuring the response of the monitored pupil to each stimulus pulse, it is possible to detect retinal impairment in each eye of the patient. Other objects and features of the present invention will become apparent from consideration of the following description taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a hand-held pupilometer in accordance with a preferred form of the present invention. FIG. 2 is an illustration of a liquid crystal display and keypad that may be provided on a hand-held pupilometer in accordance with the present invention. FIG. 3 is an enlarged cross-sectional view of an imaging section of a hand-held pupilometer in accordance with the present invention. FIG. 4 is a three-dimensional plan view showing a preferred arrangement of a plurality of IR, blue and yellow LEDs that may be used for ocular illumination and stimulation within a pupilometer in accordance with the present invention. FIG. 5 is a block diagram illustrating a group of programming objects that preferably comprise an operating program of a pupilometer in accordance with the present invention. FIG. 6 is a timing diagram illustrating a typical stimulus/illumination sequence for the IR, blue and yellow LEDs that may be used within a pupilometer in accordance with the present invention. FIGS. 7(a) and 7(b) are illustrations of histogram data sets that may be developed in accordance with a preferred thresholding algorithm utilized by a pupilometer in accordance with the present invention. FIG. 8 is a flow chart illustrating a basic operating protocol for a pupilometer in accordance with the present invention. FIG. 9 is an illustration of a pupilometer incorporating a consensual measurement attachment in accordance with the present invention. DESCRIPTION OF PREFERRED EMBODIMENTS A. Hardware Components of a Pupilometer in Accordance with the Present Invention Turning now to the drawings, FIG. 1 provides a cross-sectional view of a hand-held pupilometer 10 in accordance with the present invention. FIG. 2 provides an illustration of a liquid crystal display and key pad that may be provided on the hand-held pupilometer 10, and FIG. 3 is an enlarged cross-sectional view of an imaging section of the hand-held pupilometer 10. As shown in FIGS. 1-3, the pupilometer 10 preferably includes a housing 12 wherein an imaging sensor 14, an objective lens 16, first and second beam splitters 18 and 20, a shield 22, four infrared (IR) LEDs 24, two yellow LEDs 26, a blue LED 28 (shown in FIG. 4), a reticle 30, a battery 32, an image signal processing board 34 and a liquid crystal display 36 are mounted. Stated somewhat differently, the pupilometer may comprise a viewing port (reticle 30 and shield 22), an imaging system (objective lens 16, imaging sensor 14 and related image processing electronics), an illumination system (IR LEDs 24, blue LED 28 and related control circuitry) and a stimulus system (yellow LEDs 26 and related control circuitry). 1. The Viewing Port The viewing port (reticle 30 and shield 22) is provided to aid a user in properly positioning the pupilometer 10 for initial data acquisition. By looking through the reticle 30 and shield 22, the user of the pupilometer 10 is able to properly position the pupilometer 10 in front of an eye 38 of a patient, such that an image of the pupil of the patient's eye may be projected onto the imaging sensor 14. The reticle 30 preferably has circular targets (not shown) silk screened or etched on one surface. The targets are positioned along the user's line of sight so as to appear concentric with the iris and pupil of an eye 38 under observation. Those skilled in the art will appreciate that the reticle 30 and shield 22 also serve as environmental barriers and function to minimize exposure of the imaging system to caustic cleaning agents, biological material and airborne dust, all of which can have a negative impact upon the performance of the imaging system. 2. The Imaging System The imaging sensor 14 preferably comprises a N×M bit CMOS imaging sensor of a type that is commercially available. One such imaging sensor is the 384×288 bit, Model OV5017, CMOS imaging sensor manufactured and distributed by Omnivision Technologies, Inc. of Sunnyvale, Calif. The imaging sensor 14 is mounted to an imager board 31 of the pupilometer 10 and is coupled to a microprocessor (not shown) provided on a main processing or mother board 34 of the pupilometer 10. This allows for direct capture of digital images. Images in the form of 8 bit (or greater) gray scale bit maps are stored in system memory for image analysis and display on the liquid crystal display 36 (shown in FIG. 2). The microprocessor(not shown) preferably comprises an Elan SC 400 manufactured and distributed by Advanced Micro Devices, Inc., of Austin, Tex. The imaging system of the present invention is designed such that, when the hand-held pupilometer 10 is positioned in front of the eye 38 of a subject, a properly illuminated and in-focus image of the pupil 43 of the subject's eye 38 is obtained at the sensor plane 40 of the pupilometer 10. The objective lens 16 and a first beam splitter (i.e., wavelength selective filter) 18 preferably are used to focus an image of the pupil 43 of the subject's eye 38 on the sensor plane 40. In a preferred form, the objective lens 16 comprises a five element lens having a focal length of 7.0 mm. The first beam splitter 18 preferably comprises a glass substrate having a thickness of 1.6 mm that is coated with a multi-layer dielectric coating (not shown) to form a wavelength selective filter. The subject side 42 of the beam splitter 18 is coated to enhance reflection at the blue and infrared (IR) wavelength bands with a 45° angle of incidence. The user side 44 of the beam splitter 18 is AR coated to minimize effects resulting from multiple reflections in the image path. Thus, as shown in FIGS. 1 and 3, the beam splitter 18 functions to direct blue and/or IR light generated by the blue and IR LEDs 28 and 24, respectively, toward the eye 38 of a patient and to provide a return path to the imaging sensor 14 for blue and/or IR light that is reflected from the eye 38 ofthe patient. The microprocessor (not shown) provided on the main signal processing board 34 controls the operation and function of the various components comprising the imaging system as described more fully below. 3. The Illumination System The illumination system preferably comprises a blue light emitting diode (LED) 28 and four infrared (IR) LEDs 24. The IR LEDs 24 preferably are arranged symmetrically about the objective lens 16 of the imaging system. The IR LEDs 24 and blue LED 28 are coupled to a flex circuit 33 that is coupled to the main signal processing board 34. When activated by the microprocessor (not shown), the IR LED's 24 emit IR light preferably having a wavelength of substantially 850 nm. Thus, those skilled in the art will appreciate that the emission bandwidth of the IR LEDs 24 lies beyond the physiological response of the human eye but within the photoelectric response of the imaging sensor 14. Stated somewhat differently, while the human eye is unable to detect the IR light emitted by the IR LEDs 24, IR light generated by the IR LEDs 24 and reflected by the eye 38 of a subject may be detected by the imaging sensor 14. The four IR LEDs 24 preferably are arranged in diametrically opposed groups of two, as shown in FIG. 4. By arranging the IR LEDs 24 in the manner shown in FIG. 4, it is possible to more precisely control the IR illumination of a patient's eye 38 and, moreover, to achieve levels of 0, 50 and 100% illumination, if desired. The blue LED 28 is used for ocular illumination in situations where the sclera/iris border of a patient's eye 38 may be difficult to detect with IR illumination alone. As shown in FIG. 4, the blue LED 28 preferably is placed on the same radial arc that is defined by the IR LEDs 24, which surround the objective lens 16. The blue LED 28, when activated by the microprocessor (not shown), preferably emits light having a wavelength of substantially 470 nm. It has been discovered by the inventors hereof that light in the blue color band may be used to substantially improve sclera/iris border image contrast because the iris 37 and sclera 41 of a subject's eye 38 generally have substantially different light absorption and reflection characteristics in the blue color band. Thus, the use of a blue LED 28 for sclera/iris border imaging is believed to be a particularly innovative aspect of the present invention. Because the human eye is responsive to blue radiation, the blue LED 28 preferably is only activated for brief periods of time in relation to the temporal response of a subject's eye 38 or, alternatively, is used in conjunction with the stimulus LEDs 26 described below. Moreover, in a preferred form, IR and blue light illumination of the eye 38 of a subject may be performed in a multiplexed fashion, such that the eye of the subject is illuminated with IR light for a first period of time and, thereafter, illuminated with blue light for a second period of time. This is discussed more fully below with reference to FIG. 6. The microprocessor (not shown) provided on the main signal processing board 34 controls the operation and function of the various components comprising the illumination system as described more fully below. 4. The Stimulus System The stimulus system of the pupilometer 10 comprises two yellow LEDs 26 and a second beam splitter 20. The yellow LEDs 26 preferably are coupled to the flex circuit 33 and, when activated by the microprocessor (not shown), emit light having a wavelength of substantially 570 nm. Like the first beam splitter 18, the second beam splitter 20 preferably comprises a glass substrate having a thickness of 1.6 mm and is coated with a multi-layer dielectric coating (not shown) to form a wavelength selective filter. The subject side 50 of the beam splitter 20 is coated to enhance reflection at the yellow wavelength band with a 45° angle of incidence, and the user side 52 of the beam splitter 20 is AR coated to minimize effects resulting from multiple reflections in the user's observation path. The stimulus system of the pupilometer 10 preferably provides on-axis illumination of the pupil 43 of the eye 38 of a patient, as shown in FIG. 1. B. Software Components of a Pupilometer in Accordance with the Present Invention Turning now to FIGS. 5-7, a pupilometer 10 in accordance with the present invention is a microprocessor based system and, therefore, preferably includes several software components or modules for controlling its operation. As is well know in the art, an operating system provides fundamental machine level interfaces between the hardware elements comprising the pupilometer 10. More specifically, various device drivers are used to provide an interface between the microprocessor (not shown) and the imaging sensor 14, IR LEDs 24, yellow LEDs 26, blue LED 28, keypad 39 and liquid crystal display 36. The highest level of programming or code used within the pupilometer 10 is referred to herein as the P-Program, and the P-Program preferably is divided into five principal objects corresponding to different hardware and mathematical components. The five principal objects are illustrated in block diagram form in FIG. 5 and preferably include a graphic user interface (GUI) object 100, a stimulus/illumination object 102, a CMOS camera object 104, a feature extraction object 106 and an analysis object 108. All of the above-listed objects preferably are developed in Microsoft Visual C++ and Windows CE, and the graphic user interface (GUI) object 100 preferably is based on Win32 Api functions that are available in Windows CE. Visual C++ and Windows CE are software products distributed by Microsoft Corp. of Redmond, Wash. 1. Graphic User Interface (GUI) Object The graphic user interface object 100 allows for data/information exchange between a user and the pupilometer 10. Information relating to the current status of the pupilometer 10 including mode of operation (i.e., direct or consensual response, left or right eye measurement etc.) and the battery level is displayed via the graphic user interface object 100. All inputs and outputs of the pupilometer 10 preferably are coordinated via the graphic user interface object 100. Verification of subject ID numbers and/or patient identification data may be accomplished under control of the graphic user interface object 100. Measurement parameters are determined and set with the assistance of the graphic user interface object 100. Instructions during measurement sequences and images of the iris 37 of the eye 38 of a subject are provided on the liquid crystal display 36 under control of the graphic user interface object 100. Similarly, results of measurement sequences are displayed on the liquid crystal display 36 under control of the graphic user interface object 100, and the option to transfer measurement results to a printer or network computer (not shown) is available through the graphic user interface object 100. 2. Stimulus/Illumination Object The stimulus/illumination object 102 defines and controls the function of the yellow LEDs 26, IR LEDs 24 and blue LED 28 and, therefore, controls the stimulation and illumination of the eye 38 of a subject. The stimulus/illumination object 102 defines the various light profiles (i.e., yellow, IR and blue) as a function of time and controls activation of the yellow, IR and blue LEDs 26, 24 and 28, accordingly. In a typical stimulus/illumination sequence, the LEDs 26, 24 and 28 preferably are activated in the manner described below. However, those skilled in the art will appreciate that the stimulus/illumination sequence may be varied depending upon the circumstances of any given situation, and that variations in the stimulus/illumination sequence may be effected through the user interface object 100. During a typical stimulus/illumination sequence, the LEDs 24, 26 and 28 may be operated as shown in FIG. 6. For example, during a typical measurement sequence, the yellow LEDs 26 may be activated and deactivated for successive 1 second intervals (i.e., "on" for 1 second and "off" for 1 second) for a period of 10 seconds total. Simultaneously, the IR LEDs 24 may be activated for all periods when the yellow LEDs 26 are "off," and may be deactivated, activated and deactivated (i.e., turned "off," "on" and "off") for respective 0.04, 0.92 and 0.04 second intervals, while the yellow LEDs 26 are turned "on." Similarly, the blue LED 28 may be activated, deactivated and activated for respective 0.04, 0.92 and 0.04 second intervals, while the yellow LEDs 26 are turned "on," and may be deactivated during all periods when the yellow LEDs are turned "off." This allows for the operation of the IR LEDs 24 and blue LED 28 to be multiplexed. In such an embodiment, the image frame transfer rate preferably would be set, for example, to 50 frames per second. 3. The CMOS Camera Obiect The CMOS camera object 104 controls the transfer of image data frames between the CMOS imaging sensor 14 and memory associated with the microprocessor (not shown) provided on the main signal processing board 34 (i.e., between the imaging sensor 14 and the P-Program). Preferably, the rate of image frame transfer between the imaging sensor 14 and the memory associated with the microprocessor (not shown) may be programmably set within a range from 1 frame per second to 50 frames per second, depending upon the needs and/or desires of the user. However, those skilled in the art will appreciate that in some instances it may be desirable to provide for faster frame transfer rates, and that such rates might be as high or higher than 100 frames per second. The image frame acquisition or transfer rate is defined by the user under control of the graphic user interface object 100. 4. The Feature Extraction Object The feature extraction object 106 defines several image processing procedures that are used to isolate a pupil within an image and to extract several pupil features such as size, shape and position from each pupil image data frame. All processing procedures defined by the feature extraction object preferably are performed on each image data frame, with the exception of the automatic thresholding procedure described below. The automatic thresholding procedure is applied during an initial calibration phase and, therefore, does not need to be applied to each image data frame. Rather, the results of the automatic thresholding procedure are used during feature extraction processing for each image data frame. The results of the automatic thresholding procedure also may be used to set and/or adjust image exposure gain settings within the system. The feature extraction object 106 employs a flying spot processing algorithm to identify the center of the pupil, a fitted circumference and/or radius of the pupil and, preferably, 48 radii representing the distance between the center and perimeter of the pupil at 48 separate angles in an R,θ coordinate system, where θ defines an angular orientation about the center of the pupil, and R represents the radius of the pupil at that orientation. The fitted radius of the pupil is determined by selecting a circumference that best fits a contour of the pupil and by solving the equation 2πr to obtain the radius value (r). Those skilled in the art will appreciate that, by defining and evaluating 48 distinct radii about the center of the pupil, it is possible in accordance with the present invention to detect one or more non-uniformities or irregularities that may exist around the perimeter of the pupil. It also is possible to characterize the shape of the pupil as circular, elliptical etc. based upon the determined radii. It also is possible to evaluate selected sections of a pupil perimeter to determine whether or not those sections exhibit normal contour characteristics and/or normal responses to visual stimulus. It is believed that these capabilities represent significant improvements over conventional pupilometry systems, as these features allow not only for the performance of conventional pupil aperture and response evaluations, but also for the performance of pupil shape and sectional contour evaluations. Thus, where a particular affliction may produce a defined irregularity in pupil shape or defined sectional response to visual stimulus, the affliction may be identified through the use of a pupilometer in accordance with the present invention. The inputs to, and outputs obtained from, the flying spot algorithm may be defined as follows: Input Parameters: Frame=eye image frame generated by the CMOS imaging sensor 14 Threshold=gray level threshold value; any pixel having a gray scale value greater than the threshold value is considered to be part of the pupil. Output Parameters: Output=fitted radius and center of pupil, 48 radii. It is assumed herein that within the gray scale used by the pupilometer 10 the color black will be associated with a high gray scale value, such as 255, and the color white will be associated with a low gray scale value, such as 0. However, those skilled in the art will appreciate that the relative maximum and minimum values could be reversed. It is believed that the use of flying spot algorithms are well known in the art and, therefore, that the flying spot algorithm need not be described in detail herein. Nonetheless, the basic flying spot procedure may be described as follows. The flying spot procedure starts with a large circumference centered on the image of an eye and iteratively reduces the size of the circumference. In reducing the size of the circumference and adjusting the center location of the circumference, for each iteration the following momentums will be computed: ##EQU1## where N represents the number of pixels having coordinates x,y in the circumference contour; gray -- level -- sign(x,y) is +1, if the gray level value of the pixel (x,y) is greater than the threshold value; gray -- level -- sign(x,y) is -1, if the gray level value of the pixel (x,y) is less than the threshold value; and x0,y0 are the center coordinates of the circumference. The x and y coordinates of the circumference center and the radius are updated as follows: x0=x0+μx* Gain.sub.-- x y0=y0+μy* Gain.sub.-- y radius=radius+μr* Gain.sub.-- r. As indicated above, the updating procedure is applied iteratively, each time calculating the momentum and then changing the center and radius of the flying spot, such that the circumference finally converges to a circumference that best fits the contour of the pupil. Once the fitted radius and center of the pupil are determined, 48 radii representing the distance between the center and perimeter of the pupil at 48 separate angles in an R,θ coordinate system preferably are determined, where θ defines an angular orientation about the center of a pupil, and R represents the radius of the pupil at that orientation. By evaluating the 48 determined radii, it is possible to characterize the overall shape of the pupil and to determine whether or not any sectional non-uniformities or irregularities are present about the perimeter of the pupil. Such processing may be performed either by the feature extraction object 106 or the analysis object 108. Another principal function performed by the feature extraction object is thresholding. The thresholding function automatically identifies a gray level value that separates the pupil from the background in an image data frame. Moreover, when an appropriate threshold value is determined, all pixels having a gray level value greater than the threshold value are considered to comprise part of the image of the pupil, and all pixels having a gray level value less than the threshold are considered to correspond to background. Preferably, the defined threshold value represents the average of a maximum hypothetical threshold value and a minimum hypothetical threshold value. The maximum and minimum hypothetical threshold values are derived through respective histogram analysis routines. Moreover, as shown in FIGS. 7(a) and 7(b), for each hypothetical threshold value two histograms are evaluated, one for the rows of pixels within an image frame, and one for the columns of pixels within the image frame. The histogram value for a given row or column is determined by counting the pixel locations in that row or column that have a gray level value that exceeds the hypothetical threshold level. Thus, the number of values within a histogram preferably corresponds to the number of rows or columns in the image data frame, and each value represents the number of pixels in the specific row or column that have a gray level exceeding the hypothetical threshold value. Turning now in particular to FIGS. 7(a) and 7(b) the hypothetical maximum and hypothetical minimum threshold values are determined by iteratively altering a hypothetical threshold value until a prescribed histogram profile is achieved. An acceptable profile is illustrated in FIG. 7(a) and is one in which a null-high-null pattern is achieved for both a row histogram (y Hist) and column histogram (x Hist). More specifically, an acceptable profile preferably comprises a single "high" bordered by a pair of "nulls." Unacceptable profiles are illustrated, for example, in FIG. 7(b). The hypothetical maximum threshold value is determined by selecting an absolute maximum value and iteratively decreasing that value and deriving corresponding histogram data sets until acceptable row and column histogram profiles are achieved. Similarly, the hypothetical minimum threshold value is determined by selecting an absolute minimum value and iteratively increasing that value and deriving corresponding histogram data sets until acceptable row and column histogram profiles are achieved. Once the hypothetical maximum and minimum threshold values are determined, those values are averaged to determine the defined threshold value that will be used by the feature extraction object 106. Those skilled in the art will appreciate that the defined threshold value may correspond to the maximum hypothetical threshold value, the minimum hypothetical threshold value, or any value that is between those values. Thus, in alternative embodiments, the defined threshold value could be determined, for example, based on a weighted average of the maximum and minimum hypothetical threshold values. In such an embodiment, the defined threshold value may comprise a value corresponding to the sum of the minimum hypothetical threshold value and 2/3 of the difference between the maximum and minimum hypothetical threshold values. 5. The Analysis Object The analysis object 108 analyzes the configuration characteristics of a pupil as a function of time. Preferably, the analysis object 108 receives, as inputs, from the feature extraction object 106 a plurality of data sets for each captured image data frame. The data sets preferably include the time of image capture in msec, x and y coordinates of the pupil center, radius of the flying spot circumference, 48 radii representing the distance between the center and border of the pupil for 48 selected angles within an R,θ coordinate system, and an applied stimulus record for the relevant entry. Upon receiving the input data sets, the analysis object 108 preferably derives at least the following information from the data sets: minimum pupil aperture, maximum pupil aperture, difference between maximum and minimum pupil apertures, latency of pupil response to yellow light stimulus, pupil constriction velocity, first and second pupil dilation velocities and, if desired, pupil irregularity magnitude and location information. Where pupil irregularities are detected, the location of the irregularity preferably is identified by its θ coordinate. However, graphical indications also may be provided on the display 36 of the pupilometer 10. Further, in alternative embodiments, the analysis object 108 may include programming for effecting a multi-varied analysis wherein a plurality of selected variables including, for example, latency indicia, constriction velocity indicia, first and second dilation velocity indicia, segmental static and/or dynamic analysis indicia, constriction/dilation velocity ratio indicia, and maximum and minimum diameter indicia are evaluated for one or both eyes of a patient to arrive at one or more scalar values that are indicative of an overall physiologic or pathologic condition of the patient or, alternatively, to arrive at one or more scalar values that are indicative of an overall opto-neurologic condition of the patient. With regard to the information derived by the analysis object 108, the maximum pupil aperture, minimum pupil aperture and difference determinations require the identification of the maximum pupil aperture and minimum pupil aperture within a set of image data frames and, thereafter, computation of the difference between those values. The latency determination provides an indication in milliseconds of the time that it takes for a pupil to begin to respond to a visible (i.e., yellow) light stimulus pulse. Further, those skilled in the art will appreciate that, when a pupil is exposed to a visual light stimulus pulse, the pupil generally will, after some latency period, constrict and, once the stimulus is discontinued, dilate and return to its original size and configuration. Thus, the analysis object 108 evaluates the response of a pupil to a visual stimulus to determine a pupil constriction velocity and evaluates the response of the pupil to termination of the stimulus to determine first and second dilation velocities. First and second dilation velocities are evaluated because a pupil generally will dilate quickly for a first period of time and, thereafter, will dilate more slowly until its original size and configuration are achieved. Finally, as explained above, an analysis object 108 in accordance with the present invention also preferably identifies any irregularities in the shape of the pupil. Such irregularities may be either static or dynamic in nature. For example, a static irregularity may take the form of an irregular pupil shape in ambient light, whereas a dynamic irregularity may take the form of increased latency for a particular section of the pupil during a response to a the initiation or termination of a visual stimulus. With regard to static irregularities, such irregularities may be identified by identifying the angular orientations of radii that do not fall within prescribed limits, differ from other calculated radii by a predetermined deviation or differ from the fitted radius by a predetermined amount, deviation or percentage. Finally, an analysis object 108 in accordance with the present invention preferably includes programming for identifying statistical anomalies within derived results. This allows an analysis object 108 in accordance with the present invention to discard either actual pupilary response data sets (i.e., fitted radius, center and radii calculations) or derived data sets (i.e., max aperture, min aperture, latency, constriction rate or dilation rates) when a selected value differs from other values by a statistically significant degree. When such anomalies are identified, the relevant data sets are not included in averaging functions, and where many anomalies are identified, an imaging sequence will be invalidated and must be repeated. C. Operation of a Pupilometer in Accordance with the Present Invention Turning now to FIG. 8, operation of a pupilometer 10 in accordance with the present invention proceeds as follows. Generally the pupilometer 10 will be configured according to a default mode of operation. The default mode defines a set of values for basic operation of the device. The defined values may include, for example, values for scan duration, illumination duration and/or profile, stimulus duration and/or profile and stimulus intensity level. However, it will be appreciated that all of the above-listed values may be programmably set under control of the graphic user interface object 100. Thus, it will be appreciated that default programming values generally will be utilized by the pupilometer 10 absent entry of an override by the user in a scan sequence program mode. A typical image acquisition and analysis procedure may proceed as follows. If the pupilometer 10 has been idle for a predetermined period of time (e.g., 120 seconds), the pupilometer 10 is automatically placed in a battery-conserving sleep mode (step 202). By depressing the "scan" button 45 (shown in FIG. 2), the user causes the pupilometer 10 to enter a "ready" mode (step 200). At this time, the user is prompted to enter an alphanumeric subject or patient identification number via the keypad 39 or to download any necessary patient information from a network computer via an infrared data interface, such as an IrDA interface that is provided on numerous conventional personal computer products (step 204). Once any requisite patient identification data has been entered into the system, the user is prompted via the liquid crystal display 36 or an audio prompt to hold down the "scan" button 45 and to position the pupilometer 10 in front of the eye 38 of a subject (step 210). When the user depresses the "scan" button 45, the microprocessor (not shown) initiates an imaging test sequence. The yellow LEDs 26 preferably are not activated during the test sequence. During the test sequence the images that are acquired by the imaging sensor 14 may be displayed on the liquid crystal display (LCD) 36. Preferably, the P-program analyzes the image data frames that are acquired during the test sequence, determines whether or not the pupilometer 10 is properly positioned for obtaining measurements, and determines if all necessary parameters are met to ensure high-quality data recovery. If the test criteria are not met, the user is prompted to reposition the pupilometer 10. After any requisite test criteria are met, the P-program will continue to run the test sequence until the "scan" button 45 is released. Once the scan button 45 is released, the P-program preferably will initiate a prescribed measurement sequence and will activate the illumination system of the pupilometer 10 as needed during the measurement sequence. Upon completion of the measurement sequence, the user is informed via the LCD 36 or an audio prompt that the measurement sequence has been completed (steps 226-228). Following completion of the measurement sequence, the P-program preferably will analyze the image data frames that have been obtained and will display the results of the analysis on the LCD 36. If the results are satisfactory (i.e., are statistically sound), the user may then be prompted to download the results to a printer or related network via the IrDA interface (not shown) (step 246). If the results are not satisfactory, the user is prompted to repeat the measurement sequence (step 222). Finally, after an initial set of measurement are obtained, the user may be prompted for a decision to measure the pupilary characteristics of the other eye of the subject/patient, or the user may be prompted for a decision to make a consensual response measurement (steps 238, 242). The consensual response measurement may take the form of a "swinging flashlight" measurement discussed more fully below. If a consensual measurement is to be performed, the user may be prompted to couple a consensual measurement attachment (shown in FIG. 9) to the pupilometer and to position a yellow LED 52 mounted on the attachment in front of the appropriate eye of the subject/patient. If the consensual measurement attachment is permanently affixed to the pupilometer 10, the user may only need to deploy and/or properly position the attachment. D. Incorporation of Consensual Measurement Apparatus in a Pupilometer in Accordance with the Present Invention Turning now to FIG. 9, a pupilometer 10 in accordance with the present invention may incorporate a consensual measurement apparatus or armature 50 to enable consensual pupilary responses to be analyzed. In a preferred embodiment, the armature 50 may detachably engage a main body 11 of the pupilometer 10. However, as explained above, the armature 50 also may be permanently affixed to the main body 11 of the pupilometer 10. One test for analyzing consensual pupilary responses is commonly referred to within the medical community as a "swinging flashlight test." During a typical swinging flashlight test one eye of a subject is monitored, and a visible light stimulus is applied first to the eye of the patient that is being monitored, then to the eye of the patient that is not monitored and, finally, again to the eye that is monitored. If the eyes of the patient are normal, the pupil of the monitored eye should constrict in response to all of the light stimulus pulses (regardless of which eye the stimulus pulse is applied to). Following application of the first light stimulus, the pupil of the monitored eye should begin to dilate, and upon application of the second light stimulus (i.e., upon application of stimulus to the non-monitored eye), the pupil of the monitored eye should again constrict. If the monitored pupil does not respond adequately to the second stimulus pulse, it may be inferred that the retina of the non-monitored eye somehow may be impaired. If the monitored pupil does not respond adequately to the third stimulus pulse, it may be inferred that the retina of the monitored eye somehow may be impaired. By using a consensual measurement attachment 50 in accordance with the present invention, it is possible to perform a "swinging flashlight" test using the pupilometer 10. For example, the when performing a "swinging flashlight" test, the P-program may first cause the yellow LEDs 26 within the pupilometer 10 to be activated for a period of, for example, 1 second. The P-program then may deactivate the yellow LEDs 26, and 0.5 second following deactivation of the yellow LEDs 26 may activate for 0.5 second the yellow LED 52 located at the distal end 54 of the consensual attachment. Finally, after deactivating the yellow LED 52 and waiting for a period of, for example, 0.5 second, the P-program may again activate the yellow LEDs 26 for a period of 1 second. Image frames may be obtained by the imaging sensor 14 at a rate of, for example, 10 frames per second and for a total period of 5.0 or more seconds to evaluate the consensual response of the imaged eye. If desired, the process may be repeated a predetermined number of times. E. Miscellaneous System Calibration and Pupil Identification Processing Techniques In alternative embodiments, the P-program of a pupilometer 10 in accordance with the present invention may incorporate a calibration algorithm that uses acquired data descriptive of the perimeter of the iris 37 of the eye 38 of a patient to define a relationship between pixel spacing data and real world measurement parameters and/or to evaluate an orientation of a patient's eye 38 in relation to the pupilometer 10. For example, in one innovative aspect, the P-program of a pupilometer 10 may cause the iris of the eye of a patient to be illuminated by blue light (i.e., may activate the blue LED 28) and, while the patient's eye is so illuminated, may obtain an image of the sclera/iris border of the patient's eye. A flying spot or similar processing algorithm may then be used to identify a best fitting elliptical circumference for the sclera/iris border of the patient's eye, and the radii or horizontal and vertical diameters of the circumference may be compared to or correlated with assumed sclera/iris border radii or diameters to provide a correlation between a pixel count and a real world measurement. For example, if the horizontal diameter of a sclera/iris border is assumed to be 11.7 mm, and the sclera/iris border measures 117 pixels in diameter, the P-program of the pupilometer 10 may derive a pixel measurement to real world correlation factor of 10 pixels/mm, and that correlation factor may be used to provide the user with pupil measurement information. In accordance with one preferred form of the present invention, the horizontal diameter of the sclera/iris border is assumed to be 11.75 mm for in all subjects. However, those skilled in the art will appreciate that a different diameter, such as 11.0 mm or 12.0 mm, may also be assumed. Similarly, by evaluating the shape of the sclera/iris border of an eye it is possible to estimate the angular orientation of the eye with respect to the pupilometer 10 and, moreover, to evaluate the orientation of an eye with relation to a vertical axis of the eye. Preferably, this may be done by evaluating a degree of ellipticity of the imaged sclera/iris border and assuming that the shape of the sclera/iris border has a predetermined elliptical shape. Such, measurements may be further refined by comparing the shape of a pupil to the shape of a surrounding sclera/iris border to determine whether variations in the shape of a pupil arise from angular orientation of the eye in relation to the pupilometer 10, or from non-uniformities or irregularities in the perimeter of the pupil. In another innovative aspect, a pupilometer 10 in accordance with the present invention may include software for utilizing physical landmarks to assist in locating a pupil within an image data frame. In such an embodiment, the feature extraction object 106 of the P-program executed by the microprocessor (not shown) may include code for identifying characteristic structures of ocular tissue such as eyelids and/or eyelashes within an image data frame, and for using the location of those structures to predict the location of a pupil within the image data frame. Additional landmarks that may be located in accordance with the present invention include the lachrymal punctum, lachrymal caruncula, and lateral and medial papebral commisures of a patient's eye. These landmarks also may be used to identify which eye of a patient is being monitored. F. Diagnostics Systems and Methods in Accordance with the Present Invention In still another innovative aspect, the present invention is directed to improved diagnostics systems and methods incorporating a pupilometer 10 and medical database (not shown). For example, it is contemplated in accordance with the present invention that data representative of a plurality of pupilary response or configuration characteristics associated with one or more physical or pathological conditions may be stored within a medical diagnostics data base, that a pupilometer 10 may be used to obtain data descriptive of one or more pupilary response or configuration characteristics from a patient, and that the obtained data may be compared to the stored data within a data analysis system to identify one or more physiologic or pathologic characteristics or conditions of the patient. Further, in a preferred form, the obtained and/or stored pupil configuration data may be descriptive of one or more static or dynamic regional non-uniformities that may exist within the perimeter of a patient's pupil. While the invention is susceptible to various modifications and alternative forms, specific examples thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the invention is not to be limited to the particular forms or methods disclosed, but to the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the appended claims.

A pupilometer having a pupil irregularity or non-uniformity detection capability. The pupilometer may comprise an imaging sensor for generating signals representative of a pupil of an eye, a data processor; and a program executable by the data processor for enabling the data processor to process signals received from the imaging sensor and to thereby identify one or more regions of non-uniformity within an image of a perimeter of the pupil. The pupilometer may incorporate several innovative calibration and thresholding routines and may provide the basis for an innovative medical diagnostics system, when coupled to a network containing a suitable medical database and data processing hardware.

CLAIM TO PRIORITY [0001] The present invention claims priority to U.S. Provisional Application No. 60/551,262, filed Mar. 8, 2004, entitled, “METHODS AND APPARATUS FOR IMPROVED DRILLING AND MILLING TOOLS FOR RESECTION,” and U.S. Provisional Application No. 60/551,080, filed Mar. 8, 2004, entitled, “METHODS AND APPARATUS FOR PIVOTABLE GUIDE SURFACES FOR ARTHROPLASTY,” and U.S. Provisional Application No. 60/551,078, filed Mar. 8, 2004, entitled, “METHODS AND APPARATUS FOR MINIMALLY INVASIVE RESECTION,” and U.S. Provisional Application No. 60/551,096, filed Mar. 8, 2004, entitled, “METHODS AND APPARATUS FOR ENHANCED RETENTION OF PROSTHETIC IMPLANTS,” and U.S. Provisional Application No. 60/551,631, filed Mar. 8, 2004, entitled, “METHODS AND APPARATUS FOR CONFORMABLE PROSTHETIC IMPLANTS,” and U.S. Provisional Application No. 60/551,307, filed Mar. 8, 2004, entitled, “METHODS AND APPARATUS FOR IMPROVED CUTTING TOOLS FOR RESECTION,” and U.S. Provisional Application No. 60/551,160, filed Mar. 8, 2004, entitled, “METHODS AND APPARATUS FOR IMPROVED PROFILE BASED RESECTION,” and U.S. patent application Ser. No. 11/036,584, filed Jan. 14, 2005, entitled, “METHODS AND APPARATUS FOR PINPLASTY BONE RESECTION,” and U.S. patent application Ser. No. 11/049,634, filed Feb. 3, 2005, entitled, “METHODS AND APPARATUS FOR WIREPLASTY BONE RESECTION,” which claims priority to U.S. Provisional Application No. 60/536,320, filed Jan. 14, 2004, and U.S. patent application Ser. No. 11/049,634, filed Feb. 3, 2005, entitled, “METHODS AND APPARATUS FOR WIREPLASTY BONE RESECTION,” which claims priority to U.S. Provisional Application No. 60/540,992, filed Feb. 2, 2004, entitled, “METHODS AND APPARATUS FOR WIREPLASTY BONE RESECTION,” the entire disclosures of which are hereby fully incorporated by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] This invention generally relates to methods and apparatus for bone resection to allow for the interconnection or attachment of various prosthetic devices with respect to the patient. More particularly, the present invention relates to methods and apparatus for improved drilling and milling tools for resection and arthroplasty. [0004] 2. Background Art [0005] Different methods and apparatus have been developed in the past to enable a surgeon to remove bony material to create specifically shaped surfaces in or on a bone for various reasons including to allow for attachment of various devices or objects to the bone. Keeping in mind that the ultimate goal of any surgical procedure is to restore the body to normal function, it is critical that the quality and orientation of the cut, as well as the quality of fixation, and the location and orientation of objects or devices attached to the bone, is sufficient to ensure proper healing of the body, as well as appropriate mechanical function of the musculoskeletal structure. [0006] In total knee replacements, for example, a series of planar and/or curvilinear surfaces, or “resections,” are created to allow for the attachment of prosthetic or other devices to the femur, tibia and/or patella. In the case of the femur, it is common to use the central axis of the femur, the posterior and distal femoral condyles, and/or the anterior distal femoral cortex as guides to determine the location and orientation of distal femoral resections. The location and orientation of these resections are critical in that they dictate the final location and orientation of the distal femoral implant. It is commonly thought that the location and orientation of the distal femoral implant are critical factors in the success or failure of the artificial knee joint. Additionally, with any surgical procedure, time is critical, and methods and apparatus that can save operating room time, are valuable. Past efforts have not been successful in consistently and/or properly locating and orienting distal femoral resections in a quick and efficient manner. [0007] The use of oscillating sawblade based resection systems has been the standard in total knee replacement and other forms of bone resection for over 30 years. Unfortunately, present approaches to using existing planar or non-planar saw blade instrumentation systems all possess certain limitations and liabilities. [0008] Perhaps the most critical factor in the clinical success of any bone resection for the purpose of creating an implant surface on the bone is the accuracy of the implant's placement. This can be described by the degrees of freedom associated with each implant. In the case of a total knee arthroplasty (TKA), for example, for the femoral component these include location and orientation that may be described as Varus-Valgus Alignment, Rotational Alignment, Flexion-Extension Alignment, A-P location, Distal Resection Depth Location, and Mediolateral Location. Conventional instrumentation very often relies on the placement of ⅛ or 3/16 inch diameter pin or drill placement in the anterior or distal faces of the femur for placement of cutting guides. In the case of posterior referencing systems for TKA, the distal resection cutting guide is positioned by drilling two long drill bits into the anterior cortex across the longitudinal axis of the bone. As these long drills contact the oblique surface of the femur they very often deflect, following the path of least resistance into the bone. As the alignment guides are disconnected from these cutting guides, the drill pins will “spring” to whatever position was dictated by their deflected course thus changing their designated, desired alignment to something less predictable and/or desirable. This kind of error is further compounded by the “tolerance stacking” inherent in the use of multiple alignment guides and cutting guides. [0009] Another error inherent in these systems further adding to mal-alignment is deflection of the oscillating sawblade during the cutting process. The use of an oscillating sawblade is very skill intensive as the blade will also follow the path of least resistance through the bone and deflect in a manner creating variations in the cut surfaces which further contribute to prosthesis mal-alignment as well as poor fit between the prosthesis and the resection surfaces. Despite the fact that the oscillating saw has been used in TKA and other bone resection procedures for more than 30 years, there are still reports of incidences where poor cuts result in significant gaps in the fit between the implant and the bone. Improvements in the alignment and operation of cutting tools for resecting bone surfaces are desired in order to increase the consistency and repeatability of bone resection procedures as is the improvement of prosthetic stability in attachment to bone. [0010] One technique that has been developed to address these challenges has been the profile based resection (PBR) techniques taught, for example, by U.S. Pat. Nos. 5,514,139, 5,597,397, 5,643,272, and 5,810,827. In a preferred embodiment of the PBR technique, a side cutting tool such as a milling bit or side drill bit is used to create the desired resected surface. While the PBR technique offers many advantages over conventional resection and arthroplasty techniques, it would be desirable to provide enhancements to the PBR technique that improve the ability to address soft tissue management SUMMARY OF THE INVENTION [0011] The present invention provides for embodiments of milling and drilling tools and soft tissue management techniques for arthroplasty facilitating intraoperative and postoperative efficacy and ease of use. In one embodiment, resiliently biased soft tissue protective sleeves surround the side cutting tool and are interposed along the longitudinal axis of the side cutting tool adjacent each side of the bone. The soft tissue protective sleeves are biased to track along the contour of the side of the bone and prevent the side cutting tool from being exposed to soft tissue during the resection. In another embodiment, a pilot drill is initially utilized to create an initial bore in the bone to be resected. The pilot drill preferably has an end cutting arrangement and a non-cutting removal channel that minimizes the tendency of the pilot drill bit to drift off-axis as the initial bore in the bone is created. Once the initial bore is created, the pilot drill bit is withdrawn and a second side cutting tool, such as a milling bit, is then inserted into the bore to perform the desired surface resection. [0012] The present invention utilizes a number of embodiments of cutting tools to remove boney material to create cut surfaces for prosthetic implant attachment and fixation. The overriding objects of the embodiments are to provide the ability to perform resection in very small incisions, the creation of precise and accurate cut(s), and to provide for soft tissue protection characteristics and features preventing the tool from accidentally harming soft tissue. Specifically, many of the cutting tool embodiments disclosed are either incapable or highly resistant to damaging soft tissue, or are by means disclosed prevented from coming into contact with soft tissue in the first place. [0013] The present invention utilizes a number of embodiments of cutting guide technologies loosely or directly based on Profile Based Resection (PBR). The overriding objects of PBR technologies are to provide for significantly improved reproducibility of implant fit and alignment in a manner largely independent of the individual surgeon's manual skills, while providing for outstanding ease of use, economic, safety, and work flow performance. [0014] The present invention utilizes a number of embodiments of alignment or drill guides to precisely and accurately determine the desired cutting guide location/orientation, thus cut surface location(s)/orientation(s), thus prosthetic implant location and orientation. The overriding objects of the embodiments are to precisely and accurately dictate the aforementioned locations and orientations while optionally enabling ease of use in conjunction with manually or Computer Assisted techniques, and while optionally enabling ease of use in minimally invasive procedures where surgical exposure and trauma are minimized. [0015] The present invention utilizes a number of methods and apparatus embodiments of soft tissue management techniques and the devices supporting said techniques. The overriding object of these embodiments is to take advantage of the anatomy, physiology, and kinematics of the human body in facilitating clinical efficacy of orthopedic procedures. [0016] It is an often repeated rule of thumb for orthopedic surgeons that a “Well placed, but poorly designed implant will perform well clinically, while a poorly placed, well designed implant will perform poorly clinically.” The present invention provides a method and apparatus for reducing implant placement errors in order to create more reproducible, consistently excellent clinical results in a manner that decreases risk to soft tissue, incision or exposure size requirements, manual skill requirements, and/or visualization of cutting action. [0017] It should be clear that applications of the present invention is not limited to Total Knee Arthroplasty or the other specific applications cited herein, but are rather universally applicable to any form of surgical intervention where the resection of bone is required. These possible applications include, but are not limited to Unicondylar Knee Replacement, Hip Arthroplasty, Ankle Arthroplasty, Spinal Fusion, Osteotomy Procedures (such as High Tibial Osteotomy), ACL or PCL reconstruction, and many others. In essence, any application where an expense, accuracy, precision, soft tissue protection or preservation, minimal incision size or exposure are required or desired for a bone resection and/or prosthetic implantation is a potential application for this technology. In addition, many of the embodiments shown have unique applicability to minimally invasive surgical (MIS) procedures and/or for use in conjunction with Surgical Navigation, Image Guided Surgery, or Computer Aided Surgery systems. BRIEF DESCRIPTION OF THE DRAWINGS [0018] Other important objects and features of the invention will be apparent from the following detailed description of the invention taken in connection with the accompanying drawings in which: [0019] FIGS. 1, 2 , and 3 are pictorial representations standard incision sizes or exposure required by the prior art, while [0020] FIG. 4 is a pictorial representation or approximation of one form of surgical exposure that is desired. [0021] FIGS. 5-98 , 111 , 119 , and 125 - 127 show various depictions of embodiments and methods in accordance with alternate embodiments of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0022] It should be noted that, in many of the figures, the cut surface created by the cutting tool in accordance with the techniques of the present invention are shown as having already been completed for the sake of clarity. Similarly, the bones may be shown as being transparent or translucent for the sake of clarity. The guides/pins, cutting tool, bones, and other items disclosed are may be similarly represented for the sake of clarity or brevity [0000] FIGS. 1 through 4 [0023] FIGS. 1 and 2 show conventional surgical exposures and instrumentation being utilized. FIG. 4 shows a reduced incision currently utilized in performing the current state of the art in ‘minimally invasive’ Unicondylar Knee Replacement. [0000] FIGS. 41-60 [0024] FIGS. 41 through 60 represent an embodiment of the present invention the soft tissue protection sleeves and milling/drilling bit management techniques that enable Triple Transcutaneous Transarticular TKA (“TTTKA” or “Triple TKA” or “T Cubed” or “T 3 ” Procedures). The soft tissue protection sleeves shown, for example, in FIGS. 42 and 43 . One clinical application calling for the benefits of this feature would be where a PBR cutting guide, as generally shown in FIG. 35 is positioned completely outside of the wound with the exception of fixation features which extend from the externally located guides through skin incisions and into holes or apertures created in bone. As shown in FIGS. 52 and 53 , the cutting tool, in the case of the present invention a side cutting drill, is extended through the handle, the guide, the skin, fat, capsule, etc (soft tissue), across, across and in front of, through, or beneath the articular surfaces of the joint, and through the soft tissue, guide, and handle on the opposing side of the bone. The soft tissue protection sleeves may be extended through the soft tissue and into contact with the sides of the bone. The retaining lip can be used to maintain the sleeves in contact with the bone and are held there by the edges of the incision through the capsule during cutting. The springs shown in FIG. 43 can further bias the sleeves into contact with bone in a manner that would maintain that contact as the width of the bone changed along the cutting path of the resected surface. [0025] One skilled in the art will note that the thicknesses for the soft tissue through which the sleeves extend change significantly from patient to patient thus requiring the proportions of the sleeve, spring and other components of the present embodiment of the invention to change accordingly. For example, in an obese patient, the fat layer through which the cutting tool extends can be 5 inches thick per side or more. The diameter of the soft tissue protection sleeve can be significantly reduced with respect to what is shown as the side cutting drill diameter is reduced, thus requiring a smaller capsular or other soft tissue incision or ‘stab wound’. [0026] In operation, the handle is manipulated to traverse the cutting path of the cutting guide while the tibia is swung through a range of motion about the femur as shown in comparing FIGS. 54 through 60 . This particular principal of operation takes advantage of the fact that the capsule, the patella, and to a lesser or greater extent the skin, moves with the tibia as it moves through a range of motion with respect to the femur. Thus, a small, perhaps 4 mm to 10 mm long stab wound through skin to the medial side of the posterior femoral condyles (roughly in line with the axis of the pilot drill shown in FIG. 51 ) with the knee bent in flexion, and then looked at the side of the femur (through the portal created by the stab wound) while moving the tibia through a range of motion, the side of the femur would be observed to be passing by/through the portal. In order to complete all of the resected surfaces on the femur necessary to fix a standard femoral prosthesis, it may be necessary in one embodiment to make two passes with the side cutting drill sweeping about the femur with the tibia as represented in FIGS. 54 through 60 . [0027] FIGS. 44 through 51 represent an embodiment of the present invention for use in creating pilot holes allowing for introduction of a side cutting drill or other cutting tool in Triple TKA or Unicondylar or Bicondylar procedures. Of particular interest, the pilot drill is designed to eliminate or mitigate any deviations of the drill from its intended location and orientation as it is guided to create portals in living bone. Standard drills tend to follow the path of least resistance into and through bone often resulting in either poor drill placement, and thereby poor cutting guide placement, or improperly located and oriented portals or apertures for fixation of a cutting guide resulting in poor cutting guide placement. As shown in FIG. 44 , the pilot drill possesses cutting teeth that are very aggressive in side cutting. This is critical in that it prevents deflection of the cutting tool when it contacts tissue of varying material properties. This area of very aggressive side cutting teeth is relatively short, and is followed by a longer smooth portion of the shaft of the drill which is designed to be incapable of cutting bone, but may beneficially include smooth flutes allowing for removal of chips during the cutting process. A pilot drill of this kind, optionally used in conjunction with the Surg Nav Drill Guide of FIGS. 8 through 11 , would be outstanding for use in creating the apertures in bone desired for positioning any number of cutting guides. Specifically, the pilot drill may provide sufficient accuracy and precision of aperture creation to allow for drilling all the way through or across a bone to which a cutting guide will be attached to bone sides of the aperture as shown in FIG. 68 , where the cancellous bone within the cortical shell is not shown for the sake of clarity. [0028] In use with the embodiment of the present invention, with the soft tissue protection sleeves of the milling handle in contact with a bone surface, the pilot drill would be plunged through the bushings of the milling handle and across the joint, as shown in FIGS. 45 through 51 . FIG. 51 represents the pilot drill having been plunged entirely across the joint, but with the milling handle not shown for the sake of clarity. Thus, a portal has been created across the entirety of the joint for subsequent insertion of the side cutting drill shown in FIGS. 52 and 53 , or any other cutting tool. It should be noted that in embodiments adapted for use in Unicondylar knee replacement, it would only be necessary to create the portal in one side of the joint for extension of the cutting tool across only a single condyle (as is seen in comparing FIGS. 78 and 80 ). An alternative embodiment and method of the milling handle of the present invention represented in FIG. 54 would be to extend the side cutting drill, or other cutting tool, through a soft tissue portal on one side of the joint, across the entirety of the bone surfaces to be resected or cut, but not extend the tool through the soft tissue on the far side of the joint. As control of the side cutting drill by the milling handle is very robust, even when it supports only one spindle of the side cutting drill, accurate and precise preparation of the distal femur can be performed without necessitating a second soft tissue portal, and the soft tissue trauma associated with it, no matter how minor, on the far side of the joint. [0029] Alternatively, a hybrid embodiment of externally and internally located guide surfaces would allow for high precision, high accuracy cutting without necessitating the creation of soft tissue portals for insertion of the cutting tool. This embodiment of the present invention can be attained by positioning one PBR cutting guide surface(s) in the wound (perhaps looking like the medial guide surface of the cutting guide shown in FIGS. 68 through 70 ) and interconnecting it with an externally located PBR cutting guide surface(s) (for example, looking like the laterally located plate in FIG. 60 ). This would allow for single spindle guidance of the side cutting drill or other cutting tool in a very robust manner, while minimizing the trauma to soft tissues necessary to implement these embodiments. Furthermore, the use of these single spindle embodiments lend themselves to easy manipulation of the cutting tool in pivotally sweeping (see FIG. 85 ) a cut surface while manipulating the cutting tool axially with respect to the milling handle. Thus the anterior chamfer cut, distal cut, and posterior cut could be completed by sweeping the cutting tool along the cutting path of the cut surface, and the anterior and/or posterior cuts could be completed by pivotally sweeping the cutting tool as mentioned above while maintaining the stability inherent in guiding the milling handle on guide surfaces on opposing sides of the cut being created. This is beneficial in that the internally located guide surfaces could be truncated or shortened significantly allowing for both easier insertion into the surgical exposure and reduction in the exposure necessary to accommodate the embodiments in clinical use. [0000] FIGS. 5 through 11 [0030] FIGS. 5 through 11 concentrate on alignment guide and/or drill guide techniques. FIG. 5 shows a manually operated alignment guide suitable for use with surgical exposures similar to that shown in FIG. 2 (it should be noted that surgical navigation sensors could be used to assist in determining final drill guide location and orientation). FIGS. 6 and 7 show an improvement upon the embodiment shown in FIG. 5 for enabling manual alignment guide use in less invasive incisions by providing soft tissue accommodating contours or reliefs. In other words, for a medial parapatellar incision, the alignment guide is configured to allow for appropriate contact and referencing of the distal and posterior femoral condyles, the IM canal (when not relying on an extramedullary reference or inference of the mechanical axis) or IM Rod, the anterior cortex or anterior runout point of a given or proposed implant size (via a stylus not shown), and the epicondylar axis via palpitation or visual reference while the patellar tendon, patella, and/or quadriceps tendon is draped over the lateral side (right side as shown in the figures) of the alignment guide allowing insertion of the guide when the patella is neither everted not fully dislocated as in conventional techniques. It should be noted that initial alignment indicated by reference of the distal femur may be further adjusted in all six degrees of freedom as a fine tuning for final cut location and orientation. This simply calls for the inclusion of additional adjustment of the location and orientation of the crossbar mechanism and/or rotational alignment arm, with respect to the initial reference provide for by contact between the body of the guide and the bone (optionally including the IM Rod), in flexion-extension angulation, varus-valgus angulation (rotational angulation and Anterior-Posterior location are already shown), mediolateral location (represented in this embodiment of the current invention by the cross bar mechanism in FIG. 5 where drill guide mediolateral location is shown as being independently and infinitely adjustable), and proximal-distal location (as shown in FIGS. 5, 6 , and 7 —it should be noted that this adjustment might be best embodied in an infinitely adjustable slide as opposed to the incrementally adjustable slide shown, and that simple marking would be present indicating the relative movement of the slide with respect to the body). It may be desirable to only utilize only a medial drill guide plate with multiple drill guide bushings to create holes extending partially or completely across the femur depending upon the manner in which the guides are to be connected to the femur. [0031] FIGS. 8, 9 , and 10 show an alternative alignment/drill guide embodiment of the present invention wherein a cannulated surgically navigated handle/drill guide is used to create fixation apertures in the bone for direct or indirect fixation of a cutting guide. As shown in FIG. 8 , it may be advantageous to include tines for penetrating the bone to obtain initial stabilization of the handle in the location and orientation indicated by the surgical navigation system (“Surg Nav”—this term shall be used interchangeably with Computer Aided Surgical System or Image Guided Surgical System throughout this disclosure) prior to extending the drill, represented in FIG. 10 , into the bone to create the aperture. It should be noted that the aperture, or hole, thus created could be blind or extended to a specific depth, or optionally extended entirely through the bone and out the furthest side of the bone. Importantly, this process could be utilized transcutaneously through a small stab wound (perhaps 4 mm in length) through the skin to the bone surface, or through a preformed incision through which other instrumentation of the present invention or other devices may be introduced during a procedure. Further, although only one cannulation is shown, a single handle may desirably contain multiple cannulations, some or all of which could be adjustably extended into contact with the bone to reduce any wandering of the drill contacting oblique bone surfaces and improve the precision and accuracy of aperture creation (thus allowing for the creation of apertures in the medial side of the femur, represented in FIG. 11 , with a single Surg Nav Handle—Also, the apertures may be configured such that the femoral and tibial apertures shown in FIG. 11 are all created using a single positioning step for the handle). As represented in FIG. 9 , there is very little distance over which the drill is cantilevered between its guidance within the cannulations and its point of initial contact with the outer surface of the bone. This aspect of this embodiment of the current invention is critical in preserving the potential accuracy of Surg Nav systems, i.e.; the navigation system (the computer and the sensors) may be capable of determining appropriate location and orientation to ±0.1 mm and ±0.5 degrees, but if the location and/orientation of the aperture created represents some path of least resistance in bone which is followed by the drill, the resultant location and orientation of cut surfaces, and thereby the location and orientation of the prosthesis attached thereto, will likely be seriously in error. [0032] It should also be noted that the methods described herein are applicable to the methods demonstrated in Provisional Patent Application Ser. No. 60/536,320, entitled “Methods and Apparatus for Pinplasty Bone Resection” and Ser. No. 60/xxx,xxx, entitled “Methods and Apparatus for Wireplasty Bone Resection,” the disclosures of each of which are hereby incorporated by reference. [0033] It should also be noted that another embodiment of the present invention, represented in FIGS. 88-92 , benefits from the apparatus and principles of operation outlined above. As shown in FIG. 88 , an aperture and a plane are created in bone which actually act as the cutting guide in controlling the location and orientation of the cutting tool within a specific plane during the creation of a cut surface. In this embodiment of the present invention, the cannulated drill guide will, in either manual or Surg Nav techniques, be used to guide a forstner style drill bit (the ‘guide surface’ shown in FIG. 88 could have been created by a modified drill with a leading section 15 mm long by 4 mm in diameter, responsible for the pivot aperture, and a 10 mm diameter following section which was about 10 mm long, responsible for the pivot reference surface) to create a larger diameter cylindrical aperture the bottom of which would define a pivot reference surface parallel to the cut surface to be created, and a smaller diameter cylindrical aperture to form a pivot aperture for maintaining the body of the bushing shown in FIGS. 88-91 in the proper location and orientation while cutting. Importantly, the technique outlined above is beneficially applied to tibial resection or any other planar or curvilinear resection technique as well. [0000] FIGS. 12 through 34 [0034] FIGS. 12-34 disclose embodiments of the present invention for creating planar and/or curvilinear resection surfaces on or in the proximal tibial and other bones and embodiments of the present invention for prosthetic implants. [0035] FIGS. 12-15 represents an embodiment of the present invention for cutting guides and cutting tools which substantially comprises a guide with guide pivot aperture(s) and a guide pivot reference surface(s) for mating with a bushing controlling a cutting tool, wherein the bushing possess a bushing reference plane (which mates with the pivot reference surface(s) of the guide), a bushing pivot pin, best represented in FIG. 88 (which mates with the guide pivot aperture(s) of the guide), and a cannulation for articulated and/or axial guidance of the cutting tool. [0036] There are a number of optional features that are highly desirable depending on the preferred method of use utilized for these embodiments of the present invention. The soft tissue protection tip of the cutting tool and the integral soft tissue retractor feature of the bushing body are two principal examples represented in FIG. 20 . The soft tissue protection tip can be integrally formed as a part of the cutting tool during its manufacture, be a separate component attached to it, and may, in one preferred embodiment, be free to rotate with respect to the cutting tool (which would be useful in preventing rotating bearing contact between the tip and soft tissue). The integral soft tissue protector in beneficial in preventing or mitigating contact between soft tissue near the area where the cutting tool enters, cuts, and exits the wound (in other words, to the right and left of the bushing body shown in FIG. 13 ). If you picture the incision as being a window into the joint which is somewhat elastically moveable from side to side, the integral soft tissue retractor would act to shift that window to mitigate or prevent contact between the soft tissue (specifically the patella tendon, medial or lateral collateral ligaments, the capsule, skin, fat, etc.) and the cutting surfaces of the cutting tool. [0037] In operation, the guide is properly positioned with respect to the proximal tibia and the cut to be created thereon and robustly fixed with respect to the tibia or directly to the tibia. This can be accomplished by manual alignment means outlined in U.S. Pat. No. 5,643,272 for manually positioning guides then fixing them in place, or use the '272 apparatus and methods to create the fixation apertures shown in FIG. 11 or 12 , or use the Surg Nav techniques described herein as shown or in conjunction with the methods described in the '272 patent. The bushing body is then engaged with the guide. Three primary methods of initiating cutting of the proximal tibia are preferred. The first, or ‘Tangent Method’, is initiated by extending the side cutting drill through the bushing body cannulation and into contact with a side of the tibia and then sliding the optional non cutting tip along the face of the bone until the cutting surfaces of the cutting tool were first in contact with the side of the bone. At this point, the cutter could be actuated to begin cutting the boney tissue to create the cut surface. As the non-cutting tip cannot cut bone, its edges would remain at all times immediately beyond and adjacent to the boundary of the cut surface being created. The diameter or size may be greater or less than the diameter or size of cutting surfaces of the cutting tool. Note that although the embodiment of the cutting tool shown is a side cutting drill, a modified rat tail rasp driven by a reciprocating driver could also work well—any cutting tool capable of cutting in a direction orthogonal to its long axis is considered to be within the scope of the present invention. [0038] As best represented in FIG. 15 , the entirety of the resected surface may be prepared in this manner. The second primary method is the ‘Plunge Then Sweep’ method. In this method, the cutting tool or optionally a pilot drill would be plunged completely or partially across the surface to be cut. Then the cutting tool could be swept back and forth in clockwise and counter-clockwise directions while being axially manipulated to complete the cuts. The third primary method is the ‘Chop Then Sweep’ method represented in comparing FIGS. 88 and 89 . In this method, the cutting surfaces of the cutting tool are positioned over and at least partially across the uncut bone, then chopped down into it by manipulating the bushing. In other words, the bushing pivot pin is engaged with the pivot aperture with the cutting tool positioned over the bone which positions the bushing reference surface at a distance above the pivot reference surface, then the bushing is moved downward along the axis of the bushing pivot pin while the cutting tool is under power until the cutting tool reaches the cut surface to be created (if the cutting tool is a side cutting drill, the cutting surfaces would be tangent to the desired cut surface at that time). The bushing is then manipulated as described hereinabove to complete the cuts. Importantly, the pivot reference surface and pivot aperture could be slidably mounted to a base component fixed with respect to the tibia so that the surgeon may manipulate the bushing body to simultaneously create the cut and move the pivot aperture with respect to the tibia. This embodiment will enable the surgeon to easily compensate for any soft tissue condition encountered clinically while preserving the benefits of the present invention. Methods combining the aforementioned primary methods are considered to be within the scope the present invention. Importantly, most standard or prior art tibial resection cutting guides may be simply modified to include the pivot apertures described herein. [0039] FIGS. 16 through 21 describe another embodiment of the present invention. As shown in FIG. 16 , this embodiment includes a Base and a Rotational/Translational Pivot Arm coacting to allow for infinite manipulation of the bushing pivot pin location within a desired plane during the process of removing material from the proximal tibia or other bone. Movement of the Rotational/Translational Pivot Arm in both rotational and translational degrees of freedom within a desired plane allows for any combination of rotational and translational movement of the axis of the bushing pivot pin within its desired plane. In other words, this embodiment of the present invention allows for infinite and continuous adjustability of cutting tool location and orientation with respect to the bone or bones being cut while providing for accurate and precise cut surface creation. [0040] FIGS. 22 through 28 represent another embodiment of the present invention whose principal of operation are similar to previous embodiments, with the exception of including a depth limiting contour which acts as either a definitive limitation for cutting tool depth or as a general guideline for a surgeon to follow as the patient's clinical presentation and the surgeon's judgment dictate. Although the embodiment shown is directed toward Unicondylar tibial preparation, it should be noted the any clinical application where such definitive or guideline type depth guidance is desirable. [0041] FIGS. 29 and 30 show an embodiment of the present invention directed toward endplate preparation in spinal reconstruction where the endplates are prepared to receive a prosthetic implant. It is interesting to note that the profile of the cutting path of the guide represented in FIG. 30 , in this embodiment, is geometrically identical to the cutting path of the resected surface created by the passage of the cutting tool shown. This could be very helpful in clinical application where such a device where inserted into a wound such that, while the surgeon could not visually observe the cutting tool while it removes boney material, he could, by way of the guide geometry, observe where the cutting is with respect to the bone being cut by looking at the position (represented by “POS 1 ” and “POS 2 ”) of ‘Pivot 2 ’, represented in FIG. 30 , with respect to its location in contact with the guide as it traverses the cutting path of the cutting guide. This embodiment is also highly applicable to tibial resection and could allow for cut geometries that are anatomically curved in both AP and ML profiles to both preserve bone and improve fixation quality and load transfer characteristics between the implant and the bone by converting the shear component load of conventional planar tibial components into compressive loads via geometrically normal or transverse abutment of bone and implant surfaces in the direction of A-P and/or M-L and/or torsional shear loading. An implant design embodying fixation geometries for mating with such cut surfaces is highly desirable. In one embodiment of such a tibial prosthesis design, the fixation surfaces would be intended to mate, directly or indirectly, with cut surfaces represented in FIGS. 33 and/or 34 (the tibia in the right side of the FIG. 34 ). In essence, the tibial implant would possess a planar or gently curvilinear ‘rim’ for contacting the ‘cortical skim cut’ surface (represented in FIG. 32 ), and convex fixation surfaces for direct or indirect fixation to the concave tibial cuts represented in FIGS. 33 and 34 . Direct fixation to such surfaces could be achieved by high precision resection of both the cortical rim, for attachment of the rim of the tibial prosthesis, and the concave surface(s), for intimate apposition to the convex implant surfaces. Such fixation, specifically of the concave bone cuts to the convex implant surfaces, could be achieved by way of an interference fit between the cuts and the implant along one axis (for instance, a front to back—AP—axis or direction), or along two axes (for instance, AP and Side to Side—ML—axes), or circumferentially (in other words a bit like a pin of a given diameter being forced into a hole of a lesser diameter), or both circumferentially and along an axis at roughly a 90 degree angle or normal to the skim cut surface when viewed in one or two orthogonal planes (an “up and down axis” or superior-inferior or proximal distal direction). It should be noted that an interference fit in a roughly superior-inferior direction may call for a textured surface on the bottom most surface of the convex fixation surfaces presents a small surface area of contact at initial contact with the bottom of the concave cut to allow the implant to compact a reduced area of cancellous bone as the implant is impacted in a superior to inferior direction until it reaches its desired superior-inferior location and/or contact between the rim of the implant and the skim cut of the cortices. As compared to previous methods of achieving implant fixation, these embodiments of the present invention yield superior stability of implant fixation to bone to an extent reminiscent of the difference between riding a horse wearing a deeply dished saddle and riding a very sweaty horse bareback. [0042] An alternative fixation paradigm allows for less intensive demands for the precision of the fit between concave tibial cuts and convex fixation surface. In essence, the concave surface may be ‘excavated’ in any desired manner (such as the Cutting Trials shown in FIG. 31 which cut the proximal tibia while the tibia is moved through at least a portion of its range of motion about the femur), and a morselized or granular osteobiological substance, perhaps tricalcium phosphate, HATCP, or other substances generally described as ‘bone substitutes’ or autograft or allograft cancellous or cortical bone (it would be very useful to use the bone which was removed from the tibia or other patient bone during the creation of the cut(s) in that it is readily available and completely avoids the issues of disease transmission or immune response), is then impacted into the concave surface using a ‘form’ to create a surface of impact material (referred to herein as the “Impacted Surface”) of specific shape and location/orientation with respect to the cortical skim cut and/or the tibia or femur. This form is beneficially shaped in a manner related to the shape of the convex implant fixation surface shape so as to create a specific geometric relationship between the implant fixation surfaces and the Impacted Surface geometry. In one embodiment of the present invention, the fit between the implant and the Impacted Surface would be an interference fit or press fit. As properly impacted morselized cancellous bone is known to achieve stiffnesses (or modulus of elasticity) which approach as much as 80% of the stiffness of cortical bone in compression, robust intraoperative fixation may be achieved in this manner. In another embodiment, the fit would leave a significant gap, perhaps 0.2 mm to 4.0 mm in width, between portions or all of the convex fixation surfaces of the implant and the convex cut(s), into which bone cement or other substance would then be injected or impacted achieving interdigitation with both the surfaces of the prosthesis and the material of the Impacted Surface. This results in what could be described as composite interface of both biologically active and non-living but structurally robust materials to facilitate both immediate intraoperative stability by way of simple mechanics and long term stability by way of improved load transfer between the implant and the bone eliciting a beneficial biological response by the bone to said loading resulting in intimate and mechanically robust apposition between the composite interface and living tissue. It should be noted that such a method prevents excessive micromotion or strain at the interface between the implant (and/or the composite interface) and living tissue during the postoperative healing process, which, in essence, gives the bone a chance to further stabilize its fixation to the implant by way of bone modeling or remodeling in response to load transfer. Specifically, it is highly beneficial to maintain the strain state within living bone at and/or in the general vicinity of the bone implant interface within a range of 50 microstrain to 4000 microstrain so as to elicit the formation of bone tissue at and around the interface—strain levels in excess of 4000 microstrain or less than 50 microstrain are very likely to elicit the formation of fibrocartilagenous tissues at the interface which may lead to aseptic loosening of the implant. In the embodiment where the bone cement is injected, a small hole located at or beneath the skim cut allows for the injection of the material beneath the implant to achieve intimate and controlled interdigitation. [0043] Alternatively, the implant could be seated ‘over’ the freshly cut concave surfaces, and a slurry of biologically active and/or mechanically robust material(s) injected into the gaps between the implant and the bone under controlled pressure. Injection could be achieved via the portal shown in FIG. 34 . Such a slurry may comprise a mixture of substances such as morselized patient bone and bone cement, but alternative or additional materials including bone substitutes, osteobiologicals such as bone morphogenic proteins, antibiotics, or even living cells such as T cells known to promote post-operative healing and long term implant fixation. Beneficially, a fin feature may be added to these embodiments to facilitate additional mechanical stability, and said stem feature could beneficially possess an aperture for cross-pin fixation as described below for use in conjunction with the cross pins represented in FIG. 111 . [0044] Importantly, it is an objective of the embodiments of the present invention to preserve living, structurally viable bone tissue to facilitate the efficacy of any subsequent revision procedures. Further, the location and geometry of the concave tibial cut allows for the use of a bearing insert (conventionally made of materials such as polyethylene or other materials capable of ‘whetting’ or mimicking the benefits of ‘whetting’ during bearing contact; mimicking constituting, in one embodiment, the absence or mitigation of wear debris generation despite the application of significant bearing forces, in TKA in excess of 200 lbs and often as much as 500 lbs or more) whose ‘underside’ is convexly shaped to mate with a concavely shaped mating or accommodating surface in the upper surface of the tibial implant or ‘baseplate’ as it is sometimes referred to. This allows for a tibial insert(s) whose thickness, in the areas beneath where the femoral implant bears against the tibial insert, may be equal to or greater than those insert thicknesses used in the past (those associated with predominantly planar tibial cuts) while require removal of significantly less structurally viable bone from the cortical rim of the proximal tibia than past efforts. Determination of the geometry and location of the baseplate's concave surface and therefore the areas of greatest insert or bearing surface are easily determined by analysis of the wear patterns of retrieved tibial inserts. These embodiments of the present inventions also facilitate significant clinical benefits when applied to meniscal or rotating platform TKA designs as a high degree of conformity may be achieved while constraint is mitigated while preserving significantly more bone than prior art devices. Further, the reproducibility of the methods and apparatus described herein enable independent attachment of single compartment implants to bone to achieve Unicondylar, Bicondylar, Bicondylar and Patellofemoral, or Unicompartmental and Patellofemoral replacement of damaged bone surfaces while achieving the objectives of bone preservation, robust immediate and short and long term fixation, reproducibility of implant fixation and resulting location and orientation, and intraoperative ease of use. [0045] It should be noted that the cutting profile of the cutting tool shown in FIG. 29 may be curved in manner beneficial to endplate preparation in intervertebral fusion, dynamic disc replacement, and/or nucleus replacement as the cutting profile closely approximately the natural geometry of the endplates and provides for intimate fit with such prostheses fixation surfaces. In adapting this embodiment to tibial resection in either partial or complete knee replacement, the cutting profile of the tool would be shaped as desired to create the aforementioned cut surfaces in either one continuous movement of a single cutting tool, or incremental use of one or more cutting tools to cut bone to the desired shape and in the appropriate location and orientation, in all degrees of freedom, with respect to the tibia and/or femur and/or patella and/or soft tissues of the knee joint. [0046] Critically, in many applications of the tibial resection embodiments and methods described herein it is desirable that the Superior-Inferior thickness or diameter of the cutting tools used be less than the thickness of the bone to be removed in the creation of the cut surfaces so that the cutting surfaces of the cutting tool not contact soft tissue surface and bone surfaces located above the bone being removed. Alternatively, the cutting tool could be of such a thickness or diameter as to allow for the resection of both the femur and the tibia, or any such contiguous bones, to be prepared simultaneously with the passage of the cutting surfaces of a single tool across or along cut surfaces being created on both bones. Maintaining the desired geometric relationships between the contiguous or adjacent bone ends would be key in this embodiment of the present invention and could easily be obtained and maintained by use of a bracket fixed to the bones to establish and maintain the geometric relationship between said bones (see FIG. 30 for one embodiment of such a bracket employed to establish and maintain alignment between adjacent vertebral bodies. [0000] FIGS. 35 through 40 [0047] FIGS. 35 through 40 show embodiments of the present invention for femoral resection. For the sake of clarity, it should be noted that any combination of the forms of the present invention disclosed herein may be modified or combined to form constructs not specifically disclosed herein, but still within the scope of the present invention. The embodiments represented in FIGS. 29 and 30 are outstanding examples of this, as one of ordinary skill in the art would clearly recognize the applicability and benefits of this embodiment for tibial and/or femoral resection in Unicondylar or Bicondylar procedures, for bone resection in ankle replacement or arthrodesis (fusion), mandibular advancement procedures, high tibial osteotomy procedures, proximal femoral and acetabular preparation in Hip Arthroplasty, and many other applications where reproducible and safe removal of living tissue during surgical intervention is beneficial. [0048] FIGS. 35-40 shows an embodiment of the present invention wherein the guide plates and guide surfaces are located entirely outside the wound, but the side cutting drill and handle construct are not passed through mediolateral soft tissue portals described hereinabove. The side cutting drill controlling portion of the handle is essentially ‘snaked’ into the less invasive wound/exposure/approach/incision and the guide engagement features are engaged to the cutting guide at a location entirely outside the wound. As long as the axis of the engagement feature is maintained as coaxial with the side cutting drill, the desired cut geometries will be attained despite manipulation of the handle with respect to the guide. This method can be utilized to complete some or all of the desired cuts. Also, this embodiment of the current invention can be used to perform the posterior cut, posterior chamfer cut, and distal cut optionally using kinematic resection to reduce exposure requirements, and then removed from the wound and guide, flipped over 180 degrees from the orientation shown in FIG. 39 , reinserted into the wound and into engagement with the guide to cut the anterior chamfer cut and anterior cut with or without implementation of a kinematic resection technique and, optionally, with the knee in 15 degrees to 45 degrees to facilitate the soft tissue laxity and ease of use previously described. It should be noted that the mechanism for driving the side cutting drill is not represented in these figures and that a number of different options may be used. One way to accomplish drive input is generically represented in FIG. 40 , where a flexible drive shaft or bevel gear arrangement may be utilized to drive the side cutting form drill shown. Alternatively, chain, belt, or pneumatic drive mechanisms may also be used. FIG. 40 also represents an embodiment of the present invention which allows for the accurate and precise preparation of curvilinear cut surfaces, beneficially used in conjunction with guides containing curvilinear guide surfaces as represented in FIGS. 61 and 62 , to create cut surfaces for intimate attachment and fixation to implants represented in FIGS. 125, 126 , and/or 127 . [0049] FIGS. 93 through 98 represent an implementation of the side cutting drill embodiment of the present invention for cutting tools. It is of interest to note that the milling handle shown could further be guided by the PBR guides of the present invention to further combine the accuracy and precision benefits of PBR with the soft tissue protection characteristics of tibially embedded femoral cutting tool. It should also be noted that the side cutting drill with a curved cutting profile, similar to that shown in FIG. 119 , could also be used to attain cut geometries possessing simultaneously curved or curvilinear cutting profiles and cutting paths. In utilizing such, it would be critical that the side to side location of the cutting profile of the cutting tool be tightly controlled with respect to the desired side to side location of the implant as the side to side location of the implant would be dictated by the cut surfaces generated. Alternatively, a cutting tool with a linear cutting profile, as shown in FIG. 94 , could be utilized to create cut surfaces with a linear cutting profile and a curved cutting path, and then a second cutter with a curved cutting profile could be used to create a second, contiguous or noncontiguous, cut with a curved cutting profile and/or path whose mediolateral location was closely controlled to result in proper fit and location of the prosthesis attached to said cut surfaces. It should be noted that the cutting path of the second cutter could be located within a single plane, such as for a bilateral femoral component design, or could be curvilinearly divergent from the plane containing the cutting path of the first cut surface. This would be useful for unilateral femoral component designs (ones which require separate left and right femoral implants) so as to allow for the implant design to reflect out of plane patellofemoral kinematics and/or out of plane tibiofemoral kinematics most accurately. [0050] Interestingly, this embodiment of kinematic resection style resection could be modified to allow the cutting tool to be directly or indirectly linked to the movement of the patella with respect to the femur, or directly connected to the patella, to enable cutting of patellofemoral articular surfaces on the femur while moving the tibia and patella through ranges of motion about the tibia. The embodiments of cutting tools for use in attaining this include curvilinear end cutting mills or face cutters, side cutting drills with linear or non-linear cutting profiles, and other cutting tools capable of cutting the femur while engaged, directly or indirectly, to the patella. The side-to-side location of such cutters could be determined by engagement or adjustment with respect to a PBR or other guide, or simply by the natural kinematic path of the patella about the femur during flexion-extension of the knee joint. [0051] The complete disclosures of the patents, patent applications and publications cited herein are incorporated by reference in their entirety as if each were individually incorporated. Various modifications and alterations to this invention will become apparent to those skilled in the art without departing from the scope and spirit of this invention. It should be understood that this invention is not intended to be unduly limited by the illustrative embodiments and examples set forth herein and that such examples and embodiments are presented by way of example only with the scope of the invention intended to be limited only by the claims set forth herein.

Milling and drilling tools and soft tissue management techniques are provided for arthroplasty that facilitate intraoperative and postoperative efficacy and ease of use. In one embodiment, resiliently biased soft tissue protective sleeves surround a side cutting tool and are interposed along the longitudinal axis of the cutting tool, preferably adjacent each side of the bone. The soft tissue protective sleeves are biased to track along the contour of the side of the bone and prevent the cutting tool from being exposed to soft tissue during the resection. In another embodiment, a pilot drill is initially utilized to create an initial bore in the bone to be resected. The pilot drill preferably has an end cutting arrangement and a non-cutting removal channel that minimizes the tendency of the pilot drill bit to drift off-axis as the initial bore in the bone is created. Once the initial bore is created, the pilot drill bit is withdrawn and a second side cutting tool, such as a milling bit, is then inserted into the bore to perform the desired surface resection.

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] This invention relates to a material on hand checking method in inventory, and particularly a method that is capable of checking material shortage status of trial-run prototypes/modules applied to an inventory management system in the manufacturing industry. [0003] 2. Related Art [0004] To most enterprises and product manufacturers, there are many ways to increase profit margins, and managing costs is one of the ways. Moreover, management of material costs among cost categories is a matter of interest to enterprises. To satisfy required product quantities by customers or end users, those enterprises and product manufacturers have to prepare sufficient materials maintaining normal processes of productions. In default of maintaining sufficient stock inventory would suspend operations of production lines, so that finished goods from productions can not be delivered on time. This may lose potential commercial opportunities, cause the imbalance between supply and demand (disequilibrium), or reduce, even lose, market shares to those enterprises and product manufacturers. On the contrary, overstocks would cause a hoard of cash funds, difficulties in circulating capital and increase in management of costs, and the loss of margin profits from invisible risks of changeable product markets to those enterprises and product manufacturers. [0005] Daily faced problems to the manufacturing industry include: what parts or components need to be purchased, how to plan production schedules after purchasing material items, how to arrange delivery of finished goods from productions, how to manage excess/surplus stock, etc. For example, capacity forecast and formal orders are not the same thing, even a formal order would possibly change without any previous notice. Therefore, it is often to cause loss due to a stock-out or excess/surplus stock resulting from mistaken list making and incorrect materials preparation. However, current Material Requirement Planning (MRP) still has the following drawbacks: actual build orders (production orders) and build orders (production orders) for trial-run prototypes/modules are simultaneously sent to the system. Nevertheless, the system can not distinguish actual build orders from trial-run build orders. Where there is any material shortage, there is a superfluity of material purchase to increase inventory, instead of notifying purchase staff of making certain material purchase. As there is no much need of demands and production orders for most trial-run prototypes/modules, the Material Requirement Planning (MRP) system is unlikely to forecast quantities of required materials, but depends on rule of thumb of stock clerks to estimate quantities of required materials and bills of material (BOM). The Material Requirement Planning (MRP) system then issues required materials from inventory center/stock house according to an estimated sum. This kind of method takes too much cost of time and labor. [0006] Hence, material on hand checking method of trial-run prototypes/modules in the manufacturing industry has become a heavily focused subject. SUMMARY OF THE INVENTION [0007] In view of the foregoing, the invention aims at resolving the preceding disadvantages to provide a material on hand checking method of trial-run prototypes/modules. The primary object of the invention is to aim at proceeding quantity forecasts of required materials for trial-run prototypes/modules through the Enterprise Resource Planning (ERP) server of the enterprise end to manage inventory in the facilities. If there is any shortage, the Enterprise Resource Planning (ERP) server would make a marker and store it back to the storage media. Moreover, the Enterprise Resource Planning (ERP) server notifies managers that material on hand is only required for trial-run prototypes/modules. This further achieves the goal of heightening profits of enterprises by decreasing the risk of material purchasing and reducing a hoard of inventory. [0008] The disclosed material on hand checking method of trial-run prototypes/modules according to this invention at least consists of: receiving at least one build order through the Enterprise Resource Planning (ERP) server, determining if the build order is for a trial-run prototype/module through the Enterprise Resource Planning (ERP) server, transferring the build order back to a storage media according to the Enterprise Resource Planning (ERP), exploding bill of material (BOM) of the build order through the Enterprise Resource Planning (ERP) server, and integrating the bill of material (BOM) and storing it back to a storage media through the Enterprise Resource Planning (ERP). [0009] The foregoing, as well as additional objects, features and advantages of this invention will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings. Specific structures and functional details disclosed hereunder are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention. BRIEF DESCRIPTION OF THE DRAWINGS [0010] [0010]FIG. 1 is a schematic representation of material on hand checking method of trial-run prototypes/modules of this invention. [0011] [0011]FIG. 2- a is a flowcharted representation of material on hand checking method of trial-run prototypes/modules according to this invention. [0012] [0012]FIG. 2- b is a sub-flowcharted representation of exploding bills of material (BOM) according to this invention. [0013] [0013]FIG. 3 is presently known exploded view of bills of material (BOM) of the information system. [0014] [0014]FIG. 4 is an exploded view of bills of material (BOM) according to this invention. DETAILED DESCRIPTION OF THE INVENTION [0015] This invention proposes a material on hand checking method of trial-run prototypes/modules. In particular, the method, based on the advocacy of the up-to-date Business Process Re-Engineer (BPR), mainly aims at improving effective utilization and management of enterprise resources and re-engineering working processes of managing and checking material quantities of trial-run prototypes/modules. This is to decrease the risk of overstock and to reduce operation costs of the organization. [0016] Prior to this invention, the introduction of production process of a notebook computer for showing the importance of trial-run prototypes/modules is described hereunder. [0017] The production process of a whole new notebook computer (laptop) generally comprises two phases, one is research and development (R&D) and trial-production (trial-run) phase, and the other is quantity-production phase in the factories. This production process pattern is almost applied to all electronic products. The details are as follows. [0018] A. R&D and trial-production (trial-run) phase: [0019] 1. Market information collection: both R&D and marketing departments collect market information to analyze the feasibility of a new product and to decide specifications of that product. [0020] 2. Prototype/module design: product specifications, such as PCB (printed circuit board) design, parts and components, materials, and outlook, are delivered to designers of relevant departments for detailed design. [0021] 3. Prototype/module testing: sections of original prototype/module design are tested for defects and instant rectification. [0022] 4. New production lines for trial-run prototype/module: that modified prototype/module would be delivered to facility to create sections of the prototype/module and to factories/manufactories for productions. All improper design, especially the PCB part, would be re-rectified during the process of trial-production. Also, there are various testing for the new product to be forthwith rectified to heighten feasibility for productions on trial-production phase. However, the system is unable to estimate quantities of parts and components and provide materials with accuracy, even if the trial-run prototype/module had passed all kinds of testing and whole production process had been determined. The reason is that some of parts and components on the bill of material (BOM) of a trial-run prototype/module are, as often as not, duplicate with that of other different prototypes/modules. Besides, the trial-run prototype/module only needs quite small quantities of required materials. Therefore, either there is no material being issued by the system, or overstock from purchasing makes a hoard of inventory. [0023] B. Quantity productions phase in the factories/manufactories: [0024] Once a trial-run prototype/module passed the trial-production phase without any problems in production process and product usage, the trial-run prototype/module would be able to be distributed to production lines in the factories/manufactories for quantity-productions. [0025] The aforementioned indicates the importance of the process of trial-productions in the manufactory industry. [0026] The feasibility and practicality of this invention will be elaborated by means of an embodiment depicted in the following. With reference to FIG. 1, the schematic representation of material on hand checking of trial-run prototypes/modules of this invention illustrates details as follows. [0027] First, after determining a trial-run prototypes/modules, the Enterprise Resource Planning (ERP) server 100 of the enterprise end integrates and manages all material resources in the enterprise end, captures stock data from a storage media 110 . There are various material stocks and finished goods in different facilities 50 a˜n, among which all stocks can be analyzed and contrasted with quantities of required materials between the stock house/inventory center and the trial-run prototype/module by the Enterprise Resource Planning (ERP) server 100 . As there is actual demand and production order for the trial-run prototype/module, such a build order 10 , therefore, can be directly placed into the Enterprise Resource Planning (ERP) server 100 for calculation. This is different from conventional known trial-run prototypes/modules of no demands and production orders. According to the build order 10 , the Enterprise Resource Planning (ERP) server 100 can explode the bill of material (BOM) 80 of the trial-run prototype/module before calling inventory status on the storage media 110 for item-by-item contrast. The Enterprise Resource Planning (ERP) server 100 then finds part numbers of stock-outs through a searching method to make a marker for decision-makers references. [0028] With reference to FIG. 2- a, the flowcharted representation of material on hand checking method of trial-run prototypes/modules according to this invention represents the detail hereunder. [0029] First, the Enterprise Resource Planning (ERP) server 100 receives at least one build order (step 200 ), and the information of a trial-run prototype/module comprises at least: the facility 50 and required quantity of the trial-run prototype/module. After receiving the build order, the Enterprise Resource Planning (ERP) server 100 determines if the build order 10 is for a trial-run prototype/module (step 210 ). If the build order 10 is not for a trial-run prototype/module, the facility 50 implements the build order 10 (step 215 ). If so, the Enterprise Resource Planning (ERP) server 100 transfers the information of the build order 10 back to a storage media 110 (step 220 ), which provides a plurality of columns to store different contents. The Enterprise Resource Planning (ERP) server 100 then explodes the bill of material (BOM) of the build order (step 230 ). When the bill of material (BOM) is completely exploded, the Enterprise Resource Planning (ERP) server 100 integrates the bill of material (BOM) and stores it back to the storage media 110 (step 240 ) and terminates the function flow of the material on hand checking method. The way for the Enterprise Resource Planning (ERP) server 100 to integrate the bill of material (BOM) 80 is to calculate quantity of available stock for the trial-run prototype/module from the quantity difference of inventory stock and reserved stock. The way for the bill of material (BOM) 80 stored back to the storage media 110 is to store part numbers and quantities of stock-outs for trial-run prototype/module into the columns provided by the storage media 110 for decision making purposes. [0030] The aforementioned exploding bill of material (BOM) method of the trial-run prototype/module refers to FIG. 2- b, the sub-flowcharted representation of exploding bills of material (BOM) according to this invention. [0031] First, the method is to explode all bills of material (BOM) of trial-run prototypes/modules (step 231 ), then combine components or parts at the first level of bill of material (BOM) (step 232 ). When the first level of bill of material (BOM) is completely combined, then the method explodes components or parts at the first level of bills of material (BOM) (step 233 ). When the first level of bill of material (BOM) is completely exploded, the method then combines components or parts at the second level of bill of material (BOM) (step 234 ). When the second level of bill of material (BOM) is combined, the method then explodes components or parts at the second level of bill of material (BOM) (step 235 ). Repeating the above process of combining and exploding the bill of material (BOM) until the last level of bill of material (BOM) is completely drilled down (step 236 ). [0032] The above mentioned bill of material (BOM) 80 can be a product tree of an enterprise and further comprises at least one common material and at least one specific material. The meanings of specific materials and common materials are: the specific materials are specified components or parts needed for respective prototypes/modules, no components and parts among which are overlapped in common; the common materials relate to general components or parts needed for all prototypes/modules, and are evaluated by pre-set columns through the Enterprise Resource Planning (ERP) server. [0033] [0033]FIG. 3 is a presently known exploded view of bills of material (BOM) that illustrates the exploding method of bill of material (BOM) as follows, [0034] First, the system explodes the first level of bill of material (BOM) of prototype A (material modules C, D, and E), then explodes the second level of bill of material (BOM) (material modules H, I, I, J, and K). At the second level of bill of material (BOM) there is a material module I being repeatedly exploded, as material module I belongs to parent material module C, as well as parent material module E. Finally, the system drills down to the third level of bill of material (BOM) (material modules L, M, N, and O). At the third level of bill of material (BOM) there are material modules L and M being repeatedly exploded. As both L and M belong to parent material module I, which is one of sub-components to its parent material modules C and E, thus module I is repeatedly exploded. [0035] After prototype A is exploded, the system then begins to explode the first level of material (BOM) of prototype B (material modules C, F, and G), then explodes the second level of bill of material (BOM) (material modules H, I, I, and J). At the second level of bill of material (BOM) there is a material module I being repeatedly exploded, as material module I belongs to parent material module C, and also belongs to parent material module F. Finally, the system drills down the third level of bill of material (BOM) (material modules L, M, L, M, and P). At the third level of bill of material (BOM) there are material modules L and M being repeatedly exploded, as both L and M belong to parent material module I, which is one of sub-components to its parent material modules C and F. The exploding process, therefore, is completed. [0036] [0036]FIG. 4 is an exploded view of bills of material (BOM) according to the disclosed invention that illustrates the exploding method of bill of material (BOM) as follows. [0037] The exploded method of this invention: first, the system explodes all bills of material (BOM) of respective prototypes (prototype A and B, for example), combines the first level of bills of material (BOM) of both prototypes A and B, and then explodes the first level of bills of material (BOM) (material modules C, D, E, F, and G), followed the first level of bill of material (BOM) of both prototypes A and B being completely combined. When the first level of bills of material (BOM) of both prototypes A and B are exploded, the system drills down to the second level of bill of material (BOM) to combine bills of material (BOM) of both prototypes A and B. The system then explodes the second level of bill of material (BOM) (material modules H, I, J, and K), followed the second level of bills of material (BOM) being completely combined. When the second level bills of material (BOM) of both prototypes A and B are exploded, the system drills down to the third level to combine bills of material (BOM) of both prototypes A and B. The system then explodes the third level of bill of material (BOM) of both prototypes A and B (material modules L, M, N, O, and P). The exploding process is, therefore, completed. [0038] Hence, the exploded method of bill of material (BOM) consists of the following steps: first, exploding all bills of material (BOM) of respective prototypes, then stratifying all levels of bills of material (BOM), according to assemble features of respective prototypes. Finally Combining and exploding components or parts at each level of all integrated bills of material (BOM). [0039] This exploded method can largely reduce the burden to the system resources, enhance efficiency, and enable material management and distribution more effective. [0040] In sum, conventionally known method of exploding bills of material (BOM) has to repeatedly explode material items to match the tree structure of bills of material (BOM). Take material module M as an example that it has been exploded for four times, and it heavily occupies the hardware space and wastes the time for exploding. Therefore, this disclosed invention utilizes combination method to explode bills of material (BOM) for the following advantages that, [0041] 1) Each material is exploded only once to save time in exploding bills of material (BOM); [0042] 2) Common materials of respective prototypes are easy to be understood; [0043] 3) It saves resources of information system; [0044] 4) It shorten time for searching material modules (prototypes only need to be exploded once, no necessary to search various prototypes one-by-one); [0045] 5) It is no necessary to have duplicated storage so as to save memory space. [0046] The invention in the form of the no demand trial run module material on hand checking method is disclosed herein. These and other variations, which will be understood by those skilled in the art, are intended to be within the scope of the invention as claimed below. As previously stated, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various forms.

A material on hand checking method of trial-run prototypes/modules aims at resolving the problem of not able to forecast material shortage of trial-run prototypes/modules in electronic format by enterprises. Through the calculation method, when there is a request of trial-producing (trial-running), the Enterprise Resource Planning (ERP) server is capable of controlling and managing the inventory system, estimating required materials of trial-run prototype/module based on certain steps and procedures, and opening a new trial-run production line for productions. Enterprises can, therefore, decrease overstock in the facilities, reduce the risk of material purchasing and increase profit margins.

RELATED APPLICATIONS [0001] This application claims priority from the commonly-assigned U.S. provisional patent application Serial No. 60/637,659, filed on Dec. 21, 2004, the contents of which are incorporated here by reference. [0002] This application is also related to the following co-pending commonly-assigned patent application Ser. No. 10/293,943 of Sloate et al. entitled, “MULTIPLEXED SECURE VIDEO GAME PLAY DISTRIBUTION.” TECHNICAL FIELD [0003] The technology described relates to testing prototype software, and more particularly, to secure electronic delivery and evaluation of prototype software distributed over a network to third parties. One non-limiting example application is to testing and evaluating prototype game software. BACKGROUND [0004] Traditionally, software is used on “local” hardware. Consider video game software. A video game is typically purchased for use with a home video game system such as the Nintendo GameCube system or a home personal computer (PC). Home is a general term used as a contrast to playing a game at an arcade. To play a game, the user usually selects a video game on optical disk or other storage device and then controls the “local” hardware to begin executing the game. The game is then displayed on the user's television set, personal computer display, or a handheld computer display. But there are instances where software needs to be used on “remote” hardware. One such instance may occur during the software development. [0005] Before software is provided in its final form to end-users, it goes through a development, testing, and evaluation process. As the software moves through various stages of the process, it is oftentimes desirable to send that software to parties other than the developers to execute and experience (hereafter “third parties”). Those third parties, which may be part of the software development organization or outside of it, then test and/or evaluate the software. They often make suggestions to the software developers and/or marketers to help improve the software's performance and/or appeal. Although it is possible to bring such third parties to the physical plant of the software developer and carefully control the conditions under which third parties evaluate the prototype software, it may be more convenient and efficient to have third parties test prototype software away from the developer's physical plant. [0006] But testing outside the developer's physical plant raises security issues regarding the software. Most important is how to prevent illegal copying when the software is distributed electronically, when it is being tested, and when testing is complete. One security approach is to load the prototype software into a secure “lock box,” and have a developer employee physically deliver the prototype software to the third party evaluator. The delivery person must monitor its use, and when the third party evaluator is done, make sure that no copies were made and that the lock box copy is securely returned to the software developer. The time and expense associated with this approach are significant. Moreover, there is always a risk that the prototype software may be lost, stolen, or otherwise misappropriated despite precautions and preventive efforts. SUMMARY [0007] The technology described below overcomes these problems. The technology securely delivers software over a network to an evaluation site and monitors the evaluation of the software at the delivered site also via the network. In one example application, the software is prototype software to be tested by a third party different from a developer of the prototype software. One example prototype software is game software. The software is encrypted using one or more levels of encryption (preferably at least two). The encrypted software is transmitted from a server over the network to a client at the evaluation site for execution of the software to permit the evaluation of the software. But before the software can be executed, the client is initially authenticated by the server over the network. If the authentication is positive, the server authorizes execution of the software at the client. The server monitors the evaluation during the execution of the software at the client and determines whether the evaluation should be halted. The monitoring by the server prevents unauthorized use of the prototype software at the client. [0008] If the evaluation is halted, the server prohibits execution of the software or access to the software at the client. For example, the server may, via its control of the software at the client via the network, erase the prototype software from the client machine. The server may also prevent transmission, copying, or modification of the software at the client. [0009] The server may halt the evaluation for other reasons. For example, the client may be given only a certain time period or window during which the evaluation may be conducted. The server starts a check out period associated with when the server transmitted the software over the network to the client, monitors the check out period, and prohibits further execution of the software or access to the software at the client when the check out period expires. [0010] The monitoring may include the server periodically prompting the client to provide the server with some information, If the client fails to provide the prompted information within a predetermined time period, then the server prohibits execution of the software or access to the software at the client. The initial authentication may include requiring the client to provide the server a correct log-in identifier and a correct password. [0011] The client electronically receives the software via the network. Assuming the software is encrypted on at least two encryption levels, the client decrypts the software at one of the encryption levels and stores the decrypted software. The client initially performs authentication over the network with the server. For example, the client may have to provide the server with a correct log-in identifier and a correct password. If the authentication is positive, the software is temporarily stored at the client machine. Preferably, the software is temporarily stored in a password-protected hard disk drive that renders contents stored on the hard disk drive inaccessible to the evaluator. If the authentication is positive, the client is also permitted to decrypt a first portion of the software at the other of the encryption levels and executes the first software portion to permit evaluation of the first software portion. After decrypting the first portion and before execution of the first software portion is completed, the client decrypts a second portion of the software at the other of the encryption levels and executing of the second software portion to permit evaluation of the first software portion. This on-the-fly decryption of the software to be next executed is advantageous both in terms of security and in terms of efficient software execution. [0012] During the decrypting and executing, the client receives over the network multiple prompts from the server. The client responds to the prompts to ensure continued execution and evaluation of the software at the client. Access to and execution of the software is controlled by the server. Control signals from the server over the network prevent unauthorized use of the prototype software at or by the evaluator including preventing transmission, copying, or modification of the prototype software. BRIEF DESCRIPTION OF THE FIGURES [0013] FIG. 1 is function block diagram illustrating one non-limiting example of a system for securely delivering and monitoring evaluation of prototype software over a network; [0014] FIG. 2 is a flowchart illustrating non-limiting example procedures for securely delivering and monitoring evaluation of prototype software over a network; [0015] FIG. 3 is function block diagram illustrating another non-limiting example of a system for securely delivering and monitoring evaluation of prototype software over a network; and [0016] FIG. 4 is function block diagram illustrating another non-limiting example of a system for securely delivering and monitoring evaluation of prototype game software over a network. DETAILED DESCRIPTION [0017] In the following description, for purposes of explanation and non-limitation, specific details are set forth, such as particular nodes, functional entities, techniques, protocols, standards, etc. in order to provide an understanding of the described technology. It will be apparent to one skilled in the art that other embodiments may be practiced apart from the specific details disclosed below. In other instances, detailed descriptions of well-known methods, devices, techniques, etc. are omitted so as not to obscure the description with unnecessary detail. Individual function blocks are shown in the figures. Those skilled in the art will appreciate that the functions of those blocks may be implemented using individual hardware circuits, using software programs and data in conjunction with a suitably programmed microprocessor or general purpose computer, using applications specific integrated circuitry (ASIC), field programmable gate arrays, one or more digital signal processors (DSPs), etc. [0018] Reference is now made to FIG. 1 which illustrates an example software (SW) evaluation system 10 which includes a software (SW) developer facility or location 12 coupled to a software (SW) evaluator facility or location 16 via a network 14 (or some other electronic communications medium). The software developer facility 12 and the software evaluator facility 16 may or may not be within the control of the software developer. In other words, the software client 20 may be an in-house evaluator and the network 14 may be a private local area network (LAN). The term client includes a machine, a software entity or program, etc. On the other hand, the software evaluator might not be under the control of the software developer 12 . In that case, the network 14 might be a public communications network such as the Internet. [0019] The software developer facility 12 includes a software server computer 18 that includes a data processor 22 , a memory 24 , a display 26 , and a user interface 28 . The memory 24 stores prototype software 30 to be evaluated and a server application 31 for remote testing of prototype software including an encryption routine 32 , an authentication routine 34 , and a monitoring routine 36 . [0020] The encryption routine may include one or more proprietary and/or publicly known encryption algorithms. In a preferred example embodiment, the prototype software 30 is distributed over the network in a multi-level encrypted format. For example, the software 30 may be encrypted with a first encryption layer and a second encryption layer. The second encryption layer is used for added protection while the software is electronically distributed over the network 14 . Each encryption layer preferably uses different encryption algorithms, although the same encryption algorithm could be used but with different parameters at each layer, e.g., different encryption keys, passwords, etc. [0021] Once the prototype software has been successfully transferred to the remote software facility 16 , the second encryption layer may be removed by the software client 20 leaving the first encryption to protect the software program during storage at the client. Multiple encryption layers ensures a very high level of security for the prototype software when it is most likely to be intercepted by an unauthorized party during network transmission. Once physically temporarily stored at the third party station, the prototype software is less prone to rogue attack. Removing one or more extra encryption layers before storage permits faster execution of that prototype software at the third party client. By removing one encryption layer before storage, the prototype software can be executed more quickly, and as a result, tested more efficiently. The second encryption level could be, for example, public-private key cryptography with the SW server and client processors being provided with the necessary keys. Consequently, the software remains encrypted even after arrival and temporary storage at the client 20 to protect it against attack while stored at the client 20 . Greater security may be provided by adding further encryption levels, if desired. [0022] The authentication routine 34 authenticates a software client user (the software evaluator) and performs log-in identification, password verification, and then an on-going authentication dialog between the software server 18 and the software client 20 . The initial authentication must be successfully completed in order for the software to be temporarily stored by or at the client machine. If that authentication dialog is broken prematurely or is not conducted in accordance with the authentication protocol, the monitoring routine 36 in the server application 31 prevents the client application 52 from executing the prototype software. To resume execution, the user must perform some type of re-authorization process, e.g., repeat the log-in authentication procedure. [0023] The software client 20 includes a processor 40 , display 42 , a user interface 44 , and a memory 46 for storing the electronically-transferred prototype software 30 , preferably in encrypted format at 48 . In a preferred example embodiment, the processor 40 employs a decryption routine 50 to remove a top level of encryption before storing the software 38 in the memory 46 . The client application 52 includes an authentication routine 54 for communicating using the required protocol with the server's authentication routine 34 . The client application 52 also includes a remote access control routine 56 which gives the server application 31 remote control over the client 20 for the testing process until the client 20 no longer can access the prototype software. This control ensures only authorized users test the prototype software and only authorized use is made of the prototype software. The remote control prevents unauthorized use such as copying, modifying, or electronically distributing prototype software. [0024] Once the software client 20 has properly logged on and been authenticated by the server application 31 , the server application 31 enables the client processor 40 , via the remote access routine 56 , to access the prototype software 48 stored in the memory 46 . Assuming the prototype software 48 is stored in decrypted form, the client is provided by the processor 40 with the appropriate decryption tools to decrypt the prototype software for execution on-the-fly. On-the-fly decryption is preferred because it provides an extra level of security where only the specific software needed for immediate execution is available, while the remainder of the prototype software remains encrypted. On-the-fly decryption is also advantageous because the tester does not need to wait for the longer time that it takes for the entire prototype software to be decrypted. Alternatively, a hardware board or other device may be provided to the SW evaluator 16 and coupled to the client machine so as to perform the decryption. The SW evaluator 16 then is free to execute the prototype software for testing and evaluation. [0025] The security monitoring routine 36 at the SW developer facility 12 establishes a testing time period during which the SW client 20 is authorized to evaluate the prototype software. Once that time has expired, the security monitoring routine 36 halts further execution of the prototype software at the SW client 20 and erases that software from the memory 46 via the remote access control routine. The security monitoring routine 36 may perform other operations like searching the client memory 46 for unauthorized files and either erasing them or notifying the software developer. [0026] Reference is now made to the flow chart diagram in FIG. 2 illustrating example procedures for carrying out a method in accordance with one illustrative embodiment. Initially, an authorized person at the software developer facility 12 identifies prototype software to be tested along with the testing or evaluating entity, and obtains approval before distributing the prototype software for evaluation or other testing (step S 2 ). The prototype software, if not already encrypted, is encrypted using one or more layers of proprietary and/or public encryption algorithms (preferably multiple layers) (step S 4 ). The encrypted software is then sent electronically, e.g., over some sort of network, to a client where the encrypted software is stored in memory 48 . While the client could be run on a common personal computer (PC) or the like, the client may also be implemented using a special testing machine to increase security. After removing at least a first encryption layer in the preferred embodiment, the stored prototype software may, in some implementations such as those described later, be password protected to further prevent unauthorized copying. A “check-out” time period is started by the monitoring routine 36 (step S 6 ). The third party evaluator interacts with the software client 20 via the display and user interface to log-in with the software server via the network using, for example, a log-in ID and a log-in password (step S 8 ). The server application 18 authenticates the evaluator, and instructs the client processor 40 to decrypt on-the-fly the encrypted prototype software being retrieved from memory 48 and then execute the prototype software (step S 10 ). [0027] As the prototype software is executed on the software client, an authentication dialog is maintained between the server and the client. If that dialog is broken or is otherwise improper, the server disables the client from further execution of the prototype software (step S 12 ). Once the check out period expires, the server erases the prototype software from the client memory and disables any further execution of that prototype software at the client (step S 14 ). [0028] FIG. 3 illustrates another non-limiting example software evaluation system similar to that shown in FIG. 1 . But in this embodiment, the client works in conjunction with a software execution engine 54 that includes hardware and/or software 56 that is specifically configured to execute the prototype software. The software execution engine 54 also includes a memory 58 (such as a hard disk drive) to store the prototype software (preferably encrypted) received via the network 14 and the client 20 from the software server 18 . The software execution engine 54 may be integrated with the client machine 20 or may be coupled to the client machine 20 . Such an execution engine 54 may be necessary or useful for specialized or otherwise proprietary prototype software execution. Moreover, the software execution engine 54 permits additional security. For example, if memory 58 is a hard drive, it may be password protected using an advanced technology attachment (ATA)-based password. Such password protection is typically not readily implemented for the hard drive of the client 20 . [0029] In this example embodiment, the client 20 stores the client application 48 , which includes an authentication routine 50 , to perform log-on and then handshake communications with the server authentication routine 34 during the time when the prototype software is being executed by the software evaluator. In addition, the client application 48 includes a remote access control routine 52 that permits the monitoring routine 56 in the software server 18 to control the client machine 20 at least with respect to its handling of the prototype software. Once the test period expires or there has been some other event, the monitoring routine 36 erases the prototype software from the memory 58 via the remote access control routine 52 . [0030] FIG. 4 shows another example non-limiting embodiment applied to video games. A video game developer facility 60 includes a game server 68 coupled via the Internet 62 to a game evaluator facility or location 64 . Access to the Internet by the server 68 and the client 92 may be for example, by way of respective virtual private network (VPN) adaptor 90 . The game evaluator facility 64 is coupled via a USB link to a game execution engine 66 . The game server 68 includes a processor 70 , a display 72 , a user interface 74 , and a memory 76 . The memory 76 includes prototype game software 78 to be evaluated by the game evaluator. The memory 76 also includes a server application 80 with an encryption routine 81 , an authentication routine 82 , and a monitoring routine 88 . [0031] The client 92 includes a processor 94 , a client application 95 which includes an authentication routine 96 and a remote access control routine 97 , a display, a user interface, coupled to a game controller 102 . The game execution engine 66 includes game-specific execution hardware and/or software 104 . One non-limiting example of a specialized game execution engine might include hardware and software from a Nintendo GameCube entertainment system that readily supports play of prototype video games being designed for Nintendo's GameBoy Player. [0032] The hard disk drive (HDD) 106 stores the downloaded prototype software received from the client 92 in an encrypted format. The game-specific execution hardware and/or software 104 is able to decrypt the prototype game software on-the-fly during game play. As in FIG. 3 , the hard disk 106 is protected by a password based on ATA security which renders the hard drive inaccessible outside of the system shown in FIG. 4 . [0033] The above technology provides substantial advantages for testing and evaluating software. The software may be provided cheaply and securely by any suitable electronic means. There is no need for humans to deliver, monitor, and retrieve the software at remote test sites. Control of the software is maintained throughout the delivery, test, and evaluation process by the software developer. Various security features ensure that the software is not compromised or copied during any part of that process. [0034] Although various embodiments have been shown and described in detail, the claims are not limited to any particular embodiment or example. None of the above description should be read as implying that any particular element, step, range, or function is essential such that it must be included in the claims scope. The scope of patented subject matter is defined only by the claims. The extent of legal protection is defined by the words recited in the allowed claims and their equivalents. No claim is intended to invoke paragraph 6 of 35 U.S.C §112 unless the words “means for” are used.

Prototype software is securely delivered and evaluated by electronic transfer over a network. The software is secured by multiple levels of encryption to prevent unauthorized copying, modification, and/or use of the prototype software. Electronic transfer of the prototype software minimizes the time and cost associated with providing prototype software for testing to remote third party testers. Once the software has been transferred electronically to the third party tester, the software developer electronically maintains control of that software by restricting access to an authorized third party, monitoring testing, and deleting any files related to the prototype software from the third party test workstation.

RELATED APPLICATION This patent arises from an application claiming priority as a continuation of U.S. application Ser. No. 12/644,151, (Now U.S. Pat. No. 8,549,267), entitled “METHODS AND APPARATUS TO MANAGE PARTIAL-COMMIT CHECKPOINTS WITH FIXUP SUPPORT” which was filed on Dec. 22, 2009, granted on Oct. 1, 2013 and is hereby incorporated herein by reference in its entirety. TECHNICAL FIELD The present disclosure relates to speculative execution, and in particular, to methods and apparatus to manage partialcommit-checkpoints with fixup support. BACKGROUND In the context of microprocessors, a speculative execution system (SES) is a system that enables the speculative execution of instructions. Speculative execution is typically leveraged to enable safe execution of dynamically optimized code (e.g., execution of optimized regions of code in a hardware (HW) and/or software (SW) co-designed systems). The data produced by the speculative execution of instructions is typically referred to as speculative data. To ensure correct execution, the system may protect the current architectural state (e.g., the state visible by the user) by keeping it unmodified during the speculative execution of instructions. If the speculative execution is incorrect, the SES discards the speculative data and makes one or more attempts to re-execute the instructions again. In some circumstances, additional attempts to re-execute the instructions occur by way of a more conservative approach (e.g., via a non-speculative execution of instructions, via a smaller degree of speculation in the execution, etc.). On the other hand, in the event that the speculative execution is proven correct, the SES may convert the speculative execution into a non-speculative execution, thereby changing the architectural state. This may be done by promoting the speculative data to non-speculative data. BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1, 2 and 3 are block diagrams of example platforms that may be used by the methods and apparatus described herein to generate partial commit-checkpoints. FIGS. 4, 5, 6, 7 and 8 are example code blocks that may be executed in connection with the example platforms of FIGS. 1-3 . FIG. 9 is a block diagram of an example fixup code circuit that may be used by the example platforms of FIGS. 1-3 . FIGS. 10-12 are example processes that may be carried out using instructions stored on tangible machine readable media to implement the example fixup code circuit of FIGS. 1-3 and 9 . FIG. 13 is a schematic diagram of an example processor platform that may execute the example processes of FIGS. 10-12 and/or the example fixup code circuit of FIGS. 1-3 and 9 . DETAILED DESCRIPTION As described in further detail below, the methods and apparatus described herein may be implemented under the assumption that a processor that employs a speculative execution system (SES) may either perform speculative execution (S) of instructions (I), and/or non-speculative execution (N) of instructions (I). Additionally, the example SES may perform a Checkpoint (K) before any speculative execution (S) of instructions. The example Checkpoint ensures that the architectural state of the processor is protected from speculative execution until the SES performs a Commit (C). After the Checkpoint, the processor (e.g., a microprocessor) can speculatively execute any number of instructions. If the speculative execution of the instructions is proven correct, the SES may perform a Commit (C), which may modify the architectural state of the processor with the data computed by the speculative execution. If the speculative execution is incorrect, the SES may perform a Recovery (R) by discarding the speculative data and rolling the execution back to the last Checkpoint performed. After a Commit or a Recovery, the example SES may either start a non-speculative execution of instructions (N) or perform a new Checkpoint and continue speculatively executing other instructions (S). A speculative execution (S) of instructions is usually limited to instances between a Checkpoint (K) and a Commit (C) or, in some instances between a Checkpoint (K) and a Recovery (R). The dynamic region of code composed by all the instructions speculatively executed between a Checkpoint (K) and a Commit (C) and/or between a Checkpoint (K) and a Recovery (R) may be considered a dynamic atomic region. Additionally, Recovery and Commit operations may be either conditionally coded inside an atomic region (e.g., assert), or dynamically injected by HW when unexpected speculative results are detected (e.g., exception). As used herein, the term “atomic region” refers to instances in which all the speculative data is turned into non-speculative data by the Commit operation (C), and/or all the speculative data is discarded by the Recovery (R) operation. Dynamic execution of code by an example processor may occur in any number of execution sequences (E). In the illustrated examples of Equations 1 through 3, I refers to zero or more static instructions in a static program, K refers to a dynamic Checkpoint operation performed by an SES execution, C refers to a dynamic Commit operation performed by an SES execution, R refers to a dynamic Recovery operation performed by an SES execution, S refers to a speculative execution of zero or more static instructions (I), and N refers to a non-speculative execution of zero or more static instructions (I). E 1 = KSCKSCKSRNKSC . Equation ⁢ ⁢ 1 E 2 = KSC ︷ Atomic ⁢ ⁢ Execution ⁢ ⁢ N ︸ Non ⁢ - ⁢ Spec ⁢ ⁢ Execution ⁢ ⁢ KSR ︷ Atomic ⁢ ⁢ Execution ⁢ ⁢ KSC ︸ Atomic ⁢ ⁢ Execution . Equation ⁢ ⁢ 2 E 3 = KSC ︸ Atomic ⁢ ⁢ Execution ⁢ KSC ︷ Atomic ⁢ ⁢ Execution ⁢ KSR ︸ Atomic ⁢ ⁢ Execution ⁢ N ⁢ ⁢ KSC ︷ Atomic ⁢ ⁢ Execution ⁢ N ⁢ ⁢ KSC ︸ Atomic ⁢ ⁢ Execution . Equation ⁢ ⁢ 3 In some example SESs, execution is optimized by way of employing an operation that performs a Commit (C) and a Checkpoint (K) in a single operation, which may be referred-to as a “Commit-Checkpoint” (C k ). An example Commit-Checkpoint (C k ) may execute Commit (C) and then a Checkpoint (K) during execution of back-to-back atomic regions. Example Equation 4 below illustrates an example Commit-Checkpoint (C k ) derived from Equation 3 above. E 4 = KSC k ⁢ SC k ⁢ SR ⁢ ︷ Back ⁢ ⁢ to ⁢ ⁢ back ⁢ ⁢ atomic ⁢ ⁢ execution ⁢ ⁢ of ⁢ ⁢ 3 ⁢ ⁢ regions ⁢ N ⁢ ⁢ KSC ︸ Atomic ⁢ ⁢ Execution ⁢ N ⁢ ⁢ KSC ︷ Atomic ⁢ ⁢ Execution . Equation ⁢ ⁢ 4 The example Commit-Checkpoint (C k ) operations typically save a precise architectural state so that, in the event of a failure of a Speculative execution (S), the example SES may recover the state back to a point in which the Commit-Checkpoint (C k ) was performed. The point at which the Commit-Checkpoint (C k ) was performed is considered a safe state and allows regular execution to be reattempted. Any such reattempt at execution is typically performed in a more conservative manner, such as by way of non-speculative execution of instructions (N), as shown in example Equation 5 below. E 5 =K 1 S 1 C K2 S 2 C K3 S 3 C K4 S 4 R 4 N 4 K 5 S 5 C K6 S 6 C K7   Equation 5. In the illustrated example of Equation 5, execution five (E 5 ) includes a Commit-Checkpoint (C k4 ) that commits speculative results of S 3 and saves a precise architectural state. Thereafter, the example SES performs a Recovery operation (R 4 ) to recover a precise architectural state saved at C k4 . As described above, in response to one or more failures of speculative execution, some SESs proceed by executing code in a more conservative manner, such as the example Non-Speculative operation (N 4 ) shown above. In the event that a processor requires a precise architectural state when performing a Commit-Checkpoint operation, dead code and/or partially dead code may not be optimized across the atomic region(s). Generally speaking, partially dead instructions include those that produce a value that may not be used by subsequent computations. Instructions that define architectural values that are not used by code in subsequent atomic regions are partially dead because they still might be needed by exception and/or interruption handlers executed between one or more atomic region(s). For example, in the illustrated example of Equation 5, operations in S 3 that compute architectural values that are overwritten by operations in S 4 cannot be eliminated because C k4 requires a precise architectural state when saving the state. The state saved in the illustrated example must also include the state computed by S 3 and overwritten by S 4 . The methods and apparatus described herein allow, in part, replacing a Checkpoint (C ki ) by a partial commit-checkpoint P i (fu i ) operation that saves only a portion (e.g., a non-precise architectural state) of the architectural state of the processor. As such, one or more optimizations may be performed with one or more atomic regions when dead code and/or partially dead code are identified. The example partial commit-checkpoint P i (fu i ) is associated with fixup code fu i . In operation, if execution rolls back to the example partial commit-checkpoint P i (fu i ) and the processor requires a full (precise) architectural state, then the example SES executes the fixup code fu i to recover the full architectural state. Checkpoints are created prior to speculative execution so that the prior CPU state may be recovered in the event that a speculation was incorrect. Once the CPU state has been recovered, then execution may resume by executing a more conservative version of the code (e.g., a non-speculative version of code). Creating checkpoints includes saving register values to a storage (e.g., a memory) location representative of the state of the CPU before attempting to execute a speculative path. In some instances, register values to be saved to the storage location may require instruction calculation(s) to derive the register values. As such, creating checkpoints consumes both storage resources and CPU processing resources. In the event that the speculation was correct, the checkpoint information is no longer needed. Generally speaking, checkpointing result in two storage locations, one containing a speculative CPU state (e.g., speculative storage), and one containing a non-speculative CPU state (e.g., checkpoint storage) that can be restored in the event of an exception. Any register states stored in the non-speculative storage may be discarded in favor of using the speculative storage register states when speculation is correct. The example SES may perform a Commit operation to transfer the data from the speculative storage to the non-speculative storage. Typically, a Commit operation requires the architectural state to be precise, which prevents the SES from removing computed values in the precise state that may never be used in subsequent computations. In other words, when speculation is correct/successful, some CPU resources that are consumed to generate the full precise state may be wasted and/or result in work performed by the CPU that is never utilized. The methods and apparatus described herein employ, in part, partial commit-checkpoint operations to relax the precise architectural state constraints and enable more aggressive dynamic optimizations (e.g., across dynamic atomic regions). For example, the methods and apparatus described herein generate fixup code that may be executed only when necessary (e.g., after an exception occurs) rather than explicitly calculating a register state before storing to the non-speculative storage location(s). As a result, rather than consuming CPU cycles to calculate a precise register state prior to storage in the non-speculative storage location(s), an address of the generated fixup code, which is known a priori may be stored instead, thereby reducing CPU cycle consumption during the speculative execution process. FIG. 1 is a schematic illustration of an example platform 100 that may be used with the methods and apparatus described herein. In the illustrated example of FIG. 1 , the platform 100 includes a CPU 102 , a speculative execution system (SES) 103 , a memory 104 , a basic input/output system (BIOS) 106 , one or more input/output (I/O) device(s) 108 , hard disk drive (HDD) and/or optical storage 110 , a dynamic optimizer module (OPT) 112 , and a fixup module 114 . The example fixup module 114 may include the OPT 112 and the SES 103 , but is not limited as such. Additionally, the example SES 103 includes an example Checkpoint (K) logic module 120 , a Commit (C) logic module 122 , a Commit-Checkpoint (C k ) logic module 124 , and a recovery logic module 126 . Without limitation, the example platform 100 may include any number and/or type of elements other than those shown in FIG. 1 . In operation, the example CPU 102 executes code retrieved from the example memory 104 , the example BIOS 106 , the example I/O 108 (including sources external to the example platform 100 such as, but not limited to an intranet, the Internet, etc.), and/or the example HDD 110 . During code execution, the SES 103 may execute one or more dynamically optimized code regions, thereby minimizing instances of CPU stall. To ensure correctness, the example SES 103 may Checkpoint (e.g., via the example Checkpoint (K) logic module 120 ) the architectural state of the example CPU 102 , execute the optimized code, and Commit (e.g., via the example Commit (C) logic module 122 ) the speculative results after the execution is proven correct. However, in the event that the execution is incorrect (e.g., due to one or more exception(s)), the example SES 103 rolls the execution back by recovering the checkpoint (e.g., via the example Recovery logic module 126 ) and restarting execution with a more conservative (e.g., less speculative) execution. When the example OPT 112 identifies a region of code for optimization, the OPT 112 may analyze an instruction from the region to determine if it is a candidate instruction for fixup code. As described in further detail below, fixup code includes, but is not limited to pointers to executable instructions and/or executable instructions stored in a memory for later execution, if necessary. If candidate instructions for fixup code are found, the example OPT 112 generates a partial commit-checkpoint, generates fixup code, and the example fixup module 114 associates the address of the fixup code with the partial commit-checkpoint operation. In effect, the partial commit-checkpoint operation of the fixup module 114 enables the example platform 100 to perform a checkpoint operation without requiring a precise architectural state of the CPU 102 . In the event that the CPU precise architectural state needs to be restored (e.g., due to an exception), the example SES 103 references the address of the generated fixup code to calculate the precise register value corresponding to the optimized instruction(s). In other words, CPU resources directed to calculating the precise register value do not need to occur until after the exception condition is proven to be true. At least one benefit realized in view of the example partial commit-checkpoint operation implemented by the example fixup module 114 is a reduction in CPU resources that are otherwise consumed by executing all instructions associated with register value calculation(s). For instances where speculation is correct, the quantity and/or CPU burden is reduced by avoiding one or more calculations of all CPU register values. On the other hand, for instances where speculation is incorrect, the methods and apparatus described herein facilitate a mechanism to calculate a precise register state. While the illustrated example of FIG. 1 includes the OPT 112 and the fixup module 114 within the example platform 100 , the methods and apparatus described herein are not limited thereto. For example, the example SES 103 , OPT 112 and/or the example fixup module 114 may be located externally to the example platform, as shown in FIG. 2 . Alternatively, the example OPT 112 and/or the example fixup module 114 may be located external to the example CPU 102 as software and/or hardware, as shown in FIG. 3 . One or more descriptions of the methods and apparatus described herein will generally reference the example platform 100 as shown in FIG. 1 , but such descriptions are for purposes of illustration and not limitation. FIGS. 4 and 5 illustrate two examples that employ commit-checkpoint operations ( 400 , 500 ), the first of which (i.e., FIG. 4 ) may be employed by the CPU 102 to commit a speculative state generated by region A and create a traditional checkpoint, and the second of which (e.g., FIG. 5 ) is an example operation in view of the methods and apparatus described herein. In the illustrated example of FIG. 4 , a first atomic region A includes four instructions (i 1 , i 2 , i 3 , and i 4 ) and a second atomic region B includes two instructions (i 5 and i 6 ). FIG. 4 illustrates an example control flow graph (CFG), in which Atomic regions A and B may each be referred to as a node and paths of execution between nodes may be referred to as an edge (represented by an arrow). During one or more optimization processes executed by, for example, the OPT 112 of the CPU 102 , instructions may be analyzed to identify partially dead code (also referred to as partially dead instructions). As described herein, the example SES 103 includes a system that provides support for checkpoint, commit and/or recovery operations to enable speculative execution, but the example SES 103 is not limited thereto. Additionally, as described herein and in further detail below, the example OPT 112 facilitates, in part, dynamic optimization(s) and/or fixup code generation. In the event that a full precise architecture state is deemed necessary, the example SES 103 may invoke the fixup code after a Recovery operation(s). As described above, partially dead instructions are instructions that produce a value that may not be used by subsequent computation. Instructions that define architectural values that are not used by code in subsequent atomic regions are partially dead because they may still be needed by exception and/or interruption handlers executed between atomic regions. In the illustrated example of FIG. 4 , register R 1 is initially zero ( 402 ) and register R 2 is initially populated with a value of two ( 404 ) when entering atomic region A. Example instruction i 1 calculates a value for register R 1 as the existing value of register R 1 plus the integer two. Example instruction i 2 uses the calculated value of R 1 in its calculation to derive a value for register R 3 . Additionally, example instruction i 2 calculates a value for register R 3 , which uses the previously calculated value R 1 . Example instruction i 3 calculates a value for register R 4 that also uses the previously calculated value R 1 . Finally, example instruction i 4 in atomic region A calculates a value for R 2 , which uses value R 2 itself divided by the previously calculated value R 1 . Of the four example instructions i 1 , i 2 , i 3 and i 4 of atomic region A, only instructions i 2 and i 3 are considered partially dead code because their result has no further effect on either any other instruction within atomic region A or any subsequent atomic region(s). That is, the results computed by i 2 and i 3 cannot be used by computations executed after region B because region B overwrites the computed results when executing instruction i 5 and i 6 , but they may be required in the event that an exception and/or interruption is handled between regions A and B. In other words, if no extraordinary events (such as an interruption and/or exception) happen after region A commits and before region B commits, then instructions i 2 and i 3 are not required because their results will not be used. Nonetheless, in case of extraordinary events (e.g., exceptions), the CPUs have to provide a precise architectural state to an exception handler. This is usually realized by requiring that checkpoints reflect absolute state precision. In this example, each of instructions i 1 , i 2 , i 3 and i 4 are calculated to allow the precise values for R 1 , R 2 , R 3 and R 4 to be saved by the Commit-Checkpoint operation at i 4 . Checkpoint storage 406 shows the architectural state after the C k operation at i 4 . The end of an atomic region, such as the example atomic region A of FIG. 4 , may be terminated with a commit-checkpoint instruction (C k ) 408 , which is a representation of the end of an atomic region and the beginning of a new atomic region, and causes the CPU 102 to commit the speculative execution of the executed atomic region and record a new checkpoint to enable the speculative execution of the next region. Generally speaking, whenever a commit is performed, the effects of the instructions in the atomic region become visible to other devices (e.g., other processors), and corresponding effects (e.g., register updates, memory stores, etc.) are made permanent. Although commit marks are described herein, the methods and apparatus described herein are not limited thereto and may be applied to other atomic regions and/or commit models without limitation. Atomic region B represents a branch from atomic region A. In the illustrated example of FIG. 4 , atomic region B includes instruction i 5 to calculate a value for register R 4 and instruction i 6 to calculate an instruction for R 3 . As an exception may occur at any point of execution, providing a mechanism to commit-checkpoint with full precision facilitates, in part, an ability to recover in a safe manner. Additionally, the commit-checkpoint consumes CPU cycles by requiring calculation(s) for each register within any affected atomic region(s). The methods and apparatus described herein facilitate, in part, providing for full precision checkpointing and reducing CPU resource consumption during one or more checkpointing operation(s). The example atomic regions A and B and instructions i 1 , i 2 , i 3 , i 4 , i 5 and i 6 of FIG. 5 are substantially similar to the atomic regions and instructions in FIG. 4 . However, unlike the example of FIG. 4 , where the precise architectural state 406 is saved by the C k operation 408 , the illustrated example of FIG. 5 includes a partial commit-checkpoint 516 that saves part of the architectural state 512 and includes associated fixup code 514 that can be executed to recover the full (precise) architectural state in case it is needed. Instructions i 2 and i 3 in atomic region A of FIG. 5 are shown crossed-out as an indication of code that was removed by the example OPT 112 , thereby improving the execution by avoiding additional CPU cycles toward calculation of instructions i 2 and i 3 . However, to allow the recovery of the precise architectural state in the event of an exception occurring in atomic region B and/or anywhere between regions A and B, the fixup code 514 is created. The example partial commit-checkpoint instruction 516 causes the address(es) of the fixup code (fu_add) to be associated with the partial commit-checkpoint. In operation, the example partial commit-checkpoint operation 500 generates a non-precise checkpoint 510 by eliminating the computation of instructions i 2 and i 3 . The instructions associated with i 2 and i 3 may be copied from the atomic region A to the example fixup code 514 during the dynamic optimization. Unlike the identified partially dead instructions i 2 and i 3 , any remaining instructions are executed (i 1 and i 4 ) and their speculatively calculated values 514 are committed and saved by the partial commit-checkpoint at i 4 . As a result, CPU instructions that would have been consumed to calculate register values R 3 and R 4 are avoided, thereby improving a CPU utilization metric during region A execution. In other examples, an atomic region may execute over any number of iterations and/or in a loop. In the illustrated example of FIG. 6 , atomic region A includes instructions i 1 , i 2 , i 3 , i 4 and i 5 , and atomic region B includes instruction i 6 . While instruction i 4 calculates register value R 4 during each loop iteration, register R 4 is not used again in atomic region A and the computation represents wasted CPU cycles. The illustrated example of FIG. 7 shows how to improve the regions of FIG. 6 by, in part, removing instruction i 4 (see cross-out) and moving it to atomic region B, which does require register value R 4 when computing instruction i 6 . In this example, the value of register R 4 is only computed after leaving the loop, which may reduce the number of times that i 4 is executed. Although removal of instruction i 4 successfully saves CPU cycles from being consumed, such removal results in the commit-checkpoint operation of region A to save a processor state that lacks precision. In this example, if the state needs to be recovered to this checkpoint, the architectural state will not be precise. To allow the precise architectural state to be reconstructed when recovering the state saved by the partial commit-checkpoint, the methods and apparatus described herein permit fixup code to be generated for the removed instruction i 4 from atomic region A. As a result, when an exception occurs, a precise state of the CPU may be re-constructed during the recovery operation. For example, FIG. 8 illustrates fixup code 802 associated with fixup label fu 1 804 . The fixup code 802 represents instruction i 4 so that, in the event of recovery to the partial commit-checkpoint performed at i 5 in atomic region A, the precise state of register R 4 can be recovered. In case a recovery happens and the precise state is required, the example SES 103 can execute the associated fixup code 802 and reconstruct the full precise state. FIG. 9 is a schematic illustration of the example fixup module 114 , OPT module 102 and SES 103 of FIG. 1 . In the illustrated example of FIG. 9 , the fixup module 114 includes a fixup code generator 906 , a fixup code memory 912 , a fixup code fetch module 920 and a partial Commit-Checkpoint P(fu) logic module 918 . As described above in connection with FIG. 1 , the example SES 103 includes the Checkpoint (K) logic module 120 , the Commit (C) logic module 122 , the Commit-Checkpoint (C k ) logic module 124 and the recovery logic module 126 , and the example OPT 112 includes a dynamic optimizer 914 . The example fixup module 114 facilitates generation of fixup code in response to one or more requests. Requests to generate fixup code may be generated by the example dynamic optimizer 914 in response to receiving one or more indications to optimize code in a speculative manner. The example fixup code generator 906 may associate an address associated with candidate code with a fixup code label. Fixup code generated by the fixup code generator 906 and associated label(s) may be stored in the example fixup code memory 912 . While the example fixup code memory 912 is shown as part of the example fixup module 114 , the example fixup code memory 912 may be located elsewhere, without limitation. In operation, the example fixup module 114 may employ the partial commit-checkpoint logic module 918 in the example fixup module 114 to invoke a partial commit-checkpoint, as described above. In response to a request to invoke the fixup code, the example fixup code fetch module 920 queries and/or otherwise retrieves fixup code from the fixup code memory 912 that was previously generated by the example fixup code generator 906 . To provide support for Checkpoint (K), Commit (C), Commit-Checkpoint (Ck) and/or recovery operations, the example SES 103 invokes one or more of the example Checkpoint (K) logic module 120 , the example Commit (C) logic module 122 , the example Commit-Checkpoint (Ck) logic module 124 and/or the example recovery logic module 126 . In operation, in response to one or more requests from the example SES 103 , the example fixup code fetch module 920 queries and/or otherwise acquires fixup code from the example fixup code memory 912 . While the example platform 100 and fixup module 114 of FIGS. 1-3 and 9 have been shown to create partial commit-checkpoints to improve checkpoint creation speed and efficiency, one or more of the elements and/or devices illustrated in FIGS. 1-3 and 9 may be combined, divided, re-arranged, omitted, eliminated and/or implemented in any other way. Further, the example CPU 102 , SES 103 , memory 104 , BIOS 104 , OPT 112 , fixup module 114 , fixup code generator 906 , fixup code memory 912 , dynamic optimizer 914 , partial commit-checkpoint logic module 918 and/or fixup code fetch module 920 of FIGS. 1-3 and 9 may be implemented by one or more circuit(s), application specific integrated circuit(s) (ASIC(s)), programmable logic device(s) (PLD(s)), and/or field programmable logic device(s) (FPLD(s)), etc. When any of the appended apparatus claims are read to cover a purely software and/or firmware implementation, at least one of the example CPU 102 , SES 103 , memory 104 , BIOS 104 , OPT 112 , fixup module 114 , fixup code generator 906 , fixup code memory 912 , dynamic optimizer 914 , partial commit-checkpoint logic module 918 and/or fixup code fetch module 920 of FIGS. 1-3 and 9 are hereby expressly defined to include a tangible medium such as a memory, DVD, CD, etc. storing the software and/or firmware. Further still, the example CPU 102 , SES 103 , memory 104 , BIOS 104 , OPT 112 , fixup module 114 , fixup code generator 906 , fixup code memory 912 , dynamic optimizer 914 , partial commit-checkpoint logic module 918 and/or fixup code fetch module 920 of FIGS. 1-3 and 9 may include one or more elements, processes and/or devices in addition to, or instead of, those illustrated in FIGS. 1-3 and 9 , and/or may include more than one of any or all of the illustrated elements, processes and devices. FIGS. 10-12 illustrate example processes that may be performed to implement the example SES 103 , OPT 112 and fixup 114 modules of FIGS. 1-3 and 9 . The example processes of FIGS. 10-12 may be carried out by a processor, a controller and/or any other suitable processing device. For instance, the example processes of FIGS. 10-12 may be embodied in coded instructions stored on any tangible computer-readable medium such as a flash memory, a CD, a DVD, a floppy disk, a read-only memory (ROM), a random-access memory (RAM), a programmable ROM (PROM), an electronically-programmable ROM (EPROM), and/or an electronically-erasable PROM (EEPROM), an optical storage disk, an optical storage device, magnetic storage disk, a magnetic storage device, and/or any other medium that can be used to carry or store program code and/or instructions in the form of machine-readable instructions or data structures, and that can be accessed by a processor, a general-purpose or special-purpose computer, or other machine with a processor (e.g., the example processor platform P 100 discussed below in connection with FIG. 13 ). Combinations of the above are also included within the scope of computer-readable media. Machine-readable instructions comprise, for example, instructions and/or data that cause a processor, a general-purpose computer, a special-purpose computer, or a special-purpose processing machine to implement one or more particular processes. Alternatively, some or all of the example processes of FIGS. 10-12 may be implemented using any combination(s) of ASIC(s), PLD(s), FPLD(s), discrete logic, hardware, firmware, etc. Also, one or more operations of the example processes of FIGS. 10-12 may instead be implemented manually or as any combination of any of the foregoing techniques, for example, any combination of firmware, software, discrete logic, and/or hardware. Further, many other methods of implementing the example operations of FIGS. 10-12 may be employed. For example, the order of execution of the blocks may be changed, and/or one or more of the blocks described may be changed, eliminated, sub-divided, or combined. Additionally, any or all of the example processes of FIGS. 10-12 may be carried out sequentially and/or carried out in parallel by, for example, separate processing threads, processors, devices, discrete logic, circuits, etc. The example processes of FIG. 10 include a checkpoint logic process 1000 , a commit logic process 1004 , a commit-checkpoint logic process 1008 , a partial commit-checkpoint logic process 1014 , and a recovery logic process 1022 . The example checkpoint logic process 1000 , which may be executed by the example checkpoint logic module 120 of FIGS. 1-3 and 9 , saves a current architectural state of a CPU (block 1002 ). The example commit logic process 1004 , which may be executed by the example commit logic module 122 of FIGS. 1-3 and 9 , commits any speculative data that may have been saved to a storage (e.g., a memory) during one or more speculation operation(s) (block 1006 ). The example commit-checkpoint logic process 1008 , which may be executed by the example commit-checkpoint logic module 124 of FIGS. 1-3 and 9 , commits any speculative data (block 1010 ), and then saves the currently architectural state of the CPU (block 1012 ). Unlike traditional speculation approaches, the example partial commit-checkpoint logic process 1014 , which may be executed by the example fixup module(s) 114 and/or the example partial commit-checkpoint 918 of FIG. 9 , commits any speculative data to a memory (block 1016 ) and saves an architectural state of the CPU (block 1018 ). Thereafter, the example process 1014 annotates the recently created checkpoint as a partial commit-checkpoint and associates it with fixup code (fu) (block 1020 ). The example fixup code (fu) may be created by the example fixup code generator 906 , as shown in FIG. 9 . During instances in which a recovery operation occurs (block 1022 ), which may be executed by the example recovery logic module 126 , any speculative data that was previously stored is discarded (block 1024 ). To allow further safe operation of the CPU, the state of the CPU at the checkpoint is loaded (block 1026 ) and the example fixup code fetch module 920 determines whether the previously saved state is also a partial commit-checkpoint (block 1028 ). If not, then control advances in a traditional manner, otherwise the fixup code fetch module 920 invokes any fixup code (fu) associated with the partial commit-checkpoint (block 1030 ) to obtain full precision. FIG. 11 illustrates an example process 1100 of CPU execution in view of the methods and apparatus described herein. If no checkpoint operation occurs (block 1102 ), then instructions are executed in a non-speculative manner (block 1104 ). On the other hand, in the event of a checkpoint operation (block 1102 ), checkpoint logic may be executed (block 1106 ) and one or more instructions may be executed in a speculative manner (block 1108 ). In the event of an exception (block 1110 ), the example recovery logic module 126 may initiate a recovery of the architectural state (block 1112 ) and handle the exception (block 1114 ), as described in the example process 1022 of FIG. 10 . On the other hand, if there is no exception (block 1110 ), the example SES 103 determines if a checkpoint operation of type commit-checkpoint (C k ) was to be executed (block 1116 ). If so, then the example commit-checkpoint logic module 124 may execute commit-checkpoint logic (block 1118 ), such as by way of the example process 1008 of FIG. 10 . If the example SES 103 determines that a checkpoint of type partial commit-checkpoint was to be executed (block 1120 ), then the example partial commit-checkpoint logic module 918 may execute partial commit-checkpoint logic (block 1122 ), such as by way of the example process 1014 of FIG. 10 . In the event that the example SES 103 determines the occurrence of a commit operation (block 1124 ), then the example commit logic module 124 may execute the example process 1004 of FIG. 10 (block 1126 ). In case none of the previous operations are detected, the SES 103 may proceed by speculatively executing more instructions (block 1108 ). The methods and apparatus described herein also improve one or more optimization techniques (e.g., partial dead code elimination (PDE)) that may be employed by processors and/or platforms. Generation of fixup code and analysis of executable code, such as analysis of one or more control flow graphs (CFGs), may be realized by the example OPT 112 . Traditional optimization techniques typically evaluate a single atomic region node at a time, but cannot perform one or more evaluative optimizations across multiple nodes. To facilitate, in part, optimization across regions (nodes), the example dynamic optimizer 914 analyzes a CFG node for instances of a checkpoint operation, such as a commit-checkpoint operation (C k ). In response to detecting the checkpoint operation, the example dynamic optimizer 914 generates a placeholder block and connects the block that contains the checkpoint operation to the placeholder block by using a control flow edge before moving on to another CFG node, if any. When any number of CFG nodes have been analyzed to detect instances of a checkpoint operation, the example dynamic optimizer 914 proceeds with the optimization. During optimization, the example dynamic optimizer 914 may identify partially dead code candidates and move code from one node to another node to optimize one or more paths (edges). For example, a generated node may be an atomic region or one of the placeholder blocks inserted previously by the example dynamic optimizer 914 . When the optimization is complete, the example OPT 112 invokes the example dynamic optimizer 914 to identify which placeholder blocks are still empty (e.g., the optimization technique employed did not identify any changes to further optimization), and which placeholder blocks are populated with code after the optimization. Empty placeholder blocks may be removed because, in part, they have no further use for the optimization. However, placeholder blocks that are not empty are indicative of an architectural state that is no longer precise in response to a checkpoint operation (e.g., C k ). The non-empty placeholder blocks contain instructions that, when executed, fix and/or otherwise ensure a precise architectural state associated with the checkpoint operation. In this sense, the example dynamic optimizer 914 modifies the optimized code by promoting the non-empty block to contain fixup code and by replacing the commit-checkpoint operation by a partial commit-checkpoint P(fu) with associated fixup code fu. FIG. 12 illustrates an example process 1200 that may be realized by the methods and apparatus described herein. The example process 1200 of FIG. 12 begins with identifying candidate control flow graphs (CFGs) for optimization (block 1202 ). Any number of sections, regions and/or portions of a CFG may be identified by the example OPT 112 . A node from the CFG is selected (block 1204 ), in which each node may include any number of instructions, and a checkpoint operation is located within the selected node to create a placeholder block (B i ) (block 1206 ). Each example node from the example CFG may be designated with an identifier i. As such, the example nomenclature B i refers to a placeholder block associated with the i th node. The example dynamic optimizer 914 creates a control flow edge from the i th node containing the checkpoint operation and points to (i.e., directs control flow toward) the placeholder block (B i ) (block 1208 ). In the event that the example CFG and/or subset of CFGs include additional nodes (block 1210 ), then control returns to block 1204 . In the event that the example CFG and/or subset of CFGs do not include any additional nodes that have not already been analyzed by the example dynamic optimizer 914 (block 1210 ), then one or more compiler optimization(s) are allowed to proceed (block 1212 ). Any type of compiler optimization may occur including, but not limited to forward code motion optimization(s) and/or partial dead code elimination optimization(s). The example dynamic optimizer 914 selects a node from the optimized CFG and/or subset of CFGs (block 1214 ), such as the i th node. If the placeholder block (B i ) associated with the ith node is empty (block 1216 ), then B i is removed from the i th node (block 1218 ). If the optimized CFG and/or subset of CFGs include additional nodes that have not yet been analyzed (block 1220 ), then control returns to block 1214 to select another node. However, if Bi is not empty (block 1216 ), which is indicative of a circumstance where an architectural state is no longer precise in response to a checkpoint operation (e.g., C k ), then the example dynamic optimizer 914 creates fixup code FU i and associates it with label fu i (block 1222 ). Additionally, any instructions that are contained within B i based on the prior optimization are copied to FU i (block 1224 ), and the checkpoint previously located in the i th node is replaced with a partial commit-checkpoint P i (fu i ) (block 1226 ). If the optimized CFG and/or subset of CFGs include additional nodes that have not yet been analyzed (block 1220 ), then control returns to block 1214 to select another node, otherwise the example process 1200 ends. FIG. 13 is a schematic diagram of an example processor platform P 100 that may be used and/or programmed to implement any or all of the example CPU 102 , SES 103 , memory 104 , BIOS 104 , OPT 112 , fixup module 114 , fixup code generator 906 , fixup code memory 912 , dynamic optimizer 914 , partial commit-checkpoint logic module 918 and/or fixup code fetch module 920 of FIGS. 1-3 and 9 . For example, the processor platform P 100 can be implemented by one or more general-purpose processors, processor cores, microcontrollers, etc. The processor platform P 100 of the example of FIG. 13 includes at least one general-purpose programmable processor P 105 . The processor P 105 executes coded instructions P 110 and/or P 112 present in main memory of the processor P 105 (e.g., within a RAM P 115 and/or a ROM P 120 ). The processor P 105 may be any type of processing unit, such as a processor core, a processor and/or a microcontroller. The processor P 105 may execute, among other things, the example processes of FIGS. 10-13 to implement the example methods and apparatus described herein. The processor P 105 is in communication with the main memory (including a ROM P 120 and/or the RAM P 115 ) via a bus P 125 . The RAM P 115 may be implemented by dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), and/or any other type of RAM device, and ROM may be implemented by flash memory and/or any other desired type of memory device. Access to the memory P 115 and the memory P 120 may be controlled by a memory controller (not shown). The example memory P 115 may be used to implement the example fixup code memory 912 . The processor platform P 100 also includes an interface circuit P 130 . The interface circuit P 130 may be implemented by any type of interface standard, such as an external memory interface, serial port, general-purpose input/output, etc. One or more input devices P 135 and one or more output devices P 140 are connected to the interface circuit P 130 . Although certain example methods, apparatus and articles of manufacture have been described herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus and articles of manufacture fairly falling within the scope of the appended claims either literally or under the doctrine of equivalents.

Example methods and apparatus to manage partial commit-checkpoints are disclosed. A disclosed example method includes identifying a commit instruction associated with a region of instructions executed by a processor, identifying candidate instructions from the region of instructions, and generating a processor partial commit-checkpoint to save a current state of the processor, the checkpoint based on calculated register values associated with live instructions, and including instruction reference addresses to link the candidate instructions.

BACKGROUND As is known in the art, phased array radar systems require extensive and costly signal processing hardware and software in order to meet real-time requirements. Existing radar signal processors rely on custom built and/or specialized high-end, limited volume equipment, resulting in high capital outlay, integration and validation costs. To process large amounts of data on such systems, programmers must write code that distributes the elements of a function to multiple processors. This is an expensive process that requires specialized processing tool kits and expertise. SUMMARY It is appreciated herein that it would be desirable to provide a system for processing radar signal data having a scalable architecture based upon commercial off-the-shelf (COTS) hardware and/or software. Accordingly, a system for processing radar data comprises a plurality of detector signal data processors (SDPs) coupled to receive radar data and to generate detection data, each of the detector SDPs comprising at least one processor and a plurality of data processing units (DPUs) executing on the processor, each of the DPUs comprising an input port, a queue, a filter, and an output port, each of the DPUs to receive data into the queue via the input port, to determine data is available in the queue, to remove the available data from the queue, to process the available data using the filter, and to output the processed data at the output port. The system may further comprise an aggregator SDP coupled to receive detection data from two or more of the plurality of detector SDPs and, in response thereto, to generate a stream of plot information based upon the received detection data. In embodiments, the system also comprises a radar tracker or other external system coupled to receive the stream of plot information from the data aggregation processor. It will be appreciated that the system provides high-throughput radar signal processing without resorting to relatively expensive parallel processing tool kits. The system breaks the signal processing chain into a series of independent data processing units (DPUs) that can execute independently and in parallel. Queuing theory is used to efficiently distribute processing across multiple processor cores and/or computers. The system scales to an arbitrary number of cores/computers. The independent nature of the DPUs readily allows addition/replacement of new filters into the system. In some embodiments, the system further comprises a multiplexer coupled to receive the radar data and to select one of the plurality of detector SDPs to process the received radar data. In certain embodiments, the aggregator SDP comprises a demultiplexer to correlate and aggregate the received detection data. In some embodiments, at least one of the plurality of detector SDPs comprises a plurality of DPUs arranged in series. In embodiments, at least one of the plurality of detector SDPs comprises a DPU having an impulsive interference filter (IIF), a DPU having a Doppler filter, a DPU having a clutter filter, and a DPU having a constant false alarm rate (CFAR). In certain embodiments, the aggregator SDP further comprises a plot extractor. In some embodiments, the aggregator SDP comprises a data formatter to generate the stream of plot information according to the Structured Eurocontrol Surveillance Information Exchange (ASTERIX) standard. The plurality of detector SDPs and the aggregator SDP may be coupled via a packet-switched network and the aggregator SDP may be coupled to the radar tracker via a radar data network. In some embodiments, at least one of the detector SDPs further comprises an ingest module to receive the radar data via the packet-switched network and to copy the received radar data to the queue of at least one of the respective DPUs. In particular embodiments, a radar comprises a phased array antenna, wherein the radar data comprises blocks of data having associated elevation angles, wherein the multiplexer selects one of the plurality of detector SDPs based upon an elevation angle associated with the received radar data. In embodiments, at least one of the detector SDPs comprises two or more DPUs configured to execute on separate threads and/or as separate processes. The DPUs may use a semaphore to determine data is available in a queue. According to another aspect, a method for processing radar data comprises receiving radar data, moving the radar data to a first queue, determining the radar data is available in the first queue, removing the radar data from the first queue, processing the radar data using a first filter to generate first processed data, moving the first processed data to a second queue, determining the first processed data is available in the second queue, removing the first processed data from the second queue, processing the first processed data using a second filter to generate second processed data, performing plot detection on the second processed data to generate detection data, aggregating the detection data with other detection data to generate aggregate detection data, and performing plot extraction on the aggregate detection data to generate a stream of plot information. In some embodiments, the method further comprises providing the stream of plot information to a radar tracker. The method may employ various filters, such as an IIF, a Doppler filter, a clutter filter, a CFAR, a cell-averaging CFAR, an ordered statistic CFAR, a binary integrator, a beamformer, or an external interference cancellation filter. In embodiments, at least two different steps of the method are executed on separate threads. For example, moving radar data to a first queue may be executed on a first thread, whereas processing the radar data using a first filter to generate first processed data may be executed on a second thread. In some embodiments, determining the radar data is available in the first queue comprises reading the value of a semaphore. In some embodiments, the system and/or method may be used to process radar data comprising blocks of digital pulse compressed data. BRIEF DESCRIPTION OF THE DRAWINGS The concepts, structures, and techniques sought to be protected herein may be more fully understood from the following detailed description of the drawings, in which: FIG. 1 is a block diagram of an illustrative data processing unit (DPU); FIG. 1A is a block diagram of an illustrative arrangement of DPUs; FIG. 2 is a block diagram of an illustrative system including signal data processors (SDPs) operatively coupled to a radar; FIG. 3 is an isometric view of an active, electronically scanned array (AESA) having a panel architecture; and FIG. 4 is a schematic representation of an illustrative computer for use with the systems of FIGS. 1, 1A , and/or 2 . The drawings are not necessarily to scale, or inclusive of all elements of a system, emphasis instead generally being placed upon illustrating the concepts, structures, and techniques sought to be protected herein. DETAILED DESCRIPTION Referring to FIG. 1 , a data processing unit (DPU) 100 provides an independently and loosely coupled processing function within a signal data processing system. The illustrative DPU 100 includes an input port 102 , a queue 104 , a filter 106 , and an output port 108 . The queue 104 may use a first-in first-out (FIFO) policy, a priority-based policy, or any other suitable queuing policy known in the art. The filter 106 may be provided from any suitable combination of hardware and/or software to provide a DPU 100 having a desired signal data processing function. In some embodiments, the filter 106 comprises an impulsive interference filter (IIF), a Doppler filter (e.g., a 5-bin or 256-bin Doppler filter), a clutter filter, a constant false alarm rate (CFAR), a cell-averaging CFAR (e.g., operating on 5-bin or 256-bin Doppler filtered data), an ordered statistic CFAR (e.g., operating on 256-bin Doppler filtered data), a binary integrator, a plot extractor, a beamformer (e.g., deriving 64, or 128 azimuth beams), and/or an external interference cancellation. The input port 102 and output port 108 may represent any suitable data transfer mechanisms. For example, if the DPU 100 is provided as an object (in the object-oriented programming sense), the input port 102 may correspond to a message receiver and the output port 108 may correspond to a message sender. If the DPU 100 is provided as an application program (or “software application”) configured to execute upon a general-purpose computer (e.g., an x86-based computer), the ports 102 , 108 may correspond to inter-process communication (IPC) mechanisms available on the computer's operating system (OS), such as UNIX pipe, shared memory, or a file. If the DPU 100 is provided as a network service, the ports 102 , 108 may correspond to network endpoints. In general operation, the DPU 100 receives data into the queue 104 via the input port 102 . In some embodiments, the received data comprises one or more blocks of data. In certain embodiments, blocks of received data generally have the same fixed size. In some embodiments, the received data comprises one or more blocks of digital pulse compressed data generated by a radar. The radar may generate a stream of such blocks representative of pulse information transmitted and received by the radar. The received data is added (e.g., copied) to the queue 104 . In some embodiments, two or more threads can access the queue 104 concurrently and, therefore, a mutual exclusion object (“mutex”), semaphore, or other suitable thread safety mechanism may be employed before the received data is added to the queue. Those skilled in the art will understand that a mutex is a mechanism by which multiple threads within a program can share a resource while preventing that multiple threads do not access the resource simultaneously. Non-limiting examples of shared resources include files and memory. A mutex may be initialized when a program starts up and before threads are initialized. During initialization, a mutex is typically assigned a name that is unique within the program. Subsequently, any thread that needs to access the shared resource must obtain a “lock” on mutex; when one thread has a lock on a mutex, other threads are prevented from accessing the resource. Accordingly, a thread should “unlock” the mutex (i.e., release its lock on the mutex) when it has completed accessing the shared resource. The queue maintains data which has not yet been processed by the DPU 100 (referred to herein as “available data”). In an asynchronous manner, the DPU 100 determines that data is available in the queue 104 , removes the available data from the queue, and processes the available data using the filter 106 . In some embodiments, a semaphore is used to notify the DPU of available data, as described further in conjunction with FIG. 1A . Similar to adding data to the queue, a mutex or other thread safety mechanism may be employed before data can be safely removed from the queue. Once processing is complete, the processed data is provided via the output port 108 . Those skilled in the art will understand that the act of attempting to read the semaphore causes a reading thread to block until the semaphore is signaled by another thread (e.g., via the act of moving data into the queue). Advantageously, such blocking action causes the OS to schedule execution of another thread that is not blocked, thereby making more efficient use of available resources. In other words, execution of a given thread is inhibited until such time as data is available, giving priority to threads (and thus DPUs) having data available. Referring to FIG. 1A , an illustrative arrangement of DPUs includes a first DPU 100 a operatively coupled to receive data (e.g., radar signal data) from an external data source (not shown); second and third DPUs 100 b , 100 c operatively coupled to receive data from the first DPU 100 a ; and a fourth DPU 100 d operatively coupled to receive data from the second and third DPUs and operatively coupled to provide data to an external data sink (not shown). Any of the DPUs 100 a - 100 d may be the same as or similar to DPU 100 of FIG. 1 . In general, a DPU can receive input from one or more other DPUs (or external data sources) and can provide output to one or more other DPUs (or external data sinks). Thus, DPUs can be arranged in parallel, in series (e.g., to form a pipeline), or in any combination thereof. The DPUs 100 a - 100 d may be connected using hardware-based connections, software-based connections, or a combination of both hardware and software. Although FIG. 1A shows a particular arrangement of four DPUs, it should be understood that the concepts and techniques sought to be protected herein can be applied to any number of DPUs arranged in any desired configuration. Each of the DPUs 100 a - 100 d is generally self-contained, meaning that processing performed by one DPU does not depend upon processing performed by other DPUs. Any dependency between DPUs is managed at the system topology level via input and output port coupling. In addition, because the DPUs employ input queues, there are no timing dependencies between DPUs or other synchronization concerns. In particular embodiments, two or more of the DPUs 100 a - 100 d are provided within a common software application upon a multi-threaded OS (e.g., Linux). Here, each of the DPUs executes on a designated thread, and the OS schedules thread execution. It will be appreciated that this technique breaks data processing (e.g., radar signal data processing) into a sequence of independent processing steps (i.e., filters) and leverages existing OS schedulers to distribute these algorithms within a multi-core computer, providing high-throughput. In some embodiments, the common software application includes a dedicated thread (referred to herein as the “parent thread”) responsible for managing (e.g., “spawning” and “reaping”) child threads designated for the DPUs. In one embodiment, the parent thread is responsible for receiving input data from an external data source (e.g., a radar) and moving (e.g., copying) the input data to the first DPU 100 a . For example, as data arrives from the external data source, the parent thread moves the data to first DPU 100 a 's queue and notifies the first DPU 100 a that data is available (e.g., by incrementing a semaphore associated with the queue 104 ). In embodiments, the threads comprise Portable Operating System Interface (POSIX) threads (“pthreads”). In some embodiments, the DPUs 100 a - 100 d are provided as two or more processes configured to execute concurrently on a multitasking OS (e.g., Linux). Each of the DPUs executes within a designated process, and the OS manages process scheduling. Here, any suitable IPC technique can be used to move (e.g., copy) data between processes and provide notification of available data. In yet another embodiment, two or more of the DPUs 100 a - 100 d execute on different virtual and/or physical computing platforms. Here, any suitable networking protocols can be used to move data between the remote processes and provide notification of available data. It will be appreciated that any of the above parallel processing techniques (i.e., multi-threading, multitasking, and or using multiple computing platforms) can be combined to provide a signal data processing system that scales to any arbitrary number of processor cores and computers without requiring custom hardware or complex parallel processing software. Referring to FIG. 2 , an illustrative system 200 includes a radar 202 operatively coupled to a multiplexer 206 via a first signal path 204 , one or more signal data processors (SDPs) 210 operatively coupled to the multiplexer 206 via a second signal path 208 , and a radar tracker 214 operatively coupled to one or more of the SDPs via a third signal path 212 . The signal paths 204 , 208 , 212 are provided as any suitable combination of hardware and/or software-based signal paths. In embodiments, one or more of the signal paths 204 , 208 , 212 may include a network (or a portion thereof) operating, for example, using a packet-switched protocol (e.g., Internet Protocol (IP), Transmission Control Protocol (TCP), TCP/IP, etc.). Such a network may include relays, switches, routers, and the like. In a particular embodiment, signal paths 204 and 208 correspond to high-speed, dedicated packet-switched networks and the signal path 212 corresponds to a radar data network known in the art. In embodiments, the radar 202 is located upon a mobile platform (e.g., a land vehicle, an aircraft, or an unmanned aerial vehicle (UAV)) coupled to a remote situational display (e.g., located within a base station) via a wireless communication link. Because the bandwidth in such a link may less than that required to transmit “raw” radar pulse data, one or more SDPs 210 may be collocated with the radar upon the mobile platform. Thus, the mobile SDPs 210 analyze the radar pulse data to generate relatively low bandwidth track information which can be transmitted to the remote situational display. The illustrative system 200 includes four SDPs: a first SDP 210 a , a second SDP 210 b , a third SDP 210 c , and a fourth SDP 210 d ; in general, any number of SDPs greater than zero may be used. In embodiments, each of the SDPs 210 corresponds to a separate physical and/or virtual computing platform (e.g., a general-purpose computer comprising a multitasking, multi-threaded OS, such as Linux). In other embodiments, two or more SDPs 210 correspond to application processes executing on a common computing platform having a multitasking OS. In yet another embodiment, at least one of the SDPs 210 is provided across multiple computing platforms. As shown, a plurality of the SDPs (e.g., SDPs 210 a - 210 c ) receive data (e.g., digital pulse data) from the radar 202 via the multiplexer 206 and, therefore, are referred to herein as “detector SDPs.” In contrast, at least one of the SDPs (e.g., SDP 210 d ) receives data from more than one source (e.g., one SDP may receive detection data from two or more detector SDPs 210 a - 210 c ) and, therefore, is referred to herein as the “aggregator SDP.” In general, each of the detector SDPs 210 a - 210 c have generally the same components and functionality; thus, for clarity and simplicity of explanation, only the detector SDP 210 a will be described in detail herein. The detector SDPs 210 a , 210 b , and 210 c are coupled to the aggregator SDP 210 d via respective signal paths 209 a , 209 b , and 209 c . In some embodiments, the signal paths 209 a - 209 c and the signal path 208 correspond to portions of the same packet-switched network. The representative detector SDP 210 a comprises an ingest module 216 operatively coupled to receive data (in this example, digital pulse data) from the multiplexer 206 . A plurality of DPUs generally denoted 218 are operatively coupled to receive the pulse data from the ingest module 216 , and an output module 220 is operatively coupled to receive processed data from the plurality of DPUs 218 . A detection output module 222 is operatively coupled to receive processed data from the output module 220 and to transmit detection data to the aggregator SDP 210 d via the signal path 209 a . The various components 216 - 222 are operatively coupled via any combination of hardware and/or software-based signal paths. The representative detector SDP 210 a may include additional components and/or signal paths that are optional, unused, or disabled (e.g., the components shown with hatching in FIG. 2 ). The reason for this is discussed below in conjunction with the aggregator SDP 210 d. Although the concepts and techniques sought to be protected herein are not limited to performing any particular or specific type of processing, in one embodiment the DPUs 218 comprise an IIF 218 a , a Doppler filter 218 b , a clutter filter 218 c , a CFAR 218 d , and a binary integrator 218 e , as shown, to perform a technique for processing radar data. For simplicity of explanation, the DPUs 218 a - 218 e are referred to herein by the name of their respective filters, although it will be understood that the DPUs typically include additional elements, as shown in FIG. 1 . The DPUs 218 a - 218 e may be arranged in series to form a pipeline, as shown, with a first end of the pipeline (i.e., the IIF 218 a ) coupled to receive data from the ingest module 216 and a second end of the pipeline (i.e., the binary integrator 218 e ) coupled to the output module 220 . In embodiments, the detection output module 222 is also implemented as a DPU (i.e., the functionality described herein with respect to this module may be implemented within a DPU filter 106 of FIG. 1 ). Any of the plurality of DPUs 218 may be the same as or similar to the DPU 100 of FIG. 1 . An illustrative aggregator SDP 210 d comprises an ingest module 224 operatively coupled to receive detection data from the detector SDPs 210 a , 210 b , and 210 c via the respective signal paths 209 a , 209 b , and 209 c . The aggregator SDP 210 d further comprises a demultiplexer 226 operatively coupled to receive detection data from the ingest module, a plot extractor 228 operatively coupled to receive aggregate data from the demultiplexer 226 , an output module 230 operatively coupled to receive plot data from the plot extractor 228 , and a plot translation module 232 operatively coupled to receive plot data from the output module 230 . The various components 224 - 232 are connected via any combination of hardware and/or software-based signal paths. The plot translation module 232 receives combined detections from the plot extractor 228 and translates that information to the ASTERIX format, which may be received and used by external systems known in the art, such as the radar tracker 214 . The output module 230 may be the same as or similar to output module 220 within the detector SDP 220 a ; however, whereas the module 220 is configured to send data to the detection output module 222 , the module 230 is configured to send data to the plot translation module 232 , as shown. In embodiments, the plot extractor 228 and/or plot translation module 232 are implemented as DPUs (i.e., the functionality described herein with respect to these components may be implemented within a DPU filter 106 ( FIG. 1 ). In some embodiments, the detector SDPs 210 a - 210 c and the aggregator SDP 210 d generally include the same components and signal paths, although certain components may be unused or disabled (e.g., the components shown with hatching in FIG. 2 ). However, these different types of SDPs operate differently as a result of different configurations and/or different inputs. For example, the aggregator SDP 210 d may include a plurality of DPUs 218 ′ coupled to second ingest module 216 ′, however these DPUs are effectively disabled because the multiplexer 206 is not configured to transmit pulse data to the second ingest module 216 ′. It will be appreciated that by providing the same components in each of the SDPs 210 , the SDPs are generally interchangeable and setup and maintenance costs may be reduced. In other embodiments, an SDP 210 includes only those components and signal paths that are needed for its intended operation and, therefore, the components shown with hatching FIG. 2 may be omitted. In operation, the radar 202 transmits RF signals (e.g., pulse signals), typically using a modulation scheme as is generally known. The radar 202 receives analog signals comprising echo signals (“echos”) as well as clutter. The received analog signals are encoded using digital pulse compression coding known in the art. The encoded pulse data formatted for transmission via the signal path 204 using any suitable transmission protocol. For example, the radar 202 may segment (or “chunk”) the encoded pulse data into blocks for transmission through a packet-switched network. In embodiments, the blocks of encoded data are transmitted within IP packets, TCP/IP packets, etc. In embodiments, metadata is transmitted along with the pulse data for use by the SDPs 210 . The metadata can include, but is not limited to, the time the pulse data was generated by the radar 202 , the orientation of the radar antenna at the time the data was generated, and/or other state information regarding the radar. The multiplexer 206 receives encoded pulse data from the radar 202 , selects a target detector SDP 210 a - 210 c to process the received data, and transmits the received data to the target SDP via the signal path. This process may be repeated for each block of pulse data received. The target SDP 210 a - 210 c is selected using any suitable load balancing technique. In some embodiments, the multiplexer 206 uses a simple round-robin load balance technique. In other embodiments, the multiplexer 206 actively monitors the SDPs 210 a - 210 c to provide fault tolerance and/or dynamic load balancing. In some embodiments, the radar 202 includes an array (e.g., the active electronically steered array (AESA) of FIG. 3 ) having a plurality of subassemblies (e.g., subassemblies 314 a - 314 h of FIG. 3 ). By adjusting the phase of the signal transmitted/received by each individual element, the array is capable of producing and steering a beam having defined center angles of azimuth and elevation, and having defined angular width and height. In this case, the radar 202 transmits metadata identifying a corresponding beam azimuth and elevation angles. In turn, the multiplexer 206 can use the azimuth/elevation information to select target detector SDPs. This allows individual detector SDPs 210 a - 210 c to retain spatial awareness across radar scans without having to communicate with other detector SDPs 210 a - 210 c . For example, assuming radar 202 produces beams using twelve elevations numbered 1-12, the multiplexer 202 may target elevations 1-4 to SDP 210 a , elevations 5-8 to SDP 210 b , and elevations 9-12 to SDP 210 c. Next, the selected target detector SDP (e.g., SDP 210 a ), or more specifically the ingest module 216 therein, receives encoded pulse data from the radar 202 via the multiplexer 206 and signal path 208 . In embodiments, the ingest module 216 comprises a network service to receive pulse data from the network and to copy the received data to the queue of the first DPU in the pipeline (i.e., to the queue of the IIF 218 a ). In various embodiments, the ingest module 216 performs error checking and/or correction to handle communication errors (e.g., dropped packets, out-of-order packets, etc.) introduced by the radar 202 and/or networks 204 , 208 . Next, the pulse data is processed by each of the DPUs 218 , as described above in conjunction with FIG. 1A , to generate processed data. Advantageously, two or more of the DPUs 218 can process signal data concurrently, relying on a multitasking/multi-threading OS to schedule the work, thus improving throughput performance. Next, the output module 220 , which is coupled to the output port 108 ( FIG. 1 ) of the binary integrator 218 e , transfers the processed data to the detection output module 222 . The detection output module 222 sends detections (i.e., candidate targets) represented by the processed data provided by the plurality of DPUs 218 to the aggregator SDP 210 d. The aggregator SDP 210 d , or more specifically the ingest module 224 therein, receives detection data from one or more of the detector SDPs 210 a - 210 c via a respective signal path 209 a - 209 c . As with the ingest module 216 described above, the ingest module 224 may comprise a network service. In embodiments, the ingest module 216 listens on a first network port and the ingest module 224 listens on a second different network port. The demultiplexer 226 receives detection data from the ingest module 224 and applies correlation and aggregation techniques to generate aggregate data suitable for performing plot extraction. In one embodiment, the demultiplexer 226 uses the metadata (e.g., a radar beam azimuth and elevation angles) to reconstruct data corresponding to the full radar aperture from blocks of data corresponding to sub-apertures of the radar. It should be understood that the system 200 generally does not provide real-time behavior and, for example, unpredictable delays may be introduced by the various signal paths and processing steps. Thus, to effectively correlate processed data in time, the demultiplexer 226 may collect blocks of data (e.g., using a buffer, a bounded buffer, etc.) and perform correlation/aggregation only when a sufficient number of blocks are received for a given time period. The plot extractor 228 receives aggregate data from demultiplexer 226 and outputs a stream including digital representations of plots using any suitable technique known in the art. The plot translation module 232 receives plot information from the plot extractor 228 and formats the data for transmission through the network 212 , which may comprise a radar data network. In some embodiments, the data is formatted according to the All Purpose Structured Eurocontrol Surveillance Information Exchange (ASTERIX) standard. As is known in the art, the formatted data may be used by a radar tracker 214 via the network 212 to form and update target tracks. Referring to FIG. 3 , the systems and techniques described above in conjunction with FIGS. 1, 1A, and 2 may be used in a radar system which includes an active electronically steered array (AESA) 300 . In some embodiments, the AESA 300 includes an antenna panel 312 (also referred to as a “panel array”) coupled to an integrated panel array assembly (IPAA) 314 . Antenna panel 312 is thin and generally planar and has a plurality of antenna elements generally denoted 313 , disposed to transmit and receive RF energy through a first surface 312 a thereof. Antenna elements 313 are shown in phantom since they are typically below external surface 312 a and thus not directly visible in FIG. 3 . In one example, the antenna elements 313 may be provided as a stacked patch antenna antenna elements configured for operation in the X-band frequency range and panel array is provided having a thickness, T in the range of about 0.003 meter (m) to about 0.01 m (with a thickness typically of about 0.005 m being preferred) and having a width, W, of about 0.5 m and a length, L, of about 0.5 m with 1024 patch antenna elements (not all shown visible in FIG. 3 ). The IPAA 314 is provided from a plurality of subassemblies mechanically coupled together, with eight subassemblies 314 a - 314 h shown in this example. Each of the subassemblies 314 a - 314 h includes a corresponding one of a plurality of active panels 318 a - 318 h and a corresponding one of a plurality of cold plates 342 a - 342 h (cold plates 342 e - 342 g are not shown). The cold plates 342 a - 342 h cool corresponding ones of the active panels 318 a - 318 h . The cold plates 342 a - 342 h may be air cooled, liquid cooled, or both. Each of active panels 318 a - 318 h is electrically coupled to the antenna panel 312 via a first surface thereof. A second surface (not visible) of active panels 318 a - 318 h have active circuits (not visible in FIG. 3 ) disposed thereon. In one embodiment, the AESA 310 comprises eight subassemblies 314 a - 314 h in one 0.5 m×0.5 m assembly (i.e., L=0.5 m and W=0.5 m in FIG. 3 ). In other embodiments, fewer or more than eight subassemblies 314 a - 314 h may be used to provide an AESA having dimensions of 0.5 m×0.5 m. Also, the AESA may be provided having sizes other than 0.5 m×0.5 m. One of ordinary skill in the art will appreciate how to select the number of subassemblies to include in an AESA as well as the length, L, and width, W, required for a particular application. Since the subassemblies 314 a - 314 h are independent, they are sometimes referred to as line replaceable units (LRUs) which indicates that if one of subassemblies 314 a - 314 h were to fail or begin to operate incorrectly or with degraded performance, the subassembly could be removed and a new subassembly could be inserted in its place. Some or all of the outputs from the individual subassemblies 314 a - 314 h may be provided to an input of an SDP which may be the same as or similar to SDPs 210 a - 210 d described above in conjunction with FIG. 2 . The various SDP outputs may also be aggregated. By appropriate selection of the active components coupled thereto, the active panels 318 a - 318 h may be configured to provide a wide range of RF power levels and radar waveforms including short and long transmit pulses at multiple pulse repetition frequencies (PRFs). Different power levels are achieved by appropriate selection of the active components provided as part of the active panels 318 a - 318 h . In some examples, monolithic microwave integrated circuit (MMIC) technologies are preferred and can be used to provide systems which operate with relatively low power T/R channels (e.g., less that about 1 watt (W) per T/R channel). Also, MMIC may be implemented using flip-chip attached circuits in the active panels 318 a - 318 h to provide low power per T/R Channels. Also, flip-chip attached SiGe or RF (radio frequency) CMOS (complementary metal oxide semiconductor) circuits may be used in the active panels 318 a - 318 h to achieve medium power channels (e.g., in the range of about 1 W to about 10 W per T/R transmit channel). Also, flip-chip circuits may be used in the active panels 318 a - 318 h to provide high power channels. It should thus be appreciated that one panel architecture can handle T/R channel RF output peak power from milli-watts (mW) to tens of watts and average power from mW to watts. Thus, by populating the active panels 318 a - 318 h with different types of active circuits (e.g., different types of ICs), the active panels 318 a - 318 h may be appropriate for use in different types of radar or other RF systems. The IPAA 314 described herein efficiently transfers heat (i.e., thermal energy) from an active panel 318 to a corresponding cold plate 342 . Mounting the cold plate 342 directly to the active circuits (not shown) would reduce the number of thermal interfaces between the active circuits and the cold plate. However, due to the varying thickness of the active circuits and bows in the active panel 318 for which the active circuits are attached as well as bows in the cold plate 342 itself, interfacing each and every active circuit is difficult. Therefore, an IPAA 314 that mitigates these variances and provides a thermal interface between the active circuits and the cold plate 342 allows for an efficient transfer of dissipated thermal energy from the active circuits. As will be described further, a thermal conductive material connecting the active circuits with the cold plate 342 allows for efficient transfer of heat from the active circuits. FIG. 4 shows an illustrative computer or other processing device 400 that can perform at least part of the processing described herein. The computer 400 includes a processor 402 , a volatile memory 404 , a non-volatile memory 406 (e.g., hard disk), an output device 408 and a graphical user interface (GUI) 410 (e.g., a mouse, a keyboard, a display, for example), each of which is coupled together by a bus 418 . The non-volatile memory 406 stores computer instructions 412 , an operating system 414 , and data 416 . In one example, the computer instructions 412 are executed by the processor 402 out of volatile memory 404 . In one embodiment, an article 420 comprises non-transitory computer-readable instructions. Processing may be implemented in hardware, software, or a combination of the two. In embodiments, processing is provided by computer programs executing on programmable computers/machines that each includes a processor, a storage medium or other article of manufacture that is readable by the processor (including volatile and non-volatile memory and/or storage elements), at least one input device, and one or more output devices. Program code may be applied to data entered using an input device to perform processing and to generate output information. The system can perform processing, at least in part, via a computer program product, (e.g., in a machine-readable storage device), for execution by, or to control the operation of, data processing apparatus (e.g., a programmable processor, a computer, or multiple computers). Each such program may be implemented in a high level procedural or object-oriented programming language to communicate with a computer system. However, the programs may be implemented in assembly or machine language. The language may be a compiled or an interpreted language and it may be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program may be deployed to be executed on one computer or on multiple computers at one site or distributed across multiple sites and interconnected by a communication network. A computer program may be stored on a storage medium or device (e.g., CD-ROM, hard disk, or magnetic diskette) that is readable by a general or special purpose programmable computer for configuring and operating the computer when the storage medium or device is read by the computer. Processing may also be implemented as a machine-readable storage medium, configured with a computer program, where upon execution, instructions in the computer program cause the computer to operate. Processing may be performed by one or more programmable processors executing one or more computer programs to perform the functions of the system. All or part of the system may be implemented as special purpose logic circuitry (e.g., an FPGA (field programmable gate array) and/or an ASIC (application-specific integrated circuit)). All references cited herein are hereby incorporated herein by reference in their entirety. A non-transitory machine-readable medium may include but is not limited to a hard drive, compact disc, flash memory, non-volatile memory, volatile memory, magnetic diskette and so forth but does not include a transitory signal per se. Having described certain embodiments, which serve to illustrate various concepts, structures, and techniques sought to be protected herein, it will be apparent to those of ordinary skill in the art that other embodiments incorporating these concepts, structures, and techniques may be used. Accordingly, it is submitted that that scope of the patent should not be limited to the described embodiments but rather should be limited only by the spirit and scope of the following claims.

A system provides high-throughput radar signal processing without resorting to costly parallel processing tool kits. The system breaks the signal processing chain into a series of independent data processing units (DPUs) that execute independently and in parallel. Queuing theory is used to efficiently distribute processing across multiple processor cores and/or computers. The system scales to an arbitrary number of cores/computers. The independent nature of the DPUs readily allows addition/replacement of new filters into the system.

CROSS-REFERENCE TO RELATED APPLICATIONS Not applicable. STATEMENTS REGARDING FEDERALLY SPONSORED RESEARCH Not applicable. FIELD OF THE INVENTION The present invention relates to energy treatment systems and more particularly to a system for positioning and protecting an electromagnetic energy delivery handpiece adapted for treating a selected area of tissue. BACKGROUND OF THE INVENTION Lasers and other such devices are used in various surgical procedures for therapeutically treating tissue, such as skin tissue. For example, medical lasers are used to treat naturally occurring skin lesions and discolorations including freckles, age spots, birth marks, melanomas, nevi, and lentigines. Lasers are also used to remove other visible skin features such as tattoos and "port wine" stain birth marks which are caused by a plurality of enlarged blood vessels. A patient may choose to have such skin features treated for cosmetic reasons and/or medical necessity. Generally a medical laser for use in treating skin tissue has a handpiece adapted for manipulation by an operator. The handpiece is coupled to a source of laser energy by a cable that can have an optical fiber for carrying the laser energy to the handpiece. The handpiece is guided to a predetermined distance from the treatment area, i.e., skin surface, by a distance gauge or standoff. For example, U.S. Pat. No. 5,217,455 discloses a method for treating skin tissue with laser energy emitted from a medical laser handpiece having a distance gauge that is placed against the skin to focus the laser energy to a chosen treatment area. The distance gauge is a rod-like member extending from a distal end of the handpiece. U.S. Pat. No. 5,454,807 discloses a catheter-type laser energy delivery system for treating tissue. The catheter used with such a system includes a distal tip assembly having a body with an optical fiber disposed therein. An adjustable standoff extends from alongside the body to maintain a proper distance from the end of the optical fiber and the surface of the tissue to be treated. The above-cited references are incorporated by reference herein. To treat a portion of skin, a suitably trained operator positions the handpiece in a desired location with the standoff placed in contact with the skin of a patient. The standoff maintains a predetermined distance between the handpiece and the skin surface. The operator activates the handpiece to energize a desired tissue area. As the laser energy contacts skin tissue, debris in the form of energized skin tissue is projected away from the treatment site. This tissue debris can be propelled to the energy-emitting end of the optical fiber thereby distorting and/or blocking the flow of laser energy to the treatment area. It would be desirable to provide a system for focusing energy to a desired treatment site, while also protecting a energy delivery handpiece from tissue debris emanating from the treatment site. SUMMARY OF THE INVENTION The present invention provides a system for positioning and focusing an electromagnetic energy delivery system, such as a laser energy delivery system, at a selected treatment site. In one embodiment, the system includes an energy transmissive member positioned at a predetermined distance from a distal end of the laser handpiece. The energy transmissive member protects the laser handpiece from tissue eruptions as laser energy is applied to the treatment site. In one embodiment, the energy transmissive member also focuses laser energy upon the treatment site. Although the invention is primarily shown and described in conjunction with a laser system and handpiece for treating skin tissue, it is understood that the invention is applicable in a variety of additional electromagnetic energy delivering surgical instruments and procedures. The system includes an energy transmissive member adapted for placement on or near a selected area of tissue to focus laser energy to a treatment site. In one embodiment, the energy transmissive member is removably and replaceably secured to a spacer member which itself is mountable upon a laser handpiece. This coupling arrangement enables the energy transmissive member to be secured in a predetermined position with respect to the laser handpiece. The advantages of the system include the ability of the energy transmissive member to protect the handpiece from soiling by any tissue eruptions that may occur at the treatment site. Further, the energy transmissive member can be used to focus the laser energy from the handpiece to the treatment site as well. To effect treatment of a selected tissue area, the handpiece is manipulated by an operator to position the handpiece relative to the treatment site. The energy transmissive member is placed in proximity to the treatment site and the handpiece is actuated by the operator to emit laser energy. Laser energy is then focussed, optionally with the aid of the transmissive member, to a desired location at or below a surface of the tissue. The presence of the transmissive member in proximity to the treatment site and spaced apart from the handpiece prevents any tissue debris from contacting the handpiece and blocking or distorting the laser energy emitted from the handpiece. In another embodiment of the invention, a laser positioning system includes a supply of energy transmissive members, each having different thicknesses and shapes. The energy transmissive members can be secured directly to the laser handpiece, or mounted on a spacer member that is affixed to the laser handpiece. A surgeon can select a suitable energy transmissive member that is most effective to focus laser energy at a treatment site at or below a tissue surface of the tissue. BRIEF DESCRIPTION OF THE DRAWINGS The invention may be more fully understood from the following description of the drawings in which: FIG. 1 is a schematic view of the laser positioning system according to the present invention; FIG. 2 is a perspective view of a portion of the laser positioning system shown in FIG. 1; FIG. 3 is a perspective view of a portion of the laser positioning system of FIG. 1; FIG. 4 is a top view, in partial cross-section along lines 4--4, of a portion of the laser positioning system of FIG. 2; FIG. 5 is a cross-sectional view of the laser positioning system of FIG. 4 along lines 5--5; FIG. 6A is a front view of an exemplary embodiment of a spacer member forming a portion of a laser positioning system according to the present invention; and FIG. 6B is a front view of an alternate embodiment of the spacer member of FIG. 6A. DETAILED DESCRIPTION OF THE INVENTION FIGS. 1-2 illustrate an exemplary electromagnetic energy delivery positioning system, such as a laser positioning system 10, in accordance with the present invention. The system 10 includes an electromagnetic energy source 11, such as a source of laser energy. An optical fiber system 15 conveys the energy from source 11 to a handpiece 12 which can be manipulated by a surgeon. A distal end 13 of optical fiber may extend from a distal end 19 of handpiece 12. The system further includes a spacer member 14 having a proximal end 18 that is mountable upon the handpiece 12 and a distal end 20. The distal end 20 of spacer member 14 is constructed, as described below, so as to be able to selectively engage an energy transmissive member 16 that is removably and replaceably mounted thereon. With the aid of the spacer member 14, the energy transmissive member 16 can be positioned on or near a treatment site and separated from the handpiece 12 by a predetermined distance. The energy transmissive member 16 is effective to protect the distal end of the handpiece 12, including the optical fiber 13 and any lens (not shown) coupled therewith, from tissue debris that may erupt from the treatment site 25 as laser energy contacts the tissue. Optionally, the energy transmissive member 16 can also be used to focus laser energy at the treatment site 15. The laser positioning system 10 is useful in conjunction with a variety of medical lasers for treating selected areas of skin tissue to treat a variety of dermatological conditions, including the removal of freckles, age spots, birth marks, lesions, tattoos, hair and varicose veins. The type of laser energy to be applied to the target tissue is selected based on the properties of a particular type of laser energy in conjunction with the characteristics of the tissue to be treated. Exemplary useful lasers include diode, Alexandrite, ruby, pulsed dye, and gas ion lasers. The applied laser energy is defined by various characteristics including wavelength, pulse duration, fluence, spot size, and peak and average power. The laser energy characteristics are selected in accordance with the intended application and the particular needs of a given patient. The wavelength of the laser energy can range up to about 810 nanometers and is typically applied in pulses as known to one of ordinary skill in the art. The spacer member 14 can have a variety of configurations that securely position the energy transmissive member 16 at a desired distance from the laser handpiece 12. The spacer member 14 should be of sufficient rigidity to resist pressure applied to the handpiece 12 by an operator, and it should not significantly obstruct the operator's view. In one embodiment, the spacer member 14 includes a proximal end 18 that mounts upon the handpiece 12 and a distal end 20 for receiving and holding an energy transmissive member 16. One or more elongate members 22 can extend between the proximal and distal ends 18,20 of the spacer member 14. The elongate member 22 can vary in length to achieve a desired distance between the distal end of the optical fiber 13 and the energy transmissive member 16. One of ordinary skill in the art can readily determine a suitable length for the elongate member 22. In an exemplary embodiment, the length of the elongate member can range from about 5 to 15 mm. The elongate member 22 can be of a predetermined length, or it can have an adjustable length. Where the elongate member 22 does not have an adjustable length, a plurality of elongate members 22, each with different lengths, may be provided as part of a system. An elongate member of a desired length can be selected as appropriate for a given procedure. FIGS. 6A and 6B show exemplary adjustable length spacer members. In FIG. 6A, the elongate member 22' of the spacer member 14' includes a series of sections 23 arranged in a telescoping configuration. The distal end 20' of the spacer member 14' can be extended and retracted with respect to the proximal end 18' to provide a selected length for the elongate member 22'. In FIG. 6B, the distal end 20" of the spacer member 14" is slidable along the elongate member 22". The distal end 20" is secured in position by means of a set screw 25 that impinges upon the elongate member 22". The elongate member 22" can also include a series of spaced markings 27 that indicate the position of the distal end 20" with respect to the elongate member. The proximal end 18 of the spacer member 14 can be adapted for permanent or removable engagement to the handpiece. Removable engagement mechanisms include a ring, mountable upon the handpiece and having a threaded inner portion for engagement with complementary threads on the handpiece. Other removable engagement mechanisms may also be used to attach proximal end 18 to hand piece 12, including detent mechanisms and other positive and/or negative surface features. The proximal end 18 may be permanently attached to the handpiece by a variety of techniques including adhesive bonding and welding. In one embodiment shown in FIG. 3, the proximal end 18 of the spacer member 14 includes a ring 28 coupled to a first end 24 of the elongate member 22. The ring 28 includes a threaded inner surface 29 for removable engagement with complementary threads (not shown) disposed on the handpiece 12. The distal end 20 of the spacer member 14 is secured to or is integral with a second end 26 of the elongate member 22. The distal end 20 is adapted to receive and secure at least one energy transmissive member 16. The distal end 20 of the spacer member 14 can be formed in a variety of configurations such that the energy transmissive member 16 remains in a fixed position and resists displacement in the presence of downward pressure applied to the handpiece 12 by the operator. The distal end 20 can be adapted for permanent or removable insertion of an energy transmissive member. The distal end 20 of the spacer member 14 can include one or more positive and/or negative surface features for engaging complementary surface features of the energy transmissive member 16. Such surface features can provide an interference or snap-fit engagement between the transmissive member 16 and the distal end 20. Alternatively, threads can be formed on an outer surface of an energy transmissive member 16 to engage complementary threads on the distal end 20 of the spacer member 14. FIGS. 4-5 show exemplary embodiments of the distal end 20 of the spacer member 14 having an energy transmissive member 16 secured thereto. The distal end 20 of the spacer member 14 includes an annular member 30 extending from the second end 26 of the elongate member 22. The annular member 30 has an inner surface with a boss 32 disposed thereon. The boss 32 is adapted for engagement within a negative surface feature 34, in the form of a groove, that is formed about the circumference of the energy transmissive member 16. The groove 34 can have a beveled portion 36 to facilitate the insertion of the energy transmissive member 16 within the annular member 30. It is understood other embodiments to secure the energy transmissive member to the spacer member will be readily apparent to one of ordinary skill in the art. One of ordinary skill in the art will readily appreciate that the overall shape and dimensions of the energy transmissive member 16 can vary. The energy transmissive member 16 can be cylindrical, square, triangular, and multi-sided. Similarly, the thickness of the energy transmissive member can be relatively constant or can vary in a manner similar to that of an optical lens. That is, the energy transmissive member 16 can be bi-convex, plano-convex, convexo-concave, bi-concave, plano-concave, and concavo-convex. In one embodiment, the energy transmissive member 16 is cylindrical, i.e., lens-shaped, with a slightly convex entry surface 38 and a slightly concave exit surface 40. The entry surface 38 is curved to reduce the amount of energy that is reflected directly back to the distal end of the optical fiber 13 (FIG. 1). The exit surface 40 is sufficiently concave to focus the laser energy to a predetermined distance from the energy transmissive member 16. It is understood, however, that the energy transmissive member 16 can be shaped such that the laser energy does not converge, or such that it diverges slightly. As noted above, the dimensions of the energy transmission member will vary depending upon the requirements of a given application. One of ordinary skill in the art will readily appreciate suitable dimensions. In an exemplary embodiment, however, the thickness of the energy transmissive member 16 can vary from about one millimeter to about ten millimeters. Further, the cross-sectional area of the entry surface 38 can range from about 0.01 square centimeter to about 5.00 square centimeters. It is understood that a laser positioning system may include a selection of energy transmissive members, each with different shapes, dimensions and optical properties. Once a selected treatment area is identified, an operator selects a particular energy transmissive member 16 having appropriate thickness and, optionally, focusing properties. The operator then determines a desired distance between the optical fiber 13 and the energy transmissive member 16 and selects a spacer member 14 with a suitable length or adjusts the elongate member 22 to a desired length. The appropriate energy transmissive member 16 is then secured to the coupling mechanism 20 such that the energy transmissive member is fixedly positioned with respect to the optical fiber 13 and the handpiece 12. Once the system is assembled, the operator can manipulate the handpiece 12 such that the energy transmissive member 16 rests on the surface of the tissue. The operator then actuates the system to apply laser energy to the treatment site 25 in accordance with predetermined exposure criteria. The laser energy is then focused to a location at or below the surface of the treatment site, with or without the aid of the energy transmissive member 16. The distance below the skin surface to which the laser energy is focused can vary from about zero to about five millimeters. The positional relationship of the energy transmissive member 16 and the surface of tissue, i.e., the epidermal layer, remains substantially constant even as the operator applies pressure to the handpiece. That is, the tissue-contacting surface of the energy transmissive member 16 can impinge upon the tissue surface, but the depth of target tissue below the tissue surface with respect to the tissue-contacting surface remains constant. Thus, handpiece pressure does not alter the depth below the tissue surface to which the laser energy penetrates tissue. During the course of treating tissue with laser energy, tissue eruptions may occur and tend to splatter the handpiece with tissue debris. Such debris can adhere to and block the distal end of the optical fiber 13, and tend to block or distort laser energy. The energy transmissive member 16 is effective to protect the distal end of the optical fiber 13 and the handpiece 12 from fouling due to such tissue eruptions. The laser positioning system preferably includes a series of energy transmissive members 16, each having different dimensions and optical characteristics. Each of the energy transmissive members 16 are removably and replaceably mountable to the spacer member 14 and can be disposed of after use. Prior to conducting a surgical procedure, an operator selects an energy transmissive member 16 that is appropriate for a particular treatment site and/or tissue depth and secures it in the spacer member 14. Alternatively, a spacer member of a suitable length, with a desired pre-attached energy transmissive member is secured to the handpiece 12. The operator then manipulates the handpiece 12 into position and applies laser energy to a treatment site. The selected energy transmissive member 16 protects the distal end of the optical fiber 13 from tissue debris, that may result from the treatment. Optionally, the energy transmissive member 16 is effective to focus the laser energy upon the treatment site. The components of the laser positioning system are selected from materials suitable for the particular component. For example, the spacer member 14 can be formed from a suitably rigid material including polymers and metals such as stainless steel and aluminum. An exemplary embodiment uses a stainless steel spacer member. The energy transmissive member 16 can be formed from a variety of materials well known to those having ordinary skill in the art, that allow the passage of laser energy. Suitable materials include glass, polymers, sapphire and quartz. Having described the preferred embodiments of the invention, it will now become apparent to one of ordinary skill in the art that other embodiments incorporating their concepts may be used. Therefore, the invention is not be limited to the particular embodiments disclosed herein, but rather only by the spirit and scope of the appended claims. All publications and references cited herein are expressly incorporated herein by reference in their entirety.

A system is provided to position an energy delivery handpiece a desired distance from a treatment site while at the same time protecting the handpiece, and energy transmitting optical fibers, from soiling due to tissue debris. The system includes one or more energy transmissive members that are formed from a material that allows the passage of electromagnetic (e.g., laser) energy therethrough. The energy transmissive members can be removably and replaceably attachable to one end of a spacer member. An opposite end of the spacer member is mountable to the energy delivery handpiece. The energy transmissive member is effective protect the handpiece from tissue eruptions. In one embodiment the energy transmissive member also is effective to focus electromagnetic energy upon the treatment site.

RELATED APPLICATIONS [0001] This application is a continuation-in-part application Ser. No. 09/851,685, filed May 8, 2001 and of Ser. No. 09/653,646, filed Sep. 1, 2000, which is a continuation application of Ser. No. 09/226,322, filed Jan. 6, 1999, now U.S. Pat. No. 6,190,018, issued Feb. 20, 2001. BACKGROUND OF INVENTION [0002] 1. Field of Invention [0003] This invention is directed generally to flashlights, and more particularly to a miniature flashlight using a light emitting diode (“LED”) as a light source that is useful for law enforcement personnel and civilians alike. [0004] 2. Background of the Invention [0005] Conventional general purpose flashlights are well known in the prior art and have often been used by law enforcement personnel in the execution of their duties and by them and civilians in emergency situations. Flashlights are used for a wide variety of purposes. For example, they are often used during traffic stops to illuminate the interior of a stopped vehicle or to complete a police report in the dark. They are also used to facilitate searches of poorly lit areas and may be used to illuminate dark alleys or stairwells. Also, they are used to check or adjust equipment when positioned in a darkened area or at night time, and can be used to send coded signals to one another. Generally, small incandescent lightbulbs and LED flashlights were not dependable when needed. [0006] However, the size and weight of conventional flashlights add to the inconvenience and reduce the mobility of law enforcement personnel required to carry such flashlights along with the other law enforcement equipment. Sometimes the flashlight is purposefully or inadvertently left behind. This presents a problem when the need for a flashlight arises and the flashlight is not located on the person, or otherwise readily available In addition to the use of flashlights by law enforcement personnel, civilians also use flashlights for a number of different reasons. Besides the traditional, home uses of flashlights, smaller flashlights are used in today's society for various security purposes. For example, when going to one's car late in the evening, it is not uncommon for an individual, especially a female, to carry a small flashlight with her. She can use the flashlight to assist in getting the key in the keyhole in the dark. Additionally, she can use the flashlight to check whether someone is hiding in the back seat before getting into the car. Even small conventional flashlights, however, are generally cumbersome and inconvenient to carry for this purpose. [0007] Thus, there is a need for a compact, lightweight flashlight that may easily be carried on the person of a law enforcement officer or civilian and conveniently attached to one's keychain or carried on one's clothing to help insure that the flashlight remains in possession of the user and can be quickly and easily retrieved and removed when needed. Description of the Prior Art [0008] Although not having been proven useful to law enforcement personnel, there exists in the prior art a small flashlight known as the Photon Micro Light. The Micro Light consists of two flat, circular 3 volt batteries, a light emitting diode (“LED”) and an outer shell that encloses the batteries and leads of the LED. The Micro Light uses a slide switch or pressure switch that activates the light by moving the leads of the LED into direct engagement with the batteries. The outer shell consists of two hard plastic parts opposite either side of the batteries and may be held together with four threaded screws. [0009] The Micro Light, however, has a number of disadvantages. The Micro Light lacks the durability required for a miniature flashlight. It lacks an internal structure for protecting and securing the batteries and LED. Only the hard plastic outer shell protects the internal components of the flashlight. Thus, little protection is provided for the internal components of the flashlight and the Micro Light may be adversely affected when subjected to shock. [0010] The Micro Light operates by using either a slide switch or pressure switch which upon activation brings both the leads of the LED into direct engagement with the batteries. This results in increased fatigue on the leads of the flashlight and undesirable wear that affects the reliability of the switch. Moreover, because of its external shape and hard plastic outer shell construction, the Micro Light is not suitable for receiving markings or engravings on the outside surfaces thereof, cannot have a medallion installed thereon, have a die struck panel, or disclose using a translucent housing. In many instances it is desirable to color code the exterior of the flashlight, or to provide medallions, die struck panels, engravings, markings, or other indicia on the exterior surface. However, the construction of the Micro Light is not well suited or adapted to allow for any such color coding or desired markings or engravings. SUMMARY OF THE INVENTION [0011] The subject invention is specifically directed to a small, compact LED flashlight useful to both law enforcement personnel and civilians. One embodiment of the invention may include an LED flashlight wherein the LED has first and second leads extending therefrom; a power source; a power source frame enclosing at least a portion of the power source; a power source frame housing containing the power source frame, light source and power source; a switch located adjacent the power source and operable to close a circuit including the light source and the power source; a keyring extension extending from the power source frame, said keyring extension having an opening whereby an article can be attached to the keyring extension, and the keyring extension further includes a keyring lock connected to the power source frame or power source frame housing wherein upon exerting a force against the keyring lock, the keyring lock is opened to permit the article to be attached to the keyring extension. [0012] The power source frame is non-conductive and has a cavity adapted to house the power source. The power source frame may also have a receptacle for receiving and housing a connector end of the light source. The power source frame therefore serves as a fitted compartment for holding in place and protecting the various internal components of the flashlight. The power source frame provides significant protection to the power source and the light source and serves to cushion these elements from the adverse affects of any shock the flashlight might receive. The power source frame housing encases the power source frame, and provides further protection to the internal components of the flashlight, in addition to that provided by the power source frame. The power source frame housing thus serves to provide an additional level of protection to the light source and the power source and enhances the durability of the flashlight. [0013] Another embodiment of the invention may include an LED flashlight wherein the LED has first and second leads extending therefrom; a power source having a first side and a second side, the second side being opposite the first side; a housing enclosing the leads of the LED and the power source, wherein the housing is comprised of translucent material; and a switch operable to close a circuit including the LED and the power source. [0014] Still a further embodiment of the invention may include an LED flashlight wherein the LED has first and second leads extending therefrom; a power source; a housing containing the LED and the power source; the housing includes at least one side cover which is not integral with the housing; the at least one side cover being selected from anodized metal, anodized metal which includes indicia, die struck metal, laser engraved metal, and a side cover having a separate medallion attached thereto; and a switch located adjacent the power source and operable to close a circuit including the light source and the power source. [0015] The LED is preferably an LED that has a high luminous intensity. Manufacturers of LEDs grade the LED according to its quality. The highest quality LEDs are given an “E” grade. The next highest quality is a “D” grade. LEDs with a “D” grade can be equipped with a lens to approximate the quality of an “E” grade LED. LEDs of this quality were initially used in medical applications and are sometimes referred to as having medical grade application. Although the flashlight of the present invention can be used with any conventional LED, in a preferred embodiment, the light source is an “E” grade LED or lensed “D” grade LED. Such a high intensity LED may be obtained from Hiyoshi Electric, Co., Ltd. located in Tokyo, Japan, having Part No. E1L533BL. The high intensity LED herein described has from three to five times the luminous intensity of a conventional LED. The LED preferably emits blue light, although the present invention may be used with any color LED. Blue light helps to preserve a user's night vision compared with conventional flashlights emitting white light. For other applications bluegreen LEDs can be used, for example, in situations where compatibility with night vision equipment is desired. Other colored LEDs can also be used. Red LEDs can be used in applications where the preservation of night vision is desired or for use with pilots and photographers, and even infrared LEDs can be used where certain signalling capabilities are required or for use with equipment that senses infrared light. The LED includes first and second leads extending from a connector end of the LED. The LED leads may be provided with extensions that can be soldered onto the leads of the LED. [0016] The power source may be any battery having sufficient power to energize an LED. The power source is preferably round and has oppositely disposed generally flat sides, sometimes referred to as coin cells. A pair of stacked 3 volt batteries of this type may be used as the power source. Three-volt lithium batteries are preferably used to provide for longer life, and greater shelf life. [0017] The power source frame may be made of nonconductive plastic and preferably has generally flat oppositely disposed first and second sides. The power source frame may be adapted to receive and house a power source, and includes a power source cavity for this purpose. The power source frame also includes a receptacle at a front end to receive and house a connector end of an LED. The leads of the LED are preferably positioned so that one lead extends over the first side of the power source and another lead extends over the second side of the power source. The power source frame protects and secures the internal components of the flashlight. The power source frame also provides resistance to shock and safeguards the light source and power, source within its frame. The power source frame may include a power source cavity cover that serves to further enclose the power source, and may include a bottom support beneath the cavity for further supporting the power source. [0018] A switch element is preferably located on the side opposite of the power source cavity. The side of the power frame opposite the side having the power source cavity may include a counterbore having a terminus in the power source frame that houses a switch element. The counterbore may be included in the power source cavity cover as well. The switch element is preferably a dome plate that is located between one of the leads of the LED and the power source, but out of contact with the power source. The dome plate is sometimes referred to as a tactile dome plate or a snap dome plate. The switch is activated by applying pressure to the dome plate, thereby completing a circuit that includes the leads of the LED and the power source. With this switch arrangement, a switch button is depressed forcing one lead of the LED into contact with the dome plate which in turn contacts the power source. Thus, in this embodiment, one lead of the LED never comes into direct contact with the power source. Once pressure is removed from the button, the contact between the dome plate and power source is broken and the flashlight returns to its normal “off” position. Thus, the switching arrangement reduces the wear on the leads of the LED and increases the overall reliability. [0019] The power source frame may be adapted to receive a weight, which is preferably round and has opposite ends coplanar with the opposite sides of the power source frame. The weight may be press fit into a cavity or tapered hole in the power source frame specifically adapted to receive the weight. The weight provides for a heavier flashlight and improved balance. In addition, the weight provides the flashlight with greater substance and as a result a higher perceived value in the hands of the user. With the additional weight added to the flashlight, the flashlight appears more substantial and of a higher quality than a lighter weight flashlight. [0020] The power source frame housing is preferably of a two piece construction, with each piece disposed on either side of the power source frame. The power source frame housing includes a first housing side disposed about the first side of the power source frame and a second housing side disposed about the second side of the power source frame, the two sides conforming to the periphery of the power source frame. The housing is preferably constructed of plastic. In one embodiment, the housing may be translucent. In this manner, the light from the LED may be dispersed throughout the housing to effectively illuminate the light. In one embodiment, the entire housing may be translucent. It may also be colored to match the color of the LED. For example, a red translucent housing may be used with a red LED, a blue translucent housing may be used with a blue LED, etc. [0021] The power source frame may have a plurality of pegholes located about the periphery of either side thereof. In addition, the first and second housing sides of the power source frame housing may be provided with a plurality of pegs extending from an inner periphery thereof. The pegs are positioned to engage in a mating relationship with the plurality of pegholes located about the periphery of the sides of the power source frame such that the housing sides can be engaged with the power source frame. The mating of the pegs and the pegholes facilitates assembly of the flashlight by allowing the parts to be precisely aligned during their assembly. It has been found that gluing the power source frame housing to the power source frame provides for a suitable adhesion of the parts. Alternately, ultrasonic welding can be used to attach the parts. Unlike the prior art, separate screws are not needed to attach the parts of the flashlight together and thus assembly is facilitated. In this manner, the housing sides may include notches that mate with corresponding notch receptacles on the power source frame. The housing sides may thus be advantageously ultrasonically welded to the power source frame. [0022] The flashlight housing may be provided with at least one separate side cover and preferably be provided with first and second side covers that are positioned between the first and second housing sides of the power source frame housing and with the housing sides sandwiches the power source frame. The side covers preferably lie in parallel planes and may have flat outer surfaces that are capable of receiving engravings or markings. It is often desirable to engrave or imprint the side covers with surface indicia. For example, a company logo or name of a product could be located on either of the side covers. The use of engraving or printing on the side covers can be used for promotional or advertising purposes. In addition, a flashlight bearing certain markings on the side covers could serve as a prize or be used to commemorate an important event. In one embodiment, a die struck medallion could be inset in the side cover. [0023] The side covers can be made of a variety of materials, such as metal, plastic, or other protective materials. The side covers are preferably made of anodized aluminum. Aluminum provides the desired strength to the side covers and is easily anodized aluminum engraved or imprinted. Indicia may be laser engraved, silk screened, inked, pad printed, or marked in any known manner. In the embodiment where the housing is translucent, the side covers may also be made of a translucent plastic material, or they may be made of non-translucent plastic or metal. Thus, a flashlight may be provided with a translucent housing, and translucent side covers, or a translucent housing and opaque side covers. Where both the housing and side covers are translucent, they may of different colors, to present a two, or even three, tone flashlight. Further, the flashlight may include a translucent power source frame as well. Where translucent side covers are used, indicia may be engraved or printed on the inside surface of the side cover. Thus, the side cover protects the indicia from being marred by normal wear and tear, and also by virtue of being translucent, may provide an attractive gloss finish highlighting the indicia. [0024] In another embodiment, the side covers are a die struck, or coined metal, preferably brass, in which physical indicia may be formed in the metal side cover. Most preferably, both sides of a side cover are struck to provide finer detail in the physical indicia, which may include a company logo, name, or other suitable information. [0025] In another embodiment, a side cover can have a medallion therein. One way of doing this is to cut a hole the size of the medallion in the side cover. An appropriate support and single faced adhesive is attached to the inside of the side cover so that the adhesive can be used to attach the medallion too the side cover. [0026] The side covers provide additional protection to the internal components of the flashlight. The sturdy aluminum construction serves to guard the light source and power source from external forces. Moreover, there is an insulated pocket located between the power source frame and the side covers that provides an air cushion that serves to further protect the light source and power source within the power source frame housing. The side covers may be manufactured as separate components of the flashlight from the power source frame housing. Thus, side covers of varying colors may used to assemble flashlights of varying and contrasting colors. For example, flashlights having side covers bearing corporate colors can be easily assembled. Similarly, flashlights having side covers bearing the colors of a favorite team can be provided. For example, a flashlight having a green side cover on one side and a yellow side cover on the other side could be used to represent the colors of the Green Bay Packers. In addition, a Green Bay Packers logo could be included on one or both side covers of the flashlight. [0027] One of the side covers is adapted to receive a switch button that is secured to the side cover. The button may be made of rubber, and is preferably made of Kraton, the trade name of a thermoplastic rubber made by the Shell Oil Company, and located adjacent the power source. When the button is pushed, a circuit including the leads of the LED and the power source is completed. [0028] The power source frame or power source frame housing may be provided with a keyring extension. The keyring extension may directly extend from the housing or power source frame. The keyring extension includes a keyring lock that opens and closes the keyring extension when a force is exerted against the keyring lock. The keyring extension is opened to permit an item such as a keyring to be attached to the keyring extension. The keyring lock is preferably springbiased and may be attached to the power source frame. The keyring lock may pivot about a circular post positioned on the power source frame. Alternatively, the keyring lock may extend from the interior of the housing, or if a power source frame is used, extend from the power source frame. The keyring extension may be easily attached and detached from any number of items, such as the zipper of a coat or backpack, the handle of a purse or briefcase, a beltloop, or any other handle or case. [0029] The flashlight of the present invention is small, compact and easy to operate. The flashlight may easily be carried in the pocket, on the clothing, or on the keychain of law enforcement personnel or civilians. The flashlight may also be quickly and easily retrieved and operated. [0030] In another embodiment of the invention, a magnet may be provided on the flashlight. It may be internal, external, or coextensive with the housing sides or side covers. Preferably, the magnet is internally positioned within the flashlight. It may be positioned within the interior of the housing, or if a power source frame is used may be positioned on the power source frame or within a cavity on the power source frame. An internal magnet allows for indicia to be marked, printed, or engraved on the housing or side covers of the flashlight. When internally positioned, the magnet is protected from chipping or scratching that could occur if the magnet were externally mounted to the flashlight. Moreover, the magnet itself does not scratch the surface to which it may be mounted as the magnet is protected by the housing or side covers. The magnet may be of sufficient strength to allow the flashlight to be mounted to metal objects. In a preferred embodiment using a magnet, the magnet is of sufficient strength to allow the magnet to attach to metal objects even when using side covers that are made of aluminum or other metals. [0031] It will be understood by those of skill in the art that the various aspects of the disclosed embodiments may be used alone or in connection with the other aspects of the disclosed embodiments. For example, the various disclosed keyring extensions may be used with a housing, with a power source frame and power source frame housing together, with or without side covers, with a translucent housing, with a magnet, etc. BRIEF DESCRIPTION OF THE DRAWINGS [0032] Further advantages of the present invention will become apparent to those skilled in the art with the benefit of the following detailed description of the preferred embodiments and upon reference to the accompanying drawings in which: [0033] [0033]FIG. 1 is a perspective view of an embodiment of the flashlight of the present invention. [0034] [0034]FIG. 2 is a side view of the flashlight depicted in FIG. 1. [0035] [0035]FIG. 3 is a side view of a first side of the power source frame. [0036] [0036]FIG. 4 is a side view of a second side of the power source frame opposite the first side. [0037] [0037]FIG. 5 is a side view of a power source consisting of two circular batteries having generally flat sides. [0038] [0038]FIG. 6 is a side view of alight emitting diode (LED). [0039] [0039]FIG. 7 is a perspective view of a weight. [0040] [0040]FIG. 8 is a side view of a first side of the power source frame including a power source, an LED, a keyring lock, and a spring. [0041] [0041]FIG. 9 is a side view of a second side of the power source frame including an LED, a weight, a keyring lock, a spring, and a switch element. [0042] [0042]FIG. 10 is a cross-sectional view of the power source frame of FIG. 4 taken along plane 11 . [0043] [0043]FIG. 11 is a side view of the exterior of a first side of the power source frame housing. [0044] [0044]FIG. 12 is a side view of the interior of a first side of the power source frame housing. [0045] [0045]FIG. 13 is a side view of the exterior of a second side of the power source frame housing. [0046] [0046]FIG. 14 is a side view of the interior of a second side of the power source frame housing. [0047] [0047]FIG. 15 is a side view of a first side cover. [0048] [0048]FIG. 16 is a side view of a second side cover. [0049] [0049]FIG. 17 is a cross-sectional view of a switch button. [0050] [0050]FIG. 18 is a partial cross-sectional view of the flashlight of FIG. 2 taken along the plane 22 . [0051] [0051]FIG. 19 is a side view of an alternate embodiment of the power source frame. [0052] [0052]FIG. 20 is the opposite side view of the power source frame shown in FIG. 19. [0053] [0053]FIG. 21 is a side view of a power source cavity cover. [0054] [0054]FIG. 22 is an opposite side view of the power source cavity cover shown in FIG. 21. [0055] [0055]FIG. 23 is a perspective view showing the power source cavity cover of FIGS. 21 and 22 used in connection with the power source frame of FIGS. 19 and 20. [0056] [0056]FIG. 24 is atop view of an alternate embodiment of a keyring extension and keyring lock in a connecting relationship. [0057] [0057]FIG. 25 is a top view of the keyring lock of FIG. 24. [0058] [0058]FIG. 26 a is a top view of another alternate embodiment of a keyring lock showing a latch receptacle in dotted lines. [0059] [0059]FIG. 26 b is a bottom view of the keyring lock of FIG. 26 a. [0060] [0060]FIG. 27 is a side view of an alternate embodiment of a power source frame having a cavity for a magnet. [0061] [0061]FIG. 28 is an opposite view of the power source frame of FIG. 27. [0062] [0062]FIG. 29 is a view of the power source frame of FIG. 28 along line 2929 showing a magnet and magnet cavity in dotted lines. [0063] [0063]FIG. 30 is side view of an alternate embodiment of the present invention showing a flashlight with a translucent housing. [0064] [0064]FIG. 31 is an opposite side view of the flashlight of FIG. 30. [0065] [0065]FIG. 32 is a side view of a flashlight having an alternate embodiment of a keyring lock. [0066] [0066]FIG. 33 is a side view of the inside of a die struck cover according to the present invention. [0067] [0067]FIG. 34 is a side view of the outside of the die struck panel of FIG. 33. [0068] [0068]FIG. 35 is a front side view of a cover having a medallion pocket. [0069] [0069]FIG. 36 is FIG. 35 with the medallion in the pocket. [0070] While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawings and detailed description thereof are not intended to limit the invention to the particular form disclosed, but on the contrary, the invention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0071] A handheld flashlight 10 made in accordance with the principles of the subject invention is depicted in FIGS. 118. As shown in FIG. 2, flashlight 10 preferably includes a side cover 12 , a power source frame housing 14 , a keyring extension 16 , a keyring lock 80 , a switch button 18 , and a light source 20 , extending from a front end of the flashlight. [0072] As depicted in FIGS. 3 and 4, the flashlight of the subject invention further includes a power source frame 22 . The power source frame 22 has oppositely disposed first and second sides 26 , 33 that are generally flat and lie in parallel planes. The power source frame 22 further includes a cavity 24 located on the first side 26 of the power source frame adapted to receive a power source, such as that depicted in FIG. 5. The frame 22 also is provided with a receptacle 28 at a front end 30 thereof, adapted to receive a light source, such as that depicted in FIG. 6. The first side 26 further includes a light source lead channel 29 extending from receptacle 28 to cavity 24 to allow a lead from the light source 20 to extend over cavity 24 . [0073] As depicted in FIG. 3, the power source frame 22 may also include an area 32 adapted to receive a weight. In the embodiment shown in the figures, although not required, the area 32 is a throughhole extending from the first side 22 of the frame to the second side 33 of the frame. Area 32 is tapered at a slight angle to allow the weight to be friction fit within area 32 . The power source frame 22 is further provided with a plurality of pegholes 100 positioned about an outer periphery of the first side 26 of the power source frame. The pegholes 100 are adapted to receive a corresponding set of pegs located on the power source frame housing 14 . The mating of the pegs with the pegholes positions the power source frame housing 14 in proper alignment with the power source frame 22 . The power source frame housing may be ultrasonically welded to the power source frame and/or glued thereto. Thus, there is no need to use threaded screws or other fastening means to hold the frame and the housing together. As a result, the flashlight of the invention is assembled without difficulty. [0074] The power source frame 22 is preferably made of a nonconductive material. Preferably, the power source frame 22 is comprised of Acrylonitrile Butadiene Styrene “ABS” which provides for exceptional durability and toughness. However, any nonconductive material may be employed to construct the frame 22 . Polycarbonate is preferred where the power source frame is translucent. [0075] [0075]FIG. 4 depicts a side view of the second side 33 of power source frame 22 . The second side 33 is provided with a counterbore 34 having a terminus 36 within the power source frame 22 . As shown in FIG. 4, the counterbore 34 is adapted to receive a switch element. The counterbore 34 is preferably located opposite the power source cavity 24 and includes a throughhole 38 extending into cavity 24 that is located on the first side 26 of the power source frame 22 . [0076] As with the first side 26 , the second side 33 preferably includes a light source lead channel 39 extending from receptacle 28 to counterbore 34 to allow a lead from the light source 20 to extend over counterbore 34 . The second side 33 of power source frame 22 may preferably further include a post 40 about which an element of the keyring lock 80 may pivot. Power source frame 22 is also provided with a hub 42 located on a rear side 44 of the frame 20 that is adapted to secure one end of a spring element associated with the keyring lock 80 . As with the first side, the second side 33 of the power source frame may be provided with a plurality of pegholes 110 positioned about its outer periphery to mate with a corresponding set of pegs located on the power source frame housing 14 . [0077] The power source may be any type of battery with sufficient power to energize the light source. As shown in FIG. 5, the power source is preferably one or more circular batteries 50 having generally flat oppositely disposed first and second sides 52 and 54 . In a preferred embodiment, the power source consists of two 3 volt lithium coin cell batteries available from Panasonic bearing the CR2016 marking. These lithium batteries provide for exceptionally long life and durability. In addition, they operate at a low temperature, are leakproof, and vibration resistant. [0078] The light emitting diode light source may be of any type suitable for flashlight use. As shown in FIG. 6, the light emitting diode (“LED”) 60 has first and second leads 62 and 64 extending therefrom. An LED provides great advantages over conventional neon or incandescent light sources, since it requires much less energy, is smaller in size, and more resistant to shock than conventional light sources. It also generates less heat and is more durable than a conventional light source. LEDs are widely available, inexpensive, and can be replaced easily and quickly. In a preferred embodiment, the light source is a high intensity LED having a high luminous intensity emitting blue light. The LED may be a “E” grade LED or a lensed “D” grade LED. [0079] The flashlight may include a weight 70 positioned in area 32 on the power frame housing 14 . The weight provides for a heavier flashlight and for improved balance. It also provides a more substantial feel to the flashlight resulting in a higher perceived value. In a preferred embodiment shown in FIG. 7, the weight 70 has a cylindrical shape and has oppositely disposed first and second faces that are generally flat and lie in parallel planes. The weight 70 preferably has a thickness equal to the thickness of the power source frame 14 . It is preferably made of a dense metal material, preferably stainless steel, and preferably weighs approximately eleven grams. The weight is friction fit or press fit into the corresponding portion of the power source frame housing. [0080] [0080]FIG. 8 is a side view of the first side 26 of the power source frame 22 and depicts power source 50 , LED 60 , keyring lock 80 , and spring 82 . The power source frame 22 preferably has a thickness in the range of approximately 0.15 and 0.25 inch, and preferably 0.018 inches, which is approximately equal to the diameter of LED 60 . As shown in FIG. 8, the LED 60 is positioned in receptacle 28 of the power source frame 22 , and the power source SO is positioned in the cavity 24 of the power source frame 22 . [0081] A first lead 62 of the LED 60 preferably extends over the first side 52 of the power source 50 , which is preferably coplanar with the first side 26 of the power source frame 22 . A lead extension 75 may be attached to the first lead 62 of the LED to extend the length of the lead. The lead extension 75 may be soldered to the first lead 62 . The weight 70 may be positioned within the power source frame 22 , and preferably has a first side 72 that is coplanar with the first side 26 of the power source frame. The weight 70 is preferably press fit or friction fit within the power source frame 22 . [0082] [0082]FIG. 9 is a side view of the second side 33 of the power source frame 22 and depicts LED 60 , weight 70 , keyring lock 80 , spring 82 and switch element 90 . As shown in FIG. 9, the switch element 90 is positioned in the counterbore 34 . The switch element 90 has an outer periphery that contacts the terminus 36 of the counterbore 34 , but is out of contact with the power source 50 . The second lead 64 of LED 60 preferably extends over the switch element 90 . A lead extension may be attached to the second lead 64 , as required. [0083] The switch element 90 is preferably a dome plate 92 or a convex conductor that is positioned in the counterbore 34 , but out of contact with the power source 50 . The dome plate is preferably made of a thin, flexible conductive metal stamping. The lead 64 of the LED contacts the dome plate. To ensure contact, the lead may be taped to the dome plate using, for example, 1.5 millimeter thick tape manufactured by 3M. The dome plate preferably has an engaging element 91 located at the center of its inner surface. [0084] When pressure is applied to the dome plate, the dome plate flexes from a convex to a concave configuration, thereby completing the circuit through the first and second leads of the LED, the engaging element of the dome plate, and the power source. When the pressure is removed, the dome plate returns to its convex position breaking contact with the power source and returning the flashlight to its normal “off” position. In this manner, the lead does not come into direct contact with the power source. It should be noted that a number of alternative push button switch arrangements could be used. For example, the power source frame could include a flexible tongue adjacent to the power source. A lead of the LED could be wrapped around the tongue such that depression of the tongue would bring the lead of the LED into contact with another switch element or into direct contact with the power source to complete the circuit. Alternatively, the lead of the LED could be connected to a flexible tongue having a split metal eyelet adjacent the power source, such that depression of the tongue would complete the circuit. In addition, a number of other mechanical or electrical switches could be utilized, such as slide switches and pressure switches. [0085] As shown in FIG. 9, the keyring lock 80 includes hub 84 operatively connected to a coil spring 82 which is in turn operatively connected to hub 42 of power source frame 22 . It should be understood that many types of springs can be used to bias the keyring lock including coil springs, leaf springs, and U-shaped or plastic springs to name a few. The coil spring may be a separate component, or may be made integral with the power source frame. Spring 82 exerts a force to bias keyring lock 80 to pivot outwardly and about post 40 . The keyring lock 80 is preferably adapted to pivot about post 40 for only a limited distance. Keyring lock 80 further includes a stop 86 that abuts the power source frame 22 to limit the travel of the keyring lock 80 . Preferably, the stop 86 prevents an outer edge 88 of the keyring lock to travel beyond the position where the edge 88 is parallel to an edge 89 of the power source frame. Other keyring locking mechanisms could be used having other forms of springs or resistance to bias the keyring lock. Alternately, the keyring lock could be externally or internally hinged. [0086] The keyring extension 16 and keyring lock 80 of the present invention provide a user with significant versatility in attaching the flashlight to the user's person. For example, the keyring lock 80 may be moved to its open position to allow the flashlight to be easily attached to the zipper of a coat or backpack, the handle of a purse or briefcase, a beltloop, or any other handle or case. In addition, because the keyring lock 80 is normally biased into its closed position, the keyring extension and keyring lock 80 can serve as a clip to easily fasten the flashlight to a shirt pocket or directly to one's clothing. In this manner the shirt pocket or portion of clothing is pinched between an outer end 134 of keyring lock 80 and an outer end 132 of keyring extension 16 . (See FIG. 2). The ability to easily clip the flashlight to one's clothing provides the user with great flexibility in carrying the flashlight on one's person. [0087] [0087]FIG. 10 is a cross-sectional view of the power source frame 22 of FIG. 4 taken along line 11 . Cavity 24 on side 26 preferably has a depth equal to the thickness of the power source 50 and encloses all but an outer surface of the power source. Counterbore 34 on side 33 is located opposite the cavity 24 and has a terminus 36 in the power source frame and throughhole 38 extending therethrough into cavity 24 . The diameter of the counterbore 34 is preferably slightly larger than throughhole 38 . [0088] FIGS. 3 - 10 depict the inner workings of an embodiment of the present invention. However, the invention is not intended to be limited by the particular geometry, locations, and components depicted herein, which are illustrative. [0089] [0089]FIG. 11 is a side view of the exterior of a first housing side 150 of the power source frame housing 14 depicted in FIG. 1. First housing side 150 is adapted to fit over and enclose the first side 26 of the power source frame 22 . [0090] [0090]FIG. 12 is a side view of the interior 156 of first housing side 150 . A plurality of pegs 158 are preferably positioned about an inner periphery of the first housing side 150 . As mentioned above, the pegs 158 are adapted to engage in a mating relationship a corresponding plurality of pegholes 100 located on an outer periphery of the first side 26 of the power source frame 22 . [0091] [0091]FIG. 13 is a side view of an exterior 142 of a second housing side 140 of power source frame housing 14 depicted in FIG. 2. The second housing side 140 is adapted to fit over and enclose the second side 33 of the power source frame 22 . With reference to FIGS. 2 and 13, the exterior 142 includes a keyring extension 16 extending from a rear side 144 thereof. An outer end 132 of keyring extension 16 engages an outer end 134 of keyring lock 80 (as shown in FIG. 2). Alternatively, the keyring extension could be attached to, or integral with, the power source frame, such that the power source frame housing could fit over and enclose the power source frame, except for the keyring extension. In such an alternate embodiment, the second housing side 140 will be identical to the first housing side 150 , shown in FIG. 12. [0092] [0092]FIG. 14 is a side view of an interior 146 of second housing side 140 . A plurality of pegs 148 are preferably positioned about an inner periphery of second housing side 140 . The pegs 148 are adapted to engage in a mating relationship a corresponding plurality of pegholes 110 located on an outer periphery of the second side 33 of the power source frame 22 . [0093] FIGS. 11 - 14 show first and second power source frame housing sides having an opening therein to accommodate the side covers shown in FIGS. 15 and 16. It should be understood, however, that the power source frame housing sides are not limited to accommodating the particular side covers shown in FIGS. 15 and 16. They could be modified to be used with side covers of any geometry. In addition, the housing sides could be made without any openings and used without side covers, such that the power source frame housing sides would completely enclose the power source frame housing. Also, the power source frame housing can be made from any suitable material, and is preferably strong and durable. In a preferred embodiment, the power source frame housing is made of ABS. [0094] [0094]FIGS. 15 and 16 are side views of first and second side covers 160 and 170 . The first and second side covers are preferably positioned between the power source frame 22 and the power source frame housing 14 . First and second side covers 160 and 170 are generally flat and adapted to conform to the outer surfaces of the power source frame 22 such that the side covers preferably lie in parallel planes when positioned between the power source frame 22 and the power source frame housing 14 . The power source frame housing 14 conceals the edges of the side covers when they are positioned between the power source frame 22 and the power source frame housing 14 . The side covers may be of any suitable material including metals, rubbers, and plastics. Preferably the side covers are made of stamped aluminum, preferably anodized 6061 aluminum, and have surfaces suitable for marking or engraving. As noted above, it is often desirable to engrave or imprint the side covers with surface indicia. For example, a company logo or name of a product could be located on either of the side covers. The use of engraving or printing on the side covers can be used for promotional or advertising purposes. In addition, a flashlight bearing certain markings on the side covers could serve as a prize or be used to commemorate an important event. [0095] [0095]FIGS. 35 and 36 illustrate a die struck medallion 161 inset in one of the side covers 162 . A hole 163 is cut in the side cover 162 the size of the medallion 161 . The medallion is shown as cylindrical, but could be any shape, i.e., box, oval, etc. A piece of adhesive 164 is placed inside of the cover so that an adhesive portion 165 faces the outside of the side cover and forms a medallion pocket that permits the medallion to be attached to the side cover. Other mechanisms can be used to attach the medallion to the side cover such as adhering a support piece within the side cover to form the base of the medallion pocket and using an appropriate adhesive to attach the medallion to the side cover. Also, although the medallion is generally metal, it can be any suitable material, i.e., plastic. [0096] A further embodiment is shown in FIGS. 33 and 34 wherein the side cover 166 is die struck metal, i.e., brass, aluminum, wherein the entire side cover 166 is die struck metal, i.e., brass, aluminum having the desired depiction 167 (positive), 167 a (negative) die struck on both sides 168 and 169 for greater detail. This provides a special flashlight for a designated group of people. [0097] The side covers can be made of a variety of materials, such as metal, plastic, or other protective materials. Generally, the side covers are preferably made of anodized aluminum. Aluminum provides the desired strength to the side covers and is easily engraved or imprinted. Indicia may be laser engraved, silk screened, inked, pad printed, or marked in any known manner. [0098] The side covers are on both sides of the power source frame and are held by the power source frame housing. The side covers provide additional protection to the internal components of the flashlight. The sturdy aluminum construction serves to guard the light source and power source from external forces. Moreover, there is an insulated pocket located between the power source frame and the side covers that provides an air cushion that serves to further protect the light source and power source within the power source frame housing. As noted above, in applications where no side covers are used, it is desirable to similarly provide a spaced pocket of air between the power source and the power source frame housing sides to further protect the light source and power source. [0099] As shown in FIG. 15, the second side cover 170 has a hole 172 therethrough adapted to receive a switch button 18 (shown in FIG. 17). When the side cover 170 is positioned between the power source frame 22 and the power source frame housing 14 , hole 172 is located adjacent the switch element 90 . In a preferred embodiment, a thin piece of foam (not shown) is attached to the inner surface of the first side cover 160 . When the flashlight is assembled, the piece of foam serves to compress the first lead 62 of the light source 20 into engagement with power source 50 . The piece of foam also serves to keep the elements of the power source frame 22 tightly enclosed therein, and prevents the internal components from rattling or making noise when in use. [0100] [0100]FIG. 17 is a side view of switch button 18 . Switch button 18 is preferably circular with a circular recess 182 about its periphery. The recess 182 is adapted to secure the switch button 18 to the second side cover 170 . Switch button 18 is preferably made of a resilient material, such as rubber, to allow the button to deform when a force is exerted thereon. In a preferred embodiment, the switch button 18 is made of Kraton, the trade name of a thermoplastic rubber made by the Shell Oil Company. [0101] The switch button 18 further includes an engaging element 184 on an interior surface thereof. When a force is exerted on the button, the engaging element 184 contacts the switch element 90 located in the power source frame 22 . When not engaged, the engaging element 184 is preferably out of contact with the switch element 90 . [0102] [0102]FIG. 18 is a partial cross-sectional view of the flashlight 10 taken along the line 22 of FIG. 2. As shown in FIG. 18, switch button 18 is secured to second side cover 170 , which is positioned between the second housing side 140 of power source frame housing 14 and the power source frame 22 . The engaging element 184 of switch button 18 is preferably positioned adjacent to, but out of contact with, dome plate 92 . An outer periphery 186 of the interior surface of switch button 18 engages an outer periphery of dome plate 92 . As a force is exerted on switch button 18 , the engaging element 184 contacts dome plate 92 . The dome plate 92 then moves in a direction towards the power source 50 until it comes in contact with power source 50 . Once contact is made, a circuit including the leads of the light source 60 , the dome plate 92 , and the power source 50 is completed. [0103] Typically, a flashlight pressure switch makes noise upon its engagement. With the switch button configuration shown herein, the noise created by the dome plate 92 coming in contact with the power source 50 is muffled because the switch button 18 completely encloses the dome plate 92 in the power source frame. Moreover, a raised annular portion 190 of the power source frame partially encloses the outer diameter of the switch button to further enclose the switch button and muffle any sound from the operation of the dome plate. In addition, 1.5 millimeter thick 3M tape may be placed over the lead and dome plate to further muffle the sound of the switch operation. In addition, a small notch is placed in the outer periphery 186 of the interior surface of switch button to allow air to escape through the notch when the button is depressed. [0104] Thus, any noise created is muffled within the switch button 18 . In addition, with the disclosed switch button configuration, when a force is exerted on the dome plate 92 , the user is able to feel the flexure of the dome plate as it moves into contact with the power source 50 . Thus, the switch button configuration provides tactile feedback to the user so that the user is able to feel when the dome plate has come into contact with the power source, and when it is released. This tactile feedback is particularly useful where the flashlight is being operated out of the direct sight of the user, and it is not possible to tell by sight whether the flashlight is on or off. [0105] FIGS. 19 - 23 depict an alternate embodiment of a miniature LED flashlight. As shown in FIGS. 19 and 20, power source frame 222 has oppositely disposed first and second sides 226 , 233 that are generally flat and lie in parallel planes. The power source frame 222 further includes a cavity 224 located on the second side 233 of the power source frame adapted to receive a power source, such as that depicted in FIG. 5. The frame 222 also is provided with a receptacle 228 at a front end 230 thereof, adapted to receive a light source, such as that depicted in FIG. 6. The first side 226 further includes a light source lead channel 229 extending to cavity 224 from receptacle 228 to allow a lead from the light source 220 to extend into cavity 224 . [0106] As depicted in FIG. 20, the power source frame 222 may also include a cavity 232 adapted to receive a weight. In the embodiment shown in the FIGS. 19 and 20, although not required, the power source cavity 224 and the weight cavity 232 have a bottom support 235 positioned on side 226 of the power source frame 222 . The bottom support 235 may be separate from, but is preferably molded integrally with, the power source frame 222 . In addition, the bottom support 235 is shown supporting both the power source cavity 224 and the weight cavity 232 , but also could be limited to support only one or the other. [0107] As shown in FIGS. 21 and 22, a power source cavity cover 240 may be used in connection with the power source frame 222 shown in FIGS. 19 and 20. Power source cavity cover 240 may include pegs 242 that mate in pegholes 244 located on side 233 of power source frame 222 . While such pegs are preferred for proper alignment of the power source cavity cover, any number of known conventions, such as notches, tabs, etc. could be used to properly position and secure the power source cavity cover to the power source frame. The power source cavity cover may be provided with a counterbore 250 having a terminus 252 within the power source cavity cover 240 . As shown in FIGS. 21 and 22, the counterbore 250 is adapted to receive a switch element. Preferably, the switch element is a dome plate, such as that shown as element 92 in. FIG. 18. Of course, other types of flexible switch plates can be suitably used. As shown in FIG. 23, when the power source cavity cover 240 is positioned on the power source frame 222 , the counterbore 250 is preferably located opposite the power source cavity 224 and includes a throughhole 254 extending into cavity 224 that is located on the side 233 of the power source frame 222 . [0108] Referring back to FIGS. 19 and 20, keyring extension 260 extends from power source frame 222 . Keyring extension 260 includes an outer end 262 adapted to engage and connect to an outer end of a keyring lock of the type shown in FIG. 2. In an embodiment shown in FIGS. 24 and 25, the outer end 262 includes a latch 264 that connects to a latch receptacle 266 of the keyring lock 268 . This configuration provides for a positive lock between the outer end 262 of the keyring extension 260 and the keyring lock 268 . The keyring lock may be attached to the interior of the housing, or to the power source frame, using any suitable means of attachment. Preferably, the keyring lock is springbiased and may pivot about a circular post 270 (shown in FIG. 20) in the same manner as shown in FIG. 9. [0109] Alternatively, as shown in FIGS. 26 a and 26 b , the keyring lock may include a receptacle hood 270 that extends over the receptacle 272 , such that the receptacle hood 270 abuts the keyring extension latch 264 , thus preventing an over-extension of the keyring lock 268 . Preferably, the keyring extension is made of ABS, Acrylonitrile Butadiene Styrene, along with the power source frame, although any suitable nonconductive material may be used. The keyring lock is preferably made of a different material, such as nylon, so that it does not become welded to the keyring extension during ultrasonic welding of the power source frame housing sides. [0110] In yet an additional embodiment, shown in FIGS. 27 through 29, a power source frame 322 may include a magnet cavity 370 positioned in bottom support 335 that is adapted to receive a magnet 372 . The magnet attracts both the power source and the weight, if used, to further maintain the placement of the internal components. In the absence of a power source frame, the magnet is preferably positioned within the housing. In a preferred embodiment, the internal magnet 372 is approximately 0.060 inches thick and a half inch in diameter. The magnet is advantageously made of Neodymium alloyed with iron and boron. Most preferably it is a NEP3042NP Neodymium 30 magnet having a Rockwell C scale hardness of 55 available from Bunting Magnets. It is also preferably nickel plated to protect against corrosion. The magnet weighs only 0.003 pounds and has a holding force of three pounds. The use of an internal magnet allows the outer surfaces of the light to maintain their distinctive smooth lines and allows for engravings or other indicia to be placed on the outer surfaces of the light. With this magnet, the light can be attached to refrigerators, toolboxes, or any metal surface. An adhesive steel disc may be provided that may be mounted on any surface in any location to provide a place to attach the light. For example, the steel disc can be mounted to the interior dashboard of a car to provide a resting place for the light and allow for quick retrieval when needed. [0111] A further alternative embodiment is shown in FIGS. 30 and 31. This embodiment includes a translucent housing 400 . The translucent housing may be made of polycarbonate. The flashlight may be constructed using any of the various embodiments disclosed herein. Preferably it includes a power source frame 410 that may also be made of translucent material. In a preferred embodiment, the flashlight includes a translucent power source frame housing 420 having integral side covers that together completely enclose the power source frame. The housing is preferably made of a colored translucent material that may include a matching colored LED 430 . For example, a flashlight having a red colored translucent housing may be used with a red LED. With the translucent housing, the light emitted from the LED is dispersed throughout the housing to provide an illuminated housing. Alternatively, the housing may be provided with separate side covers that are either translucent or opaque. Different colored LEDs may be used with a different colored housing, as well as different colored side covers to provide a rainbow, or kaleidoscope of colors. Or, if the side covers are opaque, the light is only dispersed throughout the translucent portion of the housing. [0112] In an further alternative embodiment, shown in FIG. 32, flashlight 500 may include a keyring extension 510 extending from the housing, or power source frame if used, and may further include a keyring lock 520 extending from the interior of the housing, or the power source frame if used. The keyring lock 520 is preferably springbiased, or most preferably internally hinged, as shown in FIG. 32. The keyring lock 520 includes an outer end 530 that is biased towards and abuts an outer end 540 of keyring extension 510 . The keyring lock operates to allow a keyring to be slipped between the outer end 530 of the keyring lock and the outer end 540 of the keyring extension 510 . This embodiment also may include side covers 550 that are made of santoprene. [0113] While certain features and embodiments of the invention have been described herein, it will be readily understood that the invention encompasses all modifications and enhancements within the scope and spirit of the present invention.

A flashlight having a light-emitting diode light source with first and second leads extending therefrom, a power source, a power source frame enclosing at least a portion of the power source; a housing containing the light source and power source, a switch located adjacent the power source and operable to close a circuit including the light source and the power source, and wherein one or all of the following may be included 1) a keyring extension extending from a power source frame or the housing with the keyring extension having an opening whereby an article can be attached to the keyring extension and includes a keyring lock wherein upon exerting a force against the keyring lock, the keyring lock is opened to permit the article to be attached to the keyring extension; 2) the housing is comprised of translucent material; and 3) the housing includes at least one side cover which is not integral with the housing and the at least one side cover being selected from anodized aluminum, anodized metal, anodized metal which includes indicia, die struck metal, laser engraved metal, and a side cover having a separate medallion attached thereto.

TECHNICAL FIELD [0001] The present invention relates to normal detection method using distance detectors, a normal detection device, and a machining machine provided with a normal detection function. BACKGROUND ART [0002] In machining, it is important to perform machining according to design drawings and according to machining setting. For that purpose, it is required to precisely find out machining positions, machining directions, and machining amounts with respect to workpieces. [0003] For example, in a structure in which a number of component parts are mechanically coupled together by mechanical coupling parts, such as rivets and fasteners, as in an airframe of an aircraft, it is necessary to perform drilling, which allows the mechanical coupling parts to pass through the respective component parts, with precise machining positions, machining directions, and machining amounts. [0004] When a main wing that is one component part of the aircraft, and a skeleton part or the like are mechanically coupled together by a mechanical coupling part or the like, a protrusion may be formed on the surface of the main wing as the mechanical coupling part protrudes from the surface of the main wing, or a recess may be formed in the surface of the main wing as an attachment hole of the mechanical coupling part becomes deep. The protrusion and recess on the surface of the main wing influence the aerodynamic performance of an airplane. Hence, drilling, which allows a mechanical coupling part to pass through the main wing that is a workpiece, is performed with a precise machining position, a precise machining direction, and a precise machining amount so that the protrusion and the recess are minimized. Here, the machining direction is mainly an angle orthogonal to a workpiece, and it is necessary to obtain the normal vector on a surface to be machined. CITATION LIST Patent Literature [0005] [PTL 1] Japanese Unexamined Patent Application Publication No. 61-269002 [0006] [PTL 2] Japanese Unexamined Patent Application Publication No. 8-71823 SUMMARY OF INVENTION Technical Problem [0007] PTL 1 discloses a normal detection method that obtains the normal vector on the surface to be machined, and PTL 2 discloses a machining machine provided with a normal detection function. [0008] The normal detection method of PTL 1 is a method of obtaining the normal vector on a measured surface of a measurement subject by two opposed contact sensors among a plurality of contact sensors radially installed on a tip surface of an inner tube at one end coming into contact with the measurement subject and two opposed contact sensors installed on two protruding opposed tip surfaces of the outer tube at one end coming into contact with the measurement subject, in a movable normal detection jig in which the inner tube and the outer tube are coaxially fitted to each other and the outer tube is rotatable in a circumferential direction and movable in an axial direction with respect to the inner tube. [0009] This is a method of determining whether the axial direction of the normal detection jig is the same as the normal vector on the measured surface. That is, the axial direction of the normal detection jig should be sought such that the two opposed contact sensors of the inner tube detect the measurement subject and the two contact sensors installed at the tip of the outer tube detect the measurement subject. Hence, the operation for allowing the axial direction of the normal detection jig to coincide with the normal vector on the measured surface will take a substantial time. Additionally, in the normal detection method of PTL 1, it is difficult to automatically control the posture of the normal detection jig. [0010] The machining machine provided with a normal detection function of PTL 2 is a drilling machine provided with a machining jig in which two non-contact sensors are provided at one end and a motor-driven height adjustment mechanism is provided at the other end. The two non-contact sensors are arranged so as to become symmetrical with respect to the drilling tool, and the height adjustment mechanism is arranged so as to line up with the two non-contact sensors and the machining tool. By performing adjustment using the height adjustment mechanism so that measurement distances obtained by the two non-contact sensors become equal to each other, the angle of the machining machine to the surface to be machined is made right-angled. [0011] This is a device that detects perpendicularity with respect to one direction in which the two non-contact sensors and the height adjustment mechanism are lined up. Hence, since the perpendicularity to a direction different from the one direction cannot be detected, it is insufficient for obtaining the normal vector on the surface to be machined with high precision. [0012] The invention has been made in view of the above problems, and an object thereof is to calculate a normal vector on a measured surface with high precision from measurement distances obtained by distance detectors so that it is not necessary to search for the normal vector on the measured surface. Solution to Problem [0013] A normal detection method related to a first aspect of the invention to solve the above problems measures a plurality of distances to a measurement subject using one or a plurality of distance detectors, and obtains a normal vector on a measured surface of the measurement subject from the obtained measurement results. A plurality of measurement points on the measured surface at a plurality of measurement positions are represented by three-dimensional coordinates from the plurality of measurement positions where the distance detectors measure the distances to the measurement subject, and a plurality of measurement results obtained by the distance detectors at the plurality of measurement positions, a straight line connecting, on three-dimensional axes, a first measurement point measured at an arbitrary first measurement position among the plurality of measurement positions by the distance detector and a second measurement point measured at a second measurement position different from the first measurement position is defined as a first vector, a straight line connecting, on three-dimensional axes, the first measurement point and a third measurement point measured at a third measurement position different from the first measurement position and the second measurement position is defined as a second vector, and a normal vector on the measured surface is obtained by determining an outer product of the first vector and the second vector. [0014] In the normal detection method according to a second aspect of the invention to solve the above problems, the first measurement position, the second measurement position, and the third measurement position are selected so that the area of a triangle made with three points of the first measurement position, the second measurement position, and the third measurement position becomes the largest. [0015] In the normal detection method according to a third aspect of the invention to solve the above problems, the distance detectors are radially arranged in eight places including the first measurement position, the second measurement position, and the third measurement position. [0016] In the normal detection method according to a fourth aspect of the invention to solve the above problems, non-contact sensors are used as the distance detectors. [0017] A normal detection device related to a fifth aspect of the invention to solve the above problems includes one or a plurality of distance detectors that measure a distance to a measurement subject; and arithmetic means for representing a plurality of measurement points on the measured surface at a plurality of measurement positions by three-dimensional coordinates from the plurality of measurement positions where the distance detectors measure distances to the measurement subject, and a plurality of measurement results obtained by the distance detectors at the plurality of measurement positions, defining, as a first vector, a straight line connecting, on three-dimensional axes, a first measurement point measured at an arbitrary first measurement position among the plurality of measurement positions by the distance detector and a second measurement point measured at a second measurement position different from the first measurement position, defining, as a second vector, a straight line connecting, on three-dimensional axes, the first measurement point and a third measurement point measured at a third measurement position different from the first measurement position and the second measurement position, calculating a normal vector on the measured surface by an outer product of the first vector and the second vector, and calculating a machining vector passing through a setting point of a machining place using the calculated normal vector. [0018] A machining machine provided with a normal detection function according to a sixth aspect of the invention to solve the above problems includes the normal detection device according to the fifth aspect of the invention, and three-dimensional posture control means for three-dimensionally controlling the posture of the normal detection device and a machining tool to be the machining vector calculated by the arithmetic means. Advantageous Effects of Invention [0019] According to the normal detection method related to the first invention, since the normal vector is calculated from the first vector and the second vector that are not parallel to each other and are different from each other, the normal vector can be obtained with high precision. Additionally, since the normal vector on the measured surface can be calculated from the measurement distances obtained by the distance detectors, when the normal detection method related to the invention is applied to a machining machine or the like, it is easy to automatically control the posture of a machining tool or the like of the machining machine, and it is possible to shorten the working hours, which are taken for controlling the posture of the machining tool or the like of the machining machine so that the machining direction or the like of the machining machine coincides with the normal vector on the measured surface. [0020] According to the normal detection method related to the second invention, the first measurement position, the second measurement position, and the third measurement position are selected so that the area of the triangle made at the three points of the first measurement position, the second measurement position, and the third measurement position becomes the largest, and the first measurement position, the second measurement position, and the third measurement position are spaced apart from each other. Thus, the precision of the normal vector, which is calculated from the measurement distances at the first measurement position, the second measurement position, and the third measurement position obtained by the distance detectors, is improved. [0021] According to the normal detection method related to the third invention, simultaneous measurements are allowed in eight places by using the eight distance detectors that are radially installed. As a result, even when some distance detectors cannot perform effective measurement due to holes, end surfaces, or the like, the normal vector can be obtained from the measurement distances obtained by the other distance detectors that can perform effective measurement. [0022] According to the normal detection method related to the fourth invention, since the operation for bringing contact sensors into contact with a measurement subject is eliminated by using the non-contact sensors as the distance detectors, the working hours for obtaining the normal vector on the measured surface can be shortened. [0023] According to the normal detection device related to the fifth invention, since the normal vector is calculated from the first vector and the second vector that are not parallel and are different, the normal vector can be obtained with high precision. Additionally, since the normal vector on the measured surface can be calculated from the measurement distances obtained by the distance detectors, when the normal detection device related to the invention is applied to a machining machine or the like, it is easy to automatically control the posture of a machining tool or the like of the machining machine, and it is possible to shorten the working hours, which are taken for controlling the posture of the machining tool or the like of the machining machine so that the machining direction or the like of the machining machine coincides with the normal vector on the measured surface. [0024] According to the machining machine provided with a normal detection function related to the sixth invention, the normal vector on the measured surface is calculated by the normal detection device related to the fifth invention, and the posture of the machining tool is controlled in conformity with the calculated normal vector by the three-dimensional posture control means. Thus, the machining tool can be precisely and rapidly made to coincide with the normal vector, and machining in a precise normal direction can be processed. BRIEF DESCRIPTION OF DRAWINGS [0025] FIG. 1 is a conceptual diagram showing measurement using distance detectors related to Example 1. [0026] FIG. 2 is a plan view (as seen from a direction of arrow II in FIG. 3 ) showing the arrangement of the distance detectors in a machining jig related to Example 1. [0027] FIG. 3 is a side view as seen from a direction of arrow III of FIG. 2 . [0028] FIG. 4 is a plan view (as seen from a direction of arrow IV in FIG. 5 ) showing the machining jig related to Example 1 to which a parallel jig is attached. [0029] FIG. 5 is a side view as seen from a direction of arrow V of FIG. 4 . [0030] FIG. 6 is a plan view (as seen from a direction of arrow VI in FIG. 7 ) showing the machining jig related to Example 1 to which an inclined jig is attached. [0031] FIG. 7 is a side view as seen from a direction of arrow VII of FIG. 6 . [0032] FIG. 8A is a schematic view showing an example of the selection of forming a triangle with a largest area, in the arrangement of the distance detectors in the machining jig related to Example 1. [0033] FIG. 8B is a schematic view showing an example of the selection of forming a triangle with a second largest area, in the arrangement of the distance detectors in the machining jig related to Example 1. [0034] FIG. 8C is a schematic view showing an example of the selection of forming a triangle with a third largest area, in the arrangement of the distance detectors in the machining jig related to Example 1. [0035] FIG. 8D is a schematic view showing an example of the selection of forming a triangle with a fourth largest area, in the arrangement of the distance detectors in the machining jig related to Example 1. [0036] FIG. 8E is a schematic view showing an example of the selection of forming a triangle with a fifth largest area, in the arrangement of the distance detectors in the machining jig related to Example 1. DESCRIPTION OF EMBODIMENTS [0037] Hereinafter, examples of a normal detection method related to the invention will be described in detail with reference to the attached drawings. Of course, it is obvious that the invention is not limited to the following examples but various changes can be made without departing from the concept of the invention. Example 1 [0038] A normal detection method related to Example 1 of the invention will be described with reference to FIGS. 1 to 8 . [0039] In the present example, a machining jig 10 including a normal detection mechanism is attached to a machining machine (not shown) so as to allow machining from a normal direction on a measured surface 21 of a measurement subject 20 that is a workpiece. [0040] As shown in FIGS. 1 and 2 , the machining jig 10 includes non-contact sensors 30 that measure a distance to the measurement subject 20 , arithmetic means (not shown) for calculating a normal vector Vn and a machining vector Vm on the measured surface 21 from a measurement distance L obtained by the non-contact sensors 30 , and three-dimensional posture control means (not shown) for three-dimensionally controlling the posture of the machining jig 10 to be in a direction calculated by the arithmetic means, together with the machining machine (not shown). In the machining jig 10 of the present example, eight non-contact sensors 30 a , 30 b , 30 c , 30 d , 30 e , 30 f , 30 g , and 30 h are radially installed on a machining-side tip surface 11 of the machining jig 10 . [0041] Additionally, the machining jig 10 includes a machining-side tip hole 12 through which a parallel jig 40 ( FIGS. 4 and 5 ) performing Z-direction correction in the non-contact sensors 30 a to 30 h installed in the machining jig 10 and an inclined jig 50 ( FIGS. 6 and 7 ) that performing X-direction and Y-direction correction in the non-contact sensors 30 a to 30 h installed in the machining jig 10 are attachable and detachable. Here, the Z direction is a measurement direction of the non-contact sensors 30 a to 30 h , the X direction is an arbitrary direction orthogonal to the Z direction, and the Y-direction is a direction orthogonal to the Z direction and the X direction. In addition, the machining-side tip hole 12 is also used as a hole that allows a machining part of the machining machine (not shown) to pass therethrough during machining. [0042] The parallel jig 40 is a jig that performs the Z-direction correction in the non-contact sensors 30 a to 30 h , and as shown in FIGS. 4 and 5 , has an attachment cylindrical portion 41 to be fitted to the machining-side tip hole 12 of the machining jig 10 , and a Z-direction correction surface 42 that performs the Z-direction correction in the non-contact sensors 30 a to 30 h . If the attachment cylindrical portion 41 of the parallel jig 40 is inserted into the machining-side tip hole 12 of the machining jig 10 and the parallel jig 40 is fixed to the machining jig 10 , the Z-direction correction surface 42 perpendicularly intersects the Z direction that is a direction parallel to the machining-side tip surface 11 of the machining jig 10 , that is, the measurement direction of the non-contact sensors 30 a to 30 h , and is located at an arbitrary distance δz from the machining-side tip surface 11 of the machining jig 10 . In addition, since the Z-direction correction in the eight non-contact sensors 30 a to 30 h is performed, the Z-direction correction surface 42 is broad to such a degree that the eight non-contact sensors 30 a to 30 h can measure a distance to the Z-direction correction surface 42 . [0043] The inclined jig 50 is a jig that performs the X-direction and Y-direction correction in the non-contact sensors 30 a to 30 h , and as shown in FIGS. 6 and 7 , has an attachment cylindrical portion 51 to be fitted to the machining-side tip hole 12 of the machining jig 10 , and an XY-direction correction surface 52 that performs the Z-direction correction in the non-contact sensors 30 a to 30 h . If the attachment cylindrical portion 51 is inserted into the machining-side tip hole 12 and the inclined jig 50 is fixed to the machining jig 10 , the XY-direction correction surface 52 forms an arbitrary angle θ with respect to the machining-side tip surface 11 of the machining jig 10 , and a central portion 53 of the XY-direction correction surface 52 is located at an arbitrary distance δxy from the machining-side tip surface 11 of the machining jig 10 . In addition, since the XY-direction correction in the eight non-contact sensors 30 a to 30 h is performed, the XY-direction correction surface 52 is broad to such a degree that the eight non-contact sensors 30 a to 30 h can measure a distance to the XY-direction correction surface 52 . [0044] The XY-direction correction surface 52 can be attached so as to be parallel to the X direction by providing a protrusion (not shown) on an outer wall surface of the attachment cylindrical portion 51 of the inclined jig 50 , providing a first recess (not shown) in an inner wall surface of the machining-side tip hole 12 of the machining jig 10 and allowing the protrusion of the attachment cylindrical portion 51 of the inclined jig 50 and the first recess of the machining-side tip hole 12 of the machining jig 10 to engage with each other, and the XY-direction correction surface 52 can be attached so as to become parallel to the Y direction by providing a second recess (not shown) at a position rotated by 90° from the first recess in the circumferential direction in the inner wall surface of the machining-side tip hole 12 of the machining jig 10 and by allowing the protrusion of the attachment cylindrical portion 51 of the inclined jig 50 and the second recess of the machining-side tip hole 12 of the machining jig 10 to engage with each other. [0045] First, the Z-direction correction in the non-contact sensors 30 a to 30 h installed in the machining jig 10 , using the machining jig 10 and the parallel jig 40 , will be described with reference to FIG. 5 . [0046] The parallel jig 40 is attached to the machining jig 10 , and the distance to the Z-direction correction surface 42 of the parallel jig 40 is measured by the eight non-contact sensors 30 a to 30 h . The parallel jig 40 and the Z-direction correction surface 42 are formed so that the Z-direction correction surface 42 of the parallel jig 40 has the arbitrary distance 6 z from the machining-side tip surface 11 of the machining jig 10 , and are assembled to the machining jig 10 . Hence, the Z-direction correction in the eight non-contact sensors 30 a to 30 h can be performed by comparison with measurement distances Lza to Lzh to the Z-direction correction surface 42 obtained by the non-contact sensors 30 a to 30 h . That is, the installation positions of the eight non-contact sensors 30 a to 30 h in the Z direction with respect to the machining jig 10 can be precisely found out, relative errors caused by the assembling or the like of the eight non-contact sensors 30 a to 30 h to the machining jig 10 can be corrected for, and Z-direction distance measurement using the non-contact sensors 30 a to 30 h can be precisely performed. [0047] Next, the X-direction correction in the non-contact sensors 30 a to 30 h installed in the machining jig 10 , using the machining jig 10 and the inclined jig 50 , will be described with reference to FIG. 7 . [0048] The inclined jig 50 is attached to the machining jig 10 so that the XY-direction correction surface 52 becomes parallel to the Y direction, and the distance to the XY-direction correction surface 52 of the inclined jig 50 is measured by the eight non-contact sensors 30 a to 30 h . The inclined jig 50 and the XY-direction correction surface 52 are formed so that the XY-direction correction surface 52 has the arbitrary angle θ with respect to the machining-side tip surface 11 of the machining jig 10 and the central portion of the XY-direction correction surface has the arbitrary distance 6 xy from the machining-side tip surface 11 of the machining jig 10 , and are assembled to the machining jig 10 . Hence, the X-direction correction in the eight non-contact sensors 30 a to 30 h can be performed by calculation from measurement distances Lxa to Lxh obtained by the non-contact sensors 30 a to 30 h . That is, the installation positions Xa to Xh of the eight non-contact sensors 30 a to 30 h in the X direction with respect to the machining jig 10 can be precisely found out, relative errors caused by the assembling or the like of the eight non-contact sensors 30 a to 30 h to the machining jig 10 can be corrected for, and X-direction distance measurement using the non-contact sensors 30 a to 30 h can be precisely performed. [0049] Next, the Y-direction correction in the non-contact sensors 30 a to 30 h installed in the machining jig 10 , using the machining jig 10 and the inclined jig 50 , will be described with reference to FIG. 7 . [0050] The inclined jig 50 is attached to the machining jig 10 so that the XY-direction correction surface 52 becomes parallel to the X direction, and the distance to the XY-direction correction surface 52 of the inclined jig 50 is measured by the eight non-contact sensors 30 a to 30 h . The inclined jig 50 is formed so that the XY-direction correction surface 52 has the arbitrary angle θ and the central portion of the XY-direction correction surface has the arbitrary distance xy from the machining-side tip surface 11 of the machining jig 10 , and is assembled to the machining jig 10 . Hence, the Y-direction correction in the eight non-contact sensors 30 a to 30 h can be performed by calculation from measurement distances Lya to Lyh obtained by the non-contact sensors 30 a to 30 h . That is, the installation positions Ya to Yh of the eight non-contact sensors 30 a to 30 h in the Y direction with respect to the machining jig 10 can be precisely found out, relative errors caused by the assembling or the like of the eight non-contact sensors 30 a to 30 h to the machining jig 10 can be corrected for, and Y-direction distance measurement using the non-contact sensors 30 a to 30 h can be precisely performed. [0051] Next, the normal detection method of obtaining the normal vector Vn on the measured surface 21 , using the machining jig 10 , will be described with reference to FIG. 1 . [0052] The normal vector Vn is obtained by selecting three non-contact sensors from the eight non-contact sensors 30 a to 30 h installed in the machining jig 10 , and performing calculation from measurement distances La, Ld, and Lf obtained by non-contact sensors 30 a , 30 d , and 30 f of a selected combination to be described below, and installation positions (a first measurement position, a second measurement position, and a third measurement position) Pa (Xa, Ya), Pd (Xd, Yd), and Pf (Xf, Yf) of the non-contact sensors 30 a , 30 d , and 30 f of the selected combination. [0053] Measurement distances La to Lh to the measurement subject 20 is measured using the eight non-contact sensors 30 a to 30 h installed in the machining jig 10 . In the eight non-contact sensors 30 a to 30 h installed in the machining jig 10 , the number of combinations of selecting three non-contact sensors is fifty six ways, and is five ways if being classified according to the areas of triangles made by the respective combinations. [0054] For example, the number of combinations of obtaining triangles with a largest area is eight ways of selecting the non-contact sensors 30 a , 30 d , and 30 f , or the like, the number of combination of obtaining triangles with a second largest area is eight ways of selecting the non-contact sensors 30 a , 30 c , and 30 g , or the like, the number of combinations of obtaining triangles with a third largest area is sixteen ways of selecting the non-contact sensors 30 a , 30 b , and 30 f , or the like, the number of combinations of obtaining triangles with a fourth largest area is sixteen ways of selecting the non-contact sensors 30 a , 30 b , and 30 g , or the like, and the number of combinations of obtaining triangles with a smallest area is eight ways of selecting the non-contact sensors 30 a , 30 b , and 30 h , or the like. [0055] All the measurement distances La to Lh to the measurement subject 20 measured by the eight non-contact sensors 30 a to 30 h are not necessarily effective. That is, a hole is made at measurement points Qa to Qh of the measurement subject 20 or the measurement points Qa to Qh deviate from an end portion of the measurement subject 20 . However, the measurement distances La to Lh that are measurement results by all the non-contact sensors 30 a to 30 h are not necessarily obtained, and it is sufficient if a required number of effective measurement distances La to Lh are valid. When a required number of effective measurement distances La to Lh are not value, the required number of effective measurement distances La to Lh are valid by slightly translating the machining jig 10 and performing measurement using the non-contact sensors 30 a to 30 h. [0056] The non-contact sensors 30 a to 30 h to be used for the calculation of the normal detection are selected so that the area made by three non-contact sensors 30 selected from the non-contact sensors 30 a to 30 h by which the measurement distances La to Lh that are effective measurement results are obtained becomes the largest. [0057] Measurement points (a first measurement point, a second measurement point, and a third measurement point) Qa, Qd, and Qf on the measured surface 21 to be measured by the non-contact sensors 30 a , 30 d , and 30 f of the selected combination are represented by three-dimensional coordinates from the installation positions Pa (Xa, Ya), Pd (Xd, Yd), and Pf (Xf, Yf) of the non-contact sensors 30 a , 30 d , and 30 f in XY directions, and the measurement distances La, Ld, and Lf obtained by the non-contact sensors 30 a , 30 d , and 30 f. [0058] Measurement point Qa: (Xa, Ya, Za) [0059] Measurement point Qd: (Xd, Yd, Zd) [0060] Measurement point Of: (Xf, Yf, Zf) [0061] A vector (first vector) Vad connecting the measurement point Qa and the measurement point Qd measured by two arbitrary non-contact sensors 30 a and 30 d among the non-contact sensors 30 a , 30 d , and 30 f of the selected combination, and a vector (second vector) Vaf connecting the measurement point Qa and measurement point Qf measured by two arbitrary non-contact sensors 30 a and 30 f among the non-contact sensors 30 a , 30 d , and 30 f of the selected combination are calculated on the basis of the three-dimensional coordinates. [0000] Vad = s  ( Xd - Xa Yd - Ya Zd - Za ) + ( Xa Ya Za )   Vaf = t  ( Xf - Xa Yf - Ya Zf - Za ) + ( Xa Ya Za ) [ Formula   1 ] [0062] Here, s and t are arbitrary real numbers. [0063] The vector Vn that is an outer product of the vector Vad and the vector Vaf is calculated. The vector Vn is a direction vector orthogonal to the vector Vad and the vector Vaf, and represents a normal vector on the measured surface 21 . [0000] Vn =  Vaf × Vad =  u   ( ( Yf - Ya )  ( Zd - Za ) - ( Yd - Ya )  ( Zf - Za ) ( Zf - Za )  ( Xd - Xa ) - ( Zd - Za )  ( Xf - Xa ) ( Xf - Xa )  ( Yd - Ya ) - ( Xd - Xa )  ( Yf - Ya ) ) + ( Xa Ya Za ) [ Formula   2 ] [0064] Here, u is an arbitrary real number. [0065] The machining vector Vm passing through a set point Rm (Xm, Ym, Zm) of a machining place is calculated from the calculated normal vector Vn. [0000] Vm = v   ( ( Yf - Ya )  ( Zd - Za ) - ( Yd - Ya )  ( Zf - Za ) ( Zf - Za )  ( Xd - Xa ) - ( Zd - Za )  ( Xf - Xa ) ( Xf - Xa )  ( Yd - Ya ) - ( Xd - Xa )  ( Yf - Ya ) ) + ( Xm Ym Zm ) [ Formula   3 ] [0066] Here, v is an arbitrary real number. [0067] The posture of the machining jig 10 is controlled by three-dimensional posture control means so that the central axis of the machining jig 10 coincides with the obtained machining vector Vm. At this time, the measurement distances La, Ld, and Lf obtained by the opposed non-contact sensors 30 a , 30 d , and 30 f become the same value. [0068] By virtue of the above-described normal detection method and three-dimensional posture control, the normal vector Vn on the measured surface 21 can be obtained with high precision, the orientation of the machining jig 10 and the orientation of a machining tool of the machining machine (not shown) can be made to coincide with the calculated normal vector Vn, and machining in a precise normal direction can be performed. [0069] Additionally, the normal vector Vn on the measured surface 21 can also be obtained with higher precision not only by calculating the normal vector Vn from the measurement distances La, Ld, and Lf obtained by the non-contact sensors 30 a , 30 d , and 30 f of the selected combination and the installation positions Pa (Xa, Ya), Pd (Xd, Yd), and Pf (Xf, Yf) of the non-contact sensors 30 a , 30 d , and 30 f of the selected combination, but also, for example, by calculating a normal vector V′n from the measurement distances Lb, Le, and Lg obtained by the non-contact sensors 30 b , 30 e , and 30 g and the installation positions Pb (Xb, Yb), Pe (Xe, Ye), and Pg (Xg, Yg) of the non-contact sensors 30 b , 30 e , and 30 g of the selected combination, and taking the average of the plurality of normal vectors Vn and V′n. [0070] In addition, by repeating the operation of the normal detection method and three-dimensional posture control of the present example, the normal vector Vn on the measured surface 21 can be obtained with higher precision, and the machining jig 10 and the machining tool of the machining machine (not shown) can be made to coincide with the normal vector Vn that is calculated with higher precision. [0071] Since the normal detection is influenced by the measurement distances La to Lh obtained by the non-contact sensors 30 a to 30 h , precise measurement using the non-contact sensors 30 a to 30 h is required. Hence, in the present example, the X-direction, Y-direction, and Z-direction corrections of the eight non-contact sensors 30 a to 30 h attached to the machining jig 10 are performed. Of course, if precise measurement and installation using the non-contact sensors 30 are allowed in advance, the X-direction, Y-direction, and Z-direction corrections as in the present example are unnecessary. [0072] In the present example, the eight non-contact sensors 30 a to 30 h are radially installed as distance detectors to perform the normal detection, but the invention is not limited to this. For example, by making the non-contact sensors 30 movable, the normal vector Vn may be calculated from a plurality of measurement results measured at a plurality of measurement positions by one non-contact sensor 30 or the normal vector Vn may be calculated from measurement results using contact sensors as the distance detectors. [0073] Additionally, in the present example, the normal vector Vn is obtained using the machining jig 10 including the normal detection mechanism, but the invention is not limited to this. For example, the normal detection may be performed without using the machining jig 10 by providing the machining machine with the distance detectors, the arithmetic means, and the three-dimensional posture control means. INDUSTRIAL APPLICABILITY [0074] The normal detection method related to the invention can detect a normal vector on a target surface in a short time with high precision, and is very useful for the drilling that performs drilling in an aircraft main wing or the like. REFERENCE SIGNS LIST [0000] 10 : MACHINING JIG 11 : MACHINING-SIDE TIP SURFACE 12 : MACHINING-SIDE TIP HOLE 20 : MEASUREMENT SUBJECT 21 : MEASURED SURFACE 30 : NON-CONTACT SENSOR 40 : PARALLEL JIG 41 : ATTACHMENT CYLINDRICAL PORTION 42 : Z-DIRECTION CORRECTION SURFACE 50 : INCLINED JIG 51 : ATTACHMENT CYLINDRICAL PORTION 52 : XY-DIRECTION CORRECTION SURFACE 53 : CENTRAL PORTION

A normal detection method for measuring the distance to a measurement subject using one or more distance detectors, and obtaining a normal vector (Vn) on the measured surface of the measurement subject from the obtained measurement result (L), wherein: within a three-dimensional space, the straight line linking a first measurement point (Qa) measured at a first measurement position (Pa) using the distance detector and a second measurement point (Qd) measured at a second measurement position (Pd) different from the first measurement position (Pa) is set as a first vector (Vad); the straight line linking the first measurement point (Qa) and a third measurement point (Qf) measured at a third measurement position (Pf) different from the first measurement position (Pa) and the second measurement position (Pd) as a second vector (Vaf); and a normal vector (Vn) on the measured surface is obtained by determining the vector product of the first vector (Vad) and the second vector (Vaf).

TECHNICAL FIELD OF THE INVENTION [0001] This invention relates generally to a portable vacuum canister capable of interconnection with and deployment of waste into a sink drain having a waste grinder in direct communication with the sink drain flange covering a sink drain opening. The portable vacuum canister is used for vacuuming debris and dumping the debris into a garbage disposal or waste grinder associated with the sink for grinding of the debris, flushing and release into a municipal waste stream or septic system. BACKGROUND OF THE INVENTION [0002] Vacuum cleaning devices are designed by and large to operate by suctioning dust or debris from a surface. The general theory underlying the concept behind conventional vacuum cleaning devices is well-known. Typically, vacuum cleaning devices use some form of an electromechanical mechanism to create a partial vacuum to suction various kinds of particles into the vacuum cleaning device. Air pumps function by transferring air load from an inlet port to an outlet port (exhaust). The transfer of air load creates a region of lower pressure. The pressure gradient between this region of lower pressure and the ambient pressure creates suction, whereby particles are propelled toward the lower pressure region. The greater the pressure difference between the region of lower pressure and the region of ambient pressure, the greater the suction. [0003] From this fundamental principle of fluid dynamics, various prior vacuum cleaning devices have been developed to suction particles, with a large majority of these vacuum cleaning devices designed to suction debris from floors and carpets. Generally, the most popular current vacuum cleaning devices fall into one of several design categories: upright vacuum cleaners, hand-held vacuum cleaners, canister vacuum cleaners, backpack vacuum cleaners, and central vacuum systems, wherein a central location in a building provide vacuum inlets at strategic places throughout a building. [0004] In the specialized field encompassing vacuum devices designed specifically for suctioning debris from kitchen countertops, stoves, sinks and the like, and thereafter discharging the debris into a garbage disposal, the scope of the prior art is limited and includes especially few references. U.S. Pat. No. 6,434,783 to Arnold teaches of a vacuum system that employs a hose to suction waste materials from a sink. The waste materials are then transferred to a waste container. Similarly, U.S. Pat. No. 6,691,939 to Grimes teaches of a hose that sucks materials via a vacuum generator into a grinder/garbage disposal. Another reference, U.S. Pat. No. 4,641,392 to Huisma, teaches of a central vacuum system, wherein a vacuum tool is employed to suction debris from the kitchen sink area to the sewage system via conduits and a separator. [0005] The prior art described above suffers various deficiencies in its application of vacuuming debris from sinks and thereafter discharging the debris to a garbage disposal in a sink drain. Specifically, the prior art does not teach of a portable vacuum canister with an open bottom that is specially designed to adapt and slide into an existing sink drain flange in communication with a grinder or garbage disposal opening, such that debris, vacuumed by a hand-held hose, is directed into a disposal, ground up, and sent and washed down the drain. Accordingly, there is a need for a relatively simple, inexpensive and portable vacuum canister that can vacuum and dispose of debris into a garbage disposal in an efficient and non-labor intensive manner. SUMMARY OF INVENTION [0006] In accordance with the invention, there is provided a portable vacuum canister specially designed to correspondingly engage the opening of a sink drain flange covering a sink drain opening which is interconnected with a garbage disposal. The vacuum canister employs a suction hose for vacuuming debris; an airblower for generating vacuum; optionally a float cage with a float ball for permitting wet vacuum; a cyclone-shaped funnel for achieving constant suction, better dust separation and increased suction power; and an internal discharge control for selectively controlling discharge from the bottom of the vacuum canister during vacuum operation. [0007] The vacuum canister invention has many practical applications. The vacuum canister can be used for fast cleaning. In particular, the vacuum canister can be used to pick up and quickly dispose of biodegradable food, water and drinks that are on kitchen sinks, counter tops, toasters, cook tops, cook top hoods, ovens, cabinets, drawers, floors, high chairs, and any other conceivable object that would reside near a sink. [0008] The scope of the invention is indicated in the appended claims. It is intended that all changes or modifications within the meaning and range of equivalents are embraced by the claims. [0009] The foregoing and other features and advantages of the invention are apparent from the following detailed description of exemplary embodiments, read in conjunction with the accompanying drawings. The detailed description and drawings are merely illustrative of the invention rather than limiting, the scope of the invention being defined by the appended claims and equivalents thereof. BRIEF DESCRIPTIONS OF THE DRAWINGS [0010] The foregoing summary, as well as the following detailed description of preferred embodiments of the invention, will be understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings embodiments which are presently preferred. It should be understood, however, that the invention is not limited to the precise arrangements and configurations shown. [0011] FIG. 1A depicts an overall diagrammatic view of the inventive vacuum canister in operable connection with a sink drain flange and garbage disposal associated therewith. [0012] FIG. 1B provides an exploded view of the exterior housing for the inventive vacuum canister. [0013] FIG. 1C is a side elevational view illustrating a vacuum hose with attachments and accessories operable with the vacuum canister of the present invention. [0014] FIG. 1D is a perspective view illustrating airflow and debris movement within the inventive vacuum canister. [0015] FIG. 1E is a top elevational view, partial fragmentary view of an upper portion of the inventive vacuum canister. [0016] FIG. 2A is a perspective partially exploded view of an embodiment of the inventive vacuum canister having a backflow-flap-controlled discharge opening. [0017] FIG. 2B is a perspective view of an alternative embodiment of the inventive vacuum canister having a float-ball-valved discharge opening. [0018] FIG. 2C is a perspective view of another alternative embodiment of the inventive vacuum canister having a rotating cam valved discharge opening. [0019] FIG. 2D is a perspective view of yet another alternative embodiment of the inventive vacuum canister having a mechanical-dump-basket-controlled discharge opening. [0020] FIG. 3A is a perspective view illustrating yet another embodiment of the inventive vacuum canister having a backflow-flap-controlled discharge offset from center. [0021] FIG. 3B is a closer perspective view of the vacuum canister embodiment illustrated in FIG. 3A . [0022] FIG. 3C provides an overall diagrammatic view of the vacuum canister embodiment of FIG. 3A in operable connection with a drink drain flange and garbage disposal associated therewith. [0023] FIG. 4A is a perspective view illustrating yet another embodiment of the inventive vacuum canister having a paddle impeller for controlling discharge. [0024] FIG. 4B is a closer perspective view of the discharge control employed by the vacuum canister embodiment of FIG. 4A [0025] FIG. 4C is a perspective view of an impeller of the inventive vacuum canister embodiment of FIG. 4A . [0026] FIG. 4D is an exploded view of the impeller system of the vacuum canister embodiment of FIG. 4A incorporating a fan cage. [0027] FIG. 4E is an exploded view of the impeller system of the vacuum canister embodiment of FIG. 4A incorporating fan blades. [0028] FIG. 4F is a side view of the impeller system illustrated in FIG. 4E . [0029] FIG. 5 is a perspective view illustrating yet another embodiment of the inventive vacuum canister having an airblower mechanism. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0030] The invention is directed to a vacuum canister designed for vacuuming materials, such as particulates and/or fluids, from surfaces and transporting the materials to a sink drain having a grinder or garbage disposal mechanism coupled to the sink drain flange, releasing the materials through the sink drain flange and drain opening and into the grinder or garbage disposal mechanism for grinding an disposal into a municipal waste stream or septic system. FIG. 1A illustrates one preferred embodiment of the invention. The vacuum canister device 100 has two chambers, an upper first chamber 140 that is formed at an upper section of the vacuum canister 100 and a lower second chamber 150 that is formed at a lower section of the vacuum canister 100 . The upper first chamber 140 possesses a substantially cylindrical shape, while the lower second chamber 150 possesses a substantially frustroconical shape. A top region of the upper first chamber 140 is occupied by a vacuum generating element 130 . This vacuum generating element 130 can be an airblower or any other electromechanical mechanism that generates vacuum inside the canister device 100 . A standard airblower can include a motor powered fan or impeller enclosed in a blower housing. Inside the upper chamber 140 , it is desirable to provide a removable filter housing 160 with a float ball 165 is provided to allow for wet vacuuming. [0031] FIG. 11B provides an exploded view of the canister's casing. Suction hose 120 is interconnected with the upper first chamber 140 . Preferably, the suction hose 120 is formed of a lightweight and flexible material, such as polyvinyl chloride, rubber or any material widely known in the vacuum hose art, to allow for easy handling. Naturally, a person skilled in the art could also select another material not described above (such as soft flexible metal) which has been associated with vacuum hoses. Although not shown, the vacuum hose 120 can also be corrugated, so that it is shaped to have folds, ridges or grooves. As shown on FIG. 1C , the suction hose 120 is provided a vacuum head 121 , designed to possess a large surface area for vacuuming even large pieces of debris. Additionally, various attachments can be appended to the suction hose 120 and/or vacuum head 121 to provide for additional cleaning options. For example, the vacuum head 121 can be fastened with a scouring pad/sponge 122 , formed of tough fibers and abrasives, for scouring pots and pans. Likewise, a cleaning fluid dispenser 123 can also be employed for dispensing cleaning fluid to the vacuum head 121 via a fluid carrying hose 124 . Additionally, an on/off switch can be designed to be on the end of the suction hose 120 near the vacuum head 121 , instead of on the vacuum canister 100 itself, so that a user can effortlessly turn on/off vacuuming. Although not shown in the drawings, the suction hose 120 can also be designed to be retractable to the vacuum canister 100 , thereby providing easier use to the user. [0032] Referring back to FIG. 1A , the lower second chamber 150 possesses a substantially conical shape. Near the bottom of the lower second chamber 150 , a discharge control 170 is provided to close shut what would otherwise be a bottomless canister. When the discharge control 170 is in an open state, particles, suctioned through suction hose 120 and transferred down the vacuum canister 100 , pass through a flange 190 a and are discharged into a drain 182 of a kitchen sink 181 . Therefrom, the particles descend to a garbage disposal 183 , installed under the kitchen sink 181 , where the particles are ground up and shredded into small pieces, so they can be passed through plumbing without clogging. [0033] FIG. 1D provides a closer view of the above-described embodiment of the invention. Additionally, FIG. 1D illustrates the air pathway taken by particles and fluids suctioned from a vacuum head 121 on suction hose 120 . Initially, the particles enter through a vacuum head 121 of the suction hose 120 . Thereafter, the particles pass through the length of the suction hose and enter the first upper chamber 140 of the vacuum canister device 100 . FIG. 1E provides a top view of the upper first chamber 140 . Immediately upon entering the upper first chamber 140 , the incoming particles crash hard against a wall of upper first chamber 140 and into the air already being evacuated through the spinning downward spiral action inside the cyclone. The resulting crash in turbulence breaks the heavier and lighter particles apart, and the spinning air throws the heavy particles outward against the cyclone walls. Air flow at the cyclone walls is slowed by friction. As a result, heavier particles get trapped in the slower moving air. Slowly, gravitational forces pull these heavier particles down. The cone-shaped bottom of the cyclone-shaped vacuum canister is designed to be angled at a proper degree to keep the air speed constant. This design keeps the heavier particles pressed tightly to the cyclone walls of the lower second chamber 150 . As a result, the heavier particles slide downward and along the cyclone walls of the lower second chamber 150 . Eventually, these heavier particles fall and become trapped at the bottom of the vacuum canister 100 . Near the bottom of the cone is an area called a reversal point where the spinning air without the heavier particles reverses direction. This clean air then spirals up through the center of the cyclone and then exits through the cyclone outlet through the exhaust. [0034] At the bottom of the lower second chamber 150 , a discharge control 170 is employed for controlling the opening and closing of the vacuum canister 100 . A flange 190 a is provided for discharging particles and fluids from the vacuum canister 100 . The flange 190 a is designed to fittingly and sealingly engage the drain 182 of a sink 181 and is thereby interconnected to a garbage disposal 183 . [0035] In one embodiment, the bottom of the vacuum canister 100 is closed during vacuum operation and opened when vacuum operation is off. In this particular embodiment, closing shut the bottom of the vacuum canister 100 during operation helps the vacuum canister 100 sustain the pressure gradient needed to generate suction. After operation, when the pressure gradient is no longer necessary, the discharge control 170 opens the bottom of the vacuum canister 100 to permit dumping of debris into the drain 182 and subsequently into the garbage disposal 183 . [0036] Various possible discharge controls 170 are available. In the embodiment of FIG. 2A , a backflow valve 171 a is used to control flow of debris coming out of the vacuum canister 100 . Essentially, the backflow valve 171 a prevents fluids from flowing in a direction opposite that of intended flow. Thus, the backflow valve 171 a allows fluids to flow in only one direction, namely in the direction of discharge. To achieve this control, the backflow valve 171 a uses a backflow flap 172 a , capable of two possible positions, an opened position and a closed position. The backflow flap 172 a is fastened to a hinged spring. In the embodiment of FIG. 2A , the opening and closing of the backflow flap 172 a is controlled by suction. During vacuum operation, suction causes the backflow flap 172 a to be lifted into a closed position. This action temporarily causes a vacuum trap. The closing of the discharge control 170 of the vacuum canister 100 allows for particles to be collected on a collection bin 173 a with a flap dam 174 located at the lower portion of the collection bin 173 a . When vacuum operation shuts down, natural gravitational forces and the lack of suction causes the backflow flap 172 a to slide down and descend into an opened position. Accordingly, particles accumulated in the collection bin 173 a falls downwards through the backflow valve 171 a and into the drain 182 . [0037] Referring to FIGS. 2B-2D , alternative discharge controls 170 are shown, wherein the same or similar reference numbers refer to the same or similar structure. [0038] In the alternative discharge control 170 embodiment of FIG. 2B , a float ball 176 is enclosed inside a float ball cage 177 . The float ball cage 177 extends upwards and borders a float ball dam 175 . During vacuum operation, the float ball 176 is suctioned upwards thereby closing shut the discharge control 170 and thus the bottom of the vacuum canister 100 . When vacuum operation shuts down, natural gravitational forces and the lack of suction causes the float ball 176 to descend into a lower position, thereby allowing particles accumulated on the collection bin 173 a to fall downwards through the float ball dam 175 into the drain 182 . [0039] FIG. 2C illustrates another possible discharge control 170 . In this embodiment, a rotating cam 178 or slide gate valve is used to open or close the bottom of the vacuum canister. A user could open and close the bottom of the vacuum canister 100 by manually turning the rotating cam. Similarly, in the discharge control 170 illustrated in FIG. 2D , a mechanical dump basket 179 is used to close shut the bottom of the vacuum canister 100 . After vacuum operation is over, a user could take out the mechanical dump basket 179 to manually dump the collected debris into a drain 182 . [0040] In the preferred embodiment illustrated in FIG. 3A , the vacuum canister 100 is designed to have an overall cylindrical shape. In contrast to the above-mentioned embodiments previously described, wherein the upper portion of the vacuum canister is formed in a cylindrical shape while the lower portion of the vacuum canister is formed in a conical-cyclonic shape, the entire vacuum canister 100 embodied in FIG. 3A , from top to bottom, is formed exteriorly in a substantially cylindrical shape. This cylindrical-shape feature enhances stability of the vacuum canister 100 by lowering the vacuum canister's center of gravity. Accordingly, the vacuum canister 100 is less likely to rock back and forth during operation. In this preferred embodiment, vacuum generating element 130 is situated at the top of the vacuum canister 100 . The vacuum generating element 130 creates vacuum through a motor 131 connected to an impeller/airblower 132 by a rod 133 . An exhaust outlet 134 is provided for releasing air. The exhaust outlet 134 interconnects a filter receiver 135 , which is sized to slidably receive a filter 136 . Similar to the above-mentioned embodiments, a cone-shaped funnel 137 is employed to generate the cyclone action that is effective for achieving constant suction, better dust separation, and increased suction power. Dead spaces 138 are incorporated into the vacuum canister 100 to provide the vacuum canister 100 with an exterior cylindrical shape. These dead spaces 138 are positioned between the cone-shaped funnel 137 and the shell outward wall 139 . The dead spaces can be left empty with air, or they can be filled with sound reducing materials to drown out noise generated during operation of the vacuum canister 100 . [0041] Just like the embodiments described above, the bottom of the vacuum canister 100 embodiment of FIG. 3A includes a discharge control 170 . Similar to the embodiment of FIG. 2A , a backflow valve 171 b with backflow flap 172 b is adopted for controlling the discharging of particles and fluids. The backflow flap 172 b is capable of two possible positions, an opened position and a closed position. The backflow flap 172 b is fastened to a hinged spring. In this preferred embodiment, the opening and closing of the backflow flap 172 b is controlled by vacuum suction. During vacuum operation, vacuum suction causes the backflow flap 172 b to be lifted into a closed position. This action temporarily causes a vacuum trap. The closing of the discharge control 170 allows for particles to be collected on a chute 173 b , which is positioned below the cone-shaped funnel 137 . When vacuum operation shuts down, natural gravitational forces and the lack of suction will cause the backflow flap 172 b to slide down and descend into an opened position. Accordingly, particles and fluids accumulated in the discharge chute 173 b fall down through the backflow valve 171 b and into the drain 182 . A flange 190 b is provided for discharging particles and fluids from the vacuum canister 100 . The flange 190 b is designed to fittingly and sealingly engage the drain 182 of a sink 181 and is thereby interconnected to a garbage disposal 183 . In the embodiment shown in FIG. 3A , the flange 190 b is designed to be offset from the center of the vacuum canister bottom 191 . This design makes it easier for a user to place and fit the vacuum canister over the drain 182 . A closer inside view of the vacuum canister embodiment of FIG. 3A is provided in FIG. 3B . FIG. 3C provides an exterior view of the vacuum canister embodiment illustrated in FIG. 3A . [0042] FIG. 4A illustrates another embodiment of the invention. The vacuum canister device 200 retains a substantially cylindrical shape, except for the portion near the bottom of the vacuum canister. The top portion of the vacuum canister is occupied by a vacuum generating element 230 . As described above, the vacuum generating element 230 can be an airblower or any other contraption that generates vacuum inside the canister 200 . The standard airblower can include a motor powered fan or impeller 232 enclosed in a blower housing. The suction hose 220 is interconnected with the upper portion of the vacuum canister 200 . The pathway shown in FIG. 1E and previously described is also applicable to the embodiment of FIG. 4A . As the particles and fluids enter the cyclone section 237 of the vacuum canister 200 , the particles and fluids are separated in a manner similar to that described above for other embodiments. The exhaust air travel upwards and pass through a screen 234 and into a chamber 236 . From there, the exhaust air enters a channel tube 201 . In contrast, the heavier particles fall downwards in a spiraling manner and exits the cyclone section 237 into a collection chamber 250 . [0043] The embodiment of FIG. 4A differs from the previously described embodiments in the discharge control 270 employed for discharging particles and fluids. The embodiment of FIG. 4A uses a paddle impeller 271 situated at the bottom portion of the vacuum canister 200 . The paddle impeller 271 is formed with a plurality of paddles 272 that revolves in a spinning manner. As illustrated in FIG. 4F , with each rotation, the paddles collect particles 281 and fluids from a collection chamber 250 when in an upward-facing state and empty particles 281 and fluids when in a downward-facing state. The discharged particles and fluids pass through a discharge chamber 280 before exiting the vacuum canister through a flange 290 . The paddle impeller 271 can be designed to rotate in a clockwise direction or in a counterclockwise direction. As illustrated in FIG. 4A , the exhausted air generated by the vacuum generating element 230 is captured and sent down a channel tube 201 . This exhaust air blows on the fan cage 273 of the paddle impeller 271 thus powers the paddle impeller 271 . Thereafter, exhausted air continues through inner carry tube 202 and passes through a connecting tube 203 before exiting into the direction of the rotating paddles 272 . As it exits the connecting tube 203 , the exhaust air blows trapped particles off the rotating paddles 272 , thereby cleaning the rotating paddles 272 . [0044] FIG. 4B gives a closer view of the discharge control 270 employed by the vacuum canister 200 embodiment of FIG. 4A . A person of ordinary skill in the art would recognize that various types of fan contraptions could be used to capture the energy from the exhaust air and transfer this energy into rotational movement of the paddle impeller 271 . For instance, fan blades 274 can be used in lieu of a fan cage 273 for capturing the energy necessary to power the paddle impeller 271 . FIG. 4C presents a perspective view of the paddle impeller 271 comprising of fan blades 274 joined to the inner carry tube 202 that is connected to a plurality of paddles 272 . FIG. 4D provides an exploded view of the paddle impeller 271 . The paddle impeller 271 is comprised of the fan cage 273 , the carry tube 202 , and paddles 272 . Alternatively, as shown in FIG. 4E , when fan blades are 274 are used, the paddle impeller 271 would comprise of fan blades 274 , the carry tube 202 , and paddles 272 . [0045] FIG. 5 illustrates another inventive embodiment of the vacuum canister 300 . As shown in FIG. 5 , the vacuum canister device 300 possesses a substantially cylindrical shape. A vacuum generating element 330 is used to create vacuum. This vacuum generating element 330 can be an airblower or any other contraption that suctions particles into the vacuum canister 300 via a suction hose 320 and a suction inlet 321 interconnected to the vacuum canister 300 and simultaneously blows these particles out of the vacuum canister 300 through a flange 390 . The standard airblower can include a motor 331 powering an impeller 332 or fan rotating via a rod 333 . The airblower is enclosed in a blower housing. The exhaust air vent out to the side through a filter 336 . Additionally, insulation 308 can be provided to lessen the noise stemming from the motor during operation. [0046] Essentially, the invention embodied in FIG. 5 operates by having a motor 331 spin an impeller 332 or fan, thereby creating suction and pulling all air, particles, and fluids into the vacuum canister 300 through the impeller 332 or fan. Simultaneously, the motor creates a blowing action, whereby air, particles, and particles are blown out of the vacuum canister 300 into the sink drain 382 and eventually into the garbage disposal 383 . Unlike previous inventive embodiments, the vacuumed particles and fluids are not held or stored inside the vacuum canister 300 . Thus, a discharge control, like those in the previous embodiments, may not be necessary. [0047] The above-described vacuum canisters and methods are example implementations. The implementations illustrate possible approaches for removing debris from a sink area and discharging the debris into a vacuum canister designed to fittingly and sealingly engage a sink drain. The actual implementation may vary from the configurations discussed. Moreover, various other improvements and modifications to this invention may occur to those skilled in the art, and those improvements and modifications will fall within the scope of this invention as set forth in the claims below. [0048] The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. Therefore, the scope of the invention is not limited to the specific exemplary embodiment described above. All changes or modifications within the meaning and range of equivalents are intended to be embraced herein. [0049] As used in this application, the articles “a” and “an” refer to one or more than one (i.e., to at least one) of the grammatical objects of the article. By way of example, “an element” means one element or more than one element.

A portable vacuum canister is disclosed for vacuuming debris by a hand-held suction hose and for transferring the debris down through the vacuum canister and into an existing garbage disposal for grinding, where it is then washed down the drain. The vacuum canister adapts and slides into an existing disposal opening.

This application is a continuation of U.S. Ser. No. 08/544,837, filed Oct. 18, 1995, now U.S. Pat. No. 5,845,215. BACKGROUND Applicants' invention relates to electrical telecommunication, and more particularly to wireless communication systems, such as cellular and satellite radio systems, for various modes of operation (analog, digital, dual mode, etc.), and access techniques such as frequency division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA), and hybrid FDMA/TDMA/CDMA. The specific aspects of the invention are directed to techniques for enhancing procedures for reception and transmission of information. A description follows which is directed to environments in which this invention may be applied. This general description is intended to provide a general overview of known systems and associated terminology so that a better understanding of the invention can be obtained. In North America, digital communication and multiple access techniques such as TDMA are currently provided by a digital cellular radiotelephone system called the digital advanced mobile phone service (D-AMPS), some of the characteristics of which are specified in the interim standard TIA/EIA/IS-54-B, "Dual-Mode Mobile Station-Base Station Compatibility Standard", published by the Telecommunications Industry Association and Electronic Industries Association (TIA/EIA), the disclosure of which is expressly incorporated here by reference. Because of a large existing consumer base of equipment operating only in the analog domain with frequency-division multiple access (FDMA), TIA/EIA/IS-54-B is a dual-mode (analog and digital) standard, providing for analog compatibility together with digital communication capability. For example, the TIA/EIA/IS-54-B standard provides for both FDMA analog voice channels (AVC) and TDMA digital traffic channels (DTC). The AVCs and DTCs are implemented by frequency modulating radio carrier signals, which have frequencies near 800 megahertz (MHz) such that each radio channel has a spectral width of 30 kilohertz (KHz). In a TDMA cellular radiotelephone system, each radio channel is divided into a series of time slots, each of which contains a burst of information from a data source, e.g., a digitally encoded portion of a voice conversation. The time slots are grouped into successive TDMA frames having a predetermined duration. The number of time slots in each TDMA frame is related to the number of different users that can simultaneously share the radio channel. If each slot in a TDMA frame is assigned to a different user, the duration of a TDMA frame is the minimum amount of time between successive time slots assigned to the same user. The successive time slots assigned to the same user, which are usually not consecutive time slots on the radio carrier, constitute the user's digital traffic channel, which may be considered a logical channel assigned to the user. As described in more detail below, digital control channels (DCCs) can also be provided for communicating control signals, and such a DCC is a logical channel formed by a succession of usually non-consecutive time slots on the radio carrier. In only one of many possible embodiments of a TDMA system as described above, the TIA/EIA/IS-54-B standard provided that each TDMA frame consists of six consecutive time slots and has a duration of 40 milliseconds (msec). Thus, each radio channel can carry from three to six DTCs (e.g., three to six telephone conversations), depending on the source rates of the speech coder/decoders (codecs) used to digitally encode the conversations. Such speech codecs can operate at either full-rate or half-rate. A full-rate DTC requires twice as many time slots in a given time period as a half-rate DTC, and in TIA/EIA/IS-54-B, each full-rate DTC uses two slots of each TDMA frame, i.e., the first and fourth, second and fifth, or third and sixth of a TDMA frame's six slots. Each half-rate DTC uses one time slot of each TDMA frame. During each DTC time slot, 324 bits are transmitted, of which the major portion, 260 bits, is due to the speech output of the codec, including bits due to error correction coding of the speech output, and the remaining bits are used for guard times and overhead signalling for purposes such as synchronization. It can be seen that the TDMA cellular system operates in a buffer-and-burst, or discontinuous-transmission, mode: each mobile station transmits (and receives) only during its assigned time slots. At full rate, for example, a mobile station might transmit during slot 1, receive during slot 2, idle during slot 3, transmit during slot 4, receive during slot 5, and idle during slot 6, and then repeat the cycle during succeeding TDMA frames. Therefore, the mobile station, which may be battery-powered, can be switched off, or sleep, to save power during the time slots when it is neither transmitting nor receiving. In addition to voice or traffic channels, cellular radio communication systems also provide paging/access, or control, channels for carrying call-setup messages between base stations and mobile stations. According to TIA/EIA/IS-54-B, for example, there are twenty-one dedicated analog control channels (ACCs), which have predetermined fixed frequencies for transmission and reception located near 800 MHz. Since these ACCs are always found at the same frequencies, they can be readily located and monitored by the mobile stations. For example, when in an idle state (i.e., switched on but not making or receiving a call), a mobile station in a TIA/EIA/IS-54-B system tunes to and then regularly monitors the strongest control channel (generally, the control channel of the cell in which the mobile station is located at that moment) and may receive or initiate a call through the corresponding base station. When moving between cells while in the idle state, the mobile station will eventually "lose" radio connection on the control channel of the "old" cell and tune to the control channel of the "new" cell. The initial tuning and subsequent re-tuning to control channels are both accomplished automatically by scanning all the available control channels at their known frequencies to find the "best" control channel. When a control channel with good reception quality is found, the mobile station remains tuned to this channel until the quality deteriorates again. In this way, mobile stations stay "in touch" with the system. While in the idle state, a mobile station must monitor the control channel for paging messages addressed to it. For example, when an ordinary telephone (land-line) subscriber calls a mobile subscriber, the call is directed from the public switched telephone network (PSTN) to a mobile switching center (MSC) that analyzes the dialed number. If the dialed number is validated, the MSC requests some or all of a number of radio base stations to page the called mobile station by transmitting over their respective control channels paging messages that contain the mobile identification number (MIN) of the called mobile station. Each idle mobile station receiving a paging message compares the received MIN with its own stored MIN. The mobile station with the matching stored MIN transmits a page response over the particular control channel to the base station, which forwards the page response to the MSC. Upon receiving the page response, the MSC selects an AVC or a DTC available to the base station that received the page response, switches on a corresponding radio transceiver in that base station, and causes that base station to send a message via the control channel to the called mobile station that instructs the called mobile station to tune to the selected voice or traffic channel. A through-connection for the call is established once the mobile station has tuned to the selected AVC or DTC. The performance of the system having ACCs that is specified by TIA/EIA/IS-54-B has been improved in a system having digital control channels (DCCHs) that is specified in TIA/EIA/IS-136, the disclosure of which is expressly incorporated here by reference. Using such DCCHs, each TIA/EIA/IS-54-B radio channel can carry DTCs only, DCCHs only, or a mixture of both DTCs and DCCHs. Within the TIA/EIA/IS-54-B framework, each radio carrier frequency can have up to three full-rate DTCs/DCCHs, or six half-rate DTCs/DCCHs, or any combination in between, for example, one full-rate and four half-rate DTCs/DCCs. In general, however, the transmission rate of the DCCH need not coincide with the half-rate and full-rate specified in TIA/EIA/IS-54-B, and the length of the DCC slots may not be uniform and may not coincide with the length of the DTC slots. The DCCH may be defined on a TIA/EIA/IS-54-B radio channel and may consist, for example, of every n-th slot in the stream of consecutive TDMA slots. In this case, the length of each DCCH slot may or may not be equal to 6.67 msec, which is the length of a DTC slot according to TIA/EIA/IS-54-B. Alternatively (and without limitation on other possible alternatives), these DCCH slots may be defined in other ways known to one skilled in the art. In cellular telephone systems, an air link protocol is required in order to allow a mobile station to communicate with the base stations and MSC. The communications link protocol is used to initiate and to receive cellular telephone calls. The communications link protocol is commonly referred to within the communications industry as a Layer 2 protocol, and its functionality includes the delimiting, or framing, of Layer 3 messages. These Layer 3 messages may be sent between communicating Layer 3 peer entities residing within mobile stations and cellular switching systems. The physical layer (Layer 1) defines the parameters of the physical communications channel, e.g., radio frequency spacing, modulation characteristics, etc. Layer 2 defines the techniques necessary for the accurate transmission of information within the constraints of the physical channel, e.g., error correction and detection, etc. Layer 3 defines the procedures for reception and processing of information transmitted over the physical channel. Communications between mobile stations and the cellular switching system (the base stations and the MSC) can be described in general with reference to FIGS. 1, 2(a), and 2(b). FIG. 1 schematically illustrates pluralities of Layer 3 messages 11, Layer 2 frames 13, and Layer 1 channel bursts, or time slots, 15. In FIG. 1, each group of channel bursts corresponding to each Layer 3 message may constitute a logical channel, and as described above, the channel bursts for a given Layer 3 message would usually not be consecutive slots on an TIA/EIA/136 carrier. On the other hand, the channel bursts could be consecutive; as soon as one time slot ends, the next time slot could begin. Each Layer 1 channel burst 15 contains a complete Layer 2 frame as well as other information such as, for example, error correction information and other overhead information used for Layer 1 operation. Each Layer 2 frame contains at least a portion of a Layer 3 message as well as overhead information used for Layer 2 operation. Although not indicated in FIG. 1, each Layer 3 message would include various information elements that can be considered the payload of the message, a header portion for identifying the respective message's type, and possibly padding. Each Layer 1 burst and each Layer 2 frame is divided into a plurality of different fields. In particular, a limited-length DATA field in each Layer 2 frame contains the Layer 3 message 11. Since Layer 3 messages have variable lengths depending upon the amount of information contained in the Layer 3 message, a plurality of Layer 2 frames may be needed for transmission of a single Layer 3 message. As a result, a plurality of Layer 1 channel bursts may also be needed to transmit the entire Layer 3 message as there is a one-to-one correspondence between channel bursts and Layer 2 frames. As noted above, when more than one channel burst is required to send a Layer 3 message, the several bursts are not usually consecutive bursts on the radio channel. Moreover, the several bursts are not even usually successive bursts devoted to the particular logical channel used for carrying the Layer 3 message. Since time is required to receive, process, and react to each received burst, the bursts required for transmission of a Layer 3 message are usually sent in a staggered format, as schematically illustrated in FIG. 2(a) and as described above in connection with the TIA/EIA/IS-136 standard. FIG. 2(a) shows a general example of a forward (or downlink) DCCH configured as a succession of time slots 1, 2, . . . , N . . . included in the consecutive time slots 1, 2, . . . sent on a carrier frequency. These DCCH slots may be defined on a radio channel such as that specified by TIA/EIA/IS-136, and may consist, as seen in FIG. 2(a) for example, of every n-th slot in a series of consecutive slots. Each DCCH slot has a duration that may or may not be 6.67 msec, which is the length of a DTC slot according to the TIA/EIA/IS-136 standard. As shown in FIG. 2(a), the DCCH slots may be organized into superframes (SF), and each superframe includes a number of logical channels that carry different kinds of information. One or more DCCH slots may be allocated to each logical channel in the superframe. The exemplary downlink superframe in FIG. 2(a) includes three logical channels: a broadcast control channel (BCCH) including six successive slots for overhead messages; a paging channel (PCH) including one slot for paging messages; and an access response channel (ARCH) including one slot for channel assignment and other messages. The remaining time slots in the exemplary superframe of FIG. 2(a) may be dedicated to other logical channels, such as additional paging channels PCH or other channels. Since the number of mobile stations is usually much greater than the number of slots in the superframe, each paging slot is used for paging several mobile stations that share some unique characteristic, e.g., the last digit of the MIN. FIG. 2(b) illustrates a preferred information format for the slots of a forward DCCH. The invention transmitted in each slot comprises a plurality of fields, and FIG. 2(b) indicates the number of bits in each field above that field. The bits sent in the SYNC field are used in a conventional way to help ensure accurate reception of the coded superframe phase (CSFP) and DATA fields. The SYNC field includes a predetermined bit pattern used by the base stations to find the start of the slot. The shared channel feedback (SCF) field is used to control a random access channel (RACH), which is used by the mobile to request access to the system. The CSFP field conveys a coded superframe phase value that enables the mobile stations to find the start of each superframe. This is just one example for the information format in the slots of the forward DCCH. For purposes of efficient sleep mode operation and fast cell selection, the BCCH may be divided into a number of sub-channels. A BCCH structure is known that allows the mobile station to read a minimum amount of information when it is switched on (when it locks onto a DCCH) before being able to access the system (place or receive a call). After being switched on, an idle mobile station needs to regularly monitor only its assigned PCH slots (usually one in each superframe); the mobile can sleep during other slots. The ratio of the mobile's time spent reading paging messages and its time spent asleep is controllable and represents a tradeoff between call-set-up delay and power consumption. Since each TDMA time slot has a certain fixed information carrying capacity, each burst typically carries only a portion of a Layer 3 message as noted above. In the uplink direction, multiple mobile stations attempt to communicate with the system on a contention basis, while multiple mobile stations listen for Layer 3 messages sent from the system in the downlink direction. In known systems, any given Layer 3 message must be carried using as many TDMA channel bursts as required to send the entire Layer 3 message. Digital control and traffic channels are desirable for reasons, such as supporting longer sleep periods for the mobile units, which results in longer battery life. Digital traffic channels and digital control channels have expanded functionality for optimizing system capacity and supporting hierarchical cell structures, i.e., structures of macrocells, microcells, picocells, etc. The term "macrocell" generally refers to a cell having a size comparable to the sizes of cells in a conventional cellular telephone system (e.g., a radius of at least about 1 kilometer), and the terms "microcell" and "picocell" generally refer to progressively smaller cells. For example, a microcell might cover a public indoor or outdoor area, e.g., a convention center or a busy street, and a picocell might cover an office corridor or a floor of a high-rise building. From a radio coverage perspective, macrocells, microcells, and picocells may be distinct from one another or may overlap one another to handle different traffic patterns or radio environments. FIG. 3 is an exemplary hierarchical, or multi-layered, cellular system. An umbrella macrocell 10 represented by a hexagonal shape makes up an overlying cellular structure. Each umbrella cell may contain an underlying microcell structure. The umbrella cell 10 includes microcell 20 represented by the area enclosed within the dotted line and microcell 30 represented by the area enclosed within the dashed line corresponding to areas along city streets, and picocells 40, 50, and 60, which cover individual floors of a building. The intersection of the two city streets covered by the microcells 20 and 30 may be an area of dense traffic concentration, and thus might represent a hot spot. FIG. 4 represents a block diagram of an exemplary cellular mobile radiotelephone system, including an exemplary base station 110 and mobile station 120. The base station includes a control and processing unit 130 which is connected to the MSC 140 which in turn is connected to the PSTN (not shown). General aspects of such cellular radiotelephone systems are known in the art, as described by U.S. Pat. No. 5,175,867 to Wejke et al., entitled "Neighbor-Assisted Handoff in a Cellular Communication System," which is incorporated in this application by reference. The base station 110 handles a plurality of voice channels through a voice channel transceiver 150, which is controlled by the control and processing unit 130. Also, each base station includes a control channel transceiver 160, which may be capable of handling more than one control channel. The control channel transceiver 160 is controlled by the control and processing unit 130. The control channel transceiver 160 broadcasts control information over the control channel of the base station or cell to mobiles locked to that control channel. It will be understood that the transceivers 150 and 160 can be implemented as a single device, like the voice and control transceiver 170, for use with DCCHs and DTCs that share the same radio carrier frequency. The mobile station 120 receives the information broadcast on a control channel at its voice and control channel transceiver 170. Then, the processing unit 180 evaluates the received control channel information, which includes the characteristics of cells that are candidates for the mobile station to lock on to, and determines on which cell the mobile should lock. Advantageously, the received control channel information not only includes absolute information concerning the cell with which it is associated, but also contains relative information concerning other cells proximate to the cell with which the control channel is associated, as described in U.S. Pat. No. 5,353,332 to Raith et al., entitled "Method and Apparatus for Communication Control in a Radiotelephone System," which is incorporated in this application by reference. To increase the user's "talk time", i.e., the battery life of the mobile station, a digital forward control channel (base station to mobile station) may be provided that can carry the types of messages specified for current analog forward control channels (FOCCs), but in a format which allows an idle mobile station to read overhead messages when locking onto the FOCC and thereafter only when the information has changed; the mobile sleeps at all other times. In such a system, some types of messages are broadcast by the base stations more frequently than other types, and mobile stations need not read every message broadcast. The systems specified by the TIA/EIA/IS-54-B and TIA/EIA/IS-136 standards are circuit-switched technology, which is a type of "connection-oriented" communication that establishes a physical call connection and maintains that connection for as long as the communicating end-systems have data to exchange. The direct connection of a circuit switch serves as an open pipeline, permitting the end-systems to use the circuit for whatever they deem appropriate. While circuit-switched data communication may be well suited to constant-bandwidth applications, it is relatively inefficient for low-bandwidth and "bursty" applications. Packet-switched technology, which may be connection-oriented (e.g., X.25) or "connectionless" (e.g., the Internet Protocol, "IP"), does not require the set-up and tear-down of a physical connection, which is in marked contrast to circuit-switched technology. This reduces the data latency and increases the efficiency of a channel in handling relatively short, bursty, or interactive transactions. A connectionless packet-switched network distributes the routing functions to multiple routing sites, thereby avoiding possible traffic bottlenecks that could occur when using a central switching hub. Data is "packetized" with the appropriate end-system addressing and then transmitted in independent units along the data path. Intermediate systems, sometimes called "routers", stationed between the communicating end-systems make decisions about the most appropriate route to take on a per packet basis. Routing decisions are based on a number of characteristics, including: least-cost route or cost metric; capacity of the link; number of packets waiting for transmission; security requirements for the link; and intermediate system (node) operational status. Packet transmission along a route that takes into consideration path metrics, as opposed to a single circuit set up, offers application and communications flexibility. It is also how most standard local area networks (LANs) and wide area networks (WANs) have evolved in the corporate environment. Packet switching is appropriate for data communications because many of the applications and devices used, such as keyboard terminals, are interactive and transmit data in bursts. Instead of a channel being idle while a user inputs more data into the terminal or pauses to think about a problem, packet switching interleaves multiple transmissions from several terminals onto the channel. Packet data provides more network robustness due to path independence and the routers' ability to select alternative paths in the event of network node failure. Packet switching, therefore, allows for more efficient use of the network lines. Packet technology offers the option of billing the end user based on amount of data transmitted instead of connection time. If the end user's application has been designed to make efficient use of the air link, then the number of packets transmitted will be minimal. If each individual user's traffic is held to a minimum, then the service provider has effectively increased network capacity. Packet networks are usually designed and based on industry-wide data standards such as the open system interface (OSI) model or the TCP/IP protocol stack. These standards have been developed, whether formally or de facto, for many years, and the applications that use these protocols are readily available. The main objective of standards-based networks is to achieve interconnectivity with other networks. The Internet is today's most obvious example of such a standards-based network pursuit of this goal. Packet networks, like the Internet or a corporate LAN, are integral parts of today's business and communications environments. As mobile computing becomes pervasive in these environments, wireless service providers such as those using TIA/EIA/IS-136 are best positioned to provide access to these networks. Nevertheless, the data services provided by or proposed for cellular systems are generally based on the circuit-switched mode of operation, using a dedicated radio channel for each active mobile user. A few exceptions to data services for cellular systems based on the circuit-switched mode of operation are described in the following documents, which include the packet data concepts. U.S. Pat. No. 4,887,265 and "Packet Switching in Digital Cellular Systems", Proc. 38th IEEE Vehicular Technology Conf., pp. 414-418 (June 1988) describe a cellular system providing shared packet data radio channels, each one capable of accommodating multiple data calls. A mobile station requesting packet data service is assigned to a particular packet data channel using essentially regular cellular signalling. The system may include packet access points (PAPS) for interfacing with packet data networks. Each packet data radio channel is connected to one particular PAP and is thus capable of multiplexing data calls associated with that PAP. Handovers are initiated by the system in a manner that is largely similar to the handover used in the same system for voice calls. A new type of handover is added for those situations when the capacity of a packet channel is insufficient. These documents are data-call oriented and based on using system-initiated handover in a similar way as for regular voice calls. Applying these principles for providing general purpose packet data services in a TDMA cellular system would result in spectrum-efficiency and performance disadvantages. U.S. Pat. No. 4,916,691 describes a new packet mode cellular radio system architecture and a new procedure for routing (voice and/or data) packets to a mobile station. Base stations, public switches via trunk interface units, and a cellular control unit are linked together via a WAN. The routing procedure is based on mobile-station-initiated handovers and on adding to the header of any packet transmitted from a mobile station (during a call) an identifier of the base station through which the packet passes. In case of an extended period of time between subsequent user information packets from a mobile station, the mobile station may transmit extra control packets for the purpose of conveying cell location information. The cellular control unit is primarily involved at call establishment, when it assigns to the call a call control number. It then notifies the mobile station of the call control number and the trunk interface unit of the call control number and the identifier of the initial base station. During a call, packets are then routed directly between the trunk interface unit and the currently serving base station. The system described in U.S. Pat. No. 4,916,691 is not directly related to the specific problems of providing packet data services in TDMA cellular systems. "Packet Radio in GSM", European Telecommunications Standards Institute (ETSI) T Doc SMG 4 58/93 (Feb. 12, 1993) and "A General Packet Radio Service Proposed for GSM" presented during a seminar entitled "GSM in a Future Competitive Environment", Helsinki, Finland (Oct. 13, 1993) outline a possible packet access protocol for voice and data in GSM. These documents directly relate to TDMA cellular systems, i.e., GSM, and although they outline a possible organization of an optimized shared packet data channel, they do not deal with the aspects of integrating packet data channels in a total system solution. "Packet Data over GSM Network", T Doc SMG 1 238/93, ETSI (Sep. 28, 1993) describes a concept of providing packet data services in GSM based on first using regular GSM signalling and authentication to establish a virtual channel between a packet mobile station and an "agent" handling access to packet data services. With regular signalling modified for fast channel setup and release, regular traffic channels are then used for packet transfer. This document directly relates to TDMA cellular systems, but since the concept is based on using a "fast switching" version of existing GSM traffic channels, it has disadvantages in terms of spectrum efficiency and packet transfer delays (especially for short messages) compared to a concept based on optimized shared packet data channels. Cellular Digital Packet Data (CDPD) System Specification, Release 1.0 (July 1993), the disclosure of which is expressly incorporated here by reference, describes a concept for providing packet data services that utilizes available radio channels on current Advanced Mobile Phone Service (AMPS) systems, i.e., the North American analog cellular system. CDPD is a comprehensive, open specification endorsed by a group of U.S. cellular operators. Items covered include external interfaces, air link interfaces, services, network architecture, network management, and administration. The specified CDPD system is to a large extent based on an infrastructure that is independent of the existing AMPS infrastructure. Commonalities with AMPS systems are limited to utilization of the same type of radio frequency channels and the same base station sites (the base station used by CDPD may be new and CDPD specific) and employment of a signalling interface for coordinating channel assignments between the two systems. Routing a packet to a mobile station is based on, first, routing the packet to a home network node (home Mobile Data Intermediate System, MD-IS) equipped with a home location register (HLR) based on the mobile station address; then, when necessary, routing the packet to a visited, serving MD-IS based on HLR information; and finally transferring the packet from the serving MD-IS via the current base station, based on the mobile station reporting its cell location to its serving MD-IS. Although the CDPD System Specification is not directly related to the specific problems of providing packet data services in TDMA cellular systems that are addressed by this application, the network aspects and concepts described in the CDPD System Specification can be used as a basis for the network aspects needed for an air link protocol in accordance with this invention. The CDPD network is designed to be an extension of existing data communications networks and the AMPS cellular network. Existing connectionless network protocols may be used to access the CDPD network. Since the network is always considered to be evolving, it uses an open network design that allows the addition of new network layer protocols when appropriate. The CDPD network services and protocols are limited to the Network Layer of the OSI model and below. Doing so allows upper-layer protocols and applications development without changing the underlying CDPD network. From the mobile subscriber's perspective, the CDPD network is a wireless mobile extension of traditional networks, both data and voice. By using a CDPD service provider network's service, the subscriber is able seamlessly to access data applications, many of which may reside on traditional data networks. The CDPD system may be viewed as two interrelated service sets: CDPD network support services and CDPD network services. CDPD network support services perform duties necessary to maintain and administer the CDPD network. These services are: accounting server; network management system; message transfer server; and authentication server. These services are defined to permit interoperability among service providers. As the CDPD network evolves technically beyond its original AMPS infrastructure, it is anticipated that the support services shall remain unchanged. The functions of network support services are necessary for any mobile network and are independent of radio frequency (RF) technology. CDPD network services are data transfer services that allow subscribers to communicate with data applications. Additionally, one or both ends of the data communication may be mobile. To summarize, there is a need for a system providing general purpose packet data services in D-AMPS cellular systems, based on providing shared packet-data channels optimized for packet data. This application is directed to systems and methods that provide the combined advantages of a connection-oriented network like that specified by the TIA/EIA/IS-136 standard and a connectionless, packet data network. Furthermore, this invention is directed to accessing the CDPD network, for example, by existing connectionless network protocols with low complexity and high throughput. SUMMARY In accordance with one aspect of the invention, there is provided a method of supporting a plurality of mobile station operation modes in a wireless communication system which are selectable by user or other external control. Presently, communication protocols exist for supporting end user equipment which operates only in a single mode of operation. However, it is desirable to combine protocols from various technologies to form end user equipment which operates in multiple modes of operation. Thereby, the present method allows the mobile station to operate in a multi-mode environment where a user or external device can invoke one or more operational modes. BRIEF DESCRIPTION OF THE DRAWINGS The features and advantages of Applicants' invention will be understood by reading this description in conjunction with the drawings in which: FIG. 1 schematically illustrates pluralities of Layer 3 messages, Layer 2 frames, and Layer 1 channel bursts, or time slots; FIG. 2(a) shows a forward DCCH configured as a succession of time slots included in the consecutive time slots sent on a carrier frequency; FIG. 2(b) shows an example of an IS-136 DCCH field slot format; FIG. 3 illustrates an exemplary hierarchical, or multi-layered, cellular system; FIG. 4 is a block diagram of an exemplary cellular mobile radiotelephone system, including an exemplary base station and mobile station; FIGS. 5(a)-5(e) illustrate end-user equipment providing packet data functionality; FIG. 6 illustrates one example of a possible mapping sequence between various layers in a radiocommunication system; FIGS. 7(a)-7(e) illustrate examples of mobile station functional modes; and FIG. 7(f) illustrates one example of a telemetric device and a mobile station having a display device. DETAILED DESCRIPTION As described above, there are numerous technologies which support wireless data communication, including packet data. Of particular interest are D-AMPS (TIA/EIA/IS-136) and CDPD. By combining protocols from these two existing technologies with the functionality described in this application, new forms of end-user equipment can be identified. FIGS. 5(a)-5(e) illustrate examples of how the functionality of this application ("D-AMPS Packet Data") can be combined with other technologies into new end-user equipment. This invention is directed to implementing protocols and procedures for connectionless communication between the mobile station and the base station. In particular, the invention is directed to an air interface protocol and the associated mobile station procedures required for packet data that are based on IS-136. The protocol and procedures for one aspect of this invention resemble the digital control channel (DCCH) operation of IS-136 because IS-136 was designed to provide connectionless transmission of a point-to-point short message service on the DCCH. The IS-136 protocol and procedures have been expanded to support packet-oriented services in embodiments of Applicants' invention. More generally, the invention is directed to communication between a base station and network entities using any standardized or proprietary packet network or using a connection oriented protocol because no assumptions have been made about the network. The network aspect of the CDPD specification is one example that can be used in implementing this invention. In order to maximize the flexibility of performance characteristics and be able to tailor terminal implementation for specific applications in specific embodiments of the invention, several bandwidth allocations are provided. One such bandwidth allocation is hosted PDCH, which is an added logical subchannel on the IS-136 digital control channel. The hosted PDCH allows a minimal implementation effort but provides limited throughput rate. Three other bandwidth allocations provided on the dedicated PDCH are full-rate PDCH, double-rate PDCH and triple-rate PDCH. A PDCH can be mixed with IS-136 DCCHs and DTCs on the same carrier up to the rate limit corresponding to three full rate channels. The interested reader is directed to U.S. patent application Ser. No. 08/544,493, now U.S. Pat. No. 5,907,555, entitled "A Method for Compensating Time Dispersion in a Communication System," to Raith et al., filed on Oct. 18, 1995 and U.S. patent application Ser. No. 08/544,490, now U.S. Pat. No. 5,729,531, entitled "Bandwidth Allocation" to Raith et al., filed on Oct. 18, 1995, the disclosure of both applications being expressly incorporated here by reference. As illustrated in FIGS. 5(a) and 5(b), existing terminals may operate in either only the CDPD mode (FIG. 5(a)) or only the D-AMPS mode (FIG. 5(b)). However, the terminal may selectively operate in one or more of multiple modes as illustrated in FIGS. 5(c), 5(d), and 5(e) by implementing the protocol and procedures of this invention. For example, the terminal may support D-AMPS packet data only as illustrated in FIG. 5(c), D-AMPS (i.e., IS-136 voice and data) and D-AMPS packet data and CDPD as illustrated in FIG. 5(d) and D-AMPS and D-AMPS packet data as illustrated in FIG. 5(e). Additionally, the set of specifications also includes support for the asynchronous data, Group 3 facsimile (IS-130 and IS-135) and short message services which are not illustrated in FIGS. 5(a)-5(e). As a result, this invention combined with other technologies provide new end user equipment. The utility of equipment conforming to the invention can be viewed from a variety of perspectives. From the D-AMPs cellular/PCS operator perspective, the equipment can be efficiently deployed in both D-AMPs 800 MHz and PCS 1900 MHz. This mode of operation has channel-by-channel upgrade with no frequency guard band needed, a common packet data/D-AMPS radio resource management, PDCH bandwidth allocation on demand, and full flexibility in allocating PDCH among frequencies and time slots. In this mode of operation, no geographic guard zones are needed and an existing frequency plan can be maintained. Thereby, the cellular and packet data networks have a greater availability and are more seamless through intersystem paging. Also, a higher bandwidth efficiency (throughput/bandwidth) is provided than in the CDPD air interface and the existing CDPD infrastructure may be retained. From the perspective of an AMPS cellular operator, if DCCH functionality is provided, the same benefits as for a D-AMPS operator can be achieved by implementing this invention. From the perspective of the D-AMPS mobile station manufacturer, this invention has no RF circuit impact, and the hosted PDCH operation does not require new physical layers or Layer 2 development. Furthermore, the dedicated PDCH provides for higher throughput than the CDPD air interface and requires a minimum development effort regarding hardware. Also, an enhanced sleep mode is provided which has less battery drain than CDPD; improved efficiency of broadcast and simulcast transmission is provided; and a seamless cellular/packet data service is achieved. From the perspective of the D-AMPs base station manufacturer, no impact on the RF circuit, combining of circuits and antenna configuration occurs by implementing this invention. Also, the hosted PDCH operation does not require new physical layers or Layer 2 development and the dedicated PDCH requires a minimum development effort using IS-136 as a basis. From the perspective of the packet data network equipment manufacturer, the CDPD backbone and CDPD applications are not impacted by implementing this invention. From the perspective of the CDPD mobile station manufacturer, all higher layer protocols can be reused when implementing this invention. The protocol and procedures for connectionless communication between mobile stations and base stations in accordance with this invention are directed to maximizing performance characteristics. Other desirable expansions of functionality by this invention include introducing PDCH paging areas and registration, as per IS-136 for example, providing the option to send Layer 3 messages defined for connectionless communication on a connection-oriented DTC, providing for IS-136 paging indicators while on the PDCH and providing for dedicated PDCH notification while on a DTC. One possible set of specific protocol and procedures for enhancing aspects of various connectionless communication between mobile stations and base stations is discussed below. To aid in understanding, one exemplary mapping sequence is illustrated in FIG. 6. Beginning with a CDPD mobile data link protocol (MDLP) frame, a Layer 3 message, including a protocol discriminator (PD) and message type (MT) indicator, is mapped into several Layer 2 frames. The Layer 2 frame is further mapped onto an FPDCH time slot. Lastly, the mapping of FPDCH time slots onto a superframe is illustrated. The length of the forward PDCH (FPDCH) time slots and reverse PDCH (RPDCH) bursts are fixed; although there may be three forms of RPDCH bursts which have different fixed lengths. The FPDCH slot and the full-rate PDCH are assumed to be on the physical layer in FIG. 6. This description assumes the TDMA frame structure is that of the IS-136 DCCH and DTC. In the interest of maximal throughput when a multi-rate channel is used (double-rate PDCH and triple-rate PDCH), an additional FPDCH slot format is specified. Existing technologies such as D-AMPS and CDPD may be combined to provide multiple mode terminal functionality as illustrated in FIGS. 5(c), 5(d), and 5(e). The functionality for combining D-AMPS and CDPD technologies from a terminal and end user point-of-view will be described with reference to FIGS. 7(a), 7(b), 7(c), 7(d), and 7(e). In each of these figures, the selection of the mode of operation may be controlled by the user at every power-on event, by a default mode that has been stored in the terminal by the user or by an external device such as a computer or remotely monitored apparatus. FIG. 7(a) illustrates selecting only one of the plural modes of operation. For example, the user may want to activate the D-AMPS mode only, whereby the mobile station does not register itself on the PDCH system. The base station, MSC and interworking function (BMI) would then not be informed about the packet data capability of the mobile station. Alternatively, the packet-only mode may be activated by the user. Analogously, the mobile station need not then register with the IS-136 system. FIG. 7(a) illustrates the functional group selection which may be made by the user, by the stored default mode or by another external device which is linked to the radio terminal. FIG. 7(b) illustrates the selection of activating both D-AMPS and PDCH modes of operation. As illustrated by step 1 of FIG. 7(b), the mobile station finds a DCCH and reads the BCCH to find a pointer to a corresponding beacon PDCH. The beacon PDCH (the carrier frequency of one PDCH) is provided if the DCCH indicates support of one or more dedicated PDCHs. The mobile station registers itself on the beacon PDCH and may be assigned another dedicated PDCH by the base station, MSC and Interworking function (BMI) response. Once the mobile station is locked to its assigned PDCH, the mobile station enters an active mode and registers itself as represented by step 2. Once the PDCH registration is successfully completed or an irrecoverable error condition is detected, the mobile station returns to camp on the initial DCCH as represented at step 3. Accordingly, FIG. 7(b) illustrates the possibility of operating the mobile station as a voice and packet terminal by activating both D-AMPS and PDCH modes of operation in this example. FIG. 7(c) illustrates the mobile station activated as a packet only terminal. FIG. 7(c) illustrates one example where the PDCH mode of operation is only activated by the mobile station first finding a DCCH and reading the BCCH to find the pointer to the beacon PDCH as represented by step 1 of FIG. 7(c). The mobile station does not register itself on the DCCH at this time as it did in the previous example. For additional material related to beacon PDCH's, the interested reader should refer to U.S. patent application Ser. No. 08/544,488, now U.S. Pat. No. 5,768,267, entitled "A Method for System Registration and Cell Reselection" to Raith et al., which application was filed on Oct. 18, 1995 and which disclosure is expressly incorporated here by reference. Once the mobile station is locked to the beacon PDCH, the mobile station enters a CDPD active mode and registers itself as represented by step 2. The mobile station may be redirected to a different PDCH as a result of its BMI response to its registration. The mobile station stays in the active mode on the indicated PDCH until an active timer has expired as represented by step 3. The mobile station then enters a passive mode as represented by step 4. In this way, the mobile station is activated as a packet-only terminal at registration. For a complete discussion of the active timer described in the foregoing example and the passive time discussed in the following example, the interested reader is directed to U.S. patent application Ser. No. 08/544,838, now U.S. Pat. No. 5,806,007, entitled "Activity Control for a Mobile Station In a Wireless Communication System;" to Raith et al., which application is expressly incorporated here by reference. In FIG. 7(d), the mobile station is activated (i.e., has registered, as discussed above with respect to FIG. 7(a) in both the D-AMPS and PDCH mode of operation where the default mode of operation is D-AMPS. FIG. 7(d) is directed to a sequence of events which includes both a PDCH and D-AMPS page. When the mobile station is in the IS-136 sleep mode and a page message is received, which indicates a terminating PDCH transaction, (i.e., packet data is to be sent to the mobile) the mobile station moves to its previously assigned PDCH and enters an active mode as represented by step 1 of FIG. 7(d). After the terminating PDCH transaction is completed, and an activity timer has expired, the mobile station enters a CDPD passive mode as represented at step 2. After a second timer expires while in the passive mode, the mobile station returns to the initial DCCH as represented by step 3. When the mobile station is in an IS-136 sleep mode and a voice or IS-136 page is received, the mobile station is assigned a traffic channel for a voice call as represented by step 4. After completion of the voice call, the mobile station returns to the IS-136 sleep mode as represented by step 5. Accordingly, these functions allow the mobile station to be paged as either a voice or a packet data terminal. An example of a mobile station paged as a packet-only terminal is illustrated in FIG. 7(e). As represented at step 1 of FIG. 7(e), a page message is received indicating a terminating PDCH transaction. After the terminating PDCH transaction is completed, and the active timer expires without receiving additional packet data, the mobile station enters a passive mode as represented by step 2. The IS-136 active mode is not needed for a packet data-only terminal and this mode is unused as indicated in FIG. 7(e). The capability to read the BCCH on IS-136 is still required for a packet data only terminal and is indicated as such in FIG. 7(e) by the broken "X" across the IS-136 state. For example, the overhead information provided on the DCCH may be used as described in U.S. patent application Ser. No. 08/544,839, now U.S. Pat. No. 6,016,428, entitled "Registration Control of Mobile Stations in a Wireless Communication System," to Diachina et al., filed on Oct. 18, 1995, the disclosure of which is expressly incorporated here by reference. Accordingly, the mobile station functions as a packet data-only terminal. To facilitate the user control for the multiple modes of operation by the mobile station in this invention, user interaction techniques may be provided to control the multiple modes of operation. In one example of a user interaction technique, the user may acquire the availability of services and attributes of the mobile station by a known display 181 of the mobile station. The services and attributes, and especially the transmission rate, may be presented to the user on the display in any conventional display form, such as with icons, symbols, or text. Thereafter, the user may change the mode of operation for any amount of time and may also change the default mode of operation permanently. Accordingly, a large amount of control may be provided to the user for operating the mobile stations in multiple modes. The control for the multiple modes of operation by the mobile station in this invention may alternately be controlled by telemetry. In one example of a telemetric technique, data may be collected remotely from a computer 182 by a mobile station. In this case, the mobile station may send information on its services and attributes to the computer. Then, the computer may select the desired mode of operation based on the data to be collected and sent to the mobile station. The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

A method and device are provided for of supporting a plurality of mobile station operation modes in a wireless communication system by user control. Presently, communication protocols exist for supporting end user equipment which operates in a single mode of operation. However, it is desirable to combine protocols from various technologies to form end user equipment which operates in multiple modes of operation. Thereby, the present method allows the mobile station to operate in a multi-mode environment where a user can invoke a certain mode.

BACKGROUND OF THE INVENTION Machine tools utilizing a rotating workpiece or a rotating spindle are often capable of permitting sequential tool operation on the workpiece. For instance, where the workpiece is rotating such as in lathes, turret lathes and chucking machines, a variety of tools such as boring tools, centers, drills and reamers may be mounted upon an indexable tool holder, such as a turret, for sequential engagement with the workpiece. In this manner a plurality of machining operations may be accomplished without tranfer of the workpiece to another station or rotating chuck or spindle, but the nature of the machining operations are limited. Machine tools utilizing rotating tools such as drills and boring bits, may be mounted upon rotatable spindles of the axially translatable type. Such tools normally require that the workpiece be retrieved from a supply, chucked into the workpiece holder, machined by the tools, unchucked, and placed in a bulk container for transfer to the next machine tool. Such extensive multiple handling of the workpiece is expensive and time consuming, and makes it difficult to insure high accuracy and quality. Conventional machine tools do not permit the ready machining of opposite sides of a workpiece. For instance, workpieces such as hubs, blanks and gears often require turning and drilling operations on opposite sides thereof, and such operations require that the workpiece be chucked, machined, unchucked and then transported to another machine wherein the workpiece opposite side is chucked permitting machining of the side not previously accessible. The operations on opposite sides of the part have required two separate machines and two chuckings. It is an object of the invention to provide a machine tool of the automated type wherein the workpiece is sequentially transferred from one work station to another, each station utilizing a linearly displaceable rotating work-holding spindle wherein sequential operations may be automatically achieved upon a common workpiece. Another object of the invention is to provide a machine tool having a base and a transfer region defined thereon wherein workpieces are sequentially transferred between adjacent aligned rotating spindles permitting sequential secondary operations to be automatically performed on the workpiece. A further object of the invention is to provide a machine tool of the multiple spindle type wherein the base of the machine tool includes a central region and lateral sides disposed on opposite sides of the transfer central region. Tools located on opposite sides of the central region permit the workpiece to be automatically sequentially machined on opposite sides thereby minimizing handling and material flow problems. In the practice of the invention, a machine tool includes a heavy base having a central region and lateral sides located on opposite sides of the central region. In most cases, the base will be of an elongated configuration, and preferably, the base includes a plurality of laterally extending portions having a length perpendicularly disposed to the length of the central region. A plurality of work-holding spindles are mounted upon the base lateral sides, a single spindle usually being located upon each lateral portion, and preferably, spindles are located upon each base lateral side with respect to the central region. The spindles consist of elongated tubular heads mounted to be displaceable in their longitudinal direction, and each head usually includes a rotating work-holding spindle powered by an electric motor. However, non-rotating spindles may also be used at selected locations. Longitudinal displacement of the spindles is provided by a linear actuator, such as a threaded shaft or rod rotated by an electric motor. Work-holding means are mounted upon one end of the spindle, while torque transmitting means are defined upon the other spindle end in operative engagement with the spindle drive motor. The heads move in a direction substantially perpendicular to the length of the machine tool base central region, and work transfer apparatus is mounted upon the base central region for sequentially transferring workpieces between adjacent spindles. Preferably, the transfer means includes a plurality of work-holding blocks reciprocal between alignment with adjacent spindles in the direction of the central region length. As the spindles are mounted upon opposite sides of the workpiece transfer apparatus, the workpieces may be machined upon opposite sides by tools located adjacent the spindles as they are transferred between adjacent spindles, and the workpiece is sequentially transferred along the length of the machine tool central region to complete the desired operations. The work transfer apparatus includes an elongated beam suspended above the base central region, and the workpiece blocks suspend below this beam whereby the blocks may be readily aligned with the spindles. Reciprocal motor means, such as of the hydraulic or screw actuator type, are used to reciprocate the beam and workpiece holders. The apparatus of the invention permits a series of machining operations to be produced on a workpiece, the operation of the machine tool is fully automated, and the concise configuration of the machine tool and the rapid sequential machining operations permits relatively complex machining to be rapidly produced. BRIEF DESCRIPTION OF THE DRAWINGS The aforementioned objects and advantages of the invention will be appreciated from the following description and accompanying drawings wherein: FIG. 1 is a perspective view of a machine tool in accord with the invention, FIG. 2 is a plan view of the machine tool of FIG. 1, FIG. 3 is an elevational, partially sectional view of a typical spindle assembly utilized with the machine tool of the invention, and FIG. 4 is an elevational, sectional view as taken along Section IV--IV of FIG. 3. DESCRIPTION OF THE PREFERRED EMBODIMENT The overall arrangement of a machine tool in accord with the concept of the invention will be appreciated from FIGS. 1 and 2. The machine tool includes a base frame generally indicated at 10 which is of an elongated configuration as appreciated from FIG. 2, and includes a central region portion 12 of a rectangular configuration and lateral portions 14 are disposed upon opposite sides of the central region. The base is preferably formed of heavy fabricated or cast components, as is common in the machine tool art, and the frame may include access openings and the like for chip removal as is common. The frame lateral portions 14 are each of a generally rectangular configuration having a length perpendicularly disposed to the length of the central region 12, and the location of the lateral portions with respect to the length of the central region is determined by the operations that are to be performed on the machine tool, and the number of work-holding spindles to be located upon each side of the central region. Each frame lateral portion 14 serves as the support for a work-holding spindle assembly 16. Basically, each spindle assembly includes a rotating spindle having a workpiece holder located upon the inner end, and a spindle drive is associated with the outer end. Means are provided for axially translating the rotating spindle to feed the spindle into the transfer apparatus and provide the necessary workpiece pickup and movement. It will be appreciated that the specific arrangement of the spindle may take various forms. For instance, the location of the spindle electric drive motor may be above or below the spindle, and likewise, the means for translating the spindle may be located above or below the spindle axis. FIGS. 3 and 4 illustrate a typical spindle assembly, and for purpose of illustration, the arrangement is one wherein the spindle linear actuator is located below the spindle, and the drive motor for the spindle is located above the spindle axis. Each frame lateral portion 14, at its upper region, includes a guideway system which supports an elongated head 18. As will be appreciated from FIG. 3, the guideway system includes anti-friction bearings 20 which support the rectangular head 18 for linear displacement along its length. Of course, the head bearing system must very accurately support the head throughout its axial movement, and the linear actuator for axially translating the head is described below. Internally, the head 18 supports the rotating shaft 22 and its portion 23 constituting the spindle. The spindle 22 is rotatably supported within the head 18 upon axially spaced bearings 24 wherein the spindle accurately rotates within the head and is axially displaceable therewith. The outer end of the spindle includes a drive pulley 26 keyed thereto which is belted to an electric drive motor 28, located within the motor housing 30, FIG. 1. The inner end of the spindle 22 includes work-holding and chucking structure 32 conforming to the workpiece which may be of a conventional configuration and forms no part of the present invention. The work-holding apparatus is automatically operable by electric air or hydraulic actuators, not shown, as is well known in the work-holding art. Linear displacement of head 18 and advancement of the spindle 22, is achieved by a linear actuator. Such an actuator could be of the hydraulic or electric type, and in the disclosed embodiment comprises an electrically driven threaded shaft. As will be appreciated from FIG. 3, a threaded shaft 34 is rotatably mounted within bearing housings 36 fixed upon the guide structure for the head 18. The shaft 34 is restrained against axial thrust, and the head guide includes a slot 38 thorugh which the nut block 40 extends which is attached to the head 18. The nut block 40 includes a ball-nut 42 containing movable balls engaging the complementary threads or grooves of the threaded shaft 34 wherein a low friction ball-nut and screw arrangement of the known type is produced. Rotation of the shaft 34 is through the variable speed electric motor 44 and a step-down transmission 46 wherein selective rotation of the shaft 34 in either direction is produced and shaft rotation axially displaces the head 18 and spindle 22 during rapid and slow traverse, extended and retracted cycles. As will be appreciated from FIGS. 1 and 2, a plurality of base lateral portions 14 and spindle assemblies are utilized with a machine tool in accord with the invention, the number being determined by the types of operations that are to be performed by the machine. Usually, spindle assemblies 16 will be located upon opposite sides of the frame central region 12, and such location of the spindles permits the workpiece to be approached from opposite sides permitting machining of the workpiece on both sides or opposite ends. Movement of the workpiece from one workpiece spindle to another is achieved by transfer apparatus 48 located on the base central region 12. While the transfer mechanism could take a variety of forms, a preferred embodiment is that illustrated wherein the transfer apparatus is elevated with respect to the central region. In this form, the transfer apparatus includes an elongated beam 50, broken for purpose of illustration in FIG. 1, supported above the central region upon guide columns 52 attached to the central region. A plurality of workpiece carriers 54 depend from below the beam 50 and move with the beam. The beam 50 is slidably supported on the columns 52 by bearings 55 and is longitudinally reciprocal by motor and drive means 56 under an automatic control 57. The motor and drive 56 may be hydraulic, air or electrically operated. Each workpiece carrier 54 is provided with chucking structure 58 which may be of a conventional form designed to conform to the workpiece for grasping the workpiece and holding the same during the transfer cycle. After being worked upon at each spindle location, the workpiece is transferred to an aligned carrier 54 and the beam 50 "shifts" along its length which moves the carrier 54 for alignment with the adjacent spindle assembly 16 thereby transferring the workpiece to the next spindle. The beam and workpiece carriers are returned to alignment after machining with the spindle with which they were previously aligned and are then ready to accept the next workpiece therefrom. Thus, it will be appreciated that it is only necessary for the beam workpiece carriers to shift a distance equal to the separation of adjacent spindle assemblies between cycles. The "first" workpiece carrier 54 on the beam 50 will receive the workpiece from automatic or manual loading means, not shown, and the "last" workpiece carrier on the beam will transfer the completed workpiece to a position accessible to automatic or manual workpiece transfer apparatus. As best appreciated from FIGS. 1 and 2, a plurality of tool systems 60 are mounted upon lateral portions 14 adjacent the central region 12 for machining the workpiece while it is held by the adjacent spindle. The tool systems 60 include a variety of conventional turning and boring tools, drills, taps, reamers and the like may be mounted upon the central region 12 upon slides 62 and operated by motors 64 to permit secondary operations at each tool spindle location of the type desired. In operation, the workpieces within workpiece carriers 54 will be aligned with a spindle assembly 16. Energizing of the motor 44 will axially translate the head 18 toward the aligned carrier 54 permitting the chuck 32 to engage the workpiece, and firmly grasp the workpiece. Of course, at such time the carrier chuck 58 releases the piece to be machined. The motor 44 is then reversed to retract the head 18 and spindle 22, and this retraction is sufficient to align the chucked workpiece with the tool system 60 associated with that particular spindle assembly. Assuming that the workpiece is to be rotated during machining by the associated tool system 60, the associated motor 28 is energized to rotate the spindle 22 and chucked workpiece, and the associated tools 60 are automatically translated upon their slide 62 to produce the desired machining. After machining is completed, the tools 60 are withdrawn from the workpiece, the motor 44 is energized to extend the head 18 and place the workpiece into an aligned workpiece carrier 54 which has been brought into alignment with the spindle assembly after transferring the workpiece thereto initially. As previously mentioned, the fact that spindle assemblies 16 are mounted upon opposite sides of the central region 12 permits the workpiece to be machined on opposite sides without reversing the workpiece. Thus, workpiece handling is simplified without a sacrifice in accuracy. Minimizing the number of chucking operations of the workpiece contributes to the accuracy of the machining and by locating spindles upon opposite sides of the central region, high accuracies on both sides of the workpiece may be readily achieved. It is to be understood that with some types of machine operations, such a lateral drilling, boring, broaching, tapping, etc., the workpiece must be held stationary, and in such instances the spindle shaft 22 will not be rotated by motor 28, but will be locked against rotation. The head 18 and spindle 22 will be axially translated toward and from the aligned work carrier 54 to pick up the workpiece and draw it back into position for alignment with the associated tool system 60 and will return the workpiece to a carrier 54 after machining, all without spindle rotation. Control apparatus, such as housed in control box 57, is used to automatically sequence the operations and functions of the machine tool in accord with the invention, and as conventional control apparatus may be used, the same does not form a part of the present invention. Such control apparatus uses conventional limit switches, position sensors and the like commonly used in the machine tool art to control rapid and slow traverses, tool feeds, retraction cycles, and the like. Likewise, the operation of the movement of the beam 50 and workpiece carriers 54 is fully automated and coordinated with the spindle operation so that sequential movement of the workpiece from spindle to spindle is automatically and efficiently achieved. A machine tool in accord with the invention is capable of performing a series of machine operations on a workpiece in an automated manner wherein high production and low cost may be achieved in conjunction with superior quality and accuracy. It is appreciated that various modifications to the inventive concepts may be apparent to those skilled in the art without departing from the spirit and scope of the invention.

The invention pertains to a multiple spindle machine tool wherein a plurality of substantially parallel spindles transversely disposed to a workpiece transfer path permit sequential operations upon a workpiece transferred from spindle to spindle. Spindles may be mounted upon opposite sides of the transfer path permitting machining on opposite sides of a workpiece, and the machine tool permits successive operations to be performed sequentially, rapidly and economically.

The present invention relates to stable alcohol-containing, cream-based beverages. For purposes of the present application, the term "cream-based" includes a variety of dairy products broadly, including low-fat milk, milk, cream, half-and-half, and heavy cream. Broadly, any composition having more than 2% butterfat plus milk solids is within the scope of the term "cream-based", for purposes of the present application, although the present invention is particularly useful with heavy cream-based beverages which also contain alcohol. Heavy cream has about 40% butterfat. Also for purposes of the present application, the term "stable" refers to emulsion stability against breaking of the emulsion. Products prepared according to the present invention have an emulsion shelf stability for up to eighteen months or longer under normal storage conditions (room temperature storage). BACKGROUND OF THE PRESENT INVENTION It is well known to prepare alcoholic drinks using an alcoholic beverage or liqueur and adding milk or cream to it. Typical such drinks are milk punch, an Alexander, Pink Squirrel, Golden Cadillac, Irish Alexander, Amareto Cream, and Grasshopper. These drinks are usually prepared at home or at a bar for immediate consumption. Thorough mixing is accomplished by shaking the drink in a shaker, but if the drink is allowed to stand for a period of time, for instance one half hour, separation is likely to occur, developing separate fat and water phases, rendering the drink impalatable. Cream or milk-based, alcohol-containing drinks are becoming more popular, cream or milk by many being considered a restorer of good health. It would be convenient for consumers of such drinks to be able to purchase them in a premixed, packaged, stable emulsion form. Because of the presence of the alcohol and a large amount of sugar, even refrigeration may not be necessary to prevent spoilage. The availability of premixed, purchasable cream-based drinks is particularly desirable where such drinks have to be made in relatively large quantities, for instance at parties. Also, many of such cream-based alcohol-containing drinks are somewhat complicated to make and require a fair amount of time, which the host may not have. Some liquor stores offer bottled eggnog complete with liquor, the liquor preventing non-alcoholic ingredients in the eggnog from spoiling. The emulsion stability of eggnog emulsions is accomplished by the presence of the eggs, and is due in part to the high viscosity of the emulsions. There are also on the market packaged, alcohol-containing drinks made using non-dairy creamers. Non-dairy creamers are engineered food products, a typical such creamer containing a vegetable fat, a sweetening agent such as corn syrup solids, a protein such as sodium casinate, an emulsifier such as a mono- diglyceride, and a gum stabilizer, all in predetermined proportions. All of the ingredients are relatively pure in composition and their properties are well known, alone and in the combination. It is thus possible to predict the proportions necessary and use of whatever additional ingredients are necessary to make an alcohol-containing such creamer shelf stable. There is also on the market a product known as Bailey's Irish Cream, prepared from heavy cream, alcohol, sugar and coffee flavor. Aside from the above ingredients, the composition is secret and it is not known how shelf stability of the product is obtained. U.S. Pat. No. 3,486,906 to Todd, Jr., describes the use of non-ionic emulsifiers such as polyoxyethylene ethers of mixed partial oleic esters of sorbitol anhydrides, including polysorbate 80 and the like, mixed with a flavoring ingredient and added to beer. However, the patent points out that such emulsifiers were found to be not stable in beer and soon produced a highly unpalatable flavor. U.S. Pat. No. 4,093,750 describes the use of polyglycerol esters in citrus flavored beverages, replacing brominated oils or gum acacia for emulsion stability, and also to provide a cloud to give the drinks a desirable appearance. There is no reference in this patent to the use of these agents in alcohol-containing beverages. BRIEF DESCRIPTION OF THE PRESENT INVENTION The present invention resides in a homogenized cream/alcohol-containing beverage comprising cream or milk and alcohol in drink preparation amounts, and a high HLB emulsifier selected from the group consisting of high HLB polyglycerol esters of fatty acids, ethoxylated fatty acid esters; and sugar esters, each in an emulsifying amount. The cream (or milk) and alcohol are present in major amounts, as distinguished from beverages containing flavor compositions, e.g., essential oils, where a small amount of alcohol carrier may be employed for such compositions. Natural cream and milk emulsions are very complicated. There are no pure systems in the compositions. Even tap water, which may be used in making the emulsion, contains certain salts which will affect emulsion stability. The proteins which are present, other salts, sugars, flavors and colors, and the emulsion pH, all will have an effect on the emulsion stability. Further, concentrations will vary from batch to batch because of the use of natural cream or milk. These complications are further compounded by the presence of the alcohol which is known to break or have an adverse effect on fat/water emulsions. Thus, it was a surprising and fortuitous discovery to find a limited group of emulsifiers capable of stabilizing such alcohol/cream or milk beverages for prolonged periods of time. By alcohol, it is meant ethyl alcohol, the traditional alcohol employed in alcoholic beverages. A typical beverage within the scope of the present invention is one that is 34 proof, is homogenized and contains about 17% alcohol, about 14% fat (from heavy cream), plus flavorings and colorants in addition to an emulsifying amount of an emulsifier selected from the group stated above. A particularly preferred emulsifier is octaglycerol monostearate marketed by SCM Corporation under the trademark "Santone 8-1-S". It was found that this emulsifier, of the many investigated, was by far the best in stabilizing, for many months, a cream-based, alcohol-containing beverage, the cream being 40% butterfat heavy cream, against detectable phase separation. Even shaking, after months of storage, was not necessary prior to consumption. DETAILED DESCRIPTION OF THE INVENTION Whereas a large number of emulsifiers are available on the market today and are approved for food uses, only a limited number of emulsifiers are operable in the present invention. There is no particular pattern as to which emulsifiers are operable and which are not, except that those that are operable have high HLB values (more than about 10), preferably about 10 to about 16. The class of ethoxylated fatty acid esters useful in the present invention are the ethoxylated fatty acid esters of glycerol, hexitol, hexitan and isohexide, as well as the fatty acid esters of ethoxylated glycerol, hexitol, hexitan and isohexide. Sorbitol is a typical hexitol. One specific class of such compounds for use in the beverage of the present invention are the ethoxylated mono- diglycerides, which are the polyethoxylated fatty acid esters of glycerol, and may be conventionally described as a mixture of stearate, palmitate, and lesser amounts of myristate partial esters of glycerin condensed with about 18 to 22 moles, preferably about 20 moles, of ethylene oxide per mole of alpha-monoglyceride reaction mixture such as set forth in The Food Codex and FDA Regulations, 21 CFR 121.1221, and more particularly as set forth in the Egan patent, U.S. Pat. No. 3,433,645, incorporated herein by reference. The fatty acid radicals of ethoxylated monoglycerides broadly are higher fatty acid chains having about 12 to 18 carbon atoms. One suitable ethoxylated mono- diglyceride that may be employed in the present invention is Durfax-EOM (trademark) marketed by Durkee Foods Division of SCM Corporation. This emulsifier is manufactured from hydrogenated vegetable oils and has an HLB value of about 13, is fluid at ambient temperature, has an acid value maximum of 2.0, a hydroxyl value of 60-80, a saponification value of 65-75 and an oxyethylene content of 60.5-65.0%. Other ethoxylated fatty acid esters which may be employed in the present invention are the polysorbates, such as polyoxyethylene (20) sorbitan monostearate (polysorbate 60) or polyoxyethylene (20) sorbitan monooleate (polysorbate 80). These emulsifiers are sold under the trademarks "Durfax 60" and "Durfax 80", respectively, by Durkee Foods Division of SCM Corporation. They have an HLB value of about 13-16 and are fluid at ambient temperature. Ethoxylated mono- diglycerides may be prepared by reacting ethylene oxide with a mono- diglyceride mixture at temperatures of about 125° C., such as suggested in the Egan patent, U.S. Pat. No. 3,490,918, and incorporated herein by reference. Similar known procedures are available for the preparation of the polysorbates. Preferred compounds for use in the formulations of the present invention are the high HLB polyglycerol esters having HLB values ranging from 10 to 16. These esters are generally a mixture of monounsaturated and saturated fatty acid esters of a mixture of polyglycerols in which the range of polyglycerol is from octaglycerol to decaglycerol, with one or two fatty acyl ester groups per molecule. The monounsaturated and saturated fatty acids contain 16 to 18 carbon atoms and are typically derived from corn oil, cottonseed oil, lard, palm oil, peanut oil, safflower oil, sesame oil, soybean oil, tallow, and tall oil and the fatty acids derived from these substances may be either hydrogenated or unhydrogenated. The polyglycerol mixture is prepared by the polymerization of glycerol with an alkaline catalyst as exemplified in U.S. Pat. No. 3,637,774, or an acid catalyst as exemplified in U.S. Pat. No. 3,968,169. Polyglycerol esters are obtained by then esterifying the polyglycerol by reaction with fatty acids in direct esterification or by reaction with fats and oils in an interesterification process. Suitable polyglycerol esters broadly have a hydroxyl value of about 400 to 600, a saponification number of about 60 to 100, and acid values of less than about 10. The range of possible polyglycerol esters is small and can range from a monoesterified octaglycerol to a diesterified decaglycerol, with the iodine value of the fatty acid ranging from 0 to 90. A particularly suitable polyglycerol ester of fatty acids useful in the process of the present invention is octaglycerol monostearate (8-1-S). This compound has a calculated HLB value of about 13 and is of solid or plastic consistency at ambient temperature, having a Mettler Dropping Point of about 52°-57° C. Octaglycerol monostearate typically contains about 60-68% stearic acid and has a hydroxyl number of 500-570, a saponification number of 77-88, an acid number of under 5, and an IV of about 65-85. Another suitable polyglycerol ester of fatty acids useful in the process of the present invention is octaglycerol monooleate (8-1-0). This compound has a calculated HLB value of about 13-16 and is of fluid consistency at ambient temperature. Octaglycerol monooleate typically contains about 60-68% oleic acid and has a hydroxyl number of 500-570, a saponification number of 68-85 and an acid number of under 4.1. Still another suitable polyglycerol ester is decaglycerol distearate. The sugar esters and processes for making them are disclosed in a number of prior patents including the Sugar Research Foundation, Inc. patents to Hass, U.S. Pat. Nos. 2,893,990 and 2,970,142; the State of Nebraska patents to Osipow et al., U.S. Pat. Nos. 3,480,616 and 3,644,333; and Dai-Ichikogyo Seiyaku Co., Ltd. U.S. Pat. No. 3,792,041. One particularly suitable sugar ester is OW-1570 (trademark) manufactured by Ryoto Company of Japan. This emulsifier can be characterized as sucrose monooleate with 70% monoester. It has a fatty acid composition of approximately 60% oleic acid, and is fluid with a 60% water content. Its HLB value is about 15. Because of the presence of the alcohol, an emulsifying amount or usage level of emulsifier required is relatively high, on the order of about 0.14% to about 0.7% by weight, based on the entire weight of the alcohol/fat/water emulsion (or about 1.4 grams per liter to about 7 grams per liter, on a weight/volume basis). At upper usage levels, the ethoxylated mono- diglycerides and polysorbates (which both have detectable flavors) are likely to adversely affect the beverage flavor, making the polyglycerol esters preferred emulsifiers. Also, the polysorbates and ethoxylated mono- and diglycerides are unsaturated compounds, tending to make them subject to spoilage. The polyglycerol ester compound 8-1-S is substantially fully saturated, making this compound very stable in the presence of oxygen. The sugar esters are presently not food approved in the United States. In cream-containing beverages (40% butterfat in the dairy phase), the octaglycerol monostearate, being solid in consistency, offers the best results and, again, is preferred. Broadly, the beverage formulations of the present invention will be made with milk or cream and then will be kept refrigerated until consumption, to prevent spoiling, although the presence of the alcohol and sugar may make this unnecessary, particularly where the amount of alcohol employed is relatively high. Milk and cream are traditional ingredients in milk or cream-containing alcoholic beverages, and the purpose of the present invention, in part, is to duplicate such beverages. In beverages containing relatively low amounts of alcohol and/or sugar, particularly at lower levels of sugar and alcohol, refrigeration may be necessary. The present invention is particularly useful with heavy cream-containing beverages which are 34 proof (having about 17% alcohol). With the emulsifiers of the present invention, particularly octaglycerol monostearate (8-1-S), the beverages are extremely stable against phase separation and also are stable against spoilage. Typically, the heavy cream will be present at a level of about 30-40%. Heavy cream is about 40% butterfat, giving the composition of this embodiment of the present invention a fat content of about 12-16%. In the beverages of the present invention, the sugar content can vary substantially, depending upon taste. Typically, it will be about 20-30% basis of the entire weight of the emulsion. The beverages of the present invention can contain many other ingredients than those mentioned above, for instance flavoring (both natural and synthetic), colorants, gum stabilizers, other polysaccharides such as starch, other carbohydrates such as corn syrup solids, and egg or egg-derived products. In all cases, the balance of the formulation, after establishing levels of the above functional ingredients, is water. As the carbohydrate, there can be used corn syrups with D. E. values of 24 to 70 or higher, molasses, maltose, ribose, galactose, xylose, arabinose, honey, lactose, sucrose, dextrin, water soluble starch, pregelatinized starch, gum arabic, larch gum arabinogalactan, d-glucose, modified starches of the type set forth in Schoch U.S. Pat. No. 2,876,160, e.g., hypochlorite-oxidized cornstarch, torrefaction or roasted dextrins, etherified starches including hydroxyethyl, hydroxypropyl, methyl and ethyl derivatives, starch esters, e.g., starch acetate and starch sulfonate, waxy maize starch, waxy sorghum starch, and converted starches having a D. E. value of 4 to 20. Colloidal carbohydrate stabilizers include cellulose ethers such as methyl cellulose, e.g., the product marketed under the trademark "Methocel MC" (dimethyl ether of cellulose having 1.64-1.92 methoxy groups per glucose unit), mixed methyl hydropropyl cellulose, e.g., the product marketed under the trademark "methocel 90 HG" (an etherified cellulose having 1.08-1.42 methoxy groups and 0.1-0.3 hydroxypropyl groups per glucose unit) and the product marketed under the trademark "Methocel 65 HG" (an etherified cellulose having 1.61-1.75 methoxy groups and 0.1-0.18 hydroxypropyl groups per glucose unit), carboxymethyl cellulose, low methoxy pectin, i.e., pectin having a methoxy content of 2.5-4.5%, inulin, guar, Irish moss (carragheen), sodium alginate, gum tragacanth, gum karaya and locust bean gum. The beverages of the present invention are pasteurized in conventional fashion, e.g., at 140°-165° F. for 35 minutes to one hour, usually 155°-160° F., for 35 minutes. The beverages are then homogenized in conventional fashion to a particle size between 1 to 10 microns. For many uses the particle size of the emulsified material is not over 5 microns; and preferably in preparing the alcohol products of the present invention, particularly heavy cream-containing products, the particle size is reduced to less than about 3 microns, preferably about 1 to 1.5 microns. Homogenization is carried out in one or two stages at about the pasteurization temperature and at pressures which can vary from 500 psi to 5,000 psi, or somewhat higher. After homogenization, the beverages are cooled and packaged. They remained stable, showing neither spoilage nor phase separation for a prolonged period, even when stored at room temperature. In the following example and claims, all percentages are on a weight basis, based on the total weight of the beverage unless otherwise specified. EXAMPLE The following formula and process yielded a stable emulsion: ______________________________________Ingredients Weight Percent (Approx.)______________________________________Heavy cream (40% fat) 36Alcohol to yield 34 proofSugar 24-26%Water BalanceSantone 8-1-S flakes 2-10 grams/1,000 mls______________________________________ The ingredients were added to a mixing boat and mixed and pasteurized at about 155° F., after which they were homogenized in a two-stage homogenizer at pressures of about 3,500 psi and 500 psi to produce a particle size of about 1-1.5 microns. In this example, the Santone 8-1-S is in flake form, making it easy to use. It is normally very sticky and difficult to use, but by combining it with a carrier such as stearine (in this example, an inert ingredient) in the ratio of about 70% 8-1-S to about 30% stearine, a dry, non-sticky, flake form is obtained. The actual amount of 8-1-S present in the above formula is thus about 1.4 to 7 grams per liter, or on a percentage weight basis, about 0.14 to 0.7 percent. Optimum results were obtained with about 0.6% flakes, or about 0.42% 8-1-S.

An homogenized cream/alcohol-containing beverage comprising cream or milk and alcohol in drink preparation amounts, and a high HLB emulsifier selected from the group consisting of high HLB polyglycerol esters of fatty acids, ethoxylated fatty acid esters; and sugar esters, each in an emulsifying amount.

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a non-provisional application which claims benefit under 35 USC §119(e) to U.S. Provisional Application Ser. No. 61/421,509 filed Dec. 9, 2010, entitled “CONDENSATION OF GLYCOLS TO PRODUCE BIOFUELS,” which is incorporated herein in its entirety. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT None. FIELD OF THE INVENTION The present disclosure relates to the field of biomass-derived transportation fuels. More specifically, it relates to methods for converting light glycol feeds originating from biomass into polyglycol products suitable for use as a bio-derived fuel or cetane-enhancing fuel additive. BACKGROUND There is a great interest in the discovery of alternative sources of fuels and chemicals from resources other than petroleum. Development of non-petroleum-based liquid transportation fuels may provide economic and environmental benefits, while also increasing national security by decreasing reliance on non-domestic energy sources. Biomass, such as plants and animal fats, represent a major alternative source of hydrocarbons that can be converted into fuels. Liquid fuels derived from biomass are rapidly entering the market, driven by both need for increased national energy independence and rapid fluctuations in the cost of petroleum products. In 2007, the Energy Independence and Security Act was passed in the United States, which requires increasing quantities of bio-derived fuels to be produced over time. Similarly, the European Union directive 2003/30/EC promotes the use of biofuels or other renewable fuels. The directive has set a minimum percentage of biofuels to replace diesel or gasoline for transport purposes so, that by the end of 2010 there should be a 5.75% minimum proportion of biofuels in all gasoline and diesel fuels sold. To meet these mandates, it is essential to develop more efficient processes to convert bio-derived compounds into fuels that can fulfill these government mandates, as well as future global energy needs. The carbohydrates found in plants and animals can be used to produce fuel range hydrocarbons. However, many carbohydrates (e.g., starch) are undesirable as feed stocks for creating biomass-derived fuels due to the costs associated with converting them to a useable form. The chemical structure of some carbohydrates makes them difficult to convert, and conversion processes may produce low yields of desirable products. Carbohydrates that are difficult to convert include compounds with low effective hydrogen to carbon ratios, including carbohydrates such as starches and sugars, and other oxygenates with low effective hydrogen including carboxylic acids and anhydrides, light glycols, glycerin and other polyols and short chain aldehydes. As such, development of an efficient and inexpensive process for converting one or more of these difficult-to-convert biomass feedstocks into a form suitable for use as a fuel additive could be a significant contribution to the art and to the economy. Glycerol is a significant side-product of the trans-esterification reaction utilized to convert plant oils and animal fats into biofuels, and some work has been done examining ways to utilize glycerol. Karinen, et al. have reported methods for the etherification of glycerol and isobutene, while papers by Frustieri, et al. and Keplacova, et al., both include methods for catalytic etherification of glycerol by tert-butyl alcohol. U.S. Patent App. Pub. US2010/0094062 describes a process for the etherification of glycerol with an alkene or alkyne, followed by nitration of a remaining hydroxyl group. A portion of the process claimed in US2008/0300435 pertains to the dimerization/condensation of alcohols such as pentanol or isopropyl alcohol. However, to date, no methods have demonstrated an efficient process for the etherification of biologically-derived light glycol feedstock, such as ethylene glycol or propylene glycol, that results in a product suitable for subsequent use as a fuel additive. BRIEF SUMMARY Towards this goal, we disclose herein a novel process for efficiently converting biomass-derived light glycols, such as ethylene glycol and propylene glycol, into low molecular weight poly-glycol products useful as oxygenated cetane enhancers in transportation fuels. Whereas glycerol is a common byproduct of transesterification processes, light glycol streams are often obtained by the moderate hydrogenolysis of larger biomass-derived oxygenates such as alditols, cleaving backbone carbon-carbon linkages to form this feed. Glycols are easier to utilize as feedstock than their parent alditols in that glycols are liquids at room temperature and may be distilled to remove impurities rather than having to rely on other purification techniques (e.g. ion-exchange for metals removal). In contrast, alditols in the five to six carbon range are solids at room temperature and tend to decompose when heated above their melting points. Unlike some unsaturated biomass derived oxygenates, glycols are stable and may be stored long term without special measures to prevent degradation. Unfortunately, glycols are not suitable for direct blending into fuels due to miscibility issues. However, converting these glycols to low molecular weight poly-glycols (LMWPG) helps resolve this problem. During the conventional processing of hydrocarbons to produce fuels, removing oxygen involves reacting oxygen containing compounds with hydrogen to produce water. However, the underlying chemistry behind the conversion of the present disclosure involves acid-catalyzed condensation reactions that do not require hydrogen for oxygen removal. This reduces greenhouse gas emissions while also reducing the operational cost associated with production of hydrogen. Some oxygen from the feed is left in the final product resulting in the product maintaining much of the volume of the original starting material. Finally, these condensation reactions may be conducted at much lower temperatures than conventional oxygen removal processes, resulting in further savings. The present disclosure pertains to using solid acidic catalysts to convert biomass-derived glycols into di-, tri-, and some larger low molecular weight polyglycols (LMWPG), followed by steps to increase miscibility of the LMWPG with liquid hydrocarbon fuels. Derivatives of these LMWPG fall into a category of materials termed oxygenated cetane improvers, which are larger, predominantly linear compounds with oxygen substituted for carbon periodically along the backbone. The oxygen content of oxygenated cetane improvers varies depending on the feedstream used in their formation. However, a National Renewable Energy Laboratory report by Murphy, et al. shows that number of polyglycols have been calculated to possess a high cetane number. In addition, preliminary findings by Tijm, et. al. have shown that several LMWPG, when added to premium diesel fuel at 10-11% (by wt.), reduce particulate emissions during combustion by up to 28% versus unmodified premium diesel. Certain embodiments of the invention disclosed herein provide a process for converting glycols (such as, for example, ethylene glycol and propylene glycol) into products suitable for use as fuel additives that comprises the steps of: (a) providing a biomass-derived feedstream comprising light glycols, where the glycols contain two, three or four carbon atoms, (b) contacting the feedstream with a first catalyst in a reactor, where the contacting results in an acidic condensation reaction that converts a least a portion of the feedstream to condensation products, and where said condensation products possess at least 4 carbon atoms and one ether functional group, (c) converting at least a portion of the remaining hydroxyl functional groups on the condensation products from step (b) to ether functional groups by combining the condensation products with a second catalyst to produce a liquid hydrocarbon mixture suitable for use as an additive to liquid hydrocarbon fuels, wherein the converting takes place in the presence of an olefin, monofunctional alcohol or mixtures thereof, and wherein the liquid hydrocarbon mixture has increased miscibility in liquid hydrocarbon fuels as a result of step c). Certain alternative embodiments of the invention disclosed herein provide a process for converting glycols (such as, for example, ethylene glycol and propylene glycol) into products suitable for use as fuel additives that comprises the steps of: (a) providing a biomass-derived feedstream comprising light glycols, where the glycols contain two, three or four carbon atoms, (b) contacting the feedstream with a first catalyst in a reactor, where the contacting results in an acidic condensation reaction that converts a least a portion of the feedstream to condensation products, and where said condensation products possess at least 4 carbon atoms and one ether functional group, (c) reducing at least a portion of the remaining hydroxyl groups on the condensation products by combining the condensation products with a second catalyst in the presence of hydrogen to produce water and a liquid hydrocarbon mixture that is suitable for use as an additive for a liquid hydrocarbon fuel. This liquid hydrocarbon mixture has increased miscibility in liquid hydrocarbon fuels as a result of this reduction step. In certain embodiments, the functions of the first and second catalyst are performed by the same catalyst. In certain embodiments, the process additionally comprises combining the liquid hydrocarbon mixture of step (c) with a liquid hydrocarbon fuel to produce an improved liquid hydrocarbon fuel, wherein the improved liquid hydrocarbon fuel has improved combustion properties that may include increased cetane number, decreased emissions of environmental pollutants during combustion, or both. The first catalyst may comprise at least two elements, one selected from Group 4 of the periodic table, and the other selected from Group 6 of the periodic table. Alternatively, the first catalyst may be a microporous molecular sieve selected from the group consisting of crystalline silicoaluminophosphates and aluminosilicates, that has been chemically treated to decrease catalytic activity outside the internal channels of the catalyst. Preferably, the pore diameter of the molecular sieve catalyst restricts the formation of circular products inside its pores. In certain embodiments, the second catalyst may be an acidic macroreticular ion-exchange resin. In other embodiments, the second catalyst may be a microporous molecular sieve selected from the group consisting of crystalline silicoaluminophosphates and aluminosilicates, that has been chemically treated to decrease catalytic activity outside the internal channels of the catalyst. BRIEF DESCRIPTION OF THE DRAWINGS FIG.1 illustrates an acidic condensation of the current disclosure also referred to as etherification. FIG.2 illustrates outlines how a non-preferred cyclic product (p-dioxane) can be formed from the condensation product of two ethylene glycol molecules. DETAILED DESCRIPTION Process conditions for conducting condensation reactions are relatively mild when compared to other industrial processes, such as conventional naphtha hydrodesulfurization, which normally requires temperatures in the range of 285° C. to 370° C. Low temperatures are advantageous since at higher temperature elimination becomes a competing reaction mechanism. Elimination, like condensation, involves the removal of a small molecule from a parent, but there is no coupling associated with the reaction. Elimination results in the production of an unsaturated product (e.g., ethanol to ethylene.) While these limits exist, yields for this process are typically sufficient to operate at the commercial level for chemical production. The acidic condensation of the current disclosure could also be referred to as etherification, and is illustrated in FIG. 1 . Depicted in the first line, the acid catalyst donates a proton to a hydroxyl group of a first glycol molecule. By definition, a glycol is a diol where the two hydroxyl groups are attached to different carbons. Thus, the R groups shown in FIG. 1 represent a hydrocarbon chain comprising a second hydroxyl moiety. Referring to the second line of FIG. 1 , a hydroxyl group from a second glycol molecule to reacts with the electrophilic carbon adjacent to the proton-accepting hydroxyl. Finally, the third line of FIG. 1 depicts removal of a water molecule (and proton) forming an ether bond between the two glycols. Acid-catalyzed condensation of primary alcohols in the homogeneously catalyzed case occurs via an S N 2 mechanism. In this type of mechanism, the transition state involves the attacking nucleophile driving off the leaving group in a concerted mechanism. This acid catalyzed condensation reaction is distinct from the base-catalyzed condensation reaction developed by Guerbet, which instead produces branched, saturated alcohols and not ethers. Examples of the Guerbet condensation reaction being utilized to form saturated branched hydrocarbons are shown in U.S. Pat. No. 7,049,476 and US2008/0302001. Typical biomass-derived molecules suitable for conversion to LMWPG by the processes described herein include any diol comprising two to four carbon atoms. Examples include ethylene glycol, propylene glycol, 1,3-propanediol, 1,2,-butanediol, 1,3,-butanediol, 2,3-butanediol, and 1,4-butanediol. As mentioned above, it is possible to convert glycols into di-, tri-, and some larger LMWPG using a solid acidic catalyst. Derivatives of these LMWPG fall into a category of materials termed oxygenated cetane improvers. Oxygenated cetane improvers are larger, predominantly linear compounds with oxygen substituted for carbon periodically along the backbone. The oxygen content of oxygenated cetane improvers varies depending on the feedstream used in their formation. However, a National Renewable Energy Laboratory report by Murphy, et al. shows that number of polyglycols have been calculated to possess a high cetane number. In addition, preliminary findings by Tijm, et. al. have shown that several LMWPG, when added to premium diesel fuel at 10-11% (by wt.), reduce particulate emissions during combustion by up to 28% versus unmodified premium diesel. The condensation reactions associated with the processes described herein are generally conducted at a temperature ranging from about 100° C. to about 300° C. More preferably, these reactions are conducted at a temperature ranging from about 120° to about 260° C. The condensation reactions are generally conducted at a pressure ranging from about 200 kPa to about 8000 kPa. Preferably, reactions are conducted at a pressure ranging from about 500 kPa to about 5000 kPa. Additionally, condensation reactions of the present disclosure are generally conducted with a feedstream flow rate ranging from about 0.1 h −1 liquid weight hourly space velocity (LWHSV) to about 20 h −1 LWHSV. Preferably, reactions are conducted with a feedstream flow rate ranging from about 0.5 h −1 LWHSV to about 15 h −1 LWHSV. The condensation catalyst utilized may be any catalyst capable of condensing light glycols to produce LMWPG. Preferably, the catalyst is an acidic catalyst suitable for such reactions, such as tungstated zirconias (for example, WO 3 /ZrO 2 ), metal loaded tungstated zirconias (for example, Pt—WO 3 /ZrO 2 ), heteropoly acids (for example, H 4 SiW 12 O 40 ), supported sulfonic acids (for example, acidic Amberlyst™ ion-exchange resins [Rohm and Haas]). Other catalysts useful for such condensation reactions may include acidic metal oxide catalysts, such as niobium pentoxide. Preferably, the catalyst is a microporous molecular sieve selected from crystalline silicoaluminophosphates and aluminosilicates with a three-dimensional pore structure that selectively favors the production of linear condensation products within the pores of the zeolite, while minimizing production of undesirable cyclic secondary products. Such undesirable products include p-dioxane. FIG. 2 outlines how this non-preferred cyclic product 121 can be formed from the condensation product 115 of two ethylene glycol molecules 101 . In certain embodiments, the condensation catalyst is a surface-passivated zeolite (such as, for example, H-Y, H-USY, H-mordenite, or H-ZSM-5) that selectively favors the production of linear LMWPG within the internal pores of the zeolite, while further minimizing production of undesirable cyclic secondary products on the zeolite surface. P-dioxane is a bulky, cyclic structure that is less likely to form within the confines of a zeolite channel system at low temperatures. Selectivity toward the formation of LMWPG may be enhanced by surface passivation of the zeolite to block activity outside of the channel system. Methods for surface passivation of zeolites are familiar to those with knowledge in the art, and one example of a zeolite passivation procedure is provided in Example II of the current disclosure. Creating selectivity towards the favored primary poly-glycol product is important for the economic viability of the process at industrial scale, since p-dioxane is unsuitable for blending into fuels, and is a stable product that is difficult to convert back to a form that is useful as a biofuel component. Following condensation of the light glycol feed to form a LMWPG, in certain embodiments the remaining hydroxyl groups are modified by an additional “capping” step to produce a poly-glycol derivative. This end-capping of the terminal hydroxyl groups may be accomplished by any catalyst capable of catalyzing an etherification reaction between the remaining terminal hydroxyl groups and an olefin. The end product would preferably have increased miscibility in liquid hydrocarbon fuels, and thus, be more suitable for use as a fuel additive. Such capping techniques are understood by individuals having knowledge in the art, and examples of such techniques are provided in the previously mentioned papers by Karinen, et. al., Frustieri, et. al. and Keplacova, et. al. In certain alternative embodiments, the remaining hydroxyl groups that are present on the LMWPG following condensation of the light glycol feed are instead “capped” by an additional acidic condensation reaction in the presence of a monofunctional alcohol (such as, for example, methanol, ethanol or propanol). This step may be performed with the catalyst of step b), for example, or any other catalyst capable of catalyzing an etherification reaction between the remaining terminal hydroxyl groups of the LMWPG and the monofunctional alcohol. The monofunctional alcohol has only one functional group capable of participating in a further round of etherification, thus effectively preventing further growth of the polymer. The end product would preferably have increased miscibility in liquid hydrocarbon fuels, and thus, be more suitable for use as a fuel additive. In still other embodiments, the remaining hydroxyl groups that are present on the LMWPG following condensation of the light glycol feed are instead “capped” by mild hydrodeoxygenation (HDO) of the remaining hydroxyl functional groups. It is important that the HDO step be mild so as to not completely remove all oxygen from the LMWPG, as a certain amount of oxygen in the final product is desirable. This HDO step may be catalyzed by any of a number of commercially available catalysts, including commercial hydrotreating catalysts comprising Co and Mo, or Ni and Mo. Procedures for conducting such HDO reactions are commonly known in the art. The end product would preferably have increased miscibility in liquid hydrocarbon fuels, and thus, be more suitable for use as a fuel additive. EXAMPLES The following examples are each intended to be illustrative of a specific embodiment of the present invention in order to teach one of ordinary skill in the art how to make and use the invention. They are not intended to limit the scope of the invention in any way. Example I Preparation of Catalysts: 40 wt % H 4 SiW 12 O 40 /SiO 2 was prepared by incipient wetness impregnation. H 4 SiW 12 O 40 (Sigma-Aldrich) was dissolved in ethanol and added dropwise to Davicat SI 1103 (320 m 2 /g, −40/+60 mesh.) Samples were sealed for 24 hours and then dried for 12 hours at 90° C. in flowing nitrogen. 1 wt % Pt—WO 3 /ZrO 2 was prepared by precipitation of Zr(OH) 4 followed by the loadings of tungsten and platinum via incipient wetness impregnation. Pt was loaded onto the catalyst using aqueous hexachloroplatinic acid. Catalysts were dried at 150° C. for 6 hours, and calcined at 300° C. overnight in flowing air. H-MOR (Si/Al=10), NH4-USY (Si/Al=2.6), and TPA-ZSM-5 (Si/Al=15) were obtained from Zeolyst International. Extrudates were crushed and sieved to −20/+40 mesh. Zeolites containing template or in the ammonium form were converted into the acidic form by calcining in a muffle furnace under flowing air prior to use. Excess air was flowed over the catalyst while the samples were heated using a gradual heat/soak temperature profile to a final temperature of 450° C. The final temperature was maintained overnight (>12 hours.) Example II Hypothetical Example: Passivation of a Zeolite Catalyst with Either Poly(phenylmethyl)siloxane or Tetraethylorthosilicate: Zeolite catalysts useful in certain embodiments of the invention may be chemically-modified to passivate (i.e., block active sites on) the external surface of the catalyst, thereby increasing selectivity for the production of LMWPG. One examples of how this can be achieved is outlined in U.S. Pat. No. 6,228,789, which pertains to a method for silylation of zeolite catalysts, and is incorporated herein by reference. A zeolite H-ZSM-5 was contacted to incipient wetness with a 50 wt % solution of poly(phenylmethyl)siloxane (PPMS) in cyclohexane, and the catalyst was not pre-calcined prior to contacting. After loading of the catalyst, it was dried and calcined at 538° C. for 6 hrs. Alternatively, the H-ZSM-5 catalyst was loaded with a 50 wt. % solution of tetraethylorthosilicate (TEOS) under conditions identical to those used for loading with PPMS. Example III Catalytic Conversion Test Conditions: Unless otherwise noted, catalysts were tested in a standard, ¾-inch diameter down-flow reactor. A bed of heated glass beads was utilized upstream from the catalyst to preheat the feed to reaction temperature prior to contacting the catalyst. Typically 6 mL of catalyst was diluted in an inert material (alundum) to a constant 13 mL bed volume for screening runs. The reactor was heated using a three-zone Thermcraft™ furnace with independent temperature control for each zone. Liquid feed was delivered to the system by an ISCO™ 1000D syringe pump, and system pressure was controlled by a Tescom™ backpressure regulator. Samples were taken at one hour intervals, and conversion and selectivity percentages (unless otherwise noted) were calculated by averaging data obtained from three different samples taken at different time points. Catalysts were dried in-situ at the desired operating temperature for a minimum period of 30 minutes in at least 100 sccm H 2 at 2758 kPa psig prior to each run. Pt containing catalysts were reduced for a minimum of 30 minutes at 300° C. and 2758 kPa in 100 sccm of H 2 . Except as noted, runs were performed as follows: Ethylene glycol was obtained from Sigma-Aldrich™ (97% purity) and diluted to 50 vol. % in water, and was fed to the reactor at a constant liquid feed rate of 30 mL/hr. Reactions were typically performed at 200° C., 5.0 h −1 LVHSV, and 2758 kPa. Hydrogen was flowed at 100 sccm during screening runs as some catalysts tested needed spillover hydrogen for activity. Liquid sample collection began 1 hour after starting the feed. Samples were acquired at 1 hour intervals for 5 hours and analyzed on an Agilent™ 7890A gas chromatograph equipped with an Agilent™ HP-5 capillary column, and a flame ionization detector (FID). Ambient temperature non-condensable products were analyzed on-stream using a HP-5 capillary column with FID detection. Example IV The tungstated zirconia catalyst Pt—WO 3 /ZrO 2 was prepared as detailed in Example 1, and found to convert 18.5% (w/v) of the feed during the experiment. However, selectivity for the formation of LMWPG was only 1.7% (w/v). Instead, this catalyst produced a relatively large quantity of ethanol from the ethylene glycol feedstock. While not wishing to be limited by theory, it is hypothesized that this ethanol was formed by the intramolecular dehydration of ethylene glycol to form acetaldehyde, followed by reduction of the acetaldehyde at the Pt sites of the catalyst to form ethanol. Alternatively, ethanol may have formed through direct hydrogenolysis at Pt sites. Example V A member of the heteropoly acid catalyst family (with the formula H 4 SiW 12 O 40 /SiO 2 ) was tested for its ability to convert the glycol feedstock to LMWPG. At a run temp of 250° C., utilizing undiluted ethylene glycol at a feed rate of 15 ml/hr, this catalyst converted 74.7% of the feedstock (average of samples taken at third and fourth hours), with a selectivity of 20.3% for the formation of LMWPG. However, this catalyst produced a large percentage of p-dioxane product, which is unsuitable for use as a biofuel, or a cetane-increasing fuel additive. p-dioxane is formed from the product of an intermolecular condensation between two ethylene glycols molecules. The primary product of this condensation, diethylene glycol, can undergo intramolecular condensation and circularize to form p-dioxane. This is not desirable, because p-dioxane is not suitable for use as a cetane-enhancing additive, and is a relatively stable product that is difficult to convert into back into a form that can be used as a fuel, or fuel additive. Example VI The zeolite catalysts USY, mordenite, and ZSM-5 were obtained and used with similar Si/Al ratios for comparison (the Si/Al ratios were 2.6, 10 and 15, respectively.) The relatively low Si/Al ratios were selected to maximize the acid site quantity for each catalyst. Each zeolite catalyst exhibited conversion of the ethylene glycol feed (See Table 1) to form LMWPG. TABLE 1 Conversion of ethylene glycol to LMWPG by several zeolite catalysts. Si/Al % Selectivity Catalyst Ratio % Conv. for LMWPG H-USY 2.6 0.6 58.2 H-MOR (mordenite) 10 4.7 6.2 H-ZSM-5 15 15.8 61.5 Reaction products in addition to LMWPG were observed, including acetaldehyde and p-dioxane. The acetaldehyde was hypothesized to have formed by the intramolecular dehydration of ethylene glycol, while p-dioxane was thought to have formed by the mechanism outlined previously. Interestingly, the USY and ZSM-5 zeolites exhibited higher selectivity for the production of LMWPG than with the other catalysts tested previously. Example VII The ZSM-5 zeolite catalyst was selected for further testing to optimize reaction conditions for converting the ethylene glycol feed stock to LMWPG. Conditions of pressure, temperature and flow rate were altered, and the effect on percent conversion and selectivity for the formation of LMWPG is shown in Table 2: TABLE 2 Conversion of ethylene glycol to LMWPG at various reaction conditions: % % Temp. Pressure LWHSV Run Conversion Selectivity (° C.) (KPa) (hr −1 ) 1 1.20 71.7 126.5 689 1.5 2 0.14 53.6 126.5 689 15.0 3 0.45 93.2 124.5 2758 1.5 4 0.55 92.8 128 2758 1.5 5 0.21 100 126.5 2758 15.0 6 0.96 87.4 134.5 689 15.0 7 0.11 71.5 149 1724 8.25 8 1.60 85.4 154.5 1724 8.25 9 40.60 62.4 174 689 1.5 10 3.60 42.4 175.5 689 15.0 11 48.90 59.7 177.5 2758 1.5 12 1.80 84.5 174.5 2758 15.0 13 53.30 56.2 183.5 689 1.5 14 5.50 81.0 182 2758 15.0 DEFINITIONS As used herein, the term “liquid weight hourly space velocity” or “LWHSV” refers to the liquid weight hourly space velocity. As used herein, the term “cetane” or “cetane number” refers to the cetane number of a fuel as measured by the ASTM (American Society for Testing and Materials) D613 or D6890 standard. As used herein, the term “transportation fuel” refers to any liquid hydrocarbon mixture used as a fuel for powering engines, including gasoline, diesel and jet fuels. Further modifications and alternative embodiments of various aspects of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the invention. It is to be understood that the forms of the invention shown and described herein are to be taken as examples of embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed and certain features of the invention may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the invention. Changes may be made in the elements described herein without departing from the spirit and scope of the invention as described in the following claims. REFERENCES All of the references cited herein are expressly incorporated by reference. Incorporated references are listed again here for convenience: 1. US2010/0094062 (Rabello; Ferreiral; Menenzes); “Cetane Number Increasing Process and Additive for Diesel Fuel.” 2. US2008/0300435 (Cortright; Blommel); “Synthesis of Liquid Fuels and Chemicals From Oxygenated Hydrocarbons.” 3. US2008/0302001 (Koivusalmi; Piiola; Aalto) “Process for Producing Branched Hydrocarbons.” 4. U.S. Pat. No. 7,049,476 (O'Lenick, Jr.) “Guerbet Polymers” (2006). 5. U.S. Pat. No. 6,228,789 (Wu; Drake) “Silylated Water Vapor Treated Zinc or Gallium Promoted Zeolite and Use Thereof for the Conversion of Non-aromatic Hydrocarbons to Olefins and Aromatic Hydrocarbons” (2001). 6. Klepacova, K., et al., “Etherification of Glycerol and Ethylene Glycol by Isobutylene.” Applied Catalysis A: General 328: 1-13 (2007). 7. Klepacova, K., et al., “tert-Butylation of Glycerol Catalyzed by Ion-Exchange Resins.” Applied Catalysis A: General 294: 141-147 (2005). 8. Karinen, R. et al., “New Biocomponents from Glycerol” Applied Catalysis A: General 306: 128-133 (2006). 9. Frusteri, F., et al., “Catalytic Etherification Of Glycerol By tert-Butyl Alcohol To Produce Oxygenated Additives For Diesel Fuel.” Applied Catalysis A: General 367: 77-83 (2009). 10. Tijm, P. et al., “Effect of Oxygenated Cetane Improver on Diesel Engine Combustion & Emissions” http://www.energy.psu.edu/tecetane.html 11. Murphy, M. et al., “Compendium of Experimental Cetane Number Data” NREL/SR-540-36805 (2004). http://www.nrel.gov/vehiclesandfuels/pdfs/sr368051.pdf

The present disclosure relates to methods for converting light glycol streams of biological origin into products suitable for use as oxygenated fuel additives. These methods involve the acidic condensation of light glycols to form larger products, termed low molecular weight poly-glycols. The remaining hydroxyl functional groups of the poly-glycol products are then modified to decrease the overall polarity of the products, and improve their suitability for use as an oxygenated fuel additive.

TECHNICAL FIELD The present invention relates to shift mechanisms for manual transmissions in motor vehicles. More particularly, this invention relates to shift mechanisms with a shift shaft largely internal to a transmission housing for making gear range selections. Axial displacement of the shift shaft is used to select the desired gear range. Rotary displacement of the shift shaft is used to engage the desired gear. A select lever external to the transmission housing is used to axially displace the shift shaft. A shift lever, also external to the transmission housing, is used to rotatively displace the shift shaft. BACKGROUND OF THE INVENTION Conventional shift mechanisms for manual transmissions permit shifting from second gear to first gear when it is desired to shift from second gear to third gear. Synchronizers within the transmission can provide some resistance to downshifting, but that resistance can be overcome by the vehicle operator. SUMMARY OF THE INVENTION The present invention blocks a shift from second gear to first gear when the last preceding shift is a first gear to second gear shift. The transmission can be shifted into any gear except first. No other shift sequence is restricted. It is an object of this invention to inhibit shifting to first gear after a first gear to second gear shift. It is also an object of this invention to provide a device which restricts shifting to first gear after a first gear to second gear shift. It is further an object of this invention to provide a mechanism for a transmission having a shift lever, a select lever rotatively mounted to a transmission housing, and a shift shaft which blocks shifting from second gear into first gear after a first gear to second gear shift. These and other objects and advantages will be more apparent from the following description and drawings. DESCRIPTION OF THE DRAWINGS FIGS. 1-4 show the parts of the shift control attaching to the shift shaft from the distal end of the shift shaft. Each figure shows the parts in different relative positions which correspond to particular gear positions. FIG. 1 shows the shift lever in the neutral position and the select lever in the 1-2 gear range position with the shift lever disengaged from the shift lever cam. FIG. 2 shows the shift lever in the first gear position and the select lever in the 1-2 gear range position after a neutral to first gear shift. FIG. 3 shows the shift lever in the neutral position and the select lever in the 1-2 gear range position and the shift lever in Neutral after being shifted from first gear to neutral. FIG. 4 shows the shift lever in second gear after being shifted from first to neutral to second gear while maintaining the select lever in the 1-2 gear range position. FIG. 5 shows a side view of the shift control in the direction of arrows 5 of FIG. 3. FIG. 6 shows a sectional view of the shift control in the direction of arrows 6 of FIG. 3. DESCRIPTION OF THE PREFERRED EMBODIMENT FIGS. 1-6 all show an inhibitor 10 for a manual transmission shift control 12, located on the exterior of a transmission housing 14. The transmission has a plurality of drive gears, including but not limited to a first gear and a second gear as well as neutral where no drive gears are engaged. FIGS. 1-4 show the relative positions of the elements of the inhibitor 10 as the transmission is shifted from neutral to first gear and then from first gear to second gear. FIG. 5 highlights the rotatable operation of a select lever 16, showing the lever in a 1-2 gear range position 18 and a phantom outline 17 of the select lever 16 in a 3-4 gear range position 19. FIG. 6 shows a sectional view of the inhibitor 10 with the select lever 16 in the 1-2 gear range position 18 and a shift lever 20 in the neutral position 21. The sequence of shifting from neutral to first to second gear begins in FIG. 1 with the shift 20 lever in the neutral position 21 and the select lever 16 in the 1-2 gear range position 18. The inhibitor 10 does not restrict the positioning of the shift lever 20 here. This orientation of the elements occurs after the select lever 16 has been moved into the 1-2 gear range position 18 from another gear range position, such as the 3-4 gear range position 19. In FIG. 2 the shift lever 20 has been moved to the first gear position 22. In FIG. 3, the shift lever has been moved to the neutral position 21 on its way into the second gear position 23 shown in FIG. 4. When the shift lever is moved from the first gear position 22 to the neutral position 21, the shift lever 20 is linked to the select lever 16, thereby inhibiting movement of the shift lever 20 back toward the first gear position 22. FIG. 4 shows the shift lever 20 after it has been moved to the second gear position 23. Even when the shift lever 20 is linked to the select lever 16, there is no restriction in moving the shift lever 20 between the second gear position 23 and neutral. Rotating the shift lever 20 from the second gear position 23 to the neutral position 21 causes the relative orientation of the elements in FIG. 3 to be duplicated. The inhibitor 10 blocks any further movement of the shift lever 20 toward the first gear position 22. To shift into first gear, the select lever 16 must first be moved out of the 1-2 gear range position 18 to another gear range position such as the 3-4 gear range position 19 and then back into the 1-2 gear range position, returning the components to the orientation seen in FIG. 1. FIG. 6 shows a sectional side view of the inhibitor 10 and a shift shaft 24 interfacing with one type of gear selection/engagement means 26. The gear selection/engagement means 26 shown is similar to that shown in U.S. Pat. No. 4,174,644 to Nagy et al. on Nov. 20, 1979 and assigned to the assignee of this invention. The gear selection/engagement 26 means includes the shift shaft 24 and a shifter paddle 25 and gear engagement means 28, 30, and 32. The gear selection/engagement means 26 is used to select a desired gear range 34, 36, or 38 and to engage a desired gear (not shown) within the transmission housing. The gear ranges 34, 36, and 38 are the axial positions of the shift shaft 24 which permit engagement of a selected gear engagement means 28, 30, 32. For this embodiment, there is a 1-2 gear range 34, a 3-4 gear range 36, and a 5-R gear range 38. Gear range 34, 36, 38 selection is accomplished by axial positioning of the shift shaft 24 along a longitudinal axis 40 of the shift shaft 24. Engagement of gears (not shown) within the transmission housing 14 is accomplished by rotating the shift shaft 24 about the longitudinal axis 40 to displace the selected gear engagement means 28, 30, 32. The shift shaft 24 has a proximal end 42 which remains inside the transmission housing 14 and a distal end 44 which remains outside the housing 14. The transmission housing 14 rotatably supports the shift shaft 24, allowing the shift shaft 24 to both rotate and axially translate relative to the transmission housing 14. Each of the gear engagement means 28, 30, and 32 have a shift fork (not shown) and a pair of lugs 46, 48 and 50. The gap (not shown) between the lugs is a shift gate. The gear engagement means 28, 30, and 32 are positioned so that their respective lugs 46, 48, and 50 are located in close proximity to one another as seen in FIG. 6. The gear selection/engagement means 26 shown in FIG. 6 has the 1-2 shift gate lugs 46 on the bottom, the 3-4 shift gate lugs 48 in the middle, and the 5-R shift gate lugs 50 on the top. Only one of each pair of lugs 46, 48, and 50 for each gear engagement means 28, 30, and 32 are shown in the sectional view of FIG. 6 to illustrate the relationship of the lugs 46, 48, and 50 to the shifter paddle 25. The shifter paddle 25 is rotatively and axially fixed to the shift shaft 24. Each pair of lugs 46, 48, and 50 of the gear engagement means 28, 30, and 32 is disposed for engagement with the shifter paddle 25. Selection of the appropriate gear engagement means 28, 30, and 32 is made by moving the shift paddle 25 to the shift gate corresponding to the desired gear range 34, 36, 38. The shift paddle 25 is moved to the desired shift gate by rotating the select lever 16 to axially displace the shift shaft 24. Movement of the shift shaft 24 between gear ranges 34, 36, 38 can only occur with the shift lever 20 in the neutral position 21 where none of the gears are engaged. The neutral position 21 of the shift lever 20 is independent of the axial position of the shift lever 20 and the shift shaft 24. The neutral position 21 of the shift lever 20 and shift shaft 24 is their rotative position approximately midway between the first gear shift lever 22 position and the second gear shift lever position 23. Rotary displacement of the shift shaft 24 causes the shifter paddle 25 to displace the lug 46, 48, 50 contacted, thereby displacing the corresponding gear engagement means 28, 30, 32 and shifter fork (not shown), moving a corresponding gear (not shown) or sleeve (not shown) in the same direction. The shift lever 20 is rotatively mounted to the shift shaft 24, near the distal end 44 of the shift shaft 24. The shift lever 20 has a ball stud 54 mounted to it serving as means for connecting the lever 20 to a transmission shifter (not shown). A suitable shifter and connecting cables are shown in U.S. Pat. No. 4,143,560 issued Mar. 13, 1979 to Kinkade et al. and assigned to the assignee of this invention. A transmission shift shaft collar 56 is fixed to the transmission shift shaft 24 intermediate between the shift lever 20 and the transmission housing 14. The shift shaft collar 56 is annular in shape. As shown in FIG. 6, the collar 56 has an inside surface 58, an outside surface 60, a top side 62 and a bottom side 64. The inside surface 58 facilitates placement of the shift shaft collar 56 over the shift shaft 24 and fixing to the shift shaft 24. The collar 56 is fixed to the shift shaft 24 by a shear pin 66 which passes through aligned apertures 68 in both the collar 56 and the shift shaft 24. The pin 66 is retained by an interference with the aperture 68 in the shift shaft 24. The outside surface 60 is largely defined by a diameter concentric with the inside surface 58, but has an engagement channel 70 traversing the outside surface 60 equidistant between the top side 62 and the bottom side 64 for slidable engagement with a stub pin 72 of the select lever 16. There is also an engagement groove 74 in the outside surface 60 of the collar 56, from the top side 62 to the bottom side 64, located approximately opposite the engagement channel 70, for slidable engagement with a shift lever detent plunger housing 76. The shift shaft collar 56 also has an aperture 78 in the top side 62 for retaining a lower end 82 of a shift lever cam spring 80. The select lever 16 is rotatively mounted to the transmission housing 14. The stub pin 72 of the select lever 16 slidably engages the engagement channel 70 of the transmission shift shaft collar 56. When the select lever 16 is rotated, the stub pin 72 is arcuately displaced about a center of rotation 84 of the select lever 16. The stub pin 72 slidably translates across the engagement channel 70 of the collar 56 while slidably displacing the collar 56, and thereby the shift shaft 24, along the longitudinal axis 40 of the shift shaft 24. The select lever 16 also has a ball stud 86 as means for connecting the lever 16 to the transmission shifter (not shown). The select lever 16 also has a select lever detent plunger housing 88 formed integral with the select lever 16. The shift lever detent plunger housing 76 is fixed to the shift lever 20. The detent plunger housing 76 slidably engages the engagement groove 74 of the transmission shift shaft collar 56 parallel to the longitudinal axis 40 of the shift shaft 24. The detent plunger housing 76 imparts rotary motion to the shift shaft 24 with rotary movement of the shift lever 20. The housing 76 is tubular in shape with an inside diameter 90 and an outside diameter 92 as shown in FIG. 6. The housing 76 has an upper end 94 and a lower end 96. The upper end 94 of the detent plunger housing 76 is fixed to the shift lever 20. Disposition of a top detent plunger 98 and a bottom detent plunger 100 within the shift lever detent plunger housing 76 is accommodated by the inside diameter 90 of the detent plunger housing 76. The upper end 94 of the housing 76 is closed except for an orifice 102 to accommodate the passage of a nub 104 of the top detent plunger 98 through the upper end 94. The lower end 96 is open, accommodating installation of the detent plungers 98 and 100. The lower end 96 of the select lever detent plunger housing 88 has a slot 106 on the inside diameter 90 to accommodate a snap ring type retainer 108 for the detent plungers. The bottom detent plunger 100 is slidably disposed within the shift lever detent plunger housing 76. The bottom detent plunger 100 is tubular in shape, with an inside diameter 110 and an outside diameter 112. The bottom detent plunger 100 is open on an upper end 114 and closed on a lower end 116. The bottom detent plunger 100 also has a nub 118 on the lower end 116 which impinges against the select lever bracket 120 when the select lever 16 is placed in the 1-2 gear range position 18. The top detent plunger 98 is slidably disposed within the bottom detent plunger 100. The top detent plunger 98 is cylindrical in shape with an outside diameter 122 less than the inside diameter 110 of the bottom detent plunger 100. The top detent plunger nub 104 protrudes from the upper end 94 of the shift lever detent plunger housing 76 for engagement with an arcuate slot 124 in a bottom side 126 of a shift lever cam 128. A top detent plunger spring 130 is functionally interposed between the top detent plunger 98 and the bottom detent plunger 100 to sustain compressive loads between the plungers 98 and 100. The top detent plunger spring 130 is disposed within the inside diameter 110 of the bottom detent plunger 100. A bottom detent plunger spring 131 is functionally interposed between the shift lever detent plunger housing 76 and the bottom detent plunger 100 to sustain compressive loads between the plunger housing 76 and the bottom detent plunger 100. The spring 131 is disposed within the inside diameter 90 of the shift lever detent plunger housing 76. A bushing 132 retains and provides a centering pilot 134 for the shift lever cam 128. The bushing 132 is fixed axially and rotatively to the distal end 44 of the shift shaft 24. The bushing 132 is selectively removable from the shift shaft 24. A cam pin 136 is fixedly inserted in an orifice 138 in the bottom side 126 of the cam 128 as shown in FIG. 5. When the top detent plunger 98 of the shift lever 20 is disengaged from the cam 128, the cam 128 is positioned by an upper end 140 of the shift lever cam spring 80 pressing the cam pin 136 against the shift lever 20. A select lever detent plunger 142 is disposed within the select lever detent plunger housing 88. The select lever detent plunger 142 and the detent plunger housing 88 together engage a cam detent surface 144 of the shift lever cam 128 when the shift lever 20 has been in the first gear position 22 while the select lever 16 has been in the 1-2 gear range position 18. The shift lever cam spring 80 provides a torsional spring load to the cam 128 through the cam pin 136. The lower end 82 of the shift lever cam spring 80 is parallel to the longitudinal axis 40 of the shift shaft 24 and is inserted into the aperture 78 in the top side 62 of the shift shaft collar 56. The upper end 140 of the shift lever cam spring 80 extends out away from the shift shaft axis 40 in a plane perpendicular to the axis 40 for rotatably engaging the cam pin 136. The relationship between the cam 128 and the select lever detent plunger 142 can be seen in illustrations 1-5. They show how when the select lever 16 is in the 1-2 gear range position 18, the detent plunger 142 engages the cam 128. The shift lever cam 128 is mounted on the shift shaft 24 distal of the shift lever 20 and rotatively pilots on the bushing 132. The shift lever cam 128 is annular in shape with a central opening 148 of a constant diameter, providing a clearance fit to the bushing pilot 134. The cam 128 is rotatable about the longitudinal axis 40 of the shift shaft 24. The cam 128 has an outer wall 150 with the cam detent surface 144. The cam 128 also has an orifice 138 in the bottom side of the cam accommodating the fixed insertion of the cam pin 136. The arcuate slot 124 in the bottom side 126 of the cam 128 accommodates engagement with the nub 104 of the top detent plunger 98. This invention and the interrelationship of the parts can be more clearly understood by observing the sequence of operations of the device. On a shift into first gear from any other gear, except immediately following a 1-2 shift, the operation of the shift control 12 is much the same as with any conventional shift control. When, with the shift lever 20 in the neutral position 21, the select lever 16 is moved into the 1-2 gear range position 18 from another gear range position such as the 3-4 gear range position 19, the select lever detent plunger 142 impinges on the outer wall surface 150 of the cam as seen in FIG. 1. With the select lever 16 in the 1-2 gear range position 18, and the shift lever 20 in the neutral position 21, the cam 128 is not yet linked or engaged with the shift lever 20 by the top detent plunger nub 104. When the select lever 16 moves into the 1-2 gear range position 18, the bottom detent plunger 100 in the shift lever detent plunger housing 76 is pressed upward by contact with the select lever mounting bracket 120. The top detent plunger nub 104 is pressed upward against the bottom side 126 of the cam 128. The cam 128 is rotatively positioned relative to the shift lever 20 by contact of the upper end 140 of the shift lever cam spring 80 with the cam pin 136. The cam spring 80, when viewed from the distal end 44 of the transmission shift shaft 24, maintains a clockwise torque against the cam pin 136. The upper end 140 of the spring 88 is indexed counter clockwise relative to the bottom end of the spring 82 which in inserted in the top side 62 of the transmission shift shaft collar 56. The cam pin 136, and therefore the cam 128, are held rotatively fixed relative to the shift lever 20 by the clockwise torque provided by the spring 80. The shift lever 20 is rotated to the first gear position 22 causing the shifter paddle 25 to displace the lugs 46 on the gear engagement means 28, thereby displacing the gear engagement means 28, engaging first gear. As the shift lever 20 is moved counter clockwise into the first gear position 22, the cam 128 rotates with the shift lever 20 because of the contact between the cam pin 136 and the shift lever 20. As the shift lever 20 enters the first gear position 22, the select lever detent plunger 142 engages the detent surface 144 of the cam 128. When the shift lever 20 is in the first gear position 22, the cam 128 is located such that the select lever detent plunger 142 impinges on the cam detent surface 144. When engaged by the select lever detent plunger 142 and the detent plunger housing 88, the cam 128 is blocked from rotating in a counter clockwise direction and is restricted from moving in the clockwise direction by the select lever detent plunger 142. The clockwise restriction provided by the select lever detent plunger 142 impinging on the cam detent surface must be sufficient to prevail against a combination of both the torsional spring load of the shift lever cam spring 80 against the cam pin 136 and a frictional drag load on the cam 128 from the nub 104 of the top detent plunger 98 pressing against the bottom side 126 of the cam 128, so that the cam 128 will not be displaced in the clockwise direction as the shift lever 20 is moved from the first gear position 22 toward second gear. When the shift lever 20 reaches the neutral gear position as it is moved from the first gear position 22 to the second gear position as shown in FIG. 3, FIG. 5, and FIG. 6, the top detent plunger 98 is aligned with the counterclockwise end of the arcuate slot 124 in the bottom side 126 of the cam 128, allowing the top detent plunger nub 104 to travel up into the arcuate slot 124, engaging the shift lever 20 with the cam 128. As the shift lever 20 is moved into the second gear position it encounters no resistance from the inhibitor. The nub 104 travels along the arcuate slot 124 and the cam 128 continues to be held rotatively fixed by the select lever detent plunger 142. FIG. 4 shows the shift inhibitor 10, the select lever 16, and the shift lever 20 in their second gear positions. When the shift lever 20 is moved from second gear position back toward the first gear position 22, the top detent plunger nub 104 moves with the shift lever 20, traveling within the arcuate slot 124 in the bottom side 126 of the cam 128. The cam 128 continues to be rotatively engaged with the select lever 16 with the select lever detent plunger housing 88 blocking displacement of the cam 128 in the counter clockwise direction. The travel of the shift lever 20 is blocked at the neutral gear position by the nub 104 of the top detent plunger 98 reaching the counterclockwise end of the arcuate slot 124. The shift lever 20 is restrained from moving back into the first gear position 22. The orientation of the elements is the same as that shown in FIG. 3, FIG. 5, and FIG. 6. To release the inhibitor 10, allowing shifting into first gear, the select lever 16 must be rotated from the 1-2 gear range position 18 to the 3-4 gear range position 19 or the 5-R gear range position (not shown), thereby releasing the cam 128. When the select lever is moved from the 1-2 gear range position 18 to another gear range position, two things happen simultaneously to release the cam 128: first, the shift shaft 24 moves up as the select lever 16 is rotated, moving the shift lever 20 away from the transmission housing 14 and allowing the top detent plunger 98 to recede into the shift lever detent plunger housing 76 thereby disengaging the cam 128 from the shift lever 16, and second, the select lever detent plunger housing 88 allowing the cam 128 to once again freely rotate relative to the transmission housing 14. Once the cam 128 is fully released, the shift lever cam spring 80 again pushes the cam pin 136 against the shift lever 20, the same relative orientation of parts which this description began with, as seen in FIG. 1.

An inhibitor for a manual transmission shift control which aids in preventing unintended downshifts into first gear. The inhibitor blocks shifting from second gear to first gear following a first gear to second gear shift. No other shift sequence is affected.

[0001] This application is a National Stage completion of PCT/DE2009/050042 filed Aug. 11, 2009, which claims priority from German patent application serial no. 10 2008 041 374.7 filed Aug. 20, 2008. FIELD OF THE INVENTION [0002] The invention relates to an operating device for a gear shifting transmission, e.g. for a manual or automatic transmission having shift-by-wire actuation. BACKGROUND OF THE INVENTION [0003] Gear shifting transmissions of motor vehicles are generally shifted or controlled by means of an operating device disposed within reach of the driver. Actuating elements such as shift levers or selector levers are used regularly for this purpose, and are located, for example between the front seats of the motor vehicle or in other regions of the cockpit. [0004] In the case of mechanical transmission control or mechanical coupling between the selector lever and the gear shifting transmission—using a cable or linkage for example, the selector lever position always coincides with the actual transmission state due to the mechanical coupling. As a result, the driver can deduce, on the basis of the particular selector lever position, the current gear state of the transmission, and, then he can feel confident that the lever position coincides with the actual gear state of the transmission. [0005] However, when gear shifting transmissions are actuated electrically or using shift-by-wire, the actuating lever in the passenger compartment and the motor vehicle transmission in the engine compartment are no longer mechanically coupled in this manner. Instead, in the case of “shift-by-wire” transmissions, the shift commands are transmitted from the operating device to the motor vehicle transmission using electrical or electronic signals, and the shift commands are then implemented in the transmission using electrohydraulics, for example. Due to the absence of a mechanical connection between the transmission actuator system and the actuating lever, the transmission state, any shift interlocks, or impermissible shift commands can no longer impact the state of the actuating lever directly and noticeably for the driver. [0006] In by-wire actuated gear shifting transmissions, however, the absence of a mechanical connection between the transmission actuator system and the selector lever can, under certain basic conditions or in the case of an error, also lead to the selector lever position no longer coinciding with the gear state of the transmission. [0007] For example, modern automatic transmissions generally include a so-called “Auto-P” function, for example, that ensures that when the driver leaves the vehicle, the parking lock may possibly be engaged automatically in the transmission, for instance to prevent the unattended vehicle from rolling away if the driver failed to engage the parking lock before leaving the vehicle. In other words, the Auto-P function, which particularly can be automatically activated, when the ignition key is removed or the driver leaves the vehicle, ensures that the parking lock is automatically engaged in the transmission, regardless of the gear state that was actually selected using the selector lever. Thus, the parking lock would also be engaged automatically by the Auto-P function of the transmission or the vehicle if the driver had left the selector lever e.g. in the neutral position, in a tip gate that may be present, or in one of the gear selection positions. [0008] In this case however, the selector lever position does not coincide with the actual gear state of the transmission. When the driver returns to the vehicle or at the next attempt to start the vehicle, the position of the selector lever would therefore provide the driver visually and haptically with initially incorrect information. On the basis of his perception of the selector lever position, the driver would have to assume that the transmission is engaged in a neutral position, in the tip mode or in a gear selection position, although the transmission is actually engaged in the parking lock. This discrepancy between the selector lever position and transmission state could therefore lead to undesired operating errors or incorrect conclusions by the driver. [0009] The applicant's document, DE 10 2007 015 262 A1, discloses an operating device for a motor vehicle transmission having a device for selector lever return, which has an actuating device having a gear motor, with which the selector lever can automatically be returned from the manual shift gate (tip gate) into the automatic gate, or the selector lever can automatically be returned into the park lock position, for example. This known operating device is, however, associated with a certain design complexity in order to implement the desired actuating mobility of the selector lever, with the corresponding consequence of construction space and costs. It must also be expected that the electromotive drive and the reduction gear that are present there can generate disruptive noises. [0010] The same applies for the gear shift device for an automatic transmission known from DE 100 05 328 A1. In this gear shift device, a detent element connected to a selector lever is simultaneously in engagement with a notched contour and a ramp that is adjustable by a motor. By means of the ramp, the detent element can be brought out of engagement with the notched contour, and subsequently due to the incline of the ramp—together with the selector lever—can be automatically returned into a specific detent position. The motor or hydraulic drive of the ramp in this known device is, however, also relatively complex and requires considerable construction space. In the case of a drive using an electric gear motor noise problems are also to be expected. SUMMARY OF THE INVENTION [0011] Proceeding from this background, the problem addressed by the present invention is to create an operating device for a gear shifting transmission, with which the stated disadvantages found in the prior art can be overcome. The purpose of the invention is to reliably ensure that the selector lever position always reflects the actual gear state of the transmission, even with shift-by-wire-controlled gear shifting transmissions, for example in the case of the P-position, whereby reliable visual and tactile feedback about the actual gear state of the transmission can be realized. The invention is to prevent particularly that the selector lever, in the case of an automatically engaged park lock (“Auto-P”), remains misleadingly in the last engaged shift position. In contrast to the solutions known from the prior art, this functionality is to be implemented, however, with low design complexity, minimal construction space and without generating disruptive noises. [0012] In an initially known manner, the operating device according to the present invention comprises a housing base and a selector lever having a spring loaded detent element. The selector lever is movable back and forth between at least two detent positions or shift gates. Also in a known manner, the operating device further comprises a detent mechanism for locking the selector lever in the individual detent positions, wherein the detent mechanism has a notched contour for locking the selector lever and a bevel contour—having a corresponding incline with respect to the detent element—for automatically returning the selector lever into the first detent position. The detent element of the selector lever can be substantially simultaneously brought to overlap, or into engagement, with the notched contour and also with the bevel contour, and the notched contour and the bevel contour can be moved by actuation relative to each other in the direction of the selector lever detent element. [0013] According to the invention, the operating device is distinguished, however, in that the bevel contour is connected substantially rigidly to the housing base, whereas the notched contour can be moved back and forth relative to the housing base between a first position near the detent element and a second position away from the detent element. The notched contour is spring-loaded in the direction of the detent element of the selector lever, and in its first position overlaps the bevel contour such that the detent element of the selector lever in this position of the bevel contour is effectively in engagement only with the notched contour. Furthermore, the actuating device is formed by an actuator-controlled block for locking the notched contour in its first position near the detent element. The spring-loading of the displaceable notched contour is effectively weaker than the spring-loading of a detent element, and the first detent position of the notched contour (relative to the detent element of the selector lever in its first detent position) coincides with the first detent position of the bevel contour. [0014] Due to the simultaneous engagement of the detent element disposed at the selector lever in the two notched contours of the detent mechanism, and due to the actuating relative displaceability of the two notched contours, the two notched contours of the detent mechanism can thereby be brought into simultaneous, or selectively into engagement with the detent element of the selector lever. In particular, both notched contours of the detent mechanism—for the purpose of the normal operation of the selector lever—are displaceable relative to each other so that the bevel contour is mostly overlapped by the notched contour, that is, the detent element of the selector lever is in effective engagement only with the notched contour. This means that the detent element of the selector lever in any shift position of the selector lever locks into a corresponding indentation of the notched contour, and therefore the selector lever initially remains stable in the respectively selected position. [0015] However, if the selector lever now—e.g., in the case of Auto-P—is to be moved automatically back out of a shift position (or out of one of the shift gates) into the park lock position (or into the first shift gate), the notched contour can be moved for this purpose—relative to the bevel contour or relative to the housing base—so that the detent element of the selector lever is no longer in engagement with the notched contour, but instead is now in effective engagement with the bevel contour. Due to the incline of the bevel contour and the spring-loading of the detent element this leads to the detent element of the selector lever sliding on the bevel contour downward in the direction of the incline, whereby the selector lever is automatically set into motion, and only comes to rest in the position or the shift gate in which it corresponds to the appropriate first detent position of the bevel contour, or its lowest position. [0016] The constructively very simple representation of the automatic selector lever return that is the goal of the invention results because the bevel contour according to the invention is connected substantially rigidly to the housing base, whereas the notched contour is spring-loaded and disposed movable relative to the housing base—and thus also relative to the bevel contour connected to the housing base—and can be locked in its position near the detent element by means of an actuating block. [0017] Thus, according to the invention—for returning the selector lever into its first detent position—complex actuators, particularly, motors with gearing reduction or the like, are no longer necessary. Rather, the actuator for relative movement of the two notched contours can, due to the invention, be limited to simple locking of the movable notched contour in its position near the detent element. Thus, for returning the selector lever it is only necessary to release the locking of the movable notched contour by means of a simple actuator, whereupon the actual return movement of the selector lever can then occur due to the potential energy stored in the spring of the selector lever detent element. [0018] This is possible particularly because the spring-loading of the displaceable notched contour is effectively weaker than the spring-loading of the detent element at the selector lever, and also because the first detent position of the notched contour matches the first detent position of the bevel contour. Due to the effectively weaker spring-loading of the displaceable notched contour with respect to the selector lever detent element, the displaceable notched contour after releasing its locking is automatically disengaged by the spring-loaded detent element of the selector lever, and as a result the detent element comes into effective engagement with the bevel contour. Due to the incline of the bevel contour and due to the spring-loading of the detent element, this results in the return of the selector lever into the desired first lock position or first shift gate. [0019] If the selector lever has reached the desired first detent position or shift gate, that is, the detent element of the selector lever has arrived at the first detent position or at the lowest location of the bevel contour, then the displaceable notched contour, due to its spring-loading, can return again into its starting position because the first detent position of the notched contour in its starting position coincides, according to the invention, with the first detent position or with the lowest location of the bevel contour. [0020] The actuating block for locking the notched contour in the first position near the detent element is preferably formed by an armature of an electromagnet. In this manner, a constructively simple and robust representation of the actuator control of the displaceable notched contour is obtained. However, other actuators could be used just as well, for instance, linear drives, piezo elements, memory alloys, or electric motors, e.g., having locking cams. [0021] Further, the invention is implemented independent of how the spring-loaded detent element disposed on the selector lever is constructively formed, so long as the required simultaneous or parallel engagement into the notched contour and into the bevel contour can be guaranteed. According to a preferred embodiment of the invention, however, the selector lever has a substantially cylindrical or prismatic elongated shape having a substantially constant cross-section. The detent element is preferably formed as a spring-loaded detent roller. [0022] A substantially cylindrical or prismatic shape of the detent element is constructively easy to implement, and with it, can simply guarantee the simultaneous engagement in the notched contour and the bevel contour. The design of the detent element as a spring-loaded detent roller is advantageous in that only low frictional losses arise between the detent element and the notched contour or the bevel contour, whereby a reliable return of the selector lever into the desired first detent position or shift gate is guaranteed. [0023] The actuator system according to the invention is not limited to use of a selector lever with the change of detent positions, instead it can be used equally well—with an operating device having a plurality of shift gates—for an automatic lever return into a specific shift gate. Accordingly, in a further embodiment of the invention, the detent mechanism is designed for locking the selector lever into at least two shift gates. [0024] In a corresponding double design of the detent mechanism, a return through actuation of the selector lever into both a specific shift gate as well as into a specific detent position within a shift gate can be implemented. [0025] In a further embodiment of the invention, the actuator device comprises a crosspiece for guiding the selector lever, where a locking clip is disposed on the crosspiece. The locking clip can be locked to the housing base using a locking actuator. This way, the crosspiece, and with it, the selector lever can be locked in one of the detent positions or shift gates, whereby particularly shift interlocks, for instance shift lock, or blocking a change of shift gates into specific shift gates can be implemented in a simple manner, so that, for example, it is possible to switch into the manual tip gates only from the shift position “D” of the automatic gates, and not however from the shift positions “P”, “R” or “N”. [0026] Preferably the locking actuator is formed by the end of an armature of an electromagnetic actuator which can be brought to engage with the locking clip disposed on the crosspiece. The operating device particularly preferably comprises an electromagnetic actuator which serves both for locking the notched contour and for the locking engagement with the locking clip, and thus for blocking the selector lever in the first detent position or shift gate. [0027] The advantageous double function design of the electromagnetic actuator is attained in that both ends of the armature of the actuator are used functionally, in that the one end of the armature is designed for locking the notched contour and the opposite end of the armature is designed for locking engagement with the locking clip. [0028] Because the locking of the notched contour is only released through actuation if the selector lever is not located in the first detent position or shift gate, whereas the locking engagement of the armature, in contrast occurs only if the selector lever is located in the first detent position or shift gate, the double use of the common armature does not lead to undefined shifting states or undesired blocks of the shift lever. BRIEF DESCRIPTION OF THE DRAWINGS [0029] The invention is explained below in greater detail with reference to drawings that merely depict examples of embodiments. They show: [0030] FIG. 1 a schematic, isometric view of one embodiment of an operating device according to the present invention; [0031] FIG. 2 a crosspiece and detent mechanism of the operating device according to FIG. 1 in a view and representation corresponding to FIG. 1 ; [0032] FIG. 3 a schematic, isometric view of both notched contours and the magnet actuator of the detent mechanism, with activated notched contour; [0033] FIG. 4 the two notched contours and the actuator, with activated bevel contour in a view and representation corresponding to FIG. 3 ; [0034] FIG. 5 a schematic, isometric side view of the crosspiece, magnet actuator and locking clip of the operating device according to FIG. 1 to 4 ; and [0035] FIG. 6 the magnet actuator and the two notched contours of the operating device according to FIG. 1 to 5 in an enlarged representation and view corresponding to FIG. 5 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0036] FIG. 1 shows, in a schematic, isometric depiction one embodiment of an operating device according to the present invention. For better understanding and improved clarity, parts of the housing base 14 , the crosspiece 1 and the selector lever 2 are not shown in FIG. 1 . [0037] Here, the actuation lever or selector lever 2 can be seen mounted in a crosspiece 1 . The selector lever 2 , due to its mounting in the crosspiece 1 , can be moved about a first pivot axis 3 back and forth relative to the direction of travel 4 of the motor vehicle, while the crosspiece 1 together with the selector lever 2 can pivot laterally back and forth about a second pivot axis 5 . In this manner, the two degrees of freedom of movement of the selector lever 2 are defined—for example, within a typical shift pattern of a manual gear actuation, or in the shift pattern of an automatic transmission having an additional manual shift gate. [0038] The operating device according to FIG. 1 has two detent mechanisms. The first detent mechanism 6 , having a spring-loaded interlock pin 7 , serves for locking the selection lever 2 during movement forward or backward, relative to the vehicle, of the selector lever about the first pivot axis 3 , see vehicle direction 4 . In the embodiment shown, the first detent mechanism 6 is a monostable detent mechanism in which, in the absence of external forces, the selector lever 2 , due to the shape of the notched gate 8 , always returns again to its neutral central position along the vehicle direction 4 . [0039] The second detent mechanism 9 serves for locking the selector lever 2 in the transverse direction, in the case of sideways movements of the selector lever 2 about the second pivot axis 5 , that is, during shift gate changes of the selector lever 2 . [0040] The second detent mechanism 9 is shown again in FIG. 2 , together with the essential components of the crosspiece 1 . First, the crosspiece 1 can be seen, having the two pivot axes 3 and 5 . Further, a bearing element 10 in spring-loaded connection to the crosspiece 1 by means of a compression spring (not shown) and having a detent roller 11 mounted therein in a rotational manner, can be seen in FIG. 2 , as well as a notched contour arrangement comprised of the notched contours 12 and 13 . The arrangement of the two notched contours 12 and 13 is emphasized again very clearly in the FIGS. 3 and 4 . [0041] With lateral movements of the selector lever 2 and with it also, the crosspiece 1 , the bearing element 10 with the detent roller 11 pivots sideways—about the pivot axis 5 , in the opposite direction to the movements of the selector lever 2 —whereby the detent roller 11 moves into the area of the contours of the notched contour arrangement 12 and 13 and in the process contacts the respectively active notched contour of the two contours 12 , 13 . [0042] FIG. 3 shows in particular the manner in which the notched contour arrangement is composed of the two notched contours 12 and 13 . It can be recognized that the first notched contour 12 , which according to the invention represents the bevel contour 12 for returning the selector lever 2 into the first shift gate, is securely fastened to the housing base of the operating device (or to the actuator housing 14 , which here is formed integrally with the housing base of the operating device). In contrast, the second notched contour, which according to the invention forms the notched contour 13 for locking the selector lever 2 in the shift gates, is connected to the housing base or to the actuator housing 14 in a pivotable manner about the axis 15 according to FIGS. 3 and 4 . [0043] The notched contour 13 is spring-loaded by means of a coil spring 16 in the direction of its upper position, with respect to the drawing, and is additionally secured in this upper position by the end of an armature pin 17 of an electromagnetic actuator 18 , as shown in FIG. 3 . It can be seen that the bevel contour 12 in the relative position of the two notched contours 12 , 13 shown in FIG. 3 is overlapped by the notched contour 13 , whereby the detent roller 11 initially contacts only the notched contour 13 , and initially remains unaffected by the bevel contour 12 . [0044] This means, in other words, that in the relative position of the two notched contours 12 and 13 shown in FIG. 3 , normal, bistable locking of the detent roller 11 and with it, the crosspiece 1 as well as the selector lever 2 , occurs in the two shift gates of the represented operating device, so long as the notched contour 13 is located in the upper, locked position, relative to the drawing according to FIG. 3 . [0045] If in contrast, the selector lever 2 moves under actuator control out of the shift gate according to the representation in FIG. 1 and automatically returns into the other of the two shift gates of the represented operating device, then, the magnetic actuator 18 is activated for this purpose, whereby the armature pin 17 is pulled back, and the notched contour 13 is released. Because the coil spring 16 of the displaceable notched contour 13 is effectively weaker than the downward, relative to the drawing, acting spring-loading of the detent roller 11 or of the bearing element 10 , this leads to the enabling of the movement of the notched contour 13 by the then retracted magnet actuator 18 , leading to that fact that the notched contour 13 is pressed or pivoted downward, relative to the drawing, about its pivot axis 15 , due to the spring force of the spring-loaded detent roller 11 . [0046] This results in the changed relative position between the notched contour 13 and the bevel contour 12 , as shown in FIG. 4 . In this relative position of the notched contour 13 and the bevel contour 12 , the detent roller 11 interacts directly with the bevel contour 12 , whereas the locking effect of the notched contour 13 is temporarily suspended. [0047] Due to the spring-loading of the detent roller 11 , this leads to the fact that detent roller 11 glides along the incline of the bevel contour 12 , downward, and thus is deflected toward the left, relative to the drawing. As a result, the crosspiece 1 undergoes a rotation about the second pivot axis 5 (clockwise relative to the drawing), whereby the desired shift gate change of the selector lever 2 occurs automatically. [0048] Because the shape of the notched contour 13 at its first detent position coincides with the lowest position of the bevel contour 12 , when the notched contour 13 is located in its first position near the detent element (see FIG. 3 in the area of the dotted line), the notched contour 13 can, after completion of the shift gate change of the selector lever 2 , return automatically from its position according to FIG. 4 into the position according to FIG. 3 due to the spring effect of the coil spring 16 . Similarly, the armature pin 17 of the magnet actuator 18 , in the relative position of the notched contours 12 , 13 according to FIG. 4 still blocked in its retracted position, can return again into its starting position according to FIG. 3 , in which it again fixes the notched contour 13 in its upper position, relative to the drawing, near the detent element. Thus, immediately after the actuator triggered automatic shift gate change of the selector lever 2 , the normal operational readiness and locking of the operating device is restored. [0049] FIG. 5 shows the locking clip 19 , additionally present in this embodiment of the operating device, with which the selector lever 2 can be locked in the position of the first shift gate (see the dotted line in FIG. 3 ), e.g., in order to block under specific state conditions the change into the manual shift gate (for example, the selector lever in one of the “P”, “R” or “N” positions). The locking clip 19 , whose movable pivot connection to the crosspiece 1 by means of the pivot axis 20 is seen in FIG. 1 , comprises, for the purpose of locking, a bore in the extension of the armature pin 17 of the magnet actuator 18 , not visible in the figures. [0050] During activation of the magnet actuator 18 , not only is the notched contour 13 unlocked, as described above based on the description of FIGS. 3 and 4 , but simultaneously the rear end, relative to the FIG. 1 to 4 , of the armature pin 17 of the magnet actuator 18 , is deployed, see FIG. 6 . As a result, this end of the armature pin 17 can travel into the associated bore of the locking clip 19 , as soon as the actuating lever 2 , and with it the crosspiece 1 , are located in the position that coincides with the first shift gate (see dotted line in FIG. 3 ). Through this, the crosspiece 1 and actuating lever 2 —by means of engagement of the armature pin 17 in the locking clip 19 —are then locked in the first shift gate so long as the magnet actuator 18 remains activated, for example, as long as the selector lever is located in one of the positions “P”, “R” or “N”, for the case that the change into the manual shift gate is to be possible only from the selector lever position “D”. [0051] To facilitate and ensure the locking of the armature pin 17 of the magnet actuator 18 in the locking clip 19 , the end of the locking clip 19 is sloped, and the locking clip 19 is spring-loaded, and connected to the crosspiece 1 , pivotable about the pivot axis 20 according to FIG. 1 . In this manner, the locking clip can engage into the armature pin 17 even when the armature pin 17 is already deployed, when the actuating lever 2 and crosspiece 1 move out of the second shift gate back into the first shift gate. With the same effect, the armature pin 17 —instead of the locking clip 19 —can also be spring-loaded in a suitable manner, so that it can be initially displaced by the incline of the locking clip during the return movement of the crosspiece 1 , and subsequently can travel into the bore of the locking clip 19 . [0052] FIG. 6 shows again the unit comprised of the actuator housing 14 and bevel contour 12 assembled with the magnet actuator 18 and the notched contour 13 that is attached pivotably at the actuator housing 14 and bevel contour 12 . Here, the armature pin 17 of the magnet actuator 18 can be seen which is extended backwards and which in this position can travel into the above named bore of the locking clip 19 , and which this way locks the locking clip 19 and the crosspiece 1 connected to the locking clip 19 according to FIG. 5 in the first shift gate. [0053] As a result, it is clear that the invention creates an operating device with which the desired actuating positions or shift gate changes can be implemented with low design cost, with minimal construction space and at the same time also being nearly silent. The invention therefore contributes to the improvement of ergonomics and safety, as well as the efficient use of construction space, and cost effectiveness, in particular in the case of applications in the field of shift actuators of motor vehicles. LIST OF REFERENCE CHARACTERS [0000] 1 Crosspiece 2 Actuating lever, selector lever 3 Pivot axis 4 Direction of travel 5 Pivot axis 6 Detent mechanism 7 Interlock pin 8 Notched gate 9 Detent mechanism 10 Bearing 11 Detent roller 12 Bevel contour 13 Notched contour 14 Actuator housing, housing base 15 Pivot axis 16 Coil spring 17 Armature pin 18 Magnet actuator 19 Locking clip 20 Bearing axis

An operating device for shift-by-wire transmission comprises a selector lever which has a detent mechanism. The detent mechanism comprises bevel and notched contours that can be displaced for automatically returning the selector lever back to the first lock position or shift gate. The notched contour is spring-biased toward the selector lever detent element and overlaps the bevel contour in its first position, and an actuating block is provided for locking the notched contour in its first position near the detent element. The spring-loading of the notched contour is weaker than the spring-loading of the detent element, and the shape of the first detent position of the notched contour matches that of the first detent position of the bevel contour when the notched contour is located in the first position. The operating device enables actuator-controlled automatic return, and optional locking of the selector lever with little design effort, while simultaneously having low space requirements and minimal generation of any disturbing noise.

BACKGROUND OF THE INVENTION The present invention relates to moisture-curing, polyurethane hot-melt adhesive compositions based on polyethers. Hitherto hot-melt materials including eva, polyester or polyamide have been used for fast bonding processes and automatic adhesive application requiring quick setting bonds but these have usually been applied at temperatures of about 150°-200° C. For example, solvent-free reactive polyurethane hot-melt materials, such as are disclosed in German Specification DOS 2609266, solve the problem of high application temperatures by application of a low-viscosity hot melt at 100° C. which sets by crystallisation. Such adhesive systems exhibit good thermolytic and hydrolytic stability when chain-extended and cross-linked by atmospheric moisture. However, bonds provided by these crystallising polyurethane prepolymers have low elasticity before curing resulting in low initial peel strength immediately after bonding and have a lower setting rate which depends on the crystallisation rate of the polyester used. Other reactive crystalline polyurethane hot melts, such as the adhesive compositions disclosed in German Specification DOS 3236313, do show a better elasticity in the uncured state but have an undesirably high application temperature (approaching those of conventional hot-melt materials) and exhibit pot life problems at application. It is accordingly an object of the present invention to provide quick-setting, hot-melt adhesive compositions comprising polyurethane pre-polymers which have improved flexibility immediately after bonding whilst being heat stable and resistant to hydrolytic and chemical attack after curing. Our copending U.S. patent application Ser. No. 347124 filed May 4, 1989 now U.S. Pat. No. 4,999,407 describes and claims a quick setting, hot-melt polyurethane adhesive composition comprising a mixture of at least two amorphous polyurethane prepolymers, each polyurethane prepolymer providing a different glass transition point for said composition. Preferably the first polyurethane prepolymer has a glass transition point above room temperature and a second polyurethane prepolymer has a glass transition point below room temperature. These products are fast setting with high elasticity, even before curing. Polyethers such as polypropylene oxide, polyethylene oxide or polyoxybutylene have low glass transition temperatures and little if any crystallinity and thus do not seem to lend themselves to the preparation of hot-melt compositions. SUMMARY OF THE INVENTION According to the present invention a quick-setting, hot-melt polyurethane composition comprising a mixture of at least two polyurethane prepolymers is characterised by a first polyether-based polyurethane prepolymer having a glass transition point above room temperature and a second polymer or polyurethane prepolymer with a glass transition point below room temperature. Polyurethane prepolymers with Tg above room temperature may be prepared from low molecular weight polyethers (MW less than 1000) and polyisocyanates. Polyurethane prepolymers with Tg below room temperature may be prepared from high molecular weight polyethers, polyesters or polybutadienes and polyisocyanates. Preferably the second polyurethane prepolymer is also polyether based and prepared from high molecular weight polyether (MW greater than 1000) and polyisocyanates. A prepolymer with Tg above room temperature sets quickly on cooling down from the application temperature but gives a brittle bond at room temperature. A prepolymer with Tg below room temperature may be applied at a relatively low temperature, even as low as room temperature but the applied film tends to remain tacky and to remain elastic when cured. Such bonds are flexible down to the low glass transition point and little or no cohesion is observed before curing. A composition according to the present invention provides an optimisation of these two sets of properties, giving a fast-setting adhesive curing with atmospheric moisture to give flexible bonding over a wide temperature range. The compositions according to the present invention also avoid the hydrolytic degradation to which polyester polyurethanes are susceptible. Compositions according to the present invention may be prepared either by mixing two separately-prepared prepolymers or by a combined, one-shot procedure, depending on the polyols used. The first polyurethane prepolymer with a high Tg (above room temperature) is prepared from a polyether polyol and a polyisocyanate. The polyol has a molecular weight between approximately 200 and 1000, preferably 250 and 800, most preferably approximately 400. Prepolymers of such products have a Tg above room temperature if NCO/OH ratio is kept sufficiently low. Reducing molecular weight of polyols and NCO/OH-ratio of prepolymers increases the Tg of prepolymers. Such products require higher application temperatures, are faster setting and give bonds which are more brittle. Prepolymers based on typical chain extenders such as propylene glycol are not suitable for the present invention. The polyols used may be any type of polyetherpolyols such as polypropylene oxide, polyethylene oxide polyoxybutylene or copolymers. Polyethyleneglycol-based products are less suitable because of their high water absorption. The polyisocyanate is preferably an aromatic diisocyanate such as 4.4'-diphenylmethane- or 2.4'-toluenediisocyanate. Derivates with functionalities higher than two may also be used if NCO/OH-ratios for synthesis are kept sufficiently high. Aliphatic polyisocyanates can also be used but are generally found to be less suitable. The prepolymer with the high (above room temperature) glass transition point is prepared at a NCO/OH ratio of 1.1 to 2.0, preferably 1.15 to 1.5 and at temperatures above the application temperature of the final product, preferably between 80° and 140° C. For prepolymer synthesis, no catalyst is required but for faster curing of the final product any catalyst suitable for one part polyurethanes can be added in a quantity of 10-10,000 ppm, preferably 100-1000 ppm. For prepolymer synthesis from polyethers special stabilization is recommended. A variety of stabilizers like acids, β-dicarboxylic compounds and reactive isocyanates, as well as antioxidants, may be used. The polyurethane prepolymer with the low (below room temperature) glass transition point is also a reaction product of a polyol and a polyisocyanate. The polyol may be a linear or slightly branched polyether, polyester, polybutadiene or another OH-terminated polyol. Again polypropylene oxide, polyethylene oxide polyoxybutylene or copolymers are suitable polyethers and these have a molecular weight of more than 800, preferably more than 1000. Although polyether based polyurethanes are preferred, polyurethane prepolymers with Tg below room temperature based on polyesters or polybutadienes can be used for the present invention as well as non reactive polymers with low Tg like polyolefins and their copolymers, high molecular weight polyesters, polyethers or polyurethanes. Generally we prefer to use diols in the compositions of the invention, but the use of polyols with higher functionality can result in superior final bonding properties due to crosslinking facilities (for details see examples described hereafter). The polyisocyanate used to prepare the compositions of the invention is preferably an aromatic diisocyanate such as 4.4'-diphenylmethane diisocyanate or 2.4-toluene diisocyanate or derivates with functionality higher than two but aliphatic diisocyanates may also be used. The prepolymer is prepared at a NCO/OH ratio between 1.1 and 3, preferably 1.2 and 2.5 and at temperatures between room temperature and 140° C., preferably between 60° and 100° C. using stabilization as mentioned above, and with or without typical catalysts. The final product properties depend significantly on the types and mixing ratio of high and low Tg-prepolymers. If more prepolymer with high glass transition point is used, the adhesive is more viscous and initial strength is superior. Bonds are tougher but they are more inclined to be brittle at lower temperatures. By using more prepolymer with a lower Tg, the adhesive becomes less viscous, initial strength is lower and bonds are softer and more flexible. After application of the adhesive, the curing reaction with atmospheric moisture starts. Isocyanate reacts with water and carbon dioxide is formed. This often leads to unwanted foaming of the adhesive during curing. The degree of foaming depends on the quantity of carbon dioxide liberated, the reaction rate and the diffusion characteristics of the polymer system. The quantity of carbon dioxide can be controlled by NCO/OH ratio of prepolymers and molecular weight of polyols. The final product may also include usual and ingredients such as fillers, tackifying resins or plasticizers. The resulting mixture is usually transparent at room temperature and applied above the high Tg, preferably between 90° and 140° C. DETAILED DESCRIPTION OF THE INVENTION In order that the invention may be better understood preferred Examples will now be described in greater detail. EXAMPLE I Prepolymer A1 (Low Tg) 800 g (428 mVal) polypropylene oxide of molecular weight 4000 and 4.5 g toluolsulfonyl isocyanate are placed in a closed reactor at 60° C., 107 g (855 mVal) methylene diphenyl diisocyanate (MDI) are added and the temperature raised to 110° C. for two hours. 1.8 g dibutyl tin dilaurate (DBTL) are added and stirred for further 15 minutes at 110°-115° C. under vacuum. The prepolymer has a viscosity of 620 mPas at 130° C., a NCO-content of 406 mVal/kg and a glass transition point of approximately -60° C. Prepolymer B (High Tg) 351.3 g (2806 mVal) MDI are melted at approximately 40° C. in a closed reactor. 4.3 g toluolsulfonyl isocyanate and 500 g (2375 mVal) polypropylene oxide of molecular weight 400 are added. After heating one hour at approximately 60° C. and one hour at 120° C., 0.9 g DBTL are added and stirring at 120° C. is continued for 20 minutes. The prepolymer has a viscosity of 22 Pas at 130° C., a NCO content of 520 mVal/kg and a glass transition point of approximately +22° C. Formulation of Adhesive Composition (I) 93.7 g of the prepolymer A1 are added to 856.5 of the prepolymer B at 120°-125° C. and stirred for approximately one hour. The mixture is a colourless, transparent liquid at 130° C. with a viscosity of 12 Pas and a NCO-content of 485 mVal/kg. Differential Scanning Calorimetry (DSC) shows a glass transition point of approximately +7° C. The adhesive sets quickly and has good bond strength over a wide range of temperatures. (See the following tables). Foaming during curing is negligible if the thin layers of adhesive are applied. EXAMPLE II Prepolymer A2 (Low Tg) 80.4 g (642 mVal) MDI are melted at 44° C. 2.4 g toluolsulfonyl isocyanate and 400 g (257 mVal) polypropylene oxide (triol) added. The temperature is raised to 117° C. for approximately 1 hour. The prepolymer has a viscosity of 375 mPas at 130° C. and a NCO-content of 829 mVal/kg. Formulation of Adhesive Composition (II) 860.6 g prepolymer B from Example I are placed in a reactor at 130° C., 107.7 g prepolymer A2 are added and stirring is continued for 2 hours. The mixture is a colourless, transparent liquid at 130° C. with a viscosity of 12 Pas and a NCO content of 554 mVal/Kg. The adhesive sets quickly and has good bond strength over a wide range of temperatures. High temperature strength is improved (see following tables). Foaming is avoided by applying the adhesive thinly. EXAMPLE III Prepolymer A3 (Low Tg) 800 g (507 mVal) of an amorphous polyester from 1.6 hexane diol and a mixture of adipic acid and isophthalic acid with a molecular weight of 3500 sulfonyl isocyanate 4.6 g p-toluol are placed at 80° C. in a reactor with 127 g (1015 mVal) MDI are added under stirring and the temperature raised to 80° C. for 30 min and then to 127° C. for 45 min. After degassing under vacuum, a prepolymer A3 with a viscosity of 9 Pas at 130° C. and a NCO content of 555 mVal/kg is obtained. Formulation of Adhesive Composition (III) 855 g prepolymer B according to example I are placed in a reactor of 130° C. and 92.7 g prepolymer A3 are added and stirred for 1.5 hours at 130° C. The mixture is a colourless, transparent liquid at 130° C. with a viscosity of 20 Pas and a NCO content of 500 mVal/kg. The adhesive sets quickly and has good bond strength to a variety of plastics. (see following tables) Foaming during curing is avoided by applying the adhesive thinly. EXAMPLE IV (One-Shot Procedure) 500 g (2375 mVal) polypropylene oxide diol of molecular weight 400 and 90.2 g (48 mVal) of a polypropyleneoxide diol with molecular weight 4000 are placed in a closed reactor at 70° C. After addition of 4.8 g toluolsulfonyl isocyanate 368 g (2940 mVal) MDI is added under stirring. The temperature is raised to 105° C. and stirring is continued for 1 hour. 1.19 DBTL is then added and stirring is continued for 1 hour at 110° C. After degassing under vacuum, a prepolymer with viscosity of 6.8 Pas at 130° C. and a NCO content of 539 mVal/kg is obtained. The adhesive is colourless and transparent with good initial and final bonding properties. (see following tables) Foaming during curing is avoided by applying the adhesive thinly. TABLE 1______________________________________Initial Strength (measured after 10 minutes) Tensile shear strength Peel strength Wood canvas (N/mm.sup.2) (N/mm)______________________________________EXAMPLE I 1.8 2.8EXAMPLE II 1.0 3.0EXAMPLE III 1.5 0.8EXAMPLE IV 0.6 1.5______________________________________ TABLE 2______________________________________Final Bond Strength Tensile shear strength (wood) (N/mm.sup.2) r.t. 100° C. 150______________________________________EXAMPLE I 7.8 1.6 1.3EXAMPLE II 8.4 1.9 1.4EXAMPLE III 10.2 0.8 0.7EXAMPLE IV 8.8 not determined______________________________________ TABLE 3______________________________________Hydrolysis ResistanceTensile shear strength of beechwood bonds after hydrolysisB 4/10-test according to DIN 68602 (six hours boilingwater, seven days drying at room temperature)______________________________________ EXAMPLE I 7.7______________________________________ The adhesive composition of Example I was assessed for resistance to hydrolysis by measuring tensile shear strength of beechwood bonds after hydrolysis. The assessment was carried out by the B4/10 test according to DIN 68602 and the tensile shear strength measured after six hours in boiling water followed by seven days drying at room temperature. The results showed a tensile shear strength of 7.7 N/mm 2 .

A quick-setting, moisture-curing hot-melt polyurethane composition having a first polyether-based polyurethane prepolymer having a Tg above room temperature and a second polyurethane prepolymer with a Tg below room temperature, the first prepolymer being prepared from a low molecular weight polyether; preferably the second prepolymer is also polyether based and prepared from a high molecular weight polyether.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an alarm management system. More particularly, the invention relates to a system and method for managing alarms in an industrial facility. Even more particularly, the present invention relates to a system and method for managing a plurality of alarms in a nuclear power plant. 2. Description of Related Art Day to day operations in most industrial facilities, including nuclear power generation plants, are typically uneventful. However, certain unscheduled events may occur that require the immediate attention of operational personnel. Thus, most process parameter monitoring systems are designed to include some type of warning system to alert operational personnel to an impending, or current, event requiring their attention. More specifically, these systems typically sound an audible alarm to alert operational personnel that a process parameter has exceeded a specified limit. Some unscheduled events may result in numerous alarms being sounded. These alarms may come from different systems, require differing levels of attention, and require attention by different operational personnel. Thus, when multiple alarms sound simultaneously or in momentary succession, operational personnel must determine what system each alarm is associated with, the priority level of each alarm, and which operator is responsible for attending to each alarm. This may result in confusion, missed alarms, inattention to certain alarms, or a combination of all of these factors, especially if the alarms are spread out around the facility. Designers have attempted to alleviate the above-mentioned factors to some extent in the nuclear power plant context. Specifically, modern nuclear power plants utilize a centralized control room design having computer-based workstations to allow convenient access to plant controls and functions from a single location. The workstations are divided into assigned operational responsibilities. For example, the reactor operator workstation encompasses controls and functions associated with reactor operations (e.g., primary plant systems including the nuclear reactor), and the turbine operator workstation encompasses controls and functions associated with secondary plant operations (e.g., steam plant systems). When one or more alarm situations occur, an alarm system outputs an audible tone to alert the control room operators. The system further causes the alarms to be depicted on workstation video display units as alarm lists, or highlighted on system mimic diagrams. The alarm lists may be filtered by certain categories such as by alarm priority or by the system in which the alarms occur. However, even modem centralized control room designs exhibit certain deficiencies. Specifically, when an audible tone is generated upon occurrence of a new alarm, the operators must manually determine which operator has responsibility for the alarm. This is accomplished by manually scanning an alarm list to determine if the new alarm is associated with the reactor operator or the turbine operator. Or, the control room operators must examine the various system mimic diagrams on the video display units to make the determination. Both of these operations are time consuming and distracting. Additionally, while the alarm lists may be filtered by certain categories, there is no coherent alarm status overview that allows an operator to conveniently observe the overall alarm-state of the plant and how the alarms are distributed. An operator can readily determine individual alarms and groups of related alarms using the category filtering function, but it is difficult to ascertain the overall plant alarm-state and determine the distribution of the alarms. Finally, present alarm systems provide no implementation that supports direct access to an operator's desired view of one or more alarms from a high-level plant alarm status overview. For example, an operator may wish to observe a new alarm from different perspectives, such as from an alarm list or from within a system mimic diagram to observe the context of the alarm relative to associated plant components and systems. With present alarm systems, an operator must either manually search through a display menu to select the desired system mimic diagram or manually recall an appropriate alarm list. Thus, there is a need for an alarm annunciation system that notifies operators immediately, upon the occurrence of one or more alarms, which operator has responsibility for each alarm. There is also a need for an alarm distribution indication system that presents a coherent view of the current plant alarm-state and the distribution of alarms by operator responsibility, priority, and system. There is additionally a need for a device for selectively displaying alarms that supports direct access to an operator's desired view of one or more alarms from a high-level plant alarm status overview. Finally, there is a need for an entire alarm management system that incorporates each of these features. SUMMARY OF THE INVENTION In one aspect of the present invention, an alarm management system comprises receiving means, comparing and generating means, receiving and transmitting means, and sound generation means. The receiving means receives one or more process parameter signals representative of one or more process parameters. The comparing and generating means compares each of the received process parameter signals with an associated alarm setpoint and generates an alarm status signal on the basis of the comparison. The receiving and transmitting means receives the alarm status signal and transmits an annunciation command signal on the basis of the received alarm status signal. The sound generation means generates a sound on the basis of the annunciation command signal. In another aspect of the present invention, an alarm annunciation system comprises receiving and transmitting means, tone generation means, and voice synthesization means. The receiving and transmitting means receives an alarm status signal and transmits an annunciation command signal on the basis of the received alarm status signal. The tone generation means generates a plurality of tones, each having a different frequency from another, on the basis of the annunciation command signal. The voice synthesization means synthesizes a human voice signal of a specified pitch on the basis of the annunciation command signal. In still a further aspect of the present invention, an alarm distribution indication system comprises memory means, information extraction means, information categorization means, and display means. The memory means stores alarm information of a plurality of alarms. The information extraction means periodically extracts the alarm information from the memory means. The information categorization means categorizes the extracted alarm information into to a plurality of predetermined categories. The display means displays the alarm information, for each of the plurality of alarms, arranged into the plurality of predetermined categories. In yet another aspect of the present invention, a device for selectively displaying a plurality of alarms, comprises a video display unit, an input selection device, information storage means, information categorization means, mimic display storage and generation means, and information transfer means. The information storage means stores alarm information for each of the plurality of alarms. The information categorization means periodically retrieves and categorizes the stored alarm information into a plurality of predetermined categories. The mimic display storage and generation means stores mimic display information for a plurality of process systems, and periodically retrieves the stored alarm information and generates the mimic display information for each of the plurality of process systems including the retrieved alarm information therein. The information transfer means receives a first command from the input selection device to select information and transfers the selected information to the video display unit for display thereon. The selected information includes one of the alarm information in one of the first plurality of predetermined categories, and the alarm information included in one of the plurality of process system mimic displays. In yet still a further aspect of the present invention, a method of managing a plurality of alarms includes the steps of receiving, comparing, generating an alarm status signal, receiving the alarm status signal, transmitting an annunciation signal, and generating a sound. In the receiving step, one or more process parameter signals representative of one or more process parameters are received. In the comparing step, each of the received process parameter signals is compared with an associated alarm setpoint. In the alarm status signal generating step, an alarm status signal is generated on the basis of the comparison in the comparison step. The alarm status signal is received in the alarm status signal receiving step. An annunciation command signal is transmitted on the basis of the received alarm status signal, in the annunciation command signal transmission step. A sound is generated on the basis of the annunciation command signal, in the sound generation step. The present invention provides distinct features and advantages over related alarm management systems and components. Specifically, an alarm annunciation system directs attention to the appropriate operational personnel whenever a new alarm is generated, or when an existing alarm condition returns to normal. Thus, operators are not required to manually determine which operator is responsible for the alarm. An alarm distribution indication system provides a single display page on a video display unit from which operators can conveniently ascertain the overall alarm state and alarm distribution. Thus, operators do not have to mentally construct an overview of the overall alarm state and distribution by examining and filtering various alarm lists. Additionally, a device for selectively displaying a plurality of alarms allows operators to conveniently and rapidly access one or more alarms based on a desired contextual view. Thus, operators do not have to manually search through a display menu to select a desired mimic display or manually recall the appropriate alarm list. These and other features and advantages of the present invention will become more apparent to those skilled in the art when the following detailed description is read in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic representation of an alarm management system according to the preferred embodiment of the present invention. FIG. 2 depicts a display page showing an alarm status overview that may be viewed on a workstation video display unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The alarm management system 10 , depicted schematically in FIG. 1, receives signals from one or more sensors 12 . The sensors 12 provide signals indicative of various process parameters within the industrial facility into which the system 10 is installed. In this regard, the term process parameter refers to physical parameters, such as temperature, pressure, flow rates, etc., and also refers to plant component status, such as valve positions, pump rotation speeds, vibration levels, etc. The skilled artisan will appreciate that the number of process parameters, and the specific physical parameters and component statuses, will vary according the application with which the alarm management system 10 is being used. The skilled artisan will further appreciate that various types of sensors known in the art may be used with the present invention. The signals provided from each sensor 12 are transmitted to a data acquisition system 14 , which may be any conventional data acquisition system known in the art. The sensor data is then transmitted from the data acquisition system to a digital computer 16 . The digital computer 16 may be a personal computer (PC), a plurality of networked computers, or a main frame computer. A plurality of alarm video display units 26 are located at operator workstations to display alarm information to operators. The number of alarm video display units 26 will depend upon the number of operators necessary for the particular plant. However, in the preferred embodiment, for a nuclear power plant, the number of workstations and alarm video display units 26 is two, one for the reactor operator and one for the turbine operator. Each operator workstation also includes an operator input device 28 , which allows the workstation operator to interface with the digital computer 16 . The operator input device 28 may be a trackball, a computer mouse, a touch-screen, a finger-pad, or any other device known to the skilled artisan. The operator input device 28 is used to acknowledge new alarms and clear alarms that have returned to normal. The operator input device 28 is also used to transmit a “link request,” discussed further below, to selectively display the alarms in a particular format on the associated alarm video display unit 26 . The alarm video display units 26 and operator input devices are connected to the computer 16 via a network connection 15 . The network connection 15 may a dedicated network connection or shared with other systems. Several modules within the computer 16 interact to achieve the desired functionality of the present invention. These modules may be separately designed individual hardware modules, conventional hardware modules programmed to perform specified functions, or may represent software modules which cause the digital computer 16 to perform each of the specified functions. The modules may be grouped into three main subsystems, all of which interact directly or indirectly with an alarm processing module 18 . These subsystems shown using dotted lines in FIG. 1, are a directive annunciator subsystem 30 , an alarm distribution overview indicator subsystem 40 , and an alarm view linker subsystem 50 . It should be noted that the alarm video display units 26 and operator input devices 28 , which are located at each workstation, are common to both the alarm distribution overview indicator subsystem 40 and the alarm view linker subsystem 50 . It should further be noted that these subsystems share certain functional modules and information when integrated together into a system, though each are described herein as separate subsystems. These facts will become apparent from the description of each of these subsystems provided below. It will be further appreciated by the skilled artisan that each of these subsystems could be utilized alone, or in any desired combination, to achieve a desired functional result. In the following description, a description of the operation of the alarm processing module 18 will be provided, followed by a detailed description of each of the subsystems. Alarm Processing Module The alarm processing module 18 compares the sensor data received from the data acquisition system 14 to associated alarm setpoints and generates appropriate alarm status signals on the basis of the comparison. The particular alarm status signal generated by the alarm processing module 18 will depend upon whether a datum exceeds a setpoint (a new alarm condition), or a datum that previously exceeded a setpoint is now below the setpoint (a return-to-normal condition). The alarm status signal generated by the alarm processing module 18 also includes various types of classification information to assist operators. This information includes the alarm priority classification, the operational responsibility classification, and the plant system classification. The priority classification information alerts the operator (or operators) to the relative importance of the alarm. Thus, an operator can readily distinguish between relatively important and unimportant alarms, and thereby prioritize recovery actions to minimize operational impact. The number of priority classifications can be varied to suit the particular use, but in the nuclear power generation context, the preferred number of priority classifications is three. In this respect, the priority classifications are labeled “Priority 1 ,” “Priority 2 ,” and “Priority 3 .” Priority 1 alarms are the last, and sometimes only, warning prior to reaching a “Significant Operator Action” condition. These alarms are generally related to the safety and availability of the plant, and include conditions associated with violations of critical reactor safety functions. If such conditions are not corrected immediately, a plant shutdown (manual or automatic), a radioactive release, or major equipment damage, will result. Priority 2 alarms are the next to last warning prior to reaching a “Significant Operator Action” condition. These alarms include conditions associated with plant technical specification violations that, if not corrected, will result in an eventual plant shutdown, or an eventual radioactive release. Priority 3 alarms are warnings prior to the next to the last warning before reaching a “Significant Operator Action” condition. If no significant operator action can result, these alarms are the only warning. Priority 3 alarms include conditions that, if left unattended, could result in a subsequent higher priority alarm condition. Such conditions typically indicate equipment or process anomalies. The operational responsibility classification indicates which operator is responsible to process the alarm. The number of operational classifications can also include any number necessary to meet the requirements of the environment in which the system is being employed. In the nuclear power generation context, however, the preferred number of operational responsibility classifications is two. These classifications are the reactor operator (RO) classification and the turbine operator (TO) classification. Thus, an alarm in the RO classification indicates that the reactor operator is responsible to process the alarm, and an alarm in the TO classification indicates that the turbine operator is responsible. The plant system classification indicates which plant system the alarm is associated with. Again, the number of system classifications can vary with the application. In the nuclear power generation context, the plant system classification would include, for example, the Chemical and Volume Control System, Reactor Coolant Pumps, Reactor Core, Main Feedwater System, Auxiliary Feedwater System, etc. The alarm processing module 18 also includes logic to suppress temporary alarms that occur due to plant transients or other momentary disturbances. These temporary alarms are not necessary for safe operation and are considered to be nuisance alarms since they do not reflect actual process parameter abnormalities. Directive Annunciator Subsystem The directive annunciator subsystem 30 is comprised of an annunciator logic module 32 , a tone generator 34 , a speech synthesizer 36 , and a speaker 38 . The directive annunciator subsystem 30 interacts with other components and subsystems to provide audio notification of new alarm conditions, and return-to-normal conditions. The audio notification also provides appropriate operator responsibility classification information to operators. Specifically, whenever the alarm processing module 18 determines that a new alarm condition or a return-to-normal condition exists, the alarm processing module 18 sends an updated alarm status signal to the annunciator logic module 32 . The annunciator logic module 32 receives the alarm status signal, and the information contained therein, to determine an appropriate audio output command for the specific condition. The appropriate audio output command is sent to both the tone generator 34 and the speech synthesizer 36 , via the network 15 . The tone generator 34 produces a plurality of alarm tones of differing frequencies to alert the operator to a new alarm condition, a return-to-normal condition, or to alert the operator that a new alarm has not been acknowledged. The speech synthesizer 36 generates voice messages to direct attention to the proper operational responsibility for both a new alarm condition and a return-to-normal condition. As with the tone generator 34 , voice messages of differing frequencies are used to differentiate between the operational responsibility for the alarm. The voice frequencies generated by the speech synthesizer 36 can be selected based on the desired effect and number of differing operational responsibility categories. In the preferred embodiment, however, where the system is used in a nuclear power plant, two different voice frequencies are used. A substantially male sounding voice is used for reactor operator responsibility alarms, and a substantially female sounding voice is used for turbine operator responsibility alarms. The operation of the directive annunciator subsystem will be explained below for various exemplary conditions. If the alarm processing module 18 determines that a new alarm condition exists, it sends an appropriate signal to the annunciator logic module 32 . The annunciator logic module 32 then sends appropriate commands the tone generator 34 and the speech synthesizer 36 . The tone generator 34 then generates a momentary tone (e.g., approximately 1 second in duration), to alert the operators to the new alarm condition. Immediately thereafter, the speech synthesizer 36 generates an appropriate sounding voice message directed to the appropriate operator. In the preferred embodiment, if the responsible operator is the reactor operator, the voice message would be a substantially male sounding voice stating, “New reactor alarm(s).” If the responsible operator is the turbine operator, the voice message would be a substantially female sounding voice stating, “New turbine alarm(s).” Moreover, if several new alarms occur simultaneously, some being the reactor operator's responsibility and some being the turbine operator's responsibility, the voice message would state, “New reactor alarm(s) and new turbine alarm(s).” In this instance, a substanatially male sounding voice is used for the former part of the message (e.g., “New reactor alarm(s)”), and a substantially female sounding voice for the latter part (e.g., “and new turbine alarm(s).”). Upon receipt of the tone and voice message, the appropriate operator can then view the alarm(s) on the associated alarm video display unit 26 , and use the operator input device 28 associated with the workstation to acknowledge the alarm. The operator can then take appropriate action. When the operator acknowledges the new alarm using the operator input device 28 , the alarm information in the current alarm file 42 is updated to reflect this acknowledgement. If the alarm processing module 18 determines that one or more return-to-normal conditions exist, it sends an appropriate signal to the annunciator logic module 32 . The annunciator logic module 32 in turn commands the tone generator 34 and speech synthesizer 36 to generate an appropriate tone followed by an appropriate voice message, respectively. Specifically, a tone different from the new alarm condition tone is momentarily generated (e.g., for approximately 1 second) by the tone generator 34 . Then, the voice synthesizer 36 outputs a voice message of appropriate frequency. For instance, in the preferred embodiment of the invention, if the return-to-normal condition is associated with a reactor operator responsibility alarm, the voice message would be a substantially male sounding voice stating, “Cleared reactor alarm(s).” Likewise, if the return-to-normal condition is associated with a turbine operator responsibility alarm, the voice message would be a substantially female sounding voice stating, “Cleared turbine alarm(s).” Finally, if the return-to-normal condition is associated with a plurality of alarms, some being associated with the reactor operator's responsibility and some being associated with the turbine operator's responsibility, the voice message would state, “Cleared reactor alarm(s) and cleared turbine alarm(s).” Again, in this instance a substanatially male sounding voice is used for the former part of the message (e.g., “Cleared reactor alarm(s)”), and a substantially female sounding voice for the latter part (e.g., “and cleared turbine alarm(s).”). Upon receipt of the tone and voice message, the appropriate operator can then use the operator input device 28 associated with the workstation to clear the alarm. When the operator clears the alarm, the alarm information in the current alarm file 42 is updated to reflect that it is cleared. As noted above, upon receipt of a new alarm condition or a return-to-normal condition, as appropriately annunciated by the new alarm tone and voice message, the operator uses the operator input device 28 to acknowledge the alarm or the return-to-normal condition. If either condition is not acknowledged within a predetermined period of time, the directive annunciator subsystem 30 provides a reminder notification to the operator. To generate the reminder notification, the alarm processing module 18 periodically scans the information in the current alarm file 42 to determine if any alarm conditons have not been acknowledged or return-to-normal conditions have not been cleared. If either of these conditions exists, the alarm processing module 18 directs an appropriate alarm status signal to the annunciator logic module 32 . The annunciator logic module 32 then commands the tone generator 34 and voice synthesizer 36 to generate an appropriate tone and voice message, respectively. Specifically, a momentary tone having a unique frequency, would be followed immediately by an appropriate voice message. For instance, in the preferred embodiment, for unacknowledged alarms or uncleared (return-to-normal) conditions associated with reactor operator responsibility, the voice message would state, “Unacknowledged (Uncleared) reactor alarm(s).” For unacknowledged alarms or uncleared (return-to-normal) conditions associated with turbine operator responsibility, the voice message would state, “Unacknowledged (Uncleared) turbine alarm(s).” And, for a plurality of unacknowledged (uncleared) alarms, some being associated with the reactor operator's responsibility and some being associated with the turbine operator's responsibility, the voice message would state, “Unacknowledged (Uncleared) reactor alarm(s) and unacknowledged (uncleared) turbine alarm(s).” Once again, in this instance a substanatially male sounding voice is used for the former part of the message (e.g., “Unacknowledged (Uncleared) reactor alarm(s)”), and a substantially female sounding voice for the latter (e.g., “and unacknowledged (uncleared) turbine alarm(s).”). If new alarms occur before a previous alarm is acknowledged, the new alarm will be initially annunciated with the appropriate tone and voice message. The reminder tone will be periodically output thereafter until all unacknowledged alarms have been acknowledged. The similar function occurs if new return-to-normal conditions occur before previous ones are cleared. Alarm Distribution Overview Indicator The alarm distribution overview indicator subsystem 40 comprises the current alarm file 42 , an alarm status overview module 44 , and one or more alarm video display units 26 . The alarm distribution overview indicator subsystem 40 interacts with other subsystem modules to provide a coherent status overview of overall alarm status. In other words, how the alarms are distributed. This function of this subsystem will now be described. The alarm status overview module 44 periodically searches through the alarm information stored in the current alarm file 42 . The search periodicity is not critical to the inventive concept, but in the preferred embodiment it is approximately every second. The stored information includes the alarm status information (e.g., whether the alarm is new; whether the alarm, if new, has been acknowledged; and whether the alarm has returned-to-normal). And, as discussed previously, the stored information also includes the information associated with the each alarm's priority classification, operational responsibility classification, and plant system classification. The alarm status overview module 44 , during the search period, extracts the information and arranges it according to both its status and classification. The information so arranged by the alarm status overview module 44 is then sent to one or more of the alarm video display units 26 . An exemplary display page 60 view of the alarm status overview that a alarm video display unit 26 would provide is illustrated in FIG. 2 . An operator viewing this display page 60 is presented with an overall alarm distribution summary, according to each alarm's status and its specific operational responsibility (or “Work Scope”), alarm priority, and system classifications. Thus, within each of the specific classifications, the display page 60 depicts the number of alarms that are new, acknowledged, and returned-to-normal. The display page 60 also depicts the total number of alarms that are new, acknowledged, and returned-to-normal. As shown in the right-hand portion of FIG. 2, the display page 60 also depicts various links 62 . These links 62 are used with the alarm view linker subsystem 50 . The alarm view linker subsystem 50 interacts with other subsystem modules and allows an operator to directly link, from the display page 60 , to a desired alarm view. Thus, the operator can view alarm information from various perspectives. Specifically, the operator can view the alarms from a system mimic diagram display perspective, or an alarm list perspective. Alarm View Linker The alarm view linker subsystem 50 comprises a link module 52 , an alarm list generator module 54 , a VDU display set module 56 , and one or more workstation alarm video display units 26 and associated operator input devices 28 . Using the operator input device 28 , an operator makes a “link request” for a specific alarm view by designating the appropriate link 62 . For example, if the operator input device 28 is a touch-screen, and the operator wishes to view a list of alarms having a Priority I classification, the operator would touch the display page 60 at the link 62 displaying “P- 1 .” Or, if the operator wishes to view alarms associated with a particular system on a system mimic diagram, the operator would touch the display page at the link 62 under the Mimic Display column displaying the particular system designation. The link module 52 recognizes the link request made by the operator, via the operator input device 28 , and outputs the appropriate view, either a list or system mimic diagram display, to the associated alarm video display unit 26 . The link module 52 retrieves the desired information for display from the alarm list generator module 54 for alarm list display links, or from the VDU display set module 56 for system mimic diagram display links. The alarm list generator module 54 periodically retrieves the alarm information stored in the current alarm file 42 and generates a series of lists. Each list contains a chronological listing of each alarm within the selected alarm list classification, and includes specific and detailed information about the alarm condition. More specifically, the alarm list generator module 54 generates separate lists for each operational responsibility classification, each priority classification, each system classification, and a total alarm list. For example, according to the preferred embodiment, wherein the system is installed in a nuclear power plant, the alarm list generator module 54 generates the following lists: RO Alarm List, TO Alarm List, ALL Alarm List, Priority 1 Alarm List, Priority 2 Alarm List, Priority 3 Alarm List, and various SYSTEM Alarm Lists. The RO and TO Alarm Lists contain, respectively, a chronological listing of all RO and TO alarms (both new and acknowledged) and RO and TO alarms that have returned-to-normal (but not yet cleared). These lists can be further filtered, via the operator input device 28 , to indicate, respectively, only the new (unacknowledged) RO and TO alarms, only the RO and TO alarms that have returned-to-normal but have not been cleared, or only the RO and TO alarms that have returned-to-normal by alarm priority level. With the latter filtration, Priority 1 alarms are listed first in their chronological order of occurrence, followed concomitantly by Priority 2 alarms then Priority 3 alarms. It should be noted that this filtration scheme is not limiting and other filtration schemes can be used to display various subsets of the RO and TO alarm lists. The ALL Alarm List contains alarm information similar to that described for the individual RO and TO alarm lists, including the specified filtration scheme. However, this list contains the total number of alarms, regardless of operational responsibility. The Priority 1 , 2 , and 3 Alarm Lists contain, respectively, a chronological listing of all Priority 1 , 2 , and 3 alarms (new and unacknowledged) and Priority 1 , 2 , and 3 alarms that have returned-to-normal, regardless of operational responsibility. These lists may be further filtered, via the operator input device 28 , to indicate, respectively, the Priority 1 , 2 , and 3 alarms associated with either the RO and/or the TO. The SYSTEM Alarm Lists each contain a chronological listing of all alarms associated with a particular system. Since each system is typically associated with either the RO or the TO, the operational responsibility information is inherently contained within each list. However, certain systems do have alarms that fall under the operational responsibility of both the RO and TO. For such systems, the particular SYSTEM Alarm List may be further filtered accordingly. The VDU display set module 56 stores all of the mimic diagram displays associated with each system. The system mimic diagram displays are organized in a hierarchical order, and contain alarm information graphically depicted in the context of plant systems, components, and processes. Similar to the alarm list generator module 54 , the VDU display set module 56 periodically retrieves the alarm information from the current alarm list module 42 , and updates the mimic diagram displays accordingly. The VDU display set module 56 includes color coding, shape coding, and dynamic behavior (such as blinking) to indicate the presence of alarms and to indicate the alarm state (i.e., new alarms, acknowledged alarms, returned-to-normal alarms). For example, alarms that appear on a system mimic diagram display as an alphanumeric value will change from a “normal value” color to the “alarm value” color at the point in the system mimic diagram where the alarming parameter is being monitored. If the specified alarm has a dynamic alarm behavior associated with it, such as blinking, this behavior will also be depicted on the system mimic diagram display. Additionally, if a particular component in a system is controlled when an alarm condition occurs, such as a pump or a valve, the component symbol on the system mimic diagram display will be depicted with the appropriate alarm condition color, shape, and/or dynamic behavior. While preferred embodiments of the present invention have been illustrated in detail, it is apparent that modifications and adaptations of the preferred embodiments will occur to those skilled in the art. However, it will be expressly understood that such modifications and adaptations are within the spirit and scope of the present invention as set forth in the following claims.

An alarm management system and method includes structure and function for receiving one or more process parameter signals representative of one or more process parameters. Each of the received process parameters is then compared with an associated alarm point. An alarm status signal is generated on the basis of the comparison. An annunciation command signal is transmitted on the basis of the alarm status signal. And, a sound is then generated on the basis of the annunciation command signal.

CROSS-REFERENCE TO RELATED APPLICATIONS This Application is related to U.S. patent applications Ser. No. 617,246, entitled IMPROVED RECIRCULATING DOCUMENT FEEDER, filed in the name of Russel et al; Ser. No. 617,337, entitled IMPROVED RECIRCULATING DOCUMENT FEEDER HAVING A CROSS-TRACK REGISTRATION MECHANISM, filed in the name of Rapkin et al; Ser. No. 617,249, entitled IMPROVED RECIRCULATING DOCUMENT FEEDER WITH STACK WEIGHT DETERMINED PRESSURIZED AIR/VACUUM LEVELS, filed in the name of Russel; Ser. No. 617,247, entitled IMPROVED RECIRCULATING DOCUMENT FEEDER WITH CONTROL OF DOCUMENT SHEET TRANSPORT, filed in the name of Russel et al; Ser. No. 617,336, entitled SEPARATION MEMBER FOR AN IMPROVED RECIRCULATING DOCUMENT FEEDER, filed in the name of Lawniczak; and Ser. No. 617,248, entitled MECHANISM FOR FACILITATING DOCUMENT SHEET SETTLING IN AN IMPROVED RECIRCULATING DOCUMENT FEEDER, filed in the name of Bergeron et al. All of these applications have been allowed. BACKGROUND OF THE INVENTION This invention relates in general to recirculating document feeders for use with electrostatographic reproduction apparatus, and more particularly to a recirculating document feeder having improved document sheet handling reliability due to a self-adjusting relation between the feeder and the reproduction apparatus. In order to increase the productivity and ease of use of electrostatographic reproduction apparatus, it has been common practice to provide such apparatus with automatic document set handlers Early automatic document set handlers accepted a document set stack and removed individual document sheets from the stack one at a time (see U.S. Pat. No. 3,747,918, issued Jul. 24, 1973, in the name of Margulis et al). The removed document sheet was delivered to an exposure station of the reproduction apparatus where the desired number of reproductions of such document sheet were made. Thereafter, the document sheet was returned to the stack and the next document sheet was delivered to the exposure station. Such sequence of document sheet feeding and reproduction necessitated the use of an auxiliary sorter device in conjunction with the reproduction apparatus to provide collated reproduction sets corresponding to the document set. The use of a sorter device added to both the complexity and expense of the reproduction operation. More recently, automatic document handlers typically referred to as recirculating document feeders have been developed. Recirculating document feeders, such as shown for example in U.S. Pat. No. 4,169,674 (issued Oct. 2, 1979, in the name of Russel) deliver document sheets seriatim to the reproduction apparatus exposure station and return the sheets to the document stack in order. At the exposure station, only one reproduction of each respective document sheet is made on one circulation. The desired number of reproductions is made by recirculating the document sheets from the stack to the exposure station and then back to the stack a corresponding number of times. By such reproduction sequence, the reproduction set of the document set is received at an output hopper in collated order. Thus no subsequent operational steps on the reproduction set are required. While recirculating document feeders have proven very popular in that they enhance productivity and increase ease of use of the reproduction apparatus, they require complex construction to reliably recirculate the document sheets and effectively handle the document sheets in a manner to prevent damage thereto. Further, the relationship between the recirculating document feeder and the reproduction apparatus has to be accurately set up and constantly maintained to remain in adjustment. This is necessary to assure proper feeding operation of the document sheets through the interface between the recirculating document feeder and the reproduction apparatus. It is typically required that such set up and adjustment maintenance be accomplished by a trained service technician or a technically skilled operator. This adds considerably to the overall cost of maintaining the apparatus in proper working order. SUMMARY OF THE INVENTION This invention is directed to an improved recirculating document feeder for presenting sheets from a document sheet stack individually to a station of the reproduction apparatus for reproducing of information contained on such sheets, the recirculating document feeder having a self-adjusting relationship with the reproduction apparatus. The improved recirculating document feeder comprises a housing containing a support for a document sheet stack. A feed path extends away from and then back to the document stack support, for directing sheets from the support into association with the reproducing station and then back to the stack. Document sheets are selectively fed from the stack seriatim about the feed path. The feed for the document sheets includes a transport assembly overlying at least a portion of the reproduction apparatus station. The transport assembly is mounted for movement relative to the housing, and engageable by a spacer associated with the reproduction apparatus station for self-adjustment of the transport assembly in the mount to locate the transport assembly a predetermined distance from the reproduction apparatus station irrespective of the position of the housing relative to said reproduction apparatus station. The invention, and its objects and advantages, will become more apparent in the detailed description of the preferred embodiment presented below. BRIEF DESCRIPTION OF THE DRAWINGS In the detailed description of the preferred embodiment of the invention presented below, reference is made to the accompanying drawings, in which: FIG. 1 is a general view, in perspective, of a typical reproduction apparatus with the improved recirculating document feeder according to this invention in operative association therewith; FIG. 2 is a front elevational view, in cross-section and on an enlarged scale, of the improved recirculating document feeder according to this invention; FIG. 3 is a top plan view of a portion of the improved recirculating document feeder, with portions removed to facilitate viewing, particularly showing the document sheet stack support tray, side guide adjustment mechanism, and set count finger assembly; FIG. 4 is a top plan view of a portion of the improved recirculating document feeder similar to FIG. 3, with portions removed to facilitate viewing, particularly showing the document sheet stack support tray and feed belts; FIG. 5 is a side elevational view, in cross-section, of the portion of the recirculating document feeder shown in FIG. 4, taken along lines 5--5 of FIG. 4; FIG. 6 is a view, in perspective, of the set count separator assembly of the recirculating document feeder according to this invention; FIG. 6a is a top plan view of the set count separator assembly of FIG. 6 showing the remote position of the assembly finger in phantom; FIG. 7 is a side elevational view of a portion of the improved recirculating document feeder, with portions removed to facilitate viewing, particularly showing the cross-track adjustment and registration mechanism; FIG. 8 is front elevational view of a portion of the improved recirculating document feeder, with portions removed to facilitate viewing, particularly showing the individual document sheet positioner therefor; FIG. 9 is a graphical representation depicting the relationship between the number of document sheets in a document sheet stack and the pressure supplied to the air jet assembly; and FIG. 10 is a graphical representation depicting the relationship between the number of document sheets in a document sheet stack (for a particular sheet weight) and sensor signal. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the accompanying drawings, FIG. 1 shows a typical reproduction apparatus 10 having the improved recirculating document feeder according to this invention, designated generally by the numeral 12, associated therewith. The reproduction apparatus 10 may be for example an electrostatographic copier, a thermal or electronic printer, or a photographic printer. The requirement common for any selected typical reproduction apparatus is that it includes a reproducing station where a document sheet is received, and information contained on the document sheet is extracted for reproduction by the apparatus. An example of such a reproducing station is a transparent platen where a document sheet placed thereon is exposed by a light source to obtain a reflected light image of the contained information. Of course, it is suitable for this invention to optically or electronically scan the document sheet in any well known manner to obtain the information for reproduction. Further, the reproduction apparatus 10 includes an electronically based control system, or the like, such as a microprocessor based controller, which communicates with the recirculating document feeder 12 to operate the feeder in coordinated synchronism with the reproduction apparatus. As best seen in FIGS. 2-8, the improved recirculating document feeder 12 includes a housing 16 attached to the reproduction apparatus 10 for pivotable movement about an axis A (see FIG. 1) to a position for locating the feeder in operative association with the reproducing station 14, or a position remote from the station to provide ready access thereto. A document sheet stack receiving hopper 18 having a tray formed by a stack supporting surface 18a is located within the housing 16. When the housing is operatively associated with the reproducing station 14, the hopper supporting surface 18a is positioned at an angle to the horizontal. Accordingly, a document sheet stack (designated generally by the letter S) placed in the hopper 18 on the surface 18a is urged by gravity such that the individual sheets in the stack are respectively aligned along one edge against a locating wall 20 disposed transversely relative to the document sheet travel path to be described hereinbelow. Side guides 22 (see FIGS. 3, 4) are adjustably positioned to engage marginal edges of the document sheet stack adjacent to the sheet edge engaging the wall 20 to properly locate the sheet stack in the direction transverse to the sheet travel path. Adjustment of the side guides is accomplished, for example, by a manually operated rack-and-pinion system 22a as shown in FIG. 3. A mechanism 22b, such as an adjustable potentiometer connected by a gear to the system 22a for example, provides a signal to the operating computer of the reproduction apparatus 10 to indicate the setting (document sheet size) of the side guides 22. The area immediately above the hopper 18 is unobstructed so that the operator can readily place a document sheet stack S in the hopper and always have a clear view of the document sheets in the stack in the hopper. The document sheet stack is loaded in the hopper 18 in its natural (page sequential) order with the first page of information facing upwardly. To facilitate feed (removal) of document sheets from the hopper 18 into the document sheet feed path, the stack supporting surface 18a of the hopper has a depressed portion 18b located adjacent to the side of the hopper opposite the wall 20. A document sheet removal device 24 is located in juxtaposition with the depressed portion 18b of the stack supporting surface 18a of the hopper 18. As best seen in FIGS. 4 and 5, the document sheet removal device 24 includes a plurality of belts 26. The belts 26, which are selectively driven about a closed loop path, are entrained around a vacuum plenum 28 connected to a vacuum blower V (see FIG. 2) and have a run at a level substantially coincident with the depressed portion 18b. The plenum 28 has a series of ports 28' in the upper surface thereof, such ports communicating with apertures 26' in the belts 26. Vacuum in the plenum draws the bottommost document sheet in the stack S on the supporting surface 18a into the depressed portion 18b to effect attachment of such sheet to the belts 26 (see FIG. 5). Movement of the belts 26 about their path will then cause such bottommost sheet to be removed from the stack. The ease with which a document sheet can be removed from the bottom of a document sheet stack is dependent, at least in part, upon the sheet stiffness and weight, the overall weight of the document sheet stack, and the frictional force relationship between the bottommost sheet and the sheet immediately thereabove, the bottommost sheet and the supporting surface 18a of the hopper 18, and the bottommost sheet and the belts 26. In order to assure reliable document sheet removal, pressurized air is directed from an air pump P through an air jet assembly 30 toward the edge of the stack opposite the stack edge engaging wall 20 (i.e., the lead edge of the stack in the direction of sheet travel). The orientation of nozzles 30' of the air jet assembly 30 causes positive pressure air flow to be introduced between individual sheets of the document sheet stack S in the hopper 18. Such air flow levitates and separates the document sheets of the sheet stack. The force necessary to remove the bottom most sheet from the stack is thus reduced and misfeeds or multiple sheet feeds are substantially prevented. The introduction of positive pressure air flow by the air jet assembly 30 reduces the frictional force between the bottommost sheet and the sheet immediately above it. However, such air flow also increases the frictional force between the bottommost sheet and the hopper supporting surface 18a. Accordingly, the coefficient of friction properties of the feed belts 26 in contact with the bottommost sheet, the coefficient of friction between bottommost sheet and the supporting surface 18a, and the areas and surface roughnesses of these interacting elements must be taken into account to establish a desired level of vacuum necessary for the feed belts to remove only the bottommost sheet from the hopper 18a for delivery into a downstream travel path. The graphical representation of FIG. 9 shows the air jet assembly operating window for the recirculating document feeder 12 according to this invention, which extends from one document sheet to well over 100 sheets. Through the range of the number of document sheets in the document sheet stack in the recirculating document feeder (which determines the weight of the document sheet stack against the frictional surfaces thereof), it has been found necessary to either constantly vary the amount of vacuum and positive pressure air flow (line designated by the letter X in FIG. 9) or to vary those parameters in discrete steps (line designated by the letter Y in FIG. 9) such that the vacuum and pressurized air flow levels always define an operating point within the boundaries of the operating window. Operation at or near the boundary may result in lowered document sheet feeding reliability. This is due to the fact that too high an air flow may cause the document sheet stack to become disheveled, and insufficient air flow may enable the vacuum to effect multi-sheet feeds. When the air flow is kept within the defined operating window, the operation of the recirculating document feeder 12 has been reliable with document sheets in the range of thin papers (e.g., 13 lb. bond) up to and including heavy index and cover grades (e.g., 110 lb. index stock and 80 lb. cover stock). In order to establish the height of the document sheet stack, a set count assembly 32 (see FIGS. 3 and 6) is provided. The set count assembly 32 is located adjacent to wall 20 at the trailing edge of the document sheet stack S, and includes an elongated separator member in the form of a movable finger 32a. The finger 32a, extending through a slot 20a in the wall so as to overlie the trailing edge of the stack in the hopper 18, is supported on interconnected pivot rods R 1 , R 2 for pivotal movement about the two mutually perpendicular longitudinal axes of such rods. The rod R 1 permits the finger 32a to pivot such that the finger can freely follow the level of the initial topmost document sheet in the stack S supported on the stack supporting surface 18a of the hopper 18. On the other hand, rod R 2 is coupled to a rotary solenoid RS which upon actuation of the solenoid pivots the finger 32a to and from a remote position (phantom line position of FIG. 6 a). The end portion of the finger 32a, opposite to the end portion engaging the initial topmost document sheet in the stack S, engages a cam member C. The cam member C has a profile which, upon pivot movement of the finger 32a about the longitudinal axis of rod R 2 by the rotary solenoid RS after the initial topmost sheet is fed from the hopper 18, causes the finger to move to its remote position, to be raised to a level above the maximum stack height accommodated in the hopper, and returned to its initial position (solid line position of FIG. 6a) to once again engage the initial topmost sheet returned to the stack S. In operation, at the beginning of a reproduction cycle, the set count finger 32a is located so as to contact the initial topmost sheet of the document sheet stack. A sensor 34 detects the position (height above the stack supporting surface 18a) of the set count finger 32a resting on the top of the document sheet stack S, and thus enables the thickness of the stack (which is also a simple measure of the number of sheets in the stack) to be determined. The sensor 34 provides a signal which communicates with the operating computer of the reproduction apparatus 10 to enable the computer to set the speed of the vacuum blower V and/or adjust various valves (not shown) to proportion the pressurized air and vacuum levels to levels that have been predetermined to provide satisfactory operation for the detected number of document sheets in the stack. Alternatively, several switches may be used to accomplish measurement of the document sheet stack height, detecting for example that the stack contains less than 10, between 10 and 50, or more than 50 sheets. The set count assembly 32 also includes a sensor 36 which detects when the last document sheet of the stack S (the one which initially was topmost at the start of the reproduction cycle) has been fed from the hopper 18. An opening 18c defined in the sheet supporting surface 18a of the hopper is located to enable the set count finger 32a to drop through the supporting surface to a position below the supporting surface when the last document sheet has been fed. At such position, the sensor 36 "sees" the set count finger and provides a signal which communicates with the reproduction apparatus computer to indicate that a reproduction of the entire document sheet stack has been completed. The computer can then precisely determine the number of document sheets in the stack, since it has been counting the number of sheets fed as the reproduction cycle has progressed. At the completion of reproduction of the first document sheet stack set, the computer can readjust the pressurized air and vacuum levels to levels corresponding to the optimum operating levels for the particular number of document sheets in that document sheet stack. Further, a sensor 38 (see FIG. 3) is mounted in association with the side guides 22 to detect the location thereof. The sensor 38 provides a signal which communicates with the reproduction apparatus computer to indicate the setting for which the side guides 22 have been adjusted (i.e., for the size of the document sheets that the side guides have been adjusted to accommodate). Input of the size of the document sheets enables the computer to calculate or otherwise determine the total weight of the document sheets in the hopper 18. Based upon the determined total weight of the document sheet stack, the computer can then provide for an additional adjustment of the pressurized air and vacuum levels to produce optimum performance and maximum reliability of the recirculating document feeder 12. If the pressurized air flow is too high, it can cause excess fluffing of the document sheet stack. Excess fluffing of the sheet stack creates a condition where, at the completion of reproduction of a document sheet stack set, the set count finger 32a can be improperly returned to other than the top of the sheet stack. To avoid such condition, the reproduction apparatus computer is programmed to pause after the end of a reproduction cycle for the document sheet stack set (as determined by sensor 36 detecting the set count finger 32a), and turn off the air pressure momentarily. This enables the stack to settle in the hopper 18 and the set count finger 32a to return reliably to rest on the top sheet of the settled stack. Then the computer, knowing exactly the number of document sheets, can readjust the pressurized air and vacuum level settings. Since heavy weight document sheets are ordinarily thicker than light weight document sheets, determining the number of sheets in the document sheet stack is not a perfect measure of the stack weight. However, by comparing the document sheet stack height as determined by the stack height sensors with the actual count of the number of document sheets, the reproduction apparatus computer can calculate the thickness of each sheet. Suppose, for example, that there is only one stack height sensor (e.g., sensor 34) set to detect if there are more than ten sheets of 20 lb. bond paper in the hopper 18. When the reproduction cycle starts, the set count finger 32a is placed on top of the stack. If the sensor detects that there are more than ten sheets of paper, the computer does not know how many more sheets are in the stack, nor does it know what the thickness (and thus the weight) of each sheet is, nor can it calculate the total weight of the stack. In this example, if the computer counts 25 sheets when it senses the end of reproduction of the first document sheet stack set, it still does not know the thickness of each sheet. The best the computer can do is adjust the pressurized air and vacuum levels to levels corresponding to the center of the operating window for 25 sheets with a weight equivalent to 20 lb. bond paper (most commonly used and nearest to average sheet weight). If, however, the sheets are actually 110 lb. index stock instead, they will weigh about twice as much as 25 sheets of 20 lb. bond paper. For optimum operation on 110 index stock, the pressurized air and vacuum level settings should be relatively increased to provide better levitation of the stack above the bottommost sheet and an increased driving force between the drive belts and the bottommost sheet to better pull the bottommost sheet out from underneath the weight of the stack above it. If, however, the stack height sensor 34 initially detects that there are fewer than ten sheets of 20 lb. bond paper, the computer can set the pressurized air and vacuum levels accordingly, but it still does not know exactly how many sheets there are in the stack, nor their weight. In order to provide for more accurate control of the pressurized air and vacuum level settings, the following method may be employed. Suppose, for example, that on start of the reproduction cycle, the sensor 34 detects that more than the equivalent of ten sheets of 20 lb bond paper are contained in the stack in the hopper 18. The reproduction apparatus computer, on receipt of the appropriate signal from the sensor 34, sets the initial pressurized air and vacuum levels. As the reproduction cycle continues, at some point the set count finger 32a will pass through the point at which it senses ten sheets of 20 lb. bond paper. From that point on, the computer tallies a second count of the number of sheets to the completion of reproduction of the document sheet stack set. If the computer counts approximately ten sheets, then it knows that the sheets are probably 20 lb. bond paper; if it counts approximately five sheets, then it can deduce that the sheets are a heavier grade, like 110 lb. index stock; and if it counts approximately twenty sheets, then it can deduce that the sheets are probably 13 lb. bond paper. Now the computer has enough information to determine the weight of the entire stack since it also knows the total number of sheets in the document stack and can multiply the total number of sheets by the deduced weight of each sheet. This additional information is sufficient to alter the pressurized air and vacuum level settings to approximate optimum level settings for the determined stack height and weight The setting of pressurized air and vacuum levels is most critical for sheet stacks of heavy weight papers. The described additional intelligence that the computer gains from deducing the individual sheet weight allows the earliest possible optimization of operating parameters for the recirculating document feeder 12 to be attained. On the other hand, for stacks with fewer than ten sheets, precise setting of the vacuum level is not as important. That is, with smaller stacks, excess gripping force between the feed belts 26 and the bottommost sheet is not a disadvantage unless the paper is porous enough so that the next bottommost sheet in the sheet stack is also attracted to the belts (which can result in a multiple sheet feed). Setting of the air pressure level for the air jet assembly 30, however, is more critical with only a few sheets since excess air pressure may cause the sheets to be lifted entirely out of the hopper 18. Accordingly, to improve the ability to optimally provide for pressurized air and vacuum level settings, it is desirable to provide at least two levels of pressurized air and vacuum level settings and two stack height sensors (e.g., 34 and 34 a) for determining the initial start-up operating parameters. For document sheet stacks containing less than the minimum number of sheets detectable by the stack height sensor (i.e., ten sheets in the above example), the computer still does not know whether the weight of the sheets is light, medium, or heavy. But, since the operating window is sufficiently wide, it has been found that reliability for recirculating sheets of smaller stacks is not appreciably degraded. The second stack height sensor 34a enables a finer determination of the height of the document sheet stack to be made; e.g., less than five sheets, between five and ten sheets, and more than ten document sheets. With such a sensor arrangement, the reproduction apparatus computer can tally the number of sheets required for actuating the different stack height sensors as the set count finger 32a passes through the range from the start of the reproduction cycle to the end of the cycle. If the computer starts out knowing, for example, that there are more than ten sheets, it can wait until the ten-sheet sensor is actuated, then tally the number of feed cycles necessary to detect the actuation of the five-sheet sensor. If the number of document sheet feeds is approximately five, then the document sheets are probably 20 lb. bond paper. If the tally is only two or three, then the sheets are probably 110 lb. index stock, and the pressurized air and vacuum level settings can be adjusted without having to wait until the end of a reproduction cycle for the document sheet stack set. The earlier the setting determination is made, the sooner the operating parameters can be optimized so as to enhance the reliability of document sheet separation and feeding. The concept of utilizing multiple stack height detection sensors can be carried to its ultimate extent by employing an analog stack height sensor rather than the discrete (digital) sensors (34, 34a) described above. When the set count finger of the set count assembly comes to rest on the top of the document stack, the analog sensor provides an analog voltage signal (directly corresponding to stack height) to the reproduction apparatus computer. Accordingly, for each position of the set count finger, the computer can calculate the number of document sheets in the stack. The graph of FIG. 10 shows a straight-line correspondence between the document sheet stack (set count finger) height and number of document sheets for various weights of paper (i.e., line E corresponds to 110 lb. index stock, line F corresponds to 20 lb. bond paper, and line G corresponds to 13 lb. bond paper). As the reproduction cycle begins, the pressurized air and vacuum level settings are set at a default (compromise) condition since the computer does not know whether the document sheets in the stack are heavy or light in weight. As the reproduction cycle continues, however, the computer can count the number of feed cycles and compare the actual count of document sheets fed with the calculated number of document sheets based on the instantaneous height of the set count finger. From this comparison, the computer can match the slope of the actual straight line correspondence between the set count finger height and the number of sheets with one of the theoretical paper weight lines (lines E, F, or G) to determine the individual sheet weight. According to such determination, the computer can accurately predict the number of sheets in the document sheet stack and the weight of the stack within only a few sheets, and readjust the pressurized air and vacuum level to optimum settings. Another way of looking at the concept of utilizing the analog stack height sensor 34' to determine stack weight can also be seen in FIG. 10. By the two horizontal lines drawn through 5 volts and 4.9 volts in the graph, it can be seen that six sheets of 13 lb. bond paper (line G), four sheets of 20 lb. bond paper (line F), or two sheets of 110 lb. index stock (line E) each cause the analog stack height sensor to transmit the same amount of voltage change to the computer. Regardless of the number of sheets, if the computer calculates that the analog sensor voltage is changing at the rate of so many sheets per volt, multiplying the value of sheets per volt times the initial analog sensor voltage determines the number of initial sheets, or the total number of sheets in the stack and thus allows the calculation of the total weight of the stack. This can be done within just a few feed cycles at the beginning of reproduction of the document sheet stack, then updated at mid-stack or at the end of the reproduction cycle for the stack. Referring again to FIG. 2, as a document sheet is fed from the hopper 18, it passes beyond air jet assembly 30 where its lead edge is captured by the transport belt 50 entrained in part about wheel 52 (the transport belt and wheel arrangement may include multiple belts and corresponding wheels positioned in spaced relation along the longitudinal axis L 1 of wheel 52). The belt 50/wheel 52 arrangement defines a sheet travel path between the hopper 18 and the platen 14 of the reproduction station of apparatus 10. As the lead edge of the sheet is captured, it passes across a lead edge fed sensor 54. This tells the reproduction apparatus computer that the sheet has been successfully fed and that the vacuum applied to the plenum 28 (and thus feed belts 26) can be turned off. The drive for the feed belts 26 continues so that the belts do not present a frictional drag on the sheet; and the drive for the feed belts 26 is turned off after the trailing edge of the document sheet has passed the area of such belts. At that time, vacuum is re-established in the plenum 28 so as to cause the next document sheet (now the new bottommost document sheet of the stack) to adhere to the belts 26 to ready such sheet for feeding in the proper timed sequence. However, such sheet is not yet drawn into the stream of the sheet travel path because the belts 26 are stationary. Meanwhile, the first document sheet is fed by transport belt 50 and continues its travel around wheel 52. In the case of simplex copying, since only the front side of the respective document sheets are to be copied, the document sheet is directed onto the platen 14 past platen entrance sensor 56. The document sheet is driven by transport belt 50 until the lead edge is adjacent apertured platen drive belts 60. The platen drive belts 60 are entrained about rollers 62, and are selectively driven in a closed loop path in the direction of the associated arrow with the lower run of the belts in juxtaposition with the platen 14. A multi-chamber vacuum plenum 64 is located within the closed loop path and has a ported lower surface so as to operatively communicate with the lower run of the apertured platen drive belts 60. Accordingly, with vacuum applied to both chambers 64a and 64b of the plenum 64, the belts 60 effectively grasp the document sheet and transport it across the platen 14. At an intermediate point in the travel of the document sheet across the platen, the speed of the platen drive belts 60 is slowed so that as the sheet is brought into contact with a lead edge registration gate 66, the sheet does not strike the gate with such force as to damage its leading edge. Additionally, vacuum to the first camber 64a of the multi-chamber plenum 64 is turned off, leaving only the vacuum applied to the second chamber 64b and the portion of the belts 60 nearest the lead edge of the sheet at registration gate 66. After the lead edge of the document sheet has been registered against the gate 66, the document sheet is registered in a cross-track direction (transverse to the sheet travel path) by a cross-track registration mechanism 70. As best shown in FIG. 7, the mechanism 70 includes a first solenoid 72 which when actuated rotates a pivotable crank arm 74 to cause a foot 76 to lower against the platen 14. This establishes a registration edge for the front marginal edge of the document sheet (the edge nearest the operator). The registration edge defines a position for the document sheet where the image of information contained on the document sheet can be properly and consistently reproduced on an aligned receiver sheet in the reproduction apparatus 10. A second solenoid 78 of the cross-track registration mechanism 70 is actuated after the foot 76 engages the platen 14. The second solenoid 78 rotates a pivotable rocker arm 80 to bring a rotating wheel 82 down onto the document sheet. The rotating wheel 82 moves the document sheet laterally across the platen 14 (transverse to the direction of travel of the document sheet about the closed loop path from the hopper 18 to the platen 14 and back to the hopper) until the front marginal edge of sheet is registered against the foot 76. The solenoid 78 thereafter effects raising of the rotating wheel 82 so as to not disturb the registered sheet. After the document sheet has been properly registered at the gate 66 and against the foot 76, the reproduction apparatus 10 exposes the sheet in any well known manner to obtain an image of the information contained on the sheet. Subsequent to exposure of the document sheet, the lead edge registration gate 66 is lowered to a remote position out of the document sheet travel path, and platen drive belts 60 are allowed to transport the sheet off the platen 14. The document sheet is then directed into engagement with transport belt 90 and wheel 92 which capture the sheet and carry the sheet around the wheel 92 (in a manner similar to the transport effected by the transport belt 50 and wheel 52) defining a travel path between the platen 14 and the hopper 18. The normal document sheet travel path from hopper 18 via belt 50/wheel 52 to platen 14 assures that the top (information bearing) face of the document sheet will be placed face down on the platen 14. Thereafter, return of the document sheet from its face down orientation on the platen 14 via belt 90/wheel 92 to the hopper 18 will always return the document with a face up orientation in the hopper. The return of document sheets to the hopper 18, for proper restacking on the stack S supported on the surface 18a, is assisted by a driven nip roller assembly 140. The nip roller assembly, located downstream of the belt 90/wheel 92 (in the direction of document sheet travel), maintains control of respective document sheets until they are well into the area over the stack S. Further, at least one flexible strip of material 142 (commonly referred to as a dangler) intercepts the travel path of the returning document sheets exiting from the nip roller assembly 140. The strip 142 urges the returning document sheets downwardly toward the stack. However, it takes some time for a document sheet to settle on the stack in the hopper 18. With the rapid operational characteristics for the recirculating document feeder 12 according to this invention, it is necessary to assure rapid settling to prevent misfunction of the feeder operation, such as for example the return of the set count assembly finger 32a prior to settling of the initial topmost document sheet on the stack. Accordingly, an air jet assembly 144 is provided. The air jet assembly directs pressurized air from above the document sheet travel path toward the stack S downstream (in the direction of document sheet travel) of the flexible strip 142. The positive air pressure acts on the returning document sheets to cause the respective sheets to be expeditiously restacked with the least amount of resettling time The recirculating document feeder 12 according to this invention is constructed in a particularly described manner to selectively turn document sheets over whereby information contained on both sides thereof can be imaged in proper sequence by the reproduction apparatus 10. Accordingly, the apparatus 10 can accomplish duplex copying or simplex copying from duplex document sheet stacks, while maintaining the document sheets in face up order in the hopper of the recirculating document feeder 12 to enable an operator to always be able to see such face. With a document sheet stack of duplex documents (i.e., documents which contain information on both the front and back sides thereof), in order for the finished reproduction sets to be in proper sequential order, alternating reproduction cycles image the back side of each document sheet in the stack and then the front side of each document sheet. The respective cycles for imaging of the front sides of the document sheets is carried out in the manner described above. On the respective alternate cycles, when it is desired to image the back sides of the document sheets, a document sheet is fed from the hopper 18 by the document sheet removal device 24 described above, and progresses across the top of diverter 100 to be captured by belt 50 and wheel 52. As the trailing edge of the document sheet passes the sheet fed sensor 54, belt 50 and wheel 52 are stopped by a clutch/brake assembly (not shown). Diverter 100 is then rotated slightly counter clockwise to its phantom line position in FIG. 2, into intercepting relation with the document sheet travel path, and belt 50 and wheels 52 are driven to rotate in a reverse direction. Accordingly, the captured document sheet is transported in a reverse direction and directed by the diverter 100 into a secondary travel path P S1 . When in the secondary travel path P S1 , the document sheet is detected by the platen entrance sensor 56 as it is transported onto platen 14. The signal from the sensor 56 to the reproduction apparatus computer causes the sequence of platen transport events described above to be carried out in the manner described above. The transport of the document sheet through the secondary travel path P S1 effects an inversion of the document sheet so that the back side thereof is face down on the platen 14 for imaging of the information contained thereon. Meanwhile, as the trail edge of the document sheet passes the platen entrance sensor 56, diverter 100 is returned to its normal (solid line) position, the direction of drive for the belt 50 and wheel 52 are reversed (to their initial drive direction), and the drive belts 26 are readied to accept another document sheet feed command. After the back side of the document sheet has been imaged, registration gate 66 is lowered, platen drive belts 60 are actuated to drive the document sheet off the platen 14, and the document sheet is transported to the belt 90 and wheel 92 for capture thereby. However, if such document sheet were allowed to proceed in the travel path described above, the sheet would end up in hopper 18 with its front side (originally upwardly oriented face) oriented downwardly. This condition would cause confusion for the operator and would place the document sheets in an improper page sequential order. In order to overcome these problems and return the document sheet to the hopper 18 in its original first side face up orientation, return sensor 102 detects the lead edge of the document sheet and provides an appropriate signal for the reproduction apparatus computer. Such signal causes the diverter 104 to be rotated slightly counter-clockwise to its phantom line position in FIG. 2, into intercepting relation with the document sheet travel path, and the direction of drive for belt 90 and wheel 92 to be reversed through a clutch/brake (not shown). The document sheet is thus directed to proceed through a secondary travel path P S2 . As the trailing edge of the document sheet passes the platen exit sensor 106, the sensor detects the sheet and provides an appropriate control signal for the computer. In response to such control signal, the diverter 104 is returned to its normal (solid line) position where it is ready for directing travel of the next document sheet. Meanwhile, the document sheet proceeds along the secondary travel path P S2 back into hopper 18, and completion of the feed cycle for such sheet is determined by the return sensor 102 which detects the trailing edge of the sheet. This process is repeated for each document sheet in the stack, and for the number of times equal to the operator selected desired number of reproductions of the document stack. An important aspect of the recirculating document feeder 12 according to this invention is the use of an adaptive timing control of the various transport elements of the feeder as opposed to a strict fixed time sequencing of events. This has been found to be necessary since experience has shown that the physical characteristics of the document sheets varies not only from brand to brand, but from sheet to sheet, even within the same ream. It is natural, therefore, to expect that the passing of a sheet over mechanical devices that induce drag, frictional forces and other influences can present different timing effects on each sheet even if all document sheets of a stack are created from paper from within the same ream. Moreover, the individual document sheets of a stack may not all be the same kind, brand, weight or texture. With the high transport speeds necessary in modern reproduction apparatus including a device such as the recirculating document feeder 12, individual events occur during extremely short time intervals, for example on the order of a few milliseconds each. A fixed timing controller which follows a definitive program to turn on and off clutches, pressurized air and vacuum valves, solenoids, etc., can hardly be expected to present an optimum set of operating conditions for each individual sheet in a stack. In order to control the sequence of events and to maximize the reliability of the recirculating document feeder 12 and its individual elements, a more individualistic operational approach is utilized. The sensors that control the timing of individual events are best shown in FIG. 2. Sensor 54 detects that a document sheet has actually been fed from the hopper 18 sufficiently for the transport belt 50/wheel 52 to capture and control the transport of the sheet. Platen entrance sensor 56 detects that the document sheet has properly negotiated the turn about the wheel 52 and is progressing toward the platen 14. As the lead edge of the document sheet is detected by the platen entrance sensor 56, the reproduction apparatus computer effects establishment of the vacuum levels in the multi-chamber plenum 64 and sets the appropriate speed of the transport belts 60. As the trail edge of the document sheet is detected by the platen entrance sensor 56, the drive for the transport belts 60 is adjusted to start slowing down the belts to a second appropriate speed so as to prevent lead edge damage as the document sheet is registered at the gate 66. Platen exit sensor 106 detects that the document sheet has actually left the platen 14 and effects an increase in the velocity of the belts 60 to transport the sheet off the platen as quickly as possible. As the trail edge of the document sheet is detected by the platen exit sensor 106, a control signal to the computer indicates that the document sheet has been captured by the transport belt 90/wheel 92 sufficiently to be the sole transporting mechanism for the document sheet, and that the gate 66 can be returned to its travel path intercepting position in readiness for registration of the next document sheet. Return sensor 102 detects that the document sheet is returning to the hopper area as the lead edge of the sheet is detected, and that the sheet has completely left the transport belt 90/wheel 92 as the trailing edge of the sheet is detected by such sensor. In the mode of operation for handling duplex document sheets, all of the described events become more important when the action of the reversal clutch/brakes and travel path diverters are brought into play. Upon the detection of the trail edge of a document sheet by the fed sensor 54, such sensor provides a signal for the computer to indicate that the document sheet is clear of the diverter 100 and that it is safe to move such diverter to its phantom line position. When the document sheet travel is then reversed by actuation of a clutch/brake to reverse direction of the transport belt 50/wheel 52, the document sheet can enter properly into the secondary travel path P S1 . As the trail edge of the document sheet is detected by the platen entrance sensor 56, the diverter 100 can be allowed to return to its solid line position in preparation for directing the next document sheet. Likewise, as the trail edge of the document sheet is detected by the platen exit sensor 106, an appropriate signal to the computer indicates that it is safe to move the diverter 104 to its phantom line position so that the document sheet, on reversed travel, can enter into the respective secondary return travel path P S2 . The times of the document sheet transport events is monitored as each document sheet progresses around the travel path from hopper 18 to platen 14 and back to the hopper. Comparing the nominal estimated times for these events with the actual times enables the computer to decide, based on experience criteria, to allow the document sheet transportation cycle (and thus the reproduction cycle) to continue, or to stop the sheet transport entirely in order to prevent a jam condition from causing damage to the document sheet. Additionally, the individual sheet timing measurements can be used to alter the velocity of travel path transport belts, rollers and drives so as to correct the document sheet travel velocities in various portions of the travel path and bring them back to a nominal condition. This sort of adaptive timing will enable the recirculating document feeder 12 to accommodate for things like excessive friction buildup in drive shafts, bearings and the like, or for loss of sheet velocity because of slippage on frictional surfaces. Within reason, adjustments can be made in the velocities of drive shafts, as long as there is a limit to the amount of adjustment correction imposed. That is, a certain amount of speed correction is employed in conjunction with statistical data collection and analysis that points to diverse occurrences such as potential bearing seizures, friction surface changes and the like, which are communicated to service personnel to indicate that certain mechanical or electrical components are in need of replacement or other attention. As another aspect of the recirculating document feeder 12 according to this invention, such feeder is constructed to enable an operator to introduce a single sheet onto the platen without having to place it in the hopper 18. As shown in FIG. 8, a document sheet D is placed on a work surface 110 of the reproduction apparatus 10 adjacent to the feeder 12. The document sheet is manually urged into the feeder 12 until the sheet intercepts a document present sensor 122. This action signals the feeder to complete its present reproduction cycle, reverse the direction of transport belt 50/wheel 52, and to actuate solenoid 114 which pulls cam lever 116 so as to raise plate 118. Raising the plate 118 brings roller 120 into engagement with belt 50 to capture the document sheet D between roller and the belt, and transport the sheet forward (toward the left in FIG. 8) until it strikes gate 122. Since the document sheet is being constantly urged against the gate 122 by the belt 50, any skew in the document sheet is corrected by alignment of the sheet with the gate. At an appropriate time, solenoid 124 is actuated to raise gate 122, allowing the properly aligned document sheet to proceed onto the platen 14. The document sheet is transported across the platen 14 by belts 60 up to gate 66 where sheet alignment is corrected a second time if necessary. After the reproduction apparatus 10 has captured an image of information contained on the document sheet, gate 66 is lowered, diverter 104 is moved to its phantom line position, and the document sheet is transported off the platen 14 into a collection hopper 126 (shown in FIG. 1). Successive document sheets can be introduced into the recirculating document feeder 12 in a like manner. The recirculating document feeder 12 according to this invention can also be used in a manual mode. For manual mode use, the operator lifts the feeder about its pivot connection with the reproduction apparatus 10 and places a document on the platen 14. The feeder is then returned to its closed position if the document has no substantial thickness (i.e., a sheet of paper), or remains in the partially raised position in the instance where the document is a book or solid object while the reproduction apparatus makes a reproduction. Moreover in the manual mode for the recirculating document feeder 12, the reproduction apparatus 10 can be used to make reproductions of continuous computer forms (fan-fold sheets). A tractor drive mechanism (not shown) is attached to the reproduction apparatus to pull the continuous computer forms across the platen 14 under the recirculating document feeder in its closed position without having to thread the forms through any part of the feeder. Further, the recirculating document feeder can be raised or closed without disturbing the continuous computer forms path. Another aspect of the recirculating document feeder according to this invention is to provide a constant gap between the base plate 130 and the platen 14. Since document sheets must pass through this gap in their travel across the platen, this spacing is a critical parameter. That is, if the gap is too large, the document sheet may not properly register at the gate 66 and foot 76 and may be held out of the depth of focus for the imaging system of the reproduction apparatus 10; on the other hand, if the gap is too small, the document sheet may jam between the base plate and the platen. The base plate 130, supported in the housing 16 of the recirculating document feeder 12, carries the platen transport belts 60 (and associated multi-chamber vacuum plenum 64) and the cross-track registration assembly 70. The support for the base plate 130 includes springs 132 urging the base plate in a direction toward the platen 14 when the recirculating document feeder 12 is in operative relation with the reproduction apparatus 10. Accordingly, the base plate 130 will "float" relative to the remainder of the recirculating document feeder when the feeder is lifted off the platen, but will come to rest against fixed spacer pads 134 when the feeder is in operative association with the reproduction apparatus. The spacer pads 134 accurately determine the spacing between the base plate and the surface of the platen. With this described spacer pad arrangement, there are no adjustments necessary to guarantee the spacing between the base plate and the platen during operative association of the recirculating document feeder with the reproduction apparatus. In addition, since the vacuum to the belts 60 is effective in this constant predetermined gap, air flow characteristics passing through this space are guaranteed to be more stable and determinant from one recirculating document feeder to another since the flow is effective in a fixed space rather than a variable space that would result from differing adjustments. The invention has been described in detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.

An improved recirculating document feeder for presenting sheets from a document sheet stack individually to a station of the reproduction apparatus for reproducing of information contained on such sheets. The improved recirculating document feeder comprises a housing containing a support for a document sheet stack. A feed path extends away from and then back to the document stack support, for directing sheets from the support into association with the reproducing station and then back to the stack. Document sheets are selectively fed from the stack seriatim about the feed path. The feed for the document sheets includes a transport assembly overlying at least a portion of the reproduction apparatus station. The transport assembly is mounted for movement relative to the housing, and engageable by a spacer associated with the reproduction apparatus station for self-adjustment of the transport assembly in the mount to locate the transport assembly a predetermined distance from the reproduction apparatus station irrespective of the position of the housing relative to said reproduction apparatus station.

FIELD OF THE INVENTION This invention relates to confection holding devices, and more particularly relates to a symmetrically shaped holding device which is suitable for automatic mechanical insertion within a conical container. DESCRIPTION OF THE PRIOR ART It has long been known to utilize rigid holding sticks of plastic or wood to support confections, such as ice cream or the like. In addition, it has become popular to provide a plastic statuette on one end of the confection holding device to hold the confection and to serve as a prize for the consumer. Such a confection holding device including a plastic statuette, is described in U.S. Pat. No. 3,085,883, issued Apr. 16, 1963. However, such prior confection holding devices which include statuettes have been time consuming and expensive to insert into confection containers, inasmuch as care must be taken to orient the statuettes within the containers in the desired position. The corrrct orientation of the statuette within a conical container has thus heretofore been achievable only through time consuming and laborious manual insertion. Moreover, such pior confection holding devices which include statuettes present a risk of injury to the mouth of the consumer, due to the irregular and sharp shapes of the statuettes which are hidden by the confection. A need has thus arisen for a confection holding device which automatically orients itself in a confection container when mechanically inserted, thereby resulting in a substantial savings in time and money over devices in the prior art. In addition, there is a need for a confection holding device which substantially reduces a consumer's risk of harm from mouth injuries caused by the shape of the holding device. SUMMARY OF THE INVENTION The present invention provides a symmetrical confection holding device offering a savings in time and money in its capability of automatically orienting itself upon mechanical insertion within a conical container, and a holding device which reduces the consumer's risk of harm from such an object. In accordance with the present invention, a symmetrical holding device for a confection is positioned within an open ended conical container. The holding device has a central body portion with an annular surface of smaller circumference than that of the open end of the container, thereby enabling the annular surface of a central body to engage the inner surface of the container when positioned within it. The positioning of the holding device within the conical container thus divides it into first and second chambers, separated by the central body of the holding device. In accordance with another aspect of the invention, the holding device has first and second elongate members extending perpendicularly from opposite sides of the annular surface of the central body. The elongate members are symmetrical about the annular surface of the central body. The first elongate member extends into the first upper chamber and the second elongate member extends into the second lower chamber, when the holding device is positioned within the conical container. The central body and first elongate member supports confection placed within the first chamber. The second elongate member, segregated from the confection by the seal of the central body, serves as a holding devive for supporting the confection when the conical container is removed. BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the present invention and further objects and advantages thereof, reference is now made to the following description taken in conjunction with the following drawings: FIG. 1 is a perspective view of the preferred embodiment of the invention; FIG. 2 illustrates a system for mechanically inserting the invention into an open ended conical confection container; FIG. 3 is a side view of the preferred embodiment of the invention in an empty open ended conical confection container; FIG. 4 is a side phantom view of the preferred embodiment of the invention positioned within an open ended conical container filled with a confection; FIG. 5 is a perspective view of an alternate embodiment of the invention; and FIG. 6 is a perspective view of still another embodiment of the invention. DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows a perspective view of the preferred embodiment of the present holding device, generally identified by the numeral 10. Elongate members 12 and 14 integrally extend from opposite sides of a central body portion 16, which is shaped as a circular disk. Elongate members 12 and 14 are symmetrical about and perpendicular to the annular surface 18 of central body portion 16. Elongate member 12 has a circular cross section throughout its length and has an upper relatively small diameter end 22 and a periphery which curves outwardly to a relatively large diameter lower portion integrally attached to central body 16. Elongate member 12 is connected by beveled annular surface 24 to its end 22. Elongate member 14 has a circular cross section throughout its length and has a relatively small diameter end 23 and a periphery which curves outwardly to a relatively large portion integrally attached to central body portion 16. Elongate member 14 is connected to end 23 by a beveled annular surface 25. An important advantage of the confection is the substantial reduction in risk of injury to the mouth of the consumer. The periphery of elongate members 12 and 14 curving outwardly from their respective ends 22 and 23 conform more readily to the mouth than an irregularly and unknown shaped statuette. All the confection may be removed from the periphery of elongate member 12 without encountering any irregular shape or sharp object which might harm the consumer. FIG. 2 illustrates a system for automatically mechanically inserting the invention 10 in an open ended conical container 30. The system consists of a mechanical apparatus, generally referred to by numeral 80, for storing and discharging one symmetrical holding device 10 into an open ended conical container 30 moving beneath the mechanical apparatus 80 on conveyor 100 powered by electrical motor 102. Electrical motor 102 is synchronized with discharge release motor 98 on mechanical apparatus 80 by a control unit 104. The mechanical storage/discharge unit 80 has an elevated hopper 82 for storing a plurality of symmetrical holding devices 10 in random orientations. Pressure plate 84 is positioned within elevated hopper 82 above a circular opening 88 in hopper 82. Agitator 86 is a rigid member attached to pressure plate 84 and rotates directly above opening 88. Agitator 86 is powered by a small electrical motor 87 positioned within pressure plate 84 and moves holding devices above circular opening 88. Electrical motor 87 is connected to an outside power source through the walls of hopper 82. Agitator 86 provides a continuous flow of holding devices 10 from hopper 82 through opening 88. Hopper opening 88 feeds holding devices 10 into the discharge unit 90. Holding devices 10 pass through the circular opening 88 into cylindrical tube 92 which has a circumference larger than that of annular surface 18 of central body portion 16. Symmetrical holding device 10 passes by gravity from opening 88 to discharge release mechanism 94 with elongate members 12 and 14 in the vertical plane within cylindrical tube 92. Discharge release mechanism 94 consists of an eccentric wheel energized by electric motor 98 synchronized through control 104 to conveyor motor 102. The discharge release mechanism 94 operates to maintain those holding devices 10 within cylindrical tube 92 while releasing a single holding device 10 to spring operated trap door 96 for release into open end of conical container 30 positioned beneath trap door 96 by conveyor 100. Symmetrical holding device 10 automatically aligns itself upon dropping within conical container 30. This container 30 moves by conveyor 100 for the filling of the upper part of the conical container 30, defined by central body portion 16, with a confection such as ice cream or the like. The annular surface 18 of central body portions 16 snugly engages the inner walls of conical container 30 to provide a seal for the confection. It will of course be understood that the holding devices may be dropped into the containers 30 by any suitable conventional dispersing method. FIG. 3 is a side view of a symmetrical holding device 10 positioned within an empty open ended conical container 30. The circumference of the annular surface 18 of central body portion 16 is less than the circumference of the annular base 32 of conical container 30, thereby allowing holding device 10 to be positioned within container 30. Holding device 10 engages the inner surface of conical container 30 where the circumference of annular surface 18 is equal to the inner circumference of the conical container 30. Central body portion 18 divides conical container 30 into first upper chamber 38 and second lower chamber 39. The upper chamber 38 is defined by the open end of conical container 30, the inner walls of conical container 30 up to the point where central body portion 16 engages the conical container 30, and the upper portion of central body portion 16 itself. The lower chamber 39 is defined by the opposite portion of central body portion 16 and the inner surface of conical container 30 extending from where central body portion 16 engages the surface of conical container 30 to the apex portion 34 of the conical container 30. Elongate member 12 extends into upper chamber 38 and elongate member 14 extends into lower chamber 39. The beveled annular surface 25 engages the inner surface of conical container 30 at a point where the circumference of the beveled annular surface 25 is equal to the circumference of the annular surface of conical container 30. The engagement of symmetrical holding device 10 with the inner surface of conical container 30 by the central body portion 16 and beveled annular surface 25 automatically maintains the annular surface 18 of central body portion 16 perpendicular to the central axis 31 of conical container 30. The snug engagement of annular surface 18 with the inner walls of conical container 30 also serves to act as a seal to prevent the leakage of confection from the bottom of upper chamber 38 into lower chamber 39 and from the bottom of container 30 itself. FIG. 4 is a side phantom view of symmetrical holding device 10 positioned within a conical container 30 filled with confection 50, such as ice cream, flavored ice, or the like. Confection 50 seals upper chamber 38 and an area above the open end of conical container 30. Confection 50 is supported by the inner walls of conical container 30, elongate member 12 extending in the upper chamber 38, and central body portion 16. Elongate member 14 is positioned within lower chamber 39 which contains no confection, since central body portion 16 seals confection from lower chamber 39. Upon removal of conical container 30, the confection is supported by elongate member 12 and central body portion 16. The curved periphery of elongate member 14 may be grasped between the thumb and forefinger of the consumer to hold the confection in position during its consumption. FIG. 5 illustrates an alternate embodiment of a symmetrical holding device generally identified by the numeral 40. Symmetrical holding device 40 consists of a central body portion 46 shaped as a thin circular disk. Central body portion 46 has an annular surface 48 for engaging the inner walls of conical container 30. Elongate members 42 and 44 are symmetrical about and perpendicular to the annular surface 48 of central body portion 46. Elongate members 42 and 44 are shaped as hexagonal rods of relatively small uniform cross section throughout the length of each. The hexagonally shaped rods provide a rigid structure as a means for elongate member 42 to support confection and for elongate member 44 to be grasped between the thumb and forefinger as a handle. The hexagonal shape of the rod reduces slippage of the handle in the hand of the consumer. Elongate members 42 and 44 have ends 52 and 53, respectively, with hexagonal cross section. FIG. 6 is another alternate embodiment of a symmetrical holding device generally identified by the numeral 60. The central body portion 66 is a sphere with annular surface 68 around the middle of the sphere for engaging the inner surface of conical container 30. Elongate members 62 and 64 are symmetrical about and perpendicular to the annular surface 68 and are integrally attahed to sphere 66. Elongate members 62 ad 64 are shaped as cylindrical rods of uniform cross section. Elongate members 62 and 64 have circular ends 72 and 74, respectively. It will be understood that devices may be constructed from any suitable material, but preferably made from plastic. It will be further understood that an elongate member may vary in cross sectional shape, or it may be of non-uniform cross section throughout its length. Although preferred embodiments of the invention have been illustrated in the accompanying drawings and described in the foregoing detailed description, it will be understood that the invention is not limited to the embodiments disclosed, they are capable of numerous rearrangements, modifications, and substitutions of parts and elements without departing from the spirit of the invention.

The specification discloses a confection holding device having a central body with an annular surface and two rigid symmetrical elongate members integrally attached to and perpendicularly extending from opposite sides of the central body. The symmetry of the holding device allows it to be mechanically inserted in a conical container without regard to its orientation. The annular surface of the central body engages the inner walls of a conical container, defining an upper chamber into which a confection may be placed. The central body and the upper elongate member support the body of a confection when the conical container is removed. The lower elongate member is held by the consumer as a handle to support the confection during consumption.

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation of U.S. patent application Ser. No. 11/936,037, filed Nov. 6, 2007, which is hereby incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] Embodiments of the present invention relate generally to video processing and more specifically to a method and system for blending rendered images from multiple applications. [0004] 2. Description of the Related Art [0005] Unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section. [0006] To enhance a user's viewing experience of computer-generated images, more and more computing devices are relying on a dedicated graphics subsystem with not one but multiple graphics processing units (“GPUs”) to perform rendering operations. The GPUs can be configured to perform operations such as split frame rendering (“SFR”) or alternate frame rendering (“AFR”) to scale up the number of pixels computed by the graphics subsystem. The GPUs can also be configured to efficiently perform anti-aliasing (“AA”) operations to improve image quality. Some of the conventional usage models involving multiple GPUs are shown in FIG. 1 . [0007] To illustrate, suppose there are two GPUs, GPU 0 and GPU 1 in the graphics subsystem. Under the usage model 1 , both the GPU 0 and GPU 1 are configured to carry out the rendering operations associated with the same application and scan out the rendered images to the only display device that is attached to the computing device and recognized by both the application and also the operating system executing on the computing device. The aforementioned SFR and AFR operations typically fall under this usage model 1 . Under the usage model 2 , each of GPU 0 and GPU 1 is attached to a distinct display device. Here, even though there are physically two GPUs and two display devices, the application and also the operating system executing on the computing device still only recognize one GPU and one display device. Each GPU is configured to compute one half of the surface that is being rendered and scan out the rendered images to its attached display device. The usage model 3 is similar to the usage model 1 , except one of the GPUs is designated to pull, blend, and scan out the blended results associated with the same frame and also the same application to the display device. The AA operation discussed above generally falls under this usage model 3 . [0008] As the foregoing illustrates, none of the usage models shown in FIG. 1 and described above permits the multiple GPUs to perform operations for different applications and still scan out the rendered images to a single display device. Thus, especially for a user with access to a single display device but with needs to maneuver multiple graphics-intensive operations, what is needed is a way to blend rendered images from multiple applications. SUMMARY OF THE INVENTION [0009] A method and system for blending rendered images from multiple applications are disclosed. One embodiment of the present invention sets forth a method, which includes the steps of generating a first rendered image associated with a first application, independently generating a second rendered image associated with a second application, applying a first set of blending weights to the first rendered image to establish a first weighted image, applying a second set of blending weights to the second rendered image to establish a second weighted image, and blending the first weighted image and the second weighted image before scanning out a blended result to a first display device. [0010] One advantage of the disclosed method and system is to enable high quality images from multiple applications to be displayed on a single display device cost effectively. BRIEF DESCRIPTION OF THE DRAWINGS [0011] So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. [0012] FIG. 1 is a table illustrating some conventional usage models involving multiple GPUs; [0013] FIG. 2A is a flow chart illustrating the method steps of preparing for the blending of rendered images from multiple applications that are executing on a computing device in a picture on picture mode, according to one embodiment of the present invention; [0014] FIG. 2B illustrates an example of blending images from two different applications, according to one embodiment of the present invention; [0015] FIG. 3 is a block diagram of a computing device with a video bridge configured to implement one or more aspects of the present invention; [0016] FIG. 4A is a block diagram of another computing device also configured to implement one or more aspects of the present invention; and [0017] FIG. 4B illustrates a simplified process of blending rendered images from different applications without a specialized hardware unit, according to one embodiment of the present invention. DETAILED DESCRIPTION [0018] FIG. 2A is a flow chart illustrating the method steps of preparing for the blending of rendered images from multiple applications that are executing on a computing device in a picture on picture mode, according to one embodiment of the present invention. Suppose this computing device is a laptop computer coupled to a docking station. The laptop computer includes a primary GPU, GPU 0 , which resides in a first graphics adapter, and the docking station includes a secondary GPU, GPU 1 , which resides in a second graphics adapter. The first graphics adapter is further attached to a first display device. Once the computing device is configured to operate in the picture-on-picture mode, although only one display device is attached to the graphics adapters, in step 200 , the operating system executing on this computing device is informed that there are two GPUs, two graphics adapters, and two display devices attached to the graphics adapters. In one implementation, a driver associated with the graphics subsystem in the computing device intercepts the actual graphics resource information reported by the hardware components and provides the operating system with this specifically tailored graphics resource information. Even if the second graphics adapter is also attached to a second display device, one implementation of the driver still ensures that the GPU 1 transmits the rendered images to the GPU 0 to be scanned out to the first display device. [0019] According to one aspect of the present invention, the two GPUs are configured to generate graphics images with the same screen resolution. Thus, if the screen resolution supported by the primary GPU, such as the GPU 0 , is detected to have changed in step 202 , then one implementation of the driver imposes the newly changed screen resolution requirement on the secondary GPU, such as the GPU 1 , in step 204 . On the other hand, if the screen resolution supported by the primary GPU remains unchanged, then whether there is a request to modify the blending weights is checked in step 206 . Blending weights are primarily used to vary the visual effects of the images from different applications on the display device. Subsequent paragraphs will provide some examples illustrating the use of the blending weights. If the modification request is indeed detected in step 206 , then the blending weights are modified and stored in step 208 . In one implementation, the modified blending weights are stored in the registers of a video bridge. In addition, the various sets of blending weights can be associated with hotkeys. In particular, a hotkey can be a specific key or a combination of keys used in a specific sequence to represent a certain set of pre-determined blending weights. In other words, by switching from one hot key to another, the blending weights can be modified dynamically. In step 210 , the blending weights are applied to the rendered images generated by the GPUs, and these weighted images are blended. [0020] In conjunction with FIG. 2A and the discussions above, FIG. 2B illustrates an example of blending images from two different applications, according to one embodiment of the present invention. Suppose a first screen 220 includes a display window 222 showing images from an application A (e.g., a video conference session) and also the desktop of the display window 222 (e.g., the desktop of an operating system) supported by the GPU 0 , and a second screen 224 fully displays images from an application B (e.g., a game) supported by the GPU 1 . Suppose no weight is assigned to the desktop of the display window 222 ; weight A is assigned to the images from the application A, and weight B is assigned to the images from the application B. After the blending step of 210 , a resulting screen 226 is likely to show both the display window 222 with the images rendered by the GPU 0 and also the entire screen 224 with the images rendered by the GPU 1 . Due to the zero weight, the initial desktop of the screen 220 does not contribute to the resulting screen 226 . The same region on the screen 226 corresponding to the display window 222 in the screen 220 , on the other hand, includes the blended results of [(weight A * images from application A)+(weight B * images from application B)]/divider. Thus, if the images from application A are meant to display more prominently in the foreground, then the weight A is configured to be greater than the weight B . On the other hand, if the images from the application B should instead display more prominently in the foreground, then the weight B is configured to be greater than the weight A . Any numerical value assigned to the divider is used to further modify the effects of the different weights. [0021] Moreover, one way to modify these weights is through the use of hotkeys. In one implementation, a hotkey may be configured to showing the images from the application A only on the screen 226 (i.e., using this hot key results in setting the weight A to 1 and zeroing out all the other weights); another hotkey may be configured to showing the images from the application B only (i.e., using this hotkey results in setting the weight B to 1 and zeroing out all the other weights); and yet another hotkey may be configured to showing the images from both of the applications A and B (i.e., using this hotkey results in setting the weight A and weight B to non-zero values). [0022] In one implementation, the blending of the weighted images from multiple applications is performed by a specialized hardware component, such as a video bridge blending logic. FIG. 3 is a block diagram of a computing device with the video bridge configured to implement one or more aspects of the present invention. Without limitation, the computing device 300 may be a desktop computer, server, laptop computer, palm-sized computer, tablet computer, game console, cellular telephone, hand-held device, mobile device, computer based simulator, or the like. The computing device 300 may also include a docking system. The computing device 300 includes a host processor 308 , BIOS 310 , system memory 302 , and a chipset 312 that is directly coupled to a graphics subsystem 314 . BIOS 310 is a program stored in read only memory (“ROM”) or flash memory that is run at bootup. The graphics subsystem 314 includes a first and a second graphics adapters 315 and 317 , each with a single GPU, namely primary GPU 326 and secondary GPU 332 , respectively. If the computing device 300 is a laptop computer coupled to a docking system, then the primary GPU 326 resides in the laptop computer, and the secondary GPU 332 resides in the docking system. [0023] A graphics driver 304 , stored within the system memory 302 , configures the primary GPU 326 and the secondary GPU 332 to independently communicate with the two distinct applications that are executed by the host processor 308 . In one embodiment, the graphics driver 304 generates and places a stream of commands in a “push buffer,” which is then transmitted to the GPUs. When the commands are executed, certain tasks, which are defined by the commands, are carried out by the GPUs. [0024] In some embodiments of the computing device 300 , the chipset 312 provides interfaces to the host processor 308 , memory devices, storage devices, graphics devices, input/output (“I/O”) devices, media playback devices, network devices, and the like. Some examples of the interfaces include, without limitation, Advanced Technology Attachment (“ATA”) bus, Accelerated Graphics Port (“AGP”), Universal Serial Bus (“USB”), Peripheral Component Interface (“PCI”), and PCI-Express®. It should be apparent to a person skilled in the art to implement the chipset 312 in two or more discrete devices, each of which supporting a distinct set of interfaces. [0025] Connections 318 , 322 , and 324 support symmetric communication links, such as, without limitation, PCI-Express®. A “symmetric” communication link here refers to any two-way link with substantially identical or identical downstream and upstream data transmission speed. A connection 320 can be any technically feasible scalable bus that provides a direct connection between the primary GPU 326 and the secondary GPU 332 . One embodiment of the connection 320 can be implemented using the NVIDIA® SLI™ multi-GPU technology. The computing device 300 further includes a video bridge 316 , which not only provides an interface between the chipset 312 and each of the primary GPU 326 and the secondary GPU 332 via the connection 322 and the connection 324 , respectively, but the video bridge 316 also provides an interface between the primary GPU 326 and the secondary GPU 332 through the combination of the connections 322 and 324 and bypassing the chipset 312 . Moreover, the video bridge 316 includes the blending logic to apply the appropriate weights to the rendered images and blend the weighted images. [0026] As shown, the primary GPU 326 within the first graphics adapter 315 is responsible for outputting image data to a display device 338 . The display device 338 may include one or more display devices, such as, without limitation, a cathode ray tube (“CRT”), liquid crystal display (“LCD”), plasma display device, or the like. The primary GPU 326 is also coupled to video memory 328 , which may be used to store image data and program instructions. The secondary GPU 332 within the second graphics adapter 317 is also coupled to video memory 334 , which may also be used to store image data and program instructions. The primary GPU 326 does not have to be functionally identical to the secondary GPU 332 . In addition, the sizes of the video memories 328 and 334 and how they are utilized by the first and second graphics adapters 315 and 317 , respectively, do not have to be identical. [0027] To illustrate the aforementioned blending operation in the computing device 300 , suppose the primary GPU 326 performs rendering operations for an application A, and the secondary GPU 332 performs rendering operations for an application B. When the secondary GPU 332 renders a frame, it pushes the rendered image associated with the application B from a secondary frame buffer in video memory 334 to the video bridge 316 . Similarly, the primary GPU 326 also pushes the rendered image associated with the application A from a primary frame buffer in video memory 328 to the video bridge 316 . The blending logic in the video bridge 316 then retrieves the blending weights stored in the registers of the video bridge 316 , applies the appropriate blending weights to both of these rendered images, and blends the weighted images. In one implementation, the blended results are stored in the video memory 328 for the primary GPU 326 to scan out to the display device 338 . It should be noted that the graphics subsystem 314 in this implementation neither depends on the resources of the chipset 312 nor the GPUs to carry out the blending operation. [0028] According to an alternative embodiment of the present invention, a computing device 400 as shown in FIG. 4A with multiple GPUs but without a video bridge and the hardware blending logic can still be configured to perform the aforementioned blending operation. Specifically, FIG. 4B illustrates a simplified process of blending rendered images from different applications without a specialized hardware unit, according to one embodiment of the present invention. Using the computing device 400 to illustrate such a process, the primary GPU 426 and the secondary GPU 432 perform the rendering operations associated with two different applications independently in steps 450 and 452 , respectively. In one implementation, the computing device 400 allocates a block of memory from system memory 402 for use as a temporary buffer 406 . When a secondary GPU 432 renders a frame associated with the application B, the application B requests to flip this rendered frame by transmitting it to the temporary buffer 406 in step 454 . After the primary GPU 426 renders the frame associated with the application A, it then pulls the rendered image from the temporary buffer 406 , applies the appropriate blending weights to the two rendered images, and blends the two weighted images in step 456 . Here, the primary GPU 426 treats the rendered frame from the secondary GPU 432 as texture. In one implementation, the primary GPU 426 stores the blended results in a primary frame buffer in video memory 428 to be scanned out to a display device 438 . It should be noted that the resources of the chipset 412 and also the primary GPU 426 in this implementation are utilized to carry out the blending operation. [0029] In yet another alternative implementation, instead of pushing the rendered image to the system memory 402 , the secondary GPU 432 can push the rendered image to the primary frame buffer in the video memory 428 through connections 422 , 424 , and chipset 412 or through connection 420 directly in step 454 . Similar to the computing device 300 described above, the connections 422 and 424 support symmetric communication links, such as, without limitation, PCI-Express®, and the connection 420 can be any technically feasible scalable bus that provides a direct connection between the primary GPU 426 and the secondary GPU 432 . [0030] It is worth noting that in one implementation, the primary GPU 426 and the secondary GPU 432 are synchronized before proceeding to step 456 . It should be apparent to a person with ordinary skills in the art to apply any synchronization scheme (e.g., semaphores) without exceeding the scope of the present invention. Furthermore, although the graphics subsystems 314 and 414 of systems 300 and 400 , respectively, are shown to provide certain graphics processing capabilities, alternative embodiments of these graphics subsystems may process additional types of data, such as audio data, multimedia data, or the like. [0031] The above description illustrates various embodiments of the present invention along with examples of how aspects of the present invention may be implemented. The above examples, embodiments, and drawings should not be deemed to be the only embodiments, and are presented to illustrate the flexibility and advantages of the present invention as defined by the following claims.

One embodiment of the present invention sets forth a method, which includes the steps of generating a first rendered image associated with a first application, independently generating a second rendered image associated with a second application, applying a first set of blending weights to the first rendered image to establish a first weighted image, applying a second set of blending weights to the second rendered image to establish a second weighted image, and blending the first weighted image and the second weighted image before scanning out a blended result to a first display device.

This invention was made with Government support under Contract No. NAS7-1260 awarded by the National Aeronautics and Space Administration. The Government has certain rights in this invention. FIELD OF THE INVENTION This invention relates to millimeter wave devices, and, more particularly, to a housing or package for such devices. BACKGROUND Millimeter wave devices employ a monolithic microwave integrated circuit device or “MMIC” as an active element and operate at very high frequencies, 45 Gigahertz to 120 Gigahertz and higher. The devices may be configured as amplifiers, oscillators and the like electronic devices to perform functions at those high frequencies akin to those functions accomplished at lower frequencies with more familiar amplifier and oscillator architecture. Such millimeter wave devices find application, as example, in MMW radiometers. The elements of the device are physically quite small. At a frequency of 120 Ghz, one wavelength measures a mere one-quarter of a centimeter in length or slightly less than one-tenth of an inch. MMW devices thus are physically small in size, and its components, including one or more MMIC's, are much smaller still. Although small in size, unlike lower frequency apparatus, the physical dimension of the MMIC, the associated electronic components and the electrical lead wires are large in respect to the wavelength of the operating frequencies. As a consequence lead wires and the like, by which the components are wired into circuit, and even the body of the component can impact the electromagnetic characteristics of the electronic circuit defined with those elements. Thus the development of a new MMW device and the proof of the device's design is complicated by that impact. For one, it is necessary to shield the device's components and/or electrical leads. Thus it is not possible to mount all the circuit components and MIMICS on a conventional printed circuit board or place the device in a conventional housing, such as used at lower frequencies. The MMW signals in one part of the circuit must be limited to propagating only to precisely defined routes and must not “jump” that route and propagate in undesired ways to parts of the circuit where they would cause interference. As example, because the wavelength is so short, a small electrical lead from a component or interconnection may serve as a full wave or half-wave antenna, and radiate MMW energy from that lead into open space. Other electrical leads in the circuit could likewise act as a full-wave or half-wave receiving antenna, picking up the foregoing radiation. As more specific example, in the familiar superheterodyne type receiver, a mixer receives MMW energy from an external source and mixes the received signal with another MMW signal supplied by a local oscillator to produce a lower difference frequency or “beat” signal, as variously termed, a process called down-converting. The downconverted signal is then coupled to an IF amplifier, which amplifies that signal. If, however, through the spurious radiation process described, the MMW signal is also coupled to the output of that mixer by means of a spurious path, the mixer's output contains not only the IF signal, but an interfering MMW signal. The combination of those two signals may overload the succeeding IF amplifier. Then too, the two signals may beat together in the IF amplifier creating still additional interference signals. To avoid such spurious signals, it is necessary to essentially shield each component from every other component in the MMW device. The MMW device's housing or packaging provides that shielding. Thus, to house the active MMIC semiconductor device and the ancillary capacitors and resistors, the practice has been to use a thick metal plate that has been machined to form precisely defined compartments or hollow cavities, referred to as “mouseholes”, within the plate's thickness or depth, and provide additional small passages for the interconnecting leads to those elements. The mouseholes are small and narrow, consistent with the small physical size of the components. The active MMIC devices are formed on substrates. And the MMIC devices and the other electrical components are dropped into their respective mousehole, and fastened in place, suitably with an epoxy adhesive. The open side of the housing is covered with a metal lid, closing the mouseholes. Typically, machining of the housing to shape is accomplished using Electron Discharge Machining apparatus. That apparatus has the ability to maintain very tight dimensional tolerances and produces cavities with sharply defined square corners, which is desirable. However, discharge machining is an expensive process. As is familiar to designers of microwave and higher frequency devices, the foregoing assembly of MMW elements into the foregoing package on initial assembly of the first or prototype unit rarely, if ever, produces MMW device performance that conforms to the theoretical operation desired. Although the foregoing package solves one problem, it produces others: the cavity mode resonances. The adverse effects are due to the fact that the dimensions of the formed cavities, the mouseholes, are all on the same order as the wavelength of those frequencies for which the device is intended to function. Recalling that at 120 MHz, the wavelength is only one-tenth inch and that portions of the electrical leads are located within those cavities, the lead portion again act as an antenna or coupling and the energy radiated therefrom “excites” one or more electromagnetic modes within the respective mouseholes. A rectangular cavity is capable of supporting, that is, resonating in a number of different modes, including a primary TE01 mode and an indefinite number of higher order modes. The higher the number of the mode, the lower the maximum amplitude of the voltage or intensity. Exact mathematical representations of those modes for a given cavity are available in the technical literature. Any excited mode could cause interference and is undesirable and should be minimized or eliminated entirely. Although foreseeable, because of the complex nature of mode excitation and lead placement and the shape of the mouseholes, the precise cause of the adverse effects are unpredictable. To the present day, neither close attention to detail in fabricating the completed package or refinement in design procedures have been able to eliminate those effects. As a practical matter, the adverse effects come with the territory. Thus, following assembly of a prototype MMW device, the procedure is to hunt down and destroy those expected uninvited resonances. This is presently accomplished by inserting high frequency absorbent, “lossy”, material, such as Eccosorb material, at strategic locations in the cavities. The Eccosorb material produces an electrical loss to the incident radiation, thereby reducing or minimizing the offending mode or modes. Although intended to be identical in construction, in the absolute sense each MMW device in a production run differs in physically minute respects from others in the run. An electrical lead from a component in one device may be oriented slightly in position from the corresponding lead in the corresponding component in the next device, creating a small physical difference. However, measured against the wavelength of the frequencies employed, which is, as earlier stated, one-quarter centimeter at 120 GHz, the difference is significant. That difference results in the excitation of a different mode during operation. Thus each device produced in the run must be tested and the unique resonant modes hunted down and destroyed. Typically the design of a MMW device is confirmed or “proofed” with the production of the first prototype. Often one finds that it is not possible to sufficiently minimize the unwanted resonances in that production prototype. One must refine the design of the mousehole cavities and, essentially, construct a second iteration of a prototype. Since the components are all permanently fastened in place in the first prototype, and are nearly impossible to remove without damaging the device or the housing, one is left with the prospect of rebuilding the next prototype from scratch. That procedure means repeating the expensive machining procedure to form another metal housing and using up additional valuable MMIC devices. The foregoing is an obvious drain on resources, including manpower, and diverts those resources from more intellectually interesting goals. It begs for a more efficient and streamlined prototyping technique. MMW devices, such as radiometers, are produced in very very limited quantities and is by no means regarded as a high volume product. Thus quite often fewer than half a dozen in total are produced for a customer. If two or more prototypes need to be produced in order to attain the stage of desired performance, performance that excludes the unwanted resonances, the added development expense can be amortized only over the production run of six, in the example given. And that significantly raises the ultimate per unit cost of MMW devices in the production run. Accordingly, a principal object of the invention is to simplify and more efficiently develop microwave millimeter wave devices. A further object of the invention is to provide a new housing or package that simplifies construction of satisfactory prototype millimeter microwave devices. An additional object of the invention is to easily eliminate excitation of unwanted cavity resonances in the housing mouseholes of the MMW device. A still further object of the invention is to develop MMW devices without requiring repetitious reconstruction of machined housing packages. SUMMARY OF THE INVENTION In accordance with the foregoing objects a package for a high frequency electronic device that employs one or more MMIC devices is formed of a base plate and a plurality of metal inserts removeably fastened to the base plate. The inserts are spaced apart and contain a profiled edge with the profiled edge in one in confronting spaced relationship with that of another of the inserts. Together with the backplate, the profiled edges define elongated cavities with the edges serving as two of the cavities side walls. The foregoing cavities serve as a repository for the MMIC devices and some of the additional components and stripline. The side walls capture at least a portion of the discrete components, including capacitors, resistors, MMIC's. As an additional aspect, passages are also formed through the inserts, spaced from the profiled edges, to serve as compartments for containment of additional electronic components and allowing those components to be secured directly to the back plate. Shallow grooves defined in the underside surface of the inserts provide passages between the compartment and the cavity, permitting electrical leads from the components to connect with other components and/or MMIC devices installed in the cavity. The foregoing invention eliminates the need inherent in the prior MMW device packaging of placing substrates and other electronic components into vary narrow cavities, mouseholes, formed in the packaging to prevent appearance of higher order cavity resonances. With the invention, the RF and DC components of the MMW device are placed directly in the module, which reduces the MMW device's assembly time. The cavity size is determined by the dimensions of the metal insert, not, as in the prior devices, by a cavity machined into the integrated module assembly (IMA) housing. Tight dimensional tolerances requiring electron discharge machining apparatus characteristic of the prior MMIC housings are eliminated. The foregoing construction permits easy re-machining or replacement of an improperly sized or out of tolerance cavity. Following adhesive fastening of the MMIC's, substrates, and other electronic components in place in the housing, the metal inserts can be removed, remachined, and reinstalled allowing adjustment of the cavity size to eliminate undesired cavity oscillations that may have been introduced by installation those electronic components. The MMIC's, substrates and other electronic components remain in place undisturbed on the housing during such adjustment. The foregoing and additional objects and advantages of the invention together with the structure characteristic thereof, which was only briefly summarized in the foregoing passages, becomes more apparent to those skilled in the art upon reading the detailed description of a preferred embodiment, which follows in this specification, taken together with the illustration thereof presented in the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS In the drawings: FIG. 1 shows the new package in an exploded view; FIG. 2 shows three of the elements of the embodiment of FIG. 1 in assembled relationship in top view; FIG. 3 shows the elements of FIG. 2 in a bottom view; FIG. 4 illustrates a bottom view of the cover used in the foregoing embodiment; FIG. 5 is a block diagram of the radiometer front end that is to be housed in the package of FIGS. 1-4, identifying the various electronic functions of the components; and FIG. 6 is an enlarged partial view of one of the elements shown in FIGS. 2 and 3 used to assist the reader to understand a benefit of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A MMW device package is best described in connection with a radiometer application, more particularly a front end unit for a radiometer, such as illustrated in exploded view in FIG. 1 . The package contains a metal base or base plate 1 , three smaller individual plates, referred to as inserts, 3 , 5 , and 7 , and, optionally, a metal cover plate or cover 9 , which, as assembled, are sandwiched together in a unitary assembly. The inserts, though physically separate from one another, are illustrated arranged in a common plane, as they would appear when assembled to base plate 1 , with confronting edges spaced from each other. Base plate 1 contains six small cylindrical shaped guide pins 11 , 13 , and 15 , suitably two guide pins for each of the three inserts to aid in positioning the inserts on the surface of the base plate. Each of the inserts contains guide holes extending through the insert's thickness, such as guide holes 12 in insert 3 , guide holes 14 in insert 5 and guide holes 16 in insert 7 . By design those guide holes correspond in spacing and position with associated guide pins on the base plate. Ideally those guide pins are located to an accuracy of one mil or better and enter the guide holes in the inserts with a slip fit. To fasten the inserts in place, the base plate also contains a series of threaded bolt passages 19 , 21 , and 23 , suitably three for each of the inserts. The inserts contain bolt passages there through at locations that correspond in spacing and position with associated threaded bolt passages on the base plate. Thus bolt holes 20 are included in insert 3 , bolt holes 22 are contained in insert 5 and bolt holes 24 in insert 7 . Suitably the top end of those bolt passages is of wider diameter to accommodate and receive the bolt head in order that the bolt head does not protrude above the upper surface of the associated insert. With the inserts positioned on the associated guide pins in the base plate, bolts 9 , only one of which is illustrated, are screwed into place to securely fasten the inserts in place to the base plate. This is a removable fastening, which is used to advantage to permit the insert to be removed and replaced, as later herein described. Following installation of all electrical components and MMIC' devices, not illustrated, but later herein discussed, onto the base plate and fastening down of the inserts, the cover 9 is welded in place atop the inserts. For in-flight use in a radiometer, the cover, alternatively, may be screwed to those inserts, in which case the inserts would be modified to incorporate threaded bolt holes on the upper surface. The cover provides a shield at the open side of the cavities for the enclosed electronic components. As assembled, the three inserts are spaced apart from each other on the upper surface of base plate 1 , with the confronting side edges of those inserts defining therewith three passages or cavities 27 , 29 and 31 that intersect at a junction. This is better illustrated in the top and bottom views of FIGS. 2 and 3, next considered. Reference is made to the top view of FIG. 2, which shows the three inserts 3 , 5 , and 7 in assembled relationship, properly spaced. Cavity 27 is defined between the confronting spaced edges 28 and 30 , of inserts 3 and 5 , respectively. Another cavity 31 is defined between the confronting spaced edges 32 and 34 of inserts 5 and 7 , respectively. And the third cavity 31 is defined between the confronting spaced edges 38 and 40 of inserts 7 and 3 , respectively. Those confronting insert edges bordering portions of the inserts periphery are contoured or profiled, as variously termed, and serve as cavity walls to the adjoining cavity. Those walls are parallel to one another and, when assembled, are perpendicular to the base plate surface, the latter of which serves as a bottom cavity wall. By design the guide pins in the base plate are perpendicular to the surface of the base plate in order to maintain the profiled edges of the inserts in parallel and oriented perpendicular to the base plate. The cavity's height is essentially equal to the thickness or depth of the inserts, which are preferably of equal thickness. The cited cavities intersect at a common junction or location as illustrated. Although the elongate cavities are made as narrow as possible to accommodate microwave strip line conductors, the cavity is widened at various locations along its length, as example at 41 where a complementary rectangular shape slots in opposed edges of the inserts define a wide rectangular area in cavity 27 . This wider area is necessary to physically accommodate a MMIC chip, which is larger in size than the narrow portion. In this embodiment, cavity 27 contains three additional wide rectangular shaped spaces. Likewise, cavity 31 accommodates three MMIC amplifiers in respective ones of the three rectangular spaces, such as 43 , and cavity 29 contains two such large rectangular spaces, such as 45 . As earlier mentioned, the housing is for a front end of a radiometer, illustrated in FIG. 5, later discussed, and that front end includes a mixer, an active MMIC element. That mixer is positioned at the intersection of the three cavities, enabling the mixer to receive RF signals inputted via cavities 27 and 29 , and provide an output into cavity 31 . To accommodate that mixer, the ends of the three cavities are also widened sufficiently. Guide pins 11 properly locate insert 3 on the base plate relative to the other inserts. Likewise guide pins 13 properly locate insert 5 and guide pins 15 properly located insert 7 to the requisite position and spacing, wherein the width of the passage is of the desired dimension. The inserts are then screwed into place. In addition to forming the cavity wall, the inserts also contain cut-out sections or, as variously termed, large sized through-hole passages to provide pockets or compartments in which to mount the bypass capacitors and resistors that set the bias conditions for the respective MMIC chips installed in the respective cavities. Insert 1 contains compartment 42 , 44 , 46 and 48 and also a large rectangular compartment 50 . Insert 4 in this embodiment contains five compartments 52 , only one of which is numbered, and insert 7 contains one compartment 54 . The compartments extend through the insert, from top to bottom. As shown in the bottom view of FIG. 3 to which reference is made, those compartments open on the bottom side, allowing the upper surface of base plate 1 , when assembled to the inserts, to serve as the compartment's floor. As is visible in FIG. 3, a short shallow narrow groove 49 formed on the underside of insert 3 extends between compartment 44 and elongated cavity 27 . The groove serves as a passage for the electrical leads from the component disposed within compartment 44 and those components or devices located within the elongated cavity. With the component installed in the portion of the baseplate 1 that underlies compartment 44 in insert 3 , its electrical leads are routed through the groove passage 49 to an appropriate electrical connection on the associated MMIC chip that is disposed in the cavity 27 . To the left, three lead grooves, only one of which 56 is labeled, extend between compartment 50 and spaced positions along elongated cavity 31 . Other like grooves extend between the other compartments illustrated and the adjacent cavity and serve like function. Thus lead groove 51 is associated with compartment 52 in insert 5 , and additional lead passages, not numbered extend between the illustrated compartments, not numbered in insert 3 and cavity 27 . Along the side of insert 5 , lead groove 53 extends between compartment 52 and cavity 29 , and another like groove, spaced therefrom also extends between another side of that compartment and cavity 29 . Insert 7 contains a lead groove 55 extending between compartment 54 and cavity 29 . Returning to FIG. 1, the inserts collectively fit within the upper surface area of base plate 1 . Apart from the profiled edge along two portions of the inserts periphery, the outer periphery of insert 3 is straight so as to be flush with outer edges of the base plate, which is rectangular shape in this embodiment. Likewise two of the edges insert 5 and two of insert 5 are also straight and oriented at right angles to one another for the same reason. With cover 9 , the inserts and the base plate sandwiched together, the package defines a rectangular geometry of short height that may be fitted within a predefined slot-like compartment in other equipment, not illustrated. Reference is made to FIG. 4, providing a view of the underside of cover 9 . Ideally, the top and bottom side surfaces of cover 9 should be flat. However, when, as in the present embodiment, it is desired to limit the total thickness or height of the package to a predetermined dimension governed by space available in the external equipment, the thickness or height of the inserts 3 , 5 and 7 might be smaller than the height of the MMIC devices installed in some of the compartments, such as those MMIC devices disposed in compartments 41 in passage 27 and compartments 34 in passage 29 , shown to the left in FIG. 2 . To accommodate that excess in the component's height, appropriate grooves are formed in the underside surface of cover 9 . Thus, as illustrated, the cover contains an elongate cavity 27 ′ containing compartments 41 ′ and an elongate cavity 29 ′, which insects cavity 27 ′, containing compartments 34 ′ formed by shallow grooves. For convenience the foregoing cavities are identified by the same numbers as the corresponding cavities and compartments defined in inserts 3 and 5 in FIG. 2, but primed. The foregoing cavities and their included compartments formed in the cover overlay and cover the mating cavities and compartments defined in inserts 3 and 5 . This may be visualized by inverting FIG. 4 and applying it over the top view of the inserts in FIG. 2 . Suitably, the metal used to form the foregoing base plate, inserts and cover is the well known A-40 material, an aluminum silicon compound, which is light in weight, of high thermal conductivity and is easily machined. That material also allows direct attachment of MMIC chips and fused silica substrates directly to the floor of the housing, the base plate. Preferably the A-40 metal is plated with a Nickel Gold plating, a Nickel layer followed by a Gold layer overlay to enhance the surface's electrical conductivity. Returning to FIG. 2, it is appreciated that the projection of the three inserts 3 , 5 and 7 onto the base plate 1 defines a pattern for the regions of the base plate left uncovered, the regions underlying the component compartments and the elongated cavities. That pattern may be marked onto base plate 1 in any convenient way. Further, the foregoing pattern may be enhanced by manually adding to it, the outline of the various lead grooves, earlier described in connection with FIG. 3 formed on the back side of the inserts. With that pattern, the electrical components, MMIC devices and leads may be directly installed in place on the base plate 1 within the regions of the pattern defined by the outlines of the respective compartments, cavities and grooves. The RF/DC bias circuitry and local oscillator components are all located on the same side of the housing. The technician may assemble and wire bond those elements together in circuit without being physically constrained by the side edges or compartment walls of the inserts. Thus wire bonders may easily be positioned and used to wire bond electrical components in the desired circuit arrangement. Thereafter the inserts may be placed in position and fastened in place, making minor adjustments as necessary to the position of the leads. Alternatively, the technician may install one or more of the inserts in place and then mount the components, MMIC chips and leads in place. An initial benefit of the foregoing construction is apparent. The compartments expose an area of the underlying base plate. That exposed area or floor serves as a fastening location for the electrical components located in the compartment. The components are typically adhesively joined by epoxy to the exposed base plate area underlying the associated pocket firmly holding the components in place. Once bonded, removal of the components is very difficult. The electrical leads from those components are extended into the cavity area through the bottomless lead grooves. Should it be desired to remove the insert for any reason, such as elsewhere herein discussed, once the screws attaching the insert to the base plate are removed, the insert may be lifted off of the base plate, leaving the electrical component and leads undisturbed and in place. The insert may thereafter be replaced in position and screwed back in place as those components and leads remain in proper alignment with the openings in the insert. The foregoing housing construction offers faster and more efficient assembly operation. The technician need only place a pattern of the cavities, pockets and lead routings on the base plate, and then proceed to mount all of the electronic components and stripline within the confines of that pattern, including bonding all the electrical connections. Thereafter, the technician may install the inserts in place. With the new package, the technician is no longer burdened by the tedious and time consuming task of wire bonding connections in physically small mouseholes using wire bonders not designed for that purpose. It is found that the smallest size wire bonder tip available is still larger than desired for the small size confines of a mousehole; and due to the lack of volume production of MMW devices using the prior housing design, no incentive for the wire bonder manufacturer to develop physically smaller bonding tips and make them available at a reasonable price. Working with existing wire bonders in MMW device application required the technician to shoulder a near impossible burden. The present invention avoids that problem, making MMW device manufacture quicker and more efficient. A front end circuit 60 for a MMW radiometer is schematically illustrated in FIG. 5, surrounded by dash lines, together with a local oscillator module 61 in an adjacent block. Typically the radiometer's front end includes an input 62 for the received MMW signal, a low noise amplifier 63 , which comprises one or more amplifier stages, a band pass filter 64 x, a sub-harmonic mixer 65 , a local oscillator input 66 for receiving a local oscillator signal from oscillator module 61 , an amplifier 67 for that signal, whose output is coupled to a mixer input, an IF amplifier 68 , comprising one or more IF amplifier stages. In operation the signal received at input 62 is amplified, filtered and applied to one input of mixer 65 . The mixer mixes or beats that signal together with the local oscillator signal from input 66 , producing, for one, a signal of a frequency that is equal to the difference in frequency between the former to signals, called the IF signal. That IF signal is amplified and routed to output 69 , from where it is fed to other signal processing circuits, not illustrated, of the radiometer. It is appreciated that the foregoing circuit illustrates a classic frequency downconversion system. As earlier noted should the housing for the circuit be such that the signal at input 62 finds an alternative path to amplifier 68 , or should the signals from any of the devices excite a cavity mode to produce another signal, either such signal could interfere with proper operation of the mixer 65 and/or IF amplifier 68 . The mechanical aspects of the device's housing ideally must not permit the creation of adverse electromagnetic effects or should any such adverse be created, it should be easily absorbed through introduction of microwave loss material, such as Eccosorb material, into the housing. The disclosed housing satisfies that criteria. To develop an electronic device at the high frequencies employing MMIC devices, such as the radiometer front end depicted in FIG. 5, the designer determines the number of electronic components needed and ancillary thereto the size of the cavities and compartments needed in the housing. The housing is then fabricated, resulting in an initial configuration of the back plate, inserts and cover. The components are assembled together into the housing in any of the procedures earlier described. The design is then tested, recognizing that the goal is to finalize a design both electrically and physically that may be later reproduced in larger quantities. Should any undesired resonances be uncovered during test, it requires the judgment and skill of the designer to uncover its cause. Obviously, the procedure for doing so is not material to the present invention and goes beyond the scope of the specification. Accordingly, it is possible only to consider a hypothetical cause to a hypothetical problem. Reference is made to FIG. 6, which partially illustrates in greatly enlarged scale, a portion of insert 7 in FIG. 3 . Assuming the designer determines that the cause of an undesired resonance uncovered in testing is that the edge 58 of insert 7 is too high, and that shortening that edge to the height represented by dash line 59 would cure the problem. The designer simply removes cover 9 and unscrews the screws holding insert 7 in place. The insert is then handed over to a machinist with appropriate instructions. Upon return the insert, now with edge 58 , is replaced on the back plate, covered and the unit is retested. In the foregoing procedure, the electronic components remain in place adhering to the back plate. The foregoing procedure may be repeated many times until testing shows satisfactory performance. In the foregoing procedure, should it be determined that too much material was cut away, then all that is necessary to do is to replace the damaged insert with another identical one, and begin trimming anew. Once the exact dimensions of the inserts are determined for proper performance of the electronic circuit, then additional copies may be easily reproduced and used to assemble additional units of the electronic device. Modifications of the foregoing housing become apparent to those skilled in the art. As example, although guide pins are used to position the inserts, as those skilled in the art appreciate, that is a static arrangement. As an improvement, to provide greater flexibility to the package, the guide pins may be mounted, alternatively, to a conventional positioning mechanism, such as a screw and traveler, that is mounted to the underside of the base plate. By moving the positioner mechanism the associated guide pin may be adjusted in position about the base plate's upper surface, and that would change the position of the insert associated with the guide pins. By such means the spacing and relative angular orientation of the inserts may be adjusted. It is believed that the foregoing description of the preferred embodiments of the invention is sufficient in detail to enable one skilled in the art to make and use the invention. However, it is expressly understood that the detail of the elements presented for the foregoing purpose is not intended to limit the scope of the invention, in as much as equivalents to those elements and other modifications thereof, all of which come within the scope of the invention, will become apparent to those skilled in the art upon reading this specification. Thus the invention is to be broadly construed within the full scope of the appended claims.

Development of Millimeter Wave Devices containing MMIC's is expedited by use of a new package for the MMIC's and associated electrical components that define the functional circuit. The package includes a base plate and a plurality of metal inserts removeably fastened to the base plate. The inserts are spaced apart and contain a profiled edge with the profiled edge in one in confronting spaced relationship with that of another of the inserts. Together with the backplate, the profiled edges define elongated cavities, serving as two of the cavities side walls. The cavities serve as a repository for the MMIC devices and some of the additional components and stripline. Should extraneous resonances be discovered, the insert can be removed and adjusted in size and profile, and replaced, thereby adjusting the cavity without disturbing the electronic components or MMIC's which are secured to the back plate. The foregoing eliminates the restrictions imposed by the prior use of mouseholes and avoids the need for rebuilding the entire housing.

This application contains subject matter similar to subject matter disclosed in copending U.S. patent application Ser. No. 09/366,216, filed on Aug. 2, 1999, now U.S. Pat. No. 6,107,167, issued Aug. 22, 2000, and copending U.S. patent application Ser. No. 09/365,411, filed on Aug. 2, 1999. TECHNICAL FIELD The present invention relates to a method of manufacturing a semiconductor device having accurate and uniform polysilicon gates and underlying gate oxides. The present invention is applicable to manufacturing high speed integrated circuits having submicron design features and high conductivity reliable interconnect structures. BACKGROUND ART Current demands for high density and performance associated with ultra large scale integration require design rules of about 0.18 microns and under, increased transistor and circuit speeds and improved reliability. As device scaling plunges into the deep sub-micron ranges, it becomes increasingly difficult to maintain performance and reliability. Devices built on the semiconductor substrate of a wafer must be isolated. Isolation is important in the manufacture of integrated circuits which contain a plethora of devices in a single chip because improper isolation of transistors causes current leakage which, in turn, causes increased power consumption leading to increased noise between devices. In the manufacture of conventional complementary metal oxide semiconductor (CMOS) devices, isolation regions, called field dielectric regions, e.g., field oxide regions, are formed in a semiconductor substrate of silicon dioxide by local oxidation of silicon (LOCOS) or by shallow trench isolation (STI). A conductive gate, such as polysilicon, is also formed on the substrate, with a gate oxide layer in between. A polysilicon layer is deposited on gate oxide. Thereafter, a patterned photoresist mask is formed on the polysilicon layer and the polysilicon layer—oxide layer is etched to form conductive gates with a gate oxide layer in between. Dielectric spacers are formed on sidewalls of the gate, and source/drain regions are formed on either side of the gate by implantation of impurities. Photolithography is conventionally employed to transform complex circuit diagrams into patterns which are defined on the wafer in a succession of exposure and processing steps to form a number of superimposed layers of insulator, conductor and semiconductor materials. Scaling devices to smaller geometries increases the density of bits/chip and also increases circuit speed. The minimum feature size, i.e., the minimum line-width or line-to-line separation that can be printed on the surface, controls the number of circuits that can be placed on the chip and directly impacts circuit speed. Accordingly, the evolution of integrated circuits is closely related to and limited by photolithographic capabilities. An optical photolithographic tool includes an ultraviolet (UV) light source, a photomask and an optical system. A wafer is covered with a photosensitive layer. The mask is flooded with UV light and the mask pattern is imaged onto the resist by the optical system. Photoresists are organic compounds whose solubility changes when exposed to light of a certain wavelength or x-rays. The exposed regions become either more soluble or less soluble in a developer solvent. There are, however, significant problems attendant upon the use of conventional methodology to form conductive gates with gate oxide layers in between on in a semiconductor substrate. For example, when a photoresist is formed on a highly textured surface such as polysilicon, and exposed to monochromatic radiation, undesirable standing waves are produced as a result of interference between the reflected wave and the incoming radiation wave. In particular, standing waves are caused when the light waves propagate through a photoresist layer down to the polysilicon layer, where they are reflected back up through the photoresist. These standing waves cause the light intensity to vary periodically in a direction normal to the photoresist, thereby creating variations in the development rate along the edges of the resist and degrading image resolution. These irregular rejections make it difficult to control critical dimensions (CDs) such as linewidth and spacing of the photoresist and have a corresponding negative impact on the CD control of the conductive gates and gate oxide layers. There are further disadvantages attendant upon the use of conventional methodologies. For example, distortions in the photoresist are further created during passage of reflected light through the highly reflective polysilicon layer which is typically used as a hardmask for etching. Specifically, normal fluctuations in the thickness of the polysilicon layer cause a wide range of varying reflectivity characteristics across the polysilicon layer, further adversely affecting the ability to maintain tight CD control of the photoresist pattern and the resulting conductive gates and gate oxide layers. Highly reflective substrates accentuate the standing wave effects, and thus one approach to addressing the problems associated with the high reflectivity of the silicon nitride layer has been to attempt to suppress such effects through the use of dyes and anti-reflective coatings below the photoresist layer. For example, an anti-reflective coating (ARC),.such as a polymer film, has been formed directly on the polysilicon layer. The ARC serves to absorb most of the radiation that penetrates the photoresist thereby reducing the negative effects stemming from the underlying reflective materials during photoresist patterning. Unfortunately, use of an ARC adds significant drawbacks with respect to process complexity. To utilize an organic or inorganic ARC, the process of manufacturing the semiconductor chip must include a process step for depositing the ARC material, and also a step for prebaking the ARC before spinning the photoresist. There exists a need for a cost effective, simplified processes enabling the formation of an ARC prevent the negative effects stemming from the underlying reflective materials during photoresist patterning. The present invention addresses and solves the problems attendant upon conventional multi-step, time-consuming and complicated processes for manufacturing semiconductor devices utilizing an ARC. DISCLOSURE OF THE INVENTION An advantage of the present invention is an efficient cost-effective method of manufacturing a semiconductor device with accurately formed conductive gates and gate oxide layers. Additional advantages of the present invention will be set forth in the description which follows, and in part, will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from the practice of the present invention. The advantages of the present invention may be realized and obtained as particularly pointed out in the appended claims. According to the present invention, the foregoing and other advantages are achieved in part by a method of manufacturing a semiconductor device, which method comprises: forming an oxide-layer on a semiconductor substrate; forming a polysilicon layer on the oxide layer in a chamber; forming a silicon carbide coating on the polysilicon layer in the chamber; and forming a photoresist mask on the silicon carbide coating. Additional advantages of the present invention will become readily apparent to those skilled in this art from the following detailed description, wherein embodiments of the present invention are described, simply by way of illustration of the best mode contemplated for carrying out the present invention. As will be realized, the present invention is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, all without departing from the present invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive. BRIEF DESCRIPTION OF DRAWINGS FIGS. 1A-1E schematically illustrate sequential phases of a method in accordance with an embodiment of the present invention. DESCRIPTION OF THE INVENTION The present invention addresses and solves problems stemming from conventional methodologies of forming polysilicon gates and underlying gate oxides. Such problems include costly and time-consuming steps limited by materials which require different deposition systems and apparatus. The present invention constitutes an improvement over conventional practices in forming polysilicon gates and underlying gate oxides wherein a photoresist is formed on a highly reflective surface, such as polysilicon. The present invention enables the formation of polysilicon gates and underlying gate oxides with accurately controlled critical dimensions. In accordance with embodiments of the present invention, the semiconductor device can be formed by: forming an oxide layer on a semiconductor substrate; forming a polysilicon layer on the oxide layer in a chamber; forming a silicon carbide coating on the polysilicon layer in the chamber; and forming a photoresist mask on the antireflective coating. Embodiments of the present invention include forming the silicon carbide coating and the polysilicon layer in the same deposition chamber. Interconnect members formed in accordance with embodiments of the present invention can be, but are not limited to, interconnects formed by damascene technology. Given the present disclosure and the objectives of the present invention, the conditions during which the polysilicon layer and the silicon carbide antireflective layer are formed can be optimized in a particular situation. For example, the invention can be practiced by forming the polysilicon layer by introducing a silicon tetrahydride (SiH 4 ) gas in a chamber at a temperature greater than about 600° C., such as about 620° C. to about 650° C. Thereafter, silicon tetrahydride and toluene (C 7 H 8 ) are introduced into the chamber and a layer of silicon carbide is formed on the polysilicon layer in the same chamber. Given the stated objective, one having ordinary skill in the art can easily optimize the pressure, and gas flow as well as other process parameters for a given situation. It has been found suitable to maintain a gas flow of about 250 to about 350 SCCM, such as about 300 SCCM and a pressure of about 100 to about 300 mTorr, such as about 200 mTorr, during deposition of the polysilicon layer. Thus, an effective silicon carbide antireflective coating is formed by an elegantly simplified, cost-effective technique of forming both the polysilicon layer and the silicon carbide layer in the same chamber. An embodiment of the present invention is schematically illustrated in FIGS. 1A-1F. Adverting to FIG. 1A, a wafer 20 comprising a semiconductor substrate 25 , such as silicon, is provided. A barrier layer 30 , comprising an oxide, e.g. silicon dioxide, is deposited on the substrate, as by subjecting the wafer to an oxidizing ambient at elevated temperature. Embodiments of the present invention comprise forming the oxide layer to a thickness of about 100 Å to about 200 Å. With continued reference to FIG. 1A, a polysilicon layer 35 is deposited on the silicon dioxide layer 30 by placing the oxidized substrate in a chamber. The polysilicon layer 35 is formed by introducing a SiH 4 gas in a plasma deposition chamber at 300 SCCM at a pressure of about 200 mTorr and a temperature of about 620° C. Embodiments of the present invention comprise forming the polysilicon layer to a thickness of about 1200 Å to about 1600 Å. With reference to FIG. 1B, a silicon carbide layer 40 is formed on the polysilicon layer 35 , as by introducing SiH 4 and C 7 H 8 . The silicon carbide layer 40 can be formed to a thickness of about 100 Å to about 600 Å. The silicon carbide layer 40 has an extinction coefficient (k) greater than about 0.4, such as about 0.4 to about 0.6, thereby permitting tighter critical dimension control during patterning of the photoresist and tighter critical dimension control of the polysilicon gate and gate oxide, subsequently formed on the substrate 25 . The tighter critical dimension control is possible since the silicon carbide layer 40 absorbs a large percentage of the reflected light and thus prevents a non-uniform distribution of reflected light which may otherwise be incident on the photoresist during photolithography patterning. Referring to FIG. 1C, a photoresist mask 45 is formed on the silicon carbide layer 40 . Photoresist mask 45 can comprise any of a variety of conventional photoresist materials which are suitable to be patterned using photolithography. With continued reference to FIG. 1C, the photoresist mask 45 is patterned and holes 50 are formed in the photoresist mask 45 to provide an opening through which etching of the exposed silicon carbide layer 40 , polysilicon layer 35 and silicon dioxide layer 30 may take place. If critical dimensions, such as a line width and spacing, of the holes 50 in the photoresist mask 45 are not closely controlled, distortions occurring in forming the hole affect the dimensions of the polysilicon gate and gate oxide ultimately formed on the substrate 25 . As mentioned above, such distortions in patterning the photoresist mask 45 occur in conventional methodologies as a result of the high reflectivity of the polysilicon layer 35 and the thickness variations in the polysilicon layer and cause nonuniform photo-reflectivity. The silicon carbide layer 40 of the present invention substantially absorbs light reflected back through the polysilicon layer 35 , thereby reducing incident light on the photoresist mask 45 and preventing fluctuations which would otherwise occur in the critical dimensions of the holes 50 in the photoresist mask 45 . Adverting to FIG. 1D, conventional plasma etching of the silicon carbide layer 40 , the polysilicon layer 35 , and the silicon oxide layer 30 is conducted to strip them from the wafer. The plasma etching may occur in a single step or consecutive plasma etching steps. Referring to FIG. 1E, the photoresist mask 45 and optionally the underlying silicon carbide layer 40 are stripped from the wafer (not shown), utilizing conventional etching techniques. With continued reference to FIG. 1E, a conductive polysilicon gate 35 A remains on substrate 25 with a gate oxide layer 30 A in between. At this point, the wafer continues to the next stage in the overall manufacturing process. Subsequent conventional processing steps, though not illustrated, typically include; forming dielectric spacers on sidewalls of the gate; and forming source/drain regions on either side of the gate by implantation of impurities. In accordance with the present invention, metallization structures are formed in an elegantly simplified, efficient and cost-effective manner. Advantageously, the silicon carbide antireflective layer prevents the formation of standing waves and the negative effects stemming therefrom during photoresist patterning. The silicon carbide antireflective layer formed in accordance with the present invention is particularly advantageous in forming metallization interconnection patterns, particularly in various types of semiconductor devices having sub-micron features and high aspect ratios. In the previous description, numerous specific details are set forth, such as specific materials, structures, chemicals, processes, etc., to provide a better understanding of the present invention. However, the present invention can be practiced without resorting to the details specifically set forth. In other instances, well known processing and materials have not been described in detail in order not to unnecessarily obscure the present invention. Only the preferred embodiment of the present invention and but a few examples of its versatility are shown and described in the present disclosure. It is to be understood that the present invention is capable of use in various other combinations and environments and is capable of changes or modifications within the scope of the inventive concept as expressed herein.

Polysilicon gates are formed with greater accuracy and consistency by depositing a silicon carbide antireflective layer on the polysilicon layer before patterning. Embodiments also include depositing the polysilicon layer and the silicon carbide layer in the same tool.

CROSS-REFERENCE TO RELATED APPLICATION This application claims the priority benefit of Taiwan application serial no. 91119089, filed Aug. 23, 2002. BACKGROUND OF THE INVENTION 1. Field of Invention The present invention relates to a high performance thermally enhanced package. More particularly, the present invention relates to a high performance thermally enhanced package with a cavity type heat sink therein and a method of fabricating the same. 2. Description of Related Art In this information conscious society, multi-media applications are developed at a tremendous pace. To complement this trend, integrated circuit packages inside electronic devices must match a set of corresponding demands for digital input, networking, local area connection and personalized usage. In other words, each electronic device must be highly integrated so that more powerful programs can be executed at a higher speed and yet each package has to occupy less space and cost less. Due to the miniaturization and densification of integrated circuit packages, most packages have an edge length only 1.2 times the encapsulated chip or a package area 1.25 times the chip area. Hence, each package is able to provide powerful functions within a very small area. Furthermore, each chip package can be easily mounted on a printed circuit board using standard surface mount technology (SMT) and common equipment. Therefore, chip packages are mostly welcomed by the industry. The most common types of chip packages include bump chip carrier (BCC) package, quad flat nonleaded (QFN) package and lead frame type package. FIG. 1 is a schematic cross-sectional view of a conventional bump chip carrier package. As shown in FIG. 1 , the bump chip carrier (BCC) package mainly comprises a silicon chip 110 , a layer of adhesive glue 104 , a plurality of bonding wires 106 , a plurality of terminals 108 and a plastic package body 110 . The chip 100 has a plurality of bonding pads 102 on its front surface and contains a layer of adhesive glue 104 on its back surface. The bonding pads 102 on the chip 100 are electrically connected to the terminals 108 through the bonding wires 106 . The plastic package body 110 encapsulates the chip 100 and the bonding wires 106 . In addition, the adhesive glue 104 at the back surface of the chip 100 is exposed outside the plastic body 110 . Through the terminals 108 , the chip 100 can communicate electrically with other electronic devices or a host board. However, to produce this type of package structure, an etching operation is needed to expose the adhesive glue 104 at the back of the chip 100 and shape the terminals 108 . Hence, the structure is a bit complicated to fabricate. FIG. 2 is a schematic cross-sectional view of a conventional quad flat nonleaded package. As shown in FIG. 2 , the quad flat nonleaded (QFN) package mainly comprises a chip 200 , a layer of adhesive glue 204 , a plurality of bonding wires 206 a , a plurality of bonding wires 206 b , a lead frame 208 and a plastic package body 210 . The lead frame 208 has a die pad 208 a and a plurality of leads 208 b . The chip 200 has a plurality of bonding pads 202 on the upper surface. The back surface of the chip 200 is attached to the die pad 208 a through the adhesive glue layer 204 . A portion of the bonding pads 202 on the upper surface of the chip 200 are electrically connected to the leads 208 b through respective bonding wires 206 b . Meanwhile, another portion of the bonding pads 202 on the upper surface of the chip 200 is electrically connected to the die pad 208 b (normally ground pads) through respective bonding wires 206 a . The plastic package body 210 encapsulates the chip 200 , the adhesive glue 204 and the bonding wires 206 a , 206 b such that one side of the die pad 208 a and the leads 208 b are exposed. The exposed surface of the die pad 208 a increases the heat dissipating capacity of the package while the exposed leads 208 b facilitate electrical connection with other devices or a host board. FIG. 3 is a schematic cross-sectional view of a conventional lead frame type of package. As shown in FIG. 3 , the lead frame type package mainly comprises a chip 300 , a layer of adhesive glue 304 , a plurality of bonding wires 306 , a lead frame 308 and a plastic package body 310 . The lead frame 308 has a die pad 308 a and a plurality of leads 308 b . The upper surface of the chip 300 has a plurality of bonding pads 302 thereon. The back surface of the chip 300 is attached to the die pad 308 a through the layer of adhesive glue 304 . The bonding pads 302 on the chip 300 are electrically connected to the leads 308 b through the bonding wires 306 . The plastic package body 310 encapsulates the chip 300 , the adhesive glue 304 , the bonding wires 306 , the die pad 308 a and a portion of the leads 308 b . Thus, the leads 308 b exposed outside the package body 310 can be electrically connected with other carriers. Heat generated by the package is channeled outside through the leads or an externally attached heat sink. Consequently, heat dissipation capacity for this type of package is usually low. All the aforementioned packages have a so-called wire-bonding chip design. In other words, the chip is electrically connected to the package through bonding wires. Bonding wires not only increase overall thickness of a package, but also increase overall circuit path compared with a conventional flip-chip packaging technique. Moreover, to package a wire-bonding chip into a flip-chip package, a wiring redistribution is required. After the redistribution process, overall circuit length will be increased so that a parasitic inductance problem may crop up. SUMMARY OF THE INVENTION Accordingly, one object of the present invention is to provide a thermally enhanced package and a method of fabricating the same that can reduce overall thickness of the package and provide a shorter overall circuit length. To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention provides a thermally enhanced package. The thermally enhanced package mainly comprises a heat sink, a carrier, a layer of adhesive glue, a plurality of first electrical contacts, a silicon chip, a plurality of second electrical contacts and a plastic package body. The heat sink has a cavity. The carrier mounts over the heat sink. Since the heat sink has a cavity, a chip cavity for accommodating the silicon chip is formed between the carrier and the heat sink. The heat sink and the carrier are bonded together through the adhesive glue. The layer of adhesive glue has a plurality of openings that exposes the first electrical contacts. Through the first electrical contacts, the heat sink and a portion of the area on the carrier (such as ground leads and die pad) are electrically connected. The chip is enclosed inside the chip cavity above the carrier. The chip is electrically connected to the carrier through the second electrical contacts. The plastic package body fills up the chip cavity so that the chip and the cavity type carrier form a solid body. In the thermally enhanced package of this invention, the first electrical contacts within the adhesive glue are solder balls, for example. The second electrical contacts for connecting the chip and the carrier electrically are gold bumps or solder bumps. The gold bumps are, for example, the gold stud bumps formed by a wire bond machine or the gold stud bumps formed by electroplating. The carrier inside the thermally enhanced package is a lead frame, for example. The lead frame includes, for example, a die pad and a plurality of leads around the die pad. Each lead can be divided into an inner lead section and an outer lead section. In addition, the die pad and the outer leads are on a different plane (height), thereby providing a space for accommodating a chip. The heat sink of the thermally enhanced package is electrically connected to the die pad on the lead frame and a portion of the leads (such as the ground lead) through the first electrical contacts within the adhesive glue. Hence, the heat sink is actually connected to the ground. In the thermally enhanced package, the gap between the die pad of the lead frame and the active surface of the chip may include a layer of adhesive glue, for example. The carrier inside the thermally enhanced package may be a tape carrier, for example. The tape carrier comprises a tape, a die pad and a plurality of leads surrounding the die pad. The die pad and the leads are laid on the tape. Each lead is divided into an inner lead section and an outer lead section. In addition, the die pad and the outer leads are on a different plane (at different height levels) to produce a space for accommodating a chip. The heat sink of the thermally enhanced package is electrically connected to the die pad on the tape carrier and a portion of the leads (such as the ground leads) through the first electrical contacts within the adhesive glue. Hence, the heat sink is actually connected to the ground. The chip inside the thermally enhanced package may connect to the leads through bonding wires or directly through a flip chip design. Furthermore, adhesive glue may be used to fill the gap between the active surface of the chip and the die pad of the tape carrier. This invention also provides a method of fabricating a thermally enhanced package. First, a heat sink with a cavity thereon is provided. A layer of adhesive glue with a plurality of openings therein is formed over the heat sink. A first electrical contact is formed inside the openings. A carrier is attached to the heat sink through the adhesive glue. The carrier has a cavity that corresponds in position to the cavity on the heat sink so that a space for accommodating a chip is formed. A silicon chip having an active surface is provided. The active surface of the chip has a plurality of bonding pads thereon. A second electrical contact is formed on each bonding pads of the chip. The chip is next positioned inside the chip cavity followed by conducting a thermal compression process so that the chip and the carrier are electrically connected through the second electrical contacts. Finally, plastic material is injected into the chip cavity in a molding process. The carrier inside the thermally enhanced package can be a lead frame or a tape carrier and the chip can be a wire-bonding chip or a flip-chip, for example. The second electrical contacts can be any type of metallic bumps such as gold bumps or solder bumps. The gold bumps can be gold stud bumps formed by a wire bond machine or gold stud bumps formed by electroplating. Before positioning the chip inside the chip cavity in the aforementioned packaging process, adhesive glue may be applied to the active surface of the chip so that the active surface of the chip may connect electrically with the heat sink through the adhesive glue and the carrier. In addition, a dicing process may be conducted to produce individual units after plastic is injected to fill all the chip cavities in an array. It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed. BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings, FIG. 1 is a schematic cross-sectional view of a conventional bump chip carrier package; FIG. 2 is a schematic cross-sectional view of a conventional quad flat nonleaded package FIG. 3 is a schematic cross-sectional view of a conventional lead frame type of package; FIGS. 4A to 4F are schematic cross-sectional views showing the progression of steps for producing a thermally enhanced package according to a first embodiment of this invention; FIG. 5 is a cross-sectional view after the thermally enhanced package in FIG. 4F joins up with a printed circuit board; FIG. 6 is a top view of the lead frame inside the package according to the first embodiment of this invention; FIGS. 7A to 7F are schematic cross-sectional views showing the progression of steps for producing a thermally enhanced package according to a second embodiment of this invention; FIG. 8 is a cross-sectional view after the thermally enhanced package in FIG. 7F joins up with a printed circuit board; and FIGS. 9A to 9C are top views of the tape carrier used in a second embodiment of this invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. FIGS. 4A to 4F are schematic cross-sectional views showing the fabrication steps for producing a thermally enhanced package according to a first embodiment of this invention. As shown in FIG. 4A , a heat sink 400 having a cavity 402 thereon is provided. A layer of adhesive glue 404 is formed over the surface of the cavity 402 . The layer of adhesive glue 404 has a plurality of openings 404 a. As shown in FIG. 4B , first electrical contacts 406 a , 406 b are formed inside the openings 404 a of the adhesive glue layer 404 . The first electrical contacts 406 a , 406 b may protrude slightly above the adhesive glue layer 404 to facilitate subsequent electrical connection with other devices or a host hoard (not shown). As shown in FIG. 4C , a carrier such as a lead frame 500 is provided. The lead frame 500 has a die pad 502 and a plurality of leads 504 surrounding the die pad 502 . Each lead 504 can be further divided into an inner lead section 504 a and an outer lead section 504 b . A portion of the leads 504 in the lead frame 500 are ground leads. These ground leads 504 are electrically connected to the heat sink 400 through the first electrical contact 406 b and the die pad 502 on the lead frame 500 is electrically connected to the heat sink 400 through the first electrical contact 406 a. Since the heat sink 400 has a cavity 402 , a space 506 for accommodating a chip is produced on the lead frame, 500 in a location corresponding to the cavity 402 . The chip cavity 506 has a depth that depends on the type of chip to be enclosed inside the package. As shown in FIG. 4D , a semiconductor chip 408 is provided. The chip 408 can be an ordinary wire-bonding chip or a flip-chip. The chip 408 has an active surface 408 a with a plurality of bonding pads 410 thereon. A second electrical contact 412 is formed over each bonding pad 410 . The second electrical contact 412 are gold bumps or solder bumps, for example. The gold bumps can be, for example, gold stud bumps formed by wire bonding or gold stud bumps formed by electroplating. In addition, a layer of adhesive glue 414 may be applied over the active surface 408 a of the chip 408 . Thereafter, a thermal compression process may be carried out to form electrical connections between the chip 408 and the lead frame 500 . During thermal compression, the chip 408 is electrically connected to the inner leads 504 a of the lead frame 500 through the second electrical contacts 412 . Meanwhile, the active surface 408 a of the chip 408 also connects electrically with the heat sink 400 via the adhesive glue layer 414 , the die pad 502 and the first electrical contact 406 a. As shown in FIG. 4E , an encapsulation process is carried out. In the molding process, packaging plastic 416 is injected to fill the entire chip cavity 506 . Through the packaging plastic, the chip 408 and the lead frame 500 form a solid body. As shown in FIG. 4F , a dicing process may be carried out so that each individual package within an array is separated and excess material surrounding a package is removed. FIG. 5 is a cross-sectional view after the thermally enhanced package in FIG. 4F joins up with a printed circuit board. As shown in FIG. 5 , the package (in FIG. 4F ) mounts on a printed circuit board 700 that serves as its carrier. The printed circuit board 700 is electrically connected to the outer leads 504 b of the lead frame 500 so that the chip 408 forms an assembly with the printed circuit board 700 . In this embodiment, the printed circuit board 700 and the outer leads 504 b of the lead frame 500 are electrically connected through an electrical medium such as third electrical contacts 602 . The third electrical contacts 602 may be fabricated with solder paste, for example. In addition, a heat conductive pad 600 may be inserted in the gap between the printed circuit board 700 and the chip 408 so that heat can be channeled away from the back of the chip 408 via the heat conductive pad 600 to the printed circuit board 700 . FIG. 6 is a top view of the lead frame inside the package according to the first embodiment of this invention. As shown in FIG. 6 , each lead 504 in the lead frame 500 can be divided into an inner lead section 504 a and an outer lead section 504 b . A portion of the junction between the inner leads 504 a a and the die pad 502 may employ a lead break design. The lead break design facilitates the detachment of inner leads 504 a from the die pad 502 . However, the lead break design will be removed in a subsequent operation to prevent the inner leads 504 a and the die pad 502 from short-circuiting. FIGS. 7A to 7F are schematic cross-sectional views showing the fabrication steps for producing a thermally enhanced package according to a second embodiment of this invention. As shown in FIG. 7A , a heat sink 400 having a cavity 402 thereon is provided. A layer of adhesive glue 404 is formed over the surface of the cavity 402 . The layer of adhesive glue 404 has a plurality of openings 404 a. As shown in FIG. 7B , first electrical contacts 406 a , 406 b are formed inside the openings 404 a of the adhesive glue layer 404 . The first electrical contacts 406 a , 406 b may protrude slightly above the adhesive glue layer 404 to facilitate subsequent electrical connection with other devices or a host board (not shown). As shown in FIG. 7C , a carrier such as a tape carrier 800 is provided. The tape carrier comprises a tape 802 , a die pad 804 and a plurality of leads 806 surrounding the die pad 804 . Each lead 806 may be further divided into an inner lead section 806 a and an outer lead section 806 b . A portion of the leads 806 in the tape carrier 800 are ground leads. These ground leads 806 are electrically connected to the heat sink 400 through the first electrical contact 406 b and the die pad 804 on the tape carrier 800 is electrically connected to the heat sink 400 through the first electrical contact 406 a. Since the heat sink 400 has a cavity 402 , a hollow space 808 for accommodating a chip is produced on the tape carrier 800 in a location corresponding to the cavity 402 . The chip cavity 808 has a depth that depends on the type of chip to be enclosed inside the package. As shown in FIG. 7D , a semiconductor chip 408 is provided. The chip 408 can be an ordinary wire-bonding chip or a flip-chip. The chip 408 has an active surface 408 a with a plurality of bonding pads 410 thereon. A second electrical contact 412 is formed over each bonding pad 410 . The second electrical contact 412 are gold bumps or solder bumps, for example. The gold bumps can be, for example, gold stud bumps formed by wire bonding or gold stud bumps formed by electroplating. In addition, a layer of adhesive glue 414 may be applied over the active surface 408 a of the chip 408 . Thereafter, a thermal compression process may be carried out to form electrical connections between the chip 408 and the tape carrier 800 . During thermal compression, the chip 408 is electrically connected to the inner leads 806 a of the tape carrier 800 through the second electrical contacts 412 . Meanwhile, the active surface 408 a of the chip 408 also connects electrically with the heat sink 400 via the adhesive glue layer 414 , the die pad 804 and the first electrical contact 406 a. As shown in FIG. 7E , an encapsulation process is carried out. In the process, packaging plastic 416 is injected to fill the entire chip cavity 808 . Through the packaging plastic, the chip 408 and the tape carrier 800 form a solid body. As shown in FIG. 7F , a dicing process may be carried out so that an individual package within an array is separated and excess material surrounding a package is removed. FIG. 8 is a cross-sectional view after the thermally enhanced package in FIG. 7F joins up with a printed circuit board. As shown in FIG. 8 , the package (in FIG. 4F ) mounts on a printed circuit board 700 that serves as its carrier. The printed circuit board 700 is electrically connected to the outer leads 806 b of the tape carrier 800 so that the chip 408 forms an assembly with the printed circuit board 700 . In this embodiment, the printed circuit board 700 and the outer leads 806 b of the tape carrier 800 are electrically connected through electrical medium such as third electrical contacts 602 . The third electrical contacts 602 may be formed with solder paste, for example. In addition, a heat conductive pad 600 may be inserted in the gap between the printed circuit board 700 and the chip 408 so that heat can be channeled away from the back side of the chip 408 via the heat conductive pad 600 to the printed circuit board 700 . FIGS. 9A to 9C are top views of the tape carrier used in a second embodiment of this invention. As shown in FIGS. 9A , 9 B and 9 C, each lead 806 can be divided into an inner lead section 806 a and an outer lead section 806 b . A portion of the junction between the inner leads 806 a and the die pad 804 may employ a lead break design. The lead break design facilitates the detachment of inner leads 806 a from the die pad 804 . However, the lead break design will be removed in a subsequent operation to prevent the inner leads 806 a and the die pad 804 from short-circuiting. As shown in FIG. 9A , the position of the opening on the tape carrier 800 corresponds to the die pad 804 so that the die pad 804 is directly grounded. In FIGS. 9B and 9C , the die pad 804 and the inner leads 806 a are both supported by the underlying tape 802 . Furthermore, the tape 802 underneath the die pad 804 has a plurality of open holes 810 . Through these open holes 810 , the die pad 804 is also grounded. Moreover, in FIG. 9C , the end of each outer lead 806 b includes a connecting pad 812 . In summary, the thermally enhanced package and associated method of fabrication have at least the following advantages: 1. Using either a lead frame or a tape carrier, overall area and thickness of the package can be reduced. 2. The heat sink in the package is connected to ground through electrical contacts and hence the heat sink can serve as an electromagnetic interference shield. 3. There is no need to use bonding wires to serve as an electrical connection medium. Hence, overall package size can be reduced. 4. The package permits not only the use of flip chips, but also the direct electrical connection between a wiring chip and a lead frame. Since there is no need for redistribution, overall circuit length is reduced and hence problems caused by parasitic induction are minimized. In addition, time for developing and cost for producing a new type of chip is shortened. 5. When flip-chip technique is combined with thermal compression to fabricate the package, yield and reliability of the package is improved. The shortening of average circuit path provides superior linear operation characteristics. 6. Soldering material is not required to join the tape carrier and the chip. Hence, bump pitch can be further reduced to about 45 μm. 7. The tape carrier can be designed into a variety of shapes for accommodating different types of chips. It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.

A high performance thermally enhanced package and method of fabricating the same is provided. A chip (a wire bond chip or a flip chip) and a carrier (lead frame or tape carrier) are bonded together using flip-chip technology and thermal compression. The chip and the carrier are encapsulated using a molding compound. The package has a smaller overall size and the capacity to withstand electromagnetic interference.

CROSS REFERENCE TO RELATED APPLICATION This application claims the benefit of International Application PCT/EP2004/051008, filed Jun. 3, 2004, which claims priority from German Application 103 31 646.9, filed Jul. 12, 2003. BACKGROUND OF THE INVENTION The invention relates to a method for teaching a knowledge-based database for automatic defect classification. In semiconductor manufacturing, wafers or masks are processed sequentially in a number of process steps during the manufacturing process. With increasing integration density, the demands of the quality of the structures formed on the wafers increase. In order to check the quality of the structures formed and to be able to find possible defects, the demand for quality, precision, and reproducibility of the components and process steps used with the wafer is critical. This means that during production of a wafer with a number of process steps, a reliable and early recognition of defects is especially important. In this process, it is necessary to classify the defects that occur in order to thus achieve a fast processing and testing of the wafers. In earlier versions of “Automatic Defect Classification” (ADC), it was necessary to proceed with a manual classification of the defects on a wafer or on a mask. The teaching of a knowledge base was thus extremely time consuming. SUMMARY OF THE INVENTION The object of this invention is to provide a method with which a simple and fast possibility is offered for creating all the data and files (knowledge base, auto alignment, focus setup) necessary for an “ADC run.” This object is achieved by a method of learning a knowledge-based database for automatic defect classification wherein a review data file is selected, and parameters and data are input by a user on one page of a learning mode, where the parameters and the data are known to the user. Additionally, an alignment procedure and a procedure for adjusting light intensity are used. Optimal light intensity is automatically adjusted by approaching a few defects and if necessary regulating the optimal illumination. Detection is checked using a few examples wherein the optimization of the detection parameters is carried out using pictures. Respective defects are detected and a descriptor is assigned to the respective defect by automatically approaching all defects of a wafer or wafers. Descriptors of the defect are then analyzed and automatically grouped. It is especially advantageous that Leica ADC HP offers a simple and fast option for creating data and files (knowledge base, auto alignment, focus setup) for an ADC run. To do this, in part specified data and files are used. Since a manual classification of the defects on a wafer is no longer necessary, as in earlier ADC versions, the time needed to create a new ADC protocol for teaching a knowledge base can be reduced by up to 50%. Additionally, in many cases the quality of the knowledge base improves because of the “pregrouping function” that is included, which in turn has a direct influence on the precision of the ADC run. ADC HP is described as an independent “learn mode”. In individual steps, the user must specify, confirm and if necessary change the required data. The individual steps are shown as separate pages in the Leica ADC HP dialog. The user prompts for the individual pages are in the so-called wizard style, i.e., using <Back> and <Next> buttons. In contrast to the previous learning mode, the new learning mode has the advantage that it is uncomplicated and requires a reduced number of steps that have to be carried out by the user in the proper sequence. In the previous learning mode, preclassified defects were required. All the new learning mode needs is one or more wafers with as many unclassified defects as possible. Since during a few of the steps an interaction with the Viscon interface is necessary, the Leica ADC HP dialog is not displayed modally, but top-most. The dialog can automatically be hidden or the user can make it hidden or visible again. The input of parameters and data includes the selection of the elements present on the semiconductor substrate, whereby it is possible for memory circuits, logic circuits, and a blank wafer without resist or with resist to exist as elements. The parameters or data of the layers on the wafer include the data of a polymer layer, of an oxide layer, of a contact or of a metal layer. The user selects the illumination type, at least one lens and a focus type. For the illumination type, bright field, UV or DUV can be selected. The default setting is bright field, and the default for the lens is 100× magnification. A manual two-point alignment is carried out, whereby a first point is aligned manually by approaching a table. During the learning of the first point, data is automatically stored for the auto alignment file. Each alignment point is learned with three different magnifications of the lens. The adjustment of the optimal intensity of illumination is carried out by random selection of a specific number of defects. Then the selected defects are approached and a picture is taken of each defect. A starting value for the brightness of illumination and the adjustment of the illumination is achieved using a histogram evaluation of the pictures. Defects that are no larger than 25% of the video image width and height are used to adjust the optimal intensity of the illumination. Twenty defects will be used to adjust the intensity of illumination. Of the defects on the wafer that are approached, pictures are taken and stored temporarily until pictures are taken of all defects. After all the pictures have been taken, they are shown on the display as thumbnails. A few thumbnails are rejected if the thumbnails exceed a threshold value for the focus. The analysis and automatic grouping of the descriptors of the defects divides the thumbnails of the defects that have been produced into groups. On the display, the first nine examples of a selected group of defects in a thumbnail representation are shown. BRIEF DESCRIPTION OF THE DRAWINGS In the following, the invention will be explained in more detail using embodiment examples that are shown schematically in the figures. The same reference numbers in the individual figures refer to the same elements. The following are shown in detail: FIG. 1 shows a schematic structure of a wafer inspection device as an overview in which the method according to the invention is implemented; FIG. 2 shows the ADC HP toolbar button with which the user calls the function for automatic defect recognition; FIG. 3 shows the ADC HP call of the “ADC” menu; FIG. 4 shows a “Leica ADC HP Control Desk” window that clearly summarizes, in one window, the ADC tasks that are already partially available in earlier ADC versions; FIG. 5 shows a page of a learning mode that the user calls up and in this process an input file opens, i.e., specifies a review data file; FIG. 6 shows a page of the learning mode that the user calls and thus assigns a name for a “recipe file”; FIG. 7 shows a page of the learning mode by which the user specifies the ADC knowledge base data; FIG. 8 shows a page of the learning mode by which the user carries out the teaching and an automatic alignment; FIG. 9 shows a page of the learning mode by which the user carries out an automatic light adjustment; FIG. 10 shows a page of the learning mode by which the user achieves an optimization of the adjustment of the detection parameters; FIG. 11 shows a representation of the thumbnails on the screen; FIG. 12 shows a representation of a message box; FIG. 13 shows a representation of a change sensitivity dialog; FIG. 14 shows a representation of a window that gives the user a warning message; FIG. 15 shows a representation of an information window for acceptance of the new detection threshold; FIG. 16 shows a page of the learning mode by which the user carries out an automatic generation of a knowledge base; FIG. 17 shows a representation of the “defect code mapping” dialog; FIG. 18 shows a representation of an information dialog; FIG. 19 shows a representation of a dialog for starting the “ADC run”; FIG. 20 shows a representation of a finish dialog; FIG. 21 shows a representation of a report dialog; and FIG. 22 shows a representation of the printed Easy ADC Report. DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a schematic structure of a wafer inspection device 1 as an overview, in which the method according to the invention is implemented. On a base frame 2 , scanning table 4 is integrated as a placement table for wafer 8 . Scanning table 4 can be driven in an X-coordinate direction and a Y-coordinate direction. Wafer 8 to be tested is placed or hooked on scanning table 4 . An observation device that is preferably equipped with a microscope lens 7 is connected to base frame 2 by way of a carrier unit 9 . Microscope lens 7 makes possible the enlarged observation of wafer 8 . Several microscope lenses 7 can be provided on a revolving unit (not shown) so that observation with different enlargements is possible. The structures of wafer 8 that are observed when they are enlarged can be observed directly using eyepiece 5 or by way of a display 11 that is connected to a CCD camera 13 . Additionally, electronic unit 15 is provided with which a system automation can be achieved. In particular, electronic unit 15 is used to control scanning table 14 , for reading out camera 13 and for controlling display 11 . Wafer holder 16 is usually designed in such a way that it can hold wafer 8 to be tested so that it is fixed during the testing period. Scanning table 14 is designed so that it can be driven in each perpendicular X-coordinate direction and one Y-coordinate direction. In this way, each point to be observed on wafer 8 can be brought under optical axis 7 a of microscope lens 7 ( FIG. 1 ). FIG. 2 shows ADC HP toolbar button 20 , with which the user calls the function for automatic defect recognition. The ADC HP dialog is called using “ADC” HP toolbar button 20 or using main toolbar 19 of Viscon application 21 in “ADC” menu or in the context menu of the “ADC” dialog (see FIG. 3 ). Every user (starting from the “operator” user level) has access to this menu entry. Since ADC HP is a separate option, the menu entry is only visible if ADC HP is also installed. This option is protected, as before, using a registry entry that is generated by the installation program when this option is selected. If a program is already loaded in Viscon, the menu entry will be shown deactivated. FIG. 4 shows “Leica ADC HP Control Desk” window 25 . It combines the ADC tasks, some of which were already available in earlier ADC versions, clearly in a window and is used as the starting basis to start individual modules 26 , 27 , 28 , and 29 . In detail, this includes: “Learn recipe”: learning and creation of a new ADC recipe and a knowledge base with subsequent ADC run (run recipe), “Edit recipe”: for processing an available knowledge base, “Expand recipe”: for expanding an available knowledge base and “Run recipe”: to start an ADC run. One button is provided for each of the individual modules. In the current embodiment, this includes “learn recipe”—button 26 , “edit recipe”—button 27 , “expand recipe”—button 28 and “run recipe”—button 29 . When individual buttons 26 , 27 , 28 , 29 are actuated, the individual tasks are executed. Those tasks that were already present in the earlier ADC version will only be discussed briefly here. “Edit recipe”: After pressing is button 27 , the user has to select an available knowledge base file. This is started by the external application “KB Wizard” and the contents of the file are displayed. The data can be processed there and the knowledge base as a whole can be tested. “Expand recipe”: With button 28 , the user selects an available knowledge base file and a review data file. During the subsequent ADC run, new data are collected and temporarily stored in the background. Once the run is completed, the temporary data and the knowledge base (KB) file used will be loaded by the “KB Wizard” application and displayed. The user can now take the new data selectively over into the knowledge base. “Run recipe”: By selection of button 29 , a review data file and an ADC recipe will be selected and an ADC run will be started. All defects selected by the user will be detected automatically and classified using the knowledge base file noted in the ADC recipe. The results will be written again at the end as a review data file. The task connected with the actuation of “learn recipe”—button 26 will be described in detail in the following. The ADC HP learning mode is displayed as a non-modal dialog. The user must input the necessary data and/or select files in eight successive steps, i.e. on eight pages. The last page only represents the result of the ADC HP learning process. To do this, the user can use <Back> and <Next> buttons 30 , 31 (wizard style), as long as the current status allows it, to go to the previous or to the next step (see FIG. 5 ). In general, it is true that the display of the individual pages is not user-level-dependent. The exceptions are additional user interface elements that are only visible to the development user level. These are now visible during the development phase and will be removed in the release version and be generally invisible for all user levels. FIG. 5 shows page 33 of the learning mode that the user calls up and thereby opens an input file 34 , i.e., specifies a review data file. Page 33 is designated with “open input file.” On page 33 , the data file is displayed (without path). Using file open button 35 , the directories are displayed for the user for data input. If an input file has been determined, it is temporarily opened, but the Viscon sequencer is not started. The file “EasyADCLearn.vsl” is used as the script file, hard coded. The necessary data for LotId (lot identification), WaferId (wafer identification), StepId (step identification) and SetupId (setup identification) of the first wafer are read out from the open file. Then the file is closed again. Any standard settings (e.g. Auto Start) are not affected by the process and/or will be put back to the original status. The user can cancel the procedure with a cancel button 39 . FIG. 6 shows page 38 of the learning mode that the user calls up and thereby assigns a name for a recipe file. Page 33 is designated with “recipe file.” Actuating back button 30 is not allowed in page 38 . Actuation of next button 31 is allowed if a valid input file 37 has been selected. The user can cancel the ADC HP learn mode with cancel button 39 . The Leica ADC HP recipe file is displayed in edit box 40 . The previously read name components are summarized according to specification, and the resulting file name (with the extension .“vsl”) is displayed. The name components are separated by a “_” symbol (underscore). Invalid letters in the resulting file name will be removed and hyphens will be replaced with underscores. The user also has the option of changing the specified name (completely or partially) as desired. The file “EasyADCRun.vsl” is used as a template for the resulting recipe file (sequence control file during an ADC run) (hard coded). Page 38 contains several checkboxes 41 , 42 , 43 and 44 . Checkboxes 41 , 42 , 43 and 44 are used to determine the name components. In this case, LotID, StepID and SetupId are used as defaults. The resulting file name (without the extension .“vsl”) is also used as a default for other files (auto alignment, focus setup file, etc.). The data file of the results “result data file” is always written with the same name as the input file and the same format type and in the standard result directory. Back button 30 is permitted and next button 31 is permitted if at least one name component has been selected. Cancel button 39 is permitted. FIG. 7 is shows page 50 of the learning mode by which the user specifies data for the ADC knowledge base. Page 50 is designated as “ADC basic data.” In selection column 51 with the designation “structure type,” the user can choose between “memory” and “logic.” An additional selection or a blank, unstructured wafer “bare wafer” is also possible. To determine the ADC run mode (repetitive or random mode) and/or auto alignment modes (normal auto alignment or bare wafer alignment), the procedure is according to the selection. The default setting is set to “logic.” In selection column 52 , which has designation layer type, the user can select whether one or more layers will be applied to the wafer. Also of interest is which layers will be applied to the wafer. Without resist is “w/o resist,” with resist is “with resist” (see FIG. 7 ). The resists, or also other layers, are applied on wafer 8 or the semiconductor substrate. The default setting is “w/o resist.” In other setting options, the user can select the layer type. A polymer layer is designated with “poly,” an oxide layer with “oxide,” a contact with “contact” or a metal layer with “metal.” The sequence of application of the different layers can also be selected. For example, an oxide layer (oxide) is applied before the polymer layer, this is designated with “before poly.” The selection of the layer type metal allows the user the choice between a single metal layer (metal 1 ), a double metal layer (metal 2 ) and an n-fold metal layer (n-metal). The determination of whether a main layer or a subordinate layer is involved, is used to determine the random mode and the focus type. The default settings for the layers are “poly,” for “oxide”: before poly and for “metal”: metal 1 . Oxide and metal sub-layer radio boxes are only activated if “oxide” or “metal” has previously been selected. Otherwise they are shown deactivated. In selection column 53 , the user can select the “illumination mode.” The radio boxes with the designation BF for bright field, UV for ultraviolet and DUV for deep UV are available to the user. In a list box 54 , the lenses that are available are displayed to the user, whereby only the lenses that fit the selected ADC type are displayed. The default setting is bright field “BF,” and a lens with 100× or lower magnification is suggested. The following table (Table 1) shows the resulting focus setting using the selected data: Layer/ADC type Focus type Offset value for TV focus Poly TV focus 400 Poly resist TV focus 0 Oxide before poly Laser — Oxide before poly resist TV focus 0 Oxide after poly TV focus 2000 Oxide after poly resist TV focus 2000 Contact Laser — Contact resist Laser — Metal 1 TV focus 1500 Metal 1 resist TV focus 0 Metal 2 TV focus 1800 Metal 2 resist TV focus 0 n-Metal TV focus 2500 n-Metal resist TV focus 0 For TV focus, the default values of the “TV Focus Flexible 2 ” mode are used. Back button 30 , next button 31 and cancel button 39 are permitted in this window. If next button 31 is pressed, the ADC HP dialog becomes invisible. A copy of the “EasyADCLearn” files is created and specific actions are adapted (auto alignment) and data (grab setup). The same changes are made for the named copy of the “EasyADCRun” file (the later ADC run recipe). The input file is loaded with the adapted script file, and the Viscon NT sequencer is started. The file is automatically processed up to wafer selection. The standard wafer selection dialog is used and displayed. As a default, all available wafers are selected (default setting in easy ADC script file). FIG. 8 is a page 60 of the learning mode, by which the user carriers out the teaching and an automatic, or at least semi-automatic, alignment, page 60 is designated as “alignment procedure.” After actuation of the wafer selection by the user, the first wafer is loaded and the file is processed up to auto alignment. Depending on the setting of the layers present on the wafer, the learning mode of the corresponding auto alignment will be started (semi-auto or later bare wafer alignment). The user can carry out a manual two-point alignment whereby only the very first point is aligned manually (driving of the table using joystick or by mouse double click in the live video image) and confirmed. During the teaching of the first point, data is automatically stored for the auto alignment file. Each alignment point is taught with three different lens magnifications, whereby the highest magnification lens is specified by the selection on page 50 (ADC basic data). The second point is already taught and aligned automatically using the stored data of the first point. The selected ADC lens is always specified by the software. This lens must be used since it will be needed for the later light adjustment (method used: alignment point). If the learned structure of the first input point is not found on the second alignment point, the second point will be “offset” toward the center point of the wafer and the structure will be searched again. The second point is “offset” by a maximum of six dies before the alignment aborts with a defect. In this case, an information window will be displayed to the user that says that the alignment has been aborted and the wafer is discharged. After the end of the alignment, the Viscon sequencer is paused (incorporated pause action (without message box display) in the easy ADC script file), the ADC HP dialog becomes visible again and displays the next page. Next button 31 is not permitted if alignment is carried out and/or has been aborted due to a defect. Next button 31 is permitted if the alignment was successful. Cancel button 39 is permitted and cancels the entire ADC HP learning mode. FIG. 9 is page 70 of the learning mode by which the user carries out an automatic light adjustment. This page is designated as “light adjustment.” After pressing a “perform automatic light adjustment” button 71 , a specific number of points (defects from the data file) will be selected randomly. If size information is available, only defects will be selected that are greater than 25% of the video image width and height. These defects are approached and pictures are taken. A “lamp brightness” start value is determined using histogram evaluation and adjusted at the microscope. This means that the brightness will be regulated down so that no defect image is “overwritten.” To do this, all available color channels will be tested and adjusted in an appropriate way. Then an automatic light adjustment is carried out. If it is successful, the data obtained will be stored in the knowledge base file. As a default, 20 points (defects) are used for the “starting value” determination and the “alignment” method of the light adjustment is used. Page 70 contains Statusbox 72 (“progress control box”) and Infobox 73 “read only edit box.” During the automatic light adjustment, the progress is displayed in Statusbox 72 . A status text is displayed in Infobox 73 whether this is successful or unsuccessful. Back button 30 is not permitted when the light adjustment is being carried out. Back button 30 is permitted if the light adjustment is rejected. The wafer is discharged, and page 50 “ADC basic data” is displayed. Next button 31 is permitted if the light adjustment was successful. The cancel button is permitted if light adjustment has been carried out and in this process all open files were closed and deleted. FIG. 10 is a page 80 of the learning mode, by which the user achieves an optimization of the setting of the detection parameters. Page 80 is designated as “optimize ADC detection.” The process is started using a button 81 , which is designated as “start optimization.” The optimization function will ensure that the standard values for focus adjustment and detection parameters function on the selected wafer. If this is not the case, the user has the option here again of changing the specified standard values. After button 81 is pressed, the Viscon sequencer is started, defects are selected, approached and pictures are taken. The text on button 81 then changes into “stop optimization.” The progress of the picture taking is displayed in a status box 82 . The user can then cancel the procedure by pressing it again. If all the necessary pictures have been taken, they will be displayed in another dialog in an additional representation on the screen as thumbnails. Ten defects (hard coded) are used for optimization. The number can be changed using a registry entry and/or development user level. Back button 30 is not permitted if the detection optimization is being carried out. Next button 31 is not permitted if the detection optimization is carried out. Cancel button 39 is not permitted if the detection optimization is carried out. By pressing <Start Optimization> button 81 , the Viscon sequencer is started again, the button text changes to “stop optimization” and a specified number of defects of the current wafer is selected. The defects are approached and in this process a special ADC action is initiated. This action takes the pictures, detects the defects using an ADC routine that is already developed and stores the pictures temporarily until pictures of all the defects have been taken. The progress of this procedure is displayed by means of the status box. During picture taking, the user can cancel the procedure by repeatedly pressing the button. FIG. 11 shows a representation of several thumbnails 91 1 , 91 2 , 91 3 , . . . , 91 n on display 11 . If all pictures have been taken, the ADC HP dialog is switched to invisible and the pictures are displayed in a thumbnail dialog 90 (complete picture display on the screen). The Viscon sequencer pauses at this time. Thumbnail dialog 90 is basically divided into first area 91 , second area 92 , third area 93 and a fourth area 94 . First area 91 comprises a horizontal list in which thumbnails 91 1 , 91 2 , 91 3 , . . . , 91 n are represented with detection marking and defect ID (defect identification). The currently selected picture is shown in second area 92 with a maximum resolution of 640×480 pixels. If available, the reference pictures are also shown, reduced, in third area 93 . The current picture selection can be changed using a mouse click, cursor keys and/or browse buttons 95 under the defect picture. The defect marking can be switched off and back on again using <Hide Defect Detection> button 96 . Browse buttons 95 are used for selection and display of the next or the previous defect picture. <Hide Defect Detection> button 96 is designed as a toggle button, and in this way the detection marking can be made visible or invisible. Focus difference—defect/reference button 97 makes it possible to display a message box 86 (see FIG. 12 ). During operation, the selected defect picture (and available reference pictures) will be thrown away, i.e., deleted from the display. If an internal threshold value (default: 30%) of the unsatisfactory pictures thrown away (bad focus pictures) is exceeded, the focus values are changed (i.e., change from laser to TV focus or change of the TV focus offset in 500 nm steps). The defects are then approached again and data recorded. To do this, thumbnail dialog 90 is closed and the ADC HP dialog will be displayed again during the scan procedure. Wrong defect detection button 86 makes it possible for the detection threshold for the selected picture to be determined again. To do this, a new dialog 80 is displayed (see FIG. 10 ). Refresh button 87 makes it possible for the average value of the threshold of all pictures in the list to be determined, and all detections will be recalculated with this new average value. The list will then be set up again. Pictures with “autothreshold” (−1) are not used to determine the average value. Default button 88 makes it possible for all the changes in the detection parameters of all pictures to be reversed. The list is set up again with the original values. The dialog is closed with an apply button 89 , the average value of the threshold is calculated and taken over as a global detection parameter. Pictures with “autothreshold” (−1) are not included for determining the average value. The optimized dialog is closed, the ADC HP dialog is switched so that it is visible again and the new overall detection threshold is entered in the knowledge base. Cancel button 39 closes the optimize dialog, and the ADC HP dialog becomes visible again. All changes are rejected. FIG. 13 is an illustration of a dialog 100 for “change sensitivity.” Dialog 100 is used to determine the optimum setting for the detection threshold of the selected defect picture. Defect picture 101 is displayed centrally with the associated detection threshold in dialog 100 . If indirect automatic detection threshold has been used due to prior adjustments (on page 50 “ADC Basic Data”), a value of 50% is assumed. The sensitivity of the detection can be reduced or increased using two buttons 102 . Defect picture 101 shown in the center shows the defect recognition with the currently selected sensitivity. The value is shown under defect picture 101 . Reduced picture 103 is shown on the left next to defect picture 101 and shows the change in detection with reduced sensitivity. Also, reduced picture 103 is shown at the right next to defect picture 101 and shows the change of the detection with increased sensitivity. By clicking with the mouse on one of the reduced pictures and/or by pressing on the buttons 102 lying under them, the current sensitivity is changed to this value and the picture is now shown in the center. The changes on the left and right will then be recalculated. Hide defect detection button 105 is designed as a toggle button. In this way, the detection marking is switched to visible or invisible. Slider 106 with the designation “sensitivity step size” is used to change the magnitude of changes of sensitivity during actuation of button 102 . Delete image button 107 is used to reject a defect for further evaluation. The defect is removed from the list of the optimization dialog. This dialog is closed, and the user goes to the previous dialog. FIG. 14 is a representation of a window 110 that gives the user a warning message. If an internal threshold (default: 30%) of the “wrong detection” pictures rejected is exceeded, new defects can be selected (automatically), approached and data recorded. Apply button 107 starts the application. FIG. 15 is a representation of information window 110 for acceptance of the new detection threshold. The information window informs the user that by acceptance of the new detection threshold the detection of all the other pictures will also change. The new value will be applied to all other pictures by pressing on <Refresh> button 87 in optimize dialog 90 . By operating <Yes> button 111 , the detection threshold of the center image display is taken over and the user goes back to dialog 100 . By operating cancel button 39 change in dialog 100 , all changes made are rejected and the user goes back to optimization dialog 90 (see FIG. 11 ). FIG. 16 shows page 120 of the learning mode, by which the user carries out an automatic generation of a knowledge base. With start collecting data button 121 , all the necessary data for all defects of all selected wafers are accepted and recorded. The status is displayed to the user in Statusbox 122 and Infobox 123 . Infobox 123 displays the defects “yet to be processed” from the total number (e.g. “267 of 750”). Operating back button 30 is not allowed when the data acceptance procedure is running. Operating next button 31 is also not allowed if the data recording procedure is running. Operation of cancel button 39 is not allowed when the data recording procedure is running. If the actuation of cancel button 39 is allowed, all open files will be closed and deleted. The sequence is as follows: The Viscon sequencer is started again and all defects of the input file are selected. In a first step, defects on the wafer or wafers are approached, pictures are taken, descriptors generated and stored in the ADC result data on the defect. The pictures of the defects will be stored with the following settings: “Write to Archive File” “All Images” “Image Compression”: yes “Leica-ImageStore”: no In a second step, the Viscon sequencer pauses on the basket level (before storing the output file). In a third step, the generation of the groups from the collection of descriptors occurs (“pregrouping”). In a fourth step, the pregrouping attempts to create a maximum of 20 groups. Groups with less than two examples are rejected. The resulting groups are copied temporarily to the knowledge base, whereby the defect code and defect description of each group are “numbered” for the first time (1, 2, 3, etc., or EasyClass 1 , EasyClass 2 , EasyClass 3 , etc.) In a fifth step, dialog 130 is displayed for dividing the defects i.e. “defect code mapping” (see FIG. 17 ). “Defect code mapping dialog” 130 is essentially represented by first window 131 , a second window 132 , third window 133 and a fourth window 134 . In first window 131 , a binder icon is shown for each group generated in the fourth step. Window 132 displays the pictures of the first nine examples of the selected group in a thumbnail representation. Window 133 displays the actual defect code table. By selecting a defect code and pressing <Map> button 135 , this code is assigned to the selected classes. The icon of this class changes in that it gets a green hook 136 and the corresponding defect code text is displayed. This “mapping” can also be executed by a double click in the defect code table. When <Delete Group> button 137 is pressed, the currently displayed group is marked for deletion. The corresponding binder icon gets a red cross 138 . When pressed, toggle button 139 designated with “optimize image display” makes it possible for a section around the defect marking in original size of the example pictures to be shown. If the defect marking in an example picture is too large, the display does not change. By pressing toggle button 139 on again, you go to the reduced full picture display. Operation of apply button 129 is allowed if all defect groups have been handled, i.e., mapped or marked for deletion. In a sixth step, there is an attempt to reduce the number of individual examples per mapped group (groups marked as for deletion will not be used and rejected). This is necessary so that specific groups with a lot of defects do not dominate the knowledge base and defects can preferably be assigned to this class. The result is taken over into the knowledge base, and the user comes to the ADC learning mode during operation of cancel button 39 on display 11 of information dialog 140 shown in FIG. 18 . After operating <Yes> button 141 , the “mapping” in the entire ADC learning mode will be canceled. FIG. 19 shows a representation of a dialog 150 for starting an ADC run. With a start ADC run button 151 , after button 151 is pressed there is a classification of all defects of the selected wafers “offline” (i.e., without approaching them again). The classification is carried out with the current ADC knowledge base. Dialog 150 includes a Statusbox 152 and Infobox 153 . The display of the defects yet to be classified of the total number is displayed in Statusbox 153 (e.g., “123 of 750”). Operation of back button 30 is not permitted if Offline ADC is running. Operation of next button 31 is not permitted if Offline ADC is running. Also the operation of cancel button 39 is not allowed if Offline ADC is running. If the operation of cancel button 39 is allowed, all open files will be closed and deleted. If next button 31 was pressed, the sequencer is started again. The result data file is written and the sequencer ends automatically, whereby all files that are still open are closed. FIG. 20 shows a representation of a dialog 160 which is the finish screen. An Infobox 161 is provided for an output file. Infobox 161 is used to display the stored data files. Only the file name is displayed. The Easy ADC VSL file is also displayed in Read Only Editbox 162 . The display of the generated “ADC run” file appears in Infobox 162 . Only the file name is displayed. The complete path is displayed in a tool tip. The number of “total defects” is displayed in Infobox 163 . The total number of all defects can be read Infobox 163 . The “defects detected” will be displayed in Infobox 164 . The “redetection” of the defects in percent will also be displayed in Infobox 166 . The display of the defects detected with ADC is shown absolutely and as a percentage. LED 149 displays in color whether the percentage lies above the predefined value. If the value lies above the predefined value, LED 149 is green, otherwise LED 149 is red. The number of classified defects is displayed in Read Infobox 165 . The percentage of classified defects “classifiability” is also shown in Infobox 167 . The display of the defects classified with ADC is shown absolutely and as a percentage. LED 148 shows in color whether the percentage lies over a predefined value. Green means that the percentage lies over the predefined value. If the value lies below that, the display is red. By operating a report button 147 , a report dialog 170 is displayed ( FIG. 21 ). Report dialog 170 is user-dependent. Another report is displayed only starting at the ‘engineer’ user level. The operation of finish button 146 will end the process. FIG. 21 shows report dialog 170 with the expanded display of data in an Infobox 171 . The following data are output: file information: (P) output file name (+path), recipe information: (P), ADC HP recipe file name (+path), knowledge base file name (+path), auto alignment file name (+path), focus type “LASER” or “VIDEO” with grab setup file names (+path), knowledge base information (A) (P), lens used, contrast method used, focus type, aperture used, light intensity used, statistical information (P), number of wafers, total number of defects, number of classified defects, number of ADC classes, defects per class (in matrix form), number of detected defects, absolute/percent, number of classified defects, absolute/percent, number of classifications per ADC defect class (P), performance information: (A) (P), accuracy, purity, confusion matrix (A) (P) and a defect list (A). A sorted table contains the following data per date record: the slot number, the event number, the manual classification, the ADC classification, the ADC classification with confidence value and the ADC classification with confidence value. In this case, only the first 300 entries are output. (A) means that these data are visible only in the expanded report. (P) means that the data can be printed out. Report dialog 170 is provided with print button 171 . A preview of the ADC HP report is displayed on display 11 . The printout can be printed out using a standard printer. The printout is in landscape format since in portrait format the paths are usually not completely displayed or printed out. FIG. 22 is a representation of a printed Easy ADC Report 180 . When save button 173 is operated (see FIG. 21 ), the ADC HP report can be stored as a test file (extension TXT).

The invention relates to a method of learning a knowledge-based database used in automatic defect classification. According to this method, the user is spared a series of entries as the system carries out an automatic learn mode, which requires a reduced number of user entries.

[0001] This application is a national phase application of PCT/KR2006/002872, and claims priority from Korean application (KR) 20-2005-0022608 (Aug. 2, 2005) for inventor KIM, Ki Ryong. TECHNICAL FIELD [0002] The present invention relates to a road traffic-control signboard assembly, and more particularly, to a road traffic-control signboard assembly having an automatic returns function. BACKGROUND ART [0003] Road traffic-control signboards are essential elements in running of vehicles. Since road traffic-control signboards should be optimally recognized at drivers' visual fields, they are usually fixed at right angle to vertical supports which are built vertically at the margin of roads. For example, a conventional road traffic-control signboard assembly will be described below with reference to part of FIG. 1 . [0004] In the case of the conventional road traffic-control signboard assembly, a road traffic-control signboard 40 is simply fixed to the road traffic-control signboard stay bar 1 which is extended again over the road, using a U-bolt and nut. Therefore, assemblers' manpower can be reduced but the durability thereof is very poor. The following problems are caused. That is, as stated above, the conventional road traffic-control signboard assembly assembles the road traffic-control signboard 40 with the traffic signboard stay bar 1 using the U-bolt and nut. Thus, if strong force is applied to the conventional road traffic-control signboard assembly, because typhoon blows, an initial position of the road traffic-control signboard 40 is changed to thus make the front surface of the road traffic-control signboard 40 turn up to the sky or down to the road, or make it suspended at a slope. As a result, the road traffic-control signboard 40 loses its function and causes a failure in safety running of vehicles. [0005] In the meantime, if impact is applied to the conventional road traffic-control signboard assembly, due to the excessively loaded freight in freight vehicles or the top portion of special-purpose motor vehicles such as cranes or heavy equipment, the obverse of the road traffic-control signboard 40 is slanted heading toward the road or is damaged. Finally, the same problems as those described above are caused. Hereupon, local government road facilities that receive accident or damage reports ride bucket vehicles and go to sites immediately, in order to straighten the road traffic-control signboard whose initial position has been changed again or replace it by a new one. For this reason, roads are blocked to thus delay a smooth road condition and cause a big economical loss and damage nationalistically. On the other hand, when typhoon blows or after typhoon passes a lot of road traffic-control signboards are out of position over the downtown whole area. In this case, big problems such as confusion, discomfort, and traffic jams are caused. [0006] Moreover, repair works of long hours cause various kinds of big problems. Hereupon, to solve the above-described problems, this inventor filed a Utility-model application No. 20-2003-0040773 on Dec. 26, 2003 with the Korean Intellectual Property Office entitled “Horizontal support structure for making traffic-control signboards rotate” which has been registered as a Utility-model registration No. 20-0349900-0000 on Apr. 29, 2004. By the way, the above-described registered conventional art greatly changes the structure of the existing road traffic-control signboard stay bar 1 . In principle, the existing road traffic-control signboard stay bar 1 does not cause any problem but is complicated in the structural viewpoint since a coil spring should be is mounted so as to be concentric with the road traffic-control signboard stay bar 1 . As a result, in the case of the conventional art, it is not so easy to manufacture the road traffic-control signboard 40 and assemble it in the road traffic-control signboard stay bar 1 to thus cause the manufacturing cost to greatly rise up and the maintenance to be difficult and to additionally cause an unsafe problem since the weight of the road traffic-control signboard assembly is heavy. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT [0007] To solve the above problems, it is an object of the present invention to provide a road traffic-control signboard assembly having a generally advanced automatic return function using structure of an existing road traffic-control signboard stay bar 1 as it is, which is preeminently improved in view of the function, economy, assembly, maintenance, weight, etc., in comparison with those of the conventional art. To accomplish the above object of the present invention, according to an aspect of the present invention, there is provided a road traffic-control signboard assembly comprising: a tubular elastic body having an insertion groove so as to be inserted into a road traffic-control signboard stay bar which is connected with a vertical support at right angle and a hole into which a rotation preventing screw can be inserted at right angle; a semicircular upper clamp which is assembled to enclose the tubular elastic body at the upper portion of the tubular elastic body, including a tightener having bolt holes through which a respective bolt is penetratively fixed for fixing a below-described lower clamp, in which the tightener is extended from the semicircular upper clamp, a hole into which a rotation preventive screw can be inserted at right angle, and a hasp which can hang a below-described tension spring on the upper portion of the semicircular upper clamp; a flat lower clamp which is hinged with the upper clamp, having bolt holes through which a respective bolt is penetratively fixed for fixing the upper clamp; a support plate which is assembled in a hinged manner with the lower clamp and the upper clamp, to support a road traffic-control signboard; a hinge pin which assembles the upper clamp, the lower clamp and the support plate all in a hinged manner; a reinforcement plate at the upper portion which a hanger for hanging the tension spring, in front of which the road traffic-control signboard is fixed, and with which the support plate is assembled with bolts and nuts; a tension spring which is assembled between the hasp of the upper clamp and the hanger of the reinforcement plate, which supports the road traffic-control signboard so as to return vertically even if the road traffic-control signboard moves; and bolts and nuts which rigidly tighten the upper clamp and the lower clamp. Preferably, a plate-shaped or rod-shaped stopper is additionally fixed on the upper portion of the upper clamp, so that the erect road traffic-control signboard is not inclined toward the upper clamp Preferably, the material of the tubular elastic body is selected among rubber, sponge, and urethane. BRIEF DESCRIPTION OF THE DRAWINGS [0008] The above and other objects and advantages of the present invention will become more apparent by describing the preferred embodiments thereof in detail with reference to the accompanying drawings in which: [0009] FIG. 1 is a perspective view showing the whole structure of a road traffic-control signboard assembly according to the present invention; and [0010] FIG. 2 is a sectional view showing a-state of use of the road traffic-control signboard assembly according to the present invention. BEST MODE FOR CARRYING OUT THE INVENTION [0011] Herein below, a road traffic-control signboard assembly according to a preferred embodiment of the present invention will be described. The same reference numeral presented in the drawings show the same element. [0012] First, the road traffic-control signboard assembly according to the present invention does not change structure of an existing road traffic-control signboard stay bar 1 but uses it as it is. In this point of view, the present invention differs greatly from the conventional art. The present invention has many inventive characteristics in which its structure is very simpler and its durability is more excellent than those of the conventional art. [0013] That is, referring to FIGS. 1 and 2 in the present invention, a tubular elastic body 30 made of rubber, sponge, or urethane can be simply inserted into a proper position of a road traffic-control signboard stay bar 1 (hereinafter, referred to as a stay bar 1 ). As shown in FIGS. 1 and 2 , an insertion groove 31 that can be inserted into the outer surface of the stay bar 1 . The lower portion of the tubular elastic body 30 is opened and thus the insertion groove 31 can be extended by hands seizing the tubular elastic body 30 . Then, the tubular elastic body 30 can be simply inserted into the stay bar 1 . Finally, the tubular elastic body 30 is closely fixed to the stay bar 1 as shown in FIG. 2 . In the meantime, the tubular elastic body 30 is preferably fabricated in various forms in size, according to change in diameter of the stay bar 1 , but since the tubular elastic body 30 has an elasticity naturally, there is no reason to produce the tubular elastic body 30 in various sizes certainly because there is no problem to use it even if diameter of the stay bar 1 is a little big or small. Further, since the standard and diameter of the stay bar 1 are substantially the same, only one basic type of the tubular elastic body 30 can be used without causing any problems. [0014] As described above, after the tubular elastic body 30 is inserted into the stay bar 1 , a hole is formed on the stay bar 11 through a hole 32 using a hand drill. The diameter of the hole does not cause any hindrance in intensity of the stay bar 1 . In this case, if the end portion of a rotation preventive screw 16 may be inserted into the hole, the diameter of the hole can be acceptable. Here, the tubular elastic body 30 can be assembled with the stay bar 1 after a hole has been formed on the stay bar 1 . [0015] Next, after a semicircle upper clamp 10 is positioned at the upper portion of the tubular elastic body 30 , the rotation preventive screw 16 is assembled through the hole 32 of the tubular elastic body 30 and a hole 13 of the upper clamp 10 . Accordingly, as shown in FIG. 2 , the tubular elastic body 30 and the upper clamp 10 can be kept in their positions on the stay bar 1 . [0016] Then, a flat lower clamp 20 which is assembled with the upper clamp 10 by a hinge pin 15 in a hinged manner, is made to contact the bottom of the stay bar 1 and to be fixed to the stay bar 1 using bolts 50 and nuts 51 , as shown in FIG. 2 . [0017] Then, a support plate 70 is assembled in a hinged way with the upper clamp 10 and the lower clamp 20 by the hinge pin 15 . Then, a reinforcement plate 60 to which a road traffic-control signboard 40 is fixed, is located in front of the support plate 60 , and is assembled by bolts 41 and nuts 42 . That is, the support plate 70 , the reinforcement plate 60 and the road traffic-control signboard 40 are integrally formed. [0018] As shown in FIGS. 1 and 2 , a tension spring 80 is hung between a hasp 14 of the upper clamp 10 and a hanger 61 of the reinforcement plate 60 , and assembled. As shown in FIG. 2 , a plate-shaped or rod-shaped stopper 90 is additionally fixed on the upper portion of the upper clamp 10 , so that the erect road traffic-control signboard 40 is not inclined toward the upper clamp 10 . [0019] As described above, the rotation preventive screw 16 can be replaced by an ordinary pin, bolt, or annular rod. Here, when the tubular elastic body 30 and the upper clamp 10 are assembled with the stay bar 1 after the annular rod is soldered and fixed to the stay bar 1 beforehand, the annular rod can pass through and protrude from the respective holes 32 and 13 . However, in this case, it is naturally expected that it will be difficult to work. Also, the tubular elastic body 30 of the present invention is cut at its lower portion thereof, and thus the insertion groove 31 is opened. Accordingly, the lower clamp 20 contacts justly the bottom of the stay bar 1 , and thus the road traffic-control signboard 40 can be turned by as a big angle as an arrow trajectory of FIG. 2 . As a result, in the case that impact due to collision of a freight vehicle is applied to the lower portion of the road traffic-control signboard 40 , the road traffic-control signboard 40 is smoothly escaped from the impact lest the central portion of the road traffic-control signboard 40 should not be damaged. As being the case, a perfectly pipe-shaped tubular elastic body can be used. In the meantime, as described above, any commercial changes belong to the technical scope of the present invention. [0020] It is natural that two sets of road traffic-control signboard assemblies according to the present invention be used for one road traffic-control signboard. If the road traffic-control signboard becomes large in size, it is natural that several road traffic-control signboard assemblies be assembled with one stay bar in use. [0021] As described above, the road traffic-control signboard assembly according to the present invention is used in the state of FIG. 2 . Even if wind force or other impact is applied in front of the road traffic-control signboard 40 in the FIG. 2 state, the road traffic-control signboard 40 is pushed to the left-side direction of the arrow and is turned over within various angle ranges. Thereafter, if the wind force that is, birr or other impact disappeared, the road traffic-control signboard 40 returns to the original position by the pulling force of the tension spring 80 . Here, a reason why the road traffic-control signboard 40 has been pushed backward by the birr or impact which has been applied to the road traffic-control signboard 40 is because the stopper 90 is fixed to the upper clamp 10 , and thus the upper portion of the road traffic-control signboard 40 is not pushed backward based on the hinge pin 15 . [0022] In the meantime, even in the case that strong wind blows from the left side of the road traffic-control signboard 40 to the right side thereof, in the FIG. 2 state, the road traffic-control signboard 40 is not turned to the left side of the road traffic-control signboard 40 but is turned only to the right side thereof. This is also because the road traffic-control signboard 40 cannot be turned toward the upper clamp 10 by the stopper 90 . Here, a coil spring is assembled with the hinge pin 1 , to thus keep the road traffic-control signboard 40 in its position. However, it is not always necessary to assemble the coil spring with the hinge pin 1 . [0023] As described above, the present invention provides a road traffic-control signboard assembly having an automatic return function even if impact is applied to a road traffic-control signboard. The conventional art changes the structure of the stay bar 1 , but the present invention does not change the existing stay bar 1 in use. This feature of using the existing stay bar without changing the structure of the stay bar is inventive in itself. Further, the road traffic-control signboard assembly can be simply assembled with and disassembled from the stay bar 1 , and the structure of the road traffic-control signboard assembly is very simple. Accordingly, it is easy to fabricate the road traffic-control signboard assembly. Moreover, the present invention is more excellent in its maintenance, more inexpensive in its manufacturing unit cost, and lighter in its weight to thus enable a very easy installation and maintenance work, than those of the conventional art. As a result, the present invention has an economic efficiency having preeminently improved characteristics. [0024] Further, a semi-permanent use is possible since the present invention has an excellent durability from the structural characteristic and the frequent breakdown has hardly occurred. In particular, the tubular elastic body 30 does not need to be fabricated according to diameter of the stay bar 1 , even if the diameter of the stay bar 1 alters a little, and the road traffic-control signboard assembly according to the present invention can be flexibly used, to thereby provide an effect of doing a big contribution in enhancing the whole economic efficiency, convenience, workability. [0025] As described above, the present invention has been described with respect to particularly preferred embodiments. However, the present invention is not limited to the above embodiments, and it is possible for one who has an ordinary skill in the art to make various modifications and variations, without departing off the spirit of the present invention. Thus, the protective scope of the present invention is not defined within the detailed description thereof but is defined by the claims to be described later and the technical spirit of the present invention. INDUSTRIAL APPLICABILITY [0026] As described above, the present invention provides a road traffic-control signboard assembly which can be used for a traffic-control signboard.

Provided is a road traffic-control signboard assembly with which a road traffic-control signboard can be assembled while being linked with a vertical support at right angle. The road traffic-control signboard assembly is fitted with and fixed to a road traffic-control signboard stay bar and has a structure of being returned to an original position even if impact by typhoon or collision of vehicles is applied to the road traffic-control signboard. Thus, the road traffic-control signboard assembly prevents a phenomenon that an initial fixed position of the road traffic-control signboard is changed because of impact by typhoon or collision of vehicles which is applied to the road traffic-control signboard, to thereby lose the function of the road traffic-control signboard.

BACKGROUND OF THE INVENTION The present invention pertains to an apparatus for threading metal into a heating device and for removing scales that form and flake from the metal during heating. More particularly, the present invention relates to an induction heater having a continuous belt that threads metal strip into the induction heater and removes metal scales that form and flake from the metal during heating. Induction heating is used to heat metal pieces such as, strip, bars, slugs, billets, tubes, slabs, plate and the like, by passing the metal pieces through a pathway wherein the metal is heated by an induction coil. The purpose of the induction heating may be to permit hot rolling, annealing, hardening, brazing or soldering two parts together, or treating metal in some other manner. One particular application of induction heaters involves their use in conjunction with the continuous casting of metal strip. Because metal strip is thin and wide having a large surface area, it cools quickly upon exiting a continuous caster. Therefore, an induction heater, such as a transverse flux coil, may be utilized to reheat the strip metal so that it can be properly rolled. A transverse flux coil is desirable because of its ability to operate in a relatively small space, and heat thin metal strip in the above Curie temperature range. When induction heaters are utilized in conjunction with continuous casters, at least one problem arises. After the metal strip exits a continuous caster, it is soft and limp because it is hot. As a result, it is difficult to thread the metal strip horizontally through an induction heater such as a transverse flux coil. To date, there is no device that the applicant is aware of that effectively threads limp or soft metal through an induction heater. Thus, a need exists to provide such an apparatus. An additional problem associated with induction heaters when used in any application involves the formation of metal scales during heating. All heating of metals causes at least some scale to form on the surfaces of the part undergoing treatment when the heating processes are carried out in an oxygen-containing environment such as air. Ambient air, containing oxygen reacts with the metal at elevated temperatures causing scales to form on the surface of the work-piece. As the induction heater continues to increase the temperature of the metal, the scales flake off or fall from the work-piece. The flaking off of scales into the induction heating device is an undesirable result since it often causes failure of the induction coils. One of the most prevalent causes of failure resulting from flaking of metal scales involves short circuiting. The metal scales drop from the work-piece and accumulate between the work-piece and the inductor. As the scale builds up within the housing of the induction heater, they begin to span the space between the work-piece and the inductor. Thus, a complete circuit is formed therebetween. Since the work-piece is generally supported by metal support components of the induction heating apparatus which are grounded, a short circuit is completed to ground through the inductor and work-piece. In an effort to alleviate some of the adverse effects accompanying a short circuit of the foregoing character, prior designs have provided a sensor for detecting a short circuit before significant damage is done. For example, in response to detection of a short circuit, a control circuit may be actuated to disconnect the inductor from its power supply. This causes the inductor to de-energize so that the necessary steps can be taken to remedy the short circuit condition. In addition, a control circuit may be rendered operable to preclude the work-piece from entering the induction heater. While short circuit detection devices of the foregoing character advantageously serve to protect the inductor and/or work-piece from significant damage, a considerable amount of production time is lost in shutting down the apparatus and performing the necessary maintenance operations to clear the inductor area of the metal scales causing the short. Furthermore, once the inductor area is cleaned, it is only a matter of time before scale accumulation will again cause a short to ground requiring shut-down and additional maintenance. Another attempt to solve the problems associated with the formation of scales during induction heating is disclosed in U.S. Pat. No. 3,745,293 (Seyfried). Seyfried teaches an induction heating apparatus having an auxiliary circuit operable to cause burning of metal scales disposed between the inductor and work-piece. Such burning is achieved by establishing a low voltage circuit through the inductor and work-piece and the metal scales therebetween. By maintaining the burn-out circuit at low voltage, the metal chips are burned away and the inductor is not energized in such a manner that the work-piece is heated prematurely. Although Seyfried was an advance in the art, the device has several shortcomings. First, the device suffers from a significant decrease in production time. In operation, Seyfried allows the scales to accumulate until a shorting would occur. Then, it shuts off the primary circuit and activates the secondary circuit. The secondary circuit or auxiliary circuit burns and eliminates the metal scales. By shutting down the primary circuit and waiting for the secondary circuit to burn off the metal scales, significant production time is lost. An additional drawback of Seyfried is the complexity and therefore increased cost of the device. It requires an additional complicated circuit. If a problem arises with the auxiliary circuit, it will likely be a difficult problem to fix. Accordingly, there is a need in the industry to provide for an improved apparatus capable of effectively threading soft or limp metal through an induction heater that is also capable of removing scales produced during heating. The present invention contemplates a new and improved apparatus having such advantages. BRIEF SUMMARY OF THE INVENTION In accordance with the present invention there is provided a threading and metal scale removing device comprising a heating apparatus for heating a work-piece. The heating apparatus has an inlet through which the work-piece is threaded and an outlet through which the work-piece exits. A plurality of rollers are operatively associated with the heating apparatus. At least one rotatable belt is mounted on the plurality of rollers. The belt is adapted to thread the work-piece through the heating apparatus and remove metal scales that form and flake off the work-piece during heating. A motor is operatively connected to the rollers for driving the rollers thereby causing the belt to rotate through the heating apparatus. In accordance with another aspect of the present invention, there is provided a metal scale removing device comprising a heating apparatus for heating a work-piece. The heating apparatus has and inlet through which the work-piece is fed and an outlet through which the work-piece exits. A plurality of rollers are operatively associated with the heating apparatus. A rotatable belt is mounted on the plurality of rollers and is adapted to catch metal scales that have fallen from the work-piece and transport the metal scales away from the heating apparatus. One advantage of the present invention is the provision of a new threading device for induction heaters. Another advantage of the present invention is the provision of a new and improved scale removing device for induction heaters. Yet another advantage of the present invention is the provision of a belt rotatably disposed within an induction heater capable of effectively threading soft or limp metal material through the induction heater. Still another advantage of the present invention is the provision of a belt rotatably disposed within an induction heater having the ability to remove metal scales that form and flake off metal materials during heating. Still further advantages of the present invention will become apparent to those of ordinary skill in the art upon reading and understanding the detailed description of the preferred embodiment. BRIEF DESCRIPTION OF THE DRAWINGS The invention may take physical form in certain parts and arrangements of parts, preferred embodiments of which will be described in detail in this specification and illustrated in the accompanying drawings which form a part hereof, and wherein: FIG. 1 is a schematic view of a threading and scale removal device in accordance with the teachings of the present invention; and FIG. 2 is perspective view of the present invention operating solely as a scale removing device. DETAILED DESCRIPTION OF THE INVENTION Referring now to the drawings wherein the showings are for purposes of illustrating the preferred embodiments of the invention only and not for purposes of limiting the same, FIG. 1 shows a threading and scale removing device used in conjunction with an induction heater. However, it will be appreciated that the present invention may be used in conjunction with any conventional heating apparatus requiring threading of soft metal and/or scale removal. With reference to FIG. 1, an induction heater A includes an inlet 12 through which a work-piece 10 , such as a metal strip of steel or aluminum, is received. The work-piece 10 is threaded through the entry 12 and undergoes treatment before exiting through an outlet 14 located at the other side of the induction heater A. Upper and lower induction coils 18 , 20 are disposed within the induction heater for applying heat to the work-piece. Frames 11 and 13 support the coils 18 , 20 . In the illustrated embodiment, the work-piece 10 is soft and limp as it approaches the inlet 12 of the induction heater, having already been heated by a continuous caster (not shown) or other heating device. As such, a first tension roll set 26 is provided for receiving the work-piece and applying tension to the metal strip before it enters the induction heating assembly. Additionally, a first table roll 28 is disposed adjacent the first tension roll for receiving the strip metal from the tension roll and supporting the limp work-piece as it approaches the induction heater. Since the strip metal 10 is still limp when it reaches the inlet 12 of the induction heater A, a threading means is provided to effectively transfer the workpiece through the induction heater. The threading means preferably includes a belt 30 adapted to rotate through the induction heater. The belt is formed from a non-metallic material that is not affected by varying the magnetic field applied by the induction heater. The belt is mounted on a series of water cooled rollers 32 , 34 , 36 , 38 disposed around the periphery of the lower half of the induction heater A. The rollers are preferably located at the four corners of the substantially rectangular lower half of the heater. An optional tension roller 40 is disposed between the two lower rollers 36 , 38 and floats in the bracket 39 for desired tensioning of the belt. A belt motor 50 drives the rollers causing the belt to rotate in a clock-wise manner. As best seen in FIG. 1, the limp work-piece falls onto the belt 30 upon entering the induction heater. Accordingly, the belt supports the work-piece as it travels through the heating device. In a preferred embodiment, the belt and the work-piece travel at the same rate so as to prevent abrasion between the belt and the strip-metal. Upon exiting the outlet 14 of the induction heater A, a second table roll 60 bites or grabs the work-piece 10 . The strip travels over the second table roll and through a second tension roll 62 . At this point, the tension applied by the second tension roll lifts the work-piece from the belt so that all slack in the strip metal is eliminated. As a result, the work-piece is fully extended along the dotted line of FIG. 1 and is no longer in contact with the belt 30 . While passing through the induction heater, the belt is exposed to extremely high temperatures emitted from the work-piece. Therefore, the belt is preferably made from a material capable of withstanding elevated temperatures, such as a ceramic material. Additionally, it is beneficial to cool the belt and minimize its exposure to these elevated temperatures. One way to accomplish this is by increasing the speed of the belt after the belt has taken a fully extended position. Once the belt is fully extended and no longer in contact with the work-piece, the rate of travel of the strip is not critical. Thus, the belt speed can be increased thereby minimizing the amount of time the belt is in the induction heater. An air spray device 64 or the water cooled rollers are used to help cool the belt. In operation, a work-piece 10 travels through a first tension roll 26 onto a the first table roll 28 . The work-piece proceeds toward the inlet 12 of the induction heater A where the belt 30 threads the work-piece through the induction heater. Upon exiting the heater at the outlet 14 , the second table roll 60 bites or grabs the work-piece and transfers it to the second tension roll 62 . The tension applied by the second tension roll and the table rolls causes the work-piece to become fully extended and separated from the belt 30 . The work-piece continues to travel through the induction heater in this manner until threading is again required. However, the belt can also support the end of the strip as it exits the coil. Another significant function of the belt in the present invention is its ability to remove scales that form and flake from the work-piece as it passes through the induction heater A. In almost all induction heaters where significant amounts of heat are added to a work-piece, oxygen reacts with the work-piece to form metal oxide scales on the surface of the work-piece. As the induction heater continues to heat the metal material, the scales begin to flake off the surface of the work-piece. In a conventional induction heater, the scales fall into the interior of the heating device causing a number of problems, including short-circuiting. However, the belt 30 in the present invention prevents such problems. After the belt has threaded the work-piece 10 through the heating apparatus, it functions as a metal scale removing device. More particularly, the belt rotates beneath the work-piece thereby catching the scales that fall from the work-piece and transporting them away from the heating device. As such, the scales are prevented from falling into the interior of the heating device and causing the many problems already discussed. In operation, a work-piece 10 such as strip metal is threaded through the inlet 12 of the induction heater. As the temperature increases, metal scales begin to flake from the surface of the work-piece. The belt 30 , which moves in the same direction as the work-piece, catches the metal scales and carries them away from the induction heater. Once the belt reaches the outlet 14 of the induction heater, it makes a downward 90° turn. Inertia causes the metal scales to be separated from the belt into a chute 70 positioned adjacent the induction heater. The scales fall through the chute onto a conveyer 80 which transports and ultimately disposes of the scales. It must be appreciated that the metal scale removing aspect of the present invention may be incorporated into any type of induction heater or heating device, even when the threading aspect is not necessary. For example, FIG. 2 illustrates the metal scale removing device of the present invention in conjunction with an induction heating coil B for treating slabs. In this illustrated embodiment, a work-piece 10 , such as a slab, is fed through the induction heating coil B. Since slabs are not limp or flimsy, the threading aspect of the invention is immaterial and is not utilized in this environment. As such, the invention acts only as a scale removing device and the table rolls and tension rolls of FIG. 1 are not required. However, at least one table roll 28 may be used to support and guide the work-piece as is shown in FIG. 2 . After the work-piece has entered the heating apparatus and scales begin to fall from the slab, a belt 30 , driven by rollers 32 , 34 and moving in the same direction as the slab 10 , catches the scales and transports them away from the coil. The metal scales fall through a chute 70 into a conveyor 80 for ultimate disposal (See FIG. 1 ). As FIG. 2 illustrates, not all induction heaters need a threading device. In fact, most work-pieces are not soft and limp and therefore do not need a special threading device. Therefore, the present invention may be used solely as a metal scale removing device for any heating apparatus without having to incorporate the threading aspect of the invention. When only the scale removing aspect is desired, the table rolls and tension rolls of FIG. 1 are eliminated. However, when threading is required, the table rolls and tension rolls are provided and the belt functions as both the threading device and the scale removal device. The invention has been described with reference to the preferred embodiments. Obviously modifications and alterations will occur to others upon a reading and understanding of this specification. For example, a second belt 90 could be disposed on the top half of the induction heater as shown in FIG. 1 to be used either in conjunction with the first belt 30 or in place of the first belt. In addition, the length of the belt may be varied in order to use a lower belt temperature rating. The present invention is intended to include all such modifications and alterations in so far as they come within the scope of the appended claims or equivalents thereof

A threading and scale removing device is disclosed which includes a heating apparatus having an inlet and an outlet. A work-piece is fed through the inlet and exits through the outlet. A plurality of rollers are operatively associated with the heating apparatus. A belt is mounted on the plurality of rollers and is adapted to rotate through the heating apparatus. As the belt rotates, it functions to thread the work-piece through the heating apparatus. Once the work-piece has been threaded through the heating apparatus, the belt functions to catch and remove metal scales that flake from the work-piece during heating. A motor is operatively connected to the plurality of rollers for driving the rollers and allowing the belt to rotate through the heating apparatus.

BACKGROUND OF THE INVENTION There is a growing need for low cost, lightweight, low profile, readily mass-producible, high aperture-efficiency antennas of useful bandwidth in a variety of mass market applications. The desirable characteristics of low cost, lightweight, low profile and mass producibility are provided in general by printed circuit antennas. The simplest forms of printed circuit antennas are "microstrip" antennas wherein flat conductive elements are spaced from a single essentially continuous ground element by a single dielectric sheet of uniform thickness. Such antennas are easily constructed from one layer of double clad circuit board material. Microstrip antennas with increased aperture efficiency and increased bandwidth would be very desirable. One type of microstrip antenna utilizes radiating monopoles, each of which produce an omnidirectional radiation pattern in the plane of the antenna surface. Such an antenna is disclosed in U.S. Pat. No. 3,377,592 wherein short sections of otherwise uniform microstrip transmission lines are displaced in one direction from the centerline of the transmission line at intervals of one wavelength. All the outside corners of any one transmission line acquire the same charge simultaneously to produce monopoles and a radiation pattern that has a principal lobe that is tangential to the surface of the antenna. A second type of microstrip antenna utilizes thin conductive resonant dipole radiator elements, each of which produces a radiation pattern having a principal lobe broadside (perpendicular) to the antenna surface. Each of such dipole radiator elements has two orthogonal coordinates that respectively define E and H planes of electromagnetic radiation for that radiator element. The E coordinate dimension of each radiator element is approximately one-half the dielectric wavelength λo√ε r μ r , where λo is the free space wavelength, ε r is the relative dielectric constant and μ r is the relative permeability of the dielectric sheet. The dielectric sheet is generally λo/100√ε r μ r to λo/10√ε r μ r Thick with the preferred range being λo/75√ε r μ r to λo/15√ε r μ r . In an antenna it is desirable that such radiator elements radiate in a predetermined amplitude and phase relationship with respect to each other. The amplitude relationship may be a uniform illumination wherein all radiator elements contribute equally to a radiation pattern. Alternatively, the amplitude relationship may be a tapered distribution. The radiator elements should radiate in phase with respect to each other to create a broadside beam. An off-broadside beam may be created by having a progressive phase shift along rows or columns of radiator elements. One class of microstrip antennas utilizing resonant dipole radiator elements employs capacitative coupling of energy to radiator elements. Such an antenna is disclosed in U.S. Pat. No. 3,016,536 wherein rectangular resonant dipole radiator elements are distributed on a broad surface. The E coordinate dimension of each radiator element is approximately λo/2√ε r μ r . The H coordinate dimension of each radiator element is considerably less than the E coordinate dimension. Such radiator elements form collinear arrays in the E coordinate direction with capacitative coupling between radiator elements for energy transfer. The center dipole of each collinear array consists of a pair of quarter wavelength radiator elements that form a balanced center-fed dipole. Several center-fed dipoles and their respective collinear arrays are driven from a balanced line to provide a two dimensional planar array. Such an antenna requires a balanced drive, has a poor aperture efficiency and a narrow bandwidth. The antenna has a rather large thickness because it is designed to use the ground plane as a reflector. Another example of resonant dipole microstrip antennas utilizing capacitative coupling is contained in EMI-Varian Limited Bulletin PA2 11/73, entitled "Printed Antennae 2 - 36 GHz." In such an antenna the radiator elements are capacitatively coupled at various spacings to one or more feedlines running parallel to their E coordinate. The disclosed antenna has demonstrated low aperture efficiencies and poor side lobe control. A second class of microstrip antennas utilizing resonant dipole radiator elements employs conductive coupling of energy to radiator elements. Antennas of this class are disclosed in U.S. Pat. Nos. 3,803,623 (Charlot) and 3,811,128 (Munson) and by Munson (I.E.E.E. Transactions on Antennas and Propagation, January, 1974, pp. 74-78). The E coordinate dimension of the radiator elements is approximately λo/2√ε r μ r . The H coordinate dimension is commonly greater than the E coordinate dimension and may be several wavelengths long. The individual input impedance of such radiator elements at frequencies around resonance is typically in the convenient range of 50 to 150 ohms depending on element dimensions and dielectric substrate characteristics. A corporate feed network distributes energy between the transmission line and a plurality of microstrip radiator elements. A corporate feed network in microstrip comprises an interconnected pattern of thin conductive strips which connect the radiator elements into arrays. A terminal on the corporate feed network of an array serves for connection to a transmission line. Such a terminal may be connected directly to the transmission line or connected indirectly to the transmission line through additional corporate feed network strips. A corporate feed network may be provided by a sequence of power dividers and tapered feed line sections or other impedance transformers which serve to distribute the desired amount of energy directly from (to) the transmission line to (from) each radiator element. The lengths of the feed line sections determine the phase relationship between the transmission line and each radiator element and thus control the phase relationship between radiator elements. Two-dimensional arrays of up to four or possibly eight radiator elements interconnected by a corporate feed network can be designed to produce a good aperture efficiency in the range of 90 percent based on ground element area. For arrays of greater numbers of radiator elements a decreased aperture efficiency is observed with conventional corporate feed because the corporate feed network becomes increasingly more extensive. The more extensive feed network necessitates increasing the spacing between the radiator elements, with such increased radiator element spacing in turn significantly reducing the aperture efficiency. Such proliferating feed lines also become lengthy which increases feed line losses. The proliferating feed lines often have lengths of various multiples of dielectric wavelengths such that slight changes in frequency produce undesirable phase shifts between radiator elements. SUMMARY OF THE INVENTION The present invention provides improved distribution of energy to resonant dipole radiator elements in a microstrip antenna. Antennas utilizing the present invention can be designed to have an increased efficiency and an increased bandwidth when compared to other microstrip antennas utilizing resonant dipole radiator elements. The present invention utilizes thin conductive strips called bridge elements to distribute power to and control the phase relationship between such radiator elements. Each bridge element has a length providing approximately a phase reversal (in the range of 150° to 210° from end to end at the operating wavelength λo. Each bridge element directly and conductively joins two adjacent radiator elements with those two radiator elements being defined as being in the same array. The width of each bridge element is less than the H coordinate dimension of one of the radiator elements it joins and less than one-half the H coordinate dimension of the other radiator element it joins. Each array utilizing the present invention has a terminal on a radiator element off that radiator element's H coordinate. Such a terminal connects the array to an unbalanced transmission line either directly, or indirectly through a further feed network. In contrast, arrays utilizing corporate feed networks have terminals on the corporate feed network, which terminals connect the arrays to a transmission line. The present invention utilizes the phase reversal property that exists across a dipole radiator element in the E coordinate direction to distribute energy via one or more bridge elements to other radiator elements within the array. Accordingly, there is at least one radiator element in an array of the present invention which has either 1. two bridge elements, or 2. a bridge element and a terminal for connection to a transmission line joined to it at points of opposite phase. A simple form of the invention is a linear array of radiator elements that are series connected by bridge elements to form a chain-like structure of radiator elements that may or may not physically lie in a straight line. In a straight-line linear array having only one radiator element connected directly to a transmission line and operating as a transmitter antenna, power from the transmission line is distributed to the radiator elements that are electrically farther from the transmission line through the series connected radiator and bridge elements that are electrically closer to the transmission line. In a straight-line linear array having only one radiator element connected directly to a transmission line and operating as a receiver antenna, the increments of power received by other radiator elements pass through the series connected radiator and bridge elements that are electrically closer to the transmission line. Antennas utilizing the present invention do not require an elaborate corporate feed network and thus provide high efficiency by minimizing feed network losses and permitting close spacing of radiator elements. High efficiency antennas can achieve a desired antenna gain with a relatively small area of circuit board, thus offering the additional advantage of low weight and low cost. Antennas utilizing the present invention have surprisingly resulted in a significant increase in half-power bandwidth compared to conventional resonant dipole microstrip antennas. Therefore, antennas utilizing the present invention have a low sensitivity to changes in frequency and in the properties of the dielectric sheet. Antennas with uniformly illuminated arrays are easily designed with the present invention because they can be formed from modular building blocks. For example, a linear straight-line array may be easily formed once the geometries of the radiator element and bridge element are established by simple repetition of such elements. Once one array is formed, simple repetition may provide a plurality of arrays. Because each array requires only one terminal for connection to a transmission line, a plurality of such arrays can be formed into an antenna by a simple and hence easily designed corporate feed network. Arrays of the present invention are unexpectedly easy to match to common feed line impedances. In a typical situation the impedance at a terminal on one radiator element of an array may be inherently matched to 50 ohms with a voltage standing wave ratio (VSWR) of less than 1.5. The input impedance to one element is commonly capacitative; however, the addition of successive elements in an array progressively shifts the input impedance toward and into the inductive region. Such a resistive-inductive impedance can be easily compensated to become purely resistive by adding a small capacitative tab on the edge of the element having the terminal, with such a tab later being fabricated as part of the circuit board. If a terminal on an array for connection to a transmission line is on a central radiator element of the array, that radiator element can serve as a 180° phase shifter such that one terminal can be used to feed signals to or accept signals from radiator elements on both sides of such central radiator element to produce an antenna array whose beam direction is very stable with respect to changes in frequency and in the dielectric sheet properties such as dielectric constant and thickness. To a first order approximation, the E coordinate dimension of a dipole radiator element in relation to the dielectric constant determines a possible range of operating frequency for the radiator element. To a similar first order approximation, the bridge element which interconnects two radiator elements determines the phase relationship between the two radiator elements when they are operating as an antenna. In an array that utilizes the present invention and has a broadside beam, to a first order approximation there is 180° of phase shift across each radiator element and each bridge element such that each radiator element is in phase (360°) with respect to adjacent radiator elements with which it is interconnected. The radiator elements can be various sizes and shapes. The E coordinate dimension of each radiator element should be approximately λo/2√ε r μ r . The H coordinate dimension can be various lengths. The H coordinate dimension is greater than the width of the bridge element and may be several wavelengths long. If the H coordinate dimension is greater than about one dielectric wavelength, multiple bridge elements may be required between two radiator elements. Preferably the natural resonant frequency modes in the E and H coordinate dimensions for any given radiator element are different. Because the radiator element H coordinate is greater than the width of the bridge element, the characteristic impedance of the radiator elements considered as a section of transmission line will be lower than the characteristic impedance of the bridge elements. The individual radiator elements may be symmetrical or asymmetrical and each radiator element can conceivably have a different shape. While the radiator elements are often physically located adjacent to each other in the E coordinate direction, they can be physically located in other directions on the surface of the antenna dielectric sheet. However, it is important that the E coordinates of the respective radiator elements be approximately parallel regardless of the physical location of the radiator elements such that their radiation patterns will reinforce each other in a predetermined manner. The bridge elements can be various sizes and shapes as long as they provide approximately a phase reversal (150° to 210°) from end to end at the operating wavelength λo. Bridge elements can vary in width with narrower bridge elements having a higher characteristic impedance when considered as sections of a transmission line. Such characteristic impedance can be determined from Wheller's Wide Strip Approximation Chart (Microwave Engineers Handbook, Vol. I, 1971, publisher: Horizon House-Microwave Incorporated, p. 137) which gives impedance in terms of strip width, dielectric constant and dielectric thickness. It is believed that if bridge elements get too narrow they will not effectively transmit energy. Maximum bridge element width is such that the bridge element is less than the H coordinate dimension of one of the radiator elements it joins and less than one-half the H coordinate dimension of the other radiator element it joins. It is believed that if the bridge elements are too wide they will interfere with the ability of the radiator element to radiate. For a given bridge element the length is adjusted to provide the desired phase relationship. Relatively speaking, a narrower bridge element will have a longer length for the same phase shift. Once an array of the present invention is built, it is believed that similar arrays can be designed to operate at other desired frequencies by suitably scaling the array pattern and dielectric sheet thickness in the approximate ratio of the desired wavelength to the wavelength of the working model. BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic perspective view of a first embodiment of an antenna according to the present invention; FIG. 2 is a plan view of a second embodiment of an antenna according to the present invention; FIG. 3 is a Smith Chart showing the complex input impedance of antennae constructed as in FIG. 2 with one to four radiator elements; FIG. 4 is a plan view of a third embodiment of an antenna according to the present invention; FIG. 5 is a fragmentary drawing showing the relationship between the radiator and bridge elements in FIG. 4; FIG. 6 is a plan view of a fourth embodiment of an antenna according to the present invention; FIG. 7 is a plan view of a fifth embodiment of an antenna, one that has a plurality of arrays, each of which utilizes the present invention; FIG. 8 is a plan view of an array that is essentially identical to each of the arrays in FIG. 7; FIG. 9 is a fragmentary drawing showing the relationship between a feed terminal, a radiator element and a bridge element of the array in FIG. 8; and FIG. 10 is a plot of the E and H plane radiation patterns of the antenna in FIG. 7. DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, an antenna 20 includes a dielectric sheet 21 which uniformly separates a ground element 22 from radiator elements 31 through 36, bridge elements 41 through 45 and a capacitative tab 46. The antenna 20 is made from a double copper-clad low-loss dielectric sheet 21 by etching one copper layer to form radiator elements 31 through 36, bridge elements 41 through 45 and capacitative tab 46. The dielectric sheet 21 is polytetrafluoroethylene reinforced with glass fiber cloth with the sheet having properties in accordance with U.S. military specification MIL-P-13949E Grade GX with a relative dielectric constant ε r of about 2.45, a relative permeability μ r of 1.0 and a thickness of about 0.76 mm. Each copper layer is about 34 micrometers thick. The rectangular radiator elements 31 through 36 are each 1.38 cm by 2.05 cm and are located on 2.54 cm centers. Each bridge element 41 through 45 is 0.2 cm wide and conductively joins a pair of adjacent radiator elements diagonally across the space between them. The dielectric sheet 21 and the ground element 22 are each 2.54 cm by 14.7 cm in the broad surface. The antenna is fed at terminal 47 from a 50-ohm unbalanced coaxial transmission line (not shown) that passes through the ground element from the backside. The antenna has a broadside beam (principal lobe perpendicular to the antenna surface) at 6406 MHz, has about 90% aperture efficiency based on ground element area when matched with the tab 46 and has an input voltage standing wave ratio (VSWR) of 1.3 terminating a 50-ohm line at such frequency. It is believed the broadside beam indicates all radiator elements are in phase with respect to each other. The aperture efficiency figure includes the VSWR mismatch and is based on the theoretical gain G = 4πA/(λo) 2 where A is the ground element area and λo is the free space wavelength. The antenna's first side lobes in the E plane pattern of maximum gain are 12.6 db and 14.2 db below maximum gain. The antenna's measured half-power beam width in the E plane at frequency of maximum gain is 14.2°. The theoretical beam width for a uniformly illuminated aperture 14.7 cm long is 16.1°. Such theroetical beam width is based on the formula (50.6) (λo)/L where λo is the free space wavelength and L is the length of the aperture (ground element) in that plane. The antenna's beam is frequency steerable over a total angle of 20° when the frequency is scanned from 6112 MHz to 6742 MHz. Applicant believes that when the array in FIG. 1 is operating as an antenna with a broadside beam, to a first order approximation there is a phase reversal respectively across each radiator and bridge element. For example, radiator element 32 would have 180° of phase shift between points 52 and 53; and bridge element 42 would have 180° of phase shift between points 53 and 54 where it conductively joins radiator elements 32 and 33. Thus radiator elements 32 and 33 would be in phase with respect to each other. Under such circumstances, it is believed that the incident currents, resonant currents and reflected currents all synchronously reinforce each other. For example, the incident currents entering radiator element 32 at 52, the reflected currents entering radiator element 32 at 53 and the resonant currents within radiator element 32 would synchronously reinforce each other. It may be desirable to slightly shorten the E coordinate dimension of the radiator element 36 electrically farthest from the terminal 47 to optimize performance. It is believed that this adjusts the phasing of the reflected currents and compensates for the absence of additional bridge and radiator elements. The bridge elements in FIG. 1 each join a pair of adjacent radiator elements diagonally across the space between such radiator elements, permitting close spacing of radiator elements for high efficiency. Such an arrangement drives adjacent radiator elements such as 32 and 33 on opposite sides of their respective E coordinates such as at 52 and 54 such that any cross polarization of the E fields in adjacent radiator elements is self-canceling in the far field. By connecting bridge elements such as 41 and 42 to a radiator element such as 32 at points such as 52 and 53 which define a line parallel to the E coordinate dimension, the currents passing through the radiator element are parallel to and add to the resonant currents within the radiator element. If bridge elements 42 and 44 were arranged such that they were parallel to bridge elements 41, 43 and 45 while still joining their respective radiator elements diagonally across the space between such radiator elements, the antenna would still radiate but the radiated E plane would be slightly skewed from the E coordinate direction of the radiator elements. A second embodiment utilizing the present invention is an antenna 60 shown in FIG. 2. Its elliptical radiator elements 61 through 64 each have an E coordinate dimension of 1.52 cm, an H coordinate dimension of 2.03 cm and are located on 3.0 cm centers. Bridge elements 71 through 73 are each 0.2 cm wide and conductively join respective radiator elements along a center line as shown. A capacitative tab 74 is for impedance matching. The antenna is fed at terminal 75 from an unbalanced 50-ohm coaxial transmission line (not shown). A dielectric sheet 76 and a ground element (not shown) are each 2.54 cm by 11.5 cm in the broad surface. The antenna 60 has an efficiency of about 78 percent at 6959 MHz, the frequency of maximum gain, when properly matched to a 50-ohm line. Its principal lobe is tilted 3° to 8° off broadside depending on frequency away from terminal 75, indicating the bridge elements are slightly longer than those for a broadside beam. The antenna 60 will not operate efficiently at a frequency that is low enough to bring the principal lobe to broadside. FIG. 3 represents the complex input impedance at terminal 75 as a function of frequency on a Smith Chart normalized to 50 ohms without a matching tab 74 as the antenna 60 was built starting with element 61 and successively adding units of one bridge element and one radiator element. Curves 77, 78, 79 and 80, respectively, represent the complex impedance with 1, 2, 3 and 4 radiator elements. As successive units of one bridge element and one radiator element were added, the resistive impedance in the neighborhood of 6950 MHz remained relatively constant while the capacitative reactance progressively decreased. In the four-element configuration the complex impedance moved into the inductive region. FIG. 3 shows that the four element array has an inherent unmatched minimum VSWR of 1.83 at about 6960 MHz. By proper placement of the capacitative tab 74, the input VSWR for the four element array was reduced to less than 1.2 over the range 6950 to 7000 MHz. The impedance, referenced to the back side of the board where the coaxial center conductor passes through a hole in the ground element to attach to terminal 75, was measured using a slotted line impedance meter. By adjusting the size and location of the capacitative tab it is possible to not only reduce the VSWR but also move the frequency of minimum VSWR around in a limited range. Prior to making such an adjustment an array of radiator and bridge elements is established. Then, a movable tab is made from pressure-sensitive copper foil tape such as Scotch brand Electrical Tape No. X1194. The tab is made sufficiently large such that it can project beyond and overlap the radiator element having the feedpoint. The tab is adjusted while the terminal is connected by a coaxial connector through the ground element to a VSWR bridge such as Wiltron Company Model 64A50, 3 to 8 GHz. The swept frequency output from the bridge is observed on an oscilloscope while a tab is moved along the periphery of the radiator element having the terminal with the tab's size and location being varied. It has been observed that far more versatility is achieved in reducing VSWR and in adjusting the frequency of minimum VSWR than would be expected by a simple theory of pure capacitative shunting. Once the size and location of a tab is determined it may be reproduced as part of the copper-clad etching process. Although the array in FIG. 3 is impedance matched to a transmission line at terminal 75, the radiator elements are not impedance matched to their respective bridge elements within the array itself. FIG. 4 shows a third embodiment wherein the dielectric sheet 81 is 1.5 mm thick. The elliptical radiator elements 82 through 92 each have an E coordinate dimension of 1.52 cm, an H coordinate dimension of 2.03 cm and are located on 2.54 cm centers. The bridge elements 93 through 102 are each 0.25 cm wide and conductively join to the radiator elements as shown in the fragmentary drawing of FIG. 5. The dimensions A are 6.35 mm. Capacitative tabs 103 and 104 are attached to element 87. This antenna is fed by an unbalanced 50-ohm coaxial transmission line, the center conductor of which passes through the ground element and contacts terminal 105 on radiator element 87. By placing the terminal 105 on a central radiator element, it is possible to drive the radiator elements on both sides of element 87 in phase while utilizing element 87 as both a phase reversing element and a radiator element. This central feed provides a desired broadside beam direction that is substantially independent of variations in frequency and variation in the dielectric constant and thickness of the dielectric sheet. This antenna exhibits side lobes 16.2 db and 17.5 db below maximum gain which is believed to indicate the radiation pattern can be tapered by using long arrays. The half-power beam width of the antenna is 8.5° compared to a theoretical beam width of 8.1° if the aperture were uniformly illuminated. By placing tabs 103 and 104 on radiator element 87 the input VSWR was reduced to less than 1.05. The array in FIG. 4 has a bandwidth of 5% within which the input VSWR remains less than 1.7. It is believed that interaction among elements of the array maintains the input VSWR of arrays, particularly those with many elements, at a desirably low value over a large frequency range. FIG. 6 shows a fourth embodiment wherein the dielectric sheet 111 is 0.76 mm thick. Each of the rectangular radiator elements 112 through 120 have an E coordinate dimension of 1.38 cm and they are on 2.30 cm centers. The H coordinate dimension of radiator elements 112, 113 and 114, 115 and 116, 117 and 118, 119 and 120 are respectively 2.95 cm, 1.84 cm, 1.33 cm, 0.82 cm and 0.6 cm. The bridge elements are each 0.2 cm wide, approximately 1.5 cm long and they are attached to their respective radiator elements as shown with the dimension B being 0.8 cm. A terminal 121 for connection to an unbalanced transmission line and a capacitative matching tab 122 are on radiator element 112. Radiator elements 115 and 116 have slits cut in them as shown to minimize cross polarization because these elements are almost square. The antenna in FIG. 6 exhibits side lobes 19 db and 20 db below maximum gain which is believed to indicate the radiation pattern can be tapered by varying the size of the radiator elements. The half-power beam width of this antenna is 12.3° compared to an estimated theoretical beam width of 10.4° if the aperture were uniformly illuminated. FIG. 7 shows a fifth embodiment wherein eight essentially identical three element arrays 125 are fed by a conventional corporate power divider feed network 126 that includes two 180° phase shifters. FIG. 8 shows a three element array 125 that is essentially identical to those in FIG. 7. Dielectric sheet 130 and a ground element (not shown) are 2.48 cm by 7.2 cm. The dielectric sheet is 0.76 mm thick. Elliptical radiator elements 131, 132 and 133 each have an E coordinate dimension of 1.52 cm, an H coordinate dimension of 2.03 cm and are located on 2.54 cm centers. Bridge elements 134 and 135 are each 0.2 cm wide. A terminal 136 for connection to an unbalanced transmission line is on radiator element 133. FIG. 9 shows in a fragmentary drawing the location of the terminal 136 and the bridge element 135 with respect to radiator element 133. The dimension C is 0.4 cm and the dimension D is 0.5 cm. The bridge elements 134 and 135 join the radiator elements 131 and 132 in similar fashion. The three element array 125 in FIG. 8 has a maximum gain at approximately 6770 MHz with unmatched terminal 136 connected to a 50-ohm transmission line. The efficiency of this array approaches 100% based on ground element area and has an unmatched VSWR of less than 1.4 into a 50-ohm input at 6774 MHz. Referring again to FIG. 7, eight arrays 125, essentially identical to the array in FIG. 8, are shown interconnected by a conventional type corporate feed network 126. The dielectric sheet 140 is 9.2 cm by 15.0 cm by 0.76 mm and the arrays 125 are spaced on 2.30 cm centers in the H coordinate direction as shown by dimension F. The arrays 125 are spaced apart 2.92 cm in the E coordinate with such spacing being center to center between adjacent radiator elements in different arrays as shown by dimension G. A terminal 136 on each array is connected to a 100-ohm one-eighth wavelength section of line 141 which impedance matches and converts the complex impedance at terminal 136 to approximately 85 ohms pure resistive at the other end of the line 141. Two of the lines 141 are combined to produce 42.5 ohms at reference character 142 with this line being tapered and combined again by corporate feed network techniques well known in the art. To protect the antenna pattern in FIG. 7 from the environment, it was covered with a 0.38 mm thick sheet of similar dielectric material. This additional sheet was heat bonded to the etched surface of the antenna using a 0.038 mm layer of polymonochlorotrichloroethylene film fused in place under 50 psi at 400°F (204°C). FIG. 10 is a plot of the E and H field patterns of the antenna in FIG. 7 referenced to 0 db. The observed gain exceeds 90% of the theoretical gain based on ground element area at 6650 MHz with the first side lobes in the E plane being down 12 db and 12.5 db from maximum gain. The bandwidth over which the input VSWR is less than 2.0 is 285 MHz or 4.3%.

Microstrip antenna having one or more arrays of resonant dipole radiator elements. The radiator elements have an E coordinate dimension of approximately λo/2√ ε r μ r . Bridge elements directly and conductively join adjacent pairs of radiator elements to provide energy distribution and the desired phase relationship. The radiator elements and bridge elements are in a broad surface which is uniformly spaced from a ground element by a dielectric sheet.

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation of U.S. patent application Ser. NO. 11/148,543 to Moffat et al., filed Jun. 8, 2005, which is a continuation in part of U.S. patent application Ser. No. 10/656,840 to Moffat et al., filed Sep. 5, 2003. BACKGROUND [0002] 1. Field of the Invention [0003] This invention relates to the coating of substrates, and in particular to an apparatus and process for the efficient coating of substrates using chemical vapor reaction and gas plasma cleaning. [0004] 2. Description of the Related Art [0005] The application of coatings onto substrates and other workpieces is required as a process step in many industrial fields. An example of such a process is the coating of a silicon wafer with a layer of Hexamethyldisalizane (HMDS). This coating process is used to promote the adhesion of organic layers such as photoresist to the inorganic silicon wafer. The HMDS molecule has the ability to adhere to the silicon wafer and also to be adhered to by an organic additional layer. For example, silicon wafers would be baked for 30 minutes in a 150 C oven for 30 minutes to dehydrate them. The silicon wafers would then be sprayed with HMDS. The excess HMDS would then be spun off of the silicon wafer. A typical process of this type would result in a HMDS monolayer on the surface of the silicon wafer. [0006] A problem encountered with the above mentioned process was that if the silicon wafer was not sufficiently dry prior to the application of HMDS, then residual moisture would interfere with the reaction of the HMDS to the silicon wafer. This would result in variations in the HMDS layer reaction and then could lead to voids in the subsequently applied next layer. Another problem with a process of this type is that HMDS would rapidly deteriorate when exposed to air and moisture, and thus such a process required a large amount of HMDS to provide a small amount of reaction. [0007] Because of the problems relating to variations in the HMDS monolayer, processes for the coating of substrates with HMDS evolved. Later processes more thoroughly dehydrated the silicon wafer substrate prior to the application of HMDS, and limited the HMDS from much, if any, exposure to air and moisture. An example of such a process would be as follows. Silicon wafers would be placed in a vacuum chamber and cycled back and forth between vacuum and preheated hot dry nitrogen in order to dehydrate the silicon wafer. For example, the silicon wafer would be exposed to a vacuum of 10 Ton for 2 minutes. At this pressure water boils at about 11 C. The vacuum chamber would then be flooded with preheated nitrogen at 150 C. This part of the process would heat the surface of the silicon wafer so that the high temperature of the wafer would assist in the dehydration process as vacuum was once again applied. After 3 complete cycles, a vacuum of 1 Torr would be applied to complete the dehydration process. [0008] The next step in such a process is to open a valve between the vacuum chamber and a canister of HMDS. At room temperature the HMDS boils at approximately 14 Ton and thus the chamber is flooded with 14 Torr of HMDS vapor. In this process the HMDS is not exposed to air or moisture and the silicon wafer is significantly dryer prior to being coated. [0009] Some coating processes based on the above mentioned type of process require a higher pressure. The HMDS is preheated to create a higher vapor pressure. Typical figures are preheating of the HMDS to 100 C to produce up to 400 Ton pressure or HMDS vapor while limiting the pressure in the process oven at 300 Torr to avoid condensation of the HMDS. [0010] Processes involving the preheating of the deposition chemicals have the drawback that if the deposition chemicals degrade with exposure to heat then the bulk preheating of these chemicals may result in the loss of the unused residual chemical. These chemicals are often very expensive. Also, many of these chemicals are hazardous materials. The less of these chemicals actually being used in the process at any time reduces the potential risk for processing facilities. [0011] The coating of substrates for biotech applications may require sufficiently dehydrated substrates and insertion into the process chamber of one or more deposition chemicals which have been preheated and/or vaporized prior to insertion. Some coatings for biotech applications are quite expensive. Some coatings are difficult to vaporize and vaporization requires a combination of low pressure and high temperature. Without reduced pressure, the temperature required for vaporization may be too high to retain stability of the chemical to be vaporized. Biotech applications may require silane deposition onto glass and/or other substrates as a bridge to organic molecules. Among the silanes used are amino silanes, epoxy silanes, and mercapto silanes. These silanes are used in the adhesion layer between glass substrates and oligonucleotides. Oligonucleotides are a short DNA monomer. Substrates are coated with a monolayer of silane as a bridge between the inorganic substrate and the organic oligonucleotide. A silane coated substrate with an oligonucleotide layer is now a standard tool used in biotech test regimens. One area where this oligonucleotide layer is used is in the formation of DNA microarrays. A uniform and consistent silane layer leads to a more uniform and consistent top surface of the oligonucleotide layer, which in turn leads to more useful test results. [0012] What is called for is a process and apparatus which withdraws deposition chemicals from a bulk storage container and then preheats and/or vaporizes this portion separately prior to delivery into the process chamber, allowing for the introduction of deposition chemicals at high temperatures and/or vapor pressures into a process chamber, without requiring preheating of bulk amounts of the deposition chemicals. What is also called for is an apparatus which is able to plasma clean substrates in the chamber into which the vaporized chemicals will be delivered, and an apparatus which can clean itself after such production runs using plasma. [0013] Substrates coated with such a process have reduced contamination, have more consistent monolayers with better bonds to the substrate, allowing for a more consistent oligonucleotide layer. This consistent substrate, used in DNA microarray tests, leads to more accurate test results SUMMARY [0014] A process for the coating of substrates comprising insertion of a substrate into a process oven, dehydration of the substrate, plasma cleaning of the substrate, withdrawal of a metered amount of one or more chemicals from one or more chemical reservoirs, vaporizing the withdrawn chemicals in one or more vapor chambers, and transfer of the vaporized chemicals into a process oven, thereby coating the substrate. An apparatus for the coating of substrates comprising a process oven, a gas plasma subsystem, a metered chemical withdrawal subsystem, a vacuum subsystem, and a vaporization subsystem. BRIEF DESCRIPTION OF THE DRAWINGS [0015] FIG. 1 is a pictorial representation of portions of one embodiment of the invention highlighting the chemical withdrawal, infuse, and vaporization subsystems. [0016] FIG. 2 is a pictorial representation of portions of one embodiment of the invention highlighting the chemical withdrawal and infuse subsystems. [0017] FIG. 3 is a representational piping schematic of one embodiment of the present invention. [0018] FIG. 4 is a pictorial representation of portions of one embodiment of the present invention highlighting the vacuum and gas delivery subsystems. [0019] FIG. 5 is a front isometric view of one embodiment of the present invention. [0020] FIG. 6 is a rear isometric view of one embodiment of the present invention. [0021] FIG. 7 is a partial cutaway side view of one embodiment of the present invention. [0022] FIG. 8 is a blown up section of the partial side view of FIG. 7 . [0023] FIG. 9 is a side view of one embodiment of the present invention. [0024] FIG. 10 is a rear view of one embodiment of the present invention. [0025] FIG. 11 is a top view of one embodiment of the present invention. [0026] FIG. 12 is a rear view of one embodiment of the present invention. [0027] FIG. 13 is a partial cutaway view of one embodiment of the present invention. [0028] FIG. 14 is a view of the process oven interior according to one embodiment of the present invention. [0029] FIG. 15 is a view of the process oven interior according to one embodiment of the present invention. [0030] FIG. 16 is a view of the process oven interior according to one embodiment of the present invention. [0031] FIG. 17 is a view of the process oven with its door open according to some embodiments of the present invention. [0032] FIG. 18 is a partial view of one embodiment of the present invention displaying the metering pumps. [0033] FIG. 19 is a partial view of one embodiment of the present invention displaying the metering pumps. DETAILED DESCRIPTION [0034] In one embodiment of the present invention, as seen in FIG. 1 , chemical vapor deposition apparatus 101 has a fluid input portion 102 , a vaporization portion 103 , and a process oven 104 . Process oven 104 may be controlled with regard to both temperature and pressure. Fluid reservoirs 106 , 107 provide the chemicals for the fluid input portion 102 . Fluid reservoirs 106 , 107 , may be manufacturer's source bottles in some embodiments. Fluid reservoirs may contain the same fluid, allowing for the easy replacement of one reservoir if empty without disruption of the deposition process, or may contain separate chemicals. In some applications, water may be used as one of the chemicals in order to facilitate some rehydration of the substrate. [0035] Chemicals in the fluid reservoirs 106 , 107 , are withdrawn into fluid input portion 102 by syringe pumps 108 , 109 . Although syringe pumps are used in this embodiment, other methods of withdrawal may be used, including peristaltic pumps and other appropriate methods. Chemical withdraw valves 116 , 117 , provide isolation between fluid reservoirs 106 , 107 , and syringe pumps 108 , 109 . Chemical withdraw valves 116 , 117 , are opened prior to withdrawal of chemicals from fluid reservoirs 106 , 107 . [0036] Chemical infusion valves 113 , 114 provide isolation between syringe pumps 108 , 109 , and the vapor chamber 110 . The vapor chamber 110 is surrounded by vapor chamber heater 118 . Although the vapor chamber heater is external to the vapor chamber in this embodiment, the vapor chamber heater may be internal to the vapor chamber or integral to the vapor chamber. The vapor chamber heater 110 may be P/N MBH00233 manufactured by Tempco, of Wood Dale, Ill., or other suitable heater. The vapor chamber 110 is fluidically coupled to process oven 104 by heated vapor line 111 . The vapor chamber 110 may be isolated from process oven 104 by the operation of heated vapor valve 115 . An example of such a heated vapor valve is valve P/N SS-8BK-VV-1C by Swagelok of Sunnyvale, Calif., with heater P/N 030630-41 by Nor-Cal Products of Yreka, Calif. The vapor chamber manometer 112 monitors the pressure inside vapor chamber 110 . The process oven 104 may contain one or more trays 105 . [0037] In one embodiment of the present invention, as seen in FIG. 2 , fluid input portion 102 routes chemicals from the fluid reservoir 106 through a delivery pipe 203 to the chemical withdraw valve 116 . An example of such a chemical withdraw valve 116 is P/N 6LVV-DP11811-C manufactured by Swagelok of Sunnyvale, Calif. A fluidic coupler 211 is inserted into fluid reservoir 106 to allow fluid withdrawal from the fluid reservoir 106 . In this embodiment, the fluid reservoirs 106 , 107 , are chemical source bottles. The fluidic coupler 211 also allows fluid such as dry nitrogen gas from pipe 202 to be inserted into the chemical reservoir 106 to fill the volume voided by the removal of chemical from the chemical reservoir 106 . Exposure of the chemical to air and/or moisture is thus minimized. The syringe pump 206 may withdraw chemicals from fluid reservoir 106 when the chemical withdraw valve 116 is opened. An example of the syringe pump 206 is P/N 981948 manufactured by Harvard Apparatus, of Holliston, Mass. Actuation of the syringe pump mechanism 207 withdraws chemicals from the fluid reservoir 106 by partially or fully withdrawing the syringe plunger 208 from the syringe body 209 . The amount of chemical withdrawn may be pre-determined, and also may be pre-determined with accuracy. The chemical is routed from the fluid reservoir 106 , through the fluidic coupler 211 and the delivery pipe 203 to the chemical withdraw valve 116 , through a pipe 214 and a T-coupler 205 to the syringe body 209 in this embodiment. In general, fluidic coupling can be referring to liquid or gas coupling in this embodiment. [0038] After withdrawal of chemicals into the syringe body 209 , the chemical withdraw valve 116 may be closed to isolate the delivery pipe 203 . The chemical infusion valve 113 may then be opened to link the syringe body 209 to the vapor chamber 110 . An example of such a chemical infusion valve 113 is P/N 6LVV-DP11811-C manufactured by Swagelok of Sunnyvale, Calif. The syringe pump mechanism 207 may then re-insert the syringe plunger 208 partially or fully into the syringe body 209 , forcing the chemical within the syringe body 209 through the T-coupler 205 and then through pipe 210 . With the chemical infusion valve 113 open, the chemical then may enter the vapor chamber 110 via pipe 215 . Pressure within the vapor chamber 110 is monitored with the vapor chamber manometer 112 . An example of such a manometer is a 0-100 Ton heated capacitance manometer P/N 631A12TBFP manufactured by MKS of Andover, Md. [0039] The fluid reservoir 106 is secured with a spring clamp 212 within a source bottle tray 213 . The source bottle tray 213 may also act as a spill containment vessel. [0040] In some embodiments of the present invention, the fluid input portion 102 delivers the desired amount of chemical in another way. The chemicals in the fluid reservoirs are withdrawn in a pre-determined amount using a metering pump. For example, the metering pump may withdraw and deliver 2 milliliters per stroke. To deliver a specific quantity of a chemical, the metering pump would be pumped repeatedly until the desired quantity had been delivered. In some embodiments using metering pumps, the chemical withdraw valve and the chemical infusion valve are not necessary. The metering pump itself acts to isolate the fluid reservoir from the vapor chamber. Such embodiments allow for the delivery of the chemical from the fluid reservoir with less required hardware. [0041] FIGS. 18 and 19 are partial cutaway views of an embodiment using metering pumps. The metering pumps 1801 are fluidically coupled to the vapor chamber. Chemical reservoirs 1802 , 1803 are the source of supply of the liquid which the metering pumps 1801 pump into the vapor chamber (some piping is omitted in the Figures). [0042] One of skill in the art will understand that the fluid input portion may have other embodiments that may use the above described elements in different types of combinations, or may use different typed of elements. [0043] In one embodiment of the present invention, as seen in FIG. 3 , piping and other hardware is arranged as illustrated in the piping schematic 401 . Vacuum and gas portion 402 illustrates the portion of the apparatus with inputs for gas and the provision of vacuum. In one embodiment of the present invention, a high pressure gas inlet 403 connects to 80-100 psig nitrogen, an inlet 404 connects to 5-15 psig of a process gas, and an inlet 405 connects to 15-40 psig nitrogen. A vacuum inlet 406 provides vacuum to the system. [0044] The high pressure gas inlet 403 provides gas via a line 464 to the chemical reservoirs 502 , 503 , and also provides the pressure to actuate valves 463 and valves 480 - 484 . Solenoids 421 - 427 are directed by a logic controller at I/O locations 440 - 445 to actuate valves 480 - 485 using solenoids 421 - 427 . The gas from the high pressure gas inlet 403 is reduced in pressure to 4 psig by a pressure reducer 460 to be fed to the chemical reservoirs. [0045] The solenoid acutated valves 430 , 431 are triggered by directions from a logic controller at I/O interfaces 454 , 455 to allow for purging of the chemical source bottle feed line 490 . [0046] When the solenoid 421 is directed by the logic controller via the I/O interface 440 , high pressure gas is directed through a line 471 to actuate the chemical infusion valve 480 , which connects the fluid line 510 from the syringe pump 512 to the vaporization chamber 501 . When the solenoid 422 is directed by the logic controller via the I/O interface 441 , high pressure gas is directed through the line 470 to actuate the chemical infusion valve 481 , which connects the fluid line 511 from the syringe pump 513 to the vapor chamber 501 . [0047] When the solenoid 426 is directed by the logic controller via the I/O interface 444 , high pressure gas is directed through the line 467 to actuate valve 483 which allows for the introduction into the process chamber 500 of gas from the inlet 404 . When the solenoid 425 is directed by the logic controller via the I/O interface 443 , high pressure gas is directed through the line 465 to actuate the valve 485 , which allows for the introduction into the process chamber 500 of gas from the inlet 405 . [0048] When the solenoid 427 is directed by the logic controller via the I/O interface 445 , high pressure gas is directed through a line 468 to actuate the heated vapor valve 484 , which allows for the introduction into the process chamber 500 of vaporized chemical from the vapor chamber 501 via line 554 . Temperature indicating controller 524 and temperature alarm high switch are coupled to I/O interface 451 . [0049] Solenoid operated valves 428 , 429 allow the opening and closing of lines between the chemical reservoirs 502 , 503 and the syringe pumps 512 , 513 . I/O interfaces 458 , 459 control the operation of the solenoid operated valves 428 , 429 . [0050] The level of chemical left in the chemical reservoirs 502 , 503 is monitored with level sensors 514 , 515 and routed to the logic controller via the I/O interfaces 456 , 457 . Level sensors 514 , 515 are capacitance level switches P/N KN5105 by IFM Effector of Exton, Pa, in this embodiment. [0051] The vapor chamber pressure switch 464 is linked directly by a line 472 to a solenoid actuated valve 423 , which, when triggered, in turn triggers the gas actuated overpressurization limit relief valve 463 . The overpressurization limit relief valve 463 connects the vapor chamber 501 to the vacuum line inlet 406 . The vapor chamber pressure switch 464 triggers when the pressure in the vapor chamber 501 exceeds a preset pressure, which is 650 Torr in this embodiment. [0052] The process oven manometer 461 feeds its signal to the logic controller via an analog interface (not shown). Overtemperature alarm 551 feeds its signal to the logic controller via I/O interface 448 . An I/O interface 442 controls the solenoid actuated valve 424 , which in turn can trigger the gas actuated heated vacuum valve 482 via a line 466 , which links the process oven 500 to the vacuum inlet 406 . A temperature monitor 527 monitors the vacuum line temperature and is linked to the logic controller via an I/O interface 460 . Temperature alarm high switch 552 is linked to the logic controller via an I/O interface 460 . [0053] Temperature monitors 520 , 521 , 522 , 523 monitor the temperature in the process oven 500 . Temperature monitors 520 , 521 , 522 , 523 are linked to the logic controller by an RS-485 interface (not shown). Alarms are present in the temperature monitoring system and are linked to the logic controller by I/O interfaces 446 , 447 , 449 , 450 . [0054] Temperature monitors 524 , 525 connected to I/O interfaces 451 , 453 are also used to monitor the temperature of the heated vapor line 526 and the vapor chamber 501 . A pressure monitor 462 is linked to the logic controller by an analog interface and overtemperature alarm 553 is linked to the logic controller by an I/O interface 452 . [0055] A logic controller may be used to control this apparatus in some embodiments. An example of such a controller is Control Technology Corporation Model 2700 of Hopinkton, Mass. One of skill in the art will understand that the apparatus may be controlled using a variety of suitable methods. [0056] In one embodiment of the present invention, as seen in FIG. 4 , a chemical vapor deposition apparatus 101 has a vacuum subsystem 701 . Vacuum is applied to the vacuum subsystem 701 vacuum input supply line 735 . A heated vacuum valve 703 may be actuated to isolate the heated vacuum line 704 from the vacuum input supply line 735 . An example of the heated vacuum valve is P/N SS-8BK-VV-1C manufactured by Swagelok of Sunnyvale, Calif. The vacuum in the process chamber is measured using the chamber manometer 705 . An example of such a manometer is P/N 631A13TBFP manufacture by MKS of Andover, Md. Vacuum input supply line is fluidically coupled to the overpressurization limit relief valve 710 . An example of such a overpressurization limit relief valve is P/N SS-BNVS4-C manufactured by Swagelok of Sunnyvale, Calif. Overpressurization limit relief valve 710 couples vacuum input supply line 735 to line 709 . T-coupler 707 links line 708 , line 709 , and line 736 . Line 736 is fluidically coupled to vapor flask overpressurization limit switch 706 . The overpressurization limit switch 706 is electrically connected to a solenoid actuated valve which supplies high pressure gas that actuates the overpressurization limit relief valve 710 . An example of the vapor flask overpressurization limit switch is P/N 51A13TCA2AF650 by MKS of Andover, Md. Line 708 is fluidically coupled to vapor chamber 110 . [0057] A low pressure gas distribution manifold 733 distributes gas such as dry nitrogen for use in dehydration cycles. Inert gas such as dry nitrogen may be used in these lines. A purge manifold 732 allows for the purging of the fluid reservoirs and lines. The low pressure gas input line 522 is split at a T-coupler 723 into two serpentine lines 720 . Gas line heaters 721 allow for the pre-heating of the gas prior to delivery of the process chamber. T-couplers 724 , 729 further divide the delivery lines prior to input to the chamber at the gas inlets 725 , 726 , 727 , 728 . [0058] A high pressure gas distribution manifold 731 provides gas for purge manifold 732 which inserts low pressure nitrogen into the fluid reservoirs 106 , 107 . A line 730 routes gas to a fluidic coupler 211 in order to replace the volume voided by chemical withdrawal. Inert gas such as dry nitrogen may be used in these lines. The low pressure regulator 741 reduces the pressure from the high pressure gas distribution manifold 731 upstream from purge manifold 732 . The low pressure regulator 741 then provides gas to the purge manifold 732 . [0059] High pressure gas distribution manifold 731 provides high pressure gas that is routed to the gas actuated valves by the triggering of solenoid actuated valves in valve bank 740 . [0060] An alternative process gas distribution inlet 734 provides another inlet for process gas that may be used in some processes using this embodiment of the present invention. In this embodiment, the process gas lines are fluidically coupled to the low pressure gas lines upstream of the serpentine lines 720 . [0061] As seen in FIG. 5 , chemical vapor reaction apparatus 1001 has a touchpanel interface 1002 . The light tower 1003 signals status of the apparatus to persons in the vicinity. Door 1004 provides access to the process chamber. [0062] In some embodiments of the present invention, as seen in FIGS. 14 through 16 , the process oven 104 houses a plasma gas generation system. The plasma gas generation system resides predominantly within the process oven chamber walls 1401 . The gas plasma generation system is adapted to generate gas plasma within the process oven 104 . [0063] FIGS. 14 to 16 show several variations of capacitive plasma generation. Plasma may be generated with an appropriate gas in the presence of a strong electric field at an appropriate pressure. Capacitive plasma generation typically uses parallel plate electrodes to create the electric field. Electrodes may also be used to reduce the charging potential of a plasma and to concentrate the plasma in selected areas. [0064] Capacitive plasma electrodes are commonly referred to as being electrically active, electrically grounded, or electrically floating. An electrically active electrode has a high voltage, typically 400-600 volts, placed on it to create an electric field with respect to other electrodes. The voltage is typically alternating current at a high frequency. The industry standard frequency for plasma equipment is 13.56 MHz. There are advantages to using a lesser frequency in the 40 to 50 KHz range. An electrically grounded electrode is connected to ground with a appropriate conductor so that it remains at ground voltage potential. An electrically floating electrode is isolated from all other electrical potentials and will be at some voltage level that depends on the influence of the plasma upon it. [0065] FIG. 14 shows a horizontal electrode configuration that spans the process oven 104 . Plasma is generated primarily between active electrodes 1402 and grounded electrodes 1403 . Product material to be processed is typically place on the floating electrodes 1404 . To reach the product, plasma must pass through the perforated grounded electrode 1403 . Passing through the grounded electrode 1403 reduces the charging influence of the plasma and therefore reduces the charge that may be induced on the surface of product material by exposure to the plasma. [0066] FIG. 15 shows a vertical electrode configuration with grounded product trays 1411 . Plasma is primarily generated between active electrodes 1410 and grounded electrodes 1412 . Plasma passes through the perforated, grounded electrodes 1412 and reduces it charging influence. The region between the grounded electrodes 1412 has no electric field and therefore no plasma generation. However, plasma concentrates in regions with zero electric fields when plasma generation is at relatively low frequencies, 40-50 KHz. The configuration of FIG. 15 therefore concentrates plasma with low charging influence around grounded product trays 1411 . [0067] FIG. 16 shows a configuration similar to that of FIG. 15 with an additional plasma generation region in the center of the chamber 104 . Plasma is primarily generated between active electrodes 1420 and grounded electrodes 1422 , Once again, product trays 1421 are electrically grounded and in a region where plasma is concentrated but with low charging influence. [0068] In some embodiments, the product trays 1404 span the process oven 104 . Active electrodes 1402 and ground electrodes 1403 span the process oven 104 horizontally. The RF power supply, cabling, and RF power feed through are known in the art. [0069] In some embodiments, the plasma cleaning cycle may occur before the dehydration process. In an exemplary process, the chamber is evacuated. A gas is then introduced into the chamber and the pressure is stabilized at a low pressure, such as 150-200 milliTorr. In some embodiments, the introduced gas in oxygen. In some embodiments, the introduced gas is a combination of oxygen and argon. In some embodiments, other gasses are used. [0070] The plasma gas generation system allows for plasma gas cleaning of a work piece, such as a slide or substrate, in the same chamber as that in which subsequent process steps will take place. This gives many advantages, including reducing possible contamination that may occur if the work piece is exposed to the environment after plasma cleaning. Also, the plasma gas generation system can be used to clean the oven after the work pieces have been processed and removed. Many of the chemicals that may be used in processes that this chamber supports may leave residues that can interfere with subsequent runs. The plasma gas generation system may be utilized to clean the chamber after a process run and prior to loading the chamber with the work pieces for the next run. [0071] In some embodiments, as seen in FIG. 15 , the active electrodes 1410 and the ground electrodes 1412 may span the interior of the process oven 104 vertically. The product trays 1411 may span the process oven 104 horizontally between the ground electrodes 1412 . [0072] In some embodiments, as seen in FIG. 16 , there may be a plurality of vertical segments within the process oven 104 . The ground electrodes 1422 and the active electrodes 1420 reside vertically within the process oven 104 . The product trays 142 reside horizontally between ground electrodes 1422 . [0073] FIG. 6 shows a rear isometric view of apparatus 1001 . FIG. 7 is a partial cutaway side view of one embodiment of the present invention. FIG. 8 is a blown up section of the partial side view of FIG. 7 . FIG. 9 is a side view of one embodiment of the present invention. FIG. 10 is a rear view of one embodiment of the present invention. FIG. 11 is a top view of one embodiment of the present invention with the process door open. FIG. 12 is a rear view of one embodiment of the present invention. [0074] FIG. 13 is a cutaway view of the vacuum subsystem and the chemical reservoir purge subsystem. A manufacturer's chemical source bottle 1304 is the chemical reservoir in this embodiment. The purge regulator 1307 feeds the purge manifold 1306 with a gas such as nitrogen. A 5 psi relief valve 1308 is located downstream from the purge manifold in this embodiment. Gas is routed to the bottle 1304 via a line 1301 . Line 1301 connects to a fitting 1303 which routes the gas from line 1301 into the head portion of the source bottle 1304 . The withdrawal line 1302 couple to the fitting 1305 for withdrawal of the chemical from the source bottle 1304 . The tube supplying chemical to the withdrawal line 1302 terminates near the bottom of the inside of source bottle 1304 . Line 1301 is delivered gas from the purge manifold 1306 . [0075] A process for the coating of substrates in a process chamber, which may include dehydrating the substrate, gas plasma cleaning of the substrate, and vaporizing the chemical to be reacted prior to its entry into the process chamber. Subsequent to the processing of the substrate, the chamber may be cleaned using gas plasma. [0076] A substrate for the chemical deposition of different chemicals may be of any of a variety of materials. For biotech applications, a glass substrate, or slide, is often used. Glass substrates may be borosilicate glass, sodalime glass, pure silica, or other types. Substrate dehydration may be performed as part of some processes. The glass slide is inserted into the process chamber. The slide is then dehydrated. Residual moisture interferes with the adhesion of chemicals during the deposition process. Alternatively, dehydration of the slide allows for later rehydration in a controlled fashion. The dehydration process alternates exposing the glass slide to vacuum and then to heated nitrogen, either once or multiple times. For example, the glass slide would be exposed to a vacuum of 10 Ton for 2 minutes. At this pressure water boils at about 11 C. The vacuum chamber would then be flooded with preheated nitrogen at 150 C. This part of the process would heat the surface of the glass slide so that the high temperature of the slide would assist in the dehydration process as vacuum was once again applied. After 3 complete cycles, a vacuum of 1 Ton would be applied to complete the dehydration process. [0077] A gas plasma cleaning cycle may also be used in preparation of the substrate for coating. In a typical process, the substrate is cleaned using gas plasma after the dehydration process. In some embodiments, the plasma cleaning cycle may occur before the dehydration process. In an exemplary process, the chamber is evacuated. A gas is then introduced into the chamber and the pressure is stabilized at a low pressure, such as 150-200 milliTorr. In some embodiments, the introduced gas in oxygen. In some embodiments, the introduced gas is a combination of oxygen and argon. In some embodiments, other gasses are used. After the stabilization of the pressure in the process chamber, the electrodes are powered to generate the plasma. In an exemplary process, the electrodes are powered to 450 Volts cycled at 40 kiloHertz. The power cycle may last for 2 minutes in some embodiments. [0078] After the completion of the dehydration and plasma cleaning cycles, the slide or substrate is ready for chemical reaction. Chemical reservoirs, such as manufacturer's source bottles, provide the chemical for the deposition process. For many processes, silanes are used. Among the silanes used are amino silanes, epoxy silanes, and mercapto silanes. Chemical may be withdrawn directly from the reservoir. A metered amount of chemical is withdrawn from the chemical reservoir. This may be done by opening a valve between the chemical reservoir and a withdrawal mechanism. The withdrawal mechanism may be a syringe pump. Chemical is withdrawn from the reservoir, enters the syringe pump, and then the valve between the chemical reservoir and the syringe pump is closed. The chemical reservoirs may be purged with an inert gas such as nitrogen. This purging allows for the filling of the volume of fluid removed with an inert gas, minimizing contact between the chemical in the reservoir and any air or moisture. [0079] Next, a valve between the syringe pump and a vaporization chamber is opened. The vapor chamber may be pre-heated. The vapor chamber may be a reduced pressure. The syringe pump then pumps the previously withdrawn chemical from the syringe pump to the vaporization chamber. The vapor chamber may be at the same vacuum level as the process oven. In parallel to this delivery of chemical to the vaporization chamber, a second chemical may be undergoing the same delivery process. The two chemicals may vaporize at substantially the same time. Additionally, more chemicals may also be delivered to the vaporization chamber, or to another vaporization chamber. [0080] In some embodiments, the chemical or chemicals to be vaporized may be withdrawn from the reservoir or reservoirs in a specific metered amount. This specific amount of withdrawal and delivery to the vapor chamber may be repeated until the desired amount of chemical or chemicals has been delivered into the vapor chamber. For example, a metering pump may be used. The metering pump may deliver a pre-determined amount of chemical per stroke of the metering pump. The number of pump strokes may be selected, thus delivering a specified amount of chemical. [0081] The reduced pressure in the vapor chamber, and/or the elevated temperature in the vapor chamber may allow for the vaporization of chemicals at pre-determined pressure levels and temperatures. [0082] The vaporized chemical, or chemicals, are then delivered to the process chamber. This may be done by opening a valve between the vaporization chamber and the process oven after the chemical has vaporized in the vaporization chamber. Alternatively, the valve between the vaporization chamber and the process oven may already be open when the chemical, or chemicals, are delivered to the vaporization chamber. The chemical then proceeds into the process chamber and reacts with the substrate. [0083] In some embodiments, the chemical may be added into the vapor chamber with the valve between the vapor chamber and the process chamber open. The chemical may be continued to be added into the vapor chamber until the vapor pressure in the process chamber reaches a desired level. At that time, the valve between the vapor chamber and the process chamber may be closed. The chemical may then remain in the process chamber for the desired amount of time for reaction. [0084] In some embodiments, the chamber may be cleaned using gas plasma subsequent to the processing steps. The chamber may be emptied of all workpieces and then cleaned. The gas plasma cleaning step subsequent to the processing steps helps prepare the process chamber for subsequent processing. [0085] As evident from the above description, a wide variety of embodiments may be configured from the description given herein and additional advantages and modifications will readily occur to those skilled in the art. The invention in its broader aspects is, therefore, not limited to the specific details, representative apparatus and illustrative examples shown and described. Accordingly, departures from such details may be made without departing from the spirit or scope of the applicant's general invention.

A process for the coating of substrates comprising insertion of a substrate into a process oven, plasma cleaning of the substrate, dehydration of the substrate, withdrawal of a metered amount of one or more chemicals from one or more chemical reservoirs, vaporizing the withdrawn chemicals in one or more vapor chambers, and transfer of the vaporized chemicals into a process oven, thereby reacting with the substrate. An apparatus for the coating of substrates comprising a process oven, a gas plasma generator, a metered chemical withdrawal subsystem, and a vaporization subsystem.

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a memory device that can be shared by a plurality of chips such as a CPU (Central Processing Unit), a DSP (Digital Signal Processor), and more particularly to a memory device containing an arbiter performing arbitration for a bus access right. [0003] 2. Description of the Background Art [0004] Recently, systems equipped with CPU chips, memory chips and the like have attained high performance and multi-functions, and in addition to a CPU chip, a DSP, a chip having an operation function, such as a logic circuit (simply referred to as “logic” hereinafter) for performing a floating-point operation are often placed on-board. [0005] [0005]FIG. 1 is a block diagram showing an exemplary schematic configuration of a conventional system board having a CPU chip, a memory chip and the like thereon. The system board 101 includes memories 111 a - 111 c, a CPU 112 controlling the entire system, a DSP 113 processing data, and logic 114 performing processing including processing of an operation such as a floating-point operation. It is noted that system board 101 can externally input/output data through a system port. [0006] CPU 112 , logic 114 and DSP 113 are connected with memories 111 a , 111 b and 111 c through memory buses, respectively. CPU 112 , DSP 113 and logic 114 are connected through a system bus. [0007] CPU 112 mainly controls the entire system while accessing memory 111 . Logic 114 performs processing of an operation such as a floating-point operation while accessing memory 111 b . DSP 113 performs data processing while accessing memory 111 c . CPU 112 receives an operation result from logic 114 and a data processing result from DSP 113 through the system bus to control the system entirely. [0008] [0008]FIG. 2 is a block diagram showing an internal configuration of an asynchronous DRAM (Dynamic Random Access Memory) chip as exemplary memories 111 a - 111 c . This asynchronous DRAM chip includes a memory array 121 , an address input unit 122 externally inputting an address, an address decoder 123 decoding the address input from address input unit 122 , a command input unit 124 externally inputting a command, a control unit 125 interpreting the command input from command input unit 124 for control depending on the command, a data control unit 126 controlling writing data to memory array 121 and reading data from memory array 121 , and a data input/output unit 127 inputting/outputting data under the control of control unit 125 . [0009] Address decoder 123 selects a memory cell by decoding the address input from address input unit 122 and outputting the decoding result to memory array 121 . [0010] Control unit 125 interprets the command input from command input unit 124 to control a refresh operation, a precharge operation, a data reading operation, a data writing operation and the like. If the command is to read data, for example, data control unit 126 reads data from a memory cell selected by address decoder 123 and outputs data externally through data input/output unit 127 under the control of control unit 125 . [0011] [0011]FIG. 3 is a block diagram showing an internal configuration of a synchronous DRAM chip as another example of memories 111 a - 111 c . This synchronous DRAM chip includes a memory array 131 , an address input unit 132 externally inputting an address, an address decoder 133 decoding the address input from address input unit 132 , a command input unit 134 externally inputting a command, a control unit 135 interpreting the command input from command input unit 134 for control depending on the command, a clock input unit 136 externally inputting a clock signal, a control unit 137 performing a timing control in accordance with the clock signal input from clock input unit 136 , a data control unit 138 controlling writing data to memory array 131 and reading data from memory array 131 under the control of control unit 135 , and a data input/output unit 139 inputting/outputting data in synchronization with the clock signal output from control unit 137 . [0012] Address input unit 132 externally inputs an address in synchronization with the clock signal output from control unit 137 . Address decoder 133 selects a memory cell by decoding the address input by the address input unit 132 and outputting the decoding result to memory array 131 . [0013] Command input unit 134 externally inputs a command in synchronization with the clock signal output from control unit 137 . Control unit 135 interprets the command input by command input unit 134 to control a refresh operation, a precharge operation, a data reading operation, a data writing operation and the like. [0014] [0014]FIG. 4 is a block diagram showing another example of the schematic configuration of a conventional system board having a CPU chip, a memory chip and the like thereon. This system board 102 includes a memory 111 , a CPU 112 controlling the entire system, a DSP 113 processing data, logic 114 performing processing including processing of an operation such as a floating-point operation, and an arbiter 115 arbitrating for the right to access a memory bus. [0015] CPU 112 , DSP 113 and logic 114 are connected to memory 111 through the memory bus and share memory 111 . CPU mainly controls the entire system while accessing memory 111 . DSP 113 processes data while accessing memory 111 . Logic 114 performs processing of an operation such as a floating-point operation while accessing memory 111 . [0016] Arbiter 115 receives a request (Req) signal for acquiring the right to access memory 111 from CPU 112 , DSP 113 and logic 114 . The respective Req signals are provided with the priorities and arbiter 115 arbitrates for each request according to the respective priorities. Arbiter 115 then outputs an acknowledge (Ack) signal to that chip which acquires the right to access the memory bus. [0017] The chip that receives Ack signal outputs an address (Add) signal and the like and starts accessing memory 111 . Arbiter 115 controls memory 111 by outputting Add signal, a command and the like to memory 111 . [0018] [0018]FIG. 5 is a timing chart illustrating the operation of arbiter 115 mounted on system board 102 . In cycle 1, CPU 112 outputs Req signal for acquiring the right to access the memory bus to arbiter 115 . In cycle 2, arbiter 115 performs arbitration (Arb) for Req signal. At this point, there is no other chip that outputs Req signal, and therefore in cycle 3, arbiter 115 outputs Ack signal to CPU 112 . [0019] When CPU 112 receives Ack signal and recognizes that the right to access memory bus is acknowledged, in cycle 4, CPU 112 outputs Add signal and the like to arbiter 115 . At this point, arbiter 115 outputs Add signal, command (Act) and the like to activate memory 115 . In cycle 4, DSP 113 outputs Req signal to arbiter 115 . [0020] In cycle 5, arbiter 115 performs arbitration for Req signals for acquiring the right to access memory bus. Since CPU 112 is using the memory bus according to the priority, Ack signal is not output to DSP 113 . In cycles 6 to 9, arbiter 115 outputs a command to memory 111 in response to the request from CPU 112 and performs reading data (Read) or writing data (Write) from/to memory 111 . [0021] In cycle 9, logic 114 outputs Req signal to arbiter 115 . In this cycle, arbiter 115 completes reading data or writing data from/to memory 111 . [0022] In cycle 10, arbiter 115 performs arbitration for Req signals for acquiring the right to access memory bus. Since DSP 113 is using the memory bus according to the priority, Ack signal is not output to logic 114 . In this cycle, arbiter 115 outputs Ack signal to DSP 113 . [0023] In cycle 11, DSP 113 outputs Add signal and the like to arbiter 115 . At this point, arbiter 115 outputs Add signal, a command (Act) and the like to memory 111 to activate memory 111 . [0024] In cycles 13 to 16, arbiter 115 outputs a command to memory 111 in response to the request from DSP 113 and performs reading data (Read) or writing data (Write) from/to memory 111 . [0025] When arbiter 115 completes reading data or writing data from/to memory 111 , arbiter 115 outputs Ack signal to logic 114 in cycle 17. The similar processing is thereafter performed. [0026] In system board 101 shown in FIG. 1, no conflict over the memory access right occurs since the respective separate memories are connected to CPU 112 , DSP 113 and logic 114 . [0027] The number of memory chips mounted on system board 101 , however, is increased. As applications have increasingly attained high performance and multi-functions, the number of chips mounted on system board 101 has been increased accordingly, resulting in that the mounted area is inevitably increased. This contradicts the tendency for recent information terminal equipment to attain portability. [0028] In addition, since the capacity of a standard memory chip is defined beforehand, it is difficult to obtain a memory having a capacity required for CPU 112 , DSP 113 and logic 114 each. Therefore a memory having a capacity larger than the required capacity is often used. Unfortunately, this increases the cost for the entire system. [0029] On the other hand, in system board 102 shown in FIG. 4, the problem of system board 101 shown in FIG. 1 can be solved, since CPU 112 , DSP 113 and logic 114 share memory 111 . In the case where Req signals from CPU 112 and DSP 113 are in conflict as described above, however, Ack signal is not output to DSP 113 until the access to memory 111 by CPU 112 has been completed. Therefore the processing performance of the entire system is deteriorated. SUMMARY OF THE INVENTION [0030] An object of the present invention is to provide a memory device in which reduced processing performance of the entire system can be prevented. [0031] Another object of the present invention is to provide a memory device in which an increased area for mounting chips on a system board can be prevented. [0032] In accordance with an aspect of the present invention, a memory device includes a memory unit and an arbiter controlling the memory unit while arbitrating for bus access requests from a plurality of units. When a second bus access request takes place before an access to the memory unit that corresponds to a first bus access request has been completed, the arbiter performs activation of the memory unit that corresponds to the second bus access request in parallel with the access to the memory unit that corresponds to the first bus access request. [0033] Since the arbiter performs activation of the memory unit that corresponds to the second bus access request in parallel with the access to the memory unit that corresponds to the first bus access request, the access to the memory unit that corresponds to the second bus access request is allowed immediately after the access to the memory unit that corresponds to the first bus access request has been completed. As a result, processing performance can be improved. Furthermore, since a plurality of units can share the memory device, an increased area for mounting chips on the system board can be prevented. [0034] The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0035] [0035]FIG. 1 is a block diagram showing an exemplary schematic configuration of a conventional system board having a CPU chip, a memory chip and the like thereon. [0036] [0036]FIG. 2 is a block diagram showing an internal configuration of an asynchronous DRAM chip as an exemplary memories 111 a - 111 c. [0037] [0037]FIG. 3 is a block diagram showing an internal configuration of a synchronous DRAM chip as another example of memories 111 a - 111 c. [0038] [0038]FIG. 4 is a block diagram showing another example of a schematic configuration of a conventional system board having a CPU chip, a memory chip and the like thereon. [0039] [0039]FIG. 5 is a timing chart illustrating an operation of arbiter 115 mounted on system board 102 . [0040] [0040]FIG. 6 is a block diagram showing a schematic configuration of a system board in an embodiment of the present invention. [0041] [0041]FIG. 7 is a timing chart illustrating an operation of an arbiter 15 contained in memory 11 in the embodiment of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENT [0042] [0042]FIG. 6 is a block diagram showing a schematic configuration of a system board in an embodiment of the present invention. System board 1 includes a memory 11 , a CPU 12 controlling the entire system, a DSP 13 processing data, and logic 14 performing processing including processing of an operation such as a floating-point operation. Memory 11 includes an arbiter 15 arbitrating for the right to access a memory bus. Memory 11 has an internal configuration similar to that of the asynchronous DRAM chip shown in FIG. 2 or the synchronous DRAM chip shown in FIG. 3 except that it includes arbiter 15 , and therefore description thereof will not be repeated. [0043] Each unit such as CPU 12 , DSP 13 , or logic 14 is connected to memory 11 through the memory bus to share memory 11 . CPU 12 mainly controls the entire system while accessing memory 11 . Logic 14 performs processing of an operation such as a floating-point operation while accessing memory 11 . DSP 13 processes data while accessing memory 11 . [0044] CPU 12 , DSP 13 and logic 14 are connected to memory 11 through respective separate control buses 1 - 3 . Each of control buses 1 - 3 includes an address (Add) signal, a request (Req) signal for acquiring the right to access the memory data bus, and an acknowledge (Ack) signal for a request. [0045] Arbiter 15 receives Req signals for acquiring the right to access memory 11 from CPU 12 , DSP 13 and logic 14 . The respective Req signals are provided with priorities and arbiter 15 arbitrates for each request according to the priority. Arbiter 15 then outputs the acknowledge (Ack) signal to that chip which has acquired the right to access the memory bus. [0046] CPU 12 , DSP 13 and logic 14 start outputting Add signal before receiving Ack signal. When memory 11 is configured in DRAM with a bank configuration, a row address can be activated before the immediate preceding reading/writing cycle has been completed. Therefore in the present embodiment, memory 11 has arbiter 15 included therein and arbiter 15 has a plurality of address ports, so that arbiter 15 receives an address for the next reading/writing cycle to activate the row address in a different memory bank in advance before the immediate preceding reading/writing cycle has been completed. [0047] [0047]FIG. 7 is a timing chart illustrating the operation of arbiter 15 contained in memory 11 in the embodiment of the present invention. In cycle 1, CPU 12 outputs Req signal for acquiring the memory bus access right to arbiter 15 . In cycle 2, arbiter 15 performs arbitration (Arb) for Req signal. In cycle 3, since Add signal has already been output from CPU 12 , arbiter 15 outputs Add signal, a command (Act) and the like to memory 11 to activate a row address of a memory bank within memory 15 before outputting Ack signal. [0048] In cycle 4, arbiter 15 outputs Ack signal to CPU 12 since there is no other chip that outputs Req signal. In this cycle 4, DSP 13 outputs Req signal to arbiter 15 . [0049] In cycle 5, arbiter 15 performs arbitration for Req signal for acquiring the memory bus access right. Since CPU 12 is using the memory bus according to the priority, Ack signal is not output to DSP 13 . In cycles 5 to 8, arbiter 15 outputs a command to memory 11 in response to the request from CPU 12 and performs reading data (Read) or writing data (Write) from/to memory 11 . [0050] In cycle 6, since Add signal has already been output from DSP 13 , arbiter 15 outputs Add signal, a command (Act) and the like to memory 11 to activate a row address of a different memory bank within memory 11 . [0051] In cycle 8 in which arbiter 15 completes reading data or writing data from/to memory 11 , arbiter 15 outputs Ack signal to DSP 13 . In this cycle, logic 14 outputs Req signal to arbiter 15 . [0052] In cycles 9 to 12, arbiter 15 outputs a command to memory 11 in response to the request from DSP 13 and performs reading data (Read) or writing data (Write) from/to memory 11 . [0053] In cycle 9, arbiter 15 performs arbitration for Req signal for acquiring the memory bus access right. Since DSP 13 is using the memory bus according to the priority, Ack signal is not output to logic 14 . [0054] In cycle 10, since Add signal has already been output from logic 14 , arbiter 15 outputs Add signal, a command (Act) and the like to memory 11 to activate a row address of a different memory bank within memory 11 . [0055] In cycle 12 in which arbiter 15 completes reading data or writing data from/to memory 11 , arbiter 15 outputs Ack signal to logic 14 . The similar processing is thereafter performed. [0056] It is noted that although in the present embodiment it has been described that separate chips such as memory chip 11 , CPU 12 , DSP 13 , or logic 14 are mounted on system board 1 , these functions may be provided in the same chip as in a memory-embedded chip such as an SOC (System On a Chip) or an SIP (System In a Package). [0057] Inmost of the memory chips on system boards, a data bus width is at most ×32 bits (mainly ×16 bits). In the memory-embedded chip, however, the data bus width is sharply increased such as ×128 bits, ×256 bits, and the number of addresses is reduced with the increase in the number of bits. Therefore the configuration of the memory device in the present embodiment is more effective in the memory-embedded chip in which every unit is mounted on a single chip. [0058] It is noted that the configuration of the memory device in the present embodiment mounted on the memory-embedded chip differs from the configuration of system board 1 shown in FIG. 6 only in that the units including memory 11 , CPU 12 , DSP 13 , logic 14 and the like are mounted on a single chip. Therefore detailed description thereof will not be repeated. [0059] As described above, in accordance with the memory device in the present embodiment, memory 11 contains arbiter 15 , and arbiter 15 receives an address for the next reading/writing cycle to activate a row address in a different memory bank in advance before the immediate previous reading/writing cycle has been completed. As a result, the number of cycles required to access memory 11 can be reduced and the processing performance of the entire system can be improved. [0060] In addition, since CPU 12 , DSP 13 and logic 14 can share memory 14 , the increased area for mounting chips on system board 1 can be prevented. [0061] Although the present invention has been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of the present invention being limited only by the terms of the appended claims.

An arbiter performs activation of memory that corresponds to a bus access request from DSP in parallel with an access to memory that corresponds to a bus access request from CPU, when DSP requests to access the bus before the access to memory that corresponds to the bus access request from CPU has been completed. Therefore, immediately after the access to memory that corresponds to the bus access request from CPU has been completed, the access to memory that corresponds to the bus access request from DSP is allowed, thereby improving processing performance.

RELATED APPLICATIONS This application is a continuation application of U.S. application Ser. No. 12/462,312, filed Aug. 3, 2009, which is related to, and claims priority of, U.S. provisional application No. 61/086,678 filed on Aug. 6, 2008, by Donald Burn and Jack J. Stiffler. FIELD OF THE INVENTION This invention relates to software techniques and procedures for achieving fault tolerance in computer systems and, more particularly, to techniques and procedures for establishing and recording a consistent system state from which all running operating systems and applications can be safely resumed following a fault. BACKGROUND OF THE INVENTION “Checkpointing” has long been used as a method for achieving fault tolerance in computer systems. It is a procedure for establishing and recording a consistent system state from which all running applications can be safely resumed following a fault. In particular, in order to checkpoint a system, the complete state of the system, that is, the contents of all processor and input/output (I/O) registers, cache memories, and main memory at a specific instance in time, is periodically recorded to form a series of checkpointed states. When a fault is detected, the system, possibly after first diagnosing the cause of the fault and circumventing any malfunctioning component, is returned to the last checkpointed state by restoring the contents of all registers, caches and main memory from the values stored during the last checkpoint. The system then resumes normal operation. If inputs and outputs (I/Os) to and from the computer are correctly handled, and if, in particular, the communication protocols being supported provide appropriate protection against momentary interruptions, this resumption from the last checkpointed state can be effected with no loss of data or program continuity. In most cases, the resumption is completely transparently to users of the computer. Checkpointing has been accomplished in commercial computers at two different levels. Early checkpoint-based fault-tolerant computers relied on application-directed checkpointing. In this technique, one or more backup computers were designated for each running application. The application was then designed, or modified, to send periodically to its backup computer, all state information that would be needed to resume the application should the computer on which it was currently running fail in some way before the application was able to establish the next checkpoint. This type of checkpointing could be accomplished without any specialized hardware, but required that all recoverable applications be specially designed to support this feature, since most applications would normally not write the appropriate information to a backup computer. This special design placed a severe burden on the application programmer not only to ensure that checkpoints were regularly established, but also to recognize what information had to be sent to the backup computer. Therefore, in general, application-directed checkpointing has been used only for those programs that have been deemed especially critical and therefore worth the significantly greater effort required to program them to support checkpointing. System-directed checkpointing has also been implemented in commercial computer systems. The term “system-directed” refers to the fact that checkpointing is accomplished entirely at the system software level and applications do not have to be modified in any way to take advantage of the fault-recovery capability offered through checkpointing. System-directed checkpointing has the distinct advantage of alleviating the application programmer from all responsibility for establishing checkpoints. System-directed checkpointing involves periodically establishing checkpoints in which the system state at that instant is recorded in such a way that, should a fault occur before reaching the next checkpoint, the system can be rolled back and the state that prevailed at the last checkpoint can be restored. Either of two basic methods is used to accomplish this. The first, called pre-image checkpointing, requires the contents of any page in memory to be copied to a checkpoint buffer before that page is allowed to be modified. The second, called post-image checkpointing, depends on the existence of a shadow memory with a shadow page for each page in main memory. On this case, when an attempt is made to write to a page in main memory, its address is captured and placed on an address queue. Following each checkpoint, all modified pages are copied into a shadow buffer and from there into the shadow memory. While system-directed checkpointing has obvious advantages over application-directed checkpointing, its implementation has traditionally been accomplished through the use customized hardware and software, making it virtually impossible for such systems to remain competitive in an era of rapidly advancing state-of-the-art commodity computers and operating systems. More recently, techniques have been disclosed for achieving system-directed checkpointing on standard computer platforms. These techniques, however, all require either modified hardware or else modifications to the operating system kennel. The first of these techniques involves modifying the hardware to capture the information needed to establish a checkpoint. This procedure is best implemented in the memory controller hardware, but unfortunately, standard memory controllers do not support the required functionality. The second technique entails modifying the operating system kernel to enable certain memory writes to be interrupted momentarily so that either the pre-image of the addressed section of memory, or the address itself, can be captured and recorded elsewhere in memory. The problem with this approach is that it can be implemented only on systems having operating systems that have been so modified. SUMMARY OF THE INVENTION A procedure is described for endowing otherwise standard computers with a high level of fault tolerance at a very modest incremental cost, without requiring either the hardware or the operating system kernel to be modified in any way. This procedure is implemented through the addition of a virtual operating system layer, called the “virtual layer”, the “virtual machine monitor” or the “hypervisor”, that sits between any standard operating system, called the “guest operating system”, and the computer hardware. Hypervisor layers have become increasingly prevalent in data centers and even in desktop computers because of the advantages they afford in system management, operating environment versatility and computer resource allocation. Conceptually, the hypervisor is a specialized operating system, but instead of hosting user applications, it serves as the host to other operating systems, which, in turn, host user applications. State-of-the-art processors provide support for hypervisor systems by, in effect, implementing three levels of operation, an application level, an operating system level and a hypervisor level. Each guest operating system controls a virtual computer and allocates that computer's resources in the normal way. But any attempt to allocate the computer's physical, as opposed to virtual, resources, results in a trap to the hypervisor. The hypervisor, in response to such a trap performs the operation on behalf of the host operating system, but, depending on the specific operation and on the circumstances under which it is attempted, it may, in accordance within the present invention, extend the operation so as to support checkpointing and other fault tolerant features. When the hypervisor is implemented as detailed herein and used in conjunction with the checkpointing and rollback procedures described in U.S. Pat. No. 6,622,263, standard computers can be rendered fault tolerant without requiring any of the hardware or software customizations normally associated with fault-tolerant computers. All applications, host operating systems and input/output subsystems receive the benefit of fault tolerance without having to be modified in any way. BRIEF DESCRIPTION OF THE DRAWINGS The above and further advantages of the invention may be better understood by referring to the following description in conjunction with the accompanying drawings in which: FIG. 1 is a block schematic diagram of a generic memory-mapping scheme showing the mapping from the guest operating system's virtual addresses to its pseudo-physical addresses and from those addresses to actual physical addresses. FIG. 2 is a flowchart of the hypervisor's response to a request from a guest operating system for an I/O operation. FIG. 3 is a flowchart of the hypervisor's response to a request-complete message from an I/O device. FIG. 4 is a flowchart illustrating the process by which the hypervisor effects a checkpoint and preserves I/O integrity. FIG. 5 is a flowchart showing the procedure for implementing a rollback following a fault. DETAILED DESCRIPTION A hypervisor-based computer system is described that periodically captures and checkpoints relevant system-state information and, when used in concert with the checkpointing and fault-recovery procedures described in U.S. Pat. No. 6,622,263, can convert any standard computer running any standard operating system into a fault-tolerant computer. This state information is naturally segregated on a per-guest-operating-system basis and can be captured separately for each guest OS or captured simultaneously for the entire system as a whole. In the latter case, if the hypervisor also checkpoints its own state, the entire system can be rolled back, affording protection against faults encountered in running hypervisor code as well as those encountered by any of the guest operating systems. Used in this way, the methodology described in U.S. Pat. No. 6,622,263 covers hypervisor implementations in an obvious way, with the term “operating system” used in that disclosure replaced by “hypervisor” and the term “application” replaced by “guest operating system”. Consequently, the present invention focuses on the case in which each guest operating system is checkpointed independently of all the others and, following a fault, is rolled back to its last checkpoint and restarted without impacting those other guest operating systems. In this case, the state of the hypervisor itself is not checkpointed so no attempt is made to recover should the hypervisor encounter a bug in its own code. However, it should be obvious to anyone reasonably versed in the state of the art that both methods can be implemented simultaneously, giving the hypervisor the option recovering from a fault either by rolling back a single guest OS or, should that fail or the fault appear to be global in nature, by rolling back the entire system. Hypervisor modifications that support fault tolerance can be segregated into three basic components: 1. Memory management subsystem—responsible for managing physical memory and tracking modifications to it and for segregating it into partitions, some for use by guest operating systems and some for its own use. 2. Device emulator subsystem—responsible for managing virtual input/output (I/O) device emulators. The emulators present generic I/O devices to the guest operating systems. In many hypervisor implementations, these emulators are integrated into a virtual I/O processor (VIOP). 3. Checkpointing and recovery subsystem—implements the checkpoint and recovery operations required for fault tolerance. 1) Memory Management Subsystem The memory manager is the key hypervisor component for providing checkpointing support. Its primary function is to allocate physical memory not only to itself but also to the potentially multiple operating systems being hosted on the same computer. It presents to each guest operating system a block of memory that appears to be physically contiguous although it may in fact be composed of an arbitrary set of pages located anywhere in physical memory. As with all operating systems, the translation from virtual addresses to physical memory addresses is accomplished using a set of page tables. Hypervisor memory-manager subsystems, however, also manage, in addition to the normal physical page tables, a set of pseudo-physical page tables, here called the guest page tables, for each guest operating system. These page tables give the guest operating system the illusion that it is managing physical memory, but they are mapped into memory as read-only so that any modification to them can be reflected in the physical page tables managed by the hypervisor itself. The hypervisor memory manager also maintains a page database, including information about the user of that page (guest operating system, I/O subsystem, etc.), whether the page is read-only, and, if the processor supports multiple page sizes, the size of the page and its decomposition into a set of smaller physical pages. An illustrative mapping from a virtual address used by an application to an address in physical memory is shown in FIG. 1 . The virtual address space 101 consists of a linear array of addresses used by each application to access physical memory and memory-mapped I/O locations. Each virtual address in that space is partitioned into several segments used to access successive levels in the virtual-to-physical mapping hierarchy. FIG. 1 shows a two-level map for translating virtual addresses into pseudo-physical page addresses combined with a second two-level map for translating pseudo-physical addresses into physical page addresses, but more or fewer levels may be used in an obvious extension of the mapping described here. The term “pseudo-physical address” is used here to denote the address into which the guest operating system maps the virtual address on question. (The term “guest address space” will be used to denote the pseudo-physical address space associated with a specific guest operating system.) The first segment of the virtual address ( 102 ) is a directory offset or pointer to a word stored in guest directory 105 ; the directory is a page stored in pseudo-physical memory at a location identified by the guest-directory base address 107 , which is loaded at by the guest operating system into a processor register dedicated to that purpose. This word is in turn the address of a second page, the guest page table 103 , also stored in pseudo-physical memory. The second segment of the virtual address ( 103 ) is a table offset that points to a word in that table called here the virtual or pseudo-physical address. In the absence of a hypervisor, the pseudo-physical address reached at this point would serve as the actual physical address of a page in physical memory. Instead, it is converted by the hypervisor into a true physical address using a second set of translation tables. Segment 108 of the pseudo-physical address is a directory offset that points to a word in a directory in physical memory pointed to by the physical-directory base address register 112 . This dedicated processor register is loaded by the hypervisor and is unique to each guest operating system. As before, the word thereby extracted from the directory is the address of a physical page table 111 ; the second segment ( 109 ) of the pseudo-physical address is a table offset that identifies the word in the page table containing the address of the desired page ( 114 ) in physical memory. The last segment of the virtual address ( 104 ) is a data offset that points to the data entry of interest. Note that if the guest directories and page tables have not previously been loaded into the processor's cache, they must be read from physical memory. The pseudo-physical addresses of those pages must therefore also be translated by hypervisor maps info physical addresses as previously described. The maps used to translate pseudo-physical to physical addresses reside in hypervisor space and are mapped into the hypervisor's virtual address space using still other page maps. Of will be noted that the pseudo-physical address does not use the full address width since the lower-order address bits are taken directly from the guest's virtual address; the remaining bits are used for, example, to identify read-only pages. The specific use of these bits is implementation dependent, but all implementations leave some of these bits undefined. One of these undefined bits is used in the present invention as described below. The major modification to the hypervisor's memory-management subsystem required to support checkpointing-is the implementation of an extension of the technique, described in U.S. Pat. No. 6,622,263, for ensuring that memory can be restored to its pre-rollback state following a fault. This involves the allocation of a bit, called a temporary-read-only bit, in each physical page address. This bit is set by the memory manager in each entry in the relevant directory whenever an operating system is invoked and again following the establishment of each operating system checkpoint. Any attempt to write to an address with the temporary-read-only bit set causes a trap to the memory manager. On response to such a trap, the memory manager first determines if the page being accessed is indeed read-only. If it is, the memory manager invokes the relevant page-fault handler. Of it is not read-only, the memory manager resets the temporary-read-only bit in the directory address in question, accesses the page table corresponding to that address and sets the temporary-read-only bit in each of its addresses except for the address of the data page being accessed. It then records the address of that page on a guest-OS-specific checkpoint address queue and, in the case of pre-image checkpointing, copies the page itself to a guest-OS-specific checkpoint data buffer. Optionally, temporary-read-only bit can also be used in the hypervisor's own virtual-to-physical map pages to enable the hypervisor to checkpoint its own state using the methodology described in U.S. Pat. No. 6,622,263. In this case, if a fault occurs in a guest OS context, the hypervisor rolls back the guest OS as described in the present invention. Of that should fail to correct the problem, or if a fault is encountered while the hypervisor itself is running, it then has the option of rolling back the entire system. 2) Device Emulator Subsystem The I/O subsystem in many hypervisors is implemented using virtual I/O processors (VIOPs). Preferably, the hypervisor is also capable of supporting dual VIOPs with each having interfaces to the same dual-ported controllers. This enables one VIOP to serve as a backup should the active VIOP sustain a non-recoverable fault (e.g., one of its attached physical controllers fails). Regardless of the specific I/O subsystem implementation, the hypervisor provides the guest operating systems with generic interfaces to each class of I/O device (e.g., disk, network, serial bus, parallel bus, display, etc.). Relatively minor modifications of these interfaces enable I/O operations to be handled correctly following a fault-induced rollback of the guest operating system that issued them. One of the major innovations of the invention is a means for preserving I/O buffers set up since the last checkpoint so that they can continue to be used following a fault. This makes it possible to recover from faults without having to restart in-process I/O operations after the system state has been rolled back to its last checkpointed state and without the need for separate physical I/O processors or specially modified I/O drivers. To make this possible, each of the I/O subsystem's device emulators establishes read- or write-buffers as the destination or source, respectively, of the data to be read from or written to the I/O device in question. On addition, it defines an I/O-request block that it places on a list of pending I/O requests (the “pending-I/O” list). Of the emulator serves as the interface to more than one physical device, it maintains separate lists for each such device. Two additional lists are maintained for each guest OS, one list for operations completed for that guest OS (the “completed-I/O” list) and one for operations the completion of which was acknowledged at the time of the last checkpoint (the “acknowledged-I/O” list). Finally, it also maintains a list of states associated with each device it emulates (the “device-state” list). There are various well-known procedures for managing such lists. For illustrative purposes, it will be assumed that the lists are structured as linked lists, with each item on the list containing the address of the previous item on the list, or an indication that it is at the head of the list, and the address of the next item on the list, or an indication that it is the last such item. (Device-specific pointers are used to indicate the addresses of the first and last items on the pending-I/O and device-state lists. Global pointers, accessible by all emulators, are used for the addresses of the last items on each guest OS's completed-I/O list. Each request block on the pending-I/O list contains the identification of the requestor as well as the details of request as extracted from the information submitted by the requestor, including the physical start address and the length of any buffer established for the I/O in the requestor's space. It also contains a pointer to the item on the device-state list indicating the state of the device of interest at the time the request was submitted. FIG. 2 is a flowchart showing the hypervisor's response to a request to write data to, or to read data from, an I/O device. Regardless of whether the request is for a read or a write, the hypervisor sets up a buffer of the appropriate length in its own virtual address space (step 201 ). Of the operation is for data to be read from an I/O device ( 202 ), the hypervisor defines a page map linking those virtual addresses to available physical addresses ( 203 ). If it is a write to an I/O device, the requestor has already generated the source data so the hypervisor defines a page map linking its buffer virtual addresses to the physical addresses containing the data ( 204 ). (The temporary-read-only bits in the hypervisor page maps are not set unless the state of the hypervisor itself is to be checkpointed.) If an attempt is made to write into one of the data pages reached through the guest's map for the first time since the last checkpoint (i.e., if some part of the page not actually part of the data buffer is written to for the first time) that page will be checkpointed in the normal way. After setting up the buffer, the hypervisor constructs the aforementioned request block ( 205 ) appending to it the starting virtual address of those buffers. It translates the I/O request into the appropriate driver-specific format using its own virtual addresses to define the source or destination of the data ( 203 ). Of the I/O command entails a driver state change ( 207 ), the emulator reflects that fact in a device-state block, links it to the device-state list and updates the end-of-list pointer ( 208 ). This status information is used to reestablish the driver's state should it be necessary to restart it, or a backup driver, following an I/O fault. The hypervisor then links the request block to the list of pending-I/O requests ( 209 ). While it is possible to release I/O requests between checkpoints and rely on higher-level communication protocols to accommodate the possibility that certain I/O events will need to be repeated or that others may be unexpectedly repeated, the higher checkpoint frequencies now practicable with state-of-the-art computer systems make it acceptable to delay releasing I/O requests until the next checkpoint takes place. Doing so relieves the higher-level protocols from having to account for such events. (Higher-level protocols must still be used, however, to resolve such ambiguities when an I/O-device or other failure causes pending I/Os to be resubmitted to a backup device either locally or on a remotely located computer.) Accordingly, step 209 stipulates placing the request block on the pending-I/O queue for that device, but delaying the release of the request until the next checkpoint. Similarly, when the requested I/O operation has been completed, the request block is moved to the completed-I/O list and the acknowledgement of that completion is passed on to the requesting guest at the time of the immediately following checkpoint. It should be noted, however, that disk read and write requests need not be synchronized with checkpoints. The technique described in U.S. Pat. No. 6,622,263 whereby disk access requests can be issued without waiting for a checkpoint is equally compatible with the current invention. The emulator's response to a message from the physical device indicating that a requested I/O has been completed is shown in FIG. 3 . It first compares the device-state address in the request block with the address of the head of the device-state list ( 301 ). If they agree ( 302 ), the device state recorded in the device-state block at the head of the list is the state that prevailed following the execution of the request. If they do not, the execution of the request changed the state of the device, so the oldest state on the list is no longer relevant. Accordingly, the oldest item on the list is delinked ( 303 ) and the pointer to the head of the list updated. The emulator then delinks the request block from its list of pending I/Os and links it to the completed-I/O list of the guest OS that generated the request ( 304 ). 3) Checkpointing and Recovery Subsystem FIG. 4 shows a flowchart illustrating the checkpointing procedure. The first step in the procedure (step 401 ) is for the hypervisor to force a context switch through which all processors running the guest OS to be checkpointed switch to the hypervisor state. The mechanism for doing this is implementation dependent but typically involves an interrupt or trap that is recognized by the relevant processors. The trigger for forcing this context switch is usually determined by the elapsed time since the last checkpoint, but other triggers, such as blockage on certain I/O events can be used in addition to the normal time-based triggers. Following the context switch, during which the internal state of each affected processor is dumped on the relevant process queue, all modified cache blocks are either flushed out to main memory or otherwise captured (see below). Depending on whether pre- or post-image checkpointing is used ( 402 ), the hypervisor then either simply resets the pointers into the checkpoint address and pre-image data page queues ( 403 ) or else copies the pages identified by the checkpointed addresses into shadow memory ( 404 ). As demonstrated in U.S. Pat. No. 6,622,263, this copying can optionally be done in background mode after normal processing resumes. If post-image checkpointing is being implemented, the processor caches do not need to be flushed if the processor implements any of the standard cache-coherency protocols that ensure that the most recently modified cache line is always sourced whenever it is accessed, regardless of where it physically resides. On this case, when each modified page is copied to shadow memory, any modified cache line in that page will be copied, even if it has not yet been moved back to main memory. Again depending on the specific processor implementation, it may be necessary to invalidate, or at least set the temporary-read-only bits, in the processor-resident virtual-to-physical address-translation buffers, usually called the translation-look-aside buffers (TLBs), at each checkpoint. This ensures that the first attempt to write to a page following the checkpoint will still result in the previously described trap even if that same page had an entry in the TLB prior to that checkpoint. Once the guest OS's state has thus been checkpointed, the hypervisor discards the list of acknowledged I/O operations ( 405 ) since the fact that these operations have been completed is now part of the guest's checkpointed state. It then sets up the environment needed to return the context to that of the guest operating system. This guest OS may or may not be given the same processing resources that it had when it was checkpointed, however, since the hypervisor can reallocate resources whenever the occasion demands. To set up the environment, the hypervisor scans the completed-I/O list associated with the guest OS to be invoked ( 406 ) and, if there are any request blocks on that list ( 407 ), examines the first such request ( 408 ). If it is a read request, the hypervisor then determines if the request involves any partially used pages ( 409 ). If it does, it copies the portions of those pages that correspond to the buffered data from the hypervisor's buffer pages to the corresponding locations in the guest's read buffer ( 410 ). Optionally, the hypervisor can copy the non-buffer portion of the corresponding guest page into the hypervisor's buffer page and then remap that page as the new guest page. This may represent a small performance improvement if the data buffer contents of the page in question exceed half the size of the page. On any case, the hypervisor then remaps all full buffer pages from its own space into the guest's space ( 411 ), thereby effectively filling the guest's read buffer with the requested information. If the request was for a write operation, the hypervisor simply unmaps the source pages from its own space ( 412 ), freeing up those virtual addresses for other uses. The source pages remain mapped into the guest OS's space. For both read and write operations, following the remapping of the data buffers, the hypervisor informs the requesting OS that the operation has been completed and moves the request block from the completed-I/O lost to the acknowledged-I/O list ( 413 ). This latter list is retained until the next checkpoint since the guest OS will have to be informed of the fact that the operation has been completed should it be roiled back before that information is part of its checkpointed state. The method for acknowledging the completion of the operation to the guest OS is implementation and device dependent, but typically involves an interrupt or trap directed to the guest OS. Once all I/O operations that were completed prior to the last checkpoint have been dealt with, the hypervisor releases all pending I/O requests (i.e., all those I/O requests generated since the last checkpoint) to the relevant device emulators ( 414 ), sets the temporary-read-only bits in the guest's page directory and institutes a context switch back the guest OS ( 415 ). The recovery procedure following a fault is shown in FIG. 5 . If pre-image checkpointing is being implemented ( 501 ), the hypervisor copies the checkpointed memory pages from checkpoint memory back to the locations indicated by the checkpointed addresses ( 502 ). If post-image checkpointing is used instead, it switches to the shadow memory ( 503 ). Depending on the specifics of the checkpointing scheme being implemented, it may simply remap the guest OS's pages to their shadow locations or, in the case of remote checkpointing, it may reallocate all resources associated with the guest OS to the backup computer. Also, depending on the implementation and the nature of the fault, it may reestablish the abandoned pages in the primary memory as the new shadow memory. After thus returning the guest OS back to its last checkpointed state, the hypervisor then relays acknowledgements for all I/O operations that were completed at the time of that checkpoint ( 504 ) and those that have been completed since that time ( 505 ). The latter acknowledgements are then moved to the acknowledged I/O list. At this point, the guest OS is ready to resume operation ( 503 ). If an I/O device fails, the device emulator resets that device to the state listed in the block at the head of the device-state list, thereby returning it to the state that prevailed at the time the request at the head of its pending-I/O request list was submitted. If then resubmits that request, and, in turn, the rest of the requests on the pending-I/O queue, if the device in question has a backup, either locally or, if remote checkpointing is being used, on some other computer (e.g., if the hypervisor supports dual VIOPs), the I/O operations can be restarted on the backup device. If the device is located on a different computer from the one running the guest OS in question, the device-state and pending-I/O request queues must also be sent to the backup computer whenever a new I/O request is submitted by that guest OS. These same modifications also make it possible to recover from a fault in the VIOP itself, either by restarting the VIOP (assuming the fault does not permanently disable an attached controller) or by switching to the dual VIOP and, in either event, returning the device emulators to the appropriate state as before and reissuing all pending I/O requests. In this case, higher-level protocols must be relied upon to cope with possibly repeated requests. As previously noted, the invention disclosed here is compatible with that disclosed in U.S. Pat. No. 6,622,263 enabling the hypervisor itself also to be checkpointed. If this is done and the entire system, as opposed to a single guest OS, is rolled back, some I/O operations may be interrupted and will have to be restarted as described in that disclosure.

While system-directed checkpointing can be implemented in various ways, for example by adding checkpointing support in the memory controller or in the operating system in otherwise standard computers, implementation at the hypervisor level enables the necessary state information to be captured efficiently while providing a number of ancillary advantages over those prior-art methods. This disclosure details procedures for realizing those advantages through relatively minor modifications to normal hypervisor operations. Specifically, by capturing state information in a guest-operating-system-specific manner, any guest operating system can be rolled back independently and resumed without losing either program or input/output (I/O) continuity and without affecting the operation of the other operating systems or their associated applications supported by the same hypervisor. Similarly, by managing I/O queues as described herein, rollback can be accomplished without requiring I/O operations to be repeated and I/O device failures can be circumvented without losing any I/O data in the process.

This application claims the benefit of Provisional application Ser. No. 60/071,754, filed Jan. 16, 1998. BACKGROUND OF THE INVENTION This invention relates to a non-destructive testing method for determining the texture of materials using ultrasonics. The word “texture” designates direction-dependent properties of materials. One direction-dependent property of particular interest is elastic anisotropy in polycrystalline materials that results from the non-random distribution of the crystallographic orientations of single grains. Crystallographic texture is described by an orientation distribution function (ODF). Information on ODF is usually obtained from pole figure X-ray diffraction and typically consists of thousands of diffraction data points. Conventional texture analysis of materials normally involves destructive testing. A small sample is cut off from a material and tested in a laboratory. In some cases, especially in production control, it is not necessary to determine the “whole” texture. In this case, it is possible to use a low-resolution texture analysis method which relies upon a strict correlation between some material physical properties such as, for example, elastic or magnetic properties, and crystallographic texture. By restricting the texture analysis to a low-resolution technique, it is possible to perform texture analysis in a non-destructive way that offers the possibility of on-line qualitv control inspection. Three different techniques for low-resolution texture analysis are known. A first technique consists of taking X-ray measurements of a material under test. A device, called an “On-Line Texture Analyzer”, designed and used for this purpose, irradiates a sample with an incident beam containing a continuous spectrum of wavelengths such as, for example, the X-ray bremsstrahlung spectrum. Characteristic pole-intensities of the sample are measured by energy-dispersive detectors detecting the X-ray bremsstrahlung spectrum transmitted through the sample material. However, this technique is limited to relatively small thicknesses of material. This limitation is due to strong X-ray attenuation and dispersion inside the polycrystalline material, and strict requirements for positioning of the X-ray source and detectors with respect to the texture of the material sample. A second technique consists of electromagnetic Barkhausen noise and dynamic magnetostriction measurements. However, this technique is limited to materials having strong magnetic anisotropy. A third technique is based on the measurement of a material's vibrational properties, such as an ultrasound velocity, which are known to be correlated with the material texture. Ultrasound velocity measurements have advantages over the first two techniques in that samples to be tested are not limited in thickness, and materials without strong magnetic anisotropy may be analyzed. A prior art ultrasonic method for low-resolution texture analysis of single-phase polycrystalline materials such as, for example, low-alloyed aluminum having a cubic structure and orthorhombic texture is depicted in FIG. 1 . This technique employs a pulse-echo method to determine three ultrasound absolute propagation velocities (with respect to the specimen coordinate system) propagating in the rolling, transverse, and normal directions. A single, short-duration, high-frequency ultrasound pulse 10 , generated by an ultrasonic transducer 12 , advances into a specimen 14 which has flat, parallel surfaces. Multiple reflections of ultrasound inside the specimen 14 results. A series of consecutive echos 16 (see FIG. 1A) with gradually decreasing amplitudes are generated. The echos 16 are received by the transducer 12 for calculation of the propagation velocity. The propagation velocity may be calculated using measurements of ultrasound round-trip path length and ultrasound round-trip time-of-flight. The round-trip path length may be determined as a doubled specimen thickness (L in FIG. 1) precisely measured in the direction of ultrasound propagation. The ultrasound time-of-flight may be measured as a time interval or period 17 between the leading edges of two consecutive echos 16 . The absolute propagation velocities, calculated as a ratio of round-trip path length to time-of-flight, are usually used to determine the elastic constants (fourth-order expansion coefficients of the elasticity matrix) which characterize the texture of the specimen 14 . However, the accuracy of time-of-flight measurements may vary substantially depending on a number of factors such as: ultrasound pulse frequency spectrum; pulse rise time, length and shape; transducer-to-specimen positioning and coupling; and frequency band, resolution and accuracy of the electronic receiving system. The accuracy of the time-of-flight measurements is especially critical for materials having a low elastic anisotropy factor such as, for example, low-alloyed aluminum. In order to obtain acceptable measurement accuracy, out-of-line laboratory measurements may be required. The prior art ultrasonic method for texture characterization may not be suitable for on-line texture analysis. SUMMARY OF THE INVENTION A method of on-line ultrasonic texture characterization of a sputtering target is provided. Texture characterization may be accomplished through analysis of an ultrasonic backscattering signal amplitude distribution. A broad-band, focused ultrasonic transducer generates a megacycle center frequency ultrasonic pulse having a wavelength in the range of the average grain size (in the direction of ultrasound propagation) of a sputtering target specimen. The ultrasonic pulse is introduced into the specimen at an incident angle normal to the surface of the specimen. Due to interaction of the ultrasonic pulse with the texture of the specimen, backscattering echoes are generated in a portion of the specimen located within the transducer focal zone. The backscatter region extends at least one grain layer beneath the specimen surface to a depth of several grain layers in thickness. The backscattering echoes propagate back to the transducer where the echoes are converted by the transducer into an electrical signal which is processed by a broad-band acquisition system. A maximum amplitude value of the backscattering signal is extracted from the processed data and stored in a memory of the acquisition system for future data analysis. Data analysis is performed using data graphical representation in the form of a histogram of “occurrences versus amplitude” where the amplitude is plotted along the x axis while the occurrences (counts for certain amplitude values) are plotted along the y axis. The histogram is compared with histograms for reference standards having known preferred crystallographic and grain orientation, grain size, and chemical composition. Therefore, it is an object of the invention to provide a method of ultrasonic on-line texture characterization. It is a further object of the invention to provide a method of on-line texture characterization including the step of generating an ultrasonic pulse with a wavelength in the range of the average grain size of a specimen material in the direction of ultrasound propagation. It is yet another object of the invention to provide a method of ultrasonic on-line texture characterization including the step of detecting an ultrasonic backscattering signal generated by interaction of an initial ultrasonic pulse with specimen material texture. A still further object of the invention is to provide a method of ultrasonic on-line texture characterization including the step of plotting the backscattering signal amplitude in the form of a histogram of “occurrences versus amplitude”, and comparing the histogram with similar histograms for materials having known preferred crystallographic and grain orientation, grain size, and chemical composition. Other objects of the invention will be apparent from the following description the accompanying drawings and the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a prior art method of ultrasonic texture analysis; FIG. 1A is a schematic diagram showing the ultrasound echoes obtained by the prior art method shown in FIG. 1; FIG. 2 is a schematic diagram of a method of ultrasonic on-line texture characterization in accordance with the invention: FIG. 3 is an enlarged schematic view of the backscattering region of the sputtering target of FIG. 2 showing backscattering echoes propagating from grain boundaries; FIG. 4 is a histogram of “occurrences versus amplitude” obtained according to the method of the invention for a relatively isotropic “random” texture; FIG. 5 is an X-ray diffraction pole-figure proof for the data shown in FIG. 4; FIG. 6 is a histogram of “occurrences versus amplitude” obtained according to the method of the invention for an anisotropic material having a strong <100> preferred crystallographic orientation: FIG. 7 presents the X-ray diffraction pole-figure proof for the data shown in FIG. 6; FIG. 8 is a histogram of “occurrences versus amplitude” obtained in accordance with the method of the invention for a <100> single crystal; FIG. 9 is a plot of normalized intensity versus tilt angle alpha, <200> azimuthally averaged, for the sputtering target of FIGS. 4 and 5; FIG. 10 is a plot of normalized intensity versus tilt angle alpha, <200> azimuthally averaged, for the sputtering target of FIGS. 6 and 7; FIG. 11 is a plot of normalized intensity versus tilt angle alpha, <200> azimuthally averaged, for the <100> single crystal of FIG. 8; and FIG. 12 shows the correlation between ultrasonic backscattering amplitude and degree of <200> preferred orientation for the sputtering targets and single crystal of FIGS. 4 - 11 . DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Turning to FIGS. 2 and 3, there may be seen schematic diagrams illustrating the method of the instant invention. A single, short-duration, megahertz frequency range ultrasonic pulse 20 , is generated by a focused ultrasonic transducer 22 . The pulse 20 is directed at a material 24 such that the angle of incidence of the pulse 20 is normal to the surface 26 of the material 24 . A backscattering signal 28 originates in a backscattering region 32 . The backscattering region 32 is located inside a transducer focal zone 34 and has a depth extending from at least one grain layer beneath the surface 26 to a depth of several grain layers. Backscattering occurs as a result of acoustic, impedance (i.e., ultrasound velocity) mismatch at grain boundaries of adjacent grains. Due to a limited number of grain boundaries along the ultrasound path inside the backscattering region 32 , the backscattering signal 28 experiences less signal volume averaging than the reflected ultrasonic signal of the prior art (FIG. 1 ). At a nearly resonant mode of ultrasound propagation (i.e., the ultrasound wavelength is in the range of average grain size), the statistics of identical wave phase shift at the grain boundaries inside the backscattering region 32 will depend on the degree of preferred crystallographic orientation. The number of identical wave phase shifts increases with increasing degree of preferred crystallographic orientation. The increase in the number of identical phase shift occurrences is detected as an increase in the number of counts for identical backscattering amplitudes. As a result, a histogram of “occurrences versus amplitude” tends to shrink in width and stretch in height with increasing kurtosis of the histogram (FIG. 6 ). In contrast, for materials having more isotropic texture, the histogram of backscattering signal amplitude is broader and shorter due to more random phase shift distribution (FIG. 4 ). Turning now to FIGS. 4 and 6, there may be seen histograms of backscattering signal amplitudes obtained in accordance with the method of the invention for two different material specimens. The first material specimen used to produce the histogram given in FIG. 4 is of an isotropic random crystallographic orientation. The FIG. 6 histogram results from ultrasonic analysis, in accordance with the invention, of a strong <100> preferred crystallographic orientation. In both cases, the specimen materials comprise aluminum-0.5 weight percent copper alloy having equivalent-axed grain texture (crystallographic orientation) and grain sizes in the range of 0.26 millimeter to 0.38 millimeter. The ultrasonic transducer 22 used to obtain the histograms is a 15 megahertz spherical focalization transducer. The region for backscattering signal monitoring is specified by focusing the transducer on a flat bottom hole of 0.1 millimeter diameter located at a distance of two millimeters under the surface of the specimen material. Comparing FIG. 6 with FIG. 4, it may be seen that the less textured material of FIG. 6 exhibits a narrower and taller or more elongated histogram of backscattering signal amplitude than the material having more random texture as shown in FIG. 4 . The X-ray diffraction pole-figures of FIGS. 5 and 7 confirm the findings of the observed differences in the preferred crystallographic orientations of the two specimen-materials. It should be noted that the effects of isolated, minute flaws on the histograms can be discarded or ignored if the total number of data points acquired exceeds the number of flaw-related data points by three to five orders of magnitude. By way of comparison, the histogram for a single crystal of Al-0.5 wt % Cu alloy having a crystallographic orientation of <100> is shown in FIG. 8 . The histogram of FIG. 8 was also obtained using a 15 megahertz spherical focalization transducer focused on a flat bottom hole of 0.1 millimeter diameter located at a distance of two millimeters beneath the surface of the crystal. The histogram shows an amplitude variation for the single crystal of about 4.7%, and a peak of about 2,716 occurrences. Graphs of normalized intensity versus tilt angle alpha in degrees for a <200> azimuthally averaged X-ray beam for each of the samples of FIGS. 4, 6 , and 8 , may be seen in FIGS. 9, 10 , and 11 , respectively. FIG. 12 shows a plot of the normalized ultrasonic backscattering amplitudes versus the degree of preferred <200> intensity normalized (azimuthally averaged) for each of the three sample specimens. The plot in FIG. 12 shows that there is a linear correlation between the results obtained from the instant texture characterization analysis by ultrasonic backscattering means and a conventional X-ray diffraction pole-figure analysis method. For example, point 202 in FIG. 12 shows the normalized intensities for both the ultrasonic detection means (y-axis) and x-ray diffraction methods (x-axis) as applied to the isotropic random texture specimen with point 204 representing the x, y coordinate intensities found for the strong <100> preferred orientation sample. Point 206 represents the ultrasonic and x-ray diffraction intensities for the single crystal material tested. Thus, the instant method of ultrasonic on-line texture characterization analysis yields good results when compared with standard out-of-line measurement techniques since there is a clear linear relationship between the two methods. It is to be noted that the ultrasonic pulse to be applied to the sputter target may be applied through a fluid medium such as air or water. Presently, it is preferred to place the sample in a water immersion tank to thereby apply the pulse through water. Typically, the transducer will be located at normal incidence to the specimen surface. The pulse or burst of MHz-range frequency electrical signal is generated by an electronic pulser tuned to the frequency range of the ultrasonic transducer (11-18.5 MHz). This signal is converted by the transducer into an ultrasound pulse. The ultrasound pulse propagates through the water (which is a couplant) at a normal incidence to the specimen surface. As a result of the interaction of the ultrasonic pulse with the exposed volume of the specimen (approximately 5 mm deep into the specimen measured from the top surface) part of the ultrasonic energy is scattered back to the transducer in the form of an echo. The exposed area is situated inside the transducer focal zone (−6 dB). When the echo arrives, the transducer electronically switches from an electronic transmitter to a gated electronic receiver. The echo is received at the transducer about 60 microseconds after the pulse is sent. The returned RF signal (the ultrasonic echo) is captured inside the gate of a low noise gated preamplifier. The pre-amplified RF echo is passed to the low noise linear amplifier. The echo acquisition system includes: the low noise gated preamplifier; the low noise linear amplifier with a set of calibrated attenuators; and a 12-bit ADC (2,44 mV/bit) and a PC equipped with a printer. The linearly amplified analog RF echo signal is digitized by the 12-bit ADC (2, 44 mV/bit) and passed in digital form to the PC. The maximum value of the digitized RF signal is stored in the memory of the PC software. This maximum value is used for texture analysis. The texture analysis device shown in FIG. 2 uses an immersion tank filled with DI water. It is equipped with a mechanical X-Y scanner, electronic pulser-receiver instrument and transducer assembly mechanically attached to the X-Y scanner. The mechanical X-Y scanner is controlled by a PC based electronic controller. The X-Y scanning unit performs a meander-like stepwise motion with short steps in the X direction and longer steps in the Y direction. Data acquisition steps in both X and Y directions were chosen to equal 0.8 mm to provide a detection of 0.1 mm flat bottom hole at detection level (9-6 dB) without exposure area overlapping. The preferred transducer is sold by Panametrics, USA under the model V 319 designation. This is a high resolution piezoelectric transducer having a focalization distance of 51 mm and 12.5 mm in diameter with a center frequency of 15 MHz and 7.2 MHz bandwidth (-6 dB). In detecting the backscatter echo, software available from Structural Diagnostics, Inc. under the designation SDI-5311 can be used. Before testing, the specimen surface should be prepared via diamond cutting or the like. Usually, the texture characterization is performed for the entire area of the target, usually 7.5 in.×7.5 in. For texture analysis, about 50,000-500,000 raw data points are analyzed. The velocity of the ultrasonic pulses propagating from the target is commonly on the order of about 6.29-6.35×10 −1 cm/microsecond. While the method herein described, and the form of apparatus for carrying this method into effect, constitutes a preferred embodiment of this invention, it is to be understood that the invention is not limited to this precise method and form of apparatus, and that changes may be made in either without departing from the scope of the invention, which is defined in the appended claims.

A sputtering target ( 24 ) under test is irradiated with an ultrasonic pulse ( 20 ). The ultrasonic pulse ( 20 ) has a wavelength in the sputtering target ( 24 ) in the range of the average grain size for the target ( 24 ) under test. Backscattering echoes ( 28 ) are produced by the interaction of the pulse ( 20 ) with grain boundaries in the target ( 24 ) under test. The backscattering echoes ( 28 ) are detected and a representative electrical signal is generated. The number of occurrences of the backscattering echoes ( 28 ) having amplitudes within predetermined ranges are determined. A histogram of the number of occurrences versus amplitude is plotted. The histogram for the target ( 24 ) under test is compared with reference histograms for sputtering targets having known crystallographic orientations to determine the texture of the target ( 24 ) under test.

FIELD OF THE INVENTION [0001] This invention relates to electronic displays and an improved switching control circuit based on diodes for the control of the circuit. BACKGROUND AND PROBLEM TO BE SOLVED [0002] In an electronic display, a material, called the display medium, changes its optical state, e.g. reflectivity, transmission or light emission, in response to an electrical signal such as a voltage or an injected current. Particularly widely used are liquid crystal displays (LCDs), which change either the polarization of light or the reflectivity for light under the influence of voltage. Typically the display architecture comprises a transparent front substrate coated with a transparent conductive electrode, e.g. Indium Tin Oxide (ITO), which may be patterned or unpatterned (the front plane), a back plane comprising electrodes which may optionally be transparent and an optional substrate which may also optionally be transparent, and the display medium place between the front and back plane. The control of the optical state of the display results from the application of a voltage between the front and back plane electrodes which creates an electric field across the display medium or injects a current into the medium. The display may be divided into segments or, for more complicated information, into so-called pixels organised into a matrix of rows and columns. [0003] Some display media display image retention without being actively addressed, i.e. once an image is written to a display based on such a medium, no further power is needed to maintain the image, at least for a significant amount of time. Such displays are commonly called bi-stable, even though many such displays are not strictly speaking truly bi-stable (having two stable states of equal energy), and this terminology will be applied herein as well. [0004] Two types of bi-stable displays that have generated significant interest for “electronic paper” applications are electrochromic displays, such as reported and provided by NTera Inc. (www.ntera.com), and electrophoretic displays such as are reported and provided by E Ink Inc. (www.eink.com) and Sipix (www.sipix.com). These displays show optical properties that in many ways are similar to ink on paper. However, these displays generally require an active matrix structure (an active electronic circuit controlling the electronic and optical state for each pixel) in order to display detailed information, as they are not addressable by passive matrix techniques and/or the response times are too slow for passive matrix line by line addressing. [0005] Active matrix circuits may be constructed on the basis of thin film transistors (TFTs), which are three terminal devices, or two terminal devices such as rectifying diodes and MIM diodes. TFTs have become the standard technique for LCDs. In a TFT display, patterning is all done on the back plane of the display, with row and column lines connected to gate and source electrodes; the front plane electrode is typically unpatterned throughout the active area of the display. This has the advantage of reducing the requirements for alignment of front and back planes during assembly, which is especially important for displays which are made using printing technology and/or flexible substrates, e.g. using organic semiconductors for the TFTs (see, for example, www.plasticlogic.com). On the other hand, TFTs require very fine patterning steps and excellent semiconductor characteristics, especially charge carrier mobility, to perform adequately, and both issues become difficult when using printing technology and organic semiconductors. [0006] A number of diode-based active matrix back plane structures have been disclosed in the past and some have also been used commercially. Two structures are the diode ring and the back-to-back diode configuration, as seen in FIG. 1 . [0007] The display medium is in series with the diode circuit; the diode circuit and the display medium are placed between the row and column electrodes. [0008] Another diode circuit design is called the two-diode switch, and the circuit is illustrated in FIG. 2 . This circuit configuration requires both a patterned front plane electrode structure and two select lines for each row of pixels. Patent application WO 2004/066410 discloses diode based circuits for active matrix back planes using single diode and back-to-back configurations, where the diodes are thin film diodes made using organic semiconductors ( FIG. 3 ). Two potential advantages of organic diodes over organic TFTs are less stringent requirements on charge carrier mobility and less stringent requirements on resolution due to the vertical instead of horizontal structure of the charge conducting layer. These two advantages can be especially significant for cost-efficient, high-throughput printing based manufacturing of active matrix back planes, as the resolution achievable with standard printing methods is limited. As in FIGS. 1 and 2 , a patterned front plane electrode is used. [0009] Metal-insulator-metal diode (M-I-M) diodes differ from rectifying diodes in that the current-voltage curves are symmetrical. MIM diodes have also been used to form active matrix back planes for displays; and example structure is shown in FIG. 4 . Note that also here the display medium (here a liquid crystal) is in series with the diode element in between row and column electrodes, i.e. the front plane electrode must be structured. [0010] Active matrix back planes based on solution processible MIM diodes have been disclosed in patent application disclosure WO 2004/051750 and in U.S. Pat. No. 6,380,922. In the former no description of a circuit or reduction to practice is given. In the latter, printed MIM diodes based on inorganic metal oxides are claimed for use in active matrix displays, preferably electrophoretic displays. An unpatterned front plane electrode is used in the proposed circuit, which can drive a single pixel, but no disclosure is made how an entire matrix of rows and columns could effectively be driven. [0011] U.S. Pat. No. 6,980,196 discloses an electronic display where the display medium is particle based, e.g. electrophoretic, and controlled by an active matrix which may comprise printable nonlinear diode elements, the intention being the fabrication of a printable active matrix display. The display medium is placed in series with the nonlinear device between row and column electrodes, i.e. the disclosure requires patterned front plane electrodes. However, as mentioned above, having structured elements on both the front and back plane create additional alignment difficulty, especially if printing and lamination processes are used for display fabrication and assembly. Furthermore, some display media, e.g. electrophoretic and polymer-dispersed liquid crystal media, are frequently commercially available primarily as front plane laminates with the active display medium already laminated onto an unpatterned front plane. SUMMARY OF THE INVENTION [0012] Therefore an object of the invention is to disclose a diode based back plane circuit that can drive a display medium, especially a bistable display medium, effectively in a matrix configuration such that row and column address lines are both on the back plane and the front plane is essentially unpatterned in the active display area. Furthermore, the driving circuit matrix should be able to drive a full matrix display with good contrast between optical states, and with the highest possible power efficiency. [0013] The invention discloses diode based backplane circuits that are able to drive a display medium, especially a bi-stable display medium, in an active matrix mode with a minimum of additional voltage and leakage current, without the need for a patterned front plane, and with optical performance comparable to directly driven displays and TFT active matrix displays [0014] In one embodiment, the diode active matrix back plane disclosed herein comprises a matrix of row and column address lines on the back plane, with two rectifying diodes in series between the row and column lines, plus a load impedance in series with the diodes and disposed between the second diode and the row line. The display medium is located between the backplane and an unstructured front plane electrode structure, and the back pixel electrode of the display medium is connected to the diode circuit between the two diodes. The back plane architecture and the addressing scheme used are suitable for bi-stable display media possessing a short circuit memory (i.e. able to maintain an image even when the front and back electrodes are connected and at the same potential) without a patterned front plane. All the pixel capacitors share a common front electrode [0015] In another embodiment of the invention, the display pixel electrode is still connected to the circuit between the two diodes, but the load resistor is made unnecessary, by choosing a diode-diode configuration in which the diodes have different forward resistances at chosen current values. [0016] In a further embodiment of the invention, the pixel electrode is connected to the circuit between a source lead at either a driving voltage or ground and two diodes which are connected to the row and column lines. Depending on the source voltage and the direction of the diodes, this circuit functions like an AND or OR gate to drive the pixels. This circuit is also able to drive a bistable display with an unpatterned front plane. [0017] According to a first aspect of the present invention there is provided a display comprising a plurality of row electrodes; a plurality of column electrodes; a plurality of pixels, each pixel of said plurality of pixels being assigned to a crossing of one row electrode and one column electrode; a plurality of pixel electrodes each assigned to one pixel; a plurality of pixel driving circuits for controlling the state of said plurality of pixels; and a display medium; wherein each of the driving circuits comprises a load impedance; a first diode connected between one row electrode and said pixel electrode; and a second diode connected between one column electrode and said pixel electrode, and said at least one row electrode, said at least one column electrode and said pixel electrode are on the same side of the display medium. [0028] According to a second aspect of the present invention there is provided a circuit for driving a display, the display comprising a plurality of row electrodes; a plurality of column electrodes; a plurality of pixels, each pixel of said plurality of pixels being assigned to a crossing of one row electrode and one column electrode; a plurality of pixel electrodes each assigned to one pixel; wherein said driving circuit comprises a load impedance; a first diode connected between one row electrode and said pixel electrode; and a second diode connected between one column electrode and said pixel electrode. DESCRIPTION OF THE DRAWINGS [0036] FIGS. 1-4 show examples of the known state of the art for diode based display driving circuits, which require a patterned front plane; [0037] FIG. 5 shows the unit circuit for one pixel of one embodiment of the invention; [0038] FIG. 6 demonstrates graphically the relationships between resistances under different driving conditions in one embodiment of the invention; [0039] FIG. 7 shows the unit circuit for one pixel of another embodiment of the invention; [0040] FIG. 8 shows the unit circuit for one pixel of further embodiment of the invention; [0041] FIG. 9 shows an example of a backplane circuit for one embodiment of the invention; [0042] FIG. 10 shows an embodiment of the invention in which the driving circuit is disposed laterally to the display pixel electrode; [0043] FIG. 11 show a first embodiment of the invention in which the driving circuit is disposed vertically to the display pixel electrode; [0044] FIG. 12 show a second embodiment of the invention in which the driving circuit is disposed vertically to the display pixel electrode; and [0045] FIG. 13 show an example of a device in which the invention can be applied. DETAILED DESCRIPTION OF THE INVENTION [0046] Four embodiments of the diode based matrix driving circuit are disclosed herein. In the description of these embodiments the following terminology will be used: Row==Row Col==Column Pixel==Pixel [0047] R==loading resistor RRR==diode reverse resistance C==Pixel capacitance against front plane Vs==source voltage Vd==diode threshold voltage [0048] In one embodiment, a unit cell of which is shown in FIG. 5 , the unit cell 10 (pixel) of the diode active matrix back plane disclosed herein comprises a connection to row address lines 11 and column address lines 12 on the back plane, with two rectifying diodes 13 and 14 in series between the row and column lines, plus a load impedance 15 in series with the diodes and disposed between the second diode and the row line. The display medium is located between the backplane and an unstructured front plane electrode structure, and the pixel back electrode 16 of the display medium is connected to the diode circuit between the two diodes. [0049] The relationship of impedances in a single pixel element is sketched in FIG. 6 . In forward bias the resistance Rl of the load resistor 15 is dominant wherein the forward bias resistance Rf of the diodes 13 , 14 is negligible and the voltage drop is essentially over this load resistor 15 . In reverse bias the resistances Rr of the diodes 13 , 14 are dominant wherein the resistance Rl of the load resistor 15 is negligible. [0050] The following truth table describes the state of the pixel back electrode as a function of the voltages on the row 11 and column address line 12 to which it is connected via the circuit according to the invention. If the voltage in the row address line 11 (row voltage) is at 0 that row is selected and the state of the pixel can be changed. A voltage of 0 at the column address line 12 (column voltage) will cause a charged pixel to discharge at a time defined by the load resistance and the pixel capacitance, while an uncharged pixel remains uncharged. A column voltage of Vs will not change the state of a pixel electrode at Vs-Vd but will charge an uncharged pixel to Vs. If the row voltage is Vs (unselect), then a column voltage of 0 will in principle cause the pixel to charge or discharge to Vs/2 but due to the extremely high reverse bias resistance of the diodes this process will be too slow to observe and the pixel will remain in the same state. If the row and column are both at Vs, then the pixel electrode will be at Vs-Vd. [0000] Pixel Row Column RC −> 0, 0 0 0 Vs − Vd 0 Vs RRRC −> Vs/2 Vs 0 Vs − Vd Vs Vs [0051] Based on the above truth table, it can be seen that for the example of a bistable display medium with short circuit memory (i.e. a medium for which the optical state does not change if the front and back electrodes are at the same potential) with the front plane at Vs-Vd, the situation in which both row voltage and column voltage are at 0 will force the pixel to a state with a potential of −(Vs-Vd), while for the other combinations the state of the pixel will be unchanged. [0052] In addition to enabling the control of the pixel state, the loading impedance also enables to lower the current consumption of the diode active matrix backplane. This is due to the current limiting nature of the loading impedance. There are a number of preferential embodiments of this embodiment of the invention disclosed herein. It is advantageous if the load impedance is at least 100 kOhm and especially preferred if the load impedance is over 1 MOhm. The value of the loading impedance must be selected such that Rf<Rl<Rr, where Rf is the forward impedance of the diodes, Rl the load impedance of the pixel and Rr is the reverse impedance of the diodes. [0053] The reverse bias current of the diodes is advantageously less than 1 μA per pixel, preferentially less than 1 nA. The rectification ratio of the diodes is advantageously larger than 100, and preferentially larger than 1000. [0054] In another embodiment of the invention, the load resistor is replaced by a diode-diode configuration in which the diodes have different forward resistances at chosen current values. This can be taken into account with the driving wave forms by setting the pixel capacitors to the same voltage as the front plane. [0055] There are other possible alternatives to realise a pixel driving scheme without structured front plane. In a further embodiment of the invention the driving scheme is realised with diode logic gated with either AND or OR structure. [0056] A unit circuit for the AND configuration is shown in FIG. 7 and the truth table is analysed similarly to the embodiment above. The unit cell 20 of the diode active matrix back plane comprises a connection to row and column address lines 21 and 22 and a source voltage Vs 23 on the back plane. Between the source and the row and column electrodes are disposed diodes 24 and 25 and load resistor 26 . The back pixel electrode 27 is disposed between the load resistor and the diodes. In the AND configuration the pixel electrode is discharged to 0 unless both the row and column are at Vs. Truth Table for AND [0057] [0000] Pixel Row Column RC −> 0 0 0 RC −> 0 0 Vs RC −> 0 Vs 0 Vs − Vd Vs Vs [0058] A unit circuit for the OR configuration is shown in FIG. 8 and the truth table is analysed similarly to the embodiment above. The unit cell 30 of the diode active matrix back plane comprises a connection to row and column address lines 31 and 32 and to a ground connection 33 on the back plane. Between the ground and the row and column electrodes are disposed diodes 24 and 25 and load resistor 26 . The back pixel electrode 37 is disposed between the load resistor and the diodes. In the OR configuration the pixel electrode is at Vs if either the row is column are at Vs and 0 if both are at 0. Truth Table for OR [0059] [0000] Pixel Row Column RC −> 0 0 0 Vs − Vd 0 Vs Vs − Vd Vs 0 Vs − Vd Vs Vs [0060] A matrix backplane 40 can be constructed by connecting row electrodes and column electrodes together as described in FIG. 9 for the first embodiment described. Row electrodes 41 - 43 and column electrodes 44 - 46 are disposed on the back plane of a display, with unit circuits 47 disposed between the row and column electrodes as disclosed above. [0061] The embodiments described above can drive a display under assumption that the display medium is bistable and has a short circuit memory, i.e. the medium does not change its optical state if there is no potential difference between the front and back plane electrodes. [0062] A display driving scheme according to the invention is based on the fact that if there is no potential difference between the pixel electrode and the front plane the pixel remains optically unchanged. This enables possibility to construct a circuit and driving scheme in such a way that once a row is unselected all pixel electrodes in that row are in the same potential with front plane. [0063] The following example illustrates a driving scheme for a bistable display according to FIG. 9 . [0064] The front plane potential is initially set to Vs-Vd. Setting a row to Vs results in a situation where all the pixels at that row will be set to Vs-Vd. As this is the same potential as the front plane the optical state of the pixel will remain unchanged. However if the row is selected by setting it to 0, which is a different potential compared to the front plane, it is possible to determine the pixel voltage by controlling the state of the column electrodes. If a column is set to Vs the pixel is unchanged, since the voltage in pixel electrode is Vs-Vd. If the column voltage is set to 0 the pixel voltage decays to 0 at a fairly rapid rate determined by the load resistance and generates a potential difference between the pixel electrode and front plane. Therefore the optical state of the pixel is changed as there is a potential difference between front plane and pixel electrode. [0065] In a preferred embodiment of the driving scheme useful for display media that are sensitive to DC-imbalance, the pixel driving is reset at the end of each row driving sequence. This is done by setting all pixel electrodes to the same potential as front plane. This is done by setting the front plane to Vs-Vd, the row to be reset to Vs and all column electrodes to Vs. [0066] In another preferred embodiment of the invention, the diodes comprise organic semiconductor material, especially solution processed organic semiconductor material. It is especially preferred if the diodes and if possible also the resistors are deposited by printing techniques, especially for organic semiconductor diodes. In another preferred embodiment the display medium is a bi-stable display medium, especially a reflective display medium, and in particular an electrophoretic display medium. It is especially preferred if the back plane, the front plane and the display medium are all flexible. Geometries [0067] In another embodiment of the invention a display is manufactured by preparing a back plane structure according to the circuits described above, with the same advantageous embodiments as described for the circuit and the display, then laminating a display medium previously laminated onto an unpatterned front plane electrode structure to the back plane to make an active matrix display. [0068] The circuit components may be situated next to the pixel electrode, with lateral contacts from the appropriate terminals of the diode to the pixel, as shown in FIG. 10 for the example of the first embodiment of the invention disclosed herein. An active matrix backplane 50 comprises row lines 51 - 53 , insulators 54 disposed on top of the row lines, column lines 55 - 57 crossing the row lines at the points where the insulators are deposited, and between the row and column lines diodes 58 , resistors 59 and pixel electrodes 60 laterally oriented and connected in such as way as to form unit cells as shown in FIG. 5 . [0069] For display media that are opaque, such as electrophoretic or rotating ball displays, it may be preferable to dispose the diode matrix underneath rather than next to the pixel electrode, a geometry which may be referred to as a “vertical pixel architecture”. [0070] WO 2004/070466 discloses a version of a vertical pixel architecture, useful for e.g. electrophoretic displays, on the basis of thin film transistors (TFTs), whereby the pixel electrode is disposed above the TFT matrix, separated by a dielectric material layer, and connected to the drain electrode by means of a via hole in the dielectric. U.S. Pat. No. 6,232,950 discloses a display architecture in which conductors are disposed onto a substrate, covered by a dielectric layer with via holes, and a pixel electrode is deposited onto the dielectric layer in such a way that the via holes are filled and electrical connection is made to the lead lines. [0071] A matrix based on thin film diodes and resistors, i.e. a structure comprising not only conductive patterns but also active components comprising semiconductors may also be disposed underneath the pixel electrode. FIG. 11 demonstrates one embodiment of such a display architecture according to the invention in the example of a single pixel 100 . Upon a substrate 101 are disposed a row line 102 , resistor 103 , diodes 104 and 105 , column line 110 and a dielectric layer comprising vias 109 . Upon this is disposed a pixel electrode 106 in such a way that the vias are filled and make contact between the pixel electrode and the driving circuit. The display electrode 106 is adjacent to the display medium 107 and the front plane electrode 108 . [0072] U.S. Pat. No. 6,445,374 discloses a display architecture in which conductors are disposed onto one side of a substrate comprising via holes at appropriate locations, the pixel electrodes are disposed onto the other side of the substrate and contact is made through filling of the via holes. [0073] In another embodiment of a vertical pixel architecture for circuits according to the invention, as sketched in FIG. 12 in the example of a single pixel 200 . Upon a substrate 201 comprising vias 209 are disposed on one side of the substrate a row line 202 , resistor 203 , diodes 204 and 205 and column line 210 . On the other side of the substrate 201 is disposed a pixel electrode 206 in such a way that the vias are filled and make contact between the pixel electrode and the driving circuit. The display electrode 206 is adjacent to the display medium 207 and the front plane electrode 208 . [0074] Similar vertical pixel architectures can be based on the other embodiments of the invention disclosed herein, according to the same principles as outlined in FIGS. 11 and 12 . [0075] FIG. 13 illustrates an example of a device 130 in which the driving system of the present invention can be implemented. The device 130 is, for example, an electronic price label, an information display, etc. The device 130 comprises a controller 131 for controlling the operation of the device 130 . The device 130 also comprises a memory 132 for storing information, software programs, parameters etc. The device may also have an input element 133 for inputting information such as price data, updated versions of software, new parameter values, etc. The device 130 may also comprise a keyboard 134 which the user can use to input data to the device 130 . The display driver 136 of the device 130 forms the row and column voltages for each row address lines and column address lines so that pixels of the display 137 are in a desired state to show information to be displayed. Also when the information to be displayed changes the display driver 136 makes the necessary adjustments to the row and column voltages. It is noted here that the row and column voltages are dependent on inter alia which of the embodiments disclosed herein is used. [0076] Information to be shown may be stored into the memory 132 . For bi-stable media, especially those which are sensitive to DC-imbalance and/or such media in displays that should display grey scales, the memory may contain also a look-up table in which the current state of each pixel is stored, since the driving waveform needed to switch the pixel to another state or maintain the current state depends on the current state of the pixel. The controller 130 reads the information from the memory 132 e.g. pixel by pixel and sends the information to the display driver 136 . The display driver 136 sets correct row and column voltages on the row and column address lines as was disclosed above in connection with FIG. 9 . Changes to row and column voltages are only necessary when one or more pixel states need to be changed thus power consumption can be kept very low. [0077] The driving circuit of the invention is also applicable to colour display. For colour displays each pixel element is divided into a plurality of sub-pixels, e.g. red, green and blue or cyan, yellow and magenta, each created for example by use of an appropriate colour filter with a black and white display medium or use of patterned display media with different colours. In some cases a white sub-pixel may also be added to a reflective display to increase the display brightness. Each sub-pixel will then be controlled by its own pixel control circuit as disclosed herein.

An active-matrix electronic display including a switching circuit for each pixel to control the optical state of the display. The switching circuit includes at least one diode and at least one load impedance for each circuit. The front plane electrode of the display may be unpatterned over a significant portion of the display. The display architecture is especially useful for bi-stable display media that require active matrix addressing, for example electrophoretic displays, and for applications using diodes based on organic semiconductors and/or printed diodes.

The present invention relates to a unidirectional glass fabric produced with continuous yarn which is twisted, plied or has zero twisting turns, with different gram weights and interlaced with thin glass yarns as a stabilizing binding, as well as to use thereof in the manufacture of printed circuits. BACKGROUND OF THE INVENTION Glass fabric is used nowadays with success in a wide range of applications. Among the main ones, mention may be made of those applications involving advanced structural composites for the aeronautical and naval industries and dielectric composites for the electrical and electronics industry. In particular, the Applicant's interest is directed towards the manufacture of glass fabrics for use in the electrical and electronics industry, preferably the construction of laminates for printed circuits and the manufacture of fabrics and gauzes used as a reinforcement in numerous industrial applications. The miniaturization of electronic devices is giving rise to various assembly problems, including the concentration of tracks on printed circuits and hence the need for making the tracks thinner. This innovative process has not radically affected the criteria for laminate production, but is requiring the use of glass fabrics which are much more refined than those currently used. In particular, the weaving industry is having to find solutions for the problems associated with the surface of the fabrics, which need to be increasingly flat and smooth and as far as possible devoid of loose pile and textile defects in general, and with dimensional stability, which must be kept as low as possible. It is obvious that conventional glass fabric, which constitutes the structural support of the laminate, based on a cloth weave, is no longer suited for tolerating a reduction in these parameters. Consequently it is necessary to provide a glass fabric with an increasingly higher performance compared to the fabrics currently used. On account of the increasingly stringent specifications for printed circuits, the person skilled in the art is now having to regard as critical certain aspects of the laminates, such as the surface waviness, dimensional stability, warping, perforability, thickness, dielectric constant, and others, such that it can be said that the characteristics of the laminate depend not only on the resins used, but also on the structure of the glass fabric. Pure unidirectional glass products used for advanced composites are known. A product of this kind consists of a series of undirectional yarns arranged next to one another. A unidirectional product of this type cannot be used for the manufacture of monolithic glass-reinforced resin laminates employing conventional technology on account of the difficulty in handling the layer of undirectional yarns and in particular the need for a substantial modification in the technique for molding the glass-reinforced resin sheets currently used. In fact, a layer of undirectional yarns held together by epoxy resin would be unable to withstand the standard molding pressures and the yarns, which will move during molding, would cause voids or irregular distribution between glass and resin. One solution to the problem is illustrated in the Applications EP 0478051 and WO 9402306, both in the name of Akzo, which provide a method for the manufacture of boards for printed circuits reinforced with a unidirectional glass product. These methods involve the use of extremely complex and costly machines. There is currently the need, therefore, for a glass fabric which is unidirectional as far as possible and can be processed with the technology available, but which is not affected by the aforementioned problems, in particular structural stability, and which is able to produce monolithic laminates which satisfy the requirements for printed circuits. SUMMARY OF THE INVENTION It has now been discovered that a unidirectional fabric produced with a continuous glass yarn which is twisted, has a low number of twists or zero twisting turns, with different gram weights and interlaced with thin glass yarns as a binding permits the manufacture of laminates for printed circuits satisfying the requirements imposed by progressive miniaturisation. Therefore, the present invention relates to a unidirectional fabric produced with continuous glass yarn which is twisted, has a low number of twists or zero twisting turns with different gram weights, characterized in that it is interlaced warpwise with glass yarns of 5.5 to 34 Tex at a spacing of up to 20 cm from each other and with a leno interwoven binding. The present invention also relates to the use of said glass fabric for the manufacture of laminates for printed circuits, as well as the printed circuits comprising said laminates. The present invention provides a fabric as a result of which it is possible to obtain monolithic glass-reinforced resin laminates possessing excellent properties for use in the manufacture of printed circuits using conventional techniques and equipment. This result is obtained owing to the stability of the unidirectional fabric according to the present invention. BRIEF DESCRIPTION OF THE DRAWINGS The subject of the present invention, in its various embodiments, and the advantages arising therefrom will be described in the detailed description which follows and with the aid of the drawings in which: FIG. 1 shows in schematic form an axonometric view of a conventional fabric; FIG. 2 shows a profile view of the fabric according to FIG. 1, along the section II--II; FIG. 3 shows in schematic form an axonometric view of the fabric according to the present invention; FIG. 4 shows a profile view of the fabric according to FIG. 3 along the section IV--IV; FIG. 5 shows a profile view of the fabric according to FIG. 3 along the section V--V. DETAILED DESCRIPTION OF THE INVENTION In the Figures, the reference (1) denotes the warp yarns, (2) the weft yarns and (3) the binding yarns. In the fabric according to the present invention, the interlacing warpwise binding yarn is obtained using glass yarns of 5.5 to 22 Tex. The two binding yarns lie, in pairs, next to the bottom of binding yarns and are not visible on the fabric. In the fabric these yarns (3) are interlaced with the yarns (2), being alternately located on the first weft on the upper right-hand side and on the second weft on the bottom left-hand side, resulting in a binding well known to textile experts by the name of "leno interwoven binding". With insertion of the binding yarns (3) which are referred to as "interlacing", stabilization of the bottom yarns is obtained, which allows handling of the unidirectional fabric without slipping of the yarns which could rise to overtensioning and very severe distortion during the subsequent resin impregnation phase. The yarns with this invention thus remain perfectly aligned with one another and uniformly tensioned, thus avoiding becoming displaced, superimposed or bunched together under the molding pressures occurring in the standard technological process used nowadays and resulting in a uniform resin/glass ratio in the mass of the laminate. In a first embodiment of the present invention, the unidirectional fabric is composed of yarn arranged warpwise of at least 90% of the total weight of the fabric. In the unidirectional fabric according to the present invention, the weft yarns (2) are considered solely to be bindings of the warp yarns (1). The interlacings may be arranged at a maximum spacing from one another of 20 cm. In a preferred embodiment a spacing of between 10 and 15 cm and a number of wefts of up to 8 per cm is envisaged. The yarn which forms the fabric is formed by conventional filaments, preferably with a diameter of between 5 and 13 microns. In a preferred embodiment, the yarn has a Tex value of between 22 and 136. A particularly preferred embodiment envisages a unidirectional fabric with a warp having a value of between 22 and 136, preferably 74 Tex, the weft with a value of between 11 and 68, preferably 34 Tex, and the interlacings with a value of between 5 and 34, preferably 11 Tex. The fabric according to the present invention may be processed perfectly using standard impregnation and molding processes with obvious economic advantages and without the need for investment in new technology. The laminates made of glass-reinforced resin, for example glass-reinforced epoxy resin, comprising the fabric according to the present invention as the support structure, have very low surface roughness values (Wt), less than 2 μm. By comparison, the roughness values of conventional laminates are 4 μm. With low roughness of the laminate, further reductions in the dimensions of the printed thin copper tracks become possible, with considerable advantages in terms of the overall performance of the panels, as well as direct application of the thin copper tracks, with major economic and ecological advantages. Using this system, it is possible to achieve savings in copper and eliminate the etching operation performed with toxic acids. With the present invention it is also possible to obtain dimensional stability values which are at least 60% lower than the current standard values equivalent to 200 ppm. This is possible owing to the intrinsic linearity of the unidirectional fabric which does not allow, as instead occurs in fabrics with a standard weave, elongations during molding of the laminate and consequent contractions during the ensuing processing stages. With low dimensional stability values, application of the dry film and in general manufacture of the multi-layers may be controlled more easily and therefore achieved in a more efficient and economical manner. Other advantages obtained with the laminates described above are the uniform perforability of the laminate with an improved perforation quality; greater economy of the perforating operation with savings in terms of the wear of the drilling tips; surface devoid of inclusions and excessive thicknesses which cause thinning of the copper; uniform thickness and composition of the laminate which helps achieve a more uniform "dielectric constant" over the entire printed circuit, in particular for applications involving high frequencies such as those of 3-30 GHz used in telecommunications and satellite applications; greater dimensional stability D stab -CTE α x ,y ; smaller number of microscopic voids; longer "measling" resistance times; greater economy during production of the fabric. The use of the novel unidirectional fabric also gives rise to advantages in connection with the laminate manufacturing process. Since the novel fabric has a wetting time which is 50% less compared to that of a standard fabric, the epoxy resin used during impregnation may be prepared with mixtures which are more viscous and hence contain a smaller quantity of solvent which is to be evaporated; consequently it is possible to achieve a higher working speed with a saving in the amount of solvent used. Moreover, the unidirectional fabric thus produced is particularly suitable for impregnation with hot-melt formulated resin systems and solvent-free resins, resulting in further savings in solvent, equivalent to nearly 100%, and even faster impregnation speeds. The present invention also provides a solution to the problem of imperfect cleanliness owing to the presence of the residues of organic compounds, such as starch, used in the weaving process and then removed. The presence of these residues in the laminate alters the chemical and physical properties of the latter. It is obvious that the standard fabrics are very compact and hence very difficult to clean owing to the difficulty which the heat has in penetrating them and hence the difficulty which the distillation vapors of the combusted size have in escaping. On the other hand, the fabric according to the present invention, owing to its greater permeability, allows optimum cleaning without the structure of the fabric being altered during the course of the operation.

A unidirectional fabric produced with a continuous glass yarn which is twisted, plied or has zero twisting turns, with different gram weights. Interlacings of thin glass binding yarns for stabilizing the fabric extend warpwise to engage weft yarns in a leno interweaving. The fabric is used in the manufacture of printed circuits and in industrial applications.

CROSS-REFERENCE TO RELATED APPLICATION This is a continuation application of application Ser. No. 09/629,362 filed Aug. 1, 2000, now U.S. Pat. No. 6,757,286 which was a continuation application of application Ser. No. 09/475,623 filed Dec. 30, 1999, now abandoned which was a continuation application of application Ser. No. 08/823,078 filed Mar. 24, 1997 which issued as U.S. Pat. No. 6,041,057. FIELD OF THE INVENTION The present invention relates to data communication networks. More particularly, the present invention relates to methods for configuring, maintaining connectivity in and utilizing an ATM network. BACKGROUND OF THE INVENTION A local area network (LAN) segment is a computer sub-network which includes multiple stations in the same physical area communicating by forwarding messages on a shared LAN media. Stations on different LAN segments in the same physical area often communicate through a shared LAN switching fabric, which selectively forwards messages received over the fabric to the destination LAN segment. Stations on different LAN segments in different physical areas, in contrast, often communicate over a backbone network which interconnects multiple LAN switches on the edge of the network. In such an arrangement, each LAN switch selectively forwards messages received over the backbone network to the destination LAN segment. Communication on LAN segments, and communication between LAN segments over LAN switches, is broadcast-oriented. A station desiring to communicate with another station on the same LAN segment does not need to know where the destination station is located on the segment. Instead, the source station relies on the broadcast capability of the LAN media to propagate all messages to all stations on the segment. An interface on the intended destination station captures the message. Other interfaces on the segment ignore the message. Similarly, if a message propagated on a LAN segment is destined for a station on a different LAN segment associated with the same LAN switch, the LAN switch interconnecting the two segments will typically capture and propagate the message on a switching fabric connecting the two segments. In turn, an interface on the LAN switch associated with the intended destination LAN segment captures and propagates the message on the segment. Other interfaces on the LAN switch ignore the message. Again, there is no requirement that the source station know where the intended destination station resides within the network for successful communication. Rather, communication between the stations on different LAN segments over the LAN switch is “seamless” because the stations can communicate as if they are on the same LAN segment. In contrast, communication over backbone networks is not always broadcast-oriented. One widely-used backbone technology is asynchronous transfer mode (ATM). Communicating over an ATM network requires that point-to-point or point-to-multipoint virtual connections be established between switches on the edge of the network. Thus, it is necessary for complete connectivity in ATM backbone networks to configure every source switch with virtual connections to every destination switch. Such configuration has generally required either manual configuration by a network administrator or implementation of ATM signaling procedures. Additional configuration has been required to maintain connectivity in the event an established link fails. As a result of these configuration and maintenance requirements, performance of ATM backbone networks has been hindered. ATM's configuration demands have become even greater with the advent of virtual local area networks (VLANs). A VLAN is an aggregate of LAN segments which are part of the same logical group, but not necessarily the same physical group. By limiting the flow of messages across VLAN boundaries in an ATM network, VLANs can conserve network bandwidth and enhance network security. However, VLANs can at the same time lessen network robustness by requiring configuration of additional overlay virtual connections. Robustness problems in ATM networks have been further exacerbated by using configuration services which by necessity or design give microprocessors, rather than custom logic, a primary role in message forwarding. Accordingly, there is a need for more efficient services for configuring and maintaining connectivity in ATM networks. SUMMARY OF THE INVENTION It is an object of the present invention to provide an improved ATM network in which virtual connections are self-configuring. It is another object of the present invention to provide an improved ATM network in which multiple requests for virtual connections can be made in a single message. It is another object of the present invention to provide an improved ATM network in which a first set of virtual connections are self-configuring along a best path. It is another object of the present invention to provide improved ATM network in which a second set of virtual connections are self-configuring along a next-best path. It is another object of the present invention to provide an improved ATM network which can support multiple VLANs. It is another object of the present invention to provide an improved ATM network in which message forwarding is carried out primarily in custom logic. These and other objects of the present invention are achieved by methods for configuring and utilizing tagged virtual connections between source and destination switches on the edge of an ATM network. In one aspect of the invention, neighboring switches share topology information. Topology information includes switch identifying information and path cost information. Switch identifying information includes switch identifiers and VLAN information for particular switches. Path cost information includes information about the relative cost of using particular paths to reach particular switches. Topology information is shared by neighboring switches via topology messages. As a result of topology learning, switches learn about other switches and the most efficient paths for forwarding end-user messages to particular switches. In another aspect of the invention, neighboring switches enable links for tag switching. Link enablement is requested by forwarding hello requests. Hello requests include a range of tag values proposed for use on a particular link. Link enablement is established by forwarding hello responses. Hello responses include a positive or negative acknowledgment of a hello request. As a result of link enablement, switches learn the available links for use when requesting tagged virtual connections for forwarding end-user messages. In another aspect of the invention, edge switches and combination switches, as source switches, initiate requests for point-to-point tagged virtual connections to one another, as destination switches. Requests for point-to-point tagged virtual connections are initiated by forwarding a tag allocation request to a neighboring switch along the best path to a destination switch. Tag allocation requests include allocation information, including a source switch identifier, a destination switch identifier and a tag value. Source switches initiate a request for each destination switch for each shared VLAN. Multiple requests may be included in a single tag allocation message to conserve network bandwidth. Transit and combination switches, as neighboring switches, respond to each tag allocation request received by relaying a related tag allocation request to another neighboring switch, if any, along the best path to the destination switch. The relay process is repeated until a tag allocation request arrives at the destination switch. Switches select a different outbound tag value for each requested point-to-point virtual connection so that when an end-user message encoded with a particular tag value is subsequently presented for forwarding, the switch will be able to associate the message with a distinct virtual connection between a particular source and destination switch. As a result of point-to-point tag allocation, a full mesh of point-to-point virtual connections is established for forwarding known unicast end-user messages from source switches to destination switches using a simple look-up operation which resolves identifiers encoded in such messages to outbound ATM ports and outbound tags. In another aspect of the invention, edge switches and combination switches, as source switches, initiate requests for point-to-multipoint tagged virtual connections to one another, as destination switches. Requests for point-to-multipoint tagged virtual connections are initiated by forwarding a set of tag allocation requests to a set of neighboring switches along the spanning tree path to the set of destination switches sharing a VLAN with a source switch. Tag allocation requests include allocation information, including a source switch identifier, an identifier of the shared VLAN and a tag value. Source switches initiate a request for each shared VLAN. Each point-to-point multipoint tag allocation request is relayed by transit and combination switches, as neighboring switches, until a set of tag allocation requests arrives at the set of destination switches. As a result of point-to-multipoint tag allocation, a full mesh of point-to-multipoint virtual connections is established for forwarding broadcast, multicast and unknown unicast end-user messages from source switches to destination switches sharing a particular VLAN by performing a simple look-up operation using custom logic which resolves identifiers encoded in such messages to outbound ATM ports and outbound tags. In another aspect of the invention, end-user messages are forwarded from source switches to destination switches on the established point-to-point tagged virtual connections. On source switches, a destination switch identifier associated with an end-user message is resolved to a forwarding ATM port identifier and a first tag value. The message is forwarded over the forwarding ATM port to a neighboring switch. The neighboring switch resolves the first tag value to a forwarding ATM port identifier and second tag value and forwards the message over the forwarding ATM port to a second neighboring switch, if any. The resolution and forwarding process is repeated by additional neighboring switches, if any, until the end-user message arrives at the destination switch. The resolution and forwarding process may be advantageously implemented in custom logic using a table look-up operation. In another aspect of the invention, end-user messages are forwarded from source switches to destination switches on the established point-to-multipoint tagged virtual connections. On source switches, the VLAN identifier associated with an end-user message is resolved to a set of forwarding ATM port identifiers and a first set of tag values. The message is forwarded over the set of forwarding ATM ports to a set of neighboring switches. The neighboring switches resolve the first set of tag values to a set of forwarding ATM port identifiers and second set of tag values and forward the message over the set of forwarding ATM ports to a second set of neighboring switches, if any. The resolution and forwarding process is repeated by additional neighboring switches, if any, until the end-user message arrives at the set of destination switches belonging to the shared VLAN. The resolution and forwarding process may be advantageously implemented in custom logic using a table look-up operation. In another aspect of the invention, switches, in addition to initiating and relaying requests for point-to-point virtual connections to destination switches on the best paths, initiate and relay requests for point-to-point virtual connections on the next-best paths. As a result of next-best path tag allocation, if any best path link between a source and destination switch pair becomes disabled, an end-user message can be advantageously diverted to a next-best path to the destination switch. The present invention can be better understood by reference to the following detailed description, taken in conjunction with the accompanying drawings which are briefly described below. Of course, the actual scope of the invention is defined by the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic of a communication network operating in accordance with the present invention; FIG. 2 is a functional diagram of an edge switch operating in accordance with the present invention; FIG. 3 is a functional diagram of a transit switch operating in accordance with the present invention; FIG. 4 shows the general format of a topology message generated by a switch operating in accordance with the present invention; FIG. 5 shows the general format of a hello request message generated by a switch operating in accordance with the present invention; FIG. 6 shows the general format of a hello response message generated by a switch operating in accordance with the present invention; FIG. 7 shows the general format of a tag allocation message generated by a switch operating in accordance with the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1 , a computer network 1 operating in accordance with a preferred embodiment of the present invention is shown. In the illustrated embodiment, network 1 includes stations S.sub. 1 , S.sub. 4 , S.sub. 5 interconnected to one another over ATM cloud 60 . ATM cloud is a connection-oriented medium characterized by switches and ATM links for forwarding information in fixed-length cells in accordance with governing ATM standards. Along the paths interconnecting stations S.sub. 1 , S.sub. 4 , S.sub. 5 are switches 10 , 20 , 30 , 40 , 50 . In the illustrated embodiment, network 1 includes edge switches 10 , 40 , transit switches 20 , 30 and combination switch 50 . It will be appreciated, however, that a network operating in accordance with the present invention may include two or more edge or combination switches and any number of transit switches interconnected by two or more sets of links. Edge switches are characterized by having one or more ports associated with LAN media, such as Ethernet, Token Ring or FDDI and one or more ports associated with an ATM cloud. In the illustrated embodiment, edge switch 10 has a LAN port associated with LAN segment 14 and station S.sub. 1 . Edge switch 40 has a LAN port associated with LAN segment 44 and station S.sub. 4 . Edge switches 10 , 40 also each have a single ATM port to ATM cloud 60 . Each edge switch port is associated with one or more VLANs. Transit switches are characterized by having two or more ATM ports associated with an ATM cloud. In the illustrated embodiment, transit switches 20 , 30 each have two ports to ATM cloud 60 . Combination switches are characterized by having one or more LAN ports associated with LAN media and two or more ATM ports associated with an ATM cloud. In the illustrated embodiment, combination switch 50 is associated with LAN segment 54 and station S.sub. 5 . Combination switch 50 also has two ATM ports to ATM cloud 60 . Each combination switch port is associated with one or more VLANs. Switches 10 , 20 , 30 , 40 , 50 are each assigned a unique switch identifier and are immediately interconnected to neighboring switches by links 12 , 23 , 24 , 25 , 35 . Links are preferably fiber optic or twisted pair cables supporting various bandwidths. FIGS. 2 and 3 present functional diagrams of switches operative in accordance with a preferred embodiment of the present invention. The illustrated functionality may be implemented using any suitable logic, although a custom logic implementation is preferred where indicated below. Referring to FIG. 2 , a functional diagram of an edge switch 200 operating in accordance with a preferred embodiment of the present invention is shown. Switch 200 includes TOP ADV means 210 . Means 210 serves to advertise network topology information to neighboring switches. Means 210 generates topology messages encoded with associated pairs of switch identifiers, path cost values and VLAN identifiers for switches in the network. Means 210 also periodically forwards topology messages to neighboring switches over active ATM ports of switch 200 . Path cost values encoded in topology messages reflect the aggregate cost of the links which must be traversed on a particular path over switch 200 to reach a particular switch. Path costs are added upon receipt of topology messages from neighboring switches. Thus, when switch 200 advertises its own path cost information to a neighboring switch, switch 200 assigns a path cost value of “0”. When the neighboring switch advertises the information learned about switch 200 , the neighboring switch assigns a path cost for switch 200 based on the bandwidth of the link on which the advertised information was received from switch 200 . Topology messages are forwarded periodically on active ATM ports of switch 200 . Switch 200 also includes TOP LRN means 220 . Means 220 serves to learn the topology of the network from topology information advertised by other switches. Means 220 assigns a path cost to each link on which topology messages are received, based on the bandwidth of the link. Means 220 further calculates aggregate path cost values by adding the path cost assigned to a link to the path cost value encoded in a topology message received on the link. Means 220 further associates the switch identifier and VLAN identifier in a received topology message with the aggregate path cost value and the identifier of the receiving ATM port and stores the information as an associated pair in a topology database. The topology database may be accessed using known memory access mechanisms. Switch 200 also includes LINK ENAB means 230 . Means 230 serves to determine if a neighboring switch is able to establish tagged virtual connections on a particular link. Means 230 determines from topology information whether a switch is a neighboring switch. Means 230 also associates a neighboring switch with a particular link. Means 230 further establishes a virtual connection to the neighboring switch on the link. Means 230 also forwards on the virtual connection a hello request message encoded with a range of tag values that switch 200 proposes to use when tag switching with the neighboring switch on the link. Means 320 further determines from information encoded in a hello response message received on the link whether the neighboring switch accepts or rejects the request to enable the link for tag switching with switch 200 . Switch 200 initiates a hello request message whenever switch 200 learns of a neighboring switch. Switch 200 also includes EDGE TAG SET means 240 . Means 240 serves to initiate requests for tagged point-to-point virtual connections for forwarding known unicast end-user messages. It will be appreciated that a known unicast message is a message encoded with information which switch 200 can resolve to a point-to-point tagged virtual connection to a particular destination switch. Means 240 determines from topology information whether a destination switch shares a VLAN with switch 200 . Means 240 also determines from topology information the forwarding ATM port on switch 200 associated with the best path to the destination switch. Means 240 further selects a tag value within the range of values available on the forwarding link. Means 240 further generates a tag allocation message encoded with a tag allocation request. The tag allocation request includes the selected tag value, the identifier of switch 200 and the identifier of the destination switch. Means 240 further forwards the tag allocation message to a neighboring switch on the forwarding link. Means 240 also serves to initiate requests for point-to-multipoint tagged virtual connections for forwarding broadcast, multicast and unknown unicast end-user messages. It will be appreciated that such messages are messages not encoded with information which switch 200 can resolve to a point-to-point tagged virtual connection to a particular destination switch. A point-to-multipoint tagged virtual connection is requested for each VLAN shared by switch 200 . Means 240 determines a set of forwarding ATM ports on switch 200 associated with the spanning tree path to a set of destination switches for a particular VLAN. Means 240 further selects a set of tag values within the range of values available on the set of forwarding links. Means 240 further generates a set of tag allocation messages encoded with a set of tag allocation requests for the set of destination switches. Each tag allocation request includes a selected tag value, the identifier of switch 200 and the identifier of the shared VLAN. Means 240 further forwards the set of tag allocation messages to a set of neighboring switches over the set of forwarding links. The Spanning Tree Protocol (STP) running in accordance with governing IEEE standards is preferably used to determine the spanning tree path. Means 240 also implements the foregoing procedures to initiate requests for point-to-point tagged virtual connections on the next-best path to destination switches. Means 240 further encodes multiple tag allocation requests in a single tag allocation message. Switch 200 initiates a point-to-point and a point-to-multipoint tag allocation request whenever switch 200 learns of a new VLAN shared by switch 200 and a destination switch. Edge switch 200 also includes EDGE TAG LRN means 250 . Means 250 serves to learn the tag values allocated by switch 200 for the requested tagged virtual connections. Means 250 associates a destination switch identifier with the forwarding ATM port identifier and the tag value encoded in an outbound tag allocation request for a point-to-point virtual circuit and stores the associated pair in a memory means. Means 250 also associates a set of tag values encoded in a set of outbound tag allocation requests for a point-to-multipoint virtual circuit with a set of forwarding ATM port identifiers and stores the associated pairs in a memory means. Means 250 also serves to learn the tag values allocated by neighboring switches for the tagged virtual connections for which switch 200 is a destination switch. Means 250 associates a tag value and a source switch identifier in a received point-to-point tag allocation request and stores the associated pair in a receiving database. Means 250 also associates a tag value and a source switch identifier in a received point-to-multipoint tag allocation request and stores the associated pair in a receiving database. Receiving databases may be accessed using known memory access mechanisms. Receiving databases advantageously enable switch 200 to perform a source learning operation on incoming end-user messages by providing switch 200 with information sufficient to resolve source station addresses encoded in such messages to particular source switch identifiers. Means 250 also, upon performing such a source learning operating, associates the learned source station address with a forwarding ATM port identifier and tag value previously stored in association with a particular destination switch identifier. Means 250 further stores the associated station address, forwarding ATM port identifier and tag value as a related pair in a forwarding database. Forwarding database on switch 200 may be accessed using known memory access mechanisms. Edge switch 200 also includes EDGE MSSG FWD means 260 . Means 260 serves to assign tag values to known unicast end-user messages and forward such messages along the established point-to-point tagged virtual connections. Means 260 resolves information encoded in a known unicast end-user message to a forwarding ATM port identifier and a first tag value retrieved from a forwarding database. Means 260 also encodes the message with the first tag value and forwards the message to a neighboring switch on the forwarding link. A look-up operation using custom logic is contemplated for retrieving information from the forwarding database. Custom logic may be implemented in an application-specific integrated circuit (ASIC). Means 260 also serves to assign tag values to broadcast, multicast, and unknown unicast end-user messages and forward such messages along the established point-to-multipoint tagged virtual connections. Means 260 resolves information encoded in a broadcast, multicast or unknown unicast end-user message to a set of forwarding ATM port identifiers and a set of first tag values retrieved from a memory means. Means also copies the end-user message. Means 260 also encodes the end-user message with the set of tag values and forwards the message to a set of neighboring switches on the set of forwarding links. Referring to FIG. 3 , a functional diagram of a transit switch 300 operating in accordance with a preferred embodiment of the present invention is shown. As with edge switch 200 , transit switch 300 has TOP ADV means 210 , TOP LRN means 220 and LINK ENAB means 230 . Switch 300 also includes TRANS TAG SET means 310 . Means 310 serves to relay requests for point-to-point tagged virtual connections initiated by source switches. Means 310 determines from topology information the forwarding ATM port on switch 300 associated with the best path to a destination switch. Means 310 further selects a tag value within the range of tag values available on the forwarding link. Means 310 further generates a tag allocation message encoded with a tag allocation request. Means 310 further forwards the tag allocation message to a neighboring switch on the forwarding link. Means 310 further implements the foregoing procedures to relay a request initiated by a source switch for a virtual connection on the next-best path to a destination switch. Means 310 further encodes multiple tag allocation requests in a single tag allocation message. Means 310 also serves to relay requests for point-to-multipoint tagged virtual connections initiated by a source switch. Means 310 determines the set of forwarding ATM ports on switch 300 associated with the spanning tree path to a set of destination switches. Means 310 further selects a set of tag values within the range of values available on a set of forwarding links. Means 310 further generates a set of tag allocation messages encoded with a set of tag allocation requests. Means 310 further forwards the set of tag allocation messages to a set of neighboring switches over the set of forwarding links. Switch 300 also includes TRANS TAG LRN means 320 . Means 320 serves to learn the tag values selected by upstream neighboring switches for the requested tagged point-to-point virtual connections. Means 320 associates a tag value encoded in an inbound tag allocation request with the an identifier of a forwarding ATM port and a tag value selected for encoding in an outbound tag allocation request and stores the associated pair in a forwarding database. Means 320 also serves to learn tag values selected by upstream neighboring switches for requested point-to-multipoint virtual connections. Means 320 associates a tag value encoded in an inbound tag allocation request with an identifier of a set of forwarding ATM ports and a set of tag values selected for encoding in an outbound tag allocation request and stores the associated pair in a forwarding database. Forwarding database on switch 300 may be accessed using known memory access mechanisms. Switch 300 also includes TRANS MSSG FWD means 330 . Means 330 serves to assign tag values to known unicast end-user messages and forward such messages along the established point-to-point virtual connections. Means 330 resolves a tag value encoded in an inbound end-user message to a forwarding ATM port identifier and an outbound tag value retrieved from a forwarding database. Means 330 also encodes an end-user message with the outbound tag value and forwards the message over the forwarding ATM port to a neighboring switch. Means 330 also serves to tag and forward messages along the established point-to-multipoint virtual connections. Means 330 resolves a tag value encoded in an inbound end-user message to a set of outbound ATM port identifiers and a set of outbound tag values retrieved from a forwarding database. Means 330 also encodes a set of end-user messages with the set of outbound tag values and forwards the set of end-user messages to a set of neighboring switches over the set of forwarding links. A look-up operation using custom logic is contemplated for retrieving information from the forwarding database. Custom logic may be implemented in an application-specific integrated circuit (ASIC). Combination switches combine the functionality of edge switch 200 and transit switch 300 in a single switch. Thus, combination switches include TOP ADV means 210 , TOP LRN means 220 , LINK ENAB means 230 , EDGE TAG SET means 240 , EDGE TAG LRN means 250 , EDGE MSSG FWD means 260 , TRANS TAG SET means 310 , TRANS TAG SET means 320 and TRANS MSSG FWD means 330 . Referring to FIG. 4 , the general format of a topology message 400 generated in accordance with a preferred embodiment of the present invention is shown. Message 400 includes a type field 410 encoded with a value identifying message 400 as a topology message. Message 400 includes version field 420 encoded with a value indicating the protocol version number of message 400 . Different protocol numbers may be used as enhancements are made to the protocol. Message 400 also includes flags field 430 indicating whether message 400 is a flash update message. Flash update messages contain topology information not included in previous topology messages. Message 400 further includes number of blocks (NOB) field 440 . NOB field 440 identifies the number of topology information blocks included in message 400 . Message 400 also includes “my switch” field 450 encoded with the identifier of the switch which generated the message 400 . Topology information blocks include topology information for a particular switch. One information block is included for each switch known to the switch which generated message 400 . Message 400 has first information block 460 . Block 460 includes subject switch field 470 encoded with the identifier of the particular switch which is the subject of the information in block 460 . Block 460 also has path cost field 472 . Path cost field 472 contains a value indicating the cost to reach the subject switch over the path that message 400 was received on. Path costs are assigned to each link based on the bandwidth of the link, with larger values assigned to slower links. In a preferred embodiment, a value of “1” indicates a 100 gigabit per second link, a value of “10” indicates a 10 gigabit per second link, a value of “100” indicates a 1 gigabit per second link, a value of “1000” indicates a 100 megabit per second link, a value of “10000” indicates a 10 megabit per second link, and so on, although it will be appreciated that it is the relationship between the values rather than the actual values which is significant. Block 460 also includes number of VLANs (NOV) field 474 . NOV field 474 contains a value indicating the number of VLANs active on the subject switch (and also the number of VLAN fields 476 , 478 to follow NOV field 474 ). VLAN fields 476 , 478 each contain an identifier of a VLAN active on the subject switch. It will be appreciated that message 400 may contain additional information blocks for additional switches having the same general format as block 460 . Referring to FIG. 5 , the general format of a hello request message 500 generated in accordance with a preferred embodiment of the present invention is shown. Message 500 includes a type field 510 encoded with a value identifying message 500 as a hello request message. Message 500 includes version field 520 encoded with a value indicating the protocol revision number of message 500 . Message 500 includes minimum tag value field 530 encoded with the lowest tag value available for use in tag switching on the link on which message 500 is forwarded. Message 500 also includes maximum tag value field 540 encoded with the largest tag value available for use in tag switching on the link on which message 500 is forwarded. Referring to FIG. 6 , the general format of a hello response message 600 generated in accordance with a preferred embodiment of the present invention is shown. Message 600 includes a type field 610 encoded with a value identifying message 600 as a hello response message. Message 600 includes version field 620 encoded with a value indicating the protocol revision number of message 600 . Message 600 also includes acknowledgment field 630 encoded with a value indicating whether the switch generated message 600 will enable the link on which message 600 is forwarded for tag switching with the neighboring switch which generated the hello request message to which message 600 is responsive. Referring to FIG. 7 , the general format of a tag allocation message 700 generated in accordance with a preferred embodiment of the present invention is shown. Message 700 includes type field 710 encoded with a value identifying message 700 as a tag allocation message. Message 700 includes version field 720 encoded with a value indicating the protocol revision number of message 700 . Message 700 also has a number of requests (NOR) field 730 encoded with a value indicating the number of tag allocation requests contained in message 700 . Message 700 also includes one or more allocation request blocks. First request block 740 contains a type field 742 encoded with a value indicating the requested virtual connection type. Point-to-point and point-to-multipoint are the contemplated types. Request block 740 also includes a source switch field 744 . Source switch field 744 is encoded with the identifier of the switch making the tag allocation request contained in the request block 740 . Request block 740 also includes destination switch field 746 . For requested point-to-point virtual connections, destination switch field 746 is encoded with the identifier of the destination switch. For requested point-to-multipoint virtual connections, field 746 is encoded with the identifier of the shared VLAN. Request block 740 further includes tag field 748 . Tag field 748 is encoded with the tag value selected by the switch which generated message 700 for forwarding end-user messages on the requested virtual connection. Message 700 may contain additional request blocks for additional requests having the same general format as block 740 . In a preferred embodiment of the present invention, tag-switched communication over ATM network is accomplished in four steps: topology learning, link enablement, tag allocation and message forwarding. Returning to FIG. 1 , in a preferred topology learning step, switches 10 , 20 , 30 , 40 , 50 periodically forward topology messages to neighboring switches on links 12 , 23 , 24 , 25 , 35 . Topology messages include switch information blocks including switch identifiers, path cost values and VLAN information for particular switches. Neighboring switches associate the information with the receiving link and store the associated pairs in their topology databases. As a result of topology learning, switches 10 , 20 , 30 , 40 , 50 learn the identity and VLAN membership and the most efficient paths for forwarding end-user messages to particular switches. The path associated with the lowest path cost to a particular switch over an enabled link is considered the best path to the particular switch. The path associated with the second lowest path cost to a particular switch over an enabled link is considered the next-best path to the particular switch. In a preferred link enablement step, switches 10 , 20 , 30 , 40 , 50 determine if neighboring switches are able to establish tagged virtual connections on the learned paths. Switches 10 , 20 , 30 , 40 , 50 forward hello request messages to neighboring switches on links 12 , 23 , 24 , 25 , 35 . In response to hello request messages, neighboring switches forward hello response messages accepting or rejecting the requests to enable links 12 , 23 , 24 , 25 , 35 for tag switching. In a preferred tag allocation step for point-to-point tagged virtual connections, edge switches 10 , 40 and combination switch 50 , as source switches, initiate requests for point-to-point virtual connections for forwarding known unicast messages to one another, as destination switches. A point-to-point tagged virtual connection is requested for each source and destination switch pair for each shared VLAN. Each tag allocation request includes the source switch identifier, the destination switch identifier and a first tag value. Each tag allocation request is forwarded to a neighboring transit or combination switch on the best path to the destination switch. The neighboring switch responds by generating a tag allocation request encoded with the source switch identifier, the destination switch identifier, and a second tag value and forwarding the request to a second neighboring switch, if any, on the best path to the destination switch. Similar messages are generated and forwarded by each additional neighboring switch, if any, on the best path, until a tag allocation request is received by the destination switch. Switches along the path of the requested point-to-point virtual connections store the tag allocation information in a memory means. On the source switch, the destination switch identifier, the forwarding ATM port identifier and the first tag value are associated and stored as an associated pair in a memory means. On each neighboring switch, the inbound tag value is associated with a forwarding ATM port identifier and the outbound tag value and stored as an associated pair in a forwarding database. On the destination switch, the source switch identifier, the receiving ATM port identifier and the inbound tag value are stored as an associated pair in a receiving database. In a more preferred tag allocation step, switches also initiate and relay requests for next-best path virtual connections to destination switches. Switches may be configured to initiate requests for next-best path virtual connections only if they are on the best path to a destination switch from the perspective of the source switch. Alternatively, switches may be configured to initiate requests for next-best path virtual connections if they are on the best or next-best path to the destination switch from the perspective of the neighboring switch from which a tag allocation request is received. Requests for next-best path virtual connections may be initiated concurrently with requests for best-path virtual connections. In a preferred tag allocation step for point-to-multipoint tagged virtual connections, edge switches 10 , 40 and combination switch 50 , as source switches, initiate requests for forwarding broadcast, multicast and unknown unicast messages to one another as destination switches. A tagged point-to-multipoint virtual connection is requested for each VLAN shared by the source switch. Each source switch generates a set of tag allocation requests encoded with the identifier of the source switch, the shared VLAN identifier, and a first set of tag values. The set of tag allocation requests is forwarded to a set of neighboring transit or combination switches on the spanning tree path to the set of destination switches belonging to the shared VLAN. The set of neighboring switches responds by generating and forwarding a second set of tag allocation requests encoded with the identifier of the source switch, the shared VLAN identifier, and a second set of tag values. The set of tag allocation requests is forwarded to a second set of neighboring switches, if any, on the spanning tree path to the set of destination switches. Similar messages are generated and forwarded by additional sets of neighboring switches, if any, on the spanning tree path, until a set of tag allocation requests is received by the set of destination switches belonging to the shared VLAN. Switches along the path of the requested point-to-multipoint virtual connections store the tag allocation information in memory. On the source switch, the shared VLAN identifier, the first set of forwarding ATM port identifiers and the first set of tag values are stored as associated pairs in a memory means. On the neighboring switches, the inbound set of tag values encoded in the received tag allocation requests are associated with a set of forwarding ATM port identifiers and an outbound set of tag values and stored as associated pairs in forwarding databases. On the set of destination switches, the shared VLAN identifier, the set of receiving ATM port identifiers and the inbound set of tag values encoded in the set of received tag allocation requests are stored as associated pairs in receiving databases. In a more preferred tag allocation step, multiple tag allocation requests are encoded in a single tag allocation message. In a preferred message forwarding step for point-to-point tagged virtual connections, end-user messages are forwarded on the established point-to-point virtual connections. On the source switch, the destination switch identifier associated with an end-user message is resolved to a forwarding ATM port identifier and a first tag value retrieved from a memory means. The message is encoded with the first tag value and forwarded over the forwarding ATM port to a neighboring switch. The neighboring switch retrieves from a forwarding database a forwarding ATM port identifier and second tag value associated with the first tag value. The neighboring switch generates a message encoded with the second tag value and forwards the message over the forwarding ATM port to a second neighboring switch, if any. Similar messages are generated and forwarded by additional neighboring switches, if any, on the best path, until the end-user message arrives at the destination switch. In a preferred message forwarding step for point-to-multipoint tagged virtual connections, end-user messages are forwarded on the established point-to-multipoint virtual connections. On the source switch, a broadcast, multicast or unknown unicast end-user message to be forwarded to the switches belonging to the shared VLAN is resolved to a first set of forwarding ATM port identifiers and a first set of tag values retrieved from a memory means. Copies of the message are made, as necessary, and encoded with the first set of tag values and forwarded over the first set of forwarding ports to a first set of neighboring switches. The neighboring switches retrieve from a forwarding database a second set of forwarding ATM port identifiers and a second set of tag values associated with the first set of tag values. The neighboring switches generate a second set of messages encoded with the second set of tag values and forward the messages over the second set of forwarding ATM ports to a second set of neighboring switches, if any. Similar messages are generated and forwarded by additional sets of neighboring switches, if any, on the spanning tree path, until the end-user messages arrive at the set of destination switches belonging to the shared VLAN. It will be appreciated that prior to forwarding messages must be segmented into a series of fixed-length cells in accordance with governing ATM standards. A preferred message forwarding step may be further illustrated by example by reference to FIG. 1 . For simplicity, it will be assumed that a single VLAN is active on all switch ports in network 1 . It will also be assumed that links 12 , 24 , 25 have a bandwidth of 100 megabits per second and that links 23 , 35 have a bandwidth of 1 gigabit per second and that all links are enabled. It will further be assumed that stations S.sub. 1 , S.sub. 4 and S.sub. 5 have been assigned unique media access control (MAC) addresses s.sub. 1 , s.sub. 4 and S.sub. 5 , respectively, and that the MAC addresses are only known to the particular switch disposed between the stations and the ATM cloud 60 . Thus, addresses s.sub. 1 , s.sub. 4 are unknown to switch 50 , addresses s.sub. 4 , s.sub. 5 are unknown to switch 10 and addresses s.sub. 1 , s.sub. 5 are unknown to switch 40 . First, consider an end-user message originating on source station S.sub. 1 intended for destination station S.sub. 5 . At station S.sub. 1 , the message is encoded with source address s.sub. 1 and unicast destination address s.sub. 5 and propagated on LAN segment 14 . The message arrives at source switch 10 due to the broadcast nature of LAN segment 14 . Source switch 10 , however, is unable to resolve address s.sub. 5 to a point-to-point tagged virtual connection to destination switch 50 . Therefore, source switch 10 resolves the message to the point-to-multipoint tagged virtual connection associated with the active VLAN. Accordingly, value t.sub.v associated with the spanning tree path to destination switches 40 and 50 is encoded in the message. The message is segmented into a series of ATM cells and forwarded on forwarding link 12 over the forwarding ATM port on source switch 10 . Upon arrival at neighboring switch 20 , the tag value t.sub.v encoded in the message is resolved to tag values t.sub.v′ and the forwarding ATM port associated with link 23 , which is on the spanning tree path to destination switches 40 , 50 . The message is encoded with tag value t.sub.v′ and forwarded on link 23 to neighboring switch 30 . Upon arrival at neighboring switch 30 , the tag value t.sub.v′encoded in the message is resolved to tag values t.sub.v″, t.sub.v′″ and the forwarding ATM port associated with links 24 , 35 , which are on the spanning tree path to destination switches 40 , 50 , respectively. One copy of the message is encoded with tag value t.sub.v″ and forwarded on link 24 to destination switch 40 . A second copy. of message is encoded with tag value t.sub.v ′″ and forwarded on link 35 to destination switch 50 . It will be appreciated that on neighboring switches 20 , 30 , the tag resolution process can be advantageously carried out by performing a table look-up operation using custom logic. Upon arrival at destination switch 50 , switch 50 performs a source learning operation which associates source station address s.sub. 1 with source switch 10 . The source learning process results in address s.sub. 1 becoming associated in a forwarding database with a forwarding ATM port identifier and a tag value t.sub. 1 for a point-to-point tagged virtual connection to switch 10 . Switch 50 also determines whether destination address s.sub. 5 is associated with a LAN segment immediately interconnected to switch 50 . Because destination address s.sub. 5 is associated with LAN segment 54 , the message is forwarded on LAN segment 54 and arrives at destination station S.sub. 5 . Upon arrival at destination switch 40 , switch 40 performs a source learning operation which associates source station address s.sub. 1 with source switch 10 . The source learning process results in address s.sub. 1 becoming associated in a forwarding database with a forwarding ATM port identifier and a tag value t.sub. 1 for a point-to-point tagged virtual connection to switch 10 . Now consider a reply end-user message originating on source station S.sub. 5 intended for destination station S.sub. 1 . At station S.sub. 5 , the message is encoded with source address s.sub. 5 and unicast destination address s.sub. 1 and propagated on LAN segment 54 . The message arrives at source switch 50 due to the broadcast nature of LAN segment 54 . Due to the source learning operation performed on the previous end-user message, source switch 50 is able to resolve address s.sub. 1 to a point-to-point tagged virtual connection to destination switch 10 . Accordingly, value t.sub. 1 associated with the best path to destination switch 10 is encoded in the message. The message is segmented into a series of ATM cells and forwarded on forwarding link 35 over the forwarding ATM port on source switch 50 . It will be appreciated that the address resolution process can be carried out on source switch 50 by performing a table look-up operation using custom logic. Upon arrival at neighboring switch 30 , the tag value t.sub. 1 ′ encoded in the message is resolved to tag values t.sub. 1 ′ and the forwarding ATM port associated with link 23 , which is on the best path to destination switch 10 . The message is encoded with tag value t.sub. 1 ′ and forwarded on link 23 to neighboring switch 20 . Upon arrival at neighboring switch 20 , the tag value t.sub. 1 ′ encoded in the message is resolved to tag value t.sub. 1 ″ and the forwarding ATM port associated with link 12 , which is on the best path to destination switch 10 . The message is encoded with tag value t.sub. 1 ″ and forwarded on link 12 to destination switch 10 . Upon arrival at destination switch 10 , switch 10 associates source station address s.sub. 5 with source switch 50 . Switch 10 also determines whether the destination address s.sub. 1 is associated with a LAN segment immediately connected to switch 10 . Because the destination address s.sub. 1 is associated with LAN segment 14 , the message is forwarded on LAN segment 14 and arrives at destination station S.sub. 1 . Custom logic look-up operations are contemplated for tag resolution on switches 30 , 20 , 10 . Now consider how the same reply message reaches destination switch S.sub. 1 in the event link 35 is disabled. At station S.sub. 5 , the message is encoded with source address s.sub. 5 and unicast destination address s.sub. 1 and propagated on LAN segment 54 . The message arrives at source switch 50 due to the broadcast nature of LAN segment 54 . Due to the source learning operation performed on the previous end-user message, source switch 50 is able to resolve address s.sub. 1 to a point-to-point tagged virtual connection to destination switch 10 . However, since link 35 is disabled, value t.sub. 1 nb associated with the next-best path to destination switch 10 is encoded in the message. The message is segmented into a series of ATM cells and forwarded on forwarding link 25 over the forwarding ATM port on source switch 50 . Upon arrival at neighboring switch 20 , the tag value t.sub. 1 nb encoded in the message is resolved to tag value t.sub. 1 nb′and the forwarding ATM port associated with link 12 , which is on the next-best path to destination switch 10 . The message is encoded with tag value t.sub. 1 nb′and forwarded on link 12 to destination switch 10 . Source learning and forwarding on destination switch 10 proceeds in the manner described above. It will be appreciated by those of ordinary skill in the art that the invention can be embodied in other specific forms without departing from the spirit or essential character hereof. The present description is therefore considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the appended claims, and all changes that come within the meaning and range of equivalents thereof are intended to be embraced therein.

Methods for configuring, maintaining connectivity in and utilizing an ATM network. Neighboring switches share topology information and enable links to neighboring switches for tag switching. Point-to-point tagged virtual connections are established between switches on the best and next-best paths learned from topology information. Point-to-multipoint tagged virtual connections are established on the spanning tree path. Multiple tag allocation requests are included in a single message to preserve bandwidth. Next-best paths are established to reduce latency in event of link failure. Forwarding operations may be performed in hardware to reduce latency during message forwarding.

TECHNICAL FIELD The present disclosure generally relates to a relay, and more particularly, to a magnetic latching relay with a parallel-type magnetic circuit. BACKGROUND A relay is an automatic switch device having isolation function, widely applied in communication, automobiles, automatic control, household appliances and other fields, and is one of the most important control devices. Due to demands in energy preservation and environment protection, magnetic latching relays are applied to ever wide areas. Common relays require to be developed with magnetic latching features. Generally, for a typical clap-type relay, an iron core (or an iron yoke) is divided into two parts. A permanent magnet is connected between the two parts, to form a series-type magnetic circuit. Upon excitation of a coil, the magnetic circuit is closed, and a magnetic force generated by the permanent magnet can keep an armature in closed state. FIG. 1 is a schematic structural diagram of a magnetic circuit of a magnetic-latching-type electromagnet relay in the prior art. As shown in FIG. 1 , the magnetic circuit of the electromagnet relay includes a spring sheet 101 (which can form a part of an output circuit of the relay), an armature 102 , an iron yoke 103 , an iron core 104 , a coil 105 and a permanent magnet 106 . The iron core 104 passes through the coil 105 . The permanent magnet 106 is fixed between the iron core 104 and the iron yoke 103 . The armature 102 and the spring sheet 101 are riveted together in advance, and riveted onto the iron yoke 103 . The permanent magnet 106 generates a permanent magnetic circuit which starts from an N pole of the permanent magnet, passes through the iron core 104 , an air gap, the armature 102 , the iron yoke 103 , reaches an S pole of the permanent magnet. Upon excitation, the coil 105 generates a magnetic field which passes through the iron core 104 , the air gap, the armature 102 , the iron yoke 103 and the S-N of the permanent magnet. When the permanent magnet filed and the magnetic field generated by the coil is in the same direction, the magnetic forces will add to each other to form a force which overcomes the counter force of the spring sheet 101 , so as to cause the armature 102 and the iron core 104 to attract each other. After the excitation of the coil 105 stops, the magnetic field generated by the coil will disappear, and the permanent magnetic field will provide a retention force to keep the armature 102 and the iron core 104 in the attracted state. When a reverse current flows through the coil, the coil 105 generates a magnetic field which passes through the iron core 104 , the N-S of the permanent magnet, the iron yoke 103 and the armature 102 . Thus, the magnetic field generated by the coil is opposite to the direction of the permanent magnetic field, and weakens the permanent magnetic force. Under the “cooperation” of the counter force of the spring sheet 101 , the spring sheet 101 brings the armature 102 to be reset. Such a series-type magnetic circuit has the following defects. 1. The permanent magnet always causes the armature to be attracted to the iron core, and even though the spring sheet has a large counter force, but a pressure on the contact point at a normal-close terminal of the product is relatively small. Therefore, load capability of the fixed closed terminal is poor, and the product relay has a poor resistance against impact and vibration. 2. After the coil is excited for reset, the magnetic force of the permanent magnet still generates a strong attraction force to the armature. Therefore, it requires a large reset force to reset the armature to reset to a released state. If the magnetic force does not match the reset force, the coil may require a small setting voltage and a large resetting voltage, or the coil may fail to be reset. SUMMARY The objective of the present disclosure is to overcome the deficiency in the related art. In one aspect, the objective is to provide a magnetic latching relay with a parallel-type magnetic circuit in which two parallel permanent magnetic paths are formed, one of the paths is for providing a suitable attraction force to the armature, so as to keep balance with a counter force provided by a movable spring sheet and to achieve bistability or state switching more stably. In another aspect, the objective of the present disclosure is to provide a magnetic latching relay with a parallel type magnetic circuit in which a magnetic isolation recess is provided on the iron yoke and a cut is provided on the pole shoe of the iron core, to adjust the retention force generated by the iron core to the armature at the position of the armature, thus keeping balance between the magnitudes of resetting voltage and the setting voltage of the magnetic latching relay as much as possible. In still another aspect, the objective of the present disclosure is to improve the structure of the coil rack and the pole shoe of the iron core. Thus, on one hand, it can increase the creepage distance between the iron core and the fixed spring sheet, preventing electrical accidents caused by unwanted conduction of the movable contact point and the fixed contact point due to accumulation of metal spatters of the contact points. On the other hand, it can significantly improve the impact resistance of the relay. In yet still another aspect, the objective of the present disclosure is to improve the structure of the bobbin of the coil rack, to effectively isolate the first circle of an enameled wire and the last circle of the enameled wire, avoiding defects in the related art which are caused by placing the first circle of the enameled wire and the last circle of the enameled wire together. The technical solutions of the present disclosure for solving the technical problems are as follows. A clapper relay, including a magnetic circuit portion and a movable spring portion, characterized in that, the magnetic circuit portion includes an iron core, an armature, an iron yoke, a permanent magnet, a magnetic conductor member, a coil and a coil rack; the iron yoke is L shaped, formed by a first yoke parallel to the iron core and a second yoke perpendicular to the iron core; the coil is wound on the coil rack, the iron core passes through the coil rack, a lower end of the iron core is secured to the second yoke; the armature is movably mounted to a hinge portion of the iron yoke, an air gap is formed between one end of the armature and an upper end of the iron core; one end of the magnetic conductor member is connected to the first yoke, the other end of the magnetic conductor member is connected to first yoke through the permanent magnet; the movable spring portion includes a movable spring sheet and a movable contact point, the movable spring sheet formed with a first side and a second side, an elastically bendable angle is formed between the first side and the second side; the armature is secured to the second side, the first yoke is secured to the first side, the armature is flexibly connected to the first yoke via the movable spring sheet; the movable contact point is secured to the second side, wherein the permanent magnet and the magnetic conductor member, the first yoke, the second yoke, the iron core and the armature form two parallel permanent magnetic paths; the coil and the iron core form a control magnetic path, to control the opening and closing of the air gap; the permanent magnetic paths provide a force to maintain the air gap to be closed; the movable spring sheet provides a counter force to maintain the air gap to be opened. According to an embodiment of the present disclosure, at least one magnetic isolation portion is provided on the first yoke which is between a joint of the first yoke and the permanent magnet and a joint of the first yoke and the magnetic conductor member, the magnetic isolation portion is configured to increase a magnetic resistance of the magnetic circuit portion, and to adjust balance between magnitudes of setting voltage and resetting voltage of the relay by adjusting an opening size of a magnetic isolation recess. According to an embodiment of the present disclosure, an upper end of the iron core is provided with a pole shoe, a cut is provided at a side of the pole shoe, a size of the cut and/or the opening size of the magnetic isolation recess can be adjusted to regulate balance between magnitudes of a setting voltage and a resetting voltage of the relay. According to an embodiment of the present disclosure, one end of the magnetic conductor member is provided with a contact surface for contacting the first yoke. According to an embodiment of the present disclosure, the contact surface of the magnetic conductor member is provided with a boss for positioning with the first yoke, the first yoke is provided with a hole for fitting with the boss of the magnetic conductor member; the boss of the magnetic conductor member is fitted in the hole of the first yoke, and secured thereto via rivet or welding. According to an embodiment of the present disclosure, the permanent magnet is secured to the other end of the magnetic conductor member, and the other end of the magnetic conductor member is provided with a bulge for securing the permanent magnet. According to an embodiment of the present disclosure, the relay further includes a fixed spring portion, the fixed spring portion includes a fixed spring sheet and a fixed contact point secured on the fixed spring sheet; an upper end plate of the coil rack extends to a side where a mounting portion is disposed, the fixed spring sheet is mounted in the mounting portion, the movable contact point is mounted at a position in the mounting portion where matches with the position of the fixed contact point; at least one shielding wall is provided on the coil rack and between the through holes and the mounting portion, to separate a pole shoe at the through hole of the coil rack and the fixed spring sheet at the mounting portion. According to an embodiment of the present disclosure, the shielding wall is disposed close to the through hole, and corresponding to the armature secured to the movable spring sheet, a height of the shielding wall is not lower than a bottom of the armature when the relay is reset, in order to prevent the armature from moving to a direction where the movable contact point contacts the fixed contact point. According to an embodiment of the present disclosure, there are provided two shielding walls, and a groove is formed between the two shielding walls for collecting spatters of the contact points, wherein one of the shielding walls is disposed close to the through hole, and corresponding to the armature secured to the movable spring sheet, a height of the shielding wall is not lower than a bottom of the armature when the relay is reset, in order to prevent the armature from moving to a direction where the movable contact point contacts the fixed contact point. According to an embodiment of the present disclosure, the shielding wall is integrated with the coil rack. According to an embodiment of the present disclosure, the coil rack includes a bobbin, one end of the bobbin is connected to a lower terminal plate, the other end of the bobbin is connected to an upper terminal plate, a first pin, a second pin and a third pin are respectively mounted on the lower terminal plate; a groove for guiding an enameled wire is provided at an inner side of the lower terminal plate which is between the bobbin and the second pin, one end of the groove is connected to the bobbin, and the other end of the groove leads to the second pin. According to an embodiment of the present disclosure, a boss is provided at an inner side of the lower terminal plate which extends from the bobbin to the second pin, a support wall is provided at a side of the boss, and the groove for guiding an enameled wire is surrounded and thus formed by the support wall and the boss. According to an embodiment of the present disclosure, an inclined plate is provided at an inner side of the lower terminal plate, the inclined plate is gradually inclined in a direction from the bobbin to the second pin; the boss and the support wall are respectively disposed at the middle of the inclined plate and a side of the inclined plate. According to an embodiment of the present disclosure, a first cover plate which can press and seize the enameled wire is mounted at the inner side of the lower terminal plate and between the first pin and the bobbin. According to an embodiment of the present disclosure, neither of an upper surface of the boss and an upper surface of the support wall is higher than an upper surface of the first cover plate. According to an embodiment of the present disclosure, a second cover plate which can press and seize the enameled wire is mounted at the inner side of the lower terminal plate and between the third pin and the bobbin. According to an embodiment of the present disclosure, neither of the upper surface of the boss and the upper surface of the support wall is higher than an upper surface of the second cover plate. It can be seen from the above description of the present disclosure that, compared with related art, the present disclosure has the following advantageous effects. According to an embodiment, due to the effect of the magnetic conductor member, the magnetic flux generated by the permanent magnet is divided into two paths and both of the two paths of magnetic fluxes are adjustable. Thereby, it can solve the problem that in the series-type magnetic circuit, there is only one path which cannot be adjusted, and the permanent magnet in the resetting position will keep a large attraction force to the armature and reduce the pressure on the contact points of the normal-close terminal and weaken the load capability of the fixed closed terminal and the product relay has a poor resistance against impact and vibration. According to an embodiment, the first yoke is provided with a magnetic isolation recess for increasing the magnetic resistance of the magnetic circuit, and a portion of the pole shoe of the iron core is cut off. The size of area of the cut (the portion cut off) can be adjusted to, together with the magnetic isolation recess, regulate the balance between the magnitudes of the setting voltage and resetting voltage of the relay. The size of the magnetic isolation recess of the iron yoke can be adjusted to regulate the balance between the magnitudes of the setting voltage and resetting voltage of the relay. However, the magnetic isolation recess cannot be increased infinitely. That is, the magnetic conduction cross sectional area at either side of the magnetic isolation recess cannot be reduced infinitely. Therefore, the magnitudes of the setting voltage and the resetting voltage of the relay cannot be regulated without limit. For a magnetic latching relay, it is generally desirable to make the resetting voltage to be approximate to the setting voltage as much as possible. Therefore, in order to increase the resetting voltage, in the prevent disclosure, a portion of the pole shoe of the iron core is cut off. According to a magnetic circuit principle, the smaller the area of the pole shoe of the iron core is, the larger the retention force (the magnetic attraction force) on the armature when the armature is at the setting position is, and the larger the resetting voltage required is. Accordingly, the magnitudes of the resetting voltage and the setting voltage can be balanced (to make the resetting voltage to be approximate to the setting voltage in the value) as much as possible. According to an embodiment, a shielding wall is provided on the coil rack between the fixed spring sheet and the iron core. After the movable contact point and the fixed contact point are burned, metal spatters of the movable contact point and the fixed contact point can be blocked by the shielding wall, to prevent the metal spatters from drifting from the contact points to the iron core. A groove formed between the two shielding walls and a region between the shielding wall and the fixed contact point can also be configured to collect the metal spatters of the contact points. Thereby, the creepage distance between the movable contact point and the fixed contact point as well as the dielectric Strength can be improved, and it can effectively prevent electrical accidents caused by unwanted conduction of the movable contact point and the fixed contact point due to accumulation of metal spatters of the contact points. The shielding wall is disposed close to the through hole, and corresponding to the armature which is secured to the movable spring sheet. The height of the shielding wall is not lower than the bottom of the armature when the relay is reset. When the relay is subject to an impact in a length direction, the armature will move toward the contact points. Due to the presence of the shielding wall, the armature is limited in the length direction. Thus, the armature and the movable contact point will not displace from normal positions due to the impact, significantly improving the impact resistance of the relay. According to an embodiment, a groove for guiding the enameled wire is surrounded and thus formed by a boss and a support wall. The bottom of the groove is an inclined plate. One end of the groove is connected to the bobbin, one end of the groove leads to the second pin. Thus, in winding the first circle of the outer circles of the enameled wire, the enameled wire is placed on the inclined plate. In winding the last circle of the outer circles of the enameled wire, due to the effect of the boss and the support wall, the last circle of the enameled wire can be held up, to form an air gap between the first circle of the enameled wire and the last circle of the enameled wire, thus avoiding an unfavorable situation of the first circle and the last circle being directly placed together in winding the out circles. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic structural diagram of a magnetic circuit portion of a magnetic-latching-type electromagnet relay in the prior art; FIG. 2 is an exploded view of the configuration according to an embodiment of the present disclosure; FIG. 3 is a schematic structural diagram of a magnetic circuit portion according to an embodiment of the present disclosure; FIG. 4 is a schematic structural diagram of an iron yoke of the magnetic circuit portion according to an embodiment of the present disclosure; FIG. 5 is a schematic structural diagram of an iron yoke of the magnetic circuit portion according to an embodiment of the present disclosure, with one portion removed; FIG. 6 is a schematic structural diagram of a magnetic conductor member of the magnetic circuit portion according to an embodiment of the present disclosure; FIG. 7 is a side view of the magnetic conductor member of the magnetic circuit portion according to an embodiment of the present disclosure; FIG. 8 is a schematic structural diagram of an iron core of the magnetic circuit portion according to an embodiment of the present disclosure; FIG. 9 is a top view of an iron core of the magnetic circuit portion according to an embodiment of the present disclosure; FIG. 10 is a schematic circuit diagram of the magnetic circuit portion according to an embodiment of the present disclosure, in a resetting state and when the coil is powered off; FIG. 11 is a schematic circuit diagram of the magnetic circuit portion according to an embodiment of the present disclosure, in a resetting state and when the coil is powered with a setting voltage; FIG. 12 is a schematic circuit diagram of the magnetic circuit portion according to an embodiment of the present disclosure, in a setting state and when the coil is powered off; FIG. 13 is a schematic circuit diagram of the magnetic circuit portion according to an embodiment of the present disclosure, in a setting state and when the coil is powered with a resetting voltage; FIG. 14 is a cross sectional view of an embodiment of the present disclosure; FIG. 15 is a schematic structural diagram of a coil rack according to an embodiment of the present disclosure, mainly showing an upper end plate; FIG. 16 is a top view of the coil rack according to an embodiment of the present disclosure, mainly showing an upper end plate; FIG. 17 is a schematic diagram of the coil rack according to an embodiment of the present disclosure, with an iron core and a fixed spring assembled; FIG. 18 is a partial structural diagram of an armature and contact mechanism according to an embodiment of the present disclosure; FIG. 19 is a perspective diagram of a coil rack according to an embodiment of the present disclosure; FIG. 20 is a schematic diagram of a coil rack when winding inner circles of an enameled wire according to an embodiment of the present disclosure; FIG. 21 is a schematic diagram of a coil rack when winding outer circles of an enameled wire according to an embodiment of the present disclosure; FIG. 22 is a side view of a coil rack when winding outer circles of an enameled wire according to an embodiment of the present disclosure; and FIG. 23 is a schematic diagram of a coil rack when inner circles and outer circles of an enameled wire have been wound according to an embodiment of the present disclosure. DETAILED DESCRIPTION Representative embodiments showing characteristics and advantages of the present disclosure will be described in detail in the following description. It should be understood that, the present disclosure can be varied with various embodiments without departing from the scope of the present disclosure. The description and the illustration are merely for explanation, rather than for limitation of the present disclosure. Terms representing orientations, such as upper, lower, top, bottom and the like mentioned in the present disclosure are merely for illustrating relative positions between components, and not for limitation of specific assembly orientation of the components in the present disclosure. As shown in FIGS. 2-9 , an embodiment of the present disclosure provides a magnetic latching relay with a parallel type magnetic circuit, including a magnetic circuit portion 1 , a movable spring portion 2 , a fixed spring portion 3 and a base 4 . Wherein the magnetic circuit portion 1 includes an iron core 11 , an armature 12 , an iron yoke 13 , a permanent magnet 14 , a magnetic conductor member 15 , a coil rack 16 and an enameled wire 17 . The movable spring portion 2 includes a movable spring sheet 21 and a movable contact point 22 . The fixed spring portion 3 includes a fixed spring sheet 31 and a fixed contact point 32 . As shown in FIGS. 2 and 3 , the iron yoke 13 is L shaped, formed by a first yoke 131 parallel to the iron core and a second yoke 132 perpendicular to the iron core. An upper end of the first yoke 131 forms a hinge portion of the iron yoke 13 (a “hinge portion” refers to a contact portion of the iron yoke contacting with the armature rotating around the iron yoke). The armature 12 can rotate around the hinge portion of the iron yoke. The enameled wire 17 is wound on the coil rack 16 , and the coil rack 16 is mounted on the base 4 . In the present embodiment, the coil rack 16 is integrally formed with the base 4 . The coil rack 16 is provided with a through hole 161 along a vertical direction. The iron core 11 is mounted in the through hole 161 of the coil rack. The iron core 11 is provided at an upper end thereof with a pole shoe 111 , and the iron core 11 is secured to the second yoke 132 at its lower end. The armature 12 is connected to the iron yoke 13 via the movable spring sheet 21 . The movable spring sheet 21 is formed with a first side 211 and a second side 212 . An elastically bendable angle is formed between the first side 211 and the second side 212 . The armature 12 can be secured to the second side 212 through a rivet. The first yoke 131 can be secured to the first side 211 through a rivet. The armature 12 is flexibly connected to the first yoke 131 via the movable spring sheet 21 . The movable contact point can be secured to an end portion of the second side 212 which extends beyond the armature 12 . The second side 212 of the movable spring sheet is secured to the armature 12 and fitted on the upper side of the pole shoe 111 of the iron core, and the armature 12 is thus mounted at the hinge portion of the iron yoke. The magnetic conductor member 15 has one end connected with the first yoke 131 , and the other end connected to the first yoke 131 via the permanent magnet 14 . A magnetic isolation recess 133 is provide between a conjunction of the first yoke 131 and the permanent magnet 14 and the first yoke 131 and the magnetic conductor member 15 . The magnetic isolation recess 133 is for increasing the magnetic resistance of the magnetic circuit, and a size of the magnetic isolation recess 133 can be adjusted to adjust balance between the setting voltage and resetting voltage of the relay. The pole shoe 111 has a side provided with a cut 112 . Combined with the magnetic isolation recess 133 , a size of the cut 112 can be adjusted to adjust the balance between the setting voltage and resetting voltage of the relay. Now the drawing only shows one magnetic isolation recess 133 , however two magnetic isolation recesses 133 can be implemented as long as a cross section area of solid portion of the first yoke 131 can be adjusted. The magnetic isolation recess 133 can be replaced with other magnetic isolation configuration, such as a pillar member or the like. In the present embodiment, the cut 112 of the pole shoe 111 is a full circular shape with one portion cut off (as shown in FIG. 9 ), the full circular shape being symmetric with respect to the central axis of the iron core. However, alternatively, the cut of the pole shoe can be a full rectangle with one portion cut off, the full rectangle being symmetric with respect to the central axis of the iron core. The cut 112 of the pole shoe 111 is disposed toward a direction in which the movable contact point and the fixed contact point are to be attracted to each other (as shown in FIG. 2 ). Thereby, a creepage distance between the iron core and the fixed spring sheet can be increased. A creepage distance is a “distance” measured along an insulated surface between two conductive components. As shown in FIGS. 3, 6 and 7 , the magnetic conductor member 15 is at one end provided with a contact surface 151 for contacting the first yoke 131 . The contact surface 151 of the magnetic conductor member is provided with one or more bosses 152 for positioning of the first yoke. The first yoke 131 is provided thereon with holes 1311 fitted with the bosses of the magnetic conductor member. The bosses 152 of the magnetic conductor member is fitted within the holes 1311 of the first yoke 131 , and secured with them via a rivet or weld. The permanent magnet 14 is secured to the other end of the magnetic conductor member 15 . The magnetic conductor member is provided at the other end with bosses 153 for securing the permanent magnet. FIGS. 10-13 are schematic circuit diagrams of the relay when the relay is respectively powered off, powered with a setting voltage, when the coil is powered with a resetting voltage. Φm1, Φm2 denote magnetic fluxes (referred to as permanent magnet fluxes, generally represented by Φm) generated by the permanent magnet 14 . The paths passed by the permanent magnet fluxes are respectively referred to as a first magnetic path A 1 and a second magnetic path A 2 . Φc1, Φc2 denote magnetic fluxes (referred to as control magnet fluxes, generally represented by Φc) generated by current in the coil, and the path passed by the control magnet fluxes is referred to as a third magnetic path A 3 . Wherein, Φc1 is a magnetic flux generated by current of the coil under a setting voltage, and Φc2 is a magnetic flux generated by current of the coil under a resetting voltage. δ2 denotes an operation air gap, and F2 denotes an electromagnetic attraction force (generally represented by F) applied on the armature at the air gap δ2. The magnetic circuit has two stable states, that is, the armature 12 being at the setting position or at the resetting position. When the armature 12 is in the resetting state (the armature 12 is at an opened position, and the coil is not supplied with current) as shown in FIG. 10 , due to the effects of the magnetic conductor member 15 and the magnetic isolation recess 133 , the magnetic flux generated by the permanent magnet 14 passes through paths of the first magnetic path A 1 and the second magnetic path A 2 as shown in the figure. The magnetic fluxes denoted by Φm1 and Φm2 are parallel. On the second magnetic path A 2 , due to the influence of the air gap δ2, Φm2 has a small effect. Therefore, at this time, the armature 12 is subject to a weak electromagnetic attraction force F2 under the effect of Φm2, which is smaller than a counter force F1 applied by the movable spring sheet 21 on the armature 12 , that is, F1>F2. Then, under the counter action of the counter force of the movable spring sheet 21 , the armature 12 can be stably maintained at the resetting position (i.e. the opened position). Due to the effects of the magnetic conductor member 15 and the magnetic isolation recess 133 , the magnetic flux generated by the permanent magnet 14 are divided into magnetic fluxes Φm1 and Φm2 of two paths, and the magnitudes of the magnetic fluxes Φm1 and Φm2 can be adjusted. Thereby, it can solve the problem in the series-type magnetic circuit, there is only one path which cannot be adjusted, and the permanent magnet in the resetting position will keep a large attraction force to the armature and reduce the pressure on the contact points of the normal-close terminal and weaken the load capability of the fixed closed terminal and the product relay has a poor resistance against impact and vibration. As shown in FIG. 11 , when a resetting pulse voltage with a certain width is applied on the coil of the relay, a control magnetic flux Φc1 generated by the coil of the relay has a direction as shown by a third magnetic path A 3 in FIG. 11 . At this time, the magnetic flux Φc1 generated by the coil and the magnetic flux Φm2 generated by the permanent magnet 14 have the same direction (as shown by a second magnetic path A 2 in FIG. 11 ). This increases a composite magnetic flux at the air gap δ2. Therefore, the armature 12 is subject an increased electromagnetic attraction force F2 due to the effect of the composite magnetic flux of Φc1 and Φm2. When the electromagnetic attraction force F2 subjected by the armature 12 is larger than the counter force F1 applied by the movable spring sheet 21 on the armature 12 , the armature 12 will complete an action moving from the resetting position to the setting position under the composite force of F2 and F1. Afterwards, after the operation current of the coil is powered off, the electromagnetic attraction force F2 generated by the magnetic flux Φm2 of the permanent magnet 14 is larger than the counter force F1 applied by the movable spring sheet 21 on the armature 12 . Then, the armature 12 will be stably maintained in the setting position, as shown in FIG. 12 . When the relay is at the setting position as shown in FIG. 12 , a resetting pulse voltage (opposite to the setting voltage) with a certain width is applied to the coil of the relay, a control magnetic flux Φc2 generated by the coil of the relay has a direction as shown in FIG. 13 . At this time, the magnetic flux Φc2 generated by the coil and the magnetic flux Φm2 generated by the permanent magnet 14 have opposite directions (as shown by the second magnetic path A 2 and the third magnetic path A 3 in FIG. 13 ). Thereby, the magnetic flux Φm2 generated by the permanent magnet 14 is counteracted. Therefore, at this time, electromagnetic attraction force F2 subjected by the armature 12 is decreased due to the effects of Φc2 and Φm2. When the electromagnetic attraction force F2 subjected by the armature 12 is smaller than the counter force F1 applied by the movable spring sheet 21 on the armature 12 , the armature 12 will complete an action moving from the setting position to the resetting position under the composite force of F2 and F1, and return to the resetting position as shown in FIG. 10 . FIG. 12 shows magnetic fluxes of the magnetic circuit when the armature is at the setting position and the coil is powered off. The permanent magnet 14 has two paths of magnetic fluxes Φm1 and Φm2. The total flux of the permanent magnet 14 (Φmtotal)=Φm1+Φm2. By adjusting the size of the magnetic isolation recess 133 , a magnetic conduction cross sectional area 1331 at either side of the magnetic isolation recess 133 of the yoke (as shown in FIG. 5 ) changes and thus a magnetic resistance of the first magnetic path A 1 changes, to form a changed first magnetic fluxe Φm1. Since the total flux(Φmtotal) is substantially constant, and Φm2=(Φmtotal)−Φm1, when (Φm1 changes, Φm2 will change too (in an opposite direction of value variation). When Φm2 changes, the electromagnetic attraction force F2 generated by the permanent magnet 14 through the second magnetic path A 2 , which attracts the armature 12 on the pole shoe of the iron core, will change. That is, the retention force to keep the armature 102 against the pole shoe of the iron core changes, to solve the problem that it is hard to reset in the series-type magnetic circuit. Due to the effect of the magnetic conductor member 15 and the magnetic isolation recess 133 , the magnetic flux generated by the permanent magnet 14 is divided into two paths Φm1 and Φm2, and the magnitudes of Φm1 and Φm2 can be adjusted, to solve the problem that in the series-type magnetic circuit, there is there is only one path which cannot be adjusted, causing difficulty in resetting. When the coil of the relay is applied with a resetting pulse voltage (opposite to the setting voltage) with a certain width, the magnetic flux Φc2 generated by the coil will be counteracted by the magnetic flux Φm2 generated by the permanent magnet 14 . When the composite magnetic flux (Φm2−Φc2) is reduced to a degree that the electromagnetic attraction force F2 generated by composite magnetic flux to the armature 12 is smaller than the counter force F1 applied by the movable spring sheet 21 on the armature 12 , the armature 12 will complete an action moving from the setting position to the resetting position under the composite force of F2 and F1. As discussed above, since the size of the magnetic isolation recess 133 can be provided differently, to form a different Φm2. While the electromagnetic attraction force F2 is generated by the composite magnetic flux (Φm2-Φc2), therefore, under a different Φm2, to reduce the electromagnetic attraction force F2 to a value smaller than the counter force F1, the value of Φc2 should be changed. Since Φc2 is generated by applying a voltage on the coil, changing the size of the magnetic isolation recess 133 will change the magnitude of Φm2, and in turn, change the magnitude of the resetting voltage for resetting the armature. In the magnetic circuit of the present invention, in order to ensure a certain strength of the components, the magnetic conduction cross sectional area 1331 (as shown in FIG. 5 ) at either side of the magnetic isolation recess 133 of the yoke cannot be reduced infinitely. Therefore, Φm2 cannot be too large, and generally a small resetting voltage can be applied to obtain an electromagnetic attraction force F2, as generated by the composite magnetic flux (Φm2-Φc2), smaller than the counter force F1, to reset the armature. For a magnetic latching relay, it is desirable to make the resetting voltage to be approximate to the setting voltage as much as possible. Therefore, in order to increase the resetting voltage, in the prevent disclosure, half of the pole shoe of the iron core is cut off (according to a magnetic circuit principle, the smaller the area of the pole shoe of the iron core is, the larger the retention force (the magnetic attraction force F2) on the armature when the armature is at the setting position is, and the larger the resetting voltage required is), so as to balance the resetting voltage and the setting voltage (to make the resetting voltage to be approximate to the setting voltage in the value) as much as possible. An embodiment regarding the coil rack 16 and the fixed spring portion 3 in the relay will be described below. As shown in FIG. 2 and FIG. 14 , the fixed spring portion 3 includes the fixed spring sheet 31 and the fixed contact point 32 fixed on the fixed spring sheet 31 . The fixed spring sheet 31 is mounted at a position which allows the movable contact point and the fixed contact point to contact each other. The coil rack 16 includes an upper terminal plate 160 , a bobbin 167 and a lower terminal plate 168 . The upper terminal plate 160 of the coil rack 16 extends to a side, and a mounting portion 162 is disposed at the side. The fixed spring sheet 31 and the fixed contact point 32 are embedded in the mounting portion 162 . The movable contact point 22 is mounted at a position in the mounting portion 162 where matches with the position of the fixed contact point 32 (as shown in FIGS. 15-17 ). At least one shielding wall 163 , 164 is provided on the coil rack 16 and between the though hole 161 and the mounting portion 162 . The shielding wall 163 , 164 is formed as one piece with the coil rack 16 , to separate the pole shoe 11 at the through hole of the coil rack and the fixed spring sheet 31 at the mounting portion. In the present embodiment, as shown in FIG. 14 and FIG. 18 , there are two shielding walls 163 and 164 . A groove 165 is formed between the shielding walls 163 and 164 to collect spatters of the contact points. Wherein one shielding wall 163 is disposed close to the through hole 161 , and corresponding to the armature 12 of the movable spring sheet. The height of the shielding wall 163 is not lower than the bottom of the armature 12 when the relay is reset, in order to prevent the armature 12 from moving to the direction where the movable contact point contacts the fixed contact point. There can be provided one shielding wall. When there is only one shielding wall, the shielding wall is disposed close to the through hole, and corresponding to the armature of the movable spring sheet. The height of the shielding wall is not lower than the bottom of the armature when the relay is reset, in order to prevent the armature from moving to the direction where the movable contact point contacts the fixed contact point. A cut 112 is provided at a side of the pole shoe 111 where close to the fixed spring sheet 31 . Thus, the creepage distance between the pole shoe and the fixed spring sheet is increased by a distance of the cut 112 . Thereby, the creepage distance between the pole shoe of the iron core and the fixed spring sheet can be increased. Also referring to FIGS. 15-17 , shielding walls 163 and 164 are provided on the coil rack and between the fixed spring sheet 31 and the iron core 11 . After the movable contact point and the fixed contact point are burned, metal spatters of the movable contact point and the fixed contact point can be blocked by the shielding wall, to prevent the metal spatters from drifting from the contact points to the iron core. The groove 165 formed between the two shielding walls and a region 166 between the shielding wall 164 and the fixed contact point 32 can also be configured to collect the metal spatters of the contact points. Thereby, the creepage distance between the movable contact point and the fixed contact point as well as the dielectric Strength can be improved, and it can effectively prevent electrical accidents caused by unwanted conduction of the movable contact point and the fixed contact point due to accumulation of metal spatters of the contact points. The shielding wall 163 is disposed close to the through hole 161 , and corresponding to the armature 12 which is secured to the movable spring sheet. The height of the shielding wall 163 is not lower than the bottom of the armature 12 when the relay is reset. When the relay is subject to an impact in a length direction, the armature 12 will move toward the contact points. Due to the presence of the shielding wall 163 , the armature 12 is limited in the length direction. Thus, the armature 12 and the movable contact point 22 will not displace from normal positions due to the impact, significantly improving the impact resistance of the relay. The above configuration can expand the application range of the relay. As shown in FIGS. 19-23 , an embodiment of the present disclosure provides a coil rack of a double-coil relay. One end of the bobbin 167 is connected to the upper terminal plate 160 , the other end of the bobbin 167 is connected to the lower terminal plate 168 . A first pin 51 , a second pin 52 and a third pin 53 are respectively mounted on the lower terminal plate 168 . The lower terminal plate 168 can be integrated with the base 4 . A groove 1684 is provided at an inner side of the lower terminal plate 168 between the bobbin 167 and the second pin 52 , to guide the enameled wire. One end of the groove 1684 can be connected to the bobbin 167 , and the other end of the groove can lead to the second pin 52 . An inclined plate 1681 is provided at an inner side of the lower terminal plate 168 , and located between the bobbin 167 and the second pin 52 . The inclined plate 1681 is gradually inclined in a direction from the bobbin to the second pin. A boss 1682 extending from the bobbin to the second pin is provided in the middle of the inclined plate 1681 . That is, the boss 1682 is provided on the inclined plate 1681 , and the boss 1682 is a boss with a flat surface. A support wall 1683 is provided at a side of the inclined plate 1681 . The support wall 1683 is also provided on the inclined plate 1681 , and an upper surface of the support wall 1683 is also flat. The groove 1684 for guiding the enameled wire is surrounded and thus formed by the support wall 1683 and the boss 1682 . The bottom of the groove 1684 is an inclined plate. The height of the boss 1682 is the same as the height of the support wall 1683 . However, the height of the boss 1682 can be different from the height of the support wall 1683 . A first cover plate 1685 which can press and seize the enameled wire is mounted at the inner side of the lower terminal plate 168 and between the first pin 51 and the bobbin 167 . That is, the first cover plate 1685 is provided at the inner side of the lower terminal plate 168 , and located between the bobbin 167 and the first pin 51 . In the present embodiment, the upper surface of the first cover plate 1685 , the upper surface of the boss 1682 and the upper surface of the support wall 1683 are in the same horizontal plane. However, the upper surface of the first cover plate 1685 can also be disposed as higher than the upper surface of the boss 1682 and the upper surface of the support wall 1683 . A second cover plate 1686 which can press and seize the enameled wire is mounted at the inner side of the lower terminal plate 168 and between the third pin 53 and the bobbin 167 . That is, the second cover plate 1686 is provided at the inner side of the lower terminal plate 168 , and located between the bobbin 167 and the third pin 53 . In the present embodiment, the upper surface of the second cover plate 1686 , the upper surface of the boss 1682 and the upper surface of the support wall 1683 are in the same horizontal plane. However, the upper surface of the second cover plate 1686 can also be disposed as higher than the upper surface of the boss 1682 and the upper surface of the support wall 1683 . As shown in FIGS. 20-23 , the present embodiment provides a coil rack of a double-coil relay. To wind the enameled wire, the enameled wire are firstly wound from inner circles. After the enameled wire 17 is firstly wound on the first pin 51 , the enameled wire 17 passes below the first cover plate 1685 . After the enameled wire 17 is wound on the bobbin 167 anticlockwise for a required number of circles, the enameled wire 17 passes through the groove 1684 and leads to the second pin 52 . After the enameled wire 17 is wound on the second pin 52 , winding of the inner circles of the enameled wire 17 is completed. In winding of the outer circles, after the enameled wire 17 is wound on the second pin 52 , a first circle 171 of the enameled wire passes through the groove 1684 and leads to the bobbin 167 . After the enameled wire is wound on the bobbin 167 clockwise for a required number of circles, the last circle 172 of the enameled wire passes through the boss 1682 , the support wall 1683 and leads to the below part of the second cover plate 1686 . After the enameled wire passes through the below part of the second cover plate 1686 , and is wound on the third pin 53 , the winding of the outer circles is completed. The boss 1682 and the support wall 1683 form the groove 1684 which can guide the enameled wire; the bottom of the groove is an inclined plate; one end of the groove is connected to the bobbin; and the other end of the groove leads to the second pin. Thereby, in winding the first circle 171 of the outer circles of the enameled wire, the enameled wire is placed on the inclined plate 1681 . In winding the last circle 172 of the outer circles of the enameled wire, due to the effect of the boss 1682 and the support wall 1683 , the last circle 172 of the enameled wire can be held up, to form an air gap 173 between the first circle 171 of the enameled wire and the last circle 172 of the enameled wire, thus avoiding an unfavorable situation of the first circle and the last circle being directly placed together in winding the out circles. The above is an embodiment of the coil rack 16 , and is not exclusively applied to the above magnetic latching relay with a paralleltype magnetic circuit. The coil rack 16 can also be applied in other types of relays by those skilled in the art. Although the present disclosure has been described with reference to some exemplary embodiments, it should be understood that the terms are not restrictive, but illustrative and exemplary. The present disclosure can be embodied in various forms without departing from the spirit or essence thereof. Therefore, it can be understood that the above embodiment is not limited to the above details, but should be interpreted broadly within the spirit and scope defined by the appending claims. In this regard, all alterations and modifications falling within the claims or their equivalent scope should be covered by the appending claims.

A magnetic latching relay of a parallel type magnetic circuit, forming two parallel permanent magnetic circuits on the permanent magnetic circuit of a relay; one of the permanent magnetic circuits is used to provide adequate attraction to an armature, so that permanent magnetic attraction can achieve a balance of applied forces with the counter-force provided by a movable spring, so as to realize relay bistability or state transition more stably.

CROSS-REFERENCE TO RELATED APPLICATION This application claims priority of U.S. Provisional Application No. 60/216,797, entitled “INTERACTIVE DATA TRANSMISSION SYSTEM,” filed on Jul. 7, 2000, which is hereby incorporated by reference for all purposes. This application is related to U.S. application Ser. No. 09/698,701 filed on the same day, and entitled “INTERACTIVE DATA TRANSMISSION SYSTEM.” BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to real-time data transmission across a network. More particularly, the present invention relates to real-time transmission of data and interactive modification of the data transmitted across a network in response to a request received from a network device over the network. 2. Description of Related Art A popular pasttime in today's entertainment-oriented society is watching movies. In fact, many movie fanatics have acquired elaborate home entertainment systems solely for this purpose. However, for those individuals who decide to spend their Saturday night at home with a movie, there a limited number of options available to them. Traditionally, movie goers who prefer to watch movies in the privacy of their own homes rent videos from a local video rental store. However, the video rental process is a time-consuming one, requiring the movie viewer to travel from his or her home merely to obtain the desired video. Of course, even with the obvious disadvantages associated with the video rental process, many still find this desirable since they can watch the movie as many times as they want, and they may pause, rewind, fast forward, and re-start the movie at their own convenience. In view of the disadvantages associated with the conventional video rental process, pay-per-view is a viable option, particularly in hotels which often do not offer video rental services to its guests. Through the pay-per-view option, it is possible to select a video as well as view the video from the privacy of home or a hotel room. However, the movie choices typically offered to movie viewers by such cable providers are limited. Moreover, the pay-per-view option does not offer the advantages of a standard VCR. More particularly, the pay-per-view option does not allow a user to pause, rewind, fast forward, or re-start a movie once it has started. In addition, the available viewing times are typically set and therefore cannot be selected by a user. Physical tapes are also used for a variety of purposes other than viewing movies. For instance, in Asian countries, karaoke is a popular pastime. A traditional karaoke business is commonly run with a central control room connected to multiple listening stations. The control room contains a machine associated with each listening station to enable a desired tape to be played and routed to the listening station (e.g., via a coaxial cable). When a karaoke participant in one of the listening stations requests a particular karaoke song, the appropriate tape is physically inserted into the machine connected to the listening station. The karaoke tape is then played and routed to the listening station connected to this machine. The existing karaoke model is undesirable in a variety of ways. Since a machine capable of playing karaoke tapes is required for each listening station, the existing karaoke system often requires numerous machines. Since these machines are not automated, it is necessary to employ personnel that will be available to operate the machines. Due to the expense associated with acquiring and maintaining numerous karaoke machines and associated personnel, a traditional karaoke business is far from inexpensive to operate. In addition, it is typically necessary to maintain multiple copies of songs that are popularly requested in order to be able to fulfill the same song request when it is received from more than one listening station. Moreover, since multiple copies are often retained for these popular selections, the cost of maintaining an adequate inventory as well as storage space to store these copies increases the cost of such a karaoke business. In addition, the quality of a physical medium such as a video tape deteriorates over time. Moreover, since the karaoke tapes must be loaded and unloaded by humans, this type of system is susceptible to human error. As a result, the incorrect tape may be loaded or there may be a substantial delay between songs while the personnel are locating or changing the tapes. Thus, it is impossible for a karaoke participant to predict the time that a selected song will start. Similarly, it is impossible to predict the delay between songs that are loaded consecutively into the karaoke machine. It is also important to note that the karaoke singers in the listening stations do not have access do the machine associated with their private listening station. Thus, once a karaoke tape has been inserted, karaoke participants cannot interactively control their individual karaoke experience. In view of the above, it would be desirable if a system could offer the interactive nature of a VCR without the limitations and conveniences associated with a VCR. In addition, it would be beneficial if a user were provided a wide range of choices previously unavailable to a VCR or pay-per-view user. SUMMARY The present invention enables data to be transmitted over a network from a server to a client device such as a set-top box. This may be accomplished via a single local server as well as via multiple staged servers, such as from a central server via the local server. For instance, the central server may be associated with a web site on the Internet. In addition, once initiated, data flow may be modified and controlled interactively by the user. Moreover, a file may be loaded from the central server to a memory associated with the local server. This loading process may be performed in combination with data transmission upon initiation by a user (e.g., via a web browser) or by the local server when a requested file is not accessible to the local server. Alternatively, it may be desirable to load a file independently from the data transmission process. In accordance with one aspect of the invention, a first network device such as a set-top box may interactively control data flow from a second network device such as a server to the first network device. A control command indicating a desired modification to the flow of data from the second network device to the first network device is received at the first network device. The first network device sends a control command to the second network device. When the second network device receives the control command, the second network device modifies the flow of data from the second network device to the first network device in response to the control command. The first network device then receives a modified flow of data from the second network device to the first network. This process may similarly be performed across multiple staged servers rather than by a single local server. Modification to the flow of data may be accomplished by modifying a data stream in a variety of ways. For instance, modification may include initiating transmission of a data stream, pausing transmission of a data stream, advancing transmission by a single frame, modifying the speed of transmission of data, and modifying the source of the data being transmitted (e.g., file and/or file location). Such a modification to the flow of data between network devices may be initiated by a user via an input device such as a mouse, keyboard, or remote control device. In accordance with another aspect of the invention, a user may select one or more files from which data is to be transmitted over a network from a network device such as a server to another device such as a set-top box. Each of the files may include video data and audio data as well as other digital data. For instance, each file may include a movie or a karaoke video. The user may select via the set-top box one or more of a plurality of files associated with the server. In addition, the user may specify an order of transmission of the selected files. Information identifying the selected files as well as the specified order of transmission may then be sent from the set-top box to the server. Data stored in these files may then be transmitted from the server to the set-top box in the order of transmission. In accordance with another aspect of the invention, the present invention enables transmission of data to be billed within a multiple site system such as a hotel. More particularly, it is possible to bill a guest each time a movie or karaoke song is played (i.e., transmitted from the local server). Moreover, the hotel may wish to bill the guest an additional amount when the requested selection is transmitted from the central server over the Internet to the guest's hotel room (e.g., when the user accesses the central server via a web browser). Of course, it may be desirable to bill a guest once (e.g., when the associated file is loaded from the central server to the local server), allowing the guest to view the selection multiple times. BRIEF DESCRIPTION OF THE DRAWINGS The invention, together with further advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings in which: FIG. 1 is a block diagram illustrating an exemplary system in which the present invention may be implemented in accordance with an embodiment of the invention. FIG. 2 is a block diagram illustrating an exemplary set-top box board layout that may be used to implement the present invention. FIG. 3A is an exemplary screen shot that may be presented to a user upon start-up. FIG. 3B is an exemplary screen shot illustrating the selection of karaoke songs and/or movies to be transmitted in accordance with the present invention. FIG. 4 is an exemplary layout of a remote control that may be used to implement the present invention. FIG. 5 is a process flow diagram illustrating a method of playing a movie or karaoke selection in accordance with an embodiment of the invention. FIG. 6 is a process flow diagram illustrating a method of processing a user's voice input in accordance with an embodiment of the invention. FIG. 7 is a process flow diagram illustrating a method of pausing a movie or karaoke selection in accordance with an embodiment of the invention. FIG. 8 is a process flow diagram illustrating one method of stepping transmission of data in accordance with an embodiment of the invention. FIG. 9 is a process flow diagram illustrating one method of reducing the speed of data transmission to the set-top box in accordance with one embodiment of the invention. FIG. 10 is a process flow diagram illustrating a method of initiating or resuming the transmission of data in accordance with one embodiment of the invention. FIG. 11 is a process flow diagram illustrating a method of selecting data files to be transmitted via a menu in accordance with one embodiment of the invention. FIG. 12 is a process flow diagram illustrating one method of initiating the transmission of data associated with a next selected video in accordance with one embodiment of the invention. FIG. 13 is a process flow diagram illustrating a method of performing a seek in accordance with an embodiment of the invention. FIG. 14 is a process flow diagram illustrating one method of processing data received by the set-top box in accordance with one embodiment of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art, that the present invention may be practiced without some or all of these specific details. In other instances, well known process steps have not been described in detail in order not to unnecessarily obscure the present invention. With the recent advancement of digital technology, the way information flows and data are exchanged have taken a new direction. With the aid of video compression and decompression technology, digitized audio and video data can now be transmitted live across cities, states, and countries. Moreover, network bandwidth continues to increase through the introduction of fast Ethernet, cable modem, Digital Subscriber Line (DSL), variations of DSL (xDSL), and Gigabit Ethernet. DSL service enables the transmission of data at rates up to 6.1 megabits (millions of bits) per second, enabling continuous transmission of motion video, audio, and even 3-D effects. Accordingly, real-time video transmission which requires high bandwidth is now feasible. Through the use of the present invention, files such as movies and karaoke videos may be downloaded to a local server and streamed to one or more client devices (e.g., set-top boxes). In addition, interactive control of the streamed data is made available through the set-top boxes. Accordingly, the present invention provides the traditional advantages of a conventional video recorder without the restrictions or limitations of a video recorder. FIG. 1 is a block diagram illustrating an exemplary system in which the present invention may be implemented in accordance with an embodiment of the invention. The present invention is implemented in a network such as a local area network (LAN), which may be further coupled to a wide area network (WAN) such as the Internet. Within the network, one or more local servers 102 are used as the video-streaming server. Moreover, the local server(s) 102 may also be used as the content storage server that is capable of storing a plurality of files. One or more associated file servers 104 are used for user account management, content management, billing information, web server, firewall, and all other non-streaming related services. In addition, an equivalent central file server may be established at the central site which monitors and communicates with all the remote file servers. In order to decrease the costs associated with the local server 102 and limit the number of files available for transmission to each client, it may be preferable to use a suitable memory for storing approximately twenty files (e.g., karaoke files or movie files). However, this configuration is merely exemplary and a memory with a greater capacity may be implemented. These files may be supplied initially as well as downloaded from another server on the network, as well as from the Internet. The local server 102 is adapted for being coupled (e.g., via an Ethernet switch 106 ) to a plurality of devices 108 (e.g., set-top boxes) that are each configured to transmit a control command to the local server 102 to control the initiation and flow of data associated with a particular file to the requesting device 108 . In addition, each of the devices 108 is capable of providing video and audio signals to associated monitors or televisions 110 when they are received from the local server 102 . Through each device 108 , a client may initiate the transmission of data associated with a specified file via the local server 102 . In addition, once transmission of data is initiated, it may be desirable to interactively control the transmission of data from the local server 102 . When the requested file is not available to the local server 102 , the local server may access a central server 112 over the Internet via an Internet Service Provider (ISP) 114 . The central server 112 preferably has a vast data store of files in an associated memory. Alternatively, the client may independently download a requested file from the central server 112 via a web browser independently of transmission of the associated data to the client. For instance, when the user wants to watch a video that is not available on the local server, the user may access the central server and select one of a plurality of listed videos by clicking on the desired title(s). The central server 112 may then send the file to the local server 102 for storage in the file server 104 and/or transmission to a requesting client. It is important to note that each client device 108 and the local server 102 preferably perform authentication prior to establishing a communication link. When a file is transmitted from the central server 112 to a client via the local server 102 , the transmission and interactive control of the transmitted data may be performed in a manner to enable real-time streaming and therefore instantaneous access to the data by a requesting client. Alternatively, there may be a small or considerable delay, depending upon the transmission medium that is used. For instance, the transmission medium used to transmit data from the central server 112 to the local server 102 , and from the local server 102 to each device 108 may include a traditional transmission medium such as a cable modem connection. In a WAN setting, bandwidth cannot be guaranteed at a sustainable rate to support real-time broad-band video streaming. Thus, it is important to note that the benefit of a the local server 102 in a LAN setting is to provide sustainable bandwidth to guarantee uninterrupted real-time video streaming. Traditional phone service transmits an analog signal which is converted into digital information by a modem. However, the maximum amount of data that may be received using an ordinary modem is currently approximately 56 Kbps. In contrast, with various xDSL technologies, it is possible to receive data at rates of well over one million bits per second (Mbps), enabling continuous transmission of motion video, audio, and 3-D effects. For example, current ADSL standards contemplate data receive rates on the order of 6 Mbps. VDSL proposals contemplate data receive rates on the order of 25 or 50 Mbps. Thus, the delay involved in transmission of the requested data may be minimized through the use of a Digital Subscriber Line (DSL) or variations of DSL (xDSL). As a result, video quality is improved. Moreover, since multiple devices 108 may be coupled to the central server 112 through a single Digital Subscriber Line via the local server 102 , each client need not individually obtain DSL service. In this manner, the cost to the consumer is considerably reduced while enabling the consumer to interactively control data transmission via the central server 112 with approximately instantaneous access. The present invention may be used by a business such as a hotel to enable multiple rooms to access a local server maintained by the hotel. Since the local server is maintained by the hotel, the hotel may wish to bill a guest each time a movie or karaoke song is played (i.e., transmitted from the local server 102 to a client device 108 ). Moreover, the hotel may wish to bill the guest an additional amount when the requested selection is transmitted from the central server over the Internet to the guest's hotel room (e.g., when the user accesses the central server via a web browser). Of course, it may be desirable to bill a guest once (e.g., when the associated file is loaded from the central server to the local server) while allowing the guest to view the selection multiple times. Billing information may be obtained in a variety of ways. For instance, billing information associated with the hotel room may be automatically obtained. As another example, billing information such as credit card information may be obtained from the user upon selection of a video. As yet another example, a smart card reader may be provided to enable the user to charge room services to his or her smart card. As described above with reference to FIG. 1 , multiple client devices 108 may be coupled to a single local server 102 . In accordance with one embodiment of the invention, a client device 108 may be implemented in the form of a set-top box. A set-top box is a device that enables a television set to become a user interface to the Internet and also enables a television set to receive and decode digital television broadcasts. More particularly, a set-top box is used by television viewers to receive digital broadcasts via an analog television set. A set-top box typically includes a Web browser stored in a memory in the set-top box, enabling a television user to access the Internet. In addition, a typical digital set-top box contains one or more microprocessors for running the operating system and for parsing an MPEG transport stream. A set-top box also includes RAM, an MPEG decoder chip as well as other chips for audio decoding and processing. In addition, a set-top box may contain a hard drive for storing recorded television broadcasts, for downloaded software, and for other applications. Similarly, a DVD drive may be used to enable the set-top box to access a variety of files. FIG. 2 is a block diagram illustrating an exemplary set-top box board layout that may be used to implement the present invention. In one embodiment, the set-top box board implements a standard Ethernet implementation and therefore includes a 10BaseT Interface 202 , an Ethernet controller 204 , an EEPROM 206 for storing an IP address associated with the set-top box board, and SRAMs 208 , 210 for storing data obtained from the network (e.g., Internet). In addition, the set-top box includes a CPU 212 for running the operating system and for parsing an MPEG data stream. In addition, a flash EPROM 214 may store software for drivers and other instructions necessary to implement the present invention. Moreover, this client software that is programmed into the flash EPROM 214 may be updated through the local server at any time for feature enhancement. System memory 216 (e.g., DRAM) is available for use by the CPU. In addition, EPLD 218 is adapted for routing signals among components, thereby providing the appropriate combinational logic for the set-top box. MPEG decoder 220 is provided for decompressing video and audio data received in the compressed data received by the set-top box. DRAM chips 222 , 224 , 226 , 228 , and 230 are provided for storing video data for the MPEG decoder 220 . After the video and audio data is decompressed by the MPEG decoder 220 , the decompressed audio and video signals are processed separately. The decompressed video signal is then sent from the MPEG decoder 220 to a video encoder 242 to convert the digital video signal to an analog signal. The analog video signal is then output at a video input/output 244 . The decompressed audio signal is sent from the MPEG decoder 220 to digital-to-analog converter 236 and output via stereo output 238 and therefore through an amplifier (not shown). In accordance with one embodiment, the set-top box includes karaoke capabilities. Thus, in addition to the data (e.g., karaoke file) received from the network, one or more microphone inputs 231 and 232 are provided to enable users to sing along with a karaoke selection. In the embodiment shown, two microphone inputs are supported, although it should be appreciated that any desired number of microphones may be provided. When a karaoke singer sings into a microphone, the audio signal is processed by an analog to digital converter 233 . The digital audio signal is then sent to a karaoke audio processor 234 . For instance, the karaoke audio processor 234 may be a digital karaoke audio processor such as model MED25102 available from Medianix Semiconductor, Inc., located at 100 View Street, Mountain View, Calif. 94041. The digital audio signal processed by the karaoke processor 234 is then sent to digital-to-analog converter 236 and output via stereo output 238 . In addition, a DRAM chip 240 is available for storing audio data for the karaoke processor 234 . A standard audio input 246 is also provided. In addition, an infra-red interface controller (not shown) may be provided to enable communication with a remote control device. In accordance with one embodiment, the set-top box is capable of switching between NTSC and PAL signals for world-wide adoption and compatibility. In addition, to implement a karaoke system, user interfaces in different languages may be provided by the set-top box. Similarly, files encoded with sound tracks in multiple languages may be provided at the local server to enable a sound track in a particular language to be selected at the set-top box. FIG. 3A is an exemplary screen shot that may be presented to a user upon start-up. As shown, an initial screen 302 may be displayed which indicates one or more selections which may be input by a user. For instance, at start-up, a default selection type 304 may be presented to the user. More particularly, the selection type 304 of a file to be transmitted may be, for example, “karaoke” or “movie”. Thus, the default selection type 304 may be “karaoke”, as shown. In addition, the user may indicate a particular selection 306 associated with the selection type 304 . As shown, a number, title, or other mechanism may be used to identify each selection. FIG. 3B is an exemplary screen shot illustrating the selection of karaoke songs and/or movies to be transmitted in accordance with the present invention. Once the user has entered one or more selections, a TV screen or monitor 308 after all selections are entered is displayed. Thus, the selection type 310 may be “movie” or “karaoke”, as shown. In addition, each selection 312 is identified numerically in accordance with a pre-selected set of selections available to the user. For instance, a manual may be provided to the user identifying the selections available to the user. As described above, the user sends control commands to the set-top box indicating desired modifications to the flow of data to the set-top box. In accordance with one embodiment, these control commands are sent to the set-top box via an infra-red remote control. FIG. 4 is an exemplary layout of a remote control that may be used to implement the present invention. A TV/VIDEO key 402 enables a user to toggle between a television and video mode. In addition, a NEXT key 404 stops the current video (e.g., movie or karaoke) and starts the next video selected. An ENTER key 406 enables a user to enter a number of key strokes. In addition, an NTSC/PAL key 408 enables a user to switch between NTSC and PAL mode, as described above. A RESET key 410 reboots the set-top box. A VIEW/MENU key 412 enables a user to view a video after all karaoke or movie selections are entered. During video play, when the VIEW/MENU key 412 is toggled, a menu screen is displayed to enable the user to add or edit the video selections. The user may then toggle the VIEW/MENU key 412 an additional time to start playing the current video selection. Number keys 0 – 9 413 – 430 may be used to identify video titles. Arrow keys 432 – 438 move the cursor up, down, right or left to enable a user to enter or modify selections. Various control keys are provided to initiate or modify the flow of data to the set-top box. When a PLAY key 440 is pressed, a selected video (e.g., movie or karaoke selection) is played at normal speed from either a PAUSE, STEP, or SLOW mode, each of which will be described in further detail below. In addition, in accordance with one embodiment, a percent video played indicator is displayed on the screen to indicate the amount of the video that remains to be transmitted. When a SLOW key 442 is pressed, the video speed is slowed (e.g., to one-half normal speed). The PLAY key 440 may then be pressed to resume to normal speed. Similarly, when a PAUSE key 444 is pressed, the video is paused until the PLAY key 440 , the SLOW key 442 , or a STEP key 446 is pressed. Once the STEP key 446 is pressed, the video is advanced by one frame at a time. Rather than viewing the entire video, the user may wish to view only specific portions of the video. When a SEEK key 448 is pressed during video play, the user may select a percentage of the video file to jump to. The video then jumps to that location and begins to play starting from that location. The seek location may be any location in the video file. Accordingly, the seek function may operate in forward or reverse. In addition to video control keys described above, karaoke control keys are provided to enable the user to modify the audio signal associated with the karaoke music and/or the user's voice. The key functions may be implemented through the use of a conventional karaoke audio processor such as karaoke audio processor MED25102 available from Medianix. Various keys are provided on the remote control to implement various functions available in a karaoke processor. For instance, KEY− 450 decreases the key of the music, KEY+ 452 increases the key of the music, KEY N 454 returns the key of the music to neutral, VOL+ 456 increases the microphone volume, VOL− 458 decreases the microphone volume, ECHO+ 460 increases microphone echo, and ECHO− 462 decreases microphone echo. When FADER 464 key is pressed, the vocal portion of the music is silenced. PITCH 466 changes the pitch of the karaoke singer's voice that is received through the microphone by shifting the pitch one semi-note with each depression. HARMONY 468 adds a pitch-shifted and a non pitch-shifted microphone signal to create the sound of two vocalists. MUTE 470 mutes the associated microphone. As described above with reference to FIG. 4 , a remote control may enable a user to modify the flow of data to a set-top box. However, other input devices may be used. For instance, such input devices include, but are not limited to, a keyboard or a mouse. Through the use of the present invention, data may be transmitted from a particular network device to a requesting network device. In accordance with one embodiment, data is transmitted to a set-top box from a local server. Of course, when a particular file is not directly accessible by the local server, the file may be downloaded from a central server (e.g., to a file server associated with the local server). In addition, data may be transmitted from the central server via the local server. The downloading and/or transmission from the central server to the local server may be initiated by the user (e.g., via a web browser) or by the local server when the file cannot be directly accessed by the local server. Once data flow associated with a file is initiated, the data flow may be modified through the sending of various control commands by the user (e.g., via an infra-red remote control). In accordance with one embodiment, data flow from the local server may be modified by the user. The flow of data and modification of the data flow from the local server will be described in further detail below with reference to FIG. 5 through FIG. 14 . However, it will be understood that the flow of data and modification of the data flow may also be performed via the central server. FIG. 5 is a process flow diagram illustrating a method of playing a movie or karaoke selection in accordance with an embodiment of the invention. When the set-top box is turned on at block 502 , a menu is displayed at block 504 . For instance, a screen such as that illustrated in FIG. 3A may be displayed to enable a user to enter one or more karaoke or movie selections as shown in FIG. 3B . The user enters one or more selections at block 506 to indicate those movies, karaoke selections or other video files to be transmitted to the set-top box. The user then selects a control command at block 508 to initiate, terminate or otherwise modify the flow of data to the set-top box. Thus, the control command generally indicates a desired modification of the flow of data to the set-top box. More particularly, this may be accomplished by pressing a key on a remote control such as that described above with reference to FIG. 4 . For instance, the user may select the VIEW command in order to view a selected video. When the control command (e.g., view command) is received by the set-top box at block 510 , the set-top box deciphers the infra red control signal and sends the control command to a CPU of the set-top box at block 512 . The set-top box then sends the control command to the local server at block 514 . The local server receives the control command at block 516 . In addition, the local server may receive a signal indicating a current video selection. The local server then sends a compressed data stream over a network to the set-top box at block 518 . More particularly, the compressed data stream may include audio, video and other digital data. The set-top box then processes the data received from the local server at block 520 . One method of processing the data by the set-top box is described in further detail below with reference to FIG. 14 . In accordance with one embodiment, the user may initiate and modify the transmission of karaoke data from a server to the set-top box. Thus, a first audio signal is received by the set-top box from a server and processed, as will be described below with reference to FIG. 14 . In addition, the user may sing along with the karaoke selection through a microphone, creating a second audio signal. FIG. 6 is a process flow diagram illustrating a method of processing a user's voice input in accordance with an embodiment of the invention. More particularly, when a user sings through a microphone connected to the set-top box at block 600 , the audio signal is processed by an analog to digital converter at block 602 . In addition, the user may select an audio control command as shown at block 604 via a karaoke control key as described above with reference to FIG. 4 to modify the audio signal that is ultimately produced by the set-top box. For instance, the user may wish to adjust the volume or pitch. The singer's voice is then processed by the karaoke processor at block 606 to modify the second audio signal. This modified second audio signal is then sent to a digital to analog converter at block 608 . The resulting analog audio signal is then sent to an amplifier at block 610 . The flow of data to the set-top box may be modified in a variety of ways. As described above with reference to FIG. 4 , the flow of data may be modified in a variety of ways. For instance, the user may wish to pause a video, or press a remote control key such as STEP, SLOW, PLAY, MENU, NEXT, or SEEK. Exemplary process flow diagrams illustrating such possible modifications to the flow of data to a set-top box will be described in further detail below with reference to FIG. 7 through FIG. 13 . When a user wishes to pause the transmission of data to the set-top box, the user may press the PAUSE button on the remote control. FIG. 7 is a process flow diagram illustrating a method of pausing a movie or karaoke selection in accordance with an embodiment of the invention. As shown, when a user selects a pause control command at block 702 , the set-top box deciphers the infra-red control at block 704 . The pause control command is then sent to a CPU of the set-top box at block 706 . The set-top box sends the pause control command to the local server at block 708 . In response, as shown at block 710 , the local server stops sending data to the set-top box until further instruction. A user may press the STEP key when he or she wishes to step the transmission of data (e.g., by a single frame). FIG. 8 is a process flow diagram illustrating one method of stepping transmission of data in accordance with an embodiment of the invention. As shown at block 802 , a user may select the step control command through pressing the STEP key on a remote control. When the infra red signal is received by the set-top box, the set-top box deciphers the infra red signal at block 804 and sends a step control command to a CPU of the set-top box at block 806 . The set-top box (e.g., CPU) then transmits this step control command to the local server at block 808 . In response, the local server advances the appropriate video by a frame by sending data associated with that frame to the set-top box at block 810 . The set-top box then processes the data received from the local server at block 812 , as will be described in further detail below with reference to FIG. 14 . A user may similarly wish to modify the speed of transmission of data to the set-top box over the network. For instance, the user may wish to reduce as well as increase the speed of data transmission. FIG. 9 is a process flow diagram illustrating one method of reducing the speed of data transmission to the set-top box in accordance with one embodiment of the invention. When a user wishes to slow the speed of data transmission, the user may press a SLOW key on a remote control as shown at block 902 , as described above with reference to FIG. 4 . The set-top box deciphers the infra red control at block 904 and a slow control command indicating that the data transmission is to be slowed is sent to a CPU of the set-top box at block 906 . The set-top box then sends the slow control command to the local server at block 908 . In response to the control command, the local server reduces the speed with which data (e.g., frames) are sent to the set-top box at block 910 . The local server then continues to send compressed data over the network to the set-top box at block 912 . The set-top box then processes the data received from the local server at block 914 , which will be described in further detail below with reference to FIG. 14 . The user may also wish to initiate the transmission of data over the network to the set-top box (e.g., from a pause mode). Alternatively, the user may wish to resume transmission of data to a normal speed from a step or slow mode. FIG. 10 is a process flow diagram illustrating a method of initiating or resuming the transmission of data in accordance with one embodiment of the invention. As shown at block 1002 , the user may select the play control command at block 1002 . This may be accomplished through pressing the PLAY key on a remote control such as that illustrated in FIG. 4 . For instance, the PLAY key may be pressed from the pause, step, or slow mode. The set-top box then deciphers the infra red control at block 1004 and a play control command indicating that initiation of the transmission of data is requested is sent to a CPU of the set-top box at block 1006 . The set-top box then sends the play control command to the local server at block 1008 . The local server then initiates the transmission of data at block 1010 . More particularly, the local server may initiate the transmission of data or simply return to normal speed with which data is sent to the set-top box. The local server continues to send compressed data over the network to the set-top box at block 1012 . In addition, in accordance with one embodiment, the local server sends a percentage value indicating a percent of the file that has been transmitted (e.g., percent of a movie that has been played over the network). The set-top box processes the data it receives from the local server at block 1014 , as will be described in further detail below with reference to FIG. 14 . The set-top box further displays the percent of the selection that has been transmitted to the set-top box and therefore played for the user at block 1016 . As described above, the data may be associated with any file, such as a movie or karaoke selection. The user may wish to edit his or her selections that have been previously entered via a screen such as that illustrated in FIG. 3A and FIG. 3B . In this manner, the user may specify via the set-top box an order of transmission of one or more files. The files may be of varying types, such as those storing movies or karaoke videos. It is important to note that the files being selected are not stored locally at the set-top box, but identify files stored in association with a remotely located server on the network. FIG. 11 is a process flow diagram illustrating a method of selecting data files to be transmitted via a menu in accordance with one embodiment of the invention. As shown, the user may select a menu control command at block 1102 which sends an infra red signal to the set-top box. The set-top box deciphers the infra red control at block 1104 and sends this menu control command to a CPU of the set-top box at block 1106 . The set-top box sends this menu control command over the network to the local server at block 1108 . The local server then stops sending compressed data over the network to the set-top box at block 1110 . For instance, the local server may stop sending data until a VIEW/MENU key on a remote control such as that illustrated in FIG. 4 is toggled by the user. The set-top box then displays a menu of selections at block 1112 . As one example, the menu may present the user with a number of possible files (e.g., movie or karaoke) to be transmitted to the set-top box. As another example, the menu may simply be a screen such as that presented in FIG. 3A which may enable a user to enter as well as modify his or her selections as illustrated in FIG. 3B . When presented with this menu, the user may add as well as edit the menu selections that are displayed at block 1114 . As one example, the user may have be presented with a screen illustrating a single previously entered selection. The user may then enter or select additional selections up to a maximum number of permissible selections. As another example, the menu may present the user with a number of selections previously selected by the user. The user may then modify one or more of these selections. When the user decides to view one or more of his selections, the view control command may be selected by again toggling the VIEW/MENU key at block 1116 . The set-top box deciphers the infra-red control at block 1118 and a view control command is sent to a CPU of the set-top box at block 1120 . The set-top box sends the view control command over the network to the local server at block 1122 . For instance, the view control command may identify one or more files to be transmitted over the network. In addition, the view control command may also indicate the order of transmission of those files. Of course, the view control command may also designate a starting point from which compressed data is to be transmitted. The starting point may indicate a specific file as well as a location (e.g., percentage) within that file. The local server then resumes sending compressed data over the network to the set-top box at block 1124 . The set-top box then processes the data it receives at block 1126 , which will be described in further detail below with reference to FIG. 14 . Rather than allowing all selections to play consecutively, the user may wish to terminate a current video and start the next selected video. FIG. 12 is a process flow diagram illustrating one method of initiating the transmission of data associated with a next selected video in accordance with one embodiment of the invention. When the user wishes to stop the transmission of data associated with a first video and start the transmission of data associated with a second video, the user may select the next control command at block 1202 by pressing the NEXT key on a remote control such as that illustrated in FIG. 4 . The set-top box deciphers the infra red control at block 1204 . A next control command indicating that a next video is selected is then sent to a CPU of the set-top box at block 1206 . The set-top box sends the next control command to the local server indicating that the next video is selected as shown at block 1208 . For instance, the next control command may directly or indirectly identify a currently selected video. At block 1210 the local server stops sending compressed data associated with the previous selection over the network to the set-top box. The local server then sends compressed data associated with the current selection over the network to the set-top box at block 1212 . The set-top box then processes the data it receives from the local server at block 1214 . One method of processing the compressed data will be described in further detail below with reference to FIG. 14 . When a user wishes to initiate transmission of data from a particular location in a file, the user may press the SEEK key of a remote control such as that illustrated in FIG. 4 . FIG. 13 is a process flow diagram illustrating a method of performing a seek in accordance with an embodiment of the invention. As shown at block 1302 the user may select the seek control command by pressing the SEEK key of a remote control at block 1302 . In addition, the user indicates a location in the video file from which data transmission is desired at block 1304 . In accordance with one embodiment, the user selects a percentage of a video file that has been transmitted. The set-top box deciphers the infra red control at block 1306 and the corresponding seek control command indicating the desired percentage is sent to a CPU of the set-top box at block 1308 . In accordance with one embodiment, the starting point in the file from which data is to be transmitted is calculated by the set-top box. More particularly, when the file is initially selected, the local server sends information associated with the file such as the size of the file to the set-top box. For instance, when an MPEG file is transmitted, file information is transmitted in the initial packets that are transmitted. The set-top box uses the size of the file and the percentage to determine a starting point in the file at block 1310 . The set-top box then sends an indicator of the desired file location to the local server at block 1312 . Alternatively, the calculation of the starting point may be performed by the local server. In accordance with this embodiment, the set-top box sends the seek control command indicating the desired percentage over the network to the local server at block 1310 . When the local server receives the seek control command, the local server uses the size of the file and the percentage to determine a starting point in the file at block 1312 . The local server then “jumps” to this starting point in the file at block 1314 and initiates the transmission of compressed data from the starting point over the network to the set-top box at block 1316 . The set-top box then processes the data it receives from the local server at block 1318 , which will be described in further detail below with reference to FIG. 14 . As described above, when the set-top box receives compressed data sent over the network, the set-top box processes this data. FIG. 14 is a process flow diagram illustrating one method of processing data received by the set-top box in accordance with one embodiment of the invention. A variety of commands sent by the set-top box result in compressed video data being sent to a requesting client (e.g., set-top box). When the client sends a request to a server asking the server to send compressed video data to the client, the server splits the associated compressed video data file (or portion thereof) into multiple packets and sends the packets to the client. As shown at block 1402 the set-top box receives the compressed video data from the local server. An MPEG decoder chip then decompresses video and audio data in the compressed data at block 1404 . The decompressed video signal is then sent to a video encoder to convert the digital signal to an analog signal at block 1406 . The resulting analog signal is then output to a television or monitor at block 1408 . The data received by the set-top box may be stored for future use. However, it may be desirable to delete the data once it is provided by the set-top box to the user. In this manner, a video may be displayed in real-time onto a television screen. In addition to the decompressed video data, the decompressed audio data is also processed by the set-top box. More particularly, in accordance with the karaoke embodiment, the decompressed audio signal is sent to the karaoke processor at block 1410 . The processed audio signal is then sent to a digital to analog converter at block 1412 . The resulting analog audio signal is then sent to an amplifier at block 1414 . When data is transmitted from the central server to the set-top box via a local server, the local server may store a copy of this data (e.g., in an associated file server). Alternatively, it may be desirable to erase this copy once the data is transmitted to a requesting set-top box. The present invention may be used in a variety of environments. For instance, the above-described system may be configured as a networked karaoke system to enable a plurality of rooms to access karaoke songs concurrently without the intervention of a human operator. The present invention may also be used to provide hotels a cost-effective solution to deliver movies to hotel guests. Moreover, it may also be useful in hospitals to enable bed-ridden patients to watch movies or surf the Internet. Schools may also implement the present invention within a campus local area network to transmit video-taped lectures or other presentations. Additionally, long trips in a confined seat takes a toll on passengers in a common carrier such as an airplane, cruise ship, train or bus. Thus, the present invention may allow each passenger to watch and control a movie he or she is interested in throughout the entire trip. It may also be desirable to implement the present invention within an apartment complex to enable the system as well as system costs to be shared by each residential unit. Additionally, the present invention may be deployed as a video kiosk in airports, train stations, hotel lobbies, department stores, conventions, or museums for information, catalog or advertisement purposes. The emergence of the Internet has created a world-wide data network. As Internet traffic grows steadily, the data highway's bandwidth increases accordingly. This presents a major opportunity for a new class of dedicated communication devices that will allow users to conduct communication (e.g., via voice and video data) through the data network. This information exchange has evolved from text-based to graphics-based to content-rich, video-based communications capable of providing a multitude of services. Accordingly, the present invention may be implemented in a device or web browser to provide interactive, real-time, high-bandwidth services to a user using the Internet. As described above, the present invention enables a client device such as a set-top box to receive data streams such as video streams that are transported over a network from a video server. In addition, the set-top box might output information to the network in the course of performing the above-described method steps. Such information may be received from and outputted to the network, for example, in the form of a computer data signal embodied in a carrier wave. The network may also be a wireless network. Through the use of the present invention, video, audio, and karaoke functionality are integrated in a single system capable of interfacing to a standard television. Since the present invention is implemented in a set-top box, it is compact and portable. Moreover, since a computer system is not required, the present invention may be manufactured at a relatively low cost to the consumer. Although illustrative embodiments and applications of this invention are shown and described herein, many variations and modifications are possible which remain within the concept, scope, and spirit of the invention, and these variations would become clear to those of ordinary skill in the art after perusal of this application. For instance, the present invention is described as transmitting data from a local server within the context of a digital television receiver. However, the present invention may be used in other contexts, such as through transmitting data from another server (e.g., central server) via the local server. For instance, the present invention may permit access to a central server on the Internet. Similarly, the present invention may be implemented across a plurality of staged servers, enabling information to be transmitted across the Internet. Moreover, the above described process blocks are illustrative only. Therefore, the present invention may be performed using alternate process blocks as well as alternate data structures. Accordingly, the present embodiments are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope and equivalents of the appended claims.

Methods and apparatus for use in a network including a local server coupled to a central server, the local server being coupled to a plurality of network devices, for interactively controlling from one of the plurality of network devices a flow of audio visual data from the central server to the network device, comprising obtaining a control command at the network device, the control command indicating a desired modification to the flow of the audio visual data from the central server to the network device. The control command is sent from the network device to the central server via the local server. A modified flow of the audio visual data is then received from the central server at the network device in response to the control command.

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a wavelength conversion device composed of a semiconductor laser device and a nonlinear optical element having a planar optical waveguide, which are mounted on a substrate in an integrated manner. [0003] 2. Related Background Art [0004] In order to realize a high-density optical disk and a high-definition display, small short-wavelength light sources generating a laser beam in a blue range through violet range are desired. Techniques for obtaining a laser beam in this wavelength range include a second harmonic-wave generation method (hereinafter referred to as “SHG”) that employs a wavelength conversion device using a planar optical waveguide according to a quasi-phase-matching method, by which a wavelength of a semiconductor laser can be converted from 850 nm into 425 nm. [0005] To miniaturize a short-wavelength light source according to this method, it is effective to mount a wavelength conversion device and a semiconductor laser device on a substrate in an integrated manner. [0006] [0006]FIG. 15 shows one example of these small short-wavelength light sources, which is a wavelength conversion device disclosed in JP 2000-284135 A. [0007] A semiconductor laser device 306 and a planar optical waveguide device 305 are mounted on a silicon substrate 300 in an integrated manner. The planar optical waveguide device 305 functions as a wavelength conversion device structured by forming a proton exchange planar optical waveguide 304 and a diffraction grating (not illustrated) with periodic domain inverted regions formed therein on an Mg doped LiNbO 3 substrate 302 . In addition, on the silicon substrate 300 , electrodes 307 electrically connected to the semiconductor laser device 306 are formed, and alignment keys 301 are formed at positions 10 μm away from the planar optical waveguide 304 . On each side of the planar optical waveguide 304 , alignment keys 303 are formed using a film made of the same material (e.g., Ta) and having the same thickness as those of the alignment keys 301 . Further, alignment keys 308 are formed on the semiconductor laser device 306 as well. [0008] Here, the semiconductor laser device 306 is a Distributed Bragg Reflector (hereinafter, referred to as “DBR”) type semiconductor laser device. As shown in FIG. 15, the electrodes 307 are connected to each of a gain region and a wavelength control region, i.e., a DBR region (not illustrated) of the semiconductor laser device 306 . [0009] The semiconductor laser device 306 and the planar optical waveguide device 305 are mounted onto the silicon substrate 300 in such a manner that a laser beam emitted from the semiconductor laser device 306 is guided through the optical waveguide 304 in the planar optical waveguide device 305 , and the alignment keys 308 , 303 , and 301 are arranged at their predetermined positions. In this wavelength conversion device, a center line M 1 -M 2 of the silicon substrate 300 , a center line M 5 -M 6 of the semiconductor laser device 306 , and a center line M 3 -M 4 of the planar optical waveguide device 305 approximately coincide with one another. [0010] In the future, to miniaturize an optical information processing system employing an optical disk and a display still more than present ones, an optical pick up unit included in an optical disk or the like needs to be made small. To this end, it becomes effective to make a wavelength conversion device smaller. [0011] Meanwhile, when electrically driving such a wavelength conversion device, an oscillation wavelength of a laser beam emitted from the semiconductor laser device 306 needs to be controlled so as to maximize a conversion efficiency of the laser beam by the SHG. [0012] In the wavelength conversion device shown in FIG. 15, by controlling a current applied to the electrode connected to the DBR region, among the electrodes 307 , a refractive index of the DBR region is varied so as to change a Bragg wavelength, whereby the oscillation wavelength is controlled. In this wavelength conversion device, however, a phase of the emitted laser beam cannot be controlled, because the semiconductor laser device 306 consists of only two regions, i.e., the gain region and the DBR region. Due to such a constraint, if a Bragg wavelength in the DBR region is varied by the passage of the electric current, then a so-called mode hoping would occur, where the oscillation wavelength changes discontinuously. In this case, it becomes difficult to control the oscillation wavelength, which might interfere with the operation of the device significantly. SUMMARY OF THE INVENTION [0013] Therefore, with the foregoing in mind, it is an object of the present invention to provide a small short-wavelength conversion device composed of a semiconductor laser device and an optical waveguide device, which are mounted on a substrate in an integrated manner. [0014] To fulfill the above-stated object, a wavelength conversion device according to an embodiment of the present invention, which converts a wavelength by second harmonic-wave generation and generates a laser beam, includes: a substrate having a plurality of electrodes; a semiconductor laser device mounted on the substrate and electrically connected to the plurality of electrodes; and a nonlinear optical element having an optical waveguide for guiding a laser beam emitted from the semiconductor laser device and for converting a wavelength of the laser beam. Here, the nonlinear optical element is mounted on the substrate in such a manner that the optical waveguide in the nonlinear optical element is located away from the center line of the substrate. [0015] To fulfill the above-stated object, a wavelength conversion device according to another embodiment of the present invention, which converts a wavelength by second harmonic-wave generation and generates a laser beam, includes: a substrate having a plurality of electrodes; a semiconductor laser device electrically connected to the plurality of electrodes; and a nonlinear optical element having an optical waveguide for guiding a laser beam emitted from the semiconductor laser device and for converting a wavelength of the laser beam. Here, the semiconductor laser device, the optical waveguide of the nonlinear optical element, and the plurality of electrodes are on approximately one line on the substrate. [0016] It is another object of the present invention to provide a wavelength conversion device by which an oscillation wavelength of a laser beam emitted from a semiconductor laser device can be controlled with stability. [0017] To fulfill the above-stated object, a wavelength conversion device according to an embodiment of the present invention, which converts a wavelength by second harmonic-wave generation and generates a laser beam, includes: a substrate having a plurality of electrodes; a semiconductor laser device mounted on the substrate and including three regions of a gain region, a phase control region, and a wavelength control region; and a nonlinear optical element mounted on the substrate and for converting a wavelength of a laser beam emitted from the semiconductor laser device. Here, the plurality of electrodes include a first electrode group formed corresponding to the three regions and a second electrode group for carrying out wire-bonding with an external power source, the three regions of the semiconductor laser device are connected electrically to the respective electrodes in the first electrode group, and the first electrode group further is connected to the respective electrodes in the second electrode group via wires, and a wire among the wires, which is connected between the phase control region and the wavelength control region of the semiconductor laser device, has a portion functioning as a resistor. BRIEF DESCRIPTION OF THE DRAWINGS [0018] [0018]FIG. 1 is a plan view of a wavelength conversion device according to Embodiment 1; [0019] [0019]FIG. 2 is a plan view of a wavelength conversion device according to Embodiment 2; [0020] [0020]FIG. 3 is a plan view of a wavelength conversion device according to Embodiment 3; [0021] [0021]FIG. 4 is a plan view of a wavelength conversion device according to Embodiment 4; [0022] [0022]FIG. 5 is a plan view of a wavelength conversion device according to Embodiment 5; [0023] [0023]FIG. 6 is a plan view of a wavelength conversion device according to Embodiment 6; [0024] [0024]FIG. 7 is a plan view of a wavelength conversion device according to Embodiment 7; [0025] [0025]FIG. 8 is a plan view of a wavelength conversion device according to Embodiment 8; [0026] [0026]FIG. 9 is a plan view of a wavelength conversion device according to Embodiment 9; [0027] [0027]FIG. 10 is a plan view of a wavelength conversion device according to Embodiment 10; [0028] [0028]FIG. 11 is a plan view of a wavelength conversion device according to Embodiment 11; [0029] [0029]FIG. 12 is a plan view of a wavelength conversion device according to Embodiment 12; [0030] [0030]FIG. 13 is a graph showing the relationship among oscillation longitudinal mode orders, and amount of current fed into a phase control region and a DBR region; [0031] [0031]FIG. 14 is a circuit diagram showing a state where the phase control region and the DBR region of the semiconductor laser device are driven at the same voltage; and [0032] [0032]FIG. 15 is a plan view of a wavelength conversion device according to the prior art. DETAILED DESCRIPTION OF THE INVENTION [0033] The following describes embodiments of the present invention, with reference to the drawings. [0034] [Embodiment 1] [0035] [0035]FIG. 1 is a plan view of a wavelength conversion device according to this embodiment. On a silicon substrate (3 mm in width, 15 mm in length), electrodes 1 , 2 , and 3 are formed by patterning, and a DBR laser element 4 (0.3 mm in width, 1.2 mm in length) and a nonlinear optical element 7 (2.8 mm in width, 10 mm in length) are mounted in an integrated manner. Numeral 6 denotes an optical waveguide, and 8 denotes a diffraction grating formed in the optical waveguide 6 . Line 100 is a center line of the optical waveguide 6 . Line M 1 a -M 2 a is a center line of the width direction of the silicon substrate 5 , and line M 5 a -M 6 a is a center line of the width direction of the nonlinear optical element 7 . Hereinafter, in the wavelength conversion devices according to the present invention, the direction perpendicular to the optical waveguide is referred to as the width direction, while the direction parallel to the optical waveguide is referred to as the longitudinal direction. [0036] The DBR laser element 4 is made up of three regions including a gain region that adjusts an output power of a laser beam emitted therefrom, a phase control region that changes a phase of the laser beam, and a DBR region that feeds back a laser beam with an oscillation wavelength into a cavity. Note here that these regions referred to in this embodiment or later in this specification have the functions as stated above. [0037] With respect to these three regions, electrodes that are electrically isolated from one another are formed (not illustrated). The DBR laser element 4 is mounted on the silicon substrate 5 in a junction down manner where a surface with the p-n junction faces to the side of the silicon substrate 5 , and electrodes corresponding to the gain region, the phase control region, and the DBR region are bonded to the electrodes 1 , 2 , and 3 on the silicon substrate 5 , respectively. Also, wire-bonding regions are formed in each of the electrodes for carrying out wiring with an external power source so as to electrically drive the gain region, the phase control region, and the DBR region. [0038] In this way, the gain region, the phase control region, and the DBR region of the DBR laser element 4 are connected electrically to the electrodes 1 , 2 , and 3 , respectively. In this state, by feeding an electrical signal to each of the electrodes, an oscillation wavelength of the laser beam emitted from the DBR laser element 4 can be varied. The oscillation wavelength of the laser beam emitted from the DBR laser element 4 is set at 820 nm, and the beam is oscillated in the single longitudinal mode. [0039] The nonlinear optical element 7 is made of LiNbO 3 , and the optical waveguide 6 having the diffraction grating 8 is formed therein. The nonlinear optical element 7 is fixed onto the silicon substrate 5 at a predetermined position with an adhesive such as a UV curing agent. [0040] The diffraction grating 8 is formed by inverting a polarization of LiNbO 3 crystals with the application of an external electric field. The optical waveguide 6 is positioned within 3 μm of the DBR laser element 4 so as to introduce the laser beam emitted from the DBR laser element 4 securely. [0041] When guiding the laser beam through the optical waveguide 6 , a second harmonic-wave generated beam (hereinafter, referred to as “SHG beam”) with a wavelength of 410 nm generated in the nonlinear optical element 7 due to a diffraction by the diffraction grating 8 and the laser beam with an oscillation wavelength of 820 nm are quasi-phase matched. Thereby, an SHG beam having a high output power can be obtained. In addition, by controlling the oscillation wavelength of the laser beam emitted from the DBR laser element 4 , a conversion efficiency into the SHG beam can be improved. [0042] In this embodiment, as shown in FIG. 1, the nonlinear optical element 7 is mounted on the silicon substrate 5 in such a manner that the center line 100 of its optical waveguide 6 is 1.0 mm away from the center line M 1 a -M 2 a of the silicon substrate 5 . In this way, in this embodiment, the optical waveguide 6 does not necessarily need to be formed on the center line M 5 a -M 6 a of the nonlinear optical element 7 . [0043] In addition, the nonlinear optical element 7 is mounted so that the center line M 1 a -M 2 a of the silicon substrate 5 coincides with the center line M 5 a -M 6 a of the nonlinear optical element 7 in FIG. 1. However, these center lines do not necessarily coincide with each other. [0044] Furthermore, the end of the optical waveguide 6 at the side of the nonlinear optical element 7 where the SHG beam is emitted is located at least 5 μm beyond the edge of the silicon substrate 5 . This construction prevents the SHG beam from being reflected from the silicon substrate 5 and scattered, and therefore a favorable image can be obtained in the far field for the SHG beam emitted from the nonlinear optical element 7 . [0045] According to this embodiment, since the nonlinear optical element 7 is mounted on the substrate in such a manner that its optical waveguide 6 is located away from the center line M 1 a -M 2 a of the silicon substrate 5 , the width of the wavelength conversion device can be narrowed to 5 μmm or less, and therefore a small wavelength conversion device having approximately the same size as the nonlinear optical element 7 can be realized. [0046] [Embodiment 2] [0047] [0047]FIG. 2 is a plan view of a wavelength conversion device according to this embodiment. On a silicon substrate 5 (2 mm in width, 6 mm in length), electrodes 1 , 2 , and 3 are formed by patterning, and a DBR laser element 4 (0.3 mm in width, 1.2 mm in length) and a nonlinear optical element 7 (2.8 mm in width, 10 mm in length) are mounted in an integrated manner. Numeral 6 denotes an optical waveguide, and 8 denotes a diffraction grating formed in the optical waveguide 6 . Line 100 is a center line of the optical waveguide 6 . Line M 1 b -M 2 b is a center line of the width direction of the silicon substrate 5 , and line M 5 b -M 6 b is a center line of the width direction of the nonlinear optical element 7 . In this way, the construction of the wavelength conversion device in this embodiment is similar to that of the wavelength conversion device according to Embodiment 1, except that the silicon substrate 5 is miniaturized so that a length of a region where the DBR laser element 4 is mounted on the silicon substrate 5 is 3 mm along the longitudinal direction of the silicon substrate 5 , and the nonlinear optical element 7 is mounted on the substrate so that the center line 100 of its optical wavelength 6 is 0.7 mm away from the center line of the silicon substrate 5 . That is, in this embodiment also, the nonlinear optical element 7 is positioned within 3 μm of the DBR laser element 4 so as to introduce the laser beam emitted from the DBR laser element 4 securely, and the end of the optical waveguide 6 at the side where the SHG beam is emitted is located at least 5 μm beyond the edge of the silicon substrate 5 . Therefore, their explanations will be omitted. [0048] According to this embodiment, the same effects as in Embodiment 1 can be obtained. In addition, by reducing the length of the silicon substrate 5 , the region where the nonlinear optical element 7 is mounted on the silicon substrate 5 is narrowed. Therefore, distortion generated due to the contact between the nonlinear optical element 7 and the silicon substrate 5 can be reduced, and a conversion efficiency from the laser beam emitted from the DBR laser element 4 into the SHG beam can be improved. [0049] [Embodiment 3] [0050] [0050]FIG. 3 is a plan view of a wavelength conversion device according to this embodiment. On a silicon substrate 5 (3.0 mm in width, 12 mm in length), electrodes 9 , 10 , and 11 are formed by patterning, and a DBR laser element 4 (0.3 mm in width, 1.2 mm in length) and a nonlinear optical element 7 (2.8 mm in width, 10 mm in length) are mounted in an integrated manner. Numeral 6 denotes an optical waveguide, and 8 denotes a diffraction grating formed in the optical waveguide 6 . Line 100 is a center line of the optical waveguide 6 . Line M 1 c -M 2 c is a center line of the width direction of the silicon substrate 5 , and line M 5 c -M 6 c is a center line of the width direction of the nonlinear optical element 7 . [0051] The DBR laser element 4 is made up of three regions including a gain region, a phase control region, and a DBR region. [0052] With respect to these three regions, electrodes that are electrically isolated from one another are formed (not illustrated). The DBR laser element 4 is mounted on the silicon substrate 5 in a junction down manner where a surface with the p-n junction faces to the side of the silicon substrate 5 , and electrodes corresponding to the gain region, the phase control region, and the DBR region are bonded to regions 9 b, 10 b , and 11 b of the electrodes 9 , 10 , and 11 , respectively. [0053] Also, wire-bonding regions 9 a , 10 a , and 11 a are formed in each of the electrodes 9 , 10 , and 11 for carrying out wiring with an external power source so as to electrically drive the gain region, the phase control region, and the DBR region of the DBR laser element 4 . Here, widths of portions formed between these wire-bonding regions and regions 9 b , 10 b , and ll b (hereinafter, refered to as “connection regions”, which are connected to the respective electrodes formed in the three regions in the DBR laser element 4 ) are narrower than those of the wire-bonding regions and the connection regions. In this way, by partially narrowing the width of each of the electrodes formed on the silicon substrate 5 , the parasitic capacitance of these electrodes can be reduced. [0054] As stated above, the construction of the wavelength conversion device according to this embodiment is similar to that of the wavelength conversion device according to Embodiment 1, except that the width of each electrode formed on the silicon substrate 5 is narrowed in part, and the nonlinear optical element 7 is mounted on the substrate so that the center line 100 of its optical wavelength 6 is 1.0 mm away from the center line of the silicon substrate 5 . That is, in this embodiment also, the nonlinear optical element 7 is positioned within 3 μm of the DBR laser element 4 , and the end of the optical waveguide 6 at the side where the SHG beam is emitted is located at least 5 μm beyond the edge of the silicon substrate 5 . Therefore, their explanations will be omitted. [0055] According to this embodiment, the same effects as in Embodiment 1 can be obtained. In addition, by partially narrowing the width of each electrode formed on the silicon substrate 5 , the parasitic capacitance of these electrodes can be reduced, and therefore an electrical modulation frequency of the DBR laser element 4 can be increased. [0056] [Embodiment 4] [0057] [0057]FIG. 4 is a plan view of a wavelength conversion device according to this embodiment. On a silicon substrate 5 (2.0 mm in width, 6.0 mm in length), electrodes 9 , 10 , and 11 are formed by patterning, and a DBR laser element 4 (0.3 mm in width, 1.2 mm in length) and a nonlinear optical element 7 (2.8 mm in width, 10 mm in length) are mounted in an integrated manner. Numeral 6 denotes an optical waveguide, and 8 denotes a diffraction grating formed in the optical waveguide 6 . Line 100 is a center line of the optical waveguide 6 . Line M 1 d -M 2 d is a center line of the width direction of the silicon substrate 5 , and line M 5 d -M 6 d is a center line of the width direction of the nonlinear optical element 7 . [0058] The DBR laser element 4 is made up of three regions including a gain region, a phase control region, and a DBR region. [0059] With respect to these three regions, electrodes that are electrically isolated from one another are formed (not illustrated). The DBR laser element 4 is mounted on the silicon substrate 5 in a junction down manner where a surface with the p-n junction faces to the side of the silicon substrate 5 , and electrodes corresponding to the gain region, the phase control region, and the DBR region are bonded to regions 9 b , 10 b , and 11 b of the electrodes 9 , 10 , and 11 , respectively. [0060] Also, wire-bonding regions 9 a , 10 a , and 11 a are formed in each of the electrodes 9 , 10 , and 11 for carrying out wiring with an external power source so as to electrically drive the gain region, the phase control region, and the DBR region of the DBR laser element 4 . Here, widths of portions formed between these wire-bonding regions and regions 9 b , 10 b , and 11 b (hereinafter, referred to as “connection regions”, which are connected to the respective electrodes formed in the three regions n the DBR laser element 4 ) are narrower than those of the wire-bonding regions and the connection regions. In this way, by partially narrowing the width of each of the electrodes formed on the silicon substrate 5 , the parasitic capacitance of these electrodes can be reduced. As stated above, the construction of the wavelength conversion device according to this embodiment is similar to that of the wavelength conversion device according to Embodiment 1, except that the silicon substrate 5 is miniaturized so that a length of a region where the DBR laser element 4 is mounted on the silicon substrate 5 is 3 mm along the longitudinal direction of the silicon substrate 5 , the nonlinear optical element 7 is mounted on the substrate so that the center line 100 of its optical wavelength 6 is 0.7 mm away from the center line of the silicon substrate 5 , and the width of each electrode formed on the silicon substrate 5 is narrowed in part. That is, in this embodiment also, the nonlinear optical element 7 is positioned within 3 μm of the DBR laser element 4 , and the end of the optical waveguide 6 at the side where the SHG beam is emitted is located at least 5 μm beyond the edge of the silicon substrate 5 . Therefore, their explanations will be omitted. [0061] According to this embodiment, the same effects as in Embodiment 1 can be obtained. In addition, by reducing the length of the silicon substrate 5 , the region where the optical element 7 is mounted on the silicon substrate 5 is narrowed. Therefore, distortion generated in the optical waveguide 6 due to the contact between the nonlinear optical element 7 and the silicon substrate 5 can be reduced, and a conversion efficiency from the laser beam emitted from the DBR laser element 4 into the SHG beam can be improved. Furthermore, by partially narrowing the width of each electrode formed on the silicon substrate 5 , the parasitic capacitance of these electrodes can be reduced, and therefore an electrical modulation frequency of the DBR laser element 4 can be increased. [0062] [Embodiment 5] [0063] [0063]FIG. 5 is a plan view of a wavelength conversion device according to this embodiment. On a silicon substrate 112 (3 mm in width, 15 mm in length), electrodes 101 , 102 , 103 , 104 , 105 , and 106 are formed by patterning, and a DBR laser element 107 (0.3 mm in width, 1.2 mm in length) and a nonlinear optical element 115 (2.8 mm in width, 10 mm in length) are mounted in an integrated manner. Numeral 110 denotes an optical waveguide, and 111 denotes a diffraction grating formed in the optical waveguide 110 . Line 100 is a center line of the optical waveguide 110 . [0064] The DBR laser element 107 is made up of three regions including a gain region, a phase control region, and a DBR region. [0065] With respect to these three regions, electrodes that are electrically isolated from one another are formed (not illustrated). The DBR laser element 107 is mounted on the silicon substrate 112 in a junction down manner where a surface with the p-n junction faces to the side of the silicon substrate 112 , and electrodes corresponding to the gain region, the phase control region, and the DBR region are bonded to the electrodes 101 , 102 , and 103 (hereinafter called “connection electrodes”), respectively. [0066] Electrodes 104 , 105 , and 106 are wire-bonding electrodes for carrying out wiring with an external power source so as to electrically drive the gain region, the phase control region, and the DBR region, respectively. Then, these wire-bonding electrodes and the connection electrodes formed corresponding to the respective regions in the DBR laser element 107 are connected with each other by wires 13 a , 13 b , and 13 c , respectively. In this state, by feeding an electrical signal to each of the connection electrodes, an oscillation wavelength of the laser beam emitted from the DBR laser element 107 can be varied. The oscillation wavelength of the laser beam emitted from the DBR laser element 107 is set at 820 nm, and the beam is oscillated in the single longitudinal mode. [0067] The nonlinear optical element 115 is made of LiNbO 3 , and the optical waveguide 110 having the diffraction grating 111 is formed therein. The nonlinear optical element 115 is fixed onto the silicon substrate 112 at a predetermined position with an adhesive such as a UV curing agent. [0068] The diffraction grating 111 is formed by inverting a polarization of LiNbO 3 crystals with the application of an external electric field. The optical waveguide 110 is positioned within 3 μm of the DBR laser element 107 so as to introduce the laser beam emitted from the DBR laser element 107 securely. [0069] When guiding the laser beam through the optical waveguide 110 , an SHG beam with a wavelength of 410 nm generated due to a diffraction by the diffraction grating 111 and the laser beam with an oscillation wavelength of 820 nm are quasi-phase matched. Thereby, an SHG beam having a high output power can be obtained. In addition, by controlling the oscillation wavelength of the laser beam emitted from the DBR laser element 107 , a conversion efficiency from the laser beam into the SHG beam can be improved. [0070] In this embodiment, the DBR laser element 107 , the optical waveguide 110 of the nonlinear optical element 115 , and the electrodes 101 through 106 are arranged on the line 100 on the silicon substrate 112 . [0071] Furthermore, the end of the optical waveguide 110 in the nonlinear optical element 115 at the side where the SHG beam is emitted is located at least 5 μm beyond the edge of the silicon substrate 112 . This construction prevents the SHG beam from being reflected from the silicon substrate 112 and scattered, and therefore a favorable image can be obtained in the far field for the SHG beam emitted from the nonlinear optical element 115 . [0072] According to this embodiment, since the DBR laser element 107 , the optical waveguide 110 of the nonlinear optical element 115 , and the electrodes 101 through 106 are arranged on the line 100 on the silicon substrate 112 , the width of the wavelength conversion device can be narrowed to 5 mm or less, and therefore a wavelength conversion device having a width approximately the same as the width of the nonlinear optical element 115 can be obtained. [0073] [Embodiment 6] [0074] [0074]FIG. 6 is a plan view of a wavelength conversion device according to this embodiment. The construction of the wavelength conversion device according to this embodiment is similar to that of the wavelength conversion device according to Embodiment 5, except that the length of the silicon substrate 112 is made 6 mm, which is less than half the length of the silicon substrate 112 in Embodiment 5 (15 mm), and that a length of a region where the DBR laser element 107 is mounted on the silicon substrate 112 is 3 mm along the longitudinal direction of the silicon substrate 112 . That is, in this embodiment also, the nonlinear optical element 115 is positioned within 3 μm of the DBR laser element 107 . Therefore, their explanations will be omitted. [0075] According to this embodiment, the same effects as in Embodiment 5 can be obtained. In addition, by reducing the length of the silicon substrate 112 , the silicon substrate 112 can be miniaturized, and therefore the wavelength conversion device can be miniaturized and the cost can be reduced. Furthermore, by narrowing the region where the optical element 115 is mounted on the silicon substrate 112 , distortion of the optical waveguide 110 generated due to the contact between the nonlinear optical element 115 and the silicon substrate 112 can be reduced, and a conversion efficiency from the laser beam emitted from the DBR laser element 107 into the SHG beam can be improved. [0076] [Embodiment 7] [0077] [0077]FIG. 7 is a plan view of a wavelength conversion device according to this embodiment. The construction of the wavelength conversion device according to this embodiment is similar to that of the wavelength conversion device according to Embodiment 6, except that the width of the silicon substrate 112 is made to be 2.5 mm, which is narrowed by 0.5 mm versus that in Embodiment 6 (3 mm). That is, in this embodiment also, a length of a region where the DBR laser element 107 is mounted on the silicon substrate 112 is 3 mm along the longitudinal direction of the silicon substrate 112 , and the nonlinear optical element 115 is positioned within 3 μm of the DBR laser element 107 . Therefore, their explanations will be omitted. [0078] According to this embodiment, the same effects as in Embodiment 6 can be obtained. In addition, the silicon substrate 112 further can be miniaturized, and therefore the wavelength conversion device can be miniaturized and the cost can be reduced. [0079] [Embodiment 8] [0080] [0080]FIG. 8 is a plan view of a wavelength conversion device according to this embodiment. On a silicon substrate 112 (3 mm in width, 15 mm in length), electrodes 101 , 102 , 103 , 104 , 105 , and 106 are formed by patterning, and a DBR laser element 107 (0.3 mm in width, 1.2 mm in length) and a nonlinear optical element 115 (1.5 mm in width, 10 mm in length) are mounted in an integrated manner. Numeral 110 denotes an optical waveguide, and 111 denotes a diffraction grating formed in the optical waveguide 110 . Line 100 is a center line of the optical waveguide 110 . Line M 100 -M 200 is a center line of the width direction of the silicon substrate 112 and line M 500 -M 600 is a center line of the width direction of the nonlinear optical element 115 . [0081] In this embodiment, the DBR laser element 107 , the optical waveguide 110 of the nonlinear optical element 115 , and the electrodes 101 through 106 are arranged on the line 100 on the silicon substrate 112 , and connection wires 13 a , 13 b , and 13 c are connected to the electrodes 101 through 103 at the same side thereof so as to extend in the longitudinal direction of the silicon substrate 112 . Also, the width of the silicon substrate 112 is made to be 2 mm, which is narrowed by 0.5 mm versus that in Embodiment 7 (2.5 mm). [0082] In addition, the nonlinear optical element 115 is mounted on the silicon substrate 112 in such a manner that the center line 100 of its optical waveguide 110 is 0.5 mm away from the center line M 100 -M 200 of the silicon substrate 112 and 0.3 mm away from the center line M 500 -M 600 of the nonlinear optical element 115 . Thereby, the width of the nonlinear optical element 115 is narrowed further to 1.5 mm from 2.0 mm. [0083] In the same manner as in Embodiment 7, a length of a region where the DBR laser element 107 is mounted on the silicon substrate 112 is 3 mm along the longitudinal direction of the silicon substrate 112 , and the nonlinear optical element 115 is positioned within 3 μm of the DBR laser element 107 . [0084] According to this embodiment, the same effects as in Embodiment 7 can be obtained. In addition, with the construction where the connection wires 13 a , 13 b , and 13 c are connected to the electrodes 101 through 103 at the same side thereof on the silicon substrate 112 , and the nonlinear optical element 115 is mounted on the silicon substrate 112 in such a manner that the optical waveguide 110 is away from the center line M 100 -M 200 of the silicon substrate 112 and away from the center line of the nonlinear optical element 115 , regions where any components and wires are not formed on the silicon substrate 112 can be reduced, and the width of the silicon substrate 112 can be narrowed, and therefore a wavelength conversion device using the same can be miniaturized. [0085] [Embodiment 9] [0086] [0086]FIG. 9 is a plan view of a wavelength conversion device according to this embodiment. On a silicon substrate 212 (3 mm in width, 15 mm in length), electrodes 201 , 202 , 203 , 204 , and 205 are formed by patterning, and a DBR laser element 207 (0.3 mm in width, 1.2 mm in length) and a nonlinear optical element 215 (2.8 mm in width, 10 mm in length) are mounted in an integrated manner. Numeral 210 denotes an optical waveguide, and 211 denotes a diffraction grating formed in the optical waveguide 210 . Line 100 is a center line of the optical waveguide 210 . [0087] The DBR laser element 207 is made up of three regions including a gain region, a phase control region, and a DBR region. [0088] With respect to these three regions of the DBR laser element 207 , electrodes that are electrically isolated from one another are formed (not illustrated). The DBR laser element 207 is mounted on the silicon substrate 212 in a junction down manner where a surface with the p-n junction faces to the side of the silicon substrate 212 , and electrodes corresponding to the gain region, the phase control region, and the DBR region are bonded to the electrodes 201 , 202 , and 203 (connection electrodes), respectively. [0089] Electrodes 204 and 205 are wire-bonding electrodes for carrying out wiring with an external power source so as to electrically drive the gain region, the phase control region, and the DBR region, respectively. Then, these wire-bonding electrodes and the connection electrodes formed corresponding to the respective regions in the DBR laser element 207 are connected with each other by wires 214 and 213 . Here, the wire 214 is connected to the gain region, and the wire 213 is connected to the phase control region and the DBR region. The wire 214 is made of metal, and the wire 213 is made of p-type polysilicon with a resistor 213 a formed at a portion thereof. [0090] In this state, by feeding an electrical signal to each of the connection electrodes, an oscillation wavelength of the laser beam emitted from the DBR laser element 207 can be varied. By varying a voltage applied across the electrode 205 , a current fed into the gain region in the DBR laser element 207 can be controlled, and thus an output power of the laser beam can be controlled. The oscillation wavelength of the laser beam emitted from the DBR laser element 207 is set at 820 nm, and the beam is oscillated in the single longitudinal mode. [0091] The nonlinear optical element 215 is made of LiNbO 3 , and the optical waveguide 210 having the diffraction grating 211 is formed therein. The nonlinear optical element 215 is fixed onto the silicon substrate 212 at a predetermined position with an adhesive such as a UV curing agent. [0092] The diffraction grating 211 is formed by inverting a polarization of LiNbO 3 crystals with the application of an external electric field. The optical waveguide 210 is positioned within 3 μm of the DBR laser element 207 so as to introduce the laser beam emitted from the DBR laser element 207 securely. [0093] When guiding the laser beam through the optical waveguide 210 , an SHG beam with a wavelength of 410 nm generated due to a diffraction by the diffraction grating 211 and the laser beam with an oscillation wavelength of 820 nm are quasi-phase matched. Thereby, an SHG beam having a high output power can be obtained. In addition, by controlling the oscillation wavelength of the laser beam emitted from the DBR laser element 207 , a conversion efficiency from the laser beam into the SHG beam can be improved. [0094] In this embodiment, the DBR laser element 207 , the optical waveguide 210 of the nonlinear optical element 215 , and the electrodes 201 through 205 are arranged on the line 100 on the silicon substrate 212 . With this construction, the width of the wavelength conversion device can be narrowed to 5 mm or less, and a small wavelength conversion device having approximately the same width as the nonlinear optical element 215 can be realized. [0095] By providing the DBR laser element 207 with the phase control region, in addition to the gain region and the DBR region, so-called mode hopping can be prevented, and thus the oscillation wavelength can be controlled continuously. Unlike the gain region, the phase control region is a region from which gain is not obtained by the passage of electric current. In addition, the phase control region does not have a wavelength selectivity, because it is not provided with a diffraction grating as in the DBR region. When passing electric current through the phase control region, an effective refractive index in the optical waveguide within the region varies, and therefore a phase of the laser beam at a resonant state can be changed. [0096] [0096]FIG. 13 is a graph showing a relationship among oscillation longitudinal mode orders, amount of current fed into the phase control region and the DBR region in an AlGaAs class laser element. When injecting an electric current into the DBR region, the effective refractive index is increased, and the Bragg wavelength is shifted to the long wavelength side. Therefore, the oscillation longitudinal mode order mode-hops from the N-th to N−1-th, i.e., to the lower order. Meanwhile, when injecting an electric current into the phase control region, the effective refractive index is increased, and the effective cavity length is increased. Therefore, the oscillation longitudinal mode order mode-hops from the N-th to N+1-th, i.e., to the higher order. [0097] Consequently, as shown by the broken line in FIG. 13 where a ratio of the current injected into the DBR region to that into the phase control region is kept constant, when injecting an electrical current into the DBR region, the Bragg wavelength is shifted to the long wavelength side, and the oscillation wavelength whose mode gain is the highest is shifted to the long wavelength side. When injecting an electric current into the phase control region, the effective refractive index in this region is increased, and the effective resonator length is increased. Therefore, even when the oscillation wavelength shifts to the longer wavelength side, the oscillation at the same N-th longitudinal mode can be kept in the same phase state, and thus mode hopping can be prevented. [0098] [0098]FIG. 14 is a circuit diagram showing a state where resistors are connected in series to each of the phase control region 401 a and the DBR region 401 b in the semiconductor laser device 401 and the respective regions are driven with the same bias voltage applied by the power source 404 . In such a state, current injected into the phase control region and the DBR region has the relationship as represented by the following formula (1). I DBR =( R 2 +R DBR )/( R 1 +R PHASE )× I PHASE   (1) [0099] Here, I PHASE and I DBR are currents injected into the phase control region and the DBR region, respectively. R 1 and R PHASE are a value of differential resistance of the phase control region (constant value) and a value of resistance of the resistor 402 connected to the phase control region, respectively, while R 2 and RDBR are a value of differential resistance of the DBR region (constant value) and a value of resistance of the resistor 403 connected to the DBR region, respectively. [0100] Therefore, as shown by Formula (1), by varying the values of R PHASE and R DBR connected to the phase control region and the DBR region, a ratio between the current I DBR and I PHASE (i.e., (R 2 +R DBR )/(R 1 +R PHASE ), hereinafter, referred to as a ratio between currents) can be controlled. [0101] In this embodiment, as shown in FIG. 9, the resistor 213 a is formed at a portion of the wire connected between the phase control region and the DBR region in the semiconductor laser device. Assuming that the resistor 213 a has a value of resistance represented by R, the ratio between currents becomes I DBR /I PHASE =(R 2 +R)/(R 1 +R). Therefore, by adjusting the value R of the resistor 213 a so that the oscillation longitudinal mode orders does not generate mode-hopping, the oscillation wavelength of the laser beam emitted from the semiconductor laser device can be varied continuously. Note here that the value of R preferably is set within a range between 10 −3 Ω·cm and 10 6 Ω·cm. [0102] According to this embodiment, by providing a portion of the wire connected between the phase control region and the DBR region with a function as a resistor and adjusting the value of the resistor, the oscillation wavelength of the laser beam emitted from the semiconductor laser device can be controlled with stability. [0103] [Embodiment 10] [0104] [0104]FIG. 10 is a plan view of a wavelength conversion device according to this embodiment. The construction of the wavelength conversion device is similar to that of the wavelength conversion device according to Embodiment 9, except that the length of the silicon substrate 212 in the longitudinal direction is made to be 6 mm, which is a half or less of the length in Embodiment 9 (15 mm), the length of a region where the DBR laser element 207 is mounted on the silicon substrate 212 in the longitudinal direction of the silicon substrate 212 is 3 mm, and the width of the silicon substrate 212 is made to be 2 mm, which is narrowed by 1 mm from the width of the silicon substrate 212 in Embodiment 9 (3 mm). That is, in this embodiment also, the nonlinear optical element 215 is positioned within 3 μm of the DBR laser element 207 . Therefore, their explanations will be omitted. [0105] According to this embodiment, the same effects as in Embodiment 9 can be obtained. In addition, by reducing the length of the silicon substrate 212 , the silicon substrate 212 can be miniaturized, and therefore the wavelength conversion device can be miniaturized and the cost can be reduced. Furthermore, by narrowing the region where the optical element 215 is mounted on the silicon substrate 212 , distortion of the optical waveguide 210 generated due to the contact between the nonlinear optical element 215 and the silicon substrate 212 can be reduced, and a conversion efficiency from the laser beam emitted from the DBR laser element 207 into the SHG beam can be improved. [0106] [Embodiment 11] [0107] [0107]FIG. 11 is a plan view of a wavelength conversion device according to this embodiment. On a silicon substrate 212 (3.2 mm in width, 11.5 mm in length), electrodes 221 , 222 , 223 , 224 , and 225 are formed by patterning, and a DBR laser element 227 (0.3 mm in width, 1.2 mm in length) and a nonlinear optical element 215 (3 mm in width, 10 mm in length) are mounted in an integrated manner. Numeral 210 denotes an optical waveguide, and 211 denotes a diffraction grating formed in the optical waveguide 210 . Line 100 is a center line of the optical waveguide 210 . Line M 10 a -M 20 a is a center line of the width direction of the silicon substrate 212 and line M 50 a -M 60 a is a center line of the width direction of the nonlinear optical element 215 . [0108] The DBR laser element 227 is made up of three regions including a gain region, a phase control region, and a DBR region. [0109] With respect to these three regions, electrodes that are electrically isolated from one another are formed (not illustrated). The DBR laser element 227 is mounted on the silicon substrate 212 in a junction down manner where a surface with the p-n junction faces to the side of the silicon substrate 212 , and electrodes corresponding to the gain region, the phase control region, and the DBR region are bonded to the electrodes 221 , 222 , and 223 (connection electrodes), respectively. [0110] Electrodes 224 and 225 are wire-bonding electrodes for carrying out wiring with an external power source so as to electrically drive the gain region, the phase control region, and the DBR region, respectively. Then, a wire 214 is connected between the electrodes 221 and 224 , and a wire 213 is connected among the electrodes 222 and 223 , and 225 . The wire 214 is made of metal, and the wire 213 is made of p-type polysilicon with a resistor 213 a formed at a portion thereof. [0111] In this state, by feeding an electrical signal to each of the connection electrodes, an oscillation wavelength of the laser beam emitted from the DBR laser element 227 can be varied. By varying a voltage applied across the electrode 224 , a current fed into the gain region in the DBR laser element 227 can be controlled, and thus an output power of the laser beam can be controlled. The oscillation wavelength of the laser beam emitted from the DBR laser element 227 is set at 820 nm, and the light is oscillated in the single longitudinal mode. [0112] The nonlinear optical element 215 is made of LiNbO 3 , and the optical waveguide 210 having the diffraction grating 211 is formed therein. The nonlinear optical element 215 is fixed onto the silicon substrate 212 at a predetermined position with an adhesive such as a UV curing agent. [0113] The diffraction grating 211 is formed by inverting a polarization of LiNbO 3 crystals with the application of an external electric field. The optical waveguide 210 is positioned within 3 μm of the DBR laser element 227 so as to introduce the laser beam emitted from the DBR laser element 227 securely. [0114] When guiding the laser beam through the optical waveguide 210 , an SHG beam with a wavelength of 410 nm generated due to a diffraction by the diffraction grating 211 and the laser beam with an oscillation wavelength of 820 nm are quasi-phase matched. Thereby, an SHG beam having a high output power can be obtained. In addition, by controlling the oscillation wavelength of the laser beam emitted from the DBR laser element 227 , a conversion efficiency from the laser beam into the SHG beam can be improved. [0115] In this embodiment, as shown in FIG. 11, the nonlinear optical element 215 is mounted on the substrate in such a manner that the center line 100 of its optical waveguide 210 is located 1.0 mm away from the center line M 10 a -M 20 a of the silicon substrate 212 . In this way, the optical waveguide 210 does not necessarily need to be formed on the center line M 50 a -M 60 a of the nonlinear optical element 215 . [0116] In addition, although the nonlinear optical element is mounted on the substrate in such a manner that the center line M 10 a -M 20 a of the silicon substrate 212 coincides with the center line M 50 a -M 60 a of the nonlinear optical element 215 , these center lines do not necessarily need to be aligned. [0117] Furthermore, the end of the optical waveguide 210 at the side of the optical waveguide 210 where the SHG beam is emitted is located at least 5 μm beyond the edge of the silicon substrate 212 . This construction prevents the SHG beam from being reflected from the silicon substrate 212 and scattered, and therefore a favorable image can be obtained in the far field for the SHG beam emitted from the nonlinear optical element 215 . [0118] In this embodiment, a resistor 213 a is formed at a portion of the wire connected between the phase control region and the DBR region of the semiconductor laser device. Due to the same principle as in Embodiment 9, by controlling the value R of the resistor 213 a so that the oscillation longitudinal mode orders do not generate mode-hopping, the oscillation wavelength of the laser beam emitted from the semiconductor laser device can be varied continuously. Note here that the value of R preferably is set within a range between 10 −3 Ω·cm and 10 6 Ω·cm. [0119] According to this embodiment, by providing a portion of the wire connected between the phase control region and the DBR region with a function as a resistor and controlling the value of the resistor, the oscillation wavelength of the laser beam emitted from the semiconductor laser device can be controlled with stability. [0120] In addition, since the nonlinear optical element 215 is mounted on the substrate in such a manner that its optical waveguide 210 is located away from the center line M 10 a -M 20 a of the silicon substrate 212 , the width of the wavelength conversion device can be narrowed to 5 mm or less, and therefore a small wavelength conversion device having approximately the same size as the nonlinear optical element 215 can be realized. As a result, the silicon substrate 212 further can be miniaturized, and therefore the wavelength conversion device can be miniaturized and the cost can be reduced. [0121] [Embodiment 12] [0122] [0122]FIG. 12 is a plan view of a wavelength conversion device according to this embodiment. On a silicon substrate 212 (2.0 mm in width, 6 mm in length), electrodes 221 , 222 , 223 , 224 , and 225 are formed by patterning, and a DBR laser element 227 (0.3 mm in width, 1.2 mm in length) and a nonlinear optical element 215 (2.8 mm in width, 10 mm in length) are mounted in an integrated manner. Numeral 210 denotes an optical waveguide, and 211 denotes a diffraction grating formed in the optical waveguide 210 . Line 100 is a center line of the optical waveguide 210 . Line M 10 b -M 20 b is a center line of the width direction of the silicon substrate 212 and line M 50 b -M 60 b is a center line of the width direction of the nonlinear optical element 215 . In this way, the construction of the wavelength conversion device in this embodiment is similar to that of the wavelength conversion device according to Embodiment 11, except that the silicon substrate 212 is miniaturized so that a length of a region where the DBR laser element 227 is mounted on the silicon substrate 212 is 3 mm along the longitudinal direction of the silicon substrate 212 , and the nonlinear optical element 215 is mounted on the substrate so that the center line 100 of its optical wavelength 210 is 0.7 mm away from the center line of the silicon substrate 212 . That is, in this embodiment also, the nonlinear optical element 215 is arranged within 3 μm from the DBR laser element 227 so as to securely introduce the laser beam emitted from the DBR laser element 227 . Therefore, their explanations will be omitted. [0123] According to this embodiment, the same effects as in Embodiment 11 can be obtained. In addition, by reducing the length of the silicon substrate 212 , the region where the nonlinear optical element is mounted on the silicon substrate 212 is narrowed. Therefore, distortion generated due to the contact between the nonlinear optical element 215 and the silicon substrate 212 can be reduced, and a conversion efficiency from the laser beam emitted from the DBR laser element 227 into the SHG beam can be improved. [0124] In the above-stated embodiments, the substrate is made of silicon. However, instead of silicon, materials such as SiC or AlN may be used. With these materials, thermal dissipation of the device can be improved, the operational current of the semiconductor laser device can be decreased, and the operational temperature range of the semiconductor laser device can be broadened. Alternatively, resin such as plastic may be used. If using a resin substrate, an electrical wiring pattern can be integrated on the substrate. As a result, a more light-weight, miniaturized, and low-cost wavelength conversion device can be obtained. [0125] In the above-stated embodiments, the nonlinear optical elements are made of LiNbO 3 . Instead, materials such as LiTaO 3 , KTiOPO 4 , and KNbO 3 may be used. [0126] In the above-stated embodiments, DBR laser elements are used as the semiconductor laser device. Instead, multielectrode driven type laser elements such as a multielectrode semiconductor laser device capable of a Fabry-Perot mode oscillation, a multielectrode Distributed Feedback (abbreviated as “DFB”) type laser element, a multielectrode bistable semiconductor laser element, and a pulse laser may be used. With these elements, the time dependency of the output power of the SHG beam can be lessened. Alternatively, instead of the DBR laser element, laser elements whose wavelength can be controlled may be used. [0127] In the above-stated embodiments, the semiconductor laser devices have three regions. However, insofar as the oscillation wavelength of the laser beam emitted therefrom can be controlled adequately, semiconductor laser devices having two regions or four or more regions may be used. [0128] If optical components such as a lens, birefringence material, prism, mirror, and an optical modulator may be integrated as the integrated components, in addition to the semiconductor laser device and the nonlinear optical element, a small wavelength conversion device can be obtained. [0129] Furthermore, the wires connecting components may be integrated on the silicon substrate directly. In the case of the substrate made of silicon, instead of metal, polycrystal silicon, p-type silicon, and n-type silicon can be used as a material of the wire. [0130] The invention may be embodied in other forms without departing from the spirit or essential characteristics thereof. The embodiments disclosed in this application are to be considered in all respects as illustrative and not limiting. The scope of the invention is indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.

A wavelength conversion device that converts a wavelength by second harmonic-wave generation and generates a laser beam, includes: a substrate having a plurality of electrodes; a semiconductor laser device mounted on the substrate and electrically connected to the plurality of electrodes; and a nonlinear optical element having an optical waveguide for guiding a laser beam emitted from the semiconductor laser device and for converting a wavelength of the laser beam. Here, the nonlinear optical element is mounted on the substrate so that the optical waveguide in the nonlinear optical element is located away from the center line of the substrate. Thereby, a small wavelength conversion device provided with a semiconductor laser device and a nonlinear optical element, which are mounted on the substrate in an integrated manner, can be obtained, and therefore an optical pickup unit in the optical disk employing this wavelength conversion device can be miniaturized.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a multi-purpose clamping apparatus for pressing the confronting edges or ends of two boards or other components during a gluing process. 2. Description of the Prior Art In the practice of woodwork crafting the occasion often arises where boards or other components of wood or composites or other man-made materials are to be joined together along proximate edges or ends to provide a composite frame, border or panel to be integrated into a piece of furniture or molding. For narrow slats and the like, conventional clamps and vises, having a bite sufficient to span the width of the boards or items being joined, are satisfactory to engage the opposite sides of such boards and press them firmly together at the edges to be joined. However, difficulty is encountered when the boards to be joined are collectively wider than the bite of a conventional vise. A challenge is also presented when the boards are to be joined endwise thus requiring gripping of the boards for application of compressive forces in the longitudinal direction. The challenges encountered are compounded when the boards to be joined are to project at various angles, such as 90° to one another. In practice, it is desirable to orient the components in edgewise contacting relation to secure the relative positioning so as to visually check the fit and then, if satisfactory, separate such components to space the components apart for access to the mating edges for application of glue while monitoring the relative component orientation for repeating the mating fit with the glued edges. Numerous differed devices have been proposed in effort to solve the problems encountered in joining wide boards together laterally, lay boards together endwise, and other boards together at various uncommon angles. One such mechanical device for clamping together of the confronting edges of boards during a gluing process incorporates a vise-like bar-clamp having two jaws at opposite ends of a bar that draw together boards placed in-between as the jaws are drawn together in a screw-like action. These vise-like clamping devices must more or less vary in size in direct relation to the composite span of the boards to be joined. Where large boards, such as plywood or particle board, or odd shapes, such as round stock, are used, the task of aligning the boards and clamping the boards in-between bar clamps can be burdensome indeed. One such clamping device proposed for joining wide boards edgewise includes a screw to draw two barrel nuts together that are inserted within pilot holes drilled into the boards. The joint is secured tightly by adjusting the screw between the two barrel nuts. While such a clamping device is not size dependent in relation to the scale of the boards, the device does require that pilot holes be drilled into the surface of the boards in order to secure barrel nuts. Drilling of these holes requires care and skill to avoid unwanted damage such as accidental drilling through to the opposite face and in any event leaves the unsightly holes visible in the finished product themselves. Moreover such devices are not adaptable for practical use in joining oddly configured components such as round stock or cylindrically shaped molding. Finally, for smaller pieces, an adjustable corner and splicing clamp has been employed consisting of a pair of vise-like clamps adjustably mounted on a protractor for clamping miter or butt joints at any selected angle as required. In a device of this type, the two vises are rotated into position along the protractor and the boards may be secured at their widths by the vises. While such devices work well for picture frames and the splicing of molding and trim, the vise clamps prove inadequate for securing larger boards together. Wood workers have from time to time been forced to rely on trial and error techniques which often include extensive shaving or sanding of the confronting edges prior to the application of glue to the confronting edges. None of the clamping devices or techniques of the prior art offer a practical device allowing for alignment of the boards to be glued to establish the desired orientation and alignment and then for separation to expose the confronting edges for application of glue or other bonding material while monitoring such established orientation and alignment for pressing of such boards back together without requiring that the boards be realigned. Thus a need exists for a universal clamping device that maybe applied to different sizes and configurations of components to be joined together, that does not affect or intrude upon the fit or the integrity of the boards and allows for adjustment of the boards while maintaining their alignment. SUMMARY OF THE INVENTION The clamping apparatus of the present invention is characterized by a pair of base plates formed with upwardly facing support surfaces for securing a pair of respective components thereon during the process of gluing their confronting edges together wherein each base plate includes respective clamps to maintain the respective boards fixed against the base plates. Included between the two base plates is a rail that couples the first and second base plates together and permits movement of the second base plate therealong permitting the two base plates, with the components affixed therein, to be separated apart for access of glue to the edges, and then to be pressed together without disturbing alignment of such components. A trigger shaped press, mounted on the second base plate, when actuated, incrementally draws the second base plate along the rail towards the first base plate firmly pressing the confronting edges of the two boards clamped thereon together. The present invention provides the opportunity to refine the confronting edges of the components and apply the glue after the boards have been securely aligned in the clamp. Once glue has been applied to the components, the press is actuated to draw the confronting edges together. It is a further object of this invention to permit the clamping apparatus to pivot the base plates about a pivot axis to allow for the angular displacement of the base plates to be adjusted according the joint angle formed by the connection of the two components. Other objects and features of the invention will become apparent from consideration of the following description taken into connection with the accompanying drawing. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a clamping apparatus embodying the present invention; FIG. 2 is a partial top plan view, in enlarged scale, taken along line 2--2 of FIG. 1; FIG. 3 is a top plan view similar to FIG. 2 showing the clamping apparatus rotated about its center axis; FIG. 4 is a top plan view similar to FIG. 2 showing the clamping apparatus rotated about its center axis opposite to FIG. 3; FIG. 5 is a transverse sectional view in enlarged scale, taken along line 5--5 of FIG. 1; FIG. 6 is a longitudinal front sectional view, in enlarged scale, taken along line 6--6 of FIG. 1; FIG. 7 is a transverse sectional view, in enlarged scale, taken along line 7--7 of FIG. 6; FIG. 8 is a partial longitudinal sectional view, taken along line 8--8 in FIG. 6; FIG. 9 is a transverse sectional view taken along line 9--9 of FIG. 6; FIG. 10 is a partial back view taken along line 10--10 of FIG. 9; and FIG. 11 is a longitudinal top view taken along line 11--11 of FIG. 9. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, the clamping apparatus of the present invention includes, generally, a pair of base plates 14 and which may be of a generally rectangular brick-like shape and pivotally connected together along an elongated rail 18 on which plate 16 slides. The base plates support respective upstanding C-clamps, generally designated 20 and 22, for selectively clamping components such as boards 23 to the respective top surfaces of such base plates 14 and 16. A friction press, generally designated 24, mounted in the base plate 16 controls movement of such plate relative to the base plate 14 and is operative to provide a mechanical advantage in selectively driving base plate 16 and, consequently, a component clamped thereon, toward the base plate 14. Thus, the plates 14 and 16 may be adjusted to a selected position such as that shown on FIG. 1 and components such as flat boards 23 and 25 positioned thereon in contacting edgewise relations, the clamps 20 and 22 closed to secure such components in relative mating position on such base plates. The press 24 may then be released to free the base plate 16 to slide on the rail 18 away from base plate 14 to expose the confronting edges of such components for application of glue. The base plate 16 may then be slid freely back on the rail 18 to shift the component 25 back into mating contact as previously established with component 23. The press 24 may then be activated to press the plate 16 toward the plate 14 to thoroughly press the edges of the components 23 and 25 firmly together while maintaining the previously established relationship. The main support for the components 23 and 25 is provided by the base plates 14 and 16 that consist of rectangular wooden blocks having an overall brick-like shape tapered at the corners of their proximal ends to form respective chamfers 26. The upper surface 27 of each of the blocks is textured or coated with a grit matting to prevent sliding of the components when placed on the blocks. The wooden blocks provide a firm rigid support surface for the components 23 and 25 that is lightweight and easy to manufacture. The use of wooden base plates also reduces the risk of damage to components 23 and 25 due to scratching during mounting of the components as would be encountered with metal base plates. Each of the base plates 14 and 16 include tapered corners 26 at their respective confronting proximal ends thereby reducing the surface area of the proximal end. With reference to FIGS. 1-4, 6 and 8, the first base plate 14 is formed at one extremity with a semi-cylindrical concavity 28 carved out of the upper half and a cylindrical tongue 30 projecting from the lower half and configured with the same radial center point as that of the concavity 28. On the upper surface of the first base plate 14, a central pointer mark 32 extends longitudinally to the edge of the concavity end to visibly identify the center point of the concavity 28. At the radial center point of the tongue, a bore hole 34 extends through the center of the tongue with a counter bore 36 on the underside of the tongue. A threaded bore hole 38 (FIG. 6) is drilled through the tongue at a point half way between the counter bore 36 and the proximal end 28 of the first base plate 14. The bore hole 38 threadably receives a set screw 40 terminating at its upper extremity in an index tip 42 projecting about the top surface of such tongue. It will be appreciated that the function of the index screw is only to establish a positive angular relationship between the base plates 14 and 16 and may take many different forms. The threaded bore 38 could be in the form of a blind bore drilled at the same location in the upper surface of the tongue and housing an open ended barrel having a retainer rim about the open end to retain a spring loaded index ball to be pressed into selective engagement with indents. With continued reference to FIGS. 1-4, 6 and 8, the proximal end of a second base plate 16 is shaped with a cylindrical concavity 44 that complements the curvature of the end of the cylindrical tongue 30 to be abutted thereagainst. Formed centrally along the longitudinal axis of base plate 16 is an open ended slot 46 (FIG. 6). The slot 46 may be of either rectangular or cylindrical in cross section. The distal extremity of the plate 16 is hollowed out to form a downwardly opening clamp chamber 48 (FIGS. 5 and 6). Referring to FIG. 6, a blind bore 50 is drilled longitudinally into the proximal end of the plate 16 centrally in the concavity 44 aligned under the slot 46 to receive an open ended barrel 52 having a retainer rim 54 about the open end. A ball bearing 56 is housed in the barrel to be biased against the rim 54 by means of a bias spring 58. A cylindrical disk 60 (FIGS. 1 and 6) having the same thickness and diameter as the tongue 30 of the first base plate 14 overlies the tongue and cooperates therewith to form a central hub 62. From a counter sunk cavity 64 on the upper side of the disk 60, a bore hole 66 extends through the cylindrical center of the disk and aligns with the bore hole 34 in the tongue 30. On the underside of the disk 60, a diametrical, open ended mortise 68 is carved to align with the end of the slot 46 (FIG. 6). Referring to FIG. 8, a plurality of index bores 70 and 72 are drilled into the underside of the disk and correspond to predetermined angular locations 90', 180' and 270' with respect to the radius formed by the mortise 68. The index bores 70 and 72 are all drilled on the same radius as the threaded bore 38 in the tongue 30 of base plate 14 so the set screw will, when clocked to the appropriate position, align therewith. Referring to FIGS. 1-4, protractor indicia 74 is printed about the periphery of the top side of the disk 60 to register with the pointer 32. The tension rail 18 telescopes from the tensioning chamber 48, through the slot 46 (FIG. 6) and into the mortise 68 and is formed with a bore 76 aligned with the tongue bore 34 and disk bore 66. A bolt 78 extends through the bores 66, 76 and 34 such that the head 80 of the bolt nests in the counter sunk cavity 64 in the disk 60 and a nut 82 is threadably secured to the bolt, housed in the counter sunk cavity 36 on the underside of the tongue. Although firmly secured, the rod 18 and disk 60 are free to pivot about the central bore hole with respect to the base plate tongue 30. A pistol-handled friction press 24 (FIG. 5) is housed in the chamber 48 of the base plate 16 and secured by a pair of wood screws 84. While friction press 24 may take many different forms, the one selected for illustration is similar in design to the trigger presses found on commercially available caulking guns. A rectangular frame 86 is housed within the chamber 48 formed at the backside proximal corner with a pistol handle 88 that extends laterally out of the backside opening 90 in the cavity. The rectangular frame 86 includes a thick rim 92 that extends from the free end of the handle 88 along the proximal end of the frame to the front side distal corner 94 of the frame opposite from where the handle begins. When viewed laterally, the handle and rim combine to exhibit a T-shape appearance that structurally enhances the handle to withstand the torque forces applied to it by the craftsman's grasp. The rim side of the handle is contoured to ease in gripping the handle. The rod 18 is inserted through the proximal end of the second base plate with the free end 96 of the rod 18 extending out the distal end. The rectangular frame 86 receives the rod 18 through a longitudinal slot 98 formed in the frame where at the receiving end of the frame a spring biased friction latch 100 and release 102 is secured to the frame by an overhanging lip 104 or J-hook projecting longitudinally away from the front side corner of the frame 86. The friction latch 100 includes a vertically extended oval shaped aperture (not shown) with a lower edge that is biased by a spring 106 to frictionally grip the underside 108 of the rod to prevent withdrawal of the second base plate toward the free end of the rod. A latch release 102 is connected to the friction latch 100 with a free end that extends out of the second base plate 16 in spaced apart relation to the handle 88 such that, when sufficient pressure to counter the spring bias is applied to the release 102, the lower end of the friction latch 100 is drawn towards the handle thus freeing the rod from the lower edge of the aperture. A release stop 110 extends horizontally out of the lower corner of the frame to stop the friction latch at the point where the rod is freed therefrom. A trigger 112 (FIG. 5) pivotally carried from the frame near the base of the handle includes a trigger grip 114 molded with finger contours that diverges out from the handle base such that the free end of the trigger 112 is in spaced apart relation with the free end of the handle 88. Side supports 116 on the trigger slide over opposite sides of the frame 86 and a cross-member 118 pivotally connects the trigger to the frame. A second cross member 120 bolts to the free ends of the trigger side supports 116. A spring biased friction press 124, located within an aperture 122 in the frame 86, is biased against the second cross member 120 by a spring 123 and receives the rod through a vertically extended oval aperture in the friction press. Referring to FIGS. 1 and 9-11, respective upstanding C-clamps 20 and 22 are mounted on the base plates by a pair of bolts 126 securing the respective clamps 20 and 22 to the base plates 14 and 16. With reference to the second base plate clamp 22, an upstanding T-shaped neck 128 rises above the upper surface of the base plate 16 onto which a boss 130 is mounted in overlying relation to the upper surface 27 of the base plate. The boss 130 includes a threaded bore 132 (FIG. 11) supporting a screw 134 therein. A handle 136 (FIG. 9) is attached to the upper end of the screw and a foot 138 couples to the lower end of the screw. The foot is generally in the shape of a horizontal tombstone (FIG. 11) having a rounded front end 140 to receive wood stock 25 without damaging the wood stock against sharp corners. Carried from the rear end of the foot a pair of rearwardly projecting inturned cleats 142 slidingly capture the outer edges 144 of the upstanding neck. Formed in the underside of the foot, a V-groove 146 extends width-wise across the foot to accommodate the periphery of round stock, alternatively the grooves could be formed in the top surface of the underlying base plates. In operation, a wood worker must first prepare the clamping apparatus for the task at hand. If frames or oddly shaped components are to be joined, then the base plates 14 and 16 may be pivoted to the corresponding angle formed by the joined components 23 and 25. The base plates may be pivotally rotated to any angle within 90 degrees on either side of each other. The tapered clearance corners 26 on the proximate ends of the base plates 14 and 16 allow this increased range of rotation about the hub 62. The index mark 32 and protractor indicia 74 cooperate to allow the wood worker to exactly align the base plates 14 and 16 to the necessary joint angle. Once the angle between the base plates has been achieved, the angle may be secured by rotating the set screw 40 until its tip 42 contacts the disk 60 above the tongue 30. Index bores 70 and 72 in the disk 60, located at the most often used pivot angles, receive the tip 42 of the set screw 40 thereby locking the angular displacement of the base plates securely in the selected angle. Once the desired angle has been selected, the release 102 on the second base plate 16 is drawn towards the handle 88 of the friction press 24 to allow the rail 18 to telescope freely through the second base plate 16 thus allowing the second base plate 16 to be adjusted in a slight spaced apart relationship to the hub 62. Finally, the respective clamp handles 136 are rotated until each foot 138 is raised sufficiently away from the upper surface 27 of the base plates to receive the components 23 and 25 in between. Once the clamping device has been properly adjusted, the respective components 23 and 25 to be joined are placed on the textured upper surface 27 of the base plates. The confronting edges are positioned in contact with one another and the C-clamps 20 and 22 are closed to secure the respective components against the upper surface 27 of the base plates 14 and 16. It will be appreciated that the spacer ball 54 will serve to maintain the base plate 16 spaced distally from the tongue 30 and hub disk 32 by about 1/16 of an inch even though the edges of the boards 23 are in intimate contact. The press may be released so the plate 16 can be freely slid thereon away from the plate 14 to space the adjacent edges of the boards 23 and 25 apart so ready access can be had thereto. Glue may then be applied to the spaced apart edges of the board and the friction press 24 actuated to release the grip on the rail 18 to free the plate 18 so it can be slid toward the hub. The press may then be operated to incrementally draw the base 16 toward the plate 14 thus retracting the spacer ball 54 into the barrel 50 (FIG. 6) to provide for the components 23 and 25 to be drawn firmly together. By incrementally drawing the base plates together, the craftsman is able selectively chose the necessary amount of pressure to be applied to the confronting edges of the respective components thereby insuring that all of the glue is not squeezed out of the joint by the clamping device. When the components have dried, the clamps 20 and 22 are opened and the joined components removed. It will be appreciated that with the articulation capability about the hub, the plate 16 may be selectively rotated about such hub to the position shown in FIG. 3 so that the respective clamps are positioned facing outwardly at 90° from one another. It will be appreciated by those skilled in the art that, in this orientation, the clamp apparatus may be conveniently fitted into the inside corner of, for instance, a frame with 90° corners to thus clamp the adjacent frame components by such clamp so they may be drawn together by the press. Similarly, in the orientation shown in FIG. 4, the clamps 20 and 22 will be facing inwardly so they may be clamped over the outside edges of 90° frame components so the press may be utilized to draw such components together from the outside. From the foregoing, it will be apparent that the clamp apparatus of the present invention is economical to make, convenient to operate and effective to provide for effective pressing together of odd configured or particularly wide components. Various modifications and changes may be made with regard to the foregoing detailed description without departing from the spirit of the invention.

A multi-purpose clamping apparatus to join the confronting edges of two boards together during a gluing process having a pair of base plates, a central hub about which the base plates may be rotated, a rail projecting laterally from the hub on which one of the base plates is connected and a press mounted on one of the base plates and engaging the rail for drawing the base plates together. Respective clamps overlie the upper surface of the base plates.

[0001] This Application is a Continuation of currently pending PCT/IB2010/050784 filed Feb. 23, 2010, which Application claims priority of Spanish Patent Application P200900505 filed Feb. 24, 2009. FIELD OF THE INVENTION [0002] The present invention relates to a method for reducing interstitial elements in cast alloys. Specifically, it relates to a method for reducing hydrogen in steel castings. The present invention also relates to a system for performing this method, which can be integrated into a mold or a continuous casting system. BACKGROUND OF THE INVENTION [0003] Throughout this document, the term interstitial elements refers to those atoms that, because of their small size with respect to the main elements in the alloy, are able to diffuse interstitially, that is, via the spaces in the metallic crystalline lattice, without the need to displace other atoms from their positions in the lattice. In the case of many alloys, like steel, atoms like hydrogen, nitrogen carbon and others can act like interstitial elements. [0004] It is known that hydrogen is an interstitial element that can cause the embrittlement of steel components. Specifically, the sensitivity to hydrogen embrittlement is more evident in high-strength alloys. [0005] Various mechanisms have been described as responsible for said embrittlement. These mechanisms do not begin to materialize as long as the temperature does not drop below a given threshold so that the interstitial elements in question feature a reduced mobility and an insufficient solubility, and tend to combine with other elements to form embrittling compounds. [0006] It is known that hydrogen features a solubility which varies from one metallurgical phase to another and at the same time, solubility increases within each phase as temperature increases. For example, in the case of the solid phases of steel, hydrogen solubility ranges between 8 ppm in high temperature austenite (1400° C.), and less than 1 ppm in room temperature ferrite, and it is approximately 30 ppm in the liquid phase at 1600° C. [0007] It can be considered that the phenomenon of diffusion of interstitial elements is governed mainly by the interstitial atom's thermal agitation within the crystalline lattice, i.e., at higher temperatures, greater thermal agitation and, therefore, greater probability of diffusion. Although the situation usually considered is the diffusional flux occurring from high concentration regions towards regions of lower concentration this is not the only possible scenario. Rigorously, the driving force behind diffusional fluxes is the free energy reduction of the system. To be still more precise, diffusion occurs from areas of high chemical potential to areas of lower chemical potential. [0008] Nevertheless, it can be shown that whenever the atomic mobility is sufficient, and in absence of composition differences or other factors which could cause a more important flux, a high temperature gradient also causes a net flux of interstitial elements towards higher temperature regions. This effect is produced because, on the one hand, as regions at higher temperature are in a state of lower saturation, as they feature greater solubility, and therefore they would have a lower chemical potential than regions at higher saturation in the same temperature conditions. On the other hand, the flux towards high temperature regions is encouraged by the increase in atomic mobility as the temperature increases. [0009] The presence of hydrogen in metallic alloys, especially in steels, is due to several reasons, from the presence of humidity in the raw materials or equipment or the decomposition of compounds present in the later, as well as actions performed during the alloy casting and refining process, for example those where hydrogen is blown through the molten metal with the aim of eliminating other elements, with the final consequence that some fraction of the hydrogen used remains dissolved in the molten metal. [0010] During the casting process, heat extraction from the metal occurs through the walls of the mold and from the free surfaces of the cast metal. [0011] In this manner, the cast metal generally cools from the surface to the core of the casting. That is, the casting's core remains at higher temperature than its surface, producing an increasing temperature gradient from the surface towards the core. [0012] This marked temperature gradient, at temperatures at which interstitial elements such as hydrogen still feature a high mobility, produces a flux of interstitial elements towards the casting core, due to its higher temperature and greater capacity to dissolve said elements with respect to the adjacent regions which are at lower temperatures. [0013] This diffusive flux tends to concentrate the total content of the interstitial element in question in the core region of the casting. [0014] Due to the damaging effect of hydrogen in the mechanical properties of the components produced, traditionally different systems have been used to eliminate it. [0015] These systems can be divided into two families: The use of certain additions during the refining process or the exposure of the molten metal to a reduced pressure. [0016] The first of these methods consists in the addition of refining elements or substances that would combine with hydrogen (or other elements) and form insoluble substances that could be then eliminated during the refining process. [0017] The second system consists in exposing the molten metal to an atmosphere with reduced pressure, as hydrogen solubility in the molten metal is function of pressure as well as of temperature and crystalline structure. [0018] This second system produces a better hydrogen elimination rate, although at the expense of a large increase in the investment for the necessary equipment. For its part, the first system entails a much smaller investment, but it has also a lower hydrogen reduction rate, so that it is much less effective. Furthermore, this first system has the added issue that implies the modification of the alloy composition. [0019] Therefore, the need is clear for a method which reduces interstitial elements, particularly hydrogen, in a casting process, without the modification of the alloy composition (with the exception of interstitial elements themselves) and furthermore, without requiring a large investment such as in the case of vacuum casting and refining. BRIEF SUMMARY OF THE INVENTION [0020] The previously discussed drawbacks are resolved by the method and the system of the invention, featuring other advantages which will be described below. [0021] According to one aspect, the method for reducing interstitial elements in alloy castings of the present invention comprises the steps of: injecting said alloy in a system for the formation of a casting or a continuous cast; allowing said alloy to cool; wherein at least a peripheral region of the casting is heated, so that the flux of interstitial elements occurs towards at least one the peripheral region. [0025] Consequence of this feature, a method is achieved where most of the interstitial elements concentrate in one or several regions in the surface region of the casting. Later on, such elements can easily be eliminated from these regions by means of a thermal surface treatment or surface machining of the casting. [0026] Preferably, at least one peripheral region is heated before the alloy cools to a temperature low enough for the formation of embrittling compounds. [0027] According to another aspect of the invention, at least one peripheral region is heated at a temperature between 900° C. and the melting point of the alloy. [0028] Such heating of each peripheral region is preferably maintained until any part of the piece, different than the peripheral regions, is at a temperature of less than 400° C. [0029] According to a further aspect of the invention, the interstitial elements are hydrogen, carbon, nitrogen, boron, argon, or other interstitial elements or other elements which feature high diffusivity in the alloy matrix, and said alloy is a steel alloy, iron, copper, nickel, titanium, cobalt, chrome or others with melting points greater than 800° C., as well as some alloys with lower melting points, such as aluminium alloys. [0030] According to still another aspect of the invention, the system for reducing interstitial elements in cast alloys comprises at least one heating element situated on the periphery of the cast. [0031] According to still a further aspect of the invention, each heating element is an electric resistor or an induction coil, and each heating element is complemented with a temperature sensor. [0032] According to sill another aspect, the complete system of the invention can be applied both to mold casting and continuous casting systems. BRIEF DESCRIPTION OF THE DRAWINGS [0033] The foregoing summary as well as the following detailed description of the invention will be best understood when considered in conjunction with the accompanying drawings, and wherein: [0034] FIGS. 1 and 2 are schematic views of a casting system according to the present invention, representing the flux of interstitial elements and the isothermal curves in the cast alloy; and [0035] FIG. 3 is a schematic view of a continuous casting system according to the present invention. DETAILED DESCRIPTION OF THE INVENTION [0036] It should be noted that although the present description corresponds to the case of hydrogen reduction during steel casting, the scope of application of the method of the present invention extends to any alloy casting wherein a reduction in the amount of dissolved hydrogen or of any other interstitial element is desired, such as, for example, carbon, nitrogen, boron and others. [0037] Unlike the method of the previously described techniques, according to the method of the present invention the existence of a increasing temperature gradient is forced and directed towards one or more points on the surface of the piece, so that the flux of interstitial elements occurs towards the surface, instead of towards the core of the casting. [0038] In this way, the interstitial elements will be eliminated from the casting by simple diffusion through the surface of the piece, and any remainder concentrates in a region close to the surface, so that it can easily be eliminated by means of a subsequent thermal surface treatment and/or surface machining of the casting. [0039] In order to obtain a temperature gradient favourable to force the interstitial element flux towards the surface of the casting, it is necessary to maintain at least one region of the surface of the casting at a sufficiently high temperature during the solidification and cooling process, so that it is maintained at a higher temperature than the rest of the casting till the end of the process. [0040] In the event of wanting to eliminate an element such as hydrogen, which tends to combine with other atoms, forming embrittling compounds, it is important to ensure that this method is initiated before the piece cools to temperatures at which said embrittling compound formation reactions occur. [0041] As observed in the figures, the system, in this case a mold, indicated generally by means of the numeric reference 1 , comprises a heating element 2 . [0042] It must be pointed out that even though one heating element 2 has been represented in the figures for the sake of simplicity, it is clear that there can be any suitable number of heating elements, depending on the shape and dimensions of the mold. [0043] The or each heating element 2 , which is integrated into the mold wall 1 and begins to actuate during the pouring of the molten alloy into the mold, can consist of an induction coil, duly protected from the liquid metal, or of an electric resistor, or any suitable heating element. [0044] One requirement of this heating element is that it must be built into the mold, at a distance which is sufficiently close to the inner surface of the mold and which reliably permits the region of the surface of the piece to be kept at a suitable temperature. [0045] Another essential requirement of the heating element is its capacity to endure temperatures higher than that of the alloy's melting point, and especially the thermal shock produced during the filling of the mold. [0046] For example, in the event of treating cast steel pieces, the temperature to be maintained can exceed 1400° C., and the temperature of the molten metal can exceed 1600° C. [0047] In the event that an electric resistor is used as a heating element, this can be built integrated into the wall of the mold, surrounded and protected for example by an alloy resistant to the temperature, or ceramic refractory material, or even integrated into the wall of the mold in the case of sand casting. [0048] Heating elements using an electric resistor are expected to be tougher and less expensive, and might require a simpler control system, than in the case of an induction coil, although they feature a larger heat lag. [0049] If the heating element is realised using an induction coil, the surrounding material must not be conductive in order to prevent the generation of induced currents, since these induced currents would heat the heating element or the walls of the mold, instead of the surface of the casting. [0050] Each heating element 2 is connected to a temperature sensor 3 , a control system 4 and an energy supply system 5 . [0051] The control system 4 is required to adjust the temperature of the heated peripheral region (or hot spot) and could be similar to those normally used for automated surface induction heat treatments. [0052] Additionally, the type and the placement of the temperature sensor 3 must be suitable to prevent the magnetic field generated by the induction coil from distorting the temperature measurement, and this must be situated so that it directly measures the temperature of the surface of the casting. [0053] In this sense, a heating element 2 based on an induction coil it is expected to require a slightly greater investment than that based on a resistor, but has the advantage that it permits a much quicker and precise modulation of the temperature obtained. [0054] An alternative embodiment to mold 1 of FIG. 1 has been represented in FIG. 3 , which depicts the application of he method to a continuous casting system. In this embodiment, the same numeric references have been maintained to identify elements equivalent to those in the previous embodiment. [0055] A continuous casting system 10 , whose main functioning is identical to that of the mold 1 , is represented in FIG. 3 . [0056] In this case, the molten metal is deposited in a distribution tank 11 , wherefrom it forms a cast bar 12 by means of a cooled ingot mold 13 . [0057] At the outlet of the ingot mold 13 , the cast bar 12 is cooled on one side by means of a cooling section 14 , while the heating elements 2 are situated in contact with one of the surfaces of the cast bar 12 . Its ideal arrangement is next to the outlet of the ingot mold 13 and along the section of the refrigeration 14 on its opposite side. [0058] The cast bar 12 can be cooled with water jets or spray, as it is conventional practice, although protecting from said cooling process the side where the heat is applied for the elimination of the interstitial elements (the heated peripheral region or hot spot). [0059] Table 1 contains some examples of the range of temperatures implied in the method of the present invention, for different alloys. [0060] It must be pointed out that the temperature whereat the peripheral regions of the mold have to be maintained have to be as high as possible from a practical point of view, but comfortably less than the melting point of the alloy. [0000] TABLE 1 Illustrative values, for different alloys, of the melting temperature, the temperature at which hot spots on the surface of the casting should be kept at and the critical core temperature. Hot spot Critical Alloy Melting point temperature temperature Low C steel 1750° C. 1000° C.-1700° C. 400° C. High C steel 1580° C. 1000° C.-1500° C. 400° C. Alloy steel 1700° C. 1000° C.-1600° C. 400° C. Cast iron 1400° C. 1000° C.-1350° C. 400° C. Copper 1350° C.  900° C.-1300° C. 400° C. Nickel alloys 1550° C.-1700° C. 1000° C.-1600° C. 400° C. [0061] Regarding the holding time necessary at each heated peripheral region or hot spot, this time at temperature depends on the volume and the geometry of the casting in question. Nevertheless, it must be stressed the importance that the heating elements produce the hot spots on the surface of the casting must be active from the moment when the mold is filled. These hot spots must also be held at the suitable temperature until the temperature of the core of the casting has decreased below a critical temperature (approximately 400° C.). [0062] Once the core reaches such said critical temperature, the power applied to the heating element can be slowly reduced, always guaranteeing that the hot spot is at a higher temperature than the core regions of the casting, until both are below the critical temperature. The time necessary to cool the core below the critical temperature can be estimated from some simple modelling of mold and casting cooling. [0063] Despite having referred to a specific embodiment of the invention, it is clear for a person skilled in the art that the method and the mold disclosed can undergo numerous variations and modifications, and that all of the mentioned details can be substituted for other technically equivalent details, without departure from the scope of protection defined by the attached claims. [0064] For example, possible modifications can be as follows: instead of using a temperature measurement system, the control system can be managed by other means (for example, simply by determining, via modelling or experimentally the holding time necessary for each hot spot(s) to produce the right effect and setting their heating time accordingly); the heat applied to the surface of the casting do not need to be continuous, but followed a suitable function, with varying intensity; the surface heating of the surface of the casting is maintained until the core temperature drops below 400° C.; the interstitial elements do not need only to be diffused to the region below the surface where the heating is being applied, but due to the proximity of such surface, a fraction of such interstitial elements could diffuse out of the metal (desorption) and, therefore, obtaining their elimination from the casting; and the heating elements could be implemented either integrated in the mold walls, or as removable attachments associated therewith.

The method for reducing interstitial elements in alloy castings which comprises the following steps: pouring the alloy for the formation of a casting; and allowing said alloy to cool. According to the method, at least a peripheral region of the casting is heated, so that the flux of interstitial elements is caused towards the at least one peripheral region. The method is achieved where most of the interstitial elements concentrate in at least one region in the surface region of the casting. At later stages these elements can be easily eliminated from the respective regions by means of a thermal surface treatment or surface machining of the casting.

BACKGROUND OF THE INVENTION [0001] The invention relates to a transmission coil which is configured to inductively transfer energy, comprising a carrier, a coil arrangement with a multiplicity of turns, and a capacitance which forms, together with the coil arrangement, an oscillatory circuit. Further aspects of the invention relate to a fixed charging station and to a vehicle, each comprising such a transmission coil, and to a system for inductively charging vehicles comprising a fixed charging station and a vehicle. [0002] Various systems for the contactless transfer of energy are known for conveniently charging electrical energy stores. Depending on the configuration, these systems can be used, for example, for charging consumer electronics such as, for example, cell phones or MP3 players or for charging electrically driven vehicles. Electrically driven vehicles comprise, for example, industrial trucks which are used for transporting goods in a warehouse, hybrid vehicles which have both an electric drive and an internal combustion engine, and purely electrically powered motor vehicles. [0003] DE 20 2011 077 709 A1 discloses an arrangement for transmitting electrical energy, in particular for charging an energy store of a mobile carrier, in particular of a motor vehicle. The arrangement comprises an electromagnetic transmission unit which is formed by two transmission elements which are embodied as coils. One of the coils is assigned here to the motor vehicle, and the other is assigned to a charging station. Each coil is assigned a capacitor, wherein in each case a capacitor with a coil forms a resonant circuit. Furthermore, the arrangement comprises rectifiers, power inverters and a PFC (Power Factor Correction) circuit. The PFC circuit permits, inter alia, reactive power to be compensated. Using the reactive power compensation, it is also possible to transmit the energy with a high level of efficiency even in the case of a relatively weak inductive coupling. [0004] A disadvantage of the prior art is that in addition to the transmission coils a multiplicity of separate components are also required. SUMMARY OF THE INVENTION [0005] A transmission coil is proposed which is configured to inductively transfer energy, comprising a carrier, a coil arrangement with a multiplicity of turns, and a capacitance. There is provision here that the capacitance is formed by a multiplicity of capacitors, wherein each capacitor is assigned to an individual turn or a group of at least two turns of the coil arrangement, and the capacitors are arranged, together with the coil arrangement, on the carrier. [0006] Transmission coils are required for the inductive transmission of electrical energy, wherein a primary transmission coil is arranged in a charging station, and a secondary transmission coil is assigned to a mobile energy store which is to be charged. In order to transmit energy, the primary coil is excited with an alternating voltage, as a result of which an alternating magnetic field is produced in the region of the primary transmission coil. If the secondary transmission coil is moved into the vicinity of the primary transmission coil, with the result that the magnetic field of the primary transmission coil flows through said secondary transmission coil, an electric current is induced in the secondary transmission coil. [0007] For an efficient transmission of energy, oscillatory circuits are formed from a coil arrangement with a multiplicity of turns and a capacitance. The oscillatory circuit is excited with an alternating voltage which is generated by power electronics. In this context, it has been customary hitherto that the power electronics and the capacitance which is necessary to form the oscillatory circuit are arranged spatially separate from the coil arrangement. In this context, the capacitance is usually formed by one or a small number of capacitors with a high capacitance and is assigned in its entirety to the coil arrangement. [0008] In contrast, in the case of the transmission coil according to the invention there is provision to use a multiplicity of capacitors instead of a single capacitance which is assigned to the entire coil arrangement, wherein each capacitor is assigned to an individual turn or to a group of at least two turns of the coil arrangement. In the case of turns which are combined to form groups, the coil arrangement comprises a multiplicity of such groups. In this context, each individual capacitor or each individual capacitance is, considered per se, respectively considerably smaller than the entire capacitance assigned to the coil arrangement. As a result, the installation space which is required for each individual capacitor of the capacitors also turns out to be significantly smaller, which permits the individual capacitors to be arranged jointly on a carrier, together with the coil arrangement. [0009] The carrier holds both the coil arrangement and the capacitors which are assigned to the individual turns or groups of turns and secures them mechanically. The carrier is preferably embodied as a metal plate whose external shape essentially follows the shape of the coil arrangement. A metal such as, for example, aluminum is preferably used as the material, wherein the turns of the coil arrangement are electrically insulated from the carrier. [0010] A group of turns usually comprises between 2 and 20 turns, and the entire coil arrangement usually comprises between 4 and 200, preferably between 10 and 100 turns. [0011] In a further embodiment of the invention, there is also provision that, furthermore, power electronics, which comprise a power inverter and/or a rectifier and/or further circuit components (e.g. microcontroller for controlling the charging sequence), are arranged on the carrier. [0012] In this embodiment, all of the components which are required for the transmission of energy are integrated together with the respective transmission coil to form one unit. If a transmission coil is embodied, for example, as a primary transmission coil, in particular a rectifier, a power inverter, the coil arrangement with the multiplicity of turns as well as the capacitors which are assigned to the individual turns or individual groups of turns are arranged on the carrier. [0013] If the transmission coil is embodied as a secondary transmission coil, for example a rectifier, the coil arrangement with the multiplicity of turns or groups or turns and the respective capacitors are arranged on the carrier. [0014] The transmission coil according to the invention requires no further external components for its operation. The primary transmission coil only then needs to be connected to a power supply system for the supply of energy. The secondary transmission coil then only needs to be connected to the electric energy store which is to be charged. [0015] In one variant of the transmission coil according to the invention, the power electronics are configured to deactivate or activate individual turns or individual groups of turns of the coil arrangement. [0016] Since each individual turn of the coil arrangement or each group of turns is assigned a separate capacitance in the form of a capacitor, each turn or group of turns constitutes, considered per se, an independent oscillatory circuit. This permits individual turns or groups of turns to be deactivated, and not included in the transmission of energy, without further compensating measures. This can be utilized, for example, to influence the shape of the magnetic field generated by the transmission coil or to produce various turn conditions. [0017] In one embodiment of the invention, the turns of the coil arrangement are arranged in the form of concentric circles or a spiral path on the carrier. A rectangular or square embodiment of the turns is also conceivable. In this context, the power electronics and/or the capacitors are preferably located in the center of the coil arrangement. Such an arrangement permits an extremely compact design of the transmission coil. [0018] In one embodiment of the invention, the carrier is configured to serve as a shield for the electromagnetic compatibility (EMC). [0019] In the power electronics, in particular in the case of a power inverter, alternating magnetic fields are produced which have to be shielded in order to avoid adversely affecting radio transmissions in the surroundings and the functioning of other electronic devices in the surroundings and in order to comply with legal requirements for the protection of persons against magnetic fields. An electrically conductive material is required for the shielding. If, for example, the carrier is configured in such a way that it surrounds the coil arrangement and the power electronics and the carrier is also fabricated from an electrically conductive material such as, for example, aluminum, the carrier can shield electromagnetic radiation which is produced. [0020] In a further embodiment of the transmission coil, the carrier is configured in such a way that it serves as a heat sink for the capacitors and/or for the power electronics. For this purpose, a material which has good thermal conductivity is preferably selected for the carrier. Therefore, in particular aluminum and copper are suitable as materials, wherein aluminum is more cost-effective than copper and is therefore preferred. [0021] In a further embodiment of the transmission coil there is provision that the carrier comprises ducts which are configured to have a cooling medium flowing through them. The cooling medium which is used can be, for example, a water-glycol mixture. Such an embodiment of the carrier is suitable, in particular, for conducting away the waste heat of the power electronics and of the capacitors. However excessive heating of the turns of the coil arrangement can also be avoided in this way. [0022] In one embodiment of the transmission coil, said coil comprises more than one coil arrangement. In particular, the transmission coil can comprise two coil arrangements. In this context, the two coil arrangements can be connected to one another in such a way that the turns are connected in the same direction or in opposite directions. [0023] A further aspect of the invention is making available a fixed charging station which is configured to charge vehicles in a wireless fashion, wherein the charging station comprises at least one or precisely one of the transmission coils described herein as a primary transmission coil. [0024] Furthermore, a vehicle is made available which is configured to charge in a wireless fashion, wherein the vehicle comprises at least one or precisely one of the transmission coils described herein as a secondary transmission coil. The vehicle represents a mobile unit which can interact with a charging station. [0025] Furthermore, a system is made available for inductively charging vehicles, which system is formed by a fixed charging station and a vehicle, wherein both the charging station and the vehicle comprise at least one or precisely one of the described transmission coils. In this context, in the system there is provision that the secondary transmission coil of the vehicle is moved temporarily into the vicinity of the primary transmission coil of the charging station, with the result that the magnetic field which is generated by the primary transmission coil flows through the secondary transmission coil. After the ending of the charging process, the vehicle can exit the charging station again, as a result of which the secondary transmission coil is removed from the region of the primary transmission coil. [0026] The transmission coil is not limited to the use in conjunction with the inductive charging of vehicles. Depending on the configuration of the transmission coil, said coil can be used, in particular, to charge any mobile units with an energy store. Examples of this are the wireless charging of cell phones or of electrically powered tools. In this context, a primary transmission coil is assigned to a charging unit, and a secondary transmission coil is assigned to the mobile unit. [0027] In the systems known from the prior art, the charging station and the mobile unit which interacts with the charging station comprise a multiplicity of separate discrete assemblies. In the case of the mobile unit which contains the secondary transmission coil, these are the coil arrangement, the capacitance, the rectifier and a radiator. In this context, every component must satisfy per se all the requirements made, for example, of the cooling or the shielding for the electromagnetic compatibility (EMC), as a result of which redundancies occur. These redundancies are avoided with the measures of the invention by means of a fully integrated design in which the transmission coil comprises, in addition to the coil arrangement, also the necessary capacitances and, if appropriate, the necessary power electronics, and in which the coil arrangement, the capacitance and, if appropriate, the necessary power electronics are arranged together on a carrier. This commonly used carrier equally satisfies the function of a mechanical carrier, of a shield and of a radiator for all the components which are accommodated. As a result, there is a saving in material without a restriction of the functionality, which reduces the required installation space, the weight and the costs of the transmission coil. [0028] In addition there is provision to use, instead of a single capacitance which is assigned to the entire coil arrangement, a plurality of capacitors which are each assigned to an individual turn of the coil arrangement or to a group of turns of the coil arrangement. In this context, each turn or each group of turns is compensated individually by the respectively assigned capacitor. This permits, when necessary, individual turns or groups of turns to be deactivated without the need to perform additional measures to adapt the oscillatory circuit. Such deactivation of individual turns or of individual groups of turns permits, for example, the magnetic field generated by the primary transmission coil to be changed and to be adapted in optimum way to the respectively used secondary transmission coil or different turn conditions to be produced. [0029] Furthermore, the compensation of individual turns or groups of turns provides the advantage that the maximum resonant voltages which occur can be significantly reduced. As a result, the expenditure on insulation and shielding can be lowered. [0030] In addition, the arrangement of all the relevant components of a transmission coil on a common carrier facilitates the cooling. Only the common carrier then has to be cooled, and this is possible, for example, with liquid cooling or with air cooling. Moreover, by integrating all the relevant components it is possible to achieve a saving in terms of additional components such as, for example, plugs, clamped connections or additional housings. BRIEF DESCRIPTION OF THE DRAWINGS [0031] In the figures: [0032] FIG. 1 shows a charging station with a primary transmission coil according to the prior art, [0033] FIG. 2 shows a transmission coil according to the invention in a sectional view from the side, and [0034] FIG. 3 shows a sectional illustration of a transmission coil according to the invention from above. [0035] In the following description of the figures, identical or similar components and elements are denoted by identical or similar reference symbols, wherein a repeated description of these components or elements will not be given in individual cases. The figures represent the subject matter of the invention only schematically. DETAILED DESCRIPTION [0036] FIG. 1 shows a charging station with a transmission coil according to the prior art in a schematic illustration in a cross section from the side. [0037] FIG. 1 illustrates a transmission coil 10 ′ which comprises a coil arrangement 11 ′ with a multiplicity of turns 12 ′. A ferrite element 14 ′, which serves as a ferromagnetic core of the coil arrangement 11 ′, is arranged around the turns 12 ′. The coil arrangement 11 ′ is provided with an electrically conductive shield (e.g. aluminum) 16 ′ in order to shield the magnetic stray field. [0038] In order to generate a magnetic field, the coil arrangement 11 ′ is connected to a switching cabinet 18 ′ via a connecting line 24 ′. The switching cabinet 18 ′ comprises power electronics 20 ′ and a capacitor 22 ′. The capacitor 22 ′ is connected to the coil arrangement 11 ′ via a further connecting line 26 ′, the power electronics 20 ′ and the connecting line 24 ′, wherein the coil arrangement 11 ′ and the capacitor 22 ′ together form an oscillatory circuit. [0039] If the transmission coil 10 ′ is embodied as a primary transmission coil, the oscillatory circuit is excited by means of the power electronics 20 ′, with the result that an alternating magnetic field is produced. This alternating magnetic field can be converted again into electrical current by a correspondingly equipped secondary transmission coil. If the transmission coil 10 ′ from FIG. 1 is embodied as a secondary transmission coil, the transmission coil 10 ′ is moved into the vicinity of a primary transmission coil, with the result that the alternating magnetic field of the primary transmission coil flows through the secondary transmission coil. Owing to induction in the secondary transmission coil, the oscillatory circuit is excited and the electrical energy can be extracted by means of correspondingly configured power electronics 20 ′, comprising a rectifier in this case. The electrical energy can then be used, for example, to charge an electrical energy store such as, for example, a battery or an accumulator. The electrical energy store can be assigned, in particular, to an electric vehicle or a hybrid vehicle. [0040] FIG. 2 illustrates a transmission coil 10 according to the invention in a sectional illustration from the side. [0041] The transmission coil 10 comprises a carrier 17 , which is fabricated, for example, from aluminum. A coil arrangement 11 , which comprises a multiplicity of turns 12 and a ferrite core 14 , is accommodated in the carrier 17 . The turns 12 of the coil arrangement 11 are wound around a central region 13 in a helical shape. In the central region 13 , the carrier 17 forms a trough in which integrated electronics 21 are arranged. The integrated electronics 21 comprise further, preferably all of the further, components which are necessary for operating the transmission coil 10 , in particular, for example, the power electronics and the resonant capacitance as described below with reference to FIG. 3 . The capacitance is divided here into a large number of individual capacitors which are each assigned to an individual turn 12 or a group of turns 12 . In this context, in each case a capacitor forms, together with a turn 12 or a group of turns 12 , an oscillatory circuit. [0042] FIG. 3 shows the transmission coil 10 according to the invention in a schematic view from above. [0043] FIG. 3 illustrates in transparent form the carrier 17 and the ferrite core 14 , so that the interior of the transmission coil 10 can be seen. As can be inferred from the illustration in FIG. 3 , the transmission coil 10 has a coil arrangement 11 which comprises a multiplicity of turns 12 . The illustration in FIG. 3 contains seven turns which are denoted by the reference numbers 101 , 102 , 103 , 104 , 105 , 106 and 107 . Each of the turns 12 is assigned here at least one capacitor 22 as a capacitance, wherein the capacitors are denoted by the reference numbers 121 , 122 , 123 , 124 , 125 , 126 and 127 . In each case a capacitor 22 is connected in series here with a turn 12 , with the result that an oscillatory circuit is formed. In this context, the first capacitor 121 is connected to the first turn 101 . In addition, the individual oscillatory circuits are connected one behind the other in series, with the result that the end of the first turn 101 which is not connected to the first capacitor 121 is connected to the second capacitor 122 . In this way, each turn 12 adjoins two capacitors 22 , wherein for this purpose an eighth capacitor 128 is additionally arranged at the end of the last and seventh turn. The connection to power electronics 20 is produced via the first capacitor 121 and the eighth capacitor 128 . [0044] The coil arrangement 11 can be excited by means of the power electronics 20 if the transmission coil 10 is embodied as a primary transmission coil, and an alternating magnetic field is therefore generated. Additional external components are unnecessary, and a connection to the electrical power supply system must merely be established via an electrical terminal 32 . [0045] If the transmission coil 10 is embodied as a secondary transmission coil and if it is introduced into the alternating magnetic field of a primary transmission coil, the coil arrangement 11 is excited by means of magnetic induction and an electric current can be extracted by means of the power electronics 20 . Said electric current can be made available via the electrical terminal 32 , in order, for example, to re-charge a mobile energy store. [0046] Both the power electronics 20 and the capacitors 22 can heat up during operation. In order to conduct away the heat, they are arranged on the carrier 17 , which also serves as a heat sink. If pure air cooling is not sufficient, it is possible, as outlined in FIG. 3 , to provide ducts 30 via which a cooling medium such as, for example, a water-glycol mixture can be fed in. The excess heat can be carried away by means of the cooling medium. [0047] In a further embodiment (not illustrated), each individual turn 12 is not assigned a capacitor 22 but rather a plurality of turns 12 , for example between two and ten turns 12 , are combined to form a group of turns 12 , wherein the entire group of turns 12 is assigned a capacitor 22 . [0048] In a further embodiment variant which is not illustrated in the figures, the oscillatory circuits, which are each formed from a turn 12 or a group of turns 12 and a capacitor 22 , are not connected in series with one another but rather each connected directly to the power electronics 20 . In such an embodiment, the power electronics 20 can actuate the individual turns 12 or individual groups of turns 12 separately. In this context, for example a single turn 12 or a group of turns 12 can be deactivated completely, or it would also be conceivable to excite the individual turns 12 or the oscillatory circuits, formed thereby, with different intensities. In this way, the alternating magnetic field which is generated by the coil arrangement 11 can be influenced selectively. This can be utilized to optimize the efficiency of the transmission of energy, in particular when the primary and secondary transmission coils which are used for transmitting energy are not embodied in an identical way or are not aligned with one another in an optimum way. [0049] In further variants of the transmission coil 10 it is possible to accommodate more than one coil arrangement 11 on a carrier 17 . In particular, two coil arrangements 11 can be arranged together on a carrier 17 . In this context it is possible to connect the coil arrangements 11 in such a way that the turns 12 of the respective coil arrangements 11 are connected in the same direction as one another or in opposite directions. [0050] The invention is not restricted to the exemplary embodiments described here or to the aspects emphasized herein. Instead, a multiplicity of modifications within the scope of the average ability of a person skilled in the art are possible within the range indicated by the claims.

The invention relates to a transmission coil ( 10 ) configured for inductive energy transfer, comprising a carrier ( 17 ), a coil arrangement ( 11 ) having a plurality of turns ( 12 ), and a capacitance. It is thereby provided that the capacitance is formed of a plurality of capacitors ( 22 ), wherein each capacitor ( 22 ) is assigned to an individual turn ( 12 ) or to a group of at least two turns ( 12 ) of the coil arrangement ( 11 ), and together with the coil arrangement, the capacitors ( 22 ) are arranged on the carrier ( 17 ). The invention further relates to a stationary charging station and to a vehicle, each comprising such a transmission coil ( 10 ), and to a system for the inductive charging of vehicles. No drawing text to be translated

CROSS REFERENCE TO RELATED APPLICATIONS The present application is a continuation-in-part of the earlier patent application Ser. No. 07/560,604 filed Jul. 31, 1990 now abandoned. THE FIELD OF THE INVENTION The present invention relates to a Gardening Information Kit to be used in supplying the amateur or the advanced gardener with all relevant information regarding dates, planting, transplanting, growing, watering, fertilizing, spraying, harvesting and storing a wide variety of plants and vegetables. BACKGROUND OF THE INVENTION The Gardening information Kit was created due to a need for information while in the garden without reading volumes of reference material or bringing these books into the garden. The home gardener grows many different plants and vegetables all with different protection, spacing and care needs. It is difficult if not impossible to commit all this information to memory. Therefore, the gardener will probably have to refer to his reference material. Some gardeners only have seed packets, some have an extensive library. Most of the seed packets do not provide the appropriate information needed for the many tasks to complete harvest. It is difficult to bring these reference books into the garden without some damage. After the gardener reads his reference material, how does he easily bring this information into the garden. Many questions go unanswered. When to plant is probably one of the most important questions that a gardener asks. Most gardeners try to push the season and plant as early as possible. If the gardener plants frost sensitive vegetables too early, destruction of the crop will be the result. He must know what to plant and when. A tool was needed that could give him the correct information about when to plant for any latitude in the country or internationally, be user friendly and at the same time provide a calendar. There has been a recent increase in public awareness of the health benefits of organic gardening, especially vegetable gardening (defined as gardening without the use of petro-chemically based herbicides, fungicides, pesticides, and fertilizers that have been associated with the causes of many health problems including cancer). The organic method biologically enhances the soil, avoids pollution and creates an environment which is healthy for the gardener and his family. The awareness level of protecting us from the use of dangerous pesticides has even reached the petro-chemical industry. Even Ortho, a subsidiary of Cheveron, now producing a line of organic products. It certainly means that there is a base of consumers who prefer the organic to the petro-chemical products. Many people subscribe to the use of organic gardening techniques in home vegetable gardening. However, many people who try home vegetable gardening, especially first timers, are not sufficiently experienced and have not been exposed to the methods that are actually simple. There is also a preconceived notion that organic gardening methods are difficult and result in poor quality produce. Most gardeners are not aware that there are easy alternatives to the petro-chemical industry's herbicides, fungicides and pesticides. In fact most garden pests can be managed by natural, barrier, botanical and biologically commercially available products. There have been many books written on the subject of gardening, but few on organic gardening as compared to the plethora of information available. Education is needed in order to change over to organic gardening. This can be a deterrent to practicing organic gardening. Some of the more important questions that concern gardeners are, ie.: which vegetables are prone to be killed by the frost, which can be planted for Fall harvest, or which need to be started indoors. The ability of this kit to sort the data cards without reading each individual card to answer these kinds of questions is invaluable. A kit was needed that could sort out specific questions and pieces of information. The summary of the above problems are as follows: how does one summarize and transfer the information with an organic orientation, how does one avoid bringing books into the garden, how does one manipulate planting dates for the gardener's specific locale, how does one sort information quickly and how does one minimize the waisting of time. The Gardening information Kit solves these problems with its two components. The kit combines 2 elements which serve different functions yet when combined together they create a complete source of information for every aspect of growing the target vegetable or plant including dates and the hows of germination, starting seedlings indoors, transplanting, planting, watering, spraying, harvesting and storage. 1. It summarizes information concerning each vegetable as completely and as clearly as possible, free from clutter and in a form which the gardener can use effortlessly. 2. It gives the home gardener the ability to have a user friendly sorting system similar to a data base at his fingertips right i the garden. In the present embodiment there are 44 specific pieces of information available, presented on the vertical sides, but not limited to, of a standard sized paper, for example. Categories for the storing stations are determined by the subject matter of the kit, ie. vegetables or perrenial flowers. 3. The circular calendar calculator gives the gardener the ability to manipulate specific dates for his specific locale and for specific vegetables and/or plants. It can be used to determine when to start seedlings, when to plant directly into the garden, when to transplant seedlings, when to discontinue planting, when is the expected harvest date, and to determine if there is enough time for another crop before Fall frost. This is all executed by gardeners anywhere in the country. The only piece of information that the gardener needs to provide are the dates of the first and last frost. 4. It addresses the principal aims of organic agriculture as adopted by the International Federation of Organic Agriculture Movements. U.S. Pat. No. 3,316,668, issued to Rogers on May 2, 1967, disclosed an adjustable garden chart which is a device for correlating information recorded on a plurality of indicia bearing strips. Although Rogers' design allows one to retrieve information regarding the growing of certain crops, He uses strips and reels which can be moved together or independently. His device could also be applied to finding the constellations int he various skies throughout the year. U.S. Pat. No. 4,248,458, issued to Brody on Feb. 3, 1981, is a device used in the field of horse racing. Its object is to randomly select the horses for Win, Place, Show, Daily Double, Quinella, Perfecta, and/or Trifecta without the seu of publications and authoritative sources. This device uses three concentric circles with indicia; however, it also contains a face plate with "equicircumferentially distributed presentation openings" for the above betting selections and also contains a bottom cover for a total of five wheels. The indicia which can be seen thru the face plate openings are only used after the three wheels have been arbitrarily moved by manipulating them on the reverse side. It is then that the bettor turns this device to the obverse side to reveal the numbers of the individual participants. The information indicia contained in the embodiment of the circular calendar calculator responds to the specific problem of planting dates (from the earliest planting date to discontinuation). Not only does this kit manipulate multiple indicia, but unlike Brody, it acts as an informational source. Six distinct items can be determined by the circular calendar calculator unlike Brody's which only reveal one, the numbers of participants matched with the type of betting possibilities. SUMMARY OF THE INVENTION It is an object of the present invention to provide a kit of gardening information which is user friendly in that it provides substantially all of the information necessary for the home gardener to successfully raise vegetables. It is a further object of the present invention to provide a kit having several components which the gardener can selectively use on site, in the garden, in any weather and the allows immediate access to all the information necessary, in a timely fashion, to accomplish those tasks necessary for the successful growth and harvest of crops and/or plants. It is still another object of the present invention to provide a Gardening Information Kit that contain several components which are useful both independently and in combination to successfully plan, plant, raise and harvest vegetables. The subject invention comprises a two component system, namely (1) data cards with information concerning growing information for a variety of vegetables, which data cards can be mechanically sorted according to particular categories of information contained on the face sorting card; (2) a circular calendar calculator wheel to determine specific information regarding optimum task execution dates throughout the calendar year. While it is contemplated that the gardening information kit will aid the organic gardener, the system can also be used for all types of gardening, i.e. vegetables, fruit and flower, whether or not organic methods are utilized. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will now be described, by way of example, with reference to the accompanying drawings in which: FIG. 1 is a plan view of the obverse of a data card of the present invention; FIG. 2 is a plan view of a calendar calculator wheel of the present invention; FIGS. 3-5 are elevational views of the outter, middle and inner discs forming the calendar calculator wheel of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The present invention is a Gardening Information Kit designed to readily provide the novice or advanced gardener with all relevant information needed to plan, plant, grow, maintain, harvest and store a wide variety of plants and vegetables. It would be here noted that the terms "plans" and "vegetables" are being used in a generic sense and would include all the things an average homeowner might want to grow on his property, such as herbs, flowers, shrubs, trees and ornamental plants, as well as plants and vegetables normally growth for human consumption. It should also be noted that the words "major category" are assigned the meaning of the grouplings of indicia in the main body of the data card and that the words "sorting category" are assigned the meaning of information that can be retrieved by inserting the sorting tool into the stations of holes 22 and slots 20. The subject kit has two primary components, namely (1) a plurality of data cards, as shown in FIG. 1; (2) at least one calendar calculator wheel, as shown in FIG. 2; Turning first to the data cards 10 of FIG. 1, the data card is preferably of sufficient size to hold a lot of data, for example 8.5×11" or conventional letter size. The data is preferable a laminate formed by plastic coatings on both sides of a printed sheet of paper or printed on plastic laminate similar to a credit card. This provides a certain amount of rigidity and durability for the data card which is necessary for the task of repeated sorting. Information is provided on both the obverse and reverse of each data card according to several major categories of information, such as but not limited to "Temperatures and Germination", "Dates", "Apperance", "Planting and Transplanting Procedures", "Planting Methods", "Thinning", "Soil", etc. as illustrated on the obverse in FIG. 1. There may be as many as 18 or more major categories or groupings of informational indicia depending on need. Each data card 10 contains information specific to the plant or vegetable that is described and/or illustrated on the top of the data card, Tomatoes in the illustrated example. In order to manually sort the data cards 10 by any one of a number of sorting categories, each data card is provided with sorting means 18 formed by a plurality of holes 22 and slots 20 arrayed along at least one marginal edge 24 of each data card. Besides being able to sort the various families or groups of vegetables, this system allows for selecting, ie: "All cool weather vegetables", "Seedlings started indoors", "Vegetables that tolerate shade", "Vegetables that are heavy feeders", or "Vegetables that are attacked by the squash vine borer", etc. Many other sorting categories may be included or substituted. The patterning of holes and slots is unique for each data card but the positioning stations of all holes and slots on all cards is identical. All positions or stations will be numbered and a face card with the numbered indicia will be provided. Thus, to select any particular piece of sortable information or specific group of data cards, one looks up the corresponding number, inserts an elongated blunt instrument, such as a needle or rod (not shown) into the selected numbered position and passes the sorting tool through the aligned holes 22 and slots 20 of the data cards 10 making up the stack. It is assumed that the desired edge 24 is in the top most position. The needle or rod is then moved vertically out of the stack to pass out of the slots of those data cards which are not in the selected sorting category while carrying along the data cards having holes, as opposed to slots, at the selected position or station. For example, if someone desired all vegetables that need to be started indoors, they would first check to make sure that all the data cards 10 were facing in the same direction, look up the correct number on the face card, then they would insert an instrument, such as the above mentioned elongated blunt needle, into the select numbered position of a stack of data cards. The remaining data cards which do not apply to the selection are left behind in the stack until needed. When it comes time to return the data cards to the stack, it is not necessary to locate their original position in the stack or reinsert the data cards in any particular order. The used data cards can simply be placed, facing the same direction, in any order in the stack as the sorting system of the present invention allows them to be recovered any time form any order. This unique sorting system of the present invention allows access to a large quantity of information which has been presorted, while being easy to manipulate since the order of the data cards is not a factor in recovering the desired data cards. The above identified categories are only illustrative of the major and/or sorting categories contemplated by this invention. Many other categories could be included or substituted. FIG. 2 illustrates a circular calendar calculator wheel 12. The wheel 12 is preferably made of at least semi-rigid plastic or plastic coated material with a water-proof surface bearing the calendar informational indicia. Preferably the wheel 12 is of such a size to be able to contain information to be easily read, however, small enough so as not to make the calculator cumbersome to handle. Preferably, the outside dimension of the wheel 12 will be less than 81/2". The outter edge of the middle wheel 28 will be of such dimension as not to hide the indicia of the outer wheel 26 and some of the radiating spokes This allows the user of this tool to align the radiating spokes of the various wheels. The outter dimension of the inner wheel 30 should be less that the inside dimension of the most inner set of numbers 34, 36 of the middle wheel 28. This calculator wheel 12 consists of three concentric and coaxially rotatable mounted circular calculator discs; (1) the outside disc 26; (2) the middle disc 28; and (3) the inner disc 30 all relatively rotatable secured together by hub 32. It is contemplated that there could be a calculator wheel for each general family or grouping of vegetable or plants. The outside disc 26 FIG. 5 carries notations relating to the calendar year. It is preferably broken down into fifty-two accurate and equal portions which are in 7 day increments. The indicia which correlates to these lines will follow the calendar year, starting on January 1 and continues as follows: January 8, 15, 22, 29, February 5, 12, 19, 26, etc. The middle disc 28 FIG. 4 carries several sets of numbers in two concentric configurations for ease of calculation. The inner set of numbers 34 and 36 substantially completely encircling the middle disc 28 and spaced inwardly from its parameter. Each arcuate set of numbers 34 and 36 are designated plus (+) and Minus (-) numbers going clockwise and counterclockwise, respectively, from two nearly opposite zero points. These sets of numbers represent weeks before (-) and after (+) the Spring 40 and Fall 38 frost dates. Additional outer number sets 42 and 44 help in determining the number of days to a particular desired event, ie. days to harvest or the number of frost free days until the Fall frost. This is accomplished by selecting either the list 42 or 44 and then placing that zero of the selected list on the starting date which is found on the outter disc 26. Both of these sets of numbers are located on the outer perimeter of disc 28. The number set 42 ranges from 0 weeks to 16 weeks (ie. 0 1, 2, 3, . . . 16). The number set 44 ranges from 0 days to 126 days in 7 day increments (ie. 0, 7, 14, 21 . . . 126). Each number for both sets 42, 44 corresponds to the spokes of the wheel. Also in the middle wheel 28 around the hub 32 occurs the name of the grouping or family 46 that is contained on this individual wheel. Concentrically radiating inward from 34 and 36 are the names of the individual vegetables 48 contained on this individual wheel. Directly next to the names of the vegetables are numbers 50 which indicate either the number of days from transplant to harvest or the number of days from direct seeding to harvest. To the right and in line are shaded areas 52 which indicate the range of time when the vegetable may first be placed in the ground either as a seed or transplant and the end of this shaded area to the extreme right indicates the number of weeks to cease planting after the Spring frost or the number of weeks to cease planting before the first Fall frost. These areas will be shaded different colors or marked in some way as to indicate the difference between direct planting and those vegetables that may be stared as seedlings outside the garden, ie. in a greenhouse. It is in the latter case that the inner wheel 30 will be used. In the preferred embodiment the inner wheel 30 FIG. 3 is made of transparent material with sufficient thickness as to be able to withstand multiple manipulations. Fifty - two lines radiate from the hub 32 as was mentioned above. One of the lines will appear thicker than the others and will labeled the Transplant Date 54 and marked with zero. Moving to the left each line will be numbered 56 starting with 1 and continue, for example to ten. These numbers which correspond to time units (weeks) will be used in conjunction with the shaded areas 52 of the middle circle 28. Hatched areas 58 on the transparent inner circle 30 will indicate the number of weeks before transplant that the gardener is to start his seedlings indoors (ie. for Tomatoes it's 6-8 weeks before transplant). Vegetables that are only to be planted outside will not have a hatched area 58 on the transparent inner circle 30 directly over the corresponding vegetable 48. The following is a description of how to determine the date for starting, seedlings, when to transplant and when to expect the beginning of the harvest ie. Tomatoes. It is assumed that the last killing frost will occur before April 30th. The gardener wants to place out the seedlings as early as possible without the danger of frost. 1. Place the Spring 40 zero under the date April 30th, aligning the spokes of the wheels 26 and 28. 2. Align the Transplant Date line 54 of the inner wheel 30 with the extreme left edge of the shaded area 52 on the middle wheel 28. This is the earliest this gardener can plant safely for this area. 3. Look for the vegetable name 48 (Tomato) and follow the radius around to the left until the hatched area 58 of the inner circle 30. 4. Note that the hatched area 58 falls between the numbers of six and eight 56 on the inner circle 30. Continue following these radiating lines up to the dates of the outter circle 26. Seedlings may be started indoors between the dates of March 5th and March 19th when transplanted on April 30th and will be six to eight weeks old. 5. The name of the vegetable 48 Tomato has the number seventy-four 50. This number indicates the average number of days from transplant to harvest. 6. Align the zero 44 of the middle circle 28 to the date April 30th, the transplanting date. The number seventy-four falls between the numbers seventy and seventy-seven 44 printed of 28. The expected start of the tomato harvest is approximately July 13. In use the wheel is designed to instantly yield the following information 1. The date (or dates) on which one should start seedlings based on the last frost date. 2. The date (or dates) on which one should transplant the seedlings. 3. The date (or dates) on which one should plant directly in the garden. 4. The average number of days from seed to harvest or from transplant to harvest. 5. The approximate dates one should harvest the vegetables. 6. The possibility of succession planting may be determined by calculating the approximate number of frost free days between the harvest of the first crop and the harvest of the second crop. It is contemplated that, in use, the device of the present invention will provide the gardener will accurate information, easily readable, and in a format that will be rewarding to his efforts. Since information derived from this calendar calculator wheel is based on local frost dates which are supplied by the gardener, the wheel is substantially universal in application without regard to the planting zone. While there has been described what are at present considered to be the preferred embodiments of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention and it is therefore aimed too cover all such changes and modifications so as to fall within the true spirit and scope of the invention.

A Garden information Kit has two elements which provide all the information necessary for successful planting, growing and harvesting of crops. The first element is a set of data cards both carrying information and having means to easily sort the cards carrying the desired information. The second element is a calendar calculation wheel used to determine when certain events are to be executed.

RELATED APPLICATIONS [0001] This application claims priority from U.S. provisional patent application No. 60/519,227, which was invented by the same inventor, was filed on Nov. 12, 2003, and was entitled “Wheel Illumination Device”. FIELD OF THE INVENTION [0002] The invention relates generally to motor vehicle accessories. More particularly, it relates to lights and sound systems for motor vehicles. Even more particularly, it relates to systems for lighting motor vehicle wheels. BACKGROUND OF THE INVENTION [0003] Lighting systems for automobiles have been known ever since automobiles were first invented. The first lighting systems consisted of kerosene lamps with clear or colored lenses mounted at various places on the body of the automobile to provide notice to others that the automobile was approaching, and to illuminate the automobile's surroundings. A major drawback to this system was the need to continuously recharge the lamps by filling them with oil, and trim the wicks. Further, the lamps put out a limited amount of light. Even further, unless adjusted carefully, they sooted up their reflectors. [0004] Later, gas lighting systems were provided including lamps with integral to settling gas generators often called “carbide lamps”. Carbide lamps provide an intense light that is particularly suited for illuminating the road around the automobile. While it solved the problem of wick replacement, light intensity, and wick trimming, it still required each lamp to be separately filled and cleaned regularly. [0005] As the systems further developed, centralized gas systems were devised in which a large central gas generator provided gas to several lamps disposed about the periphery of the vehicle. This problem reduce the need for maintaining each one of several different lamps, replacing it with a single, central problem of filling, emptying, and cleaning the central gas generator. Carbide gas generators produce a noxious mix of corrosive chemicals and sludge that cannot be disposed of easily [0006] By the 1910's, battery-powered electrical lighting systems have been developed to replace the centralized gas arrangements. In these battery-powered systems, a battery disposed in the central location provided electrical energy to several lights mounted on the body of the vehicle. Wires extending from the battery were coupled to light bulbs that, in turn, illuminated the road in the surroundings of the vehicle. This solved the problem of periodic lamp cleaning, but replaced it with the problems of battery charging and battery maintenance. The batteries needed to be periodically charged. To do this, they must be either removed from the vehicle and taken to a charging station or the charging equipment must be brought to the battery in the vehicle. Either way, the lights require regular, even daily, adjustments and maintenance. [0007] Not long after this, generators were provided on automobiles to charge the batteries used for lighting. These generators operated whenever the vehicles were running, charging the batteries to maintain a supply of electricity. This battery/generator arrangement is the most common form of present-day automotive lighting. Light elements, which include incandescent light bulbs as well as LEDs, are fixed to the body of the vehicle at various locations. Wires are coupled to these lighting elements to provide them with power. The power is provided by an alternator driven by the engine, which in turn is coupled to a battery. The battery acts as a reservoir of the electrical energy when the engine is stopped. [0008] In addition to the centralized vehicle lighting systems, certain peripheral systems have been devised to provide extra lighting. For example, the automotive aftermarket product industry offers portable lights that plug into cigarette lighter outlets (more recently called “power outlets” since cigarettes have fallen on disfavor). These aftermarket lights can be fixed to a stalk supported by the outlet, or they can be disposed at the end of a flexible power cord that is plugged into the outlet. With these arrangements, the operator supports the light with his hand at the end of the power cord, which permits him to manipulate it and will, either inside or outside the operator's compartment. [0009] Lights have been fixed to the interior of automobiles to light up upon the occurrence of various events, such as the unlocking of an automobile by remote control or other manipulation of remote control buttons, the opening of the door, or the opening of the trunk (boot) or hood (bonnet). Of course, it has been common to turn automotive lights on and off with electrical switches virtually since they were first used in automobiles. [0010] Other automotive lighting systems have been triggered by optical sensors to turn on whenever the automobile (or rather, the optical sensor) is in darkness. These sensor arrangements are used with running lights (taillights and headlights) to ensure that the operator never drives the vehicle in the dark. Running lights serve two purposes: to illuminate the road for the operator's benefit, and to indicate to drivers ahead of the lighted automobile on the road and drivers behind the lighted automobile on the road of the automobile's presence. [0011] Novelty lighting systems are a more recent development. Novelty lighting systems can be understood generally as lighting systems intended to enhance the beauty are stylishness of the automobile, and are not intended as safety measures or basic operational features. Running lights and courtesy or interior lights are not novelty lights. [0012] Running lights, which include taillights, headlights, turn signals, parking lights, and reverse lights, are intended to enhance the safe operation of the vehicle over the road by indicating the presence of the automobile and its intentions to other automobile operators on the road. They are not “novelty lights”, although they may have novelty aspects such as special colors. [0013] Courtesy or interior lights, which include dome lights, side lights, dashboard lights, console lights, indicator lights, map lights, and instrument lights, are not intended for operators of other vehicles, but for the operators and passengers of the vehicle itself, to permit them to enter and exit the vehicle safely, and to operate the various controls within the vehicle with ease, comfort and speed. They also are not novelty lights. [0014] Novelty lights fall in the class of lights that are not necessary or required for safe operation of the vehicle or for the operator and passenger's ease and comfort, but for the personal satisfaction of the operator. Indeed, novelty lights, if viewable from outside the car, may be specifically banned in certain jurisdictions as interfering with vehicle running lights. Add-on or aftermarket lights may only be permissible to the extent they imitate already-permissible running lights. For example, large, high output, beamed white lights can only be used on the front of automobiles, and only if they are pointed in the same direction as the automobiles and headlights. In this sense, these aftermarket lights are not “novelty” lights, but supplements to (or replacements for) headlights. [0015] Novelty lights are not the only customizable feature of an automobile. Wheels and wheel trim have been another area of novelty customization. Automobile wheels were originally imitations of wagon wheels, having a wooden hub, with wooden spokes that extended outward to a wooden rim with metal binding. As time passed, the hub was replaced with a steel hub and the individual wooden spokes were replaced with metal spokes. By the 1920's, the entire wheel was made out of stamped or pressed metal. [0016] Not long after this, the enthusiasm for customizing automobiles expanded to include customizing wheels. Hubcaps were devised that provided a shiny or sparkling appearance to what was otherwise plain painted metal. Hub caps originally covered just the hub of the wheel. As time passed, and wheels became solid pressed or stamped metal structures, hubcaps extended all the way across the wheel from one side of the rim to the other. [0017] Until recently, hubcaps were fixed to the wheel itself. Either attached to the rim, or attached to the hub, they are fixed to the wheel and rotated at exactly the same speed as the wheel. These devices had no moving parts. They achieved their eye-catching effects merely by the many reflections of ambient light off their numerous faceted reflective surfaces. Recently, however, caps have been designed to sparkle even when the vehicle is stopped by mounting them on the wheel (or wheel hub) with bearings. In normal operation, as the automobile travels down the road, the hubcap is gradually accelerated to the rotational speed of the wheel. Although it is bearing mounted, and thus can spend relatively freely with respect to the wheel, the close coupling between the wheel and the hubcap causes air currents and a certain amount of mechanical drag to accelerate the hubcap. The particular advantage to this arrangement is what happens when the car is stopped. When the operator breaks the vehicle, the wheels slow down. The hubcaps, however, keep spinning even after the vehicle is stopped (for example at a stoplight). Only gradually do the frictional drag of the surrounding air and the slight residual drag of the bearing supporting the hubcap on the wheel cause the hubcap to slow down. During this deceleration, the hubcap (which typically has many bright reflective faceted surfaces), sparkles and appears to an outside observer viewing the automobile from the side as a multiplicity of bright twinkling lights. [0018] This arrangement, however, is limited. First, the hubcap only sparkles and twinkles with light when it rotates. When it is stopped, it no longer attracts the eye of the observer. Second, the speed at which the light reflected from the hubcap twinkles and sparkles is uncontrolled. It is strictly a function of the speed at which the hubcap turns, which depends upon the maximum speed of the car before deceleration, the speed of deceleration, and the friction between the hubcap and the wheel. None of these can be controlled with any accuracy. Third, the hubcap only sparkles and twinkles with light when an external light source is shined upon it. Without street lights, lights from surrounding buildings, or lighted signage, the spinning hubcaps are virtually invisible. [0019] What is needed, therefore, is an improved lighting system for automobile wheels. What is also needed is a wheel illuminating system. What is also needed is a means for lighting the wheels as they rotate. What is also needed is a means of providing the wheels with rotating lights. It is an object of this invention to provide such a system. [0020] These and other objects of the invention will become dear upon reading the description and examining the drawings below in which like-numbered items in all the drawings and the description represent the same elements, features, devices, structures, processes, or methods in all the other drawings and description. SUMMARY OF THE INVENTION [0021] In accordance with a first aspect of the invention, a system for illuminating an automobile wheel assembly of an automobile is provided, the wheel assembly including a hub, a wheel, and a tire, the system including a mount configured to be fixed to the wheel assembly, a plurality of lights fixed to the mount, a control circuit coupled to the plurality of lights to regulate the flow of electricity to the plurality of lights, and a power source coupled to the control circuit to provide said control circuit with electrical power for the lights, wherein the power source includes an electrical energy generating element as well as an electrical energy storing element. [0022] The control circuit may be a switch. The control circuit may be configured to automatically turn the plurality of lights on and off. The control circuit can be configured to store light patterns. The control circuit can be configured to change light patterns automatically. The control circuit can further comprise a remote-control receiver configured to receive remote-control signals. The control circuit can be responsive to remote-control signals indicative of a pattern of light illumination. The control circuit can be configured to change the colors of the lights. The control circuit can be configured to turn the lights on and off. The control circuit can be configured to change the rate at which the lights are turned on and off. The control circuit can be responsive to automatically turn off the lights. The control circuit can be configured to energize the lights when the wheel assembly is stationary. The control circuit can be configured to change the intensity of the plurality of lights in synchrony with an audio source. The audio source may be a sound system disposed in the automobile. [0023] The electrical energy generating element may be a generator. The generator may have a generator rotor and a generator stator. The generator rotor may be coupled to the wheel assembly to rotate with the wheel assembly when the automobile is driven over the ground. The generator stator may remain stationary as the automobile is driven or rotate at varying rates as long as the rate of rotation is less than the rate of rotation of the generator. The generator may be coupled to the automobile wheel assembly to rotate and generate electricity when the automobile is driven. The generator may be coupled to the automobile wheel assembly to not rotate and not generate electricity when the automobile is stopped. The electrical energy generating element may include a solar panel for direct conversion of light to electrical energy. [0024] The plurality of lights may include LEDs, incandescent lights, fluorescent lights, neon, electroluminescent panels, and ultraviolet lights. Each of the plurality of lights may have a color different from others of the plurality of lights. The lights may be mounted in light mounts, such as swivels, flexible goosenecks, tubes, or extension tubes. [0025] The lights may be coupled to a housing and face outward. The housing may support the light mounts in which the lights are mounted. The lights may be pointed to the wheel assembly to reflect light off the wheel assembly toward an observer. The lights may be coupled to a wheel of the wheel assembly. The lights may be coupled to a hole formed in the wheel. The lights may be stuck to the wheel. [0026] The mount may include a housing. The housing may enclose the lights. The housing may enclose the control circuit. The housing may enclose the power source. The housing may include a cap removably fixed to a cylindrical unit base or a unit base which corresponds to the configuration of the cap. The cap may be screwed to the unit base. The cap may be configured as a spinner. The spinner may have three points, or be a three-point star. The spinner may have four points or be a four-point star. The solar panel may be fixed to an outer surface of the housing. [0027] The system for illuminating a wheel assembly may further include a remote control configured to communicate with the control circuit. The remote control may be a wireless remote control. The remote control may be configured to activate the lights. The remote control may be configured to control the lights. [0028] The mount may include a lower section fixed to the wheel assembly to rotate with the wheel assembly; an upper section enclosing the control circuit and the power source; and a bearing disposed between the lower section and the upper section to permit relative rotation between the lower section and the upper section. The upper section may include a unit base; and a cover; wherein the unit base and the cover are coupled together to define an internal cavity configured to receive and support the control circuit and the power source. The plurality of lights may be coupled to holes formed in the unit base. The plurality of lights may be coupled to the unit base and are directed toward the wheel. The plurality of lights may be selected from the group consisting of LEDs, incandescent, electroluminescent panels, neon, fluorescent lights, and ultraviolet lights. The electrical energy generating element may include a generator, and further wherein said generator may be coupled to said lower section to be driven thereby. The generator may be coupled to and charges the electrical energy storing element. [0029] In accordance with a second aspect of the invention, a system for illuminating an automobile wheel assembly of an automobile is provided, wherein the wheel assembly includes a wheel and a tire, the system including: a plurality of lights configured to be supported on the wheel, a control circuit configured to be supported on the wheel, wherein the circuit is coupled to the plurality of lights and regulates a flow of electricity to the plurality of lights; and a power source configured to be supported on the wheel, wherein the power source is coupled to the control circuit to provide said control circuit and said plurality of lights with electrical power. [0030] The control circuit may include a receiver responsive to a wireless remote control. The receiver may control the operation of the plurality of lights in response to signals received from the wireless remote control. The control circuit may control the plurality of lights to emit light in a plurality of light patterns, and further wherein the control circuit is responsive to the remote control to change the light patterns. The plurality of lights may be capable of emitting light when the wheel is not rotating and when the wheel is rotating. The system may further include a mounting plate having a plurality of holes that are configured to engage lug nuts securing the wheel to the automobile, wherein the plurality of lights, control circuit, and power source are supported by the mounting plate. The system may further include an enclosure supported by the mounting plate, wherein the plurality of lights, control circuit, and power source are supported within the enclosure. The wheel assembly may further include a hubcap, and further wherein the plurality of lights, control circuit, and power source are configured to be supported by the hubcap. The system may further include a mounting plate configured to be fixed to the hubcap, wherein the plurality of lights, control circuit, and power source are configured to be supported by the mounting plate. The system may further include the wireless remote control, which is configured to communicate with the receiver to control electrical power sent to the plurality of lights. The control circuit and plurality of lights may be configured to emit at least one pattern of light, and further wherein said wireless remote control is configured to change said at least one pattern of light. The control circuit may be configured to change an intensity of the plurality of lights in response to an audio signal received by the receiver. The control circuit may be configured to change a rate at which the plurality of lights go on and off in response to signals received by the receiver. BRIEF DESCRIPTION OF THE DRAWINGS [0031] FIG. 1 is a perspective view of an automobile having a wheel assembly with a wheel illumination device in accordance with the present invention attached thereto. [0032] FIG. 2 is an exploded view of the wheel illumination device of FIG. 1 . [0033] FIG. 3 is an end view of the lower section of the wheel illumination device of FIG. 2 . [0034] FIGS. 4-5 are opposing end views of the unit base of the upper section of the wheel illumination device of FIGS. 1-3 showing the electronics box, rechargeable batteries, and lights installed inside the unit base. [0035] FIGS. 6-9 are perspective views of four alternative covers for the upper section of wheel illumination device of FIGS. 1-3 . [0036] FIGS. 10-13 are perspective side views of alternative light mounts for the wheel illumination device of FIGS. 1-5 . [0037] FIGS. 14-15 are cross-sectional side and end views of the unit base of the wheel illumination system with the electronics box, rechargeable batteries, lights, and wiring removed to better show a generator. [0038] FIG. 16 is a partial cross sectional view of the wheel assembly and wheel illumination device of the foregoing figures, wherein the wheel illumination device is coupled directly to a hubcap. [0039] FIG. 17 is a plan view of a universal attachment plate for coupling the base of the wheel illumination device to a wheel. [0040] FIG. 18 is a partial cross sectional view of the wheel illumination device of the foregoing FIGURES coupled to the universal attachment plate of FIG. 17 , which is in turn coupled to lug nuts of the wheel assembly. [0041] FIG. 19 is a partial cross sectional view of the wheel illumination device of the foregoing FIGURES, coupled to a hub cover, which is in turn coupled to the universal attachment plate of FIG. 17 , which is in turn coupled to lug nuts of the wheel assembly. [0042] FIG. 20 is a schematic representation of the control circuit of the wheel illumination device, including the circuitry in the electronics box, the battery and the generator. [0043] FIG. 21 is a schematic representation of an in-car remote control system configured to communicate with and program the control circuit of the wheel illumination device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0044] FIG. 1 is a perspective view of an automobile 98 having a wheel assembly 114 , the wheel assembly having a wheel illumination device 100 attached thereto. Wheel illumination device 100 includes a housing 102 further comprising a cylindrical unit base 104 that is enclosed with a cover 106 . Several fasteners 108 extend through holes in cover 106 and are threadedly engaged with matching or corresponding holes (not shown) in base 104 . Lights 110 extend through apertures in the back of the wheel illumination device 100 , extending around the edges of the wheel illumination device where they are directed toward the wheel itself. Lights 110 are controlled by control circuitry (not shown) inside housing or enclosure 102 . A solar panel 112 is fixed to cover 106 to receive solar radiation and power the lights. Other power sources, discussed below, may also be used in place off, or in addition to solar panel 112 . [0045] Housing 102 is fixed to universal mounting plate 300 , which is, in turn, fixed to lug nuts on the wheel. This mounting arrangement is shown in more detail in FIG. 18 . [0046] Wheel assembly 114 includes a wheel 116 and a tire 118 mounted thereon. Wheel assembly 114 also includes a wheel hub (see e.g. the wheel of FIG. 19 ). [0047] The wheel 116 of the automobile 98 is a front wheel that is steerable with respect to the rest of automobile 98 . Although wheel 116 is illustrated as a front wheel, it may also be a rear wheel. Automobile 98 has a wheel illumination device 100 fixed to each of the four wheels. [0048] In FIG. 1 , the additional unused holes and slots in plate 300 have been removed for ease of illustration. It should be understood, however, that the plate 300 in FIG. 1 is the same plate 300 shown in FIGS. 17, 18 , and 19 . [0049] FIG. 2 is an exploded view of the wheel illumination device 100 of FIG. 1 with lights 110 and fasteners 108 removed. The wheel illumination device includes a lower section 200 and an upper section 202 . Lower section 200 includes a base 204 and a shaft 206 . Upper section 202 comprises housing 102 , which includes a unit base 104 that is enclosed by a cap or cover 106 . Upper section 202 supports lights 110 , and electronics box 214 , and rechargeable batteries 216 . A solar panel 112 is affixed to the outside of cap or cover 106 . [0050] Lower section 200 is provided to couple the remainder of the illumination device to the wheel assembly 114 . It has a base 204 for attaching the illumination device 100 to the wheel assembly 114 from which shaft 206 extends. [0051] Referring now to FIGS. 2-3 , base 204 is preferably a planar and circular disk; however, it is not limited to this configuration. It has several features that enable it to be easily coupled to the wheel assembly. These features include several narrow slots or cuts 220 that extend radially from the periphery of the base inward toward the center of the base. Several slots 220 (preferably three or four) are preferably provided in base 204 . They are preferably spaced equidistantly around the periphery of the base. In addition to slots 220 , base 204 has a series of holes 222 , preferably three or four (as shown here), that are positioned equidistant from the periphery of base 204 and preferably in a symmetrical pattern. Base 204 also has a central hole 224 that, like slots 220 and holes 222 , extends completely through the base. Base 204 is preferably made of a lightweight metal or metal alloy. It may also be formed of a polymer or plastic that may be fiber reinforced, such as by carbon fibers. Other lightweight and durable materials may also be used. Base 204 is preferably between 1½ and 5 inches across. [0052] Shaft 206 is fixed (preferably welded or swaged) to base 204 . It is coupled to and between base 204 and unit base 104 of upper section 202 . Shaft 206 is hollow and cylindrical defining a central aperture 226 that extends the length of the shaft. Shaft 206 is coupled to base 204 such that a continuous passageway is formed that extends completely through central hole 224 and aperture 226 of shaft 206 , extending completely through base 204 and shaft 206 . Shaft 206 is preferably mounted perpendicular to base 204 and fixed to the center of base 204 . It is preferably constructed of lightweight metal or metal alloy, but may also be formed of a plastic or polymer that may be reinforced, such as by carbon fiber. Other lightweight and durable materials may also be used. [0053] Upper section 202 of wheel illumination device 100 includes a unit base 104 and a cap or cover 106 that encloses the unit base defining a hollow cavity. Upper section 202 also includes lights 110 ( FIGS. 1, 16 , 18 - 19 ), electronics box 214 ( FIG. 5 ), and rechargeable batteries 216 ( FIG. 5 ). The lights, electronics box and rechargeable batteries or disposed inside the hollow cavity formed by unit base 104 and cap or cover 106 . Upper section 202 also includes solar panel 112 that is fixed to the outside of cap or cover 106 . [0054] Referring to FIGS. 2, 4 and 5 , unit base 104 has a planar bottom 228 coupled to a cylindrical wall 230 . Bottom 228 has a central hole 232 . Unit base 104 is coupled to shaft 206 by inserting a shaft 206 through central hole 232 and tightening jam nuts 233 on either side of bottom 228 . When unit base 104 is fixed to shaft 206 in this manner, bottom 228 is parallel to base 104 and perpendicular to shaft 206 . To assemble unit base 104 to shaft 206 , the operator first places a jam nut 233 on shaft 206 . The operator then inserts the free end of shaft 206 into and through central hole 232 . The operator then threads a second jam nut 233 on to the free end of shaft 206 , and tightens the jam nuts together. [0055] Retaining rings are preferably used in place of jam nuts 233 if shaft 206 is not threaded. Unit base 104 can be positioned either closer to or farther from base 204 (coupled to the wheel) by adjusting the relative position of jam nuts 233 . This is particularly valuable when adjusting the wheel illumination device 100 to an optimum position that will most pleasingly illuminate the wheel. [0056] Bottom 228 has several holes 234 that extend completely through bottom 228 . These holes provide electrical access to a series of illumination systems, such as lights 110 . There are preferably at least four holes 234 distributed equally about the periphery of bottom 228 and adjacent an outer edge of bottom 228 . Each of holes 234 supports at least one associated light 110 . These lights are preferably LEDs, although other illumination sources may be used. Bottom 228 is preferably larger than the diameter of base 204 . [0057] Unit base 104 is supported on the end of shaft 206 . In the preferred embodiment, it is free to rotate with respect to shaft 206 , and preferably to stay stationary as the automobile 98 travels down the road and the wheel (and shaft 206 fixed to the wheel) rotates. This free rotation of unit base 104 is provided by bearing 236 , which is fixed to bottom 228 and defines central hole 232 . When shaft 206 is fixed to bottom 228 , with jam nuts, it is fixed to bearing 236 . Bearing 236 , in turn, is fixed to bottom 228 . Bearing 236 is preferably a sealed bearing, it may also be an oil impregnated brass fitting. By this arrangement, unit base 104 rotates with respect to shaft 206 . [0058] Cylindrical wall 230 preferably has a thickness of between 1 and 5 mm and is preferably about ½” to 2 inches in height. Wall 230 has a series of openings or holes 238 . These holes are positioned generally vertically with respect to the planar surface of bottom 228 . This enables various height positions. [0059] FIG. 5 is a plan view of the open end 240 of unit base 104 with cover 106 and shaft 206 removed. Unit base 104 supports lights 110 , electronics box 214 , and rechargeable batteries 216 . Lights 110 are electrically coupled to electronics box 214 , which is electrically coupled to batteries 216 , which, in turn, may be electrically coupled to generator 282 and/or solar panel 112 . [0060] Electronics box 214 is preferably secured to the inside of bottom 228 and is positioned off center. This provides room to fix jam nut 233 ( FIG. 2 ) onto shaft 206 inside unit base 104 . It also provides an off-center counterweight inside the upper section 202 that tends to keep the upper section 202 from rotating. Alternatively, electronics box 214 may be attached to the inside of cylindrical wall 230 or to the inside of cover 106 (preferably off-center). [0061] Electronics box 214 contains a modular circuit board (with circuitry shown in FIG. 20 ), which controls the functions of the wheel illumination system. Box 214 receives its electrical power from wiring harness 242 . Wiring harness 242 is coupled to rechargeable batteries 216 . Box 214 emits an electrical charge into wiring harness 244 . Wiring harness 244 is coupled to four lights 110 , each light 110 being mounted in and supported by a corresponding hole 234 . Lights 110 face outwards, toward the wheel. [0062] Rechargeable batteries 216 are preferably secured to bottom 228 of base 104 . Batteries 216 are positioned off center, like electronics box 214 , and for the same reason. Alternatively, batteries 216 may be attached to the inside surface of cylindrical wall 230 , or alternatively to the inside of cover 106 (preferably off-center). Batteries 216 may alternatively be coupled to upper section 202 in any position that allows the weight of the batteries to counterweight the upper section to control the amount of rotation as the wheel rotates and the automobile 98 travels down the road. [0063] Referring back to FIG. 2 , upper section 202 further includes a seal 246 that is generally circular and preferably made of rubber. Seal 246 is placed over the outside of cylindrical wall 230 and placed in either of two shallow grooves 248 . Grooves 248 are circular and extend around the outside of cylindrical wall 230 . Grooves 248 are spaced approximately a half an inch apart. Each groove 248 is parallel to bottom 228 of unit base 104 . Holes 234 are formed in the cylindrical wall 230 adjacent to each of parallel grooves 248 . Holes 234 are on the side of grooves 248 closer to bottom 228 . [0064] Cover 106 includes a cylindrical wall 250 that is slightly larger in diameter than cylindrical wall 230 of unit base 104 . The height of wall 250 is preferably between 1 and 3 inches. Several holes 252 are formed in cylindrical wall 250 that correspond in location with holes 238 in cylindrical wall 230 or preferably equal in number to holes 238 . [0065] Holes 252 and holes 238 are disposed and can be aligned such that fasteners 108 such as bolts, screws or rivets can be inserted into holes 252 and into holes 238 to removably fix cover 106 to unit base 104 . Cylindrical wall 250 is sized to cover cylindrical wall 230 and abut seal 246 . Seal 246 prevents water and other contaminants from leaking into upper section 202 between unit base 104 and cover 106 . [0066] Referring now to FIGS. 6-9 , alternative covers 106 include a top 254 that extends across and encloses cylindrical wall 250 . Top 254 may have various shapes, such as those shown in FIGS. 6-9 , including a flat top ( FIG. 6 ), a rounded top ( FIG. 7 ), a four-pointed spinner ( FIG. 8 ) and a three-pointed spinner ( FIG. 9 ). [0067] The outside diameter of cover 106 is preferably between 3 inches and 8 inches. Cover 106 is preferably composed of a lightweight metal or metal alloy, although various types of plastics or carbon fiber reinforced plastics may be used. Cover 106 is preferably reflective, having a chrome, chrome-plated, brushed, or polished aluminum finish. In the alternative, it may also be painted with visually pleasing paints such as metallic paints and fluorescent paints. It may also have patterns or designs on its outer surface. [0068] Illumination sources or lights 110 can be coupled directly to holes 234 , or alternatively, they can be mounted to holes 234 using light mounts, such as those light mounts shown in FIGS. 10-13 . Examples of these light mounts as installed can be found in FIG. 1,16 , 18 , and 19 . [0069] FIG. 10 shows a swiveling light mount 256 having a collar 258 that is fixed in hole 234 , and a flexible shaft 260 to which light 110 is coupled. FIG. 11 shows a gooseneck light mount 262 including a collar 264 that is fixed in hole 234 , and a flexible shaft 266 to which light 110 is coupled. FIG. 12 shows up a tubular light mount 268 having a collar 270 that is fixed to hole 234 and an elongated tubular shaft 272 to which light 110 is coupled. FIG. 13 shows an extension tube light mount 274 that includes a collar 276 from which two nested tubes 278 , 280 extend. Tubes 278 , 280 are nested, with tube 280 nested inside tube 278 . Tube 280 can be extended from tube 278 by pulling gently on the end of tube 280 . Light 110 is fixed to the end of tube 280 such that it can be extended and retracted whenever tube 280 is extended and retracted. [0070] In each of the examples of FIGS. 10-13 , light 110 is preferably an LED that extends outward away from its associated light mount and hole 234 , directing light outward away from device 100 and toward the wheel to which device 100 is mounted. These lights provide illumination for the wheel. Electrical power is provided to each of lights 110 in FIGS. 10-13 by wires (not shown) that are coupled to lights 110 , that extend through the light mounts and that pass through holes 234 in bottom 228 . FIG. 5 shows how electricity is carried to each of holes 234 . Each of the lights is electrically connected to the modular circuit board of electronics box 214 by wiring harness 244 . [0071] In an alternative embodiment, lights 110 , and light mounts 256 , 262 , 268 , 274 may be disposed in a similar matter on any or all of cover 106 , wall 230 , and wall 250 as they are on bottom 228 . In another alternative arrangement, lights 1110 need not be fixed to the outside of upper section 202 , but may be mounted inside upper section 202 as well. In this configuration, holes may be provided in the walls of upper section 202 , such as holes 234 in bottom 228 or other holes formed in unit base 104 or cover 106 , through which light from lights 1110 located inside upper section 202 radiate. [0072] Referring back to FIG. 2 , solar panel 112 is preferably fixed to the outer surface of top 254 of cover 106 , with electrical wires from solar panel 112 passing through an opening (not shown) in cover 106 . These wires are also coupled to rechargeable batteries 216 (see FIG. 5 ). Solar panel 112 is preferably circular, as shown in FIG. 2 , although it may be square or have an irregular shaped boundary. While a single solar panel is preferred, one or more solar panel 112 may be employed. [0073] The generator 282 is the power source of the device. The power supply is from the generator 282 with the solar panel 112 as the alternative, or can be used in addition to the generator 282 . [0074] The power source is shown FIGS. 14-15 . The power source includes a generator 282 which supplies electricity to lights 110 and serves to recharge batteries 216 . In FIGS. 14-15 , the electronics box, lights, and wiring harnesses (shown in FIG. 5 ) have been removed to better show the arrangement of generator 282 to unit base 104 . [0075] Generator 282 is mounted inside bottom 228 of unit base 104 . The stator of generator 282 is coupled to bottom 228 by adjustable mounting brackets 284 , which allow for various sizes of gears. Generator 282 has a rotor with a generator shaft 286 on which a generator gear 288 is mounted. Generator gear 288 , in turn, is engaged to shaft gear 290 , which is fixed to shaft 206 . Shaft 206 rotates with respect to upper section 202 whenever the vehicle is moving. [0076] When the vehicle is moving, the wheel assembly rotates. When the wheel assembly rotates, it rotates lower section 200 , which is fixed to the wheel assembly. Shaft 206 of lower section 200 rotates as the vehicle moves. Upper section 202 , however, does not rotate or rotates less than the rotation of the lower section 200 when the vehicle moves. Upper section 202 is eccentrically weighted by the off-center location of one or more of its internal components (the batteries, generator, and electronics box) or by the addition of special weights (not shown). Since upper section 202 is supported on a bearing and it is eccentrically weighted it does not rotate. [0077] Since shaft 206 rotates and upper section 202 does not rotate or rotates less than the rotation of the lower section 200 when the vehicle moves, relative motion between shaft 206 and a generator is provided. Shaft gear 290 turns generator gear 288 and drives the generator. When the generator is driven, it provides electricity to the electronics box and the batteries 216 to which it is connected by power supply leads 291 . The relative sizes of gears 288 and 290 can be varied to provide the desired electrical output. [0078] There are several preferred methods for attaching wheel illumination device 100 to wheel assembly 114 . These are illustrated in FIGS. 16-19 herein. [0079] In the first of these arrangements, shown in FIG. 16 , lower section 200 is fixed to the center of a hubcap (or hub cover) 292 . Hubcap 292 can be one provided by the automobile 98 manufacturer, or it may be a custom aftermarket hubcap. Hubcap 292 is fixed to wheel assembly 114 in the conventional manner. Fasteners 294 extend through holes 222 in base 204 to a lower better fit to surface being attached to if needed (such as concave or convex). The fasteners go through holes 222 . Fasteners 294 , in turn, pass through corresponding holes 296 in hubcap 292 , and are fixed thereto by nuts 298 threaded onto the free end of fasteners 294 . Before tightening nuts 298 , the operator adjusts the position of lower section 200 until shaft 206 of lower section 200 is coaxial with the axis of rotation of wheel assembly 114 . The operator then tightens nuts 298 . Holes 296 in hubcap 292 may be made by the aftermarket installer of wheel illumination system 100 on hubcap 292 . Slots 220 provide base 204 with some limited flexibility, permitting it to conform more easily with irregularly shaped hubcaps 292 . [0080] In a second arrangement, shown in FIG. 18 , a universal attachment plate 300 ( FIG. 17 ) is fixed to the free ends of lug nuts 302 of wheel assembly 114 . Base 204 of lower section 200 is subsequently fixed to plate 300 . Upper section 202 is subsequently fixed to lower section 200 . [0081] If the automobile 98 has one, the existing hubcap on the vehicle is removed and universal attachment plate 300 replaces it. Plate 300 has a plurality of holes 304 that are disposed about its periphery. These holes are selected and disposed to match several different lug nut patterns on a variety of automobiles. [0082] Universal attachment plate 300 is formed as a series of two (shown here) or three concentric rings, each of said rings having a plurality of holes 304 arranged to match different lug nut patterns. For larger vehicles with wider spaced lug nuts, plate 300 can be fixed to lug nuts 302 by bolts 306 passing through holes 304 in the outer concentric ring 308 . For smaller vehicles with closely spaced lug nuts, plate three can be fixed to lug nuts 302 by bolts 306 passing through holes 304 in the inner concentric ring 310 . In the event inner concentric ring 310 is fixed to lug nuts, outer concentric ring 308 can be removed by sawing through tabs 312 that couple the inner and outer concentric rings. The figures herein show two concentric rings that are connected by tabs 312 . In an alternative embodiment, an additional one or two concentric rings can be provided to match even larger lug nut patterns. [0083] Lug nuts 302 can be standard lug nuts provided by the automobile 98 manufacturer, or they can be custom lug nuts that are provided as an aftermarket product. The distance plate 300 is spaced away from wheel assembly 114 can be varied by selecting lug nuts of greater or lesser length. Longer or “extension” lug nuts are preferred. [0084] Base 204 is attached to plate 300 using threaded fasteners 294 . Fasteners 294 extend through holes 222 in base 204 . Fasteners 294 , in turn, pass through corresponding holes 304 in plate 300 , and are fixed thereto by nuts 298 that are threaded onto the free end of fasteners 294 . Before tightening nuts 298 , the operator adjusts the position of lower section 200 until shaft 206 is coaxial with the axis of rotation of wheel assembly 114 . The operator then tightens nuts 298 . [0085] In a third arrangement, shown in FIG. 19 , base 204 is not fixed directly to plate 300 , but is spaced away from plate 300 by hub cover 316 . Hub cover 316 is provided for use in situations when the hub of wheel assembly 114 extends outward away from the wheel too far to permit base 204 to be attached to directly to plate 300 . [0086] Hub cover 316 is a hollow right circular cylindrical body 318 having a first enclosed end 320 and a circular flange 322 extending radially outward from a second end of body 318 about the entire circumference of body 318 . Flange 322 is planar and is fixed to plate 300 with threaded fasteners 294 . Fasteners 294 extend through holes 324 in flange 322 , and then through corresponding holes 314 in plate 300 . Nuts 298 are threaded onto the free end of fasteners 294 and are tightened. This arrangement fixes hub cover 316 to plate 300 . [0087] Base 204 is attached to hub cover 316 using threaded fasteners 294 . Fasteners 294 extend through holes 222 in base 204 . Fasteners 294 , in turn, pass through corresponding holes 326 in first enclosed end 320 of hub cover 316 , and are fixed thereto by nuts 298 that are threaded onto the free end of fasteners 294 inside hub cover 316 . [0088] Before tightening nuts 298 inside hub cover 316 , the operator adjusts the position of lower section 200 until shaft 206 is coaxial with the axis of rotation of wheel assembly 114 . The operator then tightens nuts 298 . [0089] FIG. 20 is a schematic illustrating the control circuit 330 formed on the modular circuit board in the electronics box, together with the power source and battery. The core of the control circuit 330 is microprocessor 332 , which controls the operation of the entire control circuit. Microprocessor 332 is coupled to a radio receiver 334 for receiving remote commands that control the device 100 , a speed sensor 336 , power conversion and conditioning circuitry 338 , lighting power conversion circuitry 340 , and lighting control circuitry 342 . Lights 110 are coupled to lighting control circuitry 342 from which they receive their electrical signals and responsively generate light. Control circuit 330 also includes a power storage circuit 344 which includes rechargeable batteries 216 . Power storage circuit 344 is coupled to power conversion and conditioning circuit 338 . Solar panel 112 and generator 282 are also coupled to power conversion and conditioning circuit 338 to provide electrical power to the control circuit and the lights. Power transfer system 346 is also coupled to power conversion and conditioning circuit 338 to control the direction and flow of electrical power to and from the batteries 216 , the generator 282 , the solar panel 112 , and the microprocessor 332 . [0090] Microprocessor 332 receives its power from power conversion and conditioning circuit 338 . Power conversion and conditioning circuit 338 regulates the electricity supplied by solar panel 112 and power generator 282 , as well as power storage circuit 344 . As power is used by the power storage circuit 344 , power conversion and conditioning circuit 338 directs electrical power from power generator 282 and solar panel 112 to power storage circuit 344 . [0091] Microprocessor 332 is configured to receive speed signals from speed sensor 336 . Microprocessor 332 is also configured to receive commands from radio receiver 334 , which in turn receives commands from the operator in the automobile 98 (see FIG. 21 , below). [0092] In response to these commands, microprocessor 332 is configured to control the direction and amount of electrical power provided to lights 110 . Microprocessor 332 does this by signaling lighting control circuit 342 . Lighting control circuit 342 regulates the flow of electricity from lighting power conversion circuit 340 . Lighting power conversion circuit 340 regulates the voltage of the electrical power provided by power conversion and conditioning circuit 338 to a level that is compatible with lights 110 . [0093] Microprocessor 332 is programmed to selectively generate different patterns of light emitted by lights 110 . It does this by calculating the duration and intensity of light that is required from lights 110 and signaling lighting control circuit 342 accordingly. Microprocessor 332 is preprogrammed to generate several patterns when requested by the user via radio receiver 334 . [0094] Microprocessor 332 is programmed to change the color of lights 110 by turning lights 110 of one color off and turning lights 110 of another color on. Microprocessor 332 is programmed to flash lights 110 by turning them on and off at a preprogrammed interval. Microprocessor 332 is further programmed to fairy the preprogrammed interval at which it turns the lights on and off. Microprocessor 332 is programmed to monitor speed sensor 336 and determine when the automobile 98 is stationary or moving at a predetermined speed. Microprocessor 332 is programmed to turn lights 110 off when the vehicle and the wheel assembly are stationary. Microprocessor 332 is also programmed in another mode of operation to turn lights 110 on when the vehicle and the wheel assembly start moving. Microprocessor 332 is also programmed to turn lights 110 on when the vehicle and the wheel assembly begin moving. Microprocessor 332 can change the speed of the patterns automatically by monitoring the speed of the vehicle and the wheel assembly using speed sensor 336 . Microprocessor 332 is programmed to vary the light intensity with the volume of a sound signal provided by the user via radio receiver 334 . In this manner, microprocessor 332 is configured to change the intensity of the plurality of lights 110 in synchrony with an audio source transmitted from the user to control circuit 330 via radio receiver 334 . [0095] In FIG. 21 we see a remote control system 364 configured to transmit operator commands and audio signals to wheel illumination system 100 via a radio transmitter 354 ( FIG. 20 ). Remote control system 364 includes a microprocessor 348 that receives operator mode selections from mode selection input device 350 , and receives an audio signal from sound conditioning and conversion circuit 358 . In response to these signals, microprocessor 348 transmits light command signals to radio transmitter 354 . Radio transmitter 354 , in turn, transmits these light command signals to radio receiver 334 (see FIG. 20 ) of the wheel illumination system 100 . When radio receiver 334 receives these signals, it transmits them to microprocessor 332 of wheel illumination system 100 , which responsively commands lighting control circuit 342 to generate the requested light patterns. In this manner, the user (who is preferably inside the operator's compartment of the automobile 98 ) can change the mode of operation of the wheel illumination system 100 and the patterns of light generated by lights 110 in real time as the automobile 98 travels down the road. [0096] The user or operator communicates with microprocessor 348 by entering commands into mode selection input device 350 . Mode selection input device 350 is preferably a touch screen display, incorporating a screen (status display 352 ) and a pressure sensitive transparent switching surface (mode selection input device 350 ). As the operator presses the touch screen, microprocessor 348 presents the user with a series of menus that are displayed on the touch screen. The operator can select whether to (1) turn the lights off, (2) turn the lights on, (3) turn the lights off automatically when the vehicle stops moving, (4) turn the lights on automatically when the vehicle stops moving, (5) turn the lights on automatically when the vehicle starts moving, (6) transmit sound intensity signals from a microphone 362 to the wheel illumination system 100 , (7) transmit sound intensity signals from an external audio input 360 (from an audio source such as car stereo, car CD, satellite radio, terrestrial radio or the like) to the wheel illumination system 100 , (8) select a desired color for lights 110 , (9) select a desired rate at which to flash or blink lights 110 . [0097] The two microprocessors shown herein are preferably Microchip PIC microprocessors or Amtel. The patterns are stored in the NVRAM of the PIC microprocessors. The user selects the patterns from the touch screen/selection menu of the remote control system. The user selects specific colors by selecting predetermined modes of operation from the touch screen. Using the speed sensor, the wheel unit could time the pulses of light so as to create the illusion of the wheels rotating in either a counterclockwise or clockwise pace. The user selects specific colors by selecting predetermined modes of operation from the touch screen or selects custom color schemes using the same interface. To create a new pattern the user selects them using the remote control system, or downloads new patterns into the controller. The power may be provided by a power transit options system (e.g. a magnetic induction power systems such as used for security cards and rechargeable toothbrushes) or direct connect systems (rotor on back of wheel with contacts). The transmitter and receiver communicate over radio frequencies. Alternatively, other electromagnetic data link methods may be used as well these other methods within the electromagnetic spectrum include infrared and magnetic inductance data links. [0098] One will appreciate that the present disclosure is intended as an exemplification of the invention, and is not intended to limit the invention to the specific embodiment illustrated. The disclosure is intended to cover by the appended claims all such modifications as fall within the scope of the claims.

A system for illuminating a motor vehicle wheel assembly of a motor vehicle is provided, the system including a mount configured to be fixed to the wheel assembly, a plurality of lights fixed to the mount, a control circuit coupled to the plurality of lights to regulate a flow of electricity to the plurality of lights; and a power source coupled to the control circuit to provide said control circuit with electrical power for the lights, wherein the power source includes an electrical energy generating element as well as an electrical energy storing element.

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application is a divisional of U.S. application Ser. No. 10/970,290, filed Oct. 21, 2004, and is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2003-363925, filed Oct. 23, 2003, the entire contents of each of which are incorporated herein by reference. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to an electronic device having a hinge that joins a body and a display. More particularly, the present invention is concerned with the electronic device in which an outer space in the hinge is effectively utilized. [0004] 2. Description of the Related Art [0005] Notebook computers have been known for some time as an electronic device with a body and a display which can freely be opened away from the body and closed onto the body. [0006] In the electronic device, for example, as disclosed in Patent Document 1, a power switch is flush with a keyboard included in the body. Moreover, in the electronic device disclosed in Patent Document 2, the power switch is juxtaposed with other operation switches on the lateral side of the body. Moreover, since a motherboard is incorporated in the body, connectors allowing linkage with external equipment or a communication line are disposed on the lateral side or rear side of the body. [Patent Document 1] Japanese Unexamined Patent Publication No. 2002-108505 [Patent Document 2] Japanese Unexamined Patent Publication No. 2002-7048 [0009] In recent years, the electronic device has become more and more compact. There is difficulty in preserving a space, in which components are disposed, in a body and a display alike. Moreover, for realization of thinner equipment, it proves effective to limit the number of components to be incorporated in the body. The present inventor et al. have given attention to a space created at an outer end of the shaft of a hinge other than the body and the display. A power switch or a connector that are conventionally included in the body is disposed in the space in efforts to thin the body. SUMMARY OF THE INVENTION [0010] In one aspect, an electronic device in accordance with the present invention comprises a body, a display, and a hinge that joins the body and display so that they can freely be opened or closed. A power switch is formed at an edge of the shaft of the hinge. [0011] In another aspect, the electronic device in accordance with the present invention comprises a body, a display, and a hinge that joins the body and display so that they can be freely opened or closed. A port of a connector opens at an end of the shaft of the hinge. [0012] As mentioned above, since the power switch or connector is disposed in a space at an end of the shaft of a hinge which has been left unused as a so-called dead space in the past, the freedom in disposing components in the body or display is expanded accordingly. By devising the layout of the components, thinning of the body and display is facilitated. [0013] According to the electronic device in which the present invention is implemented, a power switch is disposed at an end of the shaft of a hinge. A space in the electronic device that has not been used at all in the past can be utilized effectively. The number of components to be incorporated in the body can be reduced, and the freedom in laying out components is expanded accordingly. [0014] Consequently, the body can be further thinned. [0015] Moreover, since the power switch is disposed away from a keyboard and other operation buttons, the power switch can be prevented from being pressed by mistake and accurately manipulated. [0016] Moreover, according to the electronic device in which the present invention is implemented, a port of a connector opens at an end of the shaft of a hinge. A space present in electronic device that is conventionally not used at all can be utilized effectively. The number of components to be incorporated in a body can be reduced. The freedom in laying out components is expanded accordingly. [0017] Consequently, the body can be further thinned. BRIEF DESCRIPTION OF THE DRAWINGS [0018] FIG. 1 is a perspective view of an electronic device according to an embodiment of the invention in an opened state; [0019] FIG. 2 is a perspective view of the electronic device in a closed state; [0020] FIG. 3 is a plan view of the inside of a lower section 27 of a case 26 of the electronic device; [0021] FIG. 4 is a side view of the lower section 27 as seen along the arrows [ 4 ] and [ 4 ] of FIG. 3 ; [0022] FIG. 5 is a plan view of the built-in components disposed in the case 26 ; [0023] FIG. 6 is a plan view of one surface of a motherboard to be fitted into the case 26 ; [0024] FIG. 7 shows the other surface of the motherboard shown in FIG. 6 ; [0025] FIG. 8 is a plan view of connectors and a flexible wiring board provided in the case 26 ; [0026] FIG. 9 is a front view of the connectors and the flexible wiring board of FIG. 8 ; [0027] FIG. 10 is an enlarged front view of the connectors shown in FIGS. 8 and 9 ; [0028] FIG. 11 is a plan view of a keyboard fitted into the case 26 ; [0029] FIG. 12 is a front view of the keyboard; [0030] FIG. 13 is a rear view of the keyboard; [0031] FIG. 14 is a left-side view of the keyboard; [0032] FIG. 15 is a right-side view of the keyboard; [0033] FIG. 16 is a back side view of the keyboard; [0034] FIG. 17 is a plan view of the inside of the upper section 28 of the case 26 ; [0035] FIG. 18 is a schematic cross section of the inside of the case 26 where heat-generating components are placed; [0036] FIG. 19 is a plan view of the inside of a case 22 ; [0037] FIG. 20 is a side view of the case 22 as seen along the arrows [ 20 ] and [ 20 ] in FIG. 19 ; [0038] FIG. 21 is a plan view of a liquid crystal panel and an inverter circuit board fitted in the inside of the case 22 ; [0039] FIG. 22 is an enlarged plan view of a principal part of the liquid crystal panel being housed in the case 22 ; [0040] FIG. 23 is an enlarged view of one of the two constituent parts of hinges formed at the back of the case 22 ; [0041] FIG. 24 is an enlarged view of the other constituent part of the hinges formed at the back of the case 22 ; [0042] FIG. 25 is a schematic diagram showing a construction of a power switch installed in the constituent part of the hinge shown in FIG. 23 ; [0043] FIGS. 26A and 26B are schematic cross sections of the laminated structure of the case 22 of the electronic device according to the present embodiment; [0044] FIGS. 27A and 27B show the pieces of conductor foil being stuck onto the laminated layer of FIGS. 26A and 26B ; [0045] FIG. 28 shows a resin material being stuck onto edge portions of the laminated layers shown in FIG. 26 ; [0046] FIG. 29 is an enlarged view of the rear portion of the electronic device in an opened state according to the present embodiment; and [0047] FIG. 30 is an enlarged view of the front edge portion of the electronic device in a closed state according to the present embodiment. DESCRIPTION OF THE PREFERRED EMBODIMENTS [0048] Now, an embodiment of an electronic device in accordance with the present invention will be described below. The embodiment is a notebook computer. [0049] FIGS. 1 and 2 show the outer appearances of the electronic device 1 of the present embodiment. The electronic device 1 comprises a body 3 , a display 5 , and two hinges “h” which fasten the display 5 to the body 3 . [0050] The display 5 pivots on the hinges “h” to open away from the body 3 and close onto the body 3 . In FIG. 1 , the display 5 is opened away from the body 3 . In FIG. 2 , the display 5 is closed onto the body 3 . [0051] The body 3 has a case 26 . Disposed in the case 26 as shown in FIG. 5 are a keyboard 11 , a motherboard 30 , a hard-disk drive 32 , a PC card slot 34 , and connectors 40 a - d. [0052] The keyboard 11 is an input unit of the electronic device 1 . The motherboard 30 is the substantially main functional component of the electronic device 1 and receives signals inputted through the keyboard 11 and makes various kinds of processing such as arithmetic processing, control processing, image processing, and processing to output signals to the display 5 . [0053] The motherboard 30 serves as a control circuit board to control individual components such as the keyboard 11 and the display 5 , too. [0054] The case 26 comprises an upper section 28 and a lower section 27 . FIG. 3 is a plan view of the inside of the lower section 27 . [0055] FIG. 4 is a side view of the lower section 27 as seen along the arrows [ 4 ] and [ 4 ] of FIG. 3 . [0056] The lower section 27 looks like a flat box and has an almost rectangular bottom plate 27 a , right and left side plates 27 b and 27 d , and a back plate 27 c . As shown in FIGS. 3 and 4 , the side and back plates 27 b - d are erected on the three sides of the bottom plate 27 a. [0057] The back plate 27 c is erected on the back side of the bottom plate 27 a and has outward-protruding constituent parts 42 a and 42 b of the hinges “h” as shown in FIGS. 3 and 4 . [0058] As shown in FIGS. 3 and 4 , there are cuts 43 a - d in the left side plate 27 b for the connectors 40 a - d and a cut 43 e in the right side plate 27 d for the PC card slot 34 . [0059] The inside of the bottom plate 27 a is provided with a resin mold 45 , which is raised from the inside surface of the bottom plate 27 a to reinforce the lower section 27 against bending and twisting. [0060] A heat-transmitting sheet 47 is stuck on the inside surface of the bottom plate 27 a . The heat-transmitting sheet 47 is positioned near to the center between the right and left sides of the bottom plate 27 a and one-sided toward the back side of the bottom plate 27 a. [0061] The heat-transmitting sheet 47 is, for example, a graphite sheet 0.1 to 1.0 mm thick. Because the heat-transmitting sheet 47 is positioned in an area where the mold 45 does not exist, the heat-transmitting sheet 47 does not float, but is closely stuck onto the inside of the bottom plate 27 a ; accordingly, the heat from heat-generating components to be described later is diffused effectively through the lower section 27 . [0062] An elastic sheet 48 is laid between the heat-transmitting sheet 47 and the bottom plate 27 a . The elastic sheet 48 is rectangular and larger than the heat-generating components. The elastic sheet 48 is positioned substantially in the middle of the lateral width of the lower section 27 within about a half of the bottom 27 a near the wall portion 27 c. [0063] To be specific, the elastic sheet 48 is 0.5-3.0 mm thick and made of Poron (of Rogers Inoac Corporation) which is high-density polyurethane foam whose cells are fine and uniform. [0064] An insulating sheet 49 is overlaid on the heat-transmitting sheet 47 ; accordingly, short circuits between the heat-transmitting sheet 47 , which is made of graphite and conductive, and the motherboard, which is put on the heat-transmitting sheet 47 , are prevented. [0065] The insulating sheet 49 is, for example, a transparent thin film of polyphenylene sulfide. It is as thin as, for example, 0.05-0.3 mm; therefore, it does not prevent heat transmission from the heat-generating components to the heat-transmitting sheet 47 . [0066] The lower section 27 is made of CFRP (carbon fiber reinforced plastics). To be specific, the CFRP consists of six layers 51 a , 51 b , 52 a , 52 b , 53 a , and 53 b as shown in FIG. 26 . [0067] As shown in FIG. 26A , the six layers 51 a , 51 b , 52 a , 52 b , 53 a , and 53 b are pressed together. [0068] Each layer is made of long carbon fibers solidified by epoxy resin. All the fibers of each layer are put side by side in one and the same direction. [0069] To be specific, the carbon fibers of the innermost layers 51 a and 51 b are laid in the longitudinal direction of the electronic device 1 . Accordingly, the carbon fibers of the layer 51 a are parallel to those of the layer 51 b. [0070] The carbon fibers of the intermediate layers 52 a and 52 b are laid in the lateral direction of the electronic device 1 . [0071] The carbon fibers of the outermost layers 53 a and 53 b are laid in the direction at angles of 45° with the longitudinal and lateral directions of the electronic device 1 . Accordingly, the carbon fibers of the layer 53 a are parallel to those of the layer 53 b. [0072] With the above laminated structure, the thin lower section 27 has sufficient strength. As the lower section 27 is thin, the electronic device 1 is also thin, which is an advantage for portable electronic devices in particular. [0073] As shown in FIG. 28 , an insulating layer 56 is formed on the inside surface of the bottom plate 27 a . The insulating layer 56 is made of, for example, nylon (a trade name of Du Pont). [0074] The insulating layer 56 prevents short circuits between the lower section 27 , which is made of CFRP (carbon fiber reinforced plastics) containing conductive carbon fibers, and the motherboard 30 fitted in the lower section 27 . [0075] When the insulating layer 56 made of nylon is heated, it softens and becomes adhesive. By making use of the adhesiveness of the insulating layer 56 , the mold 45 is stuck and fixed to the insulating layer 56 . The mold 45 has bosses with threaded holes, etc. [0076] As shown in FIG. 28 , the front edge of the lower section 27 is provided with a resin cover 45 a . By making use of the adhesiveness of the insulating layer 56 , the cover 45 a is stuck onto the insulating layer 56 to cover the front edge of the lower section 27 . Thus, loose ends of carbon fibers, if any, at the front edge of the lower section 27 are covered up. [0077] As shown in FIG. 3 , because the resin cover 45 a extends along the front edge of the lower section 27 , it serves as a beam, too, reinforcing the lower section 27 against bending and twisting. [0078] The resin cover 45 a and the mold 45 are made of nylon as well as the insulating layer 56 ; accordingly, the cover 45 a and the mold 45 are stuck on the insulating layer 56 sufficiently. As shown in FIG. 28 , a groove 54 is made in the surface of the resin cover 45 a which comes in contact with the insulating layer 56 . When the insulating layer 56 is heated and softened and the cover 45 a is stuck on the insulating layer 56 , surplus softened, adhesive nylon enters into the groove 54 . [0079] Thus, the surplus softened, adhesive nylon is prevented from leaking out through the joint between the lower section 27 and the cover 45 a . If the surplus softened, adhesive nylon leaks out, the appearance of the electronic device 1 is spoiled. [0080] Because the right and left side plates 27 b and 27 d are erected on the right and left sides, respectively, and the back plate 27 c is erected on the back side of the bottom plate 27 a , these plates 27 b , 27 c , and 27 d play the role of the cover 45 a. [0081] Now, the motherboard to be fitted in the lower section 27 will be described below by referring to FIGS. 6 and 7 . FIG. 6 shows the upper surface of the motherboard 30 ; FIG. 7 , the lower surface. A central processor 58 is mounted on the upper surface. An image processor 60 and a plurality of semiconductor memories 62 are mounted on the lower surface. Although not shown in FIGS. 6 and 7 , many other components are mounted on both the surfaces of the motherboard 30 . [0082] The central processor 58 and the image processor 60 are semiconductors and generate heat when they function. The central processor 58 and the image processor 60 are so positioned that they do not overlap with each other. [0083] The motherboard 30 comprises a multi-layer printed circuit board and the central processor 58 , the image processor 60 , the semiconductor memories 62 , and other components (not shown) mounted on both the surfaces of a multi-layer printed circuit board and is the substantial body of the electronic device 1 in terms of functions of the electronic device 1 . [0084] The multi-layer printed circuit board is made by the buildup method as follows. A two-layer printed circuit board (hereinafter “intermediate two-layer printed circuit board”) is laid on each of the upper and lower surfaces of an innermost two-layer printed circuit board. A single-layer printed circuit board is laid on the upper surface of the upper intermediate two-layer printed circuit board; a single-layer printed circuit board, on the lower surface of the lower intermediate two-layer printed circuit board. A single-layer printed circuit board is laid on the upper surface of the upper single-layer printed circuit board; a single-layer printed circuit board, on the lower surface of the lower single-layer printed circuit board. Thus, a ten-layer printed circuit board is made. The buildup method enables us to do wiring efficiently and high-density mounting of parts. [0085] The connectors 40 a - d shown in FIGS. 8-10 are also fitted in the lower section 27 . The connectors 40 a - d are connected to the motherboard 30 through a flexible wiring board 67 . Namely, the connectors 40 a - d are connected to wires at one end of the flexible wiring board 67 , and the other end 67 a of the flexible wiring board 67 is inserted into a connector mounted on the motherboard 30 . [0086] As shown in FIG. 10 , the connector 40 b is provided two flanges 64 protruding from the right and left shorter sides of its socket. By fixing the flanges 64 to the left side plate 27 b by using, for example, screws, the connector 40 b can be fixed to the left side plate 27 b . The connector 40 c has the same flanges 64 as the connector 40 b. [0087] The keyboard 11 shown in FIGS. 11-16 is fitted to the lower section 27 . FIG. 11 is a plan view of the keyboard 11 . FIGS. 12 and 13 are front and rear views, respectively, of the keyboard 11 . FIGS. 14 and 15 are left and right side views, respectively, of the keyboard 11 . FIG. 16 is a bottom view of the keyboard 11 . [0088] The keyboard 11 comprises a case 37 , input keys 13 , a pointing device 14 called “track point,” and a cover 36 . [0089] The case 37 is made of, for example, magnesium and in the shape of a flat box, having a key-arrangement area and side plates erected around the key-arrangement area. [0090] The key-arrangement area is in the shape of an almost rectangular flat plate and the side plates are formed, as a single piece, at the right, left, top, and bottom sides of the key-arrangement area. [0091] As described above, the case 37 is not a flat plate, but in the shape of a flat box, having the side plates; accordingly, its rigidity is high. When a user presses keys 13 , the case 37 does not warp, giving good repulsion to the fingers of the user. Thus, the feeling of key operation is good. [0092] The four sides of each key of an ordinary keyboard are inclined, whereas the four sides of input keys 13 are not inclined. Accordingly, the occupancy area of each input key 13 is smaller than that of an ordinary key. Accordingly, the gaps between input keys 13 can be widened to prevent the user from pressing wrong input keys 13 . [0093] The cover 36 has cuts in it, and the input keys 13 and the pointing device 14 are exposed through the cuts. The key-arrangement area is covered with the cover 36 . Thus, the gaps between input keys 13 are covered and, hence, dust and water are prevented from entering through the gaps. The cover 36 and the input keys 13 are made of, for example, ABS resin. [0094] Now, the upper section 28 of the case 26 will be described below by referring to FIG. 17 . FIG. 17 is a plan view of the inside of the upper section 28 which faces the inside of the lower section 27 shown in FIG. 3 . [0095] The upper section 28 is almost rectangular and has approximately the same area as the lower section 27 . The upper section 28 has a large cut 80 in its front area wherein the input keys 13 and the pointing device 14 are arranged. [0096] The reference numeral 81 in FIG. 17 is a covered area. Outward-protruding constituent parts 74 a and 74 b of the hinges “h” are formed at the back side of the covered area 81 . [0097] A heat-transmitting sheet 72 is stuck to the inside of the covered area 81 . The heat-transmitting sheet 72 is positioned near to the center between the right and left sides of the covered area 81 . [0098] The heat-transmitting sheet 72 is made of, for example, graphite and 0.1-1.0 mm thick. The heat-transmitting sheet 72 is shaped and has cuts in it so as to avoid bosses and ribs erected inside the covered area 81 . Thus, the covered area 81 is not floated over the inside surface of the covered area 81 , but closely stuck onto the inside surface; accordingly, the heat from heat-generating components is effectively diffused through the upper section 28 . [0099] An elastic sheet 83 is laid between the heat-transmitting sheet 72 and the inside surface of the covered area 81 . The elastic sheet 83 is rectangular and larger than the heat-generating components in contact with the heat-transmitting sheet 72 . The elastic sheet 83 is positioned near to the center between the right and left sides of the covered area 81 . [0100] To be specific, the elastic sheet 83 is 0.5-3.0 mm thick and made of Poron (of Rogers Inoac Corporation) which is high-density polyurethane foam whose cells are fine and uniform. [0101] An insulating sheet (not shown) is overlaid on the heat-transmitting sheet 72 ; accordingly, short circuits between the heat-transmitting sheet 72 , which is made of graphite and conductive, and the motherboard 30 , which is put on the heat-transmitting sheet 72 , are prevented. [0102] The insulating sheet is, for example, a transparent film of polyphenylene sulfide. It is as thin as, for example, 0.05-0.3 mm; therefore, it does not prevent heat transmission from the heat-generating components to the heat-transmitting sheet 72 . [0103] The lower section 27 and the upper section 28 are coupled by, for example, screws. At this time, the keyboard 11 , motherboard 30 , hard-disk drive 32 , and PC card slot 34 are fitted in the inside of the lower section 27 . [0104] The cooling mechanism for the central processor 58 and the image processor 60 , which are mounted on the upper and lower surfaces, respectively, of the motherboard 30 and generate heat, will be described below by referring to FIG. 18 . [0105] The lower surface, on which the image processor 60 is mounted, of the motherboard 30 faces the inside of the lower section 27 . The upper surface, on which the central processor 58 is mounted, faces the inside of the upper section 28 . [0106] The image processor 60 is in contact with the part of the heat-transmitting sheet 47 raised by the elastic sheet 48 . In this way, the image processor 60 is put in close contact with the heat-transmitting sheet 47 by the elasticity of the elastic sheet 48 . Thus, air is precluded from between the image processor 60 and the heat-transmitting sheet 47 and the heat from the image processor 60 is efficiently transmitted to the heat-transmitting sheet 47 . [0107] The heat transmitted to the heat-transmitting sheet 47 is diffused through the heat-transmitting sheet 47 and the lower section 27 . Thus, overheat of the image processor 60 is prevented. [0108] The central processor 58 is in contact with the part of the heat-transmitting sheet 72 lowered by the elastic sheet 83 . In this way, the central processor 58 is put in close contact with the heat-transmitting sheet 72 by the elasticity of the elastic sheet 83 . Thus, air is precluded from between the central processor 58 and the heat-transmitting sheet 72 and the heat from the central processor 58 is efficiently transmitted to the heat-transmitting sheet 72 . [0109] The heat transmitted to the heat-transmitting sheet is diffused through the heat-transmitting sheet 72 and the upper section 28 . Thus, overheat of the central processor 58 is prevented. [0110] The central processor 58 and the image processor 60 are so positioned that they do not overlap with each other and, hence, the heat from the central processor 58 and the image processor 60 is not concentrated at a single spot. Beside, this arrangement of the central processor 58 and the image processor 60 enables the reduction of the distance between the lower section 27 and the upper section 28 and, hence, the reduction of the body 3 . [0111] The semiconductor memories 62 (see FIG. 7 ) mounted on the lower surface of the motherboard 30 are also in contact with the heat-transmitting sheet 47 and their heat is diffused through the heat-transmitting sheet 47 . [0112] The hard-disk drive 32 as that is a storage device, which is positioned to the left of the motherboard 30 in FIG. 5 , will be described below. [0113] As shown in FIG. 3 , ribs 46 are formed in the four corners of a hard disk drive-mounting space 44 in the lower section 27 . In addition, as shown in FIG. 17 , ribs 78 are formed in the four corners of a hard disk drive-mounting space 76 in the upper section 28 . [0114] Accordingly, the hard-disk drive 32 is supported by the ribs 46 and 78 , a gap of the height of ribs 78 kept between the top surface of the hard-disk drive 32 and the inside surface of the upper section 28 , a gap of the height of ribs 46 kept between the bottom surface of the hard-disk drive 32 and the inside surface of the lower section 27 . [0115] There are small gaps in spots, where the connectors 40 a - d (see FIG. 5 ) are mounted to expose their sockets, of the left side plates of the lower section 27 and the upper section 28 . The inside and the outside of the case 26 are connected by the small gaps. The space in which the motherboard 30 is fitted and the outside of the case 26 can be connected by the small gaps and the gaps on and under the hard-disk drive 32 . [0116] Accordingly, the discharge of heat from the central processor 58 and the image processor 60 can be accelerated. Besides, the hard-disk drive 32 can be air-cooled. [0117] The connectors 40 a - d are connected to the motherboard through the flexible wiring board 67 (see FIG. 8 ). The flexible wiring board 67 is routed through the gap between the bottom surface of the hard-disk drive 32 and the inside surface of the lower section 27 . [0118] Because the connectors 40 a - d are not mounted directly on the motherboard 30 , shock at the time of connection and disconnection of external cables to and from the connectors 40 a - d is absorbed by the flexible wiring board 67 . Thus, the shock is not transmitted to the motherboard 30 , damage to and positional slippage of the motherboard 30 prevented. [0119] As shown in FIGS. 8 and 9 , the connectors 40 b and 40 c are disposed so that the right flange 64 of the connector 40 b and the left flange 64 of the connector 40 c overlap with each other. The two flanges 64 overlapping with each other are fixed to the left side plate of the lower section 27 with, for example, a screw. Thus, the space to mount the connectors 40 a - d is saved by the space of one flange 64 . [0120] As shown in FIG. 5 , the PC card slot 34 is disposed at the right side of the case 26 . The PC card is the standards for card-type peripheral devices established jointly by PCMCIA (Personal Computer Memory Card International Association) and JEIDA (Japan Electronic Industry Development Association). [0121] The keyboard 11 is disposed in the space along the front of the case 26 . The input keys 13 and the pointing device 14 are exposed to the outside through the cut 80 in the upper section 28 . [0122] As described above, the motherboard 30 , hard-disk drive 32 , and PC card slot 34 are disposed in the space along the back of the case 26 and the keyboard 11 is disposed in the space along the front of the case 26 . [0123] Cuts are made in the right and left sides of the motherboard 30 to avoid the hard-disk drive 32 and the PC card slot 34 . The keyboard 11 does not overlap with the central processor 58 or the image processor 60 mounted on the motherboard 30 or the hard-disk drive 32 or the PC card slot 34 . [0124] As described above, because built-in components are arranged without their overlapping with one another, the body 3 can be made thin. [0125] Part of the motherboard 30 is placed under the keyboard 11 , but the central processor 58 and the image processor 60 , which account for a large part of the thickness of the motherboard 30 , do not overlap with the keyboard 11 . Accordingly, the body 3 is not prevented from being made thin. An insulating sheet made of, for example, polycarbonate is laid between the part of the motherboard 30 overlapping with the keyboard 11 and the keyboard 11 in order to prevent short circuits between the case 37 of conductive magnesium and the motherboard 30 . The motherboard 30 and the keyboard 11 may be arranged so that they do not overlap with each other at all. [0126] Because the heat-generating central processor 58 and image processor 60 do not overlap with the keyboard 11 , the heat of neither the central processor 58 nor the image processor 60 is transmitted to the keyboard 11 to annoy the user. [0127] Because the central processor 58 and the image processor 60 are disposed in the space along the back side of the case 26 and the keyboard 11 is disposed in the space along the front side of the case 26 , the user can operate the keyboard 11 without touching the upper section 28 covering the central processor 58 and the image processor 60 . [0128] The central processor 58 and the image processor 60 are positioned near to the center between the right and left sides of the case 26 ; accordingly, less heat is transmitted from the central processor 58 and the image processor 60 to the user's right and left hands which tend to be positioned toward the right and left sides of the keyboard 11 , respectively. When the user moves the electronic device 1 with the display 5 opened, the user holds the right and left sides of the part of the body 3 behind the keyboard 11 ; accordingly, less heat is transmitted from the central processor 58 and the image processor 60 to the hands of the user. [0129] Because the most heat-generating image processor 60 is mounted on the lower surface of the motherboard 30 , less heat is transmitted from the image processor 60 to the top, or keyboard, side of the body 3 , less annoying the user. [0130] Now, the display 5 will next be described. The display 5 comprises a case 22 (see FIG. 19 ), a liquid crystal panel 7 (see FIG. 21 ) housed in the case 22 , and an inverter circuit board 93 (see FIG. 21 ). [0131] FIG. 19 is a plan view of the inside of the case 22 . FIG. 20 is a side view of the case 22 as seen along the arrows [ 20 ] and [ 20 ] in FIG. 19 . The case 22 is almost rectangular and side plates are erected at the right and left sides of the case 22 . [0132] Outward-protruding constituent parts 87 a and 87 b of the hinges “h” are formed at the right and left ends of the back side of the case 22 . [0133] Molds 85 a - d are provided inside the case 22 . The molds 85 a - d are disposed so that they enclose the four sides of the case 22 and reinforce the case 22 against bending and twisting. [0134] In the same way as the lower section 27 , the case 22 is made of CFRP (carbon fiber reinforced plastics). To be specific, the CFRP consists of six layers 51 a , 51 b , 52 a , 52 b , 53 a , and 53 b as shown in FIG. 26 . [0135] As shown in FIG. 26A , the six layers 51 a , 51 b , 52 a , 52 b , 53 a , and 53 b are pressed together. [0136] Each layer is made of long carbon fibers solidified by epoxy resin. All the fibers of each layer are put side by side in one and the same direction. [0137] To be concrete, the carbon fibers of the innermost layers 51 a and 51 b are laid in the longitudinal direction of the electronic device 1 . Accordingly, the carbon fibers of the layer 51 a are parallel to those of the layer 51 b. [0138] The carbon fibers of the intermediate layers 52 a and 52 b are laid in the lateral direction of the electronic device 1 . [0139] The carbon fibers of the outermost layers 53 a and 53 b are laid in the direction at angles of 45° with the longitudinal and lateral directions of the electronic device 1 . Accordingly, the carbon fibers of the layer 53 a are parallel to those of the layer 53 b. [0140] With the above laminated structure, the thin case 22 has sufficient strength. As the case 22 as well as the lower section 27 is thin, the electronic device 1 is also thin, which is an advantage for portable electronic devices in particular. [0141] As shown in FIG. 28 , an insulating layer 56 is formed on the inside surface of the case 22 . The insulating layer 56 is made of, for example, nylon (a trade name of Du Pont). [0142] The insulating layer 56 prevents short circuits between the case 22 made of CFRP containing conductive carbon fibers and the liquid crystal panel 7 , the inverter circuit board 93 , etc. housed in the case 22 . [0143] When the insulating layer 56 made of nylon is heated, it softens and becomes adhesive. By making use of the adhesiveness of the insulating layer 56 , the molds 85 a - d are stuck and fixed to the insulating layer 56 . Because the molds 85 a - d are also made of nylon, they stick well to the insulating layer 56 . [0144] As shown in FIG. 28 , the front and back edges of the case 22 are provided with the molds 85 a and 85 b , respectively. By making use of the adhesiveness of the insulating layer 56 , the molds 85 a and 85 b are stuck onto the insulating layer 56 to cover the front and back edges of the case 22 . Thus, loose ends of carbon fibers, if any, at the front and back edges of the case 22 are covered up. [0145] Because the molds 85 a and 85 b extend along the front and back edges of the case 22 , they serve as beams, too, reinforcing the case 22 against bending and twisting. [0146] As shown in FIG. 28 , grooves 54 are made in the surfaces of the molds 85 a and 85 b which come in contact with the insulating layer 56 . When the insulating layer 56 is heated and softened and the molds 85 a and 85 b are stuck on the insulating layer 56 , surplus softened, adhesive nylon enters into the grooves 54 . [0147] Thus, the surplus softened, adhesive nylon is prevented from leaking out through the joints between the case 22 and the molds 85 a and 85 b . If the surplus softened, adhesive nylon leaks out, the appearance of the electronic device 1 is spoiled. [0148] Because the case 22 has the right and left side plates, these side plates play the role of the molds 85 a and 85 b. [0149] The opposite of the inside surface of the case 22 in FIG. 19 is a facing, which is the surface of one of the outmost layers 53 a and 53 b . A layer of self-cure resin is formed on the facing. [0150] The layer of self-cure resin is formed by spraying, for example, acrylic or urethane resin with cross-linked structure and high capability of elastic recovery to the facing of the case 22 . [0151] If a flaw or dent is made in the self-cure resin layer on the facing of the case 22 , it exists as a flaw or dent temporarily and then it disappears gradually because of the high capability of elastic recovery of the self-cure resin layer. [0152] The self-cure resin used in the present embodiment is transparent and colorless. It gives luster to the facing of the case 22 made of dull black CFRP (carbon fiber reinforced plastics) to improve the appearance of the case 22 . [0153] The unit consisting of the liquid crystal panel 7 and the inverter circuit board 93 shown in FIG. 21 is fitted in the inside of the case 22 of FIG. 19 . Because the inverter circuit board 93 does not overlap with the liquid crystal panel 7 as shown in FIG. 21 , the display 5 is thin. The thinness of the display 5 as well as the thinness of the body 3 contributes to the thinness of the electronic device 1 . [0154] The liquid crystal panel 7 has a back-light unit including a light source, light-guiding plates, etc. A fluorescent lamp, for example, is used as the light source, which may be built in the top of the liquid crystal panel 7 . [0155] As shown in FIG. 19 , a piece of conductor foil 89 such as copper foil is stuck on the inside surface of the case 22 to earth the liquid crystal panel 7 to the case 22 . [0156] In general, there exists a thin resin film (for example, an epoxy-resin film) on the surface of a base plate made of CFRP; accordingly, the surface of the base plate does not have stable conductivity. As in FIG. 27 , if a piece of copper foil 89 is pressed onto a resin film 127 on the surface of the outermost layer 53 a , the piece of copper foil 89 pushes aside the resin film 127 and sticks to the layer 53 a to secure a stable electric connection between the piece of copper foil 89 and the conductive carbon fibers of the layer 53 a. [0157] As shown in FIG. 22 , a leaf spring 95 is fitted between the piece of copper foil 89 on the inside of the case 22 and a metal bracket 91 a mounted on a metal frame 91 of the liquid crystal panel 7 to electrically connect the liquid crystal panel 7 to the piece of copper foil 89 . The tip of the leaf spring 95 is in elastic contact with the piece of copper foil 89 and the base of the leaf spring 95 is fixed to the metal bracket 91 a by, for example, a screw. [0158] Thus, the liquid crystal panel 7 is electrically stably connected to the case 22 with a large area to protect the liquid crystal panel 7 from external magnetic noises and prevent the magnetic noises generated by the liquid crystal panel 7 from affecting external components and devices. [0159] As shown in FIG. 1 , a frame 24 is fitted to the case 22 housing the liquid crystal panel 7 to expose the screen 70 of the liquid crystal panel 7 . [0160] The hinges “h” to connect the body 3 and the display 5 will next be described below. [0161] When the lower section 27 of FIG. 3 and the upper section 28 of FIG. 17 are combined, the part 42 a of the lower section 27 and the part 74 a of the upper section 28 are combined to become a cylinder of a hinge “h.” One hinge h (the left hinge h in FIGS. 1 and 2 ) is constructed when the cylinder of the case 26 is rotatably connected with the constituent part 87 a of the case 22 shown in FIG. 19 . [0162] On the other hand, when the lower section 27 of FIG. 3 and the upper section 28 of FIG. 17 are combined, the part 42 b of the lower section 27 and the part 74 b of the upper section 28 are combined to become another cylinder. The other hinge h (the right hinge h in FIGS. 1 and 2 ) is constructed when the cylinder of the case 26 is rotatably connected with the constituent part 87 b of the case 22 shown in FIG. 19 . [0163] As shown in FIG. 23 , a hinge fitting 97 is provided on the other hinge h. One end of the hinge fitting 97 is fixed to the cylinder of the case 26 by, for example, a screw. The constituent part of the case 22 receives a cylindrical portion of the hinge fitting 97 , and the case 22 , or the display 5 , is relatively rotatable about the cylindrical portions of the hinge fittings 97 . [0164] Further, as shown in FIG. 23 , a power switch 20 is provided on an edge of the hinge's shaft (a side portion which does not face the other hinge with respect to the longitudinal direction of the axis of the hinge, namely, a side portion on the right in FIG. 23 ). (Also, see FIG. 2 ) [0165] The power switch 20 comprises, as shown in a schematic diagram of FIG. 25 , a pressing operation part 101 , a light-emitting element 121 , a switch 125 , and a contact 123 . [0166] The pressing operation part 101 can be pressed along the longitudinal direction of the axis of the hinge (the direction shown by the arrow in FIG. 25 ). The light-emitting element 121 is placed inside the pressing operation part 101 . The light-emitting element 121 is, for example, a light-emitting diode and is mounted on a surface, which faces the pressing operation part 101 , of the circuit board 103 joined with the pressing operation part 101 . [0167] The switch 125 is mounted on the other side of the circuit board 103 . The contact 123 provided facing the switch 125 is fixed to the constituent part of the case 22 . [0168] As shown in FIG. 2 , the pressing operation part 101 is exposed to the outside. When the pressing operation part 101 is pressed in the direction of the arrow in FIG. 25 by a user's finger and so on, it moves toward the contact 123 together with the circuit board 103 , and the light-emitting element 121 and the switch 125 mounted thereon. [0169] When the switch 125 is pressed touching the contact 123 , the power is turned off when the power of the electronic device 1 is on and the power is turned on when the power of the electronic device 1 is off. [0170] When the pressing operation part 101 is pressed sideways by the user's finger, the direction of the movement tends to be inclined compared to when it is pressed downward. To cope with such a problem, the surface of the switch 125 which meets the contact 123 is curved. Therefore, in spite of a little inclination, the contact and the switch 125 can meet stably (for example, compared to when the surface is flat, the contact area can be larger) and the power can be turned on or off reliably. [0171] Incidentally, the pressing operation part 101 has substantially a round shape, and is disposed so that the rotation axis of the hinge will pierce substantially the center of the round pressing operation part 101 . Consequently, when the power switch is pressed in the direction of the rotation axis of the hinge, the power supply is turned on or off. Since the switch 125 is pressed in the direction of the rotation axis of the hinge, the pressing operation part 101 that is large for the thickness of the display 5 or the body 3 can be employed. Consequently, the power switch 20 is reliably manipulated. [0172] According to the present embodiment, the pressing operation part 101 that is large for the thickness of the display 5 or body 3 is adopted. As long as the pressing operation part 101 that is pressed in the direction of the rotation axis of the hinge is adopted, the pressing operation part 101 (switch or button) that is larger than a switch (button) to be formed in the lateral side of the case can be formed because of the thicknesses of the cases 22 , 24 , 27 , and 28 that determine the shapes of the display 5 and body 3 respectively. [0173] The usage of the space in the hinge is not limited to the power switch as it is in the present embodiment. Alternatively, a switch (button) for any purpose other than the purpose of power supply may be formed. For example, when electronic device includes an imaging means that has a CCD or the like, the space in the hinge may be used to form a shutter button required for producing still images or an imaging start/stop button required for producing a motion picture. [0174] Further, if all or a part (for example, a ring portion of the outer edge) of the portion of the pressing operation part 101 exposed to the outside is formed as a light-transmission part made of transparent resin material, the light from the light-emitting element 121 can be guided to the outside through such a light-transmission part. Accordingly, when the power is on, for example, a red light can be turned on to have a user confirm its state visually. Alternatively, when in a power-saving standby state, a green light can be turned on and off to have the user confirm its state visually. [0175] The light transmission part of the pressing operation part 101 is always exposed to the outside regardless of the electronic device 1 being opened or closed. Therefore, even if the display 5 is closed while the power is on, the state can be checked by the light visible through the light transmission part. [0176] Also, when carrying the electronic device 1 in a bag or so with the display 5 closed, the pressing operation part 101 may be pressed by an article in the bag. Accordingly, in the present embodiment, as in FIG. 23 , a closed-state detecting switch 105 is provided on the constituent part of the case 22 , and a closed-state detecting contact 106 is provided on the hinge fitting 97 as a single piece. [0177] When the display 5 is closed onto the body 3 by the relative rotation of the constituent part of the case 22 and the hinge fitting 97 , the closed-state detecting switch and the closed-state detecting contact 106 meet, turning on the closed-state detecting switch 105 . The closed-state detecting switch 105 is kept turned on while the display 5 is closed onto the body 3 . [0178] Accordingly, when the closed-state detecting switch 105 is on, that is, when the display is closed, the electronic device 1 can be prevented from being turned on even if the pressing operation part 10 is pressed. Alternatively, when it is closed while the power is on and the closed-state detecting switch 105 is turned on, it becomes possible to automatically turn the power off or to send the electronic device 1 into a power-saving standby state. [0179] Incidentally, a control mode is not limited to the mode of controlling the power supply according to whether the display is open or closed, but any other control mode may be adopted. [0180] For example, when electronic device has an imaging means that includes a CCD, the action of a shutter button required for producing still images or an imaging start/stop button required for producing a motion picture may be controlled based on whether the case is open or closed. For example, control is extended so that when the case is closed, even if the button is pressed, a still image or a motion picture will not be produced. [0181] Incidentally, the means for detecting whether the display 5 is open or closed is not limited to the one employed in the present embodiment, but any other means will do. For example, a magnetic body included in the display 5 , and a Hall sensor that is located in a region in the body 3 in which the Hall sensor is opposed to the magnetic body and that detects a magnetic field strength may be used to detect whether the display is open or closed. [0182] Further, as in FIG. 24 , a connector 19 for an AC adapter is provided on the edge (side portion on the left in FIG. 24 ) of the shaft of the hinge opposite the hinge in which the power switch 20 is provided (Also, see FIG. 1 ). A socket for the connector 19 is always exposed to the outside regardless of the opened and closed state of the electronic device 1 . [0183] Moreover, the connector 19 is disposed so that the rotation axis of the hinge and the axis of the connector 19 will be aligned with each other. [0184] Since the port of the connector 19 opens in the direction of the rotation axis of the hinge, the connector that is large for the thickness of the display 5 or body 3 can be employed. [0185] According to the present embodiment, the connector 19 that is large for the thickness of the display 5 or body 3 is employed. As long as the port of the connector opens in the direction of the rotation axis of the hinge, a connector larger than the one formed in the lateral side of any of the cases 22 , 24 , 27 , and 28 , which determine the shapes of the display 5 and body 3 respectively, can be formed because of the thicknesses of the cases. [0186] The usage of the space in the hinge is not limited to the connector for connection of an AC adaptor as it is in the present embodiment. A connector for any purpose other than the purpose of power supply may be formed. For example, a connector for connection of a headphone may be formed. Moreover, the shape of the port of the connector is not limited to a round but may be a rectangle. For example, a connector for plugging in of a universal serial bus (USB) 2.0 may be formed. [0187] As in FIG. 24 , a cable 112 for connecting the connector 19 with the motherboard 30 of the body 3 is not directed straight from the connection with the connector 19 to the side of the body 3 (lower position in FIG. 24 ). On the contrary, the cable 112 detours around the area near the connection with the connector 19 so that it forms a loop on the side of the display 5 and is drawn to the side of the body 3 . [0188] The detouring portion of the cable 112 forms a loop being guided by a boss 114 erected inside the case 22 and guide members 118 , 119 a , 119 b. [0189] Accordingly, even if opening and closing of the display 5 away from and onto the body 3 are repeated, the connection (soldered, for example) to the connector 19 of the cable 112 is prevented from receiving a concentrated excessive load such as twisting and pulling, thereby a break in the cable being prevented. [0190] Further, the guide members 119 a and 119 b restrict the rising of the detouring portion of the cable 112 from the inside surface of the case 22 so that the looped detouring portion can be held stably. [0191] Further, the previously described power switch 20 shown in FIG. 23 is configured such that a cable (not shown) connected to the connector 110 via the flexible wiring board 108 formed on the inside surface of the case 22 is drawn to the side of the body 3 . Therefore, again, the cable is not drawn directly from the power switch 20 to the body 3 . This is because the previously described inverter circuit board 93 is not provided on the inside surface of the case 22 on this side and there is enough space for arranging the above flexible wiring board 108 and the connector 110 . [0192] As described above, the power switch 20 and the connector 19 are provided on the edge portion of the shaft of the hinge, which has not been used at all, namely, a dead space. Therefore, components of the body 3 and the display 5 can be positioned more freely. By suitably arranging those components, the body 3 and the display 5 can be made thinner as described above. Further, since the power switch 20 is positioned away from the keyboard 11 and other operation buttons 15 a - 15 c (see FIG. 1 ), it is prevented from being mistakenly pressed, ensuring reliable operation. Thus, mistakes such as turning the power off while the device is in use can be avoided. [0193] The embodiment has been described by taking for instance the electronic device including the display 5 and body 3 that can be freely turned on the hinges to be open or closed. The present invention can be adapted to any other type of electronic device as long as a first case and a second case can be freely turned on hinges to be open or closed. For example, electronic device including two displays that can be freely turned on hinges to be open or closed will do. [0194] Moreover, according to the aforesaid embodiment, the hinges are formed on the edge of the case of electronic device away from a user under the normal specifications. Alternatively, electronic device whose right and left cases are turned on hinges to be open or closed will do. [0195] Functions such as left-clicking, right-clicking, and scrolling are assigned to the three operation buttons 15 a - c disposed on the front edge about the center between the right and left sides of the body 3 . [0196] Also, as shown in FIGS. 1 and 2 , there is a battery 9 provided between the hinges h. [0197] Further, as shown in FIGS. 1 and 2 , a bottom surface of the lower section 27 is not flat, and the rear end on the side of the hinges h is curved (so that it rises a little from the surface where the electronic device is placed). Compared to the bottom surface of the lower section 27 being flat, this structure reinforces the lower section 27 against bending and twisting. [0198] Also, as shown in FIG. 29 , a stopper 130 is provided on a periphery of each hinge h facing backward of the electronic device 1 . when the display 5 is opened, the display 5 is prevented from opening further by the lower edge of the display 5 meeting the stopper 130 . For example, in the present embodiment, the angle of opening (an angle formed by the body 3 and the display 5 ) is restricted to 135°. [0199] Further, as shown in FIGS. 2 and 30 , tapered portions 68 and 69 are formed respectively at the front edges of the case 26 and the case 22 facing with each other so that the front edges make a V-shape when the display 5 is closed onto the body 3 . [0200] The tapered portion 68 is inclined upward toward the front, and the tapered portion 69 is inclined downward toward the front. The distance between the tapered portions 68 and 69 in a closed state, namely, when the case 26 and the case 22 are closed, gradually increases toward the front. [0201] With such a structure, even if the body 3 and the display 5 are very thin like the ones in the present embodiment, the front edge of the display 5 can easily be lifted from the body 3 staying where it is by putting a finger in a V-shaped area between the tapered portions 68 , and hooking the tapered portion 68 of the case 22 with a fingertip. [0202] Further, as shown in FIGS. 1 and 2 , various indicator lamps 17 a - 17 c provided in the front edge of the body 3 extend to the downwardly inclined area of the front edge. Therefore, even when the display 5 is closed as in FIG. 2 , the above various indicator lamps 17 a - 17 c are visible to the user. [0203] Although the invention has been described in its preferred form, it is to be understood that the invention is not limited to the specific embodiments thereof and various changes and modifications may be made without departing from the sprit and the scope of the invention. [0204] Instead of the PC card slot of the body 3 , any other semiconductor-memory card slot may be provided. [0205] Further, the heat-transmitting sheets 72 and 47 may be stuck to the inside of the upper section 28 and an entire surface of the inside of the lower section 27 , respectively.

A power switch and connector that are conventionally included in a body are formed in spaces created at the outer ends of the shafts of hinges other than the body and a display, whereby the body is thinned. Electronic device comprises a body, a display, and a hinge that joins the body and display so that they can be freely opened or closed. A power switch is formed at an end of the shaft of the hinge. Furthermore, the electronic device comprises the body, the display, and another hinge that joins the body and display so that they can be freely opened or closed. A port of a connector opens at an end of the shaft of the hinge.

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application is a divisional of copending U.S. utility application entitled, “Higher Picture Rate HD Encoding and Transmission with Legacy HD Backward Compatibility,” having Ser. No. 11/132,060, filed May 18, 2005, which is entirely incorporated herein by reference. TECHNICAL FIELD [0002] The present invention relates to digital television and, more specifically to receivers with different capabilities for receiving, processing and displaying the same emission of a compressed video signal, each receiver providing one in a plurality of picture formats according to its respective capability. BACKGROUND OF THE INVENTION [0003] There are many different digital television compressed video picture formats, some of which are HD. HDTV currently has the highest digital television spatial resolution available. The picture formats currently used in HDTV are 1280×720 pixels progressive, 1920×1080 pixels interlaced, and 1920×1080 pixels progressive. These picture formats are more commonly referred to as 720P, 1080i and 1080P, respectively. The 1080i format, which comprises of interlaced pictures, each picture or frame being two fields, shows 30 frames per second and it is deemed as the MPEG-2 video format requiring the most severe consumption of processing resources. The 1080P format shows 60 frames per second, each frame being a progressive picture, and results in a doubling of the most severe consumption of processing resources. A receiver capable of processing a maximum of 1080i-60 is also capable of processing a maximum 1080P-30. However, broadcasters intend to introduce 1080P-60 emissions and CE manufacturers intend to provide HDTVs and HDTV monitors capable of rendering 1080P-60, in the near future. 1080P-60 includes twice as much picture data as either 1080i-60 or 1080P-30. Dual carrying channels or programs as 1080P-60 and 1080i-60 would not be an acceptable solution because it triples the channel consumption of a single 1080i-60 transmission. [0004] Therefore, there is a need for encoding 1080P-60 video for transmission in a way that facilitates the superior picture quality benefits of a 1080P-60 signal to 1080P-60 capable receivers while simultaneously enabling legacy 1080i-60 capable receivers to fulfill the equivalent of a 1080P-30 signal from the transmitted 1080P-60 signal. BRIEF DESCRIPTION OF THE DRAWINGS [0005] FIG. 1 is a high-level block diagram depicting a non-limiting example of a subscriber television system. [0006] FIG. 2 is a block diagram of a DHCT in accordance with one embodiment of the present invention. [0007] FIG. 3 illustrates program specific information (PSI) of a program having elementary streams including encoded video streams which may be combined to form a single video stream encoded as 1080P-60. [0008] FIG. 4A illustrates first and second video streams in display order. [0009] FIG. 4B illustrates pictures according to picture types in display order. [0010] FIG. 4C illustrates transmission order of the pictures in display order of FIG. 2B . DETAILED DESCRIPTION [0011] The present invention will be described more fully hereinafter with reference to the accompanying drawings in which like numerals represent like elements throughout the several figures, and in which an exemplary embodiment of the invention is shown. This invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, the embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The present invention is described more fully hereinbelow. [0012] It is noted that “picture” is used throughout this specification as one from a sequence of pictures that constitutes video, or digital video, in one of any of a plurality of forms. Furthermore, in this specification a “frame” means a picture, either as a full progressive picture or in reference to a whole instance of a full frame comprising both fields of an interlaced picture. Video Decoder in Receiver [0013] FIG. 1 is a block diagram depicting a non-limiting example of a subscriber television system (STS) 100 . In this example, the STS 100 includes a headend 110 and a DHCT 200 that are coupled via a network 130 . The DHCT 200 is typically situated at a user's residence or place of business and may be a stand-alone unit or integrated into another device such as, for example, the display device 140 or a personal computer (not shown). The DHCT 200 receives signals (video, audio and/or other data) including, for example, MPEG-2 streams, among others, from the headend 110 through the network 130 and provides any reverse information to the headend 110 through the network 130 . The network 130 may be any suitable means for communicating television services data including, for example, a cable television network or a satellite television network, among others. The headend 110 may include one or more server devices (not shown) for providing video, audio, and textual data to client devices such as DHCT 200 . Television services are provided via the display device 140 which is typically a television set. However, the display device 140 may also be any other device capable of displaying video images including, for example, a computer monitor. [0014] FIG. 2 is a block diagram illustrating selected components of a DHCT 200 in accordance with one embodiment of the present invention. It will be understood that the DHCT 200 shown in FIG. 2 is merely illustrative and should not be construed as implying any limitations upon the scope of the preferred embodiments of the invention. For example, in another embodiment, the DHCT 200 may have fewer, additional, and/or different components than illustrated in FIG. 2 . A DHCT 200 is typically situated at a user's residence or place of business and may be a stand alone unit or integrated into another device such as, for example, a television set or a personal computer. The DHCT 200 preferably includes a communications interface 242 for receiving signals (video, audio and/or other data) from the headend 110 through the network 130 ( FIG. 1 ) and for providing any reverse information to the headend 110 . [0015] DHCT 200 is referred to as a receiver such as receiver 200 throughout this specification. The DHCT 200 further preferably includes at least one processor 244 for controlling operations of the DHCT 200 , an output system 248 for driving the television display 140 , and a tuner system 245 for tuning to a particular television channel or frequency and for sending and receiving various types of data to/from the headend 110 . The DHCT 200 may, in another embodiment, include multiple tuners for receiving downloaded (or transmitted) data. Tuner system 245 can select from a plurality of transmission signals provided by the subscriber television system 100 , including a 1080P-60 program. Tuner system 245 enables the DHCT 200 to tune to downstream media and data transmissions, thereby allowing a user to receive digital media content such as a 1080P-60 program via the subscriber television system. The tuner system 245 includes, in one implementation, an out-of-band tuner for bi-directional quadrature phase shift keying (QPSK) data communication and a quadrature amplitude modulation (QAM) tuner (in band) for receiving television signals. Additionally, a user command interface 246 receives externally-generated user inputs or commands from an input device such as, for example, a remote control. User inputs could be alternatively received via communication port 274 . [0016] The DHCT 200 may include one or more wireless or wired interfaces, also called communication ports 274 , for receiving and/or transmitting data to other devices. For instance, the DHCT 200 may feature USB (Universal Serial Bus), Ethernet, IEEE-1394, serial, and/or parallel ports, etc. DHCT 200 may also include an analog video input port for receiving analog video signals. User input may be provided via an input device such as, for example, a hand-held remote control device or a keyboard. [0017] The DHCT 200 includes signal processing system 214 , which comprises a demodulating system 213 and a transport demultiplexing and parsing system 215 (herein demultiplexing system) for processing broadcast media content and/or data. One or more of the components of the signal processing system 214 can be implemented with software, a combination of software and hardware, or preferably in hardware. Demodulating system 213 comprises functionality for demodulating analog or digital transmission signals. For instance, demodulating system 213 can demodulate a digital transmission signal in a carrier frequency that was modulated, among others, as a QAM-modulated signal. When tuned to a carrier frequency corresponding to an analog TV signal, demultiplexing system 215 is bypassed and the demodulated analog TV signal that is output by demodulating system 213 is instead routed to analog video decoder 216 . Analog video decoder 216 converts the analog TV signal into a sequence of digitized pictures and their respective digitized audio. The analog TV decoder 216 and other analog video signal components may not exist in receivers or DHCTs that do not process analog video or TV channels. [0018] A compression engine in the headend processes a sequence of 1080P-60 pictures and associated digitized audio and converts them into compressed video and audio streams, respectively. The compressed video and audio streams are produced in accordance with the syntax and semantics of a designated audio and video coding method, such as, for example, MPEG-2, so that they can be interpreted by video decoder 223 and audio decoder 225 for decompression and reconstruction after transmission of the two video streams corresponding to the 1080P-60 compressed signal. Each compressed stream consists of a sequence of data packets containing a header and a payload. Each header contains a unique packet identification code, or packet_identifier (PID) as is the casein MPEG-2 Transport specification, associated with the respective compressed stream. The compression engine or a multiplexer at the headend multiplexes the first and second video streams into a transport stream, such as an MPEG-2 transport stream. [0019] Video decoder 223 may be capable of decoding a first compressed video stream encoded according to a first video specification and a second compressed video stream encoded according to a second video specification that is different than the first video specification. Video decoder 223 may comprise of two different video decoders, each respectively designated to decode a compressed video stream according to the respective video specification. [0020] Parsing capabilities 215 within signal processing 214 allow for interpretation of sequence and picture headers. The packetized compressed streams can be output by signal processing 214 and presented as input to media engine 222 for decompression by video decoder 223 and audio decoder 225 for subsequent output to the display device 140 ( FIG. 1 ). [0021] Demultiplexing system 215 can include MPEG-2 transport demultiplexing. When tuned to carrier frequencies carrying a digital transmission signal, demultiplexing system 215 enables the separation of packets of data, corresponding to the desired video streams, for further processing. Concurrently, demultiplexing system 215 precludes further processing of packets in the multiplexed transport stream that are irrelevant or not desired such as, for example in a 1080i-60 capable receiver, packets of data corresponding to the second video stream of the 1080P-60 program. [0022] The components of signal processing system 214 are preferably capable of QAM demodulation, forward error correction, demultiplexing MPEG-2 transport streams, and parsing packetized elementary streams and elementary streams. The signal processing system 214 further communicates with processor 244 via interrupt and messaging capabilities of DHCT 200 . [0023] The components of signal processing system 214 are further capable of performing PID filtering to reject packetized data associated with programs or services that are not requested by a user or unauthorized to DHCT 200 , such rejection being performed according to the PID value of the packetized streams. PID filtering is performed according to values for the filters under the control of processor 244 . PID filtering allows for one or more desired and authorized programs and/or services to penetrate into DHCT 200 for processing and presentation. PID filtering is further effected to allow one or more desired packetized streams corresponding to a program (e.g., a 1080P — 60 program) to penetrate DHCT 200 for processing, while simultaneously rejecting one or more different packetized stream also corresponding to the same program. Processor 244 determines values for one or more PIDS to allow to penetrate, or to reject, from received information such as tables carrying PID values as described later in this specification. In an alternate embodiment, undesirable video streams of a program are allowed to penetrate into DHCT 200 but disregarded by video decoder 223 . [0024] A compressed video stream corresponding to a tuned carrier frequency carrying a digital transmission signal can be output as a transport stream by signal processing 214 and presented as input for storage in storage device 273 via interface 275 . The packetized compressed streams can be also output by signal processing system 214 and presented as input to media engine 222 for decompression by the video decoder 223 and audio decoder 225 . [0025] One having ordinary skill in the art will appreciate that signal processing system 214 may include other components not shown, including memory, decryptors, samplers, digitizers (e.g. analog-to-digital converters), and multiplexers, among others. Further, other embodiments will be understood, by those having ordinary skill in the art, to be within the scope of the preferred embodiments of the present invention. For example, analog signals (e.g., NTSC) may bypass one or more elements of the signal processing system 214 and may be forwarded directly to the output system 248 . Outputs presented at corresponding next-stage inputs for the aforementioned signal processing flow may be connected via accessible memory 252 in which an outputting device stores the output data and from which an inputting device retrieves it. Outputting and inputting devices may include analog video decoder 216 , media engine 222 , signal processing system 214 , and components or sub-components thereof. It will be understood by those having ordinary skill in the art that components of signal processing system 214 can be spatially located in different areas of the DHCT 200 . [0026] In one embodiment of the invention, a first and second tuners and respective first and second demodulating systems 213 , demultiplexing systems 215 , and signal processing systems 214 may simultaneously receive and process the first and second video streams of a 1080P-60 program, respectively. Alternatively, a single demodulating system 213 , a single demultiplexing system 215 , and a single signal processing system 214 , each with sufficient processing capabilities may be used to process the first and second video streams in a 1080P-60 capable receiver. [0027] The DHCT 200 may include at least one storage device 273 for storing video streams received by the DHCT 200 . A PVR application 277 , in cooperation with the operating system 253 and the device driver 211 , effects, among other functions, read and/or write operations to the storage device 273 . The device driver 211 is a software module preferably resident in the operating system 253 . The device driver 211 , under management of the operating system 253 , communicates with the storage device controller 279 to provide the operating instructions for the storage device 273 . Storage device 273 could be internal to DHCT 200 , coupled to a common bus 205 through a communication interface 275 . [0028] Received first and second video streams are deposited transferred to DRAM 252 , and then processed for playback according to mechanisms that would be understood by those having ordinary skill in the art. In some embodiments, the video streams are retrieved and routed from the hard disk 201 to the digital video decoder 223 and digital audio decoder 225 simultaneously, and then further processed for subsequent presentation via the display device 140 . [0029] Compressed pictures in the second video stream may be compressed independent of reconstructed pictures in the first video stream. On the other hand, an aspect of the invention is that pictures in the second video stream, although compressed according to a second video specification that is different to the first video specification, can depend on decompressed and reconstructed pictures in the first video stream for their own decompression and reconstruction. [0030] Examples of dependent pictures are predicted pictures that reference at most one picture (from a set of at least one reconstructed picture) for each of its sub-blocks or macroblocks to effect its own reconstruction. That is, predicted pictures in the second video stream, can possibly depend one or more referenced pictures in the first video stream. [0031] Bi-predicted pictures (B-pictures) can reference at most two pictures from a set of reconstructed pictures for reconstruction of each of its sub-blocks or macroblocks to effect their own reconstruction. [0032] In one embodiment, pictures in the second video stream reference decompressed and reconstructed pictures (i.e., reference pictures) from the first video stream. In another embodiment, pictures in the second video stream employ reference pictures from both the first and second video streams. In yet another embodiment, a first type of picture in the second video stream references decompressed pictures from the second video stream and a second type of picture references decompressed pictures from the first video stream. [0000] Enabling Receivers with Different Capabilities [0033] The present invention includes several methods based on two separate video streams assigned to a program rather than a single stream with inherent built-in temporal scalability. Existing receivers capable of processing 1080i-60 video streams today would be deemed “legacy HD receivers” at the time that broadcasters start emissions of 1080P-60 programs. If a 1080P-60 program was transmitted without the advantage of this invention the “then” legacy HD receivers would not know how to process a 1080P-60 video stream, nor be capable of parsing the video stream to extract a 1080P-30 signal from the received 1080P-60. The legacy HD receivers were not designed to identify and discard pictures from a single 1080P-60 video stream. Furthermore, 1080P-60 in the standard bodies is specified for a 1080P-60 receiver without backward compatibility to 1080i-60 receivers. [0034] This invention enables 1080i-60 receivers to process the portion of the 1080P-60 program corresponding to a first video stream and reject a complementary second video stream based on PID filtering. Thus, by processing the first video stream, a 1080i-60 receiver provides a portion of the 1080P-60 program that is equivalent to 1080P-30. The invention is equally applicable, for example, to 1080P-50, assigning two separate video streams to a program. Future 1080P50-capable receivers process the 1080P-50 video from the two separate video streams according to the invention, while legacy 1080i-50-capable receivers process a 1080P-25 portion of the 1080P-50 video program. [0035] Hereinafter, 1080P-60 is used for simplicity to refer to a picture sequence with twice the picture rate of a progressive 1080P-30 picture sequence, or to a picture sequence with twice the amount of picture elements as an interlaced picture sequence displayed as fields rather than full frames. However, it should be understood that the invention is applicable to any pair of video formats with the same picture spatial resolution, in which a first video format has twice the “picture rate” of the second. The invention is also applicable to any pair of video formats with the same picture spatial resolution, in which a first video format has “progressive picture rate” and the second has an “interlaced” or field picture rate, the first video format resulting in twice the number of processed or displayed pixels per second. The invention is further applicable to any two video formats in which the first video format's picture rate is an integer number times that of the second video format or in which the number of pixels of a first video format divided by the number of pixels of a second video format is an integer number. Stream Types and Unique PIDs [0036] The MPEG-2 Transport specification referred to in this invention is described in the two documents: ISO/IEC 13818-1:2000 (E), International Standard, Information technology—Generic coding of moving pictures and associated audio information: Systems, and ISO/IEC 13818-1/Amd. 3: 2003 Amendment 3: Transport of AVC video data over ITU-T Rec. H.222.0 |ISO/IEC 13818-1 streams. [0037] In accordance with MPEG-2 Transport syntax, a multiplexed transport carries Program Specific Information (PSI) that includes the Program Association Table (PAT) and the Program Map Table (PMT). Information required to identify and extract a PMT from the multiplexed transport stream is transmitted in the PAT. The PAT carries the program number and packet identifier (PID) corresponding to each of a plurality of programs, at least one such program's video being transmitted as encoded 1080P-60 video according to the invention. [0038] As shown in the FIG. 3 , the PMT corresponding to a 1080P-60 program carries two video streams, each uniquely identified by a corresponding PID. The first video stream in the PMT has a unique corresponding PID 341 and the second video stream has its unique corresponding PID 342 , for example. Likewise, the first and second video streams of the 1080P-60 program have corresponding stream type values. A stream type is typically a byte. The stream type value for the first and second video streams are video_type1 and video_type2, respectively. [0039] In one embodiment, the stream type value, video_type1 equals video_type2, therefore, both video streams are encoded according to the syntax and semantics of the same video specification (e.g., both as MPEG-2 video or as MPEG-4 AVC). A receiver is then able to identify and differentiate between the first video stream and the second video stream by their PID values and the relationship of the two PID values. For example, the lower PID value of video_type1 would be associated with the first video stream. However, legacy HD receivers would not be able to incorporate such a processing step as a feature. However, there may be two types of legacy receivers. During a first era, legacy receivers may be HD receivers that are capable of processing a first video stream encoded according to the MPEG-2 video specification described in ISO/IEC 13818-2:2000 (E), International Standard, Information technology—Generic coding of moving pictures and associated audio information: Video. The second video stream would likely be encoded with a video specification that provides superior compression performance, for example, MPEG-4 AVC as described by the three documents: ISO/IEC 14496-10 (ITU-T H.264), International Standard (2003), Advanced video coding for generic audiovisual services; ISO/IEC 14496-10/Cor. 1: 2004 Technical Corrigendum 1; and ISO/IEC 14496-10/Amd. 1,2004, Advanced Video Coding AMENDMENT 1: AVC fidelity range extensions. A second era, on the other hand, may comprise legacy HD receivers that are capable of processing 1080i-60 video encoded according to the MPEG-4 AVC specification. Because the latter legacy receivers have yet to be deployed, these receivers could be designed to support identification of the first video stream in a multiple video stream program from the lowest PID value corresponding to video_type1 in the PMT. Alternatively, the first video entry in the PMT table, regardless of its PID value, would be considered the first video stream. [0040] In another alternate embodiment, the streams are encoded according to different video specifications and the values of video_type1 and video_type2 in the PMT differ. For example, the first video stream would be encoded and identified as MPEG-2 video in the PMT by a video_type1 value that corresponds to MPEG-2 video. The second video stream would be encoded with MPEG-4 AVC and identified by a video_type2 value corresponding to MPEG-4 AVC. [0041] In yet another alternate embodiment, video_type2 corresponds to a stream type specifically designated to specify the complementary video stream (i.e, the second video stream of a 1080P-60 program). Both video streams could be encoded according to the syntax and semantics of the same video specification (e.g, with MPEG-4 AVC) or with different video specifications. Thus, while the values of video_type1 and video_type2 are different in the PMT table for a 1080P-60 program, both video streams composing the 1080P-60 program could adhere to the same video specification. Thus, video_jype 1 's value identifies the video specification used to encode the first video stream, but video_type2's value identifies both: [0042] (1) the video stream that corresponds to the second video stream of the 1080P-60 program, and [0043] (2) the video specification (or video coding format) used to encode the second video stream. [0044] A first video_type2 value then corresponds to a stream type associated with the second stream of a 1080P-60 program that is encoded according to the MPEG-2 video specification. A second video_type2 value corresponds to a stream type associated with the second stream of a 1080P-60 program that is encoded according to the MPEG-4 AVC specification. Likewise, other video_type2 values can correspond to respective stream types, each associated with the second stream of a 1080P-60 program and encoded according to a respective video coding specification. [0045] In yet another novel aspect of the invention, when video_type2 does not equal video_type1 and their values signify different video specifications, pictures in the second stream can still use reconstructed pictures from the first video stream as reference pictures. Transmission Order of Pictures [0046] Encoded pictures in the first and second video streams are multiplexed in the transport multiplex according to a defined sequence that allows a single video decoder in a 1080P-60 receiver to receive and decode the pictures sequentially as if the pictures were transmitted in a single video stream. However, because they are two separate video streams, a 1080i-60 receiver can reject transport packets belonging to the second video stream and allow video packets corresponding to the first video stream to penetrate into its memory to process a portion equal to 1080P-30 video. Encoded pictures in the first video stream are transmitted in transmission order, adhering to the timing requirement and bit-buffer management policies required for a decoder to process the first video stream as a 1080P-30 encoded video signal. [0047] In one embodiment of the invention, FIG. 4A depicts the first and second video streams in display order. P represents a picture and not a type of picture. Pi is the ith picture in display order. In a 1080P-60 receiver, the blank squares represent gaps of when the picture being displayed is from the complementary video stream. The width of a blank square is one “picture display” time. Non-blank squares represent the time interval in which the corresponding picture is being displayed. [0048] Still referring to FIG. 4A , in a 1080i-60 receiver, a 1080P-30 picture corresponding to the first video stream is displayed and the width of two squares represents the picture display time. Video stream 1 is specified as 30 Hertz in alternating 60 Hertz intervals that correspond to even integers. Video stream 2 is specified as 30 Hertz in alternating 60 Hertz intervals that correspond to odd integers. [0049] FIG. 4B depicts pictures according to picture types in display order. Ni signifies the ith Picture in display order, where N is the type of picture designated by the letter I, P or B. In one embodiment, all the pictures in video stream 2 are B pictures and the 1080P-60 receiver uses decoded pictures from video stream 1 as reference pictures to reconstruct the B pictures. [0050] FIG. 4C corresponds to the transmission order of the pictures in display order in FIG. 4B . Each picture is transmitted (and thus received by the receiver) at least one 60 Hz interval prior to its designated display time. I pictures are displayed six 60 Hz interval after being received and decoded. I pictures are thus transmitted at least seven 60 Hz intervals prior to its corresponding display time. The arrows from FIG. 4C to FIG. 4B reflect the relationship of the pictures' transmission order to their display order. [0051] Blank squares in FIG. 4C represent gaps when no picture data is transmitted for the respective video stream. The width of a blank square can be approximately one “picture display” time. Non-blank squares represent the time interval in which the corresponding picture is transmitted. One or more smaller transmission gaps of no data transmission may exist within the time interval in which a picture is transmitted. In essence, video stream 1 and video stream 2 are multiplexed at the emission point in a way to effect the transmission order reflected in FIG. 4C and transmission time relationship depicted in FIG. 4C . Bit-Buffer Management [0052] A sequence of video pictures is presented at an encoder for compression and production of a compressed 1080P-60 program. Every other picture is referred as an N picture and every subsequent picture as an N+1 picture. The sequence of all the N pictures is the first video stream of the 1080P-60 program and the sequence all the N+1 pictures is the second video stream. [0053] A video encoder produces the first video stream according to a first video specification (e.g., MPEG-2 video) and the second video stream according to a second video specification (e.g., MPEG-4 AVC). In one embodiment the second video specification is different than the first video specification. In an alternate embodiment, the first and second video specifications are the same (e.g., MPEG-4 AVC). [0054] The video encoder produces compressed pictures for the first video stream by depositing the compressed pictures into a first bit-buffer in memory, such memory being coupled to the encoder. Depositing of compressed pictures into the first bit-buffer is according to the buffer management policy (or policies) of the first video specification. The first bit-buffer is read for transmission by the video encoder in one embodiment. In an alternate embodiment, a multiplexer or transmitter reads the compressed pictures out of the first bit-buffer. The read potions of the first bit buffer are packetized and transmitted according to a transport stream specifications such as MPEG-2 transport. [0055] Furthermore, the video encoder, the multiplexer, or the transmitter, or the entity performing the first bit-buffer reading and packetization of the compressed pictures, prepends a first PID to packets belonging to the first video stream. The packetized first video stream is then transmitted via a first transmission channel. [0056] Similarly, the second video stream is produced by the video encoder and deposited into the first bit buffer. The second video stream is read from the first bit-buffer by the entity performing the packetization, and the entity prepends a second PID to packets belonging to the second video stream, and the transport packets are transmitted via a first transmission channel. [0057] In an alternate embodiment, the second video stream is produced by the video encoder and deposited into a second bit buffer. The entity performing the packetization reads the second video stream from the second bit buffer and prepends the second PID to packets belonging to the second video stream. The packetized second video stream is then transmitted via a first transmission channel. [0058] Both first and second video streams are packetized according to a transport stream specification, such as MPEG-2 Transport. Packets belonging to the second video stream are thus identifiable by a 1080P-60 capable receiver and become capable of being rejected by a receiver that is not capable of processing 1080P-60 programs. [0059] The bit buffer management policies of depositing compressed picture data into the first and/or second bit-buffers and reading (or drawing) compressed-picture data from the first and/or second bit-buffers, are according to the first video specification. These operations may be further in accordance with bit-buffer management policies of the transport stream specification. Furthermore, the bit-buffer management policies implemented on the one or two bit-buffers may be according to the second video specification rather than the first video specification. In one embodiment, the first video stream's compressed data in the bit-buffer is managed according to both: the bit buffer management policies of the first video specification and the transport stream specification, while the second video stream's compressed data in the applicable bit-buffer is managed according to the bit buffer management policies of the second video specification as well as the transport stream specification. [0060] The bit-buffer management policies described above are applicable at the emission or transmission point in the network, such as by the encoder and the entity producing the multiplexing and/or transmission. Bit-buffer management policies, consistent with the actual implementation at the emission or transmission point, are applicable at the receiver to process the one or more received video streams of a 1080P-60 program. The bit-buffer management policy implemented at the emission or transmission point may be provided to the receiver a priori for each program (e.g., with metadata) or according to an agreed one of the alternatives described above that is employed indefinitely. [0000] Enabling More than Two Receivers with Different Respective Processing Capabilities [0061] In an alternate embodiment, the video encoder constitutes two video encoders, a first video encoder producing the first video stream according to the first video specification, and a second video encoder producing the second video stream, which is interspersed for transmission in the transmission channel according to the pockets of “no data” transmission of video stream 1 (as shown in FIG. 4C ). The second video encoder further producing the second video stream according to the second video specification. [0062] In yet another embodiment, the process of alternating transmission of compressed pictures corresponding to the first video stream and compressed pictures corresponding to the second video stream, results in transmission of a first set of consecutive compressed pictures from different the first video stream when it is the turn to transmit the first video stream, or a second set of consecutive compressed pictures from different the second video stream when it is the turn to transmit the second video stream. For instance, instead of alternating between one compressed picture from the first video stream and one from the second video stream, two consecutive compressed pictures from the second video stream may be transmitted after each transmission of a single compressed picture of the first video stream. Thus, a 1080P-90 Hertz program can be facilitated to 1080P-90 receivers and a 1080P-30 portion of the 1080P-90 program to 1080P-30 receivers. Furthermore, by packetizing every second compressed picture in the second video stream with a third PID value that is different than the first and second PIDs, three corresponding versions of the compressed 1080P-90 program are facilitated respectively to a 1080P-30 receiver, a 1080P-60 receiver, and a 1080P-90 receiver, the latter being able to receive and fulfill the full benefits of the 1080P-90 program. [0063] In yet another embodiment, the number of consecutive compressed pictures that is transmitted from the first video stream may be grater than one. For instance, if two consecutive compressed pictures from the first video stream are transmitted and three compressed pictures from the second video stream are transmitted after transmission the two from the first video stream, a number of receivers with different processing capabilities may be enabled. If two different PID values are employed, a 1080P-50 receiver will receive a 1080P-50 Program and a 1080P-20 receiver will receive a 1080P-20 corresponding portion. However, if five different PID values are used for the 1080P-50 program, five receivers, each with different processing capability will be capable of receiving a portion of the 1080P-50 program. Third Video Specification [0064] Headend 110 may receive from an interface to a different environment, such as from a satellite or a storage device, an already compressed 1080P-60 program—a single video stream encoded according to a third video specification and according to a first stream specification. The first stream specification may be a type of transport stream specification suitable for transmission or a type of program stream specification suitable for storage. The third video specification may comprise of the first video specification, the second video specification, or both the first and second video specifications respectively applied, for example, to every other compressed picture. However, the already compressed 1080P-60 program is received at headend 110 encoded in such a way that it does not facilitate reception some of its portions by receivers with processing capability that are less than those of a 1080P-60 receiver. In other words, it is received without information to inherent signal its different portions to receivers with different processing capabilities. [0065] Another novel aspect of this invention is that at least one from one or more encoders, one or more multiplexers, or one or more processing entities at the point of transmission at headend 110 , effect packetization of the compressed pictures of the received 1080P-60 program with a plurality of different PIDS, then transmitting the 1080P-60 program as a plurality of identifiable video streams via the first transmission channel. Thus, headend 110 effects proper packetization and prepending of PID values to enable reception of at least a portion of the 1080P-program to receivers with different processing capabilities that are coupled to network 130 . [0066] The present invention includes methods and systems capable of transmitting compressed video signals according to one or more compression video formats, where compressed video signals correspond to television channels or television programs in any of a plurality of picture formats (i.e., picture spatial resolution and picture rate), including 1080i-60 and 1080P-60 formats. The compressed video signals which correspond to television channels or television programs in any of a plurality of picture formats are received by a plurality of receivers, where each receiver may have a different maximum processing capability. Therefore, the present invention contemplates at least the following combinations for encoding, transmission and reception of video signals. In the following combinations of trio “input/receiver/display,” the input, such as 1080P-60 input in the first combination instance, refers to a compressed video stream that is received at receiver 200 from network 130 via communication interface 242 . The display, such as the 1080P-60 Display in the first combination instance is a television, a display, or a monitor coupled to DHCT 200 via output system 248 . The DHCT 200 provides the compressed video stream corresponding to the “input” in “decoded and reconstructed” form (visible pictures) via output system 248 . The receiver, such as 1080P-60 Receiver in the first combination instance, refers to a receiver, such as DHCT 200 , that has the processing capability specified in the trio. 1080P-60 Input/1080P-60 Receiver/1080P-60 Display [0067] In order to process a 1080P-60 compressed video signal, a 1080P-60 capable receiver receives a compressed 1080P-60 video stream via a network interface (or a communication interface). The 1080P-60 compressed video signal is input by storing it in its memory and the receiver decodes with a video decoder (or decompression engine) all the pictures corresponding to the 1080P-60 video signal (or compressed video stream). A 1080P-60 capable display is driven by all the decoded 1080P-60 pictures. [0000] 1080i-60 Input/1080P-60 Receiver/1080P-60 Display [0068] In order to process a 1080i-60 compressed video signal, the 1080P-60 capable receiver receives a compressed 1080i-60 video stream via a network interface (or a communication interface). The 1080P-60 compressed video signal is input by storing it in its memory and the receiver decodes with a video decoder (or decompression engine) all the pictures corresponding to the compressed 1080i-60 video signal stored in memory. The 1080P-60 receiver then deinterlaces the decoded 1080i-60 signal with a de-interlacing algorithm based on information in two or more 1080i fields, including a current 1080i field. The deinterlacing algorithm makes decisions based on spatial picture information as well as temporal information. The deinterlacing algorithm can further base decisions on motion estimation or motion detection. A 1080P-60 capable display is driven by all the decoded 1080P-60 pictures. 1080P-60 Input/1080P-60 Receiver/Non-1080P-60 Display [0069] In order to process a 1080P-60 compressed video signal, the 1080P-60 capable receiver receives a compressed 1080P-60 video stream via a network interface (or a communication interface). When driving a non-1080P-60 display, the receiver outputs a portion of all the decoded 1080P-60 pictures or processes and scales the pictures of the decoded 1080P-60 signal for display. When driving a non-1080P-60 display such as a 1080i-60 display, the 1080P-60 capable receiver could process a 1080P-60 compressed video signal in full (as explained above) and output (or display) a portion of each of the decoded 1080P-60 pictures. The portion may be a temporally-subsampled portion, a spatially-subsampled portion, or a portion resulting from a combination of a temporal-subsampling and spatially-subsampling. Alternatively, when driving a non-1080P-60 capable display, the 1080P60-capable receiver is informed by the user or through a discovery mechanism that the display is not 1080P-60. Consequently, the 1080P-60-capable receiver can behave as if it was a 1080P-30 receiver by not processing the second video stream. [0000] 1080i-60 Input/1080P-60 Receiver/Non-1080P-60 Display [0070] When driving a non-1080P-60 display, a 1080P-60 receiver processes a 1080i-60 compressed video signal and outputs the decoded 1080i-60 pictures according to the picture format required to drive the non-1080 display, processing and scaling the pictures of the decoded 1080i-60 signal as required to drive the non-1080P-60 display. [0000] 1080P-60 Input/1080i-60 Receiver/Non-1080P-60 Display [0071] In order to process a 1080P-60 compressed video signal, a 1080i-60 capable receiver receives a compressed 1080P-60 video stream via a network interface (or a communication interface). The receiver inputs a first portion of the 1080P-60 compressed video signal by storing it in memory of receiver 200 and the receiver rejects a second and complementary portion of the 1080P compressed video signal by prohibiting it from penetrating any section, portion or buffer of its memory. The receiver 200 decodes with a video decoder (or decompression engine) all the pictures corresponding to the first portion of the 1080P-60 video signal; processing it as if it were a 1080i-60 compressed video signal. A 1080i-60 capable display is driven by the decoded first portion of the 1080P-60 pictures. [0000] 1080P-60 Input/1080i-60 Receiver/1080P-60 Display—A [0072] In order to process a 1080P-60 compressed video signal, a 1080i-60 capable receiver receives a compressed 1080P-60 video stream via a network interface (or a communication interface). The receiver inputs a first portion of the 1080P-60 compressed video signal corresponding to a 1080i-60 compressed video signal by storing it in its memory and rejects a second and complementary portion of the 1080P compressed video signal by prohibiting it from penetrating any section, portion or buffer of its memory. The receiver decodes with a video decoder (or decompression engine) all the pictures corresponding to the first portion of the 1080P-60 video signal, processing it as if it were a 1080i-60 compressed video signal. The receiver deinterlaces a decoded 1080i-60 signal with a deinterlacing algorithm based on information in two or more 1080i fields, including a current 1080i field. The deinterlacing algorithm makes decisions based on spatial picture information as well as temporal information. The deinterlacing algorithm can further base decisions on motion estimation or motion detection. A 1080P-60 capable display is driven by all the decoded and deinterlaced 1080i-60 pictures as a 1080P-60 signal. [0000] 1080P-60 Input/1080i-60 Receiver/1080P-60 Display—B [0073] In order to process a 1080P-60 compressed video signal, a 1080i-60 capable receiver receives a compressed 1080P-60 video stream via a network interface (or a communication interface). The receiver inputs a first portion of the 1080P-60 compressed video signal corresponding to a 1080i-60 compressed video signal by storing it in its memory and rejects a second and complementary portion of the 1080P-60 compressed video signal by prohibiting it from penetrating any section, portion or buffer of its memory. The receiver decodes with a video decoder (or decompression engine) all the pictures corresponding to the first portion of the 1080P-60 video signal, processing it as if it were a 1080i-60 compressed video signal. In order to drive a 1080P-60 capable display that is capable of receiving a 1080i-60 signal and internal deinterlacing, the display is driven by all the pictures of the decoded 1080i-60 compressed video signal as a 1080i-60 signal. The 1080P-60 display deinterlaces the received 1080i-60 signals according to its deinterlacing capabilities. Encoding and Transmission [0074] The encoder produces a 1080P-60 encoded video stream according to a video specification (i.e., MPEG-2 video or MPEG-4 AVC), and assigns a first PID value to packets of every other encoded picture corresponding to the 1080P-60, and assigns a second PID value to every packet of the subsequent picture to the “every other” picture just mentioned, where the second PID value is different from the first PID value. Denoting “every other picture” by N, every subsequent picture is then N+1; and the first PID_value is used for N, while the second PID_value is used for N+1. [0075] The encoder in one embodiment encodes all pictures according to a single video format, e.g., MPEG-4 AVC, and adheres to the buffer model of the video specification. The encoder in a second embodiment encodes the pictures that correspond to N according to a first video specification and in compliance with the video specification's buffering model, and according to a variable-bit rate model. The encoder further encodes the alternate pictures, every “N+1” picture, according to a second video specification, the second video specification being different from the first video specification. These alternate pictures are encoded according to the syntax of the second video specification, but managed and transferred into a transmission buffer according to the first video specification's buffering model. The encoder further employs in its “encoding loop” a model, or parts thereof, of a receiver's video decoder, including reference pictures, in it's memory. [0076] Encode 1080P at 60 frames per second, into a single output, ensuring that every other picture (in both decode order and presentation order) is a non-reference picture. Every picture encoded is a progressive frame representing 1/60 th seconds. Now, every other picture can be separated into a new PID. This new PID may be called “PID B”, and the other PID may be called “PID A”. PID B contains only non-reference pictures that can optionally be included in the decoding of PID A. In this separation process, the original picture ordering must be maintained within the multiplex. For example, a picture in one PID must end before the next picture begins in the other PID. [0077] For backwards-compatibility, the frame rate value in PID A should be set at 30 frames per second; and the temporal references in PID A should be corrected for the separated pictures; and as a convenience, the temporal references in PID B should be set to match those in PID A, such that each picture pair shares a temporal reference number. The 1080P-60 capable decoder will be aware that the frame rate is actually 60 frames per second, and will support the pairs of duplicate temporal references. When decoding both PID A and PID B in combination, the decoder should expect two of every temporal reference number, adjacent in presentation order. Therefore, for example, it can use the temporal reference numbers to detect a missing picture. Picture re-ordering within the decoder may be based on the sequence of picture types received, as normal. [0078] The following are examples of this scheme demonstrating how a decoder could receive PID A alone, or receive the combination of PID A and PID B. In these examples, the “B”-type pictures represent non-reference frames. Also, these examples are given in decode order, and the numbers represent temporal references (indicating presentation order). [0000] Example 1, IBBBP . . . : Before temporal reference number (TRN) correction: PID A: I3_B1_P7_B5_P11_B9_P15_B13 — PID B: _B0_B2_B4_B6_B8_B10_B12_B14 After TRN correction: PID A: I1_B0_P3_B2_P5_B4_P7_B6 — PID B: _B0_B1_B2_B3_B4_B5_B6_B7 Example 2, IBP . . . : Before TRN correction: PID A: I1_P3_P5_P7_P9_P11_P13_P15 — PID B: _B0_B2_B4_B6_B8_B10_B12_B14 After TRN correction: PID A: I0_P1_P2_P3_P4_P5_P6_P7 — PID B: _B0_B1_B2_B3_B4_B5_B6_B7 In the PMT, PID B can be designated by a new stream_type. A common set of audio streams may serve each case: 1) using only PID A 2) using both PID A and PID B. [0079] In the above described method of encoding and transmission, the separation of every other frame occurred after encoding. In an alternative embodiment, separation occurs prior to encoding. At one encoder's input, supply every other frame of a 1080P-60 hz signal. Encode this as 1080P-30 hz. Simultaneously, supply another encoding process with the alternate frames, also at 1080P-30 hz. Presentation time stamps (PTSs) shall be generated for every picture, referencing a common clock. The result is two video streams, each being legitimate 1080P-30 hz. A 1080P-60 capable decoder may decode both simultaneously, as a dual-decode operation, to be recombined in the display process. There need be no further correlation between the two PIDs than the commonly referenced PTSs. For example, the group of pictures (GOP) structures, as defined by the video specification (e.g., MPEG-2 video GOP) may be independent, and the buffering may be independent. To recombine the dual 1080P-30 streams into a single 1080P-60 output, the dual-decoder's display process will choose decoded pictures to put on display in order of PTS. If the picture for a particular time interval has not yet been decoded, possibly due to some data corruption or loss, then the previous picture will simply be repeated through that time interval. If any picture is decoded later than its PTS elapses, it is to be discarded. Even though both PIDs may be completely independent, because they reference the same clock, there is no risk that a picture from one PID is sent later than the presentation time of a following picture from the other PID, as long as each PID's buffer is maintained compliantly within the multiplex. [0080] PID B in the PMT may be designated by a new stream_type, which may be allocated by MPEG, or which may be a user-private stream_type that indicates a privately managed stream. The new stream_type would not be recognized by legacy receivers, so the associated PID B would be ignored. As an additional method of unambiguous identification of the special second PID, the registration_descriptor may be used in the ES_descriptor_loop of the PMT to register a unique and private attribute for association with PID B. Any combination of the above methods may be used, as deemed adequate and sensible. A common set of audio streams may serve each case: 1) using only PID A 2) using both PID A and PID B. The methods described above use a separate PID to carry additional information. In those cases, the separate PID can optionally be ignored by the decoder. In another alternative embodiment, a single video PID may be used to carry both the base information and the additional information, while still providing a way to optionally reject the additional information. A separate packetized elementary stream (PES) ID can be used such that a new PMT descriptor, which would be allocated by MPEG, may designate one PES ID for the base layer, and a different PES ID for the additional information, both carried by the same PID. In this way, existing PES IDs may be identified as base, and supplemental, without the need for new PES IDs to be allocated. The decoder that needs only the base layer may discard those PES packets whose ID does not match the ID designated as the base layer in the PMT. The decoder that can use both may simply not reject either. This approach is applicable to both schemes: post-encoding-separation and prior-encoding-separation. [0081] The foregoing has broadly outlined some of the more pertinent aspects and features of the present invention. These should be construed to be merely illustrative of some of the more prominent features and applications of the invention. Other beneficial results can be obtained by applying the disclosed information in a different manner or by modifying the disclosed embodiments. Accordingly, other aspects and a more comprehensive understanding of the invention may be obtained by referring to the detailed description of the exemplary embodiments taken in conjunction with the accompanying drawings, in addition to the scope of the invention defined by the claims.

Methods and systems for the efficient and non-redundant transmission of a single video program in multiple frame rates, optionally employing a combination of video coding standards, in a way that is backwards-compatible with legacy receivers only supportive of some subsection of frame rates or of some subsection of video coding standards.

CROSS-REFERENCE TO RELATED APPLICATIONS The present patent application is a US National Stage of International Application No. PCT/CA2013/000884, filed on Oct. 15, 2013, which claims priority under 35 USC §119(e) of U.S. provisional Application Ser. No. 61/713,226, filed on Oct. 12, 2012, the contents of which are hereby incorporated by reference. FIELD OF THE INVENTION The present invention relates to methods for evaluating scoliosis prognosis. In particular, the present invention relates to methods and systems for predicting the progression of scoliosis, stratifying a subject having a scoliosis and assessing the efficacy of a brace on a subject having a scoliosis. BACKGROUND Spinal deformities and scoliosis in particular, represent the most prevalent type of orthopedic deformities in children and adolescents. Adolescent idiopathic scoliosis (AIS) is a three-dimensional spinal deformity with a prevalence of 1.34% in children between 6 and 17 years old for a Cobb angle of 10° or more. Classical risk factors such as skeletal maturity, initial Cobb angle and type of curvature were found to predict final Cobb angle but to a certain extent only. There is still no reliable method to predict whether an individual's curve will progress and how severe the progression will be. Current treatments are only available to patients with a curvature>25°. The only treatment available today for patients with a moderate curvature (<40° but >25°) is external bracing. Bracing never corrects a curve but rather stabilizes the curve during the time an adolescent is growing, although its effectiveness is questionable (50% of those wearing a brace simply do not benefit). It has also been shown that bracing typically proves ineffective on two (2) patients out of three (3). For patients with a curvature >40°, the current option is the surgical correction. Unfortunately, there is no proven method available to identify which affected children or adolescents may require treatment based on the risk of progression. Consequently, the application of current treatments is delayed until a significant deformity is detected or until a significant progression is clearly demonstrated, resulting in a delayed and less optimal treatment. Also, the uncertainty related to curve progression and outcome creates anxiety for families and patients with scoliosis as well as unnecessary psychosocial stresses associated with brace treatment. The failure to accurately predict the risk of progression can also lead to inadequate treatment, as well as unnecessary medical visits and radiographs. There is thus a need for a method of predicting the scoliosis curve progression, particularly in treatment decisions for individuals who are diagnosed with scoliosis. SUMMARY There is described herein a method and system for predicting scoliosis curve progression based on measuring a combination of predictive factors. A predictive model is created based on type of curvature, skeletal maturity and three-dimensional (3D) spine parameters. The predictive model may thus enable early prognosis of scoliosis, stratifying of subjects having a scoliosis as well as early clinical intervention to mitigate progression of the disease. It may also allow selection of subjects for clinical trials involving less invasive treatment methods. The 3D spine parameters are selected from one or more of the six categories of 3D measurements or parameters: angle of plane of maximum curvature, initial Cobb angles (kyphosis, lordosis), 3D wedging (apical vertebra, apical disks), rotation (upper and lower junctional vertebra, apical vertebra, thoracolumbar junction and mean peri-apical intervertebral) rotation, torsion (geometrical and/or mechanical torsion) and slenderness (height/width ratio). In accordance with a broad aspect, there is provided a system for generating a final Cobb angle prediction for idiopathic scoliosis, the system comprising a memory having stored thereon a predictive model based on 3D morphological spine parameters, curve type, and skeletal maturity; a processor; and at least one application stored in the memory and executable by the processor for receiving patient-specific 3D morphological spine parameters, a selected curve type, and a selected skeletal maturity, retrieving the predictive model, and modeling a progression curve of the idiopathic scoliosis to generate the final Cobb angle prediction. In some embodiments, the at least one application is further configured to receive two-dimensional spine data, reconstruct a three-dimensional spine morphology, and extract the patient-specific 3D morphological spine parameters therefrom. In some embodiments, the patient-specific 3D morphological spine parameters comprise at least one of an initial Cobb angle, a plane of maximal deformation, a three-dimensional wedging of vertebral body and disk, an axial intervertebral rotation of an apex, upper and lower junctional level and thoracolumbar level, slenderness, and torsion. In some embodiments, the at least one application is executable by the processor for computing the initial Cobb angle in at least one of a frontal plane of the reconstructed three-dimensional spine morphology, a sagittal plane of the reconstructed three-dimensional spine morphology, and the plane of maximal deformation. In some embodiments, the at least one application is executable by the processor for applying the patient-specific 3D morphological spine parameters, the selected curve type, and the selected skeletal maturity to the retrieved predictive model for modeling the progression curve from the initial Cobb angle to a predicted final Cobb angle, the predicted final Cobb angle indicative of a forecasted evolution of the idiopathic scoliosis at the selected skeletal maturity. In some embodiments, the at least one application is executable by the processor for computing the plane of maximal deformation as a plane in the reconstructed three-dimensional spine morphology having an axial angle that extends around a direction in which the initial Cobb angle is maximal. In some embodiments, the at least one application is executable by the processor for computing three-dimensional wedging of junctional and peri-apical disk levels of the reconstructed three-dimensional spine morphology, and a sum of three-dimensional wedging of all thoracic and lumbar disks of the reconstructed three-dimensional spine morphology. In some embodiments, the at least one application is executable by the processor for computing the axial intervertebral rotation of a superior vertebra of the reconstructed three-dimensional spine morphology relative to an inferior vertebra of the reconstructed three-dimensional spine morphology, the inferior vertebra adjacent the superior vertebra and the superior and inferior vertebrae each having defined therefor in the reconstructed three-dimensional spine morphology a local axis plane comprising a first axis, the rotation computed by projecting the first axis of the superior vertebra onto the local axis plane of the inferior vertebra. In some embodiments, the at least one application is executable by the processor for computing the slenderness as a ratio of a height to a width of a body of each one of thoracic and lumbar vertebrae of the reconstructed three-dimensional spine morphology. In some embodiments, the at least one application is executable by the processor for receiving the patient-specific 3D morphological spine parameters comprising at least one of a mechanical torsion and a geometrical torsion. In some embodiments, the at least one application is executable by the processor for calculating the mechanical torsion by computing a first sum of the axial intervertebral rotation for all vertebrae in a first hemicurvature of a main idiopathic scoliosis curve in the reconstructed three-dimensional spine morphology, a second sum of the axial intervertebral rotation for all vertebrae in a second hemicurvature of the main curve, and a mean of the first sum and the second sum, the first hemicurvature defined between an upper end vertebra and an apex of the main curve and the second hemicurvature defined between a lower end vertebra of the main curve and the apex. In some embodiments, the at least one application is executable by the processor for receiving the selected curve type comprising one of single right thoracic, double with main thoracic, double with main lumbar, triple, single left thoracolumbar, single left lumbar, and left thoracic-right lumbar. In some embodiments, the at least one application is executable by the processor for receiving the selected skeletal maturity comprising skeletal maturity data indicative of one of a first stage skeletal maturity and a second stage skeletal maturity, the first stage skeletal maturity characterized by an open triradiate cartilage with a Risser grade equal to zero and the second stage skeletal maturity characterized by one of a Risser grade equal to one and a closed triradiate cartilage with a Risser grade equal to zero. In some embodiments, the memory has stored therein a plurality of treatment options each suitable for treating the idiopathic scoliosis and having associated therewith at least one of a range of final Cobb angles and a rate of change of idiopathic scoliosis curve progression, and further wherein the at least one application is executable by the processor for querying the memory with at least one of the final Cobb angle prediction and the modelled progression curve to retrieve a selected one of the plurality of treatment options and for outputting the final Cobb angle prediction and the selected treatment option. In some embodiments, the memory has stored thereon the predictive model comprising a general linear statistical model associating the final Cobb angle prediction with selected predictors, the selected predictors comprising the 3D morphological spine parameters, curve type, and skeletal maturity and determined by a backward selection procedure. In accordance with another broad aspect, there is provided a computer-implemented method for generating a final Cobb angle prediction for idiopathic scoliosis, the method comprising receiving patient-specific 3D morphological spine parameters, a selected curve type, and a selected skeletal maturity; applying the patient-specific 3D morphological spine parameters, a selected curve type, and a selected skeletal maturity to a predictive model based on 3D morphological spine parameters, curve type, and skeletal maturity, and generating the final Cobb angle prediction by modeling a progression curve of the idiopathic scoliosis. In some embodiments, the method further comprises receiving two-dimensional spine data, reconstructing a three-dimensional spine morphology, and extracting the patient-specific 3D morphological spine parameters therefrom. In some embodiments, receiving the patient-specific 3D morphological spine parameters comprises receiving at least one of an initial Cobb angle, a plane of maximal deformation, a three-dimensional wedging of vertebral body and disk, an axial intervertebral rotation of an apex, upper and lower junctional level and thoracolumbar level, slenderness, and torsion. In some embodiments, receiving the patient-specific 3D morphological spine parameters comprises receiving the initial Cobb angle computed in at least one of a frontal plane of the reconstructed three-dimensional spine morphology, a sagittal plane of the reconstructed three-dimensional spine morphology, and the plane of maximal deformation. In some embodiments, receiving the patient-specific 3D morphological spine parameters comprises receiving the plane of maximal deformation as a plane in the reconstructed three-dimensional spine morphology having an axial angle that extends around a direction in which the initial Cobb angle is maximal. In some embodiments, receiving the patient-specific 3D spine parameters comprises receiving three-dimensional wedging of junctional and peri-apical disk levels of the reconstructed three-dimensional spine morphology and a sum of three-dimensional wedging of all thoracic and lumbar disks of the reconstructed three-dimensional spine morphology. In some embodiments, receiving the patient-specific 3D morphological spine parameters comprises receiving the axial intervertebral rotation computed for a superior vertebra of the reconstructed three-dimensional spine morphology relative to an inferior vertebra of the reconstructed three-dimensional spine morphology, the inferior vertebra adjacent the superior vertebra and the superior and inferior vertebrae each having defined therefor in the reconstructed three-dimensional spine morphology a local axis plane comprising a first axis, the rotation computed by projecting the first axis of the superior vertebra onto the local axis plane of the inferior vertebra. In some embodiments, receiving the patient-specific 3D morphological spine parameters comprises receiving the slenderness computed as a ratio of a height to a width of a body of each one of thoracic and lumbar vertebrae of the reconstructed three-dimensional spine morphology. In some embodiments, receiving the patient-specific 3D morphological spine parameters comprises receiving the torsion obtained by computing a first sum of the axial intervertebral rotation for all vertebrae in a first hemicurvature of a main idiopathic scoliosis curve in the reconstructed three-dimensional spine morphology, a second sum of the axial intervertebral rotation for all vertebrae in a second hemicurvature of the main curve, and a mean of the first sum and the second sum, the first hemicurvature defined between an upper end vertebra and an apex of the main curve and the second hemicurvature defined between a lower end vertebra of the main curve and the apex. In some embodiments, the method further comprises querying a memory with at least one of the generated final Cobb angle prediction and the modelled progression curve to retrieve a selected one of a plurality of treatment options stored in the memory, each of the plurality of treatment options suitable for treating the idiopathic scoliosis and having associated therewith at least one of a range of final Cobb angles and a rate of change of idiopathic scoliosis curve progression, and outputting the final Cobb angle prediction and the selected treatment option. In accordance with yet another broad aspect, there is provided a computer readable medium having stored thereon program code executable by a processor generating a final Cobb angle prediction for idiopathic scoliosis, the program code executable for receiving patient-specific 3D morphological spine parameters, a selected curve type, and a selected skeletal maturity; applying the patient-specific 3D morphological spine parameters, a selected curve type, and a selected skeletal maturity to a predictive model based on 3D morphological spine parameters, curve type, and skeletal maturity, and generating the final Cobb angle prediction by modeling a progression curve of the idiopathic scoliosis. This technique of predicting scoliosis curve progression may help monitor patients with AIS and help tailor their treatment plan accordingly. For the present specification, “Cobb angle” refers to a measure of the curvature of the spine, determined from measurements made on X-ray photographs. Specifically, scoliosis is defined by the Cobb angle. The Cobb angle is illustratively computed as the angle formed between a line drawn parallel (or perpendicular) to the superior endplate of the uppermost vertebra involved in the AIS deformity a line drawn parallel (or perpendicular) to the inferior endplate of the lowermost vertebra involved. A lateral and rotational spinal curvature of the spine with a Cobb angle of >10° is defined as scoliosis. “Risser sign” refers to a measurement of skeletal maturity. Skeletal maturity can be divided into three sequential stages: 1) Risser 0 with open triradiate cartilage, 2) Risser 0 with closed triradiate cartilage or Risser 1, and 3) Risser 2 or greater. The second stage correlates with the rapid acceleration phase. More precisely, a Risser sign is defined by the amount of calcification present in the iliac apophysis, divided into quartiles, and measures the progressive ossification from anterolaterally to posteromedially. A Risser grade of 1 signifies up to 25 percent ossification of the iliac apophysis, proceeding to grade 4, which signifies 100 percent ossification. A Risser grade of 5 means the iliac apophysis has fused to the iliac crest after 100 percent ossification. Children usually progress from a Risser grade 1 to a grade 5 over a two-year period during the most rapid skeletal growth. Many other uses and advantages of the present invention will be apparent to those skilled in the art upon review of the detailed description herein. Solely for clarity of discussion, the invention is described in the sections below by way of non-limiting examples. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates a 3D reconstruction of a scoliotic spine with plane of maximal deformity represented by a triangle for each curvature (thoracic proximal curve, main thoracic and lumbar) in the axis system with <<x>> axis anterior, <<y>> axis left and <<z>> axis cephalad; FIG. 2A illustrates the Vertebral body 3D wedging; FIG. 2B is an illustration of the mean of the two apical 3D disks wedging; FIG. 3A is an illustration of intervertebral rotation; FIG. 3B in an illustration of slenderness with height/width (h/w) ratio of a single vertebral body; FIG. 4 is an illustration of torsion. χ (mean) Σ (sum) θ (angle); FIG. 5 is a flowchart of an exemplary method for creating a predictive model for AIS; FIG. 6 represents the frequency histogram with final Cobb angle on <<x>> axis and frequency on <<y>> axis with a normal curve illustrated; FIG. 7 is a block diagram of an exemplary system for predictive modeling of AIS; FIG. 8 is a block diagram of an exemplary system for the predictive model system of FIG. 7 ; and FIG. 9 is a block diagram of an exemplary application running on the predictive model system of FIG. 8 . DETAILED DESCRIPTION There is described a method and system for predicting final Cobb angle in idiopathic scoliosis based on information available at a first visit. In one embodiment, the method and system apply to AIS, as described herein. It should however be understood that other types of scoliosis, such as early onset idiopathic scoliosis, may also apply. A plane of maximal curvature is provided as a risk factor of progression. One or more of the following predictive factors are combined in order to obtain the predictive model: type of curvature, skeletal maturity, initial Cobb angle, angle of plane of maximal curvature, 3D wedging of junctional and peri-apical disks (e.g. T3-T4, T8-T9, T11-T12 disks) and sum of thoracic and lumbar 3D disks wedging. Classical risk factors such as skeletal maturity, initial Cobb angle and type of curvature are found to predict final Cobb angle to a certain extent. The addition of the plane of maximal curvature as well as the sum of the disk wedging of the thoracic and lumbar levels and three specific 3D junctional and peri-apical disks wedging levels (e.g. T3-T4, T8-T9, T11-T12) improves the overall prediction of the final Cobb angle. A study was performed with the objective of developing a predictive model of the final Cobb angle in adolescent idiopathic scoliosis based on 3D spine parameters. A prospective cohort was recruited in a single center from January 2006 to May 2010. The inclusion criteria were (1) first visit with an orthopedic surgeon with a diagnosis of AIS, (2) Cobb angle between 11 and 40 degrees, and (3) Risser sign of 0 or 1. The exclusion criteria were (1) congenital, neuromuscular or syndromic scoliosis. Patients with a Risser sign of 2 or greater were also excluded. Curves greater than 40 degrees were also excluded because they fall into a category in which some surgeons will consider a fusion surgery. At the first and for all subsequent visits, each patient had a lateral and PA spine radiographs. Patients were followed by one of four (4) spine surgeons with intervals of follow up chosen by treating surgeon. The endpoint for the study occurred when patients reached skeletal maturity (at least Risser 4) or when a fusion surgery was performed. Brace treatment was allowed according to the treating physician, but brace had to be removed the night before appointment. For all patients, the curve type was defined either as a single right thoracic, double with main thoracic, double with main lumbar, triple, single left thoracolumbar, single left lumbar or other (left thoracic and right lumbar). The Risser sign and triradiate cartilage status (open or closed) was evaluated at the first visit. The skeletal maturity status was set as either stage 0 (open triradiate cartilage and Risser 0) or stage 1 (Risser 0 with closed triradiate cartilage or Risser 1). All patients had a 3D spinal reconstruction of the spine at the first visit from the PA and lateral radiographs. Reconstructions were done with two softwares: Spine 3D (LIS3D, Montreal, Canada) and IdefX (LIO, Montreal, Canada), by one research assistant expert in the technique. Two different softwares were used in order to conform with the specifications proper to each of the two radiographic imaging systems used in the current study: Spine 3D was used with the Fuji system (58 first patients of the cohort) and IdefX was used with the EOS™ system (75 last patients of the cohort). The Spine 3D software uses algorithms based on direct linear transformation combined with the Non Stereo Corresponding Points algorithm (NSCP); this is based on identification of corresponding anatomical landmarks on vertebrae from stereo-radiographs. IdefX software uses a semi-automated (SA) method based on a priori knowledge. Both softwares generated 3D reconstructions of comparable accuracy. There is no difference in terms of mean errors between 3D vertebral models obtained from stereo-radiography (NSCP and SA) and CT-scan reconstructions. The precision of these reconstructions has been shown to be very satisfactory with mean point-to-surface errors of less than 1.5 mm and less than two degrees for angular measurements when compared to conventional CT-Scan reconstructions. All measurements were computerized 3D radiologic measurements done with the same custom software IdefX (LIO, Montreal, Canada) for all reconstructions. The calculated 3D parameters were illustratively divided in six (6) categories consisting of global (whole spine), regional (scoliotic segment) or local (vertebra) descriptors. The centroid of each vertebra is defined as the point half way between the center of the upper and lower endplates of the vertebra. The global axis system is defined by the SRS 3D terminology group as follows: the origin is at the center of the upper endplate of S1, the <<z>> axis is vertical (gravity line) and the <<y>> axis is between the anterior superior iliac spine and pointing to the left. The local vertebra axis system is defined by the SRS 3D terminology group as follows: the origin is at the centroid of the vertebral body, the local ‘z’ axis passes through the centers of the upper and lower endplates and pointing in a cephalad direction, and ‘y’ axis is parallel to a line joining similar landmarks on the bases of the right and left pedicles pointing to the left. An exemplary set of the 3D parameters for each parameter category is as follows. It should be understood that each parameter category may comprise several 3D parameters. 1—Cobb Angles: Cobb angles were defined as the angle between the upper and lower end plate of the respective end vertebrae of a curve. Cobb angle was measured in the frontal plane, in the plane of maximal deformation in 3D and in the sagittal plane for thoracic kyphosis (T4-T12) and lumbar lordosis (L1-L5). 2—Plane of maximal deformation: Referring now to FIG. 1 , there is illustrated a plane 102 of maximal deformation. The axial angle (not shown) of the plane 102 is around a direction, e.g. a global z-axis, in which the Cobb angle is maximal. The plane 102 of maximal deformation is illustratively represented by a triangle 104 1 , 104 2 , 104 3 for each curvature in the spine 106 , e.g. for the thoracic proximal curve, main thoracic curvature, and lumbar curvature, respectively. 3—Three-dimensional wedging of vertebral body and disk: FIGS. 2 a and 2 b illustrate three-dimensional wedging θ 3D of vertebral body and disk. Wedging of the apical vertebral body 202 in the plane 102 of maximal deformation (3D plane) and mean maximal 3D wedging of the two apical intervertebral disks as in 204 1 , 204 2 are shown. Maximal 3D wedging represents the wedging measured in the plane, wherein the wedging value is maximal around the vertical axis. If the apex was a disk (see FIG. 2 b ), then the mean of the 3D wedging θ 1 3D , θ 2 3D of both apical vertebral bodies was calculated and only the 3D wedging of the apical disk was reported instead of the mean of two apical disks. 3D disk wedging was analyzed for all levels of the thoracic and lumbar spine (from T1-T2 to L4-L5). 4—Axial intervertebral rotation of the apex, upper and lower junctional level and thoracolumbar level: This is shown in FIG. 3 a . In particular, rotation between two adjacent vertebrae 302 1 , 302 2 at upper, apical and lower curve level and thoracolumbar junction (T12-L1) with reference to the local axis system of the inferior vertebra 302 2 are illustrated. The rotation θ AXIAL of the superior vertebra 302 1 with respect to the inferior vertebra 302 2 was calculated after projecting the local x-axis of the superior vertebra 302 1 into the x-y plane of the local axis system of the inferior vertebra 302 2 . The definition of the SRS 3D terminology group for the intervertebral rotation is the projected angles between the local axis of two adjacent vertebrae. 5—Slenderness: FIG. 3 b illustrates slenderness (local T6, T12 and L4 and regional T1-L5), or the ratio between the height h (distance between the superior and inferior end plates at the center of the vertebrae) and the width w (measured at the center of the vertebrae using a line perpendicular to the height line in medio-lateral direction) of the vertebral body for T6, T12 and L4 vertebrae. Ratio may also be found between the length of the spine between T1 and L5 and the mean of the width of vertebral bodies of T6, T12 and L4. The same calculations were made with the width being replaced by the depth (a line perpendicular to the height line at the center of the vertebra in the anteroposterior direction). The length between T1-L5 is the length of a line starting at the center of the upper endplate of T1, passing through the centroid of all vertebrae down to the center of the lower endplate of L5. The line was smoothed using a cubic spline function. T6 and L4 were selected and T12 was added as a thoracolumbar landmark. It should however be understood that slenderness calculation is not limited to T6, T12, and L4 vertebrae and may apply to any thoracic or lumbar vertebra. 6—Torsion: FIG. 4 illustrates mechanical torsion, or the mean of the sum of intervertebral axial rotation (measured according to the local referential of the inferior vertebrae) for all vertebrae included in the two hemicurvatures (between upper end vertebra and apex and between lower end vertebra and apex, not shown) of the main scoliotic curve 402 of the spine 106 . For this purpose, a first sum Σθ AXIAL1 of intervertebral axial rotation for all vertebrae in the first hemicurvature (not shown) is computed. A second sum Σθ AXIAL2 of intervertebral axial rotation for all vertebrae in the second hemicurvature (not shown) is further computed. The mean of the first and second sums Σθ AXIAL1 , Σθ AXIAL2 is then computed to obtain the value of the torsion. As discussed above, geometrical torsion may also apply. In a specific embodiment, the output of the prediction method was defined as the main Cobb angle measured on a posteroanterior (PA) radiograph at the earliest visit where skeletal maturity (minimum Risser 4) was reached or just before fusion surgery. FIG. 5 is a flowchart of an exemplary method for generating the predictive model 500 . The first step 502 was to assess the normality of the output data from a frequency histogram as well as from subjective analysis of the normal distribution. Due to the large number of variables, the second step 504 was to do univariate analyses to select the most relevant predictors to be included in the multivariate analysis. Initially, the correlations between final Cobb angle at skeletal maturity and local, regional and global parameters of the spine can be performed in order to identify parameters associated with a p value of 0.1 or less. The third step 506 was done to reduce the number of categories for the curve type. A one-way analysis of variance (ANOVA) can be done to compare the six different curve types in terms of final Cobb angle at skeletal maturity with a level of significance of 0.05, in order to merge curve types resulting in similar final Cobb angle at skeletal maturity. The objective of this step was to reduce the number of different categories for the type of curve input in the model. The final step 508 consisted in creating the predictive model based on a General Linear Model (GLM). A backward selection procedure approach was performed to select predictors. P-values were first obtained for each predictor included in the full model (curve type and skeletal maturity stage were included as fixed factors and all retained spinal parameters were included as covariates). Interaction was added between categorical variable to test if a change in the simple main effect of one variable over the level of the second was significant. The predictor with the larger p-value was then eliminated and the model was refitted. This was done until all remaining predictors were associated with a p-value smaller than the stopping criterion set at 0.05. In the GLM, association between the final Cobb angle at skeletal maturity and selected predictors was assessed and expressed as beta coefficient (β coefficient) and 95% confidence interval (CI). All statistical analyses were done with SPSS 20.0 software package (SPSS, inc., Chicago, Ill., USA). In one exemplary embodiment, a prospective cohort of 133 AIS was followed from skeletal immaturity to maturity (mean 37 months). A total of 172 AIS patients were entered in the cohort. At the time of the analysis, 133 patients could be included (77.3%). Overall, 17 were lost to follow up, 13 were still skeletally immature and 3D reconstruction was impossible for 9 patients due to calibration errors. Descriptive characteristics of the cohort are presented in table 1, using the following acronyms: n (sample size), TR (triradiate cartilage), RT (right thoracic), RT-LL (right thoracic-left lumbar), LL-RT (left lumbar-right thoracic), LTL (left thoracolumbar), other (left thoracic, right lumbar). TABLE 1 Cohort N 133 Age (years) 12.6 ± 1.2 Sex Male 16 Female 117 Risser 0 and TR open 48 0 and TR closed 47 1 38 Cobb angle (degrees) 22.1 ± 8.4 Follow up (month)  36.7 ± 13.6 Type RT 35 RT-LL 22 LL-RT 26 Triple 7 LTL 36 Other 7 Treatment Observation 51 Brace 66 Fusion surgery 16 Computerized measurements were done on reconstructed 3D spines radiographs of the first visit. There were six (6) categories of measurements or parameters, each category comprising several measurements or parameters: angle of plane of maximum curvature, Cobb angles (kyphosis, lordosis), 3D wedging (apical vertebra, apical disks), rotation (upper and lower junctional vertebra, apical vertebra, thoracolumbar junction), mean peri-apical intervertebral rotation (geometrical and/or mechanical torsion) and slenderness (height/width ratio). A general linear model analysis with backward procedure was done with final Cobb angle (either just before surgery or at skeletal maturity) as outcome and 3D spine parameters as predictors. Skeletal maturity stage and type of curvature were also included in the model. In a specific embodiment, the predictive model was obtained with a determination coefficient of 0.715. Included predictors were a three (3) stages skeletal maturity system and type of curvature. The initial frontal Cobb angle was also included as well as the angle of the plane of maximal curvature. The four (4) other predictive factors of final Cobb angle were the 3D wedging of T3-T4, T8-T9 and T11-T12 disks, and the sum of 3D wedging of all thoracic and lumbar disks. As discussed above, it should be understood that, in other embodiments, 3D wedging of junctional and peri-apical disk levels other than T3-T4, T8-T9, and T11-T12 may apply. The final Cobb angle distribution followed a normal distribution, as shown by the histogram presented in FIG. 6 . Pearson's correlations with the final Cobb angle were done for a total of forty-one (41) spinal parameters. There were thirty (30) parameters resulting in a correlation associated with a p-value under 0.1. The results of the correlation analysis are illustrated in table 2. TABLE 2 Parameters Pearson coefficient P-value 3D kyphosis (T4-T12) −0.285 0.001 Mean apical disks 3D wedging 0.364 0.000 Proximal disk 3D wedging 0.23 0.007 Distal disk 3D wedging −0.174 0.043 Distal IV rotation −0.16 0.063 Thoracolumbar IV rotation (T12-L1) −0.159 0.071 Apical IV rotation −0.164 0.057 Cobb angle in the plane of maximal 0.287 0.001 deformation Angle of the plane of maximal 0.501 0.000 deformation Torsion 0.412 0.000 Cobb angle frontal plane 0.659 0.000 T6 Slenderness (depth) −0.169 0.050 T6 Slenderness (width) −0.183 0.034 L4 Slenderness (depth) −0.203 0.018 L4 Slenderness (width) −0.165 0.055 T1-L5 Slenderness (width) −0.226 0.008 T1-L5 Slenderness (depth) −0.198 0.021 T1-T2 3D disk wedging 0.379 0.000 T2-T3 3D disk wedging 0.268 0.002 T3-T4 3D disk wedging 0.386 0.000 T5-T6 3D disk wedging 0.182 0.034 T6-T7 3D disk wedging 0.192 0.025 T7-T8 3D disk wedging 0.33 0.000 T8-T9 3D disk wedging 0.466 0.000 T9-T10 3D disk wedging 0.314 0.000 T10-T11 3D disk wedging 0.341 0.000 T11-T12 3D disk wedging 0.249 0.004 T12-L1 3D disk wedging 0.305 0.000 L1-L2 3D disk wedging 0.184 0.033 Sum of 3D disks wedging 0.412 0.000 (Thoracic and lumbar) For the type of curvature, the ANOVA analysis reduced the six (6) categories into four (4) types which are (1) right thoracic, double with main left lumbar and other type (left thoracic, right lumbar), (2) triple, (3) left thoracolumbar, and (4) double with main right thoracic. With regards to the GLM analysis, skeletal maturity, type of curve, 2D initial Cobb angle, angle of the plane of maximal deformation, disk wedging of T3-T4, T8-T9, T11-T12 and sum of lumbar and thoracic wedging were found to be predictors of the final Cobb angle. Table 3 illustrates the GLM (R 2 =0.715, F=22.956, p<0.000) to determine predictors of final Cobb angle. TABLE 3 Esti- mated coef- 95% CI p- Parameters n ficient Upper Lower value Intercept 133 0.288 −7.788 8.364 0.944 Angle of plane of 133 0.177 0.097 0.256 0.000 maximal curvature 2D Cobb angle 133 0.714 0.479 0.949 0.000 T3-T4 disk wedging 133 1.185 0.456 1.914 0.002 T8-T9 disk wedging 133 0.992 0.24 1.745 0.010 T11-T12 disk wedging 133 0.868 0.133 1.603 0.021 Sum of all thoracic and 133 −0.134  −0.251 −0.016 0.026 lumbar disk wedging Matu- 0 48 8.7  1.041 16.359 0.026 rity 1 85 0 b    Type of 1 68 −4.566  −9.599 0.466 0.075 curvature 2 7 3.959 −8.637 16.556 0.535 3 36 −3.201  −8.728 2.326 0.254 4 22 0 b    Matu- Interaction Type rity 1 0 26 −2.868  −11.454 5.718 0.510 1 1 42 0 b    2 0 5 8.969 −6.854 24.793 0.264 2 1 2 0 b    3 0 10 −14.56   −24.276 −4.843 0.004 3 1 26 0 b    4 0 7 0 b    4 1 15 0 b    All continuous predictors increased the final value of Cobb angle except the sum of disk wedging for which the β coefficient is negative (−0.134). The initial Cobb angle has a coefficient of 0.714. If the patient has a skeletal maturity stage of 0, 8.7° are added to the final Cobb angle prediction when compared to a similar patient with skeletal maturity stage 1. For the type of curvature, 4.6° (type 1) or 3.2° (type 3) are subtracted to the final Cobb angle, or 4.0° is added for type 2, when compared to a similar patient with a type 4 curve. This is adjusted with the interaction contribution. A type 1 with 0 as maturity stage will have 2.9° subtracted, a type 2 with 0 as maturity stage will have 9.0° added and type 3 with 0 as maturity stage will have 14.6° subtracted to the final Cobb angle prediction. R2 of this predictive model is 0.715, which means that it explains 71.5% of variance. Some p-values for the categorical predictors are over 0.05 when evaluating their main effect in the GLM. However, these categorical predictors were kept in the model because their contribution was significant when considered in interaction between each other. Predictors of progression were identified for immature patients with AIS that will facilitate the prediction of progression until skeletal maturity in mild and moderate curves with a Cobb angle between 11° and 40°. The prediction model can explain 71.5% of the variance in the final Cobb angle at skeletal maturity using only information taken from the initial visit. Basics predictors included in the model are the Cobb angle, type of curvature and skeletal maturity at the initial visit. One 3D parameter comprised in the model is the angle of the plane of maximal deformation. This parameter is associated with the rotation of the curve and may be more sensitive to detect progressive AIS than traditional Cobb angle. The four (4) other predictors comprised in the model are disc wedging (at junctional and peri-apical disk levels, e.g. T3-T4, T8-T9, T11-T12, and sum of all). T3-T4 and T11-T12 levels that were identified usually represent junctional level and T8-T9 either junctional or apical level depending on the type of curvature (for a thoracic curve it will represent apical level and for thoracolumbar curve, junctional level). Wedging of T3-T4 disks has the largest effect on final Cobb angle prediction. The statistical model chosen was a GLM with a backward procedure to select the predictors. A stepwise selection variant is widely used in medical application and it was chosen because it represents a good strategy to find the best fitting model. It is accepted that a sample size of more than a hundred (100) is required for linear modeling. Another way to determine the sample size of linear modeling is to have at least ten (10) times the degree of freedom included in model. This model has thirteen (13) degrees of freedom (six (6) continuous predictors, one (1) for maturity stage, three (3) for curve type and three (3) for the combination of maturity stage and type of curvature), so the sample size of one hundred and thirty three (133) is suitable. Referring to FIG. 7 , a communication system 700 for providing health care providers with support in predicting a curve of progression for AIS will now be described. The system 700 comprises a plurality of devices as in 702 adapted to communicate with a predictive model system 704 over a network 706 . The devices 702 comprise any device, such as a personal computer, a personal digital assistant, a smart phone, or the like, which is configured to communicate over the network 706 , such as the Internet, the Public Switch Telephone Network (PSTN), a cellular network, or others known to those skilled in the art. Although illustrated as being separate and remote from the devices 702 , it should be understood that the predictive model system 704 may also be integrated with the devices 702 , either as a downloaded software application, a firmware application, or a combination thereof. One or more databases 708 may be integrated directly into the predictive model system 704 or may be provided separately and/or remotely therefrom, as illustrated. In the case of a remote access to the databases 708 , access may occur via any type of network 706 , as indicated above. The databases 708 may be provided as collections of data or information organized for rapid search and retrieval by a computer. The databases 708 may be structured to facilitate storage, retrieval, modification, and deletion of data in conjunction with various data-processing operations. The databases 708 may consist of a file or sets of files that can be broken down into records, each of which consists of one or more fields. Database information may be retrieved through queries using keywords and sorting commands, in order to rapidly search, rearrange, group, and select the field. The databases 708 may be any organization of data on a data storage medium, such as one or more servers. In one embodiment, the databases 708 are secure web servers and Hypertext Transport Protocol Secure (HTTPS) capable of supporting Transport Layer Security (TLS), which is a protocol used for access to the data. Communications to and from the secure web servers may be secured using Secure Sockets Layer (SSL). Identity verification of a user may be performed using usernames and passwords for all users. Various levels of access rights may be provided to multiple levels of users. Alternatively, any known communication protocols that enable devices within a computer network to exchange information may be used. Examples of protocols are as follows: IP (Internet Protocol), UDP (User Datagram Protocol), TCP (Transmission Control Protocol), DHCP (Dynamic Host Configuration Protocol), HTTP (Hypertext Transfer Protocol), FTP (File Transfer Protocol), Telnet (Telnet Remote Protocol), SSH (Secure Shell Remote Protocol). Referring now to FIG. 8 , the predictive model system 704 illustratively comprises a user interface 802 through which the user may interact with the predictive model system 704 . In particular and as will be discussed in further detail herein below, the user (e.g. a physician) may use the user interface 802 to submit information to the predictive model system 704 . As indicated above, the information may be obtained during the first visit, and comprise basis predictors, such as Cobb angle, type of curvature, and skeletal maturity, as well s 3D morphologic parameters. The user interface 802 may be used to access the information from a memory 806 located locally or remotely from the predictive model system 704 . The predictive model system 704 further comprises a processor 804 , which may be any device that can perform operations on data. Examples are a central processing unit (CPU), a front-end processor, a microprocessor, a graphics processing unit (GPUNPU), a physics processing unit (PPU), a digital signal processor, and a network processor. A plurality of applications 808 a . . . 808 n are illustratively running on the processor 804 for performing operations required at the processor 804 in order to output a predicted final Cobb angle based on the information entered via the user interface 802 . It should be understood that while the applications 808 a . . . 808 n presented herein are illustrated and described as separate entities, they may be combined or separated in a variety of ways. The processor 804 is in communication with memory 806 which may receive and store data. The memory 806 may be a main memory, such as a high speed Random Access Memory (RAM), or an auxiliary storage unit, such as a hard disk or flash memory. The memory 806 may be any other type of memory, such as a Read-Only Memory (ROM), Erasable Programmable Read-Only Memory (EPROM), or optical storage media such as a videodisc and a compact disc. FIG. 9 illustratively represents application 808 a for generating a final Cobb angle prediction. Two-dimensional images of the spine, such as those obtained from radiographic imaging systems or other imaging systems, are provided to a spine reconstruction module 902 . Three-dimensional morphology of the spine is thus provided and a 3D parameters extraction module 904 is configured to receive the 3D data and extract therefrom parameters such as the initial Cobb angle, the plane of maximal deformation, the three-dimensional wedging of vertebral body and disk, the axial intervertebral rotation of the apex, upper and lower junctional level and thoracolumbar level, slenderness, and torsion. These parameters are provided to a modeling unit 906 and combined with the skeletal maturity and curve type parameters to model the progression curve of AIS and output a final Cobb angle prediction value. The output of the predictive model system 704 is an aid to the treating physician to determine if the risk of progression warrants additional treatment. In some embodiments, the predictive model system 704 is further adapted to sketch the curve of progression using the initial Cobb angle and the final Cobb angle. This curve may be output to the user via the user interface 802 or another output device, such as a printer. In some embodiments, the predictive model system 704 is also adapted to select from a series of recommended treatment options as a function of the final Cobb angle and/or the curve of progression generated using the initial and final Cobb angles. The treatment options may be categorized as a function of ranges of final Cobb angles and/or rates of change of the curve of progression such that selection is made of a most appropriate recommended treatment. The selected treatment(s) may then be output to the devices 702 for rendering thereon via the user interface 802 or other output device. Other embodiments for assisting the treating physician with treatment options once the final Cobb angle prediction has been generated will be readily understood by those skilled in the art. While illustrated in the block diagrams as groups of discrete components communicating with each other via distinct data signal connections, it will be understood by those skilled in the art that the present embodiments are provided by a combination of hardware and software components, with some components being implemented by a given function or operation of a hardware or software system, and many of the data paths illustrated being implemented by data communication within a computer application or operating system. The structure illustrated is thus provided for efficiency of teaching the present embodiment. It should be noted that the present invention can be carried out as a method, can be embodied in a system, or on a computer readable medium. The embodiments of the invention described above are intended to be exemplary only. The scope of the invention is therefore intended to be limited solely by the scope of the appended claims.

There is described a system, method, and computer-readable medium having stored thereon executable program code for generating a final Cobb angle prediction for idiopathic scoliosis, the method comprising: receiving patient-specific 3D morphological spine parameters, a selected curve type, and a selected skeletal maturity; applying the patient-specific 3D morphological spine parameters, a selected curve type, and a selected skeletal maturity to a predictive model based on 3D morphological spine parameters, curve type, and skeletal maturity, and generating the final Cobb angle prediction by modeling a progression curve of the idiopathic scoliosis.

This application claims priority to prior Japanese patent application JP 2004-171271, the disclosure of which is incorporated herein by reference. BACKGROUND OF THE INVENTION The present invention relates to a card connector for use in connecting a card and, in particular, to a card connector capable of preventing a card from jumping out when the card is ejected. Japanese Unexamined Patent Application Publication (JP-A) No. 2001-267013 discloses a card connector of a push-push type. The card connector comprises an insulator, a plurality of contacts fixed to the insulator, an eject bar mounted to a frame portion of the insulator, a compression coil spring continuously urging the eject bar in an ejecting direction, and a cam follower guided by a heart cam formed on the eject bar. A card is inserted into the connector and ejected from the connector. When the compression coil spring pushes the eject bar upon ejecting the card, the card may undesirably jump out. In this event, the card is dropped and, in the worst case, damaged. Japanese Unexamined Patent Application Publication (JP-A) No. H6-162281 discloses a connecting structure of an IC card to an external equipment. When the IC card is inserted into the external equipment, the IC card is placed on a sliding plate. The sliding plate is urged by a spring in an ejecting direction. In order to eject the IC card from the external equipment, a push button is pushed. Then, the IC card is released from a connector. The IC card and the sliding plates are ejected from the external equipment under an urging force of the spring. The external equipment adapted to receive the IC card which is inserted therein and ejected therefrom is provided with a braking portion formed adjacent to a card slot at a position under the card slot. The braking portion is formed by a flat rubber plate of synthetic rubber or natural rubber and is fixedly attached by an adhesive. When the sliding plate is ejected from the external equipment, the sliding plate is contacted with the braking portion so that frictional resistance is produced. Therefore, the sliding plate is slowly ejected from the external equipment and the IC card is prevented from jumping out from the external equipment. With the above-mentioned structure, however, the frictional resistance between the sliding plate and the braking portion is unstable and weak. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a card connector which is capable of reliably preventing a card from jumping out when the card is ejected. It is another object of the present invention to provide a card connector of the type described, which has a retarding mechanism for retarding an ejecting operation of the card. Other objects of the present invention will become clear as the description proceeds. According to an aspect of the present invention, there is provided a card connector for use in connecting a card, the card connector comprising a housing for receiving the card, an eject mechanism coupled to the housing for executing an ejecting operation of ejecting the card from the housing, and a retarding mechanism cooperating with the eject mechanism to retard the ejecting operation. BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a front view of a card connector according to a first embodiment of this invention when a card is inserted therein; FIG. 2 is a front view of the card connector in FIG. 1 during ejection of the card; FIG. 3 is front view of the card connector in FIG. 1 after the card is ejected therefrom; FIG. 4 is a view for describing a shape of a heart cam included in the card connector in FIG. 1 ; FIG. 5 is a view for describing an operation of the heart cam of FIG. 4 ; FIG. 6 is a front view of a card connector according to a second embodiment of this invention when a card is inserted therein although not shown in the figure; FIG. 7 is a sectional view taken along a line VII—VII in FIG. 6 ; FIG. 8A is a sectional view of a modification of the card connector of FIG. 6 when the card is inserted therein; and FIG. 8B is a sectional view similar to FIG. 8A when the card is ejected therefrom. DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIGS. 1 to 3 , a card connector according to a first embodiment of the present invention will be described. The card connector depicted at 1 in FIGS. 1 through 3 comprises an insulating housing 2 made of synthetic resin, a plurality of conductive contacts 3 fixed to the housing 2 , an eject bar 4 made of synthetic resin and attached to a frame portion of the housing 2 , a compression coil spring 5 continuously urging the eject bar 4 in an ejecting direction A 1 , and a cam follower 6 having a first end 6 a which is guided by a heart cam 7 formed on the eject bar 4 . A combination of the eject bar 4 , the compression coil spring 5 , the cam follower 6 , and a heart cam 7 is referred to as an eject mechanism 10 . The contacts 3 are arranged in a single row and held inside the housing 2 of the card connector 1 in an area near the center of an inner portion 2 a of the housing 2 . The eject bar 4 is held inside the housing 2 on a left side thereof to be slidable in a vertical direction in the figures. More particularly, the eject bar 4 is contained in the housing 2 to be movable in the ejecting direction A 1 and an inserting direction A 2 opposite to the ejecting direction A 1 . The compression coil spring 5 continuously urges the eject bar 4 towards an inlet portion 2 b of the housing 2 , i.e., in the ejecting direction A 1 . Specifically, the compression coil spring 5 has one end and the other end kept in press contact with the eject bar 4 and an inner surface of the frame portion of the housing 2 , respectively. The cam follower 6 is made of a metal material and has a second end 6 b which is engaged with an axial hole formed on the frame portion of the housing 2 and which is rotatable by a predetermined angle. The first end 6 a of the cam follower 6 is engaged with a groove of the heart cam 7 . A card 11 is inserted into the connector 1 in the inserting direction A 2 and ejected from the connector 1 in the ejecting direction A 1 . The eject bar 4 has a protruding portion 4 b. When the card 11 is inserted into the connector 1 , one corner of a forward end of the card 11 is brought into contact with the protruding portion 4 b. Further, the housing 2 is provided with a rubber brake 8 fixed thereto on a left side of the inlet portion 2 b. The rubber brake 8 is made of an elastically deformable rubber material known in the art. Referring to FIGS. 4 and 5 , the heart cam 7 will briefly be described. The heart cam 7 is formed on a protruding portion 4 c of the eject bar 4 . The heart cam 7 is formed as an annular guide rail or a cam groove having a first point P 1 , a second point P 2 , a third point P 3 , a fourth point P 4 , and a fifth point P 5 . The first point P 1 is a start point of movement of the first end 6 a of the cam follower 6 . The second point P 2 is located in a guide portion slightly inclined with respect to the ejecting and the inserting directions A 1 and A 2 . The third point P 3 is located in a heart-like recessed portion. The fourth point P 4 is located in a guide portion substantially parallel to the ejecting and the inserting directions A 1 and A 2 . The fifth point P 5 is an end point of the movement of the first end 6 a of the cam follower 6 . The fifth point P 5 is identical with the first point P 1 . In a free state of the connector 1 , the first end 6 a of the cam follower 6 is urged rightward in FIG. 4 by elasticity of the cam follower 6 . Following sliding movement of the eject bar 4 , the first end 6 a of the cam follower 6 moves along the heart cam 7 in the order of the first point P 1 , the second point P 2 , the third point P 3 , the fourth point P 4 , and the fifth point P 5 . Depending upon a position of the first end 6 a of the cam follower 6 , the connector 1 is changed from the free state into a mating state and vice versa, as illustrated in FIG. 5 . Turning back to FIGS. 1 to 3 , description will be made of insertion and ejection of the connector 1 into and from the card 11 . When the card 11 is inserted into the housing 2 by operator's fingers, the one corner of the forward end of the card 11 pushes the protruding portion 4 b of the eject bar 4 . Consequently, the eject bar 4 presses the coil spring 5 and slides in the inserting direction A 2 from the inlet portion 2 b towards the inner portion 2 a. Upon completion of insertion of the card 11 , a plurality of contact points (not shown) of the card 11 are connected to the contacts 3 of the card connector 1 . At this time, an operation or movement of the eject bar 4 is restricted by the cam follower 6 . In order to eject the card 11 from the housing 2 , a push button (not shown) formed on the housing 2 or the card 11 itself is pushed. Then, the eject bar 4 is unlocked from the cam follower 6 and slides in the ejecting direction A 1 from the inner portion 2 a towards the inlet portion 2 b under restoring force of the coil spring 5 to reach a state illustrated in FIG. 2 . At this time, the protruding portion 4 b of the eject bar 4 pushes the forward end of the card 11 . Consequently, the card 11 reaches the state illustrated in FIG. 2 together with the eject bar 4 . In this state, one end 4 a of the eject bar 4 starts to compress the rubber brake 8 in a compressing direction, namely, the ejecting and the inserting directions A 1 and A 2 . Subsequently, as illustrated in FIG. 3 , the rubber brake 8 is elastically deformed in a direction perpendicular to the compressing direction so that a butting portion 8 a at an end of a triangular part of the rubber brake 8 is brought into press contact with one side of the card 11 . As a result, the card 11 is braked by friction between the card 11 and the rubber brake 8 . In other words, the rubber brake 8 makes the card 11 be slowed in an ejecting operation thereof. Therefore, the card 11 is prevented from undesirably jumping out from the housing 2 . At this time, the rubber brake 8 serves as a braking mechanism for braking the card 11 or a retarding mechanism for retarding ejection of the card 11 . Preferably, the rubber brake 8 is provided with a hollow portion 8 b. In this event, the rubber brake 8 is easily elastically deformed. At this time, the hollow portion 8 b serves as an auxiliary mechanism for effectively causing elastic deformation of the rubber brake 8 . Referring to FIGS. 6 and 7 , description will be made of a card connector according to a second embodiment of this invention. Similar parts are designated by like reference numerals and description thereof will be omitted. The card connector 1 uses an air spring instead of the rubber brake 8 in the card connector illustrated in FIGS. 1 through 3 . The air spring has a cylindrical portion 27 formed in the housing 2 . The cylindrical portion 27 is provided with an air-relief hole 28 . The air-relief hole 28 allows an inner space of the cylindrical portion 27 to communicate through a rear surface of the housing 2 with an outside. A part of the eject bar 4 is inserted into the cylindrical portion 27 . The air-relief hole 28 has a sectional area extremely narrower than that of the cylindrical portion 27 . With this structure, when the card is ejected from the card connector 1 , air does not easily flow out from the cylindrical portion 27 through the air-relief hole 28 to the outside. Consequently, the eject bar 4 slides slowly. This means that a combination of the cylindrical portion 27 and the air-relief hole 28 serves to make the eject bar 4 be slowed in movement thereof in the ejecting direction A 1 . Accordingly, the card is prevented from undesirably jumping out from the housing 2 . At this time, a combination of the cylindrical portion 27 and the air-relief hole 28 serves as a braking mechanism for braking the eject bar 4 or a retarding mechanism for retarding ejection of the card. As shown in FIGS. 8A and 8B , an air valve 29 may be provided to open and close the air-relief hole 28 . In this case, the air valve 29 is made of an elastically deformable material. When the card is inserted, the eject bar 4 is pushed by the card and moved in the inserting direction A 2 of FIG. 8A . In this event, the air valve 29 opens the air-relief hole 28 as depicted by a lower white arrow 31 in FIG. 8A so that air flows through the air-relief hole 28 into the cylindrical portion 27 . When operation is carried out to eject the card in the manner known in the art, the eject bar 4 slides in the ejecting direction A 1 of FIG. 8B . In this event, air moves in the cylindrical portion 27 towards the air-relief hole 28 to make the air valve 29 be faced to the air-relief hole 28 as depicted by a lower white allow 32 in FIG. 8B . As a consequence, the air is compressed in the cylindrical portion 27 in the ejecting and the inserting directions A 1 and A 2 . Although the air valve 29 faces the air-relief hole 28 , the air is allowed to flow by little and little through the air-relief hole 28 . For example, a small gap is formed between the air valve 29 and the air-relief hole 28 or the air valve 29 is provided with a small hole or holes. Therefore, the eject bar 4 slides slowly and the card is prevented from undesirably jumping out from the housing 2 . While the present invention has thus far been described in connection with the preferred embodiments thereof, it will readily be possible for those skilled in the art to put this invention into practice in various other manners. For example, a plurality of contacts are provided in each of the foregoing embodiments. However, this invention is also applicable to the case where only one contact is provided.

In a card connector for use in connecting a card, an eject mechanism is coupled to a housing for receiving the card. The eject mechanism is for executing an ejecting operation of ejecting the card from the housing. The card connector is provided with a retarding mechanism which cooperates with the eject mechanism to retard the ejecting operation. The retarding mechanism may include a braking mechanism for braking the card in response to an operation of the eject mechanism. Alternatively, the braking mechanism may be for braking an eject bar which is included in the eject mechanism and movable along the housing for ejecting the card.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to the ball type constant velocity joints. In particular, the invention relates to a ball assembly in the form of a sphere divided up into a plurality of rollers (rolling elements) and a common shaft that holds the rollers. The purpose of the invention is to reduce the friction loss and wear of the constant velocity joints. 2. Description of the Prior Art Universal joints (Cardan joint or Hooke joint) have been used for transmitting a driving torque and spin motion from one propeller shaft to another at an arbitrary articulation (joint) angle between the two shafts. Universal joints comprise a cross-shaped spider as a torque-transmitting member, and two Y-shaped end yokes each at end of the shafts. Universal joints lack the constant-velocity characteristic, because the spider is not positioned on a homokinetic plane (bisecting angle plane or constant velocity plane) when the joint is at a non-zero articulation angle. As a result, universal joints suffer from a torsional vibration problem that aggravates as the articulation angle increases. Constant velocity joints solve this problem by offering a virtually zero variation of the spin speed across the input and output shafts. Most of the constant velocity joints use a plurality of torque-transmitting balls that are solid steel spheres. The types of the constant velocity joints that use torque-transmitting balls are the Rzeppa joint [U.S. Pat. No. 2,046,584 filed July 1924 by A. H. Rzeppa], the undercut free joint [U.S. Pat. No. 3,879,960, filed July 1975 by H. Welschof et al], the cross groove joint [U.S. Pat. No. 2,322,570 filed June 1943 by A. Y. Dodge], and the double offset joint [U.S. Pat. No. 1,975,758 filed October 1934 by B. K. Stuber]. Any type of constant velocity joint comprises the inner race (inner joint part), outer race (outer joint part), ball cage (retainer) and the balls. The outer race usually forms a bell-shaped member that comprises a shaft, a base, an aperture and outer ball grooves (tracks) that are machined on its bore surface. The inner race forms a hub that comprises a shaft and inner ball grooves that are machined on its outer surface. The ball cage is positioned between the outer race and the inner race, and comprises circumferentially distributed cage windows (pockets) that hold the balls in the central plane of the ball cage. The inner and outer groove pairs form a special kinematic arrangement that steers (drives) the balls to the homokinetic plane. But constant velocity joints suffer from five distinct disadvantages: 1) they lose some amount of power to sliding friction; 2) the frictional heat could produce high temperature; 3) this high temperature limits the permissible operating speeds and loads; 4) the friction decreases the durability and life of the joints; and 5) the friction, when coupled with a certain operating condition, could lead to a binding (friction lock) problem. See for example, “Universal Joint and Driveshaft Design Manual,” The Society of Automotive Engineers, Inc. 400 Commonwealth Drive, Warrendale, Pa. 15096, ISBN 0-89883-007-9, 1979, pp. 100; and Philip J. Mazziotti, “Dynamic Characteristics of Truck Driveline Systems,” The Eleventh L. Ray Buckendale Lecture, The Society of Automotive Engineers, Inc., SP 262, pp. 21. From the viewpoint of kinematics, the balls of a constant velocity joint cannot have a true rolling condition, because the grooves are not concentric but generally intersect to each other. From the viewpoint of dynamics, each ball is steered (located) to the bisecting plane by the combined action of the inner groove, the outer groove and the cage window. This means that there are at least three contact points on a ball, when a constant velocity joint is spinning under the torque load: the ball to inner groove contact, the ball to outer groove contact, and the ball to cage window contact. Obviously, the ball cannot retain a true rolling condition at all three contact points at the same time. Therefore, some or all of the contact points on a ball cannot but undergo a sliding contact or friction. Previous attempts by others to reduce the friction problem of constant velocity joints have employed special lubricant. These attempts, however, have not proven to completely solve the friction problem, because such measure can only reduce the friction coefficient value. BRIEF SUMMARY OF THE INVENTION It is an object of the present invention to provide torque-transmitting balls for constant velocity joints, while reducing or eliminating the sliding friction of the balls against the surfaces of its mating inner groove, outer groove, and the cage window. The present invention for a “multi-roller” ball provides the foregoing object, and thus offers significant improvements over the prior art. As its name implies, the multi-roller ball assembly has a plurality of sub-rollers, each of which contacts and rolls independently on its mating outer groove and inner groove. None has embodied the concept of the multi-roller ball to cause its each sub-roller to roll independent from each other, and thus to cause the reduction or elimination of the sliding friction problem in constant velocity joints. The multi-roller ball offers the advantages of enabling any ball-type constant velocity joints to have a reduced internal friction loss; to have a smooth articulation and plunge; to have a lower operating temperature; to have an increased durability and life; and to have a higher operating speed and larger torque capacity. The multi-roller ball enjoys these advantages because it has a plurality of sub-rollers rotating independently from each other around a common shaft called the roller shaft. Therefore, in a constant velocity joint receiving a torque load, one sub-roller can roll freely on an outer groove, while another sub-roller rolls on an inner groove. This multi-roller construction relieves the ball assembly from a harmful sliding friction at its rolling contact points. In order to maintain the orientation of the roller shaft along the circumferential direction of the cage window, a slide shaft is provided in such a manner that it can slide along the shaft hole through the axis of the roller shaft and that the lugs at both ends of the slide shaft engage the cage-web grooves that are machined at either sides of the cage webs towards the radial direction. Thus, the multi-roller ball achieves the implementation of the objectives mentioned above in a commercially viable component that is simple and inexpensive enough to be easily applicable to any existing ball-type constant velocity joints. Further objectives and advantages of the multi-roller ball will become apparent from consideration of the drawings and descriptions that follow. Therefore, to the accomplishment of the objectives described above, this invention consists of the features hereinafter illustrated in the drawings, fully described in the detailed description of the preferred embodiments and particularly pointed out in the claims. However, such drawings and descriptions disclose but some of the various ways in which the invention may be practiced. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING FIG. 1 is a perspective view of a prior-art constant velocity joint. FIG. 2 shows a prior-art constant velocity joint under a torque load in a partially enlarged central plane section, illustrating the contact points of a ball against the inner and outer grooves. FIG. 3 is a partially enlarged radial view of a prior-art constant velocity joint, showing the contact between the ball and the cage window (the outer and inner races are not shown). FIG. 4 shows a multi-roller ball assembly in a longitudinal (spin-axis) section, illustrating the assembly of the two half-spherical sub-rollers, the roller shaft, and the slide shaft. FIG. 5 shows a multi-roller ball assembly in a longitudinal (spin-axis) section, revealing the first and second needle bearings disposed between the roller shaft and the two half-spherical sub-rollers. FIGS. 6A and 6B are the front and side views of the half-spherical sub-roller. FIGS. 7A and 7B are the front and side views of the roller shaft. FIG. 8 shows an actual use of a multi-roller ball in a constant velocity joint in a partially enlarged central plane section, revealing the contact points of the half-spherical sub-rollers against the inner and outer grooves. FIG. 9 shows a partially enlarged radial view of my invention in an actual use with a constant velocity joint (the outer and inner races are not shown), revealing the contacts between the slide shaft and the cage. DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings, where like parts are designated throughout with like numerals and symbols, FIGS. 1 through 3 depict a prior art constant velocity joint, presented herein as an illustration of its general construction and inherent problem. A constant velocity joint comprises the outer race (outer joint part) 1 , the inner race (inner joint part) 2 , the cage (retainer) 4 , and the balls 3 . The outer race shaft 5 is either integral to the outer race 1 , or securely connected to the outer race 1 by bolts or splines. The inner-race shaft 6 is typically connected to the inner race 2 by splines and retaining rings. The outer race 1 has a plurality of ball grooves (tracks) 1 a machined on its bore surface, while the inner race 2 has the pairing set of ball grooves (tracks) 2 a machined on its outer circumference surface. The positions of the balls 3 are restrained by the outer grooves 1 a and the inner grooves 2 a . The cage 4 has a plurality of the windows (pockets) 4 a that hold the balls 3 so that all of the balls 3 are located on the central plane of the cage 4 . The combined actions of the outer grooves 1 a , the inner grooves 2 a and the cage windows 4 a steer (locate) the balls 3 towards the constant velocity plane (bisecting-angle plane or homokinetic plane), yielding a constant velocity characteristics at any joint articulation angle. FIG. 2 shows a partially enlarged central-plane section of a prior-art constant velocity joint that is receiving an external torque load 7 , 8 . The driving torque 7 onto the outer race 1 tries to rotate it to the counter-clock-wise direction, while the reaction torque load 8 onto the inner race 2 tries to rotate it to the clock-wise direction, resisting against the motion of the outer race 1 . This action and reaction produce the contact forces 9 , 10 onto the ball 3 . The contact force 9 from the outer groove 1 a to the ball 3 and another contact force 10 from and the inner groove 2 a to ball 3 squeeze the ball 3 . Thus each ball 3 has at least two contact points against its mating inner groove 2 a and the outer groove 1 a. FIG. 3 is a partially enlarged radial view of a prior-art constant velocity joint; showing the contact condition between the cage 4 and the ball 3 . Note that the outer race 1 and the inner race 2 are omitted in FIG. 3 . Typically a cage 4 has a shape of two rings that are bridged together by the cage webs 4 d . In FIG. 3 , the cage window (pocket) 4 a is oriented such that its radial direction 12 c is out-of-paper direction, its tangential or circumferential direction 12 a is to the right-hand side, and its axial direction 12 b is parallel to the cage axis 13 . Each cage window 4 a has two cage flat surfaces 4 e , 4 f and another two web flat surfaces 4 g , 4 h . The distance between the two cage-flat surfaces 4 e , 4 f are generally called the window width. The window width is typically designed to be equal to or slightly larger than the diameter of the ball 3 . One of the main functions of the cage 4 is to push the ball 3 towards the homokinetic plane by generating the contact force 11 against the ball 3 . Thus at any given moment, a ball 3 has at least one contact point against one of the cage flat surfaces 4 e and 4 f . The distance between the two opposing web flat surfaces 4 g , 4 h are generally called the window length. The window length is typically designed to have an enough gap from the ball 3 in order to accommodate any circumferential movement of the balls 3 during the joint articulation. Therefore, each ball 3 of a prior-art constant velocity joint has at least three contact points (forces): The first contact point is against the outer groove 1 a , the second one is against the inner groove 2 a , and the third one is against the cage window 4 a (in other words, the cage flat 4 e or 4 f ). As a result, it is inevitable that the ball 3 undergoes a sliding friction at some or all of the three contact points as the ball 3 is steered to another position. It is well known that this sliding friction could produce many problems such as the friction loss and the friction lock (binding), which could result in the heat generation and eventually the failure of the joint (durability problem). The goal of this invention is to prevent or reduce the friction-induced problems of the conventional ball-type constant velocity joints. This invention solves the problem by replacing the solid balls 3 with the multi-roller balls 20 that make the three contact points of each ball be independent from each other, thus positively eliminating the sliding friction. FIG. 4 shows the longitudinal (spin-axis) section of a multi-roller ball assembly 20 in its preferred embodiment, illustrating the assembled state of its members. A multi-roller ball assembly 20 comprises two substantially half-spherical annular sub-rollers 22 , 23 , the roller shaft 24 , and the slide shaft 35 . In addition to these key components, sliding or needle bearings 33 , 34 for the sub-rollers 22 , 23 may be optionally employed for the enhanced performance as shown in FIG. 5 . Likewise, two retaining rings 29 , 30 may be employed at the either ends of the roller shaft 24 to hold the members together, facilitating the assembly of the multi-roller ball assemblies 20 into a constant velocity joint. The sub-rollers 22 , 23 can spin individually around the roller shaft 24 , allowing them to contact and freely roll on the outer groove 1 a and the inner groove 2 a of a constant velocity joint. The roller shaft 24 serves as a spindle for the sub-rollers 22 , 23 , and the aperture along its axis serves as a sliding guide for the slide shaft 35 . The slide shaft 35 maintains the spin axis orientation of the multi-roller ball 20 relative to the cage window 4 a by engaging its lugs 35 a , 35 b with the webs 4 d as will be explained further in FIGS. 8 and 9 . The slide shaft 35 takes any forces between the multi-roller ball 20 and the cage 4 . In addition, the slide shaft 35 allows the roller shaft 24 to slide longitudinally the slide shaft 35 so that a limited circumferential movement of the multi-roller ball assembly 20 relative to the cage window 4 a is accommodated. Since a multi-roller ball assembly 20 has a first and second sub-rollers 22 , 23 that spin independently from each other, it can positively eliminate or reduce any frictional sliding contact against the outer groove 1 a and the inner groove 2 a. FIGS. 6A and 6B show the front and side views of the sub-roller 22 or 23 . Its center aperture 22 a that comprises the cylindrical bore surface 22 b and the tapered bore surface 22 c rides on the roller shaft 24 directly or via the bearing 27 or 28 . The spherical surface 22 d contacts against the outer race grooves 1 a or inner race grooves 2 a . The inner flat surface 22 e provides a gap against the adjacent sub-roller. The outer flat surface 22 f is intended for reducing the axial length (except the slide shaft 35 ) of the multi-roller ball assembly 20 so that the length of the cage window (the distance between 4 g and 4 h ) can be designed to be shorter. The outer flat surface 14 f can also serve as a thrust surface against the retaining rings 29 , 30 . FIGS. 7A and 7B show the front and side views of the roller shaft 24 . Its cylindrical shaft surface 24 a and the tapered surface 24 b mate onto the bearings 33 , 34 or directly onto the sub-rollers 22 , 23 . The central ridge surface 24 c serves as a transition between the two neighboring tapered surfaces. The aperture 24 d is for the slide shaft 35 that can freely spin within or move along the aperture 24 d . The candidate materials for the roller shaft 24 are a solid metal, an oil-impregnated sintered metal, or any other sliding bearing material FIG. 8 shows an actual use of a multi-roller ball 20 in a constant velocity joint in a partially enlarged central plane section, revealing the contact point of the sub-rollers 22 , 23 against the inner and outer grooves 1 a and 2 a . The multi-roller balls 20 can be used in conjunction with any type of constant velocity joint, except that the cage 4 should have additional cage web grooves 4 i machined to radial direction at each web flat surfaces 4 g and 4 h . The cage web grooves 4 i mate with the ends of the slide shaft 35 , constraining the orientation of each multi-roller ball assembly 20 with respect to the corresponding cage window 4 a . For most of the ball-type constant velocity joints, the inner and outer ends of cage web grooves 4 i are blocked by the outer race bore surface 1 b and the inner race outer surface 2 c . Therefore, the ends of the slide shaft 35 cannot disengage from the cage web grooves 4 i . However, in the case of the cross groove type constant velocity joints, the cage bore side of the cage web grooves 4 i should be closed so that the ends of the slide shaft 35 do not fall to the gap between the cage bore surface 4 b and the inner race outer surface 2 c. FIG. 9 shows a partially enlarged radial view of my invention in actual use with a constant velocity joint (the outer race 1 and inner race 2 are not shown here), revealing the contacts between the ball assembly 20 and the cage 4 . As the cage 4 steers (moves) the multi-roller ball 20 , the cage web grooves 4 i push or pull the ball assembly 20 at the lugs 35 b , 35 c of the slide shaft 35 . From the foregoing it will be apparent that an apparatus and method have been disclosed which are fully capable of carrying out and accomplishing all of the objects and advantages taught by this invention. As many as possible embodiments may be made of the invention without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense. It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and sub-combinations. This is contemplated by and is within the scope of the claims.

A constant velocity joint includes an outer joint member, an inner joint member, torque transmitting ball assemblies guided in pairs of tracks, and a cage having windows for receiving the ball assemblies and cage webs defined between the windows. Each ball assembly comprises a slide shaft having lugs at the ends, a roller shaft rotatably and slidably disposed on the slide shaft, and a first and second annular sub-rollers rotatably disposed on the roller shaft. Each of cage webs includes web grooves formed radially at the circumferential faces, engaging the lugs of the slide shaft, thereby allowing a limited radial movement of the ball assembly relative to the cage window, and transmitting any axial force to and from the ball assembly. The ball assemblies reduce the friction loss and wear of constant velocity joints by providing the sub-rollers that roll independently on the inner or outer tracks.

TECHNICAL FIELD [0001] The present disclosure generally relates to user-manipulable controls in software user interfaces. More specifically it expands upon a tabbed notebook control for switching among various views. BACKGROUND [0002] Tabbing controls are becoming increasingly pervasive in software User Interfaces (UIs). For instance, current-day web browsers such as Internet Explorer® (IE) and Firefox® have recently adding tabbing as a quick and convenient way to switch among open pages. Additionally, version 5.0 of LOTUS NOTES® included Inbox tabbing. Tab controls are also used in more general software applications to switch among views of different properties, etc. A major advantage of tabs is that they consume relatively little screen space, afford the ability to quickly navigate to another panel or view, and can utilize the same screen area to show many different views. [0003] A shortcoming of tabs is that they are used ubiquitously in implementations which lack full user utility. For example, tab relational context doesn't provide a very rich UI structure. Furthermore, the majority of tabs only display text labels. Occasionally a status indicator has been added to a tab. Tab controls typically act as toggles, i.e., the entire tab's surface is a hot spot to click, hiding the contents of the previously active tab and displaying the contents of the tab that the user activates. These controls are toggles because the contents associated with a tab are either visible or hidden. SUMMARY [0004] The essence of this invention is to extend the single-select mutually-exclusive tab concept to include the ability to allow multiple tabs to be active simultaneously, while affording a simple method for the user to do so. The novelty of this invention includes: a. Access to all combinations and permutations of the tab selections. The user can create combined views simply by activating the contents of multiple tabs. This would eliminate the need to create new tabs specifically to represent the combined views of other tabs. The views would be combined in an intelligent way by the software application and this method would differ depending on the application. b. Easy and natural way for user to “drill wider”—to a more end-to-end view as more tabs get selected. Just click another part (multi-select part) of another tab to select that tab to be added to the view. c. In a preferred embodiment, multi tabbing displays and provides access to additional information within the same view but with richer cross-set relationships. [0008] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not necessarily restrictive of the present disclosure. The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate subject matter of the disclosure. Together, the descriptions and the drawings serve to explain the principles of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS [0009] The novelty of the disclosure will be understood by those skilled in the art by reference to the accompanying figures in which: [0010] FIG. 1 is a graphical user interface (GUI) of a current-day tab control illustrating the “Servers” tab being active and showing an error with the blade server in Slot 4 ; [0011] FIG. 2 is a graphical user interface (GUI) of a current-day tab control illustrating the “Storage” tab being active and showing detail about applicable storage. [0012] FIG. 3 is a graphical user interface (GUI) of a preferred embodiment of the present invention illustrating multi select control of the present invention; the contents of the “Servers” tab and the “Storage” tab have been intelligently combined by the application to present the user with a combined view of the two. [0013] FIG. 4 is a graphical user interface (GUI) of a preferred embodiment of the present invention illustrating the utilization of tabs contextually related to each other; [0014] FIG. 5 is a graphical user interface (GUI) of a preferred embodiment of the present invention illustrating the “Servers” tab and “Storage” tab intelligently combined by the application; and [0015] FIG. 6 is a flow diagram of the utilization of multi tabbing of the present invention. DETAILED DESCRIPTION [0016] The present invention provides a method, apparatus and program storage device for multiple active tab functionality integrated into a tabbed view control on a software graphical user interface. One possible embodiment is illustrated in the accompanying drawings. [0017] One embodiment involves troubleshooting hardware problems in a datacenter environment. The current invention would allow the user to combine individual views of hardware into a more integrated and holistic view, affording a better understanding of how individual components relate to one another. [0018] Here is one example. Suppose there is a set of views, implemented in a tab view control that includes a view of servers and a view of storage. In FIG. 1 , it is apparent that there is an error associated the blade server in the 4th slot: “Web_Server — 3”, but the source of the problem remains unclear from this narrow perspective. The user then explores a bit more by clicking on the main part of the “Storage” tab, FIG. 1 (not the top of it, but where the text is). This replaces the previous view with a new view, as is the current art for tab view controls. The user now sees from the storage-only tabbed view that “Pool A” is full ( FIG. 2 ). The user now is wondering how and if “Pool A” relates to the web server blade, like could the problems be correlated? Using this multi-tab invention, the user could select the “Servers” tab in such a way as to NOT replace the “Storage” view. This could be highly surfaced on the tab itself. In the example below it is shown by the top colored bar on the tab, which is the multi-select touch point of the tab. [0019] There are additional embodiments of this type of multi-select control, including but not limited to a check box on the tab, a drop-down selector as part of the tab, or via a right-click context menu choice for multi-tabbing ( FIG. 3 ). [0020] Finally, ( FIG. 4 ) the user could next select the server to get an end-to-end view from the server to the storage and all the nodes in between, made possible and quickly accessible by this invention (one tabbed click from the point of context of either one of the single-select tab cases above, either from “Servers” or from “Storage”). [0021] In a further embodiment of the present invention ( FIG. 5 ), two or more containers may be utilized, each containing multiple tab selectors. For example, a resource- or hardware-based tab group might span a particular dimension, as previously illustrated in FIGS. 1-4 (servers, storage, networking) and a more task-oriented tab group could span another. It would be possible to simultaneously activate or select a single tab in each container, thus creating a combined view in that manner. So, for example, the task-oriented tabs might have tabs for “Events”, “Health”, “Troubleshoot”, and the like. If properly designed, such a UI could surface fewer navigation nodes to the user than traditional UIs, and the task-oriented tabs matrixed with the resource-oriented tabs complement each other. [0022] Referring to FIG. 6 , a method for providing a user interface 100 is depicted. Method 100 may define a first view comprising a representation of a first set of information, the first view displayable via the user interface 110 . Method 100 may associate the first view with a first tab of the user interface 120 . Method 100 may define a second view comprising a representation of a second set of information, the second view displayable via the user interface 130 . Method 100 may associate the second view with a second tab of the user interface 140 . Method 100 may receive a selection from the user via the user interface, the selection comprising at least the first tab and the second tab 150 . Method 100 may define a third view comprising a representation of at least a portion of the first set of information and at least a portion of the second set of information 160 . Method 100 may display the third view in response to the selection of at least the first tab and the second tab 170 . [0023] This invention is applicable beyond the server-storage examples described above. Multi-select tabbing could also be used for map applications, with tabs for “Roads”, “Satellite”, and “Terrain”. Users could pick and choose one of more map tabs based on which map “layers” were most useful to them, and not have screen-wasteful and complicating “Hybrid” tabs to do that function. Another example would be for network management, with tabs for “Image”, “Tabular”, and “node-link”. Again, users could pick one or more tabs, with for example the “Tabular”+“node-link” tabs being selected could show a hybrid view of a node-link topology view intermixed with embedded mini tabular displays for particular nodes (e.g., event table, attribute-value table). In this network management tabbing example the multi-tabbing is not a simple layering as in the map example. The combination of multiple tabs presents information that's optimized for the multi-selection and how best to server the needs of the user. [0024] In the present disclosure, the methods disclosed may be implemented as sets of instructions or software readable by a device. Further, it is understood that the specific order or hierarchy of steps in the methods disclosed are examples of exemplary approaches. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the method can be rearranged while remaining within the disclosed subject matter. The accompanying method claims present elements of the various steps in a sample order, and are not necessarily meant to be limited to the specific order or hierarchy presented. [0025] It is believed that the present disclosure and many of its attendant advantages will be understood by the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the components without departing from the disclosed subject matter or without sacrificing all of its material advantages. The form described is merely explanatory, and it is the intention of the following claims to encompass and include such changes.

A method for extending known single-select mutually-exclusive tabs to simultaneously include multiple selection tabs with easy surfaced user controls. These controls enable the user to quickly and easily select and unselect one or more tabs in the tab group.

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of priority from Taiwan patent application TW 103 124 194, filed Jul. 14, 2014, the contents of which are herein incorporated by reference. BACKGROUND OF THE INVENTION [0002] The present invention relates to a pulley for an alternator, and in particular, to a pulley for an automotive alternator. [0003] An alternator is a type of generator that can produce an alternating current by converting mechanical energy into electrical energy. An automotive alternator converts mechanical energy of an engine into electrical energy to charge a battery, so as to supply electrical power to other electrical appliances on the automobile, and start a motor to rotate the engine. [0004] An alternator generally has an annular stator and a rotor received in the annular stator. A wire is wound on the stator, and the rotor rotates rapidly in the stator so that the wire moves relative to a magnetic field generated by the rotor, and an induced electromotive force (voltage) is generated in the wire. [0005] An automotive alternator is usually utilized by an engine driving a belt. The belt is wound on a pulley, and the pulley is connected to a rotor so as to drive the rotor to rotate. However, in conventional alternator design, when an engine starts, or accelerates or decelerates quickly in an instant, a waveform changes significantly at the moment the generator charges a battery, and it cannot be stabilized. In addition, one side of the belt wound on the pulley is tight, and the other side thereof is slack. The tension of the slack-side belt is low, and therefore a tensioner is disposed thereon to adjust the tension of the belt. However, when a rotation speed at which the engine transmits power changes suddenly, because the pulley of the generator is locked by a nut and the belt is made of a flexible material and cannot reflect the rotation speed immediately, a slip is easily caused between the belt and the pulley. Moreover, the fluctuation of the rotation speed causes the belt to bear not only a repeated stress but also a centrifugal force that is applied on the belt when the pulley rotates. The value of the centrifugal force changes with the rotation speed, and therefore the belt is often affected by adverse factors of an internal micro tension, which pulls the belt, and external large-amplitude shaking. SUMMARY [0006] The present invention provides a pulley for an alternator, which includes an outer wheel, provided with an axle hole at the center; a clutch wheel, fixedly disposed in the axle hole of the outer wheel and having a pivot hole; a hollow connecting shaft, having a first end and a second end, where the first end is rotatably disposed in the pivot hole of the clutch wheel, so that the hollow connecting shaft maintains a co-rotational relationship with the outer wheel in a first relative rotation direction by means of the clutch wheel, while in a second relative rotation direction, the hollow connecting shaft is disassociated from the co-rotational relationship with the outer wheel, and presents an idling state; and the second end of the hollow connecting shaft is provided with a first protruding portion; a hollow core shaft, having a first end and a second end, where the hollow core shaft is rotatably received in the outer wheel, and the second end of the hollow core shaft is rotatably arranged at the second end of the hollow connecting shaft; the second end of the hollow core shaft is provided with a second protruding portion, and the second protruding portion corresponds to the first protruding portion; the number of one of the first protruding portion and the second protruding portion is at least one, and the number of the other of the first protruding portion and the second protruding portion is at least two; and an elastic element, disposed between the second end of the hollow connecting shaft and the second end of the hollow core shaft. [0007] When an external force drives the outer wheel to rotate, the outer wheel rotates relative to the hollow connecting shaft in the first relative rotation direction, and drives, through the clutch wheel, the hollow connecting shaft to rotate synchronously; the second end of the hollow connecting shaft presses the elastic element, and while being pressed, the elastic element pushes the second end of the hollow core shaft, thereby driving the hollow core shaft to rotate; and if a rotation angle of the hollow connecting shaft relative to the hollow core shaft exceeds a predetermined value at this time, the first protruding portion of the hollow connecting shaft contacts the second protruding portion of the hollow core shaft, thereby stopping relative rotation between the hollow connecting shaft and the hollow core shaft, so as to prevent the elastic element from being pressed excessively, and to set the hollow connecting shaft and the hollow core shaft in a synchronous co-rotational relationship. When the external force decreases or stops driving the outer wheel to rotate, the hollow core shaft continues to rotate due to inertia, and stretches the elastic element, and while being stretched, the elastic element pulls the second end of the hollow connecting shaft, thereby driving the hollow connecting shaft to rotate relative to the outer wheel in the second relative rotation direction, so that the hollow connecting shaft is disassociated from the co-rotational relationship with the outer wheel, and idles in the clutch wheel; and if a rotation angle of the hollow connecting shaft relative to the hollow core shaft exceeds a predetermined value at this time, the first protruding portion of the hollow connecting shaft contacts the second protruding portion of the hollow core shaft, thereby stopping relative rotation between the hollow connecting shaft and the hollow core shaft, so as to prevent the elastic element from being stretched excessively, and to set the hollow connecting shaft and the hollow core shaft in a synchronous co-rotational relationship. [0008] According to another preferred embodiment of the present invention, the hollow core shaft passes through the hollow connecting shaft, and the first end of the hollow core shaft protrudes from the first end of the hollow connecting shaft; a tight-fit component is sleeved over an outer circumferential wall surface of the first end of the hollow core shaft in a tight-fit manner, and the tight-fit component is also tightly fit with an end surface of the first end of the hollow connecting shaft; therefore, the hollow connecting shaft and the hollow core shaft are made to corotate coaxially under a friction between the tight-fit component and the hollow connecting shaft and a friction between the tight-fit component and the hollow core shaft, and when the external force decreases or stops driving the outer wheel to rotate, the hollow core shaft continues to rotate due to inertia, and drives, through the tight-fit component, the hollow connecting shaft to rotate relative to the outer wheel in the second relative rotation direction, so that the hollow connecting shaft is disassociated from the co-rotational relationship with the outer wheel and idles in the clutch wheel. [0009] According to another preferred embodiment of the present invention, the tight-fit component is a C-shaped retaining ring. [0010] According to another preferred embodiment of the present invention, a first ball bearing is sleeved over the first end of the hollow core shaft, a second ball bearing is sleeved over the second end of the hollow core shaft, and the first ball bearing and the second ball bearing are disposed between the hollow core shaft and the outer wheel, so that the hollow core shaft is rotatable relative to the outer wheel. [0011] According to another preferred embodiment of the present invention, three grooves are provided in a concave manner on an inner circumferential wall surface of the outer wheel, and an anaerobic adhesive is coated in the grooves, so that the clutch wheel, the first ball bearing, and the second ball bearing are separately tightly fit in the grooves, and are fixedly glued in the outer wheel by using the anaerobic adhesive. [0012] According to another preferred embodiment of the present invention, a positioning casing is further sleeved over the first ball bearing, and an axial position of the pulley on the alternator is limited by the positioning casing. [0013] According to another preferred embodiment of the present invention, an outer circumferential wall surface of the outer wheel is provided with a belt groove, for a belt to be wound on. [0014] According to another preferred embodiment of the present invention, the belt is connected to a mechanical energy generating source, and the mechanical energy generating source provides an external force to drive the belt, thereby driving the outer wheel to rotate. [0015] According to another preferred embodiment of the present invention, the mechanical energy generating source is an engine. [0016] According to another preferred embodiment of the present invention, an inner circumferential wall surface of the hollow core shaft is provided with a threaded surface, the threaded surface is screwed with a joint lever having corresponding threads, and the joint lever is connected to a rotor, so that the hollow core shaft and the rotor corotate synchronously. [0017] According to another preferred embodiment of the present invention, an inner circumferential wall surface of the outer wheel is provided with a step portion, for the clutch wheel to abut against, thereby limiting an axial displacement of the clutch wheel. [0018] According to another preferred embodiment of the present invention, one end of the clutch wheel is provided with a positioning member, to limit an axial position of the clutch wheel, and the positioning member is a C-shaped retaining ring. [0019] According to another preferred embodiment of the present invention, the elastic element is a torque spring, and a wire profile of the torque spring is circular, elliptical, or rectangular. [0020] According to another preferred embodiment of the present invention, when the wire profile of the torque spring is rectangular, two end surfaces of the torque spring are grinded, so as to enhance axial positioning of the torque spring and control a free length of the torque spring more precisely. [0021] According to another preferred embodiment of the present invention, two sides of the clutch wheel are each provided with an oil seal element, so as to prevent liquid in the clutch wheel from flowing into the outer wheel. [0022] According to another preferred embodiment of the present invention, one side of one of the oil seal elements is provided with a positioning member, and the positioning member is sleeved over an inner side wall surface of the outer wheel in a tight-fit manner, to limit axial positions of the oil seal elements. [0023] According to another preferred embodiment of the present invention, the positioning member is a C-shaped retaining ring. [0024] According to another preferred embodiment of the present invention, an end, corresponding to the second end of the hollow core shaft, of the outer wheel is arranged with a dust cover, so as to prevent external dust from entering the outer wheel. [0025] The present invention further provides a pulley for an alternator, which includes an outer wheel, provided with an axle hole at the center; a clutch wheel, fixedly disposed in the axle hole of the outer wheel and having a pivot hole; a hollow connecting shaft, having a first end and a second end, where the first end is rotatably disposed in the pivot hole of the clutch wheel, so that the hollow connecting shaft maintains a co-rotational relationship with the outer wheel in a first relative rotation direction by means of the clutch wheel, while in a second relative rotation direction, the hollow connecting shaft is disassociated from the co-rotational relationship with the outer wheel, and presents an idling state; and the second end of the hollow connecting shaft is provided with a first protruding portion; a hollow core shaft, having a first end and a second end, where the hollow core shaft is rotatably received in the outer wheel, and the hollow core shaft passes through the hollow connecting shaft; the first end of the hollow core shaft protrudes from the first end of the hollow connecting shaft, and the second end of the hollow core shaft is rotatably arranged on the second end of the hollow connecting shaft; the second end of the hollow core shaft is provided with a second protruding portion, and the second protruding portion corresponds to the first protruding portion; the number of one of the first protruding portion and the second protruding portion is at least one, and the number of the other of the first protruding portion and the second protruding portion is at least two; an elastic element, disposed between the second end of the hollow connecting shaft and the second end of the hollow core shaft; and a tight-fit component, sleeved over an outer circumferential wall surface of the first end of the hollow core shaft in a tight-fit manner and tightly fit with an end surface of the first end of the hollow connecting shaft, so that the hollow connecting shaft and the hollow core shaft corotate coaxially under a friction between the tight-fit component and the hollow connecting shaft and a friction between the tight-fit component and the hollow core shaft. [0026] When an external force drives the outer wheel to rotate, the outer wheel rotates relative to the hollow connecting shaft in the first relative rotation direction, and drives, through the clutch wheel, the hollow connecting shaft to rotate synchronously, and the hollow connecting shaft drives, through the tight-fit component, the hollow core shaft to rotate; if the friction provided by the tight-fit component is insufficient to drive the hollow core shaft to rotate at this time, the second end of the hollow connecting shaft presses the elastic element, and while being pressed, the elastic element pushes the second end of the hollow core shaft, thereby driving the hollow core shaft to rotate; and if a rotation angle of the hollow connecting shaft relative to the hollow core shaft exceeds a predetermined value at this time, the first protruding portion of the hollow connecting shaft contacts the second protruding portion of the hollow core shaft, thereby stopping relative rotation between the hollow connecting shaft and the hollow core shaft, so as to prevent the elastic element from being pressed excessively, and to set the hollow connecting shaft and the hollow core shaft in a synchronous co-rotational relationship. When the external force decreases or stops driving the outer wheel to rotate, the hollow core shaft continues to rotate due to inertia, and drives, through the tight-fit component, the hollow connecting shaft to rotate relative to the outer wheel in the second relative rotation direction; and if the friction provided by the tight-fit component is insufficient to drive the hollow connecting shaft to rotate at this time, the hollow core shaft rotates relative to the hollow connecting shaft until the first protruding portion of the hollow connecting shaft contacts the second protruding portion of the hollow core shaft, thereby stopping relative rotation between the hollow connecting shaft and the hollow core shaft, and setting the hollow connecting shaft and the hollow core shaft in a synchronous co-rotational relationship. [0027] According to another preferred embodiment of the present invention, when the external force decreases or stops driving the outer wheel to rotate, the hollow core shaft continues to rotate due to inertia, and drives, through the tight-fit component, the hollow connecting shaft to rotate relative to the outer wheel in the second relative rotation direction; if the friction provided by the tight-fit component is insufficient to drive the hollow connecting shaft to rotate at this time, the hollow core shaft stretches the elastic element, and while being stretched, the elastic element pulls the second end of the hollow connecting shaft, thereby driving the hollow connecting shaft to rotate relative to the outer wheel in the second relative rotation direction, so that the hollow connecting shaft is disassociated from the co-rotational relationship with the outer wheel; and if a rotation angle of the hollow connecting shaft relative to the hollow core shaft exceeds a predetermined value, the protruding portion of the hollow connecting shaft contacts the protruding portion of the hollow core shaft, thereby stopping relative rotation between the hollow connecting shaft and the hollow core shaft, so as to prevent the elastic element from being stretched excessively, and to set the hollow connecting shaft and the hollow core shaft in a synchronous co-rotational relationship. [0028] According to another preferred embodiment of the present invention, the tight-fit component is a C-shaped retaining ring. [0029] According to another preferred embodiment of the present invention, a first ball bearing is sleeved over the first end of the hollow core shaft, a second ball bearing is sleeved over the second end of the hollow core shaft, and the first ball bearing and the second ball bearing are disposed between the hollow core shaft and the outer wheel, so that the hollow core shaft is rotatable relative to the outer wheel. [0030] According to another preferred embodiment of the present invention, three grooves are provided in a concave manner on an inner circumferential wall surface of the outer wheel, and an anaerobic adhesive is coated in the grooves, so that the clutch wheel, the first ball bearing, and the second ball bearing are separately tightly fit in the grooves, and are fixedly glued in the outer wheel by using the anaerobic adhesive. [0031] According to another preferred embodiment of the present invention, a positioning casing is further sleeved over the first ball bearing, and an axial position of the pulley on the alternator is limited by the positioning casing. [0032] According to another preferred embodiment of the present invention, an outer circumferential wall surface of the outer wheel is provided with a belt groove, for a belt to be wound on. [0033] According to another preferred embodiment of the present invention, the belt is connected to a mechanical energy generating source, and the mechanical energy generating source provides an external force to drive the belt, thereby driving the outer wheel to rotate. [0034] According to another preferred embodiment of the present invention, the mechanical energy generating source is an engine. [0035] According to another preferred embodiment of the present invention, an inner circumferential wall surface of the hollow core shaft is provided with a threaded surface, the threaded surface is screwed with a joint lever having corresponding threads, and the joint lever is connected to a rotor, so that the hollow core shaft and the rotor corotate synchronously. [0036] According to another preferred embodiment of the present invention, an inner circumferential wall surface of the outer wheel is provided with a step portion, for the clutch wheel to abut against, thereby limiting an axial displacement of the clutch wheel. [0037] According to another preferred embodiment of the present invention, one end of the clutch wheel is provided with a positioning member, to limit an axial position of the clutch wheel, and the positioning member is a C-shaped retaining ring. [0038] According to another preferred embodiment of the present invention, the elastic element is a torque spring, and a wire profile of the torque spring is circular, elliptical, or rectangular. [0039] According to another preferred embodiment of the present invention, when the wire profile of the torque spring is rectangular, two end surfaces of the torque spring are grinded, so as to enhance axial positioning of the torque spring and control a free length of the torque spring more precisely. [0040] According to another preferred embodiment of the present invention, two sides of the clutch wheel are each provided with an oil seal element, so as to prevent liquid in the clutch wheel from flowing into the outer wheel. [0041] According to another preferred embodiment of the present invention, one side of one of the oil seal elements is provided with a positioning member, and the positioning member is sleeved over an inner side wall surface of the outer wheel in a tight-fit manner, to limit axial positions of the oil seal elements. [0042] According to another preferred embodiment of the present invention, the positioning member is a C-shaped retaining ring. [0043] According to another preferred embodiment of the present invention, an end, corresponding to the second end of the hollow core shaft, of the outer wheel is arranged with a dust cover, so as to prevent external dust from entering the outer wheel. [0044] The present invention further provides an alternator having the pulley according to the present invention. [0045] According to another preferred embodiment of the present invention, the alternator is used on a vehicle. [0046] For better understanding of the detailed description of the present invention, the features and technical advantages of the present invention are described generally above. The following describes the additional features and advantages of the present invention. Persons skilled in the art should be aware that the disclosed concept and specific implementation manner can be easily used as a basis for modifying or designing other structures for implementing objectives the same as the present invention. Persons skilled in the art should also be aware that such equivalent structures do not depart from the spirit and scope of the present invention which are claimed in the patent application scope. BRIEF DESCRIPTION OF THE DRAWINGS [0047] For a more thorough understanding of the present invention and advantages of the present invention, the following descriptions are provided with reference to the accompanying drawings, where: [0048] FIG. 1 is a three-dimensional exploded view of a pulley for an alternator according to the present invention; [0049] FIG. 2 is a sectional assembled view of a pulley for an alternator according to the present invention; [0050] FIG. 3 is a schematic structural view of a hollow connecting shaft according to the present invention; [0051] FIG. 4 is a schematic structural view of a hollow core shaft according to the present invention; and [0052] FIG. 5 is a schematic view of a rotor of an alternator according to the present invention. MEANING OF REFERENCE NUMERALS [0000] 10 Pulley 20 Joint lever 30 Rotor 110 Outer wheel 111 Axle hole 112 Belt groove 113 Step portion 120 Clutch wheel 121 Pivot hole 122 Housing 123 Rolling member 124 Elastic member 125 Cap 130 Hollow connecting shaft 131 First end of the hollow connecting shaft 132 Second end of the hollow connecting shaft 133 First protruding portion 134 Stop wall of the hollow connecting shaft 140 Hollow core shaft 141 First end of the hollow core shaft 142 Second end of the hollow core shaft 143 First ball bearing 144 Second ball bearing 145 Protruding ring of the hollow core shaft 146 Second protruding portion 147 Stop wall of the hollow core shaft 148 Threaded surface 150 Elastic element 160 Tight-fit component 161 Positioning gasket 162 C-shaped retaining ring 170 Positioning casing 171 Protruding ring of the positioning casing 181 Oil seal element 182 Oil seal element 183 Positioning member 184 Dust cover 185 Positioning member DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS [0091] The following embodiments describe the present invention in further detail. The embodiments are merely used to describe the present invention and illustrate the advantages of specific embodiments of the present invention, but it does not mean that the present invention is limited to such implementations. [0092] FIG. 1 and FIG. 2 are respectively a three-dimensional exploded view and a sectional assembled view of a pulley for an alternator according to the present invention. As shown in FIG. 1 and FIG. 2 , a pulley 10 for an alternator according to the present invention mainly includes an outer wheel 110 , a clutch wheel 120 , a hollow connecting shaft 130 , a hollow core shaft 140 , an elastic element 150 , and a tight-fit component 160 . The outer wheel 110 is a wheel-shaped member provided with an axle hole 111 at the center, and is provided with a belt groove 112 on an outer circumferential wall surface thereof and a step portion 113 on an inner circumferential wall surface thereof. The clutch wheel 120 is annular, provided with a pivot hole 121 at the center, and fixedly disposed in the axle hole 111 of the outer wheel 110 . For example, a groove may be provided in a concave manner on the inner circumferential wall surface of the outer wheel 110 , and an anaerobic adhesive is coated in the groove so that the clutch wheel 120 can be fixedly connected to an inner circumferential wall surface of the axle hole 111 of the outer wheel 110 by means of tight fit and adhesion of the anaerobic adhesive. One end of the clutch wheel 120 abuts against the step portion 113 of the outer wheel 110 to limit an axial position of the clutch wheel 120 and to ensure that an end surface of the clutch wheel 120 is perpendicular to the hollow connecting shaft 130 and the hollow core shaft 140 , prevent axial displacement of the clutch wheel 120 during high-speed rotation, and moreover, provide an axial positioning reference during assembly of components in the outer wheel 110 , which facilitates positioning during the assembly. [0093] The hollow connecting shaft 130 has a first end 131 and a second end 132 . The first end 131 is rotatably disposed in the clutch wheel 120 so that the hollow connecting shaft 130 can maintain a co-rotational relationship with the outer wheel 110 in a first relative rotation direction by means of the clutch wheel 120 (for example, the hollow connecting shaft 130 rotates anticlockwise relative to the outer wheel 110 ), and it is disassociated from the co-rotational relationship with the outer wheel 110 in a second relative rotation direction to enter an idling state (for example, the hollow connecting shaft 130 rotates clockwise relative to the outer wheel 110 ), and at this time, the hollow connecting shaft 130 rotates independently of the outer wheel 110 . The hollow connecting shaft 130 is provided with a first protruding portion 133 on the second end 132 , as shown in FIG. 3 . [0094] In a preferred embodiment of the present invention, the clutch wheel 120 has a housing 122 , a plurality of rolling members 123 , a plurality of elastic members 124 , and two caps 125 . The clutch wheel 120 is provided with a positioning member 185 on an end opposite to the end abutting against the step portion 113 to limit the axial position of the clutch wheel 120 and prevent the caps 125 of the clutch wheel 120 from falling off. The positioning member may be a C-shaped retaining ring. For the detailed structure and operating principle of the clutch wheel 120 , reference may be made to Taiwan Patent Application No. 098129945 filed by the applicant on Sep. 4, 2009. However, the clutch wheel of the present invention is not limited thereto, and any speed-difference clutch apparatus capable of implementing the functions of the clutch wheel 120 described in the present invention may be designed as the clutch wheel 120 of the present invention. Moreover, in the present invention, two ends of the clutch wheel 120 are each provided with an oil seal element 181 / 182 so as to prevent a liquid (for example, a lubricating oil) in the clutch wheel 120 from permeating and polluting the interior of the pulley 10 . Furthermore, a positioning member 183 may be sleeved over one side of the oil seal element 182 . The positioning member 183 may be a C-shaped retaining ring, and may be sleeved over an inner side wall surface of the outer wheel 110 in a tight-fit manner, to limit axial positions of the oil seal elements 181 and 182 and the clutch wheel 120 . [0095] The hollow core shaft 140 is disposed in the outer wheel 110 and has a first end 141 and a second end 142 . A first ball bearing 143 is sleeved over the first end 141 , and a second ball bearing 144 is sleeved over the second end 142 . The first ball bearing 143 and the second ball bearing 144 are both fixedly connected to the inner circumferential wall surface of the outer wheel 110 (for example, the outer wheel 110 may be provided with two grooves on the inner circumferential wall surface in a concave manner, and an anaerobic adhesive is coated in the grooves so that the first ball bearing 143 and the second ball bearing 144 can be fixedly connected to the inner circumferential wall surface of the axle hole 111 of the outer wheel 110 by means of tight fit and adhesion of the anaerobic adhesive) so that the hollow core shaft 140 is rotatable relative to the outer wheel 110 . In addition, the hollow core shaft 140 passes through the hollow connecting shaft 130 , and the first end 141 of the hollow core shaft 140 protrudes from the first end 131 of the hollow connecting shaft 130 . A protruding ring 145 is annularly arranged at the second end 142 of the hollow core shaft 140 . The protruding ring 145 is rotatably arranged on the second end 132 of the hollow connecting shaft 130 . A second protruding portion 146 is provided in a protruding manner in a direction towards the hollow connecting shaft 130 , and the second protruding portion 146 corresponds to the first protruding portion 133 so that after the hollow connecting shaft 130 and the hollow core shaft 140 rotate by a particular degree relative to each other, the first protruding portion 133 of the hollow connecting shaft 130 contacts the second protruding portion 146 of the hollow core shaft 140 , thereby stopping relative rotation between the hollow connecting shaft 130 and the hollow core shaft 140 . For example, when the hollow connecting shaft 130 is provided with two first protruding portions 133 at the second end 132 , and when the hollow core shaft 140 is provided with three second protruding portions 146 at the second end 142 , the hollow core shaft 140 can only rotate clockwise or anticlockwise by 120 degrees relative to the hollow connecting shaft 130 after being sleeved over the hollow connecting shaft 130 because relative rotation between the hollow connecting shaft 130 and the hollow core shaft 140 is stopped when the first protruding portions 133 contact the second protruding portions 146 . [0096] The elastic element 150 is disposed between the second end 132 of the hollow connecting shaft 130 and the second end 142 of the hollow core shaft 140 . In a preferred embodiment of the present invention, the elastic element is a torque spring, and a wire profile of the torque spring may be circular, elliptical, or rectangular. When the wire profile of the torque spring is rectangular, two end surfaces of the torque spring may be grinded so as to enhance an axial positioning capability of the torque spring and control a free length of the spring more precisely. The hollow connecting shaft 130 is provided with a stop wall 134 in a concave manner on an inner circumferential wall surface of the second end 132 (as shown in FIG. 3 ) so that one end of the elastic element 150 can abut against the stop wall 134 , and the elastic element 150 may also be fixedly connected to the stop wall 134 . In addition, The hollow core shaft 140 is also provided with a stop wall 147 on an inner side of the protruding ring 145 of the second end 142 (as shown in FIG. 4 ) so that the other end of the elastic element 150 can abut against the stop wall 147 , and the elastic element 150 may also be fixedly connected to the stop wall 147 . When the two ends of the elastic element 150 are fixedly connected to the stop wall 134 of the hollow connecting shaft 130 and the stop wall 147 of the hollow core shaft 140 , relative rotation between the hollow connecting shaft 130 and the hollow core shaft 140 presses or stretches the elastic element 150 ; when the two ends of the elastic element 150 merely abut against but are not fixedly connected to the stop wall 134 of the hollow connecting shaft 130 or the stop wall 147 of the hollow core shaft 140 , relative rotation between the hollow connecting shaft 130 and the hollow core shaft 140 only presses the elastic element 150 . [0097] The tight-fit component 160 is a C-shaped retaining ring; the C-shaped retaining ring is sleeved over the outer circumferential wall surface of the first end 141 of the hollow core shaft 140 in a tight-fit manner, and is tightly fit with a tail end surface of the first end 131 of the hollow connecting shaft 130 . Therefore, under a friction between the tight-fit component 160 and the end surface of the first end 131 of the hollow connecting shaft 130 and a friction between the tight-fit component 160 and the outer circumferential wall surface of the first end 141 of the hollow core shaft 140 , the hollow connecting shaft 130 and the hollow core shaft 140 drive each other and corotate coaxially, as shown in FIG. 3 . [0098] A positioning casing 170 is further sleeved over the first ball bearing 143 , and the positioning casing 170 is a hollow annular pipe provided with a protruding ring 171 at one end; therefore, the protruding ring 171 penetrates the first ball bearing 143 and provides an abutting and cushioning function when the pulley 10 is installed on an alternator, and an axial position of the pulley 10 on the alternator is limited by the positioning casing 170 . [0099] The hollow core shaft 140 is provided with a threaded surface 148 on an inner circumferential wall surface thereof, the threaded surface 148 may be screwed with a joint lever 20 having corresponding threads, and the joint lever 20 is connected to a rotor 30 of the alternator so that the hollow core shaft 140 and the rotor 30 corotate synchronously (as shown in FIG. 5 ). In addition, an end, corresponding to the second end 142 of the hollow core shaft 140 , of the outer wheel 110 is arranged with a dust cover 184 so as to prevent external dust from entering the outer wheel 110 . [0100] With the structure described above, when a mechanical energy generating source provides an external force to drive the outer wheel 110 to rotate, the outer wheel 110 rotates relative to the hollow connecting shaft 130 in the first relative rotation direction and drives, through the clutch wheel 120 , the hollow connecting shaft 130 to rotate synchronously, and with the friction provided by the tight-fit component 160 , the hollow connecting shaft 130 drives the hollow core shaft 140 to rotate. At this time, if the friction provided by the tight-fit component 160 is insufficient to drive the hollow core shaft 140 to rotate, the hollow connecting shaft 130 rotates relative to the hollow core shaft 140 , which causes the stop wall 134 at the second end 132 of the hollow connecting shaft 130 to press the elastic element 150 , and while being pressed, the elastic element 150 pushes the stop wall 147 at the second end 142 of the hollow core shaft 140 , thereby driving the hollow core shaft 140 to rotate. At this time, if a relative rotation angle between the hollow connecting shaft 130 and the hollow core shaft 140 exceeds a predetermined value (for example, 120 degrees), the first protruding portion 133 of the hollow connecting shaft 130 contacts the second protruding portion 146 of the hollow core shaft 140 , thereby stopping relative rotation between the hollow connecting shaft 130 and the hollow core shaft 140 so as to avoid pressing the elastic element 150 excessively and damaging the structure thereof, and to set the hollow connecting shaft 130 and the hollow core shaft 140 in a synchronous co-rotational relationship; the hollow core shaft 140 also drives the rotor 30 to rotate so that the alternator generates an induced current. [0101] In addition, if the outer wheel 110 is originally in a rotation state, when the mechanical energy generating source provides an external force to accelerate the rotation of the outer wheel 110 , an operating principle of the pulley 10 of the present invention is substantially the same as the aforementioned operating principle in the case of starting the outer wheel 110 to rotate, and therefore it is not repeated herein. [0102] On the contrary, when the external force stops driving the outer wheel 110 to rotate, the hollow core shaft 140 continues to rotate due to inertia of the rotor 30 . At this time, the hollow core shaft 140 drives, by using the friction provided by the tight-fit component 160 , the hollow connecting shaft 130 to rotate relative to the outer wheel 110 in the second relative rotation direction so that the hollow connecting shaft 130 is disassociated from the co-rotational relationship with the outer wheel 110 . At this time, if the friction provided by the tight-fit component 160 is insufficient to drive the hollow connecting shaft 130 to rotate, the hollow core shaft 140 rotates relative to the hollow connecting shaft 130 ; if the elastic element 150 merely abuts against but is not fixedly connected to the hollow connecting shaft 130 and the hollow core shaft 140 , the hollow core shaft 140 keeps rotating relative to the hollow connecting shaft 130 until the second protruding portion 146 of the hollow core shaft 140 contacts the first protruding portion 133 of the hollow connecting shaft 130 , thereby stopping relative rotation between the hollow connecting shaft 130 and the hollow core shaft 140 and setting the hollow connecting shaft 130 and the hollow core shaft 140 in a synchronous co-rotational relationship so that the hollow connecting shaft 130 and the hollow core shaft 140 rotate relative to the outer wheel 110 in the second relative rotation direction. [0103] If the elastic element 150 is fixedly connected to the hollow connecting shaft 130 and the hollow core shaft 140 , when the friction provided by the tight-fit component 160 is insufficient to drive the hollow connecting shaft 130 to rotate, the hollow core shaft 140 rotates relative to the hollow connecting shaft 130 and stretches the elastic element 150 , and while being stretched, the elastic element 150 pulls the second end 132 of the hollow connecting shaft 130 , thereby driving the hollow connecting shaft 130 to rotate relative to the outer wheel 110 in the second relative rotation direction so that the hollow connecting shaft 130 is disassociated from the co-rotational relationship with the outer wheel 110 . At this time, if rotation of the hollow connecting shaft 130 relative to the hollow core shaft 140 exceeds a predetermined value (for example, 120 degrees), the first protruding portion 133 of the hollow connecting shaft 130 contacts the second protruding portion 146 of the hollow core shaft 140 , thereby stopping relative rotation between the hollow connecting shaft 130 and the hollow core shaft 140 so as to avoid stretching the elastic element 150 excessively and damaging the structure thereof, and to set the hollow connecting shaft 130 and the hollow core shaft 140 in a synchronous co-rotational relationship so that the hollow connecting shaft 130 and the hollow core shaft 140 rotate relative to the outer wheel 110 in the second relative rotation direction. [0104] In addition, if the external force driving the outer wheel 110 decreases, the operating principle of the pulley 10 of the present invention is substantially the same as the aforementioned operating principle in the case in which the outer wheel 110 stops rotating, and therefore it is not repeated herein. [0105] In the pulley 10 of the present invention, a belt (not shown in the figure) may be wound on the belt groove 112 of the outer wheel 110 so that the mechanical energy generating source can provide an external force to drive the belt, thereby driving the outer wheel 110 to rotate. In addition, the pulley 10 of the present invention is applicable to an alternator system, such as a power generation system and an alternator system of a vehicle. The pulley of the present invention is especially suitable to be used as a stator structure of an automotive alternator. When the pulley of the present invention is applied to an automotive alternator, the mechanical energy generating source is an automobile engine. [0106] In a preferred embodiment of the present invention, the tight-fit component 160 of the pulley 10 of the present invention may be omitted, and two ends of the elastic element 150 are fixedly connected to the stop wall 147 at the second end 142 of the hollow core shaft 140 and the stop wall 134 at the second end 132 of the hollow connecting shaft 130 . In this manner, when an external force drives the outer wheel 110 to rotate, the outer wheel 110 rotates relative to the hollow connecting shaft 130 in the first relative rotation direction and drives, through the clutch wheel 120 , the hollow connecting shaft 130 to rotate synchronously; the second end 132 of the hollow connecting shaft 130 presses the elastic element 150 , and while being pressed, the elastic element 150 pushes the stop wall 147 at the second end 142 of the hollow core shaft 140 , thereby driving the hollow core shaft 140 to rotate. At this time, if a rotation angle of the hollow connecting shaft 130 relative to the hollow core shaft 140 exceeds a predetermined value, the first protruding portion 133 of the hollow connecting shaft 130 contacts the second protruding portion 146 of the hollow core shaft 140 , thereby stopping relative rotation between the hollow connecting shaft 130 and the hollow core shaft 140 so as to prevent the elastic element 150 from being pressed excessively, setting the hollow connecting shaft 130 and the hollow core shaft 140 in a synchronous co-rotational relationship, and drive the rotor 30 to rotate. [0107] On the contrary, when the external force decreases or stops driving the outer wheel 110 to rotate, the hollow core shaft 140 continues to rotate due to inertia of the rotor 30 and stretches the elastic element 150 , and while being stretched, the elastic element 150 pulls the second end 132 of the hollow connecting shaft 130 , thereby driving the hollow connecting shaft 130 to rotate relative to the outer wheel 110 in the second relative rotation direction so that the hollow connecting shaft 130 is disassociated from the co-rotational relationship with the outer wheel 110 and idles in the clutch wheel 120 . At this time, if a rotation angle of the hollow connecting shaft 130 relative to the hollow core shaft 140 exceeds a predetermined value, the first protruding portion 133 of the hollow connecting shaft 130 contacts the second protruding portion 146 of the hollow core shaft 140 , thereby stopping relative rotation between the hollow connecting shaft 130 and the hollow core shaft 140 so as to prevent the elastic element 150 from being stretched excessively, and to set the hollow connecting shaft 130 and the hollow core shaft 140 in a synchronous co-rotational relationship, in which the hollow connecting shaft 130 and the hollow core shaft 140 idle in the outer wheel 110 . In addition, in a preferred embodiment of the present invention, in the pulley 10 of the present invention, the first protruding portion 133 and the second protruding portion 146 may not be disposed, the protruding ring 145 at the second end 142 of the hollow core shaft 140 is directly sleeved over the second end 132 of the hollow connecting shaft 130 , and two ends of the elastic element 150 are fixedly connected to the stop wall 147 at the second end 142 of the hollow core shaft 140 and the stop wall 134 at the second end 132 of the hollow connecting shaft 130 . Therefore, when an external force drives the outer wheel 110 to rotate, the outer wheel 110 rotates relative to the hollow connecting shaft 130 in the first relative rotation direction and drives, through the clutch wheel 120 , the hollow connecting shaft 130 to rotate synchronously, and the hollow connecting shaft 130 drives, through the tight-fit component 160 , the hollow core shaft 140 to rotate. At this time, if the friction provided by the tight-fit component 160 is insufficient to drive the hollow core shaft 140 to rotate, the stop wall 134 at the second end 132 of the hollow connecting shaft 130 presses the elastic element 150 , and while being pressed, the elastic element 150 pushes the stop wall 147 at the second end 142 of the hollow core shaft 140 , thereby driving the hollow core shaft 140 to rotate, so as to drive the rotor 30 of the alternator to rotate. [0108] On the contrary, when the external force decreases or stops driving the outer wheel 110 to rotate, the hollow core shaft 140 continues to rotate due to inertia of the rotor 30 and drives, through the tight-fit component 160 , the hollow connecting shaft 130 to rotate relative to the outer wheel 110 in the second relative rotation direction. At this time, if the friction provided by the tight-fit component 160 is insufficient to drive the hollow connecting shaft 130 to rotate, the hollow core shaft 140 stretches the elastic element 150 , and while being stretched, the elastic element 150 pulls the second end 132 of the hollow connecting shaft 130 , thereby driving the hollow connecting shaft 130 to rotate relative to the outer wheel 110 in the second relative rotation direction so that the hollow connecting shaft 130 is disassociated from the co-rotational relationship with the outer wheel 110 and idles in the clutch wheel 120 . [0109] Further, in a preferred embodiment of the present invention, in the pulley 10 of the present invention, the tight-fit component 160 , the first protruding portion 133 , and the second protruding portion 146 may not be disposed; the protruding ring 145 at the second end 142 of the hollow core shaft 140 is directly sleeved over the second end 132 of the hollow connecting shaft 130 , and two ends of the elastic element 150 are fixedly connected to the stop wall 147 at the second end 142 of the hollow core shaft 140 and the stop wall 134 at the second end 132 of the hollow connecting shaft 130 . In this manner, when an external force drives the outer wheel 110 to rotate, the outer wheel 110 rotates relative to the hollow connecting shaft 130 in the first relative rotation direction and drives, through the clutch wheel 120 , the hollow connecting shaft 130 to rotate synchronously; the stop wall 134 at the second end 132 of the hollow connecting shaft 130 presses the elastic element 150 , and while being pressed, the elastic element 150 pushes the stop wall 147 at the second end 142 of the hollow core shaft 140 , thereby driving the hollow core shaft 140 to rotate. [0110] On the contrary, when the external force decreases or stops driving the outer wheel 110 to rotate, the hollow core shaft 140 continues to rotate due to inertia of the rotor 30 and stretches the elastic element 150 , and while being stretched, the elastic element 150 pulls the second end 132 of the hollow connecting shaft 130 , thereby driving the hollow connecting shaft 130 to rotate relative to the outer wheel 110 in the second relative rotation direction so that the hollow connecting shaft 130 is disassociated from the co-rotational relationship with the outer wheel 110 and idles in the clutch wheel 120 . [0111] Although the present invention and advantages thereof are described in detail above, it should be understood that variations, alternative solutions, and modifications can be made herein without departing from the spirit and scope of the present invention which are defined in the appended patent application scope. Moreover, the scope of the present invention is not limited to the specific implementations of the process, machine, product, material composition, means, method, and steps described in the specification. For example, persons skilled in the art can easily learn from the disclosure of the present invention that existing or to-be-developed processes, machines, products, material compositions, means, methods and steps that substantially implement the same function or substantially achieve the same result as the corresponding implementation manner described herein may be used. Correspondingly, the appended patent application scope is intended to cover such processes, machines, products, material compositions, means, methods or steps.

The present invention relates to a pulley for an alternator, and in particular, to a pulley applicable to an automotive alternator. The pulley effectively mitigates the problem that a belt and a tension pulley of an alternator vibrate because a rotation speed of a vehicle engine changes, thereby improving the overall operating efficiency of the alternator and the service life of the working belt and the tension pulley.

CROSS REFERENCE TO RELATED APPLICATIONS [0001] The present application claims the priority of U.S. Provisional Application No. 60/704,839 filed Aug. 2, 2005 for a “Wearable Electronic Scorekeeping Device”. BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention is a wrist-wearable scorekeeping device, such as worn by a participant in racquet court games such as tennis, racquetball, and table tennis, and which includes a total of five settable buttons for navigating through mode/menus, displays and score entry functions. [0004] 2. Description of the Prior Art [0005] The prior art is well documented with examples of tennis and other portable type scorekeeping devices for assisting a player in keeping a correct score during game play. A first example from the prior art is set forth in U.S. Pat. No. 6,634,548, to Bowman, and which teaches a flexible strap removably attached to a casing, the casing in turn incorporating a circuit chip and a battery. The circuit chip is activated by one or more of four activation switches, these causing information (activities) to be displayed in one or more of four separate displays. Additionally, two additional activation switches are used to either turn the unit on/off and/or to reset one or more of the displays. [0006] Another example of a personal tennis score keeper is disclosed in U.S. Pat. No. 5,489,122, to Pittner, and which teaches a strip of sheet material having an upper surface and a lower surface, the upper surface bearing squares arranged in a linear array and forming three columns. A first column bears indicia indicating the number of games won by a player, another indicates the number of games won by an opposing player, and the remaining bearing indicia for indicating a score of each player during a game. A plurality of score markers are slidably secured to the strip in a juxtaposed slidable relation with respect to a column for marking a score. [0007] U.S. Pat. No. 3,777,699, issued to Pfleger, teaches a scoring device for tennis which accumulates and indicates the scoring for the game which is divided into and known as point score and game score. Scoring in tennis requires both an additive mode of operation for accumulating point score as well as game score, and a subtractive mode for point scoring under certain tie score conditions. The scoring device therefore comprises an input member and a totalize register for sequentially adding the point score until sufficient points have been accumulated to win the game. In advancing the point score register into the game winning indication the game totalizing register automatically advances to the next indication. The point score register is capable of the additive and the subtractive movements by selective movement of the input member. U.S. Pat. No. 4,331,098, issued to Rubano, teaches a tennis score keeper incorporating a small sized device for keeping score of a tennis match and which can be conveniently carried around on either a player's wrist or mounted on a racket. The device includes a frame on which is imprinted a row of point scores and a row of game scores along which arrows for each player are slidable. [0008] Finally, U.S. Pat. No. 6,210,296, issued to Gabriel, teaches a portable tennis scorekeeper device with a body attachable to an article of apparel or insertable within a pocket thereof worn by a tennis player and including a scoreboard applied to a side of the portable body. The scoreboard includes a middle region and a pair of opposite side regions. The middle region includes a first portion having a plurality of numbers and letters associated with points scored in a game of a tennis match. A pair of tracks extend along opposite sides of the first portion, second and third portions each being disposed on a side of one of the tracks opposite from the first portion and having a plurality of numbers associated with points scored in a tiebreaker of the tennis match. A pair of markers are each mounted to and for undergoing movement along one of the tracks and are alignable with the numbers and letters of the first, second and third portions. [0009] The side regions of the scorecard are each disposed on a side of one of the scorecard and third portions opposite from the tracks. Each side region includes a grid formed by a side axis, an end axis extending generally orthogonally to the side axis, a plurality of boxes arranged in rows and columns and aligned with one another adjacent to the side and end axes, a plurality of numbers associated with the games won in one or more sets of the tennis match being disposed numerically along the side axis and a plurality of numbers associated with sets of the match disposed numerically along the end axis. A plurality of markers are each mounted to and movable along the grid in generally orthogonal directions and positionable on one of the boxes of the grid and alignable with the numbers along each of the side and end axes of the grid. SUMMARY OF THE PRESENT INVENTION [0010] The present invention discloses an electronic wearable scorekeeping device which is an improvement over prior art designs in that it provides a five button arrangement for game play and display functions. The device is further adaptable to a number of different racquet type sports and, in one preferred tennis variant, includes features such as scorekeeping, identifying game and set tally, as well as unforced errors. [0011] A timekeeping mode is also employed and provides the ability to convert the wearable device between scorekeeping and watch functions. Additional features enable the present device to convert to scorekeeping in other related racquet sports, including badminton, racquetball, table tennis and the like. BRIEF DESCRIPTION OF THE DRAWINGS [0012] Reference will now be made to the attached drawings, when read in combination with the following detailed description, wherein like reference numerals refer to like parts throughout the several views, and in which: [0013] FIG. 1 is an illustration of an electronic scorekeeping device according to the present invention for use with tennis and in particular showing the arrangement of the five pushbutton arrangement for switching between play, time, display modes; [0014] FIG. 2 is a succeeding illustration of the electronic scorekeeping device and showing the display mode indicated; [0015] FIG. 3 is a tabular illustration of a series of variable names and associated purpose/functions for the scorekeeping device according to the present invention; [0016] FIG. 4 is a first flow schematic illustration of an initial play mode associated with the scorekeeping device of FIG. 1 ; [0017] FIG. 5 is a succeeding tally score flow illustration associated with the present invention; [0018] FIG. 6 is a flow schematic of a next game protocol; [0019] FIG. 7 illustrates a flow schematic of a next set game play protocol; [0020] FIG. 8 is a flow schematic of a normal score tally according to the present invention; [0021] FIG. 9 is a flow schematic of a protocol associated with a tiebreaker scoring situation; [0022] FIG. 10 is a flow schematic of a display score mode according to the present invention; [0023] FIG. 11 is a clear score schematic according to the present invention; [0024] FIG. 12 is a further succeeding display mode schematic; and [0025] FIG. 13 is a final schematic illustration of the electronic scorekeeping device according to the present invention and which provides a selectable mode for different racquet sports including racquetball, badminton, etc. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [0026] Referring now to FIG. 1 , a wrist-wearable electronic scorekeeping device is illustrated at 10 according to a preferred embodiment of the present invention. As indicated previously, the scorekeeping device is typically worn by a participant of a court-related sport, and the device 10 represents a first embodiment directed to the game of tennis, it being understood that the wearable electronic scorekeeping device is equally applicable to other racquet sports such as racquetball, badminton, table tennis and the like. [0027] In a preferred variant, the device 10 is worn upon a user's wrist (not shown). A strap or optional belt clip (also not shown) may also be provided for the wearability of the device, such as upon some secure location of the user, and such as again the belt or wrist. [0028] Referring again to FIG. 1 , the tennis scorekeeping device 10 includes a durable body exhibiting an LCD display face 12 and upon which are noted a series of indicia indications (such as in LCD format display) for indicating game play features associated with the present design. It is also understood that other means of illuminating display, such as including LED, phosphorescent or the like may also incorporated into the design. [0029] A series of pushbuttons are illustrated (in one non-limiting variant as illustrated) at various locations around a side periphery of the body and include first player score toggle (or A button) 14 (exhibited along one side of the device), and corresponding to second player toggle (or B button) 16 exhibited along an opposite side. Each of these toggle buttons are considered “universal” buttons and will allow the wearer to scroll through scores in one direction only to simplify. Each of these buttons further include a slip-resistant surface and enable the participant/player to toggle (up or through) to display a current score. [0030] A third display mode pushbutton is illustrated at 18 (see along lower right-hand side of the body), along with a fourth button 20 (lower left-hand side) is provided for viewing previously scored games and/or sets and matches. In play mode, fourth button 20 is provided for inputting unforced errors and clearing individual scores. Finally, a time mode button, see at 22 along right-hand side is provided for providing associated timer functions to the present design, such contemplated to include alternating between watch (i.e. timekeeping) and scoring functions through the pressing of a single button. [0031] As will be subsequently described, the two main modes for scorekeeping are play mode and display mode. In play mode, a player can indicate which team (or individual player) has earned a point, and such as by depressing either button 14 or 16 once. Additionally, the user can increase entry of unforced errors (see again button 20 ) and can further clear an individual score (hold down button 20 for one second) or can clear all scores (hold button 20 for three or more seconds). Pressing button 18 will take the player to the display mode. [0032] In the display mode, see illustration 24 in FIG. 2 , a user can navigate through current matches (whether or not completed), and to select fourth button to view individual games or sets. In this mode, first button 14 increments which game/set to display, whereas second button 16 decreases which game/set is being displayed. Third button 18 reverts to play mode (back to a previous game) and fifth button 22 to time mode, as previously described. In the illustration 24 of FIG. 2 , the device is illustrated in display mode according to the game of tennis (see indication 26 for “T”), game 2 (at 28 ) set 2 (at 30 ) and with a score of 30-50 (at 32 ), thus indicating a win by the “B” team with no unforced errors (at 34 for designation “UFE”). In contrast, the play mode of FIG. 1 is referenced, see on display face 12 at 36 , as indicated by tennis mode (again at 26 ), game 4 (at 28 ′), set 1 (at 30 ′), score (30-15), indicating a lead by team/player “A” and with one unforced error (at 34 ′). [0033] Referring now to FIG. 3 , a tabular illustration is shown at 38 of a series of variable names and associated purpose/functions for the scorekeeping device according to the present invention. The purpose of FIG. 3 is to illustrate, in tabular form, a sequential listing of variables utilized to maintain scores and flags of functions as will be described in more detail with reference to the following flowchart illustrations. [0034] FIG. 4 illustrates a first flow schematic illustration of an initial play mode 40 associated with the scorekeeping device of FIG. 1 . According to the flow sequence illustrated, a user presses button 1 (see again at 14 in FIGS. 1 and 2 ) and which commences by the user pressing either button (at 42 ) or button 2 (at 44 ) to determine the awarding of a point, to player A at 46 or to player B at 48 . [0035] Progressing to step 50 , a tally score indication queries whether either party/team has successfully achieved a score of 100. If no, game play continues along step 52 . If yes, and in the instance of an A score of 100 (as in step 56 ), a further instruct is made to increase a number of A games (at 58 ). If no, a further step 60 instructs to increase B game. At step 62 , a next game is selected and succeeding step 64 queries if the match is completed. If so, match score 66 is indicated at 66 and the protocol returns to display mode at 68 . [0036] If the query to pressing button 2 (at 16 ) is no (referencing back to step 44 ) succeeding step 70 queries whether to depress button 3 (see again also 18 in FIG. 1 ). If yes, display mode is illustrated at 72 . If no, a query whether to depress button 5 (at 22 ) is given at 74 . If yes, the display proceeds to time mode 76 and, if no, to querying whether to depress button 4 (at 20 ) at step 78 . [0037] If the answer to query 78 is yes, a further query asks whether to depress button 4 ( 20 ) for one section (at 80 and thereby to clear a given player/team score). If yes, a further query asks whether to hold button 4 for three plus seconds (at step 82 ). If no (at 84 ) all scores (A, B and UFE) are at 0 (at step 84 ) and, if yes, all scores are cleared at step 86 . If the answer to query 80 is no, step 88 instructs an increase of A error (again unforced error or UFE as referenced at 34 in FIG. 1 ) to eventual score display 90 . Finally, and if the answer to query 78 is no (at 92 ), the protocol returns to initial play mode 40 . [0038] Referring now to FIG. 5 is a succeeding tally score flow illustration associated with the present invention, and in particular its ability to adapt to multiple game type variants, is shown at 94 and includes a first query, at 96 , as to whether the game selection is tennis. If yes, at 98 , a tiebreaker query is made and, if yes, a tiebreaker score is indicated at 100 . If no, a normal tennis score is indicated at 102 . Irrespective of selection 100 or 102 , a display tennis score is referenced at 104 and the protocol ends at 106 . If the query to 96 is no, a further query is posited at 108 as to the selection of another type of game, e.g. racquetball, with a remaining tally protocol being repeated as to steps 98 - 106 . [0039] As is now shown in FIG. 6 , is a flow schematic of a next game protocol indicated at 110 queries, at step 112 , whether tennis is the selected game and, if yes, at step 114 instructs to record game statistics. At step 116 , A player score is queried (e.g. as shown as 100) and, if yes, at step 118 the scores are zeroed out. At succeeding step 120 , a number of A games (e.g. 7 ) is queried and, if yes, an increase of A sets is indicated at 122 ., succeeding which is the device issuing an audible sound (e.g. beep and which is understood to be incorporated into its hardware design) succeeding which a next set indication is shown at 126 and end step 128 . [0040] If the answer to query 120 is no, query 130 posits whether a given A and B game situation (e.g. Agame=6 AND Bgame<=4) exists. If yes, the protocol proceeds to step 122 previously described and, if no, a further query is posited whether both A and B games equal a given number (at 132 and shown as 6 games apiece). If yes, a tiebreaker indication is shown at 134 and, following a beep-beep audible alarm (see further at 136 ), the protocol proceeds to end step 138 . [0041] If the query to 116 is no, step 140 instructs both A and B scores to zero out, following which, at step 142 , a query is made as to whether B team/player is referenced to have played a certain number of games (e.g. such as 7 and corresponding to Agame=7 query in step 120 ). If yes, a number of team B sets (Bset) is increased at 144 . If no, query 146 reciprocates that shown at 130 and queries whether Bgame=6 AND Agame<=4). If yes, Bset is increased again at 144 and, if no, the protocol proceeds to step 132 previously described. [0042] FIG. 7 illustrates a flow schematic of a next set game play protocol, at 148 , and proceeds to a record set stats instruct at 150 . Succeeding steps include an instruct to zero out both A and B games to zero (at 152 ) and to subsequently query, at step 154 , if both an Aset or a Bset equals a specified number (e.g. 2). If yes, match completed indication is given at 156 and, if no (at 158 ), query 154 proceeds directly to beep indication 160 and end protocol step 162 . [0043] FIG. 8 is a flow schematic of a normal score 164 tally according to the present invention, such as again for tennis play, and queries at 166 if a point is to be awarded to player A. If yes, at 168 , an Ascore=0 is queried. If yes, an Ascore may be increased, such as to equal 15 (at 170 ). If no to 168 , a further query asks if Ascore is already at 15 (at 172 ). If yes, Ascore is queried at 30 (at 174 ) and, if no, Ascore is queried whether at 30 (at 176 ). If yes, at 178 , Ascore is advanced to 40 and, if no, a combined A and B score of 40 apiece is queried, at 180 , whether as being 40 apiece. If yes, Ascore is advanced to 50 (at 182 ) and, if no, queried further at 184 whether an Ascore=40 and a Bscore=50. If yes to 184 , Bscore is advanced to 40 and, if no, Ascore to 100 (at 188 ). [0044] The protocol of steps 168 - 188 is repeated in reciprocal as shown in FIG. 8 for query 190 as to whether Bscore=0 (this reciprocating previously described query 168 ). Succeeding query steps 192 - 210 are referenced in downwardly progressing fashion along the left side column of the flowchart of FIG. 8 and correspond with each of previously described steps 170 - 188 . The protocol of FIG. 8 concludes with end step 212 , progressing from either described step 188 or 210 . [0045] FIG. 9 is a flow schematic of a protocol associated with a tiebreaker scoring situation 214 and queries, at 216 , whether to increase Ascore (at 218 ). If no, at step 220 , a query is made whether to advance an Ascore, such as to >=7 AND Ascore-Bscore>=2). If yes, at 222 , Ascore is advanced to 100. [0046] Steps 224 , 226 and 228 correspond reciprocally to steps 218 , 220 and 222 , as to increasing Bscore, and if yes to either query 220 or 226 , either the A or B score is advanced to 100 and end step 230 referenced. If no to either 220 or 226 , the protocol proceeds directly to end step 230 . [0047] FIG. 10 is a display score flow schematic 232 and queries, at 234 , whether A and B score both equal 40. If yes, at step 236 , “deuce” indication is made and, if no, a query is made at 238 whether Ascore=40 and Bscore=50. If yes “Adou” indication is made at 240 and, if no, further query 242 asks is Ascore=50 and Bscore=40. If yes, at 244 “Adin” is indicated and, if no, Ascore=100 is further queried at 246 . If yes, at 248 , “Awin” (A team wins) is indicated at 248 and, if no, Bscore=100 is queried at 250 . If yes, Bwin (B team wins) is indicated at 252 . [0048] If no to query 250 (or if yes to any preceding indications 236 , 240 , 244 , 248 and 252 ), further Ascore:Bscore (e.g. the present team scores where either team has some point total under 100, or any other preset total point amount constituting a win) is referenced at 254 . Following that, an unforced errors (UFE) indication is given at 256 and proceeds to end protocol step 258 . [0049] FIG. 11 is a clear score schematic according to the present invention and references, at 260 , an all scores cleared indication. At 262 , a further query is made if the protocol application is for tennis and, if yes, a succeeding series of indications are provided, at 264 , as to A/B score, game, set, error and match start particulars. At 266 , a clear game stat array command is given and, at 268 the protocol ends. If the query to 262 is no, a further query ( 270 ) requests if the application is for another type of game, e.g. racquetball, and then proceeds to repeat the protocol steps associated with that game and as previously described at 262 - 268 . [0050] FIG. 12 is a further succeeding display mode schematic at 272 (see also again FIG. 2 ) and progresses to mode=display commend 274 and, subsequently, to game=declared query 276 . If no, game=1 set=1 indication is made at 278 and, if yes, query 280 posits whether button 3 (at 18 ) is depressed. If yes, select mode is referenced at 282 and, if no, query 284 asks as to whether button 1 is depressed. If yes, which=game indication is made at 286 and proceeds, if yes, to increasing a game or maximum game number at 288 . If the query to 286 is no, query 287 asks the set number being played (Which=set) and if yes, command 289 increments a set maximum whereas, and if no, protocol command advances to query 290 (also achieved by answering no to query 284 ) which posits whether button 2 is to be depressed. If yes, which=game query is referenced at 292 and, if yes, view=set indication is provided at 294 . If no to query 292 , which=set query is posited at 298 and, if yes, view=match indication is made at 296 and, if no, view=game indication at 300 . [0051] Either of steps 296 and 300 , as well as a negative answer to query 290 , progress to a query at to pressing button 4 , at 302 . If yes, which=game query is made at 304 and, if yes again, which=set indication is made at 306 . If no to 304 , which=set query is posited at 308 and, if yes to that, which=match indication is made at 310 and, if no to 308 , which=game indication at 312 . If no to query 302 , further query 314 asks if button 5 is to be depressed. If yes, “to: time mode” indication is provided at 316 and, if no, view=game query is asked at 318 . If yes, “game# information” is provided at 320 . If no to 318 , view=set query is provided at 322 . Finally, a yes answer to query 322 progresses to a “set# info” indication at 324 or, if no to 322 , to a “match info” indication 326 , from any of 320 , 324 , or 326 commands, the display mode 272 repeats. [0052] FIG. 13 is a final schematic illustration of the electronic scorekeeping device, at 328 , according to the present invention and which provides a selectable mode for different racquet sports including racquetball, badminton, and the like. In particular, mode=select indication is made at 330 and progresses to select command 332 . A further query, at 334 , asks whether type=declared and, if no, can reference type=tennis at 336 or, alternatively and if yes to 334 , query 338 asks if button 3 is to be pressed. If yes, the protocol proceeds to play mode 340 and, if no, query 342 asks (posits) if button 4 is to be pressed. If yes again, a type of game play selection is made and may include selected tennis ( 344 ), racquetball 346 or badminton 348 . [0053] If yes to any of 344 , 346 , or 348 , a further selected one of “type=racquet” ( 350 ), “type=badmit” ( 352 ) or “type=tennis” ( 354 ) commands is given. If no to all, “type=tennis” ( 356 ) is selected as the default and proceeds to query 358 as to whether button 2 is to be pressed. If yes to that query, display 360 indicates a potential selection of a given level of game play, e.g., recreational, competition, tournament, etc., and, if no to 358 , further query 362 asks if button 5 is to be pressed. If yes to 362 , “time mode” indication is made at 364 and, if no, at 366 the protocol returns to display mode 328 . [0054] The electronic scorekeeping device, according to any preferred variant, includes a power supply in the form of a watch battery and which is similar to that used with other conventional types of electronics, cameras, watches, etc. In a preferred application, the device 10 is universally applicable to all court-related sports and, potentially, other recreational sports. Additional features include built-in illumination, in the event of operating the watch in semi-darkness or other limited light conditions (see again lighted display face 12 and 32 in FIGS. 1 and 2 , respectively), a scratch-resistant display surface (e.g. sapphire crystal), audible signaling (e.g. a beep or chime sound to indicate match/set), as well as colorful designs and stylish arrangements to enhance the attractiveness of the device. [0055] It is also envisioned that a single electronic wearable device can be programmed to operate according to all of the game play variants. Such a device can also be adapted to include other participant related games, beyond those described, and by which it is desirable to incorporate an electronic type device with processor capabilities for inputting scoring and other relevant parameters associated with game play (volleyball, handball, wallyball, etc.). [0056] The previously described scoring protocol illustrations are relevant to the various embodiments of the present invention and which establish the manner in which the electronic device is manipulated according to a given game play variant. The protocol information is submitted as being exemplary only of one manner in which the electronic scorekeeping device is utilized and is not interpreted as limiting as to the manner in which the device may be configured or operated. It is also envisioned that the wearable scorekeeping device can be adapted to operate with other, non-racquet related sports including such as volleyball, or any other player/team participant sport related game or event. [0057] Having described my invention, other and additional preferred embodiments will become apparent to those skilled in the art to which it pertains, and without deviating from the scope of the appended claims.

An electronic wearable scorekeeping device for use with a racquet/court-related sport. The device includes a body capable of being attached to a sport participant, such as by a wristband, strap or, suspending lanyard worn by the user. The body includes a display face and a maximum of five individually depressible buttons, these related to at least one of a selected game type, player score, play/display mode, advantage/UFE, and time mode.

RIGHTS OF THE GOVERNMENT The invention described herein may be manufactured, used and licensed by or for the United States Government for governmental purposes without the payment to me of any royalties thereon. BACKGROUND OF THE INVENTION The invention relates in general to the measurement of fluid pressure and, in particular, to a method and apparatus for converting an absolute fluid pressure to a differential fluid pressure. In many fluidic circuits, it is necessary to convert the absolute pressure of a pressurized fluid to a differential pressure indicating the pressure of the pressurized fluid relative to a predetermined reference pressure. For example, in a pressure regulating circuit, a single pressure output signal from a rectifier may be used as a control signal to a differential circuit. If the desired reference pressure is available, the unknown pressure can be compared with the reference pressure in a differential amplifier. However, in many applications, the desired reference signal is not available. In such a case, a passive circuit consisting of a parallel arrangement of an orifice and a capillary can be used to convert the unknown pressure into two flows which can be used as control pressure signals indicating the difference between the unknown pressure and a predetermined reference pressure. When the unknown pressure is correct, the flows are equal and no differential pressure occurs. When the pressure is low, more flow goes through the orifice giving rise to a differential signal in one direction. When the pressure is high, the flow is higher through the capillary giving rise to a differential signal in an opposite direction. Generally, pressure sensors for sensing an unknown fluid pressure inherently have a high input impedance. In this known arrangement, due to this high input impedance, the orifice will always contain a high content of linear or capillary features giving rise to a low sensitivity. SUMMARY OF THE INVENTION It is a primary object of the invention to provide a fluidic absolute-to-differential pressure converter which has a high sensitivity without requiring a reference pressure or a separate power supply. It is another object of the invention to provide a method for converting a single fluid pressure to a differential fluid pressure which does not require a reference pressure source. The method and apparatus according to the invention utilizes asymmetrical characteristics of laminar proportional amplifiers (LPA). By choosing an LPA designed in such a way as to have a severe mechanical offset, the differential pressure out at low pressures will favor one output over another. By then choosing a nozzle exit configuration and a control edge spacing which cause jet deflection to the opposite side when the gain of the LPA increases with supply pressure, then at high supply pressures, the jet will deflect and favor the other output. By adjusting the control resistance, the set point, i.e., zero differential between the two fluid outputs, can be controlled. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood, and further objects, features, and advantages thereof will become more apparent, from the following description of preferred embodiments, taken in conjunction with the accompanying drawings in which: FIG. 1 is a plan view of a first embodiment of the invention; FIG. 2 is a plan view of a second embodiment of the invention; FIG. 3 is a plot of the LPA differential output signal versus the LPA input pressure signal; FIG. 4 is a family of curves of LPA input versus output pressure signals for respective LPA control resistances; and FIG. 5 is an electrical schematic diagram of a frequency control circuit which includes the absolute-to-differential pressure converter described herein. DESCRIPTION OF PREFERRED EMBODIMENTS The absolute-to-differential pressure converter 10 shown in FIG. 1 includes a supply input 12 which is disposed at one end of the converter 10 and is connected to receive a fluid whose absolute pressure is to be converted to a differential pressure indicating the pressure of the fluid relative to a desired reference pressure. Two fluid outlets 14, 16, separated by a splitter 18, are disposed at an opposite end of the converter 10. A supply nozzle 20 is connected in fluid communication with the supply input 12 to direct a fluid supply stream 22 from the supply input 12 into the converter 10 along a centerline 24 of the supply nozzle 22. The supply nozzle centerline 24 is offset in a lateral direction from the upstream end 26 of the splitter 18 by a distance 28 such that at least most of the supply stream 22 is directed by the supply nozzle 20 towards the output 14. For example, when the two outputs 14, 16 are disposed symmetrically on opposite sides of an axis 30 of the splitter, the splitter axis 30 can either be disposed in spaced parallel arrangement with the supply nozzle axis 24, as shown in FIG. 1, or can be disposed to intersect the supply nozzle axis 24 upstream of the splitter 18, as shown in FIG. 2, to achieve the desired lateral offset 28 of the supply nozzle centerline 24 at the splitter end 26. Two control ports 32, 34 are connected to an available control fluid source through respective adjustable fluid resistors 36, 38, which may be either linear or nonlinear. For example, when the supply stream is formed of pressurized air, the ambient air surrounding the converter 10 can be used as the control fluid source for the control ports 32 and 34. When the fluid used to form the supply stream 22 is a liquid, the control fluid source for the control ports 32, 34 can be a low pressure return line of the fluid system. The control ports 32 and 34 include respective control nozzles 40, 42, which are disposed on opposite sides of the supply stream 22 to establish fluid communication between the control ports 32, 34 and an interaction zone 44 which extends between the control nozzle 20 and the edges 46, 48 of two control nozzle vanes 50, 52, respectively. The two control nozzle vanes 50, 52 are disposed asymmetrically relative to the supply nozzle axis 24, wherein the vane edge 48 is disposed closer than the vane edge 46 to the axis 24. Since these vane edges 46, 48 determine not only the length but also the lateral extent of the interaction zone 44, this interaction zone 44 is also asymmetrically offset from the supply nozzle centerline 24. The converter 10 also includes two sets of vents 54 and 56, 58 and 60, which are disposed on opposite sides of the supply stream path intermediate the interaction zone 44 and the outlets 14, 16, and which are open to ambient pressure to provide dumping points for fluid inside the converter 10. Operation When the fluid stream 22 is flowing through the converter 10, fluid from the available control fluid source will be drawn through two flow resistors 36, 38, through the two control ports 32, 34, and about the two control nozzle edges 46, 48, respectively, to become entrained with the supply stream 22. Assuming the two flow resistors 36, 38 are adjusted to the same value, more control fluid will be drawn into the supply stream 22 from the control port 34 than from the control port 32 because the control nozzle edge 48 associated with the control port 34 is disposed much closer to the edge of the supply stream 22 than is the control nozzle edge 46 associated with the control port 32. Consequently, the fluid pressure drop through the flow resistor 38 and the control port 34 will be greater than the pressure drop through the flow resistor 36 and the control port 32, and the pressure of the control fluid at the control nozzle 42 will be less than the pressure of the control fluid at the control nozzle 40. Because of this difference in the pressures exerted on opposite sides of the supply stream 22 in the interaction zone 44, the supply stream 22 will be diverted in the direction of the output 16. Thus, the mechanical offset of the control nozzle vanes 50, 52 in one lateral direction from the supply nozzle axis 24 produces an opposite effect on the differential pressure output signal between the two outputs 14, 16 from that of the mechanical offset of the splitter 18 in an opposite lateral direction from the supply nozzle axis 24. FIGS. 3 and 4 show various curves of the supply pressure P s at the converter supply input 12 versus the differential pressure ΔP produced between the two converter outputs 14 and 16. In order to indicate whether the pressure at one output 14 is greater or less than the pressure at the other output 16, the differential pressure ΔP has arbitrarily been designated as a positive value when the pressure at the output 14 is greater than the pressure at the output 16, and as a negative value whenever the pressure at the output 14 is less than the pressure at the output 16. Curve 62, shown as a dashed line in FIG. 3, is a plot of the supply pressure P s versus the differential pressure ΔP which would be produced between the two outputs 14, 16 of the converter 10 solely as a result of the mechanical offset of the splitter 18 described above. Curve 62 shows that this mechanical offset of the splitter causes the output differential pressure ΔP to monotonically increase in the positive direction with an increase in the supply pressure P s . The rate of change of the output differential pressure ΔP increases due to a reduction of viscous losses as the supply pressure P s increases. Curve 64, shown as a dotted line in FIG. 3, is a plot of the supply pressure P s versus the output differential pressure ΔP which would be produced solely as a result of the mechanical offset of the control nozzle vanes 50, 52, described above. As shown by curve 64, the mechanical offset of the control nozzle vanes 50, 52 results in a nonlinear change in the output differential pressure ΔP as a function of increasing supply pressure P s . Essentially no change in the output differential pressure ΔP is produced at low supply pressures since there is no LPA gain. Thereafter, when the gain becomes appreciable, the output differential pressure ΔP rapidly increases in the negative direction. Curve 66, shown as a solid line in FIG. 3, shows a plot of the supply pressure P s versus the output differential pressure ΔP produced as a result of the control nozzle vanes 50, 52 and the flow splitter 18 being oppositely offset from the supply nozzle centerline 24. Curve 66 clearly shows that these two mechanical offsets produce opposite effects on the output differential pressure ΔP. At low supply pressures P s , the effect of the mechanical offset of the flow splitter 18 predominates, and the output differential pressure ΔP increases the positive direction with increasing supply of pressure P s . Thereafter, as the supply P s continues to increase, the effect of the mechanical offset of the control nozzle vanes 50, 52 predominate, and the output differential pressure ΔP increases in the opposite negative direction. The geometry of the converter 10 can be set so that the output differential pressure ΔP is zero at the desired reference pressure P r . The slope of the curve 66 corresponds to the converter sensitivity. Typically, the value of (ΔP)/ΔP s is in the range of about 0.1 to 2.0 at the reference pressure P r . The supply pressure P s at which the output differential pressure ΔP crosses zero, corresponding to the desired referenced pressure, can be varied by varying the resistance value of either flow resistor 36 or 38. If the resistance of the flow resistor 38 is increased, the jet edge pressure adjacent to vane edge 48 will be reduced by restriction of the entrained flow of control fluid, and the jet deflection will be augmented. Similarly, an increase in the resistance value of the flow resistor 36 will cause less jet deflection. By varying the ratio of the two flow resistors 36 and 38, the zero crossing or set point P r of the output differential pressure can be adjusted, as seen in FIG. 4. The curve shown by a solid line in FIG. 4 is a plot of the supply pressure P s versus the differential pressure ΔP where the resistance R 38 of the flow resistor 38 is equal to the resistance R 36 of the flow resistor 36. This curve can be changed to that shown by a dashed line in FIG. 4 to thus raise the set point P r to P r ' by either increasing the resistance R 36 of the flow resistor 36 or decreasing the resistance R 36 of the flow resistor 38 so that R 38 <R 36 . Similarly, the curve can be changed to that shown by a dotted line in FIG. 4 to lower the set point P r to P r " by either increasing the resistance R 38 of the flow resistor 38 or decreasing the resistance R 36 of the flow resistor 36 so that R 38 >R 36 . An example of a fluidic absolute-to-differential pressure converter 10, such as shown in FIG. 1, is seen below. In this example, the pressurized fluid is pressurized air and the control fluid is air at atmospheric pressure. The converter 10 has a supply flow rate of 0.3 liters per minute through the converter at 4 mm of Hg supply pressure through a supply nozzle 20 with a cross-section of 0.02×0.02 inches. The fluid outputs 14 and 16 are 0.027 inches wide by 0.020 inches deep. The flow splitter 18 has a rounded upstream end 26 of approximately 0.005 inch radius which is spaced from the supply nozzle 20 by a distance of approximately 0.180 inch. The flow centerline 30 of the splitter 18 is offset 0.005 inch from the supply nozzle centerline 24 in one lateral direction, and the centerline of the control nozzle vanes 50, 52 are offset 0.001 inch from the supply nozzle centerline 24 in an opposite lateral direction, as shown in FIG. 1. The edge 46 of the control nozzle vane 50 is spaced approximately 0.0135 inch from the centerline 24, and the control nozzle vane 52 is spaced approximately 0.0115 inch from the centerline 24. The two control nozzle vanes 50, 52 are disposed downstream from the supply nozzle 20 by a distance of approximately 0.02 inch along the centerline 24. When the atmospheric vents or flow resistors 36, 38 have equal flow resistances, an absolute-to-differential pressure converter of this design produces a differential pressure between the two outputs 14, 16 of the value of zero at the stated supply pressure of 4 mm of Hg. A typical application of the invention described herein can be seen in FIG. 5. FIG. 5 discloses a fluidic automatic frequency control circuit 70 where the frequency impulses from a fluid oscillator frequency generator 72 are converted to the output pressure of the fluid frequency-to-analog convertor 74. The output pressure of the f/A converter 74 is converted to a differential pressure in the fluid outputs of an absolute-to-differential pressure converter 10, as described above. This differential signal is then fed to a high gain amplifier controller 76, which utilizes this signal to provide a feedback signal 78 in the form of an adjusted supply pressure to the frequency generator 72. The differential signals from the fluid absolute-to-differential converter 10 can also be used as control inputs in an array of fluid amplifiers downstream from the absolute-to-differential converter to form a pressure regulator with no moving parts. One advantage of the absolute-to-differential pressure converter described herein is that it has the low output impedance of an LPA and readily matches into other LPA circuitry. Also, a high input impedance is possible by the choice of a supply nozzle size that does not affect sensitivity. Further, this converter requires neither a separate power supply nor a pressure reference. It has the advantage over mechanical devices such as pressure regulators in that it includes no moving parts, and is thus highly reliable, and there is no mechanical friction forces to overcome, thus giving response to any pressure changes. Since many modifications, variations, and additions to the invention are possible within the spirit of the invention in addition to the specific embodiments described herein, it is intended that the scope of the invention be limited only by the appended claims.

A method and apparatus for converting the absolute pressure of a pressuri fluid to a differential pressure indicating the fluid pressure relative to a reference pressure. The pressurized fluid is directed asymmetrically into a laminar proportional amplifier (LPA) along a centerline toward a first of two outlets at a velocity determined by the fluid pressure. The LPA includes first and second control inlets disposed on opposite sides of the directed fluid jet and connected to a common source of control fluid, the first control inlet being disposed on the same side as the first outlet, and the second control inlet being disposed on the same side as the second outlet. The first and second control inlets include respective first and second downstream control edges which are asymmetrically disposed on opposite sides of the jet, with the second control edge being disposed closer than the first control edge to the centerline; consequently, the jet is deflected towards the second outlet in accordance with the jet velocity such that the differential pressure generated by the jet between the first and second outlets is zero when the fluid pressure is equal to the reference pressure.

RELATED PATENTS This application is a divisional of U.S. patent application Ser. No. 07/952,071 filed on Sep. 25, 1992. FIELD OF THE INVENTION The invention relates to mail processing and delivery systems and more particularly to cancelling apparatus which is adapted to mark or "cancel" the postage affixed to or printed on a mailpiece to prevent its reuse. BACKGROUND OF THE INVENTION In typical mail distribution operations at the various post offices worldwide, the metered and stamped mail is received in enormous volumes. In large mail distribution centers, if the mailpieces carry an imprinted indicia, the mailpieces are processed by sorters to sort the mail to its destination or in the event that the mailpiece has an affixed stamp, it is processed by the so-called facer-canceller which can orient the mailpiece cancel the stamp prior to the sorting of these mailpieces. In either case the actual weight of the mailpiece is normally never checked during the course of these operations. As is well known in the United States and in many other countries, the postage amount required for delivery increases with the weight and size of the mailpiece. Accordingly, the Post Office will lose revenue on its delivery if in fact the postal rate (according to the postal Weight-Rate Tables) corresponding to the weight and/or size of the mailpiece exceeds the postage paid. In fact, one of the major factors contributing to loss of revenue is perceived to be the underpayment for individual mailpieces, and particularly those individual mailpieces being sent in batch mailings. In the conventional postal delivery systems, however, the costs associated with verifying the correct postage on an individual mailpiece may be prohibitive in terms of employee time since each piece to be verified must be manually extracted and individually weighed and rated either at entry into the mailstream or at some time during subsequent mail processing and delivery. For batch mailings, there is normally a manual sampling and rating of mailpieces prior to merging them into the mailstream at the facility, but it will be appreciated that this sampling is at best inefficient because of possible human errors and the small sample size of such manual checking. U.S. Pat. No. 5,072,400 to Mandulay discloses a system for monitoring the integrity of mail pieces passing through the delivery system for tracking and prevention of theft. In this system a data base is updated to include the initial weight and destination address of a mailpiece. As the mailpiece moves through the system the weight and the destination data are compared at the various stages to determine any discrepancies. U.S. Pat. No. 5,019,991 to Sansone et.al., entitled CERTIFIED WEIGHER-SHORT PAID MAIL describes a system for assuring the post office that the weight of a mailpiece which would ordinarily require more postage was correctly accounted with consideration to other postage discounts, for 25 example, number of mailpieces being sent to a particular ZIP-code. U.S. Pat. No. 5,008,827 to Sansone, et.al., entitled CENTRAL POSTAGE DATA COMMUNICATION NETWORK describes a user system for certifying by marking a pre-posted mailpiece that any required additional postage due on the mailpiece has been accounted for to the post office. While each of these work well for the intended purposes, they do not address the problem of routinely assuring that mailpieces which may enter the mailstream at the post offices from the counter, letter boxes or in batch mailings carry sufficient postage. The teaching of the '400 patent also requires the use of extensive computer facilities for maintaining the database and for certifying and protecting the accounting for postage. SUMMARY OF THE INVENTION It is therefore an object of the invention to provide a novel method and apparatus for verifying that the required postage amount is affixed to a mailpiece. It is a further object to provide a method and apparatus for automatic verification of batches of mailpieces. These and other objects of the invention are realized in an apparatus for verifying postage paid comprising a facet means operative for orienting and presenting mailpieces for cancelling of postage affixed thereto; a weighing module for receiving a mailpiece having postage affixed thereon from the facet means and weighing said mailpiece; printing means; a transport means for transporting the mailpiece from the weighing module to the printing means; said printing means being operative for marking on said mailpiece a cancelling marking corresponding to correct postage for the mailpiece in correspondence with a determined rating and a weight as determined by the weighing means, whereby the marking enables comparison between postage affixed to the mailpiece and the actual value of required postage for delivery of the mailpiece. In a second embodiment the apparatus comprises a data entry means and a display for input and output of data relating to a batch of mail; a weighing module for weighing a mailpiece having postage affixed thereon; scanning means for reading character information from the mailpiece; printing means; a transport means for transporting the mailpiece for scanning thereof from the weighing module to the printing means; said printing means being selectably operable for marking on said mailpiece a marking corresponding to correct postage for the mailpiece in correspondence with a weight as determined by the weighing means and rating information determinable from scanning of said mailpiece, whereby the marking enables comparison between postage affixed to the mailpiece and the actual value of required postage for delivery of the mailpiece. In another aspect there is provided a method for verifying the postage on a mailpiece having postage affixed thereto comprising the steps of weighing a mailpiece having postage previously affixed thereto, setting a printing mechanism adapted for printing postal value to a value corresponding to a weight obtained from the weighing of said mailpiece, and cancelling the previously affixed postage using said printing mechanism to provide a cancellation mark that includes a value of postage calculated from rating information and the weight obtained from the weighing step. In any of the foregoing aspects of the invention, the printing means may further comprise means operative for printing the date of cancellation. BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a block diagram of a cancelling apparatus in accordance with the invention. FIG. 2 is a flow chart of the basic operation of the cancelling process in accordance with the invention. FIG. 3 is a block diagram of another embodiment of an apparatus particularly adapted for verifying larger batches of mail. FIG. 4 is a flow chart of the method for verifying postage in accordance with the invention in respect of the apparatus of FIG. 3. DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1, there is shown generally at 10 a block diagram of a postage verifying system in accordance with the invention. The apparatus comprises a racer 12 which may be a conventional racer portion of a conventional facer-canceller, such as those typically used in the present mail-distribution facilities of the Post Office. The facer 12 receives a mailpiece indicated at 14 from the input hopper 16 which holds the mailpieces to be verified and orients the mailpiece in conventional manner to position the mailpiece in the proper position for cancelling of the postage stamp (or meter impression). The term postage affixed to a mailpiece as used herein shall refer to both stamps and meter impressions signifying that value has been paid for the sending of the mailpiece. In accordance with the invention, instead of being transported as previously known to the conventional canceller section of the facer-canceller, the oriented mailpiece 14 is delivered by a mailpiece transport such as the continuous belt indicated at 18 to the input hopper 20 of a mailing machine comprising feeder section 22 which includes a transport 24 and an electronic postage meter section at 26. Mailpieces such as the mailpiece 14 placed on the hopper 20 are serially fed to the meter section 26 for overprinting of a cancelling indicia by a printing mechanism shown in block 28. The cancelling indicia printed by printing mechanism 28 includes postage value and, if desired or required by Post Office regulations for example, the current date. The mailing machine feeder section 22 includes scale 30 for weighing the mailpiece and communicating its weight to a microprocessor control apparatus 32 so that the appropriate postage value may be imprinted on the mailpiece as communicated either directly to the meter or by way of the microprocessor control apparatus 32. In the preferred embodiment illustrated here, the meter section 26 comprises a detachable meter which may be easily removed and replaced by similar types of meter apparatus having other features as described below. If desired, a suitable keyboard 34 and display 36 communicate with the microprocessor control apparatus 32 for input and output of information in relation to scale 30, meter section 26, and transport 24. A more detailed description of a suitable mailing machine is described in U.S. Pat. No. 4,935,078 entitled High Throughput Mailing Machine Timing, assigned to the assignee of the instant application and specifically incorporated by reference herein. It will be appreciated by those skilled in the art that in order to provide the cancelling function in accordance with the invention, the inking of the indicia normally associated with postage metering function must be changed to be indelible ink, for example the conventional ink used by a Postal Authority, in order to prevent the washing of stamps for reuse. Other colors may also be used, if desired for instance, to distinguish the mailpieces that have been cancelled by the apparatus in accordance with the invention from the conventional cancellations of the Postal Authority. It will also be understood that the printer which in a preferred embodiment is a postage meter printer, is not required in the instant situation to account for funds expended and therefore the accounting routines and security measures normally associated with the known meters may be simplified. While it is not believed necessary to change the format of the indicia typically used for imprinted postage meter indicias, except as necessary to distinguish it from valid postage meter impressions, it will also be appreciated that other markings are also contemplated in the event that a particular figure is required to allow the underlying value on the previously affixed postage to be readable. In operation of the apparatus of FIG. 1 as seen in conjunction with the flowchart as illustrated in FIG. 2, the mailpieces having previously affixed postage are placed in the hopper 16 of the facet portion where the individual mailpieces are oriented and fed to hopper 20 of the mailing machine feeder section 22. The mailpiece is weighed, block 60 of FIG. 2, and the printer is set for the current date and appropriate postage, block 70, in accordance with the weight of the mailpiece and pertinent rating information as stored in the microprocessor control 32 or input through keyboard 34 or other input means. As the mailpiece is transported through the meter portion, an indicia including the date and valid postage amount for the particular mailpiece is printed over the previously affixed postage amount, block 80, thereby allowing easy comparison by a postal route carrier or other Post Office official to determine whether additional postage is due while at the same time cancelling the previously affixed postage. It will be appreciated that the mark showing the amount of postage required may be placed anywhere on the mailpiece so long as the cancelling of the previously affixed postage is also accomplished. FIG. 3 shows another embodiment of the invention 5 particularly adapted for verification of larger batches of mail wherein the electronic meter section shown at 26' further comprises a scanner 38, such as, for example, one of the well known OCR readers and/or postal bar code readers, which is operative to read address as well as other determined information and the value of the postage affixed to the mailpiece as well as any presort and barcode information if desired, in order to capture additional information such as the address and the affixed postal amount. It will be understood that the scanner can be placed at other positions along the path of the mailpiece, however when located in the meter section in cooperation with the printer, the replacement of the meter unit with the scanner printer is enabled in a particularly convenient manner. In a preferred embodiment, the printing mechanism may be made to operate selectably where it is desired to simply store the information in relation to the scanned mailpieces and compare the actual total postage due with the amount submitted by the sender, for example, on a manifest. This result may then be printed at the end of the run either by the printing mechanism 28 or by a separate printer (not shown) for comparison to a manifest or other documentation. It should be noted that in FIG. 3 those modules which are unchanged from FIG. 1 retain the same numbers. Additional mailpiece measurement apparatus indicated at block 40 may also be included to determine the sizes of the pieces in order to further determine if a particular rating should be applied. This may be a separate module, but it could also be conventional photodiode detectors, arranged as required in the transport path at a convenient point, which are blocked and unblocked by various sized mailpieces If required, additional memories shown at 42 for storage of information and look-up tables may be added in known manner to communicate with the microprocessor control 32. Similarly, the required input data and output data from the mailing machine control 32 may be obtained from and/or fed to additional computers or data storage devices not shown. The mailpieces may be sent to an optional sorter 44 for further processing if desired. FIG. 4 illustrates the method for verification using the apparatus of FIG. 3. The first step indicated at 100 is sampling of the batch of mail submitted for verification. It will be understood that the sample may include the entire batch of mailpieces in a particular mailing, but this is believed to be inefficient and not necessarily required for adequate verification of a batch of mail. Two attributes of the sampling have been found to be important. The first is to assure that the sample is random, in other words, that the selected pieces are not biased in terms of belonging to a group not with a specific property not present in other members of the batch. It will be understood that randomness can never be guaranteed; however, it is believed that standard measures such as selecting mailpieces from different sources and places, having different size, weight and make-up can establish reasonable randomness of the sample. The second important attribute is the size of the sample taken. The size of the sample in a sense guarantees representativeness of the sample. It will be appreciated that the size of the sample can be determined using well-known statistical procedures. See, for example, Snedecor and Cochran, Statistical Methods, The Iowa State University Press, 1979. The size of the sample is a function of the allowable error, the desired confidence level and the estimated size of the batch. It has been found, by way of example only and not as a limitation, that even for a very large mailing, a 1% error having a 95% confidence level defines the size of sample as 1,475 mailpieces assuming a binomial distribution for correct/incorrect postage and probability of success (correct postage) at 96% and probability of incorrect postage 4%. With a mailing machine capability of processing, for example, only 3000 pieces per hour, a sample of this size may be processed in about 30 minutes. For best results, the determination can be carried out under control of the microprocessor control 32 and the sample size displayed as a result of operator input as to size of the batch, allowed error and confidence level. After entry of the data by the operator the required sample size is displayed. Once the sample size is determined the mailpieces are selected and processed. As the individual mailpieces are fed through the mailing machine, the geometrical dimensions are obtained, block 110; the weight is obtained, block 120; the level of standardization, that is, the depth and format of the postal code present on the mailpiece is determined, block 130; the level of service, for example, desired delivery time is obtained, block 140; the group property or presort level is obtained, block 150; the declared or printed postage value is read, block 160; and the class and other special services are obtained, block 170. The proper postage rate for a given mailpiece is then computed using the data elements thus obtained, block 180. It will be appreciated that this computation can either be by way of algorithm or simply by using a look-up table which has multiple discrete entries for size, weight, level of service, etc. It will be understood that where the postage rate is also determined by the level of presort, this group property is not determinable from a single mailpiece. In this case it will be appreciated that the entire group of mailpieces which belong to the same sorting entity must be included in the sample and in this case the assurance of sample randomness is more difficult. If the individual mailpieces are collected from street boxes, for example, at the YES branch of decision block 190, the sorter 44 may be set to outsort or otherwise flag mailpieces for which the determined postage rating value fails to match the amount affixed to the mailpiece, block 200. The incorrectly postaged mailpieces can be returned to sender for insufficient postage. In the alternative, particularly where the mailpieces have no printed evidence of postage to compare, at the NO branch of block 190, the postage due for the mailpiece is added to a running total, block 210, and the routine loops back to repeat the checking of the next mailpiece. When the last mailpiece is checked, decision block 220, the postage due for the entire mailing is computed based on the verified sample and printed out along with the allowed margin for error, block 230. This total can be compared with the manifested value of the mailing and additional postage can be levied in the event the discrepancy exceeds some specified value. It will be appreciated that if desired the value determined for each mailpiece could be printed on the mailpiece to provide proof of checking in this situation as well. It will be understood that the embodiment illustrated in FIG. 3 can also be simplified to operate in a semiautomatic mode. Such a system may, for example, require manual input of the information obtained as a result of the scanning and recognition process. In a simple implementation, the postage amount and postal code are displayed to the operator who enters these via the keyboard 34. The postal rate is computed and printed over the previously affixed postage and the incorrectly postaged mailpieces are outsorted as previously described. It will be further appreciated that a particularly efficient operation is obtained in the apparatus in accordance with the invention for those batches of mailpieces in which each mailpiece is anticipated to require the same amount of postage (shown at 230). For instance, in the U.S. the apparatus might be set to 29 cents for mailpieces weighing an oz. or less. In such case the mailpieces could be efficiently scanned to outsort those mailpieces carrying insufficient affixed postage with no further operator input required beyond the initial setup for the anticipated rate. In another mode of operation (shown at 240) information may be provided to the apparatus from an external source (such as a floppy disk), describing the amount of postage required by each mailpiece in a group to be processed.

The method and apparatus for verifying that the correct postage has been paid includes a mail processing machine which is adapted to receive properly oriented mail via a transport from a racer apparatus. The mail processing machine includes a scale for weighing a mailpiece having postage affixed thereto for the purpose of cancelling it with a mark which includes the actual postage which should be affixed. In a further embodiment other information necessary to calculate the necessary postage is obtained by reading the information from the mailpiece. Any discrepancies between the postage affixed and the amount of postage which should actually be paid may be noted at acceptance or seen by the carrier as the mail is delivered. A batch of mail may be sampled to select representative mailpieces in a random manner and verified to compare the calculated total of postage required based on the sample to the postal amount paid for the batch by the sender.

TECHNICAL FIELD An embodiment of the disclosure relates to techniques for generating a controlled voltage and more particularly to the methods for controlling a switching regulator. BACKGROUND A block diagram of a voltage regulator that supplies a load L through a cable C is depicted in FIG. 1 . A control system keeps the voltage generated by the converter at a constant value when changes of the input voltage Vin and/or the load L occur. Optionally, a second control system may be present to regulate the current delivered by the converter. The two control systems are mutually exclusive: if the current demanded by the load is lower than the current regulation setpoint, the voltage control system will regulate the output voltage and the current control system will be inoperative; contrarily, the current control system will take over and the voltage loop will be inoperative. Voltage control and, when present, current control use a closed-loop negative feedback: the voltage generated by the converter and current through the load, respectively V OUT and I OUT , are fed back to the error amplifiers EAV and EAC and they are compared with their references V REF and I REF , respectively. The input signals V CV , V CC to the controller come from the error amplifiers that sense the difference between reference values (V REF and I REF ) and the feedback signals (V OUT and I OUT ). Depending on the input signals, the controller generates a PWM signal that drives power switches. Through a transformer, an output rectifier and a filter, energy is transferred from the supply voltage source V IN to the load L. The diagram shown in FIG. 1 is quite general and may have several possible alternative embodiments. Typically, energy is transferred to the load through a cable C. The voltage control loop keeps the voltage Vout regulated but, depending on the output current, the voltage on the load, V LOAD , will be affected by a voltage drop along the cable, out of the control loop. Thus if a zero load regulation is to be achieved, it may be necessary to compensate the drop along the cable in some way. A simple known way of meeting this potential need is illustrated in FIG. 2 and consists in using an additional sensing wire to sense the voltage V LOAD . In this way a zero load regulation may be achieved, but an additional wire is needed. A three-wire cable is not as common as a two-wire one and may be more expensive. Another solution, that avoids the need of additional wires, is to adjust the voltage loop reference (V REF ) by an amount proportional to the average output current, the value of which can be sensed directly even with a remote load. Cable drop compensation (briefly CDC) can be performed if the value of the cable resistance R cable is known. This solution is depicted in FIG. 3 . The transfer function of the CDC block is: V′ REF =V REF +k CDC ·I OUT , where k CDC is the cable drop compensation gain and V′ REF is the adjusted reference. In the circuit of FIG. 1 , during voltage regulation, it is: V OUT =k CV ·V REF and V LOAD =V OUT −R cable ·I OUT , where k CV is the voltage loop gain, V OUT is the regulated voltage and V LOAD is the real voltage on the load. With reference to the diagram of the FIG. 3 the output voltage is: V′ OUT =k CV ·V′ REF =k CV ·( V REF +k CDC ·I OUT )= V OUT +k CV ·k CDC ·I OUT . As the resistance R cable is known by the application, the k CDC value is chosen in order to satisfy the condition V LOAD =V OUT , hence: k CV · k CDC = R cable ⇒ k CDC = R cable k CV . Typically, the output current is sensed directly. A common way of sensing the output current and adjusting the voltage reference proportionally in a non-isolated step-down switching converter is illustrated in FIG. 4 (from the STMicroelectronics AN1061 applications note, all versions of which are incorporated by reference). In particular, by connecting the resistor R K as shown in FIG. 4 , it is possible to adjust the voltage reference value by shifting the ground voltage of the IC by an amount proportional to the current I LOAD . A similar technique applied to an isolated flyback switching converter is shown in FIG. 5 (from the STMicroelectronics TSM1052 datasheet, all versions of which are incorporated by reference). Only the secondary side is shown; V OUT and I OUT are sensed and compared against their respective references; the error signal (of the loop in control) is transferred to the primary side via an optocoupler, where it is properly handled. A typical isolated flyback configuration using the optocoupler to transfer the output information from secondary side to the primary one is shown in FIG. 6 (from the STMicroelectronics Viper53 datasheet, all versions of which are incorporated by reference). There is a special class of low-cost isolated converters, in which output voltage regulation is quite loosely specified and use a simpler approach, according to which there is no sensing element or any reference on the secondary side and, therefore, no specific means for crossing the isolation barrier to transfer the error signal to the primary side, as depicted in FIG. 7 (from the STMicroelectronics Viper53 datasheet, all versions of which are incorporated by reference). In these systems, the voltage drop along the output cable adds to their inherently poor load regulation and can make unacceptable the use of such low-cost systems. In this case, a cable drop compensation circuit would make the difference. However, there is no known technique to compensate the cable resistance for this type of switching converter. SUMMARY It has been found that it is possible to use the technique of adjusting the voltage reference even in flyback switching converters that do not have any voltage or current sensing means on the secondary side, and also do not have means for transferring an error signal from the secondary side to the primary side of the converter. It has been demonstrated that the average output current delivered by the converter may be accurately estimated using signals available on the primary side, by providing a dedicated circuit block for estimating such a value. More precisely, the average output current I OUT is proportional to the product of Is and the ratio T ONSEC /T wherein I S is the secondary peak current, T ONSEC is the time during which the secondary current is flowing and T is the switching cycle. It has been found that signals accurately proportional to the ratio T ONSEC /T and to I S can be extracted from the primary side in any switching converter with primary feedback, thus it is not necessary to use dedicated sensors nor means for crossing the isolation barrier from the secondary side to the primary side. For example, a signal accurately proportional to the ratio T ONSEC /T may be produced in different alternative ways: measuring, with counters or with any other suitable digital means, the time interval T ONSEC in which the logic control signal that flags the beginning and the end of demagnetization phases is active and the duration T of the switching period; and calculating the ratio between the above times for producing a signal the level of which represents the ratio T ONSEC /T. As an alternative, a signal proportional to the ratio T ONSEC /T may be produced by integrating over each switching period the logic control signal that flags the beginning and the end of demagnetization phases. Another signal proportional to the ratio (T ONSEC /T) −1 may be obtained using the charge voltage of a filter capacitor on the primary side of the switching regulator that is discharged during each demagnetization phase by a resistor and is charged by a constant current in the remaining part of each switching period. These signals representative of the current delivered to a load are used for estimating the voltage drop on the cable that connects the regulator to the load. Therefore, it is possible to control the effective voltage on the load instead of the voltage generated on the secondary side by the switching regulator. Embodiments of the techniques herein described for estimating the output current of a flyback switching regulator without using sensing elements on the secondary side may be used also for other useful purposes. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 depicts a known architecture of a voltage regulator. FIG. 2 depicts a known architecture of a voltage regulator using an additional sensing wire. FIG. 3 depicts a known architecture of a voltage regulator with a compensation circuit for the voltage drop on the cable that connects the output of the regulator to a load. FIG. 4 depicts a known architecture of a voltage regulator. FIG. 5 depicts a known architecture of a voltage regulator. FIG. 6 depicts a known architecture of a voltage regulator. FIG. 7 depicts a known architecture of a voltage regulator. FIG. 8 is a graph of typical current waveforms in the primary side and in the secondary side of a flyback switching regulator. FIG. 9 reproduces a Zero Voltage Switching regulator disclosed in U.S. Pat. No. 6,590,789, which is incorporated by reference. FIG. 10 depicts sample waveforms of the voltage across an auxiliary winding of the circuit of FIG. 9 for several values of the current absorbed by the load. FIG. 11 reproduces a Zero Voltage Switching regulator disclosed in U.S. Pat. No. 5,729,443, which is incorporated by reference. FIG. 12 is a graph of typical waveforms of the main signals of a Zero Voltage Switching regulator of FIG. 11 . FIG. 13 depicts a first analog embodiment of a CDC circuit block for adjusting the reference voltage of a voltage error amplifier of a switching regulator. FIG. 14 depicts a first embodiment of a switching regulator that includes a CDC block for adjusting the reference voltage. FIG. 15 depicts an alternative embodiment of a switching regulator that includes a CDC block for adjusting the feedback voltage of the regulator. FIG. 16 depicts another alternative embodiment of a switching regulator that includes a CDC block for adjusting the feedback voltage of the regulator. FIG. 17 shows a first digital embodiment of a circuit for generating a signal proportional to the ratio T ONSEC /T. FIG. 18 shows an alternative digital embodiment of a circuit for generating a signal proportional to the ratio T ONSEC /T. FIG. 19 shows a first analog embodiment of a circuit for generating a signal proportional to the ratio T ONSEC /T. FIG. 20 depicts an alternative analog embodiment of a circuit for generating a signal proportional to the ratio T ONSEC /T. FIG. 21 depicts another embodiment of a switching regulator that includes the CDC block for adjusting the reference voltage and a circuit for generating a signal proportional to the ratio T ONSEC /T. DETAILED DESCRIPTION Primary and secondary sample current waveforms of a flyback switching converter working in discontinuous mode are depicted in FIG. 8 . It will be assumed that its PWM modulator uses a current mode control. The average output current I OUT is: I OUT = I S 2 · T ONSEC T , where, I S is the secondary peak current, T ONSEC is the time during which the secondary current is flowing, and T is the switching-cycle period. By adding a dedicated circuit, able to estimate the ratio T ONSEC /T, in the current mode IC controller, it is possible to calculate the I OUT , value by the above formula. This approach may be applied to any current-mode-controlled switching converter with primary feedback. In order to better understand the gist of this technique, the functioning of an off-line all-primary-sensing switching regulator, disclosed in U.S. Pat. Nos. 5,729,443 and 6,590,789 (which are incorporated by reference) will be discussed. An equivalent high-level circuit scheme of the switching regulator disclosed in U.S. Pat. No. 6,590,789 for regulating the output voltage is reproduced in FIG. 9 . An accurate image of the output voltage is obtained by sampling the voltage on the auxiliary winding immediately at the end of transformer's demagnetization phase, as illustrated in the graph of FIG. 10 . The switch Q 1 is turned on after the end of the demagnetization phase and then turned off by a comparator that monitors the source current of Q 1 using a sense resistor R S . An equivalent high level circuit scheme of the switching regulator disclosed in U.S. Pat. No. 5,729,443 for regulating the output current is reproduced in FIG. 11 . The switch Q 1 is operated by the PWM signal, set by the end of the demagnetization phase of the transformer, and reset by a comparator that monitors the source current of Q 1 through the sense resistor R S . The voltage of an auxiliary winding is used by a demagnetization block DEMAG through a protection resistor. The demagnetization block DEMAG generates a logic flag EOD that is high as long as the transformer delivers current to secondary side. Waveforms of the currents in the primary side and in the secondary side of the regulator, of the logic flag EOD , and of the current I C through the filter capacitor C during a switching period, are shown in FIG. 12 . The logic flag EOD is used to turn on and off a MOSFET switch Q 2 for discharging/charging the filter capacitor C. A resistor R in series with it absorbs a current U C /R, where U C is the voltage across the capacitor C. This capacitor C filters the charge current I REF and the discharge current (I REF −U C /R) so that U C is practically a DC voltage, that is applied to an input of the current mode comparator. At steady state, the average current I C is zero. If T ONSEC is the time during which the secondary current I S is flowing, it is: I REF · ( T - T ONSEC ) + ( I REF - U C R ) · T ONSEC = 0 , which can be simplified in: U C = R · I REF · T T ONSEC ( 1 ) The voltage U C is then used to set the peak primary current I p : I P = U C R S , which defines the peak secondary current I S : I S = n · I P = n · U C R S ( 2 ) The average output current I OUT can be expressed as: I OUT = I S 2 · T ONSEC T ( 3 ) By combining the previous equations, we obtain: I OUT = n 2 · R · I REF R S . Thus it is possible to set the average output current of the switching regulator by fixing the reference current I REF and the resistances R and R S . It has been found that a signal proportional to the output current can be generated by using signals already available in the primary side of the converter. Indeed, combining equations (1) and (3), leads to the following expression: U C = R · I REF 2 · I S I OUT ( 4 ) Hence the charge voltage of the filter capacitor contains information concerning the average output current, thus it can be used for compensating the voltage drop on the cable that connects a load to a flyback switching regulator. Moreover, during the voltage regulation, the voltage control loop signal establishes the peak primary current I p : I P = V CV R S ( 5 ) wherein V CV is the voltage generated by the error amplifier EAV (in the circuit of FIG. 1 ) proportional to the difference between the reference voltage V REF and the output voltage V OUT generated by the controller. Therefore, by combining the equations (4) and (5) it results: U C = n 2 · R · I REF R S · V CV I OUT In the above formula all the signals are known except for the I OUT value. In the IC controller is inserted a dedicated CDC block for performing the division between the signals V CV and U C in order to obtain a signal proportional to the output current: V CV U C = 2 n · R S R · I REF · I OUT ( 6 ) In an embodiment, the CDC block is analog, as depicted in FIG. 13 , and comprises an analog divider the output of which is multiplied by a constant k, a filter and an analog subtractor of the output of the filter and the reference voltage V REF . As an alternative, the CDC block could be digital, converting the signals V CV and U C in digital form, carrying out the division, subtracting the result from the voltage value V REF , and converting the result back into an analog signal. The next step is to adjust the voltage reference V REF by an amount depending on the output current, as explained previously. In fact, the CDC block is designed to implement the following transfer function: V REF ′ = V REF - k · 2 n · R S R · I REF · I OUT . The CDC block, during the output voltage regulation, introduces a positive feedback that may compromise the stability of the primary loop. For this reason a low-pass filter is preferably added, as shown in FIG. 13 . Looking at FIG. 13 it is possible to notice the analog divider, the output signal of which is multiplied by a constant k, the filter and the analog subtractor. FIG. 14 shows the architecture of an embodiment of a voltage mode converter, that includes a CDC block in the primary loop for adjusting the voltage reference value (V REF ) by an amount proportional to the output current. The new voltage loop reference is V REF ′. This allows to compensate the voltage drop along the output cable and, ideally, to achieve a zero load regulation. This technique may be applied even by modifying the feedback voltage on the capacitor C* instead of directly acting on V REF . A sample embodiment of this type is shown in FIG. 15 , where the CDC block sinks a current proportional to the output current from the feedback resistor divider in order to modify the sampled value: I CDC = k · 2 n · R S R · I REF · I OUT . Another way to modify the voltage feedback signal value is to generate a voltage proportional to the output current: V CDC = V REF - k · 2 n · R S R · I REF · I OUT and to connect a resistor R CDC as shown in the FIG. 16 . The resistor R CDC is an external component which gives the user the possibility to set the CDC gain depending on the application. Its value is calculated by the following equation: R CDC = k · 2 n · N OUT N AUX · R 1 R cable · R S R · I REF , where, n is the ratio between primary and secondary windings, N OUT is the number of the windings on the secondary, N AUX is the number of the windings on the auxiliary, R cable is the cable resistance and R S is the sensing resistor connected to the power MOSFET source. The use of that resistor is a possible way to set the CDC gain depending on the application. In fact, applying the previous embodiments, without R CDC , the same objective can be reached by trimming the constant k value. A signal proportional to the ratio T ONSEC /T may be generated by exploiting the logic control signal EOD that flags the beginning and the end of magnetization phases, for example using the embodiment of the circuit depicted in FIG. 17 . Two pulse counters COUNTER generate digital signals corresponding to the duration of the time intervals T ONSI and T−T ONSEC by counting clock pulses while the signal EOD and the inverted replica thereof are active, respectively, then a calculation block DIGITAL CALCULATOR generates a digital signal that represents the ratio T ONSEC /T, that is converted in a corresponding analog signal Vratio by a digital-to-analog converter DAC. If the CDC block can be input with digital signals, then the converter DAC is not necessary. According to an alternative embodiment, a signal proportional to the ratio T ONSEC /T may be generated by the circuit of FIG. 18 , that uses three monostable flip-flops for switching three capacitors C, C 1 and C 2 . In correspondence of the leading edge of the signal EOD , the charge voltage of the capacitor C is sampled and held on the capacitor C 1 , and the capacitor C is discharged (signal RESET). The capacitor C is charged again by the current generator IREF and its charge voltage is sampled and held on the capacitor C 2 when the signal EOD switches low (that is at the end of each demagnetization phase). Therefore, the charge voltages VC 1 and VC 2 of the capacitors C 1 and C 2 represent the duration of a period and of the magnetization phase, respectively: V C ⁢ ⁢ 1 = I REF C · T , V C ⁢ ⁢ 2 = I REF C · T ONSEC A divider generates the signal Vratio as the ratio V C2 /V C1 . The signal RESET used for discharging the capacitor C is substantially a delayed replica of the pulse T, such to zero the charge voltage of the capacitor C substantially immediately after it has been held on the capacitor C 1 . According to an alternative embodiment, the voltage Vratio may be generated by integrating the signal EOD over a switching period T, as schematically depicted in FIG. 19 . A CDC block suitable for using the voltage Vratio for adjusting the reference voltage VREF′ is depicted in FIG. 20 . This CDC block is similar to that depicted in FIG. 13 , but it has an input multiplier instead of an input divider. An embodiment of a switching regulator that employs the CDC block of FIG. 20 and a circuit for generating a voltage Vratio proportional to the ratio T ONSEC /T, such as the circuits of FIGS. 17 to 19 , is shown in FIG. 21 . The functioning of this switching regulator is evident in view of the description made referring to FIGS. 14 to 16 . Furthermore, some to all of the components of the switching regulator of FIG. 21 may be disposed on an Integrated Circuit (IC) die, and the regulated output voltage V OUT may provide power to a circuit, such as a controller processor, that is disposed on the same die or on a different die. Naturally, in order to satisfy local and specific requirements, a person skilled in the art may apply to the solution described above many modifications and alterations. Particularly, although the present subject matter has been described with a certain degree of particularity with reference to described embodiment(s) thereof, it should be understood that various omissions, substitutions and changes in the form and details as well as other embodiments are possible. Moreover, it is expressly intended that specific elements and/or method steps described in connection with any disclosed embodiment of the disclosure may be incorporated in any other embodiment as a general matter of design choice.

An embodiment of a power-supply controller comprises a switching-control circuit, an error amplifier, and a signal generator. The switching-control circuit is operable to control a switch coupled to a primary winding of a transformer, and the error amplifier has a first input node operable to receive a feedback signal, a second input node operable to receive a comparison signal, and an output node operable to provide a control signal to the switching-control circuit. The signal generator is operable to generate either the feedback signal or the comparison signal in response to a compensation signal that is isolated from a secondary winding of the transformer and that is proportional to a load current through a conductor disposed between the secondary winding and a load.

This is a continuation of application Ser. No. 858,746 filed May 2, 1986, now abandoned. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor module and, particularly, to a semiconductor module including switching devices as components of an inverter which is used in an uninterruptable constant-voltage constant-frequency (CVCF) power unit. 2. Description of the Prior Art FIG. 1 is a block diagram showing the conventional semiconductor module and its associated switching control circuit taking charge of one phase of an inverter. In the figure, a PWM control circuit 1 has its output connected to a short-circuit prevention circuit 2, which provides outputs to drive circuits 3a and 3b. The drive circuits 3a and 3b supply their outputs to a semiconductor module 4 which incorporates two serial-connected self-turn-off switching devices, such as transistors and GTOs, Q1 and Q2. FIG. 2 is a timing chart showing the input/output signals among the component blocks shown in FIG. 1. The chart includes the output signal S1 A of the PWM control circuit 1, the drive signal S1 B provided by the positive drive circuit 3a for the positive switching device Q1, the drive signal S1 C provided by the negative drive circuit 3b for the negative switching device Q2, and the output signal S1 D produced by the semiconductor module 4. Next, the operation of the above-mentioned prior art system will be described. The PWM control circuit 1 determines the timing of activating or deactivating the switching devices Q1 and Q2 which constitute a phase arm of the inverter, and produces the output signal S1 A . A high output signal S1 A operates on the drive circuit 3a to produce the drive signal S1 B by which the positive switching device Q1 turns on, while the negative switching device Q2 does not receive its drive signal S1 C from the drive circuit 3b and stays in the off state. Conversely, a low output signal S1 A does not provide the drive signal S1 A for the positive switching device Q1, causing it to stay in the off state, while the negative switching device Q2 receives the drive signal S1 C from the drive circuit 3b and turns on. In the transition of the output signal S1 A from high to low, or from low to high, namely when one switching device changes the state from on to off and another switching device from off to on, the main current in the turning-off switching device Q1 or Q2 goes off with a time lag of a carrier storage time plus a turn-off time with respect to the turn-off command by the drive signal S1 B or S1 C , resulting in an improper operating mode where both switching devices Q1 and Q2 are in the on state simultaneously (this state is termed here "vertical short-circuit"). In order to prevent the occurrence of vertical short-circuit, a short-circuit preventing circuit 2 is provided, and it causes the turning-on drive signal S1 B or S1 C to lag so that both switching devices Q1 and Q2 are given the off-command for a certain time length `t`. However, when the pulse width is narrow, as in the high-frequency PWM control, a time lag in the turn-on command causes the semiconductor module 4 to produce the output S1 D which is different in pulse width from the PWM control signal S1 A , and a theoretical output waveform which is free of specific harmonics cannot be accomplished. SUMMARY OF THE INVENTION A main object of the present invention is to provide a semiconductor module which effectively overcomes the foregoing prior art deficiency. Another object of the invention is to provide a semiconductor module which minimizes the vertical short-circuit interrupting period for serial-connected switching devices and is capable of switching at a nearest timing to the PWM control signal. Other objects and advantages of the present invention will become more apparent from the following description of the preferred embodiments taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing the conventional semiconductor module and its associated switching control circuit used for a phase arm of an inverter; FIG. 2 is a timing chart showing the input/output signals among the component blocks shown in FIG. 1; FIG. 3 is a block diagram showing an embodiment of the inventive semiconductor module and its associated switching control circuit used for a phase arm of an inverter; FIG. 4 is a timing chart showing the input/output signals among the component blocks shown in FIG. 3; and FIG. 5 is a block diagram showing another embodiment of this invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will now be described with reference to FIG. 3, in which counterparts of FIG. 1 are referred to by the common symbols. Reference numbers 5a and 5b denote logical AND gates and reference number 6 denotes a semiconductor module. The semiconductor module 6 includes transistors Q3 and Q4 functioning as serial-connected switching devices and current sensors Q5 and Q6 for detecting the presence or absence of the emitter current of the transistors Q3 and Q4, with the outputs of the sensors Q5 and Q6 being connected to the inverting input of the AND gates 5a and 5b, respectively. A diode Q 9 is connected in parallel to the switching device Q 3 and current detector Q5 and a diode Q 10 is connected in parallel to the switching device Q 4 and current detector Q6 so as to bypass the switching devices and prevent reverse currents therethrough when the potential at the emitter side of the switching device becomes positive with respect to the potential at the collector side of the switching device. The timing chart shown in FIG. 4 includes the output signal S2 A of the PWM control circuit 1, the base drive signal S2 B produced by the positive drive circuit 3a for controlling the operation of the positive switching device Q3, the base drive signal S2 C produced by the negative drive circuit 3b for controlling the operation of the negative switching device Q4, and the output signal S2 F of the semiconductor module 6. In FIG. 3, the current sensor Q5 detects the emitter current of the switching device Q3 and provides a logical output signal S2 D , while another current sensor Q6 detects the emitter current of the switching device Q4 and provides a logical output signal S2 E . The sensor output signals S2 D and S2 E have a variable transitional timing depending on the power-factor of the load circuit, and therefore are not shown in the timing chart of FIG. 4. The operation of the foregoing circuit arrangement is as follows. The PWM control circuit 1 determines the timing of switching for the switching transistors Q3 and Q4, by providing a high output S2 A to make a drive signal S2 B for turning on the transistor Q3 and providing a low output S2 A to make a drive signal S2 C for turning on the transistor Q4, as in the conventional system. The current sensors Q5 and Q6 detect the presence or absence of the emitter current of the transistors Q3 and Q4, and produce a high detection signal S2 D or S2 E or a low detection signal S2 D or S2 E in correspondence to the presence or absence of each emitter current. When the output signal S2 A of the PWM control circuit 1 makes a transition from low to high in the presence of the emitter current of the transistor Q4, the detection signal S2 E goes high, causing the AND gate 5a to produce a low output signal S2 B , and the transistor Q3 is not turned on. At the subsequent moment when the emitter current of the transistor Q4 has gone off, the detection signal S2 E becomes low, causing the AND gate 5a to produce a high output signal, and the transistor Q3 is turned on by the drive signal from the drive circuit 3a. Conversely, when the output signal S2 A of the PWM control circuit 1 makes a transition from high to low in the presence of the emitter current of the transistor Q3, the drive circuit 3b produces a low drive signal S2 C , retaining the transistor Q4 in the off state. The drive signal S2 C becomes high the moment Q3 emitter current has gone off, and the transistor Q4 is turned on. Accordingly, no time lag arises in the turn-on and turn-off operations of both switching devices in the moment of transition of one switching device from on to off and another switching device from off to on. FIG. 5 shows another embodiment of this invention, in which the semiconductor module 6 is provided therein with base drive signal bypass circuits or transistors Q7 and Q8 which are controlled internally to become conductive so that the switching device Q3 or Q4 is forced to cut off, instead of using the external interlock circuit. Although in the foregoing embodiments of FIGS. 3 and 5 the semiconductor module 6 is a transistor module, the switching devices may be other self-turn-off devices such as GTOs and MOSFETs to accomplish the same effect as described above. The present invention is intended to prevent vertical short-circuitting of two switching devices in a semiconductor module by provision of current sensors which detect the presence or absence of the main current of the switching devices. The simple inventive circuit arrangement surely prevents the improper mode of operation in which two switching devices are in the on state simultaneously. In consequence, the switching devices produce the pulse width with much fidelity to the command waveform, whereby the inverter constituted by the semiconductor modules can have the enhanced performance.

A semiconductor module includes two switching devices operated by the PWM control signal, current detectors for detecting currents through the respective switching devices, and bypass units operated by the corresponding opposite current detector for shunting the control signal to the respective switching devices to prevent activation thereof when the corresponding opposite switching device is conductive.

BACKGROUND OF THE INVENTION 1. FIELD OF THE INVENTION The present invention relates to measuring and testing equipment for semiconductor integrated circuits (ICs), and in particular to those devices which mount an IC and perform measuring and testing utilizing a measurement handler socket provided with probes which are brought into contact with outer leads arranged around the periphery of the IC mounting to achieve conduction. 2. Description of the Related Art Semiconductor integrated circuits (semiconductor devices) are subjected to various function tests after manufacture, using a measurement handler. The structures of conventional IC measuring and testing devices are shown in FIGS. 1 and 2, of which FIG. 1 is a perspective view while FIG. 2 is a side view. As shown in these drawings, a mold-receiving base 2 is provided in the central portion of a measurement handler socket (hereinafter referred to simply as a socket) 1. This mold-receiving base 2 corresponds to the shape of the mold body 5 of the IC 4 to be measured, for example a rectangular shape, and guide members 7 for guiding the mold body 5 are formed in the four sides of the rectangle. The IC 4 to be measured comprises the mold body 5 which has a top surface (upper surface) 5a and a bottom surface (lower surface) 5b, with a plurality of outer leads 6 provided protruding from the four edge surfaces around the periphery of the mold body 5. Each outer leads 6 protrudes horizontally form the edge of the mold body 5 to form a shoulder portion 6a at its root portion, is bent downward therefrom, and is then bent horizontally again at its end to form a leg portion 6b. A plurality of probes 3 are provided at the peripheries of the four sides of the mold-receiving base 2 and corresponding to the outer leads 6 of the IC 4. The mold-receiving base 2 is mounted on a substrate 9 via a spring 12. The IC 4 to be measured is suction-supported by a suction arm 11 for handling, such as a vacuum chuck or the like, on the top surface 5a thereof, is lowered onto the mold-receiving base 2 in the direction of the arrow A, the bottom surface 5b of the mold body 5 is guided in the direction of arrow B along the guide member 7, and thereby the IC 4 is set into the socket 1. FIGS. 3A to 3E are explanatory diagrams of the procedures of an IC measuring and testing method of the related art. First, as shown in FIG. 3A, the suction-supported IC 4 whose top surface 5a is raised by the suction arm 11 is aligned in a position sufficiently close to the mold-receiving base 2 above the socket 1 by an image processing or other suitable positioning means. There the vacuum of the suction arm 11 is released and the IC 4 is dropped into place. By this means, as shown in FIG. 3B, the mold body 5 of the IC 4 is seated and supported within the guide member 7 surrounding the mold-receiving base 2. In this state the end horizontal portions (leg portions) 6b of the outer leads 6 of the IC 4 are in a non-contact state separated from above the probes 3. Next, as shown in FIG. 3C, contactors 10 are lowered to push down the leg portions 6b of the outer leads 6 of the IC 4 against the resistance of the spring 12, thus causing the outer leads 6 to contact and obtain conduction with the corresponding probes 3. In this state, predetermined measuring and testing can be performed on the IC 4 by a measuring and testing circuit (not shown) connected thereto via the terminals 3a of the probes 3. Upon completion of the predetermined measuring and testing and acquisition of desired measurement data, the contactors 10 are raised and separated from the outer leads 6 as shown in FIG. 3D, by which means the outer leads 6 are separated from the probes 3. Subsequently, the suction arm 11 is lowered to suction-support the top surface 5a of the mold body 5 of the IC 4 and then raised, extracting the IC 4 from the mold-receiving base 2 as shown in FIG. 3E and transferred it to the next process. However, in the IC measuring and testing method by means of a conventional measurement handler as described above, the outer leads 6 of the IC 4 can strike against the guide members 7 of the socket 1 when the IC 4 is set in the socket 1 due to slight alignment errors or inconsistencies in the outer dimensions of the IC, leading to the possibility of deformation of the leads. This is likely to occur particularly in cases where the IC itself is large and has many pins or where the leads are miniaturized. SUMMARY OF THE INVENTION The object of the present invention is to provide an IC measuring and testing device which can overcome the disadvantage of leads deforming due to the guide members etc. of the socket striking against the outer leads of the IC when the IC is set. The present invention was designed in order to achieve this object, and is an IC measuring and testing device which comprises a measurement handler socket, provided with a mold-receiving base having around its periphery guide members corresponding to the shape of an IC mold body to be measured and probes for contacting the outer leads of the IC, and a handling means for suction-supporting the IC and mounting it in the mold-receiving base, and which performs measuring and testing of an IC mounted on the mold-receiving base by means of the handling means, wherein the guide members separate the corresponding outer leads of the IC and the end portions of the probes are arranged so as to be inserted into these separated portions. A pressure member is also provided in the present invention for applying pressure from above on the IC mounted in the mold-receiving base by the handling means, via the mold body. The present invention is further provided with guide members at the four sides of the rectangular shaped mold-receiving base. The present invention also includes a method for performing measuring and testing of the IC in the IC measuring and testing device, in which, firstly, the IC to be measured is suction-supported by the handling means, then the IC suction-supported by the handling means is mounted facing the mold-receiving base in a state where its top surface is facing downward, whereafter the root portions of the outer leads extending from the mold body are brought into contact with the probe terminal portions within the separated portions by the bottom surface of the mold body of the IC being depressed from above by the handling means, so that conduction is obtained between the outer leads and the probes. In addition, the present invention is a method for performing measuring and testing of an IC using an IC measuring and testing device wherein, firstly, the IC to be measured is suction-supported by the handling means, then the IC suction-supported by the handling means is mounted facing the mold-receiving base in a state where its top surface is facing downward, whereafter the root portions of the outer leads extending from the mold body are brought into contact with the probe terminal portions within the separated portions by the bottom surface of the mold body of the IC being subjected to pressure from above by the pressure member, so that the electrical conduction is achieved between outer leads and the probes. In the present invention, since the guide members provided around the periphery of the mold-receiving base are separated from the corresponding outer leads of the IC and the terminal portions of the probes are arranged inserted into the separation portion, the mold body is guided by the guide members when the IC to be measured is mounted in the mold-receiving base with the top surface of the IC facing downward, by which means the guide members etc. of the socket do not contact and are not deformed by the outer leads. Also in the present invention, with regard to the IC mounted in the mold-receiving base, by applying pressure on the bottom surface of the mold body of the IC from above by way of the handling means, the root portions of the outer leads are brought into contact with the probes arranged in the separation portions of the guide members and conduction can be achieved between the outer leads and probes. Further, in the present invention, with regard to the IC mounted in the mold-receiving base as described above, by applying pressure on the bottom surface of the mold body of the IC from above by means of the pressure member, the root portions of the outer leads are brought into contact with the probes arranged in the separation portions of the guide members and conduction can be attained between the outer leads and the probes. BRIEF DESCRIPTION OF THE DRAWINGS These and other features, aspects and advantages of the present invention will become better understood with reference to the following description, appended claims and accompanying drawings wherein FIG. 1 is a perspective view showing a conventional IC measuring and testing device; FIG. 2 is a cross-sectional side view of the conventional IC measuring and testing device; FIG. 3A is a cross-sectional side view of a conventional IC measuring and testing method, showing a suction-supported IC whose top surface is raised by a suction arm and aligned at a position sufficiently close to a mold-receiving base above a socket; FIG. 3B is a cross-sectional side view of a conventional IC measuring and testing method, showing the IC being dropped into place by the release of the vacuum of the suction arm so that the mold body of the IC is seated and supported within a guide member surrounding the mold-receiving base; FIG. 3C is a cross-sectional side view of a conventional IC measuring and testing method, showing contactors being lowered to push down leg portions of outer leads of the IC against the resistance of a spring, thus causing the outer leads to contact and achieve conduction with corresponding probes; FIG. 3D is a cross-sectional side view of a conventional IC measuring and testing method, showing the contactors being raised and separated from the outer leads, separating the outer leads from the probes. FIG. 3E is a cross-sectional side view of a conventional IC measuring and testing method, showing the suction arm being lowered to suction-support the top surface of the mold body of the IC and then raised, extracting the IC from the mold-receiving base and transferring it to the next process; FIG. 4 is a perspective view showing a first embodiment of an IC measuring and testing device according to the present invention; FIG. 5 is an enlarged perspective view showing the main components of the mold-receiving base 2 shown in FIG. 4; FIG. 6 is a cross-sectional side view of the device shown in FIG. 4; FIG. 7A is a cross-sectional side view of a second embodiment of the present invention, which is an IC measuring and testing method, showing the bottom surface of an IC being suction-supported by the suction arm to align the IC at a position sufficiently close to the mold-receiving base above the socket; FIG. 7B is a cross-sectional side view of the IC measuring and testing method of the second embodiment of the present invention, showing the IC being dropped into place by the release of the vacuum of the suction arm the top surface of the mold body being guided into the guide members at the periphery of the mold-receiving base with the leg portions of the outer leads facing upwards; FIG. 7C is a cross-sectional side view of the IC measuring and testing method of the second embodiment of the present invention, showing the suction arm being lowered to depress the bottom surface of the IC downwards against the resistance of the spring, thus causing the shoulder portions of the outer leads to contact the end portions of the probes and achieve electrical conduction; FIG. 7D is a cross-sectional side view of the IC measuring and testing method of the second embodiment of the present invention, showing the suction arm being raised and the IC being extracted from the socket upon completion of predetermined measuring and testing and acquisition of desired measurement data, to be transferred to the next process; FIG. 8 is a cross-sectional side view showing an example of the device of the first embodiment of the present invention applied to a DIP type IC; FIG. 9 is a cross-sectional side view showing a third embodiment of an IC measuring and testing device according to the present invention; FIG. 10 is a perspective view showing the shape of a pressure member of the third embodiment; FIG. 11A is a cross-sectional view of an IC measuring and testing method according to a fourth embodiment of the present invention, showing the pressure member disposed at the periphery of the socket being advanced in two or four directions, positioning and arranging the pressure member above the IC; FIG. 11B is a cross-sectional view of the IC measuring and testing method according to the fourth embodiment of the present invention, showing the pressure member being lowered and the bottom surface of the mold body of the IC being depressed by pressure portions to push the IC downwards against the resistance of the spring, thus causing the shoulder portions of the outer leads to contact the end portions of the probes and achieve electrical conduction; FIG. 12 is a view showing an example of the device of the third embodiment of the present invention applied to a DIP type IC; FIG. 13A is a perspective view showing the shape of a pressure member in a fifth embodiment of the present invention which is used in the IC measuring and testing device of the second embodiment; FIG. 13B is a plan view of pressure members as shown in FIG. 13A being applied to an IC, advancing from opposite directions and enabling uniform pressure to be applied to the bottom surface of the mold body. FIG. 14A is a plan view of pressure portions of a pressure member of a sixth embodiment of the present invention and the operation thereof; FIG. 14B is a side view of the pressure portions of the pressure member shown in FIG. 14A and the operation thereof; FIG. 15A is another plan view of pressure portions of the pressure member of the sixth embodiment and the pressure operation thereof; FIG. 15B is another side view of the pressure portions of the pressure member shown in FIG. 15A and the pressure operation thereof; and FIG. 16 is a drawing showing an example of a pressure member of a seventh embodiment of the present invention and the operation thereof, when applied to another type of IC. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 4 is a perspective drawing showing a first embodiment of an IC measuring and testing device according to the present invention, FIG. 5 is an enlargement of the main components thereof, and FIG. 6 is a side view thereof. As shown in the drawings, a mold-receiving base 32 is provided in the central portion of the socket 31. This mold-receiving base is of a shape corresponding to the shape of a mold body 35 of an IC to be measured, for example a rectangular shape, and guide members 37 (FIG. 5 and FIG. 6) for guiding the mold body 35 are formed on the outer edges of the four sides of this rectangular shape. These guide members 37 comprise a plurality of guide edges 37a separately arranged corresponding to the positions of a plurality of outer leads 36 of the IC 34. The IC 34 to be measured comprises the mold body 35 having a top surface (upper surface) 35a and a bottom surface (lower surface) 35b, the mold body 35 being provided a plurality of outer leads 36 extending from the four side surfaces surrounding the mold body 35. The outer leads 36 extend from the side surfaces of the mold body 35, form shoulder portions 36a at the lead root portion thereof, bend downward therefrom, and further bend horizontally at their end portions to form leg portions 36b. The mold-receiving base 32 is mounted on a substrate 39 via a spring 42. Outside the four sides of the mold-receiving base 32 are provided a plurality of probes corresponding to the outer leads 36 of the IC 34. The end portions of the probes 33 are inserted in the gaps of the separation portions of the guide members 37, i.e. between each of the abutting guide edges 37a. The IC 34 to be measured, in a state wherein it is inverted so that the top surface 35a is facing downward (the bottom surface 35b faces upward), is suction-supported at its bottom surface 35b by a suction arm 41 for handling, such as a vacuum chuck or the like. The IC 34 inverted and supported in this manner is lowered onto the mold-receiving base 32 as shown by arrow A (FIG. 4) and the upper surface 35a of the mold body is guided along the guide members 37 as shown by arrow C (FIG. 6), by which means the IC 34 is set in the socket 31. FIGS. 7A to 7D are explanatory drawings showing the procedures of an IC measuring and testing method according to a second embodiment of the present invention and utilized in the device of the first embodiment. First, as shown in FIG. 7A, the bottom surface 35b of the IC 34, which has been inverted and is at the top thereof, is suction-supported by the suction arm 41, and the IC 34 is aligned to a position sufficiently close to the mold-receiving base 32 above the socket 31 by an imaging process or another suitable positioning means. At this point, as shown in FIG. 7B, the vacuum of the suction arm 41 is released to drop the IC 34, thereby guiding the top surface 35a of the mold body 35 of the IC 34 into the guide members 37 at the periphery of the mold-receiving base 32 so that the IC 34 is set on the mold-receiving base 32 in a state where the end of the leg portions 36b of the outer leads 36 are facing upwards. In this state, the shoulder portions 36b of the outer leads 36 are separated from the probes 33, i.e. in a state wherein they are disconnected. Also, the outer leads 36 are positioned above gaps formed between the guide edges 37a (refer to FIG. 5) of the guide members 37. Further, the probes 33 are inserted in the gaps between the guide edges 37a corresponding to the outer leads 36. Next, as shown in FIG. 7C, the suction arm 41 is lowered to depress the bottom surface 35b of the IC 34 and push it downwards against the resistance of the spring 42. By this means, the shoulder portions 36a of the outer leads 36 contact the end portions of the probes 33 and achieve electrical conduction. In this state, various types of signal transmissions with a measuring and testing circuit (not shown) via the terminals 33a of the probes 33 are performed, so that predetermined measuring and testing is performed on the IC 34. Upon completion of the predetermined measuring and testing and acquisition of desired measurement data, the suction arm 41 is raised and the IC 34 is extracted from the socket 31 as shown in FIG. 7D, and is transferred to the next process. In the IC measuring and testing device of the second embodiment, since a conductive state between the outer leads 36 and the probes 33 is obtained by the suction arm 41 applying pressure from above on the bottom surface 35b of mold body 35 of the IC 34, this IC measuring and testing device corresponds to any package shape in which the IC 34 thereof has shoulder portions 36a at the root portions of the outer leads 36, i.e. not only surface-mounted type packages such as QFPs (quad flat packages), SOPs (small outline packages) and the like, but also pin-insertion type packages such as DIPs (dual inline packages), S-DIPs (shrink dual inline packages) and the like, and further, surface-mounted type packages such as QFJs (quad flat J-leaded packages), SOJs (small outline J-leaded packages) and the like. FIG. 8 shows an example wherein the present invention is applied specifically to a DIP-type IC 34 from among the various package shapes described above, this case being the same as the above-described embodiment, wherein conduction is attained between the outer leads 36 and the probes 33 by the suction arm 41 applying pressure from above on the bottom surface 35b of the mold body 35 of the IC 34. Also, in the conventional IC measuring and testing device previously described, as shown in FIG. 3, since the outer leads 6 of the IC 4 mounted on the mold-receiving base 2 are of a structure such that they are depressed by the connectors 10, during repetition of measuring and testing, solder with which the outer leads 6 are plated transfers to the connectors 10, so that maintenance for removing this solder which has become attached to the connectors 10 must necessarily be performed at regular intervals so that short circuiting and the like does not occur between the leads when continuing measuring and testing in such a state. However, because the first embodiment has a structure wherein the mold body 35 of the IC 34 mounted on the mold-receiving base 32 is depressed by the suction arm 41, and the outer leads do not make contact, the above-described maintenance is unnecessary. FIG. 9 is a side view showing a third embodiment of the IC measuring and testing device according to the present invention. In this drawing, 61 is a socket, 62 is a mold-receiving base, 63 are probes, 67 are guide members, 69 is a substrate, 71 is a suction arm, and 72 is a spring, the structures of which are the same as in the case of the first embodiment. In this third embodiment, in addition to the above-described structures, a pressure member 13, for applying pressure from above on the IC 64 mounted on the mold-receiving base 62 by the suction arm 71 via the mold body 65 thereof, are provided. FIG. 10 is a perspective view showing the shape of a pressure member of the third embodiment. As shown in the drawing, a pressure portion 73a, made from an insulating material for example, is provided on a surface of the end portion of the pressure member 73 facing the mold body 65. This pressure portion 73a is formed corresponding to the shapes of the outer leads 66 and the mold body 65 of the IC 64 to be measured. Also, an attachment hole 37b is perforated in the end portion of the pressure member 73, the pressure member 73 being fixed by a driving means (not shown) via this attachment hole 73b. At this point, the driving means described above moves the pressure member 73 in the up and down or left and right directions according to a predetermined procedure. Next, an IC measuring and testing method according to a fourth embodiment will be described. Firstly, in the same manner as is shown in FIG. 7A described above, the bottom surface 65b of the IC 64, which has been inverted and faces upwards, is suction-supported by the suction arm 71, and the IC 64 is aligned to a position sufficiently close to the mold-receiving base 62 above the socket 61 by an imaging process or another suitable positioning means. At this point, in the same manner as is shown in FIG. 7B, the vacuum of the suction arm 61 is released to drop the IC 64, thereby guiding the top surface 65a of the mold body 65 of the IC 64 into the guide members 67 at the periphery of the mold-receiving base 62 so that the IC 64 is set on the mold-receiving base 62 in a state where the end of the leg portions 66b of the outer leads 66 are facing upwards. In this state, the shoulder portions 66b of the outer leads 66 are separated from the probes 63, i.e. in a state wherein they are disconnected. Also, the outer leads 66 are positioned above gaps formed between the guide edges 67a of the guide members 67. Further, the probes 63 are inserted in the gaps between the guide edges 67a corresponding to the outer leads 66. Then, when the IC 64 has been mounted on the mold-receiving base 62, the suction arm 71 is retracted away from the socket 61. Next, as shown in FIG. 11A, the pressure member 73 disposed at the periphery of the socket 61 is advanced in two or four directions as shown by the arrows on the drawing, positioning and arranging the pressure member 73 above the IC 64. Subsequently, as shown in FIG. 11B, the pressure member 73 is lowered and the bottom surface 65b of the mold body 65 of the IC 64 is depressed by the pressure portions 73a provided at the end portions thereof to push the IC 64 downwards against the resistance of the spring 72. Thereby, the shoulder portions 66a of the outer leads 66 contact the end portions of the probes 63, and achieve electrical conduction. In this state, various types of signal transmissions with a measuring and testing circuit (not shown) via the terminals 63a of the probes 63 are performed, so that predetermined measuring and testing is performed on the IC 64. Upon completion of the predetermined measuring and testing and acquisition of desired measurement data, the pressure member 73 is raised from the state shown in FIG. 11B so that it is retracted to the periphery of the socket 71 and the IC 64 is again suction-supported by the suction arm (not shown) for IC extraction and transferred to the next process. In this way, because the third and fourth embodiments are provided with the pressure member 73 for applying via the mold body 65, pressure from above on the IC 64 mounted in the mold-receiving base 62 after the IC 64 suction-supported by the suction arm 71 is mounted in the mold-receiving base 62, by using the pressure member 73 to depress the mold body 65 and thereby achieve conduction between the outer leads 66 and the probes 63, the next IC 64 to be measured can be suction-supported by the suction arm 71 while the pressure member is depressing the mold body 65 of the currently measured IC 64 downward, then the IC 64 after measuring can be extracted from the socket 61 by a suction arm (not shown) for IC extraction, enabling the next IC 64 to be measured to be mounted in the mold-receiving base 62. Also in the third and fourth embodiments, by forming the shapes of the pressure portions 73a of the pressure member 73 to correspond to the package shape of the IC 64, in not only surface-mounted type QFP and SOP ICs, but any type of ICs, if they are ICs 64 having shoulder portions 66a at the root portions of the outer leads 66 (S-DIPs, QFJs, SOJs, etc.), such as the DIP-type IC 64 shown FIG. 12 for example, the root portions (shoulder portions 66a) of the outer leads protruding from the mold body 65 can be brought into contact with the end portions of the probes 63 within the separation portions of the guide members 67 to achieve conduction between the outer leads 66 and the probes 63, by applying pressure on the mold body 65 of the IC 64 from above with the pressure portions 73a of the pressure member 73 as shown in the drawings. Further, since the third and fourth embodiments have structures wherein the mold body 65 of the IC 64 mounted in the mold-receiving base 62 is depressed by the pressure member 73 and there is no contact with the outer leads 66 as in the previously described prior art, it is not necessary to perform maintenance to periodically remove solder attached to contactors 70. Note that in the structures of the third and fourth embodiments, the shape of the pressure member 73 need not be restricted to that shown previously in FIG. 10, but may be variously shaped according to the shapes of the mold body 65 of the IC 64 and outer leads thereof. Next, a fifth embodiment of the present invention will be described. Even if the IC is of the same QFP type as described above, a pressure portion 83a of triangular shape disposed at the end of the pressure member 83, as shown in FIG. 13A for example, can be provided as the pressure member for applying pressure on the IC from above, the pressure portions of this pressure member advancing from opposite directions of the IC mounted in the mold-receiving body as shown in FIG. 13B, enabling uniform pressure to be applied to the bottom surface 85b of the mold body 85. FIG. 14 is an explanatory drawing of a sixth embodiment of the present invention which is an example of a variation in shape of the third embodiment, FIG. 14A being a plan block drawing thereof, and FIG. 14B being a side block drawing thereof. In the drawings, the ends of the pressure member 113 are formed in a thin tapering shape, providing pressure portions 113a of protruding shape in predetermined gaps in the lower surface of the thin portion thereof. These pressure portions 113a are portions for applying pressure from directly above the mold body 105 of the IC 104 mounted in a mold-receiving base (not shown), the gaps thereof being set corresponding to the outer dimensions of the IC 104 to be measured. In other words, in the case of applying pressure on an IC 104 whose outer dimensions are small, as shown by the solid lines in the drawing, by advancing the pressure member 113 shown in FIG. 14B to a position above the IC 104 then lowering it, the pressure portions 113a provided extending from the ends as shown in FIGS. 15A and 15B can applying pressure from above on a small IC 104. On the other hand, in the case of applying pressure to an IC 104 whose outer dimensions are large as shown by the double broken lines in the drawing, in the same manner as that described above, by advancing the pressure member 113 shown in FIG. 14B to a position above the IC 104 and lowering it, the IC 104 can be depressed from above by both the pressure portions 113a provided extending from the ends as shown in FIGS. 15A and 15B and further pressure portions provided extending therefrom. In the modes of these embodiments, since one pressure member 113 can be commonly used even in cases where the outer dimensions of the IC 104 to be measured vary, it is unnecessary to perform conversion operations on the pressure member 113 with changes in the dimensions of the IC 104 to be treated. Next, a seventh embodiment of the present invention will be described. Note that in the above-described embodiments explanation was given with respect to cases where a QFP-type IC 104 was depressed. However, in cases other than this, by forming the end shapes of the pressure member 113 stepwise in thin shapes as shown in FIG. 16 for example and providing pressure portions 113a at the thin portions thereof, the pressure member 113 can be made to correspond to an SOP-type IC 124. According to the present invention as described above, since the guide members provided at the periphery of the mold-receiving base are separated corresponding to the leads of the IC and the ends of the probes are inserted and disposed in these separation portions, when the IC to be measured is mounted in the mold-receiving base in a state where the top surface thereof is facing downwards, because the mold body is guided by the guiding portions and the outer leads do not contact and deform the guide members of the socket or the like, solder junction deficiencies, short circuits between the leads and the like which give rise to lead deformation when the IC is mounted are prevented and mechanical reliability is improved, and improvement in production yields can be expected. Also, according to the present invention, with respect to the IC mounted in the mold-receiving base, by applying pressure on the bottom surface of the mold body from above with a handling means, the root portions of the outer leads are brought into contact with the probes disposed in the separation portions of the guide members and conductivity can be achieved between the outer leads and the probes, thus rendering unnecessary provision of contactors separate to the handling means as in the prior art, thereby simplifying the structure of the device. Further according to the present invention, with respect to the IC mounted in the mold-receiving base by the handling means, by applying pressure on the bottom surface of the mold body from above by means of the pressure member, the root portions of the outer leads are brought into contact with the probes disposed in the separation portions of the guide members and conductivity can be achieved between the outer leads and the probes. Consequently, since the next IC to be measured can be suction-supported by the handling means while the pressure member is applying pressure to the mold body, then the IC after measuring can be extracted from the socket, making it possible to mount the next IC to be measured in the mold-receiving base immediately thereafter, high performance measuring and testing can be expected. In addition, according to the present invention, with respect to the IC mounted in the mold-receiving base by the handling means, since the present invention is devised so that a conductive state can be achieved between the outer leads and the probes by applying pressure to the bottom surface of the mold body from above by means of the handling means or pressure member, it can be made to correspond to any package shape in which the IC has shoulder portions at the root portions of the outer leads.

An IC measuring and testing device and measuring and testing method comprising a measurement handler socket provided with mold-receiving base having guiding members corresponding to the shape of a mold body of an IC to be tested around its periphery and probes for contacting outer leads of the IC, and a suction arm for suction-supporting the IC and transferring it to the mold-receiving base, the IC measuring and testing device performing measuring and testing on the IC mounted in the mold-receiving base by means of the suction arm, the guide members corresponding to and separated from the outer leads of the IC, and terminal portions of the probes being arranged inserted into these separation portions. As a result, when the IC is set, the guide members and the like of the socket can be prevented from striking against the outer leads of the IC and deforming them.

TECHNICAL FIELD OF INVENTION [0001] The present invention relates to an intraocular lens (IOL) having variable optical power and containing two immiscible liquids. BACKGROUND [0002] During cataract surgery, the patient lens is removed and replaced by a fix plastic lens, which deprives the patient of accommodation capabilities. Intraocular lens (IOL) implants are mostly developed to replace a lens from patients that suffer from cataract. This surgery operation prevents the patient from going blind and many inventions have been developed to provide to the patient the capability of focusing on objects at various distances from the eye. [0003] Usually, the focusing capability for a healthy person is about 15 m −1 , meaning a focus from infinity to about 6 cm. This range may reduce as the patient ages down to few m −1 , or diopters. [0004] IOL implants have been developed primarily to replace the patient lens at one fixed focus. Such an implant is folded and inserted in the lens cavity through a tubular means in order to reduce as much as possible the size of the corneal incision. However, such inventions may be limited because patient is only recovering vision at a given focus. Therefore the patient is unable to focus on objects at various distances. [0005] Variable focusing IOL implants have been developed. Many of variable focusing IOL implants are based on the capability of the patient to use the eye's ciliary muscles to vary the focus and, thus, actuate the IOL implant instead of the eye's original lens. Such variable focusing IOL implants may vary the focus by a mechanical displacement of a fixed focus lens, or a lens deformation. [0006] Variable focusing may also be performed using microfluidic means. In such IOL implants, a fluid may be injected from a reservoir into the optical path to deform the interface and, thus, change the optical power of the IOL implant. In such devices, the fluid reservoir may also be connected to the ciliary muscles. Therefore, implying that the ciliary muscles will still have the strength to actuate the device. This is not always the case for patients after a certain age, and especially for patients suffering from presbyopia. [0007] Recently, Varioptic has described an IOL implant based on electrowetting actuation and made of two immiscible liquids on an insulating and hydrophobic surface (see WO2007107589). The IOL implant is encapsulated in a foldable structure, such that the device may be folded during the implantation process. However, the fluids used in the IOL device, and how to fold the device without disturbing the liquids confinement has been previously undisclosed. [0008] One object of the present disclosure is to provide an IOL implant capable of being folded and unfolded during the implantation process thus minimizing the ocular incision without disturbing the performance of the IOL device. SUMMARY [0009] In a first aspect, the invention provides an intraocular variable focus implant comprising a non-conducting liquid with a melting temperature above 0° C., a conducting liquid, a liquid interface formed by the non-conducting and conducting liquids, a first electrode in contact with the conducting liquid, a second electrode insulated from the conducting liquid, wherein the liquid interface is movable by electrowetting according to a change in a voltage applied between the first and second electrodes. [0010] In some embodiments of the first aspect, the invention provides an intraocular variable focus implant wherein the non-conducting liquid comprises a mixture of compounds wherein at least one of the compounds has a melting temperature above intraocular temperature. [0011] In some embodiments of the first aspect, the invention provides an intraocular variable focus implant wherein the non-conducing liquid has a melting temperature above 20° C. [0012] In some embodiments of the first aspect, the invention provides an intraocular variable focus implant wherein the non-conducing liquid has a melting temperature above 10° C. [0013] In some embodiments of the first aspect, the invention provides an intraocular variable focus implant comprising a first flexible transparent film comprising a hydrophilic surface in contact with the conducting liquid, and a second flexible transparent film comprising a hydrophobic surface in contact with the non-conducting liquid. [0014] In some embodiments of the first aspect, the invention provides an intraocular variable focus implant comprising one or more structural films sealed to the first and second flexible transparent films, and one or more circuit components disposed the one or more structural films, wherein the first and second electrodes are disposed on the one or more structural films, and wherein the circuit components control the voltage applied. [0015] In some embodiments of the first aspect, the invention provides an intraocular variable focus implant wherein the non-conducing liquid has a melting temperature above 20° C. [0016] In some embodiments of the first aspect, the invention provides an intraocular variable focus implant wherein the non-conducting liquid comprises a mixture of compounds and wherein at least one of the compounds has a melting temperature above intraocular temperature. [0017] In some embodiments of the first aspect, the invention provides an intraocular variable focus implant wherein one of the compounds in the non-conducting liquid acts as a membrane between the non-conducting and conducting liquids below the intraocular temperature and above 0° C. [0018] In some embodiments of the first aspect, the invention provides an intraocular variable focus implant wherein the non-conducting liquid comprises one or more compounds selected from the list consisting of a linear alkane [C n H 2n+2 ] where n is greater than 15 and less than 22, a diphenyl alkane [C n H 2n —(C 6 H 5 ) 2 ] where n is greater than 1 and less than 5, vinyl triphenylsilane, diphenylsulfide, palmitic acid, 1,4,-di-ter-butylbenzene, 1-methylfluoene, 9,10-dihydroanthracene, fluorene, methyltriphenylsilane, allyltriphenylsilane, ethyltriphenylsilane, and a cycloalkane C n H 2n where n is greater than 6 and less than 15. [0019] In some embodiments of the first aspect, the invention provides an intraocular variable focus implant wherein the non-conducting liquid comprises less than 20% by weight of phenyltrimethyl germane, diphenyldimethylgermane, or a mixture thereof. [0020] In some embodiments of the first aspect, the invention provides an intraocular variable focus implant wherein more than 80% by weight of the compounds have a melting temperature between 10° C. and 37° C. [0021] In some embodiments of the first aspect, the invention provides an intraocular variable focus implant wherein the non-conducting liquid contains less than 20% by weight of organosilanes. [0022] In some embodiments of the first aspect, the invention provides an intraocular variable focus implant wherein the intraocular variable focus implant is maintained at a temperature below the melting temperature of the compound while the compound, in liquid form, is disposed into the intraocular variable focus implant. [0023] In a second aspect, the invention provides a method of manufacturing a variable focus implant, the method comprising: disposing in the implant a non-conducting liquid with a melting temperature above 0° C., and disposing in the implant a conducting liquid, wherein a liquid interface is formed by the non-conducting and conducting liquids and the liquid interface is movable by electrowetting according to a change in a voltage applied between a first and second electrode. [0024] In some embodiments of the second aspect, the invention provides a method comprising: disposing the non-conducting liquid at a temperature above the melting temperature of the non-conducting liquid, and cooling the non-conducting liquid to below the melting temperature of the non-conducting liquid. [0025] In some embodiments of the second aspect, the invention provides a method wherein the non-conducting liquid comprises a mixture of compounds wherein at least one of the compounds has a melting temperature above intraocular temperature. [0026] In some embodiments of the second aspect, the invention provides a method comprising: disposing one compound of the mixture of compounds at a temperature above the melting temperature of the one compound, and cooling the one compound to below the melting temperature of the one compound. [0027] In some embodiments of the second aspect, the invention provides a method comprising: disposing a first compound of the mixture of compounds at a temperature above the melting temperature of the first compound, cooling the first compound to below the melting temperature of the first compound, disposing a second compound of the mixture of compounds at a temperature below the melting temperature of the first compound and above the melting temperature of the second compound, and cooling the second compound to below the melting temperature of the second compound. [0028] In some embodiments of the second aspect, the invention provides a method wherein the second compound is disposed in liquid form while the intraocular variable focus implant is maintained at a temperature below the melting temperature of the compound. [0029] In some embodiments of the second aspect, the invention provides a method wherein the non-conducing liquid has a melting temperature above 20° C. [0030] In some embodiments of the second aspect, the invention provides a method wherein the non-conducing liquid has a melting temperature above 10° C. [0031] In some embodiments of the second aspect, the invention provides a method wherein one of the compounds in the non-conducting liquid acts as a membrane between the non-conducting and conducting liquids below the intraocular temperature and above 0° C. [0032] In some embodiments of the second aspect, the invention provides a method wherein the non-conducting liquid comprises one or more compounds selected from the list consisting of a linear alkane [C n H 2n+2 ] where n is greater than 15 and less than 22, a diphenyl alkane [C n H 2n —(C 6 H 5 ) 2 ] where n is greater than 1 and less than 5, vinyl triphenylsilane, diphenylsulfide, palmitic acid, 1,4,-di-ter-butylbenzene, 1-methylfluoene, 9,10-dihydroanthracene, fluorene, methyltriphenylsilane, allyltriphenylsilane, ethyltriphenylsilane, and a cycloalkane C n H 2n , where n is greater than 6 and less than 15. [0033] In some embodiments of the second aspect, the invention provides a method wherein the non-conducting liquid comprises less than 20% by weight of phenyltrimethyl germane, diphenyldimethylgermane, or a mixture thereof. [0034] In some embodiments of the second aspect, the invention provides a method wherein more than 80% by weight of the compounds have a melting temperature between 10° C. and 37° C. [0035] In some embodiments of the second aspect, the invention provides a method wherein the non-conducting liquid contains less than 20% by weight of organosilanes. [0036] In a third aspect, the invention provides an intraocular variable focus implant comprising: a conducting liquid with a melting temperature below intraocular temperature and above 0° C., a non-conducting liquid, a liquid interface formed by the non-conducting and conducting liquids, a first electrode in contact with the conducting liquid, a second electrode insulated from the conducting liquid, wherein the liquid interface is movable by electrowetting according to a change in a voltage applied between the first and second electrodes. [0037] In some embodiments of the third aspect, the invention provides an intraocular variable focus implant wherein the conducing liquid has a melting temperature above 20° C. and bellow 37° C. [0038] In some embodiments of the third aspect, the invention provides an intraocular variable focus implant wherein the conducing liquid has a melting temperature above 10° C. and bellow 37° C. [0039] In some embodiments of the third aspect, the invention provides an intraocular variable focus implant wherein the conducting liquid comprises less than 10% by weight of a gelling agent. [0040] In some embodiments of the third aspect, the invention provides an intraocular variable focus implant wherein the gelling agent is selected from the list consisting of alginic acid, sodium alginate, potassium alginate, ammonium alginate, calcium alginate, gelatin, furcellaran or polysaccharides like agarose, carrageenan, pectin, or a mixture thereof. [0041] In some embodiments of the third aspect, the invention provides an intraocular variable focus implant wherein the conducting liquid comprises a mixture of compounds wherein at least one of the compounds has a melting temperature above intraocular temperature. [0042] In some embodiments of the third aspect, the invention provides an intraocular variable focus implant wherein one of the compounds in the conducting liquid acts as a membrane between the non-conducting and conducting liquids below the intraocular temperature and above 0° C. and melt into the conducting liquid at a temperature below intraocular temperature. [0043] In a fourth aspect, the invention provides an intraocular variable focus implant comprising: a conducting liquid, a non-conducting liquid, a compound forming a solid interface between the non conducting and conducting liquids, and being soluble in the non conducting liquid at the intraocular temperature, a first electrode in contact with the conducting liquid, a second electrode insulated from the conducting liquid, wherein the liquid interface is movable by electrowetting according to a change in a voltage applied between the first and second electrodes. [0044] In a fifth aspect, the invention provides an intraocular variable focus implant comprising: a conducting liquid, a non-conducting liquid, a compound forming a solid interface between the non conducting and conducting liquids, and being soluble in the conducting liquid at the intraocular temperature, a first electrode in contact with the conducting liquid, a second electrode insulated from the conducting liquid, wherein the liquid interface is movable by electrowetting according to a change in a voltage applied between the first and second electrodes. [0045] In some embodiments of the first aspect, the invention provides an intraocular variable focus implant wherein a solid interface is formed between conducting and non conducting liquid, said solid interface being soluble in at least one liquid. BRIEF DESCRIPTION OF DRAWINGS [0046] FIG. 1 shows an electrowetting based IOL in accordance with one or more embodiments of the claimed invention. [0047] FIG. 2 shows a schematic view of a process to fill, fold and inject an IOL using a single non-conducting fluid in accordance with one or more embodiments of the invention. [0048] FIG. 3 shows a schematic view of a process to fill, fold and inject an IOL using two separate non-conducting fluids, both having a melting temperature above intraocular temperature in accordance with one or more embodiments of the invention. [0049] FIG. 4 shows a schematic view of a process to fill, fold and inject an IOL according to the present invention, using two separate non-conducting fluids, one having a melting temperature below injection temperature, the other one having a melting temperature above injection temperature in accordance with one or more embodiments of the invention. DETAILED DESCRIPTION [0050] Specific embodiments of the invention will now be described in detail with reference to the accompanying figures. Like elements in the various figures are denoted by like reference numerals for consistency. Further, the use of “Fig.” in the drawings is equivalent to the use of the term “Figure” in the description. [0051] In the following detailed description of embodiments of the invention, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to one of ordinary skill in the art that the invention may be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating the description. [0052] Embodiments of the claimed invention relate to an intraocular liquid (IOL) lens that contains two immiscible liquids in contact, without any physical separation between liquids. IOL devices are typically scrolled or folded prior to injection in the eye, to operate as non-invasively as possible. If such an IOL is a liquid lens, the scrolling or folding operation is likely to move liquids out of their confinement area or disperse on liquid in the other due to shear stress and, thus, degrade the performance of the liquid lens. One or more embodiments of the invention relate to a liquid lens and method of manufacturing a liquid lens that remains undisturbed by scrolling or folding. [0053] European Patent EP1996968 from Varioptic is hereby incorporated by reference in its entirety. EP1996868 describes an IOL based on electrowetting actuation and made of two immiscible liquids standing on an insulating and hydrophobic surface, encapsulated in a foldable structure. [0054] EP1996968 does not disclose the fluids used in such a IOL device or how to fold the device without disturbing the liquid's confinement. One of the issues associated with IOL devices is the ability of the device to be folded in order to reduce ocular incision. The present invention provides a solution to this technical issue. [0055] In one or more embodiments of the invention, an IOL device based on electrowetting actuation, containing two immiscible liquids, enables device folding prior to injection into the patient eye without disturbing the liquid's confinement. [0056] In one or more embodiments of the invention, there are two liquids, one conducting and the other non-conducting. The non-conducting liquid is in a solid state while lens is folded and injected in the patient's eye. Then, the fluid becomes a liquid state once in the patient eye, at intraocular temperature (typically between 33° C. and 37° C. using an ambient air temperature of 20° C.). [0057] In one or more embodiments of the invention, the non-conducting liquid has a melting temperature below intraocular temperature and above 0° C. In one or more embodiments, the melting temperature of the non-conducting liquid is above 10° C. In one or more embodiments, the melting temperature of the non-conducting liquid is above 20° C. [0058] Because the non-conducting liquid is solid during folding process, it is unlikely that it will move out of its confinement area, and embodiments of the IOL device in the present invention may be injected through a reduced corneal incision while having an optimized performance. [0059] In one or more embodiments of the invention, a membrane made of a non-conducting compound, may separate the non-conducting and conducting fluid during the folding and injection process. [0060] In one or more embodiments of the invention, the conducting liquid has a melting temperature below intraocular temperature and above 0° C. In one or more embodiments, the melting temperature of the conducting liquid is above 10° C. In one or more embodiments, the melting temperature of the conducting liquid is above 20° C. [0061] In one or more embodiments of the invention, a membrane made of a polar compound, may separate the non-conducting and conducting fluid during the folding and injection process and melt in the conducting fluid below intraocular temperature. [0062] In one or more embodiments of the invention, either the conducting or non-conducting liquid may include a gelling agent, forming a gel when incorporated, or dissolved, into the liquid, and having a melting temperature below intraocular temperature and above 0° C. In one or more embodiments, the melting temperature of the jellified fluid is above 10° C. In one or more embodiments, the melting temperature of the jellified fluid is above 20° C. [0063] In one or more embodiments of the invention, the conducting liquid may contain a gelling agent like alginic acid, sodium alginate, potassium alginate, ammonium alginate, calcium alginate, gelatin, furcellaran or polysaccharides like agarose, carrageenan, or pectin. [0064] FIG. 1 shows an ophthalmic implant as described in European patent application EP1996968, in accordance with one or more embodiments of the claimed invention. The implant is made from transparent and flexible materials, examples include, but are not limited to, transparent polymers like polymethyl methacrylate (PMMA), polycarbonate, epoxies, polyesters, fluoropolymers, fluorinated ethylene propylene (FEP), PTFE (polytetrafluoroethylene), polyolefins, and polycycloolefins. Inside the implant, two liquids are trapped: the first liquid ( 4 ) is a non-polar liquid, non-conducting (or insulating liquid) forming a drop inside the capsule. The second liquid ( 5 ) is a conducting polar liquid (may be based on water solution). Both liquids are immiscible, with approximately the same density, and different indices of refraction. A first electrode ( 11 ) in the shape of a ring may be covered with a thin insulator film ( 2 ) for electrowetting actuation. In the embodiment described in FIG. 1 , the thin insulator film ( 2 ) is also playing the role of the capsule window. A second electrode ( 10 ) is in direct contact with the conducting liquid ( 5 ). [0065] Electrowetting actuation is used to activate the lens. Using a control signal, a voltage is applied between electrodes ( 10 ) and ( 11 ). The voltage induces an electrowetting effect, thus changing the contact angle of the drop of liquid ( 4 ), passing from shape A (flat drop) to shape B (a more curved drop). Because the indices of refraction of the two liquids are different, the device forms a variable power lens. In one or more embodiment of the invention, the dioptre variation may range from a few dioptres to several tens of dioptres. [0066] In one or more embodiments of the invention, the non-conducting fluid includes one or more non-conducting compounds with a melting temperature below intraocular temperature, and above the temperature during the injection process. FIG. 2 is a schematic of the process in accordance with one or more embodiments of the invention. Table 1 describes several compounds with corresponding melting temperatures. Examples of specific conducting and non-conducting fluids in accordance with one or more embodiments of the invention are given in formulations 1 and 4 (respectively conducting and non-conducing fluids), formulations 2 and 5, and formulations 3 and 6. However, the claimed invention is not limited to these specific combinations of conducting and non-conduction fluids. The liquid lens may filled with both conducting and non-conducting fluids at a temperature above melting temperature, then cooled until the non-conducting fluid is solidified. IOL may then be scrolled or folded at a temperature below the melting point temperature in preparation for surgery. Once the IOL is within the patient's eye, and unfolded, the non-conducting fluid melts and the liquid lens becomes operational. [0000] TABLE 1 List of compounds and corresponding melting temperature Name mp (° C.) Hexadecane 18.1 diphenyl methane 26 Octadécane 27.8 Nonadécane 32.1 Diphenylethane 50 Vinyltriphenylsilane 58 Diphenyl disulfide 58 Palmitic acid 62 1,4-Di-tert-butylbenzene 77 1-Methylfluorene 84 9,10-Dihydroanthracene 105 Fluorene 116 Methyltriphenylsilane <30 Allyltriphenylsilane 88 Cyclooctane 10 Cyclohexane 6.5 hexadecahydropyrene <30 Eicosane 41 Cyclododecane <30 Conducing Fluid Formulation 1 [0067] [0000] compound Weight % Sodium Bromide 0.86% water 97.64% polypropylene glycol 0.50% 1-Pentanol 1.00% measurement value density (g/cm3) 0.9968 refractive index at 589 nm at 20° C. 1.33571 Viscosity at 20° C. (mm 2 /s) 1.5065 Conducing Fluid Formulation 2 [0068] [0000] compound Weight % Sodium Bromide 1.43% water 97.07% polypropylene glycol 0.50% 1-Pentanol 1.00% measurement value density (g/cm3) 1.005 refractive index at 589 nm at 20° C. 1.337 Viscosity at 20° C. (mm 2 /s) 1.040 Conducing Fluid Formulation 3 [0069] [0000] Compound weight % Sodium Bromide 2.01% Water 96.49% polypropylene glycol 1.00% 1-Pentanol 0.50% Measurement value density (g/cm3) 1.0078 refractive index at 589 nm at 20° C. 1.3377 Viscosity at 20° C. (mm 2 /s) 1.0395 Non-Conducing Fluid Formulation 4 [0070] [0000] Compound weight % Diphenylmethane 90.00% Diphényldiméthylgermane 5.00% Hexadecane 5.00% measurement value density (g/cm3) 0.9963 refractive index at 589 nm at 20° C. 1.5701 Viscosity at 20° C. (mm 2 /s) 2.6973 Melting point (° C.) >15° C. Non-Conducing Fluid Formulation 5 [0071] [0000] compound weight % diphenylmethane 91.80% diphényldiméthylgermane 6.20% Hexadecane 2.00% measurement value density (g/cm3) 1.0052 refractive index at 589 nm at 20° C. 1.5743 Viscosity at 20° C. (mm 2 /s) 2.6778 Melting point (° C.) >15° C. Non-Conducing Fluid Formulation 6 [0072] [0000] compound weight % diphenylmethane 71.5% diphényldiméthylgermane 18.5% Hexadecane 10.0% measurement value density (g/cm3) 1.0083 refractive index at 589 nm at 20° C. 1.5621 Viscosity at 20° C. (mm 2 /s) 2.9330 Melting point (° C.) 15 [0073] In one or more embodiments of the invention, the conducting fluid comprises water and at least one organic or inorganic ion, typically at least one organic or inorganic ionic or ionizable salt, or a mixture thereof, conferring conductive properties to said fluid. [0074] In the following specification, “ionic salts” refers to salts that are totally or substantially totally dissociated (such as a bromine-anion and a cation) in water. “ionizable salts” refers to salts that are totally or substantially totally dissociated in water, after chemical, physical or physico-chemical treatment. [0075] Ions that are suitable in the present invention include both cations and anions, which may be simultaneously, but not necessarily, present together in the conducting fluid. Examples of anions include, but are not limited to, halides, e.g. chloride, bromide, iodide, sulphate, carbonate, hydrogen carbonate, acetate, and the like, as well as mixtures thereof. Examples of cations include, but are not limited to alkali, and alkaline-earth. [0076] Organic and inorganic ionic and ionizable salts are thus well known in the art, and examples of these include, but are not limited to potassium acetate, magnesium chloride, zinc bromide, lithium bromide, sodium bromide, lithium chloride, calcium chloride, sodium sulphate, sodium dibasic phosphate, sodium monobasic phosphate, phosphoric acid, acetic acid, sodium acetate, carboxylic acid (RCOOH, where R being an alkyl group C 2n H 2n+1 , with n being between 1 and 10) and corresponding sodium carboxylate salt, phosphocholine salt and the like, as well as mixtures thereof. [0077] Mixtures of one or more ionic salts together with one or more ionizable salts are also encompassed by the present invention. [0078] As already mentioned, the conductive fluid comprises an organic or inorganic ionic or ionizable salt. Said salt is dissolved in water. Water to be used in the conductive fluid should be as pure as possible, i.e. free, or substantially free, of any other dissolved components that could alter the optical properties of the optical electrowetting device, namely an optical lens driven by electrowetting. Ultra pure water is most preferably used. The concentration of the dissolved salt in the conductive fluid may vary in large proportions, keeping in mind a too high concentration may result in undesirable increase of density, refractive index, turbidity, haze, or loss of transparency for the optical device, lens or else. [0079] In one or more embodiments of the invention, the non-conducting fluid is a mixture of compounds, where at least one compound has a melting temperature above intraocular temperature, but the mixture thereof has a melting temperature below intraocular temperature. This is possible because most liquids have a melting temperature depression when mixed with other compounds, when all compounds are miscible. FIG. 3 shows a schematic of the process in accordance with one or more embodiments of the invention. Compounds having the highest melting temperature may be injected in the liquid lens at a temperature above its melting temperature then cooled to a temperature above melting point of the next compound to be injected. At this stage, the injected compounds may have been solidified as a result of the cooling. Therefore, all compounds may be injected separately. The order of injection may be from the highest melting point to the lowest melting point. When the last compound is injected, the IOL may be cooled until the non-conducting fluid is fully solidified. IOL may be folded at temperature below melting point temperature and is ready for the surgery operation. Once the IOL is within the patient eye, and unfolded, the non-conducting fluid compounds melt, mix together, and liquid lens becomes operational. One specific example of the above embodiment is the formulation 1 and 7; however, the above embodiment is not limited as such. Non-Conducing Fluid Formulation 7 [0080] [0000] compound weight % diphenylmethane 81.00% Vinyltriphenylsilane 14.00% Cyclodecane 5.00% measurement value density (g/cm3) 0.9978 [0081] FIG. 4 is a schematic of a process to fill, fold and inject an IOL using two separate non-conducting fluids, where one has a melting temperature (MP#2) below injection temperature and the other has a melting temperature (MP#1) above injection temperature, but below the intraocular temperature in accordance with one or more embodiments of the invention. The fluid having the lowest melting temperature, below injection temperature, is injected in the liquid lens at a temperature above its melting temperature, and then cool down until solidification. That fluid is kept at a temperature below melting temperature of the other compounds. Then a fluid having a melting temperature between the injection temperature and the intraocular temperature is injected and, thus, solidified at the surface of the first injected compounds. Therefore, in accordance with one or more embodiments of the invention, the fluids may be injected separately with the fluid having the highest melting temperature physically located at the interface between the conducting fluid and the other non-conducting fluid. Examples of the conducting and non-conducting fluids that may be used include, but are not limited to, the formulations 1 and 8 and formulations 3 and 9. Non-Conducing Fluid Formulation 8 [0082] [0000] compound weight % Phenyltrimethylgermane 55%   SIP 6827,0 25%   Hexadecane 20%   measurement value density (g/cm3) 0.9980 refractive index at 589 nm at 20° C. 1.4744 Viscosity at 20° C. (mm 2 /s) 1.8834 Non-Conducing Fluid Formulation 9 [0083] [0000] compound weight % diphényldiméthylgermane 52.50% SIP 6827,0 17.50% Hexadecane 30.00% measurement value density (g/cm3) 1.0080 refractive index at 589 nm at 20° C. 1.5067 Viscosity at 20° C. (mm 2 /s) 4.0537 [0084] In one or more embodiment of the present invention, the non conducting fluid is injected in the liquid lens at a temperature above its melting temperature, and then cool down until solidification. A further compound is then deposited on the solidified non-conducting fluid prior to the conducting fluid injection to form a solid membrane. The membrane remains solid during the folding process and injection but is soluble in the conducting or the non-conducting fluid at intraocular temperature after injection in the patient's eye. [0085] In one or more embodiment of the present invention, the solid membrane is made of water soluble polymers like hydroxyethylcellulose, ethylcellulose polymers, cellulose ethers, Poly(Acrylic Acids), Polyvinyl alcohol, or water soluble resins, or hydrocarbon soluble polymers. [0086] In one or more embodiment of the present invention, the solid membrane formed between the conducting and non conducting fluids is made soluble in fluids by irradiation during the capsulotomy operation. [0087] The IOL may then be folded at temperature below melting point temperature of the compounds at the interface and warmed up at the injection temperature. The fluid at the interface may act as a membrane between the conducting fluid and the other non-conducting fluid that has a melting temperature below the injection temperature. At this point, the IOL is ready for surgical implantation. Once the IOL is within the patient's eye and unfolded, the non-conducting fluids may melt and mix together. At this point, the liquid lens becomes operational. [0088] In one or more embodiments of the invention, the insulating coating may be made of poly-para-xylylene linear polymers, for example, Parylene C; Parylene N, Parylene VT4, and Parylene HT. [0089] In one or more embodiments of the invention, the insulating coating may be coated with a thin layer of a low surface energy coating such as Teflon® or Fluoropel®. [0090] Table 1 is a list of compounds that may be used in the present invention. [0091] In one or more embodiments of the invention, the non conductive fluid may contain a linear alkane (C n H 2n+2 , where 22>n>15, such as hexadecane, nonadecane, eicosane), a diphenyl alkane (C 2 H 2n —(C 6 H 5 ) 2 , where 5>n>1, such as diphenylmethane, diphenylethane), or vinyl triphenylsilane. [0092] In one or more embodiments of the invention, the non-conductive fluid may contain one or more of the following specific compounds: diphenylsulfide, palmitic acid, 1,4-Di-ter-butylbenzene, 1-methylfluorene, 9,10-Dihydroanthracene, and Fluorene. [0093] In one or more embodiments, the non-conductive fluid may contain one or more cycloalkane C n H 2n , where 6<n<15, such as cyclooctane, cyclohexane, or cyclododecane. [0094] In one or more embodiments, the non-conductive fluid may contain one or more organosilanes of formula Si—(R) 4 , where at least three of the R groups are represented independently by (hetero)aryl, (hetero)arylalkyl, (hetero)arylalkenyl and (hetero)arylalkynyl. In such embodiments, the at least one of the R groups may be an alkyl (C n H 2n+1 ) or alkene group (C n H 2n−1 ), where n=1, 2 or 3. Examples include, but are not limited to methyltriphenylsilane, allyltriphenylsilane, and ethyltriphenylsilane. [0095] The non-conductive fluid may contain one or more germane based species, for example hexamethyldigermane, diphenyldimethylgermane, and phenyltrimethyl-germane. [0096] Table 2 describes mixtures of compounds depending on temperature and indicates when mixture is in solid and liquid state in accordance with one or more embodiments of the invention. The solid state should be used during folding and injection. In particular Table 2 demonstrates that a small amount of compound having a very low melting temperature (for example <20° C. for phenyltrimethyl germane) mixed with a large amount of a high melting temperature compound (for example diphenylmethane) will result in a mixture with a melting temperature in the required range, i.e. between 10° C. and 32° C. [0000] TABLE 2 State diagram for various mixtures of non conducting fluids (solid: S; Liquid: L) Composition −20° C. −2° C. +10° C. +15° C. +18° C. +25° C. Diphenylmethane S S S S S S 10% phenylgermane + 90% diphenylmethane S S S S + L S + L L 30% phenylgermane + 70% diphenylmethane S S + L S + L L L L 70% phenylgermane + 30% diphenylmethane S + L S + L S + L L L L Phenylgermane L L L L L L 5% diphenylgermane + 95% diphenylmethane S S S S + L S + L L 10% diphenylgermane + 90% diphenylmethane S S S + L S + L S + L L 20% diphenylgermane + 80% diphenylmethane S S S + L S + L S + L L formulation 4 S S S S + L S + L L formulation 6 S S S S + L L L [0097] Embodiments of the invention may be used in any application that using a device containing two immiscible liquids, such that the liquids are contact with each other, and the device is folded during the application at a given temperature, and then unfolded at another temperature above the first temperature, where the liquids must be confined in a given volume, when the performance of the device may be disturbed and/or lowered if liquids are temporarily mixed during the folding and unfolding process. [0098] While the invention has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims.

According to a first aspect, the invention relates to an intraocular variable focus implant comprising a non-conducting liquid with a melting temperature above 0° C., a conducting liquid, a liquid interface formed by the non-conducting and conducting liquids, a first electrode in contact with the conducting liquid, a second electrode insulated from the conducting liquid, wherein the liquid interface is movable by electro wetting according to a change in a voltage applied between the first and second electrodes.

[0001] This nonprovisional application claims the benefit of U.S. provisional application No. 60/174,601 entitled “Map Decoding In Channels With Memory” filed on Jan. 5, 2000. The Applicant of the provisional application is William Turin (Attorney Docket No. 105038). The above provisional application is hereby incorporated by reference including all references cited therein. BACKGROUND OF THE INVENTION [0002] 1. Field of Invention [0003] This invention relates to iterative decoding of input sequences. [0004] 2. Description of Related Art [0005] Maximum a posteriori (MAP) sequence decoding selects a most probable information sequence X 1 T =(X 1 , X 2 , . . . , X T ) that produced the received sequence Y 1 T =(Y 1 , Y 2 , . . . , Y T ). For transmitters and/or channels that are modeled using Hidden Markov Models (HMM), the process for obtaining the information sequence X 1 T that corresponds to a maximum probability is difficult due to a large number of possible hidden states as well as a large number of possible information sequences X 1 T . Thus, new technology is needed to improve MAP decoding for HMMs. SUMMARY OF THE INVENTION [0006] This invention provides an iterative process to maximum a posteriori (MAP) decoding. The iterative process uses an auxiliary function which is defined in terms of a complete data probability distribution. The MAP decoding is based on an expectation maximization (EM) algorithm which finds the maximum by iteratively maximizing the auxiliary function. For a special case of trellis coded modulation, the auxiliary function may be maximized by a combination of forward-backward and Viterbi algorithms. The iterative process converges monotonically and thus improves the performance of any decoding algorithm. [0007] The MAP decoding decodes received inputs by minimizing a probability of error. A direct approach to achieve this minimization results in a complexity which grows exponentially with T, where T is the size of the input. The iterative process avoids this complexity by converging on the MAP solution through repeated use of the auxiliary function. BRIEF DESCRIPTION OF THE DRAWINGS [0008] The invention is described in detail with reference to the following figures where like numerals reference like elements, and wherein: [0009] [0009]FIG. 1 shows a diagram of a communication system; [0010] [0010]FIG. 2 shows a flow chart of an exemplary iterative process; [0011] [0011]FIGS. 3-6 show state trajectories determined by the iterative process; [0012] [0012]FIG. 7 shows an exemplary block diagram of the receiver shown in FIG. 1; [0013] [0013]FIG. 8 shows a flowchart for an exemplary process of the iterative process for a TCM example; and [0014] [0014]FIG. 9 shows step 1004 of the flowchart of FIG. 8 in greater detail. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS [0015] [0015]FIG. 1 shows an exemplary block diagram of a communication system 100 . The communication system 100 includes a transmitter 102 , a channel 106 and a receiver 104 . The transmitter 102 receives an input information sequence I 1 T (i.e., I 1 , I 2 , . . . , I T ) of length T, for example. The input information sequence may represent any type of data including analog voice, analog video, digital image, etc. The transmitter 102 may represent a speech synthesizer, a signal modulator, etc.; the receiver 104 may represent a speech recognizer, a radio receiver, etc.; and the channel 106 may be any medium through which the information sequence X 1 T (i.e., X 1 , X 2 , . . . , X T ) is conveyed to the receiver 104 . The transmitter 102 may encode the information sequence I 1 T and transmit encoded information sequence X 1 T through the channel 106 and the receiver 104 receives information sequence Y 1 T (i.e., Y 1 , Y 2 , . . . , Y T ). The problem in communications is, of course, to decode Y 1 T in such a way as to retrieve I 1 T . [0016] Maximum a posteriori (MAP) sequence decoding is a technique that decodes the received sequence Y 1 T by minimizing a probability of error to obtain X 1 T (and if a model of the transmitter 102 is included, to obtain I 1 T ). In MAP, the goal is to choose a most probable X 1 T that produces the received Y 1 T . The MAP estimator may be expressed by equation 1 below. X ^ 1 T = arg     max X 1 T  Pr  ( X 1 T , Y 1 T ) ( 1 ) [0017] where Pr(·) denotes a corresponding probability or probability density function and {circumflex over (X)} 1 T is an estimate of X 1 T . Equation 1 sets {circumflex over (X)} 1 T to the X 1 T that maximizes Pr(X 1 T ,Y 1 T ). The Pr (X 1 T , Y 1 T ) term may be obtained by modeling the channel 106 of the communication system 100 using techniques such as Hidden Markov Models (HMMs). An input-output HMM λ=(S,X,Y,π,{P(X,Y)}) is defined by its internal states S={1,2, . . . n}, inputs X, outputs Y, initial state probability vector π, and the input-output probability density matrices (PDMs) P(X,Y), XεX, YεY. The elements of P(X,Y), p ij (X,Y)=Pr(j,X,Y|i), are conditional probability density functions (PDFs) of input x and corresponding output y after transferring from the state i to state j. It is assumed that the state sequence S 0 t =(S 0 , S 1 , . . . , S t ), input sequence X 1 t =(X 1 ,X 2 , . . . X t ), and output sequence Y 1 t =(Y 1 ,Y 2 , . . . , Y t ) possess the following Markovian property Pr(S t , X t , Y t |S 0 t−1 , X 1 t−1 , Y 1 t−1 )═Pr(S t , X t , Y t |S t−1 ). [0018] Using HMM, the PDF of the input sequence X 1 T and output sequence Y 1 T may be expressed by equation 2 below: p T  ( X 1 T , Y 1 T ) = π  ∏ i = 1 T     P  ( X i , Y i )  1 ( 2 ) [0019] where 1 is a column vector of n ones, π is a vector of state initial probabilities, and n is a number of states in the HMM. Thus, the MAP estimator when using HMM may be expressed by equation 3 below: X ^ 1 T = arg     max X 1 T  [ π  ∏ i = 1 T     P  ( X i , Y i )  1 ] ( 3 ) [0020] The maximization required by equation 3 is a difficult problem because all possible sequences of X 1 T must be considered. This requirement results in a complexity that grows exponentially with T. This invention provides an iterative process to obtain the maximum without the complexity of directly achieving the maximization by evaluating equation 2 for all possible X 1 T , for example. In the iterative process, an auxiliary function is developed whose iterative maximization generates a sequence of estimates for X 1 T approaching the maximum point of equation 2. [0021] The iterative process is derived based on the expectation maximization (EM) algorithm. Because the EM algorithm converges monotonically, the iterative process may improve the performance of any decoding algorithm by using its output as an initial sequence of the iterative decoding algorithm. In the following description, it is assumed that HMM parameters for the channel 106 and/or the transmitter 102 are available either by design or by techniques such as training. [0022] The auxiliary function may be defined in terms of a complete data probability distribution shown in equation 4 below. Ψ  ( z , X 1 T , Y 1 T ) = π i o  ∏ i = 1 T     p i t - 1  i t  ( X t , Y t ) , ( 4 ) [0023] where z=i 0 T is an HMM state sequence, π i 0 is an initial probability vector for state i 0 , and p ij (X,Y) are the elements of the matrix P(X,Y). The MAP estimator of equation 1 can be obtained iteratively by equations 5-9 as shown below. X 1 , p + 1 T = arg     max X 1 T  Q  ( X 1 T , X 1 , p T ) , p = 0 , 1 , 2 , … ( 5 ) [0024] where p is a number of iterations and Q(X i t , X i,p t ) is the auxiliary function which may be expressed as Q  ( X 1 T , X 1 , p T ) = ∑ z     Ψ  ( z , X 1 , p T , Y 1 T )  log  ( Ψ  ( z , X 1 T , Y 1 T ) ) . ( 6 ) [0025] The auxiliary function may be expanded based on equation 4 as follows: Q  ( X 1 T , X 1 , p T ) = ∑ t = 1 T     ∑ i = 1 n     ∑ j = 1 n     γ t , ij  ( X 1 , p T )  log  ( p ij  ( X t , Y t ) ) + C ( 7 ) [0026] where C does not depend on X 1 T , n is a number of states in the HMM and γ t,ij (X 1,p T )=α i (X 1,p t−1 , Y 1 t−1 ) p ij (X t,p , Y t )β j (X t+1,p T , Y t+1 T )   (8) [0027] where α i (X 1,p t , Y 1 t ) and β j (X t+1,p T , Y t+1 T )are the elements of the following forward and backward probability vectors    α  ( X 1 t , Y 1 t ) = π  ∏ i = 1 T     P  ( X i , Y i ) , and   β ( X t + 1 T , Y t + 1 T ) = ∏ i = t + 1 T     P  ( X i , Y i )  1. ( 9 ) [0028] Based on equations 5-9, the iterative process may proceed as follows. At p=0, an initial estimate of X t,0 T is generated. Then, Q(X 1 T ,X 1,0 T ) is generated for all possible sequences of X 1 T . From equations 7 and 8, Q(X 1 T , X 1,0 T ) may be evaluated by generating γ t,ij (X 1,0 T ) and log (p ij (X t , Y t )) for each t, i, and j. γ t,ij (X 1,0 T ) may be generated by using the forward-backward algorithm as shown below: α(X 1,p 0 , Y 1 0 )=π, α(X 1,p t , Y 1 t )=α(X 1,p t−1 , Y 1 t−1 )P(X t,p , Y t ), t= 1,2, . . . T β(X T+1,p T , Y T+1 T )=1, β(X t,p T , Y t T )═P(X t,p , Y t )β(X t+1,p T , Y t+1 T ), t=T− 1, T− 2, . . . ,1 [0029] Log (p ij (X t ,Y t )) is generated for all possible X t for t=1, 2, . . . , T and the (X t )s that maximize D(X 1 T , X 1,0 T ) are selected as X 1,1 T . After X 1,1 T is obtained, it is compared with X 1,0 T . If a measure D(X 1,1 T , X 1,0 T ) of difference between the sequences exceeds a compare threshold, then the above process is repeated until the difference measure D(X 1,p T , X 1,p−1 T ) is within the threshold. The last X 1,p T for p iterations is the decoded output. The measure of difference may be an amount of mismatch information. For example, if X 1 T is a sequence of symbols, then the measure may be a number of different symbols between X 1,p T and X 1,p−1 T (Hamming distance); if X 1 T is a sequence of real numbers, then the measure may be an Euclidean distance D(X 1,p T , X 1,p−1 T )=[Σ i=1 T (X i,p −X i,p−1 ) 2 ] 1/2 . [0030] [0030]FIG. 2 shows a flowchart of the above-described process. In step 1000 , the receiver 104 receives the input information sequence Y 1 T and goes to step 1002 . In step 1002 , the receiver 104 selects an initial estimate for the decode output information sequence X 1,0 T and goes to step 1004 . In step 1004 , the receiver 104 generates γ t,ij (X 1,p T ) where p=0 for the first iteration and goes to step 1006 . In step 1006 , the receiver 104 generates all the log (p ij (X t , Y t )) values and goes to step 1008 . [0031] In step 1008 , the receiver 104 selects a sequence X 1,p+1 T that maximizes Q(X 1,p+1 T , X 1,p T ) and goes to step 1010 . In step 1010 , the receiver 104 compares X 1,p T with X 1,p+1 T . If the compare result is within the compare threshold, then the receiver 104 goes to step 1012 ; otherwise, the receiver 104 returns to step 1004 and continues the process with the new sequence X 1,p+1 T . In step 1012 , the receiver 104 outputs X 1,p+1 T and goes to step 1014 and ends the process. [0032] The efficiency of the above described iterative technique may be improved if the transmitted sequence is generated by modulators such as a trellis coded modulator (TCM). A TCM may be described as a finite state machine that may be defined by equations 10 and 11 shown below. S t+1 =f t (S t , I t )   (10) X t =g t (S t , I t )   (11) [0033] Equation 10 specifies the TCM state transitions while equation 11 specifies the transmitted information sequence based on the state and the input information sequence. For example, after receiving input I t in state S t , the finite state machine transfers to state S t+1 based on S t and I t as shown in equation 10. The actual output by the transmitter 102 is X t according to equation 11. Equation 10 may represent a convolutional encoder and equation 11 may represent a modulator. For the above example, the transmitter output information sequence X 1 T may not be independent even if the input information sequence I 1 T is independent. [0034] In equation 15, the log(p ij (Y t ,X t )) term may be analyzed based on the TCM state transitions because the information actually transmitted X t is related to the source information I t by X t =g t (S t , I t ). This relationship between X t and I t forces many elements p ij (Y t ,X t ) of P (Y t ,X t ), to zero since the finite state machine (equations 10 and 11) removes many possibilities that otherwise must be considered. Thus, unlike the general case discussed in relation to equations 5-9, evaluation of p ij (Y t ,X t ) may be divided into a portion that is channel related and another portion that is TCM related. The following discussion describes the iterative technique in detail for the TCM example. [0035] For a TCM system with an independent and identically distributed information sequence, an input-output HMM may be described by equations 12 and 13 below. P(X t , Y t )=└ p s t s t+1 P c (X t |Y t )┘,   (12) [0036] where p S t  S t + 1 = { Pr  ( I t ) 0  if     S t + 1 = f t  ( S t , I t ) otherwise ( 13 ) [0037] P c (Y t |X t ) is the conditional PDM of receiving Y t given that X t has been transmitted for the HMM of a medium (channel) through which the information sequence is transmitted; p s t s t+1 is the probability of the TCM transition from state S t to state S t+1 , and Pr(I t ) is the probability of an input I t . Thus, equation 2 may be written as p T  ( I 1 T , Y 1 T ) = π c  ∏ i = 1 T     p s t  s t + 1  P c  ( Y t | X t )  1 , [0038] where π c is a vector of the initial probabilities of the channel states, X t =g t (S t ,I t ), and the product is taken along the state trajectory S t+1 =f t (S t ,I t ) for t=1, 2, . . . , T. [0039] If all elements of the input information sequence are equally probable, then the MAP estimate may be expressed by equation 14 below. I ^ 1 T = arg  max I 1 T  π c  ∏ t = 1 T  P c  ( Y t  X t )  1 , ( 14 ) [0040] The auxiliary function may be expressed by equations 15-17 below corresponding to equations 7-9 above. Q  ( I 1 T , I 1 , p T ) = ∑ t = 1 T  ∑ i = 1 n  ∑ j = 1 n  γ t , ij  ( I 1 , p T )  log  ( p ij  ( Y t  X t ) ) + C ( 15 ) [0041] where X t =g t (S t ,I t ) and γ t,ij (I 1,p T )=α i (Y 1 t−1 |I 1,p t ) p c,ij (Y t |X t,p )β j (Y t+1,p T |I t+1,p T )   (16) [0042] α i (Y 1 T−1 |I 1,p t−1 ) and β j (Y t+1,p T |I t′1,p T ) are the elements of the forward and backward probability vectors α  ( Y 1 t  I 1 t ) = π c  ∏ i = 1 t  P c  ( Y i  X i )     and   β  ( Y t + 1 T  I t + 1 T ) = ∏ i = t + 1 T  P c  ( Y i  X i )  1 ( 17 ) [0043] From equation 15, the Viterbi algorithm may be applied with the branch metric m  ( I t ) = ∑ i = 1 n  ∑ j = 1 n  γ t , ij  ( I 1 , p T )  log     p c , ij  ( Y t  X t ) , t = 1 , 2 , …    , T ( 18 ) [0044] to find a maximum of Q(I 1 T , I 1,p T ) which can be interpreted as a longest path leading from the initial zero state to one of the states S T where only the encoder trellis is considered. The Viterbi algorithm may be combined with the backward portion of the forward-backward algorithm as follows. [0045] 1. Select an initial source information sequence I 1,0 T =I 1,0 , I 2,0 , . . . , I T,0 [0046] 2. Forward part: [0047] a. set α(Y 1 0 |I 1 0 )=π, where π is an initial state probability estimate; and [0048] b. for t=1, 2, . . . , T, compute X t,p =g t (S t ,I t,p ), α(Y 1 t |I 1,p t )=α(Y 1 t−1 |I 1,p t−1 )P c (Y t |X 1,p ), [0049] where I 1,p t is a prior estimate of I 1 t . [0050] 3. Backward part: [0051] a. set β(Y T+1 T |I T+1,p T )=1 and last state transition lengths L(S T ) to 0 for all the states; [0052] for t=T,T−1, . . . , 1 compute: [0053] b. X t =g t (S t ,I t ), [0054] c. γ t,ij (I 1,p T )=α i (Y 1 t−1 |I 1,p t−1 )p c,j (Y t |X t,p )β j (Y t+1 T |I t+1,p T ), [0055] d. L  ( S t ) = max I t  { L  ⌊ f t  ( S t , I t ) ⌋ + m  ( I t ) } . [0056] This step selects the paths with the largest lengths (the survivors). [0057] e. I ^ t  ( S t ) = arg  max I t  { L [ f t  ( S t , I t ) ] + m  ( I t ) } . [0058] This step estimates I t corresponding to the state S t by selecting the I t of the survivor in step d. [0059] β(Y t T , I t,p T )=P c (Y t |X t,p )β(Y t+1 T |X t+1,p T ). [0060] g. End (of “for” loop). [0061] 4. Reestimate the information sequence: I t,p+1 =Î 1 (Ŝ t ), Ŝ t+1 =f t (Ŝ t ,I t,p+1 ), t= 1,2, . . . , T where Ŝ 1 =0; and [0062] 5. If I t,p+1 ≠I t,p , go to step 2; otherwise decode the information sequence as I t,p+1 T . [0063] [0063]FIGS. 3-6 show an example of the iterative process discussed above where there are four states in the TCM and T=5. The dots represent possible states and the arrows represent a state trajectory that corresponds to a particular information sequence. The iterative process may proceed as follows. First, an initial input information sequence I 1,0 5 is obtained. I 1,0 5 may be the output of an existing decoder or may simply be a guess. [0064] The Viterbi algorithm together with the backward algorithm may be used to obtain a next estimate of the input information sequence I 1,1 5 . This process begins with the state transitions between t=4 and t=5 by selecting state transitions leading to each of the states s0-s3 at t=4 from states at t=5 that have the largest value of the branch metric L(S 4 )=m(I 5 ) of equation 18 above. Then, the process moves to select state transitions between the states at t=3 and t=4 that have the largest cumulative distance L(S 3 )=L(S 4 )+m(I 4 ). This process continues until t=0 and the sequence of input information I 1 5 corresponding to the path connecting the states from t=0 to t=5 that has the longest path L  ( S 0 ) = ∑ t = 1 5  m  ( I t ) [0065] is selected as the next input information sequence I 1,1 5 . [0066] For the example in FIG. 3, state transitions from the states at t=4 to all the states at t=5 are considered. Assuming that the (I t )s are binary, then only two transitions can emanate from each of the states at t=4: one transition for I 5 =0 and one transition for I 5 =1. Thus, FIG. 3 shows two arrows terminating on each state at t=4 (arrows are “backwards” because the backward algorithm is used). State transitions 301 and 302 terminate at state s0; state transitions 303 and 304 terminate at state s1; state transitions 305 and 306 terminate at state s2; and state transitions 307 and 308 terminate at state s3. [0067] The branch metric m(I t ) of equation 18 represents a “distance” between the states and is used to select the state transition that corresponds to the longest path for each of the states s0-s3 at t=4: m  ( I 5 ) =  ∑ i  ∑ j  γ 5 , ij  ( X 1 , 0 5 )  log     p ij  ( X 5 , Y 5 ) =  ∑ i  ∑ j  α i  ( X 1 , 0 4 , Y 1 4 )  p ij  ( X 5 , 0 , Y 5 )  β j  ( X 6 , 0 5 , Y 6 5 )  log     p ij  ( Y 5  X 5 ) , ( 19 ) [0068] where β j (X 6.0 5 , Y 6 5 )=1, and X 5 =g 5 (S 5 , I 5 ) by definition. There is an I 5 that corresponds to each of the state transitions 301 - 308 . For this example, L(S 4 )=m(I 5 ) corresponding to odd numbered state transitions 301 - 307 are greater than that for even numbered state transitions 302 - 308 . Thus, odd numbered state transitions are “survivors.” Each of them may be part of the state trajectory that has the longest path from t=0 to t=5. This transition (the survivor) is depicted by the solid arrow while the transitions with smaller lengths are depicted by dashed lines. [0069] The state sequence determination process continues by extending the survivors to t=3 as shown in FIG. 4 forming state transitions 309 - 316 . The distance between state transitions for each of the states are compared based on L(S 4 )+m(I 4 ), where m(I 4 ) is shown in equation 20 below. m  ( I 4 ) =  ∑ i  ∑ j  γ 5 , ij  ( X 1 , 0 5 )  log     p ij  ( X 4 , Y 4 ) =  ∑ i  ∑ j  α i  ( X 1 , 0 3 , Y 1 3 )  p ij  ( X 4 , 0 , Y 4 )  β j  ( X 5 , 0 , Y 5 )  log     p ij  ( Y 4  X 4 ) . ( 20 ) [0070] For this example, the distances corresponding to the odd numbered state transitions 309 - 315 are longer than distances corresponding to even numbered state transitions 310 - 316 . Thus, the paths corresponding to the odd numbered state transitions are the survivors. As shown in FIG. 4, the state transition 301 is not connected to any of the states at t=3 and thus is eliminated even though it was a survivor. The other surviving state transitions may be connected into partial state trajectories. For example, partial state trajectories are formed by odd numbered state transitions 307 - 309 , 303 - 311 , 303 - 313 and 305 - 315 . [0071] The above process continues until t=0 is reached as shown in FIG. 5 where two surviving state trajectories 320 - 322 are formed by the surviving state trajectories. All the state trajectories terminate at state zero for this example because, usually, encoders start at state zero. As shown in FIG. 6, the state trajectory that corresponds to the longest cumulative distance is selected and the input information sequence I 1 5 (via S t+1 =f t (S t ,I t ) that corresponds to the selected trajectory is selected as the next estimated input information sequence Î 1,1 5 . For this example, the state trajectory 320 is selected and the input information sequence I 1 5 corresponding to the state trajectory 320 is selected as Î 1,1 5 . [0072] [0072]FIG. 7 shows an exemplary block diagram of the receiver 104 . The receiver 104 may include a controller 202 , a memory 204 , a forward processor 206 , a backward processor 208 , a maximal length processor 210 and an input/output device 212 . The above components may be coupled together via a signal bus 214 . While the receiver 104 is illustrated using a bus architecture, any architecture may be suitable as is well known to one of ordinary skill in the art. [0073] All the functions of the forward, backward and maximal length processors 206 , 208 and 210 may also be performed by the controller 202 which may be either a general purpose or special purpose computer (e.g., DSP). FIG. 7 shows separate processors for illustration only. The forward, backward maximal length processors 206 , 208 and 210 may be combined and may be implemented by using ASICs, PLAs, PLDs, etc. as is well known in the art. [0074] The forward processor 206 generates the forward probability vectors α i (X 1,p t−1 , Y 1 t−1 ) herein referred to as α i . For every iteration, when a new X 1,p T (or I 1,p T ) is generated, the forward processor 206 may generate a complete set of α i . [0075] The backward processor 208 together with the maximal length processor 210 generate a new state sequence by searching for maximal length state transitions based on the branch metric m(I t ). Starting with the final state transition between states corresponding to t=T−1 and t=T, the backward processor generates ⊕(X t+1,p T , Y t+1 T ) (hereinafter referred as β j ) as shown in equation 8 for each state transition. [0076] The maximal length processor 210 generates m(I t ) based on the results of the forward processor 206 , the backward processor 208 and p ij (X t ,Y t ). After generating all the m(I t )s corresponding to each of the possible state transitions, the maximal length processor 210 compares all the L(S t )+m(I t )s and selects the state transition that corresponds to the largest L(S t )+m(I t ), and the I t (via S t+ =f t (S t , I t )) that corresponds to the selected state transition is selected as the estimated input information for that t. The above process is performed for each t=1, 2, . . . , T to generate a new estimate I 1,p T for each of the iteration p. [0077] Initially, the controller 202 places an estimate of the PDM P(X,Y) and π in the memory 204 that corresponds to the HMM for the channel 106 and/or the transmitter 102 . The PDM P(X,Y) may be obtained via well known training processes, for example. [0078] When ready, the controller 202 receives the received input information sequence Y 1 T and places them in the memory 204 and selects an initial estimate of I 1,0 T (or X 1,0 T ). The controller 202 coordinates the above-described iterative process until a new estimate I 1,1 T (or X 1,1 T ) is obtained. Then, the controller 202 compares I 1,0 T with I 1,1 T to determine if the compare result is below the compare threshold value (e.g., matching a predetermined number of elements or symbols of the information sequence). The compare threshold may be set to 0, in which case I 1,0 T must be identical with I 1,1 T . If an acceptable compare result is reached, I 1,1 T is output as the decoded output. Otherwise, the controller 202 iterates the above-described process again and compares the estimated I 1,p T with I 1,p−1 T until an acceptable result is reached and I 1,p T is output as the decoded output. [0079] [0079]FIG. 8 shows a flowchart of the above-described process. In step 1000 , the controller 202 receives Y 1 T via the input/output device 212 and places Y 1 T in the memory 204 and goes to step 1002 . In step 1002 , the controller 202 selects an initial estimate for I 1,0 T and goes to step 1004 . In step 1004 , the controller 202 determines a new state sequence and a next estimated I 1,1 T (I 1,p T , where p=1) (via the forward, backward and maximal length processors 206 , 208 and 210 ) and goes to step 1006 . In step 1006 , the controller 202 compares I 1,0 T with I 1,1 T . If the compare result is within the predetermined threshold, then the controller 202 goes to step 1008 ; otherwise, the controller 202 returns to step 1004 . In step 1008 , the controller 202 outputs I 1,p T where p is the index of the last iteration and goes to step 1010 and ends the process. [0080] [0080]FIG. 9 shows a flowchart that expands step 1004 in greater detail. In step 2000 , the controller 202 instructs the forward processor 206 to generate α i as shown in equation 8, and goes to step 2002 . In step 2002 , the controller 202 sets the parameter t=T and goes to step 2004 . In step 2004 , the controller 202 instructs the backward processor 208 to generate β j and the maximal length processor 210 to determine next set of survivors based on equation 18 and time t+1 survivors and goes to step 2006 . [0081] In step 2006 , the controller 202 decrements t and goes to step 2008 . In step 2008 , the controller 202 determines whether t is equal to 0. If t is equal to 0, the controller 202 goes to step 2010 ; otherwise, the controller 202 returns to step 2004 . In step 2010 , the controller 202 outputs the new estimated I 1 T and goes to step 2012 and returns to step 1006 of FIG. 5. [0082] A specific example of the iterative process for convolutional encoders is enclosed in the appendix. [0083] While this invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, preferred embodiments of the invention as set forth herein are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention. [0084] For example, a channel may be modeled as P c (Y|X)=P c B c (Y|X) where P c is a channel state transition probability matrix and B c (Y|X) is a diagonal matrix of state output probabilities. For example, based on the Gilbert-Elliott model B c  ( X  X ) = [ 1 - b 1 0 0 1 - b 2 ]     and     B c  ( X _  X ) = [ b 1 0 0 b 2 ] , [0085] where {overscore (X)} is the complement of X. For this case, m(I t ) may be simplified as m  ( I t ) = ∑ i = 1 n c     γ t , i  ( I 1 , p T )  b j  ( Y t | X t ) , t = 1 , 2 , …    , T , and [0086] and γ t,i (I 1,p T )=α i (Y 1 t |I 1,p t )β i (Y t+1 T |I t+1,p T ), where b j (Y t |X t ) are the elements of B c .

This invention provides an iterative process to maximum a posteriori (MAP) decoding. The iterative process uses an auxiliary function which is defined in terms of a complete data probability distribution. The auxiliary function is derived based on an expectation maximization (EM) algorithm. For a special case of trellis coded modulators, the auxiliary function may be iteratively evaluated by a combination of forward-backward and Viterbi algorithms. The iterative process converges monotonically and thus improves the performance of any decoding algorithm. The MAP decoding minimizes a probability of error. A direct approach to achieve this minimization results in complexity which grows exponentially with T, where T is the size of the input. The iterative process avoids this complexity by converging on the MAP solution through repeated maximization of the auxiliary function.

This is a continuation of application Ser. No. 08/357,092 filed Dec. 15, 1994, which is a continuation of application Ser. No. 08/185,167 filed Jan. 24, 1994, which is a continuation of application Ser. No. 07/786,606 filed Nov. 1, 1991, all now abandoned. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an autofocus camera in which focus is detected by either horizontal or vertical photoelectric conversion elements which are given priority. 2. Related Background Art A known example of such autofocus cameras is disclosed in Japanese Patent Application Laid-open No. 62-95511. This autofocus camera is described below with reference to FIG. 1. In FIG. 1, the subject light passed through a photographic lens 1 is passed through a cross-shaped opening 2a of a field mask 2 disposed at art expected focal plane of the photographic lens 1 and then through a capacitor lens 3 and four re-projecting lenses 4 to reach an image sensor 5. Two horizontal line image sensors (photoelectric conversion elements) 5a, 5b which are extended in the horizontal direction of a camera, and two vertical line image sensors (photoelectric conversion elements) 5c, 5d which are extended in the vertical direction of the camera are disposed on the image sensor 5. The light passed through the horizontal portion of the field mask opening 2a is received by the line image sensors 5a, 5b through the corresponding reprojecting lenses 4, and the light passed through the vertical portion of the opening 2a is received by the line image sensors 5c, 5d through the corresponding reprojecting lenses 4. The horizontal portion of the opening 2a corresponds to a horizontal detecting region 61 which is horizontally extended on the photographing image plane 60 shown in FIG. 2, and the vertical portion of the opening 2a corresponds to a vertical detecting region 62 which is vertically extended. Thus, the subject light from the horizontal detecting region 61 is received by the horizontal line image sensors 5a, 5b, and the subject light from the vertical detecting region 62 is received by the vertical line image sensors 5c, 5d. Each of the line image sensors 5a, 5b, 5c, 5d photoelectrically converts the subject light and provides an input signal to a focus detecting circuit (not shown). The focus detecting circuit calculates defocusing amount and direction from the input signal in order to drive the photographic lens 1 to the focusing position. The photographic lens 1 is focused on the basis of the defocusing amount and direction. The advantages of the above arrangement comprising the horizontal and vertical line image sensors are described below. In such a focus detection system, when a subject is parallel with the direction in which two line image sensors, i.e., a detecting region in the photographing image plane, are extended, since the output of the two line image sensors is flat without contrast, the defocusing amount and direction cannot be calculated, and the focus cannot be thus detected. The line image sensors are thus disposed in both the horizontal and vertical directions so that priority is given to the line image sensors in one (for example, the horizontal direction) of the two directions for detecting focus on the basis of the output thereof, and when the focus cannot be detected, the focus is detected on the basis of the output from the line image sensors in the other direction (vertical direction). This permits the focus to be surely detected regardless of the direction in which the subject is extended. In such conventional autofocus cameras, since the line image sensors given priority are fixed, the direction of the sensors given priority, i.e., the direction of the detecting region given priority, with respect to the subject when the camera is in the horizontal attitude is different from that in the vertical attitude. For example, when priority is given to the horizontal line image sensors (horizontal detecting region 61), the detecting region 61 given priority is extended in the horizontal direction of the subject when the camera is in the horizontal attitude, while the detecting region 61 is extended in the vertical direction of the subject when the camera is in the vertical attitude. It will be appreciated, of course, that when focus cannot be detected by using the line image sensors given priority, the time for focusing becomes longer. Thus, when the direction of the detecting region given priority with respect to the subject changes with changes in the attitude of the camera, as described above, there is the problem that the time for focusing the photographic lens when the subject is in the vertical attitude is different from that when the same subject is in the horizontal attitude. SUMMARY OF THE INVENTION In accordance with a first of its principal aspects, the present invention provides an autofocus camera which conducts a focus detection operation with one of differently directed sets of photoelectric conversion elements which is given priority according to the detected attitude of the camera. If focusing cannot be effected using the elements given priority, a focus detection operation is automatically conducted with the other elements. In accordance with another of its principal aspects, the invention provides an auto focus camera in which each of differently directed first and second photoelectric conversion means includes a plurality of light-receiving elements. The camera has a first mode of operation in which focus detecting operations are conducted which collectively utilize outputs of all of the light-receiving elements when a first camera attitude is detected, and a second mode of operation in which focus detecting operations are conducted which collectively disregard the output of at least one such element when a second camera attitude is detected. The various features and advantages of the present invention will be more fully appreciated from the following description of the embodiments illustrated in the accompanying drawings. Although the present invention is described with reference to embodiments shown in the drawings, the invention is not limited to these embodiments. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a focus detecting optical system; FIG. 2 is a drawing showing focus detecting regions; FIGS. 3 to 5 show an embodiment of the present invention, in which FIG. 3 is a block diagram showing the control system of an autofocus camera according to the invention, FIG. 4 is a drawing showing the relation of the attitude of a camera to the state of a mercury switch and the direction of a photographing image plane, and FIG. 5 is a flow chart showing the processing procedure; FIGS. 6 to 9 show another embodiment of the invention, in which: FIG. 6 is a drawing showing the arrangement of line image sensors; FIG. 7 is a drawing showing focus detecting regions on a photographing image plane; FIG. 8 is a flow chart showing the processing procedure; and FIG. 9 is a drawing showing focus detecting regions on a photographing image plane when a person is photographed by a camera in the vertical attitude. DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to an autofocus camera having the focus detecting optical system shown in FIG. 1 is described below with reference to FIGS. 3 to 5. FIG. 3 is a block diagram showing the control system of an autofocus camera according to the present invention. A horizontal focus detecting circuit 22 and a vertical focus detecting circuit 23 are connected to a control circuit 21. The horizontal focus detecting circuit 22 performs a known focus detecting operation for calculating the defocusing amount and defocusing direction using the photoelectric conversion output from the horizontal line image sensors 5a, 5b shown in FIG. 1, both of which receives the subject light from the horizontal detecting regions 61 on the photographing image plane 60, so as to focus the photographing lens 1 on the subject. Similarly, the vertical focus detecting circuit 23 performs the focus detecting operation for calculating the defocusing amount and defocusing direction using the output from the vertical line image sensors 5c, 5d, both of which receive the subject light from the vertical detecting region 62 on the photographing image plane 60. In this embodiment, the line image sensors corresponding to the focus detecting region extended in the horizontal direction of the subject are given priority for detecting the focus because the subject is generally frequently extended in the vertical direction rather than in the horizontal direction. A indicating circuit 24, a lens driving circuit 25 and two mercury switches SW1, SW2 are also connected to the control circuit 21. A focusing motor 26 is connected to the lens driving circuit 25 so as to be driven in response to the command from the control circuit for focusing the photographing lens 1. The indicating circuit 24 indicates the impossibility of focusing by using a display (not shown) provided, for example, in a finder in response to the command from the control circuit 21. The mercury switches SW1, SW2 are arranged substantially in the form of an invented V when the camera is in the normal horizontal attitude (in which the upper side of the camera body faces upward), as shown by (1) in FIG. 4. The on/off state of each of the mercury switches SW1, SW2 is changed as the mercury is gravitationally moved according to the attitude of the camera, as shown in FIG. 4. Namely, when the camera is in the attitude (horizontal attitude) shown by (1) in FIG. 4, both switches SW1, SW2 are turned off, and when the camera is in the attitude (vertical attitude) shown by (2), the switch SW1 is turned on, while the switch SW2 is turned off. In the attitude (vertical attitude) shown by (3), the switch SW1 is turned off, while the switch SW2 is turned on. In the attitude (horizontal attitude) shown by (4), both switches SW1, SW2 are turned on. The procedure of the focusing control by the control circuit 21 is described below on the basis of the flow chart shown in FIG. 5. For example, when a release button (not shown) is half pushed, the program shown in FIG. 5 is started. In Step S1, the attitude of the camera is first detected from the states of the mercury switches SW1, SW2. If both switches SW1, SW2 are turned on or off, it is decided that the camera is in the horizontal attitude, i.e., the attitude shown by (1) or (4) in FIG. 4, and the flow moves to Step S2 in which the horizontal focus detecting circuit 22 is started. The horizontal focus detecting circuit 22 reads the output of the horizontal line image sensors 5a, 5b, determines the defocusing amount and defocusing direction of the photographic lens by a known focus detecting operation on the basis of the output of the horizontal line image sensors 5a, 5b and inputs the defocusing amount and direction to the control circuit 21. When the defocusing amount and defocusing direction cannot be calculated because horizontal contrast is absent in the subject, a signal indicating the impossibility of focusing is input to the control circuit 21. In Step S3, the control circuit 21 makes a decision on the basis of the output from the horizontal focus detecting circuit 22 whether or not the focus can be detected. If it is decided that the focus can be detected, in Step S4, a lens driving signal corresponding to the defocusing amount and direction is output to the lens driving circuit 25 so as to drive the photographic lens 1 toward the focusing position by using the motor 26. On the other hand, if it is decided in Step S3 that the focus cannot be detected, the flow moves to Step S5 in which the vertical focus detecting circuit 23 is started. The vertical focus detecting circuit 23 detects the focus on the basis of the output from the vertical line image sensors 5c, 5d and inputs the defocusing amount and direction or the signal indicating the impossibility of focusing to the control circuit 21 in the same way as that described above. In Step S6, the control circuit 21 makes a decision on the basis of the input signal whether or not the focus can be detected. If it is decided that the focus can be detected, the flow moves to Step S4, while if it is decided that the focus cannot be detected, the flow moves to Step S11. In Step S11, a display signal is sent to the indicating circuit 24 so that the impossibility of focusing is indicated by the display (not shown), On the other hand, in Step S1, if one of the two switches SW1, SW2 is turned on, and the other is turned off, it is decided that the camera is in the vertical attitude, i.e., the attitude shown by (2) or (3), and the flow moves to Step S7 in which the vertical focus detecting circuit 23 is started. In Step S8, a decision is made on the basis of the output from the vertical focus detecting circuit 23 whether or not the focus can be detected. If it is decided that the focus can be detected, in Step S4, the lens driving signal corresponding to the defocusing amount and direction, both of which are input from the vertical focus driving circuit 23, is output to the lens driving circuit 25 so as to drive the photographic lens 1 toward the focusing position by using the motor 26. If it is decided in Step S8 that the focus cannot be detected, the flow moves to Step S9 in which the horizontal focus detecting circuit 22 is started. In Step S10, a decision is made on the basis of the signal from the horizontal focus detecting circuit 22 as to whether or not the focus can be detected. If it is decided that the focus can be detected, the flow moves to Step S4, while if it is decided that the focus cannot be detected, the flow moves to Step S11. In detection of the focus according to the abovedescribed procedure, priority is given to the horizontal lime image sensors 5a, 5b when the camera is in the horizontal attitude, while priority is given to the vertical line image sensors 5c, 5d when the camera is in the vertical attitude. The shaded region in the photographing image plane 60 shown in FIG. 4 shows a detecting region corresponding to the line image sensors having priority. As shown in FIG. 4, the line image sensors given priority, i.e., the detecting region given priority, are constantly in the horizontal direction with respect to the subject regardless of the attitude of the camera. In the case of a vertical subject (ordinary case), the time required for focusing the photographic lens 1 can be minimized regardless of the attitude of the camera. In this embodiment, the horizontal line image sensors 5a, 5b comprise horizontal photoelectric conversion elements, the vertical line image sensors 5c, 5d comprise vertical photoelectric conversion elements, the control circuit 21 and the horizontal and vertical focus detecting circuits 22, 23 comprise focus detecting devices, the lens driving circuit 25 and the motor 26 comprise lens driving devices and the mercury switches SW1, SW2 comprise attitude detecting devices, respectively. FIGS. 6 to 9 show another embodiment of the invention. FIG. 6 shows the arrangement of line image sensors. As shown in the drawing, in this embodiment, a line image sensor 50 is divided into partial sensors 50a, 50b, 50c, 50d, 50e, 50f. The partial sensors 50a, 50b receive the subject light from the detecting region X1 in the photographing image plane 70 shown in FIG. 7. The partial sensors 50c, 50d receive the subject light from the detecting region X2, and the partial sensors 50e, 50f receive the subject light from the detecting region X3. The horizontal focus detecting circuit 22 calculates the defocusing amount and direction on the basis of the output from the partial sensors. The vertical focus detecting circuit 23 calculates the defocusing amount and direction on the basis of the output from the vertical line image sensors 5c, 5d, like the above-described embodiment. FIG. 8 shows a flow chart for focusing control in this embodiment. In Step S21, the attitude of the camera is detected according to the states of the mercury switches SW1, SW2 in the same way as the first embodiment. If the camera is in the horizontal attitude (shown by (1) or (4) in FIG. 4), the horizontal focus detecting circuit 22 is started so as to determine the defocusing amount and direction on the basis of the output from the central partial sensors 50c, 50d (corresponding to the detecting region X2). Namely, the detecting circuit 22 detects the focus. In Step S22, a decision is made on the basis of the output from the partial sensors 50c, 50d as to whether or not the focus can be detected. If it is decided that the focus cannot be detected, the focus is detected on the basis of the output from the vertical line image sensors 5c, 5d (corresponding to the detecting region Y). If it is decided in Step S23 that the focus cannot be detected, the impossibility of focusing is indicated in Step S24 in the same way as that described above. In the case of Yes in Step S22, the flow moves to Step S25. In the case of Yes in Step S23, the output from the image sensors 5c, 5d is handled as the output from the partial sensors 50c, 50d, and the flow moves to Step S25. In Step S25, the focus is detected on the basis of the output from the partial sensors 50a, 50b (corresponding to the detecting region X1), the partial sensors 50c, 50d (corresponding to the detecting region X2 or Y) and the partial sensors 50e, 50f (corresponding to the detecting region X3). The detection may be controlled by, for example, the method disclosed in Japanese Patent Application Laid-open No. 63-18314. The details of this control method are not described below because the method per se is not part of the present invention. The processing then goes to Step S27 in which the photographic lens 1 is focused on the basis of the results of focus detection performed in Step S25. On the other hand, if it is decided in Step S21 that the camera is in the vertical attitude, i.e., the attitude shown by (2) or (3) in FIG. 4, the focus is detected on the basis of the output from the vertical line image sensors 5c, 5d. If it is decided in Step S28 that the focus cannot be detected, the focus is detected on the basis of the output from the partial sensors 50c, 50d, and the flow moves to Step S29. If it is decided in Step S29 that the focus cannot be detected, the impossibility of focusing is indicated in Step S30, and the processing is finished. If it is decided in Step S29 that the focus can be detected, the output from the partial sensors 50c, 50d is handled as the output from the vertical line image sensors 5c, 5d in Step S31, and the flow then moves to Step S32. If it is decided in Step S28 that the focus can be detected, a decision is made in Step S33 as to whether or not the focus can be detected with the uppermost partial sensors. When the camera is in the attitude (2), the uppermost partial sensors are the partial sensors 50a, 50b (corresponding to the uppermost detecting region X1). When the camera is in the attitude (3), the uppermost partial sensors are the partial sensors 50e, 50f (corresponding to the uppermost detecting region X3). In the case of No in Step S33, the focus detecting output (defocusing amount and direction) based on the output from the vertical line image sensors 5c, 5d is used in Step S34. The flow then moves to Step S27 for focusing on the basis of that output. In the case of Yes in Step S33, the flow moves to Step S32 for determining the difference ΔD (ΔD=|Dy-Dup|) between the focus detecting output Dy based on the output from the vertical line image sensors 5c, 5d and the focus detecting output Dup from the uppermost partial sensors. If the difference ΔD is less than a predetermined value DO, the focus detecting output based on the output from the uppermost partial sensors is employed in Step S35. If the difference ΔD is over the predetermined value DO, the focus detecting output based on the output from the vertical line image sensors 5c, 5d (in this case, extended in the horizontal direction of the subject) is employed in Step S36, and the flow then moves to Step S27. In the detection of the focus according to the above-described procedure, priority is given to the horizontal line image sensor 50 when the camera is in the horizontal attitude, and priority is given to the vertical line image sensors 5c, 5d when the camera is in the vertical attitude in the same way as in the first embodiment. The same effects as those obtained in the first embodiment can thus be obtained. Particularly, in this embodiment, when the camera is in the vertical attitude, i.e., the attitude in which the horizontal focus detecting regions X1, X2, X3 are vertically extended, the vertical line image sensors 5c, 5d and the uppermost partial sensors have priority for detecting the focus. When a person is photographed, for example, by the camera in the vertical attitude, as shown in FIG. 9, the uppermost detecting region (X1 in the case shown in FIG. 9) of the horizontal detecting regions X1, X2, X3 is frequently placed at the position of the face of the subject. The photographic lens can thus be focused on the face of the subject by the uppermost partial sensors given priority. However, when two persons form a line, the uppermost detecting region is placed in the background, and there is thus the possibility of producing a so-called middle blank. The difference ΔD between the focus detecting output Dup based of the output from the uppermost partial sensors and the focus detecting output Dy based on the output from the vertical line image sensors 5c, 5d is thus determined. When the difference ΔD is less than the predetermined value DO, it is decided that the main subject is placed in the uppermost detecting region, and the focus detecting output based on the output from the uppermost partial sensors is employed. When the difference ΔD is greater than the predetermined value DO, it is decided that the main subject is not placed in the uppermost detecting region, and the focus detecting output based on the output from the vertical line image sensors 5c, 5d is employed for driving the lens. It is therefore possible to surely focus on the main subject. Although, in this embodiment, the horizontal line image sensor is divided into a plurality portions, the vertical line image sensor may be divided. Also, while the above embodiments concern the case in which the focus is detected on the basis of the subject light passed through the photographic lens, the focus may be detected by receiving the subject light without passing through the photographic lens. In addition, the horizontal and vertical focus detecting regions need not be arranged in a cross form, but may be separated from each other. Further, although the above embodiments concern the case where priority is given to the line image sensors corresponding to the focus detecting region extended in the horizontal direction of the subject, priority may be given to the line image sensors corresponding to the focus detecting region extended in the vertical direction of the subject. Of course, attitude detecting devices for the camera are not limited to the mercury switches SW1, SW2. In the present invention, in a camera having horizontal and vertical focus detecting photoelectric conversion elements, the direction of the photoelectric conversion elements given priority, i.e., the detecting region given priority, with respect to the subject remains unchanged regardless of the attitude of the camera. It is thus possible to effect focusing of the photographic lens without undue delay even if the attitude with respect to the subject is changed.

An autofocus camera conducts a focus detection operation with one of differently directed sets of photoelectric conversion elements which is given priority according to the detected attitude of the camera. If focusing cannot be effected using the elements given priority, a focus detection operation is automatically conducted with the other elements. Also provided is a camera having a first mode of operation in which focusing detecting operations are conducted which collectively utilize outputs of all of the elements of differently directed sets of photoelectric conversion elements when a first camera attitude is detected, and a second mode of operation in which focusing detecting operations are conducted which collectively disregard the output of at least one conversion element when a second camera attitude is detected.

CROSS-REFERENCE TO RELATED APPLICATIONS The present application is a national phase entry under 35 U.S.C. §371 of International Application No. PCT/CN2014/090535 filed Nov. 7, 2014 which claims priority from Chinese application 201410029070.X filed Jan. 22, 2014, all of which are incorporated herein by reference. FIELD OF THE INVENTION The present invention relates to a sensing control system. More specifically, it is a sensing control system for an electric toy. BACKGROUND Regarding the currently available electric toys, one type of them is controlled by a mechanical switch or button. Through turning on a mechanical switch or button provided on the body of an electric toy, the toy accordingly makes certain corresponding actions, which is driven by electric power. Nevertheless, the action of this type of electric toys cannot be controlled by a user. That is to say, after the mechanical switch or button being turned on, the electric driving device of the toy can only operate based on the parameters set in the production; in other words, these parameters are fixed and thus cannot be changed or modified. As a result, the action of the toy cannot be changed. In addition, there is another type of electric toy that can be controlled with a remote control. Through the remote control, the electric toy's action can be controlled. That is to say, by virtue of a remote control, a user can change or modify the action parameters of the toy, which leads to corresponding changes of the toy's action. However, this type of toy is significantly dependent on its remote control. In the case that its remote control is damaged, the toy would no longer function. Further, it could be a challenge for a child at very young age to control an electric toy's action through a remote control. Moreover, there is another type of electric toys that can be control through its sensing function, such as the non-contact sensing, for example, infrared sensing, and the contact sensing, for example, slot card sensing. Nevertheless, as for the currently available sensing controlled operation, their functions are actually equivalent to that of the above mentioned switch or button. That is to say, upon receiving a sensing signal, the toy can only make one corresponding action. As a result, this type of toy is not able to accomplish action changes through those sensing controls as well. SUMMARY OF DISCLOSURE To address the technical problem in the existing technology described above, one aim of the present invention is to provide a sensing control system for an electric toy, which is able to control the toy's action change by virtue of the number of frequency or sensing signals. In order to achieve the foregoing aim, the present invention employs the technical solution as follows: a sensing control system for an electric toy, characterized by comprising: a signal detection module for receiving an external sensing and then generating a sensing signal; a calculation and control module for receiving the sensing signal and counting a number of the sensing signal and then sending out different control signals corresponding to different numbers of the sensing signals; and an electric driving module for receiving the control signal, and then sending a driving signal to the electric toy, so as to control the electric toy to work. In which, the signal detection module comprises a non-contact sensing circuit, the non-contact sensing circuit is provided with a sensing receiver, the sensing receiver tracks and senses an action of a user in a real time manner, with respect to each action made by the user, the sensing receiver outputs one sensing signal and sends out the sensing signal to the calculation and control module. In the present invention, the non-contact sensing circuit is selected from the group consisting of photo-sensitive sensing circuit, magnetic sensing circuit, thermal sensing circuit and sound sensing circuit. In addition, in order to count the number or frequency of the sensing event, the calculation and control module comprises a control chip, the control chip is able to record the number of sensing signal sent out from the signal detection module in a continuous time period, and according to the recorded number of sensing signal to further send out a control signal to the electric driving module, wherein the control signal is corresponding to the recorded number of sensing signal. Moreover, in order to identify the number of sensing and accordingly send out a corresponding control signal, the control chip has been stored with a plurality sets of control signals, wherein each set of control signal is corresponding to a range of the number, in the case that the above mentioned recorded number is not within any one of the ranges of the number, no signal is sent out; while in the case that the recorded number is within one of the ranges of the number, send out the control signal that is corresponding to the range of the number within which the recorded number is. The sensing control system of the present invention can be applied in a wide variety of different electric toys. In this regard, the disclosed electric driving module can be selected from the group consisting of motor driving module, light driving module, sound driving module, electromagnet driving module and a combination of two or more of the foregoing. More specifically, in the case the electric driving module is a motor driving module comprising a motor and the calculation and control module is provided with a single chip microcomputer (SCM), the single chip microcomputer (SCM) would be stored with the control signals as follows: when a range of the number is N 1 , the motor runs at a speed of S 1 for T 1 seconds; when a range of the number is N 2 , the motor runs at a speed of S 2 for T 2 seconds; and when a range of the number is N 3 , the motor runs at a speed of S 3 for T 3 seconds; and so forth, when a range of the number is N m , the motor runs at a speed of S m for T m seconds; when a range of the number is N 2 , in which N 1 <N 2 <N 3 <N m , S 1 <S 2 <S 3 <S m , and T 1 <T 2 <T 3 <T m . On the other hand, the signal detection module is a photo-sensitive sensing module that comprises a phototransistor, the phototransistor is arranged on an upper surface of the electric toy, when a user waves his or her hand above the electric toy, the phototransistor receives a sensing and accordingly sends out a sensing signal to the calculation and control module, in the case that the user waves his or her hand for X times in a continuous time period and with a time interval between two consecutive waving actions no longer than 1 second, 1 second after the termination of the waving action by the user, the single chip microcomputer (SCM) counts the number of the received sensing signal and reaches a counting number X, and then respectively compares this number X with N 1 , N 2 , N 3 . . . N m , if X is smaller than N 1 , no signal is sent out, if X is within one of N 2 , N 3 . . . N m , the control signal corresponding to the range of the number within which X is sent out to the electric driving module, which further drives the motor to run according to the specified running speed and the specified running time corresponding to that control signal. Furthermore, the signal detection model of the present invention may comprise at least two non-contact sensing circuits, with each of the non-contact sensing circuits having been provided with a sensing receiver, the sensing receiver tracks and senses an action of a user in a real time manner, with respect to each action made by the user, the sensing receiver outputs one sensing signal and sends out this sensing signal to the calculation and control module, and the calculation and control module then sends out a corresponding control signal based on a determination of the combination of received a plurality of sensing signals. On the other hand, the non-contact sensing circuit is selected from the group consisting of photo-sensitive sensing circuit, magnetic sensing circuit, thermal sensing circuit, sound sensing circuit and a combination of two or more of the foregoing. In the present invention, the sensing control system has been provided with a calculation and control module. Through the calculation and control module, it is able to count the number of sensing events received by the signal detection module. Subsequently, based on the result from a comparison between the number of sensing events obtained from the foregoing counting and the data previously stored in the calculation and control module, a control signal that corresponds to the obtained number of sensing events is further sent out to an electric driving module, and eventually, the electric driving module sends out a driving signal to control the electric toy to act. As a result, based on different number of sensing events, the electric toy is capable of performing different actions or allowing one action to have changes in its speed. In this way, the present invention is able to make an electric toy that has been equipped with the sensing control system disclosed in the present invention to go beyond the limitation of a remote control, and thus becomes suitable as a toy for children of different ages. In addition, it makes a toy gain the advantages of becoming more user friendly, more interactive, more interesting, and thus would become many children's favorite. On the other hand, the sending control system may be provided with at least two non-contact sensing circuits, and each of the non-contact sensing circuits is provided with a sensing receiver. As a result, for each action or movement made by a user, the respective sensing receiver would output a corresponding sensing signal, and send out the foregoing sensing signal to the calculation and control module; and the calculation and control module accordingly sends out a corresponding control signal based on a determination of the received combination of a plurality of sensing signals. In this way, a user can have more different ways to play the electric toy. For example, a user can control the electric toy to move forward and backward, to turn to its left side or right side. In addition, by virtue of different signal combinations, the electric toy can gain more functions, such as prevention of trample and many other new functions, and make the operation become more flexible and easier to control. In addition, as disclosed previously, the non-contact sensing circuits of a toy may be selected from the group consisting of photo-sensitive sensing circuit, magnetic sensing circuit, thermal sensing circuit, sound sensing circuit and a combination of two or more of the foregoing. In this way, different sensing circuits may be employed together to control different functions of the same electric toy. In this way, the operability and enjoyability of the electric toy has been effectively improved. The present invention will be further described in combination with the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of the circuit of an embodiment of the present invention. FIG. 2 is a schematic view of the circuit of another embodiment of the present invention. DETAILED DESCRIPTION OF THE DRAWINGS As shown in FIG. 1 and FIG. 2 , the present invention is a sensing control system for an electric toy, comprising: a signal detection module for receiving an external sensing and then generating a sensing signal; a calculation and control module for receiving the sensing signal and counting a number of the sensing signal, and then sending out different control signals corresponding to different numbers of the sensing signals; as well as an electric driving module for receiving the control signal and then sending a driving signal to the electric toy, so as to control the electric toy to work. In addition, through the calculation and control module, it is able to count the number of sensing signals received by the signal detection module. Subsequently, based on the result from a comparison between the number of sensing events obtained from the foregoing counting and the data previously stored in the calculation and control module, a control signal that is corresponding to the obtained number of sensing events is further sent out to the electric driving module, and eventually, the electric driving module sends out a driving signal to control the electric toy. As a result, based on different number of sensing events, the electric toy is capable of performing different actions or allowing one action to have changes in its speed. In this way, the present invention is able to make an electric toy that has been equipped with the sensing control system disclosed in the present invention go beyond the limitation of a remote control, and thus becomes suitable as a toy for children of different ages. In addition, it makes a toy gain advantages of becoming more user friendly, more interactive, more interesting, and thus would become many children's favorite. DETAILED DESCRIPTION Embodiment 1 As shown in FIG. 1 , in this embodiment, the signal detection module comprises a non-contact sensing circuit, and the non-contact sensing circuit is a photo-sensitive sensing circuit, which corresponds to a sensing receiver that is a phototransistor. In addition, in this embodiment, it is also provided with an emission source. The phototransistor and the emission source have been arranged on the top of an electric toy car, so as to allow them to be able to track and sense the hand waving action of a user in a real time manner. Accordingly, when a user waves his or her hand once above the electric toy car, the sensing receiver correspondingly outputs a sensing signal, and then sends out the sensing signal to the calculation and control module. In addition, the calculation and control module is provided with a single chip microcomputer (SCM). The SN8P2511-SOP8 single chip microcomputer (SCM) has been employed in the present invention. This SCM is able to record the number of the sensing signal sent out from the above mentioned photo-sensitive sensing receiver in a continuous time period, as well as according to the recorded number of sensing signal to send out a control signal that is corresponding to the recorded number of sensing signal to the electric driving module. Moreover, the SCM has been stored of five sets of control signals, wherein each set of control signal is corresponding to a respective range of number. In the case that the recorded number is not within any one of the ranges of number, no signal is sent out; while in the case that the recorded number is within one of the ranges of number, send out the control signal that is corresponding to the range of number within which the recorded number of sensing signal is. Furthermore, the calculation and control module is also provided with an LED light. The LED light is able to flash according to the speed of a user's hand waving action. In this embodiment, the electric driving module is an electric driving module containing a motor, which has been arranged in the electric toy car. The control signal sent out from the SCM is used to control the motor's operation. The specific control signals stored in the single chip microcomputer (SCM) in this embodiment are as follows: {circumflex over (1)} waving hand 4 to 6 times, 1 second after completion of the foregoing waving action the electric car moving forward for 1 second, and the moving speed being 30% of a full running speed of the motor; {circumflex over (2)} waving hand 7 to 9 times, 1 second after completion of the foregoing waving action the electric car moving forward for 2 seconds, and the moving speed being 45% of a full running speed of the motor; {circumflex over (3)} waving hand 10 to 14 times, 1 second after completion of the foregoing waving action the electric car moving forward for 4 seconds, and the moving speed being 60% of a full running speed of the motor; {circumflex over (4)} waving hand 15 to 20 times, second after completion of the foregoing waving action the electric car moving forward for 8 seconds, and the moving speed being 80% of a full running speed of the motor; and {circumflex over (5)} waving hand more than 21 times, second after completion of the foregoing waving action the electric car moving forward for 12 seconds, and the moving speed being 100% of a full running speed of the motor. In the case that the sensing control system described in this embodiment is used in an electric toy car, the operation procedure accordingly is as follows: press the power button, the system starts to work and the electric toy car is in a standby state at this moment, when a user waves his or her hand above the electric toy car and the waving action meets the requirement that the time interval between two consecutive hand waving actions is no more than 1 second, if the number of hand waving action is no more than 3 times within a time period of 4 seconds, the electric toy car does not respond and thus remains in the standby state to wait for future sensing; if the number of hand waving action is more than 4 times within a continuous time period, according to the respective control signal from the SCM, the user is able to control the electric toy car to move. For example, in the case that the user waves his or her hand 5 times, 1 second after completion of the foregoing waving action, the electric car moves forward for 1 second at the moving speed that is 30% of a full running speed of the motor; in the case that the user waves his or her hand 10 times, 1 second after completion of the foregoing waving action, the electric car moves forward for 4 seconds at the moving speed that is 60% of a full running speed of the motor; and in another case that the user waves his or her hand 25 times, 1 second after completion of the foregoing waving action, the electric car moves forward for seconds at the moving speed that is 100% of a full running speed of the motor. Further, after finishing one moving forward action, the electric toy car returns to the standby state, and in the case that a hand waving action is sensed within the next 5 minutes, the electric toy car runs again according to the respective number of hand waving actions. On the other hand, if no any hand waving action has been sensed within the next 5 minutes, the electric toy car then goes into an off state. In this case, a user needs to press the power button again to turn on the electric car back into a play state. Moreover, if a user needs to shut down the toy car manually, the user may achieve it by pressing the power button for 2 to 3 seconds. Embodiment 2 As shown in FIG. 2 , in this embodiment, the signal detection module comprises three non-contact sensing circuits, and each of the three non-contact sensing circuits has been provided of a sensing receiver, wherein two of the three non-contact sensing circuits are photo-sensitive sensing circuits, with their corresponding sensing receivers as phototransistors; and the third non-contact sensing circuit is a magnetic sensing circuit, with its corresponding sensing receiver as a magnetic sensing circuit. In this embodiment, the two phototransistors are able to track and sense the hand waving action from a user in a real time manner. On the other hand, the magnetic sensing element can only sense when a user is making a hand waving action with a magnetic article in his or her hand. When a user waves his or her hand once, the sensing receiver that is capable of sensing will correspondingly output a sensing signal, and then send out the sensing signal to the calculation and control module. The calculation and control module controls the moving direction of the electric toy by means of determining the specific sequence of the generated sensing signals. The calculation and control module has been provided with an SN8P2511-SOP14 single chip microcomputer (SCM). The single chip microcomputer (SCM) is able to record the respective number of sensing signals sent out from the above mentioned three sensing receivers in a continuous time period, as well as according to the recorded number to send out a control signal that is corresponding to the recorded number to the electric driving module. Similarly, the SCM has been stored with multiple sets of control signals, in which each set of control signal is corresponding to a respective range of number. In the case that the recorded number is not within any one of the ranges of the number, no signal is sent out; while in the case that the recorded number is within one of the ranges of the number, send out the control signal that corresponds to the range of the number within which the recorded number is. And similarly, the calculation and control module is also provided with an LED light. The LED light is able to flash according to the speed of a user's hand waving action. In this embodiment, the electric driving module is an electric driving module containing a motor, which has been arranged in the electric toy car. The control signal sent out from the SCM is used to control the motor's operation. In this embodiment, the above mentioned two phototransistors are disposed on the top of an electric toy car and in a front to rear arrangement. The magnetic element is disposed on one side of the two phototransistors. When a user makes a hand waving action from rear side toward front side of the electric toy car with an empty hand, the phototransistor located on the rear side of the toy car senses the waving action first and accordingly sends out a sensing signal, and then the phototransistor located on the front side of the toy car senses the waving action next and accordingly sends out a sensing signal as well. As for the magnetic element, it is not able to sense the waving action with an empty hand and accordingly does not send out any magnetic sensing signal in this situation. The SCM first determines the sequence in which the two sensing signals have been generated as well as the number of the waving actions made by the user in a continuous time period, and accordingly, controls the electric toy car to move forward at a speed corresponding to the number of sensed waving actions. In the case when a user makes a hand waving action from front side toward rear side of the electric toy car with an empty hand, the phototransistor located on the front side of the toy car senses the waving action first and accordingly sends out a sensing signal, and then the phototransistor located on the rear side of the toy car senses the waving action next and accordingly sends out a sensing signal as well. As for the magnetic element, it is not able to sense the waving action with an empty hand and accordingly does not send out any magnetic sensing signal. The SCM first determines the sequence in which the two sensing signals have been generated as well as the number of the waving actions made by the user in a continuous time period, and accordingly, controls the electric toy car to move backward at a speed corresponding to the number of sensed waving actions. In another case, when a user makes a hand waving action above the electric toy car with a magnetic article in hand, the two phototransistors sensing the hand waving action sequentially and accordingly send out respective sensing signals, in addition, because of the magnetic article, the magnetic sensing element will send out a magnetic signal in this case. The SCM first determines the sequence in which the two sensing signals have been generated as well as the number of the waving actions made by the user in a continuous time period, and accordingly, controls the electric toy car to move forward or backward at a speed corresponding to the number of hand waving actions. And at the same time, the SCM receives the magnetic sensing signal sent form the magnetic sensing circuit and accordingly sends out a corresponding instruction to control certain other functions of the electric toy car. More specifically, in this embodiment, when the SCM receives the magnetic sensing signal, it will further control to increase running speed of the motor in the electric toy car. That is to say, with the same number of hand waving actions, when a user makes the hand waving actions with a magnetic article in the user' hand, the electric toy car would move faster than that when the user makes hand waving actions with an empty hand. Although the present invention has been described in reference to the specific embodiments described above, the description of embodiments does not intend to limit the present invention. On the basis of the description of the present invention, a person of ordinary skill in the art is able to anticipate other changes for the disclosed embodiments. Therefore, these changes are within the scope defined by the claims of the present application.

The present invention provides a sensing control system for an electric toy, characterized in that it comprises a signal detection module for receiving an external sensing and then generating a sensing signal; a calculation and control module for receiving the sensing signal and counting a number of the sensing signal, and then sending out different control signals corresponding to different numbers of the sensing signals; and an electric driving module for receiving the control signal and then sending a driving signal to the electric toy, so as to control the electric toy to work. Therefore, according to different numbers of sensing signals, the electric toy is able to perform different actions or speed changes of the same action. In this way, the toy equipped with the sensing control system of the present invention can go beyond the limitation of a remote control, and thus becomes suitable as a toy for children of different ages. In addition, it makes a toy gain advantages of becoming more user friendly, more interactive, more interesting, and thus would become many children's favorite.

STATEMENT OF GOVERNMENT RIGHTS [0001] This invention was made with Government support under Contract No.: N00014-12-C-0472 awarded by the Office of Navy Research. The Government has certain rights in this invention. BACKGROUND [0002] The present application relates to reactive material stacks, and more particularly to reactive material stacks with tunable ignition temperatures. [0003] Reactive materials are a class of materials which can react to generate heat through a spontaneously exothermic reaction without producing gaseous products or generating a large pressure wave. Reactive materials are thus useful in a wide variety of applications requiring generation of intense, controlled amount of heat, including bonding, melting and microelectronics where the release of energy needed can be triggered by external ignition with, or without, a source of oxygen. For certain applications, it may be important that the energy stored in the reactive materials is not released until needed. For example and when employed as erasure elements to induce phase transformation of phase change materials of phase change memory (PCM) cells in an integrated circuit chip, the reactive materials need to be benign during the back end-of-line fabrication process (which typically requires annealing the chip at a temperature up to 400° C.) and normal chip operations, but can be ignited quickly when a triggering event occurs, e.g., when the chip is compromised (e.g., lost or stolen) and a possibility of a security breach could occur. SUMMARY [0004] The present application provides reactive material stacks with tunable ignition temperatures. By separating alternating layers of reactive materials from one another with a barrier layer, the interdiffusion of metal elements of the reactive materials is prevented. The reactive material stacks thus remain unreacted until a high energy threshold is reached. [0005] In one aspect of the present application, a reactive material stack is provided. The reactive material stack includes alternating layers of a first reactive material and a second reactive material and a barrier layer located between the layers of the first reactive material and the second reactive material, wherein the barrier layer comprises a transition metal, an oxide thereof, a nitride thereof, aluminum oxide (Al x O y ) or a combination thereof. [0006] In another aspect of the present application, a method of forming a reactive material stack is provided. [0007] In one embodiment, the method includes forming a layer of a first reactive material over a substrate, forming a barrier layer over the layer of the first reactive material, forming a layer of a second reactive material over the barrier layer, forming another barrier layer over the layer of the second reactive material and repeating the forming of the layer of the first reactive material, the forming of the barrier layer, the forming of the second reactive material, and the forming of the another barrier layer to provide a desired thickness for the reactive material stack. [0008] In another embodiment, the method includes forming a layer of a first reactive material over a substrate, forming a layer of a second reactive material over the layer of the first reactive material, forming a barrier layer over the layer of the second reactive material, and repeating the forming of the layer of the first reactive material, the forming of the second reactive material, and the forming of the barrier layer to provide a desired thickness for the reactive material stack. BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS [0009] FIG. 1 is a cross-sectional view of an exemplary reactive material stack that can be employed in an embodiment of the present application. [0010] FIG. 2 is a cross-sectional view illustrating a barrier layer stack that can be employed in the exemplary reactive material stack of the present application. [0011] FIG. 3 is a cross-sectional view of another exemplary reactive material stack that can be employed in another embodiment of the present application. [0012] FIG. 4A shows a graph of sheet resistance versus temperature for a conventional reactive material stack including a bilayer of Al/Ni formed over a SiO 2 coated substrate. [0013] FIG. 4B shows a X-ray diffraction (XRD) profile of the conventional reactive material stack. [0014] FIG. 5A shows a graph of sheet resistance versus temperature for a first exemplary reactive material stack that includes a single barrier layer sandwiched between an Al layer and a Ni layer according to a first example of the present application. [0015] FIG. 5B shows a XRD profile of the first exemplary reactive material stack. [0016] FIG. 6A shows a graph of sheet resistance versus temperature for a second exemplary reactive material stack that includes a barrier layer stack sandwiched between an Al layer and a Ni layer according to a second example of the present application. [0017] FIG. 6B shows a XRD profile of the second exemplary reactive material stack. [0018] FIG. 6C shows a graph of sheet resistance versus heating time for the second exemplary reactive material stack. [0019] FIG. 7 is a bar graph showing effects of barriers layers on ignition temperatures of a Ni—Al reactive material pair. DETAILED DESCRIPTION [0020] The present application will now be described in greater detail by referring to the following discussion and drawings that accompany the present application. It is noted that the drawings of the present application are provided for illustrative purposes only and, as such, the drawings are not drawn to scale. It is also noted that like and corresponding elements are referred to by like reference numerals. [0021] In the following description, numerous specific details are set forth, such as particular structures, components, materials, dimensions, processing steps and techniques, in order to provide an understanding of the various embodiments of the present application. However, it will be appreciated by one of ordinary skill in the art that the various embodiments of the present application may be practiced without these specific details. In other instances, well-known structures or processing steps have not been described in detail in order to avoid obscuring the present application. [0022] Referring to FIG. 1 , there is illustrated a reactive material stack 8 that can be employed in an embodiment of the present application. The reactive material stack 8 includes alternating layers of a first reactive material 10 and a second reactive material 20 , and a barrier layer 30 sandwiched between each layer of the first reactive material 10 and the second reactive material 20 . The reactive material stack 8 typically contains tens to about one hundred of these layers and has a total thickness from 0.5 μm to 10 μm, although greater or lesser thicknesses may be contemplated. [0023] The reactive material stack 8 can be formed over a substrate (not shown). The substrate can be a semiconductor substrate, a dielectric substrate, a conductive material substrate, or a combination thereof. In one embodiment, the substrate can include a bulk semiconductor substrate, a semiconductor-on-insulator (SOI) substrate or a III-V semiconductor substrate as known in the art. The substrate may also include metal lines and/or metal via structures embedded within at least one dielectric material layer. [0024] The first reactive material and the second reactive material are selected to react with one another in an exothermic reaction upon ignition. In one embodiment, such exothermic reaction produces sufficient heat to cause the alteration to the memory state of phase change memory (PCM) cells in integrated circuits. Exemplary sets of the first reactive material and second reactive material include, but are not limited to, Ni/Al, Al/Pd, Cu/Pd, Nb/Si and Ti/Al. Additional exemplary sets of the first and second reactive materials that may be used in embodiments of the present application are described in “A Survey of Combustible Metals, Thermites, and Intermetallics for Pyrotechnic Applications”, by Fischer et al., 32nd AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Lake Buena Vista, Fla., 1996, the disclosure of which is hereby incorporated by reference in its entirety. [0025] The reaction of the first and second reactive materials may be ignited by a mechanical stress, an electric spark, a laser pulse, or other similar energy ignition sources. Upon ignition, metal elements of the first reactive material and second reactive material intermix due to atomic diffusion to form an alloy, intermetallic or a composite of the first reactive material and the second reactive material. The change in chemical bonding, caused by interdiffusion and compound formation, generates heat in an exothermic chemical reaction. [0026] The layers of the first and second reactive materials 10 , 20 may be formed using conventional film deposition techniques such as, for example, physical vapor deposition (PVD) or chemical vapor deposition (CVD), atomic layer deposition (ALD), electroplating and spin-on (sol-gel) processing. The thickness of each layer of the first reactive material 10 and the second reactive material 20 may range from 1 nm to 200 nm, although lesser or greater thicknesses can also be employed. The thickness of the layers may be a constant or some layers may have a different thickness than others. [0027] Each barrier layer 30 acts as a diffusion barrier to reduce interdiffusion of the first and second reactive materials, thus preventing the reactions from taking place until a triggering event designated to initiate the reaction occurs. Each barrier layer 30 may include transition metals selected from Group IVB or VB of the Period Table of Elements, oxides of these transition meals, nitrides of these transition meals, aluminum oxide (Al x O y with x from 1 to 2 and y from 1 to 3) or combinations thereof. Exemplary transition metals include, but are not limited to, Ti, Zr, Hf, V, Nb and Ta. Each barrier layer 30 may be formed of a single layer structure or a multilayer stack (as shown in FIG. 2 ). In one embodiment, each barrier layer 30 includes a single layer of Ta. In another embodiment, each barrier layer 30 includes a stack selected from the group consisting of Ta/Ta x O y , Al x O y /Ta/Ta x O y or Al x O y /Ta/Ta x O y /Ta/Ta x O y . For example and as shown in FIG. 2 , each barrier layer 30 includes a five-layer stack of Al x O y (labeled as 32 in the drawing) and alternating layers of Ta (labeled as 34 in the drawing) and Ta x O y (labeled as 36 in the drawing) with x from 1 to 3 and y from 1 to 5. It should be noted that the number of alternating layers in the barrier layer stack is not limited to four layers as shown in FIG. 2 , other numbers of alternating layers can also be employed in the barrier layer stack. The thickness of each barrier layer 30 may be from 1 nm to 20 nm, although lesser and greater thicknesses can also be employed. [0028] The barrier layers 30 may be formed, for example, by PVD, CVD, ALD, electroplating or spin-on (sol-gel) processing. In one embodiment and when transition metal oxides or metal nitrides are employed in the barrier layer 30 , the transition metal oxide layer or the transition metal nitride layer may be formed by first forming a transition metal layer and converting a surface portion of the transition metal layer by thermal nitridation and/or thermal oxidation. [0029] Referring to FIG. 3 , there is illustrated another reactive material stack 8 ′ that can be employed in another embodiment of the present application. The reactive material stack 8 ′ includes alternating layers of a first reactive material 10 and a second reactive material 20 , and a barrier layer 30 sandwiched between each pair of the layer of the first reactive material 10 and the layer of the second reactive material 20 . Each layer is composed of the same material and can be formed by the same method as described above in FIG. 1 . [0030] The energy required to initiate the exothermic reaction is directly related to the physical properties, e.g., thickness and the composition of each barrier layer 30 . To illustrate the effects of the barrier layer 30 on the ignition temperatures of the reactive material stack 8 of the present application, a barrier layer or a barrier layer stack of the present application is introduced between an Al layer and a Ni layer. In a first example and when a single barrier layer is employed, a first exemplary reactive material stack of the present application includes, from bottom to top, 20 nm Al/10 nm Ta/10 nm Ni formed over a SiO 2 coated Si substrate. In a second example and when a barrier layer stack is employed, a second exemplary reactive material stack includes, from bottom to top, 20 nm Al/Al x O y /5 nm Ta/Ta x O y /5 nm Ta/Ta x O y /10 nm Ni formed over a SiO 2 coated Si substrate. The oxide layers in the second example were formed by exposing the structure to an air break after deposition of each metal layer. The ignition temperatures obtained from the first and second exemplary reactive material stacks are compared with a conventional reactive material stack composed a bilayer of 20 nm Al and 10 nm Ni formed over a SiO 2 coated Si substrate. [0031] FIG. 4A shows a sheet resistance of the conventional reactive material stack as a function of temperature and FIG. 4B shows a X-ray diffraction (XRD) profile of the conventional reactive material stack as a function of temperature at a heating rate of 3° C./s in a helium ambient. As shown in FIG. 4A , the sheet resistance initially increases linearly with increasing of temperature but deviates from linearity at about 260° C., indicating that at about 260° C. the reaction between Al and Ni proceeds to form an Al 3 Ni 2 alloy. The phase change at about 260° C. is also evidenced in the XRD profile. As shown in FIG. 4B , phases of Al and Ni disappear while a new Al 3 Ni 2 phase appears after heating to 260° C. Thus, both sheet resistance and XRD measurements indicate that a temperature of 260° C. at a ramp rate of 3° C./scan trigger the reaction of Al and Ni. [0032] FIG. 5A shows a sheet resistance of the first exemplary reactive material stack of the present application as a function of temperature and FIG. 5B shows a XRD profile of the first exemplary reactive material stack as a function of temperature at a heating rate of 3° C./s in a helium ambient. As shown in FIG. 5A , the sheet resistance initially increases linearly with increasing of temperature but deviates from linearity at about 400° C., indicating that at about 400° C. the reaction between Al and Ni proceeds to form an Al 3 Ni 2 alloy. The phase change at 400° C. is also evidenced in the XRD profile. As shown in FIG. 5B , phases of Al and Ni disappear while a new Al 3 Ni 2 phase appears after heating to 400° C. This means that a reaction temperature of 260° C. is not sufficient to trigger the reaction of Al and Ni when a Ta barrier layer is present therebetween, but rather a temperature above 400° C. is needed. Thus, by introducing a 10 nm Ta barrier layer between the Al layer and Ni layer, the reaction temperature for Al and Ni couples can be increased to 400° C. [0033] FIG. 6A shows a sheet resistance of the second exemplary reactive material stack of the present application as a function of temperature and FIG. 6B shows a XRD profile of the second exemplary reactive material stack as a function of temperature at a heating rate of 3° C./s in a helium ambient. As shown in FIG. 6A , the sheet resistance initially increases linearly with increasing of temperature, but deviates from linearity at about 571° C., indicating that at about 571° C. the reaction between Al and Ni proceeds to form an Al 3 Ni 2 alloy. The phase change is also evidenced in the XRD profile. As shown in FIG. 6B , phases of Al and Ni remains at a temperature around 571° C. Thus, by introducing a barrier layer stack between the Al layer and Ni layer, the reaction temperature for Al and Ni couples can be increased to 571° C. [0034] FIG. 6C shows an sheet resistance of the second exemplary reactive material stack as a function of heating time when the second exemplary reactive material stack is held isothermally at 400° C. for 4 h. As shown in FIG. 6C , there is no increase in sheet resistance as time passes, indicating that the reaction between Al and Ni does not occur at 400° C. [0035] FIG. 7 is a graph summarizing ignition temperatures of reactive material stacks employing various barrier layers of the present application. Each reactive material stack has a structure represent by 10 nm Ni/X/20 nm Al/SiO 2 , and X represents a barrier layer of the present application. As shown in FIG. 7 , by varying the composition and thickness of the barrier layers, the reaction temperature of the reactive material stacks including Al and Ni reactive material pairs can be tailored to be from 260° C. to 571° C. [0036] In the present application, by introducing a barrier layer between layers of the first reactive material and second reactive material, the ignition temperature of resulting reactive material stacks can tuned. The reactive material stacks thus formed are benign during the chip fabrication and chip operation, but can be ignited when a triggering event occurs at a desired time. Further, by varying composition and thickness of the barrier layer of the present application, the ignition temperatures of the reactive material stacks can be tuned. The design flexibility can be greatly improved. [0037] While the application has been described in terms of specific embodiments, it is evident in view of the foregoing description that numerous alternatives, modifications and variations will be apparent to those skilled in the art. Each of the embodiments described herein can be implemented individually or in combination with any other embodiment unless expressly stated otherwise or clearly incompatible. Accordingly, the application is intended to encompass all such alternatives, modifications and variations which fall within the scope and spirit of the application and the following claims.

A reactive material stack with tunable ignition temperatures is provided by inserting a barrier layer between layers of reactive materials. The barrier layer prevents the interdiffusion of the reactive materials, thus a reaction between reactive materials only occurs at an elevated ignition temperature when a certain energy threshold is reached.

[0001] The present invention relates to ventilatory assist devices and more particularly to a lightweight emergency ventilatory assist device that can be retrofitted onto a conventional protective mask without removing the mask, for example, to provide CPAP in situ, i.e. without having to transport the patient to a medical facility. BACKGROUND OF THE INVENTION [0002] The ability to immediately treat respiratory distress substantially reduces the number of fatalities sustained during military operations. Civilian emergency medical technologists stress the concept of the “golden hour.” This interval represents the average time that elapses before a patient with serious or multiple injuries will begin to deteriorate rapidly. Without the ability to deliver on-scene medical support, casualties must be transported to a medical facility for treatment. This is often impossible during active operations. [0003] Treatment of these casualties in a nuclear-biological-chemical (NBC) environment is even more difficult. Casualties that occur in an NBC environment that require breathing assistance must be performed with extreme caution so as not to contaminate the casualty or the rescuer. When treating a casualty exposed to a nerve agent, it has been proposed that a cricothyroidotomy is the most practical means of providing an airway for assisted ventilation using a hand-powered ventilator equipped with an NBC filter. As part of that proposed practice, when the casualty reaches a medical treatment facility (MTF) where oxygen and a positive pressure ventilator are available, the hand-powered ventilator and NBC filter are employed continuously until adequate spontaneous respiration is resumed. [0004] Performing a cricothyroidotomy in the field may be difficult during ongoing operations. A method to provide ventilation assistance to a casualty through an existing protective mask may save time and prevent further casualties. [0005] Another situation facing today's Army is a chemical attack on a large group without protective masks in place. This situation may require the ventilation of hundreds of individuals making the large-scale availability of small lightweight, automatic ventilators useful. [0006] While there are several ventilators designed for far-forward medical care, for various reasons these ventilators fall short of what is ideal for first response in the operational environment. For example, some are too heavy to be carried on foot. Some require an external source of pressurized gas or power. [0007] A non-invasive positive pressure respiratory assist device that could be retrofitted onto a protective mask by the patient or another individual without medical training would provide optimize the resources that are available to attend to casualties in military, civil defense, firefighting and settings of an industrial nature. SUMMARY OF THE INVENTION [0008] In one aspect, the invention is directed to a mask interface device for a protective mask of the type having a mask filter and a mask expiratory port, the mask expiratory port having an expiratory port valve of the type that is normally closed and openable upon expiration, the mask filter having an inspiratory air inlet, the mask interface device comprising: a mask interface assembly mountable to the mask and having a mounting interface for mounting an air pressure generator in fluid communication with the inspiratory inlet of the mask filter; and an expiratory port interface assembly mountable to the mask expiratory port and comprising at least one opening for venting expired gas to atmosphere and a one-way valve that is positioned to control the flow of expired gas out through the at least one opening, and wherein the one-way valve is set to an opening pressure that provides positive end expiratory pressure or PEEP. Optionally, this opening pressure is between 2.5 and 20 cm H 2 O. Optionally, the mask interface device interfaces directly with the mask filter. In one embodiment of the invention, this interface does not require the filter to have a mating connection and is therefore is universal for a broad class of filters, for example cylindrical filters that project from the mask. Such a cylindrical filter may be of known dimension and other characteristics that may serve as a standard to which a mask interface assembly may be designed. For the sake of convenience, filters serving as a basis for design of the mask interface assembly may be referred to herein as universal filters. [0009] The invention is also directed to a kit comprising a mask interface assembly and an expiratory port interface assembly. Optionally the kit includes a case sized to include both the mask interface assembly and an expiratory port interface assembly. Optionally the case comprises a belt clip. Optionally the mask interface device comprises an air-pressure measuring device. Optionally, the mask interface device or kit comprises an air pressure generator. [0010] In another aspect, the invention is directed to a mask interface device for a protective mask of the type having a mask expiratory port, the mask expiratory port having an expiratory port valve of the type that is normally closed and openable upon expiration at an expiratory port valve opening pressure, the mask interface device comprising an expiratory port interface assembly mountable to the mask expiratory port and comprising at least one opening for venting expired gas to atmosphere and a one-way valve that is positioned to control the flow of expired gas out through the at least one opening, and wherein the way valve is set to an opening pressure that provides positive end expiratory pressure or PEEP. Preferably, the opening pressure of the one-way valve is set or settable to a value greater than the expiratory port valve opening pressure. Preferably, the opening pressure of the one-way valve is set or settable to a value that is less than the intra-mask pressure generated by an air pressure generator. Optionally, the mask interface device comprises or is fluidically connectable to an air-pressure measuring device. The air-pressure measuring device may alternatively be configured to sealably mate with the drinking port of the protective mask. Optionally, the mask interface device includes a pressure-relaying interface associated with an air-pressure measuring device, for example air sampling port that is positioned to enable the pressure of gas exiting the expiratory port valve to be measured. The invention is also directed to a kit comprising a mask interface device the mask interface device comprising an expiratory port interface assembly mountable to the mask expiratory port and comprising at least one opening for venting expired gas to atmosphere and a one-way valve that is positioned to control the flow of expired gas out through the at least one opening, and wherein the way valve that is set to an opening pressure that provides positive end expiratory pressure or PEEP. Optionally the kit comprises an air-pressure measuring device. Optionally, the kit further includes a mask interface assembly as define above. Optionally, this mask interface assembly comprises an air pressure generator that is set or settable to control the intra-mask pressure in response to pressure measured by the air-pressure measuring device. [0011] In another aspect, the invention is directed to a mask interface device for a protective mask of the type having a mask expiratory port, the mask expiratory port having an expiratory port valve of the type that is normally closed and openable upon expiration at an opening pressure that provides positive end expiratory pressure, the mask interface device comprising an expiratory port interface assembly mountable to the mask expiratory port and comprising at least one opening for venting expired gas to atmosphere, a one-way valve that is positioned to control the flow of expired gas out through the at least one opening, and an air-pressure measuring device or a pressure-relaying interface (that is associated with an air pressure measuring device, for example air sampling port), that is positioned to measure the pressure of gas exiting the expiratory port valve, and wherein the one-way valve that is set to open at an opening pressure that is greater than the expiratory port valve opening pressure. Preferably, the opening pressure of the one-way valve is set or settable to a value that is less than the intra-mask pressure generated by an air pressure generator. The invention is also directed to a kit comprising the latter mask interface device. The term “air pressure measuring device” may be used for convenience to refer a port or other interface for such a device, and is not meant to imply that the device is physically located in or outside the expiratory port valve so as long as it is operatively associated with the valve to measure pressure of gas exiting the valve. The foregoing notwithstanding that the disclosure may in other instances explicitly refer to the device as being operatively associated with the valve. [0012] In one aspect, the invention is directed to a mask interface device for a protective mask of the type having a mask filter and a mask expiratory port, the mask expiratory port having an expiratory port valve of the type that is normally closed and openable upon expiration, the mask filter having an inspiratory air inlet, the mask interface device comprising an air pressure generating assembly having a an air pressure generator in fluid communication with the inspiratory inlet of the mask filter and an expiratory port interface assembly mountable to the mask expiratory port and comprising at least one opening for venting expired gas to atmosphere, one-way valve that is positioned to control the flow of expired gas out through the at least one opening and an air-pressure measuring device or a pressure-relaying interface (that is associated with an air pressure measuring device, for example air sampling port), that is positioned to enable the pressure of gas exiting the expiratory port valve to be measured, and wherein the way valve that is set to open at an opening pressure that is equal to or greater than the expiratory port valve opening pressure. Optionally, the aforesaid device further comprises a controller for controlling the output pressure of the air-pressure generating device in response to pressure measured by the air-pressure measuring device. [0013] A variety of technologies for measuring pressure are well known to those skilled in the art including pressure transducers and sensors having an air sampling port. [0014] Optionally, the air pressure generator optionally included within the aforementioned mask interface devices or kits are electrically powered and the mask interface device or kit comprises a controller connectable to the pressure sensor to receive pressure measurement output and operatively connectable to the air pressure generator to achieve a selected mask air pressure in response to output of the pressure sensor. Optionally the air pressure generator is a blower powered by a motor and the controller controls the motor speed. Optionally, the blower is a radial blower having a low rotational mass for power efficiency. Optionally the expiratory port interface device is operatively connected to a one-way valve that is set to an opening pressure that provides positive end expiratory pressure or PEEP. Optionally this valve is a mechanical valve that opens at more than one selected pressure. Optionally this valve is microprocessor controllable to achieve a variety of opening pressures. Optionally the motor controller is set to maintain a mask pressure that equals or exceeds the opening pressure of this valve at any given time. Optionally, the expiratory port interface assembly is mountable to the mask to create a chamber at least partially defined by the said mask expiratory port valve and the one-way valve and wherein said chamber is fluidly connected with the pressure sensor. Optionally, the air pressure generator assembly is secured to the mask filter with a rollable resilient sleeve. Optionally, the rollable resilient sleeve includes a lip portion at one end upon which the sleeve may be rolled. Optionally, the sleeve is capable of being annularly mounted on a receptacle portion of the assembly, the receptacle portion of the assembly having a mouth portion for receiving the filter. Further aspects and embodiments of the invention pertaining to the sleeve will be discussed below. [0015] According to another aspect of the invention, the invention is directed to a mask interface device comprising: [0016] a filter receptacle, the filter receptacle having a mouth portion for receiving a filter; [0017] a rollable sleeve of elastic material; and [0018] a coupling interface for a respiratory device, the coupling interface defining an aperture to establish a fluidic communication between the respiratory device and the cylindrical filter and adapted to position the respiratory device in fluid communication with the filter. In one embodiment, the mask is a protective mask. In one embodiment the filter is a cylindrical filter dimensioned to a standard. In another embodiment the mask is pneumatically sealable around the face or head of the user to prevent contaminants form entering the mask. [0019] The inventions is also directed to a kit comprising the protective mask interface device. [0020] As used herein the term fluid or fluidic communication and similar terms refer to a pneumatically efficient communication to prevent substantial loss of airflow continuity and where air pressure is concerned to prevent a substantial loss of air pressure. What may be substantial in one type of application may not be in another. The term fluid communication is used distinctly from a sealed communication that is required to prevent noxious elements from entering the mask. The rolled sleeve of resilient material may be adapted for both fluid and sealed types of types communication, though the context in which it is used may not require the latter type of communication. The term respiratory device is used broadly to refer to any device that would be useful for coupling with a mask and mask filter including an additional filter, an air pressure generator, a source of oxygen etc. The air pressure generator may of the type that is manually operable to generate pressure or a source of compressed air. Optionally the protective mask filter interface device of the invention is coupled to an electrically powered air pressure generator. Optionally this device is included in a kit with an expiratory port interface assembly as generally defined herein with optional fluidic connection to a pressure sensor. Optionally, the kit further comprises one more of parts 100 , 300 and 400 ( 400 , if the device includes a pressure sensor and the pressure sensor is not in the expiratory port interface assembly) as described hereafter. Optionally, the protective mask interface is fluidically connected to a blower. Optionally this latter device has any one or more of the features of the air pressure generator assembly defined above and hereinafter. [0021] Optionally, the rollable sleeve of elastic material includes circular lip. Optionally the lip is approximately 0.25 inches in diameter. Optionally the intended lip portion is integrally formed with the sleeve, loosely rolled on itself, at one end, and glued to form the lip diameter. Optionally the sleeve is positionable in relation to the receptacle so as to free the mouth of the receptacle to receive the mask filter. To this end, the receptacle optionally comprises an annular indent portion to seat the sleeve in a rolled position proximal to the mouth of the receptacle. This annular indent serves as one type of means to resist inadvertent unrolling. Such “unroll resistor” may take a variety of forms and the may comprise one or more devices such as fasteners for example a Velcro type fastener. The annular groove may be of smaller diameter than the widest diameter of the receptacle. Optionally the receptacle slopes to a smaller diameter at its mouth in order to enable the cuff to be rolled quickly over the first portion of the mask filter so that it is quickly held in place while it is fully unrolled. Another form of unroll resistor may be an annular bead of wider diameter than the point of attachment of the sleeve so as to provide a cuff retaining hump. [0022] A variety of different sleeve materials of a circumferentially stretchable and optionally noxious resistant nature are well known to those skilled in the art. For example a suitable material is a neoprene covered latex material. This material may be cotton-flocked. This material may have a thickness of approximately 30 mils and may be sized to stretch circumferentially to a diameter 10-25% (optionally between 10 and 15%) greater than its resting diameter in order to form a tight fit over the mask filter. The lip may be formed to have a smaller diameter than the rest of the sleeve (for example 5% smaller). Optionally the length of the sleeve is such that the sleeve, when fully unrolled, positions the lip within a smaller diameter, for example in an indent or optionally behind the mask filter, for example, in the space between the cartridge and the mask. [0023] In another aspect, the invention is directed to mask interface device for a protective mask of the type having a mask filter and a mask expiratory port, the mask filter having an inspiratory air inlet, the mask expiratory port having an expiratory port valve of the type that is normally closed and openable upon expiration, wherein the expiratory port valve is openable at an expiratory port valve pressure, the device comprising: [0024] an air pressure generator assembly mountable to the mask in fluid communication with the inspiratory inlet of the mask filter, the air pressure generator assembly including an air pressure generator that is controllable to generate pressurized air at a selected mask air pressure; [0025] an expiratory port interface assembly comprising at least one opening for venting expired gas to atmosphere and a one-way valve that is positioned to control the flow of expired gas out through the at least one opening, wherein the one-way valve is openable at least one selected valve pressure in response to the flow of expired gas out of the mask expiratory port valve, and wherein the at least one selected valve pressure is preferably greater than the expiratory port valve pressure; [0026] a pressure measurement device; [0027] a controller connected to the pressure measurement device to receive pressure measurement device output and operatively connected to the air pressure generator to regulate the air pressure generated by the air pressure generator to achieve the selected mask air pressure in response to output of the pressure measurement device wherein the selected mask air pressure matches a selected valve pressure; [0028] and wherein the expiratory port interface assembly is mountable to the mask to create a chamber at least partially defined by the said mask expiratory port valve and the one-way valve and wherein said chamber is fluidly connected with the pressure measurement device. The term “matches” means that the selected pressure generated by the air pressure generator equals or is greater than the selected opening pressure of the one-way valve. It is to be understood that the mask interface device is adapted to create a biased unidirectional air into the mask and then out the mask expiratory port valve and through the one-way valve to atmosphere. Optionally, the mask pressure is set to a value that is only slightly greater that the opening pressure of the one way valve so as to maintain flow which maintains the mask expiratory valve sufficiently open to equilibrate the pressure between the mask and chamber or closed volume but otherwise not greater so as to preserve battery power. This flow is generated by the air pressure generator at a target mask pressure that is required for the type of ventilatory support required by the user of the mask and is concomitantly set to maintain the expiratory port valve open almost continuously (except upon sudden inspiration) so that pressure sensor substantially measures the pressure in the mask. Accordingly, the term “closed volume” means a space downstream of the expiratory port valve in fluid communication with the pressure sensor which preferably has a pressure virtually always substantially equilibrated with that of the mask. To accomplish this end this chamber does not need to be sealed and some air escape, for example, through an unsealed one-way valve, serves to maintain a biased airflow that keeps the expiratory port assembly free of contaminants. [0029] As described above, the expiratory port assembly valve is preferably set at or adjustable to a pressure value that provides positive end expiratory pressure (PEEP). Optionally, the expiratory assembly valve sees atmospheric pressure and provides the selected PEEP value at different atmospheric pressures. Optionally, the selected PEEP value is approximately 10 cm H 2 O. Optionally, the expiratory port interface assembly includes a locking mechanism for securing it to the mask expiratory port. Optionally, the locking mechanism is of a type that is engaged after the expiratory port interface assembly is finally positioned on the mask expiratory port. Optionally, the locking mechanism comprises a slidable ring that slidably engages a sleeve shaped clamp (mounted over the mask expiratory port) by way of cam action. [0030] According to one aspect of the invention, the air pressure generator creates a biased airflow within the expiratory port assembly such that the expiratory port valve (which may be of the type that normally requires minimal pressure to open) is now “normally” continuously biased into an open position (normally in this case meaning except upon occasional sudden deep inspiration, which only for a short duration desirably closes the mask expiratory port valve to prevent contamination of the interior of the mask) and therefore the pressure sensor is normally measuring the pressure in the mask. Normally, the biased airflow prevents the interior of the mask from contamination. Optionally, the PEEP valve is not sealed and constantly leaks air to enhance the biased airflow. [0031] The mask interface device of the invention may be used to provide a variety of types of respiratory support, for example pressure cycled types of support such as such as CPAP (typical target mask pressure range: 0-15 cm H 2 O, typical PEEP setting range: 2.5 to 12.5 cm H 2 O), bi-level CPAP (BiPAP), controlled ventilation and assist control ventilation (typical target mask pressure range: on inspiration 0-40 cm H 2 O, on expiration: 0-15 cm H 2 O, typical PEEP inspiratory setting range: 10 to 40 cm H 2 O, typical PEEP expiratory setting range: 0 to 15 cm H 2 O), pressure support (typical target mask pressure range: on inspiration 0-40 cm H 2 O, on expiration: 0-15 cm H 2 O, typical PEEP setting range: 5 to 15 cm H 2 O, and proportional pressure support (typical target mask pressure range: on inspiration 0-40 cm H 2 O, on expiration: 0-15 cm H 2 O, typical PEEP setting range: 5 to 20 cm H 2 O) and volume cycled types of support such as controlled ventilation, assist control ventilation and proportional volume ventilation (bellows fill to a volume set mechanically and then empty—typical volume range: 0-1000 cc, typical PEEP setting range: 2.5 to 15 cm H 2 O). For the sake of convenience, the ventilating pressure (irrespective of value) generated in the mask by the pressure generator will be referred to as a “controlled intra-mask pressure”. [0032] For controlled ventilation, the microprocessor controller may use a closed loop feedback loop to adjust blower speed to change airway flow (or rate of bellows movement) at a prescribed rate to achieve a target volume in a targeted time period and then may release pressure via PEEP for expiratory time and then repeat the cycle. The microprocessor would provide the required timing and monitor pressure to warn or release pressure if thresholds are exceeded. The motor may of a type capable to deliver 60 LPM at the maximum required peak pressure setting plus accommodate a pressure drop from dirty filter at nominal 12 VDC. An 18 VDC battery provides room for overdriving on a nominal 16-18 VDC to ramp up speeds quickly. Similar in most respects, but by way of contrast, for assist control ventilation inhalation is timed to match patient respiratory rate unless it falls below a preset minimum rate. In the case of proportional volume ventilation, a respiratory effort sensor may be used to determine what pressure to use. [0033] Depending on the type of support provided, other types of sensors and measurement devices may be useful, for example, those that measure for in-flow and out-flow, airway pressure, airflow, time and respiratory effort such as diaphragm EMG and phrenic nerve discharge. [0034] Depending on the type of support provided, other type of expiratory port interface assembly valves may be preferred. For example, for BiPAP a preferred valve would be a mechanical pressure relief valve with precalibrated settings adjusted between 2 levels by a motor or other actuator. [0035] Medical indications for ventilatory support are well known to those medically skilled in the various military, industrial, firefighting, aviation and oil and other mining arts. In military settings typical indications for ventilatory support include cardiovascular diseases such as pulmonary edema, lung disease such as trauma, bleeding, edema, infection, embolization, aspiration of water or other substances, inhalation injury from toxic gases or heat, and assistance in the case of paralysis, loss of chest wall compliance or increased airway or mask resistance. [0036] According to another aspect, the invention is directed to a method of providing non-invasive positive pressure ventilation in junction with a protective mask of the type having a mask filter and a mask expiratory port, the mask expiratory port having an expiratory port valve of the type that is normally closed and openable upon expiration, the mask filter having an inspiratory air inlet, the method comprising: (a) mounting an air pressure generator (component 1 ) onto the mask in fluid communication with the inspiratory air inlet of the mask filter and b) mounting an expiratory port interface assembly on to the mask expiratory port, the mask expiratory port interface assembly (component 2 ) comprising at least one open end for venting expired gas to atmosphere and a one-way valve that is positioned to control the flow of expired gas out through the at least one opening, and wherein the one-way valve is set to an opening pressure that provides positive end expiratory pressure or PEEP. [0037] The air pressure generator and expiratory port interface assembly are mounted synchronously or in sequence. In the latter case, the invention is also directed to performing the last in a series of cooperative sequential steps as described hereafter performed by a single or different entities. Optionally, one of the components may be pre-mounted in the course of manufacture or preparation of the device. Optionally, a subject using wearing the mask mounts both components, optionally when wearing the protective mask. Optionally, the air pressure generator is mounted first and turned on before the expiratory port assembly is mounted. Optionally, the mask is in fluid communication with an air-pressure measuring device. Optionally, the air pressure generator is in fluid communication with a controller that controls the pressure generated by the air-pressure generating device in response to the measurements of the air pressure measuring device. Optionally, the method further comprises a step of measuring air pressure in the mask. Optionally, the method further comprises the step of controlling the air pressure generated by the air-pressure generating device in response to measurements obtained by the air-pressure measuring device. BRIEF DESCRIPTION OF THE DRAWINGS [0038] FIG. 1 is a perspective view of a mask interface device of the invention showing the positioning of the mask interface device relative to mask when the user wearing the mask wishes to retrofit the device onto the mask. [0039] FIG. 2 is a sectional view of the mask interface assembly. [0040] FIG. 3 shows a mask interface device of the invention retrofitted on to the mask. [0041] FIG. 4 is an exploded view of the mask interface assembly. [0042] FIG. 5 is another exploded view of the mask interface device assembly showing a different perspective. [0043] FIG. 6 shows a partial sectional view of the mask interface device showing the airflow path through the device. [0044] FIG. 7 is a cross-sectional view of the expiratory port interface assembly. [0045] FIG. 8 is an exploded view of the expiratory port interface assembly. [0046] FIG. 9 is an exploded view of the expiratory port interface assembly in section. [0047] FIGS. 10 a and 10 b show unlocked and locked perspectives of mask expiratory port interface assembly in relation to the mask. [0048] FIG. 11 is a sectional view of another embodiment of the mask interface device. DETAILED DESCRIPTION OF THE INVENTION [0049] As generally shown in FIG. 1 , according to one embodiment of the invention, the mask interface device of the invention may optionally include a mask filter interface assembly 100 and an expiratory port interface assembly 200 which are adapted to fit on to a mask filter 1 and a mask expiratory port 2 , respectively. Optionally, the mask filter is of a generally cylindrical shape. Optionally the mask filter is in cartridge form. The term “mask” is used broadly to include a pneumatically isolated (air-pressure retaining) face or head portion of any protective garment or hood that has a cylindrical mask filter. Optionally, the mask may be of the protective type that is pneumatically sealed for preventing inflow of noxious elements. For military applications, the mask is optionally a M40 gas mask outfitted with the NATO C2 cartridge (thread NATO/EN 148-1, 40 mm). Other masks and cartridges are well known to those skilled in the various military, industrial, firefighting, aviation, mining and medical arts (e.g. see http://www.approvedgasmasks.com/). A typical mask 26 to which various embodiments of the invention may be adapted may have left and/or right inspiratory ports 3 to which a mask filter cartridge 1 can be attached. The cartridge 1 is typically mounted by screwing a threaded portion of the cartridge (seen in FIG. 2 ) into the corresponding threaded portions of the ports 3 (not shown). The mask also typically includes transparent lens elements 7 and a voice communication port 5 and straps 6 which sealably affix the mask to the user's face. [0050] As shown in FIGS. 1 and 2 , the mask interface device of the invention includes a mask filter interface assembly 100 that includes an air pressure generating device. Optionally the air pressure generating device requires electrical power to run, for example according to one embodiment of the invention, a motor driven blower 180 . The air pressure generator may be powered via a battery pack 1001 associated with an electrical cable 300 . Other types of air pressure generators include pumps and sources of compressed air. According to one embodiment of the invention, as shown in the drawings described hereafter, the air pressure generator is a radial blower (for example model U51DX-012KK5 made by Micronel AG which operates at 12 VDC) and the battery pack 1001 that generates sufficient power to power the blower for the application of interest. The battery pack 1001 may be selected to provide excess power, for example, 18 VDC, to power the blower. The blower motor speed may be controlled with pulse width modulated signals and pressure sensor output may be used for closed-loop feedback to maintain a desired output pressure. Pressure settings for continuous positive airway pressure optionally range from 1 to 15 cm H 2 O. For example, a target mask pressure setting of 10 cm H 2 O with PEEP set at 10 cm H 2 O may be preferred for some applications. The blower is preferably able to run continuously at required peak pressure settings as well as accommodate pressure drops from a dirty filter, at nominal 12 VDC. With extra battery power there is room for overdriving on a nominal 16-18 VDC rail to ramp up speeds quickly. The motor may be ramped up to full speed when a pressure drop of any magnitude is ascertained, in order maintain a continuous pressure level in the mask and biased airflow through the mask expiratory port valve 111 . [0051] The expiratory port interface optionally includes elements of assembly 200 . According to one embodiment of the invention, the expiratory port interface is in fluid communication with a respiratory treatment parameter measuring device, for example a pressure sensor. Suitable pressure sensors include those that measure pressures in the 0-40 cm H 2 O range and are well known to those skilled in the art. [0052] Optionally the pressure sensor may be used to control the pressure generated by the air pressure generator using a feedback control mechanism. Optionally, the pressure sensor 2001 (seen in FIG. 4 ) is located in proximity to a control board 130 which supports a controller (not shown) that receives output from the pressure sensor 2001 and uses this output to control the pressure applied by the air pressure generator to control the intra-mask air pressure. Optionally, the expiratory port interface assembly includes an air sampling port 18 shown in FIGS. 6 and 7 to sense pressure within the expiratory port interface assembly. The sampling port 18 is optionally in fluid communication via conduit 400 with the pressure sensor, which may be optionally located in the housing of the mask filter interface assembly 100 . When the expiratory port interface assembly 200 is secured to the mask expiratory port 3 expired air vents to atmosphere via apertures 44 . [0053] As shown in FIGS. 2 , 3 , 4 , 5 and 6 the air pressure generator assembly is fitted with a cuff 14 , which includes a sleeve portion 16 rolled around a circular lip portion 20 best shown in FIGS. 2 and 4 . When the sleeve portion is snugly rolled around the lip the sleeve may be easily unrolled over the mask filter cartridge. [0054] As shown more particularly in FIG. 2 , according to one embodiment of the invention, the mask filter interface assembly 100 may optionally be adapted to receive or house an air pressure generator in the form of a blower 180 . The mask filter interface assembly 100 may comprise two primary housing elements 102 and 104 . Housing element 102 is the mask filter interface portion of the housing and housing element 104 interfaces with the blower 180 . Housing element 102 comprises a receptacle portion 108 for sliding over a mask filter cartridge. [0055] As seen in FIG. 4 , 5 , and in some respects 6 , a u-shaped slot defines air channel portion 112 of the housing 102 and aligns with the air inlet aperture 4 on the mask filter cartridge 1 (see also FIG. 4 ). Referring also to FIG. 4 , housing element 102 also comprises an annular indent portion 116 (best seen in FIGS. 2 and 4 ), which optionally extends entirely around the receptacle portion 108 of the housing 102 , in proximity to the mouth of the receptacle 109 and which optionally serves as both a seat for the cuff 14 and a point of attachment of the free end of the sleeve 105 (for example using a suitable adhesive) opposite the other free end defined by the lip portion 20 . Receptacle portion 108 optionally also includes a ramp portion 110 which is of intermediate diameter relative the mask cartridge diameter and the largest diameter of the annular indent portion 116 of the receptacle 108 . This ramp portion facilitates rolling the cuff 14 down onto the smaller diameter mask filter cartridge 1 . Thus, when a subject wearing the mask positions the mask interface assembly onto the cartridge an initial gripping force is applied to the cartridge to quickly secure its positioning pending complete unrolling of the cuff. As described above, cuff 14 comprises a sleeve portion 16 (best shown in FIG. 3 ) and a circular lip portion 20 , which provides a suitably shaped surface onto which the cuff sleeve 16 may be rolled and unrolled. Housing element 102 further comprises an air inlet portion 119 , which is in operative alignment with the air inlet port 150 of the blower 180 . The air inlet portion of housing element 119 comprises slot-like apertures 126 which may be integrally formed with this portion of the housing. Filter 140 , bolster 142 , and spacing ring 144 are generally seated within the cone shaped portion 119 of housing element 102 , bolster 142 having a rigid mesh-like constitution serving to support the filter 140 . [0056] As shown in FIGS. 2 , 4 and 5 housing element 104 comprises an inclined ramp portion 146 , which deflects air emerging from the outlet port 182 of the blower so that it deflected through slot 112 and into intake port 4 of the mask filter cartridge 1 . [0057] As shown in FIGS. 4 and 5 , housing element 102 includes a plurality of smaller ports 118 , 120 , 122 and 124 , respectively. Circular port 118 receives the air-pressure sampling conduit 400 shown in FIGS. 1 and 3 while circular port 120 receives electrical cable 300 . The conduit 400 and cable 300 both interface with controller elements in the control board 130 . Conduit 400 slides over an air conduit interface port 2001 a of a pressure-sensing device 2001 on the control board 130 . Triangular reference port 124 is an atmospheric pressure reference port. A conduit (not shown) leads from cylindrical interior portion of this port to a pressure measurement device on the control board 130 . By measuring atmospheric pressure and pressure in the mask the controller is able to adjust the speed of the blower motor to maintain a constant or varying desired pressure above atmospheric pressure (as the downstream side of the one way valve in the expiratory port interface assembly sees atmospheric pressure via apertures 44 ). Triangular port 122 is a vent port for the space containing the control board. This enables pressure to be equalized within this space and atmosphere. Filter elements 117 recessed within ports 122 and 124 prevent the entry debris via these ports. Fastener receptacles 130 a and support element 130 b support the control board 130 in spaced relation to the back-plate 108 a of receptacle 108 . Apertures 130 c (for receiving fasteners—not shown) the control board 130 interface align with receptacles 130 a. [0058] The expiratory port interface assembly is described in detail in FIGS. 6 , 7 , 8 , 9 , 10 a and 10 b. [0059] By way of overview, as shown in cross-section in FIGS. 7 and 9 , components of the expiratory port interface assembly include toothed gripping element 16 , gasket 30 and valve seat element 28 , which directly interface with mask expiratory port 2 (shown in FIG. 7 with dotted lines to illustrate the interface). [0060] By way of overview with initial reference to FIG. 6 , and then FIGS. 7 , 8 , 9 , 10 a and 10 b using a one way airflow path from blower air intake port 150 →through blower outlet port 182 →in filter inlet port 4 →out mask expiratory port valve flap 111 (not seen)→out expiratory port interface assembly valve flap 144 →out expiratory port interface apertures 44 - - - to provide a directional frame of reference for airflow, valve seat element 28 defines a L-shaped annular seat 993 for gasket 30 on its upstream side and an annular valve seat 998 for compression spring 888 mounted valve flap 144 on its downstream side. Valve flap 114 is exposed to atmospheric pressure via apertures 44 on its downstream side. [0061] More generally, one way expiratory port interface assembly valve (shown as comprising spring elements 888 , valve seat 998 and valve flap 144 ) may be a mushroom valve, a spring actuated valve, a fixed orifice or a leak voltage controlled variable orifice valve. Silicone valves made by liquid injection molding and sold under the trademarks SureFlo and MediFlo are optional alternatives (http://www.Imselastovalves.com/mediflosureflo%20design.htm). [0062] By way of overview, as best shown in FIGS. 7 and 9 , when the expiratory port interface assembly 200 is secured onto mask expiratory port 2 , the inner walls 2 b of mask expiratory port 2 , the inner walls 28 a of valve seat element 28 , the downstream side of mask expiratory port flap 111 and the upstream side of valve flap 144 define, in effect, a closed volume or chamber which is in direct fluid communication with air pressure sampling port 18 . The term “closed volume” as used herein refers to a chamber defined in part by an one-way upstream valve (in one embodiment the mask expiratory port valve) that normally seals upon inspiration and a one-way downstream valve (expiratory port interface assembly valve) that is openable in response to at least one set pressure and wherein both valves are biased into a closed position pending creation of a biased airflow (by turning on the blower 180 —optionally, after the mask interface assembly is secured and before the expiratory port interface assembly is secured) to establish fluidic continuity between the mask and the otherwise normally closed volume. [0063] As described above, according to one aspect, the invention is directed to a mask interface device which is adapted to provide positive pressure ventilatory assistance with feedback loop pressure control that can be rapidly deployed by an individual in a contaminated environment without removing the mask or compromising its protective structural integrity. Optionally, by creating the chamber as aforesaid which (absent airflow) is biased to be a closed volume and despite the imposed positioning of the air pressure sampling port downstream of the of mask expiratory port flap 111 (so as not compromise the structural integrity of the mask), pressure can be measured in the mask from within the chamber by using the controller to maintain an airflow that biases the mask expiratory port flap 111 and expiratory port interface flap 114 into an open position. This is optionally accomplished by maintaining the mask pressure at a predetermined level that equals or exceeds the opening pressure of flap 114 . The continuously biased flow of air prevents contaminants from building up in the transiently closed volume and entering the mask via mask expiratory port flap 111 . A suitable biased airflow may be also maintained when closure of the valve flap 114 is unsealed. [0064] By way of overview, the expiratory port assembly 200 also comprises a locking ring 12 , which cooperates with toothed gripping element 16 and gasket 30 to secure the expiratory interface assembly 200 to the mask expiratory port. [0065] By way of overview, expiratory port interface assembly 200 also comprises housing element 8 having apertures 44 to vent expired gases to atmosphere, a valve flap 114 upstream thereof and compression springs 888 which maintain the one way valve flap 114 in a closed position unless pressure in the expiratory port interface assembly upstream of the valve exceeds the flap opening pressure (normally when the blower is on due to biased airflow and especially during expiration), as dictated by the springs and atmospheric pressure (seen by the valve flap via apertures 44 ). Housing element 8 also comprises flanges 789 which define circumferential slots to retain the locking ring 12 for sliding movement over the surface of toothed gripping element 16 . Housing element 8 also comprises a port 8 a for receiving the conduit 400 and cylindrically shaped receptacles 114 b for seating the compression springs 888 and pins 114 a . Receptacles 114 c (shown in FIG. 6 ) receive pins 114 a on the downstream side of valve seat element 28 . [0066] As shown in FIGS. 8 and 9 , locking ring 1 comprises a ring portion 777 (shown as spanning the longitudinal distance “B” in FIG. 9 ) and two longitudinally extended gripping portions 775 (having a ridged surface that allow these portions to be more securely gripped by the thumb and index finger of an operator when used to perform the last (locking) step in securing the expiratory interface assembly 200 to the mask expiratory port 2 —gripping portions 775 are shown as spanning the longitudinal distance “A” in FIG. 9 ). Gripping portions 775 have beveled portions 779 that are retained by a plurality of annular flanges 789 of housing element 8 . Beveled portions 779 slidably ride in a longitudinal direction under flanges 789 . [0067] As seen in FIGS. 8 , 10 a and 10 b showing the direction in which the expiratory port interface assembly 200 is moved to slidably engage the mask expiratory port 2 , shortened toothless finger-like projections 898 of toothed gripping element 16 define slots 1000 that avoid interference with T-shaped pins 825 (pins that normally support a conventional ‘mask expiratory port cap and drinking port assembly’—not shown) and thereby permit the expiratory port interface assembly 200 to slide fully onto the mask expiratory port 2 . The gasket 30 has corresponding slots 1100 for the same purpose. As best shown in cross-section in FIG. 7 , annular shoulder 990 of valve seat element 28 serves as a contact surface for contacting the most projecting portion of the mask expiratory port 2 to define this fully mounted position which in turn corresponds with the position in which tooth-like projections 770 can be locked behind surface 2 c of the mask expiratory port 2 for securely coupling the expiratory port interface assembly 200 onto the mask expiratory port 2 . [0068] As best seen in FIG. 7 , cylindrical gasket 30 is pressed into a pneumatically efficient interface with mask expiratory port 2 by finger-like projections of gripping element 16 . These finger-like projections are capable of being compressed against the gasket 30 by sliding locking-ring 12 from the an unlocked position ( FIG. 10 a ) in which the surfaces 12 a and 16 a of the locking ring and finger like projections are not are not engaged to exert a compressing cam action against the finger like projections and a second locked position ( FIG. 10 b ) in which the locking ring is longitudinally displaced towards surfaces 16 c of the finger-like projections, these surfaces on the individual finger-like projections collectively defining an annular (the term annular not necessarily implying continuity) ring-retaining lip 700 of the gripping element 16 that projects radially outwardly to retainingly engage abutment surface 12 c of the locking ring 12 . When the ring is moved from the unlocked position into the locked position beveled cam surfaces 12 b and 16 b of the locking ring and finger-like projections, respectively, slide past one another to exert a radial compressive force against the circumferential exterior face 16 a of the finger-like gripping elements to compress them into closer proximity with one another. This in turn applies corresponding compressive forces respectively against corrugated face 30 a of the gasket 30 and face 2 a of the mask expiratory port 2 . In tandem, the radially inwardly projecting tooth-like portions 770 of the finger-like projections move radially inwardly towards a lesser diameter surface 2 d of the mask expiratory port 2 , so as to lock these tooth-like portions behind the retaining surface 2 c of the mask expiratory port 2 . [0069] As shown in FIG. 11 , in a more general aspect the mask interface device 2000 of the invention may comprise an interface with any respiratory device, for example, any device through which air travels that is functional in conditioning air inspired by the wearer of the mask, the interface, for example, being in the form of port 2002 having a threaded portion 2003 for receiving a second filter 1 a fitted with a mating threaded portion 1 b . Fluidic communication is established between the filters via port 2010 in the interface device. The threaded portion 2003 of the device and the cuff 14 may be adapted to create a sealed communication between the filters 1 and 1 a to prevent noxious elements from entering into the gas mask. The term “air” is used broadly throughout to refer to a gas of any composition pertinent to respiratory assistance, comfort or medical treatment.

A mask interface device is provided for a protective mask of the type having a mask filter and a mask expiratory port, the mask expiratory port having an expiratory port valve of the type that is normally closed and openable upon expiration, the mask filter having an inspiratory air inlet, the mask interface device comprising: a mask interface assembly mountable to the mask and having a mounting interface for mounting an air pressure generator in fluid communication with the inspiratory inlet of the mask filter; and an expiratory port interface assembly mountable to the mask expiratory port and comprising at least one opening for venting expired gas to atmosphere and a one-way valve that is positioned to control the flow of expired gas out through the at least one opening, and wherein the one-way valve is set to an opening pressure that provides positive end expiratory pressure or PEEP. Optionally, this opening pressure is between 2.5 and 20 cm H2O. Optionally, the mask interface device interface directly with the mask filter. In one embodiment of the invention, this interface does not require the filter to have a mating connection and is therefore is universal for a broad class of filters, for example cylindrical filters that project from the mask.

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application is a continuation of U.S. patent application Ser. No. 13/954,735, filed on Jul. 30, 2013, titled “DEVICES AND METHODS FOR CERVIX MEASUREMENT,” now U.S. Pat. No. 8,870,794, which is a continuation of U.S. patent application Ser. No. 13/747,331, filed on Jan. 22, 2013, titled “DEVICES AND METHODS FOR THE CERVIX MEASUREMENT,” now U.S. Pat. No. 8,517,960, which is a continuation of U.S. patent application Ser. No. 12/944,580, filed on Nov. 11, 2010, titled “DEVICES AND METHODS FOR CERVIX MEASUREMENT,” now U.S. Pat. No. 8,366,640, which claims priority to U.S. Provisional Patent Application No. 61/260,520, filed Nov. 12, 2009, entitled “DEVICES AND METHODS FOR CERVIX MEASUREMENT” and U.S. Provisional Patent Application No. 61/369,523, filed Jul. 30, 2010, titled “DEVICES AND METHODS FOR CERVIX MEASUREMENT.” These applications are herein incorporated by reference in their entirety. INCORPORATION BY REFERENCE [0002] All publications and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference. FIELD [0003] The present invention relates to medical devices and methods of using such devices. More particularly, the invention relates to instruments and methods to measure the length of the cervix in the fornix vaginae and the dilation of the cervix uteri. BACKGROUND [0004] Preterm labor, or labor before 37 weeks gestation, has been reported in approximately 12.8 percent of all births but accounts for more than 85 percent of all perinatal complications and death. Rush et al., BMJ 2:965-8 (1976) and Villar et al., Res. Clin. Forums 16:9-33 (1994), which are both incorporated herein by reference. An inverse relationship between cervical length in the fornix vaginae and the risk of preterm labor has also been observed. Andersen et al., Am. J. Obstet. Gynecol. 163:859 (1990); Jams et al., N. Eng. J. Med. 334:567-72 (1996) and Heath et al., and Ultrasound Obstet. Gynecol. 12:312-7 (1998), which all are incorporated herein by reference. Accordingly, many physicians find it useful to examine the cervix in the fornix vaginae as part of normal prenatal care in order to assess risk of preterm labor. [0005] It has long been known that the cervix normally undergoes a series of physical and biochemical changes during the course of pregnancy, which enhance the ease and safety of the birthing process for the mother and baby. For example, in the early stages of labor the tissues of the cervical canal soften and become more pliable, the cervix shortens (effaces), and the diameter of the proximal end of the cervical canal begins to increase at the internal os. As labor progresses, growth of the cervical diameter propagates to the distal end of the cervical canal, toward the external os. In the final stages of labor, the external os dilates allowing for the unobstructed passage of the fetus. [0006] In addition to the physical and biochemical changes associated with normal labor, genetic or environmental factors, such as medical illness or infection, stress, malnutrition, chronic deprivation and certain chemicals or drugs can cause changes in the cervix. For example, it is well known that the in utero exposure of some women to diethylstilbestrol (DES) results in cervical abnormalities and in some cases gross anatomical changes, which leads to an incompetent cervix where the cervix matures, softens and painlessly dilates without apparent uterine contractions. An incompetent cervix can also occur where there is a history of cervical injury, as in a previous traumatic delivery, or as a result of induced abortion if the cervix is forcibly dilated to large diameters. Details of the incompetent cervix are discussed in Sonek, et al., Preterm Birth, Causes, Prevention and Management, Second Edition, McGraw-Hill, Inc., (1993), Chapter 5, which is incorporated by reference herein. [0007] Cervical incompetence is a well recognized clinical problem. Several investigators have reported evidence of increased internal cervical os diameter as being consistent with cervical incompetence (see Brook et al., J. Obstet. Gynecol. 88:640 (1981); Michaels et al., Am. J. Obstet. Gynecol. 154:537 (1986); Sarti et al., Radiology 130:417 (1979); and Vaalamo et al., Acta Obstet. Gynecol. Scan 62:19 (1983), all of which are incorporated by reference herein). Internal os diameters ranging between 15 mm to 23 mm have been observed in connection with an incompetent cervix. Accordingly, a critical assessment in the diagnosis of an incompetent cervix involves measurement of the internal cervical os diameter. [0008] There are also devices and methods to measure the diameter of the external cervical os. For example, cervical diameter can be manually estimated by a practitioner's use of his or her digits. Although an individual practitioner can achieve acceptable repeatability using this method, there is a significant variation between practitioners due to the subjective nature of the procedure. To address these concerns, various monitoring and measuring devices and methods have been developed. For example, an instrument for measuring dilation of the cervix uteri is described in U.S. Pat. No. 5,658,295. However, this device is somewhat large, leading to a risk of injury to the fundus of the vagina or cervical os. Additionally, it is not disposable and requires repeated sterilization. Another device for measuring cervical diameter is described, for example, in U.S. Pat. No. 6,039,701. In one version, the device described therein has a loop element which is secured to the cervix. The loop expands or contracts with the cervix and a gauge is coupled to the loop for measuring changes in the loop dimension. Such changes can then be detected by electronic means. Accordingly, this device is rather complex and expensive to manufacture. [0009] Even if a woman is found to have an apparently normal internal cervical os diameter, there may nonetheless be a risk for preterm labor and delivery. Currently, risk assessment for preterm delivery remains difficult, particularly among women with no history of preterm birth. However, the findings that preterm delivery is more common among women with premature cervical shortening or effacement suggest that a measuring the length of the cervix would be predictive for preterm labor. [0010] Currently, a physician has at least two options to measure the length of the cervix in the fornix vaginae. One such method involves serial digital examination of the cervix by estimating the length from the external cervical os to the cervical-uterine junction, as palpated through the vaginal fornix. Although this is useful for general qualitative analysis, it does not afford an easy nor accurate measurement of the length of the cervix from the external cervical os to the cervical-uterine junction (also described herein as the length of the cervix extending into the vagina) and, therefore, does not provide an accurate assessment of the risk of preterm labor. Despite the use of gloves, digital vaginal exams always carry with them the risk of transmitting infectious agents, especially to the fetal membranes, the lining and/or muscle of the uterus, or to the fetus itself. [0011] Another method involves real-time sonographic evaluation of the cervix. This method provides relatively quick and accurate cervical dimensions. However, it requires expensive equipment, highly skilled operators, as well as skill in interpretation of results, which are all subject to human error. Additionally, there is a risk that the probe that must be inserted into the vagina as part of the procedure may cause injury if not inserted with care. Also, due to the expense of the procedure many women, especially those without proper health insurance, cannot afford to have a sonographic test performed. [0012] It would be beneficial if there were an instrument a practitioner could use to measure the cervix quickly and accurately, and with little material expense. Although there are several instruments available for determining various dimensions of the uterus, there is no suitable instrument for measuring the length of the cervix in the fornix vaginae. For example, U.S. Pat. No. 4,016,867 describes a uterine caliper and depth gauge for taking a variety of uterine measurements, which although useful for fitting an intrauterine contraceptive device, is not capable of measuring the length of the cervix in the fornix vaginae due to interference by the caliper's wings. In fact, similar devices described in U.S. Pat. Nos. 4,224,951; 4,489,732; 4,685,474; and 5,658,295 suffer from similar problems due to their use of expandable wings or divergeable probe tips. These devices are also relatively sophisticated, making them expensive to manufacture and purchase. U.S. Pat. No. 3,630,190 describes a flexible intrauterine probe, which is particularly adapted to measuring the distance between the cervical os and the fundus of the uterus. The stem portion of the device has a plurality of annular ridges spaced apart from each other by a predetermined distance, preferably not more than one-half inch apart. However, this device is not adapted for accurately measuring the length of the cervix in the fornix vaginae because of the lack of an appropriate measuring scale and a stop for automatically recording the measurement. [0013] There exists a need for a simple and inexpensive device that can be used to determine the length of the cervix in the fornix vaginae and, thus, predict the risk of preterm labor, as well as other conditions. There is also a need for such a device that can measure the dilation of the cervix uteri, to provide an overall assessment of the cervix and to determine the particular stage of labor. Ideally, the device should be adapted for use by a physician or obstetrician or even a trained nurse in the doctor's office or clinic. Preferably, the device should be sterile and disposable. In addition, it is desirable that device be able to lock after a measurement is taken to ensure that the measurement does not change between the time a user takes the measurement and removes the device from the patient to read the measurement. The present invention satisfies these needs and provides related advantages as well. SUMMARY OF THE DISCLOSURE [0014] In general, in one aspect, a device for measuring a length of a cervix includes an elongate measurement member, a hollow member, a flange, a handle, and a locking mechanism. The elongate measurement member extends along a longitudinal axis and includes a measurement scale thereon. The hollow member is coaxial with and disposed over the elongate measurement member. The flange is offset from the longitudinal axis and attached to a distal end of the hollow member. The handle is attached to a proximal end of the measurement member. The locking mechanism is configured, when locked, to fix the hollow member relative to the measurement member and, when unlocked to allow the hollow member to slide along the measurement member and rotate about the longitudinal axis so as to place the flange in a desired position without moving the measurement scale. [0015] This and other embodiments can include one or more of the following features. The proximal end of the hollow member can be slideable into the handle. The flange can have an opening through which the measurement member can advance distally. The flange can have a flat surface perpendicular to the longitudinal axis. The locking mechanism can include a button, the button including a through-hole configured such that the hollow member can slide therethrough and a lock channel configured such that the hollow member cannot slide therethrough. The button can further include at least one lock ramp between the through-hole and the lock channel. The measurement scale can be a millimeter scale. The measurement scale can extend from 0 mm to 50 mm. The hollow member can be transparent. The measurement scale can include an opaque background. The device can further include an indicator line on the hollow member. The indicator line can be a color other than black. [0016] In general, in one aspect, a method for measuring a length of a cervix includes: holding a handle of a device, the device further including an elongate measurement member having a measurement scale thereon, a hollow member coaxial with and disposed over the elongate measurement member, and a flange attached to a distal end of the hollow member; rotating the hollow member about the elongate measurement member so as to place the flange at a desired orientation without rotating the measurement scale; advancing the device distally within a vagina until the flange contacts a cervix at an external uterine opening; advancing the measurement member distally within the vagina until a distal end of the measurement member contacts a cervical uterine junction at a fornix vaginae; locking the measurement member relative to the hollow member by locking a locking mechanism on the handle; and observing a position of the hollow member with respect to the measurement member to determine a length of the cervix in the fornix vaginae. [0017] This and other embodiments can include one or more of the following features. Advancing the measurement member distally can include sliding the hollow member into the handle. The flange can be offset from a longitudinal axis of the measurement member. The locking mechanism can include a button having a through-hole and a lock channel, and wherein locking the locking mechanism comprises pushing the button such that the hollow member moves into the lock channel and cannot slide through the through-hole. Observing the position can include observing an indicator line on the hollow member with respect to a measurement scale on the measurement member. The method can further include determining the risk of miscarriage based upon the length of the cervix in the fornix vaginae, wherein the length of the cervix in the fornix vaginae is inversely related to the risk of miscarriage. The method can further include predicting the ease of inducing labor, wherein the length of the cervix in the fornix vaginae is inversely related to the ease of inducing labor. The method can further include determining the risk of preterm labor based upon the length of the cervix in the fornix vaginae, wherein the length of the cervix in the fornix vaginae is inversely related to the risk of preterm labor. BRIEF DESCRIPTION OF THE DRAWINGS [0018] The novel features of the invention are set forth with particularity in the claims that follow. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which: [0019] FIG. 1 a is an illustration of a measuring device, according to one embodiment. [0020] FIGS. 1 b - 1 e are additional views of the measuring device of FIG. 1 a. [0021] FIG. 2 a is an illustration of a measuring device, according to one embodiment. [0022] FIGS. 2 b - 2 e are additional views of the measuring device of FIG. 2 a. [0023] FIG. 3 a is an illustration of a measuring device, according to one embodiment. [0024] FIGS. 3 b - 3 d are additional views of the measuring device of FIG. 3 a. [0025] FIG. 4 a is an illustration of a measuring device, according to one embodiment. [0026] FIGS. 4 b - 4 g are additional views of the measuring device of FIG. 4 a. [0027] FIG. 5 a is an illustration of a measuring device, according to one embodiment. [0028] FIGS. 5 b - 5 d are additional views of the measuring device of FIG. 5 a. [0029] FIG. 6 a is an illustration of a measuring device, according to one embodiment. [0030] FIGS. 6 b - 6 f are additional views of the measuring device of FIG. 6 a. [0031] FIG. 7 a is an illustration of a measuring device, according to one embodiment. [0032] FIGS. 7 b - 7 h are additional views of the measuring device of FIG. 7 a. [0033] FIG. 8 is an illustration of a measuring device in use for measuring the vaginal cervix. DETAILED DESCRIPTION [0034] The present invention provides various devices and methods for determining dimensions of female reproductive organs. For example, the devices described herein are particularly adapted for determining the length of the cervix in the fornix vaginae, which, as described above, is related to the risk of preterm labor in an individual. The devices can also be suited for determining the dilation of the cervix uteri, for predicting the risk of preterm labor or the particular stage of delivery. [0035] It is, however, contemplated herein, that the invention is not limited to determining various dimensions of female reproductive organs. For example, the invention can be usable for determining the dimension of any body cavity or passageway where such a device would be insertable, such as a vagina, uterus, mouth, throat, nasal cavity, ear channel, rectum, and also to any cavity created and opened by surgery, for example, during chest, abdominal or brain surgery. [0036] The devices described herein are also preferably fabricated from relatively inexpensive materials and the measurement is quick to perform. This allows the practitioner to repeat the test over time and therefore to more closely monitor a woman's pregnancy and risk for preterm labor. It is also contemplated that the device can record the various measurements automatically, where the only input required by the practitioner is the proper insertion of the device into the body cavity or passageway. This can be accomplished by the use of a flange to stop progression of the hollow member of the device while still allowing the measurement member to be advanced within the body. [0037] FIG. 1 a illustrates a measuring device 100 that includes an elongated measurement member 102 and an elongated hollow member 104 . The elongated measurement member 102 is adapted to be inserted into the hollow member 104 , and specifically into a lumen of the hollow member. Handle 106 can be positioned on a proximal portion of the measuring device, as shown in FIG. 1 a . In one embodiment, the handle is molded from the same material as the measurement member 102 . In other embodiments, the handle can be a rubber or foam component that is fitted on to and over the proximal end of the measuring device. [0038] A measurement scale 108 can be disposed along a portion of the measurement member 102 . The measurement scale 108 can include any number of a series of visual markings on the measurement member 102 which relate a measurement or distance. In a particularly preferred embodiment, the measurement scale 108 includes a plurality of millimeter (mm) incremental markings and a plurality of centimeter (cm) incremental markings. [0039] As shown in FIG. 1 a , the measurement scale 108 can be color-coded to indicate the relative risks of preterm delivery for a cervix length falling within each respective colored region. For example, in one embodiment, a first zone 132 can include the incremental markings less than 2 cm and can be coded in a first color, such as red, a second zone 134 can include the incremental markings from 2 to 3 cm and can be coded in a second color, such as yellow, and the third zone 134 can include the incremental markings from 3 to 5 cm and can be coded in a third color, such as green. In FIG. 1 a , the measurement scale is color-coded into three regions that each visually represents the relative risks of preterm delivery for a cervix length falling within the respective region. For instance, the first zone 132 indicates a shorter cervix, and therefore a higher risk of preterm delivery, than the second zone 134 , which indicates a cervix length that reflects a higher risk of preterm delivery than the green zone 136 . [0040] A flange 110 that is shaped for non-abrasive contact with tissue can be disposed on a distal portion of measuring device 100 . The flange can be preferably flat and spherically or conically shaped. Alternatively, however, the flange may be any other non-abrasive shape to reduce irritation and scraping of the cervical canal, fundus of the vagina or perforation of the fundus of the uterus. The main body of the flange is also preferably offset from the longitudinal axis of the measuring device 100 . Additionally, the flange can include an opening 112 through, which measurement member 102 may be advanced distally after the flange contacts a bodily surface. Preferably, the flange is secured to the distal end of the hollow member 104 using a suitable attachment means, such as, e.g., an adhesive. Alternatively, the flange may be formed as an integral component of the hollow member 104 . [0041] FIGS. 1 b - 1 d illustrate the operation of the measuring device 100 as it is used to measure the length of a cervix. When the distal end of the measurement member 102 is flush with the flange, as shown in FIG. 1 b , the device is in a starting configuration. The device 100 can be advanced into the vagina until the flange 110 is placed into contact with the end of the cervix at the external uterine opening. At this point, further forward progress of the hollow member 104 within the cervical canal or further within the body is prevented as a result of the contact between flange 110 and the end of the cervix at the external uterine opening. Since flange 110 is preferably offset from the longitudinal axis of measuring device 100 , in one embodiment the flange is placed both in contact with the end of the cervix and also covering the external uterine opening. As a result, the device can oriented so that measurement member 102 is still able to be progressed within the fornix, rather than being advanced through the uterus, since the body of flange 106 is, with this method, covering the external uterine opening. [0042] Subsequently, as shown in FIGS. 1 c - 1 d , a distal portion of measurement member 102 can continue to be advanced through opening 112 of flange 110 until the distal end contacts a wall of the body, such as, e.g., the anterior fornix. When the distal end of the measurement member is advanced beyond the flange the device is in a measuring configuration. FIG. 1 c shows a side view of the measurement member in the measuring configuration, and FIG. 1 d shows a top down view of the device in the measuring configuration. It can be seen in FIG. 1 d , for example, that the measurement member has been advanced 4 cm beyond the flange. The length of the cervix can then be measured by observing the position of the proximal end of the hollow member 104 along the measurement scale 108 of the measurement member 102 . In another embodiment, a method of measurement comprises advancing the distal end of the measurement member 102 to the wall of the body, such as the anterior fornix, and then advancing the hollow member 104 so that the flange 110 is placed into contact with the end of the cervix at the external uterine opening. [0043] Referring now to FIG. 1 e , a locking mechanism 114 can be located on the measuring device 100 that allows a user to secure the measurement member 102 within the hollow member 104 after the measurement of a body part, such as, e.g., the length of the cervix. In FIG. 1 e , the locking mechanism 114 includes button 116 , cantilever arm 118 , detents 120 , and opening 122 . When the locking mechanism is in the locked configuration, as shown in FIG. 1 e , the cantilever arm 118 engages detents 120 on the inside of hollow member 104 . The cantilever arm can be integral to the measurement member 102 , for example. To allow sliding of the measurement member within the hollow member, button 116 can be pressed inwards towards opening 122 , causing cantilever arm 118 to disengage detents 120 and allow sliding. [0044] For example, to take a measurement of a body part, a user can insert the measuring device 100 into the patient. The user can then press the button 116 inwards to disengage the cantilever arm and allow the measurement member to slide within the hollow member. After the measurement of a body part is taken with the device, the user can release the button, causing the cantilever arm to engage the detents and lock the position of the measurement member 102 within the hollow member 104 . This allows the user to remove the device from the patient to read the measurement scale while ensuring that movement of the measurement member 102 proximally or distally within the hollow member 104 is prevented. [0045] During a measurement procedure, a user can hold handle 106 with the dominant hand like a dart, and can hold the barrel of the hollow member 104 with the non-dominant hand. The user can activate button 116 with the dominant hand to temporarily unlock the measuring device, allowing the hollow member to slide with respect to the measurement member. [0046] Referring now to FIG. 2 a , another embodiment of a measuring device 200 is shown. Measuring device 200 includes many of the features of measuring device 100 , described above and illustrated in FIGS. 1 a - 1 e . For example, measuring device 200 includes an elongated measurement member 202 slidably disposed within an elongated hollow member 204 . Handle 206 can be positioned on a proximal portion of the measuring device, and measurement scale 208 , such as a color-coded measurement scale, can be disposed on the measurement member 202 . The measuring device can further include a flange 210 on a distal portion of the device, and an opening 212 that allows the measurement member 202 to extend distally beyond the hollow member 204 . [0047] As described above, the device 200 can have a starting configuration, as shown in FIG. 2 b , and a measuring configuration, as shown in FIG. 2 c . The measuring device 200 can further include a locking mechanism 214 . The locking mechanism allows a user to lock the measurement member 202 within the hollow member 204 , to prevent movement of the measurement member with respect to the hollow member after a measurement is taken. In the embodiment shown in FIGS. 2 a - 2 e, the locking mechanism 214 is disposed on the hollow member 204 . [0048] Referring now to FIG. 2 d , which is a side view of the locking mechanism 214 , and FIG. 2 e , which is a cross sectional view of the locking mechanism 214 , the locking mechanism can further include pads or buttons 216 , tabs 218 , and detents 220 . The buttons 216 and tabs 218 can be integral to the hollow member 204 , and the detents 220 can be integral to the measurement member 202 , for example. In the embodiment shown in FIGS. 2 d - 2 e, the locking mechanism includes two buttons 216 . However, in other embodiments, the locking mechanism can include only a single button, or alternatively, can include more than two buttons. [0049] When the locking mechanism 214 is in a locked configuration, as shown in FIG. 2 d , the tabs engage detents 220 , preventing any movement of the measurement member with respect to the hollow member 204 . However, when the buttons 216 are depressed inwards by a user, as shown in FIG. 2 e , the tabs 218 can be squeezed outwards, as indicated by arrows 224 , causing them to disengage from detents 220 . This allows a measurement to be taken by sliding the measurement member 202 within the hollow member 204 . [0050] To take a measurement of a body part, a user can insert the measuring device 200 into the patient. The user can then press the button or buttons 216 inwards to cause the tabs 218 to squeeze outwards disengaging detents 220 , thereby allowing the measurement member to slide within the hollow member. After the measurement of a body part is taken with the device, the user can release the buttons, causing the tabs to engage the detents and lock the position of the measurement member 202 within the hollow member 204 . This allows the user to remove the device from the patient to read the measurement scale while ensuring that movement of the measurement member 202 proximally or distally within the hollow member 204 is prevented. [0051] During a measurement procedure, a user can hold handle 206 with the dominant hand like a dart, and can hold the barrel of the hollow member 204 with the non-dominant hand. The user can activate button 216 with the non-dominant hand to temporarily unlock the measuring device, allowing the hollow member to slide with respect to the measurement member. [0052] Referring now to FIG. 3 a , yet another embodiment of a measuring device 300 is shown. Measuring device 300 includes many of the features of measuring device 100 , described above and illustrated in FIGS. 1 a - 1 e . For example, measuring device 300 includes an elongated measurement member 302 slidably disposed within an elongated hollow member 304 . Handle 306 can be positioned on a proximal portion of the measuring device, and measurement scale 308 , such as a color-coded measurement scale, can be disposed on the measurement member 302 . The measuring device can further include a flange 310 on a distal portion of the device, and an opening 312 that allows the measurement member 302 to extend distally beyond the hollow member 304 . [0053] As described above, the device 300 can have a starting configuration, as shown in FIG. 3 b , and a measuring configuration, as shown in FIG. 3 c . In addition, a locking mechanism 314 can be located on the measuring device 300 that allows a user to secure the measurement member 302 within the hollow member 304 after the measurement of a body part, such as, e.g., the length of the cervix. [0054] In FIG. 3 d , the locking mechanism 314 includes button 316 , cantilever arm 318 , and detents 320 . When the locking mechanism is in the locked configuration, as shown in FIG. 3 d , the cantilever arm 318 engages detents 320 on the outside of measurement member 302 . The cantilever arm can be integral to the hollow member 304 , for example. To allow sliding of the measurement member within the hollow member, button 316 can be pressed inwards, causing cantilever arm 318 to disengage detents 320 and allow sliding. [0055] For example, to take a measurement of a body part, a user can insert the measuring device 300 into the patient. The user can then press the button 316 inwards to disengage the cantilever arm and allow the measurement member to slide within the hollow member. After the measurement of a body part is taken with the device, the user can release the button, causing the cantilever arm to engage the detents and lock the position of the measurement member 302 within the hollow member 304 . This allows the user to remove the device from the patient to read the measurement scale while ensuring that movement of the measurement member 302 proximally or distally within the hollow member 304 is prevented. [0056] During a measurement procedure, a user can hold handle 306 with the dominant hand like a dart, and can hold the barrel of the hollow member 304 with the non-dominant hand. The user can activate button 316 with the non-dominant hand to temporarily unlock the measuring device, allowing the hollow member to slide with respect to the measurement member. [0057] Referring now to FIG. 4 a , another embodiment of a measuring device 400 is shown. Measuring device 400 includes many of the features of measuring device 100 , described above and illustrated in FIGS. 1 a - 1 e . For example, measuring device 400 includes an elongated measurement member 402 slidably disposed within an elongated hollow member 404 . Handle 406 can be positioned on a proximal portion of the measuring device, and measurement scale 408 , such as a color-coded measurement scale, can be disposed on the measurement member 402 . The measuring device can further include a flange 410 on a distal portion of the device, and an opening 412 that allows the measurement member 402 to extend distally beyond the hollow member 404 . [0058] As described above, the device 400 can have a starting configuration, as shown in FIG. 4 b , and a measuring configuration, as shown in FIG. 4 c . In contrast to the embodiments described above, the hollow member 404 of the measuring device 400 in FIGS. 4 a - 4 e slides into the handle 406 when a measurement is taken. The measurement member 402 remains fixed in position with respect to the handle, which allows the measurement member to extend distally beyond the flange 410 during measurements. [0059] The measuring device 400 can further include a locking mechanism 414 . The locking mechanism allows a user to lock the hollow member 404 within the handle 406 , to prevent movement of the hollow member with respect to the measurement member after a measurement is taken. In the embodiment shown in FIGS. 4 a - 4 e, the locking mechanism 414 can comprise a button 416 with a through-hole (not shown). In FIG. 4 d , the device is shown in an unlocked configuration, in which the through-hole is aligned with the hollow member 404 to allow the hollow member to travel therethrough. When the device is in a locked configuration, as shown in FIG. 4 e , the through-hole pushes against the hollow member, preventing movement of the hollow member with respect to the measurement member. [0060] FIG. 4 f shows a cross-sectional view of locking mechanism 414 , button 416 , and hollow member 404 . The button geometry is designed to operate smoothly with a low actuation force to engage the locking mechanism. The open channel 418 of the button allows the hollow member 404 to slide freely into the handle when a measurement is being taken. When the button is depressed, the lock ramps 420 are forced to slide over the hollow member 404 , which provides tactile and audible feedback that the device is in the locked position. The design of the lock ramps, including height and ramp angle affects the effort levels required to activate the button. The width of the lock channel 422 is designed to be narrower than the overall outside diameter of the hollow member 404 , so that the interference between the two surfaces provides a retention force to maintain the measurement while the device is removed from the patient. In some embodiments, the locking mechanism does not include the lock ramps 420 . In other embodiments, the lock channel 422 can be tapered to provide a frictional, locking fit for hollow member 404 when button 416 is depressed, as shown in FIG. 4 g. [0061] For example, to take a measurement of a body part, a user can insert the measuring device 400 in an unlocked configuration (e.g., where the through-hole is aligned to allowed movement of the hollow member) into the patient. After the measurement of a body part is taken with the device, the user can press the button 416 , causing the through-hole to press against the hollow member to prevent movement of the hollow member. This allows the user to remove the device from the patient to read the measurement scale while ensuring that movement of the measurement member 402 proximally or distally within the hollow member 404 is prevented. [0062] During a measurement procedure, a user can hold handle 406 with the dominant hand like a dart, and can hold the barrel of the hollow member 104 with the non-dominant hand. After taking a measurement, the user can activate button 416 with the dominant hand to lock the measuring device, preventing the hollow member from sliding with respect to the measurement member. [0063] Referring now to FIG. 5 a , another embodiment of a measuring device 500 is shown. Measuring device 500 includes many of the features of measuring device 100 , described above and illustrated in FIGS. 1 a - 1 e . For example, measuring device 500 includes an elongated measurement member 502 slidably disposed within an elongated hollow member 504 . Syringe-style handle 506 can be positioned on a proximal portion of the measuring device, and measurement scale 508 , such as a color-coded measurement scale, can be disposed on the measurement member 502 . The measuring device can further include a flange 510 on a distal portion of the device, and an opening 512 that allows the measurement member 502 to extend distally beyond the hollow member 504 . [0064] As described above, the device 500 can have a starting configuration, as shown in FIG. 5 b , and a measuring configuration, as shown in FIG. 5 c . Similar to the embodiment of measuring device 400 described above and illustrated in FIGS. 4 a - 4 e, the hollow member 504 of the measuring device 500 in FIGS. 5 a - 5 d slides into the handle 506 when a measurement is taken. The measurement member 502 remains fixed in position with respect to the handle, which allows the measurement member to extend distally beyond the flange 510 during measurements. [0065] The measuring device 500 can further include a locking mechanism 514 . The locking mechanism allows a user to lock the hollow member 504 within the handle 506 , to prevent movement of the hollow member with respect to the measurement member after a measurement is taken. In the embodiment shown in FIG. 5 d , the locking mechanism 514 can comprise a button 516 with a through-hole (not shown). Similar to the embodiments described above in FIGS. 4 a - 4 e , the device can have an unlocked configuration, in which the through-hole is aligned with the hollow member 504 to allow the hollow member to travel therethrough. The device can also have a locked configuration, in which the through-hole pushes against the hollow member thereby preventing movement of the hollow member with respect to the measurement member. [0066] To take a measurement of a body part, a user can insert the measuring device 500 in an unlocked configuration (e.g., where the through-hole is aligned to allowed movement of the hollow member) into the patient. After the measurement of a body part is taken with the device, the user can press the button 516 , causing the through-hole to press against the hollow member to prevent movement of the hollow member. This allows the user to remove the device from the patient to read the measurement scale while ensuring that movement of the measurement member 502 proximally or distally within the hollow member 504 is prevented. In FIG. 5 d , the measurement scale is read at point 526 on the handle when taking the measurement, for example. [0067] During a measurement procedure, a user can hold syringe-style handle 506 with the dominant hand like a syringe, and can hold the barrel of the hollow member 504 with the non-dominant hand. After taking a measurement, the user can activate button 516 with the dominant or non-dominant hand to lock the measuring device, preventing the hollow member from sliding with respect to the measurement member. [0068] Referring now to FIG. 6 a , another embodiment of a measuring device 600 is shown. Measuring device 600 includes many of the features of measuring device 100 , described above and illustrated in FIGS. 1 a - 1 e . For example, measuring device 600 includes an elongated measurement member 602 slidably disposed within an elongated hollow member 604 . Handle 606 can be positioned on a proximal portion of the measuring device, and measurement scale 608 , such as a color-coded measurement scale, can be disposed on the measurement member 602 . The measuring device can further include a flange 610 on a distal portion of the device, and an opening 612 that allows the measurement member 602 to extend distally beyond the hollow member 604 . [0069] As described above, the device 600 can have a starting configuration, as shown in FIG. 6 b , and a measuring configuration, as shown in FIG. 6 c . The measuring device 600 can further include a locking mechanism 614 . The locking mechanism allows a user to lock the measurement member 602 within the hollow member 604 , to prevent movement of the measurement member with respect to the hollow member after a measurement is taken. In the embodiment shown in FIGS. 6 a - 6 f, the locking mechanism 614 is disposed on the hollow member 204 . [0070] Referring now to FIG. 6 d , which is a cross sectional view of the locking mechanism 614 , the locking mechanism can further an annular snap 628 . The measurement member 602 also has an annular snap 630 that corresponds to the annular snap 628 on the locking mechanism. When the locking mechanism is in an unlocked configuration, as shown in FIG. 6 d , the annular snaps 628 and 630 are not in contact, so there is some play between the locking mechanism 614 and the measurement member 602 , which allows the measurement member to slide freely within the hollow member 604 . As a user rotates the locking mechanism, as shown in FIG. 6 e , the annular snaps contact each other, providing the user with tactile feedback of locking. In FIG. 6 f , the locking mechanism is shown in a locked configuration, with the annular snaps contacting each other on both sides. When the annular snaps are in contact as shown in FIG. 6 f , there is no play between the hollow member and the measurement member, which prevents movement of the hollow member with respect to the measurement member. [0071] To take a measurement of a body part, a user can insert the measuring device 600 into the patient in the unlocked configuration. After the measurement of a body part is taken with the device, the user can rotate the locking mechanism 614 , causing the annular snaps to engage each other on both sides to lock the position of the measurement member 602 within the hollow member 604 . This allows the user to remove the device from the patient to read the measurement scale while ensuring that movement of the measurement member 602 proximally or distally within the hollow member 604 is prevented. [0072] During a measurement procedure, a user can hold handle 606 with the dominant hand like a dart, and can hold the locking mechanism 614 with the non-dominant hand. After taking a measurement, the user can rotate the locking mechanism with the non-dominant hand until the annular snaps engage each other to lock the measuring device, preventing the hollow member from sliding with respect to the measurement member. The user can also hold steady the locking mechanism 614 with the non-dominant hand and rotate the handle 606 with the dominant hand until the annular snaps engage each other to lock the measuring device. The relative motion of the locking mechanism 614 and the handle 606 is what engages the locking mechanism, regardless of which is held in place and which is rotated. [0073] Referring now to FIG. 7 a , another embodiment of a measuring device 700 is shown. Measuring device 700 includes many of the features of measuring device 100 , described above and illustrated in FIGS. 1 a - 1 e . For example, measuring device 700 includes an elongated measurement member 702 slidably disposed within an elongated hollow member 704 . The measuring device can further include a flange 710 on a distal portion of the elongated hollow member 704 , and an opening 712 that allows the measurement member 702 to extend distally beyond the hollow member 704 . Handle 706 can be positioned on a proximal portion of the measuring device and can be attached to the measurement member and measurement scale 708 can be disposed on the measurement member 702 . As shown in FIG. 7 f , the measurement scale can be a millimeter sale, with markings from 0-50 mm, marked in 5 mm increments. Moreover, the background 732 for the measurement scale 708 can be opaque. For example, the measurement member 702 can be composed of an opaque material or an opaque coating can cover the portion of the measurement member 702 on which the measurement scale 708 is printed. An opaque background for the measurement scale can allow for easier readability of the numbers on the scale. Further, the hollow member 704 can be transparent and include an indicator line 734 that is colored, e.g., blue, to help contrast it from the measurement scale. Contrasting the indicator line 734 with the measurement scale allows for easier readability of the final measurement. [0074] As described above, the device 700 can have a starting configuration, as shown in FIG. 7 b , and a measuring configuration, as shown in FIG. 7 c . Similar to the embodiment of measuring device 400 described above and illustrated in FIGS. 4 a - 4 e, the hollow member 704 of the measuring device 700 in FIGS. 7 a - 7 d slides into the handle 706 (or, alternatively, the handle 706 slides over the hollow member 704 ) when a measurement is taken. The measurement member 702 remains fixed in position with respect to the handle, which allows the measurement member to extend distally beyond the flange 710 during measurements. As shown in FIGS. 7 g and 7 h , the elongated hollow member 704 can be free to rotate with respect to the handle 706 and the measurement member 702 ( FIG. 7 g shows the flange 710 extending parallel to the page, while FIG. 7 h shows the flange 710 extending out of the page). Such free rotation allows for the accommodation of any measurement technique, e.g. right or left-handed measurements, while still allowing for proper placement of the flange 710 . That is, rotation of the hollow member 702 to place the flange 710 in a desired position allows the measurement scale to remain in place, i.e., facing the user. Maintaining the measurement scale directed towards the users ensures that the user is more easily able to read and determine the measured length. [0075] The measuring device 700 can further include a locking mechanism 714 . The locking mechanism allows a user to lock the hollow member 704 within the handle 706 , to prevent rotational or longitudinal movement of the hollow member with respect to the measurement member after a measurement is taken. In the embodiment shown in FIG. 7 d , the locking mechanism 714 can comprise a button 716 with a through-hole (not shown). Similar to the embodiments described above in FIGS. 4 a - 4 e, the device can have an unlocked configuration, in which the through-hole is aligned with the hollow member 704 to allow the hollow member to travel therethrough. The device can also have a locked configuration, in which the through-hole pushes against the hollow member thereby preventing movement of the hollow member with respect to the measurement member. [0076] To take a measurement of a body part, a user can hold the handle 706 with the dominant hand and can hold the hollow member 704 with the non-dominant hand. The user can orient the measuring scale 708 such that it faces the user and can then rotate the hollow member 704 such that the flange 710 is properly oriented with respect to the patient. Because the hollow member 704 is transparent, the measuring scale 708 can be viewed through the hollow member 704 . [0077] The measuring device 700 can be inserted in an unlocked configuration (e.g., where the through-hole is aligned to allowed movement of the hollow member) into the patient. After the measurement of a body part is taken with the device, as described above, the user can press the button 716 , causing the through-hole to press against the hollow member to prevent movement of the hollow member. This allows the user to remove the device from the patient to better read the measurement scale while ensuring that movement of the measurement member 702 proximally or distally within the hollow member 704 is prevented. [0078] Referring to FIG. 8 , the devices described herein can be used to measure the vaginal cervical length. The flange 810 (representing any of the flanges described herein) can be placed against the proximal wall of cervix 802 , while the measurement member 702 (representing any of the measurement members described herein) can be extended along the lateral wall of the cervix 802 until it is stopped by the vaginal fornix 804 . The measurement member 702 and the flange 810 can then be locked with respect to one another such that the device's measurement scale can be used to determine the length as described above. [0079] As for additional details pertinent to the present invention, materials and manufacturing techniques may be employed as within the level of those with skill in the relevant art. The same may hold true with respect to method-based aspects of the invention in terms of additional acts commonly or logically employed. Also, it is contemplated that any optional feature of the inventive variations described may be set forth and claimed independently, or in combination with any one or more of the features described herein. Likewise, reference to a singular item, includes the possibility that there are plural of the same items present. More specifically, as used herein and in the appended claims, the singular forms “a,” “and,” “said,” and “the” include plural referents unless the context clearly dictates otherwise. It is further noted that the claims may be drafted to exclude any optional element. As such, this statement is intended to serve as antecedent basis for use of such exclusive terminology as “solely,” “only” and the like in connection with the recitation of claim elements, or use of a “negative” limitation. Unless defined otherwise herein, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The breadth of the present invention is not to be limited by the subject specification, but rather only by the plain meaning of the claim terms employed.

A device for measuring a length of a cervix includes an elongate measurement member extending along a longitudinal axis and including a measurement scale thereon, a hollow member coaxial with and disposed over the elongate measurement member, a flange offset from the longitudinal axis and attached to a distal end of the hollow member, a handle attached to a proximal end of the measurement member, and a locking mechanism on the handle. The hollow member is freely rotatable about the longitudinal axis relative to the measurement member to place the flange in a first position and in a second position perpendicular to the first position without moving the measurement scale. The locking mechanism is configured, when locked, to fix the hollow member relative to the measurement member and, when unlocked, to allow the hollow member to slide axially along the measurement member in the first and second positions.

FIELD OF THE INVENTION [0001] The present invention relates to containers for containing products that are sensitive to radiation, especially light, essentially of the food industry, more particularly milk and further dairy products, including nutrients and dairy products that are enriched or contain fruit. [0002] The present invention also relates to a preform, serving as a semi-finished product, for making such containers, consisting of at least one base layer made of is a primary plastic material, with a certain amount of additives incorporated in it. BACKGROUND OF THE INVENTION [0003] Plastic containers including bottles made of polyesters and notably polyethylene terephthalate (PET) are increasingly employed for packaging food and drinks. PET containers were originally used for carbonated beverages, such as soda water. They have since gained considerable ground in all areas of the food sector, such as drinks, including milk. [0004] Polyethylene terephthalate is an excellent material for packaging pasteurized milk, which does not keep for long and is distributed and kept cold, with a shelf life of 7-10 days. However, the absence of a built-in light barrier extending across the whole container greatly hampers the use of all-PET plastic formulations for packaging sterilized, long-life ultra-high temperature (UHT) milk, which keeps for 4-6 months at a normal temperature. [0005] One of the problems with milk and dairy products generally lies in their unstable nature. The fact is that they can be attacked by undesirable external effects forming part of the prevailing conditions of the surroundings. Their keeping properties therefore depend to a great extent on the way they are packed. [0006] Owing to the absence of protection from light in the existing packaging units, the milk in them undergoes photo-oxidation. This causes undesirable off-flavours associated with the action of light, Riboflavin (vitamin B 2 ) is also readily attacked, and so are some of the other vitamins and nutrients, which similarly undergo photo-degradation in the presence of light. [0007] It is well known that milk is degraded by exposure to visible but also invisible light, mainly in the wavelength range between 200 and 550 nm. It must therefore be protected at all cost from harmful light of such wavelengths in order to ensure that the quality of milk is retained for the entire shelf life scheduled for it. [0008] In the case of products containing additional nutrients that are sensitive to oxygen, the penetration of the latter must also be reduced as much as possible in order to stop the deterioration of the quality. Packs have therefore been developed for UHT milk to prevent the penetration both of visible light and of UV radiation. Multilayer carton packs with a full light barrier have thus been introduced, as well as aluminium foil to prevent the penetration of oxygen. However, the keeping qualities of the contents of these packs after opening leave something to be desired, owing to the closure of these packaging units. PRIOR ART [0009] The Japanese document JP 55 117632 A of MITSUBISHI RAYON describes a plastic container with a transparent neck and an opaque body, so that not all its parts have the same opacity, and the light barrier is not present over the whole container, i.e. it does not extend over the neck section. Furthermore, these containers are only intended for cosmetics. [0010] The European Patent Application EP 0 273 681 A2 of MOBIL OIL CORP describes a process for making polymer films that become glossy when incorporating high percentages of additives up to 30%, to ensure the required opacity in the end product, but they do not have a definite three-dimensional shape and actually do not even have a shape of their own at all. In addition, the additive concentration in them is quite high. It is also stressed here that the additive must have a higher glass transition temperature T g and a higher melting temperature T m than the base polymer used as the primary material, which is a set precondition for being able to keep the mixture in the molten state. This is of course a significant limitation, since the material must inevitably be melted during its processing. Besides, this document does not give any information about the specificity connected with the well-defined three-dimensional shape of the object envisaged here. [0011] The American patent U.S. Pat. No. 4,410,482 A of SUBRAMANIAN PALLATHERI yet describes extruded and blown bottles made from mixtures of polymers, but again high percentages, up to 40% of additives are used in them, i.e. even more than in the case depicted above. [0012] The European Patent Application EP 0 974 438 A1 of TEIJIN Ltd yet describes polymer mixtures, but they are intended for transparent containers, whose light-barrier properties appear to be unsatisfactory, or at least call for considerable improvement. [0013] The European Patent Application EP 0 273 897 A2 of MONSANTO EUROPE S.A. describes aerosol-type pressurized containers made from non-opaque preforms that consist of mixtures of PET and additives of the type of styrene-maleic anhydride (SMA) copolymer, yet with a still high concentration of the latter up to 30%. The purpose of this additive is mainly to make the resulting PET containers more rigid, so that they are able to fairly resist the high pressures used in aerosol-type containers envisaged here. However, this document does not contribute to solve the present problem about the improvement of the walls of the packs for excluding the incident light, which in case of ordinary containers are characterised by a proper shape under normal atmospheric pressure of about 1 atm. Nor does this document describe an opaque preform. AIM OF THE INVENTION [0014] The aim of the present invention is to solve the problem mentioned above by including additives that are easier to manage and are more suitable, as regards both their nature and amount, in the primary base material under the abovementioned normal conditions of use, mainly pressure but also to some extent temperature, notably under the atmospheric conditions of the surroundings. SUMMARY OF THE INVENTION [0015] There is thus proposed in the present invention a preform, which is remarkable in that it is opaque and consists of a primary plastic material and a low percentage of additives to ensure a whitish opaque appearance over virtually the whole preform. Thanks to the preform proposed according to the invention, an opaque container such as a bottle can be directly obtained that reliably protects its contents from external radiation, especially electromagnetic radiation and more specifically light, whether natural or artificial and whether visible or ultraviolet. It will be understood that we are dealing here with ordinary containers that have stiff or semi-rigid walls of a predetermined shape and which do not have to meet special requirements such as those needed for high pressure. The containers proposed according to the invention are yet intended for use at normal pressure. Opaque preforms are thus proposed which serve as semi-finished intermediate products that can be easily and directly converted into containers that have efficient light barrier properties. In particular, the refractive index of the primary base material is modified here to such an extent that the incident radiation suffers virtually no refraction. As a result, the drink or food kept in the container is protected from harmful external light under normal operating conditions as regards pressure, especially against photo-oxidation and from the subsequent degradation of products occurring under the influence of photo-catalysis. [0016] In a preferred embodiment of the present invention, the plastic is PET. This choice of material has several advantages indeed in the applications that are relevant to the invention, including a great flexibility of designing and shaping the container and a more reliable formation of the neck region of it, which makes it possible to drink straight out of the bottle without any problems. [0017] In a particular embodiment of the present invention, the additives used are polymeric substances. As a result, the containers can be made with a nacreous effect, which ensures that a large part of the incident light is automatically reflected by its surface. In addition, the walls of the container have a large measure of internal refraction. These two phenomena—reflection and refraction—jointly ensure a considerable barrier to the penetration of light, which is desirable in the case of light-sensitive products such as UHT milk. The latter can therefore be kept reliably over long periods even under normal conditions, i.e. at room temperature and in the presence of light, without needing special storage conditions, such as a dark or cool place. A significant improvement is thus achieved over the existing PET structures, because the former are particularly suitable for keeping the products at a normal temperature, which is especially advantageous in the case of containers used for packaging UHT milk, which are kept at room temperature. Another advantage is that the well-known white pigment, which is more expensive, can be replaced by a low percentage of cheaper polymeric additives, which reduces the cost. [0018] In a specific embodiment of the present invention, the additives are thermoplastic polymers. An excellent opacity may be achieved in the outside wall of the preform in this way, and the base material, generally PET, has a higher T g and T m value than the additive admixed to it. [0019] In a further embodiment of the present invention, the additives are polyolefins. The advantage thereof is that this material is incompatible with the primary base material (PET), their refractive indices being very different from that of PET. When two polymers with different refractive indices are mixed together, they produce a white mixture. [0020] In a preferred embodiment of the present invention, said additive is polypropylene (PP). Indeed, this material is easy to disperse, especially in PET, which makes it useful when converting the preform into the container. [0021] The present invention makes it possible to obtain a satisfactory opacity in the outer wall by admixing the above thermoplastic polymeric additives to PET in a ratio of 1:10 in terms of percent by weight. The remarkable thing is that the change to white occurs already with a very little additive of up to only 2%, which is far less than the amounts used in the prior art. On the other hand, when the polymeric additives are present in a fairly high percentage, problems arise with the structure in the form of possible delamination due to incompatibility between the components of the mixture, so that it is preferable to use percentages that do not exceed the critical limit of 10% or even 8%, whereby satisfactory mechanical properties of the mixture are maintained, and a satisfactory barrier effect is ensured at the same time. In a special embodiment of the invention, these additives are introduced into polyethylene terephthalate in an amount of 3-9%, and especially 5-8 wt-percent, which further reinforces the effect mentioned above. A particularly notable advantage here is that it is possible to achieve opaque PET containers whose walls are white and opaque, i.e. have a high colour density without the addition of a white pigment, the colour density being a measure of opacity. [0022] Another notable special advantage obtained according to the invention by adding polypropylene is that it considerably improves the intrinsic viscosity (IV) of the processed preform material in comparison with that of conventional, mineral-filled PET. The intrinsic viscosity is a measure of the ease with which the preform can be processed in a stretching and blowing device that converts it into the final container. Opaque preforms with quite a large amount of pigment have significantly lower intrinsic viscosity than ordinary preforms, so they lack the required strength in the melt form during the blowing process. This makes it more difficult to stretch and blow the preform into a bottle with the required properties, especially the required wall thickness distribution. [0023] By contrast, the preforms with added polypropylene instead of added pigments have a high intrinsic viscosity and a high strength in the molten state, so they are much easier to process in conventional stretching and blow-moulding machines. The direct result of this is that containers with a much lower weight can be manufactured with polymeric additives than with large amounts of pigments according to the standard prior art. Since the density of polypropylene is 30% lower than that of PET, the PET-PP mixture is lighter, and the weight of the container is less as well. So both the preforms and the containers obtained in this way are much lighter than the conventional ones. [0024] A PET structure has recently been introduced that consists of a single layer of an opaque white PET layer but with a fairly large amount of pigment, namely titanium dioxide or zinc sulphate. The disadvantage of this structure is that a relatively large pigment charge of up to 8% is necessary, which is a drawback in Injection moulding. Another undesirable effect occurs in the heating of preforms and their blowing into containers. Furthermore, the protection from light achieved here is unsatisfactory. Finally there is an adverse effect on the cost. [0025] Some other known polyethylene packaging units have a three-layer structure with a light-barrier insert provided by a black polyethylene layer in between two white polyethylene layers, one on either side of it. A six-layer structure is also known, which is formed by placing the following layers one over the other: a white polyethylene layer, a black polyethylene layer, an adhesive, an ethylene—vinyl alcohol (EVOH) copolymer layer, another adhesive layer, and finally again a black polyethylene layer, the aim being to provide a barrier to both light and oxygen. A three-layer PET structure consisting of a black PET layer between two white PET layers is also known. In an interesting embodiment of the invention, the polymeric additive is incorporated in such a multi-layer structure having a black PET middle layer. Thanks to this measure, virtually all transmitted light can be excluded. So the combination of this polymer addition technique with a central black PET layer in a multi-layer structure has a certain effectiveness. [0026] However, the disadvantage of especially the first two structures and to some extent of the last of the above structures is that the amount of white pigment incorporated in the outside layer must be quite large in order to prevent the black colour of the middle layer shining through. The fact is that this would cause a colour shift of the bottle surface to grey, which would leave a visible trace at the outer wall which is visible to the consumer. This smudging is most undesirable. To avoid this, the containers must be made with a white outside wall that is thick enough to screen the inner black layer completely in order to make it virtually invisible. However, this makes the bottles relatively heavy and expensive, as well as difficult to blow, since the white pigment must be used in quite a large amount. [0027] According to an advantageous embodiment of the present invention, a preform with a multi-layer structure is thus proposed with a white PET intermediate layer. [0028] In another embodiment of the invention the preform contains a certain amount of fragmented metal in the above mixture, especially in powder form and preferably in the form of very small particles having a high dispersibility, so that the metal powder can be homogeneously distributed, the quantity used being especially about 2% and preferably not exceeding 1%. A useful advantage of this is that the resulting containers are considerably more recognizable, due to the presence of metal in them. This makes it easier to sort the containers when they are being recycled. In addition, the containers can also be coded in this way. [0029] It is also possible here to achieve a particularly remarkable mirror effect on the inside of the wall of the container. This increases the number of possible applications of the containers with a light-barrier effect to include tubes for toothpaste and other cosmetics and for flowing foods such as mayonnaise and ketchup, the containers then having a semi-rigid wall, in addition to the containers with a rigid wall mentioned above. [0030] According to a further preferred embodiment of the invention, the preform comprises a certain amount of iron-containing metals, especially stainless steel, the magnetism of which is useful when it comes to recycling. [0031] Alternatively, the preform contains a certain amount of non-ferrous metals in the mixture mentioned above. [0032] According to a further remarkable embodiment of the invention, the surface of the PET containers can be transformed by changing the nacreous appearance to a metallized one, especially a silvery metallic appearance, by suitably incorporating additives during the blowing of the preforms into containers. The metallized appearance of the surface can be attributed to additional incompatibility between the two polymers, which in turn is due to the stretching of the material in the cold, which makes the nacreous surface additionally turn white, which nacreous effect then makes disappear it or reduces it, creating a mirror-like metallic appearance on the processed product. [0033] The present invention is also related to a process for making opaque containers, including multi-layer polyester containers, by injection-moulding opaque preforms and by co-injection, followed by blowing the preforms to containers. [0034] This involves the preparation of an immiscible composition that is naturally white, i.e. white without any pigments. The immiscibility is manifested in the orientation of the preform when it is being blown into a container, since the surface of the material is changed from having a white appearance to having a nacreous one, at least in the regions where the preform is stretched. [0035] The light transmittance data can be further improved by adding a small amount of colourants to the PET/PP mixture, typically about 2-4 wt-% or about 5-8 wt-%, according to whether the container has a multi-layer or a single-layer structure, respectively. This yields results which are directly visible to the naked eye. [0036] According to an additional remarkable embodiment of the invention, both the nacreous and the metallized finishes can be coloured by changing the white base either by adding coloured PP pigments to it, or by using a coloured intermediate layer in the case of a multi-layer structure. [0037] Further features and properties of the preform, the container and the process will emerge from the following description of some embodiments of the invention, which are illustrated with the aid of the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0038] FIG. 1 shows a diagrammatic cross-section of a preform, taken along its longitudinal axis according to a first embodiment of the invention. [0039] FIG. 2 shows a diagrammatic cross-section of a preform, also taken along its longitudinal axis according to a second embodiment of the invention. [0040] FIG. 3 represents a front elevation of a first embodiment of a container according to the invention. [0041] FIG. 4 is a front elevation of a further embodiment of a container according to the invention. [0042] FIG. 5 to 9 show a first set of graphs based on measurements of the light-barrier properties and some related parameters. [0043] FIGS. 10 to 21 show a second set of graphs based on measurements of the light barrier properties and some related parameters in the case of single layer preforms represented in FIG. 2 . [0044] FIGS. 22 to 24 show a third set of graphs based on measurements of the light barrier properties and some related parameters in the case of multilayer preforms represented in FIG. 1 . DESCRIPTION [0045] This invention here is generally involved with preforms and containers which are opaque and intended for containing products that are sensitive to radiation and especially light, such as milk, dairy products, fruit juices and so-called functional drinks with nutrients, which can thus be effectively protected from photo-oxidation and from the degradation of the contents based on photo-oxidation. [0046] FIG. 1 shows a preform 10 with a wall 7 and a neck 8 in cross-section taken along the longitudinal axis l. This is a three-layer structure consisting of a base material which is composed of a primary plastic, which forms an outer layer 1 and an inner layer 3 , with an intermediate layer 2 between them, consisting of a secondary plastic. The primary plastic is advantageously polyethylene terephthalate, and the secondary plastic may also be polyethylene terephthalate. The primary base layer has a whitish and opaque appearance, so it reflects a large part of the incident radiation, especially light when it impinges on the wall as shown by the arrow y 1 . The outer layer 1 is made opaque by adding a thermoplastic polymeric additive 5 to PET in an amount of even only from 1 wt-% upward, shown here by cross-hatching. The outer layer 1 therefore forms an effective light barrier, the light-blocking effect whereof can be further increased if need be by the intermediate layer 2 which is downstream. [0047] Said thermoplastic polymeric additive 5 is preferably polypropylene. It can be mixed with PET in an amount of 1-10 wt-%, if required 5-8 wt-%. [0048] In one of the examples, the intermediate layer 2 containing polypropylene can be completely black, so that any rays that may have traversed the outer layer 1 of the preform are absorbed by the intermediate layer 2 , which has a high radiation-absorbing capacity and acts as a downstream radiation filter having a virtually total radiation blocking function, so that virtually no rays can penetrate past the intermediate layer 2 , as a result of which the content of the container is no longer attacked by external radiation. This is indicated schematically in FIG. 1 by the arrows y 1 and y 2 , respectively. [0049] This embodiment is particularly useful when the preform is to be blown into a container and especially into a bottle for UHT milk. In this case, the intermediate layer 2 also acts as a gas barrier, in addition to excluding the light by absorbing it, whereby the oxygen penetrating from the outside is therefore also absorbed by it, in such a way that the milk is not attacked by said outer oxygen particles. This gas barrier effect is therefore combined here with the light barrier action of the outside and inside layers 1 and 3 . [0050] The general advantage of a multi-layer structure is that undesirable external substances that may penetrate through the outside layer 1 are finally fully blocked by the intermediate layer 2 , acting as an exclusion barrier, which provides extra safety. [0051] To optimize the structure, the intermediate layer 2 can be changed from black to grey with the aid of polypropylene or to other colours that are supported on grey with the aid of polypropylene, in order to ensure the same maximum light exclusion. [0052] The amount of additives 5 in the intermediate layer 2 can be increased to very high levels compared with the usual situation, because the intermediate layer, with e.g. only about 10% of the total thickness, does not affect the mechanical characteristics of the container and so it does not influence either the blow moulds used for the preforms or the co-injection thereof. These characteristics mainly come from the inside layer 3 and the outside layer 1 , which jointly make up about 90% of the three-layer structure 10 . [0053] Furthermore, a plurality of other colouring additives and colourants can be incorporated in the intermediate layer 2 more easily than in the customary situations with PET, because one can use lower injection temperatures for the intermediate layer than for the outside layer 1 and the inside layer 3 . This opens up a very wide range of possibilities for the incorporation of other and/or more additives, particularly in the intermediate layer, which would not be possible with preforms having a single-layer structure. [0054] With a paler colour for the intermediate layer, a smaller amount of colouring additives is needed in the outside layer, which has a covering function, because a paler colour is easier to hide by a white outside layer. This has a quite favourable effect by reducing the cost and improving the ease of blowing the preform 10 . It is therefore possible to use opaque preforms with a thick wall, which would not be possible otherwise under normal conditions. [0055] In addition, the colour of the intermediate layer 2 and the colour of the outside layer 1 can be blended and adjusted to each other if the required colour of the outside surface is not white, such as blue, red, gold, yellow or orange, etc. Such situations can mainly arise from the marketing requirements for the recognizability of said containers, in which PET is a good base material because it offers numerous possibilities in this respect, including a great variety of designs and shapes for the containers. The colour combination mentioned above can be utilized to the utmost by making the outside layer 1 transparent but coloured, thereby providing further options by using any possible colour combination required. This also improves the light barrier properties. [0056] The following examples illustrate the further improvements in the barrier properties of the container wall, not only for light but also for oxygen. An additionally improved oxygen barrier that goes beyond the ordinary PET can be incorporated for the packaging of oxygen-sensitive dairy products that contain basic nutrients such as vitamins, proteins, carbohydrates, starches, essential fatty acids, etc. This can be achieved by incorporating in the intermediate layer 2 materials with improved barrier properties, such as aromatic or aliphatic barrier plastics, nylon and aromatic polyesters such as for example: [0057] polyethylene 2,6-naphthalate (PEN) [0058] polyethylene terephthalate ionomer (PETI) [0059] polyethyleneimine (PEI) [0060] polytrimethylene naphthalene 2,6-dicarboxylate (PTN) and [0061] polyethylene terephthalate—polyethylene naphthalate copolymer (PETN). [0062] Alternatively, the same aim can also be achieved by adding an oxygen scavenger, such as an oxidizable polyester or an oxidizable nylon. [0063] This may further best be achieved by incorporating both a material with improved barrier properties and an oxygen scavenger, so that the inside of the container is protected not only from light but also from oxygen. [0064] In this way, the incorporation of polymeric additives in the PET base material in combination with the additional use of colour additives in both multi-layer and single-layer structures can give rise to a great variety of combined colour effects that not only ensure the technically desirable light barrier properties but also offer visual advantages facilitating the identification of the product. [0065] On the other hand, a single-layer structure 40 is satisfactory for some applications in the dairy sector, especially for products derived from milk, where the degrading action of oxygen is less critical. Said single-layer structure is shown in FIG. 2 . Any colour can be used in these applications, and a single-layer milk bottle can be made by the addition of the required coloured pigments and colouring materials. [0066] FIG. 3 shows the front view of a container of the bottle type 20 obtained by stretching and blowing a preform 10 or 40 of the type shown in FIGS. 1 and 2 . The outer wall 21 is visible and has a special appearance 22 indicated here by light stippling. This remarkable effect is caused by a nacreous appearance 22 that the bottle 20 presents to the consumer, making it not only particularly attractive but also easier to recognize. The nacreous effect is promoted by the biaxial stretching of the preform, i.e. its stretching both in the radial and in the longitudinal direction, and by the blowing of the preform to form the container. This nacreous effect is is achieved from the delamination occurring in the mutually joined but immiscible primary base materials and polymeric additives, wherein their immiscibility is in turn due to their mutual incompatibility. It is therefore the choice in full awareness of incompatible materials as constituents of the plastic mixture which creates surprising nacreous effects. [0067] This nacreous effect 22 is not only an advantage in the presentation of the product but also serves a technical purpose by making the resulting outer surface 21 quite reflective. The resulting surface therefore already has one of the three fundamental properties characterising a light barrier, which are low transmittivity, high absorptivity and high reflectivity. [0068] What is ingenious here is that this nacreous effect 22 produces a white gloss if a special polymer is chosen and mixed with PET. Satisfactory barrier properties may be obtained even without the addition of any colouring matter, notably a white one. The whitish pale nacreous appearance 22 can therefore be obtained by stretching the plastic without the use of any colouring matter though. [0069] The barrier properties can yet be further promoted by the addition of a small amount of colourants, typically about merely 24 wt-%, or about 5-8 wt-%, according to whether the container has a multi-layer structure or a single-layer one. This is a considerable advantage from the technical point of view, since the addition of colourants causes problems when a preform is being blown into a bottle. The more pigment it contains the more difficult is the blowing process. The critical value set above at 8% for coloured pigments is a threshold value beyond which the blowing of preforms into bottles becomes considerably difficult. [0070] It has been shown experimentally that the wall 21 can reflect up to 92% of incident light even without the use of colourants, but by incorporating polymeric additives alone, which is more than sufficient for a wide range of applications, such as sleeve bottles, where the printed sleeve can be drawn with virtually any pattern on such a container. This is therefore a fundamental characteristic which is proper to the present container. [0071] An additional advantage lies in the easier blowing of the preform to a container, owing to the possible absence of coloured pigments, which make blowing only difficult. Furthermore, the mechanical properties of the material are not diminished here as they inevitably are when colourants are added. In addition, the thermal stability of the preform is better, so the latter remains stable at considerably higher temperatures. [0072] In addition, the absence or at least greatly reduced presence of pigments, which are relatively heavier than polymeric additives, means that the container formed is very light, being a reduction up to 20 wt-% lighter, while retaining a reflective index of more than 92, together with the possibility of using the customary blowing equipments. [0073] However, an improvement in the light barrier properties for a multi-layer structure in comparison with a single-layer one cannot be expected if no colourants are incorporated in it. So the use of a multi-layer structure is only sensible if colourants are present. In the absence of colourants, the cheaper single-layer structure will suffice. For structures of this type, such as that shown in FIG. 2 , pigments are therefore used in relatively small amounts, yet without exceeding the critical threshold value for blowing. [0074] Further thermoplastic polymeric additives are formed by polyethylene additives, in particular so-called high-density polyethylene known as HDPE, low-density polyethylene (LDPE), medium density polyethylene (MDPE) and linear low density polyethylenes (LLDPE). Further to be considered are polyolefine acetate co-polymers, such as methyl (EMA), ethyl (EEA), vinyl (EVA) acetate, polyethylene co-polymers of vinyl alcohol (EVOH). [0075] Polystyrene (PS), polyvinylchloride (PVC), polyethylene-terephthalate (PET), polyethylene-isophthalate (PEI), polybutylene-terephthalate (PBT), polyethylene-naphthalate (PEN), polytrimethylene-naphthalate (PTN), polytrimethylene-isophthalate (PTI), polytrimethylene-terephthalate (PTT), phthalic acid copolymers, polycarbonate (PC), acrylonitrile butadiene styrene (ABS), polyamide 6 (PA6), polyamide 66 (PA 6,6). [0076] FIG. 4 shows a variant of the bottle 30 , where the darker shaded zones 31 indicate a metallized appearance 32 of the container. [0077] Said nacreous effect 22 , resp. metallized effect 32 , which are due to the addition of a polymeric additive to the primary base plastic, have the intrinsic advantage for light-sensitive products, such as UHT milk, that the surface 21 or 31 of the container 20 and 30 containing the milk reflects a substantial proportion of the incident light in a natural way. In addition, the wall of the container has a great deal of internal refraction. These two phenomena mutually combine to reduce or even prevent the penetration of light. EXAMPLES [0078] In a typical comparison, a one-litre multi-layer bottle with the structure white PET -black PET—white PET weighs 26 grams when made with polymeric additives according to the invention and 32 grams when made by the traditional technique using a large amount of pigment, which means an approximately 25% saving of material, i.e. a considerable amount. Experiments [0079] Said light barrier properties and said associated three parameters—transmission, absorption and reflection—were determined experimentally by means of a spectrophotometer of the “datacolour” type 650™ customarily used for this purpose, and the data obtained were used to construct the graphs shown in FIGS. 5-9 . [0080] The graphs in FIGS. 5 and 6 show the transmission of radiation that is incident on the container as a function of its wavelength λ in the case of a single-layer structure containing 5% of polypropylene in the first case (see FIG. 5 ) and a structure containing 10% of polypropylene in the second case (see FIG. 6 ). In the case of light transmission, FIG. 5 shows that an extremely strong light-blocking effect is observed when polypropylene additives are added to PET as the primary plastic without any colour additives or colourants. In FIG. 6 , which shows the reflection, the high reflectivity can be observed, which is caused by the nacreous appearance of the wall surface of the container after stretching the original PET/PP preform thereto. [0081] FIGS. 7 and 8 similarly show the transmission and reflection of multi-layer structures made with the addition of 10% propylene additives and further with the addition in the amount of 2% of a white colourant in the outside layer 1 and with 2% of a black colourant in the intermediate layer 2 . Both FIGS. 7 and 8 indicate the great effect on the transmission which is generated by the incorporation of a black layer as intermediate layer, ensuring the total exclusion of light. As to the reflectance shown in FIG. 8 , the reflecting effect of the nacreous outer surface of the wall can be observed, just as indicated in the case of the one-layer structure represented in FIGS. 5 and 6 , and partly by the internal refraction of light. [0082] Measurements carried out on single-layer bottles indicated that the transmitted light is reduced to only 5%, which is an excellent result compared with PET, which is not completed with polypropylene additive and without white colourants, as set out hereafter, especially in connection with FIGS. 10-11 . [0083] If the container is only made of the primary plastic PET, one could observe that up to about 90% of the light is transmitted. [0084] FIG. 11 refers to the case when 2% of additives in the form of polypropylene is added to the primary base material. It can be concluded from this graph that even such a modest amount of polypropylene additives causes a significant reduction in the amount of light allowed through. [0085] It can be observed on FIG. 12 showing the addition of polypropylene up to 5% that the light rays transmitted through the container wall are further limited to 15%. [0086] It can be deduced from FIG. 13 that a light transmission is limited to merely 5% when adding the same additional amount of polypropylene additives of 5% yielding a total amount of 10% PP. It is thus striking that the light exclusion is not linear with the addition of polypropylene additives, but instead decreases relatively faster. For example, one may state when comparing FIGS. 11 and 13 that five times more additives correspond to ten times less light transmission. A conclusion here is then that the adding of polypropylene additives up to 10% makes the light transmission decrease by 95%, which is thus a quite remarkable result. [0087] A further group tests shown in FIG. 14 to 17 is set out hereafter. In this group 5% polypropylene additives are respectively added to the primary base material PET, with a further addition of white colourants in an amount comprised between 2% and 8% respectively, with each time an increase of 2%, i.e. 4 and resp. 6% white. The graphs in FIG. 14 show that the addition of 2% colourants reduces the transmission of light rays to approximately 2%, while in the addition of colourants is doubled to 4%, the transmission of light is reduced by half to approximately 1% as appears from FIG. 15 . [0088] Multiplying colourants by three times up to 6% causes a further reduction of light to merely approximately 0.3% as shown in FIG. 16 . [0089] FIG. 17 shows the maximum addition of white according to the present tests in the amount of 8% with a light transmission reduced to approximately merely 0.15% of the incident light. [0090] It can therefore be deduced from the four preceding test series that the further addition of white colourants by 2% reduces the light transmission from 15% as shown in FIG. 12 to merely 2% as shown in FIG. 14 . With regard to this, a moderate addition of white colourants is able to reduce the light transmission to a very low level of only 0.15% light transmission. [0091] Similarly as in the preceding tests series which are represented In FIG. 10 to 13 , it can be stated again that the reduction of light transmission is not linear in function of the addition of colourants since multiplying the colourants by four from 2 to 8% generates up to approximately 13 times more light transmission, which can be considered as a remarkable result as well. [0092] A still further series of four tests represented in FIG. 18 to 21 is set out hereafter. These tests take place in quite similar conditions, under doubling however of the added percentage of polypropylene additives from 5 to 10%. [0093] FIG. 18 shows a graph of transmittance in % in function of the wavelength of the incident radiation, wherein it may be observed that adding 2% of colourants with a doubled addition of polypropylene additives to 10%, transmits only approximately 1% of the incident light radiation, i.e. the half of the transmittance under similar conditions, with the addition of the half of polypropylene additives to 5% however, as shown in FIG. 14 . [0094] The subsequent FIG. 19 to 21 are similar representations with each time 2 additional percents of colourants addition. With the first doubling of the colourants to 4% represented in FIG. 19 , there is still only 0.4% light transmission. When tripling the colourant addition white to 6%, the graph represented in FIG. 20 shows that the light transmission is still further reduced by half to 0.2% of the incident light radiation. [0095] Finally when multiplying by four the white colourant addition to 8%, the light transmission is reduced to only 0.1% of the incident radiation as shown in FIG. 21 . [0096] A comparison of the test results within this additional group of measures represented by FIG. 18 to 21 teaches again that the reduction of light transmission is not linear with the increase of colourants, but with a certain acceleration effect with amplifying reduction of the light transmission with respect to the addition of colourant additives. [0097] Consequently, it can be deduced from the latter series of measurements that the graphs appear two times lower compared to the previous series measurements with the half of polymer additives, i.e. 5% PP, including in the presence of white colourant, when further adding polypropylene as polymer additive up to 10%. [0098] At last, a last series of measurements is represented in FIG. 22 to 24 showing analogue graphs, each time with colourant additives in the amount of 8%, the first one whereof in FIG. 22 in the absence of polymer additives, which means only with colourant additives, whereas the two subsequent figures represent graphs each time with the addition of 5% polymer additives, i.e. 5% polypropylene in FIG. 23 , resp. 10% polypropylene in FIG. 24 . [0099] FIG. 22 lets light radiation through up to approximately 1%, whereas the addition of merely 5% polypropylene transmits light radiation up to merely 0.15% of the incident light radiation. When doubling polypropylene to 10%, the light transmission is limited to approximately 0.1% as shown in FIG. 24 . [0100] Both latter FIGS. 23 and 24 correspond logically with FIG. 17 and respectively 21 above. It can be deduced from these figures that the addition of white colourants without polymer additives may cause up to 1% light transmission at a wave length of 550 nm, but not less. Only the addition of polymer additive polypropylene may bring back the graphs to a level up to 0.1%, which is extremely low. Lower levels of colourant additions white with polymer additives reproduce the same performances as observed in FIG. 10 to 21 . [0101] It is to be noted here that these measurements were carried out by means of a spectrophotometer which is a worldwide recognised device which provides extremely reliable measurement results, so that the tests set out above should be considered as particularly relevant. All abovementioned tests were carried out with each time the same bottle. [0102] Besides, only the transmitted light radiation getting through the container wall was measured, since only this amount of radiation is detrimental for the product which is to be contained in the container. The results set out above should further be related with respect to admissible radiation transmission values in the intended field. In view thereof, it should be considered that when the product to be contained is milk, the maximum admissible transmission value amounts to 0.3%. In other words, this means that for milk preforms the addition of colourants is suitable in the amount of 6% in case 5% polymer additives are added as represented in FIG. 13 . In case for instance 10% polymer additives are added, the amount of white colourants may be reduced to a percentage which is comprised between 4 and 6, e.g. approximately 5% of white colourants, as may be assumed by extrapolating the measurement results of FIG. 19 , resp. 20. This is a remarkable result in the meaning that blowing a preform becomes more difficult as more colourant additives are added. The difficulty of blowing becomes critical, especially as from 4% addition of white colourants and more. It is to be noted here that the performance of the blowing machine may decrease up to 20% and more. In addition, one is also limited in the geometry of the preform because the wall thickness thereof will be smaller than 4 mm, and even up to 3.5 mm. [0103] When further also considering the costs of white colourants such as titanium dioxide or zinc oxide, the usefulness of a minimum addition of white colourants will be appreciated directly. In this respect, it may be stated that very favourable transmission results may be achieved without the addition of colourants. Example of applications in this respect are a maximum value of 0.7% transmission, which is not enough for the filtering of light for some kinds, in particular UHT milk where 0.3 is the maximum transmission. [0104] When adding an amount reduced by half of white colourant additives of the UHT type for the same amount of added polymer additives of polypropylene, i.e. 5%, a light transmission of 2% is achieved. [0105] It can further be observed that the colourants will have a more efficient behaviour regarding light exclusion in the presence of polymer additives of polypropylene. It can therefore be stated that the polymer additives have a synergetic effect on colourant additives. [0106] It can further be observed on most of the graphs that they present an increasing profile in function of the wavelength, whereby it may be stated that the smaller the wavelength of the incident radiation, the easier the incident radiation may be blocked by the container wall. [0107] It is particularly worth noting that the multi-layer structure of the container according to the invention can also be used with an intermediate layer 2 that is similarly white instead of being black. The replacement of the latter by the former according to the invention is possible here thanks to said synergistic effect of the polypropylene-type polymeric additives and colouring additives, ensuring an additional intrinsic light-blocking effect for enabling the achievement of this blocking mode of the intermediate layer 2 without the need of a black intermediate layer with its characteristic light-absorbing function. This also has the outstanding advantage that owing to the invention, the black intermediate layer no longer needs to be covered by a white outer layer as in the conventional types of preform. Achieving this quite remarkable effect is only possible by subjecting the initial preform, i.e. the semi-finished product to biaxial stretching in order to obtain the container as the finished product. It is therefore possible to achieve the absorption of the radiation without any pigmentation, i.e. without the addition of colouring additives that are needed for obtaining an absorbing black intermediate layer, but not for a white light-blocking intermediate layer. A similar effect may be obtained without adding colouring additives or pigments, yet by subjecting the initial preform to biaxial stretching in order to form the container. Owing to this method of biaxial stretching, a crystalline structure is achieved in the polyethylene terephthalate, as a result of which the biaxially stretched container becomes white. [0108] It is therefore possible now to produce a coloured container like a bottle with three layers or more generally a multi-layer structure, by adding a relatively small percentage of colourants or pigments with a suitable incorporation of polymeric additives according to the invention. [0109] It should further be mentioned that it is rather difficult to load PET. Indeed, incorporating additives like pigments and colourants in PET is relatively difficult because the processing temperature used here is high, i.e. from 250 to 300° C., which is undesirable for pigments and colourants. In addition, the pigmentation of PET is much more expensive than that of other plastics. In this respect, there are pigments allowing higher levels of charges, such as e.g. HCAe used in the tests mentioned above. The same light exclusion effect can therefore be obtained here but at a lower cost. However, a multi-layer structure must be used to reduce the transmission to an absolute minimum, i.e. practically to zero. [0110] Owing to the invention, light radiation is absorbed instead of being refracted, and this is achieved merely by using polymeric additives, i.e. with very small pigment or colourant charges or even none at all. [0111] To summarise, multi-layer bottles can be advantageously made with a lower weight and so a lower cost. Another advantage is that the injection moulding and blowing process used here is equivalent as with customary single-layer PET structures, which is not possible with conventional systems. Yet another advantage of the present invention is that the surface of the containers has a nacreous appearance. This is a particularly remarkable effect, which consumers find very attractive. [0112] Furthermore, none of the existing structures mentioned above can ensure an additional oxygen barrier effect over and above that obtained with conventional PET containers, at least for the packing of products that are sensitive to both light and oxygen. In regard thereof, a still further advantage of the invention is that an oxygen barrier can be incorporated in the walls of the container or preform by replacing polyethylene terephthalate in one or more of the layers by a polyester barrier that absorbs oxygen.

Preform, serving as a semi-finished product, for a container intended for containing products therein that are sensitive to radiation in particular light sensitive and food and dairy products, consisting of at least one base layer ( 1 ) made of a primary plastic base material, with a certain amount of additives ( 5 ) incorporated in it ( 1 ), characterised in that said preform ( 10, 20 ) is opaque over virtually the whole extent thereof, wherein a relatively low percentage of plastic additives ( 5 ) is incorporated to generate sard opaque appearance ( 22 ), so as to protect the inner space ( 9 ) thereof which is delimitated by it against external radiation (V 1 , V 2 ) particularly electromagnetic radiation, more particularly light, under normal pressure condition.

FIELD OF THE INVENTION The present invention is directed to a suspension system for a pipe lining machine and more particularly, to a damping assembly for damping vibrations in the belts used to support and rotate pipes during the lining operation. BACKGROUND OF THE INVENTION Concrete-lined pipes of exceptionally large diameter are generally used as buried conduits for conducting drinking water, irrigation water, and other fluids. To construct such a pipe, concrete mortar is placed inside a steel pipe which is then spun to centrifugally distribute the concrete mortar in an even thin layer on the inside wall of the pipe. A machine, generally known as lining machine, is used to perform the operation and basically consists of multiple belt assemblies, usually three to five, which are spaced apart for supporting the pipe along its length. A side view of a pre-existing lining machine 10 is illustrated in FIG. 1 . The side view shows the typical belt arrangement for each belt assembly of the lining machine. Each belt 12 is formed into a loop which wraps around a set of four pulleys, as depicted in FIG. 1 . The pipe is supported by the belts at the portion between the two upper pulleys 14 , 16 . The left upper pulley 14 is generally fixed in position and powered by a drive motor to provide the necessary drive force to spin the pipe at sufficient rotational speeds to adequately pack the mortar on the inside wall of the pipe. The right upper pulley 16 can be adjusted toward or away from the left pulley before the spinning operation to adapt the machine to a range of pipe sizes. The right lower pulley 20 may also be adjusted. The left lower pulley 18 is fixed in position. All pulleys are fixed in position during operation. To mortar line a pipe, the pipe is initially rotated at a steady but relatively low speed and a mortar feeding lance is moved inside the pipe to pour the mortar material along the length of the pipe. The pipe is then accelerated to a desired rotational speed to pack the mortar against the internal pipe wall for a sufficient period of time to allow the mortar to dewater. Due to the elastic property of the belts, the generally uneven roundness of the pipe, and the imbalance in the pipe caused by an uneven mortar thickness caused by the rotation of the pipe around its mass (i.e., gravity) center, the pipe vibrates on the belts while it is rotating. The pipe and the belts together constitute an oscillating system with a particular frequency of its own, its so-called “natural frequency.” When the pipe is rotated at high speeds, the reciprocating movements of the belts come into the natural frequency range of this system. When this happens, the pipe and belts tend to move independently of the motion imparted to them by the drive motor. The vibration of the system is especially large when in the natural frequency of the system before reaching the packing speed. If the pipe is excessively out of balance, the vibration can be very severe and the pipe can bounce off of the belts, causing the belts to slack and sometimes slip away from the pulleys. This damages the belts and may also cause the pipe to fall off of the machine, thereby creating a dangerous situation for both the equipment and human operators of the lining machine. Accordingly, it would be desirable to provide means for dampening the vibration of the system during the spinning operation for the safety of the machine and its operators. SUMMARY OF THE INVENTION According to one embodiment of the invention, a pipe lining machine including several belt assemblies for supporting a pipe to be rotated is provided. The pipe lining machine also includes a base, a drive motor, and several connecting arms for each belt assembly. The connecting arms are connected at a bottom end to the base. At least one of the connecting arms per belt assembly is hingeably connected to the base. Each belt assembly includes several pulleys, each connected to the top end of each of the connecting arms. The pulleys include a drive pulley operatively connected to the drive motor and a movable pulley connected to the connecting arm hingeably connected to the base. A belt formed into a belt loop is wound around the pulleys. An interior surface of the belt loop contacts the pulleys and an exterior surface of the belt loop supports a pipe to be rotated. Means are provided for damping movement of the movable pulley. According to another embodiment, the means for damping movement of the moveable pulley is a damping assembly operatively coupled to the moveable pulley. Preferably, the damping assembly includes a pneumatic suspension member, e.g., an air bellows, coupled to the moveable pulley, and a hydraulic damping member, e.g., a hydraulic cylinder, coupled to the moveable pulley and to the pneumatic suspension member. DESCRIPTION OF THE DRAWINGS This invention may be better understood and its numerous objectives and advantages will become apparent to those skilled in the art by reference to the following drawings: FIG. 1 is a side view of a pre-existing pipe lining machine; FIG. 2 is a plan view of a pipe lining machine according to one embodiment of the invention; and FIG. 3 is a side view of the pipe lining machine shown in FIG. 2 . DETAILED DESCRIPTION OF THE INVENTION FIG. 2 illustrates one embodiment of the invention, which includes two pairs of belt assemblies adapted to support a pipe such that it is free to rotate. A pair of the belt assemblies is typically positioned on either end of the pipe. Only one pair of the belt assemblies is illustrated in FIG. 2 . The other belt assemblies are substantially the same in their construction, mounting, and operation. Hence, the separate parts herein indicated by reference as applied to the pair of belt assemblies 30 , 32 are equally applicable to the other pair of belt assemblies (not shown). Each pair of belt assemblies share a common base 34 (FIG. 3 ). Each belt assembly includes a belt loop 36 wound around four pulley pairs: left upper 38 ; right upper 40 ; left lower 42 ; and right lower 44 . Power is applied to rotate a power pulley, in this embodiment the left upper pulley 38 , to thereby rotate the belt and thus the pipe. Each of the belt assemblies will have the same corresponding power pulley. The locations of the axles of the power pulleys are fixed relative to the base. Preferably a 150 hp drive motor (not shown) is used to drive the power pulley in each of the belt assemblies. A preferable drive motor is capable of rotating pipes weighing up to 20 tons, which may rotate at speeds up to 100 mph at the pipe edge when at the packing speed. The pair of right upper pulleys 40 are rotated on a common axle 45 which is mounted in an adjustable pulley supporting arm 46 . The adjustable pulley supporting arm 46 is adjustable at its upper and lower ends to accommodate pipes of different size on the belt loop 36 . The upper end of the adjustable pulley supporting arm 46 is attached with pins to one end of a connecting bar 47 . At a point spaced from that one end, the bar is also connected to the upper end of a pedestal 48 built on the base 34 . The connecting bar 47 can be connected to the upper end of pedestal 48 with a pin through one of a series of holes along its length to adjust the position of the right upper pulleys 40 for relatively minor changes in pipe size. The lower end of the adjustable pulley supporting arm 46 is hingeably connected to the base. It can be connected to one of the two or more holes 49 provided in the base to adjust for a major change in pipe size. Holes 49 are located laterally along the base at positions that are spaced various distances from the left pulleys. The left lower power pulley 42 is fixed in position. Each pulley forming the right lower pulley pair 44 is supported by a hinged pulley supporting arm 50 which is hingeably connected at its lower end to the base 34 . The upper end of each hinged pulley supporting arm 50 , which extends above the pulley, is connected to a damping assembly 52 by a fork-shaped link (or a yoke) 54 . Preferably, each hinged pulley supporting arm is pivotally connected using a pin 59 to a hole 61 in tongue 55 connected to the base 57 of the fork-shaped link. Preferably, the tongue has a series of holes 61 along its length. The pulley supporting arm 50 can be connected to any such hole 61 using a pin. As such, the position of the hinged pulley arm can be adjusted. Each damping assembly includes air bellows 56 positioned inside a housing 58 . A front end 80 of the air bellows is secured to the housing structure. The housing 58 has a supporting leg 60 extending downward and connected with a pin 51 to an arm 63 extending from the base 34 . Near its upper end, the housing is secured by an eye bolt 53 to another pedestal 62 which is preferably built on the base. The forked double arms of the link 54 extend around the bellow housing and connect with each end 65 of a shaft 64 transversely secured to the rear end of the air bellows. The shaft ends 65 extend through a slot opening 66 on each of the side walls of the housing. A wheel 68 is mounted at each end of the shaft inside the link and rides in a corresponding one of these slot openings inside the link. When each bellows is inflated with air pressure, it pulls its corresponding lower pulley 44 via the fork-shaped link and stretches (i.e., tensions) the belt to lift and support the pipe. Before the belt is driven with a pipe in place, the bellows should be inflated with air pressure to a level positioning the shaft wheels 68 midway along the slots 66 . In this regard, the bellows will be able to oscillate as necessary in either direction along the slot 66 . The bellows work as a suspension and tensioning device to take up the belt slack when the pipe vibrates. A hydraulic cylinder 70 is mounted in an extended housing 72 secured to the rear side of each of the bellows housing 58 . A cylinder rod 74 extending from the hydraulic cylinder is connected transversely to the shaft 64 . The rod is connected on the side of the shaft opposite the bellows. The hydraulic cylinder provides resistance to the movement of the shaft which, ideally, is proportional to the velocity of the force attempting to move the shaft. The cylinder is filled with hydraulic fluid and its ports are connected to a system of control valves (not shown) for damping down vibration. Such valves and their operation are known in the art. One of the control valves is preferably a throttling valve that is set to relieve fluid pressure generated in the cylinder by the movement of the shaft, and thus, decrease the resistance provided by the cylinder when a force equal to or greater than a preselected magnitude is applied to the shaft. This pressure relief setting is preferably set to correspond to a force less than 25% of the pipe weight. According to a preferred embodiment of the present invention, the hinged lower right pulley 44 moves laterally in response to slack and vibrations in the belt loop 36 caused by the vibrating pipe. As the lower right pulley 44 moves laterally, it moves the fork-shaped link 54 which causes the shaft 64 to move along the slot openings 66 formed on the bellows housing 58 sidewalls. The movement of the shaft and thus, of the lower right pulley, is resisted by the air bellows and the hydraulic cylinder which are coupled on opposite sides of the shaft. The bellows and the hydraulic cylinder resist movement of the shaft and thus, of the lower right pulley, toward the center of the pipe (i.e., the movement compressing the bellows). In other words, the bellows resists the belt detensioning movement of the lower right pulley. Such movement is caused by the weight of the pipe or when the pipe bounces on the belt. When the pipe bounces off the belt, the bellows expands in a direction keeping the tension of the belt on the pipe so as to keep the belt in contact with the pipe. To mortar line a steel pipe, the pipe is rotated at a steady lower speed and a mortar feeding lance is moved along the length of the interior of the pipe to pour the mortar material into the pipe. The pipe is then accelerated to a desired speed for a sufficient period of time to pack the mortar against the pipe wall and to remove the excess water from the mortar. As a rule, the pipe is not perfectly round and hence rotates about its mass center rather than its geometric center which results in an eccentric rotation. During rotation of the pipe, the belt itself acts as a low mass spring and responds to high frequency, low amplitude vibrations caused by the eccentric rotation of the pipe. The pipe and the belt together constitute an oscillating system with a particular natural frequency. When the pipe is rotated at high speeds, the reciprocating movements of the belt come into the natural frequency range of this system. The oscillations associated with the natural frequency are experienced along a range of rotational speeds evenly distributed about the rotational speed at which true natural frequency of the system occurs. For example, if the true natural frequency of the system occurs at 50% of the packing speed, the range at which oscillations associated with the natural frequency will be experienced by the system is in the range of about 40% to 60% of the packing speed. When in operation, the bellows acts as a support for supporting the weight of the pipe. In essence, the belt in combination with the bellows acts as a two spring system with the two springs in series. The bellows can be expanded as necessary by filling with air to support heavier or lighter pipes. As the pipe rotates and jumps on the belt, the minor vibrations are absorbed by the stretching of the belts. Large amplitude vibrations are absorbed by the bellows. As the impact on the belt by the pipe increases, the larger amplitude vibrations are damped by the hydraulic cylinder which acts as a shock absorber. It has been found that the action of the air bellows actually lowers the natural frequency of the system. The hydraulic cylinder which acts as a shock-absorbing device further damps the vibration and reduces oscillation at the natural frequency of the system. This results in a smoother ride for the pipe with better lining quality and a longer belt life. This damping action also makes the machine safer to operate. Moreover, the natural frequency of the system is reached at lower rpms. This is advantageous in that it makes it easier for the motor to drive the spinning pipe through the natural frequency of the system. Furthermore, the packing speeds are isolated further away from the rotational speeds at which the natural frequency occurs and hence the system is less affected by the excess vibrations created in the system when near its natural frequency.

A belt assembly for a pipe lining machine used to make concrete lined pipes. A pipe to be rotated is supported on the exterior surface of a belt loop wound around several pulleys, including a drive pulley and a displaceable pulley which moves laterally in response to slack and tension in the belt loop. A damping assembly is connected to the displaceable pulley to damp vibrations in the displaceable pulley. Preferably, the damping assembly includes a pneumatic suspension member, e.g., air bellows, and a hydraulic damping member, e.g., a hydraulic shock-absorbing cylinder, connected in series to the displaceable pulley.

FIELD OF THE INVENTION The present invention relates to an apparatus and method for producing highly collimated light and, more particularly, to a method for producing highly collimated light for use with a tiled, flat-panel liquid crystal display (LCD). BACKGROUND OF THE INVENTION Conventional flat-panel displays made in accordance with known liquid crystal display technologies have heretofore been both limited in size and expensive to manufacture. A large display device may be constructed at reduced cost by assembling multiple smaller display "tiles". However, it is necessary to make the internal seams visually imperceptible to create a pleasing display. For the seams to be visually imperceptible and for the display image to be sharp, the light used to illuminate the display must be highly collimated. A collimated light source must allow essentially no visible energy to radiate beyond an allowable off-normal angle. The allowable off-normal angle is prescribed by the tile thickness and the cover plate mask and back plate mask dimensions. It is defined as the critical off-normal angle below which light from the illumination source must not enter the tile to tile seam area. This type of tiled display construction is described in U.S. Pat. No. 5,661,531, entitled "Construction and Sealing of Tiled, Flat-Panel Displays"; and co-pending U.S. patent application, Ser. No. 08/593,759, filed on Jan. 29, 1996, entitled "Tiled, Flat-Panel Display Having Invisible Seams". Both U.S. Pat. No. 5,661,531 and co-pending application Ser. No. 08/593,759 are hereby incorporated by reference. Typical practice for LCD illumination uses area light sources such as fluorescent tube arrays. A collimator must focus the light from the light source forward, toward the flat-panel display, forcing essentially all visible light energy to fall within the off-normal angle described hereinabove. Most commonly used collimators do reduce the light intensity at large off-normal angles, but do not perform well enough at small off-normal angles for use with a tiled, flat-panel display having visually imperceptible seams. A seamless appearance in a tiled, flat-panel display requires that unwanted visible light energy outside of the off-normal angle be reduced to less than one percent of the intensity of the light at a normal angle. This percentage is derived in a 1992 reference paper by G. Alphonse and J. Lubin entitled "Psychophysical Requirements for a Tiled Large Screen Display" published in SPIE Journal, Volume 1664, pp. 230-240. In tiled, flat-panel constructions featuring a cover plate with an integral screen, the light must also be collimated to such an extent that essentially no light from one pixel can reach the screen area associated with any other pixel. Adherence to this requirement produces the sharpest possible image on the tiled, flat-panel display. It is therefore an object of the invention to provide an apparatus and method for producing highly collimated light suitable for use with a tiled, flat-panel display having visually imperceptible seams. It is a further object of the invention to provide a means of reducing the intensity of visible light energy, which falls outside of a desired, off-normal angle, to an acceptable level. It is yet another object of this invention to maximize the pixel resolution in tiled, flat-panel displays by providing highly collimated light. It is a further object of this invention to produce a wide area, collimated light source having a small depth to enable building tiled, flat-panel displays having a small overall thickness. The present invention provides an apparatus and method for producing the highly collimated light required for use with a seamless, tiled, flat-panel display. SUMMARY OF THE INVENTION In accordance with the present invention, there is provided an apparatus and method for collimating light for use with a tiled, flat-panel display having a seamless appearance (i.e., having visually imperceptible seams). Both U.S. Pat. No. 5,661,531 and co-pending U.S. patent application Ser. No. 08/593,759 describe methods for producing Active Matrix LCD (AMLCD) displays by using multiple tiles coupled together in large, visually seamless arrays. The light from the illumination source for the display must be collimated to meet stringent optical standards to ensure optimum performance of the total display system. Collimation and distribution of light from the light source is typically accomplished by some or all of the following components: diffusers, brightness enhancing films, optical lenses, light-directing screens, collimating sheets, wave guides and opaque masks. The use of these components adds cost, complexity and thickness to the final display system and, in the end, they do not collimate the light sufficiently to produce a seamless appearance in a tiled, flat-panel display. The present invention provides a novel method for collimation in a tiled, flat-panel display environment. In the inventive method, a lattice of depth, H, having an x,y cell width, W, is placed a distance, D, behind the bottom mask of the tiled, flat-panel display assembly, but in front of the illumination source. The lattice is formed from a thin, non-reflective material so that the acceptable light passing through the lattice is not "blocked" to any significant extent, but the unwanted (off-axis) light impinges upon the lattice cell walls and is absorbed. The lattice is formed from a material with surfaces that have small and uniformly minimal specular and diffuse reflectivity across the visible spectrum of light. The lattice is made with a specific relationship of cell height to cell width, typically between 1:1 and 3:1. Such cell height to cell width ratios generally keep light rays that are beyond acceptable off-normal angles, from entering the display assembly (back plate, tiles, cover plate, etc.). The lattice is placed a distance behind the display, typically between one and three times the lattice thickness, so that the cell walls of the lattice are not "imaged" onto the back of the display assembly. Such a lattice used in this way is a simple, practical way to achieve the highly collimated light required for visually imperceptible seams in a tiled, flat-panel display. BRIEF DESCRIPTION OF THE DRAWINGS A complete understanding of the present invention may be obtained by reference to the accompanying drawings, when considered in conjunction with the subsequent detailed description and in which: FIG. 1 is a sectional, schematic view of a flat-panel display with its associated illumination source; FIG. 2 is a plan view of three embodiments of collimating lattice geometries; FIG. 3 is a graph showing the light-collimating ability of each element depicted in FIG. 1; FIG. 4 is a schematic representation of a pixel and its neighboring pixels in a tiled, flat-panel display; and FIG. 5 is a sectional, schematic view of a flat-panel display, including an optical collimator. DESCRIPTION OF THE PREFERRED EMBODIMENT Generally speaking, the invention features an apparatus and a method for constructing a highly collimated light source for use with a seamless, flat-panel display. The degree of collimation required to achieve a seamless appearing display with a sharp image may be obtained with an open cell lattice having non-reflecting side walls. Both the lattice dimensions and the position of the lattice relative to the display are chosen so as to provide optimum collimation and illumination. Referring now to FIG. 1, a cross-sectional view of a tiled, flat-panel display assembly, using the inventive collimating lattice, is shown generally at reference numeral 10. Display assembly 10 utilizes a conventional light box 12 in conjunction with the collimating lattice 14 and a tiled, flat-panel display 16. A conventional light source for an LCD display would normally consist of three elements: a light box 12 housing one or more fluorescent lamps 18, a diffuser sheet 20, and an optical collimator (brightness enhancing films) 22. This invention adds a fourth element: a collimating lattice 14, having thickness H, and displaced distance D from the LCD display 16. Lattice 14 is used to produce the highly collimated light needed for use with a tiled, flat-panel display having visually imperceptible seams and a sharp image. Dimensions H and D will be discussed in detail hereinbelow. Referring now to FIG. 2, there are shown plan views of three geometric shapes of collimating lattices suitable for use in practicing the method of the present invention. The upper portion of FIG. 2 shows a lattice of square cells 30; the middle portion of FIG. 2 shows a lattice having triangular cells 40; and the lower portion of FIG. 2 shows a lattice formed from hexagonal or honey comb cells 50. The lattice cells 30, 40, 50 can be characterized by a typical cell width dimension W, of 3-5 mm, 32, 42, 52, respectively. The lattice 30, 40, 50 may be constructed from any material that is thin, such as plastic, paper, aluminum, or other metals. The interior surfaces of the cells, not shown, may be plated, dyed, painted, or treated in any other way known to those of skill in the art, to produce a surface with uniformly minimal specular and diffuse reflectivity across the visible spectrum of light. Instead of surface treatment, the material itself can be non-reflective. The wall thickness of the cells, not shown, is minimized to permit as much light as possible to pass through the lattice 30, 40, 50. In the preferred embodiment, a readily available aluminum honey comb lattice is spray- or dip-painted with a matte black paint. Referring now to FIG. 3, there is shown a graph 60 of the relative collimating efficiencies of various collimating elements of the light source shown in FIG. 1: diffuser 20, optical collimator 22 and lattice collimator 14. Referring now again also to FIG. 1, an ideal diffuser 20 should disperse the light from the lamps 18 forward in all directions, at uniform brightness. Light intensity should be constant at all angles measured with respect to a line 24 normal to the front or rear surface planes of the diffuser 20. Light of this nature is referred to as Lambertian. The light from lamps 18 first passes through diffuser 20 and then passes through an optical collimator or brightness enhancing film 22. These readily available devices are usually constructed of micro-geometry prismatic arrays or channels which change the Lambertian-like light distribution from a typical diffuser to a more forward peaked distribution, producing the light intensity versus off-normal angle curves 62 and 64, respectively. The light energy at angles above the desired cut-off angle (i.e., that which remains when only diffuser 20 and optical collimator 22 are used) is too high for use with a tiled, flat-panel display having visually imperceptible seams and a sharp appearance. The addition of collimating lattice 14 in accordance with the invention removes virtually all light beyond the desired cut-off angle as shown in curve 66, thus producing the desired seamless, sharp appearance of the display. Referring now to FIG. 4, there is shown generally at reference number 100, a schematic view of a target display pixel 102 adjacent to a tile edge 104. Neighboring pixels, 106, 108, 108', 110 and 110' are also shown. Light entering the rear of the display (arrow 112) in the target pixel area 102 at off-normal angles beyond the desired cut-off angle exit the display in a neighboring pixel, for example through pixel areas 108 or 108'. Light passing through the display encounters a succession of optical active media: a polarizer, then liquid crystal material, and then another polarizer. At the juncture or seam 104 of two tiles, light which enters a pixel area adjacent to the seam 104 at large off-normal angles passes through the seam area between the tiles, avoiding the liquid crystal material, and exits the display through a pixel area in the adjacent tile, thereby making the seam 104 visible to the viewer. The collimating lattice 14 of this invention prohibits light that is beyond the desired off-normal angle from entering the display. The resultant effect is that pixel 110 has the same appearance (illumination level) as pixel 110' and pixel 108 has the same appearance as 108' when the target pixel 102 is illuminated. It is desired to have light which enters the display behind the target pixel 102, pass through only the target pixel's optically active (i.e., liquid crystal) media, and exit to the viewer only in the area defined by the target pixel 102. In practice this rarely happens. Some light from adjacent pixel areas 106, 108, 110, etc. enters the target pixel 102 and exits the display through other adjacent pixel areas 106, 108, 110, etc. In addition, light entering the target pixel area 102 also exits through adjacent pixel areas 106, 108, 108', 110'. This bleeding effect limits the actual resolution of the display. The viewer is not able to discriminate individual pixels if too much stray light (light beyond the desired cut-off angle) illuminates the rear of the display. An image viewed on a display with too much stray light is perceived as out of focus compared to the same image viewed on a display with less stray light. In other words, an image viewed on a display without excessive stray light is perceived as sharper than an image viewed on a display with excessive stray light. Referring now to FIG. 5, an alternative apparatus and method for producing light for a LCD display are shown, generally at reference numeral 120. This method is based on edge lighting a wave guide 122 with small diameter fluorescent lamps 18. Waveguide 122 is made of an optically clear material such as acrylic, glass, or polycarbonate. A collimating sheet 124 is bonded to the top of wave guide 122 using an optically transmissive adhesive having a suitable index of refraction such as acrylic adhesive or clear silicone adhesive. Collimating sheet 124 typically comprises arrays of Fresnel-type lenses and works on the principle of total internal reflection. The light produced by such a light source assembly 18, 122, 124 is collimated, but not sufficiently for a tiled, flat-panel display 16 to appear sharp and seamless. The addition of a collimating lattice 14 used in conjunction with this type of light source assembly does provide the necessary degree of collimation. The desired collimation angle can be calculated from a consideration of the display pixel geometry and mask geometry within display 16. The collimating lattice 14 is selected by choosing a ratio of lattice cell width W 32, 42 or 52 to lattice cell depth H 130, equal to the tangent of the desired collimation or cut-off angle. The collimating lattice 14 must be placed a sufficient distance, D 132, behind the display so that the shadow of the cell geometry itself is not imaged (i.e., projected or shadowed) onto display 16. A typical tiled display 16 may dictate a collimation angle of 25 degrees off-normal. The lattice is then selected with a height H 130 equal to twice the cell width W. A larger ratio may also work, but can result in discarding more of the available visible light energy than is necessary. The collimating lattice 14 must be placed at a distance of at least D 132 from the display 16 greater than twice the cell height H 130 in order to avoid imaging the lattice 14 by the display 16 in this example. Typically, the ratio of the lattice cell width W to cell height H 130 is the same as the ratio of the cell height H 130 to lattice-to-display distance D 132. There is no required relationship between the pixel pitch or spacing, not shown, in display 16 and the collimating lattice 14 cell dimensions. Since other modifications and changes varied to fit a particular operating requirements and environment will be apparent to those skilled in the art, the invention is not considered limited to the example chosen for purposes of disclosure, and covers all changes and modifications which do not constitute a departure from the true spirit and scope of the invention. Having thus described the invention, what is desired to be protected by Letters Patent is presented in the subsequent appended claims.

The present invention features an apparatus and method for collimating light for use with a tiled, flat-panel display having a seamless appearance (i.e., having visually imperceptible seams). A novel, multi-cell, collimation lattice is placed behind the bottom mask of the tiled, flat-panel display assembly, but in front of an illumination source. The lattice is formed from a thin, non-reflective material, so that the acceptable light passing through the lattice is not "blocked", but the unwanted (off-axis) light impinges upon the lattice cell walls and is absorbed.

BACKGROUND OF INVENTION [0001] Oil-based sludges of various types and consistencies are commonly generated as waste streams during oil or other hydrocarbon production processes. These sludges arise during well tests and initial production, as a by-product waste stream of hydrocarbon production, and as tank bottom sediments. The basic components of sludges are hydrocarbon oils of various consistencies, water, and solids of an inorganic and organic nature. Oil-based sludge typically refers to a complex water-in-oil emulsion stabilized by salts of organic compounds and fine solids. The oil phase contains a complex mixture of hydrocarbons of various consistencies including waxes and asphaltenes which may be solid or semi-solid at ambient temperature. [0002] The chemistries of oil-based sludges and the relative proportions of the oil, water, and solid phases of sludges vary greatly and can change over time. To dispose of the waste, sludge is often stored in open pits where it may be left for considerable time before being treated. During such aging periods, the sludge or “pit sludge” undergoes overall chemical composition changes due to the effects of weathering, including: volatilization of lighter hydrocarbons; temperature induced crosslinking of hydrocarbons; addition of rain water; and, invariably, the introduction of a variety of other contaminants, particulates, and debris. In addition to a variable complex chemistry, oil-based sludge typically has a high solids content. Sludge solids normally include both high density and low density solids. High density solids, i.e., high gravity solids, may be large solids introduced into the drilling fluid during the drilling of a formation (e.g. formation solids, drill bits, etc.) or other solids that are relatively dense such as barite or hermatite. While low density solids, i.e., low gravity solids, are those solids within the sludge that have a lower density or are relatively small fine solids (e.g., entrained solids such as sand). [0003] Currently, treatment of sludge is a major operational cost for producers. Sludge is collected, stored, and then disposed of in tanks or delivered to a sludge pit. One challenge of sludge treating systems is that the recovery of marketable oil from the sludge is generally not cost-effective and thus not commercially viable. Due to wide variability in sludge composition, different sludge processing systems may be needed to optimize the processing of sludge for recovering oil of sufficient quality in a cost efficient manner. The quality of oil is frequently characterized by its Basic Sediment and Water (BS&W) content, in vol. %. The current marketable BS&W of recovered oil is less than about 2 vol. %. Furthermore, it is desirable to treat pit sludge to reduce the risk of contamination of the surrounding pit area, in accordance with increasingly strict environmental regulations, as well as decrease the overall waste volume, and ultimately to permit pit closure. SUMMARY [0004] The present invention is generally directed to a modular oil-based sludge separation and treatment apparatus that is easily adapted to provide processing flexibility in order to ensure quality oil recovery from oil-based sludge in an efficient and cost-effective manner. The modular approach allows the configuration of processing equipment to be adapted to the oil-recovery processing requirements of the particular oil-based sludge composition. Providing a customizable apparatus maximizes the quantity and quality of the recovered oil while minimizing the processing time and cost to the operator. [0005] It is an objective of the present invention to provide a modular apparatus having certain processing equipment mounted on portable skids that are adaptable and versatile to permit customized arrangement for oil-recovery processing of a wide range of oil-base sludge compositions in a cost-efficient manner. [0006] In one aspect, the invention is directed to a modular apparatus for recovering oil from oil-based sludge having a high concentration of low density solids. The modular apparatus includes: a pumping skid having a pump operable to homogenize an oil-based sludge; a shaker skid having a screen that removes particulates from the oil-based sludge as the sludge traverses the screen to form a debris-free sludge; a heating skid shaving a heat exchanger operable to heat the debris-free sludge as: the debris-free sludge flows through the heat exchanger to form a heated sludge; a chemical skid having at least one chemical injection mixer operable to inject a chemical into the heated sludge and mix the chemical with the heated sludge to form a chemically-treated sludge; a phase separator skid having a three-phase separator operable to separate the phases of the chemically-treated sludge to form a first solids component stream, a first water component stream, a first oil component stream, and a first gas component stream; a decanter skid having a decanter centrifuge operable to remove solids from the first oil component stream to form a second solids component stream and a second oil component stream; and an oil purification skid having a disk stack centrifuge operable to remove water and solids from the second oil component stream to form a third solids component stream, a second water component stream, and a third oil component stream. [0007] In another aspect, the invention is directed to a modular apparatus for recovering oil from oil-based sludge having a high concentration of high density solids. The modular apparatus includes: a pumping skid: having a pump operable to homogenize an oil-based sludge; a shaker skid having a screen that removes particulates from the oil-based sludge as the sludge traverses the screen to form a debris-free sludge, a heating skid having a heat exchanger operable to heat the debris-free sludge as the debris-free sludge flows through the heat exchanger to form a heated sludge; a first chemical skid having at least one chemical injection mixer operable to inject a chemical into the heated sludge and mix the chemical with the heated sludge to form a first chemically-treated sludge: a decanter skid having a decanter centrifuge operable to remove solids from the first chemically-treated sludge to form a first solids component stream and a decanter-processed sludge; a second chemical skid having at least one chemical injection mixer operable to inject a chemical into the decanter-processed sludge and mix the chemical with the decanter-processed sludge to form a second chemically-treated sludge; a phase separator skid having a three-phase separator operable to separate the phases of the second chemically-treated sludge to form a second solids component stream, a first water component stream, a first oil component stream, and a first gas component stream; and an oil purification skid having a disk stack centrifuge operable to remove water and solids from the first oil component stream to form a third solids component stream, a second water component stream, and a second oil component stream. [0008] In still another aspect, the invention is directed to a modular apparatus for recovering oil from oil-based sludge having very low solids content. The modular apparatus includes: a pumping skid having a pump operable to homogenize an oil-based sludge; a shaker skid having a screen that removes particulates from the oil-based sludge as the sludge traverses the screen to form a debris-free sludge; a heating skid having a heat exchanger operable to heat the debris-free sludge as the debris-fee sludge flows through the heat exchanger to form a heated sludge; a chemical skid having at least one chemical injection mixer operable to inject a chemical into the heated sludge and mix the chemical with the heated sludge to form a chemically-treated sludge; a phase separator skid having a three-phase separator operable to separate the phases of the chemically-treated sludge to form a first solids component stream, a first water component stream, a first oil component stream, and a first gas component stream; and an oil purification skid having a disk stack centrifuge operable to remove water and solids from the first oil component stream to form a second solids component stream, a second water component stream, and a second oil component stream. [0009] These and other features are more fully set forth in the following description of preferred or illustrative embodiments of the disclosed and claimed subject matter. BRIEF DESCRIPTION OF THE DRAWINGS [0010] So that the manner in which the above recited features, advantages and objects of the present invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the embodiments thereof which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. [0011] FIG. 1 is a flow chart depicting a modular skid arrangement optimized for recovering the valuable hydrocarbon component of pit sludge having a high concentration of low density solids, according to an embodiment of the invention; [0012] FIG. 2 is a flow chart depicting another modular skid arrangement optimized for recovering the valuable hydrocarbon component of pit sludge having a high concentration of high density solids, according to another embodiment of the invention; [0013] FIG. 3 is a flow chart depicting still another modular skid arrangement optimized for recovering the valuable hydrocarbon component of pit sludge having very low solids content, according to still another embodiment of the invention; [0014] FIGS. 4 and 5 are schematics of an exemplary modular apparatus for separating and treating an oil-base sludge having a high concentration of low density solids to recover the valuable hydrocarbon component, in accordance with the skid arrangement shown in FIG. 1 ; [0015] FIGS. 4 and 6 are schematics of an exemplary modular apparatus for separating and treating an oil-base sludge having a high concentration of high density solids to recover the valuable hydrocarbon component, in accordance with the skid arrangement shown in FIG. 2 ; and [0016] FIGS. 4 and 7 are schematics of an exemplary modular apparatus for separating and treating an oil-base sludge having very low solids content to recover the valuable hydrocarbon component, in accordance with the skid arrangement shown in FIG. 3 . DETAILED DESCRIPTION [0017] The claimed subject matter relates to a modular apparatus having one of several skid arrangements depicted in FIGS. 1-3 for recovering the valuable hydrocarbon component of oil-based sludges having a wide variability in sludge composition. Depending upon the particular sludge composition and its solids content, the skid arrangements of the modular apparatus of the present invention may be easily configured, and re-configured, in order to optimize the separation and purification of the recovered oil while minimizing the time and cost to an operator. [0018] According to an embodiment of the invention, FIG. 1 depicts the skid arrangement: of a modular apparatus 100 optimally configured for recovering the valuable hydrocarbon component of sludge 14 initially having a high concentration of low density solids, Modular apparatus 100 comprises a pumping skid 102 , a shaker skid 104 , a heating skid 106 , a chemical skid 108 , a phase separator skid 110 , a gas purification skid 112 , a decanter skid 114 , and an oil purification skid 116 . Each of the skids 102 - 116 are described in more detail in the description that follows with respect to the modular apparatus 100 schematically illustrated in FIGS. 4 and 5 . [0019] As illustrated in FIGS. 4 and 5S modular apparatus 100 processes pit sludge through the pumping skid 102 , the shaker skid 104 , the heating skid 106 , the chemical skid 108 , the phase separator skid 110 , the gas purification skid 112 the decanter skid 114 , and the oil purification skid 116 . Referring to FIG. 4 , the pumping skid 102 includes a hydraulic submersible sludge pump 122 that homogenizes a pit sludge 10 contained in a pit 12 and then pumps a homogenized sludge 14 to the shaker skid 104 . The pump 122 may be mounted on a hydraulic arm in order to reach inner areas of the pit 12 . During ageing, the pit sludge 10 separates into basically three layers or phases, wherein the top layer of the pit is an oil-rich phase, the middle layer of the pit sludge 10 is a water-rich phase, and the bottom layer of the pit sludge 10 is a solids-rich phase. The pump 122 forms a homogeneous mixture or slurry of the three phases contained within the pit in order to provide a generally constant feed composition to the remainder of the apparatus 100 for processing. [0020] The shaker skid 104 includes a shaker screen 124 and a holding tank 126 mounted thereon and within the confines of the area in the skid 104 so as to maintain portability of the skid 104 . The shaker screen 124 physically separates and removes large particulates such as stones or debris from the sludge 14 . A debris-free sludge 16 exiting the shaker screen 124 collects in the holding tank 126 . Holding tank 126 may be essentially any type of tank that can contain a sufficient amount of sludge to supply and maintain a constant sludge flow rate to a heat exchanger 130 . A first transfer pump 128 in fluid communication with the holding tank 126 transfers the sludge 16 from the holding tank 126 to the heating skid 106 . In a preferred embodiment, the holding tank 126 is an augured V-Tank coupled to the pump 128 which is VFD (variable frequency driver) controlled in order to automatically provide a steady state flow rate of the sludge 16 to the heat exchanger 130 . [0021] The heating skid 106 has the heat exchanger 130 , a steam boiler 132 , and a fuel tank 134 mounted thereon and within the confines of the area of the skid 106 so as to maintain the portability of the skid 106 . Sludge 16 is heated to a desired temperature as it travels through the heat exchanger 130 . Because oil-based sludges often include waxy hydrocarbons, heating advantageously melts the waxy hydrocarbons into liquid form and lowers the viscosity of the sludge 16 . Also, heating advantageously aids in breaking the emulsion (secondary phase) and promotes phase separation within the sludge 16 . Providing heat to the heat exchanger 130 is accomplished by use of the steam boiler 132 . The steam boiler 132 generates steam and circulates the steam to the heat exchanger 130 via a first steam line 136 and a second steam line 138 . The flow rate, pressure, and temperature of the steam entering the heat exchanger 130 via line 136 are controlled so as to provide adequate heat transfer to the sludge 16 as it flows through the heat exchanger 130 . A heated sludge 18 , having the desired temperature and viscosity, exits the heat exchanger 130 and is subsequently transferred to the chemical skid 108 . In one example, the type of heat exchanger 130 used is a spiral type heat exchanger, wherein sludge 16 flows through the heat exchanger 130 in a path separate from that of the steam, but adjacent to it such that heat from the steam is transferred to the sludge 16 . It is understood that other types of heat exchangers can be used without departing from the scope of this invention. [0022] Depending upon the particular sludge composition, the sludge 16 is heated to essentially any temperature sufficient to liquefy the sludge 16 and lower its viscosity. When the viscosity is lower, treatment chemicals may be more easily blended with the heated sludge 18 in downstream processing. Furthermore, when the sludge viscosity is lower, entrained solids are more easily released in downstream processing. The desired temperature of the heated sludge 18 and its corresponding rheological profile can be predetermined and optimized using a viscometer, such as an oilfield Fann 35 viscometer available from Fann Instrument Co. In one example, sludge 18 is heated to a temperature in the range from about 65° C. to about 85° C. to sufficiently liquefy the sludge 18 and reduce its viscosity for downstream processing. More preferably, sludge 18 is heated to a temperature in the range from about 70° C. to about 80° C. Although it is desirable to heat the sludge 16 , care should be taken to ensure that the temperature of the heated sludge 18 is lower than the flash point temperature of the sludge 16 . The flash point is that minimum temperature at which there is enough evaporated fuel in the air to start combustion. The flash point of the sludge 16 can be determined by the use of a flash-point measuring device such as the Pensky Martens Closed Cup according to method ASTM D93B. [0023] Preferably, the fuel tank 134 is co-located on the skid 106 to provide fuel to the steam boiler 132 for heating the steam. Optionally, a power supply (not shown) is provided on the skid 106 to actuate valves (not shown) that regulate the flow rate of the steam through the first and second steam lines 136 , 138 , and also regulate the flow rates of the water supply and the fuel provided to the steam boiler 132 . A control panel (not shown) may be co-located on the skid 106 to monitor and automatically control the valves in order to automate the heating process at the heat exchanger 130 . In addition, the boiler 132 , flow lines 136 , 138 , and heat exchanger 130 are preferably thermally insulated to better maintain temperature uniformity and control. [0024] Once heated, the sludge 18 is transferred to a chemical skid 108 for chemically altering the sludge 18 to break up the emulsion and promote phase separation. The chemical skid 108 includes a plurality of chemical injection mixers 140 a - d and chemical supply tanks 142 a - d mounted thereon and within the confines of the area of the skid 108 so as to maintain the portability of the skid 108 . Chemical addition is typically required to destabilize the emulsion and change such properties to enhance separation of the water and solids from the sludge 18 , as well as decrease the separation: time required. Each of the chemical injection mixers 140 a - d includes a static shear mixer having an injection point. The injection point introduces a chemical into the sludge 18 while the mixer simultaneously blends the chemical and the sludge 18 under the shearing action of the mixer. The chemical injection mixer advantageously provides a homogeneous distribution of the chemical within the sludge 18 to aid in its complete and efficient chemical reaction therein. As depicted in FIG. 5 , four chemicals are added to the heated sludge 18 as the sludge is directed through the chemical injection mixers 140 a - d . Each of the chemical injection mixers 140 a - d has a corresponding chemical supply tank 142 a - d for storing the chemicals until they are transferred via chemical lines 144 a - d to the mixers 140 a - d for injection into the sludge 18 . Once all the chemicals are introduced and blended into the heated sludge 18 , a chemically-treated sludge 20 exits the last chemical injection mixer 140 d and is subsequently transferred to the phase separator skid 110 for further processing. [0025] Depending upon the particular initial sludge 14 composition, a wide variety of chemicals, may be introduced and blended into the sludge 18 in order facilitate subsequent processing to separate the solid, water, and oil phases of the chemically treated sludge 20 . Suitable chemicals include acids, demulsifiers, wetting agents, surfactants, flocculants, and defoamers. Demulsifiers modify the interfacial tension of the emulsion film to release the water and assist in separating out the water from the oil. Wetting agents alter the wetability of solid particles thereby causing the solid particles to become hydrophilic which increases the solids affinity for water and causes further breakup of the interfacial emulsion film. Flocculants induce the solids to aggregate and form larger solids to facilitate separation of the solids in the sludge. In one example, as the heated sludge 18 travels through the first injection mixer 140 a , the mixer 140 a injects an acid and blends the acid with the sludge 18 therein in order to neutralize adsorbed ions present at the interfacial emulsion film of the sludge 18 and chemically prepare the sludge 18 for chemical treatment with a demulsifier. Subsequently, the sludge 18 is directed through the second injection mixer 140 b wherein a demulsifier is injected and blended into the sludge 18 to break the interfacial emulsion film for release of the secondary water phase. The sludge 18 then passes through the third injection mixer 140 c wherein a wetting agent is injected and blended into the sludge to alter the affinity of the solids towards the water phase. Afterwards, the sludge 18 passes through the fourth injection mixer 140 d wherein a defoamer is injected and blended into the sludge for the purpose of counteracting surfactants (detergents) present in the sludge that may otherwise undesirably cause foaming. After chemical treatment in injection mixers 140 a - d , a chemically-treated sludge 20 exits the chemical skid 108 and is ready for subsequent processing. It should be noted that the present invention is not intended to be limited to the use of any particular chemicals, and other chemicals may be substituted for any of the aforementioned chemicals. [0026] Furthermore, additional chemicals may be incorporated into the sludge 18 by providing additional injection mixers (e.g., 140 e - n ) on the skid 108 such that all the desired chemicals may be introduced into the sludge. For example, a fifth injection mixer (not shown) may be included on skid 108 to introduce a pour point suppressant into the sludge 18 in order to extend the fluidity of the sludge to lower temperatures. Because wax in the sludge can cause issues for pumping and phase separation in terms of the high viscosity it imparts and coating of entrained solids, pour point suppressants can be added to depress the temperature at which wax molecules in the oil phase of the sludge 18 solidify, Conversely, in another example, fewer chemicals may be incorporated into the sludge 18 by bypassing one or more of the injection mixers 140 a - d or, alternatively, removing one of more of the mixers 140 a - d from the skid 108 . [0027] Preferably at least one dosing pump (not shown) in fluid communication with each of the chemical injection mixers 140 a - d is used to provide a predetermined quantity of chemical to the injection point of the mixer for introduction into the sludge 18 . The quantity of each of the chemicals introduced into the sludge 18 depends upon the particular initial sludge composition 14 . For example, a dosing pump in fluid communication with the second injection mixer 140 b provides demulsifier in the predetermined amount of 2-3% by volume of sludge 18 . Although essentially any type of dosing pump may be used, in one example each of the dosing pumps is a gear pump with a VFD control panel. In addition, preferably, the chemical injection mixers 140 a - d are thermally insulated to better maintain the sludge temperature and fluidity. [0028] After chemical treatment, the sludge 20 is directed to the phase separator skid 110 for separating the solid, water, oil, and gas phases of the sludge 20 . The phase separator skid 110 includes a surge tank 146 and a three-phase separator 148 mounted thereon and within the confines of the area of the skid 110 so as to maintain the portability of the skid 110 . The sludge 20 is fed into the vertically-oriented surge tank 146 which separates heavier solids from the sludge 20 and provides a continuous flow of a liquid portion of the sludge 22 to the three-phase separator 148 . The surge tank 146 contains an interior plate that facilitates the small solids (e.g., solids in suspension) within the sludge 20 to aggregate and form larger solids such that gravity is sufficient to separate these heavier solids out of the sludge 20 . Separated solids 24 that settle and accumulate in a bottom region of the surge tank 146 are discharged and directed to a solids receiving tank 150 . The liquid portion of the sludge 22 , which comprises oil, water, gas, and fine solids, is directed to the three-phase separator 148 . [0029] The liquid portion of the sludge 22 flows into the three-phase separator 148 through an inlet located at one end of the separator 148 . The separator 148 is designed to separate the phases and flow the separated phases to their respective outlets. Within the retention section of the three-phase separator 148 , the liquid portion of the sludge 22 separates into a water-rich phase 28 , an oil-rich phase 30 , and a gas phase 44 . Furthermore, additional solids 26 that may settle out of the sludge 22 and accumulate in a bottom region of the separator 148 , primarily as a result of the re-distribution or separation of the phases, are discharged and directed to the solids receiving tank 150 . The water-rich phase 28 is discharged to a water tank 152 . The oil-rich phase 30 is transferred to the decanter skid 114 for fine solids removal. The gas phase 44 is directed to the gas purification skid 112 to clean the gas for release into the atmosphere. One exemplary three-phase separator 148 is the Horizontal Longitudinal Flow Separator commercially available from NATCO Group Inc., Houston, Tex. However, the present invention is not limited to a particular type of surge tank or three-phase separator. In addition, the surge tank 146 and three-phase separator 148 are both preferably insulated to better maintain the sludge temperature and fluidity. [0030] The oil-rich phase 30 is transferred to the decanter skid 114 to separate the fine solids out of the oil-rich phase 30 . The decanter skid 114 includes a decanter centrifuge 154 and a heating tank 156 mounted thereon and within the confines of the area of the skid 114 so as to maintain the portability of the skid 114 . For the removal of solids, the decanter centrifuge 154 is particularly useful in reducing the solids content in liquids having a solids concentration in excess of about 3 vol. % to a solids concentration less than about 2 vol. %. Once the oil-rich phase 30 is fed into the decanter centrifuge 154 , centrifugal force causes suspended solids to separate out of the oil-rich phase 30 and coalesce for subsequent removal from the decanter, Solids 32 are discharged through a solids outlet located in the bottom of the decanter centrifuge 154 . At this point in the processing, a decanter-processed oil-rich phase 34 that exits the decanter 154 has a BS&W of less than about 2 vol. %. Suitable decanter centrifuges include decanter centrifuges having a rotational speed of 3000 rpm or greater. Exemplary decanter centrifuges include Model 500 (3000 rpm) and Model 518 (5000 rpm) commercially available from M-I L.L.C., Houston, Tex. [0031] After the fine solids removal, the decanter-processed oil-rich phase 34 is transferred to the heating tank 156 and optionally heated therein. Because a significant amount of cooling can occur during the various prior processing steps, since being previously heated in the heat exchanger 130 , the oil-rich phase 34 is optionally heated to a desired temperature in the heating tank 156 in order to enhance its final phase separation and purification during the next processing step at the oil purification skid 116 . The heating tank 156 includes a heating element (e.g., a steam coil) capable of heating the contents of the tank 156 . After heating, a heated oil-rich phase 36 is pumped via a second transfer pump 158 to the oil purification skid 116 for final purification. In one example, the heated oil-rich phase 36 is heated to a temperature in the range from about 65° C. to about 85° C. [0032] The heated oil-rich phase 36 is transferred to the oil purification skid 116 for its final purification and recovery of oil therefrom having a BS&W of less than about 1 vol. %. The oil purification skid 116 includes a disk stack centrifuge 160 . As depicted in FIG. 5 , the heated oil-rich phase 36 is fed into the disk stack centrifuge 160 to further purify the oil. The disk stack centrifuge uses a combination of plates (i.e., the disk stack) and extremely high centrifugal forces to separate the very fine water emulsion and the ultra-fine solids out of the oil-rich phase 36 . After separation, a water stream 38 , a recovered oil stream 40 , and an ultra-fine solids phase 42 are discharged from the centrifuge 160 . After final processing in the disk stack centrifuge 160 , the recovered oil stream 40 has a BS&W less than about 1 vol. % and is commercially marketable. Exemplary disk stack centrifuges are commercially available from Alfa Lavel Inc., Richmond, Va. [0033] The gas phase 44 is transferred to the gas purification skid 112 where the gas phase 44 is treated to remove volatile organic compounds (VOCs) prior to discharge into the environment. The gas purification skid 112 preferably includes a free water knockout pot 162 , at least one mist impinger 166 , and at least one activated carbon filter 168 mounted thereon and within the confines of the area of the skid 112 so as to maintain the portability of the skid 112 . A VFD-controlled vacuum blower 164 attached to the knockout pot 162 is used to draw the gas phase 44 from a gas vent located in an upper side of the three-phase separator 148 through the knockout pot 162 filled with water. The gas phase 44 enters a gas inlet located near the bottom of the knockout pot 162 , and hydrocarbons in the gas phase 44 adhere to the water as the gas travels upwardly through the pot 162 . Water in the knockout pot 162 is periodically emptied into a liquid waste disposal and replaced with fresh water. Because the exiting gas is saturated with water, a wet-gas 46 that exits a gas outlet near the top of the knockout pot 162 is directed through at least one mist impinger 166 to remove water from the gas 46 and provide a dry gas 48 . The dry gas 48 that exits the at least one mist impinger 166 is then transferred to an activated carbon filter 168 to remove contaminants (e.g., remaining VOCs) therefrom in order to ensure a gas 50 that meets the environmental regulatory standards for release to the atmosphere. In one example, as depicted in FIG. 5 , the knockout pot 162 removes hydrocarbons from the gas phase 44 , and afterwards the exiting wet-gas 46 is directed through two mist impingers 166 to adequately dry the gas prior to directing the dry gas 48 through one or more activated carbon filters 168 . When the activated carbon filter 168 becomes exhausted, it may be treated to reactivate the carbon or, alternatively, may be disposed of according to appropriate regulatory procedures. [0034] According to another embodiment of the invention, FIG. 2 depicts the skid arrangement of a modular apparatus 200 optimally configured for recovering the valuable hydrocarbon component of sludge 14 initially having a high concentration of high density solids. In FIG. 2 the same reference numerals are used to indicate the same skids as those previously described with respect to the apparatus 100 depicted in FIG. 1 . Modular apparatus 200 comprises the pumping skid 1025 the shaker skid 104 , the heating skid 106 , a first chemical skid 118 , the decanter skid 114 , a second chemical skid 120 , the phase separator skid 110 , the gas purification skid 112 , and the oil purification skid 116 . In this embodiment, two chemical skids 118 , 120 are utilized with the decanter skid 114 positioned between the chemical skids 118 , 120 . For sludge 14 initially having a high concentration of high density solids, it is preferable to remove solids from the sludge using a decanter centrifuge prior to delivery of all the chemicals during the chemical treatment of the sludge. Skids 118 and 120 are described in more detail in the description that follows with respect to the modular apparatus 200 schematically illustrated in FIGS. 4 and 6 . [0035] Illustrated in FIGS. 4 and 6 , modular apparatus 200 processes pit sludge through the pumping skid 102 , the shaker skid 104 , the heating skid 106 , the first chemical skid 118 , the decanter skid 114 , the second chemical skid 120 , the phase separator skid 110 , the gas purification skid 112 , and the oil purification skid 116 . As previously described with respect to FIG. 4 the modular apparatus 200 processes pit sludge 10 through the pumping skid 102 , the shaker skid 104 , and the heating skid 106 to provide a heated sludge 18 . [0036] Referring now to FIG. 6 , the heated sludge 18 is transferred to the first chemical skid 118 for chemically altering the sludge 18 to break up the emulsion and promote solids separation. In FIG. 6 the same reference numerals are used to indicate the same features as those previously described with respect to apparatus 100 depicted in FIG. 5 . The chemical skid 118 includes a plurality of chemical injection mixers 140 a , 140 b and chemical supply tanks 142 a , 142 b mounted thereon and within the confines of the area of the skid 118 so as to maintain the portability of the skid 118 . Chemical addition is typically required to destabilize the emulsion and change such properties to facilitate separation of the solids from the sludge 18 and decrease the separation time required. Each of the chemical injection mixers 140 a , 140 b includes a static shear mixer having an injection point for introducing a chemical into the sludge 18 while the mixer simultaneously blends the chemical and the sludge 18 under the shearing action of the mixer. As illustrated in FIG. 6 , two chemicals are added to the heated sludge 18 as the sludge is directed through the chemical injection mixers 140 a , 140 b . Chemical supply tanks 142 a , 142 b store the chemicals until they are transferred via chemical lines 144 a , 144 b to the mixers 140 a , 140 b for injection into the sludge 18 . Preferably at least one dosing pump (not shown) in fluid communication with each of the chemical injection mixers 140 a , 140 b is used to provide a predetermined quantity of chemical to the injection point of the mixer for introduction into the sludge 18 . In addition the chemical injection mixers 140 a , 140 b are preferably insulated to better maintain the sludge temperature and fluidity. Once the chemicals are introduced and blended into the heated sludge 18 , a first chemically-treated sludge 202 exits the last chemical injection mixer 140 b and is subsequently transferred to the decanter skid 114 to separate the high density solids out of the first chemically-treated sludge 202 . It should be noted that additional chemical injection mixers may be added to the first chemical skid 118 for the introduction of additional chemicals into the sludge 18 . [0037] Depending upon the particular initial sludge 14 composition, a wide variety of chemicals may be introduced and blended into the sludge 18 in order facilitate subsequent processing to separate the solids out of the first chemically-treated sludge 202 . Suitable chemicals include acids, demulsifiers, wetting agents, surfactants, flocculants, and defoamers. In one example, as the heated sludge 18 travels through the first injection mixer 140 a , the mixer 140 a injects an acid and blends the acid with the sludge 18 therein in order to neutralize adsorbed ions present at the interfacial emulsion film of the sludge 18 . Subsequently, the sludge 18 is directed through the second injection mixer 140 b wherein a wetting agent is injected and blended into the sludge to alter the affinity of the solids towards the water phase. It should be noted that the present invention is not intended to be limited to the use of any particular chemicals, and other chemicals may be substituted for any of the aforementioned chemicals. [0038] The first chemically-treated sludge 202 is directed to the decanter skid 114 for solids removal. The chemically-treated sludge 202 entering the decanter skid 114 can have a solids content as high as in the range of 6 vol. % to 15 vol. %. As previously described, the decanter skid 114 includes a decanter centrifuge 154 and a heating tank 156 mounted thereon and within the confines of the area of the skid 114 . The decanter centrifuge 154 is used to reduce the solids content in the sludge 202 to a solids concentration less than about 2 vol. %. In the decanter centrifuge 154 , centrifugal force causes solids 204 to separate out of the sludge 202 and coalesce for subsequent removal from the decanter through a solids outlet located in the bottom of the decanter centrifuge 154 . A decanter-processed sludge 206 that exits the decanter centrifuge 154 has a solids content of less than about 2 vol. %. As previously described, suitable decanter centrifuges include decanter centrifuges having a rotational speed of 3000 rpm or greater. [0039] After reducing the solids in the sludge 206 , the decanter-processed sludge 206 is transferred to the heating tank 156 and optionally heated therein. Because a significant amount of cooling can occur during the previous processing steps since being heated in the heat exchanger 1301 the decanter processed sludge 206 may be heated to a desired temperature in the heating tank 156 in order to lower its viscosity and facilitate blending of additional chemicals into the sludge 206 during the next processing step at the second chemical skid 120 . After heating, a heated decanter-processed sludge 208 is pumped via the second transfer pump 158 to the second chemical skid 120 . In one example, the heated decanter-processed sludge 208 is heated to a temperature in the range from about 65° C. to about 85° C. [0040] The heated decanter-processed sludge 208 is transferred to the second chemical skid 120 for chemically altering the sludge 208 to further break up the emulsion and promote phase separation. The chemical skid 120 includes a plurality of chemical injection mixers 140 c , 140 d and chemical supply tanks 142 c , 142 d mounted thereon and within the confines of the area of the skid 120 so as to maintain the portability of the skid 120 , Chemical addition is typically required to further destabilize the emulsion and change such properties to enhance oil-water-solids phase separation during the next processing steps at the phase separator skid 110 . Each of the chemical injection mixers 140 c , 140 d includes a static shear mixer having an injection point for introducing a chemical into the sludge 208 . As illustrated in FIG. 6 , two chemicals are added to the sludge 208 as the sludge travels through mixers 140 c , 140 d . Chemical supply tanks 142 c , 142 d store the chemicals until they are transferred via chemical lines 144 c , 144 d to the mixers 140 c , 140 d . Preferably at least one dosing pump (not shown) in fluid communication with each of the chemical injection mixers 140 c , 140 d is used to provide a predetermined quantity of chemical to the injection point of the mixer for introduction into the sludge 208 . In addition, the chemical injection mixers 140 c , 140 d are preferably insulated to better maintain the sludge temperature and fluidity. Once the chemicals are introduced and blended into the sludge 208 , a second chemically-treated sludge 210 exits the last chemical injection mixer 140 d and is subsequently transferred to the phase separator skid 110 . It should be noted that additional chemical injection mixers may be added to the second chemical skid 120 for the introduction of additional chemicals into the sludge 208 . [0041] Depending upon the particular sludge 208 composition, a wide variety of chemicals may be introduced and blended into the sludge to promote separation of the water, oil, and solid phases of the second chemically-treated sludge 210 . Suitable chemicals include acids, demulsifiers, wetting agents, surfactants, flocculants, and defoamers. In one example, as the sludge 208 travels through the third injection mixer 140 c , the mixer 140 c injects a demulsifier into the sludge 208 to break the interfacial emulsion film to release the secondary water phase. Afterwards, the sludge 208 is directed through the fourth injection mixer 140 d wherein a defoamer is injected and blended into the sludge for the purpose of preventing foaming. Again, it should be noted that the present invention is not intended to be limited to the use of any particular chemicals, and other chemicals may be substituted for any of the aforementioned chemicals. Furthermore, additional chemical injection mixers may be added to the second chemical skid 120 for the introduction of additional chemicals into the sludge 208 . [0042] After the second chemical treatment, the sludge 210 is directed to the phase separator skid 11 for separating water and solids from the oil phase of the sludge 210 . As previously described, the phase separator skid 110 includes a surge tank 146 and a three-phase separator 148 mounted thereon. The sludge 210 is fed into the vertically-oriented surge tank 146 which separates solids from the sludge 210 and provides a continuous flow of a liquid portion of the sludge 212 to the three-phase separator 148 . Separated solids 214 that settle and accumulate in a bottom region of the surge tank 146 are discharged to the solids receiving tank 150 . The liquid portion of the sludge 212 which comprises oil, water, gas, and fine solids is directed to the three-phase separator 148 . [0043] The liquid portion of the sludge 212 flows into the three-phase separator 148 through an inlet located at one end of the separator 148 . After phase separation within the retention section of the three-phase separator 148 , a water-rich phase 218 is discharged to a water tank 152 , an oil-rich phase 220 is transferred to the oil purification skid 116 , and a gas phase 228 is directed to the gas purification skid 112 . Any solids 216 that may settle out of the sludge 212 and accumulate in a bottom region of the separator 148 during separation of the phases are discharged to the solids receiving tank 150 . [0044] The oil-rich phase 220 is transferred to the oil purification skid 116 for final purification and recovery of oil therefrom having a BS&W of less than about 1 vol. %. As previously described, the oil purification skid 116 includes a disk stack centrifuge 160 mounted thereon. The oil-rich phase 220 is fed into the disk stack centrifuge 160 wherein extremely high centrifugal forces separate the very fine water emulsion and the ultra-fine solids out of the oil-rich phase 220 . After phase separation, a water stream 222 , a recovered oil stream 224 , and an ultra-fine solids phase 226 are discharged from the centrifuge 160 . The recovered oil stream 224 has a BS&W less than about 1 vol. % and is commercially marketable. [0045] The gas phase 228 is transferred to the gas purification skid 112 where the gas phase 228 is treated to remove VOCs prior to discharge into the environment. As previously described, the gas purification skid 112 preferably includes a free water knockout pot 162 , at least one mist impinger 166 , and at least one activated carbon filter 168 mounted thereon. A VFD-controlled vacuum blower 164 attached to the knockout pot 162 is used to draw the gas phase 228 from a gas vent located in an upper side of the three-phase separator 148 through the knockout pot 162 filled with water. Hydrocarbons in the gas phase 228 adhere to the water as the gas travels upwardly through the pot 162 . A wet-gas 230 that exits a gas outlet near the top of the knockout pot 162 is directed through at least one mist impinger 166 to remove water from the gas 230 and provide a dry gas 232 . The dry gas 232 is transferred to an activated carbon filter 168 to remove contaminants (e.g., remaining VOCs) therefrom in order to ensure a gas 234 that meets the regulatory standards for release to the atmosphere. [0046] According to still another embodiment of the invention, FIG. 3 depicts the skid arrangement of a modular apparatus 300 optimally configured for recovering the valuable hydrocarbon component of sludge 14 initially having a low concentration of solids. In FIG. 3 the same reference numerals are used to indicate the same skids as those previously described with respect to the apparatus 100 depicted in FIG. 1 . Modular apparatus 300 comprises the pumping skid 102 , the shaker skid 104 , the heating skid 106 , the chemical skid 108 , the phase separator skid 110 , the gas purification skid 112 , and the oil purification skid 116 . This embodiment excludes the use of the decanter skid 114 . For sludge 14 initially having a low concentration of solids, it may be unnecessary to include a decanter centrifuge for the removal of solids. [0047] Illustrated in FIGS. 4 and 7 , modular apparatus 300 processes pit sludge through the pumping skid 102 , the shaker skid 104 , the heating skid 106 , the chemical skid 108 , the phase separator skid 110 the gas purification skid 112 , and the oil purification skid 116 . As previously described with respect to FIG. 4 , the modular apparatus 300 processes pit sludge 10 through the pumping skid 102 , the shaker skid 104 , and the heating skid 106 to provide a heated sludge 18 . [0048] Referring now to FIG. 7 , the heated sludge 18 is transferred to the chemical skid 108 for chemically altering the sludge 18 to break up the emulsion and promote phase separation. In FIG. 7 the same reference numerals are used to indicate the same features as those previously described with respect to apparatus 100 depicted in FIG. 5 . As previously described, the chemical skid 108 includes a plurality of chemical injection mixers 140 a - d and chemical supply tanks 142 a - d mounted thereon. Chemical addition is typically required to destabilize the emulsion and change such properties of the sludge 18 to enhance the its phase separation during the next processing step at the phase separator skid 110 . As previously described, each of the chemical injection mixers 140 a - d includes a static shear mixer having an injection point for introducing a chemical into the sludge 18 while the mixer simultaneously blends the chemical and the sludge 18 under the shearing action of the mixer. As illustrated in FIG. 7 , four chemicals are added to the heated sludge 18 as the sludge is directed through the chemical injection mixers 140 a - d . Chemical supply tanks 142 a - d store the chemicals until they are transferred via chemical lines 144 a - d to the mixers 140 a - d for injection into the sludge 18 . Preferably at least one dosing pump (not shown) in fluid communication with each of the chemical injection mixers 140 a - d is used to provide a predetermined quantity of chemical to the injection point of the mixer for introduction into the sludge 18 . Preferably, chemical injection mixers 140 a - d are thermally insulated to better maintain the sludge temperature and fluidity. Once the chemicals are introduced and blended into the heated sludge 18 , a chemically-treated sludge 302 exits the last chemical injection mixer 140 d and is subsequently transferred to the phase separator skid 110 for separating the water, oil and solid phases of the sludge 302 . Again, it should be noted that additional chemical injection mixers may be added to the chemical skid 108 for the introduction of additional chemicals into the sludge 18 . [0049] After chemical treatment, the sludge 302 is directed to the phase separator skid 110 for separating water and solids from the oil phase of the sludge 302 . As previously described, the phase separator skid 110 includes a surge tank 146 and a three-phase separator 148 mounted thereon. The sludge 302 is fed into the vertically-oriented surge tank 146 which contains an interior plate that facilitates the small solids within the sludge to aggregate and form larger solids that settle out of the sludge 302 and accumulate in a bottom region of the surge tank 146 . Separated solids 306 that accumulate in the surge tank 146 are discharged to the solids receiving tank 150 . The surge tank 146 also provides a continuous flow of a liquid portion of the sludge 304 to the three-phase separator 148 for oil, water, gas, and solid phase separation. [0050] The liquid portion of the sludge 304 flows into the three-phase separator 148 through an inlet located at one end of the separator 148 . After phase separation within the retention section of the three-phase separator 148 , a water-rich phase 310 is discharged to a water tank 152 , an oil-rich phase 312 is transferred to the oil purification skid 116 , and a gas phase 320 is directed to the gas purification skid 112 . Any solids 308 that may settle out of the sludge 304 and accumulated in a bottom region of the separator 148 during separation of the phases are discharged to the solids receiving tank 150 . [0051] The oil-rich phase 312 is transferred to the oil purification skid 116 for final purification and recovery of oil therefrom having a BS&W of less than about 1 vol. %. As previously described, the oil purification skid 116 includes a disk stack centrifuge 160 mounted thereon. The oil-rich phase 312 is fed into the disk stack centrifuge 160 wherein extremely high centrifugal forces separate the very fine water emulsion and the ultra-fine solids out of the oil rich phase 312 . After phase separation, a water stream 314 , a recovered oil stream 316 , and an ultra-fine solids phase 318 are discharged from the centrifuge 160 . The recovered oil stream 316 has a BS&W less than about 1 vol. % and is commercially marketable. [0052] The gas phase 320 is transferred to the gas purification skid 112 where the gas phase 320 is treated to remove VOCs prior to discharge into the environment. As previously described, the gas purification skid 112 preferably includes a free water knockout pot 162 , at least one mist impinger 166 , and at least one activated carbon filter 168 mounted thereon. A VFD-controlled vacuum blower 164 attached to the knockout pot 162 is used to draw the gas phase 320 from a gas vent located in an upper side of the three-phase separator 148 through the knockout pot 162 filled with water. Hydrocarbons in the gas phase 320 adhere to the water as the gas travels upwardly through the pot 162 . A wet-gas 322 that exits a gas outlet near the top of the knockout pot 162 is directed through at least one mist impinger 166 to remove water from the gas 322 and provide a dry gas 324 . The dry gas 324 is transferred to an activated carbon filter 168 to remove contaminants (e.g., remaining VOCs) therefrom in order to ensure a gas 326 that meets the regulatory standards for release to the atmosphere. [0053] While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.

A modular apparatus having certain processing equipment mounted on portable skids that are adaptable and versatile to permit customized arrangement for oil-recovery processing of a wide range of oil-base sludge compositions in a cost-efficient manner. In one aspect, the invention is directed to a modular apparatus optimally configured for oil recovery of sludge having a high concentration of low density solids, wherein the apparatus may include a pumping skid, a shaker skid, a heating skid, a chemical skid, a phase separator skid, a gas purification skid, a decanter skid, and an oil purification skid. In another aspect, the invention is directed to a modular apparatus optimally configured for oil recovery of sludge having a high concentration of high density solids, wherein the apparatus may include a pumping skid, a shaker skid, a heating skid, a first chemical skid, a decanter skid, a second chemical skid, a phase separator skid, a gas purification skid, and an oil purification skid. In still another aspect, the invention is directed to a modular apparatus optimally configured for oil recovery of sludge having a very low solids content, wherein the apparatus may include a pumping skid, a shaker skid, a heating skid, a chemical skid, a phase separator skid, a gas purification skid, and an oil purification skid.

BACKGROUND OF THE INVENTION [0001] Leishmaniasis is a protozoan parasitic disease endemic in 88 countries, which causes considerable morbidity and mortality. At least 20 species of Leishmania can be transmitted by sandfly bites, originating cutaneous, diffuse cutaneous, mucocutaneous and visceral leishmaniasis in humans, dogs and various wild vertebrate hosts. The estimated yearly incidence is 1-1.5 million cases of cutaneous leishmaniasis and 500,000 cases of visceral leishmaniasis. The population at risk is estimated at 350 million people with an overall prevalence of 12 million. Increasing risk factors are making leishmaniasis a growing public health concern for many countries around the world. [0002] The drugs most commonly used to treat leishmaniasis are the pentavalent antimonials sodium stibogluconate (Pentostam) and meglumine antimonate (Glucantime). Antimonial chemotherapy requires high dose regimens with long treatment courses using parenteral administration. Second-line drugs, used in instances of antimonial-treatment failure, include amphotericin B (AMB), paromomycin (aminosidine), and pentamidine. However, all of these drugs are far from satisfactory due to unacceptable side effects at effective doses. The recently developed liposomal formulation of amphotericin B (AmBisome™) showed good curative rates for antimony unresponsive cases of mucocutaneous leishmaniasis however, drug administration is technically difficult and treatment costs are prohibitively expensive. [0003] The spreading resistance of the parasite towards the standby antimonial drugs, the high toxicity of most drugs in use, and the emergence of Leishmania /HIV co-infection as a new disease entity has triggered a continuous search for alternative therapies. Visceral leishmaniasis caused by L. infantum has emerged as an AIDS-associated opportunistic infection, particularly in southern Europe. [0004] In recent years, alkyllysophospholipid analogues (ALPs) have received considerable interest due to their antineoplastic and immunomodulatory properties. Extensive structure-activity relationship studies on a variety of ALPs showed that a long alkyl chain and a phosphocholine moiety may represent the minimal structural requirements for sufficient antineoplastic effects of ether lipid analogues. This finding led to the synthesis of the alkylphosphocholines (APCs). Within the alkyl chain homologs, hexadecylphosphocholine (HePC) has therapeutically useful antitumor activity and was approved in 1992 as a drug in Germany for the topical treatment of metastasized mammary carcinoma. [0005] Several in vitro and in vivo studies demonstrated that alkylphosphocholines including HePC, and alkylglycerophosphocholines such as edelfosine, ilmofosine and SRI-62,834 possess antileishmanial activity. Hexadecylphosphocholine was reported to be highly effective in treating mice infected with visceral leishmaniasis while oral treatment with miltefosine was 600-fold more effective than the subcutaneous administration of pentostam. On the basis of these promising observations HePC (miltefosine) was evaluated in phase I and II clinical trials as oral therapy for Indian visceral leishmaniasis while phase III clinical trials are currently ongoing. Cure rates of 88% to 100% were obtained using doses of 100-150 mg/day for 28 days. These results encouraged studies on the efficacy of miltefosine treatment for cutaneous leishmaniasis in the New World and currently phase II studies are being conducted. In a phase I study, the cure rate with miltefosine at doses of 100-150 mg for 3 weeks was 94%. In the various clinical trials, the main side effects associated with miltefosine were gastrointestinal with the most common being moderate vomiting and diarrhea. Transient elevation of transaminases or urea/serum creatinine was noted in a number of patients and decreased under continued treatment. Although the toxicity associated with miltefosine sounds milder than that of some parenteral therapies, gastrointestinal symptoms could be of more consequence in severely ill patients, such as those who are malnourished or dehydrated. In addition, treatment of pregnant women is contraindicated because of miltefosine's teratogenic properties in animals. Furthermore, miltefosine has a very long half-life and low therapeutic ratio and a course of treatment leaves a sub-therapeutic level in the blood for several weeks. These drug characteristics might be expected to encourage development of resistance. Additionally, miltefosine was shown to be only temporarily effective in HIV co-infected patients in Europe. Therefore, a need exists for new phospholipids in the treatment of protozoal diseases and especially leishmaniasis that will not cause significant adverse side effects. [0006] U.S. Pat. No. 5,436,234 discloses compounds of the general formula: R—X-A-PO 3 —(CH 2 ) 2 —N + R 1 R 2 R 3 Wherein R is a erucyl, brassidyl or nervonyl radical, R 1 , R 2 and R 3 are, independently of one another, straight-chained, branched or cyclic saturated or unsaturated alkyl radicals containing up to 4 carbon atoms, which can also contain a hydroxyl group, and wherein two of these radicals can also be connected together to form a ring, A is a valency bond or a radical of one of the formulae: And X is an oxygen atom when A is preferably a valency bond. Compounds of the general formula R-X-A-PO 3 —(CH 2 ) 2 —N + R 1 R 2 R 3 and pharmaceutical compositions containing them can be used for the treatment of protozoal and fungal diseases, autoimmune diseases and bone marrow damage. [0007] U.S. Pat. No. 6,254,879 which is continuation-in part of application Ser. No. 08/469,779 now U.S. Pat. No. 5,980,915 discloses a new pharmaceutical agent for oral or topical administration in the treatment of protozoal diseases, in particular of leishmaniasis which contains as the active substance one or several compounds of the general formula R 1 —PO 4 —CH 2 CH 2 —N + R 2 R 3 R 4 , in which R 1 is a saturated or monounsaturated or polyunsaturated hydrocarbon residue with 12 to 20 C atoms. [0008] U.S. Pat. No. 6,344,576 relates to phosphor-lipid compounds of formula (I) having solubilizing activity for water-insoluble or poorly water soluble active agents and their use in the delivery of active agents to cells and in the treatment of diseases, i.e. cancer and protozoal diseases. in which A where R 1 and R 2 are, independently of one another, hydrogen, a saturated or unsaturated acyl or alkyl radical which can optionally be branched or/and substituted, where the total of the carbon atoms in the acyl and alkyl is 16 to 44 C atoms. SUMMARY OF THE INVENTION [0009] One aspect of this invention pertains to novel ring containing phospholipids and use thereof in treating protozoal diseases such as leishmaniasis, trypanosomiasis, malaria, toxoplasmosis, babeosis, amoebic dysentery and lambliasis. The compounds of the present invention comprise phospholipids of the general formula A-X—PO 3 —W. [0010] Another aspect of this invention relates to a method of preparing said compounds. [0011] A further aspect of this invention relates to method for treating protozoal infections includes administering an effective infection-combating amount of a compound of the present invention in a therapeutic manner. [0012] A better understanding of the invention will be obtained from the following detailed description of the article and the desired features, properties, characteristics, and the relation of the elements as well as the process steps, one with respect to each of the others, as set forth and exemplified in the description and illustrative embodiments. BRIEF DESCRIPTION OF THE DRAWINGS [0013] FIG. 1 is a graph illustrating the percentage of live THP1 cells in the presence of a different concentrations of some inventive compounds. [0014] FIG. 2 illustrates some inventive compounds. [0015] FIG. 3 shows the hemolytic activity of selected examples with respect to miltefosine. DETAILED DESCRIPTION OF THE INVENTION [0016] The present invention relates to new ring-containing phospholipids of the general formula A-X—PO 3 —W their stereoisomers and geometrical isomers and physiologically acceptable salts thereof, as well as pharmaceutical compositions containing them. [0017] The phospholipid compounds of the present invention of general formula A-X—PO 3 —W in the residue A contain rings of different sizes and types at positions of the phospholipid structure which are not encountered in prior art compounds. The prior art compounds bear only straight or branched alkyl chain substituents in the residue A apart from U.S. Pat. No. 5,436,234 in which there is a tetrahydrofuranyl substituent in residue A. However, the prior art compounds are not covered by the formulae of the compounds claimed in the present invention. [0018] The novel ring-substituted phospholipids of this invention are represented by the general formula A-X—PO 3 —W. [0019] A comprises a radical selected from one of the formulae Y, YR 1 , R 1 Y, R 1 YR 4 , R 1 OY, YOR 1 , R 1 YOR 2 or R 1 OYOR 2 . Advantageously A comprises YR 1 , R 1 YOR 2 or R 1 OYOR 2 [0020] W comprises a radical of the formulae R 3 Q or a C4 to C7 non-aromatic heterocycle containing a nitrogen heteroatom wherein said heterocycle comprising at least one heteroatom independently selected from nitrogen, oxygen, sulfur and combinations thereof, and wherein said heterocycle can be substituted with one or more substituent groups. Advantageously, the substituent groups are independently selected from hydroxyl, halogen, alkyl, cycloalkyl, aryl, alkoxy, alkoxycarbonyl, alkylthio or amino. [0021] Y comprises a carbocyclic ring, a carbocyclic ring comprising at least one substituent group, a fused bicyclic ring system, a fused bicyclic ring system comprising at least one substituent group, a bridged bicyclic ring system, a bridged bicyclic ring system comprising at least one substituent group, a bridged tricyclic ring system, a bridged tricyclic ring system comprising at least one substituent group, a heterocyclic ring, a heterocyclic ring comprising at least one substituent group, an aromatic system or an aromatic system comprising at least one substituent group, a heteroaromatic system or a heteroaromatic system comprising at least one substituent group. [0022] X comprises a valency bond, a methylene group (—CH 2 —) or a heteroatom selected from nitrogen, oxygen, sulfur. Advantageously the heteroatom is an oxygen atom. [0023] R 1 comprises any possible member selected from a carbocyclic ring having about 3 to about 7 ring members, a heterocyclic ring having about 4 to about 7 ring members, an aromatic ring having about 5 to about 7 ring members, a heteroaromatic ring having about 5 to about 7 ring members, or any above group comprising a substituent group on at least one available ring atom, an about C3 to about C20 saturated or unsaturated, straight or branched, aliphatic hydrocarbon chain, an about C3 to about C20 saturated or unsaturated, straight or branched, aliphatic hydrocarbon chain comprising one or more independently chosen heteroatoms, an about C3 to about C20 saturated or unsaturated, straight or branched, aliphatic hydrocarbon chain comprising at least one independently chosen possible member selected from a carbocyclic ring having about 4 to about 7 ring members, a heterocyclic ring having about 4 to about 7 ring members, an aromatic ring having about 5 to about 7 ring members, a heteroaromatic ring having about 5 to about 7 ring members; or any above member comprising a substituent group on at least one available ring atom, or any above about C3 to about C20 hydrocarbon chain having at least one independently chosen substituent group. Advantageously, the substituent groups for the about C3 to about C20 hydrocarbon chain are independently selected from hydroxyl, halogen, alkyl, cycloalkyl, aryl, alkoxy, alkoxycarbonyl, alkythio or amino. [0024] R 2 comprises any possible member selected from a carbocyclic ring having about 3 to about 7 ring members, a heterocyclic ring having about 4 to about 7 ring members, an aromatic ring having about 5 to about 7 ring members, a heteroaromatic ring having about 5 to about 7 ring members; any above group comprising a substituent group on at least one available ring atom, an about C2 to about C5 saturated or unsaturated, straight or branched, aliphatic hydrocarbon chain, an about C2 to about C5 saturated or unsaturated, straight or branched, aliphatic hydrocarbon chain comprising one or more independently chosen heteroatoms, an about C2 to about C5 saturated or unsaturated, straight or branched, aliphatic hydrocarbon chain comprising at least one independently chosen possible member selected from a carbocyclic ring having about 4 to about 7 ring members, a heterocyclic ring having about 4 to about 7 ring members, an aromatic ring having about 5 to about 7 ring members, a heteroaromatic ring having about 5 to about 7 ring members; or any above member comprising a substituent group on at least one available ring atom, or any above about C2 to about C5 hydrocarbon chain having at least one independently chosen substituent group. [0025] Advantageously, R 2 comprises a C2 saturated or unsaturated alkyl or alkenyl, a C2 saturated or unsaturated alkyl or alkenyl which can be substituted with one or more substituents selected from hydroxyl, halogen, alkyl, cycloalkyl, aryl, alkoxy, alkoxycarbonyl, alkylthio and amino. [0026] R 3 comprises any possible member selected from a carbocyclic ring having about 3 to about 9 ring members, a heterocyclic ring having about 4 to about 9 ring members, an aromatic ring having about 5 to about 9 ring members, a heteroaromatic ring having about 5 to about 9 ring members; any above group comprising a substituent group on at least one available ring atom, an about C2 to about C5 saturated or unsaturated, straight or branched, aliphatic hydrocarbon chain, an about C2 to about C5 saturated or unsaturated, straight or branched, aliphatic hydrocarbon chain comprising one or more independently chosen heteroatoms, an about C2 to about C5 saturated or unsaturated, straight or branched, aliphatic hydrocarbon chain comprising at least one independently chosen possible member selected from a carbocyclic ring having about 4 to about 7 ring members, a heterocyclic ring having about 4 to about 7 ring members, an aromatic ring having about 5 to about 7 ring members, a heteroaromatic ring having about 5 to about 7 ring members; or any above member comprising a substituent group on at least one available ring atom, or any above about C2 to about C5 hydrocarbon chain having at least one independently chosen substituent group. [0027] Advantageously R 3 comprises a C2 saturated or unsaturated alkyl or alkenyl, a C2 saturated or unsaturated alkyl or alkenyl which can be substituted with one or more substituents selected from hydroxyl, halogen, alkyl, cycloalkyl, aryl, arylalkyl, alkoxy, alkoxycarbonyl, alkylthio and amino or a C3 to C8 cycloalkyl which is bonded at C1 to the oxygen and at C2 to Q. [0028] R 4 comprises any group independently selected from R 1 or R 2 . [0029] Q comprises an ammonium group, wherein said ammonium group can be substituted one or more times with a C1 to C6 alkyl radical, or comprises a C3 to C7 heterocycle containing a nitrogen heteroatom which is bonded to the R 3 group, wherein said heterocycle can contain one or more heteroatoms independently selected from nitrogen, oxygen, sulfur and combinations thereof, and wherein said heterocycle can be substituted with one or more substituent groups, a heterobicyclic ring containing a nitrogen heteroatom which is bonded to the R 3 group, wherein said heterobicyclic ring can contain one or more heteroatoms independently selected from nitrogen, oxygen, sulfur and combinations thereof, and wherein said heterobicyclic ring can be substituted with one or more substituent groups, a heterotricyclic ring containing a nitrogen heteroatom which is bonded to the R 3 group, wherein said heterotricyclic ring can contain one or more heteroatoms independently selected from nitrogen, oxygen, sulfur and combinations thereof, and wherein said heterotricyclic ring can be substituted with one or more substituent groups. Advantageously the substituent groups are independently selected from hydroxyl, halogen, alkyl, cycloalkyl, aryl, alkoxy, alkoxycarbonyl, alkylthio or amino. [0030] Examples of preferred residue R 1 comprise a C5 to C18 alkylidene group or C5 to C18 alkyl group and most preferred pentylidene, undecylidene, dodecylidene, tetradecylidene, and hexadecylidene group or pentyl, undecyl, dodecyl, tetradecyl and hexadecyl groups. [0031] Examples of preferred Y residue comprise a C3 to C6 carbocyclic ring, a substituted carbocyclic ring, a bridged tricyclic ring system or a substituted bridged tricyclic ring system an aromatic ring and most preferred are cyclohexyl or adamantyl or phenyl. A C2 saturated alkyl is most preferred for R 2 and R 3 . Oxygen is preferred for X. Trimethylammonium, or N-methylmorpholinio or N-methylpiperidinio is most preferred for Q. [0032] The inventive compounds include any and all isomers and steroisomers, as well as their addition salts, particularly their pharmaceutically acceptable addition salts. In general, the compositions of the invention may be alternately formulated to comprise, consist of, or consist essentially of, any appropriate components herein disclosed. The compositions of the invention may additionally, or alternatively, be formulated so as to be devoid, or substantially free, of any components, materials, ingredients, adjuvants or species used in prior art compositions or that are otherwise not necessary to the achievement of the function and/or objectives of the present invention. [0033] Unless otherwise specifically defined, “acyl” refers to the general formula —C(O)alkyl. [0034] Unless otherwise specifically defined, “acyloxy” refers to the general formula —O-acyl. [0035] Unless otherwise specifically defined, “alcohol” refers to the general formula alkyl-OH and includes primary, secondary and tertiary variations. [0036] Unless otherwise specifically defined, “alkyl” or “lower alkyl” refers to a linear, branched or cyclic alkyl group having from 1 to about 16 carbon atoms including, for example, methyl, ethyl, propyl, butyl, hexyl, octyl, isopropyl, isobutyl, tert-butyl, cyclopropyl, cyclohexyl, cyclooctyl, vinyl and allyl. The alkyl group can be saturated or unsaturated. Unless otherwise specifically limited, an alkyl group can be unsubstituted, singly substituted or, if possible, multiply substituted, with substituent groups in any possible position. Unless otherwise specifically limited, a cyclic alkyl group includes monocyclic, bicyclic, tricyclic and polycyclic rings, for example norbornyl, adamantyl and related terpenes. [0037] Unless otherwise specifically defined, “alkoxy” refers to the general formula —O-alkyl. [0038] Unless otherwise specifically defined, “alkylmercapto” refers to the general formula —S-alkyl. [0039] Unless otherwise specifically defined, “alkylamino” refers to the general formula —(NH)-alkyl. [0040] Unless otherwise specifically defined, “di-alkylamino” refers to the general formula —N(alkyl) 2 . Unless otherwise specifically limited di-alkylamino includes cyclic amine compounds such as piperidine and morpholine. [0041] Unless otherwise specifically defined, an aromatic ring is an unsaturated ring structure having about 5 to about 7 ring members and including only carbon as ring atoms. The aromatic ring structure can be unsubstituted, singly substituted or, if possible, multiply substituted, with substituent groups in any possible position. [0042] Unless otherwise specifically defined, “aryl” refers to an aromatic ring system that includes only carbon as ring atoms, for example phenyl, biphenyl or naphthyl. The aryl group can be unsubstituted, singly substituted or, if possible, multiply substituted, with substituent groups in any possible position. [0043] Unless otherwise specifically defined, “aroyl” refers to the general formula —C(═O)-aryl. [0044] Unless otherwise specifically defined, a bicyclic ring structure comprises 2 fused or bridged rings that include only carbon as ring atoms. The bicyclic ring structure can be saturated or unsaturated. The bicyclic ring structure can be unsubstituted, singly substituted or, if possible, multiply substituted, with substituent groups in any possible position. The individual rings may or may not be of the same type. Examples of bicyclic ring structures include, Dimethyl-bicyclo[3,1,1]heptane, bicyclo[2,2,1]heptadiene, decahydro-naphthalene and bicyclooctane. [0045] Unless otherwise specifically defined, a carbocyclic ring is a non-aromatic ring structure, saturated or unsaturated, having about 3 to about 8 ring members that includes only carbon as ring atoms, for example, cyclohexadiene or cyclohexane. The carbocyclic ring can be substituted, singly substituted or, if possible, multiply substituted, with substituent groups in any possible position. [0046] Unless otherwise specifically defined, “halogen” refers to an atom selected from fluorine, chlorine, bromine and iodine. [0047] Unless otherwise specifically defined, a heteroaromatic ring is an unsaturated ring structure having about 5 to about 8 ring members that has carbon atoms and one or more heteroatoms, including oxygen, nitrogen and/or sulfur, as ring atoms, for example, pyridine, furan, quinoline, and their derivatives. The heteroaromatic ring can be unsubstituted, singly substituted or, if possible, multiply substituted, with substituent groups in any possible position. [0048] Unless otherwise specifically defined, a heterobicyclic ring structure comprises 2 fused or bridged rings that include carbon and one or more heteroatoms, including oxygen, nitrogen and/or sulfur, as ring atoms. The heterobicyclic ring structure is saturated or unsaturated. The heterobicyclic ring can be unsubstituted, singly substituted or, if possible, multiply substituted, with substituent groups in any possible position. The individual rings may or may not be of the same type. Examples of heterobicyclic ring structures include tropane, quinuclidine and tetrahydro-benzofuran. [0049] Unless otherwise specifically defined, a heterocyclic ring is a saturated or unsaturated ring structure having about 3 to about 8 ring members that has carbon atoms and one or more heteroatoms, including oxygen, nitrogen and/or sulfur, as ring atoms, for example, piperidine, morpholine, piperazine, pyrrolidine, thiomorpholine, tetrahydropyridine, and their derivatives. The heterocyclic ring can be unsubstituted, singly substituted or, if possible, multiply substituted, with substituent groups in any possible position. [0050] Unless otherwise specifically defined, a heterotricyclic ring structure comprises 3 rings that may be fused, bridged or both fused and bridged, and that include carbon and one or more heteroatoms, including oxygen, nitrogen and/or sulfur, as ring atoms. The heterotricyclic ring structure can be saturated or unsaturated. The heterotricyclic ring structure can be unsubstituted, singly substituted or, if possible, multiply substituted, with substituent groups in any possible position. The individual rings may or may not be of the same type. Examples of heterotricyclic ring structures include 2,4,10-trioxaadamantane, tetradecahydro-phenanthroline. [0051] Unless otherwise specifically defined, a heteropolycyclic ring structure comprises more than 3 rings that may be fused, bridged or both fused and that include carbon and one or more heteroatoms, including oxygen, nitrogen and/or sulfur, as ring atoms. The heteropolycyclic ring structure can be saturated or unsaturated. The heteropolycyclic ring structure can be unsubstituted, singly substituted or, if possible, multiply substituted, with substituent groups in any possible position. The individual rings may or may not be of the same type. Examples of heteropolycyclic ring structures include azaadamantine, 5-norbornene-2,3-dicarboximide. [0052] Unless otherwise specifically defined, the term “phenacyl” refers to the general formula -phenyl-acyl. [0053] Unless otherwise specifically defined, a polycyclic ring structure comprises more than 3 rings that may be fused, bridged or both fused and bridged, and that includes carbon as ring atoms. The polycyclic ring structure can be saturated or unsaturated. The polycyclic ring structure can be unsubstituted, singly substituted or, if possible, multiply substituted, with substituent groups in any possible position. The individual rings may or may not be of the same type. Examples of polycyclic ring structures include adamantine, bicyclooctane, norbornane and bicyclononanes. [0054] Unless otherwise specifically defined, a spirocycle refers to a ring system wherein a single atom is the only common member of two rings. A spirocycle can comprise a saturated carbocyclic ring comprising about 3 to about 8 ring members, a heterocyclic ring comprising about 3 to about 8 ring atoms wherein up to about 3 ring atoms may be N, S, or O or a combination thereof. [0055] Unless otherwise specifically defined, a tricyclic ring structure comprises 3 rings that may be fused, bridged or both fused and bridged, and that includes carbon as ring atoms. The tricyclic ring structure can be saturated or unsaturated. The tricyclic ring structure can be unsubstituted, singly substituted or, if possible, multiply substituted, with substituent groups in any possible position and may be substituted or unsubstituted. The individual rings may or may not be of the same type. Examples of tricyclic ring structures include fluorene and anthracene. [0056] Unless otherwise specifically limited the term substituted means substituted by a below described substituent group in any possible position. Substituent groups for the above moieties useful in the invention are those groups that do not significantly diminish the biological activity of the inventive compound. Substituent groups that do not significantly diminish the biological activity of the inventive compound include, for example, H, halogen, N 3 , NCS, CN, NO 2 , NX 1 X 2 , OX 3 , OAc, O-acyl, O-aroyl, OalkylOH, OalkylNX 1 X 2 , NH-acyl, NH-aroyl, NHCOalkyl, CHO, CF 3 , COOX 3 , SO 3 H, PO 3 X 1 X 2 , OPO 3 X 1 X 2 , SO 2 NX 1 X 2 , CONX 1 X 2 , alkyl, alcohol, alkoxy, alkylmercapto, alkylamino, di-alkylamino, sulfonamide, thioalkoxy, aryl, substituted aryl, heteroaryl, substituted heteroaryl or methylene dioxy when the substituted structure has two adjacent carbon atoms, wherein X 1 and X 2 each independently comprise H or alkyl, or X 1 and X 2 together comprise part of a heterocyclic ring having about 4 to about 7 ring members and optionally one additional heteroatom selected from O, N or S, or X 1 and X 2 together comprise part of an imide ring having about 5 to about 6 members and X 3 comprises H, alkyl, hydroxyloweralkyl, or alkyl-NX 1 X 2 . Unless otherwise specifically limited a substituent group may be in any possible position. [0057] The present invention also pertains to methods for treating protozoal diseases such as leishmaniasis, trypanosomiasis, malaria, toxoplasmosis, babeosis, amoebic dysentery and lambliasis. The method comprises administering an effective infection-combating amount of a compound of the present invention in a therapeutic manner. In one embodiment, an effective dose includes a sufficient amount of one stereoisomer or mixture of stereoisomers where all stereoisomers of said compound possess antiprotozoal properties. In an alternate embodiment, where only one stereoisomer of a compound possesses significant antiprotozoal properties an effective dose comprises a sufficient amount of the pure antiprotozoal stereoisomer. [0058] The compounds of the present invention can be administered topically, enterally and parenterally in liquid or solid form. [0059] The invention further relates to a method of preparing said compounds. According to the invention the compounds of formula A-X—PO 3 —W are synthesized in the following way: [0060] i) Treating the appropriate alcohol A-OH in which A is defined above with phosphorus oxychloride in an organic solvent such as tetrahydrofuran for example in the presence of an organic base, such as triethylamine for example to afford the corresponding phosphoric acid derivative after hydrolysis. [0061] ii) Treating the phosphoric acid said above with 1-(mesitylen-2-sulfonyl)-3-nitro-1H-1,2,4-triazole or 2,4,6-triisopropylbenzenesulfonyl chloride in an organic base, such as pyridine for example followed by the addition of the appropriate alcohol W—OH in which W is defined above and heating the resulting mixture to provide after hydrolysis the phospholipid A-X—PO 3 —W. [0062] The invention will be further illustrated by the following non-limiting examples. EXEMPLIFICATION Synthetic Procedures [0000] General Methods [0063] All reactions were carried out under scrupulously dry conditions. NMR spectra of all new compounds were recorded on a Bruker AC 300 spectrometer operating at 300 MHz for 1 H, 75.43 MHz for 13 C, and 121.44 MHz for 31 P. 1 H NMR spectra are reported in units 6 with CHCl 3 resonance at 7.24 ppm used as the chemical shift resonance. 13 C NMR shifts are expressed in units relative to CDCl 3 at 77.00 ppm, while 31 P NMR spectra are reported in units of δ relative to 85% H 3 PO 4 used as an external standard. Silica gel plates Merck F 254 ) were used for thin-layer chromatography. Chromatographic purification was performed with silica gel (200-400 mesh). [0000] General Procedure for the Preparation of Ether Phospholipids. [0064] To a solution of phosphorus oxychloride (0.09 mL, 1 mmol) and triethylamine (0.25 mL, 1.8 mmol) in dry THF (5 mL) was added dropwise at 0° C. a solution of the corresponding alcohol (1 mmol) in dry THF (7 mL). The resulting mixture was stirred for 2 h at room temperature and subsequently hydrolyzed by the addition of water (3 mL). After 1 h of stirring at room temperature, the reaction mixture was diluted with water and the aqueous layer was extracted with ethyl acetate and dichloromethane. The combined organic extracts were washed with brine, dried with anhydrous Na 2 SO 4 and the solvent was evaporated in vacuo to afford the corresponding phosphoric acid derivative, which was transformed to the pyridinium salt by the addition of 7 mL of anhydrous pyridine and stirring for 2 h at 40° C. After cooling the solvent was evaporated in vacuo and pyridine (5 mL) was added to the residue. To the resulting solution was added dropwise with cooling, a solution of 1-(mesitylen-2-sulfonyl)-3-nitro-1H-1,2,4-triazole (MSNT) (0.593 g, 2 mmol) or 2,4,6-triisopropylbenzenesulfonyl chloride (TIPS-Cl) (0.606 g, 2 mmol) in dry pyridine (2 mL) followed by the addition of choline chloride (0.210 g, 1.5 mmol) or N-(2-hydroxyethyl)-N-methylpiperidinium bromide (0.448 g, 1.5 mmol) or N-(2-hydroxyethyl)-N-methylmorpholinium bromide (0.452 g, 1.5 mmol). The reaction mixture was stirred at 40° C. for 48-56 hours. After cooling, the mixture was hydrolyzed by the addition of H 2 O (2 mL) and 2-propanol (7 mL) and stirred for 1 h at room temperature. The solvents were evaporated in vacuo and the resulting crude solid was purified by gravity column chromatography using initially CH 2 Cl 2 /MeOH/25% NH 4 OH (60/50/5) and subsequently MeOH/25% NH 4 OH (95/5) and the solvents were evaporated in vacuo. The residue was diluted with CHCl 3 and filtered through a pore membrane (0.5 μM, FH Millipore). After evaporation of the solvent the desired product was obtained. Example 1 1-{2-{[(4-Dodecylidenecyclohexyloxy)ethyloxy]hydroxyphosphinyloxy}ethyl}-N,N,N-trimethylammonium inner salt [0065] The general procedure described above using 2-(4-dodecylidenecyclohexyloxy)ethanol, TIPS-Cl and choline chloride afforded the compound named above (0.327 g, 69%). 1 H NMR: δ 5.06 (t, J=6.7 Hz, 1H, C═CH), 4.24 (broad s, 2H, POCH 2 CH 2 N), 3.89 (broad s, 2H), 3.76 (broad s, 2H), 3.57 (broad s, 2H), 3.40-3.35 (m, 1H, CHO), 3.30 (s, 9H, N + (CH 3 ) 3 ), 2.40-1.72 (m, 8H), 1.42-1.33 (m, 2H), 1.24 (broad s, 18H, (CH 2 ) 9 ), 0.84 (t, J=7.0 Hz, 3H, CH 3 ); 31 P NMR: δ −2.16. Example 2 1-{2-{[(4-Dodecylidenecyclohexyloxy)ethyloxy]hydroxyphosphinyloxy}ethyl}-1-methylpiperidinium inner salt [0066] The general procedure described above using 2-(4-dodecylidenecyclohexyloxy)ethanol, TIPS-Cl and N-(2-hydroxyethyl)-N-methylpiperidinium bromide afforded the compound named above (0.350 g, 68%). 1 H NMR δ: 5.16 (t, J=6.70 Hz, 1H, C═CH), 4.24 (bs, 2H, POCH 2 CH 2 N), 3.82-3.55 (m, 10H), 3.30 (broad s, 1H, CHO), 3.25 (s, 3H, N + CH 3 ), 1.92-1.43 (m, 14H), 1.41-1.32 (m, 2H, CH 2 CH═), 1.19 (broad s, 18H, (CH 2 ) 9 ), 0.83 (t, J=7.0 Hz, 3H, CH 3 ); 31 P NMR δ: −2.1. Example 3 1-{2-{[(4-Dodecylidenecyclohexyloxy)ethyloxy]hydroxyphosphinyloxy}ethyl}-1-methylmorpholinium inner salt [0067] The general procedure described above using 2-(4-dodecylidenecyclohexyloxy) ethanol, TIPS-Cl and N-(2-hydroxyethyl)-N-methylmorpholinium bromide afforded the compound named above (0.330 g, 64%). 1 H NMR: δ 5.11 (t, J=6.7 Hz, 1H, C═CH), 4.13 (s, 2H, POCH 2 CH 2 N), 3.82-3.32 (m, 15H), 3.16 (s, 3H, N + CH 3 ), 1.92-1.47 (m, 8H), 1.42-1.34 (m, 2H, CH 2 CH═), 1.27 (broad s, 18H, (CH 2 ) 9 ), 0.83 (t, J=7.0 Hz, 3H, CH 3 ); 31 P NMR δ: −2.04. Example 4 1-{2-{1[(4-Tetradecylidenecyclohexyloxy)ethyloxy]hydroxyphosphinyloxy}ethyl}-N,N,N-trimethylammonium inner salt [0068] The general procedure described above using 2-(4-tetradecylidenecyclohexyloxy)ethanol, TIPS-Cl and choline chloride afforded the compound named above (0.166 g, 33%). 1 H NMR: δ 5.05 (t, J=6.7 Hz, 1H, CH═C), 4.23 (broad s, 2H, POCH 2 CH 2 N), 3.88 (broad s, 2H), 3.75 (broad s, 2H), 3.55 (broad s, 2H, CH 2 N), 3.40-3.35 (m, 1H, CHO), 3.32 (s, 9H, N + (CH 3 ) 3 ), 2.41-2.37 (m, 1H), 2.17-2.13 (m, 1H), 1.89-1.74 (m, 8H), 1.21 (broad s, 22H, (CH 2 ) 11 ), 0.89 (t, J=7.0 Hz, 3H, CH 3 ); 31 P NMR: δ −2.26; 13 C NMR: δ 136.9, 122.7, 74.3, 67.7, 64.7, 54.2, 33.4, 32.5, 31.9, 30.1, 29.6, 29.3, 27.4, 24.9, 22.6, 14.0. Example 5 1-{2-{[(4-Tetradecylidenecyclohexyloxy)ethyloxy]hydroxyphosphinyloxy}ethyl}-1-methylpiperidinium inner salt [0069] The general procedure described above using 2-(4-tetradecylidenecyclohexyloxy) ethanol, TIPS-Cl and N-(2-hydroxyethyl)-N-methylpiperidinium bromide afforded the compound named above (0.201 g, 37%). 1 H NMR: δ 5.21 (t, J=6.7 Hz, 1H, CH═C), 4.31 (bs, 2H, POCH 2 CH 2 N), 3.93-3.80 (m, 4H), 3.60-3.43 (m, 6H, CH 2 N(CH 2 ) 2 ), 3.30 (broad s, 4H, NCH 3 , CHO), 2.40-1.40 (m, 16H), 1.23 (broad s, 22H, (CH 2 ) 11 ), 0.88 (t, J=7.0 Hz, 3H, CH 3 ); 31 P NMR: δ −2.4. Example 6 1-{2-{[(4-Tetradecylidenecyclohexyloxy)ethyloxy]hydroxyphosphinyloxy}ethyl}-1-methylmorpholinium inner salt [0070] The general procedure described above using 2-(4-tetradecylidenecyclohexyloxy) ethanol, TIPS-Cl and N-(2-hydroxyethyl)-N-methylmorpholinium bromide afforded the compound named above (0.218 g, 40%). 1 H NMR: δ 5.06 (t, J=6.7 Hz, 1H, CH═C), 4.07 (broad s, 2H, POCH 2 CH 2 N), 3.49-3.17 (m, 5H), 3.11 (s, 3H, N + CH 3 ), 1.99-1.34 (m, 10H), 1.08 (broad s, 22H, (CH 2 ) 11 ), 0.78 (t, J=7.0 Hz, 3H, CH 3 ); 31 P NMR: δ −1.9. Example 7 1-{2-{[(4-Hexadecylidenecyclohexyloxy)ethyloxy]hydroxyphosphinyloxy}ethyl}-N,N,N-trimethylammonium inner salt [0071] The general procedure described above using 2-(4-hexadecylidenecyclohexyloxy) ethanol, TIPS-Cl and choline chloride afforded the compound named above (0.196 g, 37%). 1 H NMR: δ 5.08 (t, J=6.7 Hz, 1H, CH═C), 4.09 (broad s, 2H, OP(O)CH 2 CH 2 N), 3.82 (broad s, 2H, OCH 2 CH 2 OP), 3.71 (broad s, 2H, OCH 2 CH 2 OP), 3.51-3.43 (m, 2H, CH 2 N), 3.04 (s, 10H, CHO, N + (CH 3 ) 3 ), 2.45-2.40 (m, 1H), 2.25-2.20 (m, 1H), 2.02-1.85 (m, 6H), 1.51-1.42 (m, 2H, CH 2 CH═), 1.09 (broad s, 26H, (CH 2 ) 13 ), 0.71 (t, J=7.0 Hz, 3H, CH 3 ); 31 P NMR: δ −2.04. Example 8 1-{2-{[(4-Hexadecylidenecyclohexyloxy)ethyloxy]hydroxyphosphinyloxy}ethyl}-1-methylpiperidinium inner salt [0072] The general procedure described above using 2-(4-hexadecylidenecyclohexyloxy) ethanol, TIPS-Cl and N-(2-hydroxyethyl)-N-methylpiperidinium bromide afforded the compound named above (0.211 g, 37%). 1 H NMR: δ 5.13 (t, J=6.7 Hz, 1H, CH═C), 4.35 (broad s, 2H, POCH 2 ), 3.87 (broad s, 2H), 3.78 (broad s, 2H), 3.62-3.45 (m, 6H), 3.26 (broad s, 4H), 2.27-1.63 (m, 8H), 1.52-1.41 (m, 2H, CH 2 CH═), 1.24 (broad s, 26H, (CH 2 ) 13 ), 0.89 (t, J=7.0 Hz, 3H, CH 3 ); 31 P NMR: δ −2.0; 13 C NMR: δ 138.0, 117.4, 75.1, 67.8, 67.7, 64.8, 63.3, 61.8, 58.7, 48.8, 37.2, 31.8, 30.1, 29.7, 29.6, 29.4, 29.3, 28.4, 27.7, 27.2, 22.5, 20.9, 20.1, 14.0. Example 9 1-{2-{[(4-Hexadecylidenecyclohexyloxy)ethyloxy]hydroxyphosphinyloxy}ethyl}-1-methylmorpholinium inner salt [0073] The general procedure described above using 2-(4-hexadecylidenecyclohexyloxy) ethanol, TIPS-Cl and N-(2-hydroxyethyl)-N-methylmorpholinium bromide afforded the compound named above (0.206 g, 36%). 1 H NMR: δ 5.06 (t, J=6.70 Hz, 1H, CH═C), 4.41 (bs, 2H, POCH 2 ), 3.99-3.39 (m, 15H), 3.35 (s, 3H, N + CH 3 ), 2.45-2.40 (m, 1H, CHCHOCH 2 ), 2.25-2.20 (m, 1H, CH 2 CHOCH), 2.13-1.85 (m, 6H), 1.22 (broad s, 28H, (CH 2 ) 14 ), 0.89 (t, J=7.0 Hz, 3H, CH 3 ); 31 P NMR: δ −2.17; 13 C NMR: δ 136.8, 122.8, 65.3, 60.7, 33.4, 33.3, 32.4, 31.8, 30.1, 29.6, 29.4, 29.3, 27.4, 24.9, 22.6, 14.0. Example 10 1-{2-[(5-Cyclohexylidenepentyloxy)hydroxyphosphinyloxy]ethyl}-N,N,N-trimethylammonium inner salt [0074] The general procedure described above using 5-cyclohexylidenepentanol, MSNT and choline chloride afforded the compound named above (0.219 g, 66%); 1 H NMR: δ 4.99 (t, J=6.7 Hz, 1H, C═CH), 4.21 (broad s, 2H, POCH 2 CH 2 N), 3.74 (broad s, 4H, CH 2 OPOCH 2 CH 2 N), 3.34 (s, 9H, N + (CH 3 ) 3 ), 2.09-1.84 (m, 6H), 1.55-1.28 (m, 10H); 31 P NMR: δ −2.16; 13 C NMR: δ 139.8, 120.8, 66.1, 65.4, 59.1, 54.2, 37.1, 30.6, 28.6, 27.8, 26.9, 26.4, 25.6; ESI-MS m/z: 356.2 (M + +Na + ), 334.2 (M + ). Example 11 1-{2-[(5-Cyclohexyldenepentyloxy)hydroxyphosphinyloxy]ethyl}-1-methylpiperidinium inner salt [0075] The general procedure described above using 5-cyclohexylidenepentanol, MSNT and N-(2-hydroxyethyl)-N-methylpiperidinium bromide afforded the compound named above (0.153 g, 41%); 1 H NMR: δ 5.02 (t, J=6.7 Hz, 1H, C═CH), 4.28 (broad s, 2H, POCH 2 CH 2 N), 3.82-3.42 (m, 8×, CH 2 OPOCH 2 CH 2 N(CH 2 ) 2 ), 3.31 (s, 3H, N + CH 3 ), 2.08-1.48 (m, 16H), 1.23 (broad s, 6H, (CH 2 ) 3 ); 31 P NMR: δ −2.04; ESI-MS m/z: 374.2 (M + ). Example 12 1-{2-[(5-Cyclohexylidenepentyloxy)hydroxyphosphinyloxy]ethyl}-1-methylmorpholinium inner salt [0076] The general procedure described above using 5-cyclohexylidenepentanol, MSNT and N-(2-hydroxyethyl)-N-methylmorpholinium bromide afforded the compound named above (0.153 g, 41%). 1 H NMR: δ 5.01 (t, J=6.7 Hz, 1H, C═CH), 4.29 (broad s, 2H, POCH 2 CH 2 N), 4.11-3.68 (m, 12H), 3.42 (s, 3H, N + CH 3 ), 2.09-1.95 (m, 4H), 1.58-1.49 (m, 6H), 1.31 (broad s, 6H, (CH 2 ) 3 ); 31 P NMR: δ −2.23; ESI-MS m/z: 376.2 (M + ). Example 13 1-{2-[(11-Cyclohexylideneundecyloxy)hydroxyphosphinyloxy]ethyl}-N,N,N-trimethylammonium inner salt [0077] The general procedure described above using 11-cyclohexylideneundecanol, MSNT and choline chloride afforded the compound named above (0.220 g, 52%). 1 H NMR δ: 5.05 (t, J=6.7 Hz, 1H, C═CH), 4.20 (broad s, 2H, POCH 2 CH 2 N), 3.75-3.68 (m, 4H, CH 2 OPOCH 2 CH 2 N), 3.26 (s, 9H, N + (CH 3 ) 3 ), 2.11-1.92 (m, 4H), 1.65-1.48 (1,6H), 1.23 (broad s, 18H, (CH 2 ) 9 ); 31 P NMR: δ −2.45; 13 C NMR: δ 131.0, 124.8, 66.1, 66.0, 59.1, 54.1, 31.0, 30.2, 29.9, 29.7, 29.6, 29.5, 29.3, 28.6, 28.0, 27.8, 27.0, 26.9, 25.9, 25.7; ESI-MS m/z: 440.2 (M + +Na + ), 418.2 (M + ). Example 14 1-{2-[(11-Cyclohexylideneundecyloxy)hydroxyphosphinyloxy]ethyl}-1-methylpiperidinium inner salt [0078] The general procedure described above using 11-cyclohexylideneundecanol, MSNT and N-(2-hydroxyethyl)-N-methylpiperidinium bromide afforded the compound named above (0.315 g, 69%). 1 H NMR: δ 4.99 (t, J=6.7 Hz, 1H, C═CH), 4.23 (bs, 2H, POCH 2 CH 2 N), 3.78-3.48 (m, 8H, CH 2 OPOCH 2 CH 2 N(CH 2 ) 2 ), 3.27 (s, 3H, N + CH 3 ), 2.04-1.45 (m, 16H), 1.18 (broad s, 18H, (CH 2 ) 9 ); 31 P NMR δ: −2.04; 13 C NMR: δ 130.9, 124.7, 65.3, 63.2, 58.4, 48.5, 37.0, 31.0, 30.9, 30.1, 29.8, 29.6, 29.5, 29.4, 29.2, 28.6, 27.9, 27.7, 26.8, 25.8, 25.6; ESI-MS m/z: 480.3 (M + +Na + ), 458.3 (M + ). Example 15 1-{2-[(11-Cyclohexylideneundecyloxy)hydroxyphosphinyloxy]ethyl}-1-methylmorpholinium inner salt [0079] The general procedure described above using 11-cyclohexylideneundecanol, MSNT and N-(2-hydroxyethyl)-N-methylmorpholinium bromide afforded the compound named above (0.117 g, 25%). 1 H NMR: δ 5.05 (t, J=6.7 Hz, 1H, C═CH), 4.29 (broad s, 2H, POCH 2 CH 2 N), 3.99-3.70 (m, 12H), 3.48 (s, 3H, N + CH 3 ), 2.08-1.92 (m, 4H), 1.65-1.48 (m, 6H), 1.23 (s, 18H, (CH 2 ) 9 ); 31 P NMR: 6-2.13; 13 C NMR: δ 131.0, 124.8, 65.8, 64.3, 60.7, 58.5, 48.3, 37.1, 31.0, 30.9, 29.9, 29.7, 29.6, 29.5, 29.4, 29.3, 28.6, 28.2, 28.0, 27.8, 27.0, 25.8, 25.7, 17.6. Example 16 1-{2-[(5-Adamantylidenepentyloxy)hydroxyphosphinyloxy]ethyl}-N,N,N-trimethylammonium inner salt [0080] The general procedure described above using 5-adamantylidenepentanol, MSNT and choline chloride afforded the compound named above (0.223 g, 58%). 1 H NMR: δ 4.96 (t, J=6.7 Hz, 1H, C═CH), 4.22 (broad s, 2H, POCH 2 CH 2 N), 3.77-3.71 (m, 4H, CH 2 OPOCH 2 CH 2 N), 3.29 (s, 9H, N + (CH 3 ) 3 ), 2.75 (s, 1H, CHC═), 2.27 (s, 1H, CHC═), 1.95-1.53 (m, 161), 1.34-1.29 (m, 2H); 31 P NMR: δ −2.42; 13 C NMR: δ 147.7, 115.9, 66.3, 65.5, 59.1, 54.3, 40.5, 39.8, 38.9, 37.2, 32.0, 30.6, 28.6, 26.6, 26.2; ESI-MS m/z: 408.1 (M + +Na + ), 386.1 (M + ). Example 17 1-(2-[(5-Adamantlidenepentloxy)hydroxyphosphinyloxy]ethyl)-1-methylpiperidinium inner salt [0081] The general procedure described above using 5-adamantylidenepentanol, MSNT and N-(2-hydroxyethyl)-N-methylpiperidinium bromide afforded the compound named above (0.272 g, 64%). 1 H NMR δ: 4.93 (t, J=6.7 Hz, 1H, C═CH), 4.25 (broad s, 2H, POCH 2 CH 2 N), 3.79-3.60 (m, 8H, CH 2 OPOCH 2 CH 2 N(CH 2 ) 2 ), 3.32 (s, 3H, N + (CH 3 ) 3 ), 2.72 (s, 1H, CHC═), 2.24 (s, 1H, CHC═), 1.92-1.50 (m, 22H), 1.31-1.26 (m, 2H); 31 P NMR: δ −1.9; 13 C NMR: δ 147.6, 115.9, 65.4, 65.3, 63.5, 58.6, 58.5, 48.6, 40.5, 39.8, 38.9, 37.2, 32.0, 30.7, 30.6, 28.6, 26.6, 26.2, 20.9, 20.2; ESI-MS m/z: 448.2 (M + +Na + ), 426.2 (M + ). Example 18 1-{2-[(5-Adamantylidenepentyloxy)hydroxyphosphinyloxy]ethyl}-1-methylmorpholinium inner salt [0082] The general procedure described above using 5-adamantylidenepentanol, MSNT and N-(2-hydroxyethyl)-N-methylmorpholinium bromide afforded the compound named above (0.239 g, 56%). 1 H NMR δ: 4.94 (t, J=6.7 Hz, 1H, C═CH), 4.27 (broad s, 2H, POCH 2 CH 2 N), 3.99-3.69 (m, 12H), 3.43 (s, 3H, N + CH 3 ), 2.73 (s, 1H, CHC═), 2.25 (s, 1H, CHC═), 1.96-1.32 (m, 16H), 1.29-1.18 (m, 2H); 31 P NMR: δ −2.16; 13 C NMR: δ 147.8, 115.8, 65.6, 65.5, 64.3, 60.7, 58.5, 48.3, 40.5, 39.8, 38.9, 37.2, 32.0, 30.6, 30.5, 28.6, 26.6, 26.5; ESI-MS m/z: 450.2 (M + +Na + ), 428.2 (M + ). Example 19 1-{2-[(11-Adamantylideneundecyloxy)hydroxyphosphinyloxy]ethyl}-N,N,N-trimethylammonium inner salt [0083] The general procedure described above using 11-adamantylideneundecanol, MSNT and choline chloride afforded the compound named above (0.248 g, 53%). 1 H NMR: δ 4.98 (t, J=6.7 Hz, 1H, C═CH), 4.21 (broad s, 2H, POCH 2 CH 2 N), 3.75 (broad s, 4H, CH 2 OPOCH 2 CH 2 N), 3.32 (s, 9H, N + (CH 3 ) 3 ), 2.77 (s, 1H, CHC═), 2.28 (s, 1H, CHC═), 1.91-1.53 (m, 16H), 1.23 (broad s, 14H); 31 P NMR: δ −2.16; 13 C NMR: δ: 147.2, 116.3, 66.1, 65.5, 59.2, 54.2, 40.5, 39.8, 38.9, 37.3, 32.0, 31.0, 30.9, 29.7, 29.6, 29.5, 29.2, 28.7, 26.5, 25.9; ESI-MS m/z: 492.2 (M + +Na + ), 470.2 (M + ). Example 20 1-{2-[(11-Adamantylideneundecyloxy)hydroxyphosphinyloxy]ethyl}-1-methylpiperidinium inner salt [0084] The general procedure described above using 11-adamantylideneundecanol, MSNT and N-(2-hydroxyethyl)-N-methylpiperidinium bromide afforded the compound named above (0.168 g, 33%). 1 H NMR δ: 4.98 (t, J=6.7 Hz, 1H, C═CH), 4.27 (broad s, 2H, POCH 2 CH 2 N), 3.84-3.52 (m, 8H, CH 2 OPOCH 2 CH 2 N(CH 2 ) 2 ), 3.32 (s, 3H, NCH 3 ), 2.76 (s, 1H, CHC═), 2.27 (s, 1H, CHC═), 1.92-1.53 (m, 22H), 1.23 (broad s, 14H); 31 P NMR: δ−2.04; 13 C NMR: δ 147.2, 116.3, 65.1, 62.1, 57.3, 47.4, 40.5, 39.9, 38.9, 37.5, 32.0, 30.3, 29.6, 29.5, 29.4, 29.2, 28.7, 26.4, 25.8, 20.9, 20.2; ESI-MS m/z: 532.3 (M + +Na + ), 510.3 (M + ). Example 21 1-{2-[(11-Adamantylideneundecyloxy)hydroxyphosphinyloxy]ethyl}-1-methylmorpholinium inner salt [0085] The general procedure described above using 11-adamantylideneundecanol, MSNT and N-(2-hydroxyethyl)-N-methylmorpholinium bromide afforded the compound named above (0.235 mg, 46%). 1 H NMR: δ 4.99 (t, J=6.7 Hz, 1H, C═CH), 4.29 (broad s, 2H, POCH 2 CH 2 N), 4.00-3.67 (m, 12H), 3.42 (s, 3H, N + CH 3 ), 2.77 (s, 1H, CHC═), 2.28 (s, 1H, CHC═), 1.91-1.54 (m, 14H), 1.23 (s, 16H); 31 P NMR: δ −2.29; 13 C NMR: δ 147.2, 116.3, 65.7, 64.9, 60.7, 58.5, 48.3, 40.5, 39.8, 38.9, 37.3, 32.0, 30.9, 30.4, 29.7, 29.6, 29.5, 29.3, 28.6, 26.5, 25.8; ESI-MS m/z: 534.2 (M + +Na + ), 512.2(M + ). Example 22 1-{2-{[(4-(Dodecyloxy)cyclohexyloxy)ethyloxy]hydroxyphosphinyloxy}ethyl}-1-methylpiperidinium inner salt [0086] The general procedure described above using 2-[4-(dodecyloxy)cyclohexyloxy]ethanol, TIPS-Cl and N-(2-hydroxyethyl)-N-methylpiperidinium bromide afforded the compound named above (0.241 g, 45%). 1 H NMR: δ 4.26 (bs, 2H), 3.88-3.79 (m, 4H), 3.58-3.38 (m, 6H), 3.36-3.27 (m, 7H), 1.95-1.40 (m, 34H), 0.83 (t, J=7.0 Hz, 3H); 31 P NMR: δ −2.26. Example 23 1-{2-{[(4-(Dodecyloxy)cyclohexyloxy)ethyloxy]hydroxyphosphinyloxy}ethyl}-1-methylmorpholinium inner salt [0087] The general procedure described above using 2-[4-(dodecyloxy)cyclohexyloxy]ethanol, TIPS-Cl and N-(2-hydroxyethyl)-N-methylmorpholinium bromide afforded the compound named above (0.213 g, 40%). 1 H NMR: δ 4.32 (broad s, 2H), 4.04-3.19 (m, 21H), 1.99-1.50 (m, 28H), 0.86 (t, J=7.0 Hz, 3H, CH 3 ); 31 P NMR: δ −2.5. Example 24 1-{2-{[(4-(Tetradecyloxy)cyclohexyloxy)ethyloxy]hydroxyphosphinyloxy}ethyl}-1-methylpiperidinium inner salt [0088] The general procedure described above using 2-[4-(tetradecyloxy)cyclohexyloxy]ethanol, TIPS-Cl and choline chloride afforded the compound named above (0.214 g, 38%). [0089] 1 H NMR: δ 4.31 (bs, 2H), 3.93-3.84 (m, 4H), 3.62-3.54 (m, 6H), 3.36-3.27 (m, 7H), 1.87-1.20 (m, 38H), 0.83 (t, J=7.0 Hz, 3H); 31 P NMR: δ −2.32. Example 25 1-{2-{[(4-(Tetradecyloxy)cyclohexyloxy)ethyloxy]hydroxyphosphinyloxy}ethyl}-1-methylmorpholinium inner salt [0090] The general procedure described above using 2-[4-(tetradecyloxy)cyclohexyloxy]ethanol, TIPS-Cl and N-(2-hydroxyethyl)-N-methylmorpholinium bromide afforded the compound named above (0.236 g, 42%). 1 H NMR: δ 4.32 (broad s, 2H), 3.96-3.19 (m, 21H), 1.89-1.50 (m, 32H), 0.86 (t, J=7.0 Hz, 31); 31 P NMR: δ −2.11. [0000] General Procedure for the Hydrogenation of the Unsaturated Ether Phospholipids [0091] To a solution of the desired ether phospholipid (1 mmol) in MEOH (10 mL) was added 10% Pd/C (10% w/w) and the resulting mixture was hydrogenated at 1 Atm for 10 h. Filtration through celite and evaporation of the filtrate in vacuo afforded the pure product. Example 26 1-{2-{[(4-Dodecylcyclohexyloxy)ethyloxy]hydroxyphosphinyloxy}ethyl}-N,N,N-trimethylammonium inner salt [0092] The general procedure described above using the compound of Example 1 afforded the compound named above (yield quantitative). 1 H NMR: δ: 4.31 (broad s, 2H, POCH 2 CH 2 N), 3.93 (broad s, 2H, CH 2 OPOCH 2 CH 2 N), 3.82 (broad s, 2H), 3.59 (broad s, 2H, POCH 2 CH 2 N), 3.37 (broad s, 10H, CHO, N + (CH 3 ) 3 ), 2.05-1.95 (m, 1H), 1.76-1.72 (m, 2H), 1.46-1.10 (m, 28H), 0.86 (t, J=7.0 Hz, 3H, CH 3 ). Example 27 1-{2-{[(4-Tetradecylcyclohexyloxy)ethyloxy]hydroxyphosphinyloxy}ethyl}-N,N,N-trimethylammonium inner salt [0093] The general procedure described above using the compound of Example 4 afforded the compound named above (yield quantitative). 1 H NMR: δ 4.31 (broad s, 2H, POCH 2 CH 2 N), 3.93-3.82 (m, 4H), 3.59-3.15 (m, 12H), 1.96 (broad s, 1H), 1.76 (broad s, 2H), 1.42-1.09 (m, 32H), 0.87 (t, J=7.0 Hz, 3H, CH 3 ). Example 28 1-{2-[(11-Cyclohexylundecyloxy)hydroxyphosphinyloxy]ethyl}-N,N,N-trimethylammonium inner salt [0094] The general procedure described above using the compound of Example 13 afforded the compound named above (yield quantitative). 1 H NMR: δ 4.20 (broad s, 2H, POCH 2 CH 2 N), 3.75-3.68 (m, 4H, CH 2 OPOCH 2 CH 2 N), 3.26 (s, 9H, N + (CH 3 ) 3 ), 2.09-1.12 (m, 13H), 1.23 (s, 18H, (CH 2 ) 9 ). Example 29 1-{2-[(5-Adamantylpentyloxy)hydroxyphosphinyloxy]ethyl}-N,N,N-trimethylammonium inner salt [0095] The general procedure described above using the compound of Example 16 afforded the compound named above (yield quantitative). 1 H NMR: a 4.27 (bs, 2H, POCH 2 CH 2 N), 3.79-3.09 (m, 13H), 2.02-1.25 (m, 23H). Example 30 1-{2-[(11-Adamantylundecyloxy)hydroxyphosphinyloxy]ethyl-N,N,N-trimethylammonium inner salt [0096] The general procedure described above using the compound of Example 19 afforded the compound named above (yield quantitative). 1 H NMR: δ 4.27 (broad s, 2H, POCH 2 CH 2 N), 3.79-3.09 (m, 13H), 2.02-1.25 (m, 35H). [0000] Determination of in Vitro Antileishmanial Activity in Promastigote Cultures. [0097] The effect of the phospholipids according to the present invention against the promastigote forms of Leishmania donovani and Leishmania infantum was evaluated using an MTT (3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide)-based enzymatic method as a marker of cell viability and was compared with that of the ether phospholipid hexadecylphosphocholine (Miltefosine). Thus, promastigotes of Leishmania infantum MHOM/ITN/80/IPT1/LEM 235 and Leishmania donovani MHOM/TN/80/DD8/LEM 703, were grown in RPMI 1640 supplemented with 10% FCS, L. glutamine and antibiotics, at 26° C. All new compounds were dissolved in DMSO to a final concentration of 9.625 mM and linear 3-fold dilutions were done in the culture medium. 25 μL of promastigote culture at 5×10 5 cells/mL were cultured in a 96-well flat-bottom plate (Costar 3696), and incubated with 25 μL of different drug concentrations at 26° C. After 72 h, 10 μL of 5 mg/nL MTT in PBS (SIGMA M2128) were added and incubation was continued for 3 h. The reaction was stopped by the addition of 50 μL of 50% isopropanol, 10% SDS under gentle shacking for 30 min. Absorbance was measured at 550 nm with reference at 620 nm in a TRITURUS microplate reader. TABLE 1 In vitro antileishmanial activity* against the promastigote forms of L. infantum and L. donovani of phospholipids of the present invention. IC 50 (μM) IC 50 (μM) L. infantum L. donovani Compound MON 235 MON 703 Miltefosine 22.56 ± 3.6  23.71 ± 4.07  1-{2-{[(4-Dodecylidenecyclohexyloxy)ethyloxy]hydroxy-  3.25 ± 0.65 7.08 ± 1.2  phosphinyloxy}ethyl}-N,N,N-trimethylammonium inner salt. 1-{2-{[(4-Dodecylidenecyclohexyloxy)ethyloxy]hydroxy- 23.07 ± 3.6    22 ± 3.25 phosphinyloxy}ethyl}-1-methylpiperidinium inner salt. 1-{2-{[(4-Dodecylidenecyclohexyloxy)ethyloxy]hydroxy- 16.46 ± 1.8  50.67 ± 3.6  phosphinyloxy}ethyl}-1-methylmorpholinium inner salt. 1-{2-{[(4-Tetradecylidenecyclohexyloxy)ethyloxy]hydroxy-  5.25 ± 0.45 3.91 ± 0.21 phosphinyloxy}ethyl}-N,N,N-trimethylammonium inner salt. 1-{2-{[(4-Tetradecylidenecyclohexyloxy)ethyloxy]hydroxy- 11.4 ± 2.4 29.7 ± 3.6  phosphinyloxy)ethyl}-1-methylpiperidinium inner salt. 1-{2-{[(4-Tetradecylidenecyclohexyloxy)ethyloxy]hydroxy- 15.5 ± 1.8 38.6 ± 3.2  phosphinyloxy)ethyl}-1-methylmorpholinium inner salt. 1-{2-{[(4-Hexadecylidenecyclohexyloxy)ethyloxy]hydroxyl- 21.19 ± 2.6  45.1 ± 7.2  phosphinyloxy)ethyl}-N,N,N-trimethylammonium inner salt. 1-{2-{[(4-Hexadecylidenecyclohexyloxy)ethyloxy]hydroxy-  6.5 ± 1.7 21.96 ± 1.99  phosphinyloxy}ethyl}-1-methylpiperidinium inner salt. 1-{2-{[(4-Hexadecylidenecyclohexyloxy)ethyloxy]hydroxy-  3.7 ± 0.71 16.22 ± 2.29  phosphinyloxy}ethyl}-1-methylmorpholinium inner salt. 1-{2-[(5-Cyclohexylidenepentyloxy)hydroxyphosphinyloxy]ethyl}-N,N,N- >100 >100 trimethylammonium inner salt. 1-{2-[(5-Cyclohexylidenepentyloxy)hydroxyphosphinyloxy]ethyl}-1- >100 >100 methylpiperidinium inner salt. 1-{2-[(5-Cyclohexylidenepentyloxy)hydroxyphosphinyloxy]ethyl}-1- >100 >100 methylmorpholinium inner salt. 1-{2-[(11-Cyclohexylideneundecyloxy)hydroxy-  5.2 ± 1.5 2.4 ± 0.6 phosphinyloxy]ethyl}-N,N,N-trimethylammonium inner salt. 1-{2-[(11-Cyclohexylideneundecyloxy)hydroxy-  47.6 ± 7.33 8.7 ± 1   phosphinyloxy]ethyl}-1-methylpiperidinium inner salt. 1-{2-[(11-Cyclohexylideneundecyloxy)hydroxy- 22.8 ± 1.7 8.25 ± 0.25 phosphinyloxy]ethyl}-1-methylmorpholinium inner salt. 1-{2-[(5-Adamantylidenepentyloxy)hydroxy- >100 4.99 ± 1.50 phosphinyloxy]ethyl}-N,N,N-trimethylammonium inner salt. 1-{2-[(5-Adamantylidenepentyloxy)hydroxy- >100 >100 phosphinyloxy]ethyl}-1-methylpiperidinium inner salt. 1-{2-[(5-Adamantylidenepentyloxy)hydroxy- >100 46.85 ± 8.7  phosphinyloxy]ethyl}-1-methylmorpholinium inner salt. 1-{2-[(11-Adamantylideneundecyloxy)hydroxy- 6.75 ± 2.4 3.16 ± 0.63 phosphinyloxy]ethyl}-N,N,N-trimethylammonium inner salt. 1-{2-[(11-Adamantylideneundecyloxy)hydroxy- 22.58 ± 3.4  5.41 ± 1.14 phosphinyloxy]ethyl}-1-methylpiperidinium inner salt. 1-{2-[(11-Adamantylideneundecyloxy)hydroxy- 6.64 ± 1.2 5.09 ± 1.86 phosphinyloxy]ethyl}-1-methylmorpholinium inner salt. 1-{2-{[(4-Dodecylcyclohexyloxy)ethyloxy]hydroxy-  5.65 ± 1.93 9.49 ± 1.4  phosphinyloxy}ethyl-N,N,N-trimethylammonium inner salt. 1-{2-{[(4-Tetradecylcyclohexyloxy)ethyloxy]hydroxy- 23.3 ± 3.5 23.65 ± 4.4  phosphinyloxy}ethyl}-N,N,N-trimethylammonium inner salt. 1-{2-[(11-Cyclohexylundecyloxy)hydroxyphosphinyloxy]  8.4 ± 0.8 10.3 ± 1.3  ethyl}-N,N,N-trimethylammonium inner salt. 1-{2-[(5-Adamantylpentyloxy)hydroxyphosphinyloxy]ethyl}- >100 4.02 ± 2.3  N,N,N-trimethylammonium inner salt. 1-{2-[(11-Adamantylundecyloxy)hydroxyphosphinyloxy]  5.97 ± 1.06 2.88 ± 0.72 ethyl}-N,N,N-trimethylammonium inner salt. *Results are expressed as mean ± SEM, n = 3-4 (each run in duplicate). [0098] It is worth noting that the length of the alkyl chain of active compounds of the present invention varies from 5 to 11 carbon atoms for the alkylphosphocholine analogues and from 12 to 14 for the alkoxyethylphosphocholine analogues. This could be advantageous for the solubility and/or the toxicity of the new compounds and also for their metabolic clearance. Thus, we proceeded to assess the cytotoxicity of four inventive compounds as well as miltefosine in the human monocytic cell line THP1. [0099] Assessment of Catotoxicity in THP1 Monocyte Cells. [0100] As a quantitative measurement of the cell damage after incubation with different concentrations of drugs dual staining with SYBR-14 and PI (Molecular Probes, The Netherlands) was used followed by flow cytometry. [0000] Staining with PI and SYBR-14 [0101] THP1 cell cultures were incubated at 1×10 6 cells/ml with different concentrations of the compounds ranging from 50 to 1.56. After an incubation period of 72 hours approximately 4×10 6 cells were suspended in labeling buffer (10 mM HEPES, 150 mM NaCl, 10% BSA, pH 7.4) and 10 μg/ml PI and 0.1 mg/ml SYBR-14 were added. The cultures were incubated at 37° C. for 30 minutes before analysis by flow cytometry. [0000] Flow Cytometry Analysis. [0102] Cell samples were analyzed on an Epics Elite model flow cytometer (Coulter, Miami, Fla.). The green fluorescence of SYBR-14 and the red fluorescence of PI were excited at 488 nm. At least 10,000 cells were analyzed per sample and each staining experiment was repeated twice. Data analysis was performed on fluorescence intensities that excluded cell autofluorescence and cell debris. [0103] THP1 monocytes infected with the appropriate Leishmania species were used for the evaluation of the leishmanicidal activity of the compounds against the intracellular amastigote stages of the parasite. As shown in FIG. 1 , the evaluation of cytotoxic activity on infected THP1 monocytes with L. dontovani and L. infantum showed a very strong cytotoxic effect of miltefosine on THP1 cells at concentrations as low as 50 μM, which was not observed with two of the most active analogues (compounds 13 and 19) of the present invention.

Disclosed are novel ring containing phospholipids represented by the structural formula A-X—PO 3 —W and physiologically acceptable salts thereof and a process for the preparation of these compounds. The compounds can be used for the treatment of protozoal diseases and especially leishmaniasis.

BACKGROUND Building highly effective customer service applications, in an interactive voice response (IVR) system, is complex and expensive. The value of these investments is reduced when users fail to negotiate the IVR prompts correctly, ultimately having their transaction needs met by a call center agent. When the customer is served by an agent three things occur. First, the customer is not taught how to overcome the error generated in the IVR, so they are prone to invoke the more costly agent processing of their request in a subsequent transaction. Second, the customer's preference for agent supported transactions is rewarded, hence discouraging continued use of the IVR. And third, the agent serving the IVR can be occupied with completing all of the transactions needed by the customer on that interaction with the enterprise, thus, increasing operational expenses for the center. Currently, when users experience problems using an IVR there are three solutions. First, the most commonly applied solution is to have the call transferred to an agent, and the agent handles all the transactions associated with that call for the customer. In this model, the IVR is abandoned for the transaction where the customer is forced out or presses zero (0) to exit the IVR. Second and less frequently, an agent takes the customer's call following the failed use of the IVR and completes the transaction with which the customer struggled. If the customer has multiple transactions to complete in that call, the agent generally transfers the customer back into the IVR to complete the subsequent transactions. Finally, the least frequent occurring solution is categorized as “Agent Assisted IVR.” In this method, dedicated call center agents are concurrently listening to multiple customer interactions within the IVRs. The customer is not aware that their interaction within the IVR is being monitored. When the customer experiences a problem, the agent tries to intervene by advancing the IVR script on the caller's behalf. This method has limited application. This method provides some opportunity to improve customer IVR usage. For example, the agent responds for a customer with a heavy accent that cannot be recognized by the IVR's speech engine. The heavy accent is, however, discernible by the monitoring agent, and the agent can “push” the call along to the appropriate next menu step, without interacting with the customer. However, this type of agent assistance is limited in its application. For example, if the customer cannot input their account number, the monitoring agent cannot correct the account number. Typical solutions today do nothing to encourage or train the customer on how to use the IVR. These present methods do not change the likelihood that a customer will engage a more expensive call center agent when exiting IVR functions. The current solutions create five problems: (1) restarting interactions after the customer abandoned their progress in the IVR; (2) impeding the uptake of the IVR for service delivery (the customer continues to prefer to use a human agent); (3) preventing the customer from learning the IVR system; dissuading organizations from placing more complicated applications on the IVR system because complicated functions have higher user error rates; and (5) propagating the perception that IVR systems are poor service delivery mechanisms. SUMMARY It is with respect to the above issues and other problems that the embodiments presented herein were contemplated. A system is provided to conference a customer with the agent and the IVR system. The system can automatically monitor the customer's interaction with the IVR system. If needed, the system can automatically identify that the customer is having difficulties with the IVR script executed by the IVR system. In response, the system can then engage an agent, the IVR system, and the customer in a conference. The agent can direct responses to the IVR script. Rather than completing the interactions for the customer, the agent can instruct the customer on how to answer or interact with the IVR system. The solution engages a live agent in a multi-party call type arrangement with the user and the IVR when the user makes an error in the IVR. The agent is provided with information about the IVR process being executed and the user's input. When the agent is introduced into the call, the agent does not take over the transaction, rather, the agent helps direct the user to provide the correct input to the IVR prompt. Once the issue is corrected, the agent can remove themselves from the customer/IVR dialogue. As a consequence: the user continues their self-service transactions in the IVR, and the user is better educated on how to navigate the IVR in the future. Further, agent resources are spared from supporting subsequent transactions within the same interaction with the user, and the user is less likely to have a negative opinion of the IVR so subsequent reuse is more probable. The system and method has several advantages. The user is not diverted away from the IVR to be served by a call center agent. Rather, the agent is brought into the IVR dialogue for a very limited period of time to assist the user with the IVR dialogue. After the service is delivered, the agent is released and the user remains engaged with the IVR to complete the transaction. Progressively, customers will learn how to avoid IVR interaction errors and become more self-sufficient—reducing the resources needed to help customer complete IVR supported transactions. The phrases “at least one”, “one or more”, and “and/or” are open-ended expressions that are both conjunctive and disjunctive in operation. For example, each of the expressions “at least one of A, B and C”, “at least one of A, B, or C”, “one or more of A, B, and C”, “one or more of A, B, or C” and “A, B, and/or C” means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B and C together. The term “a” or “an” entity refers to one or more of that entity. As such, the terms “a” (or “an”), “one or more” and “at least one” can be used interchangeably herein. It is also to be noted that the terms “comprising”, “including”, and “having” can be used interchangeably. The term “automatic” and variations thereof, as used herein, refers to any process or operation done without material human input when the process or operation is performed. However, a process or operation can be automatic, even though performance of the process or operation uses material or immaterial human input, if the input is received before performance of the process or operation. Human input is deemed to be material if such input influences how the process or operation will be performed. Human input that consents to the performance of the process or operation is not deemed to be “material”. The term “computer-readable medium” as used herein refers to any tangible storage that participates in providing instructions to a processor for execution. Such a medium may take many forms, including but not limited to, non-volatile media, volatile media, and transmission media. Non-volatile media includes, for example, NVRAM, or magnetic or optical disks. Volatile media includes dynamic memory, such as main memory. Common forms of computer-readable media include, for example, a floppy disk, a flexible disk, hard disk, magnetic tape, or any other magnetic medium, magneto-optical medium, a CD-ROM, any other optical medium, punch cards, paper tape, any other physical medium with patterns of holes, a RAM, a PROM, and EPROM, a FLASH-EPROM, a solid state medium like a memory card, any other memory chip or cartridge, or any other medium from which a computer can read. When the computer-readable media is configured as a database, it is to be understood that the database may be any type of database, such as relational, hierarchical, object-oriented, and/or the like. Accordingly, the embodiments are considered to include a tangible storage medium and prior art-recognized equivalents and successor media, in which the software implementations are stored. The terms “determine”, “calculate” and “compute,” and variations thereof, as used herein, are used interchangeably and include any type of methodology, process, mathematical operation or technique. The term “module” as used herein refers to any known or later developed hardware, software, firmware, artificial intelligence, fuzzy logic, or combination of hardware and software that is capable of performing the functionality associated with that element. While exemplary embodiments are described, it should be appreciated that individual aspects can be separately claimed. BRIEF DESCRIPTION OF THE DRAWINGS The present disclosure is described in conjunction with the appended figures: FIG. 1 is a block diagram of an embodiment of a contact center; FIG. 2 is a block diagram of an embodiment of a contact center server; FIG. 3 is another block diagram of an embodiment of a contact center server including a caller evaluation system; FIG. 4 is a block diagram of an embodiment of a data structure for evaluating a caller for hiring into the contact center; FIG. 5 is a flow diagram of an embodiment of a process for rating a caller and storing a personal profile of the caller that includes the rating; FIG. 6 is a block diagram of an embodiment of a computer system environment in which the systems and methods may be executed; and FIG. 7 is a block diagram of a computer system in which the systems and methods may be executed. In the appended figures, similar components and/or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a letter that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label. DETAILED DESCRIPTION The ensuing description provides embodiments only and is not intended to limit the scope, applicability, or configuration of the claims. Rather, the ensuing description will provide those skilled in the art with an enabling description for implementing the embodiments. It being understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the appended claims. FIG. 1 shows an illustrative embodiment of a contact center 100 . A contact center 100 comprises a central server 110 , a set of data stores or databases 114 containing contact or customer related information and other information that can enhance the value and efficiency of the contact, and a plurality of servers, namely a voice mail server 126 , an Interactive Voice Response unit or IVR 122 , and other servers 124 , an outbound dialer 128 , a switch 130 , a plurality of working agents operating packet-switched (first) telecommunication devices 134 - 1 to 134 -N (such as computer work stations or personal computers), and/or circuit-switched (second) telecommunication devices 138 - 1 to 138 -M, all interconnected by a local area network LAN (or wide area network WAN) 142 . The servers can be connected via optional communication lines 146 to the switch 130 . As will be appreciated, the other servers 124 can also include a scanner (which is normally not connected to the switch 130 or Web server), VoIP software, video call software, voice messaging software, an IP voice server, a fax server, a web server, an instant messaging server, and an email server) and the like. The switch 130 is connected via a plurality of trunks 150 to the Public Switch Telecommunication Network or PSTN 154 and via link(s) 152 to the second telecommunication devices 138 - 1 to M. A gateway 158 is positioned between the server 110 and the packet-switched network 162 to process communications passing between the server 110 and the network 162 . Referring to FIG. 2 , one possible configuration of the server 110 is depicted. The server 110 is in communication with a plurality of customer communication lines 200 a - y (which can be one or more trunks, phone lines, etc.) and agent communication line 204 (which can be a voice-and-data transmission line such as LAN 142 and/or a circuit switched voice line 146 ). The server 110 can include a Basic Call Management System or BCMS (not shown) and a Call Management System or CMS (not shown) that gathers call records and contact-center statistics for use in generating contact-center reports. The switch 130 and/or server 110 can be any architecture for directing contacts to one or more telecommunication devices. Illustratively, the switch and/or server can be a modified form of the subscriber-premises equipment disclosed in U.S. Pat. Nos. 6,192,122; 6,173,053; 6,163,607; 5,982,873; 5,905,793; 5,828,747; and 5,206,903, all of which are incorporated herein by this reference in their entirety for all that they teach; Avaya Inc.'s Definity™ Private-Branch Exchange (PBX)-based ACD system; MultiVantage™ PBX, CRM Central 2000 Server™, Communication Manager™, Business Advocate™, Call Center™, Contact Center Express™, Interaction Center™, and/or S8300™, S8400™, S8500™, and S8700™ servers; or Nortel's Business Communications Manager Intelligent Contact Center™, Contact Center—Express™, Contact Center Manager Server™, Contact Center Portfolio™, and Messaging 100/150 Basic Contact Center™. Typically, the switch/server is a stored-program-controlled system that conventionally includes interfaces to external communication links, a communications switching fabric, service circuits (e.g., tone generators, announcement circuits, etc.), memory for storing control programs and data, and a processor (i.e., a computer) for executing the stored control programs to control the interfaces and the fabric and to provide automatic contact-distribution functionality. The switch and/or server typically include a network interface card (not shown) to provide services to the serviced telecommunication devices. Other types of known switches and servers are well known in the art and therefore not described in detail herein. Referring again to FIG. 2 , included among the data stored in the server 110 is a set of contact queues 208 a - n and a separate set of agent queues 212 a - n . Each contact queue 208 a - n corresponds to a different set of agent skills, as does each agent queue 212 a - n . Conventionally, contacts are prioritized and are queued in individual ones of the contact queues 208 a - n in their respective orders of priority or are queued in different ones of a plurality of contact queues that correspond to a different priority. Likewise, each agent's skills are prioritized according to his or her level of expertise in that skill, and either agents are queued in individual ones of agent queues 212 a - n in their order of expertise level or are queued in different ones of a plurality of agent queues 212 a - n that correspond to a skill and each one of which corresponds to a different expertise level. Included among the control programs in the server 110 is an agent and contact selector 220 (referred to hereinafter simply as the contact selector 220 ). Contacts incoming to the contact center, which are temporarily held in contact queue 216 , are assigned by contact selector 220 to different contact queues 208 a - n based upon a number of predetermined criteria, including customer identity, customer needs, contact center needs, current contact center queue lengths, customer value, and the agent skill that is required for the proper handling of the contact. The queues 208 a - n are part of a larger contact queue 217 . The predetermined criteria may be obtained by either automatic or initial human interaction to determine the needs of the customer. These criteria can be used to initially evaluate whether the customer is having difficulty with an IVR script and conference the customer with an agent as described in conjunction with FIGS. 3 through 5 . Agents who are available for handling contacts are assigned to agent queues 212 a - n based upon the skills that they possess. An agent may have multiple skills, and hence may be assigned to multiple agent queues 212 a - n simultaneously. Furthermore, an agent may have different levels of skill expertise (e.g., skill levels 1-N in one configuration or merely primary skills and secondary skills in another configuration), and hence may be assigned to different agent queues 212 a - n at different expertise levels. Call vectoring is described in DEFINITY Communications System Generic 3 Call Vectoring/Expert Agent Selection (EAS) Guide, AT&T publication no. 555-230-520 (Issue 3, November 1993). Skills-based ACD is described in further detail in U.S. Pat. Nos. 6,173,053 and 5,206,903. Referring again to FIG. 1 , the gateway 158 can be Avaya Inc.'s, G250™, G350™ G430™, G450™, G650™, G700™, and IG550™ Media Gateways and may be implemented as hardware such as via an adjunct processor (as shown) or as a chip in the server. The first telecommunication devices 134 - 1 , . . . 134 -N are packet-switched and can include, for example, IP hardphones such as the Avaya Inc.'s, 1600™, 4600™, and 5600™ Series IP Phones™, IP softphones such as Avaya Inc.'s, IP Softphone™, Personal Digital Assistants or PDAs, Personal Computers or PCs, laptops, packet-based H.320 video phones and conferencing units, packet-based voice messaging and response units, and packet-based traditional computer telephony adjuncts. The second telecommunication devices 138 - 1 , . . . 138 -M are circuit-switched. Each of the telecommunication devices 138 - 1 , . . . 138 -M corresponds to one of a set of internal extensions Ext1, . . . ExtM, respectively. These extensions are referred to herein as “internal” in that they are extensions within the premises that are directly serviced by the switch. More particularly, these extensions correspond to conventional telecommunication device endpoints serviced by the switch/server, and the switch/server can direct incoming calls to and receive outgoing calls from these extensions in a conventional manner. The second telecommunication devices can include, for example, wired and wireless telephones, PDAs, H.320 video phones and conferencing units, voice messaging and response units, and traditional computer telephony adjuncts. Exemplary digital telecommunication devices include Avaya Inc.'s 2400™, 5400™, and 9600™ Series phones. It should be noted that the embodiments do not require any particular type of information transport medium between the switch or the server and the first and the second telecommunication devices, i.e., the embodiments may be implemented with any desired type of transport medium as well as combinations of different types of transport media. The packet-switched network 162 can be any data and/or distributed processing network, such as the Internet. The network 162 typically includes proxies (not shown), registrars (not shown), and routers (not shown) for managing packet flows. The packet-switched network 162 is in (wireless or wired) communication with an external first telecommunication device 174 via a gateway 178 , and the circuit-switched network 154 with an external (wired) second telecommunication device 180 and (wireless) third (customer) telecommunication device 184 . These telecommunication devices are referred to as “external” in that they are not directly supported as telecommunication device endpoints by the switch or server. The telecommunication devices 174 and 180 are an example of devices more generally referred to herein as “external endpoints.” In some configurations, the server 110 , network 162 , and first telecommunication devices 134 are Session Initiation Protocol or SIP compatible and can include interfaces for various other protocols such as the Lightweight Directory Access Protocol or LDAP, H.248, H.323, Simple Mail Transfer Protocol or SMTP, IMAP4, ISDN, E1/T1, and analog line or trunk. It should be emphasized that the configuration of the switch, server, user telecommunication devices, and other elements as shown in FIG. 1 is for purposes of illustration only and should not be construed as limiting the embodiments to any particular arrangement of elements. As will be appreciated, the central server 110 is notified via LAN 142 of an incoming contact by the telecommunications component (e.g., switch 130 , fax server, email server, web server, and/or other server) receiving the incoming contact. The incoming contact is held by the receiving telecommunications component until the server 110 forwards instructions to the component to forward or route the contact to a specific contact center resource, such as the IVR unit 122 , the voice mail server 126 , the instant messaging server, and/or first or second telecommunication device 134 , 138 associated with a selected agent. The server 110 distributes and connects these contacts to telecommunication devices of available agents based on the predetermined criteria noted above. When the central server 110 forwards a voice contact to an agent, the central server 110 also forwards customer-related information from databases 114 to the agent's computer work station for viewing (such as by a pop-up display) to permit the agent to better serve the customer. The agents process the contacts sent to them by the central server 110 . This embodiment is suited for a Customer Relationship Management (CRM) environment in which customers are permitted to use any media to contact a business. In a CRM environment, both real-time and non-real-time contacts must be handled and distributed with equal efficiency and effectiveness. In embodiments, included among the programs executing on the server 110 are an agent and contact selector 220 and agent IVR conference module 232 . The selector 220 and agent IVR conference module 232 are stored either in the main memory or in a peripheral memory (e.g., disk, CD ROM, etc.) or some other computer-readable medium of the center 100 . The contact selector 220 and agent IVR conference module 232 collectively effect an assignment between available contacts in a queue and available agents serving the queue in a way that tends to maximize contact center efficiency. The selector 220 uses predefined criteria in selecting an appropriate agent to service the contact. The agent IVR conference module 232 assigns services priorities to contacts and, as part of this function, identifies contacts as disconnected or transitory contacts and determines whether such contacts merit special treatment. The agent IVR conference module 232 provides instructions to the selector 220 to effect the special treatment. The agent IVR conference module 232 , based on one or more selected criteria, determines whether a contact should be placed in a conference with an agent to assist with an IVR. Special treatment includes providing the agent with materials or information to assist the customer, determine when and if the contact needs to have an agent assigned, etc. These and other embodiments are described in conjunction with FIG. 3 . An embodiment of the central server 110 (referred to as “server”) in the contact center 100 , which includes an agent IVR conference module 232 , is shown in FIG. 3 . Generally, the agent IVR conference module 232 of the central server 110 , which may be a computer system as described in conjunction with FIGS. 6 and 7 , includes one or more software modules, components, etc. that are operable to assist callers with an IVR. However, in embodiments, the modules, components, etc. described in conjunction with FIG. 3 are embodied in specially designed hardware, such as a application specific integrated circuit (ASIC) or field programmable gate array (FPGA). However, the central server 110 is hereinafter described as a computer system executing software to provide the functionality, but the embodiments are not limited to these examples as one skilled in the art will understand. An agent IVR conference system 232 is operable to communicate with a contact, an agent, a contact selector 220 , one or more skill queues 212 / 208 , and/or the interactive voice response unit 122 . The agent IVR conference system 232 is operable to monitor one or more customer contacts, which may have been placed in the contact queue 216 and then forwarded to or are using the interactive voice response unit 122 . The agent IVR conference system 232 can determine if the customer is having difficulty with the IVR script and may then either direct the contact selector 220 to route the contact into a conference that should include an IVR skilled agent in an agent queue 212 or simply send the contact to an agent. In other embodiments, the IVR script has the ability to direct a contact to an agent or conference with an agent. Thus, the customer is placed into a contact queue 217 and a skill queue 208 associated with IVR assistance. The agent is queued in the agent queue 212 , and the IVR system 122 may also be conferenced into the call. An embodiment of the IVR conference system 232 is as shown in FIG. 3 . Referring to FIG. 3 , an agent IVR conference system 232 may be a module or system operated by a server or processor. The agent IVR conference system 232 can include one or more modules that may be executed in hardware or software. These modules may communicate with one another to conduct the operations described herein. In embodiments, the agent IVR conference system 232 includes an error recognition module 302 , a suspension module 304 , an IVR database 306 , a conference call module 308 , a second database 310 and/or an IP transfer module 312 . Each of these modules will be described herein after. An error recognition module 302 is operable to monitor the IVR session conducted between the IVR response unit 122 and one or more customers operating telecommunication devices 174 / 180 . The error recognition module 302 can use one or more methods to determine if the customer is having trouble with the IVR script. In another embodiment, the IVR script/IVR application has the ability to monitor the IVR session and the functions of the error recognition module 302 are incorporated into the IVR script. In one embodiment, if the user presents one or more incorrect answers to responses in the IVR script, the error recognition module 302 can determine that the customer is having difficulty with the IVR script. If the customer is having trouble with the IVR script, the error recognition module 302 can signal the suspension module 304 that such difficulty has occurred. In embodiments, the error recognition module 302 may determine difficulty with the IVR script based on one or more predetermined rules stored in the rules database 310 . The suspension module 304 is operable to suspend the IVR script. Thus, the suspension module, upon receiving a signal from the error recognition module 302 , can send a signal to the IVR unit 122 to suspend the IVR script. Further, the suspension module 304 can also receive inputs or commands from an agent communication device 134 / 138 . Thus, the agent communication device 134 / 138 can control the function of the suspension module 304 . The agent can reinitiate the IVR script, continue the suspension, cancel the IVR session or do one or more other tasks by interacting with the suspension module 304 . An IVR database 306 can be any database as described in conjunction with FIGS. 6 and 7 . In embodiments, the IVR database 306 includes information about one or more communication sessions between the customer and the IVR unit 122 . This information can include customer information, IVR script information, information about responses to the current IVR script, questions asked during the IVR session, etc. Data stored within the IVR database 306 can be as described in conjunction with FIG. 4 . The IP transfer module 312 is operable to transfer information to the agent communication device 134 / 138 . In embodiments, the IP transfer module 312 can obtain information from the IVR database 306 or other data sources to send to the agent communication device 134 / 138 . This information can include IVR script information, information about the current IVR session, information about the customer, or other information needed or requested by the agent communication device 134 / 138 to conduct or conference with the customer about the IVR script. The rules database 310 is operable to store information about how to determine when an agent should assist with an IVR script. These rules may be predetermined by the user or standard for all Agent IVR Conference Systems 232 . Example rules can include if the user incorrectly answers a question two times, answers two sequential questions incorrectly, etc. then assistance is needed; if a user presses “0”, to obtain human assistance, two or more time in response to a question, then assistance is needed; or if a user goes back or forward through one or more questions, then assistance is needed. More rules are possible and contemplated. The rules can be categorized based on the customer, context of the assistance, or other data to better determine when assistance is required. Thus, the rules database 310 may provide the error recognition module 302 with some or all of the rules depending on the call. A conference call module 308 is operable to conference the customer telecommunication device 170 / 180 with the IVR unit 122 and the agent communication device 134 / 138 . Thus, the conference call module 308 can bring the three different entities into one conference call and allow the agent to direct the customer actions with respect to the IVR script. The conference call module 308 may also conference in other agents or customers as needed. The conference call module 308 begins a conference upon direction of the error recognition module 302 or suspension module 304 when it is determined that a conference is needed because a customer is having trouble with an IVR script. The conference call module 308 is operable to communicate with the contact queue 216 , the agent and contact selector 220 , and one or more queues 208 / 212 to initiate and conduct a conference call. An embodiment of a data structure 400 that may be received, sent, or stored while determining whether a caller requires assistance with an IVR session is shown in FIG. 4 . The one or more data structures described in conjunction with FIG. 4 can be any type of data structure including an object, a field, or other data structure in a relational database, a flat file database, etc. Here, each field within the data structure 400 is described as a portion of the data structure 400 . However, it should be understood by one skilled in the art, the portion can be a field, attribute, or other data structure according to the type of database used. The portions may include data associated with IVR process metadata 402 , customer information 404 , a first message 406 , a first response 408 , a second message 410 , and a second response 412 . There may be more or fewer items of data in the data structure 400 as represented by ellipses 414 . Further, each IVR session may include a separate data structure 400 that may be stored in the IVR database 306 . However, only a single data structure 400 is shown in FIG. 4 in order for simpler discussion and description of the data structure. The IVR process metadata 402 can describe one or more items of information about the current IVR session or IVR script. For example, the IVR process metadata 402 can include a unique ID assigned to the IVR session, can include an identifier associated with the IVR script being executed during the IVR session, or other information that may be pertinent to the agent when the agent is trying to help the customer with the IVR session. The IVR process metadata 402 may be collected from the IVR unit 122 and stored in the IVR process metadata portion 402 . The agent may access the IVR process metadata 402 on an agent communication device 134 / 138 during the conference IVR session. Customer information 404 can include one or more items of information about the customer currently engaged in the IVR session. The customer information 404 can include the customer's name, address, phone number, previous calls, or other information stored by the server 110 . Customer information 404 may be taken before the IVR session, obtained during the IVR session, or stored during previous calls and retrieved by the Agent IVR Conference System 232 . The data structure 400 may also store one or more messages and responses that are part of the IVR script. For example, the IVR session may have requested information in a first message 406 and a second message 410 . The customer may have given information in response 408 and response 412 . By having the message and responses from the IVR script stored in the data structure 400 , the agent can deduce where the customer may have entered incorrect information or had trouble with the IVR script. Thus, the entire message/response session with the IVR script may be stored in one or more portions of the data structure 400 . An embodiment of a method for conducting an agent conference IVR session is shown in FIG. 5 . Generally, the method 500 begins with a start operation 502 and terminates with an end operation 518 . While a general order for the steps of the method 500 is shown in FIG. 5 , the method 500 can include more or fewer steps or arrange the order of the steps differently than those shown in FIG. 5 . The method 500 can be executed as a set of computer-executable instructions executed by a computer system and encoded or stored on a computer readable medium. Hereinafter, the method 500 shall be explained with reference to the systems, components, modules, software, data structures, etc. described in conjunction with FIGS. 1-4 . The server 110 receives a customer contact from a telecommunication device 174 / 180 , in step 504 . The customer contact can be a contact of any type of media but, in embodiments described hereinafter, is described as telephone call received through one or more networks 162 / 154 , possibly a switch 130 , a bus 142 , a gateway 178 , 158 , or one or more other devices. The customer contact can be directed from the server 110 into a contact queue 216 . The server 110 may then determine that the customer contact is suitable for sending to an IVR unit 122 . The server 110 may then send the contact to the IVR unit 122 to have the IVR unit 122 interact with the customer. The IVR unit 122 can then present the customer with an IVR script, in step 506 . The IVR script may include one or more questions and require interactive responses from the customer. The customer may be able to enter information through voice responses or using a key pad. This information may be recorded by the IVR unit 122 and presented to the server 110 . The server 110 may receive the information from the IVR unit 122 and provide it to an agent IVR conference system 232 . The error recognition module 302 of the agent IVR conference system 232 can analyze the information received from the IVR response unit 122 , to determine if the user is having trouble with the IVR script, in step 508 . Further, the agent IVR conference system 232 can store the received information in the IVR database 306 , in a data structure 400 . As the customer is interacting with the IVR unit 122 the error recognition module 302 can analyze the information to determine if the user is having trouble with the IVR script. For example, the error recognition module 302 can retrieve one or more rules from the rules database 310 and apply the rule(s) to the IVR session. For example, the error recognition module 302 can determine if the customer has entered one or more incorrect answers during the IVR script. If a customer has sequentially entered two or more incorrect answers, the customer may be having difficulty. In other examples, the error recognition module 302 can recognize the user has requested an operator or some other help during the IVR session. If the error recognition module determines that the user is having trouble with the IVR, step 508 proceeds “YES” to step 510 . If the error recognition module determines that the user is not having trouble with the IVR, step 508 proceeds “NO” to step 516 to continue the IVR while the error recognition module 302 continues to monitor the session. A suspension module 304 can then receive a signal from the error recognition module 302 ; the signal can indicate that the user is having trouble with the IVR script. The signal directs the suspension module 304 to suspend the IVR script. The suspension module 304 may then send a signal to the IVR unit 122 to suspend the script. Further, the error recognition module 302 can send a signal to the agent and contact selector 220 to queue an agent into an agent queue 212 associated with IVR assistance. The agent, in embodiments, has skills in directing customers through IVR scripts. Further, the error recognition module 302 directs the agent and contact selector to queue the contact into a queue 208 to be placed in the conference. The error recognition module 302 then instructs the conference call module 308 to conference in the agent, customer, and IVR session into a conference call. The agent contact selector 220 queues an IVR skilled agent into a skill queue 212 , in step 510 . The agent contact selector 220 may then inform the customer, in the queue 208 , that the agent is going to be included in the contact. In embodiments, one of the skill queues 212 is related to IVR systems. Further, one of the contact queues 208 is associated with help with the IVR session. When the agent is available, the agent contact selector 220 can inform the agent IVR conference system 232 to conduct the conference. Upon receiving a signal that the agent is available, the conference call module 308 can create a conference call between the customer telecommunication device 174 / 180 , the IVR unit 122 , and the agent communication device 134 / 138 , in step 512 . The conference call includes each of the three entities and allows the agent to communicate with the customer about the IVR script. Further, the agent is operable to reinitiate the IVR script by instructing the suspension module 304 to start the IVR script, may continue to suspend the IVR script, may provide a different IVR script, may change or instruct the IVR script to change its execution or behavior, or do other actions to help the customer with their needs in providing information to the server 110 through the IVR session. At some point thereinafter, the agent can disengage from the conference. The agent may disengage if the customer is able to then perform the rest of the IVR script and is allowed to complete the IVR script on their own, or may disengage if the agent handles the customer's call rather than continue with the IVR script. In embodiments, the method 500 shows the continuation of the method 500 if the agent disengages because the customer continues with the IVR script. Thus, the conference call module 308 can determine if the agents disengaged, in step 514 . If the agent is disengaged, step 514 proceeds “YES” to step 516 . If the agent is not disengaged, step 514 proceeds “NO” back to step 512 where the conference continues with the agent, the IVR unit 122 , and the customer. In step 516 , the customer continues with the IVR script. Thus, the customer is able to answer further questions and respond to the questions until the IVR script is completed, a new IVR script is started, or the customer needs help again. The information about the continued IVR session continues to be stored in the data structure 400 , and the information continues to be sent from the IVR unit 122 to the agent IVR conference system 232 . The customer may need help again in which case the method 500 may start over at step 508 . The computers, computer systems, servers, devices, and/or components that are described herein and that may execute the processes described herein may be as described in conjunction with FIGS. 6 and 7 . FIG. 6 illustrates a block diagram of a computing environment 600 . The system 600 includes one or more computers 605 , 610 , and 615 . The computers 605 , 610 , and 615 may be general purpose personal computers (including, merely by way of example, personal computers and/or laptop computers running various versions of Microsoft Corp.'s Windows® and/or Apple Corp.'s Macintosh® operating systems) and/or workstation computers running any of a variety of commercially-available UNIX® or UNIX-like operating systems. These computers 605 , 610 , 615 may also have any of a variety of applications, including for example, database client and/or server applications, and web browser applications. Alternatively, the computers 605 , 610 , and 615 may be any other electronic device, such as a thin-client computer, mobile telephone, mobile device, Internet-enabled mobile telephone, and/or personal digital assistant, capable of communicating via a network (e.g., the network 620 described below) and/or displaying and navigating web pages or other types of electronic data. Although the exemplary system 600 is shown with three computers, any number of computers may be supported. System 600 further includes a network 620 . The network 620 may can be any type of network familiar to those skilled in the art that can support data communications using any of a variety of commercially-available protocols, including without limitation TCP/IP, SNA, IPX, AppleTalk, and the like. Merely by way of example, the network 620 maybe a local area network (“LAN”), such as an Ethernet network, a Token-Ring network and/or the like; a wide-area network; a virtual network, including without limitation a virtual private network (“VPN”); the Internet; an intranet; an extranet; a public switched telephone network (“PSTN”); an infra-red network; a wireless network (e.g., a network operating under any of the IEEE 802.11 suite of protocols, the Bluetooth® protocol known in the art, and/or any other wireless protocol); and/or any combination of these and/or other networks. The system 600 may also include one or more server computers 625 and 630 . The server computers 625 and/or 630 can represent the customer service server 102 . One server may be a web server 625 , which may be used to process requests for web pages or other electronic documents from user computers 605 , 610 , and 620 . The web server can be running an operating system including any of those discussed above, as well as any commercially-available server operating systems. The web server 625 can also run a variety of server applications, including HTTP servers, FTP servers, CGI servers, database servers, Java servers, and the like. In some instances, the web server 625 may publish operations available operations as one or more web services. The system 600 may also include one or more file and or/application servers 630 , which can, in addition to an operating system, include one or more applications accessible by a client running on one or more of the user computers 605 , 610 , 615 . The server(s) 630 may be one or more general purpose computers capable of executing programs or scripts in response to the user computers 605 , 610 and 615 . As one example, the server may execute one or more web applications. The web application may be implemented as one or more scripts or programs written in any programming language, such as Java™, C, C# or C++, and/or any scripting language, such as Perl, Python, or TCL, as well as combinations of any programming/scripting languages. The application server(s) 630 may also include database servers, including without limitation those commercially available from Oracle, Microsoft, Sybase™, IBM™ and the like, which can process requests from database clients running on a user computer 605 . The web pages created by the web application server 630 may be forwarded to a user computer 605 via a web server 625 . Similarly, the web server 625 may be able to receive web page requests, web services invocations, and/or input data from a user computer 605 and can forward the web page requests and/or input data to the web application server 630 . In further embodiments, the server 630 may function as a file server. Although for ease of description, FIG. 6 illustrates a separate web server 625 and file/application server 630 , those skilled in the art will recognize that the functions described with respect to servers 625 , 630 may be performed by a single server and/or a plurality of specialized servers, depending on implementation-specific needs and parameters. The system 600 may also include a database 635 . The database 635 may reside in a variety of locations. By way of example, database 635 may reside on a storage medium local to (and/or resident in) one or more of the computers 605 , 610 , 615 , 625 , 630 . Alternatively, it may be remote from any or all of the computers 605 , 610 , 615 , 625 , 630 , and in communication (e.g., via the network 620 ) with one or more of these. In a particular set of embodiments, the database 635 may reside in a storage-area network (“SAN”) familiar to those skilled in the art. Similarly, any necessary files for performing the functions attributed to the computers 605 , 610 , 615 , 625 , 630 may be stored locally on the respective computer and/or remotely, as appropriate. In one set of embodiments, the database 635 may be a relational database, such as Oracle 10i®, that is adapted to store, update, and retrieve data in response to SQL-formatted commands. FIG. 7 illustrates one embodiment of a computer system 700 upon which the test system may be deployed or executed. The computer system 700 is shown comprising hardware elements that may be electrically coupled via a bus 755 . The hardware elements may include one or more central processing units (CPUs) 705 ; one or more input devices 710 (e.g., a mouse, a keyboard, etc.); and one or more output devices 715 (e.g., a display device, a printer, etc.). The computer system 700 may also include one or more storage devices 720 . By way of example, storage device(s) 720 may be disk drives, optical storage devices, solid-state storage devices, such as a random access memory (“RAM”) and/or a read-only memory (“ROM”), which can be programmable, flash-updateable, and/or the like. The computer system 700 may additionally include a computer-readable storage media reader 725 ; a communications system 730 (e.g., a modem, a network card (wireless or wired), an infra-red communication device, etc.); and working memory 740 , which may include RAM and ROM devices as described above. In some embodiments, the computer system 700 may also include a processing acceleration unit 735 , which can include a DSP, a special-purpose processor and/or the like The computer-readable storage media reader 725 can further be connected to a computer-readable storage medium, together (and, optionally, in combination with storage device(s) 720 ) comprehensively representing remote, local, fixed, and/or removable storage devices plus storage media for temporarily and/or more permanently containing computer-readable information. The communications system 730 may permit data to be exchanged with the network 720 and/or any other computer described above with respect to the system 700 . Moreover, as disclosed herein, the term “storage medium” may represent one or more devices for storing data, including read only memory (ROM), random access memory (RAM), magnetic RAM, core memory, magnetic disk storage mediums, optical storage mediums, flash memory devices, and/or other machine readable mediums for storing information. The computer system 700 may also comprise software elements, shown as being currently located within a working memory 740 , including an operating system 745 and/or other code 750 , such as program code implementing the components and software described herein. It should be appreciated that alternate embodiments of a computer system 700 may have numerous variations from that described above. For example, customized hardware might also be used and/or particular elements might be implemented in hardware, software (including portable software, such as applets), or both. Further, connection to other computing devices such as network input/output devices may be employed. In the foregoing description, for the purposes of illustration, methods were described in a particular order. It should be appreciated that in alternate embodiments, the methods may be performed in a different order than that described. It should also be appreciated that the methods described above may be performed by hardware components or may be embodied in sequences of computer-readable or machine-executable instructions, which may be used to cause a machine, such as a general-purpose or special-purpose processor or logic circuits programmed with the instructions to perform the methods. These computer-readable or machine-executable instructions may be stored on one or more machine readable mediums, such as CD-ROMs or other type of optical disks, floppy diskettes, ROMs, RAMs, EPROMs, EEPROMs, magnetic or optical cards, flash memory, or other types of computer-readable or machine-readable mediums suitable for storing electronic instructions. Alternatively, the methods may be performed by a combination of hardware and software. Furthermore, embodiments may be implemented by hardware, software, firmware, middleware, microcode, hardware description languages, or any combination thereof. When implemented in software, firmware, middleware or microcode, the program code or code segments to perform the necessary tasks may be stored in a machine readable medium such as storage medium. A processor(s) may perform the necessary tasks. A code segment may represent a procedure, a function, a subprogram, a program, a routine, a subroutine, a module, a software package, a class, or any combination of instructions, data structures, or program statements. A code segment may be coupled to another code segment or a hardware circuit by passing and/or receiving information, data, arguments, parameters, or memory contents. Information, arguments, parameters, data, etc. may be passed, forwarded, or transmitted via any suitable means including memory sharing, message passing, token passing, network transmission, etc. Also, it is noted that the embodiments were described as a process which is depicted as a flowchart, a flow diagram, a data flow diagram, a structure diagram, or a block diagram. Although a flowchart may describe the operations as a sequential process, many of the operations can be performed in parallel or concurrently. In addition, the order of the operations may be re-arranged. A process is terminated when its operations are completed, but could have additional steps not included in the figure. A process may correspond to a method, a function, a procedure, a subroutine, a subprogram, etc. When a process corresponds to a function, its termination corresponds to a return of the function to the calling function or the main function. Specific details were given in the description to provide a thorough understanding of the embodiments. However, it will be understood by one of ordinary skill in the art that the embodiments may be practiced without these specific details. For example, circuits may be shown in block diagrams in order not to obscure the embodiments in unnecessary detail. In other instances, well-known circuits, processes, algorithms, structures, and techniques may be shown without unnecessary detail in order to avoid obscuring the embodiments. While illustrative embodiments have been described in detail herein, it is to be understood that the inventive concepts may be otherwise variously embodied and employed, and that the appended claims are intended to be construed to include such variations, except as limited by the prior art.

A system engages a live agent in a multi-party call type arrangement with the user and an Interactive Voice Response (IVR) unit when the user has difficulty with the IVR. The agent is provided with information about the IVR process being executed and the user's input. When the agent is introduced into the call, the agent does not take over the IVR session, but the agent helps direct the user to provide the correct input(s) to the IVR session. Once the issue is corrected, the agent can remove themself from the customer/IVR dialog. As a consequence: the user continues their self-service transactions in the IVR, and the user is better educated on how to navigate the IVR in the future. Further, agent resources are spared from further interaction with the user, and the user is less likely to have a negative opinion of the IVR.