Abstract:
A compact appliance providing high resolution display capability in an ergonomically designed package. Subassemblies of the device are mechanically coupled to avoid interference between a user&#39;s hands and face while the device is used, while concurrently providing ergonomically located control for substantially all functions of the device.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention relates to ergonomic hand held devices. More specifically, the invention relates to user interface display and input technologies in a hand held electronic device. 
   2. Background 
   Hand held devices with some level of display capability including hand held computers, personal digital assistants (“PDA&#39;s”), cell phones and digital cameras. Displays on hand held devices suffer from a variety of deficiencies. Among these deficiencies are poor resolution, small size and poor readability under both bright and dim ambient conditions. Moreover, these limitations are additive in that small size contributes to poor readability and necessitates reduced resolution. 
   Digital cameras are increasingly common. Typical digital cameras have a view finder and also a display on which pictures taken may be viewed, typically at a reduced resolution. On some cameras, the display may be used as a substitute view finder for framing the picture to be taken. However, most of these displays suffer from severe degradation as a result of ambient light in bright environments. Even for the camera on which such displays are suitable view finders, the display tends to be inferior to a view with the naked eye and difficult or uncomfortable to use for long-term viewing. 
   Also, digital cameras and common hand-held devices such as hand-held computers, etc., have relatively poor ergonomics in existing designs. For example, typical digital cameras have a generally rectangular form factor in which it is difficult to get one&#39;s eye to the view finder without interference from the hand holding the camera. Moreover, holding the camera in a ready position is relatively uncomfortable over time. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     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. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean at least one. 
       FIG. 1  is a right perspective view of a camera of one embodiment of the invention in a right handed deployed orientation. 
       FIG. 2  is a rear right perspective view of the embodiment of  FIG. 1 . 
       FIGS. 3-5  are front, side and rear elevational views of the embodiment of  FIG. 1  in a stowed orientation. 
       FIG. 6  shows deployment of the device in one embodiment of the invention. 
       FIG. 7  is a sectional view of one embodiment of the invention. 
       FIGS. 8A &amp; 8B  are sectional views of one embodiment in a stowed orientation. 
       FIG. 9  is a block diagram of an electronic subsystem of one embodiment of the invention. 
       FIG. 10  is a bottom rear perspective view of an embodiment of the invention. 
       FIG. 11  is a top front perspective view of one embodiment of the device of  FIG. 10 . 
       FIG. 12  shows a view of the display of one embodiment of the invention. 
       FIG. 13  shows a view of the display with a virtual key board of one embodiment of the invention. 
       FIGS. 14A &amp; 14B  are a block diagram of a hand held device of one embodiment of the invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  is a right perspective view of a camera of one embodiment of the invention in a right handed deployed orientation. In one embodiment, the camera includes three main subassemblies: a grip  102 , a display assembly  104  and an optic subassembly including lens  106 . The subassemblies exist in defined mechanical relationships to enhance ergonomics of the device. Lens  106  resides in lens barrel  120  which telescopes from lens housing  118 . Lens  106  is in optical communication with an image sensing array (ISA) (not shown) such that when a shutter release occurs, the ISA captures an image as seen by the lens  106 . In one embodiment, lens  106  is a zoom lens driven by a motor (not shown). It is expected that some embodiments will also include autofocus capabilities. 
   A grip  102  is angled forward in the deployed orientation to accommodate comfortable wrist angles for a user. In one embodiment, a majority of the electronic components of the camera will reside within the grip  102 . The electronic requirements for digital image capture are generally known. A trigger  108  is provided coupled to grip  102  to provide a shutter release to activate image capture. Shutter release may be something of a misnomer in the context of some digital cameras. As used herein, “shutter release” means the mechanism actuated by a user to initiate a capture of an image. The trigger is positioned to be easily actuated by the index finger of a user. A release button  110  is provided on the grip  102  to assist in deploying the device into a deployed orientation from a stowed orientation. This transition is discussed in detail below in connection with  FIG. 6 . A data port  112  is also provided on the grip. A data port  112  may be a Universal Serial Bus (USB) port, an IEEE 1394 port, an infrared (IR) port, or any other suitable data port. A power port  132  may be provided. Alternatively, a battery  134  may power the device. 
   A display assembly  104  is rotatably mounted to the lens housing such that display assembly  104  can rotate about the lens housing to a plurality of positions. In one embodiment, a plurality of positions are detented around the lens housing to correspond to expected angles relative to the grip to provide comfortable viewing for a user. Because the display assembly  104  extends laterally away from the grip, a user&#39;s hand will be beside rather than in front of a user&#39;s face during use, thereby relieving interference with the user&#39;s face, breathing and talking. 
   In one embodiment, a display assembly  104  can rotate a full 360°. In another embodiment, the display assembly can rotate through an arc of less than 360°, but enough to provide a plurality of sustainable locations around the arc (possibly detented) for either right or left handed use. As shown in  FIG. 1 , the display assembly  104  forms a substantially right angle with grip  102 . It is expected that use of the display assembly at a position in which it forms an obtuse angle with the grip will provide even greater comfort for many users. In one embodiment, the device has ball bearing detents to retain the display assembly at 90° and 120° (relative to the grip) for both right-handed and left-handed use. In another embodiment, magnetic detents may be used. As an alternative to detented positions, the display assembly may be held in a number of positions relative to the lens housing by passive frictional engagement or active clamping between components of the device. 
   Display assembly  104  includes a back plate  124  that provides a window  116  through which a photo flash (not shown) residing within the display assembly may be used to illuminate a target of the camera. Because, in operation, the flash is disposed a significant lateral distance from the lens  106 , illumination errors, such as red eye, are significantly reduced. The display assembly  104  is biased so that the back plate  124  engages rim  126  in the deployed orientation. Rod  114  provides a shaft which may pass through back plate  124  in opposition to the bias within display assembly  104  when the display assembly is stowed. The bias may be provided by a spring about the rod  114 , a spring located elsewhere, or any other manner in which a mechanical bias force may be exerted on the back plate  124 . In one embodiment, the relative position of the back plate in relation to the remainder of the display assembly  104  is maintained possibly by a motor driven mechanical arm that retracts in response to a signal that the device is transitioning to a stowed orientation. 
     FIG. 2  is a rear right perspective view of the embodiment of  FIG. 1 . Display assembly  104  provides a binocular display. Binocular displays are believed superior to monocular displays as they reduce eye strain. However, monocular displays are deemed within the scope and contemplation of the invention. A pair of lenses  204  are retained fixed within the display assembly  104 . A pair of display elements  206  are biased to be a desired focal distance from the lenses  204  when the display assembly  104  is in the deployed orientation. That focal distance is defined by the rim  126  which engages the back plate  124  as a result of the bias described above. In this manner, a binocular view is presented to the eyes of a user. Display elements may be, for example, liquid crystal displays (LCDs), organic light emitting diode (OLED) displays, Liquid Crystal On Silicon (LCOS) displays, electroluminescent (EL) displays or retinal scanning lasers. 
   In one embodiment, a sensor is used to sense the angular orientation of the display assembly relative to the grip and lens. Based on that angular orientation, the image displayed on the display elements  206  is adjusted to provide consistent presentation. The ISA is typically fixed within, for example, the lens housing. Accordingly, some embodiments employ a sensor to identify the relative position of the ISA and the display assembly to adjust the image on the display assembly to accurately correspond to the view of the ISA. In one embodiment, the ISA orientation is fixed relative to the grip  102  such that changing the angle between grip  102  and display assembly  104  transitions between landscape and portrait views. Depending on the expected use angle, the ISA may be mounted at an angle within the grip so that at the expected deployed orientation, the ISA would be aligned with a horizontal reference plane. 
   A pointer button  208  is provided within a breech  130  of the grip  102 . When the breech  130  is closed (as discussed below), the pointer button  208  is not exposed. When the breech  130  is open, the pointer button  208  is located for easy use by a user&#39;s thumb while the device is being held by grip  102 . The pointer button  208  may be used to activate various functions of the device through, for example, pull down menus, icons, a virtual keypad, or other common graphical user interface mechanisms that may be presented on the display elements  206 . 
   In one embodiment, through on screen manipulation via the pointer button, substantially all functions of the device may be used with only the pointer button  208  and the trigger  108 . In one embodiment, this allows editing of images captured including additions of possible captions or other associated text. In an embodiment, zoom and/or focus of the lens  106  is controlled through on-screen virtual manipulation. In one embodiment, the trigger  108  is deemed always on when the display assembly is in the deployed orientation. Accordingly, any actuation of the trigger when the display is deployed causes an image capture to occur. 
   Grip  102  also includes a plurality of memory card slots  210  for memory of the same media type. In one embodiment, four memory card slots are present, more or fewer are also within the scope and contemplation of the invention. In embodiments having plural memory card slots, plural cards may be concurrently attached and may be selected electronically by a processor within the device. 
     FIGS. 3-5  are front, side and rear elevational views of the embodiment of  FIG. 1  in a stowed orientation. In one embodiment, in the stowed orientation, a device has a height of 27 mm, a width of 60 mm and a length of 112 mm. A display assembly sleeves over the grip as the rod  114  transitions through back plate  124  until the display assembly  104  locks in place along intersection  402 . In one embodiment, a hook on the rod  114  engages a latch internal to the grip (shown in  FIG. 8B ). It is expected that as much as 75% of the deployed volume of the display assembly can be overlapped with the grip in the stowed orientation. Also evident in  FIG. 4  is the gap  404  between grip  102  and lens housing  118  which permits the grip  102  to tilt forward in the deployed orientation. This forward tilt is believed to provide superior comfort in terms of wrist angle over either a vertical or a backward tilting grip. The grip may have a plurality of sustainable tilt angles. Similar to the display, these may be maintained by detents, frictional engagement between the parts or active clamping. 
     FIG. 6  shows deployment of the device in one embodiment of the invention. From the stowed orientation shown at  600 , actuation of release  110  causes the display assembly to transition away from the grip. Concurrently, an expander within the display assembly causes the assembly to expand to its deployed volume at  602  by biasing the remainder of the assembly away from the back plate. Both the transition and the expansion may be driven by springs within the grip  102  and display assembly  104 , respectively. Alternatively, one or both may be caused by a motor driven arm or other similar mechanism. The transition during the first stage of deployment clears the display assembly  104  from the lens housing  118  so that the display assembly  104  is free to be manually rotated about the lens housing  118  as shown at  604 . After the display assembly is disengaged and rotated away, the grip  102  may be manually tilted forward to close (or partially close) the gap  404  and open the breech  130  as shown at  606 . As previously noted, in one embodiment, opening the breech  130  is required to provide access to pointer button  208 . It is also within the scope and contemplation of the invention to provide the grip with a bias assist in transitioning to the deployed orientation. 
     FIG. 7  is a sectional view of one embodiment of the invention. Memory card  702  and detents  704  that define the angles off the perpendicular at which the grip  102  may be retained can be seen within grip  102 . The axis of rotation  706  of the display assembly  104  may also be seen. In one embodiment, the pointer button  208  is movable within a defined region and the region is absolutely mapped to the display elements. Accordingly, anytime the pointer button  208  is at a point x with the region, the cursor will be at a corresponding point y on the display. Stated differently, there is an exactly 1 to 1 mapping between locations on the display and positions of the pointer within the region. 
     FIG. 8A  is a sectional view of one embodiment in a stowed orientation. As shown, in the stowed orientation, spring  802  is compressed along post  114  such that the display elements  206  are substantially adjacent to lenses  204 . This permits the display assembly to overlap the grip  102  by an overlap distance  800 , which permits a significantly more compact device in the stowed orientation. 
   In one embodiment, pointer button  208  has a shaft  814 , a cap  812  and a point  804 . The cap  812  is larger than a bore  820  that defines the area in which pointer button  208  may move. A washer  806  holds the pointer button within the bore  820  and is movable such that the shaft  814  may move from one side of the bore  820  to the other. Point  804  may contact a resistive pad  808  that maps to the display. A click dome  810  may underly the resistive pad  808  so that pressure on the cap  812  actuates the click dome  810 . Alternatively, point  804  may provide optical or capacitive coupling to an underlying sensor pad that correlates the pointer location on the display with the location of the point within the area. 
     FIG. 8B  is a sectional view of one embodiment in a stowed orientation. A hook of rod  114  engages internal catch  850  to retain the display assembly  104  in the stowed orientation. By depressing the release button (not shown in  8 B), catch  850  pivots on a lever arm and releases the hook of rod  114 . Bias spring  802  then transitions the display assembly  104  to the deployed volume as discussed above. 
     FIG. 9  is a block diagram of an electronic subsystem of one embodiment of the invention. The processor  900  is provided to control the operation of the device. The processor drives data to displays  904  from an Image Sensing Array (ISA)  908 . The ISA  908  may be a complimentary metal oxide semiconductor (CMOS) sensor, a charge coupled device (CCD) or any other high resolution image sensing array. By providing such a high resolution (greater than 1 megapixel), users are better able to identify the quality of image capture through local viewing. One embodiment provides a display that permits local viewing at substantially the capture resolution. The processor  900  also provides control signaling to displays  904  based on information from the pointer interface  918  and orientation sensor  916 . The orientation sensor  916  senses the orientation of the display assembly relative to the axis of rotation and also relative to the ISA. Based on that orientation, the processor  900  is able to adjust the displays to maintain a consistent orientation of the images displayed. The trigger input  914  provides an indication to the processor that a readout of the image sensing array  908  may be needed. After a capture occurs, the processor  900  reads out the ISA  908  to one of the memory cards  902 . The processor also generally controls all data flow in or out of the data port  912  and to and from the memory cards  902 . The processor may also control the lens motor  906  based on inputs from an auto focus module  910  and/or directions from the pointer interface  918 . 
   In one embodiment, the device may be a web appliance rather than a digital camera. In such an embodiment, while the primary mechanical relationship remains the same, the lens  106  may be replaced by a radio and web interface module to provide for example, wireless access to the internet or another distributed network. The processor may execute a web browser, and the user may interact with the internet through the pointer button  208  and the trigger  108 . In one embodiment, the trigger  108  performs the execute function analogous to a “return” or “enter” from a conventional keyboard. Other aspects of the device and the mechanical properties may be substantially as described above. In another embodiment, a radio having a form factor of a memory card may be introduced into one of the memory card slots, thereby enabling the camera to access a distributed network, or function in the traditional manner. 
     FIG. 10  is a bottom rear perspective view of an embodiment of the invention. A digital camera with a binocular display resides within a compact housing  1002 . The housing defines a pair of lobe hand grips  1028 . These hand grips  1028  may be coated within an elastomeric material to provide improved grip and holding comfort for a user. The housing  1002  defines openings in which a pair of binocular lenses  1004  may be disposed. The lenses  1004  are in the optical path of a pair of megapixel displays, which also serve as a viewfinder. As such, a user looking through the lenses is provided a high-resolution binocular view of what the camera lens currently sees. An audio output speaker  1040  may also be provided. A microphone may also be provided to permit audio annotation to be associated with an image captured. 
   A visor  1010  is coupled to the housing  1002  to rest on a user&#39;s forehead when the device is held by a user and thereby maintain an appropriate focal distance between a user and the lenses  1004 . In one embodiment, the cross-dimension (and therefore, the focal distance) is adjustable within a range by using a hinge and slide attachment mechanism. By engaging a user&#39;s forehead rather than the soft tissue around the eyes, comfort is enhanced and usability by users wearing glasses is also facilitated. The visor  1010  also serves as a light shield, reducing ambient light contamination, and therefore, degradation of the displayed image from the user&#39;s perspective. In one embodiment, the visor  1010  is hinged to the housing and pivots between an open position (shown) and a closed position to protect the lenses  1004  when not in use. In one such embodiment, the visor  1010  transitioning to the closed position causes the display/viewfinder to enter an inactive state. Conversely, opening the visor  1010  activates the display. In one embodiment, if no display event occurs for a time period, the display automatically transitions to an inactive state to save power. In one such embodiment, the display may be reactivated by cycling the visor  1010 , e.g., closing the visor  1010  and reopening it. 
   The housing  1002  also defines a chamber for a battery pack  1038 . In one embodiment, the battery pack may be a lithium ion battery pack. Other batteries are within the scope and contemplation of the invention. 
   In one embodiment, a left and a right hand finger pad  1020  and  1022 , respectively, provide pointer functionality on the display. Each finger pad may reside in a region  1016 ,  1018 , which is absolutely mapped to at least a portion of the display. 
   In one embodiment, the regions are mapped to, for example, the right and left-hand side of the display and do not overlap. Alternatively, each region could be mapped to the entire display or have some overlap, e.g. each mapped to two-thirds of the display. Typically, the regions  1016 ,  1018  will be shaped and oriented similarly to the area of the display to which they map. Each finger pad  1020 ,  1022  is moveable in two orthogonal directions within its respective region. The finger pad may be actuated by pressing the pad substantially perpendicular to the two orthogonal directions of movement. For example, if the finger pad moves in an x-y plane, actuation occurs when the pad is pressed in a z direction. Additionally, each finger pad may be provided with a sensor  1024 ,  1026  to indicate when a user is engaging the respective finger pad. Such sensors may include biometric sensors, e.g., to detect galvanic skin response, pressure sensors, temperature sensors, or any other sensors which would give a reasonable indication that a user is engaging the finger pad  1020 ,  1022 . In one embodiment, when both finger pads are engaged, each finger pad is mapped to half the display, but if only one finger pad is engages, the finger pad is remapped to the entire display. 
   In one embodiment, the regions  1016 ,  1018  may be textured to provide a tactile indication of a location within the region. Alternatively, finger pads  1020 ,  1022  may be coupled to a mechanical drive to provide a tactile indication of a property of the virtual environment of a cursor on the display. Two pointer buttons that are not absolutely mapped are also within the scope and contemplation of the invention. Alternatively, a pointing button may be supplied proximate to the shutter release thereby also permitting use by either hand. One or more selection buttons may also be provided. The use of these user interface devices is explained in more detail below with reference to  FIGS. 12 and 13 . 
     FIG. 11  is a top front perspective view of one embodiment of the device of  FIG. 10 . On the opposite side of housing  1002  as the visor  1010 , a door  1140  may be hinged to the housing  1002  to conceal various ports and slots. Behind the door  1140 , the housing  1002  may define a memory card slot  1130  to accept any conventional memory card, such as compact flash, Bluetooth, or Microdrive disks. A secure digital (“SD”) card slot  1134  may also reside behind the door. A USB or other suitable data port  1132  may be also provided. A power port  136  and an audio visual (A/V) port  1138  may also be hidden behind the door. Within one of the hand grips  1028 , a flash  1112  may be disposed. A photographic lens  1106  may be disposed in the other hand grip  1028 . In one embodiment, the lens  1106  may be a high-quality optical zoom lens with motorized zooming capabilities. A shutter release  1112  is provided central to the housing  1002  so that it may be actuated by the index finger of either hand when a user holds the device in an expected manner. While locations of the user interface buttons have been disclosed, other locations are within the scope and contemplation of the invention. By way of example only, the finger pads may be positioned atop the housing adjacent the shutter release to be actuated by e.g., the index finger of each hand. 
     FIG. 12  shows a view of the display of one embodiment of the invention. Image  1200  is the current view as seen by the lens. View  1202  is inset into view  1200  and corresponds to a previously captured image. In one embodiment, it is possible to toggle the view so the current view  1200  may appear inset into a previously captured view. This picture-in-picture functionality permits a user to determine if additional image captures are desirable. 
   A row of icons  1204  is provided as a low profile menu bar along the bottom of the image. The low profile icon bar maximizes image space. Icons  1204  may be activated by moving pointer cursor  1212  to overlap the icon and actuating a pointer button. In one embodiment, placing the cursor over an icon  1204 , e.g., for two seconds, results in a balloon style help manager. In one embodiment, pausing longer on the icon  1204  results in a full screen explanation of the icon&#39;s features. In this manner, a ROM based user manual may be accessed through the device. As previously noted, the device may be provided with either a pointer controller and pointer buttons, absolutely mapped finger pads, or some combination of the foregoing. In either case, the icon  1204 , the virtual keyboard (shown in  FIG. 13 ), and the annotation (shown in  FIG. 13 ) and pointer cursor may be suppressed after a period of time without an input event. 
     FIG. 13  shows a view of the display with a virtual keyboard of one embodiment of the invention. A virtual keyboard  1310  is displayed to permit annotation of photographs or if the device provides web browsing functions other alphanumeric interactions with the display. In one embodiment, annotation  1314  is opened responsive to indication by the user of a desire to annotate the image. This may be done by activating an appropriate icon  1304  or may be automatic in response to detection of typing on a virtual keyboard  1206  or presence of contact on both finger pads. While the virtual keyboard  1306  is shown as a QWERTY keyboard, this need not be the case. Any organization of characters in a keypad is deemed within the scope and contemplation of the invention. 
   Alternatively, in the case of the mapped finger pads, the cursor  1212  and icons  1204  may appear responsive to contact with either single finger pad. The virtual keyboard  1306  may be activated responsive to detection of fingers on both finger pads. In one embodiment, both finger pads  1020 ,  1022  are independent and concurrently operable to activate keys on the virtual keyboard. Images of a right finger  1308  and a left finger  1310  may appear virtually so that a user may manipulate a virtual keyboard  1306  through movement of the virtual fingers  1308  and  1310 . When a virtual finger  1308 ,  1310  is over a virtual key, the key may appear highlighted on the display. As previously noted, actuation of the finger pads may occur when pressed in a z direction. Each finger pad has an independent activator such that pressing the finger pad while a virtual finger is over a key results in a key press event for the highlighted key. 
   In one embodiment, each finger pad has an associated location buffer. The location buffer stores the current value of the location of the finger pad within the orthogonal axes of the region. On an actuation event, the location buffer is checked to confirm the location on actuation. This is expected to reduce error resulting from less than perfectly perpendicular actuation. Thus, in  FIG. 13 , the location buffer would hold a value corresponding to “1” for the right finger pad. If, during the actuation event, the user pressed down and to the left, the key press event would still be an “1,” not a comma. While the virtual finger metaphor has appeal, any pair of independent location indicators may be used. By virtual hunting and pecking, annotations  1214  may readily be made. 
   In one embodiment, while the virtual fingers are active, the pointer cursor  1212  is not. The absolute mapping of the finger pads may take various forms. As previously noted, each region may be mapped to the entire display, or overlapping subsections of the display or partially overlapping subsections of the display. It is also within the scope and contemplation of the invention to change the mapping either automatically or under user control. For example, in one embodiment, the left finger pad may be mapped to the left-hand side of the display when the right finger pad is active and mapped to the entire display when the right finger pad is not active. This permits the pointer cursor  1212  full access to the display while restricting typing activity of the left hand to the left-hand side of the display. 
     FIGS. 14A &amp; 14B  are a block diagram of a hand held device of one embodiment of the invention. Management and control unit (“MCU”) is provided to control and manage subsystems of the device. An ASIC may also be provided to assist in the control of various peripherals. MCU may include a reduced instruction set computing (“RISC”) central processing unit (“CPU”) core which may execute an operating system (“O/S”) such as, Windows CE available from Microsoft Corporation of Redmond, Wash. Other operating systems such as, Linux, Symbian, Palm O/S, VX Works or other Proprietary O/S may be used. In one embodiment, the CPU also executes one or more applications under the control of the O/S. Possible applications include a text editor which may include: word processing, specialized picture and text layout tools, and image-centric document templates. An image capture manager may be provided which may provide screen based controls and display of vital data about the settings, dialog box warnings and the balloon help (described with reference to  FIG. 13  above). A photo editor may also be provided, which provides tools to adjust color of, contrast of, crop, scale, and rotate images captured. An image file manager may also be provided which may provide image history such as date of capture, as well as category notes, edit trail, compression of images, sorting tools, automatic review and timing for action sequences for a series of captured images. A plurality of device drivers may be executed by the CPU core under the control O/S. Such device drivers may include a display driver, CCD lens driver, a storage media driver, audio driver, power manager, virtual keyboard driver, and pointer interface drivers. Other drivers may be used if required to drive additional subsystems and may be executed by the CPU core. In one embodiment, a user manual is retained in non-volatile memory within the device. Software updates are easily done either through the USB port or through one of the media card slots. This provides great flexibility and a robust device adaptable with changes in technology. This also permits different price points depending on the software supplied. 
   It should be noted that features shown or described with reference to one embodiment may be applicable to another embodiment even when not explicitly called out and such is within the scope and contemplation of the invention. In the foregoing specification, the invention has been described with reference to specific embodiments thereof. It will be further evident that various modifications and changes can be made thereto without departing from the broader spirit and scope of the invention as set forth in the appended claims. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.