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This is a divisional, of application Ser. No. 08/159,528 filed Dec. 1, 1993, now U.S. Pat. No. 5,506,011.
BACKGROUND OF INVENTION
The present invention relates in general to packaging prepared from a paperboard laminate. More particularly, the present invention relates to a heat-sealable paperboard laminate, and packages constructed from that laminate, which includes a buried polyvinyl alcohol copolymer (PVOH) barrier material.
Barrier materials are used in paperboard packaging to accomplish several results. First, barrier materials are required to prevent the egress from the package of flavors, aromas and other ingredients of the packaged product. Secondly, barrier materials are also required to prevent the ingress into the package of oxygen, moisture and other contaminants that might degrade the packaged product.
Many attempts have heretofore been made to provide barrier properties to paperboard packaging. For example, low density polyethylene (LDPE) is a well known component of prior art paperboard packaging since it provides good moisture resistance, and, because it is heat sealable, it provides a means for fabricating the packages. Likewise, the presence of a metallic foil as an inner barrier also significantly reduces the transmission of flavors and aromas out of the package and the transmission of oxygen into the package. However, laminates including metallic foil are difficult to recycle and the use of foil significantly increases the cost of the resulting package. Other attempts at providing barrier protection in paperboard packaging have involved the use of polymeric barrier materials such as ethylene vinyl alcohol copolymers (EVOH); polyvinylidene chloride and its copolymers (PVDC); polyacrylonitrile and its copolymers (PAN); polyamides (PA); polyethylene terephthalate (PET); polyvinyl chloride (PVC); and polypropylene (PP). Of these materials, EVOH is the preferred barrier material (see article entitled, "HIGH BARRIER POLYMERS", by A. L. Blackwell, 1986 Coextrusion Seminar, Marriott Hilton Head, Hilton Head, S.C., published by TAPPI Press). In addition polyvinyl alcohol (PVOH) has been suggested in the past as a potential barrier material (see U.S. Pat. Nos. 4,239,826; 4,254,169; 4,407,897; 4,425,410; and 4,464,443). However, the patented uses for PVOH as a barrier material are for film-only packaging. This is partly due to the fact that PVOH is highly sensitive to moisture, but its absence from paperboard packaging is believed to be primarily due to the fact that it is difficult to process.
The barrier properties and particularly the oxygen permeability rate of most polymers is dependent to some degree on the relative humidity to which they are exposed. For example, the oxygen permeability of both EVOH and PVOH is lower under dry conditions than under humid conditions, while the oxygen permeability of amorphous nylon (SELAR PA), is lower under humid conditions than under dry conditions. Because of this sensitivity to moisture, most laminates used for packaging which incorporate a barrier, are usually multi-layered, with the barrier material surrounded by layers designed to keep it isolated from both atmospheric humidity and the moist contents of the packaged products. In the case of refrigerated liquid products stored in paperboard containers, both the inside and outside of the container may be at or near 100% RH. If it is assumed that the entire structure is at equilibrium, it may be concluded that the barrier layer, even though sandwiched between other layers, is also at 100% RH. However, for packaging dry products, and non-refrigerated liquid products, where the moisture conditions are less extreme, the moisture sensitivity of the barrier material may not be of overwhelming concern. Thus, the relatively low oxygen permeability of PVOH, particularly at low RH, makes it an attractive candidate for use as a barrier material in paperboard laminates, particularly for packaging non-refrigerated liquid products and for dry products, despite its processing difficulties.
SUMMARY OF INVENTION
It is an object of the present invention to provide an improved heat-sealable, non-foil paperboard laminate with PVOH as a barrier material, for use in making packaging. In particular, the present invention is useful for packaging dry products, or liquid products that do not require refrigeration.
In one embodiment of the present invention, a PVOH barrier material is applied directly to paperboard. In another embodiment of the invention, the PVOH barrier material may be applied to the paperboard in the form of a coextruded sandwich.
Using VINEX polyvinyl alcohol copolymer resins from Air Products and Chemicals, a layer of PVOH was successfully applied directly to paperboard in the form of an extrusion coating. A good bond was achieved by first applying water to the paperboard surface to pre-treat the surface before extrusion coating. By practicing this method, the PVOH becomes partially dissolved, allowing it to penetrate slightly into the surface of the paperboard, resulting in a strong fiber-tearing bond. This method may be practiced by any suitable coating technique including coextrusion, extrusion coating, or by laminating an already prepared film of PVOH to the wetted surface of the paperboard. Laminates prepared according to this method demonstrated low oxygen permeability particularly under conditions of low relative humidity. At room temperature and under dry conditions (20% RH), the oxygen permeability of a 0.5 mil thick layer of PVOH extrusion coated on paperboard is less than 0.01 cc mil/100 in 2 day ATM, making PVOH a better oxygen barrier than either EVOH or nylon (SELAR PA) under these conditions.
In another embodiment of the present invention, the PVOH barrier material was applied to the paperboard as a coextruded sandwich including low density polyethylene (LDPE), a good moisture barrier which is also heat sealable, and tie layers. This method requires the use of coextrudable layers which have melt temperatures close to the melt temperature of PVOH. Whereas LDPE and the tie layers generally useful with LDPE typically are extruded at temperatures greater than 500° F., PVOH begins to degrade at about 430° F. Therefore, the grades of LDPE useful with PVOH must have a melt temperature of around 400° F. and the tie layers must likewise have melt temperatures lower than conventional tie layers. Coextrusion techniques may also be used to make the products of the first embodiment where the PVOH is in direct contact with the paperboard. For example, a sandwich layer of PVOH/tie layer/LDPE, may be coextruded directly onto a treated paperboard surface, or a sandwich layer comprising tie layer/LDPE may be coextruded onto a PVOH layer which was previously applied to the paperboard. Those skilled in the art will readily foresee other possible combinations within the scope of the present invention.
Accordingly, the present invention may be seen to comprise a substantially oxygen impermeable, leak-free, paperboard laminate incorporating PVOH as its barrier material, container blanks formed from the laminate and containers formed from the blanks. A preferred embodiment of the laminate structure comprises inner and outer layers of a heat sealable polymer such as LDPE, paperboard such as milk carton stock, one or more interior layers of PVOH and appropriate tie layers. The PVOH layer is preferably a VINEX polyvinyl alcohol copolymer resin from Air Products and Chemicals Company, but other PVOH resins could be substituted. The VINEX resins are extrudable grades of polyvinyl alcohol with barrier properties that make them suitable for packaging oxygen sensitive goods and non-food products. VINEX 1003 is insoluble at 100° F., and may be more suitable for liquid packaging than other grades. However, since the VINEX resins are moisture sensitive, it is important that they be protected from moisture. Polymers such as LDPE are suitable for this purpose to ensure that the VINEX resin layer remains relatively dry during use. Meanwhile, the tie layer materials must be suitable for forming strong bonds between PVOH and the other polymers used in the laminate. A specialty grade of LDPE that will process at lower temperature is available from Eastman Chemical Corporation under the designation E6838-065P. Likewise, lower temperature tie layers are available from Quantum Chemical Company (PLEXAR 3342) and from Dupont (BYNEL E-406 or BYNEL E-409).
The package structures formed from the laminates of the present invention exhibit good barrier properties and may be produced using conventional equipment. The packages can be used for a variety of food and non-food packaging applications. Such packages make use of heat seals for forming and closing, and are utilized in the formation of folding boxes, rectangular containers and other shapes. A particular application is in the manufacture of gable top containers.
DESCRIPTION OF DRAWING
FIG. 1 is a cross-sectional elevation of a preferred embodiment of the laminate of the present invention;
FIG. 2 is a cross-sectional elevation of a modification of the laminate structure shown in FIG. 1;
FIG. 3 is a cross-sectional elevation of an alternative embodiment of the laminate of the present invention;
FIG. 4 is a cross-sectional elevation of yet another alternative embodiment of the laminate of the present invention;
FIG. 5 is a block diagram showing typical steps used to make the laminate of FIG. 1;
FIG. 6 is a block diagram showing an alternative method for making the laminate of FIG. 1;
FIG. 7 is a block diagram showing typical steps for making the laminate of FIG. 3;
FIG. 8 is a block diagram showing typical steps for making the laminate of FIG. 4; and
FIG. 9 is a block diagram showing an alternative method for making the laminate of FIG. 4.
DETAILED DESCRIPTION
Referring to FIG. 1, the preferred embodiment of the laminate of the present invention is shown as comprising a paperboard substrate having inner and outer surfaces. On the outer surface of the paperboard there is an outer layer of a heat seal polymer for example LDPE, having a coat weight on the order of abut 6-18 lbs/ream (ream size 3,000 sq. ft.). On the inner surface of the paperboard there is a layer of barrier material for example PVOH, having a coat weight on the order of about 4-6 lbs/ream, and an inner layer of a heat seal polymer having a coat weight on the order of about 6-18 lbs/ream. Depending upon how the laminate is made, there may also be a tie layer between the PVOH barrier layer and the inner heat seal layer. The tie layer would preferably have a coat weight of from about 4-6 lbs/ream.
The preferred method for manufacturing the laminate structure shown in Figure i is illustrated in FIG. 5, and involves flame treating and coating the outer surface of the paperboard substrate with an outer layer of heat seal polymer. The inner surface of the paperboard substrate is then primed with water before the coextrusion PVOH/tie/heat seal polymer is applied to the substrate. In an alternative method as shown in FIG. 6, the PVOH layer is applied to the treated paperboard surface followed by the application of the coextrusion tie/heat seal polymer to finish the inner surface of the substrate. With either method a laminate structure having good barrier properties is achieved. Containers prepared from the laminate material are heat sealable on conventional equipment at conventional temperatures.
Referring to FIG. 2, there is illustrated a modification of the laminate structure shown in FIG. 1 wherein two PVOH layers are applied to a central core of paperboard. For this embodiment, the outside surface of the paperboard substrate is primed with water before a coextrusion of PVOH/tie/heat seal polymer is applied to the outer surface. The substrate is flipped over, and the inner surface of the paperboard substrate is primed with water before an inner coextruded sandwich of PVOH/tie/heat seal polymer is applied to the inner surface. Alternatively, coextrusions of PVOH/tie may be applied to each treated surface of the paperboard substrate before layers of heat seal coating are applied over the coextrusions, or PVOH layers may be applied to the treated paperboard surfaces followed by coextrusions of tie/heat seal coating. The result is a laminate as shown in FIG. 2 comprising from outside to inside, a heat seal layer, tie layer, PVOH barrier layer, paperboard substrate, PVOH barrier layer, tie layer and a heat seal layer. The advantages of this construction is the presence of two PVOH barrier layers and the ability to readily fold the laminate in either direction by applying score lines to either surface of the laminate.
FIG. 3 illustrates an alternative construction according to the present invention wherein the PVOH barrier layer is buried in a symmetrical sandwich which is coextruded onto the paperboard substrate. For this purpose as shown in FIG. 7, the outer surface of the substrate is flame treated to promote adhesion, and an outer layer of a heat seal coating is applied thereto. The web is turned over so the inner surface of the substrate can be flame treated, and a coextrusion comprising a heat seal layer/tie layer/PVOH layer/tie layer/heat seal layer is coextruded onto the treated inner surface of the substrate. This construction provides a laminate that yields good barrier properties using well known manufacturing techniques. The heat sealability of this construction can be improved by applying an additional layer of heat sealable material to the exposed surface of the sandwich layer.
The following embodiments of the present invention involve multiple substrate layers in the barrier laminate. FIG. 4 illustrates a laminate comprising from the outside to the inside, a heat seal layer/substrate/PVOH layer/substrate/heat seal layer. In the preferred form of this embodiment, one substrate layer is a thick sheet of paperboard to provide stiffness, and the other substrate layer is a fairly thin sheet of paper with little or no structural strength. Alternatively, both substrate layers could be paperboard or paper. This structure is preferably manufactured as shown in FIG. 8 by starting with a paperboard substrate and a paper substrate each having heat seal coatings already applied to their outer surfaces. The PVOH layer in this case is used to laminate the two coated substrates together after the exposed surfaces of the paperboard and paper are primed with water. Alternatively the same laminate may be manufactured as shown in FIG. 9 by first coating the outer surface of the paperboard substrate with an outer heat seal layer before laminating the paper substrate to the coated board substrate with the PVOH layer. Finally, the exposed surface of the paper substrate is coated with an inner heat seal layer. In the latter process, the outer surfaces of the paperboard and paper substrates are preferably flame treated to enhance adhesion of the heat seal coating while the inner surfaces are primed with water to achieve good bonding with the PVOH barrier layer. The advantages of a structure according to FIG. 4 are the use of less total plastic material than with coextruded structures, no expensive tie layers and, of course, the absence of a coextrusion process.
The paperboard substrate in the FIG. 4 embodiment is preferably milk carton stock in the basis weight range of about 150-300 lbs/ream (ream size 3000 sq. ft.), preferably 260 lbs/ream for half gallon size gable top cartons. The PVOH layer is a VINEX polyvinyl alcohol copolymer resin having a coat weight of about 4-6 lbs/ream, and the paper layer is preferably a light weight, uncoated paper product having a basis weight on the order of about 40-100 lbs/ream (ream size 3300 sq. ft.). The heat seal layers are preferably LDPE with the outside layer having a thickness in the range of about 6-16 lbs/ream (ream size 3000 sq. ft.), preferably 12 lbs/ream, and the inside layer having a thickness of at least about 10 lbs/ream for good heat sealability.
Although specific coating techniques have been described for preparing the various laminate structures of the present invention, any appropriate technique for applying the layers onto the substrates disclosed may be employed, such as extrusion, coextrusion, extrusion lamination or adhesive lamination of single layer and/or multilayer films. Containers prepared from these structures provide good barrier properties against oxygen transmission and the loss of flavors and aromas, particularly under low humidity conditions, and good barrier properties against the penetration of moisture through the laminate. | Paperboard packaging for non-refrigerated liquid products and for dry products contains a buried polyvinyl alcohol copolymer (PVOH) barrier layer which has a low oxygen permeability particularly at low relative humidity, and outer heat-sealable surfaces which provide good resistance to moisture penetration and a means for fabricating the packaging. | 1 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This Application is the U.S. National Stage of International Application No. PCT/EP2008/051559, filed Feb. 8, 2008, which claims priority to Spanish Application No. P200700359, filed Feb. 9, 2007.
OBJECT OF THE INVENTION
The present invention relates to a large capacity basket for purchasing in self service stores and/or supermarkets, of the type of those incorporating rolling means at their base and a drive handle which allows the user to move such baskets in a comfortable manner.
More specifically, the object of the present invention is a basket the structure of which allows transporting a large number of items without this damaging its structure, therefore increasing its durability and reliability.
BACKGROUND OF THE INVENTION
There are different types of baskets on the market intended to be used in supermarkets or self service stores as means so that the clients transport the goods to the checkout counters in which payment is made.
These baskets are presented as an alternative to typical metal carts, which occasionally are not suitable, either because of the number of items which are to be purchased or because the characteristics of the establishment make the circulation of said carts impossible.
Thus, the baskets normally used generally consist of stackable resistant plastic containers which are provided with one or several handles allowing the user to transport them throughout the premises and introduce the items therein.
Finally baskets have appeared which, being equally stackable, further have wheels and a drive handle which allow moving such baskets easily, moving them over the floor of the establishment.
However, as a result of the appearance of the latter baskets and due to their easy transport as a result of the wheels, it is increasingly common for the users to demand them with larger capacity and therefore that they are used to transport a large number of goods, which has certain drawbacks.
These drawbacks, of a structural and/or strength character, appear due to the fact that said baskets are forced to carry out greater efforts and to support larger stresses often causing them to break.
This problem is especially intensified in those baskets which are moved in an inclined manner with regard to the floor, moving on the rolling means forming the pivot axis, and in which its drive handle is located on the same plane of the face on which the items are supported, this being the load plane.
More specifically, the baskets of this type are basically subjected to two types of stresses due to the load that they house in an operative situation. On one hand, the tensile stresses caused by dragging it, and on the other hand the bending stresses caused by the weight of the goods housed therein on the load plane, i.e. on the face on which said goods are supported.
Furthermore, these tensile and bending stresses not only damage the actual structure of the basket, but also the drive handle, and more especially in the case pointed out in which said handle is located on the load application plane, i.e. when the basket is of the type of those that are moved in an inclined manner with regard to the floor by means of wheels or the like.
These stresses thus cause a decrease in the useful life of the baskets, which as is obvious is detrimental to the quality of the product and therefore its profitability.
DESCRIPTION OF THE INVENTION
The shopping basket proposed by the present invention efficiently solves the previously mentioned drawbacks, because even though it has a size which allows carrying a large number of items, it has structural features providing it with the necessary tensile strength, which positively affects its durability, and in addition its profitability, all this without relinquishing its easy transport or the essential requirement of stackability.
To that end the basket of the invention comprises a series of features which on one hand provide it with greater structural strength and on the other hand allow reducing the stress caused by the forces involved as a result of the breakdown thereof.
More specifically, for achieving said objectives the basket of the invention is structured from a basket of the type of those that are moved in an inclined manner with regard to the floor as a result of rolling means forming the pivot axis of said basket, but in which the drive handle is located on a plane different from the load application plane.
Thus, for the specific case in which the drive handle is located on a plane different from the load application plane but parallel thereto and more specifically on a parallel plane moved towards the inside of the basket, an improvement of the modulus of strength of the handle is obtained due to the fact that the side branches of said handle and the points of the body of the basket which are furthest from said plane is less.
In other words, the modulus of strength can be defined as:
W=I/d
wherein I is the moment of inertia of the section of the handle with regard to the bending axis and d the distance to the barycenter.
Therefore, by decreasing the distance d of the handle to the barycenter or center of gravity, the modulus of strength, or in other words, the strength of the assembly is increased.
In addition, for the case in which the drive handle is located on a plane different from the load application plane and inclined with regard thereto, what is achieved is that the forces generated by the load, causing the bending, are broken down into two components, only one of which generates bending since it is orthogonal to the plane of the handle, said component being in any case less than the force that there would be if the handle was located on a plane coinciding with the load plane defined by the face of the basket on which the items are supported upon inclining said basket for its transport.
In other words, Q being the load, it will be broken down into:
{right arrow over (Q)}={right arrow over (qx)}+{right arrow over (qy)}
wherein qx does not generate a bending moment as it is aligned with the plane of the handle, therefore for tensions generated by bending moments, it can be assumed that the load will be =qy
wherein qy=Q cos α,
α being the inclination angle between the plane of the handle and the load plane; from which it is deduced that said component qy will always be less than Q.
However, for the case in which the plane of the handle and the load plane were coincident and therefore a α=0, it can be stated that cos α=cos 0°=1, therefore qy=Q, i.e. the entire load Q would generate a bending moment.
In addition, for improving the strength of the basket even more, such basket can have corners reinforced by means of folds or bends carried out therein.
These bends provide the basket with a greater structural rigidity and strength since on one hand it involves an extra contribution of material to the bending plane in those baskets which are moved in an inclined manner, and therefore an improvement of the modulus of strength.
On the other hand said bends allow the distribution of stresses generated by the load on several orthogonal planes, which favors the distribution of stresses.
DESCRIPTION OF THE DRAWINGS
To complement the description being made and for the purpose of aiding to better understand the features of the invention according to a preferred practical embodiment thereof, a set of drawings is attached as an integral part of said specification, in which the following has been shown with an illustrative and non-limiting character:
FIG. 1 shows an elevational view of a possible embodiment of the invention in which the drive handle is located on an oblique plane with regard to the load plane.
FIG. 2 shows an elevational view of another possible embodiment of the invention in which the drive handle is located on a plane parallel to the load plane.
FIG. 3 shows a plan view and another perspective sectioned view of a possible embodiment of the basket of the invention in which the bends forming the reinforcement of one of the corners can be observed.
FIG. 4 shows a perspective view of a preferred embodiment of the basket of the invention with the drive handle in an operative position.
FIG. 5 shows two elevational views, one of the preferred embodiment of the previous figure and another of the prior state of the art, both in a horizontal position on the face incorporating the drive handle.
FIG. 6 shows a perspective view and an elevational view of several baskets according to the present invention in a stacking position.
PREFERRED EMBODIMENT OF THE INVENTION
In view of the figures indicated, it can be observed how the stackable basket of the invention is basically structured from a body ( 1 ) with a prismatic shape or the like, the edges of which are generally rounded and having a series of cavities ( 2 ).
The basket of the invention likewise has a drive handle ( 4 ) that is extractible, telescopic or the like, and rolling means ( 5 ), such as wheels for example, such that it is inclined with regard to the floor when it is moved as a result of said rolling means ( 5 ), which form the pivot axis of said basket.
According to a possible embodiment of the invention, and as can be seen in FIG. 2 , the drive handle ( 4 ) is located on a plane different from the load application plane, i.e. on a plane different from the plane defining the face ( 11 ) on which the items are supported when the basket is moved in an inclined manner. More specifically, the drive handle ( 4 ) is located on a plane parallel to the load plane and moved towards the inside of the basket, an improvement of the modulus of strength of said handle ( 4 ) thus being obtained.
In addition, according to another possible embodiment of the invention, and as can be seen in FIG. 1 , the drive handle ( 4 ) is located on a plane that is also different from the load application plane, but also inclined with regard thereto, whereby achieving that the forces generated by the load causing the bending are separated into components, the result of which is less than there would be if the handle was located on a plane coinciding with the load plane defined by the face ( 11 ) of the basket on which the items are supported upon inclining said basket for carrying them, as can be observed in FIG. 5 , in which the distribution of said forces on a basket from the prior state of the art and in another one according to this embodiment has been depicted.
In addition, and according to another possible embodiment, the basket of the invention can incorporate corners reinforced by means of bends ( 3 ), as can be seen in the figures, located at least in the corners of the face defining the load plane.
Thus, for the case of the basket the drive handle ( 4 ) of which is located on a plane parallel to the load plane and moved towards the inside of the basket, the bends ( 3 ) will have a shape such that they define a plane ( 6 ) (not depicted) parallel to the plane of the handle such that the side branches ( 7 ) of said handle ( 4 ) slide on said plane ( 6 ) with the aid of guide means.
In addition, for the case of the basket the drive handle ( 4 ) of which is located on a plane inclined with regard to the load plane, the bends ( 3 ) will have a shape such that they define a plane ( 6 ) inclined coinciding with the plane of the handle such that the side branches ( 7 ) of said handle ( 4 ) slide on said plane ( 6 ) with the aid of guide means, as can be seen in FIGS. 3 and 4 .
According to a possible preferred embodiment of the invention, said guide means for guiding the side branches ( 7 ) of the handle ( 4 ) through the bends ( 3 ) will be formed by holes ( 8 ) through which said side branches ( 7 ) slide, said holes ( 8 ) being able to be inclined or not inclined according to each case.
Furthermore, as an element to improve said guiding along the entire run of the handle ( 4 ), this handle will be able to have, on at least one of the side branches ( 7 ) and preferably at its lower end, an element ( 9 ) having a protuberance which runs through a guide channel located for this purpose in the handle sliding area, either the actual wall of the basket or the bend ( 3 ), such that on one hand it guides the movement of said handle ( 4 ) and on the other hand said protuberance prevents the accidental extraction of the side branches ( 7 ) of said handle ( 4 ) both from the guide channel and from the corresponding holes ( 8 ).
The basket of the invention could also be reversibly stacked by simply adding the mentioned bends ( 3 ) in the symmetrical areas, i.e. adding them not only in the corners of the basket formed by the face defining the load plane but also in the rest, as can bee seen in FIG. 6 , thus facilitating its collection and storage for the user.
Also according to another possible embodiment of the invention, the basket of the invention could have orifices ( 10 ) made in one or several of the side faces which by way of a handgrip would allow the user to carry the baskets without needing to use the drive handle ( 4 ), or for example in the event that a set of stackable baskets are to be moved.
Finally, for facilitating the introduction and recovery of the goods for the user, the face of the basket opposite that forming the load plane will be shorter than the rest, thus defining an opening as can be seen in FIGS. 4 , 5 and 6 . | The invention relates to a shopping basket in self service stores and/or supermarkets, of the type of those which can be stacked and incorporate rolling means ( 5 ) at their base and a drive handle ( 4 ) for transporting them in an inclined manner on the floor in which said drive handle ( 4 ) is located on a plane different from the load application plane, and further having its corners reinforced by means of bends ( 3 ) defining a plane ( 6 ) on which the side branches ( 7 ) of said handle ( 4 ) slide with the aid of guide means. | 1 |
FIELD OF THE INVENTION
[0001] The present invention relates to a surface light emitting apparatus and a method of light emission for the same, and more particularly to a surface light emitting apparatus using a hollow multilayer structure and a method of light emission for the same.
BACKGROUND OF THE INVENTION
[0002] A surface light emitting apparatus used as a backlight for a liquid crystal display or the like, achieves surface illumination by causing light from a line light source such as a cold-cathode tube to spread evenly by using a flat light-conducting plate (refer, for example, to patent document 1), to obtain a white light output of uniform brightness across the display's surface area by using a light-conducting plate and a diffusing plate or sheet in order to illuminate the liquid crystal display. A color display can be achieved by combining such a surface light emitting apparatus with a liquid crystal unit constructed from a number of layers such as liquid crystal, color filter, and black matrix layers, but the structure as a whole becomes complex and costly.
[0003] It is also known to arrange a plurality of relatively inexpensive LEDs at equally spaced intervals on a substrate and use the LED array as a surface illumination apparatus for directly illuminating a billboard or the like from the back side thereof. However, with such a surface illumination apparatus, it has been difficult to produce a clearly defined pattern on the illuminated surface.
[0004] Further, a surface light source is known that is constructed by arranging side by side a plurality of light conductive transparent rods each being circular in cross section and having LEDs mounted at both ends thereof (refer, for example, to patent document 2). However, even if a plurality of such circular rods are arranged close to each other, dark areas occur between the transparent rods, and it has not been possible to construct a surface light emitting apparatus that can produce patterns having clearly defined boundaries.
[0005] On the other hand, it is known to provide a hollow structural plate made of a synthetic resin and used as a replacement for corrugated cardboard made of paper (refer, for example, to patent document 3). However, it is not known to use such a hollow structural plate for the construction of a surface light emitting apparatus for illuminating a display or the interior of a building or other articles such as furniture.
[0006] Patent document 1: Japanese Unexamined Patent Publication No. H11-237629
[0007] Patent document 2: Japanese Unexamined Patent Publication No. 2004-39482
[0008] Patent document 3: Japanese Unexamined Patent Publication No. H08-72137
SUMMARY OF THE INVENTION
[0009] Accordingly, it is an object of the present invention to provide a surface light emitting apparatus using a hollow multilayer structure, and a method of light emission for the same.
[0010] It is another object of the present invention to provide a thin, low-power consumption, light-weight, and inexpensive surface light emitting apparatus using a hollow multilayer structure in combination with LEDs, and a method of light emission for the same.
[0011] To solve the above problem, a surface light emitting apparatus according to the present invention includes a hollow multilayer structure formed from a plurality of hollow cells, a light source for emitting light into the hollow multilayer structure through an end face thereof containing a cell opening, and light deflecting means for causing the light introduced through the cell opening-containing end face of the hollow multilayer structure to emerge from a surface of the hollow multilayer structure.
[0012] Preferably, in the surface light emitting apparatus according to present invention, the light deflecting means is a random projection/depression pattern, a dot pattern, or a V-shaped or U-shaped groove formed on the surface of the hollow multilayer structure.
[0013] Preferably, in the surface light emitting apparatus according to present invention, the light deflecting means is a diffusing material added in the hollow multilayer structure.
[0014] Preferably, in the surface light emitting apparatus according to present invention, the light deflecting means is a light conducting member inserted in each of the hollow cells, and preferably, the light conducting member is formed at its surface with a random projection/depression pattern, a dot pattern, or a V-shaped or U-shaped groove, or a diffusing material is added in the light conducting member.
[0015] Preferably, in the surface light emitting apparatus according to present invention, the light deflecting means is a light diffusing material inserted in each of the hollow cells.
[0016] Preferably, in the surface light emitting apparatus according to present invention, the light source is constructed from a plurality of LEDs, and preferably, the plurality of LEDs are respectively mounted in the plurality of hollow cells.
[0017] Preferably, in the surface light emitting apparatus according to present invention, the plurality of LEDs are mounted one for one in the plurality of hollow cells at least at one of two cell opening-containing end faces of the hollow multilayer structure.
[0018] To solve the above problem, a method of light emission for a surface light emitting apparatus according to present invention includes the steps of arranging a plurality of light sources for each of a plurality of hollow cells each separated by a transparent rib, introducing differently colored lights respectively emitted from the plurality of light sources into a corresponding one of the plurality of hollow cells, and emerging colored light produced by mixing the differently colored lights emitted from the plurality of light sources from a surface of a hollow multilayer structure.
[0019] To solve the above problem, an alternative method of light emission for a surface light emitting apparatus according to present invention includes the steps of arranging a plurality of light sources for each of a plurality of hollow cells each separated by an opaque rib, introducing differently colored lights respectively emitted from the plurality of light sources into a corresponding one of the plurality of hollow cells, and emerging the differently colored lights emitted from the plurality of light sources and prevented from mixing with each other by the opaque rib from a surface of a hollow multilayer structure.
[0020] Preferably, in the method of light emission for the surface light emitting apparatus according to present invention, the plurality of light sources each include a red LED element, a green LED element, and a blue LED element.
[0021] Preferably, in the method of light emission for the surface light emitting apparatus according to present invention, each of the plurality of light sources is a single red LED, a single green LED, a single blue LED, or a single white LED.
[0022] Preferably, the method of light emission for the surface light emitting apparatus according to present invention further comprises the step of causing the colors of the colored lights being emitted from the plurality of light sources to change as time elapses.
[0023] According to the present invention, since surface illumination is accomplished by introducing light through the cell opening-containing end face of the hollow multilayer structure, it becomes possible to provide a thin, low-power consumption, light-weight, and inexpensive surface light emitting apparatus.
[0024] Furthermore, according to the present invention, since the light from the light source is emitted indirectly through the cell opening-containing end face of the hollow multilayer structure, it becomes possible to provide a surface light emitting apparatus that can create an atmosphere that gives a psychological effect pleasing and appealing to human senses.
[0025] Moreover, according to the present invention, since the differently colored lights introduced into the plurality of hollow cells separated by transparent ribs can be mixed together, and the resulting colored light can be emitted from the surface of the hollow multilayer structure, it is possible to produce a color illumination that has not been possible with the prior art.
[0026] Further, according to the present invention, since the differently colored lights introduced into the plurality of hollow cells separated by opaque ribs can be emitted from the surface of the hollow multilayer structure without mixing them together, it is possible to produce illumination of a color that has not been possible with the prior art.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a front view of a wall-hanging panel type surface light emitting apparatus according to the present invention as viewed facing the light emitting side thereof.
[0028] FIG. 2 is a cross-sectional view of the wall-hanging panel type surface light emitting apparatus shown in FIG. 1 .
[0029] FIG. 3 is a diagram schematically showing the configuration of a light source used in the wall-hanging panel type surface light emitting apparatus.
[0030] FIG. 4 is a perspective view of a hollow multilayer structure.
[0031] FIG. 5 is a diagram showing the direction along which grooves are formed in the hollow multilayer structure.
[0032] FIG. 6 is a cross-sectional view of another wall-hanging panel type surface light emitting apparatus.
[0033] FIG. 7 is a diagram schematically showing the structure of a light conducting member.
[0034] FIG. 8 is a cross-sectional view of still another wall-hanging panel type surface light emitting apparatus.
[0035] FIG. 9 is a diagram showing one example illustrating how the hollow multilayer structure is illuminated with colored lights emitted from LEDs.
[0036] FIG. 10 is a perspective view of an alternative hollow multilayer structure.
[0037] FIG. 11 is a diagram showing another example illustrating how the hollow multilayer structure is illuminated with colored lights emitted from LEDs.
[0038] FIG. 12 is a front view of a floor-standing panel type surface light emitting apparatus according to the present invention as viewed facing the light emitting side thereof.
[0039] FIG. 13 is a cross-sectional view of a portion of the floor-standing panel type surface light emitting apparatus shown in FIG. 12 .
[0040] FIG. 14 is a perspective view of a double-sided illumination panel type surface light emitting apparatus according to the present invention.
[0041] FIG. 15 is a cross-sectional view of the double-sided illumination panel type surface light emitting apparatus shown in FIG. 14 .
[0042] FIG. 16 is a perspective view of a hollow multilayer structure used in the double-sided illumination panel type surface light emitting apparatus shown in FIG. 14 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0043] A surface light emitting apparatus according to the present invention will be described below with reference to the drawings. However, it should, be understood that the present invention is not limited to the embodiments shown in the drawings or illustrated herein.
[0044] FIG. 1 is a front view of a wall-hanging panel type surface light emitting apparatus 1 as viewed facing the light emitting side thereof when the surface light emitting apparatus according to the present invention is constructed as a wall-hanging panel. FIG. 2 is a cross-sectional view taken along line AA′ in FIG. 1 .
[0045] As shown in FIGS. 1 and 2 , the wall-hanging panel type surface light emitting apparatus 1 comprises a hollow multilayer structure 10 , a frame member 20 having an opening 21 , an LED circuit substrate 30 , and LEDs 31 . A first diffusing sheet 40 , a lens sheet 41 , and a second diffusing sheet 42 are formed one on top of another in this order on the light emitting surface side of the hollow multilayer structure 10 (i.e., the same side as the opening 21 of the frame 20 ). A reflective sheet 43 is provided on the back surface side of the hollow multilayer structure 10 .
[0046] FIG. 3 is a diagram schematically showing the LED circuit substrate 30 and the light source constructed from the LEDs 31 . The circuitry mounted thereon is not shown here.
[0047] The plurality of LEDs 31 are arranged at equally spaced intervals on the LED circuit substrate 30 . Each LED is a three-in-one LED comprising a red LED element 32 , a green LED element 33 , and a blue LED element 34 in a single package, and can emit light of a designated one of a plurality of colors by mixing colored lights from the respective LED element according to an input signal. Each LED 31 illuminates in the designated color by a current supplied from a power supply 51 in accordance with the control timing and the color designated by a control unit 50 . The use of a sensor 52 will be described later, but the provision thereof is not essential. Further, each LED 31 may be constructed from a single-color LED, for example, a red LED, a green LED, a blue LED, or a white LED. When using single-color LEDs, it is preferable to arrange a plurality of LEDs so as to correspond with one hollow cell, because a variety of colors can then be produced. For the LEDs, not only the above-described chip type but other types of LED such as an oval type or a shell type can also be used.
[0048] FIG. 4 is a perspective view showing the hollow multilayer structure 10 .
[0049] The hollow multilayer structure 10 is constructed by integrally forming a plurality of hollow cells 11 one adjacent to another along the longitudinal direction thereof. More specifically, the structure comprises a top plate 12 , a bottom plate 13 , and a plurality of ribs 14 . The term multilayer in the hollow multilayer structure 10 refers to at least two layers consisting of the top plate 12 as the front layer and the bottom plate 13 as the back layer. Each cell is a space enclosed by the top plate, bottom plate, and ribs and having openings at both ends.
[0050] In the present embodiment, the hollow cells 11 each measure 750 mm in length a, 6 mm in horizontal width b, and 6 mm in vertical width (height) c, and the top plate 12 , the bottom plate 13 , and the ribs 14 are all formed from a 0.33-mm thick transparent polycarbonate resin (hereinafter called the PC resin). The above hollow cell size is only one example, and other dimensions may be employed. Further, the hollow multilayer structure may be formed from a PMMA resin, an MS resin, a polyester resin such as PET, a PSt resin, a COP resin, a COC resin, an olefin resin such as a PP resin or a PE resin, a PVC resin, an ionomer resin, glass, etc.
[0051] As shown in FIG. 4 , each LED 31 has a shape insertable in the corresponding hollow cell 11 , and as shown in FIG. 2 , when fabricating the wall-hanging panel type surface light emitting apparatus 1 , the LEDs 31 are mounted so as to be inserted into the openings of the respective hollow cells 11 . In view of this, it is preferable to determine the dimensions b×c of each hollow cell 11 so that the LED 31 used as the light source fits into it.
[0052] Preferably, the LEDs 31 are arranged with their light emission centers aligned parallel to the longitudinal direction of the respective hollow cells 11 , and more preferably, the LEDs 31 are arranged so that their light emission centers coincide with the longitudinal center-lines of the respective hollow cells 11 . With the LEDs inserted into the openings of the respective hollow cells 11 , the structure offers several advantages, such as preventing the LEDs from being misaligned relative to the multilayer structure, enhancing the light emission efficiency by preventing the light from each LED from spreading out, and enhancing the fabrication work efficiency by integrating the LEDs with the hollow cells.
[0053] In the above example, one LED is provided for each hollow cell, but LEDs need not necessarily be provided for all the cells. For example, the LEDs may be provided one for every predetermined number of cells, for example, one for every two cells. Alternatively, the hollow multilayer structure may be constructed by arranging large hollow cells alternately with small hollow cells having a smaller horizontal width dimension (b) or vertical width dimension (c), and LEDs may be provided only for the larger hollow cells and no LEDs for the smaller hollow cells. Even when the LEDs are provided only for the larger hollow cells in such a hollow multilayer structure, the structure functions as the surface light emitting apparatus because the surfaces of the smaller cells are illuminated with colored lights diffusing from the larger cells into the smaller cells.
[0054] Next, a description will be given of light deflecting means by which light entering each hollow cell 11 through a cell opening from a side face of the hollow multilayer structure 10 is caused to emerge from the light emitting surface of the hollow multilayer structure 10 .
[0055] As shown in FIG. 2 , much of the light 100 emitted from the LED 31 propagates through the hollow cell 11 along its longitudinal direction, while undergoing reflections therein, toward the other LED 31 mounted at the opposite end (for example, see light 101 ). In this situation, it cannot be expected that a sufficient amount of light will emerge from the light emitting surface of the hollow multilayer structure 10 . To address this, in the surface light emitting apparatus according to the present invention, a plurality of V-shaped grooves (each measuring 3 μm in depth and 20 μm in width) are formed extending along direction X orthogonal to the longitudinal direction of the hollow cell over the entire light emitting surface (of the top plate 12 ) of the hollow multilayer structure 10 . The V-shaped grooves are formed by continuously varying the interval, i.e., at 5-mm interval in the portion near the LED 31 and at 50-μm interval in the center portion of the hollow cell 11 . When the light 100 emitted from the LED 31 and propagated through the hollow cell 11 strikes the top plate 12 and is incident on one such V-shaped groove 102 , the incident light is directed toward the light emitting surface of the hollow multilayer structure 10 . In this way, the light emitted from each LED 31 is caused to emerge from the light emitting surface of the hollow multilayer structure 10 by the V-shaped grooves formed over the entire surface of the hollow multilayer structure 10 . In this case, the viewer views the surface illuminated with colored light. The light emitted from each LED 31 mostly emerges from the entire light emitting surface that extends along the longitudinal direction of the hollow cell into which the LED 31 is fitted. However, if the ribs 14 in the hollow multilayer structure 10 are transparent, the light gradually diffuses into the light emitting surfaces of the adjacent hollow cells, producing naturally colored lights near each rib 14 due to additive color mixing and thus generally resulting in the formation of stripe patterns (see FIG. 9 ). On the other hand, if the ribs 14 are opaque, the light does not diffuse into the adjacent hollow cells, and as a result, clearly defined stripe patterns are formed (see FIG. 11 ).
[0056] In the example of FIG. 2 , the LED 31 is provided at each end of the hollow cell, but the LED 31 may be provided only at one end. In that case, it is preferable to provide a reflective sheet at the end face where the LED 31 is not provided.
[0057] The first and second diffusing sheets 40 and 42 for evenly spreading the light emerging from the light emitting surface and the lens sheet 41 by which the scattered light from the hollow multilayer structure 10 is deflected in a direction perpendicular to the light emitting surface are provided on the light emitting side of the hollow multilayer structure 10 . In the example of FIG. 2 , only one lens sheet is provided, but two lens sheets may be provided for X and Y directions respectively. Further, considering the fact that the light exiting each V-shaped groove is not always directed toward the light emitting side of the hollow multilayer structure 10 , the reflective sheet 43 is provided on the back surface side of the hollow multilayer structure 10 in order to make effective use of the light and to increase the amount of light that emerges from the light emitting surface of the hollow multilayer structure 10 . Here, if the reflective sheet is not used, the lightness and saturation of the illuminated surface can be adjusted lower, making it easier to produce color illumination having darker color shades. In that case, color illumination having transparency and depth like those of a crystal can also be produced by utilizing the phenomenon that delicate shades are formed within the hollow cells.
[0058] Preferably, the first and second diffusing sheets 40 and 42 are each formed from a transparent resin such as a PC resin or a PET resin. For the lens sheet 41 , it is preferable to use a BEF sheet or a DBEF sheet (both manufactured by 3M). For the reflective sheet 43 , it is preferable from the standpoint of increasing the amount of emergent light to use a sheet or structure whose reflectance to visible light is 50% or higher (more preferably, 80% or higher), such as a sheet formed from a PET film containing titanium oxide or the like, a sheet formed by depositing aluminum, silver, or the like on a PET film, or a low foamed structure formed from a PC resin, a PET resin, or the like.
[0059] The first and second diffusing sheets 40 and 42 , the lens sheet 41 , and the reflective sheet 43 need not necessarily be provided, but should be provided as needed according to the application.
[0060] In the above example, the plurality of V-shaped grooves as one example of the light deflecting means are formed extending along direction X orthogonal to the longitudinal direction of the hollow cell over the entire light emitting surface of the hollow multilayer structure 10 . However, the direction along which each V-shaped groove is formed is not necessarily limited to the direction X orthogonal to the longitudinal direction of the hollow cell, but each groove may be formed, for example, along direction Y parallel to the longitudinal direction of the hollow cell, or along a direction, such as Z direction, tilted at an angle of 35 to 55 degrees, preferably 45 degrees, relative to the longitudinal direction of the hollow cell (see FIG. 5 ). Further, each V-shaped groove need not necessarily be formed continuously, but may be formed in a discontinuous manner.
[0061] Further, in the above example, the V-shaped grooves 102 , each measuring 3 μm in depth and 20 μm in width, are formed at an interval varying from 5 mm to 50 μm, but the dimensions and interval of the V-shaped grooves are not limited to these specific values, and other suitable values can be employed as needed. Among them, the depth of each V-shaped groove is preferably in the range of 3 to 6 μm, and the width is preferably in the range of 20 to 40 μm. Further, the V-shaped grooves may be formed at equal interval over the entire longitudinal length of the hollow cell 11 .
[0062] As the light deflecting means, use may be made of other patterns than the V-shaped grooves described above, such as U-shaped grooves, a dot pattern (a pattern of dot-like microscopic projections and depressions) engraved or printed by laser, an array of inverted square pyramid shaped depressions, random projections and depressions formed by chemical, plasma, electron beam, or other etching techniques, inverted V-shaped projections, and inverted U-shaped projections. Further, the V-shaped grooves, the U-shaped grooves, the dot pattern, the array of inverted square pyramid shaped depressions, the random projections and depressions formed by etching, the inverted V-shaped projections, the inverted U-shaped projections, etc. described above may be formed not only on the front surface of the top plate 12 , that is, the light emitting surface of the hollow multilayer structure 10 , but also on the back surface of the top plate 12 or the front or back surface of the bottom plate 13 disposed on the side opposite from the light emitting surface side, or on more than one of these surfaces.
[0063] Further, the light deflecting means may be provided in the form of a random projection/depression pattern formed on the front surface of the top plate 12 that forms the light emitting surface of the hollow multilayer structure 10 . The random projection/depression pattern can be formed by roughening the surface of the hollow multilayer structure by sandblasting, or by engraving the pattern in the surface of the top plate 12 by a heated press plate having such a projection/depression pattern. In this case, the Rz value (JIS 2001-B0601) of the projection/depression pattern is preferably not smaller than 0.04 μm but not larger than two-thirds of the thickness of the top plate 12 of the hollow multilayer structure. If the roughness is smaller than 0.04 μm, the colored light from the light source cannot be sufficiently scattered, nor can the light be caused to emerge effectively. However, if it is larger than two-thirds of the thickness of the top plate 12 of the hollow multilayer structure, the hollow multilayer structure cannot retain sufficient strength. The random projection/depression pattern may be formed on the back surface of the top plate 12 of the hollow multilayer structure 10 or the front or back surface of the bottom plate 13 disposed on the side opposite from the light emitting surface side, or on more than one of these surfaces.
[0064] Alternatively, the light deflecting means may be provided in the form of (optically transmissive) projections formed by spraying a solution containing a thermosetting or thermoplastic resin, rubber, or a gel-like material over the front surface of the top plate 12 that forms the light emitting surface of the hollow multilayer structure 10 , and thereafter solidifying the solution by volatizing the solvent in the solution or by thermally curing the solution.
[0065] Further, the light deflecting means may be provided in the form of air bubbles formed in the hollow multilayer structure by such means as laser radiation or heating.
[0066] Alternatively, the light deflecting means may be formed by adding a diffusing material in the hollow multilayer structure 10 . As the diffusing material to be added here, use can be made of inorganic particles of glass, silica, mica, synthetic mica, calcium carbonate, barium sulfate, talc, montmorillonite, kaolin clay, bentonite, hectorite, etc., metal oxide particles of titanium oxide, zinc oxide, tin oxide, alumina, etc., or polymer particles of acrylic beads, styrene beads, benzoguanamine, silicone, etc. For example, when the hollow multilayer structure 10 is formed from a PC resin, haze is 67.3% when 0.05 parts of silicone with an average particle size of 2 μm are added as the diffusing material per 100 parts of the PC resin, 83% when 0.1 parts of such silicone are added, and 93% when 0.5 parts of such silicone are added. The haze when the diffusing material is added is preferably not lower than 10% but not greater than 99%. If the haze is lower than 10%, a sufficient light scattering effect cannot be obtained, and if it is greater than 99%, a sufficient amount of emergent light cannot be obtained.
[0067] The light deflecting means may also be provided in the form of a light conducting member 200 placed inside each hollow cell 11 in the hollow multilayer structure 10 .
[0068] FIG. 6 shows one example of a panel type surface light emitting apparatus 2 that uses such a light conducting member 200 .
[0069] The panel type surface light emitting apparatus 2 is similar in structure to the foregoing wall-hanging panel type surface light emitting apparatus 1 , except that the light conducting member 200 is inserted in each hollow cell 11 in the hollow multilayer structure 10 and that no V-shaped grooves are formed on the top panel 12 on the light emitting side of the hollow multilayer structure 10 , and therefore, only the differences in structure will be described below.
[0070] In the panel type surface light emitting apparatus 2 shown in FIG. 6 , much of the light 110 emitted from the LED 31 propagates through the light conducting member 200 , while undergoing reflections therein, toward the other LED 31 mounted at the opposite end (for example, see light 111 ). In the illustrated example, a plurality of V-shaped grooves (each measuring 3 μm in depth and 20 μm in width) are formed extending along direction X orthogonal to the longitudinal direction of the light conducting member over the entire light emitting surface of the light conducting member 200 (in FIG. 6 , the surface on the same side as the opening 21 of the frame member 20 ). The V-shaped grooves are formed by continuously varying the interval, i.e., at 5-mm interval in the portion near the LED 31 and at 50-μm interval in the center portion of the hollow cell 11 . When the light 110 emitted from the LED 31 is incident on one such V-shaped groove 112 , the incident light is directed toward the light emitting surface of the light conducting member 200 . In this way, the light emitted from each LED 31 is caused to emerge from the entire light emitting surface of the hollow multilayer structure 10 by the V-shaped grooves formed on the light emitting surface of the light conducting member 200 . The light emitted from each LED 31 mostly emerges from the entire light emitting surface of the light conducting member 200 that extends along the longitudinal direction of the light conducting member into which the LED 31 is fitted; here, if the ribs 14 in the hollow multilayer structure 10 are transparent, the light gradually diffuses into the light emitting surfaces of the adjacent hollow cells, producing naturally colored lights near each rib 14 due to additive color mixing and thus generally resulting in the formation of stripe patterns. On the other hand, if the ribs 14 are opaque, the light does not diffuse into the adjacent hollow cells, and as a result, clearly defined stripe patterns are formed.
[0071] The first and second diffusing sheets 40 and 42 for evenly spreading the light emerging from the light emitting surface and the lens sheet 41 by which the scattered light from the hollow multilayer structure 10 is deflected in a direction perpendicular to the light emitting surface are provided on the light emitting side of the hollow multilayer structure 10 . Further, considering the fact that the light reflected by each V-shaped groove is not always directed toward the light emitting side of the hollow multilayer structure, the reflective sheet 43 is provided on the back surface side of the hollow multilayer structure 10 in order to make effective use of the light and to increase the amount of light that emerges from the light emitting surface of the hollow multilayer structure 10 . Here, if the reflective sheet is not used, the lightness and saturation can be adjusted lower, making it easier to produce color illumination having darker color shades. In that case, color illumination having transparency and depth like those of a crystal can also be produced by utilizing the phenomenon that delicate shades are formed within the hollow cells.
[0072] FIG. 7 shows one example of the light conducting member 200 used in the panel type surface light emitting apparatus 2 shown in FIG. 6 .
[0073] As shown in FIG. 7 , the light conducting member 200 is formed from an MMA (methyl methacrylate) resin measuring 740 mm in length a, 5 mm in horizontal width b, and 5 mm in vertical width (height) c so that it can be inserted in the hollow cell 11 . Like the hollow multilayer structure 10 , the light conducting member 200 may also be formed from a PMMA resin, an MS resin, a PC resin, a polyester resin such as PET, a PSt resin, a COP resin, a COC resin, an olefin resin such as a PP resin or a PE resin, a PVC resin, an ionomer resin, glass, etc.
[0074] In the above example, the V-shaped grooves are formed extending along direction X orthogonal to the longitudinal direction of the light conducting member 200 over the entire surface thereof on the light emitting side of the hollow multilayer structure 10 ; however, the direction along which each V-shaped groove is formed is not necessarily limited to the direction X orthogonal to the longitudinal direction of the light conducting member 200 , but each groove may be formed, for example, along direction Y parallel to the longitudinal direction of the light conducting member 200 , or along a direction, such as Z direction, tilted at an angle of 35 to 55 degrees, preferably 45 degrees, relative to the longitudinal direction of the light conducting member 200 . Further, each V-shaped groove need not necessarily be formed continuously, but may be formed in a discontinuous manner. Further, in the above example, the V-shaped grooves 112 , each measuring 3 μm in depth and 20 μm in width, are formed at an interval varying from 5 mm to 50 μm, but the dimensions and interval of the V-shaped grooves are not limited to these specific values, and other suitable values can be employed as needed.
[0075] In the above example, the V-shaped grooves are formed on the light conducting member 200 but, instead of the V-shaped grooves, use may be made of other patterns such as U-shaped grooves, a dot pattern (a pattern of dot-like microscopic projections and depressions) engraved or printed by laser, a random projection/depression pattern, an array of inverted square pyramid shaped depressions, random projections and depressions formed by chemical, plasma, electron beam, or other etching techniques, inverted V-shaped projections, and inverted U-shaped projections. Further, the V-shaped grooves, the U-shaped grooves, the dot pattern, the random projection/depression pattern, the array of inverted square pyramid shaped depressions, the random projections and depressions formed by etching, the inverted V-shaped projections, the inverted U-shaped projections, etc. described above may be formed, not on the light emitting surface of the light conducting member 200 , but on the back surface thereof opposite from the light emitting surface, or on both surfaces of the light conducting member 200 .
[0076] Further, instead of forming patterns such as the V-shaped grooves, U-shaped grooves, dot-like pattern, or random projection/depression pattern on the light conducting member 200 , a diffusing material may be added in the light conducting member 200 . As the diffusing material to be added, inorganic particles of glass, silica, mica, synthetic mica, calcium carbonate, barium sulfate, talc, montmorillonite, kaolin clay, bentonite, hectorite, etc., metal oxide particles of titanium oxide, zinc oxide, tin oxide, alumina, etc., or polymer particles of acrylic beads, styrene beads, benzoguanamine, silicone, etc., can be used.
[0077] The light deflecting means may also be provided in the form of a light diffusing material disposed inside each hollow cell 11 .
[0078] FIG. 8 shows one example of a panel type surface light emitting apparatus 3 that uses such a light diffusing material 300 .
[0079] The panel type surface light emitting apparatus 3 is similar in structure to the earlier described wall-hanging panel type surface light emitting apparatus 1 , except that the light diffusing material 300 is inserted in each hollow cell 11 in the hollow multilayer structure 10 and that no V-shaped grooves are formed on the light emitting surface of the hollow multilayer structure 10 , and therefore, only the differences in structure will be described below.
[0080] In the panel type surface light emitting apparatus 3 shown in FIG. 8 , the light 120 emitted from each LED 31 is reflected by the light diffusing material 300 disposed inside the hollow cell 11 and randomly emerges from the light emitting surface (light emitting side) of the hollow multilayer structure 10 .
[0081] As the light diffusing material 300 , use can be made of particles of highly reflective metal, particles of superfine fibers containing titanium oxide, particles of PET-based nonwoven fabric, particles of highly reflective tape or Japanese paper, or particles produced by adding a diffusing material in an optically transparent resin.
[0082] The above is an illustrated example in which the light deflecting means is provided in the hollow multilayer structure (see FIG. 2 ), an example in which the light deflecting means is provided in the light conducting member (see FIG. 6 ), and an example in which the light deflecting means is provided in the form of a light diffusing material (see FIG. 8 ). However, it is to be understood that these three methods can be suitably combined for use.
[0083] In this way, by incorporating the light deflecting means in the hollow multilayer structure 10 , it is possible to achieve a surface light emitting apparatus using light emitted from LEDs. According to the surface light emitting apparatus of the present invention, since the light emitted from each LED can be efficiently conducted and diffused by the use of the hollow multilayer structure 10 , a light-weight surface light emitting structure simple in construction can be provided. Furthermore, since the hollow multilayer structure is constructed from a plurality of hollow cells, each hollow cell can be illuminated with a differently colored light and different timing by providing a light source for each hollow cell.
[0084] FIG. 9 shows one example illustrating how the light emitting surface of the hollow multilayer structure is illuminated with the colored lights emitted from the respective LEDs.
[0085] In the example shown in FIG. 9 , the ribs 14 partitioning the hollow multilayer structure 10 into the plurality of hollow cells 11 are transparent as shown in FIG. 4 . It is also assumed that the red and blue LEDs are arranged in alternating fashion to illuminate the respective hollow cells 11 as shown in FIG. 9 . In this case, the red and blue colored lights entering the respective hollow cells 11 are additively mixed only in a region near the rib 14 (the region 302 ), and the resulting magenta colored light emerges from the light emitting surface of the hollow multilayer structure 10 . On the other hand, the center regions of the respective hollow cells illuminate in the respective colors (the region 301 in red color and the region 303 in blue color) generally producing a red/blue stripe pattern on the light emitting surface of the hollow multilayer structure 10 .
[0086] In this way, in the wall-hanging panel-type surface light emitting apparatus 1 to 3 using the hollow multilayer structure 10 whose ribs 14 are transparent, the colored lights emitted from the plurality of LEDs 31 can be mixed together to produce color illumination greater in variety and richer in expressiveness than is possible with one LED 31 alone.
[0087] FIG. 10 shows a perspective view of an alternative hollow multilayer structure.
[0088] The difference between the hollow multilayer structure 400 shown in FIG. 10 and the hollow multilayer structure 10 shown in FIG. 4 is that the ribs 414 partitioning the hollow multilayer structure 400 shown in FIG. 10 are opaque. The reflectance of each rib 414 to visible light is preferably 50% or higher, and more preferably 70% or higher. This can be accomplished, for example, by coating each rib 414 with a titanium-oxide-containing paint or by forming a vaporized Ag or Al film on each rib 414 .
[0089] FIG. 11 shows another example illustrating how the hollow multilayer structure is illuminated with the colored lights emitted from the respective LEDs.
[0090] In the example shown in FIG. 11 , the ribs 414 partitioning the hollow multilayer structure 400 into the plurality of hollow cells 11 are opaque as shown in FIG. 10 . It is also assumed that the red and blue LEDs are arranged in alternating fashion to illuminate the respective hollow cells 11 as shown in FIG. 11 . In this case, the red and blue colored lights entering the respective hollow cells 11 do not mix between them, but emerge independently of each other from the respective hollow cells 11 to illuminate the light emitting surface of the hollow multilayer structure 400 with the respective colored lights.
[0091] In this way, in the wall-hanging panel type surface light emitting apparatus 1 to 3 using the hollow multilayer structure 400 whose ribs 414 are opaque, the colored lights emitted from the plurality of LEDs 31 can be output without being mixed between the respective hollow cells. For example, if colored lights identical in hue, but different in lightness are emitted from the respectively adjacent LEDs, the light emitting surface of the surface light emitting apparatus can be illuminated with gradations of colored light. Further, if the colored lights being emitted from the plurality of LEDs 31 at predetermined intervals of time are changed as time elapses, a display of a moving color like a neon sign can be produced.
[0092] FIG. 12 is a front view of a floor-standing panel type surface light emitting apparatus 4 as viewed facing the light emitting side thereof when the surface light emitting apparatus according to the present invention is constructed as a floor-standing panel. FIG. 13 is a cross-sectional view taken along line BB′ in FIG. 12 .
[0093] In the floor-standing panel type surface light emitting apparatus 4 shown in FIGS. 12 and 13 , the same component elements as those in the earlier described wall-hanging panel type surface light emitting apparatus 1 are designated by the same reference numerals, and the description of such elements will not be repeated here. As shown in FIGS. 12 and 13 , the floor-standing panel type surface light emitting apparatus 4 comprises a hollow multilayer structure 10 , a frame member 22 , an LED circuit substrate 30 , and LEDs 31 . The hollow multilayer structure 10 is essentially the same as that described in connection with the wall-hanging panel-type surface light emitting apparatus 1 , the only difference being the overall shape.
[0094] As shown in FIG. 13 , in the floor-standing panel-type surface light emitting apparatus 4 , a color filter 60 for adjusting the hue of the light emitting surface and a protective plate 62 formed from a PC resin are provided on the light emitting surface of the hollow multilayer structure 10 (on the upper surface in FIG. 13 ), and a reflective sheet 43 is disposed on the back surface side of the hollow multilayer structure 10 . Further, a reinforcing block 23 is placed between the circuit substrate 30 and the frame member 22 . A pressure sensor 52 is mounted on the back surface of the hollow multilayer structure 10 at a position substantially centralized in the floor-standing panel type surface light emitting apparatus 4 . The sensor can be selected from among various known sensors such as a sensor for detecting infrared radiation, photocurrent, sound, temperature, vibration, magnetism, or humidity.
[0095] In use, the floor-standing panel-type surface light emitting apparatus 4 is installed so as to be embedded in the floor of a passage, corridor, etc., for example, in a public facility. The floor-standing panel-type surface light emitting apparatus 4 may be used as an illumination apparatus for continuously illuminating the passage, or as a guide light for indicating an emergency exit by illuminating only at the time of emergency, or as an illumination apparatus that is turned on by the action of the pressure sensor 52 only when the user steps on the floor-standing panel-type surface light emitting apparatus 4 .
[0096] FIG. 14 is a perspective view showing a double-sided illumination panel-type surface light emitting apparatus 5 when the surface light emitting apparatus according to the present invention is constructed as a double-sided illumination panel. FIG. 15 is a cross-sectional view taken along line CC′ in FIG. 14 .
[0097] As shown in FIGS. 14 and 15 , the double-sided illumination panel type surface light emitting apparatus comprises a hollow multilayer structure 500 , a frame member 520 , a first circuit substrate 530 , a first LED array 531 , a second LED array 532 , and a second circuit substrate 533 . The configuration of the first circuit substrate 530 and the first LED array 531 and the configuration of the second LED array 532 and the second circuit substrate 533 are the same as that illustrated in the example of the wall-hanging panel type surface light emitting apparatus 1 shown in FIG. 3 , and therefore, the description thereof will not be repeated here. A first diffusing sheet 540 , a first lens sheet 541 , and a second diffusing sheet 542 are formed one on top of another in this order on the first light emitting surface side (the side indicated by arrow D) of the hollow multilayer structure 500 . Likewise, a third diffusing sheet 543 , a second lens sheet 544 , and a fourth diffusing sheet 545 are formed one on top of another in this order on the second light emitting surface side (the side indicated by arrow E) of the hollow multilayer structure 500 .
[0098] FIG. 16 is a perspective view showing the hollow multilayer structure 500 .
[0099] The hollow multilayer structure 500 is constructed by integrally forming a plurality of hollow cells 510 and 511 one alternating with the other along the longitudinal direction thereof. More specifically, the structure comprises a first top plate 512 , a second top plate 513 , and a plurality of ribs 514 . In the hollow multilayer structure 500 shown in FIG. 16 , the ribs 514 are sandwiched between the first and second top plates 512 and 513 by being alternately slanted in opposite directions, and partition the structure into the plurality of hollow cells 510 and 511 . Further, like the ribs 414 shown in FIG. 10 , the ribs 514 are opaque so that color mixing does not occur between adjacent hollow cells. The method of forming the opaque ribs 514 is the same as that for the ribs 414 shown in FIG. 10 , and the description will not be repeated here.
[0100] In FIG. 16 , the hollow cells 510 and 511 each measure 750 mm in length a, 6 mm in horizontal width b, and 6 mm in vertical width (height) c, and the first top plate 512 , the second top plate 513 , and the ribs 514 are all 0.33 mm in thickness. The above hollow cell size is only one example, and other dimensions may be employed. The hollow multilayer structure 500 is formed from a PC resin, but it may be formed from a PMMA resin, an MS resin, a polyester resin such as PET, a PSt resin, a COP resin, a COC resin, an olefin resin such as a PP resin or a PE resin, a PVC resin, an ionomer resin, glass, etc.
[0101] Further, as shown in FIG. 16 , the first LED array 531 is arranged so that the respective LEDs are inserted in the plurality of hollow cells 510 and 511 , and the second LED array 532 is also arranged so that the respective LEDs are inserted in the plurality of hollow cells 510 and 511 . That is, one of the LEDs in the first LED array 531 is mounted at one end of one of the hollow cells 510 and 511 , while one of the LEDs in the second LED array 532 is mounted at the other end. Alternatively, the first and second LED arrays 531 and 532 may be arranged so that the LEDs are each mounted only at one end of each of the hollow cells 510 and 511 , rather than mounting the LEDs at both ends.
[0102] In the hollow multilayer structure 500 , V-shaped grooves 502 (each measuring 3 μm in depth and 20 μm in width, with groove interval varying from 5 mm to 50 μm) are formed as light deflecting means extending along a direction orthogonal to the longitudinal direction of the hollow cell over the entire first light emitting surface (on the side indicated by arrow D), and likewise, V-shaped grooves 504 (each measuring 3 μm in depth and 20 μm in width, with groove interval varying from 5 mm to 50 μm) are formed as light deflecting means extending along a direction orthogonal to the longitudinal direction of the hollow cell over the entire second light emitting surface (on the side indicated by arrow E).
[0103] Accordingly, the light emitted from the first LED array 531 and entering the hollow cells 510 is deflected by the V-shaped grooves 502 and emerges from the first light emitting surface (on the side indicated by arrow D). On the other hand, the light emitted from the second LED array 532 and entering the hollow cells 511 is deflected by the V-shaped grooves 504 and emerges from the second light emitting surface (on the side indicated by arrow E). In this way, the double-sided illumination panel-type surface light emitting apparatus 5 that can emit light from both sides can be achieved using one hollow multilayer structure 500 .
[0104] Further, in the double-sided panel-type surface light emitting apparatus 5 , any type of light deflecting means used in the wall-hanging panel-type surface light emitting apparatus 1 can be used.
[0105] While the surface light emitting apparatus of the present invention has been described by dealing with examples in which the invention is applied to a wall-hanging panel type apparatus, a floor-standing panel type apparatus, and a double-sided panel type apparatus, respectively, it will be recognized that the surface light emitting apparatus of the invention can be adapted for use in many applications other than the panel-type, for example, as an indoor or outdoor illumination apparatus, furniture, etc., by taking advantage of its light-weight and simple construction. Furthermore, the surface light emitting apparatus of the invention can be mounted not only on a wall, but also on any other indoor or outdoor surface or object such as a pillar, ceiling, floor, baseboard, etc.
[0106] As described above, when the surface light emitting apparatus of the invention is used, since a color stripe pattern can be produced on the light emitting surface by illuminating each hollow cell with a differently colored light, the “principle of order” that colors selected based on orderly or simple geometric relations harmonize well can be satisfied by the stripe that describes a color space comprised of equidistant colors. Furthermore, when the surface is illuminated with a stripe-shaped color pattern by illuminating the hollow cells so as to express familiar colors existent in nature and their changes in conformance with the “principle of familiarity,” illumination particularly pleasing and appealing to human senses can be achieved. | An object of the invention is to provide a thin, low-power consumption, light-weight, and inexpensive surface light emitting apparatus using a hollow multilayer structure in combination with LEDs, and a method of light emission for the same. More specifically, the invention provides a surface light emitting apparatus comprising: a hollow multilayer structure formed from a plurality of hollow cells; a light source for emitting light into the hollow multilayer structure through an end face thereof containing a cell opening; and optical means for causing the light introduced through the cell opening-containing end face of the hollow multilayer structure to emerge from a surface of the hollow multilayer structure. | 6 |
REFERENCE TO PRIORITY DOCUMENT
[0001] This application is a continuation of co-pending U.S. patent application Ser. No. 11/904,308, titled, “SPECULUM”, filed Sep. 25, 2007, to James Marino, which in turn claims priority to U.S. Provisional Patent Application Ser. No. 60/847,481, filed Sep. 26, 2006. Priority of the aforementioned filing date is hereby claimed and the disclosure of the Provisional Patent Application is hereby incorporated by reference in its entirety.
BACKGROUND
[0002] The present disclosure relates to a system for accessing and channeling tissue, such as bone tissue.
[0003] It is often necessary to access regions of anatomical tissue such as for insertion of a tool for treating or sampling the tissue. For example, a tool is sometimes used to obtain a core sample of biological material such as to diagnose defects or ailments. To obtain a sample, an instrument me be used to remove a portion or a “core sample” from surrounding biological material. In order for the tool to provide a proper approach to the relevant tissue, there is a need for systems and methods that facilitate in gaining access to tissue.
SUMMARY
[0004] There is a need for improved devices and methods for accessing and channeling through biological tissue.
[0005] In one embodiment, disclosed is a bone access tool including a handle assembly having a first portion and a second portion that are movable relative to one another; a speculum assembly coupled to the handle assembly, the speculum assembly having a first speculum member; a second speculum member movably positioned relative to the first speculum member, wherein the first and second speculum members define an internal shaft therebetween arranged about a central axis, and the first and second speculum members define a tapered shape when positioned adjacent one another, the tapered shape gradually reduces in size from a proximal rim to a distal edge of the speculum assembly; and at least one rib extending outwardly from each of the first and second speculum members, the rib having an upper surface and an inclined lower surface. Actuation of the handle assembly causes the first speculum member and second speculum member to spread apart from one another about the central axis so as to retract anatomical tissue and widen a size of the internal shaft for deploying a tool into the internal shaft between the speculum members.
[0006] In an embodiment, disclosed is a method of accessing bone, including providing an access tool having a handle assembly coupled to a speculum assembly formed of two speculum members that collectively form a substantially conical shape with a pointed distal edge; navigating the access tool through anatomical tissue so that the pointed distal edge of the speculum assembly is located at a desired anatomical location; actuating the handle to cause the speculum members to separate from one another to retract anatomical tissue and to form a passageway between the speculum members; and positioning an elongated tool in the passageway and in contact with the anatomical location.
[0007] Other features and advantages will be apparent from the following description of various embodiments, which illustrate, by way of example, the principles of the disclosed devices and methods.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 shows a perspective view of a tissue access and channel formation system.
[0009] FIG. 2 shows an enlarged view of a speculum assembly of the system with a locking member mounted onto the speculum assembly.
[0010] FIG. 3 shows a side view of the system in cross-section.
[0011] FIG. 4 shows a side view of the speculum assembly along line G-G of FIG. 3 .
[0012] FIG. 5A shows a guide wire or guide pin to be inserted into a region of the iliac crest of the pelvis.
[0013] FIG. 5B shows the system being guided along the inserted guide pin toward the iliac crest.
[0014] FIG. 5C shows the system with the speculum assembly in a possible desired orientation relative to the iliac crest.
[0015] FIG. 5D shows a locking member removed from the speculum assembly.
[0016] FIG. 5E shows the system with the speculum members displaced from one another to displace and expand surrounding tissue.
[0017] FIGS. 5F and 5G show the system with a coring tool positioned at least partially within the passageway between the speculum members.
DETAILED DESCRIPTION
[0018] FIG. 1 shows a perspective view of a tissue access and channel formation system 100 . The system 100 includes a handle assembly 105 and a conical speculum assembly 110 attached to the handle assembly 105 . The handle assembly 105 includes a pair of arms 115 that are pivotably attached to one another about a pivot axis 120 . The arms 115 pivot about a circular pivot member 121 such as when a user actuates the handle assembly 105 . The pivot member 121 can be ratcheted such that movement of the arms 115 relative to one another is controlled by a ratchet mechanism. The arms 115 are shaped and contoured such that the arms extend away from one another at the pivot member 121 and are positioned adjacent one another along a region adjacent the speculum assembly 110 .
[0019] The speculum assembly 110 is pivotably attached to the handle assembly 105 via a pair of speculum couplers 130 . The speculum assembly 110 includes a pair of semi-conical speculum members 135 that collectively form a conical shape when positioned adjacent one another, as shown in FIG. 1 . The conical speculum assembly 110 is symmetric about a central axis 410 . In the illustrated embodiment, the speculum assembly 110 is widest at a proximal rim 140 and gradually tapers in diameter toward a distal edge 145 that is pointed. The conical shape facilitates soft tissue penetration and dilation of a surgical access envelope during use of the device, as described below. It should be appreciated that the shape of the speculum assembly 110 can vary from the conical shape and can have other shapes that facilitate soft tissue penetration and dilation of a surgical access envelope. For example, the speculum assembly 110 can have a shape that generally tapers moving in the distal direction with the taper being linear or curvilinear.
[0020] A speculum cap 150 is removably positioned on the speculum assembly 110 at the proximal rim 140 . The speculum cap 150 forms a flat or generally flat upper surface. The upper surface of the speculum cap 150 provides a location where a striking tool, such as hammer, mallet, or the like, can be used to strike the speculum assembly 110 and provide a downward or distal force to the assembly. This can be desirable when driving the distal edge of the speculum assembly 110 into tissue. The speculum cap 150 can be coupled to the speculum assembly 110 in various manners. For example, the speculum cap 150 can fit within a seat in the upper rim 140 of the speculum assembly 110 or it can hinged or can have locked detent engagement feature with the speculum assembly 110 . The speculum cap 150 can be removed from the speculum assembly 110 to expose an internal speculum shaft 320 ( FIG. 3 ) positioned inside the speculum assembly 110 between the speculum members 135 , as described in detail below.
[0021] The speculum cap 150 can include an opening or aperture that communicates with the internal speculum shaft 320 . The opening provides a passageway through which a guide pin or guide wire can be inserted. In this regard, the opening desirably has a shape or contour that facilitates insertion of the guide wire into the opening. For example, the opening can be at least partially conical or can have a countersunk feature that facilitates “blind” introduction of the guide wire into the opening.
[0022] FIG. 2 shows an enlarged view of the speculum assembly 110 with a locking member 205 mounted onto the speculum assembly 110 . The locking member 205 is a clamp-like member that maintains the speculum members 135 in a fixed spatial relationship. For example, the locking member 205 can hold the two arms 115 together to prevent them from spreading apart and thereby prevent spreading of the speculum members 135 . In this regard, the locking member 205 includes a pair of flanges that are positioned on opposite sides of the arms 115 to oppose outward motion of the arms 115 . Thus, when the locking member 205 is mounted on the system, the arms 115 and the attached speculum members 135 are prevented from separating from one another. The locking member 205 is removably mounted on the speculum assembly 110 . A pair of locking member pins 215 removably mate with the locking member 205 and the speculum coupler 130 . The locking member pins 215 can be slidably uncoupled from the speculum coupler 130 to release the locking member 205 from the speculum assembly 110 .
[0023] With reference still to FIG. 2 , a guide slot 210 extends through the locking member 205 . The slot 210 communicates with the internal speculum shaft 320 ( FIG. 4 ) located between the speculum members 135 . The slot 210 is aligned or substantially aligned with the central axis 410 of the speculum assembly 110 . A guide pin or guide wire can be positioned through the slot 210 and the internal speculum shaft 320 to assist in navigating through tissue during use of the system, as described more fully below.
[0024] FIG. 3 shows a side view of the system in cross-section. The opposite side view is a mirror image of the side view shown in FIG. 3 . Each arm 115 extends along a generally longitudinal axis that intersects the central axis 410 . The end regions of the arms 115 curve downwardly toward the speculum assembly 110 . Each arm 115 is pivotably attached to a respective speculum coupler 130 via a pivot pin 305 . Each pivot pin 305 defines a pivot axis about which the arm 115 can pivot relative to the speculum assembly. Thus, the handle assembly 105 is hinged relative to the speculum assembly 110 . As mentioned, the arms 115 are pivotably attached to one another via the circular pivot member 121 , which can be secured to the arms 115 via a pivot screw that defines a pivot axis about which the arms 115 pivot relative to one another.
[0025] FIG. 3 shows the internal speculum shaft 320 that is positioned inside the speculum assembly 110 . The speculum shaft 320 has a conical shape with a gradually decreasing diameter that is largest at the proximal rim 140 of the speculum assembly 110 . The speculum shaft 320 gradually tapers in diameter moving toward the distal edge 145 of the speculum assembly 110 . A distal opening 325 is at the distal edge of the speculum assembly 110 such that the speculum shaft 320 is open at the distal edge 145 . The opening 325 aligns or generally aligns along a common axis 410 with the internal speculum shaft 320 , the opening in the speculum cap 150 , and the guide slot 210 ( FIG. 2 ) of the locking member 205 . This permits a guide wire or guide pin to be inserted through the entire speculum assembly 110 and locking member 205 to assist in navigation of the system through tissue during use.
[0026] FIG. 4 shows a side view of the speculum assembly 110 along line G-G of FIG. 3 . As discussed, the speculum assembly 110 includes a pair of speculum members 135 that are semi-conical in shape. The speculum members 135 are referred to herein individually as speculum member 135 a and speculum member 135 b. The speculum members 135 collectively form a conically-shaped speculum when positioned adjacent one another as in FIG. 4 . The speculum members 135 have walls that meet along a central plane that intersects with the central axis 410 of the conical speculum assembly 110 . The central plane is perpendicular to a plane defined by FIG. 4 . The speculum members 135 can mate with one another along the adjacent walls such as in an interdigitating manner in order to stabilize the speculum members 135 relative to one another during use of the system 100 .
[0027] With reference still to FIG. 4 , one or more protruding flanges or ribs 405 are interspersed along the speculum members from the proximal rim 140 to the distal edge 145 . The illustrated embodiment includes three annular ribs 405 although it should be appreciated that additional ribs 405 or less ribs 405 can be used. The ribs 405 extend radially outward relative to the central axis 410 of the speculum assembly 110 . Each rib 405 has a bottom surface 415 and an upper surface 420 . In the illustrated embodiment, the bottom surface 415 of each rib 405 is upwardly sloped. The upper surface 420 of each rib 405 is horizontal. The upwardly sloped bottom surfaces 415 assist in displacement of tissue upon insertion of the system 100 into tissue and also assist in rotation of the speculum. It should be appreciated that the ribs 405 can have other shapes.
[0028] FIGS. 5A-5G are diagrams of an exemplary tissue access and channel formation method that uses the system shown in FIG. 1 . In an exemplary embodiment, the device and method are used within or in the region of a person's vertebral bones. For example, the device and method can be employed to gain access to a mammalian patient's pelvis P, such as in the region of the iliac crest. With reference to FIG. 5A , a guide wire or guide pin 505 is inserted into a region of the iliac crest. One or more guidance systems can be used to navigate the guide pin 505 to a desired location of the iliac crest. For clarity of illustration, FIGS. 5A-5G schematically represent the pelvis P and do not include anatomical structures or tissue that are present around the pelvis P.
[0029] The tissue access system 100 is then placed over the guide pin 505 and navigated to a desired location of the iliac crest. In this regard, an incision may be made in surrounding tissue and the conical speculum assembly 110 inserted through the incision. The handle assembly 105 can remain outside of the patient's skin. As discussed, the locking member 205 has a guide slot 210 that communicates with the internal speculum shaft 320 . The tissue access system 100 is guided to the desired iliac crest location by sliding the guide slot 210 and the internal speculum shaft 320 along the guide pin 505 . FIG. 5B shows the system 100 being guided along the guide pin 505 toward the iliac crest.
[0030] The system 100 can advantageously be rotated in various manners as the system navigates through the tissue. For example, the handle assembly 105 and speculum assembly 110 can be rotated about the guide pin 505 . The handle assembly 105 can also rotate relative to the speculum assembly 110 about the pivot pin 305 ( FIG. 3 ). In this manner, the handle assembly 105 can be maneuvered to a desired orientation, such as to enhance the distraction, cut the fascia and tissue adjacent to the crest and correctly orient the speculum assembly 110 . FIG. 5C shows the system 100 with the speculum assembly in a possible desired orientation relative to the iliac crest. The system 100 is positioned such that the distal edge of the speculum assembly 110 contacts the iliac crest. As mentioned, a hammer or mallet can be used to apply a force to the speculum assembly 110 for driving the speculum assembly 110 into tissue.
[0031] After the system 100 has been properly orientated, the physician may remove the locking member 205 from the speculum assembly 110 . FIG. 5D shows the locking member 205 removed from the speculum assembly 110 . As mentioned, the locking member pins 215 can be removed to release the locking member 205 from the system 100 . With the locking member 205 removed, the speculum members 135 are free to be separated from one another. This is accomplished by the physician squeezing the arms 115 of the handle assembly 110 toward one another. This causes the distal regions of the arms 115 to pivot away from one another, thereby displacing the speculum members 135 relative to one another. FIG. 5E shows the system 100 with the speculum members 135 displaced from one another such that the speculum members 135 displace and expand surrounding tissue. During separation of the speculum members 135 , the ribs 405 stabilize the speculum assembly 110 against the surrounding tissue. A passageway is thereby formed between the speculum members 135 wherein the passageway can be used to visualize the anatomy and/or deliver one or more tools to the iliac crest. In an embodiment, one or more anchor pins 515 can be inserted into the speculum members 135 to immobilize them in the displaced positions.
[0032] FIGS. 5F and 5G show the system with a tool 520 positioned at least partially within the passageway between the speculum members 135 . The tool 520 can be any of a variety of tools for treatment or diagnosis of the tissue accessed by the system 100 . In an embodiment, the tool 520 is a tool that is adapted to core into the bone and obtain a sample of the bone. After the tool 520 is used for its intended purpose, the tool 520 can be removed from the passageway between the speculum members 135 . The anchor pins 515 can then be removed and the separation between the speculum members 135 can be reduced by operating the handle assembly 105 . The system 100 can then be removed by navigating out of the tissue. The generally horizontal upper surfaces 420 of the ribbing is generally perpendicular to the direction of withdrawal to reduce the potential for ejection with soft tissue tensioning. The locking member 205 can be re-attached prior to removal of the system 100 . In addition, the handle assembly 105 can be rotated during removal to ease removal.
[0033] Although embodiments of various methods and devices are described herein in detail with reference to certain versions, it should be appreciated that other versions, embodiments, methods of use, and combinations thereof are also possible. Therefore the spirit and scope of the snowboard binding should not be limited to the description of the embodiments contained herein. | A bone access tool including a handle assembly and speculum assembly coupled to the handle assembly for accessing and channeling through biological tissue is described. The handle assembly has first and second portions that are movable relative to one another. The speculum assembly has first and second speculum members movably positioned relative to one another. The speculum members define an internal shaft arranged about a central axis and a tapered shape when positioned adjacent one another. The tapered shape gradually reduces in size from a proximal rim to a distal edge of the speculum assembly. Actuation of the handle assembly causes the first speculum member and second speculum member to spread apart from one another about the central axis so as to retract anatomical tissue and widen a size of the internal shaft for deploying a tool into the internal shaft between the speculum members. | 0 |
RELATED APPLICATIONS
The present invention is a continuation-in-part of the patent application Ser. No. 11/117,053, filed on Apr. 28, 2005, entitled “Method of Producing a Reflective Design on a Substrate and Apparatus”.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
Not Applicable
THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT
Not Applicable
REFERENCE TO A SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING
Not Applicable
BACKGROUND OF THE INVENTION
Garments for running, cycling, footwear, hats, backpacks, jackets, pet collars, and leashes all utilize photo-reflective material for the purpose of increasing the wearer's visibility and safety after dark. This material is typically attached to the garment by sewing or is adhered using heat activated adhesive. One problem with the addition of reflective material is that it typically reduces the aesthetics of the garment in daylight. As a result, many consumers are unwilling to take advantage of the beneficial features provided by reflective materials on garments.
Thus there exists a need for more visually appealing garments that have light reflecting material.
BRIEF SUMMARY OF INVENTION
A method of producing a reflective design that overcomes these and other problems includes the steps of lasering a pattern on an adhesive side of a reflective laminate material. The reflective laminate material is applied to a substrate. A carrier layer of the reflective laminate is removed to reveal a reflective design on the substrate. This method allows for highly customized reflective designs at a reasonable cost that are very visually appealing. The substrate may be a textile, paper, or suitable decal material. The substrate may be a garment or may be a patch that is sewn onto a garment or applied to the garment with an adhesive, or a decal that can be applied to an object with a smooth surface.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
FIG. 1 is a block diagram of a system for producing a reflective design on a textile in accordance with one embodiment of the invention;
FIG. 2 is an example of a reflective design on a textile in accordance with one embodiment of the invention;
FIG. 3 is a flow chart of the steps used in producing a reflective design on a textile in accordance with one embodiment of the invention;
FIG. 4 is a cross sectional view of a reflective laminate in accordance with one embodiment of the invention;
FIG. 5 is a flow chart of the steps used in producing a reflective design in accordance with one embodiment of the invention; and
FIG. 6 is a flow chart of the steps used in producing a reflective design in accordance with one embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
The present invention increases the aesthetic appeal of garments that have a reflective film. In one embodiment, the reflective film is patterned on its surface with a laser. In another embodiment, the adhesive on the backside of the reflective film is patterned with a laser, causing portions of the reflective film to not adhere to the substrate. Once laminated, the lasered film creates a reflective pattern. The pattern can be text or graphics.
FIG. 1 is a block diagram of a system 10 for producing a reflective design on a textile in accordance with one embodiment of the invention. A reflective film 12 is laminated or sewn to a substrate 14 . In one embodiment, the substrate 14 is a textile product. A pattern or design is put into a computer 16 . The computer 16 directs a laser 18 and associated optics to focus the laser beam 20 onto a surface 22 of the reflective film 12 . It is thought that the laser beam partially ablates and partially carbonizes the surface of the reflective material. The reflective film 12 has tiny glass beads reflectors embedded in a polymer. Where the surface is carbonized the surface looks black and the glass beads are no longer able to enhance the reflection of light. Note that the appearance of the finished product is substantially increased by only having the surface of the reflective film patterned by the laser. To achieve adequate results, the laser intensity and dwell on a particular spot need to be precisely set or the laser may not sufficiently mark the reflective film or it may burn through the reflective film. Ideally, the surface is patterned so lightly that to a user's touch the laser patterned area appears to be at essentially the same level as the rest of the front surface of the reflective film. Note that the pattern may be made by a number of dots where the laser has been focused on the surface of the reflective material. The density of the dots can be used to create shades of grey. On a colored reflective film, variations in dot density results in duotones.
In one embodiment, the laser beam is positioned at different spots on a stationary reflective film. Conversely, it is possible to move the reflective film and have the laser beam be stationary.
FIG. 2 is an example of a reflective design on a textile in accordance with one embodiment of the invention. A textile 30 has a reflective film 32 laminated to the textile 30 . Commonly, heat activated adhesive is used to laminate the reflective film 32 to the textile 30 . The reflective film 32 may be laminated by sonic welding, RF welding or any other of the well known laminating techniques. A design 34 is fashioned by a laser onto the surface of the reflective film 32 . The appearance of the overall product can be enhanced by selecting a textile 30 that has smooth surface commonly associated with a higher thread count and thinner yarn. For some applications like collars, it is helpful if the webbing of the textile is braided at approximately 45 degrees to the length of the collar. When this is done, bending the collar does not result in bumps from the textile in the reflective film. Before the reflective film 32 is laminated to the textile 30 the textile may be subjected to heat and pressure. This further tightens the weave of polymer based textiles. As a result, the reflective film sits flat on the textile rather than having a bumpy looking surface. In one embodiment, the reflective film is treated with an ink before it is patterned with the laser. The ink may be an alcohol based ink.
FIG. 3 is a flow chart of the steps used in producing a reflective design on a textile in accordance with one embodiment of the invention. The process starts, at step 100 . A high thread count, thin yarn textile at step 102 . In one embodiment, the textile is a polymer based textile. In another embodiment, the textile is a polymer based textile, but not nylon. Pressure and heat are applied to a surface of the textile at step 104 . In one embodiment, only heat is applied to the surface of the textile. The reflective film is laminated to the textile at step 106 . The graphics and text design is input into a computer at step 108 . An ink may be applied to the reflective film at step 110 . At step 112 , the laser is focused onto the reflective film with the appropriate power and dwell settings to create the design, which ends the process at step 114 .
FIG. 4 is a cross sectional view of a reflective laminate 120 in accordance with one embodiment of the invention. The reflective laminate 120 has a carrier layer 122 , which protects the reflective film 124 . An adhesive 126 , commonly heat and/or pressure activated, is on an underside of the reflective film 124 . An adhesive protection layer 128 protects the adhesive 126 and keeps if from accidentally becoming adhered to the wrong surface.
In order to create a pattern in the adhesive laminate 120 , the adhesive protection layer 128 is removed. A laser, such as laser 18 in FIG. 1 , then creates a pattern in the adhesive. By appropriately adjusting the output settings of the laser the adhesive is ablated at selected locations. Next, the reflective laminate 120 with the patterned adhesive is applied to a substrate, such as substrate 14 in FIG. 1 . Application may include the use of heat or pressure or both to cause the patterned reflective laminate to adhere to the substrate. The carrier layer 122 is then removed. When the carrier layer 122 is removed areas of the reflective film 124 that had adhesive ablated by the laser are also removed. As a result, a pattern of the reflective film 124 and the substrate is formed. Note that because the pattern is created on the adhesive backside of the reflective film 124 , the image has to be a mirror image of the desired end result. In one embodiment, the top side 22 ( FIG. 1 ) of the reflective film 124 is also patterned with the laser, as discussed with respect to FIGS. 1-3 . Commonly the substrate will be a textile. The textile may be a finished garment, a garment panel, or the textile may form a patch. The patch may be sewn onto a garment or may have an adhesive backing to form an iron-on patch. Alternatively, the substrate can be paper or a material used to form a decal. Note that the laser is utilized to ablate the adhesive so as used in this embodiment lasering means a process that vaporizes or neutralizes the adhesive.
FIG. 5 is a flow chart of the steps used in producing a reflective design in accordance with one embodiment of the invention. The process starts, step 130 , by lasering a pattern on an adhesive side of a reflective laminate material at step 132 . The reflective laminate material is applied to a substrate at step 134 . At step 136 the carrier layer of the reflective laminate, as well as the non-adhered laminate material is removed, which ends the process at step 138 .
FIG. 6 is a flow chart of the steps used in producing a reflective design in accordance with one embodiment of the invention. The process starts step 140 , by creating a design in a reflective film at step 142 . At step 144 the reflective film is applied to a substrate, which ends at step 146 . In one embodiment, steps 142 and 144 are reversed. Note that the substrate may be a textile, paper or a suitable decal material such as polyester film. The textile may be a garment or a patch. The patch may be sewn onto a garment or may be an iron-on patch. For an iron-on patch, the back side of the patch is a heat or pressure or combination adhesive. Commonly the laser patterned reflective film is attached to the patch textile by a heat and/or pressure adhesive. It is possible to attach the reflective film by applying heat or pressure by using a non-stick guard to protect the adhesive backside of the patch. Thus even if the adhesive on the patch is melted it is contained by the non-stick guard, such as a sheet of Teflon. Once cooled, the patch easily peels off the Teflon with the adhesive intact. The patch can later be heat applied to a garment. Alternatively, by adjusting temperature, pressure, and/or dwell time, it is possible to adhere the reflective film to the patch without activating the adhesive on the backside of the patch.
In one embodiment, the patch is made with tabs that wrap around an article and adhere to each other, thus improving adhesion of a patch to articles such as pet collars
Thus there has been described a system and method for producing a reflective design on a substrate that results in more visually appealing garments that have light reflecting material.
While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alterations, modifications, and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alterations, modifications, and variations in the appended claims. | A method of producing a reflective design includes the steps of lasering a pattern on an adhesive side of a reflective laminated material. The lasering ablates the adhesive and causes these areas to not adhere. The reflective laminate material is applied to a substrate. A carrier layer of the reflective laminate is removed to produce a reflective design on the substrate. This method allows for highly customized designs at a reasonable cost that are very visually appealing. The substrate may be a textile, paper, or decal material. The textile may be the garment or may be a patch that is sewn onto a garment or applied to the garment with an adhesive. | 3 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an ozone generator with a first and a second metallic electrode, with a layer of enamel on the surface of the second electrode facing the first electrode and a discharge gap between the first electrode and the enamel layer.
The invention thereby makes reference to a prior art such as arises, for example, from U.S. Pat. Specification No. 3,954,586.
2. Discussion of Background
For very many processes, extremely large quantities of ozone of the order of magnitude of hundreds of kilograms to ton per hour are necessary, and consequently they can be carried out virtually only if compact high-power ozone generators which can produce such high quantities of ozone are available.
To increase the power density of ozonizers--whether with the dielectric in the form of a tube or in the form of a plate--in the past the dielectric glass has been replaced by dielectrics based on plastic or ceramic.
In an ozone generator, the quantity of ozone Y formed per unit of discharge area is namely proportional to the electric power W per unit of area:
Y=K·W
In first approximation, the electric power W is in turn proportional to the relative dielectric constant E and inversely proportional to the thickness D of the dielectric:
W =K'·E/d
If glass is used as dielectric, the relative dielectric constant E is around 5. For reasons of stability, the wall thickness of such glass dielectrics must be at least 1.5 mm.
German Offenlegungsschrift 2,658,913 discloses an ozone generator which comprises a cooled internal electrode, an external electrode and a high-voltage electrode arranged concentrically in between, which are in each case coated on their outer circumferential surface with a glass-enamel dielectric. German Pat. Specification 2,534,033 discloses a high-frequency tube ozone generator in which a dielectric layer of silicate enamel or glass is applied to each of the opposite surfaces of concentrically arranged metal tubes. German Offenlegungsschrift 2,617,059 discloses the use of a thin silica gel layer as dielectric in ozone generators, which layer is applied to self-supporting metal electrodes.
German Offenlegungsschrift 2,354,209 discloses an ozone generator which consists of a self-supporting ceramic tube as dielectric, which is covered on its outer circumferential surface by a metal layer of an electrode and in which a metal tube is arranged concentrically as counter-electrode. However, such a self-supporting ceramic tube cannot be dimensioned just as thin as desired and is also very fragile.
German Offenlegungsschrift 2,065,823 discloses an ozone generator of which the electrodes consist of decarbonized steel, which are coated with a thin ceramic layer as dielectric. However, such ceramic layers have to be stoved at relatively high temperatures, which can result in a troublesome distortion of the self-supporting metal electrodes.
German Auslegeschrift 2,618,243 discloses a dielectric for ozone generators which consists of a ceramic material with Al 2 O 3 , SiO 2 and at least one alkaline metal oxide or alkaline earth metal oxide and has a dielectric constant between 5 and 10 and is 0.5 mm to 1 mm thick.
U.S. Pat. Specification No. 4,690,803 and German Offenlegungsschrift 3,128,746, for example, disclose ozonizers with plastic dielectric, in particular such ozonizers with titanium dioxide-filled plastic dielectric.
In the case of all the non-glass dielectrics described above, in principle the power density, and consequently the ozone yield, can be increased.
According to the findings of the applicant, the surface of the dielectric has a decisive influence on the efficiency. Dielectrics based on ceramic or synthetic resin are inferior to glass dielectrics in this respect.
SUMMARY OF THE INVENTION
Accordingly, on the basis of the prior art, one object of the invention is to provide a dielectric of the type mentioned at the beginning which has a relatively high dielectric constant and a relatively high dielectric strength, so that a high ozone yield can be achieved with thin layers of an order of magnitude of 100 μm, and which is equal to glass dielectrics in terms of efficiency.
This object is achieved according to the invention by the enamel layer consisting of a plurality of enamel layers of different dielectric constants lying one on top of the other, the enamel layer adjacent to the discharge gap having a smaller dielectric constant than the enamel layer(s) lying underneath.
In this case, the enamel of the top layer is preferably an enamel based on iron or cobalt with a dielectric constant less than or equal to 6, while the enamel of the lower layer(s) is an enamel based on titanium with a dielectric constant greater than or equal to 10, or at least contains TiO 2 .
With the invention, dielectric capacities comparable to those of filled plastic dielectrics can be achieved with layer thicknesses less than 1 mm.
BRIEF DESCRIPTION OF THE DRAWING
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing, wherein the single figure represents a section through a tube ozonizer with a two-layered enamel dielectric.
DESCRIPTION OF THE PREFERRED EMBODIMENT
In the Figure, a first external metallic electrode in the form of a metal tube is denoted by 1, a second internal metallic electrode likewise in the form of a metal tube, preferably of high-grade steel, is denoted by 2. The second electrode 2 has on the surface facing the first electrode 1 a layer of, in the case of the example, two enamel layers 3, 4 lying one on top of the other. A discharge gap 5 as provided between the first electrode 1 and the two enamel layers 3, 4.
The lower layer 3--in a practical embodiment this consists of a plurality of individual layers of about 100 μm applied one after the other, with a total thickness of about 1 mm--consists of a titanium enamel (for example enamel 8380 of Messrs Ferro (Holland) B.V.) with increased titanium dioxide content. This addition of titanium dioxide allows dielectric constants in excess of 10 to be achieved. Such layers can be applied by known methods directly to steel tubes, preferably such tubes of high-grade steel.
For the purpose of achieving an optimum ozone yield, the uppermost enamel layer 4 consists of another enamel with small dielectric constant (≦6). Suitable for this in particular are enamels containing iron or cobalt, which are applied directly to the base layer(s) 3 with a thickness of 100-150 μm.
Examples of enamel layers are described, for example, in the "Email-Handbuch" (Enamel Handbook) of the abovementioned Messrs Ferro or else in U.S. Pat. Specification No. 3,954,586, column 17. All of the essential details of the coating operation are also explained in this publication.
To improve the ozone yield further, the inside of the external electrode 1 is provided with a further dielectric layer 6.
In applying a suitable dielectric layer to the inside surface of the metallic electrode 1, an ozone yield which corresponds to ozonizers fitted with glass dielectrics can also be obtained with dielectrics of high dielectric constant. The thickness of the dielectric coating may be between 10 μm and 1 μmm. A (material-dependent) minimum layer thickness is necessary in order to show the desired effect. If the layer thickness is too great, the total capacity of the ozonizer (series connection of the capacities) of the coating of the metal electrode 1 and of the dielectric 3, 4 is reduced to such an extent that the advantages of the high dielectric capacity are lost again. In addition, heat transfer between the gap and the (cooled) metal electrode 1 worsens. Since the applied electric voltage has to be held by the dielectric (3,4) itself, no special requirement is made on the electric strength of the coating (6).
In the case of external electrodes 1 of aluminum, the layer 6 may be an anodized oxide layer. Steel electrodes may likewise be internally anodized by previous coating with aluminum. In addition, however, coating with enamel, spray coating or coating with ceramic adhesives or casting compounds are also suitable.
The measures described above for increasing the ozone yield were described with reference to a tube ozonizer. It goes without saying that they can be applied to ozonizers of a different geometry, in particular plate ozonizors, without departing from the scope of the invention.
Obviously, numerous modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein. | In an ozone generator with enamel dielectric, to increase the ozone yield, the latter is built up on at least two enamel layers, the layer (4) facing the discharge space (5) having a smaller dielectric constant (≦6) than the layer (3) lying underneath. | 2 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] Reference is made to and this application claims priority from and the benefit of U.S. Provisional Application Ser. No. 60/649,383, filed Feb. 2, 2005, and entitled PARALLEL FLOW EVAPORATOR WITH CRIMPED CHANNEL ENTRANCE, which application is incorporated herein in its entirety by reference.
BACKGROUND OF THE INVENTION
[0002] This invention relates generally to air conditioning, heat pump and refrigeration systems and, more particularly, to parallel flow evaporators thereof.
[0003] A definition of a so-called parallel flow heat exchanger is widely used in the air conditioning and refrigeration industry and designates a heat exchanger with a plurality of parallel passages, among which refrigerant is distributed and flown in the orientation generally substantially perpendicular to the refrigerant flow direction in the inlet and outlet manifolds. This definition is well adapted within the technical community and will be used throughout the text.
[0004] Refrigerant maldistribution in refrigerant system evaporators is a well-known phenomenon. It causes significant evaporator and overall system performance degradation over a wide range of operating conditions. Maldistribution of refrigerant may occur due to differences in flow impedances within evaporator channels, non-uniform airflow distribution over external heat transfer surfaces, improper heat exchanger orientation or poor manifold and distribution system design. Maldistribution is particularly pronounced in parallel flow evaporators due to their specific design with respect to refrigerant routing to each refrigerant circuit. Attempts to eliminate or reduce the effects of this phenomenon on the performance of parallel flow evaporators have been made with little or no success. The primary reasons for such failures have generally been related to complexity and inefficiency of the proposed technique or prohibitively high cost of the solution.
[0005] In recent years, parallel flow heat exchangers, and furnace-brazed aluminum heat exchangers in particular, have received much attention and interest, not just in the automotive field but also in the heating, ventilation, air conditioning and refrigeration (HVAC&R) industry. The primary reasons for the employment of the parallel flow technology are related to its superior performance, high degree of compactness and enhanced resistance to corrosion. Parallel flow heat exchangers are now utilized in both condenser and evaporator applications for multiple products and system designs and configurations. The evaporator applications, although promising greater benefits and rewards, are more challenging and problematic. Refrigerant maldistribution is one of the primary concerns and obstacles for the implementation of this technology in the evaporator applications.
[0006] As known, refrigerant maldistribution in parallel flow heat exchangers occurs because of unequal pressure drop inside the channels and in the inlet and outlet manifolds, as well as poor manifold and distribution system design. In the manifolds, the difference in length of refrigerant paths, phase separation and gravity are the primary factors responsible for maldistribution. Inside the heat exchanger channels, variations in the heat transfer rate, airflow distribution, manufacturing tolerances, and gravity are the dominant factors. Furthermore, the recent trend of the heat exchanger performance enhancement promoted miniaturization of its channels (so-called minichannels and microchannels), which in turn negatively impacted refrigerant distribution. Since it is extremely difficult to control all these factors, many of the previous attempts to manage refrigerant distribution, especially in parallel flow evaporators, have failed.
[0007] In the refrigerant systems utilizing parallel flow heat exchangers, the inlet and outlet manifolds or headers (these terms will be used interchangeably throughout the text) usually have a conventional cylindrical shape. When the two-phase flow enters the header, the vapor phase is usually separated from the liquid phase. Since both phases flow independently, refrigerant maldistribution tends to occur.
[0008] If the two-phase flow enters the inlet manifold at a relatively high velocity, the liquid phase (droplets of liquid) is carried by the momentum of the flow further away from the manifold entrance to the remote portion of the header. Hence, the channels closest to the manifold entrance receive predominantly the vapor phase and the channels remote from the manifold entrance receive mostly the liquid phase. If, on the other hand, the velocity of the two-phase flow entering the manifold is low, there is not enough momentum to carry the liquid phase along the header. As a result, the liquid phase enters the channels closest to the inlet and the vapor phase proceeds to the most remote ones. Also, the liquid and vapor phases in the inlet manifold can be separated by the gravity forces, causing similar maldistribution consequences. In either case, maldistribution phenomenon quickly surfaces and manifests itself in evaporator and overall system performance degradation.
[0009] Moreover, maldistribution phenomenon may cause the two-phase (zero superheat) conditions at the exit of some channels, promoting potential flooding at the compressor suction that may quickly translate into the compressor damage.
SUMMARY OF THE INVENTION
[0010] It is therefore an object of the present invention to provide for a system and method which overcomes the problems of the prior art described above.
[0011] The objective of the invention is to introduce a pressure drop control for the parallel flow evaporator that will essentially equalize pressure drop through the heat exchanger channels and therefore eliminate refrigerant maldistribution and the problems associated with it. Further, it is the objective of the present invention to provide refrigerant expansion at the entrance of each channel, thus eliminating a predominantly two-phase flow in the inlet manifold and preventing phase separation, which is one of the main causes for refrigerant maldistribution.
[0012] In accordance with the present invention, each of the channels is crimped at or adjacent to their entrance location such that a desired restriction for each of the channels is provided. The restriction size may be varied from channel to channel, if desired, in order to accommodate other non-uniform factors (such as different heat transfer rates) affecting the maldistribution phenomenon. The channels may be crimped at the very end/entrance or some distance away from the entrance in order not to interfere with the brazing joint to the inlet manifold. Additionally, internal rigidity (and/or heat transfer enhancement) fins can be simply compressed during crimping process or machined down prior to crimping. Furthermore, these restrictions can be used as primary (and the only) expansion devices for low-cost applications or as secondary expansion devices, in case precise superheat control is required, and another fixed area restriction device (such as a capillary tube or an orifice) or a thermostatic expansion valve (TXV) or an electronic expansion valve (EXV) is employed as a primary expansion device. Also, the precision of crimping doesn't have to be of extremely high tolerance in a latter case.
[0013] In both cases outlined above, but especially if the crimping restrictions are provided as primary expansion devices at the entrance of each channel of the parallel flow evaporator, they represent a major resistance to the refrigerant flow within the evaporator. In such circumstances, the main pressure drop region will be across these restrictions and the variations in the pressure drop in the channels or in the manifolds of the parallel flow evaporators will play a minor (insignificant) role. Further, since refrigerant expansion is taking place at the entrance of each channel, a predominantly single-phase liquid refrigerant is flown through the inlet manifold and no phase separation occurs prior to entering individual evaporator channels. Hence, uniform refrigerant distribution is achieved, evaporator and system performance is enhanced, flooding conditions at the compressor suction are avoided and, at the same time, precise superheat control is not lost (whenever required). Furthermore, low extra cost for the proposed method makes this invention very attractive.
[0014] Any suitable means of crimping may be employed such as a crimping tool in the form of pliers having the desired crimping face geometry or the use of stamping die having the desired geometry.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] For a further understanding of the objects of the invention, reference will be made to the following detailed description of the invention which is to be read in connection with the accompanying drawing, where:
[0016] FIG. 1 is a schematic illustration of a parallel flow heat exchanger in accordance with the prior art.
[0017] FIG. 2 is an enlarged partial side sectional view of a parallel flow heat exchanger illustrating one embodiment of the present invention.
[0018] FIG. 3 a is a view of FIG. 2 illustrating a second embodiment of the present invention.
[0019] FIG. 3 b is a view of FIG. 2 illustrating a third embodiment of the present invention.
[0020] FIG. 3 c is a view of FIG. 2 illustrating a fourth embodiment of the present invention.
[0021] FIG. 3 d is a view of FIG. 2 illustrating a fifth embodiment of the present invention.
[0022] FIG. 4 is an end view of an uncrimped channel.
[0023] FIG. 5 is a view of FIG. 4 after crimping to a predetermined configuration.
[0024] FIG. 6 is a view of FIG. 4 after crimping to a second configuration.
[0025] FIG. 7 is an end view of a second uncrimped channel.
[0026] FIG. 8 is a view of FIG. 7 after crimping to a predetermined configuration.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0027] Referring now to FIG. 1 , a parallel flow (minichannel or microchannel) heat exchanger 10 is shown which includes an inlet header or manifold 12 , an outlet header or manifold 14 and a plurality of parallel disposed channels 16 fluidly interconnecting the inlet manifold 12 to the outlet manifold 14 . Typically, the inlet and outlet headers 12 and 14 are cylindrical in shape, and the channels 16 are tubes (or extrusions) of flattened or round cross-section. Channels 16 normally have a plurality of internal and external heat transfer enhancement elements, such as fins. For instance, external fins 18 , uniformly disposed therebetween for the enhancement of the heat exchange process and structural rigidity are typically furnace-brazed. Channels 16 may have internal heat transfer enhancements and structural elements as well (See FIGS. 4-6 ).
[0028] In operation, refrigerant flows into the inlet opening 20 and into the internal cavity 22 of the inlet header 12 . From the internal cavity 22 , the refrigerant, in the form of a liquid, a vapor or a mixture of liquid and vapor (the most typical scenario in the case of an evaporator with an expansion device located upstream) enters the channel openings 24 to pass through the channels 16 to the internal cavity 26 of the outlet header 14 . From there, the refrigerant, which is now usually in the form of a vapor, in the case of evaporator applications, flows out of the outlet opening 28 and then to the compressor (not shown). Externally to the channels 16 , air is circulated preferably uniformly over the channels 16 and associated fins 18 by an air-moving device, such as fan (not shown), so that heat transfer interaction occurs between the air flowing outside the channels and refrigerant within the channels.
[0029] According to one embodiment of the invention, as illustrated in FIG. 2 , the channels 16 have been crimped at least at the entrance end 30 to provide for a restriction in each channel and to assure refrigerant expansion directly at each channel entrance which results in a pressure drop across the restriction and reduction and/or elimination of phase separation and refrigerant maldistribution in the system.
[0030] In a second embodiment of the invention, as illustrated in FIG. 3 a , the channels are crimped at the very end 32 and at a point 34 , some distance away from the end and the attachment point to the manifold 12 .
[0031] In a third embodiment, as illustrated in FIG. 3 b , the channels are crimped at a single location 36 , a predetermined distance from the channel end and, once again, away form the attachment point to the manifold 12 , in order not to interfere with the attachment process.
[0032] In a fourth embodiment, as illustrated in FIG. 3 c , the channels are crimped for a predetermined length or distance “L” near the channel ends but with less cross-section area alteration/reduction than in FIGS. 2 , 3 a and 3 b.
[0033] In a fifth embodiment of the invention, as illustrated in FIG. 3 d , the channels are crimped at multiple locations 38 , 40 and 42 near the channel ends, forming a passage of alternating contractions and expansions, but, once again, with less cross-section area alteration/reduction than in FIGS. 2 , 3 a and 3 b.
[0034] FIG. 4 illustrates a cross section of an uncrimped channel 50 having flattened shape and integral vertical support members 52 .
[0035] FIG. 5 illustrates channel 50 crimped to a predetermined configuration 60 which would be suitable for use in the present invention. In this case, crimping occurs around support members 52 and leaves them unaltered.
[0036] FIG. 6 illustrates channel 50 crimped to a more flattened configuration 70 which would also be suitable for use in the present invention. In this case, crimping occurs uniformly and alters support members 52 to a different shape and cross-section 72 . Obviously, different support members can be utilized within the scope of the present invention to divide channels 16 internally into multiple refrigerant passes of triangular, trapezoidal, circular or any other suitable cross-section. In all these cases, support members can be altered during the crimping process or left unchanged.
[0037] FIG. 7 illustrates a cross section of an uncrimped channel 80 of a flattened shape (no internal support members are present in this design configuration).
[0038] FIG. 8 illustrates channel 80 crimped to a more flattened configuration 90 suitable for use in the present invention.
[0039] Also, it has to be noted that crimping doesn't have to be uniform throughout all the channels but instead can progressively change from one channel to another or from one channel section to another, for instance, to counter-balance other factors effecting refrigerant maldistribution.
[0040] Further, it has to be noted that the crimping can be used in the condenser and evaporator applications at the channel entrance within intermediate manifolds as well. For instance, if a heat exchanger has more than one refrigerant pass, an intermediate manifold (between inlet and outlet manifolds) is incorporated in the heat exchanger design. In the intermediate manifold, refrigerant is typically flown in a two-phase state, and such heat exchanger configurations can similarly benefit from the present invention by incorporating channel crimping at the entrance ends directly communicating with intermediate manifolds. Further, the crimping can be done at the exit end of the channels 16 or at some intermediate location along the channel length providing only hydraulic resistance uniformity and pressure drop control and with less effect on overall heat exchanger performance.
[0041] Since, for particular applications, the various factors that cause the maldistribution of refrigerant to the channels are generally known at the design stage, the inventors have found it feasible to introduce the design features that will counter-balance them in order to eliminate the detrimental effects on the evaporator and overall system performance as well as potential compressor flooding and damage. For instance, in many cases it is generally known whether the refrigerant flows into the inlet manifold at a high or low velocity and how the maldistribution phenomenon is affected by the velocity values. A person of ordinarily skill in the art will recognize how to apply the teachings of this invention to other system characteristics.
[0042] While the present invention has been particularly shown and described with reference to the preferred embodiments as illustrated in the drawing, it will be understood by one skilled in the art that various changes in detail may be effected therein without departing from the spirit and scope of the invention as defined by the claims. | A parallel flow (minichannel or microchannel) evaporator includes channels which are crimped at or adjacent to their entrance location which provides for a refrigerant expansion and pressure drop control resulting in the elimination of refrigerant maldistribution in the evaporator and prevention of potential compressor flooding. Progressive crimping to counter-balance factors effecting refrigerant distribution is also disclosed. | 5 |
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"BACKGROUND OF THE INVENTION \n 1. Field to which Invention Relates \n The invention relates(...TRUNCATED) | "A table is adapted to receive the shrunk foil package, and its top is substantially the same in siz(...TRUNCATED) | 1 |
"CROSS REFERENCE TO RELATED APPLICATION \n [0001] This application is a continuation under (...TRUNCATED) | "A lock system includes keys, key blanks, keyways, and lock cylinders, and the keys or key blanks ha(...TRUNCATED) | 8 |
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