1. Field of the Invention
The present invention relates generally to the field of targets, and more specifically, to human and vehicle targets constructed with a thermal imaging system.
2. Description of the Related Art
Infrared and other thermal-related detection devices have become increasingly important, particularly in combat. This technology has not been effectively deployed, however, for the purpose of assisting soldiers in distinguishing friendly soldiers from enemy combatants. One of the challenges facing soldiers in the field who employ heat detection devices such as infrared detectors is that the identity of a target is not readily discernible based on the mere existence of a heat signature. For example, animals, vehicles and random mechanical devices may all emit heat and, therefore, present themselves as a potential target. Without the right kind of target, heat detection device cannot differentiate between humans and other animals or things that emit heat.
A human body emits various levels of heat depending on the area of the body. For example, the top of the head emits less heat than the armpit region, and the chest area generally emits less heat than the top of the head but more heat than the armpit region. These variations in temperature can make the heat signature difficult to replicate in a target. In addition, heat signatures vary according to the ambient temperature. Although one would expect more heat to be emitted in higher ambient temperatures, certain regions of the body emit a disproportionately high amount of heat in higher temperatures. Accordingly, a human heat signature in one ambient temperature may vary significantly from an emitted heat signature in another temperature.
Although it is beneficial to train soldiers to detect human versus non-human heat signatures and to detect human heat signatures in various ambient temperatures, it is also critically important to train soldiers in differentiating one human heat signature from another. When a human is holding or carrying a weapon or other equipment, the resulting heat signature is characterized by a “cold spot” in the image corresponding to the location at which the body heat is blocked by the equipment. This characteristic in the heat signature is useful in identifying friendly versus enemy soldiers where the object causing the heat interference is specific to either the friendly or enemy soldier. For example, a soldier carrying an AK-47 or rocket-propelled grenade may be differentiated from U.S. or NATO soldiers who carry different weaponry and equipment. It is also important to train soldiers to distinguish different types of vehicles based on their heat signatures.
Accordingly, it is an object of the present invention to provide a target with a thermal imaging system that emulates a human or vehicle heat signature by allowing for different heat output in different heating zones. It is a further object of the present invention to provide a thermal imaging system in which the thermal output can be varied to accommodate different ambient temperatures. Lastly, it is an object of the present invention to provide a thermal imaging system that can be shot at numerous times and still continue to function. The present invention meets each of these objectives, as described more fully below.
The present invention is a target with a thermal imaging system comprising a layer of corrugated plastic; a layer of bifurcated metallic foil; a layer of plastic; a wire grid; two strips of carbon tape; a front cover sheet; and a power lead with two first ends and a second end; wherein the layer of bifurcated metallic foil is situated on top of the layer of corrugated plastic; wherein the layer of plastic is situated on top of the layer of bifurcated metallic foil; wherein the wire grid is situated on top of the layer of plastic and comprises a right side and a left side; wherein one strip of carbon tape is adhered to the right side of the wire grid, and the other strip of carbon tape is adhered to the left side of the wire grid; wherein the front cover sheet is adhered to the target so that it covers the wire grid and carbon tape; and wherein the power lead comprises two first ends and a second end, each of the strips of carbon tape comprises a first end, one of the first ends of the power lead is connected to the first end of one of the carbon strips, the other first end of the power lead is connected to the first end of the other carbon strip, and the second end of the power lead is a connector plug. In an alternate embodiment, the first ends of the power lead are crimped directly to the bifurcated metallic foil.
In a preferred embodiment, the first ends of the power lead ate comprised of tin, each first end of the power lead comprises teeth, and the teeth punch through the carbon tape and the layer of metallic foil when the first end of the power lead is connected to the first end of the carbon strip.
In a preferred embodiment, the present invention further comprises a hard plastic backing that is fastened to the corrugated plastic layer and that is used to secure the target in a target lift device. Preferably, the hard plastic backing is fastened to the corrugated plastic layer in a manner that allows the target to be bent vertically to fit into a target lift device. The layer of corrugated plastic preferably comprises an uppermost edge, and wherein a layer of caulk is applied to the uppermost edge of the layer of corrugated plastic.
In a preferred embodiment, the wire grid comprises a plurality of horizontal wires and a plurality of vertical wires, each horizontal wire comprises a first end and a second end, the first end of each horizontal wire comes into contact with one of the strips of carbon tape, the second end of each horizontal wire comes into contact with the other strip of carbon tape, and none of the vertical wires comes into contact with either of the strips of carbon tape. Preferably, the vertical wires are positioned on top of the horizontal wires. The vertical wires are preferably approximately one-half inch apart, and the vertical wires are preferably approximately one inch apart.
In a preferred embodiment, the wire grid is constructed so as to provide different heating zones within the target. Preferably, the different heating zones comprise a head zone, a shoulder zone, and a body zone, the wire grid comprises a plurality of horizontal wires and a plurality of vertical wires, each horizontal wire has a diameter, and the diameter of the horizontal wires differs among the heating zones. Preferably, the wire grid comprises a plurality of horizontal wires and a plurality of vertical wires, the horizontal wires are comprised of a nickel and chrome alloy, each horizontal wire has a diameter, the diameter of the horizontal wires in the head zone is roughly 0.0014 inches, the diameter of the horizontal wires in the shoulder zone is roughly 0.00175 inches, and the diameter of the horizontal wires in the body zone is roughly 0.002 inches. Preferably, the wire grid comprises a plurality of horizontal wires and a plurality of vertical wires, the vertical wires are comprised of a copper and nickel alloy, each vertical wire has a diameter, and the diameter of each vertical wire is roughly 0.004 inches.
In a preferred embodiment, the wire grid comprises a plurality of horizontal wires and a plurality of vertical wires, and the target further comprises a cap zone containing no horizontal wires and into which none of the vertical wires extends. Preferably, the wire grid comprises a plurality of horizontal wires and a plurality of vertical wires, the target has a front surface, and horizontal and vertical wires together comprise less than two percent of the front surface of the target.
In a preferred embodiment, the bifurcated foil layer comprises two outer edges, the first layer of plastic prevents the vertical wires from coming into contact with the bifurcated foil layer, and the first layer of plastic prevents the horizontal wires from coming into contact with the bifurcated foil layer other than at the outer edges of the bifurcated foil layer.
The present invention optionally comprises a silhouette accessory, wherein the silhouette accessory comprises at least one thermal block with a removable strip and an outer surface comprising an adhesive layer that allows the thermal block to be adhered to the front cover sheet.
In yet another embodiment, the present invention is a target with a thermal imaging system comprising one or more sections, wherein each section of the target comprises at least one heater, and wherein each heater comprises a layer of insulating material, a layer of bifurcated metallic foil, a layer of plastic, a wire grid comprised of a plurality of horizontal elements and a plurality of vertical wires, at least two strips of carbon tape, and a front cover sheet; wherein the layer of bifurcated metallic foil is situated on top of the layer of insulating material; wherein the layer of plastic is situated on top of the layer of bifurcated metallic foil; wherein the layer of insulating material is at least as large as the layer of bifurcated metallic foil; wherein the wire grid is situated on top of the layer of plastic and comprises at least two outer edges; wherein one strip of carbon tape is adhered to one of the outer edges of the wire grid, and the other strip of carbon tape is adhered to another outer edge of the wire grid so that both strips of carbon tape come into contact with the horizontal elements but not with the vertical wires; wherein the front cover sheet is adhered to the heater so that it covers the wire grid and carbon tape; and wherein the front cover sheet comprises an image of a side view, front view or rear view of a vehicle. Preferably, each section has an outline, when the target is assembled, the outlines of the sections form a single, combined outline, and the single, combined outline is an outline of a vehicle.
In a preferred embodiment, the present invention further comprises a power lead with two first ends, and each first end of the power lead is attached to one of the strips of carbon tape. In an alternate embodiment, the present invention further comprises a power lead with two first ends, the layer of bifurcated metallic foil comprises two halves, and each first end of the power lead is attached directly to one half of the layer of bifurcated metallic foil. Preferably, the first ends of the power lead are comprised of tin.
In a preferred embodiment, the sections of the target are affixed to a rigid backing. Optionally, the rigid backing is attached to a target lift device.
In a preferred embodiment, the layer of insulating material is polycarbonate film. Preferably, each horizontal element is comprised of multiple wires spun around a fiberglass strand. The vertical wires are preferably positioned on top of the horizontal elements.
In a preferred embodiment, the layer of bifurcated metallic foil is comprised of aluminum. In one embodiment, the layer of bifurcated metallic foil comprises one or more flaps that fold around behind the layer of insulating material. The layer of plastic is preferably transparent.
In a preferred embodiment, the bifurcated foil layer has one or more outer edges, the layer of plastic prevents the vertical wires from coming into contact with the bifurcated foil layer, and the layer of plastic prevents the horizontal elements from coming into contact with the bifurcated foil layer other than at the outer edges of the bifurcated foil layer. Preferably, the front cover sheet is comprised of vinyl with an adhesive backing.
In a preferred embodiment, each heater is comprised of one or more heating zones, and each heating zone generates a particular wattage that is different than the wattage of the other heating zones within the same heater. Preferably, the horizontal elements are located within a heating zone, and the horizontal elements are spaced from one another within the heating zone so as to generated a desired wattage within the heating zone within which the horizontal elements are located. The front cover sheet is preferably a single front cover sheet that covers all of the sections of the target.
In one embodiment, the present invention comprises an overlay; each section of the target has a front surface; the overlay is comprised of a layer of corrugated plastic, one or more thermal blocks comprised of corrugated plastic, and a front cover sheet; the front cover sheet is adhered to a front surface of the corrugated plastic layer, and the thermal block(s) is/are adhered to a rear surface of the corrugated plastic layer; and the thermal block(s) is/are adhered to the front surface of one of the sections of the target. In an alternate embodiment, the present invention further comprises an overlay; each section of the target has a front surface; the overlay is comprised of a layer of polycarbonate film, at least one stand-off comprised of at least one strip of polycarbonate film, and a front cover sheet; the front cover sheet is adhered to a front surface of the polycarbonate film layer, and the stand-off(s) is/are adhered to a rear surface of the polycarbonate film layer; and the stand-off(s) is/are are adhered to the front surface of one of the sections of the target.
1 Hard plastic backing
2 Corrugated plastic layer
3 Bifurcated foil layer
4 First layer of clear plastic
5 Wire grid
6 Carbon tape
7 Second layer of clear plastic
8 Front cover sheet
9 Silhouette accessory
10 Cut-out (in hard plastic backing)
11 Aperture (in hard plastic backing)
12 Aperture (in corrugated plastic layer)
13 Cut-out (in corrugated plastic layer) for rivet
14 Cut-out (in corrugated plastic layer) for second end of power lead
15 Aperture (in bifurcated aluminum layer)
16 Aperture (in first clear plastic layer)
17 Horizontal wire
18 Vertical wire
19 Head zone
20 Body zone
21 Shoulder zone
22 Cap zone
23 First end of power lead
24 Second end of power lead
25 First rivet
26 Spacer component
27 Second rivet
28 Rivet backing
29 Silhouette accessory
30 Thermal block
31 Removable strip
32 Outer adhesive surface (of thermal block)
33 Power lead
34 First part (of vehicle target)
35 Second part (of vehicle target)
36 Third part (of vehicle target)
37 Fourth part (of vehicle target)
38 Fifth part (of vehicle target)
39 Sixth part (of vehicle target)
40 Seventh part (of vehicle target)
41 First vehicle overlay
42 Second vehicle overlay
43 Third vehicle overlay
44 Vehicle nose piece
45 Rigid backing
46 Polycarbonate film layer (of vehicle target heater)
47 Bifurcated foil layer (of vehicle target heater)
48 Plastic layer (of vehicle target heater)
49 Wire grid (of vehicle target heater)
50 Carbon tape (of vehicle target heater)
51 Front cover sheet (of vehicle target heater)
52 Foil flap
53 First heater (of first part of vehicle target)
54 Second heater (of first part of vehicle target)
55 Cut-out (in front cover sheet of first part of vehicle target)
56 Gap
57 Portion of first part
58 First heating zone (of second part)
59 Second heating zone (of second part)
60 Third heating zone (of second part)
61 First heating zone (of third part)
62 Second heating zone (of third part)
63 Third heating zone (of third part)
64 First heating zone (of fourth part)
65 Second heating zone (of fourth part)
66 Third heating zone (of fourth part)
67 First heating zone (of fifth part)
68 Second heating zone (of fifth part)
69 Third heating zone (of fifth part)
70 Non-heating zone (of fifth part)
71 Door area
72 First heating zone (of sixth part)
73 Second heating zone (of sixth part)
74 Third heating zone (of sixth part)
75 First heating zone (of seventh part)
76 Second heating zone (of seventh part)
77 Polycarbonate film layer (of vehicle overlay)
78 Front cover sheet (of vehicle overlay)
79 Polycarbonate film strip (of vehicle overlay)
80 Layer of corrugated plastic (of vehicle overlay)
81 Thermal block (of vehicle overlay)
82 Removable strip (of vehicle overlay)
83 Outer adhesive surface (of thermal block)
84 Polycarbonate film layer (of nose piece)
85 Front cover sheet (of nose piece)
86 Polycarbonate film layer (of wheel embodiment)
The hard plastic backing 1 is used to secure the target in a target lift device, such as those currently in use by the military. In a preferred embodiment, the hard plastic backing 1 also provides sufficient mechanical resistance so that when the target is hit (shot at), the target lifter will cause the target to fall down. Without a backing made of hard plastic or similarly mechanically resistant material, the target will heat as intended, but it will not fall down when hit. Thus, although some type of backing is needed to secure the target to the target lift device, a hard plastic backing 1 is preferred for those applications in which it is important to cause the target to fall down when hit.
The hard plastic backing 1 preferably comprises one or more cut-outs 10 that allow the hard plastic backing 1 to be secured to a target lift device. The exact size and shape of these cut-outs 10 will depend on the target lift device to which the hard plastic backing 1 is secured. Some target device may not require any cut-outs at all. The present invention is not limited to any particular shape, size or number of cut-outs 10, or any cut-outs at all, in the hard plastic backing 1. The hard plastic backing 1 also comprises a plurality of apertures 11 that are used to secure the hard plastic backing 1 to the corrugated plastic layer 2, as described more fully below.
The corrugated plastic layer 2 is a non-conductive layer that serves as the template upon which the wire grid 5 is supported. As shown in
All of the layers shown in
The bifurcated foil layer 3 is electrically conductive, and it is bifurcated to prevent short circuits from occurring when the wire grid 5 is energized. The bifurcated foil layer 3 is preferably slightly shorter and narrower than the corrugated plastic layer 2. The bifurcated foil layer 3 also comprises apertures 15 for securing the corrugated plastic layer 2 (and the other layers that rest on top of it, namely, the bifurcated foil layer 3, the first clear plastic layer 4, the wire grid 5, and the carbon tape 6) to the hard plastic backing 1. The bifurcated foil layer 3 preferably comprises an adhesive on either side (back and front) so as to facilitate adhesion to the corrugated plastic layer 2 and the first clear plastic layer 4.
The next layer after the bifurcated foil layer 3 is the first clear plastic layer 4. This layer is roughly the same size as the bifurcated foil layer 3, except that it is not bifurcated. The first clear plastic layer 4 is preferably the same length as the bifurcated foil layer 2 but slightly narrower than the bifurcated foil layer 2. The purpose of the first clear plastic layer is to prevent the wire grid 5 from touching the bifurcated foil layer 3 other than at the outer vertical edges of the bifurcated foil layer 3. The first clear plastic layer 4 preferably comprises an adhesive on both sides (back and front) so as to facilitate adhesion of the first clear plastic layer 4 to the bifurcated foil layer 3 and the wire grid 5 to the first clear plastic layer 4. The first clear plastic layer 4 comprises apertures 16 that are used to secure the corrugated plastic layer (and the other layers on top of it) to the hard plastic backing 1.
The next layer is the wire grid 5. This layer comprises a plurality of horizontal wires 17 and a plurality of vertical wires 18. The horizontal wires 17 extend beyond the edge of the first clear plastic layer 4 so that they come into contact with the bifurcated foil layer 3. The vertical wires 18 end short of the clear plastic layer 4 so that they do not come into contact with the bifurcated foil layer 3 at all. As discussed more fully below, the purpose of the wire grid 5 is to conduct electricity across the surface of the target when the carbon tape 6 is energized.
The carbon tape 6 preferably runs from the bottom of the target to the top, along the outer edges of the target. As discussed in connection with
In a preferred embodiment, the corrugated plastic layer 2 is secured to the hard plastic backing 1 with rivets (see
The next layer is the front cover sheet 8. The front cover sheet 8 is preferably comprised of vinyl with an adhesive on one side that allows the front cover sheet 8 to be adhered to the assembly (the “assembly” being the corrugated plastic layer 2, the bifurcated foil layer 3, the first clear plastic layer 4, the wire grid 5, and the carbon tape 6 but excluding the second clear plastic layer 7). The front cover sheet 8 may comprise an image of a friendly soldier, an enemy combatant, or it may be a solid color. The front cover sheet 8 allows the target to be used to provide an image for visual non-assisted (non-thermal) identification.
An optional silhouette accessory 9 may be adhered to the front cover sheet 8 (see
In a preferred embodiment, the wire grid 5 is constructed so as to provide different heating zones within the target. As is known in the art, the electrical resistance of a wire is affected by the wire's diameter, length, and the type of metal or metal alloy used to fabricate the wire. In the present invention, the length of horizontal wire 17 is dictated by the shape of the target. The diameter, however, can be adjusted. In a preferred embodiment, the wire grid 5 comprises a head zone 19, a body zone 20, and a shoulder zone 21. In a preferred embodiment, the target further comprises a cap zone 22 that contains no horizontal wires and to which none of the vertical wires extends.
In a preferred embodiment, all of the horizontal wires 17 are preferably comprised of the same metal alloy, namely, an alloy of nickel and chrome. One such alloy is NIKROTHAL 60™ manufactured by Sandvik AB of Sandviken, Sweden. In a preferred embodiment, the horizontal wires of the head zone 20 are 47 gauge (0.0014 inches in diameter), the horizontal wires of the shoulder zone 22 are 45 gauge (0.00175 inches in diameter), and the horizontal wires of the body zone 21 are 44 gauge (0.002 inches in diameter). By adjusting the diameter of the wires in the head, shoulder and body zones in relation to the length of the wires, a target is provided that will emit greater heat in the head area, less heat in the body area, and still less heat in the shoulder area. No heat is emitted in the cap area.
The vertical wires 18 preferably have a greater diameter than all of the horizontal wires 17 so that they will conduct electricity without heating up (i.e., they are preferably less resistant than the horizontal wires 17). In a preferred embodiment, the vertical wires 18 are 38 gauge (0.004 inches in diameter), and they are comprised of an alloy of copper and nickel. One such alloy is CUPROTHAL 49™ manufactured by Sandvik AB of Sandviken, Sweden. The vertical wires are not connected to a power source, and their only function is to provide a path around a broken horizontal wire.
In a preferred embodiment, the wires 17, 18 that comprise the wire grid 5 comprise less than two percent (2%) of the entire front surface of the target. The wire grid 5 is constructed to provide maximum survivability to the target. In tests involving the present invention, the target was hit by 1600 bullets and still continued functioning. The reason the target is able to survive this many hits is because if a horizontal wire is broken, the electrical current may travel up one of the vertical wires and across an adjacent horizontal wire. The only way the target would become completely dysfunctional is if all (or a significant portion) of the horizontal wires were broken at the point at which they cross from one half of the bifurcated foil layer 3 to the other. The odds of that happening are virtually nil.
The first end 23 of the power lead 33 is preferably comprised of tin so that it will not react with the aluminum foil. The first end 23 preferably comprises teeth (shown in
Second rivets 27 and rivet backings 28 are used to secure the plastic corrugated layer 2 to the hard plastic backing 1 at apertures 11, 12, 15 and 16. As shown in
As shown in
The purpose of the vehicle heater of the present invention is to emulate the heat signature of a particular vehicle. Thus, a series of individual heaters, each comprising a plurality of vertical and horizontal wires as in the human target described above, is affixed to a backing of plywood or other suitable rigid material in the shape of whichever view (side, front, rear, etc.) is being emulated. This rigid backing 45 is shown in
The vehicle target heaters differ from the human target heaters described above in that they do not incorporate a hard plastic backing 1, nor do they have a corrugated plastic layer 2. Instead of the corrugated plastic layer 2, each vehicle target heater comprises a layer of insulating material, preferably polycarbonate film 46. In a preferred embodiment, the polycarbonate film is LEXAN™ brand manufactured by SABIC Innovative Plastics IP B.V. Company of Bergen OP Zoom, Netherlands. Next are a layer of bifurcated metallic foil 47, preferably aluminum, a layer of plastic 48, preferably but not necessarily clear (transparent), the wire grid 49, carbon tape 50, and a front cover sheet 51 that serves as a graphic overlay.
In this example, there could be separate front cover sheets 51 for each of the parts of the vehicle target, or there could be a single graphic overlay 51 that lies across the entire span of the vehicle target shown in
The polycarbonate film 46 serves the same purpose as the corrugated plastic layer 2 of the human targets, that is, it acts as an insulating layer. Polycarbonate film 46 is preferred for the vehicle targets due to weight restrictions.
The bifurcated foil layer 47 serves the same purpose as the bifurcated foil layer of the human targets, that is, it acts to conduct (or spread) the heat conveyed by the horizontal and vertical wires of the wire grid 49. As in the human targets, the plastic layer 48 is smaller (narrower and/or shorter, depending on the configuration of the vehicle heater involved) than the bifurcated foil layer 47 to allow the horizontal wires of the wire grid 49 to come into contact with the foil only at the outer edges of the foil layer where there is carbon tape 50. Preferably, the vertical wires never touch the carbon tape and do not come into contact with the foil layer at all.
The wire grid 49 of each vehicle target heater comprises a plurality of horizontal and vertical wires (or elements); however, as shown in subsequent figures, the horizontal wires may be slanted or angled to accommodate to accommodate different shapes of heaters. The vertical wires are all preferably a constant distance apart; in the examples shown in the figures, the vertical wires are all 2.0 inches apart. The spacing between horizontal wires is determined so as to generate the desired wattage within the heating zone at issue. In addition, each horizontal element may actually be comprised of multiple wires spun around a fiberglass strand to achieve a desired resistance per foot that best achieves a given power density for a particular area. As used herein (with respect to both the vehicle targets and the human targets), the term “horizontal wire” may also be a “horizontal element” comprised of more than one wire.
During the manufacturing, handling and storage process, a second clear plastic layer (not shown) may be used, as described above in connection with the human targets (reference number 7). This layer is not shown in the vehicle target figures, however, because it is not part of the final assembly.
In the case of the second 35, third 36, fourth 37, fifth 38, sixth 39 and seventh 40 parts of the vehicle target, the polycarbonate film 34, bifurcated foil 35 and front cover sheet 51 are all the same size (that is, unless a larger front cover sheet 51 is used to cover more than one vehicle part). As noted above, the plastic layer 48 is preferably smaller in size than these three layers. In the example provided in the figures, the polycarbonate and foil layers of the first part 34 are significantly larger than the other layers, however, because the first part 34 comprises two separate heaters (see
The present invention is not limited to any particular number, shape, size or configuration or vehicle overlay, and it includes a target with no vehicle overlays at all. The vehicle overlays illustrated in the figures are meant to serve as examples of the types of vehicle overlays that may be used.
In this embodiment, the two layers of polycarbonate film are situated side-by-side, and they are the same size as the bifurcated foil layer (in other words, one layer of polycarbonate film corresponds to each side of the bifurcated foil layer), except that each half of the bifurcated foil layer comprises a flap (not shown) that folds around the polycarbonate layer 86 and lies underneath the carbon tape 50. The ends of the horizontal wires of the wire grid 49 wrap around the plastic layer, the bifurcated foil layer, and the layer of polycarbonate film so that they lie directly underneath the carbon tape 50 and on top of the foil flaps.
This configuration enables an electrical connection to be made between the carbon tape, the ends of the horizontal wires, and the foil. With the exception of the ends of the horizontal wires (not shown) that lie underneath the carbon tape, the wire grid 49 shown in
A significant advantage of the vehicle target heater described above is the fact that it comprises multiple modular sections or parts, each of which comprises one or two heaters in the example provided. This modular design allows for partial replacement of a part or a heater within a part without the entire vehicle target having to be replaced. Due to the unique heater design, and more specifically, the configuration of the horizontal and vertical wires (or elements), each section or part of the vehicle target can withstand multiple hits by a projectile and continue to provide an accurate heat pattern for the vehicle.
Although the preferred embodiment of the present invention has been shown and described, it will be apparent to those skilled in the art that many changes and modifications may be made without departing from the invention in its broader aspects. The appended claims are therefore intended to cover all such changes and modifications as fall within the true spirit and scope of the invention.
This application is a continuation-in-part of U.S. patent application Ser. No. 12/467,780 filed on May 18, 2009, which is a continuation-in-part of U.S. patent application Ser. No. 12/052,792 filed on Mar. 21, 2008. The contents of these applications are incorporated herein by reference.
Number | Date | Country | |
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Parent | 12467780 | May 2009 | US |
Child | 12500601 | US | |
Parent | 12052792 | Mar 2008 | US |
Child | 12467780 | US |