Patent Application
20120175522
This invention relates to signage for infrared imaging techniques. In particular, the present invention relates to articles of manufacture useful as signage or identifiers of objects using infrared radiation, the method of preparing the articles and the method of using the articles to target and calibrate infrared weapon sights. The invention is particularly useful in the field of firearms.
Infrared cameras permit weapon users, such as military and police personnel, to view heat sources, such as people, in complete darkness. However, infrared imaging technology has heretofore been incapable of differentiating words or symbols. To convey information, infrared imaging techniques typically have required the use of heated objects, such as exothermic chemical heaters. However, such technologies only create a point in the imaging system, thereby limiting the ability to convey complex information.
In particular, infrared weapon sights such as the TWS (Thermal Weapon Sight) from BAE, DRS Technologies, or Raytheon must be calibrated to ensure hitting a designated target. This is very important whenever the sight has been disturbed in any way. Using traditional iron sights, the user fires groups of shots at the center of a target similar to the target shown in
Attempts have been made to overcome infrared sighting problems. For example, Migliorini (U.S. Pat. No. 6,337,475) proposes using a small electrically heated silhouette placed on the front of a standard 25 meter zeroing target. This device requires a battery for operation, which poses certain logistical problems and may increase costs. Further, heat leakage from the silhouette can result in lower accuracy.
Boyer (U.S. Pat. No. 7,528,397) discloses an infrared sight calibration device that comprises an industry standard thermal infrared reflective film characterized by simple reflection. As shown in
Others proposed devices, methods, and means for sighting of infrared optical devices include those described in U.S. Pat. No. 6,767,015, which discloses a thermal target; U.S. Pat. No. 6,051,840, which discloses an infrared heat emitting device; U.S. Pat. No. 6,020,040, which discloses a thermal pack having a plurality of individual heat cells; and U.S. Pat. No. 5,918,590, which discloses heat cells.
Consequently, there remains a need for improved signage or markers for detecting infrared radiation, which overcome sighting problems previously associated with infrared imaging techniques.
A physical object which is useful as a visible detector or signage of infrared radiation has been developed. In general, the signage device of the invention comprises a laminar member having a first surface and second surface. Preferably, the laminar member comprises a multilayered structure comprising two or more materials generally capable of properly interfacing with each other and any subsequent layers adhered thereto. The second surface of the laminar member is a low emissivity surface characterized as having an emissivity value of about 0.4 or less than 0.4. Generally, the low emissivity surface comprises a surface construction such that when the laminar member is oriented vertical or substantially vertical to the earth at least a portion of the thermal energy of the sky striking the low emissivity surface is reflected away from the surface towards an observer. Preferably, thermal energy striking the low emissivity surface is reflected perpendicular or substantially perpendicular away from the surface towards an observer. Advantageously, the signage of the invention can be printed on the low emissivity surface to alter emissivity and provide a design which will be readily apparent when viewed through an infrared imaging device. Alternatively, at least a portion of the laminar member may be removed or “cutout” to alter emissivity and provides a pattern or design detectable by infrared imaging.
In a preferred embodiment of the invention, the signage of the invention is useful for targeting and calibrating an infrared scope or sight to a weapon. Preferably, the weapon is a firearm. Accordingly, the present invention also comprises a method of making a signage or object for targeting and calibrating an infrared scope to a weapon. The signage of the invention is generally prepared by forming an object that is visible when using an infrared optical device, such as an infrared camera or infrared optical sighting device for a weapon. The method of the invention provides an object that contains words, characters, graphics, and/or images that can be detected with an infrared detector, but may or may not be detectable by the naked eye. In general, the method comprises providing an object with at least one surface having a low emissivity value (i.e. an emissivity value of about 0.4 or less) and when oriented vertical or substantially vertical the earth, having the ability to reflect at least a portion of the thermal energy from the sky striking the low emissivity surface towards an observer; and modifying the surface emissive characteristic of at least a portion of the low emissivity surface by depositing on the surface one or more substances that can be detected with a device sensitive to infrared electromagnetic radiation, or by removing at least one portion of the low emissivity surface to alter emissivity.
In another embodiment of the invention, a method of calibrating an infrared weapon sight using the signage of the invention is provided. In accordance with the present invention, the method of calibrating an infrared weapon sight comprises viewing the object or signage of the invention through an infrared sight, and determining whether the sight is calibrated to the weapon, that is whether the point of impact of shots fired from the weapon corresponds to the point of aim of the sight. Optionally, where the determining step identifies an improper calibration, the method typically further comprises adjusting the sight to more accurately calibrate to the weapon. Often, the method will be practiced under controlled conditions, such as at a shooting range or on a military or police facility.
In one embodiment of the invention, at least a portion of the signage is heated to increase clarity during infrared imaging. Preferably, the heat may be applied using a chemical or an electrical heat source.
The present invention will now be described in details with reference to exemplary embodiments of the invention. The following detailed description should not be considered as a limitation on the invention, but rather should be considered as a detailed description of certain embodiments, which is presented to give those of skilled in the art a more complete understanding of the various features of the invention.
For purposes of this invention, the term “signage” is used herein to mean a sign, marker or an object, typically a laminar, which conveys some information, whether simple or complex, to an observer.
For purposes of this invention, the term “emissivity” is used herein to mean the ratio of the thermal energy radiated or emitted by a surface as compared to that radiated or emitted by a blackbody at the same temperature.
For purposes of this invention, the term “black body” is used herein to mean an object that can absorb and send off radiation with complete efficiency—that is, it reflects none of the radiation that falls on it and perfectly emits radiation as a function of temperature.
For purposes of this invention the term “substantially vertical” is used herein to mean at an angle of 30° or less of vertical and preferably at an angle of 5° or less of vertical.
For purposes of this invention the term “substantially perpendicular” is used herein to mean at an angle of 30° or less of perpendicular and preferably at an angle of 5° or less of perpendicular.
The present invention utilizes a reflective film characterized by “rotated perpendicular simple reflection”. For purposes of the present invention the term “rotated perpendicular simple reflection” is used herein to designate when a ray of energy striking the film is reflected and follows a path shown in
As shown in
The laminar member (1) may comprise one or more film layers. In a preferred embodiment, the laminar member (1) comprises multiple film or deposition layers (4), (5), and (6) as shown in
In a preferred embodiment, layer (5) comprises a sawtooth pattern etched, molded, or otherwise formed or deposited on the surface thereof. In general, any conventional tooling capable of forming the desired pattern on the surface may be used to prepare the surface of layer (5). Preferably, the tooling is a drum with a diamond etched pattern suitable to form a sawtooth pattern. While a sawtooth pattern is preferred, it will be understood by one skilled in the arts that any pattern sufficient to provide the desired thermal energy reflecting characteristics will be useful to prepare the film layer (5).
The final layer (6) is coated, deposited, or applied onto layer (5) in such a manner to conform to the surface construction of layer (5) and provide a low emissivity surface thereon, i.e. a surface having a emissivity value of about 0.4 or less. It is within the scope of the present invention that any low emissivity material capable of forming a conformable, uniform coating on the patterned surface can be used. Preferably, layer (6) comprises a shiny metal, such as for example, sputtered aluminum, gold, silver, or mixtures thereof. The low emissivity coating may be applied using conventional coating techniques such as for example, spraying, electrolysis, deposition, or sputtering.
In a most preferred embodiment of the invention, the laminar member (1) is a multilayer film currently available under the trade name, Mirage V™ from QinetiQ (UK) located in Farnborough Hampshire GU14 0LX, United Kingdom.
The emissive characteristics of the laminar member (1) may be altered by applying a printed coating (7) having a thickness and type sufficient to provide a desired emissivity value on at least one portion of the surface (3), or by removing a portion of the surface to form a cut-out shape (8) as shown in
The printed coating (7) and cutout shape (8) will typically be formed in a manner such that desired words, symbols, graphics, messages or signals are communicated. In a preferred embodiment shown in
In a second embodiment of the invention, the laminar member (1) is attached to a support (9) having a first surface and second surface (10), as shown in
The support (9) may be used in combination with a laminar member (1), preferably to provide an article wherein the thermal energy striking the low emissivity surface of the laminar member is reflected perpendicular or substantially perpendicular along a vertical axis connecting the observer and the low emissivity surface as shown in
To calibrate a weapon sight, the practitioner sets the target vertical or substantially vertical to the earth so that the sky reflects off the surface (3) and can be seen through the thermal scope by the practitioner. An appropriate number of rounds or shot groups are then fired at the center of the target. After analyzing the distance from a centroid of the shot group to the expected point of impact, the scope alignment is adjusted so that the centroid of the shot group is coincident with a predetermined location on the target.
To provide further increase clarity to the thermal weapons sight, the laminar member (1) may be completely or partially heated, as depicted in
In a preferred embodiment, a heat source is attached to the first surface of the laminar member (9). The heat source may be a chemical heater (11), such as a Toasti Toes from Heatmax, which begins to heat when exposed to oxygen in the air. The entire target or just the heater may be packaged in an air-tight package to prevent the heater from operating before use. In one embodiment, the chemical heater is completely biodegradable, which minimizes the cost and logistics of disposal. It should be noted that for this embodiment the support (9) could be omitted and the heat source applied directly to surface (2) of the laminar member.
In yet another embodiment, the heat source may be an electrical heat source such as for example, an electric heater. Preferably the electric heater begins to heat when an electric voltage is applied to it. In one embodiment, an electrical power source such as a battery may be used. Preferably, the power source has a means for preventing a current from flowing until the heat is desired, such as for example, a pull tab. In this case, when the tab is removed, the circuit is connected and current flows heating the heater. Any method preventing current flow is contemplated by the present invention.
Further, any other conventional means of providing heat to a film or film laminate is contemplated for use by the invention provided it does not interfere with the intended use of the signage device of the invention. For example, Migliorini (U.S. Pat. No. 6,337,475) discloses placing an electric heater on the second surface of a paper target, which has high or normal emissivity. The effectiveness of this is dependent on the effectiveness of the thermal insulating layer. If not completely effective, the silhouette shape will become distorted. On the other hand, the heater shape does not have to assume a specific shape for the present invention because the infrared image is created on the front surface and is a function of the cut-out shape (8) and the print coating (7) and not the geometry of the heater.
Generally, the heat source is attached to the laminar member by any conventional bonding means. Preferably, the heat source is attached to the laminar member by a bonding means which permits bonding over the entire surface of the heat source, such as for example, by using an adhesive, in particular a pressure sensitive adhesive.
In the practice of one embodiment of the invention relating to a 25 m target, the weapons user will remove the target and/or heater from its package. If a heater is used and if not already affixed to the rear of the target, the heater is affixed there and the assembly is placed on a fixture. The weapons user, or shooter, returns to the shoot position typically about twenty-five meters from the target. The chemical heater will begin to react, warming the target. When viewed through the thermal weapon sight, the aim point will be very visible. The shooter will shoot at the aim point in the center of the target. After shooting, the shooter will note the location of the rounds relative to the expected point of impact and, if needed, adjust his sights to bring the rounds to the desired point of impact.
1. The examples, which follow, are given for illustrative purposes and are not meant to limit the invention described herein.
A piece of Mirage V film (obtained from QinetiQ, United Kingdom), approximately 5″×5″, was sized to cover a grid 12 cells by 12 cells in the exact center of a larger 18 cell by 20 cell grid. A 2 cell by 2 cell section was removed from the center of the part. The part was carefully oriented such that the perpendicular from the major portion of the sawtooth profile generally pointed toward the top of the paper. This ensured that the thermal reflections would be in keeping with those described the patent. The rear of the film was coated with 3M Super 77 spray adhesive and then the film was adhered to the center of the printed grid on the ALT-C(2) M16A2 paper target. In this case the user shoots at the center of the target 3 times and adjusts their scope based on the difference between the point of aim and point of impact.
A piece of Mirage V film (from QinetiQ in the United Kingdom), approximately 5″×5″, was sized to cover a grid 12 cells by 12 cells in the exact center of the larger 18 cell by 20 cell grid. A 2 cell by 2 cell section was removed from the center of the part. The part was carefully oriented such that the perpendicular from the major portion of the sawtooth generally pointed toward the top of the paper. This ensured that the thermal reflections would be in keeping with those described the patent. The rear of the film was coated with 3M Super 77 spray adhesive and then the film was adhered to the center of the printed grid on the ALT-C(2) M16A2 paper target. A Toasti-Toes heater was placed on the rear of the target just behind the film cutout. This gave a very bright signature directly in the center of the target. In this case the user can shoot at the center of the target 3 times and adjust their scope based on the difference between the point of aim and point of impact.
A piece of Mirage V film (obtained from QinetiQ, United Kingdom), approximately 5″×5″, was sized to cover a grid 12 cells by 12 cells in the exact center of a larger 18 cell by 20 cell grid. A 2 cell by 2 cell section was removed from the center of the part. The part was carefully oriented such that the perpendicular from the major portion of the sawtooth generally pointed toward the sky. This ensured that the thermal reflections would be in keeping with those described the patent. A simple template was cut out of paper and placed in intimate contact with the film. The film was painted with the black spray paint, and the template was removed. When observed with the thermal imager the printed areas appeared warmer than the non-printed areas.
