System and methods for laser scattering, deviation and manipulation

Abstract

To provide systems and methods for scattering or deviating a laser beam.SOLUTION: A system utilizing a lenticular sheet and a laser source projecting a laser beam onto the lenticular sheet produces shapes such as laser cones. Minor adjustments of the laser source with respect to the lenticular sheet may vary the size and shape of the laser cone that provides improved Light Detection and Ranging (LIDAR) systems. A diffraction grating added to the path of the laser beam causes a laser pattern of a matrix of lines to be produced which also provides improvement. Interference between multiple lenticular sheets may be used to deviate a laser beam to protect military assets from laser-guided projectiles and / or laser acquisition.SELECTED DRAWING: Figure 20

Description

[Technical field]

[0001] The present invention relates generally to the manipulation of light beams, and more particularly to systems and methods for laser scattering, deflection and manipulation. [Background technology]

[0002] Laser stands for "light amplification by stimulated emission of radiation." A laser differs from other light sources in that it emits light that is both spatially and temporally coherent. Spatial coherence allows the laser to be focused to a narrow spot, enabling applications such as laser cutting and lithography. Spatial coherence also allows the laser beam to remain narrow over long distances (collimation), enabling applications such as laser pointers. Lasers can also have high temporal coherence, allowing them to emit an ultra-narrow spectrum of light, i.e., they can emit monochromatic light. Temporal coherence can be used to generate pulses of light as short as 1 femtosecond.

[0003] Lenticular sheeting is a translucent plastic sheet with a series of vertically aligned plano-convex cylindrical lenses called lenticules on one side and flat surfaces on the other side, profiled and fabricated by precision extrusion. The lenticules help transform 2D images into various optical illusions, and when the orientation of the lenticular sheeting is changed, the viewer can see lenticular special effects. Lenticular sheets can be fabricated from acrylic, APET, PETG, polycarbonate, polypropylene, PVC or polystyrene. Each of these different materials has different levels of temperature and UV light sensitivity.

[0004] An important property of a lenticular sheet is the lenticular density. The lenticular density is expressed as lenses per inch or lenticules per inch (LPI). The thickness of the lenticular sheet is usually, but not always, inversely related to the LPI: the lower the LPI, the thicker the lenticular sheet. Another important property of a lenticular sheet is the viewing angle. The viewing angle of a lenticular sheet is the v-shaped area where the lenticular image can be clearly seen.

[0005] A diffraction grating is a plate of glass, plastic or metal with closely spaced parallel lines that produce a spectrum by diffraction and interference of light. A diffraction grating is an optical component with a periodic structure that splits and diffracts light into several beams traveling in different directions. The color that appears is a form of structural coloration. The direction of the beam depends on the spacing of the grating and the wavelength of the light, so that the grating acts as a dispersive element. Holographic diffraction gratings are very efficient embossed holographic optical elements (HOEs). Diffraction gratings are used for direct viewing and analysis of spectra from various gas-filled tubes and other light sources. The pattern size, measured in lines per inch or lines per mm (millimeters), is an important characteristic of diffraction gratings. Some diffraction gratings have 13,500 lines per inch. Single-axis diffraction gratings have multiple parallel lines. Biaxial diffraction gratings have a first multiple parallel lines and a second multiple parallel lines perpendicular to the first multiple parallel lines. Diffraction gratings are used in experiments related to the study of light and color.

[0006] LIDAR (Light Detection and Ranging) is a laser-based remote sensing technology. The theory behind LIDAR is to aim a laser beam at a surface and measure the time it takes for the laser to hit the object. An optical sensor, typically at or near the laser source, detects these hits. Knowing that the laser travels at the speed of light, the distance to the detected surface can then be determined by multiplying the detection time by the speed of light and then dividing by two. LIDAR systems thus utilize at least one laser source and at least one sensor. LIDAR systems can be ground-based, underwater-based, space-based, or mounted on planes, cars or UAVs (unmanned aerial vehicles). Summary of the Invention [Means for solving the problem]

[0007] In one aspect of the disclosure, a system for redirecting a laser beam is provided. The system includes a laser source emitting an incident laser beam including a plurality of light rays that project as dots, and a lenticular sheet having a lens side including a plurality of parallel longitudinal lenticular lenses and a smooth side opposite the lens side. The laser source is directed toward the lens side of the lenticular sheet such that the incident laser beam strikes at least one of the plurality of parallel longitudinal lenticular lenses. A first portion of the plurality of light rays of the incident laser beam is redirected by refraction to form a refracted beam of a first shape. A second portion of the plurality of light rays of the incident laser beam is reflected by a surface of at least one of the plurality of parallel longitudinal lenticular lenses to form a reflected beam of a second specific shape.

[0008] In one embodiment, the laser source is oriented such that a first incident laser beam strikes at least one of a plurality of parallel longitudinal lenticular lenses perpendicularly, a first portion of the incident laser beam that is redirected by refraction represents a majority of the plurality of rays of the incident laser beam, and the first particular shape of the refracted beam is in the form of a triangular surface beam that is projected as a straight line.

[0009] In one embodiment, the lenticular sheet is placed in an upright position such that the parallel longitudinal lenses are oriented horizontally, the triangular beam is oriented vertically, and the projection line is vertical.

[0010] In one embodiment, the lenticular sheet is placed in an upright position such that the multiple parallel longitudinal lenticular lenses are oriented vertically, the triangular beam is oriented horizontally, and the projection line is horizontal.

[0011] In one embodiment, the laser source is oriented such that the incident laser beam strikes at least one of the multiple parallel longitudinal lenticular lenses at an angle of incidence perpendicular to the at least one of the multiple parallel longitudinal lenticular lenses such that a first portion of the multiple rays of the first incident laser beam that are redirected by refraction represents a majority of the multiple rays of the first incident laser beam, the first incident laser beam is in the same plane as a horizontal plane passing through at least one of the multiple parallel longitudinal lenticular lenses, and the specific shape of the refracted beam is in the form of a curved surface projected as an arc.

[0012] In one embodiment, the laser source is oriented such that a first incident laser beam strikes at least one of the plurality of parallel longitudinal lenticular lenses at an angle of incidence from normal such that the first and second portions together form a cone projecting onto a circle.

[0013] In one embodiment, the lens side of the lenticular sheet is coated with a reflective material such that a second portion of the plurality of light rays reflected by at least one surface of the plurality of longitudinal lenticular lenses includes all of the plurality of light rays of the incident laser beam.

[0014] In one embodiment, an anti-reflective layer or coating is provided on at least one of the lens side and smooth side of the lenticular sheet to reduce a second portion of the multiple light rays of the incident laser beam that are reflected by a surface of at least one of the multiple longitudinal lenticular lenses.

[0015] In one embodiment, the system further comprises at least one diffraction grating positioned between the laser source and the lenticular sheet such that the incident laser beam passes through the diffraction grating before passing through the lenticular sheet.

[0016] In one embodiment, the system further comprises at least one diffraction grating positioned after the lenticular sheet such that the incident laser beam passes through the diffraction grating after passing through the lenticular sheet.

[0017] In one embodiment, the lenticular sheet is mounted in an upright position such that the parallel longitudinal lenses are oriented horizontally, and the at least one diffraction grating includes at least one linear diffraction grating oriented such that its lines are oriented vertically.

[0018] In one embodiment, the lenticular sheet is mounted in an upright position such that a plurality of parallel longitudinal lenses are oriented at an angle to the horizontal plane, and at least one diffraction grating includes at least one linear diffraction grating oriented such that its lines are oriented vertically.

[0019] In one embodiment, the lenticular sheet is mounted in an upright position such that the plurality of parallel longitudinal lenses are oriented horizontally, and the at least one diffraction grating includes at least one biaxial diffraction grating oriented such that a first plurality of lines thereof are oriented vertically and a second plurality of lines thereof are oriented horizontally.

[0020] In one embodiment, the lenticular sheet is mounted in an upright position such that a plurality of parallel longitudinal lenses are oriented at an angle to the horizontal plane, and the at least one diffraction grating includes at least one biaxial diffraction grating oriented such that a first plurality of lines thereof are oriented vertically and a second plurality of lines thereof are oriented horizontally.

[0021] In another aspect of the disclosure, a system for steering two laser beams to form a cone is provided. The system includes a first laser source generating a first incident beam composed of a plurality of light rays that project onto a dot, a second laser source generating a second incident beam composed of a plurality of light rays that project onto the dot, and a double-sided lenticular sheet having a first lens side including a plurality of parallel longitudinal lenticular lenses and a second lens side opposite the first lens side including a plurality of parallel longitudinal lenticular lenses. The first laser source is directed towards a first side of the lenticular sheet such that the first incident beam strikes one of the plurality of parallel longitudinal lenticular lenses at an angle of incidence such that a majority of the first incident beam light rays are reflected to form a first curved surface. A second laser source is directed toward a second side of the lenticular sheet such that the second incident beam strikes an opposite side of one of the plurality of parallel longitudinal lenticular lenses at the same angle of incidence as the first laser source such that a majority of the second incident beam rays are refracted to form a second curved surface, the first and second curved surfaces together forming a cone that is projected as a circle.

[0022] In one embodiment, the double-sided lenticular sheet includes first and second single-sided lenticular sheets each having a lens side and a smooth side, and the first and second single-sided lenticular sheets are positioned back-to-back on their respective smooth sides.

[0023] In one embodiment, the system further comprises a sheet of light opaque material disposed between the smooth sides of each of the first and second single-sided lenticular sheets.

[0024] In one embodiment, the sheet of light opaque material comprises a two-sided mirror.

[0025] In one embodiment, the first lens side and the second lens side are coated or made of a reflective material.

[0026] In one embodiment, the smooth sides of the first and second single-sided lenticular sheets are coated with a reflective material.

[0027] In yet another aspect of the present disclosure, a system for steering two laser beams to form a cone is provided. The system includes a first laser source generating a first incident beam composed of a plurality of light rays that project onto a dot, a second laser source generating a second incident beam composed of a plurality of light rays that project onto the dot, and a lenticular sheet having a first lens side including a plurality of parallel longitudinal lenticular lenses and a second lens side opposite the first lens side including a plurality of parallel longitudinal lenticular lenses. The first laser source is directed towards a first side of the lenticular sheet such that the first incident beam strikes one of the plurality of parallel longitudinal lenticular lenses at a first angle of incidence such that the first incident beam light rays are refracted and reflected to form a first cone. A second laser source is directed toward a second side of the lenticular sheet such that the second incident beam strikes an opposite side of one of the plurality of parallel longitudinal lenticular lenses at an angle of incidence greater than the first angle of incidence such that the second incident beam light rays are refracted and reflected to form a second cone larger than and coaxial with the first cone.

[0028] In one embodiment, the first and second beams are separated when they strike one of a plurality of parallel longitudinal lenticular lenses such that there is a distance between the apex of the first cone and the apex of the second cone.

[0029] In yet another aspect of the disclosure, a method is provided for detecting at least one object using a light detection and ranging (lidar) system, the method including projecting a first incident laser beam at a first angle onto a first lens side of a double-sided lenticular sheet to generate a first half-cone of reflected light beams, projecting a second incident laser beam at a second angle onto a second lens side of the double-sided lenticular sheet to generate a second half-cone of reflected light beams that together with the first half-cone of reflected light beams form a full cone of reflected light beams, and detecting, by at least one sensor of the lidar system, a signal reflected from the at least one object when the at least one object crosses any one of the full cones of reflected light beams.

[0030] In one embodiment, the method further includes varying the first angle and the second angle to vary the size of the first half-cone and the second half-cone, respectively.

[0031] In yet another aspect of the present disclosure, a system for redirecting a laser beam is provided. The system includes a laser source for projecting an incident laser beam, a first lenticular sheet having a lens side including a plurality of parallel longitudinal lenticular lenses and a smooth side opposite the first side, and a second lenticular sheet having a lens side including a plurality of parallel longitudinal lenticular lenses and a smooth side opposite the first side. The first and second lenticular sheets are positioned such that the smooth side of the first lenticular sheet faces the smooth side of the second lenticular sheet, and the first and second lenticular sheets form a double-sided lenticular sheet. The laser source projects the incident laser beam through the first and second lenticular sheets.

[0032] In one embodiment, the second lenticular sheet is positioned such that its multiple lenticular lenses are parallel to and offset from the multiple lenticular lenses of the first lenticular sheet so as to create an interference pattern between the two lenticular sheets to deflect the laser beam.

[0033] In one embodiment, the second lenticular sheet is positioned such that its multiple lenticular lenses are angled to the multiple lenticular lenses of the first lenticular sheet to create an interference pattern between the two lenticular sheets to deflect the laser beam.

[0034] In one embodiment, the system further comprises a double-sided lenticular sheet having a first lens side including a plurality of parallel longitudinal lenticular lenses and a second lens side opposite the first side including a plurality of parallel longitudinal lenticular lenses, the double-sided lenticular sheet being positioned in front of or behind the first and second lenticular sheets with respect to the laser source.

[0035] In one embodiment, the first and second lenticular sheets are integrally formed.

[0036] In one embodiment, the first and second lenticular sheets and the double-sided lenticular sheet are integrally formed.

[0037] A method of fabricating a system for deflecting a laser beam includes the steps of providing a first lenticular sheet having a lens side including a plurality of parallel longitudinal lenticular lenses and a smooth side opposite the first side, providing a second lenticular sheet having a lens side including a plurality of parallel longitudinal lenticular lenses and a smooth side opposite the first side, and attaching the smooth side of the first lenticular sheet to the smooth side of the second lenticular sheet.

[0038] In one embodiment, the method further includes, prior to the attaching step, positioning the second lenticular sheet so that its multiple lenticular lenses are parallel to and laterally offset from the multiple lenticular lenses of the first lenticular sheet.

[0039] In one embodiment, the method further includes, prior to the attaching step, positioning a second lenticular sheet such that its multiple lenticular lenses are angled to the multiple lenticular lenses of the first lenticular sheet.

[0040] In one embodiment, the method further includes providing a double-sided lenticular sheet having a first lens side including a plurality of parallel longitudinal lenticular lenses and a second lens side opposite the first side including a plurality of parallel longitudinal lenticular lenses, and attaching the double-sided lenticular sheet to the lens side of the first lenticular sheet or to the lens side of the second lenticular sheet such that the plurality of parallel longitudinal lenticular lenses of the double-sided lenticular sheet are parallel to either the plurality of parallel longitudinal lenticular lenses of the first lenticular sheet or the plurality of parallel longitudinal lenticular lenses of the second lenticular sheet.

[0041] Embodiments of the present invention will now be presented with reference to the accompanying drawings. [Brief description of the drawings]

[0042] [Figure 1] A side perspective view of a system for scattering a laser beam directed generally perpendicular to the lens side of an upright single-sided lenticular sheet having horizontally oriented longitudinal lenticular lenses on its lens side and an opposite smooth side. [Diagram 2] A top front perspective view of a system for scattering a laser beam directed approximately perpendicular to the lens side of an upright single-sided lenticular sheet having vertically oriented longitudinal lenticular lenses on its lens side and an opposite smooth side. [Diagram 3] A side perspective view of a system for scattering a laser beam directed at a small angle with respect to a normal to the lens side of an upright single-sided lenticular sheet having a horizontally oriented longitudinal lenticular lens on its lens side and an opposite smooth side, where the laser beam is in approximately the same horizontal plane as the longitudinal lenticular lens onto which it is projected. [Figure 4] A side perspective view of a system for scattering a laser beam directed at an angle greater than the angle in Figure 3 relative to a normal to the lens side of an upright lenticular sheet having horizontally oriented longitudinal lenticular lenses on its lens side and an opposite smooth side, where the laser beam is in approximately the same horizontal plane as the longitudinal lenticular lenses onto which it is projected. [Figure 5A] FIG. 5 is a side perspective view of a system for scattering a laser beam directed at a larger but similar angle to that of FIG. 4 relative to a normal to the lens side of a single-sided upright lenticular sheet having horizontally oriented longitudinal lenticular lenses on its lens side and an opposite smooth side, where the laser beam makes an angle with the horizontal plane passing through the longitudinal lenticular lenses onto which it is projected. [Figure 5B] A top view of a system for scattering a laser beam directed at an angle with respect to a normal to an upright lenticular sheet having horizontally oriented longitudinal lenticular lenses on its lens side and an opposite smooth side, the laser beam being directed toward the lens side of the lenticular sheet. [Figure 6] A top view of a system for scattering a laser beam directed at an angle with respect to a normal to an upright lenticular sheet having horizontally oriented longitudinal lenticular lenses on its lens side and an opposite smooth side, the laser beam being directed at the smooth side of the lenticular sheet. [Figure 7A]A side perspective view of a system for scattering two laser beams of different colors each directed to opposite sides of a double-sided lenticular sheet having longitudinal lenticular lenses oriented horizontally on each of its two opposite sides, where the two beams are directed to either side of a single location on each of the longitudinal lenticular lenses on the opposite sides, each of the two laser beams is angled with respect to a normal to each side of the lenticular sheet at the single location, and both beams are in the same horizontal plane through the longitudinal lenticular lenses at which they are directed. [Figure 7B] A top view of the system of FIG. 7A, but with the two color laser sources swapped and each oriented at a larger angle with respect to the normal to the respective surface of the double-sided lenticular sheet so that all incident light rays are reflected. [Figure 8A] FIG. 7C is a side perspective view of the system of FIG. 7B, where the two laser beams are the same color. [Figure 8B] 8B is a projection of the circle formed by the laser beam of FIG. 8A when projected onto a plane at a long distance. [Figure 8C] FIG. 1 is a schematic diagram illustrating an airborne lidar system utilizing a laser cone to detect enemy ground forces. [Figure 8D] FIG. 1 is a schematic diagram illustrating a lidar system utilizing a laser cone used by snipers to detect enemy ground forces. [Figure 8E] FIG. 1 is a schematic diagram illustrating a ground-based lidar system utilizing multiple laser cones to detect missiles. [Figure 8F] FIG. 1 is a schematic diagram illustrating the detection of an enemy aircraft by an airborne lidar system utilizing a laser cone mounted on another fighter aircraft. [Figure 8G] FIG. 1 is a schematic diagram depicting an enemy aircraft about to be detected by a ground-based lidar system utilizing a laser cone. [Figure 9A]A top view of a system for scattering two laser beams of different colors each directed to opposite sides of a double-sided lenticular sheet having longitudinal lenticular lenses oriented horizontally on each of its two opposite sides, where the two beams are directed to different locations on the longitudinal lenticular lenses on each of the opposite sides, where each of the two laser beams is at a different angle with respect to the normal to each side of the lenticular sheet, and where both beams are in the same horizontal plane through the longitudinal lenticular lenses at which they are directed. [Figure 9B] 9B is a projection of the circle formed by the laser beam of FIG. 9A when projected onto a plane at a long distance. [Figure 10A] A top view of a system for scattering a laser beam, the laser beam being directed at an angle with respect to a normal to an upright lenticular sheet having horizontally oriented longitudinal lenticular lenses on its lens side and an opposite smooth side, the laser beam being directed toward the lens side of the lenticular sheet at an angle such that all rays of the laser beam are reflected from the lenticular lenses on the lens side. [Figure 10B] A top view of a system for scattering two laser beams each directed at corresponding lens sides of two back-to-back single-sided lenticular sheets having horizontally oriented longitudinal lenticular lenses, where the two beams are directed to either side of a single location on each corresponding longitudinal lenticular lens on the opposite side, each of the two laser beams making the same angle with respect to the normal to each side of the lenticular sheet at the single location, and the two lenticular sheets being separated by a bright opaque sheet. [Figure 10C] A system similar to that of FIG. 10B is illustrated, but using two back-to-back lenticular sheets 250, each having a highly reflective lens side. [Figure 11] 1 is a flow chart for a method of detecting objects by a lidar system utilizing a double-sided lenticular sheet. [Figure 12] FIG. 2 is a top view of a linear diffraction grating. [Figure 13]FIG. 2 is a top view of a biaxial diffraction grating. [Figure 14] FIG. 1 is a perspective schematic diagram illustrating a spectrum being generated by directing light from a white light source through a linear diffraction grating. [Figure 15] FIG. 1 is a side perspective view illustrating the generation of multiple beams as a result of shining a laser beam through a linear diffraction grating. [Figure 16] FIG. 1 is a side perspective view illustrating the generation of multiple beams as a result of shining a laser beam through a dual-axis diffraction grating. [Figure 17] A side perspective view illustrating a system for generating multiple beam patterns by shining a laser beam through a linear lenticular sheet having a linear diffraction grating with vertical lines and lenticular lenses oriented horizontally. [Figure 18] FIG. 18 is a side perspective view illustrating a system similar to that of FIG. 17, but where the lenticular sheet is rotated approximately 45 degrees relative to the linear diffraction grating. [Figure 19] A side perspective view illustrating a system for generating multiple beam patterns by shining a laser beam through a linear lenticular sheet having a biaxial diffraction grating and horizontally oriented lenticular lenses. [Figure 20] FIG. 20 is a side perspective view illustrating a system similar to that of FIG. 19, but where the lenticular sheet is rotated approximately 45 degrees relative to the biaxial diffraction grating. [Figure 21] FIG. 1 is a side view illustrating a system of two back-to-back linear lenticular lenses with a horizontal offset between them used to redirect a laser beam. [Figure 22] FIG. 2 is a top view illustrating a system of two back-to-back linear lenticular lenses with an angular offset between the lenses. [Diagram 23] FIG. 1 is a side view illustrating a system of two back-to-back linear lenticular lenses, with the lenticular lenses aligned with each other, used to redirect a laser beam. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0043] Embodiments of the present invention will be presented here by way of example only and not by way of limitation. With the aid of a lenticular lens, the beam path of one or more laser elements can be significantly modified to change the laser beam from the point where the beam hits the lenticular lens into a flat surface, a shallow curve, a deep curve or a cone.

[0044] Referring to FIG. 1, a system 100 for manipulating a laser beam is depicted. The system 100 includes a laser source 110 that emits an incident laser beam 120 that forms dots when projected onto a surface. The incident laser beam 120 is directed perpendicularly to a linear lenticular sheet 150. The linear lenticular sheet 150 has a lens side 151 and an opposite smooth side. The lens side 151 of the linear lenticular sheet 150 includes a plurality of longitudinal lenticular lenses 155 that are oriented horizontally. The incident laser beam 120 is generally narrow and focused so that it projects onto a single longitudinal lenticular lens 155 or onto a small number of adjacent lenticular lenses 155 on the lens side 151 of the lenticular sheet 150. This depends on the density of the lenticular sheet 150, measured in lenses per inch or LPI. For a lenticular sheet with low lens density, all of the rays of the incident laser beam 120 may strike a single longitudinal lenticular lens 155. However, for a lenticular sheet with high lens density 150, the rays of the incident laser beam 120 strike multiple adjacent lenticular lenses 155. Each individual ray of the incident laser beam 120 is refracted at a different angle by one or more longitudinal lenticular lenses 155. The resulting rays 125 are redirected such that they are diffused and projected from the opposite smooth side of the lenticular sheet 150 in the form of multiple rays forming a triangular plane 128. In response to projecting onto the plane, the redirected rays 125 form a vertical line pattern 130. The lenticular sheet used in FIG. 1 has a relatively high lens density. Further observation of the lines 130 reveals that the lines 130 are composed of multiple closely spaced dots. A small number of rays 127 of the incident laser beam 120 are reflected from the surface of the lenticular lens 155 in the form of very narrow triangular planes. The rays 127 form a small line 132 when projected onto a plane on the same side as the laser source 110.

[0045] The orientation of the line pattern 130 formed by the diffusion of the incident laser beam 120 by the refraction of its rays through one or more longitudinal lenticular lenses 155 depends on the orientation of the one or more longitudinal lenticular lenses 155 onto which the incident laser beam 120 is projected. In FIG. 1, the lenticular sheet is oriented such that the lenticular lenses 155 are oriented horizontally, and the resulting line pattern 130 is vertical. FIG. 2 depicts a system 100, which is similar to the system 100 of FIG. 1, except that the lenticular sheet 150 is installed in an upright position and is oriented such that the multiple longitudinal lenticular lenses 155 are oriented vertically. When the laser source 110 projects the incident laser beam 120 onto one or more vertically oriented longitudinal lenticular lenses 155 of the lenticular sheet 150, the rays of the incident laser beam 120 are refracted by the lenticular lenses 155 to generate redirected rays 126 in the form of triangular planes 129. When projected onto a flat surface, the light rays 126 form a horizontal line pattern 135 behind the smooth side of the lenticular sheet 150. The lenticular sheet 150 used in Figure 2 has a low lens density, so the line pattern 135 is illustrated as a single line. However, like line pattern 130, line pattern 135 is composed of a number of closely spaced dots.

[0046] In both Fig. 1 and Fig. 2, the laser beam 120 is perpendicular to the lenticular sheet. Thus, the effect of the lenticular lens 155 on the laser beam 120 is symmetric. Fig. 3 depicts a system 100 for redirecting a laser beam 120 similar to that of Fig. 1, except that the laser beam 120 is directed to the lens side 151 of the lenticular sheet 150 at a horizontal incidence angle θ with respect to the perpendicular to the lens side 151 depicted by the line 184. The incidence angle θ is such that the overwhelming majority of the rays of the incident laser beam 120 are refracted by the one or more longitudinal lenticular lenses 155 in the form of redirected rays 135. Only a minority of the rays of the incident laser beam 120 are reflected by the one or more longitudinal lenticular lenses 155 in the form of reflected rays 137. The incident laser beam 120 is maintained in a horizontal plane through the lenticular lens 155 at which it is directed. The angled orientation of the laser beam 120 relative to the lenticular lens 155 causes the individual rays of the laser beam 120 passing through the lenticular lens 155 to be refracted in two different general directions. Due to the curved (convex) shape of the lenticular lens 155, the rays of the laser beam 120 tend to be turned (refracted) in a vertical direction as seen in FIG. 1. Additionally, the incidence angle θ at which the laser beam 120 is oriented with respect to a direction perpendicular to the lenticular lens 155 tends to cause the individual rays of the laser beam 120 to be additionally refracted in a horizontal direction. Because the rays of the incident laser beam 120 strike different regions of the lenticular lens 155, each having a substantially different thickness (due to the curvature of the lenticular lens surface), each of the rays of the laser beam 120 is therefore refracted by a different angle in the horizontal direction. As a result, the redirected light rays 135 emerging from the smooth side of the lenticular lens 155 end up taking the shape of a curved surface 138 (in the form of a partial cone) that projects an arc pattern 140 when it strikes a flat surface. A small portion of the rays of the incident laser beam 120 are reflected from the lens-side surface of the lenticular lens 155. The reflected light rays 137 form a curved surface on the same side of the lenticular sheet 150 as the laser source 110. When projected onto a flat surface, the reflected light rays 137 projected a small arc 142.

[0047] 4 depicts a system 100 similar to that of FIG. 3, except that the angle of incidence θ of the beam 120 onto the lenticular sheet 150, relative to the normal 184, is greater than that of FIG. 3. As the angle of incidence θ is increased, a majority of the rays of the incident laser beam 120 are reflected from the lens side of the lenticular lens 155 surface, illustrated as reflected rays 137. The reflected rays 137 form a curved surface that projects as an arc 162 that is in the shape of a partial ellipse. The curved surface formed by the reflected rays 137 and the corresponding projected arc 162 are on the same side of the lenticular sheet 150 as the laser source 110 in front of the sheet 150. Depending on the angle of incidence θ of the incident laser beam 120 relative to the normal 184, fewer rays pass through the lenticular lens 155, are curved and refracted as described above, and project an arc 160 behind the lenticular sheet 150. The resulting projected pattern is an ellipse 165 composed of complementary arcs 160 and 162. Ellipse 165 is a projection of the ellipsoidal cone formed by reflected rays 137 and refracted rays. It has been observed that when the lenticular sheet is perpendicular to the surface onto which the laser pattern is projected (e.g., a wall), ellipse 165 projects close to a perfect circle, and thus reflected rays 137 and refracted rays 135 together form a complete cone, as illustrated in FIG. 5A.

[0048] 5A illustrates a variation of the system 100 of FIG. 4. An incident laser beam 120 has an angle of incidence θ with respect to a normal 184 to the lenticular lenses 155 of the lenticular sheet 150. Additionally, the incident laser beam 120 is angled by an angle β with respect to a horizontal plane through the lenticular lenses 155, which is depicted as a plane through lines 184 and 185. The surface onto which the resulting refracted and reflected rays 135 and 137 are projected is perpendicular to the lenticular sheet 150. Thus, the refracted and reflected rays approximate a perfect circular cone 180 that projects as a circle made up of arcs 160 and 162. The angle β shifts the circle upward with respect to the lenticular sheet 150, as shown. The light rays 135 and 137 are shaped together as a cone 180 that projects a circle; however, the cone is partially projected in front of and partially projected behind the lenticular sheet 150 due to the fact that it is partially formed from reflected rays and partially formed from refracted rays. Thus, a laser cone can be formed by using the laser source 110 and the lenticular sheet 150. The cone can be steered up or down by changing the angle β with respect to the horizontal plane as mentioned.

[0049] 5B is a top perspective view illustrating laser beam 120 being directed at a wide angle toward the lens side of lenticular sheeting 150, where lenticular lens 155 is parallel to a horizontal plane passing through laser beam 120. The left arc 162 is created by beam 120 reflecting off lenticular lens 155 on the left (lens) side of sheeting 150 in the form of reflected ray 127 projecting as arc 162. Conversely, the right refracted arc 160 is created by beam 120 refracting through lenticular lens 155 and exiting the smooth side of lenticular sheeting 150 as ray 125 projecting as arc 160.

[0050] The above results reveal that a laser plane or cone can be generated as the beam is spread from the lenticular material into shapes such as lines 130 and 135, arcs 140 and 142, and arcs 160 and 162. Unlike some prior art methods where an incident laser beam may be utilized to generate shapes by turning a mirror, the system 100 presented herein has no moving parts. A variety of line, arc, and cone shapes can be generated by simply changing the angle of the laser beam with respect to the lenticular sheet.

[0051] It should be noted that while the previous figures illustrated the laser beam being directed at the lens side of the lenticular sheeting, the present system was also operated while projecting the laser beam at the smooth side of the lenticular sheeting instead. For example, referring to FIG. 6, beam 120 is directed at the smooth side 152 of a single-sided lenticular sheeting 150. In this case, the left arc 160 formed is due to the beam refracting through the sheeting and exiting the lenticular lens 155 on the lens side of the sheeting as ray 135 forming arc 160. Conversely, the right arc 162 of the figure is formed by the laser beam 120 reflecting off the smooth side of the lenticular sheeting 150 as ray 137 forming arc 162. Additionally, a bright dot 167 is also formed in the center of arc 162 due to beam 120 undergoing specular reflection from the smooth side of the lenticular sheeting 150. It has been observed that the refracted arc 160 is brighter than the reflected arc 162. The exception is the bright dot 167 on the reflected arc. This reveals that it is preferable to use the lens side 151 of the lenticular sheet to generate the laser cone. It has also been observed that as the beam 120 is angled with respect to the lenticular sheet 150 by a small amount, the bright dot 167 can move along the arc 162. Furthermore, as the angle of the beam 120 with respect to the smooth surface of the lenticular sheet 150 approaches being perpendicular to that surface, the intensity of the bright dot 167 increases. The observation made regarding the bright dot 167 being movable along the arc 162 points out that small changes to the angle of the incident laser beam 120 with respect to the lenticular lens 155 rotate the rays 137 and 135. In essence, changing the angle of incidence resizes the cone, with all the dots on the arcs 160 and 162 rotating in a circumferential direction as they expand and contract as the cone is resized. For example, decreasing the angle of incidence θ by a small amount causes the rays 137 and 135 to generate a slightly larger cone 180. As the individual dots that make up arcs 160 and 162 move towards their new positions, they are also moving circumferentially.The opposite happens when the incidence angle θ is increased, the cone 180 shrinks, and the individual dots forming the arcs 160 and 162 rotate in opposite directions as they move to their new positions. This has been confirmed to be true when the incident laser beam is directed toward the lens side 151 of the lenticular lens. The rotation of the dots (and thus the beam projecting the dots) is initially observed with respect to the smooth side 152 due to the presence of the bright dot 167, but it applies to all of the dots forming the arcs 160 and 162. Thus, fine adjustment of the incidence angle θ can be used to move the dots circumferentially. This has significant advantages with regard to describing applications of the generated laser cones.

[0052] There are benefits to spreading the laser beam and / or projecting various line, arc and elliptical shapes with the laser light in the form of a laser surface, curved surface or cone. For example, security systems using a thin, focused laser beam are likely to be triggered by any small object that breaks the beam. Thus, many false positive triggers may occur due to insects, small birds or rodents passing through the beam. However, if the beam is spread to a surface (projected as a line), curved surface (projected as an arc) or cone (projected as a circle), it may take a larger object, such as a human, drone or vehicle, to break a larger portion of the beam and trigger an alert condition. The size of the surface and cone can also be changed as conditions may change or change for different areas. Advantageously, changing the dimensions of the laser surface or cone is a simple matter of changing the angle and / or position of the projection of the incident laser beam onto the lenticular lens. Additionally or alternatively, different lenticular sheets may be used, each with a different viewing angle or lens density (LPI). For example, for the same laser beam or beams projected at the same angle, lenticular sheets of different viewing angles may produce projected laser cones or surfaces of different dimensions.

[0053] With reference to Figures 7A and 7B, a system 200 for projecting a laser cone 180 is provided. The system 200 is composed of two laser sources 210a and 210b and a double-sided lenticular sheet 170. The double-sided lenticular sheet 170 has a number of longitudinal lenticular lenses 175 on both sides thereof. The laser source 210a projects an incident laser beam 220a having a first color, and the laser source 210b projects an incident laser beam 220b having a second color different from the first color. For example, the laser beam 220a may be green, while the laser beam 220b may be red. Both the incident laser beams 220a and 220b are directed to opposite sides of the double-sided lenticular sheet 170 and at different angles of incidence. The incident laser beam 220a is reflected from one side of the lenticular lens 175a of the lenticular sheet in the form of light rays 137. When the light beams 137 hit or contact the plane, they project an arc 180a in front of the lenticular sheet 170. The incident laser beam 220b, on the other hand, is projected on the opposite side of the lenticular lens 175a at a smaller angle of incidence with respect to the normal to the lenticular sheet 170. Therefore, the beam 220b projects on the rear side of the lenticular sheet 170 and is reflected from the lenticular lens 175a. The light beam reflected from the lens 175a as the light beam 135 forms a curved surface, such as a partial cone, and projects an arc 180b in front of the lenticular sheet. Advantageously, the two arcs 180a and 180b are complementary, as long as the two beams are projected on opposite sides of the same location of a particular lenticular lens of the double-sided lenticular sheet 170. The resulting light beam configuration consisting of the light beams 135 and 137 is in the shape of a cone 180. The angle of incidence of incident laser beam 220a is selected so that a majority of the light is reflected as light ray 137, while the angle of incident laser beam 220b is selected so that a majority of the light is reflected more densely as light ray 135. If the angle of incidence of laser source 210a is large enough, laser beam 220a will pass through lenticular sheet 170 and refract in an arc onto the other side near arc 180b or onto arc 180b.

[0054] 7B, the angles of incidence of the incident laser beams 220a and 220b are both large such that both beams are reflected from respective surfaces of the double-sided lenticular lens 170. The resulting laser cone 180 is thus very thin, but consists entirely of reflected rays.

[0055] 8A illustrates a system 300 in which two laser sources 310a and 310b project laser beams 320a and 320b of the same color. Thus, the resulting cone 180 appears to originate from the same laser source even though it is a composite of reflected light ray 137 from incident laser beam 320a and refracted light ray 135 from incident laser beam 320b. The result is a laser cone 180 composed of two half laser cones 180a and 180b that are monochromatic. The laser cone 180 has several useful applications, as shown below.

[0056] Figure 8B illustrates that the laser cone 180, for example, generated by the system 300 of Figure 8A, is actually composed of multiple light rays that project as a circumferential dot 182 when projected onto a surface far away from the laser source. A typical arc and cone is composed of hundreds of dots. However, as described with respect to Figure 6, small adjustments to the angle of incidence of the incoming laser beam rotate the dots 182 circumferentially (either clockwise or counterclockwise). Thus, as will be described below, this can be used to detect objects that may normally pass undetected between the light rays projecting those dots.

[0057] Lidar (Light Detection and Ranging) currently utilizes one or more pulsed lasers that reflect a signal from the surrounding environment, and a sensor to detect the reflected signal. Thus, by measuring the time it takes for the signal to reflect back to the sensor, a computer can determine the distance to an object and / or create a three-dimensional map of the surrounding area and surface characteristics. Terrain lidars use near-infrared lasers to map land, and bathymetric lidars use green lasers to penetrate water and map ocean and riverbeds. The use of lidar underwater, however, is often limited to only a few tens of feet. Lidar is a key element of autonomous vehicles, and the more accurate the lidar, the safer the system can be. Lidar has also been tested on aircraft to determine areas of turbulence ahead of the aircraft, allowing the aircraft to avoid or prepare for those areas. Lidar can also be used by civilian organizations or the military to search for targets in shallow water, on land, or in the air (clear weather) or in space. Low-observable aircraft, drones, birds and bats are difficult to detect by radar, but can be detected by this type of system.

[0058] Using the above system, instead of a laser point, planes, curves and / or cones can be created to allow the sensor to determine more detail in a shorter time period and achieve larger angles than current lidar systems. In one embodiment, the laser cone can be made variable from narrow to wide to scan large portions of the sky, while the sensor can receive any reflections from other aircraft, contrails, aircraft turbulence, natural turbulence, drones, missiles, projectiles, rockets, bullets, balloons, birds, bats or swarms of insects.

[0059] FIG. 8C illustrates a laser cone 180 composed of multiple light beams 137 generated by an airborne lidar system used to detect ground forces. FIG. 8D illustrates a laser cone used by a lidar system used by a sniper to detect one or more enemy forces. FIG. 8E illustrates a land-based lidar system utilizing three laser cones 180, each composed of multiple light beams 137. The land-based lidar is used to detect missiles. FIG. 8F illustrates a laser cone generated by an airborne lidar system used to detect enemy aircraft. FIG. 8G illustrates a ground-based lidar system projecting a cone 180 for detecting aircraft. The cones illustrated in FIGS. 8C-8G are composed of multiple light beams as described above and project as a circle as illustrated in FIG. 8B. Typical arcs and cones are composed of hundreds of dots. To ensure that an object to be detected does not pass between two circumferentially adjacent light beams, the light beams are moved circumferentially such that each light beam casts an arc between its current location and the location of the adjacent light beam. In one embodiment, this is accomplished by slight adjustment of the laser source to change the angle of incidence of the incident laser beam(s) with respect to the lenticular lens, hi another embodiment, the lenticular sheet is moved or rotated slightly to change the angle of incidence of the incident laser beam(s) such that the refracted light rays are rotated slightly circumferentially as described.

[0060] FIG. 9A illustrates a system 200 consisting of a double-sided lenticular sheet 170 and two laser sources 210a and 210b. Laser source 210a projects an incident laser beam 220a, and laser source 210b projects an incident laser beam 220b. Laser beam 220a generates a reflected arc 270a and a refracted arc 270b as described above. Similarly, laser beam 220b generates a reflected arc 280a and a refracted arc 280b. Laser beam 220b is angled from the normal 184 to the lenticular sheet 170 by a larger angle than that of laser beam 220a. Thus, the arcs 280a and 280b generated by incident laser beam 220b are larger in dimension than the arcs 270a and 270b generated by incident laser beam 220a. As a result, the laser cone 280 formed by the reflected and refracted rays from beam 220b is larger than the laser cone 270 formed by the reflected and refracted rays from beam 220a. The two cones are coaxial because beams 220a and 220b are projected on each side of the same lenticular lens. In the depicted embodiment, the laser beams are directed to different lateral points of the lenticular lens, which are horizontally separated by a distance (d). The resulting cones are thus nested such that an object traveling inside cone 280 can be detected by cone 270. The laser source 210a can be moved in the horizontal plane to change the distance (d). Thus, the size and position of cone 270 with respect to cone 280 changes. The resulting effect is that the entire volume between cones 270 and 280 can be swept and covered by a laser beam that can be used to detect any object between the cones.

[0061] In one embodiment, the laser source 210a may be moved back and forth, for example, to sweep the volume between the cones 270 and 280; additionally, the laser source 210a may have its angle of incidence slightly altered to rotate the light rays forming the cone 270. For example, with reference to FIG. 9B, dot 271 represents the light rays of the cone 270 as projected onto a plane. Similarly, dot 281 represents the light rays of the cone 280 as projected onto a plane. If the laser source 210a is moved such that the distance (d) in FIG. 9A is smaller than the cone 270 expands, the dot 271 approaches the dot 281. Furthermore, if the laser source 210a is angled slightly to rotate each dot 271 to the location previously occupied by the adjacent dot, the volume between the cones 270 and 280 is completely covered for object detection both radially and circumferentially. In another embodiment, the laser source 210b is moved so that the cone 280 is smaller, and the laser source 210a is moved so that the cone 270 is smaller until it is almost eliminated. This is done by angling the laser source 210a until it is at a large obtuse angle (close to 180 degrees) from the normal to the lenticular sheet 170. Thus, the entire volume encompassed by the laser cone 280 is swept for object detection. For example, the cone 270 may be half the size of the cone 280, and it may take the same time for the cone 280 to be reduced in size until it matches the initial size of the cone 270 as it takes for the size of the cone 270 to be almost eliminated. During that time, the entire volume of the cone 280 is swept radially. Alternatively, fewer laser sources may be added and their respective beams may also be directed to be displaced from each other by distances such as (d). Thus, several concentric cones may be utilized to cover the volume encompassed by the outermost laser cone 280. In such an embodiment, it may not be necessary to vary the size of the laser cones; simply rotating them so that each cone area is circumferentially cleaned may be sufficient.

[0062] A fixed laser cone can also be rotated as radar or lidar do, rather than varying the cone angle. Lidar often uses mirrors to rapidly rotate the laser source, but the same can happen with these lines, arcs or cones. A combination of rotating cones and variable angles of the cone from narrow to wide can also be used, and two or more lasers can be used for multiple cones of similar or different angles, and with the same lens or other lenses, to increase the scanned range. The laser cone can be fixed, with two or more lasers used for multiple cones of variable angles. In space, this system can be used to detect other space-based objects, whether natural (meteorites, asteroids, comets...) or man-made (satellites, spacecraft, astronauts, space junk...).

[0063] 10A, a system 100 similar to that illustrated in FIGS. 1-6 can be used to generate a partial laser cone that projects as an arc 140. Laser source 110 projects an incident laser beam 120 that is angled at a large angle θ with respect to a line 184 normal to the surface of the lens side 151 of a single sided lenticular sheeting, such as sheeting 150. This produces only reflections of rays of incident laser beam 120 in the form of reflected rays 127 that project as arc 140. As discussed above, by further increasing angle θ, the arc eventually disappears completely.

[0064] It has been observed that in order to generate a circular cone generated solely by reflection of the laser beam from the double-sided lenticular sheet 170, the angle of incidence of the incident laser beam 120 needs to be large with respect to the normal to the lenticular sheet. If the angle is not large enough, some of the light rays will be refracted and others will be reflected. The resulting pattern may be two cones instead of one. In the system illustrated in FIG. 10B, the double-sided lenticular sheet 170 is replaced by two back-to-back single-sided lenticular lens sheets 150 and a sheet 160 of light opaque material or mirror inserted between them. In this configuration, the light opaque material or mirror prevents refraction of the laser beam through the lenticular lens sheet and instead reflects the beam. Thus, the resulting pattern may be a larger cone, as the angle may be larger than that used in FIG. 10A, for example.

[0065] FIG. 10C illustrates a system similar to that of FIG. 10B, but using two back-to-back lenticular sheets 250, each with a highly reflective lens side. For example, the lenticular lenses of the lenticular sheet 250 may be made from a highly reflective material or have a highly reflective coating. The high reflectivity of the lens side prevents refraction of the laser beam through the lenticular lens sheet, instead reflecting the beam. Thus, the resulting pattern may be a larger cone, as the angle may be larger than that used in FIG. 10A, for example.

[0066] The laser source may be moved slightly left or right relative to the lenticular sheet to move the dots clockwise or counterclockwise. If each projected dot is close to its neighbors, only a small movement by the laser source may be required to make each dot cross the interval to the next adjacent dot position. Another possible embodiment is to move the lenticular sheet itself. Only a small movement by the sheet is required to move the dots across the interval. In one embodiment, the lenticular sheet may be in the form of a cylinder and may be slightly movable. A simple gear and spring mechanism may be utilized to create a slow and steady movement. For example, a winding mechanism similar to an old wind-up watch may be used. The mechanism may include a gear reduction to provide a slow but steady turning motion that rotates one of the laser source and the lenticular material used to redirect the laser beam of the laser source. If the same mechanism is applied to a first laser source to move it slightly left or right, the second laser source may be required to offset the stopping of the dot when the first laser source reaches the left or right extreme points while the second laser is in the middle of a sweep. Rotating mirrors may also be utilized to rotate lines, arcs or cones.

[0067] Experiments have revealed that stealth aircraft, regardless of shape, cannot effectively scatter the electromagnetic energy present at the small wavelengths of light emitted by the lidar. A fast moving jet plane or a new hypersonic missile may be able to fly through the intervals between the described deflected laser beams, but is less likely to do so if the beams forming the described cone are also moving in a clockwise or counterclockwise direction, accomplished by moving either a lenticular lens or a laser source. Additionally, the turbulence generated by such vehicles can also be detected by the lidar.

[0068] 11 depicts a method 1100 for detecting an object using a lidar system. At step 1110, a first incident laser beam is projected onto a first lens side of the double-sided lenticular sheet to generate a first half-cone of reflected light. At step 1120, a second incident laser beam is projected at a second angle onto a second lens side of the double-sided lenticular sheet to generate a second half-cone of reflected light that together with the first half-cone of reflected light forms a full cone of reflected light. At step 1130, a sensor of the lidar system detects a signal reflected from an object when the object crosses any one of the full cone of reflected light rays.

[0069] Figure 12 is a top view of the diffracting side of a linear (single axis) diffraction grating 1000 with multiple lines 1010. The opposite side of the diffraction grating 1000 is a smooth flat surface. Figure 13 is a top view of the diffracting side of a biaxial diffraction grating 1500 with multiple horizontal lines 1010 and multiple vertical lines 1020. The opposite side of the biaxial diffraction grating 1500 is a smooth flat surface.

[0070] 14 illustrates an incident light beam 20 directed toward the smooth surface of diffraction grating 1000 at an angle to the normal. The heterochromatic light rays comprising beam 20 are refracted in the same manner as they are refracted from the prism and separated into heterochromatic light rays 21, 22, 23, and 24.

[0071] 15 is a side perspective view illustrating an incident laser beam 120 being directed through a single axis diffraction grating 1000. The single axis diffraction grating 1000 causes the beam 120 to produce multiple diffracted laser beams 1024 that, when projected onto a flat surface such as a wall, produce multiple dots 1025 arranged in a line along the surface. Using a particular type of laser source, it has been observed that a diffraction grating of 1000 lines per millimeter (l / mm) produced three dots.

[0072] 16 is a side perspective view illustrating an incident laser beam 120 being directed through a dual axis diffraction grating 1500. The dual axis diffraction grating 1500 causes the beam 120 to produce a number of diffracted laser beams 1024 that, when projected onto a flat surface such as a wall, produce a number of dots 1025 arranged in a matrix on the surface.

[0073] Returning to FIG. 1, when an incident laser light beam 120 was directed nearly perpendicular to a linear lenticular sheet 150 with lenticular elements 155 oriented horizontally, the resulting pattern was a beam that formed as triangles and projected as vertical lines 130 on a flat surface. Each vertical line 130 is actually composed of hundreds of closely spaced dots. If multiple laser beams 1024 from FIG. 15 were passed through a lenticular sheet 150 such as that of FIG. 1, each of the diffracted laser beams 1024 of FIG. 15 would generate a line such as the line 130 of FIG. 1. Referring to FIG. 17, a laser source 110 directs an incident laser beam 120 through a linear lenticular sheet 150 with a lenticular lens oriented horizontally, followed by a linear diffraction grating 1000 oriented such that the diffracted lines are vertical, and abutting the diffraction grating 1000. The resulting pattern is a plurality of triangular vertical surfaces that project as vertical lines 1080. A close inspection of the vertical lines reveals that each line is made up of hundreds of closely spaced points. The number of vertical lines depends on the pattern density of the diffraction grating. Thus, the number of projected vertical lines can be increased.

[0074] 18, if the lenticular lens sheet 150 is rotated so that it is angled with respect to the diffraction grating 1000, the dots projected by the diffraction grating are no longer vertically aligned, and each of them produces a line when passed through the linear lenticular sheet. The resulting pattern is an equal number of closely spaced diagonal triangular laser faces that project as diagonal lines 1090, and each of the diagonal lines 1090 is made up of hundreds of dots.

[0075] The diffraction grating used in FIG. 19 is a biaxial diffraction grating 1500, according to an embodiment of the present disclosure. As previously described with respect to FIG. 16, when the incident laser beam 120 is projected through the biaxial diffraction grating 1500, a matrix of laser beams is formed that projects as a matrix of laser dots. For example, if the biaxial diffraction grating has a pattern density of 13,500 lines per inch, it has been found that a matrix pattern of 13×13 dots is projected by the diffracted laser beam. If a lenticular sheet 150 with multiple lenses is placed in the path of the diffracted laser beam 1024, each beam will generate a line as previously illustrated. If the lenticular sheet is placed such that the lenticular lenses are oriented horizontally, many of the lines 1080 will be aligned, and some substantially bright lines will be visible.

[0076] In Figure 20, the lenticular sheet 150 is rotated at an angle relative to the biaxial diffraction grating 1500. Thus, the matrix of dots produced by the diffraction grating is now oriented diagonally on the lenticular sheet 150. The resulting pattern is a plurality of lines 1090, which are diagonal. The lines 1090 are more numerous and more densely spaced than the lines 1080. Each of the lines 1090 is made up of hundreds of dots.

[0077] It has been observed that adding more grating sheets of different pattern densities in the path of the incident laser beam creates more diffracted beams that form dots. Passing the diffracted beams through the lenticular sheet converts each dot into a line, as mentioned, with each line being composed of hundreds or thousands of dots. Objects that enter the path of multiple beams are in the path of thousands of laser beams and can be detected with good resolution using the lidar system. Additionally, lidar systems utilizing thousands of laser beams in the form of a matrix are also sensitive to small objects. Thousands of laser beams can be closely spaced even at long distances, avoiding the need to perform sweeps similar to those performed with a laser cone. The limiting factor for the number of gratings used is the amount of laser light that is to be passed through and its intensity. A strong laser can still project enough power to be usable with multiple gratings, while a weak laser can only be used in conjunction with a few gratings. The application of the lidar system can dictate the strength of the laser used and, accordingly, the number of gratings, their pattern density, and their angles with respect to each other and with respect to the lenticular lens. Additionally, the distance to the object to be detected may dictate the number of grids to use. For example, for objects that are not far enough away, a few grids may be used since the resulting lines and dots are still closely spaced at close range. However, to detect objects that are far away, more grids would be desirable, producing more beams that are closely spaced, using a lenticular sheet. A stronger laser would then be needed, since more grids would reduce the amount of laser light passing through, which would affect the ability to detect the object using the lidar.

[0078] FIG. 21 illustrates a system for redirecting a laser beam by using two back-to-back linear lenticular sheets 150 and 450 with offset interference patterns therebetween. As shown, the individual lenticular lenses of sheet 150 are laterally offset from those of sheet 450 in the horizontal direction. An incident laser beam 120 directed at lenticular sheet 450 is redirected as a redirected ray 125 as it exits lenticular sheet 150. The interference pattern therefore deflects the laser beam. This is beneficial since laser designators are often used to mark targets in modern warfare. This is done for laser-guided bombs, missiles and precision artillery munitions. By deflecting the laser designator, there is a chance that the weapon will miss a weak spot in a target such as a tank, which often requires a direct hit of a specific location to disable.

[0079] Lasers are also increasingly being used by ground forces to target their weapons at the enemy. These lasers can operate at frequencies outside the visible spectrum and can be seen through night vision scopes or goggles. The material used in FIG. 21 works to deflect lasers not only in the visible spectrum, but also in the UV (ultraviolet), NIR (near infrared) and SWIR (shortwave infrared) and potentially those outside this range.

[0080] The result of deviating from the pinpoint accuracy of the laser may be that the soldier aims at the wrong place, consistently missing the target and not understanding why he is unable to hit. The disruptive element of the interference, concealing the target situation, may cause the enemy to assume that he has hit the target without even realizing that he has completely missed it. This may force the enemy to change his offensive or defensive posture or position, placing the concealed target behind our material, making it easier to find and identify the combatant, and targeting that adversary when he is most vulnerable. With the system of FIG. 21, moving the laser beam to the right will deflect it to the left and vice versa. This is indicated by the arrows, illustrating that the deflected laser beam 125 moves in the opposite direction to the incident laser beam 120. An observer aiming at the target may notice that the projected laser dot on the target is moving in the opposite direction to the direction the laser source is being moved. The observer may therefore suspect that there is some form of camouflage material in front of the target and conclude that the target will not be accurately hit if munitions are fired at the target using the observed dot.

[0081] 22 depicts an alternative arrangement of two back-to-back linear lenticular sheets 150 and 450. In this arrangement, the individual lenticular lenses of sheet 150 are angled horizontally to those of sheet 450, creating an interference pattern that displaces an incident laser beam passing therethrough.

[0082] FIG. 23 illustrates a system for redirecting a laser beam by using two back-to-back linear lenticular sheets 150 and 450, and an additional double-sided lenticular sheet 170, with offset interference patterns between them. As illustrated, the individual lenticular lenses of sheet 150 are offset horizontally from those of sheet 450. The double-sided lenticular sheet 170 is illustrated positioned between the laser source and lenticular sheets 450 and 150, however, lenticular sheet 170 may be positioned behind lenticules 150 and 450. An incident laser beam 120 directed at lenticular sheet 450 exits lenticular sheet 150 as a redirected beam as in FIG. 21, however, the redirected beam now passes through double-sided lenticular sheet 170. In this case, the beam is redirected when the laser source is moved in a particular direction, and the redirected beam 125 moves in the same direction. Advantageously, the redirected beam does not project onto a set target, but at the same time, the observer may not suspect that the beam is being redirected, since when the laser source is moved, the projected laser dot appears to move in the same direction, and thus the observer may be under the impression that the target has been hit when ammunition is fired in the direction of the observed projected dot.

[0083] Although the lenticular lenses are depicted to be substantially the same dimensions, it will be apparent to one skilled in the art that different lenticular sheets of different angles or lenses per inch (LPI) may be used interchangeably without affecting the way in which the present invention functions.

[0084] Although the lenticular sheet used in the illustrative embodiment consisted of a longitudinal lenticular sheet, other equivalent refractive and reflective materials could be used, for example, prism lenses, dove prism lenses, and dove prism lenses split in the middle could be used.

[0085] For all systems described herein that use lenticular lenses and / or diffraction gratings, the surfaces may be coated or manufactured with protective elements that may address some or all of the following, including but not limited to fog, water, fire, mud, dust, scratches, heat, cold and ultraviolet radiation.

[0086] Having thus described embodiments of the invention by way of example only, it should be understood that the invention defined by the appended claims is not limited to the specific details set forth in the above description of the illustrative embodiments, and that numerous variations and substitutions are possible without departing from the scope of the claims. [Explanation of symbols]

[0087] 20 Incident light beam 21 rays of light 22 Rays of Light 23 Rays of Light 24 Rays 100 Systems 110 Laser Source 120 Incident laser beam, incident laser light beam 125 Turned light beams, deflected laser beams, turning beams 126 Turning Ray 127 Reflected Light 128 Triangular plane 129 Triangular plane 130 Vertical Line Pattern, Line 132 Small Line 135 Horizontal line patterns, turning rays, refracted rays, lines 137 Reflected Light 138 Curved surface 140 Arc Pattern, Arc 142 Small arc 150 Linear Lenticular Sheet 151 Lens side 152 Smooth side 155 Lenticular lenses, lenticular elements 160 Arcs, inflected arcs, sheets 162 arc, reflective arc 165 oval 167 dots 170 Double-sided lenticular sheet 175 Lenticular Lens 180 Cone, Laser Cone 180a arc, half laser cone 180b arc, half laser cone 182 Circumference Dot 184 Lines, Perpendicular Lines, Vertical Direction 185 line 200 Systems 210a Laser source 210b Laser source 220a Incident laser beam 220b Incident laser beam 250 Lenticular Sheet 270 Laser Cone 270a reflection arc 270b refracted arc 271 dots 280 Laser Cone 280a reflection arc 280b Refraction Arc 281 dots 450 Linear Lenticular Sheet 1000 Linear (single axis) diffraction grating 1010 line, horizontal line 1020 Vertical Line 1024 Diffraction laser beam 1025 dots 1080 Vertical Lines 1090 diagonal line 1500 Biaxial Diffraction Grating β angle θ Horizontal angle of incidence, large angle

Claims

[Claim 1] 1. A system for redirecting a laser beam, the system comprising: a laser source emitting said laser beam; a lenticular sheet having a lens side including a plurality of parallel longitudinal lenticular lenses and a smooth side opposite the lens side; at least one diffraction grating having at least one biaxial diffraction grating oriented such that the first plurality of lines are oriented at a non-zero orientation angle with respect to the second plurality of lines; Equipped with The at least one diffraction grating and the plurality of parallel longitudinal lenticular lenses include: (a) at least one diffraction grating is between the laser source and the lenticular sheet, whereby the laser beam first passes through the at least one diffraction grating; or (b) the lenticular sheet is positioned between the laser source and the at least one diffraction grating such that the laser beam first passes through the lenticular sheet; the laser source is directed towards the lens side of the lenticular sheet such that an incident laser beam is incident on the plurality of parallel longitudinal lenticular lenses from the lens side; a first portion of the incident laser beam is redirected by refraction by at least one of the plurality of parallel longitudinal lenticular lenses to form a refracted beam of a first shape; A system in which a second portion of the incident laser beam is reflected by at least one surface of the plurality of parallel longitudinal lenticular lenses to form a reflected beam of a second particular shape.

Images