Patent Description:
The present invention relates to a riot shield, and in particular to the use of materials that interact with light to create improved displays suitable for use in simulated or immersive environments.

Display systems used in conjunction with simulators, virtual reality systems and augmented reality technologies which allow users to interact with, at least partially, simulated environments are known. Such conventional systems typically rely on computer monitors or stereoscopic displays and are primarily visual in nature, although the systems are sometimes augmented with audio or haptic feedback. Popular examples include flight simulator video games in which the players pilot virtual aircraft in a computer-simulated digital environment.

Augmented reality (AR) often refers to the combination of real world objects and computer generated digital data. Conventionally, AR uses of video and images that are digitally processed and augmented with the addition of computer-generated graphics.

Systems involving the use cameras that capture and track a user's position and movement are also known. For example, <CIT> describes a system that includes a depth camera that captures user position and movement, a three-dimensional (3D) display device that presents the user a virtual environment in 3D and a haptic feedback device that interfaces to the user via the sense of touch by applying, for instance, on or more of forces, vibrations and motions to the user to provide haptic feedback as he or she interacts with a virtual object in the virtual environment.

As the user moves through his physical space, his or her image is captured by the depth camera. Data from that depth camera is parsed to correlate the user's position with a position in the virtual environment. Where the user position or movement causes the user's representation in the virtual environment to touch a virtual object, a corresponding haptic feedback is provided to the user. Haptic feedback is provided through use of a glove coupled to the user's arm, the glove containing a plurality of electrodes that may provide a mild electrical stimulation to the user. When the user makes a movement in his or her physical environment that corresponds to grasping a virtual cylinder, the system may determine that this has occurred, and provide haptic feedback to the palm and fingers of the user that provides a similar haptic experience for the user as if he or she had grasped a physical cylinder within the physical space.

Other forms of interactive or virtual systems include displays that facilitate concealment, camouflaging and other simulated visual effects. This has helped inspire research into light and light-bending materials and related studies of effective arrangements optical instruments in order to achieve the desired effect. Much theoretical progress has been made in attempts to model culminating in a theoretical framework for a field of research sometimes called transformation optics.

Although many systems exist that simulate interesting and useful visual environments, such systems have often proven costly, requiring sophisticated and powerful processing capabilities, cameras used for tracking positions and movements, and algorithms to adapt generated or displayed video data with expected visual imagery. Improvements are thus desired. It is an object of the present invention to provide improved systems for simulation, interactive display or immersive environments using cost effective approaches. <CIT> discusses a full parallax three-dimensional display device. It comprises a projector array and an orthogonal cylinder raster screen. The orthogonal cylinder raster screen comprises the first cylinder raster and the second cylinder raster. The projector array and the orthogonal cylinder raster screen are put in order. The projector array projects images on the orthogonal cylinder raster screen. The raster directions of the first cylinder raster and the second cylinder raster of the orthogonal cylinder raster screen are parallel to the x-axis and the y-axis, respectively. <CIT> discusses a projection screen having lenticular lenses in which the directions of refraction differ by <NUM> degrees. Each lens is made in such a manner that the angles of refraction are varied from the central portion of the lens to its end portions so that an incident ray is uniformly dispersed throughout the service area. The surfaces of the lenticular lenses are finished to prevent a virtual image. <CIT> discusses a rear projection screen for use in a rear projection display apparatus. <CIT> discusses a multi-screen projector. <CIT> discusses a system for projecting changeable electronic content, such as video or digital still images, onto multiple surfaces. <CIT> discusses digital cloaking systems and methods.

Aspects of the present invention involve displays and simulated systems that use materials made from various arrangements of lenses and other optical materials to achieve visual effects with applicability in display systems, virtual reality, immersive environments, as well as in architecture, art, entertainment, displays, interactive systems and the like. These materials utilize the refraction and reflection of light and other rays in the electromagnetic spectrum, to achieve desirable visual effects.

Materials that are made up of plurality of lenses, arranged in such a way as to refract or reflect one or more of visible, near infrared, near ultraviolet or other forms of light or more generally electromagnetic waves, are used to achieve the desired visual effect and simulated environment and immersive experiences. An example of such a material is a lenticular lens sheet which may have a regular or semi-regular pattern of linear or non-linear shaped lenses, which may be mixed with linear lines within the lens to at least partially reflect or refract light. A typical lenticular plastic sheet is a translucent plastic sheet which has one smooth side while the other side is made of small convex lenses called lenticules that allow the transformation of a two dimensional (2D) image into a variety of visual illusions. Each lenticule acts as a magnifying glass to enlarge and display the portion of the image below i.e., on the smooth side. Other materials that may be used include an array of small spherical lenses, known as a fly's-eye lens array, or a screen consisting of a large number of small convex lenses. Another example of a material that can be used is a linear or array prism sheet.

In accordance with an aspect of the present invention, there is provided a riot shield comprising: a clear body having an outer surface and an inner surface; a first lens sheet having a first polarity disposed over the outer surface; a second lens sheet having a second polarity, disposed proximate the inner surface and the first lens sheet, the first polarity opposite the second polarity, wherein upon a first projector in communication with a first image source projecting an image onto the first lens sheet through the second lens sheet, the image is visible on the first lens sheet but not on the second lens sheet.

In the figures, which illustrates by way of example only, embodiments not part of the claimed invention and embodiments according to the claimed invention are shown.

As noted above, embodiments of the present invention involve display systems and simulated environments that make use of materials made from various arrangements of lenses and other optical materials to achieve distinctive visual effects with applicability in riot shields. These materials utilize the refraction of light and other rays in the electromagnetic spectrum, to achieve desirable visual effects.

It is commonly observed that as a ray of light that enters a material medium at an oblique angle changes its direction. This phenomenon is called refraction. Refraction generally involves a change in the direction of wave propagation due to a change in propagation speed. In the case of light, refraction can be traced to the slowing of the light as it enters the medium, and the speed of light is reduced from its vacuum speed c = <NUM>×<NUM><NUM> to c/n, where n is the refractive index of the medium.

<FIG> depicts an illustration of the law of refraction also known as Snell's law. An incident light ray <NUM> travels from an initial point P<NUM> through a first medium <NUM> such as air, and enters into a second medium <NUM>. The incident ray <NUM> is refracted at the interface <NUM>, so that the trajectory of a refracted ray <NUM> arrives at the point P<NUM>. This is explained by Fermat's principle of minimum time, which states that light will travel from one point to another along a path that requires the minimum time. Thus the angle of incidence θ<NUM> and angle of refraction θ<NUM> must be such as to minimize the optical path length from P<NUM> to P<NUM>. As shown in <FIG>, if the refractive index of the first medium and the second medium are respectively n<NUM> and n<NUM>, then Snell's law states that n<NUM>sinθ<NUM> = n<NUM>sinθ<NUM>.

As noted above, materials that are made up of a large number of lenses, subsets of which are arranged adjacent to one another or in very close proximity in such a way as to refract visible, near infrared and/or near ultraviolet light are known. A typical example is the lenticular lens sheet. Lenticular lens sheets can be made of translucent plastic. Further, some lenticular lens sheets may be smooth one side and while the opposite side may be made up of small convex lenses called lenticules. These lenticules can make an otherwise ordinary two dimensional view of a scene, appear to have a variety of interesting visual effects. For example a lenticule may act as a magnifying glass.

<FIG> is a schematic diagram of a lenticular lens sheet partly in cross-section. As shown, a lenticular sheet <NUM> includes a plurality of lenses or lenticules <NUM>. Images from the lenticular lenses can be viewed within a V-shaped viewing region that corresponds to a viewing angle <NUM>. Viewing angle <NUM> may be small or large. A small viewing angle <NUM> makes the picture very sensitive to change in the sense that a viewer just needs to turn the head slightly and a different set of pictures will be seen. For wide viewing angle <NUM> lenses the viewer can make a relatively large displacement or turn of his head to see a different set of pictures so the change in the viewed is not as sensitive to the displacement in the head's position or orientation. As a result, narrow viewing angle lenses are good for three dimensional (3D) effects and wide viewing angles lenses are good for dynamic prints such as animation, flip, morph or zoom.

A display that presents a three-dimensional image to a viewer without the need for special glasses or other impediments is sometimes referred to as auto-stereoscopic. The first auto-stereoscopic method to appear was the barrier technique, which involved dividing two or more pictures into stripes and aligning them behind a series of vertically aligned opaque bars of the same frequency. It was demonstrated in paintings of by G. Bois-Clair which would appear to change from one picture to another as a viewer walked by.

Later, physicist Gabriel M. Lippmann used a series of lenses at the picture surface instead of opaque barrier lines, and was able to record a complete spatial image with parallax in all directions. The process utilized an array of small spherical lenses, known as a fly's-eye lens array or integral lens array to record and playback the image.

Several scientists simplified the integral lens array by incorporating a lenticular lens array. A lenticular lens sheet consists of a linear array of thick plano-convex cylindrical lenses. The lens sheet is transparent and the rear face, which constitutes the focal plane, is flat. It is also optically analogous to the parallax barrier screen. Nowadays there are specific lens designs for animation, 3D and large formats and mass production techniques.

Conventional materials used for making a lenticular lens sheet are made as clear as possible while maintaining the ability to refract light. Higher transparency of the material is often desirable and in some applications such as printing, clearer and better visual effects can be realized with a high transmittance rate. The material should also be as stable enough to reduce thermally induced distortion so that a sheet of lenticular lenses can be used many contexts such being rolled for shipping or for use in printing presses. A lenticular sheet is usually made from acrylic, polycarbonate, polypropylene, PVC and polystyrene. The lenses may be arranged in an appropriate density, often commonly measured and expressed as lens per inch (LPI).

Typical embodiments of the arrangement of these lenses provides a V-shaped viewing region as depicted in <FIG> and discussed earlier. The image sensitivity to change in the position of the viewer depends on the viewing angle <NUM>. A small viewing angle <NUM>makes the picture sensitive to change in that a viewer just needs to turn the head slightly and a different set of pictures will be seen. For wide angle lenses <NUM> the viewer can make a relatively bigger head turn to see a different set of pictures so the change is not so sensitive. As a result, narrow viewing angle lenses are suitable for three dimensional effects, and for dynamic prints.

The material used for making lenticular lens sheets are preferably stable, so that thermal distortion is reduced, while retaining flexibility so that it can be used in a printing press, and rolled for shipping.

Lenticular lens sheets are typically manufactured using machines or devices custom made for this purpose. One such device is described in published US patent application <CIT>, and entitled "Lenticular lens pattern-forming device for producing a web roll of lenticular lens". The published application describes a lenticular lens and method for manufacturing the lens, in particular as a lenticular lens web, such that finishing operations such as cutting, laminating and various end-use applications of the lens including labeling can be achieved or accommodated in-line with the manufacture of the lens web. The publication also discloses a lenticular pattern-forming device comprising a housing that is rotatable about a central longitudinal axis. The housing has an outer surface having a groove pattern. The groove pattern includes circumferentially and longitudinally extending grooves on the outer surface and the grooves have substantially equal groove widths. The longitudinally extending grooves are substantially parallel with the central longitudinal axis and grooves cover the outer surface of the housing.

Some embodiments of the present invention, that will be described later, relate to the use of lenticular lens sheets to achieve improved camouflage. For example, one suitable type of a lenticular lens sheet has been described in <CIT>. The patent discloses a lenticular sheet that includes a first surface having at least two portions, an opposing second surface, and a plurality of lenticular lenses formed in the first surface. Each portion of the first surface includes a number of lenticular lenses per centimeter that is different from the number of lenticular lenses per centimeter of an adjacent portion of the first surface.

There are several kinds of materials that may be used to make lenticular lens sheets. These include polyethylene terephthalate (PET) which is not amorphous and retains its crystallinity. PET has excellent clarity, good gas barrier properties, and good grease and solvent resistance. Polypropylene (PP) is also suited if the piece is to be finished die cutting lamination or fabrication. Polyvinyl chloride (PVC) which is made by combining ethylene produced by refining petroleum, with chlorine which is produced from rock salt, may also be used.

Specific applications and uses of various types of materials incorporating lenses, methods of making such materials, and articles of manufacture embodying such materials, exemplary of embodiments of the present invention, will be described.

Visual concealment and deception are useful in many contexts, such as hunting where decoys are often setup to attract either the same type of animal or a predator of the animal represented by the decoy. Often these decoys are life size in scale, which means the size of the decoy may be life sized version of a deer or elk. As such, physical decoys are difficult to get in and out of an area.

However, as the lens sheet material is nearly transparent the background colors allow it to blend into any environment in any season, day or night. The need to provide different large physical decoys is avoided as different images can be projected on to the display made of the lens sheet with practically unlimited choice of decoy images to display.

Using two lens sheets of opposing polarity can be used to create an image by way of interlacing as will be described below. Such techniques allow creation of standalone decoys with the projector broadcasting either a stationary decoy or a video of the decoy grazing.

For two sheets to have opposing polarities, if in the first sheet the arrangement of the lenses or lenticules is along a first particular direction, (e.g., horizontally or left-to-right), then in the second sheet having the opposing polarity, the lenses or lenticules would be disposed in a second direction at or about <NUM> degrees (perpendicularly) to the first direction (e.g., vertically or top-to-bottom).

<FIG> is a schematic illustration of an embodiment having a vertically polarized sheet <NUM> close to a projector <NUM>, whereby the projected video image is perceived as a bright horizontal strip <NUM> and may contain ghost images above and below the strip <NUM>. The vertical polarity of the sheet <NUM>, leads to the horizontal alignment of the strip <NUM>.

Adding a second a horizontally polarized sheet <NUM> such that the sheet <NUM> is between the projector <NUM> and the second sheet <NUM> as illustrated, allows the projected video image to be displayed correctly onto the second sheet <NUM>.

The lenses in the second sheet <NUM> run in the opposite polarity (that is, horizontal polarity) thereby creating video image <NUM> on the second sheet <NUM> which remains translucent in areas where the image <NUM> is not projected. Using a black background to record the target or decoy, produces a translucent background around the image portrayed.

The first sheet <NUM> and second sheet <NUM> can be used on a riot shield. When used on a riot sheet, the body of an object holding the riot shield in place (such as a police officer, or a tripod holding the shield in an experimental setup) is hidden when behind the shield from the viewer. Moreover, the location of video image <NUM> on the shield is perspective dependent.

Projector <NUM> may be a large <NUM> lumen or more projector or a handheld <NUM> lumen portable battery powered projector and similar effects are observed. Newer short-throw projectors with internal memory and battery power may thus be used to create a system that may be used by armed forces or the military where video images on shields display non-threatening portrayals of people or items, hiding one or more security personnel or soldiers behind.

In alternate embodiments, the exemplary material may be in front of a military vehicle and may be used to portray a common sports utility vehicle (SUV) or a farm vehicle or animal onto the material thereby deceiving the enemy.

In a variation of the above, a projector such as projector <NUM> may simply broadcast the image or video of a tank (e.g., M1 Abrams tank) or a soldier onto to create realistic decoys as will be illustrated later.

Another related application or embodiment, using any of the techniques above is to project a lenticular image or lenticular video onto the material matching one of the two polarities and frequency of that lens within the sheets, this would allow for standalone three dimensional images or videos onto one or more display sheets.

In the embodiment shown in <FIG>, a first viewer <NUM> and a second viewer <NUM> are on opposite sides of the projector <NUM>. The first sheet <NUM> is closer to the projector <NUM> than the second sheet <NUM> on which the decoy image is presented. Both viewer <NUM> and viewer <NUM> would be able to see the decoy image on the second lens sheet <NUM>. As shown the first lens sheet <NUM> and the second lens sheet <NUM> have opposite polarities.

<FIG> shows a similar embodiment slightly different from the embodiment shown in <FIG> with the polarities of corresponding lens sheets reversed. In <FIG> a first viewer <NUM> and a second viewer <NUM> are on opposites sides of the projector <NUM>. The first sheet <NUM> is closer to the projector <NUM> than the second sheet <NUM> on which the decoy image is presented. Both viewer <NUM> and viewer <NUM> would be able to see the decoy image on the second sheet <NUM>. Again, the first sheet <NUM> and the second sheet <NUM> have opposite polarities, as shown using vertical and horizontal parallel lines respectively.

<FIG>, <FIG>, <FIG>, <FIG> and <FIG> illustrate embodiments that can be used for decoys such as the embodiment illustrated in <FIG>, and in displays as depicted in <FIG>.

<FIG> depicts an embodiment in which the decoy image is projected through a projector lens having a polarized lenticular lens opposite that of the display sheet. A projector <NUM> having a projector lenticular lens <NUM> projects the decoy image onto a display sheet <NUM>. A first viewer <NUM> and a second viewer <NUM> are on opposites sides of the projector <NUM>. The display sheet <NUM> and the projector lens <NUM> have opposite polarities. In the depicted example, projector lens <NUM> has a horizontal polarization while the sheet <NUM> has a vertical polarization.

In a related alternate embodiment, the polarities may be reversed so that the lens <NUM> may have a vertical polarization while the sheet <NUM> may have a horizontal polarization. Both viewer <NUM> and viewer <NUM> would be able to see the decoy image.

<FIG> depicts an embodiment in which the decoy image is projected onto a display sheet having lenses on both sides but with opposite polarities. A projector <NUM> having a projector lens <NUM> projects the decoy image onto a display sheet <NUM>. However, in this embodiment, the projector lens <NUM> does not have a polarized lens. A first viewer <NUM> and a second viewer <NUM> are on opposites sides of the projector <NUM>. The display sheet <NUM> has lenses on both sides but with opposite polarities. Viewer <NUM> would be able to see the decoy image but viewer <NUM> may or may not be able to see the decoy image depending on the polarity and the viewing angle.

In embodiments having a second projector on the side of the viewer <NUM>, if the image includes a background landscape and a decoy foreground image, the decoy image is only viewable on the opposite side i.e., by viewer <NUM>, while the background landscape may be seen on both sides. On the side where the decoy image is visible the background can only be seen behind the decoy image, from a tight angle, whereas the background is visible on the opposite side (viewable by viewer <NUM>) across a very wide angle but the decoy image is not visible on that side.

This visibility of an image from one projector on both sides only occurs when the two lens sheets of opposite polarity are in very close proximity to each other or touching.

Moreover, in embodiments having a second projector on the side of the viewer <NUM>, visibility of an image from one projector on both sides further requires the polarity to be set up so that side showing the background only, has its lenses disposed vertically (up-down) whereas the side that shows both the decoy image and the background (within a tight viewing angle) has its lenses disposed horizontally (left-right).

Using this above techniques, a military soldier may place decoy soldiers around a defensive position to make adversaries perceive a larger force. If combat occurred the adversaries would have many more targets to select from thereby protecting the actual soldiers and if the decoy was hit the bullets would likely go right through the material and remain intact and the decoy would appear uninjured thereby drawing further fire away from the real soldiers.

A simplified embodiment of the above scenario is schematically illustrated in <FIG> which depicts two decoy sheets <NUM>, <NUM>. The decoy sheets <NUM>, <NUM> are used respectively to have decoy images <NUM> of soldiers projected thereon from a projector <NUM>, in order to create the illusion of a much larger force than is actually present.

While the image may be viewed on either the smooth or lens side of the material on the second sheet <NUM> that interlaces the image, better or even optimum results occur when viewing the image with the lens side facing the viewer <NUM> as shown. This could be improved with anti-reflective coatings on the smooth side and these anti-reflective coatings on the lens side may also improve results. The smooth side facing the projector is also perceived better if the viewer is on the side of the projector <NUM> as the smooth side helps reflect the image back towards the projector side.

The projector <NUM> can be on the side as the viewer <NUM> facing away from the viewer onto the material (such as one of decoy sheets <NUM>, <NUM>) which is further away from the viewer in relation to the projector <NUM>. The material on sheet <NUM> closest to the projector <NUM> would have to be shorter than sheet <NUM> to allow the viewer <NUM> to see over sheet <NUM> and see the decoys on sheet <NUM>.

Improvements of having lenses manufactured with the opposite polarity being on both sides of each sheet so there is no smooth side on either sheet - that is, the first sheet would have lenses on both sides running up and down whereas the second sheet would be opposite of the first sheet with lenses on both sides running left to right. These polarities are interchangeable between the two sheets as long as they are opposite from one another.

Using larger decoy sheet material, images of larger objects such as armored vehicles and tanks may be broadcast. The larger decoy sheet material may be attached to a small golf cart. Alternately, the larger material may be attached to balloons in order to broadcast images of an attack helicopter.

Placing very large decoy sheets around an installation would provide for a large static or moving display of vehicles, soldiers and aircraft which may deceive an enemy into believing that there is a much larger defensive or offensive force around the installation, with minimal cost to create and operate these decoys.

Other exemplary embodiments involve a curved set of lenses, shaped like a cylinder, having lenses on one or both sides. In one specific embodiment, on the side of the cylinder facing the projector the lenses are arranged in a first polarity while on the opposite side the lenses are arranged with an opposite polarity to the first set of lenses. This creates an element of depth, being able to see part of the image on the right side of the curve and as viewer moves around to the left side, the viewer can then view that part of the image could not be seen from the right. Both lenses may be curved in the same direction or the first lens may be flat as will be described in detail below. The curve may be concave such as on new televisions and IMAX screens which helps reduce reflections on the screen having lenses.

In a related embodiment, lenses of opposite polarity are manufactured into the same piece of material so one side of the material the lens runs up down and the other side lens runs right to left. No other lenses are needed to attain an image interlaced onto this combined lens material nor is any distortion required to fix the image or video on the material as there is no separation between the two lenses to allow for distortion. This single piece of material may be manufactured as a flat sheet, curved or in any geometric shape providing a projection screen that may have a number of curved or angled viewable surfaces such as a cube or pyramid. More than one projector may be required to project onto surfaces of a shaped screen to provide an image or video over a partial shape of the material or over the complete shape of the material.

<FIG> depicts an embodiment in which an image, which may be a decoy image, is projected on curved set of lenses, shaped like a cylinder. A projector <NUM> projects the image onto a cylindrical display sheet <NUM> which has a front half that is polarized opposite the back half as shown. In the depicted embodiment, the front half is horizontally polarized while the back half on which the projected projects in the image initially is vertically polarized. A viewer <NUM> views the image formed on the front half of the cylindrical display sheet <NUM>.

<FIG> depicts an embodiment in which an image, which may be a decoy image, is projected on curved set of lenses, shaped like a half cylinder. A projector <NUM> projects the image onto a half cylindrical display sheet <NUM> whose lenses are polarized opposite that of a second sheet <NUM> that is closer to the projector <NUM> as shown. Although in <FIG> a flat second sheet <NUM> is shown, in other embodiments, sheet <NUM> may be curved as well. A first viewer <NUM> views the image formed on the front half of the cylindrical display sheet <NUM>. A second viewer <NUM> also sees the same image formed the half-cylindrical display sheet <NUM> if sheet <NUM> does not obstruct viewer <NUM> from viewing sheet <NUM>.

<FIG> depicts another embodiment in which an image, which may be a decoy image, is projected on curved set of lenses, shaped like a half cylinder. A projector <NUM> projects the image onto a half cylindrical display sheet <NUM> which is formed by placing two half cylindrical display sheets together whose lenses are polarized opposite one another as shown by the vertical and horizontal lines.

A first viewer <NUM> views the image formed on the outer side of the half cylindrical display sheet <NUM>. A second viewer <NUM> also sees the same image on the inner side of the half-cylindrical display sheet <NUM>. As noted earlier with reference to <FIG>, visibility of an image having a background and a decoy foreground, from a single projector, on both sides of display sheet <NUM> only occurs when the two lens sheets making up display sheet <NUM> are of opposite polarity and in very close proximity to each other or touching. Moreover, in embodiments having a second projector on the side of the viewer, visibility of an image from one projector on both sides further requires the polarity to be set up so that side showing the background only, has its lenses disposed vertically (up-down) whereas the side that shows both the decoy image and the background (within a tight viewing angle) has its lenses disposed horizontally (left-right).

<FIG> depicts another embodiment in which an image, which may be a decoy image, is projected on a curved lens sheet made up of a set of curved lenses, shaped like a half cylinder. A projector <NUM> having a polarized projector lenticular lens <NUM> projects the image onto a cylindrical display sheet <NUM>.

The lenses on display sheet <NUM> and the projector lenticular lens <NUM> have opposite polarities. A first viewer <NUM> views the image formed on the front half of the cylindrical display sheet <NUM>. A second viewer <NUM> also sees the same image formed on the half-cylindrical display sheet <NUM>.

In alternate embodiments, that will be discussed below, displays may be shaped differently and may even have a three dimensional configurations having multiple display surfaces.

<FIG> depicts a schematic illustration of an exemplary embodiment in which a viewer <NUM> views an image projected on to a spherical display <NUM> from a projector <NUM>. The viewer <NUM> is on one side of the spherical display <NUM> while the projector <NUM> is on the opposite side of the projector <NUM> as shown. The back hemisphere of the spherical display <NUM> facing the projector <NUM> or at least a portion thereof, would have the opposite polarity of the front hemisphere (or at least a portion thereof) of display <NUM> where the image appears.

<FIG> depicts a schematic illustration of another embodiment in which multiple projectors are involved, and viewers view different images depending on their vantage point. A first viewer <NUM> views an image projected on to a display surface <NUM> from a first projector <NUM>. A second viewer <NUM> views another image projected on to another display surface <NUM> from a second projector <NUM>. There would be lens material in between projector <NUM> and display surface <NUM> of the opposite polarity of display surface <NUM>. Similarly there would be lens material between projector <NUM> and display surface <NUM> of the opposite polarity of display surface <NUM>. Alternately the lenses of the projectors would have lenticular lenses of the opposite polarity so that the projector lenticular lens polarity on projector <NUM> would be opposite of display surface <NUM> and the projector lenticular lens polarity on projector <NUM> would be opposite of display surface <NUM>.

<FIG> depicts a schematic illustration of yet another embodiment in which images or video are displayed on numerous sides of displays. One or more projectors <NUM>, <NUM> can be used. Projector <NUM> projects images on to display <NUM>. Different sides of display <NUM> such as side <NUM> and side <NUM> can display different images. Display <NUM> may be polyhedron in shape in general, and a tetrahedron in particular as shown. Projector <NUM> projects images on to display <NUM>. Different sides of display <NUM> can display different images as shown. Viewers <NUM>, <NUM>, and viewers <NUM>, <NUM> can see images in their fields of view projected on display <NUM> and display <NUM> respectively. As would be appreciated, there is lens sheet material (not shown) of opposite polarity between the projector and the surface where images are portrayed. Alternately, the lenses of the projectors would have lenticular lenses of the opposite polarity as described just above.

<FIG> depicts a display with a complex shape in which multiple projectors are used with many potential applications in advertising, art, architecture and the like. An exemplary complex display <NUM> displays images projected under, over or from the side of its surfaces. Display <NUM> may be polyhedron in shape. The projections may also emanate from within the display <NUM>. Viewers <NUM>, <NUM> are thus able to see a variety of images on the many surfaces <NUM> of display <NUM>, as projected by projectors <NUM>, <NUM>, <NUM>, <NUM> and <NUM>. Again, the skilled reader would appreciate that there is lens sheet material (not shown) of opposite polarity between the projector and the surface where images are portrayed. Alternately, the lenses of the projectors would have lenticular lenses of the opposite polarity as described above with reference of <FIG>.

In another exemplary embodiment illustrated in <FIG>, a display system with two projectors disposed a first fixed distance apart, to face each other project their respective images towards one another. Two lens sheets having opposite polarities are disposed, a second fixed length apart between the projectors. The second length is shorter than the first length as the lens sheets would be disposed in between the projectors.

In the specific embodiment of a display system <NUM> depicted in <FIG>, a projector <NUM> connected to a computer <NUM> and another projector <NUM> connected to another computer <NUM> are placed facing each other about <NUM> feet apart. This distance can be varied and the specific distance of twelve (<NUM>) feet noted above is only exemplary. A first lens sheet <NUM> and a second lens sheet <NUM> having their respective lenses arranged in opposite polarities are placed in between the two projectors <NUM>, <NUM> about two (<NUM>) feet apart from each other. This distance can be varied and the specific distance of two (<NUM>) feet noted above is only exemplary.

In operation, as shown in <FIG>, when projecting the image <NUM> from computer <NUM> using the projector <NUM>, the projected image <NUM> would first go through lens sheet <NUM> closest to projector <NUM> and interlace onto lens sheet <NUM> as shown.

Simultaneously, as shown in <FIG>, when projecting image <NUM> from computer <NUM> using the projector <NUM>, the projected image <NUM> would first go through lens sheet <NUM> that is closest to projector <NUM> to interlace onto the farther lens sheet <NUM> as shown.

As may be appreciated, in the specific depicted arrangement, a user <NUM> in <FIG> would be able to see the image on lens sheet <NUM> but not the same image <NUM> on lens sheet <NUM>. Similarly, a user <NUM> in <FIG> would be able to see the image <NUM> on lens sheet <NUM> but not the same image on lens sheet <NUM>.

An interesting application of the above embodiment as depicted in <FIG> is simultaneous video broadcasting. Video sequences or movies projected would behave in the same manner as the images, i.e., user <NUM> would be able to see a video sequence projected on lens sheet <NUM> but user <NUM> would not be able to see the video on lens sheet <NUM> from where he or she is positioned. Similarly, user <NUM> would be able to see the video projected and interlaced on lens sheet <NUM> but will not see the video sequence on lens sheet <NUM> from where he is she is positioned or situated.

It was found by the inventor of the present invention that when lens sheets are placed two (<NUM>) feet apart, if a viewer changed his or her viewing angle or perspective, the image would shift on the lens sheet providing an element of depth that was specific to the viewer. The shifted image viewed would be different for a second viewer and similarly again different for each person on that same side of the lens sheet. This effect was more apparent when the image or video was on the horizontal polarity. The second motion picture or movie playing on the opposite side in the vertical polarity was slightly different as there was more perceived movement up and down in relation to the viewers distance changing between the viewer and the lens - i.e., as the viewer got closer, the image would move up on the lens in relation to the viewer's distance.

The above finding provides a new use for embodiment of <FIG> and confirms the holodeck application of the embodiments of <FIG> that illustrate immersive experience room for multiple people providing different perspectives for each.

The element of depth and perspective comes about from the two lens sheets <NUM>, <NUM> of opposing polarity having some gap or distance between them (e.g., two feet). This is also true of one projector broadcasting through both lens sheets set apart from each other (gap of inches or feet) - the greater the gap between the lenses the more movement occurs with a viewer's changing perspective.

When the two lens sheets are held together, the image had no movement change when based on the viewers' perspective. Further, when using two projectors from either side each lens would show a ghost image from the closest projector over the image or movie from the second.

Tighter configurations of lenses on a lens sheet, which may have different angles, such as in cylindrically shaped sheet <NUM> in <FIG>, increases the clarity and viewing angle of the video and reduces the bands of light and prism (rainbow) effect which are seen when a larger configuration of lenses is used.

Another display system, exemplary of an embodiment, is depicted in <FIG>. The display system includes a projector <NUM> and a mirror <NUM> disposed between a first lens sheet <NUM> and a second lens sheet <NUM>. This arrangement allows for more compact display system housing all the components. Such an arrangement permits components behind lens sheet <NUM> such as projector <NUM> to be hidden from the viewer <NUM> (around a corner).

Lens sheet <NUM> and projector <NUM> may be substituted with a projector having a projector lens or projector lens cover thereon. As will be appreciated by a person of skill in the art, the projector lens or cover would have a polarity opposite that of lens sheet <NUM> so as to permit interlacing of the projected sub-images. The lens sheet <NUM> may also utilize different geometric shapes as discussed in relation to earlier described embodiments.

In the above embodiment, a distortion of the aspect ratio may be observed on the displayed image on lens sheet <NUM>, when a video image is projected from projector <NUM>. This may be due to the distance between the two materials with the mirror bounce creating a larger distance. To correct such distortions, horizontal and vertical ratio of the video being projected may be changed as will be described later.

In yet another variant, exemplary of another embodiment, a display system as depicted in <FIG> uses a plurality of projectors <NUM>, <NUM> connected to corresponding image sources <NUM>, <NUM> respectively, and a mirror <NUM> in between a lens sheet <NUM> and lens sheet <NUM>. This allows for dual viewing in a manner similar to the embodiment of <FIG>.

Viewer <NUM> sees the image or video from projector <NUM> without seeing the image from projector <NUM> while viewer <NUM> sees the image or video from projector <NUM> without seeing the image from projector <NUM>. As may now be will be will be appreciated by those skilled in the art, the lens sheet <NUM> and the lens sheet <NUM> have opposite polarities.

Another exemplary embodiment involves immersive virtual reality (VR) systems that are known to allow users to interact in virtual environments, where presence is limited to the virtual world. Movies and scientific literature have suggested several VR interfaces that enhance presence of users in a virtual environment (VE), for example, the holodeck on the popular television series Star Trek™. Some of these immersive environments inspired research into displays where the user cannot tell real from virtual.

In embodiments not part of the claimed invention, as a viewer moves, the image or video on a lens sheet display changes, but based solely on the location of the viewer relative to the lens sheet display.

Companies such as Microsoft are working on a Holodeck type room to immerse someone into a simulated environment within the room providing video on the walls that are projected with the correct perspective for the viewer's location within that environment. Typical approaches are geared towards a first person, assumed to be a single user, whose head is tracked by a camera and the images or video are moved or spatially translated in relation to the head of the subject person to retain the correct perspective. In other words, a video camera tracks the first person's head and modifies the environment for the correct perspective of this viewer.

While this allows the first person to attain the correct perspective, any other persons in the room that are not near the first person would get an unrealistic perspective. The perspective of other persons would be off or incorrect if the other persons are not near the first person.

Exemplary of embodiments do not track the viewer. Rather, it is a property of the lens sheet material that, when utilized in the manner as depicted and described herein, provides different perspectives depending on the location of the viewer. Tracking of the user's movements is avoided, in sharp contrast to existing VR systems. One of the most intuitive ways of moving through such a scenario as well as through our real world is to perform real walking.

This is important in creating realistic looking 3D objects, holographic like displays or virtual or augmented reality.

Using materials exemplary of embodiments, such as lenticular lens sheets as described above, in a virtual reality room, and broadcasting from the other side of the wall from the observers with numerous projectors providing unique perspectives which can only be seen from particular observation points, multiple users could experience the same virtual reality environment without a camera tracking one user. The projectors may also be inside the room, for example, on the roof or suspended above the people or in other areas within the room. The projectors broadcast images onto the lens material placed on or in front of the walls which may be transparent, translucent or solid walls. If the walls are transparent then the projectors may be placed behind the walls.

Each user would have a perspective dependent view that depends on the viewers physical location and orientation which changes as each user moves move through the room due to the nature of the lenticular lens that allows them to create 3D images, and the many different projectors of the scene.

This is depicted in <FIG>. The virtual reality room in <FIG> depicts different users <NUM>, <NUM> looking at the same wall <NUM> made of a lenticular lens sheet. Projectors <NUM>, <NUM> project or broadcast on to the wall of the virtual reality room. The user <NUM> views the image <NUM>, while user <NUM> views the image <NUM> on the same wall <NUM>. Image <NUM> and image <NUM> may be perceived as 3D images.

In <FIG> the projectors <NUM>, <NUM> could be behind transparent wall <NUM> with a lens sheet in front of the projectors and second lens sheet of the opposite polarity on the wall <NUM> as shown. The transparent wall <NUM> may be made of glass or Plexiglas. The projectors <NUM>, <NUM> may also be arranged within the room with a lens in front of the projector and a second lens of the opposite polarity on the wall which is either transparent, translucent or solid. Mirror bounce techniques could also be used as described previously for <FIG>.

New projectors may be developed for the display system as shown in <FIG>. As illustrated <FIG> depicts different users <NUM>, <NUM> looking at transparent or semitransparent wall <NUM> made of a lenticular lens sheet. Projectors <NUM>, <NUM> project or broadcast on to the wall <NUM> of the virtual reality room. The user <NUM> views the image <NUM>, while user <NUM> views the image <NUM> on the same wall <NUM>. These new projectors <NUM>, <NUM> have polarized lenticular lenses built into their respective projector lens thereby removing the need for the first sheet to be placed in front of the projector, thus allowing for the projector to transmit the image or video directly onto the second sheet in the form of wall <NUM> having the opposite polarity. An improvement may be to have the second sheet with the same polarity of lenses manufactured on both sides of the sheet or placing two sheets together with the same polarity. Mirror bounce techniques could also be used as described previously for <FIG>.

In experiments, using different size lenses between the first lens and the second of the opposite polarity still functioned. However the larger lens polarization if used on the first lens closest to the projector could be perceived on the second lens if the lenses were close to each other.

In an alternate exemplary embodiment, two lenses of opposite polarity are placed close together or on top of one another to create a translucent screen for either forward or rear projection which can be viewed on either side.

In one exemplary embodiment illustrated in <FIG>, a cylinder configuration to display two different images or video streams of the front left and front right side on the same lenticular lens sheet 2304a. A pair of projectors 2302a, 2302b which may be the smaller <NUM> lumen portable projectors are used. A first viewer <NUM> and a second viewer <NUM> view different images or videos as they are at different locations relative to the cylindrical display <NUM> having a first lens sheet 2304a and a second cylindrical sheet 2304b. The two lens sheets 2304a, 2304b have opposite polarizations. The lens sheet 2304b first receives the projected image from the projectors 2302a, 2302b which are then interlaced onto lens sheet 2304a. Viewer <NUM> sees the image or video projected from projector 2302a and viewer <NUM> sees the image or video projected from projector 2302b.

The embodiment demonstrates that as a viewer moved from one side of the cylinder to the other that you would see the two different views. The same image or movie may be shown on both the left side and right side but with the correct perspective for the viewer such as seeing the left side of a person on the left side and the right side of the same person on the right side leading to a simulated three dimensional effect. This technique of using two or more projectors to create multiple perspectives that are viewer location dependent also works on non-curved (flat) lenses.

Photographs with a flat black backdrop show that when projected, black background does not show up on the material or sheet 2304a. This aspect is important when simulating a decoy onto the material such as a soldier, the background does not give away that it is a decoy.

It is to be noted that projected images on lens sheets 2304a, are above the lower piece of the light bending material in behind (the sheet 2304b closest to the projectors 2302a, 2302b). Once this feature is pointed out, it becomes very confusing for a viewer to understand the optical principles involved, which adds to the Sci-Fi holographic display effect people have hoped for.

The two projectors 2302a, 2302b are both from the same manufacturer. Projector 2302b includes a short throw lens allowing it to be much closer to the material on sheet 2304b in order to provide the same size image as projector 2302a.

In a slight variation of the embodiment depicted in <FIG>, only one projector may be used with one image of a person taken from the front, to simulate the holographic effect without the need for multiple projectors. While the image viewed is static, the movement of the viewer and the way the image follows the viewer on the material as the viewer moves left to right (more so when on the horizontally polarized lens sheet) or closer and farther (more so when on the vertically polarized lens sheet) makes it appear like a three dimensional (3D) object.

Multiple large pieces of the lens sheet material may be used to create life sized rendering of images. For example, <FIG> depicts a system <NUM> for simulating a soldier in uniform using the perspective dependent nature of the lens sheet material.

A projector <NUM> projects a video or sequence of images through a first lens sheet material <NUM>. In the depicted embodiment, five (<NUM>) large pieces of secondary lens sheet material <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, each in opposite polarity to lens sheet material <NUM>, are used to increase the viewable angle.

A black backdrop may be used to hide the background while filming a person wearing a uniform so only the person is shown on the material. Viewers <NUM> would perceive the virtual decoy soldier <NUM> as a military guard observing the area, even when the viewers <NUM> walk around to different angles.

If the virtual decoy soldier <NUM> is intended to appear to be defending a location and shooting a gun, it is desirable to have the enemy target the virtual decoy <NUM> instead of real or actual combatants. One benefit to the illustrated system <NUM> is that bullets should go right through the lens sheet material and have little effect on the material or the video projection. The virtual decoy soldier would still appear to be defending and the enemy would continue to try to hit it, unless the projector is hit. The projector could be protected and placed out of the way using the mirror bounce technique.

Projector <NUM> may be implemented using a small battery powered, portable <NUM> lumens projector. An internal <NUM> GB memory on the projector <NUM> may store video or sequence of images to be projected. This avoids the need for an external device such as computer, which leads to fewer pieces of hardware and a compact size, which is important to soldiers who may have to carry these virtual decoys. In one specific embodiment, projector <NUM> was rated to have estimated battery life up to <NUM> hours and often provided close to <NUM> hours, and the projector included two built in <NUM> watt speakers.

One of the issues when viewing these demonstrations is the reflection caused by the pieces of lens sheet materials <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. This may be overcome with antireflective coatings but even the addition of a simple bug screen to mitigate much of the reflection without hindering the projected image too much.

Advantageously, a soldier can both hide behind the set of lens sheets for concealment purposes and project a different image on the sheets toward the viewer for deception purposes, as long as he or she is not between the projector and the first or secondary lenses.

In the depicted embodiment of <FIG>, each of the five pieces of material <NUM>, <NUM>, <NUM>, <NUM>, <NUM> are all in the horizontal polarization, so that what is viewed is a table below and wall behind and above or the window stretched down as the soldier moves to that side of the material. This provides insight into the best polarization to use for use with soldiers (vertical) hiding behind it so that the background on the material does not appear as an anomaly.

In some situations it may be desirable to have a virtual soldier displayed on a riot shield rather than just hiding behind it, allowing it to show the background. When opening a door, persons on the other side will know something is coming through the door. To stop enemy soldiers from reacting aggressively, such as reaching for their guns, one may project one of their soldiers onto the shield or the janitor or someone familiar. This allows the first person in, extra safety and extra time to observe the room to determine threats from friendlies. This may also be true of soldiers accidently making a noise outside, stepping on a branch and drawing attention to there location. By portraying an animal such as a dog or racoon onto the material, the viewers will be deceived into thinking a non threat created the noise to continue to hide the soldier or soldiers behind it.

In other embodiments, it is possible to place a small polarized lens directly over a projector lens with the opposite polarization to the viewable lens sheet. This requires lens sheet with very fine lenses.

Many different applications of exemplary embodiments of a display system using the illustrated and demonstrated techniques, and combinations multiple perspective projections to provide 3D holographic style videos or images onto a riot shield or virtual military decoys have many uses in civilian and military applications. It is readily apparent that the invention described herein has potentially wide commercial applications such as advertising, entertainment, architecture, communication, social interaction, home security and law enforcement.

In many of the exemplary embodiments described above, it may be observed that the image on the second lens sheet may contains distortions or artefacts that are viewed by the target observer. These distortions may be reduced, minimized or eliminated with an appropriate compensatory pre-distortion at the image source (e.g., a computer) before the image is projected by a projector.

An exemplary embodiment for reducing the distortion is shown in <FIG>. An image source <NUM> in the form of a laptop computer provides a pre-distorted image <NUM> to projector <NUM>.

Image <NUM> is made much wider on the computer so the viewable logo image <NUM> displayed on the material or on lens sheet <NUM> appears corrected. It will be noted that the pre-distored image <NUM> appears oval or elliptical while the corrected image <NUM> is circular as intended.

This is due to the inherent distortion in the system of <FIG>, which would have distorted a clean circular image, now instead has the effect of undistorting the pre-distorted elliptical image <NUM>. In this example, a mirror bounce technique is used to provide a compact setting for the photo image.

Other exemplary embodiments of the present invention include riot shields. <FIG> depicts a riot shield 2600a having a clear shield body 2602a. In such an embodiment where there is little distance to work with between the person holding the shield using handles 2608a, 2610a and the clear shield body 2602a, a first piece of lens sheet material 2604a on the clear riot shield body is in close proximity to the second lens sheet 2612a in the opposite polarity in the vertical center of the shied body 2602a, no correction is required for the aspect ratio, and a projector 2606a can be much closer to the material. However, this may create a gray colored background zone visible from the front appearing behind the decoy or projected image if a black backdrop was used to remove the background during filming. This Gray colored background only appears in the center of the shield between the two handles 2608a, 2610a where the two pieces of lens sheet material 2604a, 2612a are closest to each other. Projectors with a shorter throw distance could be much closer, e.g., attached to longer handles, to achieve the same effect.

The reason the material on the riot shield shows the background so well is that the lens polarization is vertical, this up/down polarization hides a person (a vertical human) in behind while retaining the horizontal elements such as the table edge, wall edge and window frames. The lens sheet refracts the horizontal and hides the vertical.

In riot shield 2600b shown in <FIG> having handles 2608b, 2010b and a clear shield body 2602b, a first piece of lens sheet material 2604b is formed on the clear shield body 2602b itself while the second lens sheet 2612b in the opposite polarity is formed on the projector lenticular lens of projector 2606b. Projector 2606b can be much closer to the lens sheet material 2604b. Projector 2606b is a short throw projector and the distance could be much closer. This configuration removes the gray background that can be present in <FIG> and allows the actual background colors behind the person holding the shield to be displayed as there is sufficient distance between the lenses.

In riot shield 2600c shown in <FIG> having handles 2608c, 2010c and a clear shield body 2602c, a first piece of lens sheet material 2604c is formed on the clear riot shield body 2602c itself while the second lens sheets 2612c, 2616c in the opposite polarity (of material 2604c) are formed on the projector lenticular lenses of projectors 2606c, 2614c respectively. Projectors 2606c, 2614c can be much closer to the lens sheet material 2604c. Projectors 2606c, 2614c are short throw projectors and again the distance could be much closer, e.g., attached to longer handles 2608c, 2610c, to achieve the same effect. This configuration removes the gray background that can be present in <FIG> and allows the actual background colors behind the person holding the shield to be displayed as there is sufficient distance between the lenses.

In order to project a larger image on this vertical polarization, the video was rotated <NUM> degrees on a computer, then the projector was turned <NUM> degrees to correct for the projection as the aspect ratio on this projector and most others is <NUM>:<NUM> (<NUM> wide x <NUM> high). By turning the projector by <NUM> degrees, it is possible to utilize the longer side (<NUM> units of length) as the height and the shorter side (<NUM> units of length) as width.

Lenticular lenses may be used to create a simulated three dimensional image of a special image that appears to be placed behind and against the back of the sheet. The images are not physically displayed directly behind the sheet but rather the lenses create an optical effect or optical illusion, in which the image appears to be beyond the back of the lenses or the sheet, to an observer.

<FIG> depicts an arrangement used to create a display with a simulated three dimensional effect. A lens sheet <NUM> made up of a number of lenticular lenses <NUM> is used to create a display with a simulated 3D effect. The lenticular lenses <NUM> receive light from a projector of a special produced image <NUM> which would go through an opposite polarized lenticular lens prior and corrected with pre-distortion as shown in <FIG>. The special produced image that is projected would utilize the lenticular printing effect to simulate the motion as it is done with printed lenticular sheets with the printed lenticular image or video ending up behind and against the smooth backside <NUM> of the sheet <NUM> as shown in the exemplary embodiment depicted in <FIG>.

In an exemplary embodiment of the present invention, a projection device or projector may be used to project an image or video sequence through a first lenticular lens sheet and a second lenticular lens sheet. The first lenticular lens sheet may contain a plurality of lenticular lenses or convex lenses that run in the same parallel direction, for example left to right, giving the sheet a first polarity.

At a farther distance from the first sheet, the second lenticular sheet containing another plurality of lenticular lenses or convex lenses may be placed or disposed. The lenses in the second sheet run in the opposite direction to the first that is up and down, giving the second sheet a second polarity opposite to the polarity of the first sheet.

The image projected through the first sheet may be stretched due to the proximity of the first sheet to the projection source. The distance between the first sheet and the second sheet can be offset by adjusting the image or video within the projection to compensate for the stretching, so as to make the image on the second sheet appear at a normal aspect ratio.

In one specific embodiment, a projector may allow the projected image to be seen on a background of any color. In vehicles, the pillars on the windshield have widened to meet crash test requirements as well as housing air bags. These wide pillars have in turn created large blind spots in vehicles.

<FIG> depicts a simplified diagram of the interior of a vehicle <NUM> having windshield <NUM> and pillars <NUM>. A short throw projector <NUM> on the interior roof of a vehicle broadcasts images and video onto a first sheet <NUM> which could be close to the lens of the projector <NUM> and not in the way of the field of view for the driver, which is then projected onto a second sheet <NUM> covering the pillar <NUM>.

As will be appreciated, another short throw projector <NUM> may be disposed proximate the first short throw projector <NUM>, to project to a sheet <NUM> first and then to another sheet <NUM> on the opposite side of the interior of vehicle <NUM> in a similar manner, as depicted.

The images and video that are broadcast onto the sheet <NUM> are captured by one or more cameras (not illustrated) mounted on the vehicle <NUM> recording the exterior environment. This provides the driver of vehicle <NUM> with a video view as if through the solid pillar <NUM>.

As can be seen in <FIG>, the integrated view of the visible portion of a triangular object <NUM> seen through windshield <NUM>, together with the image <NUM> of an otherwise invisible portion of the object <NUM> obstructed by the pillar <NUM> from the driver's view, but captured by the camera and displayed on sheet <NUM>, creates the illusion of a driver seeing through the solid pillar <NUM>.

Currently special reflective materials are needed to allow the image or video to reflect the image to been seen rather than being washed out. White is the most typically used color. However, this has the drawback of limiting the look of the interiors of vehicles. Using the technology described in <FIG> any color could be used on the pillar <NUM> behind the second sheet <NUM>.

The Jaguar Land Rover Limited company had demonstrated broadcasting, the hood of one of its off-road vehicles, a video on of what was directly ahead of the vehicle - as if the driver could see through the hood of the vehicle - to provide a less obstructed view for increased safety. In a demonstration of what the company called Discovery Vision Concept, a front-facing camera is used to capture images which are then projected on the lower portion of the windshield so the driver can simulate seeing through the hood. A drawback of this approach is that the color of the hood would have to be within a narrow range for optimal image/video reflection from the projector in daylight.

By using techniques such as that depicted in <FIG>, the color of the hood may be made any arbitrary color and still retain a good reflection for the driver to see the image or video in daytime. Similar applications of this technology may be employed in cockpits in aircraft, bridges of ships, and control towers at airports.

Broadcasting an image or video onto a wall usually requires a white or retroreflective surface that is usually white. Variations of the exemplary embodiment as shown in <FIG> may be utilized via a projector or series of projectors so that large images or videos could be displayed on interior or exterior walls, roof's, floors or other backgrounds of arbitrary color.

Broadcasting images from a projector onto a transparent surface often does not yield favorable results. Typically there is a ghost like image displayed on the transparent surface. By utilizing technique, exemplary of embodiments as described just above, improve images may be displayed on glass. The second lens sheet may be disposed on the glass to yield a much better image or video sequence with minimal ghosting.

In a variation of the above, boardrooms may be designed using windows as display screens as needed instead of requiring a dedicated screen or a television set or monitor for presentation.

In a related application, very large scale video images may be displayed across a hotel that has many windows, which could allow for inexpensive mega screen advertising by placing many small projectors on the outside or inside of the hotel.

In many of the exemplary embodiments described above, one or more projectors were used to generate the image or video that is displayed on a lenticular lens sheet. However, the inventor has discovered other embodiments in which static or passive images are used to simulate the motion parallax effect - that is, changes in the perceived image of an object over time that changes with observer movement. In this exemplary embodiment, static photos, artwork, logos, images, drawing as well as video display screens may be used.

<FIG> depicts a simplified diagram of components of a passive display system, exemplary of an embodiment not part of the claimed invention, for simulating motion parallax using the perspective dependent nature of lens sheets. A picture frame <NUM> has an edge <NUM> which is at or about <NUM> above the image matte <NUM>. A double sided lenticular lens sheet <NUM>, not necessarily drawn to scale, depicts vertically polarized lenticular lenses. A single sided lens sheet is a typical lenticular lens sheet as depicted in <FIG> where one side has a smooth flat surface while the other side contains convex lenses. A double sided lenticular lens sheet contains lenticules or convex lenses on both sides.

Ideally lenticular lens sheet <NUM> would be manufactured as one integral piece. However, two lenticular lens sheets may be disposed or placed back to back, along the dotted line shown in <FIG>, to form the lenticular lens sheet <NUM>. An adhesive may be used to adhere the backs of the two lens sheets together. The adhesive is preferably a clear permanent adhesive. However, in some specific embodiments, the adhesive may be water. When two single sided lenticular lens sheets are used, corresponding ones of the lenses such as lenses 3110a, 3110b in each sheet are aligned in the same polarity, i.e., vertically to simulate movement side to side, or horizontally to simulate up and down movement.

<FIG> depicts lenticular lens sheet <NUM> placed on top of the frame <NUM>. Lens sheet <NUM> sits at or about <NUM> above the mounting board or image matte <NUM>. This distance can be varied for greater or less effect as desired. The viewer <NUM> from different vantage points <NUM>, <NUM>, <NUM> perceives one of the three locations of the image of the animal appearing staggered on the matte <NUM> through the lens sheet <NUM> depending on their side to side vantage point. If the lenses were configured in the horizontal polarization the image will move up and down depending on the distance or changing height of the viewer <NUM>.

The effect is similar on video display screens, such as smart phones, tablets, computer monitors, television screens where the lens sheet should be elevated away from the screen similar to the depiction in <FIG>.

The two lenticular lenses 3110a, 3110b (or one double sided lens) could be curved out towards the viewer in the middle so there is greater distance from the image in the middle, thus greater perceived movement in the middle versus the sides of the image. It could also be curved in towards the middle so there is more perceived movement on the sides versus the middle.

Lenses with different LPI ("lens per inch" or "lines per inch") produce different frequencies of movement. The two lens sheets depicted in <FIG> are of the same LPI but in other embodiments, the can be different from each other to vary the visual effect.

<FIG> depicts another double-sided linear lens sheet <NUM>, made by placing two linear lens sheets back to back, similar to lens sheet <NUM> but having a horizontal polarity. In this arrangement, an object close-up appears in the correct location but at a particular distance d, the viewed object at location <NUM> will appear in the mirror image.

Due to the polarization, the effect is to reflect light rays <NUM> into reflected rays <NUM> by the back-to-back plurality of lenses <NUM> so that they converge at location <NUM>. Thus objects running in the same polarity can be removed or reduced from view, particularly those in the zone where viewed objects begin to appear in mirror image. While <FIG> shows the back-to-back plurality of lenses <NUM> running horizontally, the plurality of lenses <NUM> may also run vertically (as shown in lens sheet <NUM>) or even at an angle and still achieve a similar effect. In other embodiments, a lens sheet similar to lens sheet <NUM> containing the plurality of lenses <NUM> may be curved.

Claim 1:
A riot shield (2600a) comprising:
a clear body (2602a) having an outer surface and an inner surface;
a first lens sheet (2604a) having a first polarity disposed over the outer surface;
a second lens sheet (2612a) having a second polarity, spaced from the inner surface and the first lens sheet (2604a), the first polarity opposite the second polarity,
wherein upon a first projector (2606a) in communication with a first image source projecting an image onto the first lens sheet (2604a) through the second lens sheet (2612a), the image is visible on the first lens sheet (2604a) but not on the second lens sheet (2612a),
wherein the first lens sheet (2604a) having the first polarity comprises lenticular lenses disposed in parallel aligned to a first direction, and the second lens sheet (2612a) having the second polarity comprises lenticular lenses disposed in parallel aligned to a second direction, wherein the first and second directions are oriented at <NUM> degrees or at <NUM> degrees to one another.