Abstract: A flat-panel projection display comprises a slab waveguide having a preferably embossed diffraction grating on one face, a lens for directing light into an edge of the waveguide, and in the focal plane of the lens a liquid-crystal modulator for modulating the intensity of the light as a function of lateral position and elevational direction of travel. The light is ejected from the slab waveguide by the grating at angles corresponding to the input angles, giving a virtual display. The light from the modulator can be expanded in one dimension by passing through a magnifying waveguide, followed by scattering in the plane by a screen and projection by a lens at the other end of the waveguide. Head-up and 3-D displays can be constructed using this principle.

Abstract: An achromatic flat-panel projection display comprises a video projector 2a, a condensing lens (26) and a tapered transparent slab spreading the image input from the projector over the area of th slab. To compensate for dispersion in the slab a dispersive prism is used at the input edge of the slab, whose dispersion cancels out the dispersion of the slab. The prism can be a separate part of simply a bevel in the input edge, i.e. the thick end of the slab.

Abstract: A flat-panel display comprises a projector (21-23) illuminated by a collimate light source such as an infra-red laser, a waveguide (1) which ejects rays at a distance along the axis of propagation related to their angle of injection into the edge of the waveguide, an input slab (3) for magnifying the projected image in the width dimension in the plane of the panel perpendicular to the axis of propagation, and a phosphor output screen which converts the infra-red light to the visible. The use of monochromatic light within the waveguide reduces dispersion problems, and the use of a triad of projectors, each injecting at a different angle, makes registration relatively simple.

Abstract: A flat-panel projection display comprises a transparent slab and integral area grating, a transparent rod with rectangular cross-section and integral linear grating, arranged along the edge of the slab, and a small video projector. The projector is arranged to direct a virtual image into the end of the rod, directly or via mirrors, the light travelling along the rod via total internal reflection. The linear grating diverts the light into the plane of the slab, and the area grating projects it out of the slab towards a viewer, so that the viewer sees an image at infinity.

Abstract: A flat-panel projection display comprises a slab waveguide having a preferably embossed diffraction grating on one face, a lens for directing light into an edge of the waveguide, and in the focal plane of the lens a liquid-crystal modulator for modulating the intensity of the light as a function of lateral position and elevational direction of travel. The light is ejected from the slab waveguide by the grating at angles corresponding to the input angles, giving a virtual display. The light from the modulator can be expanded in one dimension by passing through a magnifying waveguide, followed by scattering in the plane by a screen and projection by a lens at the other end of the waveguide. Head-up and 3-D displays can be constructed using this principle.

Abstract: A flat-panel projection display comprises a transparent slab and integral area grating, a transparent rod with rectangular cross-section and integral linear grating, arranged along the edge of the slab, and a small video projector. The projector is arranged to direct a virtual image into the end of the rod, directly or via mirrors, the light travelling along the rod via total internal reflection. The linear grating diverts the light into the plane of the slab, and the area grating projects it out of the slab towards a viewer, so that the viewer sees an image at infinity.

Abstract: A flat-panel projection display comprises a tapered transparent slab (1), a projector (2) adapted to inject images into the thick end of the slab, a translucent screen (3) over the face of the slab from which the display is to be viewed, and spacers holding the screen away from the slab so that light emerging from the face of the slab can spread to cover the area of the screen. In this way the gaps or blank strips that would otherwise be present at the points where the light bundles are being reflected off the rear surface of the tapered waveguide are eliminated.

Abstract: An achromatic flat-panel projection display comprises a video projector 2a, a condensing lens (26) and a tapered transparent slab spreading the image input from the projector over the area of the slab. To compensate for dispersion in the slab a dispersive prism is used at the input edge of the slab, whose dispersion cancels out the dispersion of the slab. The prism can be a separate part of simply a bevel in the input edge, i.e. the thick end of the slab.

Abstract: A wide-field-of-view projection display comprises a circularly symmetric lens and an array of light emitters, positioned along the focal circumference of the circularly symmetric lens so that light from each of the light emitters is substantially collimated by the lens in a different direction. A ray-diverting means, such as a slab waveguide or a reflector, ejects the collimated light out of the plane of the lens to the viewer. The planar circularly symmetric lens has no aberration, allowing adjacent views to be seamlessly joined because they can all be diffused by the same angular amount.

Abstract: A flat-panel camera comprises a tapered transparent slab 1, a prismatic sheet 3 for introducing light into one face of the slab at near the critical angle so that it is reflected along the slab towards the thick end, and a miniature camera 2 receiving light emerging from the thick end of the slab at an angle depending on where the light entered the slab. An image processor 7 eliminates distortion in the image such as gaps caused by the light missing the camera.

Abstract: A large-area collimated beam of radiation is formed by re-directing a beam of small projected area off one or two orthogonal surfaces which are faceted or have a non-specular reflection angle and which spatially distribute the incoming beam across their surface area. Preferably there are two expansion stages, one for each dimension. If the input beam is linearly polarised then the output beam will also be polarised. The polarisation will undergo a rotation through 90 degrees. The beam expander is compact and suitable for use in liquid-crystal flat-panel displays.

Abstract: A flat-panel display comprises a projector (21-23) illuminated by a collimate light source such as an infra-red laser, a waveguide (1) which ejects rays at a distance along the axis of propagation related to their angle of injection into the edge of the waveguide, an input slab (3) for magnifying the projected image in the width dimension in the plane of the panel perpendicular to the axis of propagation, and a phosphor output screen which converts the infra-red light to the visible. The use of monochromatic light within the waveguide reduces dispersion problems, and the use of a triad of projectors, each injecting at a different angle, makes registration relatively simple.

Abstract: An optical waveguide system includes a generally planar waveguide 1 arranged so that light can be injected by a projector 2 into one edge at a range of out-of-plane angles. The waveguide 1 is tapered so that different out-of-plane angles, after being totally internally reflected for a certain distance, leave the waveguide at different respective points along the waveguide. This expands the image in the direction of propagation along the waveguide. Meanwhile the image is expanded transversely by a parallel-sided input waveguide 3. A large-area flat-panel display is thus created, or the planar waveguide can be used as a planar collimating light source or, using layers of controllable optical index, an optical switch.

Abstract: An optical waveguide system includes a generally planar waveguide 1 arranged so that light can be injected by a projector 2 into one edge at a range of out-of-plane angles. The waveguide 1 is tapered so that different out-of-plane angles, after being totally internally reflected for a certain distance, leave the waveguide at different respective points along the waveguide. This expands the image in the direction of propagation along the waveguide. Meanwhile the image is expanded transversely by a parallel-sided input waveguide 3. A large-area flat-panel display is thus created, or the planar waveguide can be used as a planar collimating light source or, using layers of controllable optical index, an optical switch.

Abstract: A video display for two or three dimensions has a flat liquid-crystal screen 2 which ejects light from the plane at a selectable line 3. One or, in the case of a 3-D display, several video projectors 1 project a linear image into the plane from an edge. A complete image is written on the screen by addressing the line with appropriate images as it is scanned down the screen. To screen a three-dimensional image the video projectors, each projecting an image as seen at a slightly different angle, combine to constitute a three-dimensional display which produces a three-dimensional image that is one line high.

Abstract: A polychromatic three dimensional display comprises a first (5) and second (8) image sources, the second image source (8) adapted to reduce selectively the field of view of the first image source to provide thereby a time multiplexed three dimensional autostereoscopic image. The display also comprises a switching color filter (12) disposed adjacent to the second image source which comprises a plurality of regions each switchable between different colors to enable color modulation of the generated image.