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.

Abstract: A receiver protection arrangement in which a voltage dependent on aerial voltage and a voltage dependent on aerial current are aggregated and applied to means responsive to a predetermined aggregate level to effectively short circuit the aerial lead. Additional means may be provided to dissipate energy in the input stage of a protected receiver to cause a reduced impedance to be reflected across the output of the protective arrangement.