Abstract: A class of novel structures which make novel use of polymer based reflective polarizing films in an improved polarization conversion system which are useful in liquid crystal projection systems that are easily manufactured, of lower cost, and permit the versatility of higher numerical aperture polarization conversions. Another aspect of the present invention are polarization modulating liquid crystal projection display systems utilizing the polarization conversion systems of the present invention.

Abstract: The fabrication of transmissive attenuating types of phase shift masks by formation of and selective etch of a layer, deposited on a substrate. This single layer provides both the phase shift and the attenuation required and is readily patterned and processed to produce attenuating phase shift masks.

Abstract: An apparatus for polarization conversion having a light source for supplying vertically and horizontally linearly polarized light to an optical path and a parabolic mirror disposed in the optical path and proximate to the light source. In different embodiments, the parabolic mirror has a mirror coating to induce a phase shift of 0°, 90°, or an arbitrary phase shift between incident light and reflected light. A polarizer means, preferably a reflective polarizer film, is disposed in the optical path for reflecting light of one of the linear polarizations and for transmitting the other linear polarization. Lastly, one or more waveplates are disposed in the optical path between the polarizer means and the parabolic mirror. The waveplates have opposing segments each having axes which are antiparallel to each other for recycling the reflected linear polarization by converting it to the transmitted polarization.

Abstract: An illumination apparatus including: at least two light sources, in which each of the light sources produce independent light beams; a controller for sequentially driving each of the light sources at a high power above their respective maximum rated power, to produce a respective light beam for each light source, and for leaving the remaining light sources at a low power below their respective maximum rated power, such that the time-average of the high and low power levels are set to a predetermined value for each of the light sources; and a combiner and director for sequentially combining each of the light beams from their respective light sources while being driven at high power into a common output beam with a fixed direction. Various combiner and directors are disclosed including tiltable mirrors under the control of the controller as well as optical systems.

Abstract: The fabrication of transmissive attenuating types of phase shift masks by formation of and selective etch of a layer, deposited on a substrate. This single layer provides both the phase shift and the attenuation required and is readily patterned and processed to produce attenuating phase shift masks.

Abstract: An illumination apparatus including: at least two light sources, in which each of the light sources produce independent light beams; a controller for sequentially driving each of the light sources at a high power above their respective maximum rated power, to produce a respective light beam for each light source, and for leaving the remaining light sources at a low power below their respective maximum rated power, such that the time-average of the high and low power levels are set to a predetermined value for each of the light sources; and a combiner and director for sequentially combining each of the light beams from their respective light sources while being driven at high power into a common output beam with a fixed direction. Various combiner and directors are disclosed including tiltable mirrors under the control of the controller as well as optical systems.

Abstract: An apparatus for polarization conversion having a light source for supplying vertically and horizontally linearly polarized light to an optical path and a parabolic mirror disposed in the optical path and proximate to the light source. In different embodiments, the parabolic mirror has a mirror coating to induce a phase shift of 0.degree., 90.degree., or an arbitrary phase shift between incident light and reflected light. A polarizer, preferably a reflective polarizer film, is disposed in the optical path for reflecting light of one of the linear polarizations and for transmitting the other linear polarization. Lastly, one or more waveplates are disposed in the optical path between the polarizer and the parabolic mirror. The waveplates have opposing segments each having axes which are antiparallel to each other for recycling the reflected linear polarization by converting it to the transmitted polarization.

Abstract: An optical projection display system, such as a liquid crystal display device, is disclosed. A feature of the present invention is that the projection display system utilizes a modified X-cube (or X-prism) arrangement wherein the internal angles of the prisms forming the modified X-cube deviate from 90.degree.. The utilization of the present modified X-cube arrangement improves contrast for checkerboard images, minimizes the possibility of spurious unwanted reflections from entering the projection lens as well as substantially eliminating glare and ghost images typically present using prior art X-cubes.

Abstract: A head mounted display for entering an image into the eye of a viewer along a viewing axis. The head mounted display has a light source for supplying unpolarized light to an optical path. Also provided is a first polarizer disposed in the optical path for rotating the unpolarized light to that of a first polarization. A second polarizer is also disposed in the optical path for blocking light of the first polarization from reaching the eye. A reflective light valve is disposed in the optical path for rotating the light of the first polarization to an image of a second polarization. Also provided is a concave mirror disposed in the optical path for focusing and reflecting the image of the second polarization. Lastly, a directing means is provided for directing the light of the first polarization to the reflective light valve, for directing the image of the second polarization to the concave mirror, and for directing the focused and reflected image from the concave mirror towards the second polarizer.

Abstract: The fabrication of transmissive attenuating types of phase shift masks by formation of and selective etch of a layer, deposited on a substrate. This single layer provides both the phase shift and the attenuation required and is readily patterned and processed to produce attenuating phase shift masks. Materials suitable for the phase shift layer include, but are not limited to, a layer comprising silicon, nitrogen and carbon; and, a layer comprising silicon, oxygen and molybdenum.

Abstract: An optical system is described consisting of reflection birefringent light valves, polarizing beam splitter, color image combining prisms, illumination system, projection lens, filters for color and contrast control, and screen placed in a configuration offering advantages for a high resolution color display. The system includes a quarter wave plate positioned to suppress stray reflection from the projection lens. The system also includes a second quarter wave plate disposed on the screen and a polarizing film disposed on the second quarter wave plate to suppress ambient light from illuminating the screen and entering the system.

Abstract: An optical system is described consisting of reflection birefringent light valves, polarizing beam splitter, color image combining prisms, illumination system, projection lens, filters for color and contrast control, and screen placed in a configuration offering advantages for a high resolution color display. In particular, the present invention includes a color splitting prism assembly having a plurality of output faces through which a separate color component is directed to be reflected by a respective light valve. Color absorbing filters are disposed at each of the output faces to absorb the color components not corresponding to the color directed through each output face.

Abstract: An optical system is described consisting of reflection birefringent light valves, polarizing beam splitter, color image combining prisms, illumination system, projection lens, filters for color and contrast control, and screen placed in a configuration offering advantages for a high resolution color display. The illumination system includes a light tunnel having a cross-sectional shape corresponding to the geometrical shape of the spacial light modulator to optimize the amount of light projected onto the screen.

Abstract: Optical arrangements for a high definition projection display using reflective light valves. Separate polarizing means are placed in proximity to respective separate reflective light valves tuned to the color to be modulated. A combining prism assembly combines the light reflected from each valve and directs the light onto a projection display.