Abstract: A projection subsystem includes a light engine that provides a collection lens, a collimator and at least one solid state light emitter. A projection lens assembly receives the image and provides a projection beam having a luminous flux level. The projection subsystem has a portability efficacy.

Abstract: A liquid crystal display (LCD) projection system including a projection panel, a light source, and a reflector. The projection panel includes an LCD and a polarizer on one side of the LCD and a reflective polarizer on the other side. The reflective polarizer is a multilayer stack of pairs of adjacent material layers. Each of the layer pairs exhibits a refractive index difference between the adjacent layers in a first direction in the plane of the reflective polarizer and exhibits essentially no refractive index difference between adjacent layers in a second direction in the plane of the reflective polarizer and orthogonal to the first direction. A quarter-wave plate is secured to the reflective polarizer. Light rays from the light source either pass through the reflective polarizer, and on to the LCD, or are reflected back toward the light source, depending on their polarization. Light which is reflected by the reflective polarizer is reflected by the reflector back toward the LCD again.

Abstract: A liquid crystal display projection system for providing improved brightness. A light beam is split by a polarizing beam splitter into two polarized beams having substantially orthogonal polarizations. The beams are reflected by one pair of mirrors toward an opposite side of a liquid crystal display, so that the two beams pass through the display in opposite directions. The two beams are then reflected by another pair of mirrors toward another polarizing beam splitter, where the beams are recombined into a single beam for projection onto a screen.

Abstract: A liquid crystal projection panel for use in a projection system. The projection panel is comprised of a large number of pixels of liquid crystal defining a image forming plane provided between two transparent substrates. Microlens arrays are provided on both sides of the projection panel. The microlenses in both arrays have focal lengths such that parallel light rays entering the microlenses at an angle perpendicular to the arrays are focused at points beyond the image forming plane of the display.

Abstract: A reflective liquid crystal display overhead projection system. The projection system includes a reflective polarizer, a phase modulating liquid crystal display on the reflective polarizer, and a fresnel lens on the liquid crystal display. Unpolarized light rays are directed toward the fresnel lens, pass through the liquid crystal display, and are reflected and polarized by the reflective polarizer. The light rays then pass back through the liquid crystal display and the fresnel lens and on toward a projector head, where the light rays are analyzed by a polarizer and projected toward a screen.

Abstract: A liquid crystal display (LCD) panel employs a cholesteric polarizer which passes light of a first circular polarization, but reflects light of a second circular polarization. The LCD panel may be monochrome or color; in the color embodiments, several different color filters are used, each having one or more cholesteric polarizers tuned to a specific bandwidth in the visible spectrum. These polarizers replace dyed (neutral or dichroic) polarizers of prior art LCD panels, and provide improved color purity. The invention may be enhanced by providing a light recycling scheme whereby the handedness of the circularly polarized light reflected by the polarizers is changed and redirected back to the polarizers. This recycling scheme may also be adapted to provide an overhead projector having a high output polarized light source, particularly useful in conjunction with an LCD panel.

Abstract: An article having improved electrostatic charge transfer properties. The improvement in charge transfer properties results from subjecting a layer of photoconductive-insulative material or dielectric material on the charge donor or a layer of dielectric material on the charge receptor, or both layers, to plasma treatment process to provide an oxygen-enriched surface to the photoconductive-insulative layer and/or the dielectric layer.