Abstract: A xenon arc lamp (10, 12) used as a high intensity light source for a liquid crystal light valve projector includes a cold mirror (16) that reflects visible reading light (18a, 18b) to the liquid crystal light valve and transmits infrared light to a heat transfer unit (20) that is arranged to remove heat from the projector. The heat transfer unit (20), positioned adjacent the back of the cold mirror, is formed by a group of wire grids (50,52,54,56) that are mutually parallel and spaced close to one another with the openings of the grids displaced so as to be out of alignment with one another from grid to grid. The grids are mounted in a housing (28,30,34) which includes a heat reflective backup plate (62) on the far side of the grids and a cooling gas is caused to flow through the housing and over the grids to remove the heat transferred to the grid from the infrared radiation.

Abstract: Creation of DC fields in a liquid crystal light valve caused a DC induced transient optical phenomenon in which output brightness level undergoes a change as the DC fields are redistributed within the liquid crystal light valve. Adverse effects of the DC induced transient optical output are minimized by employing a liquid crystal material of greatly decreased resistivity, which reduces the time constant of the liquid crystal device, making it comparable to the response time of the liquid crystal material itself.

Abstract: A reflective liquid crystal light valve projection system employs a polarizing beam splitter (16) to reflect light from a high intensity arc lamp (10) to a liquid crystal light valve (34) that is controlled by an image generator (36). Light reflected from the liquid crystal light valve is transmitted through the polarizing beam splitter (16) to a projection lens (38) and projected on a screen. Ghost images of the arc lamp source and diminished contrast are caused by light reflected from surfaces of the lens elements back to the liquid crystal light valve and then retroreflected back through the lens. The ghost images and diminished contrast are eliminated by interposing a broad band quarter wave plate between the lens and the polarizing beam splitter.

Abstract: A photosensitive layer of a liquid crystal light valve is made of a single crystal silicon wafer (14,70) bearingan irregular pattern of diodes (50a,50b, 60a,60b). The diodes are varied in size, shape and location so as to improve resolution, reduce interaction between the diode spatial pattern and the spatial pattern of input data, and, in one embodiment, to eliminate a difficult masking step. A masking step is eliminated by co-depositing a metal vapor and a silicon dioxide vapor to form random islands of cermets (50a,50b), each comprising an island of metal surrounded by a body of silicon dioxide. In other embodiments a pseudo-random mask is employed having an irregular pattern of holes (76) of varied sizes and locations.