Optical system and characteristics of an LCD projector with interleaved pixels using four LCD projectors

This paper describes an LCD projector that produces bright, high-resolution, large-screen images. The projector produces a composite overlaid image on screen by pixel interleaving, in which pixels of multiple LCD panels are shifted half a pixel with respect to each other. Greatly enhanced luminance and a very compact optical system is achieved by deploying multiple LCD projectors on opposite sides of a roof-shaped mirror with a vertical angle of 90°. As an alternative to the conventional large and ungainly optical stage for positioning on-screen images, a new positioning adjustment mechanism is proposed. This mechanism consists of two adjustable liquid prisms separated by air. Placed in the light path between the projection lens and the LCD panel, this mechanism allows four-axis shift and tilt adjustment and remote positioning control that can precisely adjust images to within several microns. A prototype projector incorporating four 640×480 pixel LCD panels has achieved a horizontal resolution of 700 TV lines, which is comparable to HDTV