Optical system for three-panel LCD projector - has prim. colour display panels all equidistant from white-light source in system of colour sepn. and recombination

摘要

Light from a metal halide lamp (111) is divided into its three prim. colours (R,G,B) by a system of filters (113,121) and mirrors (112,122-125). A condenser unit comprises three collector lenses (131-133) with LCD panels (141-143) in the respective colour path, which are recombined by two dichroic mirrors (151,152) ahead of the projection lens (160). The blue filter (121), red mirror (122) and panchromatic mirrors (123-125) are arranged so that the three optical paths from the source to the LCD panels are all equal in length. ADVANTAGE - Projection is improved with shorter distance between focus and rear of projection lens, and fewer dichroic mirrors in colour synthesiser.