IMPROVED OPTICAL ENGINE FOR TRICOLOR PROJECTORS

摘要

Described is an improved optical engine including dichroic mirror elements that have opposing substantially parallel planar surfaces, with the mirror elements positioned and oriented selectively and simultaneously to split a first light beam incident upon one of the opposing surfaces and to recombine modulated second and third beams incident upon the other of the opposing surfaces, wherein a beam of light emerging from the one of the opposing surfaces contains both modulated and unmodulated color components. Preferably, the invented optical engine takes the form of concentric squares, when viewed normal to a plane in which its optical elements lie, wherein the interior square contains plural dichroic elements (items 12, 22, 34, and 38) and the exterior square contains plural turning mirror elements (items 14, 16, 24, and 32). The optical engine may be used along with conventional other optical elements including, for example, white light sources, turning mirrors, liquid crystal shutters and optical output stacks, to render a pixel-modulated tricolor projector.