Delta America Ltd.

Amjad I Malik

Kenneth E Salsman

Gary B Kingsley

A projection illumination system which includes a source light with a projection axis passing generally centrally through this light, and dual-side light-gathering structure, including a reflector and a TIR lens structure generally embracing the source light on opposite sides thereof and along the projection axis, with this light-gathering structure being capable of directing, ultimately outwardly from the source light and unidirectionally along the projection axis, a major percentage of light generated by the source light.

Projection illumination system for tricolor projectors

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 and the exterior square contains plural turning mirror elements. 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. Preferably, coated plate glass dichroic elements within the invented image provide dual functionality with respect to various of the three colored light beams, i.e. splitting two unmodulated color beams incident upon a first surface thereof and reflecting one of them while simultaneously combining the reflected one of them with a modulated third color beam incident upon an opposite surface thereof to produce a light beam that emerges from the first surface that contains both modulated and unmodulated color components. Pupil and image astigmatism correction are performed by plate assemblies positioned in the input white and output tricolor paths of the engine.

Optical engine for tricolor projectors

The invented optical engines are characterized as including generally parallel planar glass plate-mounted or coated dichroic and turning mirror and light valve elements. An important topological feature of the invented optical engines is the fact that like optical elements are positioned and oriented to be coplanar, i.e. the light-splitting dichroic mirror elements are coplanar with one another, the split beam-turning mirror elements are coplanar and the light valves are coplanar. This important feature of the invention renders compact optical engines that are simply and inexpensively manufactured and maintained because the critical optical elements are in part self-aligning when like optical elements are placed in an aligning mounting structure or more preferably on a common substrate that renders them self-positioning and self-aligning relative to one another. A common white light entry region and modulated tricolor beam exit region of the invented optical engines, coupled with equal optical path lengths through the engine, permit the use of a single input pupil astigmatism correction plate near the entry region and a single output image astigmatism correction plate assembly near the exit region of the engines. The optical engines may be used along with conventional other optical elements including, for example, a white light source and an optical output stack, to render a pixel-modulated tricolor projector.

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Vancouver, WA, United States of America

Amjad I Malik