Importance

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Abstract

A multimedia projector (110) employing a color wheel (120) uses a light guide (152) to transmit light from the color wheel to a photo detector (156) that detects a particular color or colors of light to provide a index mark signal to a display controller (56) to synchronize red, green, and blue image data with the associated color wheel filter segments. An integrator tunnel (122) adjacent to the light guide provides uniform, high intensity light from the color wheel to a display device, such as a DMD (130). The photo detector senses otherwise wasted light rays as sensing rays (150) that are reflected by a light source reflector (114) and propagated through the color wheel. To collect some of the sensing rays, the light guide is preferably bonded to the integrator tunnel. The light guide has a slanted output end (154) that reflects the collected sensing rays toward a photo detector on a circuit board (148). Because the light guide is bonded to the integrator tunnel, and because the color wheel rotates its filter segments from the light guide toward the integrator tunnel, the photo detector senses color changes slightly before they are received by the DMD, which is advantageous because the resulting predictive timing is consistent from one projector to the next, thereby eliminating timing adjustments.

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First Claim