Patent ID: 7172295

Claim:
A projection apparatus, comprising: a plurality of light emitting devices; a light valve comprising a plurality of valvelets optically coupled to the plurality of light emitting devices, each valvelet being controllable to direct light emitted by the light emitting devices and incident on the valvelet to either a projection path or a dump path; one or more photo detectors located on the dump path to measure at least one characteristic of the light emitted by least one of the light emitting devices, and directed onto the dump path, the one or more photo detectors outputting at least one electrical signal indicative of the at least one characteristic measured; a controller coupled to the plurality of light emitting devices and the one or more photo detectors to control an output characteristic of the light emitted by the at least one light emitting device based at least in part upon the at least one characteristic measured indicated by the at least one electrical signal; and wherein the plurality of light emitting devices comprise three light emitting devices, and the one or more photo detectors comprise three photo detectors.