LIGHT ENGINE FOR FRAME-SEQUENTIAL COLOR PROJECTION DISPLAY SYSTEM HAVING MONOCHROMATIC LIGHT SOURCES, SYSTEM AND DRIVING METHOD

摘要

A compact light engine (22) for a frame-sequential color projection display system employs sets of monochromatic light sources (26, 27, 28) such as LEDs. The LED sets are incorporated into compact light input modules (23, 24, 25) which include an array of reflectors (29, 30, 31) as light collectors, one for each LED, and a light coupling element (32, 33, 34) for coupling the collected light to a color combiner (35). The color combiner employs dichroic filters (36, 37) to combine the light of different colors into a beam. The beam's light intensity is homogenized by a homogenizing light guide (38). Increased light output is obtained without sacrificing lifetime by pulse-driving the LEDs at 5 or more times the rated max. DC driving current, at a 1/5 duty ratio.