Patent ID: 7170678

Claim:
An optical color separation and synthesis system comprising: at least first to fourth polarization beam splitters which chromatically separate white light into a plurality of color beams and which guide the plurality of color beams into a plurality of reflective type spatial light modulation elements corresponding to colors and which chromatically synthesize the respective color beams optically modulated by the respective color reflective type spatial light modulation elements according to a video signal to thereby emit color synthesized light, wherein the first polarization beam splitter is disposed on an incidence side of the white light and the fourth polarization beam splitter is disposed on an emission side of the color synthesized light; at least one optical function plate arranged facing any of the first to fourth polarization beam splitters; a base platform on which the first to fourth polarization beam splitters are arranged in such a manner that polarization separating surfaces of the polarization beam splitters form an X-shape and onto which the polarization beam splitters are bonded while a predetermined gap is formed between facing surfaces of the polarization beam splitters; and first and second frames each of which has an opening in a middle portion thereof and a stepped portion for bonding one of said optical function plates on a peripheral portion thereof, the first frame being secured to the first polarization beam splitter, and the second frame being secured to the fourth polarization beam splitter, wherein the first frame comprises a bonding flange portion which is to be bonded to the first polarization beam splitter and which is formed along any side surface of the first frame so as to protrude behind a rear surface of the first frame on the opposite side of a front surface of the first frame, and wherein the second frame comprises a bonding flange portion which is to be bonded to the fourth polarization beam splitter and which is formed along any side surface of the second frame so as to protrude behind a rear surface of the second frame on the opposite side of a front surface of the second frame.