A projection optical system has three LCLVs; a first color-separating mirror for separating a substantially polarized light into a first and second color lights and a third color light; a half-wave plate for rotating the polarization direction of either one(s) of the separated light; a second color-separating...http://www.google.com.au/patents/US20030151725?utm_source=gb-gplus-sharePatent US20030151725 - Projection optical system and projector using the same
