A light source optical system for projection 1, dichroic mirrors 21, 22 disposed to have a predetermined included angle .beta., a reflection type liquid crystal optical element blocks 31-33 each including a closely contacted converging lens and having a reflection surface and a projection optical system...http://www.google.fr/patents/US5648860?utm_source=gb-gplus-shareBrevet US5648860 - Projection type color liquid crystal optical apparatus
Projection type color liquid crystal optical apparatus
