Patent ID: 8217374

Claim:
A projection-type image display apparatus comprising: a light source; a modulator for modulating and outputting light radiated from the light source based on a video signal; and a projection optical system for enlarged projection from a primary image surface toward the modulator to a secondary image surface toward a screen, wherein the projection optical system comprises: a first optical system that forms an intermediate image of the primary image surface; and a second optical system having a concave reflector that forms the secondary image surface according to the intermediate image, wherein the concave reflector is unique to the second optical system and has an unused part removed when placed to the side of the secondary image surface, and wherein as a light beam travels from the center of the primary image surface to the center of the secondary image surface it crosses an optical axis of the first optical system, reflects on the concave reflector, crosses the optical axis again, and reaches the secondary image surface.