US Patent 7717573 Projection display apparatus

A projection display apparatus has a light source, an image forming device for modulating light emitted from the light source with an image signal supplied thereto, and a reflective optical system for magnifying and projecting an image generated by the image forming device. The reflective optical system has a first reflecting mirror for reflecting light emitted from the image forming device and initially applied thereto, and a plurality of reflecting mirrors for successively reflecting the light reflected by the first reflecting mirror. The first reflecting mirror has a spherical reflecting surface, and a normal line passing through the crest of the spherical reflecting surface and a normal line passing through the image forming device extend nonparallel to each other.