Patent ID: 6220712
Filing Date: 2001-04-24
Classification: G02B,G03B

Abstract:
An oblique projection optical system for projecting a primary image on a primary image surface as a secondary image onto a secondary image surface in an oblique direction, the oblique projection optical system comprising a plurality of lens elements to effect an enlargement of the primary image, the oblique projection optical system including at least two eccentric lens elements,wherein an intermediate real image is not formed between the primary image and the secondary image,wherein the following conditions are satisfied, whereas image center rays are defined by light rays that operatively extend between a center of the primary image surface and a center of the secondary image surface:15.degree.<.theta..sub.oi <40.degree.20.degree.<.theta..sub.o <50.degree.0.degree..ltoreq..theta..sub.i <5.degree.where,.theta..sub.oi represents an angle formed between the primary image surface and the secondary image surface,.theta..sub.o represents an angle formed between a line normal to the secondary image surface and the image center rays, and.theta..sub.i represents an angle formed between a line normal to the primary image surface and the image center rays.