Projection optical system and a projection type image display apparatus

摘要

There is disclosed a projection optical system which is capable of moving a projected image within a predetermined region (effective projection region). The projection optical system, which projects an image of an object surface in the effective projection region of a predetermined image surface comprises two or more optical systems, among which a first optical system on the object surface side comprises a zoom portion which zooms the projected image. The projection optical system further comprises one or more rotatable members which rotate around the position of an exit pupil of the first optical system or its vicinity. In addition, by rotating the one or more rotatable members, the projected image is moved within the effective projection region.