Patent ID: 10401596

Abstract:
A projection optical system capable of performing magnification projection of an image displayed on an image display surface, with a 40° half angle of view, or more includes, in an order from a magnification side: a first optical system; and a second optical system, wherein the second optical system forms an intermediate image of the image, the first optical system performs magnification projection of the intermediate image, and the following conditional expressions (1) and (2) are satisfied: 1<Ff/|Fw|<2 . . . (1), 0.4<Lf/Lw<0.6 . . . (2), where, Ff: a focal length of the first optical system, Fw: a focal length of an entire system, Lf: a distance on optical axis, from a most-magnification-side surface vertex to the intermediate image, in the first optical system, Lw: an entire length of a lens.