Patent ID: 8947775
Filing Date: 2015-02-03
Classification: G02B

Abstract:
1. A catadioptric optical system comprising, in order from an object side along an optical axis: a first catadioptric unit; a second catadioptric unit disposed so as to have a space from the first catadioptric unit; and a lens group, wherein the first catadioptric unit includes a first object-side surface having a concave specularly reflective portion, and a first image-side surface having a first transmissive portion and a total internal reflection portion surrounding the first transmissive portion, wherein the second catadioptric unit includes a second object-side surface having a convex specularly reflective portion and a second image-side surface having a concave specularly reflective portion, and wherein light rays from an object are sequentially reflected by the first image-side surface, the first object-side surface, the second image-side surface, and the second object-side surface.