Patent ID: 7940466
Filing Date: 2011-05-10
Classification: G02B,G03B

Abstract:
1. A viewing optical system positioned between a viewing plane as a virtual surface and an eye point, characterized by comprising, in order from said viewing plane side, a cemented lens in which at least one negative lens and at least one positive lens are cemented together, and one positive lens, with satisfaction of the following condition (1): where r3 is a radius of curvature of a lens surface positioned in said cemented lens and nearest to said viewing plane side, and f is a focal length of the whole viewing optical system; wherein the viewing optical system satisfies the following condition (2): where ε h is an exit angle (°) of a farthest off-axis chief ray on said viewing plane provided that said farthest off-axis chief ray is the outermost of off-axis chief rays that intersect an optical axis of said viewing optical system at a given position that is 20 mm spaced away from a lens surface located in said viewing optical system and nearest to said eye point side toward the eye point side.