Catadioptric optical system and image-pickup apparatus having the same

摘要

A catadioptric optical system of the present invention includes a catadioptric unit configured to condense light fluxes from an object and to form an intermediate image of the object, a field lens disposed at a position where the intermediate image are formed, and a dioptric unit configured to form the intermediate image on an image surface, and when νcat denotes a smallest Abbe number in Abbe numbers of materials of the first and second optical elements configuring the catadioptric unit and νdio denotes a smallest Abbe number in Abbe numbers of materials of a plurality of dioptric optical elements configuring the dioptric unit, νdio<νcat is satisfied.

主权项

1. A catadioptric optical system comprising:
a catadioptric unit configured to form an intermediate image of an object; a field lens disposed at a position where the intermediate image is formed; and a dioptric unit configured to form an image of the intermediate image, the dioptric unit including a plurality of dioptric optical elements, wherein the catadioptric unit includes: a first optical element including a first light transmission part having a convex surface on an object side, a positive refractive power near an optical axis, and a first backside reflector having a first reflective film on a surface on the object side in a periphery; and a second optical element including a second light transmission part having a concave surface on the object side, a meniscus shape, a negative refractive power near the optical axis, and a second backside reflector having a second reflective film on a surface on an image side, wherein the light flux from the object passes through the first light transmission part, the second backside reflector, the first backside reflector, and the second light transmission part in this order, and is emitted to a field lens side, and wherein the following condition is satisfied:
vdio