Projection optical system for use in precise copy
AssigneeMatsushita Electric Industrial Co., Ltd.
InventorsTakeo Sato, Nobuhiro Araki, Koichi Kawata, Noboru Nomura, Atushi Ueno, Shotaro Yoshida
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Abstract
A projection optical system for use in a precise copy which uses a pair of catadioptric optical systems consisting of convex mirrors, concave mirrors, and phase correction members is shown. Two catadioptric optical systems commonly use an entrance pupil on a coaxis and are coupled so as to respectively face the phase correction members. Each of the concave mirrors has an opening at the center. Each of the convex mirrors has no opening in one embodiment but has an opening portion at the center in another embodiment.
Claims4
A projection optical system for use in making a precise copy, comprising:
- a pair of catadioptric optical systems each including an associated phase correction member, a convex mirror member having an opening at the center, and a concave mirror member having an opening at the center thereof, said convex mirror member and said concave member being arranged on a coaxis with a center of an entrance pupil,
- said pair of catadioptric optical systems being arranged rotationally symmetric around a reference axis as a center and being coupled coaxially by the associated phase correction member of each, one of said pair of catadioptric optical systems being arranged on a side of an object to be projected, and the other catadioptric optical system being arranged on aside of a projection image,
- said object being placed on a focal plane which is formed by one of said pair of catadioptric optical systems and on which said object is to be projected;
- and
- a coherent illuminating light source for convergently illuminating the object to be projected such that the illumination rays from said light source are focused by said one catadioptric optical system to the center of a plane of the entrance pupil.
Dependencies are inferred from the claim text.