| 摘要 |
PROBLEM TO BE SOLVED: To obtain a catadioptric system having a large angle of view and a high f-number, restraining aberration to be small and having a compact constitution. SOLUTION: The catadioptric system is constituted by arranging a 1st lens L1 which receives incident luminous flux from an object side and has positive refractive power, a main mirror M1 whose peripheral part is set as a reflection surface, which is constituted by providing a light transmission aperture part AP2 at the center part and which refracts and reflects the light transmitted through the 1st lens L1 to the object side, a sub mirror M2 which refracts and reflects the light reflected from the mirror M1 to an image surface side, a 2nd lens L2 which is arranged near the aperture part AP2 of the mirror M1, receives the light reflected by the mirror M2 and has negative refractive power, and a 3rd lens group L3 which is arranged on the image surface side from the 2nd lens L2 on an optical axis OA extended from the object side to the image surface side. The lens surface on the object side of the 1st lens L1 is formed to be aspherical. COPYRIGHT: (C)2004,JPO
|
