Catadioptric long-focal-length large-view-field small-size imaging optical system

Abstract

The invention discloses a catadioptric long-focal-length large-view-field small-size imaging optical system. The catadioptric long-focal-length large-view-field small-size imaging optical system comprises a front group positive-focal-power reflection type optical group and a rear group negative-focal-power transmission type optical group. The front group positive-focal-power optical system comprises a concave primary mirror reflector and a convex secondary mirror reflector; and the rear group negative-focal-power transmission type optical group is composed of a positive lens group, a negativelens group and a small focal power meniscus lens. An object imaging light beam is reflected by the concave primary mirror reflector and the convex secondary mirror reflector in sequence, then enters atransmission-type system, is refracted by the positive lens group, the negative lens group and the small focal power meniscus lens in sequence, and then is imaged on an image plane. In the invention,requirements of a high resolution, a large breadth range and a small size and weight of a space camera are met.

Description

technical field [0001] The invention belongs to the technical field of optical imaging systems, in particular to a catadioptric-based long focal length large field of view small volume imaging optical system. Background technique [0002] With the increase of aerospace space exploration missions, the observation requirements and volume weight of aerospace cameras are also getting higher and higher. For example, the higher resolution of satellite imaging results in a focal length generally greater than 500mm, and the larger camera field of view needs to be 3°~ 6°, due to the increase in width requirements, the number of detectors has also changed from one piece to multi-piece splicing. At the same time, the requirements for camera weight and volume are becoming more and more stringent. [0003] The existing implementation methods mainly include the following: [0004] 1) A catadioptric system with no-refractive lens group is used, and a negative field lens is used to correc...

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Problems solved by technology

Using this method, since the positive and negative lens groups do not produce focal power, the correction of field curvature can only rely on the negative field lens in front of the focal point, resulting in a small field of view and a short back intercept. The use of products with large back focus for image plane optical stitching is limited

[0005] 2) The off-axis three-mirror system uses three off-axis mirrors to achieve a large field of view of the line array, and has the advantages of no chromatic aberration and a large back intercept, but this system can only achieve a larger field of view in the direction of the line array. The field of view in one direction is small, which is not suitable for area staring or video imaging, and the off-axis reflective system is larger and heavier than the coaxial reflective system

[0006] 3) Telephoto transmission system, this system adopts the telephoto structure with the positive lens behind the front and rear lens groups, which can achieve a larger field of view and a shorter system length than the focal length, but due to the limitation of the transmission structure, this system The length of the system will be much longer than that of a reflective system

And because the transmission system is not suitable for the system with a long focal length due to the limitation of the lens aperture

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