Quasi coaxial small-distortion long-focus four-reflection optical system

Abstract

The invention provides a quasi coaxial small-distortion long-focus four-reflection optical system, belongs to the technical field of space optics, and aims at solving the problem of small field angle of the existing coaxial system. The optical system comprises an aperture stop, a primary reflector arranged at the back of the aperture stop, a secondary reflector arranged on a reflecting light path of the primary reflector, an elbow mirror arranged on the reflecting light path of the secondary reflector, a third reflector arranged on the reflecting light path of the elbow mirror, another elbow mirror arranged on the reflecting light path of the third reflector, a fourth reflector arranged on the reflecting light path of the elbow mirror, and an optical system focal plane; the optical system is of a quasi coaxial structure; the aperture stop is polarized; the primary reflector is of a structure of an aspheric partial light transmitting area that is downwards polarized and symmetric opposite to an optical shaft; the elbow mirror, the third reflector, the another mirror and the fourth reflector in the light path at the back of the secondary reflector are positioned at the back of the primary reflector; the secondary reflector, the elbow mirror, the third reflector, the another elbow mirror and the fourth reflector are light transmitting aperture areas by size.

Description

technical field [0001] The invention relates to a quasi-coaxial low-distortion long-focal-length four-reflection optical system, which belongs to the field of space optics technology. Background technique [0002] With the rapid development of CCD sensor devices and the continuous progress of optical processing, detection, and adjustment technologies, aerospace remote sensing imaging continues to develop in the direction of high resolution. The requirement for high resolution is also raised. Applying high-resolution cameras to aerospace three-dimensional mapping needs to solve a series of problems. The first problem that needs to be solved is a low-distortion, small-volume, long-focus optical system that meets the requirements of surveying and mapping accuracy. . [0003] At present, the most widely used three-reflection structure in aerospace remote sensing can correct system distortion well by using COOK-type off-axis structure. The Chinese patent publication number is C...

AI Technical Summary

Problems solved by technology

The Chinese patent publication number is CN102087408A, titled "a large field of view, ultra-low distortion, multi-spectral three-reflection optical system". Its distortion correction is good, but the large size of the off-axis system is the main factor that limits its long focal length application. In the mid-term of the above-mentioned invention, the volume can be controlled to 0.3 to 0.6 times the focal length of the system, but the volume of the optical system with a focal length of 12 meters or more is still very large

However, the main factor limiting the application of the coaxial system is that its field of view is small, such as the field of view in the above-mentioned invention is 1.5°, and due to the existence of occlusion, the modulation transfer function curve of the optical system will drop significantly in the middle frequency band

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