Athermal catadioptric homocentric optical system

Abstract

The invention discloses an athermal catadioptric homocentric optical system. The system comprises: a fairing, a scanning mirror, a primary mirror, a secondary mirror and a collimating lens group. The primary mirror and the fairing possess a common spherical center and a diaphragm is located on the common spherical center. The primary mirror and the secondary mirror use a same substrate material. The collimating lens group comprises: a first lens, a second lens and a third lens. And performance parameters of the three lenses satisfy following three equations. By using the system of the invention, athermalization can be realized in a scope of (minus 30 degree, 60 degree). Spherical aberration of a hood can be corrected and simultaneously, an optical path does not generate coma aberration, astigmatism and distortion. Heat defocusing amounts of the primary mirror and the secondary mirror are zero. The three lenses of different materials form the collimating lens group. Distribution of a focal power satisfies achromatism and athermalization conditions.

Description

technical field [0001] The invention relates to the field of airborne optoelectronics, in particular to an athermalized catadioptric concentric optical system. Background technique [0002] Infrared optical systems need to work under harsh environmental conditions, and changes in ambient temperature are one of the severe tests for infrared optical instruments. Due to the relatively large refractive index temperature coefficient dn / dt of infrared optical materials, such as the commonly used infrared optical single crystal germanium is 3.96×10 -6 / °C, which is nearly 200 times that of visible light glass, so the impact of ambient temperature on the infrared system is particularly serious. When the ambient temperature changes, the curvature, thickness and spacing of the optical components will change, and the refractive index of the component material will also change, which will cause the focal length of the system to change, and the image plane will shift, resulting in a sha...

AI Technical Summary

Problems solved by technology

At present, this method is mature and widely used in China, but the volume and complexity of this system are large, and the reliability is reduced.

(3) Mechanical passive athermalization technology uses a variety of materials with different expansion rates or memory alloys to achieve athermalization compensation, which has high reliability, but the disadvantage is that it is bulky and extremely cumbersome

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