反射光学系统杂散光的消除

成像光学系统中的杂散光会引起像质模糊和对比度下降，在对像质要求较高，或被探测的光能量微弱的情况下，必须对杂散光进行消除。R-C (Ritchey-Chretien)系统是卡塞格林系统的一种形式，在地面光电探测和空间对地观测等方面都有广泛应用。以焦距为2 m，相对孔径为1/4的R-C系统为例，介绍了利用计算机仿真技术进行消杂散光设计和评价的原理，结合CAD建模进行了主镜内遮光罩、外遮光筒、次镜百叶窗式遮光罩的设计。使用光线模拟追迹软件TRACEPRO建立的测试系统进行仿真测试，得到R-C系统的杂光系数为6.4%，证明了设计的可行性，为应用和进一步的优化设计提供了依据。

Stray light removing of reflective optical system

The stray light in optical imaging system could blur the image and decrease the contrast. It is necessary to eliminate the stray light when the system requires a high image quality and the detected light is weak. As a form of Cassagrain system, R-C (Ritchey-Chretien) system is widely used in the field of imaging system on the ground and space-based remote sensing. A R-C system with foci of 2 m and f-number F/4 was taken for an example, the principles of stray light eliminating and evalutiong in reflective optical system was put forward. Lens hood in the main mirror, lens hood outside and window shade, lens hood in the secondly mirror were designed by CAD modeling. The design result was tested by light tracing in simulating software TRACEPRO, which showed the stray light ratio of the R-C system is 6.4%. This proved the feasibility of the stray light eliminating design. According to the analysis, the further optimization can be carried out.