一种离轴使用的同轴三反射系统的设计和装调

Design and adjustment of the coaxial three-mirror optical system used in field bias

本文设计了一种视场角为3°的离轴使用的同轴三反射系统,并从理论上分析了焦平面如何离焦补偿像差、反射镜倾斜和偏心之间的补偿关系。通过采取离焦、折镜的平动或转动、反射镜本身的偏心和倾斜相互补偿的方法,来补偿反射镜的装调误差。事实证明,比普通离轴三反射系统的装调容易实现,精确度高。

A coaxial three-mirror system used in field bias is designed. The system has the full field of view 3°, The possibility of compensating aberration with defocus is researched in theory. It is shown that the movement of the folding mirror has the same effect of defocusing, which is able to correct the aberration caused by the shift along the optical axis of the three mirrors when the focal plane is not able to move, The aberration caused by tilt and decentration of mirrors was also deduced theoretically with demonstration of offset relations. While the decentration or tilt of mirrors cannot be corrected by the movement of the folding mirror, aberration caused by the two error positioning can be compensated by each other making use of the offset relations said above. However, there are some differences in compensation relations among the three mirrors. All the methods to correct aberration are simulated with Zemax. The simulation results indicate that the system is much easier in the adjustment than off-axis three-mirror system.