提高离轴三反射镜系统成像质量的途径

介绍了离轴三反射镜系统的设计方法 ,即在共轴三反射镜系统求得初始结构参数的基础上 ,将光阑置于第一面 ,适当离轴 ,在避免中心遮拦后再对系统进行优化。利用具有高次非球面项的镜面 ,并对镜面实施离轴、倾斜 ,这都能有效地提高离轴三反镜系统的成像质量。例举了一个大相对孔径、大视场角和一个相对孔径不大、视场角较小的离轴三反射镜系统作为设计的实例。通过对镜面加高次非球面系数、离轴量、倾斜量并进行优化 ,得到了成像质量良好 ,系统的总长度较小的结构

Approach to increase the image performance of the uncoaxial three-mirror reflective system

The method on how to design the uncoaxial three reflective system is introduced.It is based on the design of the coaxial three reflective system. By designing the coaxial three reflective system, the original structure parameters of the uncoaxial three reflective system are obtained. The aperture is placed on the first surface and decentered to a suitable position to avoid the obstruction of the light. The system is optimized. It is pointed out that the use of uncoaxial,tilted , polynomial aspheric reflective surfaces can improve the image quality effectively. Two examples are given, one is F =10 and small field angle, another is F =1.67 and wide field angle. The evaluation shows that the optimization of the decenter amount, tilt degree, aspheric coefficients can not only increase the image quality, sometimes also help to shorten the whole length of the system.