自由曲面在离轴两反无焦系统优化设计中的应用  

Application of free-form surface in optimization design of off-axis two-mirror afocal system

作　　者：陈乾升 张蓉竹[1] CHEN Qiansheng;ZHANG Rongzhu(College of Electronics and Information Engineering,Sichuan University,Chengdu 610065,China)

机构地区：[1]四川大学电子信息学院,成都610065

出　　处：《光学技术》2024年第5期537-543,共7页Optical Technique

基　　金：中国工程物理研究院院长基金资助(YZJJZQ2022001)。

摘　　要：为了克服传统非球面在光学系统的结构设计中无法同时兼顾成像质量与系统体积要求的困难,使用自由曲面对一个离轴两反无焦系统进行优化。基于矢量像差理论,推导了当自由曲面在孔径光阑位置以及偏离孔径光阑两个不同位置时,系统的像差分布公式,并在此基础上有选择性引入Zernike项以平衡像差,具体讨论了不同类型像差的平衡参数选择。利用这一方法完成了一个小型化红外离轴两反无焦系统的设计,得到了一个入瞳直径为200mm,波段为2.4~3.0μm,放大倍率为5×,全视场角为0.4°,波前RMS最大值为0.0682λ(λ=2.7μm),平均值为0.0291λ的优化结果。与传统二次曲面设计方案进行比较,波像差有了明显改善,且MTF在中低频有显著提升,全视场内接近衍射极限。In order to overcome the difficulty of traditional aspherical surfaces in the structural design of optical systems that cannot simultaneously meet the requirements of imaging quality and system volume, a free-form surface is used to optimize an off-axis two-mirror afocal system. Based on the vector aberration theory, the aberration distribution formula of the system is derived when the free-form surface is at two different positions of the aperture diaphragm and deviates from the aperture diaphragm. Based on this, the Zernike items are selectively introduced to balance the aberration, and the selection of balance parameters for different types of aberrations is discussed in detail. Using this method, a miniaturized infrared off-axis two-mirror afocal system was designed, obtain an optimization result with an entrance pupil diameter of 200mm, a wavelength range of 2.4μm to 3.0μm, the magnification rate of 5, the FOV of 0.4°, and the maximum wavefront RMS is 0.0682λ(λ=2.7μm), the average value is 0.0291λ. Compared with traditional quadratic surface design scheme, the wave aberration has been significantly improved, and MTF has been significantly improved in mid to low frequencies, approaching the diffraction limit in the full field of view.

关 键 词：自由曲面 离轴两反无焦系统 ZERNIKE多项式 矢量像差理论 

分 类 号：O435[机械工程—光学工程]