Ronchi光栅检测非球面镜系统的设计及实验研究  

Design and experimental research of aspheric mirror system based on Ronchi grating testing

作　　者：包兴臻[1] 何锋赟[1] 赵楠[1] 董健[1] BAO Xingzhen;HE Fengyun;ZHAO Nan;DONG jian(Research and development centre,Changchun Institute of optics,Fine Mechanics and physics,Chinese Academy of Sciences.,Changchun 130000,China)

机构地区：[1]中国科学院长春光学精密机械与物理研究所精密仪器与装备研发中心,吉林长春130000

出　　处：《光学技术》2023年第1期57-63,共7页Optical Technique

基　　金：吉林省发改委项目(2020C030-4)。

摘　　要：为指导大口径非球面反射镜的精磨至抛光过程的加工,设计了Ronchi光栅检测系统。采用零位补偿器替代补偿光栅的设计制作,既能用Ronchi法对粗加工过程检测,也能用于干涉仪检测;模拟Ronchi检测过程中条纹形状与对应面型像差的关系,通过判断条纹形状对加工过程进行指导;针对某600mm口径的双曲面反射镜,设计了Ronchi光栅检测系统、零位补偿系统、成像系统。分析检测系统元件剩余反射对成像结果的影响,并提出相应的解决方案。分析表明,在Ronchi光栅检测光路中,分光棱镜表面5%剩余反射相对0.1%剩余反射,像面暗条纹的照度值增量大于30倍,条纹明暗对比度下降,难以分辨;光栅剩余反射大于3%时条纹中心产生亮斑,亮斑照度与条纹照度值比大于5倍。通过优化系统结构,降低元件表面剩余反射,提高了像面条纹对比度。将Ronchi检测系统用于双曲面镜抛光过程的检测,测得双曲面粗抛光后RMS值为0.042λ,PV值为0.291λ,可有效指导非球面的精磨与粗抛光过程。In order to guide the processing for grinding to polishing large aperture aspheric mirrors, Ronchi testing system is designed. Firstly, the null compensator is used to replace the compensation grating, which not only for detection of rough machining process by Ronchi test, but also for the testing of interferometer. Secondly, the relationship between the fringe shape and tested surface aberration in the Ronchi system is simulated, and polish process is guided by judging the fringe shape. Then, for a 600mm diameter hyperboloid mirror, Ronchi grating test system, null compensation system and imaging system are designed. The influence of residual reflection of components in test system is analyzed, and the resolution methods are proposed. The result shows that in the Ronchi test system, 5% residual reflection on the plitting prisms surface relative to 0.1%, the illumination of the dark stripes on the image plane increases more than 30 times, and the contrast of the brightness and shade stripes decreases, which is difficult for resolution. When the residual reflection of the grating is greater than 3%, there are bright spots in the center of the stripe, and illumination of the bright spots is 5 times more that of the stripe. By optimizing the structure of the system, the residual reflection on the surface of the component is reduced, and contrast of the image stripes are improved. Ronchi test system was used to detect the polishing process of hyperboloid mirror, and the RMS value after rough polishing of hyperboloid was measured to be 0.042λ, PV is 0.291λ. It can guide process of fine grinding and polishing of aspheric surfaces effectively.

关 键 词：Ronchi光栅检测 像差 剩余反射 条纹对比度 

分 类 号：O439[机械工程—光学工程]