高精度离轴凸非球面反射镜的加工及检测

为了提高离轴凸非球面反射镜的面形精度和光轴精度,研究了离轴凸非球面反射镜的加工与检测技术。首先,描述了离轴三反消像散(TMA)光学系统以及作为该光学系统次镜的离轴凸非球面反射镜的光学参数和技术指标。然后,介绍了非球面计算机控制光学表面成型(CCOS)技术及FSGJ非球面数控加工设备。最后,给出了非球面研磨阶段检测用的轮廓测量法和离轴凸非球面抛光阶段检测用的背部透射零位补偿检测法,并对背部透射零位补偿检测中离轴凸非球面反射镜光轴精度的控制技术进行了研究。检测结果表明:采用背部透射零位补偿检测法检测得到的离轴凸非球面反射镜的面形精度为0.017λ(均方根值,λ=0.632 8μm);用Leica经纬仪测量反射镜的光轴精度其结果达到9.4″,满足光学设计技术指标要求。

Fabrication and testing of precise off-axis convex aspheric mirror

To improve the fine surface figure accuracy and optical axis accuracy of an off-axis convex aspheric mirror, the fabrication and testing technologies of the off-axis convex aspheric mirror were studied. Firstly, a Three Mirror Anastigmat (TMA) optical system and the specification requirements of the second off-axis convex aspheric mirror in the TMA optical system were presented. Then, the technique of Computer-controlled Optical Surfacing(CCOS)for manufacturing the aspheric mirror and the FSGJ numerical control machine for processing aspheric surface were introduced. Finally, the contour testing in a lapping stage and the back transmission null testing in a polishing stage for the convex aspheric mirror were described, and the controlling technology for the optical axis accuracy of off-axis convex aspheric mirror was studied. The testing results indicate that the surface figure accuracy and the optical axis accuracy of the off-axis convex aspheric mirror are 0.017λ RMS and 9.4″,respectively. All the specifications of the off-axis convex aspheric mirror can meet the requirements of the optical design.