非球面碳化硅反射镜的加工与检测

Fabrication and testing of aspheric silicon carbide mirror

为了获得高精度非球面碳化硅(SiC)反射镜,对非球面碳化硅反射镜基底以及改性后碳化硅反射镜表面的加工与检测技术进行了研究。介绍了非球面计算机控制光学表面成型(CCOS)技术及FSGJ-2非球面数控加工设备。采用轮廓检测法和零位补偿干涉检测法分别对碳化硅反射镜研磨和抛光阶段的面形精度进行了检测,并采用零位补偿干涉检测法及表面粗糙度测量仪对最终加工完毕的碳化硅反射镜的面形精度和表面粗糙度进行检测。测量结果表明:各项技术指标均满足设计要求,其中非球面碳化硅(SiC)反射镜实际使用口径内的面形精度(RMS值)为0.016λ(λ=0.632 8μm),表面粗糙度(RMS值)为0.85 nm。

In order to manufacture a precise aspheric silicon carbide （SIC） mirror, the fabrication and testing technologies for the substrate of the SiC mirror and the surface of the modified SiC mirror were studied. The technique of the computer-controlled optical surfacing for manufacturing aspheric mirror and the FSGJ-2 numerically-controlled machine for processing aspherie surface are introduced. The methods of contour testing and null testing were adopted respectively to measure the surface accuracy of aspheric mirror while SiC mirrors were grinded and polished. The surface figure and roughness of the final aspheric SiC mirror were tested with null testing and surface roughness tester. The testing results indicate that all the specifications meet the requirements of design. The surface profile accuracy of the aspheric SiC mirror is 0. 016λ RMS and the surface roughness of the mirror is 0.85 nm RMS.