平差理论在大口径光学元件轮廓检测中的应用

为了更好地进行大口径光学元件轮廓测量,以激光跟踪仪作为测量的工具,引入测量平差理论对测量数据进行处理,以提高光学元件毛坯制作、铣磨加工阶段的轮廓测量精度。首先,对拟合误差的公式进行了推导,得出影响拟合精度的因素;之后,对于大口径元件轮廓测量的具体检测模型提出了提高拟合精度的方法;最后,对于实际的2 m量级口径的SiC主镜进行了实际的测量与拟合,并从F数、拟合残差、结构函数等角度分析了平差结果。所提出的方法对于大口径元件的加工检测具有较好的指导意义。

Application of adjustment theory in large aperture mirror surface profile metrology

With the objective of collecting more accurate results and improving the testing accuracy during the mirror substrate manufacturing and generating phase, the adjustment theory to measure the large aperture mirror profile based on the instrument of laser tracker was adopted. Firstly, the adjustment theory was deduced and the main influence factors for the accuracy of the profile metrology was obtained, then the fitting model of profile of the large aperture mirror was established. And then a method to improve the metrology accuracy for the fitting model was proposed. Lastly, the method was applied to the two meter class in diameter substrate of SiC primary mirror, and the theory was verified from the different aspects of F number, residual error and structure function. The proposed method could be showed as a guideline to the metrology and manufacture of large aperture mirror.