非球面光学元件面形误差边缘处理方法(特邀)

Method of edge control on surface error in aspherical optics (invited)

计算机控制光学元件面形修复(Computer Control Optics Surfacing, CCOS)需要通过计算驻留时间,反复迭代,从而得到更小的误差。因为干涉测试过程中边缘面形测试的条件限制,只能得到更小孔径的误差分布图,所以面形的预测性延拓是磁流变抛光、离子束抛光等加工方式的基础技术。基于面形误差的相似性和边缘误差的连续性为出发点,开发了采用基于Zernike拟合和Laplace方程配合的方法进行光学元件面形误差边缘延拓技术。开展了相关理论分析,设计相关算法并实现了延拓过程,延拓结果符合面形相似形和连续性的加工要求,采用直接法和残余误差计算方法对延拓结果进行评估,结果证明了延拓方法的有效性。

Computer Control Optics Surfacing(CCOS) requires the surface error map for iterative processing to get low error by dwellingtime caculation. Because the smaller aperture of error map will be gotten in interferometer on edge of optic work part, so the predictive extrapolation of surface error map is the basic technology of magneto-rheological polishing, ion beam polishing and other machining methods. Based on the similarity of surface error and the continuity of edge error, the extrapolation of surface error method was developed, based on Zernike fitting and Laplace equation. The theory was studied and the algorithm was developed to get extrapolation of surface error map, fulfilling the similarity and the continuity. The result was evaluated by surface error comparison and residual error calculation, which was proved to be effective.