大口径凸非球面检验是非球面镜制造领域的难题之一。结合项目中一块相对孔径F/0.75, 口径为332mm凸抛物面副镜的研制实例, 在分析传统检验方法优缺点及适用性后, 针对性地提出了一种类Offner透射补偿检验的新方法。基于三级像差理论出发求解其初始结构, 使用Zemax软件分析与优化, 从设计结果上看, 此方法补偿精度很高, 有效地补偿了非球面的法线像差。用蒙特卡洛方法分析给出公差分配方案, 并研制出类Offner透射补偿器, 用于凸抛物面镜的面型检验, 表明此检验方法是完全可行的。实际加工完成后, 用4D干涉仪检测镜面的面形精度达到RMS=0.0183λ优于λ/50(λ=632.8nm)。

It’s very difficult for testing of a large convex aspheric surface in the area of aspheric optical surface manufacture. Based on analyzing classical testing methods, a new testing method of a convex parabolic mirror using lens for compensational tests is discussed with the diameter of 332mm and the relative aperture of F/0.5. The original configuration for similar Offner compensator in the optical path is derived from the third-order aberration theory, and the initial configuration is optimized by Zemax software. The initial design results of the method show that the aberration of aspheric surface is compensated effectively. Through optimizing the initial design to allocate the tolerance of parts by Monte Carlo analysis, the similar Offner compensator is fabricated for the manufacture and test of the aspheric surface, which shows that the method is entirely feasible. RMS of the convex parabolic surface given by 4D interferometer is better than λ/50(λ=632.8nm) and satisfy the technical indicators after manufacturing.