五棱镜扫描测量非球面二次系数方法研究

Research of Testing the Conic Constant of Aspheric Surface with Scanning Pentaprisms

提出了利用双五棱镜扫描求解大口径非球面二次系数的方法。该方法采用一束平行光通过五棱镜扫描大口径非球面，通过非球面的反射光将聚焦在非球面的光轴附近，通过测量被测非球面焦平面上光斑质心偏移光轴的轨迹求解二次系数。建立了光斑质心偏移轨迹和二次系数关系的数学模型，并分离调整误差如离焦和倾斜。在上述算法的基础上对五棱镜扫描法求二次系数进行了误差源分解，在误差容限范围内通过分离调整误差和去除非相关像差的影响得到了较高的二次系数测量精度。

Two scanning pentaprisms are used to measure the conic constant of large aspheric surface. The parallel rays through pentaprisms are used to scan the large aspheric surface. The ray reflected from asheric surface focuses near the optical axis. The conic constant of aspheric surface is calculated by measuring a series of positions of the focal spots. The reconstruction algorithm for conic constant is proposed. The misalignment such as defocus and tilt is separated in the algorithm. The error sources are evaluated in detail. The conic constant can be measured with high precision after separating the misalignments and uncorrelated aberration within error margin.