并行像散共焦微结构探测光学系统分析与设计

以提高光学系统对测点正焦位置辨识精度为目标分析设计并行像散共焦系统。设计基于远心光路,采用20倍长工作距显微物镜作为系统物镜,采用2片正交对称配置的薄柱面镜组建像散镜组取代探测光路中的管镜,通过对像散镜组参数优化实现探测曲线过零点灵敏度的最大化,并利用像散原理的差动算法有效抑制了光学系统各种噪声和漂移对像散光场稳定性的影响,获得了高灵敏度、高稳定性、较好一致性的全场探测曲线。通过大量实验证明了优化像散镜组参数对提升探测曲线灵敏度的作用,证明了并行像散光场探测曲线有良好的稳定性,全场测点的正焦位置辨识精度能够达到50 nm。

Analysis and design of the parallel astigmatic confocal optics system for detecting 3D micro-structure

The light path of the parallel astigmatic confocal system is analyzed and designed aiming at promoting the resolution of the in-focus position of the probing points.The design is based on telecentric light path and a 20X plan long-working-distance objective is used as the objective of the system.An astigmatic lens group,which substitutes the tube lens in the detection light path,is built with two exact uniform thin cylindrical lenses assembled orthogonally.The sensitivity of the detecting curves of the parallel astigmatic faculae is maximized by optimizing the configuration parameters of the astigmatic lens group.By means of the differential algorithm of the astigmatic principle,the interferences coming from the noises and drifts of light source and CCD(charge-coupled device) are restrained effectively,and the stabilization of the parallel astigmatic faculae is optimized.The whole field detecting curves with high sensitivity and stabilization and good uniform optical characteristics of both out-axis and in-axis faculae are achieved.A large number of experiments prove that optimizing the configuration parameters of the astigmatic lens group can enhance the sensitivity of the detecting curves,and the whole-field identification accuracy of in-focus position of the probing points can reach 50 nm in the parallel astigmatic confocal system.