Confocal microscope method for curvature radius measurement of small lens
Confocal microscope method for curvature radius measurement of small lens
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DOI：
10.1117/12.966325
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发表时间：
2012-10
期刊：
影响因子：
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通讯作者：
Qian Liu;Weichuan Yang;Pengyue Wu;Daocheng Yuan
中科院分区：
文献类型：
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作者：
Qian Liu;Weichuan Yang;Pengyue Wu;Daocheng Yuan
随着光学器件的小型化，透镜的尺寸变得更小。曲率半径是球面透镜的重要参数，其测量在小型透镜的制造中具有重要意义。本文提出用共焦显微镜法测量球面透镜，特别是小球面透镜的曲率半径。该方法的装置由共焦显微镜和光栅条组成。共焦显微镜的探测器在球面处于“猫眼”位置或共焦位置时输出最大。猫眼到共焦点的距离就是球面的曲率半径。该方法适用于凹曲面和凸曲面。对探测器的轴向位移和横向位移响应进行了分析和仿真。并利用仿真结果对测量误差进行了估计。该装置采用0.2NA的10倍显微镜物镜和0.04mm直径的针孔，并且进行实验以测量3mm直径的标准光学球的半径。结果误差小于0.01mm。结果表明，采用更高的数值孔径和更精确的运动平台可以将误差减小到0.001mm以内。
With the minimization of optical devices, the size of lens becomes much smaller. As a crucial parameter of spherical lens, the measurement of curvature radius is valuable in small lens manufacturing. In this paper, confocal microscope method is proposed to measure curvature radius of spherical lens, especially small spherical lens. The setup of this method consists of a confocal microscope and a grating bar. The detector of confocal microscope gives maximum output when the spherical surface is placed at “cat’s eye” position or confocal position. The distance between cat’s eye and confocal position is the curvature radius of spherical surface. This method is suitable for both concave and convex surface. The response of detector to axial and traversal displacement is analyzed and simulated. And the measurement error is estimated with the simulated results. The setup employed a 10x microscope objective of 0.2 NA and pinhole of 0.04mm diameter, and experiment was conducted to measure the radius of a standard optical ball of 3mm diameter. The error of result is less than 0.01mm. It’s concluded that the error could be reduced less than 0.001mm with higher numerical aperture and more precise movement stages.