作者：阮昊洋¹, 李加福², 白娴靓³, 杜华², 罗明哲², 胡佳成¹

作者单位：1. 中国计量大学计量测试工程学院，浙江 杭州 310018;
2. 中国计量科学研究院，北京 100029;
3. 北京国科军友工程咨询公司，北京 100086

关键词：二元衍射;光谱共焦;位移测量;轴向色散

摘要：

为实现高精度、高轴向分辨率的光谱共焦显微位移测量，提出一种将二元衍射透镜引入测量系统的方法。该方法中二元衍射透镜相比于传统折射透镜色散线性度更好，且在消色差的同时减小单色像差特别是对测量影响较大的轴上球差的影响。在数据处理上采用中值滤波减小随机噪声对谱峰定位造成的影响，质心法和多项式拟合的方法分别减小峰值波长提取和标定曲线拟合的误差。实验选用白光光源，采用50×物镜和100×物镜分别和二元衍射透镜组合搭建系统，通过PI纳米位移台对系统进行标定和测量。实验结果表明，100×物镜系统测量精度更高，测得该系统在432~807 nm的波长范围内，测量范围为40 μm，系统的平均测量精度可达0.0462 μm，轴向分辨率优于0.2 μm，符合微小间距测量的要求。

Spectral confocal micro displacement measurement based on binary diffraction
RUAN Haoyang¹, LI Jiafu², BAI Xianliang³, DU Hua², LUO Mingzhe², HU Jiacheng¹
1. College of Metrology & Measurement Engineering, China Jiliang University, Hangzhou 310018, China;
2. National Institute of Metrology, Beijing 100029, China;
3. Beijing Guoke Junyou Engineering Consulting Co., Ltd., Beijing 100086，China
Abstract: In order to realize the measurement of spectral confocal micro displacement with high accuracy and high axial resolution, a method of introducing binary diffractive lens into the measurement system is proposed. In this method, the binary diffractive lens has better dispersion linearity than the traditional refractive lens, and reduces the monochromatic aberration while eliminating the chromatic aberration, especially the influence of on-axis spherical aberration, which has a great influence on the measurement. In data processing, median filtering is used to reduce the impact of random noise on spectral peak location. Centroid method and polynomial fitting method reduce the errors of peak wavelength extraction and calibration curve fitting respectively. In the experiment, white light source is selected, 50×objective lens and 100×objective lens are combined with binary diffractive lens respectively to build the system, and the system is calibrated and measured by PI nano displacement table. The experimental results show that the measurement accuracy of the 100×objective lens system is higher. The measurement range of the system is 40 μm in the wavelength range of 432-807 nm. The average measurement accuracy of the system can reach 0.0462 μm, and the axial resolution is better than 0.2 μm, which meets the requirements of small spacing measurement.
Keywords: binary diffraction;spectral confocal;displacement measurement;axial dispersion
2023, 49(2):34-41  收稿日期: 2022-08-15;收到修改稿日期: 2022-10-13
基金项目: 国家自然科学基金青年基金项目（52205579）；中国计量科学研究院基本科研业务费（AKYZZ2205）
作者简介: 阮昊洋(1998-),男,浙江宁波市人,硕士研究生,专业方向为几何量计量及空间尺寸精密测量技术
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