激光差动共焦曲率半径测量系统的研制

Development of laser differential confocal radius measurement system

针对国内高精度曲率半径计量需求,研制一套激光差动共焦曲率半径测量系统。该系统采用差动共焦定焦技术,利用轴向光强响应曲线的过零点精确对应物镜聚焦焦点这一特性,借助过零点对被测件的猫眼和共焦位置进行精密瞄准定位,通过干涉测长技术获取两点间的距离,继而实现曲率半径的高精度测量。该测量系统的机电控制由主控软件完成,可实现机电扫描、数据采集及数据处理,自动化程度高。实验证明,该系统定焦灵敏度高,受环境波动影响小,测量精度可达3×10-6,满足了高精度曲率半径的计量需求。

Aiming at the demand of high-precision radius metrology, a laser differential confocal radius measurement system is designed. Based on the property that the zero crossing point of a differential confocal intensity curve corre-sponds to the focus of the objective, the system uses the zero-crossing point to precisely identify the cat-eye and con-focal positions of the tested device, and uses an interferometer to measure the distance between the two positions and achieve high-precision measurement of radius of curvature. The electrical control of the measurement system is real- ized with the main control software, which can accomplish axial scanning, data acquisition and data processing. Experimental results show that the system is less subject to environmental fluctuations and the measurement accuracy reaches at 3×10^-6, and the system meets the demand of high-precision metrology of radius of curvature.