为了增强高精度曲率半径测量仪器的抗环境干扰能力, 满足现场使用需求, 研制了一套基于光栅尺测长的激光差动共焦曲率半径测量系统。该系统利用差动共焦轴向光强响应曲线的过零点对应系统物镜聚焦焦点这一特性, 对被测样品的猫眼位置及共焦位置进行精确瞄准定位, 并借助光栅尺测长得到透镜猫眼位置与共焦位置之间的距离, 实现曲率半径的测量。实验表明, 该系统相对测量精度优于5×10-6, 满足高精度曲率半径测量的精度需求。

In order to enhance the environmental anti-interference capability for the radius of curvature (ROC) measurement and meet the requirements of use on the production spot, a laser differential confocal curvature measurement system with grating was developed, which used the property, that the zero point of a differential confocal intensity curve corresponds to the focus of objective, to precisely identify the cat-eye and confocal positions of the tested lens, and then used the grating to measure the distance between these two positions, thereby the high-precision measurement of ROC was achieved. Experimental results show that the system has an accuracy of better than 5×10-6. So it can meet the demand of high-precision measurement of ROC.