基于数字全息扫描成像的划痕缺陷全场三维测试

Full-Field Three-Dimensional Test for Scratch Defects Using Digital Holographic Scanning Imaging System

为实现光学元件表面疵病的三维全场测量,提出了一种数字全息显微扫描成像的检测方法。该方法基于数字全息角谱数值重建算法,获得光学元件表面划痕的相位分布,通过扫描拼接实现划痕的全场测量;然后,在数字全息显微实验装置的基础上增加二维精密扫描部件,对于宽50μm、深50 nm标准划痕,测得其宽度为49.2μm、深度为48.9 nm,同时拼接获得该划痕的全场三维形貌。实验表明:该检测方法可实现大视场划痕缺陷的全场三维测试,其宽度和深度测量的相对误差分别为1.6%和2.2%。

To obtain three-dimensional full-field measurements of the surface defects of optical elements,a method of digital holographic microscopic scanning imaging is proposed in this study.Based on the numerical reconstruction algorithm of digital holography angle spectrum,the phase distribution of scratches on the surface of optical elements is obtained,and the whole-field measurement of scratches is obtained using the principle of scanning and splicing.Then,a two-dimensional precision scanning component is developed based on the digital holographic micro-experimental device.For the standard scratch having a width of 50μm and a depth of 50 nm,we measure a width of 49.2μm and a depth of 48.9 nm.Next,the full-field three-dimensional morphology of the scratch is obtained by splicing.The experimental results show that the defect panorama with larger scale can be obtained by phase stitching.The relative errors of width and depth are 1.6%and 2.2%,respectively.