Sparse microdefect evaluation system for large fine optical surfaces based on dark-field microscopic scattering imaging

Abstract

It is considered challenging to evaluate the sparse microdefects of large optical surfaces because the microdefects are usually of microns while the test samples are of hundreds of millimeters. Most of the existing methods encounter problems such as uncertainty and inefficiency in eyeballing, inconsequence between laser source and international standard, limitation of detecting area, qualitative but not quantitative nor standard measurement of defects, etc. In this paper, a dark-field microscopic scattering imaging system for microdefects evaluation is introduced. The principle of the proposed surface microdefect evaluation system will be presented and the experiment results on evaluating numerous of test samples will be given.