SURFACE DEFECT MEASUREMENT METHOD BASED ON SPECTRAL CONFOCAL SENSOR

摘要

A surface defect measurement method based on a spectral confocal sensor, and an apparatus therefor. The measurement method comprises: mounting a plane mirror on an angular displacement stage, setting the tilt angle of the plane mirror (101), adjusting the distance between a spectral confocal sensor and the plane mirror (102), completing acquisition of spectral peak intensity data at the set tilt angle (103), and adjusting the angular displacement stage to obtain a different tilt angle, until acquisition of spectral peak intensity data at all specified tilt angles is completed (104); constructing a "steepness-distance-spectral peak intensity" characteristic curve (105); scanning and measuring a workpiece to be measured (106), and acquiring spectral peak intensity data of light reflected back from the surface of the workpiece to be measured (107), calculating the reflectivity of the measured point by the spectral peak intensity data in combination with the "steepness-distance-spectral peak intensity" characteristic curve (108); setting a reflectivity threshold, and identifying an area having an abrupt change in reflectivity by the set reflectivity threshold (110), to distinguish a defect area from a normal area, and completing defect locating and contour extraction (111). The measurement method provides a new method for the detection of surface defects of optical elements by establishing a mathematical model between the spectral peak intensity and the surface reflectivity and locating surface defects by means of the reflectivity.