For the measuring demand of surface coating quality, and to keep the surface to be measured from being damaged, laser is adopted as a optical probe. When contactless measurement of the object surface coating uniformity is carried out, a laser beam illuminates the object surface to be tested. By analysis of the reflected light signal from the random surface, relation between the intensity of reflected light and surface coating uniformity is obtained. To decrease the error caused by the dithering of source, laser source is fitted at a certain height above the surface to be measured. By moving the optical table, light spot scans over the object surface. Real-time statistic of the data collected is made by computer, and then deviation report of surface coating uniformity is acquired. Experiment results prove that the measurement system is simple, stable and reliable, with high speed of response and good interference killing feature. Measurement accuracy of the system achieves 5μm, and error of measurement value is less than ±1% within an operation scope from 1 μm to 50 μm. The method has the advantage of simple structure and intuitionistic principle, and it can detect online conveniently.

Date Published: 19 February 2008
PDF: 6 pages
Proc. SPIE 6625, International Symposium on Photoelectronic Detection and Imaging 2007: Related Technologies and Applications, 66251Q (19 February 2008); doi: 10.1117/12.791228

Published in SPIE Proceedings Vol. 6625:
International Symposium on Photoelectronic Detection and Imaging 2007: Related Technologies and Applications
Liwei Zhou, Editor(s)