Firstly theory and characteristics of light passing film are analyzed. Then, a new type of photoelectric film detection system with some components, such as lens, a splitting prism, a filter, a new photoelectric detector, and so on are also analyzed.The system uses a high-precision bridge comparative method to send optical signals shoot by lamp-house to the beamsplitter through an optical system composed with lens. The beamsplitter divides signals into two symmetrical ways respectively passing symmetrical optical systems composed with filters, diaphragms and so on, in which one enters the test film and the other enters referenced film. The test film and the referenced one make different decays for two signals, and then optical signals are transformed into electric signals which are amplified by a low temperature drift amplifier after being compared in high-precision electric bridge. At last the thickness values of film are displayed by displaying circuit. The system has a symmetrical structure and high test precision. We use this system to measure films practically and obtain experiment data results. Then we analyze the error and the results and present several important conclusions.

Date Published: 20 May 2009
PDF: 5 pages
Proc. SPIE 7283, 4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, 72831S (20 May 2009); doi: 10.1117/12.828683

Published in SPIE Proceedings Vol. 7283:
4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment
Yudong Zhang; James C. Wyant; Robert A. Smythe; Hexin Wang, Editor(s)