Affiliations: [a] Ministry of Education Key Laboratory of Testing Technology for Manufacturing Process, Southwest University of Science and Technology (SWUST), Mianyang, China
| [b] Department of Instrumentation, School of Mechanical Engineering, Huazhong University of Science and Technology (HUST), Wuhan, China
Correspondence:
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Corresponding author. Guolu Ma, Ministry of Education Key Laboratory of Testing Technology for Manufacturing Process, Southwest University of Science and Technology (SWUST), Mianyang 621010, Sichuan, People’s Republic of China. E-mail: [email protected].
Abstract: In order to realize the online thickness measurement of thin films, an automatic film thickness measuring system was established, and its optical design, mechanical structure design, as well as the analysis and evaluation of the optical aberration based on the software of ZEMAX were researched. Project two laser beams vertically onto the same position of the film respectively from upper and lower side there will be two round spots on the film surfaces, image the two spots onto the image detector the film thickness can be got according to the relationship between the measured film thickness and the orthocenters of the upper and lower imaging spots. During the calibrating experiment, a nonlinear correction method was proposed. Experimental results indicated that the measurement precision is±1 μm. After a period time of three months online working, the system was proven to have the characteristics of good stabilization, high precision and convenient maintenance.