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Proceedings Paper

Measurement system for lens thickness based on low-coherent fiber-optic interferometry
Author(s): Li Chen; Junhua Wang; Min Xu
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Paper Abstract

A new non-contact and wide-range measurement system for lens thickness based on low-coherent interferometry was proposed in this paper. In this system the reference mirror was set moveable, and high-resolution grating ruler was utilized to record real-time position of mirror. Then lens central thickness was calculated on the basis of the relative distance between two interference fringes’ peak. Compared with the traditional thickness measurement technology based on low-coherent interferometry the new method has made great progresses. Firstly beam splitting and interference were separated by use of several fiber couplers which realized appropriate intensity ratio of probe beam and reference beam, and enhanced the contrast of interference fringes. Then zoom lens was designed to improve intensity coupling efficiency between the fiber system and lens system. Finally conversion from optical signal to electronic signal was accomplished by using balance detection, which was good for improving the signal-to-noise ratio. In this paper, firstly the basic principle of measuring device was put forward, namely low-coherent interference technique. Then design of the measuring device and solution for the main problems was introduced in detail. Experimental results of device was given in the end of article, which proved that the relative error of measurement was less than 0.05%.

Paper Details

Date Published: 19 October 2016
PDF: 8 pages
Proc. SPIE 10155, Optical Measurement Technology and Instrumentation, 1015515 (19 October 2016); doi: 10.1117/12.2245697
Show Author Affiliations
Li Chen, Fudan Univ. (China)
Junhua Wang, Fudan Univ. (China)
Min Xu, Fudan Univ. (China)

Published in SPIE Proceedings Vol. 10155:
Optical Measurement Technology and Instrumentation
Sen Han; JiuBin Tan, Editor(s)

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