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Proceedings Paper

New interferometric method to locate aspheric in the partial null aspheric testing system
Author(s): Wei Tao; Liu Dong; Tian Chao; Zhang Lei; Yongying Yang
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Paper Abstract

The partial null interferometric aspheric testing technique, based on the Twyman-Green interferometer system, is very useful and of good versatility. In this technique, the under-test aspheric needs to be located precisely. Taking advantage of ray tracing and digital image processing technique, a new method to locate aspheric is proposed. Firstly, model and simulate the Twyman-Green interferometer system in the ray tracing software ZEMAX, find an optimal test position and generate an optimal referenced interferogram. Record the interferogram and make it a target for the experimental interferogram to achieve. At the same time, an experimental interferogram can be obtained by building the same testing system experimentally. Process the one-dimensional gray scale data in X-axis of the two interferograms, two curves, indicating the black and white change of the interference fringes, are obtained. By comparing the normalized X coordinates of the peaks of the two curves, we can determine whether the under-test aspheric is positioned well. In order to locate the aspheric precisely, the aspheric has to be moved repeatedly to get a perfect interferogram whose peaks of interference fringes match well with those of the target interferogram. An experiment for testing a paraboloid with diameter 100mm and asphericity 50μm is carried out. The result shows that this kind of locating method has an Accuracy of 3-5μm, which demonstrates that the method is practicable and high-precision.

Paper Details

Date Published: 15 October 2012
PDF: 6 pages
Proc. SPIE 8417, 6th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, 84173I (15 October 2012); doi: 10.1117/12.975110
Show Author Affiliations
Wei Tao, Zhejiang Univ. (China)
Liu Dong, Zhejiang Univ. (China)
Tian Chao, Zhejiang Univ. (China)
Zhang Lei, Zhejiang Univ. (China)
Yongying Yang, Zhejiang Univ. (China)


Published in SPIE Proceedings Vol. 8417:
6th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment
Yudong Zhang; Libin Xiang; Sandy To, Editor(s)

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