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Proceedings Paper

Diffraction analysis and evaluation of a focus-error detection scheme for an optical profilometer
Author(s): Chunlan Yang; Zhaobang Pu; Huijie Zhao
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Paper Abstract

A high resolution non-contact optical sensor for surface roughness has been developed. The principle of the sensor is based on the dynamic focusing in combination with astigmatic method, a popular focus-error detection approach. The measuring principle of the method and the optical system arrangement are described in detail firstly. Then, a mathematical model of the system based on Fresnel diffraction theory is derived. According to the model, a plot of the focus error signal (FES) versus the misfocusing is easily got. The effect of various system parameters on the FES is discussed, and this is very useful for system optimization. Besides, results of numerical calculation, namely optical field distributions on the quadrant photodetector surface at different misfocusing, are presented.

Paper Details

Date Published: 9 October 2000
PDF: 5 pages
Proc. SPIE 4221, Optical Measurement and Nondestructive Testing: Techniques and Applications, (9 October 2000); doi: 10.1117/12.402613
Show Author Affiliations
Chunlan Yang, Harbin Institute of Technology (China)
Zhaobang Pu, Harbin Institute of Technology (China)
Huijie Zhao, Harbin Institute of Technology (China)


Published in SPIE Proceedings Vol. 4221:
Optical Measurement and Nondestructive Testing: Techniques and Applications
FeiJun Song; Frank Chen; Michael Y.Y. Hung; H.M. Shang, Editor(s)

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