7 November 2005 Three-dimensional shape measurement using focus method by using liquid crystal grating and liquid varifocus lens
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Proceedings Volume 6000, Two- and Three-Dimensional Methods for Inspection and Metrology III; 60000J (2005); doi: 10.1117/12.633147
Event: Optics East 2005, 2005, Boston, MA, United States
Abstract
This paper describes a surface profile measurement using a varifocus lens by an optical sectioning. The focus method is utilized for a uni-axis optical system of projection and observation. The varifocus lens is mounted on between a liquid crystal grating and a projection lens. A focus length can be continuously varied from a concave to a convex shape by changing the liquid pressure. The contrast of projected pattern onto the sample is approximated the Gauss distribution along the distance and indicates sharpest at the focused plane. It is possible to analyze the contrast distribution by a grating projected method using a liquid crystal grating with 4 steps phase-shifting method. The liquid crystal grating is powerful tool to make arbitrary intensity and frequency distribution. Surface profiles of mechanical parts have been measured to demonstrate for this method.
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Yasuhiro Mizutani, Ryoichi Kuwano, Yukitoshi Otani, Norihiro Umeda, Toru Yoshizawa, "Three-dimensional shape measurement using focus method by using liquid crystal grating and liquid varifocus lens", Proc. SPIE 6000, Two- and Three-Dimensional Methods for Inspection and Metrology III, 60000J (7 November 2005); doi: 10.1117/12.633147; https://doi.org/10.1117/12.633147
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KEYWORDS
Liquids

Liquid lenses

Liquid crystals

3D metrology

Phase shifting

Phase shifts

Distance measurement

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