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Proceedings Paper

Flatness measurement by UV moire
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Paper Abstract

A moire method using phase shifting technique is proposed for a flatness measurement, with highly accurate and fast measurement time. Two new methods are suggested for the elimination of the reflected light from the back plane of the glass substrate and for the reduction of contour line errors caused by waviness or warp of the sample surface. The former is UV moire technique and the latter is angle error reduction technique. In the UV moire technique a light of the 313nm wavelength is used for generating a moire. The light is able to eliminate the reflection from the back plane of the Liquid Crystal Display (LCD) glass substrate because it is absorbed inside the glass. The angle error reduction technique is to extrapolate data, which are measured in different distance between grating and sample, because the angle error is proportional to the distance between grating and sample. Using these two techniques, the proposed system realizes less than 0.6 microns in accuracy, while the conventional system is more than 10 microns in accuracy.

Paper Details

Date Published: 4 October 2001
PDF: 8 pages
Proc. SPIE 4564, Optomechatronic Systems II, (4 October 2001); doi: 10.1117/12.444102
Show Author Affiliations
Hisatoshi Fujiwara, Yamatake Co. (Japan)
Yukitoshi Otani, Tokyo Univ. of Agriculture and Technology (Japan)
Toru Yoshizawa, Tokyo Univ. of Agriculture and Technology (Japan)

Published in SPIE Proceedings Vol. 4564:
Optomechatronic Systems II
Hyungsuck Cho, Editor(s)

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