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Applied Optics

Applied Optics


  • Editor: James C. Wyant
  • Vol. 47, Iss. 21 — Jul. 20, 2008
  • pp: 3968–3972

Application of the astigmatic method to the thickness measurement of glass substrates

Chien-Hung Liu and Zong-Han Li  »View Author Affiliations

Applied Optics, Vol. 47, Issue 21, pp. 3968-3972 (2008)

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We developed a high accuracy thickness measurement system for glass substrates based on the optical design of the astigmatic method. The astigmatic optical system includes a laser diode, a cylindrical lens, a convex lens, and a quadrant detector. This method measures the astigmatic focusing error signal induced from the measured glass placed in the astigmatic optical system. The astigmatic focusing error signal is converted into the thickness of the glass substrate. The proposed glass thickness measurement system is verified by using a coordinate measuring machine (CMM). The accuracy of the proposed system is 0.2 μm , with a standard deviation of 0.7 μm within the thickness measuring range of 1.2 mm .

© 2008 Optical Society of America

OCIS Codes
(120.0120) Instrumentation, measurement, and metrology : Instrumentation, measurement, and metrology
(120.0280) Instrumentation, measurement, and metrology : Remote sensing and sensors
(120.2830) Instrumentation, measurement, and metrology : Height measurements
(120.3930) Instrumentation, measurement, and metrology : Metrological instrumentation
(120.3940) Instrumentation, measurement, and metrology : Metrology

ToC Category:
Instrumentation, Measurement, and Metrology

Original Manuscript: May 23, 2008
Manuscript Accepted: June 26, 2008
Published: July 18, 2008

Chien-Hung Liu and Zong-Han Li, "Application of the astigmatic method to the thickness measurement of glass substrates," Appl. Opt. 47, 3968-3972 (2008)

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