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Applied Optics

Applied Optics


  • Editor: Joseph N. Mait
  • Vol. 53, Iss. 20 — Jul. 10, 2014
  • pp: 4604–4610

Quadrature laser interferometer for in-line thickness measurement of glass panels using a current modulation technique

Jong-Ahn Kim, Chu-Shik Kang, Tae Bong Eom, Jonghan Jin, Ho Suhng Suh, and Jae Wan Kim  »View Author Affiliations

Applied Optics, Vol. 53, Issue 20, pp. 4604-4610 (2014)

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A thickness measurement system is proposed for in-line inspection of thickness variation of flat glass panels. Multi-reflection on the surfaces of glass panel generates an interference signal whose phase is proportional to the thickness of the glass panel. For accurate and stable calculation of the phase value, we obtain quadrature interference signals using a current modulation technique. The proposed system can measure a thickness profile with high speed and nanometric resolution, and obtain higher accuracy through real-time nonlinear error compensation. The thickness profile, measured by a transmissive-type experimental setup, coincided with a comparative result obtained using a contact-type thickness measurement system within the range of ±40nm. The standard deviations of the measured thickness profiles and their waviness components were less than 3 nm with a scanning speed of 300mm/s.

© 2014 Optical Society of America

OCIS Codes
(120.0120) Instrumentation, measurement, and metrology : Instrumentation, measurement, and metrology
(120.3180) Instrumentation, measurement, and metrology : Interferometry
(120.4630) Instrumentation, measurement, and metrology : Optical inspection

ToC Category:
Instrumentation, Measurement, and Metrology

Original Manuscript: April 1, 2014
Revised Manuscript: May 26, 2014
Manuscript Accepted: June 1, 2014
Published: July 10, 2014

Jong-Ahn Kim, Chu-Shik Kang, Tae Bong Eom, Jonghan Jin, Ho Suhng Suh, and Jae Wan Kim, "Quadrature laser interferometer for in-line thickness measurement of glass panels using a current modulation technique," Appl. Opt. 53, 4604-4610 (2014)

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