Tolerance-on-sphere-radius-for-the-calibration-of-the-transfer-function-of-coherence-scanning-interferometry.pdf (2.21 MB)
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Tolerance on sphere radius for the calibration of the transfer function of coherence scanning interferometry

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conference contribution
posted on 08.09.2017 by Rong Su, Jeremy Coupland, Yang Wang, Richard K. Leach
Although coherence scanning interferometry (CSI) commonly achieves a sub-nanometre noise level in surface topography measurement, the absolute accuracy is difficult to determine when measuring a surface that contains varying local slope angles and curvatures. Recent research has shown that it is possible to use a single sphere with a radius much greater than the source wavelength to calibrate the three-dimensional transfer function of a CSI system. A major requirement is the accurate knowledge of the sphere radius, but the three-dimensional measurement of a sphere with nanometre level uncertainty is a highly challenging metrology problem, and is not currently feasible. Perfect spheres do not exist and every measurement has uncertainty. Without having a quantitative understanding of the tolerance of the sphere radius, the calibration method cannot be used confidently for calibration of the transfer function of a CSI system that may be used in research laboratories or industry. In this paper, the effects of the tolerance of the radius of the calibration sphere on surface topography measurements are quantitatively analysed through a computational approach. CSI measurements of spherical, sinusoidal and rough surfaces are investigated in the presence of various degrees of radius error. A lookup table that relates the surface height error as a function of the radius error and surface slope angle is provided. The users may estimate the required tolerances of the sphere radius for their specific surface measurements if this calibration approach is used. The output of this paper provides a feasibility analysis for this calibration method for further development and applications.

Funding

This work was supported by the Engineering and Physical Sciences Research Council (grant EP/M008983/1) and EMPIR (15SIB01: FreeFORM). EMPIR is jointly funded by the EMPIR participating countries within EURAMET and the European Union.

History

School

  • Mechanical, Electrical and Manufacturing Engineering

Published in

OPTICAL MEASUREMENT SYSTEMS FOR INDUSTRIAL INSPECTION X

Volume

10329

Citation

SU, R. ... et al, 2017. Tolerance on sphere radius for the calibration of the transfer function of coherence scanning interferometry. IN: Lehmann, P., Osten W. and Goncalves Jr, A.A. (eds). Optical Measurement Systems for Industrial Inspection X, Proc. of SPIE Vol. 10329, 103290L (June 26 2017); doi: 10.1117/12.2272041.

Publisher

© SPIE

Version

VoR (Version of Record)

Publication date

2017

Notes

Copyright 2017 Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.

ISBN

9781510611030

ISSN

0277-786X

Book series

Proceedings of SPIE;10329

Language

en

Exports