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Proceedings Paper

Uncertainty of topography determination based on slope difference or curvature measuring systems in laboratory and industrial environments
Author(s): Michael Schulz
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Paper Abstract

In the past few years two form or topography measuring methods have been developed at PTB that are based on measuring the slope (angle) difference or the curvature, which both are intrinsic properties of the surface. In a laboratory environment the methods offer a very low uncertainty of measurement down to, or in part even below, the nanometer range. One of them is the Extended Shear Angle Difference method (ESAD), in which the angle difference signal of two surface points separated by a rather large shear is the basic measurement signal obtained with an autocollimation telescope. The other is Large Area Curvature Scanning (LACS) where the curvature values of the surface elements along a scan line are captured by a small interferometer. Error and uncertainty considerations are given for these methods which form the basis for determining the uncertainty which can be achieved under well optimized environmental conditions as necessary for tracing back and calibrating other measuring systems. Additionally, the uncertainty that can be reached in an industrial environment is discussed, and solutions are described to use these promising techniques also in such cases.

Paper Details

Date Published: 30 May 2003
PDF: 10 pages
Proc. SPIE 5144, Optical Measurement Systems for Industrial Inspection III, (30 May 2003); doi: 10.1117/12.500425
Show Author Affiliations
Michael Schulz, Physikalisch-Technische Bundesanstalt (Germany)

Published in SPIE Proceedings Vol. 5144:
Optical Measurement Systems for Industrial Inspection III
Wolfgang Osten; Malgorzata Kujawinska; Katherine Creath, Editor(s)

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