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Proceedings Paper

Alignment methods for ultraprecise deflectometric flatness metrology
Author(s): Gerd Ehret; Michael Schulz; Arne Fitzenreiter; Maik Baier; Wolfgang Jöckel; Manuel Stavridis; Clemens Elster
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Paper Abstract

At the Physikalisch-Technische Bundesanstalt (PTB) two new scanning deflectometric systems (Deflectometric Flatness Reference: DFR) were installed for measuring topographies of nearly flat surfaces with sub-nanometre uncertainty. The two systems can measure the form of horizontally and vertically orientated specimens with a diameter of up to 700 mm. The systems are based on different deflectometric procedures, the so-called direct and the difference deflectometry. With the flatness measuring systems, an uncertainty down to 0.1 nm (depending on the specimen and its peak-to-valley) is being aimed at for the 95% coverage interval. Virtual experiments show that the optical and mechanical components must be aligned in the arcsecond range in order to achieve errors for the topography in the sub-nanometre range. In this paper we describe the setup of the new DFR system for horizontally orientated specimens in detail and show methods and experimental results for an accurate alignment of the optical and mechanical components. We present an accurate alignment strategy for ultraprecise deflectometric measurements and show a measurement of a section at a horizontally orientated specimen.

Paper Details

Date Published: 26 May 2011
PDF: 8 pages
Proc. SPIE 8082, Optical Measurement Systems for Industrial Inspection VII, 808213 (26 May 2011); doi: 10.1117/12.889325
Show Author Affiliations
Gerd Ehret, Physikalisch-Technische Bundesanstalt (Germany)
Michael Schulz, Physikalisch-Technische Bundesanstalt (Germany)
Arne Fitzenreiter, Physikalisch-Technische Bundesanstalt (Germany)
Maik Baier, Physikalisch-Technische Bundesanstalt (Germany)
Wolfgang Jöckel, Physikalisch-Technische Bundesanstalt (Germany)
Manuel Stavridis, Physikalisch-Technische Bundesanstalt (Germany)
Clemens Elster, Physikalisch-Technische Bundesanstalt (Germany)

Published in SPIE Proceedings Vol. 8082:
Optical Measurement Systems for Industrial Inspection VII
Peter H. Lehmann; Wolfgang Osten; Kay Gastinger, Editor(s)

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