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Proceedings Paper

A novel confocal line scanning sensor
Author(s): Sirichanok Chanbai; Georg Wiora; Mark Weber; Hubert Roth
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Paper Abstract

Optical methods, including confocal microscopes, are widely used for measurements of surface topography. The knowledge of surface morphology and roughness parameters is crucial for many applications, i.e. in industrial and automotive environment, in tribology, wear and functionality prediction. However, confocal microscopy has a limited field of view. A time consuming stitching process is required for extending to long profile lines measurement. Therefore, in this paper we present a novel concept of a Confocal Line Scanning Sensor (CLSS) to cover theoretically infinite profile lengths. The new technique is proposed with no moving parts required for axial scanning, and it has a simpler setup than those of Chromatic Confocal Sensor (CCS). The idea is to produce a stack of focal points on an inclined plane covering a certain axial measurement range. Therefore, by scanning the stack of focal points in lateral direction we can realize a long profile line. By doing that we expect to achieve shorter scanning time, while providing high lateral and axial resolution by using a true confocal principle. A long profile line of a few ten millimeters with a lateral resolution in sub-micrometer range and an axial resolution in tens of nanometers can be expected. Moreover, this concept is easily extensible to an areal measurement. Among other key components, a new design of the pinhole mask has been developed. We design it to produce an inclined focal line with optimum optical parameters. Optimization of the pinhole design fulfills two objectives; minimizing its size by allowing optimal reflected-light intensity, and minimizing crosstalk between nearby pinholes. Further detail of the pinhole design is beyond a scope of this paper. In this paper an overview of the new concept is presented, accompanied by validation of first experimental results.

Paper Details

Date Published: 22 May 2009
PDF: 8 pages
Proc. SPIE 7378, Scanning Microscopy 2009, 737822 (22 May 2009); doi: 10.1117/12.821205
Show Author Affiliations
Sirichanok Chanbai, NanoFocus AG (Germany)
Georg Wiora, NanoFocus AG (Germany)
Mark Weber, NanoFocus AG (Germany)
Hubert Roth, Univ. of Siegen (Germany)

Published in SPIE Proceedings Vol. 7378:
Scanning Microscopy 2009
Michael T. Postek; Michael T. Postek; Michael T. Postek; Dale E. Newbury; Dale E. Newbury; Dale E. Newbury; S. Frank Platek; S. Frank Platek; S. Frank Platek; David C. Joy; David C. Joy; David C. Joy, Editor(s)

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