title: Non-Contact Surface Roughness Measurement by Implementation of a Spatial Light Modulator.
abstract: The surface structure, especially the roughness, has a significant influence on numerous parameters, such as friction and wear, and therefore estimates the quality of technical systems. In the last decades, a broad variety of surface roughness measurement methods were developed. A destructive measurement procedure or the lack of feasibility of online monitoring are the crucial drawbacks of most of these methods. This article proposes a new non-contact method for measuring the surface roughness that is straightforward to implement and easy to extend to online monitoring processes. The key element is a liquid-crystal-based spatial light modulator, integrated in an interferometric setup. By varying the imprinted phase of the modulator, a correlation between the imprinted phase and the fringe visibility of an interferogram is measured, and the surface roughness can be derived. This paper presents the theoretical approach of the method and first simulation and experimental results for a set of surface roughnesses. The experimental results are compared with values obtained by an atomic force microscope and a stylus profiler.
authors.affiliation: Institute for Measurement Systems and Sensor Technology, Technische Universität München, Theresienstrasse 90, 80333 Munich, Germany. l.aulbach@tum.de.
authors.forename: Laura
authors.initials: L
authors.lastname: Aulbach
authors.affiliation: ETSI Minas y Energía, Universidad Politécnica de Madrid, Rios Rosas 21, 28003 Madrid, Spain. felixjose.salazar@upm.es.
authors.forename: Félix
authors.initials: F
authors.lastname: Salazar Bloise
authors.affiliation: Institute for Measurement Systems and Sensor Technology, Technische Universität München, Theresienstrasse 90, 80333 Munich, Germany. min.lu@tum.de.
authors.forename: Min
authors.initials: M
authors.lastname: Lu
authors.affiliation: Institute for Measurement Systems and Sensor Technology, Technische Universität München, Theresienstrasse 90, 80333 Munich, Germany. a.w.koch@tum.de.
authors.forename: Alexander W
authors.initials: AW
authors.lastname: Koch
keywords: fringe visibility; liquid crystal device; non-contact method; roughness measurement; spatial light modulator