Design of an optical probe for testing surface roughness and micro-displacement

This paper presents a practical monitoring tool for measurements of surface roughness and micro-displacement. An optical probe of the methods based on light scattering for measuring surface roughness and optical triangulation for measuring mi cro-displacement is described. The proposed technique all ows evaluation of surface roughness and micro-displacement of specimen by u sing just one device. The theoretical models of surface roughness and micro -displacement measurements have been established for the probe. The measuri ng principles applied in the design are described in detail and the validit y of the design is demonstrated by experimental evaluations. The experiment al results show that, for specimens with surface roughnesses R-a in the ran ge from 0.005 mum to 0.1 mum, micro-displacement measurements in the linear range of +/- 300 mum can be obtained. (C) 2001 Elsevier Science Inc. All r ights reserved.