Characteristics of laser scanning confocal microscopes for surface texture measurements

Abstract

Due to the complexity of the surface topography, accurate surface characterization requires three-dimensional (3D) surface measurements. Confocal laser scanning microscopy (CLSM) is a non-destructive and versatile technique for quantifying 3D surfaces. The response of measurement quality to variations in CLSM hardware settings and specimen properties has been investigated. Through these investigations, certain criteria have been developed to select the optimal CLSM settings to minimize image noise, maximize contrast and resolution for reliable and accurate 3D surface measurements. The surface measurement results were then compared with those obtained from the stylus instrument, phase shifting interferometer (PSI) and the coherence scanning interferometer (CSI). With the optimal hardware settings, CLSMs proved to be an appropriate instrument for measuring moderately rough to rough surfaces regardless of surface reflectivity or surface finish. It exhibits versatility for measuring surfaces of complex geometry, which is needed in the engineering field. Moreover, preparation of the sample is not necessary.