Development of an Optical Stylus Displacement Sensor for Surface Profiling Measurement

Abstract

Most optical styluses composed of laser diode and objective lens are troubled with signal noise when being traversed over engineering surfaces. The main cause of that signal noise can be attributed to laser speckle included in the reflected light from the object surface. It has been strongly demanded to decrease the influence of such speckle noise on the displacement signal of those optical styluses. In this study, a novel optical measurement system was proposed for a new optical stylus that has the speckle noise removal function. By using the newly developed optical stylus, surface profiles with less high frequency components were obtained for two kinds of machined surfaces with different surface textures. Applicability of the developed optical stylus to the profile measurement of engineering surfaces was experimentally verified.