Chromatic Confocal Microscopy

Abstract

Abstract. Chromatic confocal probes are single point optical sensors built around a confocal coaxial setting that use chromatic dispersion and decoding to obtain the surface distance. Such sensors are usually installed on scanning stages of surface texture measuring instruments, roundness instruments or coordinate measuring machines. Chromatic confocal probes can measure on, and through, transparent material, detect several interfaces between materials and, therefore, calculate thickness. The metrological characteristics of chromatic confocal probes are close to those of stylus probes and they are often used as a non-contact substitute on stylus profilometers.

Measurement uncertainty associated with chromatic confocal profilometry for 3D surface texture characterization of natural human enamel

“…Accordingly, recent research into nanometer scale surface changes of polished human enamel using confocal laser microscopy concluded that optimal characterization of acid mediated surface texture changes requires surface metrology instrumentation with lateral resolution less than 2.5 µm [3]. Chromatic Confocal profilometry is industry standard for optical surface metrology and is specifically recommended by the ISO 25178 international standard for non-contact 3D metrology [4,5]. However, the lateral resolution of chromatic confocal profilometers is limited by the sensor spot diameter varying from up to 24 microns and also by lateral mechanical scanning which introduces measurement noise during the movement of the x,y stage [6].…”

Morphology of fungal stains on paper characterized with multi‐scale and multi‐sensory surface metrology

“…The results of measuring inclusions in stain B, using LCA were puzzling, indicating loss of data. Non‐measured points can result from many causes, such as the surface height being above or below the measuring range, the focal point falling into a “hole,” the slop being too steep, or reflective/absorptive characteristics of the material (Blateyron, ). In case of fungal inclusions the areas of data “voids” corresponded to the shape and location of fungi.…”

Thermal and dimensional evaluation of a test plate for assessing the measurement capability of a thermal imager within nuclear decommissioning storage

“…The CCM consists of a chromatic confocal point probe sensor with a 12 mm measuring range mounted vertically (z) above a lateral (x, y) sample translation system. The plate was moved in a raster scan to build up a 2D grid of surface heights measured using the chromatic confocal principle [12].…”