High Speed Confocal 3D Profilometer: Design, Development, Experimental Results

Abstract

Most optical profilometers have difficulties in measuring three-dimensional (3D) topography of the pillar structures of transparent microfluidic devices. Existing commercial confocal profilometers are able to measure that kind of sample but their measurement speeds are too slow due to the need of point-by-point scanning process. In this research work, a high speed confocal 3D profilometry that combines the spinning Nipkow disk technique and chromatic confocal technique has been developed. Various height retrieval methods have been developed and compared. The vector projection technique has been developed to improve the vertical resolution of measurement. Multiple-image schemes have been proposed and developed to extend the measurement range. A prototype system has been built and tested with various samples. The measurement of 3D topography of pillar structures of transparent microfluidic devices has been demonstrated using the high speed confocal 3D profilometer. The vertical resolution of the system is about 0.05?m.