New approaches in depth-scanning optical metrology

摘要

Depth-scanning is an established technique in macroscopic and microscopic 3-D metrology. Representative in this context are the confocal technique and the white-light interferometry. A new fast depth-scanning technique has been applied to a confocal point sensor to be used in a laser-welding application for in-process measurement. The depth measurement range can be extended to about +/-1 mm at about 1500 measurement cycles per second. The possibilities and the potential of these techniques are described. Another principle of depth-scanning is the chromatic confocal technique. In connection with a new approach, an innovative confocal setup enables the parallelization of the complete depth-scan for the complete measurement of a line cut of moved objects. In the macroscopic scale, the new measurement techniques of depth-scanning fringe projection (DSFP) was introduced recently. In the microscopic scale, it has been implemented successfully in a stereo microscope.