Quality assessment and process control are important tools in the production of high-quality products. In surface coating, it is necessary to determine essential properties of the applied coatings. This includes the layer thickness and the refractive index.
The compact sensor developed at the CiS Research Institute measures the polarization-dependent reflectance of two different single-mode lasers at inclined angles of incidence. The sensor operates without moving components, features low maintenance and is suitable for applications in harsh environments. Up to four sample properties (layer thicknesses, refractive indices) can be determined by fitting experimental data with a transfer matrix model using Levenberg-Marquard routines.
At SENSOR+TEST 2015, the CiS Research Institute will show a first successfully tested functional demonstrator in addition to applied technology modules for non-polarizing and polarizing beam splitters, VCSEL-based illumination components and 4-quadrant photodiodes. This is expected to shrink to the size of a matchbox by mid-2015.
Target applications of the development are the monitoring/control of thin-film coatings or of growth processes, e.g. in glass finishing or in semiconductor processing.
The research and development work is funded by the German Federal Ministry of Economics and Technology (Funding code: MF130021).
Project presentation at:
SENSOR+TEST, May 19-21, 2015, Nuremberg, Hall 12 Booth 132