The vignetting field stop procedure uses a deflectometric approach to acquire big optical surfaces (DaOS) and it offers the possibility to measure nearly any shape or form by using a scanning routine. The basic physical measurement principle in DaOS is the vignettation of a quasi-parallel light beam emitted by an expanded light source in auto-collimation arrangement with a reflecting element. Thereby, nearly any curvature of the specimen is measurable. Due to the fact that even sign changes in the curvature can be detected, aspheres and freeform surfaces of any size can be evaluated. Actual results of test measurements with calculated absolute deviation with larger lateral dimensions on flat and spherical specimen with diameter of 300 mm are examined. These measurements are compared critically to reference results which are recorded by interferometry and the DFR method.
Ein neues Verfahren mit vignettierender Feldblendenauswertung nutzt die Vignettierung zur Winkelmessung und umgeht die Problematik der Messbereichseinschränkung beim klassischen Autokollimator. Messprinzip, Messbereich sowie die mathematischen Grundlagen mit numerischer Simulation werden vorgestellt. Die Einflüsse geometrischer und photometrischer Effekte auf die Intensitätsverteilung sowie auf die dadurch verursachte Linearitätsabweichung werden theoretisch hergeleitet und mit experimentellen Werten verglichen.
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