Deflectometric Acquisition of Large Optical Surfaces DaOS

Abstract

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.

Numerical and Experimental Modal Analysis Applied to an Optical Test System Designed for the Form Measurements of Metre‐Scale Optics

“…is instrument provided a ∼500 um spatial resolution of the measured topography. Other methods such as de ectometry [4,5], Hartman test [6], or Sagnac interferometer [7] are available for large surfaces but they do not provide the same bene ts. Whatever, all the optical measurement techniques are a ected by both thermal and structural performances of the test system.…”