Fast and reliable in-situ measurements of large and complex surfaces using a novel deflectometric device

In-situ measuremens of complex surfaces during the polishing process is a challenge for the production of aspheric surfaces or freeforms. We are providing a new attempt by using a scanning deflectometric device based on our recently publshed DaOS principle, which allows in-situ measurements of large optical surfaces in realistic production enviroments. The results of in-situ surface measurements after two polishing steps of a large glass substrate (320mm in diameter) in alever-polishing machine (NLP-500 from Stock Konstruktion) are shown and critically compared with interferometric measurements on a SSI-A Interferometer. In this presentation, the technical setup consisting of a highly precise scanning penta prism device and a Vignetting Field Stop Sensor is explained.