Position measuring device, has part carrier including surface lying in proximity of focal plane of lens arrangement, such that image of impurities or residual particle on carrier surface, is delocalized over sensitive surface of detector

摘要

The device has a scanning unit scanning a material measure for determining position information. A part carrier (1) includes a surface (12) lying between the measure and a radiation sensitive surface (35) of a detector in the scanning unit. The carrier surface lies in the proximity of a focal plane of the arrangement, such that an image of impurities or residual particle on the carrier surface, is delocalized over the detector surface.