Test arrangement for the contactless ascertainment of flows in non-structured surfaces

摘要

To determine defects (D) in non-structured areas (F), the area (F) to be examined is scanned with a scanning light beam (As), the light scattered and diffracted by a defect (d) on the light-sensitive area of an optoelectronic receiver ( E) is collected. In order to be able to detect defects (D) in the submicrometer range, an aperture (B) for reducing the amount of scattered light is attached in the beam path of the scanning light beam (As), in which at least two aperture edges, preferably a plurality of aperture edges, are arranged one behind the other in such a way that they only capture the shadow area of the previous diaphragm edge. Such a test arrangement is e.g. B. used in the testing of not yet structured masks.