DEVICE AND METHOD FOR MOIRÉ MEASUREMENT OF AN OPTICAL TEST SPECIMEN

摘要

The invention relates to a device for Moiré measurement of an optical test specimen, comprising a grating arrangement composed of a first grating (25, 25', 35, 35'), which is positionable in the optical beam path upstream of the test specimen, and a second grating (11, 11', 11", 41, 51, 61, 71, 81, 91, 101, 111, 121, 131, 141), which is positionable in the optical beam path downstream of the test specimen, an evaluation unit having at least one detector (12, 12', 12", 22, 22', 32, 32', 42, 52, 62, 72, 82, 92, 102, 112, 122, 132, 142) for evaluating Moiré structures produced by superimposition of the two gratings in a detection plane situated in the optical beam path downstream of the second grating, and at least one aperture stop (14, 14', 14", 24, 24', 34, 34'), by which the light distribution produced after emergence of light from the second grating can be shaded regionally in such a way that only light of a subset of all field points on the second grating reaches the detection plane.