Patent ID: 7911624

Claim:
A device for interferometric measurement of phase masks, comprising an interferometric measurement arrangement, comprising: a source of radiation; a diffraction grating; two imaging optics including a first imaging optics and a second imaging optics; a spatially resolving detector; and an evaluating unit; wherein radiation passing through either a coherence mask or through a pinhole is made to interfere by a diffraction grating, and further wherein a phase mask is arranged, in or near the pupil plane of the first imaging optics and wherein the phase mask can be precisely positioned in an x-y direction and by which at least two interferograms that are phase-shifted in the x-y direction relative to each other are generated by translational displacement of one of the coherence mask and the pinhole or the diffraction grating between a first position and a second position, one interferogram being generated in the first position and another interferogram being generated in the second position, and wherein the at least two interferograms are imaged on the spatially resolving detector via the second imaging optics and from which the evaluation unit determines the phase and transmission functions of the phase mask, and further wherein imaging of the interferograms onto the spatially resolving detector is effected with magnification.