| 摘要 |
PROBLEM TO BE SOLVED: To provide an equipment for measuring the aberration of a reflective diffraction element comprising a wave-surface measuring system having an electromagnetic irradiating source. SOLUTION: An imaging system directs electromagnetic radiation to a body surface, and evenly illuminates it. A first grating is disposed inside the body surface, and an illuminating light to the surface of an entrance pupil is adjusted in a projection optical system. The projection optical system projects the image of the first grating to a focal surface. A second grating is disposed on the focal surface to receive the refractive image of an irradiating light to form a Shearing interferometer. A CCD detector receives the image of the first grating through the projection optical system and the second grating, and generates an interference fringe when some aberration exists in the projection optical system. The phase shift of the interference fringe is read out by stepping the first grating in the lateral direction, and detecting each of frames using the CCD detector. The first grating includes a plurality of reflecting lines comprising a plurality of reflecting dots. COPYRIGHT: (C)2009,JPO&INPIT
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