| 摘要 |
A projection exposure system, in particular for microlithography, serves to generate an image of an object disposed in an object plane in an image plane. For this purpose, use is made of a light source emitting projection light, illumination optics disposed in the beam path between the light source and the object plane and projection optics disposed in the beam path between the object plane and the image plane. Disposed in the vicinity of a field plane of the illumination optics is at least one optical element that changes the angular illumination distribution of the projection light passing through. The change, impressed by the optical element, in the angular illumination distribution is non-rotationally symmetrical with respect to the optical axis. The optical element can be disposed in various angular positions around an axis perpendicular to the field plane. Such an optical element makes it possible to modify the symmetry of the angular illumination distribution flexibly.
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