| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom system for an illumination device which does not need to exchange optical elements and is capable of adjusting the degree of coherence in a wide range. SOLUTION: A zoom system constituted in a form of a focal-length zoom lens for an illumination device of a microlithgraphic projection exposure system is disclosed. The lenses for the zoom system define an object plane (6) and an image plane (8) which is a Fourier transform of the object plane. The system is characterized by a large enlargement of the illuminated region in the image plane, wherein the enlargement factor of more than 4 can be realized. The system has only two movable lenses (31, 32). COPYRIGHT: (C)2003,JPO
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