| 摘要 |
An optical system of a microlithographic exposure apparatus comprises at least one optical element (L 1 to L 16, 15, 16, 24 ) having a locally varying birefringence direction distribution that is caused by stress-induced birefringence and is at least substantially rotationally symmetrical. At least one birefringent correcting element (K 1 , K 2 ; K') is made of a crystal having a location independent birefringence direction distribution that is at least substantially rotationally symmetrical. The crystal has a crystal lattice orientation that is oriented such that its birefringence direction distribution is at least substantially perpendicular to the locally varying birefringence direction distribution of the at least one optical element (L 1 to L 16, 15, 16, 24 ).
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