| 摘要 |
PROBLEM TO BE SOLVED: To provide a long-life iris diaphragm with accurate operation and small abrasion especially for high open/close cycles of a lamellate body. SOLUTION: The iris diaphragm for an exposure lens in semiconductor lithography includes a diagram substrate 2 rotating relatively with a ring 1 having a groove. A plurality of lamellate bodies 4 for adjusting the diaphragm opening are each mounted on the diaphragm substrate 2 and the ring 1 with the groove, and are guided by the curved track 6 arranged in the ring 1 with the groove. The diaphragm substrate 2 and the ring 1 with the groove are twisted with each other by a driving unit 11. The track 6 is separated to a curved part 6a in a mutual effective region and a feed-back curved part 6b. The diaphragm substrate 2 or the ring 1 with the groove can be rotated in a driving rotational direction previously selected by the driving unit 11, and the lamellate body 4 is guided as in reciprocation in the track 6. |
