| 摘要 |
An iris diaphragm, in particular for an exposure lens in semiconductor lithography, is provided with a diaphragm base (2) and a grooved ring (1) which can be rotated relative to one another, having a multiplicity of leaves (4) which in each case are mounted in the diaphragm base (2) and in the grooved ring (1) and are guided by curved tracks (6), arranged in the grooved ring (1), for the purpose of adjusting the diaphragm aperture. A drive device (11) serves the purpose of twisting the diaphragm base (2) and grooved ring (1) relative to one another. The curved tracks are designed as circumferential tracks (6) in the grooved ring (1). The circumferential track (6) is split up into alternating useful-region curves (6a) and return curves (6b). The diaphragm base (2) or the grooved ring (1) can be rotated in a preselected rotary drive direction by a drive device (11), the leaves (4) being guided in a circulating fashion in the circumferential track (6).
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