Iris especially for exposure objective in semiconductor lithography equipment, has leaves which can be moved approximately linearly to the optical axis of the iris

摘要

An iris has several leaves carried by guide elements, and are movable by drive device for adjusting the shutter opening. The guide elements (slot (5) and guide pins (4)) are designed so that the leaves (2) are movable, at least approximately, linearly to the radial direction of the optical axis of the iris (1) and each of the leaves (2) can be individually driven.