Patent ID: 9684243
Date: 2017-06-20
CPC Classifications: G03F

Claim:
1. Projection exposure apparatus for microlithography defining a beam path along which propagates electromagnetic radiation with which the projection exposure apparatus is operated, and comprising: at least one filter arranged in the beam path, at least one sensor device configured to monitor the at least one filter, at least one blocking element configured to move between a standby position and a barrier position, wherein the movement of the blocking element is effected in accordance with a signal of the sensor device, and wherein in the barrier position a region of the projection exposure apparatus is blocked off relative to the at least one filter such that parts of a destroyed or damaged one of the at least one filter cannot pass into the blocked-off region of the projection exposure apparatus, at least one of an open-loop control unit and a closed-loop control unit, and an actuator configured to actuate the blocking element, wherein the actuator comprises an energy store configured to store actuating energy.