Patent ID: 7884920

Claim:
A lithographic apparatus comprising: an illumination system configured to condition a radiation beam; a support constructed to support a patterning device, the patterning device being capable of imparting the radiation beam with a pattern in its cross-section to form a patterned radiation beam; a substrate table constructed to hold a substrate; a projection system configured to project the patterned radiation beam onto a target portion of the substrate; a mirror assembly to interact with the radiation beam, the mirror assembly comprising: a mirror structure being pivotable about at least one axis and comprising a reflecting surface, and an actuator to pivot the mirror structure, the actuator having a contacting surface to establish contact with a contacting part of the mirror structure, wherein the actuator is configured to move the mirror structure in a first direction by moving the contacting surface in a repeated pattern of movement of the contacting surface in the first direction at a first speed or acceleration followed by movement of the contacting surface in a second direction at a second speed or acceleration, wherein the second direction is substantially opposite to the first direction and the second speed or acceleration is greater than the first speed or acceleration.