Patent ID: 8345224

Claim:
A method, comprising: a) providing a micromirror array in an illumination system of a microlithographic projection exposure apparatus, the micromirror array comprising a micromirror which is tiltable through a respective tilt angle about two tilt axes, the micromirror being assigned three actuators, each of the three actuators being capable of being driven by control signals to tilt the micromirror about the two tilt axes; b) specifying two control variables, each of the two control variables being assigned to one tilt axis, and both of the two control variables being assigned to unperturbed tilt angles; c) for any desired combinations of the two control variables, as a function of the two control variables, selecting one of the three actuators whose control signal is set to a constant value; d) determining the control signals so that, when the control signals are applied to the other two actuators, the micromirror adopts the unperturbed tilt angles as a function of the two control variables; and e) applying the control signals to the actuators.