Patent ID: 8345219
Filing Date: 2013-01-01
Classification: G03F

Abstract:
1. A method for setting an illumination optical unit comprising a plurality of optical surfaces for guiding and shaping a beam of illumination light, wherein an illumination parameter to be set is predefined across an object field to be imaged into an image field, the method comprising: determining at least one actual value of the intensity-weighted illumination parameter of the illumination optical unit at a plurality of field points and for a plurality of illumination angles; determining the influence of a deformation of at least one of the optical surfaces of the illumination optical unit on the at least one illumination parameter; predefining a desired value of the illumination parameter; determining a desired form of the at least one optical surface whose deformation influence has been determined, in such a way that the actual value of the illumination parameter corresponds to the desired value of the illumination parameter within predefined limits; and deforming the optical surface with the aid of at least one actuator which exerts a mechanical stress on the optical surface in such a way that an actual form of the optical surface corresponds to the desired form.