A correction mask for an optical beam homogenizer includes a lens array. The correction mask is configured to provide a shaped initial beam profile. A subset of a plurality of optical paths between the incoming light beam and the illumination plane is at least partially blocked by the correction mask to provide a further homogenized beam profile having a further reduced light intensity variance with respect to an initial homogenized beam profile. The mask includes a plurality of submasks arranged according to a mask grid layout matching the lens grid layout of the lens array. Each one of the submasks is designed with a specific submask pattern to shape the respective subarea of the initial beam profile passing a specific one of the lenslets.