A pattern, is imaged by means of a programmable mask, on a substrate that has a photosensitive layer, illumination spots being produced on the mask by means of an illumination unit and individual pixels being produced, via an optical unit, forming a grid of pixels on the substrate corresponding to the pattern. Structure edges that are to be reproduced on the substrate are positioned optimally. To this end at least two exposure processes for the photosensitive layer are performed, the illumination spots or exposure points of which are offset from one another. Thereby, spaces in the grid of pixels of the first exposure process, which spaces are proportionate to the number of exposure processes to be effected, are filled with pixels by the subsequent exposure processes.