US Patent 7333177 Lithographic apparatus and device manufacturing method

A lithographic method and apparatus used to pattern an object. An illumination system supplies a beam of radiation. An array of individually controllable elements patterns the beam. The patterned beam is projected by a projection system on to a substrate supported on a substrate table. Individual elements of the array are periodically addressed to load an image frame on to the array appropriate to the pattern to be imparted to the beam at any given instant in time taking into account the image to be projected onto the substrate. In any given frame loading operation, only those individual controllable elements that must change state are addressed to reduce the amount of data required to be transferred during the frame loading operation.