The invention relates to a projection system, comprising a radiation source, an illumination system operable to illuminate a structured mask, and a projection objective for projecting an image of the mask structure onto a light-sensitive substrate, wherein said projection system comprises an optical...http://www.google.es/patents/US20100045957?utm_source=gb-gplus-sharePatente US20100045957 - POLARIZATION-MODULATING OPTICAL ELEMENT
