A beam homogenizer that minimizes undesired intensity variations at the output plane caused by sharp breaks between facets in previous embodiments. The homogenizer includes a hologram made up of irregularly patterned diffractive fringes. An input beam illuminates at least part of the hologram. The hologram...http://www.google.com.au/patents/US6970292?utm_source=gb-gplus-sharePatent US6970292 - Beam shaping element for use in a lithographic system
