A rear projection or translucent screen consisting of a circular Fresnel lens consisting of a plurality of concentrically circular lens elements and a lenticular lens having a plurality of corrugated parallel convex lens elements. Parallel projections or ridges are formed on the surface opposite to the...http://www.google.es/patents/US4509823?utm_source=gb-gplus-sharePatente US4509823 - Rear projection screen
