A projection-type liquid-crystal display in which a Fresnel lens in placed on the exit side of the liquid crystal panel to focus the image toward a projection lens. Preferably, the Fresnel lens has a non-symmetric pattern so as to efficiently gather light propagating through the display panel at an oblique...http://www.google.es/patents/US4936657?utm_source=gb-gplus-sharePatente US4936657 - Projection type liquid-crystal video display device using a fresnel lens
Projection type liquid-crystal video display device using a fresnel lens
