A display screen of a projection system embodying a cathode ray tube, liquid crystal light valve, laser or the like is formed of a plastic sheet (22, 22a) that has embedded therein a number of microsphere diffuser particles (24, 24a) initially having a spherical shape and distributed in a uniformly isotropic...http://www.google.com.au/patents/US5473454?utm_source=gb-gplus-sharePatent US5473454 - Elliptical diffuser
