A light system comprising a light source adapted to illuminate an area and at least two refracting substantially transparent and coextensive films juxtaposed with one another and interposed between the source and the area, the films having mutually confronting patterns of refracting rises formed on respective...http://www.google.fr/patents/US5247390?utm_source=gb-gplus-shareBrevet US5247390 - Lightweight low-loss refractive light diffusion system
Lightweight low-loss refractive light diffusion system
