A reflecting plate material, comprises a urethane plate having first and second opposite major surfaces. The first major surface is planar and the second major surface is formed with a plurality of cube corners each one of which has a plurality of facets. The facets are clouded to provide degraded retro-reflecting...http://www.google.ca/patents/US7425075?utm_source=gb-gplus-sharePatent US7425075 - Optical reflecting material
