A static diffracting grating display system provides a fixed image representing high digital content information. A plurality of physical diffracting features are fixed into the surface of a substrate. The diffracting features are positioned and oriented to selectively diffract or reflect a first incident...http://www.google.com.au/patents/US6101036?utm_source=gb-gplus-sharePatent US6101036 - Embossed diffraction grating alone and in combination with changeable image display
