At the light emission surface of a light-guiding plate, first and second grooves and second grooves are formed. Each of the first grooves has a pair of slope parts, and each slope part has an easy slope and a steep slope. The second grooves intersect the first grooves at predetermined angles. Each of...http://www.google.co.uk/patents/US7360939?utm_source=gb-gplus-sharePatent US7360939 - Surface emitting device, backside illumination device, and liquid crystal display device
