A cup-shaped elastic member 2 forces push button 1 upwardly that has indication part 1A formed thereon. Light transmitting electrode layer 15B, light-emitting layer 15C, and back electrode layer 15E are sequentially formed on light transmitting sheet 15A to form EL element 15, and the EL element is disposed...http://www.google.se/patents/US6686549?utm_source=gb-gplus-sharePatent US6686549 - Illuminated keyboard switch
