An optical disc has a security feature in the form of an RFID tag that communicates with a voltage controlled optical modifier layer in the optical disc. In the presence of an interrogation signal, the RFID tag allows the optical disc to be used normally by outputting a voltage to the optical modifier...http://www.google.com/patents/US7571115?utm_source=gb-gplus-sharePatent US7571115 - RFID security device for optical disc
