A temporaty badge fabrication system is provided. The system comprises a badge for attachment to a wearer having at least one surface coated with an ambient light sensitive coating thereon which when exposed to ambient light conditions for a specified period of time changes to a specified color. An apparatus...http://www.google.es/patents/US4779120?utm_source=gb-gplus-sharePatente US4779120 - Light sensitive validating identification badge system
Light sensitive validating identification badge system
