Device, method, and system for recording diffractive high resolution text, pictorial, and/or other graphical information is provided which is particularly suited to recording information that would be difficult to reproduce by typical counterfeiting methods. The information recorded may be used to authenticate...http://www.google.com.tw/patents/US6222650?utm_source=gb-gplus-share專利 US6222650 - Holographic authentication element and document having holographic authentication element formed thereon
