High-security transparent overlays: a new method for selective demetallization of fully registered embossed holograms

摘要

Abstract: Optically variable devices (OVDs) are relatively new security features which are currently finding widespread application on a variety of security documents as a means of protection against counterfeiting. The OVD is in general a complex optical recording and the commonest form seen today is based on the presence of optically diffracting features, which are manufactured using embossing technology. This presentation deals with one particular type of security product - a transparent or semi-transparent document overlay which may include an OVD combined both with UV-fluorescent or other special links, and may also include individualized information applied by laser-engraving technology. The main applications lie in the field of paper-based security documents such as passports, visas, driver's licenses and ID- cards. !0