A method of producing a security element, and/or a security document that includes a security element, includes the steps of (a) providing first gaps in a first layer of the security element and in a magnetic layer disposed below the first layer, the first gaps forming negative characters readable upon...http://www.google.fr/patents/US6454166?utm_source=gb-gplus-shareBrevet US6454166 - Security document with a security component and method for the production thereof
Security document with a security component and method for the production ...
