CARTA DI RICONOSCIMENTO A PIU STRATI

摘要

A multi-ply identification card for storage of machine-readable information includes optical markings disposed between protective layers. At least one of the protective layers can be penetrated by infrared light, and both are opaque to light of lesser wavelengths. The optical markings have a fine structure with at least 300 lines per mm and the protective layers are so connected to the optical markings that the markings are destroyed if one of the protective layers is removed.