Anti-tampering element for document

摘要

Document anti-fraud device in which at least two motifs are printed on a support (3) surface. One of the motifs has an ink that reacts to a given light wavelength and emits a given color, the other has an ink that emits the same color as the first motif when exposed to the same wavelength, but also emits a second color when exposed to a second light wavelength. An Independent claim is made for an optical reader with a system (4) for emitting UV light of two wavelength bands and an optical detector (5) for detecting the light emitted by the fluorescent dye pigments. An Independent claim is made for a document authentication method in which documents are passed beneath reference light sources and then the emitted fluorescent light detected under ultra-violet light to check document authenticity.