VALUABLE DOCUMENT Russian patent published in 2003 - IPC

FIELD: document counterfeit protection. SUBSTANCE: printed document has at least one autheticity mark produced with added luminescent substance on the basis of substrate crystal lattice alloyed with at least two rare-earth metals that absorbs radiation and is excitable mainly in visible spectrum bandwidth area and transparent in at least several individual infrared spectrum bandwidth areas. The rare-earth metals are thulium and holmium and the luminescent substance is available in the bulk of valuable document material or in the layer covering the valuable document in such permissible limit concentration that does not deteriorate properties of this valuable document or layer. Protection mark has substrate and luminescent substance on the basis of substrate crystal lattice alloyed with at least two rare-earth metals. The luminescent substance is available in the bulk of valuable document material or in the layer covering the valuable document in such permissible limit concentration that does not deteriorate properties of this protection mark or layer. EFFECT: high degree of protection reliability. 22 cl 3 dwg