PROTECTIVE SIGN Russian patent published in 2015 - IPC C09K11/79 C09K11/67 G07D7/12 

FIELD: printing.

SUBSTANCE: invention relates to a protective sign for protection of important documents, first of all for providing of their authenticity. The protective sign includes luminescent pigment which has the inorganic crystal lattice alloyed by the phosphor selected from rare-earth ions of erbium, holmium, neodymium, thulium, ytterbium and which for the radiation of luminescent light is implemented with a possibility of optical excitement. Luminescent light of the luminescent pigment has a luminescent spectrum with the first luminescent peak and the second luminescent peak the peak intensities of which depend respectively on the molar share x of phosphor in the luminescent pigment. In the luminescent pigment the crystal lattice, phosphor and the molar share x of phosphor are selected in such a way that already small increase or decrease of the molar share x of phosphor causes significant relative change of peak intensities I_A and I_B.

EFFECT: fraud-proof of luminescent pigment according to the invention is improved.

14 cl, 3 dwg, 2 tbl, 2 ex