PRINTED IMPORTANT DOCUMENT WITH LUMINESCENT AUTHENTICITY INDICATION Russian patent published in 2002 - IPC

FIELD: documents protected against forgery. SUBSTANCE: printed important document has at least one authenticity indication made by means of luminescent agent on base of crystal lattice alloyed by at least one rare-earth metal which absorbs radiation practically over entire visible region of spectrum; it is excitable at essential sections of visible region of spectrum and is partially transparent at least within the following wave band: from 0.8 to l.l mcm. Rare-earth metal emits radiation in wave band of from 0.8 to 1.1 mcm; crystal lattice of base has structure of pomegranate or perovskite. Ytterbium, praseodymium or neodymium may be used as rare-earth metal. Protective element has at least substrate and luminescent agent on base of crystal lattice alloyed by at least one rare-earth metal. Luminescent agent may be admixed to printing ink, paper pulp and may be present on substrate or in its material. Substrate may be made from plastic or paper in form of protective filament or from composite fibers in form of plate or label. EFFECT: high degree of protection. 22 cl, 6 dwg