COMPOSITE LUMINESCENT MATERIAL, METHOD OF PRODUCTION THEREOF (EMBODIMENTS) AND DATA MEDIUM Russian patent published in 2024 - IPC C09K11/08 C09K11/06 B42D25/36 D21H21/40 D21H21/48 G06K19/14 

FIELD: physics.

SUBSTANCE: group of inventions can be used for counterfeit protection and reliable identification of information media: banknotes, excise stamps, identification documents, museum exhibits or valuable documents. Composite luminescent material is made in the form of powder with average particle size of 0.1–50 mcm and contains luminescent components having luminescence of different spectral composition in range of 370–780 nm, intersecting or coinciding excitation spectra, wherein duration of their afterglow differs by at least 20 %. Said composite material can be made in the form of particles of an inorganic luminescent component coated with a layer of an organic luminescent component and having a core-shell structure or a layered structure. This composite material is obtained by applying an intermediate layer of nano-sized spherical silicon dioxide particles onto particles containing the first luminescent component and subsequent deposition of the remaining luminescent components from the liquid phase. In another embodiment, the composite material can be a three-dimensional xerogel structure with particles of luminescent components adsorbed on its three-dimensional surface. Such a composite material is obtained by making a hydrogel based on carboxymethyl cellulose, or silicon, or aluminium, or acrylamide, or acrylic acid and salts thereof, introduction of luminescent components and subsequent removal of liquid phase. As an organic luminescent component, said composite material can contain metal-organic complexes of Eu (III) or Tb (IV). As an inorganic luminescent component, said composite material can contain SrAl₂O₄:Eu,Dy; SrAl₁₄O₂₅:Eu,Dy; Sr₂SiO₄:Eu,Dy; ZnS:Cu,Co; Sr₂MgSi₂O₇:Eu,Dy; CaAl₂O₄:Eu,Nd; Y₂O₂S:Eu,Ti,Mg; CaS:Eu,Pr; Ca₂Si₅N₈:Eu,Tm or NaCa₂GeO₄F:Mn,Yb. One of the luminescent components can additionally have the property of photostimulated modulation of luminescence when exposed to radiation in region of 200–700 nm. Protective marking containing said composite luminescent material, are introduced into the data carrier, or applied onto its surface by a printing method in the form of graphic patterns, and/or geometric figures, and/or alphanumeric symbols, and / or personal data.

EFFECT: increased security of data carriers and provision of subsequent control of their authenticity in conditions of circulation due to visual colour-variable effect, which consists in pronounced and reproducible change in the colour of the luminescence of the material when photoexcitation is applied and removed.

14 cl, 1 tbl, 15 ex