INORGANIC LUMINESCENT COMPOUND, MARKING USING INORGANIC LUMINESCENT COMPOUND AND INFORMATION MEDIUM USING INORGANIC LUMINESCENT COMPOUND Russian patent published in 2020 - IPC C09K11/08 B42D25/36 

FIELD: chemistry.

SUBSTANCE: invention relates to inorganic luminescent compounds based on rare-earth metal ions having excitation, photostimulation and luminescence spectra primarily in the visible and near infrared spectral ranges, and which can be used as authenticity features for valuable documents when used in paper or in printing inks. Inorganic compound based on elements of group III of the periodic table, having luminescence of a given spectral composition in the wavelength range of 700–3000 nm under the effect of exciting radiation with wavelength of 700–1600 nm, and having optical luminescence quenching property under action of stimulating radiation with wavelength of 200–700 nm, characterized by that its composition is a collection of at least two solid solutions of type 1 crystalline substances based on rare-earth elements.

EFFECT: technical result achieved when implementing the developed invention consists in expanding the range of inorganic luminescent substances, having luminescence in the spectral range of 700–3000 nm under the effect of exciting radiation lying in the spectral range of 700–1600 nm, and additionally having the property of changing luminescence intensity without changing its spectral composition when exposed to stimulating radiation lying in the spectral range of 200–700 nm.

8 cl, 3 tbl