Counterfeit-proof value document and a method for verifying the authenticity thereof

Abstract

The invention relates to the protection of value documents against counterfeit and is intended for use in verifying the authenticity of protected printed products, such as all types of value documents, using an instrument. The invention has the technical result of increasing the level of protection of a value document. The value document is provided with a mark containing a fluorescent compound that exhibits both Stokes and anti-Stokes fluorescence and has the composition: Ln1-x-?.z Yb x Er ? Ce z Me I C MeIII D P 1-D ? 4+D / 2-C, where: MeI - Li or Na, MeIII- W or Mo, Ln - Y, La, Gd, 0.1 = ? = 0.9; 0.005 = y = 0.2; 0.0001 = z = 0.01; 0.001 = ? = 0.1; 0.001 = d = 0.1; or a compound that has the composition: Ln 2-?- ?-z Ybx Er? Cez O2 S, where Ln - Y, La, Gd, 0 2-x-?-z Er? CeZ O2 S; where Ln - Y, La, Gd, 0 < ? =0.2; 0.1 = ? = 0.4; 0.0001 = z = 0.005. The mark can be produced by printing, for example by offset printing. The method for verifying the authenticity of a value document with all of the above-mentioned features involves detecting a latent protective mark on a value document by measuring and subsequently analyzing the degree to which the intensity of the Stokes and anti-Stokes lines depends on the power density of the exciting radiation.

Description

technical field [0001] The invention relates to the anti-counterfeiting of valuable certificates and the instrument identification of anti-counterfeiting printed matter such as banknotes, blank paper securities, tax labels, stamps, labels and the like. Background technique [0002] The most efficient and practical way to verify the authenticity of banknotes with hidden security features is to evaluate the secondary emission of fluorescent compounds contained in security markings or in the substrate of banknotes and documents of value. This method is very effective and ensures a high level of protection due to the hidden security element and contactless authentication method. [0003] In view of the above advantages, hidden security features based on the use of various inorganic fluorescent compounds have been widely used in banknote high-speed sorting and authenticity verification. [0004] Known inorganic fluorescent compounds include rare earth based activators such as ti...

AI Technical Summary

Problems solved by technology

[0015] Since the fluorescence spectrum of the security features described in this prior art is conventional and depends only on the nature of the dopant (ion of the rare earth element REE), the information value of the spectroscopic analysis of the fluorescence or absorption of substances containing said elements Low, after initially identifying the type of REE used in the security label, a potential counterfeiter may easily guess the imitation, and as mentioned above, the imitation may have a composition that is significantly different from the real substance