Luminescent compound for marking and identification of marking of document by means of this compound

FIELD: estimation of authenticity of documents, excise brands, bank-notes and securities.

SUBSTANCE: proposed compound is prepared by mixing gadolinium oxysulfide activated by terbium and yttrium oxysulfide activated by ytterbium and erbium. Size of crystal particles of said luminophores does not exceed 1.5 mcm. Compound thus prepared is introduced into printing ink and is applied on surface to be marked by letterpress printing method in form of mark which is invisible at common lighting. Mark is visualized by infra-red light source and/or ultraviolet radiation thus causing its green glow. Document is subjected to identification for estimation of its authenticity of falsification. Marking retains preset properties for extended period of time at high temperatures, bright light and high moisture content.

EFFECT: enhanced efficiency of protection against falsification.

4 cl, 3 ex

 

The invention relates to the protection of valuable material objects from forgery, theft by covert recording identification data, and more particularly the invention relates to a luminescent crystalline composition for marking and method of identification marking of the document using fluorescent crystalline composition for marking.

The invention will find application in determining the authenticity of documents, excise stamps, banknotes, securities and products.

There is a method of covert recording identification data, comprising applying to the surface a layer of a solution containing a phosphor, a binder and an organic solvent, drying of the specified layer to evaporate the solvent and form a film which is then treated with a solution B containing a phosphor other than the phosphor of the solution, a binder and an organic solvent, and then dried. The ratio of solution a and solution B is(1:10) - (10:1). As phosphors used organic compounds, which form true solutions in organic solvents. In accordance with the specified method is applied in such a way identity visualize the irradiation surface radiation in the ultraviolet region of the spectrum, for example, a mercury lamp (patent RF №2057782, MK is: CC 11/06, publ. 10.04.96).

This method allows you to have when visualizing a bright and high contrast image recorded identification data, which facilitates their verification, however, there is a significant absorption of ultraviolet radiation in thin films of organic coatings and glasses, and also the necessity of application for the visualization of the sources of high voltage.

There is a method of covert recording identification data in the form of drawings, symbols, labels, comprising coating the surface of the protected products named identity, invisible under normal light illumination is performed by the composition containing the anti-Stokes phosphor constituting the crystal structure, the lattice of which are simultaneously atoms of yttrium and/or ytterbium and/or thulium (RF patent No. 2137612, MKI: 44 F 1/12, publ. 20.09.99). Visualization and verification recorded in this way hidden identity is carried out with infrared radiation.

Formulations containing only atoms of activators (ytterbium and erbium or thulium), not lumines cent when exposed to radiation in the infrared region of the spectrum. The composition of Y2About2S:Yb, Er for a long time used in printing and may not be a reliable protection products from fakes.

The specified technical solution not both, which ensures stability of the recorded latent identification data, and the brightness of their luminescence imaging, which reduces the reliability of the verification of identity. In addition, these anti-Stokes phosphors are characterized by high hardness and a coarse grain structure (grain size of 6 μm), and therefore the above method cannot be used with most types of printing used in the printing industry, including in the flexographic printing method, when applied to the surface of the protected products mentioned identification data.

As a prototype we have chosen luminescent crystalline composition for marking and method of identification marking of a document, described in French patent No. 2554122, MKI: C 11/77, publ. 03.05.1985. The composition contains as an anti-Stokes phosphor crystalline fluorides or oxychoride rare earth element activated by erbium or holmium, and as phosphors excited in the ultraviolet region of the spectrum, crystalline oxysulfide rare earth elements, for example, oxysulfide gadolinium activated with terbium or europium or samarium.

This known method of identification marking of a document, which comprises applying, for example, by a method of printing a print document surface marking performed by the above-mentioned composition is m, invisible when excited by radiation in the visible spectrum, subsequent visualization marking by illuminating the surface of the document the source of infrared and/or ultraviolet radiation and the fluorescence labeling. The appearance of luminescence and its characteristics allow the identification of the document and serve as passive protection of the document against forgery.

However, in the specified fluorescent composition based on crystalline fluorides of rare earth elements and oxyhalogenation rare earth elements, the size of crystalline particles reaches 5-10 μm, which is not applicable in most types of printing used in the printing industry, in addition, the phosphors on the basis of oxyhalogenation of rare earth elements during storage change their characteristics. While marking executed in such a structure, it is relatively easy to visualize using the available funds, which reduces the effectiveness of the passive protection of the document against forgery.

The basis for the claimed of the invention is to create such a fluorescent composition for marking and based on this method of identification marking of the document that would ensure the efficiency and stability during passive protection of the document against forgery.

This problem is solved by the creation of fluorescent m is cocrystalline composition for marking, includes oxysulfide gadolinium activated with terbium, and excited by infrared and ultraviolet radiation, which according to the invention additionally contains oxysulfide yttrium, activated with ytterbium and erbium, has a size of crystalline particles is not more than 1.5 μm, it is reasonable to oxisulfide gadolinium activated with terbium, and oxysulfide yttrium, activated with ytterbium and erbium, contained in a ratio of from 2:1 to 1:2, respectively.

This problem can be solved by implementation of the method of identification marking of a document, comprising coating the surface of the document is invisible under normal lighting marking performed luminescently crystalline composition, comprising oxysulfide gadolinium activated with terbium, subsequent visualization by illuminating the surface of the document the source of infrared and/or ultraviolet radiation, registration glow and the identification of the document, which, according to the invention as a luminescent composition using fluorescent composition, optionally containing oxysulfide yttrium, activated with ytterbium and erbium, and with the size of the crystalline particles is not more than 1.5 μm. This is useful to oxisulfide gadolinium activated with terbium, and oxysulfide yttrium, Akti is a new ytterbium and erbium, used in a ratio of from 2:1 to 1:2, respectively.

Due to the claimed invention achieved stability in time of the characteristics of the fluorescent composition for marking performed by all types of application used in the printing industry, and visualization of marks is as under excitation by ultraviolet radiation and excitation of infrared radiation that ensures the effectiveness of passive protection of the document against forgery and promotes the reliability of document protection, including securities, banknotes from fraud by reliable establish their authenticity.

Other objectives and advantages of the invention will become apparent from the subsequent detailed description of the luminescent crystalline composition for marking, method of identification marking of the document and examples of implementation of this method.

The inventive fluorescent composition for marking includes the crystalline oxysulfide gadolinium activated with terbium, and, according to the invention, the crystalline oxysulfide yttrium, activated with ytterbium and erbium.

In the structure proposed in the present invention, gadolinium and yttrium are elements of the basic substance, ytterbium - sensitizer, he absorbs infrared energy (hereinafter IR) radiation and eredet its activator atoms, the terbium and erbium - are, respectively, activators, they perceive the energy of infrared radiation and become excited and then emit a visible glow.

The inventive fluorescent composition has a green glow when excited by radiation in the infrared and ultraviolet areas of the spectrum when λ less than 280 nm.

The ratio of the number of oxysulfide gadolinium activated with terbium, and the number of oxysulfide yttrium activated with ytterbium and erbium, in the inventive luminescent composition is determined by the necessity of application of oxysulfide yttrium activated with ytterbium and erbium, with high intensity glow to maintain the intensity of the band erbium in the emission spectrum of a fluorescent composition with infrared excitation on the same level as that achieved when using only oxysulfide yttrium activated with ytterbium and erbium.

According to the invention it is desirable for oxysulfide gadolinium activated with terbium, and oxysulfide yttrium, activated with ytterbium and erbium, contained in fluorescent composition for marking in the ratio from about 2:1 to about 1:2, respectively.

In the inventive fluorescent composition for marking the crystalline oxysulfide gadolinium activated with terbium, has an average crystal size is s about 1.1 μm, and the crystalline oxysulfide yttrium, activated with ytterbium and erbium has a crystal size of about 1.5 μm, which opens the possibility to apply any type of printing process to perform on the document hidden marking the inventive luminescent composition.

In addition, the inventive luminescent composition during long-term storage practically does not change its characteristics.

The inventive method of identification marking of documents such as identity cards, banking, securities, works of art involves performing on document hidden, that is invisible under normal lighting marking in the form of, for example, drawings, symbols, labels.

In accordance with the invention, the marking is performed luminescent material on the basis of two phosphors: Gd2O2S:Tb - oxysulfide gadolinium activated with terbium, and Y2O2S:Yb, Er - oxysulfide yttrium activated with ytterbium and erbium. According to the invention, it is useful to oxisulfide gadolinium activated with terbium, and oxysulfide yttrium, activated with ytterbium and erbium, used in a ratio from about 2:1 to about 1:2, respectively.

Marking is performed using a composition on the basis of these two phosphors, invisible under normal light light and appears as bright the green fluorescence when excited by radiation in the infrared, and ultraviolet areas of the spectrum.

Studies have shown that the degree of document security from tampering when the marking is performed by the structure on the basis of these two phosphors increases only if the transition in addition to the anti-Stokes phosphor to the second phosphor excited by ultraviolet radiation, will be barely noticeable. This is only possible when adding to the anti-Stokes phosphor with high efficiency a significant amount of phosphor excited by ultraviolet radiation in the zone “C” (λmax=254 nm).

Thanks to the invention achieved the efficiency and stability during passive protection of the document against forgery.

The claimed composition with its practical application in the process of marking, for example, by the method of commercial printing, introduced into the paint, you can use varnish, glue for labeling other method.

The ratio of mixture of two phosphors Gd2O2S:Tb and Y2O2S:Yb, Er: binder choose to provide specific viscosity of the solution.

An effective amount of two phosphors: Gd2O2S:Tb and Y2O2S:Yb, Er in the binder may range from 5 wt.% and above, however, too high a content of a mixture of two phosphors makes the left is too expensive because of the high cost of phosphors.

The marking may be accomplished using any acceptance by printing, by use of a stamp, brush. It should be noted that the marking is possible to carry out printing by, since the average size of the crystals of the phosphor Gd2O2S:Tb is, as shown by studies of 1.1 μm, and the average size of the crystals of the phosphor Y2O2S:Yb, Er is, as shown by studies of 1.3 μm, which eliminates damage to the printing rollers printing presses.

Oxysulfides the phosphor, which is oxysulfide gadolinium activated with terbium, and oxysulfide yttrium, activated with ytterbium and erbium, has high lighting performance. Due to this, in all cases, labeling saves the specified properties for a long time - more than ten years of use in different operating conditions, simulating natural conditions at high and low temperatures, bright light and high humidity.

Visualization of the marking composition made on the basis of two phosphors: Gd2O2S:Tb and Y2O2S:Yb,Er, perform when illuminated surface of the document by the radiation wavelength is in the infrared region of the spectrum or the ultraviolet region of the spectrum, including in the area of Corot the e 280 nm, this causes bright green glow marking.

Visualization marks by registering its green fluorescence allows to identify the document and to make a conclusion about its authenticity or forgery.

Example 1.

Mix in vibromaster 360 grams of oxysulfide gadolinium-activated terbium, having an average crystal size of 1.1 μm, and 180 grams of oxysulfide yttrium activated with ytterbium and erbium, having an average crystal size of 1.3 μm. The resulting composition having a crystalline particles is not more than 1.5 μm, is introduced into the printing ink and is applied with a printing method of printing on a surface of an excise stamp in the form of marks, invisible under normal lighting.

Visualize marked by illuminating the surface of an excise stamp radiation in the ultraviolet region of the spectrum (λ=254 nm) or by the emission of the led (λ=960 nm), causing it to glow green.

Visualization marking allows the identification of documentary stamps and to make a reliable conclusion about its authenticity.

Example 2

Mix in vibromaster 180 gram oxysulfide gadolinium-activated terbium, having an average crystal size of 1.1 μm, and 240 grams of oxysulfide yttrium activated with ytterbium and erbium, having an average crystal size of 1.3 μm. The resulting composition, and Audi crystalline particles is not more than 1.5 μm, enter in the printing ink, and causing the printing method of printing on a surface of an excise stamp in the form of marks, invisible under normal lighting.

Visualize marked by illuminating the surface of an excise stamp radiation in the ultraviolet region of the spectrum (λ=254 nm) or by the emission of the led (λ=960 nm), causing it to glow green.

Visualization marking allows the identification of documentary stamps and to make a reliable conclusion about its authenticity.

Example 3

Mix in vibromaster 180 gram oxysulfide gadolinium-activated terbium, having an average crystal size of 1.1 μm, and 360 grams of oxysulfide yttrium activated with ytterbium and erbium, having an average crystal size of 1.3 μm. The resulting composition having a crystalline particles is not more than 1.5 μm, is introduced into the printing ink and is applied with a printing method of printing on a surface of an excise stamp in the form of marks, invisible under normal lighting.

Visualize marked by illuminating the surface of an excise stamp radiation in the ultraviolet region of the spectrum (λ=254 nm) or by the emission of the led (λ=960 nm), causing it to glow green.

Visualization marking allows the identification of documentary stamps and to make a reliable conclusion about its authenticity.

1. Lumines entry crystalline composition for marking, includes oxysulfide gadolinium activated with terbium, and excited by infrared and ultraviolet radiation, characterized in that it additionally contains oxysulfide yttrium, activated with ytterbium and erbium, and has a size of crystalline particles is not more than 1.5 μm.

2. Fluorescent crystalline composition for marking according to claim 1, characterized in that oxysulfide gadolinium activated with terbium, and oxysulfide yttrium, activated with ytterbium and erbium, are contained in a ratio of from 2:1 to 1:2, respectively.

3. The method of identification marking of a document, comprising coating the surface of the document is invisible under normal lighting marking performed fluorescent crystalline composition, comprising oxysulfide gadolinium activated with terbium, subsequent visualization by illuminating the surface of the document the source of infrared and/or ultraviolet radiation, registration glow and the identification of the document, characterized in that the luminescent composition using fluorescent composition having the size of the crystalline particles is not more than 1.5 μm, optionally containing oxysulfide yttrium, activated with ytterbium and erbium.

4. The method according to claim 4, characterized in that oxysulfide gadolinium activated with terbium, and oxysulfide Tria, activated with ytterbium and erbium, used in a ratio of from 2:1 to 1:2, respectively.



 

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FIELD: estimation of authenticity of documents, excise brands, bank-notes and securities.

SUBSTANCE: proposed compound is prepared by mixing gadolinium oxysulfide activated by terbium and yttrium oxysulfide activated by ytterbium and erbium. Size of crystal particles of said luminophores does not exceed 1.5 mcm. Compound thus prepared is introduced into printing ink and is applied on surface to be marked by letterpress printing method in form of mark which is invisible at common lighting. Mark is visualized by infra-red light source and/or ultraviolet radiation thus causing its green glow. Document is subjected to identification for estimation of its authenticity of falsification. Marking retains preset properties for extended period of time at high temperatures, bright light and high moisture content.

EFFECT: enhanced efficiency of protection against falsification.

4 cl, 3 ex

FIELD: possible use for manufacturing indication devices.

SUBSTANCE: multi-color cathode luminescence screen contains a color based on two mechanically mixed electron-exited phosphors, one of which is the sub-linear red-emitting one based on oxy-sulfide of yttrium-europium and is described by stoichiometric formula Y2-x-yEuxCayO2S1-z, where x=0,01-0,1; y=0,001-0,05; z=0,5y, and second one - super-linear green-emitting composed of ZnS·CdSCu,Al,Co. The screen emits radiation in orange-red spectrum range when irradiated with electron beam at integral density of current j=0,2 mcA/cm2, ensuring resolution I>5 lin/mm. With growth of current density up to j>1mcA/cm2 the color of radiation shifts to yellow-green spectrum range. Cathode-ray device for displaying multi-color information contains within a vacuumized glass case the multi-color cathode luminescence screen located on its internal frontal surface, electron-optical system consisting of thermal emitter, modulating, focusing and accelerating electrodes. Cathode luminescence screen contacts the solid aluminum cover of accelerating electrode. Modulator electrode is made in form of a metallic diaphragm with axis-symmetric aperture. Invention makes it possible to change the color of radiation from red to green.

EFFECT: increased resolution.

2 cl, 2 tbl

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