Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
  • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
  • C09K11/77—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals
  • C09K11/7766—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals containing two or more rare earth metals
  • C09K11/7776—Vanadates; Chromates; Molybdates; Tungstates
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
  • B41M3/00—Printing processes to produce particular kinds of printed work, e.g. patterns
  • B41M3/14—Security printing
  • B41M3/144—Security printing using fluorescent, luminescent or iridescent effects
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
  • B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
  • B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
  • B42D25/20—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof characterised by a particular use or purpose
  • B42D25/29—Securities; Bank notes
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
  • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
  • C09K11/77—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals
  • C09K11/7766—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals containing two or more rare earth metals
  • C09K11/7774—Aluminates
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
  • D21H21/14—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
  • D21H21/40—Agents facilitating proof of genuineness or preventing fraudulent alteration, e.g. for security paper
  • D21H21/44—Latent security elements, i.e. detectable or becoming apparent only by use of special verification or tampering devices or methods
  • D21H21/48—Elements suited for physical verification, e.g. by irradiation
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S283/00—Printed matter
  • Y10S283/901—Concealed data
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S283/00—Printed matter
  • Y10S283/904—Credit card
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/22—Nonparticulate element embedded or inlaid in substrate and visible
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/24—Structurally defined web or sheet [e.g., overall dimension, etc.]
  • Y10T428/24802—Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.]

Definitions

• the invention relates to a printed document of value with at least one authenticity feature in the form of a luminescent substance based on host lattice doped with at least one rare earth metal.
• the rare earth metals can be incorporated together with other substances in host grids in such a way that the excitation and / or emission spectrum of the rare earth metal is influenced in a characteristic manner.
• suitable absorbent substances for example, part of the excitation and / or emission areas of the rare earth metal can be suppressed.
• the influence can, however, also consist in a "deformation", e.g. by damping certain areas of the excitation or emission spectra.
• the object of the invention is to create a document of value with an authenticity marking in the form of luminescent substances which are even more difficult to detect than the prior art and thus offer increased protection against counterfeiting.
• the solution to this problem results from the independent claims. Further training is the subject of the subclaims.
• the emission lines of the rare earth metals lying in the IR spectral range are used. Emission lines which are in the near IR range are preferably used, since they can still be detected with inexpensive sensors and, because of the favorable signal / noise ratio, incorrect measurements can be avoided relatively easily. Usually, commercial silicon (Si) or germanium (Ge) detectors are used for this. The farther the emission lines lie in the IR spectral range, the more difficult it is to detect the emission. The general rule is that the detectivity or response sensitivity of photodetectors decreases the longer wavelength the radiation to be measured is. This means that the signal / noise ratio of the detected signals generally decreases with increasing wavelength.
• the invention is now based on the knowledge that the difficult to detect certain substances with increasing emission wavelength in the IR spectral range can be used very advantageously to increase protection against counterfeiting.
• a luminescent substance whose emission spectrum is outside is therefore used to secure documents of value the response sensitivity of Si or Ge detectors or at least at the limit of the possibility of detecting a Ge detector.
• the measurement effort for detection with a Ge detector has to be increased many times over or, for example, lead sulfide (PbS), indium arsenide (InAs), gallium indium arsenide (GalnAs) or lead selenide (PbSe) detectors have to be used become.
• PbS lead sulfide
• InAs indium arsenide
• GanAs gallium indium arsenide
• PbSe lead selenide
• the substances suitable for securing authenticity can be substances based on holmium- and thulium-doped host lattices.
• Thulium has emission lines in the wavelength range from 1.6 to 2.1 ⁇ m, in particular in the range from 1.7 and 1.9 ⁇ m, and holmium in the range from 1.8 to 2.1 ⁇ m.
• the emission spectra of the two rare earth metal dopings thus overlap, which increases the emission intensity in the overlap region when the two dopants are excited accordingly. As a result, the emission signal appears more clearly in the background noise.
• Double doping also has the advantage that, based on the emission spectrum, it is not readily possible to draw conclusions about the optically active elements of the luminescent substance.
• more emission lines are available for evaluation. In this way, it becomes more difficult for potential counterfeiters to find out which of the lines are actually evaluated during the check.
• Thulium can only be detected with Ge detectors at a correspondingly high level of measurement complexity, since the response sensitivity of Ge detectors is already very high at a wavelength of 1.6 ⁇ m - 4 -
• holmium can no longer be detected using Ge detectors.
• the emission of both rare earth metals can be detected using PbS, InAs or GalnAs detectors. Since the response sensitivity of these detectors is also very low in the wavelength range from 1.7 to approx.2.1 ⁇ m, the thulium and the holmium must be used in a host grating which ensures the highest possible effectiveness of the dopants, i.e. ensures the highest possible quantum yield.
• host gratings are used which contain constituents which absorb broadband and which transfer the absorbed energy to the rare earth metal dopings with a high degree of efficiency.
• the quantum yield of the luminescent substances according to the invention is preferably in the range from 50 to 90%.
• the luminescent substance in the respective value document in such a high concentration that the properties of the value document are not adversely affected.
• the maximum concentration depends on various parameters, e.g. the type of contribution or the desired properties (color or the like) of the value document.
• the just permissible concentration of foreign substances is a few% by weight. If the permissible concentration of foreign substances is exceeded, this results in significant changes in the properties of the substance. An excessively high concentration of foreign matter in the paper, for example, reduces the tear strength of the paper. If the luminescent substance has its own color, the concentration of about 0.1% by weight may already be sufficient to change the color of the entire paper. An excessive concentration of foreign substances - 5 -
• a concentration of 1% by weight of a colored luminescent substance can suffice to falsify the overall color impression of the printing ink. If this luminescent substance also serves as a color pigment, on the other hand, the limit concentration can only be reached at the maximum physically possible solids content of approx. 80% by weight.
• the lower limit concentration in the case of colorless or slightly colored, luminescent substances when mixed into the paper pulp is 0.1% by weight.
• the limit concentration can already be 0.01% by weight.
• the concentration is preferably in the range from 0.05 to 1% by weight.
• the lower limit concentration of the luminescent substance in a layer applied to the value document is approximately 1% by weight, for example for colored luminescent substances.
• the concentration is in the range from 1 to 40% by weight, preferably in the range from 10 to 30% by weight.
• the luminescent substances can be introduced into the value document in a wide variety of ways.
• the luminescent substances can be mixed into a printing ink which additionally contains visually visible color additives.
• admixing the luminescent substance to the paper pulp is also possible.
• the luminescent substances can be provided on or in a plastic carrier material which, for example, is at least partially embedded in the paper pulp.
• the carrier material can have the form of a security thread, a mottled fiber or a planchette.
• the plastic or paper carrier material can also be attached to any other object, for example for product security.
• the carrier material is preferably in the form of a label. If the carrier material is part of the product to be secured, as is the case, for example, with tear threads, any other shape is of course also possible.
• value document means banknotes, checks, shares, tokens, ID cards, credit cards, passports and also other documents as well as labels, seals, packaging or other elements for product security.
• the luminescent substances according to the invention have emission spectra which are so far in the IR spectral range that they can only be detected with the detectors available for this range only with a high level of metrological effort, if the maximum value of the document of value to be marked but not the document is changed Amount to be added.
• boundary phosphors Such luminescent substances are referred to below as “boundary phosphors”.
• the detection technology is so complex that the risk of analyzing the measurement parameters is relatively low. But even if the forger knew the existence of the luminescent substance, he could, as already explained, only reproduce it by precisely reproducing all parameters responsible for the luminescence. Luminescent substances with poorer properties either change the properties of the value document sustainably or are no longer detectable in the detection devices.
• Ge detectors of up to approximately 1.8 ⁇ m can be used and that PbS detectors or correspondingly adapted Gaxlnx-i As detectors are preferably used in the range up to 3 ⁇ m.
• the index x is chosen so that the maximum of detectivity is at the desired cut-off wavelength.
• InAs or PbSe detectors can also be used in principle. However, their detectivity is still a factor of ten below that of PbS detectors.
• the maximum detectivity is already in the wavelength range of approx. 3 to 4 ⁇ m, so that they are not optimally suited for the detection of thulium and holmium.
• the boundary phosphor emits in the wavelength range between approximately 1.6 and 2.1 ⁇ m, and here in particular in the range of 1.7 and 2.1 ⁇ m. If one compares this emission spectrum with the detectivity curves of the sensors shown in FIG. 1, it is found that the emission spectrum of the boundary phosphor according to the invention with detectors of high detectivity, i.e. cannot be detected with Si or GaAs detectors. With GeDetectors whose detectivity maximum has already been shifted further into the IR spectral range, parts of the emission spectrum shown in FIG. 2 can just be measured at great expense.
• the host grating for the optically active rare earth metals thulium and holmium has an optically transparent region in the wavelength range from 1 ⁇ m to 10 ⁇ m.
• the host lattice according to the invention also contains iron or chromium as absorbing elements, which absorb practically the entire visible spectral range and thus have a larger excitation range, which is better adapted to broadband illuminating light sources, instead of the individual excitation lines of the holmium occurring in this range. - 10 -
• the boundary phosphors according to the invention preferably have a garnet or perovskite structure.
• host grids with the general formula are used in the case of a garnet structure
• the grid consists of an yttrium aluminum iron garnet.
• the absorption and thus the brightness of any inherent color of the substance can be adjusted via the proportion of non-absorbing aluminum, so that the luminescent substance can also be used in higher concentrations as an additive for lighter printing inks.
• M stands for iron (Fe) or chromium (Cr). - 11 -
• index z the condition 0.01 ⁇ z ⁇ 0.8, preferably 0.1 ⁇ z ⁇ 0.5 and the index y the condition 0.01 ⁇ y ⁇ 0.8, preferably 0.1 ⁇ y ⁇ 0.5 fulfilled.
• the excitation range of these boundary phosphors lies in the visible spectral range and possibly also in the near IR. This area coincides with the radiation area from strong light sources, such as halogen lamps, flash lamps or the like.
• boundary phosphors Some examples of the boundary phosphors according to the invention are explained in more detail below.
• Aluminum-iron mixed garnet (Gd, 7Tmo, ⁇ Hoo, 2Fe, 5Alo, 5 ⁇ 2 ):
• Gadolinium oxide Gadolinium oxide
• Al oxide A1 2 0 3
• 2.07 g of thulium oxide Tm 2 0 3
• the powder is then ground in water in an agitator ball mill until an average grain size of less than 1 ⁇ m is obtained.
• reaction product After cooling, the reaction product is crushed, the flux is washed out with water, chromate formed as a by-product is reduced to chromium (III) sulfate with sulfuric acid / iron (II) sulfate, filtered off and dried at 100 ° C. in air. To achieve the highest possible grain fineness, the powder is then ground accordingly in water in an agitator ball mill.
• the reaction product After cooling, the reaction product is crushed, the flux is washed out with water and dried in air at 100 ° C. To achieve the highest possible grain fineness, the powder is then ground in water in a stirred ball mill.
• the security against forgery is additionally increased if the luminescent substance is used in the maximum concentration for the respective document of value or security element.
• the maximum concentration depends on various parameters, e.g. the type of contribution or the desired property of the value document or security element.
• the security element consists of a label 2, which is composed of a paper or plastic layer 3, a transparent cover - 14 -
• This label 2 is connected to any substrate 1 via the adhesive layer 5.
• This substrate 1 can be documents of value, ID cards, passports, certificates or the like but also other objects to be secured, such as CDs, packaging or the like.
• the luminescent substance 6 is contained in the volume of the layer 3. If layer 3 is a paper layer, the limit concentration of luminescent substance according to the invention is between 0.05 and 1% by weight.
• the border phosphor could also be contained in a printing ink, not shown, which is printed on one of the label layers, preferably on the surface of layer 3.
• the maximum concentration which is still possible according to the invention is in the range from 10 to 40% by weight.
• the luminescent substance in or on a carrier material, which is then attached to an object as a security element, it is also possible according to the invention to provide the luminescent substance directly in the document of value to be secured or on its surface in the form of a coating.

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• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Business, Economics & Management (AREA)
• Accounting & Taxation (AREA)
• Finance (AREA)
• Credit Cards Or The Like (AREA)
• Inspection Of Paper Currency And Valuable Securities (AREA)

Applications Claiming Priority (3)

Publications (1)

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• 1998
  • 1998-02-02 DE DE19804024A patent/DE19804024A1/de not_active Ceased
• 1999
  • 1999-01-29 EP EP99932413A patent/EP0975838A1/de not_active Ceased
  • 1999-01-29 WO PCT/EP1999/000592 patent/WO1999039051A1/de active Application Filing
  • 1999-01-29 CN CNB998000981A patent/CN1138893C/zh not_active Expired - Lifetime
  • 1999-01-29 AU AU32518/99A patent/AU3251899A/en not_active Abandoned
  • 1999-01-29 RU RU99122748/12A patent/RU2203188C2/ru active
  • 1999-01-29 US US09/381,639 patent/US6479133B1/en not_active Expired - Lifetime
  • 1999-01-29 BR BRPI9904815-9A patent/BR9904815B1/pt not_active IP Right Cessation
  • 1999-09-29 NO NO994739A patent/NO994739L/no not_active Application Discontinuation
• 2000
  • 2000-10-10 HK HK00106388A patent/HK1027138A1/xx not_active IP Right Cessation

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