Security document or value document comprising a security feature, method for producing same, and method for verifying the authenticity thereof

Abstract

The invention relates to a security document or value document (10) comprising a substrate (11) having a security feature (15), wherein the security feature (15) comprises at least one first printed region (20.1), which is situated at a first position (21.1) on the substrate (11), and at least one second printed region (20.2), which is situated at a second position (21.2) on the substrate (11); the first printed region (20.1) is printed using a first color system (30.1) which has an electroluminescent component (40) and the second printed region (20.2) is printed using a second color system (30.2) which does not have electroluminescent components; the positions (21.1, 21.2) of excitability or non-excitability of electroluminescence of the printed regions (20.1, 20.2) on the security document or value document generate a machine-readable code; and the colors of the two color systems (30.1, 30.2) do not impart any other color impressions to the average observer in the daylight, the color difference Delta E30.1-30.2 of the two color systems (30.1, 30.2) in the daylight being less than 2.5. The invention further relates to a production method and to a method for verifying the authenticity of such security documents and value documents.

Description

[0001] Security or valuable document with a security feature, its manufacturing process and methods for verifying its authenticity

[0002] The present invention relates to a security or valuable document with a security feature, a manufacturing method and a method for verifying the authenticity of the security or valuable document.

[0003] Various security features are used in the production of security and valuable documents such as passports, identity cards, banknotes, etc., to increase protection against counterfeiting. These security features should be difficult to copy but detectable with simple tools. Examples include microprinting, holograms, guilloches (patterns of fine lines that partially overlap or create gaps, thus producing a three-dimensional effect), and fluorescent or phosphorescent patterns that can be detected with a UV detector.

[0004] Ideally, such security features include additional information that is machine-readable. Machine readability can mean that the security feature is checked for its presence using a binary system, or that the security feature contains numerical characters, letters, symbols, or codes that can then be recognized, evaluated, and processed by sensors. Such characters or codes can be used to verify authenticity, for nominal value encoding, or for sorting, for example, different banknote denominations or valuables.

[0005] It is known to print on substrates of security or valuable documents, which can be made of paper or plastic materials such as PC or PVC, using inks containing electroluminescent components. The electroluminescent components in these inks are excited by an alternating electric field and luminesce, and the emitted radiation can then be analyzed.

[0006] WO 2022 / 023 055 A1 discloses a method for printing a valuable or security document substrate with an electroluminescent ink using intaglio printing. Preferably, an electroluminescent ink consisting of electroluminescent pigments and electrically conductive pigments arranged in an electrically insulated manner is used in an intaglio printing device with a wiping cylinder. This allows for a high intensity of luminescence radiation.

[0007] From DE 41 26 051 Al, a security document is known with a security thread, which is printed in a first printing area with a first color system containing an electroluminescent component, and in a second printing area with a second color system not containing an electroluminescent component, wherein the printing areas of the printing ink with the electroluminescent components and the printing ink are covered on both sides with a very thin, highly absorbent layer of metallic aluminum and a polyester film, and the films / layers are laminated together.

[0008] CN 102 114 743 Al teaches a security or valuable document with a security feature in which two printed areas are excited with two E-fields with different frequencies and the electroluminescence spectra of the printed areas obtained at the different frequencies are compared.

[0009] Security or valuable documents with a substrate and a security feature are also known from DE 199 03 988 Al and CN 1 01 398 950 A.

[0010] The object of the invention is to provide security and valuable documents with security features that are machine-readable but not easy to detect and also offer improved protection against counterfeiting.

[0011] This problem is solved by the features of claim 1.

[0012] The safety feature according to the invention comprises a first printing area located at a first position on the substrate and printed with a first color system containing electroluminescent components, and a second printing area located at a second position on the substrate and printed with a second color system without electroluminescent components.

[0013] This means that on the security or valuable document there is a first position where electroluminescence can be excited and a second position where, due to the absence of electroluminescent components, electroluminescence cannot be excited. According to the invention, the respective position of excitability or non-excitability of the printed areas on the security or valuable document—i.e., the location or area on the security or valuable document where electroluminescence can or cannot be generated—generates a machine-readable code by which the authenticity of the document can be verified. The colors of the two color systems do not convey a different color impression to the ordinary observer in daylight; that is, they do not differ, or do not differ substantially, to the normal observer in daylight, so that differences between the two color systems or...Print areas are not, or almost not, visible to the ordinary observer.

[0014] The first and second printing areas can each have a specific shape. For example, they can be rectangular, square, or round. The first and second printing areas together can also represent a character, such as a number. Furthermore, the shape of the first printing area can be the negative of the second printing area; for instance, the first printing area could be the shape of a "5" and the second a cuboid with a cutout "5," so that the first and second printing areas appear as a single, unified surface containing a letter, number, or other symbol detectable in an electric field.

[0015] The first and second printed areas together form a single printed image that, to the average observer in daylight, presents a uniform color impression; that is, the average observer cannot discern any differences between the first and second printed areas. The overall printed image can be a homogeneous-looking area, which may be angular, in the form of a symbol, a number, or otherwise shaped—for example, a uniformly green number that is 100% covered with ink—but it can also be a patterned area or a guilloche, where the pattern appears to the average observer as a single color, and the patterned area, appearing in the single color, comprises a first printed area of ​​a specific shape with electroluminescent properties and a second printed area without electroluminescent properties.

[0016] To ensure that the security feature is not, or essentially not, discernible to the average observer in daylight, the color difference (Delta E) between the two printing inks should be a maximum of 2.5, and preferably a maximum of 1.0. Several studies have investigated the smallest color difference (Delta E) that can still be distinguished by the average observer. Depending on the research objective, these studies determined Delta E to be either 2.5 or 1.0.

[0017] In general, a code is a mapping rule that uniquely assigns to each character of a character set (preimage set) a character or string from a possibly different character set (image set).

[0018] In a preferred embodiment, the security element has several first printed areas at different positions on the substrate, printed with the first ink containing the electroluminescent components, and optionally also several second printed areas at different (other) positions on the substrate, printed with the second ink. The various first printed areas with the electroluminescent components at the different positions allow the generation of a machine-readable code, for example, in the form of images, numbers, letters, or symbols. The shape of the first printed area with the electroluminescent components can, for example, correspond to a number, an ornament, or a letter.

[0019] Preferably, the first printed areas containing the electroluminescent components do not contain any directly understandable characters or symbols, but are themselves encoded, preferably in the form of a binary code, in particular a barcode, 2D code, or QR code, since this further complicates counterfeiting but is easy to read by machine. The code is preferably formed by the shapes and respective positions of the first electroluminescent printed areas.

[0020] The second printed areas do not show electroluminescence in an electric field, but due to the same color impression, they serve to hide the position or spatial arrangement and the shape of the first printed areas in an overall printed image that appears uniform to the ordinary observer.

[0021] The other areas of the security or valuable document not printed with the first printing color, and which do not belong to the second printing areas, also do not exhibit electroluminescence. Unlike the second printing areas, they do not serve to conceal the electroluminescent components and generally have a different color appearance than the first and second printing areas.

[0022] In the variant of a binary code generated by electroluminescent components, particularly barcodes, the first printed area with the first color system containing the electroluminescent component can, for example, represent the "1" value or the black bars in a barcode. All areas not printed with the first color system show no electroluminescence and represent the "0" value. Such a code can be easily read by machine after excitation in an electric field using specialized sensors that capture the luminescence signals with temporal and spatial resolution.

[0023] Such a security feature with an electroluminescence-based code is not easy to counterfeit, as the counterfeiter would need two printing inks. One of these inks must emit at the emission wavelength to be detected after excitation in an electric field, and the two inks must not give the average observer a different overall impression. Furthermore, the counterfeiter would also need to master the printing technique for applying such electroluminescent components, which must subsequently be excitable by an electric field. Additionally, the resulting luminescence signal would have to be readable at the required signal strength, and the counterfeiter would also need to know the binary code to be printed.

[0024] In another variant, the security feature also has a third printed area at one or more additional positions on the substrate of the security or valuable document. This third printed area is printed with a third color system containing electroluminescent components that differ from the electroluminescent components of the first color system and preferably emit at a different wavelength.

[0025] This makes it possible to provide a security or valuable document with two different electroluminescent components emitting at different emission wavelengths, which are arranged at different positions on the security or valuable document and, after common excitation in an electric field, emit at different positions on the security or valuable document with different wavelengths.

[0026] Naturally, the security or valuable document may have additional printed areas at other positions, printed with additional color systems that contain electroluminescent components different from the electroluminescent components of the first and third color systems.

[0027] The color difference Delta E between all three or more color systems should always be a maximum of 2.5 or a maximum of 1.0, so that the individual printed areas are not recognizable.

[0028] Instead of the additional electroluminescent component in the third color system, the third and / or subsequent color systems may also not contain any electroluminescent components, but rather other components with optical properties such as luminescence, IR or UV absorption, etc.

[0029] Depending on the printing technology used, the printed areas can either be adjacent to each other or spaced apart, or may even partially, but not completely, overlap, since ultimately only the generated luminescence signal of the electroluminescent components of the first printing color is read out by the machine.

[0030] If the security or valuable documents are printed with an intaglio printing technique, which creates very fine print patterns that have a slightly raised texture after drying, the printed areas should either touch or be spaced apart. Areas of the very fine print patterns can be printed with the first or second ink color, with the entire area conveying a uniform color impression. However, the areas printed with the first ink color contain the electroluminescent, machine-readable code hidden within the uniform printed image.

[0031] If other printing methods are used, the first and second printed areas may partially overlap. In this case, the first printed area with the first color system containing the electroluminescent components is detected, regardless of the superimposed second color system without electroluminescent components.

[0032] In a preferred embodiment, the printing ink is applied to the substrate by means of offset, simultaneous, relief, planographic, intaglio, or contact printing. This allows the inventive method to be carried out on printing presses designed for the production of security or valuable documents.

[0033] The printing inks used according to the invention are generally high-viscosity printing inks suitable for offset, simultaneous, letterpress, planographic, intaglio and / or contact printing. Such printing inks contain inorganic and / or organic pigments and binders.

[0034] Generally, the binder content is between 55% and 95% by weight, and preferably between 80% and 98% by weight, and the functional pigment content is between 0.1% and 40% by weight, and preferably between 12% and 30% by weight. The printing inks can be UV-curable, oxidatively drying, or physically reactive. These printing inks are not solvent-based. If desired, the high-viscosity printing inks can also contain fluorescent dyes or IR absorbers as an additional safety feature.

[0035] Substances with electroluminescent properties are generally particulate materials that may contain inorganic compounds, such as ZnS or CdS, doped or activated with metals like Cu, Mn, or Ag. Particulate luminescent substances based on silicates, aluminates, phosphates, tungstates, germanates, borates, etc., predominantly activated with Mn, Sr, or rare earth elements, can also be used, particularly substances based on ZnzSiOuMn, or particulate organic polymers or mixtures of the aforementioned compounds. These substances emit visible radiation after excitation in an alternating electric field. Preferably, the emission of visible light occurs solely or predominantly through excitation in an alternating electric field.

[0036] To achieve good machine readability with sufficiently high electroluminescence intensity, the first printing ink should preferably contain transparent or opaque electrically conductive pigments in addition to the electroluminescent substances, as their presence increases the electroluminescence intensity and thus improves machine readability. Preferably, the electrically conductive pigment has at least one electrically conductive layer, for example, consisting of the group consisting of TiC, synthetic or natural mica, other layered silicates, glass, magnesium silicate hydrate / SiO₂, (Sn / Sb)O₂, SiO₂, or Al₂O₃.

[0037] For intaglio printing, the printing ink containing the electroluminescent components can, for example, be formed from electroluminescent pigments and electrically conductive pigments arranged in an electrically insulated manner relative to these, wherein the ratio of the number of electroluminescent components to the number of electrically conductive pigments is preferably between 0.2 and 0.7 and / or the ratio of the number of electroluminescent components to the number of electrically conductive pigments is preferably between 0.3 and 0.5.

[0038] The invention also relates to a method for producing a security or valuable document, in which the first printing area at the first position on the security element is printed with the first color system and the second printing area is printed with the second color system simultaneously or successively onto the substrate, preferably by means of intaglio, offset, relief, gravure, digital, simultaneous, planographic or contact printing.

[0039] The invention also relates to a method for the automated verification of the authenticity of the security feature. Verification of the authenticity of the security feature is achieved by placing the security or valuable document in an electric field in which the electroluminescent components of the first printing ink are excited and luminesce, while the second printing ink remains off. Preferably, the security or valuable document is transported through the stationary alternating electric field at a constant speed. A stationary sensor located within the electric field provides a time-dependent signal profile of the luminescence intensity.Due to the constant transport speed, the time-dependent progression of the luminescence intensity corresponds to the arrangement of the first color system with the electroluminescent components, and thus the machine-readable code, which depends on the position and shape on the security or valuable document.

[0040] The invention, as well as further advantageous embodiments and developments thereof, are described and explained in more detail below with reference to the examples shown in the drawings. The features that can be derived from the description and the drawings can be applied individually or in any combination according to the invention. The drawings show:

[0041] Figure 1 shows a banknote with a security feature featuring different printing areas.

[0042] Figure 2 a) the security feature from Fig. 1 and b) the time course of the luminescence intensity during machine evaluation of the security element from Figure 2a) according to Figure 3,

[0043] Figure 3 shows a schematic representation of the principle of machine-readable evaluation of the security feature.

[0044] Figure 4 shows a security feature with 8 different print areas of varying widths, and Figure 5 shows the barcode obtained from the print areas in Figure 4.

[0045] Figure 1 schematically shows a banknote 10 with a value of 50. Both the 5 and the 0 are divided into a right and a left part by an imaginary vertical line. The numbers 5 and 0 each form a security feature 15 with a first printed area 20.1, 20.1' with electroluminescent components 40 at the first and third positions 21.1, 21.3 in the left part of the number, and a second printed area 20.2, 20.2' without electroluminescent components at the second and fourth positions 21.2, 21.4.

[0046] Figure 2a shows the security feature from Figure 1 again with the electroluminescent components 40 in the first printed area 20.1, 20.1'. The first printed area 20.1, 20.1' is printed at the first and third positions 21.1, 21.3 with the first printing ink 30.1, which contains electroluminescent components 40. The second printed area 20.2, 20.2' at the second and fourth positions 21.2, 21.4 is printed with the second printing ink 30.2, which does not contain electroluminescent components.

[0047] The colors (30.1, 30.2) of the printed areas 20.1, 20.1', 20.2 and 20.2' are indistinguishable to the average observer; all printed areas 20.1, 20.2, 20.1' and 20.2' appear the same color to the average observer. The average observer only recognizes the numbers 5 and 0 in the same color.

[0048] If the security document 10 with the security feature shown in Figure 2a) is transported in the direction of the arrow at a constant speed through an alternating electric field 60 according to Figure 3, the electroluminescent components 40 are excited at the moment the printed area with the electroluminescent components 40 enters the electric field 60, and then emit luminescent light. The emission is measured by a sensor 61 located in the electric field, which measures the intensity of the luminescent radiation II of a specific wavelength at the instant the luminescent components 40 move past the sensor 61. Due to the constant transport speed, the sensor 61 ultimately determines the presence or absence of luminescent radiation at the instant the components move past the sensor, i.e.,The positions or areas containing the electroluminescent components 40 on the banknote 10, as shown in Figure 2b), and thus the code hidden by the position of the electroluminescent components 40 on the security document 10. An evaluation according to Figure 3 yields a barcode.

[0049] Figure 4 schematically depicts a security feature with eight different rectangular printed areas 20.1 ... 20.8 at eight different positions 21.1 ... 21.8, which differ in width and the type of printing ink 30.1 with electroluminescent components 40 or 30.2 without electroluminescent components. It is known to those skilled in the art that, for resolution reasons, the different printed areas 20.1 ... 20.8 must be sufficiently spaced apart, generally between 2 and 15 mm and preferably between 5 and 10 mm. All printing inks 30.1 and 30.2 appear the same to the average observer.

[0050] If the security feature from Figure 4 is moved again in an electric field 60 past a sensor 61 for measuring the luminescence intensity II according to Figure 3, a temporal and thus corresponding spatial profile of the luminescence intensity II according to Figure 5 is obtained, which corresponds to a barcode. The presence of luminescence radiation is assigned, for example, the value 1 and the absence of luminescence radiation the value 0.

[0051] Such a code, generated by the electroluminescent components at a specific location on the security document, can be read at high speed using a suitable machine and sensors. Furthermore, due to the printing areas, which are indistinguishable to the ordinary observer, it is not easy for a forger to recognize. The security of such a machine-readable security document can be further increased by using not just one electroluminescent component 40, but two or more different electroluminescent components 40, 41 for a first and a second printing area, which differ in their emission wavelength.

[0052] Reference symbol list

[0053] 10 Banknote, security document

[0054] 11 Substrat

[0055] 20 Print area

[0056] 20.1 first printing area

[0057] 20.2 second printing area

[0058] 20. n nth pressure range

[0059] 21st position

[0060] 21.1 first position

[0061] 21.2 second position

[0062] 21. n nth position

[0063] 22 Overall print image

[0064] 30 printing colors

[0065] 30.1 First printing ink with electroluminescent component 40

[0066] 30.2 Second printing color without electroluminescent component

[0067] 30.3 third printing color with electroluminescent component 41, which is different from vc 40

[0068] 30th printing color

[0069] 40 electroluminescent component

[0070] 41 other electroluminescent component than 40

[0071] 60 electric field

[0072] 61 Luminescence sensor

Claims

AMENDED CLAIMS received by the International Bureau on 6 October 2025 (06.10.2025) 1. Security or valuable document (10) comprising a substrate with a security feature, wherein the security feature comprises a first printed area (20.1) arranged at a first position (21.1) on the substrate and a second printed area (20.2) arranged at a second position (21.2) on the substrate, wherein the first printed area (20.1) is printed with a first color system (30.1) having an electroluminescent component (40) and the second printed area (20.2) is printed with a second color system (30.2) that does not have an electroluminescent component, and wherein the positions (21.1, 21.2) of the excitability or non-excitability of electroluminescence of the printed areas (20.1, 20.2) on the security or valuable document (10) generate a machine-readable code, characterized in that the colors of the two color systems (30.1, 30.2) do not convey a different color impression to the ordinary observer in daylight, where the color difference Delta E30.1-30.2 of the two color systems (30.1, 30.2) is less than 2.5 in daylight.

2. Security or valuable document (10) according to claim 1, characterized in that the overall printed image consisting of the first (20.1) and the second printing area (20.2) is a flat or patterned printed image which has a uniform color appearance in daylight.

3. Security or valuable document (10) according to one of the preceding claims, characterized in that the color difference Delta E30.1-30.2 of the two color systems (30.1, 30.2) is less than 1.0 and particularly preferably less than 0.8 in daylight. AMENDED SHEET (ARTICLE 19) 4. Security or valuable document (10) according to one of the preceding claims, characterized in that the security element has several first printing areas (20.1) at different positions (21.1 ..

21. In) of the substrate which are printed with the first printing ink (30.1) with the electroluminescent components (40), and optionally also several second printing areas (20.2) at different positions of the substrate which are printed with the second printing ink (30.2).

5. Security or valuable document (10) according to one of the preceding claims, characterized in that a machine-readable code, for example in the form of images, numbers, letters or symbols, in particular a binary code, preferably a barcode, 2D code or QR code, is generated by the first printing areas (20.1) with the electroluminescent components (40) on the position(s) (21.1 ..

21. In).

6. Security or valuable document (10) according to one of the preceding claims, characterized in that the security feature has at least a third printed area (20.3) at at least one further position (21. n) which is printed with a third color system comprising electroluminescent components (41) that differ from the electroluminescent components (40) of the first color system (30.1) and optionally further printed areas (20. n) with further color systems (30. n) are provided at further positions which have electroluminescent components 42(1..n) that differ from the electroluminescent components (42) of the first (30.1) and third color system.

7. Security or valuable document (10) according to one of the preceding claims, characterized in that the printing areas (20.1, 20.2) are adjacent or spaced apart from each other or partially, but not completely, overlap. AMENDED SHEET (ARTICLE 19) 8. Security or valuable document (10) according to one of the preceding claims, characterized in that the electroluminescent components (40) of the first printing ink (30.1) are selected from the group of inorganic compounds, in particular ZnS or CdS doped with metals, especially Cu, Mn or Ag, or the silicates, aluminates, phosphates, tungstates, germanates, borates activated with Mn, Sr or rare earths or the substances based on ZnzSiOu Mn or the particulate organic polymers or mixtures of the aforementioned compounds.

9. Security or valuable document (10) according to one of the preceding claims, characterized in that the first printing ink (30.1) contains, in addition to the electroluminescent components (40), transparent or non-transparent electrically conductive pigments, which preferably have an electrically conductive layer, in particular consisting of the group consisting of TiOz, synthetic or natural mica, other layered silicates, magnesium silicate hydrate / SiC, (Sn / Sb)O2, glass, SiC or Al2O3.

10. Security or valuable document (10) according to one of the preceding claims, characterized in that the first printing ink (30.1) comprises electrically insulated electrically conductive pigments in addition to the electroluminescent components (40), wherein the ratio of the number of electroluminescent components (40) to the number of electrically conductive pigments is preferably between 0.2 and 0.7 and / or the ratio of the number of electroluminescent components (40) to the number of electrically conductive pigments is preferably between 0.3 and 0.

5.

11. Method for producing a security or valuable document (10) according to one of claims 1 to 10, characterized in that the first printing area (20.1) is equipped with the first color system (30.1) and the second printing area (20.2) is equipped with the second AMENDED SHEET (ARTICLE 19) The color system (30.2) is printed onto the substrate simultaneously or sequentially, preferably by means of intaglio printing, offset, letterpress, gravure, digital, simultaneous, planographic or contact printing.

12. Method for verifying the authenticity of a security or valuable document (10) according to one of claims 1 to 10, characterized in that the security or valuable document (10) is transported through an electric field (60) in which the time-dependent course of the luminescence intensity generated on the security or valuable document (10) by the excitation of the electroluminescent components (40) in the electric field (60) is measured by stationary luminescence sensors (61) located in the stationary electric field (60).

13. Method according to claim 12, characterized in that the transport of the security or value document (10) takes place at a constant speed through the electric field (60) and / or the time-dependent course of the luminescence intensity is the machine-readable code. AMENDED SHEET (ARTICLE 19)

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