EP1675731B1 - Valuable document - Google Patents

Abstract

The invention relates to a value document, in particular a bank note, having a value document substrate and different feature substances for checking the value document. According to the invention, a first feature substance is incorporated into the volume of the substrate of the value document, and second and third feature substances are applied to the value document substrate in a printing ink jointly and in the form of a coding. The second feature substance is formed by a luminescent substance, and the third feature substance by a material absorbent in a special spectral range. The two substances are used for the value recognition of different user groups.

Description

The invention relates to a value document, in particular a banknote, with a value document substrate and different feature substances for checking the value document.

From the publication WO 97/39428 a document of value is known, the substrate of which has different machine authentisable authenticity features for different security levels in one area. The value document contains a machine authenticated low security feature formed of a single material. For a query, the low security feature returns a yes / no answer indicating the presence or absence of the queried property. The low security feature is used for authenticity testing in applications where a simple detector is used, such as in retail outlets.

Another high-security feature, which can also be authenticated by machine, has difficult-to-prove properties and enables a more in-depth query of the value document, as well as authentication at a much higher level. Examination of the high security feature is complex and takes place, for example, in central banks. This high-security feature is a homogeneous mixture of two substances with different physical properties, such as the excitation wavelength for luminescence emission or coercivity, etc.

That from the WO 97/39428 However, known system has the disadvantage that, although it allows a complex authenticity check of the value documents, but does not allow a statement about the nature or value of the respective value document. However, for a machining of value documents, in particular banknotes, it is also desirable to include the type of document, such as For example, you can enter the currency or denomination of a known currency by machine.

From the US 6,155,605 For example, a system is known in which different feature substances are used for different user groups.

The GB 2 016 370 A describes two feature substances, one absorbing at one emission wavelength of the other.

Based on this, the object of the invention is to propose a generic value document which, in addition to increased counterfeit security, also includes a possibility of value recognition.

In the context of the present invention, value recognition is understood to mean the evaluation of encoded information for a specific user group. The encoded information may, for example, represent the denomination, the currency, the series, the issuing country or other features of the banknote in a banknote.

The object is achieved by the value document with the features of the main claim. A production method for such value documents as well as a respective method for checking or processing such value documents are the subject matter of the independent claims. Advantageous developments of the invention are the subject of the dependent claims.

The value document according to the invention has a first feature substance, which is introduced into the volume of the substrate of the value document, and a second and third feature substance, which is applied to the value document substrate jointly in a printing ink and in the form of an encoding are. In this case, the second feature substance is formed by a luminescent substance and the third feature substance by a material absorbing in the infrared spectral range. As explained in detail below, this combination creates a complex feature system that is very difficult to adjust for a counterfeiter. The feature system allows users from different user communities to both authenticate as well as to recognize the value of the document. The feature substances used by the various user groups or their characteristic properties are completely separated from each other.

For example, users of a user group can use a characteristic property of the first feature substance for authenticity testing and the encoded form of absorbent material for value recognition. Users of another user group can use a characteristic property, in particular the luminescence, of the second feature substance for the authenticity check and use the coding formed by the luminescent substance for value recognition. As a result, users from both user groups can perform a value recognition on the document in addition to an authenticity check without much additional effort. The exact execution of the authenticity check and the value recognition will be described in detail below.

These user groups may be central banks, commercial banks, any trading companies, such as local transport companies, department stores or vending machine operators, etc.

The analysis of the entire feature system is extremely difficult and time-consuming, since for third parties it is not clear which substances and in particular which material properties are used for the examination by the different user groups. Even the knowledge of the procedure of a user group does not yet reveal the substances and methods that are used by the other user groups for authenticity checking and value recognition.

According to a preferred embodiment of the invention, the first feature substance in the volume of the value document substrate is distributed substantially uniformly, so that sufficiently large volume elements of the same size each contain substantially the same amount of the first feature substance. The distribution of the first feature substance can be regular and take place, for example, in a predetermined pattern. However, the first feature substance is preferably introduced into the substrate volume with a random distribution.

The marker can also be introduced into the near-surface volume region of the paper substrate. For this purpose, for example, in the publications are suitable EP-A-0 659 935 and DE 101 20 818 described methods in which the particles of the first marker substance are mixed into a gas stream or a liquid stream and introduced into a wet paper web. The disclosures of said documents are included in the present application in this respect.

The third feature substance chosen is a feature substance absorbing in the infrared spectral range. Under "infrared spectral range" is understood according to the invention the wavelength range from 750 nm and greater, preferably 800 nm and greater. In particular, the third feature substance is preferably essentially colorless in the visible spectral range or has only a weak intrinsic color. The third feature substance is then not recognizable under ordinary lighting conditions or appears only slightly conspicuous. In addition, unlike a luminescent substance, the infrared absorbing feature substance does not provide an active signal that would facilitate analysis of the material used.

Advantageously, the third feature substance, even at a wavelength of about 800 nm, still no significant absorption, so that it is not detectable with commercially available infrared detectors based on silicon. The third feature substance preferably has a significant absorption only in the spectral range above approximately 1.2 μm, preferably in the spectral range between approximately 1.5 μm and approximately 2.2 μm. The infrared absorption of the third feature substance is then detectable only with complex and less widespread detectors, which gives the coding formed a high security against counterfeiting.

In preferred embodiments of the invention, for example, a material based on doped semiconductor material is used as the infrared-absorbing feature substance. Even substances containing a metal oxide are suitable and are characterized in particular by their aging resistance. The third feature substance is preferably present in particle form with an average particle size smaller than 50 nm. As a result, visible light is scattered only slightly by the particles, so that the feature substance in the visible is colorless or has only a weak intrinsic color.

Examples of the infrared absorbers used as third feature substance in the invention, which have no appreciable absorption neither in the visible nor at about 800 nm, are about 2,5-cyclohexadienedi-1,4-diylidene-bis [N, N-bis ( 4-dibutylaminophenyl) ammonium] bis (hexafluoroantimonate) having the empirical formula C ₆₂ H ₉₂ N ₆ F ₁₂ Sb ₂ , the dyes ADS 990 MC having the empirical formula C ₃₂ H ₃₀ N ₂ S ₄ Ni, or ADS 1120P having the empirical formula C ₅₂ H ₄₄ Cl ₂ O ₆ from Siber Hegner GmbH, Hamburg. A fourth feature substance is applied to the value document substrate, preferably printed. The fourth feature substance is added to the first feature substance for checking the authenticity of the value document are used.

In addition to the second feature substance, the first feature substance and the fourth feature substance can also be formed by a luminescent substance or a mixture of luminescent substances. For the first and fourth feature substance preferably luminescent substances or mixtures are used which emit in the infrared spectral range and in particular have a complex, difficult to adjust, spectral emissivity characteristic. This emission characteristic can be used in particular to distinguish the luminescent substances from similar luminescent substances. However, it can also be used to generate a coding by the form of the emission or / and excitation spectra of the luminescent substances.

In the value document according to the invention, the third feature substance is formed by an infrared-absorbing feature substance and the first feature substance by a luminescent substance which emits in the absorption region of the third feature substance. This allows to exploit the interaction of the characteristics of the first and third feature substances for reading out the coding, as further described in detail below. The excitation of the first feature substance advantageously takes place in the infrared spectral range, preferably in the spectral range from about 0.8 μm to about 1.0 μm.

Preferably, at least one of the luminescent feature substances is a luminescent substance based on a host lattice doped with rare earth elements. It is also possible for more or all of the luminescent substances to be formed on the basis of such a doped host lattice. These luminescent substances may e.g. be excited that is irradiated directly into the absorption bands of rare earth ions. In preferred variants, absorbent host lattices or so-called "sensitizers" can be used, which absorb the excitation radiation and transferred to the rare earth ion, which then emits with luminescence. It is understood that the host lattices and / or the dopants for the different feature substances can be different in order to obtain different excitation and / or emission regions.

In a preferred embodiment, the host lattice in the visible spectral range and optionally, in particular in the case of the first or fourth feature substance, additionally absorbs up to about 1.1 μm in the near infrared range. The excitation can then take place via light sources, such as halogen lamps, LEDs, lasers, flash lamps or xenon arc lamps, with high efficiency, so that only small quantities of the luminescent substance are required. This makes it possible, on the one hand, to apply the luminescent substance with conventional printing methods, and on the other hand, the small amount of substance makes it difficult to detect the substance used by potential counterfeiters. Absorbs the host lattice in the near infrared up to about 1.1 microns, so easily detectable emission lines of rare earth ions can be suppressed so that only the more expensive emission to be detected remains at longer wavelengths.

In an alternative preferred embodiment, luminescent substances are used which absorb even in the visible spectral range, preferably over the largest part of the visible spectral range, particularly preferably into the near infrared range. Even then, emissions in these more easily accessible spectral ranges are suppressed.

The host lattice may, for example, have a perovskite structure or a garnet structure and be doped with a rare earth element emitting in the infrared spectral region, such as praseodymium, neodymium, dysprosium, holmium, erbium, thulium or ytterbium. Further possible embodiment of the host lattice and the dopant are in the EP-B-0 052 624 or the EP-B-0 053 124 whose disclosures are included in the present application in this respect.

According to an advantageous embodiment of the value document according to the invention, the coding extends over a predominant part of a surface of the value document, in particular over the substantially entire surface of the value document. As a result, a further increased security against forgery of the value document can be achieved, since gaps or inserted parts of others, including other genuine documents, make themselves felt as a disruption of the coding.

For example, the coding or a part of the coding may be provided with a certain offset from document to document in the case of similar documents, such as banknotes of the same denomination. If the documents are produced in endless format, this can be be achieved by using a pressure roller whose circumference is a non-integer multiple of the document size. A series of successive documents can then contain a coding of the same content or the same form, wherein the individual documents are at the same time distinguishable from each other due to the different offset. In sheetfed printing, the same result can be achieved if, in accordance with the desired repetition rate, a plurality of printing plates with mutually offset codings or coding parts are used.

The encoding formed by the second and third feature substances may represent any type of characters or patterns, such as an alphanumeric string. In the context of the invention, however, it is preferred that the coding represents a barcode. A barcode is understood to mean any one- or two-dimensional pattern consisting of strips or surfaces with the feature substances ("bars") and strips or surfaces lying between the bars without feature substances ("gaps"). As a rule, the bar / space sequence represents a binary sequence of numbers which represents any, even encrypted, information about the value document.

The barcode may in particular be invisible to the naked eye and detectable only after irradiation with a suitable light source by its emission or absorption in a specific spectral range. Barcodes are particularly suitable for machine read-out and provide an almost error-free reading result, especially in combination with check digits. For example, standard formats such as the code 2/5, the code 2/5 interleaved, the code 128 or the code 39, as well as special formats used only for the value documents according to the invention come into question as barcodes. Also, two-dimensional barcodes, which is a particularly highly condensed record and provide increased redundancy, making them insensitive to production tolerances can be used.

The value document substrate is preferably a printed or unprinted cotton fiber paper, cotton / synthetic fiber paper, a cellulose-containing paper or a coated, printed or unprinted plastic film. A laminated multilayer substrate is also possible. The material of the substrate is not essential to the invention insofar as it allows only the introduction or application of the respectively required feature substances. It is understood that the value document can be provided in addition to the aforementioned substances with other feature substances or other printing layers.

The value documents according to the invention are preferably banknotes, shares, credit cards, identity cards or identity cards, passports of any kind, visas, vouchers, etc.

The application of the second and third feature substance on the value document substrate is carried out according to the invention with a printing process. In this case, for example, a gravure, screen, high-pressure, flexographic, inkjet, digital, transfer or offset printing process can be used. The printing inks used for this purpose may be transparent or contain additional color pigments which must not impair the detection of the feature substances. In the case of the luminescent substances, they preferably have transparent regions in the excitation region and in the considered emission region of the luminescent substances.

The fourth feature substance can basically be applied in any form and distribution to the value document.

However, it is preferred to also print the fourth feature substance in the form of a code on the value document substrate. In this case, the fourth feature substance according to an advantageous embodiment of a printing ink, in particular a visible ink, be mixed and printed together with this ink on the value document substrate. The fourth feature substance is usually applied separately from the second and third feature substance, but can also be printed together with these in a common ink.

The codings formed by the second and third and fourth feature substances may be the same or different. For example, the second and third feature substance may be applied in the form of a barcode and the fourth feature substance in the form of an alphanumeric character string.

In an advantageous development of the invention, the value document has a further printing layer which partially or completely covers the regions of the value document provided with the second and third feature substance. In particular, the printed layer in the visible spectral range can be opaque and transparent or translucent in the emission region of the second feature substance and / or in the absorption region of the third feature substance. The print layer then hides the presence of the second and third feature substances in the visible spectral range, but allows detection of the luminescence of the second feature substance or the absorption of the third feature substance at the respective wavelengths. If the print layer completely covers the areas of the value document provided with the second and third feature substance, it must be present both in the emission area of the second feature substance and in the absorption area of the third feature substance may be transparent or translucent to allow detection of the respective feature characteristics.

It is understood that further feature substances, for example to further increase the security against counterfeiting or to involve other user groups, can be applied or introduced into the substrate.

In a method for checking or processing a value document described above, the authenticity of the value document is checked and a value recognition of the document is performed by checking at least one characteristic of the first and / or second feature substance for checking the authenticity of the value document and the second and / or third feature substance formed coding is used to recognize the value of the value document. The authenticity and the value recognition of the value document are preferably determined by different user groups on the basis of different feature substances. In other words, if the user belongs to a first user group, the authenticity of the value document is determined based on at least one characteristic property of the first feature substance and the value recognition is carried out by means of the coding represented by the third feature substance. If the user belongs to a second user group, the user stands for the Authenticity recognition at least one characteristic property of the second feature substance and for the value recognition the coding formed by the second feature substance. The test systems of the different user groups are thus completely decoupled, since different feature substances are evaluated. That is, if forgeries occur in a user group, this vulnerability affects no other user groups.

By means of the fourth feature substance, the examination or processing by a user of the first user group can take place by using at least one characteristic property of the first and fourth feature substance for checking the authenticity of the value document. The coding formed by the third feature substance is also used here for recognizing the value of the value document. For example, a part of the users from the first user group can use the first feature substance for authentication, another part the fourth feature substance. The examination or processing by users of the second user group remains unchanged.

In both method variants, the value recognition by a user of the first user group preferably takes place in that the coding is irradiated with radiation from the absorption region of the third feature substance, the absorption of the coding at a wavelength from the irradiation region is determined and the value recognition is performed on the basis of the measured absorption becomes.

The irradiation of the coding takes place in the infrared spectral range and the absorption is advantageously determined by a spatially resolved measurement of the transmitted and / or remitted infrared radiation.

The recognition of value by a user of the first user group takes place in that at least a subarea of the value document is irradiated with radiation from the excitation region of the luminescent first feature substance, the emission of the first feature substance at a wavelength from the absorption region of the third feature substance is determined and the value recognition is performed on the basis of the measured emission.

This is due to an interaction between the properties of the first and third feature substances, wherein the first feature substance is a luminescent substance which emits in the absorption region of the third feature substance. The absorption of the third feature substance is not determined by a remission or transmission measurement, as in the previously described method, but by the luminescence emission of the first feature substance locally suppressed in the region of the coding. In this case, the third feature substance does not absorb at a certain emission wavelength of the first feature substance, while it absorbs at least a part of the emission radiation at a certain emission wavelength of the fourth feature substance. The emission of the first feature substance at a particular wavelength is thus the expected 100%, while the emission of the fourth feature substance at another particular wavelength is e.g. 50%, based on the expected 100%. With the help of these special emission and absorption characteristics in the whole spectrum it is so easy to detect a specific absorber. It is therefore not sufficient in the forgery to use any absorbent material, but also the absorber must have a very specific spectrum, which interacts with the spectrum of the first and fourth feature substance.

Again, the irradiation is preferably carried out in the infrared spectral range, for example at 0.8 .mu.m to 1.0 .mu.m, and the emission is measured in a spatially resolved manner for the detection of the local absorption.

The described method additionally allows normalization of the measured emission profile. If the absorbing coding imprint is on the front side of the document of value, in addition to the absorption-modulated front-side luminescence emission, the backside luminescence emission is measured as well. In this case, the value document is irradiated with excitation light from the rear side and the substantially constant backside emission of the first marking substance is recorded as a reference value. The front emission can then be related to this reference value and thereby normalized. Alternatively, it is also possible to normalize the modulated front-side luminescence emission to the emission of the unprinted areas.

Users of the second user group irradiate the coding for the authenticity check and value recognition with advantage with radiation from the excitation area of the second feature substance. The emission of the coding is determined at at least one wavelength from the emission range of the second feature substance and the verification of the authenticity and / or the value determination is carried out on the basis of the determined emission. The second feature substance is preferably irradiated with visible and / or infrared radiation and the emission of the second feature substance is determined in the infrared spectral range.

In all described process variants, the irradiation is advantageously carried out with a light-emitting diode or laser diode.

The use of the infrared-absorbing third feature substance for the first user group has increased security compared to the luminescence coding formed by the second feature substance. In addition to the advantages already mentioned, the automatic readability of the IR coding only slightly disturbed by an underlying background pressure. On the other hand, contamination in the infrared spectral range is much less disturbing than in the visible and in the ultraviolet spectral range. The signal-to-noise ratio of a measuring head is also significantly better for remission measurements than for luminescence measurements, so that a higher resolution can be achieved.

Further embodiments and advantages of the invention are explained below with reference to FIG. For better clarity, a representation true to scale and proportion is omitted in the figures.

Fig.1

eine schematische Darstellung einer Banknote nach einem Aus- führungsbeispiel der Erfindung,

Fig. 2

einen Schnitt durch die Banknote von Fig.1 entlang der Linie II-II,

Fig. 3

den Verlauf der Infrarotabsorption der Banknoten von Fig.1 und Fig. 5, jeweils entlang der Linie III-III,

Fig. 4

in (a) den Verlauf der auf der Rückseite der Banknoten entlang der Linie III-III gemessenen Lumineszenzemission, in (b) den Verlauf der auf der Vorderseite der Banknoten ent- lang der Linie III-III gemessenen Lumineszenzemission, und

Fig. 5

eine schematische Darstellung einer Banknote nach einem an- deren Ausführungsbeispiel der Erfindung.

Show it:

Fig.1

1 a schematic representation of a banknote according to an embodiment of the invention,

Fig. 2

a section through the banknote of Fig.1 along the line II-II,

Fig. 3

the course of the infrared absorption of banknotes of Fig.1 and Fig. 5 , each along the line III-III,

Fig. 4

in (a) the course of the luminescence emission measured on the back of the banknotes along the line III-III, in (b) the course of the luminescence emission measured on the front side of the banknotes along the line III-III, and

Fig. 5

a schematic representation of a banknote according to another embodiment of the invention.

The invention will now be explained using the example of a banknote. Fig.1 and 2 show a schematic representation of a banknote 10, which is equipped with different feature substances for testing by different user groups. It shows Fig.1 the banknote 10 in supervision and Fig. 2 a cross section along the line II-II of Fig.1 ,

How best in Fig. 2 1, a first feature substance 14 in the form of particles is distributed uniformly in the volume of the paper substrate 12 of the banknote 10. The particles of the first feature substance 14 can be added to the paper or fiber mass prior to sheet formation or can be introduced into the fiber matrix only after layer formation.

In the exemplary embodiment, the first feature substance 14 is a mixture of different luminescent substances, which emit radiation after excitation with a complex spectral distribution which is difficult to track in the infrared spectral range.

A second feature substance 16 and a third feature substance 18 are printed together in a printing ink 20 and in strip form on the front side of the banknote 10. The width of the individual strips 22 and the width of the respective intermediate spaces 24 represent a bar code in which the denomination and the currency of the banknote 10 are stored encrypted. The bar code 22, 24 extends substantially over the entire surface of the banknote 10.

The second feature substance 16 is formed in the exemplary embodiment by a luminescent substance and the third feature substance 18 by an infrared absorbing material. In contrast to the first feature substance 14 is the second feature substance 16 specifically chosen so that its luminescence can be easily excited and detected with commercially available detectors.

The infrared absorbing third feature substance 18 is transparent in the visible spectral range up to wavelengths of about 0.8 μm, so that its presence in the bar code 22, 24 can neither be detected by the naked eye nor can be detected with commercially available infrared detectors.

The authenticity check and the value recognition can now be carried out by two different user groups on the basis of different combinations of the feature substances 14, 16 and 18, or their arrangement. The banknote 10 of the embodiment is designed for a first user group with high security requirements and a second user group with comparatively low security requirements.

For example, the second user group may be simple, cash-accepting machines in parking lots or vending machines. For this use inexpensive detection devices for authenticity testing and value recognition are particularly useful.

A user of the second user group checks the authenticity of a banknote 10 by irradiating the banknote with light from the excitation area of the second feature substance 16 and the detection of the corresponding luminescence signal. If a correct luminescence signal is received, the banknote is rated as genuine by the user. Due to the choice of the luminescent substance 16, this detection can be carried out with commercially available, inexpensive detectors. If the banknote is recognized as genuine, its value can, if necessary, also be formed by the luminescent substance 16 coding 22, 24 are taken. Of course, the authenticity check and the value recognition can also be carried out in one step.

The first user group with its higher security requirements is the first feature substance 14 with its complex spectral emission as a mark of authenticity. The first group of users may, for example, include banks in which the authenticity of the banknotes is checked with high-quality and sophisticated detectors. Here, a banknote for the examination is irradiated with light from the excitation area of the first feature substance 14 and the correct spectral response of the feature substance is evaluated. The authenticity check is preferably based not only on the determination of the correct luminescence emission, but also on a more detailed analysis of the emission spectrum, wherein half-widths and / or luminescence peak intervals and / or decay times etc. are evaluated.

The value recognition of the banknote is carried out by a user of the first user group with the aid of the infrared absorbing third feature substance 18. As already mentioned, the feature substance 18 in the near infrared is transparent, but absorbs at longer wavelengths, in the embodiment in the range of 1.5 microns. The information content of the bar code 22, 24 can thus be read out with a sophisticated infrared detector at a wavelength of 1.55 μm by a remission measurement. Fig. 3 schematically shows the course of the measured at 1.55 microns infrared absorption 26 along the line III-III of Fig.1 , From the sequence of absorption maxima 28 and absorption minima 30, the information coded in the bar pattern 22, 24 can be read in a known scheme.

The elaborate evaluation of the coding 22, 24 with the aid of the infrared absorbing third feature substance simultaneously performs an additional authenticity check of the banknote 10 for the first user group. Namely, if no invalid coding is recognized in the value recognition in the infrared absorption 26, the banknote can be classified as not authentic even if the examination of the first feature substance did not reveal any abnormality. A simulation of the coding with the luminescent second feature substance, for example due to an analysis of a detection device of the second user group, is not sufficient to deceive the value recognition of the first user group.

The two user groups use non-overlapping feature substance systems for authentication and value recognition. This results in a significant advantage that an analysis of a comparatively easily accessible device for authenticating the second user group gives no indication of the procedure and the basics of the authentication or the value recognition of the first user group. The system has the advantage that both user groups check the identical information, since the two value recognition substances are printed in a common mixture in coded form, and yet the value recognition is completely decoupled by the examination of different physical properties.

In addition to the feature substances mentioned, a fourth feature substance 32 in the form of a further coding 34 is applied to the banknote 10. The further coding can also be designed as a barcode or as an alphanumeric string, as in the Fig.1 indicated. The fourth feature substance is another luminescent substance 32 admixed with a visible ink 36. With the Printing ink 36 and the luminescent substance 32 is a printed image, for example the denomination and the currency of the note, or a graphic motif printed on the banknote substrate 12.

In the exemplary embodiment, the fourth feature substance 32 is a luminescent substance based on a host crystal doped with a rare earth element which, upon excitation in the visible spectral range, exhibits luminescence in the infrared spectral range at approximately 2.0 μm and does not emit in the visible and in the near infrared. The luminescence of the fourth feature substance 32 can not be detected with widespread detectors which are sensitive to a maximum of 1.1 μm. The fourth feature substance 32 can therefore be used by the users of the first user group as an alternative or in addition to the first feature substance 14 for a high-quality authenticity check.

Another variant of the value recognition of the banknote by a user of the first user group is now in connection with the Fig. 4 explained. For this variant, the first feature substance 14 selected is a luminescent substance which emits above 1.2 μm, in particular at the subsequently used test wavelength of 1.55 μm. As mentioned, luminescent substances based on rare earth-doped host lattices have such an IR emission.

Fig. 4 (a) shows the course 40 of the measured on the back of the bill luminescence emission along the line III-III at the test wavelength of 1.55 microns after excitation of the first feature substance 14. Since the first feature substance 14 is evenly distributed in the substrate 12 and the banknotes back no absorbent structures contains, results in a constant Emission signal 40, whose size can serve as a reference value for the subsequent front measurement.

If the luminescence emission is measured along the line III-III on the front side of the banknote 10, the result is the in Fig. 4 (b) Course shown 42. At the points where the line III-III crosses the strips 22 of the coding, the luminescence emission of the first feature substance 14 is absorbed by the third feature substance 18, so that a minimum 44 in Lumineszenzverlauf 42 is formed. By contrast, the emitted radiation passes through the gaps 24 of the coding, possibly with a certain weakening by further printed layers of the banknote, and leads in the luminescence measurement to regions 46 with a large luminescence signal. The encoded information can be read out again via the width of the luminescence maxima and minima.

The last-described readout method for the coding 22, 24 is based on an interaction of the substance properties of the luminescent substance 14 and the infrared absorbing feature substance 18, which is extremely difficult to reproduce for a counterfeiter and therefore offers a very high counterfeit protection.

Again with reference to Fig. 1 the first strip 22 of the coding is arranged with a certain distance 48 from the left edge of the banknote 10. If this distance 48 is varied for different banknotes of the same series, for example by using different printing plates with different spacing 48, this results in additional protection against counterfeiting, since gaps or inserted parts of other banknotes make themselves felt as a disturbance in the coding 22, 24 for both user groups ,

For example, it may be provided that only certain combinations of strip widths 22 and gap widths 24 form permissible codes. Too broad or too narrow strips, as they can easily occur during manipulation attempts on the banknote, are recognized as inadmissible during the examination of the banknotes and rejected the banknote as manipulated.

Another embodiment of a banknote 50 according to the invention is shown in FIG Fig. 5 shown. Unlike the banknote of Fig.1 For example, in the case of the banknote 50, the strip coding 52, 54 is tilted by a certain angle α against the perpendicular. The first strip 52 has at the lower edge of the banknote 50 a certain distance 56 from the left edge of the note, which is varied within the banknotes of a series. Manipulation attempts on the banknote 50 are thus easily recognizable for both user groups, since gaps or inserted parts of other notes immediately lead to a sensitive disturbance of the tilted stripe pattern.

If the absorption or emission is measured only along the line III-III, the same results as described above in connection with the bank note 10 of Fig.1 described.

Claims (31)

1. A value document, in particular bank note, having a value document substrate and different feature substances for checking the value document, a first feature substance (14) being incorporated into the volume of the substrate of the value document, and second (16) and third (18) feature substances being applied to the value document substrate in a printing ink jointly and in the form of a coding, the second feature substance (16) being formed by a luminescent substance, and the third feature substance (18) by a material absorbent in the infrared spectral range, characterized in that the first feature substance (14) is formed by a luminescent substance emitting in the absorption range of the third feature substance (18), the third feature substance (18) not absorbing at a certain emission wavelength of the first feature substance (14), and a fourth feature substance (32) is applied to the value document substrate, preferably printed thereon, which is different from the first to third feature substance (18) and is formed by a luminescent substance, the third feature substance (18) absorbing at least part of the emission radiation at a certain emission wavelength of the fourth feature substance (32).
2. The value document according to claim 1, characterized in that the first feature substance is distributed substantially uniformly within the volume of the value document substrate.
3. The value document according to claim 1 or 2, characterized in that the third feature substance is substantially colorless or has only weak inherent color in the visible spectral range.
4. The value document according to any of claims 1 to 3, characterized in that the third feature substance absorbs significantly in the spectral range above about 1.2 µm, preferably in the spectral range from about 1.5 µm to 2.2 µm.
5. The value document according to at least one of claims 1 to 4, characterized in that the third feature substance has no significant absorption at a wavelength of about 0.8 µm.
6. The value document according to at least one of claims 1 to 5, characterized in that the third feature substance comprises a doped semiconductor material or a metal oxide.
7. The value document according to at least one of claims 1 to 6, characterized in that the third feature substance is present in the printing ink in particle form with an average particle size smaller than 50 nm.
8. The value document according to at least one of claims 1 to 10, characterized in that the first and/or fourth feature substance is formed by a luminescent substance or a mixture of luminescent substances.
9. The value document according to at least one of claims 1 to 7, characterized in that at least one of the feature substances is formed on the basis of a host lattice doped with rare earth elements.
10. The value document according to at least one of claims 1 to 9, characterized in that the coding extends over a predominant part of a surface of the value document, in particular over the substantially total surface of the value document.
11. The value document according to at least one of claims 1 to 10, characterized in that the coding represents a bar code.
12. The value document according to at least one of claims 1 to 11, characterized in that the coding is information about the value document, the information preferably being present in encrypted form.
13. The value document according to at least one of claims 1 to 12, characterized in that the value document substrate comprises a printed or unprinted cotton paper.
14. The value document according to at least one of claims 1 to 13, characterized in that the value document substrate comprises a printed or unprinted plastic film.
15. The value document according to any of claims 1 to 14, characterized in that the fourth feature substance is printed on the value document substrate together with a printing ink, in particular a visible printing ink, in the form of a printed image.
16. The value document according to claim 15, characterized in that the printed image represents a coding, in particular a bar code or an alphanumeric character string.
17. The value document according to at least one of claims 1 to 16, characterized in that the value document has a further printed layer which partly or completely covers the value document areas provided with the second and third feature substances.
18. The value document according to claim 17, characterized in that the further printed layer is opaque in the visible spectral range and is transparent or translucent in the emission range of the second feature substance and/or in the absorption range of the third feature substance.
19. The value document according to claim 15 or 16 and according to claim 17 or 18, characterized in that the further printed layer is formed by the printing ink containing the fourth feature substance.
20. A method for producing a value document according to any of claims 1 to 19, characterized in that the first feature substance is incorporated into the volume of the value document substrate, the second and third feature substances are applied to the value document substrate in a printing ink jointly and in the form of a coding, and a fourth feature substance is applied to the value document substrate, in particular printed thereon.
21. The production method according to claim 20, characterized in that the printing ink containing the second and third feature substances, and the fourth feature substance are applied to the value document substrate as a mixture or as separate substances.
22. The production method according to claim 20 or 21, characterized in that the fourth feature substance is printed on the value document substrate together with a printing ink, in particular a visible printing ink, in the form of a printed image.
23. A method for checking or processing a value document according to any of claims 1 to 19, wherein the authenticity of the value document is checked and a value recognition of the document carried out by using at least one characteristic property of the first and/or second feature substance for checking the authenticity of the value document, and the coding formed by the second and/or third feature substance for the value recognition of the value document, whereby at least one characteristic property of the first feature substance is used for checking the authenticity of the value document, and the coding formed by the third feature substance for the value recognition of the value document, by a user of a first user group, and at least one characteristic property of the second feature substance is used for checking the authenticity of the value document, and the coding formed by the second feature substance for the value recognition of the value document, by a user of a second user group, and additionally at least one characteristic property of a fourth feature substance is used for checking the authenticity of the value document, and the coding formed by the third feature substance is used for the value recognition of the value document, if the user belongs to the first user group, and at least one characteristic property of the second feature substance is used for checking the authenticity of the value document, and the coding formed by the second feature substance is used for the value recognition of the value document, if the user belongs to the second user group.
24. The method according to claim 23, characterized in that, for value recognition by a user of the first user group, the coding is irradiated with infrared radiation from the absorption range of the third feature substance, the absorption of the coding is determined at a wavelength from the irradiation range, and the value recognition is carried out on the basis of the determined absorption.
25. The method according to claim 24, characterized in that the determination of the absorption is performed in spatially resolved fashion.
26. The method according to at least one of claims 23 to 25, characterized in that, for value recognition by a user of the first user group, at least a partial area of the value document is irradiated with infrared radiation from the excitation range of the luminescent first feature substance, the emission of the first feature substance is determined at a wavelength from the absorption range of the third feature substance, and the value recognition is carried out on the basis of the determined emission.
27. The method according to claim 26, characterized in that the determination of the emission is performed in spatially resolved fashion.
28. The method according to claim 26 or 27, characterized in that the emission of the first feature substance is determined on opposite sides of the value document, the value recognition being preferably performed on the basis of a comparison of the emission determined on opposite sides.
29. The method according to at least one of claims 22 to 28, characterized in that, for the authenticity check and value recognition by a user of the second user group, the coding is irradiated with radiation from the excitation range of the second feature substance, the emission of the coding is determined at at least one wavelength from the emission range of the second feature substance, and the check of authenticity and/or the value determination is carried out on the basis of the determined emission.
30. The method according to claim 29, characterized in that the second feature substance is irradiated with visible and/or infrared radiation, and the emission of the second feature substance is determined in the infrared spectral range.
31. The method according to at least one of claims 22 to 30, characterized in that the irradiation is performed with a light-emitting diode or laser diode.

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