VALUABLE DOCUMENT HAVING A SUBSTRATE ELEMENT AND A FOIL ELEMENT, AND METHOD FOR CLASSIFYING A VALUABLE DOCUMENT

Abstract

A value document with a carrier element and a foil element arranged in a partial region of the carrier element. The carrier element has, at least in the partial region, a luminescence marker which is adapted to give off luminescence radiation which has at least a first wavelength and a second wavelength in each case in the infrared spectral region. The foil element has a reflection layer and a spectral selection layer. The selection layer is arranged between the carrier element and the reflection layer. The reflection layer is configured to reflect infrared radiation and the selection layer is configured to spectrally selectively inhibit transmission of infrared radiation. The inhibition of the transmission of the first wavelength and the inhibition of the transmission of the second wavelength differ by at least 10%.

Claims

1.-15. (canceled)

16. A value document with a carrier element and a foil element arranged in a partial region of the carrier element, wherein the carrier element has, at least in the partial region, a luminescence marker which is adapted to give off luminescence radiation which has at least a first wavelength and a second wavelength in each case in the infrared spectral region, and wherein the foil element has a reflection layer and a spectral selection layer, wherein the selection layer is arranged between the carrier element and the reflection layer, wherein the reflection layer is configured to reflect infrared radiation and the selection layer is configured to spectrally selectively inhibit transmission of infrared radiation, wherein the inhibition of the transmission of the first wavelength and the inhibition of the transmission of the second wavelength differ by at least 10%.

17. The value document according to claim 16, wherein the foil element is configured as a security element constructed in layered fashion.

18. The value document according to claim 16, wherein the foil element is configured as a patch and/or hologram and/or security thread and/or security strip.

19. The value document according to claim 16, wherein the foil element is applied to a surface of the carrier element.

20. The value document according to claim 16, wherein the reflection layer and the selection layer are configured to overlap when viewed perpendicular to the carrier element.

21. The value document according to claim 16, wherein the selection layer is configured as an absorption layer.

22. The value document according to claim 16, wherein the reflection layer has a reflection spectral region, and the selection layer has a selection spectral region, wherein the reflection spectral region is more broadband than the selection spectral region.

23. The value document according to claim 16, wherein the reflection layer is adapted to reflect at least 50% of a luminescence radiation irradiated by the luminescence marker and incident on the reflection layer.

24. The value document according to claim 16, wherein the luminescence marker is embedded in the carrier element.

25. The value document according to claim 16, wherein the value document has a document-class-specific spectral signature which is dependent on a luminescence radiation irradiated by the luminescence marker and incident on the selection layer.

26. A method for classifying a value document with a carrier element having a luminescence marker and a foil element arranged in a partial region of the carrier element and having a reflection layer, in which the following steps are performed: a) exciting the luminescence marker with radiation from an excitation side of the value document, the excitation side being the side of the value document facing away from the foil element; b) capturing an intensity of the infrared luminescence radiation irradiated by the excited luminescence marker and reflected by the reflection layer; c) comparing the captured intensity with a reference intensity; and d) classifying the value document based on the comparison.

27. The method according to claim 26, wherein the luminescence radiation irradiated by the excited luminescence marker is spectrally inhibited by a selection layer of the foil element before the capture in step b).

28. The method according to claim 26, wherein as the captured intensity, at least a first intensity of a first wavelength and a second intensity of a second wavelength each in the infrared spectral region are captured.

29. The method according to claim 26, wherein a direct luminescence intensity of the luminescence marker outside the partial region is captured on the direct way of propagation, and in step d) the classification is performed based on the direct luminescence intensity and the intensity captured in step b).

30. The method according to claim 26, wherein the reference intensity is made available by a direct luminescence intensity of the luminescence marker captured outside the partial region and on the direct way of propagation.

Description

[0050] Embodiment examples of the invention will hereinafter be discussed more closely with reference to a schematic drawing.

[0051] There are shown:

[0052] FIG. 1 a schematic diagram of an embodiment example of a value document according to the invention with a carrier element and a foil element, the carrier element having a luminescence marker;

[0053] FIG. 2 a schematic diagram of a further embodiment example of the value document, the luminescence marker being arranged on the side of the carrier element facing away from the foil element;

[0054] FIG. 3 a schematic diagram of a further embodiment example of the value document, the foil element being embedded in the carrier element;

[0055] FIG. 4 a schematic diagram of a further embodiment example of the value document, the luminescence marker being arranged on the side of the carrier element facing the foil element;

[0056] FIG. 5 a schematic diagram of a method for classifying a value document having a carrier element and a foil element;

[0057] FIG. 6 a schematic diagram of excitation radiation for exciting the luminescence marker and of luminescence radiation given off by the luminescence marker;

[0058] FIG. 7 a schematic diagram of a luminescence spectrum, an absorption spectral region and a spectral signature;

[0059] FIG. 8 a further schematic diagram of a luminescence spectrum, an absorption spectral region and a spectral signature;

[0060] FIG. 9 a schematic diagram of a luminescence spectrum, a selection spectral region configured as a band absorber filter and a spectral signature;

[0061] FIG. 10 a schematic diagram of a luminescence spectrum, a selection spectral region configured as a low-pass filter and a spectral signature; and

[0062] FIG. 11 a schematic diagram of a luminescence spectrum, a selection spectral region configured as a high-pass filter and a spectral signature.

[0063] In the figures, identical or functionally identical elements have the same reference signs.

[0064] FIG. 1 schematically shows an embodiment example of a value document 1. The value document 1 has a carrier element 2. The carrier element 2 in turn has a partial region 3.

[0065] In the partial region 3, a foil element 4 is arranged. Furthermore, the carrier element 2 has a luminescence marker 5 in the partial region 3. In particular, the luminescence marker 5 is configured as a plurality of particles, preferably in powder form.

[0066] The luminescence marker 5 is configured to give off luminescence radiation 6. The luminescence radiation 6 has at least a first wavelength 7 in the infrared spectral region and a second wavelength 8 in the infrared spectral region.

[0067] The luminescent substance used for the luminescent security marker or luminescence marker 5 can be, for example, organic, metalorganic or inorganic luminescent substances. The excitation of the luminescent substances is preferably in the visible or infrared spectral region. Particularly suitable are luminescent substances in which both excitation and emission are in the infrared spectral region, since here particularly low scattering losses and thus particularly high intensities occur in the backside measurement through the carrier element 2.

[0068] Examples of such luminescent substances are inorganic pigments doped with one or several rare earth elements, in particular with the dopants neodymium or ytterbium or erbium or thulium or holmium, or doped with certain transition metals. The combination of ytterbium with a further dopant, in particular erbium, thulium, neodymium or holmium, is preferred. Furthermore, metalorganic complexes, in particular with neodymium or holmium or erbium or thulium or ytterbium, or certain organic substances can be employed.

[0069] As luminescence marker 5, one single luminescent substance or a mixture or combination of several luminescent substances can be employed. In the latter case, the first and the second wavelength of luminescence emission may be emitted from the same luminescent substance or from different luminescent substances of the luminescence marker 5.

[0070] In addition to the luminescence marker 5, the value document 1 may comprise further feature substances which increase the forgery resistance, for example further luminescent substances. It is also possible to combine several luminescence markers 5 with different spectral signatures in the value document 1. For example, the luminescence marker 5 may be present as a mixture with the further feature substance, or the luminescence marker 5 and the further feature substance may be present at different locations of the value document 1, for example in the volume or on one or both surfaces of the value document 1.

[0071] The first wavelength 7 can be 1100 nm, for example. The second wavelength 8 can be 1600 nm, for example.

[0072] According to the embodiment example, the foil element 4 has a reflection layer 9 and a spectral selection layer 10. The selection layer 10 is here arranged between the carrier element 2 and the reflection layer 9. According to the embodiment example, the reflection layer 9 and the selection layer 10 are arranged parallel to each other.

[0073] The reflection layer 9 is configured to reflect infrared radiation, in particular the luminescence radiation 6.

[0074] The selection layer 10 is configured to spectrally selectively inhibit transmission of infrared radiation, in particular the luminescence radiation 6. The inhibition of transmission by the selection layer 10 at the first wavelength 7 is at least 10% more or less than the inhibition of transmission of the second wavelength 8, expressed in absolute percentage points. If the transmission through the selection layer 10 at the first wavelength 7 is for example 50%, the transmission through the selection layer 10 at the second wavelength 8 is preferably either at least 60% or at most 40%.

[0075] Preferably, the selection layer 10 is configured as a spectrally selective absorption layer. This means that the absorbing selection layer 10 absorbs at least partly certain wavelengths or wavelength regions. In particular, the selection layer 10 has an IR absorber.

[0076] For the IR absorber in the selection layer, for example inorganic, metalorganic or organic pigments or dyes are employed. Preferably, the absorber layer is printed on during the manufacture of the foil element. The IR absorber is then present in particular in the form of pigment particles or a dye embedded in a printing ink. Suitable inorganic pigments can be, for example, oxides, halides, phosphates, chalcogenides, vanadates, silicates or germanates of transition metals (e.g. Zn, Ti, V, Cr, Mn, Fe, Co, Ni, Cu) or rare earth elements (e.g. Ce, Pr, Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm, Yb). Suitable metalorganic compounds are e.g. phthalocyanines or naphthalocyanines. Suitable organic compounds are e.g. Cu H2Pc or porphyrins.

[0077] The construction of the value document 1 enables a measurement 11 in remission geometry. For this purpose, according to the embodiment example, the luminescence marker 5 is excited, for example by irradiation with light, in particular infrared light. The irradiation is effected in particular from a side 12 of the carrier element 2 facing away from the foil element 4.

[0078] The luminescence marker 5 gives off luminescence radiation 6 due to the excitation. The luminescence radiation 6 in turn propagates in the carrier element 2 and impinges at least partly on the selection layer 10. Only a part of the spectrum is allowed to pass through the selection layer 10 unhindered, or it may even be that the complete spectral region of the luminescence radiation 6 is inhibited, preferably to varying degrees with regard to intensity. The luminescence radiation 6, which has penetrated the selection layer 10 or emerges on the side of the selection layer 10 facing away from the carrier element 2, therefore has in particular a different spectral signature than before entering the selection layer 10.

[0079] The luminescence radiation, which is at least partly inhibited by the selection layer 10 or altered with regard to spectral intensities, now impinges on the reflection layer 9. The luminescence radiation 6 is reflected at least partly by the reflection layer 9 and at least partly passes through the selection layer 10 again. After passing through the selection layer 10, the luminescence radiation 6 passes through the carrier element 2 and can then be detected on the side 12 of the carrier element 2 facing away from the foil element 4. For detection, for example, a detector is arranged on the side 12 facing away.

[0080] It is possible that during the detection of the reflected luminescence signal or the reflected luminescence radiation 6 not only reflected luminescence radiation is captured, but in combined manner also a portion of directly radiated luminescence radiation.

[0081] According to the embodiment example, the foil element 4 is configured as a security element constructed in layered fashion. The security element is characterized in that it is difficult to reproduce without special manufacturing equipment and special manufacturing knowledge. Preferably, the foil element is configured as a hologram and/or security thread and/or security strip.

[0082] According to the embodiment example, the foil element 4 is arranged on a surface 13.

[0083] According to the embodiment example, the reflection layer 9 and the selection layer 10 are configured to overlap at least in certain regions when viewed perpendicularly to the carrier element 2. For example, the reflection layer 9 and the selection layer 10 are configured to overlap completely. For example, the reflection layer 9 and the selection layer 10 are configured on top of each other in exact register.

[0084] The reflection layer 9 has a reflection spectral region 14. The selection layer 10 has a selection spectral region 15. According to the embodiment example, the reflection spectral region 14 is configured to have more broadband than the selection spectral region 15. This means that the reflection spectral region 14 or the reflection layer 9 reflects a larger wavelength region than the selection spectral region 15 or the selection layer 10 inhibits. This is advantageous because it also allows broadband-reflective metal layers to be employed for the reflection layer, which can simultaneously make available other functions of the foil element, e.g. a reflection hologram.

[0085] FIG. 2 shows the value document 1 analogous to FIG. 1, but according to this embodiment example the luminescence marker 5 is arranged on the opposite side 12 of the carrier element 2. For example, the luminescence marker 5 can be printed on or applied as a backside coating to the carrier element 2.

[0086] Supplementary, the luminescence marker 5 can also be embedded in the carrier element 2 as shown in FIG. 1.

[0087] FIG. 3 shows the value document 1 also analogous to FIG. 1. However, according to the embodiment example of FIG. 3, the foil element 4 is embedded in the carrier element 2. This means, for example, that there is a recess 16 in the carrier element 2 in which the foil element 4 is incorporated or embedded or integrated. It is possible that the foil element 4 is worked into the carrier element 2 during manufacture of the carrier element. For example, the foil element 4 can be surrounded by the carrier element 2 merely on some sides or it can be completely surrounded by the carrier element 2 on all sides. This is particularly the case when the foil element 4 is designed as a fully embedded security thread or as a security thread partly embedded only in some regions of a so-called window thread.

[0088] The luminescence marker 5 is arranged in the carrier element 2 according to the embodiment example of FIG. 3. However, it is also possible that the luminescence marker 5 in the embodiment example of FIG. 3 is only arranged outside the carrier element 2, for example as shown in FIG. 2, at the carrier element 2. Furthermore, it is also possible that the luminescence marker is both embedded in the carrier element 2 and at the same time applied to an outer side of the carrier element 2.

[0089] FIG. 4 shows a further embodiment example of the value document 1 analogous to FIG. 1. However, according to the embodiment example of FIG. 4, the luminescence marker 5 is located on the surface 13 of the carrier element 2 between the foil element 4 and the carrier element 2. In addition, the luminescence marker 5 can also be configured in the carrier element 2.

[0090] FIG. 5 shows an embodiment example of a method for classifying the value document 1. An excitation unit 17 is shown, which excites the luminescence marker 5 with excitation radiation 26, for example light. The excited luminescence marker 5 gives off luminescence radiation 6 after the excitation operation. According to the embodiment example, the luminescence radiation 6 is given off at least with the first wavelength 7 and the second wavelength 8.

[0091] At least a part of the luminescence radiation 6 impinges on the selection layer 10, which is optionally present in the method and is not shown in the Figure, and is at least partly spectrally inhibited there, i.e. intensities of selected wavelengths of the luminescence radiation 6 are reduced or emerge from the selection layer 10 with less intensity than they enter into the selection layer 10. After the selection layer 10, the at least partly inhibited or with respect to the spectral intensities altered luminescence radiation 6 impinges on the reflection layer 9 and is thrown back from there to the selection layer 10, i.e. is reflected, penetrates the selection layer 10 again, now also penetrates the carrier element 2 and is finally captured outside the carrier element 2, on the facing-away side 12 of the carrier element 2 by a capture unit 18. The capture unit 18 here is configured, for example, as a spectrometer and/or has at least two capture units. Preferably, a first capture unit is configured to capture the first wavelength 7, but not the second wavelength 8, and a second capture unit is configured to capture the second wavelength 8, but not the first wavelength 7. The capture region on the value document 1 is preferably smaller than the extent of the foil element 4. The first capture unit and the second capture unit preferably have substantially the same capture region.

[0092] FIG. 6 shows a schematic diagram of an embodiment example of the method in which an excitation radiation 26 for exciting the luminescence marker 5 is irradiated in the direction of the carrier element 2. The excitation radiation 26 preferably has only one single wavelength. After excitation of the luminescence marker 5, the excitation radiation 26 continues to radiate with reduced intensity, in the embodiment example penetrates the selection layer 10 and impinges on the reflection layer 9. The excitation radiation 26 is reflected by the reflection layer 9, is radiated again through the selection layer 10 and impinges on the luminescence marker 5 again to excite it anew with decreased intensity. After the re-excitation, the excitation radiation 26 then leaves the carrier element 2 with an again decreased intensity on the side 12 facing away from the foil element 4.

[0093] Furthermore, the first wavelength 7 of the luminescence radiation 6 is shown, which is emitted by the luminescence marker 5 after excitation in particular in all spatial directions. The luminescence radiation emitted at the first wavelength 7 in the direction of the foil element penetrates the carrier element 2 and the selection layer 10 substantially uninhibited. Subsequently, the first wavelength 7 is reflected at the reflection layer 9 and again penetrates the selection layer 10 substantially uninhibited. Furthermore, the first wavelength 7 also penetrates the carrier element 2 and can be captured on the side 12 facing away from the foil element 4.

[0094] However, the first wavelength 7 radiates in particular in an undirected manner, for the reason of which the first wavelength 7 emerges from the carrier element uninhibited on the facing-away side 12 even without passing through the selection layer 10.

[0095] In addition, the second wavelength 8 is also shown, which is also emitted by the luminescence marker 5 after excitation in particular in all spatial directions. The luminescence radiation emitted at the second wavelength 8 in the direction of the foil element penetrates the carrier element 2 uninhibited and impinges on the selection layer 10. According to the embodiment example, the selection layer 10 is configured to inhibit the second wavelength 8, i.e. the second wavelength 8 leaves the selection layer 10 weakened or with less intensity than before entering the selection layer 10. At the reflection layer 9, the second wavelength 8 is also reflected back to the selection layer 10 and passes through the selection layer 10 again, the second wavelength 8 being further diminished when passing through the selection layer 10 again. Subsequently, the second wavelength 8 penetrates the carrier element 2 and leaves it at the facing-away side 12.

[0096] The second wavelength 8 also radiates in particular in an undirected manner, for the reason of which the second wavelength 8 emerges from the carrier element uninhibited on the facing-away side 12 even without passing through the selection layer 10.

[0097] FIG. 7 shows an embodiment example of a document-class-specific spectral signature 19. It can be seen that the spectral signature 19 has a dent 20. The dent 20 arises, for example, at the location of the second wavelength 8. The dent 20 arises by the selection layer 10 inhibiting the intensity of the second wavelengths 8.

[0098] Compared to the spectral signature 19, a normal curve 22 and an absorptionless curve 23 are shown. The normal curve 22 arises when the reflection layer 9 is not present and only the direct luminescence radiation of the luminescence marker 5 is captured, for example outside the partial region 3. The absorptionless curve 23 arises when no selection layer 10 is present and thus there is no selective inhibition, but the reflection layer 9 is present, for example in the case of a forged foil element. The dent 20 is then not present in the latter case.

[0099] On an abscissa 24 of the diagrams of FIGS. 6 to 11, the wavelength is plotted in nm. On an ordinate 25 of the diagrams, the signal strength is plotted, for example in units of the photocurrent of a photodiode.

[0100] FIG. 8 shows an embodiment example of a spectral signature 19. The spectral signature 19 is formed by the selection spectral region 15, in particular absorption spectral region or absorption spectrum, and a luminescence spectrum 27 or emission spectrum of the luminescence marker 5. In this embodiment example, the luminescence spectrum 27 has two spectral bands. These spectral bands can, for example, be emitted by two different luminescent substances which together form the luminescence marker 5. The luminescence spectrum 27 may correspond to the normal curve 22 of FIG. 7.

[0101] FIG. 9 shows a further embodiment example in a schematic diagram of the spectral signature 19. The spectral signature 19 is formed by the luminescence spectrum 27 and selection spectral region 15 configured in narrow-band fashion.

[0102] FIG. 10 shows a further embodiment example in a schematic diagram of the spectral signature 19. The spectral signature 19 is formed by the luminescence spectrum 27 and the selection spectral region 15 configured as a low-pass filter.

[0103] FIG. 11 shows a further embodiment example in a schematic diagram of the spectral signature 19. The spectral signature 19 is formed by the luminescence spectrum 27 and the selection spectral region 15 configured as a high-pass filter.

[0104] In another embodiment example, a value document 1 is manufactured. A carrier element 2 made of paper is provided over its full area with a luminescence marker 5 which consists of two luminescent substances which are both excitable at the same wavelength or the same excitation radiation 26, and wherein the first luminescent substance emits luminescence radiation 6 at 1100 nm—corresponding to the first wavelength 7—and the second luminescent substance emits luminescence radiation at 1600 nm—corresponding to the second wavelength 8. To this carrier element 2, a security strip is additionally applied on the front side 13 in a partial region 3 as a foil element 4. The security strip has a visual level 1 feature which consists of a microlens structure with an underlying printed white ink layer. The white ink layer at the same time serves as a reflection layer 9. In addition, the foil element 4 has, underneath the white ink layer, an IR absorber layer as a selection layer 10. In this embodiment example, the IR absorber layer is made of a security printing ink with absorption varying over a broad bandwidth, which at 1100 has an absolute absorption of approx. 50% nm and at 1600 nm an absolute absorption of only 10%. The construction of the value document corresponds to FIG. 1, the spectral ratios to FIG. 11.

[0105] The value document 1 is manipulated, for example, by removing the foil element 4 and replacing it with a piece of aluminum foil for a simple impression forgery. The forged foil element differs from the authentic foil element 4 in particular in that it does not have a selection layer 10.

[0106] For the authenticity check according to FIG. 5 and FIG. 6, a sensor in remission geometry is used, which in particular has at least one excitation unit 17 and a capture unit 18. The value document 1 is transported past the sensor by a transport device, whereby at least one measurement of the luminescence radiation 6 is carried out by the sensor in the partial region 3, and at least one further measurement of the luminescence radiation 6 is carried out outside the partial region 3. For this purpose, the value document 1 is illuminated with excitation radiation 26 which is adapted to excite both luminescent substances of the luminescence marker 5 to luminescent emission. The luminescence radiation 6 emerging from the backside 12 of the value document 1 is captured by the capture unit 18, a first capture unit capturing only the luminescence intensity at 1100 nm and a second capture unit capturing only the luminescence intensity at 1600 nm. When viewed from the sensor behind the document transported past, there is a broadband-absorbing, for example black, area.

[0107] By the presence of the luminescence radiation 6 at the first wavelength 7, in particular 1100 nm, and at the second wavelength 8, in particular 1600 nm, the authenticity of the carrier element 2 is proven. The captured intensities of the luminescence radiation 6 at the first wavelength 7 and the second wavelength 8 are in particular in a fixed ratio characteristic for the luminescence marker 5, which ratio is ascertained in the measurement outside the partial region 3 or is measured there (luminescence spectrum 27 in FIG. 11). In the present embodiment example, this ratio is preferably 1.0.

[0108] In the measurements in the partial region 3, the luminescence intensities or intensities measured are significantly higher due to the influence of the reflection layer 9 of the foil element 4. For example, in the presence of a foil element with a reflection layer 9, the measured intensities at the wavelengths 7 and 8 are increased by about 50%.

[0109] If the foil element has the IR absorber layer 10 characteristic of an authentic foil element 4, the measured intensity at the first wavelength 7, in particular 1100 nm, is, due to the interaction with this selection layer, however about 10% lower than at the second wavelength 8, in particular 1600 nm, which is in particular characteristic of the spectral signature 19. The authenticity of the foil element 4 can thus be checked on the basis of the measured ratio between the luminescence intensity at the first wavelength 7 and the luminescence intensity at the second wavelength 8. As a decision criterion, the difference in intensity ratios outside partial region 3 and in the partial region 3 is used. If the measured intensity ratio in the partial region 3 is, for example, more than 0.07 smaller than outside the partial region 3, the existence and the authenticity of the foil element 4 is considered confirmed, otherwise the checked value document 1 is rejected.