SECURITY ELEMENT

Abstract

A security transfer element includes a security element layer composite with a functional layer arranged to develop an optically variable effect for a viewer. On the opposite side of the functional layer with respect to the viewer, the security element layer composite has at least one luminescent substance. The luminescent substance has a primary emission wavelength and can be excited by an excitation radiation. The functional layer is configured to be opaque to the emission radiation of the luminescent substance. The security transfer element comprises a carrier film, and the security element layer composite is arranged on the carrier film in a detachable manner. The security element layer composite comprises a functional layer and an adhesive layer. The functional layer has an embossing lacquer with an embossed structure. The embossing lacquer is coated with a metallization. The adhesive layer comprises several luminescent substances.

Claims

1.-32. (canceled)

33. A security transfer element for a value document, comprising a security element layer composite and a carrier film detachably connected to the security element layer composite, wherein the security element layer composite has a functional layer which, after being transferred to a value document, develops an optically variable effect for a viewer; has an adhesive layer; has an upper side which, after the security element layer composite has been transferred to a value document substrate, faces the viewer, wherein the adhesive layer is arranged on the side of the functional layer which lies opposite the upper side; and has at least one luminescent substance, wherein the luminescent substance is arranged in the adhesive layer and/or in a luminescent substance layer, wherein the adhesive layer and/or the luminescent substance layer is arranged on the side of the functional layer in the security element layer composite which is opposite the upper side; wherein the luminescent substance has a primary emission radiation in the wavelength range between 700 nm and 2100 nm and can be excited by an excitation radiation in the wavelength range between 400 nm and 2100 nm; and the functional layer is configured to be opaque to the emission radiation of the luminescent substance.

34. The security transfer element according to claim 32, wherein the emission radiation of the luminescent substance of the security element layer composite lies in a wavelength range between 900 nm and 1300 nm, and/or 1300 nm and 1600 nm, and/or 1600 nm and 1850 nm and/or 1850 and 2100 nm.

35. The security transfer element according to claim 33, wherein the luminescent substance of the security element layer composite does not have any additional anti-Stokes emission that can be visually recognized by humans.

36. The security transfer element according to claim 33, wherein the luminescent substance of the security element layer composite comprises organic dyes, organometallic complexes with in erbium, thulium, holmium, neodymium or ytterbium, and/or doped inorganic pigments with the dopants erbium, thulium, holmium, neodymium or ytterbium or doped with transition metals including chromium, manganese and/or iron.

37. The security transfer element according to claim 33, wherein the at least one luminescent substance has a grain size (D99) of less than 15 m.

38. The security transfer element according to claim 33, wherein the functional layer is configured to be absorbent and/or reflective.

39. The security transfer element according to claim 33, wherein the functional layer comprises a metallic layer and/or a metallic coating at least in certain regions, wherein the metallic layer and/or the metallic coating is configured on the side of the functional layer which faces away from the viewer or is configured on the side of the functional layer which faces the viewer.

40. The security transfer element according to claim 33, wherein the functional layer developing the optically variable effect comprises a reflective embossed structure, in a diffractive structure and/or a reflective microstructure, and/or has transparent highly refractive layers, thin-film elements with a color shift effect, with a reflective layer and a semitransparent layer and a dielectric layer arranged in between, layers of liquid crystalline material, of cholesteric liquid crystalline material, printing layers based on effect pigment compositions with viewing angle-dependent effect or with different colors and/or a multilayer structure, namely two semitransparent layers and a dielectric layer arranged between the two semitransparent layers.

41. The security transfer element according to claim 33, wherein the security element layer composite has a scattering layer with light-scattering properties, wherein the scattering layer is arranged adjacent to the luminescent substance and/or is arranged adjacent to the luminescent substance layer; and/or is part of the functional layer.

42. A value document comprising an areal value document substrate and a security element layer composite, wherein the security element layer composite has a functional layer which, when viewed in incident light onto an upper side of the functional layer, develops an optically variable effect for a viewer; has an adhesive layer; has an upper side which, after the security element layer composite has been transferred to a value document substrate, faces the viewer, wherein the adhesive layer is arranged on the side of the functional layer which lies opposite the upper side; and has at least one first luminescent substance, wherein the first luminescent substance is arranged in the adhesive layer and/or in a luminescent substance layer which is arranged on the side of the functional layer opposite the upper side in the security element layer composite; and the security element layer composite is arranged on an upper side of the value document substrate in such a manner that the functional layer developing the optically variable effect is aligned such that the optically variable effect can be recognized in incident light onto an upper side of the value document and the security element layer composite in incident light onto a lower side of the value document which lies opposite the upper side of the value document is covered at least in certain regions by the value document substrate; wherein the at least one first luminescent substance has a primary emission radiation in the wavelength range between 700 nm and 2100 nm and can be excited by an excitation radiation in the wavelength range between 400 nm and 2100 nm; and the functional layer is configured to be opaque to the emission radiation of the luminescent substance.

43. The value document according to claim 42, wherein the intensity of the emission radiation of the at least one first luminescent substance of the security element layer composite is significantly higher on the lower side than on the upper side of the value document, wherein no emission radiation of the first luminescent substance exits on the upper side.

44. The value document according to claim 42, wherein the value document substrate has at least one second luminescent substance.

45. The value document according to claim 42, wherein the emission radiation of the first luminescent substance of the security element layer composite lies in a wavelength range between 900 nm and 1300 nm and/or 1300 nm and 1600 nm, and/or 1600 nm and 1850 nm and/or 1850 and 2100 nm.

46. The value document according to claim 42, wherein the first luminescent substance of the security element layer composite has no additional anti-Stokes emission that can be visually recognized by humans.

47. The value document according to claim 42, wherein the first luminescent substance of the security element layer composite and/or the second luminescent substance of the value document substrate comprises organic dyes, organometallic complexes with erbium, thulium, holmium, neodymium or ytterbium, and/or doped inorganic pigments with the dopants erbium, thulium, holmium, neodymium or ytterbium or doped with transition metals, including chromium, manganese and/or iron.

48. The value document according to claim 42, wherein the at least one first luminescent substance of the security element layer composite and/or the at least one second luminescent substance of the value document substrate has a grain size (D99) of less than 15 m.

49. The value document according to claim 42, wherein the functional layer is configured to be absorbent and/or reflective, in relation to the emission radiation of the first luminescent substance.

50. The value document according to claim 42, wherein the functional layer comprises at least in certain regions, a metallic layer and/or a metallic coating, wherein the metallic layer and/or the metallic coating is configured to be on the side of the functional layer which faces away from the viewer.

51. The value document according to claim 42, wherein the functional layer developing the optically variable effect comprises a reflective embossed structure, in a diffractive structure and/or a reflective microstructure, and/or has transparent highly refractive layers, thin-film elements with a color shift effect, with a reflective layer and a semitransparent layer and a dielectric layer arranged in between, layers of liquid crystalline material, of cholesteric liquid crystalline material, printing layers based on effect pigment compositions with viewing angle-dependent effect or with different colors and/or a multilayer structure, namely two semitransparent layers and a dielectric layer arranged between the two semitransparent layers.

52. The value document according to claim 42, wherein the security element layer composite has a scattering layer with light-scattering properties, wherein the scattering layer is arranged adjacent to the first luminescent substance and/or is arranged adjacent to the luminescent substance layer; and/or is part of the functional layer.

53. The value document according to claim 42, wherein the intensity of the emission radiation of the at least one first luminescent substance in incident light onto the lower side of the value document is more than 50% higher than in incident light onto the upper side of the value document.

54. The value document according to claim 42, wherein the value document substrate comprises at least one layer of a paper substrate layer, wherein the paper substrate layer comprises cellulose fibers and/or fillers, wherein the fillers are titanium dioxide, organic aids, carboxymethyl cellulose, and/or comprises at least one plastic layer, and/or the value document substrate has a Kubelka-Munk scatter coefficient with a value between 10 and 80 l/mm in a wavelength range from 400 nm to 2100 nm.

55. The value document according to claim 42, wherein the value document substrate comprises at least one second luminescent substance, wherein the emission wavelength range of the emission radiation and/or excitation wavelength range of the second luminescent substance corresponds substantially the wavelength range of the emission radiation and/or excitation of the first luminescent substance of the security element layer composite, wherein the first luminescent substance of the security element layer composite and the second luminescent substance of the value document substrate have a mutually complementary luminescence behavior.

56. The value document according to claim 42, wherein the first luminescent substance has a refractive index which is matched to the refractive index of the material surrounding the first luminescent substance, wherein the refractive index of the first luminescent substance is equal to the refractive index of the material surrounding the first luminescent substance.

57. A method for checking a value document according to claim 42, having the following steps of: applying to the value document an excitation radiation in incident light onto the lower side of the value document, wherein the excitation radiation comprises the wavelength range for excitation of the first luminescent substance of the security element layer composite; detecting an emission, in a rise and/or a decay behavior of the emission radiation, of the first luminescent substance of the security element layer composite on the lower side of the value document over at least one areal region of the value document; and ascertaining the authenticity of the security element layer composite from the detected emission, from the rise and/or decay behavior of the detected emission radiation.

58. The method according to claim 57, wherein the areal region of the value document comprises the region of the security element layer composite and a region surrounding the security element layer composite which has an area of at least 100% of the area of the security element layer composite.

59. The method according to claim 57, wherein the detected emission, in the detected rise behavior and/or the detected decay behavior, results in a two-dimensional pattern over the areal region, and the pattern corresponds to the type of security element layer composite.

60. The method according to claim 57, wherein the further steps of: applying to the value document an excitation radiation in incident light onto the upper side of the value document, wherein the excitation radiation comprises the wavelength range for excitation of the first luminescent substance of the security element layer composite; detecting an emission, in a rise and/or a decay behavior of the emission radiation, of the first luminescent substance of the security element layer composite on the upper side of the value document over at least one areal region of the value document; and comparing the emission detected on the upper side of the value document with the emission detected on the lower side of the value document for checking the authenticity of the value document.

61. A checking unit for checking value documents, with an excitation device for applying to the respective value document an excitation radiation in incident light onto the lower side of the value document, wherein the excitation radiation comprises the wavelength range for excitation of the first luminescent substance of the security element layer composite of the value document; a detection device for detecting an emission, in a rise and/or a decay behavior of the emission radiation, of the first luminescent substance of the security element layer composite on the lower side of the respective value document over at least one areal region of the respective value document; and an evaluation device for checking the authenticity of the respective value document based on the detected emission, based on the rise and/or decay behavior of the detected emission radiation, wherein the checking unit is configured to carry out the method according to claim 57.

62. A value document processing apparatus for checking value documents, comprising an interface for feeding value documents, at least one checking unit according to claim 61 for checking the value documents and an output unit for outputting the value documents.

63. A system comprising: a checking unit and/or a value document processing apparatus according to claim 62; and a security transfer element comprising a security element layer composite and a carrier film detachably connected to the security element layer composite, wherein the security element layer composite has a functional layer which, after being transferred to a value document, develops an optically variable effect for a viewer; has an adhesive layer; has an upper side which, after the security element layer composite has been transferred to a value document substrate, faces the viewer, wherein the adhesive layer is arranged on the side of the functional layer which lies opposite the upper side; and has at least one luminescent substance, wherein the luminescent substance is arranged in the adhesive layer and/or in a luminescent substance layer, wherein the adhesive layer and/or the luminescent substance layer is arranged on the side of the functional layer in the security element layer composite which is opposite the upper side; wherein the luminescent substance has a primary emission radiation in the wavelength range between 700 nm and 2100 nm and can be excited by an excitation radiation in the wavelength range between 400 nm and 2100 nm; and the functional layer is configured to be opaque to the emission radiation of the luminescent substance; and/or a value document comprising: an areal value document substrate and a security element layer composite, wherein the security element layer composite has a functional layer which, when viewed in incident light onto an upper side of the functional layer, develops an optically variable effect for a viewer; has an adhesive layer; has an upper side which, after the security element layer composite has been transferred to a value document substrate, faces the viewer, wherein the adhesive layer is arranged on the side of the functional layer which lies opposite the upper side; and has at least one first luminescent substance, wherein the first luminescent substance is arranged in the adhesive layer and/or in a luminescent substance layer which is arranged on the side of the functional layer opposite the upper side in the security element layer composite; wherein the security element layer composite is arranged on an upper side of the value document substrate in such a manner that the functional layer developing the optically variable effect is aligned such that the optically variable effect can be recognized in incident light onto an upper side of the value document and the security element layer composite in incident light onto a lower side of the value document which lies opposite the upper side of the value document is covered at least in certain regions by the value document substrate; wherein the at least one first luminescent substance has a primary emission radiation in the wavelength range between 700 nm and 2100 nm and can be excited by an excitation radiation in the wavelength range between 400 nm and 2100 nm; and the functional layer is configured to be opaque to the emission radiation of the luminescent substance.

64. A method for checking a value document, wherein the value document has a value document substrate and a security element, and the security element has an optically variable effect for a viewer in incident light onto an upper side of the value document at least in certain regions, and the value document has at least one luminescent sub stance, wherein the luminescent substance has a primary emission radiation in the wavelength range between 700 nm and 2100 nm and is arranged to be excited by an excitation radiation in the wavelength range between 400 nm and 2100 nm; wherein the security element partially or completely covers the luminescent substance in incident light onto the upper side of the value document, wherein the value document is configured so that emission radiation from the luminescent substance to the upper side of the value document in the regions in which the security element in incident light onto the upper side the value document covers the luminescent substance is hindered; with the steps of: applying to the value document an excitation radiation in incident light onto a lower side of the value document, wherein the excitation radiation comprises the wavelength range for excitation of the luminescent substance of the value document; detecting an emission, in a rise and/or a decay behavior of the emission radiation, of the luminescent substance on the lower side of the value document over at least one areal region of the value document; and ascertaining the authenticity of the value document from the detected emission, from the rise and/or decay behavior.

Description

[0175] The invention will hereinafter be explained further by way of example with reference to the drawings. There are shown:

[0176] FIGS. 1 a, b schematic and exemplary representations of a security transfer element according to the invention;

[0177] FIGS. 2 a-d a schematic view of a structure of a value document according to the invention; and

[0178] FIGS. 3 a, b a schematic representation of a checking method of a value document according to the invention.

[0179] In the embodiment examples, several (first) luminescent substances in the security element layer composite or, optionally, several (second) luminescent substances in the value document substrate are described. It goes without saying that also only one luminescent substance can be arranged in the security element layer composite or, optionally, in the value document substrate.

[0180] FIGS. 1a and 1b each show schematically an embodiment example of a security transfer element according to the invention. A security transfer element 20 in the form of a security strip is represented in FIG. 1a. The security transfer element 20 comprises a carrier film 21 of PET, for example. A security element layer composite 200 is detachably arranged on the carrier film 21. The security element layer composite 200 comprises a functional layer 210 and an adhesive layer 220. The functional layer 210 has an embossing lacquer 211 with an embossed structure 212, wherein the side of the embossing lacquer 211 which is not supplied with the embossed structure 212 faces the carrier film 21. The embossing lacquer 211 is coated on the side of the embossed structure 212 with a metallization 213, for example an aluminum layer. The metallization 213 matches to the shape of the embossing lacquer 211 and thus the embossed structure 212. The adhesive layer 220 is also arranged on the metalization 213. The adhesive layer 220 comprises several first luminescent substances.

[0181] In FIG. 1b a further security transfer element 20 according to the invention is represented and is constructed similarly to the security transfer element 20 from FIG. 1a. For the sake of simplicity and ease of understanding, the differences are substantially discussed. Identical and similar features are supplied with the same reference symbols for better understanding. The security transfer element 20 likewise has a carrier film 21 which is detachably connected to a security element layer composite 200. The security element layer composite 200 comprises an embossing lacquer 211 with an embossed structure 212, a metallization 213 which is arranged on the side of the embossing lacquer 211 which lies opposite the carrier film 21, and a luminescent substance layer 214 in which first luminescent substances are arranged. An adhesive layer 220 is arranged on the luminescent substance layer 214.

[0182] The security transfer element 20 of FIGS. 1a and 1b can be applied to a value document substrate (cf. FIGS. 2 a-d). For this purpose, the security transfer element 20 is placed on the value document substrate and connected to the value document substrate with the aid of activation of the adhesive layer 220. The carrier film 21 detachably connected to the security element layer composite 200 is removed subsequently. Merely the security element layer composite 200 remains on the value document substrate. The security element layer composite 200 is then arranged on the value document in such a manner that a viewer can perceive the embossed structure 212 in incident light onto the security element layer composite 200 (upper side) in such a manner that he can perceive an optically variable effect when changing the viewing angle. The metallization 213 serves as a reflector.

[0183] If the first luminescent substances of the luminescent substance layer 214 or the adhesive layer 220 are excited, their emission radiation is reflected by the metallization 213 in a direction which is not directed towards the upper side of the value document but towards the substrate. Emission radiation from the first luminescent substances can be detected only from the lower side of the value document.

[0184] The embossing lacquer 211, the metallization 213 and/or the luminescent substance layer 214 do not have to extend over the entire security transfer element 20. Rather, it is also conceivable that each of the layers is only applied in certain regions. In the examples of FIGS. 1a and 1b, the functional layer 200 has a recess.

[0185] FIGS. 2a to 2d represent exemplary and schematic embodiments of a value document 30 according to the invention.

[0186] In a first variant according to FIG. 2a, a value document 30 has a value document substrate 300. The value document substrate 300 comprises a value document substrate layer 320, which is printed with a printing layer 330, which in the present example is a printing ink layer 330. A security element layer composite 200 is arranged on the upper side of the value document substrate 300, namely on the printing ink layer 330. The security element layer composite 200 is thus separated from the value document substrate 300 by the printing ink layer 330. The side of the value document substrate 300 on which the security element layer composite 200 faces a viewer is the upper side of the value document 30.

[0187] The security element layer composite 200 is configured, for example, as represented in FIGS. 1a or 1b. The security element layer composite 200 comprises a functional layer and first luminescent substances. The functional layer is configured in such a manner that emission radiation of the first luminescent substances does not exit at the upper side of the value document 30. Rather, the emission radiation of excited first luminescent substances penetrates through the printing ink layer 330 and the value document substrate layer 320 and exits from the lower side of the value document 30.

[0188] To detect the luminescent substances of the security element layer composite 200, i.e. to detect the first luminescent substances, an excitation radiation must first traverse the value document substrate 300. The emission radiation of the excited first luminescent substances must then likewise traverse the value document substrate 300 in the opposite direction. As a result, the luminescence can, among other things, can be considerably weakened by scattering in the value document substrate 300 and absorption by the printing ink layer 330.

[0189] A value document 30 according to the invention is represented in FIG. 2b. The value document from FIG. 2b differs from the value document 30 from FIG. 2a in that the printing ink layer 330 is not merely applied to the value document substrate layer 320. In the embodiment example of FIG. 2b, the printing ink layer 330 is not part of the value document substrate 300. The security element layer composite 200 is arranged directly on the value document substrate 300. On the value document substrate 300 and the security element layer composite 200, the printing layer 330 is applied after the security element layer composite 200 has been arranged on the value document substrate 300 and thus also covers the security element layer composite 200, but not the connection area between the security element layer composite 200 and value document substrate 300. Instead of or in addition to the printing layer 330, an ink layer and/or lacquer layer and/or foil can be arranged.

[0190] The excitation radiation of the first luminescent substances in the security element layer composite 200 accordingly only has to penetrate through the value document substrate 300 in order to excite the first luminescent substances, and not the printing layer 330. Further, emission radiation from the first luminescent substances only needs to penetrate through the value document substrate 300 in order to be detected by a detector on the lower side of the value document 30, and not the printing layer 330.

[0191] The security element layer composite 200 can be executed as represented in FIGS. 1a and 1b. However, emission radiation from the first luminescent substances does not penetrate through the security element layer composite 200 in such a manner that the emission radiation exits from the upper side of the value document 30 and can be detected.

[0192] FIG. 2c shows a value document which is similar to the value document from FIG. 2b. In contrast, the printing layer 330 has a recess on the upper side of the value document substrate 300 in the region of the security element layer composite 200. A printing layer 330 is likewise arranged on the lower side of the value document substrate 300, which in transmitted light partially overlaps with the security element layer composite 200. Emission radiation and excitation radiation of the first luminescent substances must therefore penetrate through the printing layer 330 and the value document substrate layer 320 in certain regions. The printing layer 330 can accordingly weaken the excitation and emission of the first luminescent substances.

[0193] FIG. 2d shows a value document which is similar to that from FIG. 2c. In contrast, the value document substrate 300 has a thinning, so that after the security element layer composite 200 has been applied, the maximum thickness of the value document 30 does not increase too much. The thinning can substantially correspond to the thickness of the security element layer composite 200. Further, the region of the lower side of the value document which overlaps with the security element layer composite 200 in transmitted light was not printed in addition. Here, the excitation and emission radiation of the first luminescent substances only has to traverse the thin value document substrate 300 and not a printing layer 330, so that in this case the highest luminescence intensity can be achieved.

[0194] In the security element layer composite 200, viewed from the upper side of the value document 30, the first luminescent substance is located, preferably in one or several polymer layers below a reflective layer. Due to the strong absorption or reflection of the reflective layer, a reading out of the security element layer composite 200 from the upper side of the value document 30 is prevented on the one hand. On the other hand, an increase in the intensity of the first luminescent substances can be produced by the reflection of the excitation and emission radiation on its lower side, since e.g. scattered excitation radiation can thus impinge on the first luminescent substances several times.

[0195] FIGS. 3a and 3b show schematic representations of a checking method for a value document according to the invention. The checking of a value document 30 is represented here, which comprises a security element layer composite 200 which is arranged on a value document substrate 300. The security element layer composite 200 has an embossing lacquer layer 211 on which a reflective metallization 213 is applied. A luminescent substance layer 214 with first luminescent substances 240 is arranged below the embossing lacquer layer 211. The value document substrate 300 comprises a value document substrate layer 320, on which a printing layer 330 is applied on both sides.

[0196] The detection of the luminescence of the security element layer composite 200 or of the first luminescent substances 240 contained in the security element layer composite 200 is not carried out in the present case from the upper side of the value document 30, but from its lower side. An excitation radiation 410 from a sensor 50 passes through the printing layer 330, the value document substrate layer 320, again a further printing layer 330, part of the security element layer composite 200 and reaches the luminescent substance layer 214, which contains the first luminescent substances 240, stimulating these. Further, the excitation radiation 410 passes another part of the security element layer composite 200, reaches the metallization 213 and is reflected back (or scattered) there, so that the excitation radiation 410 cannot penetrate through the security element layer composite 200 and exit at the upper side.

[0197] Through multiple scattering and reflection, it is thus possible for the excitation radiation 410 to pass the part of the security element layer composite 200 containing the first luminescent substances 240 multiple times, whereby the metallization 213, if configured correspondingly, makes an important contribution to increasing the luminescence intensity of the security element layer composite 200. This contribution of the excitation radiation 410 at the value document substrate layer 320, for example, obtained through multiple scattering and/or reflection, is symbolized here schematically by the arrows 440.

[0198] The emission radiation 430 of the first luminescent substances 240 is generally emitted in undirected manner in all spatial directions. The luminescent substances 240 excited to luminescence therefore send back part of the emission radiation 430 directly (it thus passes the same path as the excitation radiation 410). However, a considerably larger part only reaches the sensor 50 only after several scattering or reflection processes. For example, a further part of the emission radiation 430 reaches the metallization 214 and is reflected (or scattered) on it and can thus likewise contribute to the detected emission radiation 430, which exits on the side of the value document 30 that does not carry the security element layer composite 200, here at the lower printing layer 330. The emission radiation 430 reaches sensor 50, which detects it.

[0199] The intensity of the emission radiation 430 detected at the sensor 50 is therefore most highly dependent on various factors: [0200] the structure of the security element layer composite 200 (e.g. distance between first luminescent substances 240 and the metallization 214), [0201] the scattering behavior of the individual layers, [0202] the structure of the metallization 214 (alignment and mattedness of the reflective metal areas, the scattering behavior of the value document substrate layer 320, etc.).

[0203] FIG. 3b shows the same value document 30 as in FIG. 3a, but here the measurement is carried out from the other side of value document 30. The excitation radiation 410 cannot penetrate through the metallization 214, so the luminescent substances 240 are not excited and do not emit any emission radiation.

[0204] In the application case, it is possible that a small portion of the excitation radiation 410 traverses the metallization 214, e.g. because said metallization is not completely reflective, and the luminescent substances 240 are thus partially excited. However, the resulting emission radiation would have to penetrate through the metallization 214 again, so that it is greatly weakened once more. The emission radiation detectable by the sensor 50 would therefore be very low.