Layer-Type Value Document Comprising an Ink Mixture in One Layer

• US 20090008926A1
• Filed: 04/05/2005
• Published: 01/08/2009
• Est. Priority Date: 05/05/2004
• Status: Active Grant

• Current Assignee: Giesecke & Devrient (Giesecke & Devrient GmbH)
• Original Assignee: Giesecke & Devrient GmbH
• Inventors: Mayer, Karlheinz, Baldus, Christof, Depta, Georg, Schiffmann, Peter
• Granted Patent: US 8,936,846 B2
• Time in Patent Office: Days
• US Class Current: 283/94
• CPC Class Codes: B42D 2033/20 Coloured material; Pigments or inks
• CPC Class Codes: B42D 2035/24 Colours
• CPC Class Codes: B42D 2035/44 Miniaturised markings
• CPC Class Codes: B42D 25/29 Securities; Bank notes
• CPC Class Codes: B42D 25/351 Translucent or partly translucent parts, e.g. windows
• CPC Class Codes: B42D 25/364 Liquid crystals
• CPC Class Codes: B42D 25/373 Metallic materials
• CPC Class Codes: B42D 25/378 Special inks
• CPC Class Codes: B42D 25/382 absorbing or reflecting infrared light
• CPC Class Codes: B42D 25/387 absorbing or reflecting ultraviolet light
• CPC Class Codes: B42D 25/41 using electromagnetic radiation B42D25/435 takes precedence
• CPC Class Codes: B42D 25/43 by removal of material
• CPC Class Codes: B42D 25/435 using electromagnetic radiation, e.g. laser
• CPC Class Codes: Y10T 428/24876 Intermediate layer contains particulate material [e.g., pigment, etc.]

Abstract

The invention relates to a value document, especially a banknote, having a sequence of layers into which visually and/or mechanically perceptible identifiers in the form of patterns, letters, numbers or images are introduced by the action of laser radiation. According to the present invention, the sequence of layers includes a marking layer (22) composed of an ink mixture (24, 26) exhibiting a laser-radiation-absorbing mixture component (26) and a laser-radiation-transparent mixture component (24), the identifiers being visually and/or mechanically perceptible due to an irreversible change in the optical properties of the ink mixture (24, 26), effected by the action of the laser radiation.

Claims

1. A value document, especially a banknote, having a sequence of layers into which visually and/or mechanically perceptible identifiers in the form of patterns, letters, numbers or images are introduced by the action of laser radiation, characterized in that the sequence of layers contains a marking layer composed of an ink mixture containing optically variable color pigments and exhibiting a laser-radiation-absorbing mixture component and a laser-radiation-transparent mixture component, the identifiers being visually and/or mechanically perceptible due to an irreversible change in the optical properties of the ink mixture, effected by the action of the laser radiation.

2. The value document according to claim 1, characterized in that the introduced identifiers are visually perceptible without auxiliary means.

3. The value document according to claim 2, characterized in that the ink mixture contains optically variable liquid crystal pigments as the laser-radiation-transparent mixture component.

4. The value document according to claim 2, characterized in that the ink mixture contains a transparent intaglio ink as the laser-radiation-transparent mixture component.

5. The value document according to claim 2, characterized in that the ink mixture contains optically variable interference layer pigments as the absorbing mixture component.

6. The value document according to claim 1, characterized in that the ink mixture contains as the absorbing mixture component an absorbing ink component whose optical properties are irreversibly changeable by the action of the laser radiation.

7. The value document according to claim 6, characterized in that the absorbing ink component contains an intaglio ink, a metallic ink or metallic pigments, a luminescent ink or luminescent pigments, glossy pigments or a thermochromic ink.

8. The value document according to claim 1, characterized in that the ink mixture contains an ink component that coacts with the absorbing mixture component, and whose optical properties are irreversibly changeable by the absorption of the laser radiation by the absorbing mixture component, especially the temperature rise caused thereby.

9. The value document according to claim 8, characterized in that the coacting ink component contains an intaglio ink, a metallic ink or metallic pigments, a luminescent ink or luminescent pigments, glossy pigments or a thermochromic ink.

10. The value document according to claim 8, characterized in that the absorbing mixture component contains soot, graphite, TiO₂ or an infrared absorber.

11. The value document according to claim 1, characterized in that the sequence of layers exhibits at least one laser-radiation-absorbing layer, which is disposed between the marking layer and the substrate of the value document.

12. The value document according to claim 1, characterized in that the sequence of layers exhibits at least one laser-radiation-absorbing layer and at least one laser-radiation-transparent layer, which are disposed between the marking layer and the substrate of the value document.

13. The value document according to claim 12, characterized in that a laser-radiation-transparent layer is disposed between the absorbing layer and the marking layer.

14. The value document according to claim 12, characterized in that a laser-radiation-transparent layer is disposed between the absorbing layer and the substrate of the value document.

15. The value document according to claim 11, characterized in that the absorbing layer is structured to bear information.

16. The value document according to claim 11, characterized in that a laser-radiation-transparent layer is structured to bear information.

17. The value document according to claim 15, characterized in that the information-bearing structurings are at least partially produced with printing technology.

18. The value document according to claim 15, characterized in that the information-bearing structurings are at least partially produced by the action of the laser radiation, especially by a selective ablation of an absorbing layer.

19. The value document according to claim 1, characterized in that the sequence of layers contains, in addition to the marking layer, an additional layer composed of an ink mixture exhibiting a laser-radiation-absorbing mixture component and a laser-radiation-transparent mixture component, the additional ink mixture layer being disposed between the marking layer and the substrate of the value document.

20. The value document according to claim 19, characterized in that the additional ink mixture layer exhibits an ink mixture containing optically variable color pigments and exhibiting a laser-radiation-absorbing mixture component and a laser-radiation-transparent mixture component.

21. The value document according to claim 19, characterized in that the additional ink mixture layer is structured to bear information.

22. The value document according to claim 15, characterized in that the information-bearing structurings form at least part of the identifiers and are visually perceptible due to the irreversible change in the optical properties of the ink mixture.

49. The value document according to claim 1, characterized in that the identifiers comprise an individualization mark, such as a sequential serial number, a symbol code, such as a bar or matrix code, or the like.

23. A value document, especially a banknote, having a sequence of layers into which identifiers in the form of patterns, letters, numbers or images are introduced by the action of laser radiation, characterized in that the sequence of layers contains a marking layer composed of an ink mixture exhibiting a laser-radiation-absorbing mixture component and a laser-radiation-transparent mixture component, the identifiers, due to an irreversible change in the optical properties of the ink mixture, effected by the action of the laser radiation, being mechanically perceptible but not being visually perceptible, or at least not without auxiliary means.

24. The value document according to claim 23, characterized in that the introduced identifiers are perceptible in the infrared spectral range.

25. The value document according to claim 23, characterized in that the introduced identifiers are perceptible following irradiation with ultraviolet radiation.

26. The value document according to claim 23, characterized in that the absorbing mixture component and the transparent mixture component appear in the same tone in the visible spectral range.

27. The value document according to claim 26, characterized in that the ink mixture visually exhibits a hue that differs from black.

28. The value document according to claim 23, characterized in that the proportion of the transparent mixture component outweighs the proportion of the absorbing mixture component in the ink mixture.

29. The value document according claim 28, characterized in that the transparent mixture component in the ink mixture exhibits a proportion of 60% or more.

30. The value document according to claim 28, characterized in that the transparent mixture component in the ink mixture exhibits a proportion of 70% or more, preferably of 80% or more.

31. A value document, especially a banknote, having a sequence of layers into which visually perceptible identifiers in the form of patterns, letters, numbers or images are introduced by the action of laser radiation, the sequence of layers exhibiting at least one laser-radiation-absorbing layer, characterized in that the sequence of layers exhibits at least one laser-radiation-transparent layer in addition to the absorbing layer, at least one of the absorbing or transparent layers containing optically variable color pigments and the identifiers being visually perceptible due to a selective ablation of the absorbing layer, effected by the action of the laser radiation.

32. The value document according to claim 31, characterized in that the absorbing layer is structured to bear information.

33. The value document according to claim 31, characterized in that the at least one laser-radiation-transparent layer is structured to bear information.

34. The value document according to claim 32, characterized in that the information-bearing structurings are at least partially produced with printing technology.

35. The value document according to claim 32, characterized in that the information-bearing structurings are at least partially produced by the action of the laser radiation, especially by a selective ablation of an absorbing layer.

36. The value document according to claim 31, characterized in that the optically variable color pigments are liquid crystal pigments or interference layer pigments.

37. A value document, especially a banknote, having a sequence of layers into which mechanically perceptible identifiers in the form of patterns, letters, numbers or images are introduced by the action of laser radiation, the sequence of layers exhibiting at least one laser-radiation-absorbing layer, characterized in that the sequence of layers exhibits at least one laser-radiation-transparent layer in addition to the absorbing layer, the absorbing layer and the transparent layer appearing in the same tone in the visible spectral range, and the identifiers, due to a selective change in the absorbing layer, effected by the action of the laser radiation, being mechanically perceptible but not being visually perceptible, or at least not without auxiliary means.

38. The value document according to claim 37, characterized in that the absorbing layer and the transparent layer visually exhibit a hue that differs from black.

39. The value document according to claim 37, characterized in that the transparent layer exhibits a greater thickness than the absorbing layer.

40. The value document according to claim 37, characterized in that the absorbing layer is disposed above the transparent layer.

43. The value document according to claim 37, characterized in that the absorbing layer is structured to bear information.

44. The value document according to claim 37, characterized in that a laser-radiation-transparent layer is structured to bear information.

45. The value document according to claim 43, characterized in that the information-bearing structurings are at least partially produced with printing technology.

46. The value document according to claim 37, characterized in that the information-bearing structurings are at least partially produced by the action of the laser radiation, especially by a selective ablation of an absorbing layer.

47. The value document according to claim 37, characterized in that the introduced identifiers are perceptible in the infrared spectral range.

48. The value document according to claim 37, characterized in that the introduced identifiers are perceptible following irradiation with ultraviolet radiation.

41. A value document, especially a banknote, having a sequence of layers into which mechanically perceptible identifiers in the form of patterns, letters, numbers or images are introduced by the action of laser radiation, the sequence of layers exhibiting at least one laser-radiation-absorbing layer, characterized in that the sequence of layers and the underlying value document substrate appear in the same tone in the visible spectral range, and the identifiers, due to a selective change in the absorbing layer, effected by the action of the laser radiation, being mechanically perceptible but not being visually perceptible, or at least not without auxiliary means.

42. The value document according to claim 41, characterized in that the absorbing layer and the underlying value document substrate visually exhibit a hue that differs from black.

50. A security element for value documents, especially banknotes, having a sequence of layers into which visually and/or mechanically perceptible identifiers in the form of patterns, letters, numbers or images are introduced by the action of laser radiation, characterized in that the sequence of layers contains a marking layer composed of an ink mixture containing optically variable color pigments and exhibiting a laser-radiation-absorbing mixture component and a laser-radiation-transparent mixture component, the identifiers being visually and/or mechanically perceptible due to an irreversible change in the optical properties of the ink mixture, effected by the action of the laser radiation.

51. The security element according to claim 50, characterized in that the introduced identifiers are visually perceptible without auxiliary means.

52. A security element for value documents, especially banknotes, having a sequence of layers into which identifiers in the form of patterns, letters, numbers or images are introduced by the action of laser radiation, characterized in that the sequence of layers contains a marking layer composed of an ink mixture exhibiting a laser-radiation-absorbing mixture component and a laser-radiation-transparent mixture component, the identifiers, due to an irreversible change in the optical properties of the ink mixture, effected by the action of the laser radiation, being mechanically perceptible, but are not visually perceptible, or at least not without auxiliary means.

53. The security element according to claim 52, characterized in that the sequence of layers is formed with introduced identifiers that are perceptible in the infrared spectral range, are perceptible following irradiation with ultraviolet radiation, and/or comprise an individualization mark, such as a sequential serial number, a symbol code, such as a bar or matrix code, or the like.

54. A security element for value documents, especially banknotes, having a sequence of layers into which visually perceptible identifiers in the form of patterns, letters, numbers or images are introduced by the action of laser radiation, the sequence of layers exhibiting at least one laser-radiation-absorbing layer, characterized in that the sequence of layers exhibits at least one laser-radiation-transparent layer in addition to the absorbing layer, at least one of the absorbing or transparent layers containing optically variable color pigments and the identifiers being visually perceptible due to a selective ablation of the at least one absorbing layer, effected by the action of the laser radiation.

55. The security element according to claim 54, characterized in that the sequence of layers is formed in that the absorbing layer is structured to bear information and/or the at least one laser-radiation-transparent layer is structured to bear information.

56. A security element for value documents, especially banknotes, having a sequence of layers into which mechanically perceptible identifiers in the form of patterns, letters, numbers or images are introduced by the action of laser radiation, the sequence of layers exhibiting at least one laser-radiation-absorbing layer, characterized in that the sequence of layers exhibits at least one laser-radiation-transparent layer in addition to the absorbing layer, the absorbing layer and the transparent layer appearing in the same tone in the visible spectral range, and the identifiers, due to a selective change in the absorbing layer, effected by the action of the laser radiation, being mechanically perceptible but not being visually perceptible, or at least not without auxiliary means.

57. The security element according to claim 56, characterized in that the sequence of layers is formed in that the absorbing layer and the transparent layer visually exhibit a hue that differs from black.

58. A method for manufacturing a security element or a value document having a sequence of layers, in which

a predefined laser wavelength is chosen,

to a substrate or to a layer of the sequence of layers is applied a marking layer composed of an ink mixture containing optically variable color pigments and exhibiting a mixture component that absorbs the laser radiation of the predefined laser wavelength and a mixture component that is transparent to the laser radiation of the predefined laser wavelength, and

through impingement on the sequence of layers by laser radiation of the predefined laser wavelength, identifiers are introduced into the sequence of layers in the form of patterns, letters, numbers or images that are visually and/or mechanically perceptible due to an irreversible change in the optical properties of the ink mixture, effected by the action of the laser radiation.

60. The method according to claim 58, characterized in that at least one laser-radiation-absorbing layer is applied, especially is imprinted, between the marking layer and the substrate of the value document or security element.

61. The method according to claim 58, characterized in that at least one laser-radiation-absorbing layer and one laser-radiation-transparent layer is applied, especially is imprinted, between the marking layer and the substrate of the value document or security element.

63. The method according to claim 60 at least one of claims 60 to 62, characterized in that the absorbing layer is structured to bear information.

64. The method according to claim 60 at least one of claims 60 to 63, characterized in that a laser-radiation-transparent layer is structured to bear information.

65. The method according to claim 63, characterized in that the information-bearing structurings are at least partially produced with printing technology.

66. The method according to claim 63, characterized in that the information-bearing structurings are at least partially produced by the action of the laser radiation, especially by a selective ablation of an absorbing layer.

69. The method according to claim 58, characterized in that an infrared laser in the wavelength range of 0.8 μ

m to 3 μ

m, especially a Nd;

YAG laser or a Nd;

YVO₄ laser, is used as the laser source.

70. The method according to claim 69, characterized in that vectors are inscribed in the sequence of layers with the infrared laser, the infrared laser being operated with a pulse frequency between 20 kHz and continuous wave, an output between 10 and 100 W and a transverse speed between 3 and 30 m/s.

71. The method according to claim 69, characterized in that a dot grid is inscribed in the sequence of layers with the infrared laser, the infrared laser being operated with a pulse frequency between 20 kHz and 80 kHz, an output between 0.5 and 4 W and for a dot density between 250 and 4800 dpi.

59. A method for manufacturing a security element or a value document having a sequence of layers, in which

a predefined laser wavelength is chosen,

to a substrate or to a layer of the sequence of layers is applied a marking layer composed of an ink mixture exhibiting a mixture component that absorbs the laser radiation of the predefined laser wavelength and a mixture component that is transparent to the laser radiation of the predefined laser wavelength, and

through impingement on the sequence of layers by laser radiation of the predefined laser wavelength, identifiers are introduced into the sequence of layers in the form of patterns, letters, numbers or images that, due to an irreversible change in the optical properties of the ink mixture, effected by the action of the laser radiation, are mechanically perceptible but are not visually perceptible, or at least not without auxiliary means.

62. A method for manufacturing a security element or of a value document having a sequence of layers, in which

a predefined laser wavelength is chosen,

to a substrate or to a layer of the sequence of layers are applied at least one layer that absorbs the laser radiation of the predefined laser wavelength and one layer that is transparent to the laser radiation of the predefined laser wavelength, at least one of the absorbing or transparent layers containing optically variable color pigments, and

through impingement on the sequence of layers by laser radiation of the predefined laser wavelength, identifiers are introduced into the sequence of layers in the form of patterns, letters, numbers or images that are visually perceptible due to a selective ablation of the absorbing layer, effected by the action of the laser radiation.

67. A method for manufacturing a security element or a value document having a sequence of layers, in which

a predefined laser wavelength is chosen,

to a substrate or to a layer of the sequence of layers are applied at least one layer that absorbs the laser radiation of the predefined laser wavelength and one layer that is transparent to the laser radiation of the predefined laser wavelength, the transparent and the absorbing layer appearing in the same tone in the visible spectral range, and

through impingement on the sequence of layers by laser radiation of the predefined laser wavelength, identifiers are introduced into the sequence of layers in the form of patterns, letters, numbers or images that, due to a selective change in the absorbing layer, effected by the action of the laser radiation, are mechanically perceptible but are not visually perceptible, or at least not without auxiliary means.

68. A method for manufacturing a value document having a sequence of layers, in which

a predefined laser wavelength is chosen,

to the value document substrate is applied a sequence of layers that appears in the same tone in the visible spectral range and having at least one layer that absorbs the laser radiation of the predefined laser wavelength, and

through impingement on the sequence of layers by laser radiation of the predefined laser wavelength, identifiers are introduced into the sequence of layers in the form of patterns, letters, numbers or images that, due to a selective change in the absorbing layer, effected by the action of the laser radiation, are mechanically perceptible but are not visually perceptible, or at least not without auxiliary means.