Printed document comprising a luminescent authenticity feature

• US 6,383,618 B1
• Filed: 01/24/2000
• Issued: 05/07/2002
• Est. Priority Date: 02/02/1998
• Status: Expired due to Term

• Current Assignee: Giesecke & Devrient (Giesecke & Devrient GmbH)
• Original Assignee: Giesecke & Devrient GmbH
• Inventors: Kaule, Wittich, Schwenk, Gerhard, Stenzel, Gerhard
• Primary Examiner(s): Jones, Deborah
• Assistant Examiner(s): BLACKWELL, GWENDOLYN
• Application Number:
  US09/381,643
• Time in Patent Office: 834 Days
• Field of Search: 428/67, 428/199, 428/203, 428/204, 428/207, 428/211, 428/333, 428/403, 428/464, 428/537.5, 428/696, 428/913, 428/916, 283/74, 283/57, 283/904, 283/901, 283/113, 283/114, 283/107, 427/7, 427/57, 252/301.4 R
• US Class Current: 428/195.1
• CPC Class Codes: B41M 3/144 using fluorescent, luminescent or iridescent effects
• CPC Class Codes: B42D 25/29 Securities; Bank notes
• CPC Class Codes: B42D 25/378 Special inks
• CPC Class Codes: C09K 11/7708 Vanadates; Chromates; Molybdates; Tungstates
• CPC Class Codes: C09K 11/7776 Vanadates; Chromates; Molybdates; Tungstates
• CPC Class Codes: Y10S 283/901 Concealed data
• CPC Class Codes: Y10S 428/916 Fraud or tamper detecting
• CPC Class Codes: Y10T 428/22 Nonparticulate element embedded or inlaid in substrate and visible
• CPC Class Codes: Y10T 428/24802 Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.]
• CPC Class Codes: Y10T 428/24835 including developable image or soluble portion in coating or impregnation [e.g., safety paper, etc.]
• CPC Class Codes: Y10T 428/24934 including paper layer

Abstract

The invention concerns a printed valuable document with at least one authentication mark in the form of a luminescent substance based on a host lattice doped with at least one rare earth metal. The host lattice largely absorbs light in the entire visible region of the spectrum, is excitable in substantial parts of the visible region of the spectrum, and is at least partially transparent at least in the wavelength range between 0.8 μm and 1.1 μm. The host lattice also features a garnet or perovskite structure. The rare earth metal emits light in the wavelength range between 0.8 μm and 1.1 μm.

Claims

1. Printed valuable document, with at least one authentication mark in the form of a luminescent substance based on a host lattice doped with at least one rare earth metal, which largely absorbs light in the entire visible region of the spectrum, is excitable in substantial parts of the visible region of the spectrum and is at least partially transparent at least in the wavelength range between 0.8 and 1.1 μ

m, whereby the at least one rare earth metal emits in the wavelength range between 0.8 μ

m and 1.1 μ

m, and that the host lattice has a garnet or perovskite structure.

2. Printed valuable document according to claim 1, wherein the rare earth metal is ytterbium, praseodymium, or neodymium.

3. Printed valuable document according to claim 1, wherein the host lattice contains chromium as an absorptive component.

4. Printed valuable document according to claim 1, wherein the garnet structure can be described by the general formula

5. Printed valuable document according to claim 4, wherein the index x fulfils the condition 0.3<

x<

2.5.

6. Printed valuable document according to claim 4, wherein the luminescent substance can be described by the formula

7. Printed valuable document according to claim 1, wherein the perovskite structure can be described by the general formula

8. Printed valuable document according to claim 7, wherein the luminescent substance can be described according to the formula

9. Printed valuable document according to claim 1, wherein the luminescent substance is mixed into a printing ink, which additionally contains visible color additives.

10. Printed valuable document according to claim 1, wherein the luminescent substance is mixed into the paper pulp.

11. Printed valuable document according to claim 1, wherein the luminescent substance is provided on or in a substrate material, which is at least partially embedded in the paper pulp.

12. Printed valuable document according to claim 11, wherein the substrate material consists of plastic.

13. Printed valuable document according to claim 11, wherein the substrate material is a security thread or mottling fiber.

14. Printed valuable document according to claim 1, wherein the luminescent substance is provided as an invisible and at least partial coating on the valuable document.

15. Printed valuable document according to claim 14, wherein the coating is a stripe.

16. Security element, which features at least one substrate material and one luminescent substance based on a host lattice doped with at least one rare earth metal, which largely absorbs light in the visible spectral region, is excitable in substantial parts of the visible spectral region, and is at least partially transparent at least in the wavelength range between 0.8 μ

m and 1.1 μ

m, whereby the at least one rare earth metal emits light in the wavelength range between 0.8 μ

m and 1.1 I μ

m, and the host lattice has a garnet or perovskite structure.

17. Security element according to claim 16, wherein the luminescent substance is provided in the volume of the substrate material.

18. Security element according to claim 17, wherein the luminescent substance is present in the substrate material in a concentration between 0.01 and 10% by weight.

19. Security element according to claim 16, wherein the luminescent substance is present in a layer applied to the substrate material.

20. Security element according to claim 19, wherein the luminescent substance is present in a printing ink in a concentration between 0.5 and 40% by weight.

21. Security element according to claim 16, wherein the substrate material consists of plastic.

22. Security element according to claim 16, wherein the substrate material consists of paper.

23. Security element according to claim 16, wherein the substrate material is a security thread, mottling fiber, planchet, or label.

24. Security element according to claim 17, wherein the luminescent substance is present in the substrate material in a concentration between 0.1 and 5% by weight.

25. Security element according to claim 19, wherein the luminescent substance is present in a printing ink in a concentration between 20 and 30% by weight.