Printed document having a value, with luminescent authenticity feature

• US 6,506,476 B1
• Filed: 11/30/1999
• Issued: 01/14/2003
• Est. Priority Date: 02/02/1998
• Status: Expired due to Term

• Current Assignee: Giesecke & Devrient (Giesecke & Devrient GmbH)
• Original Assignee: Glesecke & Devrlent GmbH
• Inventors: Kaule, Wittich, Schwenk, Gerhard, Stenzel, Gerhard
• Primary Examiner(s): Jones, Deborah
• Assistant Examiner(s): BLACKWELL, GWENDOLYN
• Application Number:
  US09/381,640
• Time in Patent Office: 1,141 Days
• Field of Search: 428/67, 428/80, 428/199, 428/204, 428/207, 428/211, 428/333, 428/403, 428/464, 428/537.7, 428/690, 428/913, 428/916, 283/57, 283/74, 283/113, 283/114, 283/107, 283/901, 283/904, 427/7
• 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: C09K 11/7774 Aluminates
• CPC Class Codes: C09K 11/7776 Vanadates; Chromates; Molybdates; Tungstates
• CPC Class Codes: G06K 19/06046 Constructional details
• CPC Class Codes: Y10S 283/901 Concealed data
• CPC Class Codes: Y10S 283/904 Credit card
• 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.]

Abstract

The invention concerns a printed valuable document with at least one authentication feature 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 in the visible region of the spectrum, is excitable at least in parts of the visible region of the spectrum and transparent at least in partial areas of the IR spectral region. The luminescent substance is present in the volume of the valuable document in such a concentration that the characteristics of the valuable document just remain unimpaired. The rare earth metal concerned is thulium.

Claims

1. Printed valuable document with at least one authentication feature in the form of a luminescent substance based on a host lattice doped with at least one rare earth metal, which largely absorbs and is excitable in the visible region of the spectrum and is transparent at least in parts of the IR spectral region, whereby the rare earth metal is thulium, and the luminescent substance is present in the volume of the valuable document in a concentration of no more than 5 percent by weight.

2. Printed valuable document according to claim 1, wherein the valuable document consists of paper and that the luminescent substance is present in the paper in a concentration of 0.05 to 1 percent by weight.

7. Printed valuable document according to claim 1, wherein the optically transparent region of the host lattice doped with rare earth metal lies in the range between 1 μ

m and 10 μ

m.

8. Printed valuable document according to claim 1, wherein the host lattice contains iron or chromium as absorptive elements.

9. Printed valuable document according to claim 1, wherein the host lattice has a garnet or perovskite structure.

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

11. Printed valuable document according to claim 10, wherein the index x fulfils the condition 0<

×

<

2.

12. Printed valuable document according to claim 10, wherein the luminescent substance can be described with the general formula

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

14. Printed valuable document according to claim 13, wherein the luminescent substance can be described with the general formula

15. Printed valuable document according to claim 1, wherein the luminescent substance has a quantum yield of 50 to 90%.

23. Printed valuable document according to claim 12, wherein the luminescent substance can be described with the general formula

24. Printed valuable document according to claim 14, wherein the luminescent substance can be described with the general formula

3. Printed valuable document with at least one authentication feature in the form of a luminescent substance based on a host lattice doped with at least one rare earth metal, which largely absorbs and is excitable in the visible region of the spectrum and is transparent at least in parts of the IR spectral region, whereby the rare earth metal is thulium, and the luminescent substance is present in a layer applied to the valuable document in a concentration between 1 and 40 percent by weight.

4. Printed valuable document according to claim 3, wherein the luminescent substance is provided as an invisible, at least partial, coating on the valuable document.

5. Printed valuable document according to claim 3, wherein the luminescent substance is mixed into a printing ink, which additionally contains visible colour additions.

6. Printed valuable document according to claim 3, wherein the coating takes the form of one or more stripes.

22. Printed valuable document according to claim 3, wherein the layer applied to the valuable document is a printing ink in which the luminescent substance is present in a concentration between 10 and 30 percent by weight.

16. Security element having at least one substrate material and a luminescent substance based on a host lattice doped with at least one rare earth metal, which largely absorbs and is excitable in the visible region of the spectrum and is transparent at least in parts of the IR spectral region, whereby the rare earth metal is thulium, and the luminescent substance is present in the volume of the substrate material in a concentration of no more than 6 percent by weight and said substrate material consists of paper.

17. Security element according to claim 16, wherein the substrate material consists of plastic and the luminescent substance is present in the plastic in a concentration of no more than 2 percent by weight.

19. Security element according to claim 16, wherein the security element takes the form of a stripe or band.

20. Security element according to claim 19, wherein the substrate material takes the form of security threads or mottling fibres.

21. Security element according to claim 16, wherein the security element takes the form of a label.

25. Security element according to claim 16, wherein the substrate material consists of paper and the luminescent substance is present in the paper in a concentration in the range from 0.05 to 1 percent by weight.

18. Security element having at least one substrate material and a luminescent substance based on a host lattice doped with at least one rare earth metal, which largely absorbs and is excitable in the visible region of the spectrum and is transparent at least in parts of the IR spectral region, whereby the rare earth metal is thulium, and the luminescent substance is present in a layer applied to the substrate material in a concentration in the range between 1 and 40 percent by weight;

with the proviso that said luminescent substance is present in a printing ink.

26. Security element according to claim 18, wherein the luminescent substance is present in a printing ink in a concentration in the range between 10 and 30 percent by weight.