Security document with optically excitable dyes for authenticity check

• US 6,234,537 B1
• Filed: 08/13/1999
• Issued: 05/22/2001
• Est. Priority Date: 08/14/1998
• Status: Expired due to Fees

• Current Assignee: Bundesdruckerei GmbH (Government of Germany)
• Original Assignee: Bundesdruckerei GmbH (Government of Germany)
• Inventors: Ahlers, Benedikt, Franz-Burgholz, Arnim, Kappe, Frank, Gutmann, Roland, Paugstadt, Ralf
• Primary Examiner(s): Fridie, Jr., Willmon
• Application Number:
  US09/374,882
• Time in Patent Office: 648 Days
• Field of Search: 283/86, 283/87, 283/88, 283/89, 283/90, 283/91, 283/92, 283/93, 283/95, 283/114
• US Class Current: 283/86
• CPC Class Codes: B41M 3/14 Security printing securities B42D25/29
• CPC Class Codes: B41M 5/287 using microcapsules or microspheres only
• CPC Class Codes: B42D 2035/34 Markings visible under particular conditions or containing coded information
• CPC Class Codes: B42D 25/23 Identity cards
• CPC Class Codes: B42D 25/29 Securities; Bank notes

Abstract

A security document with optically excitable dyes for authenticity checking. Dyes are applied to or embedded in the security documents. The dyes are advantageously embedded in a carrier material which in conjunction with the dyes forms a laser-active element. Certain optically excitable dyes are incorporated in a security document in such a way that when the security and/or sensitive document is optically excited, the dyes embedded in the security and/or sensitive document resonate with the material of the securities and secure documents, so that a well-defined narrow spectrum of all excited materials is emitted.

Claims

1. A security document comprising at least one optically excitable dye having a first emission characteristic for authenticity checking;

a carrier material;

the at least one optically excitable dye is embedded in the carrier material and, in conjunction with the carrier material, forms a laser-active element; and

wherein the at least one dye is embedded in a resonator comprising a coating of reflecting layers disposed on both sides of the carrier material containing the at least one dye.

3. The security document according to claim 1, wherein the resonator includes geometry and material characteristics, whereby the security document can be identified.

4. The security document according to claim 3, wherein the at least one dye is directly incorporated in a layer of the security document and the reflecting layers form part of the security document.

5. The security document according claim 4, further comprising pigment platelets including a carrier layer doped with laser dye and two mutually parallel reflecting layers disposed on both sides of the carrier layer and wherein the dyes are bedded in the pigment platelets.

6. The security document according to claim 4, wherein the at least one dye is embedded in pigment spheres including a carrier material doped with the laser dye and a reflecting layer surrounding the carrier material.

7. The security document according to claim 6, wherein the carrier material is a material that is transparent for both an exciting wavelength and an emitted wavelength.

8. The security document according to claim 7, further comprising pigment particles, and wherein the at least one dye, pigment platelets, pigment particles are micro-encapsulated in a materials.

9. The security document according to claim 8, wherein the at least one dye, pigment platelets and pigment particles are incorporated in color components of a printing ink.

10. The security document according to claim 9, wherein the document comprised paper and wherein the at least one dye, pigment platelets and pigment particles are incorporated in the paper.

11. The security document according to claim 9, wherein the document comprises paper having a plastic substrate and wherein the at least one dye, pigment platelets and pigment particles are incorporated in the plastic substrate.

12. The security document according to 9, wherein the document comprised paper including paper additives and wherein the at least one dye, pigment platelets and pigment particles are incorporated in the paper additives.

2. A security document comprising

two optically excitable dyes having each a different emission characteristic for authenticity checking;

a carrier material;

said two optically excitable dyes are each embedded in the carrier material and, in conjunction with the carrier material, form a laser-active element; and

wherein the two optically excitable dyes are embedded in a resonator comprising a coating of reflecting layers disposed on both sides of the carrier material containing each of the two dyes.