Process for authenticity determination of security documents with security features in the form of luminescing substances

• US 4,533,244 A
• Filed: 03/07/1984
• Issued: 08/06/1985
• Est. Priority Date: 05/30/1980
• Status: Expired due to Term

• Current Assignee: GAO Gesellschaft Fur Automation und Organisation mbH
• Original Assignee: GAO Gesellschaft Fur Automation und Organisation mbH
• Inventors: Kaule, Wittich, Schwenk, Gerhard, Stenzel, Gerhard
• Primary Examiner(s): McGraw, Vincent P.
• Assistant Examiner(s): Turner, S. A.
• Application Number:
  US06/586,962
• Time in Patent Office: 517 Days
• Field of Search: 356/71, 356/318, 356/319, 250/271, 250/361.1, 250/363, 250/365, 250/458, 250/461
• US Class Current: 356/71
• CPC Class Codes: B41M 3/144 using fluorescent, luminescent or iridescent effects
• CPC Class Codes: D21H 21/48 Elements suited for physical verification, e.g. by irradiation
• CPC Class Codes: G06K 19/14 the marking being sensed by radiation
• CPC Class Codes: G07D 7/12 Visible light, infrared or ultraviolet radiation
• CPC Class Codes: Y10S 101/46 Printing operation controlled by code indicia on printing plate or substate
• CPC Class Codes: Y10S 428/908 Impression retention layer, e.g. print matrix, sound record
• CPC Class Codes: Y10S 428/916 Fraud or tamper detecting
• CPC Class Codes: Y10S 428/917 Electroluminescent
• CPC Class Codes: Y10S 428/918 Material abnormally transparent
• CPC Class Codes: Y10T 428/24901 including coloring matter
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 428/261 In terms of molecular thickness or light wave length
• CPC Class Codes: Y10T 428/2991 Coated
• CPC Class Codes: Y10T 428/31634 Next to cellulosic

Abstract

Security paper with narrow band luminescing authenticity characteristics which can only be excited in substantially the same wavelength region in which it also emits. With these authenticity characteristics therefore the authenticity signal is overlapped or covered by the test signal of several orders of magnitude stronger. The authenticity of the security papers cannot accordingly be tested with the normal processes or devices for determining of luminescence. The test devices used take advantage of the decay behavior of the luminescence emission for detection. The authenticity characteristics can be added to the paper material, the printing ink used, further mottling fibres or security threads.

Claims

1. A process for authenticity determination of a security document, comprising:

providing said document with a luminescing substance having a known excitation spectrum and a known emission spectrum wherein at least a portion of said excitation spectrum and a portion of said emission spectrum are contained in a narrow band of wavelengths and at least a portion of said excitation spectrum overlaps at least a portion of said emission spectrum in said narrow wavelength band;

exciting said document within said narrow band; and

sensing the emissions of said security documents in said narrow band caused by said excitation in said narrow band.

2. A process according to claim 1, wherein said exciting step comprises introducing excitation radiation into an optically more highly refractive layer of said security document, which layer contains said luminescing substance, whereby said excitation radiation is totally reflected within said layer and only luminescence radiation emerging from said layer is observed.

3. A process according to claim 1, comprising sensing the decay behavior of said emissions.

4. A process according to claim 3, comprising subjecting said security document to excitation radiation with said document in a first zone, and said step of sensing comprises sensing said decay behavior with said document in a second zone.

5. A device for testing a security document having an authenticity feature in the form of a luminescing substance comprising:

a housing;

a light source arranged in said housing;

at least one photo-detector; and

a transport means for transporting a security document from said light source to said at least one photo-detector, within the decay time of the luminescing material of said security document.

6. A device according to claim 5, wherein said light source provides sufficient radiation to approximately cover the luminescing substance of said security document.

7. A device according to claim 5, wherein the transport means moves the security document continuously with a constantly defined speed.

8. A device according to claim 5, wherein the transport means comprises an electromagnetically operated claw which grasps the securty document and transports it from said light source to said at least one photo-detector.

9. A device according to claim 8, wherein the light source and the transport means are controlled by a positioning switch operated by a front edge of the security paper.

10. A device according to claim 7, wherein several photo-detectors are arranged sequentially in the transport direction.

11. A device according to claim 6, wherein said luminescing substance is divided into several coding fields, and including a plurality of photo-detectors, said photo-detectors and light source being arranged correspondingly to test said several coding fields.

12. A device according to claim 7, including means for operating said light source synchronously with the transport speed and the photo-detectors.