Counterfeit-resistant materials and a method and apparatus for authenticating materials

• US 6,246,061 B1
• Filed: 09/01/1999
• Issued: 06/12/2001
• Est. Priority Date: 10/22/1993
• Status: Expired due to Term

• Current Assignee: UT-Battelle LLC
• Original Assignee: UT-Battelle LLC
• Inventors: Klatt, Leon N., Ramsey, J. Michael
• Primary Examiner(s): Hannaher, Constantine
• Assistant Examiner(s): GAGLIARDI, ALBERT J
• Application Number:
  US09/516,606
• Time in Patent Office: 650 Days
• Field of Search: 250/458.1, 250/459.1, 359/352, 235/454, 235/491
• US Class Current: 250/458.1
• CPC Class Codes: B42D 25/29 Securities; Bank notes
• CPC Class Codes: D21H 15/00 Pulp or paper, comprising fibres or web-forming material characterised by features other than their chemical constitution
• CPC Class Codes: D21H 21/48 Elements suited for physical verification, e.g. by irradiation
• CPC Class Codes: G06K 19/086 with markings consisting of randomly placed or oriented elements, the randomness of the elements being useable for generating a unique identifying signature of the record carrier, e.g. randomly placed magnetic fibers or magnetic particles in the body of a credit card
• CPC Class Codes: G07D 7/1205 Testing spectral properties

Abstract

Fluorescent dichroic fibers randomly incorporated within a media provide an improved method for authentication and counterfeiting protection. The dichroism is provided by an alignment of fluorescent molecules along the length of the fibers. The fluorescent fibers provide an authentication mechanism of varying levels of capability. The authentication signature depends on four parameters, the x,y position, the dichroism and the local environment. The availability of so many non-deterministic variables makes production of counterfeit articles (e.g., currency, credit cards, etc.) essentially impossible Counterfeit-resistant articles, an apparatus for authenticating articles, and a process for forming counterfeit-resistant media are also provided&

Claims

1. A method for authenticating media, comprising:

a) providing a stored representation of an image corresponding to a media having a plurality of randomly disposed optically detectable indicators therein;

b) comparing the stored representation with a subsequently acquired representation of an image corresponding to a media having a plurality of randomly disposed optically detectable indicators therein; and

c) authenticating the media based on the comparison of the respective pluralities of randomly disposed indicators, said comparison being sensitive to an optical polarization of the optically detectable indicators.

2. The method according to claim 1, wherein the indicators have a fluorescent characteristic such that when illuminated with light of a first wavelength, a polarized light of a second wavelength is emitted, said first and second wavelengths being different;

and wherein said imaging step comprises ascertaining the fluorescent characteristic.

3. The method according claim 2, wherein a fluorescent emission of the indicators is polarized;

and wherein said imaging preserves information relating to a polarization of fluorescent emissions.

4. The method according to claim 1, wherein the indicators each comprise a polymer having a crystalline characteristic and fluorescent dye molecules, the fluorescent dye molecules being organized within the polymer resulting in a detectable dichroic optical property.

5. The method according to claim 1, wherein the indicators comprise fibers formed of fluorescent dye molecules and an organized linear chain polymer structure, the fluorescent dye molecules being aligned within the polymer resulting in a dichroic optical property.

6. The method according to claim 1, further comprising the steps of

a) illuminating the medium with light having a wavelength corresponding to a specific fluorescent absorption of the indicators;

b) selectively measuring a dichroic axis of light corresponding to the fibers having a wavelength corresponding to a specific fluorescent emission of the indicators;

c) said comparing comprising correlating a dichroic axis of emission of the stored representation with the subsequently acquired representation.