US5903340A
Expired / Lapsed
US
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Optically-based methods and apparatus for performing document authentication
Assignee: Brown University Research Foundation Inc
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Filing: 1997-04-10
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Granted: 1999-05-11
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Expires: 2017-04-10
Abstract
Abstract This invention teaches a method for authenticating a document. The method includes the steps of: (a) providing a document to be authenticated; (b) illuminating at least a portion of the document with laser light that exceeds a threshold fluence; (c) detecting a narrow band laser-like emission of at least one wavelength from the document in response to the step of illuminating; and (d) declaring the document to be authentic only if the laser-like emission is detected.
Inventors
- 👤 Nabil M Lawandy
- 👤 Timothy J Driscoll
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 16:20
CPC Classifications
G; G06; G06V; G06V10/00; G06V10/88; G07; G07D; G07D7/00; G07D7/06; G07D7/12; G07D7/1205; G07D7/005
Claims Analysis
Total Claims: 47
Claim 1
Independent Claim
69 words
A method for authenticating a document, comprising the steps of: providing a document to be authenticated; illuminating at least a portion of the document with laser light that exceeds a threshold fluence; detecting a narrow band substantially non-saturable amplified spontaneous emission of at least one wavelength from the document in response to the step of illuminating; and declaring the document to be authentic only if the emission is detected.
Claim 2
Independent Claim
69 words
A method for authenticating a document, comprising the steps of: providing a document to be authenticated; illuminating at least a portion of the document with laser light that exceeds a threshold fluence; detecting a narrow band substantially non-saturable amplified spontaneous emission of at least one wavelength from the document in response to the step of illuminating; and declaring the document to be authentic only if the emission is detected.
Claim 3
Dependent Claim
46 words
A method as in claim 1, wherein step of providing a document provides a document having embedded threads, individual ones of which comprise a substrate material and an optical gain medium in combination with scatterers for providing the emission in response to the step of illuminating.
Claim 4
Dependent Claim
42 words
A method as in claim 1, wherein step of providing a document provides a document having an ink bearing surface, the ink including an optical gain medium in combination with scatterers for providing the emission in response to the step of illuminating.
Claim 5
Dependent Claim
44 words
A method as in claim 1, wherein step of providing a document provides a document having a fluorescent whitening agent (FWA), the FWA functioning as an optical gain medium in combination with scatterers for providing the emission in response to the step of illuminating.
Claim 6
Dependent Claim
53 words
A method as in claim 1, wherein step of providing a document provides a document having embedded threads, individual ones of said threads being coated with a polymer-based coating, the polymer-based coating functioning as an optical gain medium in combination with scatterers for providing the emission in response to the step of illuminating.
Claim 7
Dependent Claim
64 words
A method as in claim 1, wherein step of providing a document provides a document having embedded threads, each of the threads being comprised of N filaments individual ones of which comprise a substrate material and an optical gain medium in combination with scatterers for providing the emission in response to the step of illuminating, wherein each thread emits light at N distinguishable wavelengths.
Claim 8
Dependent Claim
44 words
A method as in claim 1, wherein step of providing a document provides a document having embedded threads, each of the threads being comprised of a multilayered structure having a least one layer comprised of the optical gain material, and an underlying metalization layer.
Claim 9
Dependent Claim
32 words
A method as in claim 7, wherein the at least one layer of optical gain material is differentiated into a plurality of regions, each of the regions emitting with a characteristic wavelength.
Claim 10
Dependent Claim
13 words
A method as in claim 7, wherein the underlying metalization layer is patterned.
Claim 11
Dependent Claim
27 words
A method as in claim 7, wherein the underlying metalization layer is patterned and modulates a thickness of an overlying layer comprised of the optical gain material.
Claim 12
Dependent Claim
31 words
A method as set forth in claim 1, wherein the step of detecting detects a presence of a secondary emission peak that results from a photoconversion of a primary emission peak.
Claim 13
Dependent Claim
59 words
A document, comprising: a matrix formed as a planar substrate; and at least one security structure embedded in said matrix, said at lest one security structure comprising an optical gain medium that is responsive to illumination with laser light that exceeds a threshold fluence for emitting a narrow band substantially non-saturable amplified spontaneous emission of at least one wavelength.
Claim 14
Dependent Claim
59 words
A document, comprising: a matrix formed as a planar substrate; and at least one security structure embedded in said matrix, said at lest one security structure comprising an optical gain medium that is responsive to illumination with laser light that exceeds a threshold fluence for emitting a narrow band substantially non-saturable amplified spontaneous emission of at least one wavelength.
Claim 15
Dependent Claim
29 words
A document as in claim 12, wherein said security structure is comprised of a metalized substrate having a coating comprised of said gain medium on at least one surface.
Claim 16
Dependent Claim
22 words
A document as in claim 12, wherein said security structure is comprised of one or more filaments that include said gain medium.
Claim 17
Dependent Claim
20 words
A document as in claim 12, wherein said security structure is comprised of a planchette that includes said gain medium.
Claim 18
Dependent Claim
61 words
A document as in claim 12, wherein said security structure is comprised of a metalized substrate having a coating comprised of said optical gain medium on at least one surface, said metalized substrate being disposed such that a distance from said at least one surface to an illuminated surface of said planar substrate varies along a length of said metalized substrate.
Claim 19
Dependent Claim
114 words
Apparatus for authenticating a document, comprising: a laser for illuminating all or a portion of a document, said laser outputting light having wavelengths that are predetermined to generate a narrow band substantially non-saturable amplified spontaneous emission, having at least one predetermined emission wavelength, from the document or a structure contained within the document; at least one photodetector responsive to said predetermined emission wavelength for detecting the presence of the at least one predetermined emission wavelength; and decision means, having an input coupled to an output of said at least one photodetector, for indicating the authenticity of the document based at least in part on a detection of the at least one predetermined emission wavelength.
Claim 20
Dependent Claim
114 words
Apparatus for authenticating a document, comprising: a laser for illuminating all or a portion of a document, said laser outputting light having wavelengths that are predetermined to generate a narrow band substantially non-saturable amplified spontaneous emission, having at least one predetermined emission wavelength, from the document or a structure contained within the document; at least one photodetector responsive to said predetermined emission wavelength for detecting the presence of the at least one predetermined emission wavelength; and decision means, having an input coupled to an output of said at least one photodetector, for indicating the authenticity of the document based at least in part on a detection of the at least one predetermined emission wavelength.
Claim 21
Dependent Claim
33 words
Apparatus as in claim 17, wherein said structure is comprised of an embedded security thread comprised of a substrate material and an optical gain medium in combination with scatterers for providing the emission.
Claim 22
Dependent Claim
28 words
Apparatus as in claim 17, wherein the document has an ink bearing surface, the ink including an optical gain medium in combination with scatterers for providing the emission.
Claim 23
Dependent Claim
30 words
Apparatus as in claim 17, wherein the document has a fluorescent whitening agent (FWA), the FWA functioning as an optical gain medium in combination with scatterers for providing the emission.
Claim 24
Dependent Claim
37 words
Apparatus as in claim 17, wherein said structure is comprised of an embedded security thread coated with a polymer-based coating, the polymer-based coating functioning as an optical gain medium in combination with scatterers for providing the emission.
Claim 25
Dependent Claim
49 words
Apparatus as in claim 17, wherein said structure is comprised of an embedded security thread comprised of N filaments individual ones of which comprise a substrate material and an optical gain medium in combination with scatterers for providing the emission, wherein each thread emits light at N distinguishable wavelengths.
Claim 26
Dependent Claim
32 words
Apparatus as in claim 17, wherein said structure is comprised of an embedded multilayered security thread having at least one layer comprised of an optical gain medium, and an underlying metalization layer.
Claim 27
Dependent Claim
31 words
Apparatus as in claim 23, wherein the at least one layer of optical gain material is differentiated into a plurality of regions, each of the regions emitting with a characteristic wavelength.
Claim 28
Dependent Claim
12 words
Apparatus as in claim 23, wherein the underlying metalization layer is patterned.
Claim 29
Dependent Claim
26 words
Apparatus as in claim 23, wherein the underlying metalization layer is patterned and modulates a thickness of an overlying layer comprised of the optical gain medium.
Claim 30
Dependent Claim
28 words
Apparatus as in claim 17, wherein said structure is comprised of a metalized substrate having a coating comprised of an optical gain medium on at least one surface.
Claim 31
Dependent Claim
27 words
Apparatus as in claim 17, wherein said structure is comprised of one or more filaments that include an optical gain medium integrally formed therewith or coated thereon.
Claim 32
Dependent Claim
19 words
Apparatus as in claim 17, wherein said structure is comprised of a planchette that includes an optical gain medium.
Claim 33
Dependent Claim
58 words
Apparatus as in claim 17, wherein said structure is comprised of a metalized substrate having a coating comprised of an optical gain medium on at least one surface, said metalized substrate being disposed such that a distance from said at least one surface to an illuminated surface of said document varies along a length of said metalized substrate.
Claim 34
Dependent Claim
141 words
Apparatus for distinguishing a first type of currency having a first monetary value from other types of currency having different monetary values, comprising: a laser for illuminating all or a portion of a currency of interest, said laser outputting light having wavelengths that are predetermined to generate a narrow band substantially non-saturable amplified spontaneous emission, having at least one predetermined emission wavelength, from the first type of currency or a structure contained within the first type of currency; at least one photodetector responsive to said predetermined emission wavelength for detecting the presence of the at least one predetermined emission wavelength; and decision means, having an input coupled to an output of said at least one photodetector, for distinguishing the currency has being one of the first type or another type based at least in part on the output of said photodetector.
Claim 35
Dependent Claim
141 words
Apparatus for distinguishing a first type of currency having a first monetary value from other types of currency having different monetary values, comprising: a laser for illuminating all or a portion of a currency of interest, said laser outputting light having wavelengths that are predetermined to generate a narrow band substantially non-saturable amplified spontaneous emission, having at least one predetermined emission wavelength, from the first type of currency or a structure contained within the first type of currency; at least one photodetector responsive to said predetermined emission wavelength for detecting the presence of the at least one predetermined emission wavelength; and decision means, having an input coupled to an output of said at least one photodetector, for distinguishing the currency has being one of the first type or another type based at least in part on the output of said photodetector.
Claim 36
Dependent Claim
48 words
A fiber, said fiber being responsive to incident light having wavelengths selected to generate a narrow band substantially non-saturable amplified spontaneous emission from said fiber, said emission comprising at least one narrow band of emission wavelengths defined at least in part by scattering at boundaries of said fiber.
Claim 37
Dependent Claim
48 words
A fiber, said fiber being responsive to incident light having wavelengths selected to generate a narrow band substantially non-saturable amplified spontaneous emission from said fiber, said emission comprising at least one narrow band of emission wavelengths defined at least in part by scattering at boundaries of said fiber.
Claim 38
Dependent Claim
15 words
A fiber as in claim 32, wherein said fiber comprises a portion of a document.
Claim 39
Dependent Claim
16 words
A fiber as in claim 32, wherein said fiber comprises a portion of a negotiable instrument.
Claim 40
Dependent Claim
15 words
A fiber as in claim 32, wherein said fiber comprises a portion of a currency.
Claim 41
Dependent Claim
22 words
A fiber as in claim 32, wherein said fiber comprises a portion of an object that represents a unit of monetary value.
Claim 42
Dependent Claim
47 words
An object that is responsive to incident light having wavelengths selected to generate a narrow band substantially non-saturable amplified spontaneous emission from said object, said emission comprising at least one narrow band of emission wavelengths defined at least in part by scattering at boundaries of said object.
Claim 43
Dependent Claim
47 words
An object that is responsive to incident light having wavelengths selected to generate a narrow band substantially non-saturable amplified spontaneous emission from said object, said emission comprising at least one narrow band of emission wavelengths defined at least in part by scattering at boundaries of said object.
Claim 44
Dependent Claim
15 words
An object as in claim 37, wherein said object comprises a portion of a document.
Claim 45
Dependent Claim
16 words
An object as in claim 37, wherein said object comprises a portion of a negotiable instrument.
Claim 46
Dependent Claim
15 words
An object as in claim 37, wherein said object comprises a portion of a currency.
Claim 47
Dependent Claim
22 words
An object as in claim 37, wherein said object comprises a portion of an object that represents a unit of monetary value.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2002-05-10 | 2002-11-09 | 2003-05-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2006-05-10 | 2006-11-09 | 2007-05-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2010-05-10 | 2010-11-09 | 2011-05-11 | $7700.00 | Window Closed / Lapsed |