Optically-based methods and apparatus for performing sorting coding and authentication using a gain medium that provides a narrowband emission
First Claim
1. A method for processing a document, comprising the steps of:
- providing a document to be authenticated, the document comprising a substrate and at least one security structure comprised of an optical gain medium and a structure for at least one of (a) favoring the creation of at least one mode or (b) supporting amplified spontaneous emission;
illuminating at least a portion of the document with light selected for exciting the gain medium;
detecting an 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 and confirmed to be a laser-like emission.
1 Assignment
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Accused Products
Abstract
Disclosed are methods and apparatus for at least one of authenticating, sorting or counting documents, as well as to security structures contained within documents and to documents containing security structures. A security device or structure includes an optical gain medium and a structure having boundaries that impart an overall geometry to the structure that, in combination with at least one material property of the structure, favors in one embodiment the creation of at least one mode that enhances an emission of electromagnetic radiation within a narrow band of wavelengths. Suitable shapes for the structure comprise elongated, generally cylindrical shapes such as filaments, a sphere shape, a partial-sphere shape, a toroidal shape, a cubical and other polyhedral shape, and a disk shape. The structure preferably comprises at least one of a monolithic structure or a multi-layered structure or an ordered structure that may provide for distributed optical feedback. In a preferred embodiment the security device forms a part of a currency, a passport, a lottery ticket, a negotiable security, a credit card or debit card, or any substrate or carrier which it is desired to at least one of authenticate, count, encode, sort or verify.
98 Citations
23 Claims
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1. A method for processing a document, comprising the steps of:
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providing a document to be authenticated, the document comprising a substrate and at least one security structure comprised of an optical gain medium and a structure for at least one of (a) favoring the creation of at least one mode or (b) supporting amplified spontaneous emission;
illuminating at least a portion of the document with light selected for exciting the gain medium;
detecting an 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 and confirmed to be a laser-like emission. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. Apparatus for at least one of authenticating, sorting or counting documents, comprising:
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a light source for illuminating all or a portion of a document, the document comprising a substrate and at least one device located in or on said substrate, said device being comprised of an optical gain medium and a structure for at least one of (a) favoring the creation of at least one mode or (b) supporting amplified spontaneous emission for outputting at least one predetermined emission wavelength, said light source outputting light having wavelengths that are predetermined to excite said gain medium;
at least one detector responsive to said predetermined emission wavelength for detecting the presence of the at least one predetermined emission wavelength; and
decision logic, having an input coupled to an output of said at least one detector, for at least one indicating the authenticity of the document based at least in part on a detection of the at least one predetermined emission wavelength, for counting the document based at least in part on a detection of the at least one predetermined emission wavelength or on the absence the at least one predetermined emission wavelength, or for sorting the document based at least in part on a detection of the at least one predetermined emission wavelength or on the absence the at least one predetermined emission wavelength. - View Dependent Claims (12, 13, 14, 15, 16)
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17. A method for processing a document, comprising the steps of:
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providing a document comprising a substrate and at least one device that is comprised of an optical gain medium and a structure coupled to said gain medium for at least one of (a) favoring the creation of at least one mode or (b) supporting amplified spontaneous emission, said device encoding information that is made manifest by an emission from said device;
illuminating at least a portion of the document with light selected for exciting the gain medium;
detecting an emission of at least one wavelength from the document in response to the step of illuminating; and
obtaining the information that was encoded in the device from the detected emission. - View Dependent Claims (18, 19, 20, 21, 22, 23)
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Specification