Nanoparticles as covert taggants in currency, bank notes, and related documents
OwnerMichael Natan, Scott Norton +3inventors
InventorsMichael Natan, Scott Norton, Richard Freeman, Sharron Penn, Ian Walton
Life of this patent
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Abstract
Methods for applying security tags and/or data to currency and other documents and systems for use are provided.
Claims23
A method for providing a security feature for documents, the method comprising:
- a) providing a document to be protected;
- b) applying at least one tag to at least a first portion of the document, wherein said tag comprises a metal nanoparticle, a Raman-active molecule associated with the surface of the metal nanoparticle, and an encapsulant surrounding said metal nanoparticle and said Raman-active molecule, wherein the metal is Raman enhancing, and wherein said particle has a measurable SERS spectrum.
A method for detecting a counterfeit document, comprising:
- a) scanning a document having security data encoded thereon in machine-readable form, wherein said security data comprises at least one SERS spectrum, said SERS spectrum being read from a tag, said tag comprising a metal nanoparticle, a Raman-active molecule associated with the surface of the metal nanoparticle, and an encapsulant surrounding said metal nanoparticle and said Raman-active molecule, wherein the metal is Raman enhancing;
- and
- b) comparing said scanned security data with pre-stored security data corresponding to said document, whereby a counterfeit document is detected.
An apparatus for detecting a counterfeit document, comprising
- means for scanning a document having security data encoded thereon in machine-readable form, wherein said security data comprises a SERS spectrum, said SERS spectrum being read from a tag, said tag comprising a metal nanoparticle, wherein the metal is Raman enhancing, a Raman-active molecule associated with the surface of the metal nanoparticle, and an encapsulant surrounding said metal nanoparticle and said Raman-active molecule.
A system for identifying a tag, wherein the tag comprises a Raman enhancing metal nanoparticle having a measurable SERS spectrum, a Raman-active molecule associated with the surface of the metal nanoparticle, and an encapsulant surrounding the metal nanoparticle and the Raman-active molecule, the system comprising:
- a processor;
- a detector coupled to the processor and operable to detect a SERS spectrum of a tag to be identified;
- and
- a reference database coupled to the processor and comprising a list of possible components of the tag to be identified and a reference spectrum associated with each possible component;
- the processor being configured to execute instructions for:
- receiving the detected spectrum from the detector;
- accessing the reference database;
- and
- generating a weighted linear combination of the spectra of the possible components which substantially corresponds to the detected spectrum whereby the components of the weighted linear combination substantially identify the tag to be identified.
A computer program product of a computer readable medium usable with a programmable computer, the computer program product having computer-readable code embodied therein for identifying a tag, wherein the tag comprises a Raman enhancing metal nanoparticle having a measurable SERS spectrum, a Raman-active molecule associated with the surface of the metal nanoparticle, and an encapsulant surrounding the metal nanoparticle and the Raman-active molecule, the computer-readable code comprising instructions for:
- receiving a detected spectrum from a SERS detector
- accessing a reference database comprising a list of possible components of a tag to be identified and a reference spectrum associated with each possible component;
- and
- generating a weighted linear combination of the spectra of the possible components which substantially corresponds to the detected spectrum whereby the components of the weighted linear combination substantially identify the tag to be identified.
Dependencies are inferred from the claim text.