Abstract: Luminescent taggant compositions, luminescent materials that include luminescent taggants, and articles including luminescent taggants are provided herein. In an embodiment, a luminescent taggant composition includes a first luminescent taggant, a second luminescent taggant, and a third luminescent taggant. The first luminescent taggant includes a first emitting ion that produces a first emission in a first taggant emission band when exposed to excitation energy. The second luminescent taggant includes a second emitting ion that is different from the first emitting ion and that produces a second emission in a second taggant emission band that is different from the first taggant emission band when exposed to excitation energy. The first luminescent taggant is substantially free of the second emitting ion and the second luminescent taggant is substantially free of the first emitting ion. The third luminescent taggant includes the first emitting ion and the second emitting ion.

Abstract: Coins or other value articles contain magnetic particles for changing the electromagnetic signature of the article and frustrate a counterfeiter's attempt to fake the article.

Abstract: Luminescent phosphor systems, methods of preparing luminescent phosphor systems, and articles that include the luminescent phosphor systems are provided herein. In an embodiment, a luminescent phosphor system includes a plurality of separate luminescent phosphor lots. The plurality of luminescent phosphor lots includes a first lot of a first luminescent phosphor compound and a second lot of a second luminescent phosphor compound. The first luminescent phosphor compound of the first lot includes zinc sulfide, copper ions, halogen ions and, optionally, at least one additional metal ion chosen from aluminum, manganese, and/or iron. The second luminescent phosphor compound of the second lot includes zinc sulfide, copper ions, halogen ions, and at least one additional metal ion chosen from aluminum and/or manganese. The first luminescent phosphor compound and the second luminescent phosphor compound have different decay time constants that are distinguishable by an authentication device.

Abstract: Embodiments include articles, authentication methods and apparatus, and article manufacturing methods. An article includes a substrate with a first luminescent taggant, and an extrinsic feature with a second luminescent taggant, which is positioned proximate a portion of the article surface. The first and second taggants produce emissions in overlapping emission bands as a result of exposure to excitation energy. Above the extrinsic feature, the substrate and extrinsic feature emissions combine in the overlapping emission band to produce “confounded” emissions that are distinguishable from the substrate emissions taken alone. An authentication system determines whether, in a region corresponding to a “substrate-only” region of an authentic article, emissions having first emission characteristics are detected in the overlapping emission band.

Abstract: Luminescent taggant compositions, luminescent materials that include luminescent taggants, and articles including luminescent taggants are provided herein. In an embodiment, a luminescent taggant composition includes a first luminescent taggant, a second luminescent taggant, and a third luminescent taggant. The first luminescent taggant includes a first emitting ion that produces a first emission in a first taggant emission band when exposed to excitation energy. The second luminescent taggant includes a second emitting ion that is different from the first emitting ion and that produces a second emission in a second taggant emission band that is different from the first taggant emission band when exposed to excitation energy. The first luminescent taggant is substantially free of the second emitting ion and the second luminescent taggant is substantially free of the first emitting ion. The third luminescent taggant includes the first emitting ion and the second emitting ion.

Abstract: Embodiments include luminescent phosphor compounds that include one or more emitting ions and one or more disturbing ions, and methods for their production. An emitting ion in the compound may be characterized by a first decay time constant when the emitting ion is undisturbed. However, a corresponding disturbing ion in the compound, which is different from the emitting ion, causes the emitting ion to have a pre-defined, target disturbed decay time constant that is greater than zero and less than the first decay time constant. An embodiment of an authentication system is configured to measure the decay time constant of a phosphor compound applied to an article, and to determine whether the decay time constant corresponds to a phosphor compound that includes a particular disturbing ion (e.g., in order to determine whether or not the article is authentic).

Abstract: Embodiments include articles, authentication methods and apparatus, and article manufacturing methods. An article includes a substrate with a first luminescent taggant, and an extrinsic feature with a second luminescent taggant, which is positioned proximate a portion of the article surface. The first and second taggants produce emissions in overlapping emission bands as a result of exposure to excitation energy. Above the extrinsic feature, the substrate and extrinsic feature emissions combine in the overlapping emission band to produce “confounded” emissions that are distinguishable from the substrate emissions taken alone. An authentication system determines whether, in a region corresponding to a “substrate-only” region of an authentic article, emissions having first emission characteristics are detected in the overlapping emission band.

Abstract: Cold-worked metal articles, methods of forming cold-worked metal articles, and methods of authenticating cold-worked metal articles are provided. In an embodiment, a cold-worked metal article includes a cold-worked metal-containing surface that defines pores. The cold-worked metal-containing surface includes luminescent phosphor particles disposed within the pores. The luminescent phosphor particles include a host crystal lattice material and at least one active ion that includes an absorbing ion and an emitting ion that is different from the absorbing ion. The luminescent phosphor particles are harder than the cold-worked metal-containing surface.

Abstract: Methods and apparatus for article authentication include an exciting radiation generator that exposes an area of the article to exciting radiation, and at least two radiation detectors that detect emitted radiation from the area in a first band and in a second band that does not overlap the first band. The first band corresponds with a first emission sub-band of an emitting ion, and the second band corresponds with a second emission sub-band of the same emitting ion. A processing system calculates a comparison value that represents a mathematical relationship (e.g., a ratio) between a first intensity of the emitted radiation in the first band with a second intensity of the emitted radiation in the second band, and determines whether the comparison value compares favorably with an authentication parameter. When the comparison value compares favorably with the authentication parameter, the article is identified as being authentic.

Abstract: Embodiments include luminescent phosphor compounds that include one or more emitting ions and one or more disturbing ions, and methods for their production. An emitting ion in the compound may be characterized by a first decay time constant when the emitting ion is undisturbed. However, a corresponding disturbing ion in the compound, which is different from the emitting ion, causes the emitting ion to have a pre-defined, target disturbed decay time constant that is greater than zero and less than the first decay time constant. An embodiment of an authentication system is configured to measure the decay time constant of a phosphor compound applied to an article, and to determine whether the decay time constant corresponds to a phosphor compound that includes a particular disturbing ion (e.g., in order to determine whether or not the article is authentic).

Abstract: Embodiments include luminescent materials and associated production methods. The material includes a crystal borate having a first substitutable element, neodymium substituted for the first substitutable element at a first substitution percentage of at least about 20 percent, and ytterbium substituted for the first substitutable element at a second substitution percentage. The material also may include chromium substituted for a second substitutable element. The material also may include a medium within which particles of the borate are incorporated. The medium, with the luminescent material particles, may form a security feature of an article. Embodiments of methods for identifying whether such a luminescent material is incorporated with an article include exposing a portion of the article to excitation in a chromium absorption band, and determining whether a detected emission produced by the article as a result of the excitation indicates an ytterbium emission after termination of the exposing step.

Abstract: Luminescent borates, luminescent materials, and articles incorporating such borates are provided herein. An embodiment of a luminescent borate includes a host borate that has a B9O16-comprising crystal lattice. Neodymium and/or ytterbium are present within the host borate, and one or more substitutable elements are optionally present along with the neodymium and/or ytterbium within the host borate. The one or more substitutable elements are different from neodymium and ytterbium.

Abstract: Cold-worked metal articles, methods of forming cold-worked metal articles, and methods of authenticating cold-worked metal articles are provided. In an embodiment, a cold-worked metal article includes a cold-worked metal-containing surface that defines pores. The cold-worked metal-containing surface includes luminescent phosphor particles disposed within the pores. The luminescent phosphor particles include a host crystal lattice material and at least one active ion that includes an absorbing ion and an emitting ion that is different from the absorbing ion. The luminescent phosphor particles are harder than the cold-worked metal-containing surface.

Abstract: Embodiments include luminescent materials and associated production methods. The material includes a crystal borate having a first substitutable element and a second substitutable element, one or more rare earth ions substituted for the first substitutable element, and chromium substituted for the second substitutable element. The one or more rare earth ions are selected from a group consisting of neodymium and ytterbium. The material also may include a medium within which particles of the borate are incorporated. The medium, with the luminescent material particles, may form a security feature of an article. Embodiments of methods for identifying whether such a luminescent material is incorporated with an article include exposing a portion of the article to excitation in a chromium absorption band, and determining whether a detected emission produced by the article as a result of the excitation indicates an ytterbium emission after termination of the exposing step.

Abstract: Embodiments include methods and apparatus for identifying a thermographic phosphor (e.g., Er:YIG) incorporated on or within an article. The method and apparatus embodiments include an excitation energy generator selectively exposing the article to excitation energy in an absorption band of the thermographic phosphor. An emitted radiation detector detects first emission characteristics of first emitted radiation from the article within an emission band of the thermographic phosphor when the article has a first temperature, and detects second emission characteristics of second emitted radiation from the article within the emission band when the article has a second temperature that is different from the first temperature. A temperature adjustment element is configured to adjust the temperature of the article. Embodiments further include a processing system determining whether the first emission characteristics are sufficiently different from the second emission characteristics.

Abstract: A value document authentication system comprising a value document substrate having a luminescent compound disposed on or in at least a portion of the value document substrate, wherein the luminescent compound (i) comprises a host lattice having at least one metallic ion with magnetic properties and is doped with at least one rare earth ion capable of emitting infrared radiation with at least one distinct infrared wavelength when excited with an exciting light source having sufficient energy to excite emission from the luminescent compound and (ii) has a pre-determined ratio of metallic ions to rare earth ions such that the ratio corresponds to a parameter of a pre-selected decision criteria, both of which properties are measured at the same location on the value document and used to authenticate the value document.

Abstract: Articles, methods of validating the articles, and validating systems are provided herein. In an embodiment, an article includes a substrate and a security feature on the substrate. The security feature includes a first region that has a first ink composition and a second region that has a second ink composition. The first ink composition includes a first luminescent phosphor and the second ink composition includes a second luminescent phosphor that is different from the first luminescent phosphor. The first luminescent phosphor and the second luminescent phosphor have indistinguishable excitation energy wavelengths, indistinguishable emission wavelengths, and distinguishable temporal decay properties.

Abstract: Luminescent borates, luminescent materials, and articles incorporating such borates are provided herein. An embodiment of a luminescent borate includes a host borate that has a B9O16-comprising crystal lattice. Neodymium and/or ytterbium are present within the host borate, and one or more substitutable elements are optionally present along with the neodymium and/or ytterbium within the host borate. The one or more substitutable elements are different from neodymium and ytterbium.

Abstract: Value documents or other articles having authentication features, authentication apparatuses, and methods of authentication are provided that relate to the use of taggants that absorb radiation from an illumination source and emit radiation in a manner that has a maximum intensity occurring a duration of time after the illumination source has been switched off. The taggants include a crystalline composition comprising a host crystal lattice doped with a first rare earth active ion, and in some examples a second rare earth active ion.

Abstract: Articles, methods of validating the articles, and validating systems are provided herein. In an embodiment, an article includes a substrate and a security feature on the substrate. The security feature includes a first region that has a first ink composition and a second region that has a second ink composition. The first ink composition includes a first luminescent phosphor and the second ink composition includes a second luminescent phosphor that is different from the first luminescent phosphor. The first luminescent phosphor and the second luminescent phosphor have indistinguishable excitation energy wavelengths, indistinguishable emission wavelengths, and distinguishable temporal decay properties.