Luminescent phosphor compounds, articles including such compounds, and methods for their production and use
First Claim
1. Luminescent phosphor compositions for security applications, wherein the luminescent phosphor compositions are obtained from different lots of phosphor raw materials, wherein phosphor raw materials from which the respective luminescent phosphor compositions are synthesized have varying impurity amounts and wherein each luminescent phosphor composition comprises:
- one or more emitting ions, one or more disturbing ions, optionally one or more sensitizing ions, and a quantity of rare earth impurities other than the one or more emitting ions and the one or more sensitizing ions;
wherein the one or more emitting ions have one or more first decay time constants when the one or more emitting ions are undisturbed, the one or more disturbing ions are different from the one or more emitting ions, and the one or more disturbing ions are included in the luminescent phosphor compositions in a quantity that will cause at least one of the one or more emitting ions to have a pre-defined, target disturbed decay time constant that is greater than zero and less than a corresponding one of the one or more first decay time constants;
wherein the first decay time constant and the target disturbed decay time constants can be distinguished by an authentication device,wherein the luminescent phosphor compositions have substantially equal target disturbed decay time constants for the corresponding one or more first decay time constants despite the presence of a varying amount of impurity ions therein from the respective phosphor raw materials.
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Accused Products
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).
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Citations
17 Claims
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1. Luminescent phosphor compositions for security applications, wherein the luminescent phosphor compositions are obtained from different lots of phosphor raw materials, wherein phosphor raw materials from which the respective luminescent phosphor compositions are synthesized have varying impurity amounts and wherein each luminescent phosphor composition comprises:
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one or more emitting ions, one or more disturbing ions, optionally one or more sensitizing ions, and a quantity of rare earth impurities other than the one or more emitting ions and the one or more sensitizing ions; wherein the one or more emitting ions have one or more first decay time constants when the one or more emitting ions are undisturbed, the one or more disturbing ions are different from the one or more emitting ions, and the one or more disturbing ions are included in the luminescent phosphor compositions in a quantity that will cause at least one of the one or more emitting ions to have a pre-defined, target disturbed decay time constant that is greater than zero and less than a corresponding one of the one or more first decay time constants; wherein the first decay time constant and the target disturbed decay time constants can be distinguished by an authentication device, wherein the luminescent phosphor compositions have substantially equal target disturbed decay time constants for the corresponding one or more first decay time constants despite the presence of a varying amount of impurity ions therein from the respective phosphor raw materials. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for producing luminescent phosphor compositions from different lots of phosphor raw materials, wherein the method comprises the steps of:
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obtaining a phosphor raw material that includes a phosphor host crystal lattice material, one or more emitting ions, optionally one or more sensitizing ions, and a quantity of rare earth impurities other than the one or more emitting ions and the one or more sensitizing ions, wherein the phosphor raw material is characterized by one or more first decay time constants; synthesizing a disturbed phosphor composition that includes the phosphor host crystal lattice material, the one or more emitting ions, the quantity of rare earth impurities, and a quantity of one or more disturbing ions; measuring one or more second decay time constants of the disturbed phosphor composition; determining whether the one or more second decay time constants are substantially equal to one or more target disturbed decay time constants that are greater than zero and less than corresponding ones of the one or more first decay time constants; when at least one of the one or more second decay time constants is not substantially equal to the one or more target disturbed decay time constants, repeating the synthesizing, measuring, and determining steps for an additional candidate disturbed phosphor composition that has an adjusted quantity of the one or more disturbing ions that is different from the initial quantity; and synthesizing another disturbed phosphor composition from a different lot of phosphor raw materials than the disturbed phosphor composition, wherein the different lot of phosphor raw materials has a varying impurity level from the impurity level of phosphor raw materials used to synthesize the disturbed phosphor composition, wherein the disturbed phosphor composition and the other disturbed phosphor composition have substantially equal target disturbed decay time constants for the corresponding one or more first decay time constants despite the presence of a varying amount of impurity ions therein from the respective phosphor raw materials. - View Dependent Claims (10, 11, 12)
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13. Articles comprising:
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a substrate; and an authentication feature on a surface of the substrate or integrated within the substrate, wherein authentication features of different articles comprise different luminescent phosphor compositions obtained from different lots of phosphor raw materials, wherein the phosphor raw materials from which the luminescent phosphor compositions are synthesized have varying impurity levels, and wherein each luminescent phosphor composition comprises; one or more emitting ions, one or more disturbing ions, optionally one or more sensitizing ions, and a quantity of rare earth impurities other than the one or more emitting ions and the one or more sensitizing ions; wherein the one or more emitting ions have one or more first decay time constants when the one or more emitting ions are undisturbed, the one or more disturbing ions are different from the one or more emitting ions, and the one or more disturbing ions are included in the phosphor compositions in a quantity that will cause at least one of the one or more emitting ions to have a pre-defined, target disturbed decay time constant that is greater than zero and less than a corresponding one of the one or more first decay time constants; wherein the first decay time constant and the target disturbed decay time constants can be distinguished by an authentication device, and wherein the luminescent phosphor compositions all have substantially equal target disturbed decay time constants for the corresponding one or more first decay time constants despite the presence of a varying amount of impurity ions therein from the respective phosphor raw materials. - View Dependent Claims (14, 15, 16, 17)
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Specification