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US 10,328,737 B2Granted
High refractive index coatings and their use in the protection of surface relief structures
AssigneeCCL Secure Pty Ltd
InventorsPhei Lok, Gary Fairless Power, Odisea Batistatos
Life of this patent
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Abstract
High refractive index coatings having metal oxide particles are disclosed. Dispersions of metal oxide particles in solvent are also disclosed. These find use in the protection of surface relief structures. In some disclosed embodiments, the coatings or dispersions contain UV-curable resins. The coatings and dispersions find application in the field of security devices and documents and tokens incorporating security devices.
Claims11
A security device comprising:
- a substrate;
- and
- a single-layer transparent protective coating, wherein:
- (i) the substrate has a surface relief structure, wherein:
- said surface relief structure is filled by the single-layer transparent protective coating to give a physically flat surface and wherein said physically flat surface is absent any surface relief, and
- wherein said single-layer transparent protective coating has a refractive index greater than a refractive index of the surface relief structure, or
- (ii) the single-layer transparent protective coating forms all or part of a surface relief structure, wherein:
- said surface relief structure of said single-layer transparent protective coating is filled by a layer of varnish to give a physically flat surface and wherein said physically flat surface is absent any surface relief, and
- wherein said single-layer transparent protective coating has a refractive index greater than a refractive index of the layer of varnish,
- wherein said single-layer transparent protective coating comprises a layer comprising particles of at least one metal oxide dispersed in a transparent varnish, wherein the particles have a primary crystallite size from 1 to 100 nm, and wherein said single-layer transparent protective coating is free of a high refractive index polymer, and
- wherein the concentration of particles is sufficiently high in the single-layer transparent protective coating to increase the refractive index of the single-layer transparent protective coating such that, in the case of (i), the single-layer transparent protective coating maintains an optical effect of the substrate surface relief structure or, in the case of (ii), the layer of varnish maintains an optical effect of the single-layer transparent protective coating surface relief structure.
8 more elements
A security device comprising:
- a substrate;
- and
- a single-layer transparent protective coating, wherein:
- the substrate has a surface relief structure, wherein:
- said surface relief structure is filled by the single-layer transparent protective coating to give a physically flat surface and wherein said physically flat surface is absent any surface relief, and
- wherein said single-layer transparent protective coating has a refractive index greater than a refractive index of the surface relief structure,
- wherein said single-layer transparent protective coating comprises a layer comprising particles of at least one metal oxide dispersed in a transparent varnish, wherein the particles have a primary crystallite size from 1 to 100 nm, and wherein said single-layer transparent protective coating is free of a high refractive index polymer, and
- wherein the concentration of particles is sufficiently high in the single-layer transparent protective coating to increase the refractive index of the single-layer transparent protective coating such that the single-layer transparent protective coating maintains an optical effect of the substrate surface relief structure.
5 more elements
A security device comprising:
- a substrate;
- and
- a single-layer transparent protective coating, wherein:
- the single-layer transparent protective coating forms all or part of a surface relief structure, wherein:
- said surface relief structure of said single-layer transparent protective coating is filled by a layer of varnish to give a physically flat surface and wherein said physically flat surface is absent any surface relief, and
- wherein said single-layer transparent protective coating has a refractive index greater than a refractive index of the layer of varnish,
- wherein said single-layer transparent protective coating comprises a layer comprising particles of at least one metal oxide dispersed in a transparent varnish, wherein the particles have a primary crystallite size from 1 to 100 nm, and wherein said single-layer transparent protective coating is free of a high refractive index polymer, and
- wherein the concentration of particles is sufficiently high in the single-layer transparent protective coating to increase the refractive index of the single-layer transparent protective coating such that the layer of varnish maintains an optical effect of the single-layer transparent protective coating surface relief structure.
5 more elements
Dependencies are inferred from the claim text.