Optically variable security devices
3 Assignments
0 Petitions
Accused Products
Abstract
A security article includes a light transmissive substrate having a first surface and an opposing second surface, with the first surface having an optical interference pattern such as a holographic image pattern or an optical diffraction pattern thereon. A color shifting optical coating is formed on the substrate such as on the interference pattern or on the opposing second surface of the substrate, with the optical coating providing an observable color shift as the angle of incident light or viewing angle changes. Various processes can be utilized to form the security article, such as vacuum coating processes, lamination, laser scribing, and laser imaging. The security article can be affixed to a variety of objects through various attachment mechanisms, such as pressure sensitive adhesives or hot stamping processes, to provide for enhanced security measures such as anticounterfeiting.
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Citations
56 Claims
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1-36. -36. (canceled)
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37. A security article is provided comprising:
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a substrate;
a diffractive grating having a grating pattern directly on the surface of the substrate or upon a coating adjacent to the substrate;
an optically variable coating directly on the diffractive grating so that a layer of the optically variable coating adjacent to the diffractive grating conforms to the grating pattern and whereby the grating pattern is replicated into the optically variable coating, wherein the optically variable coating includes an absorber layer, a dielectric layer and a reflector layer for providing an observable color shift as the angle of incident light or viewing angle changes wherein the colorshift is a combination of thin film and diffractive interference effects. - View Dependent Claims (38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56)
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Specification