Retroreflective articles and retroreflective elements comprising a spherical core and two concentric optical interference layers
First Claim
1. A retroreflective element comprising:
- a solid spherical core wherein the solid spherical core is transparent and comprises an outer core surface, the outer core surface providing a first interface;
a first complete concentric optical interference layer having a thickness of up to approximately 600 nm, wherein the first complete concentric optical interference layer is transparent and has (i) an inner surface directly overlying the outer core surface and (ii) an outer surface, the outer surface of the first complete concentric optical interference layer providing a second interface;
a second complete concentric optical interference layer having a thickness of up to approximately 600 nm, wherein the second complete concentric optical interference layer is transparent and has (i) an inner surface directly overlying the outer surface of the first complete concentric optical interference layer and (ii) an outer surface, the outer surface of the second complete concentric optical interference layer providing a third interface.
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Accused Products
Abstract
Retroreflective elements and articles that include such elements. The retroreflective elements (100) include a solid spherical core (110) having an outer surface. A first complete concentric optical interference layer (112) overlays the outer surface of the core providing a first interface between the core and the first optical interference layer, and a second complete concentric optical interference layer (122) overlays the first optical interference layer to provide a second interface between the first optical interference layer and the second optical interference layer. In some embodiments, a third complete concentric optical interference layer overlays the second optical interference layer to provide a third interface between the second optical interference layer and the third optical interference layer. The retroreflective articles include a substrate having a first major surface and a second major surface with a plurality of the retroreflective elements affixed along the first major surface of the substrate.
61 Citations
38 Claims
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1. A retroreflective element comprising:
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a solid spherical core wherein the solid spherical core is transparent and comprises an outer core surface, the outer core surface providing a first interface; a first complete concentric optical interference layer having a thickness of up to approximately 600 nm, wherein the first complete concentric optical interference layer is transparent and has (i) an inner surface directly overlying the outer core surface and (ii) an outer surface, the outer surface of the first complete concentric optical interference layer providing a second interface; a second complete concentric optical interference layer having a thickness of up to approximately 600 nm, wherein the second complete concentric optical interference layer is transparent and has (i) an inner surface directly overlying the outer surface of the first complete concentric optical interference layer and (ii) an outer surface, the outer surface of the second complete concentric optical interference layer providing a third interface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38)
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Specification