Optically active materials and articles and systems in which they may be used
First Claim
1. A method of manufacturing a retroreflective article, comprising:
- obtaining a retroreflective sheeting; and
positioning an infrared-reflecting multi-layer optical film on the retroreflective sheeting to form a pattern;
wherein the infrared-reflecting multi-layer optical film is transparent and not significantly visible in the visible light spectrum; and
wherein the retroreflective sheeting causes incident light to retroreflect via a retroreflective light path, and wherein the infrared-reflecting multi-layer optical film causes incident infrared light to be reflected from the retroreflective light path.
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Accused Products
Abstract
The inventors of the present application developed novel optically active materials, methods, and articles. One embodiment of the present application is an optically active article, comprising: an infrared-reflecting material positioned adjacent to an optically active substrate such that the infrared-reflecting material forms a pattern that can be read by an infrared sensor when the optically active substrate is illuminated by an infrared light source. Another embodiment of the present application relates to a method of manufacturing an optically active article, comprising: obtaining an optically active sheeting; and positioning an infrared-reflecting material on the optically active sheeting to form a pattern. The optically active article may be, for example, a license plate.
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Citations
14 Claims
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1. A method of manufacturing a retroreflective article, comprising:
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obtaining a retroreflective sheeting; and positioning an infrared-reflecting multi-layer optical film on the retroreflective sheeting to form a pattern; wherein the infrared-reflecting multi-layer optical film is transparent and not significantly visible in the visible light spectrum; and wherein the retroreflective sheeting causes incident light to retroreflect via a retroreflective light path, and wherein the infrared-reflecting multi-layer optical film causes incident infrared light to be reflected from the retroreflective light path. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A retroreflective article comprising:
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retroreflective sheeting; and an infrared-reflecting multi-layer optical film disposed on at least a portion of the retroreflective sheeting, wherein infrared-reflecting multi-layer optical film is not significantly visible in the visible light spectrum; and wherein the retroreflective sheeting retroreflects incident light via a retroreflective light path, and wherein the infrared-reflecting multi-layer optical film causes incident infrared light to be reflected from the retroreflective light path. - View Dependent Claims (8, 9, 10)
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11. A retroreflective sign comprising:
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retroreflective sheeting including covert indicia, wherein the covert indicia in the form of a pattern is infrared-reflecting multi-layer optical film and not significantly visible in the visible light spectrum; wherein the retroreflective sheeting retroreflects incident light via a retroreflective light path, and wherein the infrared-reflecting multi-layer optical film causes infrared light to be reflected from the retroreflective light path. - View Dependent Claims (12, 13, 14)
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Specification