Retrochromic articles
First Claim
1. An article having a retrochromic pattern, the pattern comprising first and second viewable retroreflective regions having substantially different retroreflective colors if viewed using the same illumination source, wherein at least one of the viewable retroreflective regions comprises at least 10 intrinsically retrochromic beads and is retrochromic, and wherein the intrinsically retrochromic beads are selected from the group consisting of:
- i) intrinsically retrochromic beads having a spherical core, wherein the spherical core has a uniform and complete concentric optical interference layer thereon, and wherein the spherical core has a refractive index of at least 1.8, andii) intrinsically retrochromic beads having microcrystalline regions therein, wherein the microcystalline regions have a size of from 50 to 250 nanometers, andiii) combinations thereof.
2 Assignments
0 Petitions
Accused Products
Abstract
Retrochromic articles have a retrochromic pattern comprising first and second viewable retroreflective regions, wherein at least one viewable retroreflective region comprises a plurality of intrinsically retrochromic beads. Methods for making such articles are also provided. Articles according to the present invention have covert security features, and may be used, for example, to authenticate security articles.
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Citations
103 Claims
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1. An article having a retrochromic pattern, the pattern comprising first and second viewable retroreflective regions having substantially different retroreflective colors if viewed using the same illumination source, wherein at least one of the viewable retroreflective regions comprises at least 10 intrinsically retrochromic beads and is retrochromic, and wherein the intrinsically retrochromic beads are selected from the group consisting of:
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i) intrinsically retrochromic beads having a spherical core, wherein the spherical core has a uniform and complete concentric optical interference layer thereon, and wherein the spherical core has a refractive index of at least 1.8, and ii) intrinsically retrochromic beads having microcrystalline regions therein, wherein the microcystalline regions have a size of from 50 to 250 nanometers, and iii) combinations thereof. - 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, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69)
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70. A method of making an article having a retrochromic pattern comprising:
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providing a substrate; affixing a first retroreflective material to the substrate to form a first viewable retroreflective region; and affixing a second retroreflective material to the substrate to form a second viewable retroreflective region; wherein the first and second retroreflective materials form a retrochromic pattern, the pattern comprising first and second viewable retroreflective regions having substantially different retroreflective colors if viewed using the same illumination source, wherein at least one of the viewable retrorefleclive regions comprises at least 10 intrinsically retrochromic beads and is retrochromic, and wherein the intrinsically retrochromic beads are selected from the group consisting of; i) intrinsically retrochromic beads having a spherical core, wherein the spherical core has a uniform and complete concentric optical interference layer thereon, and wherein the spherical core has a refractive index of at least 1.8, and ii) intrinsically retrochromic beads having microcrystalline regions therein, wherein the microcystalline regions have a size of from 50 to 250 nanometers, and iii) combinations thereof. - View Dependent Claims (71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99)
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100. An article having a retrochromic pattern, the pattern comprising first and second viewable retroreflective regions having substantially different retroreflective colors if viewed using the same illumination source, wherein at least one of the viewable retroreflective regions comprises intrinsically retrochromic beads which are non-randomly positioned with respect to adjacent beads, and wherein the intrinsically retrochromic beads are selected from the group consisting of:
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i) intrinsically retrochromic beads having a spherical core, wherein the spherical core has a uniform and complete concentric optical interference layer thereon, and wherein the spherical core has a refractive index of at least 1.8, and ii) intrinsically retrochromic beads having microcrystalline regions therein, wherein the microcrystalline regions have a size of from 50 to 250 nanometers, and iii) combinations thereof. - View Dependent Claims (101, 102, 103)
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Specification