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US5189553A
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Optimized construction of retroreflective articles for curved applications
Assignee: 3M Co
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Filing: 1992-06-08
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Granted: 1993-02-23
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Expires: 2012-06-08
Abstract
Abstract Retroreflective cube corner elements are arranged within layered articles at positions proximate a neutral axis to optimize their performance upon bending or twisting of the article. The elements and surfacs may be embodied in flexible sheeting materials suitable for curving about an object.
Inventors
- 👤 Kenneth L. Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 15:14
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/12; G02B5/122; G02B5/124
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
104 words
A retroreflective cube corner element laminated sheet for bending applications, comprising: a) a sheet outer surface designed for tension during laminated sheet bending and a sheet inner surface designed for compression during laminated sheet bending; b) a neutral bending axis region located relative to the outer surface and the inner surface so that the neutral bending axis region comprises a neutral bending axis which is substantially free of stress and deformation during laminated sheet bending; and c) a plurality of reflective cube corner elements having surfaces purposefully located proximate the neutral bending axis to provide enhanced retroreflective performance for a given radius of curvature.
Claim 2
Dependent Claim
104 words
A retroreflective cube corner element laminated sheet for bending applications, comprising: a) a sheet outer surface designed for tension during laminated sheet bending and a sheet inner surface designed for compression during laminated sheet bending; b) a neutral bending axis region located relative to the outer surface and the inner surface so that the neutral bending axis region comprises a neutral bending axis which is substantially free of stress and deformation during laminated sheet bending; and c) a plurality of reflective cube corner elements having surfaces purposefully located proximate the neutral bending axis to provide enhanced retroreflective performance for a given radius of curvature.
Claim 3
Dependent Claim
45 words
The retroreflective sheet of claim 1 in which: a) each reflective cube comprises a cube base and a cube peak; and b) the base of each reflective cube is located within a range of 0 to 0.0254 millimeter (1 mil) from the neutral bending axis.
Claim 4
Dependent Claim
44 words
The retroreflective sheet of claim 1 in which: a) each reflective cube comprises a cube base and a cube peak; and b) the base of each cube is located within a range of 0 to 0.0127 millimeter (0.5 mil) from the neutral bending axis.
Claim 5
Dependent Claim
23 words
The retroreflective sheet of claim 1 in which the cube surfaces are located to create minimum peak to valley optical path difference values.
Claim 6
Dependent Claim
38 words
The retroreflective sheet of claim 1 in which: a) each reflective cube comprises a cube base and a cube peak; and b) the cube base is located closer to the neutral bending axis than is the cube peak.
Claim 7
Dependent Claim
52 words
The retroreflective sheet of claim 1 in which: a) each reflective cube comprises a cube base and a cube peak; and b) the value of the ratio of the distances of the cube base to the neutral bending axis and the cube base to the cube peak is between 0 and 0.5.
Claim 8
Dependent Claim
18 words
The retroreflective sheet of claim 6 in which the value of the ratio is between 0.2 and 0.3.
Claim 9
Dependent Claim
118 words
A layered retroreflective cube corner element article for bending applications, comprising: a) an article outer surface designed for tension during article bending and an article inner surface designed for compression during article bending; b) a neutral bending axis region located relative to the outer surface and the inner surface so that the neutral bending axis region comprises a neutral bending axis which is substantially free of stress and deformation during article bending; and c) a plurality of reflective cubes positioned between the outer surface and the inner surface, the cubes each having surfaces purposefully located proximate the neutral bending axis to reduce strain energy density on the reflective cubes and to enhance the optical performance of the article.
Claim 10
Dependent Claim
118 words
A layered retroreflective cube corner element article for bending applications, comprising: a) an article outer surface designed for tension during article bending and an article inner surface designed for compression during article bending; b) a neutral bending axis region located relative to the outer surface and the inner surface so that the neutral bending axis region comprises a neutral bending axis which is substantially free of stress and deformation during article bending; and c) a plurality of reflective cubes positioned between the outer surface and the inner surface, the cubes each having surfaces purposefully located proximate the neutral bending axis to reduce strain energy density on the reflective cubes and to enhance the optical performance of the article.
Claim 11
Dependent Claim
35 words
The retroreflective article of claim 8 in which the reflective cubes are positioned sufficiently close to the neutral bending axis to exhibit a normalized strain energy density value of less than about 1×10 -6 .
Claim 12
Dependent Claim
37 words
The retroreflective article of claim 8 in which the reflective cubes are positioned sufficiently close to the neutral bending axis to exhibit a normalized strain energy density value of between about 1×10 -6 and 1×10 -5 .
Claim 13
Dependent Claim
38 words
The retroreflective article of claim 8 in which: a) each reflective cube comprises a cube base and a cube peak; and b) the cube base is located closer to the neutral bending axis than is the cube peak.
Claim 14
Dependent Claim
52 words
The retroreflective article of claim 8 in which: a) each reflective cube comprises a cube base and a cube peak; and b) the value of the ratio of the distances of the cube base to the neutral bending axis and the cube base to the cube peak is between 0 and 0.5.
Claim 15
Dependent Claim
18 words
The retroreflective article of claim 12 in which the value of the ratio is between 0.2 and 0.3.
Claim 16
Dependent Claim
45 words
The retroreflective article of claim 8 in which: a) each reflective cube comprises a cube base and a cube peak; and b) the base of each reflective cube is located within a range of 0 to 0.0254 millimeter (1 mil) from the neutral bending axis.
Claim 17
Dependent Claim
44 words
The retroreflective article of claim 8 in which: a) each reflective cube comprises a cube base and a cube peak; and b) the base of each cube is located within a range of 0 to 0.0127 millimeter (0.5 mil) from the neutral bending axis.
Claim 18
Independent Claim
93 words
A method of manufacturing a retroreflective cube corner element laminated sheet for bending applications, comprising the steps of: a) providing a sheet with an outer surface designed for tension during laminated sheet bending and a sheet inner surface designed for compression during laminated sheet bending; and, b) positioning a plurality of reflective cubes within the sheet, each cube having a cube base and a cube peak; the plurality of cubes being positioned intentionally proximate to a neutral bending axis of the sheet to create optimal retroreflective performance for a given radius of curvature.
Claim 19
Independent Claim
93 words
A method of manufacturing a retroreflective cube corner element laminated sheet for bending applications, comprising the steps of: a) providing a sheet with an outer surface designed for tension during laminated sheet bending and a sheet inner surface designed for compression during laminated sheet bending; and, b) positioning a plurality of reflective cubes within the sheet, each cube having a cube base and a cube peak; the plurality of cubes being positioned intentionally proximate to a neutral bending axis of the sheet to create optimal retroreflective performance for a given radius of curvature.
Claim 20
Dependent Claim
31 words
The method according to claim 16 in which the base of each reflective cube is positioned within a range of 0 to 0.0254 millimeter (1.0 mil) from the neutral bending axis.
Claim 21
Dependent Claim
31 words
The method according to claim 16 in which the base of each reflective cube is positioned within a range of 0 to 0.0127 millimeter (0.5 mil) from the neutral bending axis.
Claim 22
Dependent Claim
35 words
The method according to claim 16 in which the reflective cubes are positioned sufficiently close to the neutral bending axis to exhibit a normalized strain energy density value of less than about 1×10 -6 .
Claim 23
Dependent Claim
37 words
The method according to claim 17 in which the reflective cubes are positioned sufficiently close to the neutral bending axis to exhibit a normalized strain energy density value of between about 1×10 -6 and 1×10 -5 .
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-02-23 | 1996-08-24 | 1997-02-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-02-23 | 2000-08-24 | 2001-02-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-02-23 | 2004-08-24 | 2005-02-23 | $7700.00 | Window Closed / Lapsed |