EP0269329A2
Expired / Lapsed
EP
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Cube-corner retroreflective articles having tailored divergence profiles
Assignee: 3M Co
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Filing: 1987-11-13
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Granted: —
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Expires: 2007-11-13
Abstract
Abstract Cube-corner retroreflective article in which the cube-corner retroreflective elements are formed by three intersecting sets of parallel V-shaped grooves (11, 12, 13), at least one of the sets (13) including, in a repeating pattern, at least one groove side angle (13₂, 13₃, 13₄) that differs from another groove side angle (13₁) of the same set. By the described variation in groove side angle, the array of cube-corner retroreflective elements is divided into repeating sub-arrays that each comprise a plurality of cube-corner retroreflective elements in a plurality of distinctive shapes that retroreflect incident light in distinctively shaped light patterns.
Inventors
- 👤 Roger H. C/O Minnesota Mining And Appeldorn
- 👤 John C. C/O Minnesota Mining And Nelson
- 👤 Mark E. C/O Minnesota Mining And Gardiner
- 👤 Timothy L. C/O Minnesota Mining And Hoopman
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 13:05
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/12; G02B5/122; G02B5/124
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
98 words
Retroreflective article which carries on one side an array of cube-corner retroreflective elements, the three lateral reflecting faces of the elements being formed by three intersecting sets of parallel V-shaped groove characterized in that at least one of the sets includes, in a repeating pattern, at least one groove side angle that differs from another groove side angle of the same set, whereby the array of cube-corner retroreflective elements is divided into repeating sub-arrays that each comprise a plurality of cube-corner retroreflective elements in a plurality of distinctive shapes that retroreflect incident light in distinctively shaped light patterns.
Claim 2
Dependent Claim
98 words
Retroreflective article which carries on one side an array of cube-corner retroreflective elements, the three lateral reflecting faces of the elements being formed by three intersecting sets of parallel V-shaped groove characterized in that at least one of the sets includes, in a repeating pattern, at least one groove side angle that differs from another groove side angle of the same set, whereby the array of cube-corner retroreflective elements is divided into repeating sub-arrays that each comprise a plurality of cube-corner retroreflective elements in a plurality of distinctive shapes that retroreflect incident light in distinctively shaped light patterns.
Claim 3
Dependent Claim
36 words
Retroreflective article of claim 1 in which at least two of the sets of V-shaped grooves include, in a repeating pattern, a groove side angle that differs from another groove side angle of the same set.
Claim 4
Dependent Claim
33 words
Retroreflective article of claim 1 in which all three sets of V-shaped grooves include, in a repeating pattern, a groove side angle that differs from another groove side angle of the same set.
Claim 5
Dependent Claim
51 words
Retroreflective article of any of claims 1-3 in which said at least one set of grooves includes in a repeating pattern at least two different groove side angles that differ from the angle needed for all dihedral angles of cube-corner retroreflective elements defined by those groove side angles to be orthogonal.
Claim 6
Dependent Claim
48 words
Retroreflective article of any of claims 1-3 in which substantially all of the groove side angles in the repeating pattern of said at least one set differ from the angle needed for all dihedral angles of cube-corner retroreflective elements defined by those groove side angles to be orthogonal.
Claim 7
Dependent Claim
44 words
Retroreflective article of any of claims 1-5 in which the cube-corner retroreflective elements of the array of elements are arranged in pairs of elements, so that each distinctively shaped element is matched by a similarly shaped element rotated 180 degrees from the first element.
Claim 8
Dependent Claim
31 words
Retroreflective article of any of claims 1-6 in which the pattern of at least one set includes an a-b-b-a pattern, where "a" and "b" are each a different groove side angle.
Claim 9
Dependent Claim
91 words
Retroreflective article of any of claims 1-7 in which the potential number (N u ) of different cube-corner retroreflective elements in a sub-array as determined by the equation N u = 2(mno/F), where m, n, and o are the number of grooves in a repeating pattern in the three respective sets of grooves, and F is the largest single whole number factor that can be divided evenly into each of the individual numbers m, n, and o, is less than the possible number of combinations (C) calculated from C = 2(mno).
Claim 10
Dependent Claim
18 words
Retroreflective article of any of claims 1-7 which exhibits a Design Efficiency Factor of at least 25 percent.
Claim 11
Dependent Claim
37 words
Retroreflective article of any of claims 1-9 in which the cube-corner retroreflective elements are chosen so as to concentrate more reflected light into certain regions of the divergence profile of the retroreflective article than in other regions.
Claim 12
Dependent Claim
21 words
Retroreflective article of any of claims 1-10 from which 0°-entrance-angle light is retroreflected with a profile as shown in Figure 9.
Claim 13
Dependent Claim
75 words
Retroreflective article of any of claims 1-11 in the form of a traffic control sign in which the summation of the different light patterns in which the different cube-corner retroreflective elements in a sub-array retroreflect incident light produces an overall retroreflective divergence profile that more closely matches the expected observation profile for the sign than would the retroreflective divergence profile from an article in which all the cube-corner retroreflective elements of said array are identical.
Claim 14
Dependent Claim
68 words
Retroreflective article of any of claims 1-12 made from tooling that was prepared by grooving a planar surface that comprised a bundle of individual pins, the portion of the planar surface formed by each pin being at least as large in area as the area of an individual sub-array, with at least some of the pins being rotated after the grooving operation was completed and then reassembled together.
Claim 15
Dependent Claim
37 words
Retroreflective article of any of claims 1-13 in which the optical axes of at least some of the cube-corner retroreflective elements are tilted toward one edge of that element to increase the entrance angularity of the article.
Claim 16
Dependent Claim
48 words
Retroreflective article of any of claims 1-14 in which the summation of the distinctively shaped light patterns produces an overall retroreflective light pattern that has greater rotational symmetry than the retroreflective light pattern from an article in which all the cube-corner retroreflective elements of said array are identical.
Claim 17
Dependent Claim
58 words
Retroreflective article of any of claims 1-15 in which at least one groove side angle in at least one set of grooves exceeds, and at least one other groove side angle of the same set of grooves is less than, the angle that would produce an orthogonal intersection with other faces of elements defined by those groove sides.
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