Patent US4895428A successfully refreshed from Google Patents.
US4895428A
Expired / Lapsed
US
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High efficiency retroreflective material
Assignee: 3M Co
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Filing: 1988-07-26
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Granted: 1990-01-23
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Expires: 2008-07-26
Abstract
Abstract The present invention provides a retroreflective material which has improved retroreflectivity at high angles of incidence. The retroreflective material comprises a transparent surface layer and an array of reflecting elements, each of the reflecting elements including a rectangular base having a length L, two tetragonal faces nearly perpendicular to each other and having a line of intersection of length Y, the length Y being less than said length L, a triangular face nearly perpendicular to the tetragonal faces; and a non-perpendicular triangular face forming an angle alpha with the plane perpendicular to the base, the angle alpha being preferably about sin -1 (0.25/n) to sin -1 (l/n), and more preferably about sin -1 (0.35/n) to sin -1 (0.9/n), where n is the refractive index of the reflecting elements, the perpendicular triangular face and the tetragonal face defining an approximate cube corner therebetween and the non-perpendicular triangular face and the tetragonal faces forming a non-orthogonal corner therebetween, the reflecting elements arranged with their base adjacent the surface layer.
Inventors
- 👤 John C. Nelson
- 👤 Sanford Cobb, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:17
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/04; G02B5/12; G02B5/122; G02B5/124; B; B29; B29C; B29C65/00; B29C65/02; B29C65/08; B29K; B29K2001/00; B29K2001/08; B29K2001/12; B29K2001/14; B29K2995/00; B29K2995/0018; B29K2995/003; Y; Y10; Y10T; Y10T428/00; Y10T428/24; Y10T428/24479; Y10T428/24521
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
137 words
A retroreflective material comprising a transparent surface layer and an array of reflecting elements, each of said reflecting elements including: (a) a rectangular base having a length L, (b) two mutually substantially perpendicular tetragonal faces having a line of intersection of length Y, said length Y being less than said length L, (c) a triangular face substantially perpendicular to said tetragonal faces; and (d) a non-perpendicular triangular face forming an angle alpha with a plane perpendicular to said base, said angle alpha being about sin -1 (0.25/n) to sin -1 (1/n), where n is the refractive index of the reflecting elements; said triangular face and tetragonal faces defining a cube corner therebetween and said non-perpendicular triangular face and said tetragonal faces forming a non-orthogonal corner therebetween, said reflecting elements arranged with their bases adjacent said surface layer.
Claim 2
Dependent Claim
137 words
A retroreflective material comprising a transparent surface layer and an array of reflecting elements, each of said reflecting elements including: (a) a rectangular base having a length L, (b) two mutually substantially perpendicular tetragonal faces having a line of intersection of length Y, said length Y being less than said length L, (c) a triangular face substantially perpendicular to said tetragonal faces; and (d) a non-perpendicular triangular face forming an angle alpha with a plane perpendicular to said base, said angle alpha being about sin -1 (0.25/n) to sin -1 (1/n), where n is the refractive index of the reflecting elements; said triangular face and tetragonal faces defining a cube corner therebetween and said non-perpendicular triangular face and said tetragonal faces forming a non-orthogonal corner therebetween, said reflecting elements arranged with their bases adjacent said surface layer.
Claim 3
Dependent Claim
11 words
The retroreflective material of claim 1 wherein n is about 1.4-1.6.
Claim 4
Dependent Claim
19 words
The retroreflective material of claim 1 wherein said angle alpha is about sin -1 (0.35/n) to sin -1 (0.9/n).
Claim 5
Dependent Claim
17 words
The retroflective material of claim 1 wherein said tetragonal faces meet said base at substantially 45° angles.
Claim 6
Dependent Claim
13 words
The retroflective material of claim 1 wherein said reflecting elements are uniformly arranged.
Claim 7
Dependent Claim
16 words
The retroreflective material of claim 5 wherein the reflecting elements are arranged in rows and columns.
Claim 8
Dependent Claim
35 words
The retroreflective material of claim 6 in which the non-perpendicular faces in one column of reflectinhg elements and the substantially perpendicular triangular faces on the adjacent column of reflective elements share a common base line.
Claim 9
Dependent Claim
30 words
The retroreflective material of claim 7 in which tetragonal faces in one row of reflective elements and those in the adjacent row of reflective elements share a common base line.
Claim 10
Dependent Claim
28 words
The retroreflective material of claim 8 wherein the spacing between the lines Y of reflective elements in adjacent rows is twice the depth, D, of the reflective elements.
Claim 11
Dependent Claim
12 words
The retroreflective material of claim 1 wherein said reflecting elements are metallized.
Claim 12
Dependent Claim
26 words
The retroreflective material of claim 1 wherein said reflective elements have a depth, D, wherein D is about 0.02-10 millimeters, and L is about twice Y.
Claim 13
Dependent Claim
49 words
The retroreflective material of claim 1 further including canted bisector reflective elements each having a bisector of the angle of intersection of said mutually perpendicular tetragonal faces which intersects said base, said bisectors forming an angle, Beta with a line perpendicular with said base, wherein Beta is about 5°-45°.
Claim 14
Dependent Claim
13 words
The reteroreflective material of claim 12 wherein said angle Beta is about 5°-15°.
Claim 15
Dependent Claim
20 words
The retroreflective material of claim 12 wherein Beta is the same angle for each of said canted bisector reflective elements.
Claim 16
Dependent Claim
16 words
The retroreflective material of claim 12 wherein Beta varies randomly for said canted bisector reflective elements.
Claim 17
Dependent Claim
19 words
The retroreflective material of claim 12 wherein Beta varies in a uniform pattern for said canted bisector reflective elements.
Claim 18
Dependent Claim
11 words
The retroreflective material of claim 1 further including a backing layer.
Claim 19
Dependent Claim
18 words
The retroreflective material of claim 17 wherein said cube corners and non-orthogonal corners are adjacent said backing layer.
Claim 20
Dependent Claim
195 words
A retroreflective material comprising a transparent surface layer and an array of reflecting elements, each of said reflecting elements including: (a) a rectangular base having a length L, (b) two tetragonal faces nearly perpendicular to each other having a line of intersection of length Y, said length Y being less than said length L, (c) a triangular face nearly perpendicular to said tetragonal faces; and (d) a non-perpendicular triangular face forming an angle alpha with a plane perpendicular to said base, said angle alpha being about sin -1 (0.25/n) to sin -1 (1/n), wherein n is the refractive index of the reflecting elements; said triangular face and tetragonal faces defining a cube corner therebetween and said non-perpendicular triangular face and said tetragonal faces forming a non-orthogonal corner therebetween, said reflecting elements arranged with their bases adjacent said surface layer; wherein said reflecting elements are formed by two perpendicular intersecting sets of parallel grooves, a first set of V-shaped grooves, each having a first and second face and a second set of grooves, each having a third face nearly perpendicular to the surface layer and a fourth face which is not perpendicular to the surface layer.
Claim 21
Dependent Claim
195 words
A retroreflective material comprising a transparent surface layer and an array of reflecting elements, each of said reflecting elements including: (a) a rectangular base having a length L, (b) two tetragonal faces nearly perpendicular to each other having a line of intersection of length Y, said length Y being less than said length L, (c) a triangular face nearly perpendicular to said tetragonal faces; and (d) a non-perpendicular triangular face forming an angle alpha with a plane perpendicular to said base, said angle alpha being about sin -1 (0.25/n) to sin -1 (1/n), wherein n is the refractive index of the reflecting elements; said triangular face and tetragonal faces defining a cube corner therebetween and said non-perpendicular triangular face and said tetragonal faces forming a non-orthogonal corner therebetween, said reflecting elements arranged with their bases adjacent said surface layer; wherein said reflecting elements are formed by two perpendicular intersecting sets of parallel grooves, a first set of V-shaped grooves, each having a first and second face and a second set of grooves, each having a third face nearly perpendicular to the surface layer and a fourth face which is not perpendicular to the surface layer.
Claim 22
Dependent Claim
42 words
The retroreflective material of claim 19 in which at least one of said first, second, and third sets of faces includes, in a repeating pattern, at least one groove side angle that differs from another groove side angle of the same set.
Claim 23
Dependent Claim
11 words
The retroreflective material of claim 19 wherein n is about 1.4-1.6.
Claim 24
Dependent Claim
19 words
The retroreflective material of claim 19 wherein said angle alpha is about sin -1 (0.35/n) to sin -1 (0.9/n).
Claim 25
Dependent Claim
124 words
A retroreflective material comprising a transparent surface layer and an array of reflecting elements, each of said reflecting elements including: (a) a rectangular base having a length L, (b) two mutually substantially perpendicular tetragonal faces having a line of intersection of length Y, said length Y being less than said length L, (c) a triangular face substantially perpendicular to said tetragonal faces; and (d) a non-perpendicular triangular face forming an angle alpha with a plane perpendicular to said base, said angle alpha being in the range of 6°-65°; said triangular face and tetragonal faces defining a cube corner therebetween and said non-perpendicular triangular face and said tetragonal faces forming a non-orthogonal corner therebetween, said reflecting elements arranged with their bases adjacent said surface layer.
Claim 26
Dependent Claim
124 words
A retroreflective material comprising a transparent surface layer and an array of reflecting elements, each of said reflecting elements including: (a) a rectangular base having a length L, (b) two mutually substantially perpendicular tetragonal faces having a line of intersection of length Y, said length Y being less than said length L, (c) a triangular face substantially perpendicular to said tetragonal faces; and (d) a non-perpendicular triangular face forming an angle alpha with a plane perpendicular to said base, said angle alpha being in the range of 6°-65°; said triangular face and tetragonal faces defining a cube corner therebetween and said non-perpendicular triangular face and said tetragonal faces forming a non-orthogonal corner therebetween, said reflecting elements arranged with their bases adjacent said surface layer.
Claim 27
Dependent Claim
13 words
The retroreflective material of claim 23 wherein said reflecting elements are uniformly arranged.
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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) | 1993-01-22 | 1993-07-24 | 1994-01-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-01-22 | 1997-07-24 | 1998-01-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-01-22 | 2001-07-24 | 2002-01-23 | $7700.00 | Window Closed / Lapsed |