Patent US2987705A successfully refreshed from Google Patents.
US3894791A
Expired / Lapsed
US
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Reflective material for road marking and signs
Assignee: 3M Co
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Filing: 1974-11-11
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Granted: 1975-07-15
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Expires: 1994-11-11
Abstract
Abstract The disclosure describes a reflective material consisting of a plurality of double focusing reflex-reflective elements, wherein each element comprises an uncoated transparent core sphere having a part exposed to impinging light, a plurality of at least partially coated minor spheres or spherical bowls, the coating having reflective properties, arranged about the not exposed part of said core sphere, and a transparent binder or matrix between said core and minor spheres or bowls, whereby light beams impinging on said exposed part are subject to multiple refractive and reflective phenomena to improve the optical response by the element at any direction of light impingement.
Inventors
- 👤 Ludwig Eigenmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 17:46
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/12; G02B5/126; G02B5/128; E; E01; E01F; E01F9/00; E01F9/50; E01F9/506; E01F9/524
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
220 words
A reflecting system, comprising at least one substantially transparent, substantially spherical element having a refractive index such that a beam impinging said element is refracted and at least partially focused regardless of the angle of impingement; a substantially transparent binding medium contacting and partially surrounding said element so that a portion of said element is exposed for impingement by beams and a portion of said element is surrounded by said binding medium; and reflecting means for the reflection of beams which pass through said element, said reflecting means consisting at least almost entirely of reflective, substantially part-spherical surfaces which are convex in relation to said element and which are secured about the periphery of said surrounded portion thereof by said binding medium, said reflective surfaces being spaced from said surrounded portion of said element by said binding medium and having their respective centers of curvature located substantially at the virtual foci of the beams which pass through said exposed portion of said element into the latter and then through said binding medium to said reflective surfaces so that such beams are at least partially focused once more and are reflected back to said element and out through said exposed portion along paths essentially coincident with their respective paths of impingement upon and travel through said element and said binding medium.
Claim 2
Dependent Claim
220 words
A reflecting system, comprising at least one substantially transparent, substantially spherical element having a refractive index such that a beam impinging said element is refracted and at least partially focused regardless of the angle of impingement; a substantially transparent binding medium contacting and partially surrounding said element so that a portion of said element is exposed for impingement by beams and a portion of said element is surrounded by said binding medium; and reflecting means for the reflection of beams which pass through said element, said reflecting means consisting at least almost entirely of reflective, substantially part-spherical surfaces which are convex in relation to said element and which are secured about the periphery of said surrounded portion thereof by said binding medium, said reflective surfaces being spaced from said surrounded portion of said element by said binding medium and having their respective centers of curvature located substantially at the virtual foci of the beams which pass through said exposed portion of said element into the latter and then through said binding medium to said reflective surfaces so that such beams are at least partially focused once more and are reflected back to said element and out through said exposed portion along paths essentially coincident with their respective paths of impingement upon and travel through said element and said binding medium.
Claim 3
Dependent Claim
19 words
The reflecting system of claim 1, wherein said binding medium has a refractive index of at most about 1.5.
Claim 4
Dependent Claim
31 words
The reflecting system of claim 1, wherein the ratio of the radii of at least some of said reflective surfaces to the radius of said element are at most about 1:5.
Claim 5
Dependent Claim
31 words
The reflecting system of claim 1, wherein the ratios of the radii of at least some of said reflective surfaces to the radius of said element are between 1:10 and 1:100.
Claim 6
Dependent Claim
18 words
The reflecting system of claim 1, wherein said element has a diameter of about 0.25 to 10 millimeters.
Claim 7
Dependent Claim
15 words
The reflecting system of claim 5, wherein said diameter is about 0.4 to 2 millimeters.
Claim 8
Dependent Claim
50 words
The reflecting system of claim 1; further comprising a plurality of substantially transparent, substantially spherical elements arranged about said surrounded portion of said element; and wherein at least some of said reflective surfaces are constituted by reflective material arranged substantially concentrically with at least some of said plurality of elements.
Claim 9
Dependent Claim
23 words
The reflecting system of claim 7, wherein at least some of said plurality of elements have a refractive index of at least 1.9.
Claim 10
Dependent Claim
67 words
The reflecting system of claim 7, wherein said reflective material is in the form of coatings provided on said some of said plurality of elements; and further comprising additional substantially transparent, substantially spherical elements at least partially embedded in said binding medium and arranged so that interspaces are formed between adjacent ones of the same, at least some of said coated elements being arranged in said interspaces.
Claim 11
Dependent Claim
37 words
The reflecting system of claim 9, wherein the ratio of the radii of at least some of said additional elements to the radii of at least some of said coated elements are between about 10:1 and 100:1.
Claim 12
Dependent Claim
19 words
The reflecting system of claim 7, wherein At least some of said plurality of elements are composed of glass.
Claim 13
Dependent Claim
38 words
The reflecting system of claim 1, wherein at least some of said reflective surfaces comprise bowls formed in said binding medium and a layer of said binding medium separates said bowls from said element by a predetermined distance.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-07-14 | 1979-01-13 | 1979-07-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-14 | 1983-01-13 | 1983-07-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-14 | 1987-01-13 | 1987-07-15 | $7700.00 | Window Closed / Lapsed |