US3781083A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Light reflecting system
Assignee: 3M Co
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Filing: 1972-07-10
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Granted: 1973-12-25
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Expires: 1992-07-10
Abstract
Abstract The disclosure describes an optical system adapted for providing road signs and markers and the like, and capable of reflecting incident light in essentially the same direction as that of incidence, regardless of the angle of incidence. The system comprises a primary surface layer of transparent spheres positioned to be impinged by light beams and capable of primarily focusing the light impinging thereon, a secondary lower layer comprising minor transparent spheres individually arranged for secondarily focusing of the light issued by the first spheres and located at different distances from the respective adjacent first sphere, and a sheet of reflective material having embossed concavities individually positioned adjacent to each minor sphere for reflecting the secondarily focused light, the spheres being at least partially embedded in a transparent bonding layer the index of refraction of which is lower than that of the spheres.
Inventors
- 👤 L Eigenmann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 17:40
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: 9
Claim 1
Independent Claim
284 words
A light reflecting system, comprising a transparent binder material; a plurality of closely arranged transparent first spheres embedded in said binder material and forming a substantially planar first layer therein, each of said first spheres having an exposed portion adapted to be impinged by light beams, and said first spheres refracting and focusing the light beams impinging said exposed portions so as to cause convergence of the light rays constituting the light beams; a second layer of transparent second spheres fully embedded in said binder material and substantially paralleling said first layer and being tangent thereto, said second spheres having a size smaller than that of said first spheres and an index of refraction greater than that of said binder material, and said second spheres being arranged in such a manner that to each of said first spheres there corresponds a plurality of second spheres adapted to further focus the light beams which have passed through the corresponding first sphere, said plurality of second spheres being arrayed about the corresponding first sphere so that some of said plurality of second spheres are spaced from the corresponding first sphere by a greater distance than others of said plurality of second spheres, whereby the light beams impinging the exposed portion of the corresponding first sphere at larger angles of incidence are further focused by said some of said plurality of second spheres and the light beams impinging the exposed portion of the corresponding first sphere at smaller angles of incidence are further focused by said others of said plurality of second spheres; and reflective surfaces for reflecting the light beams which have passed through said second spheres, said reflective surfaces being concave towards said second spheres.
Claim 2
Dependent Claim
284 words
A light reflecting system, comprising a transparent binder material; a plurality of closely arranged transparent first spheres embedded in said binder material and forming a substantially planar first layer therein, each of said first spheres having an exposed portion adapted to be impinged by light beams, and said first spheres refracting and focusing the light beams impinging said exposed portions so as to cause convergence of the light rays constituting the light beams; a second layer of transparent second spheres fully embedded in said binder material and substantially paralleling said first layer and being tangent thereto, said second spheres having a size smaller than that of said first spheres and an index of refraction greater than that of said binder material, and said second spheres being arranged in such a manner that to each of said first spheres there corresponds a plurality of second spheres adapted to further focus the light beams which have passed through the corresponding first sphere, said plurality of second spheres being arrayed about the corresponding first sphere so that some of said plurality of second spheres are spaced from the corresponding first sphere by a greater distance than others of said plurality of second spheres, whereby the light beams impinging the exposed portion of the corresponding first sphere at larger angles of incidence are further focused by said some of said plurality of second spheres and the light beams impinging the exposed portion of the corresponding first sphere at smaller angles of incidence are further focused by said others of said plurality of second spheres; and reflective surfaces for reflecting the light beams which have passed through said second spheres, said reflective surfaces being concave towards said second spheres.
Claim 3
Dependent Claim
18 words
A light reflecting system as defined in claim 1, wherein all of said spheres are made of glass.
Claim 4
Dependent Claim
41 words
A light reflecting system as defined in claim 1, wherein said reflective surfaces are constituted by a sheet of reflective metal positioned adjacent said second layer and embossed so as to define a reflective concavity for each of said second spheres.
Claim 5
Dependent Claim
83 words
A light reflecting system as defined in claim 1, wherein each of said first spheres has a major diameter substantially normal to said first layer, and said second layer comprises a plurality of concavities each of which corresponds to one of said first spheres and is coaxial with the major diameter thereof, the spacing between the second spheres within each concavity and the corresponding first sphere increasing with increasing distance of the second spheres from the major diameter of the corresponding first sphere.
Claim 6
Dependent Claim
26 words
A light reflecting system as defined in claim 1, wherein the index of refraction of said first spheres is greater than that of said binder material.
Claim 7
Dependent Claim
53 words
A light reflecting system as defined in claim 5, wherein the index of refraction of said first spheres lies between substantially 1.45 and 1.68, the index of refraction of said second spheres lies between substantially 1.70 and 2.05, and the index of refraction of said binder material lies between substantially 1.34 and 1.50.
Claim 8
Dependent Claim
28 words
A light reflecting system as defined in claim 1, wherein the diameter of sAid second spheres is at most equal to one-tenth the diameter of said first spheres.
Claim 9
Dependent Claim
35 words
A light reflecting system as defined in claim 1, wherein said first spheres have a diameter between substantially 200 and 1,200 microns, and said second spheres have a diameter between substantially 5 and 70 microns.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-12-24 | 1977-06-25 | 1977-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-24 | 1981-06-25 | 1981-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-24 | 1985-06-25 | 1985-12-25 | $7700.00 | Window Closed / Lapsed |