Patent US2054817A successfully refreshed from Google Patents.
US3919031A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Retroreflective film
Assignee: Rohm and Haas Co
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Filing: 1974-12-23
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Granted: 1975-11-11
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Expires: 1994-12-23
Abstract
Abstract A retroreflective film comprising a lamination of a first base layer having vacuum metallized hemispherical depressions on one surface thereof and a second layer having substantially hemispherical projections from the surface thereof formed from an optically transparent film wherein the first and second layers are arranged so that the hemispherical depressions of the base layer and the substantially hemispherical projections of the intermediate layer are concentrically arranged and the radius of the hemispherical depressions of the base layer is greater than the radius of the substantially hemispherical projections of the second layer. A laminates construction with matched opposing substantially hemispherical projections on the second layer is preferably provided with a third optically clear overlay film.
Inventors
- 👤 Michael L White
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 23:01
CPC Classifications
G; G02; G02B; G02B5/00; G02B5/12; G02B5/126; G02B5/128; Y; Y10; Y10T; Y10T156/00; Y10T156/10; Y10T156/1002; Y10T156/1039
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
147 words
A method for forming a retroreflective film comprising embossing the first film with hemispherical depressions on one surface thereof, vacuum metallizing said embossed surface of said first film, embossing a second optically transparent film between a pair of matched, opposed synchronized engraving means to form matched opposing substantially hemispherical projections from each surface of said second film, wherein said projections have an identical centerto-center spacing but a smaller radius than that of the hemispherical depressions of the first film, arranging the substantially hemispherical projections of one surface of said second film concentrically with the hemispherical depressions of the first film, providing a third optically clear film layer making tangential contact with the substantially hemispherical projections from a surface of the second film, with means laminating said film layers whereby inactivation of optical properties is maintained at about 20% or less of the total area of the laminate.
Claim 2
Independent Claim
147 words
A method for forming a retroreflective film comprising embossing the first film with hemispherical depressions on one surface thereof, vacuum metallizing said embossed surface of said first film, embossing a second optically transparent film between a pair of matched, opposed synchronized engraving means to form matched opposing substantially hemispherical projections from each surface of said second film, wherein said projections have an identical centerto-center spacing but a smaller radius than that of the hemispherical depressions of the first film, arranging the substantially hemispherical projections of one surface of said second film concentrically with the hemispherical depressions of the first film, providing a third optically clear film layer making tangential contact with the substantially hemispherical projections from a surface of the second film, with means laminating said film layers whereby inactivation of optical properties is maintained at about 20% or less of the total area of the laminate.
Claim 3
Dependent Claim
94 words
A METTHOD FOR FORMING A RETROFLECTIVE FILM COMPRISING EMBOSSING THE FIRST FILM WITH HEMISPHERICAL DEPRESSIONS ON ONE SURFACE THEREOF, VACUUM METALLIZING SAID EMBOSSED SURFACE OF SAID FIRST, EMBOSSING A SECCOND OPTICALLY TRANSPARENT FILM WITH SUBSTANTIALLY HEMISPHERICAL PROTECTIONS CORM THE SURFACE THEREOF, WHEREIN SAID PROJECTIONS HAVE AN IDENTICAL CENTER-TO CENTER SPACING, BUT A SMALLER RADIOUS THAN THAT OF THE HEMISPHERICAL DEPRESSIONS OF THE FIRST FILM, ARRANGING THE SUBSTANTIALLY HEMISPHERICAL PROJECTIONS OF THE SECOND FILM ONCENTRICALLY WITH THE HEMISPHERICAL DEPRESSIONS OF THE FIRST FILM, WITH MEANS LAMINTING SAID FILM LAYERS WHEREBY NO OPTICAL DISORTION IS CREATED.
Claim 4
Dependent Claim
94 words
A METTHOD FOR FORMING A RETROFLECTIVE FILM COMPRISING EMBOSSING THE FIRST FILM WITH HEMISPHERICAL DEPRESSIONS ON ONE SURFACE THEREOF, VACUUM METALLIZING SAID EMBOSSED SURFACE OF SAID FIRST, EMBOSSING A SECCOND OPTICALLY TRANSPARENT FILM WITH SUBSTANTIALLY HEMISPHERICAL PROTECTIONS CORM THE SURFACE THEREOF, WHEREIN SAID PROJECTIONS HAVE AN IDENTICAL CENTER-TO CENTER SPACING, BUT A SMALLER RADIOUS THAN THAT OF THE HEMISPHERICAL DEPRESSIONS OF THE FIRST FILM, ARRANGING THE SUBSTANTIALLY HEMISPHERICAL PROJECTIONS OF THE SECOND FILM ONCENTRICALLY WITH THE HEMISPHERICAL DEPRESSIONS OF THE FIRST FILM, WITH MEANS LAMINTING SAID FILM LAYERS WHEREBY NO OPTICAL DISORTION IS CREATED.
Claim 5
Dependent Claim
58 words
The method of claim 1, whereiN the ratio h/R, where h is the distance between the reflecting metallized surface of the hemispherical depressions of the first film and the substantially hemispherical projections of the second film, and wherein R is the radius of the matched opposing substantially hemispherical projections of the second film, is defined by the equation:
Claim 6
Dependent Claim
56 words
The method of claim 2, wherein the ratio h/R where h is the distance between the reflecting metallized surface of the hemispherical depressions of the first film and the substantially hemispherical projections of the second film, and wherein R is the radius of the substantially hemispherical projections of the second film, is defined by the equation:
Claim 7
Dependent Claim
17 words
The method of claim 1, wherein the transparent films of the laminate are formed of acrylic plastics.
Claim 8
Dependent Claim
17 words
The method of claim 2, wherein the transparent films of the laminate are formed of acrylic plastics.
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) | 1978-11-10 | 1979-05-12 | 1979-11-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-11-10 | 1983-05-12 | 1983-11-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-11-10 | 1987-05-12 | 1987-11-11 | $7700.00 | Window Closed / Lapsed |