US4906070A
Expired / Lapsed
US
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Totally internally reflecting thin, flexible film
Assignee: 3M Innovative Properties Co
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Filing: 1988-07-12
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Granted: 1990-03-06
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Expires: 2008-07-12
Abstract
Abstract A thin, flexible film made of a transparent polymeric material including a structured surface and an opposite smooth surface, wherein light striking either surface, within certain angular ranges, is totally internally reflected. The structured surface includes a linear array of miniature substantially right angled isosceles prisms arranged side-by-side to form a plurality of peaks and grooves. In addition, the perpendicular sides of the prisms make an angle of approximately 45° with the smooth surface, and when the film is curled the smooth surface lies in a smooth continuous arcuate curve without materially affecting the performance of the film. Because of the film's flexibility and its ability to totally internally reflect light, it may be utilized in a variety of ways, for example, as a collector of solar energy or as a light conduit. The performance of the film may be manipulated to permit controlled light leakage.
Inventors
- 👤 Sanford Cobb, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 10:56
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/10; F; F21; F21V; F21V5/00; F21V5/002; F24; F24S; F24S23/00; F24S23/10; G02B5/00; G02B5/12; F21V2200/00; F21V2200/40; G02B6/24; G02B6/36; G02B6/38; G02B6/3807; Y; Y02; Y02E; Y02E10/00; Y02E10/40
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
101 words
A thin, flexible film of a transparent polymeric material, comprising a structured surface on one side and a smooth surface opposite said structured surface on the other side, wherein said structured surface includes a linear array of miniature isosceles prisms having substantially perpendicular sides arranged side-by-side to form a plurality of peaks and grooves, the perpendicular sides of said prisms make an angle of approximately 45° with said smooth surface opposite said structured surface, said film being capable of being curled such that said smooth surface lies in a smooth continuous arcuate curve having a diameter of less than 3 inches.
Claim 2
Dependent Claim
101 words
A thin, flexible film of a transparent polymeric material, comprising a structured surface on one side and a smooth surface opposite said structured surface on the other side, wherein said structured surface includes a linear array of miniature isosceles prisms having substantially perpendicular sides arranged side-by-side to form a plurality of peaks and grooves, the perpendicular sides of said prisms make an angle of approximately 45° with said smooth surface opposite said structured surface, said film being capable of being curled such that said smooth surface lies in a smooth continuous arcuate curve having a diameter of less than 3 inches.
Claim 3
Dependent Claim
19 words
The film defined in claim 1, wherein said isosceles prisms are micro in size, at least 40 per inch.
Claim 4
Dependent Claim
17 words
The film defined in claim 1, wherein the film does not have sufficient strength to be self-supporting.
Claim 5
Dependent Claim
13 words
The film defined in claim 1, wherein said transparent polymeric material is polycarbonate.
Claim 6
Dependent Claim
13 words
The film defined in claim 1, wherein said transparent polymeric material is acrylic.
Claim 7
Dependent Claim
21 words
The film defined in claim 1, wherein incident light striking the smooth surface within certain angular ranges is totally internally reflected.
Claim 8
Dependent Claim
21 words
The film defined in claim 1, wherein incident light striking the structured surface within certain angular ranges is totally internally reflected.
Claim 9
Dependent Claim
45 words
The film defined in claim 1, wherein said film has a thickness of approximately 0.015 of an inch and about 70 prisms per inch so that when said film is curled said smooth surface lies in a smooth continuous arcuate curve without any discernible discontinuities.
Claim 10
Dependent Claim
120 words
A light conduit for transporting light, comprising a thin, flexible film of a transparent polymeric material including a structured surface on one side and a smooth surface opposite said structured surface on the other side, said structured surface having a linear array of miniature isosceles prisms having substantially perpendicular sides arranged side-by-side to form a plurality of peaks and grooves, the perpendicular sides of said prisms make an angle of approximately 45° with said smooth surface opposite said structured surface, and said film is formed into a tubular configuration so that said smooth surface lies in a smooth continuous arcuate curve, whereby light entering the conduit, within certain angular ranges, is totally internally reflected as it travels along the conduit.
Claim 11
Dependent Claim
120 words
A light conduit for transporting light, comprising a thin, flexible film of a transparent polymeric material including a structured surface on one side and a smooth surface opposite said structured surface on the other side, said structured surface having a linear array of miniature isosceles prisms having substantially perpendicular sides arranged side-by-side to form a plurality of peaks and grooves, the perpendicular sides of said prisms make an angle of approximately 45° with said smooth surface opposite said structured surface, and said film is formed into a tubular configuration so that said smooth surface lies in a smooth continuous arcuate curve, whereby light entering the conduit, within certain angular ranges, is totally internally reflected as it travels along the conduit.
Claim 12
Dependent Claim
49 words
The light conduit defined in claim 9, wherein the corners of said prisms of said structured surface are not optically sharp, so that the light conduit acts as an illuminator by allowing some of the light entering said conduit to escape through the film without being totally internally reflected.
Claim 13
Dependent Claim
50 words
The light conduit defined in claim 9, wherein the perpendicular sides of said prisms of said structured surface are not optically smooth, so that the light conduit acts as an illuminator by allowing some of the light entering said conduit to escape through the film without being totally internally reflected.
Claim 14
Dependent Claim
40 words
The light conduit defined in claim 9, wherein said peaks are rounded to permit controlled light leakage defined in accordance with the ratio r/ρ, where r is the approximate radius of the round peaks and ρ is the groove period.
Claim 15
Dependent Claim
132 words
A thin, flexible film of a transparent polymeric material, comprising a structured surface on one side and a smooth surface opposite said structured surface on the other side, said structured surface includes a linear array of miniature isoceles prisms having substantially perpendicular sides arranged side-by-side to form a plurality of peaks and grooves, the perpendicular sides of said prisms make an angle of approximately 45° with said smooth surface opposite said structured surface, said film being capable of being curled such that said smooth surface lies in a smooth continuous arcuate curve having a diameter of less than 18 inches wherein said peaks are rounded to permit controlled light leakage in accordance with the ratio r/ρ where r is the approximate radius of the round peaks and ρ is the groove period.
Claim 16
Dependent Claim
132 words
A thin, flexible film of a transparent polymeric material, comprising a structured surface on one side and a smooth surface opposite said structured surface on the other side, said structured surface includes a linear array of miniature isoceles prisms having substantially perpendicular sides arranged side-by-side to form a plurality of peaks and grooves, the perpendicular sides of said prisms make an angle of approximately 45° with said smooth surface opposite said structured surface, said film being capable of being curled such that said smooth surface lies in a smooth continuous arcuate curve having a diameter of less than 18 inches wherein said peaks are rounded to permit controlled light leakage in accordance with the ratio r/ρ where r is the approximate radius of the round peaks and ρ is the groove period.
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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) | 1993-03-05 | 1993-09-04 | 1994-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-03-05 | 1997-09-04 | 1998-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-03-05 | 2001-09-04 | 2002-03-06 | $7700.00 | Window Closed / Lapsed |