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US 4,906,070 AGranted
Totally internally reflecting thin, flexible film
AssigneeMinnesota Mining and Manufacturing Company
InventorSanford Cobb, Jr.
Life of this patent
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AssigneeMinnesota Mining and Manufacturing Company
InventorSanford Cobb, Jr.
Estimating the term…
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.degree. 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.
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.degree. 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.
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.degree. 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.
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.degree. 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/.rho. where r is the approximate radius of the round peaks and .rho. is the groove period.
Dependencies are inferred from the claim text.