Low transmission heat-reflective glazing materials
First Claim
Patent Images
1. A heat-reflective glazing material comprising a transparent substrate having a surface and a composite film on the surface,the composite film having a single discrete layer consisting essentially of metallic silver of from 270Å
- to 400Å
in thickness disposed between two discrete layers of transparent dielectric, one a bottom layer located between the substrate and the silver layer and the other a top layer located on top of the silver layer,the bottom layer being at least about 30Å
in physical thickness and the top layer having an index of refraction at 550 nm of 1.75 to 2.50 and being from 950Å
to 1800Å
in optical thickness, the thickness of the dielectric layers being selected so as to yield a composite film having a total transmission of available solar energy in the visible wavelengths of 380-750 nm of less than 40% and a reflection of solar energy in all wavelengths of at least about 50% and a transmitted and reflected color neutrality such that the maximum transmission at any wavelength between 400Å and
700Å
(Tmax(400-700)) is not greater than 1.7 times the minimum transmission at any wavelength between 400Å and
700Å
(Tmin(400-700)) and the maximum reflectance at any wavelength between 400Å and
700Å
(Rmax(400-700)) is not greater than 1.7 times the minimum reflectance at any wavelength between 400Å and
700Å
(Rmin(400-700)), and absolute values for each of L*a*b* color space coordinates, Ta*, Tb*, Ra* and Rb* of less than 6.
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Abstract
High-performance heat-reflective films having a metallic silver layer bounded by two dielectric layers are disclosed. The thickness of the layers is selected to insure high levels of heat rejection but relatively high levels of light transmission together with a substantial level of color neutrality.
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Citations
21 Claims
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1. A heat-reflective glazing material comprising a transparent substrate having a surface and a composite film on the surface,
the composite film having a single discrete layer consisting essentially of metallic silver of from 270Å - to 400Å
in thickness disposed between two discrete layers of transparent dielectric, one a bottom layer located between the substrate and the silver layer and the other a top layer located on top of the silver layer,the bottom layer being at least about 30Å
in physical thickness and the top layer having an index of refraction at 550 nm of 1.75 to 2.50 and being from 950Å
to 1800Å
in optical thickness, the thickness of the dielectric layers being selected so as to yield a composite film having a total transmission of available solar energy in the visible wavelengths of 380-750 nm of less than 40% and a reflection of solar energy in all wavelengths of at least about 50% and a transmitted and reflected color neutrality such that the maximum transmission at any wavelength between 400Å and
700Å
(Tmax(400-700)) is not greater than 1.7 times the minimum transmission at any wavelength between 400Å and
700Å
(Tmin(400-700)) and the maximum reflectance at any wavelength between 400Å and
700Å
(Rmax(400-700)) is not greater than 1.7 times the minimum reflectance at any wavelength between 400Å and
700Å
(Rmin(400-700)), and absolute values for each of L*a*b* color space coordinates, Ta*, Tb*, Ra* and Rb* of less than 6. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
- to 400Å
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12. A solar sheet control glazing material comprising a sheet of clear float glass from about 1/8 inch thick through about 1/4 inch thick and having an outer solar-impacting surface and an inner surface having sputter-deposited on its inner surface a three-layer composite heat-reflective sputter-deposited film made up of a 290Å
- to 380Å
thick layer consisting essentially of silver deposited between a 30Å
to 1000Å
which transparent dielectric underlayer and a 500Å
to 950Å
which top layer of transparent dielectric having an index of refraction of from 1.75 to 2.50 and an optical thickness of from 950Å
to 1800Å
. - View Dependent Claims (13, 14, 15, 16)
- to 380Å
-
17. A heat-control glazing material comprising a flexible poly(ethylene terephthalate) film of from 0.5 to 3 mils in thickness having sputter-deposited on one of its surfaces a three-layer composite heat-reflective sputter-deposited film made up of a 290Å
- -to-380Å
-thick layer consisting essentially of silver deposited between a 30Å
to 1000Å
thick transparent dielectric underlayer and a 500Å
-to-950Å
-thick top layer of transparent dielectric having an index of refraction of from 1.75 to 2.50 and an optical thickness of from 950Å
to 1800Å
. - View Dependent Claims (18, 19, 20, 21)
- -to-380Å
Specification