Transparent multilayer device
First Claim
1. A transparent multilayer device which reflects light in the infrared region of the spectrum and transmits light in the visible region of the spectrum, comprising:
- a birefringent polymer film comprising a plurality of layers wherein at least one of the layers comprises a first birefringent polymeric material and at least one of the layers comprises a second polymeric material, the first and second polymeric materials having a refractive index difference of less than 0.05 along a first axis orthogonal to a plane of the film, and having a refractive index difference of at least 0.05 along a second axis perpendicular to the first axis; and
a transparent conductor having at least one layer containing a metal or metal compound.
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Accused Products
Abstract
A transparent multilayer device which reflects light in the infrared region of the spectrum while transmitting light in the visible region of the spectrum. The device comprises a multilayered polymer film and a transparent conductor. The multilayered polymer film preferably comprises layers of a semi-crystalline naphthalene dicarboxylic acid polyester having an average thickness of not more than 0.5 microns and layers of a second polymer having an average thickness of not more than 0.5 microns. The layers of semi-crystalline naphthalene dicarboxylic acid polyester preferably have a positive stress optical coefficient. The transparent conductor comprises at least one layer containing a metal or a metal compound in which the metal compound is preferably selected from the group consisting of metal oxides, metal alloys, and combinations thereof. Silver and indium tin oxide are particularly preferred transparent conductors. The transparent multilayer devices may be applied to the surface of a glass or plastic substrate, such as an exterior window in a building, or to a windshield or window in an automobile, truck, or aircraft.
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Citations
15 Claims
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1. A transparent multilayer device which reflects light in the infrared region of the spectrum and transmits light in the visible region of the spectrum, comprising:
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a birefringent polymer film comprising a plurality of layers wherein at least one of the layers comprises a first birefringent polymeric material and at least one of the layers comprises a second polymeric material, the first and second polymeric materials having a refractive index difference of less than 0.05 along a first axis orthogonal to a plane of the film, and having a refractive index difference of at least 0.05 along a second axis perpendicular to the first axis; and
a transparent conductor having at least one layer containing a metal or metal compound. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A reflective article, comprising:
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a birefringent multilayer film including a first birefringent polymer layer and a second polymer layer contiguous to the first layer; and
a transparent conductor having at least one layer containing a metal or metal compound;
wherein the first and second polymer layers have refractive indices n1z, n2z respectively for light polarized along a first axis perpendicular to a plane of the multilayer film;
wherein the first and second polymer layers have refractive indices n1x, n2x respectively for light polarized along a second axis perpendicular to the first axis; and
wherein n1x is greater than n2x, and wherein n1z, is less than or equal to n2z.
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14. A reflective article, comprising:
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a birefringent multilayer film including a first birefringent polymer layer and a second polymer layer contiguous to the first layer; and
a transparent conductor having at least one layer containing a metal or metal compound;
wherein the first and second polymer layers have refractive indices n1z, n2z respectively for light polarized along a first axis perpendicular to a plane of the multilayer film;
wherein the first and second polymer layers have refractive indices n1x, n2x respectively for light polarized along a second axis perpendicular to the first axis; and
wherein n1x and n2x differ by an amount Δ
nx to provide a reflective interface between the first and second layer, wherein n1z and n2z differ by an amount Δ
nz, and wherein a ratio Δ
nz/Δ
nx is less than 0.5.
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15. A reflective article, comprising:
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a birefringent multilayer film including a first birefringent polymer layer and a second polymer layer contiguous to the first layer; and
a transparent conductor having at least one layer containing a metal or metal compound;
wherein the first and second polymer layers have refractive indices selected to provide a reflective interface therebetween whose reflectivity for p-polarized light has a property selected from the group of decreasing slowly with angle of incidence, being independent of angle of incidence, and increasing with angle of incidence.
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Specification