Incandescent lamp incorporating extended high-reflectivity IR coating and lighting fixture incorporating such an incandescent lamp
First Claim
1. An incandescent lamp comprising:
- a filament;
a transparent envelope defining an enclosed space in which the filament is located; and
an optical coating disposed on a surface of the envelope, for transmitting light emitted by the filament in a prescribed visible wavelength band, while reflecting back toward the filament light emitted by the filament in other wavelength bands, whereupon a portion of such reflected light is absorbed by the filament;
wherein the optical coating includes a plurality of dielectric layers having prescribed refractive indices and prescribed thicknesses, which are selected such that the optical coating provides a prescribed transmittance/reflectance spectrum having an average reflectance greater than 90% across an infrared wavelength range of 740 to 2000 nm and further having an average transmittance of less than 90% across a visible wavelength range of 400 to 700 nm;
and wherein the optical coating cooperates with the filament such that the lamp provides a higher luminous efficacy than would a corresponding lamp lacking such an optical coating.
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Accused Products
Abstract
An incandescent lamp is disclosed, incorporating a special optical coating system that enables the lamp to provide an improved luminous efficacy. In one form, the optical coating system includes a plurality of dielectric layers having prescribed refractive indices and prescribed thicknesses, which are selected such that the optical coating provides a prescribed transmittance/reflectance spectrum having an average reflectance greater than 90% across an infrared wavelength range of 740 to 2000 nm and further having an average transmittance of less than 90% across a visible wavelength range of 400 to 700 nm. In another form, the optical coating system includes two distinct coatings: (1) a first coating including a plurality of dielectric layers having prescribed refractive indices and prescribed thicknesses, which are selected such that the first coating provides a prescribed transmittance/reflectance spectrum, and (2) a second coating including a transparent electrically conductive material configured such that the second coating provides a prescribed transmittance/reflectance spectrum. The invention also is embodied in a lighting fixture incorporating an optical coating as described above, located either on the envelope of the incandescent lamp, itself, or on another substrate of the fixture, separate and apart from the lamp, e.g., a fixed transparent envelope surrounding the incandescent lamp.
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Citations
47 Claims
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1. An incandescent lamp comprising:
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a filament;
a transparent envelope defining an enclosed space in which the filament is located; and
an optical coating disposed on a surface of the envelope, for transmitting light emitted by the filament in a prescribed visible wavelength band, while reflecting back toward the filament light emitted by the filament in other wavelength bands, whereupon a portion of such reflected light is absorbed by the filament;
wherein the optical coating includes a plurality of dielectric layers having prescribed refractive indices and prescribed thicknesses, which are selected such that the optical coating provides a prescribed transmittance/reflectance spectrum having an average reflectance greater than 90% across an infrared wavelength range of 740 to 2000 nm and further having an average transmittance of less than 90% across a visible wavelength range of 400 to 700 nm;
and wherein the optical coating cooperates with the filament such that the lamp provides a higher luminous efficacy than would a corresponding lamp lacking such an optical coating. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 40, 41, 42, 43)
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12. A lighting fixture comprising:
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a housing;
a lamp socket carried by the housing; and
an incandescent lamp comprising an electrical connector configured to be removably secured to the lamp socket, a filament, a transparent envelope secured to the electrical connector and defining an enclosed space in which the filament is located, and an optical coating disposed on a surface of the envelope, for transmitting light emitted by the lamp filament in a prescribed visible wavelength band, while reflecting back toward the filament light emitted by the filament in other wavelength bands, whereupon a portion of such reflected light is absorbed by the filament;
wherein the optical coating includes a plurality of dielectric layers having prescribed refractive indices and prescribed thicknesses, which are selected such that the optical coating provides a prescribed transmission/reflection spectrum having an average reflectance greater than 90% across an infrared wavelength range of 740 to 2000 nm and further having an average transmittance of less than 90% across a visible wavelength range of 400 to 700 nm;
and wherein the optical coating cooperates with the filament such that the lighting fixture provides a higher luminous efficacy than would a corresponding lighting fixture lacking such an optical coating.
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13. A lighting fixture comprising:
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a housing;
a lamp socket carried by the housing; and
an incandescent lamp comprising an electrical connector configured to be removably secured to the lamp socket, a filament, and a transparent envelope secured to the electrical connector and defining an enclosed space in which the filament is located;
wherein the lighting fixture further comprises an optical coating for transmitting light emitted by the lamp filament in a prescribed visible wavelength band, while reflecting back toward the filament light emitted by the filament in other wavelength bands, whereupon a portion of such reflected light is absorbed by the filament;
wherein the optical coating includes a plurality of dielectric layers having prescribed refractive indices and prescribed thicknesses, which are selected such that the optical coating provides a prescribed transmittance/reflectance spectrum having an average reflectance greater than 90% across an infrared wavelength range of 740 to 2000 nm and further having an average transmittance of less than 90% across a visible wavelength range of 400 to 700 nm;
and wherein the optical coating cooperates with the filament such that the lighting fixture provides a higher luminous efficacy than would a corresponding lighting fixture lacking such an optical coating. - View Dependent Claims (14, 15, 16)
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17. An incandescent lamp comprising:
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a filament;
a transparent envelope defining an enclosed space in which the filament is located; and
an optical coating system disposed on a surface of the envelope, for transmitting light emitted by the filament in a prescribed visible wavelength band, while reflecting back toward the filament light emitted by the filament in other wavelength bands, whereupon a portion of such reflected light is absorbed by the filament;
wherein the optical coating system includes a first coating including a plurality of dielectric layers having prescribed refractive indices and prescribed thicknesses, which are selected such that the first coating provides a prescribed transmittance/reflectance spectrum, and a second coating including a transparent electrically conductive material having a thickness selected such that the second coating provides a prescribed transmittance/reflectance spectrum, wherein the first and second coatings cooperate with each other and with the filament such that the lamp provides a higher luminous efficacy than would a corresponding lamp lacking such an optical coating system on its envelope. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 44, 45, 46, 47)
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35. A lighting fixture comprising:
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a housing;
a lamp socket carried by the housing; and
an incandescent lamp comprising an electrical connector configured to be removably secured to the lamp socket, a filament, a transparent envelope secured to the electrical connector and defining an enclosed space in which the filament is located, and an optical coating system disposed on a surface of the envelope, for transmitting light emitted by the lamp filament in a prescribed visible wavelength band, while reflecting back toward the filament light emitted by the filament in other wavelength bands, whereupon a portion of such reflected light is absorbed by the filament, wherein the optical coating system includes a first coating including a plurality of dielectric layers having prescribed refractive indices and prescribed thicknesses, which are selected such that the first coating provides a prescribed transmittance/reflectance spectrum, and a second coating including a transparent electrically conductive material having a thickness selected such that the second coating provides a prescribed transmittance/reflectance spectrum, wherein the first and second coatings cooperate with each other and with the filament such that the lamp provides a higher luminous efficacy than would a corresponding lamp lacking such an optical coating system on its envelope.
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36. A lighting fixture comprising:
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a housing;
a lamp socket carried by the housing; and
an incandescent lamp comprising an electrical connector configured to be removably secured to the lamp socket, a filament, and a transparent envelope secured to the electrical connector and defining an enclosed space in which the filament is located, wherein the fixture further comprises an optical coating system for transmitting light emitted by the filament in a prescribed visible wavelength band, while reflecting back toward the filament light emitted by the filament in other wavelength bands, whereupon a portion of such reflected light is absorbed by the filament;
and wherein the optical coating system includes a first coating including a plurality of dielectric layers having prescribed refractive indices and prescribed thicknesses, which are selected such that the first coating provides a prescribed first transmission/reflection spectrum, and a second coating including a transparent electrically conductive material having a thickness selected such that the second coating provides a prescribed second transmission/reflection spectrum, wherein the first and second coatings cooperate with each other and with the filament such that the lighting fixture provides a higher luminous efficacy than would a corresponding lighting fixture lacking such an optical coating system. - View Dependent Claims (37, 38, 39)
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Specification