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High refractive index materials for energy efficient lamps

A refractive index, higher technology for optical multilayer coatings that addresses intolerable degradation, coating failure, and inability to preserve optical and mechanical integrity

Inactive Publication Date: 2011-09-14
GENERAL ELECTRIC CO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Many known high-index materials fail to preserve their optical and mechanical integrity at lamp operating temperatures when used as components of optical interference coatings
Problems often manifest as loss of visible light transmission, degradation of reflection of IR radiation (where such reflection is desired), and / or coating failure in the form of excessive cracking or peeling
However, to achieve high energy efficiency, these varying degrees of degradation in optical and mechanical integrity cannot be tolerated

Method used

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  • High refractive index materials for energy efficient lamps
  • High refractive index materials for energy efficient lamps
  • High refractive index materials for energy efficient lamps

Examples

Experimental program
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Effect test

example 1

[0038] An exemplary multilayer material (36 layers) was deposited as a coating on a substrate. It has a total geometric thickness of about 4 microns and consists of alternating layers of high and low refractive index. The low index layer consists of silica, while the high index layer is sputter deposited NbTiAl oxide. The high refractive index material was deposited by sputtering a combination of metals Nb, Ti and Al in a mass ratio of 45:45:10 held in a sputtering target. Formulated, the deposited NbTiAl oxide material is estimated to be nominally composed of about 20.6 atomic % Al based on the total number of metal atoms, i.e., the NbTiAl oxide material satisfies the atomic ratio Al / (Nb+Ti+Al)= About 0.206. This material was then annealed at a temperature of 800° C. for 4 days, and its transmission spectrum was compared with that of the coating when deposition was complete. It has been found that the annealed coating has very little light scattering in the visible region....

example 2

[0040] In contrast, high refractive index materials composed of two component oxides do not similarly exhibit beneficial levels of low light scattering and high mechanical stability. For example, a multilayer material (120 layers) consisting of alternating high and low index layers is deposited onto a substrate as a coating, where the low index layer consists of silica and the high index layer contains sputter deposited NbTa oxide. The coating was only annealed at 800°C for 1 day. The light transmission of the annealed coating was compared to that of the coating when deposition was complete. The loss of transmission in the visible wavelength range for the annealed coating is evident and significantly worse compared to the three-component materials tested above, as image 3 shown. In the wavelength range of about 400-700 nm, the loss is in the range of 7-50% measured as spherical loss and 17-80% measured as specular loss. image 3 Shown are the scattering losses measured in...

example 3

[0042] Another embodiment of the invention relates to a three-component high index layer comprising TiAlTa oxide. A monolayer of this material was deposited by sputtering and then annealed at 800°C for a total of 4 days. The loss of its transmission after 4 days of annealing does not exceed about 1.5% in the visible and IR regions. see Figure 4 .

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Abstract

Disclosed herein are optical interference multilayer coatings comprising a plurality of alternating low refractive index and high refractive index layers, where the high refractive index layers comprise at least one mixed metal oxide selected from: NbTaX oxide where X is selected from the group consisting of Hf, Al and Zr; NbTiY oxide where Y is selected from the group consisting of Ta, Hf, Al and Zr; and TiAlZ oxide where Z is selected from the group consisting of Ta, Hf and Zr. Also disclosed herein are lamps comprising a light-transmissive envelope, at least a portion of the surface of the light-transmissive envelope being provided with the optical interference multilayer coating noted above. Such coatings, when used on lamps, may advantageously offer improved energy efficiencies for such lamps.

Description

technical field [0001] In general, the present invention relates to optical multilayer coatings having high refractive index layers. In particular, some embodiments herein relate to optical multilayer coatings having high refractive index layers comprising oxides of at least three metals. Background technique [0002] Optical interference coatings, sometimes called thin-film optical coatings or filters, consist of alternating layers of two or more materials of different refractive indices. Such coatings or films are known and have been used to selectively reflect or transmit optical radiation from various parts of the electromagnetic radiation spectrum, such as ultraviolet, visible and infrared radiation. For example, such optical interference coatings are used in the lamp industry to coat reflectors and lamp envelopes. One application in which optical interference coatings are useful is to increase the luminous efficiency or efficacy of a lamp by reflecting infrared energ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G02B5/28C23C14/08F21V9/08H01J61/40
CPCG02B5/282H01J61/35C23C14/08C23C14/083H01K1/325
Inventor 赵志博R·S·伊斯雷尔赵天吉B·A·古德
Owner GENERAL ELECTRIC CO