Patent US4312915A successfully refreshed from Google Patents.
US4312915A
Expired / Lapsed
US
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Cermet film selective black absorber
Assignee: Massachusetts Institute of Technology
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Filing: 1979-11-15
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Granted: 1982-01-26
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Expires: 1999-11-15
Abstract
Abstract A selective-black absorber capable of operation at elevated temperatures and high efficiency as a solar energy absorber is described. A cermet of MgO/Au, MgO/Pt, and Cr 2 O 3 /Cr having high solar energy absorptance and low infrared energy emissivity is coated on a substrate having high infrared reflectivity such as Mo coated on stainless steel; Ni coated on Cu, or steel; aluminum, or steel. Typically an absorption coefficient of about 0.93 with an emissivity of about 0.09 is obtained and operation at a temperature of 300°-400° C. is possible depending on the cermet and substrate materials.
Inventors
- 👤 John C. C. Fan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 02:35
CPC Classifications
F; F24; F24S; F24S70/00; F24S70/20; F24S70/25; F24S70/225; Y; Y02; Y02E; Y02E10/00; Y02E10/40; Y10; Y10S; Y10S126/00; Y10S126/907; Y10S126/908; Y10S428/00; Y10S428/913; Y10T; Y10T428/00; Y10T428/25; Y10T428/256; Y10T428/26; Y10T428/261
Claims Analysis
Total Claims: 26
Claim 1
Independent Claim
134 words
A selective black absorber capable of highly absorbing solar energy and only slightly emitting infrared energy comprising: a composite substrate comprising a plastic layer and a low infrared emissivity film coating deposited thereon and said composite substrate being electrically nonconductive in the direction normal to the layer of said composite substrate, a cermet film deposited on the film coating of said composite substrate, said cermet film comprising metal particles having diameters much less than the average wavelength of solar energy to be absorbed to cause the particles to behave as Lorentz oscillators in the visible light spectrum and thus be good solar energy absorbers, said cermet film having a thickness and composition such that it has high solar absorptance and low infrared thermal emissivity as a coating on said substrate having low infrared emissivity.
Claim 2
Dependent Claim
134 words
A selective black absorber capable of highly absorbing solar energy and only slightly emitting infrared energy comprising: a composite substrate comprising a plastic layer and a low infrared emissivity film coating deposited thereon and said composite substrate being electrically nonconductive in the direction normal to the layer of said composite substrate, a cermet film deposited on the film coating of said composite substrate, said cermet film comprising metal particles having diameters much less than the average wavelength of solar energy to be absorbed to cause the particles to behave as Lorentz oscillators in the visible light spectrum and thus be good solar energy absorbers, said cermet film having a thickness and composition such that it has high solar absorptance and low infrared thermal emissivity as a coating on said substrate having low infrared emissivity.
Claim 3
Dependent Claim
11 words
The absorber of claim 1 wherein said plastic layer is flexible.
Claim 4
Dependent Claim
13 words
The absorber of claim 1 wherein said substrate coating is a metal film.
Claim 5
Dependent Claim
11 words
The absorber of claim 3 wherein said cermet film is MgO/Au.
Claim 6
Dependent Claim
11 words
The absorber of claim 3 wherein said cermet film is MgO/Pt.
Claim 7
Dependent Claim
10 words
The absorber of claim 2 wherein said metal is Cu.
Claim 8
Dependent Claim
10 words
The absorber of claim 3 wherein said metal is aluminum.
Claim 9
Dependent Claim
29 words
The absorber of claim 3 where said composite substrate comprises in addition an infrared transparent electrical insulator on said metal coating on which insulator said cermet film is deposited.
Claim 10
Dependent Claim
11 words
The absorber of claim 8 wherein said insulator is an oxide.
Claim 11
Dependent Claim
14 words
The absorber of claim 8 wherein said oxide is the oxide of the cermet.
Claim 12
Dependent Claim
10 words
The absorber of claim 1 wherein said cermet is MgO/Au.
Claim 13
Dependent Claim
15 words
The absorber of claim 1 wherein said cermet film is Cr 2 O 3 /Cr.
Claim 14
Dependent Claim
12 words
The absorber of claim 12 wherein said substrate coating is a metal.
Claim 15
Dependent Claim
28 words
The absorber of claim 12 wherein said Cr 2 O 3 /Cr cermet film has a solar spectrum anti-reflection Cr 2 O 3 oxide film on its surface.
Claim 16
Dependent Claim
22 words
The absorber of claim 1 wherein said composite substrate is an infrared transparent insulator on a metallic film on a plastic base.
Claim 17
Dependent Claim
12 words
The absorber of claim 15 wherein said transparent insulator is an oxide.
Claim 18
Dependent Claim
14 words
The absorber of claim 16 wherein said oxide is the oxide of the cermet.
Claim 19
Dependent Claim
20 words
The absorber of claim 1 wherein said coating is a metallic film of sufficient thickness to provide low infrared emissivity.
Claim 20
Dependent Claim
17 words
The absorber of claim 1 wherein said metallic film is of the order of one μm thickness.
Claim 21
Dependent Claim
13 words
The absorber of claim 1 wherein said cermet is substantially 1500 A thick.
Claim 22
Dependent Claim
17 words
The absorber of claim 1 wherein said cermet metal particles are less than 200 A in diameter.
Claim 23
Dependent Claim
45 words
The absorber of claim 1 wherein said cermet is substantially 75 vol. %MgO, 25 vol. % Au, the thickness of said cermet is substantially 1600 A, and the diameters of said MgO and Au cermet particles of said MgO/Au cermet are less than 200 A.
Claim 24
Dependent Claim
129 words
A selective black absorber capable of highly absorbing solar energy and only slightly emitting infrared energy comprising: a metallic substrate having low infrared emissivity, an electrically insulating layer which is transparent to infrared radiation deposited on said metallic substrate to form a metallic substrate-insulating layer composite which is electrically insulating in the direction normal to the substrate, a cermet film deposited on the electrically insulating layer, said cermet film comprising metal particles having low emissivity in the infrared spectrum and diameters much less than the average wavelength of solar energy to be absorbed to cause the particles to behave as Lorenz oscillators and to be good solar energy absorbers, said cermet film having a thickness and composition such that it has high solar absorptance and low infrared thermal emissivity.
Claim 25
Dependent Claim
129 words
A selective black absorber capable of highly absorbing solar energy and only slightly emitting infrared energy comprising: a metallic substrate having low infrared emissivity, an electrically insulating layer which is transparent to infrared radiation deposited on said metallic substrate to form a metallic substrate-insulating layer composite which is electrically insulating in the direction normal to the substrate, a cermet film deposited on the electrically insulating layer, said cermet film comprising metal particles having low emissivity in the infrared spectrum and diameters much less than the average wavelength of solar energy to be absorbed to cause the particles to behave as Lorenz oscillators and to be good solar energy absorbers, said cermet film having a thickness and composition such that it has high solar absorptance and low infrared thermal emissivity.
Claim 26
Dependent Claim
33 words
The absorber of claim 23 wherein said electrically insulating layer is selected from the group consisting of MgO, Cr 2 O 3 , TiO 2 , MgF 2 , and BeF 2 .
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-01-25 | 1985-07-27 | 1986-01-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-01-25 | 1989-07-27 | 1990-01-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-01-25 | 1993-07-27 | 1994-01-26 | $7700.00 | Window Closed / Lapsed |