US4917940A
Expired / Lapsed
US
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Method of forming a multiple layer dielectric and a hot film sensor therewith
Assignee: National Aeronautics and Space Administration
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Filing: 1988-04-01
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Granted: 1990-04-17
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Expires: 2008-04-01
Abstract
Abstract A multiple layer dielectric for use in a hot-film laminar separation layer 21. The multiple layer dielectric substrate is formed by depositing a first layer 22 of a thermoplastic polymer such as on an electrically conductive substrate such as the metal surface 23 of a model 24 to be tested under cryogenic conditions and high Reynolds numbers. Next, a second dielectric layer 26 of fused silica is formed on the first dielectric layer 22 of thermoplastic polymer. A resistive metal film is deposited on selected areas of the multiple layer dielectric substrate of form one or more hot-film sensor elements 27 to which aluminum electrical circuits 28 deposited upon the multiple layered dielectric substrate are connected.
Inventors
- 👤 Jr. Purnell Hopson
- 👤 Sang Q. Tran
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 05:50
CPC Classifications
G; G01; G01P; G01P5/00; G01P5/10; G01P5/12; G01F; G01F1/00; G01F1/68; G01F1/684; G01F1/6845; Y; Y10; Y10S; Y10S428/00; Y10S428/901; Y10T; Y10T428/00; Y10T428/24; Y10T428/24942; Y10T428/2495; Y10T428/24967; Y10T428/24975; Y10T428/31504; Y10T428/31678
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
86 words
A hot-film sensor for use on an electrically conductive surface comprising: a first layer of a thermoplastic polymer formed on an electrically conductive surface; a second layer of fused silica formed on said first layer of thermoplastic polymer to form a multiple layer dielectric substrate; an electrically resistive film of metal formed on selected areas of said dielectric substrate to form one or more multiple layer hot-film sensor elements and electrical circuits formed on said multiple layer dielectric substrate connecting one or more hot-film sensing elements.
Claim 2
Dependent Claim
86 words
A hot-film sensor for use on an electrically conductive surface comprising: a first layer of a thermoplastic polymer formed on an electrically conductive surface; a second layer of fused silica formed on said first layer of thermoplastic polymer to form a multiple layer dielectric substrate; an electrically resistive film of metal formed on selected areas of said dielectric substrate to form one or more multiple layer hot-film sensor elements and electrical circuits formed on said multiple layer dielectric substrate connecting one or more hot-film sensing elements.
Claim 3
Dependent Claim
75 words
The invention as defined in claim 1 wherein said first layer of thermoplastic polymer is formed of a coating of poly-monochloro-para-xylyene up to 5.0 microns in thickness; said second layer of fused silica is up to 1.0 microns in thickness; said one or more hot-film sensor elements are formed of an electrically resistive nickel-chrome film up to 2200 Å in thickness; and said electrical circuits are formed of aluminum up to 5000 Å in thickness.
Claim 4
Dependent Claim
44 words
A multiple layer dielectric formed on a metal substrate comprising: a first layer of a thermoplastic polymer including a base member of poly-para-xlylene; and a second layer of fused silica (S i O 2 ) formed on said first layer of said thermoplastic polymer.
Claim 5
Dependent Claim
44 words
A multiple layer dielectric formed on a metal substrate comprising: a first layer of a thermoplastic polymer including a base member of poly-para-xlylene; and a second layer of fused silica (S i O 2 ) formed on said first layer of said thermoplastic polymer.
Claim 6
Dependent Claim
35 words
The invention as defined in claim 3 wherein said first layer of thermoplastic polymer is up to 5 microns in thickness and said second layer of fused silica is up to 1.0 microns in thickness.
References Cited (Backward Citations)
US4061029A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-04-16 | 1993-10-16 | 1994-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-04-16 | 1997-10-16 | 1998-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-04-16 | 2001-10-16 | 2002-04-17 | $7700.00 | Window Closed / Lapsed |