US3840955A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for producing a field effect control device
Assignee: Individual
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Filing: 1973-12-12
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Granted: 1974-10-15
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Expires: 1993-12-12
Abstract
Abstract A field effect control device useful as an electronic switch or an amplifier, has as the basic element a field effect emitter comprising a large array of emitting fibers encompassed with an insulating oxide support structure and a control electrode formed across the surface of the oxide. Novel construction of the device is by etching a surface of the field effect emitter to expose the fiber ends. The control electrode is deposited across this surface, covering both the insulator and the protruding emitter pins. The fiber ends are polished to exposure and etched to a predetermined level below the insulator surface. the control electrode, not affected by the etching solution, remains on the surface of the control device with holes therethrough left by the etched-back fibers, the holes being precisely aligned with the fibers. A conductive backing plate connected to the fibers allows a voltage to be coupled thereto and a collector electrode disposed opposite the control electrode allows the field to be developed for operation of the control device.
Inventors
- 👤 J Shelton
- 👤 R Norman
- 👤 J Hagood
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 18:24
CPC Classifications
H; H01; H01J; H01J1/00; H01J1/02; H01J1/30; H01J1/304
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
201 words
A process for producing an electrical field effect control device comprising the steps of: providing a field effect emitter material having a plurality of parallel metal fibers per unit area encompassed by an insulating material, exposing respective first and second ends of said parallel fibers along respective first aNd second surfaces of said insulating material, etching said insulating material across said first surface with a first etching agent to reduce the thickness of said insulator and thereby further expose said fibers, depositing an etch-resistant layer of conductive material over the etched surface of said emitter material, polishing said conductive material with an abrasive to re-expose said metal fibers without exposing said insulator material, etching said exposed metal fibers across the surface of said emitter material with a second etching agent for reducing the length of said fibers to a plane or level below the surface level of said insulator, joining a conductive backing plate to said second ends of said parallel fibers for conducting an electrical potential thereto, and providing a collector electrode spatially disposed across from said etch-resistant, conductive material in a plane parallel with said first surface of said emitter material, and thereby providing said field effect control device.
Claim 2
Dependent Claim
201 words
A process for producing an electrical field effect control device comprising the steps of: providing a field effect emitter material having a plurality of parallel metal fibers per unit area encompassed by an insulating material, exposing respective first and second ends of said parallel fibers along respective first aNd second surfaces of said insulating material, etching said insulating material across said first surface with a first etching agent to reduce the thickness of said insulator and thereby further expose said fibers, depositing an etch-resistant layer of conductive material over the etched surface of said emitter material, polishing said conductive material with an abrasive to re-expose said metal fibers without exposing said insulator material, etching said exposed metal fibers across the surface of said emitter material with a second etching agent for reducing the length of said fibers to a plane or level below the surface level of said insulator, joining a conductive backing plate to said second ends of said parallel fibers for conducting an electrical potential thereto, and providing a collector electrode spatially disposed across from said etch-resistant, conductive material in a plane parallel with said first surface of said emitter material, and thereby providing said field effect control device.
Claim 3
Dependent Claim
16 words
The process as set forth in claim 1 wherein said coating of conductive material is gold.
Claim 4
Dependent Claim
21 words
The process as set forth in claim 2 wherein said insulating material is uranium oxide and said metal fibers are tungsten.
Claim 5
Dependent Claim
48 words
The process as set forth in claim 3 wherein etching of said insulator surface is done with a preferential etch of 20 milliliters of glacial acetic acid, 40 milliliters of saturated aqueous solution of CrO3, 6 milliliters of concentrated nitric acid, and 4 milliliters of concentrated hydrofluoric acid.
Claim 6
Dependent Claim
30 words
The process as set forth in claim 4 wherein etching of said exposed fibers is with a preferential etch of 2 milligrams of NH4 NO3 in 100 milliliters concentrated H2SO4.
Claim 7
Dependent Claim
149 words
A process for producing an electrical field effect control device comprising the steps of: providing a field effect emitter material having a plurality of parallel, metal fibers per unit area encompassed by an insulating material, exposing respective first and second ends of said parallel fibers along respective first and second surfaces of said insulating material, etching said exposed metal fibers across said first surface with a first etching agent to reduce the length of said fibers to plane below the surface level of said insulator, depositing a layer of conductive material over the etched surface of said emitter material, joining a conductive backing plate to said second ends of said parallel fibers for conducting an electrical potential thereto, and providing a collector electrode spatially disposed across from said conductive layer in a parallel plane with said first surface of said emitter material, thereby providing said field effect control device.
Claim 8
Dependent Claim
149 words
A process for producing an electrical field effect control device comprising the steps of: providing a field effect emitter material having a plurality of parallel, metal fibers per unit area encompassed by an insulating material, exposing respective first and second ends of said parallel fibers along respective first and second surfaces of said insulating material, etching said exposed metal fibers across said first surface with a first etching agent to reduce the length of said fibers to plane below the surface level of said insulator, depositing a layer of conductive material over the etched surface of said emitter material, joining a conductive backing plate to said second ends of said parallel fibers for conducting an electrical potential thereto, and providing a collector electrode spatially disposed across from said conductive layer in a parallel plane with said first surface of said emitter material, thereby providing said field effect control device.
Claim 9
Dependent Claim
21 words
The process as set forth in claim 6 wherein said insulating material is zirconium oxide and said metal fibers are tungsten.
Claim 10
Dependent Claim
30 words
The process as set forth in claim 7 wherein etching of said exposed fibers is with a preferential etch of 2 milligrams of NH4 NO3 in 100 milliliters concentrated H2SO4.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-10-14 | 1978-04-15 | 1978-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-10-14 | 1982-04-15 | 1982-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-10-14 | 1986-04-15 | 1986-10-15 | $7700.00 | Window Closed / Lapsed |