US4101800A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Controlled-porosity dispenser cathode
Assignee: United States Department of the Navy
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Filing: 1977-07-06
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Granted: 1978-07-18
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Expires: 1997-07-06
Abstract
Abstract An emissive member for a controlled-porosity, dispenser-type cathode comping a three-component sandwich consisting of: (1) a supporting disc; (2) a layer of nonsintered alkaline earth material on said disc; and (3) a thin perforated foil on said layer. The foil is made of refractory metal and has a uniform pattern of tiny holes through which the active material of the reservoir migrates to coat the surface of the foil, the foil thus serving as the electron-emitting surface of the cathode.
Inventors
- 👤 Richard E. Thomas
- 👤 Titus Pankey, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 17:52
CPC Classifications
H; H01; H01J; H01J1/00; H01J1/02; H01J1/13; H01J1/20; H01J1/28
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
97 words
A thermionic, dispenser-type cathode having an emissive member comprising: a backing plug; a "nonporous" reservoir of active cathode material, comprising a quantity of at least one alkaline earth material, adjacent said backing plug; and a foil disposed on the free surface of said reservoir, said foil being formed from at least one refractory metal with a set of uniformly sized and spaced holes therein to permit the active electron-emitting material within said reservoir to migrate through said holes and to spread over the surface of said foil when the reservoir material is heated to the proper temperature.
Claim 2
Dependent Claim
97 words
A thermionic, dispenser-type cathode having an emissive member comprising: a backing plug; a "nonporous" reservoir of active cathode material, comprising a quantity of at least one alkaline earth material, adjacent said backing plug; and a foil disposed on the free surface of said reservoir, said foil being formed from at least one refractory metal with a set of uniformly sized and spaced holes therein to permit the active electron-emitting material within said reservoir to migrate through said holes and to spread over the surface of said foil when the reservoir material is heated to the proper temperature.
Claim 3
Dependent Claim
13 words
A cathode as in claim 1, wherein said foil is formed from iridium.
Claim 4
Dependent Claim
16 words
A cathode as in claim 1, wherein said foil is formed from an iridium-coated refractory metal.
Claim 5
Dependent Claim
36 words
A cathode as in claim 1, wherein said reservoir contains a mixture of at least one alkaline earth material and at least one metal powder taken from the group of elements consisting of tantalum and zirconium.
Claim 6
Dependent Claim
36 words
A cathode as in claim 1, wherein said reservoir contains a mixture of at least one alkaline earth material and at least one metal powder which is a chemical reducing agent for the alkaline earth material.
Claim 7
Dependent Claim
22 words
A cathode as in claim 5, wherein said metal powder is no more than about 30 percent by volume of the mixture.
Claim 8
Dependent Claim
18 words
A cathode as in claim 1, wherein said holes in said foil are approximately 25 microns in diameter.
Claim 9
Dependent Claim
17 words
A cathode as in claim 7, wherein the centers of said holes are approximately 50 microns apart.
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) | 1981-07-17 | 1982-01-16 | 1982-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-07-17 | 1986-01-16 | 1986-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-07-17 | 1990-01-16 | 1990-07-18 | $7700.00 | Window Closed / Lapsed |