US4291252A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electron tube cathode
Assignee: Hitachi Ltd
•
Filing: 1979-11-20
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Granted: 1981-09-22
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Expires: 1999-11-20
Abstract
Abstract An electron tube cathode has a composite suppression layer structure interposed between the base metal and the electron-emitting material to suppress an interface layer formed through the reaction of the base metal with the electron emissive material. The composite layer structure includes a thin layer of Pt or Re and a layer of oxide of Zr and/or Hf. As a result, the formation of the interface layer is prevented so that the useful life of the electron tube cathode is prolonged.
Inventors
- 👤 Toshiyuki Aida
- 👤 Shigehiko Yamamoto
- 👤 Sadanori Taguchi
- 👤 Isamu Yuito
- 👤 Yukio Honda
- 👤 Ushio Kawabe
- 👤 Akira Misumi
- 👤 Takao Kawamura
- 👤 Hiroshi Fukushima
- 👤 Yoshio Degawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 19:59
CPC Classifications
H; H01; H01J; H01J1/00; H01J1/02; H01J1/13; H01J1/14
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
94 words
An electron tube cathode comprising a base metal of Ni alloy containing W solved therein up to its solubility limit and a reducing impurity of small amount, a layer of an oxide of metal provided on said base metal including at least one material selected from a group consisting of Zr and Hf, a thin film of metal provided on said metal oxide layer including one selected from a group consisting of Pt and Re, and a coating of electron emissive material provided on said thin metal film including an alkaline earth metal oxide.
Claim 2
Dependent Claim
94 words
An electron tube cathode comprising a base metal of Ni alloy containing W solved therein up to its solubility limit and a reducing impurity of small amount, a layer of an oxide of metal provided on said base metal including at least one material selected from a group consisting of Zr and Hf, a thin film of metal provided on said metal oxide layer including one selected from a group consisting of Pt and Re, and a coating of electron emissive material provided on said thin metal film including an alkaline earth metal oxide.
Claim 3
Dependent Claim
25 words
An electron tube cathode as claimed in claim 1, wherein the amount of W solved in said Ni alloy is 20 to 28% by weight.
Claim 4
Dependent Claim
22 words
An electron tube cathode as claimed in claim 1, wherein the thickness of said metal oxide layer is 100 to 10000 A.
Claim 5
Dependent Claim
22 words
An electron tube cathode as claimed in claim 1, wherein the thickness of said thin metal film is 1000 to 2000 A.
Claim 6
Dependent Claim
23 words
An electron tube cathode as claimed in claim 1, wherein said metal oxide layer is made of ZrO 2 or HfO 2 .
Claim 7
Dependent Claim
18 words
An electron tube cathode as claimed in claim 1, wherein said thin metal film is made of Pt.
Claim 8
Dependent Claim
27 words
An electron tube cathode as claimed in claim 1, wherein said reducing impurity is at least one metal selected from a group consisting of Zr and Hf.
Claim 9
Dependent Claim
39 words
An electron tube cathode as claimed in claim 1, wherein a layer of fine powders of one selected from a group consisting of Ni and Ni-W alloy is provided between said metal oxide layer and said thin metal film.
References Cited (Backward Citations)
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US3580739A
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US3553521A
Cited
US3691421A
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US3745403A
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US4019081A
Cited
US4137476A
Cited
US4208208A
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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) | 1984-09-21 | 1985-03-23 | 1985-09-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-09-21 | 1989-03-23 | 1989-09-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-09-21 | 1993-03-23 | 1993-09-22 | $7700.00 | Window Closed / Lapsed |