US4007393A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Barium-aluminum-scandate dispenser cathode
Assignee: US Philips Corp
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Filing: 1975-12-02
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Granted: 1977-02-08
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Expires: 1995-12-02
Abstract
Abstract A dispenser cathode comprising a porous metal body which has an emissive surface and the pores of which contain one or more compounds for dispensing at least barium and scandium to the emissive surface, which compounds are composed of at least barium oxide, scandium oxide and aluminium oxide, in which the quantity of scandium oxide is less than 10% by weight, and preferably 3% by weight, of the overall quantity of the dispensing compound (s), has substantially the same good emissive properties as cathodes in which the dispensing compound comprises 5.5% by weight of scandium oxide and 18% by weight of yttrium oxide (Y 2 O 3 ), or barium scandate as a dispensing compound.
Inventors
- 👤 Antonius Johannes Alberta VAN Stratum
- 👤 Johannes Gerardus VAN Os
- 👤 Johannes Reinier Blatter
- 👤 Pieter Zalm
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 10:24
CPC Classifications
H; H01; H01J; H01J1/00; H01J1/02; H01J1/13; H01J1/20; H01J1/28; H01J1/14
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
71 words
A dispenser cathode comprising a porous metal body which has an emissive surface and the pores of which contain compounds for dispensing when heated at least barium and scandium to the emissive surface, said compounds comprising at least barium oxide, scandium oxide and aluminum oxide wherein the total quantity of rare earth oxides present including scandium oxide being less than 10% by weight of the overall quantity of the dispensing compounds.
Claim 2
Dependent Claim
71 words
A dispenser cathode comprising a porous metal body which has an emissive surface and the pores of which contain compounds for dispensing when heated at least barium and scandium to the emissive surface, said compounds comprising at least barium oxide, scandium oxide and aluminum oxide wherein the total quantity of rare earth oxides present including scandium oxide being less than 10% by weight of the overall quantity of the dispensing compounds.
Claim 3
Dependent Claim
31 words
A dispenser cathode as claimed in claim 1, wherein the quantity of scandium oxide present is from 2% to 7% by weight of the the overall quantity of the dispensing compounds.
Claim 4
Dependent Claim
28 words
A dispenser cathode as claimed in claim 2, wherein the quantity of scandium oxide present is approximately 3% by weight of the overall quantity of the dispensing compounds.
Claim 5
Dependent Claim
43 words
A dispenser cathode as claimed in claim 1, wherein the dispensing compounds also comprise calcium oxide, the ratio between the barium oxide, calcium oxide and aluminum oxide being in the range of 5 : 3 : 2 to 4 : 1 : 1.
Claim 6
Dependent Claim
22 words
A dispenser cathode as claimed in claim 1, wherein the metal body comprises tungsten, and the dispensing compounds are a fused mixture.
Claim 7
Dependent Claim
22 words
A dispenser cathode as claimed in claim 5, wherein the dispensing compounds are provided in the pores by impregnation from a melt.
Claim 8
Dependent Claim
17 words
A dispenser cathode as claimed in claim 1, wherein the dispensing compounds are free of yttrium oxide.
Claim 9
Dependent Claim
13 words
An electric discharge tube having a dispenser cathode as claimed in claim 1.
References Cited (Backward Citations)
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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) | 1980-02-08 | 1980-08-09 | 1981-02-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-02-08 | 1984-08-09 | 1985-02-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-02-08 | 1988-08-09 | 1989-02-08 | $7700.00 | Window Closed / Lapsed |