US3711908A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for forming small diameter tips on sintered material cathodes
Assignee: International Business Machines Corp
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Filing: 1970-08-27
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Granted: 1973-01-23
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Expires: 1990-08-27
Abstract
Abstract There is disclosed a method for forming tips on normally sintered material electron-emitting cathodes. The method comprises melting the electron-emitting end of the cathode with an electron beam or other suitable narrow beam heating means, such as a laser, for example. This melting produces a dense fused mass at the end of the cathode. This fused mass can then be polished to a tip having a very small diameter such as substantially less than 5 microns.
Inventors
- 👤 A Broers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 19:42
CPC Classifications
H; H01; H01J; H01J9/00; H01J9/02; H01J9/022; H01J9/025; B; B23; B23K; B23K15/00; B23K15/0046; B23K15/0093; B23K26/00; B23K26/0006; B23K26/352; B23K26/354; B23K2101/00; B23K2101/32; B23K2103/00; B23K2103/50
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
59 words
The method of forming a tip on a lanthanum hexaboride cathode comprising melting an end of said lanthanum hexaboride cathode from which electron emission is to be drawn by treating said end with an electron energy beam, allowing the melted portion of said cathode to resolidify and thereafter polishing said resolidified end of said cathode to the desired diameter.
Claim 2
Dependent Claim
37 words
The method of forming a tip on a lanthanum hexaboride cathode as defined in claim 2, wherein said electron energy beam is directed axially toward the end of said lanthanum hexaboride cathode in order to melt it.
Claim 3
Dependent Claim
25 words
the method of forming a tip on a lanthanum hexaboride cathode as defined in claim 2, wherein said lanthanum hexaboride cathode comprises sintered lanthanum hexaboride.
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) | 1976-01-23 | 1976-07-24 | 1977-01-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-23 | 1980-07-24 | 1981-01-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-23 | 1984-07-24 | 1985-01-23 | $7700.00 | Window Closed / Lapsed |