US4019077A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Field emission electron gun
Assignee: Hitachi Ltd
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Filing: 1975-12-19
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Granted: 1977-04-19
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Expires: 1995-12-19
Abstract
Abstract A field emission electron gun capable of generating a highly stabilized electron beam, comprises a cathode tip for emitting electrons, an anode for attracting and accelerating the electrons, and means for heating the anode. A surface layer of the anode, which is to be bombarded by the electrons, consists essentially of getter material such as Zr-Al alloy. The anode heating means serves for heating the surface layer, so as to remove the absorbed gas molecules and to elevate the gettering effect of the getter material, whereby the absorbed gas molecules in the anode are hardly released therefrom, even if the anode surface is bombarded by the electrons. Therefore, the number of ions impinging on the cathode tip is remarkably reduced, and a stable electron beam can be obtained from the cathode tip.
Inventors
- 👤 Yoshio Sakitani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 21:45
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/02; H01J37/04; H01J37/06; H01J37/073; H01J1/00; H01J1/02; H01J1/30; H01J1/304; H01J7/00; H01J7/14; H01J7/18
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
75 words
In a field emission electron gun including: a cathode for emitting electrons, an anode for attracting said electrons and toward which said electrons are accelerated, and a high D.C. voltage source connected between said cathode and said anode, the improvement wherein at least a portion of a surface of said anode upon which said electrons impinge is made of getter material, and said gun further includes means for heating said anode at a high temperature.
Claim 2
Dependent Claim
75 words
In a field emission electron gun including: a cathode for emitting electrons, an anode for attracting said electrons and toward which said electrons are accelerated, and a high D.C. voltage source connected between said cathode and said anode, the improvement wherein at least a portion of a surface of said anode upon which said electrons impinge is made of getter material, and said gun further includes means for heating said anode at a high temperature.
Claim 3
Dependent Claim
26 words
The improvement according to claim 1, wherein said getter material includes at least one component selected from the group consisting of titanium, zirconium, thorium and barium.
Claim 4
Dependent Claim
13 words
The improvement according to claim 1, wherein said getter material is zirconium-aluminum alloy.
Claim 5
Dependent Claim
18 words
The improvement according to claim 1, wherein the entirety of said anode is made of said getter material.
Claim 6
Dependent Claim
24 words
The improvement according to claim 1, wherein only a prescribed portion of said anode upon which said electrons impinge is made of getter material.
Claim 7
Dependent Claim
20 words
The improvement according to claim 5, wherein said prescribed portion of said anode comprises a surface layer of getter material.
Claim 8
Dependent Claim
21 words
The improvement according to claim 6, wherein said surface layer is a layer of getter material coated on an anode base.
Claim 9
Dependent Claim
20 words
The improvement according to claim 6, wherein said surface layer is a lining of getter material formed on said anode.
Claim 10
Dependent Claim
24 words
The improvement according to claim 7, wherein said surface layer is a coating of getter material which has been evaporated on said anode base.
Claim 11
Dependent Claim
35 words
The improvement according to claim 1, wherein said means for heating said anode comprises a heating coil disposed adjacent but spaced apart from said anode and a heating power source connected to said heating coil.
Claim 12
Dependent Claim
22 words
The improvement according to claim 1, wherein said means for heating said anode comprises a heating power source connected to said anode.
Claim 13
Dependent Claim
32 words
The improvement according to claim 1, wherein said means for heating said anode comprises a thermal electron emitting filament and a high voltage D.C. source connected between said filament and said anode.
Claim 14
Dependent Claim
25 words
The improvement according to claim 10, wherein said anode is cup-shaped and said heating coil is disposed adjacent the interior wall of said cup-shaped anode.
References Cited (Backward Citations)
US3374386A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-04-18 | 1980-10-18 | 1981-04-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-04-18 | 1984-10-18 | 1985-04-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-04-18 | 1988-10-18 | 1989-04-19 | $7700.00 | Window Closed / Lapsed |