US4274035A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Field emission electron gun
Assignee: Hitachi Ltd
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Filing: 1979-07-11
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Granted: 1981-06-16
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Expires: 1999-07-11
Abstract
Abstract A field emission electron gun including a cathode, a control electrode which is disposed in the vicinity of the cathode, an anode which is disposed for accelerating electrons emitted from the cathode, and a source of a D.C. voltage to be applied between the cathode and the anode. Also, there is provided a switching arrangement capable of changing-over a potential of the control electrode between ground potential and a potential of the cathode, and an arrangement capable of varying relative positions of the cathode and the control electrode.
Inventors
- 👤 Satoru Fukuhara
- 👤 Hideo Todokoro
- 👤 Yoshio Sakitani
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 11:01
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/02; H01J37/04; H01J37/06; H01J37/073
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
118 words
A field emission electron gun comprising a cathode, a control electrode disposed in the vicinity of said cathode, and anode disposed along a beam path extending from said cathode for accelerating electrons emitted from said cathode, a variable D.C. voltage source connected between said cathode and said anode, switch means connected between said voltage source and said control electrode for changing-over the potential of said control electrode between ground potential and the potential of said cathode, and means for varying the position of said cathode relative to said control electrode said anode being fixed in position relative to one of said cathode and said control electrode at a position downstream of said control electrode along said beam path.
Claim 2
Dependent Claim
118 words
A field emission electron gun comprising a cathode, a control electrode disposed in the vicinity of said cathode, and anode disposed along a beam path extending from said cathode for accelerating electrons emitted from said cathode, a variable D.C. voltage source connected between said cathode and said anode, switch means connected between said voltage source and said control electrode for changing-over the potential of said control electrode between ground potential and the potential of said cathode, and means for varying the position of said cathode relative to said control electrode said anode being fixed in position relative to one of said cathode and said control electrode at a position downstream of said control electrode along said beam path.
Claim 3
Dependent Claim
33 words
A field emission electron gun according to claim 1, wherein said means for varying comprises means for moving said cathode whereby the relative positions of said cathode and said control electrode are variable.
Claim 4
Dependent Claim
34 words
A field emission electron gun according to claim 1, wherein said means for varying comprises means for moving said control electrode whereby the relative positions of said cathode and said control electrode are variable.
Claim 5
Dependent Claim
31 words
A field emission electron gun according to claim 1, wherein said control electrode has a cylindrical shape, and said cathode is arranged in a central part of the cylindrical control electrode.
Claim 6
Dependent Claim
24 words
A field emission electron gun according to claim 1, 2, 3, or 4, wherein the D.C. voltage source comprises a single variable high-voltage source.
Claim 7
Dependent Claim
42 words
A field emission electron gun according to claim 1, further comprising a vacuum vessel containing said cathode, said control electrode and said anode, said D.C. voltage source, said switching means and said means for varying being arranged exteriorly of said vacuum vessel.
Claim 8
Dependent Claim
39 words
A field emission electron gun according to claim 1, wherein said means for varying includes a vertical moving means for supporting at least one of said cathode and said control electrode for enabling varying of the relative positions thereof.
Claim 9
Dependent Claim
17 words
A field emission electron gun according to claim 7, wherein the vertical moving means includes a bellows.
Claim 10
Dependent Claim
145 words
A field emission electron gun comprising a cathode, a control electrode disposed in the vicinity of said cathode, an anode disposed along a beam path extending from said cathode for accelerating a beam of electrons emitted from said cathode, a D.C. voltage source connected between said cathode and said anode, and switch means connected between said voltage source and said control electrode for changing-over the potential of said control electrode between ground potential and the potential of said cathode, said voltage source being variable between a low energy voltage level while said control electrode is connected to ground potential and a high energy voltage level when said control electrode is connected to the same potential as said cathode such that the energy of said beam of electrons can be changed from a low level to a high level without significant increase in the beam current.
Claim 11
Dependent Claim
145 words
A field emission electron gun comprising a cathode, a control electrode disposed in the vicinity of said cathode, an anode disposed along a beam path extending from said cathode for accelerating a beam of electrons emitted from said cathode, a D.C. voltage source connected between said cathode and said anode, and switch means connected between said voltage source and said control electrode for changing-over the potential of said control electrode between ground potential and the potential of said cathode, said voltage source being variable between a low energy voltage level while said control electrode is connected to ground potential and a high energy voltage level when said control electrode is connected to the same potential as said cathode such that the energy of said beam of electrons can be changed from a low level to a high level without significant increase in the beam current.
References Cited (Backward Citations)
US3292041A
Cited
JPS524772A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-06-15 | 1984-12-15 | 1985-06-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-06-15 | 1988-12-15 | 1989-06-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-06-15 | 1992-12-15 | 1993-06-16 | $7700.00 | Window Closed / Lapsed |