US3825839A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Constant current field emission electron gun
Assignee: Jeol Ltd
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Filing: 1972-04-19
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Granted: 1974-07-23
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Expires: 1992-04-19
Abstract
Abstract An improved field emission type electron gun is automatically controlled so as to generate a stable emission current. The preferred embodiment employs a detecting means for detecting the emission current fluctuation and a control means for controlling the electric field for field emission according to the output signal of said detecting means.
Inventors
- 👤 T Goto
- 👤 T Someya
- 👤 N Kobayshi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:45
CPC Classifications
H; H01; H01J; H01J37/00; H01J37/02; H01J37/04; H01J37/06; H01J37/073; F; F21; F21V; F21V17/00; F21V17/06; H01J37/24; H01J37/243; H02; H02H; H02H7/00; H02H7/20
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
182 words
A field emission type electron gun comprising: an emitter for emitting an electron beam, a heating means for heating said emitter, a first anode for generating a strong electric field at said emitter, a first voltage source for generating a potential difference between said first anode and said emitter, a second anode located behind the first anode maintained at ground potential, a second high voltage source for supplying negative high potential to said emitter for accelerating said electron beam, a first detecting means for detecting the electron beam emitted from said emitter and providing a signal indicative of electron beam fluctuation, a comparing means for comparing the output signal of said first detecting means with a reference signal and providing an output signal indicative of the comparison, a control means for controlling the output voltage of said first voltage source in response to the output signal of said comparing means, and a second detecting means for detecting the change in output voltage of said first voltage source providing an output signal indicative of the progress of crystal buildup on the emitter surface.
Claim 2
Dependent Claim
182 words
A field emission type electron gun comprising: an emitter for emitting an electron beam, a heating means for heating said emitter, a first anode for generating a strong electric field at said emitter, a first voltage source for generating a potential difference between said first anode and said emitter, a second anode located behind the first anode maintained at ground potential, a second high voltage source for supplying negative high potential to said emitter for accelerating said electron beam, a first detecting means for detecting the electron beam emitted from said emitter and providing a signal indicative of electron beam fluctuation, a comparing means for comparing the output signal of said first detecting means with a reference signal and providing an output signal indicative of the comparison, a control means for controlling the output voltage of said first voltage source in response to the output signal of said comparing means, and a second detecting means for detecting the change in output voltage of said first voltage source providing an output signal indicative of the progress of crystal buildup on the emitter surface.
Claim 3
Dependent Claim
36 words
A field emission type electron gun according to claim 1 in which said second detecting means comprises a second comparison circuit for comparing the output voltage of said first voltage source and a reference signal volTage.
Claim 4
Dependent Claim
195 words
A field emission type electron gun comprising: an emitter for emitting an electron beam, a heating means for heating said emitter, a first anode for generating a strong electric field at said emitter, a first voltage source for generating a potential difference between said first anode and said emitter, a second anode located behind the first anode maintained at ground potential, a second high voltage source for supplying negative high potential to said emitter for accelerating said electron beam, a first detecting means for detecting the electron beam emitted from said emitter and providing a signal indicative of the electron beam fluctuation, a comparing means for comparing the output signal of said first detecting means with a reference signal and providing an output signal indicative of the comparison, a control means for controlling the output voltage of said first voltage source in response to the output signal of said comparing means, a second detecting means for detecting the change in output voltage of said first voltage source, and a warning means for indicating the state of crystal buildup on the emitter surface, said warning means responsive to the output signal of said second detecting means.
Claim 5
Dependent Claim
195 words
A field emission type electron gun comprising: an emitter for emitting an electron beam, a heating means for heating said emitter, a first anode for generating a strong electric field at said emitter, a first voltage source for generating a potential difference between said first anode and said emitter, a second anode located behind the first anode maintained at ground potential, a second high voltage source for supplying negative high potential to said emitter for accelerating said electron beam, a first detecting means for detecting the electron beam emitted from said emitter and providing a signal indicative of the electron beam fluctuation, a comparing means for comparing the output signal of said first detecting means with a reference signal and providing an output signal indicative of the comparison, a control means for controlling the output voltage of said first voltage source in response to the output signal of said comparing means, a second detecting means for detecting the change in output voltage of said first voltage source, and a warning means for indicating the state of crystal buildup on the emitter surface, said warning means responsive to the output signal of said second detecting means.
Claim 6
Dependent Claim
209 words
A field emission type electron gun comprising: an emitter for emitting an electron beam, a heating means for heating said emitter, a first anode for generating a strong electric field at said emitter, a first voltage source for generating a potential difference between said first anode and said emitter, a second anode located behind the first anode and maintained at ground potential, a second high voltage source for supplying negative high potential to said emitter for accelerating said electron beam, a first detecting means for detecting the electron beam emitted from said emitter and providing a signal indicative of the electron beam fluctuation, a first comparing means for comparing the output signal of said first detecting means with a reference signal and providing a signal indicative of the comparison, a first control means for controlling the output voltage of said first voltage source in response to the output signal of said first comparing means, a second detecting means for detecting the change in output voltage of said first voltage source and providing an output signal indicative thereof, and a second control means for controlling said heating means in response to the output signal of said second detecting means to restore the emitter tip after deformation due to crystal buildup.
Claim 7
Dependent Claim
209 words
A field emission type electron gun comprising: an emitter for emitting an electron beam, a heating means for heating said emitter, a first anode for generating a strong electric field at said emitter, a first voltage source for generating a potential difference between said first anode and said emitter, a second anode located behind the first anode and maintained at ground potential, a second high voltage source for supplying negative high potential to said emitter for accelerating said electron beam, a first detecting means for detecting the electron beam emitted from said emitter and providing a signal indicative of the electron beam fluctuation, a first comparing means for comparing the output signal of said first detecting means with a reference signal and providing a signal indicative of the comparison, a first control means for controlling the output voltage of said first voltage source in response to the output signal of said first comparing means, a second detecting means for detecting the change in output voltage of said first voltage source and providing an output signal indicative thereof, and a second control means for controlling said heating means in response to the output signal of said second detecting means to restore the emitter tip after deformation due to crystal buildup.
Claim 8
Dependent Claim
43 words
A field emission type electron gun according to claim 4 in which said second control means comprises a timing circuit for controlling the time during which the emitter is heated so as to restore the emitter tip after deformation due to crystal buildup.
Claim 9
Dependent Claim
222 words
A field emission type electron gun comprising: an emitter for emitting an electron beam, a heating means for heating said emitter, a first anode for generating a strong electric field at said emitter, a first voltage source for generating a potential difference between said first anode and said emitter, a second anode located behind the first anode and maintained at ground potential, a second high voltage source for supplying negative high potential to said emitter for accelerating said electron beam, a first detecting means for detecting the electron beam emitted from said emitter and providing a signal indicative of electron beam fluctuation, a comparing means for comparing the output signal of said first detecting means with a reference signal and providing an output signal indicative of the comparison, a first control means for controlling the output voltage of said first voltage source in response to the output signal of said comparing means, a second detecting means for detecting the change in output voltage of said first voltage source anD providing an output signal indicative thereof, a second control means for controlling said heating means in response to the output signal of said second detecting means, and a switching means arranged between said emitter and said first anode, said switching means controlled in response to the output signal of said second detecting means.
Claim 10
Dependent Claim
222 words
A field emission type electron gun comprising: an emitter for emitting an electron beam, a heating means for heating said emitter, a first anode for generating a strong electric field at said emitter, a first voltage source for generating a potential difference between said first anode and said emitter, a second anode located behind the first anode and maintained at ground potential, a second high voltage source for supplying negative high potential to said emitter for accelerating said electron beam, a first detecting means for detecting the electron beam emitted from said emitter and providing a signal indicative of electron beam fluctuation, a comparing means for comparing the output signal of said first detecting means with a reference signal and providing an output signal indicative of the comparison, a first control means for controlling the output voltage of said first voltage source in response to the output signal of said comparing means, a second detecting means for detecting the change in output voltage of said first voltage source anD providing an output signal indicative thereof, a second control means for controlling said heating means in response to the output signal of said second detecting means, and a switching means arranged between said emitter and said first anode, said switching means controlled in response to the output signal of said second detecting means.
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) | 1977-07-22 | 1978-01-21 | 1978-07-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-22 | 1982-01-21 | 1982-07-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-22 | 1986-01-21 | 1986-07-23 | $7700.00 | Window Closed / Lapsed |