US3866077A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electron emitters
Assignee: National Research Development Corp UK
•
Filing: 1972-07-05
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Granted: 1975-02-11
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Expires: 1992-07-05
Abstract
Abstract A carbon filament such as a carbon fibre or graphite whisker is used as a source of field emission electrons in an electronic device such as an electron microscope or an electron beam machining device. A vacuum of only 10 7 torr is required, and electrical noise in the beam may be reduced by momentarily heating the source in vacuum before use, and/or by using an electrical current stabilisation circuit.
Inventors
- 👤 Francis Sidney Baker
- 👤 Charles Richard Harrison
- 👤 Anthony Raymond Osborn
- 👤 John Williams
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 15:35
CPC Classifications
H; H01; H01J; H01J1/00; H01J1/02; H01J1/30; H01J1/304; H01J37/00; H01J37/02; H01J37/04; H01J37/06; H01J37/073; H01J37/24; H01J37/241; H01J2201/00; H01J2201/30; H01J2201/304; H01J2201/30446; H01J2201/30453; H01J2201/30457
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
57 words
An electronic device consisting of an enclosure capable of enclosing a vacuum, a point source which Can emit electrons arranged therein, which source consists essentially of at least one carbon filament having an emitting point, emission control means which can cause electrons to be emitted from the source by field emission, and means for receiving said electrons.
Claim 2
Dependent Claim
57 words
An electronic device consisting of an enclosure capable of enclosing a vacuum, a point source which Can emit electrons arranged therein, which source consists essentially of at least one carbon filament having an emitting point, emission control means which can cause electrons to be emitted from the source by field emission, and means for receiving said electrons.
Claim 3
Dependent Claim
17 words
An electronic device according to claim 1 in which said carbon filament consists of a carbon fibre.
Claim 4
Dependent Claim
17 words
An electronic device according to claim 1 in which said carbon filament consists of a graphite whisker.
Claim 5
Dependent Claim
26 words
An electronic device according to claim 1 in which focusing means are provided to focus electrons from the source onto the means for receiving the electrons.
Claim 6
Dependent Claim
39 words
An electronic device according to claim 1 having a current stabilisation circuit connectable to the means for receiving electrons and which can be arranged to control the emission control means whereby electrical noise emitted by the source is reduced.
Claim 7
Dependent Claim
26 words
An electronic device according to claim 1 having a high electrical resistance in series with the source whereby electrical noise emitted by the source is reduced.
Claim 8
Dependent Claim
27 words
An electronic device according to claim 1 in said filaments have been heated in high vacuum before use, whereby electrical noise emitted by the source is reduced.
Claim 9
Dependent Claim
19 words
An electronic device according to claim 1 wherein the source comprises an array of at least 1,000 carbon filaments.
Claim 10
Dependent Claim
14 words
An electronic device according to claim 1 arranged as an electron beam machining device.
Claim 11
Dependent Claim
12 words
An electronic device according to claim 1 arranged as an electron microscope.
Claim 12
Dependent Claim
72 words
An electronic device consisting of an enclosure capable of enclosing a vacuum, a point source which can emit electrons arranged therein, which source consists essentially of at least one carbon filament having an emitting point said carbon filament being chosen from the group consisting of graphite whisker and carbon fiber, emission control means which can cause electrons to be emitted from the source by field emission, and means for receiving said electrons.
Claim 13
Dependent Claim
72 words
An electronic device consisting of an enclosure capable of enclosing a vacuum, a point source which can emit electrons arranged therein, which source consists essentially of at least one carbon filament having an emitting point said carbon filament being chosen from the group consisting of graphite whisker and carbon fiber, emission control means which can cause electrons to be emitted from the source by field emission, and means for receiving said electrons.
References Cited (Backward Citations)
US1203215A
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US1628045A
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US2272353A
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US3535516A
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US3484643A
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US3532923A
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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) | 1978-02-10 | 1978-08-12 | 1979-02-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-10 | 1982-08-12 | 1983-02-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-10 | 1986-08-12 | 1987-02-11 | $7700.00 | Window Closed / Lapsed |