US5550435A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Field emission cathode apparatus
Assignee: NEC Corp
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Filing: 1994-10-28
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Granted: 1996-08-27
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Expires: 2014-10-28
Abstract
Abstract It is the object of the invention to provide a field emission cathode apparatus comprising plural electron-emitters which eliminates nonuniformity of electric emission density over an emissive area, controls emission currents by active devices, and improves reliability of the apparatus. P-type silicon 5 and n-type silicon 4 are formed on n + -type silicon 6. On n-type silicon 4, an electron-emitter 1 made of Mo is formed, and electron-emitter 1 is surrounded by a grid electrode 2 and an insulator layer 3. N-type silicon 4 serves as a channel region of a junction gate field effect transistor, and a current flowing through it is controlled by a voltage applied to p-type silicon 5. Accordingly, an electron current emitted from electron-emitter 1 is also controlled by this transistor, and by setting up an operation region of this transistor in a saturation current region, nonuniformity of electron emissions from electron-emitters can be improved. Even when a portion of cathodes is damaged, the damage is not magnified to the whole apparatus, and the life of the field emission cathode can be prolonged.
Inventors
- 👤 Toshihide Kuriyama
- 👤 Hideo Makishima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 12:11
CPC Classifications
H; H01; H01J; H01J17/00; H01J17/38; H01J17/40; H01J1/00; H01J1/02; H01J1/30; H01J1/304; H01J1/3042; H01J2201/00; H01J2201/30; H01J2201/319
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
76 words
A field emission cathode apparatus, comprising: an electron-emitter having a micropoint at a tip portion thereof; an active device connected in series to said electron-emitter; and means for applying a predetermined voltage across said electron-emitter and said active device to emit electrons from said micropoint of said electron-emitter; wherein a current flowing through said electron-emitter is modulated by said active device; and said active device has a breakdown voltage that is greater than said predetermined voltage.
Claim 2
Dependent Claim
76 words
A field emission cathode apparatus, comprising: an electron-emitter having a micropoint at a tip portion thereof; an active device connected in series to said electron-emitter; and means for applying a predetermined voltage across said electron-emitter and said active device to emit electrons from said micropoint of said electron-emitter; wherein a current flowing through said electron-emitter is modulated by said active device; and said active device has a breakdown voltage that is greater than said predetermined voltage.
Claim 3
Dependent Claim
20 words
A field emission cathode apparatus according to claim 1, wherein said active device is a junction gate field effect transistor.
Claim 4
Dependent Claim
20 words
A field emission cathode apparatus according to claim 1, wherein said active device is an insulated gate field effect transistor.
Claim 5
Dependent Claim
17 words
A field emission cathode apparatus according to claim 1, wherein said active device is a bipolar transistor.
Claim 6
Dependent Claim
25 words
A field emission cathode apparatus, according to claim 4, wherein: said bipolar transistor includes an emitter-collector path that is connected in series to said electron-emitter.
Claim 7
Dependent Claim
25 words
The field emission cathode apparatus according to claim 2, wherein a source-drain path of said active device is connected in series to said electron emitter.
Claim 8
Dependent Claim
24 words
The field emission cathode apparatus of claim 3, wherein a source-drain path of said active device is connected in series to said electron emitter.
Claim 9
Dependent Claim
37 words
The field emission cathode apparatus of claim 1, further comprising an n-type silicon located under said electron-emitter so that said n-type silicon provides a pinch-off resistance to limit short circuit current when there is a short circuit.
Claim 10
Dependent Claim
88 words
A field emission cathode apparatus, comprising: an electron-emitter having a micropoint at a tip portion thereof; a grid electrode; an active device connected in series to said electron-emitter; and means for applying a predetermined voltage across said grid electrode and an n + -type source of said active device to emit electrons from said micropoint of said electron emitter; wherein a current flowing through said electron emitter is modulated by said active device and said active device has a breakdown voltage that is greater than said predetermined voltage.
Claim 11
Dependent Claim
88 words
A field emission cathode apparatus, comprising: an electron-emitter having a micropoint at a tip portion thereof; a grid electrode; an active device connected in series to said electron-emitter; and means for applying a predetermined voltage across said grid electrode and an n + -type source of said active device to emit electrons from said micropoint of said electron emitter; wherein a current flowing through said electron emitter is modulated by said active device and said active device has a breakdown voltage that is greater than said predetermined voltage.
Claim 12
Dependent Claim
29 words
A field emission cathode apparatus according to claim 9, wherein said active device includes an n-type drain and is connected in series to said electron-emitter through said n-type drain.
Claim 13
Dependent Claim
33 words
A field emission cathode apparatus according to claim 9, wherein said active device includes an n + -type collector and is connected in series to said electron-emitter through said n + -type collector.
Claim 14
Dependent Claim
20 words
A field emission cathode apparatus according to claim 9, wherein said active device is a junction gate field effect transistor.
Claim 15
Dependent Claim
20 words
A field emission cathode apparatus according to claim 9, wherein said active device is an insulated gate field effect transistor.
Claim 16
Dependent Claim
17 words
A field emission cathode apparatus according to claim 9, wherein said active device is a bipolar transistor.
Claim 17
Dependent Claim
25 words
A field emission cathode apparatus according to claim 14, wherein said bipolar transistor includes an emitter-collector path that is connected in series to said electron-emitter.
Claim 18
Dependent Claim
38 words
A field emission cathode apparatus according to claim 9, further comprising an n-type silicon located under said electron-emitter so that said n-type silicon provides a pinch-off resistance to limit short circuit current when there is a short circuit.
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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) | 1999-08-27 | 2000-02-26 | 2000-08-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-08-27 | 2004-02-26 | 2004-08-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-08-27 | 2008-02-26 | 2008-08-27 | $7700.00 | Window Closed / Lapsed |