US3755704A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Field emission cathode structures and devices utilizing such structures
Assignee: SRI International Inc
•
Filing: 1970-02-06
•
Granted: 1973-08-28
•
Expires: 1990-02-06
Abstract
Abstract Vacuum devices incorporate electron or field forming sources formed by a cellular array of emission sites. The sources comprise a metal/insulator/metal film sandwich on a substrate with a cellular array of holes through the upper metal and insulator, leaving the edges of the upper metal electrode effectively exposed to the upper surface of the lower metal electrode. Sharp protuberances directed toward the upper electrode and constituting emitter tips of controlled configurations are formed on the exposed area of the lower electrode. A method of forming the structure includes starting with the metal/insulator/metal film sandwich having the cellular array of holes already formed and directing permanent electrode material into the cellular array of holes and masking or subsequently removable material onto the surface surrounding the holes whereby an individual sharp cone-like emitter is formed within each of the holes in the cellular array. Vacuum devices are formed from such structures. For example, a diode is formed either by making the masking material over each emission site an electrode or by removing the masking material and applying a conductive electrode material over each emission site.
Inventors
- 👤 C Spindt
- 👤 K Shoulders
- 👤 L Heynick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 05:29
CPC Classifications
H; H01; H01J; H01J9/00; H01J9/02; H01J9/022; H01J9/025; H01J1/00; H01J1/02; H01J1/30; H01J1/304; H01J1/3042; H01J2201/00; H01J2201/30; H01J2201/319
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
68 words
An electron tube comprising first and second conductive electrodes insulatingly spaced from and substantially parallel to each other, said electrodes sealed in vacuum-tight relationship, said first conductive electrode opposed and exposed to a surface of said second electrode, and a single individual needle-like protuberance on said second electrode projecting toward said first electrode, said single individual needle-like protuberance being of a higher resistivity material than said second electrode.
Claim 2
Dependent Claim
68 words
An electron tube comprising first and second conductive electrodes insulatingly spaced from and substantially parallel to each other, said electrodes sealed in vacuum-tight relationship, said first conductive electrode opposed and exposed to a surface of said second electrode, and a single individual needle-like protuberance on said second electrode projecting toward said first electrode, said single individual needle-like protuberance being of a higher resistivity material than said second electrode.
Claim 3
Dependent Claim
44 words
An electron tube as defined in claim 1 wherein a control electrode is located between, parallel to and insulatingly separated from both said first and second electrodes, said control electrode is provided with an aperture substantially coaxial with the axis of said needle-like protuberance.
Claim 4
Dependent Claim
122 words
An electric field producing structure comprising first and second conductive electrodes insulatingly spaced from and substantially parallel to each other, said first conductive electrode having at least one aperture therethrough whereby edges of said first electrode are exposed to a surface of said second electrode, and a single individual needle-like protuberance on said second electrode under each aperture in said first conductive electrode, each said individual needle-like protuberances projecting toward said first electrode and located substantially coaxially with its corresponding aperture in said first electrode, said needle-like protuberance having a substantially cylindrical pedestal on said second electrode and an essentially conical portion on said pedestal, said pedestal being of a higher resistivity material than either said second electrode or said conical portion.
Claim 5
Dependent Claim
122 words
An electric field producing structure comprising first and second conductive electrodes insulatingly spaced from and substantially parallel to each other, said first conductive electrode having at least one aperture therethrough whereby edges of said first electrode are exposed to a surface of said second electrode, and a single individual needle-like protuberance on said second electrode under each aperture in said first conductive electrode, each said individual needle-like protuberances projecting toward said first electrode and located substantially coaxially with its corresponding aperture in said first electrode, said needle-like protuberance having a substantially cylindrical pedestal on said second electrode and an essentially conical portion on said pedestal, said pedestal being of a higher resistivity material than either said second electrode or said conical portion.
Claim 6
Dependent Claim
23 words
An electric field producing structure as defined in claim 3 including a third electrode parallel to and insulatingly spaced from said first electrode.
Claim 7
Dependent Claim
25 words
An electric field producing structure as defined in claim 3 wherein said individual needle-like protuberances are of a higher resistivity material than said second electrode.
Claim 8
Dependent Claim
91 words
An electric field producing structure comprising first and second conductive electrodes insulatingly spaced from and substantially parallel to each other, said first conductive electrode having a plurality of apertures therethrough whereby edges of said first electrode are exposed to said surface of said second electrode, and a plurality of single individual needle-like protuberances on said second electrode each projecting toward said first electrode and located substantially coaxially with its corresponding aperture in said first electrode, said needle-like protuberances being constituted of a material of substantially higher resistivity than said second electrode.
Claim 9
Dependent Claim
91 words
An electric field producing structure comprising first and second conductive electrodes insulatingly spaced from and substantially parallel to each other, said first conductive electrode having a plurality of apertures therethrough whereby edges of said first electrode are exposed to said surface of said second electrode, and a plurality of single individual needle-like protuberances on said second electrode each projecting toward said first electrode and located substantially coaxially with its corresponding aperture in said first electrode, said needle-like protuberances being constituted of a material of substantially higher resistivity than said second electrode.
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) | 1976-08-27 | 1977-02-26 | 1977-08-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-27 | 1981-02-26 | 1981-08-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-27 | 1985-02-26 | 1985-08-28 | $7700.00 | Window Closed / Lapsed |