US3665241A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Field ionizer and field emission cathode structures and methods of production
Assignee: SRI International Inc
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Filing: 1970-07-13
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Granted: 1972-05-23
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Expires: 1990-07-13
Abstract
Abstract Field-forming devices primarily useful as field ionizers and field emission cathodes and having as a basic element an array of closely spaced cones with sharp points supported on a substrate (in the most usual case conductive or semiconductive) are disclosed. Preferably, the field-forming structure is completed by a screen-like structure, e.g. as fine mesh screen, insulatively supported above the points with the center of apertures in the screen substantially aligned with the longitudinal axis of corresponding cones. A novel method of forming such structures includes placing a screen with a mesh corresponding to the desired number and packing density of sharp conical points in close proximity to, or in contact with, the substrate and projecting material through the screen onto the substrate whereby sharp cones of the material are formed on the substrates.
Inventors
- 👤 Charles A Spindt
- 👤 Louis N Heynick
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 09:24
CPC Classifications
H; H01; H01J; H01J49/00; H01J49/02; H01J49/10; H01J49/16; H01J49/168; H01J1/00; H01J1/02; H01J1/30; H01J1/304; H01J1/3042; H01J27/00; H01J27/02; H01J27/26; H01J35/00; H01J35/02; H01J35/04; H01J35/06; H01J35/065; H01T; H01T23/00; H01J2237/00; H01J2237/06; H01J2237/08; H01J2237/0802; H01J2237/0807
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
70 words
An electric field-forming device consisting of a plate-like substrate and a multiplicity of sharp needle-like elements located on one surface of said substrate, said needle-like elements being highly uniform in shape and uniformly spaced on said substrate said substrate and at least one portion of said needle-like elements being of conductive material and the other portion of said needle-like elements being of a higher resistivity material than said plate-like substrate.
Claim 2
Dependent Claim
70 words
An electric field-forming device consisting of a plate-like substrate and a multiplicity of sharp needle-like elements located on one surface of said substrate, said needle-like elements being highly uniform in shape and uniformly spaced on said substrate said substrate and at least one portion of said needle-like elements being of conductive material and the other portion of said needle-like elements being of a higher resistivity material than said plate-like substrate.
Claim 3
Dependent Claim
30 words
An electric field-forming device as defined in claim 1 wherein said needle-like elements each have a substantially cylindrical pedestal on said substrate and an essentially conical portion on said pedestal.
Claim 4
Dependent Claim
38 words
An electric field-forming device as defined in claim 2 wherein said needle-like elements and said plate-like substrate are conductive and the said pedestal is of a higher resistivity material than either said second electrode or said conical portion.
Claim 5
Dependent Claim
113 words
An electric field-producing structure comprising first and second conductive electrodes and an insulator separating and insulating said first and second electrodes from each other, said first electrode comprising a conductive plate-like screen member having a plurality of apertures therethrough, said second electrode comprising a conductive plate-like member having a plurality of individual needle-like conical members projecting from one surface thereof and said insulator supporting said electrodes only at their outer periphery in such a manner that said needle-like conical members of said second electrode project toward said first electrode and at least some of said needle-like members are positioned with a projection of their longitudinal axes extending through apertures in said first electrode.
Claim 6
Dependent Claim
113 words
An electric field-producing structure comprising first and second conductive electrodes and an insulator separating and insulating said first and second electrodes from each other, said first electrode comprising a conductive plate-like screen member having a plurality of apertures therethrough, said second electrode comprising a conductive plate-like member having a plurality of individual needle-like conical members projecting from one surface thereof and said insulator supporting said electrodes only at their outer periphery in such a manner that said needle-like conical members of said second electrode project toward said first electrode and at least some of said needle-like members are positioned with a projection of their longitudinal axes extending through apertures in said first electrode.
Claim 7
Dependent Claim
52 words
An electric field-producing structure as defined in claim 4 wherein said first and second electrodes are spaced further apart at their outer periphery than in the central portion where said conical members and apertures occur whereby said insulating member is thicker than the electrode spacing at said center portion of said electrodes.
Claim 8
Dependent Claim
35 words
An electric field-producing structure as defined in claim 4 wherein each of said individual needle-like conical members has its longitudinal axis in substantial alignment with the center of a corresponding aperture in said first electrode.
Claim 9
Dependent Claim
52 words
An electric field-producing structure as defined in claim 6 wherein said first and second electrodes are spaced further apart at their outer periphery than in the central portion where said conical members and apertures occur whereby said insulating member is thicker than the electrode spacing at said center portion of said electrodes.
Claim 10
Dependent Claim
34 words
A field-ionizing device including a structure as defined in claim 4 and means for applying a potential source between said first and second electrodes with said second electrode positive relative to said first electrode.
Claim 11
Dependent Claim
33 words
A field-ionizing device including the structure defined in claim 5 and means for applying a potential source between said first and second electrodes with said second electrode positive relative to said first electrode.
Claim 12
Dependent Claim
33 words
A field-ionizing device including the structure defined in claim 6 and means for applying a potential source between said first and second electrodes with said second electrode positive relative to said first electrode.
Claim 13
Dependent Claim
33 words
A field-ionizing device including the structure defined in claim 7 and means for applying a potential source between said first and second electrodes with said second electrode positive relative to said first electrode.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-05-23 | 1975-11-22 | 1976-05-23 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-23 | 1979-11-22 | 1980-05-23 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-23 | 1983-11-22 | 1984-05-23 | $7700.00 | Window Closed / Lapsed |