US3924153A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electron gun
Assignee: Westinghouse Electric Corp
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Filing: 1974-03-11
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Granted: 1975-12-02
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Expires: 1994-03-11
Abstract
Abstract An electron gun structure for cathode ray tubes, particularly cathode ray tubes employing high quantum efficiency silicon as a photoconductor target. Electrons from a cathode are formed into an electron beam of high current density with small beam diameter by means of a specially-shaped control grid and anode, together with a cylindrical focus electrode between the control grid and anode which prevents the electrons in the beam from diverging due to mutual electrostatic repulsion.
Inventors
- 👤 James L Mcintyre
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 02:38
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/46; H01J29/48; H01J29/488
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
169 words
In a cathode ray tube, an electron gun structure comprising a cathode for emitting an electron beam, said cathode comprising a layer of an oxide having a smooth shaved surface from which electrons are emitted, a dish-shaped control grid having a central aperture through which electrons from said cathode can pass and in which the convex side of the dish-shaped grid faces said cathode, a dish-shaped accelerating anode spaced ahead of said control grid in the path of travel of said electrons from said cathode and having a central aperture at the bottom of its dish-shaped configuration through which electrons can pass, the concave side of the dish-shaped accelerating anode facing said control grid, a generally annular focus electrode surrounding said electron beam between the control grid and said accelerating anode, means connecting said cathode to ground potential, means for applying a positive potential to said control grid and said accelerating anode, and means for applying to said focusing electrode a potential ranging from zero to a negative potential.
Claim 2
Dependent Claim
169 words
In a cathode ray tube, an electron gun structure comprising a cathode for emitting an electron beam, said cathode comprising a layer of an oxide having a smooth shaved surface from which electrons are emitted, a dish-shaped control grid having a central aperture through which electrons from said cathode can pass and in which the convex side of the dish-shaped grid faces said cathode, a dish-shaped accelerating anode spaced ahead of said control grid in the path of travel of said electrons from said cathode and having a central aperture at the bottom of its dish-shaped configuration through which electrons can pass, the concave side of the dish-shaped accelerating anode facing said control grid, a generally annular focus electrode surrounding said electron beam between the control grid and said accelerating anode, means connecting said cathode to ground potential, means for applying a positive potential to said control grid and said accelerating anode, and means for applying to said focusing electrode a potential ranging from zero to a negative potential.
Claim 3
Dependent Claim
44 words
The electron gun structure of claim 1 including a beam limiting aperture through which said electron beam passes and positioned on the side of said accelerating anode opposite said control grid, and means connecting said beam limiting aperture to a source of positive potential.
Claim 4
Dependent Claim
25 words
The electron gun structure of claim 2 wherein a source of +300 volts is connected to said accelerating anode and to said beam limiting aperture.
Claim 5
Dependent Claim
41 words
The electron gun structure of claim 1 wherein said control grid and accelerating anode have cylindrical portions connected to and integral with dish-shaped portions, the diameters of said cylindrical portions being substantially equal to the maximum diameters of said dish-shaped portions.
Claim 6
Dependent Claim
29 words
The electron gun structure of claim 4 wherein the diameter of said focus electrode is greater than that of said cylindrical portions of the control grid and accelerating anode.
Claim 7
Dependent Claim
36 words
The electron gun structure of claim 1 wherein said cathode has a dish-shaped portion which receives said oxide layer, the smooth shaved surface of the oxide layer facilitating emission of electrons over substantially its entire surface.
Claim 8
Dependent Claim
22 words
The electron gun structure of claim 1 wherein said smooth shaved surface has a smoothness of at least 20 microinches or less.
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) | 1978-12-01 | 1979-06-02 | 1979-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-01 | 1983-06-02 | 1983-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-01 | 1987-06-02 | 1987-12-02 | $7700.00 | Window Closed / Lapsed |