US4641058A
Expired / Lapsed
US
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Electron gun
Assignee: Toshiba Corp
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Filing: 1986-01-03
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Granted: 1987-02-03
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Expires: 2006-01-03
Abstract
Abstract An electron gun is proposed which has a cathode for generating an electron beam and at least three grids, each having an opening. A pre-focusing electron lens and a main focusing electron lens are formed between the grids in the order named from the cathode to the grids. The pre-focusing lens constitutes a first asymmetric electron lens. The main focusing electron lens constitutes a second asymmetric electron lens. The first and second asymmetric electron lenses have focusing actions whose relatively stronger components are effected along directions substantially perpendicular to each other.
Inventors
- 👤 Shinpei Koshigoe
- 👤 Takeshi Fujiwara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 10:25
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/46; H01J29/48; H01J29/50; H01J29/503; H01J29/488
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
110 words
An electron gun arrangement, comprising: a cathode for generating an electron beam; and first, second, third and fourth grids, in order of increasing distance from said cathode, the cathode, first grid and second grid constituting a triode, each grid having an opening therein through which said electron beam can pass, said second and third grids together functioning to provide a first asymmetrical electron lens having a focusing action that is stronger along a vertical direction than along a horizontal direction, said third and fourth grids together functioning to provide a second asymmetrical electron lens having a focusing action that is stronger along said horizontal direction than along said vertical direction.
Claim 2
Dependent Claim
110 words
An electron gun arrangement, comprising: a cathode for generating an electron beam; and first, second, third and fourth grids, in order of increasing distance from said cathode, the cathode, first grid and second grid constituting a triode, each grid having an opening therein through which said electron beam can pass, said second and third grids together functioning to provide a first asymmetrical electron lens having a focusing action that is stronger along a vertical direction than along a horizontal direction, said third and fourth grids together functioning to provide a second asymmetrical electron lens having a focusing action that is stronger along said horizontal direction than along said vertical direction.
Claim 3
Dependent Claim
47 words
An electron gun according to claim 1, wherein said second grid has a horizontally extending groove formed on a side thereof which opposes said third grid, said groove having a bottom surface through which an opening is centrally formed so as to pass the electron beam therethrough.
Claim 4
Dependent Claim
47 words
An electron gun according to claim 1, wherein said third grid has a vertically extending groove formed on a side thereof which opposes said second grid, said groove having a bottom surface through which an opening is centrally formed so as to pass the electron beam therethrough.
Claim 5
Dependent Claim
91 words
An electron gun according to claim 1, wherein said second grid has a horizontally extending groove formed on a side thereof which opposes said third grid, said horizontally extending groove having a bottom surface through which an opening is centrally formed so as to pass the electron beam therethrough, and said third grid has a vertically extending groove formed on a side thereof which opposes said second grid, said vertically extending groove having a bottom surface through which an opening is centrally formed so as to pass the electron beam therethrough.
Claim 6
Dependent Claim
33 words
An electron gun according to claim 1, wherein an opening of said third grid has a vertically elongated elliptical shape and/or said opening of said fourth grid has a horizontally elongated elliptical shape.
Claim 7
Dependent Claim
45 words
An electron gun according to claim 1, wherein an opening of said third grid and/or said fourth grid has a cylindrical edge, said cylindrical edge having a length less than 1/2 of a diameter of said opening of said third grid and/or said fourth grid.
Claim 8
Dependent Claim
112 words
An electron gun arrangement, comprising: a cathode for generating an electron beam; and first, second, third, fourth, fifth and sixth grids, in order of increasing distance from said cathode, the cathode, first grid and second grid constituting a triode, each grid having an opening therein through which said electron beam can pass, said second and third grids together functioning to provide a first asymmetrical electron lens having a focusing action that is stronger along a vertical direction than along a horizontal direction, said fifth and sixth grids together functioning to provide a second asymmetrical electron lens having a focusing action that is stronger along said horizontal direction than along said vertical direction.
Claim 9
Dependent Claim
112 words
An electron gun arrangement, comprising: a cathode for generating an electron beam; and first, second, third, fourth, fifth and sixth grids, in order of increasing distance from said cathode, the cathode, first grid and second grid constituting a triode, each grid having an opening therein through which said electron beam can pass, said second and third grids together functioning to provide a first asymmetrical electron lens having a focusing action that is stronger along a vertical direction than along a horizontal direction, said fifth and sixth grids together functioning to provide a second asymmetrical electron lens having a focusing action that is stronger along said horizontal direction than along said vertical direction.
Claim 10
Dependent Claim
47 words
An electron gun according to claim 7, wherein said second grid has a horizontally extending groove formed on a side thereof which opposes said third grid, said groove having a bottom surface through which an opening is centrally formed so as to pass the electron beam therethrough.
Claim 11
Dependent Claim
47 words
An electron gun according to claim 7, wherein said third grid has a vertically extending groove formed on a side thereof which opposes said second grid, said groove having a bottom surface through which an opening is centrally formed so as to pass the electron beam therethrough.
Claim 12
Dependent Claim
91 words
An electron gun according to claim 7, wherein said second grid has a horizontally extending groove formed on a side thereof which opposes said third grid, said horizontally extending groove having a bottom surface through which an opening is centrally formed so as to pass the electron beam therethrough, and said third grid has a vertically extending groove formed on a side thereof which opposes said second grid, said vertically extending groove having a bottom surface through which an opening is centrally formed so as to pass the electron beam therethrough.
Claim 13
Dependent Claim
33 words
An electron gun according to claim 7, wherein an opening of said fifth grid has a vertically elongated elliptical shape and/or an opening of said sixth grid has a horizontally elongated elliptical shape.
Claim 14
Dependent Claim
45 words
An electron gun according to claim 7, wherein an opening of said fifth grid and/or said sixth grid has a cylindrical edge, said cylindrical edge having a length less than 1/2 of a diameter of said opening of said fifth grid and/or said sixth grid.
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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) | 1990-02-02 | 1990-08-04 | 1991-02-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-02-02 | 1994-08-04 | 1995-02-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-02-02 | 1998-08-04 | 1999-02-03 | $7700.00 | Window Closed / Lapsed |