US3863091A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electron gun assembly with improved unitary lens system
Assignee: Hitachi Ltd
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Filing: 1972-12-29
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Granted: 1975-01-28
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Expires: 1992-12-29
Abstract
Abstract An electron gun assembly for use in a cathode ray tube provided with a main lens system for focusing electrons emitted from a cathode electrode, comprising at least three focusing electrodes aligned on the same imaginary axis extending from said cathode electrode to form with an anode electrode at least two separated lenses on said axis when voltages are applied. The two lenses form a unitary lens having a large aperture in which the object point (i.e., cross-over point) for the lens formed of a first and a second grid electrode is located at the focal position of the lens on the cathode side and the trace of the emitted electron beam becomes nearly parallel with said axis between said two lenses. Thus, the radius of the resulting beam spot becomes smaller and the focusing characteristics are improved.
Inventors
- 👤 Toshio Hurukawa
- 👤 Eiichi Yamazaki
- 👤 Hiromi Kanai
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 14:59
CPC Classifications
H; H01; H01J; H01J29/00; H01J29/46; H01J29/58; H01J29/62; H01J29/622; H01J29/624; H01J29/48; H01J29/488
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
149 words
An electron gun assembly for use in a cathode ray tube having at least one electron gun provided with a prefocusing lens system and a main lens system for focusing an electron beam emitted from at least one cathode on a fluorescent screen, said main lens system comprising at least two individual lens systems each formed of a plurality of aligned lens electrodes whose axes correspond to the central axis of said electron gun, said main lens system being positioned with respect to said prefocusing lens system so that the cross-over point of said electron beam is positioned substantially at the focal point of the individual lens system closest to said cathode, thereby causing said electron beam to have a substantially uniform transverse dimension of flux and a central axis in parallel with the axis of said electron gun between said individual lens systems forming said main lens system.
Claim 2
Dependent Claim
149 words
An electron gun assembly for use in a cathode ray tube having at least one electron gun provided with a prefocusing lens system and a main lens system for focusing an electron beam emitted from at least one cathode on a fluorescent screen, said main lens system comprising at least two individual lens systems each formed of a plurality of aligned lens electrodes whose axes correspond to the central axis of said electron gun, said main lens system being positioned with respect to said prefocusing lens system so that the cross-over point of said electron beam is positioned substantially at the focal point of the individual lens system closest to said cathode, thereby causing said electron beam to have a substantially uniform transverse dimension of flux and a central axis in parallel with the axis of said electron gun between said individual lens systems forming said main lens system.
Claim 3
Dependent Claim
147 words
In a cathode ray tube having at least one electron gun assembly provided with a prefocusing lens system and a main lens system for focusing an electron beam emitted from at least one cathode on a fluorescent screen, said main lens system comprising at least two electron lens systems aligned on a common central axis with said cathode, each electron lens system being formed of a plurality of aligned lens electrodes and meams for connecting potential sources to the respective lens electrodes, said main lens system being positioned with respect to said cathode so that the cross-over point of the electron beam emitted from said cathode is positioned substantially at the focal point of the electron lens system of said main lens system closest to the cathode, thereby collimating the electron beam substantially parallel to said common central axis of said main lens system between said two
Claim 4
Dependent Claim
147 words
In a cathode ray tube having at least one electron gun assembly provided with a prefocusing lens system and a main lens system for focusing an electron beam emitted from at least one cathode on a fluorescent screen, said main lens system comprising at least two electron lens systems aligned on a common central axis with said cathode, each electron lens system being formed of a plurality of aligned lens electrodes and meams for connecting potential sources to the respective lens electrodes, said main lens system being positioned with respect to said cathode so that the cross-over point of the electron beam emitted from said cathode is positioned substantially at the focal point of the electron lens system of said main lens system closest to the cathode, thereby collimating the electron beam substantially parallel to said common central axis of said main lens system between said two
Claim 5
Dependent Claim
38 words
An electron gun assembly according to claim 2, in which said two electron lens systems have a common electrode disposed between said two lens systems, the axial length of said common electrode being larger than the diameter thereof.
Claim 6
Dependent Claim
28 words
An electron gun assembly according to claim 2, in which said two lens systems are formed of one bipotential type lens system and one unipotential type lens system.
Claim 7
Dependent Claim
23 words
An electron gun assembly according to claim 2, in which both of said two lens systems are formed of bipotential type lens systems.
Claim 8
Dependent Claim
23 words
An electron gun assembly according to claim 2, in which both of said two lens systems are formed of unipotential type lens systems.
Claim 9
Dependent Claim
58 words
An electron gun assembly according to claim 4, wherein said two electron lens systems are formed of successively aligned first, second, third, fourth, fifth and sixth electrodes on the same axis as said cathode, said third and fourth electrodes forming a bipotential type lens system, and said fourth, fifth and sixth electrodes forming a unipotential type lens system.
Claim 10
Dependent Claim
23 words
An electron gun assembly according to claim 7, in which the axial length of said fourth electrode is larger than the diameter thereof.
Claim 11
Dependent Claim
50 words
An electron gun assembly according to claim 5, wherein said two electron lens systems are formed of successively aligned first, second, third, fourth and fifth electrodes on the same axis as said cathode, said third and fourth electrodes and said fourth and fifth electrodes forming respective bipotential type lens systems.
Claim 12
Dependent Claim
23 words
An electron gun assembly according to claim 9, in which the axial length of said fOurth electrode is larger than the diameter thereof.
Claim 13
Dependent Claim
54 words
An electron gun assembly according to claim 6, wherein said two electron lens systems are formed of successively aligned first, second, third, fourth, fifth, sixth and seventh electrodes on the same axis as said cathode, said third, fourth and fifth electrodes and said fifth, sixth and seventh electrodes forming respective unipotential type lens systems.
Claim 14
Dependent Claim
23 words
An electron gun assembly according to claim 11, in which the axial length of said fifth electrode is larger than the diameter thereof.
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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) | 1978-01-27 | 1978-07-29 | 1979-01-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-01-27 | 1982-07-29 | 1983-01-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-01-27 | 1986-07-29 | 1987-01-28 | $7700.00 | Window Closed / Lapsed |