GB2269267A - Focusing means for cathode ray tubes - Google Patents

Focusing means for cathode ray tubes

Info

Publication number
GB2269267A
GB2269267A GB9317203A GB9317203A GB2269267A GB 2269267 A GB2269267 A GB 2269267A GB 9317203 A GB9317203 A GB 9317203A GB 9317203 A GB9317203 A GB 9317203A GB 2269267 A GB2269267 A GB 2269267A
Authority
GB
United Kingdom
Prior art keywords
potential
anode
anodes
grid
cathode
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB9317203A
Other versions
GB9317203D0 (en
GB2269267B (en
Inventor
John Randolph Banbury
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
UK Secretary of State for Defence
Original Assignee
UK Secretary of State for Defence
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from GB919104649A external-priority patent/GB9104649D0/en
Application filed by UK Secretary of State for Defence filed Critical UK Secretary of State for Defence
Priority to GB9317203A priority Critical patent/GB2269267B/en
Publication of GB9317203D0 publication Critical patent/GB9317203D0/en
Publication of GB2269267A publication Critical patent/GB2269267A/en
Application granted granted Critical
Publication of GB2269267B publication Critical patent/GB2269267B/en
Anticipated expiration legal-status Critical
Revoked legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
    • H01J29/48—Electron guns
    • H01J29/488—Schematic arrangements of the electrodes for beam forming; Place and form of the elecrodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement
    • H01J29/58—Arrangements for focusing or reflecting ray or beam
    • H01J29/62—Electrostatic lenses
    • H01J29/626—Electrostatic lenses producing fields exhibiting periodic axial symmetry, e.g. multipolar fields
    • H01J29/628—Electrostatic lenses producing fields exhibiting periodic axial symmetry, e.g. multipolar fields co-operating with or closely associated to an electron gun

Landscapes

  • Eye Examination Apparatus (AREA)

Abstract

A cathode ray tube comprising a cathode (K) for emitting a beam of electrons; a grid (G) for controlling the intensity of the beam; three or more anodes (A1, A3, A4); means for varying the potential of at least one of the anodes (A3) for focusing the beam to form a spot on a screen; and an additional, dynamic focus electrode (A2) maintained generally at a potential close to the cathode/grid potential. Suitable means may be included for applying to said dynamic focus electrode a high frequency signal to provide a rapid focus control means. Said dynamic focus means may comprise a plurality of circumferentially disposed segments and include means for applying a separate high voltage to each segment thus allowing the possibility of creating a quadrupole action in conjunction with at least one adjacent electrode, said segments covered with a deposited high-resistance conducting film to prevent charging effects. Preferably the potential of the first anode (A1) is substancially greater than the controlling voltage range of the grid (G), the potential of the static focus electrode (A3), interposed between the first and final anodes, is substantially equal to or lower than that of the first anode; and the potential of the final anode (A4) is substantially higher than that of the first anode (A1).
GB9317203A 1991-03-05 1992-02-27 Focusing means for cathode ray tubes Revoked GB2269267B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB9317203A GB2269267B (en) 1991-03-05 1992-02-27 Focusing means for cathode ray tubes

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GB919104649A GB9104649D0 (en) 1991-03-05 1991-03-05 Focusing means for cathode ray tubes
GB9317203A GB2269267B (en) 1991-03-05 1992-02-27 Focusing means for cathode ray tubes
PCT/GB1992/000352 WO1992016007A1 (en) 1991-03-05 1992-02-27 Focusing means for cathode ray tubes

Publications (3)

Publication Number Publication Date
GB9317203D0 GB9317203D0 (en) 1993-11-17
GB2269267A true GB2269267A (en) 1994-02-02
GB2269267B GB2269267B (en) 1995-02-15

Family

ID=26298529

Family Applications (1)

Application Number Title Priority Date Filing Date
GB9317203A Revoked GB2269267B (en) 1991-03-05 1992-02-27 Focusing means for cathode ray tubes

Country Status (1)

Country Link
GB (1) GB2269267B (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58198819A (en) * 1982-05-14 1983-11-18 Matsushita Electronics Corp Cathode ray tube manufacturing method
JPS5990343A (en) * 1982-11-15 1984-05-24 Toshiba Corp Electron gun for cathode ray tube
EP0235975A1 (en) * 1986-02-12 1987-09-09 Rca Licensing Corporation CRT and color display system
EP0319328A2 (en) * 1987-12-04 1989-06-07 Rank Brimar Limited Electron guns for cathode ray tubes

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA1237464A (en) * 1984-10-19 1988-05-31 Hsing-Yao Chen Electron gun having a two piece screen grid electrode means

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58198819A (en) * 1982-05-14 1983-11-18 Matsushita Electronics Corp Cathode ray tube manufacturing method
JPS5990343A (en) * 1982-11-15 1984-05-24 Toshiba Corp Electron gun for cathode ray tube
EP0235975A1 (en) * 1986-02-12 1987-09-09 Rca Licensing Corporation CRT and color display system
EP0319328A2 (en) * 1987-12-04 1989-06-07 Rank Brimar Limited Electron guns for cathode ray tubes

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Patent Abstracts of Japan vol.8, no.200 (E-226)(1637)13 Sept1984 & JP,A,59 090 343 *
Patent Abstracts of Japan vol.8, no.44 (E-229)(1481) 25 Feb 1984 & JP,A,58 198 819 *

Also Published As

Publication number Publication date
GB9317203D0 (en) 1993-11-17
GB2269267B (en) 1995-02-15

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Legal Events

Date Code Title Description
773K Patent revoked under sect. 73(2)/1977