US3141988A - Electron-gun using combined magnetic and electrostatic focussing - Google Patents

Electron-gun using combined magnetic and electrostatic focussing Download PDF

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Publication number
US3141988A
US3141988A US56924A US5692460A US3141988A US 3141988 A US3141988 A US 3141988A US 56924 A US56924 A US 56924A US 5692460 A US5692460 A US 5692460A US 3141988 A US3141988 A US 3141988A
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US
United States
Prior art keywords
electron
gun
electrode
ferromagnetic
source
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.)
Expired - Lifetime
Application number
US56924A
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English (en)
Inventor
Murphy Bernard Thomas
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.)
US Philips Corp
North American Philips Co Inc
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US Philips Corp
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
Application filed by US Philips Corp filed Critical US Philips Corp
Application granted granted Critical
Publication of US3141988A publication Critical patent/US3141988A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • H01J29/58—Arrangements for focusing or reflecting ray or beam
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J23/00—Details of transit-time tubes of the types covered by group H01J25/00
    • H01J23/02—Electrodes; Magnetic control means; Screens
    • H01J23/06—Electron or ion guns
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J3/00—Details of electron-optical or ion-optical arrangements or of ion traps common to two or more basic types of discharge tubes or lamps
    • H01J3/02—Electron guns
    • H01J3/027—Construction of the gun or parts thereof

Definitions

  • This invention relates to electron-guns such as are used in electron-beam tubes, e.g. travelling wave tubes for forming the electron-beam.
  • the invention is particularly directed towards the arrangement of beam-forming electrodes and focusing members forming part of the electron-gun.
  • an electron-gun comprises a ferromagnetic focusing member and a beam-forming electrode, the said electrode being formed by a metal surface on a portion of a face of the said focusing member adjacent the electron-beam.
  • the focusing member is substantially circular and has a central aperture for the passage of the electron-beam.
  • FIG. 1 is an elevation view in section of an embodiment of an electron-gun
  • FIG. 2 is an elevational view in section of another embodiment of an electron-gun according to the invention.
  • the electrode-assembly of an electron-gun is disposed within a glass envelope 1 only part of which is illustrated.
  • the electron-gun comprises a cathode indicated generally at 2 and having an electronemissive end face 4.
  • a beam-forming electrode 5 is arranged forward of the cathode end face 4 and a ferromagnetic beam-focusing member 3 is arranged forward of the electrode 5, this member 3 having a central aperture through which the electron-beam passes.
  • the member 3 serves to focus the electron-beam and forms part of a magnetic circuit which includes an annulus 7 sealed to the envelope 1 adjacent the member 3.
  • the remainder of the magnetic circuit is not shown since it is conventional and is described, for example, in British Patents 833,687 and 845,000.
  • an electrode 6 formed by metal deposited upon the ferromagnetic member 3.
  • the ferromagnetic member is an alloy, which usually will be the case, this electrode 6 may comprise a copper-plated surface formed upon the member 3.
  • the member 3 is a ferromagnetic ferrite the surface may be formed by copper-plating or, if desired, by a metal spraying process.
  • this deposition of the electrode 6 affords a simpler method of providing the electrode than the known arrangement of supporting the electrode separately from ceramic spaces such as will be provided for supporting the electrode 5.
  • the electrode 6 may be built up to the desired profile by successive plating or metal-spraying operations and subsequent machining.
  • FIGURE 2 illustrates a second embodiment wherein the ferromagnetic member 3 is in the form of a disc hav- 3,141,988 Patented July 21, 1964 ing a dished central portion with an aperture through which the electron beam is arranged to pass.
  • An electrode 6 is formed upon the face of the member 3 nearer to the cathode 2, the electrode 6 in this embodiment having a profile much the same as that of the said face of the member 3.
  • the electron-gun also includes a second ferromagnetic member 8 which is provided with an electrode 5 which is formed on the surface of the member 4 facing the electrode 6.
  • the profile of the electrode 5 is substantially the same as that of the face of the member 4 upon which it is formed but it will be appreciated that, if these two profiles were required to be different, then the profile of the member 5 could be determined by plating or metal-spraying processes, followed by subsequent machining, in a manner similar to that outlined above in respect of the embodiment shown in FIGURE 1.
  • the electron-gun according to the invention is particularly useful in travelling-wave tubes where it is used in a Pierce type immersed field, or as it is sometimes known, a confined flow gun, i.e. in this type of electron gun, the magnetic field extends from the electronemissive surface of the cathode and the lines of magnetic force lie parallel to the direction of electron flow from the cathode to the first anode.
  • An electron-gun assembly for an electron discharge tube comprising a source of electrons, a circular discshaped ferromagnetic member spaced from said source of electrons and provided with a central aperture through which passes a beam of electrons derived from said source, and a metal layer on a portion of a surface of said ferromagnetic member adjacent the electron beam surrounding said aperture and facing said electron source serving as a beam-focusing electrode.
  • An electron-gun as claimed in claim 1 wherein a strip of metal is provided on the focusing member which extends from the electrode to a portion of the focusing member remote from the electron-beam.

Landscapes

  • Microwave Tubes (AREA)
  • Electrodes For Cathode-Ray Tubes (AREA)
  • Electron Sources, Ion Sources (AREA)
  • Refuge Islands, Traffic Blockers, Or Guard Fence (AREA)
US56924A 1959-09-23 1960-09-19 Electron-gun using combined magnetic and electrostatic focussing Expired - Lifetime US3141988A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB32396/59A GB915812A (en) 1959-09-23 1959-09-23 Improvements in electron-guns

Publications (1)

Publication Number Publication Date
US3141988A true US3141988A (en) 1964-07-21

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ID=10337973

Family Applications (1)

Application Number Title Priority Date Filing Date
US56924A Expired - Lifetime US3141988A (en) 1959-09-23 1960-09-19 Electron-gun using combined magnetic and electrostatic focussing

Country Status (4)

Country Link
US (1) US3141988A (en(2012))
DE (2) DE1231358B (en(2012))
GB (1) GB915812A (en(2012))
NL (1) NL255680A (en(2012))

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3225248A (en) * 1961-05-27 1965-12-21 United Aircraft Corp Device for producing a high-intensity beam of charge carriers of small aperture
US5109179A (en) * 1989-01-17 1992-04-28 Thomson Tubes Electroniques Electron gun provided with a device producing a magnetic field in the neighborhood of a cathode

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2486856A (en) * 1947-04-12 1949-11-01 Gen Electric Electron lens
US3098942A (en) * 1955-02-24 1963-07-23 Zenith Radio Corp Magnetic centering device for cathode ray tubes

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1032420B (de) * 1949-11-30 1958-06-19 Loewe Opta Ag Kathodenstrahlroehre

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2486856A (en) * 1947-04-12 1949-11-01 Gen Electric Electron lens
US3098942A (en) * 1955-02-24 1963-07-23 Zenith Radio Corp Magnetic centering device for cathode ray tubes

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3225248A (en) * 1961-05-27 1965-12-21 United Aircraft Corp Device for producing a high-intensity beam of charge carriers of small aperture
US5109179A (en) * 1989-01-17 1992-04-28 Thomson Tubes Electroniques Electron gun provided with a device producing a magnetic field in the neighborhood of a cathode

Also Published As

Publication number Publication date
GB915812A (en) 1963-01-16
DE6606171U (de) 1970-10-01
DE1231358B (de) 1966-12-29
NL255680A (en(2012))

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