JPS57187843A - Magnetic focusing crt unit - Google Patents

Magnetic focusing crt unit

Info

Publication number
JPS57187843A
JPS57187843A JP7226681A JP7226681A JPS57187843A JP S57187843 A JPS57187843 A JP S57187843A JP 7226681 A JP7226681 A JP 7226681A JP 7226681 A JP7226681 A JP 7226681A JP S57187843 A JPS57187843 A JP S57187843A
Authority
JP
Japan
Prior art keywords
permanent magnet
magnetic field
centered
outer circumference
inner circumference
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
JP7226681A
Other languages
Japanese (ja)
Other versions
JPH0316732B2 (en
Inventor
Taketoshi Shimoma
Kumio Fukuda
Toshio Shimaougi
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.)
Toshiba Corp
Original Assignee
Toshiba Corp
Tokyo Shibaura Electric Co Ltd
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 Toshiba Corp, Tokyo Shibaura Electric Co Ltd filed Critical Toshiba Corp
Priority to JP7226681A priority Critical patent/JPS57187843A/en
Publication of JPS57187843A publication Critical patent/JPS57187843A/en
Publication of JPH0316732B2 publication Critical patent/JPH0316732B2/ja
Granted 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
    • H01J29/58—Arrangements for focusing or reflecting ray or beam
    • H01J29/64—Magnetic lenses
    • H01J29/68—Magnetic lenses using permanent magnets only

Abstract

PURPOSE:To correct variations of a focusing state by controllng from outside a tube an electron beam focusing magnetic field generated by a permanent magnet stored in the tube. CONSTITUTION:A magnetic field regulating element 41 made of a highly magnetic material is arranged outside an asymmetric permanent magnet 40 with its inner circumference 42 and outer circumference 43 off-centered in the direction the outer circumference is off-centered. The section 40a to which the permanent magnet 40 is off-centered is made thick in thickness, while the opposite section 40b is made thin on the contrary. The magnetic field regulating element 41 concentrates a part of the magnetic field mainly generated by the 40a portion so as to demagnetize in appearance, and the permanent magnet 40 is thus made symmetrical in essence in relation to the central axis of the inner circumference 42. Therefore, occurrence of coma astigmatism, etc. of the beam spot due to the eccentricity between the outer circumference and the inner circumference of the permanent magnet can be corrected, and an excellent beam spot can be obtained.
JP7226681A 1981-05-15 1981-05-15 Magnetic focusing crt unit Granted JPS57187843A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP7226681A JPS57187843A (en) 1981-05-15 1981-05-15 Magnetic focusing crt unit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP7226681A JPS57187843A (en) 1981-05-15 1981-05-15 Magnetic focusing crt unit

Publications (2)

Publication Number Publication Date
JPS57187843A true JPS57187843A (en) 1982-11-18
JPH0316732B2 JPH0316732B2 (en) 1991-03-06

Family

ID=13484303

Family Applications (1)

Application Number Title Priority Date Filing Date
JP7226681A Granted JPS57187843A (en) 1981-05-15 1981-05-15 Magnetic focusing crt unit

Country Status (1)

Country Link
JP (1) JPS57187843A (en)

Also Published As

Publication number Publication date
JPH0316732B2 (en) 1991-03-06

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