JPS57187843A - Magnetic focusing crt unit - Google Patents
Magnetic focusing crt unitInfo
- 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
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.
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) |
-
1981
- 1981-05-15 JP JP7226681A patent/JPS57187843A/en active Granted
Also Published As
Publication number | Publication date |
---|---|
JPH0316732B2 (en) | 1991-03-06 |
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