| 摘要 |
PURPOSE:To avoid the bad influence of the earth magnetism on image quality by shielding the unnecessary magnetic field near the electron gun by installing a rear shield with high permeability extending in the back of the deflection york coaxially with the axis of the cathode. CONSTITUTION:A cylindrical rear shield 12 made of a material with high permeability such as permalloy has an expanded front opening 12a located close to the rear end of a deflection york 8. The rear end 12b of the rear shield 12 located in the back of a magnetic assembly 11 has a small diameter. Due to the rear shield 12, the magnetic flux lines from the rear of the deflection york 8 flows into the shield 12 without migrating into a neck 3. Consequently, unnecessary magnetic flux lines extending along the axis of a cathode-ray tube 7 are remarkably shielded near an electron gun 13. |
