| 摘要 |
PURPOSE:To perform the correction with high precision and a wide range by arranging a predetermined number of magnetic pole pieces beforehand on a deflection yoke or at predetermined positions nearby, detecting the miss-convergence on a phosphor screen, and energizing necessary magnetic pieces to the necessary strength from the outside. CONSTITUTION:A picture tube 1 is composed of a panel 2 formed with a phosphor screen 3 inside, a neck 6 housing an electron beam 5, and a funnel 4 connecting the panel 2 and the neck 6. A color purity correction magnet 7A and static convergence magnets 7B, 7C are provided on the outside of the neck 6, and a deflection yoke 9 is coupled outside the cone section 8 of the funnel 4. Storage ribs 11 are provided at a uniform distance at eight positions, for example, along the outer periphery of the york 9, and an unenergized magnetic piece 10 is stored in each rib 11. An optional picture tube 1 and a york 9 are combined together, the miss-convergence on the phosphor screen 3 is detected with a sensor, and necessary ones among the magnetic pieces stored in the ribs 11 are energized to the necessary strength. |
