| 摘要 |
PURPOSE:To make a centering permanent magnet unnecessary by disposing more than two annular focusing permanent magnets one above the other in a way that each circularly reciprocates and by shifting the center of magnetic field distribution of the permanent magnet from a geometrical center. CONSTITUTION:At least 2 pieces of first and second annular focusing permanent magnets Md1 and Md2, which are magnetized in a thickness direction, are disposed at a tabular axis O-O' of a cathode ray tube tabular body 1 in a way that both of which may circularly reciprocate around the tabular axis. At least one of the magnets Md1 and Md2 is magnetized with the center of magnetic field distribution relative to a surface perpendicularly interseting with an axial centr is shifted radially from a geometrical center of the magnet. At this time, the two magnets Md1 and Md2 can from original magnetic focusing lens and at the same time an upper radial directional magnetic field is generated at the axis center to enable electronic beam centering and a centering magnet becomes unnecessary. |
