| 摘要 |
PURPOSE:To obtain an inexpensive electroagnetic focusing type cathode-ray tube offering a beam spot being truly round and excellent satic convergence, the cathode-ray tube being readily assembled with high accuracy, by a method wherein a sectional external shape at a right angle to the tube axis of a yoke is made non-circuilar in order to allow the yoke to be supported by an electrode-upporting rod commonly used for other electrodes, and the shape of a permanent magnet, the length of a gap between the yokes, the lenght of the yoke in the direction of its tube axis are set at values within the range of satisfying particular correlation. CONSTITUTION:What is greatly different from the convertional example is that the external shapes of yokes 51a, 51b and a gap electrode are flat, the yoke and the gap electrode 14a being supported by an electrode-supporting rod 9a commonly used for other electrodes by utilizing a gap between the flat portion and the inside wall surface of a nexk tube. As a permanent magnet, taking it into consideration that the magnet is used for a television for household use, the one made of ferrite will be most suitable in view of its performance vs. cost ratio. Moreover, by defining the shape of the permanent magnet having outside and inside diameters Fo, phii and t in thickness as 1.7<=phio/phii<=23, 0.35<=t/phii<=0.65, it becomes possible to obtain such a cathode-ray tube free from a shear in color, distortion in the shape of a beam spot, and the one which is readily assembled with high accuracy. |
