| 摘要 |
PURPOSE:To prevent any inverted magnetization of the part between the magnetic poles of a magnet, which is installed in the neck part of a color picture tube, by subjecting the magnetic poles to saturation magnetization by means of a d. c. magnetic field after they are demagnetized, demagnetizing the part between the magnetic poles by means of a damping alternating magnetic field, magnetizing the magnetic poles to a given extent by means of a d. c. magnetic field, and demagnetizing the part between the magnetic poles by means of a damping alternating magnetic field. CONSTITUTION:An electron gun 23 is installed in a neck part 22 of a color picture tube 21, and an annular magnet 24 is provided at a given position of the gun 23. At the same time. the magnet 24 is magnetized with a magnetizer 26 from its outside. The magnetizing method for the magnet 24 includes the first stage of completely demagnetizing the magnet 24 by means of a damping alternating magnetic field having a sufficiently intense initial value, the next stage of subjecting the part where magnetic poles are formed by a first d. c. magnetic field 42 to saturation magnetization, and the following stage of demagnetizing only a non-saturatedly magnetized part between the magnetic poles by means of a damping alternating magnetic field 43. Next, the magnetic poles are demagnetized to a specified extent by applying a second d. c. magnetic field 44, which is smaller than the first d. c. magnetic field 42 and the direction of which is opposite to that of the field 42. After that, demagnetization is carried out across the magnetic poles by means of a damping alternating magnetic field 45. By the means mentioned above, any inverted magnetization between the magnetic poles can be prevented, and the accuracy of the magnetization is increased. |
