| 摘要 |
In a cathode-ray tube, a nonmetallic material such as ceramic or the like is used for an electrode 1a part of an electron gun. Consequently, the deterioration of the efficiency of modulation of electron beam trajectories by an eddy current generated at the metallic electrode part of the electron gun in the high-frequency magnetic fields and the heat generation at the electrode can be decreased. The generation of the eddy current by high-frequency magnetic fields by a convergence yoke or the like can be restrained by using a nonmetallic material for the electrode part of the electron gun. Consequently, the efficiency of modulation of electron beam trajectories is not deteriorated also in a high-frequency modulation zone and the heat generation at the electrode part can be also restrained. Less deterioration of efficiency of modulation of electron beam trajectories by the alternating magnetic fields occurs even in the high-frequency modulation zone, for example, more than 100kHz. Therefore, an excessive power is not required in a deflecting yoke, a convergence yoke, a velocity modulation coil or the like, even in a cathode-ray tube that modulates electron beam trajectories at high frequency in a high definition television or the like. As a result, the damage to a neck portion of a cathode-ray tube caused by heat generation at the electrode part also can be prevented.
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