| 摘要 |
PURPOSE:To reduce the deterioration in magnetism of a field controller owing to the high frequency of the horizontal deflection frequency, and prevent the decrease of convergence quality, by composing the field controller, of a material of a good magnetic high frequency property. CONSTITUTION:In a convergence electrode 7, are fixed and arranged ring-form first field controllers 8a and 8b at the peripheries of the outer beam passage holes 7A and 7C, and disk-form second field controllers 9a and 9b at the upper and the lower sides of a central beam passage hole 7B respectively. These field controllers 8a, 8b, and 9a, 9b are formed of a material of a good magnetic high frequency property with little hysteresis loss, little eddy-current loss, and little magnetic after-effect, such as a material with specific permeability 3,000 or more, and little maintaining capacity less than 0.025, for example. Therefore, the magnetic property to the horizontal deflection frequency of field controller can be improved. As a result, the variation amount of the convergence is made smaller, and the quality of convergence can be improved.
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