| 摘要 |
PURPOSE:To cancel completely a change in vertical deflection sensitivity due to one vertical focusing electrode by the other and to attain a control of only brightness by disposing two prepared vertical focusing electrodes so as to approach each other and impressing a control voltage from a vertical focusing electrode drive circuit to either one of said vertical focusing electrodes. CONSTITUTION:An electrode 3 is constituted such a way that two electrodes 3a and 3b approach each other. With this constitution, when the voltage of the electrode 3a rises, vertical deflection sensitivity drops. When the voltage of the electrode 3b rises, its vertical deflection sensitivity rises and a brightness change is small. Moreover, since the electrodes 3a and 3b approach, a voltage is given to the electrode 3b through a resistance R1, and a capacitor C1 is inserted between the electrode 3b and GND. Then a waveform similar to the AC component of a voltage waveform impressed to the electrode 3a from a vertical focusing electrode drive circuit is impressed to the electrode 3b, and a change in vertical deflection sensitivity due to the electrode 3a can be completely canceled by the electrode 3b.
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