| 摘要 |
PROBLEM TO BE SOLVED: To reduce a picture degradation at the begining when a power source SW is turned ON by allowing an anode voltage to be cut by being delayed by a fixed time as compared with a cathode voltage when the power source SW is cut. SOLUTION: When the power source SW is changed over from ON to OFF in a timing T1, an anode voltage is lowered to 0 voltage after its driving voltage VA is maintained till a timing T4. Voltages of a signal voltage and a drawer electrode voltage and a wire cathode electrode voltage are respectively lowered to 0 voltage from its driving voltage VG4, its driving voltage VG3 and its driving voltage VK in the timing T1. The temp. of the wire cathode which was a cathode heating temp. TK till the timing T1 is lowered to a room temperature TR by spending a time till a timing T3. When the power source SW is cut by the previous timings, since the anode voltage is cut by being delayed by the fixed time as compared with the wire cathode voltage, electron beams passed through an electrode unit after the timing T1 are absorbed with anode. |
