| 摘要 |
PROBLEM TO BE SOLVED: To automatically end discharges when electric discharge occurs between an electrode of an electron gun and an anode or a cathode, in a display device comprising a CRT having such a type of an electron gun as a voltage is applied thereto by a voltage source dedicated to the electron beam control and an electrode current is supplied thereto. SOLUTION: A comparison circuit 19 compares a voltage of a high level feedback point 9 with an output voltage of a Gm electrode voltage source 17, and when electric discharge occurs between the electrode of the electron gun and the anode or the cathode and the comparison circuit detects that only the feedback voltage has dropped lower than a steady-state value, the circuit supplies a detection signal to a high voltage circuit 22. Receiving the detection signal, the high voltage control circuit 22 decreases the voltage of a high voltage line 5, and controls to decrease the voltages to be applied to the anode and G3 electrode, respectively. |
