| 摘要 |
PROBLEM TO BE SOLVED: To provide a display which is free of occurrence of focus deterioration in the high luminance part of a CRT screen. SOLUTION: The display that has a CRT (20) provided with an electron gun, having focus electrodes (23 and 24) to which dynamic focus voltage is applied for focusing electrons to be drawn from a cathode (25) and a dynamic focus circuit (40) for generating dynamic focus voltage by superimposing AC voltage, having a waveform vary in synchronization with the deflection in a horizontal direction and the deflection in a vertical direction of electronic beams proceeding toward a fluorescent surface on the anode side of the CRT to DC current to be supplied, is provided with correction means (41, 42 and 43) for lowering the DC voltage to be supplied to the circuit (40) by a prescribed value, while the luminance signal level showing the luminance of the CRT screen is in a state of exceeding a threshold.
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