| 摘要 |
PURPOSE:To attain the reproduction of a white level with good quality by changing the potential distribution around the cathode and increasing an electron beam incident to a fluorescent body only when the luminance level of a video signal approaches a white peak. CONSTITUTION:A pulse inputted to an input terminal 49 is inputted to a base of a transistor (TR)50 in differential pairs with a TR46. In setting a base voltage Vr of the TR46 to a midpoint between a high level and a low level of an input pulse 6H to the input terminal 49, the TR50 is turned off at a period of a low level of the 6H pulse and the voltage of a power input terminal 43 is charged into a lower voltage VH. Since the TR50 is turned on during the high level period of the 6H pulse and a current I1 flows, the base voltage of a TR53 is lowered by the voltage drop's share and the voltage at an output terminal 44 is decreased. When the luminance level is higher, the voltage is increased to the voltage VH, the luminance is increased at the white peak point.
|
