| 摘要 |
PURPOSE:To lower the least brightness of a display and to improve the display contrast rate by providing a minute display control device to ON-control a minute display circuit only for a specific time before the starting of the brightness control. CONSTITUTION:The brightness control is carried out by inputting a brightness data output simultaneously with a scanning signal Vc from a display control circuit 10, and using the output of a PWM circuit 11 to control the time width. And a minute display control device is composed of timers 20 and 21, a high voltage switch circuit 22, and the like. When the scanning signal Vc is output, a delay time T1 is produced by the timer 20, and a delay time T2 is produced by the timer 21 immediately after the delay time T1. During the delay time T2, the switch element 22a of a high voltage switch circuit 22 is turned on, and a lamp 1 is to carry out a minute discharge through a resistance 4. As a result, the brightness level in a black time when the main discharge current does not flow is to be reduced, and the contrast rate is improved extensively. |
