| 摘要 |
PURPOSE:To prevent the quality deterioration of the display picture caused by the lack or unevenness of the holding time of the voltage applied to the electrode of the liquid crystal display substance by setting the scanning frequency according to the time constant of each picture element in the liquid crystal display substance. CONSTITUTION:The video signal drawn out at video detection circuit 401 undergoes A/D conversion 402 and then memorized temporarily in auxiliary memory circuit 403. This memory contents is conveyed to main memory circuit 406 within the blanking time of each scanning line. Circuit 406 always holds the data equivalent to one frame of the picture, and this data is read out by multiplexer 409 and circuit 408 which generates the timing signal deciding the scanning velocity to be given D/A donversion 409 and then to be returned to the original video signal. The D/A-converted video signal is sent to analog multiplexer 410 for sequential scanning of each column. In such constitution, the scanning velocity is eliminated for liquid crystal display panel 412, and accordingly the next scanning is carried out before the charge stored in the capacity between electrodes of the capacitor of each picture element and the liquid crystal panel gets away. Thus, the sufficiently high quality can be kept for the display picture. |
