| 摘要 |
PURPOSE:To automatically adjust a display contrast freely by changing an electric charge value of a color pulse through a drive electric charge control circuit according to an instruction for color concentration. CONSTITUTION:If a color concentration is instructed through a switch for a color concentration instruction circuit 60, AND gates 48a-48c to which a drive electric charge control circuit 46 corresponds are opened. From these gates 48a-48c, a 60-second pulse of one second width at 0.5Hz from a divided-by-60 counter 16 for a clock circuit 14 and a 60-second pulse whose electric charge value is changed by a pulse width such as 750 milli seconds, 500 milli seconds, etc. through the intermediary of AND gate 52 controlled by 1Hz and 2Hz frequency-divided outputs and AND gate 56 controlled by 1Hz frequency divided output, are output to drive a shared electrode 32 for an electrochromic display device 26. Consequently, a display contrast is freely adjusted according to a color concentration instruction. |
