| 摘要 |
PURPOSE:To simplify a power source circuit by supplying a necessary pulse train to common electrodes and segment electrodes, respectively, which are opposed by inserting a liquid crystal between them and constitute two liquid crystal display elements, respectively. CONSTITUTION:Common electrodes C1-C3 and segment electrodes S1-S4 constitute two liquid crystal elements, respectively. A first pulse train E1 of a driving pulse of pulse width (t) and a high frequency pulse of the same voltage as that of a driving pulse generated during the time (t) before or after said pulse, and a second pulse train E2 which has inverted a level of the pulse train E1 are supplied to the electrode C1. To the other electrode C2, a pulse train whose phase is shifted by the time (t) from the electrode C1 is supplied. On the other hand, pulse trains P3-P6 which consist of a pulse train the same in voltage as that of driving pulses of the electrodes C1, C2, a period of the time 4t and a duty of 1/2, and whose phases are shifted by 1/4 period each are supplied selectively to the electrodes S1-S4. By using this same voltage, a voltage raising circuit and a voltage lowering circuit become unnecessary, and the constitution of a power source circuit is simplified. Also, an external capacitor is also unnecessary, and a chip area of an integrated circuit becomes small.
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