| 摘要 |
A liquid crystal device using a simple matrix panel which is driven by seven level potentials including PV3, PV2, PV1, VC, MV1, MV2, and MV3 in 4-line simultaneous selection driving at a high duty n1. The bias ratio c1 at this time is (PV2-VC)/L/PV3. In 4-line simultaneous selection driving at a low duty n2, the liquid crystal device is driven by five levels including PV2, PV1, VC, MV1, and MV2 by stopping the operation of third and fourth voltage raising circuits (230) and (232). The bias ratio c2 at this time is (PV2-VC)/L/PV2. When changing the duty, the relation n1.c1<2>=n2.c2<2 >is satisfied. This eliminates the need for contrast adjustment each time the duty is changed. A voltage-raising multiplying factor "k" in a third voltage raising circuit (230) satisfies the relation k=PV3/PV2. Therefore, n2=n1.(c1/c2)<2>=n1.(1/k)<2 >is realized.
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