| 摘要 |
PURPOSE:To maintain dependency on pulse width and to control quantity of transmitted light as desired by preventing continuous impression of the voltage pulses for selecting on and off of a liquid crystal element in the same polarity direction within at least a non-selection period. CONSTITUTION:The pulse voltages V2.t13 and (V2-V4)t12 above the saturation value are applied to the element in order to turn the element on in the selection period t10 and off in t20 and to unify the arranging directions of the liquid crystal in one direction. The voltage (V1-V4)t1 of a reverse polarity and above the saturation value is then applied thereto when the element is on and (V1-V3)t14 below the threshold of the liquid crystal is applied thereto when the element is off. The 3rd voltage pulse is applied to the element in the selec tion period t15(t25) to prevent the continuous impression of the pulses of the same polarity or the continuous impression thereof via 0 in the beginning of the period t10 as well as t20, t11, t21. The voltage pulses for unifying the liquid crystal arrangement can be placed in the arbitrary position of the non-selection period, by which the free control of the quantity It16 of the transmitted light is permitted and the good optical response is obtd.
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