PURPOSE: To increase transmitted light energy by providing an opening signal and a maintaining signal within a write allotted time and a closing signal within a time other than said allotted time.

CONSTITUTION: A glass substrate having four pieces of write selection electrodes and a glass substrate having M pieces of data signal electrodes are opposed to oppose and cross each other; and a nematic liquid crystal composition is enclosed between both substrates and a couple of polarizing plates are provided outside of them. Then, a signal is applied between a write selection electrode and a data signal electrode to perform four-time-division driving. In this case, the valve opening signal 903 and maintaining signal 902 are provided within the write allotted time and the closing signal 901 is provided within the time other than said allotted time to transmit more light energy a liquid crystal light valve than when both opening and closing signals are provided within the time.