JPS6448043A - Temperature control method for liquid crystal optical device - Google Patents

Abstract

PURPOSE:To enable the temp. control in which the influence on the life of a liquid crystal element arising from driving of heaters is eliminated by maintaining the phases of the respective waveforms to be impressed to the heater electrodes and signal electrodes in a liquid crystal element in a prescribed relation. CONSTITUTION:A liquid crystal light valve has a liquid crystal panel 1, a polarizing plate 2, and a substrate 3 packaged with a liquid crystal driving circuit and a temp. control circuit. The heater electrodes 6, 10 are provided on both sides of a scanning electrode 5 of the scanning electrode substrate 4 of the panel 1. Both ends thereof are so positioned as not to face a signal electrode substrate 7. A thermistor 8 for temp. detection is mounted to the electrode 6. The waveform of the inphase or antiphase of the phase of one of the two signals to be impressed to the signal electrodes is kept impressed at all times to one of both the terminals of the electrodes 6, 10 and the waveform of the antiphase of one terminal is impressed to the other terminal at the time of conducting the electrodes 6, 10 and the waveform of the inphase of the one terminal is impressed thereto at the time of non-conducting the electrodes 6, 10. As a result, the DC component of the voltage to be impressed to the liquid crystal is kept zero at all times in any shutter position.