To always obtain a fixed light quantity by preventing as much as possible a change of a transmission light quantity at a continuous drive time or accompanied with a temp. change in an optical modulator consisting of material having an electrooptical effect.
This method is a drive method for the optical modulator on/off controlling a beam by applying a voltage to an optical shutter element consisting of the material having the electrooptical effect, and at least two kinds of different pulse voltages except a half wavelength voltage are applied to the optical shutter element for one modulation period, e.g. for a scan period of 1 line. That is, the pulse voltages of voltage values Vb, Vc different from the half wavelength voltage are applied successively, and the pulse voltages of different polarity of the same absolute value are applied successively.
SAITO ITARU
HIROMOTO YASUYUKI
