Synthesis of PLZT adjusted in composition to the application for optical microgates

After optical microgates made of PLZT ceramics are driven for a long time, the light intensity transmitted through the gates decreases, and a large leakage of light appears along one of the electrodes when the applied voltage is removed. The reason for this phenomenon has been experimentally confirmed to be the space charge occurring under the coexistence of an electric field and light. The phenomenon is strongly affected by atmospheres in hot isostatic pressing in the sintering process. Eliminating this phenomenon, optimum processing conditions to manufacture PLZT for optical applications have been established. The optical microgates made of the PLZT modified in composition are stable so that a change of the light intensity due to the lapse of time is slight. Therefore, they are suitable for the applications for optical recording heads for high speed electrophotographic printers and full-color printers using silver halide photography.