ABSTRACT
When ultraviolet light with wavelength around 365 nm illuminates a PLZT element as illustrated in Fig.l(a), the PLZT element stretches its height H in the polarizing direction and contracts in the direction normal to that, namely, the width W , as superposition of photoelectric and piezoelectric effects[!]. We adopted the bimorph structure to get a large displacement, as shown in Fig.l(b), which adhered two identical PLZT elements so as to reverse their polarizing directions. In this case, electrode plates of these two elements constitute common plates on the two faces of each element. Now, when the left end of this optical actuator is fixed and the upper PLZT element is illuminated by ultraviolet light as illustrated in Fig.l (b), a high photovoltage is produced between the common electrodes due to the photoelectric effect, and contraction of the width W of the upper element is caused. On the other hand, because the lower PLZT element is adhered in opposite to the polarizing direction of the upper element, the height H contracts and the width W stretches on the lower element due to the above-mentioned photovoltage. Accordingly, the right end of this optical actuator is led to bend upward. When ultraviolet light illuminates the surface of the lower element in contrast, the actuator bends downward through the process opposite to the above.
