NEW APPLICATIONS OF PHOTOSTRICTIVE FERROICS

Photostriction in ferroelectrics arises from a superposition of photov oltaic and inverse piezoelectric effects. (Pb,La)(Zr,Ti)O-3 ceramics d oped with WO3 exhibit large photostriction under irradiation of near-u ltraviolet light, and are applicable to remote control actuators and p hotoacoustic devices. Using a bimorph configuration, a photo-driven re lay and a micro walking device have been developed, which are designed to start moving as a result from the irradiation, having neither elec tric lead wires nor electric circuits. The mechanical resonance of the bimorph was also induced by an intermittent illumination of purple-co lor light; this verified the feasibility of applying photostriction fo r ''photophone'' applications.