Piezoelectric properties in (Pb, Me) ((Co1/2W1/2), Ti)O3 ceramics (Me=Ba, Sr or Ca) containing small amounts of MnO and NiO have been investigated. These ceramics are characterized by high apparent density, small dielectric constant (about 200) and facility in poling procedure. Among the ceramics added with the alkaline earth metals, the Ca-modified ceramics show markedly excellent performance–large longitudinal coupling factors k 33=0.54, k t=0.52, small transverse coupling factors k 31=0.027, K p=0.043 and small temperature coefficients less than 5 ppm/°C of frequency constants for radial and thickness vibration modes.

In order to improve displacing devices, new methods for supporting a bimorph element with a double-support structure were investigated. Consideration of bending properties revealed that, when the bimorph element was bent, the cross-sections at both of the bimorph element's ends rotated. A double-support bimorph element with U-shaped metal plates at each end was designed, the result being used. It was found that the displacement for the double-support bimorph with U-shaped metal plates was approximately 4 times larger than the displacement for a conventional double-support bimorph.