| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a piezoelectric actuator having superior durability in which the amount of displacement of bending distortion in a thickness direction is not deteriorated significantly in a piezoelectric ceramic layer with time, even driving with a driving method in which a voltage is applied in reverse direction exceeding an electric field resistivity strength Ec. <P>SOLUTION: In the piezoelectric actuator, a ratio of piezoelectric displacement component ε<SP>P31</SP>is set at 0.6 or above to a total amount of displacement represented by a formula (1): ε= ε<SP>P31</SP>+ε<SP>d31</SP>(1) (in the formula, ε<SP>P31</SP>shows the piezoelectric displacement component out of the amount of displacement, ε<SP>d31</SP>shows a 90° rotation displacement component out of the amount of displacement) when applying the voltage exceeding 1.2 times the electric field resistivity strength Ec of the piezoelectric ceramic layer to a piezoelectric ceramic layer. The average grain diameter of a piezoelectric ceramics forming the piezoelectric ceramic layer is desirably 0.5-2.5 μm. <P>COPYRIGHT: (C)2007,JPO&INPIT |
