| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain a piezoelectric actuator which can prevent the generation of cracks caused by the use of the piezoelectric actuator, and is high in durability and reliability. <P>SOLUTION: Grooves 20 are formed on the electrode surface 14 of a piezoelectric element 11. The grooves 20 are formed in the longitudinal direction of the electrode surface 14, that is, all over the expansion and contraction direction of the piezoelectric element 11. In other words, the grooves 20 are certainly formed on a cross section with respect to the width direction of the electrode surface 14. The width of each groove 20 is shorter than a gap between the adjacent grooves 20. The depth of each groove 20 is deeper than a half of the thickness of the piezoelectric element 11, but does become the same as the thickness of the piezoelectric element 11. When cracks are generated on the surface of the piezoelectric element 11 depending on use, cracks are generated in the piezoelectric element 11 by the further application of vibration. However since the grooves 20 are certainly formed in the width direction of the electrode surface 14, the cracks generated in the width direction of the electrode surface 14 certainly reach the grooves 20. When the cracks reach the grooves 20, the cracks do not progress any more, and the piezoelectric element 11 is not broken. <P>COPYRIGHT: (C)2008,JPO&INPIT |
