Patent ID: 8148876

Claim:
A piezoelectric actuator comprising: a piezoelectric element that performs an expansion and contraction movement in accordance with the state of an electrical field, a base having said piezoelectric element adhered to at least one surface thereof, and a support member that supports said piezoelectric element and said base; wherein said base is connected to said support member by way of a vibration film, the outline shapes of said piezoelectric element and said support member differ from each other in that said piezoelectric element has a different size than said support member and that said piezoelectric element has a different shape than said support member, and said piezoelectric element and said base vibrate in the direction of thickness of said piezoelectric element in accordance with said movement of said piezoelectric element, wherein, when a 1 is the length in the minor-axis direction and b 1 is the length in the major-axis direction in the outline shape of said piezoelectric element, a 1 /b 1 is in the range from 0.6 to 1.