Patent ID: 6810740
Filing Date: 2004-11-02
Classification: G01P

Abstract:
An acceleration sensor comprising:a piezoelectric element; and a support member for supporting the piezoelectric element at both longitudinal ends thereof; wherein the piezoelectric element includes a laminate having at least three piezoelectric layers; an intermediate piezoelectric layer of the at least three piezoelectric layers is a dummy layer which generates no charge when acceleration is applied thereto; each of two outer piezoelectric layers of the at least three piezoelectric layers includes at least four longitudinally aligned regions defining cells which are separated at two borders and one central border where stress is inverted when the acceleration is applied; the two outer piezoelectric layers are polarized in the direction of thickness of the piezoelectric element such that the cells which are adjacent to each other in a longitudinal direction of the laminate have opposite polarization directions and such that cells which are aligned with each other in the direction of thickness of the laminate are polarized in the same polarization direction; electrodes are arranged on the top and bottom major surfaces of the piezoelectric element and between the piezoelectric layers such that a first pair of the cells located on one side of the central border are connected in parallel, and a second pair of the cells located on the other side of the central border are connected in parallel in each of the two outer piezoelectric layers, and such that the first pair of parallel-connected cells on the one side are connected in series to the second pair of parallel-connected cells on the other side; and at least one of the electrodes on each of the top and bottom major surfaces and between the layers extend to different end surfaces in the longitudinal direction of the piezoelectric element.