Patent ID: 7624639

Claim:
An acceleration sensor comprising: a detection element; and retaining members retaining an end portion of the detection element in a longitudinal direction thereof at two principal surfaces of the end portion, the detection element including a plurality of piezoelectric ceramic layers laminated together; wherein the detection element includes at least one interlayer electrode interposed between the plurality of piezoelectric ceramic layers and principal-surface electrodes disposed on the principal surfaces; the acceleration sensor obtains at least one of a voltage and a charge from the principal-surface electrodes and the interlayer electrode, the at least one of the voltage and the charge being generated in the detection element in response to an application of acceleration; the principal-surface electrodes and the interlayer electrode that is not electrically connected to the principal-surface electrodes extend into a retaining area in which the detection element is retained by the retaining members; the retaining members include extraction electrodes on inner surfaces thereof; at least a portion of each principal-surface electrode extending into the retaining area of the retaining members and at least a portion of the extraction electrode on the inner surface of the corresponding retaining member face each other and are electrically connected to each other; and within the retaining area in which the detection element is retained by the retaining members, the piezoelectric ceramic layers are not polarized in areas between the principal-surface electrodes and the interlayer electrode that is not electrically connected to the principal-surface electrodes.