Patent ID: 7353707

Claim:
An acceleration sensor comprising: a base plate; and first and second resonators each including a piezoelectric material and each having electrodes on two opposite main surfaces thereof, each of the first and second resonators having a vibrating section at an intermediate portion of the respective resonator with respect to a longitudinal direction thereof; wherein the first and second resonators are attached to opposite sides of the base plate with respect to a direction in which acceleration is applied so as to define a bimorph acceleration-sensor element, at least one longitudinal end of the acceleration-sensor element is fixed such that the first and second resonators bend in the same direction in response to the acceleration, and changes in frequency or changes in impedance in the first and second resonators caused by the bending of the acceleration-sensor element are differentially detected in order to detect the acceleration; opposite sides of the acceleration-sensor element with respect to the application direction of acceleration are respectively covered with a pair of casing components; and the first and second resonators are attached to the base plate such that the electrodes of the first and second resonators face at least one of opposite open planes defined by a combination of the acceleration-sensor element and the casing components with respect to a direction that is substantially perpendicular to the application direction of acceleration.