Patent ID: 8413510

Claim:
An acceleration sensor comprising: a substrate; a flexible section having flexibility and coupled to the substrate; a weight coupled to the substrate via the flexible section, wherein the weight has a first main surface and the substrate has a second main surface; and a first opposed electrode unit including a first electrode placed on the first main surface of the weight, a second electrode placed on the second main surface of the substrate and spaced away from and facing the first electrode, the first electrode and the second electrode providing a first capacitance between the first electrode and the second electrode; a second opposed electrode unit including a third electrode placed on the first main surface of the weight, a fourth electrode placed on the second main surface of the substrate and spaced away from and facing the third electrode, the third electrode and the fourth electrode providing a second capacitance between the third electrode and the fourth electrode, wherein the first electrode and the third electrode are arranged along a first direction, the second electrode and the fourth electrode are spaced away from and face the first electrode and the third electrode along a second direction perpendicular to the first direction, respectively; a processor adapted to detect a component of an acceleration along the first direction applied to an object based on the first capacitance and the second capacitance, apply a control voltage to the first opposed electrode unit and the second opposed electrode unit, and change the control voltage when both of the first capacitance and the second capacitance simultaneously increase or simultaneously decrease.