Vibrational Energy Harvester Element

Abstract

A vibrational energy harvester element includes: a first electrode; a second electrode that moves in a predetermined direction with respect to the first electrode; a third electrode; a fourth electrode that moves in the predetermined direction with respect to the third electrode; and a support portion that supports the second electrode and the fourth electrode so that they are movable along the predetermined direction; and wherein: the first electrode and the third electrode are disposed along the predetermined direction; at least one of facing surfaces of the first electrode and the second electrode, and at least one of facing surfaces of the third electrode and the fourth electrode, are electrically charged; and the support portion supports the second electrode and the fourth electrode in a state in which electrostatic force between the first electrode and the second electrode, and electrostatic force between the third electrode and the fourth electrode are balanced along the predetermined direction.

1 . A vibrational energy harvester element, comprising:
 a first electrode;   a second electrode that moves in a predetermined direction with respect to the first electrode;   a third electrode;   a fourth electrode that moves in the predetermined direction with respect to the third electrode; and   an elastic support portion that supports the second electrode and the forth electrode so that they are movable along the predetermined direction;   and wherein:   the first electrode and the third electrode are disposed along the predetermined direction;   at least one of facing surfaces of the first electrode and the second electrode, and at least one of facing surfaces of the third electrode and the forth electrode, are electrically charged by a predetermined charged voltage, which causes the elastic support portion to support the second electrode and the forth electrode in a state in which electrostatic force between the first electrode and the second electrode, and electrostatic force between the third electrode and the forth electrode are balanced along the predetermined direction; and   the predetermined charged voltage causes a vibration center position by movement of the second electrode and the fourth electrode to be positioned at a point where the elastic support portion stabilizes.   
     
     
         2 . The vibrational energy harvester element according to  claim 1 , wherein,
 support rigidity along the predetermined direction is lower than support rigidity along direction different from the predetermined direction, among support rigidities with which the elastic support portion supports the second electrode and the forth electrode.   
     
     
         3 . The vibrational energy harvester element according to  claim 1 , further comprising
 a load that is connected to the first electrode and to the third electrode, and wherein the load is driven by electrical power obtained from power generation due to change of electrostatic capacitance caused by relative displacement between the first electrode and the second electrode, and from power generation due to change of electrostatic capacitance caused by relative displacement between the third electrode and the forth electrode.   
     
     
         4 . The vibrational energy harvester element according to  claim 1 , comprising a plurality of elastic support portions which extend from a base to the second and fourth electrodes in a second direction and wherein the plurality of elastic support portions are arranged at different positions along a direction perpendicular to the predetermined direction and the second direction.