A static induction vibration power generating device has been already proposed, in which electric charges are provided to one electrode of a variable capacitance, the electrode charges are induced to the opposed electrode by a static induction, a change in the induced electric charges is brought about by a change in capacitance, and the change in the electric charges is extracted as electrical energy (refer to, for example, Patent document 1).
FIG. 7 shows a static induction vibration power generator described in the aforementioned Patent document 1. FIG. 7 is a schematic cross-sectional view of a vibration power generator 10 using an electret.
The vibration power generator 10 is composed of a first substrate 11 having a plurality of conductive surface regions 13 and a second substrate 16 having a plurality of electret material regions 15. The first substrate 11 and the second substrate 16 are disposed so as to have a predetermined clearance each other. The second substrate including the electret material regions 15 is fixed. The first substrate 11 having the conductive surface regions 13 is coupled to a fixation structure 17 through springs 19. The springs 19 are connected to the both side surfaces of the first substrate 11, and also connected to the fixation structure 17. The first substrate 11 is capable of returning to its home position due to the springs 19, or the first substrate makes a lateral motion (for example, an X-axial motion) to be capable of returning to the home position. This movement brings about increase and decrease of the overlapping area between the electret material regions 15 and the opposed conductive surface regions 13, which results in a change of electric charges in the conductive surface regions 13. A static induction vibration power generator performs electrical generation by extracting the change of electric charges as electrical energy.
Patent document 2 discloses an electrostatic acting device using a static induction vibration power generator. An example of the electrostatic acting device is shown in Patent document 2. As shown in FIG. 8, this device 41 is composed of:                a vibration power generator composed of a first electrode section 20 including a plurality of movable electrodes 22a and 22b, a second electrode section 30 including an electret film 32 and a first dielectric layer 34 formed on the film 32 and a first insulating film 33 provided between the first dielectric layer 34 and the electret film 32,        bridge rectifier circuits 42a, 42b respectively connected to the plurality of electrodes 22a, 22b,         DC converters 43a, 43b connected to the bridge rectifier circuits, and        a load 40.        
The bridge rectifier circuits rectify AC voltages output from the respective movable electrodes 22 and convert the AC voltages into a DC voltage. The converted DC voltage is converted by a DC-DC converter and then output to the load.
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