JP7156649B2 - Vibration power generation element and vibration power generation device - Google Patents

Description

The present invention relates to a vibration power generation element and a vibration power generation device.

As one of the energy harvesting technologies for harvesting energy from environmental vibrations, ME
A method of generating power from environmental vibrations using a vibration power generating element, which is an MS (Micro Electro Mechanical Systems) vibration element, is known. The vibration power generating element itself includes a piezoelectric element or an electrostatic capacitance type element, and is an element that generates AC power equal to the frequency of the environmental vibration when vibrated at the frequency of the environmental vibration. An electrostatic induction vibration power generation element generates power by induced charges generated by mutually vibrating a plurality of electrodes (see, for example, Patent Document 1).

JP 2014-228283 A

Since the vibrational energy of environmental vibrations is weak, there is a demand for a vibration power generation element that converts environmental vibrations into electrical energy with high efficiency.

A vibration power generation device according to a first aspect of the present invention is a vibration power generation device that outputs alternating current power from an output line by vibration from the outside , wherein the intermediate electrode does not have an electret and is not connected to the output line; A plurality of electret electrodes arranged to face an intermediate electrode and having electrets on at least part of a surface facing the intermediate electrode; and a charge injector for injecting charges having characteristics opposite to characteristics of electrets formed on surfaces of the plurality of electret electrodes into the intermediate electrode.
A vibration power generation device according to a second aspect of the present invention includes the vibration power generation element vibration power generation element according to the first aspect, and a power supply device.

ADVANTAGE OF THE INVENTION According to this invention, the energy of an environmental vibration can be converted into an electrical energy with high efficiency.

1 is a diagram showing a configuration of a vibration power generation device 10 according to an embodiment of the present invention and a vibration power generation device 100 including the vibration power generation device 10. FIG. 4A and 4B are views for explaining the principle of operation of the vibration power generation element 10 of the embodiment; FIG. 2A to 2C are diagrams showing charges induced in the electret electrode 11 and the intermediate electrode 12 at respective relative positions of the intermediate electrode 12 with respect to the electret electrode 11. FIG. FIG. 4 is a diagram for explaining one mode of operation when an intermediate electrode 12 is neutralized; 3A to 3C are diagrams showing charges induced in the electret electrode 11 and the intermediate electrode 12 at respective relative positions of the intermediate electrode 12 with respect to the electret electrode 11. FIG. FIG. 8 is a diagram showing a vibration power generation element 10a of Modification 1; FIG. 10 is a diagram showing a vibration power generation element 10b of Modification 2; FIG. 11 is a diagram showing a vibration power generation element 10c of Modification 3; FIG. 5(a) is a top view of the vibration power generation element 10c, and FIG. 5(b) is a cross-sectional view of the BB cross section in FIG. 5(a) viewed from the -Y direction. FIG. 11 is a diagram showing a vibration power generation element 10d of Modification 4; FIG. 10 is a diagram showing a configuration of a vibration power generation device 10e of Modification 5 and a vibration power generation device 100b including the vibration power generation device 10e; FIG. 11 is a diagram showing the configuration of a vibration power generation element 10f of Modification 6;

(embodiment)
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a vibration power generation device 100 including a vibration power generation element 10 according to an embodiment of the present invention. The vibration power generator 100 is
It has a vibration power generation element 10 and a power supply device 40 . The capacitive vibration power generation element 10 has a first
It has an electret electrode 11a, a second electret electrode 11b, and an intermediate electrode 12 arranged between these two electret electrodes 11a and 11b.

The first electret electrode 11a is fixed to the support frame 13 and the intermediate electrode 1
2, negatively charged electrets 15a are formed as an example.
The second electret electrode 11b is also fixed to the support frame 13, and the intermediate electrode 1
2, negatively charged electrets 15b are formed as an example.

The electrets 15a and 15b are formed, for example, by performing a known electrification treatment described in Japanese Unexamined Patent Application Publication No. 2014-049557.
The electret 15a and the electret 15b are collectively referred to as the electret 15 as well.
Further, the electrodes on which the electrets 15 are formed, such as the first electret electrode 11a and the second electret electrode 11b, are collectively referred to as the electret electrodes 11 as well.

The intermediate electrode 12 is held by the support frame 13 via an elastically deformable holding portion 14 such as a spring. Therefore, when the vibration power generating element 10 including the support frame 13 vibrates in the X direction shown in FIG. It vibrates in the X direction relative to the second electret electrode 11b. Specifically, the capacitance between the intermediate electrode 12 and the first electret electrode 11a (interelectrode facing area) and the capacitance between the intermediate electrode 12 and the second electret electrode 11b (interelectrode facing area ) increase and decrease in opposite phases, relative vibration between the electrodes is generated accompanying the vibration of the intermediate electrode 12 . In this way, since the capacitance between the intermediate electrode 12 and the two electret electrodes 11 fluctuates in mutually opposite phases, a capacitance-type electrode in which the fixed comb-teeth electrode and the movable comb-teeth electrode that mesh with each other are moved relative to each other. Power generation efficiency is better than that of the vibration power generation element.

Relative vibration between the intermediate electrode 12 and the electret electrode 11 induces a positive or negative charge (positive charge in the first embodiment) in the first electret electrode 11a and the second electret electrode 11b, thereby generating AC power. be done. These charges are generated by a conductor wiring Wa connected to the first electret electrode 11a and a conductor wiring Wb connected to the second electret electrode 11b. is transmitted to

The power supply device 40 has a bridge-type full-wave rectifier circuit including four diodes D1 to D4. The wiring Wa is connected to the anode of the diode D1 and the cathode of the diode D2, and the wiring Wb is connected to the anode of the diode D4 and the cathode of the diode D3.
The cathode of the diode D1 and the cathode of the diode D4 are connected to the first output terminal Vo1 of the power supply device 40, the anode of the diode D2 and the anode of the diode D3 are connected to the second output terminal Vo2 of the power supply device 40, Maintained at ground potential.

One end of a charge injection wiring WI for injecting charge into the intermediate electrode 12 is connected to the intermediate electrode 12 .
The other end of the charge injection wiring WI is connected to one end of the resistance element RI. The other end of resistance element RI is connected to the anode of diode D2 and the anode of diode D3 in power supply device 40, that is, maintained at the ground potential.

The AC power generated by the vibration power generation element 10 by converting vibration energy is output by the power supply device 40 as power having a ground potential at the second output end Vo2 and a positive potential at the first output end Vo1.
Note that the power supply device 40 may include, for example, a capacitor or a voltage converter including a chopper-type DC-DC converter.

Hereinafter, the principle of operation of the vibration power generator 100 using the vibration power generation element 10 of the embodiment will be described with reference to FIG.
FIGS. 2A to 2C show the induced in each electrode at each relative position when the intermediate electrode 12 vibrates (moves) in the X direction with respect to the first electret electrode 11a and the second electret electrode 11b. It represents the state of charge in

FIG. 2(a) shows the charge state when the intermediate electrode 12 is at the middle point of vibration (hereinafter also referred to as the neutral point).
Since the +X side end of the intermediate electrode 12 faces the negative charge 16a of the electret 15a formed on the surface of the first electret electrode 11a, this portion has a positive charge 17a.
is induced.
Since the −X side end of the intermediate electrode 12 faces the negative charge 16b of the electret 15b formed on the surface of the second electret electrode 11b, this portion has a positive charge 17b.
is induced.

On the other hand, in the portion of the first electret electrode 11a that does not face the intermediate electrode 12, a negative charge 16a is induced by the electret 15a, and a positive charge 18a is induced inside the first electret electrode 11a.
In a portion of the second electret electrode 11b that does not face the intermediate electrode 12, negative charges 16b are induced by the electrets 15b, and positive charges 18b are induced inside the second electret electrode 11b.
FIG. 2(a) described above shows that no electromotive force is generated between the first electret electrode 11a and the second electret electrode 11b and no charge is transferred. In this sense, the position of the intermediate electrode 12 in FIG. 2A is called a neutral point, and the vibration power generation element 10 is called in a neutral state.

FIG. 2(b) shows a state in which the intermediate electrode 12 has relatively moved to the +X side compared to FIG. 2(a).
In the state of FIG. 2(b), the area of the portion facing the intermediate electrode 12 in the surface of the first electret electrode 11a is increased as compared with the state of FIG. 2(a). Therefore, the positive charge 17a of the intermediate electrode 12 induced by the negative charge 16a of the electret 15a increases. As a result, part of the positive charge 18a induced inside the first electret electrode 11a in the state of FIG. 2(a) becomes surplus charge 19a.

On the other hand, in the state of FIG. 2(b), compared with the state of FIG. 2(a), the second electret electrode 11
In the surface of b, the area of the portion facing the intermediate electrode 12 is reduced. Therefore, the positive charge 17b of the intermediate electrode 12 induced by the negative charge 16b of the electret 15b is reduced. As a result, in the interior of the second electret electrode 11b, a charge-deficient portion 20, which is a portion lacking positive charges to be induced with respect to the negative charges 16b of the electrets 15b, is generated.
b is produced.

Therefore, in the state of FIG. 2B, the first electret electrode 11a is positively charged and the second electret electrode 11b is negatively charged. Electricity can be generated by causing a current I1 to flow from the first electret electrode 11a to the second electret electrode 11b through the output circuit R by the electromotive force generated by this charging. Here, the resistor R provided between the first electret electrode 11a and the second electret electrode 11b represents the power supply device 40 in FIG.

On the other hand, FIG. 2(c) shows a state in which the intermediate electrode 12 has relatively moved to the −X side compared to FIG. 2(a). In the state of FIG. 2(c), compared with the state of FIG. 2(a), the second electret electrode 11b
A surplus charge 19b is generated inside the first electret electrode 11a, and a charge-deficient portion 20a, which is a portion lacking positive charges to be induced inside the first electret electrode 11a, is generated.
Therefore, in the state of FIG. 2(c), the first electret electrode 11a is negatively charged and the second electret electrode 11b is positively charged. Electricity can be generated by causing a current I2 to flow from the second electret electrode 11b to the first electret electrode 11a by the electromotive force generated by this charging.

Note that the intermediate electrode 12 includes the first electret electrode 11a and the second electret electrode 11.
b. It may be held by the holding portion 14 in a state of being insulated from the support frame 13 or the like, or the holding portion 14 itself may be made of an insulating material.

By the way, if charge is not injected into the intermediate electrode 12 by the charge injection wiring WI, when the environment in which the vibration power generation element 10 is installed is humid, the charge to be held in the intermediate electrode 12 may be lost in the atmosphere. There is a risk of discharge via water vapor or ions, or a charge that should have originally been induced in the intermediate electrode 12 may combine with ions in the gas and become neutral. In this specification, the intermediate electrode 12 being discharged as described above and becoming neutral are collectively referred to as neutralization of the intermediate electrode 12 .

FIG. 3 is a diagram showing the operation of the vibration power generation element 10 when the intermediate electrode 12 is neutralized.
3A to 3C, the intermediate electrode 12 is the first electret electrode 1, as in FIG.
It shows the state of charges induced in each electrode at each relative position when vibrating (moving) in the X direction with respect to 1a and second electret electrode 11b.
Hereinafter, based on the difference between the state shown in FIG. 3 and the state shown in FIG. 2, the operation of the vibration power generation element 10 when the charge in the intermediate electrode 12 is discharged will be described.

FIG. 3(a) is a diagram corresponding to FIG. 2(a) and shows the charge state when the intermediate electrode 12 is at the midpoint of the vibration. When the intermediate electrode 12 is discharged, no positive charge is induced in the portion 21a facing the first electret electrode 11a and the portion 21b facing the second electret electrode 11b of the intermediate electrode 12. Therefore, a positive charge 22a induced by the negative charge 16a of the electret 15a is generated inside the portion of the first electret electrode 11a facing the intermediate electrode 12. As shown in FIG. Second electret electrode 1
The negative charge 16a of the electret 15b is also inside the portion of the electret 1b facing the intermediate electrode 12.
A positive charge 22b induced by is generated.

FIG. 3(b) is a diagram corresponding to FIG. 2(b), showing a state in which the intermediate electrode 12 has relatively moved to the +X side from the position shown in FIG. 3(a).
FIG. 3(c) is a diagram corresponding to FIG. 2(c), showing a state in which the intermediate electrode 12 has moved relative to the −X side from the position shown in FIG. 3(a).
Unlike the case shown in FIG. 2, in the case of FIG. 3, there is no electric charge on the intermediate electrode 12, so that the intermediate electrode 12 changes from the state of FIG. 3(a) to the state of FIG. 3(b) or FIG. , the states of charges in the first electret electrode 11a, the second electret electrode 11b, and the intermediate electrode 12 do not change.

That is, when the intermediate electrode 12 is neutralized as shown in FIG. 3, even if the electret electrode 11 and the intermediate electrode 12 move (vibrate) relative to each other, either the first electret electrode 11a or the second electret electrode 11b Electricity cannot be generated even if the battery is put in place without causing excess electric charge or insufficient electric charge.

Therefore, in the vibration power generation element 10 of the embodiment, in order to prevent loss of charge from the intermediate electrode 12, the charge injection wiring WI and the resistance element RI are used to transfer the charge from the power supply 40 to the intermediate electrode 12.
It is configured to inject charge into the . The charge injection wiring WI and the resistive element RI can be interpreted as the charge injector 30 .

In the vibration power generation element 10, the charge of the electret 15 of the electret electrode 11 facing the intermediate electrode 12 is attracted to the intermediate electrode 12, and the charge of the electret 15 is transferred from the power supply 40 via the charge injector 30. Charges of opposite characteristics are injected. A positive charge is injected into the intermediate electrode 12 when the surfaces of the electret electrodes 11a and 11b are provided with negatively charged regions. Injection of positive charges from the charge injector 30 enables the vibration power generation element 10 to maintain charge in the intermediate electrode 12 over a long period of time, that is, to maintain high power generation efficiency over a long period of time. With a positively charged electret electrode and a negatively charged intermediate electrode, a negative charge is injected into the intermediate electrode.

It should be noted that the location where the charge injector 30 is connected is not limited to the anode of the diode D2 and the anode of the diode D3 in the power supply device 40 described above, and may be other location in the power supply device 40. FIG. However, even in the power supply device 40, electric charges are generated in a portion connected with low electrical resistance to the wiring Wa connected to the first electret electrode 11a or the wiring Wb connected to the second electret electrode 11b. Connecting the injector 30 is not preferred. Therefore,
The charge injector 30 may be connected to a portion of the power supply device 40 that is connected to the wiring Wa and the wiring Wb with a certain amount of electrical resistance.
Note that the resistance element RI that constitutes the charge injector 30 may be omitted.

(Modification 1)
FIG. 4 is a diagram showing the vibration power generation element 10a of Modification 1. As shown in FIG. Parts common to the vibration power generation element 10 of the above-described embodiment are denoted by the same reference numerals, and descriptions thereof are omitted.
A vibration power generation element 10a of Modification 1 has a plurality of electret electrodes 11 arranged in parallel, and an intermediate electrode 12 is arranged between each of the plurality of electret electrodes 11 .

Each intermediate electrode 12 is held by a support frame 13 via an elastically deformable holding portion 14 such as a spring so as to be able to vibrate in the X direction in the drawing. As in the above-described embodiment, each intermediate electrode 12 is connected to one end of a charge injection wiring WI (part of the charge injector 30 of the above-described embodiment) for injecting charges into the intermediate electrode 12. ing.
Of the electret electrodes 11, the first electret electrode 11a and the second electret electrode 11b are provided with electrets 15 on the side facing the intermediate electrode 12, as in the above-described embodiment.

Since the third electret electrode 11a1 and the fourth electret electrode 11b1 face the intermediate electrode 12 on both sides thereof, the electrets 15 are formed on both sides thereof.
is formed.
Wiring Wa is connected to the first electret electrode 11a and the third electret electrode 11a1.
is connected. On the other hand, a wiring Wb is connected to the second electret electrode 11b and the fourth electret electrode 11b1.
The first electret electrode 11a and the third electret electrode 11a1 are shifted in the +X direction with respect to the second electret electrode 11b and the fourth electret electrode 11b1.

When the intermediate electrode 12 vibrates relative to the electret electrode 11 in the X direction, the first electret electrode 11a and the third electret electrode 11a1 and the second electret electrode 11a1 and the second
Electric charges are induced in each of the electret electrode 11b and the fourth electret electrode 11b1. This enables power generation.
Also in Modification 1, the charge injection wiring WI (charge injector 3
0) is connected, the vibration power generation element 10a prevents neutralization of the intermediate electrode 12,
High power generation efficiency can be maintained over a long period of time.

(Modification 2)
FIG. 5 is a diagram showing a vibration power generation element 10b of Modification 2. As shown in FIG. Parts common to the vibration power generation element 10 of the above-described embodiment are denoted by the same reference numerals, and descriptions thereof are omitted.
In the vibration power generating element 10b of Modified Example 2, a plurality of electret electrodes 11 are fixedly arranged on the inner surface of the support frame 13a. Then, the plurality of intermediate electrodes 12a are connected to a conductive support 25.
The support member 25 is held by the support frame 13a through an elastically deformable insulating holding portion 14a such as a spring so as to be able to vibrate in the X direction in the figure. A charge injection wiring WI is connected to the conductive support 25, so that the conductive support 2 is connected to the plurality of intermediate electrodes 12a.
5, charges are injected from the charge injection wiring WI.

At the center position (neutral position) of vibration of the support 25 in the X direction, each of the plurality of intermediate electrodes 12a is connected to the first electret electrode 11a2 and the second electret electrode 1, respectively.
1b2 and are arranged so as to face each other with approximately the same area. Therefore, when the support 25 holding the intermediate electrodes 12a vibrates in the X direction, the areas of the opposing portions between the intermediate electrodes 12a and the first electret electrode 11a2 and the second electret electrode 11b2 change. That is, the areas of the opposing portions increase and decrease in opposite directions, in other words, in opposite phases.

As a result, charges are induced in the first electret electrode 11a2 and the second electret electrode 11b2, and power generation is performed, as in the above-described embodiment. A wiring Wa is connected to each first electret electrode 11a2, and a wiring Wb is connected to each second electret electrode 11b2, so that charges induced by the wirings Wa and Wb can be taken out. Since charges are injected into the intermediate electrode 12a by the charge injection wiring WI and neutralization is prevented,
The vibration power generation element 10b can maintain high power generation efficiency over a long period of time.

(Modification 3)
FIG. 6 is a diagram showing a vibration power generation element 10c of Modification 3. As shown in FIG. FIG. 6(a) shows the vibration power generation element 1
0c, and FIG. 6(b) is a cross-sectional view of the BB cross section in FIG. 6(a) viewed from the -Y direction. Parts common to the vibration power generation element 10 of the above-described embodiment are denoted by the same reference numerals, and descriptions thereof are omitted.

The vibration power generation element 10c of Modification 3 has a plurality of electret electrodes 11 similarly to the vibration power generation element 10a of Modification 1 described above, and intermediate electrodes 12b1 to 12b3 are arranged between each of the plurality of electret electrodes 11. ing.
Each of the intermediate electrodes 12b1 to 12b3 is supported by an elastically deformable holding portion 14b such as a thin metal plate.
It is held so as to be able to swing in the X direction in the drawing about the holding portion 14b. Holding portion 14b
A charge injection wiring WI is connected to the intermediate electrodes 12b1 to 12b3. Therefore, charges are injected by the charge injection wiring WI into the intermediate electrodes 12b1 to 12b3 via the conductive holding portion 14b. Holding portion 14b and support frame 1
An insulating member is provided between 3.

On the other hand, for each electret electrode 11, the first electret electrode 11a3 and the third electret electrode 11a4 connected to the wiring Wa are - They are displaced in the X direction. This state is shown in FIG.

6(b) is a cross-sectional view of the BB cross section in FIG. 6(a) as seen from the -Y direction. The fourth electret electrode 11b4 behind (+Y direction) is shown. Although the third electret electrode 11a4 indicated by a dashed line is located at -Y from the BB section in FIG. 6(a), it is shown in FIG. 6(b) for easy understanding. .
As shown in FIG. 6B, when the intermediate electrode 12b2 oscillates (vibrates) in the X direction due to vibration in the X direction, the area of the facing portion between the intermediate electrode 12b2 and the third electret electrode 11a4 and the fourth electret electrode 11b4 changes. That is, the areas of the opposing portions increase and decrease in opposite directions, in other words, in opposite phases.

As a result, charges are induced in the third electret electrode 11a4 and the fourth electret electrode 11b4, and power generation is performed, as in the above-described embodiment. another intermediate electrode 12b1,
The same applies to the electret electrode 11 facing 12b3.
Thereby, electric power can be generated. Since charges are injected into the intermediate electrodes 12b1 to 12b3 by the charge injection wiring WI and neutralization is prevented, the vibration power generation element 10c can maintain high power generation efficiency over a long period of time.

(Modification 4)
FIG. 7 is a diagram showing a vibration power generation element 10d of Modification 4. As shown in FIG. Parts common to the vibration power generation element 10 of the above-described embodiment are denoted by the same reference numerals, and descriptions thereof are omitted.
In the vibration power generation element 10d of the fourth modification, the first
Between the electret electrode 11a and the second electret electrode 11b fixed to the support frame 13 and connected to the wiring Wb, the first intermediate electrode 1 is arranged in order from the first electret electrode 11a side.
2c1, a fifth electret electrode 11c, and a second intermediate electrode 12c2 are arranged.

Each end of the first intermediate electrode 12c1 and the second intermediate electrode 12c2 is connected to an elastically deformable holding portion 14 such as a spring. One end of each holding portion 14 is connected to the support frame 13 and the other end is connected to a support frame extension 21 fixed to the support frame 13 . Therefore,
The first intermediate electrode 12c1 and the second intermediate electrode 12c2 are held by the support frame 13 so as to vibrate in the X direction in the figure.
A charge injection wiring WI is connected to each of the first intermediate electrode 12c1 and the second intermediate electrode 12c2.

The fifth electret electrode 11c is fixed to the support frame 13 by a holding mechanism (not shown).
The wiring Wa, the wiring Wb, and other output lines are not wired to the fifth electret electrode 11c, and the fifth electret electrode 11c is electrically floating. Since both surfaces of the fifth electret electrode 11c face the first intermediate electrode 12c1 and the second intermediate electrode 12c2, the electrets 15c are formed on both surfaces thereof.
Also in the vibration power generation element 10d of Modification 4, the first intermediate electrode 12c1
And the second intermediate electrode 12c2 and each electret electrode 11 are relatively vibrated in the X direction to generate power. Since electric charges are injected into the first intermediate electrode 12c1 and the second intermediate electrode 12c2 by the charge injection wiring WI and neutralization is prevented, the vibration power generation element 10d can maintain high power generation efficiency over a long period of time. can.

(Modification 5)
FIG. 8 is a diagram showing a vibration power generation device 10e of Modification 5 and a vibration power generation device 100b including the vibration power generation device 10e.
Since the vibration power generation element 10e and the vibration power generation device 100b of Modification 5 are mostly the same as the vibration power generation element 10 and the vibration power generation device 100 of the above-described embodiment, common parts are denoted by the same reference numerals. and the explanation is omitted.

Vibration power generation element 10e of Modification 5 includes charge injection wirings WI and MO as charge injector 30b.
and a switching element TI such as an SFET. The power supply device 40a is provided with a voltage conversion circuit VC, and the output voltage of the voltage conversion circuit VC is monitored by the voltage detection integrated circuit VD. The voltage detection integrated circuit VD sends a control signal to the switching element TI when the output voltage of the voltage conversion circuit VC falls below a predetermined value, and the switching element TI is turned on by this control signal. Thereby, electric charges are injected into the intermediate electrode 12 from the power supply device 40a.

When the output voltage of the voltage conversion circuit VC exceeds a predetermined value, the voltage detection integrated circuit VD does not transmit the control signal to the switching element TI, and the switching element TI is in the cutoff state.
In the vibration power generation element 10e of Modification 5, the injection of electric charge into the intermediate electrode 12 can be controlled by switching control of conduction or interruption of the switching element TI.

In Modified Example 5, the power supply device 4
A signal obtained by monitoring the voltage within 0a is used. Therefore, when the voltage in the power supply device 40a drops, that is, when the power generation efficiency of the vibration power generation element 10e drops, charge is injected into the intermediate electrode 12 to restore the power generation efficiency of the vibration power generation element 10e. can.
The control signal to the switching element TI is not limited to the signal obtained by monitoring the voltage in the power supply device 40a. For example, a trigger signal generated by a timer circuit at predetermined intervals is used as the control signal to the switching element TI. You can also

(Modification 6)
FIG. 9 is a diagram showing a vibration power generation element 10f of Modification 6. As shown in FIG.
Since most of the configuration of the vibration power generation element 10f of Modification 6 is the same as that of the vibration power generation element 10 of the above-described embodiment, common parts are denoted by the same reference numerals and description thereof is omitted.

The vibration power generation element 10f of Modification 6 includes a charge injection wiring WI having one end connected to the intermediate electrode 12, and a resistance element having one end connected to the other end of the charge injection wiring WI and the other end connected to the wiring Wa. RI1 and a resistive element RI2 having one end connected to the other end of the charge injection wiring WI and the other end connected to the wiring Wb. The charge injection wiring WI, the resistive element RI1, and the resistive element RI2 constitute the charge injector 30c.
The electrical resistance of the resistance element RI1 and the resistance element RI2 is equal to that of the vibration power generation element 10f.
It has a sufficiently large resistance value compared to the resistance due to the load of the power supply device 40 connected to the .

In the vibration power generating element 10f of Modification 6, charges are injected into the intermediate electrode 12 from the first electret electrode 11a through the resistance element RI1 and from the second electret electrode 11b through the resistance element RI2. Therefore, it is possible to prevent the charge in the intermediate electrode 12 from being lost due to discharge, and it is possible to maintain high power generation efficiency of the vibration power generation element 10f over a long period of time.

Note that the method of connecting the resistance element RI1 and the resistance element RI2 is not limited to the form described above. For example, the resistive element RI1 and the resistive element RI2 may be directly connected to the first electret electrode 11a and the second electret electrode 11b, respectively, without the wiring Wa and the wiring Wb.
Alternatively, one of the resistance elements RI1 and RI2 may be omitted, and charges may be injected into the intermediate electrode 12 from either the first electret electrode 11a or the second electret electrode 11b.

Also, the resistance elements RI1 and RI2 of the vibration power generation element 10f can be replaced with the switching element TI of Modification 5, or the resistance elements RI1 and RI2 and the switching element TI can be arranged in series. Accordingly, it is also possible to adopt a configuration in which charges are injected from the electret electrode 11 to the intermediate electrode 12 only when the voltage to be generated is lowered.
Further, the charge injectors 30, 30a, and 30b included in Modifications 5 and 6 are applied to the vibration power generation elements 10, 10a to 10d of Modifications 1 to 4 described above, and the intermediate electrode 12 , 12a, 12b can also be injected.

In the embodiment and each modified example described above, the electret electrode 11 is fixed to the support frame 13 and the intermediate electrode 12 vibrates or swings with respect to the support frame 13 . However, the configuration is not limited to this configuration, and a configuration in which the intermediate electrode 12 is fixed to the support frame 13 and the electret electrode 11 vibrates or swings with respect to the support frame 13 may be employed.

In the embodiment and each modified example, the direction of relative vibration between the intermediate electrode 12 and the electret electrode 11 is the direction (X direction) parallel to the surface of the electret electrode 11 facing the intermediate electrode 12. , the vibration direction is not limited to this direction. For example, by vibrating in a direction perpendicular to the facing surfaces, the distance between the electret electrode 11 and the intermediate electrode 12 facing each other is changed, and the capacitance of the capacitor formed by both electrodes is changed, thereby inducing charge. It can also be used to generate electricity.
However, the power generation efficiency can be further improved by making the direction of the relative vibration parallel to the surface of the electret electrode 11 facing the intermediate electrode 12 .

(Effects of Embodiment and Modifications)
(1) The vibration power generation elements 10, 10a to 10f of the embodiment and modifications described above are
In a vibration power generation element that outputs AC power from an output line by vibration from the outside, an intermediate electrode 12 that is not connected to the output line, and a surface of the surface facing the intermediate electrode 12 that is arranged to face the intermediate electrode A plurality of electret electrodes 11 having electrets 15 at least in part thereof, a holding portion 14 for holding the intermediate electrode 12 and the plurality of electret electrodes 11 so as to freely relatively vibrate each other, and a surface of the plurality of electret electrodes 11 on the intermediate electrode 12. and a charge injector 30 for injecting a charge having a characteristic opposite to that of the electret 15 formed in . In the embodiment, vibration of the intermediate electrode 12 causes the intermediate electrode 12 and the plurality of electret electrodes 11 to vibrate.
and vibrate relative to each other.
With this configuration, neutralization of the intermediate electrode 12 can be prevented, and the vibration power generation elements 10 and 10a can be prevented.
Vibrational energy in the environment where ~10f is installed can be efficiently converted into electric energy over a long period of time. In other words, power generation efficiency can be improved.

(2) Furthermore, by making the direction of relative vibration between the electret electrodes 11 and the intermediate electrodes 12 parallel to the surfaces of the plurality of electret electrodes 11 facing the intermediate electrodes 12, the power generation efficiency can be further improved. Thus, even with a vibration power generating element of the same size as the conventional one, it is possible to generate a larger amount of electric power.
(3) In (2), when the intermediate electrode 12 moves in the first direction relative to the plurality of electret electrodes 11, the area of the facing portion between one of the plurality of electret electrodes 11 and the intermediate electrode 12 increases, and the other one of the plurality of electret electrodes 11 and the intermediate electrode 1
When the area of the facing portion decreases and moves in a second direction different from the first direction, the area of the facing portion increases or decreases opposite to the case of movement in the first direction. , the power generation efficiency can be further improved.

(4) In (1) to (3), the charge injector 30 is
A part of the circuit (power supply device 40 ) to which power is supplied from the intermediate electrode 12 may be connected to the intermediate electrode 12 .
(5) In (1) to (3), the charge injector 30 includes resistance elements RI1 and RI2, one end of the charge injector 30 is connected to the intermediate electrode 12, and the other end is connected to at least one of the plurality of electret electrodes 11. A configuration in which they are connected to one is also possible.
(6) In the above structure, a control member (switching element TI) for controlling charge injection to the intermediate electrode 12 by the charge injector 30 may be provided. This configuration allows charge to be injected into intermediate electrode 12 by charge injector 30 only when needed.

(7) The vibration power generators 100, 100a, 100b described above include the vibration power generators 10, 10a to 10f of the above embodiments and modifications, and the power supply devices 40, 40a. With this configuration, it is possible to efficiently convert energy of vibration in the environment where the vibration power generators 100, 100a, and 100b are installed into electric energy. In other words, power generation efficiency can be improved.

Although various embodiments and modifications have been described above, the present invention is not limited to these contents. Moreover, each embodiment and modification may be applied independently, respectively, and may be used in combination. Other aspects conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention.

100, 100a, 100b... Vibration power generator, 10, 10a to 10f... Vibration power generator,
Reference Signs List 11 electret electrode 11a first electret electrode 11b second electret electrode 12, 12a intermediate electrode 13, 13a support frame 14, 14a holding portion 1
5, 15a, 15b... electret, 30, 30a-30c... charge injector, 40... power supply circuit, D1-D4... diode, VC... voltage conversion circuit, VD... integrated circuit for voltage detection

Claims (7)

In the vibration power generation element that outputs AC power from the output line by vibration from the outside,
an intermediate electrode that does not have an electret and is not connected to the output line;
a plurality of electret electrodes arranged to face the intermediate electrode and having electrets on at least part of a surface of a surface facing the intermediate electrode;
a holding unit that holds the intermediate electrode and the plurality of electret electrodes so that they can vibrate relative to each other;
and a charge injector that injects into the intermediate electrode a charge having characteristics opposite to the characteristics of the electrets formed on the surfaces of the plurality of electret electrodes. In the vibration power generation element according to claim 1,
The vibration power generation element, wherein the direction of the relative vibration is parallel to the surface of the plurality of electret electrodes facing the intermediate electrode. In the vibration power generation element according to claim 2,
When the intermediate electrode moves in the first direction relative to the plurality of electret electrodes due to the relative vibration, the area of the facing portion between one of the plurality of electret electrodes and the intermediate electrode increases, When the area of the opposing portion between the other one of the plurality of electret electrodes and the intermediate electrode decreases and moves in the second direction different from the first direction, the area of the opposing portion decreases to the second direction. A vibration power generation element that increases and decreases in the opposite direction to movement in one direction. In the vibration power generation element according to any one of claims 1 to 3,
The vibration power generation element, wherein the charge injector connects a part of a circuit that receives power supply from the vibration power generation element to the intermediate electrode. In the vibration power generation element according to any one of claims 1 to 3,
The vibration power generation device, wherein the charge injector includes a resistive element, one end of the charge injector is connected to the intermediate electrode, and the other end is connected to at least one of the plurality of electret electrodes. In the vibration power generation element according to claim 4 or claim 5,
A vibration power generation element, comprising a control member for controlling injection of charges into the intermediate electrode by the charge injector. The vibration power generation element according to any one of claims 1 to 6;
A vibration power generator, comprising: a power supply.

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