WO2015050009A1

WO2015050009A1 - Insulated piezoelectric transformer

Info

Publication number: WO2015050009A1
Application number: PCT/JP2014/074925
Authority: WO
Inventors: 宏志浅野
Original assignee: 株式会社村田製作所
Priority date: 2013-10-03
Filing date: 2014-09-19
Publication date: 2015-04-09
Also published as: JP6172286B2; JPWO2015050009A1

Abstract

An insulated piezoelectric transformer (Tr) uses a third order vertical oscillation mode. The insulated piezoelectric transformer (Tr) comprises a piezoelectric body (PB) having a length of 3λ/2, where the wavelength of a resonant frequency is λ. The piezoelectric body (PB) has, in the following order following the length direction, a first high voltage section (Hv1), a low voltage section (Lv1), and a second high voltage section (Hv2). A first low voltage electrode (EL1) and a second low voltage electrode (EL2) are provided to a pair of ends of the first low voltage section (Lv1) in the thickness direction of the piezoelectric body (PB). A first high voltage electrode (EH1) and a second high voltage electrode (EH2) are provided to a pair of ends in the length direction of the piezoelectric body (PB). The first low voltage electrode (EL1) and the second low voltage electrode (EL2) are physically separated from the first high voltage electrode (EH1) and the second high voltage electrode (EH2).

Description

Insulation type piezoelectric transformer

The present invention relates to an insulation type piezoelectric transformer.

For example, Patent Document 1 discloses an insulating piezoelectric transformer that can insulate an input-side circuit from an output-side circuit. Patent Document 1 discloses a technique for providing an unpolarized region between a polarization region that constitutes an input region and a polarization region that constitutes an output region, thereby improving the insulation between the input region and the output region. ing.

JP 2003-8098 A

The insulation-type piezoelectric transformer described in Patent Document 1 has an unpolarized region, and thus becomes large.

The present invention provides an insulation type piezoelectric transformer capable of improving insulation while suppressing an increase in size.

The insulated piezoelectric transformer of the present invention is an insulated piezoelectric transformer that uses a longitudinal vibration mode of order n (n is an integer of 3 or more). The insulated piezoelectric transformer includes a piezoelectric body having a length of nλ / 2 where λ is a wavelength at a resonance frequency. The piezoelectric body has a first high voltage portion, a low voltage portion, and a second high voltage portion in order along the length direction. The low voltage portion has an integer number of polarization regions having a length of λ / 2 along the length direction of the piezoelectric body. Each of the first high voltage part and the second high voltage part has an integral number of polarization regions having a length of λ / 2 along the length direction of the piezoelectric body. When the polarization direction of the polarization region constituting the low voltage part is parallel to the thickness direction of the piezoelectric element body and the number of polarization regions constituting the low voltage part is two or more, the length of the piezoelectric element body The odd-numbered and even-numbered ones are set so as to be in the same direction from one end side in the direction, and the odd-numbered and even-numbered polarized regions are set in opposite directions. The polarization directions of the polarization regions constituting the first high-voltage part and the second high-voltage part are parallel to the length direction of the piezoelectric body and odd-numbered from one end side in the length direction of the piezoelectric body. The even numbers are set to have the same direction, and the odd numbered polarization region and the even numbered polarization region are set to be in opposite directions. Low voltage electrodes are respectively provided at a pair of end portions in the thickness direction of the piezoelectric body of the low voltage portion. High-voltage electrodes are respectively provided at a pair of end portions in the length direction of the piezoelectric body. The low voltage electrode and the high voltage electrode are physically separated.

In the present invention, the insulating piezoelectric transformer of the present invention is provided, the power receiving electrode is connected to the high voltage electrode of the insulating piezoelectric transformer, and the input of the power receiving circuit is connected to the low voltage electrode of the insulating piezoelectric transformer. A power receiving device for a wireless power transmission system is provided.

In the present invention, the insulation type piezoelectric transformer of the present invention is provided, the output of the power transmission circuit is connected to the low voltage electrode of the insulation type piezoelectric transformer, and the power transmission electrode is connected to the high voltage electrode of the insulation type piezoelectric transformer. A power transmission device for a wireless power transmission system is provided.

In the insulated piezoelectric transformer of the present invention, the low voltage electrode and the high voltage electrode are physically separated without providing an unpolarized region. Therefore, it is possible to improve insulation while suppressing an increase in size in the insulation type piezoelectric transformer.

It is a figure which shows the structure of the electric field coupling type | mold wireless power transmission system with which the insulation type piezoelectric transformer which concerns on this invention was applied to the power receiving apparatus. It is a figure which shows an example of the specific structure of the power receiving apparatus which comprises the electric field coupling type wireless power transmission system of Embodiment 1. 1 is a diagram illustrating a configuration of an insulating piezoelectric transformer according to a first embodiment. FIG. 5 is a diagram illustrating a configuration of an insulating piezoelectric transformer according to a second embodiment. FIG. 5 is a diagram illustrating a configuration of an insulating piezoelectric transformer according to a third embodiment. FIG. 6 is a diagram illustrating a configuration of an insulating piezoelectric transformer according to a fourth embodiment. FIG. 5 is a perspective view showing one end side of an insulation type piezoelectric transformer of Embodiments 1 to 4. FIG. 6 is a perspective view of an insulation type piezoelectric transformer according to a modification of the first embodiment. 10 is a perspective view of an insulation type piezoelectric transformer of a modification of the second embodiment. FIG. FIG. 10 is a perspective view of an insulation type piezoelectric transformer of a modification of the third embodiment. FIG. 10 is a perspective view of an insulation type piezoelectric transformer according to a modification of the fourth embodiment. It is a figure which shows an example of the attachment state of the insulation type piezoelectric transformer shown in FIG. The figure which shows the example which couple | bonded the surface electrode of the electrode for 1st high voltage of the insulation type piezoelectric transformer and the electrode for 2nd high voltage, the electrode for 1st low voltage, and the electrode for 2nd low voltage with the plate-shaped electrode with solder. is there. FIG. 9 is a diagram illustrating a configuration of an insulating piezoelectric transformer according to a fifth embodiment. FIG. 10 is a diagram illustrating a configuration of an insulating piezoelectric transformer according to a sixth embodiment. It is a figure which shows the structure of the electric field coupling type | mold wireless power transmission system with which the insulation type piezoelectric transformer which concerns on this invention was applied to the power transmission apparatus and the power receiving apparatus.

(Background of the Invention)
In a wireless power transmission system such as an electric field coupling type wireless power transmission system, for the purpose of improving power transmission efficiency, the power transmission device is provided with a step-up transformer that boosts a transmission voltage applied between a pair of power transmission electrodes. In some cases, a step-down transformer is provided to step down the voltage induced between the pair of power receiving electrodes. However, when a winding transformer is used as the step-up transformer and the step-down transformer, for example, the power transmission device and the power reception device are increased in size. The power receiving device is, for example, a smartphone or a tablet terminal, but these power receiving devices are required to be downsized. In order to reduce the size, for example, it is conceivable to use a piezoelectric transformer that is smaller than a wound transformer.

In a power receiving device that uses a piezoelectric transformer as a step-down transformer, in order to stabilize the reference potential (substantially equal to the ground potential) on the power receiving device side, the circuit on the input side and the output side are insulated as a piezoelectric transformer. It is desirable to use an insulation type piezoelectric transformer that can insulate the circuit on the input side and the output side instead of a Rosen type piezoelectric transformer or the like that cannot be used. As an insulation type piezoelectric transformer, there exists a thing of the above-mentioned patent document 1, for example. As described above, Patent Document 1 discloses a technique for improving insulation between an input region and an output region by providing an unpolarized region between a polarization region constituting an input region and a polarization region constituting an output region. Is disclosed. However, when an unpolarized region is provided in order to improve insulation as in the piezoelectric transformer described in Patent Document 1, there is a problem that the piezoelectric transformer becomes large. The present invention provides a technique that can cope with this problem.

(Embodiment 1)
1. Configuration 1-1. Configuration of Electric Field Coupled Wireless Power Transmission System FIG. 1 is a diagram showing a configuration of an electric field coupled wireless power transmission system to which an insulation type piezoelectric transformer of the present invention is applied. In FIG. 1, from the viewpoint of simplifying the illustration, the positions and number of electrodes (each high voltage electrode and each low voltage electrode) of the step-down transformer Tr are different from actual ones.

The electric field coupling type wireless power transmission system includes a power transmission device 100 and a power reception device 200.

The power transmission device 100 includes a power transmission circuit 110 and a pair of power transmission electrodes Eta and Etp (hereinafter, referred to as “power transmission side active electrode Eta” and “power transmission side passive electrode Etp” as appropriate). The power transmission circuit 110 generates an alternating voltage having a predetermined frequency and applies it between the pair of power transmission electrodes Eta and Etp. The pair of power transmission electrodes Eta and Etp constitute a capacitor C1.

The power receiving apparatus 200 receives a pair of power receiving electrodes Era and Erp (hereinafter referred to as “power receiving side active electrode Era” and “power receiving side passive electrode Erp” as appropriate) and an AC voltage induced between the pair of power receiving electrodes Era and Erp. It has a step-down transformer Tr that steps down and a load circuit 210 that receives the stepped-down AC voltage. The load circuit 210 receives a reduced AC voltage and executes a predetermined function.

FIG. 2 is a diagram illustrating an example of a specific configuration of the power receiving device 200 illustrated in FIG. The power receiving device 200 of this example includes the pair of power receiving electrodes Era and Erp, the step-down transformer Tr, and the load circuit 210 described above.

When the power transmission side active electrode Eta and the power reception side active electrode Era are in an opposing state, a coupling capacitance Caa occurs between the power transmission side active electrode Eta and the power reception side active electrode Era, and the power transmission side passive electrode Etp and the power reception side A coupling capacitance Cpp is generated between the passive electrode Erp. When the power transmission side active electrode Eta and the power reception side active electrode Era are in an opposing state, an alternating voltage is applied between the pair of power transmission electrodes Eta and Etp of the power transmission device 100, whereby the pair of power reception electrodes Era of the power reception device 200. , An AC voltage is induced between Erp. Thereby, electric power can be transmitted from the power transmission device 100 to the power reception device 200 in a state where the power transmission electrodes Eta and Etp and the power reception electrodes Era and Erp are not in contact with each other.

The pair of power receiving electrodes Era and Erp constitute a capacitor C2 which is a capacitance generated between the power receiving electrodes.

The step-down transformer Tr is composed of an insulating piezoelectric transformer. Details will be described later. In the following description, the step-down transformer Tr is referred to as an insulating piezoelectric transformer Tr.

The load circuit 210 includes a rectifier circuit REC, a regulator REG, and a load LD.

The rectifier circuit REC includes a plurality of diodes D1, D2, D3, D4, an inductor L3, and a capacitor C3. The rectifier circuit REC converts an AC voltage applied between a pair of input terminals into a DC voltage, and between the input terminals of the regulator REG. Apply.

The regulator REG converts the DC voltage output from the rectifier circuit REC into a predetermined DC voltage and outputs it.

The load LD performs a predetermined function such as charging of the rechargeable battery using the DC voltage output from the regulator REG.

1-2. Configuration of Insulating Piezoelectric Transformer FIG. 3 is a diagram illustrating a configuration of the insulating piezoelectric transformer Tr according to the first embodiment.

This insulation type piezoelectric transformer Tr is a piezoelectric transformer configured using a longitudinal vibration mode of order 3, where the wavelength at the resonance frequency is λ, and the length is 3λ / 2 (the length in the horizontal direction in FIG. 3). And a piezoelectric body PB having a width of less than λ / 2 (length in the direction perpendicular to the paper surface in FIG. 3) and a thickness of less than λ / 2 (length in the vertical direction of the paper surface in FIG. 3). .

The piezoelectric element body PB is formed using piezoelectric ceramics. The piezoelectric body PB has a first high voltage part Hv1, a low voltage part Lv1, and a second high voltage part Hv2 in order along the length direction.

The low voltage part Lv1 has one polarization region Lv11.

The first high voltage part Hv1 has one polarization region Hv11. The second high voltage part Hv2 has one polarization region Hv21.

The polarization region Hv11 of the first high voltage part Hv1, the polarization region Lv11 of the low voltage part Lv1, and the polarization region Hv21 of the second high voltage part Hv2 each have a length of λ / 2. Accordingly, the lengths of the first high voltage part Hv1 and the second high voltage part Hv2 are λ / 2, which are equal to each other.

A first low voltage electrode EL1 and a second low voltage electrode EL2 are provided at a pair of ends in the thickness direction of the piezoelectric body PB in the polarization region Lv11 of the low voltage portion Lv1.

A first high-voltage electrode EH1 and a second high-voltage electrode EH2 are provided at a pair of end portions in the length direction of the piezoelectric body PB.

In FIG. 3, the arrows shown in the blocks indicating the polarization region Lv11 of the low voltage portion Lv1, the polarization region Hv11 of the first high voltage portion Hv1, and the polarization region Hv21 of the second high voltage portion Hv2 are the polarization directions of the polarization regions. Indicates.

Here, the concept regarding the setting of the polarization direction of each polarization region constituting the insulated piezoelectric transformer according to each embodiment of the present invention will be described.

As described above, the insulation type piezoelectric transformer Tr of the present invention is a piezoelectric transformer configured using a longitudinal vibration mode of order n, and has a length of nλ / 2, where λ is a wavelength at a resonance frequency. A piezoelectric body PB is provided. The piezoelectric body PB has n polarization regions along the length direction. Each of the n polarization regions has a length of λ / 2. In the longitudinal vibration mode, each polarization region expands and contracts in the length direction of the piezoelectric body PB according to changes in the magnitude and direction of the electric field applied to the piezoelectric body PB. In the present invention, the polarization direction is set so that the expansion / contraction state of the n polarization regions is reversed between the even-numbered polarization region and the odd-numbered polarization region from one end side in the length direction of the piezoelectric body PB. Is set. For example, in the length direction of the piezoelectric body PB having n polarization regions, the first polarization region is “extended state”, the second polarization region is “contracted”, and the third polarization region is “extended state”. The polarization direction is set so that the “extended state” and the “contracted state” appear alternately in the fourth polarization region, such as “contracted state”. In other words, the direction of stress in each polarization region when an electric field is applied to the piezoelectric body PB (see FIG. 3. In FIG. 3, the stress is shown as a sine wave, but when the sine wave in FIG. 3 is positive In the figure, for example, rightward stress is generated, and when negative, for example, leftward stress is generated), the even-numbered polarization region and the odd-numbered polarization from one end side in the length direction of the piezoelectric body PB. The polarization direction of each polarization region is set so as to be opposite to the region (opposite direction).
In the present embodiment, the shape of the cross section perpendicular to the length direction of the piezoelectric body PB is a rectangle, but this shape is easy to manufacture and suitable for the appearance of the longitudinal vibration mode. However, the cross-sectional shape of the piezoelectric body PB is not limited to this. The cross-sectional shape of the piezoelectric body PB may be a circle, a triangle, or a pentagon or more polygon as long as vibration can be generated in the longitudinal vibration mode in the length direction of the piezoelectric body PB. Moreover, it can suppress that an unnecessary vibration mode arises by making the width | variety and thickness of the piezoelectric body PB into less than (lambda) / 2, respectively. The same applies to each embodiment described later.

More specifically, in the high-voltage part, the polarization direction of the polarization region constituting the high-voltage part is parallel to the length direction of the piezoelectric body PB and the length direction of the piezoelectric body PB. The polarization direction of the even-numbered polarization region and the polarization direction of the odd-numbered polarization region from one end side are set to be opposite to each other. Accordingly, the polarization directions of adjacent polarization regions are opposite to each other.

More specifically, the polarization direction of the polarization region constituting the high voltage part is:
(1) In the odd-numbered polarization region from one end side in the length direction of the piezoelectric body PB, they are in the same direction.
(2) In the even-numbered polarization region from one end side in the length direction of the piezoelectric body PB, they are in the same direction, and
(3) The odd-numbered polarization regions according to (1) and the even-numbered polarization regions according to (2) are set to be opposite to each other.

On the other hand, the polarization direction of the polarization region constituting the low voltage portion is parallel to the thickness direction of the piezoelectric body PB, and when there are two or more polarization regions, the length direction of the piezoelectric body PB The even-numbered polarization region and the odd-numbered polarization region are set in opposite directions from one end side. This is due to the following reason. That is, the expansion / contraction state in the length direction of the piezoelectric body PB is reversed between adjacent polarization regions of the piezoelectric body PB, and the expansion / contraction state in the thickness direction of the piezoelectric body PB is also reversed. is there. Considering this, in the low voltage part, the polarization directions of adjacent polarization regions are opposite to each other in the thickness direction of the piezoelectric body PB so that the voltages generated by the piezoelectric effect in the thickness direction have the same phase. Is set.

More specifically, the polarization direction of the polarization region constituting the low voltage part is (when two or more polarization regions exist)
(1) In the odd-numbered polarization region from one end side in the length direction of the piezoelectric body PB, they are in the same direction.
(2) In the even-numbered polarization region from one end side in the length direction of the piezoelectric body PB, they are in the same direction, and
(3) The odd-numbered polarization region according to (1) and the even-numbered polarization region according to (2) are set to be opposite to each other.

According to the piezoelectric transformer Tr having the above-described configuration, when an AC voltage is input (applied) between the high-voltage electrodes EH1, expansion / contraction (stress) is generated in each polarization region constituting each high-voltage portion due to the inverse piezoelectric effect. Due to (stress), expansion and contraction (stress) occurs in each polarization region constituting each low-voltage part, and a reduced AC voltage is output between the low-voltage electrodes by the piezoelectric effect due to the expansion and contraction (stress).

Based on the concept of setting the polarization direction, in the present embodiment, the polarization direction of the polarization region Lv11 constituting the low voltage portion Lv1 is parallel to the thickness direction of the piezoelectric body PB.

Further, the polarization directions of the polarization region Hv11 constituting the first high voltage part Hv1 and the polarization region Hv21 constituting the second high voltage part Hv2 are parallel to the length direction of the piezoelectric body PB. Further, the polarization region Hv11 constituting the first high voltage part Hv1 and the polarization region Hv21 constituting the second high voltage part Hv2 are first and third from one end side (left end side) in the length direction of the piezoelectric body PB. In other words, both are odd-numbered polarization regions. Therefore, the polarization direction of the polarization region Hv11 and the polarization direction of the polarization region Hv21 are set to the same direction.

In the insulated piezoelectric transformer Tr configured as described above, when the AC voltage V1 is input (applied) between the first high-voltage electrode EH1 and the second high-voltage electrode EH2, the reduced AC voltage V2 is supplied to the first high-voltage electrode EH1. It is output between the first low voltage electrode EL1 and the second low voltage electrode EL2.

In the insulated piezoelectric transformer Tr of the present embodiment, the low voltage electrode EL1, the second low voltage electrode EL2, and the high voltage electrode EH1 are physically separated without providing an unpolarized region. Therefore, it is possible to improve the insulation while suppressing the increase in size of the insulating piezoelectric transformer Tr.

Here, applying an AC voltage between the first high-voltage electrode EH1 and the second high-voltage electrode EH2 that are not grounded applies a voltage of + V to the first high-voltage electrode EH1, (2) A voltage of −V is applied to the high voltage electrode EH2. Since the first low-voltage electrode EL1 and the second low-voltage electrode EL2 are floating electrodes insulated from the first high-voltage electrode EH1 and the second high-voltage electrode EH2, the first high-voltage electrode EL2 When an AC voltage is applied between the EH1 and the second high voltage electrode EH2, the low voltage portion Lv1 is bypassed via the first low voltage electrode EL1 and the second low voltage electrode EL2 (see FIG. 3, the electric field E <b> 1 in the same direction is generated in the first high voltage part Hv <b> 1 and the second high voltage part Hv <b> 2. When the direction of the electric field E1 changes according to the periodic change of the AC voltage applied between the first high voltage electrode EH1 and the second high voltage electrode EH2, the first high voltage portion Hv1 (polarization region Hv11). ) And the second high voltage portion Hv2 (polarization region Hv21) expand and contract in the length direction according to the periodic change of the AC voltage, and the first low voltage portion Lv1 (polarization region Lv11) also extends in the length direction along with the expansion and contraction. It is forcibly expanded and contracted. By the expansion and contraction in the length direction, the first low voltage part Lv1 (polarization region Lv11) is forcibly expanded and contracted in the thickness direction, and the first low voltage part Lv1 (polarization region Lv11) is generated by the piezoelectric effect due to the expansion and contraction in the thickness direction. AC voltage is generated in the thickness direction, and the generated AC voltage is output between the first low voltage electrode EL1 and the second low voltage electrode EL2.

In the present embodiment, since the length of the first high voltage portion Hv1 and the length of the second high voltage portion Hv2 are equal to each other, an alternating current is generated between the first high voltage electrode EH1 and the second high voltage electrode EH2. When the voltage V1 is applied, the input AC voltage V1 is reduced in the low voltage portion Lv1 located between the first high voltage portion Hv1 and the second high voltage portion Hv2, that is, in the longitudinal center of the piezoelectric body PB. The potential induced by the electric field E1 is 0 (zero). Therefore, the insulation between the input and output of the insulation type piezoelectric transformer Tr can be improved without providing an unpolarized region. Further, only the voltage generated in the low voltage portion Lv1 due to the piezoelectric vibration of the piezoelectric body PB is output between the first low voltage electrode EL1 and the second low voltage electrode EL2. Thus, according to this embodiment, it is possible to provide the piezoelectric transformer Tr with improved insulation.

In this embodiment, since an unpolarized region that does not contribute to power conversion is not provided, a reduction in coupling coefficient and a reduction in power conversion efficiency are unlikely to occur.

In the piezoelectric transformer of this embodiment, the following effects (1) to (3) can also be obtained.

(1) The piezoelectric transformer of the present embodiment does not have an unpolarized region that does not contribute to power conversion. For this reason, the coupling coefficient and the power conversion efficiency are unlikely to decrease.

(2) In the piezoelectric transformer of the present embodiment, the high voltage portion and the low voltage portion are arranged alternately, that is, dispersedly in the length direction of the piezoelectric body PB. Further, about half of the plurality of polarization regions constituting the piezoelectric body PB is a polarization region constituting the high voltage portion. As a result, when an AC voltage having a predetermined frequency for causing longitudinal vibration of a predetermined order (third order in the present embodiment) is applied between the high voltage parts, vibration in the length direction of the piezoelectric body PB is predetermined. It becomes easy to be restrained by the longitudinal vibration of the order. Therefore, longitudinal vibrations of other orders close to a predetermined order are unlikely to occur. Therefore, power conversion can be performed efficiently.

(3) The piezoelectric transformer of this embodiment is an insulating piezoelectric transformer in which the high-voltage electrode and the low-voltage electrode are physically separated as described above. Therefore, it is possible to suppress transmission of noise such as fluctuations in the reference potential between the primary side and the secondary side.

It should be noted that the effects (1) to (3) are also exhibited in each embodiment described later.

2. Summary The insulated piezoelectric transformer Tr of this embodiment is an insulated piezoelectric transformer that uses a longitudinal vibration mode of order n (n is an integer of 3 or more). The insulated piezoelectric transformer Tr includes a piezoelectric body PB having a length of nλ / 2 where λ is a wavelength at a resonance frequency. In the present embodiment, the order n of the longitudinal vibration mode is 3, and the piezoelectric body PB sequentially passes the first high voltage part Hv1, the low voltage part Lv1, and the second high voltage part Hv2 along the length direction. Have. The low voltage portion Lv1 has a polarization region Lv11 having a length of λ / 2, and the first high voltage portion Hv1 and the second high voltage portion Hv2 are each a polarization region Hv11 having a length of λ / 2, Hv21. The polarization direction of the polarization region Lv11 constituting the low voltage part Lv1 is a direction parallel to the thickness direction of the piezoelectric body PB. The polarization directions of the polarization regions Hv11 and Hv12 constituting the first high voltage part Hv1 and the second high voltage part Hv2 are parallel to the length direction of the piezoelectric body PB and are the same direction. A first low voltage electrode EL1 and a second low voltage electrode EL2 are provided at a pair of end portions in the thickness direction of the piezoelectric body PB of the low voltage portion Lv1. A first high-voltage electrode EH1 and a second high-voltage electrode EH2 are provided at a pair of ends in the length direction of the piezoelectric body PB. The first low voltage electrode EL1 and the second low voltage electrode EL2, and the first high voltage electrode EH1 and the second high voltage electrode EH2 are physically separated.

In the insulation type piezoelectric transformer Tr of the present embodiment, an unpolarized region is not provided, and the first low voltage electrode EL1, the second low voltage electrode EL2, the first high voltage electrode EH1, and the second high voltage electrode EH2. Are physically separated. Therefore, it is possible to improve insulation while suppressing the increase in size of the insulation-type piezoelectric transformer.

In the present embodiment, the number of polarization regions constituting the first high voltage part Hv1 and the number of polarization regions constituting the second high voltage part Hv2 are the same, and the length of the first high voltage part Hv1 and the second high voltage part Hv1 are the same. The length of the voltage part Hv2 is equal.

As a result, when an AC voltage is applied between the first high voltage electrode EH1 and the second high voltage electrode EH2, it is between the first high voltage part Hv1 and the second high voltage part Hv2, that is, the piezoelectric element. In the low voltage part Lv1 located in the center in the longitudinal direction of the body PB, the potential due to the AC voltage is 0 (zero). Therefore, the insulation between the input and output of the insulation type piezoelectric transformer Tr can be improved.

In the present embodiment, the piezoelectric body PB has a width of less than λ / 2 and a thickness of less than λ / 2. Thereby, it can suppress by generating an unnecessary vibration mode.

In this embodiment, the piezoelectric transformer is applied to an electric field coupling type power receiving device. Accordingly, the electric field coupling type power receiving device can be reduced in size and height.

(Embodiment 2)
In the second embodiment, the insulation type piezoelectric transformer Tr is configured using a longitudinal vibration mode of order 4.

FIG. 4 is a diagram illustrating a configuration of an insulating piezoelectric transformer according to the second embodiment.

The insulated piezoelectric transformer Tr includes a piezoelectric body PB having a length of 4λ / 2, a width of less than λ / 2, and a thickness of less than λ / 2, where λ is a wavelength at a resonance frequency.

The low voltage portion Lv1 has two polarization regions Lv11 and Lv12 arranged along the length direction of the piezoelectric body PB.

The polarization region Hv11 of the first high voltage part Hv1, the polarization region Lv11 of the low voltage part Lv1, the polarization region Lv12 of the low voltage part Lv1, and the polarization region Hv21 of the second high voltage part Hv2 each have a length of λ / 2. Have. Accordingly, the lengths of the first high voltage part Hv1 and the second high voltage part Hv2 are λ / 2, which are equal to each other.

The polarization directions of the polarization region Lv11 and the polarization region Lv12 of the low voltage part Lv1 are parallel to the thickness direction of the piezoelectric body PB. The polarization region Lv11 is the second or even-numbered polarization region from one end side (left end side) in the length direction of the piezoelectric body PB, and the polarization region Lv12 is the length direction of the piezoelectric body PB. Since it is the third or odd-numbered polarization region from one end side, the polarization region Lv11 and the polarization region Lv12 are polarized in opposite directions.

The polarization directions of the polarization region Hv11 of the first high voltage part Hv1 and the polarization region Hv21 of the second high voltage part Hv2 are parallel to the length direction of the piezoelectric body PB. Here, the polarization region Hv11 of the first high-voltage part Hv1 is the first or odd-numbered polarization region from one end side (left end side) in the length direction of the piezoelectric body PB, and the second high-voltage part Hv2 The first polarization region Hv21 is the fourth or even-numbered polarization region from the one end side in the length direction of the piezoelectric body PB. Therefore, the polarization region Hv11 of the first high voltage part Hv1 and the polarization region Hv21 of the second high voltage part Hv2 are polarized in opposite directions.

In the polarization region Lv11 and the polarization region Lv12 of the low voltage portion Lv1, a first low voltage electrode EL1 and a second low voltage electrode EL2 are provided at a pair of ends in the thickness direction of the piezoelectric body PB, respectively. ing.

The first low voltage electrode EL1 in the polarization region Lv11 and the first low voltage electrode EL1 in the polarization region Lv12 are electrically connected to each other, and the second low voltage electrode EL2 in the polarization region Lv11 and the second low voltage electrode EL2 in the polarization region Lv12. The low voltage electrode EL2 is electrically connected to each other. The first low voltage electrode EL1 in the polarization region Lv11 and the first low voltage electrode EL1 in the polarization region Lv12, and the second low voltage electrode EL2 in the polarization region Lv11 and the second low voltage electrode EL2 in the polarization region Lv12 Are arranged so as to be electrically connected in a mounted state on a substrate, for example. In addition, in each of the polarization region Lv11 and the polarization region Lv12 of the low voltage portion Lv1, the first low voltage electrode EL1 and the second low voltage electrode EL2 are provided, and the electrical connection is made afterwards. This is because the polarization process can be performed so that the polarization directions are individually opposite to the polarization region Lv11 and the polarization region Lv12.

A first high-voltage electrode EH1 and a second high-voltage electrode EH2 are provided at a pair of lengthwise ends of the piezoelectric body PB.

In the insulated piezoelectric transformer Tr of this embodiment, when the AC voltage V1 is input (applied) between the first high-voltage electrode EH1 and the second high-voltage electrode EH2, the reduced AC voltage V2 is reduced to a low voltage. Between the first low voltage electrode EL1 and the second low voltage electrode EL2 in the polarization region Lv11 of the portion Lv1, and between the first low voltage electrode EL1 and the second low voltage electrode EL2 in the polarization region Lv12. Will be output. In this case, since the polarization region Lv11 and the polarization region Lv12 of the low voltage part Lv1 are adjacent to each other, the expansion state (stress direction) of the polarization region Lv11 and the expansion state (stress direction) of the polarization region Lv12 Conversely, the polarization direction of the polarization region Lv11 and the polarization direction of the polarization region Lv12 are opposite to each other. Therefore, as a result, the phase of the alternating voltage output between the first low-voltage electrode EL1 and the second low-voltage electrode EL2 in the polarization region Lv11 and the first low-voltage electrode EL1 in the polarization region Lv12. And the phase of the AC voltage output between the second low voltage electrode EL2 and the second low voltage electrode EL2.

Here, in the present embodiment, like the first embodiment, the first low voltage electrode EL1 and the second low voltage electrode EL2 are physically connected to the first high voltage electrode EH1 and the second high voltage electrode EH2. Separated floating electrodes. Therefore, as in the first embodiment, it is possible to ensure insulation while suppressing the increase in size of the insulating piezoelectric transformer. Further, since the length of the first high voltage part Hv1 and the length of the second high voltage part Hv2 are equal to each other, the insulation between the input and output can be improved for the same reason as in the first embodiment.

In particular, in the insulation type piezoelectric transformer Tr of the present embodiment, the order n of the longitudinal vibration mode is 4, and the low voltage portion Lv1 is two regions Lv11 arranged along the length direction of the piezoelectric body PB. , Lv12, and the two regions Lv11 and Lv12 each have a length of λ / 2, and the first low voltage electrode EL1 and the second low voltage electrode EL2 include two regions Lv11 and Lv12. Of each. Therefore, it is possible to increase the interelectrode capacitance as the entire low voltage portion Lv1 and increase the output power.

(Embodiment 3)
In the third embodiment, the insulation type piezoelectric transformer Tr is configured using a longitudinal vibration mode of order 5.

FIG. 5 is a diagram illustrating a configuration of the insulating piezoelectric transformer Tr according to the third embodiment.

The insulated piezoelectric transformer Tr of this embodiment includes a piezoelectric body PB having a length of 5λ / 2, a width of less than λ / 2, and a thickness of less than λ / 2, where λ is a wavelength at a resonance frequency.

The low voltage part Lv1 has a polarization region Lv11.

The first high voltage part Hv1 has two polarization regions Hv11 and Hv12 arranged along the length direction of the piezoelectric body PB. The second high voltage unit Hv2 has two polarization regions Hv21 and Hv22 arranged along the length direction of the piezoelectric body PB.

The polarization regions Hv11 and Hv12 of the first high voltage portion Hv1, the polarization region Lv11 of the low voltage portion Lv1, and the polarization regions Hv21 and Hv22 of the second high voltage portion Hv2 each have a length of λ / 2. Accordingly, the lengths of the first high voltage part Hv1 and the second high voltage part Hv2 are λ / 2, which are equal to each other.

The polarization direction of the polarization region Lv11 of the low voltage part Lv1 is a direction parallel to the thickness direction of the piezoelectric body PB.

The polarization directions of the polarization regions Hv11 and Hv12 of the first high voltage portion Hv1 and the polarization regions Hv21 and Hv22 of the second high voltage portion Hv2 are parallel to the length direction of the piezoelectric body PB. Here, the polarization region Hv11 of the first high voltage part Hv1 and the polarization region Hv22 of the second high voltage part Hv2 are the first and fifth from the one end side (left end side) in the length direction of the piezoelectric body PB, respectively. That is, it is an odd-numbered polarization region and is polarized in the same direction. The polarization region Hv12 of the first high-voltage part Hv1 and the polarization region Hv21 of the second high-voltage part Hv2 are the second and fourth, that is, even-numbered polarization regions from the one end side in the length direction of the piezoelectric body PB. Yes, they are polarized in the same direction. However, the polarization region Hv11 of the first high voltage unit Hv1 and the polarization region Hv22 of the second high voltage unit Hv2, and the polarization region Hv12 of the first high voltage unit Hv1 and the polarization region Hv21 of the second high voltage unit Hv2 are odd numbers. Since they are in the relationship between the number and the even number, they are polarized in opposite directions.

A first high-voltage electrode EH1 is provided on one end surface (on the first high voltage portion Hv1 side) in the length direction of the piezoelectric body PB, and the other end (second height in the length direction of the piezoelectric body PB). A second high voltage electrode EH2 is provided on the end face of the voltage part Hv2 side. In the present embodiment, the third high voltage electrode EH3 is provided between the polarization region Hv11 and the polarization region Hv12 of the first high voltage part Hv1, and the polarization region Hv21 and the polarization region of the second high voltage part Hv2 are provided. A fourth high-voltage electrode EH4 is provided between the Hv22. The third high-voltage electrode EH3 is an electrode used when performing polarization treatment on the polarization region Hv11 and the polarization region Hv12 of the first high-voltage part Hv1 when the insulating piezoelectric transformer Tr is manufactured. The fourth high-voltage electrode EH4 is an electrode that is used when performing polarization treatment on the polarization region Hv21 and the polarization region Hv22 of the second high-voltage part Hv2 when the insulating piezoelectric transformer Tr is manufactured.

In the insulated piezoelectric transformer Tr of this embodiment, when an AC voltage is input (applied) between the first high-voltage electrode EH1 and the second high-voltage electrode EH2, the first low-voltage electrode EL1 and Via the second low-voltage electrode EL2 (bypassing the low-voltage part Lv1 (shown as “short through” in FIG. 5)), the electric field in the same direction is applied to the first high-voltage part Hv1 and the second high-voltage part Hv2. Is generated.

Then, on the basis of the same principle as described in the first embodiment, the stepped-down AC voltage V2 is output between the first low voltage electrode EL1 and the second low voltage electrode EL2.

In particular, in the insulation type piezoelectric transformer Tr of the present embodiment, the order n of the longitudinal vibration mode is 5, and the first high voltage portion Hv1 has two regions Hv11 and Hv12 arranged along the length direction. The second high voltage unit Hv2 includes two regions Hv21 and Hv22 arranged along the length direction. The regions Hv11, Hv12, Hv21, and Hv22 each have a length of λ / 2. Thereby, the insulation distance between the first low-voltage electrode EL1 and the second low-voltage electrode EL2 and the first high-voltage electrode EH1 and the second high-voltage electrode EH2 can be increased. Therefore, the insulation performance (withstand voltage) of the insulation type piezoelectric transformer Tr is improved.

(Embodiment 4)
In the fourth embodiment, the insulating piezoelectric transformer Tr is configured using a longitudinal vibration mode of order 6.

FIG. 6 is a diagram illustrating a configuration of an insulating piezoelectric transformer Tr according to the fourth embodiment.

The insulated piezoelectric transformer Tr of this embodiment includes a piezoelectric body PB having a length of 6λ / 2, a width of less than λ / 2, and a thickness of less than λ / 2, where λ is a wavelength at a resonance frequency.

The low voltage part Lv1 has two polarization regions Lv11 and Lv12 arranged along the length direction of the piezoelectric body PB.

The polarization region Hv1 of the first high voltage part Hv1, the polarization regions Lv11 and Lv12 of the low voltage part Lv1, and the polarization regions Hv21 and Hv22 of the second high voltage part Hv2 each have a length of λ / 2. Therefore, the lengths of the first high voltage part Hv1 and the second high voltage part Hv2 are 2λ / 2, which are equal to each other.

The polarization directions of the polarization regions Lv11 and Lv12 of the low voltage part Lv1 are parallel to the thickness direction of the piezoelectric body PB. The polarization region Lv11 is the third or odd-numbered polarization region from one end side (left end side) in the length direction of the piezoelectric body PB, and the polarization region Lv12 is the length direction of the piezoelectric body PB. Since it is the fourth or even-numbered polarization region from one end side, the polarization region Lv11 and the polarization region Lv12 are polarized in opposite directions.

The polarization directions of the polarization regions Hv11 and Hv12 of the first high voltage portion Hv1 and the polarization regions Hv21 and Hv22 of the second high voltage portion Hv2 are parallel to the length direction of the piezoelectric body PB. Here, the polarization region Hv11 of the first high voltage part Hv1 and the polarization region Hv21 of the second high voltage part Hv2 are the first and fifth from the one end side (left end side) in the length direction of the piezoelectric body PB, respectively. That is, it is an odd-numbered polarization region and is polarized in the same direction. The polarization region Hv12 of the first high-voltage part Hv1 and the polarization region Hv22 of the second high-voltage part Hv2 are the second and sixth, that is, even-numbered polarization regions from the one end side in the length direction of the piezoelectric body PB. Yes, they are polarized in the same direction. However, the polarization region Hv11 of the first high voltage unit Hv1 and the polarization region Hv21 of the second high voltage unit Hv2, and the polarization region Hv12 of the first high voltage unit Hv1 and the polarization region Hv22 of the second high voltage unit Hv2 are odd numbers. Since they are in the relationship between the number and the even number, they are polarized in opposite directions.

In the polarization region Lv11 and the polarization region Lv12 of the low voltage portion Lv1, a first low voltage electrode EL1 and a second low voltage electrode EL2 are provided at a pair of ends in the thickness direction of the piezoelectric body PB, respectively. ing. The first low voltage electrode EL1 in the polarization region Lv11 and the first low voltage electrode EL1 in the polarization region Lv12 are electrically connected to each other, and the second low voltage electrode EL2 in the polarization region Lv11 and the second low voltage electrode EL2 in the polarization region Lv12. The low voltage electrode EL2 is electrically connected to each other. The first low voltage electrode EL1 in the polarization region Lv11 and the first low voltage electrode EL1 in the polarization region Lv12, and the second low voltage electrode EL2 in the polarization region Lv11 and the second low voltage electrode EL2 in the polarization region Lv12 Are arranged so as to be electrically connected in a mounted state on a substrate, for example. In addition, in each of the polarization region Lv11 and the polarization region Lv12 of the low voltage portion Lv1, the first low voltage electrode EL1 and the second low voltage electrode EL2 are provided, and the electrical connection is made afterwards. This is because the polarization process can be performed so that the polarization directions are individually opposite to the polarization region Lv11 and the polarization region Lv12.

A first high-voltage electrode EH1 is provided on one end surface (on the first high voltage portion Hv1 side) in the length direction of the piezoelectric body PB, and the other end (second height in the length direction of the piezoelectric body PB). A second high voltage electrode EH2 is provided on the end face of the voltage part Hv2 side. The length of the first high voltage part Hv1 and the length of the second high voltage part Hv2 are 2λ / 2, which are equal to each other. In the present embodiment, the third high voltage electrode EH3 is provided between the polarization region Hv11 and the polarization region Hv12 of the first high voltage portion Hv1, and the polarization region Hv21 and the polarization region of the second high voltage portion Hv2 are provided. A fourth high-voltage electrode EH4 is provided between the Hv22. The third high-voltage electrode EH3 is an electrode used when performing polarization treatment on the polarization region Hv11 and the polarization region Hv12 of the first high-voltage part Hv1 when the insulating piezoelectric transformer Tr is manufactured. The fourth high-voltage electrode EH4 is an electrode used when performing polarization treatment on the polarization region Hv21 and the polarization region Hv22 of the second high-voltage part Hv2 when manufacturing the insulating piezoelectric transformer Tr.

In the insulation-type piezoelectric transformer Tr of the present embodiment, when an AC voltage is input (applied) between the first high-voltage electrode EH1 and the second high-voltage electrode EH2, the first low-voltage electrode EL1. And the second low voltage electrode EL2 (bypassing the low voltage portion Lv1 (shown as “short-circuit penetration” in FIG. 6)), the first high voltage portion Hv1 and the second high voltage portion Hv2 are arranged in the same direction. An electric field is generated.

In the insulated piezoelectric transformer Tr of this embodiment, when the AC voltage V1 is input (applied) between the first high voltage electrode EH1 and the second high voltage electrode EH2, the reduced AC voltage V2 is applied. Are between the first low-voltage electrode EL1 and the second low-voltage electrode EL2 in the polarization region Lv11 of the low-voltage part Lv1, and the first low-voltage electrode EL1 and the second low-voltage electrode in the polarization region Lv12. It is output between EL2. In this case, since the polarization region Lv11 and the polarization region Lv12 are adjacent to each other, the stretched state (stress direction) of the polarization region Lv11 and the stretched state (stress direction) of the polarization region Lv12 are opposite to each other. However, the polarization direction of the polarization region Lv11 and the polarization direction of the polarization region Lv12 are opposite to each other. Therefore, as a result, the phase of the AC voltage output between the first low-voltage electrode EL1 and the second low-voltage electrode EL2 in the polarization region Lv11 and each first low-voltage electrode in the polarization region Lv12 The phase of the AC voltage output between EL1 and the second low-voltage electrode EL2 matches.

Here, in the present embodiment, like the first embodiment, the first low voltage electrode EL1 and the second low voltage electrode EL2 are physically connected to the first high voltage electrode EH1 and the second high voltage electrode EH2. Separated floating electrodes. Therefore, as in the first embodiment, it is possible to ensure insulation while suppressing the increase in size of the insulating piezoelectric transformer. Further, since the length of the first high voltage portion Hv1 and the length of the second high voltage portion Hv2 are equal to each other, the effect that the input / output can be insulated without providing an unpolarized region is obtained as in the first embodiment. .

In particular, in the insulation type piezoelectric transformer Tr of the present embodiment, the order n of the longitudinal vibration mode is 6, and the low voltage portion Lv1 is two regions Lv11 arranged along the length direction of the piezoelectric body PB. , Lv12, and the two regions Lv11 and Lv12 each have a length of λ / 2, and the first low voltage electrode EL1 and the second low voltage electrode EL2 include two regions Lv11 and Lv12. Of each. Therefore, it is possible to increase the interelectrode capacitance as the entire low voltage portion Lv1 and increase the output power.

Further, in the insulation type piezoelectric transformer Tr of the present embodiment, the order n of the longitudinal vibration mode is 6, and the first high voltage portion Hv1 has two regions Hv11 and Hv12 arranged along the length direction. The second high voltage unit Hv2 includes two regions Hv21 and Hv22 arranged along the length direction. The regions Hv11, Hv12, Hv21, and Hv22 each have a length of λ / 2. Thereby, the insulation distance between the first low-voltage electrode EL1 and the second low-voltage electrode EL2 and the first high-voltage electrode EH1 and the second high-voltage electrode EH2 can be increased. Therefore, the insulation performance (withstand voltage) of the insulation type piezoelectric transformer Tr is improved.

(Modification of Embodiment 1)
In the first embodiment, the first high-voltage electrode EH1 and the second high-voltage electrode EH2 are the end portions in the length direction of the piezoelectric body PB (the end surface on the first high-voltage portion Hv1 side and the second high-voltage portion). In the electrode structure of the present embodiment, the first high voltage electrode EH1 and the second high voltage electrode EH2 are the first high voltage portion Hv1 and the second high voltage portion Hv2. Is provided on the side surface.

FIG. 7 is a diagram showing an electrode structure of an insulating piezoelectric transformer Tr according to a modification of the first embodiment. FIG. 7 shows an example in the case of the second high voltage electrode EH2.

In the present modification, the high voltage electrode is formed in a laminated form inside the piezoelectric body PB, and is drawn out and exposed to the side surface of the piezoelectric transformer Tr. Specifically, in the second high-voltage electrode EH2 of the present modification, as shown in FIG. 7, a plurality of sheet-like electrodes EHb are disposed at the end in the length direction of the piezoelectric body PB. Embedded in the width direction at predetermined intervals. Both end portions in the thickness direction of the piezoelectric element body PB in these sheet-like electrodes EHb reach a pair of opposing end faces (side faces) of the piezoelectric element body PB, and these sheet-like electrodes EHb are formed on the side faces. A surface electrode EHa is formed to connect the two end portions.

FIG. 8 is a perspective view of an insulating piezoelectric transformer according to a modification of the first embodiment. That is, FIG. 8 is a perspective view of an insulating piezoelectric transformer obtained by applying the electrode structure shown in FIG. 7 to the insulating piezoelectric transformer of the first embodiment. FIG. 8A shows a state where the surface electrode EHa is not formed, and FIG. 8B shows a state after the surface electrode EHa is formed. As shown in FIGS. 8A, 8B, and 8C, the first high-voltage electrode EH1 and the second high-voltage electrode EH2 are respectively provided at the end portions in the length direction of the piezoelectric body PB. A plurality of sheet-like electrodes EHb are embedded and formed at predetermined intervals in the width direction of the piezoelectric body PB, and surface electrodes EHa are formed on the side surfaces of the portions to connect between both ends of the sheet-like electrodes EHb. ing.

In this modification, the first low-voltage electrode EL1 and the second low-voltage electrode EL2 of the low-voltage part Lv1 also adopt a structure different from that of the first embodiment. Specifically, as shown in FIG. 8D, the first low-voltage electrode EL1 of the low-voltage part Lv1 includes a surface electrode ELa1 formed on the end surface (side surface) in the thickness direction of the piezoelectric body PB, The low voltage portion Lv1 has a plurality of sheet-like electrodes ELb1 embedded and formed at predetermined intervals in the width direction of the piezoelectric body PB and having one end connected to the surface electrode ELa1. The second low voltage electrode EL2 of the low voltage portion Lv1 includes a surface electrode ELa2 formed on an end face (side surface) facing the surface electrode ELa1, and a width direction of the piezoelectric body PB inside the low voltage portion Lv1. And a plurality of sheet-like electrodes ELb2 having one end connected to the surface electrode ELa2. With such a configuration, it is possible to increase the capacity between the first low-voltage electrode EL1 and the second low-voltage electrode EL2 and increase the power that can be extracted.

The surface electrode EHa constituting the first high voltage electrode EH1 and the second high voltage electrode EH2 is formed on the same side surface as the side surface on which the first low voltage electrode EL1 and the second low voltage electrode EL2 are provided. Yes.

(Modification of Embodiment 2)
FIG. 9 is a perspective view of an insulating piezoelectric transformer according to a modification of the second embodiment. 9 is a perspective view of an insulating piezoelectric transformer obtained by applying the electrode structure shown in FIG. 7 to the insulating piezoelectric transformer of the second embodiment. The structures of the first high-voltage electrode EH1, the second high-voltage electrode EH2, the first low-voltage electrode EL1, and the second low-voltage electrode EL2 are the same as in the modification of the first embodiment, and the description thereof is omitted. .

(Modification of Embodiment 3)
FIG. 10 is a perspective view of an insulating piezoelectric transformer according to a modification of the third embodiment. That is, FIG. 10 is a perspective view of an insulating piezoelectric transformer obtained by applying the electrode structure shown in FIG. 7 to the insulating piezoelectric transformer of the third embodiment. The structure of the first high-voltage electrode EH1, the second high-voltage electrode EH2, the first low-voltage electrode EL1, and the second low-voltage electrode EL2 is the same as that of the modification of the first embodiment. The structure of the third high voltage electrode EH3 and the fourth high voltage electrode EH4 is the same as the structure of the first high voltage electrode EH1 (second high voltage electrode EH2).

(Modification of Embodiment 4)
FIG. 11 is a perspective view of an insulating piezoelectric transformer according to a modification of the fourth embodiment. That is, FIG. 11 is a perspective view of an insulating piezoelectric transformer obtained by applying the electrode structure shown in FIG. 7 to the insulating piezoelectric transformer of the fourth embodiment. The structure of the first high-voltage electrode EH1, the second high-voltage electrode EH2, the first low-voltage electrode EL1, and the second low-voltage electrode EL2 is the same as that of the modification of the first embodiment. The structure of the third high voltage electrode EH3 and the fourth high voltage electrode EH4 is the same as the structure of the first high voltage electrode EH1 (second high voltage electrode EH2).

(Mounting example of insulation type piezoelectric transformer of modification of embodiment 3)
FIG. 12 is a diagram illustrating a mounting example of an insulation type piezoelectric transformer according to a modification of the third embodiment illustrated in FIG. 10. In this example, the insulating piezoelectric transformer Tr is connected to the fixed frame B1 via the flexible substrate F1. Specifically, the fixing frame B1 is provided with a mounting hole Bh into which the insulating piezoelectric transformer Tr can be fitted. The flexible substrate F1 is disposed along the longitudinal edge of the attachment hole Bh. The insulated piezoelectric transformer is disposed in the mounting hole Bh of the fixed frame B1, and in this state, the surface electrode EHa and the first low voltage electrode EL1 of the first high voltage electrode EH1 and the second high voltage electrode EH2 As shown in FIG. 13, the surface electrodes ELa1 and ELa2 of the second low-voltage electrode EL2 are respectively joined to the conductive pattern (not shown) formed on the flexible substrate F1 by the solder X1. In place of the solder X1, a conductive adhesive may be used. In addition, the same mounting structure as the mounting example of the insulating piezoelectric transformer of the modification of the third embodiment described above can be applied to the insulating piezoelectric transformer of the modification of the first, second, and fourth embodiments.

(Embodiment 5)
In the first to fourth embodiments, the case where the number of polarization regions constituting the first high voltage part Hv1 is equal to the number of polarization regions constituting the second high voltage part Hv2 has been described. However, the present invention is also applicable when the number of polarization regions constituting the first high voltage part Hv1 is not equal to the number of polarization regions constituting the second high voltage part Hv2. Hereinafter, in Embodiments 5 and 6, the case where the number of polarization regions constituting the first high voltage part Hv1 is not equal to the number of polarization regions constituting the second high voltage part Hv2 will be described.

In the fifth embodiment, the insulation type piezoelectric transformer Tr is configured using a longitudinal vibration mode of order 4.

FIG. 14 is a diagram illustrating a configuration of an insulating piezoelectric transformer Tr according to the fifth embodiment.

The insulated piezoelectric transformer Tr of this embodiment includes a piezoelectric body PB having a length of 4λ / 2, a width of less than λ / 2, and a thickness of less than λ / 2, where λ is a wavelength at a resonance frequency.

The low voltage part Lv1 has one polarization region Lv11.

The first high voltage unit Hv1 has two polarization regions Hv11 and Hv12 arranged along the length direction of the piezoelectric body PB. The second high voltage part Hv2 has one polarization region Hv21.

The polarization regions Hv11 and Hv12 of the first high voltage portion Hv1, the polarization region Lv11 of the low voltage portion Lv1, and the polarization region Hv21 of the second high voltage portion Hv2 each have a length of λ / 2.

The polarization directions of the polarization regions Hv11 and Hv12 of the first high voltage portion Hv1 and the polarization region Hv21 of the second high voltage portion Hv2 are parallel to the length direction of the piezoelectric body PB. Note that the polarization region Hv11 of the first high-voltage part Hv1 is the first, that is, odd-numbered polarization region from one end side (left end side) in the length direction of the piezoelectric body PB. On the other hand, the polarization region Hv12 of the first high voltage part Hv1 and the polarization region Hv21 of the second high voltage part Hv2 are second and fourth from the one end side in the length direction of the piezoelectric body PB, that is, even numbers. This is the polarization region. Therefore, the polarization region Hv12 of the first high voltage part Hv1 and the polarization region Hv21 of the second high voltage part Hv2 are polarized in the same direction. However, these regions and the polarization region Hv11 of the first high voltage part Hv1 are polarized in the opposite directions.

A first high-voltage electrode EH1 and a second high-voltage electrode EH2 are provided at a pair of end portions in the length direction of the piezoelectric body PB. In the present embodiment, the third high voltage electrode EH3 is provided between the polarization region Hv11 and the polarization region Hv12 of the first high voltage unit Hv1. The third high-voltage electrode EH3 is an electrode used when performing polarization treatment on the polarization region Hv11 and the polarization region Hv12 of the first high-voltage part Hv1 when the insulating piezoelectric transformer Tr is manufactured.

In the insulated piezoelectric transformer Tr of the present embodiment, when the AC voltage V1 is input (applied) between the first high voltage electrode EH1 and the second high voltage electrode EH2, the reduced AC voltage V2 is reduced to the first low voltage. The voltage is output between the voltage electrode EL1 and the second low voltage electrode EL2.

Here, in the present embodiment, like the first embodiment, the first low voltage electrode EL1 and the second low voltage electrode EL2 are physically connected to the first high voltage electrode EH1 and the second high voltage electrode EH2. Separated floating electrodes. Therefore, as in the first embodiment, it is possible to ensure insulation while suppressing the increase in size of the insulating piezoelectric transformer.

Since the length of the first high voltage portion Hv1 and the length of the second high voltage portion Hv2 are different, the first low voltage electrode EL1 and the second low voltage electrode EL2 are different from the first to fourth embodiments. In this case, a fluctuation due to a high voltage component input between the first high voltage electrode EH1 and the second high voltage electrode EH2 appears. However, the high voltage component appearing on the first low voltage electrode EL1 and the high voltage component appearing on the second low voltage electrode EL2 have the same magnitude. Therefore, a potential difference due to the high voltage component does not occur between the first low voltage electrode EL1 and the second low voltage electrode EL2, and only the voltage generated by the piezoelectric effect in the polarization region Lv11 of the low voltage portion Lv1 is the first voltage. The signal is output from between the first low voltage electrode EL1 and the second low voltage electrode EL2.

(Embodiment 6)
In the sixth embodiment, the insulating piezoelectric transformer Tr is configured using a longitudinal vibration mode of order 7.

FIG. 15 is a diagram illustrating a configuration of an insulating piezoelectric transformer Tr according to the sixth embodiment.

The insulated piezoelectric transformer Tr of this embodiment includes a piezoelectric body PB having a length of 7λ / 2, a width of less than λ / 2, and a thickness of less than λ / 2, where λ is a wavelength at a resonance frequency.

The piezoelectric element body PB is formed using piezoelectric ceramics. The piezoelectric body PB has a first high voltage part Hv1, a low voltage part Lv1, and a second high voltage part Hv2 in this order along the length direction.

The low voltage portion Lv1 has three polarization regions Lv11, Lv12, and Lv13 arranged along the length direction of the piezoelectric body PB.

The first high voltage part Hv1 has three polarization regions Hv11, Hv12, and Hv13 arranged along the length direction of the piezoelectric body PB. The second high voltage part Hv2 has one polarization region Hv21.

The polarization regions Hv11, Hv12, Hv13 of the first high voltage portion Hv1, the polarization regions Lv11, Lv12, Lv13 of the low voltage portion Lv1, and the polarization region Hv21 of the second high voltage portion Hv2 each have a length of λ / 2. .

The polarization direction of the polarization regions Lv11, Lv12, Lv13 of the low voltage part Lv1 is a direction parallel to the thickness direction of the piezoelectric body PB. The polarization regions Lv11 and Lv13 are the fourth and sixth, that is, even-numbered polarization regions from one end side (left end side) in the length direction of the piezoelectric body PB, and the polarization region Lv12 is the piezoelectric body PB. The fifth or odd-numbered polarization region from the one end side in the length direction. For this reason, the polarization region Lv11 and the polarization region Lv13 are polarized in the same direction, but the polarization region Lv12 is polarized in the opposite direction.

The polarization directions of the polarization regions Hv11, Hv12, Hv13 of the first high voltage part Hv1 and the polarization region Hv21 of the second high voltage part Hv2 are parallel to the length direction of the piezoelectric body PB. The polarization regions Hv11 and Hv13 of the first high voltage part Hv1 and the polarization region Hv21 of the second high voltage part Hv2 are first to third from the one end side (left end side) in the length direction of the piezoelectric body PB. And the seventh, that is, odd-numbered polarization region. On the other hand, the polarization region Hv12 of the first high voltage part Hv1 is the second, ie, even-numbered polarization region from the one end side in the length direction of the piezoelectric body PB. Therefore, although the polarization region Hv11, the polarization region Hv13, and the polarization region Hv21 of the second high voltage portion Hv2 of the first high voltage portion Hv1 are polarized in the same direction, these regions and the first high voltage portion Hv1 The polarization region Hv12 is polarized in the opposite direction.

In the polarization region Lv11, the polarization region Lv12, and the polarization region Lv13 of the low voltage portion Lv1, a pair of ends in the thickness direction of the piezoelectric body PB are respectively provided with a first low voltage electrode EL1 and a second low voltage electrode. An electrode EL2 is provided.

A first high-voltage electrode EH1 and a second high-voltage electrode EH2 are provided at a pair of end portions in the length direction of the piezoelectric body PB. In the present embodiment, the third high voltage electrode EH3 and the fourth high voltage electrode are provided between the polarization region Hv11 and the polarization region Hv12 of the first high voltage unit Hv1 and between the polarization region Hv12 and the polarization region Hv13. An electrode EH4 is provided. The third high voltage electrode EH3 and the fourth high voltage electrode EH4 are used to polarize the polarization region Hv11, the polarization region Hv12, and the polarization region Hv13 of the first high voltage portion Hv1 when the insulating piezoelectric transformer Tr is manufactured. It is an electrode used when performing.

In the insulated piezoelectric transformer Tr of this embodiment, when the AC voltage V1 is input (applied) between the first high voltage electrode EH1 and the second high voltage electrode EH2, the reduced AC voltage V2 is applied. Are between the first low-voltage electrode EL1 and the second low-voltage electrode EL2 in the polarization region Lv11 of the low-voltage part Lv1, and between the first low-voltage electrode EL1 and the second low-voltage electrode EL2 in the polarization region Lv12. And between the first low voltage electrode EL1 and the second low voltage electrode EL2 in the polarization region Lv13. At this time, for the same reason as described in the second embodiment, the phase of the AC voltage output between the first low voltage electrode EL1 and the second low voltage electrode EL2 in the polarization region Lv11, and the polarization region The phase of the alternating voltage output between each first low voltage electrode EL1 and second low voltage electrode EL2 of Lv12, and each first low voltage electrode EL1 and second low voltage electrode of polarization region Lv13 The phase of the alternating voltage output between EL2 will be in agreement.

Although the length of the first high voltage portion Hv1 and the length of the second high voltage portion Hv2 are different, as described in the fifth embodiment, the first low voltage electrode EL1 and the second low voltage electrode EL2 are used. Between the first low-voltage electrode EL1 and the second low-voltage electrode EL2, only the voltage generated by the piezoelectric effect in the polarization region Lv11 of the low-voltage portion Lv1 does not occur. Will be output.

(Other embodiments)
In each of the above embodiments, the case where the insulating piezoelectric transformer Tr is configured using the longitudinal vibration mode of the order 3 to 7 has been described. However, the technical idea of the present invention can also be applied when the order is 8 or more. In each of the above embodiments, the case where the low voltage unit, the first high voltage unit, and the second high voltage unit have only one region or two regions has been described. However, each of the low voltage part, the first high voltage part, and the second high voltage part may have three or more regions. In this case, each of the plurality of regions has a length of λ / 2, and the polarization direction of each region may be set based on the above-described concept of setting the polarization direction.

In each of the above embodiments, the case where the insulating piezoelectric transformer Tr is used as a step-down transformer has been described. However, the insulating piezoelectric transformer Tr of each embodiment according to the present invention can also be used as a step-up transformer. That is, an AC voltage is input between the first low voltage electrode EL1 and the second low voltage electrode EL2, and the AC voltage is boosted from between the first high voltage electrode EH1 and the second high voltage electrode EH2. Output voltage. Insulating piezoelectric transformers Tr according to the embodiments of the present invention, for example, make the interelectrode capacitance of a pair of low voltage electrodes equal to the interelectrode capacitance of a pair of high voltage electrodes without transforming the voltage. It can be configured as an insulating transformer that can be insulated. That is, the insulation type piezoelectric transformer according to the present invention can be configured as a transformer for the purpose of insulation only.
That is,
In the insulated piezoelectric transformer of the present invention,
The interelectrode capacity of the pair of low voltage electrodes and the interelectrode capacity of the pair of high voltage electrodes are set equal,
When an AC voltage is input between any one of the pair of low voltage electrodes and between the pair of high voltage electrodes, the AC voltage input between the one electrode and the other electrode. AC voltage of the same magnitude as is output.

FIG. 16 shows an example in which the step-up transformer of this embodiment is applied to the power transmission device 100 of the electric field coupling type wireless power transmission device. In the power transmission device 100 of FIG. 16, the AC voltage generated by the power transmission circuit 110 is boosted by the step-up transformer Tr1 and applied between the pair of power transmission electrodes Eta and Etp. As shown in FIG. 16, by using a piezoelectric transformer as a step-up transformer, the power transmission device 100 can be made smaller than when a winding transformer is used.

In each of the above embodiments, the case where the insulating piezoelectric transformer of the present invention is applied to an electric field coupling type wireless power transmission system has been described. However, the insulating piezoelectric transformer of the present invention is also applied to a power receiving device and a power transmitting device of a magnetic power coupling type (electromagnetic coupling type, magnetic coupling type) or magnetic field resonance type (electromagnetic resonance type, magnetic resonance type) wireless power transmission system. Is possible. That is, the power transmission electrode in the present invention is a power transmission coil (inductor), and the power reception electrode in the present invention is a power reception coil (inductor). The power transmission coil is connected to the high voltage electrode of the insulation type piezoelectric transformer. More specifically, the power transmission coil is connected between a pair of high voltage electrodes of an insulating piezoelectric transformer. The power receiving coil is connected to the high voltage electrode of the insulating piezoelectric transformer. More specifically, the power receiving coil is connected between a pair of high voltage electrodes of an insulating piezoelectric transformer. As a result, the power receiving device and power transmitting device of the magnetic field coupling type and magnetic field resonance type wireless power transmission system can be reduced in size and height.

The insulated piezoelectric transformer according to the present invention can be widely used in various electronic devices and electrical devices.

DESCRIPTION OF SYMBOLS 100 Power transmission apparatus 200 Power receiving apparatus 110 Power transmission circuit 210 Load circuit B1 Fixed frame Bh Mounting hole Era Power receiving electrode (Power receiving side active electrode)
Erp power receiving electrode (power-receiving-side passive electrode)
Eta power transmission electrode (power transmission side active electrode)
Etp power transmission electrode (power transmission side passive electrode)
EL1 first low voltage electrode EL2 second low voltage electrode EH1 first high voltage electrode EH2 second high voltage electrode EH3 third high voltage electrode EH4 fourth high voltage electrode F1 flexible substrate Hv1 first high voltage Part Hv11 Polarization region Hv12 Polarization region Hv13 Polarization region Hv2 Second high voltage part Hv21 Polarization region Hv22 Polarization region Lv1 Low voltage part Lv11 Polarization region Lv12 Polarization region Lv13 Polarization region PB Piezoelectric element Tr Step-down transformer (insulating piezoelectric transformer)
X1 solder

Claims

An insulating piezoelectric transformer using a longitudinal vibration mode of order n (n is an integer of 3 or more),
Provided with a piezoelectric body having a length of nλ / 2, where λ is the wavelength at the resonance frequency,
The piezoelectric body has a first high voltage part, a low voltage part, and a second high voltage part in order along the length direction,
The low voltage part has an integer number of polarization regions having a length of λ / 2 along the length direction of the piezoelectric body.
Each of the first high voltage part and the second high voltage part has an integral number of polarization regions having a length of λ / 2 along the length direction of the piezoelectric element body,
The polarization direction of the polarization region constituting the low voltage part is:
Parallel to the thickness direction of the piezoelectric body,
And when the number of polarization regions constituting the low-voltage part is 2 or more, the odd-numbered and even-numbered ones from one end side in the length direction of the piezoelectric element body are set to be in the same direction, In addition, the odd-numbered polarization region and the even-numbered polarization region are set to be in opposite directions,
The polarization directions of the polarization regions constituting the first high voltage part and the second high voltage part are:
Parallel to the length direction of the piezoelectric body,
And the odd-numbered and even-numbered ones are set to be in the same direction from one end side in the length direction of the piezoelectric body, and the odd-numbered and even-numbered polarized regions are in opposite directions. Is set to
Low voltage electrodes are respectively provided at a pair of end portions in the thickness direction of the piezoelectric body of the low voltage portion,
High-voltage electrodes are respectively provided at a pair of end portions in the length direction of the piezoelectric body,
The low voltage electrode and the high voltage electrode are physically separated,
Insulation type piezoelectric transformer.
The number of polarization regions constituting the first high voltage part and the number of polarization regions constituting the second high voltage part are the same,
The length of the first high voltage part is equal to the length of the second high voltage part,
The insulated piezoelectric transformer according to claim 1.
An AC voltage is input to the high voltage electrode, and an AC voltage stepped down from the low voltage electrode is output.
The insulated piezoelectric transformer according to claim 1 or 2.
An AC voltage is input to the low voltage electrode, and a boosted AC voltage is output from the high voltage electrode.
The insulated piezoelectric transformer according to claim 1 or 2.
The piezoelectric body has a width of less than λ / 2 and a thickness of less than λ / 2.
The insulation type piezoelectric transformer according to any one of claims 1 to 4.
An insulating piezoelectric transformer according to claim 4,
A receiving electrode is connected to the high voltage electrode of the insulating piezoelectric transformer,
An input of a power receiving circuit is connected to the low voltage electrode of the insulation type piezoelectric transformer.
A power receiving device for a wireless power transmission system.
An insulating piezoelectric transformer according to claim 5 is provided,
An output of a power transmission circuit is connected to the low voltage electrode of the insulation type piezoelectric transformer,
A power transmission electrode is connected to the high voltage electrode of the insulating piezoelectric transformer.
A power transmission device for a wireless power transmission system.