WO1999034454A1

WO1999034454A1 - Piezoelectric transformer

Info

Publication number: WO1999034454A1
Application number: PCT/JP1998/005891
Authority: WO
Inventors: Mitsunobu Yoshida; Kouichi Kanayama; Nobuhiro Maruko; Hiroaki Saigoh
Original assignee: Mitsui Chemicals, Inc.
Priority date: 1997-12-26
Filing date: 1998-12-25
Publication date: 1999-07-08

Abstract

Square electrodes (1-9) are formed on the front surface of a piezoelectric ceramic plate (100) like a grid having 3x3 regions, and square electrodes (10-18) are formed on the back surface like a grid having 3x3 regions. The portions between corresponding electrodes are polarized in the direction (z direction) vertical to the major surfaces of the plate (100) and in the direction parallel with the plate (100) to divide the plate (100) which is square when viewed from above into three regions in the x direction and three regions in the y direction, that is, into a total of nine (3x3) regions (101-109). A pair of electrodes (5, 14) provided for the front and back surfaces of the central region (105) is used as one electrode for excitation and one electrode for output, respectively; and a pair of electrodes (1, 10), a pair of electrodes (3, 12), a pair of electrodes (7, 16), and a pair of electrodes (9, 18) are used as the other electrodes for excitation and the other electrodes for output, respectively. Thus, it is possible to realize a piezoelectric transformer whose output is high, whose efficiency is high, whose manufacturing cost is low, whose size is small, and which has a high degree of freedom of selection of the transformation ratio.

Description

Description Piezoelectric transformer Technical field

TECHNICAL FIELD The present invention relates to a piezoelectric transformer.

In recent years, piezoelectric transformers have been used for transformers, taking advantage of their high efficiency, small size, non-combustibility, and low noise compared to electromagnetic transformers. The main applications are lighting applications (for discharge tube lighting), air purifiers, and ozone generators. It is also used in step-down applications such as switching power supplies and AC adapters.

Conventionally, this type of piezoelectric transformer has a configuration as shown in FIGS.

FIG. 47 is a perspective view showing a conventional Rosen-type piezoelectric transformer. This piezoelectric transformer 600 is composed of a left primary region 620 and a right secondary region 630. In the primary region 620, primary electrodes 612 are provided on upper and lower surfaces of the piezoelectric substrate 610, respectively, and the piezoelectric substrate 610 is polarized in the thickness direction. In the secondary electrode 630, a secondary electrode 614 is provided at the right end on the upper surface of the piezoelectric substrate 610, and the piezoelectric substrate 610 is polarized in the longitudinal direction. The AC voltage supplied from the power supply 80 between the primary electrodes is boosted by the piezoelectric transformer 600, extracted from the secondary electrodes 614, and applied to the load 91.

In recent years, a piezoelectric transformer having a structure corresponding to a step-down application for a switching power supply has also been announced. An example is shown below. FIG. 48 is a perspective view showing a conventional (piezoelectric lateral effect—piezoelectric lateral effect) step-down piezoelectric transformer 700, in which a primary region in which a plurality of layers are stacked in the thickness direction of the piezoelectric substrate 7100. 7 and a secondary region 730 in which a plurality of layers are stacked in the thickness direction.

FIG. 49 is a perspective view showing a conventional (piezoelectric longitudinal effect-piezoelectric longitudinal effect) step-down piezoelectric transformer 800, in which a primary side region 8 in which a plurality of layers are laminated in the longitudinal direction of the piezoelectric substrate 8100. 20 and a secondary region 830 in which a plurality of layers are stacked in the longitudinal direction.

The present invention seeks to solve two problems.

The first point is that it is difficult to increase the output with a conventional boosting piezoelectric transformer structure such as the Rosen type piezoelectric transformer shown in Fig. 47. Generally, it is considered effective to increase the mass of the piezoelectric vibrator by increasing the volume of the piezoelectric vibrator as an effective measure when increasing the output power while maintaining high efficiency. Because, when the mechanical vibration speed is constant, the larger the mass of the piezoelectric vibrator, the larger the mechanical vibration energy stored inside the vibrator, and as a result, it can be extracted from the output electrode by the piezoelectric effect This is because the energy increases.

To increase the mass of the Rosen-type piezoelectric transformer shown in Fig. 47, it is conceivable to change the thickness, width, and length, but these have the following problems.

The problem with increasing the thickness is that the input impedance first increases, which results in a lower boost ratio. Also, it is difficult to reduce the thickness due to the increase in thickness. In addition, the heat dissipation area per unit volume is reduced because the thickness is increased, and the heat dissipation effect is reduced.

The problem with extending the longitudinal direction is that if the longitudinal direction is The frequency must be lowered, and it is difficult to set a desired driving frequency.

The problem with stretching in the width direction is that the greater the width, the greater the proportion of mechanical vibration energy that propagates in the width direction, and the more energy that propagates in the longitudinal direction cannot be obtained.

The second point is that the step-down type piezoelectric transformer for switching power supply as shown in Fig. 48 and Fig. 49 has a large number of stacked layers, which lowers the efficiency, and the large number of stacked layers increases the manufacturing cost. . In the structure shown in Fig. 48 and Fig. 49, the ratio of input / output impedance cannot be changed with a single board, so that the structure is multi-layered and the ratio of the number of layers on the input side to the number of layers on the output side is changed. It is necessary to obtain a boost ratio. However, when the number of layers is increased, there is a problem that energy conversion efficiency is reduced while manufacturing costs are increased.

The present invention is intended to solve the above two problems. When used as a step-up transformer, the output power can be increased, and when used as a step-down piezoelectric transformer, a large electric power can be obtained. An object of the present invention is to provide a piezoelectric transformer that can achieve cost reduction, cost reduction, high efficiency, and thinness. Disclosure of the invention

Means for Solving the Problems In order to achieve the above object, the present inventors have earnestly studied and obtained the following findings.

That is, a piezoelectric body such as a flat plate made of piezoelectric ceramics is divided into a plurality of lattice-shaped regions, electrodes are provided in each region, each region is polarized, and at least one of the plurality of regions is subjected to the piezoelectric treatment. We have found that the following actions and effects can be obtained by using a piezoelectric transformer that is configured as a body excitation area and at least one of the remaining areas is an output area. One is to increase the output. Increasing the mass of the vibrator is effective in increasing power consumption. In this piezoelectric transformer, by using high-order piezoelectric resonance vibration without changing the vibration frequency, it is possible to increase the element length in two directions, the longitudinal direction or the width direction. . In other words, it has a structure that can easily handle high power consumption. Next, because of the flat plate structure, the heat radiation area per unit area is large. As a result, the structure has a large heat dissipation effect and is advantageous for increasing output.

The second is cost reduction. Even if this piezoelectric transformer has a single-plate structure, a large transformer ratio can be obtained by increasing the number of regions that divide the flat plate. Therefore, to obtain a large transformation ratio, the number of stacked layers is smaller than that of a conventional piezoelectric transformer. As a result, manufacturing costs can be significantly reduced.

The third is higher efficiency. This piezoelectric transformer requires a smaller number of layers to obtain the required transformation ratio than conventional piezoelectric transformers. Therefore, mechanical loss at the interface of the laminated board is reduced, and higher efficiency can be expected. Also, since the electrode take-out part can be provided at the node of the vibration, there is little mechanical loss in piezoelectric vibration, and high efficiency can be expected.

The fourth is thinning. Since this piezoelectric transformer has a flat plate structure and can expand the vertical and horizontal areas, it can be thinner when compared with the conventional piezoelectric transformer when compared with the same volume.

Fifth, there is a high degree of freedom in selecting the transformation ratio. When a flat plate is divided into a grid of m X n areas, the number of excitation areas can be selected from 1 to (m X n-1). Has (m X n -1) to 1 degree of freedom of choice. Similarly, when using one input and multiple outputs, the degree of freedom in selecting the number of regions is large.

Sixth, it can be used as a single-input multiple-output transformer. For example, in the case of a piezoelectric transformer with a 3x3 area, one area or Two or more regions are connected in parallel as an input region, one region or two or more regions are connected in parallel as a first output region, and another one region or another two or more By connecting the areas in parallel, it becomes possible to operate as a 1-input 2-output piezoelectric transformer as a second output area. By this analogy, a one-input three-output piezoelectric transformer can be easily configured.

A piezoelectric transformer in which a flat plate made of a piezoelectric material is divided into a total of m × n lattice-shaped regions in a first direction (for example, in the longitudinal direction) and in a second direction (for example, in the width direction), and The flat plate can be operated by exciting a standing wave due to piezoelectric resonance vibration. By applying an AC voltage waveform having a frequency such that an adjacent region performs piezoelectric vibration of the opposite phase to the excitation electrode provided in an area of the flat plate, an inverse piezoelectric transverse effect is generated on the flat plate, It operates by exciting a standing wave of mechanical vibration due to piezoelectric resonance of m / 2 wavelength in the longitudinal direction and n / 2 wavelength in the width direction in the plane. When operated in this manner, for example, a state as shown in FIG. 5 is obtained. 5A, 5B, and 5C are plan views showing an example of a stretched state of a flat plate divided into 3 × 3, and FIG. 5D is a view showing a stress distribution in the state of FIG. Fig. 5E is a diagram showing the displacement distribution in the state of Fig. 5A, Fig. 5F is a diagram showing the stress distribution in the state of Fig. 5C, and Fig. 5G is the displacement distribution in the state of Fig. 5C. FIG. When an AC voltage waveform having the above frequency is applied to the excitation electrode, the length of the grid-divided region in the first direction (for example, the longitudinal direction) and the length in the second direction (for example, the width direction) By setting the ratio to 0.7 to 1.3, and preferably 1, the mechanical vibration energy generated by the piezoelectric effect in the excitation electrode portion is evenly transmitted in the first direction and the second direction. Equalization of the transmitted energy also reduces stress concentrations and allows for higher power limits.

In addition, the number m and n of the areas divided in a grid are equal, and the first direction When the length in the longitudinal direction (for example, the longitudinal direction) is equal to the length in the second direction (for example, the width direction), the shape of the piezoelectric transformer is a square. At this time, by disposing the excitation electrode or the output electrode in the central area and disposing the output electrode or the excitation electrode in the peripheral area respectively, the energy propagation is evenly propagated in all directions. . As a result, stress concentration is reduced, and the limit value of usable power can be increased.

Further, not only when the shape of the piezoelectric transformer is square, but also in a more general shape, the excitation electrode or the output electrode is arranged in the center area, and the output electrode or the excitation electrode is arranged in the peripheral area. By arranging the electrodes, the cross-sectional area where the mechanical resonance energy propagates can be taken in all directions. For this reason, it is possible to reduce the density of the mechanical resonance energy passing per unit area, and as a result, it is possible to further increase the limit value of the usable power.

In the piezoelectric transformer of the present invention, the mechanical vibration energy of the flat plate can be converted into AC electric energy by a piezoelectric transverse effect or a piezoelectric longitudinal effect, and can be extracted from the output electrode.

Then, input / output voltage conversion can be performed based on the ratio of the impedance Zin of the excitation electrode to the impedance Zout of the output electrode. Therefore, by changing the combination of the number of excitation areas and the number of output areas and changing the combination of the number of excitation electrodes and the number of output electrodes, it is possible to increase the degree of freedom in selecting the transformation ratio. For example, the input impedance and output impedance can be matched, and operation can be performed with a transformation ratio of 1. Also, if the input impedance is smaller than the output impedance, it will operate at a transformer ratio of 1 or more. That is, it operates as a step-up transformer. In addition, the input impedance can be made larger than the output impedance, and the operation can be performed with a transformation ratio of 1 or less. That is, as a step-down transformer Works. The present invention is based on the above findings, and according to a first aspect of the present invention, comprises two main surfaces facing each other and substantially parallel to each other, and m (m is (N is an integer greater than or equal to 2) Section, divided into a grid of n (n is an integer of 2 or more) sections in the second direction in the main surface and intersecting with the first direction in the second direction A piezoelectric transformer including a piezoelectric body having a plurality of regions,

At least one of the plurality of regions is an excitation region to which excitation power for exciting the piezoelectric body is supplied,

A first piezoelectric transformer is provided, wherein at least one other of the remaining regions of the plurality of regions is an output region for extracting an output from the piezoelectric transformer. According to a second aspect of the present invention, in the first piezoelectric transformer,

The piezoelectric body is a flat plate,

A second piezoelectric transformer is provided in which an excitation electrode pair is provided on the two main surfaces in the excitation region, and an output electrode pair is provided on the two main surfaces in the output region. . According to a third aspect of the present invention, in the first piezoelectric transformer,

In the excitation area, an excitation electrode pair facing each other is provided substantially parallel to the two main surfaces,

In the output area, the output electrode pairs facing each other have the two main surfaces. Is provided substantially in parallel with,

One of the excitation electrode pairs is provided on one of the two main surfaces or inside the piezoelectric body,

The other of the excitation electrode pair is provided on the other main surface of the two main surfaces or inside the piezoelectric body,

One of the output electrode pairs is provided on one of the two main surfaces or inside the piezoelectric body,

A third piezoelectric transformer is provided in which the other of the pair of output electrodes is provided on the other main surface of the two main surfaces or inside the piezoelectric body. According to a fourth aspect of the present invention, in the third piezoelectric transformer,

The piezoelectric body is configured by laminating a plurality of flat plates made of a piezoelectric material, and the plurality of flat plates each include two sub-main surfaces substantially parallel to the two main surfaces,

The plurality of flat plates each have a plurality of sub-regions divided into the m sections in the first direction and the n sections in the second direction in a grid shape, and the one of the excitation electrode pairs is A plurality of sub-main surfaces of the plurality of sub-regions stacked in the excitation region are provided on at least one sub-main surface;

The other of the excitation electrode pairs is provided on at least one of the remaining sub-main surfaces of the plurality of sub-main surfaces;

The one and the other of the output electrode pairs are respectively provided on any two of the plurality of sub-main surfaces of the plurality of sub-regions stacked in the output region. Is provided with a fourth piezoelectric transformer W

You.

In the fourth piezoelectric transformer, preferably, at least one electrode pair in an area divided into a lattice on the upper surface of the uppermost layer and the lower surface of the lowermost layer in the laminated plate of the piezoelectric transformer is used as an excitation electrode pair. At least one electrode pair among the electrode pairs between the layers sandwiched between the uppermost layer and the lowermost layer is used as the output electrode.

In the fourth piezoelectric transformer, preferably, at least one pair of electrodes in an area divided into a grid between the upper surface of the uppermost layer and the lower surface of the lowermost layer is preferably used as the output electrode. At least one electrode pair among the electrode pairs between the layers sandwiched between the uppermost layer and the lowermost layer is used as an excitation electrode.

Further, in the above-described piezoelectric transformer formed of a laminated plate, preferably, the excitation electrode section and the output electrode section are not arranged in the same layer or in the same plane.

By doing so, the insulation between the excitation electrode and the output electrode can be improved, the dielectric strength between the input and output can be significantly improved, and the electrical independence between the commercial AC power supply and the equipment can be improved. It is possible to increase. According to a fifth aspect of the present invention, in any one of the second to fourth piezoelectric transformers,

A fifth piezoelectric transformer is provided, wherein the piezoelectric body between the excitation electrode pair and the piezoelectric body between the output electrode pair are polarized in a direction substantially perpendicular to the two main surfaces. In the first piezoelectric transformer, preferably,

The piezoelectric transformers are substantially parallel to the two main surfaces and An excitation electrode pair provided to face each other, and an output electrode pair substantially parallel to the two main surfaces and provided to face each other,

One of the excitation electrode pairs is on one of the two main surfaces of the piezoelectric body in the excitation region, and on the one main surface of the piezoelectric body in the excitation region. When a first additional piezoelectric body is provided, on the first additional piezoelectric body, or inside the piezoelectric body in the excitation region,

The other one of the excitation electrode pairs is formed on the other of the two main surfaces of the piezoelectric body in the excitation region 、, and on the other main surface of the piezoelectric body in the excitation region 第When an additional piezoelectric body is provided, the piezoelectric body is provided on the second additional piezoelectric body or inside the piezoelectric body in the excitation recording area,

One of the output electrode pairs is on one of the two main surfaces of the piezoelectric body in the output region, and is on the one main surface of the piezoelectric body in the output region. When a third additional piezoelectric body is provided, the third additional piezoelectric body is provided on the third additional piezoelectric body or inside the piezoelectric body in the output area.

The other of the pair of output electrodes is provided on the other of the two main surfaces of the piezoelectric body in the output region, and on the other main surface of the piezoelectric body in the output region, When the additional piezoelectric body is provided, the piezoelectric body is provided on the fourth additional piezoelectric body or inside the piezoelectric body in the output area.

In this case, preferably,

The one and the other of the excitation electrode pair are provided on the two main surfaces in the excitation region, respectively, and the one and the other of the output electrode pair are in the output region. A force provided inside the piezoelectric body, Or

The one and the other of the excitation electrode pair are provided inside the piezoelectric body in the excitation region, and the one and the other of the output electrode pair are the two in the output region. Each is provided on the main surface.

With this structure, the insulation distance between the excitation electrode and the output electrode is increased, and as a result, the dielectric strength between the excitation electrode and the output electrode is greatly increased.

Preferably, each of the regions of each of the above piezoelectric transformers is polarized in a direction substantially perpendicular to the two main surfaces. According to a sixth aspect of the present invention, in the first piezoelectric transformer,

A first electrode and a second electrode that are one of an excitation electrode and an output electrode are respectively provided on the two main surfaces in one of the excitation region and the output region;

A third electrode that is the other of the excitation electrode and the output electrode is provided on at least one of the two main surfaces in the other of the excitation area and the output area;

The piezoelectric body between the first electrode and the second electrode is polarized substantially perpendicular to the two main surfaces;

At least a part of the piezoelectric body in the other area of the excitation area and the output area is polarized so as to have a polarization component parallel to the two main surfaces. Six piezoelectric transformers are provided. According to a seventh aspect of the present invention, in the first piezoelectric transformer, In one of the excitation area and the output area, a first electrode and a second electrode that are one of the excitation electrode and the output electrode face each other and are substantially on the two main surfaces. A third electrode serving as the other of the excitation electrode and the output electrode is provided in the other of the excitation area and the output area. One of the electrodes is located on one of the two main surfaces in the one of the excitation area and the output area or the excitation area and the output area. Provided inside the piezoelectric body in one region,

The second electrode is provided on the other of the two main surfaces in the one of the excitation area and the output area, or the one of the excitation area and the output area. Is provided inside the piezoelectric body in the region of

A seventh piezoelectric transformer is provided in which at least a part of the other area of the excitation area and the output area is polarized so as to have a polarization component parallel to the two main surfaces. Is done.

With this structure, the insulation between the excitation electrode and the output electrode can be improved, the dielectric strength between the input and output can be significantly improved, and the electrical independence between the commercial AC power supply and the equipment can be improved. It is possible to increase.

In the seventh or eighth piezoelectric transformer, preferably, at least a part of the other area of the excitation area and the output area is any one of the first and second electrodes. It is polarized substantially along the direction connecting one of the electrodes and the third electrode.

In the seventh piezoelectric transformer, preferably, The seventh piezoelectric transformer is a fourth electrode provided on at least one of the two main surfaces in the other region of the excitation region and the output region, wherein: And a fourth electrode provided apart from the third electrode when viewed in a plan view from a direction perpendicular to the third electrode, wherein the fourth electrode is provided in the other of the excitation area and the output area. At least a part thereof is polarized substantially along the direction connecting the third electrode and the fourth electrode.

In the seventh piezoelectric transformer, preferably,

A fourth electrode provided in the other one of the excitation area and the output area, wherein the fourth electrode and the third electrode are viewed in a plan view from a direction perpendicular to the main surface. Further comprising the fourth electrode provided at a distance, wherein at least a part of the other area of the excitation area and the output area is the third electrode and the fourth electrode The polarization is substantially along the direction connecting.

Also preferably,

An outer shape of one of the third and fourth electrodes is substantially circular when viewed in a plan view from a direction perpendicular to the main surface;

The other inner shape of the third and fourth electrodes is substantially circular in plan view from a direction perpendicular to the main surface,

The one of the third and fourth electrodes is provided inside the other of the third and fourth electrodes,

The substantially circular shape outside the one of the third and fourth electrodes and the substantially circular shape inside the other of the third and fourth electrodes are substantially concentrically arranged.

With this structure, the electric field intensity during polarization becomes more uniform, and more uniform polarization becomes possible. According to an eighth aspect of the present invention, in the seventh piezoelectric transformer,

The plurality of flat plates each have a plurality of sub-regions divided in a grid shape of the m sections in the first direction and the n sections in the second direction, and the first electrode includes the excitation electrode. A plurality of sub-main surfaces of the plurality of sub-regions stacked in the one of the output region and the output region are provided on at least one of the sub-main surfaces,

The second electrode is provided on at least one sub-main surface of the remaining sub-main surfaces of the plurality of sub-main surfaces;

The third electrode may be any one of the plurality of sub-main surfaces of the plurality of sub-regions stacked in the other region of the excitation region and the output region. An eighth piezoelectric transformer provided on the main surface is provided.

Preferably, in a piezoelectric transformer in which a plurality of piezoelectric layers are stacked, the excitation electrode and the output electrode are not arranged in the same piezoelectric layer or in the same plane.

Preferably, the shape of the third electrode is substantially circular when viewed in a plan view from a direction perpendicular to the main surface.

In this way, by making the shape of the electrode approximately circular in plan view, the electric field intensity around the electrode during polarization tends to be uniform, and uniform polarization processing can be performed. According to a ninth aspect of the present invention, in the first piezoelectric transformer,

At least a portion of one of the excitation region and the output region is polarized substantially perpendicular to the two main surfaces;

A ninth piezoelectric transformer is provided in which at least a part of the other of the excitation area and the output area is polarized so as to have a polarization component parallel to the two main surfaces.

As described above, one of the input side (excitation side) and the output side is a region having a component whose polarization is in the plane, that is, a region polarized so as to have a polarization component parallel to the main surface of the flat plate. By setting the other side to the thickness direction on the other side, the ratio between the input impedance and the output impedance can be increased, and as a result, the boost ratio or the buck ratio can be increased. . In each of the above piezoelectric transformers, preferably,

The coordinates of the area at any one corner of the grid among the plurality of areas arranged in the grid shape are both set to 1 in the first and second directions, and from the area at any one corner, The coordinate of the area of the p-th surface along the first direction in the first direction is P, and the coordinate of the area of the q-th surface along the second direction from the one corner area along the second direction. If the coordinate in the direction of 2 is q,

A region in which the sum (p + q) of the P and the q is an odd number among the plurality of regions arranged in a lattice pattern is defined as a first region group, and the sum (p + q) is an even number as a second region group, and at least two of the regions included in only one of the first region group and the second region group Connecting the regions in parallel, This is a transfer area or the output area.

By setting the group of regions connected in parallel as the excitation region, it is possible to excite the plate without destroying the resonance mode of the plate, and as a result, high efficiency can be expected. By setting the groups of regions connected in parallel as output regions, the vibration modes of the regions connected in parallel are aligned, so that the output voltage waveforms are aligned and the heat generated by the movement of charges between the output electrodes is generated. Avoidance, resulting in higher efficiency. In each of the above piezoelectric transformers, preferably,

A region in which the sum (p + q) of the P and the q is an odd number among the plurality of regions arranged in a lattice pattern is defined as a first region group, and the sum (p + q) is an even number as a second area group, and both the excitation area and the output area are only one of the first area group or the second area group. To be provided.

By doing so, the vibration modes are aligned in both the excitation area and the output area, and as a result, high efficiency can be expected. In each of the piezoelectric transformers, preferably, a ratio of a length of the region in the first direction to a length of the region in the second direction is 0.7 to 1.3. In each of the piezoelectric transformers, preferably, the first direction and the second direction are substantially orthogonal to each other.

In each of the above piezoelectric transformers, preferably, m and n are equal.

As described above, in the case where a plurality of regions divided into a grid with n sections in the first direction and m sections in the second direction are provided, one of the excitation area and the output area is set to the first area. When provided in all n sections in the direction, the other of the excitation area and the output area is preferably not provided in the entire n section in the first direction, and one of the excitation area electrode and the output area is When provided in all m sections in the second direction, it is preferable that the other of the excitation area and the output area is not provided in all m sections in the second direction.

The upper limits of m and n are not particularly limited, but are practically preferably 100 or less, more preferably 10 or less, respectively. BRIEF DESCRIPTION OF THE FIGURES

1A to 1E are views for explaining a piezoelectric transformer according to a first embodiment of the present invention. FIG. 1A is a top view, FIG. 1B is a bottom view, and FIG. 1C—FIG. 1E. Is a sectional view,

FIG. 2 is a perspective view illustrating a piezoelectric transformer according to a first embodiment of the present invention.

FIG. 3 is a circuit diagram for explaining the electrical connection of the piezoelectric transformer according to the first embodiment of the present invention at the time of boosting.

FIG. 4 is a circuit diagram for explaining electrical connection at the time of step-down of the piezoelectric transformer according to the first embodiment of the present invention.

FIG. 5A—FIG. 5G show the piezoelectric transformers of the first and sixth embodiments of the present invention. 5A, 5B, and 5C are plan views showing the expansion and contraction state of the veneer, and FIG. 5D shows the stress distribution in the state of FIG. 5A. 5E is a diagram showing a displacement distribution in the state of FIG. 5A, FIG. 5F is a diagram showing a stress distribution in the state of FIG. 5C, and FIG. 5G is a state of FIG. 5C. It is a diagram showing the displacement distribution in

FIGS. 6A to 6E are views for explaining a piezoelectric transformer according to a second embodiment of the present invention. FIG. 6A is a top view of an upper plate, FIG. 6B is a bottom view, and FIG. FIG. 6E is a cross-sectional view.

FIGS. 7A to 7E are views for explaining a piezoelectric transformer according to a second embodiment of the present invention. FIG. 7A is a top view of a lower plate, FIG. 7B is a bottom view, and FIG. FIG. 7E is a cross-sectional view,

FIG. 8 is a perspective view illustrating a piezoelectric transformer according to a second embodiment of the present invention.

FIG. 9 is a circuit diagram for explaining the electrical connection at the time of boosting of the piezoelectric transformer according to the second embodiment of the present invention.

FIG. 10 is a circuit diagram for explaining electrical connection at the time of step-down of the piezoelectric transformer according to the second embodiment of the present invention.

FIG. 11A—FIG. 11B is a diagram for explaining a piezoelectric transformer according to a third embodiment of the present invention. FIG. 11A is a top view, FIG. 11B is a bottom view, and FIG. 12 is a perspective view illustrating a piezoelectric transformer according to a third embodiment of the present invention,

FIG. 13 is a circuit diagram for explaining the electrical connection at the time of boosting of the piezoelectric transformer according to the third embodiment of the present invention.

FIG. 14 is a circuit diagram for explaining the electrical connection at the time of step-down of the piezoelectric transformer according to the third embodiment of the present invention.

FIGS. 15A and 15B illustrate a piezoelectric transformer according to a fourth embodiment of the present invention. 91

FIG. 15A is a top view, FIG. 15B is a bottom view, and FIG. 16 is a perspective view for explaining a piezoelectric transformer according to a fourth embodiment of the present invention. Yes,

FIG. 17 is a circuit diagram illustrating electrical connection of the piezoelectric transformer according to the fourth embodiment of the present invention.

FIGS. 18A and 18B are views for explaining a piezoelectric transformer according to a fifth embodiment of the present invention. FIG. 18A is a top view of the first layer, and FIG. 18B is a bottom view. And

FIGS. 19A and 19B are views for explaining a piezoelectric transformer according to a fifth embodiment of the present invention. FIG. 19A is a top view of the second layer, and FIG. 19B is a bottom view. And

FIGS. 20A and 20B are diagrams for explaining a piezoelectric transformer according to a fifth embodiment of the present invention. FIG. 20A is a top view of the third layer, and FIG. 20B is a bottom view. Yes,

FIGS. 21A and 21B are views for explaining a piezoelectric transformer according to a fifth embodiment of the present invention. FIG. 21A is a top view of a fourth layer, and FIG. 21B is a bottom view. And

FIG. 22 is a perspective view illustrating a piezoelectric transformer according to a fifth embodiment of the present invention.

FIG. 23 is a circuit diagram for explaining the electrical connection at the time of boosting of the piezoelectric transformer according to the fifth embodiment of the present invention.

FIG. 24 is a circuit diagram for explaining the electrical connection at the time of step-down of the piezoelectric transformer according to the fifth embodiment of the present invention.

FIG. 25A—FIG. 25E is a diagram for explaining a piezoelectric transformer according to a sixth embodiment of the present invention. FIG. 25A is a top view, FIG. 25B is a bottom view, and FIG. C to FIG. 25E are sectional views, 26A and 26B are partially enlarged views for explaining a piezoelectric transformer according to a sixth embodiment of the present invention. FIG. 26A is a partially enlarged top view, and FIG. 26B is a partially enlarged sectional view.

FIG. 27 is a perspective view illustrating a piezoelectric transformer according to a sixth embodiment of the present invention.

FIG. 28 is a circuit diagram for explaining the electrical connection at the time of boosting of the piezoelectric transformer according to the sixth embodiment of the present invention.

FIG. 29 is a circuit diagram for explaining the electrical connection at the time of step-down of the piezoelectric transformer according to the sixth embodiment of the present invention.

FIG. 3 OA—FIG. 3 OE is a diagram for explaining a piezoelectric transformer according to a seventh embodiment of the present invention. FIG. 3 OA is a top view of an upper plate, FIG. 30B is a bottom view, and FIG. FIG. 30E is a cross-sectional view,

FIG. 31A—FIG. 31E are views for explaining a piezoelectric transformer according to a seventh embodiment of the present invention. FIG. 31A is a top view of a lower plate, FIG. 31B is a bottom view, Figure 31C-Figure 31E is a cross-sectional view,

FIG. 32 is a perspective view illustrating a piezoelectric transformer according to a seventh embodiment of the present invention.

FIG. 33 is a circuit diagram for explaining the electrical connection at the time of boosting of the piezoelectric transformer according to the seventh embodiment of the present invention.

FIG. 34 is a circuit diagram for explaining electrical connection at the time of step-down of the piezoelectric transformer according to the seventh embodiment of the present invention.

35A and 35B are views for explaining a piezoelectric transformer according to an eighth embodiment of the present invention. FIG. 35A is a top view of the first layer, FIG. 35B is a bottom view,

36A and 36B are views for explaining a piezoelectric transformer according to an eighth embodiment of the present invention. FIG. 36A is a top view of the second layer, and FIG. 36B is a bottom view. Yes,

FIGS. 37A and 37B are diagrams for explaining a piezoelectric transformer according to an eighth embodiment of the present invention. FIG. 37A is a top view of the third layer, and FIG. 37B is a bottom view. And

FIGS. 38A and 38B are diagrams for explaining a piezoelectric transformer according to an eighth embodiment of the present invention. FIG. 38A is a top view of the fourth layer, and FIG. 38B is a bottom view. And

FIG. 39 is a partially enlarged top view for explaining a piezoelectric transformer according to an eighth embodiment of the present invention.

FIG. 40 is a perspective view illustrating a piezoelectric transformer according to an eighth embodiment of the present invention.

FIG. 41 is a circuit diagram for explaining an electrical connection at the time of boosting of the piezoelectric transformer according to the eighth embodiment of the present invention.

FIG. 42 is a circuit diagram for explaining electrical connection at the time of step-down of the piezoelectric transformer according to the eighth embodiment of the present invention.

FIGS. 43A to 43E are views for explaining the piezoelectric transformer according to the ninth embodiment of the present invention. FIG. 43A is a top view, FIG. 43B is a bottom view, and FIG. C Fig. 4 3 E is a sectional view,

FIG. 44 is a perspective view for explaining a piezoelectric transformer according to a ninth embodiment of the present invention.

FIG. 45 is a circuit diagram for explaining the electrical connection at the time of boosting of the piezoelectric transformer according to the ninth embodiment of the present invention.

FIG. 46 is a circuit diagram for explaining the electrical connection at the time of step-down of the piezoelectric transformer according to the ninth embodiment of the present invention.

Fig. 47 is a perspective view showing a conventional Rosen-type piezoelectric transformer. Fig. 48 shows a conventional (piezoelectric lateral effect-piezoelectric lateral effect) step-down piezoelectric transformer. FIG.

FIG. 49 is a perspective view showing a conventional (piezoelectric longitudinal effect-piezoelectric longitudinal effect) step-down piezoelectric transformer. Example

Next, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)

FIGS. 1A to 1E are views for explaining the piezoelectric transformer of this embodiment. FIG. 1A is a top view, FIG. 1B is a bottom view, and FIG. 1C to FIG. is there. FIG. 2 is a perspective view for explaining the piezoelectric transformer of the present embodiment. FIG. 3 is a circuit diagram for explaining the electrical connection at the time of boosting of the piezoelectric transformer of the present embodiment. FIG. 4 is a circuit diagram for explaining the electrical connection of the piezoelectric transformer of the present embodiment at the time of step-down. FIGS. 5A to 5G are diagrams for explaining the resonance operation of the piezoelectric transformer of the present embodiment, and FIGS. 5A, 5B, and 5C are plan views showing the contracted state of the single plate. 5D shows the stress distribution in the state of FIG. 5A, FIG. 5E shows the displacement distribution in the state of FIG. 5A, and FIG. 5F shows the stress distribution in the state of FIG. 5C. FIG. 5G is a diagram showing a distribution, and FIG. 5G is a diagram showing a displacement distribution in the state of FIG. 5C.

The flat plate 100 of the piezoelectric transformer 501 of this embodiment is a single plate (24 mm × 24 mm × l mm) of a PZT-based piezoelectric ceramics. Electrodes 1-18 are made of Pd-Ag conductive paste. As shown in FIGS. 1A and 1B, the electrode pattern is formed by screen printing square electrodes 118 in a 3 × 3 grid. This square electrode shape has corners to increase the dielectric breakdown strength between the electrodes, for example, corners 1 1 1 for electrode 1, 1 112, 1 1 3 for electrode 2 and 1 for electrode 103. It is desirable that all four corners of the center electrode 5 be rounded. The polarization treatment is performed in oil. polarization The direction is the direction (z direction) perpendicular to the two main surfaces (front and back) of the flat plate 100 as shown in FIGS. 1A, 1C, 1D, and 1E. In Fig. 1A, when "·" is shown in 〇, it indicates an upward polarization direction, and when "X" is shown in 〇, it is a downward polarization direction. This applies to the second and subsequent embodiments. After the polarization process, the piezoelectric transformer element is manufactured by performing the aging process. By doing so, the flat plate 100, which is square in plan view, is divided into three in the X direction and three in the y direction. Divided into 109.

FIG. 2 is a perspective view of the present piezoelectric transformer 501. The electrical connection is made between the square electrodes 1, 3, 5, 7, 9, 10, 10, 12, 14, 16, and 18 located at the nodes of the piezoelectric resonance vibration of the piezoelectric transformer 501. Remove from each center. For electrical connection, it is desirable to use a conductive elastic body such as 141-145. Further, an electrical connection with an external circuit is obtained by connecting a metal terminal 131-134 to the conductive elastic body 141-145.

This piezoelectric transformer can be used for both step-up and step-down applications by changing the electrical connection. Figure 3 shows the electrical connections when used for boosting. Figure 4 shows the electrical connections when used for step-down.

Further, the piezoelectric transformer of the present embodiment performs a resonance operation as shown in FIGS. 5A to 5G.

In the present embodiment, electrode pairs 5, 14 serving as excitation electrodes or output electrodes are arranged in the central region 105, and the peripheral regions 101, 103, 100 are arranged.

Since the output electrode or the excitation electrode is arranged in each of 7, 109, the cross-sectional area where the mechanical resonance energy propagates can be taken in four directions, and therefore the density of the mechanical resonance energy passing per unit area And the resulting power limit can be increased It has become.

In addition, since the peripheral regions 101, 103, 107, and 109 are connected in parallel to form an excitation region or an output region, the resonance mode of the flat plate 100 is maintained. Excitation is possible, and as a result, high efficiency can be expected.

(Second embodiment)

FIGS. 6A to 6E are views for explaining the piezoelectric transformer of this embodiment. FIG. 6A is a top view of the upper plate, FIG. 6B is a bottom view, and FIGS. 6C to 6E are It is sectional drawing. 7A to 7E are views for explaining the piezoelectric transformer of the present embodiment. FIG. 7A is a top view of the lower plate, FIG. 7B is a bottom view, and FIG. 7C—FIG. 7E is a cross-sectional view. It is. FIG. 8 is a perspective view for explaining the piezoelectric transformer of the present embodiment. FIG. 9 is a circuit diagram for explaining the electrical connection at the time of boosting of the piezoelectric transformer according to the present embodiment. FIG. 10 is a circuit diagram for explaining the electrical connection of the piezoelectric transformer of this embodiment at the time of step-down.

The flat plate of the piezoelectric transformer 502 of this embodiment is a laminated plate 5 10 (24 mm × 24 mm × 0.5 mm × 2 layers) in which two flat plates 100 and 200 of PZT piezoelectric ceramics are stacked. . The electrodes 113 are made of Pd-Ag conductive paste. As shown in FIG. 6A, FIG. 6B, FIG. 7A, and FIG. 7B, the electrode pattern is formed by screen printing square electrodes in a 3 × 3 grid. This square electrode shape has corners to increase the dielectric breakdown strength between the electrodes, for example, the corners 1 1 and 1 for electrode 1, the corners 1 2 and 1 13 for electrode 2, and the corners for electrode 103. 1 1 4; 4 corners for electrode 5; 2 1 1 for electrode 19; 2 2 and 2 13 for electrode 20; 2 1 4 for electrode 21; 2 1 4 for electrode 21; center electrode 2 In 3, it is desirable that all four corners are rounded. The polarization treatment is performed in oil. As shown in Fig. 6A, Fig. 6C-Fig. 6E, Fig. 7A, Fig. 7C-Fig. 7E, Fig. Direction (z-direction) perpendicular to the two main surfaces (front and back). After the polarization process, the piezoelectric transformer element is manufactured by performing an aging process. By doing so, the upper flat plate 100 of a square shape in plan view is divided into three in the X direction and three in the y direction. 0 1 — 1 0 9 is divided into two, and a flat plate with a square bottom in plan view 2 0 0 is divided into 3 in the X direction and 3 in the y direction. It is divided into the area 201-209.

FIG. 8 is a perspective view of the present piezoelectric transformer 502. FIG. The electrical connection is made on the upper and lower surfaces of the laminated plate 5 10 by square electrodes 1, 3, 5, 7, 9, 28, 3 located at the nodes of the piezoelectric resonance vibration of the piezoelectric transformer 502. Take out from the center of 0, 32, 34, 36, respectively. For electrical connection, it is desirable to use a conductive elastic body 141-145. Further, by connecting metal terminals 131, 132, 135, and 138 to the conductive elastic body 141-145, etc., electrical connection to an external circuit is established. The electrodes 10-18 provided on the back surface of the upper plate 100 and the electrodes 19-27 provided on the surface of the lower plate 200 are connected by epoxy-based bonding. Laminate with agents or join by integral sintering. By doing so, a laminated plate 5100 in which the upper plate 100 and the lower plate 200 are integrated is formed. Connection to electrodes 10, 12, 16, 18 provided on the back of upper plate 100, electrodes 19, 21, 25, 27 provided on the surface of lower plate 200 It is preferable that the metal terminal 137 formed of a soft wire that does not hinder vibration be soldered or the like.

In this embodiment, the electrode pairs 5, 3 serving as excitation electrodes or output electrodes are provided on the front surface of the central region 105 of the flat plate 100 and the back surface of the central region 205 of the flat plate 200. 2 and the output electrodes or excitation electrodes are placed in the peripheral areas 101, 103, 107 and 109 of the flat plate 100, respectively. Since the output electrode or the excitation electrode is arranged in each of the peripheral regions 201, 203, 207, and 209 of 200, the cross-sectional area where mechanical resonance energy propagates is square. Therefore, it is possible to reduce the density of the mechanical resonance energy passing per unit area, and as a result, it is possible to further increase the limit value of usable power.

In addition, the peripheral areas 101, 103, 107, 109 of the flat plate 100 are connected in parallel, and the peripheral areas 201, 203, 2 of the flat plate 200 are connected. Since 0 7 and 2 0 9 are connected in parallel as an excitation area or an output area, excitation is performed without disturbing the resonance mode of the laminated body 5 10 composed of the flat plates 1 0 0 and 2 0 0 As a result, high efficiency can be expected.

This piezoelectric transformer 502 can be used for step-up and step-down applications by changing the electrical connection. Figure 9 shows the electrical connections used for boosting. FIG. 10 shows the electrical connection when used for step-down.

(Third embodiment)

FIG. 11A and FIG. IB are views for explaining the piezoelectric transformer of the present embodiment. FIG. 11A is a top view, and FIG. 11B is a bottom view. FIG. 12 is a perspective view for explaining the piezoelectric transformer of the present embodiment. FIG. 13 is a circuit diagram for explaining the electrical connection of the piezoelectric transformer according to the present embodiment at the time of boosting. FIG. 14 is a circuit diagram for explaining the electrical connection of the piezoelectric transformer of the present embodiment at the time of step-down.

The flat plate 100 of the piezoelectric transformer 503 of this embodiment is made of a single plate (24 mm × 24 mm × 1 mm) of PZT-based piezoelectric ceramics. Electrodes 1-18 are made of Pd-Ag conductive paste. As shown in FIGS. 11A and 11B, an electrode pattern is formed by screen printing square electrodes in a 3 × 3 grid. This square electrode shape is the dielectric breakdown strength between the electrodes. For example, corner 1 1 1 for electrode 1, corner 1 1 2 and 1 13 for electrode 2, corner 1 1 4 for electrode 103, and 4 corners for center electrode 5. It is desirable that all be rounded. The polarization treatment is performed in oil. The polarization direction is a direction ( _Z direction) perpendicular to the two main surfaces (front and back) of the flat plate 100 as shown in FIGS. 11A and 12. After the polarization process, the piezoelectric transformer element is manufactured by performing an aging process. By doing so, the flat plate 100 having a square shape in plan view is divided into three in the X direction and three in the y direction. It is divided into 09.

FIG. 12 is a perspective view of the piezoelectric transformer 503 of this embodiment. The electrical connection is at the center of the square electrodes 1, 3, 5, 7, 9, 10, 0, 12, 14, 16, 18 located at the nodes of the piezoelectric resonance vibration of the piezoelectric transformer 503 Remove from the part. In addition, it is desirable to use a conductive elastic body 161 to 165 for electrical connection. The electrical connection between the electrodes can be achieved by applying a conductive paint to the element surface. Further, by connecting metal terminals 15 1-15 4 to the conductive elastic body 16 1-16 5 etc., electrical connection with an external circuit is established. In this piezoelectric transformer 503, the maximum step-up ratio is about {(square root of (3/2)) because three electrode plates are used on the input side and two electrode plates are used on the output side during step-up. It will be about twice.

In the present embodiment, the regions 105 and 109 are connected in parallel to form an excitation region or an output region, and the peripheral regions 101, 103, 107 and 109 are formed. Since they are connected in parallel to form an output area or an excitation area, vibration modes are aligned in both the excitation area and the output area, and excitation can be performed without breaking the resonance mode of the flat plate 100. It is possible, and as a result, high efficiency can be expected.

Fig. 13 shows the electrical connections for boost operation. Figure 14 shows the Shows the electrical connection for use.

(Fourth embodiment)

FIGS. 15A and 5B are views for explaining the piezoelectric transformer of the present embodiment. FIG. 15A is a top view and FIG. 15B is a bottom view. FIG. 16 is a perspective view for explaining the piezoelectric transformer of the present embodiment. FIG. 17 is a circuit diagram for explaining the electrical connection of the piezoelectric transformer according to the present embodiment.

The flat plate 100 of the piezoelectric transformer 504 of this embodiment is a single plate (24 mm × 24 mm × l mm) force of a PZT-based piezoelectric ceramic. The electrodes 118 are made of Pd-Ag conductive paste. As shown in FIGS. 15A and 15B, the electrode pattern is formed by screen printing square electrodes in a 3 × 3 grid. This square electrode shape has corners to increase the dielectric breakdown strength between the electrodes, for example, corners 11 1 1 for electrode 1, 112, 1 13 for electrode 2, and corners for electrode 103. It is desirable that all four corners of the center electrode 5 are rounded. The polarization treatment is performed in oil. The polarization direction is a direction (z direction) perpendicular to the two main surfaces (front and back) of the flat plate 100 as shown in FIGS. 15A and 16. After the polarization process, the piezoelectric transformer element is manufactured by performing an aging process. By doing so, the flat plate 100 having a square shape in plan view is divided into three in the X direction and three in the y direction. It is divided into 09. The piezoelectric transformer element is manufactured by performing aging treatment after the polarization treatment.

Fig. 16 shows a perspective view of the present piezoelectric transformer. The electrical connection is taken out from the center of the square electrode 118 located at the node of the piezoelectric resonance vibration of the present piezoelectric transformer. It is desirable to use a conductive elastic body 181-189 for electrical connection. The electrical connection between the electrodes can also be achieved by applying a conductive paint to the element surface. More conductive. Electrical connection to external circuits is established by connecting metal terminals 1 7 1-1 7 6 to 18 1 1-18 9 etc.

Excitation electrode terminals are provided at one location in A and D, and output electrode terminals are provided in two locations at B, E, C, and F. At this time, it is desirable that the resonance modes of the electrode plates connected to the electrodes B and C match.

Figure 17 shows the electrical connections for boost operation.

(Fifth embodiment)

Fig. 18A, Fig. 18B, Fig. 19A, Fig. 19B, Fig. 20A, Fig. 20B, Fig. 21A, Fig. 2 IB are diagrams for explaining the piezoelectric transformer of this embodiment. FIG. 18A is a top view of the first layer, FIG. 18B is a bottom view, FIG. 19A is a top view of the second layer, FIG. 19B is a bottom view, and FIG. A is a top view of the third layer, FIG. 20B is a bottom view, FIG. 21A is a top view of the fourth layer, and FIG. 21B is a bottom view. FIG. 22 is a perspective view for explaining the piezoelectric transformer of the present embodiment. FIG. 23 is a circuit diagram for explaining the electrical connection at the time of boosting of the piezoelectric transformer of the present embodiment. FIG. 24 is a circuit diagram for explaining the electrical connection of the piezoelectric transformer of the present embodiment at the time of step-down.

The flat plate of the piezoelectric transformer 505 of the present embodiment is a laminated plate of four layers 310, 320, 330, 340 of PZT-based piezoelectric ceramics 52 0 (24 mm X 24 mm X 0.5 X 4 mm). The electrodes 401-456 are made of a Pd-Ag-based conductive paste. Electrode patterns are formed by screen printing square electrodes in a 3 × 3 grid as shown in FIGS. However, the electrodes on the surface exposed to the outside (the surface of the first layer 310 and the back surface of the fourth layer 340) are arranged only in the central area, and the conductive paste is not printed on the other areas. . With such a structure, a long distance between the input and output electrodes can be ensured. Therefore, the dielectric strength between input and output will increase.

The shape of these square electrodes 4 0 1-4 5 6 depends on the breakdown strength between the electrodes. It is desirable that the corners be rounded to increase the degree. The polarization treatment is performed in oil. As shown in Fig. 18-22, the polarization direction is the direction (z direction) perpendicular to the two main surfaces (front and back) of each of the flat plates 310, 320, 3330, and 340. ). After the polarization process, the aging process is performed to produce a piezoelectric transformer element. In this way, the first layer flat plate 310 having a square shape in plan view is divided into three in the X direction and three in the y direction. 1 2-3 1 9 is divided into two, and the flat plate of the second layer, which is square in plan view, is divided into 3 in the X direction and 3 in the y direction. The area is divided into three areas 3 2 1-3 2 9, and the flat plate of the third layer, which is square in plan view, is divided into 3 sections in the X direction and 3 sections in the y direction. Divided into 9 grid-like areas 3 3 1-3 3 9, the flat plate of the fourth layer 3 4 0, which is square in plan view, is divided into 3 in the X direction and 3 in the y direction, totaling 3 X It is divided into three 9-segment grids, 3 4 1 — 3 4 9.

FIG. 22 is a perspective view of the present piezoelectric transformer 505. Electrical connection is taken from the center of the square electrodes 401, 456 located at the nodes of the piezoelectric resonance vibration of the piezoelectric transformer 505 on the upper and lower surfaces of the laminated plate 520 . It is desirable to use a conductive elastic body 361 for electrical connection. Further, by connecting metal terminals 35 1 and 35 2 to the conductive elastic body 36 1 and the like, electrical connection with an external circuit is obtained.

In addition, the connection between the electrode 4 0 2 4 0 provided on the back surface of the first layer flat plate 3 10 and the electrode 4 11 1-4 19 provided on the surface of the second layer flat plate 3 2 0, Connection of the electrodes 420-428 provided on the back surface of the flat plate 320 of the second layer with the electrodes 42-9-438 provided on the surface of the flat plate 330 of the third layer; The connection between the electrode 4 3 8-4 4 6 provided on the back of the three-layer plate 3 3 0 and the electrode 4 4 7-4 5 5 provided on the surface of the fourth layer 3 4 0 Electrode Bond each other with an epoxy-based adhesive, or join them by integral sintering. In this manner, a laminated plate 520 in which the first to fourth flat plates 310, 320, 330, and 340 are integrated is formed. Connection to electrodes 402, 404, 408, 410 provided on the back surface of the first layer flat plate 310, electrodes 411, 413, provided on the surface of the second layer flat plate 320. Connection to 417, 419, connection to electrodes 438, 440, 444, 446 provided on the back surface of the third layer plate 330, provided to the surface of the fourth layer plate 340 The connection to the electrodes 447, 449, 453, 455 is desirably performed by soldering the tip of the metal terminal 353 formed of a soft wire that does not hinder vibration. In FIG. 22, the metal terminal 353 is drawn so as to be connected only to the region on the right side in the figure, but is similarly connected to the region on the left side in the figure.

In addition, connection to the electrodes 420, 422, 426, and 428 provided on the back surface of the second layer flat plate 320, and connection to the electrodes 429, 431, 435, and 433 provided on the surface of the third layer flat plate 330 It is desirable to make the connection by soldering the tip of the metal terminal 354 formed of a soft wire that does not hinder the vibration.

In this embodiment, an electrode serving as an excitation electrode or an output electrode is provided on the surface of the central region 3 15 of the first layer flat plate 3 10 and the bottom surface of the central region 345 of the fourth layer flat plate 340. Pairs 40 1 and 456 are arranged respectively, and output electrodes or excitation electrodes are arranged in the areas 3 11, 3 13, 3 17 and 3 19 around the first flat plate 3 10 respectively. An output electrode or an excitation electrode is arranged in each of the regions 32 1, 323, 327, and 329 around the second layer flat plate 320, and the regions 33 1, 3 around the third layer flat plate 330 are arranged. Output electrodes or excitation electrodes are placed on 33, 33 7 and 339, respectively, and are placed in the areas 34 1, 343, 34 7 and 349 around the fourth layer flat plate 340. Since the output electrode or the excitation electrode is disposed, the cross-sectional area where the mechanical resonance energy propagates can be taken in four directions, thereby reducing the density of the mechanical resonance energy that passes through per unit area. As a result, it is possible to raise the limit of power that can be used as a result. Also, the regions 3 11, 3 13, 3 17, 3 19 around the first layer flat plate 3 10 are connected in parallel, and the area 3 around the second layer flat plate 3 20 is connected. 2 1, 3

2 3, 3 2 7, 3 2 9 are connected in parallel, the area 3 3 1, 3 3 3, 3 3 7, 3 3 9 around the third layer flat plate 3 3 0 are connected in parallel, The area 3 4 1, 3 4 3, 3 4 7, 3 4 9 in the peripheral part of the flat plate 3 4 0 of the fourth layer is connected in parallel to form an output area or an excitation area. 3 2 0, 3

Excitation can be performed without destroying the resonance mode of the laminate 520 composed of 30 and 340, and as a result, high efficiency can be expected.

In the present embodiment, the excitation electrode portion and the output electrode portion are not arranged on the same layer or in the same plane, so that the insulation between the excitation electrode and the output electrode can be improved, and the piezoelectric transformer The dielectric strength between input and output can be greatly improved. For example, when the piezoelectric transformer of this embodiment is applied to an AC adapter or the like, it becomes possible to increase the electrical independence between the commercial AC power supply and the device.

This piezoelectric transformer can be used for both step-up and step-down applications by changing the electrical connection. Figure 23 shows the electrical connections used for boosting. Figure 24 shows the electrical connections when used for step-down.

As described above, in the first to fifth embodiments, the output can be increased, the efficiency can be reduced, the cost can be reduced, the thickness can be reduced, and the degree of freedom in selecting the transformer ratio is high. A piezoelectric transformer that can be used as a multi-output transformer is provided.

(Sixth embodiment) FIGS. 25A to 25E are views for explaining the piezoelectric transformer of this embodiment. FIG. 25A is a top view, FIG. 25B is a bottom view, and FIG. 25C to FIG. 25E are cross-sectional views. . 26A and 26B are partially enlarged views for explaining the piezoelectric transformer of the present embodiment, and FIGS. 26A and 26B are a partially enlarged top view and a partially enlarged sectional view of a region 105, respectively. FIG. 27 is a perspective view for explaining the piezoelectric transformer of this example. FIG. 28 is a circuit diagram for explaining electrical connection at the time of boosting of the piezoelectric transformer according to the present embodiment. FIG. 29 is a circuit diagram for explaining the electrical connection of the piezoelectric transformer of this example at the time of step-down. FIGS. 5A to 5G are diagrams for explaining the resonance operation of the piezoelectric transformer of the present embodiment, and FIGS. 5A, 5B, and 5C are plan views showing the expanded and contracted states of the single plate. 5D is a diagram illustrating the stress distribution in the state of FIG. 5A, FIG. 5E is a diagram illustrating the displacement distribution in the state of FIG. 5A, and FIG. 5F is a diagram illustrating the stress distribution in the state of FIG. 5C. FIG. 5G is a diagram showing a displacement distribution in the state of FIG. 5C.

The flat plate 100 of the piezoelectric transformer 501 of this embodiment is a single plate (24 mm X 24 mm X 1 mm) of a PZT-based piezoelectric ceramic. The electrodes 118, 5 ', and 14' are made of a Pd-Ag-based conductive paste. As shown in Fig. 1, the electrode pattern is formed by screen printing electrodes 1-1, 5, 5, 14 'in a 3x3 grid.

Electrodes 1, 4, 6-13, 15-18 have a square shape, and this square electrode shape has corners to increase the dielectric breakdown strength between the electrodes. It is desirable that the corners 112, 113 for the electrode 1, and the electrode 112, and the corners 114 for the electrode 103, be rounded. The outer shapes of the electrodes 5 ′ and 14 ′ are also square, and it is desirable that all the four corners of the square electrode are rounded in order to increase the dielectric strength.

The inside of the electrodes 5 ′ and 14 ′ is hollowed out in a circular shape and has a circular opening. Parts 120 and 121 are formed respectively. The top and bottom surfaces of the flat plate 100 are exposed from the openings 120 and 121 respectively. Circular electrodes 5 and 14 are provided concentrically with the circular openings 120 and 121, respectively. The center of the square of the outer shape of the electrode 5 'and the center of the circular opening 1 20 coincide with the center of the circular electrode 5, and the center of the square of the outer shape of the electrode 14' matches the center of the circular electrode. The center of the opening 1 21 coincides with the center of the circular electrode 14.

The polarization treatment is performed in oil. The direction of polarization is as shown in Fig. 25A, Fig. 25C-Fig. 25E for the surrounding areas 101-104 and 106-109. It is the direction (z direction) perpendicular to (front and back). As shown in FIGS. 26A and 26B, the polarization of the region 105 is radial with respect to the center of the circular electrode 5 and almost parallel to the main surface (front surface, back surface) of the flat plate 100. A voltage is applied between the electrode terminals B and D so that the polarization direction is oriented in the desired direction. Further, it is preferable that the flat plate 100 between the electrode 5 and the electrode 14 be polarized in a direction perpendicular to the two main surfaces (the front surface and the back surface). After the polarization process, the piezoelectric transformer element is manufactured by performing an aging process. By doing so, the flat plate 100 having a square shape in plan view is divided into three in the X direction and three in the y direction. 0 is divided into nine.

FIG. 27 is a perspective view of the piezoelectric transformer 501 of this embodiment. The electrical connection is made in the areas 101, 103, 107, 109 at the nodes of the piezoelectric resonance vibration of the piezoelectric transformer 501, and the square electrodes 1, 3, 7, 9 , 10, 12, 16, and 18 are taken out from the center of each. In the region 105, the electrode terminal portion B is taken out from the center of the center circular electrode 5 located at the node of the piezoelectric resonance vibration of the piezoelectric transformer 501, while the electrode terminal portion D is taken out of the outer side. Take out near the corner of electrode 5 '. Electrical It is desirable to use a conductive elastic body 141-146 or the like for the connection. In addition, electrical connection to external circuits is established by connecting metal terminals 13 1 1 to 13 4 to the conductive elastic body 1 4 1 1 1 4 6 and the like.

This piezoelectric transformer can be used for both step-up and step-down applications by changing the electrical connection. Figure 28 shows the electrical connections when used for boosting. Figure 29 shows the electrical connections when used for step-down.

Further, the piezoelectric transformer of this embodiment performs a resonance operation as shown in FIG. In this embodiment, an electrode pair 5, 5 'serving as an excitation electrode or an output electrode is arranged in a central region 105, and a peripheral region 101, 103, 107, 1 is formed. Since an output electrode or an excitation electrode is placed on each of the components 9, the cross-sectional area where mechanical resonance energy propagates can be taken in four directions, so that the density of mechanical resonance energy that passes through per unit area can be reduced. It is possible to raise the limit of the power that can be used as a result.

Further, in the present invention, one of the excitation region and the output region is a region in which the polarization is in a direction substantially parallel to the two main surfaces (the front surface and the rear surface) of the flat plate 100, and the excitation region and the output region are arranged. Since the other of the regions is a region in which the polarization is almost perpendicular to the two main surfaces (front surface and back surface) of the flat plate 100, the ratio between the input impedance and the output impedance can be made large, and as a result, the voltage A larger ratio or step-down ratio can be taken.

Also, in the region 105, a circular opening 120 is provided inside the outer electrode 5, and concentric with the circular opening 120 inside the opening 120. Since the circular electrode 5 is provided, when a voltage is applied between these electrodes 5 and 5 ′ to perform polarization, the electric field intensity applied to the element during polarization becomes uniform, and the circular electrode 5 is formed. Can be uniformly polarized radially with respect to the center. (Seventh embodiment)

Fig. 3 OA-30E is a diagram for explaining the piezoelectric transformer of this embodiment. Fig. 3 OA is a top view of the upper plate, Fig. 30B is a bottom view, and Fig. 30C-Fig. 30E is a cross-sectional view. It is. FIGS. 31A-31E are views for explaining the piezoelectric transformer of this embodiment. FIG. 31A is a top view of the lower plate, FIG. 31B is a bottom view, and FIG. FIG. 31E is a cross-sectional view. FIG. 32 is a perspective view for explaining the piezoelectric transformer of this example. FIG. 33 is a circuit diagram for explaining the electrical connection at the time of boosting of the piezoelectric transformer according to the present embodiment. FIG. 34 is a circuit diagram for explaining the electrical connection at the time of step-down of the piezoelectric transformer according to the present embodiment.

The flat plate of the piezoelectric transformer 502 of this embodiment is a laminated plate 5 10 (24 mm × 24 mm × 0.5 mm × 2 layers) in which two flat plates 100 and 200 of PZT piezoelectric ceramics are stacked. The electrodes 1-36, 5 ', 14, 24, 23', and 32 'are made of Pd-Ag conductive paste. As shown in Fig. 30A, Fig. 30B, Fig. 31A and Fig. 31B, the electrodes 1-36, 5,, 14, 24, 23,, 32, are arranged in a 3x3 grid. Formed by screen printing.

Electrodes 114, 6—13, 15—22, 24—31, and 33—36 have a square shape, and this square electrode shape has corners to increase the dielectric breakdown strength between the electrodes. For example, electrode 1 has a corner 1 1 1, electrode 2 has a corner 1 1 2, 1 1 3, electrode 103 has a corner 1 1 4, electrode 1 9 has a corner 2 1 1, and electrode 20 has a corner 2. It is desirable that the corners 2 14 of the electrodes 2, 2 1 3 and the electrode 21 be rounded. The outer shape of the electrodes 5, 14, 25, 23 'and 32' is also square, This square electrode shape is preferably rounded at all four corners in order to increase the dielectric breakdown strength.

The inside of the electrodes 5 ′, 14 ′, 23 ′, 32 ′ is hollowed out in a circular shape, and circular openings 120, 122, 220, 221 are formed respectively. The top and bottom surfaces of the flat plate 100 are exposed from the openings 120 and 121, respectively, and the top and bottom surfaces of the flat plate 200 are exposed from the openings 220 and 221 respectively. Circular electrodes 5, 14, 23, and 32 are provided concentrically with the circular openings 120, 122, 220, and 221, respectively. The center of the square of the outer shape of the electrode 5 ′ and the center of the circular opening 120 coincide with the center of the circular electrode 5, and the center of the square of the outer shape of the electrode 14 ′ matches the center of the circular electrode. The center of the opening 1 2 1 coincides with the center of the circular electrode 14, and the center of the square electrode, the center of the circular opening 220, and the center of the circular electrode 23, which are the outer shape of the electrode 23 ′, The center of the square shape, which is the outer shape of the electrode 32 ', the center of the circular opening 221 and the center of the circular electrode 32 match.

The polarization treatment is performed in oil. The direction of polarization depends on the surrounding areas 101-104, 106-109, 201-204, and 206-209, as shown in Fig. 30A and Fig. 32. It is the direction (z direction) perpendicular to each of the two main surfaces (front and back). As shown in FIGS. 30A and 30D, the polarization of the region 105 is radiating from the center of the circular electrode 5 in a direction substantially parallel to the main surface (front surface, back surface) of the flat plate 100. A voltage is applied between the electrode terminals B and D so that the polarization direction is oriented. Further, it is preferable that the flat plate 100 between the electrode 5 and the electrode 14 ′ is polarized in a direction perpendicular to the two main surfaces (the front surface and the back surface). As shown in FIG. 31A and FIG. 3ID, the polarization of the region 205 is radial to the center of the circular electrode 23 and substantially parallel to the main surface (front surface, back surface) of the flat plate 200. Direction 4 _n ^, _m

PCT / JP98 / 05891

38, a voltage is applied between the electrode 23 and the electrode 23 '. Further, it is preferable that the flat plate 200 between the electrode 23 and the electrode 32 'be polarized in a direction perpendicular to the two main surfaces (the front surface and the back surface). After the polarization process, the piezoelectric transformer element is manufactured by performing an aging process.

By doing so, the flat plate 100 having a square upper plate in a plan view 100 is divided into three regions in the X direction and three regions in the y direction. — Nine areas in a grid with a total of 3 X 3 divisions 201- Divided into 209.

FIG. 32 is a perspective view of the present piezoelectric transformer 502. The electrical connection is made by the square electrodes 1, 3, which are located at the nodes of the piezoelectric resonance vibration of the piezoelectric transformer 502 on the surfaces of the regions 101, 103, 107, and 109 on the upper surface of the laminate 5110. The square electrodes 28, which are located at the nodes of the piezoelectric resonance vibration of the piezoelectric transformer 502 on the surfaces of the regions 201, 203, 207, and 209 on the lower surface of the laminate 5 10 Take out from the center of 30, 34 and 36 respectively. In the region 105, the electrode terminal portion B is taken out from the center of the central circular electrode 5 located at the node of the piezoelectric resonance vibration of the piezoelectric transformer 502, while the electrode terminal portion D is taken out of the outer electrode 5, From the vicinity of the corner. It is desirable to use a conductive elastic body 141-146 or the like for electrical connection. Further, by connecting metal terminals 131, 132, and 134-137 to the conductive elastic members 141-146 and the like, electrical connection with an external circuit is established.

Incidentally, the upper plate 1 00 electrode 1 0 1 provided on the back surface of ^8, 1 4, connection of the electrodes provided 1 9 2 7, 23 'on the surface of the lower plate 200 and respectively corresponding electrodes to each other Are bonded by epoxy adhesive or joined by integral sintering. And by doing so, the upper plate 100 and the lower plate 99/34454

PCT / JP98 / 05891

39 A laminated plate 5 10 integrated with the plate 200 is formed. Connection to electrodes 10, 12, 16, 18 provided on the back of upper plate 100 and electrodes 19, 21, 25, 27 provided on the surface of lower plate 200 inhibits vibration It is desirable to solder the metal terminal 137 formed of a soft wire so as not to cause such a problem.

In the present embodiment, electrode pairs 5 and 5 ′ serving as excitation electrodes or output electrodes are arranged on the surface of the central region 105 of the flat plate 100, and the peripheral region 101, Output electrodes or excitation electrodes are placed on 103, 107, and 109, respectively, and output electrodes or excitation electrodes are placed on the peripheral areas 201, 203, 207, and 209 of the flat plate 200, respectively. , The cross-sectional area where mechanical resonance energy propagates can be taken in all directions, and therefore, the density of mechanical resonance energy passing per unit area can be reduced, and as a result, It is possible to raise the limit.

Also, the areas 101, 103, 107, and 109 at the periphery of the plate 100 are connected in parallel, and the areas 201, 203, 207, and 209 at the periphery of the plate 200 are connected in parallel. As the excitation region or the output region, it is possible to excite the laminate 5100 composed of the flat plates 100 and 200 without breaking the resonance mode, and as a result, high efficiency can be expected. It has been

Further, in this embodiment, the regions 105 and 205, which are one of the excitation region and the output region, are divided into two main surfaces (a front surface and a back surface) of a flat plate 100 and two main surfaces (a back surface) of a flat plate 200. (The front and back sides) and the areas 101 1, 103, 107, 109, 201, 203, 207, and 209 which are the other areas of the excitation area and the output area. The polarization is the two principal surfaces of the plate 100 (front, back) and the two principal surfaces of the plate 200 (front. Since the region is almost perpendicular to the back surface, the ratio between the input impedance and the output impedance can be increased. As a result, the step-up ratio or the step-down ratio can be increased.

In the region 105, a circular opening 120 is provided inside the outer electrode 5, and a circular electrode 5 concentric with the circular opening 120 is provided in the opening 120. When a voltage is applied between these electrodes 5 and 5 ′ to perform polarization, the electric field intensity applied to the element during polarization becomes uniform and the center of the circular electrode 5 is displaced. Radially uniform polarization processing. In the region 205, a circular opening 220 is provided inside the outer electrode 23, and a circular electrode concentric with the circular opening 220 is provided in the opening 220. Since a voltage is applied between these electrodes 23 and 23 to perform polarization, the electric field intensity applied to the element during polarization is uniform, and a circular electrode 23 is provided. Can be uniformly polarized radially with respect to the center.

This piezoelectric transformer 502 can be used for step-up and step-down applications by changing the electrical connection. Figure 33 shows the electrical connections used for boosting. Figure 34 shows the electrical connections when used for step-down.

(Eighth embodiment)

Fig. 35A, Fig. 35B, Fig. 36A, Fig. 36B, Fig. 37A, Fig. 37B, Fig. 38A, Fig. 38B illustrate the piezoelectric transformer of this embodiment. 35A is a top view of the first layer, FIG. 35B is a bottom view, FIG. 36A is a top view of the second layer, and FIG. 36B is a bottom view. 37A is a top view of the third layer, FIG. 37B is a bottom view, FIG. 38A is a top view of the fourth layer, and FIG. 38B is a bottom view. FIG. 39 is a partially enlarged top view for explaining regions 3 15, 3 25, 3 35, and 3 45 of the piezoelectric transformer of this embodiment. FIG. 40 is a perspective view for explaining the piezoelectric transformer of this embodiment. 4 1, _c is a circuit diagram for explaining an electrical connection when the piezoelectric transformer boosting the present embodiment FIG. 42 is a circuit diagram for explaining the electrical connection of the piezoelectric transformer of this example at the time of step-down.

The flat plate of the piezoelectric transformer 505 of this embodiment is a laminated plate 5 20 (24 mm X 24 mm X 0.5 X) of four layers of PZT-based piezoelectric ceramics 31 0, 320, 330, and 340. 4 mm). Electrodes 4 0 1 — 4 56, 40 1,, 40 6 ′, 4 15 ′, 4 24 ′, 4 3 3 ′, 442 ′, 4 5 1 ′, 4 5 6 ′ are P d — Ag It consists of a conductive paste of the system. The electrode pattern is shown in Fig. 35A-Electrode 40 1-4 56, 40 1 ', 40 6', 4 15 ', 4 24', 4 4 3 3 ′, 442 ′, 45 1 ′, and 45 6 ′ are formed by screen printing. However, the electrodes on the surfaces exposed to the outside (the surface of the first layer 310 and the back surface of the fourth layer 340) are arranged only in the central area, and the conductive paste is not printed on the other areas. With such a structure, a long distance between the input and output electrodes can be ensured. Therefore, the dielectric strength between input and output will increase. In addition, the effect of preventing migration due to the humidity in the outside air is increased.

Electrodes 40 2—4 0 5,40 7—4 1 4,4 1 6—4 2 3,4 2 5—4 3 2,4 34—44 1,44 3—4 5 0,4 5 2 -4 5 5 has a square shape, and it is desirable that the square electrode shape has rounded corners in order to increase the dielectric breakdown strength between the electrodes. The outer shapes of the electrodes 401, 406, 415 ', 424, 433, 442', 451, 456 are also square, and this square electrode shape Preferably, all four corners are rounded to increase the dielectric strength.

The inside of the electrodes 40 1 ′, 406 ′, 4 15 ′, 4 24 ′, 4 3 3 ′, 442 ′, 4 5 1 ′, 4 5 6 ′ is hollowed out in a circular shape and has a circular opening. Parts 46 1, 4 65, 4 62, 4 66, 4 63, 4 67, 4 64 and 4 68 are formed respectively. From this opening 4 6 1, 4 6 5 flat plate 3 1 0 The top and bottom surfaces of the flat plate 320 are exposed from the openings 462 and 466, respectively, and the top and bottom surfaces of the flat plate 330 are exposed from the openings 463 and 467.The flat plates are exposed from the openings 464 and 468. The surface and bottom of 340 are exposed. The circular openings 46 1, 465, 462, 466, 463, 467, 464, 468 and the concentric circular electrodes 401, 406, 415, 424, 433, 442, 451, respectively. , 456 are provided respectively.

The center of the square shape, which is the outer shape of the electrode 40 1 ′, and the center of the circular opening 46 1 coincide with the center of the circular electrode 401, and the outer shape of the electrode 406, The center of the opening 465 coincides with the center of the circular electrode 406, and the center of the square opening and the center of the circular opening 462, which is the outer shape of the electrode 415, and the center of the circular electrode 415 The center coincides with the center of the square shape which is the outer shape of the electrode 424, the center of the circular opening 466 matches the center of the circular electrode 424, and the square center which is the outer shape of the electrode 433 '. The center of the circular opening 46 3 coincides with the center of the circular electrode 43 3, and the center of the square center and the circular opening 46 7, which is the outer shape of the electrode 442, and the circular electrode 442. Center of the electrode 45 1 ′, the center of the square shape and the center of the circular opening 464 coincide with the center of the circular electrode 45 1, It is coincident with the contour at which the centers of the circular electrode 45 6 square central portion and a circular opening 468 of the pole 456 '.

The polarization treatment is performed in oil. The direction of polarization depends on the surrounding area 3 1 1—3 1 4, 3 16—3 19, 32 1—324, 326—329, 3 31—3 34, 336—3 39, 34 1— For 344, 346—349, as shown in Fig. 35A and Fig. 38B, each of the two main surfaces (front surface and back surface) of the flat plates 310, 320, 330, and 340 are perpendicular to each other. As shown in FIG. 35A, the polarization of the _c region 3 15 in the direction (z direction) is A voltage is applied between the electrode terminals B and D so that the direction of polarization is radial to the center of 6 and almost parallel to the main surface (front surface, back surface) of the flat plate 310. Do. Further, it is preferable that the flat plate 310 between the electrode 410 and the electrode 406 be polarized in a direction perpendicular to the two main surfaces (the front surface and the back surface). As shown in FIGS. 36A and 39, the polarization of the region 325 is radial with respect to the center of the circular electrodes 415 and 424, and the main surface of the flat plate 320 (surface The voltage is applied between the electrode terminals B and D so that the polarization direction is almost parallel to the back surface. Further, it is preferable that the flat plate 320 between the electrodes 415 and 424 ′ is polarized in a direction perpendicular to the two main surfaces (front and back). As shown in FIGS. 37A and 39, the polarization of the region 335 is radial with respect to the center of the circular electrodes 433 and 442, and the principal surface of the flat plate 330 is shown in FIG. The voltage is applied between the electrode terminals B and D so that the polarization direction is almost parallel to the front and back surfaces. Further, it is preferable that the flat plate 330 between the electrode 43 3 ′ and the electrode 44 2 ′ is polarized in a direction perpendicular to the two main surfaces (front and back surfaces). As shown in FIGS. 38A and 39, the polarization of the region 345 is radial with respect to the center of the circular electrodes 451, 456 and the principal surface of the flat plate 340 (surface, The voltage is applied between the electrode terminals B and D so that the polarization direction is almost parallel to the back surface. Further, it is preferable that the flat plate 340 between the electrode 451 'and the electrode 456' be polarized in a direction perpendicular to the two main surfaces (the front surface and the back surface). The piezoelectric transformer element is manufactured by performing aging treatment after polarization treatment.

By doing this, the flat plate 3 1 0 of the first layer, which is square in plan view, is divided into three in the X direction and three in the y direction, for a total of three 9-square grids 3 1 1-3 1 9 is divided into two, and the flat plate of the second layer, which is a square shape in plan view, is divided into 3 in the X direction and 3 in the y direction. Divided into three areas 3 2 1-3 2 9, square in plan view The 3rd layer of the 3rd layer is divided into 9 areas 3 3 1-3 3 9 in a grid of 3 X 3 divided into a total of 3 divided in the X direction and 3 divided in the y direction. The flat plate 340 of the fourth layer, which is square in shape, is divided into nine grid-like regions 34 1 to 349 of a total of 3 × 3 divided into three in the X direction and three in the y direction.

Figure 35A—As shown in Figure 40, electrodes 401, 406, 415, 424, 433, 442, 451, and 456 are flat plates 310, 32 0, 3 3 0,

They are connected to each other by through holes 471 provided in 340, and electrodes 401 ', 406', 415 ', 424', 433 ', 442', 451, ...

456, are connected to each other by through holes 472 provided in the flat plates 310, 320, 330, 340. By conducting the electrodes of each flat plate through the through holes in this way, it is possible to efficiently input and output electric energy not only from the layer directly connected to the outside but also from the intermediate layer. FIG. 40 shows a perspective view of the present piezoelectric transformer 50'5. For the electrical connection, on the upper surface of the laminated plate 520, for the electrode terminal portion B, the center of the circular electrode 401 of the region 3 15 located at the node of the piezoelectric resonance vibration of the piezoelectric transformer 505 is connected. The electrode is taken out from the center, but the electrode terminal D is taken out from the vicinity of the corner of the electrode 401, outside the region 315. On the lower surface of the laminated plate 520, take out from the center of the circular electrode 471 in the center of the region 345 located at the node of the piezoelectric resonance vibration of the piezoelectric transformer 505 to the electrode terminal B. I do. It is desirable to use a conductive elastic body 361, 362 or the like for electrical connection. Further, by connecting metal terminals 351, 352, 356 to the conductive elastic bodies 361, 362 and the like, electrical connection with an external circuit is established.

Note that the electrodes 402-410, 406 'provided on the back surface of the flat plate 310 of the first layer and the electrodes 41-11-419 provided on the surface of the flat plate 320 of the second layer 4 1 5 'connection, electrodes 4 2 0-4 28, 4 24 ′ provided on the back surface of the second layer flat plate 3 2 0 and electrodes 4 2 provided on the surface of the third layer flat plate 3 30 9 -Electrodes 438-446, 442 'provided on the back of the third flat plate 330, and the electrodes 447-455, provided on the surface of the fourth flat plate 340. For the connection of 45 1 ′, the corresponding electrodes are bonded to each other with an epoxy-based adhesive or joined by integral sintering. By doing so, the first layer-the fourth layer flat plate 310,

A laminate 520 in which 320, 330, and 340 are integrated is formed.

Connection to the electrodes 402, 404, 408, 410 provided on the back surface of the first layer flat plate 310, and the electrodes 4 11 1, 413, 4 provided on the surface of the second layer flat plate 320 Connections to 17 and 4 19, Electrodes 438, 440, 444 and 446 provided on the back of the third layer plate 330, Electrodes provided on the surface of the fourth layer plate 330 It is desirable that the connection to 444, 449, 453, and 455 be performed by soldering the tip of the metal terminal 353 formed of a soft wire that does not hinder vibration. In FIG. 40, the metal terminal 353 is drawn so as to be connected only to the region on the right side in the figure, but is similarly connected to the region on the left side in the figure.

In addition, electrodes 420, 422, and

Connections to 426 and 428, and connections to electrodes 429, 431, 435, and 377 provided on the surface of the third layer flat plate 330 are made of metal terminals 354 formed of soft wires that do not hinder vibration. It is desirable to do this by soldering the tip.

In this embodiment, an electrode pair 401, 401 serving as an excitation electrode or an output electrode and electrode pairs 406, 406 'are provided on the front and back surfaces of the central region 315 of the first layer flat plate 310. The electrode pairs 4 15 and 4 15 and the electrode pairs 424 and 424 ′ serving as excitation electrodes or output electrodes are placed on the front and back surfaces of the central region 325 of the flat plate 320 of the second layer, respectively. And placed on the front and back surfaces of the central area 335 of the third layer flat plate 330, respectively. Electrode pairs 443 3, 433 'and electrode pairs 442, 442', which serve as excitation electrodes or output electrodes, are respectively arranged, and excitation electrodes or electrodes are provided on the front and back surfaces of the central region 345 of the fourth layer flat plate 340. The electrode pairs 45 1, 45 1 and the electrode pairs 456, 456, which serve as output electrodes, are respectively arranged, and the areas 3 1 1, 3 1 3, 3 1 7, 3 1 An output electrode or an excitation electrode is arranged at 3 19 respectively, and an output electrode or an excitation electrode is arranged at the area 32 1, 323, 327, 329 of the peripheral portion of the flat plate 320 of the second layer. , The area of the periphery of the third layer flat plate 3 30 3 3 1,

Output electrodes or excitation electrodes are arranged at 33, 33, 337, and 339, respectively, and output electrodes or excitation electrodes are arranged at the area 341, 343, 347, 349 around the fourth layer flat plate 340, respectively. Since the electrodes are arranged, the cross-sectional area where the mechanical resonance energy propagates can be taken in four directions, so that the density of the mechanical resonance energy that passes per unit area can be reduced, and as a result, the power that can be used It is possible to raise the limit value of

In addition, the regions 3 11, 3 13, 3 17, and 3 19 in the peripheral portion of the first layer flat plate 3 10 are connected in parallel, and the regions 32 1 and 32 in the peripheral portion of the second layer flat plate 320 are connected. Three

23, 327, 329 are connected in parallel, the area 331, 333, 337, 339 around the third layer plate 330 is connected in parallel, and the fourth layer plate 3 is connected.

Since the areas 34 1, 343, 347, and 349 at the periphery of 40 are connected in parallel to form the output area or the excitation area, the flat plates 3 10, 320, 3

Excitation can be performed without destroying the resonance mode of the laminated body 520 composed of 30, 340, and as a result, high efficiency can be expected.

Further, in the present embodiment, the regions 3 15, 325, 335, and 345 which are one of the excitation region and the output region, Main surface (front and back), flat plate 3 20 main surfaces (front and back), flat plate

3 An area that is almost parallel to the two main surfaces (front and back) of 30 and the two main surfaces (front and back) of the flat plate 340, respectively, and is the other of the excitation area and the output area. 1, 323, 327, 329, 33 1, 333, 337, 339, the polarization of the two main surfaces of the plate 320 (surface, back surface) and the two main surfaces of the plate 330 (surface, Since the region is almost perpendicular to the back surface, the ratio between the input impedance and the output impedance can be increased, and as a result, the boost ratio or the buck ratio can be increased.

In the region 3 15, a circular opening 461 is provided inside the outer electrode 401 ′, and a circular electrode 40 concentric with the circular opening 461 is provided in the opening 461. 1, a circular opening 465 is provided inside the outer electrode 406 ′, and a circular electrode 406 concentric with the circular opening 465 is provided in the opening 465. 40 1, 406 and

When a voltage is applied between the electrodes 40 1 ′ and 406 ′ for polarization, the electric field intensity applied to the element during polarization becomes uniform, and the electric field intensity is radial with respect to the center of the circular electrodes 401 406. A uniform polarization process can be performed. In the region 325, a circular opening 462 is provided inside the outer electrode 4 15 ′, and a circular electrode 4 15 concentric with the circular opening 462 is provided in the opening 462. 424, a circular opening 466 is provided therein, and a circular electrode 424 concentric with the circular opening 466 is provided in the opening 466. When polarization is applied by applying a voltage between 15 5 and 424 ′, the electric field intensity applied to the element during polarization is uniform, and the center of the circular electrodes 4 15 and 424 is Radially uniform polarization processing can be performed. In the region 335, a circular opening 463 is provided inside the outer electrode 433, and the circular opening 463 is provided in the opening 463. A circular electrode 43 3 is provided concentrically with 46 3, a circular opening 46 7 is provided inside the outer electrode 44 2, and a circular opening 4 67 is provided concentrically with the circular opening 4 67. Since a circular electrode 442 is provided, when a voltage is applied between these electrodes 433, 442 and 433, 442 to be polarized, the electric field intensity applied to the element during polarization is It becomes uniform and radially uniform polarization processing can be performed on the center of the circular electrodes 4 3 3 and 442. In the region 345, a circular opening 464 is provided inside the outer electrode 45 1 ′, and a circular electrode 4 5 1 concentric with the circular opening 4 64 is provided in the opening 4 64. Since a circular opening 468 is provided inside the outer electrode 456 ′, and a circular electrode 456 concentric with the circular opening 468 is provided in the opening 468, When a voltage is applied between these electrodes 45 1, 456 and 45 1, 456 ′ to perform polarization, the electric field applied to the element during polarization becomes uniform, and a circular electrode 4 Radial and uniform polarization processing can be performed on the centers of 51 and 456.

This piezoelectric transformer can be used for both step-up and step-down applications by changing the electrical connection. Figure 41 shows the electrical connections when used for boosting. Fig. 42 shows the electrical connections when used for step-down.

(Ninth embodiment)

FIG. 43A—FIG. 43E is a diagram for explaining the piezoelectric transformer of this embodiment. FIG. 43A is a top view, FIG. 43B is a bottom view, and FIG. 43C—FIG. 43. E is a sectional view. FIG. 44 is an oblique view for explaining the piezoelectric transformer of this embodiment. FIG. FIG. 45 is a circuit diagram for explaining the electrical connection at the time of boosting of the piezoelectric transformer of the present embodiment. FIG. 46 is a circuit diagram for explaining the electrical connection of the piezoelectric transformer of the present embodiment at the time of step-down.

The flat plate 100 of the piezoelectric transformer 503 of this embodiment is made of a single plate (24 mm × 24 mm × 1 mm) of a PZT system piezoelectric ceramics. Electrodes 1-18, 5 ', 9'14', 18 'are made of Pd-Ag conductive paste. Electrode patterns are formed by screen printing electrodes 1-1,8,5,9,9,14,18 in a 3x3 grid as shown in Fig.43A and Fig.43B. I do.

Electrodes 114, 6-8, 10-13, 15-17 are square, and this square electrode shape has corners, for example, electrodes, to increase the dielectric breakdown strength between the electrodes. It is desirable that the corners 1 1 and 1 be rounded at 1, the corners 112 and 1 13 at the electrode 2, and the corners 114 at the electrode 103 be rounded. The outer shapes of the electrodes 5 ', 9', 14 'and 18' are also square. In the electrodes 5 'and 14, this square electrode shape has three corners to increase the dielectric breakdown strength. For the part, for example, electrode 5, it is desirable that the corners 115-117 are rounded.

The inside of the electrodes 5 ′, 9 ′, 14,, 18 is hollowed out in a circular shape, and circular openings 120, 122, 122, 123, respectively are formed. ing. The surface of the flat plate 100 is exposed from the openings 120 and 122, and the bottom surface of the flat plate 100 is exposed from the openings 122 and 123. Circular electrodes 5, 9, 14 and 18 are provided concentrically with the circular openings 120, 122, 122 and 123 respectively. The center of the square of the outer shape of the electrode 5 'and the center of the circular opening 1 coincide with the center of the electrode 20 and the center of the electrode 5', and the center of the square of the outer shape of the electrode 9 'and the opening of the circle The center of 1 2 2 coincides with the center of the circular electrode 9, and the outer shape of the electrode 1 4 ′ is a square center and a circular opening 1 2 1 The center of 1 and the circular electrode 1 The center of the electrode 4 coincides with the center of the circular electrode 18, and the center of the square opening and the center of the circular opening 123 coincide with the center of the circular electrode 18.

The corner 1 118 of the electrode 5 ′ is connected to the corner 1 19 of the electrode 9, and is formed as one integrated electrode 61. The electrode 61 is formed by screen-printing a conductive strip. In addition, the corners 1 18 of the electrodes 14, and the corners 1 19 ′ of the electrodes 18 are connected to each other and formed as one integrated electrode 62. The electrodes 62 are formed by screen-printing a conductive paste. As described above, the electrical connection between the two electrodes 5 ', 9 and the two electrodes 14, 14, 18' is realized by screen-printing a conductive paste. The number of parts required for connection can be reduced.

The polarization treatment is performed in oil. The polarization direction is the direction perpendicular to the two main surfaces (front and back) of the flat plate 100 as shown in Fig. 43A-Fig. 43E for the surrounding areas 101-104 and 106-108. (Z direction). As shown in FIGS. 43A and 43D, the polarization of the region 105 is radial with respect to the center of the circular electrodes 5 and 14 and is substantially flat on the main surface (front surface, back surface) of the flat plate 100. A voltage is applied between the electrode terminals B and D so that the polarization direction is in the direction of the row. Further, it is preferable that the flat plate 100 between the electrode 5 ′ and the electrode 14 be polarized in a direction perpendicular to the two main surfaces (the front surface and the back surface). As shown in FIGS. 43A and 43E, the polarization of the region 109 is radial to the center of the circular electrodes 9 and 18 and almost parallel to the main surface (front surface, back surface) of the flat plate 100. The voltage is applied between the electrode terminals B and D so that the polarization direction is oriented in the appropriate direction. The flat plate 100 between the electrode 9 ′ and the electrode 18 ′ has two main surfaces.

It is preferable to polarize in a direction perpendicular to (front and back). After the polarization process, the piezoelectric transformer element is manufactured by performing an aging process.

By doing so, the flat plate 100 having a square shape in plan view It is divided into 9 areas 1 0 1 — 1 109 in a grid of 3 x 3 divided into a total of 3 divided in the x direction and 3 divided in the y direction.

FIG. 44 shows a perspective view of the piezoelectric transformer 503 of this embodiment. The electrical connection is, for the regions 101, 103, 107, square electrodes 1, 3, 7, 10, 0, 1 located at the nodes of the piezoelectric resonance vibration of the piezoelectric transformer 503. Take out from the center of each of 2 and 16. In the regions 105 and 109, the electrode terminal portion B is taken out from the center of the circular electrode 5 and the center of the circular electrode 9 located at the node of the piezoelectric resonance vibration of the piezoelectric transformer 503. The electrode terminal D is taken out from the vicinity of the corner of the outer electrode 9 '. It is desirable to use a conductive elastic body 251-255 for electrical connection. Further, by connecting metal terminals 2 3 1 2 3 8 and 2 4 1-2 4 3 to the conductive elastic body 25 1-255 and the like, electrical connection with an external circuit is established.

In this piezoelectric transformer 503, three areas 101, 103, and 107 are arranged on the input side (or output side), and two areas are arranged on the output side (or input side). . By changing the number of areas between input and output in this way, it is possible to support various transformation ratios.

This piezoelectric transformer can be used for both step-up and step-down applications by changing the electrical connection. Figure 45 shows the electrical connections when used for boosting. Fig. 46 shows the electrical connection when used for step-down.

In this embodiment, the regions 105 and 109 are connected in parallel to be an excitation region or an output region, and the peripheral regions 101, 103 and 107 are connected in parallel. As a result, the vibration mode is aligned in both the excitation area and the output area, and it becomes possible to excite the plate 100 without breaking the resonance mode. As a result, high efficiency can be expected.

Further, in this embodiment, one of the excitation area and the output area The polarization is a region in the direction almost parallel to the two main surfaces (front and back) of the flat plate 100. The other of the excitation region and the output region is the two main surfaces of the flat plate 100 (front and back). Since the region is in a direction substantially perpendicular to the above, the ratio between the input impedance and the output impedance can be increased, and as a result, the boost ratio or the buck ratio can be increased.

In the region 105, a circular opening 120 is provided inside the outer electrode 5, and a circular electrode 5 concentric with the circular opening 120 is provided in the opening 120. In the region 109, a circular opening 122 is provided inside the outer electrode 9, and the opening 122 is concentric with the circular opening 122. Since a circular electrode 9 is provided, when a voltage is applied between these electrodes 5 and 5 'and the electrodes 9 and 9' are polarized, the electric field intensity applied to the element during polarization is reduced. It becomes uniform and radially uniform polarization processing can be performed on the centers of the circular electrodes 5 and 9 respectively. In the above-described sixth to ninth embodiments, the piezoelectric transformer having one input and one output has been described as an example. However, the piezoelectric transformer of the present invention has one input, multiple outputs, multiple inputs, one output, and multiple inputs and multiple outputs. It can be easily realized as a piezoelectric transformer of the form (1). For example, referring to FIG. 44, as an input (excitation) area, areas 101, 103 and 107 are connected in parallel to form an excitation area, and an area 105 , 106 connected in parallel to form a first output area, and areas 102, 104, 106, 108 connected in parallel to form a second output area. Can be.

In the sixth to ninth embodiments described above, for example, in the sixth embodiment, the region which is a region polarized in a direction substantially parallel to the two main surfaces (the front surface and the back surface) of the flat plate 100. In 105, a circular electrode 5 is provided on the inner side, electrodes 5 and 5 are provided on the outer side, and the inner side of the electrode 5 'is cut out in a circular shape to provide a circular opening 120. 5 and electrode 5 ' A voltage was applied to polarize between the electrode 5 and the electrode 5 ′, but only the inner electrode 5 was provided in the center of the region 105, and the outer electrode 5 ′ was not provided. It is also possible to polarize the area around electrode 5 by applying a voltage for polarization between electrodes 114, 6 and 9 of the surrounding area 10 1—10 4 and 10 5 _ 10 9 is there. As described above, according to the sixth to ninth embodiments, the output can be increased, the efficiency can be reduced, the cost can be reduced, the thickness can be reduced, and the degree of freedom in selecting the transformer ratio can be increased. A piezoelectric transformer that can be used as a transformer and that can have a large ratio of input impedance to output impedance and thus a large step-up ratio or step-down ratio can be provided. Industrial applicability

As described above, the present invention achieves high output, high efficiency, low cost, and low profile, and has a high degree of freedom in selecting a transformer ratio. Further, the present invention is applicable to a transformer with one input and multiple outputs. It can be particularly suitably used for a possible piezoelectric transformer.

Claims

The scope of the claims

1. It has two main surfaces facing each other and substantially parallel to each other, divided into m (m is an integer of 2 or more) in a first direction in the main surface, and in a second direction in the main surface. A piezoelectric transformer comprising a piezoelectric body having a plurality of regions divided in a grid pattern of n (n is an integer of 2 or more) sections in the second direction crossing a first direction,

A piezoelectric transformer, wherein at least one of the remaining areas of the plurality of areas is an output area for extracting an output from the piezoelectric transformer.

2. The piezoelectric body is a flat plate,

The excitation electrode pair is provided on the two main surfaces in the excitation region, and the output electrode pair is provided on the two main surfaces in the output region. Piezoelectric transformer.

3. An excitation electrode pair facing each other is provided substantially parallel to the two main surfaces in the excitation region,

In the output area, output electrode pairs facing each other are provided substantially parallel to the two main surfaces,

The other of the excitation electrode pair is provided on the other main surface of the two main surfaces or inside the piezoelectric body, One of the output electrode pairs is provided on one of the two main surfaces or inside the piezoelectric body,

2. The piezoelectric transformer according to claim 1, wherein the other of the pair of output electrodes is provided on the other main surface of the two main surfaces or inside the piezoelectric body.

4. The piezoelectric body is formed by stacking a plurality of flat plates made of a piezoelectric material, and the plurality of flat plates each include two sub-main surfaces substantially parallel to the two main surfaces,

The one and the other of the output electrode pairs are respectively provided on any two of the plurality of sub-main surfaces of the plurality of sub-regions stacked in the output region. 4. The piezoelectric transformer according to claim 3, wherein:

5. The piezoelectric body between the pair of excitation electrodes and the piezoelectric body between the pair of output electrodes are polarized in a direction substantially perpendicular to the two main surfaces. A piezoelectric transformer according to any one of claims 1 to 4.

6. The one of the excitation area and the output area First and second electrodes, which are one of the excitation electrode and the output electrode, are provided on the two main surfaces, respectively.

At least a part of the piezoelectric body in the other area of the excitation area and the output area is polarized so as to have a polarization component parallel to the two main surfaces. The piezoelectric transformer according to claim 1, wherein:

7. In one of the excitation area and the output area, a first electrode and a second electrode that are one of the excitation electrode and the output electrode face each other, and are disposed on the two main surfaces. A third electrode which is provided substantially in parallel with each other, and which is the other of the excitation electrode and the output electrode, is provided in the other of the excitation area and the output area; The first electrode is located on one of the two main surfaces in the one of the excitation area and the output area or the one of the excitation area and the output area. Provided inside the piezoelectric body in one region,

The piezoelectric body between the first electrode and the second electrode is polarized substantially perpendicular to the two main surfaces; At least a part of the other area of the excitation area and the output area is polarized so as to have a polarization component parallel to the two main surfaces. The piezoelectric transformer according to 1.

8. The piezoelectric body is configured by stacking a plurality of flat plates made of a piezoelectric material, and the plurality of flat plates each include two sub-main surfaces substantially parallel to the two main surfaces,

The third electrode is any one of the plurality of sub-main surfaces of the plurality of sub-regions stacked in the other of the excitation region and the output region; 8. The piezoelectric transformer according to claim 7, wherein the piezoelectric transformer is provided on the upper side.

9. At least a portion of one of the excitation region and the output region is polarized substantially perpendicular to the two main surfaces,

2. The device according to claim 1, wherein at least a part of the other of the excitation area and the output area is polarized so as to have a polarization component parallel to the two main surfaces. Piezo transformer.