JPH0974235A - Piezo-electric transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the boosting ratio of piezo-electric transformer by a method wherein a piezo-electric ceramic substrate in the region between two primary electrodes is polarized in the inverse direction to the thickness direction while another substrate between the secondary electrodes is polarized opposite to the width direction. SOLUTION: A primary electrode 61 is provided on the surface 12 of a piezo-electric ceramic substrate 10 while another primary electrode 62 is also provided on the bottom 14 of the substrate 10 so as to polarize the substrate 10 between respective primary electrodes 61 and 62 in the thickness direction between the surface 12 and the bottom 14. Here, the polarization of the substrate 10 in the region c between the primary side end 16 and the 1/3 distance of the length in the long direction of the substrate 10 and the polarization of the substrate 10 between the primary side end 16 and 2/3 distance in the long direction of the substrate 10 are mutually in the opposite directions. In such a constitution, the secondary electrodes 35, 36 are provided on the surface of the substrate 10 in the secondary side direction of the substrate 10 thereby enabling the substrate 10 between the secondary electrodes 35, 36 to be polarized in the width direction of the substrate 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric transformer, and is particularly preferably used for lighting a cold cathode fluorescent lamp (hereinafter referred to as CFL) used as a backlight of a liquid crystal display (hereinafter referred to as LCD) panel. Piezoelectric transformer.

[0002]

2. Description of the Related Art A portable device having an LCD panel such as a notebook personal computer is desired to be downsized and consume less power. The CFL widely used as the backlight of this LCD panel requires a high voltage of 1 kV or more at the start of lighting, and requires a high voltage of about several hundred V at the time of continuous lighting. A high step-up winding transformer has been used as a transformer for this purpose, but it is approaching the limit of high performance in terms of efficiency, size, and the like.

In recent years, for this LCD panel, a CFL lighting unit using a piezoelectric transformer, which is smaller and realizes high efficiency, has been developed (Nikkei Electronics, 1
994.11.7 (No. 621) pp. 147 to 1
See page 57. ). The piezoelectric transformer used here has a structure called a ROSEN type, and since the step-up ratio is still insufficient, the CFL lighting unit that has been put into practical use is provided with a winding transformer before the piezoelectric transformer. It was

FIG. 13 is a view for explaining a conventional ROSEN type piezoelectric transformer, FIG. 13A is a perspective view, and FIG.
B is a sectional view, FIG. 13C is a diagram showing a stress distribution, and FIG. 13D is a diagram showing an amplitude distribution.

A primary electrode 221 is provided on the left (primary side) half of the upper surface 12 of the rectangular parallelepiped piezoelectric ceramic substrate 10, and the piezoelectric ceramic substrate 1 faces the primary electrode 221.
The primary electrode 222 is also provided on the lower surface 14 of the piezoelectric ceramic substrate 1 between the primary electrode 221 and the primary electrode 222.
0 is polarized in the thickness direction between the upper surface 12 and the lower surface 14. Secondary side end face 1 perpendicular to the upper surface 12 and the lower surface 14
7, a secondary electrode 241 is provided, and the primary electrodes 221 and 2
Piezoelectric ceramic substrate 1 between 22 and the secondary electrode 241
0 is polarized in the longitudinal direction which is the extending direction of the upper surface 12 and the lower surface 14. One end of the power source 200 has a connecting portion 2
It is connected to the primary electrode 221 via 31 and the other end is connected to the primary electrode 222 via a connecting portion 232. The secondary electrode 241 is connected to one end of the CFL 300 as a load, and the other end of the CFL 300 is connected to the primary electrode 222 via a connection point 232.

When a voltage is applied from the power supply 200 to the primary electrodes 221, 222, an electric field is applied in the thickness direction in the left half, and longitudinal longitudinal vibration is excited by the piezoelectric lateral effect of displacement in the direction perpendicular to the polarization direction. As a result, the entire piezoelectric transformer 100 vibrates. Furthermore, in the right half, a mechanical vertical strain is generated in the longitudinal direction and a potential difference is generated in the polarization direction, so that a voltage of the same frequency as the primary voltage applied between the secondary electrode 241 and the primary electrodes 221 and 222 is extracted by the piezoelectric vertical effect. Be done.
When a drive voltage having a frequency equal to the resonance frequency of the piezoelectric transformer 100 is applied to the primary electrodes 221, 222, a very high boost ratio can be obtained.

[0007]

However, for example, PZ
To use a piezoelectric transformer made of T (lead zirconate titanate) -based ceramics as a step-up transformer of a CFL lighting inverter used in an LCD panel of an A4 size notebook personal computer, a considerably large input voltage is required. Must be applied, and the step-up ratio was still insufficient.

Therefore, an object of the present invention is to provide a piezoelectric transformer having a high boost ratio.

[0009]

According to the present invention, there is provided a substantially rectangular parallelepiped piezoelectric substrate having a first main surface and a second main surface opposed to the first main surface, In a piezoelectric transformer that uses a longitudinal vibration resonance mode of the piezoelectric substrate in a first direction, which is a direction in which one side of a first main surface extends, the resonance mode has at least one wavelength in the first direction. In a resonance mode in which a stress distribution exists, the piezoelectric substrate has a first region, a second region, and a third region in the first direction, and the first region and the second region. And the third region are regions different from each other, and the first region
Region has a half wavelength length of the stress distribution at the time of resonance in the first direction, and one of positive or negative stress is generated in the first direction at the time of resonance. A first predetermined region of the first
A first primary electrode and a second primary electrode are provided to face each other on the first main surface and the second main surface of the region, respectively, and the first primary electrode and the second primary electrode of the first region are provided. The second primary electrodes are polarized in the thickness direction between the first main surface and the second main surface, and the second region has a half of the stress distribution at the time of resonance in the first direction. A second predetermined region of the piezoelectric substrate having a length equal to or less than a wavelength and in which one of positive and negative stresses is generated in the first direction at the time of resonance, In the first major surface and the second major surface of the region of
A first electrode and a fourth primary electrode are provided to face each other, and the second region vibrates to further increase the resonance excited by the first and second primary electrodes. The third primary electrode and the fourth primary electrode in the second region are polarized in a predetermined direction according to the direction of the stress generated in the second region at the time of resonance, and the third primary electrode is polarized. The primary electrode and the fourth primary electrode are electrically connected to the first primary electrode and the second primary electrode in a predetermined connection state, and the third region has the first main surface of the first main surface. A first secondary electrode and a second secondary electrode which are opposite to each other in a second direction which is a direction in which the other side of the first main surface perpendicular to the one side extends; At least the first secondary electrode and the second secondary electrode in the region 3; The piezoelectric transformer is provided the third region between is characterized in that it is polarized in the second direction.

In the present invention, first, the first piezoelectric substrate
The first principal surface of the first region of the piezoelectric substrate having a half-wavelength length of the stress distribution at the time of resonance in which the positive or negative stress is generated in the first direction at the time of resonance And a first primary electrode and a second primary electrode are provided on the second main surface so as to face each other, and have a length equal to or less than a half wavelength of the stress distribution at resonance in the first direction and at the time of resonance. A third primary electrode and a fourth primary electrode are also provided on the first main surface and the second main surface of the second region of the piezoelectric substrate where either one of positive and negative stress is generated in the first direction. Since they are provided so as to face each other, the area of the electrode on the primary side becomes larger and the input impedance of the piezoelectric transformer becomes smaller. As a result, electric energy is easily supplied from the power supply to the piezoelectric transformer.

Further, in the present invention, the first region has a half-wavelength length of the stress distribution at resonance in the first direction of the piezoelectric substrate and has either positive or negative in the first direction at resonance. This is a region of the piezoelectric substrate in which one stress is generated, and the space between the first primary electrode and the second primary electrode in this first region is polarized in the thickness direction between the first main surface and the second main surface. The length of the second region in the first direction is equal to or less than the half-wavelength of the stress distribution at resonance, and the second region has a positive or negative value in the first direction at resonance. And a stress is generated only in one of the directions of the second main surface, and the first region of the first region is formed in the second region.
And the second region at the time of resonance so that the second region vibrates to further increase the resonance excited by the second primary electrode.
The second region is polarized in a predetermined direction in the thickness direction in accordance with the direction of the stress generated in the region, and the third primary electrode, the fourth primary electrode, the first primary electrode, and the second primary electrode. Since the primary electrode is electrically connected to the predetermined connection state, the resonance is further increased by the second region, and the input electric energy can be more efficiently converted into mechanical elastic energy on the primary side.

As described above, by providing the second region as in the present invention, the input impedance of the piezoelectric transformer is reduced, the electric energy is easily supplied from the power source to the piezoelectric transformer, and the input of the primary side is reduced. Since the electric energy can be converted into mechanical elastic energy more efficiently, the effective step-up ratio of the piezoelectric transformer can be increased.

In the present invention, the piezoelectric substrate further has a third region which is different from the first region and the second region in the first direction, and the third region has the first region. Is provided with a first secondary electrode and a second secondary electrode facing each other in a second direction which is a direction in which the other side of the main surface of the main surface of the third area perpendicular to the one side of the third area extends. At least a third region between the first secondary electrode and the second secondary electrode is polarized in the second direction. Therefore, this third
The piezoelectric substrate in the region of is coupled to the resonance in the first direction excited by the first region and the second region with Poisson's ratio, vibrates in the second direction, and is mechanically strained in the second direction. Occurs and a potential difference is generated in the polarization direction of the second direction, which can be taken out by the first and second secondary electrodes.

As described above, in the present invention, since the first and second secondary electrodes are provided so as to face each other in the second direction, the first and second secondary electrodes are the first and second secondary electrodes. In a predetermined direction, and can be extended to include a node of vibration in the first direction. Therefore, the lead wire and the lead frame from the secondary electrode can be drawn out from the nodes of the vibrations in the first direction of the first and second secondary electrodes, respectively.
As a result, electrical connection and mechanical support on the secondary side can be facilitated without disturbing vibrations in the first direction, the output of the piezoelectric transformer is stabilized, and the casing is facilitated.

Further, the first secondary electrode and the second secondary electrode in the third region on the secondary side do not share the ground potential with the primary electrode on the primary side, and therefore the circuit on the primary side. And the secondary side circuit can be separated from each other in terms of direct current, and ground electrodes independent of the primary side can be formed on the secondary side to insulate the primary side ground from the secondary side ground. ,Also,
It is also possible to float the secondary side without grounding it,
Noise resistance is also improved. On the other hand, in the conventional piezoelectric transformer shown in FIG. 13, both the primary-side and secondary-side ground electrodes are the primary electrodes 222, so that the primary-side circuit and the secondary-side circuit are connected in direct current. Could not be separated.

In order to oscillate the second region so as to further increase the resonance excited by the first and second primary electrodes in the first region, the second region is set at the time of resonance. When the direction of the generated stress is opposite to the direction of the stress generated in the first region at the time of resonance, the polarization direction between the third primary electrode and the fourth primary electrode in the second region is set to the first region. Is opposite to the polarization direction between the first primary electrode and the second primary electrode, and the third primary electrode and the first primary electrode are electrically connected to each other, and the fourth primary electrode and the second primary electrode are electrically connected. It is preferable to electrically connect the electrodes.

In order to make the second region vibrate so as to further increase the resonance excited by the first and second primary electrodes in the first region, the second region is set at the time of resonance. When the direction of the generated stress is opposite to the direction of the stress generated in the first region at the time of resonance, the polarization direction between the third primary electrode and the fourth primary electrode in the second region is preferably set to The polarization direction between the first primary electrode and the second primary electrode in the region 1 is the same, the third primary electrode and the second primary electrode are electrically connected, and the fourth primary electrode and the second primary electrode are electrically connected. 1 primary electrode is electrically connected.

Further, in order to make the second region vibrate so as to further increase the resonance excited by the first and second primary electrodes in the first region, the second region is set at the time of resonance. When the direction of the generated stress is the same as the direction of the stress generated in the first region at the time of resonance, the polarization direction between the third primary electrode and the fourth primary electrode in the second region is set to the first region. 1
The same as the polarization direction between the primary electrode and the second primary electrode, electrically connecting the third primary electrode and the first primary electrode, and electrically connecting the fourth primary electrode and the second primary electrode. It is preferable to connect them physically.

Further, a stress having a length equal to or less than a half wavelength of stress distribution at resonance in the first direction of the piezoelectric substrate and having a stress only in the same direction as the stress generated in the first region at resonance is generated at resonance. No. 4 region is further provided, and a fifth primary electrode and a sixth primary electrode are provided on the first main surface and the second main surface of the fourth region so as to face each other. The polarization direction between the fifth primary electrode and the sixth primary electrode is the same as the polarization direction between the first primary electrode and the second primary electrode in the first region, and the fifth primary electrode and the first primary electrode By electrically connecting the electrodes and electrically connecting the sixth primary electrode and the second primary electrode, the resonance excited by the first and second primary electrodes in the first region is further increased. can do.

The second region is preferably located between the first region and the third region.

When the piezoelectric substrate has the fourth region, the second region and the fourth region are preferably the first region.
It is located between the area and the third area.

Further, according to the present invention, the first main surface, the second main surface opposite to the first main surface, and the direction in which one side of the first main surface extends First orthogonal to the direction of 1
A substantially rectangular parallelepiped piezoelectric substrate having an end face and a second end face, and utilizing a longitudinal vibration resonance mode of the piezoelectric substrate in the first direction, the first and second primary electrodes are provided. Is on the first main surface and the second main surface of the piezoelectric substrate, and has a length of about ½ of the distance from the first end surface to the first end surface and the second end surface. The first and second primary electrodes and the second primary electrode, the first and second primary electrodes and the second primary electrode extending in the first direction, respectively.
On the first main surface and the second main surface of a predetermined region of the piezoelectric substrate between the first and second primary electrodes, and the third and fourth primary electrodes are spaced apart from each other. Electrodes are provided respectively, and the piezoelectric substrate between the first primary electrode and the second primary electrode is polarized in a thickness direction between the first main surface and the second main surface, and the third substrate is provided. The piezoelectric substrate between the primary electrode and the fourth primary electrode is polarized in the thickness direction in the same direction as the polarization direction of the piezoelectric substrate between the first primary electrode and the second primary electrode, Primary electrode and the first primary electrode are electrically connected, the third primary electrode and the second primary electrode are electrically connected, and the third and fourth primary electrodes and the second primary electrode are electrically connected. A predetermined area between the end surface of the piezoelectric substrate and the one side of the first main surface. A first secondary electrode and a second secondary electrode facing each other in a second direction, which is a direction in which the other side of the first main surface at a right angle extends, are provided, and the first secondary electrode is provided. A piezoelectric transformer is provided, characterized in that the piezoelectric substrate between a secondary electrode and the second secondary electrode is polarized in the second direction.

This piezoelectric transformer is preferably applied to a piezoelectric transformer having a stress distribution of one wavelength in the first direction between the first end face and the second end face, and can increase the boosting ratio,
Further, the circuit on the primary side and the circuit on the secondary side can be separated in terms of direct current, and the noise resistance is also improved.

Further, according to the present invention, the first main surface, the second main surface facing the first main surface, and the direction in which one side of the first main surface extends First orthogonal to the direction of 1
A substantially rectangular parallelepiped piezoelectric substrate having an end face and a second end face, and utilizing a longitudinal vibration resonance mode of the piezoelectric substrate in the first direction, the first and second primary electrodes are provided. Is a length of about 1/3 of the distance between the first end surface and the second end surface on the first main surface and the second main surface of the piezoelectric substrate. A third primary electrode and a fourth primary electrode, each of which extends in the first direction to a position at a distance of, and has the first and second main surfaces of the piezoelectric substrate. 1
From the end surface of the first end surface to the second end surface at a distance of about 1/3 of the distance from the first end surface to the first end surface and the second end surface. And a distance of about 2/3 of the distance between the first and second primary electrodes and the secondary electrode, each extending in the first direction. The piezoelectric substrate between the first primary electrode and the second primary electrode is polarized in the thickness direction between the first main surface and the second main surface, and the piezoelectric substrate is connected to the third primary electrode and the third primary electrode. The piezoelectric substrate between the fourth primary electrodes is polarized in the thickness direction in the same direction as the polarization direction of the piezoelectric substrate between the first primary electrode and the second primary electrode, and the fourth primary electrode and The first primary electrode is electrically connected and the third primary electrode and the second primary are The poles are electrically connected to each other, and the first region perpendicular to the one side of the first main surface is provided in a predetermined region of the piezoelectric substrate between the third and fourth primary electrodes and the second end face. A first secondary electrode and a second secondary electrode facing each other in a second direction, which is a direction in which the other side of the main surface extends, and the first secondary electrode and the second secondary electrode are provided. A piezoelectric transformer is provided, characterized in that the piezoelectric substrate between two secondary electrodes is polarized in the second direction.

This piezoelectric transformer is suitably applied to a piezoelectric transformer having a stress distribution of 1.5 wavelengths in the first direction between the first end face and the second end face, and the step-up ratio can be increased, In addition, the electrical connection and mechanical support on the secondary side can be easily performed without disturbing the vibration in the first direction, the output of the piezoelectric transformer is stabilized, and the casing is facilitated. It is possible to separate the side circuit and the secondary side circuit in terms of direct current, and the noise resistance is also improved.

In this case, the third and fourth primary electrodes and the first and second secondary electrodes are provided with the third and third regions on the first and second main faces of the predetermined region of the piezoelectric substrate. And spaced apart from the fourth primary electrode and the first and second secondary electrodes,
Fifth and sixth primary electrodes are further provided, respectively, and
The piezoelectric substrate between the first primary electrode and the sixth primary electrode is polarized in the thickness direction in the same direction as the polarization direction of the piezoelectric substrate between the first primary electrode and the second primary electrode. By electrically connecting the primary electrodes of, and electrically connecting the sixth primary electrode and the second primary electrode, a piezoelectric transformer having a higher boosting ratio can be obtained.

Further, according to the present invention, the first main surface, the second main surface facing the first main surface, and the direction in which one side of the first main surface extends First orthogonal to the direction of 1
A substantially rectangular parallelepiped piezoelectric substrate having an end face and a second end face, and utilizing a longitudinal vibration resonance mode of the piezoelectric substrate in the first direction, the first and second primary electrodes are provided. Is on the first main surface and the second main surface of the piezoelectric substrate, and has a length of about ½ of the distance from the first end surface to the first end surface and the second end surface. The first and second primary electrodes and the second primary electrode, the first and second primary electrodes and the second primary electrode extending in the first direction, respectively.
On the first main surface and the second main surface of a predetermined region of the piezoelectric substrate between the first and second primary electrodes, and the third and fourth primary electrodes are spaced apart from each other. Electrodes are provided respectively, and the piezoelectric substrate between the first primary electrode and the second primary electrode is polarized in a thickness direction between the first main surface and the second main surface, and the third substrate is provided. The piezoelectric substrate between the primary electrode and the fourth primary electrode is polarized in the thickness direction in a direction opposite to the polarization direction of the piezoelectric substrate between the first primary electrode and the second primary electrode, Primary electrode and the first primary electrode are electrically connected, the fourth primary electrode and the second primary electrode are electrically connected, and the third and fourth primary electrodes and the second primary electrode are electrically connected. A predetermined area between the end surface of the piezoelectric substrate and the one side of the first main surface. A first secondary electrode and a second secondary electrode facing each other in a second direction, which is a direction in which the other side of the first main surface at a right angle extends, are provided, and the first secondary electrode is provided. A piezoelectric transformer is provided, characterized in that the piezoelectric substrate between a secondary electrode and the second secondary electrode is polarized in the second direction.

This piezoelectric transformer is preferably applied to a piezoelectric transformer in which a stress distribution of one wavelength exists in the first direction between the first end face and the second end face, and the step-up ratio can be increased,
Further, the circuit on the primary side and the circuit on the secondary side can be separated in terms of direct current, and the noise resistance is also improved.

Further, according to the present invention, the first main surface, the second main surface facing the first main surface, and the direction in which one side of the first main surface extends First orthogonal to the direction of 1
A substantially rectangular parallelepiped piezoelectric substrate having an end face and a second end face, and utilizing a longitudinal vibration resonance mode of the piezoelectric substrate in the first direction, the first and second primary electrodes are provided. Is a length of about 1/3 of the distance between the first end surface and the second end surface on the first main surface and the second main surface of the piezoelectric substrate. A third primary electrode and a fourth primary electrode, each of which extends in the first direction to a position at a distance of, and has the first and second main surfaces of the piezoelectric substrate. 1
From the end surface of the first end surface to the second end surface at a distance of about 1/3 of the distance from the first end surface to the first end surface and the second end surface. And a distance of about 2/3 of the distance between the first and second primary electrodes and the secondary electrode, each extending in the first direction. The piezoelectric substrate between the first primary electrode and the second primary electrode is polarized in the thickness direction between the first main surface and the second main surface, and the piezoelectric substrate is connected to the third primary electrode and the third primary electrode. The piezoelectric substrate between the fourth primary electrodes is polarized in the thickness direction in a direction opposite to the polarization direction of the piezoelectric substrate between the first primary electrode and the second primary electrode, and the third primary electrode and The first primary electrode is electrically connected to the fourth primary electrode and the second primary electrode. The poles are electrically connected to each other, and the first region perpendicular to the one side of the first main surface is provided in a predetermined region of the piezoelectric substrate between the third and fourth primary electrodes and the second end face. A first secondary electrode and a second secondary electrode facing each other in a second direction, which is a direction in which the other side of the main surface extends, and the first secondary electrode and the second secondary electrode are provided. A piezoelectric transformer is provided, characterized in that the piezoelectric substrate between two secondary electrodes is polarized in the second direction.

This piezoelectric transformer is suitably applied to a piezoelectric transformer having a stress distribution of 1.5 wavelengths in the first direction between the first end face and the second end face, and can increase the boost ratio, In addition, the electrical connection and mechanical support on the secondary side can be easily performed without disturbing the vibration in the first direction, the output of the piezoelectric transformer is stabilized, and the casing is facilitated. It is possible to separate the side circuit and the secondary side circuit in terms of direct current, and the noise resistance is also improved.

In this case, the third and fourth primary electrodes and the first and second secondary electrodes are provided with the third and third regions on the first and second main faces in predetermined regions of the piezoelectric substrate. And spaced apart from the fourth primary electrode and the first and second secondary electrodes,
Fifth and sixth primary electrodes are further provided, respectively, and
The piezoelectric substrate between the first primary electrode and the sixth primary electrode is polarized in the thickness direction in the same direction as the polarization direction of the piezoelectric substrate between the first primary electrode and the second primary electrode. A piezoelectric transformer having a higher step-up ratio can be obtained by electrically connecting the primary electrodes of, and electrically connecting the sixth primary electrode and the second primary electrode.

The first secondary electrode is provided on one end face of the third end face and the fourth end face orthogonal to the second direction of the piezoelectric substrate, and the second secondary electrode of the piezoelectric substrate is provided. It may be provided on the other end face of the third end face and the fourth end face.

Further, it is preferable that the first and second secondary electrodes are both provided on one of the first main surface and the second main surface of the piezoelectric substrate. In this way, the secondary electrode can be formed at the same time as the primary electrode in one film forming process. Furthermore, the connection with the lead or the lead frame is only on the first and second main surfaces,
The lead or lead frame shape can be simplified.

Further, the first secondary electrode is provided on one of the first main surface and the second main surface of the piezoelectric substrate, and the second secondary electrode is provided on the first main surface of the piezoelectric substrate. It is also preferable to provide it on the other main surface of the main surface and the second main surface. Even in this case, the secondary electrode can be formed at the same time as the primary electrode in each film forming process on each main surface. Furthermore, the connection with the lead or the lead frame is only on the first and second main surfaces, and the shape of the lead or the lead frame can be simplified.

It is preferable to provide the support portion of the piezoelectric transformer at the position of the node in the first direction of vibration in the resonance mode of the piezoelectric transformer. With this configuration, even if the supporting portion of the piezoelectric transformer is provided, the vibration of the piezoelectric transformer is not hindered and the reduction of the conversion efficiency can be prevented.

Further, it is preferable to provide an electrical connection point to the primary electrode of the piezoelectric transformer and an electrical connection point to the secondary electrode thereof at the nodes of the vibration in the resonance mode of the piezoelectric transformer in the first direction. With this configuration, even if the electrical connection point to the piezoelectric transformer is provided, the vibration of the piezoelectric transformer is not hindered and the conversion efficiency can be prevented from lowering.

If the lead wire or the lead frame, especially the lead frame, is pulled out from the node position of the piezoelectric transformer, electrical connection and mechanical support can be performed at the node position at the same time. Particularly, in the present invention, since the first and second secondary electrodes are provided so as to face each other in the second direction, these first and second secondary electrodes are arranged in a predetermined direction in the first direction. It will extend in length and will be able to extend to include nodes of vibration in the first direction. Therefore, the lead wire and the lead frame from the secondary electrode can be extracted from the nodes of the vibrations of the first and second secondary electrodes in the first direction, respectively, and as a result, the first The electrical connection and mechanical support of the secondary side can be easily performed without disturbing the directional vibration.
The output of the piezoelectric transformer is stable and the casing is easy.

The piezoelectric transformer of the present invention is preferably used as a piezoelectric transformer for lighting a cold cathode tube.

The piezoelectric transformer of the present invention is preferably incorporated in an inverter.

The piezoelectric transformer of the present invention is preferably incorporated in a liquid crystal display.

Furthermore, the piezoelectric transformer of the present invention is
It is also suitably used for a high voltage circuit for deflecting a cathode ray tube, a high voltage generating circuit for a copying machine, a facsimile or the like.

The piezoelectric material used as the piezoelectric substrate in the present invention is, for example, a PZT system or
PbTiO ₃ -based piezoelectric ceramics such as PbTiO ₃ are used. Examples of PZT ceramics include PZT, Pb (Ni _1/3 Nb _2/3 ) O ₃ -Pb (Z
n _1/3 Nb _2/3 ) O ₃ -PbTiO ₃ -PbZrO ₃ ceramics.

Examples of the electrode material used in the present invention include Ag and Ag-Pd.

[0044]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

(First Embodiment) FIG. 1 is a diagram for explaining a piezoelectric transformer according to the first embodiment.
Is a perspective view, FIG. 1B is a sectional view, FIG. 1C is a view showing stress distribution, and FIG. 1D is a view showing amplitude distribution.

As shown in FIGS. 1A and 1B, the primary electrode 21 is provided on the left side 1/3 of the upper surface 12 of the rectangular parallelepiped piezoelectric ceramic substrate 10, and the lower surface 14 of the piezoelectric ceramic substrate 10 is opposed to the primary electrode 21. Is also provided with a primary electrode 22, and the piezoelectric ceramic substrate 10 between the primary electrode 21 and the primary electrode 22 is polarized in the thickness direction between the upper surface 12 and the lower surface 14.

On the upper surface 12 of the piezoelectric ceramic substrate 10, from the position separated from the primary side end surface 16 by a distance ⅓ of the length of the piezoelectric ceramic substrate 10 in the longitudinal direction, the piezoelectric ceramic substrate 10 extends from the primary side end surface 16 to the longitudinal direction. The primary electrode 23 is provided up to a position spaced apart by ⅔ of the length in the direction, and the primary electrode 24 is also provided on the lower surface 14 of the piezoelectric ceramic substrate 10 so as to face the primary electrode 23. The primary electrode 23 is provided apart from the primary electrode 21, and the primary electrode 24 is provided apart from the primary electrode 22. The piezoelectric ceramic substrate 10 between the primary electrode 23 and the primary electrode 24 is polarized in the thickness direction between the upper surface 12 and the lower surface 14. The polarization direction of the piezoelectric ceramics substrate 10 between the primary electrodes 21 and 22 and the polarization direction of the piezoelectric ceramics substrate 10 between the primary electrodes 23 and 24 are the same.

The widthwise end face 18 in the width direction perpendicular to the longitudinal direction of the piezoelectric ceramic substrate 10 has a secondary end face 1
7, the secondary side end surface 17 to the piezoelectric ceramic substrate 10
To a position separated by a distance less than 1/3 of the length in the longitudinal direction of
The secondary electrode 31 is provided, and the secondary electrode 3 faces the secondary electrode 31 and also on the end surface 19 in the width direction of the piezoelectric ceramic substrate 10.
2 are provided. The secondary electrode 31 is provided with a predetermined distance from the primary electrodes 23 and 24, and the secondary electrode 32 is also provided with a predetermined distance from the primary electrodes 23 and 24. The piezoelectric ceramic substrate 10 between the secondary electrode 31 and the secondary electrode 32 is polarized in the width direction between the secondary end surface 18 and the secondary end surface 19.

One end of the power source 200 is connected to the primary electrode 21 via the connecting portion 51, and the primary electrode 2 is connected via the connecting portion 54.
It is connected with 4. The other end of the power source 200 is connected to the primary electrode 22 via the connecting portion 52, and is connected to the primary electrode 23 via the connecting portion 53.

The secondary electrode 31 is connected to one end of the CFL 300 as a load via the connecting portion 55, and the other end of the CFL 300 is connected to the secondary electrode 32 via the connecting portion 56.

When a voltage is applied between the primary electrodes 21 and 22 from the power supply 200, an electric field is applied in the thickness direction in the left third region, and the piezoelectric lateral effect causes displacement in the direction perpendicular to the polarization direction. The longitudinal vibration of the piezoelectric transformer 1
The whole 00 vibrates. The piezoelectric transformer of the present embodiment is driven in a resonance mode in which a stress distribution of 1.5 wavelength exists between the primary side end face 16 and the secondary side end face 17. Power supply 20
From 0, a voltage having a frequency equal to the resonance frequency of the 1.5 wavelength type mode is applied. In the present embodiment, the support points are provided at the location X away from the primary side end surface 16 to the right by the distance of 1/6 wavelength and at the location Z away from the secondary side end surface 17 to the left of the 1/6 wavelength. Piezoelectric ceramics substrate 1
Since both the primary side end surface 16 and the secondary side end surface 0 of 0 are open, the stress becomes zero and the amplitude becomes maximum at both ends in the longitudinal direction of the piezoelectric ceramic substrate 10. Since the resonance is performed in the 1.5 wavelength mode in the present embodiment, the stress distribution and the amplitude distribution are as shown in FIGS. 1C and 1D, respectively.

When driven in such a 1.5-wavelength mode, the vibration node is located at a distance of 1/6 from the primary side end surface 16 of the piezoelectric ceramic substrate 10 (node X), and the primary side end surface of the piezoelectric ceramic substrate 10. There are three locations, a distance of 16 to 1/2 (node Y) and a distance of 5/6 from the primary side end surface 16 of the piezoelectric ceramic substrate 10 (node Z).

In this embodiment, the primary electrode 21,
In addition to 22, primary electrodes 23 and 24 are further provided. Therefore, the electrode area on the primary side is increased, and the input impedance of the piezoelectric transformer 100 is decreased accordingly. As a result, the piezoelectric transformer 100 is connected to the power source 20.
Electric energy is easily supplied from 0.

The stress in the region where the primary electrodes 21 and 22 are provided is in the direction of the upper surface 12 of the piezoelectric ceramic substrate 10, whereas the stress in the region where the primary electrodes 23 and 24 are provided is piezoelectric. The direction is the lower surface of the ceramic substrate 10 and the direction opposite to the stress in the region where the primary electrodes 21 and 22 are provided. Primary electrode 23 and primary electrode 2
The polarization direction of the piezoelectric ceramics substrate 10 between the electrodes 4 and 4 is the same as the polarization direction of the piezoelectric ceramics substrate 10 between the primary electrode 21 and the primary electrode 22, but the application direction of the electric field is the opposite direction. Therefore, from the power source 200 to the primary electrode 23,
When a voltage is applied between 24, the piezoelectric ceramic substrate 10 between the primary electrodes 23 and 24 further increases resonance excited by the voltage applied from the power supply 200 to the primary electrodes 21 and 22. Vibrate. As a result, the electrical energy supplied from the power supply 200 on the primary side can be converted into mechanical elastic energy more efficiently.

As described above, the primary electrodes 23 and 24 are provided in the regions where the stress is generated in the direction opposite to the stress in the regions where the primary electrodes 21 and 22 are provided, and the primary electrode 23 and the primary electrode 2 are provided.
4, the piezoelectric ceramic substrate 10 is polarized in the same direction as the piezoelectric ceramic substrate 10 between the primary electrodes 21 and 22, and the electric field is applied in the opposite direction. Since the input impedance of the
Since the electric energy can be easily supplied from 0 and the input electric energy can be more efficiently converted into mechanical elastic energy on the primary side, the effective step-up ratio of the piezoelectric transformer 100 can be increased.

Further, in the present embodiment, the secondary electrode 3 is formed on the end face 18 in the width direction of the piezoelectric ceramic substrate 10.
1 is provided, the secondary electrode 32 is also provided on the widthwise end face 19 of the piezoelectric ceramic substrate 10 facing the secondary electrode 31, and the piezoelectric ceramic substrate 10 between the secondary electrode 31 and the secondary electrode 32 is It is polarized in the width direction between the secondary side end surface 18 and the secondary side end surface 19. Therefore, the piezoelectric ceramic substrate 1 between the secondary electrode 31 and the secondary electrode 32 is
0 is the piezoelectric ceramic substrate 1 between the primary electrodes 21 and 22.
0 and the resonance in the longitudinal direction excited by the piezoelectric ceramic substrate 10 between the primary electrodes 23 and 24 and the Poisson's ratio are coupled to cause vibration in the width direction and mechanical strain occurs in the width direction to cause polarization in the width direction. Since a potential difference is generated, it can be taken out by the secondary electrodes 31 and 32.

Further, in this way, the secondary electrode 3 is provided on the secondary side.
Since the primary electrode 21 and the secondary electrode 32 are provided independently of the primary electrodes 21 to 24 in terms of direct current, it becomes possible to separate the primary side circuit and the secondary side circuit in terms of direct current. Ground electrodes that are independent of the primary side are formed on the secondary side (for example, the primary electrodes 22 and 23 and the secondary electrode 31 are independent ground electrodes), and the ground of the primary side and the ground of the secondary side are formed. Can be insulated, and the secondary side can be floated without being grounded (for example, the secondary electrode 31 can be floated without being grounded), and noise resistance is also improved.

Further, in the present embodiment, since the secondary electrodes 31 and 32 are provided so as to face each other in the width direction of the piezoelectric ceramic substrate 10, these secondary electrodes 31 and 32 are piezoelectric ceramic substrates. 10 has a predetermined length in the longitudinal direction, and has a node Z of vibration in the longitudinal direction.
Has been extended to include. Therefore, the lead wires and the lead frame from the secondary electrodes 31 and 32 can be drawn out from the portions of the longitudinal ceramic vibration node Z of the piezoelectric ceramic substrate 10, respectively, and as a result, the longitudinal vibration is impeded. Without the need for electrical connection and mechanical support on the secondary side, the piezoelectric transformer 10
The output of 0 becomes stable and the casing becomes easy.

In the present embodiment, since the vibration nodes X and Z are used as the support points of the piezoelectric transformer 100, the inhibition of the vibration of the piezoelectric transformer 100 caused by supporting the piezoelectric transformer 100 is made extremely small. be able to. Furthermore, in the present embodiment, the primary electrode 21,
22 connection points 51, 52 and these connection points 51, 5
The electrode terminal provided in 2 is also provided in the vibration node X, and the primary electrode 2
3, 24 connection points 53, 54 and these connection points 5
Since the electrode terminals provided at 3, 54 are also provided at the vibration node Y, and the connection points 55, 56 of the secondary electrodes 31, 32 and the electrode terminals provided at these connection points 55, 56 are also provided at the vibration node Z, It is also possible to prevent the vibration from being hindered by the electrical connection portion.

(Second Embodiment) FIG. 2 is a perspective view of a piezoelectric transformer according to a second embodiment. In the first embodiment, the secondary electrodes 31 and 32 are provided on the end faces 18 and 19 in the width direction of the piezoelectric ceramic substrate 10, respectively. However, in the present embodiment, the secondary electrodes 33 and 34 are
The width direction end surface 18 of the upper surface 12 of the piezoelectric ceramic substrate 10
Side and the end face 19 in the width direction, the piezoelectric ceramic substrate 1
0 from the secondary side end surface 17 to the secondary side end surface 17 so as to face each other in the width direction of 0.
0 is different from the first embodiment in that it is provided up to a position separated by a distance of a little less than 1/3 of the length in the longitudinal direction, but the other points are the same, and the secondary electrode 33 and the secondary electrode are similar. The point where the piezoelectric ceramics substrate 10 between 34 and 34 is polarized in the width direction of the piezoelectric ceramics substrate 10, and the connection points 57 and 58 between the secondary electrodes 33 and 34 and the electrode terminals are defined in the longitudinal direction of the piezoelectric ceramics substrate 10. Vibration node Z
Similarly, the support point on the secondary side of the piezoelectric transformer 100 is also provided at the node Z of vibration in the longitudinal direction of the piezoelectric ceramic substrate 10.

In this embodiment, the secondary electrode 33,
Since both 34 are provided on the upper surface 12 of the piezoelectric ceramic substrate 10, the secondary electrodes 33, 34 can be formed in the same film forming process as the primary electrodes 21, 23. Further, the connection with the lead or the lead frame is made only on the upper surface 12 and the lower surface 14, so that the shape of the lead or the lead frame can be simplified.

(Third Embodiment) FIG. 3 is a diagram for explaining a piezoelectric transformer according to a third embodiment of the present invention. FIG. 3A is a perspective view, FIG. 3B is a sectional view, and FIG. 3C. Is a diagram showing a stress distribution, and FIG. 3D is a diagram showing an amplitude distribution.

As shown in FIGS. 3A and 3B, a primary electrode 61 is provided in a region ⅔ on the left side of the upper surface 12 of the rectangular parallelepiped piezoelectric ceramic substrate 10, and the primary electrode 61 is provided so as to face the piezoelectric ceramic substrate 10. A primary electrode 62 is also provided on the lower surface 14, and the piezoelectric ceramic substrate 10 between the primary electrode 61 and the primary electrode 62 (primary side region a) is polarized in the thickness direction between the upper surface 12 and the lower surface 14. However, the piezoelectric ceramic substrate 10 between the primary-side end surface 16 and the distance from the primary-side end surface 16 to the distance of 1/3 of the longitudinal length of the piezoelectric ceramic substrate 10 (region c) is polarized downward, and The distance from the end face 16 to the distance of ⅓ of the length of the piezoelectric ceramic substrate 10 in the longitudinal direction and the end face 1 on the primary side
6 to 2 of the length of the piezoelectric ceramic substrate 10 in the longitudinal direction.
The piezoelectric ceramics substrate 10 between the distance of / 3 and the region (region d) is polarized upward, and the piezoelectric ceramics substrate 10 in the region c and the piezoelectric ceramics substrate 1 in the region d are polarized.
Zero polarization is in the opposite direction.

Primary end face 1 of piezoelectric ceramic substrate 10
6 to 2 of the length of the piezoelectric ceramic substrate 10 in the longitudinal direction.
The secondary electrode 35, at the width direction end surface 18 side and the width direction end surface 19 side of the upper surface 12 of the piezoelectric ceramic substrate 10 between the distance / 3 and the secondary side end surface 17 (secondary side region b). Three
6 from the secondary side end surface 17 to the secondary side end surface 1 so that they face each other in the width direction of the piezoelectric ceramic substrate 10.
7 to 1 of the length of the piezoelectric ceramic substrate 10 in the longitudinal direction.
They are provided up to the positions separated by a distance of a little less than / 3. The secondary electrode 35 is provided at a predetermined distance from the primary electrodes 61 and 62, and the secondary electrode 36 is also provided at a predetermined distance from the primary electrodes 61 and 62. The piezoelectric ceramic substrate 10 between the secondary electrode 33 and the secondary electrode 34 is polarized in the width direction of the piezoelectric ceramic substrate 10.

One end of the power source 200 is connected to the primary electrode 61 via the connecting portion 71, and the other end of the power source 200 is connected to the connecting portion 72.
Is connected to the primary electrode 62 via.

The secondary electrode 35 is connected to one end of the CFL 300 as a load via the connecting portion 73, and the other end of the CFL 300 is connected to the secondary electrode 36 via the connecting portion 74.

When a voltage is applied between the primary electrodes 61 and 62 from the power supply 200, the left 2/3 region (primary side region a).
Then, an electric field is applied in the thickness direction, and the longitudinal vibration in the longitudinal direction is excited by the piezoelectric lateral effect of displacement in the direction perpendicular to the polarization direction, and the entire piezoelectric transformer 100 vibrates. The piezoelectric transformer of the present embodiment is driven in a resonance mode in which a stress distribution of 1.5 wavelength exists between the primary side end face 16 and the secondary side end face 17. A voltage having a frequency equal to the resonance frequency of the 1.5 wavelength mode is applied from the power supply 200. In the present embodiment, since both the primary side end surface 16 and the secondary side end surface 17 of the piezoelectric ceramic substrate 10 are open, the stress becomes zero and the amplitude becomes maximum at both ends of the piezoelectric ceramic substrate 10 in the longitudinal direction. Become. And
In the present embodiment, since resonance is performed in the 1.5 wavelength mode, the stress distribution and the amplitude distribution are as shown in FIGS. 3C and 3D, respectively.

When driven in such a 1.5-wavelength mode, the vibration node is located at a distance of 1/6 from the primary-side end surface 16 of the piezoelectric ceramic substrate 10 (node X), and the primary-side end surface of the piezoelectric ceramic substrate 10. There are three locations, a distance of 16 to 1/2 (node Y) and a distance of 5/6 from the primary side end surface 16 of the piezoelectric ceramic substrate 10 (node Z). In the present embodiment, the connecting portions 71 and 72 are provided at the vibration node X, and the connecting portions 73 and 74 are provided at the vibration node Z.

In this embodiment, the primary electrode 61,
62 extends from the primary-side end surface 16 to a position at a distance of ⅔ of the length of the piezoelectric ceramic substrate 10 in the longitudinal direction from the primary-side end surface 16. Therefore, the electrode area on the primary side is increased, and the input impedance of the piezoelectric transformer 100 is decreased accordingly. As a result, electric energy is easily supplied to the piezoelectric transformer 100 from the power supply 200.

The stress in the region c is in the direction of the upper surface 12 of the piezoelectric ceramics substrate 10, whereas the stress in the region d is in the direction of the lower surface of the piezoelectric ceramics substrate 10 and in the opposite direction to the stress in the region c. Is. The polarization direction of the region c is
Although the polarization direction of the region d is opposite, the application direction of the electric field is the same direction. Therefore, from the power source 200 to the primary electrode 61,
When a voltage is applied between 62, the piezoelectric ceramic substrate 10 in the region d vibrates so as to further increase the resonance excited by the voltage applied from the power source 200 to the region c. As a result, the electrical energy supplied from the power supply 200 on the primary side can be converted into mechanical elastic energy more efficiently.

As described above, in the present embodiment, in the primary side region a, the primary electrodes 61 and 62 are extended to the region d where the stress in the direction opposite to the stress in the region c is generated,
By making the polarization direction of the region c different from the polarization direction of the region d and making the direction of applying the electric field the same, the input impedance of the piezoelectric transformer 100 is reduced, and the piezoelectric transformer 100 is supplied with electric energy from the power source 200. In addition, since the input electric energy can be more efficiently converted into mechanical elastic energy in the primary region a, the effective boosting ratio of the piezoelectric transformer 100 can be increased.

Further, in the present embodiment, the secondary electrodes 35, 3 are provided on the width direction end face 18 side and the width direction end face 19 side of the upper surface 12 of the piezoelectric ceramic substrate 10 in the secondary side region b.
6 from the secondary side end surface 17 to the secondary side end surface 1 so that they face each other in the width direction of the piezoelectric ceramic substrate 10.
7 to 1 of the length of the piezoelectric ceramic substrate 10 in the longitudinal direction.
The piezoelectric ceramic substrates 10 provided respectively up to the positions separated by a distance of a little less than / 3 and between the secondary electrodes 33 and 34 are polarized in the width direction of the piezoelectric ceramic substrate 10. Therefore, the secondary electrode 35 and the secondary electrode 3 are
The piezoelectric ceramic substrate 10 between the first electrode 6 and the
The resonance between the piezoelectric ceramic substrate 10 and the piezoelectric ceramic substrate 10 between 1 and 62 in the longitudinal direction is coupled with the Poisson's ratio to vibrate in the width direction of the piezoelectric ceramic substrate 10 to cause mechanical strain in the width direction. A potential difference is generated in the polarization direction in the width direction.
5, 36 can be taken out.

As described above, the secondary electrode 3 is provided on the secondary side.
Since the DC electrode 5 and the secondary electrode 36 are provided independently of the primary electrodes 61 and 62 in terms of direct current, it is possible to separate the primary side circuit and the secondary side circuit in terms of direct current. An independent ground electrode is formed on the secondary side from the primary side (for example, the primary electrode 62 and the secondary electrode 35 are independent ground electrodes) to insulate the primary side ground from the secondary side ground. It is also possible to float the secondary side without grounding (for example, to float the secondary electrode 35 without grounding), and improve the noise resistance.

Further, in the present embodiment, since the secondary electrodes 35 and 36 are provided so as to face each other in the width direction of the piezoelectric ceramic substrate 10, these secondary electrodes 35 and 36 are provided on the piezoelectric ceramic substrate. 10 has a predetermined length in the longitudinal direction, and has a node Z of vibration in the longitudinal direction.
Has been extended to include. Therefore, the lead wires and the lead frame from the secondary electrodes 35 and 36 can be drawn out from the portions of the longitudinal ceramic vibration node Z of the piezoelectric ceramic substrate 10, respectively, and as a result, the longitudinal vibration is hindered. Without the need for electrical connection and mechanical support on the secondary side, the piezoelectric transformer 10
The output of 0 becomes stable and the casing becomes easy.

Furthermore, in the present embodiment,
Since the secondary electrodes 35 and 36 are both provided on the upper surface 12 of the piezoelectric ceramic substrate 10, the secondary electrodes 35 and 36 can be formed in the same film forming process as the primary electrode 61. Furthermore, the connection with the lead or the lead frame is the upper surface 12 and the lower surface 1.
4 only, the shape of the lead or lead frame can be simplified.

In the present embodiment as well, since the vibration nodes X and Z are set as the supporting points of the piezoelectric transformer 100, the inhibition of the vibration of the piezoelectric transformer 100 caused by supporting the piezoelectric transformer 100 is made extremely small. be able to. Furthermore, also in this embodiment, the primary electrode 61,
62 connection points 71, 72 and these connection points 71, 7
The electrode terminal provided in 2 is also provided in the vibration node X, and the secondary electrode 3
5, 36 connection points 73, 74 and these connection points 7
Since the electrode terminals provided on 3, 74 are also provided on the vibration node Z,
It is possible to prevent the vibration from being hindered by the electrical connection portion.

Next, a method of manufacturing the piezoelectric transformer 100 of the present embodiment will be described with reference to FIG.

In this embodiment, the upper surface 1 of the region c of the piezoelectric ceramic substrate 10 is formed by screen printing or the like.
2, a primary electrode 63 on the lower surface 14 of the area c of the piezoelectric ceramic substrate 10, a primary electrode 64 on the upper surface 12 of the area d of the piezoelectric ceramic substrate 10, and a primary electrode 65 on the area d of the piezoelectric ceramic substrate 10. A primary electrode 66 is formed on the lower surface 14, and secondary electrodes 35 and 36 are formed on the upper surface 12 in the secondary region b of the piezoelectric ceramic substrate 10.

After that, the primary electrodes 63 and 64 are connected to a high-voltage DC power supply (not shown) for polarization, and the primary electrode 6
5 and 66 are connected to another high-voltage DC power supply (not shown) for polarization, and a high voltage is applied from each high-voltage DC power supply to polarize the c region and the d region in the thickness direction.

On the other hand, the secondary electrodes 35 and 36 are connected to a high-voltage DC power supply (not shown) for polarization, and a high voltage is applied to polarize the piezoelectric ceramic substrate 10 in the secondary region b in the width direction. Perform processing.

Thereafter, the conductive paste 67 connects the primary electrodes 63 and 65 to form the primary electrode 61 shown in FIG. 3, and the conductive paste 68 connects the primary electrodes 64 and 66 to the primary electrode 61 shown in FIG. The primary electrode 62 was used.

Thereafter, as shown in FIG. 3, one end of the power source 200 is connected to the primary electrode 61 via the connecting portion 71, and the other end of the power source 200 is connected to the primary electrode 62 via the connecting portion 72. The secondary electrode 35 is connected to one end of the CFL 300 via the connecting portion 73, and the other end of the CFL 300 is connected to the secondary electrode 36 via the connecting portion 74.

FIG. 5 is a perspective view for explaining a method of mounting the piezoelectric transformer of this embodiment.

The piezoelectric transformer 100 includes the lead frame 8
It is supported by 1, 82, 83 and 84. The lead frames 82 and 83 are supported by the support portion 91, and the lead frames 81 and 84 are supported by the support portion 92. The vicinity of one end of the lead frame 81 is connected and fixed to the primary electrode 61 by welding at the connecting portion 71. The connection portion 72 is provided near one end of the lead frame 82.
At, it is connected and fixed to the primary electrode 62 by welding. The vicinity of one end of the lead frame 83 is connected and fixed to the secondary electrode 35 by welding at the connecting portion 73, and the vicinity of one end of the lead frame 84 is connected and fixed to the secondary electrode 36 by welding at the connecting portion 74. Connection parts 71, 7
Reference numeral 2 denotes the piezoelectric ceramic substrate 10 from the end surface 16 on the primary side.
Piezoelectric ceramic substrate 1 at a distance of / 6
It is provided at a central portion in the width direction perpendicular to the longitudinal direction of 0. The connecting portions 73 and 74 are the piezoelectric ceramic substrate 10.
Is provided at a distance of ⅙ from the secondary end surface 17 of the.

In the present embodiment, the connecting portion 71 between the primary electrode 61 and the lead frame 81, and the primary electrode 6
2 is provided at the vibration node X, and the connecting portion 7 between the lead electrode 82 and the lead frame 82 is provided at the connecting portion 7 between the secondary electrode 35 and the lead frame 83.
3, and the connecting portion 74 between the secondary electrode 36 and the lead frame 84 is provided at the vibration node Z. Moreover, since the lead frames 81 to 84 are thin and rich in spring property, the piezoelectric transformer 100 is electrically connected. Inhibition of vibration of the piezoelectric transformer 100 caused by making a connection or supporting the piezoelectric transformer 100 can be made very small.

(Fourth Embodiment) FIG. 6 is a perspective view of a piezoelectric transformer according to a fourth embodiment. In the third embodiment, the secondary electrodes 35 and 36 are arranged so as to face each other in the width direction of the piezoelectric ceramic substrate 10 on the width direction end face 18 side and the width direction end face 19 side of the upper surface 12 of the piezoelectric ceramic substrate 10. In addition, from the secondary side end surface 17 to a position separated from the secondary side end surface 17 by a distance of a little less than 1/3 of the length of the piezoelectric ceramic substrate 10 in the longitudinal direction, respectively, but in the present embodiment, Secondary electrodes 37, 3
8 on the widthwise end faces 18 and 19 of the piezoelectric ceramic substrate 10, from the secondary end face 17 to a position separated from the secondary end face 17 by a distance of a little less than 1/3 of the longitudinal length of the piezoelectric ceramic substrate 10. Although the respective points are different from those of the third embodiment, the other points are the same as those of the third embodiment.
The piezoelectric ceramic substrate 10 between the secondary electrode 38 and the secondary electrode 38 is polarized in the width direction of the piezoelectric ceramic substrate 10, and the connection points 75 and 76 between the secondary electrodes 37 and 38 and the electrode terminals are respectively formed. The same applies to a point Z provided for vibration in the longitudinal direction 10 of the piezoelectric transformer 100 and a supporting point on the secondary side of the piezoelectric transformer 100 provided for node Z for vibration in the longitudinal direction of the piezoelectric ceramic substrate 10.

(Fifth Embodiment) FIG. 7 is a diagram of a piezoelectric transformer according to a fifth embodiment, FIG. 7A is a perspective view, and FIG. 7B is a sectional view.

In the third embodiment, the secondary electrode 3
5, 36 from the secondary side end face 17 to the widthwise end face 18 side and the widthwise end face 19 side of the upper surface 12 of the piezoelectric ceramic substrate 10 so as to face each other in the width direction of the piezoelectric ceramic substrate 10. The secondary electrode 41 is provided from the end surface 17 to a position separated from the end surface 17 by a distance of a little less than 1/3 of the length of the piezoelectric ceramic substrate 10 in the longitudinal direction.
On the widthwise end face 18 side of the upper surface 12 of 0 from the secondary side end face 17 to a position separated from the secondary side end face 17 by a distance of a little less than 1/3 of the length of the piezoelectric ceramic substrate 10 in the longitudinal direction,
The secondary electrode 42 is attached to the lower surface 14 of the piezoelectric ceramic substrate 10.
On the width direction end face 19 side of the piezoelectric ceramic substrate 10 from the secondary side end face 17 so as to face the secondary electrode 41 in the width direction of the piezoelectric ceramic substrate 10. The piezoelectric ceramic substrate 10 between the secondary electrode 41 and the secondary electrode 42 is the same as the third embodiment except that it is provided up to a position separated by a distance of a little less than 1/3. A point that is polarized in the width direction of the piezoelectric ceramic substrate 10 and connection points 77 and 78 between the secondary electrodes 41 and 42 and the electrode terminals are provided in the longitudinal vibration node Z of the piezoelectric ceramic substrate 10, respectively. The same applies to the support point on the secondary side of 100 and the point provided at the node Z of vibration in the longitudinal direction of the piezoelectric ceramic substrate 10.

In the present embodiment, since the secondary electrode 41 is provided on the upper surface 12 of the piezoelectric ceramic substrate, the secondary electrode 41 can be formed in the same film forming process as the primary electrode 61.
Since the secondary electrode 42 is provided on the lower surface 14 of the piezoelectric ceramic substrate, the secondary electrode 4 can be formed in the same film forming process as the primary electrode 62.
2 can be formed. Further, the connection with the lead or the lead frame is made only on the upper surface 12 and the lower surface 14, so that the shape of the lead or the lead frame can be simplified.

(Sixth Embodiment) FIG. 8 is a diagram for explaining a piezoelectric transformer according to an eighth embodiment of the present invention. FIG. 8A is a perspective view, FIG. 8B is a sectional view, and FIG. 8C. Is a diagram showing a stress distribution, and FIG. 8D is a diagram showing an amplitude distribution.

As shown in FIGS. 8A and 8B, a primary electrode 111 is provided on the left side 3/4 region of the upper surface 12 of the rectangular parallelepiped piezoelectric ceramic substrate 10, and the piezoelectric ceramic substrate 10 faces the primary electrode 111. The primary electrode 1 is also on the lower surface 14.
12 is provided, and the piezoelectric ceramics substrate 10 between the primary electrode 111 and the primary electrode 112 (primary side region f) is polarized in the thickness direction between the upper surface 12 and the lower surface 14.
However, the piezoelectric ceramic substrate 10 between the primary-side end face 16 and a distance from the primary-side end face 16 at a distance of ½ of the longitudinal length of the piezoelectric ceramic substrate 10 (region h) is polarized downward, and Between the distance from the end face 16 to 1/2 the length of the piezoelectric ceramic substrate 10 in the longitudinal direction and from the distance from the primary end face 16 to the distance of 3/4 of the longitudinal length of the piezoelectric ceramic substrate 10 (region The piezoelectric ceramic substrate 10 of i) is polarized upward, and the polarization of the piezoelectric ceramic substrate 10 in the region h and the polarization of the piezoelectric ceramic substrate 10 in the region i are opposite to each other.

Primary end face 1 of piezoelectric ceramic substrate 10
6 to 3 of the length of the piezoelectric ceramic substrate 10 in the longitudinal direction.
Secondary electrodes 43 and 44 are provided on the width direction end surfaces 18 and 19 of the piezoelectric ceramic substrate 10 between the distance / 4 and the secondary side end surface 17 (secondary side region g). It is provided from the side end face 17 to a position separated from the secondary side end face 17 by a distance of a little less than ¼ of the length of the piezoelectric ceramic substrate 10 in the longitudinal direction. The secondary electrode 43 is provided with a predetermined distance from the primary electrodes 111 and 112, and the secondary electrode 44 is provided with a predetermined distance from the primary electrodes 111 and 112. The piezoelectric ceramic substrate 10 between the secondary electrode 43 and the secondary electrode 44 is the piezoelectric ceramic substrate 10.
Is polarized in the width direction.

One end of the power source 200 is connected to the primary electrode 111 via the connecting portion 121, and the other end of the power source 200 is connected to the primary electrode 112 via the connecting portion 122.

The secondary electrode 43 is connected to one end of the CFL 300 as a load via the connecting portion 79, and the other end of the CFL 300 is connected to the secondary electrode 44 via the connecting portion 80.

When a voltage is applied from the power source 200 between the primary electrodes 111 and 122, an electric field is applied in the thickness direction in the left 3/4 region (primary side region f), and the electric field is displaced in the direction perpendicular to the polarization direction. The longitudinal vibration in the longitudinal direction is excited by the piezoelectric transverse effect, and the entire piezoelectric transformer 100 vibrates. In the piezoelectric transformer of the present embodiment, the primary side end surface 16 and the secondary side end surface 17
Driving is performed in a resonance mode in which a stress distribution of one wavelength exists between and. From the power supply 200, a voltage having a frequency equal to the resonance frequency of the one wavelength mode is applied. In the present embodiment, since both the primary side end surface 16 and the secondary side end surface 17 of the piezoelectric ceramic substrate 10 are open, the stress becomes zero and the amplitude becomes maximum at both ends of the piezoelectric ceramic substrate 10 in the longitudinal direction. Become. Further, in the present embodiment, since the resonance is performed in the one-wavelength mode, the stress distribution and the amplitude distribution are as shown in FIGS. 8C and 8D, respectively.

When driven in such a one-wavelength mode, the node of vibration is caused by the end face 16 on the primary side of the piezoelectric ceramic substrate 10.
From the primary side end surface 16 of the piezoelectric ceramic substrate 10 (node V) (node U) and at a distance of 3/4 (node V). In the present embodiment,
The connecting portions 121 and 122 are provided at the vibration node U.

In the present embodiment, the primary electrode 11
1, 112 from the primary side end surface 16 to the primary side end surface 1
6 to 3 of the length of the piezoelectric ceramic substrate 10 in the longitudinal direction.
It extends to the position of / 4 distance. Therefore, the electrode area on the primary side is increased, and the piezoelectric transformer 10 is correspondingly increased.
The input impedance of 0 is small. As a result, electric energy is easily supplied to the piezoelectric transformer 100 from the power supply 200.

The stress in the region h is in the direction of the upper surface 12 of the piezoelectric ceramics substrate 10, whereas the stress in the region i is in the direction of the lower surface of the piezoelectric ceramics substrate 10 and in the opposite direction to the stress in the region h. Is. The polarization direction of the region h is
Although the polarization direction of the region i is opposite, the direction of application of the electric field is the same. Therefore, from the power source 200 to the primary electrode 11
When a voltage is applied between 1 and 122, the piezoelectric ceramic substrate 10 in the region i vibrates so as to further increase the resonance excited by the voltage applied from the power source 200 to the region h. As a result, the power supply 200 on the primary side
The electric energy supplied from can be more efficiently converted into mechanical elastic energy.

As described above, in the present embodiment, in the primary side region f, the primary electrodes 111 and 112 are extended to the region i where the stress in the direction opposite to the stress in the region h is generated, and the polarization of the region h is performed. By making the direction different from the polarization direction of the region i and making the direction of applying the electric field the same, the input impedance of the piezoelectric transformer 100 is reduced, and electric energy is easily supplied from the power source 200 to the piezoelectric transformer 100. Since the input electric energy can be more efficiently converted into mechanical elastic energy in the primary side region f, the effective step-up ratio of the piezoelectric transformer 100 can be increased.

Further, in the present embodiment, a secondary electrode 43 is provided on the end surface 18 in the width direction of the piezoelectric ceramic substrate 10 in the secondary region g, and the secondary electrode 43 is provided so as to face the secondary electrode 43. The secondary electrode 44 is also provided on the end face 19 in the width direction, and the piezoelectric ceramic substrate 10 between the secondary electrode 43 and the secondary electrode 44 is the piezoelectric ceramic substrate 10.
Is polarized in the width direction. Therefore, the piezoelectric ceramic substrate 1 between the secondary electrode 43 and the secondary electrode 44 is
0 is coupled with resonance in the longitudinal direction of the piezoelectric ceramics substrate 10 excited by the piezoelectric ceramics substrate 10 between the primary electrodes 111 and 112 with Poisson's ratio, vibrates in the widthwise direction of the piezoelectric ceramics substrate 10, and mechanically in the widthwise direction. Distortion occurs and a potential difference occurs in the polarization direction in the width direction, which can be taken out by the secondary electrodes 43 and 44.

As described above, the secondary electrode 4 is provided on the secondary side.
3 and the secondary electrode 44 are provided independently of the primary electrodes 111 and 112 in terms of direct current, it is possible to separate the primary side circuit and the secondary side circuit in terms of direct current. Insulating the primary side ground and the secondary side ground by forming independent ground electrodes on the secondary side and the primary side (for example, the primary electrode 112 and the secondary electrode 43 are independent ground electrodes). It is also possible to float the secondary side without grounding (for example, to float the secondary electrode 43 without grounding), and improve noise resistance.

In this embodiment also, since the vibration nodes X and Z are used as the support points of the piezoelectric transformer 100, the inhibition of the vibration of the piezoelectric transformer 100 caused by supporting the piezoelectric transformer 100 is made extremely small. be able to.

[0103]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a piezoelectric transformer 100 according to an embodiment of the present invention and a method for manufacturing the same will be described with reference to FIGS.

In this embodiment, as shown in FIGS. 3A and 3B, Pb (Ni _1/3 Nb _2/3 ) O ₃ -Pb (Zn _1/3
A rectangular parallelepiped having a length of 36 mm, a width of 7 mm, and a thickness of 1 mm was cut out from the Nb _2/3 ) O ₃ -PbTiO ₃ -PbZrO ₃ -based piezoelectric ceramic fired body to obtain a piezoelectric ceramic substrate 10. . Next, as shown in FIG. 4, silver electrodes were applied to the upper surface 12 and the lower surface 14 of the piezoelectric ceramic substrate 10 by screen printing. After that, baking is performed in air at 600 ° C. to form the primary electrode 63 on the upper surface 12 of the region c of the piezoelectric ceramic substrate 10 and the lower surface 14 of the region c of the piezoelectric ceramic substrate 10.
Is a primary electrode 64 on the upper surface 12 of the region d of the piezoelectric ceramic substrate 10, a primary electrode 66 on the lower surface 14 of the region d of the piezoelectric ceramic substrate 10, and a piezoelectric ceramic substrate on the secondary side region b. Secondary electrodes 35 and 36 were formed on the upper surface 12 of the electrode 10. The secondary electrode 35,
It is provided in the longitudinal direction of the piezoelectric ceramic substrate 10 over a length of 10 mm from the secondary side end face 17, and the width direction end face 18 is provided.
From 1 mm to the piezoelectric ceramic substrate 1
It was provided inside 0 in the width direction. The secondary electrode 36 is provided in the longitudinal direction of the piezoelectric ceramic substrate 10 over the length of 10 mm from the secondary side end face 17, and 1 m from the width direction end face 19
It was provided inside the width direction of the piezoelectric ceramic substrate 10 over a length of m. The distance between the secondary electrode 35 and the secondary electrode 36 was 5 mm, and the length of the secondary electrode 35 and the secondary electrode 36 facing each other was 10 mm.

Thereafter, the primary electrode 63 is connected to the positive electrode of a high voltage DC power supply (not shown) for polarization, the primary electrode 64 is connected to the negative electrode of this high voltage DC power supply (not shown) for polarization, and The primary electrode 65 is connected to the negative electrode of another high voltage DC power supply for polarization (not shown), and the primary electrode 66 is connected to the positive electrode of this other high voltage DC power supply for polarization (not shown) at 100 ° C.
By applying 2 kV from each of these two high-voltage DC power supplies in the silicone oil of No. 3, the regions c and d were polarized in the thickness direction.

After that, the secondary electrode 35 is connected to the negative electrode of a high-voltage DC power supply (not shown) for polarization, the secondary electrode 36 is connected to the positive electrode of this high-voltage DC power supply, and the product is placed in silicone oil at 100 ° C. By applying 10 kV, polarization processing in the width direction of the secondary region b was performed.

Thereafter, the conductive paste 67 connects the primary electrodes 63 and 65 to form the primary electrode 61 shown in FIG. 1, and the conductive paste 68 connects the primary electrodes 64 and 66 to the primary electrode 61 shown in FIG. A piezoelectric transformer 100 was used as the primary electrode 62.

Next, the piezoelectric transformer 100 was suspended by a lead wire, and the impedance characteristics on the primary side and the secondary side were measured. FIG. 9 shows impedance characteristics on the primary side, and FIG. 11 shows impedance characteristics on the secondary side.

Next, as shown in FIG. 5, the primary electrode 61 is connected and fixed to the vicinity of one end of the lead frame 71 by welding at the connecting portion 71, and the primary electrode 62 is welded at one end of the lead frame 82 at the connecting portion 72. In the vicinity of the portion 72, the connection and the fixation were made by welding. The secondary electrode 35 was connected and fixed to the vicinity of one end of the lead frame 83 at the connection portion 73, and the secondary electrode 36 was connected and fixed to the vicinity of one end of the lead frame 84 at the connection portion 74 by welding.

In this state, the impedance characteristics of the primary side and the secondary side were measured. FIG. 10 shows the impedance characteristic on the primary side, and FIG. 12 shows the impedance characteristic on the secondary side. Compared with the impedance characteristics when the piezoelectric transformer 100 is suspended by the lead wires shown in FIGS. 9 and 11, although the resonance impedance is slightly increased,
It was a level that practically had no effect. In addition, spurious was not observed, and excellent characteristics were shown.

After that, as shown in FIG. 3 and FIG.
00 to the primary electrode 61 via the lead frame 81.
And the other end of the power source 200 was connected to the primary electrode 62 via the lead frame 82. The secondary electrode 35 is connected to one end of the CFL 300 via the lead frame 83, and the CF
The other end of L300 was connected to the secondary electrode 36 via the lead frame 84. The CFL45 has a length of 225 m, which is used for A4 notebook personal computers.
m having a diameter of 2.6 mm was used.

A voltage of 130 kHz was applied from the power source 200. In this embodiment, the input voltage of 30 V _rms is 3
A brightness of CFL300 of 10,000 cd / m ² was obtained. The lighting of the CFL 300 could be started by applying an input voltage of about 18 V _rms .

[0113]

According to the piezoelectric transformer of the present invention, a large boosting ratio can be obtained. The piezoelectric transformer of the present invention is C
It can be suitably used as a FL lighting step-up transformer, in which case the input voltage can be reduced.

Further, the lead wire or lead frame from the secondary electrode can be drawn out from the nodes of the vibration of the first and second secondary electrodes in the first direction, respectively, and as a result, The secondary side can be easily electrically connected and mechanically supported without disturbing the vibration in the first direction, so that the output of the piezoelectric transformer is stable and the casing is easy.

Furthermore, the circuit on the primary side and the circuit on the secondary side can be separated in terms of direct current, and the noise resistance is also improved.

[Brief description of drawings]

1A and 1B are views for explaining a piezoelectric transformer according to a first embodiment of the present invention, FIG. 1A is a perspective view, FIG. 1B is a sectional view, FIG. 1C is a view showing stress distribution, and FIG. 1D is amplitude. It is a figure which shows distribution.

FIG. 2 is a perspective view for explaining a piezoelectric transformer according to a second embodiment of the present invention.

3A and 3B are diagrams for explaining a piezoelectric transformer according to a third embodiment of the present invention, FIG. 3A is a perspective view, FIG. 3B is a sectional view, FIG. 3C is a stress distribution diagram, and FIG. 3D is amplitude. It is a figure which shows distribution.

FIG. 4 is a perspective view for explaining a method of manufacturing a piezoelectric transformer according to a third embodiment of the present invention.

FIG. 5 is a perspective view for explaining a piezoelectric transformer mounting method according to a third embodiment of the present invention.

FIG. 6 is a perspective view illustrating a piezoelectric transformer according to a fourth embodiment of the present invention.

7A and 7B are views for explaining a piezoelectric transformer according to a fifth embodiment of the present invention, FIG. 7A is a perspective view, and FIG. 7B is a sectional view.

8A and 8B are views for explaining a piezoelectric transformer according to a sixth embodiment of the present invention, FIG. 8A is a perspective view, FIG. 8B is a sectional view, FIG. 8C is a view showing a stress distribution, and FIG. 8D is an amplitude. It is a figure which shows distribution.

FIG. 9 is a diagram showing impedance characteristics on the primary side of the piezoelectric transformer according to the embodiment of the present invention.

FIG. 10 is a diagram showing impedance characteristics on the primary side of the piezoelectric transformer according to the embodiment of the present invention in a mounted state.

FIG. 11 is a diagram showing impedance characteristics on the secondary side of the piezoelectric transformer according to the embodiment of the present invention.

FIG. 12 is a diagram showing impedance characteristics on the secondary side of the piezoelectric transformer in the mounted state, which is the piezoelectric transformer according to the embodiment of the present invention.

13A and 13B are diagrams for explaining a conventional piezoelectric transformer, FIG. 13A is a perspective view, FIG. 13B is a sectional view, FIG. 13C is a stress distribution diagram, and FIG. 13D is an amplitude distribution diagram.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Piezoelectric ceramics substrate 12 ... Upper surface 14 ... Lower surface 16 ... Primary end surface 17 ... Secondary end surface 18, 19 ... Width direction end surface 21, 22, 23, 24, 61, 62, 63, 64, 6
5, 66, 111, 112 ... Primary electrodes 31, 32, 33, 34, 35, 36, 37, 38, 4
1, 42, 43, 44 ... Secondary electrodes 51, 52, 53, 54, 55, 56, 57, 58, 7
1, 72, 73, 74, 75, 76, 77, 78, 7
9, 80, 121, 122 ... Connection part 67, 68 ... Conductive paste 81, 82, 83, 84 ... Lead frame 91, 92 ... Support part 100 ... Piezoelectric transformer 200 ... Power source 221, 222 ... Primary electrode 231, 232 ... Connection part 241 ... Secondary electrode 300 ... Cold cathode tube (CFL) a, f ... Primary side area b, g ... Secondary side area c, d, e, h, i, j ... Area S, T, U, V , X, Y, Z ... Vibration nodes

Claims (21)

[Claims] 1. A substantially rectangular parallelepiped piezoelectric substrate having a first main surface and a second main surface facing the first main surface, wherein one side of the first main surface extends. In a piezoelectric transformer that uses a longitudinal vibration resonance mode of the piezoelectric substrate in a first direction that is a direction in which the resonance mode is a resonance mode in which a stress distribution of at least one wavelength is present in the first direction, The piezoelectric substrate has a first region, a second region, and a third region in the first direction, and the first region, the second region, and the third region are different from each other. And the first region has a half-wavelength length of the stress distribution at the time of resonance in the first direction and has one of positive or negative in the first direction at the time of resonance. A first predetermined region of the piezoelectric substrate where stress is generated, A first primary electrode and a second primary electrode are provided to face each other on the first main surface and the second main surface of the first region, respectively, and the first primary electrode of the first region is provided. And the second primary electrode are polarized in the thickness direction between the first main surface and the second main surface, and the second region has the stress distribution at the time of resonance in the first direction. Is a second predetermined region of the piezoelectric substrate having a length equal to or less than a half wavelength and in which one of positive and negative stress is generated in the first direction at the time of resonance, A third primary electrode and a fourth primary electrode are provided to face each other on the first main surface and the second main surface of the second region, and are excited by the first and second primary electrodes. The second region vibrates to further increase the resonance As described above, the space between the third primary electrode and the fourth primary electrode in the second region is polarized in a predetermined direction in accordance with the direction of the stress generated in the second region during the resonance, and A third primary electrode and the fourth primary electrode and the first
The first primary surface and the second primary electrode are electrically connected to each other in a predetermined connection state, and in the third region, other than the first main surface perpendicular to the one side of the first main surface. A first secondary electrode and a second secondary electrode that face each other in a second direction that is a direction in which the side of extends, and at least the first secondary electrode in the third region. Second
The third region between the second electrode and the second electrode is polarized in the second direction. 2. The direction of the stress generated in the second region at the time of resonance is opposite to the direction of the stress generated in the first region at the time of resonance, and the third primary electrode in the second region is formed. A polarization direction between the fourth primary electrodes is opposite to a polarization direction between the first primary electrode and the second primary electrode in the first region, the third primary electrode and the first primary electrode. 2. The piezoelectric transformer according to claim 1, wherein the primary electrode is electrically connected, and the fourth primary electrode and the second primary electrode are electrically connected. 3. The direction of stress generated in the second region at the time of resonance is opposite to the direction of stress generated in the first region at the time of resonance, and the third primary electrode in the second region is formed. The polarization direction between the fourth primary electrodes is the same as the polarization direction between the first primary electrode and the second primary electrode in the first region, the third primary electrode and the second primary electrode. 2. The piezoelectric transformer according to claim 1, wherein the first primary electrode is electrically connected, and the fourth primary electrode and the first primary electrode are electrically connected. 4. The direction of stress generated in the second region at the time of resonance is the same as the direction of stress generated in the first region at the time of resonance, and the third primary electrode in the second region is formed. The polarization direction between the fourth primary electrodes is the same as the polarization direction between the first primary electrode and the second primary electrode in the first region, and the third primary electrode and the first primary electrode. 2. The piezoelectric transformer according to claim 1, wherein the primary electrode is electrically connected, and the fourth primary electrode and the second primary electrode are electrically connected. 5. The piezoelectric substrate further has a fourth region which is a region different from the first to third regions, and the fourth region is at the time of the resonance in the first direction. A predetermined fourth region of the piezoelectric substrate, which has a length equal to or less than a half wavelength of the stress distribution and is generated only in the same direction as the stress generated in the first region at the resonance, A fifth primary electrode and a sixth primary electrode are provided to face each other on the first main surface and the second main surface of the fourth region of the piezoelectric substrate, respectively, and the fourth region The polarization direction between the fifth primary electrode and the sixth primary electrode is the same as the polarization direction between the first primary electrode and the second primary electrode in the first region, 5 primary electrodes and the first primary electrodes are electrically connected, and the sixth primary electrodes are electrically connected. The piezoelectric transformer according to claim 2 or 3, wherein the secondary electrode and the second primary electrode are electrically connected. 6. The piezoelectric transformer according to claim 1, wherein the second region is located between the first region and the third region. 7. The piezoelectric transformer according to claim 5, wherein the second region and the fourth region are located between the first region and the third region. 8. A first main surface, a second main surface facing the first main surface, and a direction perpendicular to a first direction in which one side of the first main surface extends. A piezoelectric transformer comprising a substantially rectangular parallelepiped piezoelectric substrate having a first end face and a second end face, and utilizing a longitudinal vibration resonance mode of the piezoelectric substrate in the first direction, comprising: A primary electrode is on the first main surface and the second main surface of the piezoelectric substrate and is about ½ of a distance from the first end surface to the first end surface and the second end surface. The first region is provided in a predetermined region of the piezoelectric substrate between the first and second primary electrodes and the second end face, the first region extending to a position of a length distance in the first direction. On the main surface and the second main surface of the first and second primary electrodes, separated from each other by the third and fourth primary electrodes. Electrodes are respectively provided, the piezoelectric substrate between the first primary electrode and the second primary electrode is polarized in a thickness direction between the first main surface and the second main surface, and the third The piezoelectric substrate between the primary electrode and the fourth primary electrode is polarized in the thickness direction in the same direction as the polarization direction of the piezoelectric substrate between the first primary electrode and the second primary electrode; Primary electrode and the first primary electrode are electrically connected, the third primary electrode and the second primary electrode are electrically connected, and the third and fourth primary electrodes and the second primary electrode are electrically connected. Opposite to each other in a second region, which is a direction in which another side of the first main surface perpendicular to the one side of the first main surface extends in a predetermined region between the end surface of the piezoelectric substrate and the end surface of the piezoelectric substrate. A first secondary electrode and a second secondary electrode are provided. A piezoelectric transformer in which the piezoelectric substrate between the secondary electrodes second secondary electrode is characterized in that it is polarized in the second direction. 9. A first main surface, a second main surface facing the first main surface, and a first direction which is a direction in which one side of the first main surface extends and is orthogonal to the first direction. A piezoelectric transformer comprising a substantially rectangular parallelepiped piezoelectric substrate having a first end face and a second end face, and utilizing a longitudinal vibration resonance mode of the piezoelectric substrate in the first direction, comprising: A primary electrode is provided on the first main surface and the second main surface of the piezoelectric substrate and is about ⅓ of a distance from the first end surface to the first end surface and the second end surface. The third and fourth primary electrodes are provided so as to respectively extend in the first direction to a position of a distance of a length, and third and fourth primary electrodes are provided on the first main surface and the second main surface of the piezoelectric substrate, Approximately 1/3 of the distance between the first end surface and the second end surface from the first end surface
From the position of the distance of the length from the first end face to the first
The first and second primary electrodes and the secondary electrode, spaced apart by a distance of about 2/3 of the distance between the end surface of the first end and the second end surface of the first end. The piezoelectric substrate between the first primary electrode and the second primary electrode is polarized in the thickness direction between the first main surface and the second main surface, The piezoelectric substrate between the third primary electrode and the fourth primary electrode is polarized in the thickness direction in the same direction as the polarization direction of the piezoelectric substrate between the first primary electrode and the second primary electrode. The fourth primary electrode and the first primary electrode are electrically connected, the third primary electrode and the second primary electrode are electrically connected, the third and fourth primary electrodes In a predetermined region of the piezoelectric substrate between the first end surface and the second end surface. A first secondary electrode and a second secondary electrode facing each other in a second direction which is a direction in which the other side of the first main surface perpendicular to the one side of the main surface extends. A piezoelectric transformer, wherein the piezoelectric substrate between the first secondary electrode and the second secondary electrode is polarized in the second direction. 10. A predetermined area of the piezoelectric substrate between the third and fourth primary electrodes and the first and second secondary electrodes, on the first main surface and the second main surface. And a fifth and a sixth primary electrode are respectively provided apart from the third and fourth primary electrodes and the first and second secondary electrodes, and the fifth primary electrode and the fifth primary electrode are separated from each other. 6, the piezoelectric substrate between the primary electrodes is polarized in the thickness direction in the same direction as the polarization direction of the piezoelectric substrate between the first primary electrode and the second primary electrode, and the fifth primary electrode and the 10. The piezoelectric transformer according to claim 9, wherein the first primary electrode is electrically connected, and the sixth primary electrode and the second primary electrode are electrically connected. 11. A first main surface, a second main surface opposite to the first main surface, and a direction perpendicular to a first direction in which one side of the first main surface extends. A piezoelectric transformer comprising a substantially rectangular parallelepiped piezoelectric substrate having a first end face and a second end face, and utilizing a longitudinal vibration resonance mode of the piezoelectric substrate in the first direction, comprising: A primary electrode is on the first main surface and the second main surface of the piezoelectric substrate and is about ½ of a distance from the first end surface to the first end surface and the second end surface. The first region is provided in a predetermined region of the piezoelectric substrate between the first and second primary electrodes and the second end face, the first region extending to a position of a length distance in the first direction. On the main surface and the second main surface of the third and fourth main electrodes, spaced apart from the first and second primary electrodes. Secondary electrodes are respectively provided, the piezoelectric substrate between the first primary electrode and the second primary electrode is polarized in a thickness direction between the first main surface and the second main surface, and the third electrode is provided. The piezoelectric substrate between the first primary electrode and the fourth primary electrode is polarized in a direction opposite to the polarization direction of the piezoelectric substrate between the first primary electrode and the second primary electrode in the thickness direction, Three primary electrodes and the first primary electrode are electrically connected, the fourth primary electrode and the second primary electrode are electrically connected, and the third and fourth primary electrodes and the third primary electrode are electrically connected. In a predetermined region of the piezoelectric substrate between the two end faces, in a second direction which is a direction in which another side of the first main surface perpendicular to the one side of the first main surface extends. A first secondary electrode and a second secondary electrode facing each other are provided; A piezoelectric transformer in which the piezoelectric substrate between the secondary electrodes second secondary electrode is characterized in that it is polarized in the second direction. 12. A first main surface, a second main surface facing the first main surface, and a direction perpendicular to a first direction in which one side of the first main surface extends. A piezoelectric transformer comprising a substantially rectangular parallelepiped piezoelectric substrate having a first end face and a second end face, and utilizing a longitudinal vibration resonance mode of the piezoelectric substrate in the first direction, comprising: A primary electrode is provided on the first main surface and the second main surface of the piezoelectric substrate and is about ⅓ of a distance from the first end surface to the first end surface and the second end surface. The third and fourth primary electrodes are provided so as to respectively extend in the first direction to a position of a distance of a length, and third and fourth primary electrodes are provided on the first main surface and the second main surface of the piezoelectric substrate, Approximately 1/3 of the distance between the first end surface and the second end surface from the first end surface
From the position of the distance of the length from the first end face to the first
The first and second primary electrodes and the secondary electrode, spaced apart by a distance of about 2/3 of the distance between the end surface of the first end and the second end surface of the first end. The piezoelectric substrate between the first primary electrode and the second primary electrode is polarized in the thickness direction between the first main surface and the second main surface, The piezoelectric substrate between the third primary electrode and the fourth primary electrode is polarized in the thickness direction in a direction opposite to the polarization direction of the piezoelectric substrate between the first primary electrode and the second primary electrode. The third primary electrode and the first primary electrode are electrically connected, the fourth primary electrode and the second primary electrode are electrically connected, the third and fourth primary electrodes In a predetermined region of the piezoelectric substrate between the first end surface and the second end surface. A first secondary electrode and a second secondary electrode facing each other in a second direction which is a direction in which the other side of the first main surface perpendicular to the one side of the main surface extends. A piezoelectric transformer, wherein the piezoelectric substrate between the first secondary electrode and the second secondary electrode is polarized in the second direction. 13. On the first main surface and the second main surface of a predetermined area of the piezoelectric substrate between the third and fourth primary electrodes and the first and second secondary electrodes. And a fifth and a sixth primary electrode are respectively provided apart from the third and fourth primary electrodes and the first and second secondary electrodes, and the fifth primary electrode and the fifth primary electrode are separated from each other. 6, the piezoelectric substrate between the primary electrodes is polarized in the thickness direction in the same direction as the polarization direction of the piezoelectric substrate between the first primary electrode and the second primary electrode, and the fifth primary electrode and the 13. The piezoelectric transformer according to claim 12, wherein the first primary electrode is electrically connected, and the sixth primary electrode and the second primary electrode are electrically connected. 14. The first and second secondary electrodes are both provided on one of the first main surface and the second main surface of the piezoelectric substrate. The piezoelectric transformer according to any one of claims 1 to 13. 15. The first secondary electrode is provided on one main surface of the first main surface and the second main surface of the piezoelectric substrate, and the second secondary electrode is provided. 14. The piezoelectric transformer according to claim 1, wherein an electrode is provided on the other main surface of the first main surface and the second main surface of the piezoelectric substrate. . 16. The piezoelectric substrate has a third end face and a fourth end face orthogonal to the second direction, and the first secondary electrode is the third end face of the piezoelectric substrate and the third end face. The second secondary electrode is provided on one end face of the fourth end faces, and the second secondary electrode is provided on the other end face of the third end face and the fourth end face of the piezoelectric substrate. The piezoelectric transformer according to any one of claims 1 to 13, wherein 17. The piezoelectric element according to claim 1, wherein a support portion of the piezoelectric transformer is provided at a position of a node of the vibration in the resonance mode of the piezoelectric transformer in the first direction. Trance. 18. An electrical connection point to the primary electrode and an electrical connection point to the secondary electrode of the piezoelectric transformer are respectively located at the nodes of the vibration in the resonance mode of the piezoelectric transformer in the first direction. The piezoelectric transformer according to claim 1, wherein the piezoelectric transformer is provided. 19. The piezoelectric transformer according to claim 1, wherein the piezoelectric transformer is a cold-cathode tube lighting piezoelectric transformer. 20. An inverter incorporating the piezoelectric transformer according to claim 1. 21. A liquid crystal display incorporating the piezoelectric transformer according to claim 1.