JP2001053349A - Piezoelectric transformer, manufacturing method and mounting structure - Google Patents

Abstract

(57) [Problem] To provide a piezoelectric transformer having a structure suitable for mounting such as support and electrode extraction, a mounting structure thereof, and a manufacturing method. SOLUTION: An input unit 16 having input electrodes 14a and 14b.
Using a piezoelectric transformer 10 in which a vibrating section 12 including an output section 17 having output electrodes 15a and 15b and a fixed section 13 supporting the vibrating section are integrally formed, mounting is possible without using a special member. A suitable piezoelectric transformer was provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric transformer used in a power converter such as an inverter for backlight of a liquid crystal display or an AC-DC converter, and a method of manufacturing the same.

[0002]

2. Description of the Related Art A piezoelectric transformer converts input electric energy into mechanical energy by an inverse piezoelectric effect, and converts the mechanical energy into electric energy again by a piezoelectric effect, thereby increasing or decreasing a voltage. Equipment.

[0003] Compared to electromagnetic transformers, piezoelectric transformers can (1) be used at higher power densities and are suitable for miniaturization, (2) can be made non-combustible, and (3) reduce noise due to electromagnetic induction. (4) It has the advantage of high efficiency. On the other hand, in the electromagnetic transformer, the power density is improved by increasing the frequency, but the magnetic loss increases with the increase in the frequency, so that the efficiency is reduced.

At present, a piezoelectric transformer is often used as an inverter for emitting light from a cold cathode tube as a backlight of a liquid crystal display.
Use as a C-DC converter is also being studied.

[0005] As an example of such a piezoelectric transformer, a Rosen-type piezoelectric transformer, which is currently most commonly used, is shown in FIG. The principle and operation will be described with reference to this Rosen-type piezoelectric transformer.

In the piezoelectric transformer 90, a piezoelectric body 91
Is made of PZT (lead zirconate titanate) ceramic or the like and has a plate shape. The piezoelectric body 91 has a configuration roughly divided into about half as an input section 92 and an output section 93. The input portion 92 has input electrodes 94a and 94b formed on its main plane by, for example, silver printing, and is polarized in the thickness direction. The output portion 94 has an output electrode 95 formed on an end face thereof, and is polarized in the major axis direction.

The operation of the piezoelectric transformer 90 thus formed is as follows. That is, the input electrode 94
When an AC electric signal is applied between a and b, mechanical vibration occurs due to the inverse piezoelectric effect. Due to the mechanical vibration, a stress is generated in the output portion 94, and a high voltage is generated between the output electrode 95 and the input electrodes 94a and 94b by a piezoelectric effect caused by the stress, and is taken out from the output electrode 95 as an electric vibration.

At this time, the step-up / step-down ratio of the piezoelectric transformer 90 is determined by the capacitance ratio between the input unit 92 and the output unit 93. By setting the applied AC electric signal near the resonance frequency of the piezoelectric body 91 in the major axis direction, strong mechanical vibration can be obtained.

[0009]

As described above, the piezoelectric transformer 90 has a function as a transformer due to the propagation of vibration in the piezoelectric body 91. Therefore, in the piezoelectric transformer 90, the piezoelectric body
At one node point, the support of the piezoelectric transformer 90 main body and the extraction of the input electrode 94 and the output electrode 95 are performed. However, like the piezoelectric transformer 90,
In a conventional Rosen-type piezoelectric transformer, when resonance in the λ mode (length of the piezoelectric body in the major axis direction = 1 wavelength) is used, two nodes near the center of each of the input unit 92 and the output unit 93 are used. The fixing and the extraction of the electrodes are performed by supporting the points with conductive rubber or the like, but this requires labor and cost in mounting the piezoelectric transformer. In addition, it causes vibration inhibition, waveform distortion, excitation of unnecessary vibration, and the like, and the efficiency of the transformer is reduced.

A piezoelectric transformer for generating a high voltage is:
For safety, it is necessary to cover the piezoelectric transformer itself with a case, and mounting the piezoelectric transformer requires labor and cost as well as supporting.

The present invention is directed to the above problems and provides a piezoelectric transformer having a structure suitable for supporting and mounting, a method of manufacturing the same, and a mounting structure.

[0012]

Means for Solving the Problems In order to solve the above-mentioned problems, a first present invention (corresponding to the first aspect of the present invention).
Generates a standing wave by applying a voltage, including (1) an input portion having a piezoelectric material as a main material having an input electrode and (2) an output portion having a piezoelectric material as a main material having an output electrode. Comprising a vibrating portion that vibrates, and a fixed portion that supports the vibrating portion,
The piezoelectric transformer is characterized in that at least a portion of the fixed portion that comes into contact with the vibration portion is formed integrally with the vibration portion.

[0013] Thus, the support from the outside becomes easy, and a piezoelectric transformer having a structure suitable for mounting can be provided.

According to a second aspect of the present invention (corresponding to the second aspect of the present invention), a portion where the vibrating portion and the fixed portion abut on each other includes at least a predetermined point including a node point of the standing wave. The piezoelectric transformer according to claim 1, wherein the piezoelectric transformer is a region.

[0015] Thereby, the attenuation of the vibration by the support can be reduced.

According to a third aspect of the present invention (corresponding to the third aspect of the present invention), a wiring can be drawn out from the input electrode or the output electrode by utilizing a part of the fixing portion. The piezoelectric transformer according to claim 1 or 2, wherein:

Thus, input and output can be obtained from the supporting portion, and a piezoelectric transformer suitable for mounting can be obtained.

According to a fourth aspect of the present invention (corresponding to the fourth aspect of the present invention), the piezoelectric material is a piezoelectric ceramic. Transformer.

As a result, an inexpensive piezoelectric transformer having a large piezoelectric constant can be provided.

According to a fifth aspect of the present invention (corresponding to the fifth aspect of the present invention), the piezoelectric input section and / or the piezoelectric output section have a laminated structure. A piezoelectric transformer according to any one of the fourth to fourth aspects of the present invention.

This makes it easy to adjust the capacitance of the piezoelectric input section or the piezoelectric output section and the step-up / step-down ratio of the piezoelectric transformer.

According to a sixth aspect of the present invention (corresponding to the sixth aspect of the present invention), the vibration mode of the vibrating portion is a longitudinal extension vibration. It is.

Thus, by utilizing the stretching vibration mode,
The present invention can be applied to a Rosen-type piezoelectric transformer having a general structure at present.

According to a seventh aspect of the present invention (corresponding to the seventh aspect of the present invention), the vibration mode of the vibrating portion is a spread vibration. 3 is a piezoelectric transformer according to the invention.

Thus, a vibration mode having a high coupling coefficient can be used.

According to an eighth aspect of the present invention (corresponding to the eighth aspect of the present invention), there is provided a method for manufacturing a piezoelectric transformer according to any one of the first to seventh aspects, wherein A sintering step of performing, after the sintering step, a polarization step of performing polarization of the piezoelectric material, and after the polarization step, forming the abutting portion of the fixed portion and the vibrating portion by using the piezoelectric element. And a gap forming step of forming a gap in a part of the material.

As a result, the piezoelectric transformer of the present invention can be manufactured even with a piezoelectric material having good piezoelectric characteristics but a high sintering temperature and a green sheet laminating method cannot be used.

According to a ninth aspect of the present invention (corresponding to the ninth aspect of the present invention), the gap forming step is any one of cutting, ultrasonic processing, and sand blasting. 3 is a method for manufacturing the piezoelectric transformer of the present invention.

Thus, the gap can be easily formed after the polarization of the piezoelectric body with little processing damage to the piezoelectric body.

A tenth aspect of the present invention (corresponding to the tenth aspect of the present invention) is the method of manufacturing a piezoelectric transformer according to any one of the first to seventh aspects, wherein a piezoelectric material is laminated. A laminating step, after the laminating step, a gap forming step of forming a gap in a part of the piezoelectric material to form the contact portion and the vibrating section of the fixed portion, and after the gap formation, A method for manufacturing a piezoelectric transformer, comprising: a sintering step of sintering a piezoelectric material; and a polarization step of polarizing the piezoelectric material after the sintering step.

Thus, the piezoelectric input section or the piezoelectric output section can be laminated on the green sheet, so that the capacitance and the step-up / step-down ratio of the piezoelectric transformer can be easily adjusted.
Further, since the gap can be formed at the stage of the soft green sheet, the processing becomes easy.

An eleventh aspect of the present invention (corresponding to the eleventh aspect of the present invention) is characterized in that the gap forming step is either punching or laser processing. This is a method for manufacturing a piezoelectric transformer.

Thus, a soft green sheet can be processed with high accuracy.

According to a twelfth aspect of the present invention (corresponding to the twelfth aspect of the present invention), there is provided a mounting structure of a piezoelectric transformer on which the piezoelectric transformer of the first to seventh aspects of the present invention is mounted. Attached from both sides of the, and comprises an exterior substrate sandwiching the fixing portion, the exterior substrate,
A piezoelectric transformer mounting structure including a space that does not hinder the vibration of the vibrating section.

Thus, the case of the piezoelectric transformer can be manufactured integrally, and the mounting of the piezoelectric transformer of the present invention is facilitated.

A thirteenth aspect of the present invention (corresponding to the thirteenth aspect of the present invention) is characterized in that the space is formed by a concave structure provided in the exterior substrate. A mounting structure for a piezoelectric transformer according to a twelfth aspect of the present invention.

Thus, the vibration of the vibrating section can be reliably protected.

According to a fourteenth aspect of the present invention (corresponding to the fourteenth aspect of the present invention), the space is provided by an adhesive or an adhesive sheet disposed between the piezoelectric body and the exterior substrate. A twelfth aspect of the present invention is the mounting structure of the piezoelectric transformer according to the present invention, which is formed by the torus structure.

Thus, the space formation and the bonding process can be performed at once.

A fifteenth aspect of the present invention (corresponding to the fifteenth aspect of the present invention) is a method for manufacturing a piezoelectric transformer mounting structure according to any one of the twelfth to fifteenth aspects,
A method for manufacturing a piezoelectric transformer, comprising a bonding step of bonding the piezoelectric transformer and the exterior substrate.

Thus, the case of the piezoelectric transformer can be manufactured integrally, and the piezoelectric transformer of the present invention suitable for mounting can be provided.

A sixteenth aspect of the present invention (corresponding to the sixteenth aspect of the present invention) is characterized in that the piezoelectric transformer mounting structure of the twelfth to fourteenth aspects of the present invention is mounted as a lifting element. Inverter.

Thus, the piezoelectric transformer of the present invention can be used as an inverter.

A seventeenth aspect of the present invention (corresponding to the seventeenth aspect of the present invention) is characterized in that the piezoelectric transformer mounting structure of the twelfth to fourteenth aspects is mounted as a lifting element. AC-DC converter.

Thus, the piezoelectric transformer of the present invention is
-Can be used as a DC converter.

[0046]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a perspective view of a piezoelectric transformer according to Embodiment 1 of the present invention. Hereinafter, the configuration of the piezoelectric transformer 10 of the present embodiment will be described together with its manufacturing process. First, in the piezoelectric transformer 10, the piezoelectric body 11
Is a PZT-based ceramic in which the vibrating portion 12 and the fixed portion 13 are integrally molded and sintered using a mold. In the piezoelectric body 11, the vibrating portion 12 has a long axis direction of 15 mm.
mm, the minor axis direction is 5 mm, and the thickness is 0.5 mm. The fixed part 13 is located at the center of the vibrating part 12 in the long side direction and has a size of 2 mm square.

Next, input electrodes 14a and 14b and output electrodes 15a and 15b are formed on both wafer-shaped main surfaces of the vibrating section 12 by silver baking.

Further, a high electric field is applied between the input electrodes 14a and 14b and between the input electrodes 14a and 14b and the output electrodes 15a and 15b to polarize the vibrating section 12 to form an input section 16 and an output section 17.

In the piezoelectric transformer 10 according to the present embodiment, manufactured as described above, the input section 16 and the output section 17 step up and down the voltage which is the function of the piezoelectric transformer. The input unit 16 corresponds to the surface on which the input electrodes 14a and 14b are formed, and is one half in the short axis direction of the vibrating unit 12, and the output unit 17 is on the side to which the surface on which the output electrodes 15a and 15b are formed. , Occupy the other half of the vibrating part 12 in the short axis direction. However, the polarization directions of the input unit 16 and the output unit 17 are indicated by arrows in FIG. Further, the fixing portion 13 has a role of holding the vibration of the vibrating portion 12 so as not to hinder as much as possible.

The piezoelectric transformer 10 according to the present embodiment having such a configuration is driven by elongational vibration in the long axis direction of λ / 2 mode in which the node point is located at the center of the vibrating part 12. The vibration part 12 and the fixed part 13 are configured to be connected at the center.

At this time, since the present embodiment has a configuration in which the vibrating portion 12 and the fixed portion 13 are integrally formed, it is necessary to use a component such as conductive rubber when mounting the piezoelectric transformer. Therefore, the mounting can be performed only by holding the fixed portion 13, and the input point stations 14 a and 14 b and the output electrodes 15 a and 15 b can be taken out simultaneously with the support of the vibrating portion 12.

The resonance frequency of the λ / 2 mode longitudinal vibration of the piezoelectric transformer according to the present embodiment is about 75.
kHz, and the efficiency when a load resistance of 20 kΩ is applied between the input electrode 14b and the output electrodes 15a and 15b is about 90%.
%, And the pressure increase ratio was 7 times.

Further, in the present embodiment, the vibration mode is the longitudinal elongation vibration, but the present invention is not limited to the vibration mode. (Embodiment 2) A perspective view and a top view of a piezoelectric transformer according to Embodiment 2 of the present invention are shown in FIGS. Hereinafter, the configuration of the piezoelectric transformer 20 according to the present embodiment will be described together with its manufacturing process. First, the piezoelectric body 21 is PZ
This is a T-based ceramic, and after sintering into a block shape, it is cut and polished to 15 mm in the long axis direction and 7 m in the short axis direction.
m, processed into a wafer shape with a thickness of 0.5 mm.

Next, input electrodes 24a and 24b and output electrodes 25a and 25b are formed on both main surfaces of the wafer of the piezoelectric body 21 by silver baking. These output electrodes 25a, b-input electrode 24
A high electric field is applied between the electrodes a and b and between the input electrodes 24a and 24b to polarize, thereby forming the input section 26 and the output section 27. However, the polarization directions of the input unit 26 and the output unit 27 are indicated by arrows in FIG.

Thereafter, as shown in FIG. 3, dicing is performed to place a width of 0.2 mm and a length of 6.5 mm on the piezoelectric body 21.
Are formed, and the piezoelectric body 21 is divided into the vibration part 22 and the fixed part 23.

In the piezoelectric transformer 20 according to the present embodiment manufactured as described above, the vibrating portion 22 is a portion including the input portion 26 and the output portion 27. The size is 15 mm in the major axis direction and 15 mm in the minor axis direction. The direction is 5 mm. Fixed part 23
Has a role of holding the vibration of the vibrating part 22 as little as possible, as in the first embodiment.

In the vibrating part 22, the input part 26 corresponds to the surface on which the input electrodes 24a and 24b are formed, and is one half in the short axis direction of the vibrating part 22, and the output part 27 is the output electrode 25a. vibrating part 2 on the side to which the surface on which b is formed belongs
2 occupy the other half in the minor axis direction. The input unit 26 and the output unit 27 having such a configuration perform the step-up and step-down of the voltage, which is the function of the piezoelectric transformer, as in the first embodiment.

The piezoelectric transformer 20 according to the present embodiment having the above-described configuration is driven by a longitudinal extension vibration in the λ / 2 mode in which the node point is located at the center of the vibrating portion 22. The vibrating part 22 and the fixed part 23 are connected at the center.

At this time, in the present embodiment, since the vibrating portion 22 and the fixed portion 23 are integrally formed,
When mounting the piezoelectric transformer, it is not necessary to use a component such as conductive rubber as in the first embodiment,
3 can be mounted, and the input electrodes 24a, b and the output electrodes 25a, b can be taken out simultaneously with the support of the vibration section 22.

The resonance frequency of the λ / 2 mode longitudinal vibration of the piezoelectric transformer according to the present embodiment is about 75.
and the efficiency when a load resistance of 20 kΩ is applied between the input electrode 24b and the output electrode 25a, b is about 90%.
%, And the pressure increase ratio was 7 times.

Further, in the present embodiment, the vibration mode is set to the longitudinal extension vibration, but the vibration mode is not limited. (Embodiment 3) A perspective view and a top view of a piezoelectric transformer according to Embodiment 3 of the present invention are shown in FIGS. FIG. 6 is a cross-sectional view taken along the line AA ′ in FIG. Hereinafter, the configuration of the piezoelectric transformer 30 according to the present embodiment will be described together with its manufacturing process. The piezoelectric body 31 is a PZT-based ceramic and is formed by processing a green sheet by a doctor blade method.

Next, the steps will be described. First, the input electrodes 34c and 34d are formed of a silver / palladium paste on a part of the green sheet using a screen printing method. Further, the green sheets are laminated and pressed to form the piezoelectric body 31.

Next, a part of the piezoelectric body 31 is punched out by punching to form a vibration space 38, and the piezoelectric body 31 is divided into a vibration part 32 and a fixed part 33. After the division, the entire piezoelectric body 31 is sintered.

After sintering, the input electrodes 34a and 34b and the output electrode 35 are manufactured by baking silver. Here, as shown in FIG. 6, the input electrode 34a is electrically connected to the input electrode 34c, and the input electrode 34b is electrically connected to the input electrode 34d on the side surface.

Finally, the output electrode 35-input electrode 34a,
A high electric field is applied between the electrodes b and between the input electrodes 34a and 34b to perform polarization, thereby forming the input portion 36 and the output portion 37.

The external size of the piezoelectric transformer 30 thus manufactured according to the present embodiment is 15
mm, the minor axis direction is 7 mm, and the thickness is 0.5 mm. The size of the vibrating part 32 is 15 mm in the major axis direction and 5 mm in the minor axis direction. The vibration space 38 is formed of a space having a width of 0.2 mm, and divides the function of the piezoelectric transformer 30 into each of the vibration part 32 and the fixed part 33. The vibrating section 32 has an input section 36 and an output section 37, and performs voltage boosting and stepping down, which are functions of the piezoelectric transformer. In the vibration part 32,
The input portion 36 corresponds to the surface on which the input electrodes 34a and 34b are formed, and is one half in the short axis direction of the vibrating portion 32. The output portion 37 is the vibration on the side to which the surface on which the output electrode 35 is formed belongs. The other half of the portion 32 in the short axis direction is occupied. However, the polarization directions of the input unit 36 and the output unit 37 are indicated by arrows in FIGS. 4 and 6, respectively. Further, the fixing portion 33 has a role of holding the vibration of the vibration portion 32 so as not to hinder the vibration as much as possible.

The piezoelectric transformer 30 according to the present embodiment having such a configuration is driven by the λ mode longitudinal vibration in which the node point is located at the center of each of the output unit 37 and the input unit 36. The vibrating part 32 and the fixed part 33 are connected at a node point.

At this time, since the present embodiment has a configuration in which the vibrating portion 32 and the fixed portion 33 are integrally formed, it is necessary to use a component such as conductive rubber when mounting the piezoelectric transformer. In other words, the piezoelectric transformer can be mounted only by holding the fixing portion 33.

The resonance frequency in the λ mode of the piezoelectric transformer according to the present embodiment is about 150 kHz. When a load resistance of 80 kΩ was provided between the input electrode 34b and the output electrode 35, the efficiency was about 93%, and the boost ratio was 15 times.

Further, in this embodiment, the vibration mode is set to the longitudinal extension vibration, but the present invention is not limited to the vibration mode. (Embodiment 4) An external view of a piezoelectric transformer according to Embodiment 4 of the present invention is shown in FIG. Hereinafter, the configuration of the piezoelectric transformer 40 according to the present embodiment will be described together with its manufacturing process. The piezoelectric body 41 is a PZT-based ceramic, and is formed by processing a green sheet by a doctor blade method.

Next, the steps will be described. First, the input electrodes 44b and c were formed on a part of the green sheet using a silver / palladium paste by using a screen printing method. The green sheets are laminated and pressed to form the piezoelectric body 41. Next, the piezoelectric body 41 is laser-processed to form a vibration space 48.
Is formed, the entire piezoelectric body 41 is sintered.

After sintering, the input electrode 44a and the output electrode 45 were manufactured by baking silver. At this time, the input electrode 44b,
c takes out an electrode from the side, and the input electrodes 44a and 44c are directly electrically connected to the outside.

Finally, the output electrode 45-input electrode 44c
A high electric field is applied between the electrodes and between the input electrodes 44a and c-41b to perform polarization, thereby forming an input portion 46 and an output portion 47. At this time, the polarization direction is indicated by an arrow in FIG.

The size of the piezoelectric transformer 40 thus manufactured according to the present embodiment has a circular shape of φ17 mm and a thickness of 0.5 mm. The size of the vibrating portion 42 is a ring shape having an outer diameter of 17 mm and an inner diameter of 3 mm. The vibration space 48 is formed with a space having a width of 0.2 mm, and divides the function of the piezoelectric transformer 40 into the vibration part 42 and the fixed part 43. The vibrating section 42 has an input section 46 and an output section 47, and performs a step-up and step-down of a voltage which is a function of the piezoelectric transformer. The input part 46 is about half in the thickness direction of the vibrating part 42 on which the input electrodes 44a, b, c are formed, and the output part 47 is about half on the side where the output electrode 45 is formed. The fixing part 43 has a role of holding the vibration of the vibration part 42 so as not to hinder the vibration as much as possible.

The piezoelectric transformer 40 according to the present embodiment having such a configuration is driven in the spread vibration mode in which the node point is located at the center.
In this embodiment, the vibrating part 42 and the fixing part 43 are integrally formed by sintering. As in the first to third embodiments, components such as conductive rubber do not need to be used, and the piezoelectric transformer can be mounted only by holding the fixing portion 43, so that support and fixing can be performed easily.

The resonance frequency of the first-order spread mode of the piezoelectric transformer according to the present embodiment is about 130 kHz. When a load resistance of 100Ω is provided between the input electrode 44c and the output electrode 45, the efficiency is about 92%, and the boost ratio is 2.3.
It was twice.

Further, in this embodiment, the vibration mode is set to the spread vibration, but the present invention is not limited to the vibration mode.

(Embodiment 5) A perspective view of a piezoelectric transformer according to Embodiment 5 of the present invention is shown in FIG. 8, and an electrode pattern is shown in FIG. Further, FIG. 10 shows a cross-sectional view along the line AA ′ in FIG. Hereinafter, the configuration of the piezoelectric transformer 50 according to the present embodiment will be described together with its manufacturing process. The piezoelectric body 51 is a PZT-based ceramic, and a green sheet is formed by a doctor blade method.

Next, the steps will be described. First, the input electrodes 54c, d, and e are formed of a silver / palladium paste on a part of the green sheet using a screen printing method. Further, the green sheets are laminated and pressed to form the piezoelectric body 51.

Next, a part of the piezoelectric body 51 is processed by laser processing to form a vibration space 58, and the piezoelectric body 51 is divided into a vibration part 52 and a fixed part 53. After the division, the entire piezoelectric body 51 is sintered.

After sintering, the input electrodes 54a and 54b and the output electrode 55 are formed by baking silver. Here, as shown in FIG. 10, the input electrode 54a is electrically connected to the input electrode 54c, and the input electrode 54b is electrically connected to the input electrodes 54d and e on the side surfaces.

Finally, the output electrode 55-input electrode 54b
The input portion 56 and the output portion 57 are formed by applying a high electric field between the input electrodes 54a and 54b and performing polarization. At this time, the polarization direction is indicated by an arrow in FIGS.

The size of the piezoelectric transformer 50 thus manufactured according to the present embodiment is a square having a side of 17 mm and a thickness of 0.5 mm. The size of the vibrating part 52 is 15 mm on one side. Vibration space 58
Is formed in a space having a width of 0.2 mm, and divides the function of the piezoelectric transformer 50 for each of the vibrating section 52 and the fixed section 53. The vibration unit 52 has an input unit 56 and an output unit 57,
It performs voltage boosting and stepping down, which are the functions of the piezoelectric transformer. The input section 56 is about half in the thickness direction of the vibrating section 52 on which the input electrodes 54a, b, c, d, and e are formed, and the output section 57 is about half on the side where the output electrode 55 is formed. In addition, the fixing portion 53 has a role of holding the vibration of the vibration portion 52 so as not to hinder as much as possible.

According to the piezoelectric transformer 50 according to the present embodiment having such a configuration, the vibrating portion 52 and the fixed portion 53
By sintering and forming a structure,
As in the first to fourth embodiments, it is not necessary to use a component such as a conductive rubber for support or the like, and it is possible to mount the piezoelectric transformer only by holding the fixing portion 53 and to draw out the input / output electrodes. As a result, support and fixing can be easily performed.

The resonance frequency of the piezoelectric transformer according to the present embodiment is about 150 kHz. Input electrode 54b-
The efficiency when a load resistance of 100Ω is provided between the output electrodes 55 is about 89%, and the boost ratio is 3.4 times. Does not limit the vibration mode to this. (Embodiment 6) An external view of a piezoelectric transformer according to Embodiment 6 of the present invention is shown in FIG. 11, and a top view is shown in FIG.
Hereinafter, the configuration of the piezoelectric transformer 60 according to the present embodiment will be described together with its manufacturing process.

First, the piezoelectric body 61 is a PZT-based ceramic, which is sintered into a block shape, and then cut and polished to form a wafer having a major axis direction of 17 mm, a minor axis direction of 7 mm, and a thickness of 0.5 mm. It was produced.

Next, the piezoelectric body 61 is sandblasted.
Was processed to form a vibration space 68, and the input electrodes 64a, b and the output electrodes 65a, b were produced by silver baking.

Finally, the output electrodes 65a, b and the input electrode 6
A high electric field is applied between the electrodes 4a and 4b and between the input electrodes 64a and 64b to perform polarization, thereby forming an input section 66 and an output section 67. However, the polarization direction is indicated by an arrow in FIG.

In the piezoelectric transformer 60 thus manufactured according to the present embodiment, the size of the vibrating portion 62 is 15 mm in the major axis direction and 5 mm in the minor axis direction. The vibration space 68 is formed by a space having a width of 0.2 mm.
Each is divided. The vibration section 62 includes an input section 64 and an output section 6.
5, which performs the step-up and step-down of the voltage which is the function of the piezoelectric transformer. The input section 66 is a central portion of the vibrating section 62 corresponding to the surface on which the input electrodes 64a and 64b are formed, and the output sections 67a and b are each a part on the side to which the surface on which the output electrodes 65a and 65b are formed. Become. The fixed part 63 is a vibrating part 6
It has the role of holding the vibration of 2 as little as possible.

The piezoelectric transformer according to the present embodiment having such a configuration is driven by the λ / 2 mode longitudinal vibration in the λ / 2 mode in which the node point is located at the center of the vibration section 62. 62 and the fixed portion 63 are connected at the center.

At this time, in the present embodiment, since the vibrating portion 12 and the fixed portion 13 are integrally formed, components such as conductive rubber are used when mounting the piezoelectric transformer. There is no need, and mounting is possible only by holding the fixing portion 63.

The resonance frequency of the piezoelectric transformer according to the present embodiment is about 75 kHz. When a load resistance of 50 kΩ was applied between the input electrode 64b and the output electrodes 65a and 65b, the efficiency was about 90%, and the boost ratio was 12 times.

Further, in the present embodiment, the vibration mode is set to the longitudinal elongation vibration, but the present invention is not limited to the vibration mode. (Embodiment 7) FIG. 13 is a structural diagram of a piezoelectric transformer and a mounting structure thereof according to Embodiment 7 of the present invention.
FIG. 14 is a cross-sectional view taken along the line AA ′ in FIG. Hereinafter, the configuration of the piezoelectric transformer having the mounting structure according to the present embodiment will be described together with its manufacturing process. The piezoelectric body 71 is P
It is a ZT-based ceramic and is formed by processing a green sheet by a doctor blade method.

Next, the steps will be described. First, the input electrodes 74a, b, c, d, e, and the output electrodes 75a, b, c,
d and e are formed with a silver / palladium paste. further,
The green sheets are laminated and pressed to form the piezoelectric body 71.

Next, a part of the piezoelectric body 71 is punched out by punching to form a vibration space 78, and the piezoelectric body 71 is divided into a vibration part 72 and a fixed part 73. After the division, the entire piezoelectric body 71 is sintered to obtain the piezoelectric wafer 70.

Here, the size of the piezoelectric wafer 70 is 17 mm in the major axis direction, 7 mm in the minor axis direction, and 0.5 mm in thickness. The size of the vibrating part 72 is 15 m in the long axis direction.
m, short axis direction is 5 mm, vibration space 78 is 0.2 mm in width
Space.

Subsequently, a 0.3 mm-thick alumina wafer having a concave structure with a depth of 0.1 mm is bonded as an exterior substrate 79a, b from above and below the piezoelectric wafer 70 using an adhesive.

Next, the input electrodes 7 are attached to the exterior substrates 79a and 79b.
4f, g, and the output electrode 75f are manufactured by baking silver.

Finally, the output electrode 75f-input electrode 74
A high electric field is applied between f and g and between the input electrodes 74f-74g to perform polarization, and an input section 76 and an output section 77 are formed in the piezoelectric wafer 70. However, the polarization direction is indicated by an arrow in FIG.

According to the piezoelectric transformer thus manufactured according to the present embodiment, the vibrating portion 72 and the fixed portion 73
Has a configuration in which the electrodes are integrally formed, so that it is not necessary to use a component such as a conductive rubber for support or the like, the electrode can be pulled out, and the support and fixation can be easily performed.
In addition, by attaching the exterior substrate, the piezoelectric transformer can be integrated with the case, and mounting is further facilitated.

Note that the piezoelectric transformer according to the present embodiment is driven by λ / 2 mode longitudinal vibration in which the node point is located at the center, and has a resonance frequency of about 75 kHz.
When a load resistance of 20 kΩ was applied between the input electrode 74g and the output electrode 75f, the efficiency was about 90%, and the boost ratio was 21 times.

Further, in the present embodiment, the vibration mode is set to the longitudinal extension vibration, but the present invention is not limited to the vibration mode. (Embodiment 8) FIG. 15 is a structural diagram of a piezoelectric transformer and a mounting structure thereof according to an embodiment 8 of the present invention.
FIG. 16 is a cross-sectional view taken along line AA ′ in FIG. The structure of the piezoelectric transformer according to the eighth embodiment is the same as that of the piezoelectric transformer according to the seventh embodiment, except for the external substrate which is the mounting structure. And the description is omitted.

The steps of manufacturing the piezoelectric transformer and the mounting structure thereof according to the eighth embodiment are as follows. That is, the piezoelectric feha 70 obtained in the same manner as in the seventh embodiment is used as an external substrate 89a, b using a plate-like alumina wafer having a thickness of 0.2 mm as an adhesive substrate 88a having a thickness of 25 μm from above and below the piezoelectric wafer 70. , B. At this time, the shape of the adhesive sheets 88a and 88b is such that the sheets are provided only at the end portions, and the center portion forms a cavity,
The piezoelectric wafer 70 will be arranged in this cavity.

Thereafter, the input electrodes 84f, g and the output electrode 8
5f was produced by baking silver. This output electrode 85f
Between the input electrodes 84f, g, and the input electrodes 84f-84.
The input portion 76 and the output portion 77 are formed in the piezoelectric wafer 70 by applying a high electric field between g and performing polarization. However, the polarization direction is indicated by an arrow in FIG. 16 which is a sectional view.

According to the piezoelectric transformer according to the present embodiment manufactured as described above, similar to the seventh embodiment, the vibrating portion 72 and the fixed portion 73 are integrally formed, so that It is not necessary to use a component such as conductive rubber for drawing out the electrodes.
It can be fixed easily. In addition, by using an adhesive sheet for the production of the mounting structure, the formation and bonding of the cavity can be performed simultaneously, and by bonding the exterior substrate,
The piezoelectric transformer can be integrated with the case, making mounting easy.

The piezoelectric transformer according to the present embodiment is driven by elongational vibration in the long axis direction of λ / 2 mode in which the node point is located at the center, and has a resonance frequency of about 75 kHz.
When a load resistance of 20 kΩ was applied between the input electrode 84g and the output electrode 85f, the efficiency was about 90%, and the boost ratio was 21 times.

Further, in the present embodiment, the vibration mode is set to the longitudinal extension vibration, but the present invention is not limited to the vibration mode.

In each of the embodiments of the present invention, a PZT-based ceramic is used as the piezoelectric body. However, a similar effect can be obtained with a piezoelectric substance, for example, a piezoelectric single crystal such as LiNO 3. .

In any of the embodiments of the present invention, the electrode pattern, the shape of the piezoelectric body, the shape of the vibration space,
It does not limit the polarization direction of the piezoelectric body.

Further, in any of the embodiments of the present invention, the piezoelectric transformer is used for boosting the voltage, but the same effect can be obtained even if the piezoelectric transformer is operated for the purpose of decreasing the voltage.

Further, the piezoelectric transformer or the mounting structure of the piezoelectric transformer of the present invention may be used as an elevating element for an inverter that emits light from a cold-cathode tube as a backlight of a liquid crystal display.

Further, the piezoelectric transformer or the mounting structure of the piezoelectric transformer of the present invention may be used for an AC-DC converter as an elevating element.

[0113]

As is apparent from the above description,
ADVANTAGE OF THE INVENTION According to this invention, external support becomes easy and the piezoelectric transformer of the structure suitable for mounting, its manufacturing method, and mounting structure can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of a piezoelectric transformer according to a first embodiment of the present invention.

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

FIG. 3 is a top view of a piezoelectric transformer according to a second embodiment of the present invention.

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

FIG. 5 is a top view of a piezoelectric transformer according to a third embodiment of the present invention.

FIG. 6 is a sectional view of a piezoelectric transformer according to a third embodiment of the present invention.

FIG. 7 is an external view of a piezoelectric transformer according to a fourth embodiment of the present invention.

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

FIG. 9 is a top view of a piezoelectric transformer according to a fifth embodiment of the present invention.

FIG. 10 is a sectional view of a piezoelectric transformer according to a fifth embodiment of the present invention.

FIG. 11 is a perspective view of a piezoelectric transformer according to a sixth embodiment of the present invention.

FIG. 12 is a top view of a piezoelectric transformer according to a sixth embodiment of the present invention.

FIG. 13 is a configuration diagram of a piezoelectric transformer and a mounting structure according to a seventh embodiment of the present invention.

FIG. 14 is a sectional view of a piezoelectric transformer and a mounting structure according to a seventh embodiment of the present invention.

FIG. 15 is a configuration diagram of a piezoelectric transformer and a mounting structure according to an eighth embodiment of the present invention.

FIG. 16 is a sectional view of a piezoelectric transformer and a mounting structure according to an eighth embodiment of the present invention.

FIG. 17 is an external view of a piezoelectric transformer according to a conventional technique.

[Explanation of symbols]

10, 20, 30, 40, 50, 60, 90 Piezoelectric transformers 11, 21, 31, 41, 51, 61, 71, 91 Piezoelectric bodies 12, 22, 32, 42, 52, 62, 72 Vibrating parts 13, 23 , 33, 43, 53, 63, 73 Fixing parts 14, 24, 34, 44, 54, 64, 74, 94 Input electrodes 15, 25, 35, 45, 55, 65, 75, 95 Output electrodes 16, 26, 36, 46, 56, 66, 76, 92 Input unit 17, 27, 37, 47, 57, 67, 77, 93 Output unit 38, 48, 58, 68, 78 Vibration space 70 Piezoelectric wafer 79, 89 Outer substrate 88 Resin sheet

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hiroshi Togawa 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Hiroyuki Hase 1006 Odaka Kadoma Kadoma City, Osaka Matsushita Electric Industrial Co. (72) Inventor Koji Kawakita 1006 Kadoma, Kazuma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. (72) The inventor Hiroshi Nakatsuka 1006 Odaka Kazuma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. 1006 Kadoma, Kazuma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (17)

[Claims] 1. An input part having an input electrode and made of a piezoelectric material as a main material, and (2) an output part having an output electrode and made of a piezoelectric material as a main material. A vibrating part that generates a wave and vibrates; and a fixing part that supports the vibrating part. At least a part of the fixing part that contacts the vibrating part is formed integrally with the vibrating part. Characteristic piezoelectric transformer. 2. The piezoelectric transformer according to claim 1, wherein a portion where the vibrating portion and the fixed portion contact each other is a predetermined region including at least a node point of the standing wave. 3. The piezoelectric transformer according to claim 1, wherein a wiring can be drawn out from the input electrode or the output electrode by using a part of the fixed portion. 4. The piezoelectric transformer according to claim 1, wherein the piezoelectric body is a piezoelectric ceramic. 5. The piezoelectric transformer according to claim 1, wherein the piezoelectric input section and / or the piezoelectric output section have a laminated structure. 6. The piezoelectric transformer according to claim 1, wherein the vibration mode of the vibrating portion is elongation vibration in a long axis direction. 7. The piezoelectric transformer according to claim 1, wherein the vibration mode of the vibrating section is a spread vibration. 8. The method for manufacturing a piezoelectric transformer according to claim 1, wherein a sintering step of sintering the piezoelectric material, and polarization of the piezoelectric material after the sintering step. And a gap forming step of forming a gap in a part of the piezoelectric material to form the abutting portion of the fixed portion and the vibrating portion after the polarization process. Manufacturing method of piezoelectric transformer. 9. The method according to claim 8, wherein the gap forming step is any one of cutting, ultrasonic processing, and sandblasting. 10. The method for manufacturing a piezoelectric transformer according to claim 1, wherein: a laminating step of laminating a piezoelectric material; and after the laminating step, the abutting portion of the fixed portion and the vibration. A gap forming step of forming a gap in a part of the piezoelectric material to form a portion; a sintering step of sintering the piezoelectric material after the gap is formed; and A method for manufacturing a piezoelectric transformer, comprising a polarization step of polarizing a material. 11. The method according to claim 10, wherein the gap forming step is punching or laser processing. 12. A mounting structure of a piezoelectric transformer on which the piezoelectric transformer according to claim 1 is mounted, wherein the piezoelectric transformer is attached from both sides of the piezoelectric transformer.
A mounting structure for a piezoelectric transformer, comprising: an exterior substrate that sandwiches the fixing portion, wherein the exterior substrate includes a space that does not hinder the vibration of the vibrating portion. 13. The piezoelectric transformer mounting structure according to claim 12, wherein the space is formed by a concave structure provided in the exterior substrate. 14. The space portion is formed by a torus structure provided by an adhesive or an adhesive sheet disposed between the piezoelectric body and the exterior substrate. The mounting structure of the piezoelectric transformer described in 1. 15. The method for manufacturing a mounting structure of a piezoelectric transformer according to claim 12, further comprising a bonding step of bonding the piezoelectric transformer and the exterior substrate. Production method. 16. An inverter, wherein the mounting structure of the piezoelectric transformer according to claim 12 is mounted as a lifting element. 17. An AC-DC converter, wherein the piezoelectric transformer mounting structure according to claim 12 is mounted as a lifting element.