JPH09246618A - Piezoelectric transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the suppression of the vibration of a piezoelectric transformer element, and to reduce misconnections such as disconnection of wire etc., by connecting the input/output electrodes of a piezoelectric transformer element and the terminal electrodes of a board with connecting members made of conductive elastic substance material. SOLUTION: The input electrodes 2, 2 and the output electrode 3 of a piezoelectric transformer element 10 are connected to terminal electrodes 22, 22, 23 formed on a board 20 by conductive elastic substances 6, 6, 6 respectively. For conductive elastic substances 6, conductive elastic materials such as conductive urethane rubber, conductive silicon rubber, conductive gel-like epoxy resin or silicone resin, etc., are used. Since the connection is made by the use of soft conductive elastic substances 6, and these conductive elastic substances 6 are expandable and contractable in accordance with the vibration of the piezoelectric transformer element 10, it becomes possible to reduce the suppression of the vibration, and to reduce misconnections such as disconnection of a wire.

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 for a backlight inverter of a liquid crystal display.

[0002]

2. Description of the Related Art Conventionally, as a piezoelectric transformer of this type, there is, for example, a structure shown in FIG. FIG. 2 (a)
Is a plan view of the piezoelectric transformer, and FIG. 2B is a side view.

This piezoelectric transformer is a piezoelectric transformer element 1.
0 is supported and placed on the substrate 20 by a supporting member 30 made of a rubber-like or gel-like adhesive, and the input / output electrodes 2 and 2 and the output electrode 3 of the piezoelectric transformer element 10 are lead wires 5 and 5, respectively. , And is connected to the terminal electrodes 22, 22, 23 formed on the substrate 20 through 5.

The piezoelectric transformer element 10 is provided with a piezoelectric plate 1 made of rectangular flat plate-shaped piezoelectric ceramics, and input electrodes 2 and 2 are formed on both main surfaces of one half of the piezoelectric plate 1 in the longitudinal direction so as to face each other. The output electrode 3 is formed on one end surface on the other side, the part where the input electrodes 2 and 2 on the input side are formed is polarized in the thickness direction, and the other half on the output side is polarized in the length direction. There is. An input electrode lead-out portion 2 that is electrically connected to the input electrodes 2 and 2 is formed on a part of both side surfaces of the portion where the input electrodes 2 and 2 are formed.
a and 2a are formed.

This piezoelectric transformer element 10 utilizes a basic (first-order) vibration mode called a λ / 2 mode, and its vibration has a vibration displacement at 1/2 (λ / 4) in the longitudinal direction. It becomes a so-called node point where it becomes zero, and the maximum displacement occurs at both ends.

A metal wire such as copper is used as the lead wire 5, and the portions corresponding to the node points of the input electrode lead-out portions 2a, 2a, the output electrode 3 and the terminal electrodes 22, 22, 2 of the substrate 20 are used.
Soldered to 3.

Then, by supporting and fixing with an adhesive having rubber-like or gel-like elasticity, stable support can be obtained without suppressing vibration.

[0008]

However, in the above-described conventional piezoelectric transformer, the input / output electrodes of the piezoelectric transformer element and the terminal electrodes of the substrate are connected by the lead wire of the metal wire, and the vibration is suppressed by the lead wire. There is a problem that the lead wire is broken due to the stress of vibration. In particular, there is a problem in that vibration suppression and disconnection in the lead wire connected to the output electrode becomes a problem, and electrical characteristics such as a boost ratio are deteriorated, or reliability of connection is deteriorated. That is, when a thick lead wire is used to prevent disconnection, vibration is significantly suppressed and desired characteristics cannot be obtained.

Further, the lead wire needs to be soldered to each electrode at both ends thereof, which increases the man-hours for connecting the input / output electrode and the terminal electrode, resulting in an increase in cost.

Therefore, an object of the present invention is to reduce vibration suppression, reduce connection failure such as disconnection, and reduce connection work man-hours. Therefore, a reliable and inexpensive piezoelectric transformer having good characteristics can be provided. To provide.

[0011]

In order to achieve the above object, the present invention provides a piezoelectric transformer element having an input electrode and an output electrode formed on a piezoelectric plate, and a plurality of terminals on which the piezoelectric transformer element is mounted. In a piezoelectric transformer including a substrate on which electrodes are formed and a connecting member that connects the input electrode or the output electrode to the terminal electrode, at least one of the connecting members is made of a conductive elastic material. It is a feature.

According to the above structure, since the input / output electrodes of the piezoelectric transformer element and the terminal electrodes of the substrate are connected by the conductive elastic material, that is, the flexible connecting member, the vibration of the piezoelectric transformer element is suppressed. Therefore, connection failure such as disconnection due to vibration is reduced.

Furthermore, since this connection can be performed by a simple method of applying a paste-like elastic material with a dispenser or the like, the number of connection work steps can be greatly reduced.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to the drawings showing embodiments thereof. In the figure, the same or corresponding parts as those in the conventional example are designated by the same reference numerals.

FIG. 1 shows the structure of a piezoelectric transformer according to an embodiment of the present invention. FIG. 1A is a plan view of the piezoelectric transformer,
FIG. 1B is a side view.

The piezoelectric transformer of this embodiment is basically (first order)
The vibration mode is used, and as shown in FIG. 1, the input / output electrodes 2 and 2 and the output electrode 3 of the piezoelectric transformer element 10 are used.
Are respectively connected to the terminal electrodes 22, 22, 23 formed on the substrate 20 by the conductive elastic bodies 6, 6, 6.

That is, in the present embodiment, the input / output electrodes 2, 2, 3 of the piezoelectric transformer element 10 and the terminal electrodes 22, 22, 23 formed on the substrate 20 are connected flexibly in place of conventional lead wires. A conductive elastic body 6 having properties is used.
The configuration other than the connecting member is the same as that described in FIG. 2 of the related art, and the description thereof is omitted.

As the conductive elastic body 6, a conductive elastic material such as conductive urethane rubber, conductive silicon rubber, conductive gel-like epoxy resin or silicon resin is used. The thickness of the support member 30 is 0.3 mm to 0.
It is set to 5 mm.

To form the conductive elastic body 6 (connection by the conductive elastic body 6), a paste-like conductive elastic body material is applied to the connection portion of each electrode by a dispenser or the like, and then several tens of degrees Celsius to 100 degrees. It is performed by curing at a temperature of several tens of degrees Celsius for about 30 minutes.

In the structure of this embodiment, the input / output electrodes of the piezoelectric transformer element and the terminal electrodes of the substrate are connected by a flexible conductive elastic body, and this conductive elastic body is used for vibration of the piezoelectric transformer element. Since it can be expanded and contracted accordingly, the suppression of vibration is reduced and the connection failure such as disconnection due to vibration is significantly reduced.

Furthermore, since the conductive elastic body can be formed by a simple method of applying and curing the paste-like elastic body material with a dispenser or the like, the number of connection work steps can be greatly reduced. When a rubber-like or gel-like resin adhesive is used as the support member as in this embodiment, the support member and the conductive elastic body can be applied and cured at the same time, which further reduces the number of work steps. be able to.

When a piezoelectric plate having a resonance frequency of about 83 KHz having a thickness of 1.9 mm is used and conductive urethane rubber (shear hardness 20 to 30) is used as a conductive elastic body, a copper plate having a diameter of 0.2 mmΦ is used. It was possible to obtain almost the same characteristics in the boost ratio and efficiency (input power / output voltage) as compared with the conventional one using the lead wire.

In the above-mentioned embodiment, the conductive elastic body is used for the connection between all the electrodes, but the invention is not limited to this. For example, only the connection of the output electrode, which is the maximum point of the vibration displacement, is conductive. A flexible elastic body may be used.

The material, material (hardness, etc.), coating amount, etc. of the conductive elastic body are set in consideration of the support structure of the piezoelectric transformer element and the relationship between the electrical characteristics and the reliability such as disconnection.

In the above embodiment, the basic vibration mode piezoelectric transformer element formed of a single piezoelectric plate has been described. However, a multi-layer substrate is used and the input / output electrodes of each layer are alternately connected at the end faces or side faces. It is needless to say that the present invention can be applied to the above-mentioned piezoelectric transformer element or the piezoelectric transformer element of the vibration mode of the second or higher order.

Further, other configurations are not limited to those of this embodiment. For example, the input electrode lead-out portion may be formed only in the portion to which the conductive elastic body is applied, and the piezoelectric transformer. The device support structure and the like are not limited to those in the above embodiment.

The substrate on which the piezoelectric transformer element is mounted may have an input / output signal processing circuit formed in addition to the input / output terminal electrodes.

[0028]

As described above, according to the piezoelectric transformer of the present invention, the input / output electrodes of the piezoelectric transformer element and the terminal electrodes of the substrate are connected by the conductive elastic material, that is, the flexible connecting member. Therefore, the vibration of the piezoelectric transformer element is not suppressed, and the connection failure such as the disconnection due to the vibration is reduced.

Furthermore, since this connection can be performed by a simple method of applying a paste-like elastic material with a dispenser or the like, the number of connection work steps can be greatly reduced.

Therefore, according to the present invention, it is possible to obtain an inexpensive piezoelectric transformer in which the deterioration of the connection portion due to vibration is reduced, the connection reliability is high, and the characteristics are good.

[Brief description of drawings]

1A is a plan view of a piezoelectric transformer according to an embodiment of the present invention, and FIG. 1B is a side view of FIG.

FIG. 2A is a plan view of a conventional piezoelectric transformer, and FIG.
FIG. 3 is a side view of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piezoelectric plate 2 Input electrode 2a Input electrode extraction part 3 Output electrode 6 Conductive elastic body 10 Piezoelectric transformer element 20 Substrate 22, 23 Terminal electrode 30 Support member

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takaaki Asada 2-26-10 Tenjin Tenjin, Nagaokakyo, Kyoto Prefecture Murata Manufacturing Co., Ltd. (72) Hideya Horiuchi 2-26-10 Tenjin Tenjin, Nagaokakyo, Kyoto Murata Manufacturing

Claims (1)

[Claims] 1. A piezoelectric transformer element in which an input electrode and an output electrode are formed on a piezoelectric plate, a substrate on which the piezoelectric transformer element is mounted and a plurality of terminal electrodes are formed, the input electrode or the output electrode, and A piezoelectric transformer comprising a connecting member for connecting to a terminal electrode, wherein at least one of the connecting members is made of a conductive elastic material.