JPH09283813A - Piezoelectric transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a piezoelectric transformer which does not release connections of lead wires, develops no breakdown of the lead wires and eases wiring. SOLUTION: This piezoelectric transformer comprises at least one input electrode 2, 3 and output electrode 4 on the surface of a rectangular piezoelectric ceramic board 1, a flexible insulation member 5 contg. a conductor 5a adhered to the surface of the board 1, the conductor 5a partly exposed at one end of the insulation member 5 is electrically connected to the output electrode 4 and that exposed at the other end is located at a node 11b of oscillation to form an output lead terminal 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high voltage DC / DC converter used for toner charging of a copying machine, a DC / A used for a liquid crystal backlight inverter, and the like.
The present invention relates to a piezoelectric transformer used in a C inverter.

[0002]

2. Description of the Related Art In static electricity generators, devices for lighting backlights of liquid crystal displays, etc., high voltage power supplies of IkV and several W are used.

At present, an electromagnetic transformer is used for boosting these power sources, but a piezoelectric transformer is put into practical use due to demands for reduction of generated electromagnetic noise, reduction of power consumption, and reduction in size and height of equipment. Has been done.

FIG. 2 is a perspective view showing an example of the structure of the piezoelectric transformer. As shown in FIG. 2, the piezoelectric ceramic rectangular plate 1 has about one half in the length direction from one end face.
Of the input electrodes 2 facing each other in the thickness direction over substantially the entire area of
And 3 are formed, and the output electrode 4 is formed on the side end face farther from the portion where the input electrodes 2 and 3 are formed.

Here, the portion between the input electrodes 2 and 3 is polarized in the thickness direction, and the portion between the output electrode 4 and the input electrodes 2 and 3 is polarized in the length direction.

The arrow indicates the polarization direction, which is 1 / m of the long axis.
It is shown that the positions of 4 and 3/4 have zero displacement and become nodes 11a and 11b.

3A and 3B are explanatory views of the operation principle of the piezoelectric transformer. FIG. 3A is a sectional view of the piezoelectric ceramic rectangular plate 1, and FIG. 3B is a diagram showing that the piezoelectric ceramic rectangular plate 1 vibrates in the longitudinal direction. FIG. 3C is a diagram showing the displacement distribution a when vibrating in the wavelength resonance mode, and FIG. 3C is a diagram showing the strain distribution b at that time.

In FIG. 3 (a), input electrodes 2 and 3 are provided.
When a voltage having a frequency equal to the resonance frequency of the one-wavelength resonance mode of longitudinal vibration is applied to the piezoelectric ceramic rectangular plate 1, the piezoelectric ceramic rectangular plate 1 has a displacement distribution a and a strain distribution b as shown in FIGS. 3 (b) and 3 (c). Draw and vibrate. At this time, a voltage is generated between the input electrodes 2 and 3 and the output electrode 4 by the piezoelectric effect.

[0009]

However, in the conventional piezoelectric transformer, in the case of the one-wavelength resonance mode as shown in FIG. 3, the extraction portion of the output lead terminal 9 for extracting the electric signal on the output side is vibrated. Other than the node 11b. Therefore, since the vibration of the take-out portion of the output lead terminal 9 is the largest, the bonding portion of the lead wire of the output lead terminal 9 is not loosened or broken, and the lead wire is not broken at the time of wiring. I had to be careful.

It is an object of the present invention to provide a piezoelectric transformer in which the connecting portion of the lead wire cannot be removed and the lead wire is not broken, and the wiring is easy.

[0011]

According to the present invention, in a piezoelectric transformer in which an input electrode and an output electrode are provided on the surface of a piezoelectric ceramic rectangular plate, a flexible insulating member including a conductor on the surface is provided. And the conductor exposed from one end of the insulating member is electrically connected to the output electrode, and the conductor exposed from the other end is placed at the position of the vibration node, and the output lead terminal is attached. It is possible to provide a piezoelectric transformer characterized by the following.

In the present invention, by using a flexible insulating member including a conductive wire, it is possible to take out an output lead wire for outputting an electric signal from the position of a vibration node of the piezoelectric transformer. Wiring is easy because the lead wire does not loosen or break.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a piezoelectric transformer of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic explanatory view of the structure of the piezoelectric transformer of the present invention. For example, when vibrating in the one-wavelength resonance mode as shown in FIG. 3B, the output electrode 4 becomes the antinode of vibration.

Therefore, as shown in FIGS. 1A and 1B, the conductor 5 is connected to the output electrode 4 by using the insulating member 5 made of a flexible sheet including the conductor 5a.
A is drawn to a portion corresponding to the node 8 of vibration, and the output lead terminal 9 is taken out therefrom.

In this embodiment, the insulating member 5 made of a flexible sheet is used in order to ensure more insulation.
A flexible substrate (hereinafter referred to as FPC) containing polyimide (insulator) was used.

Further, the output electrode 4 and the conductor 5a are electrically connected by using solder.

Since the FPC has an insulating structure, even if the FPC is in contact with the surface of the piezoelectric transformer, the piezoelectric effect occurs as before connecting the FPC between the input electrodes 2 and 3 and the output electrode 4. Further, the electrode can be taken out from the vibration node 8.

The FPC itself, as shown in FIG.
The conductor 5a exposed from the insulating member 5 is drawn out from the output electrode 4 provided on the short side end face in the long axis direction,
The conductor 5a and the output electrode 4 are connected and fixed by the solder 6, and the output lead terminal 9 made of a lead wire is electrically connected to the conductor 5a at the node 8 of the vibration of the piezoelectric transformer and penetrates the conductor 5a. The insulating member 5 is fixed by the adhesive 7.

[0020]

As described above, according to the present invention, a flexible insulating member having a linear conductor formed on its surface is adhered, and a terminal of one conductor of the flexible insulating member is bonded. By electrically connecting to the output electrode, arranging the terminal of the other conductor at the position of the node of vibration, and by making it an output lead terminal,
Since the connecting portion of the lead wire cannot be removed and the lead wire is not broken, it is possible to provide a piezoelectric transformer with easy wiring.

[Brief description of drawings]

FIG. 1 is a structural schematic explanatory view of a piezoelectric transformer of the present invention. FIG.
(A) is a perspective view showing a piezoelectric transformer of the present invention. FIG.
(B) is sectional drawing which shows the piezoelectric transformer of this invention. FIG.
FIG. 1C is a partially enlarged cross-sectional view of FIG.

FIG. 2 is a perspective view showing the structure of a piezoelectric transformer.

FIG. 3 is an explanatory diagram of an operation principle of a piezoelectric transformer. FIG. 3 (a)
Is a sectional view of a piezoelectric ceramic rectangular plate. FIG. 3B is a diagram showing a displacement distribution when the piezoelectric ceramic rectangular plate vibrates in the one-wavelength resonance mode of longitudinal vibration. FIG. 3C is a diagram showing a strain distribution in the case of FIG.

[Explanation of symbols]

 1 piezoelectric ceramic rectangular plate 2,3 input electrode 4 output electrode 5 insulating member 5a conductor 6 solder 7 adhesive 8 node 9 output lead terminal 10 input lead terminal 11a, 11b node a displacement distribution b strain distribution

Claims (1)

[Claims] 1. A piezoelectric transformer in which an input electrode and an output electrode are provided on a surface of a piezoelectric ceramic rectangular plate, and a flexible insulating member containing a conductor is bonded to the surface,
A conductor exposed from one end of the insulating member is electrically connected to the output electrode, and a conductor exposed from the other end is arranged at a vibration node position to form an output lead terminal. Characteristic piezoelectric transformer.