KR20050000886A - Piezo-electric transformer with symmetric and asymmetric electrode structures - Google Patents

Abstract

PURPOSE: A piezoelectric transducer is provided to obtain high efficiency in piezoelectric transformation from the same surface area, to control easily the frequency and to reduce the size by forming symmetrically and/or asymmetrically internal electrodes between stacked ceramic sheets. CONSTITUTION: A ceramic stack structure(20) composed of a plurality of ceramic sheets(CS1-CSN) is formed on an insulating dummy layer(DLB). An uppermost insulating dummy layer(DLT) is formed on the ceramic stack structure. A plurality of inner input electrodes(IIE) are asymmetrically formed on upper left portions of the ceramic sheets, respectively. A plurality of inner common electrodes(ICE) are formed on lower left portions of the ceramic sheets corresponding to the inner input electrodes. A plurality of inner output electrodes(IOE) are symmetrically formed on upper right portions of the ceramic sheets.

Description

Piezoelectric transformers with symmetrical and asymmetrical electrode structures {PIEZO-ELECTRIC TRANSFORMER WITH SYMMETRIC AND ASYMMETRIC ELECTRODE STRUCTURES}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to piezoelectric transformers applicable to power supplies such as camcorders, mobile phones, LCD TVs, monitors, notebooks, and the like. In particular, internal electrodes between a plurality of laminated ceramic sheets are symmetrically and / or asymmetrically formed to increase frequency. The present invention relates to a piezoelectric transformer having a symmetrical and asymmetrical electrode structure capable of controlling the impedance to be determined, that is, the capacitance, thereby achieving high efficiency in the same area, facilitating control of frequency, and miniaturizing with the same performance. .

In general, a piezo-electric transformer is a device that converts electrical energy into mechanical energy by using a material having a piezoelectric effect, or converts mechanical energy back into electrical energy. If the electromechanical coupling coefficient is high, the mechanical quality factor is deteriorated, and thus practical use has not been made because of low weakening force and low boost ratio (output / input).

By the way, in recent years, a device having a high boost ratio has been developed and mainly used for high voltage power supply for TV, and is used for electric dust collector, powder coating machine, electronic copying machine, high pressure degassing device, especially mobile phone, LCD TV and monitor, notebook It is applied to DC high voltage power supply, such as an apparatus.

1 is a diagram illustrating an electrode connection structure of a general piezoelectric transformer.

Referring to FIG. 1, a general piezoelectric transformer is formed by stacking a plurality of ceramic sheets. Each ceramic sheet includes an internal input electrode formed on a left side of an upper surface, an internal common electrode formed on a left side of a lower surface thereof, and an upper surface thereof. It includes an internal output electrode formed at the right end of the. An internal input electrode formed on each ceramic sheet is connected, an internal common electrode formed on each of the plurality of ceramic sheets is connected, and an internal output electrode formed on each of the plurality of ceramic sheets is connected.

When a voltage is input to the input electrode and the common electrode of the piezoelectric transformer, the input voltage is boosted by the boost ratio of the piezoelectric transformer and then output through the output electrode and the common electrode. At this time, the input voltage is converted into mechanical vibration in the piezoelectric transformer, the mechanical vibration is provided to the output voltage through the process of being converted into electrical energy again.

Two representative modes of operation of the piezoelectric transformer operating as described above are lambda / 2 mode and lambda mode, which will be described with reference to FIG.

FIG. 2 is a stress and strain distribution diagram of a vibration mode of a general piezoelectric transformer. FIG. 2 (a) shows a strain distribution diagram in a λ / 2 mode, and FIG. 2 (b) shows a stress distribution diagram in a λ mode. have.

Important characteristics considered in such piezoelectric transformers include high efficiency, electromechanical coupling characteristics, mechanical quality characteristics, linearity of input / output voltage, shift of resonant frequency and output voltage by supporting point, and temperature characteristic of resonant frequency. In recent years, according to the trend of miniaturization of electronic products, it is necessary to be able to exhibit performance while minimizing as much as possible, and to have appropriate strength.

3 is an external perspective view of a conventional piezoelectric transformer.

Referring to FIG. 3, a conventional piezoelectric transformer includes a ceramic laminate structure 10 in which a plurality of ceramic sheets are stacked between dummy layers DLT and DLB at an uppermost portion thereof. An external input electrode OIE, an external common electrode OCE, and an external output electrode OOE are formed on the side surface thereof.

4 is a laminated structure diagram of a conventional piezoelectric transformer.

Referring to FIG. 4, the conventional piezoelectric transformer includes a laminated structure 10 in which a plurality of ceramic sheets are stacked between the lowermost dummy layers DLT and DLB, and the plurality of piezoelectric transformers included in the laminated structure 10 are included. Each of the ceramic sheets includes an internal input electrode IIE formed at the left side of the upper surface, an internal common electrode ICE formed at the left side of the lower surface thereof, and an internal output electrode IOE formed at the right end of the upper surface thereof. do. The conventional piezoelectric transformer is manufactured by laminating and sintering a plurality of ceramic sheets. In such a piezoelectric transformer, a voltage input between the external input electrode and the common electrode is converted into mechanical vibration, and the mechanical vibration is converted into a voltage again to appear between the external output electrode and the common electrode.

In such a conventional piezoelectric transformer, a plurality of ceramic sheets are stacked, each of which includes internal electrodes formed of the same sized area, that is, internal input electrodes of each ceramic time are the same size, and internal common The electrodes are the same size as each other, and the internal output electrodes are the same size as each other.

By the way, the driving frequency in the piezoelectric transformer is closely related to the length of each ceramic sheet, and as the frequency increases, the length becomes short and vice versa. In addition, also in the power-up ratio of the piezoelectric transformer, the more ceramic sheets to be laminated, the higher, which is limited when the thickness is limited.

However, since each of the ceramic sheets included in the conventional piezoelectric transformers has the same vertical symmetrical structure as the internal electrodes, the piezoelectric transformers having the same size have almost the same frequency characteristics. There is a problem that can not control the impedance to determine the. Accordingly, since the size for obtaining the desired frequency is determined, it is impossible to further reduce the size of the frequency, and thus, the piezoelectric transformer of a specific size is impossible to control impedance and frequency, and the same performance cannot be further reduced. have.

The present invention has been proposed to solve the above problems, and an object thereof is to form an internal electrode between a plurality of laminated ceramic sheets mutually symmetrically and / or asymmetrically to control impedance, that is, capacitance which determines frequency. The present invention provides a piezoelectric transformer having a symmetrical and asymmetric electrode structure that can achieve high efficiency in the same area, control frequency easily, and can be miniaturized with the same performance.

1 is a diagram illustrating an electrode connection structure of a general piezoelectric transformer.

2 is a stress and strain distribution diagram of a vibration mode of a general piezoelectric transformer.

3 is an external perspective view of a conventional piezoelectric transformer.

4 is a laminated structure diagram of a conventional piezoelectric transformer.

5 is an external perspective view of a piezoelectric transformer according to the present invention.

6 is a laminated structure diagram of a piezoelectric transformer according to the present invention.

7 is an explanatory diagram of a capacitance control concept according to the present invention.

Explanation of symbols on the main parts of the drawings

DLT: Upper dummy layer DLB: Lower dummy layer

CS1-CSN: Ceramic Sheet IIE: Internal Input Electrode

ICE: Internal Common Electrode IOE: Internal Output Electrode

OIE: External Input Electrode OCE: External Common Electrode

OOE: External Output Electrode

In order to achieve the above object of the present invention, the piezoelectric transformer of the present invention

An insulating dummy layer;

A ceramic laminated structure in which a plurality of ceramic sheets are stacked on the dummy layer and has a top surface, left and right sides, and a front and back side surface;

An uppermost insulating dummy layer laminated on an upper surface of the ceramic laminated structure;

A plurality of internal input electrodes including a plurality of electrodes formed in a conductive pattern on a left side of an upper surface of each ceramic sheet of the stacked structure, wherein an area of at least one of the plurality of electrodes is different from that of other electrodes;

A plurality of internal common electrodes formed in a conductive pattern at a position corresponding to the internal input electrodes formed on the upper surface of the ceramic sheet, among the lower surfaces of the ceramic sheets;

A plurality of internal output electrodes formed in a conductive pattern on a right end of an upper surface of each ceramic sheet;

An external input electrode electrically connected to the internal input electrode and formed in a conductive pattern on a portion of a rear surface of the ceramic laminate structure;

An external common electrode electrically connected to the internal common electrode and formed in a conductive pattern on a portion of a front side of the ceramic laminate structure; And

An external output electrode electrically connected to the internal output electrode and formed of a conductive pattern on a portion of the front and rear sides of the ceramic laminate structure

It characterized by having a.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

5 is an external perspective view of a piezoelectric transformer according to the present invention.

Referring to FIG. 5, in the piezoelectric transformer according to the present invention, an insulating dummy layer DLB and a plurality of ceramic sheets CS1 -CSN are stacked on the dummy layer DLB to form top, left, and front and rear sides. And a ceramic laminated structure 20 having the uppermost insulating dummy layer DLT stacked on an upper surface of the ceramic laminated structure.

6 is a laminated structure diagram of a piezoelectric transformer according to the present invention.

5 and 6, the piezoelectric transformer includes a plurality of electrodes formed in a conductive pattern on a left side of an upper surface of each ceramic sheet of the multilayer structure, and an area of at least one of the plurality of electrodes may be A plurality of internal common electrodes formed in a conductive pattern at positions corresponding to the internal input electrodes IIE formed differently from the areas of the other electrodes and the lower surface of each ceramic sheet, and the internal input electrodes formed on the upper surface of the ceramic sheet; An electrode (ICE), a plurality of internal output electrodes (IOE) formed in a conductive pattern at a right end of the upper surface of each ceramic sheet, and electrically connected to the internal input electrodes (IIE), An external input electrode OIE formed in a conductive pattern on a portion of a side surface thereof, and electrically connected to the internal common electrode ICE, and a part of a front side of the ceramic laminate structure An external common electrode (OCE) formed in a conductive pattern on the substrate, and an external output electrode (OOE) electrically connected to the internal output electrode (IOE), and formed in a conductive pattern on a portion of the front and rear sides of the ceramic laminate structure.

Here, the positions where the external electrodes are formed may be changed in consideration of the applied product, and the positions where the external input electrodes and the external common electrodes are formed may be changed, respectively, and the formation positions of the external output electrodes may be changed. Do.

7 is an explanatory diagram of a capacitance control concept according to the present invention.

Referring to FIG. 7, in the piezoelectric transformer described above, an internal capacitance C for determining a resonance frequency Fr may include an area A of each of an internal input electrode and an internal common electrode of each ceramic sheet, and each ceramic. It is determined by the distance d between the internal input electrode and the internal common electrode of the sheet. Accordingly, each of the plurality of internal common electrodes is preferably formed to have the same area as the internal input electrode formed on the upper surface of the ceramic sheet. Do. Here, the resonant frequency is represented by Equation 1 below, and the capacitance is represented by Equation 2 below.

Among the factors for determining the operating frequency, in the present invention, the areas of the internal input electrodes formed on the plurality of ceramic sheets are formed symmetrically with each other, but the areas of some of the internal input electrodes are formed asymmetrically with each other. In order to control the capacitance and the frequency according to the change of the area.

Accordingly, an area of at least one internal output electrode of the plurality of output electrodes is formed differently from that of other internal output electrodes, which will be described in detail below.

An area of at least one internal input electrode of the plurality of internal input electrodes is larger than an area where no conductive pattern is formed on the top surface of the ceramic sheet, and other internal input electrodes are formed on the top surface of the ceramic sheet. It can be formed substantially the same as the unformed area. For example, an area of at least one internal input electrode of the plurality of internal input electrodes may be formed up to 3/5 or 4/7 points of the total length L of the corresponding ceramic sheet, and at this time, another internal input The area of the electrodes can be formed up to one half of the total length of the ceramic sheet.

In addition, an area of at least one of the plurality of internal input electrodes may be smaller than that of the conductive pattern on the top surface of the ceramic sheet, and the other internal input electrodes may be formed on the top surface of the ceramic sheet. The conductive pattern may be formed to be substantially the same as the area where the conductive pattern is not formed. For example, an area of at least one internal input electrode of the plurality of internal input electrodes may be formed up to 2/5 or 3/7 points of the total length of the ceramic sheet, and at this time, the area of the other internal input electrodes Up to half of the total length of the ceramic sheet can be formed.

In addition, an area of at least one of the plurality of internal input electrodes may be smaller than that of the conductive pattern on the top surface of the ceramic sheet, and the other internal input electrodes may be formed on the top surface of the ceramic sheet. The conductive pattern may be formed larger than the area where the conductive pattern is not formed. For example, an area of at least one internal input electrode of the plurality of internal input electrodes may be formed up to 2/5 or 3/7 points of the total length of the ceramic sheet, and at this time, the area of the other internal input electrodes It can be formed up to 2/5 or 3/7 points of the total length of the ceramic sheet.

The area of at least one of the plurality of internal input electrodes may be greater than that of the conductive pattern on the top surface of the ceramic sheet, and the other internal input electrodes may be formed on the top surface of the ceramic sheet. In the conductive pattern may be formed larger than the area is not formed. For example, an area of at least one of the plurality of internal input electrodes may be formed up to 3/5 or 4/7 points of the total length of the ceramic sheet, and at this time, the area of the other internal input electrodes It can be formed up to 3/5 or 4/7 points of the total length of the ceramic sheet.

As described above, in the piezoelectric transformer of the present invention, even if the size is determined, the area of the internal input electrode can be formed differently for each ceramic sheet even in the predetermined size, so that the desired capacitance can be controlled to thereby achieve a desired resonance frequency. Will be obtained.

According to the present invention as described above, in piezoelectric transformers applicable to power supplies such as camcorders, mobile phones, LCD TVs and monitors, notebook computers, internal electrodes between a plurality of laminated ceramic sheets are formed symmetrically and / or asymmetrically. By controlling the impedance to determine the frequency, that is, the capacitance, the high efficiency can be obtained in the same area, the frequency can be easily controlled, and the miniaturization can be performed with the same performance.

The above description is only a description of specific embodiments of the present invention, and the present invention is not limited to these specific embodiments, and various changes and modifications of the configuration are possible from the above-described specific embodiments of the present invention. It will be apparent to those skilled in the art to which the present invention pertains.

Claims (7)

An insulating dummy layer (DLB); A ceramic laminated structure in which a plurality of ceramic sheets CS1 -CSN are stacked on the dummy layer DLB, and having a top surface, left and right sides, and a front and rear side surface; An uppermost insulating dummy layer (DLT) stacked on an upper surface of the ceramic laminated structure; A plurality of electrodes formed in a conductive pattern on the left side of the upper surface of each ceramic sheet of the laminated structure, wherein the area of at least one of the plurality of electrodes is different from the area of other electrodes ( IIE); A plurality of internal common electrodes ICE formed in a conductive pattern at a position corresponding to the internal input electrodes formed on the upper surface of the ceramic sheet, among the lower surfaces of the ceramic sheets; A plurality of internal output electrodes (IOE) formed in a conductive pattern on the right end of the upper surface of each ceramic sheet; An external input electrode OIE electrically connected to the internal input electrode IIE and formed in a conductive pattern on a portion of a rear surface of the ceramic laminate structure; An external common electrode (OCE) electrically connected to the internal common electrode ICE and formed in a conductive pattern on a portion of the front side of the ceramic laminate structure; And An external output electrode (OOE) electrically connected to the internal output electrode (IOE) and formed in a conductive pattern on a portion of the front and back sides of the ceramic multilayer structure. Piezoelectric transformer characterized in that it comprises a. The method of claim 1, wherein each of the plurality of internal common electrodes A piezoelectric transformer, characterized in that formed to equal the area of the internal input electrode formed on the upper surface of the ceramic sheet. The method of claim 1, wherein the area of at least one internal output electrode of the plurality of output electrodes is A piezoelectric transformer, characterized in that formed differently from the area of the other internal output electrodes. The method of claim 1, wherein an area of at least one internal input electrode of the plurality of internal input electrodes is On the upper surface of the ceramic sheet is formed larger than the area where the conductive pattern is not formed, The other internal input electrodes A piezoelectric transformer, characterized in that formed on the upper surface of the ceramic sheet substantially the same as the area where the conductive pattern is not formed. The method of claim 1, wherein an area of at least one internal input electrode of the plurality of internal input electrodes is In the upper surface of the ceramic sheet is formed smaller than the area where the conductive pattern is not formed, The other internal input electrodes A piezoelectric transformer, characterized in that formed on the upper surface of the ceramic sheet substantially the same as the area where the conductive pattern is not formed. The method of claim 1, wherein an area of at least one internal input electrode of the plurality of internal input electrodes is In the upper surface of the ceramic sheet is formed smaller than the area where the conductive pattern is not formed, The other internal input electrodes A piezoelectric transformer, characterized in that formed on the upper surface of the ceramic sheet larger than the area where the conductive pattern is not formed. The method of claim 1, wherein an area of at least one internal input electrode of the plurality of internal input electrodes is On the upper surface of the ceramic sheet is formed larger than the area where the conductive pattern is not formed, The other internal input electrodes Piezoelectric transformer, characterized in that formed on the upper surface of the ceramic sheet larger than the area where the conductive pattern is not formed.