KR20110024210A - Piezoelectric element and piezoelectric buzzer and piezoelectric buzzer module using thereof and fabrication method thereof - Google Patents

Abstract

PURPOSE: A piezoelectric element, a piezoelectric buzzer using the same and a piezoelectric buzzer module thereof, a method for manufacturing method thereof are provided to have a structure which can apply a reflow process without soldering process. CONSTITUTION: A piezoelectric element manufactured by a simple reflow process, a piezoelectric buzzer using the same, piezoelectric buzzer module, and a manufacturing method thereof are comprised as follows. A first electrode(110) and second electrode(120) are respectively attached to both sides of piezoelectric buzzer. The second electrode is being expanded to an opposite surface and electrode expanded unit(121) is separately placed to the first electrode and is formed on piezoelectric element. A vibration plate(200) is adhered to a second electrode of a piezoelectric element and is accepted to a piezoelectric element and vibration plate inside. A first element(310) and second element(320) are included in a case.

Description

Piezoelectric element and piezoelectric buzzer module using piezoelectric element and piezoelectric buzzer module and method for manufacturing same using piezoelectric element and piezoelectric buzzer module

The present invention relates to a piezoelectric element, a piezoelectric buzzer and a piezoelectric buzzer module using the same, and a method of manufacturing the same. More specifically, a piezoelectric element, a piezoelectric buzzer and a piezoelectric buzzer module using the same, and a method of manufacturing the same can be manufactured without a soldering process. It is about.

In general, a piezoelectric element refers to an element having a characteristic of changing electrical energy and mechanical energy from each other, and a piezoelectric buzzer converts mechanical movement of the piezoelectric element acoustically by a metal diaphragm and through a case having a resonance structure. It is a representative product of acoustic components that can resonate at a desired frequency.

At this time, as piezoelectric elements, thin film piezoelectric ceramics with electrodes attached to both surfaces are generally used, and piezoelectric buzzers attach piezoelectric ceramic thin plates to a thin metal diaphragm to attach the electrodes to both sides of the piezoelectric ceramic thin plates. The sound pressure is generated by stretching and vibrating in a direction perpendicular to the electric field according to the electric field generated therebetween.

In order to manufacture the piezoelectric buzzer, first, the piezoelectric ceramic thin plates used for the piezoelectric buzzer are polarized in the thickness direction, and then electrodes are formed on both surfaces of the polarized piezoelectric ceramic thin plates. The piezoelectric ceramic thin plate on which the electrode is formed is attached to the metal diaphragm, and then the piezoelectric buzzer is assembled by putting the piezoelectric ceramic thin plate and the metal diaphragm into an acoustically designed case and assembling an acoustic oscillation circuit board.

However, in the related art, when the piezoelectric element is coupled to the case and when the case is coupled to the acoustic oscillation circuit board, a coupling process by soldering is performed, thereby reducing work efficiency.

In addition, there is a limitation in the method of manufacturing the piezoelectric buzzer because it is vulnerable to high temperature as the case of forming the piezoelectric buzzer is easily polymerized.

The present invention has been made to solve the above problems, a piezoelectric element, a piezoelectric buzzer and a manufacturing method and a piezoelectric buzzer manufactured using a simple reflow process having a structure that can be applied to the reflow process without a soldering process It provides a module and a method of manufacturing the same.

A piezoelectric element according to a preferred embodiment of the present invention is a piezoelectric element for a piezoelectric buzzer, comprising: a piezoelectric ceramic thin plate which is polarized in the thickness direction and at least one via hole penetrates both surfaces thereof; And a first electrode and a second electrode attached to both surfaces of the piezoelectric ceramic thin plate, respectively, wherein the second electrode extends to an opposite surface to form an electrode extension part spaced apart from the first electrode.

At least one via hole penetrating both surfaces is formed in the piezoelectric ceramic sheet, the first electrode is attached to one surface of the piezoelectric ceramic sheet, and the second electrode is attached to the other surface of the piezoelectric ceramic sheet, and the electrode extension part is formed through the via hole. It extends integrally with the second electrode.

In addition, the piezoelectric buzzer according to the preferred embodiment of the present invention has a first electrode and a second electrode attached to both surfaces thereof, and the second electrode extends to the opposite surface to form an electrode extension part spaced apart from the first electrode. An element; A diaphragm adhered to the second electrode of the piezoelectric element; The piezoelectric element and the diaphragm are accommodated therein, and include a case having a first terminal and a second terminal in contact with electrode extensions of the first electrode and the second electrode.

The piezoelectric element may be formed in a plate shape polarized in a thickness direction, and may include a piezoelectric ceramic thin plate having via holes penetrating both sides, and an electrode extension of the second electrode may be formed on the opposite side of the piezoelectric ceramic thin plate through the via hole. It is characterized in that extending to.

The case may include an element seating end in which the piezoelectric element is mounted, and the first terminal and the second terminal may be spaced apart from each other.

The case may include an opening portion formed in one direction, and at least one sound hole communicating with the inside and the outside of the case may be formed to cover the opening of the case.

The case and the cover portion are formed of a ceramic material.

The first electrode and the electrode extension portion and the first terminal and the second terminal are bonded by a conductive epoxy resin.

In addition, in the piezoelectric buzzer module according to the preferred embodiment of the present invention, first and second electrodes are respectively attached to both surfaces thereof, and the second electrode extends to the opposite surface to form an electrode extension part spaced apart from the first electrode. A piezoelectric element; A diaphragm adhered to the second electrode of the piezoelectric element; The piezoelectric element and the diaphragm are accommodated therein, and include a case having a first terminal and a second terminal contacting the electrode extensions of the first electrode and the second electrode, wherein the first terminal and the second terminal are provided. Each of the outer periphery of the case portion extends to form the first external electrode portion and the second external electrode portion, and the first external electrode portion and the second external electrode portion includes a circuit board mounted by the SMT process.

The piezoelectric buzzer manufacturing method according to a preferred embodiment of the present invention forms a first electrode and a second electrode on both surfaces, and the second electrode extends to the opposite surface to be spaced apart from the first electrode. Preparing a piezoelectric element having; Bonding a diaphragm to a surface on which the second electrode of the piezoelectric element is formed; Preparing a case having a first terminal and a second terminal therein; Coupling the piezoelectric element to a case by seating on the first terminal and the second terminal, respectively, so that the electrode extension of the first electrode and the second electrode of the piezoelectric element is electrically connected.

In the step of coupling the piezoelectric element to the case, it is characterized in that the extension of the first electrode and the second electrode is bonded to the first terminal and the second terminal with a conductive epoxy resin, respectively.

In addition, the method of manufacturing a piezoelectric buzzer module according to a preferred embodiment of the present invention forms a first electrode and a second electrode on both sides, and the second electrode extends to the opposite side to be spaced apart from the first electrode Preparing a piezoelectric element having a portion; Bonding a diaphragm to a surface on which the second electrode of the piezoelectric element is formed; Preparing a case having a first external electrode portion and a second external electrode portion provided therein with a first terminal and a second terminal and extending the first terminal and the second terminal to one of the outer circumferential surfaces; Coupling the piezoelectric element to a case by seating on the first terminal and the second terminal, respectively, so that the electrode extension of the first electrode and the second electrode of the piezoelectric element is electrically connected; Preparing by applying solder paste or solder cream to the circuit board; Arranging a case to seat a first external electrode part and a second external electrode part on the solder paste or solder cream; And mounting the case on a circuit board by performing an SMT process in which a reflow temperature higher than the melting temperature of the solder paste or solder cream and lower than 300 ° C. is applied.

According to an exemplary embodiment of the present invention, one of two electrodes attached to both surfaces of the piezoelectric ceramic thin plate may be extended to the other surface to simplify the coupling process between the diaphragm and the case.

In addition, the bonding process may be simplified by bonding the conductive epoxy resin to the piezoelectric element and the case without using a soldering process.

Further, since the piezoelectric element and the case are formed of a ceramic material having no soldering and having good heat resistance, the SMT process can be applied when the case and the circuit board are coupled, and thus the piezoelectric buzzer can be easily and quickly mounted.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention in more detail. It will be apparent to those skilled in the art that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know. Like numbers refer to like elements in the figures.

1 is a view showing a piezoelectric element according to the present invention, Figure 2 is a perspective view showing a piezoelectric buzzer according to the present invention, Figure 3 is an exploded perspective view showing a piezoelectric buzzer according to the present invention, Figure 4 is according to the present invention 5 is an exploded cross-sectional view showing a piezoelectric buzzer according to the present invention, and FIG. 6 is a cross-sectional view showing a piezoelectric buzzer module according to the present invention.

As shown in the drawing, the piezoelectric buzzer according to the present invention includes a piezoelectric element 100; A diaphragm 200 bonded to one side of both surfaces of the piezoelectric element 100; The case 300 includes a case in which the piezoelectric element 100 and the diaphragm 200 are accommodated. The piezoelectric buzzer module according to the present invention includes the case 300, that is, the circuit board 600 on which the piezoelectric buzzer is mounted.

First, the piezoelectric element 100 will be described with reference to FIG. 1. In FIG. 1, (a) is a top view, (b) is a bottom view, (c) is sectional drawing.

The piezoelectric element 100 includes a piezoelectric ceramic thin plate 101, a first electrode 110 attached to one surface of the piezoelectric ceramic thin plate 101, and a second electrode attached to the other surface of the piezoelectric ceramic thin plate 101. 120).

The piezoelectric ceramic thin plate 101 is a means having a piezoelectric characteristic by being polarized in the thickness direction, and is formed of a substantially rectangular thin plate in this embodiment. The shape of the piezoelectric ceramic thin plate 101 may be variously changed without being limited to the exemplary embodiment provided that the piezoelectric properties that may be applied to the piezoelectric buzzer are formed. In this case, at least one via hole 101a penetrating both surfaces is formed in the body of the piezoelectric ceramic thin plate 101. For example, the via hole 101a may be formed in one or a plurality of slot shapes penetrating the piezoelectric ceramic thin plate 101 or may be formed in one or a plurality of circular shapes. In addition, the via hole 101a is not limited to penetrating the piezoelectric ceramic thin plate 101 in a straight line, and may be variously bent to penetrate the piezoelectric ceramic thin plate 101.

The first electrode 110 and the second electrode 120 are respectively attached to both surfaces of the piezoelectric ceramic thin plate 101. In this case, the second electrode 120 extends to one surface of the piezoelectric ceramic thin plate 101 through the via hole 101a to form an electrode extension 121 spaced apart from the first electrode 110. Therefore, it is preferable that the electrode extension 121 of the first electrode 110 and the second electrode 120 are formed at the same height on one surface of the piezoelectric ceramic thin plate 101.

The diaphragm 200 is a means for acoustically converting a mechanical signal generated by an electrical signal applied to the piezoelectric ceramic thin plate 101, and is made of a thin metal plate. The diaphragm 200 is attached to the other surface of the piezoelectric ceramic thin plate 101, that is, the surface to which the second electrode 120 is attached. Therefore, it is preferable that the electrode extension part 121 of the first electrode 110 and the second electrode 120 is disposed on one surface of the piezoelectric ceramic thin plate 101, and the diaphragm 200 is disposed on the other surface.

 The case 300 is a means for amplifying an acoustic signal generated by the diaphragm 200, and is a housing accommodating the piezoelectric element 100 and the diaphragm 200. The case 300 is a substantially rectangular enclosure, and has an opening formed on an upper surface thereof, and a resonance structure for resonating an acoustic signal generated from the diaphragm 200 by forming an empty space therein. Of course, the shape of the case 300 is not limited to the rectangular housing, but the resonance structure capable of accommodating the piezoelectric element 100 and the vibration plate 200 therein and resonating an acoustic signal generated from the vibration plate 200. It may be implemented in various shapes having a.

In this case, an element mounting end 331 in which the piezoelectric element 100 is mounted is formed in the case 300. The device seating end 331 may be implemented in various ways, but in the present embodiment, a pair is formed on both sides of the interior of the enclosure. In addition, each device seating end 331 is provided with the first terminal 310 and the second terminal 320 so as to be spaced apart from each other for electrical contact with the piezoelectric element 100. In this case, the first terminal 310 and the second terminal 320 are provided with electrode extensions 121 of the first electrode 110 and the second electrode 120 provided on one surface of the piezoelectric element 100. It is disposed corresponding to the area. Thus, the piezoelectric element 100 is seated on the element mounting end 331 so that the first electrode 110 of the piezoelectric element 100 contacts the first terminal 310 and the electrode of the second electrode 120. The extension 121 is in contact with the second terminal 320. In this case, the first electrode 110, the electrode extension 121, the first terminal 310, and the second terminal 320 may be adhered by the conductive epoxy resin 500. The device seating end 331 may be formed on both sidewalls of the case 300 as shown in this embodiment, but may be variously implemented. For example, it may be implemented in a protrusion shape which is entered in the upper direction from the bottom surface of the case 300.

Each of the first terminal 310 and the second terminal 320 has one or both ends of the first external electrode part 311 and the second external electrode part bent so as to extend through the sidewalls of the case 300 to the bottom surface thereof. 321 is formed. At this time, the first external electrode portion 311 and the second external electrode portion 321 may be exposed to any surface of the case 300, but when the case 300 and the circuit board 600 are combined, the SMT ( Surface Mount Technology) is preferably exposed to the same side in order to apply the process.

In addition, a cover seating end 333 is formed inside the upper edge of the case 300. Thus, as the cover seating end 333 is seated, the cover 400 covering the opening of the case 300 is configured.

At least one sound hole 410 communicating with the inside and the outside of the case 300 is formed in the cover part 400. The sound hole 410 may be emitted to the outside of the case 300 by controlling the frequency of the sound signal generated from the diaphragm 200 by appropriately adjusting the diameter. For example, as the size of the sound hole 410 increases, a sound signal in a low frequency region is generated, and as the size of the sound hole 410 becomes smaller, a sound signal in a high frequency region is generated.

In addition, the case 300 and the cover part 400 are preferably formed of a ceramic material. Thus, when the case 300 and the circuit board 600 are coupled in an SMT process, the case 300 and the cover part 400 are prevented from being damaged or deformed by the reflow temperature.

The circuit board 600 described above is a means for supplying electricity to the piezoelectric element 100 to generate sound, and the first external electrode part 311 and the second exposed to the outside of the case 300. A solder bump 610 on which the external electrode part 321 is mounted is formed. Thus, as the case 300 is mounted on the solder pump 610 of the circuit board 600 through the first external electrode part 311 and the second external electrode part 321, the circuit board 600 and the piezoelectric element ( 100 is electrically connected.

Referring to the manufacturing process of the piezoelectric buzzer configured as described above are as follows.

First, the piezoelectric element 100 is prepared. The piezoelectric element 100 polarizes the piezoelectric ceramic thin plate 101 in the thickness direction, and then attaches the first electrode 110 and the second electrode 120 to both surfaces thereof. The second electrode 120 extends to the opposite surface through the via hole 101a formed in the piezoelectric ceramic thin plate 101 to form an electrode extension 121 spaced apart from the first electrode 110. .

Then, the diaphragm 200 is attached to a surface on which the second electrode 120 of the piezoelectric element 100 is attached.

In addition, the case 300 in which the piezoelectric element 100 and the diaphragm 200 are accommodated is prepared. In this case, an element seating end 331 on which the piezoelectric element 100 is mounted is formed in the case 300, and a first electrode 110 and a second electrode of the piezoelectric element 100 are mounted on the element seating end 331. The electrode extension 121 of the electrode 120 has a first terminal 310 and a second terminal 320 which are in direct contact with each other. In addition, one or both ends of each of the first terminal 310 and the second terminal 320 may be bent to extend through the sidewall of the case 300 to the lower surface of the first external electrode part 311 and the second external electrode. The part 321 is formed.

When the case 300 is prepared as described above, the piezoelectric element 100 having the diaphragm 200 is coupled to the case 300. In this case, the piezoelectric element is configured such that the first electrode 110 of the piezoelectric element 100 contacts the first terminal 310 and the electrode extension 121 of the second electrode 120 contacts the second terminal 320, respectively. The device 100 is seated. Preferably, the electrode extensions 121 of the first electrode 110 and the second electrode 120 are adhered to the first terminal 310 and the second terminal 320 with a conductive epoxy resin 500, respectively. .

In addition, the inside and the outside of the case 300 are blocked by covering the opening formed in the case 300 with the cover part 400 having the sound hole 410, except the sound hole 410 formed in the cover 400.

When the piezoelectric element 100 and the diaphragm 200 are coupled inside the case 300, the case 300 is mounted on the circuit board 600 by a surface mount technology (SMT) process. First, in order to form the solder bumps 610 on the circuit board 600, a solder paste or solder cream is coated, and then the first external electrode part 311 and the second external electrode part 321 of the case 300 are provided. The case 300 is mounted on the circuit board 600 such that the case 300 is disposed in the corresponding solder paste 610 or solder cream. Then, the case 300 is mounted on the circuit board 600 by soldering at a reflow temperature higher than the melting temperature of the solder paste or solder cream and lower than 300 ° C. At this time, when the reflow temperature is applied at 300 ° C. or higher, the polarization of the piezoelectric ceramic thin plate 101 is released, and the piezoelectric effect is lowered or lost. And if the lower limit of the reflow temperature is higher than the melting temperature of the applied solder paste or solder cream, any temperature may be applied. For example, in the case of a general solder paste or solder cream based on lead, it is preferable to apply the reflow temperature to about 250 ° C or higher.

Although described above with reference to the drawings and embodiments, those skilled in the art can be variously modified and changed within the scope of the invention without departing from the spirit of the invention described in the claims below. I can understand.

1 is a view showing a piezoelectric element according to the present invention,

2 is a perspective view showing a piezoelectric buzzer according to the present invention;

3 is an exploded perspective view showing a piezoelectric buzzer according to the present invention;

4 is a cross-sectional view showing a piezoelectric buzzer according to the present invention;

5 is an exploded cross-sectional view showing a piezoelectric buzzer according to the present invention;

6 is a cross-sectional view showing a piezoelectric buzzer module according to the present invention.

<Explanation of symbols for the main parts of the drawings>

100: piezoelectric element 101: piezoelectric ceramic thin plate

110: first electrode 120: second electrode

121: electrode extension 200: diaphragm

300: case 310: first terminal

311: first external electrode 320: second terminal

321: second external electrode 400: cover portion

410: sound hole 500: conductive epoxy resin

600: circuit board

Claims (12)

As a piezoelectric element for a piezoelectric buzzer, A piezoelectric ceramic thin plate which is polarized in the thickness direction and has at least one via hole penetrating both surfaces thereof; A first electrode and a second electrode attached to both surfaces of the piezoelectric ceramic thin plate, respectively, And the second electrode extends to an opposite surface to form an electrode extension part spaced apart from the first electrode. The method according to claim 1, The piezoelectric ceramic thin plate is formed with at least one via hole penetrating both sides, The first electrode is attached to one surface of the piezoelectric ceramic thin plate, the second electrode is attached to the other surface, the electrode extension portion is integrally extended with the second electrode through the via hole. A piezoelectric element having a first electrode and a second electrode attached to both surfaces thereof, respectively, wherein the second electrode extends to an opposite surface to form an electrode extension part spaced apart from the first electrode; A diaphragm adhered to the second electrode of the piezoelectric element; The piezoelectric buzzer includes a case accommodating the piezoelectric element and the diaphragm and having first and second terminals in contact with electrode extensions of the first and second electrodes. The method of claim 3, The piezoelectric element includes a piezoelectric ceramic thin plate formed in a plate shape polarized in a thickness direction and having via holes penetrating both surfaces thereof. And an electrode extension portion of the second electrode extending to the opposite surface of the piezoelectric ceramic sheet through the via hole. The method of claim 3, The case has a piezoelectric buzzer having a device seating end in which the piezoelectric element is mounted therein, and the first terminal and the second terminal being spaced apart from each other. The method of claim 3, The case has an opening formed in one direction, Piezoelectric buzzer including at least one sound hole is formed in communication with the inside and the outside of the case to cover the opening of the case. The method according to claim 6, The case and cover portion is a piezoelectric buzzer formed of a ceramic material. The method of claim 3, The piezoelectric buzzer is bonded to the first electrode and the electrode extension, the first terminal and the second terminal by a conductive epoxy resin. A piezoelectric element having a first electrode and a second electrode attached to both surfaces thereof, respectively, wherein the second electrode extends to an opposite surface to form an electrode extension part spaced apart from the first electrode; A diaphragm adhered to the second electrode of the piezoelectric element; And a case in which the piezoelectric element and the diaphragm are accommodated and provided with first and second terminals in contact with electrode extensions of the first and second electrodes, Each of the first terminal and the second terminal extends to one of the outer peripheral surfaces of the case part to form a first external electrode part and a second external electrode part. And a circuit board on which the first external electrode part and the second external electrode part are mounted by an SMT process. Forming a first electrode and a second electrode on both surfaces, respectively, and preparing the piezoelectric element having an electrode extension part spaced apart from the first electrode by extending to the opposite surface; Bonding a diaphragm to a surface on which the second electrode of the piezoelectric element is formed; Preparing a case having a first terminal and a second terminal therein; And coupling the piezoelectric element to a case by seating on the first terminal and the second terminal, respectively, so that the electrode extensions of the first electrode and the second electrode of the piezoelectric element are electrically connected. The method according to claim 10, In the step of coupling the piezoelectric element to the case, The extension portion of the first electrode and the second electrode is a piezoelectric buzzer manufacturing method of bonding to the first terminal and the second terminal with a conductive epoxy resin, respectively. Forming a first electrode and a second electrode on both surfaces, respectively, and preparing the piezoelectric element having an electrode extension part spaced apart from the first electrode by extending to the opposite surface; Bonding a diaphragm to a surface on which the second electrode of the piezoelectric element is formed; Preparing a case having a first external electrode portion and a second external electrode portion provided therein with a first terminal and a second terminal and extending the first terminal and the second terminal to one of the outer circumferential surfaces; Coupling the piezoelectric element to a case by seating on the first terminal and the second terminal, respectively, so that the electrode extension of the first electrode and the second electrode of the piezoelectric element is electrically connected; Preparing by applying solder paste or solder cream to the circuit board; Arranging a case to seat a first external electrode part and a second external electrode part on the solder paste or solder cream; And mounting the case on a circuit board by performing an SMT process to which a reflow temperature higher than the melting temperature of the solder paste or solder cream is applied and lower than 300 ° C. is applied.

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