KR101685104B1 - Piezoelectric device and method of manufacturing the same - Google Patents

Abstract

The present invention relates to a piezoelectric laminate comprising a piezoelectric laminate in which a plurality of piezoelectric layers are laminated and a plurality of external electrodes are formed on at least one surface of the piezoelectric laminate, an FPCB for applying power to the piezoelectric laminate, And the other end of which is detachably coupled to the FPCB, and a method of manufacturing the same.

Description

[0001] The present invention relates to a piezoelectric device and a manufacturing method thereof,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to a piezoelectric device, and more particularly, to a piezoelectric device for bonding a piezoelectric laminate and a flexible printed circuit board (FPCB) and a manufacturing method thereof.

A piezoelectric substance is a substance having a property of converting electrical energy and mechanical energy applied thereto, and a plurality of such piezoelectric substance can be laminated to produce a piezoelectric substance laminate. The piezoelectric laminate can be used as a piezoelectric transformer, an ultrasonic vibrator, an electromechanical ultrasonic transducer, an ultrasonic motor, an actuator, a filter, a resonator, etc. which are widely applied to an ultrasonic device, a video device, a sound device, And is widely used as a material of these materials.

The piezoelectric laminate can be produced by preparing a plurality of thin piezoelectric sheets and then forming a predetermined type of internal electrodes on the piezoelectric sheet, laminating them, and then sintering the piezoelectric sheets at a predetermined temperature. A method of manufacturing such a piezoelectric laminate is disclosed in Korean Patent No. 10-1310626. Then, an external electrode is formed on at least one surface of the piezoelectric laminate, and then a predetermined voltage is applied to the external electrode so that a plurality of piezoelectric sheets are polarized in a predetermined direction. Subsequently, a flexible printed circuit board (hereinafter referred to as FPCB) is bonded to the piezoelectric laminate so that power can be externally applied to the piezoelectric laminate.

However, since the piezoelectric laminate of the related art has to bond the FPCB after sintering and polarizing the piezoelectric laminate, since the FPCB must be bonded at a low temperature, the FPCB is bonded using the epoxy which is cured at a low temperature. However, because the low-temperature curing epoxy has insulating properties, the piezoelectric laminate and the FPCB are insulated when the FPCB is bonded. Therefore, a high pressure is applied to press the piezoelectric laminate and the FPCB to bond.

However, a piezoelectric laminate produced by such a process may crack in a piezoelectric material due to pressure hardening. Further, since the insulating low-temperature curing epoxy has a low curing temperature, there may be a portion where the epoxy is not cured. If the epoxy is not completely cured, the bonding strength between the piezoelectric laminate and the FPCB is weak, so that the piezoelectric laminate and the FPCB can be separated. Therefore, power can not be supplied to the piezoelectric body laminate, resulting in malfunction or inoperability. In order to bond the piezoelectric laminate with the FPCB, the low-temperature high-pressure process is carried out for a long time for about one hour, so that the process time becomes long and the productivity may be deteriorated accordingly.

The present invention provides a piezoelectric device capable of preventing the occurrence of cracks in a piezoelectric body, improving the bonding force between the piezoelectric body and the FPCB, and reducing the processing time, and a method of manufacturing the piezoelectric device.

The present invention provides a piezoelectric device capable of bonding a piezoelectric body and an FPCB without using an insulating low-temperature curing epoxy and a method of manufacturing the piezoelectric device.

According to an aspect of the present invention, there is provided a piezoelectric device comprising: a piezoelectric laminate having a plurality of piezoelectric layers stacked on one another and having a plurality of external electrodes; An FPCB for applying power to the piezoelectric body laminate; And a connector, one end of which is detachably coupled to the piezoelectric laminate and connected to the external electrode, and the other end of which is coupled to the FPCB.

The connector includes a vertical portion facing the side surface of the piezoelectric body laminate, an upper clip formed in a direction in which the piezoelectric body laminate is provided from the upper portion of the vertical portion, and a lower clip formed in the same direction as the upper clip from the lower portion of the vertical portion. And an extension formed in at least one of the upper clip and the lower clip in a direction in which the FPCB is provided.

The upper clip is formed to have a predetermined slope in the one direction from the vertical portion, and the distal end portion is bent upward.

A piezoelectric laminate is inserted between the upper clip and the lower clip, and the FPCB is coupled to the extended portion.

The extension includes an upper extension extending from the upper clip and a lower extension extending from the lower clip.

A first power source for polarizing the piezoelectric laminate through the FPCB and the connector, and a second power source for driving the piezoelectric laminate are respectively applied.

According to another aspect of the present invention, there is provided a piezoelectric device comprising: a piezoelectric laminate having a plurality of piezoelectric layers stacked and having a plurality of external electrodes formed on at least one surface thereof; An FPCB for applying power to the piezoelectric body laminate; And a conductive adhesive layer provided between the piezoelectric layer laminate and the FPCB to bond and electrically connect them.

The FPCB includes a body, a plurality of circuit patterns formed on the body, a plurality of contact pads formed on one region of the body and in contact with the external electrodes, and a plurality of contact pads formed between the plurality of circuit patterns and the plurality of contact pads And a plurality of connection pads provided.

And a first power source for polarization of the piezoelectric layer laminate is applied through the plurality of connection pads and the plurality of contact pads.

And a connection unit for connecting at least two of the plurality of connection pads to each other.

A plurality of circuit patterns, a connection pad connected to at least two of the plurality of circuit patterns, and a plurality of contact pads are connected to a second power source for driving the piezoelectric layer stack.

According to an aspect of the present invention, there is provided a method of manufacturing a piezoelectric device, comprising: providing a piezoelectric laminate having a plurality of external electrodes on at least one side thereof; and an FPCB for applying power to the piezoelectric laminate; Applying a first power source for polarization of the piezoelectric layer laminate through an external electrode of the piezoelectric layer laminate; Inserting the piezoelectric laminate into one end of the connector and coupling the piezoelectric laminate to the other end of the connector; And applying a second power for driving the piezoelectric laminate through the FPCB and the connector.

According to another aspect of the present invention, there is provided a method of manufacturing a piezoelectric device, comprising: providing a piezoelectric laminate having a plurality of external electrodes on at least one side thereof; and an FPCB for applying power to the piezoelectric laminate; Forming an electroconductive adhesive layer on the external electrode of the piezoelectric layer laminate and bonding the electroconductive adhesive layer to the FPCB; Applying a first power source for polarization of the piezoelectric layer laminate through the FPCB; Connecting at least a portion of the conductive path of the FPCB to each other; And applying a second power source for driving the piezoelectric laminate through the FPCB to which at least a part of the conductive path is connected.

The FPCB includes a plurality of contact pads that are in contact with the external electrodes in a first region of the body, a plurality of connection pads connected to the plurality of contact pads in a second region of the body, A plurality of circuit patterns selectively connected to the plurality of contact pads are formed in the three regions.

The first power source is applied through a plurality of connection pads.

The step of connecting at least a part of the conductive paths of the FPCBs connects at least two of the plurality of connection pads to each other.

The second power source is applied through a plurality of circuit patterns.

The piezoelectric device according to an embodiment of the present invention may include a connector between the piezoelectric laminate and the FPCB to electrically connect the piezoelectric laminate and the FPCB. That is, one end of the connector is fastened to the piezoelectric laminate in a clipped manner, and the other end of the connector can be fastened to the FPCB in a clipped manner. Thus, a second power source for driving the piezoelectric laminate can be applied through the FPCB connected using the connector.

Further, in the piezoelectric device according to another embodiment of the present invention, a conductive adhesive layer is provided between the piezoelectric laminate and the FPCB, so that the piezoelectric laminate and the FPCB can be electrically connected. A first power source for polarization of the piezoelectric laminate and a second power source for driving can be applied through the FPCB connected thereto. Also, at least two of the plurality of conductive paths of the FPCB may be connected to each other before the second power for driving is applied.

Therefore, since no high pressure is applied to bond the piezoelectric laminate and the FPCB, cracks are not generated in the piezoelectric laminate. Further, since the piezoelectric laminate and the FPCB are electrically connected to each other through the connector, there arises no problem of malfunction or inoperability in the case of using a conventional insulating low-temperature curing adhesive. Since the low-temperature and high-pressure process for bonding the piezoelectric laminate and the FPCB is not performed for a long time, the process time is shortened and the productivity can be improved accordingly.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 and FIG. 2 are schematic diagrams of a piezoelectric device according to an embodiment of the present invention. FIG.
3 is a schematic view of a connector of a piezoelectric device according to an embodiment of the present invention;
FIG. 4 and FIG. 5 are schematic diagrams illustrating the separation and connection of a piezoelectric device according to another embodiment of the present invention. FIG.
6 is a schematic view of an FPCB of a piezoelectric device according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of other various forms of implementation, and that these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know completely.

FIG. 1 and FIG. 2 are schematic views showing the separation and connection of a piezoelectric device according to an embodiment of the present invention. 3 is a schematic view of a connector according to an embodiment of the present invention. FIG. 3 (a) is a perspective view of a connector, and FIG. 3 (b) is a cross-sectional view of a connector.

1 and 2, a piezoelectric device according to an embodiment of the present invention includes a piezoelectric laminate 100 in which a plurality of piezoelectric layers are laminated and formed with at least one external electrode 110, A connector 200 detachably coupled to the external electrode 110 of the stack 100 and an FPCB 300 coupled to the other end of the connector 200. [

The piezoelectric laminate 100 may be provided in a rectangular plate shape having a predetermined thickness, for example. That is, the piezoelectric laminate 100 may be provided with two opposite surfaces, that is, upper and lower surfaces, and four sides along the edges of the upper surface and the lower surface. Of course, the piezoelectric laminate 100 may be formed in various shapes such as a circle, an ellipse, and a polygon as well as a square. Such a piezoelectric laminate 100 may include a substrate and a piezoelectric layer formed on at least one surface of the substrate. For example, the piezoelectric laminate 100 may be formed of a bimorph type having a piezoelectric layer on both sides of a substrate, or a unimorph type having a piezoelectric layer formed on one side of the substrate. At least one layer of the piezoelectric layer may be laminated, and preferably, a plurality of piezoelectric layers may be laminated. Internal electrodes may be formed on the upper and lower portions of the piezoelectric layer, respectively. Here, the piezoelectric layer can be formed using, for example, a piezoelectric material of PZT (Pb, Zr, Ti), NKN (Na, K, Nb), BNT (Bi, Na, Ti) Further, the piezoelectric layers can be polarized in different directions and stacked. That is, when a plurality of piezoelectric layers are formed on one surface of the substrate, the piezoelectric layers may be alternately polarized in opposite directions. On the other hand, the substrate can be made of a material having characteristics such that vibration can be generated while maintaining a laminated structure of the piezoelectric layers. For example, metal, plastic, or the like can be used. At least one end of the substrate may be provided with an electrode terminal to which a driving voltage is applied. Incidentally, the piezoelectric laminate 100 may not use a piezoelectric layer and a substrate which is a foreign substance. That is, the piezoelectric layered product 100 is provided with a piezoelectric layer which is not polarized at the central portion, and a plurality of piezoelectric layers polarized in different directions on the upper and lower portions thereof can be laminated. In addition, the external electrode 110 is formed on at least one surface of the piezoelectric laminate 100. The external electrode 110 may be formed by patterning after forming a conductive layer on at least one surface of the piezoelectric laminate 100. For example, the external electrode 110 may have a predetermined shape by patterning after printing a conductive paste. The external electrodes 110 may be formed on one side of the piezoelectric laminate 100 and may be separated from each other at a central portion of one side of the piezoelectric laminate 100. For example, the external electrodes 110 may be separated from each other on the upper surface of the piezoelectric laminate 100. That is, the plurality of external electrodes 110 can be formed by removing the conductive material therebetween. At this time, one external electrode 110 may be formed on the upper surface of the piezoelectric laminate 110 as a whole. The external electrode 110 is connected to the internal electrode of the piezoelectric laminate 100 so that the first power source for polarization of the piezoelectric layer and the second power source for operating the piezoelectric laminate 100 are applied. For example, the first and third external electrodes 110a and 110c may be alternately connected to the internal electrodes between the piezoelectric bodies on the upper side of the substrate of the piezoelectric laminate 100, and the second and fourth external electrodes The electrodes 110b and 110d may be alternately connected to internal electrodes between the piezoelectric bodies on the lower side of the substrate. In order to connect the external electrode 110 with the internal electrode, a hole filled with a conductive material may be formed in a predetermined region of the piezoelectric bodies in the piezoelectric body laminate 110.

The connector 200 is provided to connect the FPCB 300 with the external electrode 110 of the piezoelectric laminate 100. The connector 200 is detachable from the piezoelectric laminate 100 and is provided to be coupled to the FPCB 300. The connector 200 supplies power supplied through the FPCB 300 to the piezoelectric laminate 100 so that copper or the like can be made of a conductive material. The connector 200 may be provided with two external electrodes 110, respectively. For example, the connector 200 may be separated from a portion connected to the first and second external electrodes 110a and 110 and a portion connected to the third and fourth external electrodes 110c and 110d. Of course, the connector 200 may be made of one piece so that the two parts may be insulated. 3, the connector 200 includes a vertical portion 210 corresponding to a side surface of the piezoelectric laminate 100 and a plurality of horizontal portions 210 extending in the horizontal direction from the upper portion and the lower portion of the vertical portion 210 in the piezoelectric laminate 100 direction. And an extension 240 extending from the upper clip 220 and the lower clip 230 in the FPCB 300 direction. That is, the upper clip 220 and the lower clip 230 are provided in the one direction from the vertical part 210, and the extended part 240 is provided in the opposite direction from the upper clip 220. Here, the piezoelectric laminate 100 is inserted into a space between the upper clip 220, the lower clip 230 and the vertical portion 210. That is, the piezoelectric laminate 100 may be inserted between the upper clip 220 and the lower clip 230 so that the side surface can be in contact with the inner surface of the vertical portion 210.

The structure of the connector 200 will be described in more detail as follows. The vertical portion 210 may be provided at a height corresponding to the thickness of the piezoelectric laminate 100. The distance between the upper clip 220 and the lower clip 230 is determined according to the height of the vertical portion 210 so that the pressure by the upper clip 220 and the lower clip 230 is determined. The vertical portion 210 may be provided at a height of about the thickness of the piezoelectric laminate 100 in order to stably fix the piezoelectric laminate 100 by the upper clip 220 and the lower clip 230 . Of course, the height of the vertical part 210 may be lower or higher than the thickness of the piezoelectric laminate 100. [ However, if the height of the vertical part 210 is too low, the pressure between the upper clip 220 and the lower clip 230 increases, but the contact area of the upper clip 220 with the piezoelectric laminate 100 may become narrower If the height of the vertical part 210 is too high, the pressure between the upper clip 220 and the lower clip 230 may be reduced and the piezoelectric laminate 100 may not be stably fixed. On the other hand, the area of the vertical part 210 passing through the extension part 240 can be removed. That is, the vertical portion 210 may be formed by removing at least one region, and the extending portion 240 may extend in the other direction through the removed region of the vertical portion 210.

The upper clip 220 may have a predetermined width in one direction from the upper side of the vertical portion 210. That is, the upper clip 220 is provided toward the piezoelectric laminate 100 and may be provided with the width of the external electrode 110 of the piezoelectric laminate 100. In addition, the upper clip 220 may be provided to correspond to the number of the external electrodes 110. For example, since four external electrodes 110 are provided, four upper clips 220 can be provided. Also, each of the four upper clips 220 may be insulated, and at least two regions may be insulated. On the other hand, the upper clip 220 has protrusions at least partially protruding in the direction of the piezoelectric laminate 100, i.e., in the downward direction, for more complete contact with the piezoelectric laminate 100. For example, the upper portion of the upper clip 210, which is in contact with the four external electrodes 110 of the piezoelectric laminate 100, may be formed with protrusions which are recessed from the upper side and convexly protruded when viewed from the inside. These protrusions can press the outer electrode 110 of the piezoelectric laminate 100 to increase the contact force between the outer electrode 110 and the upper clip 220 so that the upper clip 220 contacts the outer electrode 110 110 in contact with each other. In addition, the upper clip 220 may be formed such that an end portion thereof opposite to the vertical portion 210 is lifted upward to facilitate insertion of the piezoelectric laminate 100. That is, when the upper clip 220 is horizontal, it may be difficult to insert the piezoelectric laminate 100. Therefore, the upper end of the upper clip 220 into which the piezoelectric laminate 100 is inserted, that is, And can be manufactured in the form of a cylinder.

The lower clip 230 may have a predetermined width from the lower side of the vertical part 210 to the same direction as the upper clip 220. The lower clip 230 serves to support the piezoelectric laminate 100 and the upper clip 220 may serve to apply pressure to the piezoelectric laminate 100. Of course, both the upper clip 220 and the lower clip 230 may apply pressure to the piezoelectric laminate 100. The lower clip 230 may have the same width as the upper clip 220 and may have a width greater than or less than the width of the upper clip 230. When the lower clip 230 is narrower than the upper clip 220, the piezoelectric laminate 100 may be detached, so that the lower clip 230 is preferably equal to or larger than the upper clip 220 Do.

The extended portion 240 extends from one region of the upper clip 220 through the vertical portion 210 and extends in the opposite direction to the upper clip 220 and the lower clip 230. The extension 240 may be connected to the FPCB 300 in a manner such as SMT or solder. In addition, the extension 240 may be provided in a clip shape. That is, an upper extension extending from the upper clip 220 and a lower extension extending from the lower clip 230. Therefore, the FPCB 300 may be inserted between the upper extension part and the lower extension part to be connected to the FPCB. A protrusion protruding downward may be formed at the end of the extension 240. That is, protrusions formed concavely when viewed from above and protruding downward when viewed from the inside can be formed. Such a protrusion can improve the bonding force with the FPCB 300.

When the piezoelectric laminate 100 is inserted between the upper clip 220 and the lower clip 230, at least one of the upper clip 220 and the lower clip 230 is inserted into the piezoelectric laminate 100 So that the piezoelectric laminate 100 is bonded with pressure. For example, the lower clip 230 contacts and fixes to the lower side of the piezoelectric laminate 100, and the upper clip 220 applies pressure to the upper side of the piezoelectric laminate 100. At this time, when the piezoelectric laminate 100 is inserted, the front ends of at least one of the upper clip 220 and the lower clip 230 are slightly lifted so that the upper clip 220 and the lower clip 230 are pressed against the piezoelectric laminate 100). At least one of the upper clip 220 and the lower clip 230 may be provided to have a predetermined slope from the vertical portion 210 to generate or further increase the pressure applied to the piezoelectric laminate 100 . For example, the lower clip 230 may be kept horizontal, and the upper clip 220 may be provided to have a predetermined inclination from the vertical portion 210 so that an end portion of the upper clip 220, The lower clip 230 remains in contact with the lower clip 230. In this state, when the piezoelectric laminate 100 is inserted between the upper clip 220 and the lower clip 230, a pressure is generated between the upper clip 220 and the lower clip 230 by the tension of the upper clip 220 And is bonded to the piezoelectric laminate 100.

The FPCB 300 has a structure in which a plurality of conductive paths are formed on at least one surface of an insulating film. The FPCB 300 is connected to the other end of the connector 200. That is, the FPCB 300 may be connected to the extension portion 240 of the connector 200 by a method such as SMT or soldering. The FPCB 300 may apply a second power for driving the piezoelectric laminate 100. That is, the piezoelectric device of the present invention applies a first power source through the external electrode 110 of the piezoelectric laminate 100 to perform polarization treatment of the piezoelectric laminate 100, and then, by using the connector 200, The piezoelectric laminate 100 can be driven by connecting the water 100 and the FPCB 300 and then supplying the second power through the FPCB 300. [ At this time, the second power source may be supplied from the output terminal of the electronic device after the FPCB 300 is connected to an electronic device such as a smart phone.

As described above, the piezoelectric device according to the embodiment of the present invention is provided with the connector 200 between the piezoelectric laminate 100 and the FPCB 300, so that the piezoelectric laminate 100 and the FPCB 300 can be electrically connected to each other have. That is, one end of the connector 200 is fastened to the piezoelectric laminate 100 in a clip manner, and the other end of the connector 200 is fastened to the FPCB 300 in a joining manner or a clip. Thus, the second power source for driving the piezoelectric laminate 100 can be applied through the FPCB 300 connected using the connector 200. Therefore, no high pressure is applied to the piezoelectric laminate 100 and the FPCB 300, so that cracks are not generated in the piezoelectric laminate 100. In addition, since the piezoelectric laminate 100 and the FPCB 300 are electrically connected to each other through the connector 200, there is no problem of malfunction or inoperability in the case of using the conventional insulating low-temperature curing adhesive. Since the low-temperature and high-pressure process for bonding the piezoelectric layered product 100 and the FPCB 300 is not performed for a long time, the process time is shortened and the productivity can be improved accordingly.

FIGS. 4 and 5 are schematic views illustrating the separation and connection of a piezoelectric device according to another embodiment of the present invention, and FIG. 6 is a schematic view of an FPCB of a piezoelectric device according to another embodiment of the present invention. Here, FIG. 6A is a schematic view of the FPCB when the first power source for polarization is applied, and FIG. 6B is a schematic view of the FPCB when the second power source is applied for the operation.

4 and 5, a piezoelectric device according to another embodiment of the present invention includes a piezoelectric laminate 100 having a plurality of piezoelectric layers stacked and having external electrodes 110 formed on at least one surface thereof, An FPCB 300 coupled to the external electrodes 110 of the laminate 100 and a conductive adhesive layer 400 provided between the piezoelectric layered product 100 and the FPCB 300 to bond them. That is, in the piezoelectric device according to another embodiment of the present invention, the piezoelectric laminate 100 and the FPCB 300 can be bonded by the conductive adhesive layer 400. The piezoelectric layered product 100 may be polarized by the first power source supplied through the FPCB 300 after being coupled to the FPCB 300 by the conductive adhesive layer 400 and may be supplied through the FPCB 300 And can be operated by a second power source. In the following description, contents overlapping with the embodiment of the present invention will be omitted.

As the conductive adhesive layer 400, a conductive adhesive agent can be used. The conductive adhesive may be provided in the form of a paste and may be applied on the external electrode 110 of the piezoelectric laminate 100. The conductive adhesive agent may be one in which conductive particles containing a metal material are dispersed in a binder resin or the like. Here, the conductive particles may be at least one selected from gold, silver, aluminum, copper, nickel, silver coated with silver, nickel coated with silver, and copper coated with nickel. However, the kinds of the conductive particles are not limited to these, and silver is preferably coated with silver in consideration of economy and conductivity. On the other hand, the content of the conductive particles is preferably 50 to 200 parts by weight based on 100 parts by weight of the total binder resin. If the content of the conductive particles is less than 50 parts by weight based on 100 parts by weight of the total binder resin, the conductive particles can not be electrically connected to each other, so that the conductive path can not be formed in the binder resin, Tangling is caused between the conductive particles, which is not preferable because it causes the resistance of the conductive particles to increase during the conductive operation. The binder resin of the conductive adhesive may be at least one of a urethane resin and an epoxy resin. That is, a conductive adhesive can be prepared by mixing electrically conductive particles in a urethane resin or an epoxy resin, and conductive particles can be mixed in a mixture of a urethane resin and an epoxy resin. On the other hand, the conductive adhesive layer 400 may be a conductive adhesive film. As the conductive adhesive film, a conductive adhesive composition in which conductive particles are dispersed in a binder resin may be used on a release substrate containing conductive particles. The conductive adhesive layer 400 may have a curing temperature of 110 ° C to 200 ° C. That is, another embodiment of the present invention can perform a high-temperature curing process because the conductive adhesive layer 400 is combined with the FPCB 300 before the piezoelectric layered product 100 is polarized, May be cured at a high temperature to be completely cured, so that a high-pressure process may not be performed.

6A, the FPCB 300 includes a body 310 and a plurality of contacts (not shown) connected to the plurality of external electrodes 110 of the piezoelectric laminate 100, respectively, A plurality of contact pads 320 and a plurality of circuit patterns 330 connected to an external power supply unit to apply power through a plurality of contact pads 320, And a plurality of connection pads 340 provided between the first and second connection pads 330 and 330. For example, the number of the external electrodes formed on the piezoelectric laminate 100, for example, four, may be provided for the contact pads 320, the number of the contact pads 320, And four can be provided. In addition, the circuit pattern 330 may be provided in a number smaller than the number of the contact pads 320 and the connection pads 340, for example, two. The body 310 may be made flexible and insulating, and may be made of an insulating plastic film such as polyimide or polyester. The body 310 may include a first region corresponding to a plurality of external electrodes 110 of the piezoelectric laminate 100 and having a predetermined width and length and a second region connected to a predetermined region of the first region. have. Here, a plurality of contact pads 320 may be formed in the first region, and a plurality of connection pads 340 and circuit patterns 330 may be formed in the second region. The plurality of contact pads 320 are formed in the first region of the body 310 and are respectively connected to the plurality of external electrodes 110 of the piezoelectric laminate 100 by the conductive adhesive layer 400. The plurality of circuit patterns 330 are formed in the second region of the body 320 and are connected to an external power supply. This circuit pattern 330 is used to supply power for driving the piezoelectric laminate 100. [ The plurality of connection pads 340 are formed between the plurality of contact pads 320 and the plurality of circuit patterns 330 to connect the plurality of contact pads 320 with each other. For example, the first circuit pattern 330a is connected to the first connection pad 340a and the second circuit pattern 330b is connected to the fourth connection pad 340d. The first connection pad 340a is connected to the first contact pad 320a, the second connection pad 340b is connected to the second contact pad 320b, and the third connection pad 340c is connected to the third contact pad 320b. And the fourth connection pad 340d is connected to the fourth contact pad 320d. The plurality of contact pads 320, the circuit patterns 330 and the connection pads 340 are formed on the body 310 by exposing, developing, and etching the copper clad laminate produced by, for example, laminating thin copper . For example, a plurality of contact pads 320 may be formed on the lower layer, a plurality of connection pads 340 may be formed on the upper layer, a plurality of circuit patterns 330 may be formed on the upper layer, May be formed on the plurality of layers. The FPCB 300 may be used to apply a first power for polarization of the piezoelectric layer 100 and a second power for driving. For example, a first power source for polarization is applied through a plurality of connection pads 340. That is, the terminal of the external power source contacts the plurality of connection pads 340, and the first power for polarization is applied to the plurality of contact pads 320 through the plurality of connection pads 340. For example, positive power may be applied to the second and fourth connection pads 330b and 330d, and (-) power may be applied to the first and third connection pads 330a and 330c. However, at least two of the connection pads 330 may be connected to each other after the first power for polarization is applied. For example, the first and second connection pads 340a and 340b may be connected, and the third and fourth connection pads 340c and 340d may be connected. At this time, as shown in FIG. 6 (b), at least two connection pads 340 may be connected by connection portions 350a and 350b using solder or the like. The first and second connection pads 340a and 340b may be connected by the first connection portion 350a and the third and fourth connection pads 340c and 340d may be connected by the second connection portion 350b. have. After this connection, a second power source for driving is applied through the circuit pattern 330. 6B, the first and second connection pads 340a and 340b are connected to receive the positive power from the first circuit pattern 330a, and the third and fourth connection The pads 340c and 340d may be connected and a negative power may be applied from the second circuit pattern 330b.

As described above, the piezoelectric device according to another embodiment of the present invention is provided with the conductive adhesive layer 400 between the piezoelectric laminate 100 and the FPCB 300, so that the piezoelectric laminate 100 and the FPCB 300 are electrically connected . That is, the conductive adhesive layer 400 is formed on the external electrode 110 of the piezoelectric layered product 100, the FPCB 300 is provided on the conductive adhesive layer 400 and then thermally cured to form the piezoelectric layered product 100 and the FPCB 300 can be bonded. A first power source for polarization of the piezoelectric laminate 100 and a second power source for driving may be applied through the FPCB 300 connected thereto. At least two of the plurality of connection pads 340 of the FPCB 300 may be connected to each other before the second power for driving is applied. Therefore, no high pressure is applied to bond the piezoelectric laminate 100 and the FPCB 300, so that cracks are not generated in the piezoelectric layered product 100. In addition, since the piezoelectric laminate 100 and the FPCB 300 are electrically connected to each other by using the conductive adhesive layer 400, there is no problem of malfunction or inoperability. Since the low-temperature and high-pressure process for bonding the piezoelectric layered product 100 and the FPCB 300 is not performed for a long time, the process time is shortened and the productivity can be improved accordingly.

A method of manufacturing a piezoelectric device according to another embodiment of the present invention will now be described.

A piezoelectric raw material powder is prepared. Piezoelectric powders commercially available for industrial use may be used, or raw material powders of a desired piezoelectric ceramic composition such as PZT and PLZT may be used. A PVB binder as an additive to the piezoelectric raw material powder is well mixed with an alcohol or the like and mixed and milled and mixed with a ball mill for about 24 hours to prepare a slurry . Then, the slurry is subjected to a doctor blade or the like to produce a piezoelectric sheet having a desired shape and thickness.

Internal electrodes are formed on one surface and the other surface of the thus-prepared piezoelectric sheet. The inner electrode may be formed by a thick film deposition method such as screen printing using conductive paste such as Pd, Ag / Pd, or Ag. The internal electrode may be formed by a thin film deposition method such as sputtering, evaporation, chemical vapor deposition, sol-gel coating, or the like. On the other hand, a plurality of holes may be formed in at least one piezoelectric sheet selected before the internal electrode is formed on the piezoelectric sheet, and a conductive material may be embedded in the holes.

A desired number of piezoelectric sheets having internal electrodes are laminated, and then cut into piezoelectric devices to produce a piezoelectric laminate for a unit device. Here, it is possible to stack a plurality of piezoelectric sheets on which a substrate is provided at the center and internal electrodes are respectively formed on one surface and the other surface of the substrate. Subsequently, the piezoelectric laminate is heated to a temperature of, for example, 230 to 350 DEG C to bake-out all the binder components in the piezoelectric laminate, and is then sintered at a sintering temperature of, for example, 700 to 900 DEG C, The laminate is sintered.

Then, an external electrode is formed on at least one surface of the piezoelectric laminate. Here, the external electrode may be formed by a thick film deposition method such as screen printing or a thin film deposition method such as sputtering, evaporation, chemical vapor deposition, and sol-gel coating.

Then, a conductive adhesive layer is formed on the external electrode of the piezoelectric laminate. The conductive adhesive layer may be a conductive adhesive in which the conductive particles are mixed with the binder resin.

Then, the FPCB is provided on the piezoelectric laminate on which the conductive adhesive is applied. Here, the FPCB includes a plurality of contact pads which are in contact with external electrodes of the piezoelectric laminate on a flexible and insulating film such as polyimide, a plurality of connection pads for applying a first power for external polarization to the contact pads, And a plurality of circuit patterns for applying a second power for driving may be formed. Next, the piezoelectric device is cured by, for example, curing at a temperature of 110 ° C to 200 ° C to bond the piezoelectric laminate and the FPCB.

Then, a first power source is applied from the outside, and a plurality of piezoelectric sheets in the piezoelectric laminate can be polarized. The first power source may be applied to a plurality of contact pads through a plurality of connection pads.

Then, at least two of the plurality of connection pads are connected by, for example, solder. For example, connect two of each of the four connecting pads by soldering. Subsequently, after the piezoelectric device is provided in the electronic device, the second power source is applied from the electronic device, causing the piezoelectric substance laminate to vibrate.

Although the technical idea of the present invention has been specifically described according to the above embodiments, it should be noted that the above embodiments are for explanation purposes only and not for the purpose of limitation. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention.

100: piezoelectric laminate 200: connector
300: FPCB 400: conductive adhesive layer

Claims (17)

A piezoelectric laminate having a plurality of piezoelectric layers stacked and a plurality of external electrodes formed on at least one surface thereof;
An FPCB for applying power to the piezoelectric body laminate; And
And a connector, one end of which is detachably coupled to the piezoelectric laminate and connected to the external electrode, and the other end of which is coupled to the FPCB,
The connector includes an upper clip and a lower clip into which the piezoelectric laminate is inserted,
And an upper extension portion and a lower extension portion, respectively extending from the upper and lower clips in a direction in which the FPCB is provided, into which the FPCB is inserted,
Wherein the upper clip is formed to have a predetermined slope in the direction of the piezoelectric laminate.
The connector according to claim 1, wherein the connector further includes a vertical portion opposed to a side surface of the piezoelectric layer laminate,
Wherein the upper clip and the lower clip are formed in a direction in which the piezoelectric laminate is provided from the upper and lower portions of the vertical portion.
The piezoelectric device according to claim 2, wherein the upper clip has a shape in which the distal end portion is bent upward.
delete delete The piezoelectric transducer according to claim 3, wherein a first power source for polarizing the piezoelectric laminate is applied via the external electrodes of the piezoelectric laminate, and a second power source for driving the piezoelectric laminate through the FPCB and the connector after the connector is connected, A piezoelectric device to which power is applied.
delete delete delete delete delete A manufacturing method of a piezoelectric device according to any one of claims 1, 2, 3 and 6,
Providing a piezoelectric laminate having a plurality of external electrodes on at least one side thereof and an FPCB for applying power to the piezoelectric laminate;
Applying a first power source for polarization of the piezoelectric layer laminate through an external electrode of the piezoelectric layer laminate;
Inserting the piezoelectric laminate into one end of the connector and coupling the piezoelectric laminate to the other end of the connector; And
And applying a second power for driving the piezoelectric laminate through the FPCB and the connector.
delete delete delete delete delete

Images