JP5605433B2 - Piezoelectric vibration device - Google Patents

Description

  The present invention relates to a piezoelectric vibration device used for, for example, a piezoelectric actuator or a piezoelectric sounding body, and more particularly to a piezoelectric vibration device in which a piezoelectric element is bonded to a support member and uses a bending mode.

  Conventionally, piezoelectric vibration devices are used for piezoelectric actuators, piezoelectric sounding bodies, Haptics, and the like. An example of the piezoelectric sounding body is a piezoelectric speaker.

  The following Patent Document 1 discloses a piezoelectric vibration device used for a piezoelectric sounding body. In this piezoelectric vibration device, a plurality of piezoelectric vibrators are housed in a case. FIG. 17 is a partial enlarged cross-sectional view showing a main part of a part where a plurality of piezoelectric vibrators 1001 and 1002 are housed in a case 1003. Here, only a part of the case 1003 is shown. Piezoelectric vibrators 1001 and 1002 are housed in a housing portion 1003 a provided in the case 1003. The piezoelectric vibrators 1001 and 1002 are stacked via a spacer 1004. A clamp 1005 made of metal is attached so as to sandwich the piezoelectric vibrators 1001 and 1002 stacked on both sides of the spacer 1004. The piezoelectric vibrators 1001 and 1002 are sandwiched by the clamp 1005 and are electrically connected to the electrodes on the outer surface of the piezoelectric vibrators 1001 and 1002 by the clamp 1005. The other ends of the piezoelectric vibrators 1001 and 1002 are also supported by the same structure.

JP 2006-324893 A

  In the piezoelectric vibration device described in Patent Document 1, the clamp 1005 is used to electrically connect the piezoelectric vibrators 1001 and 1002. For this reason, it is possible to omit the bonding by the bonding wire.

  However, in the piezoelectric vibration device, when the thickness of the piezoelectric vibrators 1001 and 1002 is reduced, the piezoelectric vibrators 1001 and 1002 supported by being sandwiched by the clamp 1005 are generated when the piezoelectric vibration device is vibrated. Due to the vibration, stress concentrates on the portions where the piezoelectric vibrators 1001 and 1002 are supported, and there is a problem that the piezoelectric vibrators 1001 and 1002 are damaged or deformed.

  On the other hand, a method of electrically connecting the bonding wire to the drive electrode of the piezoelectric vibrator has been conventionally used. However, the bonding wire may come off at the bonding wire joining portion due to the vibration of the piezoelectric vibrator. Further, when the strength of the bonding portion of the bonding wire is increased, the piezoelectric vibrator may be damaged due to stress concentration due to the difference between the rigidity of the bonding material and the rigidity of the drive electrode of the piezoelectric vibrator. Further, the drive electrode and the wiring electrode may be peeled off.

  An object of the present invention is a piezoelectric vibration device using a piezoelectric element in which drive electrodes are formed on both main surfaces of a piezoelectric plate, and poor conduction in an electrically connected portion of the drive electrode hardly occurs. An object of the present invention is to provide a highly reliable piezoelectric vibration device that does not easily break and does not easily cause electrode peeling.

  The piezoelectric vibration device according to the present invention includes a piezoelectric body having first and second main surfaces facing each other, and a first main surface side of the piezoelectric body that is formed in parallel with the first main surface. 1 drive electrode, and on the second main surface side of the piezoelectric body, the second drive electrode is formed in parallel with the second main surface and is opposed to the first drive electrode, A region where the first and second drive electrodes are opposed to each other in the thickness direction of the piezoelectric body is an active region, and a region where the first drive electrode and the second drive electrode are not opposed is an inactive region. And a support member having a piezoelectric element bonding surface to which the piezoelectric element is bonded.

  In the present invention, the support member has a first wiring electrode that is formed on the piezoelectric element bonding surface and is electrically connected to the first drive electrode of the piezoelectric element.

  In the present invention, the first drive electrode of the piezoelectric element and the first wiring electrode of the support member are electrically connected, and the first main surface of the piezoelectric element is used as the support member and the piezoelectric element bonding surface. A first bonding material layer that is bonded is further provided.

  In a specific aspect of the piezoelectric vibration device according to the present invention, the piezoelectric element is formed on the first main surface of the piezoelectric body in the inactive region of the piezoelectric body, and is formed on the second main surface. And a connection electrode electrically connected to the two drive electrodes. The support member further has a second wiring electrode formed on the piezoelectric element bonding surface and electrically connected to the second drive electrode. Furthermore, a second bonding material layer is further provided for electrically connecting the connection electrode and the second wiring electrode and bonding the first main surface of the piezoelectric element to the piezoelectric element bonding surface of the support member. It has been. In this case, the piezoelectric element is firmly bonded to the piezoelectric element bonding surface using not only the first bonding material layer but also the second bonding material layer. At the same time, the first and second drive electrodes are electrically connected to the first and second wiring electrodes provided on the support member.

  In another specific aspect of the piezoelectric vibration device according to the present invention, the support member supports the support member from the outside so that when the piezoelectric element vibrates in the bending mode, the supporting member vibrates in the bending mode of the same frequency as the piezoelectric element. There is a bending mode support for the purpose. In this case, the piezoelectric element and the supporting member can be vibrated in the bending mode only by supporting the supporting member by the bending mode supporting portion from the outside as described above. Preferably, the bending mode support portion is located in a peripheral portion located outside the region to which the piezoelectric element is bonded, and the first wiring electrode reaches the peripheral portion. In this case, the first wiring electrode can be easily electrically connected to the outside.

  Preferably, at least the primary bending mode node of the support member is located in the bending mode support portion. In this case, vibration due to the bending mode is not easily inhibited.

  In still another specific aspect of the piezoelectric vibration device according to the present invention, the piezoelectric element further includes a protective layer formed on the first main surface of the piezoelectric body and made of an insulating material. The protective layer is bonded to the piezoelectric element bonding surface of the support member. In this case, the protective layer can surely prevent a short circuit between the first drive electrode and the second drive electrode on the first main surface side of the piezoelectric element. Further, the protective layer can firmly bond the piezoelectric element to the piezoelectric element bonding surface of the support member.

  In still another specific aspect of the piezoelectric vibration device according to the present invention, the piezoelectric element is formed on the second main surface of the piezoelectric body so as to cover the second drive electrode, and is made of an insulating material. It further has a layer. In this case, since the second drive electrode is covered with the protective layer, the second drive electrode can be prevented from coming into direct contact with the finger. Therefore, electric shock can be prevented.

  In still another specific aspect of the piezoelectric vibration device according to the present invention, the protective layer is made of the same material as the piezoelectric body. In this case, a piezoelectric vibration device provided with a protective layer can be provided without increasing the type of material.

  In still another specific aspect of the piezoelectric vibration device according to the present invention, the piezoelectric vibration device has first and second piezoelectric element bonding surfaces that face each other, and each of the first and second piezoelectric element bonding surfaces has Piezoelectric elements are joined. In this case, since the piezoelectric elements are bonded to both surfaces of the support member, a large amount of displacement can be obtained and the sound pressure can be increased.

  In still another specific aspect of the piezoelectric vibration device according to the present invention, the piezoelectric body and the support member have a rectangular planar shape having a short side and a long side. The length of the rectangular short side of the support member is equal to the length of the rectangular short side of the piezoelectric body. The first and second drive electrodes are formed over the entire length in the short side direction of the piezoelectric body. In this case, the mother laminated body formed by laminating the mother piezoelectric body and the mother supporting member is separated by a distance equal to the length of the rectangular short side of the supporting member and the length of the short side of the rectangular piezoelectric body. The piezoelectric vibration device can be easily obtained by cutting with. Therefore, the mass productivity of the piezoelectric vibration device can be improved.

  In still another specific aspect of the piezoelectric vibration device according to the present invention, the first drive electrode is formed on the first main surface of the piezoelectric body, and the second drive electrode is the second main electrode of the piezoelectric body. It is formed on the entire surface. The piezoelectric element further includes a connection electrode that is formed on the first main surface of the piezoelectric body in the inactive region of the piezoelectric body and is electrically connected to the second drive electrode. The connection electrode is formed so as to extend from the first main surface of the piezoelectric body to the side surface of the piezoelectric body, and is connected to the second drive electrode at a ridge line formed by the side surface of the piezoelectric body and the second main surface. Has been. In this case, the first drive electrode can be easily joined to the second wiring electrode on the piezoelectric element joining surface of the support member without lowering the drive efficiency of the piezoelectric element.

  In still another specific aspect of the piezoelectric vibration device according to the present invention, the length of the long side of the rectangular shape of the support member is longer than the length of the long side of the rectangular shape of the piezoelectric element. The first wiring electrode reaches the side region of the joined portion. In this case, the first wiring electrode can be easily electrically connected to the outside.

  In still another specific aspect of the piezoelectric vibration device according to the present invention, the length of the long side of the rectangular support member is L1, and the length along the long side direction of the rectangular support member of the active region in the piezoelectric body is L2. (L2 / L1) × 100% is 75% or more. In this case, the piezoelectric element can be joined to the support member and the piezoelectric member can be electrically connected without reducing the amount of displacement of the piezoelectric element that vibrates in the bending mode.

  In the piezoelectric vibration device according to the present invention, the first drive electrode of the piezoelectric element is electrically connected to the first wiring electrode of the support member by the first bonding material layer, and the first bonding material layer Since the piezoelectric element is bonded to the piezoelectric element bonding surface of the support member, the piezoelectric element is firmly bonded to the support member. Therefore, when the piezoelectric vibration device is vibrated in the bending mode, the electrical connection portion is hardly broken or the electrode is not peeled off, and the reliability of the piezoelectric vibration device can be effectively increased.

FIGS. 1A and 1B are a perspective view and an exploded perspective view for explaining a piezoelectric vibration device according to a first embodiment of the present invention. FIG. 2 shows a ratio (L2 / L1) × 100% between the length L2 of the active region of the piezoelectric element and the length L1 of the long side of the support member in the piezoelectric vibration device according to the first embodiment of the present invention. It is a figure which shows the relationship between displacement amount. FIG. 3 shows a ratio (L2 / L1) × 100% between the length L2 of the active region of the piezoelectric element and the length L1 of the long side of the support member in the piezoelectric vibration device according to the first embodiment of the present invention. It is a figure which shows the relationship between generation force. FIG. 4 is a perspective view of the piezoelectric vibration device according to the second embodiment of the present invention. FIG. 5 is an exploded perspective view of the piezoelectric vibration device according to the second embodiment of the present invention. FIG. 6 is a front sectional view showing a first modification of the piezoelectric element used in the piezoelectric vibration device of the present invention. FIG. 7 is a front sectional view showing a second modification of the piezoelectric element used in the piezoelectric vibration device of the present invention. FIG. 8 is a front sectional view showing a third modification of the piezoelectric element used in the piezoelectric vibration device of the present invention. FIG. 9 is a perspective view of a piezoelectric vibration device according to a third embodiment of the present invention. FIG. 10 is a front sectional view of a piezoelectric vibration device according to a fourth embodiment of the present invention. FIG. 11 is a schematic exploded perspective view of a vibration module provided with a plurality of piezoelectric vibration devices of the present invention. FIG. 12 is a perspective view for explaining a modification of the piezoelectric vibration device according to the first embodiment of the present invention. FIG. 13 is an exploded perspective view of the piezoelectric vibration device according to the modification shown in FIG. FIG. 14 is a perspective view for explaining a support member used in another modification of the piezoelectric vibration device according to the first embodiment of the present invention. FIG. 15 is a perspective view for explaining still another modification of the piezoelectric vibration device according to the first embodiment of the present invention. 16 is an exploded perspective view of the piezoelectric vibration device according to the modification shown in FIG. FIG. 17 is a partially enlarged cross-sectional view showing a main part of a conventional piezoelectric vibration device.

  Hereinafter, the present invention will be clarified by describing specific embodiments of the present invention with reference to the drawings.

  1A and 1B are a perspective view and an exploded perspective view of a piezoelectric vibration device 1 according to a first embodiment of the present invention. The piezoelectric vibration device 1 is a unimorph type piezoelectric vibration device. The piezoelectric vibration device 1 includes a rectangular plate-like support member 2 that functions as a vibration plate.

  In this embodiment, the support member 2 is configured by a rectangular plate-shaped substrate made of an insulating material. In this embodiment, a glass epoxy substrate is used as the substrate made of such an insulating material. The glass epoxy substrate is excellent in machinability. Therefore, as will be described later, it can be easily and accurately cut out from the mother base. Therefore, the piezoelectric vibration device 1 can be mass-produced with high accuracy.

  But the support member 2 can be comprised with the appropriate insulating material which implement | achieves a big displacement amount. Further, the support member 2 may be formed of a metal plate. In that case, if an insulating layer is provided on the upper surface of the metal plate in order to prevent a short circuit between first and second wiring electrodes described later, Good.

  The support member 2 has a rectangular plate shape, and the length direction dimension of the rectangular planar shape is L1, and the width direction dimension is W.

  The upper surface of the support member 2 is a piezoelectric element bonding surface 2a. A first wiring electrode 3 and a second wiring electrode 4 are formed on the upper surface of the support member 2. The first and second wiring electrodes 3 and 4 are electrically insulated from each other and face each other with a gap therebetween.

  A piezoelectric element 7 is bonded to the first and second wiring electrodes 3 and 4 through first and second bonding material layers 5 and 6. The first and second bonding material layers 5 and 6 are made of an appropriate conductive adhesive containing a conductive filler. However, even with an adhesive that does not contain a conductive filler, conduction can be ensured if the electrodes are in direct contact with each other. Therefore, an insulating adhesive may be used. Alternatively, if the AC electric field applied to the piezoelectric element 7 has an AC impedance value capable of transmitting electrical energy that can drive the piezoelectric element 7, the electrodes are not necessarily provided between the first and second bonding material layers 5 and 6. May not be in direct contact with each other, and may be electromagnetic coupling such as a capacitor.

  The piezoelectric element 7 has a rectangular plate-like planar shape. The width direction dimension of the piezoelectric element 7 is made equal to the width direction dimension W of the support member 2. More specifically, the piezoelectric element 7 has a rectangular plate-like piezoelectric body 8. The piezoelectric body 8 has a lower surface 8a as a first main surface and an upper surface 8b as a second main surface.

  The piezoelectric body 8 is made of lead zirconate titanate (PZT) or a lead-free piezoelectric body, for example, a piezoelectric body such as potassium sodium niobate (KNN). In the first embodiment of the present invention, the piezoelectric body 8 is made of piezoelectric ceramics. , Polarized in the thickness direction.

  A first drive electrode 9 is formed on the lower surface 8 a of the piezoelectric body 8. A second drive electrode 10 is formed on the entire upper surface 8 b of the piezoelectric body 8. A piezoelectric portion where the first drive electrode 9 and the second drive electrode 10 are opposed to each other via the piezoelectric body 8 is an active region driven by the piezoelectric effect. The portions other than the active region of the piezoelectric body 8 are inactive regions.

  In the present embodiment, since the first drive electrode 9 is not formed on the entire lower surface 8a, the piezoelectric body 8 has the active region and the inactive region.

  On the lower surface 8a, a connection electrode 10a is formed so as to face the first drive electrode 9 with a gap therebetween. The connection electrode 10a extends from the lower surface 8a of the piezoelectric body 8 through the side surface to the ridge line formed by the side surface and the upper surface 8b. The connection electrode 10 a is connected to the second drive electrode 10 at the ridgeline.

  The first and second drive electrodes 9 and 10 and the connection electrode 10a can be formed of an appropriate conductive material. That is, the first and second drive electrodes 9, 10 and the connection electrode 10a can be formed by one or more conductive layers made of Ag, Cu, Ni, Cr, Pd, or an alloy thereof.

  In the piezoelectric element 7, since the first and second drive electrodes 9 and 10 are opposed to each other via the piezoelectric body 8, an AC voltage or an arbitrary waveform voltage is applied from the first and second drive electrodes 9 and 10. By doing so, the laminated body of the piezoelectric element 7 and the supporting member 2 as a vibration plate can be vibrated in a bending mode.

  On the other hand, the first drive electrode 9 is bonded to the first wiring electrode 3 by the first bonding material layer 5. Similarly, the connection electrode 10 a is bonded to the second wiring electrode 4 by the second bonding material layer 6.

  Bonding by the first bonding material layer 5 and the second bonding material layer 6 is performed on the upper surface of the support member 2 which is the piezoelectric element bonding surface 2a. Therefore, the piezoelectric element 7 can be firmly fixed to the first and second wiring electrodes 3 and 4 by the first and second bonding material layers 5 and 6.

  Moreover, the first and second bonding material layers 5 and 6 are made of a conductive adhesive as described above. Therefore, the first drive electrode 9 can be reliably electrically connected to the first wiring electrode 3, and the connection electrode 10 a, and hence the second drive electrode 10 can be reliably electrically connected to the second wiring electrode 4. Can be connected.

  The conventional piezoelectric vibration device shown in FIG. 17 has a problem that the piezoelectric vibrators 1001 and 1002 are damaged or deformed because the electrical connection is achieved using the clamp 1005.

  On the other hand, in the present embodiment, the piezoelectric element 7 is bonded to the support member 2 by the first and second bonding material layers 5 and 6, and electrical connection is achieved. Therefore, since vibration is hardly inhibited in the piezoelectric element 7, it is difficult for the displacement amount to decrease, and good vibration characteristics can be obtained. In addition, since stress concentration due to clamping or the like is unlikely to occur, peeling of the first and second drive electrodes 9 and 10 and destruction of the piezoelectric body 8 and the support member 2 are unlikely to occur.

  Further, the first and second drive electrodes 9 and 10 can be formed with high accuracy and at low cost by a printing method.

  In addition, since it is not necessary to perform soldering or the like on the first and second drive electrodes 9 and 10 of the piezoelectric element 7, the piezoelectric element 7 can be thinned.

  Furthermore, since the support member 2 is made of an insulating material, it is difficult for leakage to occur, and it is difficult for an electric person who operates an electronic device on which the piezoelectric vibration device 1 is mounted to generate electric shock. In addition, in the conventional piezoelectric vibration device, since a diaphragm made of metal is used as a support member, it is necessary to form an insulating layer. However, in this embodiment, the support member 2 is made of an insulating material. Therefore, it is not necessary to form such an insulating layer.

  Preferably, the support member 2 includes a bending mode support portion that supports the support member 2 from the outside so that the piezoelectric element 7 vibrates in the bending mode together with the piezoelectric element 7 when the piezoelectric element 7 vibrates in the bending mode. Yes. The support structure of the support member 2 from the outside is arbitrary, such as a cantilever beam or a doubly supported beam. In any case, by supporting the supporting member 2 with the bending mode supporting portion, the supporting member 2 vibrates in the bending mode having the same frequency together with the piezoelectric element 7.

  In the present embodiment, the bending mode support portion is present in the extension portions 2b and 2c, which are peripheral portions located outside the region where the piezoelectric element 7 is bonded. The first and second wiring electrodes 3 and 4 reach the extensions 2b and 2c.

  In the present embodiment, it is preferable that at least the primary bending mode node point (node) of the supporting member 2 is located on the bending mode support portion. Thereby, it is difficult to inhibit at least the vibration in the primary bending mode.

  Next, an example of a method for manufacturing the piezoelectric vibration device 1 of the present embodiment will be described.

  When manufacturing the piezoelectric vibration device 1, a mother support member and a mother piezoelectric element are prepared. That is, a mother support member and a mother piezoelectric element in which a large number of support members 2 and piezoelectric elements 7 are assembled in a matrix are prepared. In the mother support member, the first and second wiring electrodes of the mother for forming the first and second wiring electrodes 3 and 4 are formed on the upper surface. The first and second wiring electrodes of the mother are formed by preparing a glass epoxy substrate with copper foil, patterning the copper foil, screen printing or thin film forming method on the glass epoxy substrate. It can be performed by an appropriate method such as a method of forming the second wiring electrode.

  Similarly, to obtain the mother piezoelectric element, the first and second drive electrodes of the mother are formed in the same manner on the upper and lower surfaces of the mother piezoelectric body.

  Thereafter, the mother piezoelectric element and the mother support member are bonded to each other with a conductive adhesive for forming the first and second bonding material layers 5 and 6. In this way, a mother laminate is obtained. The mother laminate is cut in the thickness direction. Thereafter, the side surface portion of the connection electrode 10 a is formed on the side surface of the piezoelectric body 8. In this way, the piezoelectric vibration device 1 can be easily mass-produced.

  That is, in the present embodiment, the width-direction dimension W, which is the dimension in the length direction of the short side of the rectangular plate-shaped support member 2, and the width-direction dimension of the piezoelectric element 7 are equalized. A large number of piezoelectric vibration devices 1 can be mass-produced easily and with high accuracy by cutting the laminate.

  The length direction dimension L1 of the support member 2 is longer than the length direction dimension of the piezoelectric element 7. As shown in FIG. 1A, the support member 2 extends so as to reach the side where the piezoelectric elements 7 are laminated on the piezoelectric element bonding surface 2 a of the support member 2. First and second wiring electrodes 3 and 4 are formed so as to reach the extending portions 2b and 2c extending to the sides. Therefore, since the extension portions 2b and 2c are supported from the outside and are electrically connected, the supported portion is not the piezoelectric element 7, and is not an active region of the piezoelectric element 7 in particular. And the stress of the vibration concentrated on the support part are added together, and the piezoelectric element 7 is not damaged or deformed such as a crack, and the local electrical connection location of the active region of the piezoelectric element 7 Thus, the first and second wiring electrodes 3 and 4 can be easily electrically connected to the external terminal without causing stress concentration. For example, a metal clip may be used as the external terminal. If the metal clip is sandwiched between the first and second wiring electrodes 3 and 4 formed in the extending portions 2b and 2c, the first and second wiring electrodes 3 and 4 are used for the first and first wiring electrodes. The two drive electrodes 9, 10 can be easily electrically connected to the external terminals. In this case, since the metal clip sandwiches and supports the extensions 2b and 2c, the problem that the piezoelectric element 7 is damaged or deformed due to the stress concentration of vibration caused by the metal clip is improved. The problem of peeling of the drive electrode and the wiring electrode due to the difference in rigidity of the drive electrode of the vibrator is improved.

  The dimension of the active region in the piezoelectric element 7 in the length direction is L2. That is, the dimension in the long side direction of the rectangle of the active region where the first and second drive electrodes 9 and 10 are opposed is L2.

  The ratio (L2 / L1) × 100 (%) of the lengthwise dimension L2 of the active region to the lengthwise dimension L1 of the support member 2 is variously changed to produce a large number of piezoelectric vibrators 1 of the above embodiments. The amount of displacement and the generated force were measured.

  Here, both end portions of the support member 2 are sandwiched by edge-shaped members in the thickness direction so that the distances between the two extension portions 2b and 2c from the end surface of the support member 2 to the end surface of the piezoelectric element 7 are equal. By fixing the piezoelectric element 7 to the central portion of the support member 2, the portion is restrained from being displaced in the thickness direction, the interval between the members is set to L 1, and a predetermined voltage (200 V) is applied The amount of displacement in the thickness direction of the central portion was measured with a laser displacement meter, and the value was taken as the amount of displacement. The generated force is the same voltage as when the displacement is measured, and the edge is pressed in the thickness direction of the support member so that the displacement is zero. This is a value obtained by measuring with a gauge. In this measurement, as an example of the embodiment, L2 is 50 mm, W is 5 mm, and the thickness is 50 mm, W is 5 mm, and the support member 2 is made of a glass epoxy substrate with a copper foil having a rectangular shape of L1 of 53 mm, W of 5 mm, and thickness of 0.2 mm. A piezoelectric vibration device 1 in which a piezoelectric element 7 having first and second drive electrodes 9 and 10 formed by a sputtering method on a piezoelectric body 8 made of rectangular PZT having a thickness of 0.2 mm was used.

  The results are shown in FIGS.

  2 and 3 are relative values, and the case where (L2 / L1) × 100 (%) is 100% was determined as 100%.

  As is apparent from FIGS. 2 and 3, if (L2 / L1) × 100 (%) is 75% or more, the displacement amount and the generated force can be sufficiently increased to 90% or more, and 75% It can be seen that the amount of displacement and the value of the generated force are more stable against fluctuations in the ratio of L2 / L1. Therefore, even if the ratio of the lengthwise dimension L1 of the support member 2 to the lengthwise dimension L2 of the active region varies due to variations in the manufacturing process of the piezoelectric vibration device 1, the displacement amount and the generated force value are sufficiently large. Since (L2 / L1) × 100 (%) is preferably 75% or more, since it has an effect of stabilizing with the value.

  4 and 5 are a perspective view and an exploded perspective view of the piezoelectric vibration device 21 according to the second embodiment of the present invention.

  In the piezoelectric vibration device 21 of the second embodiment, the lower surface 2d of the support member 2 is also a piezoelectric element bonding surface, and the piezoelectric element 7 is also connected to the first and second bonding material layers 5 and 6 on the lower surface 2d. It is the same as that of 1st Embodiment except having laminated | stacked via. Therefore, about the same part, the description in 1st Embodiment shall be used by attaching | subjecting the same reference number.

  In the piezoelectric vibration device 21 of the second embodiment, the piezoelectric elements 7 and 7 are laminated on both surfaces of the support member 2, so that not only the same effect as the first embodiment can be obtained, but also the first Compared to the piezoelectric vibration device 1 of the embodiment, a large displacement amount and a large sound pressure can be obtained. Thus, in the present invention, both surfaces of the support member may be piezoelectric element bonding surfaces.

  In addition, two or more piezoelectric elements 7 may be laminated on one piezoelectric element bonding surface.

  The piezoelectric element used in the piezoelectric vibration device of the present invention is not limited to the piezoelectric element 7.

  FIG. 6 shows a first modification of the piezoelectric element used in the piezoelectric vibration device of the present invention. The stacked piezoelectric element 31 has a piezoelectric body 32. The piezoelectric body 32 has first and second main surfaces 32a and 32b facing each other. The piezoelectric body 32 has a plurality of piezoelectric layers. A first drive electrode 33 is formed on the first main surface 32a of the piezoelectric body 32, and a second drive electrode 34 is formed on the second main surface 32b. Further, a plurality of first internal drive electrodes 35 that are commonly connected to the first drive electrode 33 and the end face of the piezoelectric body 32 are formed in the piezoelectric body 32. A plurality of second internal drive electrodes 36 are formed so as to overlap the first drive electrode 33 or the first internal drive electrode 35 via the piezoelectric layer. The plurality of second internal drive electrodes 36 are commonly connected to the second drive electrode 34 at the end face of the piezoelectric body 32. Thus, in the present invention, the laminated piezoelectric element 31 having a plurality of internal drive electrodes may be used.

  By using the laminated piezoelectric element 31, a large displacement can be obtained with a low driving voltage. That is, the displacement due to the piezoelectric effect is proportional to the applied electric field strength. In the multilayer piezoelectric element 31, the thickness of the piezoelectric layer between the drive electrodes connected to different potentials can be reduced, so that a large displacement can be obtained with a lower voltage.

  FIG. 7 shows a second modification of the piezoelectric element used in the piezoelectric vibration device of the present invention. The piezoelectric element 41 shown in FIG. The piezoelectric body 42 has first and second main surfaces 42a and 42b that face each other. The piezoelectric body 42 has a plurality of piezoelectric layers. First and second drive electrodes 43 and 44 are formed in the piezoelectric body 42 so as to face each other through the piezoelectric layer. The first drive electrode 43 is formed in parallel with the first main surface 42 a on the first main surface 42 a side of the piezoelectric body 42. Similarly, the second drive electrode 44 is formed on the second main surface 42b side of the piezoelectric body 42 in parallel with the second main surface 42b. That is, in the present invention, the first and second drive electrodes may not be directly formed on the first and second main surfaces of the piezoelectric body. Inactive layers 42 c and 42 d are formed outside the first and second drive electrodes 43 and 44. As described above, the piezoelectric element 41 having the inactive layers 42c and 42d may be used.

  In the piezoelectric element 41 shown in FIG. 7, since the inactive layers 42 c and 42 d are provided, it is possible to suppress the clamping of the active region inside the piezoelectric body 42. In the piezoelectric element 41, the first and second drive electrodes 43 and 44 are covered with the inactive layers 42c and 42d, so that they are not easily exposed to external moisture. Therefore, the product life can be extended. In addition, it is difficult for electric leakage to occur, and it is also possible to prevent electric shock of a human who operates an electronic device equipped with the piezoelectric vibration device.

  Furthermore, FIG. 8 shows a third modification of the piezoelectric element used in the piezoelectric vibration device of the present invention. A stacked piezoelectric element 51 shown in FIG. 8 has a piezoelectric body 52. The piezoelectric body 52 has first and second main surfaces 52a and 52b facing each other. The piezoelectric body 52 has a plurality of piezoelectric layers. First and second drive electrodes 53 and 54 are formed in the piezoelectric body 52 so as to face each other through the piezoelectric layer. The first drive electrode 53 is formed on the first main surface 52a side of the piezoelectric body 52 in parallel with the first main surface 52a. Similarly, the second drive electrode 54 is formed on the second main surface 52b side of the piezoelectric body 52 in parallel with the second main surface 52b. The multilayer piezoelectric element 51 has inactive layers 52c and 52d on the first and second main surfaces 52a and 52b side of the piezoelectric body 52, like the piezoelectric element 41 shown in FIG. A plurality of internal drive electrodes 55 are formed between the first and second drive electrodes 53 and 54.

  As shown in FIGS. 6 to 8, the piezoelectric element used in the piezoelectric vibration device of the present invention may have an inactive layer outside the first drive electrode and the second drive electrode. A laminated piezoelectric element in which another drive electrode is formed between the first and second drive electrodes may be used.

  FIG. 9 is a perspective view of a piezoelectric vibration device according to a third embodiment of the present invention. In the piezoelectric vibration device 61 according to the third embodiment, a protective layer 62 made of an insulating material is formed on the piezoelectric element 7. In other respects, the piezoelectric vibration device 61 is the same as the piezoelectric vibration device 1 of the first embodiment. Accordingly, the description of the piezoelectric vibration device 1 is incorporated by giving the same reference numerals to the same portions.

  The protective layer 62 is made of an insulating material and is provided so as to cover the entire upper surface of the second drive electrode 10. Therefore, it is possible to prevent electric shock from being generated by the human second drive electrode 10 who operates the electronic device on which the piezoelectric vibration device is mounted. The insulating material constituting the protective layer 62 is not particularly limited, and synthetic resin, insulating ceramics, or the like can be used. However, in order not to suppress the displacement of the piezoelectric element 7, it is desirable to use an insulating material having excellent elasticity.

  However, the protective layer 62 may be formed of the same piezoelectric material as that of the piezoelectric body 8. In that case, the protective layer 62 can be formed without increasing the type of material for forming the piezoelectric vibration device 61 and without causing a complicated manufacturing process.

  FIG. 10 is a front sectional view showing a piezoelectric vibration device according to a fourth embodiment of the present invention. In the piezoelectric vibration device 71 of the fourth embodiment, a protective layer 72 is formed on the lower surface side of the piezoelectric element 7 instead of the protective layer 62 of the third embodiment. The protective layer 72 is made of an insulating bonding material. In addition, the piezoelectric vibration device 71 includes the first and second bonding material layers 5A, 5A, which are formed thicker than the first and second bonding material layers 5 and 6 due to the formation of the protective layer 72. 6A.

  Therefore, as shown in FIG. 10, the piezoelectric element 7 is bonded to the piezoelectric element bonding surface 2 a of the support member 2 by the protective layer 72. Therefore, the area of the first bonding material layer 5A is reduced. Thus, when the protective layer 72 is provided, the piezoelectric element 7 can be firmly bonded to the support member 2 even if the area of the first bonding material layer 5A is reduced.

  When the protective layer 72 is provided, by using an insulating adhesive having excellent moisture resistance as the protective layer 72, it is possible to suppress deterioration of characteristics due to the ingress of moisture from the lower surface side of the piezoelectric element 7. When a member that can electrically insulate the first drive electrode 9 and the connection electrode 10a, such as an insulating adhesive or an anisotropic conductive adhesive, is used as the protective layer 72, the support member 2 and the piezoelectric element are used. The protective layer 72 may be disposed between the 7 and the gap 7.

  Note that both the protective layer 62 shown in FIG. 9 and the protective layer 72 shown in FIG. 10 may be formed. In that case, protection can be achieved by the protective layers 62 and 72 on either the upper surface or the lower surface of the piezoelectric element 7.

  The piezoelectric vibration device according to the present invention can be used as a piezoelectric sounding body such as various piezoelectric actuators and piezoelectric speakers. In recent years, touch panel type input devices have been widely used as a kind of input device for portable electronic devices. In this touch panel type input device, a device called “Haptics” in which a reaction force against an input by a human gives a click feeling has attracted attention. The piezoelectric vibration device of the present invention can be suitably used as an actuator that applies a reaction force in such haptics.

  FIG. 12 is a perspective view for explaining a piezoelectric vibration device 1A which is a modified example of the piezoelectric vibration device 1 of the first embodiment, and FIG. 13 is an exploded perspective view thereof. The piezoelectric vibration device 1 </ b> A according to this modification includes a support member 2 </ b> A instead of the support member 2 of the first embodiment. In this modification, the same piezoelectric element 7 as in the first embodiment is used. However, the width of the support member 2 </ b> A is wider than the width of the piezoelectric element 7. As shown in FIG. 13, the first wiring electrode 3A and the second wiring electrode 4A are formed on the upper surface of the support member 2A. The first and second wiring electrodes 3A and 4A are electrically insulated from each other and face each other with a gap therebetween. The piezoelectric element 7 is bonded to the first and second wiring electrodes 3A and 4A via the first and second bonding material layers 5 and 6. 3 A of 1st wiring electrodes have the junction part 3a, the terminal part 3b, and the connection part 3c. A first bonding material layer 5 is laminated on the bonding portion 3a. The joint portion 3a reaches the full width in the width direction of the support member 2A. The terminal portion 3b is provided on the second wiring electrode 4A side. The terminal portion 3b is opposed to the second wiring electrode 4A with a gap in the width direction of the support member 2A. The terminal portion 3b is formed close to one end side of the support member 2A, similarly to the second wiring electrode 4A. The joint part 3a and the terminal part 3b are connected by the connection part 3c. Then, the terminal portion 3b and the second wiring electrode 4A are exposed on one end side of the support member 2A as shown in FIG. Therefore, electrical connection with the outside can be easily performed.

  FIG. 14 is a perspective view for explaining a support member 2B used in another modification of the piezoelectric vibration device according to the first embodiment of the present invention. In the piezoelectric vibration device 1 </ b> A shown in FIG. 13, the width of the support member 2 </ b> A is wider than the width of the piezoelectric element 7 in order to prevent a short circuit between the terminal portion 3 b and the second wiring electrode 4 </ b> A. However, as shown in FIG. 14, it is possible to use a support member 2 </ b> B having the first wiring electrode 3 </ b> B and having the same width as the width of the piezoelectric element 7. In this case, the first wiring electrode 3B includes a joint portion 3d, a terminal portion 3e, and a connecting portion 3f. A first bonding material layer 5 is laminated on the bonding portion 3d. The joint portion 3d reaches the full width in the width direction of the support member 2B. The terminal portion 3e is provided on the second wiring electrode 4A side. The terminal portion 3e is opposed to the second wiring electrode 4A with a gap in the width direction of the support member 2B. The terminal portion 3e is formed close to one end side of the support member 2A, similarly to the second wiring electrode 4A. The joint portion 3d and the terminal portion 3e are connected by a connecting portion 3e that extends from one end surface of the support member 2B to the other end surface through the lower surface.

  Note that the entire width of the support member 2 </ b> B shown in FIG. 14 may be larger than the width of the piezoelectric element 7.

  FIG. 15 is a perspective view for explaining a piezoelectric vibration device 1B which is a modification of the piezoelectric vibration device 1 of the first embodiment, and FIG. 16 is an exploded perspective view thereof. The piezoelectric vibration device 1B is formed by laminating the laminated piezoelectric element 51 shown in FIG. 8 on the support member 2A. The support member 2A is substantially the same as the support member 2A shown in FIG. Of course, the width of the support member 2A is the same as the width of the multilayer piezoelectric element 51, but the support member 2A having a width wider than that of the multilayer piezoelectric element 51 may be used as in the case of FIG. Good.

  Also in the modification shown in FIGS. 15 and 16, the terminal portion 3b of the first wiring electrode 3A is provided close to the second wiring electrode 4A and one end side in the length direction of the support member 2A. Therefore, electrical connection with the outside can be easily performed on one end side in the length direction of the support member 2A. In addition, as shown in FIG. 15, since the terminal portion 3b and the second wiring electrode 4A are exposed on one end side of the support member 2A, connection to the outside can be more easily performed.

  FIG. 11 is a schematic exploded perspective view of a vibration module 81 using the piezoelectric vibration device of the present invention. In the vibration module 81, the plurality of piezoelectric vibration devices 1, 1 of the first embodiment are mounted on the upper surface of the substrate 82 by bonding material layers 83 and 84. And the flexible board | substrate 85 used with a touchscreen type input device is arrange | positioned above the some piezoelectric vibration apparatus 1 and 1. As shown in FIG. Such a vibration module can be suitably used for Haptics.

  In the piezoelectric vibration device 1 of the above embodiment, a rectangular plate-shaped piezoelectric body is used, but the piezoelectric body of the piezoelectric vibration device of the present invention has a shape other than the rectangular plate shape, for example, a disk shape. There may be. Similarly, the support member is not limited to the rectangular plate shape as long as it functions as the diaphragm of the unimorph vibration device, and may have a disk shape or the like.

DESCRIPTION OF SYMBOLS 1,1A, 1B ... Piezoelectric vibration device 2, 2A, 2B ... Support member 2a ... Piezoelectric element joint surface 2b, 2c ... Extension part 2d ... Bottom surface 3, 3A, 3B ... First wiring electrode 3a ... Joint part 3b ... Terminal Portion 3c: Connecting portion 3d: Bonding portion 3e: Terminal portion 3f: Connecting portion 4, 4A ... Second wiring electrode 5 ... First bonding material layer 5A ... First bonding material layer 6 ... Second bonding material layer DESCRIPTION OF SYMBOLS 7 ... Piezoelectric element 8 ... Piezoelectric body 8a ... 1st main surface 8b ... 2nd main surface 9 ... 1st drive electrode 10 ... 2nd drive electrode 10a ... Connection electrode 21 ... Piezoelectric vibration apparatus 31 ... Piezoelectric element 32 ... Piezoelectric body 32a ... first main surface 32b ... second main surface 33 ... first drive electrode 34 ... second drive electrode 35 ... first internal drive electrode 36 ... second internal drive electrode 41 ... piezoelectric Element 42 ... Piezoelectric body 42a ... First main surface 42b ... Second main surface 42c, 42d ... Inactive DESCRIPTION OF SYMBOLS 43 ... 1st drive electrode 44 ... 2nd drive electrode 51 ... Piezoelectric element 52 ... Piezoelectric body 52a ... 1st main surface 52b ... 2nd main surface 52c, 52d ... Inactive layer 53 ... 1st drive electrode 54 ... second drive electrode 55 ... internal drive electrode 61 ... piezoelectric vibration device 62 ... protective layer 71 ... piezoelectric vibration device 72 ... protective layer 81 ... vibration module 82 ... substrate 83,84 ... bonding material layer 85 ... flexible substrate

Claims (11)

A piezoelectric body having first and second main surfaces facing each other;
A first drive electrode formed in parallel to the first main surface on the first main surface side of the piezoelectric body;
A second drive electrode which is formed in parallel to the second main surface on the second main surface side of the piezoelectric body and faces the first drive electrode; The region where the second drive electrode is opposed to the piezoelectric body in the thickness direction is the active region, and the region where the first drive electrode is not opposed to the second drive electrode is inactive. A piezoelectric element that is an area;
A support member having a piezoelectric element bonding surface to which the piezoelectric element is bonded;
The support member has a first wiring electrode formed on the piezoelectric element bonding surface and electrically connected to the first drive electrode of the piezoelectric element,
The first drive electrode of the piezoelectric element is electrically connected to the first wiring electrode of the support member, and the first main surface of the piezoelectric element is used as a piezoelectric element bonding surface of the support member. further example Bei the first bonding material layer are joined,
The support member has a bending mode support portion for supporting the support member from the outside so that when the piezoelectric element vibrates in the bending mode, the piezoelectric element vibrates in the bending mode of the same frequency. The mode support portion is located in a peripheral portion located outside a region where the piezoelectric element is bonded, and the first wiring electrode reaches the peripheral portion . The piezoelectric element is formed on the first main surface of the piezoelectric body in the inactive region of the piezoelectric body, and is electrically connected to the second drive electrode formed on the second main surface. A connection electrode that is
The support member further includes a second wiring electrode formed on the piezoelectric element bonding surface and electrically connected to the second drive electrode;
A second bonding material layer electrically connecting the connection electrode and the second wiring electrode and bonding the first main surface of the piezoelectric element to the piezoelectric element bonding surface of the support member; The piezoelectric vibration device according to claim 1, further comprising: 3. The piezoelectric vibration device according to claim 1, wherein at least a primary bending mode node of the supporting member is located in the bending mode support portion. The piezoelectric element is formed on the first main surface of the piezoelectric body and further includes a protective layer made of an insulating material, and the protective layer is bonded to the piezoelectric element bonding surface of the support member. The piezoelectric vibration device according to any one of claims 1 to 3 . Said piezoelectric element, said being formed on a second main surface of the second of said piezoelectric body so as to cover the drive electrodes, and further has a protective layer made of an insulating material, claim 1-4 The piezoelectric vibration device according to item 1. The protective layer is made of the same material as the piezoelectric body, the piezoelectric vibration device according to claim 4 or 5. First the support member facing each other, a second piezoelectric element joining surface, the first, each of the second piezoelectric element joint surface, wherein the piezoelectric element is bonded, according to claim 1 to 6 The piezoelectric vibration device according to any one of claims. The piezoelectric body and the support member have a rectangular planar shape having a short side and a long side, and the length of the rectangular short side of the support member is equal to the length of the rectangular short side of the piezoelectric body. And
Said first, second driving electrodes, the formed across the short side direction entire length of the piezoelectric body, the piezoelectric vibration device according to any one of claims 1-7. The first drive electrode is formed on the first main surface of the piezoelectric body;
The second drive electrode is formed on the entire second main surface of the piezoelectric body;
The piezoelectric element further includes a connection electrode formed on the first main surface of the piezoelectric body in the inactive region of the piezoelectric body and electrically connected to the second drive electrode. And
The connection electrode is formed so as to extend from the first main surface of the piezoelectric body to the side surface of the piezoelectric body, and in the ridge line formed between the side surface of the piezoelectric body and the second main surface, The piezoelectric vibration device according to claim 8 , wherein the piezoelectric vibration device is connected to the drive electrode. The length of the long side of the rectangular shape of the support member is longer than the length of the long side of the rectangular shape of the piezoelectric element, and a side region of the portion where the piezoelectric element of the support member is joined. The piezoelectric vibration device according to claim 9 , wherein the first wiring electrode reaches. When the length of the long side of the rectangle of the support member is L1, and the length of the active region in the piezoelectric body along the long side direction of the rectangle of the support member is L2, (L2 / L1) × The piezoelectric vibration device according to claim 10 , wherein 100% is 75% or more.

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