JP2006304589A - Piezoelectric actuator, liquid transfer system, method of manufacturing piezoelectric actuator, and method of manufacturing liquid transfer system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To restrain fused conductive material from flowing out to its surroundings when joining the electrode on the surface of a piezoelectric layer with wiring material by conductive material. <P>SOLUTION: Individual cooling passages 47 are made in a section, which faces the wiring part 35 between each individual electrode 32 and a contact 35a, of a cavity plate 10. Therefore, the fused conductive material 45 can be cooled with coolant 60 within the individual passages 47 by fusing the conductive material 45 between the contact 35a of the wiring part 35 and the terminal 42a of an FPC 40 while letting the coolant 60 flow into these individual cooling passages 47 when joining the wiring parts 35 with the FPC40. Therefore, it can restrain the conductive material 45 from flowing out from the contact 35a to its surroundings. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a piezoelectric actuator, a liquid transfer device including the piezoelectric actuator, and a method for manufacturing the piezoelectric actuator and the liquid transfer device.

  Conventionally, piezoelectric actuators that drive an object using deformation of a piezoelectric material when an electric field is applied have been widely used in various fields. For example, Patent Document 1 (US Pat. No. 6,891,314 B2) describes an ink jet head including a piezoelectric actuator that applies discharge pressure to ink. This piezoelectric actuator includes a metal substrate supported by a rigid body, a plurality of piezoelectric elements (piezoelectric layers) disposed on the substrate, signal electrodes formed on both upper and lower surfaces of the plurality of piezoelectric elements, and a common Electrode. The signal electrode is drawn from the deformation region (actuator area) where the substrate is not bonded to the rigid body to the bonding region (area for electrical bonding) where the substrate is bonded to the rigid body. A flexible printed wiring board (FPC) made of a flexible resin base material is electrically connected. Then, a drive signal is supplied to the signal electrode via the FPC.

  Here, a plurality of terminal portions respectively corresponding to the plurality of signal electrodes are formed on the surface of the FPC on the piezoelectric element side. Further, each terminal portion is formed with a hemispherical bump made of a core material and a conductive bonding material covering the surface of the core material. Then, when connecting the FPC to the plurality of signal electrodes, the bonding material is melted by heating the bumps in a state where the portions drawn to the bonding region of the signal electrodes and the bumps of the FPC are aligned, The signal electrode and the terminal portion of the FPC are bonded by the molten bonding material.

USP 6,891,314B2 (corresponding to Japanese Patent Laid-Open No. 2003-69103 (FIGS. 1 to 3))

  By the way, in the piezoelectric actuator described in Patent Document 1, when the bonding material is melted to bond the signal electrode and the terminal portion of the FPC, a part of the molten bonding material flows out to the periphery. At this time, if the bonding material flows through the signal electrode to the deformation region, the bonding material inhibits the deformation of the piezoelectric element in the deformation region, and the piezoelectric actuator does not operate normally. Further, there is a possibility that the molten conductive bonding material flows out to another adjacent signal electrode and a short circuit occurs between the two signal electrodes.

  An object of the present invention is to suppress the molten conductive material from flowing out to the periphery when the electrode on the surface of the piezoelectric layer and the wiring member are joined together by the conductive material.

Means for Solving the Problems and Effects of the Invention

  According to the first aspect of the present invention, the diaphragm, a support member having a deformation relief part for escaping deformation of the diaphragm, and a joint part joined to the diaphragm, and opposite to the support member of the diaphragm The piezoelectric layer disposed on the side, the first electrode disposed on the surface of the piezoelectric layer on the vibration plate side, and the deformation relief portion on the surface of the piezoelectric layer on the opposite side to the vibration plate A second electrode disposed in a region; a wiring portion extending from the second electrode to a region facing the joint portion on a surface of the piezoelectric layer opposite to the diaphragm; and a conductive material at a contact of the wiring portion A wiring member for supplying a driving voltage to the second electrode, and at least one of the diaphragm and the joint, between the second electrode and the contact point. A piezoelectric actuator provided with a hollow portion in a portion facing the wiring portion of It is subjected.

  In the piezoelectric actuator of the present invention, the hollow portion may be a hole through which a coolant flows when the wiring portion and the terminal portion are joined by the conductive material, and the coolant is a liquid or a gas. Also good.

  According to the first aspect of the present invention, in this piezoelectric actuator, when a drive voltage is supplied to the second electrode via the wiring member, the deformation actuator is opposed to the deformation relief portion between the first electrode and the second electrode. An electric field acts on the portion of the piezoelectric layer that performs. Then, the portion of the piezoelectric layer to which the electric field is applied is deformed, and further, the portion facing the deformation relief portion of the diaphragm is deformed along with the deformation of the piezoelectric layer to drive the object. By the way, the contact point of the wiring part connected to the second electrode and the terminal part of the wiring member are joined by a conductive material. When the conductive material is melted during the joining, There is a possibility that a part of the conductive material flows out from the contact point through the wiring portion to the surface of the second electrode. However, in the present invention, a cavity is provided in a portion facing at least one of the diaphragm and the joint, which is the wiring portion between the second electrode and the contact. Therefore, the conductive material that flows out from the contact toward the second electrode is cooled by a cavity or a coolant such as a cooling liquid filled in the cavity, and the viscosity of the conductive material is reduced in the middle of the wiring portion. Ascending, solidification begins and no longer flows. Therefore, it is possible to prevent the conductive material from adhering to the surface of the second electrode and inhibiting the deformation of the piezoelectric layer. In the present invention, not only the mode in which the diaphragm and the first electrode are formed of separate members, but also the diaphragm has conductivity, and the surface opposite to the deformation relief portion of the diaphragm is the first. The aspect which serves as an electrode is also included.

  In the piezoelectric actuator of the present invention, the deformation relief portion includes a plurality of relief portions, a plurality of the relief portions arranged adjacent to each other along a plane, and a plurality of second electrodes respectively corresponding to the plurality of the relief portions. The plurality of cavities may be provided corresponding to the plurality of second electrodes, respectively, and the plurality of cavities may communicate with each other. In this way, when the plurality of cavities communicate with each other, a coolant such as a cooling liquid easily flows between the plurality of cavities, so that the molten conductive material can be cooled more effectively. it can.

  In the piezoelectric actuator according to the aspect of the invention, each of the hollow portions may extend to a region facing between the contacts of the two wiring portions respectively corresponding to the two adjacent second electrodes. In this configuration, the conductive material flowing out from the contact of a certain wiring portion toward the contact of the adjacent wiring portion is cooled by a coolant such as a cooling liquid in a cavity formed in a region between these two contacts. Therefore, it is possible to reliably prevent a short circuit from occurring between the two wiring portions.

  In the piezoelectric actuator of the present invention, the hollow portion may be formed in an annular shape surrounding a contact point of the wiring portion. Therefore, it is possible to more reliably prevent the molten conductive material from flowing out from the contact to the periphery thereof.

  In the piezoelectric actuator of the present invention, the wiring portion may be partially narrowed between the second electrode and the contact. In this configuration, since the amount of the conductive material that flows from the contact point toward the second electrode through the wiring portion is reduced, it is possible to more reliably prevent the conductive material from adhering to the surface of the second electrode.

  According to the second aspect of the present invention, the vibration plate, a plurality of escape portions that escape deformation of the vibration plate, and a support member that is joined to the vibration plate, the support member of the vibration plate, A piezoelectric layer disposed on the opposite side; a first electrode disposed on a surface of the piezoelectric layer on the diaphragm side; and the plurality of relief portions on a surface of the piezoelectric layer opposite to the diaphragm. A plurality of second electrodes respectively disposed in opposing regions; and a plurality of wiring portions respectively extending from the plurality of second electrodes to a region facing the joint portion on the surface of the piezoelectric layer opposite to the diaphragm. A wiring member that has a plurality of terminal portions bonded to the contacts of the plurality of wiring portions through conductive materials, respectively, and that supplies a driving voltage to the plurality of second electrodes, and the diaphragm and the bonding Corresponding to at least one of the two adjacent second electrodes, respectively. Piezoelectric actuator cavity in a portion facing the portion between the contacts of two of the wiring portion is provided is provided.

  In the piezoelectric actuator of the present invention, each of the hollow portions may be a hole through which a coolant flows when the wiring portion and the terminal portion are joined by the conductive material, and the coolant is a liquid or a gas. May be.

  According to the second aspect of the present invention, the conductive material that flows out from the contact of a certain wiring part toward the contact of the adjacent wiring part is formed in a cavity formed in a region between these two contacts or, for example, a cavity Since it is cooled by a refrigerant such as a cooling liquid in the section, it is possible to reliably prevent a short circuit from occurring between the two wiring sections. In the present invention, the diaphragm includes conductivity, and the surface of the diaphragm opposite to the pressure chamber also serves as the first electrode.

  According to the third aspect of the present invention, a liquid flow path including a plurality of pressure chambers arranged along a plane, and a piezoelectric actuator that applies pressure to the liquid in the pressure chamber by changing the volume of the pressure chamber. The piezoelectric actuator includes a pressure chamber plate in which the plurality of pressure chambers are formed, and a vibration that is joined at a joint portion between the pressure chamber plates and covers the plurality of pressure chambers. A plate, a piezoelectric layer disposed on the vibration plate opposite to the pressure chamber plate, a common electrode formed on the surface of the piezoelectric layer on the vibration plate side, and the piezoelectric layer opposite to the vibration plate A plurality of individual electrodes respectively disposed in regions facing the plurality of pressure chambers on the side surface, and from the individual electrode to a region facing the bonding portion on the surface of the piezoelectric layer opposite to the diaphragm. Multiple each extending The diaphragm comprising: a wiring portion; and a wiring member having a plurality of terminal portions bonded to the contact points of the plurality of wiring portions via conductive materials, respectively, and supplying a driving voltage to the plurality of individual electrodes. There is provided a liquid transfer device in which a cavity is provided in each part of at least one of the joints facing the wiring part between the individual electrode and the contact.

  In the liquid transfer device of the present invention, the hollow portion may be a hole through which a coolant flows when the wiring portion and the terminal portion are joined by the conductive material, and the coolant is a liquid or a gas. May be.

  According to the third aspect of the present invention, when the driving voltage is selectively supplied to the plurality of individual electrodes via the wiring member, the portion of the piezoelectric layer between the individual electrode to which the voltage is applied and the common electrode The piezoelectric layer is deformed by the action of the electric field, and the diaphragm is deformed along with the deformation, and pressure is applied to the liquid in the pressure chamber. Here, when this conductive material is melted in order to join the contact of the wiring part connected to the individual electrode and the terminal part of the wiring member with the conductive material, a part of the molten conductive material is Flows from the contact point toward the individual electrode. However, since this conductive material is cooled by the cavity or by a coolant such as a cooling liquid filled in the cavity, the conductive material adheres to the surface of the individual electrode and deforms the piezoelectric layer. Inhibiting can be prevented. In addition, this invention includes the aspect in which a diaphragm has electroconductivity and the surface on the opposite side to the pressure chamber of this diaphragm serves also as a common electrode.

  According to the fourth aspect of the present invention, the filling step of filling the cavity with a cooling liquid, the conductive material is heated and melted, and the wiring portion and the terminal portion are formed by the molten conductive material. There is provided a method of manufacturing a piezoelectric actuator including a bonding step of bonding. The conductive material melted in the joining process flows out from the contact toward the second electrode through the wiring part, but this conductive material is cooled by the cooling liquid filled in the cavity part in the middle of the wiring part, Since it no longer flows, it is possible to prevent the conductive material from adhering to the second electrode.

  In the method for manufacturing a piezoelectric actuator of the present invention, the cooling liquid may include water as a main component. As described above, since the cooling liquid is mainly composed of water having a low specific heat and a high specific heat, the molten conductive material can be effectively cooled while keeping the manufacturing cost low.

  In the piezoelectric actuator manufacturing method of the present invention, the cooling liquid filled in the cavity may be forced to flow in the filling step. Thus, the cooling effect of the conductive material by the cooling liquid can be further enhanced by forcibly flowing the cooling liquid.

  According to the fifth aspect of the present invention, a flow path unit including a plurality of pressure chambers arranged along a plane, a diaphragm that is joined at a joint portion of the flow path unit and covers the plurality of pressure chambers, A piezoelectric layer disposed on the vibration plate opposite to the pressure chamber; a common electrode disposed on the vibration layer side surface of the piezoelectric layer; and a surface of the piezoelectric layer opposite to the vibration plate A plurality of individual electrodes respectively disposed in regions facing the plurality of pressure chambers, and a plurality of individual electrodes extending from the individual electrode to a region facing the bonding portion on the surface of the piezoelectric layer opposite to the diaphragm. A piezoelectric actuator having a wiring member and a wiring member including a plurality of terminal portions respectively joined to the plurality of wiring portions, and a refrigerant flow path provided in the flow path unit or the piezoelectric actuator and through which a refrigerant flows. Liquid provided A method of manufacturing a feeding device, the filling step of filling the refrigerant into the refrigerant flow path, the conductive material disposed between the wiring portion and the terminal portion, heated, and melted. There is provided a method of manufacturing a liquid transfer device including a joining step of joining the wiring portion and the terminal portion with a material.

  In the method for manufacturing a liquid transfer device of the present invention, the refrigerant channel may be a channel including the pressure chamber, and the refrigerant may be a liquid.

  According to the fifth aspect of the present invention, a part of the conductive material melted in the joining process flows out from the contact point toward the individual electrode through the wiring portion, and this conductive material is placed in the coolant channel. Cooled by the filled refrigerant, for example, a cooling liquid, the viscosity of the conductive material rises in the middle of the wiring part and does not flow any more, so that the conductive material can be prevented from adhering to the individual electrodes. . Further, when the joining process is performed by filling the flow path through which the liquid to be transferred is filled, there is no need to separately form a space for filling the cooling liquid, which is advantageous in terms of manufacturing cost. is there. In addition, the liquid transfer apparatus manufactured by the manufacturing method of the present invention includes a mode in which the diaphragm has conductivity, and the surface of the diaphragm opposite to the pressure chamber also serves as a common electrode.

  A first embodiment of the present invention will be described. This first embodiment is an example in which the present invention is applied to an inkjet head that ejects ink from nozzles onto recording paper as a liquid transfer device.

  First, the ink jet printer 100 including the ink jet head 1 will be briefly described. As shown in FIG. 1, an inkjet printer 100 includes a carriage 101 that can move in the left-right direction in FIG. 1, a serial inkjet head 1 that is provided on the carriage 101 and that ejects ink onto a recording paper P, A conveyance roller 102 that conveys the recording paper P forward in FIG. 1 is provided. The ink-jet head 1 moves in the left-right direction (scanning direction) integrally with the carriage 101, and ink is applied to the recording paper P from the emission port of the nozzle 20 (see FIG. 4) formed on the lower ink discharge surface. Inject. Then, the recording paper P recorded by the inkjet head 1 is discharged forward (paper feeding direction) by the transport roller 102.

  Next, the inkjet head 1 will be described in detail with reference to FIGS. As shown in FIGS. 2 to 5, the inkjet head 1 is disposed on the upper surface of the flow path unit 2 in which a plurality of individual ink flow paths 21 including the pressure chambers 14 (see FIG. 4) are formed. The piezoelectric actuator 3 is provided.

  First, the flow path unit 2 will be described. As shown in FIGS. 4 and 5, the flow path unit 2 includes a cavity plate 10, a base plate 11, a manifold plate 12, and a nozzle plate 13, and these four plates 10 to 13 are joined in a stacked state. Yes. Among these, the cavity plate 10, the base plate 11 and the manifold plate 12 are stainless steel plates, and ink flow paths such as a manifold 17 and a pressure chamber 14 described later can be easily etched in these three plates 10-12. Can be formed. The nozzle plate 13 is formed of a polymer synthetic resin material such as polyimide, and is bonded to the lower surface of the manifold plate 12. Or this nozzle plate 13 may be formed with metal materials, such as stainless steel, similarly to the three plates 10-12.

  As shown in FIGS. 2 to 5, the cavity plate 10 (pressure chamber plate) is formed with a plurality of pressure chambers 14 arranged adjacent to each other along a plane, and the plurality of pressure chambers 14 includes a girder 10a. It is divided by. The plurality of pressure chambers 14 are opened upward. Further, the plurality of pressure chambers 14 are arranged in two rows in the paper feeding direction (vertical direction in FIG. 2). Each pressure chamber 14 is formed in a substantially elliptical shape that is long in the scanning direction (left-right direction in FIG. 2) in plan view.

  As shown in FIGS. 3 and 4, communication holes 15 and 16 are formed at positions where the base plate 11 overlaps both longitudinal ends of the pressure chambers 14 in a plan view, respectively. The manifold plate 12 is formed with a manifold 17 extending in the paper feeding direction (vertical direction in FIG. 2). 2 to 4, the manifold 17 overlaps the left half of the pressure chambers 14 arranged on the left side and the right half of the pressure chambers 14 arranged on the right side in plan view. Has been placed. The manifold 17 is connected to an ink supply port 18 formed in a vibration plate 30 described later, and ink is supplied from an ink tank (not shown) through the ink supply port 18. In addition, a communication hole 19 that is continuous with the communication hole 16 is formed at a position of the manifold plate 12 that overlaps the end of each pressure chamber 14 opposite to the manifold 17 in plan view. Furthermore, nozzles 20 are respectively formed at positions where the nozzle plate 13 overlaps the communication holes 19 in plan view. These nozzles 20 are formed, for example, by performing excimer laser processing on a polymer synthetic resin substrate such as polyimide.

  As shown in FIG. 4, the manifold 17 communicates with the pressure chambers 14 through the communication holes 15, and the pressure chambers 14 communicate with the nozzles 20 through the communication holes 16 and 19. Yes. As described above, a plurality of individual ink flow paths 21 extending from the manifold 17 to the nozzles 20 through the pressure chambers 14 are formed in the flow path unit 2.

  Next, the piezoelectric actuator 3 will be described. As shown in FIGS. 2 to 5, the piezoelectric actuator 3 includes a vibration plate 30 disposed on the upper surface of the cavity plate 10 and a piezoelectric element formed on the upper surface of the vibration plate 30 (the surface opposite to the pressure chamber 14). A layer 31, a plurality of individual electrodes 32 formed on the upper surface of the piezoelectric layer 31 so as to correspond to the plurality of pressure chambers 14, and a flexible printed wiring board (FPC) for supplying a driving voltage to the plurality of individual electrodes 32 40. In FIG. 2 and FIG. 3, the FPC 40 that should originally be indicated by a solid line is indicated by a two-dot chain line in order to make the drawings easy to see. The cavity plate 10 of the flow path unit 2 corresponds to a support member that supports the vibration plate 30, and the cavity plate 10 also constitutes a part of the piezoelectric actuator 3. Further, the plurality of pressure chambers 14 formed in the cavity plate 10 correspond to escape portions that allow the deformation of the diaphragm 30 to escape, and the girders 10 a joined to the diaphragm 30 correspond to joint portions.

  The diaphragm 30 is a plate made of a substantially rectangular metal material in plan view, and is made of, for example, an iron-based alloy such as stainless steel, a copper-based alloy, a nickel-based alloy, or a titanium-based alloy. The diaphragm 30 is disposed on the upper surface of the cavity plate 10 so as to cover the plurality of pressure chambers 14, and is joined to the beam portion 10 a of the cavity plate 10. Further, the metal diaphragm 30 has conductivity, and the diaphragm 30 is always held at the ground potential. And it also serves as a common electrode (first electrode) for applying an electric field to the piezoelectric layer 31 sandwiched between the diaphragm 30 and the individual electrode 32.

  On the upper surface of the diaphragm 30, a piezoelectric layer 31 mainly composed of lead zirconate titanate (PZT), which is a solid solution and is a ferroelectric substance, is formed of lead titanate and lead zirconate. As shown in FIGS. 2 to 5, the piezoelectric layer 31 is continuously formed over the plurality of pressure chambers 14 on the upper surface of the vibration plate 30.

  A plurality of individual electrodes 32 (second electrodes) having an elliptical planar shape that is slightly smaller than the pressure chamber 14 are formed on the upper surface of the piezoelectric layer 31. Each of the plurality of individual electrodes 32 is formed at a position overlapping the central portion of the corresponding pressure chamber 14 in plan view. That is, as shown in FIG. 2, the plurality of individual electrodes 32 are arranged in two rows in the paper feed direction (vertical direction in FIG. 2) corresponding to the plurality of pressure chambers 14, respectively. The individual electrode 32 is made of a conductive material such as gold, copper, silver, palladium, platinum, or titanium. Further, on the upper surface of the piezoelectric layer 31, each of the plurality of individual electrodes 32 is parallel to the longitudinal direction of the individual electrodes 32 (the left-right direction in FIG. 2) from the end on the manifold 17 side to the region facing the beam portion 10 a. A plurality of wiring portions 35 extending are also formed.

  An FPC 40 (wiring member) is disposed above the piezoelectric layer 31 and the plurality of individual electrodes 32. The FPC 40 is formed of a synthetic resin material such as polyimide and has a flexible base 41 and a lower surface (surface on the piezoelectric layer 31 side) of the base 41 corresponding to a plurality of individual electrodes 32. And a plurality of wiring portions 42. In addition, as shown in FIG. 4, terminal portions 42 a are provided at the end portions of the respective wiring portions 42. Each terminal portion 42a is electrically conductive with solder, conductive paste, or the like at a contact 35a provided on an end of each wiring portion 35 formed on the upper surface of the piezoelectric layer 31 on the side opposite to each individual electrode 32. It is joined via a material 45. Further, the FPC 40 is connected to a driver IC (not shown) that is a drive circuit. That is, the driver IC and the plurality of wiring portions 35 are electrically connected by the FPC 40, and a driving voltage is selectively applied from the driver IC to the plurality of individual electrodes 32 through the FPC 40.

  Next, the operation of the piezoelectric actuator 3 during the ink discharge operation will be described. When a drive voltage is selectively applied from a driver IC to a desired individual electrode 32, the individual electrode 32 on the upper side of the piezoelectric layer 31 to which the drive voltage is supplied and the lower side of the piezoelectric layer 31 held at the ground potential. The potentials of the diaphragm 30 serving as the common electrode are different from each other, and an electric field in the vertical direction is generated in the drive portion of the piezoelectric layer 31 sandwiched between the individual electrode 32 to which the drive voltage is supplied and the diaphragm 30. Then, the drive part of the piezoelectric layer 31 contracts in the horizontal direction perpendicular to the vertical direction that is the polarization direction. Here, since the vibration plate 30 is joined to the beam portion 10 a of the cavity plate 10, the vibration plate 30 is deformed so as to protrude toward the pressure chamber 14 as the driving portion of the piezoelectric layer 31 contracts. Accordingly, the volume in the pressure chamber 14 is reduced, pressure is applied to the ink in the pressure chamber 14, and ink droplets are ejected from the nozzle 20 communicating with the pressure chamber 14.

  As will be described later, in the manufacturing process of the piezoelectric actuator 3, a conductive material 45 such as solder or conductive paste is melted on the surface of the contact 35 a of the wiring portion 35, and the FPC 40 is melted by the molten conductive material 45. The plurality of terminal portions 42a and the contact points 35a of the plurality of wiring portions 35 are joined. Here, like the individual electrodes 32, the surfaces of the plurality of wiring parts 35 made of a conductive material have good wettability, and the conductive material 45 such as solder melted on the surface of the contact 35a is individually transmitted through the wiring parts 35. It is easy to flow to the electrode 32. When the conductive material 45 flows out to the surface of the individual electrode 32, the conductive material 45 inhibits the deformation of the piezoelectric layer 31 when a drive voltage is applied to the individual electrode 32. 3 will not work properly. Further, the molten conductive material 45 may flow out to another wiring part 35 adjacent to the arrangement direction of the individual electrodes 32 (vertical direction in FIG. 3), and a short circuit may occur between the two wiring parts 35. .

  Therefore, in the piezoelectric actuator 3 of the present embodiment, a cooling liquid 60 (see FIG. 6C) for cooling the molten conductive material 45 is injected (filled) into the upper surface of the beam portion 10a of the cavity plate 10. ) A possible cooling channel 46 is formed in a groove shape whose upper part is closed by the diaphragm 30. That is, the groove portion is formed by the groove-shaped cooling flow path 46 being closed by the diaphragm 30. As shown in FIGS. 2 and 3, the cooling flow path 46 starts from the region facing the wiring portion 35 between each individual electrode 32 and the contact point 35 a, from the wiring portion 35 and the wiring portion 35 adjacent thereto. An individual cooling channel 47 (corresponding to a liquid filling part) extending in an arc shape is provided up to a region facing between the two contact points 35a. That is, each individual cooling channel 47 traverses the wiring portion 35 between the individual electrode 32 and the contact 35a, and further extends to the upper and lower regions of the contact 35a of the corresponding wiring portion 35 in FIG. It is formed so as to surround 35a from the individual electrode 32 side.

  In addition, the two left and right rows of individual cooling channels 47 respectively corresponding to the plurality of individual electrodes 32 arranged in two rows in the paper feeding direction (up and down direction in FIG. 2) communicate with each other and extend in the paper feeding direction. They communicate with each other via a path 48. Further, the two right and left rows of individual cooling channels 47 communicate with each other via a communication channel 49 extending in the scanning direction (left and right direction in FIG. 2) in the region on the upper end side in FIG. Accordingly, all the individual cooling channels 47 of the cooling channel 46 communicate with each other via the communication channels 48 and 49. Further, both ends of the cooling channel 46 are drawn downward in FIG. 2 and connected to an inlet 50 and an outlet 51 formed in the diaphragm 30, respectively. Therefore, when the cooling liquid 60 is injected into the cooling flow path 46 from the injection port 50, the cooling liquid 60 sequentially flows through the plurality of individual cooling flow paths 47 and is discharged from the discharge port 51.

  When the terminal portion 42 a of the FPC 40 and the contact point 35 a of the wiring portion 35 are joined by the conductive material 45, the conductive material 45 is melted while flowing the cooling liquid 60 into the cooling flow path 46. Then, the conductive material 45 flowing out from the surface of the contact 35a to the surroundings is cooled by the cooling liquid 60 flowing in each individual cooling channel 47. In this way, when the conductive material 45 is cooled, its viscosity increases and no longer flows, so that the conductive material 45 is prevented from flowing from the surface of the contact 35a to the surroundings. The bonding process between the FPC 40 and the wiring part 35 will be described in more detail in the description of the manufacturing method described below.

  Next, a method for manufacturing the inkjet head 1 will be described. First, the manifold 17 and a plurality of individual ink flow paths 21 each including the nozzle 20 and the pressure chamber 14 are formed on the four plates 10 to 13 constituting the flow path unit 2 by etching or the like. At this time, the aforementioned cooling flow path 46 including the plurality of individual cooling flow paths 47 is simultaneously formed in the beam portion of the cavity plate 10. Then, as shown in FIG. 6A, the four plates 10 to 13 constituting the flow path unit 2 and the vibration plate 30 are laminated, and then joined by bonding with an adhesive or diffusion bonding.

  Next, as shown in FIG. 6B, the piezoelectric layer 31 is formed on the upper surface of the diaphragm 30. Here, the piezoelectric layer 31 can be formed using, for example, an aerosol deposition method (AD method) in which very small particles of a piezoelectric material are sprayed onto a substrate to collide at high speed and are deposited on the substrate. Alternatively, it can also be formed by sputtering, chemical vapor deposition (CVD), sol-gel method, solution coating method, or hydrothermal synthesis method. It is also possible to form the piezoelectric layer 31 by attaching a piezoelectric sheet obtained by firing a PZT green sheet to the diaphragm 30. Further, a plurality of individual electrodes 32 and a plurality of wiring portions 35 are formed on the upper surface of the piezoelectric layer 31 by screen printing or the like.

  Next, as shown in FIG. 6C, a pressure device (not shown) such as a pump for pressurizing the cooling liquid 60 is connected to the inlet 50, and the cooling channel 46 is connected by this pressure device. The cooling liquid 60 at room temperature (for example, about 15 ° C.) is pressurized and injected (filled) into the inside (filling step). Here, since the plurality of individual cooling channels 47 of the cooling channel 46 provided corresponding to the plurality of wiring portions 35 (contacts 35a) are all in communication with each other, the cooling injected from the injection port 50 is performed. The working liquid 60 flows through the plurality of individual cooling channels 47 in order and is discharged from the discharge port 51. Therefore, by continuously pressurizing and injecting the cooling liquid 60 by the pressurizing device, the cooling liquid 60 is forced and continuously flowed in the cooling flow path 46 (a plurality of individual cooling flow paths 47). It will be. Here, as the cooling liquid 60, it is preferable to use a liquid having a large specific heat and containing water as a main component. Further, the cooling liquid 60 may be ethylene glycol, an antifreeze liquid obtained by mixing ethylene glycol in water, or an alternative chlorofluorocarbon such as hydrochlorofluorocarbon or hydrofluorocarbon.

  Next, the FPC 40 is disposed above the piezoelectric layer 31 with a conductive material 45 such as solder or conductive paste interposed between the contacts 35a of the plurality of wiring portions 35 and the terminal portions 42a of the FPC 40. Then, the conductive material 45 is heated to a predetermined melting temperature (for example, 200 ° C. or higher), and the terminal portion 42a of the FPC 40 and the contact point 35a of the wiring portion 35 are bonded by the molten conductive material 45 (bonding step). . In this joining step, for example, as shown in FIG. 6C, a pair of heat blocks 52 and 53 are installed on the upper side of the FPC 40 and the lower side of the nozzle plate 13, and the pair of upper and lower heat blocks 52, The FPC 40 and the wiring part 35 can be joined by heating the conductive material 45 by 53 and pressing the FPC 40 toward the wiring part 35 while melting the conductive material 45. Alternatively, the FPC 40 and the wiring part 35 are pressed by pressing the FPC 40 toward the wiring part 35 with a jig while irradiating the FPC 40 side with an ion beam, infrared light, laser light or the like to melt the conductive material 45. It can also be joined.

  At this time, a part of the molten conductive material 45 tends to flow out from the surface of the contact 35a. However, the cooling liquid 60 is continuously flowed into the plurality of individual cooling channels 47 formed in the beam portion 10a of the cavity plate 10 corresponding to the plurality of individual electrodes 32 (wiring portions 35). Yes. Each individual cooling channel 47 is opposed to the wiring part 35 between the corresponding individual electrode 32 and the contact point 35a, and is arranged so as to cross the wiring part 35. Therefore, the heat of the high-temperature conductive material 45 flowing out from the surface of the contact point 35a toward the individual electrode 32 through the wiring portion 35 is taken away by the low-temperature cooling liquid 60 flowing in the individual cooling flow path 47, and the wiring In the middle of the portion 35, the conductive material 45 is rapidly cooled. For this reason, the viscosity of the conductive material 45 suddenly rises and solidification starts, and no longer flows. Therefore, it is possible to reliably prevent the conductive material 45 from adhering to the surface of the individual electrode 32 and inhibiting the deformation of the piezoelectric layer 31.

  In addition, the communication channel 48 connected to the individual cooling channel 47 is formed in a region between the contacts 35a of the two wiring portions 35 adjacent to each other in the arrangement direction of the individual electrodes 32 (the left-right direction in FIG. 3). Therefore, the conductive material 45 that flows out from the surface of the contact point 35a of a certain wiring part 35 toward the contact point 35a of the adjacent wiring part 35 has a low temperature that flows in the communication channel 48 formed between the adjacent contact point 35a. The cooling liquid 60 is rapidly cooled. Therefore, the conductive material 45 does not flow from a certain contact 35a to the adjacent wiring part 35, and a short circuit between the wiring parts 35 can be prevented.

  A plurality of individual cooling flow paths 47 respectively corresponding to the plurality of wiring portions 35 communicate with each other, and while the cooling liquid 60 is forced and continuously passed through the plurality of individual cooling flow paths 47, the conductive material 45. As a result of the joining step being performed by melting the cooling liquid 60, the cooling effect of the conductive material 45 by the cooling liquid 60 is further enhanced as compared with the case where the cooling liquid 60 is not flowed. Therefore, it can suppress more reliably that the electroconductive material 45 flows out from the contact 35a to the circumference | surroundings. In addition, by using a liquid having a high specific heat and an inexpensive water as the main component as the cooling liquid 60, the molten conductive material 45 can be effectively cooled while keeping the manufacturing cost low.

  Next, modified embodiments in which various modifications are made to the first embodiment will be described. However, components having the same configuration as in the first embodiment are denoted by the same reference numerals and description thereof is omitted as appropriate.

<First modification>
The diaphragm 30 does not necessarily have to serve as a common electrode, and the common electrode 34 (first electrode) may be provided separately from the diaphragm 30 as shown in FIG. However, when the diaphragm 30 is a metal plate, an insulating material layer is formed on the upper surface of the diaphragm 30 on which the common electrode 34 is formed, so that the upper surface of the diaphragm 30 has an insulating property. Need to be. When the diaphragm 30 is made of a silicon material, the upper surface of the diaphragm 30 may be oxidized to have insulation. When the diaphragm 30 is made of an insulating material such as a ceramic material or a synthetic resin material, the common electrode 34 is directly formed on the upper surface of the diaphragm 30.

<Second modification>
As shown in FIG. 8, the wiring part 35 </ b> B may be formed such that the width is partially narrowed between the individual electrode 32 and the contact point 35 a. In this configuration, since the amount of the conductive material 45 flowing from the contact point 35a toward the individual electrode 32 through the wiring portion 35B having good wettability is reduced, the conductive material 45 adheres to the surface of the individual electrode 32. Can be more reliably prevented.

<Third modification>
As shown in FIG. 9, each individual cooling channel 47 </ b> C of the cooling channel 46 </ b> C may be formed in an annular shape so as to surround the contact point 35 a of the wiring part 35 in a plan view. In this case, it is possible to more reliably prevent the conductive material 45 from flowing out from the contact point 35a to the periphery thereof.

<Fourth modification>
When there is not much possibility that a short circuit between the contact points 35a occurs, for example, when the distance between the contact points of the two adjacent wiring portions 35 is sufficiently large, the two cooling flow paths adjacent to each other as in the first embodiment are used. It is not particularly necessary to be formed between the contact points 35a of the wiring part 35, and any structure that can mainly prevent the conductive material 45 from flowing from the contact point 35a through the wiring part 35 to the individual electrode 32 may be used. For example, as shown in FIG. 10, the cooling flow path 46 </ b> D extends in the arrangement direction of the individual electrodes 32 (up and down direction in FIG. 10) across the plurality of wiring portions 35 between the individual electrodes 32 and the contacts 35 a. It may be formed.

<Fifth modification>
On the contrary, the conductive material 45 flowing along the wiring part 35 from the contact 35a is unlikely to reach the individual electrode 32 such that the wiring part 35 is long and the distance between the individual electrode 32 and the contact point 35a is sufficiently large. In this case, it is not particularly necessary that the cooling channel is formed in the region facing the wiring portion 35 between the individual electrode 32 and the contact 35a as in the first embodiment, and a short circuit between the adjacent contacts 35a. Any configuration can be used as long as it can be mainly prevented. For example, as shown in FIG. 11, each cooling channel 47E of the cooling channel 46E is not formed in a region facing the wiring part 35 between the individual electrode 32 and the contact point 35a, and both sides of the contact point 35a. In this region (a region facing between the contacts 35a of the two wiring portions 35), the wiring portion 35 may extend in parallel to surround the contact 35a of the wiring portion 35 from the side opposite to the individual electrode 32. .

<Sixth modification>
When it is necessary to prevent the conductive material 45 from flowing out from the contact point 35a of the wiring part 35 to the side opposite to the individual electrode 32, for example, as shown in FIG. On the side opposite to the individual electrodes 32, the electrodes may be formed so as to extend in the arrangement direction of the individual electrodes 32 (the vertical direction in FIG. 12).

<Seventh modification>
The cooling flow path does not necessarily have to be formed in the cavity plate. As shown in FIG. 13, the cooling flow path 46G (individual cooling flow path 47G) is formed at a portion where the vibration plate 30G is joined to the cavity plate 10G. It may be formed. Alternatively, it may be formed over the diaphragm and the cavity plate.

<Eighth modification>
As shown in FIGS. 14 to 16, a plurality of liquid filling portions 46H respectively corresponding to the plurality of wiring portions 35 are formed in the cavity plate 10H, and the plurality of liquid filling portions 46H are communicated with the base plate 11H therebelow. The communication flow path 48H to be made may be formed. Each liquid filling portion 46H has a substantially elliptical planar shape that is long in the paper feed direction (vertical direction in FIG. 14) in plan view in a region facing the wiring portion 35 between the individual electrode 32 and the contact point 35a. It is formed by a hole. The length in the longitudinal direction of the liquid filling portion 46H is substantially equal to the width of the wiring portion 35, and the length (width) in the short direction of the liquid filling portion 46H is substantially equal to the width of the communication channel 48H. The communication channel 48H is formed by a groove extending in the paper feed direction on the upper surface side of the base plate 11H. When the terminal portion 42a of the FPC 40 and the contact point 35a of the wiring portion 35 are joined, the cooling liquid 60 is continuously passed through the communication channel 48H, and the communication channel 48H is supplied to the plurality of liquid filling units 46H. The conductive material 45 is heated and melted while being filled with the cooling liquid 60. Also in the modified embodiment 8, since the conductive material 45 flowing out from the contact 35a through the wiring portion 35 toward the individual electrode 32 is cooled by the cooling liquid 60 filled in the liquid filling portion 46H, the conductive material 45 45 can be prevented from adhering to the surface of the individual electrode 32.

  In the present embodiment and each modified embodiment, the cooling liquid 60 is used to cool the conductive material 45, but instead of the cooling liquid 60, for example, a gas such as air, nitrogen, helium gas, or flon gas, or A refrigerant such as aerosol may be used. At this time, the conductive material 45 can be efficiently cooled by forcibly flowing the refrigerant in the cavity such as the individual cooling channel 47 using a pressurizing device such as a pump. Moreover, when using air as a refrigerant | coolant, the air in a cavity part can also be made to flow with the flow of the air which arises by a convection instead of using a pressurization apparatus. In this case, it is possible to omit a pressurizing device that pressurizes and injects the refrigerant into the cavity during the joining step, and the manufacturing equipment can be simplified. Moreover, since air is used as the refrigerant, it is not necessary to prepare a separate refrigerant, and the manufacturing cost can be reduced.

  Next, a second embodiment of the present invention will be described. The inkjet head 71 of the second embodiment is different from the first embodiment in that a cooling flow path 46 (see FIGS. 2 to 4) for flowing the cooling liquid 60 is not formed. Other configurations are the same. Therefore, components having the same configuration as in the first embodiment are denoted by the same reference numerals and description thereof is omitted as appropriate.

  As shown in FIGS. 17 to 19, the ink jet head 71 of the second embodiment is disposed on the upper surface of the flow path unit 72 in which an ink flow path including a plurality of pressure chambers 14 is formed. The piezoelectric actuator 3 is provided.

  The flow path unit 72 includes a cavity plate 80, a base plate 11, a manifold plate 12, and a nozzle plate 13, and these four plates 80, 11, 12, and 13 are joined in a laminated state. A plurality of pressure chambers 14 are formed in the cavity plate 80 and have substantially the same configuration as the cavity plate 10 of the first embodiment, but a cooling channel 46 (see FIGS. 2 to 4) is formed. There are no differences. The base plate 11, the manifold plate 12, and the nozzle plate 13 are the same as those in the first embodiment, and the description thereof is omitted. In the flow path unit 72, an individual ink flow path 21 extending from the manifold 17 to the nozzle 20 through the pressure chamber 14 is formed.

  The piezoelectric actuator 3 has the same configuration as that of the first embodiment, and includes a diaphragm 30, a piezoelectric layer 31, a plurality of individual electrodes 32, a plurality of wiring portions 35, an FPC 40, and the like. And the terminal part 42a of FPC40 is joined to the contact 35a of the some wiring part 35 formed in the upper surface of the piezoelectric layer 31 via the electroconductive materials 45, such as solder.

  Next, a method for manufacturing the ink jet head 71 of the second embodiment will be described. However, since the process until the terminal portion 42a of the FPC 40 and the contact point 35a of the wiring portion 35 are joined is the same as that in the first embodiment (see FIGS. 6A and 6B), the FPC 40 and the wiring portion 35 are used. A process of joining the two will be described in particular.

  After connecting the ink supply port 18 (see FIG. 17) and a pressurizing device such as a pump, as shown in FIG. 20, the manifold 17 formed in the flow path unit 72 by this pressurizing device, and this A cooling liquid 60 at normal temperature (for example, about 15 ° C.) is pressurized and injected (filled) into the individual ink flow path 21 extending from the manifold 17 to the nozzle 20 via the pressure chamber 14 (filling step). Further, the cooling liquid 60 is ejected from the nozzle 20, and the cooling liquid 60 is continuously flowed in the individual ink flow path 21.

  In this state, the FPC 40 is disposed on the upper side of the piezoelectric layer 31, and a conductive material 45 such as solder or conductive paste is disposed between the terminal portion 42 a of the FPC 40 and the contacts 35 a of the plurality of wiring portions 35. Then, the conductive material 45 is heated to a predetermined melting temperature (for example, 200 ° C. or higher), and the terminal portion 42a of the FPC 40 and the contact point 35a of the wiring portion 35 are bonded by the molten conductive material 45 (bonding step). Here, as a method for heating the conductive material 45, as shown in FIG. 20, a method using a pair of upper and lower heater blocks 81 and 82 that are in contact with the FPC 40 and the nozzle plate 13, respectively, ion beam, infrared, or Various methods such as a method of irradiating laser light can be employed.

  Here, a part of the conductive material 45 melted in the joining process tends to flow from the surface of the contact 35a to the surroundings, but this conductive material 45 is a low-temperature material that continuously flows in the individual ink flow path 21. Since the cooling liquid 60 is deprived of heat and cooled, the viscosity rapidly increases and solidification starts. Therefore, it is possible to suppress the conductive material 45 from flowing out from the contact point 35a. In the second embodiment, unlike the first embodiment, the joining step is performed while flowing the cooling liquid 60 in the ink flow path such as the manifold 17 or the individual ink flow path 21. It is not necessary to form a special flow path (such as the cooling flow path 46 of the first embodiment) separately from the ink flow path, which is advantageous in terms of manufacturing cost.

  In the present embodiment, the cooling liquid 60 is used as a coolant for cooling the conductive material 45, but the coolant is not limited to a liquid, for example, a gas such as air, nitrogen, chlorofluorocarbon, helium, or a coolant such as an aerosol. May be used.

  In the first embodiment and the second embodiment described above, the joining process is performed while the cooling liquid 60 is forced and continuously flowed. In terms of efficiently cooling the conductive material 45, it is preferable to forcibly flow the cooling liquid 60, but the conductive material 45 can be cooled without forcibly flowing the cooling liquid 60. is there. For example, the discharge port 51 of the cooling flow path 46 (see FIG. 2) of the first embodiment or the nozzle 20 of the individual ink flow path 21 of the second embodiment is sealed, and the flow paths 46 and 21 are filled with these. The joining step may be performed in a state where the cooling liquid 60 is filled (without being discharged to the outside). In this case, the cooling efficiency is reduced as compared with the case where the cooling liquid 60 is forced to flow. However, since a pressurizing device or the like for injecting the cooling liquid 60 under pressure is unnecessary, the manufacturing equipment is simplified. It becomes possible to do.

  As mentioned above, although the form which applied this invention to the inkjet head was described taking the 1st Embodiment and 2nd Embodiment as an example, the form which can apply this invention is these 1st Embodiment and 2nd Embodiment. It is not limited. For example, the present invention can be applied to various liquid transfer devices that transfer liquids other than ink. Furthermore, the actuator to which the present invention can be applied is not limited to an actuator used for applying pressure to a liquid. That is, as long as the object is driven by deforming the diaphragm joined to the joint portion of the support member, it can be applied to an actuator used for other purposes. In this case, the relief part provided in the support member does not necessarily need to be a hole formed in the support member, and the escape part may have a shape that does not hinder the deformation of the diaphragm. As an example, FIG. 21 shows a piezoelectric actuator 103 having a configuration in which the flow path unit 2 of the inkjet head shown in FIG. A region of the surface of the support member 110 on the diaphragm 30 side that overlaps with the individual electrode 32 in a plan view is substantially the same shape as the individual electrode 32 and has a groove shape that is open to the surface on the diaphragm 30 side. An escape portion 110B is formed. Thus, by forming the escape portion 110B in the support member 110, the girder portion 110A is defined. A cooling water passage 46 having the same shape as that of the first embodiment is formed in the support member beam 110A. The thickness of the relief portion 110B of the support member is formed thinner than the thickness of the girder portion 110A, and the bottom surface 110C of the relief portion 110B can be vibrated by the pressure wave generated by driving the diaphragm 30. As shown in this example, the relief portion may be a recess provided in the support member.

FIG. 1 is a schematic configuration diagram of an ink jet printer according to a first embodiment of the present invention. FIG. 2 is a plan view of the inkjet head. FIG. 3 is a partially enlarged view of FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. FIG. 5 is a cross-sectional view taken along line VV in FIG. 6A and 6B are diagrams illustrating a manufacturing process of the piezoelectric actuator according to the first embodiment. FIG. 6A is a process of joining the flow path unit and the diaphragm, and FIG. 6B is a piezoelectric layer, individual electrodes, and wiring. 6C shows a step of bonding the wiring portion on the upper surface of the piezoelectric layer and the terminal portion of the FPC. FIG. 7 is a cross-sectional view corresponding to FIG. 4 according to a first modification of the first embodiment. FIG. 8 is an enlarged plan view corresponding to FIG. 3 according to the modified embodiment 2 of the first embodiment. FIG. 9 is an enlarged plan view corresponding to FIG. 3 according to Modification 3 of the first embodiment. FIG. 10 is an enlarged plan view corresponding to FIG. 3 according to Modification 4 of the first embodiment. FIG. 11 is an enlarged plan view corresponding to FIG. 3 according to the modified embodiment 5 of the first embodiment. FIG. 12 is an enlarged plan view corresponding to FIG. 3 according to Modification 6 of the first embodiment. FIG. 13 is a cross-sectional view corresponding to FIG. 4 according to Modification 7 of the first embodiment. FIG. 14 is an enlarged plan view corresponding to FIG. 3 according to the modified embodiment 8 of the first embodiment. 15 is a cross-sectional view taken along line XV-XV in FIG. 16 is a cross-sectional view taken along line XVI-XVI in FIG. FIG. 17 is a plan view of an ink jet head according to the second embodiment of the present invention. FIG. 18 is a partially enlarged view of FIG. 19 is a cross-sectional view taken along line XIX-XIX in FIG. FIG. 20 is a diagram illustrating a process of bonding the wiring portion on the upper surface of the piezoelectric layer and the terminal portion of the FPC. FIG. 21 is a cross-sectional view corresponding to FIG. 4 of a piezoelectric actuator provided with a support member having a groove-shaped relief portion.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet head 2 Flow path unit 3 Piezoelectric actuator 10, 10G, 10H Cavity plate 10a Girder part 14 Pressure chamber 21 Individual ink flow path 30, 30G Diaphragm 31 Piezoelectric layer 32 Individual electrode (second electrode)
34 Common electrode (first electrode)
35B Wiring part 35a Contact 40 Flexible printed wiring board (FPC)
42a Terminal part 45 Conductive material 46, 46C, 46D, 46E, 46F, 46G Cooling channel 46H Liquid filling unit 47, 47C, 47E, 47G Individual cooling channel 60 Cooling liquid 71 Inkjet head 72 Channel unit

Claims (21)

A diaphragm,
A supporting member having a deformation relief part for escaping deformation of the diaphragm and a joint part joined to the diaphragm;
A piezoelectric layer disposed on the opposite side of the diaphragm from the support member;
A first electrode disposed on a surface of the piezoelectric layer on the vibration plate side; and a second electrode disposed on a region of the surface of the piezoelectric layer opposite to the vibration plate facing the deformation relief portion; ,
A wiring portion extending from the second electrode to a region facing the bonding portion on the surface of the piezoelectric layer opposite to the diaphragm;
A wiring member for supplying a driving voltage to the second electrode, and having a terminal portion joined to the contact of the wiring portion via a conductive material;
A piezoelectric actuator, wherein a cavity is provided in a portion of at least one of the diaphragm and the joint that faces the wiring portion between the second electrode and the contact.   2. The piezoelectric actuator according to claim 1, wherein the hollow portion is a hole through which a coolant flows when the wiring portion and the terminal portion are joined with the conductive material.   The piezoelectric actuator according to claim 2, wherein the refrigerant is a liquid.   The piezoelectric actuator according to claim 2, wherein the refrigerant is a gas. The deformation relief portion includes a plurality of relief portions, and includes a plurality of the relief portions arranged adjacent to each other along a plane, and a plurality of second electrodes respectively corresponding to the plurality of relief portions,
A plurality of the cavity portions are provided corresponding to the plurality of second electrodes, respectively.
The piezoelectric actuator according to claim 2, wherein the plurality of hollow portions communicate with each other.   6. The piezoelectric actuator according to claim 5, wherein each of the hollow portions extends to a region facing between the contacts of the two wiring portions respectively corresponding to two adjacent second electrodes.   The piezoelectric actuator according to claim 1, wherein the hollow portion is formed in an annular shape surrounding a contact point of the wiring portion.   8. The piezoelectric actuator according to claim 1, wherein the wiring portion is partially narrowed between the second electrode and the contact point. 9. A diaphragm,
A support member having a plurality of escape portions that allow deformation of the diaphragm and joint portions joined to the diaphragm;
A piezoelectric layer disposed on the opposite side of the diaphragm from the support member;
A first electrode disposed on the surface of the piezoelectric layer on the vibration plate side, and a plurality of surfaces disposed on regions of the surface of the piezoelectric layer opposite to the vibration plate facing the plurality of escape portions. A second electrode;
A plurality of wiring portions respectively extending from a plurality of second electrodes to a region facing the bonding portion on the surface of the piezoelectric layer opposite to the diaphragm;
A wiring member that has a plurality of terminal portions bonded to the contacts of the plurality of wiring portions through a conductive material, and supplies a driving voltage to the plurality of second electrodes,
A cavity portion is provided in a portion of at least one of the diaphragm and the joint portion that faces a portion between the contact points of the two wiring portions respectively corresponding to the two adjacent second electrodes. A characteristic piezoelectric actuator.   The piezoelectric actuator according to claim 9, wherein each of the hollow portions is a hole through which a coolant flows when the wiring portion and the terminal portion are joined with the conductive material.   The piezoelectric actuator according to claim 10, wherein the refrigerant is a liquid.   The piezoelectric actuator according to claim 10, wherein the refrigerant is a gas. A liquid transfer apparatus comprising: a liquid flow path including a plurality of pressure chambers arranged along a plane; and a piezoelectric actuator that changes the volume of the pressure chamber to apply pressure to the liquid in the pressure chamber,
The piezoelectric actuator is
A pressure chamber plate in which the plurality of pressure chambers are formed;
A diaphragm that is joined at a joint of the pressure chamber plate and covers the plurality of pressure chambers;
A piezoelectric layer disposed on the opposite side of the diaphragm from the pressure chamber plate;
A common electrode formed on the surface of the piezoelectric layer on the diaphragm side, and a plurality of individual electrodes respectively disposed in regions facing the plurality of pressure chambers on the surface of the piezoelectric layer opposite to the diaphragm. When,
A plurality of wiring portions each extending from the individual electrode to a region facing the bonding portion on the surface of the piezoelectric layer opposite to the diaphragm;
A wiring member for supplying a driving voltage to the plurality of individual electrodes, and having a plurality of terminal portions bonded to the contacts of the plurality of wiring portions through a conductive material, respectively.
A liquid transfer device, wherein at least one of the diaphragm and the joint portion is provided with a cavity portion in each portion facing the wiring portion between the individual electrode and the contact point.   The liquid transfer device according to claim 13, wherein the hollow portion is a hole through which a coolant flows when the wiring portion and the terminal portion are joined by the conductive material.   The liquid transfer device according to claim 14, wherein the refrigerant is a liquid.   The liquid transfer device according to claim 14, wherein the refrigerant is a gas. A method for manufacturing a piezoelectric actuator according to claim 3,
A filling step of filling the cavity with a cooling liquid;
A method for manufacturing a piezoelectric actuator, comprising: a step of heating the conductive material and bonding the wiring portion and the terminal portion with the molten conductive material.   The method for manufacturing a piezoelectric actuator according to claim 17, wherein the cooling liquid includes water as a main component.   The method for manufacturing a piezoelectric actuator according to claim 17, wherein in the filling step, the cooling liquid filled in the cavity is forced to flow. A flow path unit including a plurality of pressure chambers arranged along a plane;
A diaphragm that is connected at the joint of the flow path unit and covers the plurality of pressure chambers, a piezoelectric layer disposed on the opposite side of the diaphragm to the pressure chamber, and a surface of the piezoelectric layer on the diaphragm side A plurality of individual electrodes respectively disposed in regions facing the plurality of pressure chambers on the surface of the piezoelectric layer opposite to the diaphragm, and the diaphragm of the piezoelectric layer A piezoelectric actuator having a plurality of wiring portions each extending from the individual electrode to a region facing the bonding portion on the opposite surface, and a wiring member including a plurality of terminal portions respectively bonded to the plurality of wiring portions;
A method of manufacturing a liquid transfer device provided in the flow path unit or the piezoelectric actuator and having a refrigerant flow path through which a refrigerant flows,
A filling step of filling the refrigerant flow path with the refrigerant;
A liquid comprising: a bonding step of placing and heating a conductive material between the wiring portion and the terminal portion, and bonding the wiring portion and the terminal portion with the molten conductive material; Manufacturing method of transfer device. 21. The method for manufacturing a liquid transfer device according to claim 20, wherein the refrigerant channel is a channel including the pressure chamber, and the refrigerant is a liquid.

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