JP5217855B2 - Method for manufacturing piezoelectric actuator unit, method for manufacturing liquid transfer device, piezoelectric actuator unit and liquid transfer device - Google Patents

Description

  The present invention relates to a method for manufacturing a piezoelectric actuator unit in which a wiring member is disposed so as to face the surface of the piezoelectric layer, a method for manufacturing a liquid transfer device including such a piezoelectric actuator unit, and the surface of the piezoelectric layer. The present invention relates to a piezoelectric actuator unit in which wiring members are arranged so as to face each other, and a liquid transfer device including such a piezoelectric actuator unit.

  In Patent Document 1, when a recording head that ejects ink droplets from nozzles by applying pressure to ink in a pressure chamber by a piezoelectric actuator is manufactured, an upper surface of a piezoelectric sheet (piezoelectric layer) disposed at the uppermost position is used. A bump is formed on the surface of the land portion of the arranged individual electrode, and an uncured thermosetting synthetic resin layer is formed on the lower surface of the FPC (Flexible Printed Circuit) (flexible wiring member) on which the terminal portion and wiring are formed. It is described that the piezoelectric sheet and the FPC are bonded together by forming and heating the FPC while pressing it toward the piezoelectric sheet, with the bumps penetrating the synthetic resin layer and contacting the terminal portion.

JP 2005-35847 A

  Generally, FPC has a conductive layer formed on the surface of a substrate such as polyimide, and an insulating resist material that covers the conductive layer is formed. Since the thermal expansion coefficient of the substrate is larger than that of a piezoelectric sheet, As described in Document 1, when the FPC is heated while being pressed toward the piezoelectric sheet, the FPC flexes to the piezoelectric sheet side or the opposite side of the piezoelectric sheet due to the difference in linear expansion coefficient between the FPC and the piezoelectric sheet. Will end up. When the surface of the FPC is heated by pressing a bar heater or the like, the FPC expanded by the pressing force from above is easily bent toward the piezoelectric sheet side. If the FPC is bent toward the piezoelectric sheet and comes into contact with the surface of the piezoelectric sheet, the piezoelectric layer may be soiled or scratched. In particular, when the FPC comes into contact with the portion (active portion) facing the pressure chamber of the piezoelectric layer, the deformation of the piezoelectric sheet when the piezoelectric actuator is driven is inhibited, and as a result, the ink ejection characteristics from the nozzles are reduced. There is a risk of causing an effect. In particular, as described in Patent Document 1, an electric field is generated in the uppermost piezoelectric sheet and contracted in the horizontal direction of the piezoelectric sheet, thereby joining the piezoelectric sheet and the lower surface of the piezoelectric sheet. In a piezoelectric actuator using so-called unimorph deformation that deforms a piezoelectric sheet that operates as a vibration plate in its thickness direction, the active portion is close to the surface of the piezoelectric sheet, so that when the FPC contacts the piezoelectric sheet, the piezoelectric sheet The variation of the deformation amount of the is large.

  An object of the present invention is to provide a piezoelectric actuator capable of preventing a wiring member from coming into contact with a piezoelectric layer, a manufacturing method thereof, a liquid transfer device including such a piezoelectric actuator, and a manufacturing method thereof. It is to be.

According to a first aspect of the present invention, there is provided a method of manufacturing a piezoelectric actuator unit, comprising: a piezoelectric layer having a plurality of active portions; and driving the active portion by generating an electric field in the plurality of active portions. And a flexible wiring member having a linear expansion coefficient larger than that of the piezoelectric layer, the wiring layer being disposed so as to face the piezoelectric layer and having a plurality of wirings connected to the plurality of electrodes. A plurality of first connection terminals respectively connected to the plurality of electrodes are formed on a surface of the piezoelectric layer facing the flexible wiring member, and the piezoelectric layer of the flexible wiring member is connected to the piezoelectric layer. A plurality of second connection terminals respectively connected to the plurality of wirings are formed on a portion facing the plurality of first connection terminals on the facing surface. A plurality of second connection terminals, each of which is a method for manufacturing a piezoelectric actuator unit connected via a bump, wherein one of the plurality of first connection terminals and the plurality of second connection terminals, A bump forming step for forming a bump, and a portion of the surface of the flexible wiring member opposite to the piezoelectric layer, which is opposite to the plurality of second connection terminals, are individually on the opposite side of the flexible wiring member. A projecting portion forming step for forming a plurality of projecting portions projecting from the surface, and heating the plurality of projecting portions while pressing the projecting portion from the opposite side to the piezoelectric layer through the bumps. A first joining step of electrically connecting the plurality of first connection terminals and the plurality of second connection terminals and joining the piezoelectric layer and the flexible wiring member; It is characterized in that that example.

  According to this, before joining the flexible wiring member to the piezoelectric layer, a plurality of protrusions are formed in the portion facing the second connection terminal on the surface of the flexible wiring member opposite to the piezoelectric layer. When heated while pressing the protrusion from the opposite side of the piezoelectric layer to the piezoelectric layer with a heater, etc., the heater does not directly contact the portion of the flexible wiring member having a high thermal expansion coefficient where the protrusion is not formed. . Therefore, heat transfer from the heater is suppressed as compared with the case where surface contact is made with the flexible wiring member, and expansion of the flexible wiring member due to heat is reduced. For this reason, it is possible to prevent the flexible wiring member from being greatly deformed and to bend toward the piezoelectric layer and to come into contact with the piezoelectric layer when the flexible wiring member expands.

  Moreover, since a space is formed between the pressing surface of the heater and the opposite surface by the protrusion, even if the flexible wiring member is deformed to the heater side, there is a risk that the flexible wiring member contacts the pressing surface of the heater. And is not pushed out to the piezoelectric layer side. This reliably prevents the flexible wiring member from being deformed to the piezoelectric layer side and coming into contact with the piezoelectric layer.

  From the above, when the flexible wiring member comes into contact with the piezoelectric layer, the piezoelectric layer having the active portion is soiled or scratched, and the deformation of the piezoelectric layer is inhibited to inhibit the driving of the piezoelectric actuator unit. Can be prevented.

  On the other hand, since the flexible wiring member is heated while being pressed only at the portion where the protruding portion is formed, a large stress is applied to the plurality of first and second connection terminals and bumps facing the protruding portion, and the flexible wiring member and the flexible wiring member are flexible. The wiring member can be reliably bonded.

  A method for manufacturing a piezoelectric actuator unit according to a second invention is a method for manufacturing a piezoelectric actuator unit according to the first invention, wherein at least the plurality of second connection terminals are formed before the first joining step. An adhesive layer forming step of forming an uncured thermosetting adhesive layer on a surface facing the piezoelectric layer of the flexible wiring member including the formed portion, and in the first joining step, By heating the protrusion while pressing the protrusion from the side opposite to the piezoelectric layer toward the piezoelectric layer, the uncured thermosetting adhesive layer penetrates the bump, and the first connection terminal and the second connection terminal The piezoelectric layer and the flexible wiring member are bonded together by the thermosetting adhesive layer while connecting them.

  An uncured thermosetting adhesive layer is formed on the surface of the flexible wiring member on the piezoelectric layer side, and then the flexible wiring member and the piezoelectric layer are heated by pressing the flexible wiring member against the piezoelectric layer. When joining, if the flexible wiring member expands and bends to the piezoelectric layer side and contacts the piezoelectric layer, the adhesive layer formed on the piezoelectric layer side surface of the flexible wiring member contacts the piezoelectric layer. There is a risk of it. When the heater is released after the first connection step, the flexible wiring member shrinks from the expanded state to return to the original state. However, when the adhesive layer is in contact with the piezoelectric layer, the adhesive layer There is a possibility that the flexible wiring member may not be restored while being in contact with the piezoelectric layer, or may be cured while the adhesive layer remains on the piezoelectric layer even when the flexible wiring member is restored. As a result, the adhesive layer attached to the piezoelectric layer or the flexible wiring member joined to the piezoelectric layer may cause the piezoelectric layer to become dirty or scratched, and the deformation of the piezoelectric layer may be hindered. There is a risk of impeding the drive of the unit.

  However, in the present invention, since the flexible wiring member is largely deformed and is prevented from bending toward the piezoelectric layer side, the flexible wiring member comes into contact with the piezoelectric layer by the uncured thermosetting adhesive layer, Thereafter, when the heater is released, it is possible to prevent the flexible wiring member from being bonded to the piezoelectric layer by the adhesive layer so that the deformation does not return to the original or the adhesive layer remains on the piezoelectric layer.

  A method for manufacturing a piezoelectric actuator unit according to a third aspect of the present invention is a method for manufacturing a piezoelectric actuator unit according to the second aspect of the present invention, wherein, in the protrusion forming step, the plurality of protrusions are connected to the first and second protrusions. The connection terminal is formed in an annular shape having a through hole so as to surround at least a portion corresponding to the tip portion of the bump.

  According to this, when the annular protrusion having a through hole formed at least at a position facing the tip of the bump is pressed toward the piezoelectric layer, the pressing force is concentrated on the portion around the through hole of the protrusion. Because the deformation force is applied, the flexible wiring member is deformed so that the portion surrounding the bump tip corresponding to the through hole is largely pushed out to the piezoelectric layer side, and the thermosetting adhesive layer adhering to this portion is pushed out. The piezoelectric layer and the flexible wiring member are also bonded by the extruded adhesive material. Therefore, the adhesive is thickly bonded at the portion surrounding the portion where the first and second connection terminals and the tip of the bump are electrically connected to the piezoelectric layer and the flexible wiring member. The flexible wiring member is securely joined.

  A method for manufacturing a piezoelectric actuator unit according to a fourth invention is a method for manufacturing a piezoelectric actuator unit according to any one of the first to third inventions, wherein after the first joining step, the flexible wiring member is The method further comprises a second joining step of joining the plate-like body by curing the heat shrink curable adhesive filled in the gaps between the plurality of protrusions on the surface opposite to the piezoelectric layer. To do.

  According to this, when the plate-like body is joined to the opposite side of the piezoelectric layer of the flexible wiring member by curing the heat shrink curable adhesive filled in the gaps between the plurality of protrusions, the adhesive shrinks. When cured, the flexible wiring member is pulled to the opposite side of the base material by the heat shrink curable adhesive, thereby preventing the flexible wiring member from being bent toward the piezoelectric layer and coming into contact with the piezoelectric layer. it can. In addition, since the adhesive is cured while being pulled to the opposite side, the flexible wiring member can be applied to the piezoelectric layer even when an unexpected impact or pressure is applied, such as when an operator is working in a later process. Contact can be prevented.

  In addition, since a plurality of protrusions are interposed between the piezoelectric layer on the opposite side of the flexible wiring member and the plate-like body, and the gap between the flexible wiring member and the plate-like body is increased, the flexible wiring member and the plate-like body are The volume of the heat shrink curable adhesive that is filled in between increases, and the flexible wiring member is greatly pulled by the heat shrink curable adhesive.

  In addition, since a plurality of protrusions are formed on the surface of the substrate opposite to the piezoelectric layer, in the joining process of the plate-like body, the heat shrink curable adhesive is interposed between the protrusions by capillary action. Flowing through the gap. Therefore, the gap between the plurality of protrusions can be reliably filled with the heat shrink curable adhesive, and the flexible wiring member can be reliably pulled.

  A method for manufacturing a piezoelectric actuator unit according to a fifth invention is a method for manufacturing a piezoelectric actuator unit according to the fourth invention, and is opposite to the piezoelectric layer of the flexible wiring member before the second joining step. A frame portion forming step of forming a frame portion having substantially the same height as the plurality of protruding portions on an outer edge portion of a portion of the side surface connected to the piezoelectric layer, and in the second bonding step The plate-like body is bonded to the surface of the flexible wiring member opposite to the piezoelectric layer by curing the heat shrinkable curable adhesive filled in the gaps between the plurality of protruding portions and the frame portion. It is characterized by.

  According to this, when the outer edge portion of the portion to be joined to the piezoelectric layer of the flexible wiring member is pulled to the opposite side of the piezoelectric layer by the heat shrinkable adhesive, the flexible wiring member may be easily peeled off. However, in the present invention, since the frame portion is formed on the outer edge of the portion to be joined to the piezoelectric layer on the surface opposite to the piezoelectric layer of the flexible wiring member, the portion to be joined to the piezoelectric layer of the flexible wiring member There is no thermosetting shrinkable adhesive on the outer edge of the flexible wiring member, and it is possible to prevent peeling of the flexible wiring member as described above.

  A method for manufacturing a piezoelectric actuator unit according to a sixth invention is a method for manufacturing a piezoelectric actuator unit according to the fifth invention, wherein the plurality of projecting portions and the frame portion are made of the same material, Forming the plurality of protrusions and the frame material layer on the entire surface of the flexible wiring member on the opposite side of the piezoelectric layer, and excluding the plurality of protrusions and the frame portion from the layer. The projecting portion forming step and the frame portion forming step are simultaneously performed by removing the portion.

  According to this, since the projecting portion and the frame portion can be formed simultaneously, the manufacturing process of the piezoelectric actuator unit is simplified.

  A manufacturing method of a piezoelectric actuator unit according to a seventh invention is a manufacturing method of a piezoelectric actuator unit according to any one of the first to sixth inventions, wherein the piezoelectric actuator unit is the flexible wiring member of the piezoelectric layer. Further, a diaphragm joined to the surface opposite to the surface is further provided.

  When the piezoelectric actuator unit is a piezoelectric actuator unit that generates an electric field in the active portion and deforms the piezoelectric layer and the diaphragm as a whole by deforming the piezoelectric layer in the surface direction (so-called unimorph deformation). If the flexible wiring member comes into contact with the active portion, the driving of the piezoelectric actuator unit is particularly likely to be hindered.

  However, in the present invention, since the flexible wiring member does not easily contact the active portion, it is possible to prevent the drive characteristics of the piezoelectric actuator unit from being hindered.

According to an eighth aspect of the present invention, there is provided a liquid transfer device manufacturing method comprising: a flow path unit in which a liquid flow path including a pressure chamber is formed; and a piezoelectric actuator that applies pressure to the liquid in the pressure chamber. An actuator is provided in the piezoelectric layer having a plurality of active portions for applying pressure to the liquid in the pressure chamber, and drives the active portions by generating an electric field in the plurality of active portions. And a flexible wiring member having a linear expansion coefficient larger than that of the piezoelectric layer, wherein a plurality of wirings are disposed so as to face the piezoelectric layer, and a plurality of wirings connected to the plurality of electrodes are formed. A plurality of first connection terminals respectively connected to the plurality of electrodes are formed on a surface of the piezoelectric layer facing the flexible wiring member, and the flexible wiring A plurality of second connection terminals respectively connected to the plurality of wirings are formed on a surface of the material facing the piezoelectric layer at a portion facing the plurality of first connection terminals. One connection terminal and the plurality of second connection terminals are each a manufacturing method of a liquid transfer device connected via a bump, and any one of the plurality of first connection terminals and the plurality of second connection terminals On the other hand, the bump forming step for forming the bump, and the portion of the flexible wiring member opposite to the piezoelectric layer on the portion facing the plurality of second connection terminals individually, By forming a plurality of protrusions protruding from the opposite surface, and heating the plurality of protrusions while pressing the protrusions from the opposite side to the piezoelectric layer, Above And a first joining step for electrically connecting the plurality of first connection terminals and the plurality of second connection terminals via an amplifier, and joining the piezoelectric layer and the flexible wiring member. It is characterized by.

A piezoelectric actuator unit according to a ninth aspect of the present invention is a piezoelectric layer having a plurality of active portions and a plurality of active portions provided on the piezoelectric layer for driving the active portions by generating an electric field in the plurality of active portions. An electrode and a flexible wiring member that is disposed to face the piezoelectric layer and has a plurality of wirings connected to the plurality of electrodes and having a larger linear expansion coefficient than the piezoelectric layer. A plurality of first connection terminals respectively connected to the plurality of electrodes are formed on a surface of the piezoelectric layer facing the flexible wiring member, and a surface of the flexible wiring member facing the piezoelectric layer is formed. Are formed with a plurality of second connection terminals respectively connected to the plurality of wirings at a portion facing the plurality of first connection terminals, and the plurality of first connection terminals and the plurality of first connection terminals. And connection terminals, respectively, are connected via a bump, the at the surface opposite to the piezoelectric layer of the flexible wiring member, individually to said plurality of second connecting terminals and the opposing portions, the flexible wiring member A plurality of projecting portions projecting from the opposite surface are formed.

A liquid transfer device according to a tenth aspect of the present invention includes a flow path unit in which a liquid transfer flow path for transferring a liquid including a pressure chamber is formed, and a plurality of active portions that apply pressure to the liquid in the pressure chamber. A piezoelectric layer, a plurality of electrodes provided on the piezoelectric layer, for driving the active portion by generating an electric field in the plurality of active portions, and disposed to face the piezoelectric layer, A plurality of wirings connected to a plurality of electrodes, a flexible wiring member having a larger coefficient of linear expansion than the piezoelectric layer, and a surface of the piezoelectric layer facing the flexible wiring member, A plurality of first connection terminals respectively connected to a plurality of electrodes are formed, and a plurality of the plurality of first connection terminals that are opposed to the plurality of first connection terminals are formed on a surface of the flexible wiring member facing the piezoelectric layer. Arrangement of A plurality of second connection terminals connected to each other, and the plurality of first connection terminals and the plurality of second connection terminals are connected via bumps, respectively, and the flexible wiring member A plurality of projecting portions projecting from the opposite surface of the flexible wiring member are individually formed on a portion of the surface opposite to the piezoelectric layer facing the plurality of second connection terminals. It is a feature.

  According to the present invention, before the flexible wiring member is joined to the piezoelectric layer, the plurality of protrusions are formed in the portion facing the second connection terminal on the surface of the flexible wiring member opposite to the piezoelectric layer. When the protrusion is heated while pressing the protrusion from the opposite side of the piezoelectric layer to the piezoelectric layer during bonding, the heater or the like is directly applied to the portion where the protrusion of the flexible wiring member having a high thermal expansion coefficient is not formed. Do not touch. Therefore, heat transfer from the heater is suppressed as compared with the case where surface contact is made with the flexible wiring member, and expansion of the flexible wiring member due to heat is reduced. For this reason, it is possible to prevent the flexible wiring member from being greatly deformed and to bend toward the piezoelectric layer and to come into contact with the piezoelectric layer when the flexible wiring member expands.

  Moreover, since a space is formed between the pressing surface of the heater and the opposite surface by the protrusion, even if the flexible wiring member is deformed to the heater side, there is a risk that the flexible wiring member contacts the pressing surface of the heater. And is not pushed out to the piezoelectric layer side. This reliably prevents the flexible wiring member from being deformed to the piezoelectric layer side and coming into contact with the piezoelectric layer.

  From the above, when the flexible wiring member comes into contact with the piezoelectric layer, the piezoelectric layer is soiled or scratched, and the deformation of the piezoelectric layer is inhibited, and the driving of the piezoelectric actuator is inhibited. Can be prevented.

  On the other hand, since the flexible wiring member is heated while being pressed only at the portion where the protruding portion is formed, a large stress is applied to the plurality of first and second connection terminals and bumps facing the protruding portion, and the flexible wiring member and the flexible wiring member are flexible. The wiring member can be reliably bonded.

  Hereinafter, preferred embodiments of the present invention will be described.

  FIG. 1 is a schematic configuration diagram of a printer 1 as a droplet transfer device having a piezoelectric actuator according to the present embodiment. The printer 1 may be applied to a single printer device, or may be applied to a multi-function printer device having a plurality of functions such as a facsimile function and a copy function. As shown in FIG. 1, the printer 1 includes a carriage 2, an inkjet head 3 (liquid transfer device), a paper transport roller 4, and the like in the apparatus main body. In the following description, the direction in which the liquid is ejected from the nozzle is the downward direction, and the opposite direction is the upward direction. Moreover, when determining the direction in a figure as needed, description is provided suitably.

  The carriage 2 is a substantially box-shaped resin case whose upper surface is opened. The carriage 2 is movably mounted on a guide shaft 5 extending in the left-right direction (scanning direction) in FIG. It is configured to reciprocate in the left-right direction). In the apparatus main body, replaceable ink cartridges (not shown) for supplying a plurality of types of ink (for example, four types of black, yellow, cyan, and magenta) are left standing. It is connected to an ink jet head 3 mounted in the carriage 2 via an ink tube (not shown). Further, a sheet conveying roller 4 and a platen 6 are arranged facing the lower side of the carriage 2, and the recording sheet P is conveyed in the forward direction (paper feeding direction) in FIG. The ink jet head 3 is disposed on the lower surface of the carriage 2, and a plurality of nozzles are mounted on the surface of the carriage 2 so as to be exposed.

  In the printer 1, printing is performed on the recording paper P by ejecting ink from the inkjet head 3 that reciprocates in the scanning direction together with the carriage 2 onto the recording paper P that is transported in the paper feeding direction by the paper transporting roller 4. Do.

  Next, the inkjet head 3 will be described. FIG. 2 is a perspective view showing the configuration of the inkjet head 3 of FIG. FIG. 3 is a plan view of the inkjet head 3. FIG. 4A is a partially enlarged view of FIG. FIGS. 4B to 4D are views showing the surfaces of a diaphragm 40 and piezoelectric layers 41 and 42, which will be described later, in FIG. FIG. 5 is a cross-sectional view taken along line VV in FIG. 6 is a cross-sectional view taken along line VI-VI in FIG.

  For easy understanding of the drawing, FIG. 2 shows a land 52 and a wiring 53 (described later) in a transparent state. 3 and FIG. 4, illustration of a part of the ink flow path of the flow path unit 31 described later is omitted, and illustration of the lower electrode 43 and the intermediate electrode 44 of the piezoelectric actuator 32 is omitted in FIG. ing. In FIG. 4A, the lower electrode 43 and the intermediate electrode 44, both of which are to be illustrated by dotted lines, are illustrated by two-dot chain lines and one-dot chain lines, respectively. 4B to 4D show the positional relationship between the pressure chamber 10 and a lower electrode 43, an intermediate electrode 44, and an upper electrode 45, which will be described later, in a plan view, and the electrodes 43, 44, 45 is hatched.

  As shown in FIGS. 2 to 6, the inkjet head 3 is disposed on the upper surface of the flow path unit 31 in which a plurality of ink flow paths such as a plurality of nozzles 15 and a plurality of pressure chambers 10 are formed, and the flow path unit 31. And a piezoelectric actuator unit 33 that applies pressure for discharging from the nozzle 16 to the ink filled in the pressure chamber 10. The piezoelectric actuator unit 33 includes a flow path unit 31 including a piezoelectric actuator 32 and a COF 50 (Chip On Film) (wiring member) electrically and mechanically connected on the upper surface thereof. The flow path unit 31 includes a plurality of through holes serving as ink flow paths. A plurality of formed plates 21 to 24 are stacked on each other, whereby the manifold channel 11 to which ink is supplied from the ink supply port 9 and the outlet from the manifold channel 11 to the pressure chamber 10 through the channel 12. In addition, an ink flow path (liquid transfer flow path) having a plurality of individual ink flow paths from the pressure chamber 10 to the nozzles 15 through the flow paths 13 and 14 is formed. As will be described later, when pressure is applied to the ink in the pressure chamber 10 by the piezoelectric actuator 32, ink is ejected from the nozzle 15 communicating with the pressure chamber 10. The three plates 21 to 23 excluding the nozzle plate 24 are made of a metal material such as a stainless steel plate or a nickel alloy steel plate, and the nozzle plate 24 is made of a synthetic resin material such as polyimide.

  A plurality of pressure chambers 10 are formed through the plate thickness corresponding to the plurality of nozzles 15 in the uppermost plate 21 of the flow path unit 31, and the pressure chambers 10 are arranged in the scanning direction (left-right direction in FIG. 3). Is formed in such a manner that one end thereof communicates with the flow path 12 and the other end communicates with the nozzle 15. One pressure chamber row 8 is arranged along the paper feeding direction (vertical direction in FIG. 3), and one such pressure chamber row 8 is arranged in two rows in the scanning direction. A pressure chamber group 7 is configured. Further, five such pressure chamber groups 7 are arranged along the scanning direction. Here, the pressure chambers 10 constituting the two pressure chamber rows 8 included in one pressure chamber group 7 are arranged so as to be shifted from each other in the paper feeding direction. In addition, a plurality of nozzles 15 communicating with one end in the longitudinal direction of the plurality of pressure chambers 10 are formed in the lowermost nozzle plate 24 of the flow path unit 31 so as to open downward and penetrate therethrough. Similarly to the pressure chambers 10, the nozzles are arranged in the feed direction, form a nozzle row group, and form five nozzle row groups in the scanning direction.

  Then, among the five pressure chamber groups 7, black ink that is frequently used is ejected from the nozzles 15 corresponding to the pressure chambers 10 constituting the two on the right side in FIG. 3, and the three pressures on the left side in FIG. From the nozzles 15 corresponding to the pressure chambers 10 of the chamber group 7, yellow, cyan, and magenta inks are ejected in order from the nozzles arranged on the right side of FIG. Further, the plate 22 is formed with through holes to be the flow paths 12 and 13 at positions overlapping with both ends in the longitudinal direction of the pressure chamber 10 in plan view, and the plate 23 is a through hole to be the manifold flow path 11. Extends in the paper feeding direction corresponding to the row of pressure chambers 10, and extends to a position where it overlaps the longitudinal direction of the pressure chambers 10 in plan view and communicates with the ink supply port 9.

  Next, the piezoelectric actuator 32 includes a vibration plate 40, piezoelectric layers 41 and 42, a lower electrode 43, an intermediate electrode 44, an upper electrode 45, a conductive bump 46 and a COF 50. The diaphragm 40 is made of a piezoelectric material mainly composed of lead zirconate titanate, which is a mixed crystal of lead titanate and lead zirconate, and is formed on the upper surface of the flow path unit 31 so as to cover the plurality of pressure chambers 10. Is arranged. The thickness of the diaphragm 40 is about 20 μm. The diaphragm 40 does not necessarily need to be made of a piezoelectric material. The piezoelectric layers 41 and 42 are made of the same piezoelectric material as that of the vibration plate 40 and are stacked on each other and disposed on the upper surface of the vibration plate 40. The thicknesses of the piezoelectric layers 41 and 42 are each about 20 μm.

  The lower electrode 43 is arranged between the diaphragm 40 and the piezoelectric layer 41, and corresponds to each pressure chamber group 7 as shown in FIG. It extends in the paper feed direction along the pressure chamber row 8 and faces the plurality of pressure chambers 10 constituting the two pressure chamber rows 8 so as to overlap in plan view. Although not shown, the portions extending in the paper feeding direction corresponding to each pressure chamber group 7 are connected to each other, and a connection terminal (not shown) is provided. The connection terminal is connected to a land of a wiring (not shown) on the COF 50, and the lower electrode 43 is always held at the ground potential via the wiring.

  The intermediate electrode 44 is disposed between the piezoelectric layer 41 and the piezoelectric layer 42, and each of the pressure chamber groups 7 has a plurality of facing portions 44a and connection portions 44b and 44c as shown in FIG. 4C. have. The plurality of facing portions 44a have a substantially rectangular planar shape whose length in the paper feeding direction is shorter than that of the pressure chamber 10, and is disposed so as to face a substantially central portion in the paper feeding direction of the plurality of pressure chambers 10. Has been.

  The connecting portion 44b extends in the paper feeding direction, and among the two pressure chamber rows 8 constituting each pressure chamber group 7, a plurality of pressure chambers 10 constituting the pressure chamber row 8 arranged on the right side in FIG. 4 are connected to each other on the right side in FIG. 4. The connecting portion 44c extends in the paper feeding direction, and among the two pressure chamber rows 8 constituting each pressure chamber group 7, a plurality of pressure chambers 10 constituting the pressure chamber row 8 arranged on the left side in FIG. 4 are connected to each other on the left side in FIG. The intermediate electrode 44 is connected to a connection terminal (not shown) and a land of the intermediate electrode wiring on the COF 50, and is always held at a predetermined positive potential (for example, about 20 V) via the wiring. .

  As shown in FIGS. 3 and 4D, the plurality of upper electrodes 45 are formed on the upper surface of the piezoelectric layer 42 (opposite surface to the COF 50) so as to correspond to the plurality of pressure chambers 10. Are arranged in the paper feed direction, form an upper electrode row group, and constitute an upper electrode row group of two upper electrode 45 included in one upper electrode row group in the scanning direction. The electrodes 45 are displaced from each other with respect to the paper feeding direction. The upper electrode 45 has a substantially rectangular planar shape whose length in the paper feed direction is longer than the facing portion 44 a of the intermediate electrode 44. The upper electrode 45 has a portion at the end opposite to the nozzle 15 in the scanning direction extending to a portion not facing the pressure chamber 10 in the scanning direction, and this portion is a connection terminal connected to the land 52 of the wiring 53 of the COF 50. 45a (first connection terminal). The connection terminal 45a is made of an Ag—Pd material. Furthermore, a conductive bump 46 made of a conductive material such as metal (Ag paste in this embodiment) and projecting upward from the surface of the connection terminal 45a is formed on the surface of the connection terminal 45a. Further, as will be described later, the upper electrode 45 is connected to the wiring 53 on the COF 50 via the conductive bump 46 and is connected to the driver IC 54 mounted with the COF 50, and the ground potential and the predetermined potential (for example, 20V), and the potential is switched. Note that the connection terminals (not shown) of the intermediate electrode 44 and the lower electrode 43 described above are also electrically connected to the wiring via the conductive bumps, like the upper electrode 43.

  In addition, the piezoelectric layer 42 described above is polarized in an upward direction in advance between the upper electrode 45 and the intermediate electrode 44, and the piezoelectric layers 41 and 42 are sandwiched between the upper electrode 45 and the lower electrode 43. The portion is polarized downward from the upper electrode 45 toward the lower electrode 43. A portion of the piezoelectric layer 41 sandwiched between the intermediate electrode 44 and the lower electrode 43 is polarized downward from the intermediate electrode 44 toward the lower electrode 43.

  Next, the COF 50 (flexible wiring member) that applies a potential to the piezoelectric actuator 32 includes a base 51, a plurality of lands 52, a plurality of wirings 53 and 53 z, and a driver IC 54. The COF 50 is arranged and connected above the piezoelectric actuator 32 and is drawn out in the scanning direction.

  The base material 51 is made of a resin material such as polyimide and has a strip shape having insulation and flexibility, and has a linear expansion coefficient larger than that of the piezoelectric material. The wiring 53 is formed of a conductive material such as copper on the base material 51 by printing or the like. The base material 51 is disposed on the piezoelectric actuator 32 with the surface on which the wiring 53 is formed facing the piezoelectric layer 42. Yes. The driver IC 54 incorporates a drive circuit for supplying a drive signal to be applied to the piezoelectric actuator 32, and is arranged on the upper surface of the portion where the COF 50 is drawn. The driver IC 54 is connected to an input wiring 53z for inputting a driving signal from the printer on the main body side and an output wiring 53 for outputting a driving signal from the driver IC 54 to each electrode 43.

  The land 52 (second connection terminal) is disposed in a portion overlapping the connection terminal 45 a in a plan view of the surface (lower surface) facing the piezoelectric layer 42 of the base material 51, and conductive bumps are connected when the piezoelectric actuator 32 and the COF 50 are connected. It contacts with 46 and becomes an electrical connection point. The land 52 is provided at the end of a plurality of output wirings 53 extending from the driver IC 54 and is connected to the driver IC 54. Although not shown, wiring and lands connected to the intermediate electrode 44 and the lower electrode 43 are wired to the COF 50 without passing through the driver IC 54. The driver IC 54 formed on the upper surface of the substrate 51 opposite to the piezoelectric layer 42 and the wiring 53 formed on the lower surface of the substrate 51 are connected through a through hole (not shown) formed in the substrate 51. Connected.

  A plurality of protrusions 56 are formed on the upper surface of the substrate 51. The plurality of projecting portions 56 are arranged at portions facing the conductive bumps 46 on the upper surface of the base material 51. That is, the same number of the plurality of protrusions 56 are provided on the upper surface opposite to the wiring surface of the substrate 51 in correspondence with the positions of the plurality of lands 52 (see FIG. 2). The protrusion 56 has a substantially elliptical shape in plan view, and a through hole 56a is formed in a substantially central portion. The through hole 56a includes the upper end (tip portion) of the conductive bump 46 in the plan view, so that the protrusion 56 has a substantially elliptical shape surrounding the upper end of the conductive bump 46 in the plan view. It is a ring. The protrusions 56 have a larger area than the conductive bumps 46 in plan view, and the plurality of protrusions 56 are formed by laminating a plurality of (three in the figure) thin layers made of solder resist or the like. Is formed.

  Further, a frame portion 57 is disposed on the outer edge portion of the upper surface of the substrate 51 facing the piezoelectric layer 41 so as to surround the plurality of protruding portions 56 along the outer edge portion (see FIG. 3). The frame portion 57 is formed by laminating a plurality (three in the figure) of thin layers made of a solder resist or the like, which is the same as the plurality of projecting portions 56.

  Further, the COF 50 is provided with an adhesive layer 55 containing a thermosetting material such as a solder resist covering the land 52 and the wiring 53 while the surface on which the land 52 and the wiring 53 are formed is arranged to face the piezoelectric layer 42. ing. The conductive bumps 46 and the lands 52 on the piezoelectric layer 42 are pressed and heated against the piezoelectric actuator 32 in the bonding step described later, whereby the conductive bumps 46 on the connection terminals 45a of the piezoelectric layer 42 are heated. And the land 52 come into contact with each other and the adhesive layer 55 covers the periphery of the conductive bump 46 and spreads and cures on the connection terminal 45a, whereby the land 52 and the connection terminal 45a are electrically connected via the conductive bump 46. The ink jet head 3 is formed by forming a piezoelectric actuator unit 33 in which the piezoelectric actuator 32 and the COF 50 are joined together.

  Since the adhesive layer 55 is provided with a distance between the piezoelectric layer 42 and the lower surface of the COF 50 at a portion other than the portion where the land 52 and the conductive bump 46 face each other, the adhesive layer 55 is provided between the adhesive layer 55 and the piezoelectric layer 42. Has a space, and the base material 51 and the piezoelectric layer 42 are not joined. The adhesive layer 55 needs to be formed at least in a portion facing the conductive bump 46 and the land 52, and is formed on the entire lower surface of the substrate 51 so as to cover the wiring 53 in order to protect the wiring 53. However, the adhesive layer 55 may not be formed on the entire surface but may be partially provided at a necessary place.

  In the inkjet head 3, a peeling prevention plate 58 (plate-like body) is disposed on the upper surface of the piezoelectric actuator unit 33 and on the upper surface of the base material 51 (COF 50) on which the protruding portion 56 and the frame portion 57 are formed. Since the COF 50 joined to the piezoelectric actuator 32 is easily subjected to mechanical force by an operator such as an operation of mounting the ink jet head 3 in the carriage in a later process, the connection portion with the COF 50 on the outer peripheral edge of the piezoelectric actuator 32 May easily peel off, and the conductive bump 46 and the land 52 may be peeled off to cause electrical disconnection. Therefore, the peeling of the COF 50 is suppressed by bonding the peeling preventing plate 58 of the COF 50 onto the base material 51.

  The peeling prevention plate 58 is in contact with the protruding portion 56 and the frame portion 57, and a gap that is separated from the upper surface of the base material 51 is formed at a portion that does not face the protruding portion 56 and the frame portion 57. The peeling prevention plate 58 and the base material 51 are joined by an adhesive 59 filled in a gap between the peeling prevention plate 58 and the base material 51. The adhesive 59 is a general-purpose adhesive including a material that shrinks and cures when heated, such as a cyanoacrylic adhesive, and is heated in the manufacturing process of the inkjet head 3 to be described later. Thus, the portion of the COF 50 that is in contact with the adhesive is cured in a state in which the adhesive is contracted and hardened while being pulled upward. As a result, the COF 50 bends toward the piezoelectric layer 42 and comes into contact with the upper surface of the piezoelectric layer 42 to damage the piezoelectric layer 42, or the driving of the piezoelectric actuator 32 when the piezoelectric actuator 32 is driven, as will be described later. Is prevented. Even when an unexpected impact or pressing force is applied to the inkjet head 3 in a later process such as when the inkjet head 3 is mounted on the carriage 2, the space between the piezoelectric layer 42 and the base material 51 remains. Since it is wide, it can prevent coming into contact with the piezoelectric layer 42.

  Here, the operation of the piezoelectric actuator 32 will be described. First, in the standby state before the piezoelectric actuator 32 performs the operation of ejecting ink, as described above, the lower electrode 43 and the intermediate electrode 44 are always set to the ground potential and the predetermined potential (for example, 20 V), respectively. In addition to being held, the potential of the upper electrode 45 is previously held at the ground potential. In this state, the upper electrode 45 has a lower potential than the intermediate electrode 44 and has the same potential as the lower electrode 43.

  As a result, a potential difference is generated between the upper electrode 45 and the intermediate electrode 44, and an upward electric field that is the same as the polarization direction is generated in a portion sandwiched between these electrodes of the piezoelectric layer 42. This portion contracts in the horizontal direction perpendicular to the electric field. As a result, so-called unimorph deformation occurs, and the piezoelectric layers 41 and 42 and the portion (active part) of the diaphragm 40 facing the pressure chamber 10 are deformed so as to protrude toward the pressure chamber 10 as a whole. In this state, the volume of the pressure chamber 10 is smaller than when the piezoelectric layers 41 and 42 and the diaphragm 40 are not deformed.

  When the piezoelectric actuator 32 is driven to eject ink, the potential of the upper electrode 45 is once switched to the predetermined potential and then returned to the ground potential. When the potential of the upper electrode 45 is switched to the predetermined potential, the upper electrode 45 becomes the same potential as the intermediate electrode 44 and at a higher potential than the lower electrode 43. Thereby, the contraction of the piezoelectric layer 42 is restored. At the same time, a potential difference is generated between the upper electrode 45 and the lower electrode 43, and a downward electric field that is the same as the polarization direction is generated in the portion sandwiched between these electrodes of the piezoelectric layers 41 and 42. This portion of 41, 42 contracts in the horizontal direction. Thereby, the portions of the piezoelectric layers 41 and 42 and the diaphragm 40 facing the pressure chamber 10 as a whole are deformed so as to protrude toward the opposite side of the pressure chamber 10, and the volume of the pressure chamber 10 increases. As a result, the pressure of the ink in the pressure chamber 10 decreases, and the ink flows from the manifold channel 11 into the pressure chamber 10.

  Thereafter, when the potential of the upper electrode 45 is returned to the ground potential, the portions facing the pressure chambers 10 of the piezoelectric layers 41 and 42 and the diaphragm 40 become convex toward the pressure chamber 10 as a whole as described above. The volume of the pressure chamber 10 becomes small. As a result, the pressure of the ink in the pressure chamber 10 rises, and the ink is ejected from the nozzle 15 communicating with the pressure chamber 10.

  Further, when the piezoelectric actuator 32 is driven as described above, when the potential of the upper electrode 45 is switched from the ground potential to a predetermined potential, the portion of the piezoelectric layer 42 sandwiched between the upper electrode 45 and the intermediate electrode 44 is Since the portion sandwiched between the upper electrode 45 and the lower electrode 43 of the piezoelectric layers 41 and 42 contracts simultaneously with the expansion from the contracted state to the state before contraction, the above-described expansion of the piezoelectric layer 42 42 is partly absorbed by the above contraction.

  On the other hand, when the potential of the upper electrode 45 is returned from the predetermined potential to the ground potential, the portion sandwiched between the upper electrode 45 and the intermediate electrode 44 of the piezoelectric layer 42 contracts and the upper electrode 45 of the piezoelectric layers 41 and 42 contracts. The portion sandwiched between the piezoelectric layer 42 and the lower electrode 43 expands to a state before contraction, so that the contraction of the piezoelectric layer 42 is partially absorbed by the expansion of the piezoelectric layers 41 and 42.

  From the above, the deformation of the portion of the piezoelectric layers 41, 42 facing the pressure chamber 10 is transmitted to the portion facing the other pressure chamber 10 and the ink from the nozzle 15 communicating with the other pressure chamber 10 is transferred. So-called crosstalk, in which the ejection characteristics fluctuate, is suppressed.

  Note that a potential difference is always generated in the portion between the intermediate electrode 44 and the lower electrode 43 of the piezoelectric layer 41 during the standby state and while the piezoelectric actuator 32 is being driven. Has an electric field in the same direction as the polarization direction. Thereby, this portion of the piezoelectric layer 41 is always contracted. The configuration and driving method of the actuator can be applied to the present invention as long as the pressure for discharging the ink filled in the pressure chamber from the nozzle can be applied.

  Next, a method for manufacturing the inkjet head 3 will be described. FIG. 7 is a process diagram showing the manufacturing process of the inkjet head 3. In FIG. 7, in order to make the drawing easier to understand, the length in the left-right direction with respect to the length in the up-down direction is reduced.

  In order to manufacture the inkjet head 3, first, as shown in FIG. 7A, the diaphragm 40, the piezoelectric layers 41 and 42, the electrodes 43 to 45, and the flow path unit 31 (not shown) prepared in advance are prepared. Conductive bumps 46 are formed by printing or the like on the surface of the connection terminal 45a of the upper electrode 45 in the laminate (bump formation step).

  Further, in a step different from the step of forming the conductive bumps 46 as shown in FIG. 7A, as shown in FIG. 7B, lands 52 and wirings 53 are printed on the base material 51 in advance. A layer 60 (solder resist layer) is formed by laminating a plurality (three in the figure) of thin layers of an insulating material such as a solder resist over almost the entire upper surface of the COF 50 opposite to the surface on which the wiring 53 is formed. Next, as shown in FIG. 7C, the solder resist layer 60 includes a portion surrounding the upper end portion of the conductive bump 46 in a portion facing the land 52 by etching or the like. The protrusion 56 in which the through hole 56a is formed is formed (protrusion forming step). At this time, the frame portion 57 can be simultaneously formed by removing the portion other than the outer edge portion of the solder resist layer 60 facing the piezoelectric layer 42 by etching or the like (frame portion formation). Process). The manufacturing process of the inkjet head 3 is simplified. Subsequently, as shown in FIG. 7 (d), an insulating thermosetting resin such as a liquid solder resist is applied to the lower surface of the substrate 51, and is heated to a semi-cured state. A cured adhesive layer 55 is formed (adhesive layer forming step).

  Then, next, as shown in FIG. 7E, the COF 50 and the piezoelectric layer 42 are aligned so that the land 52 and the conductive bump 46 face each other, and then the protrusion 56 is applied by the heater H. Is heated while being pressed toward the piezoelectric layer 42. Then, the conductive bump 46 penetrates through the uncured adhesive layer 55 and comes into contact with the land 52, and the adhesive layer 55 pushed out by the conductive bump 46 flows out to a portion around the conductive bump 46 and is connected. It reaches the upper surface of the terminal 45a, and the adhesive layer 55 is heated and cured in this state. Thereby, the conductive bump 46 and the land 52 are electrically connected, and the base material 51 and the piezoelectric layer 42 are bonded via the adhesive layer 55 (first bonding step). The heating temperature of the heater H is a temperature for curing the thermosetting adhesive layer.

  Here, when the protrusion 56 is not formed on the upper surface of the base material 51 and the heater H directly contacts the upper surface of the base material 51, the base material 51 is more than the piezoelectric material forming the piezoelectric layers 41 and 42. Since the substrate 51 is formed by a material having a large linear expansion coefficient, when the substrate H is pressed and heated by the heater H, the substrate 51 expands and the land 52 and the conductive bump 46 are connected. There is a possibility that a portion located between the bumps 46 is bent toward the piezoelectric layer 42 and comes into contact with the upper surface of the piezoelectric layer 42. Further, if the uncured adhesive layer 55 applied to the lower surface of the base material 51 is cured in contact with the upper surface of the piezoelectric layer 42, the bent portion of the base material 51 becomes the upper surface of the piezoelectric layer 42. Even if the heating by the heater H is stopped, the expanded base material 51 may not be contracted and deformed and may not be restored. Even when the deformation of the substrate 51 is restored, the adhesive layer 55 may remain on the upper surface of the piezoelectric layer 42.

  If the substrate 51 comes into contact with the piezoelectric layer 42 and is further bonded to the piezoelectric layer 42 or the adhesive layer 55 remains on the upper surface of the piezoelectric layer 42, the piezoelectric layer 42 is soiled or scratched. There is a risk that it will occur. In particular, when the base material 51 comes into contact with the portion (active part) facing the pressure chamber 10 of the piezoelectric layer 42 and is further bonded or the adhesive layer 55 remains, the above-described case is described. As described above, when the piezoelectric actuator 32 is driven, deformation of the vibration plate 40 and the piezoelectric layers 41 and 42 may be inhibited, and ink ejection drive from the nozzle 15 (drive of the piezoelectric actuator 32) may be obstructed. In particular, in the piezoelectric actuator 32 in which the diaphragm 40 and the piezoelectric layers 41 and 42 are unimorph-deformed as described above, the inhibition of the ink ejection drive from the nozzle 15 is significant.

  However, in the present embodiment, the protruding portion 56 is formed on the upper surface of the substrate 51, and when the protruding portion 56 is pressed toward the piezoelectric layer 42 by the heater H, the heater H comes into contact with the protruding portion 56 and the base Since the material 51 is not in direct contact, it is difficult for heat to be applied to the base material 51, and the deformation amount of the base material 51 can be reduced. This prevents the base material 51 from coming into contact with the piezoelectric layer 42.

  Moreover, since the protrusion 56 is formed on the upper surface of the base material 51, a gap is formed between the heater H and the base material 51. Therefore, even if the base material 51 bends to the heater H side, the base material 51. Is difficult to contact the heater H. Accordingly, the heater H is prevented from being pressed downward by the heater H except for the portion bonded to the piezoelectric layer 42 and coming into contact with the piezoelectric layer 42.

  And since it prevents that the base material 51 contacts the piezoelectric layer 42, it is also prevented that the adhesive bond layer 55 formed in the lower surface of the base material 51 contacts the upper surface of the piezoelectric layer 42, thereby. When the heater H is released, the adhesive layer 55 is cured and the base material 51 is bonded to the piezoelectric layer 42, or the adhesive layer 55 remains on the upper surface of the piezoelectric layer 42. Is prevented.

  From the above, the base material 51 is prevented from coming into contact with the piezoelectric layer 42 and further bonded to the piezoelectric layer 42 or the adhesive layer 55 remaining on the piezoelectric layer 42. Dirt and scratches will not occur. In particular, in the portion (active portion) facing the pressure chamber 10 of the piezoelectric layer 42, the base material 51 and the adhesive layer 55 can be prevented from contacting or remaining as described above, so that the piezoelectric actuator 32 is driven. In this case, the deformation of the vibration plate 40 and the piezoelectric layers 41 and 42 at this time is inhibited, and it is possible to prevent the ink ejection drive from the nozzle 15 (drive of the piezoelectric actuator 32) from being inhibited.

  On the other hand, since heat is sufficiently applied to the portions of the substrate 51 facing the conductive bumps 46 and the lands 52 through the protrusions 56, the adhesive layer 55 in this portion is surely cured, and the conductive bumps. 46 and the land 52 are reliably electrically connected, and the COF 50 and the piezoelectric layer 42 are reliably bonded.

  Moreover, since the protrusion part 56 is cyclic | annular, among the parts facing the conductive bump 46 and the land 52, the part surrounding the upper end part of the conductive bump 46 is pressed most strongly. Become. Therefore, as shown in FIG. 8, in the base material 51, a portion surrounding the upper end portion of the conductive bump 46 is deformed toward the piezoelectric layer 42, and the surrounding portion of the adhesive layer 55 is pushed out by this deformation.

  As a result, in addition to the adhesive layer 55 pushed out when the conductive bump 46 penetrates, the adhesive layer 55 pushed out by the base material 51 also flows out to the peripheral portion of the conductive bump 46 to the connection terminal 45a. Reach. As a result, the piezoelectric layer 42 and the base material 51 are thickened at the portion surrounding the portion facing the conductive bump 46 and the land 52, so that the piezoelectric layer 42 and the base material 51 are reliably bonded when cured. Is done. Here, FIG. 8 is an enlarged view of the vicinity of the conductive bump 46 of FIG. The conductive bump 46 is made of Ag paste, and is in contact with the land 52 in a state where the upper end is slightly crushed by the elastic force, so that the force concentrates on the upper end. By adding, the contact state can be improved.

  Next, as illustrated in FIG. 7F, an adhesive 59 is filled on the upper surface of the base material 51 so as to fill the gaps between the plurality of protrusions 56. Then, as shown in FIG. 7G, a peeling prevention plate 58 is disposed on the upper surface of the base material 51 filled with the adhesive 59, and the peeling prevention plate 58 is moved downward toward the base material 51 by the heater H. The adhesive 59 is cured by pressing and the base material 51 and the peeling prevention plate 58 are joined (second joining step).

  At this time, since the adhesive 59 is contracted and cured by being heated, the base material 51 is lifted upward in a direction away from the piezoelectric layer 42 by the contraction of the adhesive 59. This prevents the base material 51 from being deformed downward and coming into contact with the piezoelectric layer 42 by heating when the adhesive 59 is cured. Further, since the base material 51 is lifted upward in the direction away from the piezoelectric layer 42, an unexpected impact such as when the inkjet head 3 provided with the peeling prevention plate 58 is mounted on a carriage in a later process, etc. Even when a pressing force is applied to the ink jet head 3, the space between the piezoelectric layer 42 and the base material 51 is widened, so that it can be prevented from coming into contact with the piezoelectric layer 42.

  Furthermore, since the protrusion part 56 and the frame part 57 are formed in the upper surface of the base material 51, since the clearance gap is made between the base material 51 and the peeling prevention board 58, compared with the case where there is no these. The thickness (volume) of the adhesive 59 is increased. Thereby, when the adhesive 59 contracts, the base material 51 is largely lifted upward, and the base material 51 can be reliably prevented from coming into contact with the piezoelectric layer 42.

  Further, since the plurality of protrusions 56 are provided corresponding to the plurality of lands 52 (the plurality of connection terminals 45a), a plurality of protrusions 56 are formed on the upper surface of the substrate 51 in a row corresponding to the plurality of nozzles 15. Since the portions 56 are scattered, when the adhesive 59 is filled, the adhesive 59 flows through these gaps by the capillary force, and the gaps of the protrusions 56 are surely filled.

  Furthermore, when the adhesive 59 is filled in the outer edge portion of the upper surface of the base material 51 facing the piezoelectric layer 42, this portion of the base material 51 is lifted, and the direction in which the base material 51 is peeled off by this portion is lifted. However, since the frame portion 57 is formed on the outer edge portion of the upper surface of the base material 51 facing the piezoelectric layer 42, the adhesive 59 is not located in this portion, and the bonding is performed. It is possible to prevent the force in the peeling direction from being applied to the base material 51 due to the contraction of the agent 59.

  At this time, since the frame portion 57 is formed, the adhesive 59 can be prevented from flowing out from the upper surface of the base material 51 when the adhesive 59 is filled.

  According to the embodiment described above, the protruding portion 56 is formed on the upper surface of the base material 51, and when the protruding portion 56 is pressed toward the piezoelectric layer 42 by the heater H, the heater H contacts the protruding portion 56. Since the base material 51 is not in direct contact with the base material 51, the partial heat of the base material 51 where the protruding portion 56 is not provided is hardly applied, and the deformation amount of the base material 51 can be reduced. Thereby, it can prevent that the base material 51 contacts the piezoelectric layer 42. FIG.

  Further, since the protrusions 56 are formed on the upper surface of the base material 51, a gap is formed between the heater H and the base material 51. Therefore, even if the base material 51 is bent toward the heater H, the base material 51 Is difficult to contact the heater H. Accordingly, the heater H is prevented from being pressed downward by the heater H except for the portion bonded to the piezoelectric layer 42 and coming into contact with the piezoelectric layer 42.

  And since it prevents that the base material 51 contacts the piezoelectric layer 42, it is also prevented that the adhesive bond layer 55 of the lower surface of the base material 51 contacts the upper surface of the piezoelectric layer 42, thereby. When the heater H is released, the adhesive layer 55 is cured and the base material 51 is bonded to the piezoelectric layer 42, or the adhesive layer 55 remains on the upper surface of the piezoelectric layer 42. Is prevented.

  From the above, the base material 51 is prevented from coming into contact with the piezoelectric layer 42 and further bonded to the piezoelectric layer 42 or the adhesive layer 55 remaining on the piezoelectric layer 42. Can prevent dirt and scratches from occurring. In particular, in the portion (active portion) facing the pressure chamber 10 of the piezoelectric layer 42, the base material 51 and the adhesive layer 55 can be prevented from contacting or remaining as described above, so that the piezoelectric actuator 32 is driven. In this case, the deformation of the vibration plate 40 and the piezoelectric layers 41 and 42 is inhibited, and it is possible to prevent the ink ejection drive from the nozzle 15 (drive characteristics of the piezoelectric actuator 32) from being inhibited.

  On the other hand, since heat is sufficiently applied to the portions of the substrate 51 facing the conductive bumps 46 and the lands 52 through the protrusions 56, the adhesive layer 55 in this portion is surely cured, and the conductive bumps. 46 and the land 52 are reliably electrically connected, and the COF 50 and the piezoelectric layer 42 are reliably bonded.

  Moreover, since the protrusion part 56 is cyclic | annular, among the parts facing the conductive bump 46 and the land 52, the part surrounding the upper end part of the conductive bump 46 is pressed most strongly. Become. Therefore, in the base material 51, a portion surrounding the upper end portion of the conductive bump 46 is deformed to the piezoelectric layer 42 side, and the adhesive layer 55 is pushed out by this deformation. Thereby, in addition to the adhesive layer 55 pushed out by the conductive bump 46, the adhesive layer 55 pushed out by the base material 51 also flows out to the peripheral portion of the conductive bump 46 and reaches the upper surface of the connection terminal 45a. As a result, the piezoelectric layer 42 and the base material 51 are bonded to each other thickly in a portion surrounding the portion facing the conductive bump 46 and the land 52, and the piezoelectric layer 42 and the base material 51 are reliably bonded.

  In addition, since the heat-effect shrinkable adhesive 59 that joins the COF 50 and the peeling prevention plate 58 is heated to shrink and harden, the base material 51 is separated from the piezoelectric layer 42 by the shrinkage of the adhesive 59. Is lifted upwards. This prevents the base material 51 from being deformed downward and coming into contact with the piezoelectric layer 42 by heating when the adhesive 59 is cured.

  Furthermore, since the protrusion part 56 and the frame part 57 are formed in the upper surface of the base material 51, since the clearance gap is made between the base material 51 and the peeling prevention board 58, compared with the case where there is no these. The thickness (volume) of the adhesive 59 is increased. Thereby, when the adhesive 59 contracts, the base material 51 is largely lifted upward, and the base material 51 can be reliably prevented from coming into contact with the piezoelectric layer 42.

  Further, since the plurality of protrusions 56 are scattered on the upper surface of the base material 51, when filling the adhesive 59, the adhesive 59 flows through these gaps by capillary force, and the gaps of the protrusions 56 are surely formed. Buried.

  Furthermore, when the adhesive 59 is filled in the outer edge portion of the upper surface of the base material 51 facing the piezoelectric layer 42, this portion of the base material 51 is lifted, and the direction in which the base material 51 is peeled off by this portion is lifted. However, since the frame portion 57 is formed on the outer edge portion of the upper surface of the base material 51 facing the piezoelectric layer 42, the adhesive 59 is not located in this portion, and the bonding is performed. It is possible to prevent the force in the peeling direction from being applied to the base material 51 due to the contraction of the agent 59.

  At this time, since the frame portion 57 is formed, the adhesive 59 can be prevented from flowing out from the upper surface of the base material 51 when the adhesive 59 is filled.

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

  In the present embodiment, the adhesive layer 55 is formed on almost the entire lower surface of the substrate 51, but the present invention is not limited to this. In one modified example, as shown in FIG. 9D, the adhesive layer 75 is formed only on the portion of the lower surface of the base 51 where the land 52 is formed (Modified Example 1). In the first modification, the step of forming the conductive bump 46 as shown in FIG. 9A, and the protrusion 56 and the frame 57 as shown in FIGS. 9B and 9C are provided. Since the forming process is the same as that of the embodiment, the description thereof is omitted here.

  Also in this case, as in the above-described embodiment, when the protrusions 56 are pressed against the piezoelectric layer 42 by the heater H and heated, the conductive bumps 46 form the adhesive layer as shown in FIG. The adhesive layer 75 pushed through the conductive bump 46 flows out to the peripheral portion of the conductive bump 46 and reaches the upper surface of the piezoelectric layer 42 while passing through 75 and contacting the land 52. In this state, the adhesive layer By curing 55, the conductive bump 46 and the land 52 are electrically connected, and the substrate 51 and the piezoelectric layer 42 are bonded.

  Also in this case, since the protruding portion 56 is formed in the portion facing the conductive bump 46 on the upper surface of the base material 51, when heating is performed by the heater H, the pressure chamber 10 of the base material 51 Since heat is not easily applied to the opposing portions, and a gap is formed between the heater H and the base material 51, even if the base material 51 is bent toward the heater H, the base material 51 is difficult to contact the heater H. It is possible to prevent the base material 51 from coming into contact with the active portion of the piezoelectric layer 42.

  As a result, the base material 51 is prevented from coming into contact with the piezoelectric layer 42 and further bonded to the piezoelectric layer 42 or the adhesive layer 55 remaining on the piezoelectric layer 42. It is possible to prevent the occurrence of scratches or scratches, or the deformation of the vibration plate 40 and the piezoelectric layers 41 and 42 from being hindered to hinder the ejection of ink from the nozzle 15.

  On the other hand, since heat is sufficiently applied to the portions of the substrate 51 facing the conductive bumps 46 and the lands 52 through the protrusions 56, the conductive bumps 46 and the lands 52 are reliably electrically connected. The base material 51 and the piezoelectric layer 42 are reliably bonded.

  Further, in the present embodiment, the base material 51 and the piezoelectric layer 42 are joined in a state where the conductive bump 46 and the land 52 are electrically connected by the adhesive layer 55. However, the present invention is not limited to this. . In another modification, as shown in FIG. 10A, as in the present embodiment, the COF 50 having the wiring 53 formed on the substrate 51 in advance is opposite to the surface on which the wiring 53 is formed. After the solder resist layer 60 is formed on the upper surface, as shown in FIG. 10B, by etching, a portion facing the land 52 (portion facing the conductive bump 46) and a portion of the solder resist layer 60, By removing the portion excluding the outer edge portion of the portion that will face the piezoelectric layer 42, the substantially circular protruding portion 156 and the frame portion in a plan view without the through hole 56 a (see FIG. 5) on the upper surface of the base material 51. 57 (see FIG. 3). In this modification, as shown in FIG. 10A, a solder resist layer 60a covering the wiring 53 is also formed on the lower surface of the base 51 on the wiring 53 side, and etching is performed as shown in FIG. Thus, the land 52 is formed by forming the through hole 60 b exposing a part of the wiring 53. Then, as shown in FIG. 10C, solder 81 (bump) protruding from the lower surface of the base material 51 is formed on the surface of the land 52 in the through hole 60b formed in the lower surface of the base material 51 (bump). Forming step). Next, the substrate 51 on which the solder 81 is formed by the heater H is heated while being pressed toward the piezoelectric layer 42. Then, as shown in FIG. 10 (d), the solder 81 melts and flows onto the upper surface of the connection terminal 45a, and when the heating by the heater H is stopped, the solder 81 is cured in this state, and thus the connection terminal 45a and The land 52 is electrically connected via the solder 81, and the piezoelectric layer 42 and the substrate 51 are joined by the solder 81 (first joining step) (Modification 2).

  Also in this case, since the protruding portion 156 is formed in the portion facing the solder 81 on the upper surface of the base material 51, when heated by the heater H, the portion facing the pressure chamber 10 of the base material 51 is formed. Is difficult to apply heat, and there is a gap between the heater H and the base material 51. Therefore, even if the base material 51 is bent toward the heater H, the base material 51 is difficult to contact the heater H. Contact with the piezoelectric layer 42 can be prevented.

  As a result, the base material 51 is prevented from coming into contact with the piezoelectric layer 42 and further bonded to the piezoelectric layer 42 or the adhesive layer 55 remaining on the piezoelectric layer 42. It is possible to prevent the occurrence of scratches or scratches, or the deformation of the vibration plate 40 and the piezoelectric layers 41 and 42 from being hindered and the ink ejection from the nozzles 15 being hindered.

  On the other hand, since heat is sufficiently applied to the portions of the base material 51 facing the solder 81 and the land 52 via the protrusions 156, the solder 81 and the land 52 are reliably electrically connected and the base material 51 is also connected. And the piezoelectric layer 42 are securely bonded.

  Further, when the base material 51 and the piezoelectric layer 42 are joined by the adhesive layer 55 formed on the lower surface of the base material 51, the protruding portion 56 is not limited to an annular shape, as shown in FIG. A substantially circular protruding portion 156 in a plan view in which a through hole 56a (see FIG. 5) is not formed in a portion facing the land 52 (a portion facing the conductive bump 46) on the upper surface of the substrate 51. May be formed (Modification 3).

  Also in this case, since the protruding portion 156 is formed in the portion facing the conductive bump 46 on the upper surface of the substrate 51, it faces the pressure chamber 10 of the substrate 51 when heated by the heater H. Since heat is not easily applied to the portion and a gap is formed between the heater H and the base material 51, the base material 51 is difficult to contact the heater H even if the base material 51 is bent toward the heater H side. It is possible to prevent 51 from coming into contact with the active portion of the piezoelectric layer 42.

  As a result, the base material 51 is prevented from coming into contact with the piezoelectric layer 42 and further bonded to the piezoelectric layer 42 or the adhesive layer 55 remaining on the piezoelectric layer 42. It is possible to prevent the occurrence of scratches or scratches, or the deformation of the vibration plate 40 and the piezoelectric layers 41 and 42 from being hindered and the ink ejection from the nozzles 15 being hindered.

  On the other hand, since heat is sufficiently applied to the portions of the substrate 51 facing the conductive bumps 46 and the lands 52 through the protrusions 156, the conductive bumps 46 and the lands 52 are reliably electrically connected. The base material 51 and the piezoelectric layer 42 are reliably bonded.

  In this case, when the protrusion 156 is pressed toward the piezoelectric layer 42 by the heater H, only the adhesive layer 55 pushed out by the conductive bump 46 flows out to a portion surrounding the conductive bump 46. It reaches the upper surface of the piezoelectric layer 42, and the adhesive layer 55 joins the piezoelectric layer 42 and the substrate 51.

  In this case, in the process shown in FIGS. 7B and 7C, instead of forming the protrusion 56 and the frame 57, the protrusion 156 and the frame 57 are formed by printing or the like. That's fine.

  In the above-described embodiment, the protruding portion 56 and the frame portion 57 are formed simultaneously. However, the present invention is not limited to this, and the protruding portion 56 and the frame portion 57 may be formed in separate steps. In this case, the protruding portion 56 and the frame portion 57 may be made of different materials. The frame portion 57 may be formed in a concavo-convex shape formed integrally and continuously with the plurality of protrusions 56 along the frame portion 57 and on the nearest outer edge side among the plurality of protrusions 56, In this case, the COF 50 is more difficult to peel off.

  Further, in the present embodiment, after filling the adhesive 59 so as to fill the gaps between the plurality of protrusions 56 and the frame portion 57 on the upper surface of the base material 51, the peeling prevention plate 58 is disposed on the upper surface of the base material 51. The base material 51 and the peeling prevention plate 58 are joined, but the present invention is not limited to this. For example, an uncured adhesive raised above the tip of the protrusion 56 is disposed in a part of the gap between the plurality of protrusions 56 on the upper surface of the substrate 51, and then peeled off on the upper surface of the substrate 51. 58 may be disposed to join the base member 51 and the peeling prevention plate 58 together. In this case, when the peeling prevention plate 58 is pressed toward the base material 51, the portion raised above the protruding portion 56 of the adhesive 59 is crushed, and the adhesive 59 is pushed by the capillary force. It flows through the gap and fills the entire gap of the protrusion 56.

  Further, the frame portion 57 may not be provided. When the frame portion 57 is not provided, the peeling prevention plate 58 is disposed on the upper surface of the base material 51 on which the protruding portion 56 is formed, and then the base portion 51 is peeled off. An adhesive 59 may be filled in the gap with the prevention plate 58. Also in this case, the adhesive 59 flows through the gap between the protrusions 56 by capillary force and fills the entire area of the gap between the protrusions 56. In this case, in the step shown in FIG. 7C, the portion of the layer 60 such as a solder resist that is opposed to the land 52 except for the portion surrounding the upper end portion of the conductive bump 46 is removed. Thus, only the protruding portion 56 may be formed. Further, if the peeling prevention plate is a highly conductive material such as metal, it may also serve as a heat equalizing plate for making the heat distribution in the COF 50 uniform, and crosstalk is caused by vibration when the piezoelectric actuator is driven. You may serve as the function of the vibration suppression board for suppressing that it becomes easy to occur.

  Moreover, in this Embodiment, although the protrusion part 56 was comprised with the soldering resist etc., it is not restricted to this, For example, the protrusion part 56 may be comprised with the metal material etc. When the protruding portion 56 is made of a highly conductive metal material or the like, when the protruding portion 56 is heated against the piezoelectric layer 42 by the heater H, the heat of the heater H causes the protruding portion 56 to be heated. Thus, heat is easily transferred to the land 52 and the adhesive layer 55 in the vicinity of the bump 46, and the COF 50 and the piezoelectric layer 42 can be reliably bonded.

  Further, the protrusion is not limited to being substantially annular in plan view as in the above-described embodiment, or being substantially circular in plan view as in Modifications 2 and 3, The shape of the protruding portion may be another shape, for example, a substantially rectangular shape in plan view.

  In the present embodiment, the piezoelectric actuator 32 applies pressure to the ink in the pressure chamber 10 by so-called unimorph deformation, but is not limited thereto. For example, a plurality of piezoelectric layers polarized in the thickness direction are stacked on the pressure chamber, and by generating an electric field in the thickness direction on these piezoelectric layers, the piezoelectric layer is expanded in the thickness direction, The present invention can also be applied to a piezoelectric actuator that applies pressure to the ink in the pressure chamber 10 by deformation different from unimorph deformation, such as a piezoelectric actuator that applies pressure to the ink in the ink 10.

  In the above description, an example in which the present invention is applied to an ink jet head that discharges ink from a nozzle by applying pressure to ink in a pressure chamber and a piezoelectric actuator used in the ink jet head has been described. However, the present invention can also be applied to a liquid transfer device that discharges or transfers a liquid other than ink, and a piezoelectric actuator used in such a liquid transfer device. The present invention can also be applied to piezoelectric actuators used for purposes other than applying pressure to the liquid in the pressure chamber.

1 is a schematic configuration diagram of a printer according to an embodiment of the present invention. FIG. 2 is a perspective view of the ink jet head of FIG. 1. FIG. 3 is a plan view of FIG. 2. (A) is the elements on larger scale of FIG. 3, (b)-(d) is a figure of the surface of the diaphragm of (a) and each piezoelectric layer. It is the VV sectional view taken on the line of FIG. It is the VI-VI sectional view taken on the line of FIG. It is process drawing which shows the manufacturing process of an inkjet head. It is the elements on larger scale of FIG.7 (d). FIG. 8 is a diagram corresponding to FIG. FIG. 8 is a diagram corresponding to FIG. FIG. 6 is a diagram corresponding to FIG.

Explanation of symbols

32 Piezoelectric actuators 41 and 42 Piezoelectric layer 45 Upper electrode 45a Connection terminal 46 Bump 52 Land 55 Adhesive 50 COF
51 Substrate 56 Projection 57 Frame 75 Adhesive 81 Solder 156 Projection

Claims (10)

A piezoelectric layer having a plurality of active portions;
A plurality of electrodes provided on the piezoelectric layer for driving the active part by generating an electric field in the plurality of active parts;
A flexible wiring member having a linear expansion coefficient larger than that of the piezoelectric layer, wherein a plurality of wirings connected to the plurality of electrodes are formed so as to face the piezoelectric layer;
A plurality of first connection terminals respectively connected to the plurality of electrodes are formed on a surface of the piezoelectric layer facing the flexible wiring member,
On the surface of the flexible wiring member facing the piezoelectric layer, a plurality of second connection terminals respectively connected to the plurality of wirings are formed in portions facing the plurality of first connection terminals,
The plurality of first connection terminals and the plurality of second connection terminals are each a method of manufacturing a piezoelectric actuator unit connected via a bump,
A bump forming step of forming the bump on any one of the plurality of first connection terminals and the plurality of second connection terminals;
A plurality of projecting portions projecting from the opposite surface of the flexible wiring member are individually provided in portions facing the plurality of second connection terminals on the surface of the flexible wiring member opposite to the piezoelectric layer. A protrusion forming step to be formed;
By heating the plurality of protrusions while pressing toward the piezoelectric layer from the side opposite to the piezoelectric layer, the plurality of first connection terminals and the plurality of second connection terminals are interposed via the bumps. A method of manufacturing a piezoelectric actuator unit, comprising: a first joining step of electrically connecting and joining the piezoelectric layer and the flexible wiring member. Prior to the first bonding step, an uncured thermosetting adhesive layer is formed on the surface of the flexible wiring member that includes at least the portion where the plurality of second connection terminals are formed, facing the piezoelectric layer. Further comprising an adhesive layer forming step,
In the first joining step, the bump is heated while being pressed from the side opposite to the piezoelectric layer toward the piezoelectric layer, thereby causing the uncured thermosetting adhesive layer to penetrate through the bump. 2. The method of manufacturing a piezoelectric actuator unit according to claim 1, wherein the piezoelectric layer and the flexible wiring member are joined by the thermosetting adhesive layer while connecting the connection terminal and the second connection terminal. .   In the protruding portion forming step, the plurality of protruding portions are formed in an annular shape in which a through hole is formed so as to surround at least a portion corresponding to the tip portion of the bump provided in the first and second connection terminals. The method of manufacturing a piezoelectric actuator unit according to claim 2.   After the first bonding step, a plate-like body is bonded to the surface of the flexible wiring member opposite to the piezoelectric layer by curing the heat shrink curable adhesive filled in the gaps between the plurality of protrusions. The method for manufacturing a piezoelectric actuator unit according to claim 1, further comprising a second joining step. Before the second bonding step, a frame portion having a height substantially the same as the plurality of projecting portions is formed on an outer edge portion of the surface of the flexible wiring member opposite to the piezoelectric layer, which is connected to the piezoelectric layer. A frame forming step of forming
In the second joining step, the heat shrink curable adhesive filled in the gaps between the plurality of protrusions and the frame portion is cured on the surface of the flexible wiring member opposite to the piezoelectric layer, The method for manufacturing a piezoelectric actuator unit according to claim 4, wherein the plate-like bodies are joined. The plurality of protruding portions and the frame portion are made of the same material,
A layer of material of the plurality of protrusions and the frame portion is formed on the entire surface of the flexible wiring member on the side opposite to the piezoelectric layer, and a portion that becomes the plurality of protrusions and the frame portion from the layer is formed. 6. The method of manufacturing a piezoelectric actuator unit according to claim 5, wherein the protruding portion forming step and the frame portion forming step are simultaneously performed by removing the removed portion.   The piezoelectric actuator according to any one of claims 1 to 6, wherein the piezoelectric actuator unit further includes a diaphragm bonded to a surface of the piezoelectric layer opposite to the flexible wiring member. Unit manufacturing method. A flow path unit in which a liquid flow path including a pressure chamber is formed;
A piezoelectric actuator that applies pressure to the liquid in the pressure chamber;
The piezoelectric actuator is
A piezoelectric layer having a plurality of active portions for applying pressure to the liquid in the pressure chamber;
A plurality of electrodes provided on the piezoelectric layer for driving the active part by generating an electric field in the plurality of active parts;
A flexible wiring member that is disposed so as to face the piezoelectric layer and has a plurality of wirings connected to the plurality of electrodes and having a larger linear expansion coefficient than the piezoelectric layer;
A plurality of first connection terminals respectively connected to the plurality of electrodes are formed on a surface of the piezoelectric layer facing the flexible wiring member,
On the surface of the flexible wiring member facing the piezoelectric layer, a plurality of second connection terminals respectively connected to the plurality of wirings are formed in portions facing the plurality of first connection terminals,
The plurality of first connection terminals and the plurality of second connection terminals are each a manufacturing method of a liquid transfer device connected via a bump,
A bump forming step of forming the bump on any one of the plurality of first connection terminals and the plurality of second connection terminals;
A plurality of projecting portions projecting from the opposite surface of the flexible wiring member are individually provided in portions facing the plurality of second connection terminals on the surface of the flexible wiring member opposite to the piezoelectric layer. A protrusion forming step to be formed;
By heating the plurality of protrusions while pressing toward the piezoelectric layer from the side opposite to the piezoelectric layer, the plurality of first connection terminals and the plurality of second connection terminals are interposed via the bumps. A method for manufacturing a liquid transfer device, comprising: a first joining step of electrically connecting and joining the piezoelectric layer and the flexible wiring member. A piezoelectric layer having a plurality of active portions;
A plurality of electrodes provided on the piezoelectric layer for driving the active part by generating an electric field in the plurality of active parts;
A flexible wiring member that is disposed so as to face the piezoelectric layer and has a plurality of wirings connected to the plurality of electrodes and having a larger linear expansion coefficient than the piezoelectric layer;
A plurality of first connection terminals respectively connected to the plurality of electrodes are formed on a surface of the piezoelectric layer facing the flexible wiring member,
On the surface of the flexible wiring member facing the piezoelectric layer, a plurality of second connection terminals respectively connected to the plurality of wirings are formed in portions facing the plurality of first connection terminals,
The plurality of first connection terminals and the plurality of second connection terminals are connected via bumps, respectively.
A plurality of projecting portions projecting from the opposite surface of the flexible wiring member are individually formed on portions of the surface of the flexible wiring member opposite to the piezoelectric layer facing the plurality of second connection terminals. A piezoelectric actuator unit characterized by comprising: A flow path unit in which a liquid transfer flow path for transferring a liquid including a pressure chamber is formed;
A piezoelectric layer having a plurality of active portions for applying pressure to the liquid in the pressure chamber;
A plurality of electrodes provided on the piezoelectric layer for driving the active part by generating an electric field in the plurality of active parts;
A flexible wiring member that is disposed so as to face the piezoelectric layer and has a plurality of wirings connected to the plurality of electrodes and having a larger linear expansion coefficient than the piezoelectric layer;
A plurality of first connection terminals respectively connected to the plurality of electrodes are formed on a surface of the piezoelectric layer facing the flexible wiring member,
On the surface of the flexible wiring member facing the piezoelectric layer, a plurality of second connection terminals respectively connected to the plurality of wirings are formed in portions facing the plurality of first connection terminals,
The plurality of first connection terminals and the plurality of second connection terminals are connected via bumps, respectively.
A plurality of projecting portions projecting from the opposite surface of the flexible wiring member are individually formed on portions of the surface of the flexible wiring member opposite to the piezoelectric layer facing the plurality of second connection terminals. A liquid transfer device.

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