JP2010227761A - Liquid droplet discharge head, method for manufacturing the same, and liquid droplet discharge device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid droplet discharge head capable of enhancing the connection reliability in an OLB connection part, a method for manufacturing the same, and a liquid droplet discharge device. <P>SOLUTION: The liquid droplet discharge head includes a first substrate 22, a drive element 23 provided on the first substrate 22, the second substrate 25 provided on the side of the drive element 23 of the first substrate 22 and a flexible substrate 27 joined to the terminal part 47 of the drive element 23 exposed to the base of a through-hole 150 through a conductive adhesive material 79 by inserting the connection part 27b provided to one end of the flexible substrate 27 into the through-hole 150 of the second substrate 25. An opening 150 is formed to at least one end part in the width direction of the connection part 27b of the flexible substrate 27 and the conductive adhesive material 79 is arranged to both sides of the connection part 27b through an opening 90. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a droplet discharge head, a method for manufacturing a droplet discharge head, and a droplet discharge apparatus.

  A droplet discharge method (inkjet method) has been proposed as one method for manufacturing a microdevice. This droplet discharge method is a method in which a functional liquid containing a material for forming a device is formed into droplets and discharged from a droplet discharge head. Patent Document 1 below discloses an example of a technique related to a droplet discharge head (inkjet recording head). The droplet discharge head disclosed in Patent Document 1 has a structure in which a driving element (piezoelectric element) is connected to a driving device (driver IC) by wire bonding (for example, Patent Document 1).

  By the way, when manufacturing a microdevice based on the droplet discharge method, in order to meet the demand for further miniaturization of the microdevice, the distance between nozzle openings provided in the droplet discharge head (nozzle pitch) Is desired to be as small (narrow) as possible. Since a plurality of drive elements are provided corresponding to the nozzle openings, if the nozzle pitch is reduced, the distance between the drive elements needs to be reduced (shortened) corresponding to the nozzle pitch.

  However, if the distance between the drive elements is narrowed, when connecting each of the plurality of drive elements and the driver IC by wire bonding, the number of wires is large, so that a short circuit occurs between adjacent wires (wirings). Since it tends to occur, wiring (mounting) becomes very difficult to perform wire bonding, and workability is significantly reduced. Further, in such wire bonding mounting, there is a problem that the strength of the connecting portion is weak and the yield is not improved. In addition, since the number of wires is large, wire bonding mounting takes a long time.

  Therefore, in order to solve the problem caused by the connection by such wire bonding, an outer lead bonding (OLB) is used by using a flexible substrate (flexible substrate) in which a wiring pattern functioning as an outer lead is formed in advance. ) It is considered that electrical connection is made between the drive element (piezoelectric element) and the drive device (drive circuit unit) without causing inconvenience such as short-circuiting of the wires by the connection (for example, Patent Document 2).

JP 2000-296616 A JP 2000-68989 A

  By the way, in such an OLB connection, for example, when bending force or tensile force is applied to the flexible substrate, stress is applied to the OLB connection part, and the OLB connection part is peeled off, thereby causing a conduction failure and a malfunction. There is.

  The present invention has been made in view of such circumstances, and provides a droplet discharge head, a method of manufacturing a droplet discharge head, and a droplet discharge apparatus capable of improving connection reliability in an OLB connection portion. It is intended to provide.

  In order to solve the above problems, a droplet discharge head of the present invention includes a first substrate, a drive element provided on the first substrate, and a second element provided on the drive element side of the first substrate. The board and the connection part provided at one end are joined to the terminal part of the driving element exposed to the bottom surface of the through hole by being inserted into the through hole of the second board through the conductive adhesive. A flexible substrate, wherein the flexible substrate has an opening formed at at least one end in the width direction of the connection portion, and the conductive adhesive is disposed on both surfaces of the connection portion through the opening. It is characterized by being.

  According to the droplet discharge head of the present invention, the surplus conductive adhesive discharged from between the connection portion and the terminal portion at the time of joining with the conductive adhesive is pushed out from the opening, so that the conductive adhesive is It is the state arrange | positioned on both surfaces of a flexible substrate. Therefore, the conductive adhesive provided on both sides of the flexible board through the opening functions in the same way as a rivet.For example, even when external force such as bending force is applied and stress is concentrated on the end of the connection part, it can be connected. It is possible to mitigate the progress of peeling of the part. Therefore, the droplet discharge head has high connection reliability at the joint portion between the connection portion of the flexible substrate and the terminal portion of the drive element.

Moreover, it is preferable that the connection portion is configured by bending one end of the flexible substrate. Furthermore, it is preferable that the opening is provided in the vicinity of the bent portion of the flexible substrate.
According to this configuration, since the opening is disposed in the vicinity of the bent portion where the stress is most concentrated when an external force is applied to the flexible substrate, the bonding reliability at the bonding portion between the connection portion and the terminal portion of the drive element. Can be improved.

In the droplet discharge head, the opening is preferably a notch.
According to this configuration, since the conductive adhesive is disposed in a state of covering the end of the connection portion, the separation of the connection portion can be made less likely to occur, and the connection portion and the terminal portion of the drive element can be joined. The joint reliability at the part can be improved.

In the droplet discharge head, it is preferable that the opening has a curved shape in a plan view.
According to this configuration, stress concentration on the opening formed in the connection portion can be reduced.

In the droplet discharge head, the opening is preferably formed at both ends in the width direction of the connection portion.
According to this configuration, since the opening portions are provided at both ends of the connection portion, it is possible to further improve the joint reliability at the joint portion between the connection portion and the terminal portion of the drive element.

In the droplet discharge head, it is preferable that a conductive pattern connected to a terminal portion of the driving element is routed around the opening so as to bypass the opening.
According to this configuration, since the conductive pattern is efficiently routed so as to bypass the opening, the flexible substrate can be reduced in size when the opening is formed.

  The method for manufacturing a droplet discharge head according to the present invention includes a laminating step of sequentially laminating a second substrate and a case member each having a through hole for exposing a terminal portion of the driving element on a first substrate provided with the driving element. A connecting step of inserting a connection portion formed by bending one end of the flexible substrate into the opening, and bonding the connection portion of the flexible substrate and the terminal portion of the driving element via a conductive adhesive. In the joining step, by pressing the conductive adhesive disposed between the connection portion and the terminal portion, the opening portion is formed from at least one end portion in the width direction of the connection portion. A conductive adhesive is extruded.

  According to the method for manufacturing a droplet discharge head of the present invention, surplus conductive adhesive discharged from between the connection portion and the terminal portion when the flexible substrate is joined is pushed out from the opening, and the conductive adhesive is flexible. It will be in the state arrange | positioned on both surfaces of a board | substrate. Therefore, the conductive adhesive provided on both sides of the flexible board through the opening functions in the same way as a rivet.For example, even when external force such as bending force is applied and stress is concentrated on the end of the connection part, it can be connected. The progress of peeling of the part is alleviated. Therefore, it is possible to provide a liquid droplet ejection head having high connection reliability at the joint portion between the connection portion of the flexible substrate and the terminal portion of the drive element.

In the method for manufacturing a droplet discharge head, it is preferable to use a flexible substrate in which the opening is provided in the vicinity of a bent portion of the flexible substrate.
According to this configuration, since the opening is disposed in the vicinity of the bent portion where the stress is most concentrated when an external force is applied to the flexible substrate, the bonding reliability at the bonding portion between the connection portion and the terminal portion of the drive element. Can be improved.

  A droplet discharge apparatus according to the present invention includes the droplet discharge head or the droplet discharge head manufactured by the manufacturing method.

  According to the droplet discharge device of the present invention, since the droplet discharge head having the high connection reliability at the connection portion is provided as described above, the droplet discharge device itself also prevents the occurrence of a connection failure of the flexible substrate. Will be reliable.

It is an external perspective view of a droplet discharge head. It is a disassembled perspective view of a droplet discharge head. It is a partially broken view of the perspective view of the droplet discharge head as seen from the nozzle opening side. It is AA arrow sectional drawing of FIG. It is sectional drawing which expands and shows the connection part of a flexible substrate. It is a top view of a flexible substrate. It is a principal part perspective view for demonstrating the process of mounting a flexible substrate. It is a principal part top view for demonstrating the process of mounting a flexible substrate. It is a perspective view which shows schematic structure of a droplet discharge apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, an XYZ orthogonal coordinate system is set, and the positional relationship of each member will be described with reference to this XYZ orthogonal coordinate system. Then, the short side direction (nozzle arrangement direction) of the droplet discharge head is the X axis direction, the long direction (direction perpendicular to the X axis direction) of the droplet discharge head is the Y axis direction, and the thickness direction of the droplet discharge head. A direction (that is, a direction orthogonal to the X-axis direction and the Y-axis direction) is defined as a Z-axis direction.

<Droplet ejection head>
An embodiment of a droplet discharge head of the present invention will be described with reference to FIGS. 1 is an external perspective view showing a configuration according to an embodiment of a droplet discharge head, FIG. 2 is an exploded perspective view of the droplet discharge head, and FIG. 3 is a perspective view of the droplet discharge head viewed from the nozzle opening side. FIG. 4 is a sectional view taken along line AA of FIG. 1, FIG. 5 is an enlarged sectional view showing a connecting portion of the flexible substrate, and FIG. 6 is a plan view of the flexible substrate.

  As shown in FIG. 1, the droplet discharge head 1 is provided on a nozzle substrate 21, a flow path forming substrate 22 (first substrate) provided on the upper surface of the nozzle substrate 21, and an upper surface of the flow path forming substrate 22. A vibration plate 24 that is displaced by driving the piezoelectric element 23, a reservoir forming substrate 25 (second substrate) provided on the upper surface of the vibration plate 24, a case member 101 provided on the upper surface side of the reservoir forming substrate 25, and a piezoelectric member. The substrate 1 </ b> A mainly includes a flexible substrate 27 that electrically connects an element (driving element) 23 and a driver IC (driving circuit unit) 26. In the present embodiment, the droplet discharge head is configured by one substrate 1A. However, the droplet discharge head may be configured by unitizing a plurality of substrates 1A.

  The case member 101 is made of plastic, for example. This case member is used as an attachment member when the droplet discharge head 1 is mounted on a droplet discharge device as will be described later.

  As shown in FIG. 3, the nozzle substrate 21 is made of, for example, stainless steel, glass ceramics, plastic, or silicon, and is a through-hole that penetrates the nozzle substrate 21 and discharges a functional liquid droplet. A plurality of are formed. A plurality of nozzle openings 31 formed side by side in the Y-axis direction constitute first to fourth nozzle opening groups 31A to 31D. Here, the first nozzle opening group 31A and the second nozzle opening group 31B are arranged to face each other in the X-axis direction, and the third nozzle opening group 31C and the fourth nozzle opening group 31D are arranged to face each other in the X-axis direction. . The third nozzle opening group 31C is formed adjacent to the first nozzle opening group 31A in the Y-axis direction, and the fourth nozzle opening group 31D is adjacent to the second nozzle opening group 31B in the Y-axis direction. It is formed to fit.

  In FIG. 3, the first to fourth nozzle opening groups 31 </ b> A to 31 </ b> D are shown to be configured by six nozzle openings 31, but actually, for example, about 720 nozzle openings. 31 is formed.

The flow path forming substrate 22 is formed of, for example, a rigid silicon single crystal, and the plurality of partition walls 35 are formed by anisotropically etching the silicon single crystal substrate that is the base material of the flow path forming substrate 22. ing.
In addition, a nozzle substrate 21 is fixed to the lower surface of the flow path forming substrate 22 via, for example, an adhesive or a heat welding film, and a vibration plate 24 is provided on the upper surface of the flow path forming substrate 22.

  A pressure generating chamber 36 in which the functional liquid discharged from the nozzle opening 31 is disposed is formed by a space surrounded by the flow path forming substrate 22 having the plurality of partition walls 35, the nozzle substrate 21, and the vibration plate 24. Has been. A plurality of the pressure generating chambers 36 are formed side by side in the Y-axis direction so as to correspond to the plurality of nozzle openings 31 constituting each of the first to fourth nozzle opening groups 31A to 31D.

  A first pressure generation chamber group 36A is constituted by a plurality of pressure generation chambers 36 formed corresponding to the first nozzle opening group 31A. Similarly, the second pressure generation chamber group 36B is configured by the plurality of pressure generation chambers 36 corresponding to the second nozzle opening group 31B, and the third pressure generation chamber 36B is configured by the plurality of pressure generation chambers 36 corresponding to the third nozzle opening group 31C. The chamber group 36C is configured, and the fourth pressure generating chamber group 36D is configured by the plurality of pressure generating chambers 36 corresponding to the fourth nozzle opening group 31D. The first pressure generation chamber group 36A and the second pressure generation chamber group 36B are arranged to face each other in the X-axis direction, and the third pressure generation chamber group 36C and the fourth pressure generation chamber group 36D are related to the X-axis direction. It arrange | positions so that it may mutually oppose.

One end portions of the plurality of pressure generation chambers 36 constituting the first pressure generation chamber group 36 </ b> A are communicated with each other by a communication portion 39 via a supply path 38 constituting a part of the reservoir 37. The communication portion 39 is a through hole formed in the flow path forming substrate 22 and is connected to a reservoir portion 51 described later.
Similarly, the end portions of the pressure generation chambers 36 constituting the second to fourth pressure generation chamber groups 36 </ b> B to 36 </ b> D are also communicated with each other by the communication portion 39 via the supply path 38.

  The vibration plate 24 disposed between the flow path forming substrate 22 and the reservoir forming substrate 25 is provided on the elastic film 41 so as to cover the upper surface of the flow path forming substrate 22 and on the upper surface of the elastic film 41. And a lower electrode film 42. The elastic film 41 is made of, for example, silicon dioxide having a thickness of about 1 to 2 μm, and the lower electrode film 42 is made of, for example, platinum having a thickness of about 0.2 μm. In the present embodiment, the lower electrode film 42 is an electrode common to the plurality of piezoelectric elements 23.

  The piezoelectric element 23 for displacing the diaphragm 24, that is, the driving element includes a piezoelectric film 45 provided on the upper surface of the lower electrode film 42, an upper electrode film 46 provided on the upper surface of the piezoelectric film 45, and an upper A lead electrode 47 (terminal portion) that is a lead-out wiring of the electrode film 46 is provided.

  The piezoelectric film 45 is made of, for example, a metal oxide having a thickness of about 1 μm. The upper electrode film 46 is made of, for example, platinum having a thickness of about 0.1 μm, and the lead electrode 47 is made of, for example, gold having a thickness of about 0.1 μm. An insulating film (not shown) is provided between the lead electrode 47 and the lower electrode film 42.

  A plurality of piezoelectric elements 23 are provided so as to correspond to each of the plurality of nozzle openings 31 and the pressure generation chamber 36. That is, the piezoelectric element 23 is provided for each nozzle opening 31 (for each pressure generation chamber 36). As described above, the lower electrode film 42 functions as a common electrode for the plurality of piezoelectric elements 23, and the upper electrode film 46 and the lead electrode 47 function as individual electrodes for the plurality of piezoelectric elements 23.

  Further, a first piezoelectric element group 23A is formed by a plurality of piezoelectric elements 23 provided side by side in the Y-axis direction so as to correspond to the respective nozzle openings 31 constituting the first nozzle opening group 31A. Similarly, a second piezoelectric element group 23B corresponding to the second nozzle opening group 31B is formed, a third piezoelectric element group (not shown) corresponding to the third nozzle opening group 31C is formed, and a fourth nozzle opening group 31D. Corresponding to the fourth piezoelectric element group (not shown). The first piezoelectric element group 23A and the second piezoelectric element group 23B are arranged to face each other in the X-axis direction. Further, the third piezoelectric element group and the fourth piezoelectric element group are arranged so as to face each other in the X-axis direction.

  The piezoelectric element 23 may include a lower electrode film 42 in addition to the piezoelectric film 45, the upper electrode film 46, and the lead electrode 47. That is, the lower electrode film 42 in the present embodiment may be configured to have both the function as the piezoelectric element 23 and the function as the diaphragm 24. In the present embodiment, the diaphragm 24 is constituted by the elastic film 41 and the lower electrode film 42, but the elastic film 41 may be omitted and the lower electrode film 42 may have the function of the elastic film 41.

  The reservoir forming substrate 25 is formed, for example, by etching a silicon single crystal that is the same material as the flow path forming substrate 22. Further, the reservoir forming substrate 25 is in a state where an insulating film is formed on the surface by, for example, thermal oxidation. The reservoir forming substrate 25 is preferably formed of a material having a thermal expansion coefficient substantially the same as the thermal expansion coefficient of the flow path forming substrate 22. For example, glass or a ceramic material may be used.

As shown in FIG. 4, reservoir portions 51 corresponding to the respective communication portions 39 are formed on the reservoir forming substrate 25 so as to extend in the Y-axis direction. The reservoir 37 is configured by the reservoir portion 51 and the communication portion 39 described above.
In addition, the reservoir forming substrate 25 is formed with an introduction path 52 that is connected to the side wall of each communication portion 39 and introduces the functional liquid into each communication portion 39.

A compliance substrate 53 is bonded to the upper surface of the reservoir forming substrate 25. The compliance substrate 53 includes a sealing film 54 and a fixing plate 55.
The sealing film 54 is formed of a material having low rigidity and flexibility such as a polyphenylene sulfide film having a thickness of about 6 μm. The upper part of the reservoir 51 is sealed with the sealing film 54.

  The fixing plate 55 is made of a hard material such as a metal such as stainless steel having a thickness of about 30 μm. A region of the fixing plate 55 corresponding to the reservoir 51 is an opening 56 that is completely removed in the thickness direction. Therefore, the upper portion of the reservoir 51 is sealed only by the flexible sealing film 54, and thus is a flexible portion 57 that can be deformed by a change in internal pressure. Further, the case member 101 is provided on the compliance substrate 53.

  In addition, the compliance substrate 53 and the case member 101 outside the reservoir unit 51 are formed with a functional liquid introduction port 58 that communicates with the introduction path 52 and supplies the functional liquid to the reservoir unit 51. Normally, when the functional liquid is supplied from the functional liquid introduction port 58 to the reservoir section 51, a pressure change occurs in the reservoir section 51 due to, for example, the flow of the functional liquid at the time of driving the piezoelectric element 23 or ambient heat. However, as described above, since the upper portion of the reservoir portion 51 is the flexible portion 57 sealed only by the sealing film 54, the flexible portion 57 is bent and deformed to absorb the pressure change. Therefore, the inside of the reservoir 51 is maintained at a constant pressure. The other portions are held at a sufficient strength by the fixing plate 55. The case member 101 is provided in a non-contact state with the flexible portion 57 so as not to impair the deformation of the flexible portion 57.

  A groove-like opening (through hole) 60 extending in the Y-axis direction is formed in the central portion of the reservoir forming substrate 25 in the X-axis direction. Each of the openings 60 is partitioned by two wall portions 25A extending in the Y-axis direction, each of the two openings 60 aligned in the X-axis direction. First and second sealing portions 61A and 61B for sealing the first to fourth piezoelectric element groups 23A to 23D with the diaphragm 24, and third and fourth sealing portions are formed. More specifically, the first sealing portion 61A seals the first piezoelectric element group 23A corresponding to the first pressure generating chamber group 36A between the diaphragm 24 and the second sealing portion 61B. The element group 23B is sealed. Although the third sealing portion and the fourth sealing portion are not shown in FIG. 4, they seal the third and fourth piezoelectric element groups.

  In the reservoir forming substrate 25, a space that does not hinder the movement of the piezoelectric element 23 is secured in a region facing the piezoelectric element 23, and a piezoelectric element holding portion 62 that can seal the space is formed. . The piezoelectric element holding part 62 is formed in each of the first and second sealing parts 61A and 61B and the third and fourth sealing parts, and covers the first to fourth piezoelectric element groups 23A to 23D. It is formed in size. Of the piezoelectric elements 23, at least the piezoelectric film 45 is sealed in the piezoelectric element holding portion 62.

  As described above, the reservoir forming substrate 25 functions as a sealing member for blocking the piezoelectric element 23 from the external environment and sealing the piezoelectric element 23. By sealing the piezoelectric element 23 with the reservoir forming substrate 25, it is possible to prevent the piezoelectric element 23 from being damaged by an external environment such as moisture. In the present embodiment, the inside of the piezoelectric element holding part 62 is simply sealed. However, for example, the space inside the piezoelectric element holding part 62 is maintained in a vacuum, nitrogen or argon atmosphere, etc. The inside of the part 62 can be kept at low humidity, and the destruction of the piezoelectric element 23 can be prevented more reliably.

In addition, among the piezoelectric elements 23 sealed by the piezoelectric element holding portion 62 of the first sealing portion 61A, one end portion of the lead electrode 47 extends to the outside of the first sealing portion 61A and has an opening. The portion 60 is disposed on the flow path forming substrate 22 exposed.
Similarly, among the piezoelectric elements 23 sealed by the piezoelectric element holding portion 62 of the second sealing portion 61B, the other end portion of the lead electrode 47 extends to the outside of the second sealing portion 61B, and is opened. The portion 60 is disposed on the flow path forming substrate 22 exposed. In addition, among the piezoelectric elements 23 sealed by the piezoelectric element holding portions 62 of the third and fourth sealing portions, a part of the lead electrode 47 extends to the outside of the third and fourth sealing portions, It arrange | positions on the flow-path formation board | substrate 22 exposed in the opening part 60 provided between 3rd and 4th sealing part.

  In addition, an opening 102 formed along the Y-axis direction is formed at the center of the case member 101 in the X-axis direction. The opening 102 has a size including at least the opening area of the opening 60 formed in the reservoir forming substrate 25. As shown in FIGS. 1 and 2, the holding area (inner wall surface) 103 of the flexible substrate 27 is formed. Is formed in a notch shape. Hereinafter, the opening constituted by the opening 60 of the reservoir forming substrate 25 and the opening of the flexible substrate 27 is collectively referred to as a through opening (opening) 150.

  The driver IC 26 is a driver IC having, for example, a semiconductor integrated circuit (IC) including a circuit board and a driving circuit, and four driver ICs 26 are provided according to the first to fourth nozzle opening groups 31A to 31D. Each driver IC 26 is flip-chip mounted on a predetermined area (mounting portion) 27 </ b> A on one surface of the flexible substrate 27.

  The flexible substrate 24 on which such a driver IC 26 is mounted is in a state where one end side is inserted into the through opening 150 of the case member 101 and the reservoir forming substrate 25 as shown in FIG. The flexible substrate 24 electrically connects the lead electrode 47 of the piezoelectric element 23 exposed on the bottom surface of the through opening 150 and the driver IC 26.

  Specifically, the flexible substrate 27 bends between the mounting area of the driver IC 26 and the terminal portion 73 so that the end portion on the terminal portion 73 side, that is, the connection portion 27b is placed in the through opening 150 (FIGS. 4 and 5). By inserting, the lead electrode 47 disposed in the through opening 150 and the terminal portion 73 are connected. The terminal portion 73 and the lead electrode 47 are connected to each other by a conductive adhesive 79 such as an anisotropic conductive paste (ACP: Anisotropic Conductive Paste). Hereinafter, the connection structure between the terminal portion 73 and the lead electrode 47 is referred to as an OLB connection portion 100.

  The flexible substrate 27 is in contact with the film base 71 and the first wiring pattern 72, the second wiring pattern 74, the ground wiring 76, and the piezoelectric element 23 formed on one surface of the film base 71 as shown in FIG. A terminal portion 73 to be connected is provided. The terminal portion 73 side of the flexible substrate is bent by a bent portion 91 indicated by an O line in the drawing, and one end portion generated by the bent portion 91 constitutes a connecting portion 27b connected to the lead electrode 47 of the piezoelectric element 23. is doing.

  The film base 71 is an insulating film made of polyimide having a thickness of about 25 μm, for example, and the first wiring pattern 72, the second wiring pattern 74, and the like made of a conductive material such as copper are formed on the lower surface 27a thereof. The ground wiring 76 is formed by a technique such as electrolytic plating or etching by a printing method. Further, a terminal portion 73 is formed in a predetermined region of the lower surface 27 a and is connected to one end of the first wiring pattern 72.

  In the flexible substrate 27 of the present embodiment, the notches 90 are formed at both ends in the width direction of the connecting portion 27b. The notch 90 is provided in the vicinity of the bent portion 91 of the connecting portion 27b, and has a curved shape having a substantially semicircular shape in plan view. Thus, the curved notch 90 can alleviate stress concentration at the opening end, and the flexible substrate 27 can be prevented from being damaged at the notch 90. Further, the terminal portion 73 is routed around the connection portion 27b so as to bypass the notch 90. Thereby, the terminal portion 73 is efficiently routed, and the flexible substrate 27 in which the notch 90 is formed can be reduced in size.

  A driver IC 26 for driving the piezoelectric element 23 is disposed in a predetermined region (mounting portion) 27A of the lower surface 27a of the flexible substrate 27, and is flip-chip mounted on each lower surface 27a of the flexible substrate 27. The corresponding first wiring pattern 72, second wiring pattern 74, and ground wiring 76 are connected. Further, a resin (adhesive) 78 for increasing the connection strength is provided between the driver IC 26 and the flexible substrate 27 (see FIG. 5). The center of the driver IC 26 coincides with the center (specifically, the center of the opening 60) of the drive element array composed of the plurality of drive elements 23 in a state where the flexible substrate 27 is connected to the piezoelectric element 23.

  Further, the flexible substrate 27 is formed with an external signal input portion 77 that is electrically connected to the external controller CT, and includes a second wiring pattern 74 and a ground wiring 76 that are connected to the driver IC 26. An external signal input from the external signal input unit 77 is input to the driver IC 26 via the second wiring pattern 74.

  Incidentally, the flexible substrate 27 is connected to the external controller CT in a state where the external signal input unit 77 side is bent as shown in FIG. Therefore, a load is applied to the OLB connection portion 100 due to bending stress or tensile force acting on the flexible substrate 27.

  When bending force or tensile force is applied to the flexible substrate 27, stress concentrates on the end portion in the width direction of the flexible substrate 27. And in the connection part 27b which comprises the OLB connection part 100, since stress concentrates on the edge part in the width direction similarly, there exists a possibility that joining strength may fall.

  On the other hand, in this embodiment, the conductive adhesive 79 used for connection between the flexible substrate 27 and the lead electrode 47 is formed on both surfaces of the flexible substrate 27 (connection portion 27b) through the notches 90 formed in the connection portion 27b. Has been placed.

  Specifically, as shown in FIGS. 4 and 5, the conductive adhesive 79 protrudes from the notch 90. That is, it is cured while being pushed out from the notch 90. Thereby, the conductive adhesive 79 is in a state of covering a part of both end portions of the connection portion 27b in a plan view (see FIG. 8). Thereby, the conductive adhesive 79 has the same function as a rivet. Therefore, both end portions of the connecting portion 27 b are fixed by a rivet structure made of the conductive adhesive 79.

  Therefore, when bending force or tensile force is applied to the flexible substrate 27, the end portion of the flexible substrate 27 where the stress is concentrated, that is, the end portion of the connection portion 27b is fixed by the conductive adhesive 79. It is possible to mitigate the progress of peeling. Therefore, the connection reliability in the OLB connection unit 100 is greatly improved.

(Method for manufacturing droplet discharge head)
Next, a method for manufacturing the droplet discharge head 1 having the above-described configuration will be described. FIG. 7 is a cross-sectional view showing a part of the manufacturing process of the droplet discharge head (OLB mounting process). In the following description, the procedure for connecting the driver IC 26 and the piezoelectric element 23 will be mainly described. Among the droplet discharge heads 1, the nozzle substrate 21, the flow path forming substrate 22, the reservoir forming substrate 25, and the piezoelectric element 23 are described. It is assumed that the manufacturing, connection, and arrangement of the flexible substrate 27 and the like have been completed.

  The nozzle substrate 21, the flow path forming substrate 22 on which the piezoelectric element 23 is formed, and the reservoir forming substrate 25 are sequentially bonded (bonding step). Next, the flexible substrate 27 is mounted in the corresponding through opening 150 (opening 60) of the reservoir forming substrate 25 and the case member 101. As shown in FIG. 7, each terminal provided on the connection portion 27 b of the flexible substrate 27 with the connection portion 27 b inserted into the through opening 150 and the driver IC 27 mounted on the mounting portion 27 </ b> A protruding. The part 73 and each lead electrode 47 of the piezoelectric element 23 are brought into contact with each other in an aligned state and temporarily joined. A conductive adhesive 79 is provided in advance on the lower surface of the terminal portion 73 or the upper surface of the lead electrode 47.

  For mounting, the flexible substrate 27 is sucked using a bonding tool T as shown in FIG. 7, and the terminal portion 73 is lead by pressing the connecting portion 27b while aligning the terminal portion 73 with the lead electrode 47. It is brought into contact with the electrode 47. The bonding tool T may be aligned with the flexible substrate 27 by providing an alignment mark (not shown) on the connection portion 27 b of the flexible substrate 27, or the position of the terminal portion 73 and the lead electrode 47. It can also be used together.

  Then, the connecting portion 27b is pressed and heated by the bonding tool T in a state where the connecting portion 27b of the flexible substrate 27 and the lead electrode 47 of the piezoelectric element 23 are opposed to each other. Since at least one of the terminal portion 73 and the lead electrode 47 is provided with the anisotropic conductive material 79 in advance, the bonding tool T is pressed and heated while the anisotropic conductive material 79 is interposed. The terminal portion 73 and the lead electrode 47 are easily electrically connected (connection process).

  At this time, the softened conductive adhesive 79 expands so as to fill the gap between the terminal portion 73 and the lead electrode 47 as shown in FIGS. 7 and 8 and is pushed out from between the connection portion 27 b and the lead electrode 47. The surplus conductive adhesive 79 that has been pushed out is pushed out from the inside of the notch 90, and is in a state of wrapping around the upper surface side of the connection portion 27 b. Thus, the conductive adhesive 79 is disposed on both sides of the connection portion 27b through the notch 90. Similarly, all the flexible substrates 27 are mounted in the through opening 150 (opening 60). The droplet discharge head 1 is manufactured as described above.

  According to this embodiment, when the flexible substrate 27 is mounted, the surplus conductive adhesive 79 discharged from between the connection portion 27 b and the lead electrode 47 is pushed out from the notch 90, and the conductive adhesive 79 becomes flexible substrate 27. It will be in the state arranged on both sides. Therefore, when the conductive adhesive 79 provided on both surfaces of the flexible substrate 27 via the notch 90 functions in the same manner as the rivet, for example, when an external force such as a bending force is applied and stress is concentrated on the end of the connection portion 27b. However, the progress of peeling of the connecting portion 27b is alleviated. Therefore, the droplet discharge head 1 having high connection reliability in the OLB connection unit 100 can be provided.

<Droplet ejection device>
Next, an example of the droplet discharge apparatus IJ of the present invention provided with the above-described droplet discharge head 1 will be described with reference to FIG. FIG. 9 is a perspective view showing a schematic configuration of the droplet discharge device IJ.

  In FIG. 9, the droplet discharge device IJ includes a droplet discharge head 1, a drive shaft 4, a guide shaft 5, an external controller CT, a stage 7, a cleaning mechanism 8, a base 9, and a heater 6. I have. The droplet discharge head 1 is attached to a droplet discharge device IJ via a case member 101 in a carriage (not shown). The stage 7 supports the substrate P from which the functional liquid is discharged by the droplet discharge head 1, and includes a fixing mechanism (not shown) that fixes the substrate P at a reference position. The functional liquid is discharged from the nozzle opening of the droplet discharge head 1 onto the substrate P supported by the stage 7.

  A drive motor 2 is connected to the drive shaft 4. The drive motor 2 is composed of a stepping motor or the like. When a drive signal in the Y-axis direction is supplied from the external controller CT, the drive shaft 4 is rotated. When the drive shaft 4 rotates, the droplet discharge head 1 moves in the Y-axis direction. The guide shaft 5 is fixed so as not to move with respect to the base 9. The stage 7 includes a drive motor 3. The drive motor 3 is composed of a stepping motor or the like. When a drive signal in the X-axis direction is supplied from the external controller CT, the stage 7 is moved in the X-axis direction.

  The external controller CT supplies a voltage for controlling droplet ejection to the droplet ejection head 1. Further, the external controller CT supplies a drive pulse signal for controlling the movement of the droplet discharge head 1 in the Y-axis direction to the drive motor 2 and also supplies the drive motor 3 to the X-axis direction of the stage 7. A drive pulse signal for controlling movement is supplied.

The cleaning mechanism 8 cleans the droplet discharge head 1 and includes a drive motor (not shown). By driving the drive motor, the cleaning mechanism 8 moves in the X-axis direction along the guide shaft 5. The movement of the cleaning mechanism 8 is also controlled by the external controller CT. Here, the heater 6 is means for heat-treating the substrate P by lamp annealing, and evaporates and dries the solvent contained in the functional liquid applied on the substrate P. The power on and off of the heater 6 is also controlled by the external controller CT.
The droplet discharge device IJ discharges droplets onto the substrate P while relatively scanning the droplet discharge head 1 and the stage 7 supporting the substrate P.

  Since such a droplet discharge device IJ includes the droplet discharge head 1 having high connection reliability in the OLB connection portion 100 of the flexible substrate 27 as described above, the droplet discharge device IJ itself is also included. In addition, the conduction failure in the OLB connection unit 100 is prevented and the reliability is high.

  In the above-described embodiment, the functional liquid discharged from the droplet discharge head 1 includes a liquid crystal display device forming material for forming a liquid crystal display device, and an organic EL forming device for forming an organic EL display device. It includes materials, wiring pattern forming materials for forming wiring patterns of electronic circuits, and the like. Thereby, the droplet discharge apparatus IJ can manufacture each of the devices with the functional liquid discharged based on the droplet discharge method.

  The preferred embodiments according to the present invention have been described above with reference to the accompanying drawings. However, it goes without saying that the present invention is not limited to such examples, and the above embodiments may be combined. It is obvious for those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs to.

  For example, in the above embodiment, the case where the flexible substrate 27 on which the driver IC 26 is mounted is bonded to the lead electrode 47 of the piezoelectric element 23 has been described. However, the flexible substrate 27 is connected to the lead electrode 47 with the mounting portion 27A protruding from the opening. After bonding to 47, the driver IC 26 may be mounted on the mounting portion 27A.

  Moreover, although the case where the notch 90 was formed in both the ends in the width direction of the connection part 27b was demonstrated in the said embodiment, you may make it provide the notch 90 only in at least one edge part in the connection part 27b. . Further, an opening may be formed instead of the notch 90 at at least one end in the width direction of the connecting portion 27b. Further, the shape of the notch is not limited to the above-described substantially semicircular shape in plan view, and may be an elliptical shape, a rectangular shape, or the like.

DESCRIPTION OF SYMBOLS 1 ... Droplet discharge head, 22 ... Channel formation board | substrate (1st board | substrate), 23 ... Piezoelectric element (drive element), 25 ... Reservoir formation board | substrate (2nd board | substrate), 26 ... Driver IC (drive circuit part), 27 ... flexible substrate, 27b ... connection part, 28a ... inner wall surface, 47 ... lead electrode (terminal part), 60 ... opening (through hole), 79 ... conductive adhesive, 90 ... notch, 101 ... case member, 102 ... Opening (through hole), 150 ... through opening (through hole), IJ ... droplet discharge device

Claims (10)

A first substrate;
A driving element provided on the first substrate;
A second substrate provided on the drive element side of the first substrate;
A flexible substrate joined via a conductive adhesive to a terminal portion of the drive element exposed at the bottom surface of the through hole by inserting a connection portion provided at one end into the through hole of the second substrate; With
The flexible substrate is characterized in that an opening is formed at at least one end in the width direction of the connection portion, and the conductive adhesive is disposed on both surfaces of the connection portion through the opening. Droplet discharge head.   The droplet discharge head according to claim 1, wherein the connection portion is configured by bending one end of the flexible substrate.   The droplet discharge head according to claim 2, wherein the opening is provided in the vicinity of a bent portion of the flexible substrate.   The droplet discharge head according to claim 1, wherein the opening is a notch.   The droplet discharge head according to claim 1, wherein the opening has a curved shape in a plan view.   The liquid droplet ejection head according to claim 1, wherein the opening is formed at both ends in the width direction of the connection portion.   The conductive pattern connected to the terminal portion of the drive element is routed around the connection portion so as to bypass the opening portion. Droplet discharge head. A laminating step of sequentially laminating a second substrate and a case member each having a through hole for exposing a terminal portion of the driving element on the first substrate provided with the driving element;
A joining step of inserting a connection portion formed by bending one end of a flexible substrate into the opening, and joining the connection portion of the flexible substrate and the terminal portion of the driving element via a conductive adhesive, and
In the joining step, the conductive conductive material is pressed from the opening formed in at least one end in the width direction of the connection portion by pressing the conductive adhesive disposed between the connection portion and the terminal portion. A method for manufacturing a droplet discharge head, characterized by extruding an adhesive material.   9. The method of manufacturing a droplet discharge head according to claim 8, wherein the flexible substrate is one in which the opening is provided in the vicinity of a bent portion of the flexible substrate.   A droplet discharge apparatus comprising the droplet discharge head according to claim 1 or the droplet discharge head manufactured by the manufacturing method according to claim 8 or 9.

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