JP2010240850A - Liquid droplet ejection head, method for manufacturing the liquid droplet ejection head, and liquid droplet ejection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid droplet ejection head which achieves improvement in connection reliability at an OLB (Outer Lead Bonding) connection part by preventing elongation of a wiring due to bending process of a flexible board, and to provide a method for manufacturing the liquid droplet ejection head and a liquid droplet ejection device. <P>SOLUTION: The liquid droplet ejection head includes a first substrate 22, a driving element 23 provided on the first substrate 22, a second substrate 25 provided on the driving element 23 side on the first substrate 22, and the flexible board 27 connected to a terminal part 47 of the driving element 23 exposed to a base of a through-hole 150 of the second substrate 25 by inserting a connection part 27b made by bending one end into the through-hole 150. The flexible board 27 has base material 71 and the wiring 72 provided on the base material 71 and electrically connected to the terminal part 47 of the driving element 23, and the base material 71 provided inside at a bent part 91 forming the connection part 27b is separated from the wiring 72. <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 2002-368348 A JP 2005-247453 A

  By the way, the flexible substrate used for such OLB connection is formed by bending. For this reason, for example, when processing with a small bending radius is performed, the wiring formed on the base material may be extended, and the cross-sectional area of the wiring may be reduced and the wiring resistance may be increased. The wiring extended in this way is easy to break, which has been a factor of reducing the conduction reliability in the OLB connection portion.

  The present invention has been made in view of such circumstances, and a droplet discharge head, a droplet, and the like, which have improved connection reliability in an OLB connection portion by preventing the wiring from being stretched by bending a flexible substrate. It is an object of the present invention to provide a method for manufacturing a discharge head and a droplet discharge device.

  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. A board and a flexible board connected to the terminal part of the drive element exposed at the bottom of the through hole by inserting a connection part formed by bending one end into the through hole of the second board; The flexible substrate has a base material and a wiring provided on the base material and electrically connected to the terminal portion of the drive element, and the base material inside the bent portion forming the connection portion Is separated from the wiring.

  According to the droplet discharge head of the present invention, since the base material and the wiring are separated from each other in the bent portion, the wiring is prevented from extending when the flexible substrate is bent. Therefore, even when the flexible substrate is bent, a reduction in the cross-sectional area of the wiring or an increase in the internal resistance of the wiring caused by the elongation of the wiring is prevented. Therefore, a droplet discharge head is obtained in which a flexible substrate with high reliability in which problems due to bending are prevented is connected to the drive element.

In the droplet discharge head, it is preferable that the wiring is formed by applying a gold plating to a wiring pattern made of copper.
According to this structure, the wiring which plated the wiring pattern which consists of copper on the base material is formed on the base material, and hard materials, such as nickel plating, are not contained. Therefore, it is possible to reduce the risk of disconnection of the wiring when the flexible substrate is bent.

  The manufacturing method of the droplet discharge head of the present invention uses a flexible substrate in which wiring is formed on a base material, a peeling step of peeling the wiring from the base material at a predetermined position, and after the peeling step, A bending step of bending the flexible substrate so that the base material is inside with respect to a predetermined position to provide a connection portion at one end of the flexible substrate and separating the base material from the wiring at the bending portion; and driving A laminating step of laminating a second substrate having an opening that exposes a terminal portion of the driving element on a first substrate provided with an element; and inserting the connecting portion of the flexible substrate into the opening; A bonding step of bonding the connection portion of the substrate and the terminal portion of the driving element via a conductive adhesive.

  According to the manufacturing method of the droplet discharge head of the present invention, the portion where the substrate and the wiring are separated is bent, so that the wiring is prevented from extending at the bent portion. Therefore, a reduction in the cross-sectional area of the wiring or an increase in the internal resistance of the wiring caused by the extension of the wiring is prevented. Therefore, it is possible to manufacture a droplet discharge head in which a flexible substrate with high reliability in which problems due to bending are prevented is connected to the drive element.

Further, in the method for manufacturing the droplet discharge head, in the peeling step, the flexible substrate is configured such that one surface side and the other surface side of the flexible substrate defined by a reference axis passing through the predetermined position are opposed to each other. Is preferably bent.
According to this structure, a base material and wiring can be peeled easily and reliably in a predetermined position.

In the method of manufacturing the droplet discharge head, it is preferable that the flexible substrate is bent in the peeling step in a state where the predetermined position is selectively heated.
According to this configuration, the wiring can be easily peeled off from the substrate by heating the interface between the wiring and the substrate.

  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 highly reliable flexible substrate includes the droplet discharge head connected to the driving element, the droplet discharge device itself is also highly 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 figure which shows the manufacturing process of a flexible substrate. It is a figure 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, the reservoir forming substrate 25 is formed with a reservoir portion 51 corresponding to each of the communication portions 39 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. These openings 60 are partitioned by two wall portions 25A extending in the Y-axis direction, each of the two openings 60 arranged 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, in the piezoelectric element 23 sealed by the piezoelectric element holding part 62 of the second sealing part 61B, the other end of the lead electrode 47 extends to the outside of the second sealing part 61B, and the opening 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, and the holding area 103 of the driver IC 26 is formed in a cutout shape as shown in FIGS. Has been.
Hereinafter, the openings formed by the opening 60 of the reservoir forming substrate 25 and the opening of the flexible substrate 27 are 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 region (mounting region) on one surface of the flexible substrate 27. And it molds with the heat-radiating resin 65 to the inner surface 102a of the holding | maintenance area | region 103 of the said opening part 102 formed in the case member 101 (refer FIG. 3).

  As shown in FIG. 2, the flexible substrate 24 is in a state where one end side is inserted into the through opening 150 formed in the case member 101 and the reservoir forming substrate 25. 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 is penetrated by inserting a connecting portion 27b formed by bending between a mounting region of the driver IC 26 and one end portion into the through opening 150 (FIGS. 4 and 5). The lead electrode 47 disposed in the opening 150 and the first wiring 72 are connected. The first wiring 72 and the lead electrode 47 are connected to each other by a conductive adhesive 79 such as an anisotropic conductive paste (ACP). Hereinafter, the connection structure between the first wiring 72 and the lead electrode 47 is referred to as an OLB connection unit 100.

  As shown in FIG. 6, the flexible substrate 27 includes a film base 71, a first wiring 72, a second wiring 74, and a ground wiring 76 formed on one surface of the film base 71. One end side of the flexible substrate is bent by a bent portion 91 indicated by an O line in the drawing, and a first wiring 72 arranged at one end portion generated by the bent portion 91 is connected to the lead electrode 47 of the piezoelectric element 23. The connecting portion 27b is configured.

  The film base 71 is an insulating film made of polyimide having a thickness of about 25 μm, for example, and the first wiring 72, the second wiring 74, and the ground wiring made of a conductive material such as copper are formed on the lower surface 27a thereof. 76 is formed by a technique such as electrolytic plating or etching by a printing method. Specifically, in the present embodiment, the first wiring 72, the second wiring 74, and the ground wiring 76 are configured by applying a gold plating to a wiring pattern made of copper.

  The flexible substrate 27 of the present embodiment is formed in a state in which the film base 71 is separated from the first wiring 72 in the bent portion 91. That is, the film base 71 has a convex portion 72 a that protrudes from the surface of the first wiring 72 at the bent portion 91. As described above, since the film base 71 is separated from the first wiring 72 in the bent portion 91, the first wiring 72 is prevented from being stretched during the bending process when the flexible substrate 27 described later is manufactured. Therefore, the first wiring 72 is prevented from decreasing in cross-sectional area and increasing in internal resistance due to elongation.

  A driver IC 26 for driving the piezoelectric element 23 is disposed in a predetermined area (mounting portion) on the lower surface 27a of the flexible substrate 27, and can be dealt with by flip chip mounting on each lower surface 27a of the flexible substrate 27. The first wiring 72, the second wiring 74, and the 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).

  Further, the flexible substrate 27 is formed with an external signal input unit 77 that is electrically connected to an external controller (not shown), and is configured by a second wiring pattern 74 and a ground wiring 76 that are connected to the driver IC 26. Yes. An external signal input from the external signal input unit 77 is input to the driver IC 26 via the second wiring pattern 74.

(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 diagram illustrating a manufacturing process of the flexible substrate. FIG. 8 is a cross-sectional view showing a part of the manufacturing process of the droplet discharge head (OLB connection 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 case member 101 are described. It is assumed that the manufacturing, connection, and arrangement of the piezoelectric element 23 and the like have already been completed.

First, the flexible substrate 27 is prepared.
As shown in FIG. 6, various wirings such as a first wiring 72, a second wiring 74, and a ground wiring 76 are formed on the surface of the film base 71. These are formed on the film base 71 using a technique such as electrolytic plating or etching using a printing method. Here, the 1st wiring 72 which comprises the connection part 27b is accurately formed according to the space | interval (nozzle pitch) of the nozzle openings 31, ie, the space | interval of the piezoelectric elements 23. FIG.

  Then, the driver IC 26 is mounted on the flexible substrate 27. In this case, the driver IC 26 is flip-chip mounted on a mounting region (predetermined region) on one surface of the film base 71 of the flexible substrate 27 (the lower surface 27a of the flexible substrate 27). Thereafter, the flexible substrate 27 and the driver IC 26 are fixed by the resin 78, respectively.

  Subsequently, the flexible substrate 27 on which the driver IC 26 is mounted is subjected to a bending process (for example, a press process) so that the film base 71 is located inside at a position corresponding to the one-dot chain line O shown in FIG. The connecting portion 27b is formed in

  By the way, when such a bending process is performed with a small diameter (for example, a radius of about 100 μm), there is a possibility that the wiring cross section is reduced and the wiring resistance is increased due to the extension of the first wiring 72 arranged on the outside. Moreover, there is a possibility that the risk of disconnection may increase due to the extension of the first wiring 72.

  Therefore, in the present embodiment, prior to bending the flexible substrate 27, a peeling process described later is performed. In the peeling step, the first wiring 72 is peeled from the film base 71 at a predetermined position. Here, the predetermined position is a position corresponding to the bent portion 91 (a position indicated by a one-dot chain line O in FIG. 6).

  Specifically, in this embodiment, as shown in FIG. 7A, both end portions of the flexible substrate 27 are sandwiched by clamps 90 each consisting of a pair of upper and lower sides. Then, one clamp 90 is fixed and the other clamp 90 is operated in the vertical direction. Thereby, the flexible substrate 27 is bent so that one side and the other side with respect to the reference axis C passing through a predetermined position are opposed to each other.

  In this embodiment, the flexible substrate 27 is bent in a state where the film base 71 of the reference axis C is selectively irradiated with laser light and heated using the laser light source device 92. The film base 71 partially heated in this way has low adhesion at the interface with the first wiring 72. Therefore, the film base 72 is peeled from the first wiring 72 at a predetermined position (reference axis C) as shown in FIG.

  Subsequently, the flexible substrate 27 is bent so that the film base 71 is on the inner side with reference to a predetermined position where the peeling occurs in the flexible substrate 27. At this time, as shown in FIG. 7C, the flexible substrate 27 is bent by being pressed against the molding die 93. The bending angle θ is, for example, 30 °.

  An escape portion 93 a is provided at the tip of the molding die 93 so as not to contact the peeled film base 71. Therefore, the flexible substrate 27 bends so that the film base 71 enters the escape portion 93 a when pressed against the molding die 93. Thereby, the film base 72 can be largely peeled from the surface of the first wiring 71, and the convex portion 72 a can be formed on the film base 71.

  In the present embodiment, since the first wiring 72 is bent at a position where the first wiring 72 is peeled off from the film base 71, the first wiring 72 is not pulled at the time of bending, and the wiring cross-sectional area is reduced due to elongation or the wiring resistance. Is prevented from occurring. In addition, since the load applied to the first wiring 72 is reduced, a decrease in strength due to bending can be reduced, and the risk of disconnection in the first wiring 72 can be reduced. Furthermore, since the first wiring 72 of the present embodiment does not include a hard material such as nickel plating as described above, the risk that the first wiring 72 is disconnected during bending is further reduced.

  Subsequently, the flexible substrate 27 after being bent is removed from the molding die 93. Then, the flexible substrate 27 is restored in a direction opposite to the bending direction, and finally is in a state of being bent by approximately 90 ° as shown in FIG. The bending process which comprises the connection part 27b in the flexible substrate 27 is complete | finished by the above process.

  Next, the flexible substrate 27 is mounted in the through opening 150. As shown in FIG. 8, the first wiring 72 of the connecting portion 27b is brought into contact with the lead electrode 47 of the piezoelectric element 23 and temporarily joined. An anisotropic conductive material 79 is provided in advance on the lower surface of the connection portion 27b 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. 8, and the first wiring 72 is pressed by pressing the connecting portion 27 b while aligning the first wiring 72 with the lead electrode 47. Is brought into contact with the lead 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 first wiring 72 and the lead electrode 47 may be aligned. It can also be used for alignment.

  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. At this time, since the anisotropic conductive material 79 is provided in advance on at least one of the first wiring 72 and the lead electrode 47, pressing and heating by the bonding tool T with the anisotropic conductive material 79 interposed therebetween. As a result, the first wiring 72 and the lead electrode 47 are easily electrically connected. In addition, since the softened anisotropic conductive material 79 expands so as to fill the gap between the first wiring 72 and the lead electrode 47, the connection portion 27 b of the flexible substrate 27 and the lead electrode 47 of the piezoelectric element 23 are strengthened. It becomes possible to connect to.

  In the present embodiment, the driver IC 26 provided on the flexible substrate 27 is fixed to the case member 101 at the same time as the electrical connection between the connection portion 27 b of the flexible substrate 27 and the lead electrode 47 of the piezoelectric element 23 is performed. .

  Specifically, similar to the anisotropic conductive material 79, a heat radiating resin 65 is applied in advance to the inner surface 102 a of the holding region 103 of the case member 101, and the driver IC 26 is attached to the case member 101 on the heat radiating resin 65. Fix it. The heat-dissipating resin 65 is not cured until the connecting portion 27b of the flexible substrate 27 is securely connected to the lead electrode 47 of the piezoelectric element 23. As a result, the first wiring 72 and the lead electrode 47 can be connected well.

  Thereafter, the bonding tool T is separated from the flexible substrate 27 and left for a predetermined time to perform the main bonding of the OLB connection portion 100. Similarly, all the flexible boards 27 are mounted in the through openings 150. The droplet discharge head 1 is manufactured as described above.

  According to the present embodiment, since the film base 71 and the first wiring 72 are separated from each other at a position corresponding to the bending portion 91, it is possible to prevent the first wiring 72 from extending during the bending process of the flexible substrate 27. . Therefore, even when the flexible substrate 27 is bent, a reduction in the cross-sectional area of the first wiring 72 or an increase in the internal resistance of the first wiring 72 is prevented. Therefore, the droplet discharge head 1 with high reliability is obtained in which problems such as poor conduction in the OLB connection portion 100 due to bending are prevented.

<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, a stage 7, a cleaning mechanism 8, a base 9, and a heater 6. ing. 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 an external controller, 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 an external controller, the stage 7 is moved in the X-axis direction.

  The external controller supplies a voltage for controlling droplet ejection to the droplet ejection head 1. Further, the external controller 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 moves the stage 7 in the X-axis direction to the drive motor 3. A drive pulse signal for controlling 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 an external controller. 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 an external controller.
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, after the connection portion 27b is bonded to the lead electrode 47, the driver IC 26 is connected to the flexible substrate 27. You may make it mount in.

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 DESCRIPTION OF SYMBOLS ... Flexible board, 27b ... Connection part, 47 ... Lead electrode (terminal part), 71 ... Film base material, 72 ... First wiring, 72a ... Convex part, 79 ... Conductive adhesive, 91 ... Bending part, 100 ... OLB connection part, 101 ... case member, 102 ... opening, 150 ... through opening, IJ ... droplet ejection device

Claims (6)

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 connecting portion formed by bending one end is inserted into the through hole of the second substrate, and is connected to the terminal portion of the driving element exposed at the bottom surface of the through hole; and
The flexible substrate has a base material and a wiring provided on the base material and electrically connected to the terminal portion of the drive element, and the base material inside the bent portion forming the connection portion Is a liquid droplet ejection head characterized by being spaced apart from the wiring.   The droplet discharge head according to claim 1, wherein the wiring is a wiring pattern made of copper and plated with gold. Using a flexible substrate in which wiring is formed on a base material, a peeling step of peeling the wiring from the base material at a predetermined position;
After the peeling step, the flexible substrate is bent so that the base material is inside with respect to the predetermined position, and a connection portion is provided at one end of the flexible substrate, and the base material is separated from the wiring at the bending portion. Bending process,
A laminating step of laminating a second substrate having an opening exposing the terminal portion of the driving element on the first substrate provided with the driving element;
A bonding step of inserting the connection portion 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. A method for manufacturing a droplet discharge head.   The said peeling process WHEREIN: The said flexible substrate is bent so that the one surface side and the other surface side of the said flexible substrate prescribed | regulated by the reference axis which passes through the said predetermined position may be made to oppose. Manufacturing method of a liquid droplet discharge head.   5. The method of manufacturing a droplet discharge head according to claim 4, wherein, in the peeling step, the flexible substrate is bent in a state where the predetermined position is selectively heated.   A droplet discharge apparatus comprising the droplet discharge head according to claim 1 or 2 or the droplet discharge head manufactured by the manufacturing method according to any one of claims 3 to 5.

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