JP2011187745A - Structure and method for mounting flexible board, and droplet discharge head and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mounting structure of a flexible board, wherein a connection part of the flexible board is conductively connected with an electrode formed in a narrow groove in easy and sure ways, and to provide a droplet discharge head. <P>SOLUTION: The flexible board 500 has one end side inserted into a groove and is electrically connected with an upper electrode film (electrode) 80 of a piezoelectric element 300 at a terminal 512. A folded section 513 is formed in the terminal 512 of the flexible board 500, wherein the folded section is ridge-folded to be folded along the width direction of the flexible board 500, the direction being oriented at substantially a right angle relative to the extension direction of a wiring pattern (conductive part) 510 formed on a lower surface 500A of the flexible board 500. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to mounting of a flexible substrate, and more particularly, to a configuration of a connection portion that connects a flexible substrate and an electrode.

A droplet discharge method (inkjet method) is known as one of methods for manufacturing a microdevice. In this droplet discharge method, a liquid containing a material for forming a device is formed into droplets and discharged from a droplet discharge head. For example, Patent Document 1 discloses an example of a technique related to a droplet discharge head (inkjet recording head). Patent Document 1
In the liquid droplet ejection head disclosed in the above, a drive circuit unit (IC driver) and a drive element (
Piezoelectric element) is connected by a wire bonding technique.

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 the nozzle openings provided in the droplet discharge head (nozzle pitch) Is preferably as small (narrow) as possible. Since a plurality of the piezoelectric elements are formed corresponding to the nozzle openings, if the nozzle pitch is reduced, the distance between the piezoelectric elements needs to be reduced according to the nozzle pitch. However, when the distance between the piezoelectric elements becomes small, it becomes difficult to connect each of the plurality of piezoelectric elements and the IC driver by a wire bonding technique.

For this reason, for example, Patent Document 2 describes a droplet discharge device in which an electrode of a piezoelectric element formed in a groove of a droplet discharge head and an IC driver are connected via a flexible substrate. According to the droplet discharge device disclosed in Patent Document 2, the end portion (connecting portion) of the flexible substrate that goes down in the depth direction of the groove is bent in a horizontal direction with a width of about 1 mm, and a piezoelectric element is obtained. The end of the flexible substrate is brought into surface contact with the electrodes of the electrodes.

JP 2000-127379 A JP 2008-263049 A

However, with the recent miniaturization of the droplet discharge head, the size of the electrode of the piezoelectric element and the size of the groove that exposes the electrode are being reduced. For this reason, in the method of connecting the end portion of the flexible substrate in surface contact with the electrode of the piezoelectric element as shown in Patent Document 2 described above, 1 mm so as to face the one surface of the electrode horizontally. It is extremely difficult to stably bend the end portion of the flexible substrate with the following width, and there is a concern of causing poor conduction.

Some aspects according to the present invention have been made in view of the above circumstances, and a connection portion of a flexible substrate can be easily and reliably connected to an electrode formed in a narrow groove. It is an object of the present invention to provide a flexible substrate mounting structure and a droplet discharge head.
It is another object of the present invention to provide a flexible substrate mounting method and a droplet discharge head manufacturing method in which a flexible substrate connection portion can be easily formed and can be electrically connected to an electrode formed in a narrow groove. And

In order to solve the above problems, some embodiments of the present invention provide the following flexible substrate mounting structure, flexible substrate mounting method, droplet discharge head, and manufacturing method thereof.
That is, the flexible substrate mounting structure of the present invention is a flexible substrate mounting structure in which the flexible substrate is electrically connected to the electrode formed on the bottom surface in the groove via a bonding material,
A refracted portion refracted along a width direction substantially perpendicular to the extending direction of the flexible substrate is formed at one end side of the flexible substrate, and the refracted portion is formed on a line forming a ridge line with respect to the electrode. It is characterized by being electrically connected.

According to the mounting structure of such a flexible substrate, compared to the case where surface contact is made by bringing the electrode into line contact and conducting on one line forming the ridge line of the refracting portion formed on one end side of the flexible substrate. Therefore, partial lifting and bending of the flexible substrate at the contact portion are suppressed. Thereby, electrical connection between the flexible substrate and the electrode can be reliably ensured.
In addition, by configuring the terminal portion of the flexible substrate with a refracting portion bent at an acute angle, for example, it becomes possible to reduce the size of the groove when applied to a droplet discharge head,
The droplet discharge head can be further downsized.

The bonding material is preferably made of an insulating resin. Thus, without using an expensive anisotropic conductive resin, the terminal portion and the electrode can be reliably conducted using a low-cost insulating resin, and a flexible substrate mounting structure can be realized at a low cost.

The inside of the groove is preferably further sealed with a resin material. Thereby, one end side of the flexible substrate including the terminal portion is more firmly fixed in the groove, and disconnection and peeling of the connection portion can be more reliably prevented even when external stress or the like is applied.

The end part which comprises the one end side of the said flexible substrate may protrude from the surface of the said resin material. When the end portion of the flexible substrate is exposed from the mold resin, the conductive portion formed on the lower surface of the flexible substrate is also exposed. And by connecting a sensor terminal such as a voltage measuring instrument to the exposed conductive part, for example, the connection state etc. from the outside is inspected even after the flexible substrate and the electrode are connected and hardened with resin. Is possible.

The liquid droplet ejection head of the present invention is characterized by including the flexible substrate mounting structure described above.

The flexible substrate mounting method of the present invention is a flexible substrate mounting method in which an electrode formed on a bottom surface in a groove and a flexible substrate are electrically connected via a bonding material,
A step of dipping a bonding material on one surface of the electrode, on one end side of the flexible substrate,
Forming a refracted portion refracted along a width direction substantially perpendicular to the extending direction of the flexible substrate; and pressing the ridge line of the refracted portion against one surface of the electrode by a pressing member to make a line contact; And a step of fixing with a material.

According to such a method for mounting a flexible substrate, a contact portion is formed on one line forming a ridge line of a refracting portion formed on one end side of the flexible substrate, as compared with a case where surface contact is made by bringing the electrode into line contact and conducting. In this case, partial lifting and bending of the flexible substrate are suppressed, and the flexible substrate and the electrode can be reliably conducted. In addition, by pressing the bent portion bent at an acute angle against the electrode, the bonding material formed on the electrode can be easily pushed away, and the conductive portion and the electrode can be reliably conducted by this bent portion.

It is preferable that the pressing member includes a blade-shaped tip portion having an angle substantially the same as the refraction angle of the refraction portion. As a result, the pressing pressure can be concentrated only on the contact portion, that is, the linear portion along the ridge line of the refracting portion, so that the flexible substrates can be joined with a small pressing force without damaging the flexible substrate.

It is also preferable that the step of forming the refracting portion is performed when the one end side of the flexible substrate is pressed against one surface of the electrode at the tip portion of the pressing member. As a result, the step of forming the refracting portion in advance becomes unnecessary, the manufacturing process can be further simplified, and the flexible substrate can be mounted at low cost.

The bonding material may be made of an ultraviolet curable resin, and may further include a step of irradiating the bonding material with ultraviolet rays to be cured in the vicinity of the refracting portion in contact with the electrode. By forming an acute refracting portion in the terminal portion of the flexible substrate, ultraviolet rays can be irradiated from both sides of the refracting portion toward the periphery of the contact portion between the ridge line of the refracting portion and the electrode without being blocked by the flexible substrate. . For this reason, it becomes possible to join the refracting part of the flexible substrate and the electrode quickly and without misalignment.

A manufacturing method of a droplet discharge head according to the present invention is characterized by including the flexible substrate mounting method described in the above items.

It is an external appearance perspective view which shows an example of the droplet discharge head provided with the flexible substrate mounting structure of this invention. It is the perspective view which looked at the droplet discharge head from the lower side. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1. It is the figure which looked at the flexible substrate from the lower surface side. It is a principal part expanded sectional view which shows the connection part of a flexible substrate and the electrode of a piezoelectric element. It is a principal part expanded sectional view which shows another example of the mounting structure of a flexible substrate. It is sectional drawing which shows the manufacturing method of the droplet discharge head provided with the mounting method of the flexible substrate of this invention. It is sectional drawing which shows the manufacturing method of the droplet discharge head provided with the mounting method of the flexible substrate of this invention. It is a principal part expanded sectional view which shows another example of the mounting method of a flexible substrate. It is a principal part expanded sectional view which shows another example of the mounting method of a flexible substrate.

DESCRIPTION OF EXEMPLARY EMBODIMENTS An embodiment of a flexible substrate mounting structure, a flexible substrate mounting method, a droplet discharge head, and a manufacturing method thereof will be described below with reference to the drawings. In addition, this embodiment is specifically described in order to make the gist of the invention better understood.
Unless otherwise specified, the present invention is not limited. In addition, in the drawings used in the following description, in order to make the features of the present invention easier to understand, there is a case where a main part is shown in an enlarged manner for convenience, and the dimensional ratio of each component is the same as the actual one. Not necessarily.

First, an outline of a droplet discharge head having a flexible substrate mounting structure according to the present invention will be described with reference to FIGS.
1 is an external perspective view showing an embodiment of a droplet discharge head, FIG. 2 is a partially broken view of the perspective view of the droplet discharge head as viewed from below, and FIG. 3 is a cross-sectional view taken along the line AA in FIG. FIG. 4 is a view of the flexible substrate as viewed from the lower surface side.

The droplet discharge head 1 discharges droplets of functional liquid (for example, ink), and is connected to a nozzle substrate 16 having a nozzle opening 15 from which droplets are discharged, and an upper surface of the nozzle substrate 16. A flow path forming substrate 10 that forms a flow path through which a droplet flows, a vibration plate 400 that is connected to the upper surface of the flow path forming substrate 10 and is displaced by driving of the piezoelectric element 300, and an upper surface of the vibration plate 400. Reservoir forming substrate 20 for forming reservoir 100 and reservoir forming substrate 2
Flexible substrate 500 provided on the upper surface side of 0 and flexible substrate 5
00 is provided on the lower surface 500A of the drive circuit 200 for driving the piezoelectric element 300, and the lower surface 500A of the flexible substrate 500 is provided on the lower surface 500A of the drive circuit unit 200.
And a conductive portion (conductive pattern, wiring pattern) 510 that electrically connects the piezoelectric element 300 to each other. The conductive pattern 510 is a wiring pattern made of a conductive material such as Cu (copper), for example, and has a thickness of several μm.

The operation of the droplet discharge head 1 is controlled by an external controller CT. The pressure generation chamber 12 in which the functional liquid before being discharged from the nozzle opening 15 is disposed is formed by a space surrounded by the flow path forming substrate 10, the nozzle substrate 16, and the vibration plate 400. . A reservoir 100 that preliminarily holds the functional liquid before being supplied to the pressure generating chamber 12 is formed by a space surrounded by the reservoir forming substrate 20 and the flow path forming substrate 10.

The lower surface side of the flow path forming substrate 10 is open, and the nozzle substrate 16 is connected to the lower surface of the flow path forming substrate 10 so as to cover the opening. The lower surface of the flow path forming substrate 10 and the nozzle substrate 16 are fixed via, for example, an adhesive or a heat welding film. The nozzle substrate 16 is provided with a nozzle opening 15 for discharging droplets.

As shown in FIG. 2, a plurality of nozzle openings 15 are provided in the nozzle substrate 16. Specifically, the nozzle substrate 16 includes a first nozzle opening group 15A, a second nozzle opening group 15B, and a third nozzle opening group 1 configured by a plurality of nozzle openings 15 provided side by side in the Y-axis direction.
Each of 5C and the fourth nozzle opening group 15D is provided. First nozzle opening group 15
A and the second nozzle opening group 15B are arranged to face each other in the X-axis direction. The third nozzle opening group 15C is provided on the + Y side of the first nozzle opening group 15A, and the fourth nozzle opening group 15D is provided on the + Y side of the second nozzle opening group 15B. The third nozzle opening group 15C and the fourth nozzle opening group 15D are arranged so as to face each other in the X-axis direction.

In FIG. 2, each of the nozzle opening groups 15 </ b> A to 15 </ b> D has six nozzle openings 15.
However, actually, for example, it is configured by about 720 nozzle openings 15.

A plurality of partition walls 11 are formed inside the flow path forming substrate 10. The flow path forming substrate 10 is formed of silicon, and the plurality of partition walls 11 are formed by anisotropically etching a silicon single crystal substrate that is a base material of the flow path forming substrate 10. And a plurality of partition walls 1
A plurality of pressure generating chambers 12 are formed by a space surrounded by the flow path forming substrate 10 having the nozzle 1, the nozzle substrate 16, and the vibration plate 400. The pressure generation chamber 12 includes a plurality of nozzle openings 15.
A plurality are formed so as to correspond to the above. That is, the pressure generating chamber 12 corresponds to the plurality of nozzle openings 15 constituting each of the first to fourth nozzle opening groups 15A to 15D.
A plurality are arranged side by side in the Y-axis direction.

A plurality of pressure generating chambers 12A corresponding to the first nozzle opening group 15A constitutes a first pressure generating chamber group 12A, and a plurality of pressure generating chambers 12 corresponding to the second nozzle opening group 15B are formed. Constitutes a second pressure generation chamber group 12B, and a plurality of pressure generation chambers 12 corresponding to the third nozzle opening group 15C constitutes a third pressure generation chamber group 12C, corresponding to the fourth nozzle opening group 15D. Thus, a fourth pressure generation chamber group 12D is configured by the plurality of pressure generation chambers 12 formed. The first pressure generation chamber group 12A and the second pressure generation chamber group 12B are arranged to face each other in the X-axis direction, and a partition wall 10K is formed between them. Similarly, the partition wall 1 is interposed between the third pressure generation chamber group 12C and the fourth pressure generation chamber group 12D.
0K is formed, and they are arranged so as to face each other in the X-axis direction. The flow path forming substrate 10 including the partition walls 10K may be formed of, for example, a silicon single crystal.

Of the plurality of pressure generating chambers 12 forming the first pressure generating chamber group 12A, the end on the −X side is closed by the partition wall 10K described above, but the end on the + X side is gathered so as to be connected to each other. And is connected to the reservoir 100. The reservoir 100 is introduced from the functional liquid introduction port 25 and temporarily holds the functional liquid before being supplied to the pressure generating chamber 12, and is formed on the reservoir forming substrate 20 so as to extend in the Y-axis direction. The reservoir portion 21 is formed on the flow path forming substrate 10 so as to extend in the Y-axis direction, and the communication portion 13 that connects the reservoir portion 21 and each of the pressure generating chambers 12 is provided. That is, the reservoir 100 is a functional liquid holding chamber (ink chamber) common to the plurality of pressure generating chambers 12 constituting the first pressure generating chamber group 12A. The functional liquid introduced from the functional liquid introduction port 25 flows into the reservoir 100 via the introduction path 26, and is supplied to each of the plurality of pressure generation chambers 12 constituting the first pressure generation chamber group 12A via the supply path 14. The

A reservoir 100 similar to that described above is also connected to each of the pressure generation chambers 12 constituting each of the second, third, and fourth pressure generation chamber groups 12B, 12C, and 12D.

The diaphragm 400 disposed between the flow path forming substrate 10 and the reservoir forming substrate 20 is provided on the elastic film 50 so as to cover the upper surface of the flow path forming substrate 10 and on the upper surface of the elastic film 50. And a lower electrode film 60. The elastic film 50 is made of, for example, silicon dioxide having a thickness of about 1 to 2 μm. The lower electrode film 60 is made of, for example, a metal having a thickness of about 0.2 μm. In the present embodiment, the lower electrode film 60 is a common electrode for the plurality of piezoelectric elements 300.

The piezoelectric element 300 for displacing the diaphragm 400 includes a piezoelectric film 70 provided on the upper surface of the lower electrode film 60 and an upper electrode film 80 provided on the upper surface of the piezoelectric film 70. The piezoelectric film 70 has a thickness of about 1 μm, for example, and the upper electrode film 80 has a thickness of about 0.1 μm, for example.

The concept of the piezoelectric element 300 may include the lower electrode film 60 in addition to the piezoelectric film 70 and the upper electrode film 80. That is, the lower electrode film 60 in the present embodiment is
It has both the function as the piezoelectric element 300 and the function as the diaphragm 400. Also,
In the present embodiment, the elastic film 50 and the lower electrode film 60 function as the diaphragm 400. However, the elastic film 50 may be omitted, and the lower electrode film 60 may also serve as the elastic film (50).

The piezoelectric film 70 and the upper electrode film 80, that is, the piezoelectric element 300 includes a plurality of nozzle openings 1.
5 and a plurality of pressure generation chambers 12 are provided so as to correspond to each. That is, the piezoelectric element 300 including the piezoelectric film 70 and the upper electrode film 80 is provided for each nozzle opening 15 (for each pressure generation chamber 12). As described above, the lower electrode film 60 functions as a common electrode for the plurality of piezoelectric elements 300, and the upper electrode film 80 functions as an individual electrode for the plurality of piezoelectric elements 300.

Further, the first piezoelectric element group 300A is provided by a plurality of piezoelectric elements 300 arranged in the Y-axis direction so as to correspond to each of the nozzle openings 15 constituting the first nozzle opening group 15A.
The second piezoelectric element group 300B is configured by a plurality of piezoelectric elements 300 arranged in the Y-axis direction so as to correspond to each of the nozzle openings 15 constituting the second nozzle opening group 15B. ing. The first piezoelectric element group 300A and the second piezoelectric element group 300B are arranged to face each other in the X-axis direction.

Similarly, a plurality of piezoelectric elements 300 arranged in the Y-axis direction so as to correspond to the respective nozzle openings 15 constituting the third and fourth nozzle opening groups 15C and 15D,
The fourth piezoelectric element group 300C, 300D is configured, and the third and fourth piezoelectric element groups 30 are configured.
0C and 300D are arranged so as to face each other in the X-axis direction (note that the third
The fourth piezoelectric element groups 300C and 300D are formed on the back side of the sheet of FIG.
Not shown).

A compliance substrate 30 having a sealing film 31 and a fixing plate 32 is bonded to the reservoir forming substrate 20. The sealing film 31 is made of a material having low rigidity and flexibility (for example, a polyphenylene sulfide film having a thickness of about 6 μm), and the upper part of the reservoir portion 21 is sealed by the sealing film 31. The fixing plate 32 is made of a hard material such as metal (for example, stainless steel having a thickness of about 30 μm). In the fixed plate 32, the region corresponding to the reservoir 100 is an opening 33 that is completely removed in the thickness direction, so that the upper portion of the reservoir 100 is formed only by the flexible sealing film 31. The flexible portion 22 is sealed and can be deformed by a change in internal pressure.

Normally, when the functional liquid is supplied to the reservoir 100 from the functional liquid inlet 25, a pressure change occurs in the reservoir 100 due to, for example, the flow of the functional liquid when the piezoelectric element 300 is driven or the ambient heat. However, as described above, the upper portion of the reservoir 100 is not sealed with the sealing film 31.
Therefore, the flexible part 22 is bent and deformed to absorb the pressure change. Therefore, the inside of the reservoir 100 is always maintained at a constant pressure. The other parts are held at a sufficient strength by the fixing plate 32.

On the compliance substrate 30 outside the reservoir 100, the reservoir 100
A functional liquid introduction port 25 for supplying functional liquid to the reservoir is formed, and the reservoir forming substrate 20 is provided with an introduction path 26 that communicates the functional liquid introduction port 25 with the sidewall of the reservoir 100.

A groove 700 extending in the Y-axis direction is formed in the central portion of the reservoir forming substrate 20 in the X-axis direction. By the groove portion 700, the reservoir forming substrate 20 is divided into a first sealing portion 20A for sealing the first piezoelectric element group 300A provided corresponding to the first pressure generating chamber group 12A, and a second pressure generating chamber group 12B. A second piezoelectric element group 300B provided correspondingly is sealed.
It is divided into a sealing portion 20B (see FIG. 3). Similarly, the groove portion 700 corresponds to the third sealing portion 20C for sealing the third piezoelectric element group 300C provided corresponding to the third pressure generation chamber group 12C and the fourth pressure generation chamber group 12D. The fourth piezoelectric element group 300D is sealed.
(The third and fourth sealing portions 20C and 20D are formed on the back side of the sheet of FIG. 3 and are not shown). And in the groove part 700,
A part of the flow path forming substrate 10 (partition wall 10K) is exposed.

That is, in the reservoir forming substrate 20, a region facing the piezoelectric element 300 is provided with the piezoelectric element holding portion 24 that can seal the space while ensuring a space that does not hinder the movement of the piezoelectric element 300. ing. The piezoelectric element holding part 24 includes first to fourth sealing parts 20A to 20.
It is formed in each of D, and is formed in a size that covers the first to fourth piezoelectric element groups 300A to 300D. Of the piezoelectric elements 300, at least the piezoelectric film 70 is sealed in the piezoelectric element holding portion 24.

As described above, the reservoir forming substrate 20 functions as a sealing member for sealing the piezoelectric element 300 by blocking the piezoelectric element 300 from the external environment. Reservoir forming substrate 20
By sealing the piezoelectric element 300 by the above, destruction of the piezoelectric element 300 due to an external environment such as moisture is prevented. Further, in the present embodiment, the inside of the piezoelectric element holding unit 24 is only sealed, but for example, by making the space in the piezoelectric element holding unit 24 vacuum or a nitrogen or argon atmosphere or the like, The inside of the piezoelectric element holding part 24 can be held at low humidity,
The destruction of the piezoelectric element 300 can be further reliably prevented.

The reservoir forming substrate 20 is a rigid body, and as the material for forming the reservoir forming substrate 20, for example, a material substantially the same as the coefficient of thermal expansion of the flow path forming substrate 10 such as glass or ceramic material is used. Preferably, in the present embodiment, a silicon single crystal substrate made of the same material as the flow path forming substrate 10 is used.

As shown in FIG. 3, in the piezoelectric element 300 sealed by the piezoelectric element holding part 24 of the first sealing part 20A, the end portion on the −X side of the upper electrode film 80 is the first sealing part 20A. The groove portion 700 is disposed on the flow path forming substrate 10. As shown in FIG. 3, in the case where a part of the lower electrode film 60 is disposed on the flow path forming substrate 10 in the groove portion 700, an electrical connection between the upper electrode film 80 and the lower electrode film 60 is performed. An insulating film 600 for preventing connection is provided between the upper electrode film 80 and the lower electrode film 60.

Similarly, the piezoelectric element 3 sealed by the piezoelectric element holding part 24 of the second sealing part 20B.
00, the + X side end of the upper electrode film 80 extends to the outside of the second sealing portion 20B, and is disposed on the flow path forming substrate 10 in the groove portion 700. Similarly, although not shown, the third
In the piezoelectric element 300 sealed with the fourth sealing portions 20C and 20D, a part of the upper electrode film 80 extends to the outside of the third and fourth sealing portions 20C and 20D. , The fourth sealing portion 20C
, 20D are disposed on the flow path forming substrate 10 in the groove 700 provided between the two.

The drive circuit unit 200 for driving the piezoelectric element 300 includes, for example, a circuit board or a semiconductor integrated circuit (IC) including a drive circuit, and is connected to the lower surface 500 </ b> A of the flexible substrate 500. The piezoelectric element 300 is driven by the drive circuit unit 200.
The flexible substrate 500 has flexibility, and is made of an insulating film member made of polyimide, for example. A conductive wiring pattern (conductive portion) 510 made of a conductive material such as copper is provided on the lower surface 500A of the flexible substrate 500 by a printing method or a method such as plating or etching.

As shown in FIG. 4, a drive circuit unit 200 is provided in a predetermined region of the lower surface 500 </ b> A of the flexible substrate 500. The drive circuit unit 200 includes a lower surface 500 of the flexible substrate 500.
A is flip-chip mounted on A and connected to a part of the wiring pattern 510. A plurality (four) of drive circuit units 200 are provided according to the first to fourth nozzle opening groups 15A to 15D. 1st-4th drive circuit part 2 provided according to the 1st-4th nozzle opening groups 15A-15D
Each of 00A to 200D is flip-chip mounted on the flexible substrate 500 and then fixed to the flexible substrate 500 by the resin 201.

An opening 520 is formed in part of the flexible substrate 500. Specifically, the opening 520 is in a region between the first drive circuit unit 200A and the second drive circuit unit 200B and a region between the third drive circuit unit 200C and the fourth drive circuit unit 200D. It is formed so as to extend in the Y-axis direction.

A resin (resin material: molding material) 202 is disposed between the flexible substrate 500 and the reservoir forming substrate 20, and the flexible substrate 500 and the reservoir forming substrate 20 are fixed by resin molding using the resin 202. Yes. Further, the resin 202 is also arranged inside the groove portion 700, and the terminal portion 512 and the piezoelectric element 300 (upper electrode film 80).
) And a resin molded part.

As shown in FIG. 4, notches 521 are formed at both ends in the Y-axis direction of the opening 520. Then, by the cutout portion 521, a partial region (edge region) 530 of the flexible substrate 500 that faces the opening 520 is bent inside the opening 520 (
Bend). The edge region 530 includes the drive circuit units 200A to 200A-2.
00D and the opening 520, which is an edge region 530 facing the opening 520
The edge portion 530E is substantially linearly formed along the Y-axis direction. That is, in the present embodiment, the edge region 530 is a rectangular region whose longitudinal direction is the Y-axis direction, and is bent so that the edge portion 530E rotates about the Y-axis (θY direction). ing.

Edge region 5 in opening 520 in lower surface 500 </ b> A of flexible substrate 500.
30 is formed with a terminal portion 512 constituting a part of the wiring pattern 510. In the first edge region 530A between the first drive circuit unit 200A and the opening 520, a plurality of terminal units 512 that are electrically connected to the first drive circuit unit 200A via the wiring pattern 510 are formed. . The plurality of terminal portions 512 provided in the first edge region 530A are connected to the first piezoelectric element group 3.
A plurality of piezoelectric elements 300 (upper electrode film 80) constituting 00A are connected to each of the plurality of piezoelectric elements 300 constituting the first piezoelectric element group 300A. (For example, 720) are provided side by side and constitute the first terminal group 512A. Therefore, when the terminal portion 512 and the piezoelectric element 300 are connected, the terminal portion 512 is connected.
The drive circuit unit 200 and the piezoelectric element 300 are electrically connected via a wiring pattern 510 including

Similarly, in the second edge region 530B between the second drive circuit unit 200B and the opening 520, a plurality (in the Y-axis direction (corresponding to the plurality of piezoelectric elements 300 constituting the second piezoelectric element group 300B) ( For example, 720) a second terminal group 512B including terminal portions 512 provided side by side is provided. The first edge region 530A and the second edge region 530B are arranged so as to face each other in the X-axis direction, and the first and second edge regions 530A, 53 are arranged.
The first terminal group 512A and the second terminal group 512B formed in each of the 0Bs are also configured to be opposed to each other in the X-axis direction.

Similarly, a third edge region 530 between the third drive circuit unit 200C and the opening 520 is used.
C includes a third terminal group 512 including a plurality of terminal portions 512 arranged in the Y-axis direction (for example, 720) so as to correspond to the plurality of piezoelectric elements 300 constituting the third piezoelectric element group 300C.
C is provided, and the fourth edge region 5 between the fourth drive circuit unit 200D and the opening 520 is provided.
30D includes a fourth terminal group 5 including a plurality of terminal portions 512 provided in a line in the Y-axis direction (for example, 720) so as to correspond to the plurality of piezoelectric elements 300 constituting the fourth piezoelectric element group 300D.
12D is provided. The third edge region 530C and the fourth edge region 530D are arranged so as to face each other in the X-axis direction.

When ejecting droplets of functional liquid from the droplet ejection head 1 having such a configuration, the external controller CT drives an external functional liquid supply device (not shown) connected to the functional liquid inlet 25.
The functional liquid sent from the external functional liquid supply device is stored in the reservoir 100 via the functional liquid inlet 25.
After being supplied to the nozzle opening 15, it fills the internal flow path of the droplet discharge head 1 up to the nozzle opening 15.
The external controller CT also includes an external signal input unit 5 provided on the flexible substrate 500.
Via 80, drive power and command signals are sent to the drive circuit section 200 and the like.

The flexible substrate 500 is provided with a wiring pattern 510, and a command signal or the like from the external signal input unit 580 is sent to the drive circuit unit 200 through the wiring pattern 510. Based on a command from the external controller CT, the drive circuit unit 200 is interposed between the lower electrode film 60 and the upper electrode film 80 corresponding to the pressure generation chamber 12 via the wiring pattern 510 including the terminal unit 512. A voltage is applied to displace the elastic film 50, the lower electrode film 60, and the piezoelectric film 70, thereby increasing the pressure in each pressure generating chamber 12 and ejecting droplets from the nozzle openings 15.

The configuration of the connection portion between the terminal portion 512 of the flexible substrate 500 and the electrode (upper electrode film 80) of the piezoelectric element 300, that is, the mounting structure of the flexible substrate 500 will be described in detail.
FIG. 5 is an enlarged cross-sectional view of a main part showing a connection portion between the flexible substrate and the electrode of the piezoelectric element.
One end of the flexible substrate 500 enters the groove portion 700 (see FIG. 1), and the terminal portion 5
12, the upper electrode film (electrode) 80 of the piezoelectric element 300 is electrically connected. The terminal portion 512 of the flexible substrate 500 has a flexible substrate 500 substantially perpendicular to the extending direction of the wiring pattern (conductive portion) 510 formed on the lower surface 500 </ b> A of the flexible substrate 500.
A refracting portion 513 is formed that is bent and refracted along the width direction (Y direction in FIG. 1).

The refracting portion 513 is, for example, 200 from the end portion E constituting one end side of the flexible substrate 500.
The wiring pattern (conductive portion) 510 is refracted so as to have a peak side with a width of ˜1000 μm. Then, on the lower surface 500 A side of the refracting portion 513, that is, on the side where the wiring pattern (conductive portion) 510 is formed, on the line forming the ridge line T of the refracting portion 513, the upper electrode film (electrode) 80 is in contact with and electrically connected. Is done. With such a connection structure, the flexible substrate 500 has a refracting portion 513 formed on one end side, and the width direction of the flexible substrate 500 (the Y direction in FIG. 1) with respect to the upper electrode film (electrode) 80 of the piezoelectric element 300. ) Along the line to be conducted.

The refraction angle (inner angle) θ1 of the refraction part 513 may be bent so as to be an acute angle, for example, in a range of 90 ° to 20 °. The smaller the internal angle θ1 of the refracting portion 513 is refracted, the more reliably the bonding material forming the bonding material layer 85 formed at the time of bonding is pushed away, and the conduction to the upper electrode film (electrode) 80 of the piezoelectric element 300 is surely made. Can be made. Further, as the inner angle θ1 of the refracting portion 513 is refracted, the size of the groove portion 700 can be reduced, which contributes to further downsizing of the droplet discharge head 1.

Further, a bonding material layer 85 in which a bonding material is dipped is formed on the upper electrode film (electrode) 80 of the piezoelectric element 300. The bonding material layer 85 is for bonding and fixing the terminal portion 512 of the flexible substrate 500 in line contact with the upper electrode film (electrode) 80 of the piezoelectric element 300 at the refracting portion 513 to the upper electrode film (electrode) 80. . As the bonding material constituting the bonding material layer 85, for example, a pre-feed type underfill material may be used, and a paste-like NCP (Non Conductive Polymer) is applied to one surface of the upper electrode film (electrode) 80 of the piezoelectric element 300. NCF (film-like NCF)
It is formed by pasting a non-conductive film. The bonding material constituting the bonding material layer 85 is, for example, an anisotropic conductive film (ACF: anisotropic) in addition to such an insulating resin.
An anisotropic conductive material including a conductive film) and an anisotropic conductive paste (ACP) can also be used.

According to the droplet discharge head 1 having such a mounting structure of the flexible substrate 500,
Compared with the case where surface contact is made by conducting line contact with the upper electrode film (electrode) 80 on one line forming the ridge line T of the refracting part 513 formed on one end side of the flexible substrate 500, compared with the case of surface contact. In this way, partial lifting and bending of the flexible substrate 500 are suppressed. Thereby, electrical connection between the flexible substrate 500 and the upper electrode film (electrode) 80 can be reliably ensured. In addition, by configuring the terminal portion 512 of the flexible substrate 500 with the refracting portion 513 bent at an acute angle, the size of the groove portion 700 of the droplet discharge head 1 can be reduced, and the droplet discharge head 1 can be reduced. It becomes possible to further reduce the size.

In the embodiment shown in FIG. 5 described above, the resin (resin material: mold material) 202 is entirely covered up to the end E forming one end of the flexible substrate 500. For example,
As in the embodiment shown in FIG. 6, the resin (resin material: mold material) 203 may be filled up to a level at which the end E forming one end of the flexible substrate 500 is exposed. When the end portion E of the flexible substrate 500 is exposed from the resin 203, the wiring pattern (conductive portion) 510 formed on the lower surface 500A of the flexible substrate 500 is also exposed. And even after the flexible substrate 500 and the upper electrode film (electrode) 80 are connected and hardened with the resin 203 by connecting a sensor terminal 800 such as a voltage measuring instrument to the exposed wiring pattern 510, It becomes possible to inspect the connection state from the outside.

Next, a manufacturing method of a droplet discharge head provided with the flexible substrate mounting method of the present invention will be described.
FIG. 7 and FIG. 8 are enlarged cross-sectional views of the main part showing stepwise the flexible substrate mounting process in the manufacturing method of the droplet discharge head.
When connecting the terminal portion of the flexible substrate and the upper electrode film (electrode) of the piezoelectric element, first, as shown in FIG. 7A, the lower surface 500A side of the flexible substrate 500, that is, the wiring pattern (conductive portion). For example, a bending jig 810 having a tip formed at an acute angle is pressed to one end side with the forming side of 510 facing down. Then, as shown in FIG. 7B, one end of the flexible substrate 500 is refracted from the end E of the flexible substrate 500 at a position of, for example, about 1000 μm following the bending jig 810. Thus, a refracting portion 513 that is bent and refracted along the width direction of the flexible substrate 500 (the Y direction in FIG. 1) is formed in the terminal portion 512 that forms one end of the flexible substrate 500.

Next, as shown in FIG. 7C, a bonding material made of, for example, NCP is dipped on one surface (upper surface) of the upper electrode film (electrode) 80 of the piezoelectric element 300 to form a bonding material layer 85. And
As shown in FIG. 8A, the refracting portion 513 formed in the terminal portion 512 of the flexible substrate 500.
The ridge line T of the refracting portion 513 and the upper electrode film (electrode) 80 are brought into line contact with each other so as to insert the ridge line T side into the bonding material layer 85.

At this time, for example, using the pressing member 820 provided with the blade-like tip 820a having the same angle as the refraction angle (inner angle) of the refracting portion 513, the tip 820a is pressed against the inner angle of the refracting portion 513. By pressing the flexible substrate 500 in this manner, for example, the NCP which is an insulating resin is pushed away, and the ridge line T of the refracting portion 513 is surely brought into contact with the upper electrode film (electrode) 80, and the wiring pattern (conductive portion) 510 and the upper Conduction with the electrode film 80 can be achieved.

Thereafter, as shown in FIG. 8B, the bonding material forming the bonding material layer 85 is cured to fix the refracting portion 513 of the flexible substrate 500 to the upper electrode film (electrode) 80. Furthermore, the groove 7
By filling resin (resin material: mold material) 202 in 00, the entire flexible substrate 500 is fixed.

According to the manufacturing method of the droplet discharge head 1 provided with the mounting method of the flexible substrate 500, the upper electrode film (electrode) is formed on one line forming the ridge line T of the refracting portion 513 formed on one end side of the flexible substrate 500. ) By making the line contact with 80 and conducting, it is possible to suppress partial lifting and bending of the flexible substrate 500 at the contact portion as compared with the case of surface contact, and the flexible substrate 500 and the upper electrode film (electrode) 80 can be reliably conducted. In addition, by pressing the bent portion 513 bent at an acute angle against the upper electrode film 80, the bonding material formed on the upper electrode film 80 can be easily pushed away, and the wiring pattern (conductive portion) 510 is connected to the bent portion 513. The upper electrode film 80 can be reliably connected. Further, the blade-shaped tip portion 820 having a sharp tip is provided.
By pressing the flexible substrate 500 using the pressing member 820 provided with a, the pressing pressure can be concentrated only on the contact portion, that is, the linear portion along the ridge line T of the refracting portion 513, so that flexible with a small pressing force. Bonding can be performed without damaging the substrate 500.

In the embodiment described above, the refraction part 513 is formed after the refraction part 513 is formed in advance.
Are joined to the upper electrode film (electrode) 80 of the piezoelectric element 300 in line contact with each other. The step of forming such a refracting portion is performed simultaneously with the bonding of the terminal portion of the flexible substrate to the upper electrode film (electrode). It is also preferable to do this. For example, in another embodiment shown in FIG.
A refracting portion is not formed in advance on one end of the piezoelectric element 300 and is pressed flat against the bonding material layer 85 formed on one surface (upper surface) of the upper electrode film (electrode) 80 of the piezoelectric element 300 (see FIG. 9A). ).

Then, as shown in FIG. 9 (b), this tip 820a is used by using a pressing member 820 having a blade-like tip 820a having substantially the same angle as the refraction angle (inner angle) of the refracting part to be formed.
Is pressed firmly against one end of the flat flexible substrate 500, and the terminal portion 512 of the flexible substrate 500 is in contact with the upper electrode film (electrode) 80 of the piezoelectric element 300, for example, 1000 μm from the end E of the flexible substrate 500. The flexible substrate 500 is refracted along the tip 820a of the pressing member 820 with a width.

As a result, the refracting portion 513 is formed in the terminal portion 512 of the flexible substrate 500, and at the same time, the wiring pattern (conductive portion) 510 and the upper electrode film 80 are brought into line contact at the ridgeline T of the refracting portion 513. . According to such a configuration, it is not necessary to separately provide a step of forming the refracting portion, and the flexible substrate and the electrode can be bonded more efficiently with fewer steps.

As a bonding material for bonding the refraction part 513 and the upper electrode film (electrode) 80 of the piezoelectric element 300,
For example, it is also preferable to use an ultraviolet curable resin. For example, in another embodiment shown in FIG. 10, an ultraviolet curable insulating resin is used for the bonding material layer 86 formed on one surface of the upper electrode film (electrode) 80 of the piezoelectric element 300. The ridge line T of the refracting portion 513 formed on the terminal portion 512 of the flexible substrate 500 and the upper electrode film (electrode) 80 are brought into contact with each other, and then the refracting portion 51 is formed.
3 is irradiated with ultraviolet rays UV toward the bonding material layer 86 made of an ultraviolet curable resin to be cured.

As described above, even when an ultraviolet curable resin is used for the bonding material layer 86, the refraction part 513 is formed by forming the acute refraction part 513 on the terminal part 512 of the flexible substrate 500.
UV rays can be irradiated from both sides to the periphery of the contact portion between the ridge line T of the refracting portion 513 and the upper electrode film (electrode) 80 without being blocked by the flexible substrate 500. Therefore, the refracting portion 513 of the flexible substrate 500 and the upper electrode film (electrode) 80 can be quickly joined without deviation.

DESCRIPTION OF SYMBOLS 1 ... Droplet discharge head, 15 ... Nozzle opening part, 15A-15D ... Nozzle opening group, 20 ...
Reservoir forming substrate (sealing member), 70 ... piezoelectric film (piezoelectric element), 80 ... upper electrode film (electrode)
, 85 ... bonding material layer (bonding material), 200 ... drive circuit section, 202 ... resin (resin material: molding material), 300 ... piezoelectric element (drive element), 300A, 300B ... piezoelectric element group (drive element group)
, 500 ... flexible substrate, 510 ... wiring pattern (conductive part), 512 ... terminal part, 51
3 ... Refraction part, 700 ... Groove part, 820 ... Pressing member.

Claims (10)

A flexible substrate mounting structure in which a flexible substrate is electrically connected to an electrode formed on a bottom surface in a groove via a bonding material,
On one end side of the flexible substrate, a refracted portion refracted along a width direction substantially perpendicular to the extending direction of the conductive portion formed on the flexible substrate is formed,
A flexible substrate mounting structure, wherein the flexible substrate is electrically connected to the electrode on one line forming a ridge line of the refracting portion. The flexible substrate mounting structure according to claim 1, wherein the bonding material is made of an insulating resin. The flexible substrate mounting structure according to claim 1, wherein the inside of the groove is further sealed with a resin material. 4. The flexible substrate mounting structure according to claim 3, wherein an end portion constituting one end side of the flexible substrate protrudes from a surface of the resin material. 5. A droplet discharge head comprising the flexible substrate mounting structure according to claim 1. A mounting method of a flexible substrate, wherein the electrode formed on the bottom surface in the groove and the flexible substrate are electrically connected via a bonding material,
Dipping a bonding material on one surface of the electrode;
Forming a refracted portion refracted along a width direction substantially perpendicular to the extending direction of the conductive portion formed on the flexible substrate on one end side of the flexible substrate;
Pressing the ridge line of the refracting portion against one surface of the electrode by a pressing member to make a line contact, and fixing with the bonding material;
A method for mounting a flexible substrate, comprising: The method for mounting a flexible substrate according to claim 1, wherein the pressing member includes a blade-shaped tip portion having an angle substantially the same as a refraction angle of the refraction portion. The method for mounting a flexible substrate according to claim 7, wherein the step of forming the refracting portion is performed when one end side of the flexible substrate is pressed against one surface of the electrode at a tip portion of the pressing member. 9. The bonding material is made of an ultraviolet curable resin, and further includes a step of irradiating the bonding material with ultraviolet rays and curing the bonding material in the vicinity of the refracting portion in contact with the electrode. The mounting method of the flexible substrate as described in 2. A method for manufacturing a droplet discharge head, comprising the flexible substrate mounting method according to claim 6.

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