JP2019001072A - Liquid discharge head and method for producing the same - Google Patents

Abstract

To provide a liquid discharge head with which application of sealing resin can be performed at low cost in a short time by a simple method, and the electric connection part of which has highly reliable insulating protection.SOLUTION: A liquid discharge head includes: a first electric wiring substrate 102; an element substrate 101 having a discharge port 101a discharging liquid and electrically connected to one end part of the first electric wiring substrate 102; and a second electric wiring substrate 105 electrically connected to the other end part of the first electric wiring substrate 102. The other end part of the first electric wiring substrate 102 and the second electric wiring substrate 105 are joined via a bonding member 106. The bonding member 106 has a planar shape including end parts 106a-106c located while protruding outward from the end parts 102a-102c of the first electric wiring substrate 102 at a joint part with the second electric wiring substrate 105 while viewed in a direction orthogonal to the plate surface of the second electric wiring substrate 105.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a liquid discharge head that discharges liquid and a method of manufacturing the same.

  A liquid discharge head that discharges liquid for image recording or the like has a discharge port disposed at a position facing the energy generation element, and discharges liquid from the discharge port to the outside by the energy generated by the energy generation element. is there. Such a liquid discharge head is called a side shooter type liquid discharge head. In general, the liquid discharge head is located away from the element substrate including the energy generating element, the electric wiring substrate including the electric wiring, the supporting member that supports the element substrate and the electric wiring substrate, and the supporting member. And an internal substrate. The electrical wiring substrate has one end connected to the element substrate and the other end connected to the internal substrate. Therefore, the electric power and electric signal transmitted from the liquid discharge head main body to the internal substrate of the liquid discharge head are transmitted from the internal substrate to the energy generating element of the element substrate via the electric wiring substrate.

  The electrical wiring board and the internal board are generally electrically connected by an anisotropic conductive film or wire bonding. When the electrical wiring board and the internal board are electrically connected by an anisotropic conductive film, the electrical pads on the electrical wiring board and the electrical pads on the internal board are aligned and placed between the two electrical pads. An anisotropic conductive film is placed and pressure bonded together. When the electrical wiring board and the internal board are electrically connected by wire bonding, for example, the respective electrical pads are connected by bonding wires in a state where the electrical wiring board is bonded onto the internal board.

  It is necessary to insulate and protect the electrical connection portion between the electrical wiring board and the internal board so as not to touch the liquid in order to prevent an electrical short circuit or corrosion. As a general insulation protection method, as described in Patent Document 1, a curable liquid sealing resin is applied and cured around the electrical connection portion and its periphery, and the electrical connection portion is embedded in the sealing resin. There is a way to wrap. Examples of the liquid sealing resin used here include an epoxy resin, an acrylic resin, a urethane resin, and a silicon resin having thermosetting, UV curable, or moisture curable properties. Insulating protection from the recording liquid is achieved by embedding an anisotropic conductive film or an electrical connection portion by wire bonding with these sealing resins. For reliable insulation protection, it is preferable to apply a sealing resin widely not only to the electrical connection portion but also to the periphery thereof. That is, unless a portion that may become a path for liquid or the like to enter the electrical connection portion is sealed with a sealing resin, it is not possible to sufficiently prevent the recording liquid or the like from entering the electrical connection portion.

JP 2007-313831 A

  In order to apply the sealing resin widely not only to the electrical connection part but also to the surroundings, the sealing resin is applied while rotating the electrical wiring board and the internal board in various postures while electrically connecting them. It is necessary to apply. However, it is not easy to perform coating while changing the postures of the connected electrical wiring board and internal board. Further, the time required for applying the sealing resin is long, and the lead time of the liquid discharge head is long. Further, a complicated mechanism is required to rotate the electric wiring board and the internal board, and the manufacturing cost of the liquid discharge head is increased.

  Accordingly, an object of the present invention is to provide a liquid discharge head capable of applying a sealing resin by a simple method in a low cost and in a short time, and having a high reliability of insulation protection of an electrical connection portion, and a manufacturing method thereof. It is in.

  The liquid discharge head according to the present invention includes a first electric wiring board, an element substrate having a discharge port for discharging liquid and electrically connected to one end of the first electric wiring board, and a first electric wiring board. A second electrical wiring board electrically connected to the other end of the wiring board, and the other end of the first electrical wiring board and the second electrical wiring board are connected via an adhesive member. The bonding member is bonded to the outside of the end portion of the bonding portion of the first electric wiring board with the second electric wiring board when viewed in the direction orthogonal to the plate surface of the second electric wiring board. It has a planar shape including an end portion that protrudes.

  According to the present invention, it is possible to apply the sealing resin by a simple method at a low cost and in a short time, and a liquid discharge head with high insulation protection of the electrical connection portion is realized.

FIG. 2 is a perspective view and a plan view of a main part of a liquid discharge head according to a first embodiment of the present invention. FIG. 2 is a plan view and a sectional view of a periphery of a joint portion between an electric wiring board and an internal board of the liquid ejection head shown in FIG. FIG. 7 is a perspective view illustrating a part of the manufacturing method of the liquid ejection head illustrated in FIG. 1. It is sectional drawing of the periphery of the junction part of the electrical wiring board of 2nd Embodiment, and an internal board | substrate. It is a top view of the periphery of the junction part of the electrical wiring board of 3rd Embodiment, and an internal board | substrate. FIG. 10 is a perspective view of a main part of a liquid discharge head according to a fourth embodiment, a plan view of a periphery of a joint portion between an electric wiring board and an internal board, and a plan view of a modification thereof.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1A is a perspective view showing a main part of a liquid discharge head according to the present invention, and FIG. 1B is a plan view thereof. FIG. 2A is a plan view of the joint portion of the electric wiring board and the internal substrate of FIG. FIG. 2B is a plan view showing a state where the electrical connection portion shown in FIG. 2A is covered with a sealing resin. FIG.2 (c) is the sectional view on the AA line of Fig.2 (a). FIG. 2D is a cross-sectional view of a comparative example for comparison with the configuration shown in FIG.
As shown in FIGS. 1A and 1B, a liquid discharge head according to this embodiment includes an element substrate (liquid discharge chip) 101, an electric wiring substrate (first electric wiring substrate) 102, and a support member. 103 and an internal substrate (second electrical wiring substrate) 105 which is another substrate. The element substrate 101 includes an ejection port 101a for ejecting a liquid such as a recording liquid (liquid ink), and an energy generation element (for example, a heating element or a piezoelectric element) disposed in a pressure chamber that is not illustrated but communicates with the ejection port. It has. The support member 103 supports one end portions of the element substrate 101 and the electric wiring substrate 102. The internal substrate 105 is disposed at a position away from the support member 103. The electrical wiring substrate 102 has electrical wiring (not shown) having one end connected to the element substrate 101 and the other end electrically connected to the internal substrate 105.

  In this liquid discharge head, the element substrate 101 and one end portion of the electric wiring substrate 102 are bonded on the support member 103. In the example shown in FIG. 1A, the element substrate 101 and one end portion of the electric wiring substrate 102 are electrically connected by wire bonding or the like (not shown), and are covered with the sealing resin 104 from above. Further, the other end portion of the electric wiring substrate 102 is bonded to the internal substrate 105. In the example shown in FIG. 1B, the electrical pad 107 at the other end of the electrical wiring substrate 102 is electrically connected to the electrical pad 112 of the internal substrate 105 by the bonding wire 108. However, the electrical connection method between the element substrate 101 and the electrical wiring substrate 102 and the electrical connection method between the internal substrate 105 and the electrical wiring substrate 102 are not limited to wire bonding. A known connection method using a flying lead, an anisotropic conductive film, an anisotropic conductive paste, or the like may be adopted to electrically connect them.

  The electrical connection portion between the electrical wiring substrate 102 and the element substrate 101 and the electrical connection portion between the electrical wiring substrate 102 and the internal substrate 105 need to be insulated and protected against recording liquid and moisture (humidity) in the air. In general, these electrical connection portions are insulated and protected by applying and hardening a curable liquid sealing resin. 1A and 1B, a sealing resin 104 that protects an electrical connection portion between the electrical wiring substrate 102 and the element substrate 101, and a seal that protects an electrical connection portion between the electrical wiring substrate 102 and the internal substrate 105 are shown. A stop resin 109 is shown. However, in order to illustrate the configuration around the joint portion between the electric wiring board 102 and the internal board 105, which is one of the features of the present invention to be described later, the sealing resin 109 in FIG. It is shown. Examples of the sealing resins 104 and 109 that cover the electrical connection portion include an epoxy resin, an acrylic resin, an epoxy acrylate resin, an imide resin, and an amide resin. The curing method of these sealing resins 104 and 109 may be any of two-component mixed curing in which a curing agent is mixed, thermal curing by heating, UV curing by ultraviolet irradiation, and the like. A wide variety of curing methods can be used in accordance with the above. The liquid sealing resin that is particularly preferably used is a thermosetting epoxy resin.

One end of the electric wiring board 102 and the element substrate 101 are bonded to the support member 103 by an adhesive (not shown). On the other hand, the other end portion of the electric wiring substrate 102 is bonded to the internal substrate 105 by an adhesive film 106 which is an example of an adhesive member. Examples of the adhesive film 106 include a film made of a curable resin composition and a film that exhibits an adhesive force by plastic deformation. Specifically, an adhesive film 106 made of a resin composition containing an epoxy resin, an imide resin, an amide resin, an acrylic resin, a urethane resin, or the like can be used. The adhesive film 106 includes a film that has tackiness from the beginning and a film that is heated to develop tackiness. Considering the ease of handling of the adhesive film 106, a film of a type that does not have adhesiveness at room temperature and exhibits adhesiveness when heated is convenient. As a method for joining the electric wiring substrate 102 and the internal substrate 105, a method using an adhesive or a double-sided tape in addition to the adhesive film 106 may be considered. Among these joining methods, taking into account the ease of the joining process, joining with an adhesive film or double-sided tape is simple. Of these, double-sided tapes are generally commercially available and inexpensive, but many have poor ink resistance. In particular, since the liquid discharge head is required to have resistance against the discharge liquid (for example, recording liquid ink), it is often preferable to use an adhesive film 106 of a type that exhibits adhesiveness by heating rather than a commercially available double-sided tape. .
As an example, in the liquid discharge head of this embodiment, the other end portion of the electric wiring substrate 102 is bonded to the internal substrate 105 via an adhesive film 106 made of a resin composition containing an epoxy resin. The adhesive film 106 does not have adhesiveness at room temperature, exhibits adhesiveness by heating and pressurizing, adheres to the adherend, and further heats to strengthen the adhesive force. Specific examples of the adhesive film 106 include FB-ML80 and FB-ML4 (both are trade names) manufactured by Nitto Denko Corporation, and FB-ML4 is used in this embodiment.

  As described above, in the present embodiment, the adhesive film 106 is interposed between the electric wiring board 102 and the internal board 105 and joins the electric wiring board 102 and the internal board 105. Then, the adhesive film 106 is viewed from the direction (Z direction) orthogonal to the plate surface (main surface) of the internal substrate 105 (as viewed in plan), and is the end of the joint portion of the electrical wiring substrate 102 with the internal substrate 105. It has a planar shape including an end portion that protrudes outside the portion. Specifically, in the width direction (X direction), both end portions 106a and 106b of the adhesive film 106 are positioned so as to protrude outward from both end portions 102a and 102b of the joint portion of the electrical wiring substrate 102 with the internal substrate 105. doing. That is, the length in the width direction of the adhesive film 106 is larger than the length in the width direction of the electric wiring substrate 102 when viewed in a direction perpendicular to the plate surface of the internal substrate 105. The width direction referred to here is a direction orthogonal to a direction extending from the central portion of the electric wiring board 102 toward the joint portion with the internal board 105 (referred to as a “direction in which the electric wiring board 102 extends (Y direction)” for convenience). It is. The width direction is the left-right direction of FIGS. 1 (b) and 2 (a). The extending direction of the electric wiring board 102 is the vertical direction of FIGS. 1 (b) and 2 (a). Further, in the extending direction of the electric wiring substrate 102, the tip end portion 102c of the joint portion of the electric wiring substrate 102 with the internal substrate 105 is located in an intermediate portion away from the end portion of the adhesive film 106, that is, the end portion 106c. Is located on the inside.

  Since the adhesive film 106 is arranged in this way, the adhesive film 106 is not completely covered by the electric wiring board 102. The end portions 106a to 106c of the adhesive film 106 are outside the three end portions (the width direction end portions 102a and 102b and the end portion 102c on the joining portion side) of the portion to be joined to the internal substrate 105 of the electric wiring board 102. Each protrudes. In this manner, with the electrical wiring substrate 102 bonded to the internal substrate 105 via the adhesive film 106, the electrical pads 107 of the electrical wiring substrate 102 and the electrical pads 112 of the internal substrate 105 are connected by the bonding wires 108. Yes. And this electrical connection part is covered with the sealing resin 109 as shown in FIG.2 (b). The adhesive film 106 is positioned between the region where the electric pads 107 of the electric wiring substrate 102 are formed and the internal substrate 105 when viewed in the direction perpendicular to the plate surface (Z direction).

By using such an adhesive film 106 and the sealing resin 109, it is possible to prevent a liquid such as a recording liquid from entering the electrical connection portion and to effectively insulate and protect the electrical connection portion. This point will be described in detail below.
As shown in FIGS. 1A, 1B, and 2A, in this embodiment, a part of the adhesive film 106 (D portion and E portion in FIG. 2A) is seen in a plan view. Protrudes outside the end of the electric wiring board 102. According to this configuration, as apparent from FIG. 2C, which is a cross-sectional view taken along the line AA in FIG. 2A, there is no gap into which the liquid can enter. That is, there is no space for holding liquid between the electrical wiring board 102 and the internal board 105. Therefore, there is a low possibility that the liquid will enter the joint portion (electric connection portion) between the electric wiring substrate 102 and the internal substrate 105.

Here, as shown in FIG. 2D, the comparative example in which the end portion of the adhesive film 106 does not protrude outside the end portion of the electric wiring substrate 102 and is located inside the end portion of the electric wiring substrate 102. To consider. In this comparative example, a gap B is generated between the electric wiring board 102 and the internal board 105 outside the adhesive film 106. With a general sealing resin, a sufficient amount of sealing resin cannot penetrate into the narrow gap B due to viscosity or fluidity, or a sufficient amount of the sealing resin enters the gap B to completely fill the gap B. It may not be possible. In such a case, the void B may remain without being blocked even after the sealing resin 109 is applied. Then, for example, the liquid is guided to the gap B along the back surface of the electric wiring substrate 102 at a position corresponding to the portion C in FIG. 2B (the outer edge portion of the sealing resin 109). Then, there is a possibility that the liquid accumulated in the gap B reaches the electrical connection portion between the electrical wiring board 102 and the internal board 105. Specifically, the liquid contacts the electrical pads 107 of the electrical wiring board 102, the electrical pads 112 of the internal board 105, and the bonding wires 108 extending between the electrical pads 107 and 112, causing an electrical short circuit and corrosion. There is a risk of causing. On the other hand, in the present embodiment, as shown in FIGS. 2A and 2C, the end portion of the adhesive film 106 protrudes outside the end portion of the electric wiring substrate 102. There is no gap B between the internal substrates 105, and liquid does not enter and accumulate. Therefore, there is a low possibility that the liquid reaches the electrical connection portion between the electric wiring substrate 102 covered with the sealing resin 109 and the internal substrate 105 and causes a problem such as an electrical short circuit.
Thus, in this embodiment, the edge part of the adhesive film 106 protrudes outside the edge part of the electrical wiring board 102. As a result, problems such as an electrical short circuit between the electrical wiring substrate 102 and the internal substrate 105 due to the penetration of liquid into the sealing resin 109 can be suppressed, and a liquid ejection head with high reliability of insulation protection can be obtained.

  In the method of manufacturing a liquid ejection head according to the present embodiment, a process of bonding the electric wiring substrate 102 to the internal substrate 105 using the adhesive film 106 will be described with reference to the perspective views of FIGS. 3 (a) to 3 (c). To do. First, as shown in FIG. 3A, an adhesive film 106 formed into a predetermined size by cutting or punching is placed on a predetermined position of the internal substrate 105. A separator film 113 made of resin is prepared above the adhesive film 106 (position facing the surface not in contact with the internal substrate 105). Next, the heating tool 114 is lowered from above the separator film 113 to heat the separator film 113 and the adhesive film 106, and pressurize it toward the internal substrate 105. As a result, the adhesive film 106 is fixed (thermocompression bonding) to the internal substrate 105. At this time, the separator film 113 prevents the heating tool 114 and the adhesive film 106 from being bonded.

As shown in FIG. 3B, the separator film 113 is removed and the electric wiring board 102 is placed on the adhesive film 106. Then, the heating tool 114 is lowered from above the electric wiring substrate 102 to heat the electric wiring substrate 102 and pressurize it toward the adhesive film 106 and the internal substrate 105. Thereby, the electric wiring board 102 is thermocompression bonded to the adhesive film 106. In this way, the electric wiring board 102 and the internal board 105 are bonded via the adhesive film 106. As described above, in the present embodiment, the end portions 106a to 106c of the adhesive film 106 protrude outward from the end portions 102a to 102c of the electric wiring board 102 located below the wire bonding 108 that is an electrical connection portion. Thereby, since the bonding area of the adhesive film 106 that contributes to the bonding between the electric wiring substrate 102 and the internal substrate 105 is large, a sufficient adhesive force can be obtained.
An electric pad 112 is formed on the inner substrate 105 at a position outside the adhesive film 106. An electrical pad 107 is formed on the surface of the electrical wiring substrate 102 opposite to the surface facing the internal substrate 105. After the internal substrate 105 and the electrical wiring substrate 102 are bonded, the electrical pads 107 of the electrical wiring substrate 102 and the electrical pads 112 of the internal substrate 105 are electrically connected by bonding wires 108 as shown in FIG. .

Next, in order to insulate and protect the wire bonding 108 and the electrical pad 107 which are electrical connection portions, as shown in FIG. 2B, a curable liquid sealing resin 109 is applied from above the electrical connection portions. Cover the electrical connections. At this time, a liquid sealing resin 109 is applied so as to cover the entire adhesive film 106 that protrudes outward from the end of the electric wiring substrate 102. By applying in this way, the electrical connection portion can be effectively insulated and protected from the recording liquid or the like. In this manner, the sealing resin 109 applied on the electric wiring substrate 102 and the internal substrate 105 including the electric connection portion is cured.
On the other hand, although not described in detail, as shown in FIGS. 1 (a) and 1 (b), the end of the electrical wiring board 102 opposite to the joint with the internal board 105 is used with an adhesive (not shown). It is fixed on the support member 103. Further, the element substrate 101 having a large number of discharge ports 101a is fixed to a position near the end of the electric wiring substrate 102 on the support member 103 using an adhesive (not shown). Although not shown, the electrical wiring board 102 and the element substrate 101 are electrically connected by wire bonding or the like. Further, a curable liquid sealing resin 104 is applied and cured from above the electrical connection portion so as to cover the electrical connection portion.

  As described above, the end portion of the electric wiring board 102 is electrically connected to the internal substrate 105, and the opposite end portion is electrically connected to the element substrate 101. In this way, the liquid discharge head of this embodiment can be formed. Note that the process of electrically connecting the end portion of the electrical wiring board 102 to the internal substrate 105 and the process of electrically connecting the opposite end portion to the element substrate 101 are performed first. It doesn't matter.

[Second Embodiment]
In the second embodiment of the present invention, the adhesive film 106 used for bonding the electric wiring substrate 102 and the internal substrate 105 is made of a material that dissolves in a liquid sealing resin. Specifically, as the adhesive film 106, DF470 (trade name) which is a thermal adhesive film manufactured by Hitachi Chemical Co., Ltd. is used. As the sealing resin 109, CV5300 (trade name), which is a fluid liquid sealing resin made of an epoxy resin composition manufactured by Panasonic Corporation, is used. Since the adhesive film 106 and the sealing resin 109 selected here are close in polarity, the adhesive film 106 is dissolved in the liquid sealing resin 109 during heating to thermally cure the liquid sealing resin 109 and is cured. The adhesive film 106 is taken into the stop resin 109. When the adhesive film 106 is dissolved and cured in a state of being taken into the liquid sealing resin 109 in this way, the interface between the adhesive film 106 and the sealing resin 109 disappears as shown in FIG. And more reliable bonding can be performed. In the present embodiment, the same configuration and method as those in the first embodiment are adopted except that the materials constituting the adhesive film 106 and the sealing resin 109 are selected as described above.

[Third Embodiment]
The third embodiment of the present invention employs a configuration that can achieve insulation protection of the electrical connection portion even when an error in the processing dimensions of the adhesive film 106 or a shift in the attachment position occurs. Specifically, in this embodiment, a sealing resin 109 similar to that of the first embodiment is used in combination with a low-viscosity sealing resin (another sealing resin) 110 shown in the plan view of FIG. Yes. The sealing resin 110 is disposed between the internal substrate 105 and the sealing resin 109. As in FIG. 1B, only the outline of the sealing resin 109 is shown by a two-dot chain line in FIG. The technical significance will be described below.
In the portion E or the like around the end portion of the electric wiring board 102 shown in FIG. It is conceivable that the end portion of the adhesive film 106 does not protrude. When the end portion of the adhesive film 106 does not protrude outward from the end portion of the electric wiring substrate 102, a void B in which liquid can be accumulated is generated as in the state shown in FIG. The reliability of insulation protection is reduced. Therefore, in the present embodiment, the low-viscosity sealing resin 110 shown in FIG. 5 is applied to the portion E (see FIG. 2A) around the end of the electric wiring board 102, and FIG. Even when the void B as shown is generated, the void B is filled with the low viscosity sealing resin 110. Since the sealing resin 110 has a low viscosity, it easily spreads by capillary force and is easily filled in the gap B. By filling the gap B with the low-viscosity sealing resin 110, for example, the liquid is applied to the back surface of the electrical wiring substrate 102 at a position corresponding to the portion C in FIG. 2B (the outer edge portion of the sealing resin 109). Accordingly, it is possible to suppress intrusion into the sealing resin 109. That is, the liquid path leading from the side of the adhesive film 106 to the electrical connection portion can be blocked by the low-viscosity sealing resin 110 and sealed. In addition, the viscosity of the low-viscosity sealing resin 110 in this embodiment is 0.1 to 100 Pa · s, and more preferably about 1 to 80 Pa · s. As an example, an epoxy resin sealing resin having a viscosity of 10 Pa · s is used. After the low-viscosity sealing resin 110 shown in FIG. 5 is applied to the periphery of the end portion of the electric wiring board 102 in this way, as in the first embodiment, A liquid sealing resin 109 is applied on the internal substrate 105 and cured. This embodiment is the same as the first embodiment regarding the configuration and method other than using the low-viscosity sealing resin 110.

[Fourth Embodiment]
The liquid ejection head of this embodiment has a configuration having a plurality of element substrates (liquid ejection chips) 101. For example, as shown in the perspective view of FIG. 6A, the six element substrates 101 are respectively bonded onto the support member 103 by an adhesive similarly to the element substrate 101 of the first embodiment. Further, each support member 103 is joined to a part (base block) 111 of the head casing by an adhesive. Further, the other end portions of the electric wiring substrate 102 whose one end portion is supported on each supporting member 103 and connected to each element substrate 101 are joined to one long internal substrate 105. The electrical wiring board 102 is bonded to the internal board 105 using the adhesive film 106 as in the first embodiment.

FIG. 6B is an enlarged plan view of a joint portion between the electric wiring board 102 and the internal board 105 in the present embodiment. As shown in FIG. 6B, the electric wiring substrate 102 is bonded to the internal substrate 105 by the adhesive film 106 as in the first embodiment. However, the end portion of the adhesive film 106 does not protrude outside the end portion of the electric wiring board 102 in the portion F around the end portion on the joint portion side in the extending direction of the electric wiring board 102. This is to prevent the adhesive film 106 from spreading over the electrical pads 112 of the internal substrate 105 when the electrical wiring substrate 102 is pressure-bonded onto the internal substrate 105. Explaining this point, when the end portion of the adhesive film 106 protrudes outside the end portion of the electric wiring board 102 as in the first embodiment, a sufficient adhesive force of the electric wiring board 102 can be obtained. . However, depending on the material of the adhesive film 106 and the conditions at the time of thermocompression bonding, the adhesive film 106 is softened at the time of thermocompression bonding and spreads excessively on the surface of the electrical wiring substrate 102 to cover a part of the electrical pads 112 of the internal substrate 105. The reliability of the electrical connection may be impaired. Therefore, in the present embodiment, the adhesive film 106 is arranged so that the position of the joint portion side end portion 106c of the adhesive film 106 matches the position of the end portion 102c of the electric wiring substrate 102 in the extending direction of the electric wiring substrate 102. ing. However, the adhesive film 106 is always present under the electric pad 107 of the electric wiring board 102 for wire bonding. This is because if the adhesive film 106 does not exist below the electric pad 107, a gap may be formed below the electric pad 107, and wire bonding may not be performed satisfactorily. Note that the adhesive film 106 may be disposed so that the joining portion side end portion 106c of the adhesive film 106 is positioned inside the end portion 102c of the electric wiring substrate 102 in the extending direction of the electric wiring substrate 102.
After joining the plurality of electrical wiring boards 102 to one internal board 105, as in the first embodiment, on the electrical wiring board 102 including the electrical connection portion and the end portions of the internal board 105 and the adhesive film 106, A curable liquid sealing resin 109 is applied and cured. In this way, the liquid discharge head of this embodiment having the six element substrates 101 is manufactured.

  In addition, in the modification of this embodiment shown in FIG.6 (c), application | coating of the sealing resin 109 is performed so that the edge part of the adhesive film 106 may be exposed like the part G. FIG. By applying the sealing resin 109 in this way, it is possible to suppress the usage amount of the sealing resin 109. If the adhesive film 106 has sufficient adhesive force, there is no problem even if a part of the adhesive film 106 is exposed in this way.

  As in this embodiment, in a liquid recording head having a plurality of liquid discharge chips 101, wire bonding is suitable as an electrical connection method when bonding a plurality of electrical wiring substrates 102 to one internal substrate 105. Yes. Of course, electrical connection by ILB (Inner Lead Bonding), OLB (Outer Lead Bonding), or ACF (anisotropic conductive film) is also possible. However, if a plurality of electrical wiring boards 102 are connected to one internal board 105, the positional relationship between the electrical pads 107 of each electrical wiring board 102 and the electrical pads 112 of the internal board 105 may increase. If the positions of the electric pad 107 and the electric pad 112 are greatly shifted, it may be impossible to electrically connect the two electric pads by ILB or OLB. On the other hand, in the case of electrical connection by wire bonding, a slight positional shift between the electric pad 107 and the electric pad 112 can be allowed, so that a plurality of electric wiring boards 102 are particularly bonded to one internal board 105. Is preferable.

As described above, according to the present invention, it is possible to reduce the risk of liquid such as discharge liquid entering the electrical connection portion between the electrical wiring board 102 and the internal board 105 and to suppress the occurrence of problems such as electrical short circuits. Can do. This effect is that, when viewed in a direction perpendicular to the plate surface of the internal substrate 105, the end portion of the adhesive film 106 protrudes outside the end portion of the joint portion of the electrical wiring substrate 102 with the internal substrate 105. Realized by. However, the configuration is not limited to a configuration in which all of the end portions of the adhesive film 106 protrude beyond the end portion of the joint portion of the electrical wiring substrate 102 with the internal substrate 105. A certain degree of effect can be obtained even in a configuration in which a part of the end portion of the adhesive film 106 protrudes outside the end portion of the joint portion of the electric wiring substrate 102 with the internal substrate 105.
Note that the configurations of the first to fourth embodiments described above can be arbitrarily combined.

101 Element substrate (liquid discharge chip)
102 Electrical Wiring Board 103 Support Member 104 Sealing Resin 105 Internal Board 106 Adhesive Film (Adhesive Member)
107 Electric pads (electrical connections)
108 Bonding wire (electrical connection)
109 Sealing resin 110 Low-viscosity sealing resin 112 Electrical pad (electrical connection part)

Claims (17)

A first electric wiring substrate; an element substrate having a discharge port for discharging a liquid; and electrically connected to one end of the first electric wiring substrate; and the other end of the first electric wiring substrate And a second electrical wiring board electrically connected to
The other end portion of the first electric wiring board and the second electric wiring board are bonded via an adhesive member,
The adhesive member protrudes outside the end portion of the joint portion of the first electric wiring board with the second electric wiring board when viewed in a direction perpendicular to the plate surface of the second electric wiring board. A liquid discharge head having a planar shape including an end portion located at a position.   In the width direction orthogonal to the direction of the first electric wiring board extending from the central portion toward the joint with the second electric wiring board, both end portions of the adhesive member are the first electric wiring board. 2. The liquid ejection head according to claim 1, wherein the liquid ejection head is located so as to protrude outward from both ends of a joint portion with the second electric wiring board.   In a direction extending from a central portion of the first electric wiring board toward a bonding portion with the second electric wiring board, the bonding portion of the first electric wiring board with the second electric wiring board 3. The liquid discharge head according to claim 1, wherein a position of a tip portion coincides with a position of an end portion of the adhesive member, or is located inside an end portion of the adhesive member.   An electric pad is formed on a surface of the second electric wiring board having a joint portion with the first electric wiring board, and a surface of the first electric wiring board facing the second electric wiring board. 2. An electrical pad is formed on a surface opposite to the first electrical wiring board, and the electrical pad of the second electrical wiring board is electrically connected to the electrical pad of the first electrical wiring board. 4. The liquid discharge head according to any one of items 1 to 3.   5. The liquid ejection head according to claim 4, wherein the electric pad of the second electric wiring board and the electric pad of the first electric wiring board are electrically connected by wire bonding.   6. The adhesive member is located between a region of the first electric wiring board where the electric pads are formed and the second electric wiring board when viewed in the orthogonal direction. The liquid discharge head described in 1.   An end portion of the adhesive member positioned outside an end portion of a joint portion of the first electric wiring board with the second electric wiring board; the electric pad of the second electric wiring board; and the first electric wiring board. The liquid ejection head according to claim 4, further comprising a sealing resin that covers an electrical connection portion of the electrical wiring board with the electrical pad.   Another sealing resin is provided in a portion where the part of the adhesive member does not protrude outside of the end portion of the joint portion between the first electrical wiring substrate and the second electrical wiring substrate. The liquid discharge head according to claim 7.   The liquid ejection head according to claim 8, wherein the another sealing resin has a viscosity lower than that of the sealing resin.   The liquid ejection head according to claim 8 or 9, wherein the viscosity of the another sealing resin is 0.1 to 100 Pa · s.   11. The liquid discharge head according to claim 7, wherein the adhesive member is melted and integrated in the sealing resin.   12. The liquid ejection head according to claim 1, wherein the adhesive member is an adhesive film that develops tackiness by heating.   The liquid discharge head according to claim 1, further comprising a sealing resin that covers an electrical connection portion between the first electric wiring board and the element substrate. A first electric wiring substrate; an element substrate having a discharge port for discharging a liquid; and electrically connected to one end of the first electric wiring substrate; and the other end of the first electric wiring substrate And a second electrical wiring board electrically connected to the liquid ejection head,
Bonding the other end of the first electrical wiring board and the second electrical wiring board via an adhesive member;
Electrically connecting the first electrical wiring board and the second electrical wiring board;
In the step of joining the other end portion of the first electric wiring board and the second electric wiring board, a part of the adhesive member as viewed in a direction orthogonal to the plate surface of the second electric wiring board The first electric wiring board and the second electric wiring board are positioned so as to protrude outward from the end portion of the joint portion of the first electric wiring board with the second electric wiring board. A method for manufacturing a liquid discharge head, wherein:   An end portion of the adhesive member located outside an end portion of a joint portion of the first electric wiring substrate with the second electric wiring substrate; the second electric wiring substrate; and the first electric wiring substrate. The method of manufacturing a liquid ejection head according to claim 14, further comprising: applying a liquid sealing resin so as to cover the electrical connection portion with the substrate, and then curing the resin.   The method of manufacturing a liquid ejection head according to claim 14, further comprising a step of electrically connecting the first electric wiring substrate to the element substrate.   The liquid discharge head according to claim 16, further comprising a step of applying a liquid sealing resin so as to cover the first electrical wiring substrate and the electrical connection portion between the element substrate and then curing the resin. Production method.

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