JP2018006530A - Connection structure, manufacturing method of connection structure, inkjet head and inkjet printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain conduction of wires of substrates even if an adhesive is expanded or shrunk in a configuration where the substrates are adhered by the adhesive, in such a manner that the wires of the substrates are brought into direct contact with each other.SOLUTION: A connection structure 1 includes a rigid substrate 11, a projected elastically deformable body 12, a first wire 13, a flexible substrate 21, a second wire 22 and an adhesive 31. The projected elastically deformable body 12 is positioned in a part of a surface of the rigid substrate 11 so as to protrude from the rigid substrate 11. At least a part of the first wire 13 is positioned on a surface 12a of the projected elastically deformable body 12 at a side opposite to the rigid substrate 11. The second wire 22 is positioned on the flexible substrate 21 and brought into direct contact with the first wire 13. The projected elastically deformable body 12 is elastically deformed in response to expansion or shrinkage of the adhesive 31 and held while being elastically deformed beforehand so as to maintain the contact between the first wire 13 and the second wire 22.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a connection structure in which a first substrate and a second substrate are bonded with an adhesive, a manufacturing method thereof, an inkjet head, and an inkjet printer.

  Conventionally, when bonding a first substrate (for example, a rigid substrate) on which a functional element (for example, a piezoelectric element) or wiring is formed and a second substrate (for example, a flexible substrate) on which another wiring is formed, A technique using an anisotropic conductive adhesive is known. An anisotropic conductive adhesive is an adhesive in which conductive particles are dispersed in a resin. For example, an anisotropic conductive film (ACF) or an anisotropic conductive paste (ACP) is used. It has been known. Examples of the conductive particles include metal-coated resin balls, solder particles, and nickel (Ni) particles.

  In adhesion using an anisotropic conductive adhesive, conductive particles are sandwiched between the wiring of the first substrate (including electrodes and bumps) on which the functional elements are formed and the wiring of the second substrate. Connect electrically. For this reason, the electroconductive particle should just be disperse | distributed uniformly in resin. Adhering the first substrate and the second substrate with the anisotropic conductive adhesive by melting the anisotropic conductive adhesive by heating and pressurizing with a crimping tool, and curing it by heat curing or ultraviolet curing. Can do.

  In recent years, with the increase in the density of functional elements, further finer pitches (narrower pitches and finer pitches) are required for the wiring pitch formed on the substrate. In the adhesion using the anisotropic conductive adhesive composed of ACF or ACP as described above, it is required to increase the filling rate by finely pulverizing the conductive particles for fine pitch, but when increasing the filling rate of the conductive particles, There is a concern that the conductive particles overlap each other, and the conductive particles aggregate between adjacent wirings to cause an electrical short circuit.

  Therefore, in Patent Document 1, for example, an anisotropic conductive sheet in which conductive particles and insulating particles having a specific gravity larger than that of conductive particles are dispersed in a resin is disposed between two substrates, and the above is performed by heating and pressing. The resin is melted to settle the insulating particles, and the molten resin is cured in a state where the density of the insulating particles is higher than the density of the conductive particles in the region near the electrode (wiring) on the lower substrate. The two substrates are bonded together. Since the resin is cured in a state where the insulating particles are allowed to settle, aggregation of conductive particles between adjacent wirings can be suppressed, and thereby an electrical short can be suppressed.

  By the way, when bonding two substrates with a conductive adhesive, the content of particles in the resin is generally 2.5 to 12.5% from the viewpoint of ensuring both conductivity and adhesion. It is necessary to be in the range. Incidentally, if the content is smaller than the lower limit (2.5%), it becomes difficult to ensure conductivity because the number of particles (particularly conductive particles) is reduced, and the content is upper limit (12.5%). If it exceeds, the number of particles will be excessive, and it will be difficult to ensure the adhesion by the resin. In the adhesive of Patent Document 1 containing conductive particles and insulating particles, it is assumed that the same particle content rate as described above is set in order to ensure conductivity and adhesion. However, it is considered that the upper limit of the content ratio of the particles needs to be set so that the total content ratio of the conductive particles and the insulating particles does not exceed the upper limit (12.5%) from the viewpoint of securing adhesiveness. .

  In any case, when two substrates are bonded using an adhesive containing conductive particles, a current flows only between the two substrates (between upper and lower wirings) where conductive particles exist. For this reason, the connection resistance between the two substrates increases, and as a result, the following inconvenience may occur. In other words, when a structure in which two substrates are bonded is applied to a device such as an ink jet head and a drive signal is supplied from one substrate to the other, the drive signal is delayed or a rectangular wave is trapezoidal, for example. For example, the drive signal is distorted. As a result, the device performance (for example, print quality) decreases.

  Thus, for example, Patent Document 2 discloses a connection structure in which two substrates are connected via a resin layer that substantially does not contain conductive particles. As the resin layer, for example, an insulating resin such as a non-conductive film (NCF) or a non-conductive paste (NCP) or a thermosetting insulating resin such as an epoxy resin or a silicone resin is used. ing. When the resin layer is used as an adhesive, the connection structure can be obtained by press-contacting both the substrates through the resin layer so that the wirings of both the substrates are in direct contact (contact).

  Thus, by using a resin layer not containing conductive particles as an adhesive, there is no concern that electrical shorting occurs due to the conductive particles, which is advantageous in reducing the wiring pitch. In addition, since the wirings on both the substrates are in direct contact with each other, the connection resistance between the two substrates can be greatly reduced, and it is considered that the above-described performance degradation of the device can be avoided.

JP 2008-306024 A (Claim 1, paragraphs [0013], [0033], [0048], FIG. 1A, FIG. 1B, FIG. 7, etc.) JP 2012-199262 A (refer to claim 3, paragraphs [0016], [0038], [0042], FIG. 2, etc.)

  Incidentally, the adhesive generally expands or contracts due to changes in environmental conditions such as temperature and humidity. For this reason, as in Patent Document 2, in the state where the wirings of both substrates are simply in contact with each other due to the adhesion of both substrates with an adhesive, the electrical connection between the wirings occurs when the state of the adhesive changes. The problem arises that it becomes impossible to maintain the value. That is, for example, when the adhesive expands in a high-temperature environment or a high-humidity environment, each substrate receives a force in a direction away from each other due to the expansion, so that the upper and lower wirings are separated from each other. After that, even if the adhesive shrinks due to a change in temperature or humidity, if the degree of shrinkage is weak, the upper and lower wirings will not return to their original contact positions. In either case, the continuity between the wirings of each substrate cannot be maintained.

  The present invention has been made in order to solve the above-described problems. The purpose of the present invention is to bond each substrate with an adhesive so that the wirings of each substrate are in direct contact with each other. Provided are a connection structure capable of maintaining electrical connection between wirings of each substrate even when contracted, a manufacturing method thereof, an ink jet head provided with the connection structure, and an ink jet printer provided with the ink jet head. There is.

  A connection structure according to one aspect of the present invention includes a first substrate and a second substrate that are opposed to each other, and an adhesive that bonds the first substrate and the second substrate. A convex elastic deformation body which is located directly or via a metal layer on the surface of the first substrate and protrudes toward the second substrate; and the convex elastic deformation body. A first wiring at least partially located on a surface opposite to the first substrate; and a second wiring located on the second substrate and in direct contact with the first wiring. In addition, the convex elastic deformation body is elastically deformed in advance so as to be elastically deformed in response to expansion or contraction of the adhesive and maintain contact between the first wiring and the second wiring. In this state, it is held between the first substrate and the second substrate.

  According to another aspect of the present invention, there is provided a method for manufacturing a connection structure, wherein a convex elastic deformation body projecting toward a part of a surface of a first substrate, directly or via a metal layer, toward the second substrate side. Forming an elastic deformation body, and forming a first wiring so that at least a part of the convex elastic deformation body is located on a surface opposite to the first substrate. Crimping which makes the 1st wiring and the 2nd wiring contact directly by crimping the 2nd substrate in which the 2nd wiring was formed on the surface to the 1st substrate via adhesives And the convex elastic deformation body is elastically deformed in response to expansion or contraction of the adhesive to maintain contact between the first wiring and the second wiring. As described above, the first elastic deformation body is elastically deformed in advance by pressure bonding. Held between the substrate and the second substrate.

  According to the connection structure and the manufacturing method therefor, the first substrate and the second substrate are bonded (crimped) with an adhesive, whereby the first wiring and the second substrate of the first substrate are bonded. The second wiring is in direct contact. At this time, at least part of the first wiring is located on the surface of the convex elastic deformation body. The convex elastic deformable body is elastically deformed in response to the expansion or contraction of the adhesive, and the first elastically deformed state is maintained in advance so as to maintain the contact between the first wiring and the second wiring. It is held between the substrate and the second substrate. Thereby, even if an adhesive expand | swells or shrink | contracts, the continuity between the wiring of each board | substrate can be maintained by the elastic deformation of an elastic deformation body. In particular, since the elastic deformable body is held in a state of being elastically deformed in advance, the elastic deformable body is extended in a direction in which the elastic deformable body is extended from the state of being elastically deformed in advance or contracted in accordance with the expansion or contraction of the adhesive. It can be elastically deformed, whereby the contact between the first wiring and the second wiring can be maintained.

  Furthermore, since the elastic deformable body is convex and there is no member that inhibits the elastic deformation of the elastic deformable body around the elastic deformable body, the elastic deformable body is freely elastically deformed according to the expansion or contraction of the adhesive. It becomes possible.

  Therefore, even if the adhesive expands or contracts, the conduction between the wirings between the first substrate and the second substrate can be maintained by elastic deformation with a high degree of freedom of the convex elastic deformation body. it can.

  The convex elastic deformation body is expanded by a restoring force from a state of being elastically deformed in advance when the adhesive is expanded, and is contracted when the adhesive is contracted, whereby the first wiring and the second wiring are You may maintain contact. By utilizing the expansion and contraction of the elastically deformable body from the state of being elastically deformed in advance, the contact between the wirings between the first substrate and the second substrate, both during expansion and contraction of the adhesive, and Conductivity can be reliably maintained.

  The surface of the convex elastic deformation body opposite to the first substrate may include a plane parallel to the first substrate. In the elastic deformation body forming step, the convex elastic body is formed such that a surface of the convex elastic deformation body opposite to the first substrate is a plane parallel to the first substrate. A deformation body may be formed. When the surface of the convex elastic deformable body includes a flat surface, the first wiring located on the surface is also flat. In the configuration having such a planar first wiring, the above-described effects can be obtained.

  The surface of the convex elastic deformable body opposite to the first substrate may include a convex surface on the opposite side of the first substrate. In the elastic deformable body forming step, the surface of the convex elastic deformable body opposite to the first substrate is a convex surface opposite to the first substrate. The convex elastic deformation body may be formed.

  If there is a convex surface on the surface of the convex elastic deformable body, the first wiring located thereon also has a convex shape. In this case, when the second substrate is pressure-bonded to the first substrate via the adhesive, it exists between the first wiring located on the elastic deformable body and the second wiring of the second substrate. The adhesive to be pressed can be pressed while being pushed out by the convex shape of the first wiring, and the biting of the adhesive between the two wirings can be reduced. As a result, it is possible to avoid a decrease in the contact area between the two wirings due to the biting of the adhesive and an increase in the connection resistance between the two substrates. Therefore, for example, when the connection structure having the above configuration is applied to a device, it is possible to avoid a decrease in the performance of the device due to the increase in the connection resistance.

  The convex elastic deformation body may be located on the first substrate such that the first wiring extends in parallel with a direction extending along the first substrate. The convex elastic deformation body may be positioned on the first substrate such that the first wiring extends in a direction intersecting with a direction extending along the first substrate. Thus, the above-described effect can be obtained in the configuration in which the convex elastic deformation body is located on the first substrate. In particular, the convex elastic deformation body may be positioned on the first substrate so as to be separated between the adjacent first wirings. In this case, the above-described effects can be efficiently obtained with a small amount of the elastic deformation body as compared with the configuration in which the convex elastic deformation body is formed also between the adjacent first wirings.

  In the connection structure and the manufacturing method thereof, the first substrate may be a rigid substrate, and the second substrate may be a flexible substrate. As described above, the above-described effects can be obtained in a configuration in which a rigid substrate is used as the first substrate and a flexible substrate is used as the second substrate.

  In the connection structure and the manufacturing method thereof, the adhesive may be a non-conductive adhesive. The nonconductive adhesive may be a nonconductive film or a nonconductive paste. Since these non-conductive adhesives do not include conductive particles for ensuring electrical continuity like conductive adhesives, there is no concern that electrical shorts due to conductive particles occur between adjacent wirings. Therefore, the first wiring and the second wiring can be formed with a narrow pitch (fine pitch).

  An ink jet head according to still another aspect of the present invention includes the connection structure described above, and the first substrate of the connection structure includes a support substrate on which a pressure chamber for containing ink is formed, and the pressure chamber. And a nozzle substrate having nozzle holes for discharging ink from the nozzle substrate.

  The ink in the pressure chamber of the support substrate included in the connection structure is ejected to the outside through the nozzle holes of the nozzle substrate. In the ink jet head having such a configuration, by using the connection structure described above, even if the adhesive expands or contracts, the conduction between the wirings between the first substrate and the second substrate is maintained. Therefore, a highly reliable inkjet head can be realized.

  The inkjet head further includes a lower electrode, a piezoelectric body, and an upper electrode in this order from the first substrate side, and the upper electrode is connected to the first wiring of the connection structure. Good. In this configuration, it is possible to drive (stretch) the piezoelectric body by applying a driving voltage to the upper electrode via the second wiring and the first wiring. In such an ink jet head, even if the adhesive expands or contracts due to a change in use environment (temperature, humidity, etc.), the connection structure described above is used, so that the first substrate and the second substrate It is possible to maintain the electrical connection between the wirings. For this reason, the piezoelectric body can be appropriately driven according to the drive voltage regardless of changes in the use environment.

  An ink jet printer according to still another aspect of the present invention includes the ink jet head described above, and ejects ink from the ink jet head toward a recording medium. By providing the above-described inkjet head, a highly reliable inkjet printer can be realized.

  According to the connection structure and the manufacturing method thereof, in the configuration in which the substrates are bonded with an adhesive so that the wirings of the substrates are in direct contact with each other, even if the adhesive expands or contracts, the convex elasticity Due to the elastic deformation with a high degree of freedom of the deformable body, the continuity between the wirings of the respective substrates can be maintained.

It is sectional drawing which shows the structure of the outline of the connection structure which concerns on one Embodiment of this invention. It is sectional drawing which shows the manufacturing process of the said connection structure. It is sectional drawing which shows the manufacturing process of the said connection structure. It is sectional drawing which shows the manufacturing process of the said connection structure. It is sectional drawing which shows the manufacturing process of the said connection structure. It is sectional drawing which shows typically the state of the said connection structure before and behind the crimping | compression-bonding of the flexible substrate to a rigid board | substrate. It is sectional drawing which shows the other structure of the said connection structure. It is a top view which shows an example of the formation pattern of an elastic deformation body. It is A-A 'arrow sectional drawing in FIG. 8A. It is a top view which shows the other example of the formation pattern of an elastic deformation body. FIG. 9B is a cross-sectional view taken along line B-B ′ in FIG. 9A. It is a top view which shows the further another example of the formation pattern of an elastic deformation body. FIG. 10B is a cross-sectional view taken along line C-C ′ in FIG. 10A. It is sectional drawing of the connection structure which crimped | bonded the flexible substrate to the rigid board | substrate of FIG. 10A. It is a top view which shows the further another example of the formation pattern of an elastic deformation body. FIG. 11B is a cross-sectional view taken along line D-D ′ in FIG. 11A. It is sectional drawing of the connection structure which crimped | bonded the flexible substrate to the rigid board | substrate of FIG. 11A. It is a top view which shows the schematic structure of an inkjet head. It is E-E 'arrow sectional drawing in FIG. 12A. It is F-F 'arrow sectional drawing in FIG. 12A. 10B is a part of a cross-sectional view taken along line G-G ′ in FIG. 10A. It is explanatory drawing which shows the schematic structure of an inkjet printer.

  An embodiment of the present invention will be described below with reference to the drawings. In the present specification, when the numerical range is expressed as A to B, the numerical value range includes the values of the lower limit A and the upper limit B.

[Configuration of connection structure]
FIG. 1 is a cross-sectional view showing a schematic configuration of a connection structure 1 of the present embodiment. The connection structure 1 includes a rigid substrate 11 (first substrate), a flexible substrate 21 (second substrate), and an adhesive 31.

  The rigid substrate 11 is a rigid substrate, and is composed of, for example, a semiconductor substrate made of single crystal Si (silicon) alone, an SOI (Silicon on Insulator) substrate, a glass substrate, or a combination thereof. The SOI substrate is obtained by bonding two Si substrates through an oxide film. The flexible substrate 21 is a flexible substrate and is disposed to face the rigid substrate 11. The flexible substrate 21 is made of a resin film such as polyimide, for example. The adhesive 31 is an adhesive that bonds the rigid substrate 11 and the flexible substrate 21. For example, a non-conductive adhesive (thermosetting insulation) such as a non-conductive film (NCF) or a non-conductive paste (NCP). Resin).

  The connection structure 1 further includes an elastic deformable body 12, a first wiring 13, and a second wiring 22. A plurality of elastic deformation bodies 12 are provided on a part of the surface of the rigid substrate 11 directly or via a metal layer so as to protrude from the rigid substrate 11 toward the flexible substrate 21, and the cross-sectional shape thereof is the rigid substrate 11. It is convex from the side toward the flexible substrate 21 side. Each elastic deformable body 12 is positioned away from each other on the rigid substrate 11.

  In addition, what is necessary is just to provide said metal layer as needed. For example, when the connection structure 1 of this embodiment is applied to an inkjet head described later, the metal layer can be provided as a lower electrode of a piezoelectric element that is a functional element.

  The elastic deformable body 12 is made of, for example, a photosensitive material made of polyimide resin or a parylene resin. However, the elastic deformable body 12 may be made of any material as long as it is elastically deformed according to the expansion or contraction of the adhesive 31. May be. The surface 12 a opposite to the rigid substrate 11 in the elastic deformation body 12 includes a plane parallel to the rigid substrate 11, for example.

  A plurality of first wirings 13 are provided, and at least a part of the first wiring 13 is located on the surface 12 a of the convex elastic deformation body 12. Therefore, as shown in the figure, the entire first wiring 13 may be located on the surface 12a of the elastic deformable body 12, or only a part of the first wiring 13 is elastic as will be described later. It may be located on the surface 12a of the deformable body 12 (the remainder of the first wiring 13 may be located on the rigid substrate 11). When the surface 12a of the elastic deformation body 12 is a flat surface, the first wiring 13 is formed in a planar shape along the surface 12a on the surface 12a. The first wiring 13 may be made of a conductive metal material such as aluminum (Al), titanium (Ti), platinum (Pt), nickel (Ni), gold (Au), and has a single layer structure. There may be a laminated structure.

  The second wirings 22 are located at a plurality of locations on the flexible substrate 21 in patterns corresponding to the first wirings 13 and are in direct contact with the first wirings 13. Similarly to the first wiring 13, the second wiring 22 may be made of a conductive metal material such as Al, Ti, Pt, Ni, Au, or may have a single layer structure. A laminated structure may be used.

  The convex elastic deformable body 12 described above is elastically deformed according to the expansion or contraction of the adhesive 31 so that the contact between the first wiring 13 and the second wiring 22 can be maintained in advance. It is held between the rigid substrate 11 and the flexible substrate 21 in an elastically deformed state. Thereby, even if the adhesive 31 expands or contracts due to an environmental change such as a temperature change or a humidity change, the conduction between the first wiring 13 and the second wiring 22 can be maintained.

  That is, for example, when the adhesive 31 expands in a high-temperature environment or a high-humidity environment, the rigid substrate 11 and the flexible substrate 21 sandwiching the adhesive 31 move in a direction away from each other. At this time, the elastic deformable body 12 extends in a direction in which the first wiring 13 is displaced toward the flexible substrate 21 by a restoring force from a state in which the elastic deformable body is elastically deformed in advance. For this reason, even if the rigid substrate 11 and the flexible substrate 21 are about to be separated from each other, the contact between the first wiring 13 and the second wiring 22 can be maintained by the extension of the elastic deformation body 12. On the other hand, when the adhesive 31 contracts due to an environmental change from a high temperature to a low temperature or the like (to return to the original state), the rigid substrate 11 and the flexible substrate 21 move in a relatively approaching direction, and the first wiring 13 and the first wiring 13 The second wiring 22 comes into contact (contact). At this time, stress (pressing force) from the second wiring 22 is applied to the first wiring 13, but the elastic deformable body 12 displaces the first wiring 13 toward the rigid substrate 11 by the stress. Since it shrinks in the direction, the first wiring 13 and the second wiring 22 can be brought into contact with each other with an appropriate pressing force, and the contact can be maintained.

  In particular, since the elastic deformable body 12 is held in an elastically deformed state in advance, the direction in which the elastic deformable body 12 extends from the elastically deformable body 12 based on the preliminarily elastically deformed state according to the expansion or contraction of the adhesive 31. In addition, it can be elastically deformed in the shrinking direction, and thereby the contact between the first wiring 13 and the second wiring 22 can be maintained. As a result, even if the adhesive 31 expands or contracts, conduction between the first wiring 13 and the second wiring 22 can be maintained.

  Further, since the elastic deformation body 12 is convex, there is no member that inhibits the elastic deformation of the elastic deformation body 12 around the elastic deformation body 12 (between adjacent elastic deformation bodies 12 and 12). For this reason, the convex elastic deformable body 12 is freely elastic in the direction in which the first wiring 13 is advanced and retracted (direction perpendicular to the rigid substrate 11) as described above in accordance with the expansion or contraction of the adhesive 31. It becomes possible to deform. Note that an adhesive 31 exists around the convex elastic deformable body 12. The adhesive 31 acts to stretch the elastic deformable body 12 when expanded, and elastic when contracted. It acts to shrink the deformable body 12. That is, the adhesive 31 around the elastic deformable body 12 acts in a direction that promotes elastic deformation of the elastic deformable body 12. Therefore, the adhesive 31 cannot be a member that inhibits the elastic deformation of the elastic deformable body 12.

  As described above, even when the adhesive 31 expands or contracts, the conduction between the first wiring 13 and the second wiring 22 is maintained by the above-described elastic deformation with a high degree of freedom of the convex elastic deformation body 12 ( Can be stabilized).

  Further, the convex elastic deformation body 12 is extended by a restoring force from a state of being elastically deformed in advance when the adhesive 31 is expanded, and is contracted when the adhesive 31 is contracted. In this way, by utilizing the expansion and contraction of the elastic deformable body 12 from the previously elastically deformed state, the first wiring 13 and the second wiring 22 are both expanded and contracted. Contact and conduction can be reliably maintained.

  Further, even when the height (thickness) varies between the first wiring 13 and the second wiring 22, the convex elastic deformation body 12 can be elastically deformed to absorb the variation, These electrical connections can be stabilized. The adhesive 31 is a non-conductive adhesive (thermosetting resin) and does not contain conductive particles, so it is effective in preventing short circuit between the adjacent first wirings 13 and 13. It is also possible to easily achieve fine pitch. Such a fine pitch realizes a high-density arrangement of elements (piezoelectric elements) connected to the first wiring 13 in a device such as an inkjet head described later, and can draw a high-definition image with a small configuration. This is very advantageous. Further, since the first wiring 13 and the second wiring 22 are in direct contact without passing through the conductive particles, the connection resistance between the rigid substrate 11 and the flexible substrate 21 can be greatly reduced, and the connection resistance can be reduced. It is also possible to avoid a decrease in device performance due to the increase.

[Method of manufacturing connection structure]
Next, the manufacturing method of the connection structure 1 mentioned above is demonstrated based on FIGS. 2-5 is sectional drawing which shows the manufacturing process of the connection structure 1 of this embodiment. The manufacturing method of the connection structure 1 of this embodiment includes an elastic deformation body forming step, a wiring forming step, and a crimping step.

(Elastic deformation body formation process)
In the elastic deformable body forming step, a convex elastic deformable body 12 protruding from the rigid substrate 11 toward the flexible substrate 12 is formed on a part of the surface of the rigid substrate 11. More specifically, it is as follows. Here, as an example, the case where the elastic deformation body 12 is directly formed on a part of the surface of the rigid substrate 11 will be described. However, the elastic deformation body 12 is formed via a metal layer (corresponding to a lower electrode described later). May be. In this case, for example, after forming a metal layer on the entire surface of the rigid substrate 11, the elastic deformable body 12 may be formed on a part of the surface of the metal layer.

  First, as shown in FIG. 2, the elastic deformation body 12 is formed on the entire surface of the rigid substrate 11 (S1). Here, a Si substrate is used as the rigid substrate 11. The Young's modulus of Si is about 65 GPa, and the total thickness of the Si substrate is about 500 μm. As the elastic deformable body 12, here, a photosensitive material made of polyimide resin (for example, TMMR series manufactured by Tokyo Ohka Kogyo Co., Ltd.) is used, and the photosensitive material (liquid material) is applied onto the rigid substrate 11 with a spin coater or the like. . The Young's modulus of the polyimide resin is about 5 GPa, and the thickness before pressure bonding is about 4 μm. In addition, you may comprise the elastic deformation body 12 with parylene resin. When the parylene resin is used, the elastic deformable body 12 can be formed by vacuum deposition.

  The film thickness of the elastic deformation body 12 is preferably about 2 to 15 μm, for example. In such a thickness range, even when the electrode height of the flexible substrate 21 (thickness of the second wiring 22) varies or when the flexible substrate 21 or the like is warped, the variation is absorbed and stabilized. Thus, the wirings can be connected.

  Subsequently, the pattern mask of the elastic deformable body 12 is aligned (S2). When the photosensitive material is used as the elastic deformable body 12, the photosensitive material can be patterned with ultraviolet rays (UV light). FIG. 2 shows a state in which the photomask 41 is aligned on the photosensitive material that is the elastic deformable body 12.

  Next, the pattern of the elastic deformation body 12 is formed (S3). That is, the photosensitive material is exposed to UV light and then developed to form a pattern of the convex elastic deformation body 12. At this time, the convex elastic deformable body 12 is formed so that the surface 12 a opposite to the rigid substrate 11 in the convex elastic deformable body 12 becomes a plane parallel to the rigid substrate 11.

(Wiring formation process)
In the wiring formation step, the first wiring 13 is formed on the surface 12a of the convex elastic deformation body 12 opposite to the rigid substrate 11. More specifically, it is as follows.

  First, as shown in FIG. 3, a photoresist 42 is applied onto the rigid substrate 11, exposed and developed, and a mask corresponding to the pattern of the first wiring 13 is formed (S4). And the metal layer which comprises the 1st wiring 13 is formed in the surface of the elastic deformation body 12 and the surface of the patterned photoresist 42 by a vacuum evaporation method or a sputtering method (S5). Here, the metal layer (first wiring 13) is formed in a three-layer structure of Al, Ni, and Au. As an example, the thickness of the Al layer is 1.5 μm, the Young's modulus is 70 GPa, the thickness of Ni is 0.5 μm, the Young's modulus is 200 GPa, the thickness of Au is 0.3 μm, and the Young's modulus Is 80 GPa.

  Thereafter, by performing lift-off, the metal layer is left only on the pattern of the elastic deformable body 12, and this is used as the first wiring 13 (S6). Since the first wiring 13 is located on the surface 12 a of the elastic deformable body 12, that is, on a plane parallel to the rigid substrate 11, the first wiring 13 is also formed in a planar shape parallel to the rigid substrate 11. .

(Crimping process)
In the crimping process, the first wiring 13 and the second wiring 22 are brought into direct contact with each other by crimping the flexible substrate 21 having the second wiring 22 formed on the surface thereof to the rigid substrate 11 via the adhesive 31. Let At this time, the convex elastic deformable body 12 is elastically deformed according to the expansion or contraction of the adhesive 31, so that the contact between the first wiring 13 and the second wiring 22 is maintained. By pressing the flexible substrate 21, the convex elastic deformation body 12 is held between the rigid substrate 11 and the flexible substrate 21 in a state of being elastically deformed in advance. More specifically, it is as follows.

  As shown in FIG. 4, an insulating resin (which is a nonconductive adhesive) is applied as an adhesive 31 on the rigid substrate 11 (S7). As the insulating resin, NCP or NCF can be used. When NCP is used, NCP is applied to a desired position using screen printing or the like. When NCF is used, NCF is attached so as to cover the first wiring 13 of the rigid substrate 11. Here, NCP (Panasonic CV5340E, Young's modulus: 3 GPa) is used as an example, but any other material (soft material) having a Young's modulus lower than that of the elastic deformable body 12 can be preferably used.

  Subsequently, the rigid substrate 11 is set on a stage of a bonding apparatus (not shown), and the rigid substrate 11 is placed so that the position of the first wiring 13 on the rigid substrate 11 and the position of the second wiring 22 on the flexible substrate 21 coincide. The substrate 11 and the flexible substrate 21 are aligned (S8). At this time, in order to improve the alignment accuracy, it is desirable to form alignment marks on the rigid substrate 11 and the flexible substrate 21 and match the positions of the wirings by matching the marks.

  For example, a polyimide resin is used as the flexible substrate 21. The thickness of the polyimide resin is, for example, 25 μm, and the Young's modulus is, for example, 5 GPa. The second wiring 22 has a three-layer structure of Al, Ni, and Au. As an example, the thickness of the Al layer is 7 μm, the Young's modulus is 70 GPa, the thickness of Ni is 1 μm, the Young's modulus is 200 GPa, the thickness of Au is 0.3 μm, and the Young's modulus is 80 GPa. .

  Next, as shown in FIG. 5, the flexible substrate 21 is pressure-bonded to the rigid substrate 11 by applying a predetermined load to the flexible substrate 21 by the crimping tool 43 of the joining device (S9). At this time, the crimping tool 43 is provided with a heating body, and performs heating to a predetermined temperature as well as pressurization. The adhesive 31 is thermally cured after being melted by pressing and heating. The pressurization is performed at 3 to 10 MPa, for example. About temperature, the temperature of the crimping | compression-bonding tool 43 is set so that the adhesive agent 31 (thermosetting resin) may be 170-250 degreeC. The crimping time is, for example, 15 seconds or less.

  The first wiring 13 of the rigid substrate 11 and the second wiring 22 of the flexible substrate 21 are in contact with each other by pressing, and between the adjacent first wirings 13 and 13 and the adjacent second wiring. In a state where the adhesive 31 is filled between 22 and 22, the adhesive 31 is cured (S10). Thereby, the connection structure 1 is obtained.

  By the pressurization, the elastic deformable body 12 on the rigid substrate 11 is held in a contracted state than before the pressurization. In addition, since the adhesive 31 is constantly stressed between the flexible substrate 21 and the rigid substrate 11 to contract the elastic deformable body 12, the first wiring 13 of the rigid substrate 11 has an elastic deformable body. The stress that pushes the second wiring 22 of the flexible substrate 21 is applied by the deformation recovery force (restoring force) 12. The thickness of the elastic deformable body 12 after the pressure bonding is, for example, 2 to 3 μm.

  FIG. 6 schematically shows a cross section of the connection structure 1 before and after the flexible substrate 21 is crimped to the rigid substrate 11. By the above crimping, the convex elastic deformable body 12 is not only contracted in the facing direction of the rigid substrate 11 and the flexible substrate 21 (the direction perpendicular to the rigid substrate 11), but the first wiring 13 is elastically deformed. By being buried in, it is elastically deformed so that the end is raised. However, in the surface 12a of the elastic deformation body 12, the part which contacts the 1st wiring 13 is still a plane.

  As described above, in the above-described crimping process, the convex elastic deformable body 12 and the rigid substrate 11 are flexible with the convex elastic deformable body 12 being elastically deformed in advance by the pressure bonding of the flexible substrate 21 to the rigid substrate 11. It is held between the substrate 21. Thereby, even if the adhesive 31 expands or contracts due to environmental changes, the contact between the first wiring 13 and the second wiring 22 can be maintained by the elastic deformation of the convex elastic deformation body 12. As a result, even if the adhesive 31 expands or contracts, conduction between the first wiring 13 and the second wiring 22 can be maintained.

  In the above description, the flexible substrate 21 is used as the second substrate facing the first substrate (the rigid substrate 11). The connection structure 1 manufactured in this way is suitable for an inkjet head described later. A rigid substrate may be used as the second substrate as long as the adhesive 31 can be heated to a temperature of 170 to 250 [deg.] C. to pressurize both substrates and pressure-bond them.

[Other configurations of connection structure]
FIG. 7 is a cross-sectional view showing another configuration of the connection structure 1 of the present embodiment. In the connection structure 1, the surface 12 a on the opposite side to the rigid substrate 11 in the convex elastic deformation body 12 may include a convex surface (convex surface) on the opposite side to the rigid substrate 11. The convex surface may be formed of any one of a spherical surface, an aspherical surface, a cylindrical surface, a composite surface including a plurality of planes, and a composite surface including a plane and a curved surface.

  The elastic deformable body 12 having the convex surface can be formed by using a nanoprinting method in the elastic deformable body forming step described above. At this time, it is desirable to use a UV curable resin as the material of the elastic deformation body. That is, after applying an elastic deformable material made of a photosensitive material on the rigid substrate 11, the elastic deformable material is pressed with a mold having a desired shape (concave shape) made of quartz or the like, and then irradiated with UV light. By curing the elastic deformable material, the elastic deformable body 12 whose surface 12a is a convex surface opposite to the rigid substrate 11 can be formed.

  When the surface 12a has a convex surface, the first wiring 13 positioned on the surface 12a of the elastic deformable body 12 is also formed in a convex shape along the surface 12a. In this case, when the flexible substrate 21 is crimped to the rigid substrate 11 via the adhesive 31, the adhesive 31 existing between the first wiring 13 and the second wiring 21 is removed from the first wiring 13. With the convex shape, it is possible to perform pressure bonding while efficiently extruding to the surroundings, thereby reducing the biting (remaining) of the adhesive 31 between the first wiring 13 and the second wiring 21 and thus biting. Can be eliminated. Therefore, it is possible to avoid a decrease in the contact area between the two wirings due to the adhesive 31 remaining between the first wiring 13 and the second wiring 21, and to avoid an increase in connection resistance between the two substrates. Can do. Therefore, for example, when the connection structure having the above configuration is applied to a device, it is possible to avoid a decrease in the performance of the device due to the increase in the connection resistance.

[Formation pattern of elastic deformation body]
8A is a plan view showing an example of a formation pattern of the elastic deformable body 12 on the rigid substrate 11, and FIG. 8B is a cross-sectional view taken along the line AA ′ in FIG. 8A. 9A is a plan view illustrating another example of the formation pattern of the elastic deformable body 12, and FIG. 9B is a cross-sectional view taken along the line BB ′ in FIG. 9A. 8A and 8B corresponds to the configuration on the rigid substrate 11 side before crimping, which is applied to the connection structure 1 in FIG. 9A and 9B corresponds to the configuration on the rigid substrate 11 side before crimping, which is applied to the connection structure 1 in FIG. For convenience of explanation below, the thickness direction of the rigid substrate 11 is defined as a Z direction, and two directions perpendicular to each other in a plane perpendicular to the Z direction are defined as an X direction and a Y direction, respectively.

  As shown in these drawings, the convex elastic deformation body 12 is positioned on the rigid substrate 11 such that the first wiring 13 extends in parallel with the direction (for example, the Y direction) extending along the rigid substrate 11. It may be. In this configuration, the first wiring 13 is formed only on the surface 12a of the convex elastic deformation body 12 (the entire first wiring 13 is formed on the surface 12a of the elastic deformation body 12). . Even if the elastic deformable body 12 and the first wiring 13 are in the positional relationship as described above, the convex elastic deformable body 12 is elastically deformed in accordance with the expansion or contraction of the adhesive 31, so that the first Since the contact between the wiring 13 and the second wiring 22 can be maintained, conduction between the two wirings can be maintained.

  10A is a plan view showing still another example of the formation pattern of the elastic deformable body 12, FIG. 10B is a cross-sectional view taken along the line CC ′ in FIG. 10A, and FIG. 10C is a rigid of FIG. 10A. 2 is a cross-sectional view of a connection structure in which a flexible substrate 21 is pressure-bonded to a substrate 11. FIG. As shown in FIG. 10B, the convex elastic deformable body 12 is formed on the rigid substrate 11 such that the first wiring 13 extends in a direction (X direction) intersecting the direction (Y direction) extending along the rigid substrate 11. May be located. In this configuration, a part of the first wiring 13 is formed on the surface 12 a of the convex elastic deformation body 12, and the rest is located on the rigid substrate 11. Further, as shown in FIG. 10A, the first wiring 13 is formed on the rigid substrate 11 so as to sequentially get over the elastic deformable body 12 extending in the X direction and spaced apart in the Y direction. Therefore, as shown in FIG. 10C, the first wiring 13 is in local contact with the planar second wiring 22. That is, the first wiring 13 is in contact with the second wiring 22 only at a portion that intersects the elastic deformable body 12.

  Thus, even when the elastic deformable body 12 and the first wiring 13 are formed on the rigid substrate 11, the first wiring is caused by the elastic deformation of the elastic deformable body 12 when the adhesive 31 expands or contracts. The contact between 13 and the second wiring 22 can be maintained although being local. Therefore, also in this case, the conduction between the first wiring 13 and the second wiring 22 can be maintained.

  11A is a plan view showing still another example of the formation pattern of the elastic deformable body 12, FIG. 11B is a cross-sectional view taken along line DD ′ in FIG. 11A, and FIG. 11C is a rigid view of FIG. 11A. 2 is a cross-sectional view of a connection structure in which a flexible substrate 21 is pressure-bonded to a substrate 11. 11A to 11C show the convex elastic deformation bodies 12 extending in the X direction in the configurations of FIGS. 10A to 10C so as to be separated between the adjacent first wirings 13 and 13 (separated in the X direction). As shown, a configuration positioned on the rigid substrate 11 is shown.

  In this configuration, as shown in FIG. 10B, the convex elastic deformable body 12 is connected to the adjacent first wirings 13 and 13 as compared with the case where the elastic deformable body 12 is formed (continuously in the X direction). Compared with the case where the elastic deformation body 12 is formed), a small amount (size) of the elastic deformation body 12 can maintain the continuity between both wirings, which is very advantageous in reducing the manufacturing cost.

[Configuration of inkjet head]
The connection structure 1 described above can be applied to an inkjet head and an inkjet printer. Hereinafter, an inkjet head and an inkjet printer will be described.

  12A is a plan view illustrating a schematic configuration of the inkjet head 100 to which the connection structure 1 is applied, FIG. 12B is a cross-sectional view taken along line EE ′ in FIG. 12A, and FIG. 12C is FIG. FIG. In FIG. 12A, the lower electrode 51 described later is not shown for convenience. FIG. 13 is a part of a cross-sectional view taken along the line G-G ′ in FIG. 12A.

  The inkjet head 100 is configured by bonding an inkjet substrate 10 and a wiring substrate 20 with an adhesive 31. The adhesive 31 is an adhesive member that bonds the inkjet substrate 10 and the wiring substrate 20, and is made of, for example, a non-conductive adhesive such as NCP or NCF.

(Inkjet substrate)
The inkjet substrate 10 is a substrate (also referred to as an inkjet head chip) that ejects ink based on a drive signal, and includes a rigid substrate 11 and a piezoelectric element 50.

《Rigid board》
The rigid substrate 11 is configured by bonding a body plate 11a (support substrate), an intermediate plate 12b, and a nozzle plate 11c (nozzle plate). The body plate 11a is composed of a semiconductor substrate or an SOI substrate made of single crystal Si alone. The body plate 11a is adjusted to a thickness of about 100 to 300 μm by polishing a substrate having a thickness of about 750 μm, for example. The thickness of the body plate 11a may be adjusted as appropriate according to the device to be applied.

  The body plate 11a is provided with a plurality of pressure chambers 11d for containing ink and ink supply ports 11e corresponding to the pressure chambers 11d. Ink supplied from an intermediate tank 105 (see FIG. 14) to be described later is supplied to the pressure chamber 11d through the ink supply port 11e. The ink supplied to the pressure chamber 11d may be a pigment ink or a dye ink. The upper wall (the wall located on the piezoelectric element 50 side) of the pressure chamber 11d in the body plate 11a constitutes a vibration plate 11f that is displaced (vibrated) with the driving (expansion / contraction) of the piezoelectric body 52 described later. A thermal oxide film such as silicon oxide may be provided on the diaphragm 11f for the purpose of protecting and insulating the body plate 11a.

  The intermediate plate 12b is made of a glass substrate having a thickness of about 100 to 300 μm, for example, and is a communication path 11g communicating with the pressure chamber 11d of the body plate 11a and a circulation channel for circulating non-ejection ink. And a common circulation channel 11h. The common circulation channel 11h communicates with the intermediate tank 105 through the ink discharge port 11k. The width of the common circulation channel 11h (the length in the left-right direction in FIG. 12B) is, for example, about 1.5 mm. The intermediate plate 12b is bonded to the body plate 11a by, for example, an adhesive, but may be bonded by anodic bonding.

  The nozzle plate 11c is made of, for example, a Si substrate having a thickness of about 100 to 300 μm, and includes a nozzle 11m and an individual flow path 11p. The nozzle 11m is a discharge hole (nozzle hole) that discharges the ink in the pressure chamber 11d to the outside, and communicates with the pressure chamber 11d through the communication path 11g. The individual flow path 11p is branched from the ink flow path from the pressure chamber 11d to the nozzle 11m via the communication path 11g, and is connected to the common circulation flow path 11h.

  The ink that has flowed into the common circulation flow path 11h via the individual flow path 11p is returned to the intermediate tank 105 by a pump or the like, and is supplied again to the pressure chamber 11d. As a result, it is possible to improve the ink ejection performance by removing bubbles and foreign matters in the pressure chamber 11d.

  Here, the ink supplied to the common circulation channel 11h includes ink drawn from the nozzle 11m when ink is not ejected, in addition to ink flowing from the pressure chamber 11d via the individual channel 11p. In any case, these inks are not ejected from the nozzle 11m. From this, it can be said that the common circulation channel 11h is a channel for circulating non-ejection ink other than the ink ejected from the nozzle 11m. Further, the common circulation channel 11h is a circulation channel (common channel) common to the individual pressure chambers 11d, which communicates with the individual pressure chambers 11d and circulates the non-ejection ink.

  The common circulation channel 11h only needs to be formed on at least one of the substrates constituting the rigid substrate 11, and is not limited to the configuration in which the common circulation channel 11h is formed in the intermediate plate 11b. In addition to the body plate 11a and the like described above, another substrate may be further provided to constitute the rigid substrate 11, and the common circulation channel 11h may be formed on the other substrate.

"Piezoelectric element"
The piezoelectric element 50 includes a lower electrode 51, a piezoelectric body 52, and an upper electrode 53. The piezoelectric element 50 may further include an orientation control layer (seed layer, buffer layer) for controlling the crystal orientation of the piezoelectric body 52 between the lower electrode 51 and the piezoelectric body 52.

  The lower electrode 51 is a common electrode provided in common for the plurality of pressure chambers 11 d and is formed over almost the entire surface of the rigid substrate 11. The lower electrode 51 is formed by laminating a Ti (titanium) layer and a Pt (platinum) layer. The Ti layer is formed to improve the adhesion between the Pt layer and the lower layer (thermal oxide film or diaphragm 11f). The thickness of the Ti layer is, for example, about 0.02 μm, and the thickness of the Pt layer is, for example, about 0.1 μm.

  The piezoelectric body 52 is made of a ferroelectric thin film (particularly, a film made of an oxide having a perovskite structure) such as lead zirconate titanate (PZT), and is supported by the rigid substrate 11 together with the lower electrode 51. Pressure is applied to the ink in the pressure chamber 11d. The piezoelectric body 52 is located above the pressure chamber 11d (on the wiring board 20 side), and is provided corresponding to each pressure chamber 11d. The piezoelectric body 52 is composed of, for example, a piezoelectric thin film having a thickness of 1 μm or more and 10 μm or less, but may be composed of a thickness (for example, bulk) larger than that. In addition, the piezoelectric body 52 may be configured by adding an additive such as lanthanum (La) or niobium (Nb) to PZT, and does not include lead, such as potassium sodium niobate (KNN). It may be constituted by.

  The upper electrode 53 is an individual electrode for driving the piezoelectric body 52, and is provided corresponding to each piezoelectric body 52 so as to sandwich the piezoelectric body 52 from the lower electrode 51 in the film thickness direction. . The upper electrode 53 is configured by laminating a Ti layer and a Pt layer. The Ti layer is formed in order to improve the adhesion between the piezoelectric body 52 and the Pt layer. The thickness of the Ti layer is about 0.02 μm, for example, and the thickness of the Pt layer is about 0.1 to 0.2 μm, for example. Note that a layer made of gold (Au) may be formed instead of the Pt layer.

  A part of the piezoelectric element 50 is covered with the elastic deformation body 12. A plurality of elastic deformation bodies 12 are provided in parallel on a part of the surface of the rigid substrate 11 via the lower electrode 51 (see FIG. 13). Each elastic deformable body 12 is formed in a convex shape protruding from the rigid board 11 toward the wiring board 20 and extends from above the pressure chamber 11d so as to straddle the common circulation channel 11h. A first wiring 13 for supplying a drive signal to the upper electrode 53 is provided on the surface 12a of the convex elastic deformable body 12. The upper electrode 53 corresponding to each piezoelectric body 52 is elastically deformed. The first wiring 13 on the body 12 is electrically connected.

  The inkjet substrate 10 and the wiring substrate 20 are pressure-bonded via an adhesive 31, whereby the convex elastic deformable body 12 is held in a state of being elastically deformed in advance.

(Wiring board)
The wiring substrate 20 is a substrate that supplies the drive signal to the inkjet substrate 10. For example, a plurality of second wirings 22 made of a conductive metal such as copper foil are provided on an insulating flexible substrate 21 made of polyimide or the like. It is formed by bonding and further covering a part of the second wiring 22 with an insulating film 23. Each second wiring 22 is electrically connected to a drive circuit (not shown) that generates the drive signal in order to supply the drive signal to the piezoelectric element 50.

  The plurality of second wirings 22 include a wiring 22a and a wiring 22b. The wiring 22 a is a wiring that is electrically connected to the first wiring 13 of the inkjet substrate 10 and supplies the drive signal to the upper electrode 53 of the piezoelectric element 50 via the first wiring 13. The wiring 22b is a wiring that is electrically connected to the lower electrode 51 of the inkjet substrate 10 and applies a potential (for example, a ground potential of 0 V) to the lower electrode 51.

  In the above configuration, a drive signal from a drive circuit (not shown) is supplied to the upper electrode 53 via the second wiring 22 (wiring 22a) and the first wiring 13 of the wiring board 20, and via the wiring 22b. To the lower electrode 51. As a result, a potential difference is generated between the lower electrode 51 and the upper electrode 53, and the piezoelectric body 52 expands and contracts in a direction perpendicular to the thickness direction according to the potential difference. Then, due to the difference in length between the piezoelectric body 52 and the diaphragm 11f, a curvature is generated in the diaphragm 11f, and the diaphragm 11f is displaced (curved or vibrated) in the thickness direction.

  Therefore, if ink is stored in the pressure chamber 11d, a pressure wave is propagated to the ink in the pressure chamber 11d by the vibration of the vibration plate 11f described above. As a result, the ink in the pressure chamber 11d is ejected to the outside as ink droplets via the communication path 11g and the nozzle 11m.

  In such an ink jet head 100, the convex elastic deformation body 12 is elastically deformed in advance and is held on the rigid substrate 11 in a state where the first wiring 13 and the second wiring 22 are in contact with each other. Therefore, even if the adhesive 31 expands or contracts due to a change in environmental conditions such as temperature or humidity, the convex elastic deformation body 12 is elastically deformed in a direction extending toward the flexible substrate 21 or contracting toward the rigid substrate 11. Thus, the contact between the first wiring 13 and the second wiring 22 can be maintained. Therefore, it is possible to maintain electrical connection between the first wiring 13 and the second wiring 22 regardless of changes in the use environment, and it is possible to realize a highly reliable ink jet head.

  In particular, in the inkjet head 200 in which the upper electrode 53 is connected to the first wiring 13, the piezoelectric material is applied by applying a driving voltage to the upper electrode 53 via the second wiring 22 and the first wiring 13. 52 is driven (stretched). Even if the adhesive 31 expands or contracts, the elastic deformation of the convex elastic deformable body 12 can maintain the contact between the first wiring 13 and the second wiring 22, regardless of changes in the usage environment. The piezoelectric body 52 can be appropriately driven according to the drive voltage. As a result, it is possible to avoid a decrease in ink ejection performance (for example, ejection failure) due to a change in use environment.

[Configuration of inkjet printer]
FIG. 14 is an explanatory diagram showing a schematic configuration of an inkjet printer 200 including the inkjet head 100 described above. The inkjet printer 200 forms an image on the recording medium P by ejecting ink from the inkjet head 100 toward the recording medium P. The ink jet printer 200 includes, for example, a so-called line head type ink jet recording apparatus in which the ink jet head 100 is provided in a line shape in the width direction of the recording medium.

  The ink jet printer 200 includes an ink jet head 100, a feed roll 101, a take-up roll 102, two back rolls 103 and 104, an intermediate tank 105, a liquid feed pump 106, a storage tank 107, and a fixing mechanism. 108.

  The ink jet head 100 ejects ink toward the recording medium P. In this embodiment, the ink jet head 100 is disposed at a position facing the recording medium P conveyed from one back roll 103 toward the fixing mechanism 108. Yes. A plurality of inkjet heads 100 may be provided corresponding to inks of different colors (for example, yellow, magenta, cyan, and black).

  The feed roll 101, the take-up roll 102, and each back roll 103 are cylindrical members that can rotate about their axes. The feeding roll 101 is a roll that feeds the long recording medium P wound around the circumferential surface toward the position facing the inkjet head 100. The feeding roll 101 is rotated by a driving unit (not shown) such as a motor to feed the recording medium P in the Q direction in FIG.

  The take-up roll 102 is taken out from the feed roll 101 and takes up the recording medium P on which the ink is ejected by the ink jet head 100 on the circumferential surface.

  The back rolls 103 and 104 are disposed between the feeding roll 101 and the take-up roll 102. One back roll 103 located on the upstream side in the conveyance direction of the recording medium P is placed at a position facing the inkjet head 100 while supporting the recording medium P fed by the feeding roll 101 around a part of the circumferential surface. Transport toward. The other back roll 104 conveys the recording medium P from a position facing the inkjet head 100 toward the take-up roll 102 while being wound around and supported by a part of the circumferential surface.

  The intermediate tank 105 temporarily stores the ink supplied from the storage tank 107. The intermediate tank 105 is connected to the ink tube 109, adjusts the back pressure of the ink in the ink jet head 100, and supplies ink to the ink jet head 100 through the ink tube 109.

  The liquid feed pump 106 supplies the ink stored in the storage tank 107 to the intermediate tank 105, and is arranged in the middle of the supply pipe 110. The ink stored in the storage tank 107 is pumped up by the liquid feed pump 106 and supplied to the intermediate tank 105 via the supply pipe 110.

  The fixing mechanism 108 fixes the ink ejected to the recording medium P by the inkjet head 100 on the recording medium P. The fixing mechanism 108 includes a heater for heating and fixing the ejected ink to the recording medium P, a UV lamp for curing the ink by irradiating the ejected ink with UV (ultraviolet light), and the like. Yes.

  In the above configuration, the recording medium P fed from the feeding roll 101 is conveyed to the position facing the inkjet head 100 by the back roll 103, and ink is ejected from the inkjet head 100 to the recording medium P. Thereafter, the ink ejected onto the recording medium P is fixed by the fixing mechanism 108, and the recording medium P after ink fixing is taken up by the take-up roll 102. As described above, in the line head type ink jet printer 200, ink is ejected while the recording medium P is conveyed while the ink jet head 100 is stationary, and an image is formed on the recording medium P.

  Note that the inkjet printer 200 may be configured to form an image on a recording medium by a serial head method. The serial head method is a method of forming an image by ejecting ink by moving an inkjet head in a direction orthogonal to the transport direction while transporting a recording medium. In this case, the ink jet head moves in the width direction of the recording medium while being supported by a structure such as a carriage. Further, as the recording medium, in addition to the long one, a sheet-like one cut in advance into a predetermined size (shape) may be used.

  The above-described ink jet printer 200 includes the highly reliable ink jet head 100 that can maintain electrical connection between the first wiring 13 and the second wiring 22 even when the adhesive 31 expands or contracts. Therefore, it is possible to realize a highly reliable ink jet printer with few failures such as defective printing.

  In the above description, the inkjet head and the inkjet printer that eject image forming ink have been described as examples. However, the ejected ink is not limited to the image forming ink. For example, a liquid such as a color material used for manufacturing a color filter such as a liquid crystal display or an electrode material used for forming an electrode such as an organic EL display or an FED (field emission display) may be used as the ink.

  The connection structure of the present invention can be used, for example, in an ink jet head or an ink jet printer.

1 Connection structure 11 Rigid substrate (first substrate)
11a Body plate (support substrate)
11c Nozzle plate (nozzle substrate)
11d Pressure chamber 11m Nozzle (nozzle hole)
12 elastic deformation body 12a surface 13 first wiring 21 flexible substrate (second substrate)
22 Second wiring 31 Adhesive (non-conductive adhesive)
51 Lower electrode 52 Piezoelectric body 53 Upper electrode 100 Inkjet head 200 Inkjet printer

Claims (19)

A first substrate and a second substrate located opposite to each other;
A connection structure including an adhesive for bonding the first substrate and the second substrate,
A convex elastic deformation body that is located directly or via a metal layer on a part of the surface of the first substrate and protrudes toward the second substrate;
A first wiring at least a part of which is located on the surface of the convex elastic deformation body opposite to the first substrate;
A second wiring positioned on the second substrate and in direct contact with the first wiring;
The convex elastic deformation body is elastically deformed in accordance with expansion or contraction of the adhesive, and is elastically deformed in advance so as to maintain contact between the first wiring and the second wiring. A connection structure which is held between the first substrate and the second substrate.   The convex elastic deformation body is expanded by a restoring force from a state of being elastically deformed in advance when the adhesive is expanded, and is contracted when the adhesive is contracted, whereby the first wiring and the second wiring are The connection structure according to claim 1, wherein the contact structure is maintained.   The connection structure according to claim 1, wherein a surface of the convex elastic deformable body opposite to the first substrate includes a plane parallel to the first substrate.   The surface on the opposite side to the first substrate in the convex elastic deformation body includes a convex surface on the opposite side to the first substrate. Connection structure.   The convex elastic deformation body is located on the first substrate such that the first wiring extends in parallel with a direction extending along the first substrate. The connection structure according to any one of 1 to 4.   The convex elastic deformation body is located on the first substrate such that the first wiring extends in a direction intersecting with a direction extending along the first substrate. The connection structure according to any one of claims 1 to 4.   The connection structure according to claim 6, wherein the convex elastic deformation body is positioned on the first substrate so as to be separated between the adjacent first wirings. The first substrate is a rigid substrate;
The connection structure according to claim 1, wherein the second substrate is a flexible substrate.   The connection structure according to claim 1, wherein the adhesive is a non-conductive adhesive.   The connection structure according to claim 9, wherein the nonconductive adhesive is a nonconductive film or a nonconductive paste. A connection structure according to any one of claims 1 to 10,
The first substrate of the connection structure is
A support substrate on which a pressure chamber for containing ink is formed;
An ink jet head comprising: a nozzle substrate having nozzle holes for discharging ink from the pressure chamber. Further including a lower electrode, a piezoelectric body, and an upper electrode in this order from the first substrate side;
The inkjet head according to claim 11, wherein the upper electrode is connected to the first wiring of the connection structure.   An ink jet printer comprising the ink jet head according to claim 11, wherein ink is ejected from the ink jet head toward a recording medium. An elastic deformable body forming step of forming a convex elastic deformable body projecting toward the second substrate directly or through a metal layer on a part of the surface of the first substrate;
A wiring forming step of forming a first wiring so that at least a part thereof is located on a surface of the convex elastic deformable body opposite to the first substrate;
A crimping process in which the first wiring and the second wiring are brought into direct contact with each other by crimping the second board on which the second wiring is formed to the first board via an adhesive. Including
In the crimping step, the convex elastic deformable body is elastically deformed according to the expansion or contraction of the adhesive, so that the contact between the first wiring and the second wiring is maintained by crimping. A method of manufacturing a connection structure, wherein the convex elastic deformation body is held between the first substrate and the second substrate in a state of being elastically deformed in advance.   In the elastic deformable body forming step, the convex elastic deformable body is formed such that a surface of the convex elastic deformable body opposite to the first substrate is a plane parallel to the first substrate. The method for manufacturing a connection structure according to claim 14, wherein:   In the elastic deformable body forming step, the convex surface is formed so that a surface of the convex elastic deformable body opposite to the first substrate becomes a convex surface opposite to the first substrate. The method for manufacturing a connection structure according to claim 14, wherein an elastic deformation body is formed. The first substrate is a rigid substrate;
The method for manufacturing a connection structure according to claim 14, wherein the second substrate is a flexible substrate.   The method for manufacturing a connection structure according to claim 14, wherein the adhesive is a non-conductive adhesive.   The method for manufacturing a connection structure according to claim 18, wherein the non-conductive adhesive is a non-conductive film or a non-conductive paste.

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