JP6772594B2 - Connection structure, manufacturing method of connection structure, inkjet head, and inkjet printer - Google Patents

Description

The present invention relates to a connection structure in which a first substrate and a second substrate are adhered with an adhesive, a method for manufacturing the same, 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 other wiring is formed, A technique using an anisotropic conductive adhesive is known. The anisotropic conductive adhesive is an adhesive in which conductive particles are dispersed in a resin, and is, for example, an anisotropic conductive film (ACF) or an anisotropic conductive paste (ACP). It has been known. As the above-mentioned conductive particles, for example, metal-coated resin balls, solder particles, and nickel (Ni) particles are used.

In bonding using an anisotropic conductive adhesive, conductive particles are sandwiched between the wiring (including electrodes and bumps) of the first substrate on which the functional element is formed and the wiring of the second substrate. Connect electrically. Therefore, the conductive particles need only be uniformly dispersed in the resin. The anisotropic conductive adhesive is melted by heating and pressurizing with a crimping tool, and the first substrate and the second substrate are bonded with the anisotropic conductive adhesive by thermosetting or ultraviolet curing the adhesive. Can be done.

In recent years, as the density of functional elements has increased, further fine pitching (narrowing of pitch, finer pitch) has been required for the wiring pitch formed on the substrate. In the above-mentioned bonding using an anisotropic conductive adhesive composed of ACF or ACP, it is required to finely pulverize the conductive particles to increase the filling rate. However, when the filling rate of the conductive particles is increased, There is a concern that the conductive particles may overlap each other and the conductive particles may aggregate between adjacent wires, causing an electrical short circuit.

Therefore, for example, in Patent Document 1, an anisotropic conductive sheet in which conductive particles and insulating particles having a specific gravity larger than that of the conductive particles are dispersed in a resin is arranged between two substrates, and is heated and pressurized to be described above. The resin is melted, the insulating particles are settled, 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) of the lower substrate. , The above two substrates are bonded together. Since the resin is cured in a state where the insulating particles are settled, aggregation of the conductive particles between adjacent wirings can be suppressed, which makes it possible to suppress an electrical short circuit.

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 adhesiveness. It is necessary to make it within the range of. By the way, when the content is smaller than the lower limit (2.5%), it becomes difficult to secure conductivity due to the decrease in particles (particularly conductive particles), and the content is the upper limit (12.5%). If it exceeds, the number of particles becomes too large, and it becomes difficult to secure the adhesiveness of the resin. Even in the adhesive of Patent Document 1 containing conductive particles and insulating particles, it is assumed that the same particle content as described above is set in order to ensure conductivity and adhesiveness. However, it is considered necessary to set the upper limit of the particle content so that the combined content of the conductive particles and the insulating particles does not exceed the upper limit (12.5%) from the viewpoint of ensuring adhesiveness. ..

In any case, when two substrates are bonded using an adhesive containing conductive particles, a current flows between the two substrates (between the upper and lower wirings) only in the portion where the conductive particles exist. Therefore, the connection resistance between the two substrates becomes high, and as a result, the following inconveniences may occur. That is, when a structure in which two substrates are bonded is applied to a device such as an inkjet head and a drive signal is supplied from one substrate to the other substrate, the drive signal is delayed or, for example, a square wave is a trapezoidal wave. The drive signal becomes blunt. As a result, the performance of the device (for example, print quality) deteriorates.

Therefore, for example, Patent Document 2 discloses a connection structure in which two substrates are connected via a resin layer that does not substantially 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 the adhesive, a connection structure can be obtained by pressing the two substrates through the resin layer so that the wirings of both substrates come into direct contact (contact) with each other.

As described above, by using the resin layer containing no conductive particles as the adhesive, there is no concern that an electrical short circuit occurs due to the conductive particles, which is advantageous in narrowing the wiring pitch. Further, since the wirings of both boards are in direct contact with each other, it is possible to significantly reduce the connection resistance between the two boards, and it is considered that the above-mentioned deterioration of the device performance can be avoided.

JP-A-2008-306024 (Claim 1, paragraphs [0013], [0033], [0048], FIGS. 1A, 1B, 7, etc.) Japanese Unexamined Patent Publication No. 2012-199262 (see claim 3, paragraphs [0016], [0038], [0042], FIG. 2, etc.)

By the way, adhesives generally expand or contract due to changes in environmental conditions such as temperature and humidity. Therefore, as in Patent Document 2, in a state where the wirings of both substrates are simply in contact with each other due to the adhesion of both substrates by an adhesive, the wirings become conductive when the state of the adhesive changes. The problem arises that it becomes impossible to maintain. That is, for example, when the adhesive expands in a high temperature environment or a high humidity environment, the expansion receives a force in the direction in which the substrates are separated from each other, so that the upper and lower wirings are separated from each other. Further, even if the adhesive subsequently 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, it becomes impossible to maintain the continuity between the wirings of the respective boards.

The present invention has been made to solve the above problems, and an object of the present invention is to expand or expand the adhesive in a configuration in which the substrates are bonded with an adhesive so that the wirings of the substrates are in direct contact with each other. Provided are a connection structure capable of maintaining continuity between wirings of each substrate even when contracted, a method for manufacturing the same, an inkjet head provided with the connection structure, and an inkjet printer provided with the inkjet head. There is.

The connection structure according to one aspect of the present invention is a connection structure including a first substrate and a second substrate located opposite to each other and an adhesive for adhering the first substrate and the second substrate. In the convex elastic deformed body, which is located on a part of the surface of the first substrate directly or via a metal layer and projects toward the second substrate side, and the convex elastic deformed body. The first wiring, which is at least partially located on the surface opposite to the first substrate, and the second wiring, which is located on the second substrate and is in direct contact with the first wiring, are provided. Further included, the convex elastic deformed body is elastically deformed in response to 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. In this state, it is held between the first substrate and the second substrate.

The method for manufacturing a connection structure according to another aspect of the present invention is a convex elastic deformed body that protrudes toward the second substrate side on a part of the surface of the first substrate, directly or via a metal layer. The elastic deformed body forming step of forming the above, and the wiring forming step of forming the first wiring so that at least a part of the convex elastic deformed body is located on the surface opposite to the first substrate. , The second substrate on which the second wiring is formed on the surface is crimped to the first substrate via an adhesive, so that the first wiring and the second wiring are in direct contact with each other. In the crimping step, the convex elastic deformable body elastically deforms in response to expansion or contraction of the adhesive to maintain contact between the first wiring and the second wiring. As described above, the convex elastic deformed body is held between the first substrate and the second substrate in a state of being elastically deformed in advance by crimping.

According to the above-mentioned connection structure and its manufacturing method, the first wiring of the first substrate and the second substrate are formed by adhering (crimping) the first substrate and the second substrate with an adhesive. Is in direct contact with the second wiring of. At this time, at least a part of the first wiring is located on the surface of the convex elastic deformed body. The convex elastic deformed body is elastically deformed in response to 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. It is held between the substrate and the second substrate. As a result, even if the adhesive expands or contracts, the conduction between the wirings of the respective substrates can be maintained by the elastic deformation of the elastically deformed body. In particular, since the elastically deformed body is held in the elastically deformed state in advance, the elastically deformed body can be expanded or contracted from the pre-elastically deformed state according to the expansion or contraction of the adhesive. It can be elastically deformed so that contact between the first and second wires can be maintained.

Further, since the elastic deformed body is convex and there is no member around the elastic deformed body that hinders the elastic deformation of the elastic deformed body, the elastic deformed body is freely elastically deformed in response to expansion or contraction of the adhesive. It becomes possible.

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

The convex elastic deformed body expands due to the restoring force from the elastically deformed state in advance when the adhesive expands, and contracts when the adhesive contracts, so that the first wiring and the second wiring Contact may be maintained. By utilizing the expansion and contraction of the elastically deformed body from the pre-elastically deformed state, the contact between the wirings between the first substrate and the second substrate and the contact between the first substrate and the second substrate both during expansion and contraction of the adhesive. Continuity can be reliably maintained.

The surface of the convex elastic deformed body opposite to the first substrate may include a plane parallel to the first substrate. Further, in the elastic deformed body forming step, the convex elastic body is formed so that the surface of the convex elastic deformed body opposite to the first substrate becomes a plane parallel to the first substrate. A variant may be formed. When the surface of the convex elastic deformed body includes a flat surface, the first wiring located on the flat surface is also flat. In a configuration having such a flat first wiring, the above-mentioned effect can be obtained.

The surface of the convex elastic deformed body opposite to the first substrate may include a convex surface on the opposite side to the first substrate. Further, in the elastic deformed body forming step, the surface of the convex elastic deformed body on the side opposite to the first substrate becomes a convex surface on the side opposite to the first substrate. The convex elastic deformed body may be formed.

If there is a convex surface on the surface of the convex elastic deformed body, the first wiring located on the convex surface is also convex. In this case, when the second substrate is crimped to the first substrate via the adhesive, it exists between the first wiring located on the elastically deformed body and the second wiring of the second substrate. The adhesive to be bonded can be crimped while being pushed out to the periphery 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 due to this. Therefore, for example, when the connection structure having the above configuration is applied to the device, it is possible to avoid the deterioration of the performance of the device due to the increase in the connection resistance.

The convex elastic deformed body may be located on the first substrate so that the first wiring extends in parallel with the direction extending along the first substrate. Further, the convex elastic deformed body may be located on the first substrate so that the first wiring extends in a direction intersecting the direction extending along the first substrate. In such a configuration in which the convex elastic deformed body is located on the first substrate, the above-mentioned effect can be obtained. In particular, the convex elastic deformed body may be located on the first substrate so as to be separated from the adjacent first wirings. In this case, the above-mentioned effect can be efficiently obtained with a small amount of the elastically deformed body as compared with the configuration in which the convex elastic deformed body is also formed 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-mentioned effect can be obtained in the configuration in which the rigid substrate is used as the first substrate and the flexible substrate is used as the second substrate.

In the above-mentioned connection structure and the method for producing the same, the adhesive may be a non-conductive adhesive. Further, the non-conductive adhesive may be a non-conductive film or a non-conductive paste. Since these non-conductive adhesives do not contain conductive particles for ensuring electrical conduction unlike conductive adhesives, there is no concern that electrical short circuits will occur due to conductive particles between adjacent wirings. Therefore, it is possible to form the first wiring and the second wiring at a narrow pitch (fine pitch).

The inkjet 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. Includes a nozzle substrate having a nozzle hole for ejecting ink from.

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 inkjet head having such a configuration, by using the connection structure described above, the continuity between the wirings between the first substrate and the second substrate is maintained even if the adhesive expands or contracts. Therefore, a highly reliable inkjet head can be realized.

The above-mentioned inkjet head further includes a lower electrode, a piezoelectric body, and an upper electrode in this order from the first substrate side, and even if the upper electrode is connected to the first wiring of the connection structure. Good. In this configuration, a driving voltage can be applied to the upper electrode via the second wiring and the first wiring to drive (expand / contract) the piezoelectric body. In such an inkjet head, even if the adhesive expands or contracts due to changes in the usage environment (temperature, humidity, etc.), the first substrate and the second substrate can be separated by using the above-mentioned connection structure. It is possible to maintain the continuity between the wirings between them. Therefore, the piezoelectric body can be appropriately driven according to the driving voltage regardless of the change in the usage environment.

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

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

It is sectional drawing which shows the schematic structure 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 after crimping of a flexible substrate to a rigid 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 the elastic deformed body. 8A is a cross-sectional view taken along the line AA'in FIG. 8A. It is a top view which shows another example of the formation pattern of an elastic deformed body. 9A is a cross-sectional view taken along the line BB'in FIG. 9A. It is a top view which shows still another example of the formation pattern of elastic deformed body. FIG. 10A is a cross-sectional view taken along the line CC'in FIG. 10A. It is sectional drawing of the connection structure which crimped the flexible substrate to the rigid substrate of FIG. 10A. It is a top view which shows still another example of the formation pattern of elastic deformed body. 11A is a cross-sectional view taken along the line DD'in FIG. 11A. It is sectional drawing of the connection structure which crimped the flexible substrate to the rigid substrate of FIG. 11A. It is a top view which shows the schematic structure of the inkjet head. 12A is a cross-sectional view taken along the line EE'in FIG. 12A. 12A is a cross-sectional view taken along the line FF'in FIG. 12A. It is a part of the cross-sectional view taken along the line GG'in FIG. 10A. It is explanatory drawing which shows the schematic structure of the inkjet printer.

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

[Structure of connection structure]
FIG. 1 is a cross-sectional view showing a schematic configuration of the 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 a single crystal Si (silicon), an SOI (Silicon on Insulator) substrate, a glass substrate, or a combination thereof. The above SOI substrate is formed by joining two Si substrates via an oxide film. The flexible substrate 21 is a flexible substrate and is arranged so as to face the rigid substrate 11. The flexible substrate 21 is made of a resin film such as polyimide. The adhesive 31 is an adhesive that adheres the rigid substrate 11 and the flexible substrate 21, and is a non-conductive adhesive (thermosetting insulation) such as a non-conductive film (NCF) or a non-conductive paste (NCP). It is composed of resin).

The connection structure 1 further includes an elastic deformed body 12, a first wiring 13, and a second wiring 22. A plurality of elastic deformed bodies 12 are provided on a part of the surface of the rigid substrate 11 so as to project from the rigid substrate 11 toward the flexible substrate 21 directly or via a metal layer, 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 deformed body 12 is located on the rigid substrate 11 so as to be separated from each other.

The metal layer may be provided as needed. For example, when the connection structure 1 of the present embodiment is applied to an inkjet head described later, the metal layer can be provided as a lower electrode of a piezoelectric element which is a functional element.

The elastically deformed body 12 is made of, for example, a photosensitive material made of polyimide resin or a parylene resin, but is made of any material as long as it is a material that elastically deforms in response to expansion or contraction of the adhesive 31. You may. The surface 12a of the elastically deformed body 12 opposite to the rigid substrate 11 includes, for example, a plane parallel to the rigid substrate 11.

A plurality of the first wirings 13 are provided, and at least a part thereof is located on the surface 12a of the convex elastic deformed body 12. Therefore, as shown in the figure, the entire first wiring 13 may be located on the surface 12a of the elastically deformed body 12, and as will be described later, only a part of the first wiring 13 is elastic. It may be located on the surface 12a of the deformed body 12 (the rest of the first wiring 13 may be located on the rigid substrate 11). When the surface 12a of the elastic deformed body 12 is flat, the first wiring 13 is formed flat 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), and gold (Au), and has a single-layer structure. It may be present or may have a laminated structure.

The second wiring 22 is located at a plurality of locations on the flexible substrate 21 in a pattern corresponding to each of the first wiring 13, and is in direct contact with the first wiring 13. Similar to the first wiring 13, the second wiring 22 may be made of a conductive metal material such as Al, Ti, Pt, Ni, or Au, and may have a single-layer structure. It may have a laminated structure.

The convex elastic deformed body 12 described above is elastically deformed in response to 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. As a result, even if the adhesive 31 expands or contracts due to environmental changes such as temperature changes and humidity changes, the continuity 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 sandwiching the adhesive 31 and the flexible substrate 21 move in a direction in which they are relatively separated from each other. At this time, the elastically deformed body 12 extends in a direction in which the first wiring 13 is displaced toward the flexible substrate 21 by the restoring force from the elastically deformed state in advance. Therefore, even if the rigid substrate 11 and the flexible substrate 21 are separated from each other, the contact between the first wiring 13 and the second wiring 22 can be maintained by the elongation of the elastic deformed body 12. On the other hand, when the adhesive 31 shrinks (when it tries to return to its original state) due to an environmental change from a high temperature to a low temperature, the rigid substrate 11 and the flexible substrate 21 move in a relatively close direction, and the first wiring 13 and the first wiring 13 The wiring 22 of 2 comes into contact (contact). At this time, stress (pressing pressure) from the second wiring 22 is applied to the first wiring 13, but the elastic deformed body 12 displaces the first wiring 13 toward the rigid substrate 11 due to the stress. Since it contracts 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 elastically deformed body 12 is held in a state of being elastically deformed in advance, the direction in which the elastically deformed body 12 is stretched from the elastically deformed body 12 in accordance with the expansion or contraction of the adhesive 31 In addition, it can be elastically deformed in the direction of contraction, whereby 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, the continuity between the first wiring 13 and the second wiring 22 can be maintained.

Further, since the elastic deformed body 12 is convex, there is no member that hinders the elastic deformation of the elastic deformed body 12 around the elastic deformed body 12 (between the adjacent elastic deformed bodies 12 and 12). Therefore, the convex elastic deformed body 12 is freely elastic in the direction in which the first wiring 13 is advanced and retracted (the direction perpendicular to the rigid substrate 11) as described above in response to the expansion or contraction of the adhesive 31. It can be transformed. An adhesive 31 exists around the convex elastic deformed body 12, and the adhesive 31 acts to stretch the elastic deformed body 12 when it expands, and elastic when it contracts. It acts to shrink the deformed body 12. That is, the adhesive 31 around the elastic deformed body 12 acts in a direction that promotes the elastic deformation of the elastic deformed body 12. Therefore, the adhesive 31 cannot be a member that inhibits the elastic deformation of the elastic deformed body 12.

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

Further, the convex elastic deformed body 12 expands due to the restoring force from the elastically deformed state in advance when the adhesive 31 expands, and contracts when the adhesive 31 contracts. In this way, by utilizing the expansion and contraction of the elastically deformed body 12 from the pre-elastically deformed state, the first wiring 13 and the second wiring 22 can be connected to each other during both expansion and contraction of the adhesive 31. Contact and continuity can be reliably maintained.

Further, even if there is a variation in height (thickness) between the first wiring 13 and the second wiring 22, the variation can be absorbed by the elastic deformation of the convex elastic deformed body 12. These electrical connections can be stabilized. Further, since the adhesive 31 is a non-conductive adhesive (thermosetting resin) and does not contain conductive particles, it is effective in preventing short-circuiting between adjacent first wirings 13 and 13. It is also possible to easily achieve fine pitch. Such fine pitching 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. It is very advantageous in that respect. Further, since the first wiring 13 and the second wiring 22 are in direct contact with each other without passing through conductive particles, the connection resistance between the rigid substrate 11 and the flexible substrate 21 can be significantly reduced, and the connection resistance can be reduced. It is also possible to avoid deterioration of device performance due to the increase.

[Manufacturing method of connection structure]
Next, the method for manufacturing the connection structure 1 described above will be described with reference to FIGS. 2 to 5. 2 to 5 are cross-sectional views showing a manufacturing process of the connection structure 1 of the present embodiment. The method for manufacturing the connection structure 1 of the present embodiment includes an elastic deformed body forming step, a wiring forming step, and a crimping step.

(Elastic deformed body forming process)
In the elastic deformed body forming step, a convex elastic deformed 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, a case where the elastic deformed body 12 is directly formed on a part of the surface of the rigid substrate 11 will be described, but the elastic deformed body 12 is formed via a metal layer (corresponding to the lower electrode described later). You may. In this case, for example, after forming a metal layer on the entire surface of the rigid substrate 11, an elastic deformed body 12 may be formed on a part of the surface of the metal layer.

First, as shown in FIG. 2, an elastic deformed body 12 is formed on the entire surface of the rigid substrate 11 (S1). As the rigid substrate 11, a Si substrate is used here. The Young's modulus of Si is about 65 GPa, and the total thickness of the Si substrate is about 500 μm. Further, as the elastic plasmodium 12, a photosensitive material made of a polyimide resin (for example, TMMR series manufactured by Tokyo Ohka 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 crimping is about 4 μm. The elastic deformed body 12 may be made of parylene resin. When the parylene resin is used, the elastic plasmodium 12 can be formed by vacuum vapor deposition.

The film thickness of the elastically deformed body 12 is preferably about 2 to 15 μm, for example. In such a thickness range, even if the electrode height of the flexible substrate 21 (thickness of the second wiring 22) varies or the flexible substrate 21 or the like is warped, the variation is absorbed and stable. It becomes possible to connect the wiring to each other.

Subsequently, the pattern mask of the elastic deformed body 12 is aligned (S2). When the photosensitive material is used as the elastic deformed body 12, it is possible to pattern the photosensitive material with ultraviolet rays (UV light). FIG. 2 shows a state in which the photomask 41 is aligned on the photosensitive material which is the elastic deformed body 12.

Next, the pattern of the elastic deformed 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 plasmodium 12. At this time, the convex elastic deformed body 12 is formed so that the surface 12a of the convex elastic deformed body 12 opposite to the rigid substrate 11 becomes a plane parallel to the rigid substrate 11.

(Wiring formation process)
In the wiring forming step, the first wiring 13 is formed on the surface 12a of the convex elastic deformed 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 and exposed and developed to form a mask corresponding to the pattern of the first wiring 13 (S4). Then, a metal layer constituting the first wiring 13 is formed on the surface of the elastic deformed body 12 and the surface of the patterned photoresist 42 by a vacuum vapor deposition method or a sputtering method (S5). Here, the metal layer (first wiring 13) is formed by 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.

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

(Crimping process)
In the crimping step, the flexible substrate 21 on which the second wiring 22 is formed on the surface is crimped to the rigid substrate 11 via the adhesive 31 so that the first wiring 13 and the second wiring 22 are in direct contact with each other. Let me. At this time, the convex elastic deformed body 12 elastically deforms in response to the expansion or contraction of the adhesive 31 with respect to the rigid substrate 11 so as to maintain contact between the first wiring 13 and the second wiring 22. By crimping the flexible substrate 21, the convex elastic deformed 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 non-conductive 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 by screen printing or the like. When NCF is used, the NCF is attached so as to cover the first wiring 13 of the rigid substrate 11. Here, NCP (CV5340E manufactured by Panasonic Corporation, 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 plasmodium 12 can be preferably used.

Subsequently, the rigid substrate 11 is set on the stage of the joining device (not shown), and the rigid substrate 11 is rigid so that the position of the first wiring 13 of the rigid substrate 11 and the position of the second wiring 22 of the flexible substrate 21 match. The substrate 11 and the flexible substrate 21 are aligned (S8). At this time, in order to improve the accuracy of alignment, it is desirable to form alignment marks on the rigid substrate 11 and the flexible substrate 21 and align the marks with each other to match the positions of the wirings.

As the flexible substrate 21, for example, a polyimide resin was used. The thickness of the polyimide resin is, for example, 25 μm, and the Young's modulus is, for example, 5 GPa. Further, as the second wiring 22, a wiring having a three-layer structure of Al, Ni, and Au was used. 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, a predetermined load is applied to the flexible substrate 21 by the crimping tool 43 of the joining device to crimp the flexible substrate 21 to the rigid substrate 11 (S9). At this time, the crimping tool 43 is provided with a heating body, and heats up to a predetermined temperature as well as pressurizing. The adhesive 31 is melted by pressurization and heating, and then thermosetting. The pressurization is performed at, for example, 3 to 10 MPa. Regarding the temperature, the temperature of the crimping tool 43 is set so that the adhesive 31 (thermosetting resin) has a temperature of 170 to 250 ° C. The crimping time is, for example, 15 seconds or less.

Due to pressurization, 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, and between the adjacent first wirings 13 and 13 and the adjacent second wiring. The adhesive 31 is cured with the adhesive 31 filled between 22 and 22 (S10). As a result, the connection structure 1 is obtained.

Due to the above pressurization, the elastic plasmodium 12 on the rigid substrate 11 is held in a contracted state as compared with that before the pressurization. Further, since the stress that contracts the elastic deformed body 12 is always applied between the flexible substrate 21 and the rigid substrate 11 due to the adhesive 31, the elastic deformed body 13 is connected to the first wiring 13 of the rigid substrate 11. Due to the deformation recovery force (restoring force) of the twelve, a stress that pushes the second wiring 22 of the flexible substrate 21 is applied. The thickness of the elastically deformed body 12 after crimping is, for example, 2 to 3 μm.

FIG. 6 schematically shows a cross section of the connection structure 1 before and after crimping the flexible substrate 21 onto the rigid substrate 11. By the above crimping, the convex elastic deformed body 12 not only shrinks in the direction opposite to the rigid substrate 11 and the flexible substrate 21 (the direction perpendicular to the rigid substrate 11), but also the first wiring 13 is elastically deformed. By being buried in, it is elastically deformed so that the end part rises. However, on the surface 12a of the elastic deformed body 12, the portion in contact with the first wiring 13 is still flat.

As described above, in the above-mentioned crimping step, the convex elastic deformed body 12 is elastically deformed in advance by crimping the flexible substrate 21 against the rigid substrate 11, and the convex elastic deformed body 12 is flexible with the rigid substrate 11. It is held between the substrate 21 and the substrate 21. As a result, even if the adhesive 31 expands or contracts due to changes in the environment, the contact between the first wiring 13 and the second wiring 22 can be maintained by the elastic deformation of the convex elastic deformed body 12. As a result, even if the adhesive 31 expands or contracts, the continuity between the first wiring 13 and the second wiring 22 can be maintained.

In the above, the flexible substrate 21 is used as the second substrate facing the first substrate (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 ° C. to pressurize and crimp both substrates.

[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 12a of the convex elastic deformed body 12 on the side opposite to the rigid substrate 11 may include a convex surface (convex surface) on the side opposite to the rigid substrate 11. The convex surface may be composed of a spherical surface, an aspherical surface, a cylindrical surface, a composite surface composed of a plurality of planes, or a composite surface composed of a plane and a curved surface.

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

When a convex surface is present on the surface 12a, the first wiring 13 located on the surface 12a of the elastic deformed body 12 is also formed to be convex 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 applied to the first wiring 13. The convex shape allows crimping while efficiently extruding to the periphery, thereby reducing the biting (residual) 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 the connection resistance between the two substrates. Can be done. Therefore, for example, when the connection structure having the above configuration is applied to the device, it is possible to avoid the deterioration of the performance of the device due to the increase in the connection resistance.

[Regarding the formation pattern of elastic plasmodium]
FIG. 8A is a plan view showing an example of the formation pattern of the elastic deformed 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 showing another example of the formation pattern of the elastically deformed body 12, and FIG. 9B is a cross-sectional view taken along the line BB'in FIG. 9A. The formation patterns of FIGS. 8A and 8B correspond to the configuration on the rigid substrate 11 side before crimping, which is applied to the connection structure 1 of FIG. Further, the formation patterns of FIGS. 9A and 9B correspond to the configuration on the rigid substrate 11 side before crimping, which is applied to the connection structure 1 of FIG. 7. For convenience of explanation below, the thickness direction of the rigid substrate 11 is the Z direction, and the two directions perpendicular to each other in the plane perpendicular to the Z direction are the X direction and the Y direction, respectively.

As shown in these drawings, the convex elastic deformed body 12 is located on the rigid substrate 11 so that the first wiring 13 extends parallel to the direction (for example, the Y direction) extending along the rigid substrate 11. You may be. In this configuration, the first wiring 13 is formed only on the surface 12a of the convex elastic deformed body 12 (the entire first wiring 13 is formed on the surface 12a of the elastic deformed body 12). .. Even if the elastic deformed body 12 and the first wiring 13 have the above positional relationship, the convex elastic deformed body 12 elastically deforms in response to the expansion or contraction of the adhesive 31, so that the first elastic deformed body 12 is elastically deformed. Since the contact between the wiring 13 and the second wiring 22 can be maintained, the continuity between the two wirings can be maintained.

10A is a plan view showing still another example of the formation pattern of the elastic deformed 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. It is sectional drawing of the connection structure which crimped the flexible substrate 21 to the substrate 11. As shown in FIG. 10B, the convex elastic deformed body 12 is placed on the rigid substrate 11 so that the first wiring 13 extends in the direction (X direction) intersecting with the extending direction (Y direction) along the rigid substrate 11. It may be located in. In this configuration, a part of the first wiring 13 is formed on the surface 12a of the convex elastic deformed 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 overcome the elastic deformed body 12 extending in the X direction and separated from the Y direction in the Y direction. Therefore, as shown in FIG. 10C, the first wiring 13 comes into local contact with the flat second wiring 22. That is, the first wiring 13 comes into contact with the second wiring 22 only at the portion intersecting the elastic deformed body 12.

In this way, even when the elastic deformed 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 deformed body 12 when the adhesive 31 expands or contracts. The contact between the 13 and the second wiring 22 can still be maintained, albeit locally. Therefore, in this case as well, the continuity 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 deformed body 12, FIG. 11B is a cross-sectional view taken along the line DD'in FIG. 11A, and FIG. 11C is a rigid of FIG. 11A. It is sectional drawing of the connection structure which crimped the flexible substrate 21 to the substrate 11. 11A to 11C show that in the configuration of FIGS. 10A to 10C, the convex elastic plasmodium 12 extending in the X direction is separated from the adjacent first wirings 13 and 13 (separated in the X direction). As shown), the configuration is shown on the rigid substrate 11.

In this configuration, as compared with the case where the convex elastic deformed body 12 is formed between the adjacent first wirings 13 and 13 as shown in FIG. 10B, the elastic deformed body 12 is continuously formed in the X direction. With a smaller amount (size) of the elastic deformed body 12 (compared to the case of forming the elastic deformed body 12), the continuity of both wirings can be maintained, 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 showing a schematic configuration of an inkjet head 100 to which the connection structure 1 is applied, FIG. 12B is a cross-sectional view taken along the line EE'in FIG. 12A, and FIG. 12C is FIG. 12A. It is a cross-sectional view taken along the line FF'in the above. In FIG. 12A, the lower electrode 51, which will be described later, is not shown for convenience. Further, FIG. 13 is a part of a cross-sectional view taken along the line GG'in FIG. 12A.

The inkjet head 100 is configured by adhering an inkjet substrate 10 and a wiring substrate 20 with an adhesive 31. The adhesive 31 is an adhesive member that adheres the inkjet substrate 10 and the wiring board 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 has a rigid substrate 11 and a piezoelectric element 50.

《Rigid board》
The rigid substrate 11 is configured by laminating 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 a single crystal Si alone. The body plate 11a is adjusted to a thickness of about 100 to 300 μm by, for example, polishing a substrate having a thickness of about 750 μm. The thickness of the body plate 11a may be appropriately adjusted according to the device to be applied.

The body plate 11a is provided with a plurality of pressure chambers 11d for accommodating ink and ink supply ports 11e corresponding to each pressure chamber 11d. The ink supplied from the intermediate tank 105 (see FIG. 14), which will be described later, is supplied to the pressure chamber 11d via 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 (wall located on the piezoelectric element 50 side) of the pressure chamber 11d in the body plate 11a constitutes a diaphragm 11f that is displaced (vibrated) with the drive (expansion and 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 composed of, for example, a glass substrate having a thickness of about 100 to 300 μm, and is a communication passage 11g communicating with the pressure chamber 11d of the body plate 11a and a circulation passage for circulating non-ejection ink. It has a common circulation flow path 11h. The common circulation flow path 11h communicates with the intermediate tank 105 via the ink discharge port 11k. The width of the common circulation flow path 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 has a nozzle 11 m and an individual flow path 11p. The nozzle 11m is a discharge hole (nozzle hole) for ejecting ink in the pressure chamber 11d to the outside, and communicates with the pressure chamber 11d via a communication passage 11g. The individual flow path 11p is provided by branching from the ink flow path from the pressure chamber 11d to the nozzle 11m via the communication passage 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 to the pressure chamber 11d again. This makes it possible to remove air bubbles and foreign substances in the pressure chamber 11d to improve the ink ejection performance.

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

The common circulation flow path 11h may 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 flow path 11h is formed on the intermediate plate 11b. Further, in addition to the body plate 11a and the like described above, another substrate may be further provided to form the rigid substrate 11, and the common circulation flow path 11h may be formed on the other substrate.

"Piezoelectric element"
The piezoelectric element 50 has a lower electrode 51, a piezoelectric body 52, and an upper electrode 53. The piezoelectric element 50 may further have 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 commonly provided in the plurality of pressure chambers 11d, 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 composed of a ferroelectric thin film (particularly a film made of an oxide having a perovskite-type 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 made of, for example, a piezoelectric thin film having a thickness of 1 μm or more and 10 μm or less, but may be made of a piezoelectric thin film having a thickness of 1 μm or more and 10 μm or less (for example, bulk). Further, the piezoelectric body 52 may be composed of PZT to which an additive such as lanthanum (La) or niobium (Nb) is added, and is a lead-free piezoelectric material such as sodium potassium niobate (KNN). It may be composed of.

The upper electrode 53 is an individual electrode for driving the piezoelectric body 52, and is provided corresponding to the individual piezoelectric body 52 so as to sandwich the piezoelectric body 52 with the lower electrode 51 from the film thickness direction. .. The upper electrode 53 is formed by laminating a Ti layer and a Pt layer. The Ti layer is formed to improve the adhesion between the piezoelectric body 52 and the Pt layer. 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 to 0.2 μm. 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 deformed body 12. A plurality of elastic deformed 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). Further, each elastic deformed body 12 is formed in a convex shape protruding from the rigid substrate 11 toward the wiring substrate 20, and extends from above the pressure chamber 11d so as to straddle the common circulation flow path 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 deformed body 12, and the upper electrode 53 corresponding to each piezoelectric body 52 is elastically deformed. It is electrically connected to the first wiring 13 on the body 12.

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

(Wiring board)
The wiring board 20 is a board that supplies the drive signal to the inkjet board 10. For example, a plurality of second wiring boards 22 made of a conductive metal such as copper foil are placed on an insulating flexible board 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 of the second wirings 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 the wiring 22a and the wiring 22b. The wiring 22a 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 to give a potential (for example, a ground potential of 0V) 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 also via the wiring 22b. Is supplied 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 above potential difference. Then, due to the difference in length between the piezoelectric body 52 and the diaphragm 11f, the diaphragm 11f is curved, and the diaphragm 11f is displaced (curved, vibrated) in the thickness direction.

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

In such an inkjet head 100, the convex elastic deformed body 12 is elastically deformed in advance and 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 changes in environmental conditions such as temperature or humidity, the convex elastic deformable body 12 elastically deforms in the direction of extending toward the flexible substrate 21 or contracting toward the rigid substrate 11. Then, it becomes possible to maintain the contact between the first wiring 13 and the second wiring 22. Therefore, it is possible to maintain the continuity between the first wiring 13 and the second wiring 22 regardless of the change in the usage environment, and it is possible to realize a highly reliable inkjet 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 formed by applying a driving voltage to the upper electrode 53 via the second wiring 22 and the first wiring 13. Drives (expands and contracts) 52. Even if the adhesive 31 expands or contracts, the elastic deformation of the convex elastic deformed body 12 can maintain the contact between the first wiring 13 and the second wiring 22, so that the contact between the first wiring 13 and the second wiring 22 can be maintained regardless of changes in the usage environment. The piezoelectric body 52 can be appropriately driven according to the driving voltage. As a result, it is possible to avoid deterioration of ink ejection performance (for example, ejection failure) due to changes in the usage environment.

[Configuration of Inkjet Printer]
FIG. 14 is an explanatory diagram showing a schematic configuration of an inkjet printer 200 provided with the above-mentioned inkjet head 100. 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 inkjet printer 200 is composed of, for example, a so-called line head type inkjet recording device in which an inkjet head 100 is provided in a line shape in the width direction of a recording medium.

The inkjet printer 200 includes the above-mentioned inkjet head 100, a feeding roll 101, a take-up roll 102, two back rolls 103 and 104, an intermediate tank 105, a liquid feeding pump 106, a storage tank 107, and a fixing mechanism. It is equipped with 108.

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

The feeding roll 101, the winding roll 102, and each back roll 103 are members having a cylindrical shape that can rotate around an axis. The feeding roll 101 is a roll in which a long recording medium P wound around the peripheral surface in a number of layers is fed toward a position facing the inkjet head 100. The feeding roll 101 is rotated by a driving means (not shown) such as a motor, so that the recording medium P is fed and conveyed in the Q direction of FIG.

The take-up roll 102 is unwound from the pay-out roll 101, and winds up the recording medium P on which the ink is ejected by the inkjet head 100 on the peripheral surface.

The back rolls 103 and 104 are arranged between the feeding roll 101 and the winding roll 102. One back roll 103 located on the upstream side in the transport direction of the recording medium P is positioned at a position facing the inkjet head 100 while supporting the recording medium P unwound by the feeding roll 101 by winding it around a part of the peripheral surface. Transport toward. The other back roll 104 carries the recording medium P around a part of the peripheral surface while supporting it from a position facing the inkjet head 100 toward the take-up roll 102.

The intermediate tank 105 temporarily stores the ink supplied from the storage tank 107. Further, the intermediate tank 105 is connected to the ink tube 109, adjusts the back pressure of the ink in the inkjet head 100, and supplies the ink to the inkjet head 100 via 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 to the recording medium P. The fixing mechanism 108 is composed of a heater for heating and fixing the ejected ink to the recording medium P, a UV lamp for curing the ejected ink by irradiating the ejected ink with UV (ultraviolet rays), and the like. There is.

In the above configuration, the recording medium P unwound from the feeding roll 101 is conveyed to a 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. After that, the ink ejected to the recording medium P is fixed by the fixing mechanism 108, and the recording medium P after the ink is fixed is wound up by the take-up roll 102. In this way, in the line head type inkjet printer 200, with the inkjet head 100 stationary, ink is ejected while conveying the recording medium P, and an image is formed on the recording medium P.

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 in which an image is formed by ejecting ink by moving an inkjet head in a direction orthogonal to the conveying direction while conveying a recording medium. In this case, the inkjet 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, a sheet-like medium pre-cut to a predetermined size (shape) may be used in addition to the long-shaped one.

The above-mentioned inkjet printer 200 provides a highly reliable inkjet head 100 capable of maintaining continuity between the first wiring 13 and the second wiring 22 even when the adhesive 31 expands or contracts. Since it is provided, it is possible to realize a highly reliable inkjet printer with few failures such as printing defects.

In the above description, the inkjet head and the inkjet printer that eject the ink for image formation have been described as an example, but the ink to be ejected is not limited to the ink for image formation. 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 a FED (field emission display) may be used as an ink.

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

1 Connection structure 11 Rigid board (first board)
11a Body plate (support substrate)
11c Nozzle plate (nozzle substrate)
11d pressure chamber 11m nozzle (nozzle hole)
12 Elastic deformed 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)

The first substrate and the second substrate located opposite to each other,
A connection structure containing the first substrate and an adhesive for adhering the second substrate.
A convex elastic plasmodium located directly on a part of the surface of the first substrate or via a metal layer and projecting toward the second substrate.
The first wiring, which is at least partially located on the surface of the convex elastic plasmodium opposite to the first substrate,
Further including a second wire located on the second substrate and in direct contact with the first wire.
The convex elastic deformed body is elastically deformed in response to 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. It is held between the first substrate and the second substrate, and is held between the first substrate and the second substrate .
A connecting structure characterized in that the Young's modulus of the adhesive is lower than the Young's modulus of the convex elastically deformed body. The convex elastic deformed body expands due to the restoring force from the elastically deformed state in advance when the adhesive expands, and contracts when the adhesive contracts, so that the first wiring and the second wiring The connection structure according to claim 1, wherein the contact is maintained. The connection structure according to claim 1 or 2, wherein the surface of the convex elastic plasmodium opposite to the first substrate includes a plane parallel to the first substrate. The first or second aspect of the convex elastic plasmodium, wherein the surface of the convex elastic deformed body opposite to the first substrate includes a convex surface on the opposite side of the first substrate. Connection structure. The convex elastic deformed body is characterized in that it is located on the first substrate so that the first wiring extends in parallel with the direction extending along the first substrate. The connection structure according to any one of 1 to 4. The convex elastic deformed body is characterized in that it is located on the first substrate so that the first wiring extends in a direction intersecting 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 deformed body is located on the first substrate so as to be separated from the adjacent first wirings. The first substrate is a rigid substrate, and the first substrate is a rigid substrate.
The connection structure according to any one of claims 1 to 7, wherein the second substrate is a flexible substrate. The connection structure according to any one of claims 1 to 8, wherein the adhesive is a non-conductive adhesive. The connection structure according to claim 9, wherein the non-conductive adhesive is a non-conductive film or a non-conductive paste. The connection structure according to any one of claims 1 to 10 is included.
The first substrate of the connection structure is
A support substrate on which a pressure chamber for accommodating ink is formed,
An inkjet head including a nozzle substrate having a nozzle hole for ejecting ink from the pressure chamber. The lower electrode, the piezoelectric body, and the upper electrode are further included 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 inkjet printer comprising the inkjet head according to claim 11 or 12, wherein ink is ejected from the inkjet head toward a recording medium. An elastic plasmodium forming step of forming a convex elastic plasmodium protruding toward the second substrate side directly or via 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 of the convex elastic deformed body is located on a surface opposite to the first substrate.
It said second substrate second wiring is formed on the surface, by crimping the first substrate via the low adhesive Young's modulus than the convex elastic deformable body, the first Including a crimping step of directly contacting the wiring with the second wiring.
In the crimping step, the convex elastic deformed body is elastically deformed in response to expansion or contraction of the adhesive to maintain contact between the first wiring and the second wiring by crimping. A method for producing a connection structure, which comprises holding the convex elastic deformed body in a state of being elastically deformed in advance between the first substrate and the second substrate. In the elastic deformed body forming step, the convex elastic deformed body is formed so that the surface of the convex elastic deformed body opposite to the first substrate becomes a plane parallel to the first substrate. The method for manufacturing a connection structure according to claim 14, wherein the connection structure is formed. In the elastic deformed body forming step, the convex surface of the convex elastic deformed body opposite to the first substrate becomes a convex surface opposite to the first substrate. The method for manufacturing a connecting structure according to claim 14, wherein the elastically deformed body is formed. The first substrate is a rigid substrate, and the first substrate is a rigid substrate.
The method for manufacturing a connection structure according to any one of claims 14 to 16, wherein the second substrate is a flexible substrate. The method for manufacturing a connecting structure according to any one of claims 14 to 17, 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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