JP2011146502A - Circuit board and connection structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a circuit board that secures an excellent conductive connection state by eliminating a poor connection between terminals during connection, and makes pitches of the terminals fine and saves the space of a printed board, and to provide a connection structure. <P>SOLUTION: The circuit board includes a base substrate 30 and a plurality of first terminals 40 disposed on the base substrate 30 while extending parallel with one another, and grooves 41 which obliquely intersect extension directions of the respective first terminals 40 are formed on upper surfaces of the plurality of first terminals 40. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a circuit board and a connection structure.

  2. Description of the Related Art Conventionally, in circuit boards and liquid crystal display devices mounted on various electronic devices, a printed board such as a flexible board (hereinafter referred to as an FPC) or a rigid board on which a plurality of first terminals are arranged is used as a plurality of second terminals. A technique for connecting to a connection board having the following is used. For example, an FPC on which an IC chip for driving a liquid crystal panel is mounted is connected to the liquid crystal display device in a state where a plurality of first terminals and second terminals are aligned. The FPC on which the IC chip is mounted may be directly connected to a rigid substrate such as a glass substrate constituting the liquid crystal panel, or may be connected to an FPC mounted on the liquid crystal panel.

  Such connection between the printed board and the connection board is performed by interposing an anisotropic conductive film (hereinafter referred to as ACF) or an anisotropic conductive paste (hereinafter referred to as ACP) between them. Alternatively, the printed circuit board and the connection board are brought into pressure contact with each other, the first terminal and the second terminal are brought into direct contact, and an adhesive is filled between the printed circuit board and the connection board to be fixed.

However, since connection by ACF or ACP is obtained by conductive particles in the resin, if the first terminal arranged on the printed circuit board becomes thin, the connection area becomes small, so a sufficient amount of conductive particles. Is not secured, and there is a problem that stable conduction cannot be obtained or resistance increases.
On the other hand, it is conceivable to increase the connection area by increasing the thickness of the first terminals in order to secure conductive particles. However, the fine pitch of the first terminals arranged on the printed board and the space saving of the printed board are achieved. It becomes difficult.
Further, when connecting a printed circuit board in which a plurality of first terminals are arranged at a fine pitch, there is a possibility that a short circuit may occur due to dispersion of conductive particles between two adjacent first terminals.

  As a technique for solving such a problem, for example, in Patent Documents 1 and 2, a pair of conductors are made of metal in an overlapping region of a planar multiconductor formed by arranging a plurality of conductors in a substantially flat member. It is joined with a bond and its periphery is joined with a thermosetting adhesive. Thereby, the planar multiconductor in which a plurality of conductors are finely pitched can be reliably connected.

Japanese Patent No. 4152196 JP 2006-24751 A

In the techniques of Patent Documents 1 and 2, since the unevenness is formed on the upper surface of the planar multiconductor conductor, the unevenness of the conductor can penetrate through the adhesive layer, and the conductors are directly connected to each other. Although it is thought that it can contact, there are also the following problems.
In the techniques of Patent Documents 1 and 2, the concave and convex concave portions formed on the upper surface of the conductor are orthogonal to the discharge direction of the adhesive used when connecting the planar multiconductor. For this reason, when connecting a planar multiconductor, discharge | emission of an adhesive agent may be inhibited by the said recessed part formed in the upper surface of a conductor. Thereby, an adhesive agent intervenes between a pair of conductors, and there is a possibility that poor connection occurs.

  The present invention has been made in view of such circumstances and eliminates a connection failure between terminals at the time of connection to ensure a good conductive connection state, and further reduces the pitch of the terminals and saves space on the printed circuit board. An object of the present invention is to provide a circuit board and a connection structure that can be made simple.

  In order to solve the above problems, a circuit board according to the present invention includes a base substrate and a plurality of first terminals arranged in parallel with each other on the base substrate, and the plurality of first terminals. A groove that obliquely intersects with the extending direction of each of the first terminals is formed on the upper surface of the terminal.

  According to this configuration, when the circuit board and the connection board are connected via the uncured or semi-cured adhesive member (flexible adhesive member), the flexible adhesive member is smoothly discharged to the outside. . Specifically, a case where a flexible adhesive member is disposed in a recess (main flow path) between two adjacent first terminals when the circuit board and the connection board are connected is considered. Here, the “main flow path” is a path through which most of the flexible adhesive member flows during bonding. In addition, the plurality of grooves formed obliquely intersecting the extending direction of each first terminal on the top surfaces of the plurality of first terminals communicate with the main flow path, and are flexible adhesive members at the time of bonding. This is a branch channel. Here, the “branch channel” is an auxiliary channel that allows a flexible adhesive member overflowing from the main channel during bonding to flow to the adjacent main channel across the first terminal. Then, most of the flexible adhesive members flow along the extending direction of the main flow path that is initially arranged, and are discharged to the outside. At this time, a part of the flexible adhesive member enters the branch channel branched from the main channel. Then, the flexible adhesive member that has entered the branch channel flows into the adjacent main channel across the first terminal. Next, the flexible adhesive member arranged in the adjacent main channel flows along the extending direction of the adjacent main channel and is discharged to the outside. Hereinafter, the flexible adhesive member is discharged outside while repeating the above-described flow. As described above, since the branch channel is formed obliquely intersecting with the extending direction of the main channel, the flow of the flexible adhesive member is formed on the upper surface of the conductor shown in Patent Documents 1 and 2. Compared to a structure in which the concave and convex portions are orthogonal to the discharge direction of the adhesive used when connecting the planar multiconductor, the discharge of the flexible adhesive member is smoothly prevented from being disturbed by the concave portion. Can be discharged. Therefore, it is possible to provide a circuit board capable of eliminating a connection failure between terminals at the time of connection and ensuring a good conductive connection state, and achieving a fine pitch of terminals and space saving.

  In the circuit board, the plurality of grooves formed on the top surfaces of the plurality of first terminals are arranged on the same straight line, and the extending direction of each groove and the extending direction of the straight line are They may be parallel to each other.

  According to this configuration, when the circuit board and the connection board are connected via the flexible adhesive member, the flexible adhesive member is more smoothly discharged to the outside. Specifically, at the time of connection between the circuit board and the connection board, when a flexible adhesive member is arranged in the main flow path, most of them flow along the extending direction of the main flow path arranged first, It is discharged outside. At this time, a part of the flexible adhesive member enters the branch channel branched from the main channel. Then, the flexible adhesive member that has entered the branch channel flows into the adjacent main channel across the first terminal. Then, the flexible adhesive member disposed in the adjacent main flow path is not aligned with the extending direction of the adjacent main flow path, but rather the branch flow path disposed on the same straight line as the first branch flow path. It becomes easy to flow into. The flexible adhesive member that has entered the branch channel flows into the main channel adjacent to the first terminal. Then, the flexible adhesive member arranged in the further adjacent main flow path has a branch arranged on the same straight line as the second branch flow path rather than flowing along the extending direction of the adjacent main flow path. It becomes easy to flow into the flow path. Hereinafter, the flexible adhesive member is discharged outside while repeating the above-described flow. As a result, the flexible adhesive member reaches the entire discharge path formed by the main channel and the branch channel. For this reason, a flexible adhesive member can be smoothly discharged | emitted compared with the case where the some groove | channel formed in the upper surface of several 1st terminal is irregularly arrange | positioned. Therefore, the connection failure between the terminals at the time of connection can be eliminated, and a good conductive connection state can be reliably ensured.

  In the circuit board, the plurality of grooves formed on the top surfaces of the plurality of first terminals include a plurality of grooves disposed on one side across an axis parallel to the extending direction of the first terminals. A first groove and a plurality of second grooves arranged on the other side are included, and the plurality of first grooves are arranged on the same first straight line extending in parallel with the extending direction of each first groove. The plurality of second grooves are arranged on the same second straight line extending in parallel with the extending direction of each second groove, and the extending direction of the first straight line and the second straight line are The extending direction may be arranged so as to intersect with each other, and the first straight line and the second straight line may be axisymmetric with respect to the axis.

  According to this configuration, when the plurality of grooves formed on the upper surfaces of the plurality of first terminals are arranged on the same straight line, the circuit board and the connection board are connected via the flexible adhesive member. In addition, the flexible adhesive member can be discharged to the outside more smoothly. Specifically, consider a case where a flexible adhesive member is disposed at the end of the main flow path passing on an axis parallel to the extending direction of the first terminal when the circuit board and the connection board are connected. Then, most of them flow along the extending direction of the main flow path passing on the axis, and are discharged to the outside. At this time, a part of the flexible adhesive member enters the bi-directional branch channel (first groove and second groove) branched from the main channel passing on the axis. Then, the flexible adhesive member that has entered the bi-directional branch channel flows into the adjacent main channel with the first terminal interposed therebetween. Then, the flexible adhesive member arranged in the adjacent main channel is arranged on the same straight line as the branch channel in the two directions entering first, rather than flowing along the extending direction of the adjacent main channel. It becomes easy to flow into the branch channel. The flexible adhesive member that has entered the branch channel flows into the main channel adjacent to the first terminal. Then, the flexible adhesive member arranged in the further adjacent main flow path is collinear with the branch passage in the second direction that enters the second, rather than flowing along the extending direction of the adjacent main flow path. It becomes easy to flow into the arranged branch channel. Hereinafter, the flexible adhesive member is discharged outside while repeating the above-described flow. As a result, the flexible adhesive member flows so as to be line-symmetric with respect to the shaft, and reaches the entire discharge path. For this reason, a flexible adhesive member can be smoothly discharged | emitted outside compared with the case where the several groove | channel formed in the upper surface of several 1st terminal is arrange | positioned on the same straight line. Therefore, the connection failure between the terminals at the time of connection can be eliminated, and a good conductive connection state can be reliably ensured.

  Further, in the circuit board, the plurality of grooves formed on the upper surfaces of the plurality of first terminals are arranged with the plurality of grooves arranged on one side across an axis parallel to the extending direction of the first terminals. The shape of the first groove group and the shape of the second groove group when divided into a first groove group consisting of grooves and a second groove group consisting of the plurality of grooves arranged on the other side May be line-symmetric with respect to the axis.

  According to this configuration, when the circuit board and the connection board are connected via the flexible adhesive member, the flexible adhesive member is symmetrical with respect to the axis parallel to the extending direction of the first terminal. It flows to the whole discharge route. Specifically, since the shape of the first groove group on one side and the shape of the second groove group on the other side with respect to the shaft are axisymmetric, the one side and the other side with respect to the shaft Thus, there is no variation in the shape of the discharge path. For this reason, a flexible adhesive member can be smoothly discharged | emitted outside so that it may become uniform between one side and the other side on both sides of the said axis | shaft. Therefore, the connection failure between the terminals at the time of connection can be eliminated, and a good conductive connection state can be reliably ensured.

  The connection structure of the present invention is provided between the circuit board according to the present invention described above, a connection board provided with a second terminal corresponding to the first terminal, and the circuit board and the connection board, An insulating adhesive member that maintains a state in which the first terminal and the second terminal are in conductive contact with each other.

  According to this configuration, since the circuit board described above is provided, the flexible adhesive member is discharged to the outside through the main channel and the branch channel formed by the plurality of first terminals at the time of connection. Thereby, an adhesive member does not intervene between the 1st terminal and the 2nd terminal, and the poor contact between terminals at the time of connection does not arise. Also, since the conductive contact state between the first terminal and the second terminal is held by the insulating adhesive member, the connection failure between the terminals at the time of connection is eliminated and a good conductive connection state is secured. Yes. In this embodiment, when the circuit board and the connection board are connected, an anisotropic conductive film (hereinafter referred to as ACF) or an anisotropic conductive paste (hereinafter referred to as ACF) is provided between the circuit board and the connection board as in the prior art. (Hereinafter referred to as ACP) is not interposed. For this reason, unlike the connection by ACF or ACP, there is no need to obtain conduction with the conductive particles in the resin, and the first terminal arranged on the circuit board can be made thin. Therefore, it is possible to provide a connection structure that can eliminate a connection failure between terminals at the time of connection and ensure a good conductive connection state, and can achieve a fine pitch of terminals and space saving of a circuit board.

1 is a schematic configuration diagram of an electro-optical device which is an example of a connection structure according to the present invention. It is a principal part enlarged view of the circuit board based on this invention. It is principal part sectional drawing of an electro-optical apparatus. It is process drawing which shows the manufacturing method of the connection structure which concerns on this invention in order. It is a top view which shows an example of the discharge route of the adhesive member at the time of a connection. It is a figure which shows the 1st modification of the circuit board based on this invention. It is a figure which shows the 2nd modification of the circuit board based on this invention.

  Embodiments of the present invention will be described below with reference to the drawings. This embodiment shows one aspect of the present invention, and does not limit the present invention, and can be arbitrarily changed within the scope of the technical idea of the present invention. Moreover, in the following drawings, in order to make each structure easy to understand, an actual structure and a scale, a number, and the like in each structure are different.

(Connection structure)
FIG. 1 is a schematic view showing a liquid crystal display device to which a connection structure according to the present invention is applied. First, an application example of the connection structure according to the present invention will be described with reference to FIG.
In FIG. 1, reference numeral 1 denotes a liquid crystal display device. The liquid crystal display device 1 includes a liquid crystal panel 2 and a circuit board 3. Although not shown, the liquid crystal display device 1 is appropriately provided with incidental members such as a polarizing plate, a reflection sheet, and a backlight as necessary.

  The liquid crystal panel 2 includes a connection substrate 10 and a counter substrate 20 made of glass or synthetic resin. The connection substrate 10 and the counter substrate 20 have a rectangular shape in plan view, are disposed to face each other, and are bonded to each other by a sealing material (not shown). A liquid crystal (not shown) that is an electro-optical material is sealed between the connection substrate 10 and the counter substrate 20. A first electrode (not shown) made of a transparent conductive material such as ITO (Indium Tin Oxide) is formed on the inner surface of the connection substrate 10. A second electrode (not shown) disposed opposite to the first electrode is formed on the inner surface of the counter substrate 20.

  A display area Ad is provided in the center of the facing area where the connection substrate 10 and the facing substrate 20 face each other. In the display area Ad, a plurality of scanning lines 12 extending in the X direction and a plurality of data lines 11 extending in the Y direction are provided in a lattice shape in plan view. Sub-pixels corresponding to any one of red, green, and blue are provided at the intersections between the scanning lines 12 and the data lines 11. On the connection substrate 10, such sub-pixels are arranged in a matrix, and the display region Ad as a whole is formed by the plurality of sub-pixels. Each sub-pixel is provided with a pixel switching element such as a TFT (Thin Film Transistor), which is not shown in FIG.

  The connection substrate 10 is provided with an overhanging portion 10 c that is a portion that protrudes outward from the outer shape of the counter substrate 20 at its end. The overhang portion 10c is provided with a plurality of second terminals 19 that are electrically connected to the scanning lines 12 and the data lines 11 via unillustrated routing wires.

  The circuit board 3 according to the present invention is connected to the overhanging portion 10 c via an insulating adhesive member 35. The plurality of second terminals 19 on the overhanging portion 10 c are conductively connected to the corresponding first terminals 40 provided on the base substrate 30 of the circuit board 3. In the present invention, the anisotropic conductive film (hereinafter referred to as ACF) and the anisotropic conductive paste (hereinafter referred to as ACP) shown in the prior art are not interposed between the overhanging portion 10c and the base substrate 30, The second terminal 19 and the first terminal 40 are in direct conductive contact. Thereby, the connection structure of the present invention in which the circuit board 3 is connected to the connection board 10 is formed.

  As the type of the adhesive member 35, a reactive curable adhesive, a thermosetting adhesive, a photocurable adhesive (ultraviolet curable adhesive), an anaerobic curable adhesive, and other various curable adhesives may be used. Can do. Specifically, acrylic adhesives, epoxy adhesives, silicone adhesives, natural rubber adhesives, polyurethane adhesives, phenolic adhesives, vinyl acetate adhesives, cyanoacrylate adhesives, polyvinyl alcohol A system adhesive, a polyimide system adhesive, a polyamide system adhesive, etc. can be used. These may be modified according to the purpose.

  The circuit board 3 is supplied with a control signal, a video signal, a power supply potential, and the like from the outside. Control signals, video signals, power supply potentials, and the like supplied to the circuit board 3 are input to an electronic component (not shown) mounted on the circuit board 3 (for example, a liquid crystal driving IC chip that drives the liquid crystal panel 2). A driving signal for driving the liquid crystal is generated and supplied to the liquid crystal panel 2 via the first terminal 40 and the second terminal 19.

  The circuit board 3 is, for example, a flexible board (hereinafter referred to as FPC). The FPC is a flexible organic substrate such as polyimide or liquid crystal polymer, and a circuit pattern and a first terminal 40 are formed on the base substrate 30 with copper or aluminum.

  According to the liquid crystal display device 1 configured as described above, an appropriate voltage is applied between the first electrode and the second electrode via the circuit board 3 so that both electrodes are arranged to face each other. The light can be modulated independently for each pixel configured in the above. Thereby, a desired image can be formed in the display area Ad of the liquid crystal panel 2.

Next, an embodiment of the circuit board 3 of the present invention applied to the liquid crystal display device 1 will be described.
FIG. 2 is an enlarged view of a main part showing the circuit board 3 in the liquid crystal display device 1 in an enlarged manner. 2A is an enlarged plan view of a main part showing the circuit board 3 in the liquid crystal display device 1 in an enlarged manner, and FIG. 2B is a cross-sectional view taken along line AA in FIG. is there.

  By the way, in order to eliminate poor connection between terminals at the time of connection and ensure a good conductive connection state, and to reduce the pitch of electrodes and save space on a printed circuit board, a pair of conductors are substantially flat. There is a structure in which conductors are joined together by metal bonding and the periphery thereof is joined by a thermosetting adhesive in an overlapping region of planar multiconductors arranged in alignment with various members. Further, irregularities are formed on the top surface of the planar multiconductor conductor so as to be able to penetrate the adhesive layer (see, for example, Patent Documents 1 and 2). However, since the concave and convex portions formed on the upper surface of the conductor are orthogonal to the discharge direction of the adhesive used when connecting the planar multiconductor, the adhesive is discharged when connecting the planar multiconductor. There is a possibility of being obstructed by the concave portion formed on the upper surface of the conductor. As a result, the adhesive is interposed between the pair of conductors, which may cause connection failure.

  Therefore, the inventor of the present application arranges a plurality of first terminals 40 extending in parallel with each other on the base substrate 30 with respect to the structures shown in Patent Documents 1 and 2, and upper surfaces of the plurality of first terminals 40. In addition, by providing the grooves 41 obliquely intersecting with the extending direction of the respective first terminals 40, the uncured or semi-cured adhesive member 35 is discharged when the circuit board 3 and the base substrate 30 are connected, The connection failure between the first terminal 40 and the second terminal 19 can be eliminated. Hereinafter, the circuit board 3 of the present embodiment will be described with an example.

  As shown in FIG. 2, the circuit board 3 includes a base substrate 30 and a plurality of first terminals 40 that extend in parallel to each other on the base substrate 30, and the plurality of first terminals 40. A groove 41 is formed on the upper surface of the first substrate 40. The grooves 41 obliquely intersect the extending direction of the first terminals 40. The width (length in the short direction) of the first terminal 40 is, for example, 20 to 30 μm.

  The plurality of first terminals 40 extend in the Y direction in parallel with each other in plan view. The plurality of grooves 41 formed on the upper surfaces of the plurality of first terminals 40 respectively extend in the XY directions in plan view. And the recessed part 42 between the two adjacent 1st terminals 40 becomes the main flow path of the non-hardened or semi-hardened flexible adhesive member 35 at the time of adhesion | attachment. Here, this flow path is a path through which most of the flexible adhesive member 35 flows during bonding. Further, the plurality of grooves 41 communicate with the recesses 42 (main flow paths), respectively, and serve as branch flow paths for the flexible adhesive member 35 during bonding. Here, the branch flow path is an auxiliary flow path that allows the flexible adhesive member 35 overflowing from the main flow path at the time of bonding to flow to the adjacent main flow path with the first terminal 40 interposed therebetween. The plurality of recesses 42 and the plurality of grooves 41 form a discharge path through which the flexible adhesive member 35 is discharged to the outside during bonding.

  Thereby, when connecting the circuit board 3 and the connection board | substrate 10, the flexible adhesive member 35 comes to be discharged | emitted smoothly outside. Specifically, when the flexible adhesive member 35 is disposed in the recess 42 (main flow path) when the circuit board 3 and the connection substrate 10 are connected, the extension of the recess 42 in which most of them are initially disposed. It flows along the current direction (Y direction) and is discharged to the outside. At this time, a part of the flexible adhesive member 35 enters the branch channel branched from the main channel. The amount of the flexible adhesive member 35 that enters the branch channel is smaller than the amount of the flexible adhesive member 35 that is first discharged from the main channel. The flexible adhesive member 35 that has entered the branch channel flows into the adjacent main channel with the first terminal 40 interposed therebetween. Next, the flexible adhesive member 35 disposed in the adjacent main flow path flows along the extending direction (Y direction) of the adjacent main flow path and is discharged to the outside. Thereafter, the flexible adhesive member 35 is discharged outside while repeating the above-described flow. The amount of the flexible adhesive member 35 that enters the branch flow path is the pressure applied when connecting the circuit board 3 and the connection board 10, the amount and viscosity of the flexible adhesive member 35 disposed in the recess 42, and the connection time. It varies depending on conditions such as the atmosphere.

  As described above, since the branch channel is formed so as to intersect obliquely (XY direction) with respect to the extending direction (Y direction) of the main channel, the flow of the flexible adhesive member 35 is changed to Patent Documents 1 and 2. Compared to the structure in which the concave and convex portions formed on the upper surface of the conductor are orthogonal to the discharge direction of the adhesive used when connecting the planar multiconductor, the flexible adhesive member 35 is discharged by the concave portions. It can be smoothly discharged outside without being obstructed.

  The plurality of grooves 41 formed on the top surfaces of the plurality of first terminals 40 are arranged on the same straight line SL. Further, the extending direction of each groove 41 (XY direction) and the extending direction of the straight line SL (XY direction) are parallel to each other. Here, the straight line SL is a virtual line. Specifically, as shown in FIG. 2A, when the six first terminals 40 extend in parallel to each other on the base substrate 30, six grooves 41 are formed on the same straight line SL. ing. The angle formed between the extending direction of the first terminal 40 and the direction in which the plurality of grooves 41 are formed on the same straight line SL is, for example, about 45 °.

  Thereby, when connecting the circuit board 3 and the connection board | substrate 10, the flexible adhesive member 35 comes to be discharged | emitted more smoothly outside. Specifically, when the flexible adhesive member 35 is disposed in the recess 42 (main flow path) when the circuit board 3 and the connection substrate 10 are connected, the extension of the recess 42 in which most of them are initially disposed. It flows along the current direction (Y direction) and is discharged to the outside. At this time, a part of the flexible adhesive member 35 enters the branch channel branched from the main channel. The flexible adhesive member 35 that has entered the branch channel flows into the adjacent main channel with the first terminal 40 interposed therebetween. Then, the flexible adhesive member 35 arranged in the adjacent main flow path is on the same straight line SL as the branch flow path that has entered first, rather than flowing along the extending direction (Y direction) of the adjacent main flow path. It becomes easy to flow into the arranged branch channel. The flexible adhesive member 35 that has entered the branch channel flows into the adjacent main channel with the first terminal 40 interposed therebetween. Then, the flexible adhesive member 35 arranged in the further adjacent main flow path is collinear with the branch flow path that enters the second, rather than flowing along the extending direction (Y direction) of the further adjacent main flow path. It becomes easy to flow into the branch channel disposed above. Thereafter, the flexible adhesive member 35 is discharged outside while repeating the above-described flow. As a result, the flexible adhesive member 35 reaches the entire discharge path. For this reason, compared with the case where the plurality of grooves 41 formed on the upper surfaces of the plurality of first terminals 40 are not arranged on the same straight line but are irregularly arranged, the flexible adhesive member 35 is smoothly discharged to the outside. can do.

  The first terminal 40 may have a conductive film (not shown) formed on the surface thereof. The conductive film is made of metal or alloy such as Au, Sn, TiW, Cu, Cr, Ni, Ti, W, NiV, Al, Pd, lead-free solder. Further, the conductive film may be a single layer of these metals (alloys) or a laminate of a plurality of types. In addition, such a conductive film may be formed by a known film formation method such as a sputtering method, and then patterned in accordance with the shape of the main body, and is selectively formed by electroless plating. It may be a thing. Alternatively, a base film may be formed by sputtering or electroless plating, and then an upper layer film may be formed on the base film by electrolytic plating, and a conductive film may be formed by a laminated film including these base film and upper layer film. . Note that the type, layer structure, film thickness, and covering region of the metal (alloy) are appropriately selected and designed according to the shape and size of the first terminal 40. In the present embodiment, a first terminal made of copper is formed, and a conductive film made of gold is formed on the surface thereof.

  FIG. 3 is a cross-sectional view of a main part of the liquid crystal display device 1 which is an example of the connection structure according to the present invention. In FIG. 3, for the sake of convenience, the illustration of the counter substrate 20 constituting the liquid crystal panel 2 is omitted, and the end portion of the connection substrate 10 (part of the protruding portion 10 c provided with the second terminals 19) and the circuit substrate 3. 2 (a part of the base substrate 30 provided with the first terminals 40).

  As shown in FIG. 3, the liquid crystal display device 1 is provided between the circuit board 3, the connection board 10, the circuit board 3 and the connection board 10, and the first terminal 40 and the second terminal 19 are provided. And an insulating adhesive member 35 that holds the conductive contact state.

  Since the circuit board 3 described above is provided, the flexible adhesive member 35 is discharged to the outside through the main channel and the branch channel formed by the plurality of first terminals 40 at the time of connection. As a result, the adhesive member 35 is not interposed between the first terminal 40 and the second terminal 19, so that contact failure between the terminals at the time of connection does not occur. In addition, since the state where the first terminal 40 and the second terminal 19 are in conductive contact is held by the insulating adhesive member 35, the connection failure between the terminals at the time of connection is eliminated and a good conductive connection state is obtained. It is secured.

  Further, in the present embodiment, when the circuit board 3 and the connection board 10 are connected, the above-described adhesive member 35 made of an acrylic adhesive or the like is used, and between the circuit board and the connection board as in the prior art. An anisotropic conductive film (hereinafter referred to as ACF) and an anisotropic conductive paste (hereinafter referred to as ACP) are not interposed. For this reason, unlike the connection by ACF or ACP, there is no need to obtain conduction with the conductive particles in the resin, and the first terminal arranged on the circuit board can be made thin.

(Method for manufacturing connection structure)
Hereinafter, a method for manufacturing the liquid crystal display device 1 according to the present embodiment will be described. FIG. 4 is a process diagram sequentially illustrating a manufacturing method of the liquid crystal display device 1, and FIG. 5 is a plan view illustrating an example of a discharge route of the flexible adhesive member 35 at the time of connection. FIG. 5 is an enlarged plan view showing a main part of the circuit board 3 in the liquid crystal display device corresponding to FIG. In FIG. 5, the same elements as those in FIG. 2A are denoted by the same reference numerals, and detailed description thereof is omitted.

  First, as shown in FIG. 4A, a base substrate 30 manufactured by a method similar to the conventional one is prepared. As the base substrate 30, for example, a flexible organic substrate such as polyimide or liquid crystal polymer can be used.

  Next, a conductive layer 40A made of a conductive material (copper in this embodiment) is formed in a predetermined shape on the connection side of the base substrate 30 by a known lithographic technique or etching technique. Here, a plurality of conductive layers 40 </ b> A are formed in parallel in the plane of the base substrate 30, and are arranged at intervals.

  Next, the first terminal 40 is formed by pressing the press die 50 against the conductive layer 40A. Here, the press die 50 in which the convex part 51 corresponding to the groove | channel 41 which cross | intersects diagonally with respect to the extension direction of the 1st terminal 40 mentioned above is used.

  By using the press die 50, the convex portions 51 are pressed against the conductive layer 40 </ b> A, thereby crossing the upper surfaces of the plurality of first terminals 40 obliquely with respect to the extending directions of the first terminals 40. A groove 41 is formed. As a result, the first terminal 40 made of copper is formed (see FIG. 4B).

  Next, if necessary, the conductive film described above is formed on the first terminal 40 formed on the base substrate 30 by a known film formation method such as a sputtering method, and then the shape of the main body is formed. The pattern is formed by following the above or selectively disposed by electroless plating. Alternatively, a base film may be formed by sputtering or electroless plating, and then an upper layer film may be formed on the base film by electrolytic plating, and a conductive film may be formed by a laminated film including these base film and upper layer film. . As a result, a conductive film (not shown) is formed on the surface of the first terminal 40. Here, gold is used as a material for forming the conductive film.

  Next, as shown in FIG. 4C, a connection board 10 manufactured by a method similar to the conventional one is prepared. A second terminal 19 is provided on the connection substrate 10 at a position corresponding to the first terminal 40. Next, the above-described adhesive member 35 is disposed on the connection substrate 10. At this time, the adhesive member 35 is in an uncured or semi-cured state (a state before being completely cured), and is sufficiently softer than the first terminal 40. Next, the circuit board 3 and the connection board 10 are positioned so that the first terminals 40 and the second terminals 19 face each other.

  Next, in the positioned state, the circuit board 3 and the connection board 10 are pressed in a direction in which the first terminal 40 and the second terminal 19 are in conductive contact with each other. Then, since the uncured or semi-cured adhesive member 35 is sufficiently softer than the first terminal 40, the uncured or semi-cured adhesive member 35 is pushed away by the convex portion between the grooves 41 of the first terminal 40 when pressed. At this time, most of the flexible adhesive member 35 pushed away by the convex portion between the grooves 41 of the first terminal 40 flows into the concave portion 42 between the two adjacent first terminals 40, and the rest are plural. Into the groove 41. Thereafter, by continuing the pressurization, the flexible adhesive member 35 is crushed. The flexible adhesive member 35 is discharged to the outside by the discharge path formed by the plurality of recesses 42 and the plurality of grooves 41.

  Here, the discharge route of the flexible adhesive member 35 at the time of connection will be described with reference to FIG. At the time of connection between the circuit board 3 and the connection board 10, a part 35 a (hereinafter referred to as an adhesive fluid) of the flexible adhesive member 35 is disposed in the recess 42 (main flow path 42 a) in the center of the circuit board 3. Consider the case. Then, most of the adhesive fluid 35a disposed in the central portion of the main flow path 42a flows along the extending direction (Y direction) of the main flow path 42a and is discharged to the outside. Further, the adhesive fluid 35a disposed in the central portion of the main flow path 42a is discharged in two directions of one direction (+ Y direction) and the other direction (−Y direction). Here, the adhesive fluid 35a discharged in one direction (+ Y direction) is considered. Then, a part of the adhesive fluid 35a enters the branch channel 41a branched from the main channel 42a. Then, the adhesive fluid 35a that has entered the branch channel 41a flows into the adjacent main channel 42b with the first terminal 40 interposed therebetween. Then, the adhesive fluid 35a disposed in the main flow path 42b flows along the extending direction (+ Y direction) of the main flow path 42b, and the branch disposed on the same straight line SL as the branch flow path 41a that enters first. It flows into the flow path 41b. The adhesive fluid 35a that has entered the branch channel 41b flows into the adjacent main channel 42c with the first terminal 40 interposed therebetween. Thereafter, the adhesive fluid 35a is discharged to the outside while repeating the above-described flow. The adhesive fluid 35a discharged in the other direction (−Y direction) among the adhesive fluid 35a disposed in the central portion of the main flow path 42a is similar to the adhesive fluid 35a discharged in one direction (+ Y direction). The flow is repeated. As a result, the adhesive fluid 35a reaches the entire discharge path. For this reason, compared with the case where the some groove | channel 41 formed in the upper surface of the some 1st terminal 40 is arrange | positioned irregularly, it can discharge | emit smoothly outside.

  In this way, as shown in FIG. 4D, the circuit board 3 and the connection board 10 are bonded to the uncured or semi-cured adhesive member 35 so that the first terminal 40 and the second terminal 19 are in conductive contact. Are joined together. Then, the adhesive member 35 described above is completely cured in a state where the first terminal 40 and the second terminal 19 are in conductive contact. Through the above steps, the liquid crystal display device 1 of the present embodiment is obtained.

  According to the circuit board 3 according to the present invention, when the circuit board 3 and the connection board 10 are connected, the flexible adhesive member 35 is smoothly discharged to the outside. Specifically, when the flexible adhesive member 35 is disposed in the recess 42 (main flow path) when the circuit board 3 and the connection substrate 10 are connected, the extension of the recess 42 in which most of them are initially disposed. It flows along the current direction (Y direction) and is discharged to the outside. At this time, a part of the flexible adhesive member 35 enters the branch channel branched from the main channel. The flexible adhesive member 35 that has entered the branch channel flows into the adjacent main channel with the first terminal 40 interposed therebetween. Next, the flexible adhesive member 35 disposed in the adjacent main flow path flows along the extending direction (Y direction) of the adjacent main flow path and is discharged to the outside. Thereafter, the flexible adhesive member 35 is discharged outside while repeating the above-described flow. As described above, since the branch channel is formed so as to intersect obliquely (XY direction) with respect to the extending direction (Y direction) of the main channel, the flow of the flexible adhesive member 35 is changed to Patent Documents 1 and 2. Compared to the structure in which the concave and convex portions formed on the upper surface of the conductor are orthogonal to the discharge direction of the adhesive used when connecting the planar multiconductor, the flexible adhesive member 35 is discharged by the concave portions. It can be smoothly discharged outside without being obstructed. Therefore, it is possible to provide a circuit board 3 that can eliminate a connection failure between terminals at the time of connection and ensure a good conductive connection state, and can achieve a fine pitch of terminals and space saving.

  Moreover, according to the circuit board 3 according to the present invention, since the plurality of grooves 41 formed on the upper surfaces of the plurality of first terminals 40 are arranged on the same straight line SL, the circuit board 3 and the connection board 10 are connected to each other. When connecting, the flexible adhesive member 35 is more smoothly discharged to the outside. Specifically, when the flexible adhesive member 35 is disposed in the recess 42 (main flow path) when the circuit board 3 and the connection substrate 10 are connected, the extension of the recess 42 in which most of them are initially disposed. It flows along the current direction (Y direction) and is discharged to the outside. At this time, a part of the flexible adhesive member 35 enters the branch channel branched from the main channel. The flexible adhesive member 35 that has entered the branch channel flows into the adjacent main channel with the first terminal 40 interposed therebetween. Then, the flexible adhesive member 35 arranged in the adjacent main flow path is on the same straight line SL as the branch flow path that has entered first, rather than flowing along the extending direction (Y direction) of the adjacent main flow path. It becomes easy to flow into the arranged branch channel. The flexible adhesive member 35 that has entered the branch channel flows into the adjacent main channel with the first terminal 40 interposed therebetween. Then, the flexible adhesive member 35 arranged in the further adjacent main flow path is collinear with the branch flow path that enters the second, rather than flowing along the extending direction (Y direction) of the further adjacent main flow path. It becomes easy to flow into the branch channel disposed above. Thereafter, the flexible adhesive member 35 is discharged outside while repeating the above-described flow. As a result, the flexible adhesive member 35 reaches the entire discharge path. For this reason, compared with the case where the some groove | channel 41 formed in the upper surface of the some 1st terminal 40 is arrange | positioned irregularly, the flexible connection member 35 can be discharged | emitted smoothly outside. Therefore, the connection failure between the terminals at the time of connection can be eliminated, and a good conductive connection state can be reliably ensured.

  Further, according to the liquid crystal display device 1 according to the present invention, since the circuit board 3 described above is provided, the main flow path and the branch flow path in which the flexible adhesive member 35 is formed by the plurality of first terminals 40 at the time of connection. Is discharged to the outside. As a result, the adhesive member 35 is not interposed between the first terminal 40 and the second terminal 19, so that contact failure between the terminals at the time of connection does not occur. In addition, since the state where the first terminal 40 and the second terminal 19 are in conductive contact is held by the insulating adhesive member 35, the connection failure between the terminals at the time of connection is eliminated and a good conductive connection state is obtained. It is secured. Further, in the present embodiment, when the circuit board 3 and the connection board 10 are connected, the above-described adhesive member 35 made of an acrylic adhesive or the like is used, and between the circuit board and the connection board as in the prior art. An anisotropic conductive film (hereinafter referred to as ACF) and an anisotropic conductive paste (hereinafter referred to as ACP) are not interposed. For this reason, unlike the connection by ACF or ACP, there is no need to obtain conduction with the conductive particles in the resin, and the first terminal arranged on the circuit board can be made thin. Therefore, it is possible to provide the liquid crystal display device 1 capable of eliminating the connection failure between the terminals at the time of connection and ensuring a good conductive connection state, and reducing the fine pitch of the terminals and saving the space of the circuit board 3. .

  In addition, although this embodiment demonstrated the example in which the some groove | channel 41 formed in the upper surface of the some 1st terminal 40 is arrange | positioned on the same straight line, it is not restricted to this. Hereinafter, a modified example different from the above embodiment will be described with reference to FIGS.

(First modification)
FIG. 6 is a view showing a first modification of the circuit board according to the present invention. FIG. 6A is an enlarged plan view of a main part showing an enlarged circuit board 3A in the liquid crystal display device corresponding to FIG. 2A, and FIG. It is B line arrow sectional drawing. 6, elements similar to those in FIG. 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 6, in the circuit board 3 </ b> A of this modification, the plurality of grooves 141 formed on the upper surfaces of the plurality of first terminals 140 are parallel to the extending direction (Y direction) of the first terminals 140. A plurality of first grooves 141a arranged on one side (+ X direction side from the axis CL1) and a plurality of second grooves arranged on the other side (−X direction side from the axis CL1) across the axis CL1 141b is included. A plurality of first grooves 141a are arranged on the same first straight line SL1 extending in parallel with the extending direction of each first groove 141a. A plurality of second grooves 141b are arranged on the same second straight line SL2 extending in parallel with the extending direction of each second groove 141b. Further, the extending direction of the first straight line SL1 and the extending direction of the second straight line SL2 intersect, and the first straight line SL1 and the second straight line SL2 are symmetric with respect to the axis CL1. ing.

  According to the circuit board 3A of the present modification, the circuit board 3 and the connection board 10 are compared with the case where the plurality of grooves 41 formed on the upper surfaces of the plurality of first terminals 40 are arranged on the same straight line SL. When connecting the flexible adhesive member 35, the flexible adhesive member 35 is more smoothly discharged to the outside. Specifically, when the circuit board 3 and the connection board 10 are connected, the flexible adhesive member 35 is at the end (−Y direction side) of the recess 142 (main flow path) that passes over the axis CL1 in the circuit board 3. Consider the case where it is placed. Then, most of them flow along the extending direction (Y direction) of the main flow path passing on the axis CL1, and are discharged to the outside. At this time, a part of the flexible adhesive member 35 enters the bi-directional branch channel (the first groove 141a and the second groove 141b) branched from the main channel passing on the axis CL1. The flexible adhesive member 35 that has entered the bi-directional branch channel flows into the adjacent main channel with the first terminal 140 interposed therebetween. Then, the flexible adhesive member 35 arranged in the adjacent main flow path is the same as the branch flow path in the two directions that entered first, rather than flowing in the extending direction (Y direction) of the adjacent main flow path. It becomes easy to flow into the branch flow paths arranged on the straight lines SL1 and SL2. The flexible adhesive member 35 that has entered the branch flow channel flows into the adjacent main flow channel with the first terminal 140 interposed therebetween. Then, the flexible adhesive member 35 arranged in the further adjacent main flow path and the bi-directional branch flow path that enters the second direction rather than flowing in the extending direction (Y direction) of the further adjacent main flow path It becomes easy to flow into the branch flow paths arranged on the same straight lines SL1 and SL2, respectively. Thereafter, the flexible adhesive member 35 is discharged outside while repeating the above-described flow. Thereby, the flexible adhesive member 35 flows so as to be line-symmetric with respect to the axis CL1, and reaches the entire discharge path. For this reason, compared with the case where the some groove | channel 41 formed in the upper surface of the some 1st terminal 40 is arrange | positioned on the same straight line SL, the flexible connection member 35 can be discharged | emitted smoothly outside. Therefore, the connection failure between the terminals at the time of connection can be eliminated, and a good conductive connection state can be reliably ensured.

(Second modification)
FIG. 7 is a view showing a second modification of the circuit board according to the present invention. FIG. 7A is an enlarged plan view of a main part showing an enlarged circuit board 3B in the liquid crystal display device corresponding to FIG. 2A, and FIG. FIG. In FIG. 7, elements similar to those in FIG. 2 are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 7, in the circuit board 3 </ b> B of this modification, the plurality of grooves 241 formed on the top surfaces of the plurality of first terminals 240 are parallel to the extending direction (Y direction) of the first terminals 240. A first groove group 241a composed of a plurality of grooves 241 disposed on one side (+ X direction side from the axis CL2) across the axis CL2 and the other side (−X direction side from the axis CL2). When divided into a second groove group 241b composed of a plurality of grooves 241, the shape of the first groove group 241a and the shape of the second groove group 241b are line symmetric with respect to the axis CL2. Yes. That is, the shape of the plurality of grooves 241 disposed on one side (the + X direction side from the axis CL2) and the plurality of grooves disposed on the other side (the −X direction side from the axis CL2) across the axis CL2. The shape of 241 is line-symmetric with respect to the axis CL2.

  According to the circuit board 3B of the present modification, when the circuit board 3 and the connection board 10 are connected, the flexible adhesive member 35 flows so as to be symmetric with respect to the axis CL2, and spreads over the entire discharge path. become. Specifically, since the shape of the first groove group 241a on one side and the shape of the second groove group 241b on the other side with respect to the axis CL2 are axisymmetric, the one side and the other side with respect to the axis CL2 There is no variation in the shape of the discharge path between the two sides. For this reason, the flexible adhesive member 35 can be smoothly discharged to the outside so as to be uniform between the one side and the other side across the axis CL2. Therefore, the connection failure between the terminals at the time of connection can be eliminated, and a good conductive connection state can be reliably ensured.

DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display device (connection structure) 3, 3A, 3B ... Circuit board, 10 ... Connection board, 30 ... Base board, 35 ... Adhesive member, 40, 140, 240 ... First terminal, 41, 141, 241 ... groove, 42, 142, 242 ... concave, 141a ... first groove, 141b ... second groove, 241a ... first groove group, 241b ... second groove group, CL1, CL2 ... extending direction of the first terminal , SL ... straight line, SL1 ... first straight line, SL2 ... second straight line

Claims (5)

A base substrate;
A plurality of first terminals extending in parallel with each other on the base substrate;
A circuit board characterized in that grooves are formed on the upper surfaces of the plurality of first terminals so as to obliquely intersect the extending direction of the first terminals.   The plurality of grooves formed on the top surfaces of the plurality of first terminals are arranged on the same straight line, and the extending direction of each groove and the extending direction of the straight line are parallel to each other. The circuit board according to claim 1.   The plurality of grooves formed on the top surfaces of the plurality of first terminals are arranged on the other side with a plurality of first grooves arranged on one side across an axis parallel to the extending direction of the first terminal. A plurality of second grooves, wherein the plurality of first grooves are arranged on the same first straight line extending in parallel with the extending direction of each first groove, and the plurality of second grooves Are arranged on the same second straight line extending in parallel with the extending direction of each second groove, and the extending direction of the first straight line and the extending direction of the second straight line intersect each other. The circuit board according to claim 1, wherein the circuit board is disposed and the first straight line and the second straight line are line-symmetric with respect to the axis.   A plurality of grooves formed on the upper surfaces of the plurality of first terminals, a first groove group including the plurality of grooves disposed on one side across an axis parallel to the extending direction of the first terminals. And the second groove group consisting of the plurality of grooves arranged on the other side, the shape of the first groove group and the shape of the second groove group are lines with the axis in between. The circuit board according to claim 1, wherein the circuit board is symmetrical. The circuit board according to any one of claims 1 to 4,
A connection board provided with a second terminal corresponding to the first terminal;
An insulating adhesive member that is provided between the circuit board and the connection board and maintains the conductive contact between the first terminal and the second terminal;
A connection structure comprising:

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