KR100777167B1 - Wiring connection structure and liquid crystal panel - Google Patents

Abstract

(assignment)

An object of the present invention is to provide a wiring connection structure and a liquid crystal display device capable of simplifying and sharing a wiring structure, and improving workability and connection reliability at the time of wiring connection.

(Solution)

This invention arrange | positions the ACF film of the structure which disperse | distributed the electroconductive particle to the binder of resin over an element connection area | region and an FPC wiring area | region, and the element provided with the connection terminal on the ACF film on an element connection area | region through an ACF film. It electrically connects to the wiring of an element connection area | region, and connects an FPC film to the connection wiring of the FPC wiring area | region on the ACF film on the FPC wiring area | region.

Description

Wiring connection structure and liquid crystal display device {WIRING CONNECTION STRUCTURE AND LIQUID CRYSTAL PANEL}

 1 is a perspective view of a liquid crystal display device showing a first embodiment of the present invention.

FIG. 2 is a partial cross-sectional view taken along line II-II of the liquid crystal display of FIG. 1.

3 is a cross-sectional view of an ACF film incorporated in the liquid crystal display device.

It is explanatory drawing which shows the state which manufactures the structure of this invention by one press head.

5 is a perspective view showing an example of a conventional liquid crystal display device.

FIG. 6 is a partial cross-sectional view taken along the line VII-VII of the liquid crystal display shown in FIG. 5.

7 is a plan view illustrating a connection region of a driving IC of a conventional liquid crystal display device and a connection region of a flexible printed circuit board.

It is explanatory drawing which shows the state which connects a drive IC to the wiring on a board | substrate through an ACF film in the conventional liquid crystal display device.

It is explanatory drawing which shows the state which connects a flexible printed circuit board with wiring on a board | substrate through an ACF film in the conventional liquid crystal display device.

(Explanation of the sign)

A: liquid crystal display

1: liquid crystal cell

2, 3: substrate

5: liquid crystal

6: sealing material

7: driving element connection area

8: FPC wiring area

9: driving element (driving IC)

9a, 9b: connection terminal

10: flexible printed circuit board

11: extension wiring

15: wiring section

16: ACF film

20: substrate

21: dispersion layer

22: conductive particles

23: binder

25: wiring section

26: pressurized head

[Patent Document 1] Japanese Unexamined Patent Publication No. 2004-61979

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connection structure of a wiring portion applied to a liquid crystal display device and the like, and more particularly, to a technique in which a flexible printed circuit board and a device such as a driving IC mounted on a substrate can be connected without a gap.

Generally, a liquid crystal display device is comprised from the liquid crystal panel which enclosed liquid crystal between the upper and lower transparent substrates, its driver circuit, and the circuit board electrically connected with the video signal processing apparatus. The driver circuit has a configuration in which a driving IC, a power supply component, or the like is mounted on a film substrate on which a predetermined wiring pattern is formed, and is generally configured as a flexible connection substrate connecting the liquid crystal panel and the circuit board.

As a connection method of a flexible connection board and a circuit board, in recent years, in order to improve the resolution of a liquid crystal display, the pitch space of the connection lead of a circuit board and the electrode pitch space of a connection board tend to be minutely formed, and a connection board The TAB (Tape Automated Bonding) mounting method using ACF (Anisotropic Conductive Film) is widely used for the connection between the printed circuit board and the printed circuit board.

ACF consists of disperse | distributing electroconductive particle to the binder of resin with adhesive force, and is normally formed in tape form. Then, the ACF tape is attached onto the connection lead of the circuit board, adhered to the ACF tape in a state in which the connection board is aligned with the printed circuit board, and first presses the connection board and the printed circuit board in the heated state, thereby bonding the binder. While softening and compressing the resin, the electrode of the connecting substrate and the connecting lead of the circuit board are electrically connected through conductive particles, and the binder resin is cured by further heating, thereby fixing the connection between the connecting board and the circuit board. It has a structure to complete the connection.

5 and 6 show an example of a general liquid crystal display device having a driver IC.

In the liquid crystal display device of this example, the driving IC 103 is mounted on one side of the pair of substrates 101 and 102 with the liquid crystal layer interposed therebetween by chip on glass (COG) mounting or the like. . It is necessary to connect one transparent electrode and the other transparent electrode of the paired board | substrate to this drive IC 103, and a board | substrate in the form which extends an extraction wiring by transparent conductive materials, such as indium tin oxide (ITO), is carried out. By forming on the 102, the drive IC 103 is connected to each transparent electrode.

Moreover, it is necessary to connect the flexible printed wiring board (FPC) 106 which connects the electric circuit etc. for supplying a drive signal to this drive IC 103, and conventionally, as shown in FIG. The connection wiring 104b is formed on the outer edge side of the connection by a transparent conductive material, and the driving IC 103 is connected to one end (near end of the substrate 102) of the connection wiring 104b. Then, the ACF film 107 is inserted between the other end (near the outer edge of the substrate) of the connection wiring 104b and the FPC 106 and heated and pressurized to connect the wiring wiring 104b and the FPC ( The wiring 106a of the 106 is electrically connected via the conductive particles in the ACF film 107.

However, the present inventors have a pair of substrates opposed to each other with a liquid crystal layer interposed therebetween, and mount the driving IC on the substrate and connect the driving IC and the flexible printed wiring board to the substrate on which the driving IC is mounted. Forming a wiring, connecting the driving IC to the end of the connecting wiring, arranging an ACF film in the vicinity of the driving IC, electrically connecting the connecting wiring and the flexible printed wiring board via the ACF film, and The patent application was applied about the liquid crystal display device of the structure which extended the edge part of the wiring pattern of a printed wiring board to the vicinity of a drive IC, and electrically connected the drive IC and the flexible printed wiring board (refer patent document 1).

As the structure which further developed the connection structure by the said COG mounting and ACF film, this inventor arrange | positions the ACF film 111 for COG in the lead-out wiring area side near the display area of the board | substrate 102 shown in FIG. On the (102), the ACF film 112 for FPC is arrange | positioned slightly outside of the said ACF film 111, the drive IC is crimp-connected to the ACF film 111, and FPC is crimped | bonded to the ACF film 112 A structure for connecting is adopted to simplify the wiring connection structure.

In the liquid crystal display device of the conventional structure shown in FIG. 5, FIG. 6, although the FPC106 is arrange | positioned between the drive IC 103 and the ACF film 107, the drive IC 103 and the ACF film 106 are shown. Since the gap 110 inevitably occurs between, the arrangement efficiency was bad in terms of the narrowing of the liquid crystal display device.

Moreover, even if the structure shown in FIG. 7 is employ | adopted, since the intersection at the time of the operation | work which affixes ACF films 111 and 112 on a board | substrate inevitably arises about ± 0.3 mm, ACF films 111 and 112 should be about at least 0.6 mm. It is necessary to detach and attach, and even in this area | region of about 0.6 mm width, it has become the useless area which cannot be neglected in the electronic device which miniaturizes, such as a mobile telephone.

Thus, what is needed about the minimum of +/- 0.3 mm of intersection at the time of attachment is when the connection terminal 121 of the drive IC 120 shown to FIG. 8 and FIG. 9 is pressed by the ACF film 111, Comparing the case where the connection terminal of the FPC 106 is pressed against the ACF film 107 and bonded, in comparison of the connection terminal 121 of the driving IC with the connection terminal of the FPC 106, the difference in the size and gap of the terminal is shown. Since the pressure is large and preferable conditions such as a press pressure and a temperature differ individually, after pressing and connecting the drive IC 120 with the pressurizing head 123 shown in FIG. 8, the other magnitude | size and a pressurization force shown in FIG. It is because it is necessary to press-connect the FPC 106 to the ACF film 107 by this other pressurizing head 124, and inevitably needs to form a little clearance in consideration of interference, clearance, etc. of both heads. .

In addition, the ACF film 111 for the connection terminal 121 of the driving IC 120 and the ACF film 107 for the FPC 106 are respectively formed by the connection terminal 121 of the driving IC 120. Since the connection terminal portion of the FPC 106 has a pitch of about 0.1 to 1 mm while the pitch number is 10 μm, the size and pitch of the terminals are different, and the pressing force on the ACF film is naturally different, the resin constituting the ACF film It is because it is necessary to prepare as each ACF film, since the viscosity of is also different and heat processing temperature also differs because of them.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and the wiring connection directly under an element and the wiring connection directly under an FPC can be performed by one ACF, thereby simplifying and sharing the wiring structure and improving workability at the time of wiring connection. An object of the present invention is to provide a wiring connection structure capable of improving the connection reliability.

In addition, the present invention simplifies and shares the wiring structure in the liquid crystal substrate, and at the time of wiring connection, by making the wiring connection directly under the liquid crystal drive element and the wiring connection directly under the FPC to be performed by one ACF. An object of the present invention is to provide a liquid crystal display device capable of improving workability and improving connection reliability.

Means to solve the problem

This invention is made | formed in view of the said situation, The element connection area | region and FPC wiring area | region are formed on a board | substrate, ACF of the structure which disperse | distributed electroconductive particle to the binder of resin over the said device connection area | region and said FPC wiring area | region. A film is disposed, and on the ACF film on the element connection region, an element having a connection terminal is provided in a state in which the connection terminal is electrically connected to the wiring of the element connection region via an ACF film. On the ACF film on a wiring area | region, an FPC film is provided in the state in which the wiring part is electrically connected to the connection wiring of the said wiring area for FPCs via an ACF film.

A liquid crystal display device of the present invention is provided with a pair of substrates facing each other with a liquid crystal layer interposed therebetween, and each of the wirings being formed on the surface of the liquid crystal layer side of each substrate. Wired to an element connection region of the one substrate, spaced apart from the element connection region at the periphery of the substrate to form an FPC wiring region, and a resin over both regions in the element connection region and the FPC wiring region ACF film of the structure which disperse | distributed the electroconductive particle to the binder of 2 is arrange | positioned, and the element provided with a connection terminal was connected to the wiring of the said element connection area | region through the ACF film on the ACF film on the said element connection area | region. While being installed in a state, an FPC film is formed on the ACF film on the wiring area for the FPC, and the wiring part is connected to the FPC wiring via the ACF film. It is characterized by being provided in the state connected to the reverse connection wiring.

In any of the above structures, the wiring connection directly under the element and the wiring connection directly under the FPC can be shared by one ACF, and the wiring structure can be simplified and shared, and the wiring connection can be made when using two ACF films. The workability at the time and the reliability of the connection can be improved. Moreover, compared with the case where each ACF film is arrange | positioned, since it does not need to press-press on each condition in the case of heating and crimping | bonding, there is no need to form the clearance at the time of crimping | bonding an ACF film, and A flexible printed circuit board can be arrange | positioned as close as possible.

The present invention is characterized in that the pitch and the thickness of the connecting terminal portion of the element and the pitch and the thickness of the FPC film wiring portion are different from each other.

The above-described structure can be applied even when the pitch of the part of the connection terminal of an element and the wiring part of an ACF film differ.

In the present invention, the connection terminal of the element is connected by thermal compression bonding to the wiring of the element connection region on the substrate via the conductive particles of the ACF film, and the wiring portion of the FPC film is interposed between the conductive particles of the ACF film. To be connected by thermal compression to the connection wiring of the wiring region for FPC on the substrate.

The present invention is characterized in that the binder is composed of an epoxy resin or an acrylic resin, the binder thickness is in the range of 20 to 25 µm, and the elastic modulus of the binder is 1.0 to 3.0 GPa.

If the thickness of the binder which consists of said resin is the said range, and an elasticity modulus is the said range, even if the connection terminal of an element and the electrode of a flexible printed circuit board have a structure with a different pitch or size, it can connect without a trouble.

The present invention is characterized in that the binder is made of an epoxy resin or an acrylic resin, and the thickness of the binder is in a range of 20 to 25 µm and the diameter of the conductive particles dispersed and blended in the binder is in the range of 3 to 5 µm. do.

If the thickness of the binder which consists of said resin is the said range, and the diameter of electroconductive particle is the said range, even if the connection terminal of an element and the electrode of a flexible printed circuit board have a structure with a different pitch or size, it can connect without a trouble.

The present invention is the binder is made of epoxy resin or acrylic resin, the binder thickness is 20 to 25㎛, the density of the conductive particles dispersed and blended in the binder is in the range of 1 million / ㎣ to 7.5 million / 이루어지는 It is characterized by.

If the thickness of the binder which consists of said resin is the said range, and the density of electroconductive particle is the said range, even if it is a structure in which the connection terminal of an element and the electrode of a flexible printed circuit board differ in pitch or size, it can connect without a trouble.

Implement the invention  Best form for

EMBODIMENT OF THE INVENTION Hereinafter, although embodiment of this invention is described with reference to drawings, this invention is not limited to embodiment described below. In addition, in the following drawings, the scale of each component is changed and described for every component so that it may become easy to write in the figure.

FIG. 1: is a perspective view which shows schematic structure of the liquid crystal display device of 1st Embodiment, and FIG. 2 is sectional drawing along the II-II line of the liquid crystal display device of FIG.

In the figure, 1 is a liquid crystal cell, and this liquid crystal cell 1 superimposes two transparent substrates 2 and 3 so as to form a cell gap therebetween, and injects the liquid crystal (injected between the substrates 2 and 3). 5) is made of the basic structure surrounded by the sealing material 6 formed in the peripheral edge part of the board | substrate 2 and 3 and these opposite surfaces. In FIG. 1, FIG. 2, the board | substrate 2 located in the lower side becomes a size larger than the board | substrate 3 of the upper side, and the drive element connection area | region 7 mentioned later to the extended part 2a of the board | substrate 2 is mentioned. ), An FPC wiring region 8 is formed, a driving element (driving IC) 9 is mounted in the driving element connection region 7, and a flexible printed circuit board (FPC) ( 10) is connected and the liquid crystal display device A is comprised.

The liquid crystal drive circuit provided in the liquid crystal cell 1 used in this form is not particularly limited, and either a simple matrix type or an active matrix type may be used. For example, a thin film transistor is arranged for each pixel partitioning the display area, and a TFT-shaped circuit configuration having a drive control source line and a gate line arranged vertically and horizontally, or a plurality of single-shaped electrodes arranged on one substrate side. The present invention can also be applied to any configuration of a simple matrix type having a configuration in which a plurality of single electrode electrodes are arranged on the other substrate side. Moreover, the liquid crystal cell 1 can apply any structure of a transmissive type, a reflective type, and a transflective type.

In the liquid crystal cell 1 of this embodiment, a plurality of wirings S of the liquid crystal driving circuit are formed in the display region of the liquid crystal cell 1, and the wirings S are formed so as to extend outward from the display region and the substrate Extension wiring to the elongate drive element connection region 7 drawn out on the upper surface side of the extended portion 2a of (2) and partitioned along the edge portion 3a of the substrate 3 in the extended portion 2a. (11) is densely arranged.

In the drive element connection region 7, the necessary number of extension wirings 11 are aligned to match the alignment pitch of the connection terminals such as bumps of the drive element 9. Since these extension wirings 11 are preferably formed by extending the circuit wirings for liquid crystal driving constituting a part of the liquid crystal cell 1 as they are, they are usually formed of a transparent conductive film such as ITO, but separate conductive films such as metal wirings. What formed on the board | substrate 2 may be sufficient.

Next, in the upper end of the extended part 2a of the board | substrate 2, the drive element connection area | region 7 in the outer edge part (end part on the opposite side to the board | substrate 3 side in the upper surface of the extended part 2a). FPC wiring region 8 of the same length and width as that of) is formed, and the FPC wiring region 8 has a pitch that matches the pitch of the wiring portion 25 described later formed on the flexible printed circuit board 10. The plurality of single-shaped connection wires 15 are arranged in parallel with each other. These connection wirings 15 are usually formed of a transparent conductive film such as ITO, similarly to the extension wiring 11, but a conductive film such as metal wiring is formed on the extended portion 2a of the substrate 2 separately. It may be one.

The ACF film 16 is mounted so as to span the plurality of extension wirings 11 arranged in the driving element connection region 7 and the plurality of connection wirings 15 arranged in the FPC wiring region 8. The plurality of connection terminals 9a on one side of the drive element 9 are electrically connected to the ACF film 16 on the drive element connection region 7, and on the ACF film 16 on the wiring region 8. The plurality of connection terminals 9b on the other side of the drive element 9 are electrically connected to a portion near the drive element connection region 7. The drive element 9 has a main body portion 9A having a chip shape and including functional elements such as a semiconductor inside, and a plurality of bumps and the like having a pitch of about 20 μm to 50 μm on one side and the other side of the bottom surface side thereof. Connection terminals 9a and 9b are formed to protrude.

These connection terminals 9a and 9b are formed in the size of about 1000-8000 micrometers ² size, about 9 micrometers-20 micrometers in height, and the distance of 8 micrometers-20 micrometers between terminals, for example. 10 to 100 are formed on one side of the main body portion 9A.

The said ACF film 16 is a structure by which the electrically conductive particle was disperse | distributed in the inside of the binder which consists of an epoxy resin or an acrylic resin.

Although an example of the conceptual structure of the ACF film 16 used by this form is shown in FIG. 3, the ACF film 16 of this form becomes a top and bottom two-layer structure which consists of a base layer 20 and the dispersion layer 21, The base layer 20 has a structure of only a binder of a resin in which the conductive particles are not dispersed, and in the dispersion layer 21 thereon, there are 1 million conductive particles 22 having a particle diameter of about 3 µm to 5 µm. It has the structure disperse | distributed and mixed in the binder 23 of resin at the density of about -7.5 million pieces / cc.

Since the fluidity | liquidity of a binder improves and it becomes easy to disperse | distribute electroconductive particle uniformly to a binder by setting it as two-layer structure as mentioned above, it is preferable.

For example, the ACF film 16 has a thickness of about 20 μm to 25 μm as a whole, and the thickness of the base layer 20 is about 9 μm to 15 μm, for example, and the dispersion layer 21 is, for example, 10. The thickness is about 14 µm to 14 µm.

If the ACF film 16 is too thick, the resin is too large and the contact resistance tends to rise. On the contrary, if the ACF film 16 is too thin, the resin is not sufficient and the binder is excessively flowed, so that the maintenance of the conductive particles becomes impossible. .

It is preferable that the resin binder which comprises the said ACF film 16 becomes an elasticity modulus, for example, about 1.0-3.0 GPa (at 30 degreeC), and 0.05 GPa or less (at 150 degreeC). Moreover, the range of 100-150 degreeC of the crystallization temperature (Tg) of a binder is preferable.

When the modulus of elasticity is lower than 1GPa at 30 ° C, the connection resistance is increased, and when larger than 3GPa, the adhesion of the ACF film 16 is lowered, which is not preferable. Moreover, when the crystallization temperature (Tg) of a binder is less than 100 degreeC, since the tendency to react by temporary fixation becomes strong, handling becomes difficult, and when Tg exceeds 150 degreeC, since reaction temperature becomes high, it crimps It is not preferable because the temperature must be increased and handling becomes difficult.

The said drive element 9 pressurizes the connection terminal 9a, 9b in the state heated with respect to the ACF film 16, and invades a some connection terminal 9a, 9b in the binder of the ACF film 16. FIG. The plurality of connection terminals 9a are electrically connected to the extension wiring 11 via the plurality of conductive particles 22, and the plurality of connection terminals 9b are connected to each other via the conductive particles 22. It is electrically connected to the wiring 15, and the binder is flow-solidified by subsequent heating, and it joins by crimping | bonding each connection terminal 9a, 9b to each wiring 11,15.

Next, on the wiring 15 in the outer side of the part in which the drive element 9 was joined in the extension part 2a of the said board | substrate 2, the ACF film 16 is the edge part of the board | substrate 2 as it is. It extends so that it may reach | attain and the wiring part 25 of the flexible printed circuit board 10 is joined by the ACF film 16 of the part.

In this flexible printed circuit board 10, the wiring part 25 which consists of copper foil, a plating layer, etc. in the base material layer which consists of polyimides is formed in predetermined pitch.

As a specific structure of these wiring part 25, the following laminated structure can be illustrated. For example, a lamination structure of an adhesive layer, a copper foil, a Th plating layer, a Ni plating layer, and an Au plating layer, a lamination structure of an adhesive layer, a copper foil, Th plating layer, and a lead or lead-free plating layer, and a lamination of an adhesive layer, copper foil, lead, or lead-free plating layer The structure, the laminated structure of a copper foil, Th layer, Ni plating layer, and Au plating layer, the laminated structure of a copper foil, lead, or lead-free plating layer, etc. can be illustrated.

In addition, in the flexible printed circuit board 10, the pitch of the wiring part 25 is about 0.06 mm-4 mm, the width (conductor terminal width) of the wiring part of the flexible printed circuit board edge part is about 0.03 mm-1 mm, and thickness is 10 micrometers. About 80 micrometers, the space between each conductor of the wiring part 25 is about 0.03 mm-2 mm.

As described above, the pitch, width, and height of the connection terminal 9b of the drive element 9 are in the order of several micrometers to several ten micrometers, and the pitch of the wiring portion 25 of the flexible printed circuit board 10 with respect to these pitches and widths. Since the width is in the range of about 0.1 mm to several mm, the size of each other is in different orders. Conventionally, connection of terminals and conductors with different orders such as these is difficult to obtain good compressibility in one ACF film. However, if the ACF film 16 having the above-described structure is used, in addition to the kind and thickness of a specific resin binder, good conductivity is achieved. Since the ACF film 16 which made the dispersion state of electroconductive particle into the appropriate range is used as a particle size, even if it is the connection terminal 9a, 9b and the wiring part 25 of a different size and pitch, one piece of ACF film It can be shared using (16), and either part can be crimp-bonded by favorable joining property.

For example, when the connection terminal of the conventional drive element 9 is a pitch and width of several 10 micrometers order, and the pitch and width of the wiring part of a flexible printed circuit board are about 0.1 mm-0.6 mm, respectively, the resin of an ACF film at the time of crimping | compression-bonding Since it melts with heat and flows and joins, the terminal and wiring part with different pitches and widths could not be crimped | bonded by the same ACF film, but even if both are shared and crimped | bonded by using the above-mentioned ACF film 16, good joint reliability, Strength can be realized.

In addition, since the base of the connection terminal 9b of the drive element 9 and the base of the wiring portion 25 of the flexible printed circuit board 10 are all made of the same ACF film 16, the connection terminal 9b and the wiring The pressure bonding of the part 25 can be performed by the same press head.

Although this state is shown in FIG. 4, by simultaneously pressurizing the drive element 9 and the flexible printed circuit board 10 using the pressurizing head 26 which has the adjacent pressurizing surfaces 26a and 26b via a step part, With one ACF film 16, the drive element 9 and the flexible printed circuit board 10 from which a pitch and a magnitude | size differ can be crimp-bonded simultaneously.

Thereby, since the connection terminal 9b of the drive element 9 and the wiring part 25 of the flexible printed circuit board 10 can be crimped | compression-bonded with the same pressurizing head 26 without a trouble even if possible, a drive element The crimping junction part of the connection terminal 9b of (9) and the crimping junction part of the wiring part 25 of the flexible printed circuit board 10 can be approached and arrange | positioned so far, for example, about 0.2 mm Since it can join by a space | gap, it has a characteristic which can provide the joining structure which there is no waste space without a gap in the extending part 2a of the board | substrate 2. As shown in FIG.

On the other hand, in the conventional structure, since the connection part of the connection terminal of the drive element 9 and the wiring part of the flexible printed circuit board were implemented by the structure which used each ACF film, when pressing each place by the pressure head and crimping | bonding, Although the clearance of about ± 0.3 mm is required as a minimum, only a portion of the clearance generates useless space, and furthermore, there is a problem that the area of the extended portion of the substrate 2 cannot be made small, but the structure of this embodiment By adopting the above, the extended portion 2a of the substrate 2 can be miniaturized more than ever. Therefore, the liquid crystal display device A of this aspect has a desirable feature in terms of space saving for use in small electronic devices such as mobile phones, which have been miniaturized.

For example, when each ACF film is used for the connection area for a drive element and the area | region for flexible printed circuit board connection conventionally, about 0.6 mm-several mm of the position control of the pressure head for crimping both, Although clearance was absolutely required, by using this type of structure and sharing the ACF film, it is possible to narrow the useless space up to a gap of about 0.2 mm. Accordingly, in the structure of the present embodiment, miniaturization of about 0.4 mm to several mm is possible, but since the liquid crystal display device is required to be miniaturized even if only 1 mm of moisture is required in the internal structure of the cellular phone, the effect is large.

Moreover, since the ACF film which used two types conventionally can be unified by one type, common use of an ACF film becomes possible, and it becomes possible to reduce the required cost of an ACF film to about 1/2. In addition, if two types of ACF films are stored as in the prior art, since the binder is cured with time depending on the type of binder resin, storage and maintenance of the ACF film are complicated, and two types of ACFs are depending on the type of binder resin. Although the storage period of the film had to be managed, since the ACF film can be unified into one type, the storage itself of the ACF film becomes easy and contributes to the simplification of the manufacturing process of the structure using the ACF film 16.

Moreover, although the embodiment which applied this invention to the connection part of the drive element 9, such as the drive IC of a liquid crystal display device, and the flexible printed circuit board 10 in the past embodiment was demonstrated, the structure of this invention is limited to this. It can be applied widely when joining an element having a plurality of connection terminals and a wiring portion of a flexible printed circuit board on a substrate, and in particular, the size and pitch of the connection terminal on the element side and the size and pitch of the wiring portion of the flexible printed circuit board. It goes without saying that the present invention can be widely applied to the general connection structure in other cases.

Example

1st wiring group with respect to the 2nd wiring group of the width 27micrometer and the pitch 42micrometer which consist of ITO formed on the glass substrate, and the width 0.08mm and pitch 0.16mm which consist of ITO formed on the glass substrate edge part. And an ACF film having a thickness of 24 µm was disposed so as to span the second wiring group.

A liquid crystal drive IC having 808 metal pads having a height of 15 μm, such as 27 μm in width and 42 μm in pitch, was provided on the ACF film on the first wiring group, and 0.08 mm in width on the ACF film on the second wiring group. And the flexible printed circuit board provided with the wiring part of pitch 0.16 mm were pressed, the press head was pressed by the pressing force of 10 MPa from both tops, and it heated and joined at 200 degreeC, and was bonded. This pressurizing head has a structure having a step on the pressing surface, and employs a structure capable of heating while pressing the liquid crystal driving IC and the flexible printed circuit board at the same pressing force.

Here, the edge part of liquid crystal drive IC and the edge part of a flexible printed circuit board were joined as the clearance gap of 0.2 mm.

The ACF film used here has a total thickness of 24 mu m of epoxy resin, a base layer thickness of 12 mu m in a portion without conductive particles, a thickness of 12 mu m of a dispersed dispersion layer portion of conductive particles, and a diameter of 4 mu m of conductive particles of 3.1 million pieces / What was dispersed at the density of ㎣ was used. The elasticity modulus of the binder made of epoxy resin was 2.6 GPa (30 degreeC).

Although the driving IC and the flexible printed circuit board were bonded to the wiring group by 50, and the driving IC was subjected to a high temperature and high humidity energization test through the wiring portion of the flexible printed circuit board, the total number operates as usual without generating a bonding failure. It was.

Therefore, it was proved by the said wiring connection structure that joining of the connection terminal of a drive IC and the wiring part of a flexible printed circuit board is possible with one ACF film.

Next, although the ACF film which made the layer thickness of an ACF film 35 micrometers was manufactured, and it provided for the test mentioned above, display quality fell slightly by the fall of the conduction function of a connection terminal.

This is thought to be that the ACF film becomes thick, and the conductive particles could not touch some wiring in the above-mentioned pressure bonding.

Although the ACF film which made the layer thickness of an ACF film 15 micrometers was manufactured, and it provided for the test mentioned above, display quality fell slightly by the fall of the conduction function of a connection terminal. It is thought that this is because the ACF film is thin, the binder portion flows in the pressure bonding described above, and the holding by the binder of the conductive particles is reduced.

A test for joining 50 driving ICs in the same manner as above using a layer thickness of an ACF film having a thickness of 22 µm, an average conductive particle diameter of 4 µm, and a conductive particle density of 2 million / dl, in which a binder has a different elastic modulus. As a result of conducting and conducting a power test, the display quality was slightly lowered in the binder having an elasticity modulus of 0.5 GPa and the binder of 3.3 GPa due to the decrease in the power supply function.

On the other hand, the connection failure did not generate | occur | produce in the sample using the binder resin of 1.0 G ', the sample using the binder resin of 2.0 G', and the sample using the binder resin of 3.0 G '. This is assumed to be due to the following reasons.

It is thought that the sample whose elasticity modulus is 0.5 GPa is good in the fluidity | liquidity of a binder, and the adhesiveness of an ACF film fell. In addition, it is thought that the conduction function between terminals was reduced by the aggregation of electroconductive particle in the sample whose elasticity modulus is 3.0 GPa.

As the layer thickness of the ACF film was 22 μm and the conductive particle density was 2 million / dl, the same bonding test was conducted using a different conductive particle diameter to be used. In the sample used and the sample using the electroconductive particle of average 6 micrometers, display quality fell slightly by the fall of conduction function.

On the other hand, the connection failure did not generate | occur | produce in the sample using the electroconductive particle of average 3 micrometer diameter, and the sample using the electroconductive particle of average 5 micrometer.

This is assumed to be due to the following reasons. When the conductive particles are 2 µm, the function of absorbing the difference in the bump height of the drive element (drive IC) is considered to be reduced, and the conduction function is deteriorated. Moreover, when the electroconductive particle is 6 micrometers, it is thought that the conduction function of the electroconductive particle fell between the bumps of a drive IC.

From the above test results, when the binder consists of an epoxy resin or an acrylic resin, and the binder thickness is 20-25 micrometers, it turned out that the range whose elasticity modulus of the said binder is 1.0-3.0 GPa is preferable.

Moreover, when the said binder consists of an epoxy resin or an acrylic resin, and the said binder thickness is 20-25 micrometers, it turned out that the range whose diameter of the electroconductive particle disperse | distributed to the said binder is 3 micrometers-5 micrometers is preferable.

Moreover, when the said binder consists of an epoxy resin or an acrylic resin, and the said binder thickness is 20-25 micrometers, it is preferable that the density | concentration of the electrically-conductive particle disperse | distributed to the said binder is 1 million / dl-7.5 million / dl It turned out.

Industrial availability

In the present invention, the present invention can be widely applied to a structure in which an element and a flexible printed circuit board are connected to other substrates. For example, the structure of the present invention is connected to a connection portion of a driving IC of a liquid crystal display and a flexible printed circuit board. Although it can apply, it is a matter of course that it is widely applicable to the connection wiring part of other general structures.

According to the present invention, the wiring connection directly under the element and the wiring connection directly under the FPC can be shared by one ACF, and by making one ACF film, the wiring structure can be compared with the conventional structure in which two ACF films are used. Simplification and common use are possible. Moreover, compared with the conventional structure which provided two ACF films and crimp-connected individually, by crimping | compressing one ACF film, the workability at the time of wiring connection can be improved, and when one ACF film is crimped | bonded, By providing conditions, the reliability of a connection can also be improved.

Moreover, compared with the case where each ACF film is arrange | positioned, since it does not need to press-compress under each condition at the time of heating and crimping | bonding, it becomes unnecessary to form the clearance required when crimping an ACF film, respectively. The element and the flexible printed circuit board can be placed in as close contact as possible. Furthermore, by employing the element and the flexible printed circuit board in the structure attached to the substrate of the liquid crystal display device, it contributes to the narrowing and softening of the board | substrate for liquid crystal display devices.

Claims (12)

The element connection area | region and FPC wiring area | region are formed on a board | substrate, ACF film of the structure which disperse | distributed electroconductive particle to the binder of resin was arrange | positioned over the said element connection area | region and said FPC wiring area | region, and the ACF on the said element connection area | region is arrange | positioned. An element having a connection terminal is provided on the film in a state in which the connection terminal is electrically connected to the wiring of the element connection region via an ACF film, and on the ACF film on the wiring region for FPC, the FPC film is A wiring connection structure is provided in a state in which a wiring portion is electrically connected to a connection wiring in the wiring region for an FPC via an ACF film. The method of claim 1, The pitch and thickness of the connection terminal part of the said element, and the pitch and thickness of the wiring part of the said FPC film become different values, The wiring connection structure characterized by the above-mentioned. The method of claim 1, The connection terminal of the said element is connected by thermocompression bonding with respect to the wiring of the element connection area | region on the said board | substrate through the electroconductive particle of the said ACF film, The wiring part of the said FPC film is connected to the FPC on the said board | substrate via the electroconductive particle of the said ACF film. A wiring connection structure, characterized in that it is connected by thermocompression bonding to a connection wiring in a wiring wiring region. The method of claim 1, Said binder consists of an epoxy resin or an acrylic resin, The said binder thickness is 20-25 micrometers, The elasticity modulus of the said binder becomes 1.0-3.0 GPa The wiring connection structure characterized by the above-mentioned. The method of claim 1, Said binder consists of an epoxy resin or an acrylic resin, The said binder thickness is 20-25 micrometers, The diameter of the electrically-conductive particle disperse | distributed to the said binder becomes 3 micrometers-5 micrometers, The wiring connection structure characterized by the above-mentioned. The method of claim 1, Wherein the binder is made of an epoxy resin or an acrylic resin, the binder thickness is 20 to 25㎛, the density of the conductive particles dispersed and blended in the binder ranges from 1 million / ㎣ to 7.5 million / 하는 Wiring connection structure. A liquid crystal display device comprising a pair of substrates facing each other with a liquid crystal layer interposed therebetween, wherein wirings are formed on the liquid crystal layer side surface of each substrate, wherein each of the wiring lines is connected to an element connection region of the one substrate. And an FPC wiring region is formed while being separated from the element connecting region at the edge of the substrate, and conductive particles are dispersed in a binder of resin over both regions in the element connecting region and the FPC wiring region. ACF film is arrange | positioned, On the ACF film on the said element connection area | region, the element provided with a connection terminal is arrange | positioned in the state connected with the connection terminal to the wiring of the said element connection area via an ACF film, and for the said FPC On the ACF film on the wiring area, the FPC film is connected to the wiring part of the wiring area for FPC via the ACF film. That is made up arrangement liquid crystal display device according to claim. The method of claim 7, wherein The pitch and thickness of the connection terminal part of the said element, and the pitch and thickness of the wiring part of the said FPC film become different values, The liquid crystal display device characterized by the above-mentioned. The method of claim 7, wherein The connection terminal of the said element is connected by thermocompression bonding with respect to the wiring of the element connection area | region on the said board | substrate through the electroconductive particle of the said ACF film, The wiring part of the said FPC film is connected to the FPC on the said board | substrate via the electroconductive particle of the said ACF film. A liquid crystal display device, wherein the liquid crystal display device is thermocompression-bonded with respect to the connection wiring of the wiring region for use. The method of claim 7, wherein The said binder consists of an epoxy resin or an acrylic resin, the said binder thickness is 20-25 micrometers, and the elasticity modulus of the said binder becomes 1.0-3.0 GPa The liquid crystal display device characterized by the above-mentioned. The method of claim 7, wherein The binder is composed of an epoxy resin or an acrylic resin, the binder thickness is 20 to 25 µm, and the diameter of the conductive particles dispersed and blended in the binder is in the range of 3 µm to 5 µm. The method of claim 7, wherein Wherein the binder is made of an epoxy resin or an acrylic resin, the binder thickness is 20 to 25㎛, the density of the conductive particles dispersed and blended in the binder ranges from 1 million / ㎣ to 7.5 million / 하는 Liquid crystal display.

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