JPH112830A - Liquid crystal device and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve connection reliability by constituting an anisotropic conductive adhesion(ACF) film by mixing and dispersing particles of grain size larger than the basic grain size of conductive particles and particles of smaller grain size of a conductive material in the ACF in addition to the conductive particles of the basic grain size. SOLUTION: In the ACF, resin balls 8 of 10 μm coated with gold alloy are dispersed uniformly as the basic conductive particles of the center diameter. Further, the balls 9 of resin of the same kind of 16 μm are mixed by 5% of the dispersion amount of the basic conductive particles. Further, resin balls of 4 μm are mixed by 40% of the dispersion amount of the basic conductive particles. The ACF 5 which has three kinds of particle contained and mixed is temporarily pressed against to the electrode 7 of a flexible substrate(COF) 6, positioned, and further aligned, and compression bonding is carried out at a specific heating temperature. The conductive particles 8 to 10 are crushed to connect the electrode terminal 2 formed on a liquid crystal panel to the electrode terminal 7 of the COF 6, securing electric continuity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal device in which electrode terminals provided on a liquid crystal panel are connected to electrode terminals provided on a flexible substrate on which a driving IC is mounted.

[0002]

2. Description of the Related Art Among thin flat display devices, a flat display device using a liquid crystal has been developed for a wide range of applications from ultra-small micro size to ultra-large HDTV with recent diversification of industrial equipment. ing. Further, these flat display devices are used as displays for television receivers, OA equipment and transmission equipment, or as display devices for video equipment and entertainment equipment. In particular, in order to use it as a display device for video equipment, it is necessary to meet various needs such as realization of a high-resolution liquid crystal device, realization of steepness, realization of higher quality and higher image quality.

In order to satisfy these demands, continuous research and development have been carried out in various fields, various display methods and methods have been proposed, and efforts have been made day and night to respond to cost reduction in the market. I have.

For example, in order to configure a high-resolution liquid crystal display device, the number of signal lines in the liquid crystal display device is increased,
By increasing the number of pixels, a high-resolution liquid crystal display device is realized.

However, as the number of pixels increases and the number of signal lines further increases, the signal lines arranged on the liquid crystal panel and electrode terminals become finer and the signal lines in the device become lower. Resistance is also indispensable, and metallization of signal lines and electrode terminals and complication of the structure are inevitable.

[0006] As such an electrode structure, for example, for a chromium and ITO coated electrode with a terminal pitch of 100 microns as a fine structure, a configuration of a protective passivation film at the end has been proposed as a known technique.

A description will be given below with reference to FIGS. FIG. 14 is a cross-sectional view showing a conventional method of connecting a liquid crystal panel. FIG. 15 is a cross-sectional view for explaining a method of connecting the anisotropic conductive adhesive film in FIG.
FIG. 6 is a diagram showing a configuration in which connection in FIG. 14 is completed.

Conventionally, an electrode terminal 12 arranged on a glass substrate 11 shown in FIG.
Because the electrode pitch is wide and the flatness is good,
The flexible substrate 14 (hereinafter referred to as COF) on which the driving IC 13 is mounted is attached to the outer lead bonding (hereinafter referred to as O).
The anisotropic conductive adhesive film 15 (hereinafter referred to as ACF) used to connect to the glass substrate 11 by LB) is crushed by a thermocompression bonding machine, the connection area is sufficiently secured, and the connection resistance is not regarded as a problem. .

However, as the number of electrode terminals increases with an increase in the number of pixels, and as the terminal widths become finer, short-circuiting between terminals and an increase in connection resistance are cited as problems. As shown in FIG. 17, the electrodes arranged on the glass substrate are metallized with the electrode terminals 2, ITO 3 is added to supplement the adhesion, and a passivation film 4 is provided to prevent a short circuit in the horizontal direction. This has complicated the electrode structure. Also, ACF
The conductive particles interposed therein were made finer and the particle size was made uniform.

[0010]

However, in the connection portion of the electrode terminal in which the miniaturization of the electrode terminal and the complicated structure are advanced as in the prior art, the connection reliability is lowered. Had.

Accordingly, an object of the present invention is to provide a liquid crystal device with improved connection reliability between electrode terminals.

[0012]

According to a first aspect of the present invention, there is provided a liquid crystal device having a liquid crystal panel and a substrate on which a driving IC for driving the liquid crystal panel is mounted. The formed first electrode terminal and the second electrode terminal formed on the flexible substrate on which the driving IC is mounted are connected by an anisotropic conductive adhesive film. At least the first conductive particles and the second conductive particles having different particle diameters from the first conductive particles are mixed.

With such a configuration, the electrode terminals can be reliably connected to each other, and even when the electrode terminals have a narrow pitch between the electrodes, both electrode terminals can be reliably connected. It becomes possible.

According to a second aspect of the present invention, in the anisotropic conductive adhesive film, a plurality of particles having a different particle size from the first conductive particles are mixed, and the plurality of particles are the first conductive particles. Characterized by having a particle size of ± 5% to 60% with respect to the particle size of the conductive particles. By dispersing the particle size in such a range, even a liquid crystal panel having a configuration in which the electrode pitch is narrow can be easily connected.

According to a third aspect of the present invention, the plurality of particles are increased in a ratio of 5% to 40% with respect to the first conductive particles and dispersed in the anisotropic conductive adhesive film. It is characterized by the following. The electrode terminals can be reliably connected to each other by dispersing a different material in the illegal conductive adhesive and increasing the amount by 5 to 40% with respect to the first conductive particles.

The invention according to claim 4 is characterized in that the plurality of particles are formed of a material different from the first conductive particles. The invention according to claim 5 further includes:
The particles in the anisotropic conductive adhesive film are composed of styrene balls plated with nickel, a gold alloy or the like on the surface, or nickel particles, and carbon particles. It is characterized by being mixed in the conductive adhesive film.

The invention according to claim 6 is a liquid crystal for connecting a first electrode terminal formed on the liquid crystal panel and a second electrode terminal formed on a flexible substrate by the anisotropic conductive adhesive film. The method for manufacturing an apparatus includes a step of temporarily pressing the first electrode terminal and the second electrode terminal by ultrasonic waves and a step of pressing the first electrode terminal and the second electrode terminal. And By adopting such a manufacturing method, large particles trapped in a narrow portion between terminals by an ultrasonic wave (hereinafter, referred to as USC) at the time of OLB temporary pressing by a pressing machine to a wide gap portion. Alternatively, a connection with flatness can be obtained by moving the terminal to the outside. In addition, a reliable liquid crystal device can be supplied by reliable connection.

[0018]

Embodiments of the present invention will be described below.

In the anisotropic conductive adhesive film (ACF), in addition to the particles having the basic particle size of the conductive material particles, a conductive material having a particle size larger and smaller than the basic particle size is mixed and dispersed. Configure ACF. By placing this ACF between the two electrode terminals and crimping it, the conductive material enters without gap between the terminals having the narrow portion and the wide portion, so that the connection reliability is improved.

Further, by using an ACF in which conductive particles having large and small variations are mixed and dispersed in addition to the basic particles obtained by plating nickel and gold on a styrene ball, it is possible to take advantage of the characteristics of each other.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a diagram showing a main part of a first embodiment of the liquid crystal device according to the first aspect of the present invention. In FIG. 1, 1 is a glass substrate, 2 is a chromium electrode terminal, 3 is ITO, 4 is a passivation film, 5 is ACF,
6 is a flexible substrate, 7 is an electrode terminal, 8, 9, 10,
Is a conductive particle, and FIG. 2 is a diagram showing the connection completion of FIG.
FIG. 3 is a top view of FIG.

First, the configuration will be described. The surface of 240 terminals having a finger width of 50 μm and a space width of 50 μm and having a pitch of 100 μm and having a pitch of 50 μm arranged on the glass substrate 1 is kept clean. The resin balls 8 were uniformly dispersed to obtain central diameter particles. In addition, together with the basic conductive particles, a resin ball 9 of the same type of 16 microns is used.
Is 5 with respect to the dispersion amount of the basic conductive particles of a 10 micron ball.
% Mixed. In addition, 4 micron resin balls 10
40 with respect to the dispersion amount of the basic conductive particles of the 0 micron ball.
%. Containing these three types of particles,
The mixed ACF5 was preliminarily pressure-bonded to the electrode 7 of COF6, alignment was performed, alignment was further performed, and pressure-bonding was performed at a predetermined heating temperature of 270 ° C. for 20 seconds. Then, by crushing the conductive particles 8, 9, and 10, the electrode terminals 2 formed on the liquid crystal panel were connected to the electrode terminals 7 of the COF, thereby ensuring conduction.

The conductive particle diameter used in Example 1 is 16 microns on the large diameter side, which is 60% of the basic particle diameter. On the other hand, the diameter is 4 μm on the small diameter side, which is 40% of the particle diameter of the basic particles.

When the particle diameter is further increased, the crushing amount of the particles in the OLB connection is too large, so that the occupied area after the crushing becomes excessive and the protrusion from the electrode terminal increases. Therefore, in a narrow pitch connection, a short circuit or a leak with an adjacent terminal may occur.

Further, when the particle diameter is further reduced, the initial purpose is lost because it is difficult to secure a connection area due to an excessively small crushing amount.

Further, when the content is less than 5%, the dispersion is out of the range of the dispersion limit, and when it exceeds 40%, the total dispersion becomes excessive, so that the amount of residence in the space existing between the electrode terminals is excessive. The leakage between the particles and further between the electrode terminals becomes a surface.

According to the above-described structure, the conductive particles having a basic particle diameter of 10 μm and the conductive particles having different particle diameters of 16 μm and 4 μm interposed in the ACF are crushed between the electrode terminals. So the connection area is large,
In addition, the connection resistance can be reduced and reliable conduction can be maintained.

(Embodiment 2) FIG. 4 is a view showing a main part of a second embodiment of the liquid crystal device according to the second and third aspects of the present invention. FIG. 5 is a diagram showing the connection completion of FIG. FIG. 6 is a top view of FIG.

Electrode terminals 2 are provided at a 120-micron pitch from a wiring pattern made of ITO drawn out of the element substrate, and the electrode terminal portions (also simply referred to as electrode portions) are provided.
A liquid crystal cell was composed of a glass substrate 1 formed of aluminum metal 3 at a thickness of 1200 ° and an opposite substrate. Then, in the ACF5 in which resin balls having a center particle diameter of 10 microns and gold plating is dispersed on the surface, conductive particles of 15 μm, which is increased by 30% with respect to the dispersion amount of the 10 μm particles, and similarly, the 10 μm particles 2 for the amount of dispersion
The conductive particles of 6 μm having different diameters increased by 0% were mixed and dispersed. The surfaces of these different-diameter conductive particles are coated with a metal such as nickel or aluminum.

As described above, using the ACF formed by mixing three kinds of conductive particles, a temporary compression bonding is performed on the mounting area of the electrode terminals 7 of the COF 6 having a pattern of 120 μm and having a length of 2 mm. Was.

Next, while keeping the liquid crystal cell clean,
The electrode terminal 2 of the liquid crystal cell was aligned with the electrode terminal 7 of the COF, the alignment error was kept within 1 micron, and then the substrate was crimped for 20 seconds using a crimping machine while keeping the tool temperature at 250 ° C. The final pressure gap at this time was 2 microns. The ACF used at this time was a thermosetting resin.

According to the above-described structure, the connection portion of each electrode terminal is compressed by applying pressure so that conductive particles having a size of 15 μm are embedded in the aluminum metal in addition to the normal collapse. Connection and high reliability was obtained.

(Embodiment 3) FIG. 7 is a view showing a main part of a third embodiment of the liquid crystal device according to the present invention. FIG. 8 is a diagram showing the connection completion of FIG. FIG. 9 is a top view of FIG.

The glass substrate 1 is patterned by a patterning process.
A chromium electrode terminal 2 having a thickness of 200 mm and a width of 45 microns is provided, and a 300 mm thick ITO3 is provided on both sides of the terminal so as to supplement the adhesion of chrome to the glass.
A group of terminals having a pitch of 0 micron was formed. Further, in order to prevent signal leakage and short circuit due to the fine pitch, a part of the passivation layer 4 is configured to wrap a part of each terminal.

ACF5 was preliminarily pressure-bonded to COF6, which was patterned and formed to face the terminal portion. The conductive material interposed in the ACF used at this time was a styrene resin ball having a center particle diameter of 10 μm and a gold plating on the surface.

Further, nickel metal particles having different diameters of 13 μm and 5 μm were respectively increased in proportions of 15% and 10% with respect to the dispersion amount of the center diameter particles, and these were mixed and dispersed. Subsequently, the electrode terminals 2 on the glass substrate 1 and C
The electrode terminal 7 of the OF 6 was aligned and temporarily press-bonded. Furthermore, it crimped for 20 seconds using the tool of 250 degreeC of heating temperature.

With the above-described configuration, a liquid crystal device having a low resistance can be supplied due to the elasticity of the styrene resin and the hardness of the nickel metal for the crimp-connected terminals.

(Embodiment 4) A fourth embodiment will be described with reference to FIGS.

The glass substrate 1 is patterned by a patterning process.
A chromium electrode 2 having a thickness of 800 mm and a width of 60 μm is provided, and ITO 3 is coated with 400 mm around the terminal electrode.
It was arranged at the thickness of. Also, the terminal pitch of the flexible substrate 6 wired to mount the driving IC was set to 120 μm so as to face the terminal electrode on the glass substrate.

ACF5 was temporarily bonded to the COF6.
The conductive material dispersed in the ACF 5 used at this time was a styrene ball having a center particle diameter of 10 μm and having a surface plated with nickel or / and an alloy of gold and nickel. In addition, different diameters of 8 microns and 14
Micron carbon was mixed and dispersed by increasing the dispersion amount of each by 30% of the dispersion amount of the styrene ball.

Subsequently, the electrode terminal 2 on the glass substrate 1 and CO
The electrode terminal 7 of F6 was aligned and pre-bonded. Further, pressure bonding was performed for 25 seconds using a tool having a heating temperature of 270 ° C.

The electrode terminals crimped and connected by the above-described structure can provide a liquid crystal device in a connected state with low resistance and excellent flatness due to the elasticity of styrene resin and the hardness of nickel metal. .

(Embodiment 5) FIG. 10 is a view showing a main part of a fifth embodiment of the liquid crystal device. FIG. 11 is a diagram showing a temporary pressure bonding state in FIG. FIG. 12 is a diagram showing the connection completion of FIG. FIG. 13 is a top view of FIG.

I drawn from the element substrate of the liquid crystal panel
The electrode terminal 2 continuing from the wiring pattern by TO has a terminal width of 5
0 micron, space 50 micron, 100
It was formed to a thickness of 1600 ° by chromium metal at a micron pitch. Furthermore, in order to improve and supplement the adhesion between the glass substrate 1 and the metal chromium, ITO3 is applied around the terminals at 400 mm.
It was arranged at the thickness of. Further, the insulating layer 4 is disposed outside the ITO layer 3 in order to prevent signal leakage and short circuit due to a narrow pitch.

Further, a COF was produced by performing a correction process with the terminal pitch of the flexible substrate 6 wired for mounting the driving IC set to 100 μm.

ACF5 in which particles of different diameters were mixed and dispersed in the COF6 was temporarily compressed. ACF5 used at this time
The conductive material obtained by applying gold plating to a styrene resin 5 micron ball is used as the central diameter particles, and the styrene resin 7 micron and 3 micron balls are increased by 20% with respect to the central diameter particles to the different diameter particles, respectively. The mixture was mixed and dispersed with an amount increased by 15%.

Next, the electrode terminals 2 on the glass substrate 1 were kept clean, and the electrode terminals 7 of the COF 6 were aligned and preliminarily pressed. At the time of temporary compression bonding, the ultrasonic waves 11 are oscillated using a USC oscillator, and the large-diameter particles sandwiched between the narrow gaps between the electrode terminals are moved out of the wide gaps or out of the terminals by using the vibration caused by the oscillation waves. The gap was moved to ensure the flatness of the gap. Subsequently, compression bonding was performed for 20 seconds at a bonding tool temperature of 265 ° C. using a thermocompression bonding machine.

According to the above configuration, it is possible to supply a liquid crystal device which is excellent in flatness in pressure bonding and has high long-term reliability.

[0050]

According to the present invention having the above-described structure, the electrode terminals can be reliably connected to each other.

[Brief description of the drawings]

FIG. 1 is a main cross-sectional view showing a first embodiment of the present invention.

FIG. 2 is a diagram showing connection completion in FIG. 1;

FIG. 3 is a top view of FIG. 2;

FIG. 4 is a main sectional view showing a second embodiment of the present invention.

FIG. 5 is a diagram showing connection completion in FIG. 4;

FIG. 6 is a top view of FIG. 5;

FIG. 7 is a main sectional view showing third and fourth embodiments of the present invention.

FIG. 8 is a diagram showing the connection completion in FIG. 7;

9 is a top view of FIG.

FIG. 10 is a main sectional view showing a fifth embodiment of the present invention.

FIG. 11 is a diagram showing a provisional pressure bonding state in FIG. 10;

FIG. 12 is a diagram showing the connection completion in FIG. 11;

FIG. 13 is a top view of FIG. 12;

FIG. 14 is a cross-sectional view illustrating a conventional liquid crystal panel connection method.

FIG. 15 is a sectional view for explaining a method of connecting the anisotropic conductive adhesive film in FIG. 14;

FIG. 16 is a diagram showing the connection completion in FIG. 14;

FIG. 17 is a complicated terminal structure diagram.

[Explanation of symbols]

 1. Glass substrate 2. 2. Electrode terminal ITO 4. Passivation 5. 5. Anisotropic conductive adhesive film (ACF) 6. Flexible board (COF) Electrode terminal 8. Conductive particles 9. Conductive particles 10. Conductive particles 11. Glass substrate 12. ITO wiring terminal 13. Drive IC 14. Flexible substrate 15. Anisotropic conductive adhesive film (ACF) 21. Ultrasound 22. Pressing force

Claims (6)

[Claims] 1. A liquid crystal device having a liquid crystal panel and a substrate on which a driving IC for driving the liquid crystal panel is mounted, a first electrode terminal formed on one substrate of the liquid crystal panel, A second electrode terminal formed on a flexible substrate on which an IC is mounted is connected by an anisotropic conductive adhesive film, wherein the anisotropic conductive adhesive film has at least a first conductive particle and the first conductive particle. A liquid crystal device comprising a mixture of particles and second conductive particles having different particle diameters. 2. The method according to claim 1, wherein a plurality of particles having a particle size different from that of the first conductive particles are mixed in the anisotropic conductive adhesive film, and the plurality of particles have a particle size of the first conductive particles. 2. The liquid crystal device according to claim 1, wherein the liquid crystal device has a particle size of ± 5% to 60% with respect to. 3. The method according to claim 1, wherein the plurality of particles are increased in an amount of 5% to 40% with respect to the first conductive particles and dispersed in the anisotropic conductive adhesive film. Item 1
The liquid crystal device according to the above. 4. The liquid crystal device according to claim 1, wherein the plurality of particles are formed of a material different from the first conductive particles. 5. The particles in the anisotropic conductive adhesive film are composed of styrene balls plated on the surface with nickel, a gold alloy or the like, or nickel particles or carbon particles, and conductive particles formed of different materials. 2. The liquid crystal device according to claim 1, wherein said liquid crystal is mixed in said anisotropic conductive adhesive film. 6. A method of manufacturing a liquid crystal device, wherein a first electrode terminal formed on the liquid crystal panel and a second electrode terminal formed on a flexible substrate are connected by the anisotropic conductive adhesive film. A step of temporarily crimping the first electrode terminal and the second electrode terminal by ultrasonic waves;
Pressurizing the electrode terminals of the liquid crystal device.