JPH07234411A - Liquid crystal display device and its production - Google Patents

Abstract

PURPOSE:To prevent the warpage of both base films stuck to each other at the time of producing plural pieces of liquid crystal display devices by cutting two pieces of the long-sized base films stuck to each other. CONSTITUTION:Slits 21 for preventing lancing the parts provided with a connecting terminal 16 of the rear side base film 1 are formed only on the front side base film 2. A difference, therefore, arises between the coeffts. of thermal expansion of both base films 1 and 2 but the warpage of both base films 1, 2 stuck to each other via a sealing material 12 is prevented if a material consisting of a material with which the curing reaction progresses at ordinary temp., for example, a two-part type epoxy liquid, is used as the sealing material 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device and a method for manufacturing the same.

[0002]

2. Description of the Related Art In a liquid crystal display device, two film substrates each having transparent electrodes formed on opposite surfaces thereof are bonded to each other via a sealing material, and a liquid crystal is placed between both film substrates inside the sealing material. There is an intervening structure. Further, in such a liquid crystal display device, there is a liquid crystal display device in which an end portion of one film substrate is projected from the other film substrate and a connection terminal is provided on the projected portion in order to achieve electrical connection to the outside. .

By the way, as one of the methods for manufacturing such a liquid crystal display device, two long or relatively large sheet-shaped base films for forming a plurality of film substrates are prepared and are transparent. After a predetermined pre-process such as an electrode forming process and a sealing material forming process, the two base films are attached to each other, and the two attached base films are attached by a cutter or the like before or after the liquid crystal injecting process. There is a method of manufacturing a plurality of liquid crystal display devices by cutting them.

However, in the conventional method of manufacturing such a liquid crystal display device, only one of the two bonded base films needs to be cut by a cutter or the like, but this cutting operation is very difficult. There was a problem. That is, of the two film substrates of the liquid crystal display device as the final product, one film substrate has an end protruding from the other film substrate, and the connecting terminal is provided on this protruding portion. The cut points of the base film of No. 1 do not coincide with each other. Moreover, the base film is formed of a thin film made of a resin such as polyethylene terephthalate (PET) or polyether sulfone (PES), and since sufficient processing accuracy cannot be obtained in cutting work,
It is very difficult to cut only one of the two bonded base films. As a result, when cutting only one of the two base films pasted together, make a cut in the part of the other base film where the connection terminals are provided, and scratch or completely cut the connection terminals in the same part. However, there is a problem that it is one of the factors that reduce the yield.

Therefore, recently, there has been considered a method of manufacturing a liquid crystal display device capable of preventing a cut from being formed in a portion provided with a connection terminal. In this manufacturing method, first, a rear-side base film for forming one or more rear-side film substrates and a front-side base film for forming the other, or front-side film substrates are prepared. On the upper surface of the rear side base film, a plurality of sealing materials made of thermosetting resin such as epoxy resin are formed by printing, and a plurality of sets of connection terminals are provided. On the other hand, slits are formed by punching in the portions of the front side base film corresponding to the portions of the rear side base film where the plurality of sets of connection terminals are provided, respectively.

After preparing the rear side base film and the front side base film as described above, in a state where the portion of the rear side base film where the connection terminals are provided is exposed through the slit of the front side base film. , The rear side base film and the front side base film are overlapped with each other with a sealing material. Next, the sealing material is cured by heating the both base films thus laminated with pressure applied from above and below, thereby bonding the rear side base film and the front side base film. Next, by cutting the bonded base films along a predetermined edge of the slit with a cutter or the like, the bonded base films are cut while avoiding the connection terminal exposed through the slit, and the connection is completed. The portion provided with the terminal is projected by an amount corresponding to the width of the slit. Therefore, it is possible to prevent the notch from entering the portion provided with the connection terminal, without damaging or completely cutting the connection terminal of the same portion,
The yield can be improved. Thus, the end of the rear film substrate is projected from the front film substrate,
A plurality of cells constituting the liquid crystal display device, in which the connection terminals are provided on the protruding portions, can be obtained.

[0007]

However, in the conventional method for manufacturing such a liquid crystal display device, since the slits are formed only in the front side base film, the coefficient of thermal expansion of both base films depends on the presence or absence of the slits. Different from each other, the coefficient of thermal expansion of the front side base film having slits becomes smaller than the coefficient of thermal expansion of the rear side base film having no slits. As a result, when both base films are overlapped with each other via the sealing material and then heated to cure the sealing material and bond the both base films, the bonded both base films warp. That is, by heating, the sealing material first flows and the rear side base film thermally expands more than the front side base film, and then the sealing material hardens, so that both base films return to their original state by subsequent cooling. However, the difference in thermal expansion between the base films remains almost as it is, and as a result, the bonded base films are warped. In such a case, there is a problem that not only the subsequent process is adversely affected, but also the gap between the two film substrates of the liquid crystal display device as the final product becomes non-uniform, and the display quality deteriorates. An object of the present invention is to provide a liquid crystal display device and a method for manufacturing the same, which can prevent both substrates which are bonded together from warping.

[0008]

The invention according to claim 1 is
The two substrates are bonded together via a sealing material made of a material that undergoes a curing reaction at room temperature. According to a fourth aspect of the present invention, the two film substrates are attached to each other, and at least one of the two film substrates has an end portion projected from the other film substrate,
When manufacturing a liquid crystal display device provided with a connection terminal in this protruding portion, one of the base film for forming a plurality of the one film substrate, and the other for forming a plurality of the other film substrate A base film is prepared, a plurality of sets of connection terminals corresponding to the connection terminals of the one film substrate are provided on the one base film, and a plurality of sets of connection terminals of the one base film of the other base film, respectively. A slit is formed in the corresponding portion, and the one base film and the other base film are bonded together via a sealing material made of a material that undergoes a curing reaction at room temperature, and then both the bonded base films are bonded together. A plurality of the liquid crystal display devices are manufactured by cutting the liquid crystal display device so as to come into contact with the slits.

[0009]

According to the present invention, since the sealing material is made of a material that undergoes a curing reaction at room temperature, when the two substrates are bonded together, the sealing material is first gelled at room temperature so that the fluidity disappears. When the sealing material is fully cured by heating until the two substrates return to their original state by subsequent cooling, the difference in thermal expansion between the two substrates almost disappears, so that the two substrates bonded together You can avoid warping.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, one embodiment of the present invention will be described with reference to FIGS. 1 to 3 by projecting one end of a rear film substrate from the other front film substrate, A case of manufacturing a liquid crystal display device in which a connecting terminal is provided on the protruding portion will be described. First, a rear side base film 1 as shown in FIG. 1 for forming a plurality of rear side film substrates and a front side base film 2 as shown in FIG. 2 for forming a plurality of front side film substrates are formed. prepare. Base films 1 and 2 are P
It is formed in a long shape (or a relatively large sheet shape) by a thin film made of a resin such as ET or PES, and sprocket holes 3 and 4 are formed at both widthwise ends thereof.

The remaining portion of the rear side base film 1 except the widthwise both end portions and the portions corresponding to every other sprocket holes 3 in the longitudinal direction is the film substrate forming region 1.
It is 1. On the upper surface of the film substrate forming area 11, a total of 18 sealing materials 12 are formed by printing, six in the width direction of the rear side base film 1 and three in the longitudinal direction. In this case, the sealant 12 is made of a material that undergoes a curing reaction at room temperature, that is, a material that has a reduced amount of a catalyst (curing agent) that cures at high temperature or a catalyst that cures at room temperature is added. It is made of thermosetting resin such as liquid epoxy resin. A liquid crystal inlet 13 is provided on the left side of the sealing material 12 in FIG. Before forming the sealing material 12, a transparent electrode 14 for the rear side made of ITO or the like is patterned on the upper surface of the film substrate forming region 11 as shown in FIG. 3B.
An alignment film 15 is formed on the upper surface thereof and a predetermined alignment treatment is performed. A connection terminal 16 is patterned on the upper surface of the film substrate formation region 11 in the right side portion (upper side portion in FIG. 1) of the sealing material 12 in FIG. 3B.

On the other hand, at predetermined 6 positions in the width direction of the front side base film 2, that is, at the portions corresponding to the portions of the rear side base film 1 where the connection terminals 16 are provided, the slits 21 are provided with the slits 21 on the rear side base film. Film 1
The film substrate forming region 11 is formed so as to extend over the entire length of the film substrate forming region 11. Before or after forming the slit 21, a transparent electrode 22 for the front side made of ITO or the like is patterned on the lower surface of the front side base film 2 as shown in FIG. 3B. An alignment film 23 is formed on the lower surface and a predetermined alignment treatment is performed. Further, a cloth material (not shown) for electrically connecting the front side base film 2 and the rear side base film 1 is formed by printing on each predetermined portion of the lower surface of the front side base film 2. .

After preparing the rear side base film 1 and the front side base film 2 as described above, a spacer (not shown) is sprayed inside the sealing material 12 of the rear side base film 1 if necessary. And so on. Next, as shown in FIGS. 3 (A) and 3 (B), the rear side base film 1 is exposed through the slit 21 and the portion of the rear side base film 1 where the connection terminals 16 are provided is exposed. The side base film 1 and the front side base film 2 are overlapped with each other with the sealing material 12 interposed therebetween. Next, pressure is applied from the upper and lower sides of the laminated base films 1 and 2 at room temperature of about 20 to 30 ° C. for about 40 to 60 hours or at room temperature of about 40 to 60 ° C. for about 10 to 20 hours. put. Then, the sealing material 12
Hardens to the point that it gels and loses fluidity. In this state, since it is a normal temperature treatment, both base films 1,
2 does not thermally expand. Next, when heat treatment is performed at a temperature of about 120 to 150 ° C. for about 2 to 5 hours, the sealing material 12 is fully cured. The heat treatment in this case may be performed in a pressurized state or may be performed in a state where the pressure is released. Then, in the state immediately after the heat treatment, both base films 1 and 2 are thermally expanded and a difference is caused in the thermal expansion, but the sealing material 12 gels before the heat treatment and loses fluidity, and thus flows. There is no such thing. After that, when cooling is performed by leaving it at room temperature, since the sealing material 12 does not flow during the heat treatment, both base films 1 and 2 return to their original state, and the difference in thermal expansion between the base films 1 and 2 is almost zero. Disappear. Therefore, it is possible to prevent both base films 1 and 2 attached via the sealing material 12 from warping, and it is possible to eliminate the inconvenience caused by the warpage of both base films 1 and 2.

Next, as shown by the alternate long and short dash line in FIG. 3 (A), the both base films 1 and 2 thus bonded are cut by a cutter or the like not shown. That is, the cutting of both base films 1 and 2 in the width direction is performed along the arrangement of the liquid crystal injection ports 13, and the cutting in the longitudinal direction is performed along the upper edge portion 21a of the slit 21 in FIG. When,
Avoid the connection terminal 16 exposed through the slit 21,
Both base films 1 and 2 bonded together have a slit 21.
Is cut so as to contact with, and the portion provided with the connection terminal 16 is projected by an amount corresponding to the width of the slit 21. Therefore, it is possible to prevent the notch from being formed in the portion where the connection terminal 16 is provided, and the connection terminal 16 in the portion can be prevented.
The yield can be improved without damaging or completely cutting. As a result, a plurality of cells constituting the liquid crystal display device are obtained, and the liquid crystal injection port 13 is exposed on the side surface. Then, a liquid crystal (not shown) is injected through the liquid crystal injection port 13, and then a resin (not shown) is applied to the liquid crystal injection port 13 and sealed. A liquid crystal display device is manufactured which is projected from the substrate and the connection terminals 16 are provided on the projected portion.

Now, a cloth material for electrically connecting the base films 1 and 2 will be described. As the material for the cloth material, a material obtained by mixing conductive particles with a thermosetting adhesive that is hard to undergo a curing reaction at room temperature may be used. In this case, the two base films 1 and 2 are overlapped with each other with the sealing material 12 interposed therebetween, and in a state in which pressure is applied from above and below, the sealing material 12 is, as described above, despite the room temperature.
However, the curing reaction of the thermosetting adhesive of the cloth material does not proceed. As a result, the thermosetting adhesive of the cloth material has fluidity, so that the conductive particles of the cloth material are surely brought into contact with the connection terminals (not shown) of the base films 1 and 2 facing each other. You can
Then, when the heat treatment is performed for the main curing of the sealing material 12, the thermosetting adhesive of the cloth material is cured, and the conduction failure in the cloth material portion is reduced.

In the above embodiment, the bonded base films 1 and 2 are cut as shown by a chain line in FIG. 3A, and liquid crystal is injected through the liquid crystal injection port 13 of each cut piece. However, the present invention is not limited to this.
For example, the bonded base films 1 and 2 are cut only in the width direction along the arrangement of the liquid crystal injection ports 13, and in this state, the liquid crystal is injected through the liquid crystal injection port 13 of each cut piece, and then the liquid crystal injection is performed. The inlet 13 may be sealed, and then each cut piece may be cut along the upper cut 31a of the slit 21 in FIG. By doing so, liquid crystal injection and liquid crystal injection port sealing can be efficiently performed. Further, the liquid crystal may be arranged inside the sealant 12 by a supply means such as printing before the base films 1 and 2 are attached to each other.

[0017]

As described above, according to the present invention, since the sealing material made of a material that undergoes a curing reaction at room temperature is used, when the two substrates are bonded together, the sealing material is first gelled at room temperature. When the two substrates are returned to their original state by subsequent cooling, the difference in thermal expansion between the two substrates will almost disappear, and they will be bonded together. In addition, it is possible to prevent both substrates from warping, and it is possible to eliminate the inconvenience caused by the warpage of both substrates.

[Brief description of drawings]

FIG. 1 is a plan view of a part of a rear side base film used in an embodiment of the present invention.

FIG. 2 is a plan view of a part of a front side base film used in the example.

FIG. 3A is a plan view of a part of a state where both base films are bonded together in the same embodiment, and FIG. 3B is its BB.
Sectional drawing which follows the line.

[Explanation of symbols]

 1 Rear side base film 2 Front side base film 12 Sealing material 16 Connection terminal 21 Slit

Claims (4)

[Claims] 1. A liquid crystal display device comprising: two substrates bonded together via a sealing material made of a material that undergoes a curing reaction at room temperature. 2. The cloth material for electrically connecting between the two substrates is made of a material in which conductive particles are mixed with a thermosetting adhesive that is hard to undergo a curing reaction at room temperature. The described liquid crystal display device. 3. The liquid crystal display device according to claim 1, wherein the substrate is a film substrate. 4. The two film substrates are bonded together, and at least one of the two film substrates has an end portion projected from the other film substrate, and a connection terminal is provided on the projected portion. When manufacturing a liquid crystal display device, one of the base film for forming a plurality of the one film substrate, and the other base film for forming a plurality of the other film substrate is prepared, the one of the one A plurality of sets of connection terminals corresponding to the connection terminals of the one film substrate are provided on the base film, and slits are formed at portions corresponding to the plurality of sets of connection terminals of the one base film of the other base film, respectively, One base film and the other base film are attached via a sealing material made of a material that undergoes a curing reaction at room temperature. After combined, by cutting the bonded both the base film was in contact with the slit, the method of manufacturing the liquid crystal display device wherein the liquid crystal display device for a plurality producing, characterized in that.