JPH08201837A - Liquid crystal display device and manufacturing method thereof - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve the reliability of the conductive connection of the opposing connection electrodes of both base substrates (film substrates). [Structure] The cloth material 15 is formed by mixing conductive particles 15b in a thermosetting adhesive 15a having a curing shrinkage rate higher than that of the thermosetting adhesive which is a material of the sealing material 5. When the thermosetting adhesive 15a of the sealing material 5 and the cloth material 15 are both thermoset, the thermosetting adhesive 15a of the cloth material 15 shrinks more than the sealing material 5.
Then, the distance between the two base substrates 1 and 11 in the portion where the cross member 15 is interposed becomes smaller than the distance between the two base substrates 1 and 11 in the portion where the seal member 5 is interposed. As a result, the conductive particles 15b bite into the connecting electrodes 3 and 13 of both base substrates 1 and 11 and both base substrates 1 and 11, and the conductive particles 15b penetrate into the connecting electrodes 3 and 13 of both base substrates 1 and 11. Will surely make surface contact.

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 are attached to each other via a sealing material, and connecting electrodes respectively provided on opposite surfaces of both film substrates are conductively connected via a crossing material. There is a structure. In this case, a thermosetting adhesive is used as the sealing material, and as the cloth material, the thermosetting adhesive is mixed with conductive particles obtained by coating the surface of the resin particles with a metal coating such as Ni plating. You may use

In the case of manufacturing such a liquid crystal display device, a sealing material and a cloth material are respectively formed on opposite surfaces of two film substrates, and both film substrates are stacked with the sealing material and the cloth material interposed therebetween. The two film substrates are bonded together by thermocompression bonding through a thermosetting adhesive of the seal material and the cloth material, and the connecting electrodes respectively provided on the opposite surfaces of both film substrates Conductive connection is made through conductive particles. In this case, the conductive particles come into surface contact with the connection electrode by being crushed to some extent.

However, depending on the thermocompression bonding conditions, the conductive particles may not come into contact with each other and may come into point contact with the connecting electrode. Even in such a case, since they are in contact with each other, they are judged to be non-defective even if an electrical inspection is performed. However, the conductive connection by point contact is vulnerable to shock and the like, and a defective conductive connection is likely to occur. Further, the liquid crystal display device may be used at a temperature of room temperature or higher, for example, in the range of 35 to 45 ° C. In such a case, in particular, the thermosetting adhesive of the cloth material undergoes a relatively large thermal expansion, so that the gap between the corresponding connection electrodes of both film substrates is widened. Then, when the conductive particles are crushed to some extent and are in surface contact with the connecting electrode, the conductive particles try to return to the original shape by following the thermal expansion of the thermosetting adhesive, and thus the conductive particles The contact of the conductive particles with the connecting electrode is maintained. On the other hand, when the conductive particles are not crushed and are in point contact with the connecting electrode, the conductive particles cannot follow the thermal expansion of the thermosetting adhesive, resulting in poor conductive connection. Will occur.

[0005]

As described above, in the conventional liquid crystal display device using the cloth material in which the conductive particles are mixed in the thermosetting adhesive, the conductive particles are connected without being crushed. In the case of point contact with the working electrode, there is a problem that conductive connection failure may occur and the reliability of the conductive connection is low. An object of the present invention is to provide a liquid crystal display device and a method of manufacturing the liquid crystal display device, which can improve the reliability of the conductive connection of the connecting electrodes of both film substrates facing each other.

[0006]

According to the present invention, conductive particles are mixed as a cloth material in a thermosetting adhesive having a curing shrinkage higher than that of a thermosetting adhesive which is a material of a sealing material. Is used.

[0007]

According to the present invention, when the thermosetting adhesive of the sealing material and the thermosetting adhesive of the cloth material are both thermoset, the thermosetting adhesive of the cloth material shrinks more than the sealing material. The distance between the two film substrates in the area is much smaller than the distance between the two film boards in the portion where the sealing material is interposed, and as a result, the conductive particles of the cloth material are connected to the connecting electrodes of both the film boards and both the film boards. The conductive particles of the bite material and the cloth material are surely brought into surface contact with the connecting electrodes of the film substrates, so that the reliability of the conductive connection of the opposing connecting electrodes of both film substrates can be improved.

[0008]

1 to 4 show respective manufacturing steps of a liquid crystal display device according to an embodiment of the present invention.
Therefore, the structure of the liquid crystal display device of this embodiment will be described together with its manufacturing method with reference to these drawings in order. First, as shown in FIG. 1, a long lower base substrate 1 for forming a large number of lower film substrates and a long upper base substrate 11 for forming a large number of upper film substrates 11
And prepare.

Then, a lower display electrode 2, an upper substrate external connection electrode 3 and a lower substrate external connection electrode (not shown) made of ITO or the like are provided at predetermined locations on the upper surface of the lower base substrate 1. Form. Next, the lower alignment film 4 is formed at a predetermined position on the upper surface of the lower base substrate 1 including the lower display electrode 2. Next, the sealing material 5 is formed on the upper surface of the lower base substrate 1 around the lower alignment film 4 by screen printing or the like. Although not shown in detail, the sealing material 5 is made of a thermosetting adhesive obtained by mixing about 50 wt% of a metal oxide having a particle diameter of about 1 μm with a thermosetting adhesive made of epoxy resin or the like. The curing shrinkage rate is about 1% or less. Next, spacers 6 having a particle size of about 7 μm are sprayed on the upper surface of the lower alignment film 4 by using a spray or the like.

On the other hand, the upper display electrode 12 and the connection electrode 13 made of ITO or the like are formed on the lower surface of the upper base substrate 11 at predetermined positions. Next, the upper alignment film 1 is formed at a predetermined position on the lower surface of the upper base substrate 11 including the upper display electrode 12.
4 is formed. Next, a cloth material 15 is formed by screen printing or the like on a predetermined portion of the lower surface of the connecting electrode 13 in a portion corresponding to the outside of the sealing material 5. Cloth material 15
Is composed of a thermosetting adhesive 15a made of an epoxy resin and the like, and conductive particles 15b made by coating the surface of resin particles with a metal coating made of Ni plating or the like. In this case, as the thermosetting adhesive 15a, one having a cure reduction rate of about 2 to 3% is used. Conductive particles 1
The particle size of 5b is larger than the particle size of the spacer 6 by about 1 to 3 μm, and is about 8 to 10 μm. In addition, the upper base substrate 1 between each of the plurality of film substrate forming regions
1 has a slit-shaped opening 16.

Next, the two base substrates 1 and 11 are sealed with the sealing material 5.
And, when the thermocompression bonding is carried out by superposing them via the cloth material 15,
As shown in FIG. 2, both base substrates 1 and 11 are made of the sealing material 5.
And the connecting material 3 and 13 of the base material 1 and 11 facing each other while being bonded to each other via the thermosetting adhesive 15a of the cloth material 15 and the conductive particles 15 of the cloth material 15.
Conductive connection is made via b. In this case, since the curing shrinkage rate of the thermosetting adhesive 15a of the cloth material 15 is about 2 to 3%, which is larger than the curing shrinkage rate of the sealing material 5 (about 1% or less), the sealing material 5 and the cloth When the thermosetting adhesive 15a of the material 15 is also thermoset, the thermosetting adhesive 15a of the cloth material 15 shrinks more than the sealing material 5.
Then, the distance between the two base substrates 1 and 11 in the portion where the cross member 15 is interposed becomes smaller than the distance between the two base substrates 1 and 11 in the portion where the seal member 5 is interposed. As a result, as shown in FIG. 3, the conductive particles 15b of the cloth material 15 bite into the connecting electrodes 3 and 13 of the base substrates 1 and 11 and the base substrates 1 and 11, and the conductive particles 15b of the cloth material 15 are formed. Will surely make surface contact with the respective connecting electrodes 3, 13 of the two base substrates 1, 11, and therefore enhance the reliability of the conductive connection between the opposing connecting electrodes 3, 13 of the two base substrates 1, 11. You can

Next, the two base substrates 1 and 11 are formed in the opening 16
2 is divided into individual pieces of each liquid crystal cell by cutting along the right end portion in FIG. 2 and the like to obtain the one shown in FIG. Next, although not shown, liquid crystal is injected between the base substrates (film substrates) 1 and 11 inside the seal material 5 through a liquid crystal injection opening formed in the seal material 5, and then the liquid crystal injection opening. Is sealed with a sealing material. Thus, the liquid crystal display device of this embodiment is manufactured.

In the above embodiment, as shown in FIG. 4, the cloth material 15 is arranged outside the sealing material 5, but the invention is not limited to this. For example, as shown in FIG. 5, the sealing material 5 may be arranged around the cloth material 15. In this case, when the sealing material 5 is formed on the upper surface of the lower base substrate 1 by screen printing or the like, a through hole for accommodating the cloth material may be formed in a portion corresponding to the cloth material 15. In this case, both base substrates (film substrates) 1 and 11 in the portion of the cloth material 15 can be prevented from peeling off easily, and therefore the reliability of the conductive connection can be further enhanced.

Further, in the above-mentioned embodiment, the case where the conductive particles 15b of the cloth material 15 are those in which the surface of the resin particles is coated with a metal coating such as Ni plating is used, but the present invention is not limited to this. However, simple metal particles may be used instead. In this case as well, the metal particles will dig into the connecting electrodes 3 and 13 of both base substrates 1 and 11 and both base substrates 1 and 11, so that the metal particles will connect electrodes 3 of each of the base substrates 1 and 11, 13 will surely come into surface contact.

[0015]

As described above, according to the present invention, when both the thermosetting adhesive of the seal material and the thermosetting adhesive of the cloth material are thermoset, the thermosetting adhesive of the cloth material shrinks more than the seal material. Therefore, the distance between the two film substrates in the portion where the cloth material is interposed is smaller than the distance between the two film substrates in the portion where the sealing material is interposed,
As a result, the conductive particles of the cloth material bite into the connecting electrodes and both film substrates of both film substrates, and the conductive particles of the cloth material surely make surface contact with the connecting electrodes of the film substrate, and therefore, of both film substrates. The reliability of the conductive connection of the connection electrodes facing each other can be improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a state before both base substrates are attached to each other in manufacturing a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a state in which both base substrates are attached to each other when manufacturing the liquid crystal display device.

FIG. 3 is an enlarged cross-sectional view of a part of FIG.

FIG. 4 is a cross-sectional view showing a state in which each liquid crystal cell is divided into individual pieces in manufacturing the same liquid crystal display device.

5 is a sectional view of a liquid crystal display device according to another embodiment of the present invention, similar to FIG.

[Explanation of symbols]

 1, 11 Base Substrate (Film Substrate) 3, 13 Connection Electrode 5 Sealing Material 6 Spacer 15 Cloth Material 15a Thermosetting Adhesive 15b Conductive Particles

Claims (8)

[Claims] 1. A liquid crystal display device in which two film substrates are bonded to each other via a sealing material, and connection electrodes respectively provided on opposite surfaces of the both film substrates are conductively connected via a cross material, The sealing material is made of a thermosetting adhesive, and the cloth material has a curing shrinkage ratio larger than that of the thermosetting adhesive that is the material of the sealing material. And a liquid crystal display device. 2. The liquid crystal display device according to claim 1, wherein the thermosetting adhesive which is a material of the sealing material has a curing shrinkage of about 1% or less. 3. The liquid crystal display device according to claim 2, wherein the thermosetting adhesive of the cloth material has a curing shrinkage of about 2 to 3%. 4. The liquid crystal display device according to claim 1, wherein the diameter of the conductive particles is larger than the diameter of the spacer interposed between the film substrates. 5. A sealing material made of a thermosetting adhesive and a thermosetting adhesive having a curing shrinkage larger than that of the thermosetting adhesive which is a material of the sealing material, respectively, on opposite surfaces of the two film substrates. Forming a cloth material made of a mixture of conductive particles in the agent, and bonding the both film substrates via a thermosetting adhesive of the sealing material and the cloth material, and facing each other of the film substrates. A method for manufacturing a liquid crystal display device, characterized in that the connection electrodes provided on the respective surfaces are electrically connected through the conductive particles of the cloth material. 6. The method of manufacturing a liquid crystal display device according to claim 5, wherein the thermosetting adhesive which is a material of the sealing material has a curing shrinkage of about 1% or less. 7. The method of manufacturing a liquid crystal display device according to claim 6, wherein the thermosetting adhesive of the cloth material has a curing shrinkage of about 2 to 3%. 8. The method of manufacturing a liquid crystal display device according to claim 5, wherein a diameter of the conductive particles is larger than a diameter of a spacer interposed between the film substrates.