JPH09222611A - Production of liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing a liquid crystal display device capable of improving the yield of production, obtaining a uniform cell thickness and obviating the peeling of sealing parts at the time of cutting. SOLUTION: Liquid crystals are sealed between two substrates 3 with electrodes. A sealant 1 for sealing the liquid crystals and a dummy sealant on the circumference thereof are arranged between the substrates 3 and after the curing of the sealants, the substrates 3 are cut to allow the necessary electrode terminals to remain in the position between the sealant 1 for sealing the liquid crystals and the dummy sealant. The dummy part is formed in the position apart >=10mm from the sealing part for sealing the liquid crystals or the line width thereof is set at 1/3 the line width of the sealing part for sealing the liquid crystals. The diameter of the spacer materials to be compounded with the inside of the sealant in the dummy part is set larger by 1 to 3% than the diameter of the spacer materials in the sealant of the sealing part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a liquid crystal display device that can be used as a display device for many electronic devices.

[0002]

2. Description of the Related Art Conventionally, in order to manufacture a liquid crystal display device in which a liquid crystal is sealed between two substrates which have been subjected to an alignment treatment, a spacer material is dispersed over at least one of two glass substrates with electrodes, A thermosetting sealant for liquid crystal encapsulation is placed on the other substrate using screen printing, etc., and then the two substrates are bonded together and aligned, and vacuum packaging is performed to obtain a uniform cell thickness. A well-known method is to pressurize a substrate by utilizing the method and heat cure the sealing agent. After the sealant is heated and hardened, the substrate is scribed so as to leave the necessary electrode terminal portions, and the substrate is broken by the pressure plate.

It is also well known that a more uniform cell thickness can be obtained by incorporating a spacer material corresponding to the cell thickness, that is, mainly glass fiber, into the sealant. That is, especially regarding a substrate having a color filter, there are many restrictions on the design such as enlargement of the display area, downsizing of the liquid crystal panel, and enlargement of the mounting area. Therefore, the place where the sealant is formed is
It is often set at various different positions such as on the black matrix or on the color filter. Therefore, correspondingly, the diameter of the glass fiber as the spacer material mixed in the sealant and the particle diameter of the spacer material dispersed in the display portion are adjusted to obtain a uniform cell thickness. It is devised.

[0004]

In such a conventional method of manufacturing a liquid crystal display device, a sealant for sealing the liquid crystal is arranged on the substrate in a pattern surrounding the display area. However, if the seal portion is formed with such a pattern, the substrate warps when the heat curing of the sealant is subsequently performed, or the glass substrate cannot be vertically separated when the glass substrate is cut, and the electrode terminal portion cannot be separated. There is a problem that the yield is deteriorated due to the remaining portion such as the hem.

Further, in a substrate having a color filter, the leveling layer formed on the color filter in order to obtain smoothness of the substrate has weak adhesion to the glass substrate and the electrode such as ITO. Therefore, when the sealing agent is placed at the position of the leveling agent, the color filter, or the black matrix, the leveling layer and the black matrix or the color filter are cut when the glass substrate is cut after the substrates are bonded and the sealing agent is cured. Peeling is likely to occur between the black matrix or the color filter and the glass substrate.

Further, in the substrate with the color filter,
Since the leveling agent layer formed is softer than the spacer material in the sealing material, pressure work such as vacuum packaging to obtain a uniform cell thickness after sticking the substrates together and sealing material Due to curing shrinkage or the like that occurs during curing, the spacer material in the sealant is depressed in the leveling layer, so that an appropriate cell thickness cannot be obtained and display unevenness appears.

Therefore, particularly in the future, as the substrate size becomes larger and thinner, the substrate tends to warp when the sealant shrinks due to ultraviolet curing or heat curing, and the substrate may be stressed during alignment. It is expected that gap defects such as ripples will occur more easily.

Therefore, the present invention is intended to solve the above problems, to improve the production yield of liquid crystal display devices, to obtain a uniform cell thickness, and to eliminate the peeling of the seal portion at the time of cutting. And a method for manufacturing the liquid crystal display device.

[0009]

In order to solve the above problems, the present invention provides a sealant for sealing a liquid crystal when manufacturing a liquid crystal display device in which a liquid crystal is sealed between two substrates with electrodes. And the dummy sealant around it are placed between the substrates, and after the sealant is cured, the necessary electrode terminals are left at a position between the sealant that seals the liquid crystal and the dummy sealant. The substrate is cut.

More specifically, the method of the present invention comprises, for example, a step of forming a sealed portion with a sealing agent, a step of laminating a substrate with electrodes via a spacer material, and the substrate for obtaining a uniform cell thickness. The pressurizing step, the step of curing the sealant, and the step of cutting the substrate leaving the necessary electrode terminals. More specifically, by using screen printing or the like, a seal pattern for sealing the liquid crystal is formed on at least one of the substrates with an ultraviolet curing or thermosetting resin, and a dummy seal is formed around the seal pattern. After forming a pattern and pasting both substrates, a uniform cell thickness is obtained by a pressure means such as vacuum packaging or atmospheric pressure or the use of a weight, and the sealing agent is cured by ultraviolet irradiation or heating, Finally, cutting is performed so that the necessary electrode terminals are left.

Therefore, according to the method of the present invention, when the seal portion is formed on the mother substrate, since the dummy pattern is formed in addition to the pattern for sealing the liquid crystal, the substrates are bonded and the sealant is cured. At the time of cutting both substrates after the cutting, the hem does not remain in the cut portion and the chipped portion of the substrate does not occur, and the electrode terminal portion required for mounting can be manufactured with high yield. Further, this dummy pattern also has an effect that the displacement of the substrate is unlikely to occur during alignment after the substrate bonding process.

According to the present invention, in the case of a substrate with a color filter, it is preferable that the line width of the dummy sealant is approximately one third of the line width of the liquid crystal sealing sealant. Is. Further, when the liquid crystal panel is designed so that the mother substrate has a margin, it is preferable to form the dummy pattern of the seal at a position separated by at least 10 mm from the seal pattern for sealing the liquid crystal.

That is, according to the present invention, the line width of the dummy pattern is set to approximately one-third of the line width of the sealant for sealing the liquid crystal, so that the seal portion for sealing the liquid crystal is cut when the substrate is cut. It is possible to disperse the stress toward the dummy pattern and prevent the occurrence of peeling as described above. Also, the stress applied when cutting such a board is
It depends not only on the balance of the adhesive strength between the dummy pattern and the liquid crystal sealing pattern, but also on the balance of the pressure when cutting into the dummy pattern and the liquid crystal sealing pattern.
In this case, there is a relationship between the cutting position and the seal position, and if the dummy pattern is at a position at least 10 mm away from the liquid crystal sealing seal pattern, the above-described peeling will occur even when the substrate having the color filter is cut. It can be prevented from occurring.

Further, according to the present invention, when a substrate with a color filter is used, it is preferable to mix a spacer material with the sealant. However, the liquid crystal is sealed in the sealant used for the portion corresponding to the dummy pattern of the seal. 1% or more and 3% or more than the spacer material mixed in the sealant for stopping
It is preferable to add a spacer having a diameter of not more than%. The mixing ratio is preferably 1% by weight to 3% by weight in both the liquid crystal sealing portion and the dummy portion.

In particular, in the case of screen printing, a substrate on which a seal pattern for liquid crystal sealing is formed in order to prevent the spacer material mixed in the liquid crystal sealing sealant and the spacer material mixed in the dummy sealant from being mixed. It is desirable to form a dummy seal pattern on the counter substrate.

That is, the average diameter of the spacer material mixed in the sealant for forming the dummy pattern is 1% of the average diameter of the spacer material mixed in the sealant for sealing the liquid crystal.
By increasing the amount by not less than 3% and not more than 3%, the occurrence of display unevenness due to the difference in cell thickness as described above can be prevented. Further, the occurrence of such display unevenness due to the difference in cell thickness can be prevented by simultaneously tapering the glass substrate.

[0017]

EXAMPLES A method of manufacturing a liquid crystal display device according to an example of the present invention will be described below with reference to the drawings and tables. In addition,
In the following examples, screen printing was adopted for forming the sealant. The screen plate used had an emulsion thickness of 20 μm and a line width of 0.24 mm. As the sealant, glass fiber manufactured by Mitsui Toatsu Co., Ltd. was used.

Example 1 As shown in FIG. 1, an alignment film 2 is designed so that two 10.4 inch liquid crystal panels can be taken on a mother glass substrate 3 having a size of 300 mm × 375 mm × 0.7 mm. By forming, a seal pattern with an ITO electrode subjected to orientation treatment was formed. As shown in FIG. 1, the portion sealed by the sealant 1 is the alignment film 2
It was formed so that it would not cover. In addition, a seal portion made of a dummy sealant 6 was formed around the sealant 1 at a constant distance from the sealant 1. FIG. 2 shows FIG.
As shown in FIG. 3, the counter substrate of the substrate 3 on which the sealants 1 and 6 are arranged is bonded to the substrate 3. This counter substrate was made of a glass substrate with an ITO electrode similarly subjected to orientation treatment, and a spacer material 5 having a particle size of 7.4 μm was dispersed between these substrates and the counter substrate. Sealant 1,6
Were crushed between the substrates by the pressing process. In this way, the substrates were attached to each other, and the sealants 1 and 6 were cured by heating at 150 ° C. for 1 hour to form a liquid crystal panel. As the sealants 1 and 6, tract bond made by Spae was used. The seal line width was set to 1 mm.

More specifically, the position where the dummy pattern of the dummy sealant 6 is formed is the sealant 1 for sealing the liquid crystal.
2.5m in the direction of the short side of the mother board 3, measured from the center of
m, and a distance of 4 mm in the long side direction. The length of the dummy portion was set to be the same as the length of the sealing portion for sealing the liquid crystal.

Next, the substrates 3 and 3 after the sealing agents 1 and 6 were cured were cut under the following conditions. That is, FIG.
Indicates the position of the scribe, and the position of the scribe was set to a place 0.1 mm from the sealant 1 that sealed the liquid crystal. Reference numeral 8 is a head portion of the scriber, and a cutter 9 is provided on the head portion 8. In FIG. 3, 11 indicates an electrode. FIG. 4 is a schematic view showing a state in which a substrate is broken after being scribed. As shown in the figure, the scribed substrate 3 is placed on the lower side, and the head portion 12 of the pressing machine is installed on the portion of the upper substrate 3 corresponding to the scribed portion 13, and the head portion 12 is vertically set at a pressure of 2.2 kg / cm ^2. pushed.

This cutting method was applied to a substrate with and without a dummy pattern of the sealant 6 to give 100
Table 1 shows the defective items and the occurrence rate thereof when cutting one substrate. Here, the bottom of the defective item is shown in FIG.
As shown in (4), the substrate does not cut vertically at the time of break, and the end face remains like the hem 14.

[0022]

[Table 1]

As can be seen from Table 1, 87% of the substrates on which the dummy patterns were formed could be adopted as good products. In particular, regarding the skirt 14, the occurrence rate is 0% when the dummy pattern is present, whereas the occurrence rate is 35% when the dummy pattern is not present, which is a large difference. This is because if there is no dummy pattern, the substrate warps at the time of break and the pressure is not applied vertically, and as a result, the hem 14 is generated. However, if there is a dummy pattern, the substrate does not warp at the time of break, so the pressure is applied vertically. This is because the cutting end face is vertical.

(Embodiment 2) FIG. 6 is a sectional view of a substrate with a color filter. In this substrate with a color filter, the color filters 16 are formed by applying paints of R, G, and B in stripes between the black matrices 15 on the glass substrate 3 by using a method such as printing, and then smoothing the substrate. Leveling layer 1 for maintaining properties
7 was formed. For the leveling layer 17, an acrylic ultraviolet curable resin is used. Then, ITO 11 was formed on the leveling layer 17 by sputtering and the pattern was removed. 2 indicates an alignment film. FIG. 7 shows a state in which a sealing portion made of the sealing agents 1 and 6 is formed on the substrate 3 with the color filter 16. The size of the substrate 3 used was the same as in Example 1.

The sealant 1 for sealing the liquid crystal was placed outside the black matrix. The sealant 6 forming the dummy portion was formed at a distance of 2.5 mm in the short side direction and 4 mm in the long side direction of the mother substrate 3, measured from the center of the line width of the sealant 1 for sealing the liquid crystal. . The length of the sealant 6 in the dummy portion is the same as the length of the sealant 1 for sealing the liquid crystal.

As shown in FIG. 8, a seal pattern having the same seal pattern as the above and having a seal portion made of the sealant 1 for sealing the liquid crystal formed on the ITO 11 at the position of the black matrix 15 was prepared. Similarly, a seal portion formed of the sealant 1 was formed at a position where only the leveling layer 17 was present, and a seal portion formed at a portion where the color filter 16 was present was prepared.

Then, the peeling strength of the sealant of the liquid crystal panel was measured for each of the above three types of seal forming states and the one in which the seal portion was directly formed on the glass substrate 3. At that time, a struct bond made of stay was used as a sealant, and the curing condition was 150 ° C. for 1 hour. The line width of the seal was 1 mm, and the number of measurement samples was 5. The peel strength was measured by the method shown in FIG. That is, the sample 18 for measurement is fixed to the sample stage 22 raised by the motor 23 by the sample fixing band 21, and the load measuring balance 19 is attached to the end of the sample 18 protruding from the stage 22.
The peeling strength and the peeled portion were measured by applying the pressing rod 20 of. Table 2 shows a summary of the measurement results.

[0028]

[Table 2]

As can be seen from Table 2, the leveling layer 1 is different from the one in which the seal portion is directly formed on the glass substrate 3.
No. 7, the black matrix 15 and the color filter 16 had a peeling strength of only about 30% when the seal portion was formed. Moreover, all the peeling occurred at the interface between the glass substrate 3 and the leveling layer 17, the black matrix 15 or the color filter 16. This means
This means that the adhesion strength between the leveling layer 17, the black matrix 15, the color filter 16 and the glass substrate 3 is weaker than the strength of the seal base material. That is, it means that peeling of the seal portion occurs when a force stronger than the strength shown in Table 2 is applied at the time of cutting break. In particular, when a dummy seal pattern is provided for cutting the glass substrate, there is no place for the pressing force to escape, so peeling may occur at the seal portion.

Therefore, by adjusting the line width of the dummy pattern, it was examined whether there is a condition that the substrate is not chipped or the hem is not left at the time of cutting and that the seal peeling does not occur. Table 3 shows the results. The seal pattern was the same as above, and the number of samples was 100 each.

[0031]

[Table 3]

From this result, the sealant 1 for sealing the liquid crystal
The yield is best when the line width of the dummy sealant 6 is about one-third of the line width of the above. did.

From the above, the line width of the sealant 6 in the dummy part is approximately 3 times the line width of the sealant 1 in the part for sealing the liquid crystal.
It was found that the liquid crystal display device can be produced with a good yield by setting the ratio to one-half.

The mother board 3 has a dimensional allowance,
As long as the dummy part can be formed at a free position to some extent, peeling of the seal part and residue of the hem of the substrate do not occur even when the dummy is formed at a position 10 mm or more away from the position of the sealant 1 for sealing the liquid crystal. It has been found that a liquid crystal display device can be produced with good yield.

(Embodiment 3) FIG. 10 is a cross-sectional view of a substrate having a color filter, which is in a state after cutting the sealing agent and before cutting. As shown, here
1.5% by weight of glass fiber 24 having a diameter of 8.6 μm was mixed in the sealant 1. In addition, the spacer material 5
As an example, 130 resin beads 5 having an average particle size of 7.4 μm
It was sprayed at a rate of pieces / mm ² . The difference in diameter between the glass fiber 24 mixed in the sealant 1 and the spacer material 5 arranged in the display portion is due to consideration of the thickness of the color filter 16. At this time, the leveling layer 17
Is softer than the glass fiber 24, the pressure process (in the case of the liquid crystal panel of FIG. 10, vacuum packaging was used) performed to obtain a uniform cell thickness, and the curing shrinkage of the sealant 1 at the time of heat curing, The glass fibers 27 were buried in the leveling layer 17, a uniform cell thickness could not be obtained, and display unevenness occurred due to the seal crease.

That is, the difference in diameter of the spacer material between the display portion and the seal portion is 1.2 μm, and this difference in diameter causes stress and appears as display unevenness at the seal crease in the display portion. On the other hand, in Example 3 of the present invention, the diameter of the spacer material mixed in the sealant 6 of the dummy portion is made larger than the diameter of the glass fiber 24 mixed in the sealant 1 for sealing the liquid crystal of the display portion. . Further, by tapering the substrate 3, the gap difference between the seal portion other than the display portion and the non-seal portion is made smooth to eliminate stress and prevent display unevenness at the seal crease.

In looking at the relationship between the difference in the diameter of the glass fibers compounded in the sealants 1 and 6 between the liquid crystal sealing portion and the dummy portion and the display unevenness, as shown in FIG. ITO with an alignment film and alignment treatment
Under the same conditions as in Example 1, the mother glass substrate 3 with electrodes was formed with the sealant 1 so as not to cover the black matrix at the part where the liquid crystal is sealed. The sealant 1 has a diameter of 8.6 μm. Glass fiber was blended at 1.5% by weight.

On the other hand, as shown in FIG. 12, as the counter substrate 3, a color filter is not used, and as the spacer material 5, resin beads having an average particle diameter of 7.4 μm dispersed at a rate of 130 / mm ² are prepared. did. Then, in this counter substrate 3, only the seal portion made of the dummy sealant 6 was formed. At this time, the average diameters of the glass fibers blended in the sealant 6 are 8.6, 8.7, 8.9, 9.
It was changed to 1 μm. The blending ratio was 2% by weight. The formation position of the sealant 6 in the dummy portion is measured from the center of the line width of the sealant 1 for sealing the liquid crystal, and the mother substrate 3
2.5 mm in the short side direction and 4 mm in the long side direction. The length of the dummy part is the same as the length of the seal part that seals the liquid crystal, and the line width is 0.3 mm.
And

Table 4 shows the difference in display unevenness at this time. As can be seen from Table 4, when the diameter of the glass fiber blended in the sealant 6 in the dummy portion is between 8.7 and 8.9 μm, the display unevenness was not seen so much. Therefore, glass fibers having a large average diameter of 1% to 3% with respect to the average diameter of the glass fibers 24 mixed in the sealing agent 1 for sealing the liquid crystal should be mixed in the dummy sealing agent 6. It was also found that by tapering the substrate 3, a liquid crystal display device with good display quality can be produced.

[0040]

[Table 4]

When the position of the sealant 6 in the dummy portion is separated from the position of the sealant 1 for sealing the liquid crystal by 15 mm, the average diameter of the glass fibers mixed in the sealant 1 for sealing the liquid crystal is set to On the other hand, when the average diameter of the glass fibers mixed in the sealant 6 in the dummy portion is 3% larger, the margin becomes narrower, but the ratio of the maximum particle diameter difference is 3%.

[0042]

As described above, according to the present invention, when manufacturing a liquid crystal display device in which two alignment-treated substrates with electrodes are sealed with liquid crystal, a sealant for sealing the liquid crystal is produced. In addition, by forming a seal part made of a dummy sealant, the substrates are bonded together, pressure is applied to obtain a uniform cell thickness, and then the sealant is cured to cut the liquid crystal panel produced. At this time, the hem does not remain on the end face of the substrate and the chipping of the substrate does not occur, and the liquid crystal display device can be produced with good yield.

In the case of a substrate having a color filter,
By controlling the line width and the formation location of the seal of the dummy part, the leveling layer, the black matrix, the color filter, and the peeling between the substrate and the substrate, which is formed to obtain the smoothness of the substrate when the liquid crystal panel is cut Can be prevented.

When the spacer material is mixed in the sealant, the average particle size of the spacer material mixed in the dummy seal is increased from 1% to 3% with respect to the seal for sealing the liquid crystal, thereby improving the display quality. A good liquid crystal display device can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing a pattern of forming a sealant on a dummy portion on a substrate in Example 1 of the present invention.

FIG. 2 is a diagram showing a seal pattern after curing of the sealant in Example 1 of the present invention.

FIG. 3 is a schematic diagram showing a scribing process of the liquid crystal panel in Example 1 of the present invention.

FIG. 4 is a schematic view showing a break process after scribing the liquid crystal panel in Example 1 of the present invention.

FIG. 5 is a cross-sectional view showing a state of a skirt generated on an end face after cutting a substrate.

FIG. 6 is a cross-sectional view of a color filter substrate having a general print-type black matrix.

FIG. 7 is a diagram showing a pattern of forming a sealant in a dummy portion on a substrate having a color filter in Example 2 of the present invention.

FIG. 8 is a cross-sectional view of a liquid crystal panel when a seal portion is formed in a leveling layer on a black matrix of a substrate having a color filter.

FIG. 9 is a perspective view for explaining a method for measuring the peel strength of a sealant.

FIG. 10 is a cross-sectional view showing a state in which a spacer material is mixed with a sealant of a liquid crystal panel having a color filter.

FIG. 11 is a diagram showing a state in which a seal portion is formed only on a portion for sealing a liquid crystal of a substrate having a color filter according to the third embodiment of the present invention.

FIG. 12 is a diagram showing a state in which a dummy portion is formed on the counter substrate of the substrate having the color filter according to the third embodiment of the present invention.

[Explanation of symbols]

 1 Sealant formed on a portion for sealing liquid crystal 3 Glass substrate 6 Sealant formed on a dummy portion 11 Electrode

Claims (5)

[Claims] 1. A method of manufacturing a liquid crystal display device comprising a liquid crystal sealed between two substrates with electrodes, wherein a sealant for sealing the liquid crystal and a dummy sealant around the sealant are disposed between the substrates. Then, after curing these sealing agents, the substrate is cut at a position between the sealing agent that seals the liquid crystal and the dummy sealing agent, leaving the necessary electrode terminals. Production method. 2. A black matrix and a color filter are formed on at least one substrate, and a sealant for sealing a liquid crystal is arranged on the black matrix or the color filter, and the line width of the dummy sealant is set. 2. The method for manufacturing a liquid crystal display device according to claim 1, wherein the line width of the sealant for sealing the liquid crystal is approximately one third. 3. A black matrix and a color filter are formed on at least one substrate, and a sealant for sealing a liquid crystal is arranged on the black matrix or the color filter to seal a liquid crystal. The method for manufacturing a liquid crystal display device according to claim 1, wherein the distance between the agent and the dummy sealant is 10 mm or more. 4. A seal for sealing a liquid crystal by forming a black matrix and a color filter on at least one substrate and disposing a sealant for sealing the liquid crystal on the black matrix or the color filter. The agent is compounded with a first spacer material having a constant average diameter, and the dummy sealant is compounded with a second spacer material having an average diameter larger than the first spacer material by 1% or more and 3% or less. Any one of claims 1 to 3 characterized in that
13. The method for manufacturing a liquid crystal display device according to the above item. 5. A sealant containing a first spacer material for sealing liquid crystal is placed on one substrate, and a sealant containing a dummy second spacer material is placed on the other substrate. The method for manufacturing a liquid crystal display device according to claim 4, wherein both substrates are arranged and then bonded to each other.