JP2002328382A - Method of manufacturing liquid crystal display panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a liquid crystal display panel which can manufacture a high-quality liquid crystal display panel with a small size and weight. SOLUTION: A substrate 1 is provided with two display areas, each of which is surrounded by a main seal 2. When a pair of substrates is bonded together, the main seals 2 and space enclosed by the pair of substrates provide sealing spaces 4 in which liquid crystal is sealed. Dummy seals 3 are circularly formed so that the spaces enclosed by the dummy seals 3 do not overlap the sealing spaces 4, and the main seals 2 and the dummy seals 3 do not come into contact with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a liquid crystal display panel used for a personal computer, a liquid crystal television, and the like.

[0002]

2. Description of the Related Art FIG. 7 is a sectional view of an active matrix type liquid crystal display panel 30 which is a typical liquid crystal display panel. The liquid crystal display panel 30 includes an electrode 31 and an alignment film 3.
2. Between a substrate 33 having a thin film transistor (not shown) formed on the surface thereof and a substrate 37 having an electrode 35, an alignment film 36, a light-shielding film (not shown) formed thereon, etc.
It is formed by enclosing a spacer 38 and a liquid crystal 39 with a seal 40.

A liquid crystal 39 is provided between the pair of substrates 33 and 37.
As a method of encapsulating the film, there are a vacuum injection method and a drop bonding method.

FIG. 8 is a schematic view showing a state in which liquid crystal is filled between a pair of substrates bonded by a vacuum injection method. The vacuum injection method is a method of filling a liquid crystal using a pressure difference and a capillary phenomenon, and the liquid crystal is filled in the following steps.

[0005] First, an empty cell 50 is formed by disposing a spacer between a pair of substrates so that the pair of substrates has a predetermined interval, and bonding the pair of substrates by a seal 51. The empty cell 50 is provided with an injection port 53 for injecting liquid crystal when the seal 51 is formed.

Next, the empty cell 50 is placed in a vacuum chamber 52.
Put in. Next, after the inside of the vacuum chamber 52 is evacuated to a predetermined degree of vacuum, an injection port 53 is attached to the liquid crystal 54 contained in the container. Next, the inside of the vacuum chamber 52 is returned to the atmospheric pressure, and the liquid crystal 54 is filled in the empty cell 50 by a pressure difference between the inside and the outside of the empty cell 50.

This vacuum injection method has a drawback that as the size of the liquid crystal display panel to be manufactured increases, it takes time to exhaust the vacuum chamber 52 and to inject the liquid crystal 54 into a vacuum.

On the other hand, in the drop bonding method, the liquid crystal is filled in the following steps. First, a spacer for keeping the distance between the substrates constant is sprayed on one of the pair of substrates, and a seal for bonding the substrates to each other is formed on the one or the other substrate. Then, liquid crystal is dropped on one substrate or the other substrate, and the substrates are bonded to each other in a reduced pressure container. Next, the inside of the decompression container is returned to the atmospheric pressure, and the seal is cured. In such a drop bonding method, the time required to fill the liquid crystal can be significantly reduced as compared with the vacuum injection method.

However, also in the drop bonding method, when a pair of substrates are bonded in a reduced-pressure container and the inside of the container is returned to the atmospheric pressure, the pressure applied to the space in which the liquid crystal is sealed and the pressure applied to the outside of the space. This has the disadvantage that the pair of bonded substrates is distorted due to the difference. Japanese Patent Application Laid-Open No. H11-326922 discloses a method for preventing such a defect and making the distance between a pair of bonded substrates uniform. The drop bonding method disclosed in this publication is performed in the following steps. Since this step is the same as the step of the manufacturing method of the present invention, it will be described with reference to FIG. 5 showing the steps of the manufacturing method of the present invention.

First, in step a1, a main seal 61 and a dummy seal 62 are formed on a substrate 60 as shown in FIG. FIG. 9 is a plan view of the substrate 60 on which the main seal 61 and the dummy seal 62 are formed. The main seal 6 is annularly formed on the substrate 60 so as to surround the display area.
1 is formed, and a dummy seal 62 is formed in an annular shape so as to be outside the main seal 61 and to surround the main seal 61. Here, the main seal is a seal for enclosing the liquid crystal, and the dummy seal is a state in which a pair of substrates are bonded together in a decompression container, and the decompression state is maintained when the inside of the container is returned to the atmospheric pressure. This is a seal for forming a space to be formed. The display area is an area where pixels are arranged.

Next, in step a2, liquid crystal is dropped on the substrate 60. FIG. 10 is a perspective view showing a state before bonding the substrate 60 and the other substrate 63. Spacers 64 for keeping the distance constant are sprayed between the substrate 60 and the substrate 63, and a predetermined amount of liquid crystal 65 is dropped on a portion of the substrate 60 surrounded by the main seal 61.

Next, in step a3, the substrates 60 and 63 are accurately bonded together in a reduced pressure container. FIG. 11 is a cross-sectional view showing a state when the substrates 60 and 63 are bonded in a reduced-pressure container. Space 67 surrounded by main seal 61
However, the liquid crystal 65 has not been filled yet.

Next, in step a4, the inside of the depressurized container is returned to the atmospheric pressure, and the atmospheric pressure is applied to the substrates 60 and 63 in a direction approaching each other. Compress to approximately the same volume as 65. FIG. 12 shows the substrate 60 when the inside of the vacuum container is returned to the atmospheric pressure.
It is sectional drawing of 63. By compressing the space 67 until the space 67 has substantially the same volume as the liquid crystal 65, the dropped liquid crystal 65 fills the space 67.

Next, in step a5, the main seal 6
1 and the dummy seal 62 are cured. Finally, in step a6, a liquid crystal display panel is formed by dividing the liquid crystal display panel into a predetermined size.

Here, in step a3, a space 66 (FIG. 11) between the main seal 61 and the dummy seal 62 is provided.
Is a reduced pressure state. Also, in step a4, even if the inside of the depressurized container is returned to the atmospheric pressure, the space 66 shown in FIG. 12 is in a closed state, and the depressurized state is maintained. Therefore, when atmospheric pressure is applied to the substrates 60 and 63 surrounding the space 66, the space 66 is compressed and narrowed. This serves as a regulating force for keeping the distance between the substrates 60 and 63 around the main seal 61 constant, and a liquid crystal display panel having a uniform distance between a pair of bonded substrates can be manufactured.

[0016]

In the above-mentioned step a4, when the pressure in the decompression vessel is returned to the atmospheric pressure, FIG.
As shown in FIG. 7, the space 67 surrounded by the main seal 61 is filled with the liquid crystal 65, and the pressure in the space 67 becomes substantially equal to the atmospheric pressure. Therefore, a pressure difference occurs between the space 66 and the space 67, and the main seal 61 may be broken before the main seal 61 is cured in step a5.
When the main seal 61 is broken, the enclosed liquid crystal 65
Blows out from the space 67 to the space 66, and the manufactured liquid crystal display panel becomes defective.

As a means for preventing this, the width of the main seal 61 is set to about 1.5 to 2.5 times the width when manufacturing a liquid crystal display panel by a vacuum injection method, and the strength of the main seal 61 is reduced. Means for enhancing are also conceivable. However, if such a measure is taken, the ratio of the area where the liquid crystal is sealed to the entire area of the liquid crystal display panel becomes small. In other words, if the width of the main seal 61 is increased without changing the area in which the liquid crystal is sealed, the area of the entire liquid crystal display panel becomes larger than when the width is not increased. For this reason, means for increasing the width of the main seal 61 is not suitable for liquid crystal applied products aiming at reduction in size and weight.

An object of the present invention is to provide a method of manufacturing a liquid crystal display panel capable of manufacturing a high quality, small and light liquid crystal display panel.

[0019]

According to the present invention, a main seal is formed in an annular shape so as to surround a display area in order to define an enclosed space for enclosing liquid crystal in one of a pair of substrates. Drop the liquid crystal on the substrate or the other substrate,
A liquid crystal display panel in which a liquid crystal is sealed by bonding the pair of substrates under a reduced pressure and then returning to the atmospheric pressure so that the pair of substrates bonded to each other has a predetermined interval, and the main seal is cured. In the manufacturing method, an annular dummy seal is provided on the one substrate or the other substrate so that a space surrounded by the dummy seal and the sealing space do not overlap when the substrates are bonded to each other, and A method for manufacturing a liquid crystal display panel, wherein a seal is provided so as not to contact the dummy seal.

According to the present invention, the annular dummy seal is
When the substrates are bonded to each other, the space enclosed by the dummy seal and the sealing space do not overlap, and the main seal and the dummy seal are provided so as not to contact with each other. If the inside of the container is returned to the atmospheric pressure after bonding the pair of substrates, the pressure in the sealed area is filled with the liquid crystal and becomes the atmospheric pressure. Further, since the space outside the sealed area is not in a sealed state, the pressure is equal to the atmospheric pressure. Therefore, there is no pressure difference between the space surrounded by the main seal and the space outside the space. Therefore, the main seal is not broken.

Further, the present invention is characterized in that the width of the dummy seal is 1.5 times or more the width of the main seal when the pair of substrates bonded to each other has a predetermined interval. .

According to the present invention, the width of the dummy seal when the pair of substrates bonded to each other is at a predetermined interval is at least 1.5 times the width of the main seal.
Strength increases. Therefore, the dummy seal is not broken by the pressure difference between the space surrounded by the dummy seal and the space outside the dummy seal.

Further, in the present invention, the dummy seal is a peripheral portion of the enclosed space, and unless the dummy seal is provided, the pair of substrates bonded when returning to atmospheric pressure does not have a predetermined interval. It is provided at a position close to the portion.

According to the present invention, the dummy seal is provided only at a position close to the peripheral portion of the sealed space where the pair of substrates bonded to each other when the pressure is returned to the atmospheric pressure unless the dummy seal is provided does not have a predetermined interval. Is provided, the amount of material used for the dummy seal is reduced as compared with the case where the dummy seal is provided close to the entire periphery of the main seal.

Further, the present invention is characterized in that, after the main seal and the dummy seal are cured, unnecessary portions of the pair of substrates bonded to each other are cut.

According to the present invention, after the main seal and the dummy seal are cured, unnecessary portions of the pair of substrates bonded to each other are cut, so that the manufactured liquid crystal display panel is reduced in size and weight. You.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The manufacturing method of the present invention will be described below by taking as an example a case where two liquid crystal display panels are manufactured from a pair of substrates. FIG. 5 is a process chart of a method for manufacturing a liquid crystal display panel according to the present invention.

First, in step a1, a main seal 2 and a dummy seal 3 are formed on a substrate 1 as shown in FIG. FIG. 1 is a plan view of a substrate 1 on which a main seal 2 and a dummy seal 3 are formed. The substrate 1 is provided with two display areas, and a main seal 2 is formed around each of the display areas so as to surround the display area. When a pair of substrates are bonded to each other, a space surrounded by the main seal 2 and the pair of substrates becomes a sealed space 4 in which liquid crystal is sealed. The shape formed on the substrate 1 by the main seal 2 is rectangular. The dummy seal 3 is formed in an annular shape so that a space surrounded by the dummy seal 3 does not overlap with the sealing space 4 and that the main seal 2 and the dummy seal 3 do not contact each other. The dummy seals 3 are formed in a total of six places in parallel with the remaining three sides of the main seal 2 except for between two adjacent enclosed spaces 4 surrounded by the main seal 2. The shape formed on the substrate 1 by the dummy seal 3 is a rectangle.

The size of the area surrounded by the dummy seal 3 on the substrate 1 is preferably such that the length of the short side is 5 mm or more and 1
The length of the long side is determined by the side length of the main seal 2, but is generally in the range of several tens mm to several hundreds mm.

In the conventional method, in order to reduce the size and weight of the liquid crystal display panel, the ratio of the main seal 2 to the total area of the liquid crystal display panel is taken into consideration.
Is formed so that the width is usually within a range of 1 mm ± 0.2 mm when a pair of substrates bonded to each other has a predetermined interval. However, in the conventional method, a pressure difference is generated between the space surrounded by the main seal 2 and the space outside the main seal 2, so that the seal width is easily broken at such a seal width. on the other hand,
If the manufacturing method of the present invention is applied, there is no pressure difference between the space surrounded by the main seal 2 and the space outside the main seal 2. The main seal 2 cannot be broken. Therefore, it is not necessary to increase the strength by increasing the width of the main seal 2, and the size and weight of the liquid crystal display panel can be reduced. The width of the dummy seal 3 will be described later.

As a method of forming the main seal 2 and the dummy seal 3, a dispenser drawing method, a screen printing method and the like can be mentioned.

Next, in step a2, as shown in FIG. 2, spacers 9 for keeping the interval constant are scattered between the substrate 1 and the other substrate 8 so as to be surrounded by the main seal 2 of the substrate 1. A predetermined amount of the liquid crystal 10 is dropped on the portion where the liquid crystal has been placed. FIG. 2 is a perspective view showing a state before the substrates 1 and 8 are bonded.

Next, in step a3, in a vacuum container,
As shown in FIG. 3, the substrates 1 and 8 are bonded together with high accuracy so that the main seal 2 and the dummy seal 3 formed on the substrate 1 are in contact with the substrate 8. FIG. 3 is a cross-sectional view showing a state where the substrates 1 and 8 are bonded together. At this time, if the main seal 2 and the dummy seal 3 formed on the substrate 1 are bonded together so as to be in contact with the substrate 8 in the decompression vessel, the bonded substrates are not at a predetermined interval, The space 5 surrounded by the seal 2 is not filled with the liquid crystal. At this time, both the space 5 and the space 6 outside the main seal 2 are in a reduced pressure state. Therefore, there is no pressure difference between the space 5 and the space 6, so that the main seal 2 is not broken and the liquid crystal 10 does not blow out from the space 5.

Next, in step a4, the inside of the depressurized vessel is returned to the atmospheric pressure, and the atmospheric pressure is applied to the substrates 1 and 8 in a direction approaching each other, thereby forming the space 5 as shown in FIG. It is compressed until the volume becomes almost the same as the liquid crystal 10. FIG.
FIG. 3 is a cross-sectional view of the substrates 1 and 8 when the inside of the decompression container is returned to the atmospheric pressure. By compressing the space 5 until the space 5 has substantially the same volume as the liquid crystal 10, the dropped liquid crystal 10 is filled in the space 5. The pressure in the space 5 is equal to the atmospheric pressure. This is because when the liquid crystal 10 is filled and the bonded substrates 1 and 8 have a predetermined interval, the space 5
This is because an amount of the liquid crystal 10 is dropped in advance such that the pressure becomes equal to the atmospheric pressure.

At this time, the annular dummy seal 3 is designed so that the space 7 surrounded by the dummy seal 3 and the space 5 surrounded by the main seal 2 do not overlap, and the dummy seal 3 and the main seal 2 are not overlapped. Are formed so as not to contact with each other, the space 6 is not closed, and the pressure in the space 6 is equal to the atmospheric pressure. Therefore, there is no pressure difference between the space 5 and the space 6, so that the main seal 2 is broken and the liquid crystal 65 does not blow out from the space 5.

Further, since the dummy seal 3 is formed in an annular shape, the space 7 surrounded by the dummy seal 3 is in a sealed state, and the depressurized state is maintained even after the inside of the depressurized container is returned to the atmospheric pressure. Is done. Therefore, when atmospheric pressure is applied to the substrates 1 and 8 surrounding the space 7, the space 7 is compressed and narrowed. This is a regulating force for keeping the distance between the substrates 1 and 8 around the main seal 2 constant.

As described above, the annular dummy seal 3 is
The space 7 surrounded by the dummy seal 3 and the space 5 surrounded by the main seal 2 are formed so as not to overlap with each other, and the main seal 2 and the dummy seal 3 are not in contact with each other. Is not directly surrounded by the space 7. By this, not only can the intervals between the substrates around the main seal 2 be made uniform, but also because the main seal 2 is not broken by the pressure difference and the liquid crystal 10 blows out of the space 5, a high quality liquid crystal display panel can be manufactured. Can be.

Next, in step a5, the main seal 2
Then, the dummy seal 3 is cured. The above steps a1 to
The liquid crystal display panel manufactured by a5 has a space 7 surrounded by the dummy seal 3.

Finally, in step a6, the bonded substrates 1 and 8 are divided into predetermined liquid crystal display panel sizes to form two liquid crystal display panels. At the same time, the unnecessary portion of the liquid crystal display panel is cut. By this cutting, unnecessary portions such as the dummy seal 3 are removed, and the size and weight of the liquid crystal display panel can be reduced.

The width of the dummy seal 3 formed in the above-mentioned step a1 is set to be at least 1.5 times the width of the main seal 2 when the bonded substrates 1 and 8 have a predetermined interval. Set.

The reason why the width of the dummy seal 3 is set to 1.5 times or more the width of the main seal 2 is as follows. Assuming that the width of the dummy seal 3 is the same as the width of the main seal 2, if a pressure difference occurs between a space surrounded by the dummy seal 2 and a space outside the space, the dummy seal 3 is easily broken. Therefore, by making the width of the dummy seal 3 1.5 times or more the width of the main seal 2, the dummy seal 3 is not broken even when a pressure difference between the space 6 and the space 7 occurs.

When the width of the dummy seal 3 is at least 2.5 times the width of the main seal 2, the ratio of the area occupied by the dummy seal 3 to the area of the liquid crystal display panel increases. Therefore, many materials such as a substrate and a seal for manufacturing one liquid crystal display panel are required, and the cost is increased. Therefore, it is preferable that the width of the dummy seal 3 is not more than 2.5 times the width of the main seal 2.

Specifically, the width of the main seal 2 when the bonded substrates 1 and 8 are at a predetermined interval is preferably 1 mm, and the width of the dummy seal 3 is preferably
The range is 1.5 mm or more and 2.5 mm or less. Note that the width of the main seal 2 may be a range including 0.8 mm or more and 1.2 mm or less, which is a range including an error of ± 0.2 mm.

By setting the width of the dummy seal 3 to 1.5 times or more the width of the main seal 2 as described above, the strength of the dummy seal 3 is increased and the dummy seal 3 is not broken.
Therefore, the space 7 is kept in a reduced pressure state, and the atmospheric pressure is applied to the substrates 1 and 8 surrounding the space 7, so that the space 7 is compressed and narrowed. These are the substrates 1, 8 around the main seal 2.
Is a regulating force to make the interval of the constant. Therefore, a liquid crystal display panel in which the distance between the bonded substrates 1 and 8 is uniform can be manufactured.

In this embodiment, the liquid crystal 10 is dropped on the substrate 1 on which the main seal 2 and the dummy seal 3 are formed, but may be dropped on the other substrate 8. Further, the main seal 2 and the dummy seal 3 may be provided on different substrates, respectively, and in this case, the liquid crystal 10 may be dropped on either substrate.

Further, in this embodiment, a case where two liquid crystal display panels are manufactured from a pair of substrates has been described. However, the present invention is also applicable to a case where one liquid crystal display panel is manufactured from a pair of substrates. Applicable. In addition, 3
The present invention can be applied to a case where more than two liquid crystal display panels are manufactured.

As described above, when a plurality of liquid crystal display panels are manufactured from a pair of substrates, the substrates 1 and 8 are bonded together in a reduced-pressure container, and then the container is returned to atmospheric pressure.
Atmospheric pressure is applied to the substrates 1 and 8 surrounding. This serves as a regulating force for making the distance between the substrates in the peripheral portion of the other enclosed space 4 adjacent to the enclosed space 4 uniform. Therefore, it is not necessary to provide the dummy seal 3 between the adjacent enclosing spaces 4, and the amount of material used for the dummy seal 3 per liquid crystal display panel is reduced. Therefore, a liquid crystal display panel can be manufactured at low cost.

Further, the dummy seal 3 does not have to be provided close to the entire peripheral portion of the enclosing space 4 as shown in FIG. 1, but is a peripheral portion of the enclosing space 4 and If it is not provided, it may be provided at a position close to a portion where the pair of substrates bonded at the time of returning to the atmospheric pressure does not have a predetermined interval.

For example, like the substrate 20 shown in FIG.
If the enclosed space 4 at which the bonded substrates do not reach the predetermined interval even when the pressure is returned to the atmospheric pressure is only at the corner of the enclosed space 4, the dummy seal 2 is provided only at a position close to the corner.
2 may be formed. In such a case, since the dummy seals 22 need only be provided at necessary places, the amount of material used for the dummy seals 22 is smaller than when the dummy seals 2 are provided on the entire peripheral portion of the sealing space 4. A liquid crystal display panel can be manufactured at low cost.

The shape of the dummy seal 3 in the present embodiment is rectangular, but may be another shape such as an ellipse.

[0051]

As described above, according to the present invention, there is no pressure difference between the inside and outside of the space surrounded by the main seal, and the main seal is not broken. Therefore, a high-quality liquid crystal display panel can be manufactured without blowing out liquid crystal from the space surrounded by the main seal. Further, since it is not necessary to increase the width of the main seal in order to increase the strength of the main seal, a small and lightweight liquid crystal display panel can be manufactured.

Further, according to the present invention, the dummy seal is not broken by the difference between the pressure in the space surrounded by the dummy seal and the pressure in the space outside the dummy seal. Therefore, a regulating force is generated on the substrate around the main seal, and a liquid crystal display panel having a uniform distance between the bonded substrates can be manufactured.

According to the present invention, the amount of material used for the dummy seal is reduced. Therefore, an inexpensive liquid crystal display panel can be manufactured.

According to the present invention, unnecessary portions of the bonded substrates are cut off, so that the manufactured liquid crystal display panel is reduced in size and weight.

[Brief description of the drawings]

FIG. 1 is a plan view of a substrate 1 on which a main seal 2 and a dummy seal 3 are formed.

FIG. 2 is a perspective view showing a state before bonding substrates 1 and 8;

FIG. 3 is a cross-sectional view showing a state in which substrates 1 and 8 are bonded in a reduced-pressure container.

FIG. 4 shows substrates 1 and 8 when the inside of the vacuum container is returned to the atmospheric pressure.
FIG.

FIG. 5 is a process diagram of a drop bonding method.

FIG. 6 is a plan view of the substrate 20 on which the main seal 2 and the dummy seal 22 are formed.

FIG. 7 is a sectional view of an active matrix type liquid crystal display panel 30.

FIG. 8 is a schematic diagram showing a state in which an empty cell 50 is filled with a liquid crystal 54 by a vacuum injection method.

FIG. 9 is a plan view of a substrate 60 on which a main seal 61 and a dummy seal 62 are formed.

FIG. 10 is a perspective view showing a state before bonding substrates 60 and 63.

FIG. 11 is a cross-sectional view showing a state when substrates 60 and 63 are bonded in a reduced-pressure container.

FIG. 12 shows a substrate 6 when the inside of the decompression container is returned to the atmospheric pressure.
It is sectional drawing of 0,63.

[Explanation of symbols]

 1, 8, 20 Substrate 2 Main seal 3, 22 Dummy seal 4 Enclosed space 5, 6, 7 Space 9 Spacer 10 Liquid crystal

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H088 FA01 FA05 FA09 FA19 FA28 2H089 LA41 LA49 NA22 NA25 NA49 PA13

Claims (4)

[Claims] 1. A main seal is formed in an annular shape so as to surround a display area in order to define an enclosed space for enclosing liquid crystal in one of a pair of substrates, and liquid crystal is dropped on the one substrate or the other substrate. A liquid crystal display in which the pair of substrates are bonded together under reduced pressure and then returned to the atmospheric pressure so that the pair of substrates bonded together has a predetermined interval, and the main seal is cured to enclose a liquid crystal. In the panel manufacturing method, the one substrate or the other substrate, an annular dummy seal, so that the space enclosed by the dummy seal and the sealed space do not overlap when the substrates are bonded together.
A method for manufacturing a liquid crystal display panel, wherein the main seal and the dummy seal are provided so as not to contact with each other. 2. The method according to claim 1, wherein the width of the dummy seal is 1.5 times or more the width of the main seal when the pair of substrates bonded to each other has a predetermined interval. The manufacturing method of the liquid crystal display panel described in the above. 3. The dummy seal is located near a peripheral portion of the enclosed space, where the pair of substrates bonded to each other when the pressure is returned to the atmospheric pressure is not a predetermined distance unless the dummy seal is provided. 3. The method according to claim 1, wherein the liquid crystal display panel is provided at a predetermined position. 4. The liquid crystal according to claim 1, wherein after the main seal and the dummy seal are cured, unnecessary portions of the pair of substrates bonded to each other are cut. Display panel manufacturing method.