JP2002040443A - Manufacturing method of liquid crystal display device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To make it possible to easily control the amount of liquid crystal to be sealed in a liquid crystal sealing process by a drop bonding injection method for shortening a manufacturing time, and to achieve a uniform cell gap without bubbles. Thus, the display quality of the liquid crystal display device is improved. A sealant applied to an array substrate is provided.
The liquid crystal 17 is dropped more than the volume of the liquid crystal cell 21 on the array substrate while the opening 18 is formed. After bonding the array substrate 11 and the opposing substrate 12 and then spreading the liquid crystal 17 over the entire surface of the liquid crystal filling area [A] under atmospheric pressure,
The surplus liquid crystal 27 is discharged from the opening 18. Thereafter, the opening 18 is sealed with a sealing material 22, and the sealing agent 14 and the sealing material 2
2 is cured, and the liquid crystal 17 is uniformly sealed in the liquid crystal cell 21.

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 in which liquid crystal is sealed in a display area of the liquid crystal display device.

[0002]

2. Description of the Related Art In a liquid crystal display device in which liquid crystal is sealed between a pair of substrates having electrodes, as a conventional method of sealing liquid crystal, a pair of substrates is bonded with a sealant to assemble a liquid crystal cell. The pressure inside the liquid crystal cell is reduced, then the liquid crystal is injected from the injection hole formed in the sealant by the capillary pressure and the pressure difference between the pressure inside the liquid crystal cell and the atmospheric pressure at atmospheric pressure. An injection method of sealing the injection port with an agent or the like has been applied.

However, in the above-mentioned injection method, since the liquid crystal is injected from a narrow injection port after the substrates are bonded to each other to form a liquid crystal cell, it takes an extremely long time to fill the liquid crystal, and the productivity is extremely poor. Had the problem of saying. In addition, in order to achieve a wide viewing angle with the recent trend toward larger screens and higher image quality of liquid crystal display devices, it is required to increase the substrate area and narrow the gap between the substrates. The use of a liquid crystal having a high viscosity is required for realizing the response, and a longer time is required for filling the liquid crystal display device due to these factors.

As the screen size, the viewing angle, and the response speed increase, the filling time of the liquid crystal becomes longer, and the processing time of the injection process becomes two to three times or more as compared with the conventional injection process time. Would. Actually, in the production line, since the balance with the processing time in other processes is taken into consideration, an increase in the number of injection devices is required, thereby increasing the production cost.

For this reason, as a liquid crystal injection method which does not depend on the substrate size or the gap between the substrates, a drop bonding injection method shown in FIG. 11 has been conventionally developed. That is, a seal pattern 2 is formed on one of the substrates 1 with a sealant, and a predetermined amount of liquid crystal 3 is dropped in a region surrounded by the seal pattern 2 in a water-drop shape, and then the pressure is reduced so that no air bubbles remain in the liquid crystal cell. It is bonded to the other substrate 4 via a spacer below. Thus, the liquid crystal filling area inside the seal pattern 2 and the outside of the seal pattern 2 are spatially divided.

Next, by returning the pressure to the atmospheric pressure, the substrates 1 and 4 are pressed from the outside to the inside by the pressure difference between the inside and the inside of the seal pattern 2. As a result, the seal pattern 2 for bonding the substrates 1 and 4 is crushed, and the liquid crystal 3 is pushed and spread over the entire liquid crystal filling area. After that, the seal pattern 2 is cured, and the filling process of the liquid crystal by the drop bonding method is completed.

[0007]

In the method of drop bonding and injecting, when the amount of liquid crystal dropped is smaller than the volume of the liquid crystal cell, bubbles are easily generated, while the amount of liquid crystal dropped is smaller than the volume of the liquid crystal cell. If the amount is too large, the gap of the liquid crystal cell becomes thick, which causes a problem that display quality is remarkably deteriorated. Therefore, it is originally required that the volume in the liquid crystal cell and the amount of liquid crystal dropped are the same.

However, the volume of the liquid crystal cell changes depending on the diameter or height and the density of the spherical spacers and columnar spacers scattered between the two substrates, and also depends on the amount and position of the sealant applied. The volume changes. Since these factors have variations, the volume in the liquid crystal cell differs for each manufactured liquid crystal cell. Therefore, it is almost impossible to calculate the optimal amount of liquid crystal to be filled before dropping liquid crystal for each cell, it is difficult to control the amount of dropped liquid crystal, and the gap of completed liquid crystal cells varies, resulting in poor display quality. It was the cause of lowering.

Therefore, the present invention solves the above-mentioned problem, and when the liquid crystal is filled by the drop bonding method for shortening the manufacturing time, the amount of liquid crystal to be filled in the liquid crystal cell regardless of the variation in the volume in the liquid crystal cell. Can be controlled according to the volume of the liquid crystal cell, preventing gap variations in the liquid crystal cell after filling the liquid crystal, obtaining uniform and good display quality by making the gap uniform, and reducing costs by improving productivity. It is an object of the present invention to provide a method for manufacturing a liquid crystal display device.

[0010]

According to the present invention, there is provided, as a means for solving the above-mentioned problems, a step of applying a sealant having at least one opening to one of a pair of substrates arranged opposite to each other; A step of dropping liquid crystal in a region surrounded by the sealant on one of the pair of substrates, and after the step of dropping the liquid crystal, bonding the pair of substrates with the sealant under reduced pressure; And a step of returning the pair of substrates bonded to each other with the sealant to atmospheric pressure, and a step of sealing the opening with a sealing material.

According to another aspect of the present invention, there is provided a method of applying a sealant having at least one opening to one of a pair of substrates disposed opposite to each other. A step of dropping liquid crystal in an area surrounded by the sealant, or a step of bonding the pair of substrates with the sealant under reduced pressure after completion of the liquid crystal dropping step; A step of returning the pair of substrates bonded to each other under atmospheric pressure, a step of uniformly pressing the pair of substrates, and a step of sealing the opening with a sealing material. .

With this configuration, the present invention makes it possible to easily control the amount of liquid crystal sealed in the liquid crystal cell to be equal to the volume of the liquid crystal cell, regardless of the amount of liquid crystal dropped. Improves uniformity of liquid crystal cell gap, improves display quality, enables liquid crystal encapsulation by drop bonding method, and shortens manufacturing time for liquid crystal display devices with large screen, wide viewing angle, and high-speed response In addition, the cost is reduced by improving the productivity.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to a first embodiment shown in FIGS. Reference numeral 10 denotes a liquid crystal display element used for a liquid crystal display device such as a liquid crystal monitor and a television. The liquid crystal display element 10 includes an array substrate 11 formed by forming an alignment film 13 after forming a thin film transistor and a pixel electrode on a glass substrate and further performing alignment processing, and forming an alignment film 13 after forming a counter electrode on the glass substrate and further performing alignment processing. The opposing substrate 12 is bonded with a sealant 14 made of, for example, an ultraviolet curable resin, with a predetermined gap therebetween by a spacer 16, and a liquid crystal is filled in a liquid crystal filling area [A] surrounded by the sealant 14. 17 is enclosed. 28
Reference numerals a and 28b denote polarizing plates.

Next, a method for manufacturing the liquid crystal display element 10 will be described. First, after forming an array substrate 11 having pixel electrodes and a counter substrate 12 having counter electrodes, one of the substrates 11, 12, for example, the array substrate 11 is filled with a liquid crystal of 170 mm × 240 mm using a dispenser as shown in FIG. The sealant 14 is applied so as to surround the area [A]. At this time, one opening 18 is provided in the pattern of the sealant 14.

On the other hand, spacers 16 of, for example, .phi.5 .mu.m are sprayed on the opposing substrate 12 to keep the distance between the array substrate 11 and the opposing substrate 12 at a predetermined constant gap width.

Next, a liquid crystal 17 is dropped into a liquid crystal filling area [A] surrounded by a sealant 14 on the array substrate 11. At this time, the required amount of the liquid crystal 17 to be dropped is, for example, a target cell gap of 5 μm and a liquid crystal filling area of 170 m.
Calculated as mx 240mm, theoretically 0.204ml
Becomes Therefore, as shown in FIG. 4, the liquid crystal 17 is placed in the liquid crystal filling area [A] of the array substrate 11 at 0.025 ml by 9 points (0.025 ml × 9) so as to be slightly larger than the theoretical liquid crystal amount. The liquid crystal 17 of 0.01 ml was further dispersed in the opening 18 at one point (0.01 m).
l) Drop the liquid crystal on the array substrate 11 in a total of 0.235 ml.

Next, as shown in FIG. 5, on a stage 19 in a vacuum chamber 20 evacuated by a vacuum pump and evacuated to 0.1 Pa, a liquid crystal 17 is placed in a liquid crystal filling area [A] surrounded by a sealant 14. An array substrate 11 formed by dropping,
The liquid crystal cell 21 is formed by laminating the counter substrate 12 on which the spacers 16 are scattered. In this bonding, by pressing a lower stage (not shown) on which the array substrate 11 is placed against the opposing substrate 12 from below, the sealing agent 14 can be brought into close contact with the opposing substrate 12.

At this time, the opening 18 is formed on the array substrate 11.
Since 0.01 ml of the liquid crystal 17 is also dropped, the array substrate 11 and the opposing substrate 12 are spatially separated from the inside and outside of the liquid crystal cell 21 by the sealant 14 and the liquid crystal 17 dropped into the opening. Is done.

Thereafter, as shown in FIG.
By returning the internal pressure to the atmospheric pressure, the liquid crystal cell 21 is dropped by the liquid crystal 17 dropped into the sealant 14 and the opening 18.
Due to the pressure difference between the inner vacuum region and the atmospheric region outside the liquid crystal cell 21, the array substrate 11 and the counter substrate 12 are pressurized from the outside to the inside surface, and the sealant is crushed to the target cell gap of 5 μm, and the liquid crystal 17 It is spread over the entire surface of the liquid crystal filling area [A] and is filled in the liquid crystal cell 21. At this time, of the liquid crystals 17 dropped on the array substrate 11,
Excess liquid crystal 27 larger than the volume in the liquid crystal cell 21 is discharged from the opening 18 formed in the sealant 14.

Thereafter, the liquid crystal cell 21 is removed from the vacuum chamber 20.
After alignment of the array substrate 11 and the counter substrate 12 on the coating stage 23,
In order to seal the opening 18, a sealing material 22 made of an ultraviolet curable resin is applied to the opening 18 as shown in FIG.

Next, in order to cure the sealant 14 and the sealing material 22, the liquid crystal cell 21 is moved to the ultraviolet irradiation stage 24, and the ultraviolet irradiation lamp 26 seals from the counter substrate 12 side as shown in FIG. The agent 14 and the sealing material 22 are irradiated with ultraviolet rays at an illuminance of 0.1 J / cm ² for 60 seconds to cure the sealing agent 14 and the sealing material 22. Further, the polarizers 28a,
8b is attached to complete the liquid crystal display element 10. A driver IC substrate (not shown) is bonded to the array substrate 11 of the liquid crystal display element 10, and a backlight is arranged to complete a liquid crystal display device.

According to such a manufacturing method, the liquid crystal is dropped onto the array substrate 11 irrespective of the variation in the volume of the individual liquid crystal cells 21 during the liquid crystal sealing by the drop bonding injection method for shortening the liquid crystal sealing process. Of the liquid crystal 17,
By discharging the surplus liquid crystal 27 from the opening 18, it is possible to easily control the optimal amount of liquid crystal to be filled in each liquid crystal cell. Therefore, it is possible to suppress the variation of the gap of the liquid crystal cell 21 and the generation of bubbles after the liquid crystal is sealed, to achieve a uniform gap of the liquid crystal cell 21, and to easily obtain a liquid crystal display device having uniform and good display quality. In addition, even in a liquid crystal display device having a large screen, a wide viewing angle, and a high-speed response, the processing time of the liquid crystal encapsulation process by the drop bonding and injection method can be shortened, and the cost can be reduced by improving productivity.

Next, the present invention will be described with reference to a second embodiment shown in FIG. This second embodiment is similar to the first embodiment.
In the embodiment, the array substrate 11 and the opposing substrate 12
During the alignment, the substrates 1 and 12 are further pressed, and the other parts are the same as those in the first embodiment. Therefore, the same parts are denoted by the same reference numerals and description thereof will be omitted.

In the present embodiment, after the liquid crystal 17 is filled under the atmospheric pressure shown in FIG. 6 of the first embodiment, after the alignment of the array substrate 11 and the counter substrate 12 is performed, In order to further improve the uniformity of the gap, the liquid crystal cell is further pressed. That is, after the alignment of the array substrate 11 and the counter substrate 12 is completed, the liquid crystal cell 2 is placed between the lower pressure stage 31 and the upper pressure stage 32 as shown in FIG.
1 is pressed, and both sides of the array substrate 11 and the counter substrate 12 are evenly pressed. Thereby, the sealant 14 can be particularly evenly crushed, the cell gap in the vicinity of the sealant 14 can be further uniformed, and the gap in the entire liquid crystal filling area [A] can be better uniformized.

Thereafter, as in the first embodiment, the sealing material 2
2 is applied to the opening 18, and the sealant 14 and the sealing material 22 are further cured by the ultraviolet irradiation lamp 26, and the polarizing plate 28
The liquid crystal display element 10 is completed by attaching a and 28b.

According to such a manufacturing method, the excess liquid crystal 27 is discharged from the opening 18 irrespective of the variation in the volume of the individual liquid crystal cells 21 as in the first embodiment, so that the optimum liquid crystal is obtained. The filling amount can be easily controlled, and the gap of the liquid crystal cell 21 and the generation of bubbles can be suppressed, and the gap of the liquid crystal cell 21 can be made uniform. Further, by the pressurizing process after the filling of the liquid crystal, the gap can be made more uniform over the entire area of the liquid crystal cell 21, and a liquid crystal display device having more uniform and good display quality can be obtained. Also, as in the first embodiment, in a liquid crystal display device having a large screen, a wide viewing angle, and a high-speed response, the processing time of the liquid crystal encapsulation process by the drop bonding and injection method is shortened, thereby reducing the cost by improving the productivity. can get.

The present invention is not limited to the above-described embodiment, but can be modified without departing from the spirit of the invention. For example, the opening of the sealant may be provided at a plurality of positions as necessary. Is also good. The position and number of liquid crystal dropping points are not limited, and when a pair of substrates are bonded together, the opening of the sealant is
It suffices if the liquid crystal cell is sealed by the dropped liquid crystal and when the liquid crystal cell is returned to the atmospheric pressure, it can withstand the atmospheric pressure from the outside of the liquid crystal cell and can isolate the inside and outside of the liquid crystal cell.

Further, the structure of the opening of the sealant is also arbitrary. For example, as in another modification shown in FIG. 10, a columnar spacer 38 is formed at a position corresponding to the opening 37 of the sealant 36 of the array substrate 34. Thus, the cell gap in the vicinity of the opening 37 may be kept more uniform. Note that, instead of the columnar spacers, spherical spacers may be sprayed on the openings 37.

The structure of the liquid crystal display element is also arbitrary, and a color filter layer may be formed on an array substrate or a counter substrate. The present invention is also arbitrarily applicable to a method of forming a plurality of liquid crystal display elements simultaneously from a mother glass substrate.

[0030]

As described above, according to the present invention, at the time of liquid crystal encapsulation by the drop bonding and injecting method capable of shortening the manufacturing time, the encapsulation amount of each liquid crystal cell can be easily controlled.
A liquid crystal display device having good display quality can be easily obtained by suppressing the variation in the gap and the generation of bubbles, and making the gap uniform. In addition, even in a liquid crystal display device having a large screen, a wide viewing angle, and a high-speed response, the processing time of the liquid crystal encapsulation process can be reduced, and the cost can be reduced by improving productivity.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating dispersion of a liquid crystal sealing method according to a first embodiment of the present invention.

FIG. 2 is a schematic explanatory view showing a liquid crystal display device according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a state where a sealant is applied to the array substrate according to the first embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a state in which liquid crystal is dropped on an array substrate according to the first embodiment of the present invention.

FIG. 5 is an explanatory view showing a state in which the vacuum chamber is being returned to the atmospheric pressure after the array substrate and the opposing substrate are bonded to each other according to the first embodiment of the present invention.

FIG. 6 is an explanatory diagram illustrating a state where surplus liquid crystal is discharged from an opening according to the first embodiment of the present invention.

FIG. 7 is an explanatory view showing a state in which a sealing material is applied to an opening according to the first embodiment of the present invention.

FIG. 8 is an explanatory diagram showing curing of a sealant and a sealing material according to the first embodiment of the present invention.

FIG. 9 is an explanatory diagram showing a liquid crystal cell according to a second embodiment of the present invention when pressurized.

FIG. 10 is a schematic sectional view showing the structure of an opening according to another modification of the present invention.

FIG. 11 is a schematic explanatory diagram showing a liquid crystal sealing method according to a conventional drop bonding / injection method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Liquid crystal display element 11 ... Array substrate 12 ... Counter substrate 13 ... Alignment film 14 ... Sealant 16 ... Spacer 17 ... Liquid crystal 18 ... Opening 19 ... Stage 20 ... Vacuum chamber 21 ... Liquid crystal cell 22 ... Sealant 23 ... Coating Stage 24: Ultraviolet irradiation stage 26: Ultraviolet irradiation lamp 27: Surplus liquid crystal 28a, 28b: Polarizing plate

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H089 LA07 LA09 MA07Y NA22 NA41 NA44 NA48 QA12 QA14 SA01 TA15 5G435 AA01 AA16 AA17 BB12 EE09 KK02 KK05 KK10

Claims (8)

[Claims] A step of applying a sealant having at least one opening to one of a pair of substrates disposed opposite to each other; and a region surrounded by the sealant on one of the pair of substrates. A step of dropping liquid crystal therein, a step of bonding the pair of substrates with the sealant under reduced pressure after completion of the liquid crystal dropping step, and a step of bonding the pair of substrates bonded with the sealant to atmospheric pressure. A method for manufacturing a liquid crystal display device, comprising: a step of returning to a lower position; and a step of sealing the opening with a sealing material. 2. The method according to claim 1, wherein in the step of returning the pair of substrates to an atmospheric pressure, the opening is closed by the liquid crystal. . 3. The liquid crystal display according to claim 1, wherein in the liquid crystal dropping step, an amount of the liquid crystal dropped is larger than a volume of a region surrounded by the sealant between the pair of substrates. Device manufacturing method. 4. The method according to claim 1, wherein, in the liquid crystal dropping step, the liquid crystal is dropped in a region surrounded by the sealant and the opening. . 5. In the liquid crystal dropping step, the liquid crystal is dispersed and dropped at a plurality of locations within a region surrounded by the sealant, and the liquid crystal is dropped on the opening. 3. The method for manufacturing a liquid crystal display device according to item 1. 6. The method according to claim 1, wherein the sealant is an ultraviolet-curable sealant. 7. The method according to claim 1, wherein a spacer is provided in the opening. 8. A step of applying a sealant having at least one opening to one of a pair of substrates disposed to face each other, and a region surrounded by the sealant on one of the pair of substrates. A step of dropping liquid crystal therein, a step of bonding the pair of substrates with the sealant under reduced pressure after completion of the liquid crystal dropping step, and a step of bonding the pair of substrates bonded with the sealant to atmospheric pressure. A method for manufacturing a liquid crystal display device, comprising: a step of returning the pair of substrates; a step of uniformly pressing the pair of substrates; and a step of sealing the opening with a sealing material.