JP2001133799A - Manufacturing method of liquid crystal display device - Google Patents

Abstract

(57) Abstract: An object of the present invention is to provide a method for manufacturing a liquid crystal display device using a drop-injection method capable of optimally controlling the amount of liquid crystal dropped and dropping the liquid crystal in a short time. A liquid crystal is dropped on an alignment film on the surface of an array substrate using two dispensers. Dispenser 2 can drop 5 mg of liquid crystal per shot,
The dispenser 3 can drop 2 mg of liquid crystal per shot. By using these two dispensers 2 and 3 at the same time, liquid crystal is dropped inside the sealant 22 applied in a frame shape around the outside of the display area of the array substrate 20 as shown in FIG. FIG. 2 (b) shows that approximately the same amount of liquid crystal 31 is dropped on the surface of the array substrate 20 in the sealant 22 at a position where the diffusion distance between the adjacent liquid droplets is substantially equal. This shows a state in which 2 mg of the liquid crystal 32, which is smaller than the drop amount (5 mg) of the liquid crystal 31, is dropped at a position where the liquid crystal diffusion becomes low.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal display (L).
liquid Crystal Display; LC
More particularly, the present invention relates to a method for manufacturing a liquid crystal display device using a drop injection method when sealing a liquid crystal between substrates.

[0002]

2. Description of the Related Art Active matrix type color liquid crystal display devices using thin film transistors (TFTs) as switching elements are attracting attention as the mainstream of flat panel displays, and a high quality and mass production method is required. The manufacturing process of a liquid crystal display device is roughly divided into a wiring pattern and a thin film transistor (TFT) on a glass substrate.
Array process for forming switching elements (in the case of the active matrix type), etc., alignment process, spacer arrangement, cell process for sealing liquid crystal between facing glass substrates, installation of driver IC, mounting of backlight, etc. Is performed. Among them, in the liquid crystal injection process performed in the cell process, for example, an array substrate on which a TFT is formed and a color filter (C
F) After bonding the counter substrate with the formed substrate and the like via a sealant, the sealant is cured, and then the liquid crystal and the substrate are put in a vacuum chamber, and the injection port opened in the sealant is immersed in the liquid crystal. A method (vacuum injection method) of sealing liquid crystal between substrates by returning the inside of the tank to atmospheric pressure is used.

On the other hand, in recent years, for example, a prescribed amount of liquid crystal is dropped on a substrate surface in a frame of a sealant formed in a frame shape around the array substrate, and the array substrate and the counter substrate are bonded together in a vacuum to encapsulate the liquid crystal. Attention has been paid to a drop injection method for performing the above. The manufacturing process of the liquid crystal display panel by the drop injection method will be briefly described. First, a liquid crystal is dropped from a liquid crystal dropper (not shown) onto a plurality of locations on the array substrate surface on which switching elements such as TFTs are formed. Next, a common electrode and a color filter are formed in the display area, and a counter substrate coated with a sealant or the like that is cured by ultraviolet (UV) irradiation around the display area is aligned and attached to the array substrate. . This step is performed in a vacuum. Next, when the bonded substrate is returned to the atmosphere, the liquid crystal between the bonded array substrate and the opposing substrate is diffused by atmospheric pressure. Next, the sealing agent is irradiated with UV light while moving the UV light source in the moving direction along the application region of the sealing agent to cure the sealing agent.

[0004] This drop injection method can greatly reduce the amount of liquid crystal material used, and secondly, can shorten the liquid crystal injection time, as compared with the vacuum injection method widely used in the conventional panel manufacturing. Because it has the potential to reduce the cost of panel production and improve mass productivity, it is strongly desired to apply it in the panel production process.

[0005]

However, in the method of manufacturing a liquid crystal display device using the drop injection method, even if the amount of the liquid crystal dropped slightly changes, the cell gap fluctuates. Is not obtained. On the other hand, the use of a high-precision dispenser that can finely adjust the amount of liquid drop allows only a predetermined amount of liquid crystal to be dropped. There is a problem that the necessity of dropping a dot occurs, and the tact time becomes slow, and there is a problem that a large number of drop marks become uneven to cause display failure.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a liquid crystal display device using a drop-injection method in which the amount of liquid crystal to be dropped can be optimally controlled and the liquid crystal can be dropped in a short time.

[0007]

The object of the present invention is to fill a liquid crystal by dropping liquid crystal onto a substrate, bonding the liquid crystal dropping side of the substrate to a counter substrate in a vacuum, and then returning to atmospheric pressure. In the method of manufacturing a liquid crystal display device using a drop-injection method, when dropping the liquid crystal on the substrate,
This is attained by a method of manufacturing a liquid crystal display device using a plurality of dispensers. In the above method of manufacturing a liquid crystal display device according to the present invention, the plurality of dispensers have different amounts of liquid crystal dropped per shot.

Another object of the present invention is to perform liquid crystal injection by dropping liquid crystal onto a substrate, bonding the liquid crystal dropping surface of the substrate to an opposing substrate, bonding the substrates in a vacuum, and then returning to atmospheric pressure. In the manufacturing method of the liquid crystal display device using the method, the liquid crystal is continuously dropped while continuously moving the liquid crystal dropping position on the substrate, and the dropped liquid crystal is caused to flow and diffuse on the substrate. This is achieved by a method of manufacturing a liquid crystal display device characterized by the above. In the method of manufacturing a liquid crystal display device according to the present invention, the liquid crystal is dropped through a plurality of nozzles. Further, the liquid crystal is dropped while tilting the substrate in a range of 0 ° to 85 ° with respect to a horizontal direction.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a liquid crystal display according to a first embodiment of the present invention will be described with reference to FIGS. First, a schematic configuration of a flanger pump type dispenser used in the method for manufacturing a liquid crystal display device according to the present embodiment will be described with reference to FIG. The dispenser 2 has a hollow cylindrical housing 5 and is used with the central axis of the cylindrical shape directed substantially vertically.
An elongated rod-like piston 10 is supported in the housing 5 so as to be vertically movable along a cylindrical central axis.
The tip of the piston 10 can move inside a nozzle 16 provided at a vertically lower end of the housing 5. From the opening on the side wall near the nozzle 16 of the housing 5,
The liquid crystal in the liquid crystal container 14 can flow into the nozzle 16 through the supply pipe 7 along the arrow shown in the drawing. The liquid crystal that has reached the inside of the nozzle 16 drops from the nozzle 16 depending on the amount of movement of the tip of the piston 10 at the nozzle 16, and is not discharged from the nozzle 16 due to the surface tension of the liquid crystal itself unless subjected to an external force. It has become.

On the side wall of the air chamber in the housing 5, two air inlets 6, 8 provided vertically apart are attached. A partition 12 that separates the air chamber into two is fixed to the piston 10, and the partition 12 can slide with the piston 10 on the wall of the air chamber between the air inlets 6 and 8. I have. Therefore, when air flows into the air chamber from the air inlet 6, the partition wall 12 receives pressure vertically downward and moves downward, and when air flows into the air chamber from the air inlet 8, receives pressure vertically upward and moves upward. Moving. Thereby, the piston 10 can be moved in the vertical direction by a predetermined amount.

The air inlets 6, 8 are connected to a pump controller 26. The pump controller 26 sucks air and sends air to one of the air inlets 6 and 8 at a predetermined timing. The dispenser 2 having the above-described configuration is configured to drop 5 mg of the liquid crystal 30 per shot. The amount of liquid crystal dropped per shot can be adjusted by controlling the amount of vertical movement of the piston 10 using a micro gauge 18 fixed to the piston 10 protruding above the housing 5. It has become.

Next, a method of manufacturing the liquid crystal display device according to the present embodiment will be described with reference to FIGS. FIG.
2A shows a state when the liquid crystal is dropped, and FIG. 2B shows a state immediately after the liquid crystal is dropped on the substrate. First,
As shown in FIG. 2A, the liquid crystal is dropped on the alignment film on the surface of the array substrate 20 by using two dispensers 2 and 3 together. The dispenser 2 is the same as that described with reference to FIG. 1, and is adjusted so that 5 mg of liquid crystal is dropped per shot. On the other hand, the dispenser 3 has the same structure as the dispenser 2, but the micro gauge 18
Is adjusted to drop 2 mg of liquid crystal per shot. In FIG. 2A, the pump controller 26 for sending air to the dispensers 2 and 3 is not shown for simplicity of explanation and easy understanding, and the arrangement relationship between the dispensers 2 and 3 is omitted. Is also exaggerated.

Using these two dispensers 2 and 3 at the same time, as shown in FIG. 2A, a seal which is applied in a frame shape around the outside of the display area of the array substrate 20 and is hardened by ultraviolet (UV) irradiation. Liquid crystal is dropped inside the agent (or a combined type sealant that is cured by a combination of UV irradiation and heat) 22. FIG. 2B shows the array substrate 2 in the sealant 22.
On the zero plane, approximately the same amount of liquid crystal 31 is dropped at a position where the diffusion distance between adjacent droplets is substantially equal, and the amount of liquid crystal 31 dropped at a position where the liquid crystal diffusion between the adjacent liquid crystals 31 is sparse. 5 mg) of the liquid crystal 32 is dropped.

After the completion of the liquid crystal dripping described above, the counter substrate 40 on which common electrodes and color filters are formed in the display area is aligned as shown in FIG. Affix to the substrate 20. This step is performed in a vacuum. Next, when the bonded substrates are returned to the atmosphere, as shown in FIG. 3B, the liquid crystals 31, 32 between the bonded array substrate 20 and the bonded substrate 40 are diffused by atmospheric pressure. Next, as shown in FIG.
The UV light 44 is irradiated on the sealant 22 while moving the UV light source 42 in the moving direction 46 along the application region of the sealant 22, and the sealant 22 is cured. The diffused liquid crystal 34 is sealed between the two substrates 20 and 40 with a predetermined cell gap to complete a liquid crystal display panel.

As described above, in the present embodiment, the array substrate 2
When the liquid crystal is dropped at a plurality of locations on the zero, a plurality of dispensers can be used to change the amount of the liquid crystal 31, 32 depending on the location of the drop. As described above, the liquid crystal can be quickly and almost uniformly diffused in the liquid crystal display panel surface by dividing the liquid crystal drop amount and the drop pattern into two or more types and simultaneously dropping the liquid crystal. Liquid crystal droplets diffuse in a circular shape when the substrates are bonded,
By supplementing the liquid crystal with an amount corresponding to the region where the liquid crystal diffusion is sparse, the diffusion of the liquid crystal is almost uniformly accelerated in the panel surface, and the tact time can be improved. In the above-described embodiment, the dispensers 2 and 3 having different liquid crystal drop amounts per shot are used. Even so, the tact time can be improved.

Next, a method of manufacturing a liquid crystal display according to a second embodiment of the present invention will be described with reference to FIGS. First, a schematic configuration of a liquid crystal dropping device used in the method for manufacturing a liquid crystal display device according to the present embodiment will be described with reference to FIG. FIG. 4A shows a side surface of the liquid crystal dropping device,
FIG. 4B shows the lower surface. The liquid crystal dropping device 50 shown in FIG. 4 has a plurality of nozzles 58 on the lower surface of a hollow elongated rectangular parallelepiped casing 52. On the upper surface of the housing 52,
A dispenser receiving portion 54 for fixing the dispenser 2 shown in FIG. 1 and an air supply portion 5 for sending air into the housing 52
3 are provided. A regulator 56 for adjusting the air pressure and a solenoid valve 57 for controlling opening and closing of the air supply are attached to the air supply unit 53. The nozzle 58 on the lower surface of the housing 52 has a circular cross section and a nozzle diameter of 2 mmφ, and liquid crystal does not drip due to surface tension unless pressure is applied. The plurality of nozzles 58 are provided in a line at an interval of 5 mm adjacent to each other.

Next, a method of manufacturing a liquid crystal display device by dropping liquid crystal using the liquid crystal dropping device 50 will be described with reference to FIG. First, the dispenser 2 is inserted and fixed in the dispenser receiving portion 54, and a predetermined amount of liquid crystal is accurately injected from the dispenser 2 into the housing 52. After the injection of the liquid crystal is completed, the liquid crystal dropping device 50 is connected to a support moving member (not shown) and an air supply device. In this state, the substrate is placed below the liquid crystal dropping device 50, and the
The liquid is continuously discharged from the nozzle 58 by sending air into the inside. At the same time, the liquid crystal dropping device 50 and the substrate are relatively continuously moved to diffuse the liquid crystal on the substrate.

This will be described more specifically with reference to FIG. First, on a glass substrate 41, two CF (color filter) substrates on which an alignment film is formed and on which a heat-combination type UV sealant 22 is applied in a frame shape around the display area are formed.
The rectangular glass substrate 41 has a long side in the X direction and a short side in the Y direction.
One of the long sides is lifted in the Z direction (vertical direction) from the state of being placed along the direction, and the entire substrate is inclined at about 5 ° with respect to the horizontal direction. With respect to the glass substrate 41 in this state, the two liquid crystal dropping devices 50 according to the present embodiment are respectively disposed inside the combined heat type UV sealant 22 and above the long side lifted from the horizontal direction. Each of the liquid crystal dropping devices 50 is adjusted such that the arrangement direction of the plurality of nozzles 58 and the long side of the glass substrate 41 are substantially parallel to each other, and is connected to a support moving member and an air supply device (not shown). In this state, the housing 5
The liquid is continuously discharged from the nozzle 58 by sending air into the nozzle 2. At the same time, the liquid crystal dropping device 50 relatively moves the liquid crystal 35 so as to continuously descend along the inclination of the glass substrate 41 to diffuse the liquid crystal 35 on the glass substrate 31.

The liquid crystal 35 dropped from the adjacent nozzle 58
Are in close contact with each other when they reach the glass substrate 41, so that the liquid crystal 35 continuously dropped from the plurality of nozzles 58 as a whole
The glass flows downward on the surface of the glass substrate 41 while having a linear boundary in the long side direction of the glass substrate 41 with the non-drop surface 20 ′.

The liquid crystal dropping device 50 and the glass substrate 41
The height of the dropped liquid crystal can be made substantially uniform by controlling the air supply unit 53 so that the pressure in the housing 52 gradually becomes weaker during the relative movement of the liquid crystal. The glass substrate 41 on which the liquid crystal dropping has been completed is bonded in vacuum to the array substrate on which the adhesive spacers are scattered, and then opened to the atmosphere to form a cell gap. Then UV
After irradiation and primary curing, the sealant is completely cured by heat curing in an oven. Next, the glass substrate 41 is cut to complete the liquid crystal display panel.

Next, a modification of the method for manufacturing the liquid crystal display device according to the present embodiment will be described with reference to FIGS. FIG. 6A shows the lower surface of a liquid crystal dropping device according to a modification, and FIG. 6B shows the same side cross section. The liquid crystal dropping device shown in FIG. 6 is characterized in that a slit-shaped nozzle 60 is provided instead of the nozzle 58 having a circular cross section of the liquid crystal dropping device 50 shown in FIG. The liquid crystal dropping device 50 having the slit-shaped nozzle 60 is effective when used for a panel in which the amount of the liquid crystal 70 dropped is large. When it is desired to drop the liquid crystal within a smaller range, a shutter 62 for closing a part of the nozzle 60 may be provided as shown in FIG. 7B, and the arrangement and the shutter amount of the shutter 62 may be adjusted.

FIG. 7A is a perspective view of a liquid crystal dropping device according to another modification, and FIG. 7B is a sectional view of the same. The liquid crystal dropping device shown in FIG. 7 is characterized in that, instead of the nozzle 58 having a circular cross section of the liquid crystal dropping device 50 shown in FIG. have. The liquid crystal dropping device 50 having the nozzle 68 is effective when used for a panel where the amount of the liquid crystal 70 dropped is large. Furthermore, if the shutter 62 is provided at the liquid crystal dropping end of the nozzle 68 as shown in FIG. 7B, the liquid crystal 70 can be dropped without using the air pressure control using the air supply unit 53. become.

The present invention is not limited to the above embodiment, but can be variously modified. For example, in the method of manufacturing the liquid crystal display device according to the second embodiment, the liquid crystal is dropped by inclining the glass substrate 41 by 5 ° with respect to the horizontal direction. That is, the substrate may be in a horizontal state, and is applicable within a range of about 85 ° or less, which is the upper limit of the angle at which the liquid crystal can be dropped sufficiently from the liquid crystal dropping device onto the substrate.

[0024]

As described above, according to the present invention, it is possible to realize a dripping injection method capable of optimally controlling the amount of liquid crystal dropped and dropping the liquid crystal in a short time.

[Brief description of the drawings]

FIG. 1 is a view showing a dispenser used in a method for manufacturing a liquid crystal display device according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a method for manufacturing the liquid crystal display device according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating a method for manufacturing the liquid crystal display device according to the first embodiment of the present invention.

FIG. 4 is a diagram illustrating a method for manufacturing a liquid crystal display device according to a second embodiment of the present invention.

FIG. 5 is a diagram illustrating a method for manufacturing a liquid crystal display according to a second embodiment of the present invention.

FIG. 6 is a diagram illustrating a modification of the method of manufacturing the liquid crystal display device according to the second embodiment of the present invention.

FIG. 7 is a view for explaining another modification of the method for manufacturing the liquid crystal display device according to the second embodiment of the present invention.

[Explanation of symbols]

 2, 3 Dispenser 5, 52 Case 6, 8 Air inlet 10 Piston 12 Partition wall 14 Liquid crystal container 16, 58, 60, 68 Nozzle 18 Micro gauge 20 Array substrate 22 Sealant 26 Pump controller 31, 32, 35, 70 Liquid crystal 40 Opposite substrate 41 Glass substrate 42 UV light source 44 UV light 50 Liquid crystal dropping device 53 Air supply unit 56 Regulator 57 Solenoid valve 62 Shutter

Claims (5)

[Claims] A liquid crystal injection method is used in which liquid crystal is dropped on a substrate, the substrate is bonded in a vacuum with the liquid crystal dropping surface side of the substrate facing a counter substrate, and then the pressure is returned to atmospheric pressure. In the method for manufacturing a liquid crystal display device, a plurality of dispensers are used when the liquid crystal is dropped on the substrate. 2. The method for manufacturing a liquid crystal display device according to claim 1, wherein said plurality of dispensers have different amounts of liquid crystal dropped per shot. 3. A drop-injection method in which liquid crystal is dropped on a substrate, and the substrate is bonded in a vacuum with the liquid crystal dropping surface side of the substrate facing a counter substrate and then returned to atmospheric pressure to perform liquid crystal injection. In the method of manufacturing a liquid crystal display device, the liquid crystal is continuously dropped while continuously moving a liquid crystal dropping position on the substrate, and the dropped liquid crystal is caused to flow and diffuse on the substrate. Of manufacturing a liquid crystal display device. 4. A method for manufacturing a liquid crystal display device according to claim 3, wherein said liquid crystal is dropped through a plurality of nozzles. 5. The liquid crystal display device according to claim 3, wherein the liquid crystal is dropped while tilting the substrate in a range of 0 ° to 85 ° with respect to a horizontal direction. A method for manufacturing a display device.