JP2005043908A - Method for manufacturing liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a liquid crystal display device using a drop injection method wherein an appropriate quantity of the liquid crystal being dropped is determined and dropping is conducted at short time. <P>SOLUTION: With two dispensers 2 and 3 together, liquid crystal is dropped on an aligned film of a surface of an array substrate 20. The dispensers 2 and 3 can drop the amount of liquid crystal of 5mg and 2mg per shot respectively. Using these two dispensers 2 and 3 simultaneously, the liquid crystal is dropped inside a seal agent 22 applied to the surrounding beyond a display area of the array substrate 20. On the array substrate 20 inside the seal agent 22, the almost equal amount of liquid crystal 31 is dropped in a position wherein the diffusion interval between adjoining dewdrops is almost equal and liquid crystal 32 of 2 mg less than the amount being dropped (5mg) of the liquid crystal 31 is dropped in a position wherein liquid crystal diffusion is limited between adjoining liquid crystals 31. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a liquid crystal display (LCD), and more particularly, to a method for manufacturing a liquid crystal display using a dropping injection method when liquid crystal is sealed between substrates.

An active matrix type color liquid crystal display device using a thin film transistor (TFT) as a switching element attracts attention as a mainstream of flat panel displays, and a manufacturing method capable of mass production with high quality is required.
The manufacturing process of the liquid crystal display device is roughly divided into an array process for forming a wiring pattern, a switching element (such as an active matrix type) such as a thin film transistor (TFT), etc. on a glass substrate, an alignment process, an arrangement of spacers, and an opposing process. A cell process for encapsulating liquid crystal between glass substrates, and a module process for mounting a driver IC and mounting a backlight. Among these, in the liquid crystal injection process performed in the cell process, for example, an array substrate on which a TFT is formed and a counter substrate on which a color filter (CF) or the like is formed are bonded to each other through a sealant and then sealed. The liquid is sealed between the substrates by curing the agent, then placing the liquid crystal and the substrate in a vacuum chamber, immersing the inlet opening in the sealant in the liquid crystal, and then returning the chamber to atmospheric pressure (vacuum injection method) ) Is used.

  In contrast, 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 liquid crystal is sealed by bonding the array substrate and the counter substrate in a vacuum. The injection method has attracted attention. The manufacturing process of the liquid crystal display panel by the dropping injection method will be briefly described. First, liquid crystal is dropped from a liquid crystal dropping injection device (not shown) at a plurality of locations on the surface of the array substrate on which switching elements such as TFTs are formed. Next, a common electrode or color filter is 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 counter substrate is diffused by atmospheric pressure. Next, UV light is irradiated to the sealing agent while moving the UV light source in the moving direction along the application area of the sealing agent, and the sealing agent is cured.

  Compared with the vacuum injection method that has been widely used in the manufacture of conventional panels, this dripping injection method can first reduce the amount of liquid crystal material used, and secondly shorten the liquid crystal injection time. Because of the possibility of reducing the panel manufacturing cost and improving the mass productivity, application in the panel manufacturing process is strongly desired.

However, the manufacturing method of the liquid crystal display device using this dropping injection method has a problem that even if the amount of liquid crystal to be dropped slightly changes, the cell gap fluctuates and a predetermined cell gap cannot be obtained. ing.
On the other hand, if a highly accurate dispenser that can finely adjust the dropping amount can be used, it is only possible to drop a predetermined amount of liquid crystal. There is also a problem that the dots need to be dropped and the tact time is delayed, and there are problems that many dropping traces become uneven and cause display defects.

  An object of the present invention is to provide a method of manufacturing a liquid crystal display device using a dropping injection method capable of optimally controlling the dropping amount of liquid crystal and dropping in a short time.

The above-mentioned purpose is a liquid crystal using a dropping injection method in which liquid crystal is injected onto a substrate by dropping the liquid crystal on the substrate and bonding the liquid crystal dropping surface side of the substrate to the counter substrate in a vacuum and then returning to atmospheric pressure. In the method for manufacturing a display device, this is achieved by a method for manufacturing a liquid crystal display device, wherein a plurality of dispensers are used when the liquid crystal is dropped onto the substrate.
In the method for manufacturing a liquid crystal display device according to the present invention, the plurality of dispensers have different liquid crystal dropping amounts per shot.

Also, the above purpose is to use a dropping injection method in which liquid crystal is injected by dropping liquid crystal on a substrate, and attaching the liquid crystal dropping surface side of the substrate to a counter substrate in a vacuum and then returning to atmospheric pressure. In the manufacturing method of the liquid crystal display device, 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 for manufacturing a liquid crystal display device.
In the method for 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 the substrate is tilted in a range of 0 ° to 85 ° with respect to the horizontal direction.

  As described above, according to the present invention, it is possible to realize a dropping injection method that can optimally control the dropping amount of liquid crystal and that can drop in a short time.

A method of manufacturing the liquid crystal display device according to the 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 of 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 substantially in the vertical direction. An elongated rod-like piston 10 is supported in the housing 5 so as to be movable in the vertical direction along a cylindrical central axis. The tip of the piston 10 can move inside the nozzle 16 provided at the vertically lower end of the housing 5. From the opening in the side wall of the casing 5 in the vicinity of the nozzle 16, the liquid crystal in the liquid crystal storage container 14 can flow into the nozzle 16 through the supply pipe 7 along the illustrated arrow. The liquid crystal that has reached the inside of the nozzle 16 is dripped 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 it receives external force. It has become.

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

The air inlets 6 and 8 are connected to the pump controller 26. The pump controller 26 sucks air and feeds air into one of the air inlets 6 and 8 at a predetermined timing.
The dispenser 2 configured as described above drops 5 mg of the liquid crystal 30 per shot. The liquid crystal dripping amount per shot can be adjusted by controlling the vertical movement amount of the piston 10 by using a micro gauge 18 fixed to the piston 10 protruding above the housing 5. It is like that.

  Next, a manufacturing method of 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, liquid crystal is dropped on the alignment film on the surface of the array substrate 20 using two dispensers 2 and 3 together. The dispenser 2 is the same as that described with reference to FIG. 1, and is adjusted to drop 5 mg of liquid crystal per shot. On the other hand, the dispenser 3 has the same structure as the dispenser 2, but the microgauge 18 is adjusted to drop 2 mg of liquid crystal per shot. In FIG. 2A, the illustration of the pump controller 26 for sending air to the dispensers 2 and 3 is omitted for simplicity of explanation and easy understanding, and the arrangement relationship between the dispensers 2 and 3 is omitted. Also exaggerated.

  Using these two dispensers 2 and 3 at the same time, as shown in FIG. 2A, a sealant (or a coating applied in a frame shape around the display area of the array substrate 20 and cured by ultraviolet (UV) irradiation (or The liquid crystal is dropped inside the combination sealant 22) which is cured by the combined use of UV irradiation and heat. In FIG. 2B, 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 adjacent droplets is substantially equal, and between adjacent liquid crystals 31. A state in which 2 mg of liquid crystal 32, which is smaller than the amount of liquid crystal 31 dropped (5 mg), is dropped at a position where liquid crystal diffusion is sparse is shown.

  When the liquid crystal dropping described above is completed, next, as shown in FIG. 3A, the counter substrate 40 in which the common (common) electrode and the color filter are formed in the display region is aligned and placed on the array substrate 20. paste. 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 and 32 between the bonded array substrate 20 and the counter substrate 40 are diffused by atmospheric pressure. Next, as shown in FIG. 3C, the sealing agent 22 is cured by irradiating the sealing agent 22 with UV light 44 while moving the UV light source 42 in the moving direction 46 along the application region of the sealing agent 22. 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.

Thus, this embodiment makes it possible to change the dropping amount of the liquid crystals 31 and 32 according to the dropping position by using a plurality of dispensers when dropping the liquid crystal to a plurality of positions on the array substrate 20. Yes. As described above, the amount of liquid crystal dropped and the dropping pattern are divided into two or more types and the liquid crystal is dropped simultaneously, whereby the liquid crystal in the liquid crystal display panel surface can be diffused quickly and substantially uniformly. The liquid crystal droplets diffuse in a circular shape when the substrates are bonded together, but by compensating for the amount of liquid crystal that corresponds to the area where the liquid crystal diffusion is sparse, the liquid crystal diffuses almost uniformly within the panel surface, and the tact time is reduced. Can be improved.
In the above embodiment, the dispensers 2 and 3 having different liquid crystal dropping amounts per shot are used. However, a plurality of dispensers having the same liquid crystal dropping amount are used in consideration of the size of the liquid crystal dropping area of the array substrate. However, the tact time can be improved.

  Next, a method for manufacturing a liquid crystal display device according to the 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 of manufacturing a liquid crystal display device according to the present embodiment will be described with reference to FIG. 4A shows a side surface of the liquid crystal dropping device, and 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 53 for sending air into the housing 52 are provided. The air supply unit 53 is provided with a regulator 56 for adjusting air pressure and an electromagnetic valve 57 for controlling opening and closing of the air feed. The nozzle 58 on the lower surface of the casing 52 has a circular cross section and a nozzle diameter of 2 mmφ so that the liquid crystal does not drop due to surface tension unless pressure is applied. The plurality of nozzles 58 are provided in a line with an adjacent interval of 5 mm.

  Next, the manufacturing method of the liquid crystal display device by the liquid crystal dropping using this liquid crystal dropping apparatus 50 is demonstrated using 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. When the liquid crystal injection is finished, the liquid crystal dropping device 50 is connected to a support moving member and an air supply device (not shown). In this state, the substrate is placed below the liquid crystal dropping device 50, air is sent from the air supply unit 53 into the housing 52, and the liquid crystal is continuously discharged from the nozzle 58. At the same time, the liquid crystal dropping device 50 and the substrate are moved relatively continuously to diffuse the liquid crystal on the substrate.

  This will be described more specifically with reference to FIG. First, on the glass substrate 41, two CF (color filter) substrates are formed on which an alignment film is formed and a heat combined type UV sealant 22 is applied in a frame shape around the outside of the display area. The rectangular glass substrate 41 has one long side lifted in the Z direction (vertical direction) from a state in which the long side is placed in the X direction and the short side is placed in the Y direction. The entire substrate is placed at an angle of about 5 °. On the glass substrate 41 in this state, the two liquid crystal dropping devices 50 according to the present embodiment are disposed above the long side that is lifted from the horizontal direction inside the heat combined UV sealant 22. Each liquid crystal dropping device 50 is adjusted so that the arrangement direction of the plurality of nozzles 58 and the long side of the glass substrate 41 are substantially parallel, and is connected to a support moving member and an air supply device (not shown). In this state, air is sent from the air supply unit 53 into the housing 52, and the liquid crystal is continuously discharged from the nozzle 58. At the same time, the liquid crystal dropping device 50 is relatively moved so as to continuously descend along the inclination of the glass substrate 41 to diffuse the liquid crystal 35 on the glass substrate 31.

  Since the liquid crystal 35 dropped from the adjacent nozzles 58 comes into close contact with the glass substrate 41, the liquid crystal 35 continuously dropped from the plurality of nozzles 58 as a whole is the length of the glass substrate 41 between the non-dropping surface 20 ′. The surface of the glass substrate 41 flows downward while having a linear boundary in the side direction.

In addition, the height of the dropped liquid crystal is made substantially uniform by controlling the air supply unit 53 so that the pressure in the housing 52 gradually decreases during the relative movement between the liquid crystal dropping device 50 and the glass substrate 41. Can do.
The glass substrate 41 on which the liquid crystal dropping is finished is bonded to an array substrate on which adhesive spacers are dispersed in a vacuum, and then opened to the atmosphere to form a cell gap. Thereafter, UV irradiation is performed, and after the primary curing, the sealing agent 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 a lower surface of a liquid crystal dropping device according to a modification, and FIG. 6B shows a cross section on the same side. The liquid crystal dropping device shown in FIG. 6 is characterized in that a slit-like 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-like nozzle 60 is effective when used for a panel having a large amount of liquid crystal 70 dropped. If the liquid crystal is to be dropped in a smaller range, a shutter 62 that closes a part of the nozzle 60 is provided as shown in FIG. 7B, and the arrangement of the shutter 62 and the shutter amount may be adjusted.

  Moreover, Fig.7 (a) is a perspective view of the liquid crystal dropping apparatus which concerns on another modification, FIG.7 (b) has shown the same side cross section. 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 having a large amount of liquid crystal 70 dropped. 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 air pressure control using the air supply unit 53. become.

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

It is a figure which shows the dispenser used with the manufacturing method of the liquid crystal display device by the 1st Embodiment of this invention. It is a figure explaining the manufacturing method of the liquid crystal display device by the 1st Embodiment of this invention. It is a figure explaining the manufacturing method of the liquid crystal display device by the 1st Embodiment of this invention. It is a figure explaining the manufacturing method of the liquid crystal display device by the 2nd Embodiment of this invention. It is a figure explaining the manufacturing method of the liquid crystal display device by the 2nd Embodiment of this invention. It is a figure explaining the modification of the manufacturing method of the liquid crystal display device by the 2nd Embodiment of this invention. It is a figure explaining the other modification of the manufacturing method of the liquid crystal display device by the 2nd Embodiment of this invention.

Explanation of symbols

2, 3 Dispenser 5, 52 Housing 6, 8 Air inlet 10 Piston 12 Bulkhead 14 Liquid crystal storage container 16, 58, 60, 68 Nozzle 18 Micro gauge 20 Array substrate 22 Sealing agent 26 Pump controllers 31, 32, 35, 70 Liquid crystal 40 Counter substrate 41 Glass substrate 42 UV light source 44 UV light 50 Liquid crystal dropping device 53 Air supply unit 56 Regulator 57 Electromagnetic valve 62 Shutter

Claims (5)

Manufacture of a liquid crystal display device using a dropping injection method in which liquid crystal is dropped on a substrate, and the liquid crystal dropping surface side of the substrate is opposed to a counter substrate and bonded in a vacuum and then returned to atmospheric pressure. In the method
A method of manufacturing a liquid crystal display device, wherein a plurality of dispensers are used when the liquid crystal is dropped onto the substrate. In the manufacturing method of the liquid crystal display device of Claim 1,
The method for manufacturing a liquid crystal display device, wherein the plurality of dispensers differ in the amount of liquid crystal dropped per shot. Manufacture of a liquid crystal display device using a dropping injection method in which liquid crystal is dropped on a substrate, and the liquid crystal dropping surface side of the substrate is opposed to a counter substrate and bonded in a vacuum and then returned to atmospheric pressure. In the method
A liquid crystal display device manufacturing method, wherein the liquid crystal is continuously dropped while continuously moving a liquid crystal dropping position on the substrate, and the dropped liquid crystal is allowed to flow and diffuse on the substrate. In the manufacturing method of the liquid crystal display device of Claim 3,
A method of manufacturing a liquid crystal display device, wherein the liquid crystal is dropped through a plurality of nozzles. In the manufacturing method of the liquid crystal display device according to claim 3 or 4,
A method of manufacturing a liquid crystal display device, wherein the liquid crystal is dropped by tilting the substrate in a range of 0 ° to 85 ° with respect to a horizontal direction.

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