JPH0483228A - Manufacturing device for liquid crystal display device - Google Patents

Abstract

PURPOSE:To improve the quality and manufacture efficiency and to simplify the device by providing a reservoir means for liquid crystal which deforms when heated up to predetermined temperature to drip the liquid crystal on the liquid crystal injection port of a liquid crystal element arranged below. CONSTITUTION:A liquid crystal container 33 is fixed on the flank of a vacuum tank 31 with a support rod 32 made of shape memory alloy. The vacuum tank 31 is evacuated to foam the liquid crystal 34 in the container 34 and then the liquid crystal 34 is heated by an infrared-ray lamp 36 to become liquid having low viscosity and further foamed. The support rod 32 is deformed by carrying on the heating and the liquid crystal 34 is dripped on the injection port of a liquid crystal cell 21. The dripped liquid crystal 34 is injected into the liquid crystal cell 21 through the injection port. Consequently, no air bubble is formed in the liquid crystal cell, so the quality of the liquid crystal cell is improved and the liquid crystal is dripped by a fixed amount corresponding to the liquid crystal storage space, so the loss of the liquid crystal is small and the manufacture efficiency is improved. Then no complex control is required, so the device can be simplified.

Description

[Detailed description of the invention] Industrial applications The present invention relates to an apparatus for manufacturing a liquid crystal display device.

BACKGROUND OF THE INVENTION FIG. 8 is a sectional view of a simple matrix type liquid crystal cell 1. Band-shaped electrodes 4a and 4b are arranged on a pair of transparent substrates 2.3 made of glass or resin, and an alignment film 5a
, 5b. These force substrates 2, 3 are connected to electrodes 4a, 4
face each other so that b are perpendicular to each other. Substrate 2.3
The substrates 2 and 3 are bonded together using a sealing material 7 so that a liquid crystal injection port 12 and a liquid crystal storage space 6 are formed between them. At this time, a protrusion 2a of the substrate 2 protruding from the substrate 3 is formed on the injection port 12 side. The liquid crystal cell 1 is completed by injecting the liquid crystal 8 into the liquid crystal injection space 6 through the injection port 6 and sealing the injection port 12. As a method for injecting the liquid crystal 8, a method using capillary action is widely used.

When injecting the liquid crystal 8 into the liquid crystal cell 1, the melting method shown in FIG. 9, the hanging method (not shown), and the dropping method shown in FIG. 10 are widely used. In the case of liquid crystal 8 having strong viscosity such as ferroelectric liquid crystal, either method can be used, but in the case of nematic liquid crystal having low viscosity, the downgrade method is used.

FIG. 9 is a side view of a liquid crystal injection device 9 for explaining the first conventional injection method using the melting method. A base 10 whose upper surface is inclined at an angle θ with respect to the horizontal plane.
On top, install a hot plate (1), which is placed under a heat transfer wire or metal plate. Liquid crystal cell 1 on top 11
Place. The injection port 12 is formed facing the protrusion 2a, and the liquid crystal 8 is installed near the injection port 12 on the protrusion 2a. The base [O] on which the nanodove tote 11 and the liquid crystal cell 1 are arranged is housed in a vacuum chamber 13. The vacuum chamber 13 is
It is connected to a vacuum source 14.

The inside of the vacuum chamber 13 is evacuated using the vacuum source 14 . At this time, the gas contained in the liquid crystal 8 appears outside and forms bubbles. If the injection port 12 is blocked by these air bubbles, the pressure in the liquid crystal storage space 6 in the liquid crystal cell 1 will not be able to be depressurized properly, and sufficient evacuation will not be possible. In the second step (here, in order to prevent the filling port 12 from being blocked by air bubbles, it is necessary to gradually evacuate the inlet 12. Also, in the heating step described later, the temperature of the liquid crystal 8 increases, so the liquid crystal The solubility of the gas contained in 8 decreases,
Gas appears to the outside and blockage of the inlet 12 occurs. For this reason, delicate control of the degree of vacuum and temperature is required, and a process that requires very complicated manual operations is required, making the process complicated. Also, if it is done with an automated machine,
The delicate control described above becomes necessary, and the liquid crystal injection device 9 becomes complicated and large. Therefore, as a modification of the first prior art melting type defoaming process, there is also a method in which the liquid crystal 8 is placed under vacuum in advance, defoamed, and then placed in the liquid crystal injection device 9. However, in this case, although the generation of bubbles can be suppressed to some extent, defoaming becomes insufficient because the material is exposed to normal pressure. Also, since it is necessary to create a vacuum Bt twice,
There is a problem that the number of steps increases.

In the first conventional example, after the liquid crystal 8 is degassed, that is, after the liquid crystal 8 is attached near the injection port of the liquid crystal cell 1, placed in the liquid crystal injection device 9, and the inside of the vacuum chamber 13 is made sufficiently high vacuum, The hot plate 11 is energized, and the liquid crystal cell 1 and the liquid crystal 8
heat up. When the liquid crystal 8 is a ferroelectric liquid crystal, the liquid crystal 8
is greasy at room temperature. Since it has a high viscosity in its original state, it cannot enter the liquid crystal storage space 6. When the liquid crystal 8 is heated, it becomes an isotropic upper 12 phase which has a low viscosity.
A phase transition takes place, and the liquid crystal 8 enters a fluid state. Therefore, the liquid crystal 8 moves due to the gravity caused by the inclination of the angle θ provided on the base 10, and the liquid crystal 8 moves due to capillary action.
), it is injected into the liquid crystal storage space 6. In this method, defoaming from the liquid crystal 8 is mainly performed in the vacuuming process.

The isotropic phase has a low viscosity and low gas solubility due to the high temperature. Due to these synergistic effects, defoaming is performed better in the isotropic/reactive phase than in other phases. For this reason, defoaming in the evacuation process is insufficient, and the quality of the liquid crystal cell 1 may be degraded due to air bubbles remaining in the liquid crystal 8 injected into the liquid crystal cell 1.

Next, the suspension method using a liquid crystal tank will be explained. In this suspension method, the liquid crystal cell 1 is vertically suspended in the vacuum chamber 13 with the injection port 12 facing down, in the configuration of the melting method shown in FIG. Base 1 that can be raised and lowered and has a horizontal top surface
0, a hot plate 11 is placed, and a liquid crystal tank is further placed on top of the hot plate 11. The liquid crystal tank is filled with liquid crystal 8. The base 10 described above is placed in the vacuum chamber 13. At this time, the liquid crystal tank 13 is arranged below the liquid crystal cell 1, and the liquid crystal cell 1 and the liquid crystal 8 are arranged so as not to touch each other. The inside of the vacuum chamber 13 is evacuated using the vacuum source 14. Thereafter, the liquid crystal tank and the liquid crystal 8 are heated by the heater 11, and the liquid crystal 8 is heated.
is the isotropic phase. Since the isotropic phase is formed under reduced pressure, the liquid crystal 8 can be defoamed under favorable conditions.

After the defoaming is completed, the base 10 is raised and the liquid crystal cell 1 is immersed in the liquid crystal 8. As a result, the injection port 12 comes into contact with the liquid crystal 8, and the liquid crystal 8 is injected into the liquid crystal storage space 6 by capillary action. In this method, since the liquid crystal cell 1 is immersed in the liquid crystal 8, the liquid crystal 8 adheres to the liquid crystal cell 1, resulting in a large loss of the liquid crystal 8. Therefore, production efficiency decreases.

FIG. 10 is a side view of the liquid crystal injection device N15 in the dropping method. A dropping device 17 for the liquid crystal 8, a dropping tool 18, and the liquid crystal cell 1 are fixed by a pedestal 16 installed in the vacuum chamber 13. The dropping device 17 and the dropping tool 18 are provided with heating devices. At this time, the liquid crystal cell 1 is installed with the injection port 12 facing upward. The dropping tool 18 is installed at a position where the liquid crystal 8 is dropped into the injection port when the liquid crystal S is dropped. The inside of the vacuum chamber 13 is evacuated using the vacuum source 14. Next, the dropping device 17 and the dropping tool 18 are heated, and the liquid crystal 8 which has become an isotropic/reactive phase is poured into the injection port 12.
Drip into. Since the injection port 12 is not heated, the liquid crystal 8 on the injection port 12 undergoes a phase transition into a grease-like state. This closes the injection port 12. Next, the inside of the vacuum chamber 13 is returned to room temperature, but since the injection port 12 is blocked by the grease-like liquid crystal 8, the vacuum in the liquid crystal storage space 6 in the liquid crystal cell 1 is maintained. Thereafter, the liquid crystal cell 1 is stored in a heating oven with the injection port 12 facing upward. The liquid crystal 8 becomes an isotropic phase in the oven and is injected into the liquid crystal storage space 6 through the injection port 12. This method requires electrical and mechanical members for dropping the liquid crystal, making the device complicated and large. Also, once the liquid crystal 8 is returned to normal pressure, the liquid crystal 8 is injected. f. The defoaming of the liquid crystal 8 is insufficient, and the liquid crystal cell 1.
7) Quality may deteriorate.

Problems to be Solved by the Invention When injecting a highly viscous liquid crystal 8 such as a ferroelectric liquid crystal using the melting method described above, when the inside of the vacuum chamber 13 is evacuated, air bubbles generated in the liquid crystal 8 may Since the injection port 12 is blocked, the inside of the liquid crystal cell is not vacuumed, and the liquid crystal cell 1
There was a problem in that the quality of the liquid crystal cell 1 deteriorated due to the air bubbles remaining in the liquid crystal cell 1. As a means to solve this problem, precise control of the degree of vacuum and temperature is required, which leads to the problem that the apparatus becomes complicated and large. Another possibility is to degas the liquid crystal 8 under vacuum in advance.
- Since the liquid crystal 8 after degassing is exposed to normal pressure, degassing becomes insufficient, the quality of the liquid crystal cell 1 deteriorates, and the number of steps to create a vacuum twice increases. Also, in the hanging method, the liquid crystal cell 1
Since the liquid crystal 8 is immersed in the liquid crystal 8, unnecessary liquid crystal 8 adheres to the liquid crystal cell 1, resulting in a large loss of the liquid crystal S, resulting in a reduction in manufacturing efficiency. Similarly, the dropping method requires a complicated device, is large in size, is insufficient in defoaming the liquid crystal 8, and has the problems of deteriorating the quality of the liquid crystal cell 1.

An object of the present invention is to provide a manufacturing apparatus for a liquid crystal display device that has improved quality, good manufacturing efficiency, is simplified and downsized, and has simplified processes.

Means for Solving the Problems The present invention relates to a manufacturing process for manufacturing a liquid crystal display device by injecting liquid crystal into a liquid crystal element comprising a pair of transparent substrates whose peripheries are sealed in the remaining area other than the liquid crystal injection port. , a housing whose internal storage space can be switched between vacuum and normal pressure, and a liquid crystal element disposed within the storage space to store liquid crystal, deform when heated to a predetermined temperature, and disposed below. and a liquid crystal storage means for dropping liquid crystal into a liquid crystal injection port.

According to the present invention, a liquid crystal element having an injection port is provided in a housing whose internal storage space can be switched between vacuum and normal pressure;
Liquid crystal storage means is disposed for storing liquid crystal, deforming it when heated to a predetermined temperature, and dropping the liquid crystal into a liquid crystal injection port of a liquid crystal element disposed below. The inside of the housing is evacuated and the liquid crystal inside the storage means is foamed. after that,
By heating, the liquid crystal becomes a low-viscosity fluid and is further foamed. Furthermore, by heating, the liquid crystal storage means is deformed, and the liquid crystal is dripped into the injection port of the liquid crystal element.

The dropped liquid crystal is injected into the liquid crystal element from the injection port. When the liquid crystal foams, since the liquid crystal and the injection port are separated, the injection port will not be blocked by air bubbles, and there is no possibility that air bubbles will remain in the liquid crystal element. Furthermore, since the liquid crystal is degassed in a low viscosity fluid state, there is no fear that air bubbles will remain in the liquid crystal. Therefore, since there are no air bubbles in the liquid crystal element injected with liquid crystal, it is possible to improve the quality of the liquid crystal element. Furthermore, by using a storage means that deforms when heated to a predetermined temperature, f! f: Since a certain rectangular amount of liquid crystal is dropped, the loss of liquid crystal is reduced and the manufacturing efficiency is improved compared to the known structure in which the vicinity of the end of the liquid crystal element on the injection port side is immersed in the liquid crystal. In addition, since no complicated control is required, the device can be made smaller and the process can be simplified.

Embodiment FIG. 1 shows a liquid crystal cell 21 under manufacture according to an embodiment of the present invention.
FIG. 2 is a sectional view of the embodiment shown in FIG. A band-shaped transparent electrode 1 is placed on a pair of transparent glass substrates 22 and 23, respectively.
24a and 24b are arranged, and an alignment film 25 is further disposed thereon.
a, 25b are formed. A pair of substrates 22. ') 3 are faced to each other so that the electric fii 24a 24b are perpendicular to each other, and are bonded together with a sealing material 26 so that a liquid crystal injection port 27 and a liquid crystal storage space 28 are formed.

The protruding portion 22a of the substrate 22 that protrudes from the substrate 23 serves as a dropping position 29 for the liquid crystal, which will be described later.

FIG. 3 is a side view of an embodiment of the present invention, and FIG. 4 is a side view of an embodiment of the present invention.
FIG. 3 is a side view of the embodiment shown in the figure at the time of liquid crystal injection. The angle θ (preferably 10° to 30°) of the upper surface with respect to the horizontal plane
An unfinished liquid crystal cell 21 is placed on a base 30 that is inclined by a certain amount. A container 33 is fixed to the side surface of the vacuum chamber 31 with a support rod 32 made of a shape memory alloy. The support rod 32 is heated at a temperature higher than the reverse transformation temperature of the martensitic phase to the parent phase I\,
It is molded into the shape shown in FIG. 4, and then deformed by applying stress to the shape shown in FIG. 3 at a temperature below the transformation temperature from the parent phase to the martensitic phase.

The reverse transformation temperature of the support rod 32 is set to be higher than the temperature at which the liquid crystal 34 injected into the liquid crystal cell 21 becomes an isotropic phase. The liquid crystal 34 is filled in the container 11. The vacuum chamber 31 is connected to a vacuum source 35 and has an infrared lamp 36 inside.
is installed. The base 30 is housed in a vacuum chamber 31. At this time, the two dropping positions are container 3 in FIG.
The liquid crystal 34 is placed at the position where the liquid crystal 34 is dropped from step 3.

No. 5 [1i11] is a process diagram of a specific example of the embodiment of the present invention. The material of the support rod 32 is Ti-Ni.
An alloy (composition: Ti-50N1 (at%)) is used. The support rod 32 is formed into the shape shown in FIG. 4 at a temperature higher than 78° C., which is the reverse transformation g temperature from the martensitic phase to the matrix phase, and then at the transformation temperature from the matrix phase to the martensitic phase. At a temperature lower than 60° C., stress is applied and deformed to the shape shown in FIG. As the liquid crystal 34, a ferroelectric liquid crystal (manufactured by Teikoku Kagaku Co., Ltd.: TKF-8616) is used. This liquid crystal 34 has a smectic C phase-(52
℃) - smectic A phase - (64℃) isotropic phase.

In step a1, liquid crystal 34 is placed in container 33.

The amount of liquid crystal 34 at this time is, for example, near the injection port 27 or in the container 3 relative to the volume of the liquid crystal storage space 28 of the liquid crystal cell 21.
Taking into account losses such as adhesion to the inner wall of No. 3, it is set at 120%. In step a2, the liquid crystal cell 21 is installed on the base 30, and the base 3O is housed in the vacuum chamber 31 in step a3.

In step a4, the pressure inside the vacuum chamber 31 is 2.10-'
It is evacuated until it reaches torr. In this process, air bubbles are generated from the liquid crystal 34 in the container 33, but since the liquid crystal cell 21 is far away, the air bubbles do not block the injection port 27, and the inside of the liquid crystal cell 21 is kept in a sufficient vacuum state. I can do it. In step a5, the infrared lamp 36 is turned on and the temperature inside the vacuum chamber 31 is raised to 65°C. Step a6
In this case, the inside of the vacuum chamber 31 is maintained at 65°C. In step a6, the liquid crystal 34 becomes an isotropic phase.

Since the temperature is maintained at 65° C., the liquid crystal 34 can be defoamed in an isotropic phase, which is preferable for defoaming, and all the bubbles in the liquid crystal 34 can be removed.

In step a7, an infrared lamp 36 is installed inside the vacuum chamber 31.
The temperature is further raised to 85°C, and maintained at 85°C in step a8. At 85° C., the support rod 32 reversely transforms from the martensite phase to the parent phase, and assumes the shape shown in FIG. Therefore, the liquid crystal 34 is dropped onto the drop position 29 on the liquid crystal cell 21, and the liquid crystal 34 is moved from the injection port 27/
It is injected into the liquid crystal storage space 28 by flow and capillary action. In step a9, the inside of the vacuum chamber 31 is returned to normal temperature and pressure. At this time, there is no risk of air bubbles entering the liquid crystal 34 injected into the liquid crystal cell 21. In step a8,
In step a9, the support rod 32 showing the shape of the matrix is
When the temperature inside the vacuum chamber 31 becomes lower than 60° C., which is the transformation temperature from the EJ: phase to the martensitic phase, the shape returns to that shown in FIG. 3. In step alo, the liquid crystal cell 21 is taken out from the vacuum chamber 31. The injection port 27 is sealed with an acrylic ultraviolet curing resin, and the liquid crystal cell 21 is completed.

A Ti-Ni-Cu alloy (composition: Ti-20Ni-30Cu (at%)) is used as the material for the support rod 32, and a ferroelectric liquid crystal (manufactured by Merck & Co., Ltd.: ZLI-42) is used as the liquid crystal 34.
37-000) is used. At this time, the reverse transformation temperature of the support rod 32 is 85°C, and the transformation temperature is 80°C. The support rod 32 is subjected to the same treatment as in the above specific example, depending on the reverse transformation temperature and the transformation temperature. The phase series of the liquid crystal 34 is smectic C phase - (63°C) - smectic A phase -
(72°C) - nematic phase - (79°C) - isotropic phase.

In this specific example as well, the liquid crystal cell 21 is completed in the same steps as shown in FIG. 5, but the temperature in steps a5 and a6 is 80°C, and the temperature in steps a7 and a8 is 95°C. becomes. In this specific example as well, the same results as in the above specific example can be obtained.

When changing the liquid crystal 34, the support rod 32 may be made of an alloy having a reverse transformation temperature higher than the temperature at which the liquid crystal 34 undergoes a phase transition to an isotropic phase. The temperature from step a5 to step a8 is determined by the materials of the liquid crystal 34 and the support rod 32.

In the present invention, precise control members are not required and the device is simple and compact. The interior of the liquid crystal cell 21 has been sufficiently evacuated and the liquid crystal 34 has been degassed, and the completed liquid crystal cell 21
There is no risk of air bubbles being trapped inside, which improves the quality of the product. Since a certain amount of liquid crystal 34 is dropped according to the liquid crystal storage space 28, there is less loss of liquid crystal 34, as pointed out in the explanation regarding the conventional hanging method, and manufacturing efficiency is improved. Furthermore, since the liquid crystal 34 is dropped by utilizing the temperature-induced transformation of the shape memory alloy, a complicated device is not required, the device is small, and the process is simplified.

FIG. 6 is a side view of a liquid crystal dropping means according to another embodiment of the present invention, and FIG. 7 is a side view of the embodiment shown in FIG. 6 during liquid crystal dropping. This embodiment is a modification of the dripping means in the injection device of the previous embodiment. A handle 37 is attached to the container 33, and the container 33 is suspended from the upper surface of the vacuum chamber 31 using a hanging metal 38. A shape memory alloy spring 32a is fixed to the bottom of the container 33, and the other spring 32a is fixed to the top of the vacuum chamber 31. The spring 32a is formed into the shape shown in FIG. 7 at a temperature higher than the reverse transformation temperature from the martensitic phase to the matrix phase, and then molded into the shape shown in FIG. 6 at a temperature lower than the transformation temperature from the matrix phase to the martensitic phase. It is deformed by applying stress to the shape. Even when such a dropping means is used, the same effects as in the above embodiment can be obtained.

Further, even when the container body is made of a shape memory alloy and dropping is performed by changing the shape of the container body, the same effects as in the above-mentioned embodiments can be obtained. The temperature inside the vacuum chamber 31 is increased,
The same applies when a pot plate placed between the liquid crystal cell 21 and the base 30 is used in addition to the infrared lamp 36, or when the liquid crystal cell 21 is stood up by some means with the injection port 27 facing upward. The effect of this can be obtained.

As described above, according to this embodiment, the quality of the liquid crystal cell 21 is improved, the manufacturing efficiency is improved, the device is simplified and the device is downsized, and the process can be simplified.

Effects of the Invention According to the present invention, there is provided a liquid crystal element having an injection port in a housing whose internal storage space can be switched between vacuum and normal pressure;
A liquid crystal storage means is disposed in which liquid crystal is stored, deforms when heated to a predetermined temperature, and drops the liquid crystal into the liquid crystal injection ports of the liquid crystal elements arranged above and below. The inside of the housing is evacuated and the liquid crystal inside the storage means is foamed. after that,
By heating, the liquid crystal becomes a low-viscosity fluid and is further foamed. Furthermore, the liquid crystal storage means is deformed by heating, and the liquid crystal is dripped into the injection port of the liquid crystal element. The dropped liquid crystal is injected into the liquid crystal element from the injection port. When the liquid crystal foams, since the liquid crystal and the injection port are separated, the injection port will not be blocked by air bubbles, and there is no risk of air bubbles remaining in the liquid crystal element. Furthermore, since the liquid crystal is degassed in a low viscosity fluid state, there is no fear that air bubbles will remain in the liquid crystal. Therefore, since no air bubbles are present in the liquid crystal element into which the liquid crystal is injected, the quality of the liquid crystal element can be improved. In addition, we use a storage means that deforms when heated to a predetermined temperature to accommodate the liquid crystal storage space.
Compared to the well-known configuration in which the vicinity of the end of the liquid crystal element on the injection port side is immersed in the liquid crystal in order to drop a certain amount of liquid crystal,
There is less liquid crystal loss, which improves manufacturing efficiency. Further, since no complicated control is required, the device can be simplified and made smaller, and the process can be further simplified.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a liquid crystal cell 21 during manufacture used in the present invention, and FIG. 2 is a plan view of the liquid crystal cell 21 shown in FIG. 1.
3 is a side view of the embodiment of the present invention, FIG. 4 is a side view of the embodiment shown in FIG. 3 at the time of liquid crystal injection, and FIG. 6 is a side view of another embodiment of the present invention; FIG. 7 is a side view of the embodiment shown in FIG. 6 during liquid crystal injection; FIG. 8 is a process diagram of liquid crystal cell injection using the present invention. is a cross-sectional view of the liquid crystal cell 1 during manufacture used in the conventional example, and FIG. 9 is a side view of the conventional example.
FIG. 10 is another side view of the conventional example. 21 ・Liquid crystal cell, 22. 23... Substrate, 26...
Seal material, 27... Inlet, 31... Vacuum chamber, 32...
...Support rod, 33...Container, 34...Liquid crystal/ Fig. 1 5a 4a 22 Fig. 2 Fig. 1o Fig.

Claims (1)

[Scope of Claims] In the manufacturing process of manufacturing a liquid crystal display device by injecting liquid crystal into a liquid crystal element having a pair of transparent substrates whose peripheries are sealed except for the liquid crystal injection port, an internal storage space is used. of,
A housing that can be switched between vacuum and normal pressure, and a housing that is placed in the storage space to store liquid crystal, deforms when heated to a predetermined temperature, and pours the liquid crystal into the liquid crystal injection port of the liquid crystal element placed below. 1. An apparatus for manufacturing a liquid crystal display device, comprising: storage means for dropping liquid crystal.