JP2000019541A - Method for filling liquid crystal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to suppress the generation of air bubbles within a liquid crystal panel by filling liquid crystals into the liquid crystal panel, then pressurizing the injection port of the liquid crystal panel more than in the other portions of the liquid crystal panel. SOLUTION: The display region 10 of the liquid crystal panel 1 is arranged within a vessel 4 and the liquid crystal injection port 9 of the liquid crystal panel 1 is arranged within a pressurized vessel 3. The end inclusive of the injection port 9 of the liquid crystal panel 1 is arranged in the pressurized vessel 3 through the opening of the pressurized vessel 3. The airtightness between the opening and the liquid crystal panel 1 is held by an annular gasket 7. More specifically, the substrates laminated with transparent electrodes, insulating films, etc., are fixed to each other, by which the liquid crystal panel 1 is formed. Next, the liquid crystals are injected into the injection port 9 of the liquid crystal panel 1. After the inside of the pressurized vessel 3 and the vessel 4 are set at prescribed temp., gaseous nitrogen increased to a prescribed pressure is introduced into the pressurized vessel 3 from its introducing part 5 and gas of the pressure lower than the pressure of the pressurizing gas of the introducing part 5 is introduced into the vessel 4 from its introducing part 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal injection method.

[0002]

2. Description of the Related Art Conventionally, when a liquid crystal exhibiting a gel-like property at a temperature lower than the isotropic phase temperature, such as a smectic liquid crystal, is injected into a liquid crystal panel, the liquid crystal is in an isotropic liquid state. . For this reason, after the liquid crystal is injected into the liquid crystal panel, the volume of the liquid crystal panel shrinks at the time of phase transition in a process of cooling to room temperature, which causes a problem that a gap is generated in the liquid crystal panel.

As a method for solving such a problem, there is a method described in Japanese Patent Laid-Open Publication No. Hei 6-51258. In this method, after injecting liquid crystal into the liquid crystal panel, the entire liquid crystal panel is pressurized, then returned to the atmospheric pressure, and the liquid crystal panel is cooled to room temperature.

[0004]

However, in the above-mentioned conventional method, the liquid crystal is filled in the liquid crystal panel in a state where the entire liquid crystal panel is pressurized. In the state returned to the above, the following problem occurs. That is, in a state where the pressure applied to the liquid crystal panel is released and the pressure is returned to the atmospheric pressure, the liquid crystal panel tends to return to the volume at the time of the atmospheric pressure according to the elastic modulus.
At this time, in the case of a gel-like and highly viscous liquid crystal such as a smectic liquid crystal, the liquid crystal applied to the injection port of the liquid crystal panel is not quickly supplied into the liquid crystal panel, and the filling density of the liquid crystal in the liquid crystal panel is reduced. The inside of the liquid crystal panel is in a negative pressure state.
As a result, the presence of a negative pressure in the liquid crystal panel generates bubbles dissolved in the liquid crystal. When the liquid crystal panel is stored in a low temperature state, the liquid crystal in the liquid crystal contracts in volume, but if the liquid crystal panel does not follow or does not follow the contraction, a negative pressure is generated in the liquid crystal panel. Since the negative pressure is more likely to occur when the filling density of the liquid crystal in the liquid crystal panel is low, bubbles are generated in the liquid crystal panel even in the above-described conventional low-temperature storage.

The present invention aims to suppress the generation of air bubbles in a liquid crystal panel by providing a method for increasing the packing density of liquid crystal in a liquid crystal panel.

[0006]

According to the first aspect of the present invention, after injecting liquid crystal into the liquid crystal panel, the injection port of the liquid crystal panel is pressurized in comparison with other portions of the liquid crystal panel. In addition, a pressure difference is applied to the inside of the liquid crystal panel to forcibly fill the liquid crystal panel with liquid crystal present at the injection port. For this reason, the filling density of the liquid crystal in the liquid crystal panel is improved, and the generation of bubbles after the completion of the liquid crystal panel or the generation of bubbles when the liquid crystal panel is stored at a low temperature can be suppressed.

According to the invention described in claim 2, according to claim 1
In carrying out the method described in the above, by pressing the injection port portion of the liquid crystal panel using a pressurized gas in a state in which the injection port of the liquid crystal panel is covered with a gas barrier film, the liquid crystal by the pressurized gas The pressurization of the inlet portion of the panel can be carried out strongly, the same operation and effect as the invention of claim 1 can be obtained, and the use of the pressurized gas allows the gas to flow into the liquid crystal panel through the inlet. Can be avoided.

According to the invention described in claim 3, according to claim 1
The same operation and effect as the operation and effect of the invention can be obtained. According to the fourth aspect of the invention, the liquid crystal is easily filled by pressurization.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) Hereinafter, a first embodiment of the present invention will be described. 1 to 3,
1 is a cross-sectional view showing a manufacturing apparatus, FIG. 2 is a plan view of a liquid crystal panel, and FIG. 3 is a process diagram showing a manufacturing process of the liquid crystal panel.

In FIG. 1, a display area 1 of a liquid crystal panel 1 is shown.
Numeral 0 is arranged in the container 4, and the liquid crystal injection port 9 of the liquid crystal panel 1 is arranged in the pressurized container 3. That is, although not shown, the container 4 has an electric heater disposed therein and has an opening at an end thereof. The pressurized container 3 is arranged in the container 4 through the opening, and airtightness is maintained between the opening of the container 4 and the partition wall of the pressurized container 3 via a ring-shaped gasket 8.

An end of the liquid crystal panel 1 including the inlet 9 is disposed in the pressure vessel 3 through an opening of the pressure vessel 3, and a space between the opening and the liquid crystal panel 1 is formed by a ring-shaped gasket 7. Airtightness is maintained. An introduction unit 5 for introducing a pressurized gas (nitrogen gas) into the pressurized container 3
The container 4 is provided with an introduction section 6 for introducing a gas for depressurizing the inside of the container 4.

The liquid crystal panel 1 has a configuration as shown in FIG. The substrate 11 and the substrate 12 are superposed, and the liquid crystal panel 1 is composed of a seal 14 disposed between the substrates 11 and 12 and a plurality of partitions 13 for maintaining a constant gap between the substrates 11 and 12. Have been. In the figure, reference numeral 15 denotes a liquid crystal, which is formed of a semi-ferroelectric liquid crystal in the present embodiment.

Next, a method for manufacturing a liquid crystal panel and a method for pressing the liquid crystal panel according to the present invention will be described. First,
A method for manufacturing a liquid crystal panel filled with liquid crystal by the process shown in FIG. 3 will be described. That is, in FIG.
In this method, a color filter, a transparent electrode, an insulating film, and an alignment film are sequentially laminated and formed by a known method, and then the surface of the alignment film is subjected to a uniaxial alignment process, that is, a rubbing process. After this rubbing treatment, a sealing material is applied to the outer periphery of the substrate 11 in a U-shape as shown in FIG.

On the other hand, a transparent electrode, an insulating film, and an alignment film are sequentially laminated and formed on the substrate 12 in a direction intersecting the transparent electrodes of the substrate 11 in a matrix manner by a known method.
Next, as shown in FIG. 2, a plurality of known stripe-shaped partition walls are formed on the alignment film by exposure and development using a photocurable resin. Subsequently, the surface of the alignment film including the partition walls is subjected to a uniaxial alignment treatment, that is, a rubbing treatment.

After the films and the like are formed on the surfaces of the substrates 11 and 12 as described above, the substrates 11 and 12 are overlapped so that the electrodes intersect in a matrix. Next, the substrate 11 and the substrate 12 are fixed to each other by a step of curing the sealing material and the partition walls, thereby producing a so-called empty liquid crystal panel. Liquid crystal is injected into the injection port of the empty liquid crystal panel by a known method.
That is, an empty liquid crystal panel is placed in a pressure vessel, the inside of the pressure vessel is set at a predetermined temperature, and the inside of the vessel is depressurized to a predetermined pressure. Next, a gel antiferroelectric liquid crystal is applied to the injection port of the empty liquid crystal panel. The application amount is about twice the volume of the empty liquid crystal panel.

While the inside of the pressure vessel is maintained at a predetermined temperature, the inside of the vessel is returned to the atmospheric pressure. As a result, the liquid crystal in the isotropic liquid state due to the temperature setting in the pressure vessel advances into the liquid crystal panel due to the pressure difference between the liquid crystal panel and the pressure vessel. After a predetermined time, the temperature in the pressure vessel is lowered and cooled to room temperature. Next, the liquid crystal panel filled with the liquid crystal by such a method is arranged in the pressurized container 3 of FIG. That is, the panel 1 including the injection port 9 of the liquid crystal panel 1
Of the liquid crystal panel 1 and a display portion of the liquid crystal panel 1 in the container 4.

In this state, in order to reduce the viscosity of the liquid crystal already filled in the liquid crystal panel 1 and the liquid crystal remaining in the injection port 9 of the liquid crystal panel 1, the liquid crystal is not arranged in the containers 3 and 4 (not shown). Electricity is supplied to the electric heater to set and maintain the inside of the containers 3 and 4 at a predetermined temperature. Next, nitrogen gas, which has been increased to a predetermined pressure, is introduced from the introduction section 5 of the container 3. On the other hand, a gas set at a lower pressure than the pressurized gas in the introduction section 5 is introduced from the introduction section 6 of the container 4.

As a result, since the pressure in the container 3 is higher than that in the container 4, the liquid crystal remaining in the inlet of the liquid crystal panel 1 is pressed, and the liquid crystal panel 1 located in the low-pressure container 4 is pressed. The display region 10 is filled with the liquid crystal from the injection port 9, and the filling density of the liquid crystal in the liquid crystal panel 1 is improved. In this way, after increasing the filling density of the liquid crystal, the power supply to the electric heaters in the containers 3 and 4 is stopped while maintaining the pressure in the containers 3 and 4 to reduce the temperature in the containers 3 and 4 to room temperature. Down to After cooling to room temperature, the pressure in the containers 3 and 4 is returned to the atmospheric pressure, the liquid crystal panel 1 is carried out of the containers 3 and 4, and the inlet 9 of the liquid crystal panel 1 is sealed by a known method.

According to the above-mentioned method, the liquid crystal is filled up to the end opposite to the injection port 9, so that no unfilled region of the liquid crystal is generated. Further, as described above, the liquid crystal panel is cooled to room temperature after pressurizing the liquid crystal injection port 9, and the generation of bubbles with the liquid crystal unfilled portion as a nucleus caused by the volume contraction of the liquid crystal during the cooling is not caused. Does not occur. (Second Embodiment) FIG.
And FIG. 5 show a second embodiment. This embodiment will be described. In this embodiment, the liquid crystal panel 1
Is different from the above-described first embodiment in that the portion of the inlet 9 is covered with a gas barrier film 16 and then the portion of the inlet 9 is pressed and the film 16 is removed after the pressing step.

As the gas barrier film 16, for example, a gas permeability coefficient of 0.5 cc / .24hour / 1a
It is composed of a vinylidene chloride-based film having tm / 20 ° C. According to this embodiment, the gas barrier film blocks the liquid crystal at the inlet 9 and the pressurized gas, so that the pressurized gas dissolves in the liquid crystal applied to the inlet 9. Can be avoided. As a result, it is possible to suppress the generation of bubbles, which are generated when the liquid crystal panel is stored in a low-temperature state and are nucleated by the gas dissolved in the liquid crystal.

In the above embodiment, the introduction section 6 of the container 4 is used.
Although low-pressure gas is introduced from the beginning, the internal gas may be evacuated from the introduction section 6. Also, as a liquid crystal,
In addition to the semi-ferroelectric liquid crystal, a low-viscosity liquid crystal such as a ferroelectric liquid crystal can be used.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a manufacturing apparatus according to a first embodiment of the present invention.

FIG. 2 is a perspective plan view of the liquid crystal panel used in the first embodiment.

FIG. 3 is a process chart showing a manufacturing process of the liquid crystal panel of the first embodiment.

FIG. 4 is a schematic sectional view showing a manufacturing apparatus according to a second embodiment of the present invention.

FIG. 5 is a process chart showing a manufacturing process of the liquid crystal panel of the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal panel 2 Liquid crystal 3 Pressurized container 4 Container 9 Injection port 10 Display area 16 Gas barrier film

Claims (4)

[Claims] 1. A method of injecting liquid crystal into a liquid crystal panel, wherein the liquid crystal is injected into the liquid crystal panel from an injection port of the liquid crystal panel, and the injection port portion of the liquid crystal panel is connected to another portion of the liquid crystal panel. A method for injecting liquid crystal, characterized by applying pressure as compared with the method described above. 2. The injection port is covered with a gas barrier film, and the injection port portion of the liquid crystal panel is pressurized by using a pressurized gas while covering the injection port with the film. The method for injecting liquid crystal according to claim 1, wherein 3. The liquid crystal injection method according to claim 1, wherein the other portion of the liquid crystal panel is a display area of the liquid crystal panel located on a side opposite to the injection port. 4. The liquid crystal panel according to claim 1, wherein the liquid crystal panel is maintained at a predetermined temperature to reduce the viscosity of the liquid crystal in the liquid crystal panel prior to pressurizing the injection port portion of the liquid crystal panel. 3. The method for injecting liquid crystal according to any one of 3.