JPH03154028A - Manufacture of liquid crystal panel - Google Patents

Abstract

PURPOSE:To completely fill the inside of a panel with a smectic liquid crystal without generating bubbles by filling a liquid crystal by enlarging gradually a heating area for heating a liquid crystal panel from an injection port end. CONSTITUTION:At the time of filling the inside of a liquid crystal panel 1 with a smectic liquid crystal, it is constituted so that an empty panel 1 is held at a temperature lower than a temperature at which the liquid crystal makes phase transition from the smectic phase and exhibits fluidity, and also, set to a state that the liquid crystal is brought into contact with at least one of at least two injection port parts 2 provided on the panel, and thereafter, the panel temperature of the vicinity of the injection port part brought into contact with the liquid crystal is set to a higher temperature than a transition temperature, and subsequently, the smectic liquid crystal is led into the panel by enlarging gradually the high temperature area. According to the constitution, since the high temperature area of the panel is enlarged gradually from the injection port part side brought into contact with the liquid crystal, the inside of the panel is filled enough with the smectic liquid crystal without generating bubbles.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a liquid crystal panel used for displaying images, etc. Specifically, the present invention relates to a method for manufacturing a liquid crystal panel used for displaying images, etc. The present invention relates to a method of manufacturing a liquid crystal panel in which a narrow temperature transition region is provided and the liquid crystal panel is filled with liquid crystal by expanding the region.

[Prior Art] A vacuum injection method for nematic liquid crystal is conventionally known as a method for injecting liquid crystal into a liquid crystal panel. The method is to reduce the pressure inside the liquid crystal panel and then return the pressure to normal pressure with the injection port covered with nematic liquid crystal, thereby injecting nematic liquid crystal into the liquid crystal panel.

Furthermore, since smectic liquid crystals do not have fluidity at room temperature, a proposed method for injecting such liquid crystals into liquid crystal panels is to heat the liquid crystals to an isotropic state and then inject them under vacuum. (Unexamined Japanese Patent Publication No. 61-35
429, etc.).

[Problems to be Solved by the Invention] However, in the conventionally known general method as described above, the liquid crystal panel is not sufficiently filled with liquid crystal, and as a result, a large number of air bubbles remain in the liquid crystal panel. There was a problem. Furthermore, conventional methods always require a vacuum device, making it essential to reduce the pressure inside the liquid crystal panel. Therefore, a large amount of cost is required for the liquid crystal filling process, leading to an increase in manufacturing costs. Furthermore, in the case of the conventional method, the vacuum equipment itself used is large, so a large manufacturing space is required.

In view of the problems of the prior art as described above, an object of the present invention is to
In a method for manufacturing a liquid crystal panel, it is an object of the present invention to more easily fill a liquid crystal panel with a sufficient amount of smectic liquid crystal.

[Means for Solving the Problem] As a result of intensive research, the present inventors have found that the above object can be solved by gradually expanding the heating area of the liquid crystal panel from the injection port. We have arrived at the heading Invention.

That is, in the method for manufacturing a liquid crystal panel of the present invention,
When filling a liquid crystal panel with smectic liquid crystal, the empty liquid crystal panel is held at a temperature lower than the temperature at which the liquid crystal undergoes a phase transition from the smectic phase and becomes fluid, and at least two liquid crystal panels are provided in the liquid crystal panel. After bringing the liquid crystal into contact with at least one of the injection ports, the temperature of the liquid crystal panel in the vicinity of the injection port in contact with the liquid crystal is raised to a temperature higher than the transition temperature, and then this high temperature region is gradually increased. The smectic liquid crystal is introduced into the liquid crystal panel by enlarging the liquid crystal.

[Function] In this configuration, the smectic liquid crystal undergoes a phase transition from the smectic phase, preferably becomes an isotropic state, and has increased fluidity, and is introduced into the high temperature region of the liquid crystal panel from the injection port. Since the high-temperature region of the liquid crystal panel is gradually expanded from the side of the injection port that is in contact with the liquid crystal, the smectic liquid crystal is sufficiently filled into the liquid crystal panel without forming bubbles.

[Example] Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a cross-sectional view of a liquid crystal panel filled with liquid crystal, and this liquid crystal panel 1 has a seal shape with an injection port 2 having a width of 80 mm at both ends, and a seal portion 3 having a width of 4 mm.
It is a liquid crystal panel with inner seal dimensions of 122 mm in length and 222 mm in width, and a panel gap of 1.4 μm. At the same time as a gap agent for maintaining the gap, small adhesive particles are also sprayed into the liquid crystal panel 1 to adhere the inside of the liquid crystal panel.

Further, as the liquid crystal filled in the liquid crystal panel 1, a conductive smectic liquid crystal (manufactured by Chisso Corporation, product number: CS-1014) having the following transition temperature was used.

-21℃ 54.4℃ 69.5℃ 80.9℃
(Cry: crystalline phase, Sc": chiral smectic C
phase, SA: smectic A phase, Ch: cholesteric phase, I8°: isometric phase) Figure 2 is a schematic diagram showing an example of an apparatus for filling a liquid crystal panel with liquid crystal, and in the figure, 4 indicates the liquid crystal panel. 5 is a device for cooling circulating water; 6 is a constant temperature bath for heating the water;
is a pump for circulating cooling water, 7 is a lifting device that lifts up the panel holding jig, 8 is a thermometer, 9 is a water tank for cooling the panel holding jig, 10 is a panel holding jig, and 11 is a liquid crystal holder. It is.

In order to fill the liquid crystal panel 1 with liquid crystal using this device, first load the empty liquid crystal panel 1 into the liquid crystal holder, connect the upper injection port 2 to the liquid crystal holder 11, and then fill the liquid crystal panel 1 with liquid crystal.
The whole was submerged in cooling water in a water tank 9, and the temperature inside the constant temperature bath was maintained at 95°C and the temperature of the cooling water was maintained at 15°C.

Next, the speed of the elevator 7 is set to 0. 2 mm/min, slowly pull up the liquid crystal panel 1 from the cooling water, gradually expand the high temperature area of the liquid crystal panel 1 from the injection port 2 side connected to the liquid crystal holder 11, and finally the liquid crystal The entire panel 1 was lifted out of the cooling water.

As a result, the liquid crystal panel 1 was sufficiently filled with liquid crystal without any gaps. No air bubbles were observed in the liquid crystal panel filled with liquid crystal in this manner, confirming the effect of liquid crystal injection by the manufacturing method of the present invention.

[Other Embodiments] In the first embodiment described above, a water tank was used to cool the liquid crystal panel, but the same effect can be obtained even if the liquid crystal panel itself is cooled by other cooling means.

FIG. 3 is a schematic diagram showing another example of an apparatus for filling a liquid crystal panel with liquid crystal, in which 12 is a constant temperature bath;
3 is a gate valve for controlling cooling air; 14 is a liquid crystal plate for supplying liquid crystal to the panel; 15 is a heater for heating the liquid crystal plate; 16 is a circulating air cooling device; 17 is a pump for circulating air; 18 is a temperature control unit. A total of 19 designates flat cooling pipes that are in close contact with the front and back surfaces of the panels and pass cooling air through them.

In order to fill the liquid crystal panel 1 with liquid crystal using this device, first, the empty liquid crystal panel 1 was set on the liquid crystal dish 14 in the constant temperature bath 12, and the lower injection port 2 was connected to the liquid crystal dish 14. . Next, all the gate valves 13 are opened, and while the entire liquid crystal panel 1 is cooled to a temperature at which the liquid crystal maintains the smectic phase, the inside of the constant temperature bath 12 is maintained at 95° C., and the liquid crystal in the liquid crystal dish 14 is kept cooled. It was also heated. After this state was maintained for 2 hours, the lowermost gate valve 13 was closed and the lowermost portion of the liquid crystal panel 1 was heated. Subsequently, the gate valves on the lower side were sequentially closed one by one every two hours, and finally the entire liquid crystal panel 1 was heated.

As a result, as in Example 1, the liquid crystal panel 1 was sufficiently filled with liquid crystal without any gaps. No air bubbles were observed in the liquid crystal panel filled with liquid crystal using the above method, confirming once again the effect of liquid crystal injection using the manufacturing method of the present invention.

[Effects of the Invention] As explained above, according to the manufacturing method of the present invention, the heating region for heating the liquid crystal panel is gradually expanded from the injection port end to fill the smectic liquid crystal. It is possible to completely fill a liquid crystal panel with smectic liquid crystal without creating bubbles.

Further, according to the manufacturing method of the present invention, there is no need to reduce the pressure inside the liquid crystal panel when filling the liquid crystal, the conventional pressure reduction step is omitted, and a pressure reduction device is not required. Therefore, manufacturing costs can be reduced and a large manufacturing space is not required. Further, according to the manufacturing method of the present invention, the manufacturing tact of the liquid crystal injection process is improved, and the manufacturing yield is also increased.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a liquid crystal panel filled with liquid crystal by a method according to an embodiment of the present invention, and FIG. 2 is a liquid crystal injection device used to carry out a method according to an embodiment of the present invention. FIG. 3 is a schematic diagram showing a liquid crystal injection device used to carry out a method according to another embodiment of the present invention. 1: Liquid crystal panel, 2: Inlet, 3: Seal part, 4: Constant temperature chamber, 5: Circulating water cooling device, 6: Cooling water circulation pump, 7: Panel holding jig lifting device, 8: Thermometer, 9: water tank, 10: panel holding jig, 11: liquid crystal holder, 12: constant temperature bath, 13: gate valve for cooling air adjustment, 14: night crystal dish, 15: heater for heating liquid crystal dish, 16: circulating air cooling device, 17: Cooling air circulation pump, 18: Thermometer, 19: Flat cooling pipe.

Claims (1)

[Claims] When filling a liquid crystal panel with smectic liquid crystal, the empty liquid crystal panel is held at a temperature lower than the temperature at which the liquid crystal undergoes a phase transition from the smectic phase and becomes fluid, and at least two liquid crystal panels are provided in the liquid crystal panel. After bringing the liquid crystal into contact with at least one of the injection ports, the temperature of the liquid crystal panel in the vicinity of the injection port in contact with the liquid crystal is raised to a temperature higher than the transition temperature, and then this high temperature region is gradually increased. A method for manufacturing a liquid crystal panel, comprising introducing the smectic liquid crystal into the liquid crystal panel by enlarging the smectic liquid crystal into the liquid crystal panel.