JPH08234188A - Production of liquid crystal display device - Google Patents

Abstract

PURPOSE: To shorten the time of pressure reducing, heating and holding prior to liquid crystal injection in a cell state and to suppress cell deformation by previously subjecting a color filter substrate alone to a reduced pressure heat treatment prior to assembling a cell, then executing degassing of color filters. CONSTITUTION: The color filter substrate 4 is formed by successively forming the color filters 12, a protective film 13, transparent electrodes 14 and an insulating film 15 on the glass substrate 11. This color filter substrate 4 is arranged in a vacuum chamber in order to subject the substrate to the degassing treatment. After the pressure in the chamber is reduced, the color filter substrate 4 is heated and is held under the reduced pressure heating conditions and thereafter, the vacuum chamber is opened. An oriented film control film and sealing materials 19 are then formed on the substrate 4. On the other hand, transparent electrodes (not shown), an insulating film 15a and an orientation control film 16a are successively formed on the opposite glass substrate 11a and thereafter, spacers 18 and adhesive particulates 7 are sprayed thereon. This substrate and the color filter substrate 4 are superposed on each other and are adhered to form an empty cell (the cell into which liquid crystals are not injected).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a liquid crystal display device, and in particular, by performing a vacuum heat treatment on a color filter substrate before cell assembly, the vacuum holding time during liquid crystal injection is shortened and residual bubbles in the cell are generated. The present invention relates to a method for manufacturing a liquid crystal display device having a color filter that enables prevention.

[0002]

2. Description of the Related Art In a liquid crystal display device having a color filter, gas is easily generated from the color filter under reduced pressure. Particularly, in the case of a ferroelectric or antiferroelectric liquid crystal, it is necessary to heat the cell at the time of injecting the liquid crystal, so that the above gas generation becomes more remarkable.

In the liquid crystal injection of a liquid crystal display device having such a color filter, when gas is generated from the color filter, residual bubbles are generated in the cell after the liquid crystal is injected, which is fatal for the liquid crystal display device. It becomes a defect.

Therefore, as disclosed in Japanese Unexamined Patent Publication No. 4-42129, the gas from the color filter is removed by holding the cell under reduced pressure heating conditions for a long time before injecting the liquid crystal to inject the liquid crystal. The method of preventing the residual air bubbles afterwards is conventionally performed.

[0005]

However, in this case, the depressurization heating and holding time before injecting the liquid crystal becomes remarkably long, and the cell deformation due to the pressure difference between the inside and outside of the cell during the depressurization process and the heating stress, that is, the cell gap is disturbed. There's a problem.

Particularly, in the liquid crystal display device in which the adhesive fine particles are dispersed inside the cell, the adhesive fine particles may be peeled off due to the cell deformation. Therefore, the present invention has been made in view of the above point, and the color filter substrate is preliminarily subjected to a reduced pressure heat treatment prior to cell assembly, and degassing of the color filter is performed to thereby obtain a liquid crystal in a cell state. To provide a method for manufacturing a liquid crystal display device capable of shortening a holding time under reduced pressure before injection, suppressing a cell deformation accompanying it, and preventing generation of residual bubbles in a cell after liquid crystal injection. It is an object.

[0007]

According to the present invention, in order to solve the above problems, in a method of manufacturing a liquid crystal display device in which a color filter substrate and a counter substrate are made into cells, the color filter substrate is not assembled into cells. A method for manufacturing a liquid crystal display device is provided, which further comprises a step of subjecting a single unit to heat treatment under reduced pressure.

According to the present invention, the liquid crystal display device is characterized in that the heating temperature in the step of heat-treating the color filter substrate under reduced pressure is higher than the temperature for heating the cell at the time of injecting the liquid crystal after cell assembly. A method of manufacturing the same is provided.

[0009]

Specifically, first, a glass substrate having a color filter is placed in a vacuum heating chamber before cell assembly by itself, the chamber is depressurized and heated, and the chamber is held for a predetermined time to obtain a color filter. Degas.

Then, the glass substrate facing the color filter substrate is assembled into a cell by a known method. Next, the cell is placed in the chamber of the liquid crystal injection device, the pressure in the chamber is reduced, the liquid crystal is brought into contact with the liquid crystal injection port of the cell, and then the chamber is returned to atmospheric pressure to fill the cell with the liquid crystal. To do.

At this time, since the degassing process of the color filter is performed on the substrate alone before the cell is assembled, it is not necessary to take a long vacuum holding time for degassing from the color filter when injecting the liquid crystal. The accompanying deformation of the cells can be suppressed, and a liquid crystal display device without generation of residual bubbles can be manufactured. In this case, the feature of the present invention is that the degassing treatment of the color filter substrate alone can be performed at a higher temperature than the reduced pressure heat treatment after the cell formation.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. That is, as shown in FIG. 2, the glass substrate 1
1, a color filter 12, a protective film 13, and a transparent electrode 1
4, the insulating film 15 is sequentially formed to form the color filter substrate 4.

The color filter substrate 4 is placed in the vacuum chamber 1 shown in FIG. 1 for degassing.
Then, after depressurizing the inside of the chamber 1 to 5 × 10 ⁻⁶ torr, the color filter substrate 4 is set to 1 by the far infrared heater 2.
After heating to 80 ° C. and holding under reduced pressure heating conditions for 6 hours, it is opened to normal temperature and normal temperature.

Thereafter, as shown in FIG. 3, an orientation control film 16 and a sealing material 19 are formed on the degassed color filter substrate 4. On the other hand, the opposite glass substrate 11a
After a transparent electrode (not shown), an insulating film 15a, and an alignment control film 16a are sequentially formed on the upper surface, spacers 18 and adhesive fine particles 17 are dispersed, and the color filter substrate 4 is superposed and adhered to form an empty cell (liquid crystal). Cells not implanted) are formed.

Then, the empty cell is placed in the chamber of the liquid crystal injecting apparatus, and the inside of the chamber is set to 5 × 10 ^-6 torr.
After depressurizing to 130 ° C., heating to 130 ° C. and holding for about 1 hour, antiferroelectric liquid crystal is supplied to the empty cell, and then opened to the atmosphere to inject liquid crystal.

FIG. 4 is a flow chart showing a method of manufacturing the liquid crystal display device according to the embodiment of the present invention. That is, on the color filter (CF) substrate side, after the transparent electrode / insulating film is formed in the first step S1, the second step S is performed.
In step 2, depressurization / heat treatment for degassing treatment is performed, and in the third step S3, an orientation control film is formed.

On the other hand, on the counter substrate side, after the transparent electrode / insulating film is formed in the fourth step S4, the orientation control film is formed in the fifth step S5. Next, in the sixth step, cell assembly is performed using the CF substrate and the counter substrate, and then the seventh step S
At 7, the liquid crystal is injected into the cell.

FIG. 5 graphically compares the results according to the embodiment of the present invention as described above and the results according to the conventional example in which the conditions are changed. That is, in the embodiment of the present invention, the color filter substrate before cell assembly was heated under reduced pressure (10 ⁻⁶ t).
Orr, 180 ° C. × 6 hours), the amount of change in cell gap is 0.09 even if the heating under reduced pressure in an empty cell (10 ⁻⁶ torr, 130 ° C. × 1 hour) is shortened.
It is extremely small (μm) and the amount of residual bubbles in the cell is 0 m.
It is m ² .

On the other hand, in the conventional example in which the pressure reduction heating is not performed on the color filter substrate before the cell assembly, if the pressure reduction heating and holding in the empty cell (10 ⁻⁶ torr, 130 ° C. × 1 hour) is short, the cell gap becomes small. Although it was as small as 0.08 μm, generation of residual air bubbles of 600 mm ² was recognized in the cell.

Further, in the conventional example 2 in which the color filter substrate before cell assembly is not heated under reduced pressure, if the vacuum cell heating and holding (10 ⁻⁶ torr, 130 ° C. × 11 hours) in the empty cell is lengthened, it remains in the cell. Although the amount of bubbles is 0 mm ² , the amount of change in cell gap is 0.25 μm, which is an extremely large value.

From the comparison between the present embodiment and the conventional example, it was confirmed that the effect of the present invention was good. In the above-described embodiment, the color filter substrate 4
Since the reduced pressure heat treatment of (1) is performed by itself before the cell assembly, it is not necessary to consider degassing from the color filter for the reduced pressure condition in the empty cell state in the liquid crystal injection step.

Therefore, since the holding time under reduced pressure heating in the empty cell state can be shortened, bubbles do not remain in the cell after the liquid crystal is injected, and the cell deformation (cell gap due to the stress associated with the reduced pressure heating is caused). Change) can also be reduced.

In this embodiment, the color filter substrate 4 is heated under reduced pressure after the insulating film 15 is formed.
The reduced pressure heat treatment may be performed before forming the insulating film 15 or before forming the transparent electrode 14.

[0024]

Therefore, as described in detail above, according to the present invention, the color filter substrate is subjected to the depressurization heat treatment in advance before the cell is assembled to degas the color filter. Provided is a method for manufacturing a liquid crystal display device capable of shortening a heating time under reduced pressure before injecting liquid crystal, suppressing cell deformation accompanying it, and preventing generation of residual bubbles in a cell after injecting liquid crystal. It becomes possible.

[Brief description of drawings]

FIG. 1 is a diagram showing a degassing process of a color filter substrate according to an embodiment of the present invention.

FIG. 2 is a diagram showing a color filter substrate used in one embodiment.

FIG. 3 is a diagram showing cell assembly of a color filter substrate and a counter substrate.

FIG. 4 is a flowchart showing a manufacturing process according to an embodiment of the present invention.

FIG. 5 is a diagram showing an effect of the present invention in comparison with a conventional one.

[Explanation of symbols]

1 ... Vacuum chamber, 2 ... Heater, 3 ... Substrate holder, 4 ...
Color filter substrate, 5 ... Valve, 6 ... Vacuum pump, 1
1 ... Glass, 12 ... Color filter, 13 ... Protective film, 1
4 ... Transparent electrode, 15 ... Insulating film, 11a ... Glass, 13a
... Protective film, 15a ... Insulating film, 16a, 16 ... Alignment control film, 17 ... Adhesive particles, 18 ... Spacer, 19 ... Seal.

Claims (2)

[Claims] 1. A method for manufacturing a liquid crystal display device in which a color filter substrate and a counter substrate are formed into cells, and the method further comprises a step of subjecting the color filter substrate to a single heat treatment under reduced pressure prior to cell assembly. Liquid crystal display device manufacturing method. 2. The liquid crystal display according to claim 1, wherein a heating temperature in the step of heat-treating the color filter substrate under reduced pressure is higher than a temperature for heating the cell at the time of injecting the liquid crystal after the cell is assembled. Device manufacturing method.