JPH05323331A - Liquid crystal display manufacturing method - Google Patents

Abstract

(57) [Summary] [Purpose] Spacers are evenly dispersed on the alignment film on the transparent substrate. [Structure] Spacer 1 initially charged with negative charge
4 is immersed in a cationic surfactant solution to charge the spacer 14 with a positive charge, and
The negative charges are scattered on the oriented film 13. Adsorption force acts between the spacer 14 having a positive charge and the alignment film 13 having a negative charge, and the spacer 14
And the adhesion of the alignment film 13 is improved. In addition, the spacer 14
The same charge causes repulsive force with the same charge, and this repulsive force causes spacer 1
4 is prevented. From these, the spacers 14 can be uniformly dispersed on the alignment film 13.

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 more particularly to a method for dispersing spacers on an alignment film on a transparent substrate.

[0002]

2. Description of the Related Art Liquid crystal display devices are used as displays for electronic devices such as word processors. The general structure of this liquid crystal display device is shown in FIG. In this liquid crystal display device, a pair of transparent substrates 3 and 4 having a transparent electrode 1 and an alignment film 2 on opposite surfaces are provided to face each other with a spacer 5 sandwiched between the alignment films 2, and the alignment films 2 are arranged to face each other. The liquid crystal 6 is injected into the gap and the periphery between the transparent substrates 3 and 4 is sealed with a sealing material 7.

In such a liquid crystal display device, the spacers 5 are made of particles of about 10 μm, and are used to keep the distance between the alignment films 2 (about 10 μm) constant and to keep the display characteristics uniform. This spacer 5 is used as an alignment film 2
As a method of interposing a large number of them between each other, a method of dispersing spacers 5 on the upper surface of the alignment film 2 provided on one transparent substrate (for example, the transparent substrate 4) is adopted.

As a method of spraying the spacers 5, conventionally, the spacers 5 are dispersed in a dispersion solvent liquid, and the solvent liquid is sprayed by spraying or the like, or the solvent liquid is vaporized during spraying. Only the method of spraying is taken.

[0005]

By the way, the spacer 5
When the resin is formed of a resin such as divinylbenzene or benzoquanamine, the spacer 5 is generally negatively charged by static electricity. On the other hand, the alignment film 2 is the transparent substrate 4
It is formed by applying an alignment material on the top and baking it, and then subjected to a predetermined rubbing treatment, but a negative charge is charged by static electricity due to the rubbing treatment. Moreover, as shown in FIG. 3, the alignment film 2 has a small amount of charge because the charge easily escapes through the transparent electrode 1 in the portion overlapping with the transparent electrode 1, and the charge does not easily escape in the portion between the transparent electrodes 1. The amount is larger than that of the portion overlapping the transparent electrode 1. Therefore, when the spacers 5 are scattered on the alignment film 2, a repulsive force acts between the alignment film 2 and the spacer 5 which are negatively charged, but the transparent electrode 1 having a relatively large charge amount in the alignment film 2. Since the repulsive force with the spacer 5 is smaller in the portion overlapping with the transparent electrode 1 having a relatively smaller charge amount than between them, the spacer 5 is likely to aggregate in the portion of the alignment film 2 overlapping with the transparent electrode 1, The spacers 5 could not be evenly distributed on the alignment film 2. This tendency is particularly great when the transparent substrate 4 is a resin substrate and the alignment film 2 is charged more during the rubbing treatment than the glass substrate. Needless to say, if the spacers 5 cannot be evenly distributed on the alignment film 2, the uniformity of the spacing between the pair of alignment films 2 is reduced, and the display quality of the liquid crystal display device is also reduced.

An object of the present invention is to provide a method of manufacturing a liquid crystal display device in which spacers can be uniformly dispersed on an alignment film.

[0007]

According to the present invention, in a method of manufacturing a liquid crystal display device in which spacers are scattered on an alignment film on a transparent substrate, the spacers are immersed in a cationic surfactant solution. The method comprises the steps of: charging the spacers with a positive charge by means of; and spraying the spacers charged with a positive charge on the alignment film.

[0008]

According to the present invention, since the spacer is charged with a positive charge by the immersion treatment in the cationic surfactant solution, the adhesion with the alignment film charged with a negative charge is improved, and the spacer is The repulsive force due to the same charge acts on each other to prevent aggregation, and spacers can be evenly dispersed on these from the alignment film.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG. 2 is a schematic view showing changes in the charged state of spacers in the embodiment. An embodiment of the present invention will be described below with reference to these drawings. First, as shown in FIG. 1, a transparent electrode 12 made of ITO or the like is patterned on a transparent substrate 11 made of glass or resin. Next, an alignment material is applied to the surface of a predetermined region including the transparent electrode 12 of the transparent substrate 11,
After that, the alignment film 13 is formed by baking, and then a predetermined rubbing process is performed.

On the other hand, a spacer 14 made of a resin such as divinylbenzene or benzoquaminan and having a dimension of about 10 μm is prepared. The spacer 14 is negatively charged by static electricity as shown in FIG. By immersing the spacer 14 in a cationic surfactant solution such as triethanolamine,
As shown in (b), a positive charge is adsorbed on the spacer 14. Since the amount of the positive charges adsorbed at this time is larger than the amount of the negative charges that have been charged in advance, the charged state of the spacer 14 is in the positive charged state as shown in FIG. 2C. .. The spacers 14 charged with the positive charges are washed with water to remove impurities, and then water is removed by filtration or drying. After that,
The spacer 14 is mixed and dispersed in a dispersion solvent such as isopropyl alcohol or chlorofluorocarbon. Then, by spraying this dispersion solvent on the alignment film 13 by spraying or the like, the spacers 14 are spread on the alignment film 13 as shown in FIG.

As described above, the scattered spacers 14 are positively charged, while the alignment film 13 is negatively charged by the rubbing treatment, so that an attractive force acts between them. Alignment film 13 and spacer 1
The adhesiveness of 4 is improved. Further, the spacers 14 have the same charge and a repulsive force works, and the repulsive force prevents the spacers 14 from aggregating. Here, looking at the charged state of the alignment film 13 in detail, the alignment film 13 is affected by the transparent electrode 12 as described above, and the amount of negative charge is small in the transparent electrode 12 portion. The amount of negative charges is large in the area between the two. Therefore, the spacer 1
When 4 is charged with a positive charge, the spacer 1 is provided between the transparent electrodes 12 having a large negative charge.
4 may be aggregated, but here spacer 1
Since the charge amount of the positive charges of 4 is not so large that the spacers 14 repel each other, the influence of the charge amount of the alignment film 13 is hardly exerted, and the spacers 14 are aggregated between the transparent electrodes 12. There is no. Then, the spacers 14 prevent the aggregation due to the repulsive force of the same charges, and the alignment film 1
According to this method, the spacers 14 can be uniformly dispersed on the alignment film 13 by improving the adhesion between the spacers 3 and the spacers 14.

After that, as is clear from the general structure diagram of FIG. 3, a sealing material is formed by printing on the upper surface of the periphery of the transparent substrate 11 except for the liquid crystal injection port, and then the transparent substrate 11 side is formed. Similarly, the transparent substrate on the opposite side on which the transparent electrode and the alignment film are formed is placed on the transparent substrate 11 so as to face each other, the periphery of both substrates is attached with a sealing material, and liquid crystal is injected into the gap between the alignment films. The liquid crystal display device is completed by sealing the inlet.

[0013]

As described above, according to the present invention, the spacers are charged to a positive charge by the immersion treatment in the cationic surfactant solution and dispersed on the alignment film. The adhesion of the film can be improved, and the repulsive force due to the same charge of the spacers can prevent the aggregation, so that the spacers can be uniformly dispersed on the alignment film. Therefore, the spacers can keep the distance between the alignment films uniform over the entire area, and the display quality of the liquid crystal display device can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a method for manufacturing a liquid crystal display device of the present invention.

FIG. 2 is a schematic diagram showing changes in the charged state of spacers in one embodiment of the present invention.

FIG. 3 is a sectional view showing a general structure of a liquid crystal display device.

[Explanation of symbols]

 11 transparent substrate 12 transparent electrode 13 alignment film 14 spacer

Claims (1)

[Claims] 1. A method of manufacturing a liquid crystal display device, wherein spacers are dispersed on an alignment film on a transparent substrate, and the spacers are immersed in a cationic surfactant solution to charge the spacers with a positive charge. And a step of spraying the positively charged spacers on the alignment film.