JP3254338B2 - Spraying liquid for spacer for liquid crystal display element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spraying liquid containing spacers for controlling a cell gap by a wet spraying method in a process of manufacturing a liquid crystal display device.

[0002]

2. Description of the Related Art A liquid crystal display device generally has a high-speed response,
High contrast, wide viewing angle, high reliability, etc. are required.
Response speed, contrast, viewing angle, and the like are closely related to the cell gap. Therefore, the above requirements can be satisfied by setting the cell gap uniformly according to the optical characteristics of the liquid crystal material in the liquid crystal display element. Therefore, it is important to precisely control the distribution of the spacer for controlling the cell gap. There are two types of spacer spraying in the liquid crystal display element, dry spraying and wet spraying, and wet spraying has been mainly used conventionally.

In the manufacturing process by the wet spraying method, a spraying liquid in which spacers made of plastic beads are dispersed in a solvent is prepared, and the spraying liquid is atomized with compressed air, and is sprayed on a liquid crystal display substrate. Is bonded to another pair of substrates to obtain a liquid crystal display element.

Conventionally, a CFC-alcohol solvent having a specific gravity of 0.8 to 1.2 times that of the spacer material has been used (Japanese Patent Application Laid-Open No. 58-194015, Japanese Patent Application Laid-Open No. 1-156).
723). In recent years, the use of chlorofluorocarbon has become a problem due to the generation of an ozone hole and the like.
Pure water or alcohol is used as the solvent.

[0005]

In a spray liquid using pure water or alcohol as a solvent, the spacers are not sufficiently dispersed in the solvent, and a part of the spacers sprayed on the substrate aggregates. If the spacers are aggregated, the cell gap at that portion becomes thicker than set, and high contrast cannot be obtained or aggregation of the spacers can be visually observed, which causes point defects and causes defective products.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a liquid for dispersing a spacer for a liquid crystal display element having good dispersibility of the spacer without using Freon.

[0007]

According to the present invention, there is provided a liquid crystal display element spacer liquid in which a liquid crystal display element spacer is dispersed in a solvent comprising pure water and an alcohol, wherein the alcohol is: Containing isopropyl alcohol and methyl alcohol, or isopropyl alcohol and ethyl alcohol, wherein the mixing ratio of pure water and alcohol is in the range of 7: 3 to 6: 4,
Alcohol and methyl alcohol, or isopropyl alcohol
And a mixture ratio of ethyl alcohol to ethyl alcohol is 9: 1 .

[0008]

The present inventors have conducted various studies to achieve the above object, and as a result, as a solvent, purified water and isopropyl alcohol (IPA) and methyl alcohol, or alcohols including IPA and ethyl alcohol. It has been found that a mixture in a certain range has a good dispersibility of the spacer for a liquid crystal display element and a good distribution on a substrate when atomized by compressed air, thereby completing the present invention.

According to the present invention, in a mixed solution of pure water and an alcohol containing IPA and methyl alcohol, or IPA and ethyl alcohol, the mixing ratio of the pure water to the alcohol is 7: 3 to 6: 4. In this range, the plastic bead spacers are uniformly dispersed, and even when atomized with compressed air at the time of spraying, the spacers do not condense with each other and coagulation on the substrate is suppressed. Thus, when producing a liquid crystal display element, it is possible to improve the yield rate and uniformity of the screen of the liquid crystal display device. If the total amount of alcohols in the mixture is less than 3/10, the effect of adding alcohols is not sufficiently exhibited, and if it exceeds 4/10, there is a risk of explosion when compressed air is mixed. .

[0010] According to the present invention, IPA and methyl alcohol or the mixing ratio of the IPA and the ethyl alcohol, 9: 1 is preferred. Although the reason for this is not clear in detail, it is considered that the viscosity of the alcohol is suitable for dispersing the spacer at this mixing ratio .

[0011]

[0012]

The present invention will be described more specifically with reference to the following examples.

A solvent was prepared by mixing pure water, IPA and an added alcohol (methyl alcohol or ethyl alcohol) at the ratio shown in Table 1, and 100 g of this solvent and 3 g of spacer were prepared.
Was shaken by hand until the spacers were visually dispersed, stirred, and then irradiated with ultrasonic waves using an ultrasonic cleaning machine to completely disperse them, thereby obtaining a spray liquid.

[0014]

[Table 1]

The spray liquid in which the spacers are dispersed is put into a transparent rectangular column-shaped plastic cell 3 cm × 3 cm × 5 cm, and the length of the transparent upper layer is visually measured with the passage of time. It is shown in FIG.

[0016]

[Table 2]

The transparency of the spray liquid in which the spacers were dispersed was measured with MPS-2000 manufactured by Shimadzu Corporation. Table 3 shows the results.

[0018]

[Table 3]

If the degree of dispersion of the spacers in the spray liquid is low, the sinking speed of the spacers is increased, and the number of transparent upper layers increases rapidly. Also, the transparency increases quickly.

In Tables 1 to 3, Sample Nos. 1 to 3 are spray liquids composed of pure water and IPA, and Sample Nos. 4 to 9 are spray liquids composed of pure water, IPA and ethyl alcohol. Numerals 10 to 15 are spray liquids composed of pure water, IPA and methyl alcohol. The sample number with an asterisk indicates that the mixing ratio of pure water, IPA and ethyl alcohol or methyl alcohol is preferable.

From these tables, sample numbers 6, 8, 9, 1
The spray liquids of 1, 12, 14, and 15 have few upper layers which are transparent even after being left for 1 to 3 hours, have a low transmittance after 1.5 to 3 hours, and are well dispersed in the solvent. You can see that it is doing. In the dispersion with a large amount of added alcohol (sample numbers 4, 7, 10, 13 in which the ratio of IPA to ethyl alcohol or methyl alcohol is 1: 1),
Dispersion of the spacer in the solvent is poor. In the case where the added alcohol is ethyl alcohol, in a dispersion liquid containing a relatively large amount of the added alcohol (sample numbers 5 and 8 in which the ratio of IPA to ethyl alcohol is 3: 1), the transmittance of the sample number 5 containing a small amount of alcohol is slightly poor Is out. When other conditions are the same, the added alcohol is preferably methyl alcohol rather than ethyl alcohol.

Next, the spraying liquid in which the spacers were dispersed was sprayed on the substrate using compressed air, and a test for confirming the dispersibility was performed. In this test, the alcohol ratio was 3/1.
The dispersions of Sample Nos. 1, 6, and 11, which were 0 and had relatively good results in Tables 2 and 3, were used. In the test method, each spray liquid was sprayed on each of six substrates by creating compressed air,
The number of aggregates, 3 condensations and 4 or more condensations was measured at 5 points per substrate using a microscope. In addition, the number of agglomerations having a diameter of about 0.1 mm was visually measured. Table 4 shows the results.

[0023]

[Table 4]

From these results, it can be seen that the spray liquid obtained by adding methyl alcohol or ethyl alcohol to pure water and IPA has better dispersibility than the mixture of pure water and IPA.

[0025]

As described above, according to the present invention, pure water,
A mixture of isopropyl alcohol and methyl alcohol, or alcohols including isopropyl alcohol and ethyl alcohol at a certain ratio,
The liquid crystal display element spacers can be highly dispersed, and the optical characteristics of the liquid crystal display element can be improved.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroshi Fukuya 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka Sharp Corporation (72) Inventor Akihiro Hotta 22-22 Nagaikecho, Abeno-ku, Osaka City, Osaka Sharp Corporation (56) References JP-A-8-95065 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/339 B05D 7/00, 7/24

Claims (1)

(57) [Claims] 1. A solvent comprising pure water and alcohols,
A liquid for dispersing a liquid crystal display element spacer in which a liquid crystal display element spacer is dispersed, wherein the alcohols include isopropyl alcohol and methyl alcohol, or isopropyl alcohol and ethyl alcohol, and a mixing ratio of pure water and alcohols. Is in the range of 7: 3 to 6: 4 , and isopropyl alcohol and methyl alcohol, or
Mixing ratio of isopropyl alcohol and ethyl alcohol
Is 9: 1 , the spray liquid for a spacer for a liquid crystal display element.