JPH02216126A - Spacer for liquid crystal display element - Google Patents

Abstract

PURPOSE:To obtain the spacer which prevents the damage of transparent electrodes and can uniformly control the gap between substrates with high accuracy by using glass fibers which are subjected to a dissolution treatment by an etching liquid to smooth both ends and have the standard deviation value of the diameter distribution at <=1.5% with respect to the average diameter. CONSTITUTION:The glass fibers to be dispersedly disposed between the substrates of a liquid crystal display element in order to control the gap between the substrates usually have sharp rugged shapes at both ends thereof which damage the transparent electrodes and lead to a disconnection in the case of using the glass fibers which are cut by means, such as grinding. The glass fibers to be used as the spacers are immersed into the glass etching liquid (for example, a hydrofluoric acid system or strong alkali system) in order to remove the ruggedness at the end faces of the glass fibers to smooth the end faces and to use the fibers as the spacers. The etching is executed by controlling the concn. and temp. of the soln. and the time in such a manner that the standard deviation value of the diameter distribution of the glass fibers attains <=1.5% with respect to the average diameter.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a spacer used for uniformizing the spacing between substrates in a liquid crystal display element.

[Problems to be solved by conventional techniques and inventions] Conventionally,
As a method of controlling the gap between the substrates that sandwich the liquid crystal layer of a liquid crystal display element, a method of using spacers made of resin beads or cylindrical glass fibers has been used.

Recently, a method using resin bead spacers has been widely used, but in this case, the standard deviation of the resin bead particle size distribution is about 0.4 μl, and the particle size accuracy is poor (and the gap control between the substrates is difficult over a large area). In particular, gap control for liquid crystal display devices that use polymer films as substrates is difficult due to their flexibility, and resin beads with a small standard deviation of particle size distribution are required, but classification of resin beads is difficult. There is a limit to how accurately it can be made, and the cost is high.

On the other hand, when glass fiber is used, the standard deviation of its diameter distribution is approximately 0.07 μm, which can be controlled with high precision. However, since the glass fiber is cut and used, the end face is extremely uneven when it is cut, and these unevenness can damage the transparent electrode and cause wire breakage. As described above, glass fiber is an effective material for gap control as long as the transparent electrode is not damaged.

The present invention has been made in view of the problems of the prior art as described above, and provides a spacer for liquid crystal display elements that can prevent damage to transparent electrodes and uniformly control the gap between substrates with high precision. The purpose is to provide.

[Means to solve the problem]

To achieve the above object, according to the present invention, the glass fiber is made of a glass fiber whose both end faces are smoothed by melting with an etching solution, and the standard deviation value of the diameter distribution of the glass fiber is 1°5z or less of the average diameter. Provided is a spacer for a liquid crystal display element characterized by an accuracy of .

The glass fibers distributed in order to control the gap between the substrates of the liquid crystal display M'f- are usually cut by pulverization or other means, so their end faces have sharp irregularities and may damage the transparent electrode film. , which caused wire breakage, making it unsuitable for use. The present invention prevents damage to the transparent electrode film by removing such unevenness and smoothing the end face of the glass fiber, and by determining the diameter accuracy as described above, it can be used as a high-precision spacer. This makes it possible to

In order to smooth the end face of the glass fiber, it may be treated with a liquid that is soluble in glass. Examples of such solutions include conventionally known glass etching solutions, such as hydrofluoric acid-based (a mixed solution of hydrofluoric acid and ammonium fluoride) and strong alkaline-based solutions (saturated ethanolic solution of potassium hydroxide, saturated aqueous solution of sodium hydroxide). etc.) can be used. Glass fibers to be used as spacers are immersed in this etching solution. Through this immersion process,
The one end surface of the glass fiber is smoothed by melting the unevenness. FIG. 1 shows an enlarged view of the appearance of the glass fiber after dipping treatment. Furthermore, FIG. 2 shows an enlarged view of the appearance of the glass fiber before dipping treatment.

In the above-mentioned dipping treatment, the entire surface of the glass fiber is also etched, but if the etching is excessive, the variation in the diameter distribution of the glass fiber becomes large, which is undesirable as it causes the color of the liquid crystal display element to change. Therefore, both end faces of the glass fiber are smoothed,
In addition, the concentration, temperature, and time of the solution are controlled so that the standard deviation value of the diameter distribution of the glass fibers is 1.5% or less of the average diameter, so that appropriate etching is performed. During the immersion treatment, it is preferable to use stirring means in order to equalize the solution concentration, for example,
It is preferable to use stirring means such as ultrasonic dispersion.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.6 Example IH Glass fiber (trade name: Microd PF-62) manufactured by Hondensaku Glass Co., Ltd.
wt%, ammonium fluoride 18.2 wt% and acetic acid 7
It was immersed in a reaction solution consisting of 6.8 wt% and heated at 50°C for 10
Etched for a minute. The end face of the glass fiber treated in this manner was smoothed as shown in FIG. 1, and the standard deviation value of the diameter distribution was 1.31 with respect to the average diameter.

This glass fiber was adjusted to a concentration of 6ffig/cc in Freon IE (Ei Fluorochemical #!5) solvent, and was used as a spacer material.

A uniaxially stretched polyethylene terephthalate film with a thickness of 100 mm on which ITO electrodes were formed was used as a substrate, and the ITO electrodes were patterned using a photolithography method.
After forming upper and lower electrode plates and applying an alignment film made of polyamide, a rubbing treatment was performed.

On one of the substrates, the spacers with the vR adjusted above were dispersed at a density of 50 pieces/! using a spray-like method. A sealant made of flexible epoxy adhesive was printed on the other substrate, and after the upper and lower substrates were bonded together, they were sealed by heat curing.The adhesive was cured.Next, the liquid crystal (Product name: RCR4
011LA (manufactured by Chisso Corporation)) was sealed between the side substrates to form a liquid crystal cell.

In the liquid crystal cell produced as described above, no damage was observed to the transparent electrode, and no color unevenness occurred.

Example 2 A spacer was prepared in the same manner except that a reaction solution having the composition shown in Table 1 below was used, and a liquid crystal cell was similarly prepared using the spacer. As in Example 1, a transparent cell was obtained. No damage was observed to the electrodes, and no color unevenness occurred.

Comparative Examples 1 to 8 Spacers were prepared in the same manner as in Example 1, except that the reaction solutions shown in Table 1 were used and the reaction times were set as shown in Table 1. A liquid crystal cell was similarly produced using the same method. The glass fibers were all etched excessively, and although the end faces were smoothed and the transparent electrode was not damaged, the standard deviation value of the diameter distribution was 5 or more compared to the average diameter, indicating that the uniformity of the cell gap was poor. The condition deteriorated, and some color unevenness was observed.

〔Effect of the invention〕

As explained in detail above, according to the present invention, glass fibers are made of glass fibers whose both end faces are smoothed by dissolving with an etching solution and whose diameter distribution standard or deviation value is 1.5% or less with respect to the average diameter. By configuring the spacer for a liquid crystal display element, the transparent electrode is not damaged and disconnection is prevented, and furthermore, it is possible to provide a liquid crystal display element with high display quality in which the occurrence of color unevenness is prevented by improving the cell gap precision.

[Brief explanation of the drawing]

FIG. 1 is an enlarged view showing the appearance of the glass fiber after dipping treatment, and FIG. 2 is an enlarged view showing the appearance of the glass fiber before dipping treatment. Patent applicant Rico Co., Ltd.

Claims (1)

[Claims] (1) The glass fiber is made of a glass fiber whose both end faces are smoothed by melting treatment with an etching solution, and the glass fiber is characterized in that the standard deviation value of the diameter distribution is accurate to 1.5% or less of the average diameter. Spacer for liquid crystal display elements.