JPS6247027A - Liquid crystal display element - Google Patents

Abstract

PURPOSE:To prevent the elusion of an alkaline ion to the liquid crystal and to make an electrode pattern a poor appearance by providing an electrode substrate in which an insulating coating lying between a glass substrate and an electrode film is composed of a mixed film of SiO2-ZrO2-In2O3 to the title element. CONSTITUTION:The electrode film 13 is formed on the glass substrate 11 having an insulating coating 12 thereon followed by spattering it. And then, the electrode substrate 15 is prepared by patterning the prescribed electrode film and then by coating it with a polyimide film followed by rubbing it, thereby forming an orientation film 14. The two sheets of the prescribed electrode substrates 15 are sticked with each other through a sealing material 16 so as to have a cell gap of 10mum. The liquid crystal such as a nematic liquid crystal 17 is enclosed within the prescribed cell gap. The polarizing plates 18, 19 are sticked on an outer sides of each electrode substrates 15 respectively to form a twisted nematic type liquid crystal display element. The prescribed insulating coating is composed of 45wt% SiO2, 37wt% ZnO2 and 18wt% In2O3 on the basis of the oxide concentration. Thus, the electrode pattern becomes to the poor appearance in a nondriving of the title element and the title element having an improved visibility is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial Application Field" The present invention relates to a liquid crystal display element, and particularly to an insulating coating formed between a glass substrate and an electrode film of an electrode substrate.

"Prior Art" As shown in Fig. 1, a liquid crystal display element has a glass substrate
Insulating liquid It! uniformly formed on top! 112, an electrode film 13 formed on the insulating film 12 in a shape according to the display pattern, and an alignment film 14 that covers the electrode film 13 and the insulating film 12 so that the L plane becomes a flat surface. a pair of T's
An L-board 15 is provided. These electrode substrates 15.1
5 are bonded together with a sealing material 16 interposed therebetween to form a predetermined gap, and a liquid crystal 17 is sealed inside. In addition, in a twisted nematic type liquid crystal display element, a polarizing plate 18.19 is attached to the outside of the electrode substrate 15.15.

In conventional liquid crystal display elements, glass substrate! l and electrode n
The insulating film 12 interposed between the metal parts 13 is mainly formed of silicon dioxide (S i 02 ), titanium dioxide (Ti 02 ), etc. using a vacuum evaporation method or a chemical spray method.

"Problems to be Solved by the Invention" When forming the insulating coating 12, the vacuum evaporation method can provide an insulating coating with excellent characteristics, but there is a problem in terms of mass production.

Further, the chemical spray method has problems in that the properties of the resulting insulating film are poor and materials are likely to be wasted.

On the other hand, it is also possible to use a screen printing method, but there is a problem in terms of mass production.

Compared to the various methods described above, the immersion method is characterized in that it can process a large number of electrode substrates at the same time, does not waste materials, and is suitable for mass production.

However, when the insulating film 12 is formed using only SiO2 by the immersion method, the refractive index of the indium-tin (In-9
n) Since the refractive index is smaller than that of the electrode film 13 made of oxide, there is a problem that the electrode pattern stands out when the liquid crystal display element is not driven.

Furthermore, in order to increase the refractive index of the insulating coating 12, TiO2
It has also been attempted to layer two layers, but this has the problem of increasing the number of steps and increasing costs.

Further, if only a single layer of TiO7 is provided as the insulating film 12, alkaline ions such as sodium ions (Na'') are eluted from the glass substrate 11 to the liquid crystal 17.

There was a problem in which the display pattern blurred during reliability tests.

An object of the present invention is to prevent the elution of alkali ions into liquid crystals in order to solve the problems of the prior art described in 1-1.
Another object of the present invention is to provide a liquid crystal display element f- in which the refractive index of the insulating film is made close to that of the electrode film, thereby making the electrode pattern less visible, thereby improving reliability and display quality.

"Means for Solving the Problems" The liquid crystal display element of the present invention has an insulating film interposed between the glass substrate and the electrode film made of SiO2-ZrO, -1r+7
The present invention is characterized in that it includes an electrode substrate formed of a mixed film of No. 03.

"Function" In the liquid crystal display element according to the present invention, 5iQ2-Zr
The insulating coating consisting of a mixed film of 02111203 prevents the elution of alkali ions such as Na+ from the glass substrate to the liquid crystal (
At the same time, the refractive index of the insulating film approaches that of the electrode film, making the electrode pattern visible and improving the visibility of the liquid crystal display element.

"Embodiment of the Invention" In one embodiment of the liquid crystal display element of the present invention, SiO□
An insulating film made of a mixed film of -ZrO□-In203 is formed by a dipping method. That is, an organometallic compound of silicon (Si) soluble in organic solvents, zirconium (Zr)
An organometallic compound of indium (In) and an organometallic compound of indium (In) are dissolved in an organic solvent and reacted with each other, and a chelate product is added to stabilize the solution to uniformly distribute the generated reaction products. A glass substrate was immersed in this solution, and then baked to give a 5i
An insulating film made of a mixed film of OzZrO2rn20:+ is formed.

As the organometallic compound of Si, organic silane compounds such as tetramethoxysilane (SiCOCIIs>a), tetraethoxysilane, vinyltris(2-methoxyethoxy)silane, and ethyl silicate condensate can be preferably used.

Further, as the organometallic compound of Zr, tetraethoxyzirconium, tetraisopropoxyzirconium (Zr (OC3H7)4 ), tetraacetylacetonatozirconium, etc. can be preferably used.

Further, as the organometallic compound of In, triethoxyindium, triisopropoxyindium, trisacetylacetonateindium, tri-butoxyindium (In(OCntlJ*), triethylacetylacetylacetateindium (In(FAA)), etc. can be preferably used.

As the organic solvent for dissolving these organometallic compounds, methyl ethyl ketone (MEK), ethyl acetate, ethanol, methanol, etc. can be preferably used.

Furthermore, as the stabilizer for the solvent, acetylacetone, triethanolamine, etc. can be preferably used.

A solution created by mixing these is used as an immersion liquid, and after dipping a glass substrate in this and applying it,
When fired at a temperature of about 500℃, 5iQ2-Zr0
An insulating film made of a mixed film of 2In203 is formed.

By adjusting the viscosity of the t-1 immersion liquid containing Si, Zr, and In contained in the immersion liquid, the pulling speed of the glass substrate from the immersion liquid, etc., an insulating coating with a film thickness of about 5000 Å or less can be formed. Can be formed freely.

The content of each component in the insulating film thus formed was as follows: SiO2: 20-50% by weight, ZrO2: 25-4% by weight.
It is preferable that the amount of In2O3 be 10 to 20% by weight. If S+02 is less than 20% by weight, there will be a problem that the film forming property will deteriorate, and if 5iQ2 is less than 20% by weight,
If it exceeds % by weight, a problem arises in that the electrode pattern becomes easily visible. Further, if the ZrO2 content is less than 25% by weight, a problem arises in that the refractive index becomes low, and if the ZrO2 content exceeds 45% by weight, a problem arises in that cracks are likely to occur. Furthermore, if In2O3 is less than 10% by weight, the electrode pattern tends to bleed, resulting in poor reliability, while if 111203 exceeds 20% by weight, the insulation properties may be poor.

Example Nitriethyl acetylacetate A condensate of indium, tetrabutoxyzirconium, and ethyl silicate (S +y
lO'n-4(OC2Its)271+1. n #
5) and (7) & it total 28.4 times? An immersion liquid was prepared by adding 71.1 thousand j1:% of methyl ethyl ketone as an organic solvent and 0.5 tons+, t% of nitrocellulose as a viscosity agent.

Using this solution as an immersion liquid, a glass substrate was immersed in the same liquid, and then the glass substrate was pulled at a rate of EiOcm per minute of 30 to 6
Baked for 0 minutes. As a result, an insulating film with a thickness of about 1000 mm was formed on the glass substrate.

Note that this insulating film has an oxide concentration.

SiQ: 45% by weight, ZrO2: 37% by weight,
As shown in FIG. 1, a tai film was formed on the glass substrate 11h on which the insulating film 12 was formed by sputtering.

13 is formed and patterned. Furthermore, an alignment film 14 is formed by coating a polyimide film and rubbing it. In this way, the electrode substrate 15 can be obtained.

Next, the two electrode substrates 15 are pasted together through the sealing material 16 so that the cell cap becomes IOJLm, and for example, a nematic liquid crystal 17 is sealed inside, and each electrode substrate 15 is
By attaching polarizing plates 18 and 19 to the outside of the substrate, a twisted nematic type liquid crystal display element can be created.

The liquid crystal display element created in this way was 5iQ7-
Since it has an insulating coating made of a mixed film of ZrO7-1n203, the refractive index of the insulating coating can be adjusted to 1 depending on the Zr content.
．． It can be adjusted within the range of 6 to 1.75. Therefore, compared to the case where a single-layer SiO□ insulating film with a refractive index of 1.52 is used, the electrode pattern is less visible when not driven, and visibility as a liquid crystal display element is improved.

Furthermore, in this liquid crystal display element, distortion of the display pattern during driving, which is a criterion for determining whether or not alkali ions have eluted, is less likely to occur, so-called bleeding phenomenon.

For example, under an accelerated humidity test of 80° C. and 90%, the time required for the bleeding phenomenon to occur is approximately 30% longer than when a single SiO2 insulating film is used. Therefore, it is possible to provide a long-life liquid crystal display element with SJm.

"Effects of the Invention" - As explained above, according to the present invention, Zr and I
The effect of improving the elution prevention performance of alkali ions of Ha'''J can be obtained by the component n.

In addition, since the refractive index of the insulating film can be changed depending on the Zr content, by bringing the refractive index of the insulating film closer to that of the electric J41 film, the electrode pattern can be made less visible when not driven. is obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the general structure of a liquid crystal display element. In the figure, 11 is a glass substrate, 12 is an insulating coating, 13 is an electrode 11!2.14 is an alignment film, 15 is an electrode 8i substrate, and 17 is a liquid crystal.

Claims (2)

[Claims] (1) A liquid crystal display element comprising an electrode substrate in which the insulating film interposed between the glass substrate and the electrode film is formed of a mixed film of SiO_2-ZrO_2-In_2O_3. (2) In claim 1, the insulating coating includes SiO_2: 20 to 50% by weight and ZrO_2: 25 to 50% by weight.
A liquid crystal display element formed of a mixed film of 45% by weight and In_2O_3: 10 to 20% by weight.