JPH06289379A - Production of liquid crystal display element - Google Patents

Abstract

PURPOSE:To improve the adhesion property to substrates, the reliability of film hardness and the adhesion property to oriented films by consisting the element of a structure in which a liquid crystal layer is clamped between electrodes and which has an insulating layer having the refractive index of a specific range on the electrodes on one side. CONSTITUTION:An alumina sol having 100 to 200Angstrom average particle sizes is used as metal oxide particulates and ethyl silicate is used as a metal alkoxide. The ethyl silicate diluted by a solvent, such as methanol, to 5 to 10wt.% solid- component concn. is used. On the other hand, an aq. soln. of cerium chloride for adjusting the refractive index is diluted by its solvent to 5 to 10wt.% as CeO2, which is then mixed with the solvent. This liquid sol is applied on a substrate by controlling the thickness to 800 to 900Angstrom and is heated to form the insulating layer. This insulating layer has 1.6 to 1.7 refractive index. The difference in the refractive index between the insulating layer and the transparent electrodes of ITO and oriented films is eliminated. The reflection at the boundary of the films and the appearance of the transparent electrodes of the ITO on a screen by interference are prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a liquid crystal display device which has a uniform display and is excellent in manufacturing stability.

[0002]

2. Description of the Related Art In a liquid crystal display device having a structure in which a liquid crystal layer is sandwiched between electrodes, it is essential to form an insulating layer in order to prevent a short circuit between electrodes due to a conductive foreign substance. As an insulating layer on an electrode in a conventional liquid crystal display device, a sputtered film such as SiO ₂ or a sol obtained by hydrolyzing an alkoxysilane (for example, NTL6008, manufactured by Nissan Kagaku Co., Ltd.) is coated and baked, and SiO ₂ is contained as a main component. It was using a membrane.

[0003]

However, in the above-mentioned conventional insulating film, SiO ₂ is the main component and the refractive index is around 1.45. This is much smaller than 1.6 to 1.7 of the transparent electrode (ITO) and the alignment film (polyimide etc.), so that light reflection or interference occurs at the film interface, so that the ITO transparent electrode can be seen on the screen and displayed. There was a problem that the appearance deteriorated.

An object of the present invention is to solve the above-mentioned problems by providing a method of manufacturing a liquid crystal display device in which the refractive index of a film formed on a substrate glass is optimized.

[0005]

SUMMARY OF THE INVENTION The above-mentioned object is to make the refractive index of an insulating layer mainly composed of SiO ₂ and Al ₂ O ₃ and having a refractive index of around 1.45 CeO ₂ or TiO ₂ or T.
This can be achieved by adding a high refractive index component such as hO ₂ to 1.6 to 1.7.

[0006]

According to the method of the present invention, there is no difference in refractive index between the insulating layer and the ITO transparent electrode and the alignment film, and it is possible to prevent the ITO transparent electrode from being visible on the screen due to reflection or interference at the film interface. It is a thing.

[0007]

【Example】

(Example 1) An average particle diameter of 100 as metal oxide fine particles.
~ 200Å alumina sol (Alumina sol 520, manufactured by Nissan Kagaku Co., Ltd.), ethyl silicate as metal alkoxide, and solvent such as methanol, ethanol, methyl cellosolve, ethyl cellosolve, etc. with a solid concentration of 5 to 1
The one diluted to 0 wt% was used.

On the other hand, in order to adjust the refractive index, 4 of cerium chloride is used.
The 0% aqueous solution was diluted with the same solvent as described above to make CeO ₂ to 5 to 10 wt%, and then mixed with the above solution.

As the substrate, an electrode was used in which a conductive film such as ITO was formed by sputtering or vapor deposition using Pyrex glass or soda lime glass whose surface was optically polished, and a pattern was formed by photoetching to form an electrode.

The liquid sol was coated on this substrate by roll coating while controlling the film thickness to 800 to 900Å, and heated at 400 ° C. for 1 hour to form a stable insulating layer. The insulating layer thus formed was homogeneous over a large area, sufficient reliability was obtained even in a film hardness test by pressing with a metal needle, and adhesion with the substrate was secured. When the refractive index of the film was measured by an ellipsometer, it was 1.7.
It was about. Further, an alignment film was laminated and rotary rubbing was performed, but the alignment film was not peeled off. A liquid crystal display device having a liquid crystal sandwiched therebetween was used to evaluate the display characteristics.
The TO transparent electrode showed extremely stable display characteristics without being visible and for a long time.

Example 2 As the metal oxide fine particles, silica sol having an average particle diameter of 100 to 200Å (Snowtex O, manufactured by Nissan Chemical Co., Ltd.) was used. Further, ethyl silicate was used as the metal alkoxide, mixed with 0.02N hydrochloric acid and stirred vigorously to prepare a hydrolysis solution. Next, the silica sol and the hydrolyzed solution were mixed and diluted with a solvent such as methanol, ethanol, methyl cellosolve or ethyl cellosolve to a solid concentration of 5 to 10% by weight to obtain a liquid sol.

On the other hand, in order to adjust the refractive index, thorium nitrate 4
The 0% aqueous solution was diluted with the same solvent as above to make ThO ₂ to 5 to 10 wt%, and then mixed with the liquid sol.

In the same manner as in Example 1, using a Pyrex glass or soda lime glass whose surface is optically polished as a substrate, a conductive film such as ITO is formed by sputtering or vapor deposition, and a pattern is formed by photoetching to form an electrode. Was used.

The liquid sol was applied onto this substrate by roll coating while controlling the film thickness to 800 to 900Å, and heated at 400 ° C. for 1 hour to form a stable insulating layer. The insulating layer thus formed was homogeneous over a large area, sufficient reliability was obtained even in a film hardness test by pressing with a metal needle, and adhesion with the substrate was secured. When the refractive index of the film was measured by an ellipsometer, it was 1.7.
It was about. Further, an alignment film was laminated and rotary rubbing was performed, but the alignment film was not peeled off. A liquid crystal display device having a liquid crystal sandwiched therebetween was used to evaluate the display characteristics.
The TO transparent electrode showed extremely stable display characteristics without being visible and for a long time.

Example 3 As the metal oxide fine particles, an alumina sol (alumina sol 520, manufactured by Nissan Chemical Co., Ltd.) having an average particle size of 100 to 200 Å was used. Further, ethyl silicate was used as the metal alkoxide, mixed with 0.02N hydrochloric acid and stirred vigorously to prepare a hydrolysis solution. Next, the above-mentioned alumina sol and the hydrolyzed solution were mixed and diluted with a solvent such as methanol, ethanol, methyl cellosolve or ethyl cellosolve to a solid content concentration of 5 to 10% by weight to obtain a liquid sol.

On the other hand, in order to adjust the refractive index, ethoxy titanium is diluted with a solvent similar to the above to make TiO ₂ , and 5 to 10 wt.
%, And then mixed with the above liquid sol.

In the same manner as in the above-mentioned embodiment, a Pyrex glass or soda lime glass whose surface is optically polished is used as a substrate, a conductive film such as ITO is formed by sputtering or vapor deposition, and a pattern is formed by photoetching to form an electrode. Was used.

The liquid sol was applied onto this substrate by roll coating while controlling the film thickness to 800 to 900Å and heated at 400 ° C. for 1 hour to form a stable insulating layer. The insulating layer thus formed was homogeneous over a large area, sufficient reliability was obtained even in a film hardness test by pressing with a metal needle, and adhesion with the substrate was secured. When the refractive index of the film was measured by an ellipsometer, it was 1.7.
It was about. Further, an alignment film was laminated and rotary rubbing was performed, but the alignment film was not peeled off. A liquid crystal display device having a liquid crystal sandwiched therebetween was used to evaluate the display characteristics.
The TO transparent electrode showed extremely stable display characteristics without being visible and for a long time.

Example 4 As the metal oxide fine particles, an alumina sol having an average particle size of 100 to 200 Å (alumina sol 520, manufactured by Nissan Chemical Co., Ltd.) was used. Further, ethyl silicate was used as the metal alkoxide, mixed with 0.02N hydrochloric acid and stirred vigorously to prepare a hydrolysis solution. Next, the above-mentioned alumina sol and the hydrolyzed solution were mixed and diluted with a solvent such as methanol, ethanol, methyl cellosolve or ethyl cellosolve to a solid content concentration of 5 to 10% by weight to obtain a liquid sol.

On the other hand, in order to adjust the refractive index, 4 of cerium chloride is used.
A 0% aqueous solution was diluted with the same solvent as described above to make CeO ₂ to 5 to 10 wt%, and then mixed with the above liquid sol.

Similar to the above-described embodiment, a substrate is made of Pyrex glass or soda lime glass whose surface is optically polished, a conductive film such as ITO is formed by sputtering or vapor deposition, and a pattern is formed by photoetching to form an electrode. Was used.

The liquid sol was applied onto this substrate by roll coating while controlling the film thickness to 800 to 900Å and heated at 400 ° C. for 1 hour to form a stable insulating layer. The insulating layer thus formed was homogeneous over a large area, sufficient reliability was obtained even in a film hardness test by pressing with a metal needle, and adhesion with the substrate was secured. When the refractive index of the film was measured by an ellipsometer, it was 1.7.
It was about. Further, an alignment film was laminated and rotary rubbing was performed, but the alignment film was not peeled off. A liquid crystal display device having a liquid crystal sandwiched therebetween was used to evaluate the display characteristics.
The TO transparent electrode showed extremely stable display characteristics without being visible and for a long time.

[0023]

As described above, according to the present invention, a liquid crystal which can be formed at a relatively low temperature and which is excellent in adhesion to a substrate, reliability of film hardness, and adhesion to an alignment film and has a good appearance. Providing a display element makes it possible to manufacture a display device which is inexpensive and has long-term reliability. The liquid crystal display device of the present invention is easy to form an insulating layer, is less likely to cause alignment failure, and has a good display appearance. Therefore, it is advantageous for producing a particularly large area.

Claims (3)

[Claims] 1. A liquid crystal display device having a structure in which a liquid crystal layer is sandwiched between electrodes, and the insulating layer has a refractive index of 1.6 to 1.7 in a liquid crystal display device having an insulating layer on at least one of the electrodes. And a method for manufacturing a liquid crystal display device. 2. The method for producing a liquid crystal display device according to claim 1, wherein the insulating layer is formed by applying a liquid sol containing metal oxide fine particles and a metal alkoxide as main raw materials and heating the liquid sol. 3. The insulating layer according to claim 1 or 2, wherein the insulating layer is Si.
A method for producing a liquid crystal display device, which is formed of O ₂ , Al ₂ O _3, and any one of CeO ₂ , TiO ₂ , and ThO ₂ .