JPH0728044A - Production of liquid crystal display element - Google Patents

Abstract

PURPOSE:To optimize the refractive index of a film to be formed on a substrate glass and to improve the process fluidization stability by incorporating at least three components of SiO2, TiO2 and ZrO2 as the insulating layer forming components. CONSTITUTION:The refractive index of an insulating layer consisting essentially of SiO2 and having about 1.45 refractive index is changed to 1.6 to 1.7 by adding high-refractive-index components of TiO2 and ZrO2. For example, alumina sol is used as the metal oxide fine particle and ethyl silicate as the metal alkoxide. The compds. are diluted to the solid concn. of 5 to 10wt.% with a solvent such as methanol, ethanol, methyl cellosolve and ethyl cellosolve. This soln. is mixed with a soln. contg. 5-10wt.% of TiO2 and ZrO2 prepared by diluting the tetraethoxytitanium and tetraethoxyzirconium for controlling the refractive index with the solvents. This liq. sol is applied on an electrode formed on a substrate glass and heated to form the insulating film.

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 element 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 used 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. In addition, SiO ₂ and TiO ₂
It has been confirmed that a certain degree of improvement can be achieved by forming a mixed film of and increasing the refractive index, but due to the addition of TiO ₂ , the alkali resistance is difficult, and sufficient strength cannot be obtained due to film reduction in the alkali cleaning step. There is also a problem.

An object of the present invention is to solve the above-mentioned problems by providing a method of manufacturing a liquid crystal display device having an optimized refractive index of a film formed on a substrate glass and excellent process flow stability. Especially.

[0005]

SUMMARY OF THE INVENTION The above object is to improve the refractive index of an insulating layer containing SiO ₂ as a main component and having a refractive index of about 1.45 by adding high refractive index components of TiO ₂ and ZrO ₂ . It can be achieved by setting it to 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 interface of the film. , ZrO with good alkali resistance
The addition of ₂ makes it possible to achieve a smooth flow in the alkali cleaning step.

[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, tetraethoxytitanium and tetraethoxyzirconium are diluted with a solvent similar to the above to make TiO ₂ and ZrO ₂ , and 5 to 10 w.
After adjusting to t%, it was 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. No particular problems occurred in the subsequent substrate alkali cleaning step. Further, an alignment film was laminated and rotary rubbing was performed, but the alignment film was not peeled off. When a liquid crystal display device having a liquid crystal sandwiched therein was used and the display characteristics were evaluated, the ITO transparent electrode did not appear and showed extremely stable display characteristics 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 content concentration of 5 to 10% by weight to obtain a liquid sol.

On the other hand, in order to adjust the refractive index, tetraethoxytitanium and tetraethoxyzirconium are diluted with a solvent similar to the above to make TiO ₂ and ZrO ₂ , and 5 to 10 w.
After adjusting to t%, it was mixed with the above solution.

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. No particular problems occurred in the subsequent substrate alkali cleaning step. Further, an alignment film was laminated and rotary rubbing was performed, but the alignment film was not peeled off. When a liquid crystal display device having a liquid crystal sandwiched therein was used and the display characteristics were evaluated, the ITO transparent electrode did not appear and showed extremely stable display characteristics 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, tetraethoxytitanium and tetraethoxyzirconium are diluted with a solvent similar to the above to make TiO ₂ and ZrO ₂ , and 5 to 10 w.
After adjusting to t%, it was mixed with the above solution.

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 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. No particular problems occurred in the subsequent substrate alkali cleaning step. Further, an alignment film was laminated and rotary rubbing was performed, but the alignment film was not peeled off. When a liquid crystal display device having a liquid crystal sandwiched therein was used and the display characteristics were evaluated, the ITO transparent electrode did not appear and showed extremely stable display characteristics for a long time.

Comparative Example Alumina sol (Alumina sol 5) having an average particle diameter of 100 to 200Å as fine particles of metal oxide.
20, 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, tetraethoxy titanium is diluted with a solvent similar to the above to make TiO ₂ and the content is 5-1.
After adjusting to 0 wt%, it was mixed with the above solution.

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. However, in the subsequent alkali cleaning of the substrate, the film components were eluted and the film hardness became insufficient, making it unusable.

[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 (1)

[Claims] 1. A liquid crystal display device having a structure in which a liquid crystal layer is sandwiched between electrodes and having an insulating layer on at least one electrode, wherein at least SiO is used as an insulating layer forming component.
_A method of manufacturing a liquid crystal display device, which comprises three components of ₂ , ₂ , TiO ₂ , and ZrO ₂ .