WO2011089990A1 - Method for manufacturing display device - Google Patents

Abstract

Disclosed is a method for manufacturing a display device, wherein a conductive film is provided on a glass substrate without using a sputtering method. The method has: a chemical polishing step wherein an etching liquid is brought into contact with the surface of the glass substrate for the display device, and the arithmetic average roughness (Ra) of the glass surface is set at 0.7 nm-70 nm; and a film-forming step wherein a conductive polymer is applied to the glass surface that has been subjected to the chemical polishing step, and the conductive film having a resistivity of 400-1200 Ω/sq is formed. The total light transmittance of the glass substrate after being subjected to the film-forming step is set at 87 % or more, said glass substrate having a thickness of 0.5 mm.

Description

Manufacturing method of display device

The present invention relates to a method for manufacturing a display device in which a light-transmitting conductive film is provided on the surface of a glass substrate.

The liquid crystal display device is configured by enclosing a liquid crystal between a laminated glass substrate composed of a pair of glass substrates. When static electricity is charged on the glass substrate, the display operation of the liquid crystal is adversely affected. Therefore, a configuration is known in which charging is prevented by providing a conductive film on the surface of the glass substrate (for example, Patent Document 1).

Here, as the conductive film, indium tin oxide (ITO) is generally used, and the transparent electrode is formed by a sputtering method.

JP-A-8-241626

However, indium constituting the ITO is not only a rare metal, but there is a problem that not only a waste material is generated in the target material (ITO) as long as the sputtering method is employed.

Here, it is understood that the antistatic film on the surface of the exposed glass substrate exposed to the user is not required to have a resistivity as low as that of the transparent electrode, and it is sufficient to exhibit conductivity that can prevent charging. .

The present invention has been made in view of the above problems, and an object thereof is to provide a method for manufacturing a display device in which a conductive film is provided on a glass substrate without using a sputtering method.

In order to achieve the above object, a method for manufacturing a display device according to the present invention is such that an etching solution is brought into contact with the surface of a glass substrate for a display device so that the arithmetic average roughness Ra of the glass surface is 0.7 nm to 70 nm. A glass substrate after the film-forming step, and a film-forming step in which a conductive polymer is applied to the glass surface after the chemical-polishing step to form a conductive film of 400 to 1200 Ω / sq. The total light transmittance is 87% or more in a glass substrate having a thickness of 0.5 mm.

In the present invention, since the arithmetic average roughness Ra of the glass surface is set to 0.7 nm to 70 nm in the chemical polishing step, it is possible to achieve reliable adhesion with the conductive polymer. On the other hand, if Ra <0.7 nm and the glass surface is too flat, the adhesion of the conductive film by the conductive polymer is deteriorated, and in the adhesion test, there is a defect that it is easily peeled off by ethanol or the like. On the other hand, if Ra> 70 nm and the glass surface is too rough, clear display characteristics cannot be maintained as a display device.

In the film forming step of the present invention, a conductive polymer is applied to the glass surface to form a conductive film of 400 to 1200 Ω / sq. Here, the resistivity is not volume resistivity (Volume Resistivity: Ω · cm) but surface resistivity (Surface Resistivity: Ω / sq) per unit area (cm ² ) = volume resistivity / film thickness. In the case of transparent electrodes such as liquid crystal display devices, 5 to 4
A surface resistance value of about 0 Ω / sq is required, but 400 to 1200 Ω / sq is sufficient for antistatic applications. However, preferably, the glass substrate after the film forming step is set to a surface resistivity of 1000 Ω / sq or less.

In the present invention, it is preferable that the HAZE rate of the glass substrate after the film forming step is set to less than 1.5% when evaluated with a glass substrate having a thickness of 0.5 mm. Here, the HAZE rate means diffuse transmittance / total light transmittance × 100, and is a value specified based on JISＪK 7136.

Generally, the thicker the conductive film, the lower the surface resistivity and the higher the conductivity, but on the other hand, the HAZE ratio increases and the transparency decreases. In view of this point, the film thickness of the conductive polymer is preferably set to 100 nm to 250 nm.

The glass substrate of the present invention is preferably made of alkali-free glass, but more preferably should be made of aluminosilicate glass. As the conductive polymer, polyacetylene, polythiophenes and the like are preferably used, but more preferably, a polythiophene-based conductive polymer should be used.

The etching solution of the present invention is not particularly limited as long as the glass surface is moderately roughened, but preferably 0.5 to 3 wt% hydrofluoric acid, 0 to 10 wt% hydrochloric acid, 0 to 5 wt% Consists of sulfuric acid.

The display device of the present invention is preferably a liquid crystal display device, and the conductive polymer is formed on the exposed surface of the laminated glass substrate.

According to the present invention described above, a conductive film can be formed on a glass substrate without using a sputtering method, and an antistatic film can be formed at low cost.

Hereinafter, examples will be described, but the present invention is not particularly limited.

<Test glass>
A large number of glass plates of 100 mm × 100 mm × 0.6 mm aluminosilicate glass were prepared.

<Work procedure>
(1) Each glass plate was washed with water and chemically polished with an etching solution. In addition, various compositions were prepared as etching solutions, and the polishing time was also changed appropriately.
(2) After each glass plate was washed with water, it was immersed in IPA (isopropyl alcohol) for substitution treatment and dried with a dryer.
(3) Sepulzida (Shin-Etsu polymer), which is a polythiophene conductive polymer, was applied to the surface of the glass plate. Three groups applied to film thicknesses of about 120 nm, 160 nm, and 200 nm were generated using the bar coaters of No. 6, No. 8, and No. 10.
(4) Drying after applying the conductive polymer was performed in a drying furnace at 150 ° C. for 10 minutes.

<Result evaluation>
(1) Adhesion test About the dried glass plate, while performing the peeling test using a cellophane tape, the relationship with arithmetic mean roughness Ra after chemical polishing of each glass plate was verified.

As a result, it was confirmed that the adhesion between the glass and the conductive film was maintained when the arithmetic average roughness Ra was about 0.7 nm to 70 nm.

When the composition of the etching solution and the polishing time are changed, the arithmetic average roughness Ra of the glass plate after chemical polishing is changed. Generally, the longer the polishing time is, and the higher the hydrofluoric acid concentration is, the arithmetic average roughness is. Ra increases.

Therefore, considering the above tendency and workability, an etching solution comprising 0.5 to 3% by weight hydrofluoric acid, 0 to 10% by weight hydrochloric acid, 0 to 5% by weight sulfuric acid and the remaining water is used. In the chemical polishing step of several minutes (1-2 minutes), it was found that it is preferable to etch the glass surface by about 5 μm (single side: 2.5 μm).

(2) Optical characteristics Therefore, the total light transmittance, the surface resistivity, and the HAZE rate of the three groups of glass plates that have been subjected to the chemical polishing process set under the above conditions are as follows. It was. Here, the transmittance was measured based on JIS K 7361-1 using a spectral colorimeter SD-5000 (Nippon Denshoku Industries Co., Ltd.). The HAZE rate was measured based on JIS K 7136 using a turbidimeter NDH5000 (Nippon Denshoku Industries Co., Ltd.). The surface resistance was measured based on JIS K 7194 using Loresta MCP-T250 (Mitsubishi Chemical).

Claims (7)

A chemical polishing step in which an etching solution is brought into contact with the surface of a glass substrate for a display device to set the arithmetic average roughness Ra of the glass surface to 0.7 nm to 70 nm;
A film forming step of applying a conductive polymer on the glass surface after the chemical polishing step to form a conductive film of 400 to 1200 Ω / sq,
A method for manufacturing a display device, characterized in that a total light transmittance of a glass substrate after the film forming step is 87% or more in a glass substrate having a thickness of 0.5 mm. The manufacturing method according to claim 1, wherein the HAZE rate of the glass substrate after the film forming step is less than 1.5% for a glass substrate having a thickness of 0.5 mm. The method according to claim 1 or 2, wherein the film thickness of the conductive polymer is 100 nm to 250 nm. The method according to any one of claims 1 to 3, wherein the glass substrate is made of aluminosilicate glass. The production method according to any one of claims 1 to 4, wherein a polythiophene-based conductive polymer is used. 6. The etching solution according to claim 1, wherein the etching solution contains 0.5 to 3 wt% hydrofluoric acid, 0 to 10 wt% hydrochloric acid, and 0 to 5 wt% sulfuric acid. Production method. The manufacturing method according to claim 1, wherein the display device is a liquid crystal display device, and the conductive polymer is formed on an exposed surface of a laminated glass substrate.