JPS62176946A - Inorganic plate having antistatic property and low reflectivity - Google Patents

Abstract

PURPOSE:To obtain the titled inorg. plate which can be most appropriately used as the cathode-ray tube for a display by providing many specified protrusions and a transparent inorg. coated film on the surface of an inorg substrate. CONSTITUTION:The inorg. plate consists of the inorg. substrate and the transparent inorg. film coated on the surface. The inorg. transparent coated film has many fine protrusions having 0.1-2.0mu height, and the resistivity of the surface is controlled to 10<6>-10<8>OMEGA.cm. Silicate glass such as silica glass, alkali silicate glass, soda-lime glass, potash-lime glass, and lead glass are essentially used as the inorg substrate. When the inorg. plate is used as the cathode-ray tube for a display, a transparent inorg. substrate is preferably used as the inorg. substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inorganic plate having antistatic properties and low reflectivity.

[Technical background of the invention and its problems] In recent years, a wide variety of devices that use cathode ray tubes for displays have been developed.

It started with computers and office automation equipment, and is now becoming widely used in ordinary households, including personal computers, word processors, and home automation.

A TV's cathode ray tube is viewed from a distance, but display cathode ray tubes are placed close to each other, and the surface is sometimes touched with a touch pen.The phenomenon in which the surface of the cathode ray tube is charged with static electricity, or electrification, has become a problem. .

This is because, for example, when the surface of a cathode ray tube is charged,
The charged surface attracts dust, making the display difficult to read, and if you touch it with a stylus, the discharge may cause dust to fly into your eyes, and if you accidentally come into contact with the surface of the cathode ray tube, you may receive a shock. Therefore, it was desired to prevent this.

Additionally, there is a theory that positive ions generated by the use of switches are harmful to the human body, and it is clear that preventing static electricity is effective in preventing the generation of such ions.

Generally, to prevent static electricity from building up on a board, increase the conductivity of the board to prevent static electricity from accumulating on the board.

It is necessary to gradually release static electricity.
Possible means for this include a method of making the substrate surface porous to contain moisture, or a method of forming a transparent conductive thin film on the substrate surface, but the former method is difficult to use because it is easily controlled by the environment.

On the other hand, as the conductive thin film formed on the surface of the substrate, S n O2, In2O3, CdO, Au, etc. have been used for a long time, and recently, L a B 6, tungsten bronze, etc. have also been used, but 5n02. In2O3 etc. are the most practical. Known methods for forming this conductive thin film include the CVO method and the high-frequency snottttering method, but even if these methods form a thin, transparent film, the surface specific resistance of the resulting conductive film is low. It is about 102Ω·ell.

By the way, in transparent inorganic plates used in cathode ray tubes for displays, if the surface resistivity is 1010 Ω・cm or more, it is completely impossible to prevent charging due to static electricity, whereas if this surface resistivity is 10 6 Ω・cm or less, the conductivity is poor. It was found that the height was too high and caused problems in the use of a touch pen as a display cathode ray tube.

Therefore, if a transparent conductive layer is formed on a transparent substrate using the conventional method, it cannot be used as a cathode ray tube for display purposes.

The present inventors have found that for display cathode ray tubes, it is most desirable for the specific resistance of the substrate surface to be approximately 10 to 1010 Ω·c11 in order to prevent static electricity.

Therefore, in order to use a conductive thin film for antistatic use in cathode ray tubes for displays, it was necessary to develop a film forming method that would increase the resistivity to 102 Ω·cm.

On the other hand, if external light rays are reflected on the surface of the cathode ray tube, the image becomes difficult to see, so it is desirable to reduce this reflection.

Conventionally, for this purpose, a corrosive chemical solution such as hydrofluoric acid was applied to an inorganic plate to form many fine irregularities on its surface. The use of chemical solutions is not desirable in terms of handling or pollution.

[Object of the Invention] The present invention aims to solve the problems associated with the prior art as described above, and provides a display device that can prevent charging and reduce reflection on the surface. The object is to provide an inorganic plate particularly suitable for use as a cathode ray tube.

[Summary of the Invention] The inorganic board according to the present invention has antistatic properties and low reflectivity, and has many fine ridges with a height of 0.1 to 2.0 μm on the surface of the inorganic board. It is characterized by being provided with a transparent inorganic coating having a surface resistivity of 10 -10 8 Ω·cm.

[Detailed Description of the Invention] The inorganic plate according to the present invention consists of an inorganic substrate and a transparent inorganic coating provided on the surface of the inorganic substrate, and the transparent inorganic coating has a height of 0.1 to 2.0 JLts. It has many fine ridges, and its surface has a specific resistance of 106 to 108 Ω・CS
It is characterized by having excellent antistatic properties and low reflectivity.

The inorganic base material used in the present invention is silicate glass (
quartz glass), alkali silicate glass.

Silicate glasses such as soda lime glass, potash lime glass, lead glass, barium glass, and borosilicate glass are mainly used, but are not limited to these.
For example, glasses such as phosphate glass, borate glass, sulfate glass, nitrate glass, carbonate glass, chloride glass, fluoride glass, etc. may also be used.

Any other thermally stable base material can be used as the base material in the present invention.

Note that when the inorganic plate according to the present invention is used as a cathode ray tube for display, it is preferable to use a transparent inorganic substrate as the inorganic substrate.

To form a transparent inorganic film on such an inorganic substrate,
The surface of this inorganic substrate has a height of 0.1 to 2. A solution A containing a metal alcoholade as a main component, such as ethyl silicate, which mainly contributes to forming a large number of fine ridges of OILm and reducing surface reflectivity, and a tin compound, which imparts conductivity to the surface of the inorganic substrate. Alternatively, it may be used in combination with solution B containing an indium compound. Solution A has organosilicon as its main component, but this solution A consists of dissolving a metal alcoholade such as ethyl silicate [5i(C2H50)4] in an alcohol solvent. An alcoholic solution of a metal alcoholade made of alcoholic acid is mainly used.
In addition, in order to adjust the thermal expansion coefficient or firing temperature of the resulting film, butylborate [B(C
,H,0)3], methylborate [B(OC1
43)3], sodium ethylate [NaOC2H5]
, sodium methylate [Na OCH3], lithium ethyl) [Li0CH1, aluminum propoxide [AI(QC3H7)31. An alcohol solution such as triethyl ethyl phosphate [PO(QC2)15)3] may be added to the ethyl silicate alcohol solution.

Further, for the purpose of adjusting the viscosity of the film-forming solution, an alcohol such as methanol, ethanol, propane, butanol, etc. is used in combination with the above-mentioned 7-alcohol solution.

The type of alcohol used influences the rate of hydrolysis of the metal alcoholade.

For example, when using methanol or ethanol, the rate of hydrolysis of the metal alcoholade is greater than when using propatool or butanol.
Therefore, it is preferable to select the alcohol to be used in consideration of the hydrolysis rate of the metal alcoholade.

As the hydrolysis 7A moderating agent, inorganic acids such as hydrochloric acid and nitric acid, or organic acids such as acetic acid can be used, and among these, hydrochloric acid is particularly preferred.

For example, in the case of 12N hydrochloric acid, the hydrolysis regulator is
0.5 to 2.0 g per 100 g of solution A. It is preferable to add the acid in an amount such that the acidity is 10 to 20 pp-. When using an acid as a hydrolysis regulator, if the amount of acid added is too small, the hydrolysis rate of the metal alcoholade will be reduced. is undesirable because it is too slow, and if the amount of acid added is too large, the hydrolysis rate of the metal alcoholade is too fast, gelation progresses too much, and the viscosity of solution A increases, making it difficult to coat, which is undesirable.

Solution A containing the above-mentioned components is hydrolyzed by moisture present in the air and turns into a gel.

Therefore, this hydrolysis progresses more easily as the humidity becomes higher and the temperature becomes higher, and furthermore, when the solution A is stirred, it progresses more easily.

Specifically, while considering the above conditions, the room temperature is 15 to 25
℃, relative humidity 30-60%, solution A at 2 min.
While stirring at about 00 to 800 rpm.

It is preferable to allow the hydrolysis reaction of the metal alcoholade to proceed gradually over time.

In this way, when the hydrolysis reaction of the metal alcoholade is allowed to proceed while stirring the solution A, gelation of the solution occurs, and the gel phase is destroyed by the stirring.
The fine gel phase and the gel phase become mixed.
In this state, if gelation is insufficient and the content of the gel phase is low, the number of fine protuberances that will be formed later on the non-molecular base material will be small and the height thereof will be low, which is not preferable.

On the other hand, if gelation progresses too much, the viscosity of solution A will increase excessively, making coating work difficult, which is not preferable.

Next, when the solution A obtained as described above is applied onto an inorganic substrate to form a film, a film with a height of 0.1 to
A large number of fine ridges of 2.01 Lm are formed to reduce surface reflectivity.

On the other hand, the solution B for imparting conductivity to the surface of the inorganic substrate contains a tin compound or an indium compound as described above.

These tin compounds, 6z, are indium compounds such as dimethyltin dichloride [(C13)29nCI21
, silver caprylate [(07H15COO)25nl, diisoamyloxyethoxyantimony ICHO・(C5H
1lO)2Sb].

Acetylacetonate indium [CH3(COCI(
2) 2.In] etc. are preferably used, and complex acids such as
Tin [Sn (CM Coo)], tin oxalate [Sn
((:00) 2], stannous tartrate [SnCH(OH
) (COO)21 etc. are also used.

It is known that the resistance value, etc. of these organometallic compounds can be stabilized by mixing small amounts of different metals, rather than when used alone. It is preferable to add a small amount of antimony or indium.

The amount added is in the range of 0.1 to 5.0%, and in that case, inorganic tin chloride (S n C+ 4 ) or indium chloride (InCIa) may be used.

Solution B can be prepared by dissolving these organometallic compounds in a solvent such as methanol, ethanol, propatool, butanol, acetylacetone, or the like.

By separately applying such solution A and solution B onto an inorganic substrate, it is possible to form a transparent inorganic coating having reduced surface reflectivity and excellent antistatic properties according to the present invention. The above-mentioned transparent inorganic coating can also be formed by using a mixture of solution A and solution B.

When mixing Solution A and Solution B, if a large amount of Solution B is used, the conductivity of the resulting transparent inorganic coating will be increased.

When applying solution A and solution B as described above, any type of application method that applies a liquid to a solid surface can be adopted, but immersion method, falling method, spray method, ultrasonic atomization method, etc. can be adopted.・Next, the 441 coated film is heated,
The coating is dried and fired.

The drying step and the firing step may be performed as a series of steps or may be performed as separate steps.

In the drying step of the film, preferably 100 to 130
It is sufficient to heat the applied film for about 10 to 50 minutes at °C,
In the firing step, the coated film may be heated at 250 to 400°C, preferably 350 to 390°C, for about 10 to 20 minutes.

Although controlling the heating temperature in the drying process is not very important, controlling the heating temperature in the firing process is important.

If the firing temperature is less than 250°C, the decomposition and oxidation of the organic metal in the applied film will be insufficient, and the film will easily peel off from the base material, which is not very preferable.

In this way, no 4I! A transparent inorganic coating with antistatic properties and low reflectivity is formed on the base layer, having many fine ridges of 0.1 to 2 degrees in height and a surface resistivity of 10 to 108 CII. Ru.

In the inorganic plate according to the present invention, the transparent inorganic coating has a protuberance with a height of 0.1 to 2.0 JL and a diameter of about 1 to 107 L intestine, but this protuberance has an amoeboid shape. Because it is amorphous, it varies over a wide range.

Furthermore, in this specification, an inorganic plate does not necessarily mean a plate-like one, but may have a bent shape, and in some cases, an article in which the plate grains have a single curved shape. may be formed.

[Example] The present invention will be explained below with reference to Examples.
However, the invention is not limited to the examples.

A face plate for a 6-inch color cathode ray tube having the following composition was used as a transparent inorganic base material.

S, 0:83% Tsuta2 AIO: 2% RO: 19% R20: 16% (RQ is an alkaline earth metal oxide such as CaG, SrQ, BaO, PbO, etc., and R20 is
, Na20, Li20 and other alkali metal oxides. ) In addition to the above, this base material also contains trace amounts of NiO and CO3.
Contains coloring metal oxides such as 0aCrO.

This base material is available as a glass plate for color cathode ray tubes.

The coefficient of thermal expansion of this base material is 911×10''/''C, the softening point is 890°C, and the annealing point is 500°C.

On the other hand, solution A having the following composition was prepared as follows.

Ethyl silicate 5% by weight Ethanol 35% by weight Isopropanol 20% by weight Butanol 40ffl Volume % Obtained solution l
Solution A was prepared by adding 0.911 g of 12N hydrochloric acid to the solution A.

Next, a solution B having the following composition was prepared which mainly imparts conductivity to the surface of the inorganic substrate.

Indium acetylacetonate 8% by weight dimethyltin dichloride 2% by weight acetylacetone
70% by weight butanol
20% by weight of solution A prepared as above was atomized onto the above inorganic base Murakami using a spray method, one large particle of the resulting atomized material was removed, and the solution was sprayed four times. . Next, a solution obtained by mixing approximately equal amounts of solution A and solution B was sprayed once in the same manner.

The resulting coating film was dried at 110°C±10°C for about 30 minutes, and then baked at 370°C±20°C for about 10 minutes.

The inorganic plate thus obtained has a height of 0.0 mm on its surface.
It had many fine ridges with a terminal layer of 1 to 2.0, and the specific resistance of its surface was 108 Ω·C.

Note that the surface specific resistance of the inorganic plate obtained after firing is lO8Ω.
・If it is smaller than cm, reduce the mixing ratio of solution B, and
If the resistivity is larger than 0.8Ω·C, the surface resistivity value can be adjusted by increasing the mixing ratio of solution B.

Further, it is preferable to constantly measure the specific resistance of the surface during the manufacturing process of the inorganic plate, and adjust the mixing ratio of solution A and solution B based on this measured value.

[Effects of the Invention] The inorganic plate according to the present invention has a height of 0.5 mm on the surface of the inorganic substrate.
It has a large number of fine ridges with a diameter of 1 to 10 JL layer, and the specific resistance of the surface is 106 to 1.
08Ω・C■, it has excellent antistatic properties and low reflectivity, and can be widely applied not only to display devices but also to windows, doll cases, watch cover glasses, etc.

Claims (1)

[Claims] (1) The surface of the inorganic substrate has many fine ridges with a height of 0.1 to 2.0 μm, and the specific resistance of the surface is 10
An inorganic plate having antistatic properties and low reflectivity, characterized by being provided with a transparent inorganic coating having a resistance of ^6 to 10^1^0 Ω·cm.