KR100428967B1 - Cathode ray tube and method for manufacturing the same including steps of depositing first and second compounds and grounding copper tape - Google Patents

Abstract

PURPOSE: A cathode ray tube and a method for manufacturing the same are provided to effectively shield electromagnetic waves by forming a low resistant transparent conductive film on a panel and controlling material and length of a grounding tape. CONSTITUTION: A method for manufacturing a cathode ray tube comprises a step of depositing a first compound on a panel(31) of a cathode ray tube, wherein the first compound contains transparent conductive particle selected from a group composed of tin containing indium oxide, indium oxide titanium, tin oxide, titanium oxide, antimony oxide, and a solvent; a step of forming a transparent conductive film by depositing a second compound on the resultant structure, wherein the second compound contains metal alkoxide(M1(OR)4), metal(M2) micro particle or metal salt containing metal micro particle, catalyst and solvent, and drying and heat treating the resultant structure; and a step of grounding a copper tape(35) between a band(34) and the panel of cathode ray tube where the transparent conductive film is formed.

Description

Cathode ray tube and its manufacturing method

The present invention relates to a cathode ray tube and a method for manufacturing the same, and more particularly, to a cathode ray tube having an electromagnetic wave shielding film having excellent electromagnetic wave blocking effect and a method of manufacturing the same at a low manufacturing cost.

Typically, the color cathode ray tube is a panel 10 in which the fluorescent film 11 is formed on an inner surface thereof, as shown in FIG. 1, and is installed to be spaced apart from the fluorescent film 11 by a predetermined distance inside the panel 10. 12) and a shadow mask frame assembly 14 composed of a frame 13 supporting the same, and an electron gun 16 enclosed in the neck portion 15 and enclosed in the neck portion 15 so as to be sealed to the panel 10. It is comprised with the funnel 18 in which the deflection yoke 17 was provided.

The color cathode ray tube configured as described above passes the electron beam of the shadow mask 12 having the color discrimination function by selectively deflecting the electron beam emitted from the electron gun 16 mounted on the neck portion 15 by the deflection yoke 17. It passes through the ball and lands at each fluorescent point of the fluorescent film 11 to form an image.

However, since the screen surface of the panel 12 for reproducing the image is a smooth glass surface and the light incident from the surroundings is specularly reflected, the phenomenon that the luminance of the screen formed by the emission of the fluorescent film 13 is relatively lowered appears. . That is, when external light is incident on the outer surface of the panel, afterimages are generated on the outer surface of the panel by the external light, so that the reproduced screen and the afterimage overlap and the luminance and the resolution of the screen are reduced.

In addition, since the electron beam, that is, the beam current collides with the outer surface of the panel 10, charges are accumulated during and after the operation of the cathode ray tube. Accordingly, not only dust, etc. are attached to the outer surface of the panel, but also an electric shock when the operator comes in contact with it, so that special measures for antistatic are required. Therefore, it is common to form an antistatic film on the cathode ray tube panel 10.

Meanwhile, since it has been reported that electromagnetic waves emitted from devices such as monitors have a very harmful effect on the human body, regulations on electromagnetic waves are gradually being tightened. In other words, the electromagnetic waves generated by the monitor are regulated by the standard set by the Swedish Confederation of Professional Employees (TCO). Therefore, researches are being actively conducted to reduce the electromagnetic waves in order to obtain cathode ray tubes that can respond to TCO regulations.

As one method of reducing electromagnetic waves, there is a method of forming a transparent conductive film having a predetermined resistance value on the surface of the cathode ray tube panel.

The transparent conductive film is generally manufactured using a sputtering method, a vapor deposition method, an ion beam method, or the like. The transparent conductive film formed according to this method is generally excellent in its general characteristics, but it requires expensive equipment such as a vacuum device during the manufacturing process, which is expensive to manufacture and must be fired at a high temperature of 400 ° C. or higher. Therefore, the transparent conductive film prepared according to this method is practically unsuitable for application as an electromagnetic shielding film of a display device, especially a cathode ray tube, which needs to be fired at a temperature as low as 200 ° C. and requires a low manufacturing cost.

Another method of reducing electromagnetic waves is to separately install a reverse pulse circuit for reducing electromagnetic waves in the monitor circuit. However, this method has the following problems.

First, since the manufacturing process for installing the reverse pulse circuit is added by one step, the manufacturing process increases, thereby increasing the manufacturing cost.

Second, because the circuits are slightly different for each monitor, electromagnetic shielding power is not constant.

The amount of electromagnetic waves generated by the monitor generally varies depending on the resistance of the cathode ray tube panel surface, the kind of material (ground tape) grounding the panel surface and the band, and the length of the ground tape.

Accordingly, the present inventors have made a lot of research to produce a cathode ray tube having excellent electromagnetic shielding power at a low processing cost by appropriately adjusting the above factors.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a method of manufacturing a cathode ray tube that can effectively block electromagnetic waves by forming a transparent conductive film having a low resistance on a panel and controlling grounding material and length.

Another technical object of the present invention is to provide a cathode ray tube formed according to the above method.

1 is a view showing the structure of a typical cathode ray tube,

2 is a view schematically showing the structure of a transparent conductive film according to the present invention,

3 is a view schematically showing the structure of a cathode ray tube with a ground tape attached thereto.

<Explanation of symbols for the main parts of the drawings>

10, 21, 31 ... Panel 12 ... Shadow Mask

13 ... frame 14 ... shadow mask frame assembly

15 ... Neck 16. Gun

17 ... deflection yoke 18 ... funnel

19 ... cone part 22 ... transparent conductive particles

23 Hydrolysis Products of Metal Alkoxides (Metal Oxides)

24 ... metal particles

32 ... Panel invalid screen 33 ... Panel valid screen

34 ... band 35 ... ground tape

The first object of the present invention is the step of (a) applying a first composition comprising a transparent conductive particles and a solvent on top of the panel of the cathode ray tube; (b) Applying a second composition containing a metal alkoxide (M ₁ (OR) ₄ ), metal (M ₂ ) fine particles or metal salt (M ₂ X) containing the metal fine particles, a catalyst and a solvent on the resultant product. And drying, followed by heat treatment to form a transparent conductive film; And (c) grounding the copper tape between the cathode ray tube panel and the band on which the transparent conductive film is formed.

The second object of the present invention is made by a cathode ray tube, characterized in that manufactured according to the above method.

The present invention is to obtain a cathode ray tube satisfying the TCO standard by optimizing the grounding tape material and the length of grounding the panel and the band while minimizing the resistance of the transparent conductive film formed on the panel surface.

Hereinafter, a method of manufacturing a cathode ray tube according to the present invention will be described.

First, a first composition containing transparent conductive particles and a solvent is coated on a cathode ray tube panel. At this time, it is preferable to rotate the cathode ray tube at a predetermined rotation speed in order to uniformly apply the composition on the panel. Then, the drying step may be performed or the drying process may be omitted.

Here, as the transparent conductive particles, metal oxides such as tin-containing indium oxide, indium titanium oxide, tin oxide, titanium oxide, and antimony oxide are used, and the particle size of the transparent conductive particles is 50 in order to prevent deterioration of the brightness and resolution of the cathode ray tube. It is suitably in the range from 150 nm to 150 nm, and in particular, in consideration of the production of dispersed transparent conductive particles and the stability of the coating process, 50 to 120 nm is preferable.

As a solvent, organic solvents, such as alcohol, a ketone, ester, or pure water are used. Herein, the concentration of the transparent fine particles with respect to the solvent is preferably 0.5 to 5.0% by weight, because the coating property is excellent when the concentration is in this range.

Subsequently, a second composition containing a metal alkoxide (M ₁ (OR) ₄ ), metal (M ₂ ) fine particles or metal salt (M ₂ X) containing the metal fine particles, a catalyst and a solvent is prepared. The second composition may further include a reducing agent. In this case, the reducing agent is selected from NaBH ₄ , SnCl ₂ , glycols, and ketones, and the content is 1 × 10 ⁻⁴ to 8 × 10 ⁻² mol% based on the metal alkoxide.

The second composition is applied onto a panel coated with the first composition, and then heat-treated at 160 to 300 ° C., preferably at 180 to 200 ° C. for 30 to 60 minutes. Then, by firing, a transparent conductive film as shown in FIG. 2 is formed on the cathode ray tube panel.

In this case, reference numeral 21 denotes a panel, reference numeral 22 denotes transparent conductive particles, reference numeral 23 denotes a hydrolysis product (metal oxide) of a metal alkoxide, and reference numeral 24 denotes metal fine particles. It can be seen that the metal fine particles 24 are present in the gaps between the livers. As a result, such a transparent conductive film is very excellent in conductivity.

The metal alkoxide is Si (OR) ₄ , Ti (OR) ₄ , Sn (OR) ₄ and Zr (OR) ₄ as (M ₁ (OR) ₄ ), wherein R is an alkyl group having 1 to 4 carbon atoms. One selected from among them is used, and silicon alkoxide is most preferred. As examples of the silicon alkoxide, tetramethyl silicate, tetraethyl silicate, tetrapropyl silicate, tetrabutyl silicate and their polymers or respective alkyltrialkoxy silanes can be used. At this time, the concentration of the silicon alkoxide to the solvent is preferably 0.5 to 5.0% by weight.

Metal (M ₂ ) fine particles use a metal selected from the group consisting of Ag, Au, Pt, Cu, Ni, Pb, Co, Rh, Ru and Sn, among which Au, Ag and Pt are stable to oxygen in the air. desirable.

It is suitable that the particle diameter of the said metal fine particle is 5-90 nm. If the particle size of the metal fine particles is less than 5 nm, the conductivity is insufficient, and if the particle size exceeds 90 nm, the transparency is lowered, which is not preferable.

As metal salts (M ₂ X), metal chlorides, nitrates, sulfonates, and the like are used, and any solvents such as water, alcohols, ketones, and esters can be used and are not particularly limited.

The mixed molar ratio between the metal fine particles (M ₂ ) and the metal alkoxide (M ₁ (OR) ₄ ) or the metal (M ₁ ) of the metal salt (M ₂ X) of the metal (M ₂ ) and the metal alkoxide (M ₁ (OR) ₄ ) ), The mixing molar ratio between the metals (M ₁ ) is preferably 0.01: 1 to 0.2: 1. If the molar ratio between the metal (M ₂ ) and the metal (M ₁ ) is less than 0.01: 1, the effect of improving conductivity is insufficient, and when the molar ratio between the metal (M ₂ ) and the metal (M ₁ ) exceeds 0.2: 1, transparency This is considerably lowered, the film strength is lowered and there is no practical use.

The catalyst serves to promote the hydrolysis reaction of the metal alkoxide, and an acid such as hydrochloric acid, nitric acid or the like is used. At this time, the content of the catalyst is 0.01 to 0.04 mol% based on the metal alkoxide.

The copper tape is grounded between the panel and the band on which the transparent conductive film is formed on the outer surface. This ground state is shown in FIG.

Referring to this, a transparent conductive film (not shown) is formed on the effective screen 33 and the invalid screen 32 of the cathode ray tube panel 31. The copper tape 35 is grounded between the transparent conductive film and the band 34.

The length l of the ground tape is appropriately adjusted according to the resistance of the transparent conductive film. In other words, if the resistance of the transparent conductive film is larger than the predetermined value, the length of the grounding tape may be increased. If the resistance is low and the conductivity is good, the length of the grounding tape may be shortened.

In the TCD, as shown in Table 1 below, the electric field and the magnetic field are divided into band I (BAND I: 5 Hz to 2 kHz) and band II (BAND II: 2 to 400 kHz). At this time, the electromagnetic wave was measured about 30cm away from the monitor.

TABLE 1

However, according to the present invention, the shielding effect of the electromagnetic waves is very excellent not only in other areas but also in the above areas.

Among the items described above, the most difficult area for electromagnetic shielding is the band II region of the electric field. Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not necessarily limited thereto.

<Example 1>

1.5 g of tin-doped indium oxide fine particles (hereinafter referred to as ITO) having an average particle diameter of about 80 nm was dispersed in a mixed solvent of 20 g of methanol, 67.5 g of ethanol, and 10 g of n-butanol to prepare a first composition (coating solution A). It was.

4.5 g of tetraethyl orthosilicate is mixed with a mixed solvent of 30 g of methanol, 50 g of ethanol, 12 g of n-butanol and 4 g of pure water, to which 0.6 g of nitric acid and 0.3 g of silver nitrate (AgNO ₃ ) are added and at room temperature Stirred for 24 hours to prepare a second composition (coating solution B).

While rotating the cathode-ray tube for the clean washing ^〃 monitor 17 to about 90rpm poured into the coating solution A was raised 50㏄ the rotation speed of the glass substrate at about 150rpm. Then, 60 ml of coating liquid B was poured and applied in the same manner as coating liquid A. Subsequently, the resultant was dried and then fired at 200 ° C. for about 1 hour to form a transparent conductive film.

In the cathode ray tube in which the transparent conductive film was formed, the monitor was manufactured by grounding the invalid screen and the band surface of the panel with copper tape.

<Example 2>

3.0 g of tin-doped indium oxide fine particles (hereinafter referred to as ITO) having a particle size of about 80 nm was dispersed in a mixed solvent of 20 g of methanol, 67.5 g of ethanol, and 10 g of n-butanol to prepare a first composition (coating solution A). .

4.5 g of tetraethyl orthosilicate is mixed with a mixed solvent of 30 g of methanol, 30 g of ethanol, 12 g of n-butanol, and 4 g of pure water, to which 0.5 g of nitric acid and chlorocauric acid (HAuCl ₄ · 4H ₂ O) are added. 0.2 g was added and stirred at room temperature for about 30 hours to prepare a second composition (coating solution B).

While rotating the cathode-ray tube for the clean washing ^〃 monitor 17 to about 90rpm poured into the coating solution A was raised 50㏄ the rotation speed of the glass substrate at about 150rpm. Then, 60 ml of coating liquid B was poured and applied in the same manner as coating liquid A. Subsequently, the resultant was dried and then fired at 250 ° C. for about 1 hour to form a transparent conductive film.

In the cathode ray tube in which the transparent conductive film was formed, the monitor was manufactured by grounding the invalid screen and the band surface of the panel with copper tape.

<Example 3>

It carried out according to the method similar to Example 1 except the composition of the coating liquid A and its manufacturing method are different.

1.g of tin-doped indium oxide fine particles (hereinafter referred to as ITO) having a particle size of about 80 nm was dispersed in a mixed solvent of 20 g of methanol, 67.5 g of ethanol, and 10 g of n-butanol to prepare a first composition (coating solution A). It was.

<Example 4>

The same procedure as in Example 1 was carried out except that silver nitrate was not added in the composition of the coating solution B.

Example 5

The coating solution B was prepared in the same manner as in Example 1, except that 0.001 g of NaBH ₄ , a reducing agent, was further added.

<Comparative Example 1-5>

The same procedure as in Example 1-5 was carried out except that aluminum tape was used instead of copper tape as the ground tape.

Comparative Example 6

The coating solution B was prepared in the same manner as in Example 1, except that 0.036 g of silver nitrate was used.

Comparative Example 7

At the time of preparation of Coating Liquid B. The same procedure as in Example 1 was conducted except that 0.73 g of silver nitrate was used.

In the cathode ray tube manufactured according to Example 1-5 and Comparative Example 1-7, the surface resistance and the electric field generation of the panel were measured, and the results are shown in Table 2 below. At this time, the electromagnetic wave was measured in the band II region by COMBINOVA EFM 200 at a position 30 cm away from the monitor.

TABLE 2

As can be seen in Table 2, the cathode ray tube manufactured according to Example 1-5 showed a small surface resistance and a small field generation rate.

On the other hand, the cathode ray tube manufactured according to Comparative Example 1-5 using aluminum tape as the grounding tape had a higher electromagnetic wave generation rate than that of Example 1-5 using copper tape as the grounding tape. It was found that the grounding effect is excellent. In addition, the cathode ray tube manufactured according to Comparative Example 6-7 had poor surface resistance, and the electric field generation frequency was 1.50 to 2.15 V / m.

According to the present invention, it is possible to manufacture a cathode ray tube capable of shielding electromagnetic waves below the TCO standard at a low manufacturing cost without using expensive equipment such as a sputtering apparatus.

Claims (14)

(a) applying a first composition comprising a transparent conductive particle selected from tin-containing indium oxide, indium titanium oxide, tin oxide, titanium oxide, and antimony oxide and a solvent on the panel of the cathode ray tube; (b) Applying a second composition containing a metal alkoxide (M ₁ (OR) ₄ ), metal (M ₂ ) fine particles or metal salt (M ₂ X) containing the metal fine particles, a catalyst and a solvent on the resultant product. And drying, followed by heat treatment to form a transparent conductive film; And (c) grounding the copper tape between the cathode ray tube panel and the band on which the transparent conductive film is formed; The metal alkoxide (M ₁ (OR) ₄ ) of the second composition is Si (OR) ₄ , Ti (OR) ₄ , Sn (OR) 4 and Zr (OR) ₄ , wherein R is 1 to 4 carbon atoms. Alkyl group), The metal (M ₂ ) and the fine particles of the second composition are silver (Ag), gold (Au), platinum (Pt), copper (Cu), nickel (Ni), lead (Pb), cobalt (Co), and rhodium ( Rh), ruthenium (Ru) and tin (Sn), The metal salt of the second composition (M ₂ X) is silver (Ag), gold (Au), platinum (Pt), copper (Cu), nickel (Ni), lead (Pb), cobalt (Co), rhodium (Rh) ), A ruthenium (Ru) and tin (Sn), a method for producing a cathode ray tube, characterized in that it is selected from the group consisting of metal chlorides, nitrates and sulfonates. The method of claim 1, wherein the second composition further comprises a reducing agent selected from the group consisting of NaBH ₄ , SnCl ₂ , glycols and ketones. The method of claim 2, wherein the content of the reducing agent is 1 × 10 ^-4 to 8 × 10 ^-2 mol% based on the metal alkoxide. The method of claim 1, wherein the heat treatment is carried out at 160 to 300 ℃ in step (b). The cathode ray tube manufacturing method according to claim 1, wherein a particle diameter of the transparent conductive particles in the first composition is 5 to 120 nm. 2. The mixed molar ratio between the metal fine particles (M ₂ ) and the metal alkoxide (M ₁ (OR) ₄ ) or the metal (M ₁ ) of the metal salt (M ₂ X) of the metal (M ₂ ) and the metal alkoxide ( A method for producing a cathode ray tube, characterized in that the molar ratio between the metal (M ₁ ) of M ₁ (OR) ₄ ) is 0.01: 1 to 0.2: 1. The cathode ray tube manufacturing method according to claim 1, wherein the metal (M ₂ ) fine particles have a particle diameter of 5 to 90 nm. The method of manufacturing a cathode ray tube according to claim 1, wherein after applying the first composition in the step (a), a drying process is performed. The method of claim 1, wherein the concentration of the transparent conductive particles to the solvent in the step (a) is a method for producing a cathode ray tube, characterized in that 0.5 to 5.0% by weight. The method of claim 1, wherein the concentration of the metal alkoxide to the solvent in the step (b) is 0.5 to 5.0% by weight manufacturing method of a cathode ray tube. The method according to claim 1, wherein the metal salt (M ₂ X) of the second composition is selected from the group consisting of metal chlorides, nitrates and sulfonates. The method of manufacturing a cathode ray tube according to claim 1, wherein the catalyst is an acid selected from the group consisting of hydrochloric acid and nitric acid. The method of claim 1, wherein the content of the catalyst is 0.01 to 0.04 mol% based on the metal alkoxide. Claims 1, 2, 3, 4, 5 to 13, characterized in that the cathode ray tube manufactured according to any one of claims.