JPH08162018A - Shadow mask adopting electron reflecting film and its manufacture - Google Patents

Abstract

PURPOSE: To provide a shadow mask with an electron reflection layer, which is simply manufactured, easily applied and still greatly reduced in hole clogging (hole closure) and thermal deformation, and its manufacturing method. CONSTITUTION: A composition 5 containing 70 wt.% or more bismuth ammonium citrate solution with a bismuth content of 10-50 wt.% and remaining percent of an inorganic binder and air 6 are filled in an atomizer, and the composition 5 is sprayed through the nozzle of the atomizer in the form of aerosol 7 to form an electron reflection layer on the surface on the electron gun side of a shadow mask 2. In this case, an air distributor 8 is provided in front of the shadow mask 2 on the opposite side to the electron gun side to distribute air when the composition 5 is sprayed, so that the shadow mask 2 can be greatly reduced in hole closure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shadow mask having an electron reflection film and a method of manufacturing the same, and more particularly to a shadow mask having an electron reflection film having an excellent anti-doming effect and a method of manufacturing the same.

[0002]

2. Description of the Related Art A shadow mask in a color cathode ray tube, which is also called a color selection electrode, has a structure in which a large number of holes having a constant thickness are arranged at a constant thickness and is provided between a fluorescent film and an electron gun. By selectively passing only the desired electron beam among the electron beams emitted from the electron gun through the large number of holes, the phosphors of each color formed on the upper part of the panel are selected by the passing electron beam. It is a component that emits red light and emits red, green, and blue colors to embody the colors of a reproduced image.

In such a shadow mask, when the electron beam is emitted toward the shadow mask, electrons other than the electrons passing through the holes of the shadow mask collide with the shadow mask, and the colliding electrons cause the collision. The temperature of the shadow mask rises to about 80 to 90 ° C., and the generated heat causes the shadow mask to thermally expand, causing a thermal deformation phenomenon in which the central portion of the shadow mask expands.

When this so-called doming phenomenon, which is a thermal deformation phenomenon, occurs, the hole of the shadow mask is slightly moved from the desired position, and an electron beam which is not desired to pass through the hole separated from the original position passes therethrough. However, the phosphor that is not desired to emit light is caused to emit light, and as a result, the color purity of the reproduced image is reduced.

By the way, the phenomenon of deterioration in color purity due to the thermal deformation of the shadow mask appears as a serious phenomenon as the size of the color cathode ray tube becomes larger and the definition thereof becomes higher. , 1 for industrial use
A special shadow mask is used in a cathode ray tube of 5 ″ or larger. In the case of such a shadow mask, a material having a high electron reflectance such as bismuth is coated on the surface of the electron gun side AK (Aluminum). Killed) mask is used, or it is expensive and not easy to process, weld, and handle, but it has a low coefficient of thermal expansion.
The thermal deformation rate is reduced by using sk).

FIG. 1 shows an enlarged sectional view of a shadow mask 2 mounted inside a panel 1 having a fluorescent film formed on its inner surface.

On the surface of the electron gun side, an electron reflection film 3 capable of reflecting the electrons colliding with the shadow mask is coated and formed. Generally, the shadow mask coated with the electron reflection film is as follows. It is manufactured by the method.

First, fine powder of a metal oxide having an average particle size of about 1 μm or less, such as bismuth, lead and tungsten, having a high electron reflectance is mixed with water, water glass, a dispersant, a surfactant and the like. Prepared as a suspension.

Next, this suspension is sprayed onto the surface of the shadow mask and then dried to form an electron-reflecting film (see Korean Patent Publication No. 91-5092).

As a result, the metal oxide becomes fine particles and remains on the electron reflection film, which is about 20 to 30.
It is known to bring about a% doming prevention effect.

[0011]

However, according to the above-mentioned conventional method for manufacturing a shadow mask using an electron reflection film, it is difficult to disperse the powder for electron emission in the liquid, and the average particle diameter is 1 μm. Even if the following fine powders are used, aggregates are easily formed, and the spray nozzle easily vibrates during spraying, which not only makes uniform spraying difficult, but also produces a shadow mask in which many holes are blocked. There was a problem.

Therefore, in the case of an industrial cathode ray tube having a fine mask hole (about 120 μm), this method can hardly be applied in reality, and there are various problems as described above, so that it is large. Alternatively, it has been a reality to use an amber mask for a high-definition cathode ray tube, which is expensive and is not easy to process, weld, and handle, but has a small coefficient of thermal expansion and a small thermal deformation rate due to collision with electrons.

The present invention has been made in view of the above problems, and substantially eliminates the difficulty of dispersing the powder for electron emission and the hole closing that occurs when such a powder is coated on the shadow mask. While being able to
To provide a method for producing a shadow mask that employs an electron reflection film that can be applied to a fine industrial cathode ray tube, and a shadow mask that employs an electron reflection film that is excellent in the doming reduction effect produced by this production method. To aim.

[0014]

The object of the present invention is to prepare a bismuth ammonium citrate solution having a bismuth content of 10 to 50% by weight, and to add an inorganic binder to the bismuth ammonium citrate solution. And a step of spraying the composition of the electron-reflecting film manufactured in the step in the direction of the electron gun of the shadow mask, applying the composition, and then selectively heat-treating the composition. This is achieved by a method of manufacturing a shadow mask using an electron reflection film, and a shadow mask manufactured by the manufacturing method.

[0015]

In the present invention, of the electron-reflecting substances having a high electron reflectance, a bismuth compound having particularly excellent electron-reflecting properties is produced in a solution state, and an electron-reflecting film is formed which is applied to a shadow mask. . That is, it is a method for solving the above-mentioned problems by the conventional method for producing an electron reflection film, which uses a suspension obtained by dispersing fine powder in a liquid, and in the present invention, the main component of the electron reflection film composition is used. By producing and utilizing a solution containing bismuth which is
A good electron reflective film can be formed on the shadow mask.

As a method of spraying the manufactured solution on one surface of the shadow mask, there are a general spray method, an atomizer method, an ultrasonic atomizer method, and the like.

[0017]

EXAMPLES Examples of a shadow mask manufacturing method using the electron reflection film according to the present invention and a shadow mask manufactured by the manufacturing method will be specifically described below.

Explaining the method of manufacturing the shadow mask using the electron reflection film according to the present invention, first, a bismuth ammonium citrate solution having a bismuth content of 10 to 50% by weight is prepared, and an inorganic binder is added thereto. A composition of an electron reflection film is prepared. At this time, the bismuth ammonium citrate solution of the composition is 70% or more based on the total composition.

In the composition of the electron reflection film thus produced, bismuth having excellent electron reflection characteristics is dissolved in a salt form. Therefore, unlike a suspension in which bismuth, lead, tungsten, or a mixture thereof is all dispersed, the composition of the electron reflective film used in the present invention has a property close to that of a solution, which makes ejection extremely easy. .

FIG. 2 shows a step of forming the electron reflection film on the surface of the shadow mask 2 by spraying the composition of the electron reflection film thus prepared by using an atomizer.

In this case, as shown in FIG. 2, the composition 5 containing the substance having the electron reflection property and the air 6 are used.
To the atomizer, and the composition 5 is sprayed in the form of an aerosol 7 through the nozzle 4 of the atomizer.

Then, the composition 5 is applied to the surface of the shadow mask 2 on the electron gun side.

At this time, an air distribution device 8 is provided on the front surface of the shadow mask 2 on the side opposite to the electron gun side so that the air distribution is blown while the composition 5 is being sprayed. The so-called hole closure, in which the holes are blocked, can be greatly reduced.

FIG. 3 shows a method of forming an electron reflection film using the ultrasonic atomizer 9.

In this case, as shown in FIG. 3, a composition 5 containing a substance having an electron-reflecting property is added to an ultrasonic atomizer 9 to generate an aerosol, and this is used as a shadow mask 2.
The surface of is coated to form an electron-reflecting film.

Also in this case, it is desirable that the air distribution device 8 is provided on the front surface of the shadow mask 2 so that the air distribution is blown during the jetting to reduce the hole closing of the shadow mask 2.

FIG. 4 shows a method of simultaneously spraying 5 to 10% water glass when the composition 5 of the electron reflective film is sprayed to form the electron reflective film on the surface of the shadow mask 2.

That is, as shown in FIG. 2, a composition 5 containing a substance having an electron reflection characteristic and air 6 are added to an atomizer, and the composition of the electron reflection film is applied to the shadow mask 2 through a nozzle 4 of the atomizer. In the process of spraying on the surface in the electron gun direction, 5% to 10% of the water is added to the water glass 10 in the same manner as in the case of the composition 5, and at the same time as the composition 5 of the electron reflection film is sprayed, 5% to 10% thereof is sprayed. Water glass 1
0 is jetted from the nozzle 4.

After coating the surface of the shadow mask 2 with the electron-reflecting material in this manner, preferably about 40
The heat treatment is performed at a temperature of about 0 ° C. to oxidize the electron-reflecting material to complete the electron-reflecting film. In addition, since heat of about 450 ° C. is applied during frit sealing for sealing the panel and the funnel during manufacturing of the cathode ray tube, the above heat treatment need not be performed separately.

As a result of repeated experiments by the present inventor, it was confirmed that the thicker the film thickness of the electron reflection film, the better the electron reflection effect. Therefore, in order to form a thick film, the above-mentioned solution injection was performed. The steps may be repeated.

The total thickness of the electron reflection film is not particularly limited, but 0.1-20 μm is desirable in view of the electron reflection effect and efficiency provided by the film.

Further, as a result of examining the formed electron-reflecting film, it was confirmed that the size of the particles formed on the film was extremely fine and was in the range of 0.01 to 1 μm on average. It was found that, unlike the electron-reflecting film manufactured by using the suspension, it appeared as a network structure rather than a particle morphology, and that the structure was firm.

FIG. 5 (a) shows a SEM photograph of the structure of the electron reflecting film by the conventional method, and FIG. 5 (b) shows a SEM photograph of the structure of the electron reflecting film by the method of the present invention described above. .

Comparing the photographs of FIG. 5 (a) and FIG. 5 (b), the electron reflection film produced by the conventional method shown in FIG. 5 (a) was manufactured by the present invention shown in FIG. 5 (b). The electron reflection film is formed in a net structure, and the reason is as follows.

That is, since the composition of the conventional electron-reflecting film is a suspension, it is not finely coated on the shadow mask, but the composition of the electron-reflecting film used in the present invention has a property close to that of a solution. This is because the objects are finely applied without being entangled with each other.

Therefore, as can be seen from the comparison between FIG. 5A and FIG. 5B, the shadow mask using the electron reflection film manufactured according to the present invention has a fine structure and thus has a further excellent electron reflection characteristic. I understand that.

Hereinafter, preferred embodiments 1 to 3 of the shadow matrix according to the present invention manufactured by the above manufacturing method will be described in detail.

(Example 1) First, 20 g of citric acid was dissolved in 10 g of 10% by weight aqueous ammonia at room temperature.

Next, 40 g of bismuth nitrate pentahydrate [Bi (NO3) 5H2O] was added to the obtained solution to dissolve it, and 10% by weight of aqueous ammonia was gradually added to this to obtain a solution of p.
It was adjusted to about H7. Next, silane (NUC, A-
1120) 2g was added to the said solution, and the electron reflective film composition was obtained.

Further, the electron-reflecting film composition thus obtained is put into an atomizer, air is added, and the composition is sprayed into an aerosol state through a nozzle of the atomizer.
Coat on AK mask for 14 "0.28D CRT.

During the spraying of the composition, an air distribution device is provided on the front surface opposite to the surface to be coated with the shadow mask so that the air distribution is blown.
A shadow mask employing an electron reflection film was manufactured by performing heat treatment at the temperature.

Then, using the shadow mask manufactured according to the first embodiment, the thermal drift amount of electrons for grasping the doming prevention effect was measured.

As a result, it was found that the amount was reduced by about 40% as compared with the case where the shadow mask formed with the electron reflection film according to the conventional powder spray method is applied. This means an improvement in color purity and image quality.

Example 2 First, 1 g of citric acid was added to 10 g of water.
0 g was dissolved at room temperature.

Next, 20 g of bismuth nitrate pentahydrate was added to and dissolved in the obtained solution, and 28% by weight of aqueous ammonia was gradually added to adjust the pH to 7. To the solution thus obtained, 1.5 g of silane was added to obtain a composition for an electron reflection film.

Then, after the shadow mask using the electron reflection film was manufactured by the same method as in Example 1, the effect of preventing doming was grasped.

As a result, it was confirmed that the doming amount was reduced by 32% as compared with the case where a shadow mask having an electron reflection film formed according to the conventional powder spray method was applied.

Example 3 A shadow mask employing an electron reflecting film is manufactured by the same method as in Example 2. In this Example 3, however, as shown in FIG. Is sprayed onto the surface of the shadow mask 2 on the electron gun side, simultaneously with the spraying of the composition 5, 7% water glass 10 is sprayed on the surface of the shadow mask 2 on the electron gun side.

Then, by grasping the doming prevention effect,
It was confirmed that the doming amount was reduced by 45% as compared with the case where the shadow mask having the electron reflection film formed by the conventional powder spray method was applied. That is, by the simultaneous injection of 7% water glass 10 in this Example 3,
From the case of a 32% reduction in the amount of doming according to Example 2,
I know it is excellent.

[0050]

As described above, the shadow mask having the electron-reflecting film manufactured by the manufacturing method according to the present invention has a bismuth having an excellent electron-reflecting property among electron-reflecting substances having a high electron-reflecting rate. Since the compound is manufactured in a solution state and applied to a shadow mask to form an electron-reflecting film, thermal deformation compared to a shadow mask having an electron-reflecting film manufactured by a conventional powder-type spray method. The rate can be greatly reduced.

Further, the hole closing of the shadow mask is greatly reduced during the manufacturing process, and the AK mask can be applied to a large-scale or high-definition cathode ray tube.

Therefore, the shadow mask of the present invention can replace the amber mask used as the shadow mask of the cathode ray tube for industrial use, which greatly contributes to cost reduction.

Further, in the present invention, since the electron reflecting film is produced by the method of injecting a composition close to a solution component instead of a suspension, the process is extremely simple and can be easily applied to a production line. There is.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an enlarged cross-sectional view of a shadow mask on which an electron reflection film is formed.

FIG. 2 is an explanatory view illustrating a process of forming an electron reflection film on the surface of a shadow mask using an atomizer according to an embodiment of the shadow mask manufacturing method of the present invention.

FIG. 3 is a schematic view illustrating a process of forming an electron reflection film on a surface of a shadow mask using an ultrasonic atomizer according to another embodiment of the shadow mask manufacturing method of the present invention.

FIG. 4 is a schematic view illustrating a process of forming an electron reflection film on a surface of a shadow mask using two atomizers according to another embodiment of the shadow mask manufacturing method of the present invention.

5A is a SEM photograph showing a structure of an electron reflecting film by a conventional method, and FIG. 5B is a SEM photograph showing a structure of an electron reflecting film by the method of the present invention.

[Explanation of symbols]

 1 Panel 2 Shadow Mask 3 Electron Reflective Film 4 Nozzle 5 Composition 6 Air 7 Aerosol 8 Air Distributor 9 Ultrasonic Sprayer 10 7% Water Glass

Claims (10)

[Claims] 1. A step of preparing a bismuth ammonium citrate solution having a bismuth content of 10 to 50% by weight, and a step of preparing an electron reflective film composition by adding an inorganic binder to the bismuth ammonium citrate solution. And a step of selectively applying heat treatment to the surface of the shadow mask in the direction of the electron gun of the shadow mask, spraying the composition of the electron reflective film manufactured in the above step, and applying the heat treatment. Of manufacturing shadow mask. 2. The method of manufacturing a shadow mask using an electron reflection film according to claim 1, wherein the inorganic binder is silane. 3. The method of claim 1, wherein the bismuth ammonium citrate solution has a weight of 70% or more with respect to the total electronic composition. 4. The method according to claim 1, wherein the spraying is performed using an atomizer nozzle. 5. The method of claim 1, wherein the spraying is performed using an ultrasonic sprayer. 6. The method of manufacturing a shadow mask using an electron reflective film according to claim 1, wherein air is blown on the front surface of the shadow mask while the composition of the electron reflective film is sprayed. Method. 7. In the process of spraying the composition of the electron-reflecting film onto the surface of the shadow mask in the direction of the electron gun, 5-1.
The method for producing a shadow mask using an electron reflection film according to claim 1, wherein 0% water glass is sprayed at the same time. 8. A shadow mask using an electron reflection film, which is manufactured by the method according to any one of claims 1 to 7. 9. A shadow mask using an electron reflection film according to claim 8, wherein particles having an average diameter of 0.01 to 1 μm are formed in a net structure. 10. The shadow mask adopting the electron reflection film according to claim 8, wherein the shadow mask has a thickness of 0.1 to 20 μm.