JPH09213244A - Panel for cathode-ray tube and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To earth the electric charge charged on the conductive membrane in a multilayer membrane, and to form an electrode for earthing easily, by providing an electrode for earthing which is formed by applying a glass paste including a metal powder on an insulating membrane, and heating and baking it. SOLUTION: On the outer surface of a panel glass 10, a multilayer membrane 11 in order to give a conductivity and a reflection preventive property is formed. The multilayer membrane 11 has a conductive membrane 12 and an insulating membrane 13 as the outermost layer thereon. At the peripheral position of the front surface of the panel glass 10, a glass paste 14 including a silver powder is applied on the insulating membrane 13 of the outermost layer, and an electrode for earthing 15 formed by heating and baking is formed in the condition continued to the conductive membrane 12 at the lower layer. Consequently, the electric charge charged to the conductive membrane can be earthed securely without generating a dielectric breakdown to the insulating membrane of the outermost layer, and the electrode for earthing can be formed easily without hurting the multilayer membrane.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a panel for a cathode ray tube having a conductive film and a multilayer film having an insulating film formed thereon on the outer surface thereof, and a method for manufacturing the same.

[0002]

2. Description of the Related Art A cathode ray tube comprises a panel on which an image is projected, and a funnel and a neck forming the panel behind the panel.

During operation of the cathode ray tube, the electron beam emitted from the electron gun mounted in the neck tube is deflected by the deflection coil mounted around the funnel to scan the fluorescent screen on the back surface of the panel. There is a risk that other electronic devices around the cathode ray tube may malfunction or the human body may be adversely affected by leakage of unnecessary electromagnetic waves generated from the device or charging of the front surface of the panel.

Therefore, in the conventional cathode ray tube, a conductive film such as SnO ₂ having conductivity is formed on the outer surface of the panel in order to shield electromagnetic waves and prevent charging. However, since the surface of the conductive film is a mirror surface and has a higher refractive index than glass, if the film thickness is increased to increase conductivity, the surface reflection becomes large and the image is difficult to see. Therefore, it is not practical to use such a conductive film alone. Therefore, an antireflection property is provided by further forming an insulating film of SiO ₂ or the like having a low refractive index thereon.

Thus, in the conventional cathode ray tube,
A multilayer film is formed on the outer surface of a cathode ray tube panel in order to impart both conductivity and antireflection properties. In this case, the conductive film may be formed not only directly on the outer surface of the cathode ray tube panel but also through another film, that is, after the second layer. From the viewpoint of, it is necessary to form the outermost layer of the multilayer film.

[0006]

However, the electric charges charged in the conductive film are taken out to the external ground through, for example, the metal band for reinforcement wound around the skirt portion of the panel for the cathode ray tube, so that the insulating film is formed in the outermost layer. In the conventional cathode ray tube in which is formed, there is a problem that since the insulating film is interposed between the conductive film and the metal band, the resistance value is high, sufficient conduction cannot be achieved, and good grounding cannot be performed. In addition, conducting electric charges through the insulating film easily causes dielectric breakdown in the insulating film, which also causes damage to the film.
In order to solve this problem, when forming a multilayer film on the outer surface of the panel for a cathode ray tube, first, a conductive film is formed, and then,
After attaching the masking tape to a part of the conductive film to which the metal band is connected and forming the outermost insulating film,
A method has been proposed in which the exposed portion of the lower conductive film is formed in a part of the outermost insulating film by peeling off the masking tape, and conduction is provided from this exposed portion. However, this method requires two steps, that is, a step of attaching the masking tape and a step of peeling the masking tape, so that there is a problem of cost increase due to an increase in the number of steps in mass production.
In addition, in general, for attaching masking tape,
Although it is easy to automate with a manipulator, etc., the peeling work is not easy because the work nail of the manipulator easily scratches the film when the masking tape is peeled off, and as a result, the peeling work requires manual labor. There is a problem that work efficiency is extremely poor.

Therefore, an object of the present invention is to provide a panel for a cathode ray tube capable of surely grounding the electric charges charged in the conductive film in the multilayer film formed on the outer surface of the panel, and at the same time, a grounding electrode portion for grounding. Is to provide a method of manufacturing a panel for a cathode ray tube, which can be easily formed without damaging the multilayer film.

[0008]

The present invention has been made in view of the above problems and objects, and a multilayer film having a conductive film and an insulating film as the outermost layer on the conductive film is formed on the outer surface. A panel for a cathode ray tube, comprising a grounding electrode portion formed by coating a glass paste containing a metal powder on the insulating film and heating and baking the glass paste.

Further, according to the present invention, a multilayer film having a conductive film and an insulating film as an outermost layer is formed on the conductive film on the outer surface of the panel, and then a metal powder is deposited on the outermost insulating film. In a method for manufacturing a cathode ray tube panel, which comprises applying a glass paste containing and heating and baking the glass paste to form a grounding electrode part by permeating the insulating film of the outermost layer to reach a conductive film. is there.

[0010]

In the present invention, the glass paste is a paste prepared by mixing metal powder and frit glass and adding a solvent such as an organic binder to the mixture.

As the metal powder contained in the glass paste, silver, gold, aluminum, copper or the like can be used, but silver is preferable from the viewpoint of conductivity and cost.

The frit glass used for the glass paste includes PbO-B ₂ O ₃ system and PbO-ZnO-B ₂
Low melting point frit glass such as O ₃ system and PbO-B ₂ O ₃ -SiO ₂ system can be used. Especially, for a cathode ray tube panel, in a subsequent cathode ray tube assembling step, for example, sealing with a funnel or inside a bulb is performed. It is preferable to use a crystalline low-melting point frit glass that does not soften and flow even when these are reheated because they are heated during exhaust.

The metal powder contained in the glass paste is
The higher the content, the lower the resistance value and the higher conductivity can be obtained, but on the other hand, due to the small amount of frit glass, the permeation reaction rate of the glass paste into the insulating film during heating and firing is slow. It is considered to be. Therefore, it is more practical and preferable that the content of the metal powder in the glass paste is 5 to 15% by weight from both aspects of conductivity and productivity.

The material of the multilayer film formed on the outer surface of the panel is not particularly limited, but the conductive film is cheaper than In ₂ O ₃ and stable in performance as a transparent conductive film. The SnO ₂ film is preferably used.

Further, the outermost insulating film is preferably a SiO ₂ film having a low refractive index and having a good compatibility with glass paste.

In the present invention, a glass paste containing a metal powder is applied onto the outermost insulating film and heated and baked, so that the glass paste permeates into the outermost insulating film to reach the conductive film. As a result, a ground electrode portion that is electrically connected to the lower conductive film is formed.

The earthing electrode portion has excellent heat resistance because it is formed by heating and baking a glass paste containing a metal powder, and as a result, the metal powder undergoes flow deformation during oxidation or reheating. Stable characteristics as an electrode can be obtained without causing the above.

[0018]

EXAMPLES The present invention will be described below based on examples.

FIG. 1 is a vertical cross-sectional view of a cathode ray tube panel of the present invention, and FIG. 2 is an explanatory view of a method of manufacturing the cathode ray tube panel of the present invention.

On the outer surface of the panel glass 10, a multi-layer film 11 for imparting conductivity and antireflection property is formed. The multilayer film 11 has a conductive film 12 and an insulating film 13 as an outermost layer on the conductive film 12. Specifically, a SnO ₂ thin film having a film thickness of 270Å is formed as the conductive film 12 on the first layer, and a SiO ₂ thin film having a film thickness of 1100Å is formed on the second layer as a fine film as the third layer. SiO ₂ thin films having irregularities are formed as the insulating film 13, respectively.

In the peripheral portion of the front surface of the panel glass 10, a grounding electrode portion 15 formed by applying a glass paste 14 containing silver powder on the outermost insulating film 13 and heating and baking it is a lower conductive film. 12 is formed in a conductive state.

A method for manufacturing such a cathode ray tube panel will be described.

First, the panel glass 10 is washed and then preheated, and a mixed vapor of dimethyl tin dichloride and antimony trichloride (Sb / Sn) is sprayed on the outer surface of the panel glass 10 to obtain CV under normal pressure.
An SnO ₂ thin film doped with Sb is formed by the D method. Then, while rotating the panel glass 10 in a preheated state, a SiO ₂ -containing alcohol solution is dropped on the panel glass 10 and then naturally dried and baked to form a SiO ₂ thin film. Further, a SiO ₂ -containing ethanol solution is sprayed onto the panel glass 10 by a spray coating method to form a SiO ₂ thin film having fine irregularities. In this way, after forming the multilayer film 11 having the conductive film 12 and the insulating film 13 as the outermost layer on the conductive film 12 on the outer surface of the panel glass 10,
A glass paste 14 containing silver powder is applied on the outermost insulating film 13. Glass paste 14 is silver powder 1
0 wt% and PbO—B ₂ O ₃ -based crystalline low melting point frit glass (PbO 74.9%, B ₂ O ₃ 8.6%, ZnO
12.6%, SiO ₂ 2.0%, BaO 1.9%) 81
% And mixed with 1% of an organic binder to form a paste, and this glass paste 14 is formed by a manipulator, for example, at a predetermined position on the outermost insulating film 13 as shown in FIG. 2 (a). Apply to. Next, after the panel glass 10 is naturally dried, it is heated and baked at 450 ° C. for 30 minutes. As a result of this heating and firing, as shown in FIG. 2B, the glass paste 14 containing silver powder reaches the lower conductive film 12 while permeating the outermost insulating film 13 by the action of frit glass. In this way, the glass paste 14 becomes electrically conductive with the conductive film 12, and the ground electrode portion 15 is formed.

Using such a cathode ray tube panel, the reinforcing metal band wound around the skirt portion of the cathode ray tube panel and the earthing electrode portion 15 are brought into contact with each other to extract the electric charge of the conductive film 12 to the external earth. When the cathode ray tube was manufactured, the resistance value between the conductive film 12 and the metal band during the operation of the cathode ray tube was as low as 10 ⁵ Ω, and the outermost insulating film 13 did not cause dielectric breakdown.
I was able to make a good ground.

Further, since the grounding electrode portion 15 is formed by heating and firing the glass paste 14 containing the metal powder, it has excellent heat resistance, and the metal powder can be fluidized when it is oxidized or reheated. Stable characteristics as an electrode can be obtained without causing deformation or the like.

The conductive film in the multi-layer film is not limited to the case of being formed in the first layer, and can be similarly applied to the case of forming the second layer and subsequent layers through another film.

[0027]

As described above, according to the present invention,
It is possible to reliably ground the electric charges charged in the conductive film without causing insulation breakdown in the outermost insulating film, and to damage the multilayer film formed on the outer surface of the panel, to the grounding electrode part for grounding. It has an excellent effect that it can be easily formed without any need.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a cathode ray tube panel of the present invention.

FIG. 2 is an explanatory view of a method for manufacturing a panel for a cathode ray tube of the present invention.

[Explanation of symbols]

 10 Glass Panel 11 Multilayer Film 12 Conductive Film 13 Insulating Film 14 Glass Paste 15 Earth Electrode Part

Claims (2)

[Claims] 1. A multilayer film having a conductive film and an insulating film as an outermost layer on the conductive film is provided on an outer surface, and a glass paste containing a metal powder is applied onto the insulating film and heated and baked. A panel for a cathode ray tube having a grounding electrode portion formed as described above. 2. A glass paste containing a metal powder after forming a multilayer film having a conductive film and an insulating film as an outermost layer on the conductive film on the outer surface of a panel. Is applied and heated and baked, and the glass paste is permeated into the insulating film of the outermost layer to reach the conductive film to form a ground electrode part, thereby forming a panel for a cathode ray tube.