JP2000348613A - Manufacture foe color cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simultaneously perform blackening treatment and stabilizing treatment under atmosphere by heating a shadow mask assembled by welding a molded mask body to a mask frame to heat the mask at a temperature in a specific range under atmosphere, blackening the mask body, and removing distortion stress of the shadow mask. SOLUTION: A flat mask is annealed under wet hydrogen atmosphere, and a press molded mask body is cleaned, then a separately molded and cleaned mask frame is welded to the mask body to assemble a shadow mask. An elastic support body is welded with the mask frame of the shadow mask, and locked to a stud pin provided on a panel to assemble a panel/mask assembly. The panel/mask assembly is heated to 440-500 deg.C under atmosphere, the shadow mask is blackened and simultaneously stabilized, black oxide films are formed on the surfaces of the mask body and the mask frame, and distortion stress remaining on the shadow mask is removed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a color cathode ray tube, and more particularly to a method for manufacturing a color cathode ray tube in which a shadow mask comprising a mask body and a mask frame is improved.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 4, a color cathode ray tube is provided on an inner surface of a panel 1 constituting an envelope.
A shadow mask 3 is arranged so as to face the phosphor screen 2 made of a color phosphor layer, and the shadow mask 3 emits light from an electron gun 6 provided in a neck 5 of a funnel 4 constituting an envelope together with the panel 1. The three electron beams 7B, 7G, and 7R to be selected are incident on the three-color phosphor layer to form a structure for displaying a color image.

In general, as shown in FIG. 5, the shadow mask 3 has a large number of electron beam passage holes 10 for selecting three electron beams incident on the three-color phosphor layer on a surface 9 facing the phosphor screen. Mask body 11 and mask frame 1 welded to the periphery of mask body 11
The elastic support 13 welded to the mask frame 12 is provided with a stud pin 14 provided on the panel 1.
(See FIG. 4) to support the inside of the panel 1.

At present, such a shadow mask 3 includes:
The mask body 11 and the mask frame 12 are both formed from a cold-rolled steel plate.
The mask frame 12 may be formed of a cold rolled steel plate formed of an Invar material made of an Fe-Ni alloy containing up to 40%.

Conventionally, the shadow mask 3 is manufactured by annealing a plate-like mask having a large number of electron beam passage holes formed by photoetching in a wet hydrogen atmosphere, for example, as shown in FIG. The mask thus formed is formed by press forming to form a mask body.
After the formed mask body is washed, it is heated in a mixed gas atmosphere at a temperature / time schedule 16 shown in FIG. 7 and is kept at about 600 ° C. for 10 minutes to perform a blackening treatment to form a black oxide film. . Next, the shadow mask is assembled by combining the blackened mask main body with a separately formed and cleaned mask frame and welding.

This shadow mask is then assembled with a panel by welding an elastic support to a mask frame, and assembling a panel / mask assembly.
Heat at the temperature / time schedule 17 shown in FIG.
The temperature is kept at 15 ° C. for 15 minutes, and a stabilizing process for removing the strain stress remaining on the shadow mask is performed. The stabilized shadow mask is thereafter used as an optical mask when a phosphor screen is formed on the inner surface of the panel by a photographic printing method.

[0007] The reason for the blackening treatment of the shadow mask as described above is to prevent the rust of the mask body and improve the heat radiation so that the temperature of the shadow mask is increased by the collision of the electron beam during the operation of the color cathode ray tube. This is to prevent it.

The reason why the stabilizing process is performed after the panel / mask assembly is assembled and before the phosphor screen is formed is that the phosphor screen is formed using the shadow mask as an optical mask without removing the strain stress remaining on the shadow mask. Then, by heating at the time of sealing (joining) between the panel and the funnel performed after the phosphor screen is formed,
The distortion stress remaining in the shadow mask is removed, the alignment relationship between the phosphor screen and the shadow mask is deviated, and the electron beam is not correctly incident on the three-color phosphor layer, causing color misregistration. In order to prevent the deviation of the matching relationship.

However, the assembly of the shadow mask described above,
In the processing, since the blackening processing and the stabilizing processing are performed separately, two large heat treatment furnaces are required, and there is a problem that equipment costs and maintenance costs are increased.

As a method for solving such a problem, Japanese Patent Application Laid-Open No. 2-100236 discloses a method in which a shadow mask is supported on a jig having dummy stud pins, and a blackening process and a stabilizing process are performed in a heat treatment furnace at about 600 ° C. At the same time. Also, Japanese Patent Publication No. 61-24780
Japanese Patent Application Laid-Open Publication No. H10-260, 1991, discloses a shadow mask made of a cold-rolled steel plate, in a range of 440 to 560 ° C. in an atmosphere of steam, combustion gas, CO ₂ gas, N ₂ gas containing residual oxygen, or a mixed gas thereof. It has been proposed to perform a stabilizing treatment at the same time as a blackening treatment in a heat treatment furnace.

[0011]

As described above, in the conventional method for manufacturing a shadow mask, a blackening process and a stabilizing process are required until the shadow mask is used as an optical mask when a phosphor screen is formed by a photographic printing method. Two large heat treatment furnaces that perform the treatment separately are required, and there is a problem that equipment costs and maintenance costs increase. As a method for solving such a problem, there has been proposed a method in which a shadow mask is supported on a jig with dummy stud pins and is processed in a heat treatment furnace at about 600 ° C. to simultaneously perform a blackening process and a stabilizing process. . According to this processing method, not only a shadow mask whose mask body is made of a cold-rolled steel plate but also a shadow mask made of an amber material forms a black oxide film in a short time, and at the same time, removes the strain stress remaining in the shadow mask. be able to. However, in this processing method, since the film formation rate of the black oxide film is high, it is necessary to use a reducing hybrid gas that slows down the oxidation rate in order to obtain stable processing.

As another method, black is treated in a heat treatment furnace at a temperature of 440 to 560 ° C. in an atmosphere of steam, combustion gas, CO ₂ gas, N ₂ gas containing residual oxygen, or a mixed gas atmosphere thereof. There has been proposed a method of performing a stabilizing process at the same time as a stabilizing process. However, this processing method is intended for a shadow mask whose mask body is made of a cold-rolled steel plate, and performs the processing in a specific gas atmosphere.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and does not require a shadow mask to be heated to a high temperature of 600 ° C. and does not use a mixed gas. The purpose is to perform at the same time.

[0014]

In a method of manufacturing a color cathode ray tube, a mask body formed into a predetermined shape is welded to a mask frame to assemble a shadow mask. The blackening treatment of the mask body by heating to ℃ and the stabilizing treatment for removing the strain stress of the shadow mask were performed simultaneously.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a color cathode ray tube is manufactured by using a cold rolled steel plate or an amber material as a mask material and forming a large number of electron beam passage holes by photo-etching to form a flat mask. Then, the flat mask is annealed in a wet hydrogen atmosphere, and the mask body is formed by press forming. After cleaning the formed mask body, a separately formed and cleaned mask frame is combined and welded to assemble a shadow mask. Next, an elastic support is welded to the mask frame of the shadow mask, and the elastic support is engaged with a stud pin provided on the panel to assemble a panel / mask assembly. Thereafter, the panel / mask assembly is heated to 440 ° C. to 500 ° C. in an air atmosphere to blacken and stabilize the shadow mask to form a black oxide film on the surface of the mask body and the mask frame. At the same time, the strain stress remaining in the shadow mask is removed.

FIG. 3 shows an example of a temperature / time schedule for simultaneously performing the above-described blackening process and stabilizing process.
In this example temperature / time schedule 20, the panel
The mask assembly is heated at a rate of about 12 ° C./min,
After cooling for about 40 minutes, the mixture is cooled at a rate of about 5 ° C./min, and the entire treatment is performed for 180 minutes.

Next, as shown in FIG. 2, using the panel / mask assembly subjected to the above-described blackening and stabilization, the inner surface of the panel is formed by a photographic printing method using the shadow mask as an optical mask. Form a phosphor screen. Next, the panel on which the phosphor screen is formed and a funnel with a conductive film formed on the inner surface and a frit glass coated on the sealing surface with the panel are combined and heated, and bonded (sealed) with the frit glass. Wear). Next, the electron gun is sealed in the funnel neck of the envelope including the joined panel and the funnel. Next, the sealed envelope of the electron gun is evacuated while being heated. After that, finishing processes such as getter flash for increasing the degree of vacuum in the envelope, aging for activating the cathode, and high voltage processing for increasing the withstand voltage are performed.

As described above, the mask body and the mask frame are welded to assemble a shadow mask, and an elastic support is attached to the shadow mask to assemble a panel / mask assembly. 500 ℃
When the mask is heated to about 600 ° C., the mask body is made of a cold rolled steel plate as well as a shadow mask made of amber material. Without using
The blackening process and the stabilizing process can be performed simultaneously in one heating furnace, so that the equipment cost and the heating and maintenance cost of the heating furnace can be significantly reduced.

That is, in general, the blackening treatment is most stable at about 600 ° C. and can be performed in a short time. However, at this temperature, the generation rate of the black oxide film is high.
It is necessary to reduce the generation rate of the black oxide film by using a reducing hybrid gas. On the other hand, the stabilization process calculates
When processing is performed at a relatively low temperature of about 0 ° C., by extending the processing time, the strain stress remaining on the shadow mask can be sufficiently removed. Further, by lengthening the processing time, it is possible to form a black oxide film not only on a mask body made of a cold-rolled steel plate but also on a mask body made of an amber material in which a black oxide film is hardly formed.

That is, even at a relatively low temperature of 440 ° C. to 500 ° C., by performing the treatment in the air for a long time, the stabilizing process and the blackening process can be performed simultaneously without using a specific gas.

[0022]

When the shadow mask is assembled and then heated to 440 ° C. to 500 ° C. in the air, the blackening process and the stabilizing process of the shadow mask can be performed simultaneously in one heating furnace, and the equipment cost and the heating furnace Can greatly reduce the operation and maintenance costs.

[Brief description of the drawings]

FIG. 1 is a view showing assembly and processing of a shadow mask in a method of manufacturing a color cathode ray tube according to an embodiment of the present invention.

FIG. 2 is a view showing steps after a phosphor screen is formed in a method of manufacturing a color cathode ray tube according to an embodiment of the present invention.

FIG. 3 is a diagram showing a temperature / time schedule when performing a blackening process and a stabilizing process in assembling and processing the shadow mask shown in FIG. 1;

FIG. 4 is a diagram showing a configuration of a color cathode ray tube.

5A is a plan view showing a configuration of a shadow mask, FIG. 5B is a sectional view taken along line XX of FIG. 5A, FIG.
FIG. 5C is a cross-sectional view taken along the line CC of FIG.

FIG. 6 is a diagram showing assembly and processing of a conventional shadow mask.

FIG. 7 is a diagram showing a temperature / time schedule of blackening processing in assembling and processing a conventional shadow mask.

FIG. 8 is a view showing a temperature / time schedule of a stabilizing process in assembling and processing a conventional shadow mask.

[Explanation of symbols]

20: Temperature / time schedule for blackening and stabilizing

Claims (1)

[Claims] 1. A mask body formed in a predetermined shape and a mask frame are welded to assemble a shadow mask.
A method of manufacturing a color cathode ray tube, wherein the shadow mask is heated to 440 ° C. to 500 ° C. in the air to simultaneously perform a blackening process of the mask body and a stabilizing process of removing a strain stress of the shadow mask.