JPH0459731B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a shadow mask.

[Technical background of the invention and its problems]

Since the function of the shadow mask of the color picture tube is well known, the explanation thereof will be omitted.

The present inventors have already filed various applications for improving the quality of shadow masks and reducing manufacturing costs. For example, a shadow mask is coated with 0.5 to 3.0 μm of nickel plating in advance, and a blackening treatment is applied on top of it to reduce the chance of the blackening film falling off (Japanese Patent Application Laid-Open No.
No. 54-62773), and a method in which the flat mask is annealed and blackened at the same time, and replenishment blackening is performed after molding to reduce manufacturing costs (Japanese Unexamined Patent Publication No. 57-627).
57448), and furthermore, nickel plating of 0.5 to 3.0 μm is applied to the flat mask after photoetching.
The product is continuously coated, annealed and blackened to improve quality and reduce manufacturing costs.
Publication No. 93145).

At the time when these applications were filed, most of the materials used for shadow masks were rimmed steel, even if the carbon content varied, with the exception of special materials such as iron-nickel alloys. On the other hand, recently, killed steel, especially aluminum-killed steel, has been increasingly used as a material for shadow masks instead of rimmed steel.

By using aluminum-killed steel as the material for the shadow mask, it has become possible to dramatically improve the performance of the shadow mask over rimmed steel by reducing internal defects and improving forming. A new problem has arisen in which the adhesion strength of the blackening film is weak, and countermeasures are being taken by strictly controlling the blackening conditions and adding a certain amount of chromium to the material (Japanese Patent Application Laid-Open No. 81926/1983, (Japanese Patent Application Laid-open No. 1983-80246).

A method of simultaneously performing annealing and blackening that we have already applied for (Japanese Patent Application Laid-Open No. 57-57448, Japanese Patent Application Laid-open No. 58-57
93145), and if chromium-added materials are not used, manufacturing conditions must be strictly controlled.

[Purpose of the invention]

The present invention was made in view of the above-mentioned problems, and provides a shadow mask that makes it possible to obtain a shadow mask of good quality by devising manufacturing conditions without using special materials such as adding chromium. The purpose is to provide a manufacturing method for.

[Summary of the invention]

That is, the present invention heat-treats a flat mask formed from a shadow mask material by photoetching in a temperature range of 600 to 950°C in a mixed gas flow consisting of 10 to 50% H ₂ and the balance N ₂ with a dew point of 0 to 50°C. A method for manufacturing a shadow mask, which is characterized in that a thin blackened film is formed at the same time as annealing, and a predetermined blackened film is formed by blackening after press molding and degreasing, and a flat mask after photo-etching. After applying nickel plating of 0.5 to 3 μm, heat treatment is performed in a temperature range of 600 to 950 °C in a mixed gas flow of 10 to 50% H ₂ and the balance N ₂ with a dew point of 0 to 50 °C, and annealing is performed. At the same time, a method for manufacturing a shadow mask is characterized in that a thin blackened film is formed on the nickel plating, press molding and degreasing are performed, and both photo etching and heat treatment are performed in a continuous production line. .

[Embodiments of the invention]

Next, one embodiment of the present invention will be described. In this example, an experiment was conducted using a shadow mask made of aluminum-killed steel, which has poor adhesion to the blackened film.

First, an example of the chemical composition of aluminum-killed steel is C: 0.002%, Mn: 0.037%, S:
0.016%, P: 0.011%, Si: 0.02%, Al: 0.052
%, Fe: The remainder. However, unavoidable impurities are excluded.

Next, the state of the quality of the blackened film depending on the H ₂ concentration in N ₂ and the heat treatment temperature will be explained using figures. That is, in the first region 1, that is, below 600° C., annealing is insufficient. Further, in the second region 2, that is, above 960° C., the blackened film is so thick that it peels off when pressed. Further, in the third region 3, that is, the H ₂ concentration is less than 10%, the adhesion of the blackened film is poor.
Further, in the fourth region 4, that is, the H ₂ concentration is 50% or more, no blackening occurs. From this result, the range in which a blackened film with good adhesion to annealing can be obtained is in these first to fourth regions 1,
Region 5 surrounded by 2, 3, and 4 is good.
However, in the figure, a mixed gas with a dew point of 30°C was used.

In this region (5), atmospheric gas (H ₂ +
A similar blackened film can be obtained even if the dew point of N ₂ ) is changed from 0 to 50°C. However, if the dew point is less than 0℃, the blackening reaction and the decarburization reaction of the material will not proceed sufficiently, and if it exceeds 50℃, the decarburization reaction will be sufficient, but the blackening film will be thick and may peel off when pressed. Inconveniences arise in that water vapor condenses at the entrance and exit of the furnace and falls onto the shadow mask, causing rust.

As described above, according to this embodiment, it is possible to form a thin blackened film at the same time as annealing, regardless of the material of the shadow mask. Moreover, this thin blackened film is very dense and has good adhesion, and even if blackening is performed after press molding and degreasing, the adhesion of the blackened film will not deteriorate.

Further, this embodiment can also be applied to a case where a 0.5 to 3 μm nickel plating is applied to a flat mask after photoetching. In this case, it goes without saying that blackening after press molding is unnecessary due to the improvement in corrosion resistance due to nickel plating.

Further, in the present invention, the process of forming a flat mask by photoetching and the heat treatment may be performed separately, but energy saving and labor saving effects can be improved by performing the process in a continuous manufacturing run.

[Effects of the Invention] As described above, according to the method for manufacturing a shadow mask of the present invention, a thin blackened film can be formed during annealing even when aluminum-killed steel, which has poor adhesion to the blackened film, is used. Since it can prevent the peeling of the blackened film after press molding and degreasing, it ultimately contributes greatly to improving the withstand voltage characteristics of color picture tubes and reducing defects due to hole clogging, and its industrial value is great. .

[Brief explanation of the drawing]

The figure is an explanatory diagram showing the range in which a blackened film with good adhesion to annealing can be obtained in one embodiment of the present invention. 1...range where annealing is insufficient, 2...range where the blackened film is thick and peels off when pressed, 3...range where the adhesion of the blackened film is poor, 4...range where there is no blackening, 5...blackened with good adhesion to annealing Range where membranes can be obtained.

[Claims]

1. A processing solution consisting of a phosphor suspension and an electrolyte solution is flowed into the bulb to form a phosphor layer on the inner surface of the face, and after the processing solution is drained, the phosphor layer is freeze-vacuum dried. A fluorescent film forming method characterized by the following.