JPH02192802A - Production of metallic sheet for shadow mask - Google Patents

Abstract

PURPOSE:To allow the vacuum adhesion of a reference pattern made of glass and to improve the quality of perforation by etching by executing rolling several times by using dull rolls subjected to fine ruggedness working and increasing the area occupying rate of the rugged surface on the front surface without increasing average roughness. CONSTITUTION:The surface of one roll or both rolls of work rolls for rolling are subjected to fine ruggedness working. The metallic sheet is rolled 3 to 5 times by using such dull rolls to form the surfaces consisting of the ruggedness having 0.2 to 1.mum Ra center line average height of the surface on the front surfaces of one or both surfaces of the sheet in such a manner that the area occupying rate of the surfaces satisfy >=80%. The air flow passages at the time of evacuation to a vacuum are sufficiently and uniformly assured and the adhesive property of the reference patterns made of glass is improved. The etching property of the metallic sheet for shadow masks is, therefore, improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of manufacturing a thin metal plate for a shadow mask.

(Conventional technology and disadvantages) In a shadow mask type color television CRT, a shadow mask having a large number of small holes perforated by photoetching is placed between the fluorescent screen and the electron gun for color selection. Ru. This material usually has a thickness of 0.1 to Q, 25
Fe-36Ni for mn+ mild steel plate or high grade applications
Alloy (Invar) is used.

The general manufacturing method of these shadow masks is as follows.

The metal thin plate material is cleaned, photoresist is applied, and after drying, a predetermined glass reference pattern is vacuum-adhered and exposed.
A large number of small holes are formed by etching with ferric chloride. Thereafter, it is formed into a spherical shape with a predetermined radius of curvature through the processing steps of annealing, leveling, and pressing, and is finally subjected to oxidation heat treatment and blackening treatment to improve heat radiation and prevent diffused reflection.

By the way, when a photoresist is applied to a thin metal plate with a smooth surface rolled by an ordinary work roll, and a glass reference pattern is layered on top of it and vacuum is drawn, the air flow resistance is large and the degree of vacuum is poor locally. Because of the formation of spots, there is a problem in that the adhesion with the glass reference pattern is poor and the quality of the etched product deteriorates. Therefore, a metal thin plate for a shadow mask is usually rolled using a roll called a dull roll whose surface has been subjected to fine irregularities by shot blasting, electric discharge machining, laser beam machining, or the like. Fine irregularities are transferred to the surface of the thin metal plate by dull roll rolling, and the adhesion between the air flow path and the blank glass reference pattern during vacuuming is improved to prevent the quality of perforated products from deteriorating during etching.

However, in the conventional rolling process in which the metal sheet is passed once using dull rolls, a large amount of the smooth surface obtained by rolling with a roll having a normal smooth surface remains on the surface of the thin metal sheet before rolling with the dull rolls. Area occupancy of the uneven surface transferred to the surface of the thin metal sheet by the uneven pattern on the surface of the dull roll (excluding the smooth surface area during rolling with this smooth roll).

The ratio of the uneven surface area transferred by the dull roll to the total surface area is defined as the uneven surface area occupation rate.)
Since the surface texture is small and the surface texture is not uniform, it cannot be said that a sufficient and uniform air flow path is secured during vacuuming. The quality of the products is still not satisfactory.

Accordingly, there is a need for a method of improving the quality of etched perforations in thin metal sheets for shadow masks.

(Knowledge related to problem solving) The present invention aims to improve the quality of perforated products by etching thin metal plates for shadow masks. By increasing the area occupation rate of the uneven surface formed on the surface of the thin metal sheet without increasing the center line average roughness Ra, a sufficient and uniform air flow path is ensured during evacuation. It was found that the adhesion of the reference pattern was improved and the etching properties were improved.

(Structure of the Invention) The above object is to form a thin metal sheet by applying fine irregularities to the surface of one or both rolls of a rolling work roll and rolling the metal sheet 3 to 5 times using the work roll. For a shadow mask, characterized in that the surface area occupancy rate of the surface consisting of irregularities with a surface centerline average roughness Ra of 0.2 to 1.0 μm formed on one or both sides satisfies 80% or more. This is achieved by a method for manufacturing thin metal sheets.

An increase in the surface centerline average roughness Ra formed on the surface of the thin metal sheet for a shadow mask by rolling means that the sloped surface of the unevenness on the surface of the thin metal sheet becomes longer. Therefore, although it is possible to secure an air flow path during evacuation, the space between the glass reference pattern and the surface of the thin metal plate becomes large, resulting in poor adhesion.

There is an appropriate range for Ra, and 0.2 to 1.0 μm is desirable.

As demonstrated by the examples below, the effect of the present invention appears when the number of rolling is three or more times, but if it exceeds five times, the strain imparted to the thin steel sheet increases and the etching property deteriorates. The uneven surface area occupancy was almost saturated after 5 rolling steps, and unnecessarily increasing the number of rolling steps would increase the manufacturing cost, so the upper limit was set at 5.

Ensuring a sufficient and uniform air flow path during vacuuming,
In order to improve the etching properties of the metal thin plate for shadow mask by improving the adhesion of the glass reference pattern, the area occupation rate of the uneven surface formed on the metal thin plate surface by rolling should be 80% or more, preferably 90% or more. % or more, and the surface center line average roughness Ra of the uneven surface
O, 2 to 1.0 μm.

(Specific disclosure of invention) Next, the present invention will be specifically explained with reference to Examples.

Material: C: o, ooa% (same below weight%), S
i: 0.14%, Mn: 0.30%, P: 0.00
An Fa-36Ni alloy consisting of 4%, s: o, ooio%, Ni: 36.14% and the balance Fe and inevitable impurities was used. After melting the Fe-36Ni alloy, it was made into a cold steel plate with a thickness of 0.160 mm by normal hot rolling and cold rolling processes. After annealing a cold-rolled steel plate with a thickness of 0.160 mm in a non-oxidizing atmosphere, the roughness pattern is transferred to both sides of the thin metal plate using a dull roll whose surface is finely roughened by shot blasting, usually from 1 to 5 times. The rolling process was performed by changing the Note that the center line average roughness Ra of the dull roll surface used for rolling is 0.90 to 1.0.
0 μm (the area occupation rate of the uneven pattern on the surface of the dull roll is 100%, and no smooth surface remains after roll grinding), and the reduction rate per pass of the dull rolling is 0.5 to 3. Rolling was performed within a range of 0%.

Next, after each of these thin metal plates having been rolled was washed, a photoresist was applied thereto, and after drying, a predetermined glass reference pattern was vacuum-adhered and exposed. After that, it was etched with ferric chloride and a hole opening test was performed.

Table 1 shows the surface center line average roughness Ra at each rolling number,
It shows the area occupation rate of the uneven surface on the surface of the metal thin plate and the defective hole opening rate after etching, where the defective hole rate refers to the percentage of the number of holes with defective shapes to the total number of holes formed by etching.

From Table 1, by rolling three or more times using dull rolls, the area occupation rate of the uneven surface can be increased without substantially increasing the center line average roughness Ra of one surface.

When the board is passed once or twice, the uneven surface area occupancy rate is 30.
% or less, but by passing the plate three times it becomes 80% or more, and by passing the plate four or more times it can increase to 90% or more.

As is clear from Table 1, by increasing the surface area occupancy of the uneven surface of the thin metal plate to 80% or more, the rate of defective holes can be reduced by 1.
By improving it to less than 0%, preferably to 90% or more, the open hole defect rate can be further reduced.

The above results can be better understood by referring to the attached photos. Attached Figures 1 to 6 are 100x micrographs showing the surface structures of non-dull rolled steel sheets and dull rolled sheets obtained in the Comparative Examples and Examples shown in Table 1. It can be seen that the effect is almost saturated after rolling five times.

Although the above examples are for Fe-36Ni alloy, the method of the present invention can be used not only for Fe-36Ni alloy but also for mild steel plates for shadow masks and other gold R thin plates used for photoetching purposes. be.

(Effects of the Invention) According to the present invention, it is possible to ensure a sufficient and uniform air flow path during evacuation during the manufacturing process of a metal thin plate for a shadow mask, so that the glass reference pattern can be completely vacuum-adhered. Can be done.

Therefore, the perforation quality in etching can be significantly improved, and the effect is significant.

[Brief explanation of the drawing]

Figures 1 to 6 are 100x micrographs showing the metal surface structures of non-dull rolled steel sheets and dull rolled steel sheets obtained in the comparative examples and examples shown in Table 1.

Claims (1)

[Claims] On the surface of one or both rolls of the rolling work roll,
By applying fine unevenness processing and rolling the metal thin plate 3 to 5 times using the work roll, the area occupation rate of the uneven surface formed on one or both sides of the metal thin plate is 80% or more, and the unevenness is The surface center line average roughness Ra of the part is 0
．． A method for manufacturing a thin metal plate for a shadow mask, which comprises configuring the thin metal plate for a shadow mask so as to satisfy the condition of 2 to 1.0 μm.