JPH0447648A - Shadow mask and its manufacture - Google Patents

Abstract

PURPOSE:To easily obtain precise and uniform electron beam passing holes by providing crystal orientation different in the rolling direction and the rectangular direction against the rolling direction and carrying out etching in the way of making the longitudinal direction of the electron beam passing holes become practically the rolling direction and carrying out press-molding into a shadow mask. CONSTITUTION:An ingot of an inver alloy is hot-rolled at 900 deg.C to give a 2-3mm thick plate. In this case, the crystal orientation is made different in the rolling direction and the rectangular direction against the rolling direction. The shadow mask raw plate in prior stage of the successive etching process has anisotropic crystal orientation. In the next etching process, both sides of the shadow mask raw plate are covered with a masking material for etching, and a prescribed etching solution is sprayed to form 200,000-300,000 slender electron beam passing holes arranged, for example, at 0.45-0.75mm intervals in a 20 inchtube. At that time, the masking material is so put as to make the slender electron beam passing holes have the same longitudinal direction of the slender electron beam passing holes as the rolling direction practically.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a shadow mask used in a color television picture tube and a method for manufacturing the same.

(Prior art) Shadow masks used in color television picture tubes are
It has the ability to project an accurate electron beam spot onto a three-color phosphor screen. Therefore, the relative position, diameter, and shape of the electron beam passage hole have a direct effect on image quality, and high processing accuracy of the electron beam passage hole is required. Furthermore, in order to prevent the generation of scattered electrons, a special process is required in which the surface of the electron beam passage hole facing the fluorescent screen is chamfered into a hemispherical shape. If these processing precisions are low, image quality will deteriorate due to doming.

Conventionally, such shadow masks have been processed by forming elongated electron passing holes by etching on the original plate of the shadow mask.

On the other hand, in recent years, the general demand for "fineness" of television screens has increased, and the development of communication systems, such as high-definition television systems, is progressing. Therefore, even in picture tubes, from the viewpoint of improving resolution, it is required to form even finer electron beam passage holes in the shadow mask. In addition, due to the thermal expansion of the high-definition shadow mask, the problem of positional deviation of the electron beam passage hole has arisen, and to solve this problem, Fe
The use of Ni-based amber alloy is being considered.

When opening an electron beam passage hole in an amber alloy, photoetching is usually performed, but the etching rate of the amber alloy is strongly anisotropic, and the etching rate of the +100+ crystal plane is fast, but the etching rate of the [1001 plane is slow.

Patent No. 1379343 and Patent J, 3392 B 9
In the issue, it is described that the crystal orientation of the shadow mask original plate before etching is aligned to the (1001 plane). By the way, the shape of the electron beam passing hole in the shadow mask is either round or elongated, but When doing so, it was difficult to make the short axis dimension of the elongated mold uniform with high precision.

According to the above-mentioned patent No. 1379343.133269, if the crystal planes are aligned to +1001 or a high degree, it is possible to obtain an elongated electron beam passing hole with a uniform short axis.
As the degree of inclusion of crystal planes other than the +1001 plane increases, the short axis of the elongated electron beam varies. The degree of this is 0.
In the electron beam passage hole of 600 μm x minor axis 0.155 pm, the major axis is ±0. (1003 μm 1 short axis and ±0.003 μm.) These slight variations affect the brightness and darkness of the image.

In addition, U.S. Pat. No. 4,846,747 discloses that an elongated electron beam passing hole formed by etching is used to prevent deformation during press forming by cold working for forming a shadow mask. A technique is described in which the longitudinal direction of the passage hole is perpendicular to the rolling direction.

This is done in a direction perpendicular to the rolling direction of the amber alloy in order to prevent deformation of the elongated electron beam passage hole that was previously provided during press forming by cold working as a shadow mask, which is generally performed. This study focused on the difference in yield strength of the two types.

(Problems to be Solved by the Invention) According to the present invention, the etching process for forming the electron beam passage hole can be easily controlled, fine and uniform electron beam passage holes can be easily obtained, and An object of the present invention is to provide a shadow mask that can efficiently obtain a shadow mask and a method for manufacturing the same.

[Structure of the Invention] (Means and Effects for Solving the Problems) The present invention cold-works a shadow mask material made of an amber alloy by roll rolling, and produces crystal orientations that differ in the rolling direction and the direction perpendicular to the rolling direction. etching so that the longitudinal direction of the elongated electron beam passage hole is substantially in the rolling direction; and after cutting the shadow mask material in which the electron beam passage hole is formed into a predetermined shape. , a method for producing a shadow mask comprising a step of press-molding into a shadow mask shape by warm pressing, and a shadow mask material made of an umber alloy having different crystal orientations in the rolling direction and at right angles to the rolling direction, This is a shadow mask in which the longitudinal direction of the electron beam passage hole and the rolling direction are substantially the same.

That is, the present invention was made by focusing on the fact that when an amber alloy is rolled, the crystal orientation is different between the rolling direction and the orthogonal direction.

First, this anisotropy of crystal orientation will be explained.

Figures 1 and 2 show the rolling rate of cold working by adjustment rolling just before etching in the shadow mask process diagram in Figure 3.
%, the (002) pole figure of the amber alloy is 40%. RD is the rolling direction, the direction perpendicular to the RD in the plane of the paper is the direction perpendicular to the rolling direction, and the direction perpendicular to the plane of the paper is the direction perpendicular to the plate. The isohard lines in the figure represent the degree of aggregation, and as the cold rolling rate increases, the degree of aggregation of (1001) on the original plate surface decreases.(The degree of aggregation of Nool is X-ray (002) (It is expressed by diffraction intensity.) By the way, in both Figures 1 and 2, the degree of aggregation of I +, 001 planes is smaller in the rolling direction, and in the direction perpendicular to the rolling direction, < +1
All 001 sides are available. For example, in Figure 1 for 20% rolling, the [1001 surface concentration in the direction tilted 15 degrees from the sheet surface in the rolling direction is the +1.001 surface concentration in the direction perpendicular to the rolling direction and tilted 30 degrees from the sheet surface. is the same as In the case of 40% rolled material (Figure 2), the (1001 concentration) in the direction tilted 10 degrees from the rolling direction from the sheet surface is the (1001 concentration) in the direction perpendicular to the rolling direction and tilted 15 degrees from the sheet surface. The same.In other words, the direction perpendicular to the rolling direction is 10
01 Finished items are available. As mentioned above, the crystal plane with a high etching rate is the [1001 plane, and when forming an electron beam hole by etching, it is aligned with the flool plane, so the precision of the hole is improved, so the long side of the elongated electron beam passing hole is It has been found that by making the direction substantially coincide with the rolling direction, the short axis can be obtained uniformly and accurately.

In addition, in the present invention, roll rolling is performed as described above.

After the etching process, the shadow mask shape is formed by warm pressing, so that the elongated electron beam passage holes are not deformed by the warm pressing. As a result, in the present invention, the electron beam passage hole can be formed with high precision in the etching process without considering the deformation of the electron beam passage hole in the subsequent process.

Next, a method for manufacturing a shadow mask according to the present invention will be explained with reference to FIG.

First, 900 ingots of amber alloy used in the present invention were prepared.
Hot rolled (]) at a temperature of 2-3 m
A plate of m thickness is obtained.

First, 900 ingots of amber alloy used in the present invention were prepared.
Hot rolled (1) at a temperature above °C, 2-3 m+
Obtained as a plate of n thickness.

The amber alloy used in the present invention has a weight of 34-
42% Ni, 0.8% or less Mn, 0.8% or less Cr0.
5% or less Si, 0.02% or less C, 0.02% or less S,
The remainder may be Fe or the like. 70%~ of this board
Cold working was performed by roll rolling (2) at a rolling rate of 95% to obtain a shadow mask original plate having a thickness of 0.1 to 0.3 mm.

Next, annealing at 650° to 1200°C as necessary (3)
and adjustment rolling (4). Note that the annealing (3) at this time is to align the crystal direction of the plate surface to the flool, and the adjustment rolling is to flatten the plate that has been bent due to high temperature annealing. is desirable.

The shadow mask original plate before the next etching step (5) has the anisotropy of crystal orientation shown in FIGS. 1 and 2.

In the next etching step (5), both sides of the shadow mask original plate are covered with an etching mask material, and a predetermined etching solution is sprayed to arrange the images in a 20-inch tube at a pitch of, for example, 0.45 to 0.75 mm. 200,000 to 300,000 elongated electron beam passing holes are formed. At this time, the etching mask material is arranged in the elongated electron beam passing hole so that the longitudinal direction of the electron beam passing hole is substantially the same as the rolling direction, as shown in FIG. Note that "substantially the same direction" refers to a deviation within a range that does not depart from the scope of the present invention, and "practical use" means that the deviation between the rolling direction and the longitudinal direction of the electron beam passage hole is approximately ±5°.

It is preferable that the cutout 6) of the shadow mask original plate be chamfered as shown in FIG.

Next, annealing is performed if necessary. In general, amber alloys have a large yield strength and resistance during press forming, and springback may occur even after press forming. Therefore, in order to reduce the yield strength, annealing is performed at 00°C to 1200°C in a vacuum, water, or an incurable gas.

Next, using a predetermined press die, it is warm-pressed (8) to form a mask shape. The warm pressing at this time is performed at a temperature of about 100 to 400°C.

The formed shadow mask is heat-treated in, for example, an atmosphere containing water vapor, and a blackened film of about 0.01 to 3 μm is formed on its surface (9).

The shadow mask manufactured as described above is assembled into a color television picture tube as shown in FIG. In other words, as shown in cross section in FIG. 5, the color picture tube 2 includes an electron gun 3 that emits an electron beam, a yoke 4 that changes the emitted electron beam, and a large number of long holes 6 for passing the electron beam. It includes a formed shadow mask 5 and a three-color fluorescent screen 7 that is irradiated with an electron beam. Shadow mask 5 is
It is arranged between the electron gun 3 and the fluorescent screen 7. electron gun 3
The three electron beams emitted from the shadow mask 5 are changed by the magnetic force of the yaw 4, their paths are controlled, and the electron beams are directed through the holes 6 of the shadow mask 5.
and reaches the three-color phosphor screen 7, and each beam passes through the phosphor screen 7.
It is designed to emit red, blue, and green phosphors.

(Example) A plate having a thickness of 2+on+ was obtained by hot rolling after melting a 36% Ni-Fe amber alloy. This was made into a thin plate with a thickness of 0.2+ om at a processing rate of 90% with cold rolling rolls, and annealed at 900°C. Further, it was made into a shadow mass plate by 5% adjustment rolling. This was photo-etched in the rolling direction to obtain an electron beam passing hole with a major axis of 0.6000±0.0003 μm and a minor axis of 0.155±0.0005 μm. Next, shadow masks were cut out at predetermined dimensions as shown in FIG. At this time, the surface of the shadow mask is good < +1
The crystal orientation is aligned to 001, and from the rolling direction (
The degree of aggregation of 1001 was strong. The shadow mask thick plate with these separated electron holes was subjected to hydrogen annealing at 950°C, warm pressed at 200°C, and molded into the shape of a shadow mask. Further, a blackening treatment was then performed in water vapor at 650° C. to complete a shadow mask.

In addition, as a comparative example, photoetching was carried out in the longitudinal direction of the electron beam holes in the direction perpendicular to the thick plate rolling direction in the above embodiment. As a result, the major axis is 0.8000±0.00
An electron beam passing hole with a diameter of 0.02 μm, a short axis of 0.02 μm, and a diameter of 1.55±0.003 μm was obtained. C-CRT is performed using these shadow masks. When the two were compared, the image of the C-CRT using the shadow mask of the present invention was clear and the brightness was 1.5 times that of the C-CRT using the shadow mask of the comparative example.

[Effects of the Invention] In the shadow mask according to the present invention, the precision of the electron beam passage holes is good and uniform, and a color picture tube with clear and bright images can be obtained.

[Brief explanation of drawings]

In Figures 1 and 2, the rolling ratio is 20%, 40%,
(002) shows the crystal texture of the shadow mask original plate of
Pole figure. FIG. 3 is a process diagram explaining the method of the present invention. FIG. 4 is a diagram showing an example of cutting out a shadow masking original plate in the method of the present invention. FIG. 5 is a sectional view of a color picture tube.

Claims (2)

[Claims] (1) A step in which a shadow mask material made of an amber alloy is cold worked by roll rolling to give different crystal orientations in the rolling direction and in a direction perpendicular to the rolling direction, and in the longitudinal direction of an elongated electron beam passage hole. a step of performing etching so that the shadow mask material is substantially in the rolling direction, and a step of cutting the shadow mask material in which the electron beam passage holes are formed into a predetermined shape and then press-molding it into the shape of the shadow mask by warm pressing. A method for manufacturing a shadow mask characterized by the following features. (2) In a shadow mask material made of an amba alloy that has different crystal orientation in the rolling direction and in the direction perpendicular to the rolling direction,
A shadow mask characterized in that the longitudinal direction of the elongated electron beam passage hole and the rolling direction are substantially the same.