JPS59149638A - Manufacture of shadow mask - Google Patents

Abstract

PURPOSE:To form fine electron beam pass holes highly accurately with high density by arranging the crystallizing direction on the mask face of shadow mask original plate. CONSTITUTION:Shadow mask material composed of alloy having face-centered cubic lattice or body-centered cubic lattice structure such as invar type alloy is cold-rolled forcefully to collect (100) crystal faces on the rolled face. Then it is thermally processed to collect (100) crystal faces on the rolled face to obtain a shadow mask original plate. Thereafter (100) crystal face of shadow mask plate is etched to form electron beam pass holes 3a', 3b', etc. through the shadow mask original plate.

Description

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

[Technical background of the invention and its problems]

BACKGROUND ART A so-called shadow mask tube using a Nyado mask has been well known as a color television picture tube.

FIG. 1 is a perspective view showing the basic structure of a shadow mask tube using a delta type electron gun.

That is, as shown in FIG. 1, the shadow mask tube has a large number of electron beam passing holes 9a, 9h, . . . between the three electron guns 1a to IC and the three-color fluorescent surface 2. It is configured by providing a mask 3. This Nyadou mask 3 shapes the electron beams emitted from three electron guns 1a to IC, aiming at specific electron beam passing holes 1, for example, 3C, and forms the respective color fluorescent parts 2 to 2C of the three-color fluorescent surface 2. Each has the function of projecting an accurate beam spot.

The electron beam passing holes 3a, Jb, . . . are generally as shown in the enlarged cross-sectional view of FIG.

The surface 4 (hereinafter referred to as the "mask surface") facing the fluorescent surface is hollowed out into a semicircular shape.

Efforts have been made to prevent the generation of scattered electrons.

The relative positions, diameters, and shapes of the electron beam passage holes 3m, 3b, . . . in the shadow mask 31'' are set to have sufficiently high accuracy.

Incidentally, if the machining accuracy of the electron beam passage holes 3m, Ib, etc. is low, it becomes a factor that causes image quality deterioration such as color bleeding and color unevenness called doming phenomenon.

On the other hand, in recent years, general demand for "fine detail" on television screens has increased, and the transmission system is also shifting to a so-called high-definition television system that uses approximately twice the number of scanning lines as the current system. Therefore, in order to cope with this, there is a strong demand for the development of a picture tube that can further improve the performance and reproduce fine-grained images with clarity. In response to such demands, it has become necessary to form electron beam passing holes in a mask with high density and fineness.

However, with the conventional photoetching method generally used in the manufacture of shadow masks, it is extremely difficult to form fine and highly accurate electron beam passage holes. That is, even if an attempt is made to form a fine and highly accurate electron beam passing hole using the conventional technique, the electron beam passing hole obtained by this method will not be able to form the electron beam passing hole as seen from the mask surface 4, as shown in FIG. 3, for example. Passing hole, 9g, 3b,・
The hole position and shape of ... were non-uniform and the accuracy was low.

In addition to this problem, as the density and miniaturization of the electron beam passage hole increases, the ratio of the electron beam emitted from the electron gun colliding with the shadow mask increases, resulting in the increase in the temperature of the shadow mask. A new problem has arisen in that the thermal expansion of the Yadoku mask changes the relative positional relationship between the electron beam passage hole and the phosphor, resulting in a doming phenomenon.

[Purpose of the invention]

The present invention has been made to address such problems, and its purpose is to provide a method for manufacturing a mask that can form fine electron beam passage holes with high precision and high density. There is a particular thing.

[Summary of the invention]

The present invention has been made based on the fact that the non-uniformity of the shape of the electron beam passing holes described above is caused by the uneven crystal orientation on the mask surface of the conventional shadow mask original plate. It is.

In other words, as shown in FIG. 3 (aJ), if the directions of the crystal grains on the mask surface 4 of the shadow mask original plate and the face opposite thereto are uneven, this original plate (=crystal grains that are easily etched when etching is performed) There is a difference in etching speed between the crystal grains and the crystal grains that are difficult to be etched.As a result, the etching progress direction 6 is tilted and other variations occur, as shown in the same figure (bJ
As shown in the figure, the positions and shapes of the electron beam passing holes 3a, Jb, . . . are non-uniform.

The present inventors set the tioo>crystal plane at 35% on the mask surface.
It has been found that if a shadow mask original plate having a concentration of at least 40% or more is used, the etching accuracy can be greatly improved.

Here, the degree to which (100) crystal planes are gathered on the mask surface is defined as first order.

That is, it is the ratio of the component in the (100> direction of each polycrystalline grain in the axial direction perpendicular to the mask surface for all crystal grains, and is expressed by the linear equation.

Here, ■φ is the volume ratio of the grains, and φ is the angle between the direction perpendicular to the mask surface and the <i o o> direction of each crystal grain.

Therefore, in the present invention, a shadow mask material made of an alloy with a face-centered cubic lattice structure or a body-centered cubic lattice structure, such as an Invar alloy, is subjected to strong cold rolling to collect (110) crystal planes on the rolled surface. Afterwards, this hard-rolled shadow mask material is heat-treated at a temperature higher than the recrystallization temperature of the alloy to form (
100) Gather crystal planes to obtain a shadow mask original plate,
A feature of the present invention is that electron beam passing holes are formed in the shadow mask original plate by etching the (100) crystal plane of the shadow mask original plate.

In addition, one aspect of the present invention is to heat-treat the shadow mask material at a temperature higher than the recrystallization temperature of the alloy after hard rolling to form a rolled surface (io
o) A shadow mask material with aggregated crystal planes is further cold-rolled at a rolling rate of 25% or less, which is a range in which the crystal planes do not rotate, as necessary, to improve the accuracy of the plate thickness. In addition, this shadow mask original plate is subjected to an etching process.

〔Effect of the invention〕

Thus, according to the present invention, a shadow mask original plate having (100) crystal planes gathered on the rolled surface is obtained, and the electron beam passing holes are formed by etching the (100) crystal planes, so that a difference in etching speed occurs. Therefore, it becomes possible to form fine electron beam passing holes with high precision and high density. Therefore, it is possible to manufacture a shadow mask using a shadow mask tube that provides a fine-grained screen.

In addition, since we use an alloy with a face-centered cubic lattice structure or a body-centered cubic lattice structure, such as an imper-type alloy with a very low coefficient of thermal expansion, as the shadow mask material, the occurrence of doming phenomena caused by thermal expansion due to temperature rise of the shadow mask is also prevented. can. Therefore, by using the shadow mask manufactured according to the present invention, it is possible to obtain a V-yadu mask tube that meets the requirements for high-definition television systems. Moreover, the method of the present invention is easy to implement and has great practical advantages.

[Embodiments of the invention]

An embodiment of the present invention will be described below.

The shadow mask material used in the present invention is preferably an alloy with a face-centered cubic lattice structure or a body-centered cubic lattice structure because of the need to align crystal planes as described above. Moreover, thermal problems can be solved if the coefficient of thermal expansion is almost zero, so Impa alloy (36N i -F e )
, super constant steel (32N1-5Co-63Fe), stainless steel constant m'fl (54Co -9,3Cr, -36
, 5Fe), 43Pd 57Fe alloy, etc. are preferably used.

In this example, an ingot alloy of 36N]-Fe is melted, the ingot is made into a wire rod with a diameter of 6 through a continuous hot wire making process, and this wire rod is forged at right angles to the longitudinal direction, and the thickness A plate having a cross section of 2 mm and a width of 50 mm is used as a mask material.

This shadow mask material was roughly rolled through hot rolling at 900°C, which is the main thickness reduction process, until the thickness was 1.
A plate with a cross section of 100 m in diameter is obtained. In addition, the above 90
Since 0°C is a temperature higher than the recrystallization temperature of the above-mentioned Impa alloy, it is possible to gather (100) crystal planes on the rolled surface, but this is not particularly significant in the present invention. do not have.

Next, the plate obtained by this hot rolling is strongly worked at a rolling rate of 80% or more, for example 90% (=thus, the thickness is 0.1 m
, cold rolling is performed once or multiple times to obtain a plate with a width of 1000 mm. This strong working rotates the crystal plane, and by applying heat treatment for 1 hour at 920°C, which exceeds the (110) crystal plane, the crystal axis rotates, and the (110) crystal plane rotates again.
100) Surfaces gather. As mentioned above, the degree of aggregation is desirably 35% or more, more preferably 40% or more.

Incidentally, in experiments conducted by the present inventors, the surface condition of the rolled surface after each of the above steps was examined by X-ray diffraction, and it was found that the (100) crystal plane was %, with subsequent cold hard rolling (110)
The number of crystal faces was 38%, and 42% of the (100) crystal faces, which were stabilized by heat treatment at 920° C. exceeding the recrystallization temperature, were aggregated.

The shadow mask original plate obtained in this way.

For example, ferric chloride 43%, ferrous chloride 6%, hydrochloric acid 0.1
Using an etching solution consisting of an aqueous solution of The pitch of the beam passing holes is approximately 0.
．． 3 m, and approximately 520,000 electron beam passing holes were formed as a shadow mask for a 14-inch television, and a view of this as seen from four directions on the mask surface is shown in FIG. 4 (bJ).

On the other hand, in order to compare and contrast, after cold rolling by strong working described above, strain relief heat treatment was performed at 500°C, which is below the recrystallization temperature. When photoetching was performed using a shadow mask material, the shape of the electron beam passage hole was similar to that shown in FIG. 3 (bl).

As is clear from the above results, according to this example, finer 'electron beam passing holes can be formed with high precision and high density; This is because the direction is approximately perpendicular to the mask surface 4.

In this way, by gathering the (100) crystal planes on the mask surface, it is possible to obtain a shadow mask with high density and fine electron beam passing holes, but it is necessary to further improve the accuracy in the thickness direction of the shadow mask. If there is a problem, use a shadow mask original plate that has been cold rolled by strong working, then heat treated at a temperature higher than the recrystallization temperature, and then cold rolled the necessary number of times at a rolling reduction not exceeding 25%. Good. That is, if the rolling ratio is 25% or less, it is possible to suppress the rotation of the (100) crystal plane on the rolling surface.

According to the above method, it is possible to increase the pitch width by about % and the number of electron beam passing holes by about 5 times compared to conventional shadow masks, and also to make the shadow mask material have a very low coefficient of thermal expansion. By using Invar alloy, it is possible to prevent the doming phenomenon caused by thermal expansion of the shadow mask.
A shadow mask that meets the purpose of high-definition television can be obtained.

Note that in this embodiment, a method for manufacturing a shadow mask having a round electron beam passage hole was particularly explained.
In particular, the present invention is not limited to this, and can also be applied to, for example, a method for manufacturing a slit-type or stripe-type shadow mask.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a schematic configuration of a shadow mask tube using a delta type electron gun, Fig. 2 is a sectional view of the electron beam passage hole of the shadow mask shown in Fig. 1, and Fig. 3 (1) (b). 1 is a diagram for explaining a shadow mask formed by a conventional shadow mask original manufacturing method (2). FIG. 4 is a diagram for explaining a shadow mask formed by a manufacturing method according to an embodiment of the present invention, and FIG. 4 (Jl) shows a cross-sectional view of the shadow mask. Cross-sectional view showing the etching situation, the same figure (bl is the colored fluorescent surface of the same shadow mask surface viewed from the mask surface, 4... mask surface
C, C/...electron beam. Applicant's representative Patent attorney Takehiko Suzue Picture 1 a Picture 2 (b) Continued from page 1 0 Author: Masayuki Ito Tokyo Shibaura Electric Co., Ltd. Research Institute, 1 Komukai Toshiba-cho, Saiwai-ku, Kawasaki City

Claims (1)

[Claims] (1) A shadow mask material made of an alloy with a face-centered cubic lattice structure or a body-centered cubic lattice structure is heat-treated at a cold temperature to form a shadow in which crystal planes are gathered on the rolled surface. The process of obtaining a mask original plate and the above (
100) A method for manufacturing a shadow mask, comprising the step of etching a crystal plane to form an electron beam passage hole in the shadow mask original plate. (2) The method for manufacturing a shadow mask as set forth in claim (1), wherein the shadow mask material is an in-ground alloy. (3) Claim (1) characterized in that the cold hard working rolling is performed at a rolling ratio of 80% or more, and (100) crystal planes are gathered on the rolling surface.
1. Method for manufacturing a shadow mask as described in Section 1. (4) The method for manufacturing a shadow mask according to claim (1), wherein the mask material is a plate obtained by forging a shadow mask material and then hot rolling it. a step of work-rolling, and a step of heat-treating the strongly work-rolled shadow mask material at a temperature higher than the recrystallization temperature of the alloy to obtain a shadow mask material in which (100) crystal planes are gathered on the rolled surface; The shadow mask material in which the (100) crystal planes are assembled is cold-rolled at a rolling rate of 25% or less to obtain a shadow mask raw material, and the (100) crystal planes of this nyadou mask raw material are etched to form the shadow mask material. A method for manufacturing a shadow mask, characterized in that it comprises a mask original plate (- a step of forming an electron beam passage hole). The method for producing a shadow mask according to item 5). (7) The strong cold rolling is performed at a rolling rate of 80% or more, and (ioo) crystal planes are aggregated on the rolled surface. A method for manufacturing a shadow mask according to claim (5). (8) The shadow mask material is a plate obtained by forging and hot rolling a shadow mask material. A method for manufacturing a shadow mask as described in claim (5) characterized by: