JP2002304944A - Method for manufacturing shadow mask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a shadow mask having little fluctuation in weight by suppressing the quantity of etching and efficiently and easily controlling its transmittance, when manufacturing the shadow mask complying with standards from a shadow mask having transmittance (hole diameter) out of standards, by controlling the transmittance (hole diameter) by a second etching. SOLUTION: A large hole is formed by applying the first etching by pasting a corrosion-resistant protective film 2 on the back of a metallic sheet 1. A corrosion-resistant overcoat is provided on its front surface, then the corrosion resistant protective film is peeled off, and the second etching controlling excess and deficiency of transmittance by adjusting a spraying pressure is applied to form a small hole on the back of the metallic sheet. Thereby a shadow mask is manufactured by providing a through hole.

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 shadow mask used for a color picture tube, and more particularly to a shadow mask capable of manufacturing an ultra-high-definition shadow mask used for a color monitor with less variation in transmittance. The present invention relates to a method for manufacturing a mask.

[0002]

2. Description of the Related Art The photoetching method is a processing method utilizing a corrosion phenomenon of metal, and is used for fine processing for manufacturing a shadow mask, an aperture grill, etc. provided in a color picture tube. An outline of a general photo-etching process for manufacturing a shadow mask or the like is as follows. A thin metal sheet material is coated with a photoresist film, and then an exposure master is overlaid and irradiated with ultraviolet rays. Here, a negative photoresist of a type that becomes insoluble by irradiation with ultraviolet rays is used as the photoresist. Next, this is treated with a developing solution to dissolve the photoresist in the portion not irradiated with the ultraviolet rays, thereby exposing the metal portion. Therefore, the metal sheet material in this state is treated with an etchant to dissolve the exposed metal portion to form a through hole, and thereafter, the remaining photoresist film is peeled off. This is a step of obtaining a mask product.

In such etching processing, steel (carbon steel, stainless steel, etc.) or iron-nickel alloy is frequently used as a material to be processed. Generally, a thin plate material of a shadow mask used for a color picture tube such as a television or a monitor has a thickness of 0.10 mm to 0.30 mm. In addition, the pitch of the pattern is particularly high in monitors used for personal computers and the like, since high-definition display is required.
A high-definition pattern of about 5 mm is used.

[0004] Ferric chloride solution is most widely used as an etching solution, and as an etching apparatus for industrial production, a ferric chloride solution is used while unwinding a rolled metal sheet. This is an etching apparatus that horizontally conveys to the etching tank that sprays and etches. In the case of a high-definition shadow mask having a hole diameter smaller than the plate thickness, a two-stage etching manufacturing method in which etching is performed in two stages is generally used.

[0005] This two-stage etching method is divided into a first etching step and a second etching step. In the first etching step, usually, first, from the side of the small hole,
Half-etching that does not form the through-hole is performed, washed sufficiently with water, and dried. Next, a resin having corrosion resistance is applied to the side surface of the half-etched small hole and cured, and a corrosion-resistant protective film is sufficiently adhered. As the corrosion-resistant resin, a resin such as an acrylic resin, an epoxy resin, a urethane resin, a polyethylene resin, or the like, or a resin such as a thermosetting resin or a thermosetting resin is used.

Next, in the second etching step, the side surface of the large hole is etched to form a half-etched portion on the side surface of the small hole and a through hole. The attached etchant is sufficiently washed with water and removed. Finally, the photoresist film and the corrosion-resistant protective film formed on the surface of the thin metal plate are immersed or sprayed in an alkaline stripping tank to dissolve the film. Further, it is a method of sufficiently washing with water and drying to obtain a shadow mask having a desired through-hole.

The quality of the shadow mask, which is a part of the color picture tube, is required to have a small variation in transmittance (the ratio of the area of the through hole to the area of the thin metal plate). It is also a problem that the transmittance varies within the plane of one shadow mask, but it is also a major problem that the transmittance varies between products. Recently, in personal computers, a GUI represented by Windows (registered trademark) has been used.
(Graphical User Interfac
e) is adopted, and there is a lot of software that spreads many windows on a monitor. Therefore, even if you make a small window to expand more windows,
In order not to break the characters displayed on the monitor,
A higher definition monitor is required. Therefore, in order not to vary the brightness on the monitor surface with high definition,
The standard of the transmittance of the shadow mask has become stricter, and a stricter standard has been required for the transmittance between products.

As described above, in the conventional two-step etching method, the side surface of the small hole is etched first, the small hole is provided with a corrosion-resistant protective film to protect the small hole, and then the side surface of the large hole is etched. The through-hole is formed by etching, and finally a shadow mask is obtained through a film removing step of removing the corrosion-resistant resin, photoresist and the like. The pass / fail judgment is made by measuring the transmittance of the shadow mask that has become a product.If the transmittance deviates from the standard due to some fluctuation in manufacturing conditions, for example, if the transmittance is high, the spray pressure is increased. If the transmittance is low, adjust the spray pressure.

In the conventional two-stage etching method, the spray pressure is adjusted by controlling the transmittance by adjusting the spray pressure for etching the side surface of the large hole in the second etching step. This is adjusted in the second etching step to avoid wasting the long strip-shaped metal sheet that has passed through the first etching step of etching the side surface of the small hole and the step of forming the corrosion-resistant resin. It is going.

For example, FIG. 3A is an explanatory view showing a cross-sectional shape of an example of a shadow mask in an initial stage of manufacturing when a shadow mask is manufactured by a conventional two-stage etching method. FIG. 3A shows a shadow mask whose transmittance is out of the standard and whose transmittance is lower than the standard. Further, FIG.
(A) A shadow mask whose transmittance is lower than the standard in the initial stage of manufacturing, which is manufactured by adjusting the spray pressure of the etching on the side surface of the large hole to increase the transmittance and keep the transmittance within the standard. It is explanatory drawing which shows the cross-sectional shape of.

As shown in FIG. 3A and Table 1, in this example, the shadow mask in the initial stage of manufacturing has a hole diameter (D1-a) of 54.9 μm and a small hole diameter of (D2-a).
a) 55.8 μm, large pore diameter (D3-a) 194.4 μ
m, and a transmittance (Ta) of 22.5%. By adjusting the spray pressure for etching the side surface of the large hole with respect to the shadow mask in the initial stage of the production, the shadow mask having the non-standard transmittance (Ta) of 22.5% is changed to the standard transmittance (Tb) 22. A shadow mask having a transmittance of 0.8% is manufactured by controlling the transmittance. The shadow mask having a transmittance within the standard is shown in FIG.
And as shown in Table 1, the pore size (D1-b) was 55.7 μm.
m, small pore diameter (D2-b) 55.8 μm, large pore diameter (D3-b)
b) It has 198.5 μm and a transmittance (Tb) of 22.8%.

[0012]

[Table 1]

Transmittance (Ta) 22.5% (pore diameter (D1-
a) 54.9 μm) to 22.8% transmittance (Tb)
(Pore diameter (D1-b) 55.7 μm) by controlling the side of the large hole by etching, this control can be understood by comparing with the large hole shape (C-1) in the initial stage shown by the dotted line. This is achieved by performing a large amount of etching from (C-1). In other words, when controlling the transmittance (hole diameter), controlling by etching the side surface of the large hole means that the etching amount is large. In other words, the control amount with respect to the etching amount is small, and the etching efficiency is poor. Become.

In the method of controlling the transmittance by correcting the etching amount on the side surface of the large hole, the volume of the shadow mask is greatly changed by the etching, so that the weight of the shadow mask tends to vary. The variation in the weight causes a difference in the mechanical strength of the shadow mask, and the shadow mask is deformed during the transportation of the product incorporated in the color picture tube, so that a problem that a product having a reduced display quality is mixed easily occurs. In particular, under the current situation where the thickness of the material is thin and the pitch of the pattern is becoming small, the occurrence of such a problem has become remarkable.

[0015]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a method for manufacturing a shadow mask in which a large number of through holes are formed in a long thin metal sheet by two-stage etching. When manufacturing a shadow mask having an out-of-specification transmittance (hole diameter) in an initial stage as a shadow mask having an in-standard transmittance (hole diameter) by controlling the transmittance (hole diameter) by adjusting the spray pressure of the second etching. In addition, there is provided a shadow mask manufacturing method capable of manufacturing a shadow mask in which the amount of etching of the second etching is not increased, the transmittance (hole diameter) can be efficiently and easily controlled, and the weight variation of the shadow mask is reduced. The task is to provide.

[0016]

SUMMARY OF THE INVENTION The present invention relates to a method of manufacturing a shadow mask in which a plurality of through holes are formed in a long strip-shaped metal sheet by using a photo-etching method. 1) A resist pattern for a large hole is formed on the surface of the metal sheet. A resist pattern for small holes is formed on the back surface, and 2) a first etching is performed by attaching a corrosion-resistant protective film on the back surface of the thin metal plate on which the resist pattern for small holes is formed, and a large surface is formed on the surface of the thin metal plate. Forming a hole; 3) providing a corrosion-resistant protective film on the surface of the metal sheet on which the large hole is formed; peeling off the corrosion-resistant protective film; and 4) determining whether the transmittance of the shadow mask is excessive or insufficient by adjusting the spray pressure. The second etching controlled by the adjustment is performed to form small holes on the back surface of the thin metal plate, and a large number of through holes are provided in the thin metal plate. 5) The corrosion-resistant protective film and the resist pattern for the large holes Removed a small hole resist pattern, a method of manufacturing a shadow mask, characterized in that to produce a small variation of the transmittance Shiyadoumasuku.

[0017]

Embodiments of the present invention will be described below in detail. FIGS. 1A and 1B are explanatory views showing a portion of an embodiment of a shadow mask manufactured by a method for manufacturing a shadow mask according to the present invention.

FIG. 1A shows a shadow mask produced by the method for producing a shadow mask according to the present invention.
It is explanatory drawing which shows the cross-sectional shape of a shadow mask in the initial stage of manufacture. FIG. 1A shows a shadow mask whose transmittance is out of the standard and whose transmittance is lower than the standard. FIG. 1B shows a shadow mask whose transmittance is lower than the standard in the initial stage of the manufacturing shown in FIG. 1A by adjusting the spray pressure for etching the side surface of the small hole to reduce the transmittance. It is explanatory drawing which shows the cross-sectional shape of the shadow mask which raised the transmittance within the specification.

As shown in FIG. 1A and Table 2, the shadow mask in the initial stage of the production in this example has, for example, a hole diameter (D1-A) of 54.9 μm and a small hole diameter (D2-A).
A) 55.8 μm, large pore diameter (D3-A) 194.4 μ
m, and a transmittance (TA) of 22.5%. By adjusting the spray pressure for etching the side surface of the small hole with respect to the shadow mask in the initial stage of this manufacturing, the shadow mask having a non-standard transmittance (TA) of 22.5% is changed to a standard transmittance (TB) 22. A shadow mask having a transmittance of 0.8% is manufactured by controlling the transmittance. The shadow mask having the transmittance within the standard is shown in FIG.
And as shown in Table 2, the pore size (D1-B) was 55.7 μm.
m, small pore diameter (D2-B) 56.5 μm, large pore diameter (D3-B)
B) 194.4 μm and a transmittance (TB) of 22.8%.

[0020]

[Table 2]

The transmittance (TA) is 22.5% (pore size (D1-
A) From 54.9 μm), the transmittance (TB) is 22.8%.
(Pore diameter (D1-B) 55.7 μm) by controlling the etching of the side surface of the small hole, the corrosion-resistant protective film is previously formed on the large hole shape (C-1) at the initial stage before the second etching. Since it is provided, it is not etched by the second etching from the side surface of the small hole, and this control is achieved by etching the small hole diameter and the hole diameter. Since the portion having the hole diameter is close to the side surface of the small hole, it is almost perpendicular from the side surface of the small hole to the hole diameter, and the small hole diameter and the hole diameter are almost the same. That is, the etching adjustment amount of the small hole diameter becomes the adjustment amount of the hole diameter, and the transmittance is controlled.

That is, when controlling the transmittance (hole diameter) by controlling the second etching from the side surface of the small hole, the amount of etching can be reduced. In other words, the transmittance (hole diameter) with respect to the etching amount can be reduced. The control amount is large, and the etching efficiency is high. At the same time, since the change in volume due to etching is small, the variation in the weight of the shadow mask is small.

In the method for manufacturing a shadow mask according to the present invention, since the transmittance is controlled by adjusting the spray pressure of the etching in the second etching step, the first etching step for etching the side surface of the large hole is performed. This is a manufacturing method that avoids wasting long strip-shaped metal sheets that have passed through the step of forming a corrosion-resistant resin. When a thin metal sheet material having a thickness of 0.08 mm or less is used, or an ultra-high-definition shadow mask in which the pitch of adjacent circles, ellipses, long and short rectangles, or mat-like patterns is 0.20 mm or less, is used. In the case of manufacturing, the method for manufacturing a shadow mask according to the present invention is effective. In order to improve productivity, the in-speed has been increased in the shadow mask production process, but the transmittance can be controlled efficiently even in production with increased line speed, so the amount of defective products during the control operation is small. It is.

FIG. 2 is a process chart for explaining a method for manufacturing a shadow mask according to the present invention. Hereinafter, a method for manufacturing a shadow mask will be described with a specific example.

An etching resist containing casein as a main component is applied to both sides of a thin aluminum-killed steel sheet having a thickness of 0.05 mm to a thickness of 10 μm. Exposure and development are carried out using a pattern mask formed in the shape of a blind having a pitch of 0.125 mm to obtain an aluminum killed steel sheet (1) on which a resist pattern is formed. Next, after heating at 220 ° C. for 5 minutes, a low-adhesive-thickness 0.02 mm-thick polypropylene-based protective film mainly composed of polypropylene is formed on the side of the small hole that is not etched in the first etching step (FIG. 2A). The organic synthetic film (corrosion-resistant protective film (2)) is attached.

In the first etching step, the specific gravity is 1.50.
Using a ferric chloride solution at 0 and 60 ° C. as an etchant, half etching is performed by spray etching from both sides of the thin plate at a predetermined spray pressure to form a desired large hole shape on the side surface of the large hole. Here, if even a small amount of the etchant remains on the half-etched surface, corrosion proceeds non-uniformly, which may cause variations in transmittance. Therefore, the etchant is completely washed and dried to completely remove the etchant. . (Figure 2
(B), (c))

Next, an ultraviolet-curable acrylic resin is applied to the side surfaces of the large holes in which the large holes were formed in the first etching step so as to prevent air bubbles from entering (FIG. 2D), and cured by irradiation with ultraviolet rays. Then, a corrosion-resistant protective film having a thickness of about 20 μm is formed. Further, the corrosion-resistant protective film (2) attached to the side surface of the small hole is peeled off (FIG. 2E). next,
In the second etching step (FIG. 2F), the specific gravity is 1.52.
Using a ferric chloride solution at 0 and 65 ° C. as an etchant, etching is performed from both sides by a predetermined spray pressure, and a through-hole having a desired transmittance (pore diameter) is formed by etching from the side surface of the small hole. Here, the substrate is sufficiently washed with water so as not to promote uneven corrosion, and the etchant is completely removed (FIG. 2G).

Finally, a 20% aqueous solution of caustic soda at 60 ° C. is sprayed to dissolve and remove the corrosion-resistant protective film and the etching resist formed on the side surfaces of the large holes and the small holes.
Drying (Fig. 2 (c), (g), (c)) Here, the transmittance of the shadow mask is measured for the first time, and if the transmittance is higher than the target transmittance, the spray pressure in the second etching step is used. Lower. Conversely, when the transmittance is lower than the desired transmittance, the operation of increasing the spray pressure is performed to obtain a shadow mask having a desired transmittance (pore diameter).

As described above, by etching the side surface of the small hole in the second etching step, the transmittance can be easily controlled in the second etching step even if the standard of the transmittance is strict. Defects can be reduced and the yield can be improved.

Further, a conventional manufacturing method, that is,
In the method of etching the side surface of the small hole in the first etching step, the adjustment of the spray pressure in the second etching step was not successful, and the spray pressure in the first etching step was sometimes adjusted. If the spray pressure is adjusted up to the first etching step, even the first etching step and the step of forming the corrosion-resistant protective film will be parts that do not conform to the transmittance standard and will produce a lot of defects. become.
According to the present invention, even if the standard of the transmittance is narrowed, the process of adjusting the spray pressure can efficiently control the transmittance (pore diameter) only by the second etching process. There is no need to adjust the spray pressure, thus improving the yield.

[0031]

According to the present invention, in the manufacture of a shadow mask in which a large number of through holes are formed in a long strip-shaped metal thin plate by using a photoetching method, the corrosion resistance is formed on the back surface of the metal thin plate on which the small hole resist pattern is formed. A first hole is formed by bonding a protective film and performing a first etching to form a large hole on the surface of the thin metal plate, and providing a corrosion-resistant protective film on the surface of the thin metal plate having the large hole formed thereon; Peel off,
Manufacturing method of a shadow mask for manufacturing a shadow mask by forming a small hole on the back surface of a thin metal plate by performing a second etching in which the transmittance of the shadow mask is controlled by adjusting the spray pressure to adjust the excess or deficiency of the transmittance of the shadow mask. Therefore, the amount of etching in the second etching does not increase, the transmittance (hole diameter) can be efficiently and easily controlled, and the manufacturing of a shadow mask capable of manufacturing a shadow mask with reduced weight variation of the shadow mask is performed. Method.

[Brief description of the drawings]

FIG. 1A is an explanatory diagram showing a cross-sectional shape of a shadow mask in an initial stage of manufacturing by a shadow mask manufacturing method according to the present invention. (B) is an explanatory view showing the cross-sectional shape of the shadow mask in which the transmittance of the shadow mask in the initial stage of the manufacturing shown in (A) is within the standard.

FIG. 2 is a process diagram illustrating a method for manufacturing a shadow mask according to the present invention.

FIG. 3A is an explanatory diagram showing a cross-sectional shape of a shadow mask in an initial stage of manufacturing by a conventional two-stage etching method. FIG. 2B is an explanatory diagram showing a cross-sectional shape of the shadow mask in which the transmittance of the shadow mask in the initial stage of the manufacturing shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Aluminum-killed steel thin plate 2 ... Corrosion-resistant protective film C1 ... Large hole shape at the initial stage D1-A, D1-B ... Diameter in the present invention D2-A, D2-B ... in the present invention Small pore diameters D3-A, D3-B, large pore diameters TA, TB in the present invention D-a, D1-b in the present invention D1-a, D1-b in the conventional method D2-a, D2-b in the conventional method ... Small hole diameters D3-a and D3-b in the conventional method. Large hole diameters Ta and Tb in the conventional method.... Transmittance in the conventional method a. First etching step i. …… Drying process d …… Corrosion resistant resin coating process e …… Corrosion resistant resin hardening process f …… Second etching process C …… Resin stripping process

Claims (1)

[Claims] 1. A method for manufacturing a shadow mask in which a plurality of through-holes are formed in a long strip-shaped metal thin plate using a photo-etching method. 1) A resist pattern for large holes on the surface of the thin metal plate and a resist pattern for small holes on the back surface. 2) forming a large hole on the surface of the thin metal plate by performing a first etching by attaching a corrosion-resistant protective film on the back surface of the thin metal plate on which the resist pattern for small holes is formed; A corrosion-resistant protective film is provided on the surface of the metal sheet on which the holes are formed, and the corrosion-resistant protective film is peeled off. 4) Second etching in which the transmittance of the shadow mask is controlled by adjusting the spray pressure is performed. Then, a small hole is formed on the back surface of the thin metal plate, and a large number of through holes are provided in the thin metal plate. 5) The corrosion-resistant protective film, the resist pattern for the large hole, and the resist pattern for the small hole are formed. Removed by It, the manufacturing method of the shadow mask, characterized in that to produce a small variation of the transmittance Shiyadoumasuku.