JPH11307005A - Flat mask for shadow mask and thin plate for shadow mask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flat mask for a shadow mask without stripe unevenness, by lowering visibility of the stripe unevenness generated by etching. SOLUTION: In this flat mask for a shadow mask, surface-roughness of an electron beam permeating hole meets following formulae, Ra=0.2-1.0 μm, Rq=0.3-1.5 μm, 1.0<Rq/Ra<=2.0. Preferably, Rq/Ra=1.2-1.5 or Rq=0.3-1.0 μm, and desirably, the flat mask is made of a Fe-Ni alloy material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat mask used for manufacturing a shadow mask used for a CRT type television monitor or a computer display.

[0002]

2. Description of the Related Art Shadow masks used in display devices such as color televisions and personal computers are not limited to conventional ones made of aluminum-killed steel,
Due to the demand for excellent low thermal expansion characteristics accompanying the enlargement and high definition of the display device, recently, a Fe-36% Ni-based alloy,
So-called invar alloy, Fe-31% Ni-5% Co
Alloys, so-called super-invar alloys, are increasing.

[0003] These shadow masks are provided with a large number of fine holes through which electron beams pass, that is, electron beam transmission holes. In order to obtain a high-definition and accurate image, the perforation accuracy of the electron beam transmission holes is extremely high. Must be high. This electron beam transmission hole has, for example, a plate thickness of 0.025 mm to 0.25 mm and a width of 400 mm to 100 mm.
The 0 mm steel strip coil is perforated by performing an etching process, followed by a soft annealing step, a press forming step, and a blackening step to complete a shadow mask.

[0004] Recently, these shadow masks have a problem of uneven etching called "smear streaks" which is observed on a flat mask after etching for the manufacture thereof. Since the determination of the etching unevenness is difficult to mechanically determine except for the case where the size or shape of the etching hole is changed, the visual determination using only oblique light is employed. Therefore, even if there is no problem in the original function, if it is recognized as unevenness by visual judgment, it may be defective as an external problem.

As a method of solving the above-mentioned problem due to the occurrence of uneven streaks, for example, as means for reducing the uneven streaks, Ni or Mn components by soaking as disclosed in JP-A-61-223188 and Japanese Patent Application No. 2-182828 are disclosed. And a method for suppressing nonmetallic inclusions to a certain amount or less as disclosed in Japanese Patent Application No. 62-284040.

[0006]

The above-described method is effective for reducing uneven streaks generated in a flat mask. However, with the recent increase in size and definition of shadow masks,
Judgment of uneven streaks occurring in a flat mask is becoming more severe, and it is difficult to completely eliminate the uneven streaks by visual inspection with the above-described method in which minute segregation and minute inclusions unavoidable in manufacturing remain.

Accordingly, the present invention has been made in view of the above-mentioned matters,
An object of the present invention is to provide a flat mask for a shadow mask having no stripes by reducing the visibility of the stripes generated by etching.

[0008]

Means for Solving the Problems First, the present inventors have investigated in detail the relationship between the quality of uneven streaks visually determined and the roughness of an etched surface of a flat mask having uneven etching. As a result, it was recognized that even in a material having the same segregation ratio and nonmetallic inclusions, there was a difference in the quality of occurrence of streaks due to the roughness of the etched surface.

As a result of further research by the present inventor, the uneven streaks generated in the flat mask can be adjusted by precisely adjusting the roughness of the etched surface over a wide range.
The present inventors have found that the visibility of striped streaks due to material defects such as segregation and nonmetallic inclusions can be reduced, and have reached the present invention. That is, according to the present invention, the surface roughness of the etched surface of the electron beam transmission hole is Ra: 0.2 to 1.0 μm, Rq: 0.3 to
1.5 μm and the value by Rq / Ra is 1.
It is a flat mask having a value of more than 0 and not more than 2.0, preferably a flat mask having a value of Rq / Ra of 1.2 to 1.5 or Rq of 0.3 to 1.0 μm. In order to obtain the low thermal expansion characteristics required for the shadow mask, it is desirable that the material be an Fe-Ni alloy material, particularly an Fe-36% Ni alloy material.

[0010] In the present invention, the roughness of the etched surface is reduced by etching using ferric chloride.
a: 0.2 to 1.0 μm, Rq: 0.3 to 1.5 μm, and the value of Rq / Ra exceeds 1.0.
0 or less, and preferably, the value by Rq / Ra is:
1.2 to 1.5, or Rq is 0.3 to 1.0 μm
By applying the shadow mask thin plate, the effect can be easily and reliably achieved.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The most important feature of the present invention is that the surface roughness of an etching surface of an electron beam transmission hole formed in a flat mask is optimally adjusted in order to reduce the visibility of streak of a shadow mask. Further, the specific adjustment value is clarified.

The uneven streaks considered in the present invention are irregularities which are locally visible on the surface of the electron beam transmitting hole and which can be visually identified. These local irregularities are caused by component segregation and pits of nonmetallic inclusions. I do. Although these component segregation and non-metallic inclusions can be reduced but cannot be completely removed, they are still determined as local uneven streaks in a high-definition mask.

Therefore, the present inventor has conducted a study to propose means for solving the above-mentioned problems, and as a result, it has been found that the surface roughness of the electron beam transmitting hole of the flat mask is optimally adjusted. The inventors have found that this is an effective method for eliminating uneven streaks due to unevenness, and have reached the present invention. Specifically, the surface roughness of the etched surface of the electron beam transmission hole is,
In the case of a flat mask having a Ra of 0.2 μm or more and a Rq of 0.3 μm or more, a local unevenness which is a problem visually is not caused by the absorption, and a mask having a uniform surface without streaks is selected. is there. However, in the present invention, R
If a and Rq are too large, the straightness of the etching hole is deteriorated and a desired shape cannot be obtained. Therefore, the upper limits of Ra and Rq are 1.0 μm and Rq are 1.5 and 1.5, respectively.
μm, and preferably the upper limit of Rq is 1.0 μm.

Incidentally, Ra and Rq of the present invention are surface roughness values defined by the following formula 1, and the measurement range thereof is either one-way range or two-way range with respect to the surface to be measured. It is enough to obtain the effect of the present invention.

[0015]

(Equation 1)

Further, in this embodiment, SRa and SRq are used as surface roughness values, and are defined by the following equation (2).

[0017]

(Equation 2)

What is particularly important in achieving the present invention is the ratio of Ra to Rq.
a is adjusted to be more than 1.0 and not more than 2.0. For example, when selectively etching relatively large non-metallic inclusion pits and crystal grain boundaries compared to other parts of the material, the resulting unevenness and non-metallic inclusion pits on the surface of the electron beam transmission hole formed as a result May be particularly noticeable in localization. In other words, this is a case where the presence of extremely local unevenness, that is, a case where the difference between the values of Ra and Rq greatly increases, and even if Ra and Rq no longer satisfy the present invention,
The stripes are recognized.

Therefore, in the present invention, in order to obtain excellent image quality with all flat masks, R means
The upper limit of q / Ra is adjusted to 2.0 or less, preferably 1.5 or less. Further, the lower limit of Rq / Ra is a means sufficient for obtaining the effect of the roughness adjustment of the present invention,
A value exceeding 1.0 was set, and preferably 1.2 or more.

Regarding the roughness of the electron beam transmitting hole, for example, Japanese Patent Application Laid-Open Nos. 5-202490 and 6-41688 disclose a method for increasing the amount of light transmitted through a flat mask.
A method has been proposed in which the surface roughness of the interface of the beam transmission hole is reduced to 0.90 μm or less in Ra. However, this is an idea to make the surface roughness as smooth as possible from the viewpoint of improving the etching accuracy with respect to the increase in the amount of electron transmission, and the surface roughness is controlled from the viewpoint of eliminating image deterioration due to uneven streaks. He had not.

FIG. 1 shows the range of the surface roughness of the electron beam transmitting hole which can achieve the effect of the present invention. The region surrounded by the thick solid line and the broken line is the present invention (however, the boundary line shown by the broken line is not included), and the hatched region is a preferable range. The specific surface roughness values shown in FIG. 1 correspond to the present invention and comparative examples evaluated in the present example. And, as described above, in order to obtain the low thermal expansion characteristics required for the shadow mask, in addition to the roughness adjustment of the present invention,
It is desirable that the material be an Fe-Ni-based alloy, particularly an Fe-36% Ni-based alloy having excellent low thermal expansion characteristics.

The method for adjusting the etching surface roughness according to the present invention includes, for example, the concentration, temperature,
Any means such as a method for adjusting the spray pressure and time, a method for adjusting the crystal grain size and crystal orientation of the material, and a method based on a combination thereof may be used. Preferably, for example, a thin plate for a shadow mask in which the surface roughness value of the present invention is achieved by etching treatment using ferric chloride,
The effects of the present invention can be easily and reliably achieved.

The effect of the present invention can be achieved by satisfying the surface roughness of the beam transmitting hole of the present invention.
In other words, the surface roughness of the beam transmitting hole provided in the shadow mask member immediately before the blackening treatment step may satisfy the present invention, so to say, the shadow mask member press-formed through the etching step. , Its application is possible.

[0024]

EXAMPLES In order to obtain a flat mask according to the present invention and a comparative example, first, an Invar alloy thin plate for an Fe-36% Ni-based shadow mask was prepared. Then, in order to form an electron beam transmission hole in the thin plate, an etching process using ferric chloride was performed to obtain a flat mask.

The surface roughness of the electron beam transmitting holes of the flat mask was measured using a laser microscope. Since the measurement surface is a spherical surface, after fitting to fit the curved surface shape, the cutoff value is set to 1/1 / of the measurement length.
By removing the waviness component as 5, a curved surface with roughness was extracted, and SRa and SRq were determined from the curves. Then, a visual observation was made on the streak quality of the electron beam transmission hole surface, and those in which no streaks were observed were evaluated as ○, and those in which streaks were slightly observed but had no practical problem were evaluated as Δ,
Those which have uneven streaks and pose a problem in practical use are marked with x. Table 1 shows the results.

[0026]

[Table 1]

From Table 1, it can be seen that the flat mask Nos. Nos. 1 to 7 are Comparative Example Nos. In comparison with Nos. 8 and 9, no visual unevenness due to local unevenness was observed, and in particular, No. 9 satisfying the preferable Rq / Ra ratio and Rq value of the present invention.
In Nos. 1 to 4, it is possible to obtain excellent uneven streaks. In addition, in the present invention No. No. 7 satisfies the preferable Rq / Ra ratio and achieves characteristics that are practically satisfactory as a shadow mask. However, since the Rq value exceeds 1.0 μm, No. 7 does not. 1 to
4 is slightly inferior to 4.

On the other hand, if the comparative example is described, 8
Means that while satisfying the Ra and Rq values of the present invention, Rq / R
Since the a-ratio is large, local unevenness occurs, which is confirmed as uneven streaks. And No. In No. 9, the occurrence of local unevenness due to the low Ra and Rq values is confirmed as uneven streaks, and both have problems in use as shadow masks.

[0029]

According to the present invention, the segregation of components due to impurities in the material, which has been difficult to reduce, and the visibility of local uneven streaks caused by nonmetallic inclusions can be greatly reduced. The above yield can be greatly improved. further,
Since the frequency of applying special processes such as special refining to materials is reduced, it is also effective in terms of cost reduction, and its industrial effect is great.

[Brief description of the drawings]

FIG. 1 is a diagram showing a surface roughness range of an electron beam transmitting hole which can achieve the effects of the present invention.

Claims (5)

[Claims] The surface roughness of an electron beam transmitting hole is Ra:
A flat mask for a shadow mask, which satisfies 0.2 to 1.0 [mu] m and Rq: 0.3 to 1.5 [mu] m, and the value of Rq / Ra is more than 1.0 and not more than 2.0. 2. The value according to Rq / Ra is 1.2 to 1.5.
The flat mask for a shadow mask according to claim 1, wherein 3. The flat mask for a shadow mask according to claim 1, wherein Rq is 0.3 to 1.0 μm. 4. The flat mask for a shadow mask according to claim 1, wherein the flat mask is made of an Fe—Ni alloy material. 5. The method according to claim 1, wherein the surface roughness when etching is Ra:
A thin plate for a shadow mask, which satisfies 0.2 to 1.0 μm and Rq: 0.3 to 1.5 μm, and the value of Rq / Ra is more than 1.0 and not more than 2.0.