KR100567708B1 - Color discrimination mask for color picture tube - Google Patents

Abstract

Nickel iron alloy steel sheet made of nickel iron alloy containing 34 to 38% by weight of nickel, having a grain size number of 10 or more, a cross-sectional particle diameter of 50 mu m or less in a direction perpendicular to the rolling direction, and an average grain diameter of 30 mu m in the stretching direction. It is a color discriminating mask in which a hole is formed by etching a pattern on a substrate described below, which prevents deterioration of display characteristics due to deterioration of the opening shape, and is a color discriminating mask capable of high strength and fine pitch.

Description

COLOR DISCRIMINATION MASK FOR COLOR PICTURE TUBE}

BRIEF DESCRIPTION OF THE DRAWINGS The figure explaining the cross section of the opening part of a mask for color identification;

2 is a view for explaining a method for measuring the maximum particle size.

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a color identification mask for color tube, which can be used in any type of CRT, such as a shadow mask method and an aperture grill method for a color TV or a computer.

In the color tube for color display devices of color TVs and computers, a mask for color selection is used so that an electron beam is irradiated to a predetermined phosphor. A shadow mask made of a metal plate provided with a large number of small pores or an aperture grill provided with a plurality of slits is used as the color selection mask. The color display device of a computer requires a CRT tube with a small pitch capable of displaying a high resolution image.

When the color CRT is continuously used for a long time, the shadow mask or aperture grille is heated, because the accelerated electrons collide, it is distorted by thermal expansion, and the position of the electron beam on the fluorescent surface gradually shifts, causing color distortion in the image. .

Therefore, it is proposed to use a nickel iron alloy such as invar having a small expansion coefficient in place of a low carbon steel sheet or the like as a color discriminating mask to prevent color distortion due to thermal expansion.

However, alloys, such as Invar, had a problem that etching of a minute hole is difficult compared with a carbon steel plate.

In addition, as shown in Fig. 1, the color identification mask is etched from both sides, and the incident side 2 of the electron beam of the color identification mask 1 and the display surface side of the color identification mask are shown. In (3), small openings 4 and large openings 5 are formed, respectively. And the hole diameter through which an electron beam permeate | transmits at the intersection part 6 of an introduction hole and a normal hole is determined.

In etching, etching not only in the depth direction but also in the transverse direction proceeds at the same time, and when the etching is deepened, the transverse diameter also becomes large, so that large holes having a large aperture are formed.

If the hole having a larger aperture is formed than necessary, a large amount of metal is removed from the substrate, which causes a problem that the strength of the color discriminating mask is lowered.

In particular, due to the enlargement of color CRT display screens, color identification masks have also been enlarged, and production of display devices for TVs and computers has been carried out on a global scale, so that the CRT or its constituent members are transported over a long distance on the global scale. In long-distance transportation of large CRTs, there is a high possibility of being subjected to a large impact due to vibration or dropping during transportation, and a response to vibrations that may be received during transportation is required.

If the CRT is subjected to a large impact, the full-length color-identifying member supported by the frame such as aperture grille is stretched up and down, so it is unlikely that the CRT will be deformed by vibration of the member. In the case of the color-identifying member press-processed into the curved shape of, a part of the central curved surface may cause irreversible deformation when subjected to a large impact. In addition, such damage caused by CRTs is more likely to occur in large CRTs with large display screens, and more often occurs in CRTs having a larger curvature radius on CRT surfaces or CRTs having a flat surface.

In addition, when the diameter of the large hole increases, there is a possibility that connection with adjacent holes may occur. Therefore, it is difficult to reduce the pitch of the open space, and thus to obtain a color discriminating mask having a small pitch of the open space required for fine display. It was difficult.

On the other hand, it is known that the smaller the grain size of the material, the smoother the apertured wall surface after etching and the unnecessary radiation of electron beams to pass through are not generated. However, when the grain size is made small, there is a problem that the speed of etching decreases and the etching takes a long time as compared with the base material of the mild steel. In addition, only a small crystal grain size has a problem in that the shape of the hole to be formed does not become a round shape and a color discriminating mask having excellent characteristics cannot be obtained.

In addition, although a shadow mask using a nickel iron alloy in which trace components, surface cleanliness, or crystallographic orientation of a material are adjusted in a specific direction is known, one having sufficient characteristics could not be obtained.

The present invention provides a color discriminating mask made of a low-expansion nickel iron alloy, which prevents deterioration of display characteristics due to deterioration of the opening shape, decreases the strength due to the increase in the aperture size, and the connection to adjacent holes. The object of this invention is to eliminate the obstacle of fine pitch formation.

The present invention is a nickel-iron alloy steel sheet made of a nickel iron alloy containing 34 to 38% by weight of nickel in a color brown tube color discrimination mask, having a grain size number of 10 or more, and having a cross-sectional particle diameter in the direction perpendicular to the rolling direction of 50. It is a mask for color identification in which the pattern was provided in the base material which is below micrometer and the average particle diameter of 30 micrometers or less of extension direction, and the opening part was formed by etching.

According to the present invention, in the mask for color discrimination, by using a nickel iron alloy having a fine grain size and having a particle diameter of 50 μm or less in a cross section perpendicular to the rolling direction of the material, the coefficient of thermal expansion is small and the shape of the opening is excellent. It is possible to obtain a color discriminating mask capable of displaying a highly accurate display having a small diameter of the display surface side large diameter and a small opening pitch.

In other words, the metal removed by etching is not uniformly removed but is removed in accordance with grain boundaries. For this reason, it has been found that even in a metallic material having a small grain size, if large grains are present, when the large grains are removed by etching, the surface shape deteriorates along the large grain boundaries.

In the color-identifying mask of the present invention, the grain size number measured by the particle size measuring method specified in ASTM E112 (JIS G0551) is preferably 10 or more, and more preferably 11 or more. The smaller the grain size, the worse the round shape of the opening.

In addition, the size of the crystal grains is preferably 50 µm or less, and when grains larger than 50 µm are present, even if the grain size number is 10 or more, the surface shape of the pores deteriorates and roundness deteriorates.

Moreover, it is preferable that the average particle size of a extending | stretching direction is 30 micrometers or less. If the grain size is anisotropic, etching proceeds preferentially in the uniaxial direction. Since the material for shadow masks is produced by rolling, crystal grains are elongated in a direction perpendicular to the plate thickness, and etching proceeds preferentially in the stretching direction. As a result, there arises a problem that the etching proceeds in the direction perpendicular to the plate thickness in comparison with the plate thickness direction, and the enlargement of the large pore side occurs.

The roundness is described above in the case where the opening is circular, but when the opening is slit or slotted, the linearity of the opening formed by etching can be improved and the size of the opening formed on the display surface side can be improved. Since it can be made small, the high-definition display color discriminating mask which has arrange | positioned a minute opening at a small pitch can be obtained.

Hereinafter, the present invention will be described as examples.

Example 1

Water-soluble casein resist was applied to a nickel-iron alloy plate containing 36% by weight of 0.12mm nickel with a grain size number 11 measured by the particle size measurement method specified in ASTM E112 (JIS G0551), and then dried. The predetermined resist pattern was formed using the glass dry plate which patterned the pattern in the resist of this.

Subsequently, the surface is formed by exposure, a film treatment, and a baking process, and then the pores are formed on both surfaces of the patterned resist by using a ferric chloride solution having a liquid temperature of 60 ° C. and a specific gravity of 48 ° Beh (Baume degree for heavy liquid) as an etching solution. It sprayed from and performed etching. After the predetermined small pores are formed, acid-resistant resins such as paraffin and ultraviolet curable resin are filled and coated on the small pores, and then etched together from the surface forming the large-diameter pores, and then the small pores and the large pores ( After passing through the hole of a large opening, resin and resist were stripped with alkaline aqueous solution, and the shadow mask which has a circular opening part was obtained.

The characteristic of the obtained shadow mask was evaluated by the following evaluation methods, and the result was shown in Table 1.

Example 2

The nickel iron alloy was etched as in Example 1 except that a nickel iron alloy having a grain size of 10 and a different maximum grain size and an average grain diameter in the elongation direction was used. Table 1 shows.

Comparative Example 1

The nickel iron alloy was etched in the same manner as in Example 1 except for using a nickel iron alloy having a grain size of 9.5 and having a different maximum grain size and an average grain diameter in the elongation direction. Table 1 shows.

Comparative Example 2

Nickel iron alloy was etched as in Example 1 except that nickel iron alloys having a grain size number of 10 and different maximum grain diameters and average grain diameters in the extension direction were used. Is shown in Table 1.

Grain size Particle size (㎛) Extension direction average particle diameter (㎛) stain Opening shape Roundness (%) Hole diameter (㎛) Pore diameter (㎛) Hole diameter (㎛) Example 1 11.0 37 21.8 Good Good 99.0 242.6 129.2 127.2 Example 2 10.0 42 20.5 Good Good 98.7 243.0 129.0 127.2 Comparative Example 1 9.5 52 42.1 Bad Outline 96.1 247.0 131.7 127.0 Comparative Example 2 10.0 52 30.9 Bad Contour bend 97.6 245.2 131.4 127.1

(Assessment Methods)

1. stain

Observed with the naked eye with light from the shadow mask side.

2. Opening shape

It observed with the scanning electron microscope.

3. Roundness

A hole diameter is measured at least five points at any point on the main line with respect to one opening of the shadow mask. The roundness was computed by Formula 1 using the maximum value and minimum value of the obtained measured value. The measurement was made about at least 5 or more openings, and the average value evaluated.

Equation 1

Roundness (%) = minimum value of hole diameter / maximum value of hole diameter × 100

4. Maximum particle diameter

In Figure 2 will be described a method of measuring the maximum particle diameter.

2 (A) shows a cross-sectional view of the sample cut into a cross section perpendicular to the rolling direction. The crystal grains 12 constituting the nickel iron alloy steel sheet 11 extend in the rolling direction 13 by rolling, and are pressed and crushed in the plate thickness direction 14.

Fig. 2B is a view for explaining a method for measuring each grain, and measuring opaque glass on which a circle 15 of a predetermined diameter is placed on the grain 12 to be measured.

An opaque glass with a diameter of 20, 30, 40, and 50 μm was placed on a grain size measurement sample and observed under a microscope of 200 to 500 times magnification. If there are two or more protruding regions, and if there are two or more regions, draw a straight line at any point on the grain boundary phase of each protruding region, and maximize the maximum length. It measured as a particle diameter. When there were no two or more places, the maximum particle size was measured in the same manner by changing into small circles in the order of 40 µm, 30 µm and 20 µm.

5. Average particle diameter in extension direction

The average particle diameter in the extension direction was obtained by the following equation.

Equation 2

Average particle diameter in the extension direction = d × N ₁ / N ₂

However, d: average particle size-measured grain size Assuming that the shape of the crystal grains measured by the particle size measurement method specified in ASTM E112 (JIS G0551) is square, the length of one side is regarded as the average particle diameter from the average root area of the average cross-sectional area. Calculate.

Ni: The number of crystal grains cut | disconnected by the line segment (plate thickness direction, ie, z-axis direction) of a predetermined length perpendicular | vertical to the extending direction of a crystal grain.

N ₂ : The number of crystal grains cut by a line segment having the same length as the line segment obtained by obtaining N ₁ parallel to the elongated direction of the grain (the rolling direction or the direction perpendicular to the rolling direction, ie, the x-axis and y-axis directions).

N ₁ and N ₂ measured at least 5 o'clock using the sample which measured the crystal grain size, and used the average value.

The color identification mask for color-brown tube of the present invention is a low-expansion nickel iron alloy plate, which uses a crystal grain number and a crystal grain diameter in a predetermined range, and forms a hole by etching to form a pattern. Since the linearity of the openings is improved, and the roundness is improved, the roundness is improved, and the dimensional accuracy of the large diameter on the display surface side can be improved. Therefore, the mask strength can be improved and a high-definition mask having a fine pitch can be obtained. have.

Claims (1)

A color identification mask for color brown tubes, wherein the nickel iron alloy steel sheet is made of a nickel iron alloy containing 34 to 38% by weight of nickel, and has a grain size number of 10 or more and a particle diameter of a cross section perpendicular to the rolling direction of 50 μm or less. And a hole is formed by etching by forming a pattern on a substrate having an average particle diameter of 30 µm or less in the extension direction.

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