JPH06103914A - Color cathode-ray tube - Google Patents

Abstract

PURPOSE:To prevent generation of a deterioration of the color purity. CONSTITUTION:The component of the tension of a shadow mask 6 in the shorter axis direction is shorter than the component in the longer axis direction. Since the curvature amount at the center of the longer arm side of a mask frame 5 when the shadow mask 6 is not operated in such a form is small, the slipping amount of an electron beam passing hole near the outer periphery on the shorter axis to the outer side is small, even though the shadow mask 6 is heated and expanded thermally, and the mask frame 5 is restored to the original condition of no bending.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a television receiver,
The present invention relates to a color cathode ray tube used for a display device of an information terminal device.

[0002]

9 is a schematic sectional view showing a color cathode ray tube, FIG. 10 is a view showing a mask frame used in the color cathode ray tube shown in FIG. 9, and FIG. 11 is a sectional view taken along line AA of FIG. 12 is a cutaway perspective view showing a part of the mask frame shown in FIG. As shown in the drawing, a color fluorescent surface 10 is provided on the inner surface of the panel 1, the funnel 2 is welded to the panel 1, and the electron gun 7 is attached to the neck portion 2a of the funnel 2.
, The deflection coil 9 is attached to the funnel 2, the mask frame 5 is attached to the panel 1, and the shadow mask 6 is attached to the mask frame 5. The shadow mask 6 has a large number of electron beam passage holes. It is provided. The shape of the electron beam passage hole is a circular shape, a slot shape, a slit-shaped pore, or the like. When the shape of the electron beam passage hole is circular, for example, the diameter is 0.08.
mm electron beam passage holes are provided at a pitch of 0.2 mm. Further, if the electron beam passage holes are arranged so that the lines connecting the centers of the electron beam passage holes intersect at an angle of 60 °, all the electron beam passage holes are arranged at the same intervals.

In this color cathode ray tube, the electron gun 7
The three electron beams emitted from are scanned on the shadow mask 6 by the deflection coil 9, the electron beam passes through the electron beam passage hole of the shadow mask 6, and the electron beam excites the color fluorescent surface 10 to form an image. To reproduce. In this case, in order to achieve good color reproduction, it is necessary to accurately land the electron beam that has passed through the electron beam passage hole of the shadow mask 6 on a predetermined fluorescent body of the color fluorescent surface 10.

However, the rate at which the electron beam passes through the shadow mask 6 is 15 to 20%, and most of the other electron beams collide with the shadow mask 6 and cause the shadow mask 6 to expand by heating. When the electron beam is increased to obtain a bright screen, the shadow mask 6
The expansion amount of is large. As a result, the landing position of the electron beam on the fluorescent body fluctuates greatly, resulting in deterioration of color purity.

Therefore, in the conventional color cathode ray tube, Japanese Patent Laid-Open Nos. 61-80735 and 61-80 are used.
As disclosed in Japanese Patent No. 736, the shadow mask 6 is attached to the mask frame 5 with a uniform tension applied to the shadow mask 6.

In this color cathode ray tube, even if an electron beam collides with the shadow mask 6 during operation and the shadow mask 6 is heated and thermally expanded, the shadow mask 6 does not sag due to thermal expansion. It is possible to prevent the deterioration of the color purity due to the slack of the shadow mask 6.

[0007]

However, in such a color cathode ray tube, since tension is applied to the shadow mask 6 when it is not operating, the central portion on the long side of the mask frame 5 is Although it is curved inward, when the shadow mask 6 is collided with an electron beam during operation and the shadow mask 6 is heated and thermally expanded, the mask frame 5 returns to its original non-curved state. The electron beam passage hole near the outer periphery on the short axis BB shown in 10 is shifted to the outside, and the landing position of the electron beam passing through the electron beam passage hole is shifted to the outside. The amount of deviation of the landing position is greatest in the portion near the outer circumference on the short axis BB. Therefore, deterioration of color purity occurs.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a color cathode ray tube which does not cause deterioration in color purity.

[0009]

In order to achieve this object, according to the present invention, in a color cathode ray tube in which the shadow mask is attached to a mask frame in a state where tension is applied to the shadow mask, the tension of the shadow mask is The component in the short axis direction of is made smaller than the component in the long axis direction.

[0010]

In this color cathode ray tube, the amount of bending of the central portion of the long side of the mask frame when not in operation is small, so that the electron beam collides with the shadow mask during operation and the shadow mask is heated. Even if the mask frame is in the original non-curved state due to thermal expansion due to thermal expansion, the amount of deviation of the electron beam passage hole to the outside in the portion near the outer periphery on the short axis is small.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a view showing a tension state of a shadow mask of a color cathode ray tube according to the present invention. As shown in the figure, since the component of the tension of the shadow mask 6 in the minor axis direction is smaller than the component in the major axis direction, the amount of bending of the central portion on the long side of the mask frame 5 when not operating is small, During operation, the shadow mask 6 is bombarded with an electron beam, and the shadow mask 6 is heated and thermally expanded.
Even if is not in the original curved state, the amount of deviation to the outside of the electron beam passage hole in the portion near the outer circumference on the short axis is small, so the landing position of the electron beam in the portion near the outer circumference on the short axis is small. Since the amount of deviation is small, deterioration of color purity does not occur. For example, the component of the tension of the shadow mask 6 in the major axis direction is 12 kg / mm ² , and the component in the minor axis direction is 6 kg.
When it was set to kg / mm ² , the dimension of the mask frame 5 in the minor axis direction was reduced by only 0.05 mm from the original dimension. As a result, the luminance during operation is 150 cd / m ²
The amount of deviation of the landing position of the electron beam in the portion close to the outer periphery on the short axis during the entire surface raster was 5 μm or less.
On the other hand, when the component of the tension of the shadow mask 6 in the major axis direction is 9 kg / mm ² and the component in the minor axis direction is 9 kg / mm ² as in the conventional case, the dimension of the mask frame 5 in the minor axis direction is set. Was reduced by 0.3 mm from the original size. As a result, the amount of deviation of the landing position of the electron beam in the portion near the outer periphery on the short axis at the time of full-color rastering with a luminance of 150 cd / m ² during operation was 35 μm.

Next, a method of manufacturing the color cathode ray tube according to the present invention will be described. First, a ferritic stainless steel plate having a thickness of 2.3 mm is press-molded to produce a mask frame 5 having a substantially uniform cross-sectional shape, and a 0.08 m diameter is formed on the entire surface of mild steel having a thickness of 0.025 mm.
m electron beam passage holes are provided at a pitch of 0.2 mm,
The shadow mask 6 is produced. Next, as shown in FIG. 2, the end portion of the shadow mask 6 is grasped by the chuck 13,
The shadow mask 6 has a force F _{1 in the} major axis direction and a force F _{2 in the} minor axis direction.
Then, the shadow mask 6 is fixed to the mask frame 5 by laser welding in a state where the tension component of the shadow mask 6 in the major axis direction is 12 kg / mm ² and the component in the minor axis direction is 6 kg / mm ² . Next, the peripheral portion of the shadow mask 6 is cut.

In the method of manufacturing the color cathode ray tube, the end portion of the shadow mask 6 is grasped by the chuck 13 and the shadow mask 6 is pulled in the major axis direction and the minor axis direction, but as shown in FIG. The shadow mask 6 may be fixed to the mask frame 5 while the shadow mask 6 is heated and expanded.

Next, another method of manufacturing the color cathode ray tube according to the present invention will be described. First, as shown in FIGS. 4 and 5, a ferritic stainless steel plate having a thickness of 2.3 mm is press-molded to produce a mask frame 15 having a long side of 400 mm. In this case, the long side is concave with a radius of curvature of 20000 mm. Next, as shown in FIG. 6, the mask frame 15 is provided with 8 kgF at the center of the short side.
Compressive force F ₃ was added, while substantially central portion of the compressive force F ₄ of 3kgF addition, the temperature was maintained at 30 ° C. of the long side, 14
The expanded shadow mask 6 heated to 0 ° C. is fixed to the mask frame 15 by laser welding. Next, the compressive forces F ₃ and F ₄ applied to the mask frame 15 are removed.

In the manufacturing method of this color cathode ray tube, the length of the long side is 400 mm and the radius of curvature is 20.
However, when the radius of curvature is less than 15 times the length of the long side, the shadow mask 6 to which tension is applied cannot form a continuous surface, and the radius of curvature is longer than the length of the long side. When it exceeds 150 times, the effect of suppressing the deformation of the mask frame 15 is insufficient. Therefore, the curvature radius may be set to 15 to 150 times the length of the long side, and the curvature radius may be set to 50 times the length of the long side. It is appropriate to double it.
Further, the compressive forces F ₃ and F ₄ may be appropriately selected depending on the strength of the mask frame 15 and the like, but when there is no great difference between the strength on the long side and the strength on the short side of the mask frame 15,
By making the compressive force F ₃ larger than the compressive force F _4, it is possible to reduce the reduction amount of the dimension of the mask frame 15 in the minor axis direction after the shadow mask 6 is fixed.

Next, another method of manufacturing the color cathode ray tube according to the present invention will be described. First, as shown in FIGS. 4 and 5, a ferritic stainless steel plate having a thickness of 2.3 mm is press-molded to produce a mask frame 15 having a long side of 400 mm. In this case, the long side is concave with a radius of curvature of 20000 mm. Next, as shown in FIG. 7, the mask frame 15 is provided with 8.4 k at the center of the short side.
While applying a compressive force F _{5 of} gF and maintaining the temperature at 30 ° C., the shadow mask 6 heated and expanded at 140 ° C. is welded along the welding line 14 a, that is, the central portion of the long side of 200 mm.
It is fixed to the mask frame 15 by laser welding leaving only this. Next, as shown in FIG.
After removing the compressive force F _{5 applied} to the mask frame 15, a compressive force F _{6 of} 5.6 kgF is applied to almost the center of the long side of the mask frame 15.
And the temperature is maintained at 30 ° C., the shadow mask 6 is moved along the welding line 14b, that is, the central portion 20 of the long side.
0 mm is fixed to the mask frame 15 by laser welding. Next, the compressive force F applied to the mask frame 15
Remove ₆ .

In this method of manufacturing a color cathode ray tube, laser welding is performed by leaving only the central portion of the long side of 200 mm, and then the remaining portion is laser-welded. However, only 1/4 or more of the length of the long side is obtained. Laser welding may be performed while leaving it. The compressive forces F ₅ and F ₆ are 8.4 kgF and 5.6 k, respectively.
Although gF is used, the compressive forces F ₅ and F ₆ may be appropriately selected according to the strength of the mask frame 15.

In the manufacturing method of the color cathode ray tube described above, the case where the compressive force on the mask frame 15 is applied to one point at the center of the short side and the long side has been described, but the present invention is not limited to this. The same effect can be obtained by compressing at two symmetrical positions or at more compression points.

In the manufacturing method of the color cathode ray tube described above, the shadow mask 6 is used as the mask frames 5 and 15.
However, the shadow mask 6 may be fixed to the mask frames 5 and 15 by resistance welding or the like.

[0020]

As described above, in the color cathode ray tube according to the present invention, the electron beam collides with the shadow mask during operation, the shadow mask is heated and thermally expanded, and the mask frame is curved to its original shape. Even if it does not occur, the amount of deviation of the electron beam landing position near the outer periphery on the minor axis to the outside is small, so the amount of deviation of the landing position of the electron beam is small, causing deterioration in color purity. There is no. As described above, the effect of the present invention is remarkable.

[Brief description of drawings]

FIG. 1 is a diagram showing a tension state of a shadow mask of a color cathode ray tube according to the present invention.

FIG. 2 is an explanatory view of a method of manufacturing a color cathode ray tube according to the present invention.

FIG. 3 is an explanatory view of another manufacturing method of the color cathode ray tube according to the present invention.

FIG. 4 is an explanatory view of another method of manufacturing the color cathode ray tube according to the present invention.

FIG. 5 is an explanatory view of another manufacturing method of the color cathode ray tube according to the present invention.

FIG. 6 is an explanatory view of another manufacturing method of the color cathode ray tube according to the present invention.

FIG. 7 is an explanatory view of another method of manufacturing a color cathode ray tube according to the present invention.

FIG. 8 is an explanatory view of another method of manufacturing the color cathode ray tube according to the present invention.

FIG. 9 is a schematic sectional view showing a color cathode ray tube.

10 is a view showing a mask frame used in the color cathode ray tube shown in FIG.

11 is a cross-sectional view taken along the line AA of FIG.

12 is a cut perspective view showing a part of the mask frame shown in FIG.

[Explanation of symbols]

 5 ... Mask frame 6 ... Shadow mask 15 ... Mask frame

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuichi Kijima 3300 Hayano, Mobara-shi, Chiba Hitachi Ltd. Mobara factory (72) Inventor Kawa ▲ saki Hiroshi 3681 Hayano, Mobara-shi, Chiba Hitachi Device Engineering Co., Ltd. Within

Claims (1)

[Claims] 1. A tension applied to a shadow mask,
A color cathode ray tube in which the shadow mask is attached to a mask frame, wherein the component of the shadow mask tension in the minor axis direction is made smaller than the component in the major axis direction.