JP2000133160A - Color picture tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color picture tube resisting deterioration of color purity by enhancing the strength for retaining the curved surface of a mask body to reduce the shift of beam landing. SOLUTION: This color picture tube, has a generally rectangular shadow mask 30 that comprises an effective surface 32 made of a curved surface opposite to a phosphor screen, a mask body 35 consisting of an unperforated part 33 surrounding the effective screen and a skirt part 34 formed by curving the outer periphery thereof, and a mask frame 36 mounted on the skirt part. A structure in which the radius of curvature of the effective surface of the mask body, in the direction of at least either a minor or major axis, is at its minimum in the vicinity of a position halfway between the center and the circumference of the effective surface is adopted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color picture tube in which a curved surface holding strength of a shadow mask is increased to reduce a beam landing deviation, and more particularly to a color picture tube which is effective when applied to a shadow mask having a large radius of curvature. .

[0002]

2. Description of the Related Art In general, as shown in FIG. 4, a color picture tube is joined to a substantially rectangular panel 3 provided with a side wall 2 around a curved effective portion 1 and the side wall 2. A funnel-shaped funnel 4 having a vacuum envelope,
On an inner surface of the effective portion 1 of the panel 3, a phosphor screen 5 including a black non-light-emitting layer and a three-color phosphor layer formed so as to be embedded in a gap between the black non-light-emitting layers is provided. Further, a substantially rectangular shadow mask 6 is disposed inside the phosphor screen 5 so as to face the phosphor screen 5. On the other hand, three electron beams 9 are placed in the neck 8 of the funnel 4.
An electron gun 10 for emitting B, 9G, 9R is provided. Then, the three electron beams 9B, 9G, 9R emitted from the electron gun 10 are deflected by the deflecting device 12 mounted outside the funnel 4, and the phosphor screen 5 is horizontally and vertically scanned through the shadow mask 6. As a result, a structure for displaying a color image is formed.

The shadow mask 6 is for selecting three electron beams 9B, 9G, and 9R emitted from the electron gun 10 with respect to a three-color phosphor layer constituting the phosphor screen 5. As shown in FIG. 5, a large number of electron beam passage holes 13 are formed, an effective surface 14 having a curved surface facing the phosphor screen, a non-porous portion 15 surrounding the outer periphery of the effective surface 14, and the non-porous portion 15 A substantially rectangular mask body 17 comprising a skirt portion 16 bent substantially at right angles to the outer periphery of the mask body 17;
And a substantially rectangular mask frame 18 attached to the mask frame 18. Then, as shown in FIG. 4, the wedge-shaped elastic support members 20 attached to the respective corners of the mask frame 18 are engaged with stud pins 21 provided at the corners of the side wall 2 of the panel 3. Thereby, it is detachably supported inside the panel 3.

Generally, a phosphor screen 5 of a color picture tube is used.
In order to display an image without color shift on top, it is necessary to use three electron beams 9 passing through the electron beam passage holes 13 of the mask body 17.
B, 9G, and 9R must be sorted so that the three-color phosphor layers land properly. For that, Panel 3
Correct the positional relationship between the shadow mask 6 and
The inner surface of the effective portion 1 of the panel 3 and the effective surface 14 of the mask body 17
(Q value) must be within a predetermined allowable range.

In recent years, in order to improve the visibility of a color picture tube, it has been demanded that the radius of curvature of the outer surface of the effective portion 1 of the panel 3 be increased so as to be closer to a flat surface. In such a panel 3, it is necessary to increase the radius of curvature of the inner surface of the effective portion 1 in view of the atmospheric pressure intensity and visibility of the vacuum envelope, and with the increase in the radius of curvature of the inner surface of the effective portion 1, In order to obtain an appropriate beam landing, it is necessary to increase the radius of curvature of the effective surface 14 of the shadow mask 6.

However, when the radius of curvature of the effective surface 14 of the shadow mask 6 is increased, the curved surface holding strength is reduced, and local deformation occurs in the manufacturing process of the shadow mask 6 and thermal deformation occurs in the manufacturing process of the color picture tube. The beam landing is shifted, and the color purity is likely to deteriorate. When a color picture tube is incorporated in a receiver, sound from a speaker causes the shadow mask 6 to resonate, and the resonance tends to cause deterioration (howling) of color purity.

As a measure for improving the curved surface holding strength of the shadow mask 6, Japanese Patent Laid-Open No. 7-161306 proposes providing a reinforcing bead on the effective surface.

However, when a reinforcing bead is provided on an effective surface having a large radius of curvature so as to obtain a sufficient curved surface holding strength, the gap between the inner surface of the effective portion of the panel and the effective surface of the shadow mask is locally reduced. Detachment, the image of the step formed by the formation of the reinforcing bead appears on the screen, and the image quality is remarkably deteriorated. Therefore, the height of the reinforcing bead has a limit, usually about 0.1 to 0.2 mm, and the curved surface holding strength cannot be sufficiently increased.

[0009]

As described above, in the color picture tube, when the radius of curvature of the outer surface of the effective portion of the panel is made larger and closer to a flat surface in order to improve the visibility, the inner surface of the effective portion also has a radius of curvature. Must be increased, and accordingly, the radius of curvature of the effective surface of the shadow mask needs to be increased. However, if the radius of curvature of the effective surface of the shadow mask is increased, the curved surface holding strength is reduced, and local deformation in the shadow mask manufacturing process and thermal deformation in the color picture tube manufacturing process are likely to occur. And the color purity is degraded. In addition, when a color picture tube is incorporated in a receiver, there is a problem that sound from a speaker resonates the shadow mask, and the resonance tends to cause deterioration in color purity.

As a measure for improving the curved surface holding strength of the effective surface of the mask body having a large radius of curvature, there is a proposal to provide a reinforcing bead on the effective surface. However, a sufficient curved surface holding strength can be obtained on the effective surface having a large radius of curvature. If a reinforcement bead is provided in
The distance between the inner surface of the effective portion of the panel and the effective surface of the mask body is locally out of the allowable range, and an image of a step formed by the formation of the reinforcing beads appears on the screen, and the image quality is significantly deteriorated. Therefore, in a shadow mask having a large radius of curvature of the effective surface, there is a problem that the curved surface holding strength cannot be sufficiently increased by the reinforcing beads.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a color picture tube in which the strength of holding a curved surface of a mask body is increased to reduce beam landing deviation, and color purity is hardly deteriorated. With the goal.

[0012]

(1) A substantially rectangular shadow mask is arranged to face a phosphor screen formed on the inner surface of an effective portion of a substantially rectangular panel, and this shadow mask is composed of a large number of electron beams. A substantially rectangular mask body including a curved surface having a through hole formed therein and a curved surface facing the phosphor screen, a non-porous portion surrounding the effective surface, and a skirt portion formed by bending the outer periphery of the non-porous portion; A color picture tube having a substantially rectangular mask frame attached to a skirt portion of the mask body, wherein at least one of the radius of curvature of the effective surface of the mask body in the short axis direction and the long axis direction is set to the center of the effective surface. The structure is minimized near the middle of the area.

(2) A substantially rectangular shadow mask is disposed to face the phosphor screen formed on the inner surface of the effective portion of the substantially rectangular panel. A substantially rectangular mask body comprising an effective surface formed of a curved surface facing the body screen, a non-porous portion surrounding the effective surface, and a skirt portion formed by bending the outer periphery of the non-porous portion; and a skirt of the mask main body In a color picture tube having a substantially rectangular mask frame attached to a portion, an outer surface of an effective portion of a panel has a radius of curvature of 10 m or more, and a short-axis direction and a long-axis direction of an effective surface of a mask body with respect to this panel. At least one of the radii of curvature is minimized near the middle between the center and the periphery of the effective surface.

(3) In the color picture tube of (1) or (2), the radius of curvature of the effective surface of the mask body in the major axis direction is minimized near the center in the major axis direction.

(4) In the color picture tube of (3),
The minimum radius of curvature in the major axis direction was provided in an area of 乃至 to ／ of the distance from the center of the effective surface to the major axis end.

(5) In the color picture tube of (4),
The minimum radius of curvature in the major axis direction extends in the minor axis direction to a position near the middle between the minor axis and the major side of the effective surface.

(6) In the color picture tube of (1) or (2), the radius of curvature of the effective surface of the mask body in the minor axis direction is minimized near the middle in the minor axis direction.

(7) In the color picture tube of (6),
The minimum radius of curvature in the minor axis direction was provided in an area of １ ／ to ／ of the distance from the center of the effective surface to the minor axis end.

(8) In the color picture tube of (6),
The structure is such that the minimum radius of curvature in the minor axis direction extends in the major axis direction to near the middle between the major axis and the minor side of the effective surface.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 shows a color picture tube as one embodiment of the present invention. The color picture tube has a side wall 2 around the effective portion 1.
Is provided, and a vacuum envelope including a funnel-shaped funnel 4 joined to the side wall 2 of the panel 3 is provided. The inner surface of the effective portion 1 of the panel 3 includes a black non-light-emitting material layer and a three-color phosphor layer which emits blue, green, and red light and is provided so as to be embedded in a gap between the black non-light-emitting material layers. A phosphor screen 5 is provided. A substantially rectangular shadow mask 30 is arranged inside the phosphor screen 5 so as to face the phosphor screen 5. On the other hand, three electron beams 9B, 9G, 9R are placed in the neck 8 of the funnel 4.
Is provided. The three electron beams 9B, 9G, 9 emitted from the electron gun 10
R is deflected by the magnetic field generated by the deflecting device 12 mounted on the outside of the funnel 4 to scan the phosphor screen 5 horizontally and vertically through the shadow mask 30,
It is formed in a structure for displaying a color image.

As shown in FIG. 1, the shadow mask 30 has a large number of electron beam passage holes 31 formed therein, and has an effective surface 32 formed of a curved surface facing the phosphor screen, and surrounds the outer periphery of the effective surface 32. A non-porous portion 33 and a skirt portion 34 bent substantially at right angles to the outer periphery of the non-porous portion 33
And a substantially rectangular mask frame 36 attached to the skirt portion 34 of the mask body 35. And FIG.
As shown in FIG. 3, the wedge-shaped elastic support 20 attached to the corner of the mask frame 36 is engaged with the stud pin 21 provided at the corner of the side wall 2 of the panel 3 so that the panel 3 It is detachably supported inside.

Particularly, in this embodiment, the effective surface 32 of the mask body 35 is formed into a curved surface having the smallest radius of curvature near the center between the center and the periphery.
That is, in the major axis (X-axis) direction, the radius of curvature of the region 38 near the center between the center of the effective surface 32 and the end of the major axis becomes the smallest near the middle between the major axis and the major side. ing. In the short axis (Y axis) direction, the radius of curvature of the region 39 near the center between the center of the effective surface 32 and the short axis end is the smallest up to the middle part between the short axis and the short side. ing. Area 3
8 is preferably in the range of 乃至 to ／ of the distance from the center of the effective surface 32 to the long axis end, and for the region 39, 1 is the distance from the center of the effective surface 32 to the short axis end. / 2
To 3/4.

FIGS. 3A and 3B show examples of the radius of curvature in the major axis direction on the major axis of the effective surface and the radius of curvature in the minor axis direction on the minor axis, respectively, by curves 40 and 41, respectively.

The curved surface of the effective surface 32 having such a radius of curvature is expressed by the following equation (1) having three orthogonal axes including the major axis, the minor axis, and the tube axis (Z axis) having the origin at the center of the effective surface 32. The coefficient C (i, j) is represented by a polynomial expression shown in Table 1.
It can be realized by selecting as follows.

[0026]

(Equation 1)

[0027]

[Table 1]

Even if the effective surface of the mask body is configured as described above, the drop of the peripheral portion with respect to the center of the effective surface in the tube axis direction is determined by a predetermined distance between the inner surface of the effective portion of the panel and the effective surface of the mask body. q value).

For example, the radius of curvature in the major axis direction on the major axis at the center of the effective plane is about 5500 mm, the radius of curvature in the major axis direction at the middle part in the major axis direction is about 2500 mm, and the minor axis direction on the minor axis at the center of the effective plane. When the radius of curvature is 1250 mm, and the radius of curvature in the short axis direction at the middle part in the short axis direction is about 700 mm, which is the minimum, the drop of the long axis end to the center of the effective surface is about 10 mm, and the drop of the short axis end is Approximately 12mm, diagonal shaft end drop is approximately 13mm
Thus, the distance between the panel and the inner surface of the effective portion can be kept within an allowable range.

Therefore, when the shadow mask 30 is configured as described above, even if an impact is applied in the tube axis direction after the manufacturing process of the color picture tube or after the manufacture is completed, the effective surface 32 can be hardly depressed.

That is, when the color picture tube receives an impact, the inertial force applied to the shadow mask increases in proportion to the weight of the mask body from the portion where the inertial force is applied to the center of the mask body, that is, the area of the mask body. Become. on the other hand,
The local curved surface holding strength with respect to the inertial force of the effective surface of the mask body increases as the radius of curvature decreases.

Therefore, the effective surface 32 of the mask body 35
Near the center of, because of the small area, the inertial force is small,
Deformation hardly occurs even if the radius of curvature is large. Further, in the shadow mask 30 of this embodiment, the mask body 35
Since the radius of curvature near the middle of the effective surface 32 is small, deformation near the middle of the effective surface 32 is unlikely to occur. In the vicinity of the effective surface 32, the inertial force due to the weight of the entire effective surface 32 is applied, and the inertia force is maximized. However, around the effective surface 32, a non-porous portion 33 and a skirt portion 34 bent at substantially a right angle are formed. Therefore, deformation around the effective surface 32 is unlikely to occur.

That is, when the radius of curvature near the middle of the effective surface 32 of the mask body 35 is reduced as described above, the effective surface 3
(2) It is possible to make it difficult for large depression deformation to occur over the entire surface.

Therefore, when the shadow mask 30 is constructed as in this embodiment, the radius of curvature of the outer surface of the effective portion 1 of the panel 3 is increased to make it closer to a flat surface in order to improve visibility, and accordingly, the mask body is The present invention is applied to a shadow mask that reduces the depth of the effective surface 32 around the effective surface 32 to increase the curved surface holding strength over the entire effective surface 32 without locally forming a portion where the curved surface holding strength is reduced, thereby manufacturing a color picture tube. It is possible to prevent local deformation of the shadow mask due to impact applied after the process or the end of manufacturing. Also, when a color picture tube is incorporated in a receiver,
Howling due to resonance with the sound from the speaker can also be suppressed, and a color picture tube with less deterioration in color purity can be obtained.

In the above embodiment, the case where the radius of curvature near the middle of the effective surface of the mask body is minimized in both the major axis and the minor axis has been described. A similar effect can be obtained by applying the present invention to a mask body having a curvature mainly in any one direction of the axis when one of the major axis and the short axis has the above-described radius of curvature.

[0036]

As described above, when the shadow mask is formed, the curved surface holding strength is increased over the entire effective surface without forming a portion where the curved surface holding strength is locally reduced on the effective surface of the mask body, and the color picture tube is formed. Can prevent local deformation of the shadow mask due to the impact applied after the manufacturing process or after the end of manufacturing.In addition, when a color picture tube is incorporated in the receiver, howling due to resonance with the sound from the speaker can be suppressed. In addition, a color picture tube in which color purity is hardly deteriorated can be obtained. Accordingly, a large effect can be obtained particularly when applied to a shadow mask in which the radius of curvature of the outer surface of the effective portion of the panel is increased to make it closer to a flat surface, and accordingly, the drop around the effective surface of the mask body becomes smaller.

[Brief description of the drawings]

FIG. 1A is a plan view showing a configuration of a shadow mask of a color picture tube according to an embodiment of the present invention; FIG.
(B) is the front view shown by the cross section.

FIG. 2 is a diagram showing a configuration of a color picture tube according to an embodiment of the present invention.

FIG. 3A is a view showing a radius of curvature in a major axis direction on a major axis of an effective surface of the mask body of the shadow mask, and FIG. 3B is a minor axis in a minor axis direction on a minor axis; It is a figure showing a radius of curvature.

FIG. 4 is a diagram showing a configuration of a conventional color picture tube.

FIG. 5A is a plan view showing a configuration of a shadow mask of a conventional color picture tube, and FIG. 5B is a front view showing a cross section.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Effective part 3 ... Panel 5 ... Phosphor screen 30 ... Shadow mask 32 ... Effective surface 33 ... Non-porous part 34 ... Skirt part 35 ... Mask body 36 ... Mask frame

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masayo Inoue 1-9-2 Hara-cho, Fukaya-shi, Saitama F-term in Toshiba Fukaya Electronics Factory Co., Ltd. 5C031 EE01

Claims (8)

[Claims] 1. A substantially rectangular shadow mask is disposed to face a phosphor screen formed on an inner surface of an effective portion of a substantially rectangular panel, and the shadow mask has a large number of electron beam passage holes formed therein. A substantially rectangular mask body comprising an effective surface formed of a curved surface facing the body screen, a non-porous portion surrounding the effective surface, and a skirt portion formed by bending the outer periphery of the non-porous portion; and a skirt of the mask main body A color picture tube having a substantially rectangular mask frame attached to the portion, wherein at least one of the radii of curvature in the short axis direction and the long axis direction of the effective surface of the mask body is the center of the effective surface, in the short axis direction, and A color picture tube characterized in that it is minimum near the middle of each of the major axis directions. 2. A substantially rectangular shadow mask is disposed to face a phosphor screen formed on an inner surface of an effective portion of a substantially rectangular panel, and the shadow mask has a large number of electron beam passage holes formed therein. A substantially rectangular mask body comprising an effective surface formed of a curved surface facing the body screen, a non-porous portion surrounding the effective surface, and a skirt portion formed by bending the outer periphery of the non-porous portion; and a skirt of the mask main body A color picture tube having a substantially rectangular mask frame attached to a portion, wherein the panel has an outer surface of the effective portion having a radius of curvature of 10 m or more, and the mask body has a short axis of the effective surface. The radius of curvature of at least one of the direction and the major axis direction is minimum near the middle between the center of this effective surface and the periphery in the minor axis direction and major axis direction. A color picture tube. 3. The color picture tube according to claim 1, wherein the radius of curvature of the effective surface of the mask body in the major axis direction is minimum near the center in the major axis direction. 4. The apparatus according to claim 3, wherein the minimum radius of curvature in the major axis direction is provided in an area of 乃至 to ／ of the distance from the center of the effective surface to the major axis end. Color picture tube. 5. The color picture tube according to claim 4, wherein the portion having the smallest radius of curvature in the major axis direction extends in the minor axis direction to near the middle between the minor axis and the major side of the effective surface. 6. The color picture tube according to claim 1, wherein the radius of curvature of the effective surface of the mask body in the minor axis direction is minimum near the middle in the minor axis direction. 7. The device according to claim 6, wherein the minimum radius of curvature in the minor axis direction is provided in an area of 乃至 to ／ of the distance from the center of the effective surface to the minor axis end. Color picture tube. 8. The color picture tube according to claim 7, wherein the minimum radius of curvature in the minor axis direction extends in the major axis direction to near the middle between the major axis and the minor side of the effective surface.