JPH11250821A - Color cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color cathode-ray tube for displaying an image of good quality by preventing deformation of a shadow mask during operation of the color cathode-ray tube and setting or folding in pressing. SOLUTION: In a color cathode-ray tube comprising a substantially rectangular mask body 32 in which a portion 37 having no hole is disposed at the outer periphery of a substantially rectangular effective surface opposite to a phosphor screen and numerous electron beam passing holes 44 are formed at a substantially rectangular shadow mask and a skirt is bent at the outer peripheral portion by forming a bent portion 38 at the widthwise intermediate portion of the portion 37 having no hole, and a substantially rectangular mask frame fixed to the skirt portion, a band-like recess 43 is formed at the portion 37 having no hole in the mask body 32. In this way, during a long-term operation of the color cathode-ray tube, a stress generated in the mask body 32 by thermal expansion or a stress generated in pressing the mask body 32 can be inhibited by the band-like recess 43, thus preventing influence on the effective surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color cathode ray tube, and more particularly, to a color cathode ray tube in which deformation of a shadow mask is suppressed.

[0002]

2. Description of the Related Art In general, a color cathode ray tube is provided with a phosphor screen made of a three-color phosphor layer on an inner surface of an effective portion formed of a curved surface of a substantially rectangular panel, and is opposed to this phosphor screen at a predetermined interval. , A substantially rectangular shadow mask is arranged on the inside. Then, the three electron beams emitted from the electron gun disposed in the neck of the funnel are selected by using a shadow mask, and the phosphor screen is scanned to form a color image.

In such a color cathode ray tube, in order to display an image with good color purity on a phosphor screen, it is necessary to stably maintain a shadow mask in a predetermined relationship with respect to a panel. In particular, it is necessary to keep the distance between the inner surface of the effective portion of the panel and the shadow mask within a predetermined allowable range.

Normally, as shown in FIGS. 12 to 14, the shadow mask is formed with a large number of electron beam passage holes, and faces the phosphor screen 3 provided on the inner surface of the effective portion 2 of the panel 1. A non-porous portion 6 is provided on the outer periphery of a substantially rectangular effective surface 5 formed of a curved surface, and a middle portion in the width direction of the non-porous portion 6 is defined as a bent portion 7. Are formed by bending a substantially rectangular plate-shaped mask body 9 and a substantially rectangular mask frame 10 attached to the skirt portion 8.

In such a shadow mask, an electron beam passage hole is formed in a thin metal plate having a thickness of about 100 to 200 μm by photoetching to produce a flat mask, and then the mask main body 9 is formed by press molding. Then, the mask frame 10 is assembled to the skirt portion 8 of the mask body 9 by welding at a plurality of welding points. The non-porous portion 6 of the mask body 9 is provided with a notch 11 in order to relieve the drawing stress applied to the corner skirt portion 8 during press forming.

[0006]

As described above, in a color cathode ray tube, in order to display an image with good color purity on a phosphor screen, a shadow mask is stably provided to a panel in a predetermined relationship. Need to be held,
In particular, it is necessary to keep the distance between the inner surface of the effective portion of the panel and the shadow mask within a predetermined allowable range.

Normally, the shadow mask is provided with a non-porous portion on the outer periphery of an effective surface formed of a curved surface having a large number of electron beam passage holes formed therein. It is composed of a mask body having a skirt bent at its outer periphery and a mask frame attached to the skirt. Conventionally, the mask body is formed of a cold-rolled steel plate such as aluminum-killed steel having a plate thickness of about 100 to 200 μm, and a mask frame made of a cold-rolled steel plate having a greater plate thickness is attached to the skirt portion. Some have increased target strength.

However, when the mask main body is formed of a thin cold-rolled steel plate as described above, there is a problem in that when the color cathode ray tube is operated, thermal expansion occurs due to collision of an electron beam to deteriorate the image quality.

That is, during operation of the color cathode ray tube, less than one third of the electron beams emitted from the electron gun reach the phosphor screen through the electron beam passage holes of the shadow mask. Most of the electron beams collide with the mask body and heat the shadow mask. The thermal expansion of the shadow mask due to this heating is as follows: (a) At the beginning of the operation of the color cathode ray tube, the mask main body is mainly heated, and the mask frame is not heated so much. (B) Thermal expansion in which the effective surface 5 of the mask 9 bulges toward the phosphor screen 3 (b) Due to the collision of a high-density electron beam that locally displays a high-intensity image, the effective surface of the mask body is locally directed toward the phosphor screen. (C) When the color cathode ray tube is operated for a long time, the heat of the heated mask body is transmitted to the mask frame, so that the mask body and the mask frame are both heated and expanded.

[0010] Of these, the thermal expansion of (a) and (b) can be suppressed by forming the mask body with a low thermal expansion material such as Invar (Fe-Ni alloy). However, when the mask body is made of a low thermal expansion material, when the color cathode ray tube is operated for a long time, the thermal expansion amount of the mask frame made of a cold-rolled steel plate is larger than the thermal expansion amount of the mask body, The mask body 9 of the shadow mask 13 assembled as shown in FIG. 15A is pulled as shown in FIG.
The peripheral portion of the effective surface 5 is deformed (set), and the color purity is deteriorated due to the thermal expansion of (c).

The deformation of the mask body 9 can be prevented if the mask frame 10 is made of the same low thermal expansion material as the mask body 9, but since the mask frame 10 uses a larger amount of material than the mask body 9, Cannot be used for cost.

In the shadow mask, when a flat mask having an electron beam passage hole formed by photoetching is formed into a mask body by press molding, a draw and bending stress are applied to the corners, as shown in FIG. In addition, the electron beam passage hole 15 in the corner part extends,
There is a problem in that set-off and wrinkles 16 are generated on the skirt portion 8 of the corner.

The sag and wrinkles 16 at the corners of the skirt 8 can be alleviated to some extent by making the cuts 11 deep. However, if the cuts 11 are made too deep, the cuts may occur when the shadow mask is assembled. 11
A part of the opening becomes an aperture, and outside the image display area, a light emitting portion is formed by exposure light rays when forming a phosphor screen by a photographic printing method, and an electron beam collides when the color cathode ray tube operates. The problem of undesired light emission occurs.

The present invention has been made in view of the above-described problems, and prevents deformation of a shadow mask during operation of a color cathode ray tube, sag and wrinkles during press molding, and provides good quality. An object is to configure a color cathode ray tube for displaying an image.

[0015]

(1) A substantially rectangular shadow mask is disposed at a predetermined distance from a phosphor screen provided on the inner surface of a substantially rectangular panel, and the shadow mask passes through a large number of electron beams. A hole is formed in the outer periphery of the substantially rectangular effective surface facing the phosphor screen, and a non-perforated portion is provided on the outer periphery of the non-perforated portion. In a color cathode-ray tube comprising a substantially rectangular plate-shaped mask main body formed by bending and a substantially rectangular mask frame attached to a skirt portion of the mask main body, a band-shaped concave portion is formed in a non-porous portion of the mask main body. Formed.

(2) In the color cathode ray tube of (1), a band-shaped concave portion is formed in a bent portion of a non-porous portion.

(3) In the color cathode ray tube of (1), a mask frame is attached to the skirt portion of the mask body at a plurality of welding points, and a band-shaped concave portion is formed in a non-porous portion corresponding to the plurality of welding points.

(4) In the color cathode ray tube of (1), the band-shaped concave portion is formed so as to surround the vicinity of the corner of the effective surface.

(5) In the color cathode ray tube of (1), a band-shaped recess is formed at a corner of the skirt.

(6) In the color cathode ray tube according to any one of (1) to (5), a plurality of strip-shaped concave portions are formed in parallel.

(7) In the color cathode ray tube of (6), band-shaped concave portions are formed on both front and back surfaces of the non-porous portion.

(8) In the color cathode ray tube according to any one of (1) to (7), the strip-shaped recess is constituted by a plurality of dot-shaped recesses arranged in rows.

(9) In the color cathode ray tube of (8), a plurality of dot-shaped concave holes are independently formed.

(10) In the color cathode ray tube according to any one of (1) to (9), a band-shaped concave portion is formed in a continuous groove shape.

(11) In the color cathode ray tube according to any one of (1) to (10), the strip-shaped recess is an etching recess formed by photoetching.

[0026]

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

FIG. 1 shows a color cathode ray tube which is one embodiment of the present invention. This color cathode ray tube has an effective portion 20 having a curved surface.
Has an envelope composed of a substantially rectangular panel 22 provided with a skirt portion 21 at the periphery thereof, and a funnel-shaped funnel 23 joined to the skirt portion 21. On the inner surface of the effective portion 20 of the panel 22, three light emitting lights of blue, green and red are provided.
A phosphor screen 24 made of a color phosphor layer is provided. Further, a substantially rectangular shadow mask 25 described later is arranged inside the phosphor screen 24 so as to face the phosphor screen 24. On the other hand, an electron gun 28 that emits three electron beams 27B, 27G, and 27R is disposed in the neck 26 of the funnel 23. Then, the three electron beams 27B, 27G, and 27R emitted from the electron gun 28 are deflected by the deflecting device 30 mounted outside the funnel 23, and the phosphor screen 24 is horizontally and vertically scanned through the shadow mask 25. As a result, a structure for displaying a color image is formed.

The shadow mask 25 has a thickness of 100 to
A substantially rectangular mask body 32 made of a thin metal plate of about 200 μm, and a substantially rectangular mask frame 33 made of a metal having a thickness greater than that of the mask body 32,
The wedge-shaped elastic support members 34 attached to the corners of the mask frame 33 are supported on the inside of the panel 22 by engaging with stud pins 35 provided on the skirt portion 21 at each corner of the panel 22.

As shown in a developed view in FIG. 2, the mask body 32 has a plurality of electron beam passage holes formed therein, and a substantially rectangular effective surface 36 having a curved surface facing the phosphor screen. It comprises a non-porous portion 37 provided on the outer periphery of the effective surface 36, and a skirt portion 39 is formed on the outer peripheral portion of the non-porous portion 37 by bending a middle portion in the width direction as a bent portion 38. Reference numeral 40 denotes a notch provided at a portion of the skirt portion 39 which will be a corner portion.

The mask frame 33 is provided with the mask body 3
The second skirt portion 39 is attached by a plurality of spot weldings.

In particular, in this embodiment, as shown in FIG. 3, on the bent portion 38 of the surface of the non-porous portion 37 on the side of the phosphor screen, there is provided an independent portion which does not penetrate the plate thickness of the non-porous portion 37. A strip-shaped recess 43 made up of a plurality of dot-shaped recesses 42 is provided.

Such a concave hole 43 can be formed at the same time when the electron beam passing hole 44 is formed in a thin metal plate by photoetching.

That is, the electron beam passage holes 44 of the mask main body 32 are formed by forming a photoresist on both surfaces of a thin metal plate, and forming a pair of optical patterns in which a pattern corresponding to the electron beam passage holes 44 is formed on the photoresist on both surfaces. It is formed by exposing through a mask and baking the pattern of the optical mask on the photoresist on both sides, and then developing and etching. One of the optical masks is formed along with the pattern corresponding to the electron beam passage hole 44, By forming a pattern corresponding to the plurality of dot-shaped holes 42, the plurality of dot-shaped holes 42 can be formed as etching holes simultaneously with the electron beam passage holes 44.

When the band-shaped concave portion 43 is provided on the bent portion 38 of the non-porous portion 37 surrounding the outer periphery of the mask body 32 as described above, the mask body 32 is made of a low thermal expansion material such as amber and the like, and the mask frame 33 is made of In the case of a cold-rolled steel plate, when the color cathode ray tube is operated for a long time, the heat of the mask main body 32 heated by the collision of the electron beams 27B, 27G, and 27R emitted from the electron gun 28 causes the heat of the mask frame 3.
3 and the thermal expansion of the mask frame 33, FIG.
In the case where the mask frame 33 does not thermally expand in (a), as shown in the case of thermal expansion in (b), the bent portion 38 has a hinge structure, and the thermal expansion of the mask frame 33 causes Even if the skirt portion 39 is inclined, the bending moment caused by the inclination is effective surface 36.
The deformation of the effective surface due to the thermal expansion of the mask frame shown in FIG.

Next, a mask body having a different configuration will be described.

The mask body 32 shown in FIG.
The band-shaped concave portions 43 are formed in three rows along the bent portion 38 on and near the bent portion 38 on the surface of the phosphor screen side. The strip-shaped recess 4
Reference numeral 3 denotes a plurality of independent dot-shaped recesses 42 which do not penetrate the thickness of the non-porous portion 37, and the dot-shaped recesses 42 are arranged in a staggered manner between three rows of band-shaped recesses 43. ing.

Even with such a configuration, a shadow mask having the same effect as the mask body shown in FIG. 3 can be formed.

The mask body 32 shown in FIG. 6 has a band-shaped recess 43 along the bent portion 38 on and near the bent portion 38 on the phosphor screen side surface of the non-porous portion 37. Are formed in three rows. Each of the band-shaped concave portions 43 is formed in a continuous groove shape that does not penetrate the plate thickness of the non-porous portion 37.

Even with such a configuration, a shadow mask having the same effect as the mask body shown in FIG. 3 can be formed.

The mask body 32 shown in FIG.
The band-shaped concave portions 43 are formed in one line on the bent portion 38 on the surface of the phosphor screen side, and two lines are formed along the bent portion 38 near the bent portion 38 on the opposite surface. The strip-shaped concave portion 43 is constituted by a plurality of independent dot-shaped concave holes 42 that do not penetrate the plate thickness of the non-porous portion 37.

Even with such a configuration, a shadow mask having the same effect as the mask body shown in FIG. 3 can be formed.

The mask main body 32 shown in a developed view in FIG. 8 is welded to the mask frame with an X mark 46 shown at the corner of the skirt portion 39 and in the middle of each side. Particularly, in the illustrated example, a band-shaped concave portion 43 is formed on the bent portion 38.

As described above, a shadow mask having the same effect as that of the mask body shown in FIG. 3 can be formed only by forming the band-shaped recess 43 corresponding to the welding point between the mask body 32 and the mask frame 33. Can be.

The mask main body 32 shown in a developed view in FIG. 9 has two rows of groove-shaped band-shaped concave portions 43 connected to the non-hole portions 37 along the corners of the effective surface 36 on the surface on the phosphor screen side. On the opposite side of the bent portion 38, one continuous groove-shaped strip-shaped concave portion 43 is formed in a total of three rows.

When the band-shaped recess 43 is formed along the corner of the effective surface 36 in this manner, a flat mask having the electron beam passage holes 44 formed by photoetching is formed into a mask body by press forming. At this time, the force in the direction of the arrow 47 applied to the corner portion can be absorbed by the band-shaped concave portion 43 so as not to reach the corner portion of the effective surface 36. Therefore, with the above-described configuration, it is possible to reduce the elongation of the electron beam passage hole 44 at the corner part (see FIG. 17) which has conventionally occurred.

The mask main body 32 shown in a developed view in FIG.
On both sides near the notch 40 at the corner of the non-porous portion 37,
The belt-shaped recesses 43 are formed of a plurality of independent dot-shaped recesses 42 that do not pass through the plate thickness, and are formed in two rows, for a total of four rows.

When the band-shaped concave portion 43 is formed in the vicinity of the cut 40 at the corner of the non-porous portion 37, the intermediate portion in the width direction of the non-porous portion 37 is bent by press molding as shown in FIG. When the skirt portion 39 is formed by bending the skirt portion 39 at the portion 38, it is possible to reduce the occurrence of settling and wrinkling at the corner of the skirt portion 39.

[0048]

As described above, when the band-shaped concave portion is formed in the non-porous portion surrounding the outer periphery of the effective portion of the mask body, the mask frame is generated in the mask body due to thermal expansion when the color cathode ray tube is operated for a long time. Stress, or the stress generated during press forming of the mask body, is blocked by the band-shaped recess,
The effective portion can be prevented from being affected, and a color cathode ray tube that displays a high-quality image can be configured.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a color cathode ray tube according to an embodiment of the present invention.

FIG. 2 is an expanded view of a mask main body of the shadow mask of the color cathode ray tube.

FIG. 3 (a) is a plan view showing an expanded configuration of a main part of the mask main body, and FIG. 3 (b) is a sectional view thereof.

4 (a) and 4 (b) are views for explaining the operation and effect of the mask main body, FIG. 4 (a) is a view when the mask frame does not thermally expand, and FIG. 4 (b) Is a diagram when thermal expansion has occurred.

FIG. 5A is a plan view showing an expanded configuration of a main part of a different mask body, and FIG. 5B is a sectional view thereof.

FIG. 6A is a plan view showing a main part of another different mask body in a developed state, and FIG. 6B is a sectional view thereof.

FIG. 7A is a plan view showing a main part configuration of another different mask body in a developed state, and FIG. 7B is a sectional view thereof.

FIG. 8 is a view showing another mask main body in a developed state.

FIG. 9A is a plan view showing a main part configuration of another different mask main body in a further developed manner, and FIG. 9B is a BB view thereof.
It is sectional drawing.

FIG. 10 (a) is a plan view showing a main part configuration of another different mask main body, which is further developed, and FIG. 10 (b) is a BB cross-sectional view thereof.

FIG. 11 is a view for explaining an effect exerted by the mask main body shown in FIG. 10;

FIG. 12 is a view showing a relationship between a shadow mask and a panel of a conventional color cathode ray tube.

FIG. 13 is an expanded view of a conventional mask main body.

FIG. 14 is an exploded perspective view showing a conventional shadow mask.

FIGS. 15A and 15B are diagrams for explaining the problem of the above-mentioned conventional shadow mask.
(A) is a view when the mask frame does not thermally expand, FIG.
FIG. 5 (b) is a view when thermal expansion is performed.

FIG. 16 is a view for explaining a problem of the conventional shadow mask.

[Explanation of symbols]

 Reference Signs List 22 panel 24 phosphor screen 25 shadow mask 32 mask body 33 mask frame 37 non-porous part 38 bent part 39 skirt part 42 tot-shaped concave hole 43 band-shaped concave part 44 electron beam passage Hole

Claims (11)

[Claims] 1. A substantially rectangular shadow mask is disposed at a predetermined distance from a phosphor screen provided on the inner surface of a substantially rectangular panel, and the shadow mask has a large number of electron beam passage holes formed therein. A non-porous portion was provided on the outer periphery of the substantially rectangular effective surface facing the screen, and a skirt portion was formed by bending the middle portion in the width direction of the non-porous portion as a bent portion. In a color cathode ray tube comprising a substantially rectangular plate-shaped mask main body and a substantially rectangular mask frame attached to a skirt portion of the mask main body, a strip-shaped concave portion is formed in a non-porous portion of the mask main body. A color cathode ray tube characterized by the above. 2. A color cathode ray tube according to claim 1, wherein a band-shaped concave portion is formed in a bent portion of the non-porous portion. 3. A mask frame is attached to a skirt portion of a mask body at a plurality of welding points, and a band-shaped recess is formed in a non-porous portion corresponding to the plurality of welding points. The color cathode ray tube as described. 4. The color cathode ray tube according to claim 1, wherein the band-shaped recess is formed so as to surround the vicinity of the corner of the effective surface. 5. The color cathode ray tube according to claim 1, wherein a band-shaped recess is formed at a corner of the skirt. 6. The color cathode ray tube according to claim 1, wherein a plurality of strip-shaped concave portions are formed in parallel. 7. The color cathode ray tube according to claim 6, wherein a strip-shaped concave portion is formed on both front and back surfaces of the non-porous portion. 8. The color cathode ray tube according to claim 1, wherein the band-shaped concave portion comprises a plurality of dot-shaped concave holes arranged in a row. 9. The color cathode ray tube according to claim 8, wherein a plurality of dot-shaped concave holes are formed independently of each other. 10. The color cathode ray tube according to claim 1, wherein the band-shaped concave portion is formed in a continuous groove shape. 11. The color cathode ray tube according to claim 1, wherein the strip-shaped recess is formed by an etching recess formed by photoetching.