JP2002050302A - Color cathode ray tube - Google Patents

Abstract

[Problem] To provide a color cathode ray tube with improved image quality by reducing deterioration of color purity due to deformation and displacement of a shadow mask. Skirt part 14, mask body 15 having major and minor axes
And the mask frame 16 located outside the skirt portion
And the mask frame has a larger coefficient of thermal expansion than the mask body. The skirt includes a first tongue piece 26a located on the short axis and a second tongue piece 2 located on the long axis.
6b, and the first and second tongue pieces are fixed to the mask frame. The length of the first tongue piece is Ca, the width is Wa, the length of the second tongue piece is Cb, the width is Wb, the length in the major axis direction of the mask main surface is H, and the length in the minor axis direction is H. When V is set, the mask body is formed so as to satisfy the following relationship. (Ca · Wb) <(Cb · Wa), and V <H

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 having a shadow mask.

[0002]

2. Description of the Related Art Generally, a color cathode ray tube is provided with a vacuum envelope having a panel and a funnel. The panel has a substantially rectangular effective portion having a curved inner and outer surface, and a skirt provided upright around the effective portion, and the funnel is joined to the skirt. On the inner surface of the panel effective portion, a substantially rectangular fluorescent light having a black non-light-emitting layer and a three-color phosphor layer provided in the gap between the black non-light-emitting layers and emitting blue, green, and red light. A body screen is provided. Further, a substantially rectangular shadow mask is arranged to face the phosphor screen. On the other hand, an electron gun that accelerates, focuses, and emits three electron beams is disposed in the neck of the funnel.

In the above color cathode ray tube, the three electron beams emitted from the electron gun are deflected by a magnetic field generated by a deflection yoke mounted outside the funnel, and the phosphor screen is horizontally and vertically deflected via a shadow mask. A color image is displayed by scanning.

[0004] The shadow mask includes a mask body and a mask frame. The mask body has a substantially rectangular mask main surface having a curved surface facing the phosphor screen and a skirt portion formed by bending a peripheral portion of the mask main surface, and a large number of electron beams are formed on the mask main surface. The passage holes are formed in a predetermined arrangement. The mask frame is welded to the skirt of the mask body. And the shadow mask is formed by each electron beam passage hole of the mask body.
An electron beam landing on the three-color phosphor layer is selected.

In order to display an image without color shift on the phosphor screen, it is necessary to maintain each electron beam passage hole of the mask body and a phosphor layer corresponding to the electron beam passage hole in a specific positional relationship. During the operation of the color cathode ray tube, it is necessary to keep the positional relationship, in particular, the distance (q value) between the mask main surface of the mask body and the inner surface of the panel within a predetermined allowable range.

On the other hand, during operation of the color cathode ray tube, an electron beam reaching the phosphor screen through each electron beam passage hole of the mask body is one third or less of the total electron beam emitted from the electron gun. The remaining electron beam collides with a portion other than the electron beam passage hole of the mask main body, is converted into thermal energy, and heats the mask main body. By this heating, the mask body thermally expands, and so-called doming, which swells in the direction of the phosphor screen, occurs.

If the distance between the mask main surface of the mask body and the panel inner surface exceeds a predetermined allowable range due to the doming, the landing position of the electron beam with respect to the phosphor layer shifts, and the color purity deteriorates. The landing deviation of the electron beam with respect to the phosphor layer greatly changes depending on the brightness of the image pattern and the duration.

In recent years, the color cathode ray tube has a wider deflection angle with an increase in size, and on the other hand, a flat screen has been promoted.
In such a color cathode ray tube, the deterioration of the color purity due to the thermal expansion of the mask body becomes more remarkable. Therefore, in a large color cathode ray tube having a flat screen, an invar material (36% Ni-Fe alloy) having a low coefficient of thermal expansion is often used for a mask body. In this case, in order to avoid an increase in the cost of the shadow mask, a cold-rolled steel plate that is less expensive than the invar material is often used for the mask frame.

[0009]

However, when the mask body is formed of amber material and the mask frame is formed of a cold-rolled steel plate as described above, the color cathode ray tube operates for a long time,
The heat of the mask body is transmitted to the mask frame, and the mask frame thermally expands. In this case, due to the difference in thermal expansion between the mask body having a low coefficient of thermal expansion and the mask frame having a high coefficient of thermal expansion,
The mask body is deformed by being pulled by the mask frame. Further, in the manufacturing process of the color cathode ray tube, since the shadow mask is heated to a higher temperature than the heat generated due to the collision of the electron beam, the difference in thermal expansion between the mask body and the mask frame becomes large, and the mask body becomes Deforms more.

In order to reduce deformation of the mask body due to a difference in thermal expansion between the mask body and the mask frame, a skirt portion of the mask body is arranged inside the mask frame, and a tongue piece provided on the skirt portion is attached to the mask frame. Is provided. With this configuration, when the mask body is pulled by the mask frame, the tongue piece elastically deforms to absorb the tensile force of the mask frame, thereby reducing the deformation of the mask main surface.

However, even if the shadow mask is formed as described above, in a large color cathode ray tube, the shadow mask also becomes large, and the difference in the amount of extension between the mask body and the mask frame due to the difference in thermal expansion increases. The tensile force and the amount of tension of the mask frame increase proportionally.
Further, in a color cathode ray tube having a flat screen, the curvature of the main surface of the mask of the mask body is small, and the curved surface holding strength is smaller than that of a conventional shadow mask. for that reason,
Even when the pulling force is small, the mask main surface is deformed. Therefore, in such a shadow mask, it is necessary to reduce the tensile force acting on the mask main surface as much as possible.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to provide a color cathode ray tube in which the deterioration of color purity due to the deformation and displacement of a shadow mask is reduced and the image quality is improved. is there.

[0013]

In order to suppress the deformation due to the difference in thermal expansion between the mask body and the mask frame, it is desirable to make the tongue piece of the skirt portion of the mask body as deformable as possible. Such a tongue piece is obtained by narrowing the width and increasing the length.

However, in this case, the tongue piece is easily deformed in the width direction, and the mask main body is displaced in the direction perpendicular to the tube axis inside the mask frame in response to an impact or vibration acting in the width direction. As a result, the landing on the phosphor layer shifts, and the color purity deteriorates. Further, in the phosphor screen forming process, the phosphor layer is exposed using the shadow mask as an optical mask, so that the attachment / detachment of the shadow mask to the panel is repeated a plurality of times. The mask body is displaced by such a detachment operation, the position of the phosphor layer to be formed is displaced, and a desired phosphor screen cannot be formed.

In particular, recently, there has been an increasing demand for high-quality images, and the arrangement pitch of the phosphor layers has been reduced in order to increase the resolution. Therefore, the landing margin of the electron beam is small, and more accurate beam landing is required.

Therefore, the color cathode ray tube according to the present invention has a panel having a substantially rectangular effective portion, a tube axis, a long axis perpendicular to the tube axis, and a tube axis and a long axis. An envelope having a short axis extending orthogonally, and a phosphor screen having a plurality of phosphor layers formed on an inner surface of the effective portion and each extending along a direction substantially parallel to the short axis. A shadow mask provided in an envelope facing the phosphor screen, and an electron gun provided in the envelope and irradiating the phosphor screen with an electron beam through the shadow mask, It has.

The shadow mask is a substantially rectangular mask main surface facing the phosphor screen and having a large number of electron beam passage holes formed thereon, and a skirt bent around the mask main surface. And a substantially rectangular mask body having a major axis and a minor axis corresponding to the major and minor axes, and a substantially rectangular mask body attached to the skirt and located outside the skirt. A mask frame, wherein the mask frame has a larger coefficient of thermal expansion than the mask body.

A skirt portion of the mask main body, the first tongue piece portion being located on the short axis and extending along the tube axis direction;
A second tongue piece positioned on the long axis and extending along the tube axis direction, wherein the first and second tongue pieces each have a free end and are fixed to the mask frame; The length of the first tongue piece along the tube axis direction is Ca, the width of the first tongue piece is Wa, and the length of the second tongue piece along the tube axis direction is C.
b, when the width of the second tongue piece is Wb, the length in the major axis direction of the mask is H, and the length in the minor axis is V, the mask body is formed to satisfy the following relationship. Have been. (Ca · Wb) <(Cb · Wa), and V <H According to the color cathode ray tube of the present invention, the mask body is formed so as to satisfy the following relationship. (Ca · Wb) / (Cb · Wa) ≦ V / H According to the color cathode ray tube according to the present invention configured as described above, when the shadow mask is heated, the mask body having a small coefficient of thermal expansion is: It is pulled by the mask frame having a large coefficient of thermal expansion. At this time, the first and second tongue pieces provided on the short axis and the long axis of the skirt of the mask body are welded to the mask frame, respectively.
When the mask body is pulled by the mask frame due to a difference in thermal expansion between the mask body and the mask frame, the tongue is elastically deformed outward. Thereby, the pulling force and the amount of pulling acting on the mask main body are absorbed and reduced.

The tensile force and the amount of tension acting on the mask body due to the thermal expansion of the mask frame are larger at the long axis end, which is longer from the center of the shadow mask, than at the short axis end. The second tongue piece positioned on the long axis of the mask body is easier and more easily than the first tongue piece positioned on the short axis.
Since the mask body is deformed by a larger amount, it is possible to effectively absorb the tensile force and the amount of tension acting in the major axis direction of the mask body.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A color cathode ray tube according to an embodiment of the present invention will be described below in detail with reference to the drawings. As shown in FIGS. 1 and 2, a color cathode ray tube is a vacuum envelope 7 having a panel 3 and a funnel 4.
It has. The panel 3 has a substantially rectangular effective portion 1 and a skirt portion 2 erected on the periphery of the effective portion, and a funnel 4 is joined to the skirt portion 2. The outer surface of the panel effective portion 1 is flattened, and the inner surface of the effective portion is a curved surface having a small curvature. A cylindrical neck 8 is joined to the small diameter end of the funnel 4.

In the vacuum envelope 7, the neck 3
The axis extending through the center of the panel 3 coaxially with the tube axis Z, the axis extending perpendicular to the tube axis is the horizontal axis (long axis) X, and the axis extending perpendicular to the tube axis and the horizontal axis is referred to as the axis. The vertical axis (short axis) is Y.

On the inner surface of the panel effective portion 1, a substantially rectangular phosphor screen 5 is provided. The phosphor screen 5 extends in the short-axis Y direction and is formed in a plurality of rows in parallel in the long-axis X direction. The striped black non-light-emitting layers 30 are embedded in gaps between the black non-light-emitting layers. Stripe blue extending in the short axis Y direction and regularly formed in parallel in the long axis X direction,
Three-color phosphor layers 32R, 32G, 32B emitting green and red light
And

Inside the panel 3, a phosphor screen 5 is provided.
A substantially rectangular shadow mask 6 is arranged to face the image. In the neck 8, three electron beams 9R, 9
An electron gun 10 that accelerates, converges, and emits G and 9B is provided.

In the color cathode ray tube configured as described above, the three electron beams 9R and 9R emitted from the electron gun 10 are used.
G and 9B are deflected by a magnetic field generated by a deflection yoke 11 mounted outside the funnel 4, and the phosphor screen 5 is horizontally and vertically scanned through a shadow mask 6, thereby displaying a color image.

Next, the shadow mask 6 will be described in detail. As shown in FIGS. 1 to 3, the shadow mask 6 includes a substantially rectangular mask body 15 and a substantially rectangular mask frame 18 supporting a peripheral portion of the mask body. The mask body 15 has a thickness of 0.1 to 0.3 m.
Invar material having a small coefficient of thermal expansion of about m (36% Ni-F
e alloy plate). The mask main body 15 has a rectangular mask main surface 13 facing the phosphor screen 5 and a skirt portion 14 bent around the mask main surface. The mask main surface 13 is formed of a curved surface having a small curvature corresponding to the inner surface of the panel effective portion 1.

The mask frame 18 has a side wall 16 facing the outer surface of the skirt portion 14 of the mask body 15, and an overhang 17 projecting inward from the rear end of the side wall. I have. Also, the mask frame 18
Is formed of a cold-rolled steel sheet having a large thermal expansion coefficient with a thickness of about 0.8 to 2.0 mm.

As shown in FIG. 1, the shadow mask 6 is formed by locking an elastic support 20 attached to a mask frame 18 to a stud pin 21 fixed to the skirt portion 2 of the panel 3. 3 is detachably supported inside.

As shown in FIGS. 1 to 3C, the mask main surface 13 has a substantially rectangular effective area 15a, in which a large number of slit-like electron beam passage holes 2 are provided.
3 are formed. The electron beam passage holes 23 are formed in a substantially rectangular shape, are arranged in a row in the short axis Y direction via a bridge 24, and are formed by a plurality of electron beam passage holes 23 arranged in the short axis Y direction. A plurality of through-hole rows are formed in parallel in the long axis X direction.

As shown in FIGS. 3 to 6, the skirt portion 14 of the mask body 15 has a pair of long side walls 14a extending along the long side of the mask main surface 13 and a short side of the mask main surface. It has a pair of short side walls 14b extending.
A tongue piece 26a is formed at the center of each long side wall 14a, and is located on the short axis Y. In addition, each short side wall 1
A tongue piece 26b is formed at the center of 4b, and is located on the long axis X. Similarly, a tongue piece (not shown) is formed at each corner of the skirt 14.

The tongue piece 26 provided on each long side wall 14a
a is defined by a pair of notches 25a each extending from the open edge of the skirt portion 14 along the tube axis Z direction. The pair of notches 25a extend substantially in parallel with each other and have substantially the same length. Each of the tongue pieces 26a is elastically deformable in the short axis Y direction, with the base end being a region connecting the extended ends of the pair of notches 25a.

Each tongue piece 26a is welded to the mask frame 18 at two welding points located near its free end, as indicated by the X mark. Note that another notch may be provided between the pair of notches 25a, or the lengths of the pair of notches 25a may be slightly different. In addition, the pair of notches 25a may be slightly inclined, as long as they substantially form a tongue piece.

The tongue piece 26 provided on each short side wall 14b
b is defined by a pair of notches 25b extending from the open end edge of the skirt portion 14 along the tube axis Z direction. The pair of notches 25b are formed substantially in parallel with each other and have substantially the same length. Each of the tongue pieces 26b is elastically deformable in the long axis X direction, with the base end being a region connecting the extended ends of the pair of notches 25b.

Each tongue piece 26b is welded to the mask frame 18 at two welding points located near its free end, as indicated by the X mark. Note that another notch may be provided between the pair of notches 25b, or the lengths of the pair of notches 25b may be slightly different. Further, the pair of notches 25b may be slightly inclined, as long as they substantially form a tongue piece.

When the diagonal dimension of the mask main surface 13 is RD, the width D of the skirt portion 14 along the tube axis Z direction is RD
2.5% or more. The length of the tongue piece 26a along the direction of the width D, that is, the length of each notch 25a is Ca, the width of the tongue piece 26a, that is, a pair of notches 25a.
The length between them is Wa, and the tongue piece 26b along the direction of the width D
, That is, the length of each notch 25b is Cb, the width of the tongue piece 26b is Wb, and the major axis X of the mask main surface 13 is
Assuming that the length in the direction H is the length in the short axis Y and the length in the short axis Y is V / H, the tongue pieces 26a and 26b have (Ca · Wb) <(Cb · Wa) and V <H 2, preferably (Ca · Wb) / (Cb · Wa) ≦ V / H (1) Here, V and H are V <
H is formed.

The above relationship is based on the tongue piece 2 located on the long axis X.
The ratio Ca / Wa of the length Ca and the width Wa of the tongue piece portion 26a located on the short axis Y to the ratio Cb / Wb of the length Cb of the mask main surface 13 to the ratio Cb / Wb of the length Cb of the mask main surface 13 It shows that the ratio is not more than V / H. For example, if Wa = Wb, Cb> Ca because V / H <1. Therefore, when the widths of the tongue pieces 26a and 26b are equal, the length Cb of the tongue piece 26b located on the long axis X is longer than the length Ca of the tongue piece 26a located on the short axis Y. Is done.

The length C of the tongue pieces 26a and 26b
When a and Cb are equal and Ca = Cb, Wb <Wa, and the width Wb of the tongue piece 26b located on the long axis X is smaller than the length Wa of the tongue piece 26a located on the short axis Y. It is formed.

Therefore, each tongue piece 2 provided on the long axis X
6b is formed so as to be more easily elastically deformed than the tongue pieces 26a provided on the short axis Y and to be deformable by a larger amount.

According to the color cathode ray tube configured as described above, when the shadow mask 6 is heated in the manufacturing process or when the color cathode ray tube is operated, the electron beam 9R,
When the shadow mask 6 is heated by the collision of 9G and 9B, the mask body 15 having a small coefficient of thermal expansion is pulled by the mask frame 18 having a large coefficient of thermal expansion. Since the tongue pieces 26a and 26b provided on the long axis X and the short axis Y of the skirt 14 of the mask body 15 are welded to the mask frame 18, respectively, when the mask body 15 is pulled by the mask frame, As shown in FIGS. 7A and 7B, the tongue portions 26a, 26b are elastically deformed outward. Thereby, the pulling force and the amount of pulling acting on the mask body 15 are reduced.

Here, the tensile force and the amount of tension acting on the mask body 15 due to the thermal expansion of the mask frame 18 are larger at the long axis X end where the distance from the center of the shadow mask 6 is long than at the short axis Y end. . However, according to the present embodiment, the tongue piece 26b located at the long axis X end of the mask body 15 is more easily elastically deformed than the tongue piece 26a located at the short axis Y end, and has a larger amount. Since it is formed so as to be deformable only, it is possible to effectively absorb the tensile force and the amount of tension acting on the long axis end of the mask body. Therefore, the tensile force on the long axis X acting on the mask body 15,
The amount of tension can be equal to or less than that acting on the short axis Y.

On the other hand, on the mask main surface 13 of the mask body 15, an electron beam passage hole array comprising a plurality of electron beam passage holes 23 arranged via a bridge 24 in the short axis Y direction is arranged in the long axis X direction. They are formed in parallel. Therefore, the curved surface holding strength of the mask body 15, especially the mask main surface 13, is stronger in the minor axis Y direction than in the major axis X direction, and is less likely to be deformed. Therefore, even when the tensile force acting on the short axis Y in the upward direction and the amount of tension are greater than the tensile force acting on the long axis X in the upward direction, the deformation of the mask body 15 can be prevented.

Further, the mask body 1 due to shock, vibration, etc.
5 is better when the lengths Ca and Cb of the tongue pieces 26a and 26b are shorter for the displacement of the skirt 14 in the width direction. Therefore, as described above, the tongue piece 2 on the short axis Y
6a is the length Cb of the tongue piece 26b on the major axis X.
If the length is shorter than the above, the displacement of the mask body 15 in the major axis X direction can be reduced.

Here, when the phosphor screen 5 is formed of a striped three-color phosphor layer long in the short axis Y direction, even if the landing of the electron beams 9R, 9G, 9B is shifted in the short axis Y direction. The color purity of the image does not deteriorate, and the landing margin in the short axis Y direction is large. However, the landing margin is small in the major axis X direction, and even if the landing of the electron beam is slightly shifted, the color purity is deteriorated.

Therefore, with the above-described configuration, it is possible to prevent impact or vibration or repetition of attachment / detachment of the shadow mask in the process of forming the phosphor screen.
The displacement of the mask body 15 in the long axis X direction is reduced as compared with the short axis Y direction, and a color cathode ray tube with good color purity can be configured.

It should be noted that if the above-described effects and effects satisfy the above-described expression (1), Cb> Ca and Wb <W
In any case of a, the same can be obtained.

Next, according to the present embodiment, the diagonal dimension is 76 cm.
An example in which the present invention is applied to a wide type color cathode ray tube will be described.

(Example 1) Width D30 mm by amber material
A mask body 15 having a skirt portion 14 is formed.
Tongue pieces 26a and 26b with a = 10 mm, Cb = 18 mm, and Wa = Wb = 18 mm were formed, respectively. That is, the length Cb of the tongue piece 26b located at the long axis end is formed longer than the tongue piece 26a located at the short axis end, and the width of these tongue pieces is made the same. The mask body 15 was disposed inside a mask frame 18 made of a cold-rolled steel plate, and the vicinity of the free end of each tongue piece was welded to the mask frame.

When the above-mentioned shadow mask is used, deformation of the mask body due to a difference in thermal expansion between the mask body and the mask frame is prevented, the displacement of the mask body due to shock or vibration is small, and a color cathode ray with good color purity is provided. The tube could be constructed.

(Embodiment 2) Width D 30 mm by amber material
A mask body 15 having a skirt portion 14 is formed.
Tongue pieces 26a and 26b with a = Cb = 15 mm, Wa = 18 mm, and Wb = 10 mm were formed, respectively. That is, the width Wb of the tongue piece 26b located at the long axis end is formed smaller than the width Wa of the tongue piece 26a located at the short axis end, and the lengths of these tongue pieces are made equal. And this mask body 15
Was disposed inside a mask frame 18 made of a cold-rolled steel plate, and the vicinity of the free end of each tongue piece was welded to the mask frame.

Similarly to the first embodiment, when the above-mentioned shadow mask is used, the deformation of the mask body due to the difference in thermal expansion between the mask body and the mask frame is prevented, and the displacement of the mask body due to shock or vibration is small. A color cathode ray tube with good color purity could be constructed.

In the above-described embodiment, each tongue piece formed on the skirt portion of the mask body is formed by forming a notch on the skirt portion. However, as shown in FIG. Each tongue piece 26 may be configured as a protrusion extending from the open edge of the skirt 14. Also in this case, by setting the length and width of the tongue piece on the short axis and the long axis of the mask body so as to satisfy the above-described formula (1), the same effect as in the above embodiment can be obtained. Can be

Further, in the above-described embodiment, the wide type color cathode ray tube in which the ratio V / H between the short axis and the long axis of the phosphor screen is 9/16 has been described.
The same effect can be obtained even when applied to a normal color cathode ray tube having / H of 3/4.

[0052]

As described in detail above, according to the present invention, it is possible to provide a color cathode ray tube in which the deterioration of color purity due to the deformation and displacement of the shadow mask is reduced and the image quality is improved.

[Brief description of the drawings]

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

FIG. 2 is a perspective view schematically showing a phosphor screen, a shadow mask, and an electron gun in the color cathode ray tube.

FIG. 3 is a plan view of the shadow mask, taken along line IIIB-I.
FIG. 3C is a cross-sectional view along IIB and a cross-sectional view along line IIIC-IIIC.

FIG. 4 is a perspective view showing a part of a short-axis end of the shadow mask cut away.

FIG. 5 is a perspective view showing a major axis end of the shadow mask, partially cut away.

FIG. 6 is a front view showing a tongue piece of the shadow mask.

FIG. 7 is a sectional view schematically showing a positional relationship between a tongue piece of the shadow mask and a mask frame.

FIG. 8 is a perspective view showing a modification of the tongue piece of the shadow mask.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Panel 5 ... Phosphor screen 6 ... Shadow mask 10 ... Electron gun 11 ... Deflection yoke 13 ... Mask main surface 14 ... Skirt part 15 ... Mask body 16 ... Side wall 18 ... Mask frame 25a, 25b ... Notch 26a, 26b ... Tongue piece

Continuation of the front page (72) Inventor Yoshiaki Ito 1-9-2, Hara-cho, Fukaya-shi, Saitama F-term in Toshiba Fukaya Factory Co., Ltd. 5C031 EE04 EE11

Claims (8)

[Claims] A panel having a substantially rectangular effective portion and having a tube axis, a long axis perpendicular to the tube axis, and a short axis extending perpendicular to the tube axis and the long axis. A phosphor screen having a plurality of phosphor layers formed on an inner surface of the effective portion and each extending along a direction substantially parallel to the short axis; and a phosphor screen facing the phosphor screen. A shadow mask provided in the envelope; and an electron gun provided in the envelope and irradiating the phosphor screen with an electron beam through the shadow mask. A substantially rectangular mask main surface facing the phosphor screen and having a large number of electron beam passage holes formed thereon, a skirt portion bent around the mask main surface, and the long axis and the short axis Long axis and short axis corresponding to A substantially rectangular mask body having: a substantially rectangular mask frame attached to the skirt portion and located outside the skirt portion; the mask frame having a larger coefficient of thermal expansion than the mask body. A skirt portion of the mask body is located on the short axis and extends along the tube axis direction, and a first tongue piece portion is located on the long axis and the tube is located on the long axis. A second tongue piece extending along the axial direction, wherein the first and second tongue pieces each have a free end and are fixed to the mask frame; The length of the first tongue along the first tongue is Ca, the width of the first tongue is Wa, the length of the second tongue along the tube axis direction is Cb, and the width of the second tongue is Wb. When the length in the major axis direction of the mask main surface is H and the length in the minor axis direction is V, the mask body Is a color cathode ray tube formed so as to satisfy the following relationships: (Ca · Wb) <(Cb · Wa) and V <H. 2. The mask body according to claim 1, wherein (Ca.Wb) / (C
2. The color cathode ray tube according to claim 1, wherein the color cathode ray tube is formed so as to satisfy a relationship of b · Wa) ≦ V / H. 3. The color cathode ray tube according to claim 1, wherein the first and second tongue pieces have a relationship of Ca = Cb and Wa> Wb. 4. The color cathode ray tube according to claim 1, wherein the first and second tongue pieces have a relation of Wa = Wb and Ca <Cb. 5. A pair of first notches extending from a free edge of the skirt toward the main surface of the mask along the tube axis direction and defining the first tongue piece. A pair of second notches extending from a free edge of the skirt portion toward the main surface of the mask along the tube axis direction and defining the second tongue piece portion. Item 2. A color cathode ray tube according to item 1. 6. The skirt portion includes a plurality of projections extending from a free edge of the skirt portion along the tube axis direction and forming the first tongue piece and the second tongue piece. The color cathode ray tube according to claim 1, wherein: 7. The electron beam passing holes are formed in a substantially rectangular shape, are arranged in a row in the short axis direction via a bridge, and are formed of a plurality of electron beam passing holes arranged in the short axis direction. 7. The color cathode ray tube according to claim 1, wherein a plurality of beam passage hole arrays are formed in parallel in the long axis direction. 8. A panel having a substantially rectangular effective portion and having a tube axis, a long axis perpendicular to the tube axis, and a short axis extending perpendicular to the tube axis and the long axis. A phosphor screen having a plurality of phosphor layers formed on an inner surface of the effective portion and each extending along a direction substantially parallel to the short axis; and a phosphor screen facing the phosphor screen. A shadow mask provided in the envelope; and an electron gun provided in the envelope and irradiating the phosphor screen with an electron beam through the shadow mask. A substantially rectangular mask main surface facing the phosphor screen and having a large number of electron beam passage holes, a skirt portion bent around the mask main surface, and the long axis and the short axis Long axis and short axis corresponding to And a substantially rectangular mask frame attached to the skirt portion and located outside the skirt portion, the mask frame having a larger coefficient of thermal expansion than the mask body. The skirt portion of the mask body is located on the short axis, extends along the tube axis direction, and is elastically deformable along the short axis direction. A first tongue piece that is located on the long axis and extends along the tube axis direction and is elastically deformable along the long axis direction; Each of the pieces has a free end and is fixed to the mask frame. The second tongue is easier to elastically deform than the first tongue, and is larger than the first tongue. It is characterized by being deformable by the amount Color cathode ray tube.