JP2002216660A - Color distinction mechanism, its manufacturing method and cathode ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color distinction mechanism to suppress generation of a welding splash during the period of welding the color distinction mask to the frame. SOLUTION: The pre-application welding surface 13 is to be inclined to keep the outside lower than inside in a horizontal direction meeting at right- angled with the longitudinal direction to get complete contacts without any gap throughout between the rear surface of the said color distinction mask 2 and the welding surface 13 equipped with A member comprising the frame 3 when transformed elastically by applying to the frame 3 to weld the color distinction mask 2 to the frame 3. The inclination angle of the welding surface 13 becomes bigger toward the center and smaller toward the end in the longitudinal direction of the welding surface 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of mounting a color selection mask on a frame by welding a color selection mask having a plurality of through holes such as slits formed on a thin metal plate to a welding surface of the frame. By attaching a color selection mask to the elastically deformed frame,
The present invention relates to a color selection mechanism in which a color selection mask is stretched on the frame with a predetermined tension applied thereto, a method of manufacturing the color selection mechanism, and a cathode ray tube having the color selection mechanism.

More specifically, when the color selection mask is brought into contact with the welding surface of the frame before being elastically deformed at an angle with respect to the color selection mask and the frame is elastically deformed, when the color selection mask is brought into contact with the welding surface, the color selection is performed. This technology prevents the opening of a gap between the mask and the spatter during welding.

[0003]

2. Description of the Related Art A cathode ray tube has a dot-type or stripe-like red (R), green (G), and blue (B) phosphor layer on the inner surface of a panel portion provided in front of the cathode ray tube. The image is displayed by irradiating an electron beam with an electron gun. At that time, a color selection mechanism is used as a means for accurately irradiating an electron beam that illuminates the three phosphors of red (R), green (G), and blue (B) onto the predetermined phosphors.

The color selection mechanism includes a color selection mask for selectively transmitting an electron beam, a frame for supporting the color selection mask, and the like.

FIG. 6 is a perspective view showing a color selection mechanism.
(A) shows the frame before the color selection mask is attached, and (b) of FIG. 6 shows a state where the color selection mask is attached to the frame. Color selection mask 2 constituting color selection mechanism 1
For example, as shown in FIG. 6 (b), this is called a FAG (Flat Aperture Grill) in which a plurality of longitudinal slits 2a are provided in a substantially rectangular thin metal plate. The space between the slits 2a is an elongated tape shape, and this tape-shaped portion is called an AG tape.

A frame 3 for supporting the color selection mask 2
As shown in FIG. 6 (a), an A member 4 having an L-shaped cross section and a B member 5 having a U-shape and having the A members 4 attached to both ends thereof, respectively. The A member 4 and the B member 5 are each formed of, for example, a stainless steel material, and are mutually integrated by welding.

As shown in FIG. 6 (b), both sides of the color selection mask 2 in the short direction are supported by the A members 4, respectively. The color selection mask 2 of the A member 4 is attached to the A member 4 by welding.
FIG. 6 (a) shows the front side opposite to the back side of both sides in the short side direction of FIG.
As shown in FIG. 2, the color selection mask 2 has a welding surface 4a extending along the longitudinal direction.

[0008] In order to stretch the color selection mask 2 between the A members 4 of the frame 3 while applying a predetermined tension to the color selection mask 2, the frame 3 is pressed and elastically deformed. By attaching the color selection mask 2 to the welding surface 4a of the A member 4 by welding and then releasing the pressure applied to the frame 3, a predetermined tension is applied to the color selection mask 2 by the repulsive force of the frame 3. It is.

FIG. 7 is an explanatory view showing such a color selection mask stretching step. First, the frame 3 before the color selection mask 2 as shown in FIG.
As shown in (a), it is set on a fixed table (not shown) of the welding machine.

Next, as shown in FIG. 7B, the A member 4 of the frame 3 is moved outward by the vise 6 of the welding machine in a direction orthogonal to the longitudinal direction of the A member 4 as shown by an arrow a. And pressurize. By this pressurization, the A member 4 and the B member 5 of the frame 3 are elastically deformed, and the deformation raises the side of the A member 4 to raise the side surfaces of the welding surfaces 4a of the two A members 4 in the longitudinal direction. And the horizontal interval perpendicular to the horizontal direction becomes smaller.

Next, the color selection mask 2 is set on the upper side of the frame 3 which is held in a state of being elastically deformed by pressing as described above. That is, as shown in FIG. 7C, the color selection mask 2 is placed on the base 7 of the welding machine, and the color selection mask 2 is placed between the clamper 8 and the base 7 by the clamper 8.
The color selection mask 2 is pulled in the direction in which the slit 2a shown in FIG. 6B extends by pulling the color selection mask 2 in the direction of the arrow b to eliminate the slack of the AG tape.

Next, as shown in FIG. 7 (d), the frame 3 held in the pressurized state is raised, and the welding surface 4a of the A member 4 is abutted against the back surface of the color selection mask. And a roller electrode 9 provided with a plurality of electrodes on the circumference.
Is brought into contact with the surface of the portion of the color selection mask 2 which is in contact with the welding surface 4a, and is rolled in accordance with the position of the welding surface 4a.
Is seam-welded to the welding surface 4a. When the welding is completed, the holding of the color selection mask 2 by the clamper 8 is released,
The pressurization by the vise 6 is released.

As a result, the color selection mechanism 1 as shown in FIG. 6B is assembled. As described above, when the color selection mask 2 is welded, the frame 3 is moved in the longitudinal direction of the A member 4. It is held in a state where it is pressed from the outside in a direction perpendicular to the direction as shown by an arrow c in FIG. After the welding of the color selection mask 2 is completed, by releasing the pressurization, a repulsive force shown by an arrow d in FIG. 6B is generated in the frame 3, whereby the repulsive force is reduced. , A predetermined tension is applied to the color selection mask 2.

[0014]

FIG. 8 is an explanatory view showing a conventional problem, and FIGS. 8 (a) to 8 (c) are sectional views of the A member 4 cut in a direction perpendicular to the longitudinal direction.

FIG. 8A shows the state of the A member 4 of the frame 3 before being pressed by the vise 6. The A member 4 having an L-shaped cross section has an L-shaped side before being pressed by the vise 6. The part is slightly inclined. The angle of this inclination is defined as θ1. And the welding surface 4a is horizontal.

FIG. 8B shows the state of the A member 4 when pressed by the vise 6, and the L-shaped side of the A member 4 when pressed by the vise 6 is substantially vertical. Thus, the welding surface 4a has an inclination of an angle θ1 with respect to the horizontal plane in a direction orthogonal to the longitudinal direction.

As shown in FIG. 8C, when the welding surface 4a is inclined by an angle θ1 with respect to a horizontal plane in a direction perpendicular to the longitudinal direction by the pressurization by the vice 6, as shown in FIG. The welding surface 4a is abutted against the back surface of the color selection mask 2 and welding is performed by the roller electrode 9. However, since the welding surface 4a is inclined, there is a gap between the welding surface 4a and the back surface of the color selection mask 2. Welding is performed with the gap open.

Thus, the welding surface 4a and the color selection mask 2
When welding is performed in a state where there is a gap between the back surface and the back surface, there is a problem that the contact of the color selection mask 2 is not stable, and so-called welding splash in which the color selection mask 2 melts and scatters easily occurs.

When the metal powder welding splash adheres to the color selection mask 2 and the color selection mask 2 is incorporated in the cathode ray tube, the metal powder attached to the color selection mask 2 falls into the cathode ray tube. When it adheres to an electron gun, it emits unnecessary electrons from the metal powder and causes a so-called breakdown voltage failure that causes a discharge. Also, the welding splash forms an effective surface for displaying an image of the color selection mask 2. When adhered, the image may be deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and when a color selection mask is welded to a frame, a color selection mechanism capable of suppressing the occurrence of welding splash and a color selection mechanism of this color selection mechanism are provided. It is an object of the present invention to provide a manufacturing method and a cathode ray tube provided with this color selection mechanism.

[0021]

According to the present invention, there is provided a color selection mechanism comprising: a color selection mask formed of a rectangular metal thin plate; and a back surface of two opposite sides of the color selection mask.
A frame provided with first and second welding surfaces extending along the sides of the color selection mask;
And color selection of the frame elastically deformed in a direction in which the interval between the second welding surfaces is reduced, by welding the first welding surface and the second welding surface to the back surface of the color selection mask. In the mechanism, when the color selection mask is brought into contact with each of the first welding surface and the second welding surface, the entire surface of each of the first and second welding surfaces and the back surface of the color selection mask are fitted without any gap. In this manner, the first and second welding surfaces of the frame before being elastically deformed are inclined so that the outside is lower than the inside in a horizontal direction orthogonal to the longitudinal direction of each welding surface. .

Further, the method for manufacturing a color selection mechanism according to the present invention is characterized in that a color selection mask made of a rectangular metal sheet and a back surface of two opposite sides of the color selection mask are respectively opposed to each other;
A frame provided with first and second welding surfaces extending along the sides of the color selection mask, wherein the frame is pressurized to reduce the distance between the first and second welding surfaces. A color separation mask in which the back surface of the color selection mask is welded to the first and second welding surfaces of the frame in which the force returning in the direction of opening the gap between the welding surfaces is stored by elastically deforming the welding surfaces. In the method for manufacturing a mechanism, when the color selection mask is brought into contact with each of the first welding surface and the second welding surface, the entire surface of each of the first and second welding surfaces and the back surface of the color selection mask are The first and second welding surfaces of the frame before the elastic deformation are inclined so that the outside is lower than the inside in a horizontal direction orthogonal to the longitudinal direction of each welding surface so that they fit together without a gap. After the frame is pressurized to bring the first and second welding surfaces into a horizontal state with respect to the color selection mask, the welding is performed by abutting each of the welding surfaces against the back surface of the color selection mask, Is released.

A cathode ray tube according to the present invention is provided with the above-described color selection mechanism. In the color selection mechanism, the frame on which the color selection mask is attached is pressurized so as to deform in a direction in which the distance between the welding surfaces decreases when welding the color selection mask. It changes before and during pressurization during welding. According to the present invention, when the color selection mask is brought into contact with the welding surface in a state of being pressed against the frame, the welding surface of the frame before pressing is pressed so that the entire surface of the welding surface and the back surface of the color selection mask fit together without a gap. , The welding surface and the color selection mask are brought together without any gap at the time of welding. Thereby, the occurrence of welding splash can be suppressed. In addition, by incorporating the color selection mechanism in which the generation of the welding splash is suppressed into the cathode ray tube, it is possible to prevent the screen from deteriorating.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the color selection mechanism of the present invention will be described below with reference to the drawings. FIG. 1 is a partially cutaway perspective view showing a cathode ray tube to which the color selection mechanism of the present embodiment is applied. The cathode ray tube 10 has a panel portion 11 on the front surface, and has, for example, striped red (R), green (G), and blue (B) phosphor layers (not shown) on the inner surface of the panel portion 11. The color selection mechanism 1 is mounted inside the panel section 11 of the cathode ray tube 10.

The color selection mechanism 1 comprises a color selection mask 2 for selectively transmitting an electron beam, a frame 3 for supporting the color selection mask 2, and the like. It is attached inside the cathode ray tube 10 so as to face each other.

The color selection mask 2 selectively transmits an electron beam and emits red (R),
The electron beams corresponding to green (G) and blue (B) are respectively transmitted to red (R), green (G),
In order to reach the respective blue (B) phosphors, through holes or vertical slits 2a as shown in FIG. 1 are provided.

The color selection mask 2 has both ends in the transverse direction in which the slits 2a extend, and is attached to the A members 4 constituting the frame 3 by welding. The structure is supported by the B member 5.

Next, the details of the color selection mechanism 1 will be described.
FIG. 2 is an explanatory view showing the color selection mechanism of the present embodiment.
(A) is a partial cutaway front view of the color selection mechanism in which the color selection mask is broken, (b) is a bottom view of the color selection mechanism, and (c) of FIG.
FIG. 3 is a side view of a color selection mechanism.

As shown in FIG. 2A, for example, the color selection mask 2 is a FAG (Flat Apert) formed by arranging a plurality of vertical slits on a substantially rectangular thin metal plate.
ure Grill).

A frame 3 for supporting the color selection mask 2
Is composed of an A member 4 having an L-shaped cross section and B members 5 each having a U-shape and having the A members 4 attached to both ends thereof. The A member 4 and the B member 5 are each formed of a stainless material such as SUS410, for example.
They are integrated by welding.

The color selection mask 2 is supported by the A members 4 on both sides in the short direction. Since the color selection mask 2 is attached to the A member 4 by welding, the color selection mask 2 is provided along the longitudinal direction of the color selection mask 2 on the front of the A member 4 opposite to the back surfaces of both sides in the lateral direction of the color selection mask 2. And has a welding surface 13 extending therefrom.

Then, in order to stretch the color selection mask 2 between the A members 4 of the frame 3 while applying a predetermined tension to the color selection mask 2, the frame 3 is pressed and elastically deformed. By attaching the color selection mask 2 to the welding surface 13 of the A member 4 by welding, and then releasing the pressure applied to the frame 3, a predetermined tension is applied to the color selection mask 2 by the repulsive force of the frame 3. It is.

In addition, in addition to the above-described structure, the color selection mechanism 1 is incorporated in the cathode ray tube 10 as shown in FIG. 1, so that the color selection mechanism 1 is supported by the cathode ray tube 10. Although springs and vibration-proof wires for suppressing vibration of the color selection mask 2 are provided, they are not shown in FIG.

FIG. 3 is a side view of a main part showing details of the color selection mechanism of the present embodiment. The welding surface 13 of the A member 4 before pressurization shown by the solid line in FIG. 3 is inclined so that the outside is lower than the inside in a horizontal direction orthogonal to the longitudinal direction of the welding surface 13.

As described with reference to FIG. 7, when the color selection mask 2 is welded to the frame 3, the A member 4 is
Is applied from the outside in a direction orthogonal to the longitudinal direction. Due to this pressurization, the A member 4 and the B member 5 of the frame 3 are elastically deformed, and the side of the A member 4 is raised by the deformation.

When the side of the A member 4 is raised, the angle of the welding surface 13 in the horizontal direction orthogonal to the longitudinal direction of the welding member 13 changes with respect to the horizontal plane, that is, the color selection mask 2. When the welding surface 13 of the member 4 is inclined so that the outside is lower than the inside in the horizontal direction orthogonal to the longitudinal direction, as the side of the A member 4 rises, the welding surface 13 The angle in the orthogonal horizontal direction decreases and approaches horizontal.

Thus, if the welding surface 13 is provided with a proper inclination, the side of the A member 4 is raised by pressurization, and the color selection mask 2 shown by the broken line in FIG. 3 is welded. Then, the welding surface 13 can be made horizontal with respect to the color selection mask 2.

Here, since both ends of the A member 4 are supported by the B member 5, the decrease in the angle of the welding surface 13 due to the rise of the side of the A member 4 is caused by the center of the welding surface 13 in the longitudinal direction. The closer it is, the greater the amount of rise due to the less restraint by the B member and the greater the amount of rise.
Since it is supported by the member 5, deformation due to pressurization is small and the amount of rise is small, so that the angle decreases less toward the end.

For this reason, when the side portion of the A member 4 is raised by pressurization, the inclination of the welding surface 13 is set to be horizontal with respect to the color selection mask 2 over the entire surface of the welding surface 13. In the longitudinal direction, the center and the end have different angles.

That is, when the longitudinal direction of the welding surface 13 is the x-axis, the angle θ at an arbitrary position in the longitudinal direction of the welding surface 13 (when the color selection mask 2 is a horizontal plane, the angle with respect to this horizontal plane) is: It can be defined as a function of the distance x from the center of the welding surface 13 in the longitudinal direction. For example, the angle θ can be approximated by a quadratic function polynomial including a constant term.

The following expression (1) is an example of a definition expression of the angle θ (= y) when the size of the cathode ray tube 10 is 17 inches as shown in FIG. y = (− 7 × 10 ⁻⁵ ) x ² + 0.0004x + 3.00086 (1)

FIG. 4 is a graph showing the change in the angle of the welding surface. FIG. 4 is a graph showing the calculation result of the equation (1). The horizontal axis represents the distance x from the center of the welding surface 13 in the longitudinal direction.
(Mm), and the vertical axis represents the angle y (°) of the welding surface 13.

As shown in FIG. 4, when equation (1) is applied, the angle takes the largest value at the center in the longitudinal direction of the welding surface 13, and decreases toward the end, and the angle decreases. The decreasing rate increases toward the end. Therefore,
The welding surface 13 becomes an inclined surface having the largest angle at the center in the longitudinal direction, and becomes a gentle inclined surface toward the end.

The welding surface 13 is formed in advance by cutting or the like, for example, as an inclined surface having an angle determined by equation (1), in a shape shown by a solid line in FIG. In FIG. 3, the angle θ (P1) indicates the angle of inclination at the longitudinal end of the welding surface 13, and the angle θ (P2) indicates
It indicates the angle of inclination at the center in the longitudinal direction of the welding surface 13, where θ (P1) <θ (P2).

Next, a process of welding the color selection mask 2 to the frame 3 in which the welding surface 13 has an angle will be described with reference to FIG. In the following description, the conventional welding surface 4a in FIG. 7 is replaced with the welding surface 13 of the present embodiment.

First, as shown by the solid line in FIG. 3, the welding surface 13 is previously processed as an inclined surface having a predetermined angle, and the frame 3 before the color selection mask 2 is attached.
Is set on a fixed table (not shown) of the welding machine as shown in FIG.

Next, as shown in FIG. 7B, the A member 4 of the frame 3 is moved outward by the vise 6 of the welding machine in the direction orthogonal to the longitudinal direction of the A member 4 as shown by an arrow a. And pressurize. Due to this pressurization, the A member 4 and the B member 5 are elastically deformed in the frame 3, and the side portions of the A member 4 are raised by the deformation, and the welding surface 13 of each of the two A members 4 is moved in the longitudinal direction. And the horizontal interval perpendicular to the horizontal direction becomes smaller.

In this pressurized state, the A member 4 is
In the state shown by the broken line. That is, since the welding surface 13 of the A member 4 before pressurization is an inclined surface in which the outside is lower than the inside in a horizontal direction orthogonal to the longitudinal direction, as the side of the A member 4 rises by pressurization, The angle of the welding surface 13 in the horizontal direction orthogonal to the longitudinal direction decreases. The decrease in the angle of the welding surface 13 due to the rise of the side portion of the A member 4 is greater near the center of the welding surface 13 in the longitudinal direction, and the angle decreases less toward the end. The angle of the welding surface 13 is set at the center of the longitudinal direction of the A member 4 and the end of the A member 4 because the angle is the largest at the center in the longitudinal direction and the angle is gentler toward the end. Thus, the entire surface of the welding surface 13 is horizontal with respect to the color selection mask 2.

Next, the color selection mask 2 is set on the upper side of the frame 3 held in a pressurized state as described above. That is, as shown in FIG. 7 (c), the color selection mask 2 is placed on the base 7 of the welding machine, the color selection mask 2 is sandwiched between the clamper 8 and the base 7 by the clamper 8, and the color selection is performed. The mask 2 is pulled in the direction in which the slit 2a extends, and A
Eliminate the slack of G tape.

Next, as shown in FIG. 7D, the frame 3 held in the pressurized state is raised, and the welding surface 13 of the A member 4 is butted against the back surface of the color selection mask 2. FIG. 5 is an explanatory diagram showing the operation of this embodiment.
Is the welding surface 1 of the frame 3 held in a pressurized state
A member 4 with the color selection mask 2 abutting against 3
FIG. 3 is a cross-sectional view taken along a direction perpendicular to the longitudinal direction.

The frame 3 held in a pressurized state
Since the welding surface 13 is horizontal to the color selection mask 2, when the welding surface 13 is abutted against the color selection mask 2, a gap is opened between the welding surface 13 and the color selection mask 2. Absent.

With no gap between the welding surface 13 and the color selection mask 2, the roller electrode 9 is brought into contact with the surface of the portion of the color selection mask 2 that is in contact with the welding surface 13a. The color selection mask 2 is rolled in accordance with the position of the welding surface 13, and the color selection mask 2 is seam-welded to the welding surface 13 of the A member 4 of the frame 3.

Thus, the welding surface 13 and the color selection mask 2
If welding is performed in a state where there is no gap between the color selection mask 2 and the contact point, the generation of splash is suppressed.
Splashes can be prevented from adhering.

Thus, the color selection mechanism 1 of the present invention is shown in FIG.
As shown in (1), by incorporating into the cathode ray tube 10, a color selection mechanism to which a splash is attached can be prevented from causing a pressure resistance failure, and the screen can be prevented from deteriorating.

When the welding is completed, the holding of the color selection mask 2 by the clamper 8 is released, and the pressurization by the vise 6 is released. Thereby, the color selection mechanism 1 as shown in FIG. 2 is assembled. As described above, when the color selection mask 2 is welded, the frame 3 is moved from the outside in a direction orthogonal to the longitudinal direction of the A member 4. It is held in a pressurized state. After the welding of the color selection mask 2 is completed, the pressurization is released, so that a repulsive force indicated by an arrow c in FIG. 2 is generated in the frame 3, and the repulsive force acts on the color selection mask 2. Thus, a predetermined tension is applied to the color selection mask 2.

In this embodiment, the angle of the welding surface 13 is defined by the equation (1). However, the present invention is not limited to this, and the material, size, and structure of the frame 3 are different. The definition formula of the angle is different due to the difference in the pressing force caused by the above.

The angle of the welding surface 13 includes a constant term 2
Although approximation was made by the polynomial of the following function, the angle at an arbitrary point in the longitudinal direction of the welding surface 13 may be obtained by a quadratic function, and between the points may be obtained by approximation by a linear function. In FIG. 4, a graph indicated by a broken line indicates an arbitrary point in the longitudinal direction of the welding surface 13, for example, both ends P1, a center P2, and a certain point P3 between the end and the center are obtained by Expression (1). The interval is approximated by a linear function.

[0058]

As described above, according to the present invention, when the color selection mask is brought into contact with the welding surface of the frame supporting the color selection mask, the entire surface of the welding surface and the back surface of the color selection mask have no gap. To fit, the welding surface before the frame is elastically deformed by pressing is inclined so that the outside is lower than the inside in the horizontal direction perpendicular to the longitudinal direction, so the color selection mask and the welding surface are abutted. When performing welding, welding can be performed without any gap between the color selection mask and the welding surface. As a result, splash during welding can be prevented, and by suppressing the occurrence of splash, splash is prevented from adhering to the color selection mask. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing a cathode ray tube.

FIG. 2 is an explanatory diagram showing a color selection mechanism of the embodiment.

FIG. 3 is a main part side view showing details of a color selection mechanism of the embodiment.

FIG. 4 is a graph showing a change in the angle of a welding surface.

FIG. 5 is an explanatory diagram showing the operation of the present embodiment.

FIG. 6 is a perspective view showing a color selection mechanism.

FIG. 7 is an explanatory view showing a stretching step of a color selection mask.

FIG. 8 is an explanatory diagram showing a conventional problem.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Color selection mechanism, 2 ... Color selection mask, 3 ...
Frame, 4 ... A member, 5 ... B member, 13
... Weld surfaces

Claims (5)

[Claims] 1. A color selection mask made of a rectangular metal thin plate, and first and second color selection masks extending along the sides of the color selection mask, each of which opposes two opposite back surfaces of the color selection mask. A frame provided with a welding surface, wherein the first welding surface and the second welding surface of the frame in a state of being elastically deformed in a direction in which a distance between the first and second welding surfaces is reduced. In a color selection mechanism formed by welding against the back surface of a color selection mask, the first and second weldings are performed when the color selection mask is brought into contact with each of the first welding surface and the second welding surface. The first and second welding surfaces of the frame in a state before the elastic deformation are performed in a horizontal direction orthogonal to the longitudinal direction of each welding surface so that the entire surface of each surface and the back surface of the color selection mask fit together without a gap. Inside Color selecting, characterized in that outside tilted to be lower. 2. The color selection mechanism according to claim 1, wherein an inclination of each of the welding surfaces changes continuously along a longitudinal direction of each of the welding surfaces. 3. The inclination of each of the welding surfaces is such that the angle becomes steeper as it approaches the center in the longitudinal direction of the welding surface, and decreases in a quadratic function toward the end in the longitudinal direction. 3. The color selection mechanism according to claim 2, wherein 4. A color selection mask made of a rectangular metal thin plate, and first and second color selection masks respectively opposed to two opposite back sides of the color selection mask and extending along the sides of the color selection mask. And a frame on which a welding surface is provided. The frame is pressurized and elastically deformed in a direction in which the distance between the first and second welding surfaces is reduced, thereby returning to a direction in which the distance between the welding surfaces is increased. A method for manufacturing a color selection mechanism for welding a back surface of the color selection mask to the first and second welding surfaces of the frame in which force is stored, wherein the first welding surface and the second welding surface are provided. When the color selection mask is abutted against each of the frames, the frame before being elastically deformed so that the entire surfaces of the first and second welding surfaces and the back surface of the color selection mask are fitted without any gap. First and second welding surfaces are inclined so that the outside is lower than the inside in a horizontal direction orthogonal to the longitudinal direction of each welding surface, and the first and second welding surfaces are pressed by pressing the frame. A horizontal state with respect to the color selection mask, then welding each of the welding surfaces against the back surface of the color selection mask to perform welding and releasing the pressure applied to the frame. . 5. A color selection mask made of a rectangular metal thin plate and selectively transmitting an electron beam, and opposite to the back surfaces of two opposite sides of the color selection mask, respectively, along the side of the color selection mask. A frame provided with extending first and second welding surfaces, wherein the first and second welding surfaces are provided.
A color selection mechanism in which the first welding surface and the second welding surface of the frame elastically deformed in a direction in which the distance between the welding surfaces is narrowed are welded by abutting the first welding surface and the second welding surface against the back surface of the color selection mask. In the cathode ray tube, when the color selection mask is brought into contact with each of the first welding surface and the second welding surface with the color selection mask, a color of the first and second welding surfaces is adjusted. The first and second welded surfaces of the frame in the state before the elastic deformation are lower than the inner side in the horizontal direction orthogonal to the longitudinal direction of each welded surface so that the back surfaces of the selection masks fit together without a gap. A cathode ray tube characterized by being inclined as described above.