JP2003059396A - Manufacturing device of cathode-ray tube, cathode-ray tube and method of its manufacturing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing device of a cathode-ray tube capable of installing a shadow mask on a support in an accurate flat state without recess or projection. SOLUTION: This manufacturing device of the cathode-ray tube sticks and assembles the shadow mask 1 on the support 5 in a tensioned state, and has first tensioning parts 10 for applying tensile force in the oblique outward direction to the side edge of the shadow mask 1 in four-corners of the shadow mask 1, and has tension tools 11 for constituting second tensioning means for applying tensile force in the oblique direction of the shadow mask 1 in two stages by using the first tensioning parts 10, and applying the tensile force in the vertical direction to the long side edge of the shadow mask 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube manufacturing apparatus and a cathode ray tube used for displaying an image on a television receiver and the like, and a method for manufacturing the same.

[0002]

2. Description of the Related Art In a cathode ray tube used in a television receiver, an image is drawn by accurately irradiating each bright spot with an electron beam that has passed through minute through holes formed in a shadow mask. Therefore, the shadow mask must be mounted accurately so that it is not distorted or misaligned. In recent years, flat-screen televisions or flat televisions having flat image display surfaces have become mainstream as television receivers, and accordingly, almost flat shadow masks have been used. In order to flatly support the shadow mask, the shadow mask is fixed to the rectangular support body by welding or the like in a tensioned state. In order to fix the four corners of the shadow mask, it is said that fixing only the opposing long sides to the support is more suitable for supporting the shadow mask in a planar shape.

FIG. 7 shows an example of a conventional method for fixing a shadow mask to a support. That is, the shadow mask 5
1 has a perforated region 53 in which a fine through hole 52 is formed in the central portion thereof, and a peripheral region 54 in which a positioning hole 59 is formed outside thereof. The support 55 is constructed by assembling a pair of long side supports 56 and a pair of short side supports 57 in a cross beam shape. The upper end surface 58 of the long-side support member 56 is slightly curved along the long-side direction of the long-side support member 56, and the central portion is high and the height is low toward both sides. The shadow mask 51 has a positioning hole 5
9 is fixed to the upper end surface 58 of the long side support 56 by welding or the like in a state where the relative positional relationship with the support 55 is accurately maintained.

As a method of accurately fixing the shadow mask on the support without distortion such as wrinkles, for example, an inward pressure is applied to the long side support 56 of the support 55 and the shadow mask 51 is applied. The support 55 and the positioning hole 59
Position with. Next, shadow mask 51-4
The tension means engaged in the corner is sequentially moved in the short side support direction and the long side support direction to give tension to the shadow mask 51, and in that state the tension means moves downward (support direction), The support 55 and the shadow mask 51 are brought into close contact with each other, and downward tension (pulling force) is applied to the shadow mask 51. In this state, the shadow mask 51 and the upper end surface 58 of the support body 55 are welded and fixed, and then the pressure applied to the long side support body 56 of the shadow mask 51 is released. This method prevents deformation such as twisting and wrinkling (for example, Japanese Patent Publication No. 6-87394).

Further, as shown in FIG. 8, the pulling means 60 engaged with the four corners of the shadow mask 51 are directed outward in the direction indicated by P ₁ , that is, in the direction oblique to the side of the shadow mask 51. A method of applying a pre-tension has been proposed (for example, Japanese Patent Laid-Open No. 2001-185026). In this case, the angle in the diagonal direction is 15 with respect to the long side direction.
The main pulling means 61 applies the asserting force P _{2 in a} direction perpendicular to the long side direction by setting the angle to be about 45 degrees. By setting the tension direction and its magnitude to a predetermined magnitude in the pre-tension stage, distortion such as wrinkles that occurs in the shadow mask 51 when the main tension force is applied is suppressed.

[0006]

When the shadow mask is fixed to the support, the opposing long sides of the shadow mask are pulled outward to bring them into a tensioned state so that they are in contact with the support and fixed by welding. . However, even if the shadow mask is held in a tension state with a sufficient tensile force, if the heat treatment is applied to the shadow mask fixed to the support, there is a problem that the flatness of the shadow mask is impaired. That is, there is a problem that streaky unevenness extending in a direction perpendicular to the long side is generated in the shadow mask after the heat treatment.

In view of the above, the present invention allows the shadow mask to be attached to the support in a precise flat state without unevenness even after the heat treatment process is applied to the shadow mask assembly.
Provided are a cathode ray tube manufacturing apparatus, a cathode ray tube, and a method for manufacturing the same.

[0008]

The apparatus for manufacturing a cathode ray tube according to the present invention has a sheet-shaped shadow mask having four regions having a large number of through-holes, which is provided at four corners of the shadow mask and is obliquely outside the side of the shadow mask. A first stretching means for applying a tensile force in a direction is provided, and the first stretching means is configured to apply the tensile force in two stages having different tensile forces.

Further, the cathode ray manufacturing apparatus of the present invention is provided with a second elongating means for applying a tensile force in a direction perpendicular to the long side of the shadow mask.

Further, the cathode ray tube of the present invention is a cathode ray tube having a sheet-shaped shadow mask having a region having a large number of through holes on a support body having a substantially rectangular frame shape,
A pattern is provided in at least one corner of this sheet-shaped shadow mask.

Further, the method of manufacturing a cathode ray tube according to the present invention is a method of sticking a sheet-shaped shadow mask having a region having a large number of through holes on a support having a substantially rectangular frame shape, While positioning the shadow mask with respect to the support, a step (a) of applying a predetermined tensile force to the four corners of the shadow mask in a diagonally outward direction with respect to the side of the shadow mask, and after the step (a) Then, a step (b) of applying a tensile force larger than the predetermined tensile force to the shadow mask is provided.

[0012]

(First Embodiment) FIG. 1 is a plan view of a shadow mask according to the first embodiment. The shadow mask 1 is made of a metal material such as Invar alloy or iron,
It is composed of a substantially rectangular thin plate having a thickness of 0.05 to 0.3 mm. At the center of the shadow mask 1, a perforated region 3 having a large number of fine through holes 2 through which an electron beam passes is formed. The arrangement state of the through holes 2 may be the same as that of the ordinary shadow mask 1. For example, the elongated through holes 2 are arranged in a zigzag pattern. A peripheral region 4 for blocking passage of an electron beam is formed outside the perforated region 3. The peripheral region 4 also has a function as a gripping margin for applying tension to the shadow mask 1 when fixing the shadow mask 1 to the support 5, and the width thereof is usually set in the range of 30 to 100 mm. A semicircular positioning hole 9 for positioning is formed near the center of the outer periphery of the long side of the shadow mask 1. The location and size of the positioning hole 9 may be set as appropriate, for example, at the central portion of the outer periphery of the short side of the shadow mask 1, and the shape may be a triangular shape instead of a semicircular shape.

When the shadow mask 1 is in a tensioned state, the side edges of the outer periphery of the shadow mask 1 are the upper ends 8 of the long sides of the support 5 (not shown in FIG.
It is welded and fixed to (described later in FIG. 3). Although the upper end surface 8 of the support 5 that supports the shadow mask 1 is substantially flat, it may be slightly curved. Specifically, in the support 5, the upper end surface 8 of the long-side support 6 is curved along the length direction so that the center is high and both sides are low.

When the shadow mask 1 is fixed on the support 5, first, the pre-tension P ₁ is applied to the four corners of the shadow mask 1 in the oblique direction with respect to the sides of the shadow mask 1 and outward. . In the present invention, the pre-tension P ₁ is applied to the shadow mask 1 in two steps. In the first stage, the first stretched portion 1 provided at the four corners of the shadow mask 1 with the positioning hole 9 and the reference pin 12 engaged with each other.
With 0, a first pre-tension P ₁ is applied diagonally outward to the side of the shadow mask 1. The angle in the oblique direction is set to 15 to 45 degrees with respect to the long side of the shadow mask 1, and preferably 20 to 35 degrees. By applying the preliminary tension P ₁ , tension is applied to the shadow mask 1 in both the long side direction (X direction) and the short side direction (Y direction). Further, the tensile force at this time is gradually increased from 0.098 N while maintaining the engagement state between the positioning hole 9 and the reference pin 12 so that the tension at the four corners has a predetermined value. For example, when it reaches 4.9 N, it pauses. Next, in the second step, the preliminary tension P ₁ is increased to a second predetermined value while applying tension evenly to the four corners.
9.8-98N is suitable as the second predetermined value. In the second stage, the positioning hole 9 and the reference pin 12 are put in the engaged state, but it is not always necessary to keep the engaged state.

The shadow mask 1 and the support 5 are brought into contact with each other in the state where the preliminary tension P ₁ is applied, and the asserting force P ₂ is applied in the direction perpendicular to the long side direction (X direction) of the shadow mask 1. The shadow mask 1 is welded and fixed to the upper surface 8 of the long side of the support 5 while applying the main tension P ₂ .

Incidentally, as is generally done in the past, a compressive force may be applied in advance to the support 5 to which the shadow mask 1 is attached in the Y direction. 1 of support 5
A compressive force is applied between the pair of opposed long side supports 6 in a direction of narrowing the interval between the long side supports 6. The shadow mask 1 in the state in which the pre-tension P ₁ and the assertion force P ₂ are applied is attached to the support 5 in the state in which the compression force is applied. In the pasted state, the shadow mask 1 tries to shrink to its original size, and the support 5 tries to expand to its original size. So-called restoring force acts to balance the two, that is, the shadow mask 1 Is stable in a state where the compressive stress generated on the substrate 5 and the tensile stress generated on the support 5 are balanced.

When the preliminary tension P ₁ is applied to the shadow mask 1, the shadow mask 1 is divided into two steps. In the first step, the four corners of the shadow mask 1 are pulled with a relatively small pulling force. As a result, the shadow mask 1 and the support 5 are accurately positioned without applying an excessive force to the shadow mask 1 in the vicinity of the positioning hole 9 engaged with the reference pin 12. That is, it is possible to prevent the distortion caused by the force received from the reference pin 12 with which the shadow mask 1 is engaged. In the second stage, the tensile force is applied to the four corners of the shadow mask 1 with an even greater tensile force, so that the shadow mask 1 is evenly tensioned while the positional relationship between the shadow mask 1 and the support 5 is accurately maintained. multiply. As a result, it is possible to suppress the generation of wrinkles and distortion even after the heat treatment of the shadow mask 1.

The support 5 of the present invention may basically have the same structure as that of the conventional example shown in FIG. The support 5 is composed of a pair of long side supports 6 and a pair of short side supports 7 each of which is made of a type steel material and is assembled in a cross beam shape. The upper end surface 8 of the long-side support 6 is slightly curved along its length, and its center is high and is low toward both sides. The shadow mask 1 is tensioned by a first tensioning step and a second tensioning step, which will be described later, and then fixed to the upper end surface 8 of the long side support 6 by welding.

<First Tensile Step> FIGS. 2 (a) and 2 (b)
Shows a main part of the apparatus for manufacturing a cathode ray tube according to the present invention. In the first pulling step, first, as shown in FIG. 2A, the pretension P _{1 is applied} to the shadow mask 1 in the X direction, that is, the long side thereof, by the stretched portions 10 arranged near the four corners of the shadow mask 1. It is added in the outward direction with a positional relationship of angle α with respect to the direction. The tension component applied in the X direction and the Y direction of the shadow mask 1 can be changed by setting the angle α for applying the preliminary tension P ₁ . Claiming force P ₂ is tensioned in the Y direction of the shadow mask 1, but will be given a tension component in the X direction perpendicular to the Y direction of the shadow mask 1 by applying a pre-tension P _1, the angle α By appropriately setting, it is possible to suppress the unevenness generated in the shadow mask 1 which could not be achieved by pulling only with the assertive force P ₂ .

The stretcher 10 detects the clamp 15 and the tension.
Load cell 20, wire 16, and wire for
It is composed of a motor 17 for winding 16
And load cell 20 and motor 17 on wire 16
More connected. The clamp 15 is as shown in FIG.
In addition, it comprises a pair of upper and lower clamping pieces 13, 14. Sandwiching piece 1
3 and 14 have steps, and bite between these steps
Combine them so that they fit between the sandwiching pieces 13 and 14.
Insert a part of the mask mask 1 and press it from above and below
It In this state, wind the wire 16 with the motor-17
Take, pre-tension P ₁Is outside the long side of shadow mask 1
Add to the side. Pre-tension P₁Is the stretcher 10
It is detected by the constituent load cell 20.

The preliminary tension P ₁ is applied to the four corners of the shadow mask 1 in two steps. That is, in the first step, while the positioning hole 9 provided on the long side of the shadow mask 1 and the reference pin 12 are held by the first stretching means so as to maintain the engaged state, Tension is applied until the corner tension reaches a first predetermined value (eg 0.49N). In this process, the tensions of the stretched portions 10 provided at the four corners are not always uniform due to the slack and wrinkle states near the four corners of the shadow mask 1.

When it is confirmed that the tensions at the four corners of the shadow mask 1 have reached 0.49N, for example, the first tension portion 10 applies the tension of the second stage. In the second stage, the tension is uniformly applied to the four corners by the tension portion 10 and the tension is increased to a second predetermined value (for example, 1.47N). The pre-tension P ₁ is generally set to ₂ to 30% of the asserted force P ₂ .

As shown in FIG. 3, the shadow mask 1 tensioned in the above state is brought into contact with the upper end surface 8 of the long side support 6 of the support 5. When the shadow mask 1 is arranged along the long side support 6 having the curved upper end surface 8, the pre-tension P ₁ is applied slightly downward with respect to the horizontal direction. That is, the direction of the pre-tension P ₁ is set within the extended surface obtained by extending the surface of the shadow mask 1 arranged along the long side support 6 to the outside. Therefore, the pretension P ₁ has an angle β with the horizontal direction. The angle β is determined by the curved state of the upper end surface 8 of the long side support 6.

Due to the pretension P ₁ , the shadow mask 1
Is placed in a tensioned state along the shape of the upper end surface of the support 5, that is, the shape of the gently curved surface of the long side support 6.

Since the force exerted by the preliminary tension P ₁ on the shadow mask 1 includes both the X-direction component and the Y-direction component, the shadow mask 1 has an accurate surface in a tensioned state in which balance is maintained in all surface directions. Put in shape.

The apparatus for manufacturing a cathode ray tube of the present invention can sufficiently exert its effect by performing the above-mentioned first drawing step. However, if the second tensioning step described below is performed, the effect is further improved.

<Second Tensioning Step> The second tensioning step is characterized by applying an assertive force in the direction perpendicular to the long side of the shadow mask 1. Details will be described below with reference to FIG. As shown in FIG. 4, the reference pin 12 engaged with the positioning hole 9 provided in a part of the shadow mask 1 is moved to apply the preliminary tension P ₁ to the shadow mask 1.
The pulling tool 1 for gripping each other over substantially the entire length of the opposite long sides.
1 is used to apply a strong tensile assertion force P ₂ to the outside in the direction perpendicular to the long side. A suitable main tension P ₂ is 9.8 to 4900N. The pulling tool 11 is a part of the second stretching means of the present invention.

The magnitudes of the pretension P ₁ and the assertion force P ₂ in the first tensioning step and the second tensioning step can be set within the ranges described above, but these magnitudes are It is appropriately adjusted depending on the size of the shadow mask assembly and the material of the shadow mask.

The structure of the pulling tool 11 may be the same as the holding tool 15 used in the pre-pulling step. When the upper end surface 8 of the support 5 is curved and the shadow mask 1 is arranged in a curved state, the pulling tool 11 is also preferably capable of grasping and pulling the shadow mask 1 in the curved state. Therefore, the shape of the pulling tool 11 is also curved along the curved shape of the long-side support body 6.

While the pre-tension P ₁ and the asserting force P ₂ are applied to the shadow mask 1, the shadow mask 1 is supported in a tensioned state along the curved surface of the long side support upper end surface 8 of the support body 5, and the shadow mask 1 is supported. The long side support 6 is welded and fixed. The shadow mask 1 to which the support 5 is attached in this manner is subjected to a process of cutting and removing an unnecessary portion of the shadow mask 1 outside the support 5 and a heat treatment process. The solid is completed.

As described above, when the pre-tension is applied to the shadow mask 1 in two steps, the tension is applied in two steps, so that the shadow mask 1 and the support are accurately maintained in the positional relationship. A uniform tension can be applied to the. As a result, it is possible to prevent the generation of wrinkles and distortion even after the heat treatment of the shadow mask 1.

(Embodiment 2) This embodiment is shown in FIG. A pretension P ₁ is applied to the four corners of the shadow mask 1 by the stretched portions 10 in the direction from the long side direction of the shadow mask 1 to the outside. The assertive force P ₂ is further applied in the Y direction of the shadow mask 1 with the preliminary tension P ₁ being applied. When the tension is applied to the shadow mask 1, it is the same as the first embodiment in that it has a first tensioning step and a second tensioning step. The difference from the first embodiment is that the shadow mask 1 has a first tensioning portion 10 that applies a preliminary tension P ₁ and a tensioning device 1 that applies a asserting force P ₂ to form a second tensioning means.
1 is arranged on the same substrate 18.

According to this structure, since the stretched portion 10 is arranged on the same substrate as the main pulling tool 11, it moves by the same amount as the moving amount of the main pulling tool 11, and the value of the preliminary tension P ₁ is Is kept constant. Therefore, the tension applied to the shadow mask 1 can be kept uniform.

In the second pulling step, the shadow mask 1 is applied by the asserting force P ₂ applied by the main pulling tool 11.
Is stretched in the P ₂ direction and the main pulling tool 11 can move in the P ₂ direction, so that the interference generated between the pretension P ₁ and the asserted force P ₂ can be suppressed.

(Third Embodiment) The basic configuration of the third embodiment is almost the same as that of the first or second embodiment. The difference from these is that the pre-tension P is applied to the shadow mask 1.
_The point is that a detection means is provided for detecting the amount of expansion of the shadow mask 1 when ₁ and the asserting force P ₂ are applied.

As shown in FIG. 2, at the four corners of the peripheral region 4 of the shadow mask 1 and in the vicinity of the stretched portion 10, there are provided position detection patterns 19 constituted by, for example, cross-shaped notches. The position detection patterns 19 are preferably formed at the four corners of the shadow mask 1, but diagonally,
Alternatively, it may be provided at two positions above and below, and the shape may not be a cross shape, but may be, for example, a rectangular shape, an L shape, or a circular shape.

A detection means (not shown) for detecting the moving distance of the position detection pattern 19 is arranged below the shadow mask 1. The detection means is composed of a light emitter such as a light emitting diode and a photodetector such as a phototransistor arranged above and below the detection pattern 19 via a shadow mask, and detects the amount of movement of the detection pattern 19 by the output of the photodetector. To do. With the above configuration, it is possible to detect the extension amount of the shadow mask 1 from the state in which the tension of the first stage of the preliminary tension P ₁ is applied to the time when the assertive force P ₂ is applied.

With such a structure, even if the material characteristics such as the thickness and the rigidity of the shadow mask 1 are changed or fluctuated due to the manufacturing variations, that is, the difference of the material of the shadow mask 1 or the lot, the deviation is immediately known. be able to. By controlling the pretension P ₁ and the assertion force P ₂ so that the movement distance of the position detection pattern 19 is constant, a stable shadow mask assembly, that is, a cathode ray tube is manufactured even if the material characteristics change. be able to.

The first embodiment, the second embodiment, and the third embodiment have been described above, but they are summarized as follows.

(1) A tensile force is applied to the four corners of a shadow mask having a sheet-shaped shadow mask having a region having a large number of through holes obliquely outward with respect to the sides of the shadow mask. The apparatus for manufacturing a cathode line according to claim 1, wherein the first stretching means is configured to apply the tensile force in two stages having different tensile forces.

(2) An apparatus for manufacturing a cathode ray tube provided with a second elongating means for applying a tensile force in a direction perpendicular to the long side of the shadow mask.

(3) An apparatus for manufacturing a cathode ray tube in which the first stretching means and the second stretching means are arranged on the same substrate.

(4) An apparatus for manufacturing a cathode ray tube, wherein a detecting means for detecting the extension of the shadow mask is provided around the corner of the shadow mask.

(5) On a support having a substantially rectangular frame shape,
A cathode ray tube comprising a sheet-shaped shadow mask having a region having a large number of through holes, wherein the sheet-shaped shadow mask is provided with a pattern in at least one corner.

(6) On a support having a substantially rectangular frame shape,
A method of manufacturing a cathode ray tube, wherein a sheet-shaped shadow mask having a region having a large number of through holes is attached, wherein the shadow mask is positioned on the support while the shadow mask is applied to four corners of the shadow mask. A step (a) of applying a predetermined tensile force obliquely outward to the side of the mask, and a step (b) of applying a tensile force larger than the predetermined tensile force to the shadow mask after the step (a). A method of manufacturing a cathode ray tube including the.

(7) A method of manufacturing a cathode ray tube comprising a step (c) of adding a second stretching means for applying a tensile force in a direction perpendicular to the long side piece of the shadow mask after the step (b).

(8) A step of detecting the expansion of the shadow mask near at least one corner of the shadow mask is provided, and at least the steps (a), (b) and (c) are performed by the detected expansion. A method of manufacturing a cathode ray tube, comprising the step of controlling one tensile force.

(9) Tensile forces in the steps (a) and (b) are 0.098 to 4.9 N and 9.8 to, respectively.
A method of manufacturing a cathode ray tube which is 490N.

[0049]

In the cathode ray tube manufacturing apparatus according to the present invention, the pre-tension and the asserting force are applied to the shadow mask to bring it into a tensioned state, and the welding is fixed to the support. At this time, by applying the tension in two steps, it is possible to apply a uniform tension to the shadow mask in a state where the positional relationship between the shadow mask and the support is accurately maintained. As a result, it is possible to provide a cathode ray tube in which generation of wrinkles and distortion is suppressed even after the heat treatment of the shadow mask.

In addition to the shadow mask, the first tensioning portion for applying the pretension and the tensioning member constituting the second tensioning means for applying the assertive force are provided on the same substrate. The tension applied can be made uniform.

Further, by detecting the moving distance of the four corners of the shadow mask by applying tension and controlling the tension based on this, the shadow mask assembly is stable even when the material characteristics of the shadow mask change. Can be made.

[Brief description of drawings]

FIG. 1 is a diagram showing a state in which a tensile force is applied to a shadow mask used in a cathode ray tube according to an embodiment of the present invention.

FIG. 2A is a diagram showing a cathode ray tube manufacturing apparatus according to an embodiment of the present invention, and FIG. 2B is a diagram showing a holding tool which is a part of the cathode ray tube manufacturing apparatus according to the embodiment of the present invention.

FIG. 3 is a side view showing a method of manufacturing a cathode ray tube according to the present invention.

FIG. 4 is a plan view showing a method for manufacturing a cathode ray tube according to the present invention.

FIG. 5 is a view showing an assembly of a shadow mask which constitutes the cathode ray tube of the present invention.

FIG. 6 is a diagram showing a cathode ray tube manufacturing apparatus and manufacturing method of the present invention.

FIG. 7 is a diagram showing a method for fixing a conventional shadow mask to a support.

FIG. 8 is a diagram showing a method of giving a tension state to a conventional shadow mask.

[Explanation of symbols]

1 Shadow Mask 2 Through Hole 3 Perforated Area 4 Peripheral Area 5 Support 6 Long Side Support 7 Short Side Support 8 Long Side Upper End 9 Positioning Hole 10 Stretching Part 11 Pulling Tool 12 Reference Pin 13 Clamping Piece 14 Clamping Piece 15 clamp 16 wire 17 motor 18 substrate 19 position detection pattern 20 load cell P ₁ preliminary tension P ₂ assertion force

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kiyotaka Ihara             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Toshiyuki Kitagawa             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Otsuka Kyo             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. F term (reference) 5C027 HH23                 5C031 EE03 EH05

Claims (9)

[Claims] 1. A four-corner portion of a sheet-shaped shadow mask having a region having a large number of through holes is provided with first stretching means for applying a tensile force obliquely outward to a side of the shadow mask. The apparatus for manufacturing a cathode ray tube, wherein the first stretching means is configured to apply a tensile force in two stages having different tensile forces. 2. The cathode ray tube manufacturing apparatus according to claim 1, further comprising a second elongating means for applying a tensile force in a direction perpendicular to the long side of the shadow mask. 3. The apparatus for manufacturing a cathode ray tube according to claim 2, wherein the first stretching means and the second stretching means are arranged on the same substrate. 4. The apparatus for manufacturing a cathode ray tube according to claim 1, further comprising detection means around the corner of the shadow mask for detecting the expansion of the shadow mask. 5. A cathode ray tube comprising a sheet-shaped shadow mask having a region having a large number of through holes on a support body having a substantially rectangular frame shape, wherein at least one of the sheet-shaped shadow masks is provided. A cathode ray tube characterized in that a pattern is provided in a corner. 6. A method of manufacturing a cathode ray tube comprising a sheet-shaped shadow mask having a region having a large number of through holes attached to a support having a substantially rectangular frame shape, the shadow mask being provided on the support. And (a) applying a predetermined tensile force to the four corners of the shadow mask in a diagonally outward direction with respect to the sides of the shadow mask while positioning
A method of manufacturing a cathode ray tube, comprising a step (b) of applying a tensile force larger than the predetermined tensile force to the shadow mask after (a). 7. The method of manufacturing a cathode ray tube according to claim 6, further comprising a step (c) of applying a tensile force in a direction perpendicular to the long side of the shadow mask after the step (b). 8. A step of detecting the extension of the shadow mask near at least one corner of the shadow mask, wherein the step (a), the step (b) and the step (c) are detected by the detected extension of the shadow mask. 8. The method for manufacturing a cathode ray tube according to claim 6, further comprising the step of controlling at least one of the pulling forces in 1). 9. The tensile forces in the step (a) and the step (b) are 0.098 to 4.9 N and 9.8 to 4, respectively.
It is 90 N, The manufacturing method of the cathode ray tube in any one of Claims 6-8.