JP2001155655A - Color cathode ray tube and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color cathode ray tube including shadow mask structure, in which wrinkles and distortions do not occur in the hole part of the mask due to the rough parts or stress of the mask welding part, and its manufacturing method. SOLUTION: In the color cathode ray tube having a shadow mask structure 1 in which a shadow mask 2 is hooked and welded on a pair of opposite mask frames 6 on tension, the mask frames 6 include a plane 6a which supports and arranges the circumference part 2a of the shadow mask and a plane 6b which is a plane part for welding the end of the shadow mask, and a slope face 10a of the roller seam electrode 10 being contacted tightly and welded to the edge 6d of the plane 6b by inserting mask 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color cathode ray tube and a method of manufacturing the same, and more particularly, to a color cathode ray tube in which a shadow mask having an electron beam passage hole is stretched and fixed to a mask frame by welding. .

[0002]

2. Description of the Related Art A color cathode ray tube 21 suitable for displaying an image such as a computer terminal display or a high-definition television.
Has a structure as shown in FIG. That is, it has a bulb 25 in which the face panel 22 and the funnel 23 are integrally joined by the frit glass 24, and phosphors that emit green, blue, and red light are arranged in the form of dots or stripes inside the face panel 22. The provided phosphor screen 26 is applied and formed, and behind the phosphor screen 26, a shadow mask (hereinafter, referred to as a mask) 27 having a large number of electron beam passage holes (aperture grill type, passage hole). A shadow mask structure (hereinafter, referred to as a mask structure) 29 in which a dot having a dot and a bridge portion, and the like, are fixed to a mask frame (hereinafter, referred to as a frame) 28 at a constant interval from the inner surface of the panel. Have been. The mask structure 29 includes a hook spring 32 formed on a side wall of the frame 28 and a stud pin 22 a implanted on a side inner wall of the face panel 22.
Is fixed to the face panel 22. An electron gun 31 that emits three electron beams is provided in the neck portion 30 of the funnel. A deflection yoke 33 is provided outside the cone of the funnel in front of the electron gun 31.

The color cathode ray tube 2 constructed as described above
In FIG. 1, three electron beams R, G, and B emitted from an electron gun 31 are deflected in a horizontal direction and a vertical direction by a deflection yoke 33, are selected in color by a mask 27, and are then subjected to a predetermined process on a phosphor screen 26. The image is displayed by illuminating the phosphor film by emitting light.

A typical representative mask structure in the prior art is, for example, an aperture grill type disclosed in Japanese Patent Application Laid-Open No. 6-314547. As shown in the perspective view of FIG. 9, the opposite ends of an aperture grill type mask 27a provided with a plurality of grid elements 34 at a predetermined pitch are formed by a pair of opposite frames having a gentle curvature in the z direction. It is manufactured by welding and fixing it on a stretched state on 28a, 28b. Further, in order to prevent or attenuate the vibration of the mask, a plurality of damper lines 35 are provided so as to intersect and adhere to the grid element 34.

However, in the color cathode ray tube provided with the aperture grill type mask structure constructed as described above, since a plurality of damper wires 35 are stretched across the opening through which the electron beam passes, x Since the electron beam scanned in the direction collides and scatters with the damper line 35 and does not strike the corresponding fluorescent film, the fluorescent film does not emit light, the shadow of the damper line is reflected on the image display surface, and the display quality deteriorates. was there. Therefore, a color cathode ray tube for solving this problem is disclosed, for example, in Japanese Patent Application Laid-Open No. 8-227667. FIG. 10 is a perspective view of a mask structure used in the color cathode ray tube. As shown in FIG. 10, the electron beam passage hole 36 which is discontinuously opened and the horizontal scanning direction (x direction) of the electron beam are used. The opposite end of the slot type mask 27b having the grill portion 37 extending in the direction (y direction) orthogonal to the above and the bridge portion 38 connecting these adjacent grill portions is formed by gently changing the curvature in the z direction. And is welded and fixed in a stretched state on a pair of opposed frames 28a and 28b having In particular, it is characterized in that an anti-vibration wire (damper wire) 39 is stretched over the grill portion 37 extending to the perforated area. In this configuration, since the damper line does not cross the electron beam passage hole, no shadow of the damper line occurs.

Next, a method of fixing the mask will be described by taking a slot type mask as an example. In FIG. 11, a pair of support frames 28 supporting the frames 28a and 28b are shown.
c and 28d are made of a member having elasticity, and a force is applied from the outside in the y direction as shown by an arrow so that the interval between the frames 28a and 28b is reduced by a predetermined amount by the elastic deformation.
The upper and lower ends of the mask 27b are placed on the frames 28a and 28b, and then a pair of disk-shaped welding electrodes (hereinafter, referred to as roller seam electrodes) 50 are pressed against the upper and lower ends of the mask 27b to move from one end to the other end. The mask 27b is welded and fixed to the frames 28a and 28b by intermittently energizing (applying a pulse) while rotating along a frame having a constant curvature while being pressed, thereby removing the force. Vertical direction to mask 27b (y direction in the figure)
Of tension.

A conventional roller seam electrode is shown in FIG.
2 (a), the electrode width d is smaller than the frame width D, as shown in FIG. 12 (b), the electrode width d is larger than the frame width D, as shown in FIG. 12 (c). There is a method in which a mask is welded to the outer edge of a frame by tilting the entire electrode.

[0008]

The conventional mask fixing method in which the mask is welded by a roller seam electrode while being stretched on a pair of opposed frames has the following problems. That is, as shown in FIG. 12A, when welding is performed with the roller seam electrode 50 in which the electrode width d is smaller than the frame width D, since the diameter D is as small as several millimeters, the electrode comes off during rotation, making welding impossible. Easy to be. FIG.
As shown in FIG. 2B, when welding is performed with the roller seam electrode 50 in which the electrode width d is larger than the frame width D, the pressure and current density are insufficient because the welding area is large when the electrode is normal without inclination. And the welding strength becomes weak. Also, during rotation, the electrode may be tilted to the left or right with respect to the traveling direction. In this case, the welding point becomes dotted, and the welding point moves irregularly between the outer edge and the inner edge of the frame. Wrinkles mainly occur in the y-direction in the mask corresponding to the moving parts of the points, causing unevenness in brightness, unevenness in color, and the like. FIG.
When the electrode 50 is inclined and welded to the outer edge of the frame as shown in FIG. 2 (c), a mechanism for arranging the electrode is required, and the mechanism of the welding device becomes complicated, which is disadvantageous for cost and maintenance. Become.

Further, the above-mentioned welding with the roller seam electrode has the following common problems. FIG.
FIG. 3 is a schematic view showing the state of the mask 27 during welding. As shown in FIG. 13A, prior to welding, when the electrode 50 is first pressed against the mask 27 placed on the frame 28, a pressure contact is made. The mask on one side (or both sides) is warped upward, causing the mask to float. Next, as shown in FIG. 13B, when the electrode 50 is rotated and welding is sequentially performed from one end to the other end of the mask, the mask is lifted and welded. Stress remains in the part. Further, since the welded portions are discontinuous, a fine float is formed between the welded portions, and irregularities 40 are formed in the welded portions of the mask. Due to the unevenness and stress of the mask at the weld, wrinkles and twists occur in the perforated part of the mask,
Image quality is degraded.

Accordingly, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a novel mask which does not cause wrinkles and twists in a perforated portion of a mask due to unevenness and stress of the mask at a welded portion. A color cathode ray tube having a structure,
It is an object of the present invention to provide a manufacturing method thereof.

[0011]

According to the present invention, there is provided a color cathode ray tube having a mask structure in which a mask is stretched over a pair of opposed frames and fixed by welding.
The frame is formed with a support portion for supporting and positioning the peripheral portion of the mask and a welding portion for welding the peripheral portion of the mask. According to this configuration, the supporting portion for supporting and positioning the mask and the welding portion for fixing the mask are separated, and the welding portion is located outside and behind the supporting portion (below the mask opening surface). are doing. Therefore, even if a defect occurs in the welded portion using a conventional roller seam electrode as shown in FIG. 12, for example, it is possible to prevent wrinkles in the peripheral portion of the mask or the perforated portion of the mask, adverse effects such as residual stress, and the like. Deterioration of image quality can be prevented.

Further, the color cathode ray tube of the present invention is characterized in that the welded portion is an edge located outside the supporting portion and below the perforated surface of the mask.
According to this configuration, the mask can be stretched with sufficient tension, supported by the support portion, positioned, and fixed by the welded portion. The support is separate from the weld that fixes the mask, and the weld is an edge located outside and behind (below the mask aperture) below the support. Therefore, even if a defect occurs in the welded portion using the conventional roller seam electrode, the effect is blocked by the mask support portion,
There is no adverse effect such as wrinkles and residual stress on the perforated portion of the mask beyond that. In addition, since the welding is performed on the edge of the frame with a pulse, the welding is performed in a point-like manner, and the welding strength is improved. Also, since the welding point does not change because the edge is linear,
The generation of wrinkles can be prevented.

In the color cathode ray tube of the present invention, a flat supporting portion and a flat welding portion are formed as steps on a frame, and a mask is stretched over the steps.
The mask is welded to the outer edge of the plane of the welded portion. According to this configuration, the mask position is stably supported by the support portion having a stable shape formed of a flat surface. Also, since it is welded to the edge of the frame with a pulse,
It is welded in a point-like manner and the welding strength is improved. Further, since the welding point does not fluctuate, wrinkling can be prevented.

Further, in the color cathode ray tube of the present invention, a mask is stretched on an inclined surface formed on the frame, and an inner edge formed by the inclined surface and the inner surface of the frame is a supporting portion, The outer edge formed by the surface and the outer surface of the frame is a weld. According to this configuration, since the mask is positioned at the linear edge of the frame, the positioning accuracy is improved. Further, since welding is performed on the edge of the frame with a pulse, the welding is performed in a point-like manner, and the welding strength is improved. Further, since the welding point does not fluctuate, wrinkling can be prevented.

In the color cathode ray tube according to the present invention, a mask frame has a support portion formed of a flat surface and a welded portion formed of an inclined surface, and a shadow mask is extended from the flat surface to the inclined surface. A mask is welded to an outer edge formed by the outer surface of the mask. Also in this configuration, the mask position is stably supported by the support portion having a stable shape formed of a flat surface. Further, since welding is performed on the edge of the frame with a pulse, the welding is performed in a point-like manner, and the welding strength is improved. Further, since the welding point does not fluctuate, wrinkling can be prevented.

Further, in the color cathode ray tube of the present invention, a first projection and a second projection lower than the first projection are formed on the frame, the first projection is a support portion, and the second projection is It is a welded part. According to this configuration, in addition to the above-described functions and effects, by optimizing the groove width and the groove depth between the first protrusion and the second protrusion, elasticity (spring property) is given to the protrusion, There is an effect that the tension of the mask 2 can be adjusted.

Further, the method of manufacturing a color cathode ray tube according to the present invention includes the step of stretching the mask on a pair of opposed frames and fixing the mask with a roller seam electrode. The portion is supported by a supporting portion formed on the frame, the edge of the peripheral portion of the mask is brought into contact with the edge formed on the frame, and the mask is welded to the edge with the inclined surface of the roller seam electrode. . According to this configuration, the mask is welded to the edge on the inclined surface of the roller seam electrode, so that the welding location becomes dotted and the welding strength is improved, and the welding position does not fluctuate and wrinkling can be prevented. Further, by forming the inclined surface on the roller seam electrode, it is not necessary to incline the electrode itself as in the related art, and the mechanism does not become complicated.

Further, in the method of manufacturing a color cathode ray tube according to the present invention, the gradient of the inclined surface of the roller seam electrode is larger than the gradient of the mask disposed between the supporting portion and the edge. According to this configuration, at the time of welding, the electrode, the mask, and the frame come into contact at one point, so that the welding location becomes dotted and the welding strength is improved, and the welding position does not fluctuate and wrinkling can be prevented. Further, the tension is not loosened due to the non-welded portion of the mask being pushed by the electrode.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a color cathode ray tube having a mask structure in which a mask is stretched over a pair of opposed frames and fixed by welding, and a method of manufacturing the same.
The characteristic part of the color cathode ray tube is in the structure of the mask structure,
Especially in the shape of the frame. That is, the frame according to the present invention is characterized in that a support portion for supporting and positioning the peripheral portion of the mask and a welding portion for welding the end portion of the peripheral portion of the mask are separately formed. In a conventional frame, both were used. Also, the characteristic part of the manufacturing method is that the welding surface of the roller seam electrode is an inclined surface, the electrode itself is not inclined, the inclined surface is pressed against the edge of the frame via a mask, and a pulse is applied. It is to spot-weld the mask.

Hereinafter, a first embodiment of the color cathode ray tube of the present invention will be described with reference to FIGS. FIG.
Is a mask structure 1 mounted on the color cathode ray tube of the present invention.
FIG. 5 is an enlarged perspective view of a partially cut-away main part when viewed from the front side of the mask. FIG. 2 is an enlarged sectional view of a main part along line AA in FIG. The figure also shows a roller seam electrode 10 used for welding the mask. As shown in FIG. 1, for example, a slot type mask 2 has a slot-shaped electron beam passage hole 3 and a grill portion extending in a direction (y direction) orthogonal to a horizontal scanning direction (x direction) of the electron beam. 4 and a bridge portion 5 connecting adjacent grill portions. Due to the presence of the bridge portion 5, the slot type mask 2
Are connected in the horizontal direction (x direction). The slot type mask 2 is fixed on a pair of frames 6 by being stretched in a direction in which the grill extends (y direction).

On the side of the frame 6 on which the mask is stretched, a supporting portion consisting of the flat surface 6a and a welding portion consisting of the flat surface 6b are formed as steps with a gentle curvature along the longitudinal direction of the frame. The peripheral edge portion 2a of the mask 2 is supported on the flat surface 6a in contact with the mask, the mask is positioned in accordance with the gentle curvature of the frame, and the shadow mask 2 is stretched over the step. Since there is no welding at the support,
No unevenness or residual stress is formed on the mask of the support portion. The peripheral edge 2 of the mask 2 is attached to the outer edge 6d of the flat surface 6b of the weld.
The end 2b of a is welded. In this way, the supporting portion for supporting and positioning the mask and the welding portion for fixing the mask are separated, and the welding portion is located outside and behind the supporting portion (below the mask opening surface). I have. According to this configuration, the mask position is stably supported by the support portion having the stable shape composed of the flat surface 6a. In addition, since welding is performed on the edge 6d of the frame with a pulse, the welding is performed in a point-like manner, and the welding strength is improved. Also, since the edge is linear, the welding point 7 does not fluctuate, so that generation of wrinkles can be prevented. Even if a defect occurs in the welded portion using the conventional roller seam electrode as shown in FIG. 12, the defect is interrupted by the support portion, and the adverse effects such as wrinkles and residual stress on the mask peripheral portion 2a and the perforated portion of the mask are caused. Ripple is prevented.

When the mask is welded to the outer edge of the frame, the roller seam electrode 10 having an inclined surface described below is preferable as the roller seam electrode. As shown in FIG. 2, the roller seam electrode 10 has a welding surface formed as an inclined surface 10 a, and the inclined surface 10 a is formed on the edge 6 d formed by the plane 6 b and the outer surface 6 c of the frame 6 via the mask 2. The mask 2 is welded and fixed to the frame 6 by being pressed and intermittently energized. Roller seam electrode 1
Since the welding is performed on the edge with the 0 inclined surface 10a, the welding location 7 becomes dotted as shown in FIG. 1 and the welding strength is improved, and the welding position does not change and wrinkles can be prevented.
Further, by forming the inclined surface 10a on the roller seam electrode 10, there is no need to incline the electrode itself as in the conventional case of FIG. 12C, and the mechanism does not become complicated. In order to enable spot welding at the edge 6d, the gradient of the inclined surface 10a of the roller seam electrode 10 needs to be greater than the gradient of the mask due to the step. That is,
In FIG. 2, the inclined surface 10a of the roller seam electrode 10 is shown.
Should be set so that θ> 0. In this way, electrodes, masks,
The edges are superimposed at one point so that other parts of the electrode do not press against the non-welded portion of the mask to loosen the stretch of the mask.

As a modified example of the frame, when the flat surface 6a is formed to extend to the frame outer surface 6c without forming a step, the entire flat surface 6a is a supporting portion, and the flat surface 6a
The edge 6d formed by a and the outer surface 6c of the frame becomes a weld. Even in the case of such a frame, the manufacturing method of the present invention is effective. That is, using the roller seam electrode 10 described above, a mask is formed on the outer edge 6d of the frame.
Welding without complicating the equipment
Variation of the welding point can be prevented, and the occurrence of wrinkles on the perforated surface of the mask can be reduced.

Next, a second embodiment of the color cathode ray tube of the present invention will be described with reference to the drawings. FIG. 3 is an enlarged sectional view of a main part of a mask structure 8 according to a second embodiment of the present invention. The feature of the second embodiment is that an inclined surface 9a is formed along the longitudinal direction of the frame 9 on the side of the frame 9 where the mask is stretched. The inclined surface 9a
The frame 9 is inclined in a direction perpendicular to the longitudinal direction of the frame (y direction), and is formed with a downward slope from the inner surface 9b side of the frame 9 to the outer surface 9c side. The mask 2 is in contact with the inclined surface 9a of the frame as shown in FIG. In the frame 9 having the above structure, the inner edge 9e formed by the inclined surface 9a and the inner surface 9b of the frame serves as a support portion of the mask 2. Further, an outer edge 9 d formed by the inclined surface 9 a and the frame outer surface 9 c becomes a welded portion of the mask 2. The weld is located outside the support and below the perforated surface of the mask.

The outer edge 9d of the frame 9 having the above structure
When the mask 2 is welded, the roller seam electrode shown in FIGS. 12A and 12B cannot be used. Although the inclined roller seam electrode of FIG. 12C can be used, there is a problem that the mechanism becomes complicated. The most preferred roller seam electrode is the beveled roller seam electrode 10 of the present invention shown in FIG. The mask 2 can be welded and fixed to the frame 9 by pressing the inclined surface 10a against the outer edge 9d of the frame 9 via the mask 2 and applying current intermittently (pulsing) while rotating. Edge 9d
Roller seam electrode 1
It is necessary that the gradient of the inclined surface 10a of 0 is larger than the gradient of the inclined surface 9a of the frame 9. That is, in FIG. 3, the angle between the inclined surface 10a of the roller seam electrode 10 and the mask inclined surface (the frame inclined surface 9a) should be θ> 0. Also in the second embodiment, since the support portion for supporting and positioning the mask and the weld portion are separated from each other, even if a defect occurs in the weld portion, the mask peripheral portion 2a and the mask hole portion have wrinkles and residual stress. And other adverse effects are prevented. In particular, since welding is performed on the edge of the roller seam electrode 10 at the inclined surface, as shown in FIG. 1, the welding portion 7 becomes dotted and the welding strength is improved, and the welding position is not changed, and wrinkling is prevented. it can. In addition, since the inclined surface is formed on the roller seam electrode 10, it is not necessary to incline the electrode as in the related art, and the mechanism does not become complicated.

Next, a third embodiment of the color cathode ray tube of the present invention will be described with reference to the drawings. FIG. 4 is an enlarged sectional view of a main part of a mask structure 11 according to a third embodiment of the present invention. The feature of the third embodiment is that the frame 1
2, a support portion composed of a flat surface 12a and a welded portion composed of an inclined surface 12b are formed continuously, and
2b, the mask 2 is extended, and an outer edge 1 formed by the inclined surface 12b and the outer surface 12c of the frame 12 is formed.
The mask is welded to 2d. Also in the third embodiment, the mask position is stably supported by the support having a stable shape composed of the flat surface 12a. Also, since it is welded to the edge 12d of the frame with a pulse,
It is welded in a point-like manner and the welding strength is improved. Further, since the welding point does not fluctuate, wrinkling can be prevented.

Next, a fourth embodiment of the color cathode ray tube of the present invention will be described with reference to the drawings. FIG. 5 is an enlarged sectional view of a main part of a mask structure 13 according to a fourth embodiment of the present invention. The feature of the fourth embodiment is that the frame 1
A first projection 15 is formed on the side on which the mask 4 is stretched, and a second projection 16 having a lower height is formed outside the first projection 15 along the longitudinal direction of the frame. Reference numeral 15 denotes a supporting portion of the mask 2, and the second protrusion 16 serves as a welding portion. The upper surface of the first protrusion 15 may be a flat surface, and the upper surface of the second protrusion 16 may be a flat surface or an inclined surface. The mask 2 is desirably welded to the outer edge 16d of the second projection using the roller seam electrode 10. In the fourth embodiment, the same operation and effect as in the first embodiment can be obtained. Furthermore, by optimizing the groove width and groove depth between the first protrusion 15 and the second protrusion 16, the elasticity (spring property) is given to the protrusion, and the effect of adjusting the tension of the mask 2 can be obtained. is there.

Next, a modification of the color cathode ray tube according to the fourth embodiment of the present invention will be described with reference to the drawings. FIG.
Is an enlarged sectional view of a main part of a mask structure 13 'according to this modification. The feature of the modification is that the upper surface of the first projection 15 'of the fourth embodiment is an inclined surface. The upper surface of the second protrusion 16 'having a lower height than this may be flat or may be an inclined surface. The mask 2 is preferably welded to the outer edge 16'd of the second projection using a roller seam electrode 10. In this modification, the same operation and effect as those of the first embodiment can be obtained. Further, the first projection 1
By optimizing the groove between 5 'and the second protrusion 16', there is an effect that elasticity (spring property) is given to the protrusion and the tension of the mask 2 can be adjusted.

Next, a method of manufacturing the color cathode ray tube of the present invention will be described. In this manufacturing method, as shown in FIG. 7, in a state where the mask 2 is stretched on a plane 17a of a pair of opposed frames 17, the mask ends are connected to the outer surface 17c of the frame.
The mask is welded and fixed to the edge 17d with the roller seam electrode 10 in contact with the side edge 17d and the welding surface is the inclined surface 10a. In the frame 17, the flat surface 17a is a supporting portion for supporting and positioning the peripheral portion of the mask, and the edge 17d is a welding portion. In this case, it is desirable that the angle between the mask of the supporting portion and the inclined surface 10a of the electrode is θ> 0. According to this configuration, the edge is welded with a pulse on the inclined surface of the roller seam electrode, so that the welded portion becomes dotted and the welding strength is improved. Also, by forming an inclined surface on the roller seam electrode, there is no need to incline the electrode itself as in the past,
The mechanism of the device is not complicated. According to the manufacturing method of the present invention, the shape of the frame is the flat surface 1 shown in FIG.
7a is not limited. In particular, as shown in FIGS. 2 to 6, if the support portion and the welded portion are formed into a frame having a separated shape, even if a defect occurs in the mask at the welded portion, the mask is cut off at the support portion. The perforated part is not adversely affected.

[0030]

According to the color cathode ray tube of the present invention, there is provided a color cathode ray tube having a mask structure in which a mask is stretched over a pair of opposed frames and fixed by welding, wherein the frame supports a peripheral portion of the mask. It is characterized in that a supporting portion for positioning and a welding portion for welding an end of a peripheral portion of the mask are formed. With this configuration, the support portion that supports and positions the mask and the weld portion that fixes the mask are separated, and the weld portion is located outside and behind the support portion (below the mask opening surface). ing. Therefore, even when a defect occurs at the welded portion when welding is performed with the roller seam electrode, it is possible to prevent adverse effects such as wrinkles and residual stress on the mask peripheral portion and the mask perforated portion.

Further, the method of manufacturing a color cathode ray tube according to the present invention comprises the step of stretching a mask on a pair of opposed frames and fixing the mask with a roller seam electrode. The support portion for supporting and positioning the peripheral portion of the mask, and a welded portion for welding the end of the peripheral portion of the mask are formed, the welded portion is the edge of the frame, the roller seam electrode The welding surface is an inclined surface, and the inclined surface comes into contact with an edge via a mask to perform welding. According to this configuration, the edge is welded with a pulse on the inclined surface of the roller seam electrode, so that the welded portion becomes dotted and the welding strength is improved, and the welded portion does not fluctuate and wrinkles can be prevented. Further, since the inclined surface is formed on the roller seam electrode, it is not necessary to incline the electrode itself as in the related art, and the mechanism of the apparatus does not become complicated.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing a first embodiment of a shadow mask structure provided in a color cathode ray tube according to the present invention.

FIG. 2 is an enlarged sectional view of a main part along the line AA in FIG. 1;

FIG. 3 is an enlarged sectional view of a main part of a second embodiment of the shadow mask structure provided in the color cathode ray tube of the present invention.

FIG. 4 is an enlarged sectional view of a main part showing a third embodiment of the shadow mask structure provided in the color cathode ray tube of the present invention.

FIG. 5 is an enlarged sectional view of a main part showing a fourth embodiment of the shadow mask structure provided in the color cathode ray tube of the present invention.

FIG. 6 is an enlarged sectional view of a main part showing a modification of the fourth embodiment of the shadow mask structure provided in the color cathode ray tube of the present invention.

FIG. 7 is a sectional view of an essential part for explaining the mask welding method of the present invention.

FIG. 8 is a sectional view including a partial side view of a conventional color cathode ray tube.

FIG. 9 is a perspective view of a shadow mask structure provided in a conventional color cathode ray tube.

FIG. 10 is a perspective view of another shadow mask structure provided in a conventional color cathode ray tube.

FIG. 11 is a perspective view for explaining a conventional mask welding method.

FIG. 12 is a sectional view of a main part for explaining a conventional roller seam electrode.

FIG. 13 is a view for explaining a problem of welding by a conventional roller seam electrode.

[Explanation of symbols]

1, 8, 11, 13, 13 'Shadow mask structure 2 Shadow mask 3 Electron beam passage hole (for example, slot) 4 Grill portion 5 Connection portion of adjacent grill portion 6, 9, 12, 14, 14', 17 Mask frame 6a, 12a, 17a Plane (support) 6b Plane (weld) 6d, 9d, 12d, 16d, 16'd, 17d Edge (weld) 7 Welding point 9a, 12b Slope of frame 9e edge (support) 10 Roller seam electrode 10a Slope of roller seam electrode

Claims (8)

[Claims] 1. A color cathode ray tube having a shadow mask structure in which a shadow mask is stretched over a pair of opposed mask frames and fixed by welding, the mask frame supports and positions a peripheral portion of the shadow mask. And a welded portion for welding a peripheral portion of the shadow mask. 2. The welding part is outside the supporting part, and
2. The color cathode ray tube according to claim 1, wherein the edge is located below a perforated surface of the shadow mask. 3. A flat support portion and a flat weld portion are formed on the mask frame as a step, a shadow mask is stretched over the step, and the mask is welded to an outer edge of the flat surface of the weld portion. 3. The color cathode ray tube according to claim 2, wherein: 4. A shadow mask is stretched over an inclined surface formed on the mask frame, and an inner edge formed by the inclined surface and an inner surface of the mask frame is a support portion, and the inclined surface and the mask frame are separated from each other. The color cathode ray tube according to claim 2, wherein an outer edge formed by the outer surface is a welded portion. 5. A mask frame having a support portion formed of a flat surface and a welded portion formed of an inclined surface, a shadow mask extending from the flat surface to the inclined surface, and an outer surface formed by the inclined surface and an outer surface of the mask frame. 3. A color cathode ray tube according to claim 2, wherein a mask is welded to an edge of the color cathode ray tube. 6. A mask frame, wherein a first projection and a second projection lower than the first projection are formed, the first projection is a support portion, and the second projection is a welded portion. The color cathode ray tube according to claim 2, wherein 7. A method for manufacturing a color cathode ray tube comprising a step of stretching a shadow mask on a pair of opposed mask frames and welding and fixing the shadow mask with a roller seam electrode, wherein a peripheral portion of the shadow mask is formed on the mask frame. A method for manufacturing a color cathode ray tube, wherein a shadow mask is welded to an edge at an inclined surface of a roller seam electrode in contact with the edge. 8. The color cathode ray according to claim 7, wherein the gradient of the inclined surface of the roller seam electrode is larger than the gradient of the shadow mask between the mask support and the edge formed on the mask frame. Pipe manufacturing method.