JP3471493B2 - Color cathode ray tube - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color cathode ray tube, and more particularly to a color cathode ray tube having a shadow mask unit having a rectangular mask frame and a shadow mask attached to the mask frame.

[0002]

2. Description of the Related Art A color cathode ray tube generally includes an envelope having a face panel having a phosphor screen formed on the inner surface thereof and a funnel connected to the face panel. The phosphor screen is composed of a plurality of phosphor layers that emit red, green, and blue, respectively, and an electron gun that emits a plurality of electron beams corresponding to the emission colors is arranged at the neck portion of the funnel. Further, between the electron gun and the phosphor screen, inside the face panel, there is a shadow having a color selecting function for color-selecting the electron beam emitted from the electron gun and impinging on the phosphor layer of a predetermined emission color. A mask unit is provided, and this unit is attached to the envelope via a holder.

The shadow mask unit comprises a shadow mask formed of a substantially rectangular thin plate and a rectangular mask frame to which the peripheral edge of the shadow mask is attached. A large number of electron beam apertures through which the electron beam passes are formed in the shadow mask.

In recent years, there has been an increasing demand for the flatness of the screen of a color cathode ray tube in terms of visibility. Further, higher resolution is required for color cathode ray tubes used for computer displays and the like.

In order to increase the resolution of the color cathode ray tube, it is necessary to reduce the aperture pitch of the shadow mask to achieve high definition, but since the apertures of the shadow mask are formed by etching, high definition is required. In order to achieve this, it is preferable that the mask material be thin. On the other hand, from the viewpoint of mechanical strength of the mask, it is desired that the mask has a large plate thickness, and there are contradictory requirements for the plate thickness of the mask material.

Further, the shadow mask is for selecting an electron beam so that the electron beam emitted from the electron gun is correctly landed on the phosphor layer of the phosphor screen, and the phosphor screen is scanned by the electron beam. In order to improve the quality of the image drawn in (1), the shadow mask must be aligned with the phosphor layer at a predetermined position.

However, the amount of the electron beam that reaches the phosphor screen through the electron beam aperture of the shadow mask is 20 to 3 of the total amount of the electron beam emitted from the electron gun.
It is about 0%, and most of the other electron beams collide with the shadow mask to heat the shadow mask and thermally expand the shadow mask. The thermal expansion of the shadow mask becomes significant when a high-intensity image is displayed on the entire screen or when a locally high-intensity image is displayed. Due to this thermal expansion, the alignment relationship of the shadow mask with respect to the phosphor layer shifts. , Deterioration of color purity occurs.

Therefore, in order to improve the mechanical strength of the shadow mask and prevent the deterioration of the color purity, a method of attaching a flat shadow mask having a relatively thin plate to the mask frame under tension is adopted. ing. Specifically, in a state where tension is applied to the shadow mask along the vertical direction, a method of welding a pair of long side portions extending in the horizontal direction to the mask frame among the side edges of the shadow mask,
Alternatively, a method is employed in which both the long side portion and the short side portion of the shadow mask are welded to the mask frame while tension is applied to the shadow mask in the horizontal and vertical directions.

However, when the shadow mask is fixed to the mask frame in a state where tension is applied to the shadow mask as described above, the following problems occur. That is, in the rectangular mask frame, the rigidity of the corner portion of the frame is significantly higher than the rigidity of the central portion of each frame side wall. Therefore, for example, in the manufacturing process of the cathode ray tube, when the shadow mask unit is passed through a high temperature furnace and heated and then cooled, there is a problem that wrinkles occur near the corners of the shadow mask.

The wrinkle generation mechanism of the shadow mask will be described below. When the shadow mask unit is hot, both the shadow mask and the mask frame are thermally expanded, but when the unit is cooled, the shadow mask with a small heat capacity cools and shrinks first.
The mask frame bends as it is pulled by the shadow mask. At this time, the bending amount of the mask frame is small near the frame corner having high rigidity, and the corner portion of the shadow mask fixed to this frame corner portion is stretched and plastically deformed. After that, when both the shadow mask and the mask frame cool, the plastically deformed portion of the shadow mask remains as a slack wrinkle. Therefore, the positional matching relationship between the corner portion of the shadow mask and the phosphor layer is displaced, and the color purity is deteriorated.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object thereof is to ensure the mechanical strength of a shadow mask and to prevent the generation of wrinkles in the shadow mask. To provide a tube.

[0012]

In order to achieve the above object, a color cathode ray tube according to the present invention comprises a face panel having a phosphor screen formed on an inner surface thereof and a phosphor screen disposed opposite to the phosphor screen. An electron gun that emits a plurality of electron beams toward the target and a mask unit that is provided between the face panel and the electron gun are provided.

The mask unit is formed of a substantially rectangular thin plate, is arranged to face the phosphor screen, and has a plurality of electron beam apertures through which the electron beam passes, and a shadow mask. And a mask frame that holds a shadow mask in a state where tension is applied.

The mask frame is fixed to a rectangular frame body having four continuous side walls and at least a pair of side edge portions of the shadow mask, which face each other, and extends at least along the side edge portions. A pair of mask fixing portions, wherein the pair of mask fixing portions extend in parallel with at least a pair of side walls of the frame body which face each other, and correspond to the long-side central portion of each mask fixing portion. The connecting portion is connected to the central portion in the longitudinal direction of the side wall.

According to the above structure, since each mask fixing portion is connected to the frame main body at the longitudinal middle portion, the influence of the corner having high rigidity of the rectangular frame main body is suppressed from being transmitted to the mask fixing portion. be able to. Therefore, the rigidity of each mask fixing portion can be made substantially uniform along the longitudinal direction thereof, and wrinkles caused by heating the shadow mask can be prevented.

Further, according to the color cathode ray tube of the present invention, the leading edge of the mask fixing portion can be formed in an arc shape, and the shadow mask can be held in a cylindrical shape under tension. At this time, since the mask frame is provided with a slit that partially separates the mask fixing portion and the frame body from each other, the tension applied to the shadow mask can be adjusted to suppress the phenomenon of depression of the mask central portion. . That is, by partially separating and separating each mask fixing part from the side wall of the corresponding frame body by the slit,
The influence of the corners of the frame body, which has high rigidity, is not directly transmitted to the mask fixing part. Therefore, the rigidity of each position along the longitudinal direction of each mask fixing portion is adjusted, and the tension acting on the shadow mask is adjusted to the relationship of tensions that do not cause the shadow mask to fall.

Further, according to the present invention, the mask frame for holding the shadow mask in tension is formed in a rectangular cylindrical shape having four continuous side walls and arranged substantially coaxially with the axis of the electron gun. Then, a first slit formed in each diagonal portion of the mask frame in parallel with the axis of the electron gun and extending from one axial end of the mask frame toward an axially intermediate portion, and an extension of each first slit. And a pair of second slits extending from the projecting end toward the central portions of the two adjacent side walls forming the diagonal portion. With such a configuration, the mask frame is formed by connecting the rectangular frame body having four continuous side walls and the corresponding side wall of the frame body partially by the first and second slits. The shadow mask is divided into four mask fixing parts that are separate from each other and
One side edge may be fixed to each of the mask fixing portions.

The tip of the mask fixing portion may be flat or arcuate, and when it is arcuate, the shadow mask can be held in a cylindrical shape. Further, the rigidity of the mask fixing portion may be adjusted by changing the width of the slit or the plate thickness of the mask fixing portion, or the rigidity may be adjusted by providing an overhanging portion on the mask fixing portion or providing a reinforcing member. Good.

[0019]

DETAILED DESCRIPTION OF THE INVENTION A color cathode ray tube according to an embodiment of the present invention will be described in detail below with reference to the drawings. As shown in FIG. 1, the color cathode ray tube according to this embodiment includes an envelope 10 made of glass. The envelope has a substantially rectangular face panel 12 and a skirt portion 13 connected to the face panel 12. And a funnel-shaped funnel 14 integrally joined to the skirt portion 13. On the inner surface of the face panel 12, there is formed a phosphor screen 16 in which phosphor dots emitting red, green and blue are regularly arranged. In the neck 17 of the funnel 14, red,
Three electron beams 18R, 18 corresponding to green and blue
An electron gun 11 that emits G and 18B is arranged. The electron gun 11 is arranged on the tube axis Z of the cathode ray tube.

Further, in the envelope 10, a substantially rectangular shadow mask 20 having a large number of electron beam apertures 19 regularly arranged is provided at a position closely facing the phosphor screen 16 at a predetermined interval. Are arranged. The shadow mask 20 has its periphery joined to the mask frame 30, and together with the mask frame 30, the mask unit 21.
Are configured. The mask unit 21 includes the mask holder 8 extending from the mask frame 30 and the skirt portion 13
It is arranged inside the face panel 12 by being fitted to the stud pin 7 fixed to.

A deflection yoke 15 is provided outside the funnel 14.
Is installed. The three electron beams 18R, 18G, and 18B emitted from the electron gun 11 are deflected by the deflection yoke 15.
Is deflected by a magnetic field generated from the
By performing vertical scanning, a color image is displayed on the face panel 12.

As shown in FIG. 2, the shadow mask 20
Is a flat and thin metal plate having a thin thickness, and has a center through which the tube axis Z passes, a pair of long sides parallel to the horizontal axis X, and a pair of short sides parallel to the vertical axis Y. is doing. Further, the shadow mask 20 has a substantially rectangular perforated portion 22 having a large number of electron beam apertures 19 through which the electron beam passes, and a non-perforated portion 24 located around the perforated portion 22. Have

The electron beam apertures 19 are each formed in a circular shape, as shown in FIG. It should be noted that each electron beam aperture 19 may be formed in a rectangular shape formed side by side in a predetermined direction, as shown in FIG.

As shown in FIG. 2, the mask frame 30 of the mask unit 21 is formed of a metal plate in the shape of a rectangular cylinder having four side walls, and is arranged coaxially with the tube axis Z. At each corner of the mask frame 30, a first slit 31 is formed parallel to the tube axis Z and extending from one end of the mask frame in the axial direction to almost the middle portion. Further, the mask frame 30 is formed with second slits 32 extending in the X direction and the Y direction from the extending ends of the respective first slits 31.

By forming the first and second slits, the mask frame 30 has a rectangular frame-shaped frame main body 37 having four continuous side walls 37a, 37b, 37c and 37d, and four of the frame main body 37. Four mask fixing parts 33, 3 extending from one side wall and independent of each other
4, 35, and 36 are configured. Frame body 37
A pair of side walls 37a, 37b facing each other extend in the X direction,
The other pair of side walls 37c and 37d that face each other extend in the Y direction.

The mask fixing portions 33 to 36 respectively extend in parallel with the corresponding side walls of the frame body 37, and the middle portion of each frame fixing portion in the long side direction is defined between the second slits 32. Via the portion 38, it is connected to the central portion of the corresponding side wall in the long side direction.

In this embodiment, the first and second slits 31 and 32 are formed with a constant width. The second slit 32 partially separates each side wall of the frame body 37 and the corresponding mask fixing portion, and the mask is obtained by adjusting the width, length, etc. of each second slit as described later. The rigidity of each part of the fixed part can be adjusted.

Further, the leading edges of the mask fixing portions 33 to 36 are formed in a flat linear shape. Then, in the shadow mask 20, the pair of long side side edge portions are welded and fixed to the tip edges of the mask fixing portions 33 and 34, and the pair of short side side edge portions are the tip ends of the mask fixing portions 35 and 36. It is welded and fixed to the edge. The shadow mask 20 is fixed to the mask fixing portions 33 to 36 in a state of being pulled in the X direction and the Y direction, that is, in a state of receiving a tension.

As a method of applying tension to the shadow mask 20, for example, as shown in FIG. 4, the mask frame 30 is pulled in a predetermined tension in the X and Y directions as shown by arrows. The tension is released after welding and fixing to the mask fixing portion of the mask fixing portion 33, 34, 35, 36 as shown in FIG.
In the state in which the connecting portion 38 is applied with a compressive force that does not cause plastic deformation, the side edges of the shadow mask 20 are welded and fixed to the corresponding mask fixing portions, and then the compressive force is released. Can be taken.

Mask unit 2 constructed as described above
The above-mentioned mask holder 8 for holding 1 in the envelope 10 is provided on the side walls 37a to 37d of the frame body 37, respectively.

Next, the rigidity of the mask frame 30 of the mask unit 21 configured as described above will be described. First, when a rectangular mask frame having no first and second slits 31 and 32 is considered, for example, both ends of the frame side wall on the long side, that is, the corners of the frame are the side walls of the short side. Since it is a support, the rigidity is higher than that of the central part of the frame side wall. Therefore, as shown in FIG. 6, when a uniform compressive force is applied to the side wall of the mask frame from the outside, the distortion due to the compressive force at both ends of the frame side wall on the long side is larger than that at the central part of the frame side wall. Get smaller.

On the other hand, the first slit 3 is formed on the mask frame.
When only one is formed, each of the four mask fixing portions 33 to 36 has its both ends separated and independent from the other mask fixing portions, but the corner portion of the frame body 37 is at the center of each frame side wall. The both ends of each mask fixing part have higher rigidity than the parts, and are connected to the frame main body corner parts having high rigidity. Therefore, both end portions of each mask fixing portion are affected by the corners of the frame body, and have higher rigidity than the central portion of the mask fixing portion. Therefore, the respective mask fixing portions 33, 34, 35, and 36 have a difference in rigidity at each position along the longitudinal direction, and both ends in the longitudinal direction have higher rigidity than the intermediate portion in the longitudinal direction.

On the other hand, as in this embodiment, by forming the second slits 32 extending from the first slits 31 toward the central portions of the frame side walls, the mask fixing portions, particularly the masks, are masked. Both ends of the fixed part can be separated from both ends of the corresponding side wall of the frame body 37,
It is possible to prevent variations in the rigidity of the frame body 37 from affecting the mask fixing portions. Particularly, in the present embodiment, the rigidity of each mask fixing portion is adjusted substantially along the longitudinal direction of the mask fixing portion by adjusting the length of each second slit 32, in other words, the width of the connecting portion 38. It becomes possible to make it uniform.

FIG. 7 shows each part of the mask fixing portion 33 on the long side when a uniform compressive force in the vertical direction (Y direction) is applied to the frame body 37 of the shadow mask unit for a 17-inch color cathode ray tube. The result of examining the strain by changing the length of the second slit 32 is shown. In FIG. 7, the horizontal axis represents each position along the long side of the mask fixing portion, and the strain is measured at intervals of about 30 mm. The total compression force is 44 kg.

In the conventional mask frame having no second slit, as shown by the characteristic line 41, the mask fixing portion 3
The rigidity of both end portions of No. 3 is about 10 times as large as that of the central portion (the amount of deflection is one tenth). On the other hand, when the length of the second slit 32 is increased, that is, when the length in the X-axis direction of FIG. 2 is increased, the difference in rigidity between the both end portions and the central portion of the mask fixing portion 33 decreases. The length of the second slit 32 is 11
When it was set to 5 mm, as shown by the characteristic line 43, the rigidity at the end portion and the central portion of the mask fixing portion 33 became substantially uniform. This rigidity distribution is not limited to a uniform distribution, but can be arbitrarily selected by changing the size, shape, frame shape, etc. of the first and second slits 31, 32.

As described above, since the rigidity of each of the mask fixing portions 33 to 36 is substantially uniform along the longitudinal direction of the mask fixing portion, the mask fixing portions 33 to 36 are fixed to the mask fixing portions 33 to 36 under tension. Shadow mask 20
It is possible to prevent wrinkles from occurring.

For example, consider a case where the mask unit 21 is once heated and then cooled by passing through a high temperature furnace in the manufacturing process of the color cathode ray tube. First, as shown in FIG. 8A, when the temperature is high, the shadow mask 20
Also, both the mask frame 30 and the mask frame 30 thermally expand, and during cooling, the shadow mask 20 first cools and shrinks, and a force acts in the direction of compressing the mask frame. At this time, as shown in FIG. 8B, since the mask fixing portions 33, 34, 35, and 36 have uniform rigidity, the mask fixing portions 33, 34, 35, 36 have a uniform gap. 34, 35, 3
The compression force 6 is uniformly generated by the force from the shadow mask 20 over its entire length. Therefore, the shadow mask 20 is not locally stretched when it cools and shrinks, and local plastic deformation does not occur. Therefore, even when both the shadow mask 20 and the mask frame 30 are sufficiently cooled, as shown in FIG.
As shown in (c), it is possible to hold the shadow mask 20 in a state in which a predetermined tension is applied to the shadow mask 20 without wrinkling.

Further, as shown in FIG. 2, since the mask frame 30 is basically rectangular, it can be manufactured by inexpensive press working. That is, each mask fixing portion 33,
The 34, 35, 36 and the frame main body 37 can be integrally formed from a single plate material by pressing. In particular,
In the case of the dot type shadow mask 20 having the circular electron beam apertures 19, the Young's modulus is 1 / thicker than that of the shadow mask having the elongated slit-shaped electron beam apertures.
It is as small as 3 to 1/5 and the required tension is also small. Therefore, it is possible to obtain a mask unit that is sufficiently practical even with the strength of the mask frame formed by pressing.

For example, in an ultra-thin dot type shadow mask having a thickness of about 50 μm, the total tension applied to the mask frame is about 40 kg or less. Therefore, by providing bending reinforcing portions at various places in the mask frame, sufficient strength can be obtained even with a mask frame manufactured by pressing a plate material having a thickness of less than 2 mm, and the manufacturing cost can be reduced. Further, since the mask frame manufactured from a relatively thin plate material is light and has a small heat capacity, the frame cooling rate is increased and the influence of the temperature difference between the shadow mask and the mask frame is reduced.

In the first embodiment, the shadow mask is fixed to the mask frame 30 in a state where tension is applied to the shadow mask 20 in both the X direction and the Y direction. The direction of movement may be one of the X direction and the Y direction.

FIG. 9 shows, for example, that the shadow mask 20 has Y
The mask frame 30 used when applying a tension only to a direction is shown. According to the second embodiment, in the mask frame 30, the pair of mask fixing portions to which the short side edges of the shadow mask 20 are fixed are omitted, and the mask frame 30 includes the frame body 37 and the long side. It has only the mask fixing parts 33 and 34 on the side.

Also in such a configuration, the mask fixing portions 33 and 34 are provided with the second slits 32 extending from both longitudinal end portions of the mask fixing portions toward the central portion, thereby forming the mask fixing portions. The side walls 37a and 37b of the frame main body 37 can be partially separated to set the rigidity of each position of the mask fixing portion to be substantially uniform.

In the second embodiment, as shown in FIG. 10, the side walls 37c and 37d of the frame body 37 are
You may provide the mask contact pieces 51 and 52 of the height substantially equal to the mask fixing parts 33 and 34. Mask contact pieces 51, 52
Suppresses the shake of the shadow mask by its tip contacting the side edge on the short side of the shadow mask which is weak against vibration. In particular, the vibration of the shadow mask can be more effectively reduced by bringing the side edge on the short side of the shadow mask into contact with the mask contact pieces 51, 52 via a spring member having a weak spring constant.

In each of the above-mentioned first and second embodiments, a flat shadow-shaped flat shadow mask is used. However, in the present invention, the shadow mask is a collar whose cylindrical shape is held in tension. It can also be applied to cathode ray tubes. When the present invention is applied to a color cathode ray tube having a cylindrical shadow mask, it is possible to prevent wrinkles from occurring in the shadow mask as in the above-mentioned embodiment, and as described later, a dot-type shadow mask has a cylindrical shape. It also solves the unique problems that may occur when maintaining tension.

FIG. 11 shows a mask frame 30 of a mask unit according to a third embodiment applied to a color cathode ray tube having a cylindrical shadow mask. The mask frame 30 is similar to the mask frame shown in FIG. 9, and has a rectangular frame main body 37, a pair of mask fixing portions 33 and 34 to which the long side edges of the shadow mask 20 are fixed. Is equipped with. Each mask fixing portion has a second slit 32 extending from both ends toward the central portion, and the central portion is connected to the central portion of the corresponding side wall of the frame body 37 via the connecting portion 38. .

In addition, in the third embodiment, the mask fixing portions 33 and 3 to which the side edge portions of the shadow mask 20 are fixed.
The tip portion of No. 4 is formed in an arc shape having the highest central portion. When the shadow mask 20 is tension-maintained in an arc shape, the tension is basically applied only in the axial direction of the cylinder, that is, in the Y-axis direction, and the long side edge portion of the shadow mask 20 is fixed to the mask fixing portion 33. , 34, the shadow mask 20 is fixed to the mask frame.

Next, the operation of the mask unit 31 configured as described above will be described. As shown in FIG.
When a dot type shadow mask 20 having, for example, a circular electron beam opening is cylindrically tension-held in a conventional mask frame 30 in which the second slit is not provided between the mask fixing portion and the frame body, A drop Δz of the shadow mask 20 occurs at the central portion in the vertical axis (Y-axis) direction as shown in FIGS. 13 and 14. Note that FIG.
In FIG. 3, a curved line 61 represents the curved surface of the mask at the tip of the mask fixing portion 33, and a broken line 62 represents the curved surface of the shadow mask at the intermediate portion in the Y-axis direction.

As described above, the drop Δz is generated as shown in FIG. 14, when the tension T in the vertical direction is applied to the dot type shadow mask 20, it is proportional to the extension in the vertical direction (X This is because shrinkage occurs in the direction). Due to this horizontal contraction, a horizontal outward force Th appears on the shadow mask 20, and the tube axis direction component Tz of Th causes a drop in the central portion of the shadow mask.

This drop depends on the distribution of tension acting on the shadow mask 20 at each horizontal position. That is, as shown in FIG. 15A, when the relationship between the tension T1 acting on the central portion of the long side of the shadow mask 20 and the tension T2 acting on both ends of the long side in the horizontal direction is T1 <T2. , The outward force Th in the horizontal direction becomes large, and as a result, the depression of the central portion of the shadow mask becomes large as shown in FIG. On the other hand, FIG.
As shown in, when the tension distribution is T1> T2, Th
Becomes smaller, and as a result, as shown in FIG.
The depression of the central portion of the shadow mask is suppressed.

FIG. 17 shows the result of measuring the amount of depression on the vertical axis of the shadow mask when the distribution of tension acting on the long side of the shadow mask 20 was changed for a mask unit for a 17-inch color cathode ray tube. Shows. As can be seen from this figure, the relationship between the tension T1 at the horizontal center of the long side and the tension T2 at the horizontal end is T1 <T.
When the value is 2, the horizontal tension component Th at the central portion of the shadow mask becomes large, resulting in the characteristic line 71.
As shown in, the amount of depression of the shadow mask increases. When the tension relationship is T1 = T2, the drop of the shadow mask 20 is suppressed as shown by the characteristic line 72.

If the tension T2 at the horizontal end of the long side is smaller than the tension T1 at the central portion and T1> T2, then the horizontal tension Th at the vertical central portion of the shadow mask 20 is Th. Is smaller, and as shown by the characteristic line 73, it can be seen that the dip phenomenon is considerably suppressed. In the data of FIG. 17, the lengths of the mask fixing portions 33 and 34 of the mask frame in the X-axis direction are 330 mm, and the tip end portion where the side edges of the shadow mask are welded has a radius of curvature of 1100.
It is based on a mask unit that has an arc of mm.
Since the amount of depression of the shadow mask 20 depends only on the tension distribution, the amount of depression does not change even if the total tension is changed if the distribution is constant.

During operation of the color cathode ray tube, the shadow mask 20 is heated by the irradiation of the electron beam and causes thermal expansion. In the conventional mask frame having no second slit, when the shadow mask uniformly thermally expands due to the temperature rise during beam irradiation, the tension T2 of the shadow mask 20 at both ends of the highly rigid long side in the horizontal direction is increased. Markedly reduced. Therefore, the tension distribution during heating of the shadow mask is
Compared to the distribution before heating, it changes in the direction of T1> T2.
As a result, the amount of shadow mask drop is reduced, and the landing shift of the electron beam caused by this drop moves toward the center of the screen.

On the other hand, according to the mask frame 30 of the present embodiment shown in FIG. 11, since the second slit 32 is provided, the rigidity of the mask fixing portions 33 and 34 at each position is substantially uniform. Therefore, even if the shadow mask 20 is thermally expanded, the tension distribution does not change, and the landing characteristics of the electron beam do not deteriorate.

Further, in the present embodiment, even if the rigidity of the mask fixing portions 33 and 34 is not uniform so that the landing change does not occur, the beam landing change at the time of electron beam irradiation can be reduced. That is, the thermal expansion of the shadow mask 20 at the time of electron beam irradiation causes the landing change of the electron beam toward the outside of the screen by itself, but the length, width, etc. of the second slit 32 are changed to change the shadow mask heat. By adjusting the change in tension distribution of the shadow mask during expansion, it is possible to reduce the amount of depression of the shadow mask during thermal expansion of the shadow mask and reduce the change in landing.

In the above-mentioned first to third embodiments, each mask fixing portion is composed of a plate-shaped member having a constant thickness, and the second sidewall separates the side wall of the mask body from the mask fixing portion. Each of the slits is formed in a strip shape having a constant width, but the thickness of the mask fixing portion may be changed, or the width of the second slit may be changed, as in the embodiment described below. You may let me.

18 and 19 (a) to 19 (c)
Shows a fourth embodiment in which a mask unit 31 is constructed by fixing a flat rectangular shadow mask 20 to a mask frame 30 in a state where tension is applied along the Y direction. The mask frame 30 has a rectangular mask body 37.
And a pair of mask fixing portions 33 and 34 to which the long side edges of the shadow mask 20 are fixed by welding. These mask fixing portions include two opposing side walls 3 of the mask body.
7a and 37b are erected via a connecting portion 38.

In the fourth embodiment, each mask fixing portion 3
3, 34 are formed so that the plate thickness gradually increases from both ends in the longitudinal direction toward the central part, and each has a shape protruding in an arc shape in a direction away from the other mask fixing part. The side wall 37a of the frame body 37,
In 37b, the second slit 32 extending from both ends of each side wall toward the center is formed in a band shape having a uniform width.

The rest of the configuration is the same as that of the above-mentioned embodiment, and the same parts are designated by the same reference numerals and detailed description thereof will be omitted. In the fourth embodiment having the above configuration,
Each of the mask fixing portions 33 and 34 has the thickest central portion and is gradually thinned toward both end portions in the longitudinal direction. Therefore, each of the side walls of the mask main body 37 can have substantially uniform rigidity along the longitudinal direction even though the rigidity of both end portions is higher than that of the central portion thereof. Therefore, similarly to the above-described embodiment, it is possible to prevent the generation of wrinkles near the corners of the shadow mask 20 and provide a color cathode ray tube with high color purity.

FIG. 20 shows a fifth example for holding the shadow mask 20 in a state where tension is applied in the X and Y directions.
3 shows a mask frame 30 according to the embodiment of FIG. The mask frame 30 further includes a pair of mask fixing portions 35 for fixing the short side edges of the shadow mask 20 by welding to the mask frame according to the fourth embodiment.
Equipped with 36. Each of the mask fixing portions 35 and 36 is also configured such that the plate thickness gradually increases from both longitudinal end portions toward the central portion. The other structure is the same as that of the fourth embodiment.

Also in the fifth embodiment thus constructed, it is possible to obtain the same effects as the fourth embodiment. FIG. 21 shows a mask frame 30 according to a sixth embodiment, which holds the shadow mask 20 in a state where tension is applied in one direction, for example, the Y direction. According to the sixth embodiment, the mask frame 30 includes the shadow mask 2
A pair of mask fixing portions 33 and 34, to which both side edges on the long side of 0 are fixed by welding, are provided, and each mask fixing portion is formed to have a constant plate thickness. Further, according to this embodiment, each of the pair of second slits 32 extending from both ends of each side wall of the frame body 37 toward the central portion in the longitudinal direction is fixed to the mask from the vicinity of the connecting portion 38 of the mask fixing portion. The width is gradually increased toward the end of the portion in the longitudinal direction.

Also in the sixth embodiment having such a structure, the rigidity of each mask fixing portion is increased by gradually increasing the width of each second slit 32 toward the end of the mask fixing portion in the longitudinal direction. It can be made uniform along the direction, and the same effect as described above can be obtained.

FIG. 22 shows a seventh embodiment for holding the shadow mask 20 with tension applied in the X and Y directions.
3 shows a mask frame 30 according to the embodiment of FIG. The mask frame 30 further includes a pair of mask fixing portions 35 for welding and fixing both side edges on the short side of the shadow mask 20 to the mask frame according to the sixth embodiment.
Equipped with 36. Each of the mask fixing portions 35 and 36 is also partially separated from the side walls 37c and 37d of the frame body 37 by the pair of second slits 32, and is erected at the center of the corresponding side wall via the connecting portion 38. Has been done. Then, also in this embodiment, the mask fixing portion 3
Each of the reference numerals 5 and 36 is formed to have a constant plate thickness, and each second slit 32 has a width gradually increasing from the vicinity of the connecting portion 38 of the mask fixing portion toward the longitudinal end of the mask fixing portion. Has been formed.

Also in the seventh embodiment thus constructed, the same operational effect as that of the sixth embodiment can be obtained. In the fourth and sixth embodiments, the tip portion of each mask fixing portion to which the shadow mask is fixed has a flat shape, but the shape is not limited to this, as in the third embodiment shown in FIG. The tip end portion of the mask fixing portion may be formed in an arc shape to fix and hold the shadow mask in a curved state.

23 to 27 (b) show respective embodiments in which a mask fixing portion is provided with a projecting portion or a reinforcing member. According to the eighth embodiment shown in FIG. 23,
A pair of opposing side walls 37 of the rectangular frame body 37
A pair of mask fixing portions 33 and 34, to which the long side edges of the shadow mask 20 are fixed by welding, are connected to a and 37b via connecting portions 38, respectively. Each of the mask fixing portions 33 and 34 includes a side wall 37 a of the frame main body 37,
It is formed in a rectangular plate shape extending in parallel with 37 b, and both ends in the longitudinal direction except the connecting portion 38 are separated from the side wall of the frame body 37 by the pair of second slits 32.

Further, in this embodiment, the upper end portion or the tip end portion of each of the mask fixing portions 33 and 34 is bent at a substantially right angle toward the other mask fixing portion, and the elongated rectangular protruding portions 42 and 43 are formed. Are configured. Then, the shadow mask has a side edge portion on the long side thereof which is an overhanging portion 4.
2 and 43 are welded and fixed, respectively, and are supported by the mask frame 30 in a state in which tension in the Y direction is not allowed. In addition,
In the present embodiment, the same parts as those in the above-mentioned embodiments are designated by the same reference numerals, and detailed description thereof will be omitted.

According to the eighth embodiment having the above-mentioned structure, by providing the second slit 32, the rigidity of each mask fixing portion can be made substantially uniform along the longitudinal direction. Further, by providing the overhanging portions 42 and 43,
The rigidity of each mask fixing portion can be increased substantially uniformly over the entire length in the longitudinal direction. Therefore, it is possible to prevent the wrinkles of the shadow mask from being generated during the manufacture of the color cathode ray tube, and to prevent the deformation of the mask fixing portions 33 and 34 due to the tension of the shadow mask. As a result, it is possible to provide a color cathode ray tube that is less likely to cause deterioration in color purity.

In the eighth embodiment, the projecting portions 42 and 43 of the mask fixing portions 33 and 34 are arranged to extend at right angles to the mask fixing portions, but each projecting portion, for example, the projecting portion. 42 may extend downwardly at an acute angle as shown in FIG.
As shown in FIG. 4 (b), it may extend upward at an acute angle. Also in these cases, the same effect as that of the eighth embodiment can be obtained.

Further, the projecting portions 42 and 43 are not limited to the rectangular shape, and the tip end edge of the projecting portion is formed in an arc shape which is convex toward the other projecting portion as in the ninth embodiment shown in FIG. It may be formed as follows. In this case, the rigidity of the central portions of the mask fixing portions 33 and 34 can be particularly enhanced by the projecting portions 42 and 43, and the rigidity of the mask fixing portion can be made more uniform along the longitudinal direction.

According to the tenth embodiment shown in FIG. 26, the pair of mask fixing portions 33 and 34 are provided with overhanging portions 42 and 4.
Instead of 3, the elongated strip-shaped reinforcing members 45 and 46 are fixed by welding. The reinforcing members 45 and 46 have an L-shaped cross-sectional shape, and the mask fixing portions 33 and
It extends over the entire length of 34.

Also in the tenth embodiment constructed as described above, by providing the reinforcing members 45 and 46, the rigidity of each mask fixing portion can be increased substantially uniformly over the entire longitudinal direction. Therefore, it is possible to prevent the wrinkles of the shadow mask from being produced at the time of manufacturing the color cathode ray tube, and each mask fixing portion 3 due to the tension of the shadow mask.
The deformation of 3, 34 can be prevented. As a result, it is possible to provide a color cathode ray tube that is less likely to cause deterioration in color purity.

In the tenth embodiment, each of the reinforcing members 45 and 46 is formed to have an L-shaped cross section and has an extending portion that is perpendicular to the mask fixing portion. 27A, the reinforcing member 45 may have a configuration having an extending portion 45a extending upward at an acute angle as shown in FIG. 27A, or an extending portion extending downward at an acute angle as shown in FIG. 27B. You may have the protrusion part 45b. Also in these cases, the same effect as the tenth embodiment can be obtained.

25 to 27 (b),
The same reference numerals as those in the above-described embodiment indicate the same components, and detailed description thereof will be omitted. In the plurality of embodiments described above, the mask fixing portion and the frame body have a flat cross section. However, the structure of the mask fixing portion is not limited to the above embodiment, and the following structure is also possible. That is, as shown in FIG. 28, the frame body 3
The bent portions 81, 82, 83, 84 may be provided on the mask fixing portions 33, 34, 35, 36 and the like. When the bent portion is provided, the strength of the frame main body and the mask fixing portion can be improved. Therefore, the mask frame 3
0 can be made lighter and have a small heat capacity, and the cooling rate difference between the shadow mask and the mask frame in the high temperature furnace during the manufacturing process can be reduced.

Furthermore, changes in the plate thickness of the mask fixing portion, changes in the slit width, and the like in the above-described embodiments are merely examples, and may be appropriately adjusted so as to make the rigidity uniform.
Further, in the above embodiment, the mask frame 30 has been described as being integrally molded. However, after the frame body and the mask fixing portion are formed as separate members, they may be connected and integrated at the connecting portion. Good.

[0074]

As described above, according to the present invention,
It is possible to arbitrarily select the rigidity distribution at each position along the longitudinal direction of the mask fixing portion, and it is possible to suppress the generation of mask wrinkles during manufacturing. Further, it becomes possible to suppress the deterioration of the landing characteristics.

[Brief description of drawings]

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

FIG. 2 is an exploded perspective view of a mask unit of the color cathode ray tube.

3A and 3B are partially enlarged views showing a main part of a shadow mask, FIG. 3A is an enlarged plan view showing a part of a shadow mask having a circular electron beam aperture, and FIG. 3B is a rectangular electron beam. It is a top view which expands and shows a part of shadow mask which has an opening.

FIG. 4 is a plan view showing a method of pulling a shadow mask to apply tension.

FIG. 5 is a plan view showing a method of compressing the mask frame and applying tension to the shadow mask.

FIG. 6 is a plan view showing a state in which a compressive force is applied to a conventional mask frame.

FIG. 7 is a graph showing the presence / absence of a second slit in the mask frame, and the relationship between each position of the mask fixing portion and the distortion amount when the second slit length is changed.

FIG. 8 is a plan view showing a deformed state of the shadow mask and the mask frame when the mask unit is heated and then cooled.

FIG. 9 is a perspective view of a mask unit according to a second embodiment of the present invention.

FIG. 10 is a perspective view showing a modified example of the mask unit according to the second embodiment.

FIG. 11 is a perspective view of a mask unit according to a third embodiment of the present invention.

FIG. 12 is a perspective view showing a conventional mask unit having an arc-shaped mask fixing portion.

FIG. 13 is a side view of the conventional mask unit.

FIG. 14 is a plan view showing how a force is applied to a shadow mask in the conventional mask unit.

FIG. 15 is a diagram for explaining a case where the tension acting on both ends of the shadow mask is higher than the tension acting on the central portion of the shadow mask, FIG. 15A is a plan view of the shadow mask,
(B) is a side view of the mask unit.

FIG. 16 is a diagram illustrating a case where the tension acting on both ends of the shadow mask is smaller than the tension acting on the central portion of the shadow mask, FIG. 16A is a plan view of the shadow mask,
(B) is a side view of the mask unit.

FIG. 17 is a graph showing the relationship between the tension acting on each part of the shadow mask and the amount of depression at the center of the shadow mask.

FIG. 18 is a perspective view of a mask frame used in the mask unit according to the fourth embodiment of the present invention.

FIG. 19 shows the mask unit of the above embodiment, (a)
Is a plan view, (b) is a side view on the short side, and (c) is a side view on the long side.

FIG. 20 is a perspective view of a mask frame according to a fifth embodiment of the present invention.

FIG. 21 is a perspective view of a mask frame according to a sixth embodiment of the present invention.

FIG. 22 is a perspective view of a mask frame according to a seventh embodiment of the present invention.

FIG. 23 is a perspective view of a mask frame according to an eighth embodiment of the present invention.

FIGS. 24 (a) and 24 (b) are perspective views respectively showing a modified example of the projecting portion in the eighth embodiment.

FIG. 25 is a perspective view of a mask frame according to a ninth embodiment of the present invention.

FIG. 26 is a perspective view of a mask frame according to a tenth embodiment of the present invention.

27 (a) and 27 (b) are perspective views respectively showing modified examples of the projecting portion in the tenth embodiment.

FIG. 28 is a sectional view showing a part of a mask frame according to an eleventh embodiment of the present invention.

[Explanation of symbols]

20 ... Shadow mask 30 ... Mask frame 31 ... First slit 32 ... Second slit 33, 34, 35, 36 ... Mask fixing part 37 ... Frame body 37a, 37b, 37c, 37d ... Side wall of frame body 38 ... Connection part 42, 43 ... Overhanging part 45, 46 ... Reinforcing member

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-57-96448 (JP, A) JP-A-4-359840 (JP, A) JP-B-45-36255 (JP, B1) (58) Field (Int.Cl. ⁷ , DB name) H01J 29/07 H01J 9/14

Claims (15)

(57) [Claims] 1. A face panel having a phosphor screen formed on an inner surface thereof, an electron gun arranged to face the phosphor screen and emitting a plurality of electron beams toward the phosphor screen, the face panel and the electron gun. And a mask unit provided between the mask unit and the mask unit. The mask unit is formed of a substantially rectangular thin plate and is arranged so as to face the phosphor screen. A shadow mask having holes,
A color cathode ray tube comprising a mask frame holding a shadow mask in a state where tension is applied to the shadow mask, wherein the mask frame has a substantially rectangular frame body having four continuous side walls, and the shadow mask Of at least a pair of side edge portions facing each other, and at least a pair of mask fixing portions extending along the side edge portions, respectively, wherein the pair of mask fixing portions face each other of the frame body. A color cathode ray tube having at least a pair of side walls extending in parallel with each other and having a connecting portion connected to a longitudinal center portion of the side wall corresponding to a longitudinal center portion of each mask fixing portion. . 2. The color cathode ray tube according to claim 1, wherein each mask fixing portion has a flat tip portion, and a side edge portion of the shadow mask is fixed to the tip portion. 3. The mask fixing portion has an arc-shaped tip portion curved in a convex shape, and a side edge portion of the shadow mask is fixed to the tip portion.
The described color cathode ray tube. 4. The frame main body has a pair of slits extending from both ends of the side wall toward the center to separate the both ends of the side wall from the mask fixing part and defining the connecting part. The color cathode ray tube according to claim 1, which has. 5. The color cathode ray tube according to claim 4, wherein the slit has a constant width from an end portion of the side wall toward a central portion. 6. The color cathode ray tube according to claim 4, wherein the slit is formed so as to have a width gradually narrowed from an end portion of the side wall toward a central portion. 7. The color cathode ray tube according to claim 1, wherein each mask fixing portion is formed of a plate-shaped member having a constant thickness. 8. The color cathode ray tube according to claim 7, wherein each of the mask fixing portions has a projecting portion extending toward the other mask fixing portion. 9. The color cathode ray tube according to claim 8, wherein the projecting portion has an arc-shaped tip portion which is curved in a convex shape. 10. The color cathode ray tube according to claim 7, wherein the mask frame includes a reinforcing member fixed to the mask fixing portion. 11. The color cathode ray tube according to claim 10, wherein the reinforcing member is formed in an elongated strip shape and extends over substantially the entire length of the mask fixing portion. 12. The color cathode ray tube according to claim 1, wherein the mask fixing portion is formed so that the thickness gradually increases from both longitudinal end portions toward the central portion. 13. The mask frame has a pair of first mask fixing portions to which both long side edges of the shadow mask are fixed and both short side edges of the shadow mask. And a pair of second mask fixing portions, wherein the first mask fixing portion has a central portion in the longitudinal direction fixed to the central portions of a pair of side walls of the mask body facing each other via the connecting portion. , The second mask fixing portion,
2. The color cathode ray tube according to claim 1, wherein the center portion in the longitudinal direction is connected to the center portions of the other pair of side walls of the mask body which face each other via the connecting portion. 14. A face panel having a phosphor screen formed on an inner surface thereof, an electron gun arranged to face the phosphor screen and emitting a plurality of electron beams toward the phosphor screen, the face panel and the electron gun. And a mask unit provided between the mask unit and the mask unit. The mask unit is formed of a substantially rectangular thin plate and is arranged so as to face the phosphor screen. A shadow mask having holes,
A color cathode ray tube comprising a mask frame holding a shadow mask in a state where tension is applied to the shadow mask, wherein the mask frame has a substantially rectangular frame body having four continuous side walls, and the shadow mask A pair of mask fixing portions fixed to a pair of side edge portions facing each other and extending along the side edge portions, respectively. Each of the pair of side walls is provided upright on the side wall, and each of the pair of side walls has a pair of slits extending from both ends of the side wall toward the central portion, and the mask fixing portion is formed by the pair of slits at both ends of the side wall. A color cathode ray tube characterized in that it is separated from the part. 15. A face panel having a phosphor screen formed on an inner surface thereof, an electron gun arranged to face the phosphor screen and emitting a plurality of electron beams toward the phosphor screen, the face panel and the electron gun. And a mask unit provided between the mask unit and the mask unit. The mask unit is formed of a substantially rectangular thin plate and is arranged so as to face the phosphor screen. A shadow mask having holes,
In a color cathode ray tube comprising a shadow mask and a mask frame holding the shadow mask under tension, the mask frame has four continuous side walls and is substantially coaxial with the axis of the electron gun. The mask frame is formed in a rectangular tubular shape and is provided with a first slit formed in each diagonal portion in parallel with the axis and extending from one axial end of the mask frame toward an axial intermediate portion. A pair of second slits extending from the extending end of each first slit toward the central portions of two adjacent side walls forming the diagonal portion,
The mask frame includes a rectangular frame body having four continuous side walls and a part of the frame body connected to corresponding side walls of the frame body and separated from each other by the first and second slits. A color cathode ray tube, characterized in that the shadow mask is divided into four mask fixing portions, and four side edges of the shadow mask are fixed to the mask fixing portions, respectively.