JP2002008563A - Color cathode ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color cathode ray tube with a shadow mask protected from a deterioration of mechanical strength, with improved visibility. SOLUTION: Inner face of a panel fulfils at least one relation of either ZPH/ LPH<=0.050, or ZPV/LPV<=0.050, where; the length from the center of effective area to the edge in long axis direction is LPH, and the same in the short axis direction is LPV, and the subsiding amount of the center of the effective area in tube axis direction at long axis end is ZPH, and the same at short axis end is ZPV. At least, either long sides or short sides of mask face is formed into a curved line with a center part distending outside, and fulfils at least one relation of either YML/LML<=0.015, or XMS/LMS<=0.015, where; the distance from short axis of the effective area to diagonal end is LML, the distance from long axis to diagonal end is LMS, the subsiding amount from a point on short axis of long side to diagonal axis end in the direction parallel to short axis is YML, and the subsiding amount from a point on long axis of short side to diagonal axis end in the direction parallel to long axis X is XMS.

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 including a panel having a substantially flat outer surface and a shadow mask.

[0002]

2. Description of the Related Art In general, a color cathode ray tube includes a vacuum envelope having a substantially rectangular panel and a funnel. The panel has an effective portion formed of a curved surface and a skirt erected on the periphery of the effective portion, and the funnel is joined to the skirt. A phosphor screen having a black non-light-emitting material layer and three-color phosphor layers emitting blue, green, and red light provided on the inner surface of the panel effective portion so as to be embedded in gaps between the black non-light-emitting material layers. Are formed. A substantially rectangular shadow mask is provided inside the panel, and faces the phosphor screen with a gap.

On the other hand, an electron gun that emits three electron beams is arranged in the neck of the funnel. According to the color cathode ray tube, the three electron beams emitted from the electron gun are deflected by a magnetic field generated by a deflection yoke mounted outside the funnel, and horizontally and vertically scan the phosphor screen through a shadow mask. Thus, a color image is displayed.

The shadow mask includes a mask body having a substantially rectangular effective surface and a skirt extending from the periphery of the effective surface, and a rectangular mask frame fixed to the skirt of the mask body. ing. A large number of electron beam passage holes are formed on the effective surface of the mask body, and these electron beam passage holes separate three electron beams emitted from the electron gun into three color phosphor layers. The shadow mask is, for example, by engaging a holder attached to a corner of the mask frame with a stud pin provided at a corner of the skirt of the panel.
Supported inside the panel.

In such a color cathode ray tube, in order to display a color image without color shift on the phosphor screen, the three electron beams passing through the electron beam passage holes of the shadow mask are used as target three color fluorescent lamps. You need to land properly on the body layer. For this purpose, it is necessary to properly maintain the distance (q value) between the inner surface of the effective portion of the panel and the effective surface of the mask body.

In recent years, color cathode ray tubes have been put to practical use in which the curvature of the outer surface of the effective portion of the panel is reduced to a shape close to a flat surface for the purpose of improving visibility. In such a color cathode ray tube, if the curvature of the inner surface of the effective portion of the panel is large, the thickness difference between the center of the effective portion and the peripheral portion becomes large,
This poses a problem from visibility. Therefore, it is necessary to reduce the curvature of the inner surface of the effective portion corresponding to the shape of the outer surface of the effective portion. Furthermore, in order to secure the q value necessary for obtaining an appropriate beam landing, the effective surface of the mask body facing the phosphor screen also needs to be a curved surface having a small curvature that matches the inner surface shape of the effective portion of the panel. .

[0007]

However, when the curvature of the effective surface of the mask body becomes small, the mechanical strength of the mask body deteriorates, and the shadow mask is easily deformed in the manufacturing process of the color cathode ray tube. Also, the shadow mask is
After becoming a finished product, it is easily deformed by shock or vibration applied during transportation. Further, when the color cathode ray tube is incorporated in a television set, the shadow mask resonates with the sound from the speaker, and the color purity tends to deteriorate.

Conversely, if the curvature of the effective surface is increased in order to avoid deterioration of the mechanical strength of the mask body, it is necessary to increase the curvature of the inner surface of the effective portion of the panel in accordance with the curvature of the effective surface. In this case, the viewing angle is degraded, the displayed image is distorted, and the reflected image on the inner surface of the effective portion is easily seen, so that the visibility is deteriorated. Also, the brightness at the periphery of the screen is deteriorated, and the uniformity of the image is impaired.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to provide a color cathode ray tube in which the mechanical strength of a shadow mask is prevented from deteriorating and visibility is improved. It is in.

In order to achieve the above object, a color cathode ray tube according to the present invention has a substantially flat outer surface, an inner surface on which a phosphor screen is formed, a long axis and a short axis perpendicular to the tube axis and perpendicular to each other. A vacuum envelope having a substantially rectangular panel having a shaft, a shadow mask provided in the vacuum envelope facing the phosphor screen, and a shadow mask provided in the vacuum envelope. An electron gun for irradiating the phosphor screen with an electron beam through the shadow mask, wherein the shadow mask faces the phosphor screen and has an effective number of electron beam passage holes formed therein. A mask body having a substantially rectangular mask surface having a portion and a skirt portion extending along the periphery of the mask surface; and a substantially rectangular shape attached to the skirt portion of the mask body. And it includes a mask frame, a.

The inner surface of the panel has an effective area having a curvature, and the distance from the center of the effective area to the end of the effective area is defined by:
LPH in the long axis direction, LPV in the short axis direction, and the drop amount along the tube axis direction with respect to the center of the effective area,
Assuming ZPH at the long axis end and ZPV at the short axis end of the effective area,
The inner surface of the panel is formed so as to satisfy at least one of ZPH / LPH ≦ 0.050 or ZPV / LPV ≦ 0.050, and the mask surface has a pair of long sides located on both sides of the long axis. A pair of short sides located on both sides of the short axis, a distance from the short axis of the effective portion of the mask surface to the diagonal end is LML, a distance from the long axis of the effective portion to the diagonal end is LMS, The amount of drop along a direction parallel to the short axis from the point on the short axis of the long side of the mask surface to the end of the diagonal axis is YML, and the drop amount from the point on the long axis of the short side of the mask surface to the end of the diagonal axis. Assuming that the drop amount along the direction parallel to the major axis X is XMS, at least one of each long side and each short side is formed into a curve whose central portion protrudes outward, and YML / LM
L ≦ 0.015 or XMS / LMS ≦ 0.
015 is satisfied.

Further, a color cathode ray tube according to the present invention comprises:
A vacuum envelope having a substantially rectangular panel having a substantially flat outer surface, and an inner surface on which the phosphor screen is formed, and a long axis and a short axis orthogonal to the tube axis and orthogonal to each other; A shadow mask provided in the vacuum envelope facing the phosphor screen, and an electron provided in the vacuum envelope and irradiating the phosphor screen with an electron beam via the shadow mask. Wherein the shadow mask is opposed to the phosphor screen and extends along a substantially rectangular mask surface having an effective portion formed with a plurality of electron beam passage holes, and a peripheral edge of the mask surface. A mask body having a skirt portion, and a substantially rectangular mask frame attached to the skirt portion of the mask body.

The inner surface of the panel has an effective area having a curvature, and the distance from the center of the effective area to the end of the effective area is defined by:
LPH in the long axis direction, LPV in the short axis direction, and the drop amount along the tube axis direction with respect to the center of the effective area,
Assuming ZPH at the long axis end and ZPV at the short axis end of the effective area,
The inner surface of the panel is formed so as to satisfy at least one of ZPH / LPH ≦ 0.050 or ZPV / LPV ≦ 0.050, and the mask frame includes a pair of long side walls located on both sides of the long axis; A pair of short side walls located on both sides of the short axis, and the distance from the short axis to the diagonal end of the effective portion of the mask surface is LFL, and the distance from the long axis to the diagonal end of the effective portion is LFS, the amount of dip along a direction parallel to the short axis from the point on the short axis of the long side wall to the end of the diagonal axis is YFL, and the long axis from the point on the long axis of the short side wall to the end of the diagonal axis. When the drop amount along the direction parallel to X is XFS, at least one of each of the long side walls and each of the short side walls is formed on a convex curved surface whose central portion protrudes outward, and YFL / LFL ≦ 0.015 or XFS
/LFS≦0.015.

Further, according to the color cathode ray tube of the present invention, the panel has a transmittance at the center of the effective portion of 40 to 40%.
When the thickness at the center of the effective portion is Tc and the thickness of the panel at the end of the effective diameter of the phosphor screen is Td, Td / Tc <2.5 is satisfied.

According to the color cathode ray tube configured as described above, the curvature of the outer surface of the effective portion of the panel is reduced to a shape close to a plane, and accordingly, even when the curvature of the effective surface of the mask body is reduced. In addition, it reduces the deformation of the mask body due to shocks and vibrations applied during the manufacturing process and transportation of products, and the resonance between the mask body and the sound from the speakers when incorporated into a TV set, and color purity caused by beam landing deviation. Can be provided, and a color cathode ray tube with good visibility can be provided.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a color cathode ray tube according to an embodiment of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, the color cathode ray tube has a vacuum envelope 7 having a panel 3 and a funnel 4. The panel 3 has a substantially rectangular effective portion 1 and a skirt portion 2 erected along the periphery of the effective portion. The effective portion 1 has an outer surface formed of a flat surface or a curved surface having a slight curvature, and an inner surface formed of a curved surface described later. And
The funnel 4 is joined to the skirt 2. On the inner surface of the effective portion 1 of the panel 3, a black non-light-emitting material layer and blue formed so as to be embedded in the gaps between the black non-light-emitting material layers,
A phosphor screen 5 having a three-color phosphor layer that emits green and red light is provided. A substantially rectangular shadow mask 6 is disposed inside the panel 1 so as to face the phosphor screen 5 with a gap therebetween.

The panel 3 and the shadow mask 6
Has a major axis X (horizontal axis) orthogonal to the tube axis Z, and a minor axis Y (vertical axis) orthogonal to the tube axis Z and the major axis X.

An electron gun 7 for emitting three electron beams 9B, 9G, 9R is provided in the neck 8 of the funnel 4. Then, according to the color cathode ray tube, the three electron beams 9B, 9G, 9R emitted from the electron gun 7 are deflected by the magnetic field generated by the deflection yoke 12 mounted outside the funnel 4 and passed through the shadow mask 6. A color image is displayed by scanning the phosphor screen 5 horizontally and vertically.

As shown in FIG. 2, in the present embodiment, the inner surface 33 of the effective portion 1 of the panel 3 has a curvature, and the distance from the center of the effective region to the end of the effective region is LP in the long axis X direction.
H, LPV in the short axis Y direction, and the drop amount along the tube axis Z direction with respect to the center, ZP at the long axis end of the effective area.
H, ZPH at the short end, ZPH / LPH ≦ 0.
050 or ZPV / LPV ≦ 0.050.

Preferably, the transmittance at the center of the effective portion of the panel 3 is 40 to 60%, and the thickness at the center of the effective portion 1 is T.
c, when the thickness at the effective diameter end of the phosphor screen 5 is Td, these Tc and Td are Td / Tc <2.5.
The relationship is set.

As shown in FIG. 1 and FIGS. 3 (a) to 3 (c), the shadow mask 6 includes a mask body 15 and a mask frame 17 provided on the periphery of the mask body. The mask main body 15 has a mask surface 13 and a skirt portion 14 provided along the periphery of the mask surface. The mask surface 13 has a large number of electron beam passage holes 11.
It has a substantially rectangular effective portion 20 formed and a non-porous portion 22 located around the effective portion, and is formed in a curved surface facing the surface phosphor screen 5 and corresponding to the inner surface of the effective portion 1 of the panel 3. The electron beam passage holes 11 are provided for the three electron beams 9B, 9G,
Sort 9R. The mask frame 17 is formed in a substantially rectangular shape, and is fixed to the skirt portion 14 of the mask body 15.

The shadow mask 6 is supported inside the panel 3 by engaging an elastic support 18 attached to the mask frame 17 with a stud pin 19 provided on the skirt 2 of the panel 3. .

The mask surface 13 of the mask body 15 is
It has a pair of long sides located on both sides of the long axis X and a pair of short sides located on both sides of the short axis Y.
Has a pair of long side walls 14 a each extending along the long side of the mask surface 13 and a pair of short side walls 14 b each extending along the short side of the effective surface 13. Further, the mask frame 17 is formed on the long side wall 1 of the skirt portion 14 respectively.
4a, and a pair of long side walls 17b provided outside the long side wall 14b of the skirt portion 14, respectively.

In this embodiment, a pair of long sides of the mask surface 13 and a pair of long side walls 14 of the skirt portion 14 are used.
a and a pair of long side walls 17a of the mask frame 17,
Each is formed in a convex curved surface shape whose center projects outward. Similarly, the pair of short side walls 14b of the mask surface 13 and the short side walls 17b of the mask frame 17 are each formed in a convex curved shape whose center projects outward.

More specifically, each long side of the mask surface 13 and the long side wall 14a of the skirt portion 14 have a curvature from a point on the short axis Y toward the corner.
Each of the short sides and the short side wall 14b of the skirt portion 14 have a curvature from a point on the long axis X toward the corner, and are formed in a convex shape satisfying the following relationship. YML / LM
L ≦ 0.015 XMS / LMS ≦ 0.015 where LML is the distance from the short axis Y of the effective part 20 to the diagonal end, LMS is the distance from the long axis X of the effective part 20 to the diagonal end, YML indicates each long side of the mask surface 13 and the skirt portion 1
4, the amount of depression along a direction parallel to the short axis Y from the point on the short axis Y of the long side wall 14 a to the end of the diagonal axis, XMS is the short side of the mask surface 13 and the short side wall 14 b of the skirt portion 14. The drop amount along a direction parallel to the long axis X from a point on the long axis X to the end of the diagonal axis is shown.

The long side wall 17a of the mask frame 17
Has a curvature from a point on the short axis Y toward a corner, and further, the short side wall 17b of the mask frame 17 has a curvature from a point on the long axis X toward the corner. It is formed in a convex curved shape satisfying the relationship. YFL / LFL ≤
0.015 XFS / LFS ≦ 0.015 where
LFL is the distance from the minor axis Y of the effective part 20 to the diagonal axis end, LFS is the distance from the major axis X of the effective part 20 to the diagonal axis end, and YFL is the point on the minor axis Y of the long side wall 17a. The amount of drop along the direction parallel to the short axis Y to the diagonal axis end, XFS
Indicates the amount of drop along a direction parallel to the long axis X from a point on the long axis X of the short side wall 17b to the end of the diagonal axis.

According to the color cathode ray tube provided with the panel 3 and the shadow mask 6 constructed as described above, the curvature of the outer surface of the effective portion 3 of the panel 1 is reduced and the shape of the panel near the plane is improved for the purpose of improving visibility. In addition, even when the curvature of the inner surface of the effective portion and the mask surface 13 of the shadow mask 6 are reduced, deformation of the mask body due to shock or vibration applied during the manufacturing process of the color cathode ray tube or during transportation of the product can be prevented. When incorporated in a television set, degradation of color purity caused by beam landing deviation due to resonance with sound from a speaker can be reduced, and visibility can be improved.

Hereinafter, the color cathode ray tube according to the present embodiment is manufactured by using a panel having an effective diagonal diameter of 60 cm and an aspect ratio of 4:
3. A case where the present invention is applied to a substantially flat color cathode ray tube in which the radius of curvature of the outer surface of the effective portion of the panel is 10 m and the inner surface of the effective portion has a curved surface having a slight curvature.

As described above, in the shadow mask 6 combined with a flat panel having the outer surface of the effective portion 1 of the panel 3 having a curvature radius of 10 m, the long side of the mask body 15, the long side wall 14a of the skirt portion 14, and the mask frame. The long side walls 17a of each of the projections 17 are formed in a convex shape having a curvature projecting outward at the center, and the drop rates thereof are defined as YML / LML and YF.
L / LFL.

The short side of the mask body 15, the short side wall 14b of the skirt portion 14, and the short side wall 17 of the mask frame 17
b is formed in a convex shape having a curvature in which the center protrudes outward, and the falling ratio is represented by XMS / LMS and XFS / L.
FS.

In this case, these drop rates are set as follows. YML / LML = YFL / LFL = 0.022 XMS / LMS = XFS / LFS = 0.031 When the long side and the short side of the mask body 15 are formed in the above-described convex shape, the mask surface 13 is formed. Even if the shadow mask has a small curvature, its strength can be increased to prevent deformation of the mask surface. Therefore, the shadow mask is prevented from being deformed during the color cathode ray tube manufacturing process or during product transportation, and when incorporated into a television set, resonance between the shadow mask and the sound from the speaker is reduced, and the color based on the beam landing deviation is reduced. Deterioration of purity can be reduced.

That is, when an external impact is applied to the mask body 15 alone, as shown in FIG. 4A, the long side walls 14a 'and 14b' of the skirt portion have a curvature of almost zero, that is, a conventional dip rate of zero. In the mask body 15a, as shown by the broken lines, the long side walls 14a ', 14b' of the skirt portion.
Is greatly displaced, and accordingly, the mask surface 13a is greatly deformed.

On the other hand, as shown in FIG.
Like the mask body 15 according to the present embodiment, the long side and the short side of the mask surface 13 and the long side wall 14 of the skirt portion 14
When the a and short side walls 14b are formed into a convex curved surface having the above-described drop rate, the displacement of the long side wall 14a and the short side wall 14b is reduced as shown by the broken line, and the deformation of the mask surface 13 is also reduced accordingly. You. Therefore, it is possible to suppress the deformation process of the mask main body 15 after the manufacturing process of the color cathode ray tube or the finished product, and to reduce the deterioration of the color purity due to the deviation of the beam landing with respect to the three-color phosphor layer.

Further, the mask surface 13a of the conventional mask main body 15a and the mask main body 15 according to the present embodiment.
When the same load is applied to the mask surface 13 of FIG.
(Embodiment) As shown by a curve B (conventional), in the mask body according to the present embodiment, the amount of displacement on the long axis X can be reduced as compared with the conventional mask body.
In particular, according to the present embodiment, the displacement amount of the mask surface can be significantly reduced in the middle portion of the long axis where the displacement amount is the largest and the color purity is likely to deteriorate.

Similarly, the mask surface 13a of the conventional mask main body 15a and the mask main body 1 according to the present embodiment.
In the case where the same load is applied to the mask surface 13 of FIG. 5, the mask body according to the present embodiment is different from the conventional mask body as shown by a curve A (this embodiment) and a curve B (conventional) in FIG. In comparison, the displacement amount on the short axis Y can be reduced. In particular, according to the present embodiment, the displacement amount of the mask surface can be significantly reduced at the short axis intermediate portion where the displacement amount is the largest and the color purity is likely to deteriorate.

By reducing the deformation of the mask body in this way, it is possible to reduce the landing deviation of the electron beam with respect to the phosphor layer of the phosphor screen and to effectively prevent the color purity from deteriorating.

With the improvement of the mechanical strength of the mask body 15, as shown in FIG.
Depression rate ZPH / LP at the long axis end of the effective area on the inner surface
H is 0.026, the drop rate Z at the short axis end of the effective area
PV / LPV can be set to 0.044. Thereby, the viewing angle in the long axis X direction of panel 3 can be increased. In addition, reflection of external light from a fluorescent lamp or the like around the panel, which is affected by the drop rate on the short axis Y,
It can be greatly reduced.

Further, regarding such a panel 3, if the transmittance of the glass constituting the panel 3 is 50%, the thickness at the center of the effective portion is 12.0 mm, and the thickness at the peripheral portion is 25.0 mm, it is sufficient. The luminance can be made uniform from the center to the periphery of the phosphor screen 5 while maintaining a high contrast, and a visually excellent color cathode ray tube can be obtained.

Various panels having different ratios between the thickness Tc of the central portion of the panel 3 and the thickness Td of the peripheral portion were examined.
As a result, as shown in Table 1 below, in consideration of the relationship between black uniformity and luminance uniformity in each panel (パ ネ ル: good, Δ: somewhat good, ×: poor), the panel thicknesses Tc, Td
The ratio is preferably set to Td / Tc <2.5 in terms of viewing angle. In addition, the transmittance is 4
It turned out that it is good to set to 0-60%.

[0041]

[Table 1]

In the above-described embodiment, both the long side and the short side of the mask body 15 are formed so as to protrude outward, but at least the long side and the short side are formed. Even if one of them is formed in a convex shape, the mask surface 1
3 can be improved.

As shown in FIGS. 7A to 7C, according to the shadow mask 6 according to the second embodiment of the present invention, each long side of the mask surface 13 and the skirt 1
4 is formed in a straight line and a plane, and each short side of the mask surface 13 and each short side wall 14 of the skirt portion 14 are formed.
Only b has a convex shape with its center protruding outward. Similarly, the mask frame 17 also has a long side wall 1.
7a is formed in a plane, and the short side wall 17b is formed in a convex curved surface whose center protrudes outward.

The other structure is the same as that of the first embodiment described above, and the same portions are denoted by the same reference characters and will not be described in detail.

In such a mask body 15, when the falling ratio (XMS / LMS) of the short side of the mask surface 13 and the short side wall 14b of the skirt portion 14 is set to 0.020, the mask surface 13 has its own weight due to its own weight. The relationship between the drop rate on the long axis X and the amount of displacement of the curved surface at the middle portion on the long axis is as shown by a curve 26 in FIG. As can be seen from this figure, the deformation amount of the effective surface increases as the drop rate of the mask surface 13 decreases. Although FIG. 8A shows the drop rate, the relationship with the change in the average curvature is as shown in FIG. 8B, and the amount of deformation draws a similar curve 26 '.

When the mask body 15 has a drop rate of 0.043 on the long axis X of the mask surface 13, the curvature of the short side wall 14 b of the skirt portion 14 and the middle portion on the long axis X of the mask surface are determined. The relationship with the amount of displacement of the curved surface is as shown by a curve 27 in FIG. As can be seen from FIG.
By setting the drop ratio of 4b to 0.015 or more, the displacement of the curved surface of the mask effective surface 13 can be suppressed, and the deterioration of color purity can be effectively reduced.

The shadow mask 6 according to the second embodiment
Although the long side of the mask surface 13 is straight, the long side wall 14a of the skirt portion 14 is a flat surface, and the short side of the mask surface and the short side wall 14b of the skirt portion are convexly curved with the center protruding outward. The long side of the mask surface 13 and the long side wall of the skirt may be formed in a convex shape with the central portion protruding outward, and the short side of the mask surface and the short side wall of the skirt may be straight and flat. Also in this case, the same effect as in the above-described second embodiment can be obtained as shown by the curve 28 in FIG. 10 showing the relationship between the curvature of the long side wall and the amount of curved surface displacement of the mask surface.

Therefore, even in a shadow mask in which only one of the long side and the short side of the mask body 15 is convexly curved, by appropriately setting the curvature, the curved surface displacement of the mask surface having a small curvature can be reduced. It is possible to effectively suppress the deterioration of the color purity by suppressing the color purity.

Also, corresponding to the mask body 15 described above, the drop rate (LP) on the short axis Y of the inner surface of the effective portion 1 of the panel 3
As a result of setting (V / ZPV) to 0.039, reflection of external light on the inner surface of the effective portion 1 could be made less visible.

In a state where the distance from the screen to the viewer, which is a general television viewing condition, is set to 2 m, the position from the center of the screen to the fluorescent lamp is set to 3 m in the horizontal direction and 1.5 m in the height direction, the panel 3 When the external light reflection on the inner surface of the effective portion 1 was examined, the curvature of the inner surface of the effective portion 1 of the panel 3 and the position of the reflected image of the fluorescent lamp (the distance from the center of the screen along the short axis Y) to the eye were observed. The relationship was as shown by a curve 30 shown in FIG.

In this case, as shown in FIG.
The reflected image 32 of the fluorescent light projected on the outside of the effective diameter Ve in the short axis Y direction of the screen if the drop rate is about 0.044 or less even if the inner surface of the effective portion 1 of the panel 3 has a curvature. Therefore, the incidence on the eyes is reduced or eliminated.

It is to be noted that the reflection of external light on the screen becomes more severe when the effective diameter of the screen is further increased. However, the curvature of the inner surface of the effective portion 1 of the panel 3 is small, and the drop rate is 0.044. If less than the degree, eye fatigue due to reflection of external light is greatly reduced.

In the first and second embodiments described above, the mask frame 17 of the shadow mask 6 is shaped to match the skirt portion 14 of the mask body 15,
The long side wall 14a and the short side wall 14b of the scard part may be formed in a planar shape, respectively.

As shown in FIGS. 13 (a) to 13 (c), according to the shadow mask 6 according to the third embodiment of the present invention, the long side and the short side of the mask surface 13 and the skirt 14 The long side wall 14a and the short side wall 14b are each formed in a convex shape with a central portion protruding outward. On the other hand, the long side wall 17 of the mask frame 17
a and the short side wall 17b are both formed linearly. The mask body 15 is fixed to the mask frame 17 at the center of each long side wall 14a, the center of each short side wall 14b, and each corner of the skirt portion 14 of the skirt portion 14.

The other structure is the same as that of the above-described first embodiment, and the same portions are denoted by the same reference characters and will not be described in detail. Even when the shadow mask 6 configured as described above is used, at least one of the long side and the short side of the mask main body 15 has a curvature whose central portion is outwardly convex, and the drop ratio is 0.044. With the above, a shadow mask having the same functions and effects as those of the above-described embodiment can be obtained. Therefore, it is possible to suppress the displacement of the curved surface of the mask surface 13 and effectively reduce the deterioration of the color purity.

In recent years, in order to reduce the weight of the shadow mask, the thickness of the mask frame is reduced, and in order to compensate for the resulting deterioration in mechanical strength, an elastic support is attached near the diagonal axis of the mask frame. There is much to support. The shadow mask 6 is added to such a shadow mask.
When is applied, a great effect can be obtained. For example, when a shock of about 10 G is applied to the mask frame 17 having a thickness of 0.5 mm, the deformation can be improved by about 20%. The present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the present invention.

[0057]

As described above, according to the present invention, even when the curvature of the outer surface of the effective portion of the panel is reduced to a shape close to a plane and the curvature of the effective surface of the mask body is reduced accordingly, It reduces the deformation of the mask body due to shocks and vibrations applied during the manufacturing process and during transportation of products, and the resonance between the mask body and the sound from the speakers when incorporated into the TV set, and the color purity due to beam landing deviation is reduced. Deterioration can be reduced, and a color cathode ray tube with good visibility can be provided.

[Brief description of the drawings]

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

FIG. 2 is a perspective view schematically showing an inner surface shape of the panel of the color cathode ray tube.

FIG. 3 is a plan view showing a shadow mask of the color cathode ray tube, a sectional view taken along a major axis X of the shadow mask, and a sectional view taken along a minor axis Y of the shadow mask.

FIG. 4 is a perspective view schematically showing a deformed state of a conventional shadow mask, and a perspective view schematically showing a deformed state of the shadow mask according to the present embodiment.

FIG. 5 shows a case where the same load is applied to the mask body of the shadow mask according to the related art and the shadow mask according to the present embodiment, respectively.
FIG. 5 is a diagram illustrating a relationship between a distance from a mask center along a long axis and a curved surface displacement amount of a mask surface.

FIG. 6 shows a case where the same load is applied to the mask body of the shadow mask according to the related art and the present embodiment, respectively.
FIG. 4 is a diagram illustrating a relationship between a distance from a mask center along a short axis and a curved surface displacement amount of a mask surface.

FIG. 7 is a plan view showing a shadow mask of a color cathode ray tube according to a second embodiment of the present invention, a cross-sectional view along a long axis X of the shadow mask, and a short axis Y of the shadow mask. Sectional view.

FIG. 8 is a diagram showing the relationship between the drop rate of the mask body on the mask surface long axis and the amount of displacement of the mask surface in the second embodiment, and the mask body in the second embodiment. The figure which shows the relationship between the average curvature of a mask on a long axis, and the curvature displacement of the mask surface.

FIG. 9 is a diagram showing a relationship between a drop ratio of a short side wall of a mask main body and a displacement amount of a curved surface of a mask surface in the second embodiment.

FIG. 10 is a diagram illustrating a relationship between a drop rate of a long side wall of a mask body and a curved surface displacement amount of a mask surface in the second embodiment.

FIG. 11 is a diagram showing a relationship between a drop rate of an inner surface of an effective portion of a panel and a reflected image of a fluorescent lamp shown on a screen in the second embodiment.

FIG. 12 is a diagram schematically showing a reflected image of a fluorescent lamp shown on a screen.

FIG. 13 is a plan view showing a shadow mask of a color cathode ray tube according to a third embodiment of the present invention, a sectional view taken along a long axis X of the shadow mask, and a sectional view taken along a short axis Y of the shadow mask. FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Effective part 3 ... Panel 4 ... Funnel 5 ... Phosphor screen 6 ... Shadow mask 7 ... Vacuum envelope 10 ... Electron gun 13 ... Mask surface 14a, 17a ... Long side wall 14b, 17b ... Short side wall 15 ... Mask body 16 … Mask frame

Continuation of the front page (72) Inventor Masayo Inoue 1-9-2, Hara-cho, Fukaya-shi, Saitama F-term in the Toshiba Fukaya factory (reference) 5C031 EE01 EE15 EH04 EH06 5C032 AA02 BB06 BB09

Claims (5)

[Claims] 1. A substantially rectangular panel having a substantially flat outer surface, an inner surface on which a phosphor screen is formed, and a long axis and a short axis that are orthogonal to the tube axis and orthogonal to each other. A vacuum envelope, a shadow mask provided in the vacuum envelope so as to face the phosphor screen, and an electron beam transmitted to the phosphor screen through the shadow mask provided in the vacuum envelope. An electron gun for irradiating a beam, wherein the shadow mask faces the phosphor screen and has a substantially rectangular mask surface having an effective portion formed with a plurality of electron beam passage holes, and a mask surface. A mask body having a skirt portion extending along a peripheral edge; and a substantially rectangular mask frame attached to the skirt portion of the mask body, wherein an inner surface of the panel has a curvature. It has an effective area, and the distance from the center of the effective area to the end of the effective area is LPH in the long axis direction, LPV in the short axis direction, and the drop amount along the tube axis direction with respect to the center of the effective area. Assuming that ZPH is at the long axis end and ZPV is at the short axis end of the region, the inner surface of the panel is: ZPH / LPH ≦ 0.050 or ZPV / L
The mask surface is formed so as to satisfy at least one of PV ≦ 0.050. The mask surface has a pair of long sides located on both sides of the long axis and a pair of short sides located on both sides of the short axis. And
The distance from the short axis of the effective portion of the mask surface to the diagonal end is LM
L, the distance from the long axis of the effective portion to the diagonal end is LMS, the dip amount along a direction parallel to the short axis from the point on the short axis of the long side of the mask surface to the end of the diagonal axis is YML, Assuming that the drop amount along a direction parallel to the long axis X from the point on the long axis of the short side of the surface to the end of the diagonal axis is XMS, at least one of each long side and each short side is located at the central portion thereof. Is formed in a curve protruding outward, and YML / LML ≦ 0.015 or XMS / L
A color cathode ray tube which satisfies at least one of the following relationships: MS ≦ 0.015. 2. The panel has a transmittance at the center of the effective portion of 40 to 60%, a thickness at the center of the effective portion is Tc, and a thickness of the panel at an effective diameter end of the phosphor screen is Td. 2. The color cathode ray tube according to claim 1, wherein the color cathode ray tube is formed so as to satisfy Td / Tc <2.5. 3. The mask frame has a pair of long side walls located on both sides of the long axis and a pair of short side walls located on both sides of the short axis. The distance from the axis to the diagonal end is L
FL, the distance from the long axis of the effective part to the diagonal end is LF
S, YFL is the drop amount along a direction parallel to the short axis from the point on the short axis of the long side wall to the end of the diagonal axis, and the long axis from the point on the long axis of the short side wall to the end of the diagonal axis. When the drop amount along the direction parallel to X is XFS, at least one of each of the long side walls and each of the short side walls is formed on a convex curved surface whose central portion protrudes outward, and YFL / LFL ≦ 0.015 or XFS / L
The color cathode ray tube according to claim 1, wherein at least one of FS ≦ 0.015 is satisfied. 4. A substantially rectangular panel having a substantially flat outer surface, an inner surface on which a phosphor screen is formed, and a long axis and a short axis orthogonal to the tube axis and orthogonal to each other. A vacuum envelope, a shadow mask provided in the vacuum envelope so as to face the phosphor screen, and an electron beam transmitted to the phosphor screen through the shadow mask provided in the vacuum envelope. An electron gun for irradiating a beam, wherein the shadow mask faces the phosphor screen and has a substantially rectangular mask surface having an effective portion formed with a plurality of electron beam passage holes, and a mask surface. A mask body having a skirt portion extending along a peripheral edge; and a substantially rectangular mask frame attached to the skirt portion of the mask body, wherein an inner surface of the panel has a curvature. It has an effective area, and the distance from the center of the effective area to the end of the effective area is LPH in the long axis direction, LPV in the short axis direction, and the drop amount along the tube axis direction with respect to the center of the effective area. Assuming that ZPH is at the long axis end and ZPV is at the short axis end of the region, the inner surface of the panel is: ZPH / LPH ≦ 0.050 or ZPV / L
The mask frame is formed so as to satisfy at least one of PV ≦ 0.050, and the mask frame has a pair of long side walls located on both sides of the long axis and a pair of short side walls located on both sides of the short axis. And the distance from the short axis of the effective portion of the mask surface to the diagonal end is L
FL, the distance from the long axis of the effective part to the diagonal end is LF
S, YFL is the drop amount along a direction parallel to the short axis from the point on the short axis of the long side wall to the end of the diagonal axis, and the long axis from the point on the long axis of the short side wall to the end of the diagonal axis. When the drop amount along the direction parallel to X is XFS, at least one of each of the long side walls and each of the short side walls is formed on a convex curved surface whose central portion protrudes outward, and YFL / LFL ≦ 0.015 or XFS / L
A color cathode ray tube which satisfies at least one relationship of FS ≦ 0.015. 5. The panel has a transmittance at the center of the effective portion of 40 to 60%, a thickness at the center of the effective portion is Tc, and a thickness of the panel at an effective diameter end of the phosphor screen is Td. 5. The color cathode ray tube according to claim 4, wherein the color cathode ray tube is formed so as to satisfy Td / Tc <2.5.