JPH11339678A - Color picture tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of mislanding even when the ambient temperature is changed by welding the skirt section of a shadow mask main body and the side wall section of a frame at positions near the major axis between the diagonal axes and the major axis, and forming notches weakening the rigidity in the minor axis direction of the frame near the weld points. SOLUTION: A shadow mask main body 29 is made of a small-thermal expansion material such as invar having the thermal expansion coefficient of 1/2 or below that of iron, and a frame 31 is made of an iron material such as a cold rolled steel sheet. When notches 33 are formed on the short side wall sections 30 of the frame 31 near the weld points near the major axis between diagonal axes and the major axis and welded, the rigidity in the minor axis direction of the short side wall sections 30 near the weld points can be weakened. The minor axis direction component of elongation is absorbed by the deformation of the frame 31 near the weld points, and the deformation of the effective face 26 of the shadow mask main body 29 is prevented. When the ambient temperature is increased or decreased, the same effect is obtained, and the deterioration in color purity is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color picture tube, and more particularly to a color picture tube in which color purity is prevented from deteriorating due to environmental temperature.

[0002]

2. Description of the Related Art Generally, a color picture tube has an envelope comprising a substantially rectangular panel 1 and a funnel-shaped funnel 2, as shown in FIG. A phosphor screen 3 made of a layer is provided, and a substantially rectangular shadow mask 4 is arranged inside the phosphor screen 3 so as to face the phosphor screen 3. On the other hand, an electron gun 7 for emitting three electron beams 6B, 6G, 6R (only 6G is shown) is arranged in the neck 5 of the funnel 2. And
The three electron beams 6B, 6G,
6R is deflected by a deflecting device 8 mounted on the outside of the funnel 2, selected by a shadow mask 4, and horizontally and vertically scanned by the phosphor screen 3, so that a color image is displayed.

As shown in FIG. 5, the shadow mask 4 is provided with a large number of electron beam passage holes 11 on an effective surface 10 facing the phosphor screen, and a skirt portion 12 is provided around the effective surface 10. The shadow mask body 13 includes a substantially rectangular shadow mask body 13 and a substantially rectangular frame 15 having a side wall portion 14 welded to the skirt portion 12 of the shadow mask body 13.

In this shadow mask type color picture tube,
Of the three electron beams emitted from the electron gun 7, 30% or less of the three electron beams that enter the phosphor screen through the electron beam passage holes of the shadow mask, and the other electron beams pass through the shadow mask. Heat by impact.
Due to the resulting thermal expansion, the shadow mask undergoes a thermal deformation called doming, causing a mislanding in which the position of the electron beam striking the phosphor layer changes, thereby deteriorating the color purity.

In order to prevent the color purity from deteriorating due to the doming, the shadow mask body is made of amber (Fe-Ni).
Alloys) have been put to practical use. When the shadow mask body is made of a low thermal expansion material in this way, even if it is heated by the collision of an electron beam, thermal expansion is small, and mislanding can be reduced to a negligible level to prevent deterioration of color purity.

Conventionally, in this shadow mask, even if the shadow mask main body is formed of a low thermal expansion material, the frame is formed of an iron material such as a cold-rolled steel plate having a larger thermal expansion coefficient for cost reasons. I have. In such a shadow mask, the welding between the shadow mask body and the frame,
It is limited to eight points on the long axis, short axis, and diagonal axis, and only those along these points have been put to practical use.

However, if the shadow mask whose main body is made of a low thermal expansion material and whose frame is made of an iron material is applied to a recently developed, super-large, high-definition color picture tube having an aspect ratio of 16: 9, the environmental temperature changes. There is a problem that a mislanding is caused by this.

As shown in FIG. 6, at normal temperature, the electron beam 6 (6B, 6G, 6R) passing through the electron beam passage hole 11 of the shadow mask 4 is irradiated with a predetermined phosphor layer 17 of the phosphor screen 3. (17B, 17G, 17R), even if a correct landing is obtained, for example, if the ambient temperature becomes higher than room temperature, the panel 1 thermally expands,
The phosphor layer 17 moves to the position indicated by 17a. However, in this case, even if the frame 15 thermally expands, the thermal expansion of the frame 15 is absorbed by the deformation of the skirt portion 12 of the shadow mask body 13 and the shadow mask 4 is made of the low thermal expansion material. Since the effective surface 10 is hardly affected by a temperature change, the position of the electron beam passage hole 11 does not change. Therefore, a mislanding indicated by Δl occurs.

The 32-inch horizontal color picture tube will be described in detail. The temperature when adjusting the color picture tube by attaching a deflecting device is 15 ° C., the temperature during operation is 35 ° C., and the temperature difference ΔT is 20 ° C. Then, since the major axis of the screen is about 332 mm from the center of the screen to the major axis end, and the thermal expansion coefficient αp of the glass panel is 1.0 × 10 ⁻⁵ / ° C., Δl = 332 (1.0 × 10 ⁻⁵ × 20) = 0.0664 mm. On the other hand, the thermal expansion coefficient αm of the shadow mask body made of amber is 1.0 × 10 ⁻⁶ / ° C. or less, which is 1/10 or less of the panel. Therefore, a landing deviation of 0.06 mm occurs. This landing deviation is a considerably large deviation amount for the color picture tube, and affects color purity.

Conversely, if the temperature during operation drops,
A landing displacement occurs in a direction opposite to the landing displacement.

When the shadow mask main body is made of an iron material, the thermal expansion coefficient is about 1.2 × 10 ⁻⁵ / ° C., which is not much different from the thermal expansion coefficient αp of the panel. It is small enough to hardly matter.

However, as described above, the shadow mask body is made of a low thermal expansion material and cannot be ignored in a large color picture tube.

A shadow mask whose shadow mask body is made of a low thermal expansion material has much better characteristics for local doming than a shadow mask whose shadow mask body is made of an iron material. There is a need for a means for solving the deviation.

As means for solving the above-mentioned problem of the environmental temperature, Japanese Patent Application Laid-Open No. 1-200539 by the present applicant discloses a welding point at a position between the diagonal axis and the long axis of the shadow mask which is close to the long axis. In order to weaken the rigidity of the skirt portion of the shadow mask body in the short axis direction at this welding point, a cutout or the like is provided in the skirt portion.

However, if a notch or the like is provided in the skirt portion as in this shadow mask, local deformation occurs in the effective surface during molding of the shadow mask body, or high temperature heating in the manufacturing process of the color picture tube causes There is a problem that local deformation easily occurs on the effective surface.

[0016]

As described above, in order to prevent the color purity from deteriorating due to the doming of the shadow mask, the shadow mask body is made of a low thermal expansion material, and the frame is made of an iron material having a larger thermal expansion coefficient. There is a shadow mask formed. In this shadow mask, only those in which the welding between the shadow mask body and the frame is limited to eight points on the major axis, the minor axis, and the diagonal axis are in practical use. However, when such a shadow mask is applied to a recently developed horizontally large, high-definition color picture tube having an aspect ratio of 16: 9, there is a problem that mislanding occurs with a change in environmental temperature.

As means for solving the above-mentioned problem of the environmental temperature, a shadow point is provided at a position close to the major axis between the diagonal axis and the major axis of the shadow mask, and the skirt portion of the shadow mask body at this weld point is provided. In order to weaken the rigidity of the skirt in the short axis direction, a skirt provided with a notch or the like has been proposed. However, if notches are provided in the skirt part like this,
There is a problem that local deformation is likely to occur on the effective surface due to high-temperature heating during the molding of the shadow mask main body or the manufacturing process of the color picture tube.

The present invention has been made to solve the above problems, and has a shadow mask having a welding point between a shadow mask main body and a frame at a position between a diagonal axis and a long axis and near the long axis. In color picture tubes equipped with a color picture tube, there is no local deformation of the effective surface due to high temperature heating during the formation of the shadow mask body or the manufacturing process of the color picture tube, and color landing that does not cause mislanding even if the environmental temperature changes It is intended to be a tube.

[0019]

SUMMARY OF THE INVENTION A substantially rectangular shadow mask body made of a low thermal expansion material and provided with a skirt at the periphery of an effective surface having a large number of electron beam passage holes formed therein, In a color picture tube having a substantially rectangular shadow mask composed of a substantially rectangular frame made of an iron material having a side wall portion welded to a skirt portion at a plurality of welding points, a skirt portion of a shadow mask body and a frame of the frame are provided. The side wall is welded at a position close to the long axis between the diagonal axis and the long axis of the shadow mask, and a cut that reduces the rigidity of the frame in the short axis direction by approaching the welding point near the long axis. Chips formed.

Further, the notch is formed between the diagonal axis and the long axis with a welding point at a position close to the long axis.

[0021]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a color picture tube which is one embodiment of the present invention. This color picture tube has an envelope composed of a substantially rectangular glass panel 1 having a skirt portion 21 provided around an effective portion 20 and a funnel 2 having a funnel shape. A phosphor screen 3 made of a three-color phosphor layer is provided on the inner surface of the panel 1. Also, this phosphor screen 3
And a substantially rectangular shadow mask 2 inside thereof.
2 is a stud pin 23 provided on a skirt portion 21 at a corner portion of the panel 1 and a shadow mask 22 described later.
The frame is supported by an elastic support 24 which is attached to the side wall of the corner portion of the frame and is engaged with the stud pin 23. On the other hand, an electron gun 7 for emitting three electron beams 6B, 6G, 6R (only 6G is shown) is arranged in the neck 5 of the funnel 2. Then, the three electron beams 6B, 6G, 6R emitted from the electron gun 7 are converted into a funnel 2
The screen is deflected by a deflecting device 8 mounted outside the screen, and is selected by a shadow mask 22 so that the phosphor screen 3 is horizontally and
It is formed in a structure for displaying a color image by performing vertical scanning.

As shown in FIG. 2, the shadow mask 22 is provided with a large number of electron beam passage holes 27 on an effective surface 26 facing the phosphor screen.
A substantially rectangular shadow mask body 29 provided with a skirt 28 around the periphery of the shadow mask body 29;
And a substantially rectangular frame 31 having a side wall portion 30 welded to the skirt portion 28. The shadow mask main body 29 is formed of a low thermal expansion material such as amber having a thermal expansion coefficient equal to or less than 鉄 of iron, and the frame 31 is formed of an iron material such as a cold-rolled steel plate.

In particular, in this embodiment, as shown in FIG. 2, the major axis (X axis) and the diagonal axis (D
Short side wall 30 of the frame 31 close to the long axis between
A pair of notches 33 are formed near the phosphor screen side edge parallel to the tube axis to be close to each other, and the skirt 28 of the shadow mask body 29 and the side wall 3 of the frame 31 are formed.
0 means that the shadow mask 22 is welded between the two notches 33 between the diagonal axis and the long axis, in addition to the eight points on the long axis, the short axis (Y axis), and the diagonal axis, It is welded at a total of 12 welding points.

As described above, the shadow mask main body 29 made of a low thermal expansion material and the frame 31 made of an iron material are connected to the long axis, the short axis, and the eight points on the diagonal axis and between the long axis and the diagonal axis. Notch 3 in short side wall 30 of frame 31 near the long axis
By forming 3 and welding, it prevents mislanding when the environmental temperature changes, and causes local deformation on the effective surface even if it is heated at a high temperature during the formation of the shadow mask main body or the manufacturing process of the color picture tube. A color picture tube that does not generate a color picture can be obtained.

That is, the panel and the shadow mask of the color picture tube expand and contract as the environmental temperature changes. For example, when the environmental temperature increases, as shown in FIG.
No. 2 undergoes thermal expansion displacement as indicated by the solid line. in this case,
In the shadow mask 22 in which the shadow mask main body 29 is made of a low thermal expansion material and the frame 31 is made of an iron material, since the frame 31 thermally expands greatly with respect to the shadow mask main body 29,
The effective surface 26 of the shadow mask main body 29 changes in a direction away from the phosphor screen 3. Accordingly, at normal temperature, the electron beam 6 (6B, 6G, 6R) that has properly landed on the predetermined phosphor layer 35 (35B, 35G, 35R) through an arbitrary electron beam passage hole 27 is turned on the effective surface 26. The phosphor layer 35a, which has moved along with the change in the direction of moving away from the phosphor screen 3 through the electron beam passage hole 27a and has moved with the thermal expansion of the panel 1, is landed, and the desired beam landing is maintained.

Initially, the shadow mask 22 welded at a position near the major axis between the diagonal axis and the major axis as described above,
It was not clear why the effective surface 26 of the shadow mask main body 29 was displaced away from the phosphor screen 3. From FIG. 3, it was considered that the skirt portion 28 was pulled by the thermal expansion of the frame 31 and the deformation stress applied to the effective surface 26. If this was the cause, the shadow mask body would have a low thermal expansion. In the case of a shadow mask made of iron material and frame, there is no welding point near the long axis between the diagonal axis and the long axis, and the same applies to a conventional shadow mask that has welding points on the long axis. Displacement should occur. However, it does not actually occur.

That is, in the shadow mask composed of the shadow mask body made of the low thermal expansion material and the frame made of the iron material, the skirt portion and the side wall portion are welded at a position close to the major axis between the diagonal axis and the major axis. Then, the characteristics of the shadow mask are greatly changed.

As a result of analyzing the change in the characteristics of the shadow mask by the finite element method, the skirt portion 28 of the shadow mask main body 29 and the side wall portion 30 of the frame 31 were analyzed as described above.
Is welded at a position near the major axis between the diagonal axis and the major axis, elongation (deformation) having major-axis and minor-axis components occurs due to the difference in thermal expansion between the shadow mask body 29 and the frame 31. It turned out to be the case.

The longitudinal component Δx of the elongation coincides with the thickness direction of the skirt portion 28 of the shadow mask body 29,
Since the skirt portion 28 can be easily deformed in the thickness direction, the long axis direction component Δx is absorbed by the deformation of the skirt portion 28 and does not deform the effective surface 26. However, since the short-axis direction component Δy is a direction along the plate surface of the skirt portion 28, it is not absorbed by the skirt portion 28 and deforms the effective surface 26.

In the above-mentioned Japanese Patent Application Laid-Open No. Hei 1-200539, in order to prevent the short-axis direction component Δy from reaching the effective surface of the shadow mask body, a notch is provided in the skirt portion to weaken the short-axis direction rigidity. However, when the notch is provided in the skirt portion in this way, there is a problem that the effective surface is locally deformed due to high-temperature heating during the formation of the shadow mask main body and the manufacturing process of the color picture tube.

However, as in this embodiment, the notch 33 is formed in the short side wall 30 of the frame 31 by approaching the welding point near the long axis between the diagonal axis and the long axis. When welding is performed, the rigidity in the short axis direction of the short side wall portion 30 near the welding point can be reduced, and the deformation of the frame 31 near the welding point absorbs the short axis component Δy of the elongation, The deformation of the effective surface 26 of the shadow mask main body 29 can be prevented. In particular, by providing a pair of notches 33 sandwiching the welding point, the short side wall portion 30 can be effectively formed.
Of the shadow mask main body 29 can be prevented from being deformed.

Although the above embodiment has been described with reference to a case where the environmental temperature is high, the shadow mask configured as described above can achieve the same effect even when the environmental temperature is low.

In the above embodiment, the case where the shadow mask has a welding point on the long axis of the shadow mask body and the frame has been described. However, the present invention is applicable even if the welding point is omitted on the long axis. Thus, a shadow mask having a similar effect can be obtained.

[0035]

The skirt portion of the shadow mask body and the side wall portion of the frame are welded at a position close to the long axis between the diagonal axis and the long axis of the shadow mask. Notches that reduce the rigidity in the short axis direction prevent mislanding when the environmental temperature changes, and even when heated at high temperatures during the formation of the shadow mask body and the manufacturing process of the color picture tube, A color picture tube which does not cause any significant deformation can be constructed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a color picture tube according to an embodiment of the present invention.

2A is a plan view showing a configuration of a shadow mask of the color picture tube, FIG. 2B is a front view thereof, and FIG.
(C) is a side view.

FIG. 3 is a diagram for explaining an operation of the shadow mask.

FIG. 4 is a diagram showing a configuration of a conventional color picture tube.

5A is a plan view showing the configuration of a shadow mask of the conventional color picture tube, FIG. 5B is a front view thereof, and FIG. 5C is a side view.

FIG. 6 is a diagram for explaining the operation of the conventional shadow mask.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 22 ... Shadow mask 26 ... Effective surface 27 ... Electron beam passage hole 28 ... Skirt part 29 ... Shadow mask body 30 ... Side wall part 31 ... Frame 33 ... Notch

Claims (2)

[Claims] 1. A substantially rectangular shadow mask body made of a low thermal expansion material having a skirt at the periphery of an effective surface formed with a large number of electron beam passage holes, and a plurality of skirts on the shadow mask body. In a color picture tube provided with a substantially rectangular shadow mask composed of a substantially rectangular frame made of an iron material having a side wall portion welded at a welding point, a skirt portion of the shadow mask body, a side wall portion of the frame, Is welded at a position near the long axis between the diagonal axis and the long axis of the shadow mask, and a notch is formed to approach the welding point at a position near the long axis and weaken the rigidity of the frame in the short axis direction. A color picture tube characterized by being made. 2. The color picture tube according to claim 1, wherein the notch is formed so as to sandwich a welding point between the diagonal axis and the major axis at a position close to the major axis.