JP2000036256A - Color picture tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the permanent deformation of an elastic carrier due to the mounting and dismounting of a shadow mask or shock and thereby provide good beam landing by setting the ratio of the plate thickness of a fixing part fixed to the corner part of a mask frame to that of a lock part locked to a stud pin in a specific range. SOLUTION: Each elastic carrier 34 is composed of a fixing part 36 mounted to a mask frame, a lock part 38 provided with a lock hole 37 fitted to a stud pin and a tilting part 39 formed by bending the lock part 38, and one end of the tilting part 39 is fixed to one end of the fixing part 36 by means of welding. In addition, torsion preventing parts 40, 41 are protrusively formed perpendicularly to the plate surface on both sides in the widthwise direction of the fixing part 36 and the lock part 38. Then, if the plate thickness T2 of the fixing part 36 is set to 1.4-1.6 times as much as the plate thickness T1 of the lock part 38 and the tilting part 39, the degradation of workability for mounting and dismounting a shadow mask in forming a phosphor screen can be prevented, and permanent deformation due to the mounting and dismounting of the shadow mask which are repeated in forming the phosphor screen and at the time shock is applied to a picture tube can be restrained.

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 a beam landing is prevented from shifting due to permanent deformation of an elastic support for supporting a shadow mask.

[0002]

2. Description of the Related Art Generally, in a color picture tube, a substantially rectangular shadow mask is arranged to face a phosphor screen formed of a three-color phosphor layer provided on the inner surface of a substantially rectangular panel. The three electron beams emitted from the electron gun are selected to be incident on the three-color phosphor layer. The shadow mask comprises a substantially rectangular mask body provided with a large number of electron beam passage holes on a surface facing the phosphor screen, and a substantially rectangular mask frame attached to a periphery of the mask body. The elastic support attached to the mask frame is detachably supported by engaging a stud pin provided on the panel.

As a method for supporting the shadow mask, as shown in FIG. 4, an elastic support 1 is formed in a structure having an inclined portion 2 inclined with respect to a tube axis (Z axis). Some are attached to the part. When the shadow mask 4 is supported by such an elastic support 1, when the shadow mask 4 thermally expands as shown by a dashed line,
By pushing up in the direction of the phosphor screen 6 provided on the inner surface of the panel 5, it is possible to correct the deviation of the beam landing from the three-color phosphor layer due to the thermal expansion of the shadow mask 4.

As a specific design example of such an elastic support, as shown in FIG. 5, a fixing portion 8 fixed to the mask frame 3, a locking portion 10 locking to the stud pin 9, and these fixing portions Inclined portion 11 inclined to 8 and locking portion 10
Is bent, and the fixed portion 8 and the locking portion 10 extend in opposite directions with respect to the inclined portion 11 of the elastic support 1.
There is.

[0005] However, the elastic support 1 has one point due to the force applied to the locking portion 10 when the shadow mask 4 is repeatedly attached and detached when the phosphor screen is formed by a photographic printing method using the shadow mask 4 as an optical mask. As shown by the dashed line, there is a problem that permanent deformation due to plastic deformation occurs and the shape cannot be returned to the original shape.

As a solution to the problem of the elastic support 1, as shown in FIG. 6, the fixed portion 8 and the locking portion 10 are bent in the same direction with respect to the inclined portion 11 by bending. Some have a wedge shape.

When the wedge shape is formed by bending as described above, even when a force is applied to the locking portion 10 when the shadow mask 4 is attached or detached, the fixing portion 8 and the mask frame 3 are connected with each other as shown by a dashed line. Starting from the welding point, the entire part bends, and permanent deformation due to plastic deformation that does not return to the original shape can be reduced. However, when an impact is applied to the color picture tube, the bent elastic support 1 is engaged with the locking portion 1 via a stud pin as shown in FIG.
0, a force F1 acting in the direction indicated by an arrow 13a acts, and in response thereto, a force F2 acting in the opposite direction indicated by an arrow 13b on the fixing portion 8.
Works. Such couples F1 and F2 are applied to both ends 15a and 15a of the bent portion 14 between the fixed portion 8 and the inclined portion 11.
b, and as shown by the dashed line in (b),
Permanent deformation that tilts the locking portion 10 occurs. This is because, as shown in (c), the curved portion of the bent portion 14 indicated by an arrow is easily bent, the radius of the arc at the end 15a is relatively small, and the radius of the arc at the end 15b is relatively small. Is relatively large.

Further, in order to reduce the deformation of the elastic support 1, as shown in FIG. 8, a locking portion 10 and an inclined portion 11 are formed by bending, and one end of the inclined portion 11 is formed. There is an elastic support 1 in which one end of the fixing portion 8 is welded.

By forming in this manner, the fixing portion 8
The strength of the boundary between the and the inclined portion 11 can be improved. However, even with the elastic support 1 thus formed, when the forces F1 and F2 shown in FIG. 7A are applied, the amount of deformation is small as shown by the dashed line in FIG. A similar permanent deformation of tilting occurs.

In order to make the permanent deformation substantially zero, the plate thickness may be increased. However, when the plate thickness is increased, the spring pressure of the elastic support 1 increases, and the workability of attaching and detaching the shadow mask is reduced. Not only deteriorates, but also deforms the thin mask body.

An elastic support 1 which solves such a problem.
As shown in FIG. 10, as shown in FIG.
On both sides in the width direction of 0, there is an elastic support body 1 having anti-twisting portions 17, 18 protruding substantially at right angles.

By providing the twist preventing portions 17 and 18 in this manner, permanent deformation due to attachment and detachment of the shadow mask and permanent deformation due to the impact force applied to the locking portion 10 via the stud pins can be achieved without increasing the plate thickness. Thus, the deviation of the beam landing from the three-color phosphor layer can be reduced.

[0013]

As described above, when the elastic support for supporting the shadow mask is formed to have a structure having an inclined portion inclined with respect to the tube axis, the phosphor screen is thermally expanded when the shadow mask is thermally expanded. In this case, the deviation of the beam landing from the three-color phosphor layer due to the thermal expansion of the shadow mask can be corrected.

Specific examples of the design of such an elastic support include: (a) a fixing portion fixed to a mask frame, a locking portion for locking to a stud pin, and a slope inclined to these fixing portion and locking portion. The elastic support member has a bent portion, and the fixed portion and the locking portion extend in opposite directions to the inclined portion. (B) The fixed portion and the locking portion are aligned in the same direction with respect to the inclined portion. (C) an elastic support formed by bending a locking portion and an inclined portion and welding one end of the inclined portion and one end of a fixed portion; Various types of structures are known, such as an elastic support in which a torsion preventive portion is formed on both sides in the width direction of the fixed portion and the locking portion of the elastic support in (c), and is formed substantially at right angles. With the configuration as shown in the figure, the attachment / detachment of the shadow mask Applied to reduce the permanent deformation due to an impact force, it is possible to reduce the deviation of beam landing relative to the three-color phosphor layers.

However, in recent high definition color picture tubes, stricter beam landing is required.
The elastic support is no longer able to cope.

The present invention has been made in view of the above problems, and constitutes a color picture tube capable of obtaining a good beam landing by reducing permanent deformation of an elastic support due to attachment and detachment of a shadow mask and impact. The purpose is to:

[0017]

A substantially rectangular mask body facing a phosphor screen provided on the inner surface of the substantially rectangular panel and a substantially rectangular mask attached to the periphery of the mask body are provided inside the substantially rectangular panel. A substantially rectangular shadow mask composed of a mask frame having a shape is disposed, and the shadow mask is fixed to a corner portion of the panel, a stud pin fixed to the corner portion of the mask frame, and locked to the stud pin. In a color picture tube supported by an engaging portion to be fixed and an elastic support having an inclined portion inclined to the fixing portion and the engaging portion, the thickness of the fixing portion of the elastic support is determined by the thickness of the engaging portion. 1.4 to 1.6 times.

Further, the elastic support has a structure in which a locking portion and an inclined portion are formed by bending and a fixed portion is welded to the inclined portion.

[0019]

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 panel 21 provided with a skirt portion 20 on the periphery and a funnel 22 in a funnel shape. On the inner surface of the panel 21, a phosphor screen 23 composed of a three-color phosphor layer that emits blue, green, and red light is provided. A substantially rectangular shadow mask 24 faces the phosphor screen 23.
Is arranged. On the other hand, the neck 25 of the funnel 22
An electron gun 27 for emitting three electron beams 26B, 26G, 26R is provided therein. Then, the three electron beams 26B, 26G, 26R emitted from the electron gun 27 are deflected by a deflecting device 28 mounted outside the funnel 22, and the phosphor screen 23 is horizontally and vertically scanned through the shadow mask 24. As a result, a structure for displaying a color image is formed.

As shown in FIG. 2, the shadow mask 24 has a substantially rectangular mask body 31 provided with a large number of electron beam passage holes 30 on a surface facing the phosphor screen.
And a substantially rectangular mask frame 32 attached to the periphery of the mask main body 31. As shown in FIG. 1, a stud pin 33 provided on the skirt portion 20 at the corner of the panel 21, An elastic support 34 attached to the corner of the mask frame 32 and engaged with the stud pins 33 supports the inside of the panel 21.

As shown in FIG. 3, the elastic support 34 has a fixing portion 36 attached to the mask frame and a locking portion 3 provided with a locking hole 37 for fitting to the stud pin.
8 and a wedge shape formed by the fixed portion 36 and the inclined portion 39 inclined to the locking portion 38. The locking part 3
8 and the inclined portion 39 are formed integrally by bending, and have a structure in which one end of the inclined portion 39 and one end of the fixed portion 36 are fixed by welding. On both sides in the width direction of the fixing portion 36 and the locking portion 38, twist preventing portions 40, 41 are formed to project substantially perpendicularly to the plate surface.

Particularly, in this embodiment, the locking portion 38
And the plate thickness T2 of the fixed portion 36 is T2 = 1.4 to 1.6T1 with respect to the plate thickness T1 of the inclined portion 39.

As described above, when the plate thickness T2 of the fixing portion 36 fixed to the mask frame 32 is set to be 1.4 to 1.6 times the plate thickness T1 of the locking portion 38 and the inclined portion 39, the phosphor screen is used. The locking portion is tilted when the shadow mask 24 is repeatedly attached and detached during the formation of the phosphor screen 23 and the impact is applied to the color picture tube without deteriorating the workability of attaching and detaching the shadow mask 24 when forming the phosphor screen 23. Due to the permanent deformation (see FIG. 9), the phenomenon that the locking portion bites into the stud pin due to the inclination thereof can be suppressed, and a color picture tube with good beam landing can be obtained.

As a specific example, for a 20-inch 110-degree deflecting color picture tube, the thickness T1 of the locking portion and the inclined portion of the wedge-shaped elastic support supporting the shadow mask is 0.5 mm, and the plate of the fixed portion is The thickness T2 is 0.8 mm (T2 = 1.6
T1), and the change in beam landing due to the impact applied when the color picture tube is dropped in the horizontal direction is expressed as
As a result of comparison with a conventional color picture tube in which a shadow mask is supported by an elastic support of the same shape formed with the same thickness of the locking portion, the inclined portion, and the fixed portion having a thickness of 0.5 mm, While the maximum beam landing deviation of the tube is 50 μm, in the color picture tube of this embodiment, the maximum beam landing deviation is 25 μm.
m was reduced by half.

In the above-described embodiment, the plate thickness T2 of the fixing portion 36 is 1.4 to 1.6 times the plate thickness T1 of the locking portion 38 and the inclined portion 39, but T2 is T1. 1.6
If it exceeds twice, not only the workability of attaching and detaching the shadow mask 24 is deteriorated due to the increase of the spring pressure of the elastic support, but also the elastic support is permanently deformed, and the change of the beam landing due to the external impact increases. On the other hand, when the ratio is less than 1.4 times, the spring pressure of the elastic support becomes too weak and does not affect the workability of attaching and detaching the shadow mask 24 and the permanent deformation of the elastic support, but the beam landing due to the external impact is not affected. Change increases.

[0027]

When the thickness of the fixed portion of the elastic support supporting the shadow mask is set to 1.4 to 1.6 times the thickness of the locking portion, the work of attaching and detaching the shadow mask when forming the phosphor screen. Without deteriorating the performance, the shadow mask is repeatedly attached and detached at the time of forming the phosphor screen, permanent deformation when an impact is applied to the color picture tube, and further, the locking portion cuts into the stud pin due to its inclination A color picture tube in which the phenomenon is suppressed and good beam landing can be obtained can be obtained.

[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.

FIG. 2 is a diagram showing a configuration of a shadow mask of the color picture tube.

FIG. 3 is a diagram showing a configuration of an elastic support for supporting the shadow mask.

FIG. 4 is a diagram for explaining beam landing deviation correction when a shadow mask is thermally expanded by an elastic support having an inclined portion.

FIG. 5 is a diagram showing a specific design example of an elastic support having an inclined portion.

FIG. 6 is a view showing a specific example of a different design of an elastic support having an inclined portion.

7 (a) to 7 (c) are views for explaining permanent deformation of the elastic support shown in FIG. 6;

FIG. 8 is a view showing another specific example of a different design of the elastic support having the inclined portion.

FIG. 9 is a view for explaining permanent deformation of the elastic support shown in FIG. 8;

FIG. 10 is a diagram showing a further different design example of an elastic support having an inclined portion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 21 ... Panel 23 ... Phosphor screen 24 ... Shadow mask 31 ... Mask main body 32 ... Mask frame 33 ... Stud pin 34 ... Elastic support 36 ... Fixed part 38 ... Locking part 39 ... Inclined part

Claims (2)

[Claims] 1. A substantially rectangular mask body facing a phosphor screen provided on an inner surface of the substantially rectangular panel inside the panel, and a substantially rectangular mask frame attached to a peripheral portion of the mask body. A shadow mask having a substantially rectangular shape comprising: a stud pin provided at a corner portion of the panel; a fixing portion fixed to a corner portion of the mask frame; In a color picture tube supported by a stopper and an elastic support having an inclined portion inclined to the fixing portion and the locking portion, the elastic support has a plate thickness of the fixing portion. A color picture tube characterized in that the thickness is 1.4 to 1.6 times the thickness. 2. The elastic support according to claim 1, wherein the elastic support has a locking portion and an inclined portion formed by bending and a fixed portion is welded to the inclined portion. Color picture tube.