JP2003288850A - Cathode-ray tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal magnetic shield in which a first shield piece and a second shield piece can be stably jointed with a simple structure and a cathode-ray tube having the same. <P>SOLUTION: The bottom wall 171 of the first shield piece 18 has a slope of separating away from the frame 13 from the center toward the edge part between the protrusion 151 and the frame hole 141, and on the other hand, the bottom wall 172 of the second shield piece 19 has a slope of separating away from the frame 13 from the edge part toward the center between the protrusion 152 and the frame hole 142, and thereby, they exert mutually reversed direction force at the portion where the bottom wall 171 of the first shield piece 18 and the bottom wall 172 of the second shield piece 19 are overlapped each other. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube, and more particularly to a structure of an internal magnetic shield provided inside the cathode ray tube for suppressing mislanding of an electron beam due to an external magnetic field such as earth magnetism.

[0002]

2. Description of the Related Art FIG. 11 is a side sectional view of a color cathode ray tube.

The front panel 1 and the funnel 2 are integrated to form an envelope 3. On the inner surface of the front panel 1,
A phosphor screen 4 is formed. The color selection electrode (for example, shadow mask) 5 fixed to the frame 13
It faces the phosphor screen 4. The frame 13 is
By holding a leaf spring-like elastic support body (not shown) installed on the outer peripheral surface thereof on a panel pin (not shown) provided on the inner surface of the front panel 1, it is held by the front panel 1. There is. An electron gun 6 is built in the neck portion of the funnel 2. A deflection yoke 8 is provided on the outer peripheral surface of the funnel 2.
Are provided, the electron beam 7 from the electron gun 6 is deflected in the horizontal direction and the vertical direction, and is scanned on the phosphor screen 4.

When an external magnetic field such as terrestrial magnetism acts on the cathode ray tube, the orbit of the electron beam 7 changes, and so-called mislanding occurs in which the electron beam 7 does not reach a desired position on the phosphor screen 4. As a result, in the color cathode ray tube, an unfavorable phenomenon such as color misregistration occurs and the quality of the displayed image is deteriorated. The direction of the external magnetic field differs depending on the installation direction of the cathode ray tube, and the magnitude thereof depends on the installation position of the cathode ray tube. Therefore, in order to always perform stable image display regardless of the installation direction and installation position of the cathode ray tube, the electron beam 7 is shielded from the external magnetic field, or the external magnetic field is converted into a magnetic field in a direction in which at least mislanding does not occur. There is a need to. For this purpose, the internal magnetic shield 20 is installed inside the cathode ray tube.

FIG. 12 is a perspective view of a conventional internal magnetic shield, in which (a) shows a disassembled state and (b) shows an assembled state. Internal magnetic shield 20
Is pressed or bent and has a bottom of 90 °
First shield piece 18 consisting of two trapezoidal wall surfaces forming
And a second shield piece 19 having substantially the same shape as the first shield piece 18 are combined. They are,
It is joined by resistance welding or the like so as to form a part of the substantially square pyramid surface. The inner magnetic shield 20 is blackened after being assembled.

[0006]

In the above construction, in addition to the need for a welding process, there is a problem that the blackening treatment furnace has a low treatment efficiency because it is blackened after assembly.

As shown in FIG. 13, a method has been proposed in which a projecting piece 101 for bending is provided on the upper ends of two opposing press-molded shield pieces 18, 19 and the projecting piece 101 is bent and connected. (A) shows the disassembled state, and (b) shows the assembled state. However, in this configuration, the coupling force is relatively weak, and there is a problem that foreign matter is generated in the cathode ray tube due to abrasion when the two press-molded parts are rubbed by vibration.

Further, Japanese Patent Application Laid-Open No. 11-67117 proposes shapes of a connecting piece and a connecting hole for connecting two press-molded shield pieces.
However, this configuration requires a step of bending, and there is a problem in that spring back occurs due to heat treatment or the like performed in the subsequent manufacturing process of the cathode ray tube, and the bending coupling force is reduced.

The present invention has been made to solve the above various problems, and an internal magnetic shield capable of stably coupling the first shield piece and the second shield piece with a simple structure. , And a cathode ray tube provided with the same.

[0010]

A cathode ray tube according to the present invention is formed on an inner surface of the front panel, an envelope including a front panel and a funnel, an electron gun provided in a neck portion of the funnel. A cathode ray tube having a phosphor screen, a color selection electrode facing the phosphor screen, a frame to which the color selection electrode is fixed, and an internal magnetic shield fixed to the frame, wherein the internal magnetic shield Is composed of a first shield piece and a second shield piece having a bottom wall fixed to the frame, and the bottom wall of the first shield piece exerts a force to keep it away from the frame in the vicinity of its end. On the other hand, the bottom wall of the second shield piece receives a force such that the second shield piece is pressed against the frame in the vicinity of the end portion thereof. Characterized in that it each other exerts a force opposite to each other the ends overlap of the second shield piece on the end portion (claim 1).

According to the present invention, at the ends where the bottom walls overlap each other, the respective bottom walls exert mutually opposite forces. By this action, the first shield piece and the second shield piece are stably fixed to the frame without slipping each other.

Further, the cathode ray tube of the present invention comprises an envelope consisting of a front panel and a funnel, an electron gun provided in the neck portion of the funnel, and a phosphor screen formed on the inner surface of the front panel. A cathode ray tube having a color selection electrode facing the phosphor screen, a frame to which the color selection electrode is fixed, and an internal magnetic shield fixed to the frame, wherein the internal magnetic shield is the frame. Of the first shield piece and the second shield piece having a bottom wall fixed to
On the surface of the first shield piece to which the bottom wall is fixed, a protrusion is provided near the end thereof, and a bottom fixing portion for fixing the bottom wall is provided closer to the center than the protrusion. On the surface of the second shield piece to which the bottom wall is fixed, a bottom fixing portion is provided near the end thereof, and a projecting portion is provided closer to the center than the bottom fixing portion. The end portion of the second shield piece overlaps the end portion of the first shield piece (claim 2).

According to the present invention, at the ends where the bottom walls overlap each other, the bottom walls exert mutually opposite forces. By this action, the first shield piece and the second shield piece are stably fixed to the frame without slipping each other.

Further, in the cathode ray tube according to the present invention, the first shield piece and the second shield piece are respectively formed of a trapezoidal long side wall and a short side wall, and continue from the oblique side of the long side wall. A first side wall and a second side wall continuing from a hypotenuse of the short side wall, wherein the first side wall of the first shield piece and the second side wall of the second shield piece overlap each other, and
The second side wall of the shield piece and the first side wall of the second shield piece overlap with each other, a coupling piece is provided on the side wall of the first shield piece, and the second side wall of the second shield piece is coupled with the coupling piece. A coupling hole into which the piece is inserted is provided (claim 3).

According to the present invention, at the end portions where the bottom walls overlap each other, the respective bottom walls exert mutually opposite forces. By this action, the engagement between the coupling piece and the coupling hole is maintained, and the first shield piece and the second shield piece are stably fixed without slipping each other.

Further, the coupling piece is in the form of a tongue protruding from the side wall toward the electron gun (claim 4).

Further, in the cathode ray tube according to the present invention, the first shield piece and the second shield piece each have a trapezoidal long side wall and a short side wall, respectively, and extend from the oblique side of the long side wall. A first side wall and a second side wall continuing from a hypotenuse of the short side wall, wherein the first side wall of the first shield piece and the second side wall of the second shield piece overlap each other, and
The second side wall of the shield piece and the first side wall of the second shield piece overlap each other, and a coupling piece is provided on the side wall of the second shield piece, and the coupling piece is connected to the side wall of the first shield piece. A coupling hole into which the piece is inserted is provided (Claim 5).

According to the present invention, at the end portions where the bottom walls overlap each other, the bottom walls exert mutually opposite forces. By this action, the engagement between the coupling piece and the coupling hole is maintained, and the first shield piece and the second shield piece are stably fixed to the frame without slipping each other.

Further, the coupling piece is in the form of a tongue protruding from the side wall toward the front panel (claim 6).

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The structures of the internal magnetic shield and frame, which are the features of the present invention, will be described in detail.

FIG. 1 is a perspective view showing a state in which the internal magnetic shield and the frame according to the present invention are disassembled.

The inner magnetic shield 20 is fixed to the surface 131 of the frame 13 opposite to the surface facing the phosphor screen. The inner magnetic shield 20 includes a first shield piece 18 including a trapezoidal long side wall 181 and a short side wall 182.
And a trapezoidal long side wall 191 and a short side wall 192,
The second shield piece 1 having substantially the same shape as the first shield piece 18
9 and 9. That is, the inner magnetic shield 20 is in a form of being divided into two along a diagonal line. In the first shield piece 18, a trapezoidal long side wall 181 and a short side wall 182 form a base of 90 ° and are bent and connected at the oblique side. The same applies to the second shield piece 19.

FIG. 2 is a perspective view showing a state in which the first shield piece 18 and the second shield piece 19 are disassembled.

The first shield piece 18 is bent inward from the hypotenuse of the long side wall 181 and continues from the long side wall 181.
It has a side wall 21a and a second side wall 21b that is bent inward from the oblique side of the short side wall 182 and continues from the short side wall 182. The long side wall 181 and the short side wall 182 form a bottom side wall 171 fixed to the frame 13, which is bent outward at the bottom side and continues from the bottom side. Second shield piece 19
Similarly, the long side wall 191, the short side wall 192, the first side wall 22
a, the second side wall 22b, and the bottom wall 172, respectively.

A first side wall 21a of the first shield piece 18;
The second side wall 22b of the second shield piece 19 is formed so as to overlap with each other when the inner magnetic shield is assembled. In addition, the second side wall 21 of the first shield piece 18
b and the first side wall 22a of the second shield piece 19 are formed so as to overlap each other when the inner magnetic shield is assembled.

The first side wall 21a and the second side wall 21b of the first shield piece 18 are formed by cutting a part of the wall and raising the tongue-like connecting piece 23.
a and 23b are provided respectively. A coupling hole 24 into which the coupling pieces 23a and 23b are inserted and caught in the first side wall 22a and the second side wall 22b of the second shield piece 19.
a and 24b are provided respectively.

Bottom holes 161 and 163 are formed in the bottom wall 171 of the first shield piece 18, and the bottom wall 1 of the second shield piece 19 is formed.
Bottom holes 162 and 163 (not shown) are provided at 72, respectively. Bottom wall 171 of the first shield piece 18
Has ends protruding from the bottom sides of the long side wall 181 and the short side wall 182. Bottom wall 172 of second shield piece 19
Also, the end portions project from the bottom sides of the long side wall 191 and the short side wall 192. The bottom walls 171 and 172 have their ends overlapping with each other when the inner magnetic shield is assembled.

FIG. 3 shows a perspective view of the frame 13.

On the side of the frame 13 to which the bottom wall 171 of the first shield piece 18 is fixed, a protrusion (a "protruding portion" in the claims) 151 is provided near the end of the side. A frame hole 141 for fixing the bottom wall 171 of the first shield piece 18 closer to the center of the side than the protrusion 151.
Is provided (the "bottom edge fixing portion" in the claims). On the other hand, on the side where the bottom wall 172 of the second shield piece 19 is fixed, the frame hole 142 of the second shield piece 19 is provided near the end of the side, and is closer to the center of the side than the frame hole 142. A protrusion 152 is provided. Protrusion 1
51 and 152 are, for example, columnar ones. Further, a frame hole 143 is provided at the end where the protrusions 151 and 152 are not provided.

Next, the first shield piece 18 is attached to the frame 13.
The structure and sequence of fixing the second shield piece 19 will be described.

First, the first shield piece 18 is attached to the frame 13.
To fix.

In FIG. 4, the first shield piece 18 is attached to the frame 1
3 is a perspective view showing a state of being fixed to FIG. FIG. 5 is a side sectional view showing the frame 13 and the end portions of the bottom wall 171 in an enlarged manner.

A frame hole 14 provided in the frame 13
1, 143 and the bottom hole 16 provided in the bottom wall 171
1 and 163 are aligned with each other, the clamping spring 12 is inserted into each hole, and the frame 13 and the first shield piece 1 are inserted.
Fix 8 and. Bottom wall 171 of the first shield piece 18
Is pressed against the frame 13 by the clamping spring 12 at the position of the bottom hole 161 while the protrusion 1
The tip portion is lifted by 51 in response to a force in the direction away from the frame 13 (upward in the figure). That is, the bottom wall 171 has an inclination between the projection 151 and the bottom hole 161 that moves away from the frame 13 from the center toward the end. This is the same for the long side and the short side.

Next, the second shield piece 19 is attached to the frame 13
Fixed to.

FIG. 6 is a perspective view showing a state in which the second shield piece 19 is fixed to the frame 13 from above the first shield piece 18. FIG. 7 shows the frame 13 and the bottom wall 172.
FIG. 3 is a side cross-sectional view showing an enlarged end portion of FIG. For convenience of description, a case where only the second shield piece 19 is fixed to the frame 13 is shown.

A frame hole 14 provided in the frame 13
2, 143 and the bottom hole 16 provided in the bottom wall 172
Align the positions of 2, 163 (not shown), insert the clamping spring 12 into each hole,
The shield piece 19 is fixed. The bottom wall 172 of the second shield piece 19 is lifted upward by the protrusion 152, while the clamping spring 12 causes the frame 1 to move upward.
The tip end portion is pushed down by receiving a force such that the tip end portion 3 is pressed. That is, the bottom wall 172 has an inclination between the projection 152 and the bottom hole 162, which is distant from the frame 13 from the end toward the center. This is the same for the long side and the short side.

Further, the first side wall 21 of the first shield piece 18
a (not shown) on the second side wall 2 of the second shield piece 19.
2b overlap, and the coupling piece 23a of the first side wall 21a and the coupling hole 24b of the second side wall 22b are engaged with each other. Similarly,
The first side wall 22a of the second shield piece 19 overlaps the second side wall 21b (not shown) of the first shield piece 18,
The coupling piece 23b of the side wall 21b and the coupling hole 2 of the first side wall 22a
It meshes with 4a. 8A and 8B are partially enlarged views showing how the side walls are engaged with each other. FIG. 8A shows a disassembled state and FIG. 8B shows an engaged state.

At the ends of the bottom walls 171, 172,
The frame 13, the bottom wall 171 of the first shield piece 18, and the bottom wall 172 of the second shield piece 19 overlap in this order. As described above, the bottom wall 171 tends to move away from the frame 13 as it approaches the end portion, while the bottom wall 172 tends to approach the frame 13 as it approaches the end portion. Therefore, at the end where the bottom wall 171 and the bottom wall 172 overlap, the bottom wall 171 and the bottom wall 172 exert mutually opposite forces. By this action, the coupling piece 23
The engagement between the a and 23b and the coupling holes 24b and 24a is maintained, and the first shield piece 18 and the second shield piece 19 are stably fixed without slipping each other. Also,
Due to the principle of leverage, the clamping spring 12 is always in tension, so that the clamping spring 12 does not rattle.

The bottom wall and the frame are fixed not by the combination of the coupling hole and the clamping spring, but by the combination.
It can also be done by welding or screwing.

An example of the position and size of the protrusion and the coupling hole will be shown. On the long side of the frame 13, the distance from the end of the frame 13 to the center of the protrusion 151 is 20 mm, the distance to the frame hole 141 is 40 mm, and the height of the protrusion 151 is 2 mm. On the other hand, on the short side of the frame 13, the distance from the end of the frame 13 to the protrusion 152 is 35
mm, the distance to the frame hole 142 is 15 mm,
The height of the protrusion 152 is 2 mm.

As shown in FIG. 9, in addition to the connecting piece 23a and the connecting hole 24b, another set of connecting piece 25a and the connecting hole 26b is formed.
Is provided, the first shield piece 18 and the second shield piece 19
The bond with can be made stronger. Figure 9
[Fig. 4] is a partially enlarged view showing a state of engagement on a side wall, (a) shows a disassembled state, and (b) shows an engaged state.

Contrary to the above embodiment, it is also possible to provide a coupling hole in the first shield piece and a coupling hole in the second shield piece. That is, the first side wall and the second side wall of the second shield piece
Each of the side walls is provided with a downwardly projecting tongue-shaped coupling piece formed by cutting a part of the wall and raising it. On the other hand, the first side wall and the second side wall of the first shield piece are each provided with a coupling hole into which the coupling piece is inserted and hooked. Other parts are the same as those in the above embodiment. Also with this configuration, similarly to the above-described embodiment, at the end portions where the bottom walls overlap each other, mutually opposing forces are exerted, and the engagement between the coupling piece and the coupling hole is maintained.

10A and 10B show other configurations of the coupling piece and the coupling hole, FIG. 10A showing a disassembled state, and FIG. 10B showing a meshed state.

The first side wall 21a and the second side wall 21b (not shown) of the first shield piece 18 are each provided with a connecting piece 31 formed by cutting a part of the wall and raising it to form an L-shape. ing. The first side wall 2 of the second shield piece 19
2a (not shown) and the second side wall 22b have coupling pieces 3
The coupling holes 32 into which 1 is inserted and hooked are respectively provided.

The coupling hole 32 is composed of a portion having a width into which the coupling piece 31 can be inserted and a portion having a width slightly larger than the thickness of the coupling piece 31 and engaging with the coupling piece 31. When the second shield piece 19 and the first shield piece 18 are combined, the connecting piece 32 is formed so that the connecting piece 31 moves smoothly.
The two width parts are connected by a slope.

[0046]

As described above, the present invention provides an internal magnetic shield which has a simple structure and can be stably coupled to suppress wear and foreign matter due to vibration, and a cathode ray tube including the same. To do.

[Brief description of drawings]

FIG. 1 is a perspective view showing a state in which an internal magnetic shield and a frame according to the present invention are disassembled.

FIG. 2 is a perspective view showing a state in which a first shield piece and a second shield piece are disassembled.

FIG. 3 is a perspective view of a frame

FIG. 4 is a perspective view showing a state in which the first shield piece is fixed to the frame.

FIG. 5 is a side sectional view showing an enlarged end portion of a frame and a bottom wall.

FIG. 6 is a perspective view showing a state in which the first and second shield pieces are fixed to a frame.

FIG. 7 is a side sectional view showing an enlarged end portion of a frame and a bottom wall.

FIG. 8 is a partially enlarged view showing a state of engagement on the side wall.

FIG. 9 is a partially enlarged view showing a state of engagement on the side wall.

FIG. 10 is a partially enlarged view showing a state of engagement on the side wall according to the second embodiment.

FIG. 11 is a side sectional view of a color cathode ray tube.

FIG. 12 is a perspective view of a conventional internal magnetic shield.

FIG. 13 is a perspective view of a conventional internal magnetic shield.

[Explanation of symbols]

1 Front panel 2 funnel 3 envelope 4 phosphor screen 5 color selection electrode 6 electron gun 12 Clamping spring 13 frames 18 1st shield piece 19 Second shield piece 20 internal magnetic shield 21a, 22a First side wall 21b, 22b Second side wall 23a, 23b Coupling piece 24a, 24b coupling holes 141, 142, 143 Frame hole 151, 152 protrusions 161, 162, 163 Bottom hole 171, 172 Bottom wall 181, 191 long side wall 182, 192 Short side wall

Claims (6)

[Claims] 1. An envelope including a front panel and a funnel, an electron gun provided in a neck portion of the funnel, a phosphor screen formed on an inner surface of the front panel, and a phosphor screen opposed to the phosphor screen. Color selection electrode,
A cathode ray tube having a frame to which the color selection electrode is fixed and an internal magnetic shield fixed to the frame, wherein the internal magnetic shield is a first shield piece having a bottom wall fixed to the frame. A second shield piece, wherein the bottom wall of the first shield piece receives a force that keeps it away from the frame in the vicinity of an end thereof, while the bottom wall of the second shield piece has an end thereof. It receives a force such that it is crimped to the frame in the vicinity, and the end portions of the second shield pieces are overlapped on the end portions of the first shield piece to exert mutually opposite forces. A cathode ray tube characterized in that. 2. An envelope including a front panel and a funnel, an electron gun provided in a neck portion of the funnel, a phosphor screen formed on an inner surface of the front panel, and a phosphor screen facing the phosphor screen. Color selection electrode,
A cathode ray tube having a frame to which the color selection electrode is fixed and an internal magnetic shield fixed to the frame, wherein the internal magnetic shield is a first shield piece having a bottom wall fixed to the frame. A second shield piece, and a protrusion of the frame is provided in the vicinity of an end of the surface of the frame to which the bottom wall of the first shield piece is fixed, and the base is closer to the center than the protrusion. A bottom fixing portion for fixing the wall is provided, and a bottom fixing portion is provided near an end of the second shield piece on a surface of the second shield piece to which the bottom wall is fixed. A cathode ray tube, wherein a protrusion is provided near the center, and the end of the second shield piece overlaps the end of the first shield piece. 3. The first shield piece and the second shield piece each have a trapezoidal long side wall and a short side wall,
A first side wall of the first shield piece and a second side wall of the second shield piece, the first side wall continuing from the oblique side of the long side wall and the second side wall continuing from the oblique side of the short side wall. And the second side wall of the first shield piece and the first side wall of the second shield piece overlap each other, and a coupling piece is provided on the side wall of the first shield piece. The cathode ray tube according to claim 2, wherein the side wall of the piece is provided with a coupling hole into which the coupling piece is inserted. 4. The cathode ray tube according to claim 3, wherein the coupling piece is shaped like a tongue protruding from the side wall toward the electron gun. 5. The first shield piece and the second shield piece each have a trapezoidal long side wall and a short side wall,
A first side wall of the first shield piece and a second side wall of the second shield piece, the first side wall continuing from the oblique side of the long side wall and the second side wall continuing from the oblique side of the short side wall. Are overlapped with each other, the second side wall of the first shield piece and the first side wall of the second shield piece overlap with each other, and a coupling piece is provided on the side wall of the second shield piece. The cathode ray tube according to claim 2, wherein the side wall of the piece is provided with a coupling hole into which the coupling piece is inserted. 6. The cathode ray tube according to claim 5, wherein the coupling piece is in the shape of a tongue protruding from the side wall toward the front panel.