JP3312518B2 - Internal magnetic shield, method of manufacturing the same, and cathode ray tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention is, shadow, such as color TV
Internal electron shield (IB) used for a cathode ray tube (CRT)
The present invention relates to an inner magnetic shield (IMS) integrally provided with an S (Inner Beam Shield), a manufacturing method thereof, and a cathode ray tube .

[0002]

2. Description of the Related Art Inside a CRT, an IMS for shielding terrestrial magnetism and an unnecessary electron beam outside the effective screen of the CRT are cut off, or the unnecessary electron beam strikes a frame of a color selection mechanism and is reflected on the effective screen. An IBS is provided to prevent this from happening.

[0003] Conventional CRTs include those in which an IMS and an IBS are independently mounted, and those in which an IMS having the function of an IBS is also mounted. FIGS. 8, 9 and 10 are external perspective views of an IMS used for a conventional CRT, which does not have a function as an IBS by itself. The IMS 1 shown in FIG. 8 has an aperture-integrated shape. The IMS 2 shown in FIG. 9 is manufactured by joining pieces 2a and 2b formed by cutting and folding a single thin plate at a joint 15 by welding or caulking.
In the IMS 3 shown in FIG. 10, the A parts 4a and 4b and the B parts 5a and 5b formed by cutting a thin plate as shown in FIG. 10 (A) at the joint 6 as shown in FIG. 3 (B). It is manufactured by welding or caulking.

FIGS. 11 and 13 are external perspective views of an IMS having a function as an IBS used in a conventional CRT. The IMS 7 shown in FIG. 11 is manufactured by joining parts 7a and 7b formed by cutting and folding a thin plate as shown in FIG.
The IMS 7 is integrally formed with an IBS unit 8. The IMS 11 shown in FIG. 13 includes A parts 12a and 12b,
B parts 13a, 13b and IBS parts 14a, 14b are joined together by welding or caulking.

[0005]

However, in the above-described CRT using the IMS 1, 2, 3 shown in FIGS. 8, 9, and 10, it is necessary to separately provide an IBS, and there is a problem that the price is increased. . Further, the IMS 7 shown in FIG. 11 can be reduced in cost by providing the IBS unit 8, but it is necessary to connect the parts 7a and 7b in the manufacturing process, and the workability is poor. Further, the IMS shown in FIG.
11 or IMS disclosed in JP-A-6-124661.
Now, A parts 12a and 12b and B parts 13a and 13
b and the IBSs 14a and 14b are welded and joined, which causes a problem that the manufacturing process is complicated and the price is high.
In the IMS 11, when a plurality of IMSs are loaded at the time of transportation or the like, the IBSs 14a and 14b and the B parts 13
a and 13b are engaged with each other, so that adjacent IMSs cannot be stacked in close proximity to each other, resulting in a problem of poor loading efficiency.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to provide an internal magnetic shield which can be manufactured at a low cost and has good workability including loading efficiency and a method of manufacturing the same. .

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems of the prior art and to achieve the above-mentioned object, the present inventor has proposed that the position of the present invention be substantially symmetrical with respect to the central axis in the longitudinal direction. When the internal magnetic shield means composed of the first piece and the second piece is used, in addition to the first piece and the second piece as in the related art, the central axis in the short direction is used. The characteristics as an IMS are equal to or better than the case where the internal magnetic shield means composed of the third piece and the fourth piece located substantially symmetrically with respect to Was found.

In addition, since the internal magnetic shield means is constructed as described above, the internal magnetic shield means and the internal electron beam shield piece are cut and folded into one piece without welding or caulking. It is possible to reduce the cost and improve the workability. Further, by forming the internal magnetic shield means and the internal electron beam shield piece so as not to overlap in the front direction, the loading efficiency was improved.

That is, the internal magnetic shield of the present invention
An inner magnetic shield means for blocking the influence of a magnetic field inside the cathode ray tube, comprising a first piece and a second piece located substantially symmetrically with respect to a central axis in the longitudinal direction; An internal electron beam shield piece positioned orthogonal to the first piece and the second piece so as not to overlap with the internal magnetic shield means, and for blocking unnecessary electron beams outside the effective screen; Is formed integrally by cutting and folding a single plate.

In the internal magnetic shield according to the present invention, preferably, the internal magnetic shield means engages with the first piece and the second piece with respect to a central axis in a lateral direction. And a third piece and a fourth piece which are symmetrically positioned. As described above, by further including the third piece and the fourth piece, the characteristics as the IMS can be improved.

Further, the internal magnetic shield of the present invention preferably further has a locking portion for keeping a distance between adjacent internal magnetic shields constant when a plurality of internal magnetic shields are stacked. Thus, by providing the locking portion, when a plurality of internal magnetic shields are stacked, it is possible to avoid that adjacent internal magnetic shields come into close contact with each other, so that the internal magnetic shields can be easily removed. Become.

Further, in the internal magnetic shield according to the present invention, preferably, the internal electron beam shield piece is formed by bending the tip so as to face the electron gun.

In the internal magnetic shield according to the present invention, preferably, the internal electron beam shield piece is formed by bending a tip thereof in two steps. In this manner, by bending the tip in two steps, it is possible to effectively prevent the electron beam inside the cathode ray tube from hitting the internal electronic shield and being output toward the aperture grille structure. Further, the cathode ray tube of the present invention
Has the above-described internal magnetic shield.

Further, the method for manufacturing an internal magnetic shield according to the present invention comprises a first piece and a second piece which are located substantially symmetrically with respect to the central axis in the longitudinal direction, and the magnetic field inside the cathode ray tube is reduced. Internal magnetic shielding means to block the effects;
An internal electron for orthogonally intersecting the first piece and the second piece so as not to overlap with the internal magnetic shield means in the front direction and for blocking unnecessary electron beams outside the effective screen. The wire shield piece is formed integrally by cutting and folding one plate.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an internal magnetic shield (IMS), a method of manufacturing the same, and a cathode ray tube according to an embodiment of the present invention will be described. First Embodiment FIG. 1 is an external perspective view of an IMS 20 according to the first embodiment . As shown in FIG. 1, the IMS 20 has internal magnetic shield portions 21a and 21a as a first piece and a second piece.
b, internal electronic shield parts 22a, 22b, mounting part 23,
It has a main body part 25 and a long side plate eave 26, and a concave part 24 is formed in the main body part 25.
A protrusion 27 is locked to 6. IMS 20 is a CRT
In FIG. 2, as shown in FIG. 2, between the funnel 20 and the aperture grille structure 10, it is provided fixed to the aperture grille structure 10. The aperture grille structure 10 is fixed to the panel 31. As shown in FIG. 3, the IMS 20 is formed by punching a single thin plate by pressing or the like to form a punched portion 40, and then cutting and folding (bending) the remaining portion to form one piece. There is no need to perform welding or caulking in the process. At this time, the IMS 20 is manufactured by processing a single thin plate with a plurality of press working machines, for example, in a flow operation, or by using a single press capable of performing a plurality of press workings. The press working is performed, for example, about five times before the IMS 20 is manufactured from the thin plate.

The internal magnetic shield portions 21a and 21b are formed by cutting and folding the thin plate shown in FIG. 3 by press working or the like, are symmetrically positioned with respect to a central axis along the long side direction, and are bent at both ends of one side. It has a recess 21a1. The internal magnetic shield portions 21a and 21b have a function of shielding terrestrial magnetism.

The internal electronic shield portions 22a and 22b are formed by cutting and folding the thin plate shown in FIG. 3, are located symmetrically with respect to the central axis along the short side direction, and are unnecessary outside the effective screen of the CRT. It has a function of blocking the electron beam or preventing unnecessary electron beams from hitting the frame of the color selection mechanism and being reflected on the effective screen. The internal electronic shield portions 22a and 22b are provided with the bent portions 21 in the front direction.
It is formed so as not to overlap with the internal magnetic shield portions 21a and 21b including a1.

By setting the positional relationship between the internal magnetic shield portions 21a and 21b and the internal electronic shield portions 22a and 22b as described above, when a plurality of IMSs 20 are stacked, the internal magnetic shield portions 21a and 21b of the adjacent IMS 20 are mounted.
And the internal electronic shield portions 22a and 22b can be located close to each other. Therefore, IMS
According to 20, it is possible to prevent the IMSs 14a, 14b and the B parts 13a, 13b from engaging with each other as in the IMS 11 shown in FIG.

FIG. 4 is a graph showing the relationship between IM and X-rays shown in FIG.
It is a fragmentary sectional view of S20. As shown in FIG.
The electronic shield part 22a is formed so as to be bent with respect to the main body part 25 in a direction opposite to the direction of the internal magnetic shield parts 21a and 21b shown in FIG. The electronic shield part 22b is the electronic shield part 22
Same as a. For example, as shown in FIG. 4B, the electronic shield part 22 a is formed so as to be bent in the direction of the internal magnetic shield parts 21 a and 21 b (the direction of arrow B) with respect to the main body part 25. Alternatively, as shown in FIG. 4 (C), it may be formed by two-step bending in which the main body 25 is bent in the direction of arrow A and the distal end is bent in the direction of arrow B. Good. In this manner, by bending the tip in two steps, it is possible to effectively prevent the electron beam inside the cathode ray tube from hitting the internal electronic shield and being output toward the aperture grille structure.

The mounting portion 23 is formed by cutting and folding the thin plate shown in FIG. 3 and is formed so as to be bent as shown in FIG. 4A, and is formed on the mounting portion 26 of the aperture grille structure. Fixed.

The long-side plate-like eaves 26 are formed by cutting and folding the thin plate shown in FIG. 3, and are located symmetrically with respect to the central axis in the long-side direction, and have convex portions 27 formed at predetermined positions. . The convex portion 27 is formed by press working or the like, and as shown in FIG.
Substantially the entire surface of S20 is prevented from being in close contact with another IMS 20, and plays a role of facilitating removal of IMS 20.

The recesses 24 are formed at the four corners of the main body 25 by press working, for example, and serve to increase the strength. A convex portion may be provided instead of the concave portion 24.

As described above, the IMS 20 is manufactured by cutting and folding one thin plate using press working or the like.
Therefore, the manufacturing process is simple, and the manufacturing cost can be reduced. Further, the IMS 20 includes an internal electronic shield unit 22.
a, 22b, IBS and IM
S can perform both functions. Therefore, IM
If S20 is used for a CRT, it is not necessary to separately attach an IBS. For example, the manufacturing cost of the CRT can be reduced because an IBS manufacturing apparatus is not required.

Also, in the IMS 20, from a prototype or the like,
The characteristics are improved as compared with the conventional IMS. FIG.
A CRT using the IMS 20 according to the present embodiment and a conventional IRT
C used when comparing characteristics with CRT using MS
FIG. 7 is a diagram showing positions for comparing characteristics on an effective screen of RT. That is, the mislanding amount due to the terrestrial magnetism is the terrestrial pp value (μ) at the point A (Y end) shown in FIG.
m) is “48” in the IMS 20 and “47” in the conventional IMS, which is almost the same characteristic. On the other hand, the amount of mislanding due to terrestrial magnetism is shown in FIG.
At the point (corner), the ground pp value (μm) is
While MS20 is "39", conventional IMS is "67", and IMS20 has very good characteristics.

Further, with the IMS 20, a high loading efficiency can be obtained, and the removal after loading is easy.

Second Embodiment FIG. 6 is an external perspective view of an IMS 30 according to the second embodiment . As shown in FIG. 6, the IMS 30 is different from the IMS 20 shown in FIG.
B-parts 31a and 31b are inserted into the fold 21a1 of the 21b.
Are fixed using welding or caulking. The B parts 31a and 31b are shaped so as not to overlap with the internal electronic shield parts 22a and 22b on the front side of the IMS 30.

If the IMS 30 is used, for example, in a large tube or the like where the influence of unnecessary electron beams outside the effective screen of the CRT is relatively large, such an influence can be effectively suppressed.

[0028]

As described above, according to the internal magnetic shield of the present invention, a higher characteristic can be obtained as an IMS as compared with the conventional internal magnetic shield. According to the internal magnetic shield of the present invention, it is manufactured by cutting and folding one thin plate using press working or the like. Therefore, the manufacturing process is simple, and the manufacturing cost can be reduced. According to the internal magnetic shield of the present invention, the IBS and I
Both MSs can perform the function. Therefore, if the internal magnetic shield of the present invention is used for a CRT,
It is not necessary to attach S, and for example, the manufacturing cost of the CRT can be reduced because an IBS manufacturing apparatus is not required. Further, according to the internal magnetic shield of the present invention, high loading efficiency can be obtained, and further, removal after loading is easy. Further, according to the internal magnetic shield of the present invention, such an effect can be effectively suppressed when used for a large tube or the like where the influence of unnecessary electron beams outside the effective screen of the CRT is relatively large. In addition, the present invention
According to the cathode ray tube, the influence of unnecessary electron beams can be reduced.
And high-quality images can be provided.

[Brief description of the drawings]

FIG. 1 is an external perspective view of an IMS according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of a CRT using the IMS shown in FIG.

FIG. 3 is a development view for explaining a method of manufacturing the IMS shown in FIG. 1;

FIG. 4 is a cross-sectional view of the IMS taken along line XX shown in FIG.

FIG. 5 is a cross-sectional view for explaining a state when a plurality of IMSs shown in FIG. 1 are stacked.

FIG. 6 is an external perspective view of an IMS according to a second embodiment of the present invention.

FIG. 7 is a diagram for explaining characteristics of mislanding due to terrestrial magnetism in the IMS according to the present invention.

FIG. 8: Conventional aperture-integrated IMS (without IBS function)
It is an external appearance perspective view for explaining.

FIG. 9 is an external perspective view for explaining a conventional two-piece IMS (without an IBS function).

FIG. 10 is an external perspective view for explaining a conventional four-piece IMS (without the IBS function).

FIG. 11 is an external perspective view for explaining a conventional two-piece IMS (with an IBS function).

FIG. 12 is a development view for explaining a method of manufacturing the IMS shown in FIG. 11;

FIG. 13 is an external perspective view for explaining a conventional 6-piece IMS (with an IBS function).

[Explanation of symbols]

 Reference Signs List 20 IMS 21a and 21b Internal magnetic shield 22a and 22b Internal electronic shield 23 Mounting part 24 Depression 25 Body part 26 Long plate eaves 27 Projection

Claims (7)

(57) [Claims] 1. An internal magnetic shield means, comprising a first piece and a second piece located substantially symmetrically with respect to a central axis in a longitudinal direction, for shielding an influence of a magnetic field inside a cathode ray tube. An inner portion for intercepting an unnecessary electron beam outside the effective screen so as not to overlap with the inner magnetic shield means in the front direction so as to be orthogonal to the first piece and the second piece; An internal magnetic shield formed integrally with an electron beam shield by cutting and folding a single plate. 2. The internal magnetic shield means engages with the first piece and the second piece while providing a third piece symmetrically positioned with respect to a central axis in a lateral direction. The internal magnetic shield of claim 1, further comprising a fourth piece. 3. The internal magnetic shield according to claim 1, further comprising a locking portion for maintaining a constant distance between adjacent internal magnetic shields when a plurality of internal magnetic shields are stacked. 4. The internal magnetic shield according to claim 1, wherein the internal electron beam shield piece is formed by bending the tip so as to face the electron gun. 5. The internal magnetic shield according to claim 1, wherein the internal electron beam shield piece is formed by bending a tip in two steps. 6. The internal magnet according to claim 1, wherein :
A cathode ray tube having a shield . 7. An internal magnetic shield means, comprising a first piece and a second piece located substantially symmetrically with respect to a central axis in a longitudinal direction, for shielding an influence of a magnetic field inside the cathode ray tube. An inner portion for intercepting an unnecessary electron beam outside the effective screen so as not to overlap with the inner magnetic shield means in the front direction so as to be orthogonal to the first piece and the second piece; A method for manufacturing an internal magnetic shield in which an electron beam shield piece and a single plate are cut and folded to be integrally formed.