JP2001076639A - Inner magnetic shield forming member, inner magnetic shield, manufacture of the inner magnetic shield and cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an IMS with low cost which is provided with a means for completely shielding an unnecessary over scanned electron beam in a vertical direction (upper and lower sides). SOLUTION: An IMS 20 is structured in such a way that plate-shaped short side magnetic shield parts 23, that makes two slope parts of a short side and are continued each other are set at the one side of a plate-shaped long side magnetic shield part 22 that makes a slope part and an IBS part 24 is set at the other side of it so as to be integrally formed, and two of IMS formation members 21 which are integrally formed by upper beam shield(UBS) parts 25 parallelly opposed to a base of the long side magnetic shield 22 along a long side direction at the tip of the IBS part 24 are welded and integrated therewith.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a member for forming an internal magnetic shield, an internal magnetic shield using the member for forming an internal magnetic shield, a method of manufacturing the internal magnetic shield, and a method using the internal magnetic shield. Cathode ray tube (CRT)
About.

[0002]

2. Description of the Related Art An internal magnetic shield (IMS) for shielding terrestrial magnetism is required inside a cathode ray tube.
An inner beam shield (IBS) that blocks unnecessary electron beams going outside the effective screen is required. Some CRTs are provided with an IMS and an IBS independently of each other. However, in order to further reduce the price, a CRT in which the IMS and the IBS are integrated has been developed. FIG. 5 is an exploded perspective view of such a CRT.

In FIG. 1, 1 is a funnel, 2 is a neck portion of the funnel 1 in which an electron gun is built, and 3 is an IM.
S, 3l, 3l denote the long side magnetic shield portions of the IMS 3, 3s, 3s, 3s, 3s denote the short side magnetic shield portions of the IMS 3, and these magnetic shield portions 31, 3
1, 3s, 3s, 3s, and 3s are each inclined at a predetermined angle with respect to a plane perpendicular to the central axis of the CRT and have a predetermined geomagnetic shielding effect. The pair of short sides of the IMS 3 function as an IBS that blocks unnecessary electron beams that are overscanned in the horizontal direction. Therefore, the IMS 3 also has a function as an IBS.

[0004] Reference numeral 4 denotes an aperture grille structure, which comprises frames 5, 5 and 6, and an aperture grille 7 stretched between the frames 5.5. Reference numeral 8 denotes a glass panel to which the aperture grille structure 4 is attached. The IMS 3 is attached to the aperture grille structure 4 in a state where the IMS 3 is mounted on the aperture grille structure 4.
-It is located in a predetermined positional relationship between the funnels 1.

FIGS. 6A and 6B are plan views showing different IMS forming members 9a and 9b used for forming the conventional IMS 3, and FIG. 7 is an exploded perspective view of the same. The IMS forming members 9a and 9b are both formed by pressing a metal plate having magnetism, and one IMS 3 includes one IMS forming member 9a and two IMS forming members 9b and 9b. 6 and 7, the two-dot chain line is a bent portion, 10 and 10 are long side magnetic shield portions formed on the IMS forming member 9a, and 11, 11, 11, and 11 are IM.
The short side magnetic shield portions formed on the S forming members 9b, 9b. The IMS forming members 9a, 9b, 9b are bent at the respective bent portions, and the IMS forming members 9a
The IMS forming members 9b and 9b are fixed by, for example, welding. Then, the IMS 3 is configured as shown in the rear view of FIG. 8 and the perspective view of FIG. Then, the short side inner edges 12, 12 of the IMS forming member 9a function as an IBS portion of the IMS 3, and play a role of blocking an overscanned electron beam in horizontal scanning.

[0006]

The conventional IM
First, S3 includes an IBS for blocking an overscanned electron beam in the horizontal scanning, but does not have a function of completely blocking an unnecessary overscanned electron beam in the vertical scanning. 5 (see FIG. 5) has a problem that an electron beam hits and is reflected to cause halation. FIG. 10 is an explanatory diagram showing such a problem. In other words, an overscanned electron beam directed upward or downward from the long side magnetic shield portion 10 can be shielded, but as shown in FIG. In fact, the existing IMS 3 does not shield the electron beam passing through the area 13 in reality. As a result, halation could not be completely eliminated.

Second, the conventional IMS 3 requires as many as three IMS forming members, and further has one IMS forming member 9a and two other IMS forming members.
Since it has a shape different from that of the forming members 9b, 9b, two types of molding dies are required. Therefore, there is a problem that it is difficult to reduce the cost required for forming the IMS.

The present invention has been made to solve such a problem. In addition to an IBS for shielding an unnecessary electron beam that has been overscanned in the horizontal direction, the present invention has been made in the vertical direction (up and down). It is an object of the present invention to provide an IMS having a means for completely shielding an unnecessary electron beam overscanned at a low cost.

[0009]

According to a first aspect of the present invention, there is provided a member for forming an IMS, wherein one side of a plate-like long side magnetic shield portion serving as a slope portion has two short side slope portions connected to each other. An upper portion formed integrally with a short-side magnetic shield portion having a rectangular shape and an IBS portion on the other side, and a front end of the IBS portion facing the base of the long-side magnetic shield portion along the long side direction along the long side direction. A beam shield (UBS) portion is integrally formed.

Therefore, according to the IMS forming member of the first aspect, two IMS forming members are prepared,
One IMS can be obtained by connecting the S portion and the long side magnetic shield portions and also connecting the inner beam shield portion and the short side magnetic shield portions of each other,
The number of IMS forming members required to obtain an IMS can be reduced by one compared with the conventional one, and one IMS
Can be formed in exactly the same shape, and only one type of molding die is required to form the IMS forming member. Therefore, it is possible to reduce the number of materials, assembling man-hours, and the number of types of molds used for the IMS, thereby reducing the manufacturing cost of the IMS. In addition, since the number of members is small, the number of connection points can be reduced, so that the magnetic resistance of the magnetic circuit formed by the IMS can be made smaller than before.

Further, as in the conventional case, the IBS portion is provided on each short side, so that not only the horizontal overscan unnecessary electron beam can be shielded as in the conventional case, but also the unnecessary overscan in the vertical direction can be performed on each long side. Since there is a UBS portion for shielding the electron beam, the UBS portion can also shield a vertical overscan unnecessary electron beam, which cannot be conventionally performed.

In the IMS according to the second aspect of the present invention, the two IMS forming members are connected to each other at the UBS portion and the long side magnetic shield portions, and also at the mutual IBS portion and the short side magnetic shield portions. It is characterized by being done.

Therefore, according to the IMS of the present invention, since only two IMS forming members have the same shape, the number of materials, the number of required mold types,
The number of assembling steps can be reduced, and the manufacturing cost can be reduced. In addition, since the number of members is small, the number of connection points can be reduced, so that the magnetic resistance of the magnetic circuit formed by the IMS can be made smaller than before. Therefore, the magnetic shield effect can be further enhanced. Since each IMS forming member has a UBS portion, the UBS portion can shield a vertical direction overscan unnecessary electron beam, which cannot be conventionally performed.

According to a third aspect of the present invention, there is provided a method of manufacturing an IMS, comprising:
Two S forming members are prepared, each IMS forming member is bent so that each magnetic shield portion forms a slope portion, and the two IMS forming members are lengthened with each other's UBS portion. One IMS is obtained by connecting between the side magnetic shield portions and also between the IBS portion and the short side magnetic shield portions of each other.

Therefore, according to the IMS manufacturing method of the present invention, one IMS can be obtained with only two IMS forming members, and the IMS forming member has the same shape. The number of types of forming dies is only one, so that the number of materials, the number of types of dies, and the number of assembling steps can be reduced, and the manufacturing cost can be reduced. Moreover,
Since the number of parts is small, the number of connection points is small, so
The magnetic resistance of the magnetic circuit formed by the IMS can be made smaller than before, and the geomagnetic shield effect can be further enhanced. Since each IMS forming member has a UBS portion, the UBS portion can shield a vertical direction overscan unnecessary electron beam, which cannot be conventionally performed.

The CRT according to the fourth aspect is the IM according to the second aspect.
S is built-in. Therefore, C in claim 4
According to the RT, the effect enjoyed by the IMS of claim 2 can be obtained.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention basically relates to a short-side magnetic field which forms a short-side slope portion on one side of a plate-like long-side magnetic shield portion which becomes a long-side slope portion. A shield portion is integrally formed, and a plate-shaped IBS portion is integrally formed on the other side of the long side magnetic shield portion along a short side direction;
Two IMS forming members are integrally formed at the tip of the IBS portion and integrally formed with a plate-shaped IBS portion extending along the long side direction so as to face the long side magnetic shield portion. The members are bent so that each of the magnetic shield portions forms an inclined surface.
The forming member is connected by the UBS portion and the long side magnetic shield portion of each other and also by the IBS portion and the short side magnetic shield portion of each other to form one IMS,
The IMS is provided in, for example, an aperture grill type CRT.

The connection between the two IMS forming members may be made by welding or by caulking, regardless of the type of means.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments. 1A and 1B show an embodiment of the IMS of the present invention. FIG. 1A is an exploded perspective view, FIG. 1B is a perspective view, and FIG. FIG. 3 is a plan view of one IMS forming member, and FIG. 3 is a rear view of the IMS.
FIG. 4 is an explanatory diagram of one of the effects of the present invention that can remove unnecessary electron beams that are overscanned in the vertical direction.

In the drawing, reference numeral 20 denotes an IMS, which comprises two IMS forming members 21 and 21 having exactly the same shape. Each IMS forming member 21 is made of a metal plate having magnetism, one long side magnetic shield portion 22 and two short side magnetic shield portions 2 integrally formed with each other.
3, 23, an IBS portion 24 forming a short side, and a UBS portion 25 forming a long side and facing the long side magnetic shield portion 22. Thereafter, a portion indicated by a two-dot chain line At each magnetic shield part 22,
23, 23 are configured to form an inclined portion inclined at a predetermined angle.

That is, one end of two short side magnetic shield portions 23, 23 connected to one side (the left side in FIG. 2) of the long side magnetic shield portion 22 is integrally formed, One end of an IBS portion 24 extending in the short side direction is integrally formed on the other side (the right side in FIG. 2) of the side magnetic shield portion 22, and the other end of the IBS portion 24 extends in the long side direction and An IM shown in FIG. 2 in which one end of a UBS portion 25 facing the long side magnetic shield portion 22 is integrally formed.
The S forming member 21 is formed by press punching of a plate material, and is bent at a line indicated by a two-dot chain line in FIG. 2 so that each magnetic shield portion 22, 23, 23 is inclined at a predetermined angle with respect to the IMS forming member 21. Make a slope.

Then, two such IMS forming members 21 are prepared, and the two IMS forming members 21 are placed in the position (B) from the positional relationship shown in FIG. ), As shown in FIG.
By fixing the MS forming members 21 to each other, I
The MS 20 is fixed. Specifically, the bases (parts on the opposite side to the inner ends) of the short side magnetic shield portions 23 of one IMS forming member 21 are connected to the other IMS forming member 21.
Of the IBS portion 24 (the portion opposite to the inner end) and the long side magnetic shield portion 2 of one of the IMS forming members 21
2 by connecting the base (part opposite the inner end) to the base (part opposite the inner end) of the UBS portion 25
S20 is formed.

As shown in FIG. 4 (A-A in FIG. 3), the inner end of the IBS portion 24 not only blocks (shields) unnecessary electron beams overscanned in the horizontal direction as in the prior art.
As shown in the cross-sectional view along the line), the inner end of the inner beam shield portion 25 can block (shield) unnecessary electron beams that are overscanned in the vertical direction. That is, as shown in FIG. 4, an area which is not shielded in spite of an area where the unnecessary electron beam due to the vertical overscan passes and which needs to be shielded (electron beam shield required area 13, see FIG. 10) as shown in FIG. US
It can be shielded by the B portion 25.

The IMS 20 is used for a CRT instead of the IMS 3 in FIG. Although there is a difference in shape between the IMS 20 of the present embodiment and the conventional IMS 3 such as the presence or absence of the inner beam shield portion 25, the conventional IMS 3 and the IMS 20 can be viewed in the same shape at the viewing angle shown in FIG. The exploded perspective view of the CRT incorporating the CRT is not particularly described.

According to this embodiment, the IMS forming member 21
Can be composed of only two IMSs, so that the number of components of the IMS 20 can be reduced from the conventional three to two, and since the two members 21 are the same as each other, Only one type of mold is needed to form it. Therefore, the number of materials, the number of required mold types, and the number of assembling steps can be reduced, and the manufacturing cost can be reduced.

Moreover, since the number of members is small, the number of connection points is small, so that the magnetic resistance of the magnetic circuit formed by the IMS 20 can be made smaller than before, and the terrestrial magnetism shielding effect can be enhanced. And each I
Since the MS forming member 21 has the long-side UBS portion 25, the UBS portion 25 can also shield a vertical overscan unnecessary electron beam, which could not be conventionally performed.

[0027]

According to the IMS forming member of the first aspect,
Two IMS forming members are prepared and connected to each other at the inner beam shield part and the long side magnetic shield part and also at the mutual UBS part and the short side magnetic shield part to connect one IMS. You can get the IMS
The number of IMS forming members required to obtain
In addition to reducing the number of sheets, the two IMS forming members constituting one IMS can have exactly the same shape, and only one type of mold is required. Therefore, the IMS
Thus, the number of materials, the number of assembly steps, and the number of types of dies used in the above-mentioned steps can be reduced, and the manufacturing cost of the IMS can be reduced. In addition, since the number of members is small, the number of connection points can be reduced, so that the magnetic resistance of the magnetic circuit formed by the IMS can be made smaller than before.

Since a magnetic shield portion is provided on each short side as in the conventional case, not only can a horizontal overscan unnecessary electron beam be shielded as in the conventional case, but also a UBS portion can be provided on each long side. The UBS portion can shield a vertical overscan unnecessary electron beam, which cannot be conventionally performed.

According to the IMS of the second aspect, two IMSs
Since only the forming members are used and the IMS forming members have the same shape, the number of materials, the number of required molds, and the number of assembling steps can be reduced, and the manufacturing cost can be reduced. . In addition, since the number of members is small, the number of connection points can be reduced, so that the magnetic resistance of the magnetic circuit formed by the IMS can be made smaller than before. Since each IMS forming member has a UBS portion on the long side, the UBS portion can shield a vertical overscan unnecessary electron beam, which has not been conventionally possible.

According to the IMS manufacturing method of claim 3, 2
One IMS can be obtained with only one IMS forming member, and the IMS forming member has the same shape.
The number of types of MS forming member forming dies is only one, so that the number of materials, the number of dies, and the number of assembling steps can be reduced, and the manufacturing cost can be reduced. In addition, since the number of members is small, the number of connection points can be reduced, so that the magnetic resistance of the magnetic circuit formed by the IMS can be made smaller than before. Since each IMS forming member has a UBS portion on the long side, the magnetic shield portion can also shield a vertical overscan unnecessary electron beam, which could not be conventionally performed.

According to the CRT of the fourth aspect, the second aspect
Since the above IMS is used, the effects enjoyed by the IMS can be obtained.

[Brief description of the drawings]

FIGS. 1A and 1B show an embodiment of an IMS of the present invention, wherein FIG. 1A is an exploded perspective view and FIG. 1B is a perspective view.

FIG. 2 is a plan view of one IMS forming member constituting the IMS of the embodiment.

FIG. 3 is a rear view of the IMS shown in FIG. 1;

FIG. 4 is an explanatory diagram of one of the effects of the present invention that can remove unnecessary electron beams that are overscanned in the vertical direction.

FIG. 5 is an exploded perspective view of a CRT using an IMS.

6A and 6B are plan views showing different IMS forming members of a conventional example.

FIG. 7 is an exploded perspective view of a conventional IMS.

FIG. 8 is a rear view of a conventional IMS.

FIG. 9 is a perspective view of a conventional IMS.

FIG. 10 is a cross-sectional view taken along the line AA of FIG. 8, showing one of the problems of the conventional IMS.

[Explanation of symbols]

20 ... IMS, 21 ... IMS forming member, 22
... Long side magnetic shield part, 23 ... Short side magnetic shield part, 24 ... IBS part, 25 ... UB
S part.

Claims (4)

[Claims] 1. A plate-shaped short side magnetic shield portion serving as a short side slope portion is integrally formed on one side of a plate-shaped long side magnetic shield portion serving as a long side slope portion, On the other side of the long side magnetic shield part, a plate-shaped inner beam shield part is integrally formed along the short side direction, and at the tip of the inner beam shield part, along the long side direction along the long side direction. A member for forming an internal magnetic shield, wherein a plate-shaped upper beam shield portion extending so as to face the shield portion is integrally formed. 2. A long-side magnetic shield, wherein a short-side magnetic shield that forms a short-side slope is integrally formed on one side of a long-side magnetic shield that forms a long-side slope. On the other side of the portion, a plate-shaped inner beam shield portion is integrally formed along the short side direction, and the front end of the inner beam shield portion faces the base of the long side magnetic shield portion along the long side direction. The two internal magnetic shield forming members are integrally formed with a plate-shaped upper beam shield portion extending so that the upper magnetic shield portion is formed integrally with the upper beam shield portion. Characterized in that the inner magnetic shield is connected between the long side magnetic shield portions and between the one inner beam shield portion and the other short side magnetic shield portion. . 3. A plate-like short-side magnetic shield portion serving as a short-side slope portion is integrally formed on one side of a plate-like long-side magnetic shield portion serving as a long-side slope portion; A plate-shaped inner beam shield portion is integrally formed on the other side of the long side magnetic shield portion along the short side direction, and the tip of the inner beam shield portion is formed along the long side direction along the long side direction. Two internal magnetic shield forming members are integrally formed with a plate-shaped upper beam shield portion extending so as to face the shield portion, and each of the internal magnetic shield forming members is bent by bending each of the internal magnetic shield forming members. The two internal magnetic shield forming members are connected to each other at one upper beam shield portion and the other long side magnetic shield portion and at one side. Emissions donor beam shield portion and a manufacturing method of the internal magnetic shield, characterized in that to produce a single internal magnetic shield and connected by shorter side magnetic shield portions together. 4. The long-side magnetic shield, wherein a short-side magnetic shield portion forming a short-side slope portion is integrally formed on one side of the long-side magnetic shield portion forming a long-side slope portion. On the other side of the portion, a plate-shaped inner beam shield portion is integrally formed along the short side direction, and the tip of the inner beam shield portion is opposed to the long side magnetic shield portion along the long side direction. The two internal magnetic shield forming members are formed integrally with each other, and the two internal magnetic shield forming members are formed of one upper beam shield portion and the other having the same length. It has a special feature that it has an internal magnetic shield connected between the side magnetic shield parts and between one inner beam shield part and the other short side magnetic shield part. The cathode ray tube to be featured.