JP2003168375A - Internal magnetic shield for cathode-ray tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an internal magnetic shield for a cathode-ray tube capable of preventing deformation in a frame shield part even in a form where a plurality of the shield are stacked. <P>SOLUTION: This internal magnetic shield 1 for a cathode-ray tube is attached to a mask structure 5 of the cathode-ray tube. In the periphery of a shield body 2 in each magnetic shield 1, a claw-like frame shield part 3 for shielding a frame 7 of the mask structure 5 is projected outside the shield body 2 at a predetermined bent angle θ°. In the circumferential part of each shield body 2, a space setting body 4 for imparting a predetermined space X between the adjacent magnetic shields 1, 1 with a plurality of magnetic shields 1 stacked is formed. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inner magnetic shield (hereinafter referred to as "Iner Magnetic Shield") mounted on a mask structure in a color cathode ray tube (hereinafter also referred to as CRT).
(Also referred to as MS).

[0002]

2. Description of the Related Art In a CRT, an electron beam emitted from an electron gun emits light by hitting a fluorescent screen formed on the inner surface of a face panel. A spreading type mask structure is arranged between the fluorescent screen and the electron gun, and the emitted electron beam passes through the through hole of the mask structure so that the electron beam hits the desired fluorescent substance on the fluorescent screen correctly. Is being done. However, since the electron beam is affected by the geomagnetism and the like, it tends to hit a position deviated from the desired phosphor, which causes the color purity of the screen to deteriorate. Therefore, an IMS is attached to the mask structure by welding or the like as a measure for improving the color purity deterioration due to the influence of the earth's magnetism or the like and performing good color selection.

The expansion type mask structure described above includes an aperture grill having a plurality of slits arranged adjacent to each other.
It is welded to and supported by a frame composed of a pair of upper and lower horizontal side members and a pair of left and right vertical side members.

As shown in FIG. 5, the IMS is a shield body 2 in which a ferromagnetic metal plate containing iron as a main component and having a thickness of about 0.1 to 0.3 mm is formed in a box shape of a quadrangular pyramid, and this shield. The main body 2 includes a plurality of claw-shaped frame shield portions 3 protruding from the periphery of the base end. By fixing the frame shield portion 3 to a pair of upper and lower lateral members of the frame of the mask structure by welding or the like, the IMS 1 is attached to the mask structure so as to surround the electron beam incident on the mask structure. FIG. 5 shows a state in which a plurality of IMSs 1 having the above configuration are stacked.

[0005]

However, since the IMS 1 is made of a very thin metal plate, it is likely to be deformed during transportation or during unpacking work, and the plurality of frame shield parts 3 in the IMS 1 as shown in FIG. Particularly easy to deform when stacked.

That is, FIG. 5 is used for transportation and storage.
In the state where a plurality of IMSs 1 having the same shape are stacked as shown in the above, the outermost frame shield part 3 (uppermost side in FIG. 5) is formed.
In addition, a simple calculation applies a force of the plate thickness of the frame shield part 3 x the number of stacked pieces / 2 minutes to the outer side, and the same force is applied to the innermost (the bottom side in FIG. 5) frame seal part 3 to the inner side. Join. And the force applied to the IMS 1 in this way is
When the elastic region of the ferromagnetic metal plate, which is the material of the IMS 1, is exceeded, the frame shield portion 3 is plastically deformed toward the outside or inside as shown by the chain line in FIG. As a result, when welding the IMS 1 to the frame of the mask structure,
Frame shield part 3 deformed to fall inward
Contacts the frame of the mask structure and causes welding defects. Further, in the IMS 1 in which the frame shield portion 3 is deformed in a state of falling outward, in an extreme case, the welding electrode does not hit the frame shield portion 3 and a problem such that welding cannot be performed occurs.

Therefore, it is an object of the present invention to provide an internal magnetic shield for a cathode ray tube which does not cause deformation of the frame shield portion even when a plurality of them are stacked.

[0008]

An internal magnetic shield for a cathode ray tube according to claim 1 of the present invention is an internal magnetic shield mounted on a mask structure of a cathode ray tube, and the mask is provided on the periphery of the shield body. A claw-shaped frame shield portion that shields the frame of the structure is provided to project outward from the shield body with a bending angle, and a plurality of the internal magnetic shields are stacked and adjacent to each other. A gap setting body that provides a predetermined gap between the shield bodies is provided around the shield body.

An inner magnetic shield for a cathode ray tube according to a second aspect of the present invention is the inner shield according to the first aspect, wherein the inner shield plate thickness is t, the bending angle of the frame shield portion is θ, and the gap is When X is set, the gap setting body may be formed to have a relationship of X> t / tan (θ-90).

According to a third aspect of the present invention, in the internal magnetic shield for a cathode ray tube according to the first aspect, the inner shield plate thickness is t, the bending angle of the frame shield part is θ, and the gap is When X is set, the bending angle may be formed to have a relationship of θ> t / tan ⁻¹ (t / X) +90.

In the internal magnetic shield for a cathode ray tube according to claim 4 of the present invention, a plurality of the gap setting bodies may be formed in the peripheral portion of the shield body.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below with reference to the drawings showing the embodiments thereof. The same or equivalent members as those in the conventional example shown in FIG. 5 are designated by the same reference numerals.

<Embodiment 1> FIG. 4 is a perspective view of a mask structure of an expanding type of a color cathode ray tube to which an IMS according to Embodiment 1 of the present invention is attached. The mask structure 5 is arranged between the fluorescent surface on the inner surface of the face panel of the color cathode ray tube and the electron gun, and regulates the electron beam so that the electron beam emitted from the electron gun hits a desired fluorescent material on the fluorescent surface. A device, an aperture grill 6
And a frame 7 that supports the aperture grill 6 in a stretched state.

The aperture grill 6 has a plurality of slits 8 arranged side by side in a certain direction, and a grit element body 9 formed between the adjacent slits 8 and 8.
The slit 8 and the grit element body 9 in the aperture grill 6 are formed by, for example, chemically etching a thin metal plate.

The frame 7 is composed of a pair of upper and lower lateral side members 1.
0a, 10b and a pair of left and right vertical side members 11a, 11b. The pair of upper and lower lateral side members 10a and 10b are members that are curved in an arc shape toward the tension side of the aperture grill 6, and have a L-shaped cross section perpendicular to the longitudinal direction. The pair of left and right vertical side members 11a and 11b are made of elastic members, and are attached between the pair of upper and lower horizontal side members 10a and 10b.

FIG. 3 shows an IM according to the first embodiment of the present invention.
It is a perspective view showing the state where S1 was attached to the mask structure 5. This IMS 1 has iron as a main component and a thickness of 0.
Made of a ferromagnetic metal plate of about 1 to 0.3 mm,
A box-shaped shield body 2 in the shape of a quadrangular pyramid, and a plurality of claw-shaped frame shield portions projecting outward from the shield body 2 at a predetermined bending angle θ ° on the periphery of the shield body 2. 3 and 3. The frame shield part 3
The IMS 1 is integrated with the mask structure 5 so that the shield body 2 covers the electron beam incident on the mask structure 5 by being fixed to the pair of upper and lower horizontal side members 10a and 10b of the frame 7 in the mask structure 5 by welding or the like. It is attached. The frame shield part 3 plays an influence of an external magnetic field, particularly a role of preventing deterioration of color purity due to a magnetic field in the tube axis direction of the color cathode ray tube, and a role of integrating the IMS 1 with the mask structure 5, and is indispensable. It is a thing.

FIG. 1 shows an IMS 1 according to the first embodiment.
Shows a state in which a plurality of are stacked. In the peripheral portion of the shield body 2 in the IMS 1, a predetermined gap X (mm) is provided between the adjacent IMS 1 and 1 in a stacked state as shown in FIG.
There are provided a plurality of gap setting bodies 4 each having a gap. Here, as the gap setting body 4, a protrusion is formed on a welding margin prepared for assembling the IMS 1 by drawing or folding.

The bending angle θ ° of the frame shield portion 3 in the IMS 1 is an angle of 90 ° or more with a plane including the peripheral portion of the shield body 2 as a reference plane. If the thickness of the ferromagnetic metal plate that is the material of IMS1 is t (mm), then IM
The gap X (mm) in the stacked state of S1 is X
> T / tan (θ-90). That is, for example, as shown in FIG. 2, the thickness t of the ferromagnetic metal plate which is the material of the IMS 1 is 0.2 mm, and the bending angle θ ° is 97 due to the restriction on the manufacturing apparatus of the color cathode ray tube.
When set to 0, the gap X is X> 0.
It is set to be 2 / tan (97-90), that is, 1.7 mm or more.

In the IMS 1 configured as described above, even if a plurality of IMS 1 are stacked for transportation and storage as shown in FIG.
Frame shield parts 3, 3 between adjacent IMS 1, 1
Since they do not come into contact with each other, the frame shield portion 3 is not deformed, and it is possible to avoid the occurrence of welding failure or welding failure when attaching to the mask structure 5.

<Second Embodiment> In the second embodiment,
In the IMS 1 according to the first embodiment, the plate thickness is t
(Mm), where the gap is X (mm), the bending angle θ ° of the frame shield portion 3 is θ> t / tan-1.
It is set to be (t / X) +90. That is, for example, the plate thickness of the IMS 1 is 0.2 mm, and the gap setting body 4 is set such that the gap X (mm) between the adjacent IMS 1 and 1 in the stacked state is 1.5 mm depending on the packing conditions.
Is provided, the bending angle θ of the frame shield portion 3
The angle θ is set so that θ> tan−1 (0.2 / 1.5) +90, that is, 97.6 ° or more.

Even in the IMS 1 configured as described above, when a plurality of IMS 1 is stacked for packing, as shown in FIG. The portion 3 is not deformed, and it is possible to avoid the occurrence of welding failure or welding failure when attaching to the mask structure 5.

[0022]

The internal magnetic shield for a cathode ray tube according to the first aspect of the present invention is an internal magnetic shield mounted on a mask structure of a cathode ray tube, and shields the frame of the mask structure around the periphery of the shield body. A claw-shaped frame shield portion is provided to project outward from the shield body with a bending angle, and in a state where a plurality of the internal magnetic shields are stacked, a predetermined gap is provided between the adjacent internal magnetic shields. Since the gap setting body for providing a gap is provided in the peripheral portion of the shield body, even when a plurality of stacked bodies are stacked, the frame shield portion is not deformed, and is attached to the mask structure. It is possible to avoid the occurrence of welding failure or welding failure.

An inner magnetic shield for a cathode ray tube according to a second aspect of the present invention is the inner shield according to the first aspect, wherein the inner shield plate thickness is t, the bending angle of the frame shield portion is θ, and the gap is X. At this time, since the gap setting body is formed to have a relationship of X> t / tan (θ-90), the variables (t, θ, X) can be easily adjusted according to the application by the above formula. It is possible to estimate.

According to a third aspect of the present invention, there is provided an internal magnetic shield for a cathode ray tube, comprising:
When the thickness of the inner shield plate is t, the bending angle of the frame shield portion is θ, and the gap is X, the bending angle has a relationship of θ> t / tan ⁻¹ (t / X) +90. Since it is formed on the
It is possible to easily estimate the bending angle θ in the state in which is fixed.

In the inner magnetic shield for a cathode ray tube according to the invention of claim 4, since the plurality of gap setting bodies are formed in the peripheral portion of the shield body, the inner magnetic shields are stacked more firmly and stably. be able to.

[Brief description of drawings]

FIG. 1 is a front view showing a state in which a plurality of internal magnetic shields for a cathode ray tube according to Embodiment 1 of the present invention are stacked.

FIG. 2 is a partial enlarged cross-sectional view showing a stacked state of the internal magnetic shield.

FIG. 3 is a perspective view showing a state in which the internal magnetic shield is attached to a mask structure.

FIG. 4 is a perspective view showing a mask structure of a spreading type to which the inner magnetic shield is attached.

FIG. 5 is a front view showing a state in which a plurality of conventional internal magnetic shields are stacked.

[Explanation of symbols]

1 internal magnetic shield (IMS), 2 shield body,
3 frame shield part, 4 interval setting body, θ ° bending angle, X gap, t plate thickness.

Claims (4)

[Claims] 1. An internal magnetic shield mounted on a mask structure of a cathode ray tube, wherein a claw-shaped frame shield portion for shielding the frame of the mask structure is provided on the outer periphery of the shield main body at the periphery of the shield main body. A gap setting body is provided around the shield body so as to have a predetermined gap between the adjacent inner magnetic shields in a state where the plurality of inner magnetic shields are stacked in a projecting manner with a bending angle. An internal magnetic shield for a cathode ray tube, which is provided in the section. 2. The inner shield according to claim 1, wherein when the inner shield plate thickness is t, the bending angle of the frame shield part is θ, and the gap is X, the gap setting body is X> t. The internal magnetic shield for a cathode ray tube according to claim 1, wherein the internal magnetic shield is formed to have a relationship of / tan (θ-90). 3. The inner shield according to claim 1, wherein the inner shield plate thickness is t, the bending angle of the frame shield portion is θ, and the gap is X, the bending angle is θ> t / The internal magnetic shield for a cathode ray tube according to claim 1, wherein the internal magnetic shield has a relationship of tan ^-1 (t / X) +90. 4. The internal magnetic shield for a cathode ray tube according to claim 1, wherein a plurality of the gap setting bodies are formed in a peripheral portion of the shield body.