JPH03213086A - Picture display device - Google Patents

Abstract

PURPOSE:To reduce a magnetic field to be leaked from a deflected yoke by providing a magnetic shield cover to surround the above mentioned deflected yoke from the outside and to shield the magnetic field to be leaked from the deflected yoke at a picture display device arranging the deflected yoke composed of a deflection coil and a core in the external part. CONSTITUTION:A deflected yoke 8 is surrounded by a magnetic shield cover 14. Therefore, the magnetic field to be leaked from the deflected yoke is shielded by the shield cover and is not leaked to the external part. Thus, for the picture display device without the shield cover 14 to be shown in a figure, a leaked magnetic field 15 is propagated to a distant place. In respect to this above mentioned example, for the device surrounded by the shield cover 14, the leaked magnetic field is shielded and the amount of the magnetic field to be leaked to the external part can be reduced.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an image display device, and more particularly to an image display device that prevents leakage magnetic fields generated from a deflection yoke attached to a cathode ray tube. .

[Conventional technology]

FIG. 9 shows an external view of a conventional cathode ray tube. In the figure, 1 is a cathode ray tube with a phosphor film 2 coated on the inner surface of the panel face, 3 is a panel, and 4 is a funnel integrally formed with the panel 3. , 5 indicates the neck portion. 6 is the neck part 5
7 is an electron gun 6 that generates an electron beam.
8 is a deflection yoke that deflects the electron beam from the electron gun 6.

As shown in FIG. 10, the deflection yoke 8 is composed of horizontal deflection coils 9a and 9b and a vertical deflection coil 10a10b, and the vertical deflection coil 10a10b is formed using a core 11 in a toroidal shape. In addition, the horizontal deflection coil 9
As shown in FIG. 11, a and 9b are loop-shaped and saddle-shaped.

In the cathode ray tube configured as described above, in FIG. 9, the electron beam emitted from the electron gun 6 is deflected to a predetermined position on the phosphor film 2 on the inner surface of the panel face by applying a deflection magnetic field by the deflection yoke 8. to display the image.

Here, the operation of the deflection yoke 8 will be explained in detail with reference to FIG. 12. In order to vertically deflect the electron beam emitted from the electron gun 6, the deflection yoke 8 must be deflected horizontally to generate a magnetic field in the directions 12a and 12b. The current is passed through the vertical deflection coil 10a.
, 10b, and in order to deflect the electron beam horizontally, it is necessary to flow a deflection current through the coils 9a, 9b to generate a magnetic field in the vertical direction 13a, 13b.

[Problem to be solved by the invention]

Incidentally, in recent cathode ray tubes, there is a strong demand for higher image resolution and higher density display, and as an example of this, the frequency of the horizontal deflection current has been increased. The deflection magnetic field generated by this high-frequency current not only deflects the electron beam inside the deflection yoke, but also occurs outside as a leakage magnetic field. This leakage magnetic field has the problem of not only having an adverse effect on nearby equipment, but also being harmful to humans and animals.

This invention was made to solve the above-mentioned problems, and its purpose is to obtain an image display device equipped with a cathode ray tube that can effectively reduce the leakage magnetic field generated from the deflection yoke. do.

[Means to solve the problem]

An image display device according to the present invention includes an electron gun and a fluorescent screen inside a cathode ray tube, and a deflection cork consisting of a deflection coil and a core is disposed outside. A magnetic shield cover is provided to shield magnetic field leakage from the deflection yoke.

[For production]

In this invention, since the deflection yoke is surrounded by the magnetic shield cover, the leakage magnetic field generated from the deflection yoke is shielded by the shield cover and does not leak to the outside.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. 1st
The figure shows an external view of a cathode ray tube as an image display device according to the present invention, and FIG.
1 is the same as the cathode ray tube explained in the conventional example, so the same reference numerals are given and the explanation will be omitted. A magnetic shield cover 14 surrounds the deflection yoke 8 along its outer shape.

Here, FIGS. 3 and 4 show cathode ray tubes with and without a magnetic shield cover 14 attached to the deflection yoke 8. According to this, in the case of FIG. 3 without the shield cover 14, the leakage magnetic field 15 extends far, whereas in this invention surrounded by the shield cover 14, the leakage magnetic field 15 is shielded as shown in FIG. This reduces the amount of leakage to the outside. As shown in FIG. 5, this situation shows that most of the leakage magnetic field 15 generated from the deflection yoke 8 is absorbed by the shield cover 14, and the amount radiated to the outside is weakened.

Figure 6 shows a canceling coil 1 on the inner surface of the magnetic shield cover 14.
6a, 16b is shown, and this canceling coil 15a
, 16b are horizontal deflection coils 9a, 9 as shown in FIG.
Similar to b, these are connected in parallel. With this configuration, as shown in FIG.
The leakage magnetic field 15 generated from the deflection yoke 8 is canceled by the canceling magnetic field 17 from the deflection yoke 8, and furthermore, since it is shielded by the magnetic shield cover 14, the leakage magnetic field 15 can be efficiently reduced.

In the embodiment, the magnetic shield cover 14 has a shape that follows the outer shape of the deflection yoke 8, but the shape and size are not limited. Also, a cancellation coil 16a.

The number, shape, size, number of turns, and position within the air shield cover 14 of the air shield cover 16b are not limited. Further, the material for the magnetic shield cover 14 may be any material as long as it can shield leakage magnetic fields.

〔Effect of the invention〕

As explained above, according to the present invention, the deflection yoke attached to the cathode ray tube is surrounded by a magnetic shield cover, so that leakage magnetic field from the deflection yoke is shielded and radiation to the outside is effectively reduced. I can do it. This can reduce the magnetic influence of leakage magnetic fields on devices near the deflection yoke, or on people and animals.

[Brief explanation of drawings]

FIG. 1 is an external view of a cathode ray tube as an image display device according to an embodiment of the present invention, FIG. 2 is a perspective view of a deflection yoke surrounded by a magnetic shield cover, and FIGS. 3 and 4 are views of a magnetic shield cover. External views of two cathode ray tubes comparing leakage magnetic fields with and without the presence of the leakage magnetic field. Fig. 5 is an explanatory diagram of the shielding effect of the magnetic shield cover on leakage magnetic fields. Fig. 6 is an external view of a shield cover showing another embodiment according to the present invention. , FIG. 7 is a connection diagram between the cancellation coil and the deflection coil, FIG. 8 is an explanatory diagram of the canceling effect of the leakage magnetic field in another embodiment, FIG. 9 is an external view of a conventional cathode ray tube, and FIG. Perspective view of deflection yoke, first
FIG. 1 is a schematic diagram of the winding pattern of the horizontal deflection coil, and FIG. 12 is a diagram of the magnetic fields generated by the horizontal and vertical deflection coils. ■...Cathode ray tube, 3...Panel, 6...Electron gun,
8... Deflection yoke, 9a, 9b... Horizontal deflection coil,
10a, 10b... Vertical deflection coil, 11... Core, 14... Magnetic shield cover 16a, 16b...
・Cancellation coil. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] In an image display device that includes an electron gun and a phosphor screen inside a cathode ray tube, and a deflection yoke consisting of a deflection coil and a core outside, a magnetic field that surrounds the deflection yoke from the outside and blocks magnetic fields leaking from the deflection yoke is used. An image display device characterized by being provided with a shield cover.