JPH056743A - Image display device - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain an image display device that has both the electric shock prevention function of the terminal board and the function of reducing the leakage magnetic field generated from the horizontal change coil. [Structure] Electric shock prevention protective covers 5a, 5b for covering the terminal boards 2a, 2b of the deflection yoke 1 are provided, and a cancel coil 6a for reducing a leakage magnetic field from a horizontal deflection coil is provided in the electric shock prevention protective covers 5a, 5b. 6b is integrally mounted to form a compact structure. [Effect] Prevention of electric shock and reduction of the leakage magnetic field from the horizontal deflection coil can be achieved at the same time, and the deflection yoke itself can be made compact to reduce the manufacturing cost.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device capable of reducing a leakage magnetic field from a cathode ray deflecting device.

[0002]

2. Description of the Related Art FIG. 4 is a schematic diagram showing the structure of a conventional image display device.

In the figure, 13 is a cathode ray tube,
Reference numeral 14 denotes a panel which is an image display portion of the cathode ray tube 13, and a phosphor film 15 is formed on the inner surface of the panel 14. Further, 1 is a deflection yoke, which is an electron gun 17
The electron beam 16 emitted from the electron beam 16 is deflected vertically and horizontally. Reference numeral 10 is a connector for receiving a deflection current supplied from an external device (not shown) for operating the cathode ray tube 13, and supplies the deflection current to the terminal boards 2a, 2b on the side of the deflection yoke 1 via the lead wire 7. Is configured to.

The connector 10 includes the deflection yoke 1
Terminals 8a and 8b for receiving the deflection current supplied to the horizontal deflection coils 3a and 3b, and the vertical deflection coils 4a and 4
terminals 9a, 9b for receiving the deflection current supplied to b
And are provided. Further, 6a and 6b are canceling coils for reducing the leakage magnetic field from the horizontal deflection coil, which are provided above and below the deflection yoke 1, respectively.
It is arranged.

FIG. 5 is a circuit diagram of a horizontal deflection coil and a cancel coil of a conventional deflection yoke. In FIG. 5, the horizontal deflection coils 3a and 3b of the deflection yoke 1 and the cancel coils 6a and 6b are connected in series. It is connected. In addition, 8a and 8b are horizontal connector terminals.

Next, the operation of the above configuration will be described with reference to FIG. To display an image on the panel 14 side, the electron gun 1
This is realized by deflecting the electron beam 16 emitted from the electron beam No. 7 by an appropriate deflection magnetic field generated from the deflection yoke 1 and accurately projecting the deflected electron beam 16 onto a predetermined position of the phosphor film 15 on the inner surface of the panel 14. it can.

Here, the deflection yoke 1 has horizontal deflection coils 3a, 3 for horizontally deflecting an electron beam.
b and a vertical deflection coil 4a for vertically deflecting,
4b, and the receiver terminals 8a, 8 of the connector 10
The deflection current is supplied to the horizontal deflection coils 3a and 3b from the terminal b via the terminal board 2a, and the deflection current is supplied from the receiver terminals 9a and 9b via the terminal board 2b to the vertical deflection coils 3a and 3b.
Each of them operates as supplied.

In the above description, the deflection current flowing through the horizontal deflection coil and the vertical deflection coil is usually a saw-tooth type alternating current, and the deflection current flowing through the vertical deflection coil has a frequency as low as several tens Hz, which is relatively low. In comparison with this, the frequency of the deflection current flowing to the horizontal deflection coil side is very large.

In recent years, in cathode ray tubes, the resolution of images has been improved,
There is a great demand for high-density display, and the frequency of the horizontal deflection current is increased as one means of this high-density display. In the current color TV system, this frequency is 15.75 KHz, but in the cathode ray used for a high-resolution display or the like, high deflection currents of 31 KHz and 64 KHz are used.

Here, the deflection magnetic field generated by this high-frequency current may be generated only for deflecting the electron beam inside the deflection yoke, but actually, it is also generated outside as a leakage magnetic field. This leakage magnetic field not only adversely affects peripheral devices such as electronic devices and electric appliances existing in the vicinity, but also has an adverse effect on human bodies and animals.

As a countermeasure against this, for example, the above-mentioned leakage magnetic field is reduced by the cancel coils 6a and 6b shown in FIG.

The cancel coils 6a and 6b are specifically the horizontal deflection coils 3a and 3b, as shown in FIG.
Is connected in series with the horizontal deflection coil, is wound in a direction to cancel the leakage magnetic field in synchronization with the horizontal deflection coil, and is arranged in pairs in the vertical direction of the deflection yoke 1 as shown in FIG.

On the other hand, since the deflection current is supplied to the deflection yoke 1, the current is also applied to the terminal portions on the surfaces of the terminal substrates 2a and 2b shown in FIG. 4, and the operating device for the cathode ray tube is repaired. There is a risk of electric shock due to contact with this during inspection.

As a measure for preventing this electric shock, for example, FIG.
As shown in FIG. 2, there is a terminal board 2a, 2b arranged at the upper and lower positions of the deflection yoke 1, and electric shock preventive protection covers 5a, 5b for covering the terminal board 2a, 2b are attached from above.

However, as described above, the terminal board 2
When attaching the electric shock preventive protective covers 5a, 5b to the a, 2b, the electric shock preventive protective covers 5a, 5b occupy a large space above and below the deflection yoke 1, and the cancel coils 6a, 6b shown in FIG. There is an inconvenience that it becomes difficult.

[0016]

As described above, in the conventional deflection yoke device in the cathode ray tube, when the cancel coil is attached and installed in order to reduce the leakage magnetic field from the horizontal deflection coil, the terminals of the deflection yoke are installed. It is physically difficult to attach the electric shock preventive cover for preventing electric shock by the board, and conversely, if the electric shock preventive protective cover is to be attached and installed, it is difficult to install and install the cancel coil.

In short, it has been difficult to mount and install the cancel coil and mount and install the electric shock protection cover for preventing electric shock at the same time.

The present invention has been made in order to solve the above problems, and is an image display capable of simultaneously realizing a measure for reducing a leakage magnetic field from the deflection yoke and a measure for preventing electric shock by the terminal substrate of the deflection yoke. The purpose is to provide a device.

[0019]

In order to achieve the above object, according to the present invention, in an image display device, an electric shock preventive protection cover for covering a terminal substrate of a deflection yoke and a cancel coil installed in the electric shock preventive protection cover are provided. This cancellation coil is characterized in that it is connected in series with the horizontal deflection coil of the deflection yoke and is wound so as to cancel the leakage magnetic field generated from the horizontal deflection coil.

[0020]

According to the present invention, since the terminal board of the deflection yoke which causes an electric shock is covered by the electric shock preventive protection cover, there is no danger of electric shock due to contact with the terminal board, and at the same time, the electric shock preventive method is provided. Since the cancel coil is provided in the protective cover, the magnetic field generated from the cancel coil cancels the leakage magnetic field generated from the horizontal deflection coil, and as a result, the leakage magnetic field can be reduced.

[0021]

EXAMPLE 1 An example of the present invention will be described below. 1 is a schematic view of a deflection yoke portion of an image display apparatus according to an embodiment of the present invention as seen from the side, FIG. 2 is a schematic view of FIG. 1 as seen from above, and FIG. 3 is a horizontal deflection coil and a cancel coil of the deflection yoke. FIG. The same or corresponding parts as those in the drawing showing the conventional example are designated by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 1, reference numerals 5a and 5b denote protective covers for preventing electric shock, which are attached to the terminal boards 2a and 2b located above and below the deflection yoke 1 so as to cover these terminal boards from above. Further, 6a and 6b are canceling coils for canceling the horizontal leakage magnetic field generated from the deflection yoke 1, which are arranged inside the electric shock preventing and protecting covers 5a and 5b in a loop shape.

Here, the cancel coils 6a, 6 described above are used.
As shown in FIG. 3, b is connected in series with the horizontal deflection coils 3a and 3b of the deflection yoke.
It is assumed that the same alternating current flows as the temporal change of the alternating current flowing through a and 3b.

Further, in FIG. 3, when the electric shock preventive protection covers 5a and 5b are not attached, the terminal 11a is provided.
And 11b and the terminals 12a and 12b are short-circuited, and if the electric shock protection covers 5a and 5b are attached,
The terminals 11a and 11b and the terminals 12a and 12b are opened, and the horizontal deflection current is applied to the cancel coils 6a and 6b.

According to the above-described embodiment, as shown in FIG. 1, cancel coils 6a and 6b for canceling the leakage magnetic field from the horizontal deflection coils 3a and 3b are arranged inside the electric shock preventive protection covers 5a and 5b. Since it is mounted, it is possible to simultaneously perform the two functions of preventing the electric shock to the terminal board and reducing the leakage magnetic field. Therefore, as in the conventional example shown in FIG. 4 and FIG.
It is not necessary to separately provide the cancel coils 6a and 6b and the cancel coils 6a and 6b, and the number of parts and the number of manufacturing steps can be reduced.

Further, since the electric shock prevention protective cover and the cancel coil are integrated, the deflection yoke itself becomes very compact.

By the way, when the electric shock preventive cover is not attached, as shown in FIG.
By short-circuiting b and 12a, 12b, a normal deflection current is applied to the horizontal deflection coils 3a, 3b, and a deflection magnetic field is generated. On the other hand, as in the above embodiment, only when the electric shock preventive protection covers 5a and 5b are attached, the terminal 11
a, 11b and 12a, 12b are opened, the horizontal deflection current is supplied to the leakage magnetic field canceling coils 6a, 6b, and a magnetic field is generated in a direction of canceling the horizontal deflection magnetic field in synchronization with the horizontal deflection current to reduce the leakage magnetic field. It acts.

In the above embodiment, as shown in FIG. 1, the cancel coils 6a and 6b are arranged in the upper and lower pairs of the deflection yoke 1 by way of example, but as another embodiment,
For example, the cancel coil may be arranged only on either the upper side or the lower side of the deflection yoke.

The shape and size of the cancel coil, the electric shock protection cover, and the setting angle of the cancel coil are not particularly limited, and can be appropriately selected in consideration of various conditions.

[0030]

As described above, according to the image display device of the present invention, since the electric shock preventive protection cover of the terminal board and the leakage magnetic field canceling coil are integrated, both functions can be exhibited at the same time. In addition, the deflection yoke itself can be designed compactly, and it is possible to provide it at low cost.

[Brief description of drawings]

FIG. 1 is a schematic side view of a deflection yoke portion in an image display device according to an embodiment of the present invention.

FIG. 2 is a schematic view of FIG. 1 as viewed from above.

FIG. 3 is a circuit diagram of a horizontal deflection coil and a cancellation coil of a deflection yoke.

FIG. 4 is a schematic diagram showing a configuration of a conventional cathode ray tube.

FIG. 5 is a circuit diagram of a horizontal deflection coil and a cancel coil of a conventional deflection yoke.

FIG. 6 is a diagram illustrating a state in which an electric shock protection cover is attached to a conventional deflection yoke device.

[Explanation of symbols]

 1 Deflection yoke 2a, 2b Terminal board 3a, 3b Horizontal deflection coil 5a, 5b Electric shock prevention protective cover 6a, 6b Cancel coil

Claims (1)

Claim: What is claimed is: 1. A cathode ray tube having at least one electron gun, a phosphor screen, and a deflection yoke on the inside thereof, and a protection cover for protecting the terminal board of the deflection yoke, and a protection against this electric shock. A cancel coil incorporated in the protective cover is provided, the cancel coil being connected in series with the horizontal deflection coil of the deflection yoke, and being wound so as to cancel a leakage magnetic field generated from the horizontal deflection coil. Characteristic image display device.