JPH09230816A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the configuration simple and to reduce largely leakage magnetic field without having an effect on other characteristics. SOLUTION: In a display device provided with a cathode-ray tube 200 which is scanned by an electron beam from an electron gun 11 by action of a deflection yoke 7, an annular space is formed in a virtual flat surface in the vertical direction to the irradiating direction of the electron beam by a lead wire 32 making to flow a current in a horizontal deflection coil 7A of the deflection yoke. Magnetic force of the reverse direction leaked from the horizontal deflection coil 7A of the deflection yoke 7 is reduced by magnetic force developed through this annular space.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, and more particularly to a display device having a cathode ray tube in which an electron beam from an electron gun is scanned by the action of a deflection yoke.

[0002]

2. Description of the Related Art It is known that a display device having a so-called cathode ray tube generates a leakage magnetic field around it.

Attempts to reduce this leakage magnetic field have been strongly demanded from ergonomics detection. For example, in the Swedish MPR-2 regulation, the magnetic field at a position 50 cm from the center of the screen is 25 n.
It stipulates that it must be kept below T.

For this reason, attempts have been made to improve the flyback transformer (FBT), attach a shield plate, or downsize the deflection yoke.

[0005]

However, the improvement of the flyback transformer and the attachment of the shield plate make the structure complicated (which leads to an increase in cost), and
It has been pointed out that miniaturization of the deflection yoke will result in deterioration of convergence and distortion characteristics.

The present invention has been made under such circumstances, and an object thereof is to achieve a large reduction of a leakage magnetic field with a simple structure and without affecting other characteristics. It is to provide a display device that can be used.

[0007]

In order to achieve such an object, the present invention basically provides a display device having a cathode ray tube in which an electron beam from an electron gun is scanned by the action of a deflection yoke. , A ring-shaped space is formed by a lead wire for flowing a current through a horizontal deflection coil of the deflection yoke in a virtual plane whose irradiation direction of the electron beam is substantially vertical, and a magnetic force is formed through the ring-shaped space. The magnetic force in the opposite direction leaked from the horizontal deflection coil is reduced.

The display device constructed as described above is
Since the leakage magnetic field from the deflection yoke can be reduced by simply forming the annular space by the lead wire that causes the current to flow through the horizontal deflection coil, a very simple configuration is required.

Further, since the method of improving the parts in order to reduce the magnetic field itself is not adopted, the structure has no influence on other characteristics.

As a result, the structure is simple, and the leakage magnetic field can be greatly reduced without affecting other characteristics.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. FIG. 1 is a configuration diagram showing an embodiment of a display device according to the present invention, and is a side view partially showing a cross section.

The display device shown here is, for example, a personal computer or an EWS (engineer).
ing work station) and other information terminal color displays.

In FIG. 1, there is a chassis 100 which is an outer frame of the display device, and a cathode ray tube 200 is built in the chassis 100 with its display portion 200A exposed.

In the cathode ray tube 200, there is an electron gun assembly 11 which emits electrons as a beam. The electron gun assembly 11 has an integrated structure in which R (red), G (green), and B (blue) electron guns are arranged in the x direction in the drawing, and each electron beam 12 emits an electron beam 12. It is supposed to be irradiated.

Further, the fluorescent screen 4 faces the electron gun assembly 11.
Are arranged, and the phosphor screen 4 is provided with regions of respective pixels arranged in a matrix.

The area corresponding to one pixel of the phosphor screen 4 is irradiated with the electron beams 12 to generate R.
Phosphors that emit (red), G (green), and B (blue) are arranged adjacent to each other. One pixel configured as described above is irradiated to each corresponding phosphor by passing each electron beam 12 from each electron gun of the electron gun structure 11 through the same electron transmission hole of the shadow mask 13. As a result, the respective phosphors are colored.

The electron gun structure 11 and the fluorescent screen 4 are enclosed by a vacuum envelope 20 made of glass, and the fluorescent screen 4 is contained in the panel portion 1 of the envelope 20.
It is arranged so as to be attached to the inner wall surface of the part called. Here, the panel unit 1 serves as the display unit 200A of the cathode ray tube 200, and an observer can recognize the color development of each pixel of the phosphor screen 4 through the panel unit 1.

The portion of the envelope 20 that encloses the electron gun assembly 11 is called a neck portion 3, and the portion between the neck portion 3 and the panel portion 1 is called a funnel portion 2.

A deflection yoke 7 is arranged on the outer periphery of the funnel portion 2 of the envelope 20, and the deflection yoke 7 is
It is composed of a horizontal deflection coil 7A and a vertical deflection coil 7B.

The scanning of the electron beam 12 is performed by the action of the deflection yoke 7, and the horizontal scanning (in the x direction in the drawing) is performed by the horizontal deflection coil 7A.
The vertical deflection coil 7B is responsible for vertical scanning (y direction in the drawing). As a result, the electron beam 12 is sequentially irradiated to each pixel on the phosphor screen 4.

The deflection yoke 7 is connected with a lead wire for passing a current from the electronic circuit mounting board 30 arranged at the bottom of the chassis 100 to the deflection yoke 7. An annular space 33 is formed by a pair of lead wires 32 that pass a current through the coil 7A.

An annular space 33 formed by the lead wire 32 is formed below the neck portion 3 of the cathode ray tube 200 and in the xy plane in the figure, that is, the electron beam 1
It is formed so as to be included in an imaginary plane whose irradiation direction is substantially vertical.

Here, the arrangement relationship of the lead wires 33 of each of the pair of lead wires 32 forming the annular space 33 is specified. From this, the details of the arrangement relationship will be described. Will be described with reference to FIG.

In the figure, first, consider the case where the current flowing through the horizontal deflection coil 7A via the lead wire 32 is in the direction shown in the figure (counterclockwise with respect to the + y direction). In this case, the magnetic field M generated between the pair of horizontal deflection coils 7A is in the lower (-y) direction in the figure, and the electron beam emitted from the electron gun 11 in the z direction is swung in the x direction in the figure to cause fluorescence. The body surface 4 is scanned in the x direction in the figure.

The respective lead wires 32 are arranged in the annular space 33 formed by the pair of lead wires 32 so that current flows in the direction shown in the drawing (counterclockwise with respect to the + z direction). It has become so.

In this case, a magnetic field is generated in the annular space 33 formed by the lead wire 33 in the arrow A (-z direction) in the figure, and this magnetic field is generated by the pair of horizontal deflection coils 7A.
The magnetic field m generated in the opposite direction (+ z direction) of the leakage magnetic field of the magnetic field M generated during the period will be reduced.

In this case, the direction of the current flowing in the horizontal deflection coil 7A is not always a constant direction but sequentially flows in the opposite direction over time. However, even when the current flows in the opposite direction, the leakage magnetic field is generated. Since the direction (-z direction in the drawing) is different and the direction of the magnetic field in the annular space 33 (+ z direction) is also different, the same effect as described above can be obtained.

As described above, according to the display device shown in the first embodiment, the leakage magnetic field from the horizontal deflection coil 7A is generated by simply forming the annular space 33 by the lead wire 32 for supplying the current to the horizontal deflection coil 7A. Since it can be reduced, a very simple structure will be sufficient.

Further, since the method of improving the parts in order to reduce the magnetic field itself is not adopted, the structure has no influence on other characteristics.

As a result, the structure is simple, and the leakage magnetic field can be greatly reduced without affecting other characteristics.

Here, in the above-mentioned structure, when the lead wire 32 forms a circle having a diameter of about 50 mm, a leakage magnetic field of 1 to 3 nT can be reduced, and the leakage magnetic field can be reduced to about 3.
It was found that a leakage magnetic field reduction of 7 to 12 nT could be achieved when a circle with a diameter of 00 mm was made.

In the above-mentioned embodiment, the annular space 33 is formed by the pair of lead wires 32 for supplying the current to the horizontal deflection coil 7A, but the present invention is not limited to this, and the pair of lead wires is not limited thereto. It goes without saying that the same effect can be obtained by forming the annular space 33 by one of the lead wires 32 of 32.

Example 2. In this embodiment, the lead wire 32 is
By providing a plurality of annular spaces 33 formed at different locations, the leakage magnetic field is further reduced.

That is, in the case of the first embodiment, the cathode ray tube 2
The annular space 33 is provided on the lower side of the neck portion 3 of No. 00, but as shown in FIG.
Is provided.

In this case, since the lower leakage magnetic field m and the upper leakage magnetic field m ′ with respect to the neck portion 3 have different directions, the annular space 34 provided above the neck portion 3 is surrounded. It is necessary to arrange the lead wire 32 so that the direction of the current flowing through the lead wire 32 is opposite to the direction of the current flowing through the lead wire 32 surrounding the annular space 33 provided below the neck portion 3.

With this configuration, it is possible to further reduce the leakage magnetic field.

In Embodiment 1 described above, one annular space 33 formed by the lead wire 32 is provided below the neck portion 3 of the cathode ray tube 200, but the present invention is not limited to this, and the same. Needless to say, a plurality of pieces may be provided below the neck portion 3. Further, it is needless to say that the number is not limited to the lower side of the neck portion 3 of the cathode ray tube 200, and a plurality of them may be provided only on the upper side.

In the second embodiment described above, the cathode ray tube 2
The annular spaces 33 and 34 formed by the lead wires 32 are provided on the upper and lower sides of the neck portion 3 of No. 00, respectively, but the invention is not limited to this and a plurality of them may be provided. Needless to say.

Further, in the above-mentioned embodiment, only the reduction of the leakage magnetic field by the horizontal deflection coil has been described. However, even in the reduction of the leakage magnetic field by the vertical deflection coil, a lead wire for supplying a current to the vertical deflection coil is used. It goes without saying that the configuration described above can be applied.

It is needless to say that each annular space formed by the lead wire 32 is not limited to a circular shape, and may be another shape such as an ellipse or a rectangle. The point is that the same effect can be obtained if a space closed by the lead wire 32 is formed.

[0041]

As is apparent from the above description,
According to the display device of the present invention, the configuration is simple, and the leakage magnetic field can be significantly reduced without affecting other characteristics.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a display device according to the present invention.

FIG. 2 is an explanatory diagram showing a positional relationship between a horizontal deflection coil and a lead wire of the display device according to the present invention.

FIG. 3 is a configuration diagram showing another embodiment of the display device according to the present invention.

[Explanation of symbols]

7A ... horizontal deflection coil, 12 ... electron beam, 32 ...
… Lead wire, 33,34 …… annular space.

Claims (2)

[Claims] 1. A display device including a cathode ray tube in which an electron beam from an electron gun is scanned by the action of a deflection yoke, wherein a deflection plane of the deflection yoke is provided in an imaginary plane whose irradiation direction of the electron beam is substantially vertical. An annular space is formed by a lead wire for supplying a current to the horizontal deflection coil, and the magnetic force formed through the annular space reduces the magnetic force in the opposite direction leaked from the horizontal deflection coil of the deflection yoke. Display device. 2. The display device according to claim 1, wherein a plurality of annular spaces formed by the lead wires are provided at different locations.