JP2000353480A - Deflection yoke, cathode-ray tube device and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the leakage magnetic field from the magnetic substance core of a nearly rectangular deflection yoke. SOLUTION: This deflection yoke is provided with a horizontal deflection coil, a vertical deflection coil and a nearly rectangular magnetic substance core 4 provided on the outside of the deflection coils. Notches 11-14 of a nearly semielliptical shape, a nearly rectangular shape, a nearly triangular shape, a nearly semirhombic shape or a combined shape of them are provided on the short side of the fluorescent screen side end section of the nearly rectangular magnetic substance core 4 or on the long side of the nearly rectangular magnetic substance core 4. The height of the notch section provided on the short side of the nearly rectangular magnetic substance core 4 is set to 1.5 mm or above, and the height of the notch section provided on the long side is set to 1.2 mm or above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deflection yoke for a cathode ray tube and a display device using the deflection yoke, and more particularly to a deflection yoke having a substantially rectangular deflection yoke with a reduced core leakage magnetic field. Involved in York.

[0002]

2. Description of the Related Art A conventional deflection yoke is disclosed in JP-A-8-7781.
As disclosed in Japanese Unexamined Patent Application Publication No. H11-107, a technique for reducing the driving power of the deflection yoke by using a deflection yoke whose core shape is changed from a round shape to a substantially rectangular shape is disclosed. FIG. 11 shows an example of a conventional rectangular core. However, in recent years, the drive current of the deflection yoke has increased with the wide-angle deflection of the display device, and there has been a problem that the leakage magnetic field from the deflection yoke increases.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the conventional problems and to provide a cathode ray tube device and a display device in which a leakage magnetic field from a deflection yoke using a rectangular core is reduced. To provide.

[0004]

In a deflection yoke having a horizontal deflection coil, a vertical deflection coil, and a substantially rectangular magnetic core, a notch is provided at an end of the rectangular core on the fluorescent screen side. It is a deflection yoke.

According to the present invention, there is provided a cathode ray tube apparatus including a deflection yoke including a horizontal deflection coil, a vertical deflection coil, and a substantially rectangular magnetic core. A cathode ray tube device.

According to the present invention, there is provided a display device comprising a deflection circuit for driving a deflection yoke, a video circuit for driving a cathode ray tube, and the like, wherein the deflection yoke is the above-described deflection yoke.

[0007]

Embodiments of the present invention will be described below.

An embodiment of a deflection yoke, a cathode ray tube and a display device according to the present invention will be described with reference to FIGS. FIG. 1 is an explanatory side view of the cathode ray tube device used in the first embodiment. 2, 3, and 4 are a perspective view, a front view, and a top view, respectively, of the high-permeability magnetic core used in the first embodiment. FIG. 5 is an explanatory diagram showing the relationship between the height Hh of the notch provided on the long side of the rectangular core according to the first embodiment and the leakage magnetic field caused by the horizontal deflection magnetic field. FIG. 6 is an explanatory front view of a magnetic core having a high magnetic permeability used in the first embodiment. FIG. 7 is an explanatory diagram showing the relationship between the height Hv of the notch provided on the short side of the rectangular core according to the first embodiment and the leakage magnetic field caused by the vertical deflection magnetic field. 8 and 9 show Example 2,
FIG. 14 is an explanatory top view showing a cutout shape of a core used in a third embodiment. FIG. 10 is a block diagram illustrating a configuration of a display device using the deflection yoke according to the fourth embodiment.

Embodiment 1 will be described. As shown in FIG. 1, the deflection yoke 1 of this embodiment is mounted on a color cathode ray tube device, and includes a horizontal deflection coil 2, a vertical deflection coil 3, and a magnetic core 4 having a high magnetic permeability (hereinafter abbreviated as a core). , A separator 5. In FIG. 1, a part of the separator 5 of the deflection yoke 1 is cut away to show the inside thereof. The deflection yoke 1 is used by being attached to a portion extending from the funnel portion 9 to the neck portion 7 of the cathode ray tube 6. A plurality of electron beams (not shown) emitted from the electron gun 8 are supplied to the deflection yoke 1
Thus, a color fluorescent screen (not shown) applied to the inner surface of the panel 10 is electromagnetically deflected vertically and horizontally to emit light, thereby reproducing a color image.

An example of a more detailed structure of the core 4 used in the deflection yoke of the present embodiment will be described with reference to a perspective view of the core of FIG. 2, a front view of the core of FIG. 3, and a plan view of the core of FIG.
The core 4 used in this embodiment is made of a ferrite material having a high magnetic permeability, and as shown in the front view of FIG. 3, the shape of the core at the end on the phosphor screen side is substantially rectangular. As shown in FIG. 2, the core 4 is divided into a pair of cores 4 a and 4 b on the split surface 9 after sintering the ferrite material. After the split cores 4a and 4b are assembled in the deflection yoke 1,
And is fixed by the clamp fitting 15. The core 4 (4a, 4b) has a notch 1 above the phosphor screen side end.
1, a notch 12 is provided on the lower side, a notch 13 is provided on the right side, and a notch 14 is provided on the left side.

The arrows in FIG. 3 schematically show the lines of magnetic force of the horizontal deflection magnetic field 16 generated by the horizontal deflection coil 2 (not shown). The magnetic field 16 is a line of magnetic force directed in the y (perpendicular) direction, and most of the line of magnetic force is absorbed by the core 4 (4a, 4b) made of a ferrite material having a high magnetic permeability (a relative magnetic permeability of about several hundreds). The magnetic force lines 17 pass through. On the other hand, as shown in FIGS. 3 and 1, a part of the magnetic field lines 17 leaks from the upper surface of the core 4 to the outside, and becomes a leakage magnetic field 18 returning to the lower surface of the core. The cutouts 11 and 12 do not have a high permeability core material (having a relative permeability of several hundreds) and have the permeability of air (relative permeability is about 1), so that the magnetic material is inversely proportional to the relative permeability. Since the resistance increases at the notch, the leakage magnetic field 19 at the notch is much smaller than the leakage magnetic field 18 coming out of the surface of the core 4. Therefore, most of the leakage magnetic field
Most of the magnetic field 18 radiated from the core material near the end surfaces of the notches 11 and 12 into the surrounding space. Therefore, the leakage magnetic field 18 from the core 4 is, as shown in FIG.
The panel 10 is separated from the panel 10 by the notch. As a result, as shown in FIG. 1, it is possible to reduce the leakage magnetic field measured by the detector 50 installed at a measurement point separated from the panel 10 by a certain distance (for example, 50 cm or 30 cm).

FIG. 5 shows the height Hh (shown in FIG. 4) of the notches 11 and 12 of the core 4 and the leakage magnetic field (VLMF: Very Low frequency Magnetic Field,
This is a result of measuring a leakage magnetic field in a frequency range of 2 kHz to 400 kHz, and confirms that the VLMF can be reduced by 10% or more by setting the notch height Hh to 1.2 mm or more.

Similarly, the leakage magnetic field from the vertical deflection coil 3 will be described with reference to FIGS. 6, a vertical deflection magnetic field 20 generated in the x (horizontal) direction generated by the vertical deflection coil 3 (not shown) is schematically indicated by an arrow.
The vertical deflection magnetic field 20 is a line of magnetic force substantially orthogonal to the horizontal deflection magnetic field 16. The magnetic field 22 leaked from the right surface of the core 4 to the outside returns to the left surface of the core 4 due to the vertical deflection magnetic field, and the leakage magnetic field 22 (ELMF: Extr
emery Low frequency Magnetic Field, 5H frequency range
z to a leakage magnetic field of 2 kHz). Further, the fact that the magnetic field 23 leaking from the left and right cutouts 13 and 14 is much smaller than the leaked magnetic field 22 is the same as the reason explained for the leaked magnetic field of the horizontal deflection magnetic field, and the explanation is omitted.

FIG. 7 shows the results of measuring the height Hv of the cutout 13 on the right side of the core 4 and the height Hv of the cutout 14 on the left side and the ELMF caused by the vertical deflection magnetic field.
Is set to 1.5 mm or more, so that ELMF can be reduced by 10%.
It has been confirmed that the above can be reduced.

Embodiments 2 and 3 will be described with reference to FIGS. FIG. 8 is an explanatory top view of the core 4 having a rectangular notch used in the second embodiment. FIG. 9 is an explanatory top view of the core 4 having a triangular cutout used in the third embodiment. The operation of the notch is the same as that of the first embodiment, and the description is omitted. Further, the shape of the notch is not limited to the above-described shape, and it goes without saying that the notch may have another shape.

Although the core 4 used in the first, second and third embodiments has been described using a core composed of a pair of cores 4a and 4b divided by a split surface 9, the core is not divided. It is needless to say that the leakage magnetic field can be similarly reduced by providing the notch in the core. In the above embodiment, the cutouts are provided on both the long side and the short side of the core 4.
By providing a cutout in either one as required, either VLME or ELMF can be reduced.

Embodiment 4 will be described with reference to FIG. FIG.
0 shows a display device in which a cathode ray tube provided with a deflection yoke of this embodiment and its peripheral circuits are shown by blocks. The display device of the present embodiment has a video signal input terminal 44,
It comprises an input terminal 45 for a horizontal synchronizing signal, an input terminal 46 for a vertical synchronizing signal, a video circuit 40, a horizontal deflection circuit 41, a vertical deflection circuit 42, a high voltage circuit 43, and the like, and a portion corresponding to the cathode ray tube device shown in FIG. Are given the same reference numerals. The horizontal synchronizing signal from the input terminal 45 is also supplied to the high voltage circuit 43, and generates a DC high voltage of several tens kV. The high voltage is applied to an anode terminal (not shown) of the cathode ray tube 6 and an electron beam (not shown) emitted from the electron gun 8 is applied to the panel 10.
Accelerate to the phosphor screen applied to the inner surface of.

After the video signal from the input terminal 44 is processed by the video circuit, it is supplied to, for example, the cathode of a cathode ray tube, and the electron beam amount is modulated according to the content of the video signal. The horizontal synchronization signal from the input terminal 45 is supplied to the horizontal deflection circuit 4
1, a horizontal deflection current IH is generated, and the horizontal deflection current IH is supplied to the horizontal deflection coil 2 of the deflection yoke 1 to generate a horizontal deflection magnetic field.

On the other hand, a vertical synchronizing signal from an input terminal 46 is supplied to a vertical deflection circuit 42 to generate a vertical deflection current IV, which is supplied to a vertical coil 3 of the deflection yoke 1 to generate a vertical deflection magnetic field. By deflecting the electron beam from the electron gun 8 vertically and horizontally by these horizontal and vertical deflection magnetic fields, an image can be reproduced on a fluorescent screen (not shown) on the inner surface of the panel 10. In this way, by applying the deflection yoke 1 of the present invention, the cathode ray tube 6 is driven, and a display device with a small leakage magnetic field can be obtained.

[0020]

As described above, according to the deflection yoke of the present invention, a notch is provided at the end of the substantially rectangular magnetic core on the phosphor screen side, thereby providing a display device with a small leakage magnetic field. be able to.

[Brief description of the drawings]

FIG. 1 is an explanatory side view showing a cathode ray tube device used in a first embodiment.

FIG. 2 is a perspective view showing a rectangular core of the deflection yoke used in the first embodiment.

FIG. 3 is a front view showing a rectangular core of the deflection yoke used in the first embodiment.

FIG. 4 is a top view showing a rectangular core of the deflection yoke used in the first embodiment.

FIG. 5 is a diagram showing the core notch height and VLM used in the first embodiment.
FIG. 4 is a characteristic diagram showing a relationship of F.

FIG. 6 is an explanatory diagram showing a rectangular core of the deflection yoke used in the first embodiment.

FIG. 7 shows the height of a core notch and ELM used in Example 1.
FIG. 4 is a characteristic diagram showing a relationship of F.

FIG. 8 is a top view showing a rectangular core of the deflection yoke used in the second embodiment.

FIG. 9 is a top view showing a rectangular core of the deflection yoke used in the third embodiment.

FIG. 10 is a block diagram illustrating a configuration of a display device using a deflection yoke according to a fourth embodiment.

FIGS. 11A and 11B are a front view and a top view showing a substantially rectangular core of a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Deflection yoke, 2 ... Horizontal deflection coil, 3 ... Vertical deflection coil, 4, 4a, 4a ... Rectangular magnetic core of high magnetic permeability,
5 separator, 6 cathode ray tube, 7 neck, 8 electron gun, 9 funnel, 10 panel, 15 clamp, 16 horizontal deflection magnetic field, 18 leakage magnetic field, 19
Leakage magnetic field, 20 ... Vertical deflection magnetic field, 22 ... Leakage magnetic field, 23
... Leakage magnetic field, 40 ... Video circuit, 41 ... Horizontal deflection circuit,
42 vertical deflection circuit, 43 high voltage circuit, 44 video input terminal, 45 horizontal synchronization signal input terminal, 46 vertical synchronization signal input terminal, 50 leakage magnetic field measuring device.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Souichi Sakurai 292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture Inside the Multimedia Systems Development Division of Hitachi, Ltd. (72) Inventor Koji Fukuma Yoshida, Totsuka-ku, Yokohama-shi, Kanagawa No. 292, Hitachi, Ltd. Multimedia System Development Division, Hitachi, Ltd. (72) Inventor Takanori Ishikawa 1 Kitano, Majo, Mizusawa-shi, Iwate Prefecture Inside Hitachi Media Electronics Co., Ltd. Address F-term in Hitachi, Ltd. Electronic Device Division (reference) 5C042 FG08 FG35

Claims (7)

[Claims] 1. A deflection yoke having a horizontal deflection coil, a vertical deflection coil, and a substantially rectangular magnetic core provided outside the deflection coil, the core being cut at an end on the fluorescent screen side of the core. A deflection yoke having a notch. 2. The deflection yoke according to claim 1, wherein the notch is formed on a short side of a phosphor screen end of the substantially rectangular core or on a long side of a phosphor screen end of the substantially rectangular core. A deflection yoke, which is provided. 3. The deflection yoke according to claim 2, wherein the height Hv of the notch provided on the short side of the rectangular core is 1.
A deflection yoke having a length of 5 mm or more. 4. The deflection yoke according to claim 2, wherein the height Hh of the notch provided on the long side of the rectangular core is 1.
A deflection yoke having a length of 2 mm or more. 5. The deflection yoke according to claim 1, wherein the notch formed at the end of the substantially rectangular core on the phosphor screen side has a substantially semi-elliptical shape or a substantially rectangular shape. A deflection yoke having a substantially triangular shape, a substantially semi- rhombic shape, or a combination of the above shapes. 6. A cathode ray tube device comprising the deflection yoke according to claim 1. 7. The display device according to claim 1, wherein the display device comprises a deflection yoke, a cathode ray tube device, a deflection circuit for driving the deflection yoke, a video circuit for driving the cathode ray tube, and the like. A display device comprising a yoke.