JPH07302557A - Deflection yoke - Google Patents

Abstract

PURPOSE:To stably and easily correct vertical raster pin cushion strain caused when a cathode ray tube is enlarged and widened and a screen surface is flattened. CONSTITUTION:A deflection yoke has an induction sub-coil 5 arranged outside of a vertical deflection coil 2 and a magnetic flux generating sub-coil 7 which is arranged in an opening end part on the screen side connected to the induction sub-coil 5 through a lead wire 6 and is wound round a magnetic substance iron core 8. An induced current induced to the induction sub-coil 5 by a leakage magnetic flux of a vertical deflecting magnetic flux generated in the vertical deflection coil 2, is supplied to the magnetic flux generating sub-coil 7, and a sub-deflecting magnetic field is generated in the magnetic flux generating sub-coil 7. Thereby, vertical raster pin cushion strain can be corrected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deflection yoke to be combined with a cathode ray tube used in a television receiver or the like.

[0002]

2. Description of the Related Art In recent years, cathode ray tubes (hereinafter referred to as CRTs)
Are rapidly increasing in size, widening, and flattening the screen surface, but along with this, deterioration of upper and lower raster pincushion distortion is likely to occur.

Conventionally, as a measure for preventing the deterioration of the upper and lower raster pincushion distortion, permanent magnets are arranged on the Y axis above and below the opening on the screen side of the deflection yoke, and the electron beam emitted from the electron gun is directed to the Y axis. It is pulled vertically to correct the upper and lower raster pincushion distortion. Therefore,
As the CRT becomes larger and wider and the screen surface becomes flatter, the upper and lower raster pincushion distortion is further aggravated, so that the volume of the permanent magnet arranged in the deflection yoke used to correct the distortion becomes larger. It was

At the same time, there is a demand for correction of upper and lower raster pincushion distortions because of the spread of high-definition and C
With the use in displays for ADAM and computer graphics, higher precision is required.

A conventional deflection yoke will be described below. As shown in FIG. 7, a horizontal deflection coil (not shown in the drawing) for horizontally deflecting the electron beam, an insulating frame 11 arranged so as to cover the horizontal deflection coil, and an outside of the insulating frame 11 are provided. A core 13 made of a magnetic material such as ferrite, around which a vertical deflection coil 12 for deflecting an electron beam in the vertical (Z-axis) direction is wound, is fixedly provided by a core stopper 14. On the Y-axis of the opening on the screen side to correct the vertical raster pincushion distortion (left and right in Fig. 7)
A permanent magnet 15 is provided in the.

As shown in FIG. 8, the permanent magnet 15 has a positive Y-axis.
When viewed from the screen side, the north pole is on the right and the south pole is on the left.
The screen is arranged in the negative direction of the Y-axis.
When viewed from the side, they are arranged so that the S pole is on the right and the N pole is on the left.
ing. The X axis in the figure indicates the vertical direction on the same plane as the Y axis.
Therefore, for example, as shown in FIG.
Is deflected in the positive direction of the Y-axis, the permanent magnet 15
Arrow emitted from φ _MArrow on the Y-axis due to the magnetic flux shown in
Since it receives the deflection force indicated by the mark F, it is a top and bottom raster pink
The distortion distortion was corrected.

A deflection yoke having an auxiliary coil for generating a magnetic field for canceling an unnecessary magnetic field of the horizontal deflection magnetic field, which is connected to the horizontal deflection coil outside the deflection yoke, is an invention (see, for example, Japanese Patent Laid-Open No. 3-283238). However, in this deflection yoke, there is no element that affects the upper and lower raster pincushion distortion.

[0008]

However, in the above-described conventional structure, the upper and lower raster pincushion distortion causes various manufacturing factors of the permanent magnet 15 (for example, the magnitude of magnetization, the magnitude of magnetization). Since it is greatly affected by the directionality and size), there is a problem that the correction is unstable and not easy.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a deflection yoke capable of stably and easily correcting the upper and lower raster pin cushions.

[0010]

To achieve this object, a deflection yoke according to the present invention comprises an induction subcoil disposed outside a vertical deflection coil and a screen side connected to the induction subcoil through a lead wire. In this structure, a magnetic flux generating sub coil wound around a magnetic iron core arranged at the opening end is provided.

[0011]

In this structure, since the leakage current of the vertical deflection magnetic flux generated in the vertical deflection coil supplies the induction current induced in the induction subcoil to the magnetic flux generation subcoil, the subdeflection magnetic field is generated in the magnetic flux generation subcoil. It occurs, and the upper and lower raster pincushion distortion is corrected.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIGS. 1 and 2, a horizontal deflection coil (not shown in the drawing) for horizontally deflecting the electron beam, and an insulating frame 1 arranged so as to cover the horizontal deflection coil, A core 3 made of a magnetic material such as ferrite, around which a vertical deflection coil 2 for deflecting an electron beam in a vertical (Z-axis) direction is wound, is fixed to a core stopper 4 and arranged outside an insulating frame 1.

The induction subcoil 5 is arranged outside the vertical deflection coil 2 so that a magnetic field leaking to the outside that does not contribute to the deflection of the electron beam of the vertical deflection coil 2 can pass therethrough, and the magnetic flux generating subcoil through the lead wire 6. Connected to 7. The magnetic flux generating sub-coil 7 is wound around a magnetic iron core 8, and the vertical position when the deflection yoke is mounted on the CRT (Y in the figure).
Are arranged in the axial direction). The X axis in the figure indicates the vertical direction on the same plane as the Y axis.

The operation of the deflection yoke having the above structure will be described below. As shown in FIG. 3, when a part of the leakage magnetic field indicated by the arrow φ _v of the vertical deflection coil 2 passes through the induction sub-coil 5, the induced electromotive force in the induction sub-coil 5 changes with time in the leakage magnetic field. Occurs in response to. The arrow I _c in the figure indicates the induced current, and the arrow A indicates the coil winding direction of the magnetic flux generating sub-coil 7.

At this time, the vertical deflection current I _v supplied to the vertical deflection coil 2 has a sawtooth wave as shown in FIG. 4A, and the vertical deflection magnetic field generated by the vertical deflection coil 2 also has a sawtooth wave. Becomes Therefore, the induced electromotive force (E = −dφ / dt) generated in the induction subcoil 5 has a substantially constant value as shown in FIG. 4B. The sign is inverted between the scanning period and the blanking period. Similarly, the induced current I _c also has a substantially constant value as shown in FIG.

The induced current I obtained as described above
_c is supplied to the magnetic flux generated secondary coil 7 as indicated by arrow I _c through the lead wires 6 as shown in FIG. The magnetic flux generating sub-coil 7 is wound around the magnetic iron core 10, and the arrow φ
Generates the sub-deflection magnetic field indicated by _c . As shown in FIG. 6A, when the electron beam 9 emitted from the electron gun by the above-mentioned sub-deflection magnetic field passes near the magnetic flux generating sub-coil 7, the electron beam 9 receives the upward deflection force indicated by the arrow F, As the deflection force decreases toward the left and right sides, as shown in FIG.
The upper and lower raster pincushion distortions are corrected as shown in (b).

The sub-deflection magnetic field is nI _c = nK
N (-dφ / dt) (where K is a constant, n is the number of turns of the magnetic flux generating subcoil 7, N is the number of turns of the induction subcoil 5, and
φ is magnetic flux, t is time). That is, the optimum value of the sub-deflection magnetic field can be selected depending on the number of turns of the magnetic flux generation subcoil 7 and the number of turns of the induction subcoil 5.

As described above, according to this embodiment, the induction subcoil 5 is provided outside the vertical deflection coil 2, and the induction current generated in the induction subcoil 5 is connected through the induction subcoil 5 and the lead wire 6. With the configuration in which the sub-deflection magnetic field is generated by supplying the magnetic flux generating sub-coil 7 wound around the magnetic iron core 8 at the opening end on the screen side, the vertical raster pincushion distortion can be stably and easily corrected. .

[0020]

As is apparent from the above description, the present invention includes an induction subcoil disposed outside the vertical deflection coil,
The configuration with a magnetic flux generating sub-coil wound around a magnetic iron core arranged at the opening end on the screen side connected to the induction sub-coil through a lead wire enables stable and easy correction of upper and lower raster pincushion distortion. It is possible to realize an excellent deflection yoke.

[Brief description of drawings]

FIG. 1 is a schematic side view of a deflection yoke according to an embodiment of the present invention.

FIG. 2 is a schematic top view of the deflection yoke.

FIG. 3 is a side view of an enlarged main part of the deflection yoke.

FIG. 4A is a characteristic diagram of vertical deflection current of a magnetic flux generating sub-coil of the same deflection coil, FIG. 4B is a characteristic diagram of induced electromotive force of the magnetic flux generating sub-coil, and FIG. Current characteristic diagram

FIG. 5 is a top view of essential parts showing a sub-deflection magnetic field generated by an induction current supplied to a magnetic flux generation sub-coil of the same deflection coil.

FIG. 6A is a top view of a main part showing the force received by an electron beam by the magnetic flux generating subcoil. FIG. 6B is a state diagram of the upper and lower raster pin cushions of the deflection yoke.

FIG. 7 is a schematic side view of a conventional deflection yoke.

FIG. 8 is a schematic top view of the deflection yoke.

FIG. 9 is a main part top view showing a force received by an electron beam by a permanent magnet of the deflection yoke.

[Explanation of symbols]

 2 Vertical deflection coil 3 Core 5 Induction sub-coil 6 Lead wire 7 Magnetic flux generation sub-coil 8 Magnetic iron core

Claims (1)

[Claims] 1. A deflection yoke having a horizontal deflection coil and a vertical deflection coil disposed on a magnetic core, the induction sub-coil disposed outside the vertical deflection coil, the induction sub-coil and a lead wire. A deflection yoke, comprising: a magnetic flux generating sub-coil wound around a magnetic iron core disposed at an opening end on the screen side connected through