JP2001222964A - Deflection yoke and display device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a deflection yoke and a display device equipped with the deflection yoke enabling improvement of the quality level of displayed pictures. SOLUTION: The deflection yoke comprises one pair of horizontal deflection coils generating a horizontal deflection magnetic field deflecting the electron beam in a horizontal axis H direction, one pair of vertical deflection coils 11a and 11b generating a vertical deflection magnetic field deflecting the electron beam in a vertical axis V direction, a ferrite core 12 made of a magnetic material, one pair of compensating magnets 16a and 16b generating a compensating magnetic field to compensate the orbit of the electron beam and a guide structure 15 capable of moving the compensating magnet in the horizontal axis direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a deflection yoke and a display device using the same, and more particularly, to a deflection yoke mounted on a cathode ray tube for displaying an image.

[0002]

2. Description of the Related Art In recent years, a display device has a large screen and a flat screen. In particular, when the screen is flattened, the conventional deflection yoke has a problem that the raster distortion becomes large and sufficient correction cannot be performed.

As shown in FIGS. 6 and 7, a conventional deflection yoke 50 comprises a pair of upper and lower (on a vertical axis V) horizontal deflection coils mounted inside an injection-molded mold 51 and an outer side of the mold 51. A pair of left and right (on the horizontal axis H) vertical deflection coils 53a and 53b, a ferrite core 54 formed of a magnetic material, and a pair of upper and lower correction magnets 55a and 55b for correcting raster distortion.
A pair of upper and lower correction elements 56 for correcting the convergence of the electron beam is provided.

Referring to FIGS. 8 and 9, the principle of the conventional deflection yoke 50 for correcting raster distortion will be described.
9, it is assumed that the horizontal deflection magnetic field 70 is formed by an ideal pair of horizontal deflection coils 57a and 57b formed symmetrically with respect to the vertical axis V, and is rotated clockwise around the tube axis Z. In addition, it is assumed that they are not inclined in the counterclockwise rotation direction, and illustration of the action of the magnetic field in the third and fourth quadrants is omitted for convenience.

[0005] As shown in FIG. 8, in particular, it is assumed that a pincushion-type raster distortion 61 extending near a diagonal to the reference frame 60 is generated on a flat screen. . In FIG. 8, the electron beam 72 directed to the screen diagonal receives the Lorentz force FA1, as shown in FIG. Since the horizontal deflection magnetic field 70 formed by the pair of horizontal deflection coils 57a and 57b is of a pincushion type, the Lorentz force FA1 has a vertical component FA1v acting downward in the vertical axis V direction. For this reason, the Lorentz force FA1 acts on the electron beam 72 toward the screen diagonal in the direction of the arrow 80, that is, in the downward direction of the vertical axis V, as shown in FIG. Similarly, for the electron beam directed to the screen diagonal in the second quadrant, the Lorentz force F
A2 acts downward in the direction of arrow 81, that is, in the vertical axis V direction.

The electron beam 73 traveling toward the end of the vertical axis V
Receives the Lorentz force Fm by the correction magnetic field 71 formed by the correction magnet 55a. The Lorentz force Fm acts on the electron beam 73 traveling toward the end of the vertical axis V in an upward direction in the vertical axis V as shown in FIG.

In other words, the conventional deflection yoke 50 applies a downward Lorentz force on the electron beam directed to the diagonal of each quadrant in the direction of the vertical axis V, and applies an electron beam directed toward the vicinity of the vertical axis V to the electron beam. The raster distortion is corrected by applying an upward Lorentz force in the vertical axis V direction.

In the meantime, the horizontal deflection coil rotates a metal mold composed of a male mold and a female mold, and at the same time, winds an electric wire in a gap between the male mold and the female mold, or fixes the mold so that the male mold is fixed to the male mold. It is formed by winding an electric wire in the gap with the female mold. For this reason, as shown in FIG. 10, the shape of the coil depends on the conditions under which the wire enters the gap of the mold, for example, conditions such as the rotation speed and the wire diameter of the wire. May be different. At this time, the coil has an asymmetric shape with respect to the vertical axis V.

When such coils having an asymmetric shape with respect to the vertical axis V are arranged symmetrically with respect to the horizontal axis H as shown in FIG. 11, the horizontal deflection coils 57a and 57b generate a horizontal deflection coil. The magnetic field forms a pincushion-type magnetic field distribution 58 inclined at a predetermined angle counterclockwise about the tube axis Z.

Therefore, a display image displayed on the screen by the electron beam deflected by the deflection magnetic field 58 has raster distortions 75 and 75 in the first and third quadrants as shown in FIG. It becomes larger than the raster distortions 76 and 77 in the second and fourth quadrants, resulting in poor balance.

Further, in a display device in which one phosphor screen is divided into a plurality of regions and scanned by electron beams emitted from a plurality of electron gun assemblies, as shown in FIG. At the center of the portion 85, an area where no image is displayed may be formed, or an area where a plurality of images overlap at a part of the boundary 85 may be formed. For this reason, the quality of the display image may be reduced.

[0012]

As described above, due to a manufacturing error of the horizontal deflection coil and a mounting error when the horizontal deflection coil is mounted on the holding mold, the horizontal deflection coil is moved with respect to each of the horizontal axis H and the vertical axis V. A magnetic field distribution inclined about the tube axis Z so as to be asymmetric is formed. As a result, the balance of the amount of correction of the raster distortion is lost, and there is a problem that the quality of the displayed image is reduced.

[0013] Even in a deflection yoke having a normal horizontal deflection coil, an electron beam emitted from the electron gun assembly and the horizontal deflection coil due to a mounting error when the electron gun assembly is mounted on the neck of the envelope. Due to the relative displacement with respect to the horizontal deflection magnetic field formed by this, a magnetic field distribution inclined with respect to the electron beam acts, causing a problem that the quality of the displayed image is degraded.

Further, in a display device in which one phosphor screen is divided into a plurality of regions and scanned by electron beams emitted from a plurality of electron gun assemblies, a defect occurs in a displayed image at a boundary portion of the image. This causes a problem of deteriorating the quality of the displayed image.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described problems, and has as its object to provide a deflection yoke capable of improving the quality of a display image and a display device including the deflection yoke. It is in.

[0016]

According to another aspect of the present invention, there is provided a deflection yoke including a pair of horizontal deflection magnetic fields for generating a horizontal deflection magnetic field for deflecting an electron beam in a horizontal axis direction. A coil, a pair of vertical deflection coils for generating a vertical deflection magnetic field for deflecting the electron beam in the vertical axis direction, a ferrite core formed of a magnetic material, and a pair of corrections for generating a correction magnetic field for correcting the trajectory of the electron beam. And a guide mechanism capable of moving the correction magnet in parallel along the horizontal axis direction.

According to a second aspect of the present invention, an electron gun assembly for generating an electron beam, a neck for enclosing the electron gun assembly, a panel having a phosphor screen therein, and the neck and the panel are connected. An envelope having a funnel, a deflection yoke mounted on an outer surface of the funnel,
Wherein the deflection yoke includes a pair of horizontal deflection coils for generating a horizontal deflection magnetic field for deflecting the electron beam in the horizontal axis direction, and a pair of horizontal deflection coils for generating a vertical deflection magnetic field for deflecting the electron beam in the vertical axis direction. A vertical deflection coil,
A ferrite core formed of a magnetic material, a pair of correction magnets for generating a correction magnetic field for correcting the trajectory of the electron beam, and a guide mechanism capable of moving the correction magnet in parallel along the horizontal axis direction. It is characterized by the following.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a deflection yoke according to an embodiment of the present invention;

As shown in FIG. 1, a display device having a deflection yoke according to the present invention, that is, a color cathode ray tube device is provided with an in-line type electron gun assembly which emits three electron beams arranged in a row in the horizontal direction H. I have.

This color cathode ray tube apparatus includes a panel 101
, A neck 105, and a funnel 102 connecting the panel 101 and the neck 105.

The panel 101 is formed in a substantially rectangular shape having a major axis in the horizontal direction H and a minor axis in the vertical direction V, and has red (R), green (G), and blue (B) light-emitting surfaces on its inner surface. And a phosphor screen 103 composed of a striped or dot-shaped three-color phosphor layer and a metal back layer. Further, this color cathode ray tube device has a shadow mask 104 mounted at a position facing the phosphor screen 103 at a predetermined interval. The shadow mask 104 has a large number of apertures inside the shadow mask 104 for passing an electron beam.

The neck 105 is formed in a substantially cylindrical shape having a central axis coinciding with the tube axis Z, and has a substantially circular cross-sectional shape of the inside diameter. The neck 105 has three electron beams 106B and 106 arranged in a line in a line on the same horizontal plane.
An electron gun structure 107 for emitting G and 106R is provided.

These three electron beams 106G, 106B,
106R are arranged in a row in the horizontal direction H, and are discharged along a direction parallel to the tube axis direction Z. Of the three electron beams,
The electron beam 106G as the center beam travels on the trajectory closest to the center axis of the neck 105. Also,
Electron beams 106B, 10 as a pair of side beams
6R travels on the trajectory of both sides of the center beam 106G.

The electron gun assembly 107 focuses the three electron beams 106R, 106G, and 106B on the phosphor screen 103, and at the same time,
The three electron beams converge on the phosphor screen 103 surface.

This color cathode ray tube device has a deflection yoke 108 mounted outside the funnel 102 and an external conductive film 113 formed outside the funnel 102.
And an internal conductive film 117 formed on the inner surface extending from the funnel 102 to a part of the neck 105. The internal conductive film 117 is electrically connected to an anode terminal for supplying an anode voltage.

In the color cathode ray tube device having such a structure, the three electron beams 10 emitted from the electron gun
6B, 106G, and 106R are deflected while self-concentrating by a non-uniform magnetic field including a pincushion-type horizontal deflection magnetic field and a barrel-type vertical deflection magnetic field generated by a deflection yoke 108, The screen 103 is scanned in the horizontal direction H and the vertical direction V. Thereby, a color image is displayed.

As shown in FIGS. 2 and 3, a deflection yoke 108 applied to this color cathode ray tube apparatus has a pair of vertical deflection coils 11a and 11b for forming a vertical deflection magnetic field.
And a ferrite core 12 formed of a magnetic material;
Holding mold 1 formed by injection-molded resin
3, a pair of correction elements 14a and 14b for forming a correction magnetic field mainly for correcting convergence, and a pair of correction magnets 1 formed in a rod shape for mainly correcting raster distortion.
6a and 16b.

The holding mold 13 is formed in a substantially conical shape with the tube axis Z as the central axis. In addition, holding mold 1
Numeral 3 holds a pair of horizontal deflection coils arranged on the inner vertical axis V so as to face each other.

Vertical deflection coils 11a and 11b, and
The horizontal deflection coil rotates a metal mold composed of a male mold and a female mold processed into a predetermined shape, and at the same time, winds an electric wire in the gap between the male mold and the female mold, or fixes the mold to the male mold. The wire is wound around the gap between the female and female molds to form saddles. These vertical deflection coils 11a and 11b are arranged on the horizontal axis H outside the holding mold 13 so as to face each other.

The ferrite core 12 is used for the vertical deflection coil 1.
In order to prevent the deflection magnetic field formed by 1a and 11b from leaking outside, it is arranged so as to surround the vertical deflection coils 11a and 11b along the side surface of the holding mold 13.

The correction elements 14a and 14b are electromagnetic coils formed by winding electric wires around a U-shaped silicon steel plate. The pair of correction elements 14a and 14b are arranged at symmetric positions so as to face each other on the vertical axis V.

The holding mold 13 is provided with a correction magnet 16
a and 16b as well as the correction magnet 16
and a guide mechanism 15 capable of moving the a and 16b in parallel along the horizontal axis H direction. The guide mechanism 15 includes a plurality of fins 15a, 15b extending in the horizontal axis H direction.
15c and 15d are provided. The distance between these fins is substantially equal to the outer shape of the rod-shaped correction magnet. In the example shown in FIG. 3, a pair of correction magnets 16a and 16b
Is disposed between the first fin 15a and the second fin 15b, but may be disposed between the second fin 15b and the third fin 15c as necessary, for example, when adjusting the correction amount, and It is also possible to attach a correction magnet between 15c and the fourth fin 15d.

As shown in FIG. 4A, the pair of horizontal deflection coils 17a and 17b may have an HV error due to a manufacturing error, a mounting error, or a relative position error with respect to the electron gun assembly 107. When arranged asymmetrically about the vertical axis V in the plane, these horizontal deflection coils 11a and 1a
The pincushion-type horizontal deflection magnetic field 20 formed by 1b has a distribution inclined in the counterclockwise direction 41 about the tube axis Z.

As shown in FIG. 5, the raster distortions 44 and 45 caused by the electron beams deflected diagonally in the first and third quadrants by the inclined horizontal deflection magnetic field as described above, as shown in FIG.
Are larger than the raster distortions 46 and 47 due to the electron beams deflected diagonally in the second and fourth quadrants, and even if a correction magnet for correcting the raster distortion is fixedly provided on the vertical axis V. However, the balance of raster distortion cannot be improved.

FIG. 4B is a principle diagram for improving the balance of raster distortion. FIG. 4B shows the vertical axis V with respect to the horizontal deflection magnetic field 20 inclined in the counterclockwise rotation direction.
The correction magnet 14a disposed on the upper side of the upper
Along the left side of the drawing along the arrow shows a state where the object is translated by a predetermined slide amount. The electron beam is assumed to be traveling from the back side of the paper to the front side. In addition,
In FIG. 4B, the third and fourth quadrants are omitted.

The electron beam 30 deflected toward the diagonal of the first quadrant of the screen is affected by both the inclined horizontal deflection magnetic field 20 and the correction magnetic field 21 formed by the correction magnet 14a. The Lorentz force F1 received from the horizontal deflection magnetic field 20 includes a horizontal component F1h and a vertical component F1v
And is decomposed into The Lorentz force M1 received from the correction magnetic field 21 is decomposed into a horizontal component M1h and a vertical component M1v. Therefore, the position at which the electron beam that reaches the diagonal of the first quadrant reaches the screen is determined by the resultant force of the vertical components F1v and M1v.

Similarly, the electron beam 30 deflected toward the diagonal of the second quadrant of the screen also has a tilted horizontal deflection magnetic field 20.
And the correction magnetic field 21 formed by the correction magnet 14a. The Lorentz force F2 received from the horizontal deflection magnetic field 20 is decomposed into a horizontal component F2h and a vertical component F2v. The Lorentz force M2 received from the correction magnetic field 21 includes a horizontal component M2h and a vertical component M2.
and v. Therefore, the position at which the electron beam traveling toward the diagonal of the second quadrant reaches the screen is determined by the vertical component F
It is determined by the resultant force of 2v and M2v.

As shown in FIG. 4B, by moving the correction magnet 14a to the left side in parallel, the Lorentz force acting on each electron beam toward the diagonal of the first quadrant and the second quadrant is reduced. The vertical components M1v and M2v satisfy M2v> M1v. Therefore, in the second quadrant, the electron beam is mainly affected by the correction magnetic field 21 more than the horizontal deflection magnetic field 20. In the second quadrant, especially for an electron beam deflected near the diagonal, the correction magnetic field 21
Lorentz force acts upward in the vertical axis V direction. Therefore, as shown in FIG. 5, the raster distortion 46 in the second quadrant can be improved.

On the other hand, in the first quadrant, the electron beam is largely affected mainly by the horizontal deflection magnetic field 20. In the first quadrant, the Lorentz force due to the horizontal deflection magnetic field 20 acts downward on the vertical axis V particularly for an electron beam deflected near the diagonal. Therefore, as shown in FIG. 5, the raster distortion 44 in the first quadrant can be improved.

The vertical component of the horizontal deflection magnetic field 20 hardly occurs for the electron beam 33 traveling near the end of the vertical axis V. Further, the correction magnetic field 21 formed by the correction magnet 14a has a small gradient of the magnetic field even when the correction magnet 14a is moved in parallel along the horizontal axis H, so that the horizontal component of the Lorentz force Fv is small and almost the vertical component. Becomes For this reason, the electron beam is largely deflected upward in the vertical axis V direction more than the electron beam traveling near the diagonal portions of the first and second quadrants. Therefore, as shown in FIG. 5, raster distortion near the vertical axis V can be improved.

As shown in FIGS. 4A and 4B, when the horizontal deflection magnetic field 20 is tilted in the counterclockwise rotation direction, the correction magnet 14 disposed on the lower side on the vertical axis V
b forms a correction magnetic field that improves raster distortion with respect to the electron beam deflected in the third and fourth quadrants by being translated in a direction opposite to the correction magnet 14a along the horizontal axis H direction. I do.

That is, in the third quadrant, as in the first quadrant, the electron beam is largely affected mainly by the horizontal deflection magnetic field 20. In the third quadrant, especially for the electron beam deflected near the diagonal, the horizontal deflection magnetic field 2
The Lorentz force due to 0 acts upward in the vertical axis V direction. Therefore, as shown in FIG. 5, the raster distortion 45 in the third quadrant can be improved.

In the fourth quadrant, similarly to the second quadrant, the electron beam is mainly affected by the correction magnetic field 21 more than the horizontal deflection magnetic field 20. In the fourth quadrant, the Lorentz force caused by the correction magnetic field 21 acts downward on the vertical axis V, particularly for an electron beam deflected near the diagonal. Therefore, as shown in FIG. 5, the raster distortion 47 in the fourth quadrant can be improved.

Therefore, it is possible to correct the unbalance of the raster distortion of the display image over the entire screen, and it is possible to improve the display quality.

Since the quality of a displayed image can be improved by the above-described correction, a display device that divides one phosphor screen into a plurality of regions by using electron beams emitted from a plurality of electron gun assemblies and scans the screen. In this case, it is possible to improve the problem at the boundary between a plurality of images.

[0046]

As described above, according to the present invention, it is possible to provide a deflection yoke capable of improving the quality of a display image and a display device having the deflection yoke.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing the structure of a display device provided with a deflection yoke according to the present invention.

FIG. 2 is a side view schematically showing a structure of a deflection yoke according to the present invention.

FIG. 3 is a rear view of the deflection yoke shown in FIG. 2;

FIG. 4A is a diagram for explaining the inclination of the horizontal deflection magnetic field due to a manufacturing error of the horizontal deflection coil, and FIG. 4B is a view for explaining the correction of the inclination of the horizontal deflection magnetic field. FIG.

FIG. 5 is a diagram for explaining improvement of unbalanced raster distortion;

FIG. 6 is a side view showing a structure of a conventional deflection yoke.

FIG. 7 is a rear view showing the structure of the deflection yoke shown in FIG. 6;

FIG. 8 is a diagram for explaining a principle in which a conventional deflection yoke corrects raster distortion.

FIG. 9 is a diagram showing a magnetic field generated by a conventional deflection yoke.

FIG. 10 is a plan view showing the shape of a horizontal deflection coil.

FIG. 11 is a diagram for explaining a tilt of a horizontal deflection magnetic field formed by a horizontal deflection coil cut along the line AA in FIG. 10;

FIG. 12 is a diagram for explaining imbalance of raster distortion;

FIG. 13 is a view for explaining a defect of a display image at a boundary portion in a display device in which one phosphor screen is divided into a plurality of regions and scanned by electron beams emitted from a plurality of electron gun assemblies. FIG.

[Explanation of symbols]

 11 (a, b) vertical deflection coil 12 ferrite core 13 holding mold 14 (a, b) correction element 15 guide mechanism 15 (a, b, c, d) fin 16 (a, b) Correction magnet 17 (a, b) ... horizontal deflection coil

Claims (2)

[Claims] A pair of horizontal deflection coils for generating a horizontal deflection magnetic field for deflecting the electron beam in the horizontal axis direction; a pair of vertical deflection coils for generating a vertical deflection magnetic field for deflecting the electron beam in the vertical axis direction; A ferrite core formed by a body, a pair of correction magnets for generating a correction magnetic field for correcting the trajectory of the electron beam, and a guide mechanism capable of moving the correction magnet in parallel along the horizontal axis direction. A deflection yoke. 2. An electron gun assembly for generating an electron beam, an envelope having a neck for enclosing the electron gun assembly, a panel provided with a phosphor screen therein, and a funnel connecting the neck and the panel. A deflection yoke mounted on an outer surface of the funnel, wherein the deflection yoke includes a pair of horizontal deflection coils for generating a horizontal deflection magnetic field for deflecting the electron beam in a horizontal axis direction; A pair of vertical deflection coils that generate a vertical deflection magnetic field that deflects in the axial direction; a ferrite core formed of a magnetic material; a pair of correction magnets that generate a correction magnetic field that corrects the trajectory of the electron beam; A display device, comprising: a guide mechanism that can move in parallel along the horizontal axis direction.