JP2001160364A - Deflection yoke and display unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the defect where performance demanded for the deflection yoke becomes unsatisfied due to spreading flat type color picture tunes being used in a display, because optimized distortion of vertical pins at middle portion of the screen causes increased magnetic field strength at the periphery to give a barrel distortion with the vertical distortion being greater. SOLUTION: Centers of the first magnets 1a are located in a position parallel to Y-axis, and one in the positive region of Y has disposed S pole in the positive and N pole in the negative of X, and the other in the negative region of Y has disposed N pole in the positive and S pole in the negative of X. Furthermore, centers of the second magnets 1b are located in a position parallel to Y-axis and more distant from Z axis than centers of the first magnets 1a are, and one in the positive region of Y has disposed S pole in the positive side and N pole in the negative of X, and the other in the negative region of Y has disposed N pole in the positive side and S pole in the negative side of X.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to elimination of magnetic field distortion of a deflection yoke used in a color cathode ray tube and correction of vertical distortion of a screen of a display device using the deflection yoke.

[0002]

2. Description of the Related Art FIG. 10 is a view for explaining vertical pin distortion in a conventional display device. In the figure, 1
2 is a cathode ray tube, 10 is a deflection yoke attached to the cathode ray tube 12, 11 is a deflection center where an electron beam in the cathode ray tube is deflected by the deflection yoke 10, 1 is a correction magnet provided in the deflection yoke 10. The X axis of the rectangular coordinates is the horizontal direction, the Y axis is the vertical direction, the Z axis is the tube axis of the cathode ray tube 12, and the axis of the deflection yoke 10. Further, in the figure, the panel portion is shown obliquely from behind, seeing through the cathode ray tube.

Usually, in the cathode ray tube 12, the deflection yoke 10 forms a raster 13 by deflecting the electron beam. However, the inner surface of the panel of the cathode ray tube 12 which is a fluorescent screen is almost flat, so that the panel of the cathode ray tube 12 is Is larger than the axial distance (a) from the deflection center 11 of the deflection yoke 10 to the panel of the cathode ray tube 12. FIG.
Is a view showing the screen of the cathode ray tube 12, and the raster on the screen viewed from the outer surface is distorted into a pincushion near the center on the Y axis (hereinafter, referred to as "pin distortion").

FIG. 12 is a front view and a side view of a general deflection yoke in which the above-mentioned vertical distortion has been corrected. In the drawing, reference numeral 4 denotes an opening on the panel side and the electron gun side of the cathode ray tube, and a separator formed substantially axially symmetric with respect to the tube axis of the cathode ray tube. A horizontal deflection coil 3 is a pair of upper and lower vertical deflection coils attached to a separator 4, and 1 is disposed in a panel opening of the separator 4 and has magnetic poles in the same direction as the circumferential direction around the tube axis and the tube. It is a pair of upper and lower magnets that are axially symmetric with respect to the axis. Also, the X axis is positive in the horizontal direction on the left side of the screen, the Y axis is positive on the screen in the vertical direction, the Z axis is the same as the tube axis, and the screen direction is positive. With the above configuration, the upper and lower pin distortion is corrected by the magnetic field of the magnet 1.

FIG. 13 is a diagram showing the operation of the magnet 1 as viewed from the screen direction of the cathode ray tube 12. In the positive region of Y, the magnet 1 is arranged at the positive pole of X and at the south pole, at the negative pole of X at the north pole, and at the negative region of Y, at the positive pole of X and at the negative pole of X. This magnetic field is generated from the north pole to the south pole of the magnet 1,
The electron beam receives a force in the Y-axis direction toward the magnet 1 according to Faraday's law to correct vertical pin distortion.

FIG. 14 is a diagram showing the magnetic field strength of the magnet 1. In the figure, the magnetic field is stronger in the portion closer to the magnet 1 and the shape and the mounting position of the pair of upper and lower magnets 1 are adjusted so that the vertical distortion of the entire screen is depressed so that the horizontal line is in the best condition without undulation. It is.

[0007]

In recent years, the size of a color picture tube (hereinafter referred to as a cathode ray tube) used for a display device has been increased.
As the angle of view becomes wider and flatter, the distance a in FIG.
And the distance b is large, and the pin-shaped vertical distortion on the screen is also large in the middle part of the screen. Therefore, the optimization of the correction by the magnet 1 alone as shown in FIG. Is optimized, the upper and lower pin distortion is insufficiently corrected in the middle portion of the screen because the magnetic field strength of the magnet is weak. As shown in FIG. 16, if the upper and lower pin distortions in the middle part are optimized, the magnetic field strength of the magnet is strong in the peripheral part, so that the upper and lower pin distortions are large, and conversely to the pin distortion, the vicinity of the Y axis is larger than the screen peripheral part Deflected barrel distortion results in a phenomenon that the performance required for the deflection yoke cannot be satisfied.

FIG. 17 shows a deflection yoke described in JP-A-6-283115. In addition to the magnet 1, two magnets 5a, 5 whose magnetic poles are parallel to the XY plane
b and magnets 6a, 6b, 6c whose magnetic poles are parallel to the Z axis,
Although the distortion on the screen is corrected in 6d, the types, quantities, and arrangement positions of the magnets to be used are large, which causes an increase in variation in mass production and a new factor of failure.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is intended to reduce the number and types of magnets.
It is an object of the present invention to provide a deflection yoke and a display device that effectively correct image distortion on a screen due to flattening of the screen.

[0010]

The deflection yoke according to the present invention is arranged on the panel side of the vertical deflection coil of the separator, and the magnetic poles are arranged in the same direction as the circumferential direction around the tube axis and on the tube axis. It comprises a pair of upper and lower first magnets which are axially symmetric with respect to each other, and a second magnet which is located on an outer periphery of the first magnet and corrects a magnetic field distortion generated by the first magnet. .

Further, the second magnet is arranged in a pair of upper and lower sides and at the opposite magnetic pole to the first magnet.

Further, the second magnet is arranged on the same plane as the first magnet.

Further, the second magnet is arranged closer to the panel than the first magnet.

Further, the second magnet is located at the upper right,
The magnetic poles are located at the lower right, lower left, and upper left positions, and the magnetic poles are arranged in the same direction as the first magnet around the tube axis.

Further, a display device according to the present invention incorporates the deflection yoke according to the present invention.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a deflection yoke device according to the present invention will be described.

Embodiment 1 FIG. 1 is an external view of a deflection yoke according to an embodiment of the present invention. In the figure, reference numeral 4 denotes a separator having openings on the panel side and the electron gun side of the cathode ray tube, and formed substantially axially symmetric with respect to the tube axis of the cathode ray tube;
Reference numeral 2 denotes a pair of left and right horizontal deflection coils attached to the separator 4, reference numeral 3 denotes a pair of upper and lower vertical deflection coils attached to the separator 4, and the magnet 1 a is disposed closer to the panel than the vertical deflection coil 3 of the separator 4. A pair of upper and lower first magnets, 1b, which are in the same direction as the circumferential direction about the tube axis and are axially symmetric with respect to the tube axis, are located on the outer periphery of the first magnet 1a, and the first magnets 1
7 is a second magnet for correcting the distortion of the magnetic field generated in FIG. The separator 4 of the molded product insulates the horizontal deflection coil 2 and the vertical deflection coil 3 from each other. The X axis is horizontal and the left side of the screen is positive, the Y axis is vertical and the screen is positive and the Z axis is a tube. The screen direction is the same as the axis, and the screen direction is positive.

Here, in order to correct pin distortion, the center of the first magnet 1a is located at a position parallel to the Y axis, and one of the magnetic poles of the first magnet 1a is located in the positive Y region. In the negative region of Y, the N pole is disposed in the negative region, and the other is disposed in the negative region of Y. Further, in order to correct barrel distortion generated in the first magnet 1a, the center of the second magnet 1b is parallel to the Y axis and is located away from the z axis from the center of the first magnet 1a. One in the region of X is a positive north pole of X and a negative S pole, and the other in a region of negative Y is a positive S pole of X and a negative N pole of X.

The operation of the present invention having the above configuration is as follows. The direction of the magnetic field generated by the first magnet 1a and the direction of the force applied to the electron beam by the magnetic field are as shown in FIG. In this case, the vertical distortion acts on the lower side, and the vertical distortion is corrected by reducing the pin distortion.

In the prior art, the shape and the mounting position were adjusted by the pair of upper and lower magnets so as to optimize the vertical distortion in the peripheral portion of the screen. However, in the present invention, the vertical distortion in the intermediate portion of the screen was adjusted as shown in FIG. Adjust the shape and the mounting position so that a little barrel distortion occurs.

At this time, the magnetic field of the first magnet 1a is
The closer to the first magnet 1a, the stronger the magnetic field, which has a large effect on the electron beam. Therefore, if the vertical distortion of the middle part of the screen is adjusted to be a little barrel distortion by the first magnet 1a, the magnet 1a will be affected. At a nearby peripheral portion of the screen, a large barrel distortion is caused by the influence of the stronger magnetic field, as shown in FIG.

Next, FIG. 4 shows the direction of the magnetic field by the second magnet 1b and the direction of the force applied to the beam by the magnetic field.
The influence on the beam is opposite to that of the first magnet 1a, and it acts in a direction of pushing down the beam (downward on the upper side of the screen and upward on the lower side) at the time of downward deflection, and vertical distortion becomes pin distortion.

However, the second magnet 1b is mounted farther from the Z axis, which is the center of the cathode ray tube 12, than the first magnet 1a. Since it acts when the image is deflected, it hardly affects the middle part of the screen. This is because the magnetic field of the magnet greatly affects the vicinity where the magnet is arranged.

Therefore, although the vertical distortion in the middle portion of the screen is made a little pin distortion, the vertical distortion in the peripheral portion of the screen in which the correction of the upper and lower pin distortion is overcorrected by the first magnet can be corrected in the pin distortion direction. It is possible to make the vertical distortion of the entire screen horizontal as shown in FIG.

As shown in FIG. 6, the second magnet 1b
Are disposed closer to the panel than the first magnet 1a. With this arrangement, the magnetic field of the second magnet 1b acts on the electron beam deflected to the peripheral portion of the screen, so that only vertical distortion can be effectively suppressed, and the intermediate portion distortion is more effectively prevented. It is effective.

In optimizing the magnetic field shapes of the first magnet 1a and the second magnet 1b, magnetic pieces 7 may be attached to both ends of the magnet as shown in FIG.

Embodiment 2 FIG. FIG. 8 shows another embodiment of the second magnet 1b. In the figure, the second magnet 1b is located at four locations near the diagonal near the panel-side opening of the separator 4, at the upper right, lower right, lower left, and upper left, and the magnetic poles are connected to the first magnet 1a and the tube axis. It is arranged in the same direction at the center. Further, the magnetic poles are arranged from the N pole to the S pole in the rotation direction of the right-hand screw that advances in the Z-axis direction,
The direction is the same as that of the first magnet 1a.

FIG. 9 is a diagram showing the magnetic field of the second magnet 1b and the force applied to the electron beam by the magnetic field. In the figure, at the upper left of the screen (first quadrant on the XY plane), when the electron beam is deflected diagonally, it is subjected to a force in the direction of pulling up in the upper left diagonal direction by the magnetic field of the second magnet 1b. Also in the second, third and fourth quadrants, the electron beam near the diagonal of the screen receives a force in the diagonal direction to be pulled up by the magnetic field of the second magnet 1b located at the diagonal position.

Therefore, the vertical distortion is optimized near the center of the screen by the first magnet 1a, but barrel distortion occurs near the Y-axis where the first magnet 1a is arranged near the screen. By raising the electron beam in the diagonal direction of the screen with the magnetic field of the second magnet 1b, the vertical distortion around the screen can be adjusted, and the vertical distortion over the entire screen can be optimized (horizontal).

Further, since the display in which the deflection yoke 10 according to the present invention is incorporated in the cathode ray tube 12 has no vertical distortion of the electron beam, there is no need to mount a correction circuit for removing vertical distortion, and a good image can be obtained.

[0031]

Since the present invention is configured as described above, it has the following effects.

A pair of upper and lower first magnetic poles are disposed on the panel side of the vertical deflection coil of the separator, and the magnetic poles are in the same direction as the circumferential direction around the tube axis and are axially symmetric with respect to the tube axis.
And correcting the barrel distortion of the magnetic field generated by the first magnet by the magnet and the second magnet positioned on the outer periphery of the first magnet and correcting the magnetic field distortion generated by the first magnet. Can be.

In addition, since the second magnets are arranged in a pair of upper and lower magnetic poles opposite to the first magnet, barrel distortion can be reliably corrected with a small number of magnets.

Further, since the second magnet is arranged on the same plane as the first magnet, it can be mounted with high accuracy.

Further, since the second magnet is disposed closer to the panel than the first magnet, it is possible to generate a magnetic field that effectively suppresses only vertical distortion, and it is possible to prevent the intermediate part from being deteriorated. More effective.

Further, the second magnet is located at the upper right,
Located at the lower right, lower left, and upper left locations, the magnetic poles are arranged in the same direction around the tube axis as the first magnet, so the electron beam is pulled up diagonally to adjust the vertical distortion around the screen Then, a magnetic field is generated so as to make the vertical distortion over the entire screen the best (horizontal).

Further, the display device according to the present invention has the best (horizontal) vertical distortion over the entire screen area by incorporating the deflection yoke according to the present invention.

[Brief description of the drawings]

FIG. 1 is an external view of a deflection yoke according to a first embodiment.

FIG. 2 is a diagram illustrating a magnetic field and an electromagnetic force of a first magnet according to the first embodiment.

FIG. 3 is a diagram showing a vertical distortion pattern after correction by a first magnet in the first embodiment.

FIG. 4 is a diagram showing a magnetic field and an electromagnetic force of a second magnet in the first embodiment.

FIG. 5 is a vertical distortion pattern after correction in the first embodiment.

FIG. 6 is a diagram showing an effective magnet positional relationship in the first embodiment.

FIG. 7 is an external view in which a magnetic piece is attached to the magnet of the first embodiment.

FIG. 8 is an external view of a deflection yoke according to the second embodiment.

FIG. 9 is a diagram illustrating a magnetic field and an electromagnetic force of a second magnet according to the second embodiment.

FIG. 10 is a diagram showing that flattening of a cathode ray tube causes upper and lower pin distortion.

FIG. 11 is a diagram showing vertical pin distortion.

FIG. 12 is a view showing a conventional deflection yoke.

FIG. 13 is a diagram showing a magnetic field and an electromagnetic force of a conventional magnet.

FIG. 14 is a diagram showing the magnetic field strength of a magnet.

FIG. 15 is a diagram showing a vertical distortion pattern 1 generated by a conventional magnet correction.

FIG. 16 is a diagram showing a vertical distortion pattern 2 generated by conventional magnet correction.

FIG. 17 is a view showing a deflection yoke described in JP-A-6-283115.

[Explanation of symbols]

1: magnet, 1a first magnet, 1b
2nd magnet, 2 horizontal deflection coils, 3 vertical deflection coils, 4 separators, 7 magnetic pieces.

Claims (6)

[Claims] 1. A separator having openings on the panel side and the electron gun side of a cathode ray tube, formed substantially axially symmetrically with respect to the tube axis of the cathode ray tube, and a pair of upper and lower vertical members attached to the separator. A deflection yoke having a deflection coil and a pair of left and right horizontal deflection coils, wherein the separator is disposed closer to the panel than the vertical deflection coil, and a magnetic pole is in the same direction as a circumferential direction around the tube axis and the tube A pair of upper and lower first members that are axisymmetric with respect to the axis
And a second magnet positioned on the outer periphery of the first magnet and correcting distortion of a magnetic field generated by the first magnet. 2. The deflection yoke according to claim 1, wherein the second magnets are arranged on a pair of upper and lower sides and opposite magnetic poles to the first magnets. 3. The deflection yoke according to claim 2, wherein the second magnet is arranged on the same plane as the first magnet. 4. The deflection yoke according to claim 2, wherein the second magnet is disposed closer to the panel than the first magnet. 5. The method according to claim 1, wherein the second magnet is located at the upper right, lower right,
The deflection yoke according to claim 1, wherein the magnetic poles are located at four lower left and upper left positions, and the magnetic poles are arranged in the same direction about the tube axis as the first magnet. 6. A display device, wherein the deflection yoke according to claim 1 is incorporated in a cathode ray tube.