JPH113672A - Convergence correction device - Google Patents

Abstract

(57) [Problem] To provide a convergence correction device capable of preventing a change in color purity, image distortion, and the like by reducing leakage magnetic flux from a permanent magnet. SOLUTION: One set of cores 13, 15 arranged linearly.
And a circular permanent magnet 7 rotatably provided between the pair of cores 13 and 15 to apply a bias magnetic field to the cores; and a magnetic field generated by a horizontal deflection current flowing around one of the cores 13 to generate a bias. Convergence including two coils L _S1 and L _{S2 in the} same direction as the direction of the magnetic field, and in which the magnetic field generated by the winding of the other core 15 and the flow of the horizontal deflection current is opposite to the direction of the bias magnetic field. In the correction device 11, one set of cores 13, 1
The permanent magnet 7 and a pair of cores 13, 15 are sandwiched between a pair of magnetic metal pieces 17, 17 in the same direction as the arrangement direction of the permanent magnet 7 and the permanent magnet 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a convergence correction device for correcting a symmetric vertical misconvergence at the X-axis end by applying a bias magnetic field to a core with a magnet.

[0002]

2. Description of the Related Art In a color cathode ray tube, it is known that symmetric vertical misconvergence occurs at the left and right ends of an X axis (horizontal scanning axis) as shown in FIG. To correct the symmetric vertical misconvergence at the X-axis end, for example, a convergence correction device 1 shown in FIG. 4 is used. The convergence correction device 1 has first and second cores 3 and 5 arranged linearly, and two sub-coils L _S1 and L _S2 wound around the first and second cores 3 and 5. As shown in FIG. 5, a deflection coil L _{H1 above} the tube axis of the cathode ray tube is connected in series to the sub coil L _S1 , while a deflection coil L _H2 below the tube axis is connected to the sub coil L _S2 in series. Circuits are further connected in parallel to supply a horizontal deflection current.

Each of the sub-coils L _S1 and L _S2 is wound so as to generate a reverse magnetic field. Also, the sub coil L
_A circular permanent magnet 7 is rotatably disposed between _S1 and L _S2 . Therefore, the permanent magnet 7 can change the bias magnetic field by moving the strongest magnetized portion. Further, the sub-coils L _S1 and L _S2 are arranged at an appropriate distance with the permanent magnet 7 interposed therebetween, so that
Magnetic fields generated when current flows do not interfere with each other.

Therefore, the magnetic field generated by the permanent magnet 7 is in the same direction in the sub-coils L _S1 and L _S2 . Then, when the beam scans to the right side of the screen and a current flows through the sub-coils L _S1 and L _S2 , the magnetic field generated by this causes the sub-coils L _S1 and L _S1
The direction is reversed with _S2 . Therefore, the sub coils L _S1 and L _S2
, One of the inductances is large and the other is small. As a result, the center of the deflection magnetic field is shifted upward or downward. Similarly, when scanning is performed on the left side of the screen, the center of the deflection magnetic field is shifted upward or downward. As a result, the directions of beam correction on the left and right sides of the screen are the same in the up and down directions, so that the symmetric vertical misconvergence at the X-axis end can be corrected, and the correction amount can be adjusted by rotating the permanent magnet 7.

[0005]

However, in the above-mentioned conventional convergence correction device, the permanent magnet is rotatably provided, and by rotating this permanent magnet, the bias magnetic field to the sub-coil is varied to reduce the convergence correction amount. For adjustment, there is a problem that the leakage magnetic field from the permanent magnet changes depending on the rotation angle, thereby changing the color purity on the cathode ray tube or affecting image distortion. The present invention has been made in view of the above circumstances, and provides a convergence correction device that can prevent changes in color purity and image distortion by reducing the leakage magnetic flux from the permanent magnet,
An object of the present invention is to improve the image quality of a color cathode ray tube.

[0006]

A convergence correction apparatus according to the present invention for achieving the above object is provided with a pair of linearly arranged cores and a rotatably provided core between the pair of cores. A circular permanent magnet for applying a bias magnetic field to a core, and a magnetic field generated by a horizontal deflection current wound around one of the cores is in the same direction as the direction of the bias magnetic field, and is wound around the other core. A convergence correction device comprising: two coils in which a magnetic field generated by the flow of a horizontal deflection current is in a direction opposite to the direction of the bias magnetic field. The pair of cores is sandwiched. Further, the convergence correction device is provided with the magnetic metal pieces on the upper and lower surfaces of the permanent magnet and a set of cores in a state where the rotation center axis of the permanent magnet is arranged in a horizontal direction, and along the circumference of the permanent magnet. A bent arc may be provided at the center of the magnetic metal piece.

In the convergence correction device configured as described above, the permanent magnet and one set of cores are sandwiched between a pair of magnetic metal pieces, and the leakage magnetic field from the permanent magnet that changes according to the rotation angle is reduced. In addition, since the arc portion bent along the circumference of the permanent magnet is provided at the center of the magnetic metal piece, the contact area between the magnetic metal piece and the permanent magnet is increased, and the torque required to rotate the permanent magnet is increased. Becomes stable.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a convergence correction device according to the present invention will be described below in detail with reference to the drawings. FIG. 1 is a structural view of a convergence correction device according to the present invention, and FIG. 2 is a view taken along the line AA in FIG. The same members as those shown in FIGS. 4 and 5 are denoted by the same reference numerals and described. Convergence correction device 11
Has first and second cores 13 and 15 arranged in a straight line, and two sub-coils L _S1 and L _S2 wound around the first and second cores 13 and 15. A deflection coil L _H1 (see FIG. 5) on the upper side of the cathode ray tube is connected in series to the sub coil L _S1 , while a deflection coil L _H on the lower side of the tube axis is connected to the sub coil L _S2.
H2 (see FIG. 5) are connected in series, and these series circuits are further connected in parallel to supply a horizontal deflection current.

Each of the sub-coils L _S1 and L _S2 is wound so as to generate a reverse magnetic field. Also, the sub coil L
A circular permanent magnet 7 magnetized in the direction of the magnetic field of the coil is rotatably disposed between _S1 and L _S2 . The magnetic field generated by the permanent magnet 7 is in the same direction in the first and second cores 13 and 15. The bias of the permanent magnet 7 can be changed by moving the strongest magnetized portion.
The sub-coils L _S1 and L _S2 are arranged at an appropriate distance from each other with the permanent magnet 7 interposed therebetween, so that the magnetic fields generated when current flows do not interfere with each other.

On the upper and lower surfaces of the permanent magnet 7 and the first and second cores 13 and 15 in a state where the rotation center axis of the permanent magnet 7 is horizontally arranged (the state of FIG. 1), a pair of magnetic metal pieces 17 are provided. 1
7 is provided. That is, the permanent magnet 7 and the first and second cores 13 and 15 are formed by the pair of magnetic metal pieces 17 and 17 parallel to the direction in which the permanent magnet 7 and the first and second cores 13 and 15 are linearly arranged. It is in a state of being sandwiched.
At the center of the magnetic metal pieces 17, 17, there is provided an arc portion 19 formed by bending along the circumference of the permanent magnet 7.
Reference numeral 9 has a spring property and holds the permanent magnet 7 therebetween. By providing the arc portion 19, the magnetic metal pieces 17, 17 and the arc portion 1
The contact area with 9 is larger than that of a flat plate.

The operation of correcting the symmetrical vertical misconvergence at the X-axis end in the convergence correction device 11 configured as described above is the same as the conventional one. That is, when a current flows through the sub-coils L _S1 and L _S2 when the beam scans to the right side of the screen, the magnetic field generated by this causes the sub-coils L _S1 and L _S2.
And in the opposite direction. For this reason, the sub-coils L _S1 , L
_{One of S2} has a large inductance and the other has a small inductance. As a result, the center of the deflection magnetic field is shifted upward or downward. Similarly, even when scanning is performed on the left side of the screen, the center of the deflecting magnetic field is shifted up or down, and the beam correction directions are the same in the left and right sides on the left and right sides of the screen.

The convergence correction device 11 adjusts the convergence correction amount by rotating the permanent magnet 7 to vary the bias magnetic field to the sub coil. At this time, if a leakage magnetic field is generated, the leakage magnetic field changes depending on the rotation angle of the permanent magnet 7, and the change in the leakage magnetic field changes the color purity on the cathode ray tube and affects image distortion. On the other hand, in the convergence correction device 11, since the permanent magnet 7 is sandwiched between the magnetic metal pieces 17, 17, the leakage magnetic field from the permanent magnet 7 is reduced, and the change in color purity and the influence on image distortion are eliminated. Further, an arc portion 19 having a spring property is formed on the permanent magnet 7, and this arc portion 1 is formed.
By holding the permanent magnet 7 at 9, the holding area of the permanent magnet 7 is increased, and the torque for rotating the permanent magnet 7 is stabilized. Further, by being sandwiched between the magnetic metal pieces 17, 17, the first and second cores 13, 15 become closed magnetic paths, and the inductance of the sub-coils L _S1 , L _S2 can be increased with a small number of turns.

As described above, according to the convergence correction device 11 described above, the permanent magnet 7 and the first and second cores 13,
Since the magnetic metal pieces 17 and 17 sandwiching the metal 15 are provided, the leakage magnetic field from the permanent magnet 7 can be reduced, and the change in color purity and image distortion of the cathode ray tube can be prevented. Further, since the periphery of the permanent magnet 7 is surrounded by the magnetic metal pieces 17, 17, the torque for rotating the permanent magnet 7 is stabilized, and the rotating torque of the permanent magnet 7 can be reduced. Furthermore, since the first and second cores 13 and 15 are closed magnetic circuits by providing the magnetic metal pieces 17 and 17, the inductance of the sub-coils L _S1 and L _S2 can be increased with a small number of turns, and the sub-coils L _S1 and L The efficiency of _S2 can be improved.

In the convergence correcting device 11 according to the above-described embodiment, the permanent magnet 7 and the first and second cores 13 and 15 with the rotation center axis of the permanent magnet 7 arranged in the horizontal direction are provided on the upper and lower surfaces. Although the case in which the pair of magnetic metal pieces 17 and 17 are provided has been described, the convergence correction device according to the present invention employs the permanent magnet 7 having the rotation center axis of the permanent magnet 7 arranged in the vertical direction and the first and second permanent magnets. Core 13, 15
A pair of magnetic metal pieces may be provided on the upper and lower surfaces. In this case, since the magnetic metal piece faces both circular side surfaces at both ends of the rotation center axis of the permanent magnet 7, it is not necessary to form the arc portion 19.

[0015]

As described above in detail, according to the convergence correction device according to the present invention, the permanent magnet and the
Since the set of cores is sandwiched between a pair of magnetic metal pieces, a leakage magnetic field can be reduced, and a change in color purity and image distortion of the cathode ray tube can be prevented. As a result, the image quality of the color cathode ray tube can be improved. In addition, if an arc portion bent along the circumference of the permanent magnet is provided at the center of the magnetic metal piece, the contact area between the magnetic metal piece and the permanent magnet increases, and the torque for rotating the permanent magnet decreases. It is stable, and the rotating torque of the permanent magnet can be reduced.

[Brief description of the drawings]

FIG. 1 is a structural diagram of a convergence correction device according to the present invention.

FIG. 2 is a view as viewed in the direction of arrows AA in FIG. 1;

FIG. 3 is an explanatory diagram of a symmetric vertical misconvergence at an X-axis end.

FIG. 4 is a structural diagram of a conventional convergence correction device.

FIG. 5 is a conventional convergence correction circuit diagram.

[Explanation of symbols]

7: permanent magnet, 11: convergence correction device, 1
3, 15: One set of cores, 17: Magnetic metal piece, 19: Arc part, L _S1 , L _S2 : Sub coil (coil)

Claims (2)

[Claims] 1. A pair of cores arranged in a straight line, a circular permanent magnet rotatably provided between the pair of cores and applying a bias magnetic field to the cores, and one of the cores wound around the core. The magnetic field generated by the flow of the horizontal deflection current is in the same direction as the direction of the bias magnetic field, and the magnetic field generated by the flow of the horizontal deflection current wound around the other core is opposite to the direction of the bias magnetic field. A convergence correction device comprising two coils, wherein the permanent magnet and the set of cores are sandwiched between a pair of magnetic metal pieces parallel to the straight line in the same direction. 2. A magnetic metal piece is provided on the upper and lower surfaces of the permanent magnet and a set of cores in a state where the rotation center axis of the permanent magnet is arranged in a horizontal direction, and the magnetic metal pieces are bent along the circumference of the permanent magnet. 2. The convergence correction device according to claim 1, wherein the circular arc portion is provided at a central portion of the magnetic metal piece.