JPH0666138B2 - Convergence correction device - Google Patents

Description

The present invention relates to a convergence correction device for correcting the convergence of a color cathode ray tube.

[Outline of Invention]

The present invention relates to a convergence correction device for correcting the convergence of a color cathode ray tube, in which two coils, which generate correction magnetic fields in opposite directions with respect to currents in the same direction, are wound around a convergence yoke, and a horizontal sawtooth current is provided in the direction. Accordingly, by changing the currents flowing through these two coils, a correction magnetic field equivalent to that when a parabolic current is passed through the convergence correction coil is generated,
It is designed to correct misconvergence.

[Conventional technology]

In the conventional in-line type color cathode ray tube, the deflection magnetic field is made special to correct the convergence, or the horizontal parabolic current is supplied to the convergence correction coil to perform the convergence correction.

[Problems to be solved by the invention]

However, by making the deflection magnetic field special, the cross-sectional shape of the electron beam is no longer circular, and due to this distortion,
The focus characteristic deteriorates and the image quality deteriorates. Therefore, in a graphic display, a high-accuracy monitor, and the like, which are required to have good focus characteristics, it is necessary to make the deflection magnetic field uniform.

When the deflection magnetic field is a uniform magnetic field, a misconvergence that changes in the horizontal direction can be corrected by causing a parabola current having a horizontal period to flow through the convergence correction coil.

However, in such a configuration in which the parabola current is passed through the convergence correction coil to correct the convergence, an external correction circuit for passing the parabola current through the convergence correction coil is required, and the configuration is complicated and expensive. .

Therefore, an object of the present invention is to provide a convergence correction device that can perform convergence correction by making the deflection magnetic fields uniform.

Another object of the present invention is to provide an inexpensive convergence correction device having a simple structure, which does not require a complicated external correction circuit for flowing a parabola current to the convergence correction coil.

[Means for solving problems]

According to the present invention, the first and second coils 11 and 12 are applied to the core to which the bias magnetic field is applied so that the bias magnetic fields to the first and second coils 11 and 12 are opposite to each other.
And the third and fourth coils 14 and 15 are wound around the convergence yoke, and the correction magnetic fields generated by the third coil 14 and the fourth coil 15 by the currents in the same direction are in opposite directions. So that the first coil 11 and the third coil 14 and the second coil 12 and the fourth coil 1
5 are connected in series, and the first and third coils 11 and 14 are connected.
Series connection and second and fourth coil series connection 12, 1
4 is a convergence correction device in which 4 are connected in parallel to supply a horizontal sawtooth current.

[Action]

Coils 14 and 15 that generate deflection magnetic fields in directions opposite to each other with respect to the direction of the sawtooth current are wound around the convergence yokes 21 and 22 in a bi-fara winding. The inductance of the coils 12 and 13 changes according to the direction of the sawtooth wave current supplied from the terminals 18 and 19, and the correction current flowing through the coils 14 and 15 is changed. As a result, the correction current flowing through the coil 14 and the correction current flowing through the coil 15 generate a correction magnetic field equivalent to that when a parabola current is passed through the convergence correction coil.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 1 is a U-shaped core, and the core 1 has magnetic legs 2 and 3. Reference numeral 4 denotes a T-shaped core, and the bottom surface of the core 4 is provided to shunt the leakage of the magnetic field to the outside. A magnetic leg 5 forming a magnetic path of the magnetic legs 2 and 3 of the core 1 is projected from the central portion of the bottom surface of the core 4. A magnet 7 is interposed between the magnetic leg 2 of the core 1 and one end of the core 4. Further, a magnet 8 is interposed between the magnetic leg 3 of the core 1 and the other end of the core 4.

A coil bobbin 10 around which a coil 12 is wound is attached to the magnetic leg 2. A coil bobbin 11 around which a coil 13 is wound is attached to the magnetic leg 3. These coil bobbins 10 and 11 are
The coils 12 and 13 are wound so that the directions of the bias magnetic fluxes are opposite to each other. The coils 12 and 13 are, as shown in FIG.
It is connected to the convergence correction coils 14 and 15.

That is, one end of the coil 12 is connected to the coil 14 via the terminal 23 derived from the coil 14, and one end of the coil 13 is connected to the coil 15 via the terminal 26 derived from the coil 15. The other ends of the coils 12 and 13 are commonly connected, and the terminal 18 is led out from this connection point. The terminal 24 derived from the coil 14 and the terminal 25 derived from the coil 15 are commonly connected, and the terminal 19 is connected from this connection point.
Is derived.

The convergence correction coil is constructed as shown in FIG.

In FIG. 3, 21 and 22 are convergence yokes provided so as to sandwich the neck portion 20 from the left and right.
Two coils 14 and 15 are wound around the convergence yokes 21 and 22 by bifilar winding. From the coil 14, terminals 23 and 24 are derived,
Terminals 25 and 26 are led out from the coil 15. When a current is passed from the terminal 23 to the terminal 24 or from the terminal 25 to the terminal 26, as shown in FIG. 3, a magnetic field for moving the side beams 27R and 27B to the outside is generated from the coil 14 or the coil 15.

In FIG. 2, by applying a horizontal sawtooth current through the terminals 18 and 19, a convergence correction current flows in the coils 14 and 15, which moves the side beams 27R and 27B, thereby moving the horizontal convergence of the screen. Is corrected.

That is, since the coil 14 and the coil 15 are connected as shown in FIG. 2, when a current is passed from the terminal 18 to the terminal 19, the coil 14 is fed from the terminal 23 to the terminal 24.
Current flows toward the side beam 2 from the coil 14.
A magnetic field is generated to move 7R and 27B outward. On the contrary, when a current flows from the terminal 19 to the terminal 18, a current flows through the coil 15 from the terminal 25 to the terminal 26, and the side beams 27R and 27B flow from the coil 15.
A magnetic field is generated that moves the to the outside.

Now, a current flows from the terminal 18 to the terminal 19, and at this time, as indicated by arrows A and B in FIG. 1, a magnetic flux in the same direction as the bias magnetic flux is generated from the coil 12 wound around the coil bobbin 10. It is assumed that the coil 13 wound around the coil bobbin 11 generates a magnetic flux in the direction opposite to the bias magnetic flux. The inductance of the coil decreases as the magnetic flux increases. The magnetic flux generated from the coil 12 increases because it is in the same direction as the bias magnetic flux, and the magnetic flux generated from the coil 13 decreases because it is in the opposite direction to the bias magnetic flux. Therefore, at this time, the inductance of the coil 12 decreases, the inductance of the coil 13 increases, and most of the current from the terminal 18 flows to the terminal 19 via the coils 12 and 14.

On the contrary, when a current is passed from the terminal 19 to the terminal 18, a magnetic flux in the direction opposite to the bias magnetic flux is generated from the coil 12 wound around the coil bobbin 10, and the coil 13 wound around the coil bobbin 11 is generated. A magnetic flux in the same direction as the bias magnetic flux is generated from the coil 13. Therefore,
The inductance of the coil 12 increases, the inductance of the coil 13 decreases, and most of the current from the terminal 19 flows to the terminal 18 via the coils 15 and 13.

Therefore, when the horizontal sawtooth wave current shown in FIG. 4 is passed between the terminals 18 and 19, the direction of the sawtooth wave current is
8 flows toward the terminal 19 from the terminal 23 of the coil 14 toward the terminal 24, the correction current shown in FIG. 5A flows through the coil 14, and on the contrary, a sawtooth current flows from the terminal 19 to the terminal 18. Coil 1 while flowing toward
The correction current shown in FIG. 5B flows from the terminal 25 of FIG. Convergence yokes 21 and 22
The correction magnetic field generated by the currents flowing through the two coils 14 and 15 wound around the coil is equal to the correction magnetic field generated by the current (FIG. 6) obtained by combining the currents flowing through the coils 14 and 15.

As can be seen from FIG. 6, the combined current of the correction current flowing through the coil 14 and the correction current flowing through the coil 15 is similar to the parabolic current. Therefore, when a horizontal sawtooth wave current is passed through the terminals 18 and 19, a correction magnetic field equivalent to that when a horizontal parabola current is passed through the convergence correction coil is generated, which allows convergence correction.

There is a section in which the deflection current decreases in the section indicated by T ₁ , T ₂ , and T ₃ , but this section does not cause any problem because it is a retrace section.

In this embodiment, the vertical convergence of the screen is corrected by using the deflection magnetic field as a barrel magnetic field.

This convergence correction device is mounted on a color cathode ray tube as shown in FIG.

FIG. 7 shows the entire deflection device of a color cathode ray tube to which the present invention can be applied. 31 in FIG.
Is a front cover of the separator, 32 is a rear cover of the separator, 33 is a core, and 34 is a mounting portion of a 2-pole, 4-pole or 6-pole magnet. Magnet mounting portion 34 and rear cover 32
Convergence yokes 21 and 22 are attached between and. As shown in FIG. 1, between the front cover 31 and the rear cover 32, the coil bobbin 10 around which the core 1, the magnets 7 and 8, and the coil 12 are wound, and the coil bobbin 11 around which the coil 13 is wound are provided. The configured convergence correction device 35 is fixed via a holder 36. A terminal plate for connecting a coil such as a vertical deflection coil is provided on one surface of the holder 36, and the convergence correction device 35 is attached to the other surface. The magnetic field of the convergence correction device 35 is arranged so as to be orthogonal to the vertical deflection magnetic field of the color cathode ray tube so that the correction magnetic field is not affected by the vertical deflection magnetic field.

[Outline of Invention]

According to the present invention, the correction current is caused to flow in the two coils, which generate the deflection magnetic fields opposite to each other in the direction of the sawtooth current wound around the convergence yoke, according to the direction of the sawtooth current. A correction magnetic field equivalent to that when a parabola current is passed through the convergence correction coil is obtained. As a result, the convergence correction can be performed with the deflection magnetic field kept uniform. As described above, the current for convergence correction can be formed without using a complicated external circuit, so that the convergence correction can be performed inexpensively without degrading the focus characteristics.

[Brief description of drawings]

FIG. 1 is a plan view of an embodiment of the present invention, FIG. 2 is a connection diagram of the embodiment of the present invention, and FIG. 3 is a sectional view used for explaining a convergence correction coil in the embodiment of the present invention. , FIG. 4 to FIG. 6 are waveform diagrams used for explaining one embodiment of the present invention, and FIG. 7 is a perspective view showing a mounting state of one embodiment of the present invention. Description of main symbols in the drawings 1: Core, 12, 13: Coil, 14, 15: Convergence correction coil, 18, 19: Terminal, 21, 22: Convergent yoke, 23, 24, 25, 26: Convergence Terminal derived from the correction coil.

Claims (1)

[Claims] 1. A core to which a bias magnetic field is applied, the first and second coils are wound so that the bias magnetic fields for the first and second coils are in opposite directions, and the convergence yoke has a third coil and a third coil. The fourth coil is wound and the first coil and the third coil are arranged so that the correction magnetic fields generated by the third coil and the fourth coil by the currents in the same direction are in opposite directions. A coil, the second coil and the fourth coil are connected in series,
A convergence correction device configured to connect a series connection of the first and third coils and a series connection of the second and fourth coils in parallel to supply a horizontal sawtooth current.