JP2001093443A - Deflection yoke and color cathode-ray tube receiver using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an over correction for a corner vertical miss-convergence when rising an amount of correction for a middle vertical miss-convergence, because the amount of correction for the middle vertical miss-convergence is almost half of that of the corner, in a convergence correction equipment which is modulated by vertical deflecting current. SOLUTION: In a deflection yoke equipped with a convergence correction equipment using a reactor 21 which can be saturated and in a color cathode-ray tube receiver using the deflection yoke, a middle vertical correction circuit 22 with a pair of diodes D1 and D2 which have opposite polarities and are connected in parallel with each other is connected with both ends of a center coil L15 of the reactor 21 which can be saturated. An amount of correction for a middle vertical miss-convergence can be increased owing to the diodes D1 and D2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deflection yoke equipped with a convergence correction device for correcting misconvergence of a color cathode ray tube (CRT) used in a television receiver or a display monitor, and a color using the deflection yoke. The present invention relates to a cathode ray tube receiver.

[0002]

2. Description of the Related Art In a color cathode ray tube, a color image is assembled on a screen by deflecting the traveling directions of three electron beams emitted from an electron gun up, down, left, and right. For deflection of the electron beam, a deflection yoke having a horizontal deflection coil and a vertical deflection coil is used.

[0003] The deflection yoke is mounted on a portion called a cone from the neck of the cathode ray tube to the funnel. In this deflection yoke, a deflection magnetic field is formed by flowing a horizontal deflection current to a horizontal deflection coil and a vertical deflection current to a vertical deflection coil on the trajectory of three electron beams emitted from the electron gun. The electron beam is deflected up, down, left, and right by the deflection magnetic field.

In a color cathode ray tube, R
The three electron beams corresponding to the colors (red), G (green), and B (blue) are concentrated on one point of a color selection electrode such as an aperture grill or a shadow mask (this is called convergence). A desired color image is reproduced on the screen. At this time, if so-called misconvergence occurs in which the three electron beams do not concentrate on one point of the color selection electrode, this causes color shift and color unevenness on the screen.

[0005] The form of the misconvergence is roughly classified into misconvergence occurring in the vertical direction (vertical direction) of the screen and misconvergence occurring in the horizontal direction (horizontal direction) of the screen. In addition, misconvergence that occurs in the vertical direction of the screen includes the center of the screen (X
Axis), there is a misconvergence that occurs in the middle part of the upper screen and the lower screen, and a misconvergence that occurs in the corner of the screen. It is called. The same can be said for misconvergence occurring in the horizontal direction of the screen.

Conventionally, a convergence correction device using a saturable reactor has been used for correcting vertical misconvergence. FIG. 10 shows a circuit configuration of the convergence correction device according to the conventional example.

In FIG. 10, a saturable reactor 100
Are the coil L101, the coil L102, and the coil L1.
03 and a coil L104 are wound in pairs, each coil pair is connected in series to a pair of horizontal deflection coils LH101 and LH102, and a center coil L105 is connected in series to a vertical deflection coil (not shown). It has a connected configuration. The modulation is performed by supplying a sawtooth vertical deflection current to the center coil L105.

[0008]

By the way, in a cathode ray tube (CRT) for a wide screen and a plane and a wide screen, the intermediate vertical misconvergence tends to increase as compared with a conventional cathode ray tube. However, in a conventional convergence correction device using a saturable reactor, modulation is performed using a vertical deflection current, and since the vertical deflection current is a sawtooth wave,
Since the amplitude of the vertical deflection current in the middle portion is half that of the corner portion, the correction amount for the middle vertical misconvergence is about half that of the corner portion. Therefore, if an attempt is made to increase the correction amount for the intermediate vertical misconvergence, overcorrection will be performed for the corner vertical misconvergence.

For this reason, in the conventional convergence correction device, the core diameter of the center coil L105 for vertical deflection current modulation in the saturable reactor 100, that is, the core diameter of the drum type core made of ferrite or the like that winds the coil L105 is determined. By reducing the thickness, the saturable reactor 100 is easily saturated, and the characteristic of saturation with respect to a change in the vertical deflection current is changed.

That is, when the amount of the vertical deflection current is large, the saturation of the saturable reactor 100 starts, and the increase in the correction amount for the corner vertical misconvergence is reduced. However, there is a limit in mass-producing a coil having a small core diameter, and fine adjustment is difficult. Therefore, the effect of reducing the core diameter of the center coil L105 is also limited.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a convergence correction device capable of reliably correcting an intermediate vertical misconvergence while suppressing the influence on other convergence characteristics. An object of the present invention is to provide a mounted deflection yoke and a color cathode ray tube receiver using the same.

[0012]

SUMMARY OF THE INVENTION A deflection yoke according to the present invention comprises two pairs of coils connected in series to a pair of horizontal deflection coils, and a vertical deflection coil located between the two pairs of coils. Equipped with a saturable reactor having a saturable reactor having a center coil connected in series to the coil, and a convergence correction device including a pair of diodes connected in parallel with opposite polarities between both ends of the center coil. The configuration is as follows. This deflection yoke is used for a color cathode ray tube receiver.

In the deflection yoke and the color cathode ray tube receiver using the same, when a pair of diodes are connected in parallel with opposite polarities to both ends of the center coil, a part of the vertical deflection current is corrected. When the current flows through the circuit and the amount of current increases, the diode corresponding to the direction of the current becomes conductive. As a result, the vertical modulation current supplied to the saturable reactor flows linearly with respect to the vertical deflection until the diode conducts, and then decreases by the amount of the vertical deflection current flowing to the correction circuit after the diode conducts. . As a result, the difference between the vertical misconvergence of the screen corner and the vertical misconvergence caused by the saturable reactor becomes smaller, and as a result, the correction amount of the middle part increases.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a schematic perspective view showing an overall image of a color cathode ray tube to which the present invention is applied.

In FIG. 1, a panel 12 having an inner surface provided with a fluorescent screen is attached to an opening of a picture tube valve 11,
An electron gun 13 for emitting an electron beam is sealed in the rear end of the picture tube valve 11. A cone-shaped deflection yoke 14 for deflecting the electron beam emitted from the electron gun 13 is attached to the neck of the picture tube valve 11.

FIG. 2 is a side view including a partially broken cross section of the deflection yoke 14 according to the present invention. 2, the deflection yoke 14 includes saddle (saddle) type horizontal deflection coils 15, saddle type vertical deflection coils 16, and coil bobbins 1.
7, parts such as a core 18, a ring magnet 19 and the like are provided.

The horizontal deflection coil 15 and the vertical deflection coil 16 deflect the electron beam emitted from the electron gun 13 in the horizontal direction (horizontal direction) and the vertical direction (vertical direction) of the screen. These deflection coils 15 and 16 are mounted on a coil bobbin 17 having a cone shape. Specifically, the horizontal deflection coil 15 is mounted on the inner peripheral side of the coil bobbin 17, and the vertical deflection coil 16 is mounted on the outer peripheral side of the coil bobbin 17.

The core 18 is made of ferrite, and is mounted so as to cover the deflection coils 15 and 16 in order to further improve the efficiency of the magnetic field generated from the deflection coils 15 and 16. The ring magnet 19 is provided on the neck side of the deflection yoke 14 to correct an assembly error of the electron gun 13.

FIG. 3 is a circuit diagram showing a configuration example of the convergence correction device mounted on the deflection yoke 14. As shown in FIG.

In FIG. 3, a saturable reactor 21 has a coil L11 and a coil L12, a coil L13 and a coil L14 wound in pairs, and a pair of horizontal deflection coils LH1.
1 and LH12 for each coil pair (L11, LH
12 and L13, L14) are connected in series. Note that the pair of horizontal deflection coils LH11 and LH12 correspond to the horizontal deflection coil 15 in FIG. 2, and are respectively mounted on the upper and lower sides of the X axis when viewed from the panel side.

Two coil pairs (L11, L12 and L1
3, L14) are supplied with a sawtooth horizontal deflection current through horizontal deflection coils LH11, L12. A center coil L15 located between these coil pairs is connected in series to a vertical deflection coil (not shown). And this center coil L1
5, a sawtooth vertical deflection current is supplied through a vertical deflection coil.

An intermediate vertical correction circuit 22 is connected between both ends of the center coil L15. The intermediate vertical correction circuit 22 has a pair of diodes D1 and D2 connected in parallel with opposite polarities. The intermediate vertical correction circuit 22 further includes a resistance element R0 connected in parallel to the pair of diodes D1 and D2, and a pair of diodes D1 and D2.
And an inductance element L0 connected in series.

Here, a specific structure of the saturable reactor 21 will be described. FIG. 4 is a schematic configuration diagram illustrating an example of the saturable reactor 21. The arrows in the figure indicate the directions of the magnetic fields generated according to the directions of the currents flowing through the coils L11 to L15. However, only an example is shown here.

In FIG. 4, coils L11 and L12 are wound around a drum core 31 in pairs and electrically connected in series with each other. These coils L11, L12
When the horizontal deflection current flows, both coils L11, L1
2 is wound in a winding direction in which a reverse magnetic field is generated.

The coils L13 and L14 are also of the drum type core 32.
And electrically connected in series to each other. These coils L13 and L14 are wound in a winding direction in which magnetic fields in opposite directions are generated in both coils L13 and L14 when a horizontal deflection current flows. In this example, the directions of the magnetic fields generated in the coils L12 and L13 are set to be the same so that the directions of the magnetic fields generated in the coils L11 and L13 are the same.

On the other hand, the center coil L15 is wound around a drum core 33 interposed between the drum cores 31 and 32. In addition, outside the drum cores 31 and 32,
Permanent magnets 34, 35 are arranged close to the drum cores 31, 32, for example, with the N pole inside. These permanent magnets 34 and 35 magnetically bias the coil pairs (L11, L12 and L13, L14) to
These coils L11 to L14 are magnetically saturated. Thereby, each inductance of the coils L11 to L14 is reduced.

Next, the operation of the saturable reactor 21 having the above configuration will be described. First, when a sawtooth vertical deflection current is supplied to the center coil L15 through a vertical deflection coil (not shown), a magnetic field is generated in the center coil L15. This magnetic field weakens the magnetic saturation of the coils L11 to L14 due to the bias magnetic fields of the permanent magnets 34 and 35, and increases the inductance of the coils L11 to L14.

Here, as shown in FIG.
The upper and lower left and right regions are divided into the first quadrant, the upper left region as the second quadrant, the lower left region as the third quadrant, the lower right region as the fourth quadrant, and the saturable reactor Consider a case in which a vertical deflection current and a horizontal deflection current are passed through 21. The vertical deflection current waveform is shown on the left side of the screen, and the horizontal deflection current waveform is shown on the lower side of the screen.

FIG. 6 shows a saturable reactor 2 in each quadrant when a vertical deflection current and a horizontal deflection current are applied.
1 is shown. In the figure, the parts shown in black are:
This indicates that the magnetic field is in a magnetic saturation state.

First, in the first quadrant, since the vertical deflection current has a negative polarity, the magnetic saturation of the coils L11 and L12 is weakened. At this time, since the horizontal deflection current is positive, the direction of the magnetic field is the same as that of the center coil 15 in the coil L1.
1 reduces the magnetic saturation, and thus the inductance of the coil L11 increases. Also in the second quadrant, since the vertical deflection current is negative, the magnetic saturation of the coils L11 and L12 is weakened. At this time, since the horizontal deflection current has a negative polarity, the magnetic saturation of the coil L12 having the same direction of the magnetic field as the center coil 15 is weakened.
Increases in inductance.

In the third quadrant, since the vertical deflection current has a positive polarity, the magnetic saturation of the coils L13 and L14 weakens. At this time, since the horizontal deflection current is negative,
The magnetic saturation of the coil L13 having the same direction of the magnetic field as that of the center coil 15 is weakened, and thus the inductance of the coil L13 is increased. Also in the second quadrant, since the vertical deflection current has a positive polarity, the magnetic saturation of the coils L13 and L14 is weakened. At this time, since the horizontal deflection current has a positive polarity, the coil L having the same direction of the magnetic field as the center coil 15 has.
14, the magnetic saturation of the coil L14 decreases, and thus the inductance of the coil L14 increases.

As described above, in the saturable reactor 21, the vertical deflection current flows through the center coil L15, and the magnetic field generated in the coil L15 accordingly causes the coils L11 to L11 due to the bias magnetic fields of the permanent magnets 34 and 35.
14, the magnetic saturation of the coils L11 to L14 is increased. Due to this change in inductance, vertical misconvergence is corrected. Note that the change in the inductance is reversed between the upper and lower portions of the screen, and the vertical misconvergence is inverted between the upper and lower portions of the screen.

The above description is the basic principle of the convergence correction using the saturable reactor 21. FIG.
7 shows the amount of misconvergence correction of the side beam R with respect to the side beam B by the convergence correction device using the saturable reactor 21. In the conventional convergence correction device, as described above, since the vertical deflection current is a sawtooth wave, the amplitude of the vertical deflection current in the middle portion is half that of the corner portion, and therefore, the correction amount d1 of the middle vertical misconvergence is smaller than the corner portion. It is about half the correction amount d2 of the vertical misconvergence.

On the other hand, in the convergence correction device according to the present embodiment, the intermediate longitudinal portion having a pair of diodes D1 and D2 connected in parallel with opposite polarities between both ends of the center coil L15 of the saturable reactor 21. By adopting a configuration in which the correction circuit 22 is connected, the correction amount for the intermediate vertical misconvergence is increased. Hereinafter, the operation of the intermediate vertical correction circuit 22 will be described.

First, in the circuit diagram of FIG. 3, considering that the intermediate vertical correction circuit 22 is not connected, the vertical modulation current supplied to the saturable reactor 21 is the same as the vertical deflection current of the sawtooth wave. The current i in FIG.
_{Like vo} , it increases linearly with vertical deflection. In this case, the correction amount d1 of the intermediate vertical misconvergence is about half of the correction amount d2 of the corner vertical misconvergence (see FIG. 7).

On the other hand, when the intermediate vertical correction circuit 22 is connected, a part of the vertical deflection current flows to the correction circuit 22, and when the amount of the current increases, the diode D1 corresponding to the direction of the current flows. / D2 becomes conductive. As a result, the vertical modulation current supplied to the saturable reactor 21 is
Like the current _{iv1 in} FIG. 8, the current flows linearly with respect to the vertical deflection until the diode D1 / D2 becomes conductive, and decreases by the amount flowing to the intermediate vertical correction circuit 22 after the diode D1 / D2 becomes conductive. .

As described above, by connecting the intermediate vertical correction circuit 22 having the diodes D1 and D2 to both ends of the center coil L15, the correction amount d1 of the intermediate vertical misconvergence can be reduced as shown in FIG. This can be made substantially equal to the convergence correction amount d2. That is, the difference in vertical misconvergence between the screen corner portion and the middle portion due to the saturable reactor 21 is reduced, and as a result, the correction amount of the middle portion can be increased.

In the intermediate vertical correction circuit 22, the diode D is changed by changing the resistance value of the resistance element R0.
1, the operating voltage of D2 (the inflection point of the current _iv1 in FIG. 8)
Can be adjusted arbitrarily. Also, in the saturable reactor 21, a vertical deflection current flows through the coil (center coil L15). Therefore, if the intermediate vertical correction circuit 22 is composed of only the diodes D1 and D2 and the resistance element R0, the phase of the current flowing through the circuit 22 is reduced. Cause a gap. The inductance element L0 functions to adjust the phase of this current. However, the resistance element R0 and the inductance element L0 are not essential components.

[0039]

As described above, according to the present invention,
By connecting a correction circuit having a pair of diodes connected in parallel with opposite polarities between both ends of the center coil of the saturable reactor, it is possible to increase the correction amount for the intermediate vertical misconvergence. The intermediate vertical misconvergence can be reliably corrected while suppressing the influence on the convergence characteristics, particularly, the corner vertical convergence. Therefore, when applied to a large-screen flat-panel cathode ray tube, for example, where the intermediate vertical misconvergence tends to increase compared to the conventional cathode ray tube, even if the correction amount of the intermediate vertical misconvergence is increased, the corner vertical misconvergence can be increased. Is not overcorrected.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing an overall image of a color cathode ray tube to which the present invention is applied.

FIG. 2 is a side view including a partially broken surface of the deflection yoke according to the present invention.

FIG. 3 is a circuit diagram illustrating a configuration example of a convergence correction device.

FIG. 4 is a schematic configuration diagram illustrating an example of a saturable reactor.

FIG. 5 is a diagram showing a relationship between each screen of a first quadrant to a fourth quadrant obtained by dividing the X-axis and the Y-axis as boundaries, and a vertical deflection current waveform and a horizontal deflection current waveform.

FIG. 6 is a diagram showing a state of a saturable reactor in the first to fourth quadrants when a vertical deflection current and a horizontal deflection current are applied.

FIG. 7 is a diagram illustrating a correction amount of misconvergence of a side beam R with respect to a side beam B when an intermediate vertical correction circuit is not connected.

FIG. 8 is a characteristic diagram of a vertical modulation current with respect to vertical deflection, where _iv0 is a current when no intermediate vertical correction circuit is connected, i
_v1 indicates a current when the intermediate vertical correction circuit is connected.

FIG. 9 is a diagram illustrating a correction amount of misconvergence of a side beam R with respect to a side beam B when an intermediate vertical correction circuit is connected.

FIG. 10 is a circuit diagram showing a convergence correction device according to a conventional example.

[Explanation of symbols]

11 picture tube valve, 13 electron gun, 14 deflection yoke, 15, LH11, LH12 horizontal deflection coil, 16
... vertical deflection coil, 21 ... saturable reactor, 22 ... intermediate vertical correction circuit, 31-33 ... drum type core, 34, 35 ...
Permanent magnet, D1, D2: diode, L0: inductance element, L15: center coil, R0: resistance element

Claims (6)

[Claims] 1. Two sets of coil pairs connected in series to a pair of horizontal deflection coils, and a center coil located between the two sets of coil pairs and connected in series to a vertical deflection coil. A deflecting yoke comprising a saturable reactor having: a saturable reactor having a convergence correction device having a pair of diodes connected in parallel with opposite polarities between both ends of the center coil. 2. The deflection yoke according to claim 1, wherein the correction circuit has a resistance element connected in parallel to the pair of diodes. 3. The deflection yoke according to claim 1, wherein the correction circuit has an inductance element connected in series to the pair of diodes. 4. The correction circuit according to claim 1, wherein the correction circuit includes a resistance element connected in parallel to the pair of diodes and an inductance element connected in series to the pair of diodes. Deflection yoke. 5. Two coil pairs respectively connected in series to a pair of horizontal deflection coils, and a center coil located between these two pairs of coils and connected in series to a vertical deflection coil. And a deflection yoke equipped with a convergence correction device including a correction circuit having a pair of diodes connected in parallel with opposite polarities between both ends of the center coil. Color cathode ray tube receiver. 6. The correction circuit according to claim 5, wherein the correction circuit includes a resistance element connected in parallel to the pair of diodes and an inductance element connected in series to the pair of diodes. Color cathode ray tube receiver.