JPH08138574A - Deflection yoke device - Google Patents

Abstract

PURPOSE: To provide a low-cost deflection yoke device which has a relieved B'ing, high deflection sensitivity for electron beams, and small dispersion in the deflecting characteristics. CONSTITUTION: A deflection yoke device is equipped with a pair of vertical deflection coils 4A, 4B in a troidal shape, wherein shunt circuit 7A, 7B provided through diodes 6A, 6B as switching element and resistors 5A, 5B are connected parallel with the coils 4A, 4B. The diodes 6A, 6B work so that the shunt circuits 7A, 7B are turned on alternately when the upper part of the screen of a cathode- ray tube is scanned (when a positive voltage is impressed on the coils 4A, 4B) and when the lower part of the screen is scanned (when a negative voltage is impressed). Thereby the intensity of the magnetic field SB of the vertical deflecting coil 4B becomes smaller than that of the magnetic filed SA of the vertical deflecting coil 4A when the upper part is scanned-when the lower part is scanned, the intensity of SA becomes smaller than that of SB. Thus the balance of the intensity of SA and SB is corrected, and an excellent deflecting characteristic is generated with B'ing relieved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deflection yoke device mounted on a cathode ray tube such as a television receiver or a display device.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional deflection yoke device 12 mounted on a cathode ray tube of a television receiver or a display device. The deflection yoke device 12 includes a deflection coil bobbin 10 in the shape of a bosh, a pair of saddle-shaped horizontal deflection coils (not shown) that are formed along the inner peripheral surface of the deflection coil bobbin 10 and that face each other. The saddle-shaped vertical deflection coil is formed on the outer top side and the bottom side, and the correction coils 14A and 14B are provided on the top side and the bottom side of the deflection coil bobbin 10 on the neck side.

As shown in FIG. 6, the vertical deflection coil 3A on the top side, the vertical deflection coil 3B on the bottom side, the correction coil 14A on the top side and the correction coil 14B on the bottom side are connected in series. The correction coils 14A, the 14B series circuit of the corresponding diode D _1, D ₂ resistors R _1, R ₂ are connected in parallel.

As shown in FIG. 3, the deflection yoke device 12 emits an electron gun G _B which emits an electron beam of blue B, an electron gun G _G which emits an electron beam of green G, and an electron beam of red R. An electron gun G _R is attached to a cathode ray tube arranged inline from the left side to the right side, and a horizontal deflection magnetic field generated by the horizontal deflection coil and a vertical deflection coil 3
By the vertical deflection magnetic field generated from A, 3B, B,
The G and R electron beams are deflected and scanned on the image receiving surface (screen).

[0005]

By the way, three (B,
Wherever the G, R) electron beams are deflected on the image receiving surface, they should ideally be converged on the image receiving surface. However, in reality, it is difficult to control the deflection magnetic field so that the three electron beams are gathered into one at any deflection position on the image receiving surface. Particularly, it is generated from the vertical deflection coil 3A on the top side. Vertical deflection magnetic field V
And strength of _A, the collapse strength balance of the vertical deflection magnetic field V _B to be generated from the bottom side of the vertical deflection coil 3B,
Misconvergence (color shift) called Bing may occur in the Y axis direction of the image receiving surface as shown in FIG. 4A.

Therefore, in the conventional example, the vertical deflection magnetic field V is corrected by using the correction coils 14A and 14B to correct the Bing.
_The following measures are taken to correct the balance between the strengths of _A and V _B.

First, as shown in FIG. 3, a vertical symmetry axis that bisects the image receiving surface of the cathode ray tube into a top side (upper side) and a bottom side (lower side) is defined as an X axis. When deflecting three electron beams, the vertical deflection coil 3
For example, a positive current is applied to A and 3B with a current amount corresponding to the deflection position of the electron beam. In FIG. 6, it is assumed that the current + I ₁ is flowing. In the figure, when the positive current of this current + I ₁ flows, the diode D _{2 in the} opposite direction is turned off. Therefore, the current + I ₁ flows into the correction coil 14B without being shunted between the points α and β, Since the diode D _{1 in the} forward direction is turned on between the point β and the point γ, the current is divided into the current + I ₂ flowing through the correction coil 14A and the current + I ₃ flowing through the resistor R ₁ and the diode D ₁ .

As described above, the vertical deflection coils 3A, 3B
And a current flows through the correction coils 14A and 14B, the vertical deflection coils 3A and 3B generate vertical deflection magnetic fields V _A and V _B , and the correction coils 14A and 14B generate a correction magnetic field in a direction of canceling the vertical deflection magnetic field. . By the way, the strength of the correction magnetic field generated from the correction coil 14B is larger than the strength of the correction magnetic field generated from the correction coil 14A.

Therefore, the vertical deflection magnetic field V _B of the vertical deflection coil 3B is changed by the correction magnetic field.
More than the vertical deflection magnetic field V _{A of A} is canceled, the strength of V _B that gives a force to the B and R beams in a direction that deteriorates Bing as shown by the arrow in FIG.
As shown in FIG. 4B, the Bing at the top end on the image receiving surface can be locally mitigated.

Next, when deflecting the three electron beams to the bottom side from the X axis of the image receiving surface as shown in FIG. 3, the vertical deflection coils 3A and 3B have a polarity opposite to the current polarity at the time of deflection on the top side. Current is supplied with a current amount according to the deflection position of the electron beam.

At the time of deflection on the bottom side, as is clear from FIG. 6, the correction coil 14A is opposite to that at the time of deflection on the top side.
Of the vertical deflection magnetic field V _A of the vertical deflection coil 4A acting on the B and R beams in a direction that worsens the Bing on the bottom side, since the strength of the correction magnetic field of A becomes larger than the strength of the correction magnetic field of the correction coil 14B. Becomes smaller. Then, FIG. 4B
As shown in, the Bing at the bottom side lower end portion on the image receiving surface can be locally relaxed.

As described above, the correction coils 14A and 14B
The correction magnetic fields generated at the upper and lower ends of the image receiving surface correct the balance between the strengths of V _A and V _B , and locally relax the Bing at the upper and lower ends of the image receiving surface. You can

However, since the conventional Bing correction method uses the correction coils 14A and 14B only for correction, there is a problem that the number of parts of the deflection yoke device 12 increases and the manufacturing cost increases.

Further, when the correction coils 14A and 14B are manufactured, variations in processing accuracy occur, and further, the correction coils 14A and 14B are manufactured.
When B is incorporated in the deflection yoke device 12, variations such as positional deviations occur, and it is difficult to make the deflection characteristics of the electron beams in all the deflection yoke devices 12 the same.

Further, since the correction coils 14A and 14B are connected to the vertical deflection coils 3A and 3B, the correction coil 14A
A current loss occurs due to the impedance components of A and 14B,
There is a problem that the amount of current flowing through the vertical deflection coils 3A and 3B is reduced, and the deflection sensitivity of the electron beam is reduced. As a means for solving this problem, it is possible to flow a large current in consideration of the current loss,
There is a problem that the power supply circuit becomes large.

The present invention has been made in order to solve the above problem, and its purpose is to effectively correct Bing, to improve the deflection sensitivity of an electron beam, and to vary the deflection characteristics of the electron beam. It is to provide a small and inexpensive deflection yoke device.

[0017]

In order to achieve the above object, the present invention is constructed as follows. That is, the deflection yoke device of the first invention is a deflection yoke device provided with a pair of toroidal vertical deflection coils, wherein both vertical deflection coils are connected in series, and each vertical deflection coil has a switch. A shunt circuit in which an element and a resistance component are connected in series is connected in parallel, and the ON operation of each shunt circuit is alternately switched between the upper scanning and the lower scanning of the screen of the cathode ray tube to switch the Bing pattern. It is configured to correct misconvergence.

The deflection yoke device of the second invention is characterized in that the switch element of each shunt circuit in the deflection yoke device of the first invention is composed of a diode.

The deflection yoke device of the third invention is characterized in that a resistance component is connected in parallel to each vertical deflection coil in the deflection yoke device of the first invention or the second invention. There is.

[0020]

In the present invention having the above-described structure, when the screen of the cathode ray tube is scanned upward, a large amount of current flows in the vertical deflection coil on one side, for example, the lower side, so that the vertical deflection magnetic fields of the pair of vertical deflection coils are unbalanced. When the lower side scanning is performed, on the contrary, a large amount of current flows in the upper side vertical deflection coil on the other side, and an imbalance in the vertical deflection magnetic field of the pair of vertical deflection coils occurs, thereby correcting the misconvergence of the Bing pattern. In doing so, the lower shunt circuit is turned on during the upper scan, and the current in the lower vertical deflection coil is reduced. Further, during the lower scanning, the upper shunt circuit is turned on to reduce the current of the upper vertical deflection coil.

As described above, the balance of the vertical deflection magnetic field of the vertical deflection coil is corrected, and the misconvergence of the Bing pattern is effectively corrected.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. The deflection yoke device of this embodiment has a deflection coil bobbin 10 and a horizontal deflection coil (not shown) as shown in FIG. 5, which is similar to the conventional example. On the outer top and bottom sides of the deflection coil bobbin 10, a pair of toroidal vertical deflection coils having the functions of the correction coils 14A and 14B of the conventional example, and a shunt circuit connected in parallel to each vertical deflection coil are provided. It is configured to have.

As shown in FIG. 1, the vertical deflection coil 4A on the top side and the vertical deflection coil 4B on the bottom side are connected in series. Corresponding shunt circuits 7A and 7B are connected in parallel to the vertical deflection coils 4A and 4B, respectively. In the shunt circuits 7A and 7B, diodes 6A and 6B which are switching elements and resistors 5A and 5B are connected. Is connected in series.

In the figure, the diode 6A is switched off when a positive current, for example + I _o, is applied to the circuit 9 shown in FIG. 1, and on the contrary, a negative current, for example-, is applied to the circuit 9. When I _o is energized, the diode 6A is switched on. Further, the diode 6B performs a switching operation opposite to the switching operation (ON / OFF) of the diode 6A, and is turned on when a positive current is applied to the circuit 9, and a negative current is applied to the circuit 9. When turned off, the switch is turned off.

The shunt circuits 7A and 7B are composed of the diode 6 described above.
When A and 6B are switched on, a current corresponding to the resistors 5A and 5B is applied. For example, when a positive current + I _o is applied to the circuit 9, the diode 6A is switched off and the diode 6B is switched on, so that the shunt circuit 7A is not energized and + I is applied to the vertical deflection coil 4A. _o flows. Further, the shunt circuit 7B is energized, and the current shunted from + I _o to the shunt circuit 7B + I _n.
And the remaining current + I _{m obtained} by _dividing + I _o to + I _n flows through the vertical deflection coil 4B.

On the contrary, when a negative current -I _o is applied to the circuit 9, the diode 6A is switched on and the diode 6B is switched off, so that the shunt circuit 7A is energized and the shunt circuit 7A is turned on. current flows -I _q diverted from -I _o to, -I _o to the vertical deflection coil 4A
To -I _q , the remaining current -I _p flows. Further, the shunt circuit 7B is not energized, and -I _o flows through the vertical deflection coil 4B.

In the deflection yoke device having the above structure, as shown in FIG.
The correction operation of the Bing pattern as shown in (a) of will be described. This kind of Bing pattern is on the top side (upper side) from the X axis of the image receiving surface (screen of the cathode ray tube) shown in FIG.
At the time of scanning the electron beam at (in the upper scanning (for example, when a positive current is applied to the circuit 9 in FIG. 1)), a large amount of current flows in the vertical deflection coil 4B on the bottom side, so that the vertical deflection coil 4A Of the vertical deflection magnetic field S _A and the vertical deflection magnetic field S _B of the vertical deflection coil 4B are unbalanced, and a negative current having a polarity opposite to that of the upper scanning is applied to the circuit 9. This occurs because a large amount of current flows through the vertical deflection coil 4A on the top side when the electric currents S _A and S _B are unbalanced.

As shown in FIG. 1, by providing the diodes 6A and 6B, the shunt circuit 7B is energized and the current flowing through the vertical deflection coil 4B is shunted during the upper scanning.
The current flowing through the vertical deflection coil 4A is reduced by the amount of the current divided by the current dividing circuit 7A during the lower scanning, and the current flowing through the vertical deflection coil 4A is reduced by the amount of the current divided by the current dividing circuit 7A.
By correcting the imbalance between the strengths of S _A and S _B reaching the G and R electron beams, the Bing in the central area of the image receiving surface is effectively alleviated as shown in FIG. 2B.

Further, when a pattern opposite to the Bing shown in FIG. 2A appears, the diodes 6A and 6B are provided in the direction opposite to that shown in FIG. Is possible. The resistors 5A and 5B
The resistance value of is set according to the degree of Bing, for example, it is set to be small when Bing is large.

According to this embodiment, the shunt circuits 7A and 7B are connected in parallel to the vertical deflection coils 4A and 4B without providing the correction coil as in the conventional example. Since 14B is unnecessary, the manufacturing cost can be reduced accordingly, and an inexpensive deflection yoke device can be provided.

Further, as described above, since the correction coils 14A and 14B dedicated to correction as in the conventional example are not provided,
In the vertical deflection coils 4A and 4B, current reduction corresponding to the current loss of the correction coil is eliminated, and Bing can be corrected without deteriorating the deflection sensitivity of the electron beam.

Further, in the conventional example, there was a problem of variations in the deflection characteristics of the electron beam due to the positional deviation when the correction coil was incorporated. However, in the present embodiment, the correction coil is not required, so The problem of variation in the deflection characteristics due to the displacement of the correction coil does not occur.

The present invention is not limited to the above-mentioned embodiments, and various embodiments can be adopted. For example, in the above embodiment, the diodes 6A and 6B are used as the switching elements.
However, a switch element using a transistor (including FET) or the like may be used. In this case, a switching control circuit for switching elements is provided. However, when the diodes 6A and 6B are used, the switch changeover control circuit becomes unnecessary and a more inexpensive deflection yoke device can be provided.

Further, the vertical deflection coils 4A and 4B may be connected in parallel with resistors as shown by the dotted lines in FIG. Such a resistor is a vertical deflection coil 4A,
The deflection sensitivity can be adjusted by changing the amount of current flowing in 4B and thus changing the amount of current.

[0035]

According to the present invention, the ON operation of the pair of shunt circuits is alternately switched between the upper scanning and the lower scanning of the screen of the cathode ray tube to change the amount of current flowing in each vertical deflection coil. Since the balance in the strength of the vertical deflection magnetic field of the pair of vertical deflection coils is corrected and the misconvergence of the Bing pattern is corrected, it is not necessary to provide a correction coil dedicated to the correction as in the conventional case, and the correction coil for that is eliminated. No current loss occurs. Therefore, the apparatus of the present invention can correct the misconvergence of the Bing pattern without deteriorating the deflection sensitivity.

Further, as described above, since the correction coil is unnecessary, the manufacturing cost can be reduced by that amount, and an inexpensive deflection yoke device can be provided.

Further, in the conventional example, the canceling magnetic field of the correction coil fluctuates due to the positional deviation when the correction coil is incorporated, and the deflection characteristics fluctuate. However, in the deflection yoke device of the present invention, the correction coil is unnecessary. Therefore, there is no variation in the deflection characteristics due to the positional deviation.

Further, in the configuration in which the switch element is a diode, it is possible to switch the on / off operation of each shunt circuit between the upper scanning and the lower scanning without providing a large switch control circuit. Thus, it is possible to provide a cheaper deflection yoke device.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of a main part of an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing the misconvergence of the Bing pattern and the misconvergence of the corrected Bing pattern when the deflection yoke device of the present embodiment is used.

FIG. 3 is an explanatory diagram showing a relationship between electron guns arranged in-line and an image receiving surface of a cathode ray tube.

FIG. 4 is an explanatory diagram showing the misconvergence of the Bing pattern and the misconvergence of the Bing pattern corrected in the conventional example.

FIG. 5 is an explanatory diagram showing a relationship between a correction coil and a deflection coil bobbin.

FIG. 6 is a circuit diagram illustrating a conventional example.

[Explanation of symbols]

 4A, 4B vertical deflection coil 6A, 6B diode 7A, 7B shunt circuit

Claims (3)

[Claims] 1. A deflection yoke device provided with a pair of toroidal vertical deflection coils, wherein both vertical deflection coils are connected in series, and each vertical deflection coil has a switch element and a resistance component in series. The connected shunt circuits are connected in parallel, and the ON operation of each shunt circuit is alternately switched between the upper scanning and the lower scanning of the screen of the cathode ray tube to correct the misconvergence of the Bing pattern. Deflection yoke device. 2. The deflection yoke device according to claim 1, wherein the switch element of each shunt circuit is formed of a diode. 3. A deflection yoke device according to claim 1, wherein a resistance component is connected in parallel to each vertical deflection coil.