JPH08162045A - Deflection yoke device - Google Patents

Abstract

PURPOSE: To reduce the convergence error. CONSTITUTION: A horizontal deflection coil 1 is divided into main deflection coils 1aa, 1ba and sub-deflection coils 1ab, 1bb, and a permanent magnet 5 and an auxiliary circuit having auxiliary coils 4a, 4b arranged in a magnetic circuit constituted so that its magnetic path is a closed circuit are provided. The auxiliary coils 4a, 4b are connected in series to the sub-deflection coils 1ab, 1bb.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube used for a television receiver or the like, and more particularly to a deflection yoke which is mainly used for high-definition and screen aspect ratio of 9:16.

[0002]

2. Description of the Related Art FIG. 9 is a side view of a conventional deflection yoke device. Here, 1 is a horizontal deflection coil, 2 is a vertical deflection coil, and 3 is a core. As shown in this figure, the horizontal deflection coil 1 is composed of two coils arranged vertically.

In order to explain the magnetic field generated by the horizontal deflection coil constructed as described above, a typical electromagnetic deflection schematic diagram will be used. FIG. 10 is a schematic diagram of electromagnetic deflection using the horizontal deflection coil of FIG. In this figure, a magnetic field is made uniform by a deflection coil of length L from the back of the paper toward the front for L intervals, and is zero outside it, and electrons are incident at a velocity v at a right angle to the magnetic field from the direction of the arrow. In general, the tube surface of the cathode ray tube expresses naturalness, and therefore, a diagonal side view of the 29-inch cathode ray tube is shown in FIG. 11. Compared to an arc centered on the deflection center (which will be described later), it is almost a plane, and in such a case, in this electromagnetic deflection schematic diagram, it is regarded as a completely flattened surface.
As shown in FIG. 10, the tube surface is represented by a straight line.

In the electromagnetic deflection schematic diagram of FIG. 10, an electron beam is emitted from an electron gun, receives deflection energy in a deflection region, and is deflected in an arc shape. However, when the electron beam exits the deflection area, it travels straight at the deflection angle at the exit point. In the case of this example, at the deflection angle θ, the vehicle continues straight ahead and collides with the tube surface to emit light from the phosphor, so that an image can be obtained on the cathode ray tube.

Further, the deflection angle θ is extended to the electron gun side,
The intersection with the undeflected electron beam is the deflection center.
Then, with this deflection center as the base point, it is assumed that the deflection is performed at the deflection angle θ, and the line is displayed. The following is a description of such display method.

In general, the cathode ray tube has a color, so that
As shown in, the cathode ray tube obtains an image by three electron beams emitted from the deflection centers of the electron guns in which three electron guns are arranged in a line. At the time of deflection, the electron beams at both ends, that is, the blue electron beam and the red electron beam, are inclined at an angle θ so that their spots coincide with the center of the screen.

[0007]

In the cathode ray tube having such a structure, when deflected by a uniform magnetic field, for example, the electron beams on both sides are deflected at the same angle with the deflection center as the base point as described above. Therefore, the point where the electron beams on both sides intersect, that is, the point of convergence (ignition surface) is separated from the tube surface in the peripheral part of the screen,
The position is closer to the electron gun than the center of the screen, and a convergence error (under-convergence) as shown in FIG. 12 occurs.

Therefore, in order to transfer this to the shadow mask, the horizontal deflection magnetic field is made into a pincushion,
It is necessary to increase the sensitivity of the electron beam located on the deflection side and weaken the sensitivity of the electron beam located on the opposite side of the deflection side, but if the tube surface is made in an arc shape, the amount of the pincushion magnetic field is also increased. A small value is required.

However, when the tube surface is flattened, the ignition surface in the peripheral portion of the screen becomes closer to the electron gun, and the pincushion amount also increases. Further, when deflected by such a strong pincushion magnetic field, the tube surface is flattened even if it converges in the peripheral portion of the screen, so that in the central part of the screen, rather, due to the strong pinch magnetic field, As shown in, the convergence goes too far and the convergence does not occur at the center of the screen (this is called overconvergence).

In other words, if the tube surface is made flat, the horizontal deflection magnetic field cannot be dealt with by a single performance. Therefore, a strong pincushion magnetic field is required to deflect the peripheral portion of the screen, and a uniform deflection is required to deflect the central portion of the screen. A close pincushion field is needed.

It is obvious that this phenomenon is more remarkable when the screen is horizontally long. The object of the present invention is to solve the conventional problems as described above, and to deflect by the deflection magnetic field required by the central portion and the peripheral portion of the screen, no matter how flat the tube surface or the screen becomes horizontally long. By doing so, the convergence error appearing on the screen is eliminated.

[0012]

In order to achieve the above object, the present invention has a horizontal deflection coil divided into a main deflection winding coil and a sub-deflection winding coil, and a permanent magnet and its magnetic path are formed as a closed circuit. An auxiliary circuit having an auxiliary coil is provided in the magnetic circuit, and the auxiliary coil and the sub-deflection winding coil are connected in series.

The permanent magnet used in the auxiliary circuit has a disk shape having N and S poles diagonally, and has a structure of rotating around a center point. By rotating it, a magnetic field flowing in the magnetic circuit is generated. The magnetic field strength changes depending on the direction of rotation and the rotation angle, so that the current flowing through the auxiliary coil is controlled.

[0014]

According to the present invention, in the above-mentioned structure, the main deflection winding coil of the horizontal deflection coil is set so as to obtain a pincushion magnetic field which is almost uniform, and the sub deflection winding coil is set so as to obtain a strong pincushion magnetic field. Since the deflection current flowing in the coil is proportional to the deflection amount, the deflection amount is small, that is, the electron beam is deflected in the center of the screen by the deflection magnetic field created by the main deflection winding coil, which causes a convergence error on the screen. When the deflection current reaches a certain value, that is, when the electron beam is deflected in the peripheral area of the screen, the deflection current starts to flow in the auxiliary coil due to the magnetic saturation effect. A deflection current also flows through the sub-deflection winding coil connected to the main deflection winding coil, which contributes to the deflection of the electron beam. Become combined magnetic field of the Le, now magnetic field required to obtain, so obtaining a deflection magnetic field to eliminate the convergence error in this range.

Further, in order to reduce variations in manufacturing the cathode ray tube and the deflection yoke device, the magnet capable of changing the magnetic field generated by rotating the auxiliary circuit so that the amount of magnetic saturation can be adjusted. It is arranged.

[0016]

【Example】

(Embodiment 1) Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. The same parts as those described in the above-mentioned conventional example are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 1 is a front view of a horizontal deflection coil of the present invention and a circuit diagram thereof. As is apparent from FIG. 1A, the horizontal deflection coil 1 includes the main deflection winding coils 1aa and 1ba.
And sub-deflection winding coils 1ab and 1bb. The deflection magnetic field generated by the main deflection winding coils 1aa and 1ba forms a pincushion magnetic field close to the uniform magnetic field, and the deflection magnetic field generated by the sub-deflection winding coils 1ab and 1bb forms a strong pincushion magnetic field. ing.

A circuit diagram of this is shown in FIG. 1 (b). That is, the horizontal deflection coil 1 is a set of upper and lower coils, but the horizontal deflection coils 1 and 2 are the main deflection winding coils 1aa and 1ba and the sub-deflection winding coil 1.
It is divided into ab and 1bb. The upper and lower sub-deflection winding coils 1ab and 1bb are connected in series to the auxiliary coils 4a and 4b. Further, the auxiliary circuit is composed of the permanent magnet 5 and the auxiliary coils 4a and 4b, is a magnetically closed circuit, and is a circuit utilizing magnetic saturation characteristics.

The auxiliary circuit will be described with reference to FIG. In FIG. 2A, 6 is a magnetic core of the auxiliary coil. The magnetic core 6 has a form sandwiching the permanent magnet 5 and is a closed circuit in terms of magnetic circuit. Further, although the auxiliary coils 4a and 4b are formed by winding two electric wires, which are so-called bihilar windings, at the same time, the magnetic fluxes generated from the coils are set in different directions.
That is, in FIG. 2B, the magnetic flux φM generated by the permanent magnet 5, the magnetic flux φa generated by the auxiliary coil 4a, and the auxiliary coil 4b.
The magnetic flux φb is due to φM and φa when the deflection current is positive.
In the same direction, φM and φb in different directions, and when the deflection current is negative, φM and φb are in the same direction, and φM and φb are in the same direction.
a is set to occur in different directions.

The horizontal deflection coil and the auxiliary circuit configured as described above will be described below. FIG. 3 is a diagram for explaining a cathode ray tube screen and a deflection angle when scanning the same. Reference numeral 7 is a deflection center, 8 is a cathode ray tube screen, and the deflection direction is positive and the deflection current is deflected to the right side of the screen. I shall. That is, the case where φM and φa are in the same direction will be described, and the case where the deflection direction is negative and the deflection current is deflected to the left side of the screen is completely opposite, and description thereof will be omitted. At this time, the deflection amount D1 is obtained at the deflection angle θ1, and the deflection amount D2 is obtained at the deflection angle θ2. Further, in order to obtain the deflection angle θ1, a current i1 is applied to the horizontal deflection coil 1, and in order to obtain the deflection angle θ2, the current i1 is applied to the horizontal deflection coil.
Suppose you have to throw 2.

Generally, in the auxiliary circuit utilizing such magnetic saturation characteristics, the current flowing through the auxiliary coil has the magnetic saturation characteristics (inductance-current characteristics) as shown in FIG. That is, the inductance of the auxiliary coil is almost constant within a certain range of the deflection current value, but more than that (in this case, if that point is k point, it is 1A).
When the deflection current flows, the inductance sharply decreases.

In the case of this embodiment, this point k is defined as the deflection current i1. The point deflected by the deflection current i1 is D1. That is, the current required to obtain the deflection angle θ1 is i1. Up to the deflection amount D1, no current flows through the auxiliary coils 4a, 4b having the magnetic saturation characteristic, and therefore no current flows through the sub-deflection winding coils 1ab, 1bb, which are generated by the sub-deflection winding coils 1ab, 1bb. There is no magnetic field. However, when the deflection current exceeds i1 (the deflection amount exceeds D1), the inductance of the auxiliary coils 4a and 4b having the magnetic saturation characteristic gradually decreases, and the auxiliary coil 4 is reduced by the reduced inductance.
An electric current flows through a and 4b, so that the sub-deflection winding coil 1
Current also flows through ab and 1bb, and the sub-deflection winding coil 1a
A magnetic field is generated by b and 1bb.

The relationship between the magnetic field generated and the convergence of the above-described change in the deflection current will be described below with reference to FIG.

First, when the deflection amount is small and the deflection angle is θ1 or less, the inductance of the auxiliary coils 4a and 4b is large, so that no current flows through the auxiliary coils 4a and 4b, so that the auxiliary deflection winding coils 1ab and 1bb are also supplied. Since no deflection current flows and there is no deflection magnetic field generated by the sub-deflection winding coils 1ab and 1bb, the deflection magnetic field is only from the main deflection winding coils 1aa and 1ba in this range. Therefore, the deflection magnetic field in this range becomes a pincushion magnetic field that is almost uniform, and becomes an ignition surface (ignition surface θ1 shown in FIG. 5) suitable for convergence that matches the center of the screen.

Next, when the deflection amount is large and the deflection angle is θ2, the inductance of the auxiliary coils 4a and 4b decreases, so that a current flows in the auxiliary coils 4a and 4b, and therefore the auxiliary deflection winding coils 1ab and 1bb are also deflected. Current flows,
The magnetic field generated from this deflection yoke is the main deflection winding coil 1a.
The resultant magnetic field is a composite magnetic field of a, 1ba and sub-deflection winding coils 1ab, 1bb. Therefore, the deflection magnetic field in this range becomes a synthetic magnetic field of a pincushion magnetic field and a strong pincushion magnetic field that are almost uniform, and becomes an ignition surface (ignition surface θ2 shown in FIG. 5) suitable for convergence that matches the peripheral portion of the screen.

As a result, the overall convergence quality of the cathode ray tube screen is greatly improved.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to FIGS.

FIG. 6 is a perspective view of an auxiliary circuit according to the second embodiment of the present invention. In FIG. 6, 9 is a disk-shaped permanent magnet having N poles and S poles diagonally, and 10 is the center point of the disk-shaped permanent magnet. The disk-shaped permanent magnet 9 has a structure that rotates about a center point 10. In this case, by rotating the permanent magnet 9, the auxiliary coils 4a, 4b
The magnetic bias applied to the can be changed by its rotation angle.

That is, as shown in FIG. 7, the magnetic saturation characteristic curve of FIG. 4 can be moved by rotating the permanent magnet 9. As an example, in FIG. 7, the magnetic saturation curve is moving to the right.

In such a case, the positions of the deflection amounts on the left and right of the screen are different, and FIG. 8 is a diagram for explaining the cathode ray tube screen of FIG. 3 and the deflection angle when scanning the same. . That is, the positions of the deflections θ1 and θ2 on the left and right of the screen are different, and the deflection is performed only by the main deflection winding coils 1aa and 1ba, and by the combination of the main deflection winding coils 1aa and 1ba and the sub deflection winding coils 1ab and 1bb. The positional relationship of the range to be moved moves to the left of the screen.

As a result, even if the cathode-ray tube screen 8 has a manufacturing variation, for example, and an imbalance occurs on the left and right of the screen, the disk-shaped permanent magnet 9 is rotated to weaken the bias applied to its poles. It can be resolved.

[0032]

As is apparent from the above description, according to the present invention, the horizontal deflection coil is divided into the main deflection winding coil and the sub-deflection winding coil, and the permanent magnet and its magnetic path are formed into a closed circuit. An auxiliary circuit with an auxiliary coil
By connecting the auxiliary coil and the sub-deflection winding coil in series, a deflection magnetic field only in the main deflection winding coil and a deflection magnetic field obtained by combining the main deflection winding coil and the sub-deflection winding coil are separated depending on the amount of deflection. Scanning will be performed, and the necessary deflection magnetic field can be generated according to the scanning range.
You can get a screen with less convergence error,
Further, by making the permanent magnet disk-shaped and rotating the permanent magnet so that the magnetic bias can be varied, it is possible to eliminate variations in manufacturing of, for example, a cathode ray tube.

[Brief description of drawings]

FIG. 1A is a front view of a horizontal deflection coil according to an embodiment of the present invention, and FIG. 1B is a circuit diagram of the horizontal deflection coil.

FIG. 2A is an explanatory diagram of an auxiliary circuit of the horizontal deflection coil, and FIG. 2B is an explanatory diagram of magnetic flux of the auxiliary circuit of the horizontal deflection coil.

FIG. 3 is an explanatory view of a cathode ray tube screen and a deflection angle when scanning the same.

FIG. 4 is a magnetic saturation characteristic diagram of the auxiliary coil.

FIG. 5 is an explanatory diagram of a change in deflection current and a relationship between a generated magnetic field and convergence.

FIG. 6 is a perspective view of an auxiliary circuit according to a second embodiment of the present invention.

FIG. 7 is a magnetic saturation characteristic diagram that moves by rotating a permanent magnet.

FIG. 8 is an explanatory view of the deflection angle and the positional relationship of the cathode ray tube screen of the second embodiment of the present invention.

FIG. 9 is a side view of a conventional deflection yoke device.

FIG. 10 is a schematic diagram of electromagnetic deflection using a horizontal deflection coil.

FIG. 11 is a diagonal side view of a 29-inch cathode ray tube.

FIG. 12 is an explanatory diagram of a state of an electron beam in a cathode ray tube.

FIG. 13 is an explanatory diagram of a convergence error due to a strong pincushion magnetic field.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Horizontal deflection coil 1aa, 1ba Main deflection winding coil 1ab, 1bb Sub deflection winding coil 4a, 4b Auxiliary coil 5 Permanent magnet 9 Disk-shaped permanent magnet

Claims (2)

[Claims] 1. A deflection yoke device comprising a horizontal deflection coil, a vertical deflection coil and a core made of a magnetic material, wherein the horizontal deflection coil is divided into a main deflection winding coil and a sub deflection winding coil, and a permanent magnet and its A deflection yoke device in which an auxiliary circuit including an auxiliary coil is provided in a magnetic circuit having a closed magnetic circuit, and the auxiliary coil and the sub-deflection winding coil are connected in series. 2. The permanent magnet used in the auxiliary circuit has a disk shape having N poles and S poles diagonally and has a structure of rotating around a center point, and by rotating it, a magnetic field flowing in a magnetic circuit. 2. The deflection yoke device according to claim 1, wherein the magnetic field strength changes depending on the rotation angle of the magnetic field and the current flowing through the auxiliary coil is controlled.