JPS62125789A - Deflecting yoke device - Google Patents

Abstract

PURPOSE:To concentrate three electron beams within an allowable error through all areas of a cathode ray tube screen by correcting the magnetic field of a deflecting yoke so as to have a cross misconvergence of the same quality in a formation by using a magnetic piece. CONSTITUTION:Between horizontal deflecting coils 1, 2 and vertical deflecting coils 3, 4, the four magnetic pieces 6, 7, 8, 9 made of a silicon steel plate or 'Permalloy(R)' or the like are disposed. When constituting in such a manner, the deflecting magnetic field in a cathode ray tube neck part is locally weakened and a side end part of the screen of a horizontal deflecting magnetic field becomes the strong horizontal deflecting magnetic field of one layer pincushion type. By using a correction circuit device obtained by dividing impedance coils 16, 17 and winding on two open magnetic pathscores 14, 15 for instance, a rod shape or a drum shape cores, respectively, a reverse cross misconvergence is generated. According to the constitution in which the correction circuit device and the magnetic piece are commonly used in the deflecting yoke, the concentration of the three electron beams is obtained through all the areas of the screen.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a deflection yoke device used in television screens and cathode ray tube displays.

(Conventional Technique? II) Recently, in-line cathode ray tubes, in which three electron beams are emitted in a horizontal row, have been widely used.

In this cathode ray tube, the horizontal deflection magnetic field of the deflection yoke is made into a pincushion-shaped magnetic field, and the vertical deflection magnetic field is made into a barrel-shaped magnetic field, so that the three electron beams can be concentrated within a predetermined tolerance over the entire screen using only the deflection yoke. It is possible to do so.

That is, in the case of a cathode ray tube with a small deflection angle of 70 degrees, for example, it is possible to keep both the primary concentration error and the secondary concentration error within the permissible value. However, when the deflection angle becomes large, for example 110 degrees, the distance between the virtual spherical surface and the screen as seen from the center of deflection increases, and not only the primary concentration error and the secondary concentration error but also higher-order concentration errors are kept within the allowable value at the same time. Deflection yoke! M construction will be difficult. Particularly in cathode ray tube displays that display character information, satisfactory beam concentration cannot be achieved by simply attaching magnetic pieces or magnet pieces to the deflection yoke. For this reason, it is possible to use a convergence circuit, but it is difficult to accurately match the corrected current waveform with the misconvergence mode, resulting in the disadvantage that misconvergence remains and a high-quality screen cannot be obtained.

(Problems to be Solved by the Invention) The present invention provides a deflection yoke device in which the concentration of six electron beams over the entire area of a cathode ray tube screen is within tolerance.

(Means for Solving the Problems) Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. By adding harmonic magnetic field components to the fundamental magnetic fields of the horizontal deflection coil and the vertical deflection coil, a deflection magnetic field with astigmatism on the deflection axis can be obtained. That is, by using the horizontal deflection coil as a pincushion-shaped deflection magnetic field and the vertical deflection coil as a barrel-shaped deflection magnetic field, it is possible to construct a deflection yoke in which the primary concentration error and the secondary concentration error are reduced.

However, as the deflection angle increases, it becomes difficult to construct a deflection yoke having harmonic magnetic field components having a specific shape in the direction of the deflection axis, resulting in misconvergence as shown in FIG. That is, the raster by the screen beam R is
Regardless of whether it is concentrated at any point on the Y-axis or the Y-axis, the eswing (
S-ing) misconvergence occurs, and positive cross misconvergence occurs at positions dividing the Y-axis direction into four equal parts.

The coexistence of these different forms of misconvergence cannot be eliminated by simple means such as adding a magnetic piece, and even if a convergence circuit is used, misconvergence remains in a part of the screen, making it difficult to improve image quality. Can not.

In FIG. 4, the X-axis direction quarter-dividing device S at the upper and lower ends in the Y-axis direction, the left and right ends S in the X-axis direction at the four-quarter positions in the Y-axis direction, and the quarter-dividing position St as the center. However, in the present invention, a magnetic piece is used to correct the magnetic field of the deflection yoke so that the shape becomes homogeneous or loss-misconvergence occurs.

To describe a specific example of such a deflection yoke, as shown in FIG. The vertical deflection coil 3.4 is wound toroidally around the deflection core 5 and is configured to generate a barrel-shaped vertical deflection magnetic field. Note that the coil separator is excluded to simplify the drawing.

Between the horizontal deflection coils 1, 2 and the vertical deflection coil 6.4, there are four magnetic pieces 6.4 made of silicon steel plate, permalloy, etc.
7. 8. 9 is placed. The magnetic piece may be attached to the coil or may be attached to a coil separator (not shown). Horizontal deflection coil 1 with magnetic piece 6.7°8.9
．． 2, as shown in FIG. 3, the coil portion extending in the tube axis direction of the cathode ray tube, the longitudinal portion 11, 12 of the deflection coil, is provided in contact with the window portion 10 at the screen side end. It will be done. Note that 16 is a coil separator.

With this configuration, most of the horizontal deflection magnetic field generated from the horizontal deflection coil 1.2 near the magnetic pieces 6, 7° 8.9 passes through a magnetic path including the magnetic pieces. Therefore, the deflection magnetic field within the neck of the cathode ray tube is locally weakened, and the screen-side end of the horizontal deflection magnetic field becomes a stronger pincushion-shaped horizontal deflection magnetic field. In other words, the effect is similar to that of cutting out a part of the horizontal deflection coil where the magnetic piece is located.

On the other hand, the vertical deflection magnetic field generated from the vertical deflection coil 3.4 is transmitted to the magnetic piece 6. 7. 8. Since a magnetic field close to 9 is passed through the magnetic path including the magnetic piece, the magnetic field passing through the neck of the cathode ray tube is locally deformed.

In this way, by adding a partially modified harmonic magnetic field component to the fundamental magnetic field of the deflection yoke, astigmatism on the deflection axis can be locally changed.

As a result, as shown in FIG. 5, the S swing misconvergence at the upper and lower ends in the Y-axis direction changes to cross misconvergence. In other words, the raster by the R beam and the raster by the B beam converge and intersect at YT and YB on the Y axis, but the reverse loss misconvergence at both ends of the X axis is reversed to the positive cross misconvergence, and the amount PQv increases. In this case, the misconvergence at the four equally divided positions S, , S, in the Y-axis direction is only slightly worse.

A screen in which such misconvergence exists is below a permissible value and cannot be put to practical use. For this reason, the present invention incorporates a correction circuit device as shown in FIGS. 1 and 6 into the deflection yoke. That is, two open magnetic path cores 14.15
For example, impedance coils 16 and 17 are separately wound around each of the rod-shaped or drum-shaped cores. The control coil 18 is wound around the two open magnetic path cores 14, 15 to apply a common control magnetic field. The control coil 18 is connected in series with the vertical deflection coil 6.4 and receives a vertical deflection current of 1 V from the vertical deflection circuit 19. Impedance coil 1
6.17 is the horizontal deflection s il1.

2, and each series circuit receives a horizontal deflection current IH from the horizontal deflection circuit 20. Further, the open magnetic path core 14.15 is statically magnetically biased by two permanent magnets 21.22 having the same poles facing each other.

FIG. 6 shows the directions of the magnetic flux pH, , 12511 generated by the impedance coil 16.17, the magnetic flux ρV generated from the control coil 18, and the magnetic flux 125M+, ρM generated from the permanent magnet 24.25. The direction of the magnetic flux generated from the impedance coils 16, 17 and the control coil 18 changes every half cycle of the respective deflection currents. Therefore, the direction of magnetic flux in FIG. 6 indicates the direction of magnetic flux at a certain point in time.

In this case, the core legs 14a, 15a are ΩV+ρM
, which is equivalent to a decrease in magnetic permeability, and the inductance of the impedance coil 17 decreases. That is, since the impedance of the impedance coil 17 becomes small, the current flowing through the horizontal deflection coil 2 is not limited.

On the other hand, the core legs 14b and 15b are biased to CV12'M+, which is equivalent to increasing their magnetic permeability, so the impedance of the impedance coil 16 increases, and the current flowing through the horizontal deflection coil 1 becomes small.

This operation is explained at specific points in the vertical deflection period.

In reality, the current flowing through the horizontal deflection coil 1.2 is amplitude-modulated in the vertical deflection period.

When such a correction circuit device is used, reverse cross-mistake convergence occurs as shown in FIG. The strength of this misconvergence can be changed by adjusting the magnetic flux density of the permanent magnets 21, 22.

The reverse cross-misconvergence shown in FIG. 7 is exactly the opposite misconvergence to the normal cross-misconvergence shown in FIG. 4 when the magnetic piece is added. Therefore, by configuring the deflection yoke to include the above-mentioned correction circuit device and magnetic piece, it is possible to eliminate the occurrence of complex misconvergence, in which the S-swing misconvergence and the cross-swing misconvergence coexist, as shown in Fig. 4. Therefore, 3N beams can be concentrated over the entire area of the screen.

(Effects of the Invention) As described above, the present invention uses the correction circuit device and the magnetic piece in combination, so that the deflection angle for the electron beam can be increased by, for example, 10.
It is possible to eliminate the troublesome misconvergence that inevitably occurs due to the structure of the deflection yoke and cathode ray tube when the angle increases from 0 to 114 degrees, and to keep the concentration of the 3N beam within the tolerance over the entire screen area. It is possible to obtain high-quality images.

[Brief explanation of drawings]

FIG. 1 is a circuit connection diagram of a deflection yoke device of the present invention, FIG. 2 is a partial schematic sectional view of the deflection yoke device of the present invention, FIG. 3 is a front view of the deflection yoke device of the present invention, and FIG. An explanatory diagram of misconvergence caused by the conventional deflection yoke; FIG. 5 is an explanatory diagram of positive cross misconvergence that occurs when some functions of the deflection yoke device of the present invention are used; FIG. 6 is an explanatory diagram of misconvergence caused by the deflection yoke device of the present invention. FIG. 7 is a schematic configuration diagram showing one embodiment of the correction circuit device μ used, and is an explanatory diagram of reverse loss misconvergence that occurs when the circuit of FIG. 1 is used. In the figure, 1.2 is a horizontal deflection coil, 6.4 is a vertical deflection coil, and 6. 7. 8. 9 is a magnetic piece, 10 is a window, 11
．． 12 is a longitudinal part, 14.15 is an open magnetic path core, 16.
17 is an impedance coil, 18 is a control coil, 21
．． 22 is a magnet.

Claims (1)

[Claims] 1. A deflection yoke having a deflection core, a pair of saddle-shaped horizontal deflection coils that generate a pincushion-shaped horizontal deflection magnetic field, and a pair of vertical deflection coils that generate a barrel-shaped vertical deflection magnetic field, and a deflection yoke that is magnetically biased by a permanent magnet. A pair of impedance coils and a control coil are wound around a core, the impedance coil is connected in series with the horizontal deflection coil, and the control coil is connected in series with the vertical deflection coil. correction circuit means configured to control the impedance of the impedance coil so that the current flowing through the horizontal deflection coil is differentially changed in the vertical deflection period;
A deflection yoke device comprising a magnetic piece provided near the window so as to locally weaken the deflection magnetic field generated from the longitudinal portion forming the window of the horizontal deflection coil.