JP2751231B2 - Deflection device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CRT (cathode ray tube) deflection device, and more particularly to a structure for correcting image distortion.

[Summary of the Invention]

The winding of the wire of the vertical deflection coil with respect to the core is formed in a reverse diagonal winding, and the winding angle in the circumferential direction is larger on the screen side than on the electron gun side. Absorbs more magnetic flux from the vertical deflection coil and generates more leakage magnetic flux through the poles of the cross arm, which enhances the effect of correcting image distortion by the cross arm. It is.

[Conventional technology]

The CRT is provided with a deflecting device at its neck, and the magnetic field generated by the deflecting device deflects the direction of the electrons generated by the electron gun. The deflection device is composed of two types of coils, a horizontal deflection coil and a vertical deflection coil. The horizontal deflection coil is usually composed of a clad coil and is disposed inside the bobbin. On the other hand, the vertical deflection coil is wound in a toroidal shape around a ferrite core, and is arranged on the outer peripheral side of the bobbin.

In particular, in the structure of the conventional vertical deflection coil, as shown in FIG. 6, the wire 1 is radially wound around the outer periphery of the ferrite core 2 so that the direction of the wire 1 coincides with the direction of the generatrix. . In addition, a vertical deflection coil 1 having a normal oblique winding as shown in FIG. 7 is used. The coil 1 is wound on the core 2 such that the winding angle on the front side is smaller than that on the rear side. The distribution of the generated magnetic field is adjusted by such winding.

[Problems to be solved by the invention]

In a color television receiver, in order to cause three electron beams to converge on a screen only by a deflecting device, a horizontal deflection coil normally generates a pincushion-type deflection magnetic field and a vertical deflection coil generates a barrel-type deflection magnetic field. Make up. On the other hand, in order to prevent the raster from becoming a pincushion type, it is preferable that both the magnetic field generated by the horizontal deflection coil and the vertical deflection coil be a pincushion type deflection magnetic field. As a method for achieving both convergence correction and image distortion correction, for example, Japanese Utility Model Publication No. 63-1437
A cross arm as disclosed in Japanese Patent Publication No. 0 is used. Such a cross arm is a magnetic body that absorbs a vertical deflection magnetic field leaking from a deflection yoke, particularly its vertical deflection coil, and guides it to the screen side to form a pincushion-type correction magnetic field. However, even if such a cross arm is used, the vertical deflection coil generally gives priority to convergence and determines the distribution of its magnetic field, so there is a limit to the correction of the magnetic field by the cross arm, and it is not necessarily limited. Sufficient effects were not obtained.

The present invention has been made in view of such a problem, and an object of the present invention is to provide a deflecting device in which a cross arm exhibits a higher effect.

[Means for solving the problem]

The present invention provides a deflecting device in which a cross arm is attached to an outer peripheral portion of a vertical deflection coil and image distortion is corrected by a leakage magnetic flux induced through a magnetic pole of the cross arm. The winding angle in the circumferential direction with respect to the core is such that the screen side is larger than the electron gun side.

[Action]

Therefore, by forming the vertical deflection coil in the opposite oblique winding, it is possible to increase the leakage magnetic flux without changing the convergence characteristics. Therefore, the amount of magnetic flux absorbed by the cross arm increases, and the effect of correcting image distortion increases.

〔Example〕

FIG. 3 shows a CRT deflecting device according to an embodiment of the present invention. The bobbin 10 is formed of a synthetic resin molded body, and has a structure divided into two right and left parts. And bobbin 10
Inside, a horizontal deflection coil 11 is wound. The horizontal deflection coil 11 is formed by winding a wire rod into a hollow shape, and the magnetic field generated by the coil causes the electron beam to swing right and left. Bobbin 10
A vertical deflection coil 12 is arranged outside the box. The vertical deflection coil 12 is wound around a ferrite core 13 in a toroidal shape, and is vertically divided into two parts.

A cross arm 14 is arranged on the outer peripheral side of the vertical deflection coil 12. The cross arm 14 is divided into two parts, left and right, and each of the divided cross arms is provided with a pair of magnetic poles 15 above and below. A locking piece 18 is continuously provided on the bobbin 10, and a claw 19 is provided at the tip of the locking piece 18, and the locking piece 18 is inserted into a locking hole 20 of the cross arm 14. Thus, the cross arm 14 is held on the bobbin 10. A circumferential end of the cross arm 14 is pressed by a rib 23 provided on the bobbin 10, and a side end of the magnetic pole 15 is pressed by a presser 24.

As shown in FIGS. 1 and 2, the vertical deflection coil 12 constituting the deflection device is formed in a reverse oblique winding. That is, the wire is wound so as to be inclined in the direction opposite to the normal oblique winding shown in FIG. Therefore, this
The winding angle of the wire around the ferrite core 13 is different between the front side and the rear side. That is, as shown in FIG. 2, the winding angle on the front side (screen side) is made larger than that on the rear side (electron gun side), so that more magnetic flux is guided to the cross arm 14. ing.

As described above, in the deflection device according to the present embodiment, the vertical deflection coil 12 wound in a toroidal shape is a so-called reverse oblique winding in which the front side is wider. Therefore, compared with the case of the normal winding shown in FIG. 6 or the case of the normal oblique winding shown in FIG. 7, the leakage magnetic flux at the opening on the front side (screen side) increases. Such a leakage magnetic flux is absorbed by the cross arm 14 as shown in FIG. Then, the magnetic flux is guided to the screen side through the magnetic poles 15 of the cross arm 14 to induce a leakage magnetic flux 28 for correcting image distortion.

Therefore, by making the vertical deflection coil 12 reversely obliquely wound,
With little change in convergence characteristics, it is possible to increase the leakage magnetic flux on the deflection yoke opening side and improve image distortion in the barrel
Can enhance the effect of image distortion correction.

For confirmation, six types of deflection yokes were actually created by combining the winding method of the vertical deflection coil and the presence / absence of the cross arm, and the image distortion was measured based on the results. Note that the image distortion is measured by the following calculation formula for the upper and lower pin distortions shown in FIG.

The results of image distortion measurement based on the above are shown in the following table.

Measurement conditions CRT: 25FX (25 inch, 110 ° deflection, aspect ratio 4: 3) Deflection yoke: Model Y25FXA Vertical coil core: CR524A Vertical deflection coil: φ0.43 mm, 311 turns Distribution: SY-178 type Cross arm: CA178 Horizontal deflection Current 6.8A _PP vertical deflection current 1.55A _PP CRT anode voltage 29kv As is clear from the above data, the one without cross arm has relatively poor image distortion, and the Distortion is greatly improved. Regarding the relationship between the cross arm 14 and the winding of the vertical deflection coil 12, the reverse oblique winding has the best image distortion of 1.35%, followed by 1.91% when the cross arm is attached in the normal winding method. Has become. On the other hand, the combination of the cross arm 14 and the oblique winding has an image distortion of 2.1%, and the image distortion becomes considerably conspicuous. As is clear from these results, it has been confirmed that the image distortion can be further improved by forming the vertical deflection coil 12 in a reverse oblique winding and combining it with a cross arm.

〔The invention's effect〕

As described above, in the present invention, the vertical deflection coil is formed in a reverse oblique direction so that the winding angle in the circumferential direction with respect to the core is larger on the screen side than on the electron gun side. Accordingly, it is possible to increase the leakage magnetic flux on the deflection yoke opening side without changing the convergence characteristic, and to enhance the effect of the image distortion correction by the cross arm.

[Brief description of the drawings]

FIG. 1 is a plan view of a vertical deflection coil of a deflection device according to one embodiment of the present invention, FIG. 2 is a rear view of the same, FIG. 3 is an exploded perspective view of the whole, and FIG. FIG. 5 is a front view of a screen showing an operation of correcting image distortion by a cross arm, FIG. 6 is a plan view of a conventional vertical deflection coil, and FIG. 7 is another conventional vertical deflection coil. FIG. 8 is a plan view of a screen showing the evaluation of image distortion. The names of the main parts in the drawings are as follows. 10 Bobbin 11 Horizontal deflection coil 12 Vertical deflection coil 13 Core 14 Cross arm 15 Magnetic pole 18 Locking piece 20 Locking piece 28 Leakage magnetic flux

Claims (1)

(57) [Claims] 1. A deflecting device in which a cross arm is attached to an outer peripheral portion of a vertical deflection coil, and image distortion is corrected by a leakage magnetic flux induced through a magnetic pole of the cross arm. A deflecting device wherein the winding angle in the circumferential direction with respect to the core is larger on the screen side than on the electron gun side.