JPS597724Y2 - deflection yoke - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a deflection yoke used in an in-line multi-electron beam type color cathode ray tube.

In a shadow mask type color cathode ray tube, the three electron beams must always strike each phosphor dot correctly during deflection, otherwise color shifts will occur in the reproduced image and the image quality will be greatly impaired. , so-called convergence correction is essential.

Therefore, in the past, various convergence devices and circuits were added, but this made the structure complicated and required complicated work to adjust the convergence, resulting in a significant increase in cost and problems in terms of reliability. tended to occur.

However, in recent years, a shadow mask type cathode ray tube with three electron guns arranged in-line has been developed, and by combining this with a deflection yoke in which the horizontal deflection magnetic field is pincushion-shaped and the vertical deflection magnetic field is barrel-shaped. It has been discovered that convergence characteristics can be improved, and it has become possible to obtain sufficient convergence characteristics without using special correction means such as a correction circuit.

An example of a deflection yoke used for such a so-called self-convergence system is shown in FIG.

This deflection yoke is of a so-called semi-toroidal type, and in the figure, 1 represents the entire deflection yoke, and 2
3 is a horizontal deflection coil, 3 is a winding of a vertical deflection coil, 4 is a ring-shaped magnetic core, and 5 is a separator made of plastic or a shaped article.

By making the horizontal deflection coil 2 a hollow shape and the vertical deflection coil a toroidal shape using the core 4, a self-conversion type deflection yoke is obtained by making the horizontal deflection magnetic field a pin cushion shape and the vertical deflection magnetic field a barrel shape. ing.

By the way, the pincushion-like deflection distortion that usually occurs at the left and right edges of the image plane of a television receiver, so-called pincushion distortion, is essentially distortion caused by the fact that the image reproduction surface of the cathode ray tube is not spherical but flat. In most color television receivers that use a self-convergence system, the vertical deflection magnetic field produced by the deflection yoke is particularly barrel-shaped as described above, so pincushion distortion tends to further increase, and convergence compensates for this. Although it is possible to obtain an image with less color shift, it has the disadvantage that the image plane becomes severely distorted.

Therefore, in order to correct this pincushion distortion at the left and right edges of the image plane, a pincushion distortion correction circuit was provided, but after that, the shape of the vertical deflection magnetic field was changed along the axial direction of the deflection yoke using only the deflection yoke. It was discovered that pincushion distortion could be reduced by making the shape of the vertical deflection magnetic field barrel-shaped on the electron gun side to enable self-convergence correction, and making the shape of the magnetic field pincushion-shaped on the image side. Deflection yokes that generate vertical deflection magnetic fields have become widely used.

This is because convergence characteristics are affected by the shape of all parts of the vertical deflection magnetic field from the electron gun side to the image plane side, whereas pincushion distortion (2) is affected by the shape of the vertical deflection magnetic field on the image plane side. Based on the recognition of the fact that it is dominant.

Therefore, we have developed an example of a vertical deflection coil in which the shape of the magnetic field on the electron gun side is barrel-shaped and the shape of the magnetic field on the image plane side is pincushion-shaped, making it possible to improve convergence characteristics and reduce pincushion distortion. Shown in Figures a and t).

In the figure, a is a front view, b is a perspective view, 3 is a vertical deflection coil winding divided into two groups, 4 is a truncated circular magnetic core, and 6 is a winding. The conducting wire 7 forming the line 3 is the central axis.

Note that 4a and 4b are openings on the image plane side and the electron gun side of the core 4, respectively.

The feature of this vertical deflection coil is that the winding 3 of the deflection coil is
The core 4 is wound with a wide winding axis at the electron gun side opening 4b and a narrow winding width at the image plane side opening 4a, and the angle between the winding width on each side and the central axis 7 is u, q)2
This relationship allows the vertical deflection magnetic field to be barrel-shaped on the electron gun side and pincushion-shaped on the image side, improving convergence and reducing pincushion distortion. It is possible to obtain a deflection yoke with a

However, in order to correct both convergence characteristics and pincushion distortion using only the shape of the vertical deflection magnetic field, it is necessary to create a pincushion-shaped magnetic field on the image plane side, but a stronger barrel-shaped magnetic field on the electron gun side. Therefore, if we try to achieve this with a vertical deflection coil as shown in Figure 2 a and b, the relationship between the angles formed by the winding widths,
We must further emphasize ψ1〉no.

However, in this case, the conductive wire 6 that makes up the winding 3 becomes more oblique and becomes slippery as shown by the arrow 8, making the winding work difficult.

Therefore, in reality, it is not possible to set the relationship between the angles and the angles to a sufficiently satisfactory condition, and therefore, it is not possible to sufficiently correct both the convergence characteristic and the pincushion distortion.

Furthermore, this drawback is particularly noticeable in the case of cathode ray tubes that exhibit strong pincushion distortion, such as wide-angle deflection cathode ray tubes whose deflection angle reaches 90° or even 110°.
In the case of .degree., the angle .phi.1 is required to be 150.degree. or more and 80.degree. or less, which has the disadvantage that it is almost impossible to apply.

Therefore, in order to eliminate this drawback, it is necessary to create a vertical deflection magnetic field with a strong barrel shape on the electron gun side of the deflection yoke and a strong pincushion shape on the image side, without relying only on the winding state of the vertical deflection coil winding 3. must be able to take shape independently.

Among these methods, as an example of a method of making the shape of the vertical deflection magnetic field into a strong barrel shape on the electron gun side, the inventors have proposed a method as shown in FIG. 3.

This FIG. 3 is a front view of the vertical deflection coil seen from the image plane side as in FIG. 2a, and 8 is a magnetic piece made of permalloy or the like.

This magnetic piece 8 is provided on the inner surface of the winding 3 of the deflection coil near the electron gun side, and functions to attract the magnetic flux generated by the vertical deflection magnetic field and deform only the shape of the magnetic field near the electron gun side into a barrel shape.

Therefore, according to this method, the magnetic field shape on the electron gun side of the vertical deflection magnetic field formed by the deflection coil winding 3 and the ring-shaped magnetic core 4 can be further emphasized into a barrel shape, and the in-line multi-electron beam It can be applied to color cathode ray tubes to provide sufficient self-convergence characteristics, but it is not possible to emphasize the pincushion shape of the magnetic field on the image side, so pincushion distortion cannot be sufficiently corrected as is. There was a drawback.

In addition, as an example of a method of emphasizing the shape of the vertical deflection magnetic field on the image plane side into a pincushion shape, for example, Fig. 4a,
A method using a ring-shaped magnetic core 4 as shown in l) has been proposed.

In the figure, reference numeral 10 denotes a pair of wing-shaped protrusions provided on the outer periphery of the core 4 on the image plane side, approximately symmetrically with respect to the central axis 7, and the winding 3 including these protrusions 10 is wound. It has become so.

Note that FIG. 3A is a front view as seen from the image plane side, and FIG. 7B is a top view, in which the winding 3 is omitted.

By providing these protrusions 10, it is possible to prevent the winding 3 from spreading on the image plane side, so that the angle explained in FIG. 2 can be narrowed, and the angle explained in FIG. The shape of the vertical deflection magnetic field is barrel-shaped as shown by the magnetic flux 12, and as a result of the projections 10 acting as magnetic poles as shown in FIG. 6, a magnetic flux appears between these projections 10, and the overall shape is Since the pincushion shape is emphasized as shown by the magnetic flux 12, left and right pincushion distortion can be reduced.

However, even with this method, it is still difficult to obtain a pincushion deflection magnetic field of sufficient strength, and there is a drawback that pincushion distortion cannot be sufficiently corrected.

An object of the present invention is to provide a deflection yoke that can emphasize the shape of the vertical deflection magnetic field on the image plane side into a pincushion shape independently of the shape of the magnetic field on the electron gun side, while eliminating the drawbacks of the prior art described above. There is something to do.

In order to achieve this purpose, the present invention provides a protrusion on the image plane side of the ring-shaped magnetic core around which the vertical deflection coil winding of the deflection yoke is wound. The present invention is characterized in that the shape of the deflection magnetic field is further emphasized into a pincushion shape, and the pincushion-shaped magnetic field is formed even to the outside of the deflection yoke toward the image plane side.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 7a, 1) shows an embodiment of the ring-shaped magnetic core 4 according to the present invention, where a is a front view and b is a top view.

In the figure, reference numeral 11 denotes protrusions of a magnetic material, and four protrusions (two pairs in total) are provided at the end of the core 4 on the image plane side, one pair each at symmetrical positions with respect to the central axis 7.

8a and 8l) also show another embodiment of the core 4, in which the present invention is applied to the conventional example shown in FIG. It was established.

It should be noted that in these embodiments of the present invention, the protrusion 11 always has a shape that projects further outward from the image plane side of the core 4 toward the image plane.

Fig. 9 shows the state in which the vertical deflection coil winding 3 is wound around the core 4 shown in Fig. 7 a, l), and Fig. 10 shows the state in which the vertical deflection coil winding 3 is wound around the core 4 shown in Fig. 8 a, l). This is used as the vertical deflection coil of the deflection yoke.

Next, the effects of the present invention will be explained.

Figures 11a and l) show the vertical deflection magnetic field according to the embodiment shown in Figure 9, and Figure 11a is a view from the image plane side;
b is a view seen from the top.

As is clear from the state of the magnetic flux 12 in figure a, since the protrusions 11 are present, these protrusions 11 act as magnetic poles, and since magnetic flux is generated between them, the shape of the deflection magnetic field near the image plane is focused. It can be seen that the cushion shape is emphasized.

In addition, at this time, as shown in FIG. Since the pincushion-shaped deflection magnetic field spreads to the outside of the surface side, the emphasis effect of the pincushion shape on the vertical deflection magnetic field on the image side of the deflection yoke is significantly increased, and the winding of the vertical deflection coil Even without special consideration given to the conditions, a pincushion-shaped deflection magnetic field of sufficient strength to correct pincushion distortion can be created, and a deflection yoke can be obtained which largely eliminates the drawbacks of the prior art.

12a and l) show the deflection magnetic field obtained by the embodiment shown in FIG. 10, where a is a view seen from the image plane side, b is a view from above, and FIG. It can be seen that a pincushion-shaped deflection magnetic field extending to the outside of the image plane side of the core 4 can be obtained as in the case of FIG.

In the embodiment shown in FIG.
Since it is provided on the image plane side of 0, it also has a pincushion-shaped deflection magnetic field enhancement effect by the wing-like protrusion 10, so it is possible to obtain a particularly excellent pincushion-shaped enhancement effect, and the pincushion distortion is large. Even if it is applied to wide-angle cathode ray tubes where this phenomenon is likely to occur, a sufficient corrective effect can be expected.

As explained above, according to the present invention, the shape of the magnetic field on the electron gun side of the deflection yoke is determined by a simple structure in which the protrusion 11 is provided on the ring-shaped magnetic core 4 around which the vertical deflection coil is wound. Since a strong pincushion-shaped vertical deflection magnetic field can be formed independently on the image plane side, the drawbacks of the conventional technology can be fully eliminated, and a barrel-shaped vertical deflection magnetic field can be generated on the electron gun side. A self-convergence type deflection yoke can be easily obtained by combining it with a means for deflection, and a sufficiently strong pincushion type vertical deflection magnetic field can be obtained, so it can be combined with a wide-angle deflection type color cathode ray tube. This makes it possible to fully utilize the self-convergence characteristic while sufficiently correcting pincushion distortion on the image plane, thereby providing a deflection yoke that is useful for reproducing color television images of excellent image quality.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing a conventional example of a semi-toroidal deflection yoke, Fig. 2 a and l) are front and perspective views showing a conventional example of a vertical deflection coil in a self-convergence type deflection yoke, and Fig. 3 is a perspective view showing a conventional example of a vertical deflection coil in a self-convergence type deflection yoke. A front view of a conventional example of a vertical deflection coil in which the shape of the vertical deflection magnetic field on the electron gun side can be made into a strong barrel shape. Front and top views showing conventional examples of vertical deflection coils that can be shaped like
Fig. 5 is a conceptual diagram showing an example of a barrel-shaped vertical deflection magnetic field, Fig. 6 is a conceptual diagram showing a vertical deflection magnetic field obtained by the deflection coils shown in Fig. 4 a, l), and Fig. 7 a, b, and Figures 8a and l) are front and top views showing different embodiments of the ring-shaped magnetic core used in the embodiment of the present invention, and Figures 9 and 10 are vertical views in the present invention, respectively. A front view showing an example of a deflection coil.
Figures 11a, l) and 12a, l) are both conceptual diagrams showing the shape of the vertical deflection magnetic field obtained by the embodiment of the present invention, where a is a view seen from the front and b is a view from above. It is a diagram. 3... Vertical deflection coil winding, 4...
Ring-shaped magnetic core, 7... Central axis of deflection yoke, 10... Vane-shaped protrusion, 11...
Protrusion, 12...Magnetic flux.

Claims (1)

[Claims for Utility Model Registration] (l) In a deflection yoke consisting of a toroidal vertical deflection coil, the image plane side of the ring-shaped magnetic core around which the vertical deflection coil is wound is symmetrical with respect to the central axis of the deflection yoke. At least two pairs of protrusions made of a magnetic material protruding toward the image plane are provided at positions such that a pincushion-shaped vertical deflection magnetic field is formed on the outside of the deflection yoke on the image plane side. A deflection yoke characterized by: (2) A utility model registration claim characterized in that the protrusion provided on the image surface side of the ring-shaped magnetic core is provided at the end of the ring-shaped magnetic core on the image surface side. Deflection yoke according to item 1. (3) A protrusion provided on the ring-shaped magnetic core is located on the image plane side of the core, approximately symmetrically with respect to its central axis, and along approximately the same plane as the edge of the core on the image plane side. At least two portions extending radially from the outer periphery of the core.
The first claim of the utility model registration, which is characterized in that the wing-like projections made of a pair of magnetic materials are provided on the image plane side.
Deflection yoke as described in section.