JP3334378B2 - Deflection yoke - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deflection yoke for improving the deflection sensitivity and can be applied to a cathode ray tube device such as a computer display device.

[0002]

2. Description of the Related Art Conventionally, in a deflection yoke, in a cathode ray tube device, a deflection center is set so that neck shadow does not occur, and the entire length is determined substantially by the deflection center.

That is, in this type of deflection yoke, a pair of horizontal deflection coils are arranged vertically so as to sandwich the neck of the cathode ray tube, and a horizontal deflection magnetic field crossing the neck of the cathode ray tube vertically by the pair of horizontal deflection coils. It is formed. In addition, a pair of vertical deflection coils are arranged on the left and right of the deflection yoke from outside the horizontal deflection coil so as to sandwich the neck of the cathode ray tube, and the pair of vertical deflection coils vertically traverse the neck of the cathode ray tube left and right. A magnetic field is formed.

Further, in the deflection yoke, a substantially conical cylindrical core is arranged outside the vertical deflection coil, and the core forms a magnetic circuit for the horizontal deflection coil and the vertical deflection coil. As a result, in the deflection yoke, the magnetic lines of force crossing the neck of the cathode ray tube are formed so as to circumvent the core and return to the original deflection coil, so that the leakage magnetic field can be reduced and electromagnetic deflection can be performed efficiently.

In the cathode ray tube apparatus, the horizontal deflection coil and the vertical deflection coil are driven to electromagnetically deflect the electron beam emitted from the electron gun, and the electron beam is raster-scanned. That is, when the electron beam emitted from the electron gun passes through the deflecting magnetic field, the scanning trajectory is bent and deflected up and down and left and right of the cathode ray tube, and then goes straight on the funnel portion of the cathode ray tube toward the front.

Therefore, in the cathode ray tube device, if this deflection center (ie, corresponding to the center of the magnetic field distribution of the deflection magnetic field) is set too close to the electron gun, the electron beam emitted toward the corner of the display screen will be During the run,
It collides with the inner wall surface of the neck, which obstructs the traveling of the electron beam at the corners and causes neck shadow.

For this reason, in the deflection yoke, the length of the deflection coil is extended to the front side of the cathode ray tube in comparison with the length of the neck of the cathode ray tube, whereby the deflection center is located at a predetermined position or more on the front side of the cathode ray tube. It is set to effectively avoid neck shadows.

[0008]

When the center of deflection is set on the front side of the cathode ray tube as described above, it is necessary to increase the deflection angle accordingly, and for this purpose, it is necessary to increase the deflection magnetic field. Therefore, if the deflection center can be shifted to the electron gun side, the deflection angle can be reduced accordingly, the deflection magnetic field can be reduced, the power consumption can be reduced, and the temperature rise of the deflection yoke can be reduced. it can.

Focusing on this, the central portion of the display screen of the cathode ray tube apparatus has a feature that no neck shadow occurs at the central portion of the display screen even if the deflection center is shifted to the electron gun side. . Therefore, in the deflection yoke, if the neck shadow at the corner portion can be effectively avoided, the deflection center can be shifted to the electron gun side and the deflection sensitivity can be improved accordingly.

When the deflection coil is extended to the front side of the cathode ray tube, the diameter of the cathode ray tube increases from the neck toward the funnel, so that the front end diameter of the deflection yoke must be increased accordingly. Therefore, in the deflection yoke, if the deflection center can be shifted to the electron gun side, the overall shape can be reduced in size and the weight can be reduced accordingly.

The present invention has been made in view of the above points, and effectively avoids neck shadows at corners.
It is an object of the present invention to propose a deflection yoke which can improve the deflection sensitivity as compared with the related art and can reduce the size.

[0012]

According to the present invention, there is provided a cathode ray tube which is held by a neck of a cathode ray tube.
In a deflection yoke for electromagnetically deflecting a cathode ray tube, a pair of horizontal deflection coils which are held opposite to each other with a neck of the cathode ray tube therebetween to form a horizontal deflection magnetic field, and a horizontal deflection coil is provided on the electron gun side of the cathode ray tube. A sub-coil, which is arranged to correspond to the coil and is induced by the horizontal deflection magnetic field to generate a back electromotive voltage, and a load circuit of the sub-coil, whose impedance decreases when the vicinity of the upper and lower ends of the display screen of the cathode ray tube is deflected. Be equipped.

Further, the load circuit comprises a primary winding and a secondary winding.
It is formed of a saturable reactor having a secondary winding, supplies a vertical deflection current to the primary winding, and connects the secondary winding to the sub-coil.

[0014]

When a sub-coil is provided corresponding to a horizontal deflection coil and generates a back electromotive voltage induced by a horizontal deflection magnetic field, the vicinity of the upper and lower ends of a display screen of a cathode ray tube is deflected with respect to the sub-coil. If a load circuit with a reduced impedance is connected, the sub-coil generates a magnetic field in a direction to cancel the horizontal deflection magnetic field when deflecting near the upper and lower ends of the display screen. Therefore, in the deflection magnetic field, the magnetic field distribution moves from the electron gun side to the display screen side.

In particular, if the load circuit is formed by a saturable reactor having a primary winding and a secondary winding, it is set so that the saturable reactor is saturated when the vertical deflection current increases.
When deflecting the vicinity of the upper and lower ends of the display screen, a magnetic field can be generated in a direction to cancel the horizontal deflection magnetic field.

[0016]

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

FIG. 2 is a side view showing a deflection yoke according to an embodiment of the present invention, with a partial cross section. FIG. 2
In the cross section, only the horizontal deflection coil 7 and the like are described, and description of other components is omitted. Here, in the deflection yoke 1, in the assembly process, after the horizontal deflection coil assembly 2 and the vertical deflection coil assembly 3 are combined, the core 4 is attached from the outside, and then the front cover 5 and the back cover 6 are attached. It is formed.

The core 4 is disposed outside the vertical deflection coil 8 by combining two ferrite cores so as to form a substantially conical cylindrical ring core. As a result, the core 4 forms a magnetic circuit of a horizontal deflection magnetic field and a vertical deflection magnetic field, so that the deflection yoke can efficiently perform electromagnetic deflection.

The vertical deflection coil assembly 3 is formed by winding a vertical deflection coil 8 around a separator forming a coil bobbin in a vertical winding step. The vertical deflection coil 8 is formed in a saddle shape by section winding. When the deflection yoke 1 is arranged on the cathode ray tube, the vertical deflection coil 8 is disposed outside the horizontal deflection coil assembly 2 so as to sandwich the neck of the cathode ray tube from left and right. 4 inside. Thereby, the vertical deflection coil 8 forms a vertical deflection magnetic field that crosses the neck of the cathode ray tube left and right.

On the other hand, the horizontal deflection coil assembly 2 is formed by winding a horizontal deflection coil 7 around a separator forming a coil bobbin in a horizontal winding step. At this time, the horizontal deflection coil 7 winds a prescribed magnet wire using the inner side surface of the separator and the projections formed on the front end surface and the rear end surface, thereby forming a saddle shape by section winding. The horizontal deflection coil 7 is
When the deflection yoke 1 is arranged on the cathode ray tube, the deflection yoke 1 is arranged inside the vertical deflection coil assembly 3 so as to sandwich the neck of the cathode ray tube from above and below. Thereby, the horizontal deflection coil 7 forms a horizontal deflection magnetic field that crosses the neck of the cathode ray tube up and down.

As further shown in FIG. 3, in this embodiment, the horizontal deflection coil assembly 2 is mounted on the electron gun side.
The sub-coil 9 is arranged, and in the deflection yoke 1, the deflection center moves to the display screen side near the upper and lower ends of the display screen by the sub-coil 9. In FIG. 3, a horizontal deflection coil formed by section winding is shown in a simplified manner.

The sub-coil 9 is formed by winding a magnet wire made of a self-fusing wire around a predetermined mold and then performing self-fusing to form an arc shape along the neck of the cathode ray tube and from above. When viewed, the magnet wire is formed so as to run in a rectangular shape. In the horizontal deflection coil assembly 2, a concave portion is formed on the outer side surface of the separator, and after positioning the sub-coil 9 using the concave portion,
Fix to the separator with tape. This allows the horizontal deflection coil assembly 2 to easily and reliably mount the sub coil 9.

At this time, the horizontal deflection coil assembly 2
Holds two sub-coils 9 so as to correspond to the horizontal deflection coil 7 held so as to face each other with the neck of the cathode ray tube interposed therebetween. Thereby, the horizontal deflection coil assembly 2 moves the sub-coil 9 to the rear end side of the horizontal deflection coil 7 (that is, to the electron gun side) so that the horizontal deflection magnetic field interlinks and corresponds to the horizontal deflection coil 7. Deploy.

When the sub-coils 9 are arranged so that the horizontal deflection magnetic fields are linked, the sub-coils 9
Induced by the horizontal deflection magnetic field, a counter electromotive voltage is generated in a direction to suppress the horizontal deflection magnetic field. In this case, the sub coil 9
Are held open in the sub-coil 9 so that only a counter electromotive voltage is generated.
The horizontal deflection magnetic field is maintained in a magnetic field distribution formed by the horizontal deflection coil 7.

On the other hand, if the terminals at both ends of the sub coil 9 are short-circuited, a current flows through the sub coil 9 due to the back electromotive force,
As a result, a magnetic field is formed by the sub-coil 9 in a direction to cancel the horizontal deflection magnetic field. As shown in FIG. 1, in this embodiment, the sub-coil 9 is arranged on the rear end side of the horizontal deflection coil 7 (FIG. 1A), so that the magnetic field ΦS by the sub-coil 9 (FIG. 1B) Are formed on the electron gun side of the main magnetic field ΦM (FIG. 1C) formed by the horizontal deflection coil 7 so as to reduce the main magnetic field ΦM.

Thus, the deflection magnetic field applied to the cathode ray tube is represented by a combined magnetic field .PHI.T obtained by combining the two magnetic fields .PHI.M and .PHI.S (FIG. 1 (D)). A synthetic magnetic field ΦT is formed so as to be weak. Therefore, in this case, the deflection yoke 1 has the main magnetic field ΦM
The magnetic field center O2 of the composite magnetic field ΦT can be moved toward the display screen by an amount L which is smaller than the magnetic field center O1 of the main magnetic field ΦM on the electron gun side.

When a predetermined load is connected to the sub-coil 9 and the impedance of the load is modulated so as to decrease at the corner of the display screen and increase at the center of the display screen, the load is applied to the cathode ray tube. Synthetic magnetic field ΦT
Can be moved to the display screen side at the corner portion. As described above, if the magnetic field center O2 of the synthetic magnetic field ΦT can be moved toward the display screen at the corner, the deflection center can be moved toward the display screen at the corner, and the margin of the corner with respect to the neck shadow is correspondingly increased. The degree can be improved. Therefore, the deflection sensitivity can be improved, and the whole can be reduced in size and weight.

As shown in FIG. 4, in this embodiment, a saturable reactor 10 is used as a load circuit for the sub coil 9 in this embodiment.
And saturable reactor 10 is connected to vertical deflection current IV.
Modulate with That is, the horizontal deflection coils 7 are connected in parallel and driven by the horizontal deflection current IH. The saturable reactor 10 is formed by winding a primary winding and a secondary winding on a prescribed magnetic circuit, and is connected in parallel with the vertical deflection coil 8.
And the primary winding are connected in series, and the secondary winding is connected to the sub-coil 9 connected in series.

Further, in the saturable reactor 10, the magnetic circuit is selected so as to saturate when the vertical deflection current IV increases and deflects near the upper and lower ends of the display screen. As a result, the impedance of the saturable reactor 10 decreases in the vicinity of the upper and lower ends of the display screen, and a magnetic field due to the back electromotive force is generated due to the reduction of the impedance to bring the magnetic circuit closer to saturation. The impedance changes so that the current of the sub coil 9 increases near the end.

Therefore, in the deflection yoke 1, the deflection center can be moved toward the display screen near the upper and lower ends,
As a result, the margin for the neck shadow near the upper and lower ends can be improved. The saturable reactor 10 is arranged on a terminal board for relay connection between the horizontal deflection coil 7 and the vertical deflection coil 8 and the set substrate, and is connected to the horizontal deflection coil 7 and the vertical deflection coil 8. ing.

Thus, in the deflection yoke 1, the horizontal deflection coil 7 and the vertical deflection coil 8 are deflected so that the original deflection center moves to the electron gun side by the increased margin near the upper and lower ends with respect to the neck shadow. By moving the positions of the display screen and the end face of the yoke 1 toward the electron gun, the overall length is reduced. Along with this, the components such as the separator and the front cover 5 are also
The overall length is designed to be short or small. As a result, the deflection yoke 1 has an increased margin near the upper and lower ends with respect to the neck shadow, so that the deflection sensitivity is improved, and the size and weight are reduced.

On the other hand, in this embodiment, the change in the magnetic field strength of the entire deflecting magnetic field before and after the saturable reactor 10 saturates is observed. The change in the magnetic field strength becomes smaller with respect to the change in the current. That is, in the deflection yoke 1, the change in the magnetic field intensity is smaller in the vicinity of the upper and lower ends than in the other portions with respect to the change in the deflection current.

Considering this and the fact that the center of deflection moves to the display screen side, the deflection yoke 1 has a raster-shaped barrel shape as compared with the conventional deflection yoke. Become. On the other hand, in the conventional deflection yoke, pin distortion cannot be avoided, and therefore, a pin distortion correction mechanism such as a pin distortion correction magnet is provided. Thus, according to the deflection yoke 1 of this embodiment, it is understood that the pin distortion can be reduced. According to the results of the experiment, it was confirmed that the pin distortion can be completely neglected depending on the driving conditions for the left and right pin distortion.

In the above arrangement, the deflection magnetic field formed by the horizontal deflection coil 7 and the vertical deflection coil 8 crosses the tube axis of the cathode ray tube up and down and left and right, and then turns around the core 4 substantially half a turn. Returning to the horizontal deflection coil 7 and the vertical deflection coil 8, when the polarity of the deflection current is reversed, it follows the reverse path. This deflection magnetic field changes following the change of the deflection current, so that the deflection yoke 1
The electron beam emitted from the electron gun is electromagnetically deflected.

At this time, the deflection yoke 1 can be constituted by a load circuit of the sub coil 9 in the vicinity of the upper and lower ends of the display screen due to the back electromotive voltage induced in the sub coil 9 by the horizontal deflection magnetic field and by the vertical deflection current IV. When the saturation reactor 10 is saturated, near the upper and lower ends,
A current flows through the sub-coil 9, and a magnetic field ΦS is formed by the sub-coil 9 so that the main magnetic field ΦM formed by the horizontal deflection coil 7 is reduced on the electron gun side (FIG. 1).

As a result, in the horizontal deflection magnetic field applied to the cathode ray tube, the main magnetic field .PHI.M formed by the horizontal deflection coil 7 is applied as it is near the center of the display screen, whereas it is applied near the upper and lower ends. Is the sub coil 9
And a main magnetic field .PHI.M are applied. The combined magnetic field ΦT is generated by the magnetic field ФS formed by the induced voltage of the sub-coil 9 so that the main magnetic field ΦM formed by the horizontal deflection coil 7 is reduced on the electron gun side.
As a result, the deflection center moves to the display screen side as compared with the case where only the main magnetic field ΦM is used.

That is, in the deflection yoke 1, near the upper and lower ends, a magnetic field is formed by the sub-coil 9 so that the center of deflection moves to the display screen side. Thus, the deflection sensitivity can be increased, and the size and weight can be reduced.

According to the above configuration, the sub-coil is arranged on the electron gun side of the horizontal deflection coil so as to correspond to the horizontal deflection coil so as to be induced by the horizontal deflection magnetic field. By forming a magnetic field with the sub-coil 9 so that the deflection center moves to the display screen side by effectively using the voltage, the deflection center can be moved to the display screen side near the upper and lower ends, and the neck is accordingly reduced. It is possible to increase the margin near the upper and lower ends with respect to the shadow.
Thus, in this embodiment, neck shadows near the upper and lower ends can be effectively avoided, the deflection sensitivity can be increased accordingly, and the overall shape can be reduced in size.

In the above embodiment, the case where the sub-coils 9 are connected in series and then connected to the saturable reactor 10 has been described. However, the present invention is not limited to this, and two saturable reactors 10 are prepared. Alternatively, each saturable reactor 10 may be individually connected to the sub coil 9.

Further, in the above-described embodiment, the saturable reactor 10 is used as a load circuit of the sub-coil 9, and the saturable reactor 10 is driven by the vertical deflection current IV. Although the case where the magnetic field ΦS is reduced near the end to form the magnetic field ΦS has been described, the present invention is not limited to this case. In addition, various load circuits can be widely applied.

In the above-described embodiment, the case where the sub-coil is formed by the self-bonding wire has been described. However, the present invention is not limited to this, and when the sub-coil is formed by winding using a bobbin or the like, a separateer is used. Various coil forming methods can be widely applied, for example, when forming by direct winding.

Further, in the above embodiment, the case where both the horizontal deflection coil and the vertical deflection coil are formed in a saddle shape by section winding has been described, but the present invention is not limited to this, and the vertical deflection coil is toroidally wound. In some cases, the present invention can be widely applied to various types of deflection yokes.

[0043]

As described above, according to the present invention, a sub-coil is arranged on the electron gun side of the horizontal deflection coil so as to correspond to the horizontal deflection coil, and the sub-coil is induced near the upper and lower ends of the display screen. By reducing the electron gun-side magnetic field of the horizontal deflection magnetic field by the back electromotive force, the deflection center can be moved to the display screen near the upper and lower ends. As a result, it is possible to increase the margin near the upper and lower ends of the neck shadow, thereby effectively avoiding the neck shadow, increasing the deflection sensitivity, and reducing the overall shape.

[Brief description of the drawings]

FIG. 1 shows a deflection yoke according to an embodiment of the present invention.
It is an approximate line figure used for explanation of movement of a deflection center.

FIG. 2 is a side view showing the overall configuration of the deflection yoke of FIG.

FIG. 3 is a perspective view showing a relationship between a horizontal deflection coil and a sub coil in the deflection yoke of FIG. 2;

FIG. 4 is a connection diagram showing connection of sub-coils in the deflection yoke of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Deflection yoke 4 Core 7 Horizontal deflection coil 8 Vertical deflection coil 9 Subcoil 10 Saturable reactor

Claims (2)

(57) [Claims] 1. A deflection yoke held by a neck of a cathode ray tube and electromagnetically deflecting the cathode ray tube, the deflection yoke being opposed to each other with the neck of the cathode ray tube interposed therebetween and forming a horizontal deflection magnetic field. A horizontal deflection coil, a sub-coil disposed on the electron gun side of the cathode ray tube so as to correspond to the horizontal deflection coil, and induced by the horizontal deflection magnetic field to generate a counter electromotive voltage; and a display of the cathode ray tube. When deflecting near the top and bottom edges of the screen,
And a load circuit for the sub-coil whose impedance is reduced. 2. The load circuit is formed of a saturable reactor having a primary winding and a secondary winding, supplies a vertical deflection current to the primary winding, and connects the secondary winding to the sub coil. The deflection yoke according to claim 1, wherein the deflection yoke is connected.