JPH08129975A - Deflection yoke - Google Patents

Abstract

PURPOSE: To provide a deflection yoke by which a neck shadow of a corner part is effectively avoided and deflecting sensitivity can be improved better than usual and whose shape can be downsized. CONSTITUTION: A sub-coil 9 is arranged on the electron gun side of a horizontal deflection coil 7 so as to be opposed to the horizontal deflection coil 7. A magnetic field ΦS is formed in the vicinity of the upper and lower ends of a display image screen so that an electron gun side magnetic field of a horizontal deflecting magnetic field ΦM is reduced by counter electromotive voltage induced in this sub-coil 9.

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 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, a deflection center is set in a cathode ray tube device so that a neck shadow is not generated, and the entire length is substantially determined by the deflection center.

That is, in this type of deflection yoke, a pair of horizontal deflection coils is arranged above and below so as to sandwich the neck of the cathode ray tube, and a horizontal deflection magnetic field which vertically traverses the neck of the cathode ray tube is formed by the pair of horizontal deflection coils. It is formed. Further, the deflection yoke has a pair of left and right vertical deflection coils arranged from the outside of the horizontal deflection coil so as to sandwich the neck of the cathode ray tube, and the pair of vertical deflection coils vertically deflects the vertical deflection across the neck of the cathode ray tube. A magnetic field is created.

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

As a result, in the cathode ray tube device, the horizontal deflection coil and the vertical deflection coil are driven to electromagnetically deflect the electron beam emitted from the electron gun and raster scan the electron beam. That is, the electron beam emitted from the electron gun, when passing through the deflection magnetic field, is deflected by deflecting the scanning locus to the up, down, left and right of the cathode ray tube, and then travels straight toward the front surface of the funnel portion of the cathode ray tube.

Therefore, in the cathode ray tube device, if the deflection center (ie, the center of the magnetic field distribution of the deflection magnetic field) is set too close to the electron gun side, the electron beam emitted toward the corner portion of the display screen will be In the middle of running,
This collides with the inner wall surface of the neck, which obstructs the travel of the electron beam at the corner and causes a neck shadow.

Therefore, in the deflection yoke, the length of the deflection coil is extended to the front side of the cathode ray tube as compared with the length of the neck of the cathode ray tube, so that the deflection center is located above the specified position and to the front side of the cathode ray tube. It is designed to effectively avoid the neck shadow.

[0008]

When the deflection center is set on the front side of the cathode ray tube as described above, it is necessary to increase the deflection angle by that amount, 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 correspondingly, the deflection magnetic field can be reduced to reduce power consumption, and the temperature rise of the deflection yoke can be reduced. it can.

With this as a premise, focusing on the central portion of the display screen of the cathode ray tube device, in the central portion of the display screen, even if the deflection center is shifted to the electron gun side, the neck shadow does not occur. . Therefore, in the deflection yoke, if it is possible to effectively avoid only the neck shadow in the corner portion, the deflection center can be arranged so as to be shifted toward 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 portion, so that the front end diameter of the deflection yoke needs to be increased accordingly. Therefore, in the deflection yoke, if the deflection center can be displaced to the electron gun side, the overall shape can be downsized and the weight can be reduced accordingly.

The present invention has been made in consideration of the above points, and effectively avoids the neck shadow at the corner portion,
The present invention intends to propose a deflection yoke which can improve the deflection sensitivity and can be downsized in comparison with the conventional one.

[0012]

In order to solve the above problems, in the present invention, the cathode ray tube is held by the neck,
In a deflection yoke that electromagnetically deflects a cathode ray tube, a pair of horizontal deflection coils that are held so as to face each other with a neck of the cathode ray tube interposed therebetween and form a horizontal deflection magnetic field, and horizontal deflection is performed on the electron gun side of the cathode ray tube. The sub-coil is arranged so as to correspond to the coil and generates a back electromotive force induced by the horizontal deflection magnetic field, and the load circuit of the sub-coil whose impedance decreases when deflecting near the upper and lower ends of the display screen of the cathode ray tube. To prepare.

Further, the load circuit includes a primary winding and a secondary winding.
It is formed of a saturable reactor with a secondary winding, which supplies a vertical deflection current to this primary winding and connects this secondary winding to said subcoil.

[0014]

When a sub-coil that is arranged so as to correspond to the horizontal deflection coil and that generates a counter electromotive voltage is induced by the horizontal deflection magnetic field and that the vicinity of the upper and lower ends of the display screen of the cathode ray tube is deflected with respect to this sub-coil By connecting a load circuit whose impedance decreases, a magnetic field is generated in the sub-coil in the direction of canceling the horizontal deflection magnetic field when deflecting the vicinity of 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.

Particularly, if the load circuit is formed by a saturable reactor having a primary winding and a secondary winding, the saturable reactor is set to saturate when the vertical deflection current increases,
When deflecting near the upper and lower ends of the display screen, a magnetic field can be generated in a direction that cancels the horizontal deflection magnetic field.

[0016]

Embodiments of the present invention will be described in detail below 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. Figure 2
In the cross section side, only the horizontal deflection coil 7 and the like are described, and the description of other components is omitted. Here, in the assembly process of the deflection yoke 1, 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.

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

The vertical deflection coil assembly 3 is formed by winding the vertical deflection coil 8 around a separator forming a coil bobbin in a vertical winding process. Here, the vertical deflection coil 8 is formed in a saddle shape by section winding, and when the deflection yoke 1 is arranged on the cathode ray tube, the neck of the cathode ray tube is sandwiched from the left and right sides of the horizontal deflection coil assembly 2 and the core. It is arranged on the inside of 4. As a result, the vertical deflection coil 8 forms a vertical deflection magnetic field that laterally crosses the neck of the cathode ray tube.

On the other hand, the horizontal deflection coil assembly 2 is formed by winding the horizontal deflection coil 7 around the separator forming the coil bobbin in the horizontal winding process. At this time, the horizontal deflection coil 7 is formed into a saddle shape by section winding by winding a specified magnet wire using the inner side surface of the separator and the protrusions formed on the front end surface and the rear end surface. The horizontal deflection coil 7 is
When the deflection yoke 1 is placed in the cathode ray tube, it is placed inside the vertical deflection coil assembly 3 so that the neck of the cathode ray tube is sandwiched from above and below. As a result, the horizontal deflection coil 7 forms a horizontal deflection magnetic field that vertically traverses the neck of the cathode ray tube.

Further, as shown in FIG. 3, in this embodiment, the horizontal deflection coil assembly 2 is provided on the electron gun side,
A sub-coil 9 is arranged, and in the deflection yoke 1, the center of deflection is moved to the display screen side by the sub-coil 9 near the upper and lower ends of the display screen. In FIG. 3, the horizontal deflection coil formed by section winding is simply shown.

Here, the sub-coil 9 has a circular arc shape along the neck of the cathode ray tube by winding a magnet wire made of a self-bonding wire on a predetermined mold and then self-bonding the wire, 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 recess is formed on the outer side surface of the separator, and after positioning the sub coil 9 using this recess,
Fix it to the separator with tape. As a result, the horizontal deflection coil assembly 2 can easily and reliably mount the sub-coil 9.

At this time, the horizontal deflection coil assembly 2
Holds the two sub-coils 9 so as to face each other with the neck of the cathode ray tube interposed therebetween so as to correspond to the horizontal deflection coil 7 held so as to face each other. As a result, 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.

By arranging the sub-coils 9 so that the horizontal deflection magnetic fields intersect with each other in this way, in the sub-coils 9,
A counter electromotive voltage is generated which is induced by the horizontal deflection magnetic field and suppresses the horizontal deflection magnetic field. In this case, the sub coil 9
If the terminals at both ends are opened and held, in the sub-coil 9, the counter electromotive voltage is simply maintained.
The horizontal deflection magnetic field is held in the magnetic field distribution formed by the horizontal deflection coil 7.

On the other hand, if both terminals of the sub-coil 9 are short-circuited, a current will flow in the sub-coil 9 due to the back electromotive force,
As a result, a magnetic field is formed by the sub-coil 9 in the direction of canceling the horizontal deflection magnetic field. As shown in FIG. 1, in this embodiment, by arranging the sub-coil 9 on the rear end side of the horizontal deflection coil 7 (FIG. 1 (A)), the magnetic field ΦS generated by the sub-coil 9 (FIG. 1 (B)). Is 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.

As a result, the deflection magnetic field applied to the cathode ray tube is represented by a synthetic magnetic field ΦT obtained by synthesizing these two magnetic fields ΦM and ΦS (FIG. 1 (D)). In this case, the main magnetic field ΦM is on the electron gun side. The 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 combined magnetic field ΦT can be moved to the display screen side by the amount L of the main magnetic field ΦM weakened on the electron gun side in comparison with the magnetic field center O1.

Thus, if a predetermined load is connected to the sub-coil 9 and the impedance of this load is modulated so that it becomes smaller at the corners of the display screen and becomes higher at the center of the display screen, it is applied to the cathode ray tube. Synthetic magnetic field ΦT
The magnetic field center O2 of can be moved to the display screen side at the corner portion. Thus, if the magnetic field center O2 of the composite magnetic field ΦT can be moved to the display screen side at the corner portion, the deflection center can be moved to the display screen side at the corner portion, and the margin of the corner portion with respect to the neck shadow is correspondingly increased. The degree can be improved. Therefore, the deflection sensitivity can be improved, and the overall size and weight can be reduced.

As shown in FIG. 4, therefore, in this embodiment, the saturable reactor 10 is used as the load circuit of the subcoil 9.
The saturable reactor 10 and the 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 around a specified magnetic circuit, and the vertical deflection coil 8 connected in parallel.
This primary winding is connected in series, and the secondary winding is connected to the sub-coils 9 connected in series.

Further, in the saturable reactor 10, the magnetic circuit is selected so as to be saturated when the vertical deflection current IV is increased and the vicinity of the upper and lower ends of the display screen is deflected. As a result, the saturable reactor 10 has a lower impedance near the upper and lower ends of the display screen, and a magnetic field due to a back electromotive force is generated due to this lowering 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 to the display screen side near the upper and lower ends,
This can improve the margin for the neck shadow near the upper and lower ends. The saturable reactor 10 is arranged on a terminal plate for connection relay 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 is moved to the electron gun side by the amount of increase in the margin near the upper and lower ends with respect to the neck shadow. By moving the positions of the display screen side and the end surface of the yoke 1 to the electron gun side, the entire length is shortened. Along with this, components such as the separator and the front cover 5 are also
The entire length is short or small. As a result, in the deflection yoke 1, the degree of margin near the upper and lower ends with respect to the neck shadow is increased, so that the deflection sensitivity is improved, and the size and weight are reduced.

By the way, on this implementation side, when the change in the magnetic field strength of the entire deflection magnetic field is observed before the saturable reactor 10 is saturated and after it is saturated, the deflection becomes greater after the saturation occurs than before the saturation. The change in magnetic field strength decreases with the change in current. That is, in this deflection yoke 1, the change in the magnetic field strength in the vicinity of the upper and lower ends is smaller than the change in the other portions, with respect to the change in the deflection current.

Considering this together with the fact that the deflection center moves to the display screen side, in this deflection yoke 1, the raster shape is formed in a barrel shape as compared with the conventional deflection yoke. Become. On the other hand, in the conventional deflection yoke, the occurrence of pin distortion cannot be avoided, and therefore a pin distortion correction mechanism such as a pin distortion correction magnet is provided. This shows that the deflection yoke 1 of this embodiment can also reduce this pin distortion. According to the result of the experiment, it was confirmed that the left and right pin distortion could be completely ignored depending on the driving condition.

In the above-mentioned structure, the deflection magnetic field formed by the horizontal deflection coil 7 and the vertical deflection coil 8 traverses the tube axis of the cathode ray tube up and down and left and right, respectively, and then turns around the core 4 for about half a turn to return to the original state. Returning to the horizontal deflection coil 7 and the vertical deflection coil 8, when the polarity of the deflection current is reversed, the reverse path is followed. This deflection magnetic field changes in accordance with the change in the deflection current, so that in the deflection yoke 1,
Electron deflection of the electron beam emitted from the electron gun.

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

Thus, in the horizontal deflection magnetic field applied to the cathode ray tube, the main magnetic field ΦM formed by the horizontal deflection coil 7 is applied as it is in the vicinity of the center of the display screen, whereas in the vicinity of the upper and lower ends. Is the subcoil 9
A combined magnetic field ΦT of the magnetic field ΦS of the magnetic field ΦS and the main magnetic field ΦM is applied. This combined magnetic field ΦT is formed by the induced voltage of the sub-coil 9 so as to reduce the main magnetic field ΦM formed by the horizontal deflection coil 7 on the electron gun side.
After all, the deflection center moves to the display screen side as compared with the case of only the main magnetic field ΦM.

That is, in the deflection yoke 1, the magnetic field is formed by the sub-coil 9 so that the deflection center moves toward the display screen near the upper and lower ends, and the margin for the neck shadow is correspondingly increased near the upper and lower ends. It is possible to improve, increase the deflection sensitivity, and reduce the size and weight.

According to the above structure, the sub-coil is arranged on the electron gun side of the horizontal deflection coil so as to be induced by the horizontal deflection magnetic field so as to correspond to the horizontal deflection coil, and the counter-electromotive force induced in the sub-coil is generated. By effectively utilizing the voltage, the deflection coil can be moved to the display screen side in the vicinity of the upper and lower ends by forming a magnetic field with the sub-coil 9 so that the deflection center is moved to the display screen side. The margin near the upper and lower ends of the shadow can be increased.
As a result, 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 made smaller.

In the above embodiment, the case where the sub-coil 9 is connected in series and then connected to the saturable reactor 10 has been described, but the present invention is not limited to this, and two saturable reactors 10 are prepared. , 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 the load circuit of the sub-coil 9, and the saturable reactor 10 is driven by the vertical deflection current IV, so that the load of the sub-coil 9 rises and falls above and below the display screen. Although the case where the magnetic field ΦS is formed by the reduction in the vicinity of the edge has been described, the present invention is not limited to this, and the point is that the load circuit of the sub-coil 9 may be set so that the impedance decreases at the corner of the display screen. Various load circuits can be widely applied.

In the above 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 separator is used. Various coil forming methods can be widely applied, such as the case of directly winding and forming.

Further, in the above-mentioned embodiment, the case where both the horizontal deflection coil and the vertical deflection coil are formed in the saddle type by section winding has been described, but the present invention is not limited to this, and the vertical deflection coil is toroidally wound. It can be widely applied to various forms of deflection yokes.

[0043]

As described above, according to the present invention, the 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 counter electromotive voltage, the deflection center can be moved to the display screen side near the upper and lower ends. As a result, it is possible to increase the margin in the vicinity of the upper and lower ends with respect to the neck shadow, effectively avoid the neck shadow, increase deflection sensitivity, and reduce the overall shape.

[Brief description of drawings]

FIG. 1 shows a deflection yoke according to an embodiment of the present invention.
FIG. 7 is a schematic diagram used to describe a movement of a deflection center.

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

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

FIG. 4 is a connection diagram showing the connection of sub-coils for the deflection yoke of FIG.

[Explanation of symbols]

 1 deflection yoke 4 core 7 horizontal deflection coil 8 vertical deflection coil 9 sub-coil 10 saturable reactor

Claims (2)

[Claims] 1. A pair of deflection yokes, which are held by a neck of a cathode ray tube and electromagnetically deflect the cathode ray tube, are held so as to face each other with the neck of the cathode ray tube interposed therebetween to form a horizontal deflection magnetic field. A horizontal deflection coil, a subcoil disposed on the electron gun side of the cathode ray tube so as to correspond to the horizontal deflection coil, and generating a counter electromotive voltage induced by the horizontal deflection magnetic field; and a display for the cathode ray tube. When deflecting near the upper and lower edges of the screen,
A deflection yoke, comprising: a load circuit of the sub-coil having a reduced impedance. 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 subcoil. The deflection yoke according to claim 1, wherein the deflection yoke is connected.