JP3211298B2 - 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 used for a television receiver or the like.

[0002]

2. Description of the Related Art At present, there is the following cathode ray tube for a display which requires a still image of a television screen. FIG. 8A is a diagram illustrating a schematic configuration of a cathode ray tube for a display, and FIG. 8B is a diagram illustrating an electron beam emitting unit of the cathode ray tube. That is, as shown in FIG. 8, the three electron beams emitted from the cathode 1 travel in parallel, but since the prefocus lens 2 is formed between the second grid and the third grid, the center beam 5
Is slightly focused. But both side beams 6,7
Are focused and turn slightly, crossing each other near the center of the fourth grid. Then, the focus is strongly focused by the main focus lens 3, and a sharp spot is formed on the phosphor screen.

[0003] The three electron beams that have passed through the main focus lens 3 diverge radially as they are, so they are bent inward again at the convergence electrode 4 and intersect on the aperture grill surface to form a central beam. 5 and both side beams 6 and 7 respectively emit different green, blue and red phosphors. This has the advantage that convergence correction is simplified, in addition to improving the screen resolution.

As shown in FIG. 9, a convergence electrode 4
Has four vertical deflecting plates 9, 10, 11 and 12, the inner two deflecting plates 10 and 11 are integrally formed, and these deflecting plates 10 and 11 lower the anode voltage by the internal carbon. The resulting relatively low voltage is applied. The two outer deflection plates 9 and 12 are also connected to each other in the tube, and the convergence can be adjusted by applying a voltage for correction thereto.

FIG. 10 shows the electric field generated by the convergence deflecting plate and the moving direction of the beam. Arrow 13 indicates the direction of the electric field, and arrow 14 indicates the direction of the force that the electron beams 6 and 7 receive.

Each deflecting plate 9, 1 of the convergence deflecting plate
A DC voltage lower than the anode voltage is applied to 0, 11, and 12, and when three electron beams pass between the respective deflection plates, the following occurs. That is, the center beam 5 travels straight through the area of the potential gradient 0, but the side beams 6, 7
Since the outside potential is low, the outside is bent inward and convergence is achieved.

However, the convergence deflector is made of metal, and the position of the convergence deflector is a position for receiving the magnetic field of the deflection yoke attached to the neck portion due to the absolute size restriction of the cathode ray tube. An eddy current is generated in the convergence deflection plate by a magnetic field generated by the yoke. Then, the convergence deflection plate generates heat due to the eddy current, and the heat may cause the convergence deflection plate to be thermally deformed. A portion of the convergence deflector shown in FIG. 9 through which the center beam 5 passes, that is, a portion having a U-shape is hardly deformed.
A portion through which the side beams 6 and 7 pass, that is, an L-shaped portion undergoes thermal deformation particularly at the bottom of the L-shape.

The thermal deformation and the convergence of the L-shaped portion will be described below. For example, as shown in FIG. 11, it is assumed that the electron beam originally has to be at the positions indicated by 17 and 18, but is at the positions indicated by 15 and 16 due to, for example, manufacturing variations of the electron gun. Then, the electron beam originally deviates from the trajectory to be taken, and the beam spot does not reach the original position, resulting in under-convergence among misconvergence.

This phenomenon has the same result as the retreat of the electron gun in principle, and the amount of underconvergence increases from the center of the screen to the periphery of the screen.

In such a case, an electric field is applied by the convergence electrode 4 to deflect the electron beam by an appropriate amount so that the electron beam comes to appropriate positions 17 and 18. This is the role of the convergence electrode 4.

On the other hand, the deflection yoke uses a self-convergence method. In the self-convergence method, misconvergence is basically not generated on the entire television screen only by the deflection current.

[0012]

However, the deflecting magnetic field emitted from the deflecting yoke generates an eddy current in the convergence deflecting plate. For example, as shown in FIG. 12, the L-shaped convergence deflecting plate extends by H1 and H2. Suppose. Then, the intensity of the electric field applied to the convergence deflection plate is reduced correspondingly, so that the position of the electron beam becomes 1
It moves to the positions 9 and 20 and again causes misconvergence.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a deflection yoke capable of eliminating an error, that is, a misconvergence on a phosphor screen caused by a temporal change of a cathode ray tube.

[0014]

In order to achieve the above object, a deflection yoke according to the present invention comprises a correction coil for generating a multipolar magnetic field by passing a horizontal deflection current. A coil for controlling the current of the CRT is wound, and a magnetic field of the correction coil is generated in a direction in which a magnetic flux of a permanent magnet is further applied to the magnetic material to cancel a misconvergence due to a temperature change caused by a temporal change of the cathode ray tube. And the magnetic material is a substance having a temperature characteristic over time.

[0015]

According to the present invention, a coil is wound on a magnetic material having a temperature characteristic over time, and a magnetic flux is applied to the coil by the magnet, whereby the inductance of the coil wound on the magnetic material is changed according to the temperature. changes Te, the deflection yoke electron gun side of the convergence polarized due to change in the inductance
Correction coil drive that generates a multipole magnetic field installed near the facing plate
The magnetic field generated by parts are changed, by force Koh at the cathode-ray tube
Correction co due to temperature changes of the misconvergence and the deflection yoke side of the magnetic body that occurs in the temperature change of Nbazensu deflector
Misconvergence generated by the drive unit cancels out, and consequently convergence without temperature change can be obtained.

[0016]

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

FIG. 1 is a wiring diagram of a deflection yoke according to the present invention. In FIG. 1, 21 and 22 are horizontal deflection coils,
Reference numeral 23 denotes a coil control unit for taking measures against temperature drift, and reference numerals 25 and 26 denote correction coil driving units for taking measures against temperature drift.

The correction coil drive unit 25 includes a sub coil 25
a, 25b, 25c, and 25d. The correction coil driving unit 25 and the coil 23 of the coil control unit 23
a and the horizontal deflection coil 21 are connected in series, a horizontal deflection current flows to the correction coil drive unit 25, and the magnitude thereof can be controlled by the coil control unit 23.
The correction coil driving section 26 is also composed of sub-coils 26a, 26b, 26c and 26d in the same manner as described above, and the correction coil driving section 26, the coil 23b of the coil control section 23 and the horizontal deflection coil 22 are connected in series. Then, a horizontal deflection current flows through the correction coil drive unit 26, and the magnitude thereof can be controlled by the coil control unit 23.

FIG. 2 is a diagram specifically showing the configuration of the coil control unit 23. As shown in FIG. Numerals 27 and 28 denote magnetic materials having time-dependent temperature characteristics. The coil 23b is wound around the magnetic material 27, and the coil 23a is wound around the magnetic material 28. The magnetic flux is applied to the magnetic bodies 27 and 28 by the magnet 31. FIG. 3 shows the temperature characteristics of the magnetic bodies 27 and 28 having the temperature characteristics over time.

That is, an electric wire is wound around two magnetic members 27 and 28 having the temperature characteristics shown in FIG.
Since the coils 23a and 23b are connected to each other, when a horizontal deflection current flows through them, the current flowing through the electric wires generates heat in the coils 23a and 23b, and the temperatures of the magnetic bodies 27 and 28 increase, and the inductance increases accordingly.

However, since the magnet 31 is attached to the control unit 23 of the coil for preventing temperature drift, a magnetic bias is applied to the two magnetic members 27 and 28.

Next, the operation of the biased coil controller 23 will be described. Two magnetic bodies 27, 2
In FIG. 8, the electric wire is wound around six turns so as to obtain an inductance of 6 μH, and the directions of the windings are the same as the directions 33 and 34 of the magnetic fluxes generated by the windings as shown in FIG.
(The reverse direction in the series magnetic circuit of FIG.
Direction) .

In FIGS. 4A and 4B, 35 and 3
Reference numeral 6 denotes the direction of the magnetic flux generated by the magnet 31, and the polarity thereof is as follows. That is, when the horizontal deflection current is positive as shown in FIG. 4A, a magnetic flux is applied to the coil 23a in the same direction 35 as the magnetic flux direction 34 generated by the coil 23a, and the coil 23b is applied to the other coil 23b. The polarity of the magnet 31 is set so that a magnetic flux is applied in the direction 36 opposite to the direction 33 of the magnetic flux in which the magnetic field is generated.

When the horizontal deflection current is positive, the coil 23
The inductance of a increases as the current increases, and the inductance of the coil 23b decreases on the contrary. On the other hand, when the horizontal deflection current is negative, the inductance of the coil 23a decreases as the current increases, and the coil 23b
Has a higher inductance.

From the above results, as shown in FIG. 4A, when the horizontal deflection current is positive, the current mainly flows to the correction coil driving section 26 connected to the coil 23b in FIG.
Further, as shown in FIG. 4B, when the horizontal deflection current is negative, the inductance of the coil 23a decreases as the current increases, and the inductance of the coil 23b increases on the contrary. Flows.

FIG. 5 is a diagram for explaining the movement of electron beams in the CRTs 25 and 26 and the CRT. In other words, if the convergence deflecting plate incorporated in the electron gun undergoes thermal deformation due to prolonged use, the electron beam is displaced as described above, resulting in under-convergence.

In order to compensate for the misconvergence, the correction coil drive units 25 and 2 must be used for a long time.
6 needs to be set to generate a magnetic field in the direction of overconvergence. For this correction coil driving unit 25, 26 generates a magnetic field in the direction of over-convergence, the correction coil driving unit 25,2
6 are connected in reverse to each other, and when the horizontal deflection current is positive,
Correction coil driving unit 25 makes the magnetic poles shown in FIG. 5, the correction U
When the horizontal deflection current is positive, the correction coil driving unit
The coil control unit 23 is adjusted so that a large amount of current flows to the correction coil driving unit 25 when a large amount of current flows to the correction coil driving unit 25 when the horizontal deflection current is negative. At this time, FIG.
The two magnetic bodies 27 and 28 having the temperature characteristics shown
As the inductance increases with the rise,
Attempts to adjust horizontal deflection current by drive units 25 and 26
Effect is further emphasized by the rise in temperature.
You.

With this arrangement, as shown in FIG. 5, the side electron beam is easily pulled inward and is likely to be over-converged. , 7 are
It is slightly deflected by the force in the directions of arrows 39 and 40.

This will be described more specifically. As described above, the correction coil driving unit 25 includes the sub coils 25a, 25b, 25
c, 25d, and the correction coil drive unit 26 is composed of sub-coils 26a, 26b, 26c, 26d. These sub-coils 25a to 26d are described later.
The convergence deflection plate is formed as shown in FIG.
Near the convergence deflector to offset temperature changes
Placed in

As shown in FIG. 7, the sub-coil 25a and the sub-coil 26a are wound by a bi-filer. For example, when the horizontal deflection current is positive, a current flows from the winding start side 41 to the coil of the sub-coil 25a. In
It is preferable to supply a current from the winding end 42.

Similarly, four bifilar sub-coils are formed, for example, a sub-coil 25a and a sub-coil 2
5b are connected in series, the sub-coil 25c and the sub-coil 25d are connected in series, these are connected in parallel, and this is connected in series to the coil 23a of the coil control unit. At the same time, the sub coil 26a and the sub coil 26b are connected in series, the sub coil 26c and the sub coil 26d are connected in series and connected in parallel with each other, and further connected to the coil 23b of the coil control unit. FIG. 6 is an external view of the coils of the four connected bi-filers.
That is, by connecting this to the coil control unit 23 and supplying a horizontal deflection current to them, a magnetic field as shown in FIG. 5 is generated and misconvergence can be reduced.

[0032]

As described above, the present invention provides a multi-pole structure in which a coil is wound around a magnetic material having a temperature characteristic over time, a magnetic flux is applied to the coil, and the magnetic flux is applied to the electron gun side of the deflection coil. By being connected to the correction coil that generates a magnetic field, the magnetic material changes over time, and the magnetic field generated by the correction coil acts to cancel misconvergence due to thermal deformation of the convergence deflecting plate. Misconvergence due to the convergence deflection plate can be reduced.

[Brief description of the drawings]

FIG. 1 is a wiring diagram of a deflection yoke according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a coil control unit in one embodiment.

FIG. 3 is a graph showing temperature characteristics of a control unit of a temperature drift countermeasure coil according to one embodiment.

FIG. 4A is an explanatory diagram showing the direction of magnetic flux when the horizontal deflection current of the control unit of the temperature drift countermeasure coil according to the embodiment is positive; FIG. 4B is the control unit of the temperature drift countermeasure coil according to the embodiment; Explanatory diagram showing the direction of magnetic flux when the horizontal deflection current is negative

FIG. 5 is an explanatory diagram for explaining a movement of an electron beam in a CRT and a correction coil driving unit;

FIG. 6 is an external perspective view of a correction coil driving unit.

FIG. 7 is a schematic configuration diagram of a temperature drift countermeasure coil.

FIG. 8A is a schematic configuration diagram of a display CRT; FIG. 8B is a schematic configuration diagram of an electron beam emitting unit of the CRT;

FIG. 9 is a schematic diagram of a convergence deflection plate of the CRT.

FIG. 10 is an explanatory diagram showing how an electric field is applied to a convergence deflection plate of the CRT and the movement of an electron beam.

FIG. 11 is an explanatory diagram for explaining a role of a convergence deflection plate of the CRT.

FIG. 12 is an explanatory diagram showing the movement of an electron beam when the convergence deflection plate of the cathode ray tube undergoes thermal deformation.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cathode 2 Prefocus lens 3 Main focus lens 4 Convergence electrode 9,10,11,12 Deflection plate 21,22 Horizontal deflection coil 23 Coil control unit 25,26 Correction coil drive unit

Claims (1)

(57) [Claims] 1. Three beams using a convergence deflection plate
Used for electron gun CRT , horizontal deflection coil and coil
An auxiliary coil drive composed of a control unit and multiple sub-coils
Same as the first series circuit configured by connecting the moving parts in series
And a second series circuit connected in series to the deflection yoke , wherein the coil control unit includes at least one magnet and a temperature characteristic.
A magnetic circuit composed of two magnetic bodies having
A first coil formed by winding the first series circuit around the magnetic material;
And the second series circuit wound around another magnetic body.
And a second coil, and the first series circuit
The current induced by the current in the first coil and the second direct current
The magnetic flux induced in the second coil by the current in the column circuit is
In the magnetic circuit, the first coil
And the second coil is wound around the magnetic body , and the magnetic body is wound around the magnetic body in accordance with an increase in temperature.
Inductance between the first coil and the second coil
Temperature characteristics of the magnetic material so that
And the auxiliary coil drive unit is controlled so that misconvergence due to thermal deformation of the convergence deflection plate is offset.
A deflection yoke characterized by being arranged near a convergence deflection plate .