JP3353338B2 - Convergence correction device - 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 combined with a cathode ray tube used for a television receiver or the like.
The present invention relates to a convergence correction device that modulates a horizontal deflection current with a vertical deflection current.

[0002]

2. Description of the Related Art FIG. 9 is a front view of a deflection yoke. In the figure, reference numeral 14 denotes an insulating frame, and reference numerals 1a and 1b denote saddle-type horizontal deflection coils mounted inside the insulating frame 14. Normally, the saddle type horizontal deflection coil is divided into upper and lower parts as shown in FIG. 9, and 1a is an upper coil arranged at an upper part and 1b is a lower coil arranged at a lower part. The horizontal deflection is performed by combining the magnetic field generated by the upper coil 1a and the magnetic field generated by the lower coil 1b. That is, the electron beam is optically bent at the magnetic center of the horizontal coil, which is called the deflection center of the horizontal coil.

However, in the deflection yoke configured as described above, the flatness of a conventional cathode ray tube face determined by a geometrical element becomes closer to a flat surface, and the cathode ray tube electron determined by an optical element. The planes deflected by the beam deflection yoke do not coincide with each other, that is, as shown in FIG. 10, the converging surface 15 of the electron beam does not coincide with the fluorescent screen 16 of the cathode ray tube, and misconvergence occurs on the screen surface of the cathode ray tube shown in FIG. Occurs.

[0004]

In order to eliminate this misconvergence, a magnetic material such as a ferrite sheet shown in FIG. 12 is attached to the surface of the horizontal deflection coil. When such a magnetic material is stuck, for example, as shown in the first quadrant on the surface of the CRT screen, the blue electron beam receives a force in the direction of the white arrow 6 when it swings to the upper right end as shown in FIG. At the upper right corner, the amount of deviation between the bright line 7 due to the blue electron beam and the bright line 8 due to the red electron beam is small. However, since the effect of the force of the white arrow 6 also occurs at the right middle end of the screen, the force exerts too much influence on this portion, resulting in misconvergence as shown in FIG. In other words, although the misconvergence amount decreases at the upper end of the screen, the tendency of the misconvergence is opposite at the center of the screen, but the amount does not decrease so much and there is no effect on the elimination of misconvergence as a whole.

[0005]

Means for Solving the Problems Vias are formed by permanent magnets.
Have two shaft cores made of a magnetic material to which a magnetic field is applied,
When the first coil and the third coil are wound around one shaft core,
Then, the second coil and the fourth coil are wound around the other axis,
Connect one coil and second coil to one horizontal deflection
Connected to the third coil and the fourth coil
Is connected to the other horizontal deflection coil, and the positive horizontal deflection current
The first carp wound around different shaft cores when flowing
Field and the second coil are the same as the above bias magnetic field
3rd coils wound around different shaft cores
Magnetic field by the coil and the fourth coil is in the opposite direction to the above bias magnetic field.
And a positive vertical deflection voltage is applied to the vertical deflection coil.
The via generated by this vertical deflection current when current flows
Magnetic field is the same as the magnetic field generated by the first and second coils
Direction, opposite to the magnetic field generated by the third and fourth coils
A convergence correction device is installed.

[0006]

According to the present invention, the horizontal deflection current is modulated by the vertical deflection current according to the above configuration. This modulation is performed as the vertical deflection current increases, that is, as the vertical amplitude increases, and the horizontal deflection current increases. The higher the horizontal amplitude, the greater the degree of modulation. In addition, since the effect is increased, in the deflection yoke configured as described above, the same effect can be obtained as when the deflection center moves on the horizontal axis of the CRT according to the horizontal deflection amplitude, and in the vertical direction. The same effect can be obtained as the deflection center moves on the vertical axis of the cathode ray tube according to the vertical deflection amplitude. As a result, the deflection surface of the deflection yoke becomes closer to the cathode ray tube face surface, and the converging surface of the electron beam. 4 coincides with the fluorescent screen 5 of the CRT.

[0007]

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

FIG. 1 is a circuit diagram of a deflection yoke provided with the convergence correction device of the present invention. Here, 1a is the upper coil of the horizontal coil, 1b is the lower coil of the horizontal coil, 2 is the vertical coil, 3 is the first coil, 4 is the second coil, 5 is the third coil, 6 is the fourth coil, 7 is a vertical auxiliary coil.

As apparent from FIG. 1, the horizontal coil 1a
, A first coil 3 and a second coil 4 are wired and connected in series, and a horizontal coil 1b is wired and connected in series with a third coil 5 and a fourth coil 6.

The vertical coil 2 includes a vertical auxiliary coil 7.
Are wired in series. FIG. 2 is a block diagram of the convergence correction device of the present invention, wherein 3 to 7 have the same names as in FIG. 1, except that 8 is a permanent magnet.

The first coil 3 and the third coil 5 are connected to one shaft core.
9 and the second coil 4 and the fourth coil 6
It is wound around 10 . And the vertical auxiliary coil 7 has a shaft core 11
It is wound around.

An N pole is applied to the shaft core 9 by a permanent magnet 8 at the left end, and an S pole is applied to the shaft core 10 at the left end thereof as a DC bias. At the right end of the shaft core 10, an alternating magnetic field generated by the vertical deflection current by the shaft core 11 of the vertical auxiliary coil 7 is applied .

The principle of the convergence correction device thus constructed will be described below with reference to FIG.

FIG. 3 is a diagram for explaining the CRT screen divided into four sections.
m, the magnetic bias generated by the current flowing through the upper coil of the horizontal deflection coil is ψa, and the magnetic bias generated by the current flowing through the lower coil of the horizontal deflection coil is ψ
b, Let the magnetic bias generated by the current flowing through the vertical deflection coil be Δv.

First, the first quadrant deflection is when the upper right of the cathode ray tube is deflected. The magnetic flux ψ9 generated in the shaft core 9 is generated from the permanent magnet side to the shaft center side of the vertical auxiliary coil. Assuming that the direction is positive, it is represented by the following (Equation 1).

[0016]

(Equation 1)

The magnetic flux ψ10 generated in the shaft core 10 is
It is represented by the following (Equation 2).

[0018]

(Equation 2)

In general, the bias of the permanent magnet is set to be the same as the maximum bias due to the vertical deflection current.
If m = ψv, (Equation 1) and (Equation 2) are as follows (Equation 3) and (Equation 4).

[0020]

(Equation 3)

[0021]

(Equation 4)

That is, the magnetic flux ψ9 generated in the shaft core 9 is generated only by the magnetic bias ψb generated by the current flowing in the coil below the horizontal deflection coil.

The magnetic flux ψ10 generated in the shaft core 10 is generated by a bias obtained by subtracting the sum of the magnetic bias generated by the permanent magnet and the vertical deflection current, that is, 2ψm, from the magnetic bias ψa generated by the current flowing in the coil above the horizontal deflection coil. Will be.

That is, in the shaft core 9, the magnetic bias increases as the horizontal deflection current flows, and the inductance generated in the shaft core 9 increases accordingly.

In the shaft core 10, the magnetic bias decreases as the horizontal deflection current flows, and accordingly, the inductance generated in the shaft core 10 decreases.

The above will be described with reference to FIG. FIG.
, The horizontal axis represents the magnetomotive force (current flowing through the shaft cores 9 and 10 × the number of turns), the vertical axis represents the inductance, the curve C represents the change in the inductance generated in the shaft core 9, and the curve D represents the change in the inductance of the shaft core 1.
It shows the change in inductance that occurs at zero. As is clear from this figure, the more the horizontal deflection current flows in the shaft cores 9 and 10, the larger the difference in inductance generated between the shaft cores 9 and 10 becomes. This indicates that there is a difference between the inductance acting on the current flowing on the upper side of the horizontal deflection coil and the inductance acting on the current flowing on the lower side of the horizontal deflection coil. Also, as shown in FIG. 4, as the horizontal size of the screen increases,
It is also necessary to increase the magnetomotive force (current flowing through the shaft cores 9, 10 x number of turns).

As is apparent from FIG. 4, this difference in inductance does not occur when the horizontal deflection current is zero, but as the horizontal deflection current gradually increases, the difference in inductance also increases. Does not occur even when is zero, but the difference in inductance also increases as the vertical deflection current gradually increases.

Similarly, in the second quadrant, the third quadrant, and the fourth quadrant, only the directions of the horizontal deflection current and the vertical deflection current are respectively as shown in FIG. Differences arise.

The effect of this difference in inductance on the television screen will be described below with reference to FIG.
In FIG. 5, 12B and 12R are lines of magnetic force generated by the horizontal deflection coil. As shown in FIG. 4, the current that produces a magnetic field in the shaft core 9 flows through the upper coil of the horizontal deflection coil, so that the inductance of the shaft core 9 increases with an increase in the current amount, and the current amount decreases. . On the contrary,
The amount of current flowing below the horizontal deflection coil increases.
This is the same as the case where the center of gravity of the coil on the upper side of the deflection coil moves in the Y-axis direction as shown in FIG. 5, and the center of gravity of the coil on the lower side of the deflection coil moves in the direction away from the Y-axis. It has the same effect as moving.

That is, the direction of the lines of magnetic force (12B, 12R) created by the horizontal deflection coil is the direction extending from top to bottom. In other words, the line of magnetic force 12R acting on the red electron beam is directed downward and to the right,
2B is directed to the lower left direction. Therefore, the force received by the electron beam is as follows.
The blue electron beam is directed in the direction 13B, the red electron beam R receives an upward force, and the blue electron beam B receives a downward force, so that the television screen has a convergence pattern shown in FIG.

And, as described above, this pattern
As the horizontal deflection current and the vertical deflection current increase, the actual TV screen becomes smaller at the center of the screen and greatly changes at the periphery of the screen as shown in FIG.

Therefore, the misconvergence pattern is opposite to the pattern described in FIG. 13 of the conventional example, so that a screen with little misconvergence is ultimately obtained.

The first coil 3 and the third coil 5 have opposite current directions, and the first coil 3 and the third coil 5 are wound around one shaft core 9 , and the second coil Since the current directions of the fourth coil 4 and the fourth coil 6 are opposite to each other, and the second coil 4 and the fourth coil 6 are wound around one shaft core 10 , the magnetic bias generated on the shaft cores 10 and 9 is There is no effect due to the increase or decrease of the horizontal deflection current. Therefore, due to the high resolution required for television screens in recent years, even if the horizontal deflection frequency is increased, there is no problem of heat generation due to the magnetic bias of the shaft cores 10 and 9.

In general, the CRT screen is spherical with respect to the vertical axis. Therefore, it was assumed that ψm = ψv, but there are cases where this is not necessary. At that time, as shown in FIG. 8, the permanent magnet may be a cylindrical magnet 14, and the magnetic bias may be varied by rotating the permanent magnet to obtain an optimum value.

[0035]

As described above, according to the present invention, the permanent magnet is used.
Cores made of magnetic material to which a bias magnetic field is applied
And the first coil and the third coil are wound around one axis.
And the second and fourth coils are wound around the other axis.
Turn and connect the first coil and the second coil
Connect to the horizontal deflection coil and connect the third coil and the fourth coil.
Connected to the other horizontal deflection coil,
Wound around different shaft cores when deflection current flows
The magnetic field generated by the first coil and the second coil is the bias magnetic field.
In the same direction as, and wound on different shaft cores
The magnetic field generated by the third coil and the fourth coil is the bias magnetic field.
And the direction perpendicular to the vertical deflection coil.
When vertical deflection current flows, it is generated by this vertical deflection current.
Bias magnetic field and the magnetic field generated by the first coil and the second coil
Same direction, opposite to the magnetic field generated by the third and fourth coils
By installing a convergence correction device arranged so that the horizontal deflection current is modulated by the vertical deflection current, this modulation is performed as the vertical deflection current increases, that is, as the vertical amplitude increases, and the horizontal deflection current increases. As the deflection current becomes larger, that is, as the horizontal amplitude becomes wider, the modulation is applied and the effect becomes larger. Therefore, in the deflection yoke thus configured, it is determined by the optical element. The plane deflected by the deflection yoke of the CRT electron beam is the point where the deflection is not performed. The center of the CRT, the vertical axis where the vertical deflection is performed, and the horizontal axis where the horizontal deflection is performed. It will be different, and also about the vertical plane from the center,
It will change as you go to the CRT screen edge,
The horizontal plane also changes from the center to the screen end of the cathode-ray tube. As a result, the deflection surface of the deflection yoke becomes closer to the face of the cathode-ray tube, and the converging surface of the electron beam coincides with the fluorescent surface of the cathode-ray tube. Become like The degree of modulation that modulates the horizontal deflection current with the vertical deflection current increases as the vertical deflection current increases, that is, as the vertical amplitude increases, and as the horizontal deflection current increases, that is, as the horizontal amplitude increases. The modulation is applied, so that the convergent surface of the electron beam and the phosphor screen of the cathode ray tube, which are not coincident with each other, are coincident with the flatness of the picture plane of the cathode ray tube, so that the misconvergence caused by this is also solved. .

[Brief description of the drawings]

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

FIG. 2 is a schematic diagram of a convergence correction device according to an embodiment of the present invention.

FIG. 3 is a diagram showing the operation of a convergence correction device according to an embodiment of the present invention.

FIG. 4 is a graph showing characteristics of the convergence correction device according to one embodiment of the present invention.

FIG. 5 is a diagram for explaining lines of magnetic force from a horizontal deflection coil generated by a convergence correction device according to one embodiment of the present invention.

6 is a diagram showing a misconvergence pattern generated by the lines of magnetic force generated in FIG.

FIG. 7 is a diagram showing a convergence pattern generated by a convergence correction device according to an embodiment of the present invention.

FIG. 8 is a schematic diagram of a convergence correction device according to a second embodiment of the present invention.

FIG. 9 is a front view of a deflection yoke.

FIG. 10 is a diagram for explaining a converging surface of an electron beam of a cathode ray tube and a fluorescent surface of the cathode ray tube.

FIG. 11 is a diagram showing a misconvergence pattern to be solved by the present invention.

FIG. 12 is a front view showing a state in which a ferrite sheet for convergence correction is attached to a conventional deflection yoke.

FIG. 13 is an explanatory diagram for explaining a state of a screen when a ferrite sheet is pasted on a conventional deflection yoke.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Horizontal deflection coil 2 Vertical deflection coil 3 First coil 4 Second coil 5 Third coil 6 Fourth coil 7 Vertical auxiliary coil 8 Permanent magnet 9,10 Shaft core 11 Shaft core of vertical auxiliary coil 14 Rotating magnet

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H04N 9/28 H01J 29/76

Claims (2)

(57) [Claims] 1. A convergence correction device provided in a deflection yoke having a vertical deflection coil and a pair of horizontal deflection coils, wherein two shafts made of a magnetic material to which a bias magnetic field is applied by a permanent magnet. Core and one shaft center
While winding one coil and the third coil, the other axis
The second coil and the fourth coil are wound around the first coil and the second coil.
Connect the coil to one horizontal deflection coil
And connect the third and fourth coils to the other
Connect the flat deflection coil, positive horizontal deflection current first coil and the magnetic field by the second coil is the bias magnetic field in the same direction next wound on separate axis respectively when flowing,且
One such magnetic field by the third coil and the fourth coil each wound on a separate axis is the bias magnetic field in the opposite direction
When a positive vertical deflection current flows through the vertical deflection coil, the bias magnetic field generated by the vertical deflection current has the same direction as the magnetic field generated by the first coil and the second coil.
A convergence correction device, wherein the convergence correction device and the fourth coil are arranged in a direction opposite to that of the magnetic field. 2. The convergence correction device according to claim 1, wherein the permanent magnet is a cylindrical permanent magnet, and the bias magnetic field by the permanent magnet is made variable by rotating the cylindrical permanent magnet.