JP2900965B2 - 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 self-convergence type deflection yoke mounted on an in-line type color picture tube. It is another object of the present invention to provide a deflection yoke which can easily correct a reverse pattern of a cross miss convergence of a horizontal line without generating a misconvergence of a vertical line.

[0002]

2. Description of the Related Art In an image display apparatus using a three-electron gun in-line type color picture tube, a method for well converging three electron beams emitted from a three-electron gun on a screen surface (on a screen). As one of the methods, there is a method using a deflection yoke of a self-convergence method. The deflection yoke of the self-convergence method
The saddle-type horizontal deflection coil and the saddle-type vertical deflection coil make the horizontal deflection magnetic field a strong pincushion type and the vertical deflection magnetic field a strong barrel type to obtain good convergence.

However, when the vertical deflection angle on the color picture tube is reduced to about 90 °, the above-mentioned magnetic field distribution for obtaining good convergence requires pincushion distortion and barrel distortion in the upper and lower rasters of the screen. Distortion occurs and cannot be put to practical use. Further, when trying to correct the distortion of the upper and lower rasters, the cross-misconvergence shown in FIGS. 4 and 5 occurs, which is not practical. Thus, it has been very difficult to simultaneously satisfy the distortion and convergence of the upper and lower rasters.

Therefore, conventionally, there has been proposed a method of using a saturable reactor or the like in a deflection circuit in order to correct cross-miss convergence and simultaneously satisfy distortion and convergence of upper and lower rasters. However, even if the cross miss convergence is corrected to approximately zero using this method, as shown in FIG.
A so-called cross miss convergence reversal pattern in which a positive cross occurs at the screen intermediate portion b occurs. Therefore, it is not satisfactory as a display device requiring high accuracy.

In a flat face picture tube having a small screen curvature, the above-mentioned inverted pattern is more emphasized, which may cause a problem in general use other than high precision use.

Further, conventionally, in order to correct the reverse pattern of the cross miss convergence, it is necessary to manually add a magnetic piece or the like for each deflection yoke and adjust it for each deflection yoke. It was bad.

From the inversion pattern shown in FIG. 6, the conventional method has a smaller value than the optimum magnetic field distribution (ideal magnetic field distribution that simultaneously satisfies the distortion and convergence of the upper and lower rasters).
It can be seen that the vertical deflection magnetic field deviates in the direction of the pincushion magnetic field at the screen middle part b and in the barrel-type magnetic field direction at the screen peripheral part a.

The inventor of the present invention has disclosed a deflection yoke which can easily correct the reverse pattern of the cross miss convergence, can eliminate the distortion of the upper and lower rasters and can achieve both convergence and improve the convergence quality. Hei 4-341627 (filing date: November 2, 1992
7th). FIG. 7 shows the deflection yoke associated with FIG. 8 of this prior application.

This deflection yoke connects the winding starts S1 and S2 of a pair of saddle type vertical deflection coils L1 and L2 to have the same potential between the winding starts.
The diode D connected in parallel with the opposite polarity between T2
1 and D2 are connected to coils L1 and L2.
2 and in parallel. Then, four-pole frame correction coils L5 and L6 are connected in series to the diode block. The coils L3 and L4 connected in series to the coils L1 and L2 are the same frame correction coils as in the prior art, and generate a pincushion distortion type vertical deflection magnetic field. Note that the frame correction coils L5 and L6 are provided at positions where the frame correction coils L3 and L4 are provided as in the related art (that is, at positions behind the horizontal and vertical deflection coils (from the electron gun)), and A magnetic field similar to that of the correction coils L3 and L4 is formed. The frame correction coils L3 and L4 are first frame correction coils, and the frame correction coils L5 and L6 are second frame correction coils.

The operation of the deflection yoke will be described.
First, in the section from the position where the vertical deflection angle is 0 ° (that is, on the screen x-axis in FIG. 6) until the diodes D1 and D2 are turned on (the section from the screen to the substantially middle portion b), the saddle type vertical deflection coil is used. Start of winding S1, S2 of L1, L2 and tap T
1 and T2 are equal to the current I2 flowing between the winding ends F1 and F2 and the taps T1 and T2 (I1 =
I2). At this time, the coils are adjusted in advance so as to form a magnetic field distribution that optimizes (minimizes) the cross-misconvergence in the substantially middle portion b of the screen.

Next, in a section where the vertical deflection angle further increases and the diodes D1 and D2 are turned on and the vertical deflection angle reaches the peripheral portion a of the screen, an increase in the vertical deflection current I1 between the winding start S and the tap is suppressed. (Since the shunt current I3 flows on the diode block side, that is, on the second frame correction coils L5 and L6), the magnetomotive force in the winding start S and the portion between the taps is also suppressed. Therefore, the magnetic field distribution formed after the diodes D1 and D2 are turned on changes in the direction of the pincushion magnetic field distribution more than the magnetic field distribution formed before the diodes were turned on. Therefore, the magnetic field distribution, which tends to shift in the barrel-shaped magnetic field distribution direction at the peripheral portion a of the screen in the conventional device, can be corrected by the present device, and the occurrence of the inversion pattern can be suppressed.

FIGS. 8A and 8B schematically show the magnetic field distribution before the diode is turned on and after the diode is turned on.
(This figure is a cross-sectional view of a pair of vertical deflection coils L1 and L2). It can also be seen from the figure that the magnetic field distribution that tends to shift in the barrel-shaped magnetic field distribution direction at the periphery of the screen can be corrected by turning on the diode.

The position where the diode is turned on is adjusted within the range of the substantially middle portion b of the screen so that the occurrence of the inversion pattern is minimized.

Here, if the frame correction coils L5 and L6 are formed so that the magnetic field generated from the coils has the same polarity as the vertical deflection magnetic field, after the diodes D1 and D2 are turned on, the deflection yoke is turned off. The center of the vertical deflection magnetic field moves toward the electron gun (since the frame correction coils L5 and L6 are located horizontally (behind the electron gun) with respect to the vertical deflection coils L1 and L2). At this time, the horizontal deflection magnetic field distribution does not change,
Since the vertical deflection magnetic field distribution will move relatively,
The cross miss convergence changes in the forward cross direction.

By the above-described operation, the deflection yoke shown in FIG. 7 has the reverse cross caused by the tendency of the vertical deflection magnetic field to be displaced in the barrel-shaped magnetic field distribution direction at the peripheral portion a of the screen, and the substantially middle portion b of the screen. It is possible to suppress the occurrence of the reversal pattern (see FIG. 6) of the two cross misconvergences of the positive cross, which has occurred because the vertical deflection magnetic field tends to shift in the direction of the pincushion magnetic field distribution.

In the peripheral portion a of the screen, the shunt current I3 flows through the second frame correction coils L5 and L6, and the magnetic field generated from the first frame correction coils L3 and L4 causes the second frame correction coils L5 and L4 to generate a shunt current. The magnetic field generated from L6 is added. Therefore, the misconvergence of the horizontal line of the center beam (G) with respect to the side beams (R and B), which is generated at the peripheral portion a of the screen and cannot be corrected only by the magnetic field generated from the first frame correction coils L3 and L4. The occurrence can be suppressed at the same time (see FIG. 9).

However, in the above-described cross-misconvergence inversion pattern correction method, since the magnetic field of the vertical deflection coil is dynamically changed, when the occurrence of misalignment of the horizontal line is suppressed, the side beam (R and In some cases, the vertical line of B) is shifted and misconvergence as shown in FIG. 10 occurs.

[0018]

The problem to be solved by the present invention is that it is possible to easily correct the reversal pattern of the horizontal cross miss convergence without generating the vertical misconvergence. What is necessary is to take measures to make the deflection yoke capable of achieving both the elimination of the distortion of the raster and the convergence and the remarkable improvement of the convergence quality.

[0019]

Therefore, in order to solve the above-mentioned problems, the present invention provides:

In a self-convergence type deflection yoke comprising at least one pair of saddle type horizontal deflection coils and at least one pair of saddle type vertical deflection coils,

A winding start side of each winding of the at least one pair of saddle type vertical deflection coils is connected to have the same potential, and a tap is provided in the middle of each winding of the at least one pair of saddle type vertical deflection coils. ,

A diode block comprising a plurality of diodes connected in parallel with opposite polarities to each other between the taps, and at least one pair of frame correction coils connected in series with the diode block so as to sandwich the diode block. Connect a series circuit,

A first diode circuit comprising a resistor and a diode connected in series, connected in parallel to the diode block and one of the pair of frame correction coils;

A second diode circuit formed by connecting a resistor and a diode in series is connected in parallel to the diode block and the other of the pair of frame correction coils. To provide a deflection yoke.

[0025]

FIG. 1 shows a main part of an embodiment. In this embodiment, the saddle-type horizontal deflection coil is the same as a conventional general deflection coil, so that illustration and description of the coil are omitted here. The same parts as those in FIG. 7 are denoted by the same reference numerals, and a specific description of the parts will be omitted.

One coil L5 of the second frame correction coil
(Upper coil) and the other coil L6 (lower coil) are connected so as to sandwich a diode block composed of diodes D1 and D2. The series circuit of the coil L5, the diode block, and the coil L6 is connected to the tap T1,
Connect between T2. A first diode circuit formed by connecting a fixed resistor R3 and a diode D3 in series is connected to a coil L
5 and the diode block are connected in parallel. A second diode circuit formed by connecting the fixed resistor R4 and the diode D4 in series is connected in parallel to the coil L6 and the diode block. The polarity of the diode D3 of the first diode circuit is a polarity for flowing the current in the upper deflection current direction, and the polarity of the diode D4 of the second diode circuit is a polarity for the current in the lower deflection current direction.

Next, the operation of correcting vertical line misconvergence according to this embodiment will be described with reference to FIGS. FIG. 2 is a diagram for explaining a magnetic field generated from the second frame correction coils L5 and L6 at the time of upward deflection, and FIG.
FIG. 9 is a diagram for explaining a magnetic field generated from the frame correction coils L5 and L6 of FIG. Thick arrows in FIGS. 2 and 3 indicate the direction of deflection that each beam receives.

When the first and second diode circuits are not connected, the upper coil L of the second frame correction coil
5 and the current flowing through the lower coil L6 are equal, and the magnetic field generated from the second frame correction coil is a pincushion-type correction deflection magnetic field distorted vertically symmetrically (FIG. 2B, FIG. 3 (b)).

When the first and second diode circuits are connected, at the time of upward deflection, the diode D
1 and the diode D3 are turned on, and the current I3 flowing through the circuit on the second frame correction coil side is divided into the current I4 flowing through the upper coil L5 and the current I5 flowing through the first diode circuit. Then, the magnetic field generated from the upper coil L5 of the second frame correction coil is weaker than the magnetic field generated from the lower coil L6, and the pincushion is vertically asymmetric as shown in FIG. In the magnetic field distribution. This magnetic field distribution can be considered based on a combination of the conventional vertically symmetric pincushion-type magnetic field distribution shown in FIG. 2B and the quadrupole magnetic field distribution shown in FIG. 2C. FIG.
In the quadrupole magnetic field distribution shown in (c), the upper coil is shown in FIG.
The lower coil has the same polarity as the lower coil shown in FIG. 2B, and the lower coil has the same polarity as the lower coil shown in FIG. The quadrupole magnetic field distribution is determined by the side beam R
Are magnetic field distributions for deflecting the side beam B in the X-axis negative direction and the side beam B in the X-axis negative direction.

Therefore, the diode D1 and the diode D
When 3 is turned on (when the beam scans the upper peripheral portion of the screen), each beam is deflected as shown in FIG. The direction of deflection of the side beams (R and B) is opposite to the direction of the convergence shift in the peripheral portion of the upper screen shown in FIG. Therefore, in the present embodiment, the vertical line misconvergence in the upper screen peripheral portion can be corrected.

At the time of the lower deflection, similarly to the upper deflection, at the time of deflection of the lower peripheral portion of the screen (diode D2 and diode D2).
4 is on), the magnetic field distribution shown in FIG.
A pincushion-type magnetic field distribution, which is vertically asymmetric and strong on the upper side as shown in FIG. 3A, is generated by combining the quadrupole magnetic field distribution shown in FIG. Side beams (R and B) shown in FIG.
Is the direction opposite to the direction of the convergence shift in the lower peripheral portion of the screen shown in FIG.
Therefore, in the present embodiment, the vertical line misconvergence in the lower peripheral portion of the screen can also be corrected.

The vertical line misconvergence correction amount is determined by the constants of the fixed resistors R3 and R4 of the first and second diode circuits. Therefore, at least one of the fixed resistors R3 and R4 may be a variable resistor so that the upper and lower correction amounts can be adjusted independently.

As a matter of course, in the present embodiment, similarly to the deflection yoke of the earlier application shown in FIG. 7, the reverse pattern of the cross miss convergence can be easily corrected.

Here, when the deflection yoke body generates a large amount of heat (during high-frequency operation) or when the deflection yoke is used in an environment with a high ambient temperature, such as inside a display device,
The DC resistance of the coils L1 and L2 may significantly increase due to heat (in that case, of course, the DC resistance between the winding start and the tap, which are part of the coils L1 and L2, also significantly increases). Therefore, in the above embodiment, the coils L1 and L
The shunt ratio of the parallel circuit composed of the coil-side circuit, which is the portion between the taps T1 and T2 including the winding start S1 and S2, and the diode block-side circuit is set to optimize the convergence due to the influence of heat. May deviate from the set value. (Note that the diode block side circuit includes the diode block (D1, D2), the pair of frame correction coils (L5, L6), the first diode circuit (R3, D3), and the second diode circuit. (This is a circuit composed of (R4, D4).)

Therefore, another embodiment shown in FIG.
Includes, in order to cancel the DC resistance increase due to the temperature rise of the coil side circuit (the portion between the taps including the winding start S1 and S2), a temperature compensating circuit 22 in which the DC resistance is reduced by the temperature rise, in series with the coil side circuit. It is provided. As the temperature compensation circuit 22, a circuit having a DC resistance characteristic in which the resistance is reduced by an amount corresponding to canceling the DC resistance increase of the coil side circuit is used (that is, the coil side circuit and the diode block side circuit of the parallel circuit are used). Which has a DC resistance characteristic that can always keep the shunt ratio constant). The temperature compensation circuit 22 includes, for example, a thermistor M1 having a negative polarity and fixed resistors R22 and R23 as shown in FIG.
The position where the temperature compensation circuit 22 is provided may be any position as long as it is a coil side circuit in the parallel circuit.

In each of the above embodiments, the saddle type vertical deflection coil is shown as a single pair. However, the saddle type vertical deflection coil may have a plurality of pairs. In this case, at least one of the plural pairs is used.
A diode block, a second frame correction coil, and first and second diode circuits may be provided for the pair. Further, the diode block may be a zener diode block including a plurality of zener diodes connected in series with opposite polarities.

[0037]

As described above, the deflection yoke according to the present invention does not cause vertical misconvergence.
The reversal pattern of the horizontal cross miss convergence can be easily corrected, the elimination of raster distortion at the top and bottom of the screen and the convergence can be achieved, and the convergence quality can be greatly improved.

Further, this deflection yoke can easily correct the inversion pattern by adjusting the turn-on position of the diode block, and can adjust the vertical resistance by adjusting the resistance value of the resistors in the first and second diode circuits. The correction amount of the line misconvergence can be easily adjusted. Therefore, the work of manually adding and correcting a magnetic piece or the like for each deflection yoke as in the related art is greatly reduced, and the deflection yoke of the present invention can improve work efficiency and improve productivity. it can.

The deflection yoke provided with the temperature compensating circuit can cancel the DC resistance change in the portion between the taps including the winding start of the vertical deflection coil due to the temperature change, in addition to the above-mentioned effects. , The shunt ratio of the parallel circuit of the portion between the taps including the beginning of winding and the circuit on the diode block side is always kept at an optimum value, and optimum convergence is always obtained even when used in a high temperature state such as at the time of high frequency operation.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment.

FIG. 2 shows a second frame correction coil L5, L6 during upward deflection.
FIG. 4 is a diagram for explaining a magnetic field generated from the data.

FIG. 3 shows the second frame correction coils L5 and L6 at the time of downward deflection.
FIG. 4 is a diagram for explaining a magnetic field generated from the data.

FIG. 4 is a diagram for explaining cross miss convergence;

FIG. 5 is a diagram for explaining cross miss convergence;

FIG. 6 is a diagram for explaining a reverse pattern of cross miss convergence.

FIG. 7 shows a deflection yoke of the earlier application.

FIG. 8 is a diagram showing a magnetic field distribution for correcting an inversion pattern.

FIG. 9 is a diagram for explaining misconvergence of a horizontal line.

FIG. 10 is a diagram for describing vertical line misconvergence.

FIG. 11 is a diagram showing another embodiment.

[Explanation of symbols]

 D1 to D4 Diode L1, L2 Vertical deflection coil L3, L4 First frame correction coil L5, L6 Second frame correction coil R1 to R4 Fixed resistor VR1 Variable resistor T1, T2 Tap S1, S2 Start of winding F1, F2 End of winding 22 Temperature compensation circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H04N 9/28 H01J 29/76

Claims (4)

(57) [Claims] 1. A self-convergence type deflection yoke comprising at least a pair of saddle type horizontal deflection coils and at least a pair of saddle type vertical deflection coils, wherein each winding of the at least one pair of saddle type vertical deflection coils is provided. Are connected at the same potential, and a tap is provided in the middle of each winding of the at least one pair of saddle type vertical deflection coils, and a plurality of diodes connected in parallel with opposite polarities between the taps are provided. And a series circuit of at least a pair of frame correction coils connected in series with the diode block so as to sandwich the diode block, and a resistor and a diode are connected in series. A diode circuit is connected to one of the diode block and the pair of frame correction coils. A second diode circuit, which is connected in parallel to the frame correction coil of the above and is connected in series with a resistor and a diode, is connected to the diode block and the other frame correction coil of the pair of frame correction coils. A deflection yoke connected in parallel to the deflection yoke. 2. A self-convergence type deflection yoke comprising at least one pair of saddle type horizontal deflection coils and at least one pair of saddle type vertical deflection coils, wherein each winding of said at least one pair of saddle type vertical deflection coils is provided. Are connected at the same potential, and taps are provided in the middle of each winding of the at least one pair of saddle type vertical deflection coils, and a plurality of Zeners connected in series with opposite polarities between the taps are provided. A zener diode block composed of a diode is connected to a series circuit of at least a pair of coma correction coils connected in series with the zener diode block so as to sandwich the zener diode block, and a resistor and a diode are connected in series. A first diode circuit comprising: And a second diode circuit comprising a resistor and a diode connected in series to the Zener diode block and the pair of the frame correction coils. A deflection yoke connected in parallel to the other of the frame correction coils. 3. The deflection yoke according to claim 1, wherein a circuit comprising the diode block, the at least one pair of frame correction coils, the first diode circuit, and the second diode circuit is a diode block side circuit, In the parallel circuit of the diode block side circuit and the winding between the taps of the at least one pair of saddle type vertical deflection coils, on the winding side between the taps, a temperature compensation circuit in which the DC resistance decreases due to temperature rise. Provided in series, the temperature compensation circuit cancels an increase in DC resistance due to a temperature rise in a winding portion between the taps in the parallel circuit, and the winding side between the taps and the diode block side of the parallel circuit. A deflection yoke having a DC resistance characteristic for keeping a shunt ratio with a circuit constant. 4. The deflection yoke according to claim 2, wherein a circuit comprising said Zener diode block, said at least one pair of frame correction coils, said first diode circuit, and said second diode circuit is a Zener diode block side circuit. In a parallel circuit of the Zener diode block side circuit and the winding between the taps of the at least one pair of saddle type vertical deflection coils, the temperature at which the DC resistance decreases due to the temperature rise on the winding side between the taps. A compensation circuit is provided in series, the temperature compensation circuit cancels an increase in DC resistance due to a rise in temperature of a winding portion between the taps in the parallel circuit, and the winding side between the taps of the parallel circuit and the The deflection yoyo has a DC resistance characteristic for maintaining a constant current dividing ratio with the Zener diode block side circuit. Click.