JPH06284434A - Deflection yoke - Google Patents

Abstract

PURPOSE:To easily correct an inversion pattern of cross mis-convergence of a lateral line without generating mis-convergence of a longitudinal line especially with respect to the self-convergence system deflection yoke mounted on an in-line color picture tube. CONSTITUTION:A current flowing to an upper side frame correction coil L5 is reduced by 1st diode circuits R3, D3 at the deflection of an upper pattern circumferential part. On the other hand, a current flowing to a lower side frame correction coil L6 is reduced by 2nd diode circuits R4, D4 at the deflection of a lower pattern circumferential part. Thus, production of mis-convergence of a longitudinal line at the correction of inverted pattern of a cross mis- convergence is prevented.

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. Further, it is an object of the present invention to provide a deflection yoke which can easily correct a reversal pattern of horizontal cross misconvergence without causing vertical line misconvergence.

[0002]

2. Description of the Related Art A method for satisfactorily focusing (converging) three electron beams emitted from a three-electron gun on a screen surface (screen) in an image display device using a three-electron gun in-line color picture tube. One of the methods is to use a deflection yoke of a self-convergence type. The self-convergence deflection yoke is
With the saddle type horizontal deflection coil and the saddle type vertical deflection coil, the horizontal deflection magnetic field is made into a strong pincushion type and the vertical deflection magnetic field is made into a strong barrel type to obtain good convergence.

However, when the vertical deflection angle on the color picture tube is not as large as about 90 °, the above-mentioned magnetic field distribution for obtaining good convergence shows pincushion type distortion or barrel type in the upper and lower rasters of the screen. It is distorted and cannot be put to practical use. Further, when trying to correct the distortion of the upper and lower rasters, the cross-miss convergence shown in FIGS. 4 and 5 occurs, which is not practically used in the same manner. Thus, it was very difficult to satisfy the distortion and the convergence of the upper and lower rasters at the same time.

Therefore, conventionally, in order to correct the cross-miss convergence and simultaneously satisfy the distortion and the convergence of the upper and lower rasters, a method using a saturable reactor or the like in the deflection circuit has been considered. However, even if the cross miss convergence is corrected to about zero using this method, as shown in FIG.
A so-called cross-miss convergence reversal pattern, which is a positive cross, occurs in the middle part b of the screen. Therefore, it is not satisfactory for a display device that requires high precision.

Further, in a flat face picture tube having a small curvature of the screen, the inversion pattern is more emphasized, which may cause a problem even in general applications which are not high precision applications.

Further, conventionally, in order to correct the reversal pattern of the cross-miss convergence, it is necessary to manually add a magnetic piece or the like for each deflection yoke and adjust each piece individually, so that the production efficiency is improved. It was bad.

From the reversal pattern of FIG. 6, in the conventional method, as compared with 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 is deviated in the pincushion type magnetic field direction at the screen intermediate portion b and in the barrel type magnetic field direction at the screen peripheral portion a.

Therefore, the inventors of the present invention have proposed a deflection yoke which can easily correct the reverse pattern of the cross-miss convergence and can eliminate the distortion of the raster at the top and bottom of the screen and the convergence, thereby improving the convergence quality. No. 4-341627 (filing date: November 2, 1992)
7th) The deflection yoke associated with FIG. 8 of this earlier application is shown in FIG.

In this deflection yoke, the winding start S1 and S2 of the pair of saddle type vertical deflection coils L1 and L2 are connected to each other so that the winding start has the same potential, and the tap T1 in the middle of the winding is connected.
Diode D connected in parallel with opposite polarities between T2
A diode block consisting of 1 and D2 is connected to coils L1 and L
Connect in parallel with 2. Then, four pole coma 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 coma correction coils similar to the conventional one, and generate a pincushion distortion type vertical deflection magnetic field. The frame correction coils L5 and L6 are provided at the positions where the same frame correction coils L3 and L4 as in the conventional case are provided (that is, behind the horizontal and vertical deflection coils (from the electron gun)). 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 x axis of the screen of FIG. 6) to when the diodes D1 and D2 are turned on (the section up to the substantially middle portion b of the screen), the saddle type vertical deflection coil Each winding start S1 and S2 of L1 and L2 and tap T
The current I1 flowing between 1 and T2 is 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 in which the cross-miss convergence of the approximately middle portion b of the screen is optimal (minimum).

Next, when 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. (Because the shunt current I3 flows to the diode block side, that is, the second coma correction coils L5 and L6 side), the magnetomotive force between 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 is changed in the pincushion type magnetic field distribution direction from the magnetic field distribution formed before the diodes are 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 in this device, and the occurrence of the reversal pattern can be suppressed.

Magnetic field distributions before the diode is turned on and after the diode is turned on are schematically shown in FIGS. 8 (a) and 8 (b).
(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, which tends to shift in the barrel-shaped magnetic field distribution direction at the peripheral portion of the screen, can be corrected by turning on the diode.

The position at which the diode is turned on is adjusted within the range of the substantially middle portion b of the screen so that the generation of the inverted pattern is minimized.

If the coma 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 on. The center of the vertical deflection magnetic field moves to the electron gun side (because the coma correction coils L5 and L6 are located horizontally and behind the vertical deflection coils L1 and L2 (from the electron gun)). At this time, the horizontal deflection magnetic field distribution does not change,
Since the vertical deflection magnetic field distribution will move relatively,
Cross-miss convergence changes in the positive cross direction.

As a result of the above operation, the deflection yoke shown in FIG. 7 has a reverse cross that occurs because the vertical deflection magnetic field tends to shift in the barrel-shaped magnetic field distribution direction at the screen peripheral portion a, and at the screen intermediate portion b. It is possible to suppress the occurrence of the reversal pattern (see FIG. 6) of both cross misconvergence of the positive cross, which is generated because the vertical deflection magnetic field tends to shift in the pincushion type magnetic field distribution direction.

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 coil L5 and L5. The magnetic fields generated from L6 are added. Therefore, the misconvergence of the horizontal line of the center beam (G) with respect to the side beams (R and B), which occurs in the peripheral portion a of the screen, which could not be corrected only by the magnetic field generated from the first coma correction coils L3 and L4. Occurrence can be suppressed at the same time (see FIG. 9).

However, in the above-mentioned cross-misconvergence inversion pattern correction method, since the magnetic field of the vertical deflection coil is dynamically changed, when the occurrence of horizontal line misconvergence is suppressed, the side beam (R and In rare cases, the vertical line in B) was misaligned to cause misconvergence as shown in FIG.

[0018]

SUMMARY OF THE INVENTION The problem to be solved by the present invention is to easily correct the reversal pattern of the horizontal cross misconvergence without causing vertical line misconvergence. What is to be done is to make a deflection yoke that can achieve both raster distortion elimination and convergence and can significantly improve convergence quality.

[0019]

In order to solve the above problems, the present invention provides

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,

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

Between the taps, a diode block composed of a plurality of diodes connected in reverse polarity to each other in parallel, and at least a pair of coma correction coils connected in series with the diode block so as to sandwich the diode block. Connect a series circuit,

A first diode circuit formed by connecting a resistor and a diode in series is connected in parallel to the diode block and one of the pair of frame correcting coils,

A second diode circuit in which a resistor and a diode are connected in series is connected in parallel to the diode block and the other frame correction coil of the pair of frame correction coils. A deflection yoke is provided.

[0025]

EXAMPLE FIG. 1 shows the essential part of one example. In this embodiment, since the saddle type horizontal deflection coil is the same as the conventional one, the coil is not shown and described here. Further, the same parts as those in FIG. 7 are designated by the same reference numerals, and the specific description of those parts will be omitted.

One coil L5 of the second frame correction coil
A diode block composed of the diodes D1 and D2 is connected so as to be sandwiched between the (upper coil) and the other coil L6 (lower coil). Connect the series circuit of the coil L5, the diode block, and the coil L6 to the tap T1,
Connect between T2. The first diode circuit formed by connecting the fixed resistor R3 and the diode D3 in series is connected to the 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 that allows a current in the upper deflection current direction to flow, and the polarity of the diode D4 of the second diode circuit is a polarity that allows a current in the lower deflection current direction to flow.

Next, the vertical line misconvergence correction operation 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 coma correction coils L5, L6 during upward deflection, and FIG. 3 shows a second magnetic field during downward deflection.
It is a figure for demonstrating the magnetic field which generate | occur | produces from top correction coil L5, L6. The thick arrows in FIGS. 2 and 3 indicate the deflection directions received by the respective beams.

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

When the first and second diode circuits are connected, the diode D is provided in the peripheral portion of the upper screen during the upper deflection.
1 and the diode D3 are turned on, the current I3 flowing through the circuit on the side of the second frame correction coil is divided into a current I4 flowing through the upper coil L5 and a current I5 flowing through the first diode circuit. The magnetic field generated from the upper coil L5 of the second top correction coil is weaker than the magnetic field generated from the lower coil L6, and is vertically asymmetrical as shown in FIG. Because it has a magnetic field distribution. This magnetic field distribution is considered to be a combination of the conventional vertically symmetrical pincushion type magnetic field distribution shown in FIG. 2B and the quadrupole magnetic field distribution shown in FIG. 2C. Figure 2
In the quadrupole magnetic field distribution shown in (c), the upper coil is shown in FIG.
2B shows the magnetic field distribution generated from the one having the opposite polarity to the upper coil and the lower coil having the same polarity as the lower coil shown in FIG. And this quadrupole magnetic field distribution is
Is a magnetic field distribution that deflects B in the X-axis positive direction and B of the side beam in the X-axis negative direction.

Therefore, the diode D1 and the diode D
When 3 is on (when the beam is scanning the peripheral portion of the upper 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 deviation of the convergence in the peripheral portion of the upper screen shown in FIG. Therefore, the present embodiment can correct vertical line misconvergence in the peripheral portion of the upper screen.

Similarly to the case of the upper deflection, the case of the lower deflection of the peripheral portion of the screen (the diode D2 and the diode D) is also performed.
4 is on), the magnetic field distribution shown in FIG.
A pincushion type magnetic field distribution as shown in FIG. 3 (a) that is asymmetric in the vertical direction and strong in the upper side is generated by combining the quadrupole magnetic field distribution shown in FIG. Side beams (R and B) shown in FIG. 3 (a)
The direction of the deflection is in the direction opposite to the direction of the convergence deviation in the lower screen peripheral portion shown in FIG.
Therefore, the present embodiment can correct the vertical line misconvergence in the peripheral portion of the lower screen.

The amount of vertical line misconvergence correction 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 correction amounts of the upper side and the lower side can be adjusted independently.

Of course, this embodiment can easily correct the reversal pattern of the cross-miss convergence like the deflection yoke of the previous application shown in FIG.

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 where the ambient temperature is high such as inside the display device,
The DC resistance of the coils L1 and L2 may be significantly increased by heat (in that case, naturally, the DC resistance between the winding start and the tap, which is a part of the coils L1 and L2, is also significantly increased). Therefore, in the above embodiment, the coils L1, L
The shunt ratio of the parallel circuit including the coil side circuit, which is the portion between the taps T1 and T2 including the winding start S1 and S2 of the second winding, and the diode block side circuit is set so that the convergence is optimized due to the influence of heat. May deviate from the specified value. (Note that the diode block side circuit means the diode block (D1, D2), the pair of frame correction coils (L5, L6), the first diode circuit (R3, D3), and the second diode circuit. (A circuit consisting of R4 and D4)

Therefore, another embodiment shown in FIG.
In order to cancel the increase in DC resistance due to temperature rise of the coil side circuit (portion between taps including winding start S1 and S2), a temperature compensating circuit 22 whose DC resistance decreases due to temperature rise is connected in series with the coil side circuit. It is provided. As the temperature compensation circuit 22, one having a DC resistance characteristic in which the resistance is reduced by an amount corresponding to canceling out the increase in the DC resistance of the coil side circuit (that is, the coil side circuit and the diode block side circuit of the parallel circuit is used). The one that has the direct current resistance characteristic that can always maintain a constant diversion ratio). The temperature compensation circuit 22 is composed of a thermistor M1 having a negative polarity and fixed resistors R22 and R23 as shown in FIG.
The temperature compensation circuit 22 may be provided at 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 one pair, but it may be provided with a plurality of pairs. In this case, at least one of the plurality of pairs is used.
The diode block, the second frame correction coil, and the first and second diode circuits may be provided in pairs. 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 can prevent vertical line misconvergence from occurring.
It is possible to easily correct the reversal pattern of the cross-mis-convergence of the horizontal line, and it is possible to achieve both the distortion elimination of the rasters at the top and bottom of the screen and the convergence, and to significantly improve the convergence quality.

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

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

[Brief description of drawings]

FIG. 1 is a diagram showing an example.

FIG. 2 shows second frame correction coils L5 and L6 during upward deflection.
It is a figure for explaining the magnetic field generated from.

FIG. 3 shows second frame correction coils L5 and L6 during downward deflection.
It is a figure for explaining the magnetic field generated from.

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 the deflection yoke of the previous 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 horizontal lines.

FIG. 10 is a diagram for explaining misconvergence of vertical lines.

FIG. 11 is a diagram showing another embodiment.

[Explanation of symbols]

 D1 to D4 Diodes L1 and L2 Vertical deflection coils L3 and L4 First frame correction coil L5 and L6 Second frame correction coil R1 to R4 Fixed resistance VR1 Variable resistance T1 and T2 Taps S1 and S2 Winding start F1 and F2 Winding end 22 Temperature compensation circuit

Claims (4)

[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. Of the at least one pair of saddle-type vertical deflection coils, and a plurality of diodes connected in parallel to each other in opposite polarities. A series circuit of a diode block consisting of and a at least pair of coma 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 provided in 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 No. 1 and has a resistor and a diode connected in series, in the diode block and the other frame correction coil of the pair of frame correction coils. A deflection yoke characterized by being connected in parallel with each other. 2. A self-convergence 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 of the at least one pair of saddle type vertical deflection coils is wound. 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 Zeners connected in series with opposite polarities are provided between the taps. Connect a series circuit of a Zener diode block consisting of a diode and 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 connect a resistor and a diode in series. The first diode circuit is A second diode circuit connected in parallel to one of the pair of coma-correcting coils and connected in series with a resistor and a diode. A deflection yoke connected in parallel to the other frame correction coil of the frame correction coils. 3. The deflection yoke according to claim 1, wherein the diode block, the at least one pair of frame correction coils, the first diode circuit, and the second diode circuit are diode block side circuits. 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, a temperature compensating circuit whose DC resistance decreases due to temperature rise is provided on the winding side between the taps. Provided in series, the temperature compensation circuit cancels an increase in DC resistance due to a temperature rise of a winding portion between the taps in the parallel circuit, and a winding side between the taps of the parallel circuit and a diode block side. A deflection yoke having a DC resistance characteristic for keeping a diversion ratio with a circuit constant. 4. The deflection yoke according to claim 2, wherein the Zener diode block, the at least one pair of coma correction coils, the first diode circuit, and the second diode circuit are provided in a Zener diode block side circuit. In the 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, on the winding side between the taps, the temperature at which the DC resistance decreases due to the temperature rise A compensation circuit is provided in series, and the temperature compensation circuit cancels an increase in DC resistance due to a temperature rise 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 yaw is characterized by having a DC resistance characteristic that maintains a constant diversion ratio with the Zener diode block side circuit. Click.