JPH10108036A - Horizontal s-shape correction circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continuously change and adjust a correction amount with simple constitution and to also appropriately perform M-shape distortion correction simultaneously by on/off controlling a part of a capacitor group corresponding to control signals adjusted, corresponding to the waveform of a vertical deflection cycle. SOLUTION: An S-shape correction capacitor group connected to the other end of a horizontal deflection coil 1 is constituted of a directly grounded main capacitor 7 and an auxiliary capacitor 10 turned on/off with the ground by an electronic switch element 11. An electronic switch circuit is constituted of an FET 11 which is the electronic switch element and a diode 12 connected in parallel between the drain and the source. The output rectangular waves Vg of a monostable multivibrator 13 triggered by the pulses Vh of a horizontal deflection cycle are added to the gate of the FET 11. The output rectangular waves Vg are external control signals for controlling the on/off of the FET 11, and the electronic switch element 11 repeats the on/off within a single horizontal deflection cycle period.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device using a picture tube, which reduces the so-called M-shaped distortion in which the horizontal linearity of the central portion of an image is reduced at the time of wide-angle deflection. In this case, the invention relates to a technique for eliminating image distortion, such as achieving optimal S-shaped distortion correction of horizontal linearity for each horizontal deflection cycle and also correcting inner pincushion distortion. is there.

[0002]

2. Description of the Related Art When a picture tube having a relatively flat image receiving surface and a wide-angle deflection has been used, the tendency of the horizontal linearity distortion is shown by a solid line in FIG. Tended to have. This is particularly remarkable in a wide picture tube having an aspect ratio of 9:16, and some countermeasures have been required.

FIG. 9 shows an example of the countermeasure. Where 1
Is a horizontal deflection coil, 2 is an S-shaped correction capacitor, and 3 is a secondary resonance circuit for M-shaped distortion correction. Usually, the secondary resonance circuit 3 is not often added, and a sawtooth-shaped horizontal deflection current flows through a series circuit of the horizontal deflection coil 1 and the S-shaped correction capacitor 2 to deflect the electron beam of the picture tube left and right. In FIG. 9, if the capacitance value of the S-shaped correction capacitor 2 is adjusted, the linearity can be corrected by adjusting the extension of the left and right ends with respect to the center. However, as shown by the broken line and the one-dot broken line in FIG. 8, the adjustment of the capacitance value alone cannot remove the contracted portion at the center. This is because the function of the S-shaped correction capacitor 2 alone has an excessively large waveform difference from the current actually required for correction. Therefore, a secondary resonance circuit 3 shown in FIG. 9 is added. Where 4 is a coupling capacitor,
Reference numeral 5 denotes a resonance capacitor, and reference numeral 6 denotes a resonance coil, which forms a secondary resonance circuit that resonates at a frequency twice the horizontal deflection period as a whole. Then, the voltage at both ends of the S-shaped correction capacitor 2 becomes a form in which the secondary resonance waveform is superimposed as shown by the broken line in FIG. 10 from the parabolic wave without the M-shaped correction circuit as shown by the solid line in FIG. The M-shaped distortion shown by the solid line in FIG. 8 is corrected.

When this display device is used as a display terminal of a computer, it is required that the display device be compatible with various horizontal deflection frequencies according to the resolution setting of the signal. FIG. 11 shows an example of the conventional S-character correction in that case. Here, in addition to the S-shaped correction capacitor 7, 7-1, 7-2, 7-3 and auxiliary capacitor groups are added. One end of each of these auxiliary capacitor groups is grounded through electronic switches 8-1, 8-2, 8-3, respectively. The on / off of these electronic switches is controlled by an external control signal. In FIG. 11, when the horizontal deflection frequency is the highest in the range of use, all the electronic switches 8-1 to 8-3 are turned off, and proper correction can be obtained only by the main S-correction capacitor 7. The capacitance value is determined as described above. Then, as the horizontal deflection frequency decreases, the electronic switches 8-1, 8-
2 and 8-3 are switched from off to on so that the auxiliary capacitors 7-1, 7-2, 7-3, etc. are connected in parallel to the main S-shaped correction capacitor 7 so that the overall S-shaped correction capacitor What is necessary is just to set the capacitance value so as to match the horizontal frequency at that time.

[0005] In this case, however, the frequency that is just adapted is limited by the number of electronic switches, and the frequency between them can be corrected only by approximation, so that the quality of the correction is inevitably deteriorated slightly. It is only necessary to increase the number of combinations of the switches and the auxiliary S-shaped correction capacitors, but the circuit scale naturally increases. Also, in FIG. 11, it is possible to perform the M-shaped correction by adding the secondary resonance circuit 3 described above. However, also in this case, if the horizontal frequency changes, the values of the coil and the capacitor in the secondary resonance circuit 3 must be switched, and the circuit becomes enormous.

On the other hand, in addition to the above-mentioned horizontal linearity distortion, another problem associated with a wide-angle deflection picture tube having a flat image receiving surface is an inner pincushion distortion shown in FIG. This is a phenomenon in which pincushion distortion remains in the middle even if side pincushion correction is applied so that the vertical line at the left and right ends becomes a vertical line, and the vertical line that should be vertical curves inward. . This indicates that the horizontal linear extension in the left and right directions is greater in the scanning line near the center than in the upper and lower parts of the image. Therefore, it is necessary to apply a stronger S-shaped correction in this part than in the upper and lower ends. However, it has been difficult until now to change the amount of horizontal S-shaped correction according to the vertical position.

In the past, when a large change in horizontal amplitude such as underscan or overscan of an image was performed, the optimum S-shape correction was performed at a normal horizontal amplitude. Overcorrection,
In the case of overscan, the S-curve correction becomes insufficient, which is a problem. Of course, it is conceivable to switch the value of the S-shaped correction capacitor according to the respective scan amounts by using a switch group as shown in FIG. 11, but the circuit becomes more complicated accordingly.

[0008]

As described above, in the prior art, when a more accurate correction is to be performed or when a variety of horizontal deflection frequencies are to be corrected, the horizontal S including the M-shaped correction is required. The circuit scale for character correction becomes enormous, and optimal compensation is not always performed over the entire corresponding frequency range. In order to solve this problem, it is necessary to develop an S-shaped correction unit in which the correction amount changes continuously, instead of using a conventional switch. Also, regarding the correction of the inner pincushion distortion, an S-shaped correction unit is required in which the correction amount changes continuously according to the vertical position. Therefore,
With respect to this type of continuously variable S-shaped correction, it has been an issue to realize a simple and low-loss circuit.

[0009]

In order to solve the above-mentioned problems, the present invention provides (1) a group of S-shaped correction capacitors connected in series with a horizontal deflection coil and a horizontal scanning period according to an external control signal. Is turned off in the first half of the period and turned on in the horizontal retrace period, and a part of the S-shaped correction capacitor group is turned on.
An electronic switch element for performing off control, wherein a control signal for adjusting a timing at which the electronic switch element is turned off in the first half of the horizontal scanning period according to a waveform of a vertical deflection cycle is used as the external control signal. Horizontal S
(2) a group of S-shaped correction capacitors connected in series with the horizontal deflection coil, and turned on in the first half of the horizontal scanning period and on in the horizontal retrace period in accordance with an external control signal; Turn on a part of the S-shaped correction capacitor group
An electronic switch element for performing off control, wherein a control signal for adjusting a timing at which the electronic switch element is turned off in the first half of the horizontal scanning period according to a horizontal deflection amplitude is used as the external control signal. A horizontal S-shaped correction circuit is provided. (3) As the external control signal, the timing at which the electronic switch element is turned off in the first half of the horizontal scanning period is set closer to the center of the horizontal scanning period as the horizontal deflection period becomes longer. 2 is a horizontal S-shaped correction circuit characterized by adding a second control signal.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A horizontal S-shaped correction circuit according to the present invention will be described below with reference to FIG.
Here, 1 is a horizontal deflection coil as in FIG. A horizontal output pulse Vp is applied to one end of the horizontal deflection coil 1 by the horizontal deflection output circuit 9, and as a result, a sawtooth current Iy flows through the deflection coil 1. The horizontal deflection output circuit 9 is supplied with an excitation pulse Vd from a preceding stage (not shown), and performs a well-known horizontal deflection output operation accordingly.

S connected to the other end of the horizontal deflection coil 1
The character correction capacitor group is turned on / off by an electronic switch element 11 between the main capacitor 7 directly grounded and the ground.
The auxiliary capacitor 10 is turned off. However, unlike the conventional FIG. 11, if the handling frequency is determined, the electronic switch element 11 is not fixed to be turned on or off according to the determined frequency, and is repeatedly turned on and off within one horizontal deflection cycle period. .

An FET 11 serving as an electronic switch element and a diode 1 connected in parallel between its drain and source
2 constitutes an electronic switch circuit. Of course, a switch element such as a bipolar transistor or an IGBT can be used as the electronic switch element in addition to the FET. Note that the diode 12 is connected to flow a current in the reverse direction to the FET 11, but the diode 12 is omitted if the FET 11 can sufficiently flow the reverse current between the drain and the source without any problem. Things are also possible.

The FET 11 has a pulse V having a horizontal deflection cycle.
The output square wave Vg of the monostable multivibrator (hereinafter abbreviated as MM) 13 triggered by h is applied to its gate. This output square wave Vg is an external control signal for controlling ON / OFF of the FET 11. The horizontal deflection period pulse Vh is a horizontal output pulse (horizontal retrace pulse).
It is only necessary to maintain a constant phase relationship with Vp, and it can be formed by shaping the excitation waveform Vd or the horizontal output pulse Vp.

FIG. 2 is a waveform diagram for explaining the state of the operation of FIG. First, FIG. 2A shows the horizontal output pulse Vp. This pulse portion corresponds to a horizontal blanking period tr, and a flat portion corresponds to a horizontal scanning period ts. (The horizontal blanking period tr + the horizontal scanning period ts = horizontal deflection period.)

Next, the trigger pulse Vh of the MM 13 shown in FIG. 2B needs to keep the phase relationship with the horizontal output pulse Vp constant as described above. Is a square-wave pulse that lasts only for a period exceeding. Although a circuit for producing the pulse Vh is not particularly shown, it can be easily obtained by comparing the pulse Vp (or a pulse obtained by transforming the pulse Vp to an appropriate magnitude) with the DC voltage E using a comparator.

The rising point of the square wave pulse Vh is defined as T1. At this time T1, the MM 13 is triggered,
The output is a square wave Vg shown in FIG. The pulse period tmm of the square wave Vg output from the MM 13 is MM
13 can be moved by changing the operating conditions, and the falling time T2 can be freely adjusted.

During a period tmm when the pulse Vg is at a high level, the drain and source of the FET 11 are in a conductive state. Therefore, as shown in FIG. 2D, the drain voltage Vdr of the FET 11 is substantially zero during this period.

At time T2, when the FET 11 changes from on to off, a half sine wave pulse appears at the drain due to the resonance action of the horizontal deflection coil 1 and the S-shaped correction capacitor 7. And this sine wave is a half cycle,
After the time tdr has elapsed, at the time T3 when the zero level is to be interrupted again, the diode 12 is automatically turned on. Therefore, the voltage Vdr at the cathode of the diode 12, that is, the drain point of the FET 11, becomes zero level again from this point.

At this time, the current Idr flowing through the FET 11 and the current Id flowing through the diode 12 are as shown in FIG. If the FET 11 is always on, the current Idr has a saw-tooth waveform like the horizontal deflection coil current Iy as shown by the broken line in the figure. However, in this case, the FET 11 is also connected to the diode 12 only during the time tdr.
Also turns off, the actual current waveform is as shown by the solid line in the figure. The positive portion of the current waveform is the drain current Idr of the FET 11, and the negative portion is the current Id of the diode 12.

As described above, when the FET 11 and the diode 12 are turned off only during the time tdr, the voltage Vcs appearing in the main S-shaped correction capacitor 7 is as shown in FIG. That is, while the FET 11 or the diode 12 is conducting, the total capacitance of the S-shaped correction capacitor is large, and the waveform is a parabolic wave having a small amplitude as shown by I and III in FIG. However, during the period of tdr when both are off, only the capacitor 7 operates as the S-shaped correction capacitor, so that the resonance frequency increases, and the waveform during this period has a large amplitude like II.

The voltage V across the horizontal deflection coil 1 is
l represents a differential value of the current Iy flowing here, that is, its gradient. On the other hand, since the output pulse Vp is zero at least in the horizontal scanning period ts, Vl = -Vcs during this period. Therefore, the value of Vcs in FIG. 2 (F) represents the reverse gradient of the horizontal deflection coil current Iy, and the greater the value, the steeper the gradient.

From this, the fact that the value of Vcs becomes larger near the center of the scanning period as shown in FIG. 2 (F) means that the slope of the current Iy is steep near this, in other words, the scanning speed becomes faster. Thus, the M-shaped distortion in which the central portion is blocked as shown in FIG. 8 can be effectively eliminated. In this case, unlike the method of adding the secondary resonance circuit of FIG. 9, the effect of the correction is only the scanning of the central portion of the screen, and the scanning of the left and right peripheral portions is not affected by the correction. Correction can be performed.

Note that the voltage Vcs shown in FIG.
There is an inflection point at 2 and T3. However, as described above, since this is a value indicating the slope of the current Iy, T2, T3
Before and after, unless the value of the voltage Vcs jumps, I
The shape of y is smoothly connected with the same gradient. Therefore, even if the image of the horizontal scroll passes through this point, there is no inconvenience that the shape of the image suddenly changes discontinuously.

Next, consider the case where the width of the square wave pulse Vg is widened as shown by the broken line in FIG. 2C, and the point at which the level changes from the high level to the low level is closer to the scanning center as in T21. Try. In this case, the period tdr during which both the FET 11 and the diode 12 are off becomes short as tdr1, and the peak value of the pulse Vdr also becomes small.

As described above, moving the time T2 determined by the output pulse width tmm of the MM 13 (that is, the FET 11
(By moving the timing at which the is turned off) means that the magnitude of the pulse Vdr can be moved means that the amount of the M-shaped distortion correction in FIG. Becomes possible.

As described above, in the present embodiment, by adjusting the output pulse width tmm of the MM 13, the M-shaped distortion correction can be performed more finely and more accurately than in the conventional example while having a simpler circuit configuration than in the conventional example. Can be.

Next, as another important application of the present invention, there is an S-shaped correction corresponding to various horizontal deflection frequencies. That is, instead of using a large number of electronic switches to switch the S-shaped correction stepwise as shown in FIG.
The state of the S-curve correction is continuously changed by one electronic switch. In this case, as the external control signal, a control signal for turning off the electronic switch element in the first half of the horizontal scanning period closer to the center of the horizontal scanning period as the horizontal deflection cycle becomes longer is used.
(For example, a control signal for continuously varying the width of the square wave pulse Vg in the embodiment of FIG. 1 is used.)

FIG. 3 shows how the S-shaped correction is continuously performed in response to the change in the horizontal deflection frequency. First, when the horizontal deflection period is as long as th1 as shown in FIG.
The point in time T2 at which T switches from on to off is set near the center of the horizontal scanning period (the ratio of time when the FET 11 is off is shortened). Then, the capacitance of the S-shaped capacitor becomes a parallel value of 7 and 10 in most of the scanning period, and the resonance period with the horizontal deflection coil becomes longer, so that it is possible to cope with a lower horizontal deflection frequency.

Next, as shown in FIG. 3B, the horizontal deflection period is t.
When it becomes shorter than h2, the time T2 at which the FET switches from on to off is set closer to the start side of the horizontal scanning period than in the case of FIG. More, the resonance period of the S-shaped correction is shortened as a whole. When the horizontal deflection cycle th3 becomes the shortest as shown in FIG. 3C, the time T2 at which the FET switches from on to off is set closer to the start side of the horizontal scanning period, and the horizontal scanning period is set. FET11 for most of the period
Is turned off, and the resonance cycle for S-character correction is determined almost entirely by the capacitor 7.

In FIG. 3, (A), (B),
The case of optimally corresponding to the three-point horizontal deflection period shown in (C) has been described. However, as long as the time position of T2 is changed,
Of course, it is possible to optimally correspond to all the horizontal deflection periods during that period.

In the case of FIG. 3, in the case of the longest deflection cycle (A), the M-shaped distortion can be effectively corrected by setting the period in which the FET 11 is turned off only near the center. However, in the case of (C) having a long deflection cycle, the S-shape correction is determined by a single resonance cycle over most of the scanning cycle, so that the M-shape distortion correction effect cannot be obtained as much as (A). If this point is to be further improved, the S-shaped correction control of the present invention may be performed twice as shown in FIG.

That is, in FIG. 4, in addition to FIG. 1, an M-shaped distortion correction circuit 14 for performing another S-character correction switching is added. This M-shaped distortion correction circuit 14 is provided with a second auxiliary S
It comprises a character correction capacitor 15, a second FET 16, a diode 17 associated therewith, and a second MM 18. Here, the on / off operation of the FET 11 is the same as that in FIGS. Newly added FET16
Is turned on over the entire scanning period when the horizontal deflection period is long like th1, and is just suitable with the parallel value of the capacitor 15 and the main S-shaped capacitor 19 which is always fixed and connected to ground. The resonance frequency is set so as to be adjusted.

On the other hand, when the horizontal deflection cycle is short and becomes th3, as shown in FIG. 5, the output time width of the MM 18 is set so that the FET 16 is turned off at time T4 near the scanning center. Then, with the same principle as described above, the auxiliary S
Since the capacitor 15 is cut off, a small half-sine cycle pulse is accumulated from the time T4, so that the M-shaped distortion can be more accurately corrected even if the horizontal deflection period is shorter.

Further, according to the present invention, the problem of inner pinion distortion shown in FIG. 12 can be easily solved. For example, in FIG. 1 according to the present invention, the fact that the degree of S-curve correction can be changed by changing the output pulse width tmm of the MM 13 is utilized, and this may be modulated by a parabolic wave having a vertical period.

FIG. 6 shows the state of the voltage Vcs for the S-shaped correction. That is, MM at the top and bottom of the screen
13, the value of the output pulse width tmm is increased, and the S-shaped correction amount of the horizontal deflection is reduced. On the other hand, in the line at the center in the vertical direction of the screen, the value of tmm is reduced to widen the portion where the resonance capacitance of the S-shaped correction in the central portion in the horizontal direction is reduced. Then, the horizontal linearity of the image is corrected so as to extend at the center, and the distortion in FIG. 12 is eliminated.

FIG. 7 shows an example of a circuit for changing the output pulse width tmm of the MM 13 by electrical control. Here, 19 is an IC element of the MM 13, 20 is a time constant capacitor for determining a pulse width, and 21 is a pnp for constant current.
A transistor, 22 is an emitter resistor, and 23 is a coupling capacitor for applying a vertical parabolic wave.

In this circuit, the time constant capacitor 2
The width tmm of the output pulse is determined by the magnitude of the emitter-collector current Ich of the transistor 21 which charges to 0. That is, when the value of the current Ich is increased,
And the output pulse width tmm is shortened.

The value obtained by adding the base-emitter voltage Vbe of the transistor 21 to the voltage R.Ich across the resistor 22 is the potential difference between the operating power supply voltage Ecc of the circuit and the base voltage Eb. Therefore, if the voltage Eb is moved by external control, the value of the current Ich changes accordingly, and the pulse width tmm of the output changes accordingly.

Further, a parabolic wave V having a vertical period is connected to a base terminal of the transistor 21 via a coupling capacitor 22.
With the addition of pb, the trailing edge of the output square wave undergoes phase modulation with this parabolic wave. As a result, as shown in FIG. 6, the S-shaped correction amount in the central portion is increased with respect to the upper and lower portions of the screen,
The inner pincushion distortion of FIG. 12 can be corrected.

Here, as described above, if the DC value of the base voltage Eb is changed in FIG. 7, the S-shaped correction amount changes. Therefore, if this voltage Eb is obtained from a horizontal deflection amplitude control circuit in the preceding stage (not shown), it is possible to obtain an optimum S-shaped correction amount according to a change in horizontal amplitude. That is, when the horizontal amplitude is large, the value of the voltage Eb is reduced and the value of the charging current Ich is increased. Then, the output pulse width tmm
Becomes shorter, the period tdr becomes longer, and the S-curve correction amount increases. Conversely, when the horizontal amplitude is reduced, the S-shaped correction amount is reduced by increasing the value of the voltage Eb. Therefore, according to the above, the optimum S is always adjusted to the magnitude of the horizontal amplitude.
Character correction can be performed.

Note that the M-time distortion correction adjustment (referred to as (a) adjustment) described with reference to FIG. 2, the adjustment according to the horizontal deflection cycle described as FIG. 3 (referred to as (b) adjustment), and FIG. Adjustment (referred to as (c) adjustment) according to the waveform of the vertical deflection cycle thus performed, and further adjustment (referred to as (d) adjustment) according to the horizontal deflection amplitude.
May be performed in combination as appropriate. As a specific combination, (a) adjustment + (b) adjustment, (a) adjustment +
(C) adjustment, (a) adjustment + (d) adjustment, (b) adjustment +
(C) adjustment, (b) adjustment + (d) adjustment, (c) adjustment +
(D) adjustment, (a) adjustment + (b) adjustment + (c) adjustment,
(A) adjustment + (b) adjustment + (d) adjustment, (a) adjustment +
(C) adjustment + (d) adjustment, (b) adjustment + (c) adjustment +
(D) adjustment, (a) adjustment + (b) adjustment + (c) adjustment +
(D) Adjustment is possible.

[0042]

As described above in detail, according to the horizontal S-shaped correction circuit of the present invention, the horizontal S-shaped correction amount can be continuously changed and adjusted while adopting a simpler structure than the conventional one.
At the same time, the M-shaped distortion can be accurately corrected. Further, the correction of the inner pincushion distortion of the image can be easily achieved, and the optimum S-shaped correction can be performed according to the magnitude of the horizontal amplitude. Therefore, more accurate image distortion correction can be achieved than before, and this greatly contributes to performance improvement. Also, when applied to display devices that support various horizontal deflection frequencies,
It has a simpler circuit configuration than the conventional one, and can perform near-ideal image distortion correction over the entire frequency variable range, which also contributes to improved performance, downsizing of equipment, and cost reduction.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of a horizontal S-shaped correction circuit of the present invention.

FIG. 2 is a waveform chart for explaining the operation of the circuit of FIG. 1;

FIG. 3 is a waveform chart for explaining the operation of the circuit of FIG. 1;

FIG. 4 is a circuit diagram showing another embodiment of the horizontal S-shaped correction circuit of the present invention.

FIG. 5 is a waveform chart for explaining the operation of the circuit of FIG. 4;

FIG. 6 is a waveform chart for explaining the operation of the circuit of FIG. 1;

FIG. 7 is a circuit diagram showing a part of the circuits of FIGS. 1 and 4 in further detail.

FIG. 8 is a characteristic diagram showing an example of a conventional S-shaped correction.

FIG. 9 is a circuit diagram illustrating an example of a conventional S-shaped correction circuit.

FIG. 10 is a waveform chart showing the operation of the circuit of FIG.

FIG. 11 is a circuit diagram showing another example of the conventional S-shaped correction circuit.

FIG. 12 is a diagram for explaining M-shaped distortion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Horizontal deflection coil 2 S-shaped correction capacitor 3 Secondary resonance circuit 5 Secondary resonance capacitor 6 Secondary resonance coil 7 S-shaped correction capacitor 7-1, 7-2, 7-3 ... Auxiliary S-shaped correction capacitor 8-1 , 8-2, 8-3 ... electronic switch 9 horizontal deflection output circuit 10 auxiliary S-shaped correction capacitor 11 FET 12 diode 13 monostable multivibrator (MM) 14 M-shaped distortion correction circuit 19 monostable multivibrator IC 20 time constant Capacitor 21 pnp transistor 22 Emitter resistor 23 Coupling capacitor Iy Horizontal deflection current Vp Horizontal output pulse Vh Horizontal trigger pulse Vg MM output pulse Vdr Drain voltage Vcs S-correction capacitor voltage Vpb Vertical parabolic wave th Horizontal deflection period ts Horizontal scanning period tr Horizontal retrace period tmm MM output pulse width tdr FET output pulse Width, operating power supply voltage Eb base voltage Ich time constant capacitor charging current of the pulse width Ecc circuit of the drain voltage

[Procedure amendment]

[Submission date] July 31, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0031

[Correction method] Change

[Correction contents]

In the case of FIG. 3, in the case of the longest deflection cycle (A), the M-shaped distortion can be effectively corrected by setting the period in which the FET 11 is turned off only near the center. However, in the case of (C) having a short deflection cycle, the S-shape correction is determined by a single resonance cycle over most of the scanning cycle, so that the M-shape distortion correction effect cannot be obtained as much as (A). If this point is to be further improved, the S-shaped correction control of the present invention may be performed twice as shown in FIG.

Claims (3)

[Claims] An S-shaped correction capacitor group connected in series with a horizontal deflection coil, the S-shaped correction capacitor being turned on in a first half of a horizontal scanning period and on in a horizontal retrace period in response to an external control signal; An electronic switch element that controls on / off of a part of the group, wherein, as the external control signal, a timing at which the electronic switch element is turned off in the first half of the horizontal scanning period is adjusted according to a waveform of a vertical deflection cycle. A horizontal S-shaped correction circuit characterized by using a control signal. 2. An S-shaped correction capacitor group connected in series with a horizontal deflection coil, wherein said S-shaped correction capacitor is turned on in the first half of a horizontal scanning period and on in a horizontal retrace period in response to an external control signal. An electronic switch element for controlling on / off of a part of the group; a control signal for adjusting a timing at which the electronic switch element is turned off in the first half of the horizontal scanning period according to a horizontal deflection amplitude as the external control signal. A horizontal S-shaped correction circuit characterized by using. 3. The external control signal further includes a second control signal that sets the timing at which the electronic switch element is turned off in the first half of the horizontal scanning period closer to the center of the horizontal scanning period as the horizontal deflection period becomes longer. 3. The horizontal S-shaped correction circuit according to claim 1, wherein: