JP2000184226A - Distortion correction device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct distortion with a small circuit scale and high precision even at an optional input frequency even when a horizontal size is changed. SOLUTION: The distortion correction device is provided with a horizontal output circuit 101 that generates a deflection current to deflect horizontally an electron beam, a horizontal deflection coil 102 that receives the deflection current, an S-shaped correction capacitor 103 that corrects distortion in the horizontal direction, a frequency discrimination circuit 107 that discriminates an input frequency on the basis of a horizontal synchronizing signal to output polarity and amplitude level information of a corrected waveform, a parabolic waveform generating circuit 106 that generates a correction waveform correcting optimally distortion in the horizontal direction by an output of the frequency discrimination circuit 107, and a corrected waveform superimposing transformer 104 that superimposes an output of the parabolic waveform generating circuit 106.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a distortion correction device for correcting distortion when a display compatible with multi-scanning is performed on a personal computer monitor or the like.

[0002]

2. Description of the Related Art As a conventional horizontal deflection device, there is one disclosed in, for example, JP-A-5-284377.

FIG. 15 is a block diagram of this conventional distortion correction apparatus. Reference numeral 1501 denotes a horizontal output circuit, which includes a horizontal output transistor 1502, a damper diode 1503, a resonance capacitor 1504, a horizontal deflection coil 1505, and a linearity coil 1506. It consists of. Reference numeral 1507 denotes an S-shaped correction capacitor switching circuit. The S-shaped correction capacitor 1508, the S-shaped correction additional capacitor 1509, the FET 1510, and the FE
The control device 1511 turns on and off the T1510.

In the conventional deflecting device configured as described above, when the horizontal synchronization frequency is low, the control device 1511
Detects this and outputs a High signal. Therefore, F
ET1510 conducts and S-shape correction additional capacitor 1
509 is connected in parallel with the S-shaped correction capacitor 1508 to increase the capacitance.

When the horizontal synchronization frequency is high, the control device 1511 detects this and outputs a low signal. Therefore, the FET 1510 becomes non-conductive, and the S-shaped correction capacitor is only the S-shaped correction capacitor 1508. As described above, the S-shaped correction capacitance is controlled by turning on / off the FET 1510 to correct horizontal distortion in accordance with the horizontal synchronization frequency.

[0006]

However, in the above-described configuration, in a display such as a recent multi-scan display that supports high frequencies, many S-shaped correction capacitors are switched to correct horizontal distortion. FET is required. In addition, since the correction is performed by switching the capacitance of the capacitor, when the frequency other than the capacitance suitable for the capacitance or the horizontal size is changed, the correction cannot be completed completely, and there is a problem that the display quality is deteriorated.

[0007] The present invention takes into account such problems in conventional distortion correction and takes into account any arbitrary input frequency.
It is another object of the present invention to provide a distortion correction device capable of correcting distortion with high accuracy and a small circuit scale even when the horizontal size is changed.

[0008]

According to the first aspect of the present invention, a horizontal output circuit for generating a deflection current for deflecting an electron beam in a horizontal direction by a horizontal drive pulse, and the generated deflection current are supplied. A horizontal deflection coil, an S-shaped correction capacitor for correcting horizontal distortion, a frequency discrimination circuit for discriminating an input frequency from a horizontal synchronization signal and outputting polarity and amplitude level information of a correction waveform, and a horizontal synchronization signal and a frequency discrimination circuit A parabolic waveform generating circuit that generates a correction waveform for optimally correcting horizontal distortion based on the output of the IGBT, and a correction that superimposes a correction waveform generated by the parabolic waveform generation circuit on a correction waveform generated by the S-shaped correction capacitor. This is a distortion correction device including a waveform superimposing transformer.

The present invention of claim 2 provides the above-mentioned claim 1.
Is a distortion correction device in which the output of the parabolic waveform generation circuit is a correction waveform having an upward convex shape or a downward convex shape whose amplitude level is adjusted according to the input frequency.

According to a third aspect of the present invention, there is provided a horizontal output circuit for generating a deflection current for deflecting an electron beam in a horizontal direction by a horizontal drive pulse, and a horizontal deflection coil to which the generated deflection current is supplied. An S-shaped correction capacitor for correcting horizontal distortion, a frequency discriminating circuit for discriminating an input frequency from a horizontal synchronizing signal and outputting polarity and amplitude level information of a corrected waveform, and an output of the horizontal synchronizing signal and the frequency discriminating circuit. Parabola waveform generation circuit that generates a correction waveform for optimally correcting horizontal distortion, and a horizontal size detection circuit that detects horizontal size and outputs horizontal size information, and outputs a parabola waveform generation circuit based on the horizontal size information An amplitude adjustment circuit for adjusting the amplitude level of the correction waveform to be output, and an output of the amplitude adjustment circuit for the correction waveform generated in the S-shaped correction capacitor. A distortion correction device and a correction waveform superimposed transformer for superimposing a positive waveform.

Further, the present invention of claim 4 provides the above-mentioned claim 3.
Wherein the horizontal size detection circuit detects a change in the peak voltage of the flyback pulse generated by the horizontal output circuit to detect the horizontal size.

The present invention of claim 5 provides the above-mentioned claim 3.
Wherein the horizontal size detection circuit detects a change in the power supply voltage supplied to the horizontal output circuit, thereby detecting the horizontal size.

According to a sixth aspect of the present invention, there is provided a horizontal output circuit for generating a deflection current for deflecting an electron beam in a horizontal direction by a horizontal drive pulse, and a horizontal deflection coil to which the generated deflection current is supplied. An S-shaped correction capacitor for correcting horizontal distortion, a frequency discriminating circuit for discriminating an input frequency from a horizontal synchronizing signal and outputting polarity and amplitude level information of a corrected waveform, and an output of the horizontal synchronizing signal and the frequency discriminating circuit. Parabola waveform generation circuit for generating a correction waveform for optimally correcting horizontal distortion by using a horizontal synchronization signal and an output of a frequency discrimination circuit, an intermediate correction waveform generation circuit, and a parabola waveform generation circuit A superimposing circuit that superimposes the output of the intermediate part and the output of the intermediate part correction waveform generation circuit, and a complement that outputs the correction waveform generated by the S-shaped correction capacitor to the superposition circuit A distortion correction device and a correction waveform superimposed transformer for superimposing the waveform.

The present invention according to claim 7 provides the above-mentioned claim 6.
In the distortion correction device, the output of the intermediate part correction waveform generation circuit is a correction waveform for correcting distortion in the intermediate part of the screen.

According to the present invention, there is provided a horizontal output circuit for generating a deflection current for deflecting an electron beam in a horizontal direction by a horizontal drive pulse, and a horizontal deflection coil to which the generated deflection current is supplied. An S-shaped correction capacitor for correcting horizontal distortion, a frequency discriminating circuit for discriminating an input frequency from a horizontal synchronizing signal and outputting polarity and amplitude level information of a corrected waveform, and an output of the horizontal synchronizing signal and the frequency discriminating circuit. A parabola waveform generating circuit that generates a correction waveform for optimally correcting horizontal distortion, an intermediate portion correction waveform generating circuit that generates a correction waveform from the output of a horizontal synchronization signal and a frequency discrimination circuit, and a vertical synchronization signal. A modulation circuit that generates a modulation waveform in the vertical direction of the screen and modulates the output of the intermediate correction waveform generation circuit, the output of the parabola waveform generation circuit, and the modulation circuit A superimposing circuit for superimposing a force, a strain compensation device that includes a correction waveform superimposed transformer for superimposing an output for correcting waveform of the superimposing circuit in correction waveform generated in the S-correction capacitor.

The present invention according to claim 9 is the invention according to claim 8.
Wherein the modulation circuit is a distortion correction device that generates a waveform for correcting vertical line bending in the middle of the screen.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing an embodiment. (First Embodiment) FIG. 1 is a block diagram of a distortion correcting apparatus according to a first embodiment of the present invention. The distortion correction device shown in FIG. 1 includes an input terminal 100 to which a horizontal drive pulse is supplied, a horizontal output circuit 101, a horizontal deflection coil 102, an S-shaped correction capacitor 103, a correction waveform superimposing transformer 104, a horizontal synchronization signal , A parabolic waveform generating circuit 106, and a frequency discriminating circuit 107.

In FIG. 1, a horizontal output circuit 101 generates a waveform (deflection current) for deflecting an electron beam in a horizontal direction from a horizontal drive pulse supplied to an input terminal 100. The waveform is supplied to the horizontal deflection coil 102, whereby a sawtooth current flows through the horizontal deflection coil 102, and the electron beam is deflected in the horizontal direction.

The S-shaped correction capacitor 103 is for correcting non-linearity in the horizontal direction on the display screen.

The correction waveform superimposing transformer 104 superimposes a correction waveform for correcting distortion that cannot be completely corrected due to horizontal non-linearity corrected by the S-shaped correction capacitor 103.

The parabolic waveform generating circuit 106 generates a correction waveform (parabolic waveform) for adjusting horizontal non-linear distortion from the horizontal synchronizing signal supplied to the input terminal 105. The waveform is supplied to the correction waveform superimposing transformer 104, whereby the correction waveform is superimposed on the correction waveform generated in the S-shaped correction capacitor 103, and the display screen is optimally corrected.

The frequency discriminating circuit 107 has an input terminal 105
The frequency of the input signal is determined from the horizontal synchronization signal supplied to
At 06, the polarity of the correction waveform and the waveform level signal are output.

FIG. 2 is a waveform diagram showing the deviation of the electron beam on the display screen, the correction waveform generated by the S-shaped correction capacitor 103, and the deflection current corrected by the correction waveform.

FIG. 2A shows the relationship between the center of the CRT tube surface and the center of deflection of the electron beam. As shown in FIG. 2A, the center of deflection of the electron beam is shorter than the center of the tube surface of the CRT. The deflected electron beam shifts greatly toward the periphery of the screen.

FIG. 2 (b) shows a waveform at both ends of the S-shaped correction capacitor 103 for correcting the shift in the vicinity thereof, and generates a parabolic waveform as shown in the figure.

FIG. 2C shows an S-shaped correction capacitor 103.
Shows the deflection current corrected by
The dotted waveform is a case where the S-shaped correction is not performed, and the solid-line waveform is a portion corrected by the S-shaped correction capacitor 103, so that the center of the display surface and the electron beam shift amount around the horizontal display surface are substantially equalized. Is done.

FIG. 3 shows the relationship between the input frequency and the voltage across the S-shaped correction capacitor 103. As shown in FIG. 3, when the input frequency increases, the supply voltage (not shown) to the horizontal output circuit 101 increases. Therefore, it is necessary to increase the correction waveform accordingly.

FIG. 4 shows correction waveform diagrams at respective locations when the input frequency is high.

FIG. 4A shows a parabolic waveform generating circuit 10.
6 and the input frequency is high, so that an upwardly convex correction voltage is generated. FIG. 4B shows a waveform at both ends of the S-shaped correction capacitor 103, and FIG. 4C shows a correction waveform (point A in FIG. 1) superimposed by the correction waveform superimposing transformer 104. The output of the waveform generation circuit 106 and the correction waveform of the S-shaped correction capacitor 103 are added.

FIG. 5 shows correction waveform diagrams at respective locations when the input frequency is low.

FIG. 5A shows a parabolic waveform generating circuit 10.
6 and the input frequency is low, so that a downwardly convex correction voltage is generated. 5B shows a waveform at both ends of the S-shaped correction capacitor 103, and FIG. 5C shows a correction waveform (point A in FIG. 1) superimposed by the correction waveform superimposing transformer 104. The output of the waveform generation circuit 106 and the correction waveform of the S-shaped correction capacitor 103 are added.

Next, the operation of the distortion correcting apparatus according to the first embodiment configured as described above will be described with reference to the drawings.

First, the horizontal output circuit 101 is connected to the input terminal 1
00 generates a waveform (deflection current) for deflecting the electron beam in the horizontal direction from the horizontal drive pulse supplied from the horizontal deflection coil 1.
02, whereby a saw-tooth current flows through the horizontal deflection coil 102 to deflect the electron beam in the horizontal direction.

The frequency discriminating circuit 107 has an input terminal 105
The input frequency is determined from the horizontal synchronization signal supplied from
From the determined frequency, the parabolic waveform generation circuit 106
Output the polarity information and the waveform level of the correction waveform necessary for generating the waveform.

Here, as shown in FIG. 2A, since the center of the CRT tube surface and the center of deflection are different, the amount of deflection deflected by the deflection coil becomes larger toward the periphery of the screen. In order to correct this, a correction voltage as shown in FIG. 2B is generated by using the S-shaped correction capacitor 103, and the deflection current of a portion corresponding to the periphery of the display surface as shown by the solid line in FIG. And the non-linearity of the display surface is corrected. The S-curve correction capacitor voltage required to correct the non-linearity of this screen differs depending on the frequency. As shown in FIG. 3, as the input frequency increases, the correction voltage generated across the S-curve correction capacitor 103 needs to be increased. There is.

In order to realize this function, the capacitance value of the S-shaped correction capacitor 103 is fixed to an optimum capacitance value at an intermediate frequency in the inputtable frequency range. Determine the input frequency,
The correction level of the parabola correction waveform and the polarity of the correction waveform required at that frequency are output to the parabolic waveform generation circuit 106. The parabolic waveform generation circuit 106 outputs a correction waveform adjusted to an appropriate polarity and amplitude to the correction waveform superimposing transformer 104 based on the input supplied from the frequency discrimination circuit 107, and adjusts the correction amount.

For example, when the input frequency is high, the input frequency is discriminated by the frequency discriminating circuit 107, and information on the corrected waveform level and the polarity level is output to the parabolic waveform generating circuit 106. The parabolic waveform generation circuit 106 generates an upwardly convex correction waveform as shown in FIG. 4A so that the correction voltage becomes high because the frequency is high.

This correction waveform is supplied to the correction waveform superimposing transformer 1
4 is superimposed on the S-shaped correction capacitor waveform in FIG. 4B, and a correction voltage as shown in FIG. 4C is generated at point A in FIG. As a result, a high voltage correction waveform required when the frequency becomes high is generated, and the deflection current is corrected.
Improve nonlinear distortion.

Conversely, when a low frequency is input, the input frequency is determined by the frequency determination circuit 107, and information on the corrected waveform level and the negative polarity level is output to the parabolic waveform generation circuit 106. The parabolic waveform generation circuit 106 generates a downwardly convex correction waveform as shown in FIG. 5A so that the correction voltage is low because the frequency is low.

This correction waveform is supplied to the correction waveform superimposing transformer 1
4 is superimposed on the S-shaped correction capacitor waveform in FIG. 5B, and a correction voltage as shown in FIG. 5C is generated at point A in FIG. Thus, a correction waveform of a low voltage required when the frequency becomes low is generated.

As described above, according to the present embodiment, the S-shaped correction capacitor 103 has a fixed capacitance value that is optimal at an intermediate frequency in a frequency range that can be input. The generation circuit 106 outputs an upwardly convex correction waveform, and superimposes it on the S-shaped correction capacitor waveform. Conversely, if a frequency lower than the intermediate frequency is input, the parabolic waveform generation circuit 106 outputs a downwardly convex correction waveform. By outputting the correction waveform and superimposing it on the S-shape correction capacitor waveform, a desired correction voltage can be obtained, so that there is no need to arrange an S-shape correction capacitor for each input frequency, thereby reducing the circuit scale and increasing the S-shape. It is not possible to completely correct with the correction capacitor capacity, that is, in the middle of each step when performing correction stepwise by turning on and off the capacitor as in the conventional example. It can be optimally corrected even if the frequency is entered. (Second Embodiment) FIG. 6 is a block diagram of a distortion correction apparatus according to a second embodiment of the present invention, and corresponds to each unit of the first embodiment shown in FIG. The same reference numerals are given to the same parts, and the description thereof will be omitted.

In FIG. 6, a horizontal size detection circuit 601 is provided.
Detects that the horizontal size has been changed, and outputs the size information to the amplitude adjustment circuit 602.

The amplitude adjustment circuit 602 adjusts the correction waveform input from the parabolic waveform generation circuit 106 so as to have the optimum correction waveform amplitude in the display size based on the output of the horizontal size detection circuit 601.

FIG. 7 shows the relationship between the display size and the necessary S-shaped correction voltage. When the display size is reduced as shown in the figure, the S-shaped correction voltage needs to be reduced.

The operation of the distortion correcting apparatus according to the second embodiment configured as described above will be described with reference to the drawings.

First, the horizontal size detection circuit 601 detects that the user or the like has changed the horizontal size, and sets the amplitude adjustment circuit 6 so that the S-shaped correction voltage suitable for the display size is obtained.
02 to output a control signal. In the amplitude adjustment circuit 602,
The output of the horizontal size detection circuit 601 adjusts the amplitude level of the correction waveform output from the parabolic waveform generation circuit 106 to an optimum level.

Here, as a method of detecting the horizontal size, the peak voltage of the flyback pulse voltage generated in the horizontal output circuit 101 at each input frequency or the power supply voltage + B ( (Not shown) and the relationship between the previously measured screen size can be easily achieved.

As described above, according to the present embodiment, the change in the horizontal size is detected by using the peak voltage of the horizontal output pulse and the like, and the amplitude adjustment circuit 602 is adjusted so as to perform the correction corresponding to the horizontal size. By superimposing the correction waveform from, even when the input frequency is the same and the horizontal size changes, the non-linear distortion can be corrected, so that a highly accurate image display can be performed. (Third Embodiment) FIG. 8 is a block diagram of a distortion correction apparatus according to a third embodiment of the present invention, and corresponds to each unit of the first embodiment shown in FIG. The same reference numerals are given to the same parts, and the description thereof will be omitted.

In FIG. 8, an intermediate part correction waveform generation circuit 8
01 generates a correction waveform for correcting the distortion of the middle part of the display screen from the horizontal synchronization signal supplied to the input terminal 105,
This is to output an optimum intermediate distortion correction waveform based on the amplitude level control signal supplied from the frequency determination circuit 107.

The superimposition circuit 802 superimposes the output of the parabolic waveform generation circuit 106 and the output of the intermediate-part correction waveform generation circuit 801 and outputs the result to the correction waveform superposition transformer 104.

FIG. 9 shows the state of the distortion in the middle part of the display screen, and FIG. 9A shows the shift of the electron beam when the distortion correction in the middle part is not performed.

FIG. 9B shows how an electron beam is displayed on an actual screen when the electron beam is shifted as shown in FIG. 9A.

FIG. 9 (c) shows the results of measuring the non-linear distortion of the vertical line interval in the horizontal direction when a vertical line as shown in FIG. 9 (b) is displayed. The plus direction indicates a portion that is longer than the average, and the minus direction indicates a portion that is smaller than the average.

FIG. 10 shows an output waveform diagram of each part. FIG. 10A shows the output of the parabolic waveform generation circuit 106, and FIG.
01 is the output. FIG. 10C shows the output of the superimposition circuit 802, which is a waveform in which the output waveform of the parabolic waveform generation circuit 106 and the output of the intermediate portion correction waveform generation circuit 801 are superimposed. FIG. 10D shows an S-shaped correction capacitor 10.
10 (e) shows the corrected waveform (point A in FIG. 8) superimposed by the corrected waveform superimposing transformer 104, and shows the output of the S-shaped correction capacitor 103 and the output of the superimposing circuit 802. The output has a superimposed waveform.

The operation of the distortion correcting apparatus according to the third embodiment configured as described above will be described with reference to the drawings.

As shown in FIG. 9A, recent CRTs are generally flattened, and distortion in the peripheral portion is reduced by the S-shaped correction capacitor 103 shown in the first embodiment. When the correction is performed so as to be optimal, the correction in the middle part of the display screen is insufficient, and the middle part of the screen is extended. When a vertical line is displayed on the screen in this state, FIG.
As shown in (b), the display is such that the space between the screen middle portions is extended. FIG. 9C shows the nonlinear distortion at this time as a difference from the average interval.

In order to correct the elongation of the intermediate portion, a correction waveform of the opposite polarity having the same shape as the distortion factor shown in FIG. 9C is superimposed on a parabolic waveform generated at both ends of the S-shaped correction capacitor 103. However, the correction can be made by reducing the horizontal shift in the middle part of the screen.

To realize this function, the input terminal 10
5 generates a correction waveform having a polarity opposite to that of the distortion factor graph shown in FIG. 9C from the horizontal synchronizing signal supplied from No. 5, and the input frequency from the frequency information of the frequency discrimination circuit 107. Then, the amplitude level of the correction waveform is adjusted so that the distortion of the intermediate portion becomes optimal, and the correction waveform as shown in FIG.

In the superimposing circuit 802, the parabolic waveform generating circuit 106 generates a correction waveform as shown in FIG. 10A adjusted so that the peripheral portion of the screen is optimized at the input frequency described in the first embodiment. And the correction waveform output from the intermediate part correction waveform generation circuit 801 are superimposed on the output of FIG.
Is output to the correction waveform superimposing transformer 104.

The correction waveform input to the correction waveform superimposing transformer 104 is superimposed on the S-shaped correction capacitor waveform in FIG. 10D, and a correction voltage as shown by a dotted line in FIG. Generate. Thereby, the extension of the middle portion of the screen is corrected.

As described above, according to the present embodiment, the extension of the middle portion of the screen, which occurs when a flat CRT is used, is corrected by the middle portion correction waveform generation circuit 801 to provide high precision from the center to the periphery of the screen. This makes it possible to perform various distortion corrections. (Fourth Embodiment) FIG. 11 is a block diagram showing a distortion correcting apparatus according to a fourth embodiment of the present invention. 3rd shown
The same reference numerals are given to the portions corresponding to the respective portions of the embodiment, and the description will be omitted.

In FIG. 11, a modulating circuit 1102 generates a vertical rate correction waveform for correcting vertical distortion of a middle portion of a screen from a vertical synchronization signal supplied from an input terminal 1101, and generates a middle portion correction waveform generation circuit 801. The amplitude of the correction waveform amplitude level of the horizontal rate for correcting the horizontal distortion supplied from the controller is modulated at the vertical rate.

FIG. 12 shows the state of distortion in the vertical direction in the middle part of the display screen. FIG. 12 (a)
This shows a state in which no correction has been made. If no correction is made as shown in the figure, the vertical line will bend. FIG.
(B) shows a case where, in order to correct this, the horizontal sawtooth current is modulated in the vertical direction, the deflection current is increased at the center in the vertical direction of the screen, and the vertical line in the peripheral part in the horizontal direction of the screen is corrected to be straight. FIG.

FIG. 13 shows a waveform diagram when the intermediate correction waveform is modulated at a vertical rate.

FIG. 14 shows a correction change of the display surface when the intermediate portion correction waveform is corrected at the vertical rate. The vertical line is corrected as shown by the arrow in the figure.

The operation of the distortion correcting apparatus according to the fourth embodiment configured as described above will be described with reference to the drawings.

As shown in FIG. 12A, when the horizontal deflection current is not corrected at the vertical rate, the vertical line is bent due to the difference in the vertical deflection distance from the electron beam emission point. To correct this, the horizontal deflection current is modulated at the vertical rate, the deflection current at the center of the screen in the vertical direction is increased,
The correction is performed so that the vertical line in the peripheral part in the horizontal direction of the screen is straight. However, since recent CRTs are flattened, even if vertical lines are corrected to be straight around the screen due to differences in screen localization, as shown in FIG. Then, the correction is not enough and the vertical line is bent.

In order to correct this, the amount of correction in the middle part in the horizontal direction is controlled for each vertical line, and the amount of correction is increased in the vertical peripheral part of the screen, and reduced in the center part, so that the vertical part of the middle part of the screen is reduced. Line bending can be corrected.

To realize this function, the input terminal 11
01 from the vertical synchronizing signal supplied from the
In FIG. 13B, a downwardly convex waveform whose amplitude changes at a vertical rate as shown in FIG. 13A is created, and the output of the intermediate part correction waveform generation circuit 801 is modulated with this waveform to obtain FIG. A waveform as shown (a dotted line is displayed so that the change in the peak voltage of the correction waveform is easy to understand) is generated and output to the superimposing circuit 802. The superimposing circuit 802 superimposes the intermediate portion correction waveform modulated at the vertical rate and the output of the parabolic waveform generation circuit 106, and outputs the result to the correction waveform superimposing transformer 104.

As a result, the correction level in the middle portion differs for each line of the screen, and the correction amount is large in the peripheral portion perpendicular to the screen and small in the central portion as shown by the arrow in FIG. The vertical line bending of the part is corrected.

As described above, according to the present embodiment, a modulation waveform of a vertical rate is created from a vertical synchronizing signal, and the output of the intermediate portion correction waveform generation circuit 801 is corrected with this correction waveform, whereby the vertical direction 1 Since the correction amount of the screen intermediate portion for each line can be adjusted, a highly accurate screen display can be performed.

As described above, according to the present invention, it is not necessary to switch the S-shaped correction capacitor for correcting the non-linear distortion of the screen in the horizontal output circuit section so as to be optimal depending on the input frequency. Since the horizontal distortion in the middle part of the screen and the vertical line bending in the middle part can be arbitrarily corrected by the middle part correction waveform generation circuit etc., the circuit scale is small and high-precision distortion correction is required. Can be.

By using the method of detecting the change in horizontal size and adjusting the amplitude of the correction waveform described in the second embodiment in the third or fourth embodiment, higher accuracy can be obtained. Needless to say, it is possible to realize a great distortion correction.

[0074]

As is evident from the above description, the present invention provides a highly accurate distortion correction circuit with a small circuit scale at any arbitrary input frequency and even when the horizontal size is changed. It has the advantage that it can be corrected.

Further, according to the present invention, by providing an intermediate portion correction waveform generation circuit and a modulation circuit using a vertical synchronizing signal, horizontal distortion of a screen intermediate portion and vertical lines of the intermediate portion, which are problems in recent flat CRTs, are provided. Since the bending can be arbitrarily corrected, there is an advantage that the circuit scale is small and distortion correction can be performed with high accuracy.

[Brief description of the drawings]

FIG. 1 is a block diagram of a distortion correction device according to a first embodiment of the present invention.

FIG. 2 is an operation waveform diagram showing a shift of an electron beam on a tube surface and a principle of correction by an S-shaped correction capacitor in the first embodiment.

FIG. 3 is a diagram illustrating a relationship between an input frequency and a correction voltage required for an S-shaped correction capacitor according to the first embodiment.

FIG. 4 is an operation waveform diagram when the input frequency is high in the first embodiment.

FIG. 5 is an operation waveform diagram when the input frequency is low in the first embodiment.

FIG. 6 is a block diagram of a distortion correction device according to a second embodiment of the present invention.

FIG. 7 is a diagram showing a relationship between a horizontal size and a correction voltage required for an S-shaped correction capacitor in the second embodiment.

FIG. 8 is a block diagram of a distortion correction device according to a third embodiment of the present invention.

FIG. 9 is a diagram showing a display state of a screen and non-linear distortion in the third embodiment.

FIG. 10 is an operation waveform diagram according to the third embodiment.

FIG. 11 is a block diagram of a distortion correction device according to a fourth embodiment of the present invention.

FIG. 12 is a diagram showing a display state of a screen according to the fourth embodiment.

FIG. 13 is an operation waveform diagram in the fourth embodiment.

FIG. 14 is a diagram showing a correction state on a screen according to the fourth embodiment.

FIG. 15 is a block diagram of a conventional distortion correction device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 100 horizontal drive pulse input terminal 101 horizontal output circuit 102 horizontal deflection coil 103 S-shaped correction capacitor 104 correction waveform superimposing transformer 105 horizontal synchronization signal input terminal 106 parabolic waveform generation circuit 107 frequency discrimination circuit 601 horizontal size detection circuit 602 amplitude adjustment circuit 801 intermediate Section correction waveform generation circuit 802 superposition circuit 1101 vertical synchronization signal input terminal 1102 modulation circuit

Claims (9)

[Claims] 1. A horizontal output circuit for generating a deflection current for deflecting an electron beam in a horizontal direction by a horizontal drive pulse, a horizontal deflection coil to which the generated deflection current is supplied, and correcting a horizontal distortion. An S-shaped correction capacitor, a frequency discriminating circuit that discriminates an input frequency from a horizontal synchronizing signal and outputs polarity and amplitude level information of a corrected waveform, and a horizontal distortion based on the horizontal synchronizing signal and an output of the frequency discriminating circuit. A parabola waveform generating circuit for generating a correction waveform for optimal correction; and a correction waveform superimposing transformer for superimposing a correction waveform generated in the parabolic waveform generation circuit on a correction waveform generated in the S-shaped correction capacitor. A distortion correction device characterized by the above-mentioned. 2. An output of the parabolic waveform generation circuit is an upwardly convex or downwardly convex correction waveform whose amplitude level is adjusted according to the input frequency. The distortion correction device as described. 3. A horizontal output circuit for generating a deflection current for deflecting an electron beam in a horizontal direction by a horizontal drive pulse, a horizontal deflection coil to which the generated deflection current is supplied, and correcting a horizontal distortion. An S-shaped correction capacitor, a frequency discriminating circuit that discriminates an input frequency from a horizontal synchronizing signal and outputs polarity and amplitude level information of a corrected waveform, and a horizontal distortion based on the horizontal synchronizing signal and an output of the frequency discriminating circuit. A parabola waveform generation circuit that generates a correction waveform for optimal correction, a horizontal size detection circuit that detects horizontal size and outputs horizontal size information, and a correction waveform output by the parabola waveform generation circuit based on the horizontal size information. An amplitude adjustment circuit for adjusting an amplitude level; and a compensation output from the amplitude adjustment circuit for a correction waveform generated in the S-shaped correction capacitor. A distortion correction device comprising: a correction waveform superimposing transformer for superimposing a positive waveform. 4. The distortion according to claim 3, wherein the horizontal size detection circuit detects the horizontal size by detecting a change in a peak voltage of a flyback pulse generated by the horizontal output circuit. Correction device. 5. The horizontal size detecting circuit according to claim 3, wherein the horizontal size is detected by detecting a change in a power supply voltage supplied to the horizontal output circuit.
A distortion correction device according to claim 1. 6. A horizontal output circuit for generating a deflection current for deflecting an electron beam in a horizontal direction by a horizontal drive pulse, a horizontal deflection coil to which the generated deflection current is supplied, and correcting a horizontal distortion. An S-shaped correction capacitor, a frequency discriminating circuit that discriminates an input frequency from a horizontal synchronizing signal and outputs polarity and amplitude level information of a corrected waveform, and a horizontal distortion based on the horizontal synchronizing signal and an output of the frequency discriminating circuit. A parabolic waveform generating circuit that generates a correction waveform for optimal correction, an intermediate portion correction waveform generating circuit that generates a correction waveform from the horizontal synchronization signal and an output of the frequency discriminating circuit, and an output of the parabolic waveform generating circuit. A superimposing circuit for superimposing an output of the intermediate part correction waveform generating circuit, and an output of the superimposing circuit on a correction waveform generated in the S-shaped correction capacitor. And a correction waveform superimposing transformer for superimposing a correction waveform to be corrected. 7. An output of the intermediate part correction waveform generation circuit,
7. The distortion correction apparatus according to claim 6, wherein the correction waveform is a correction waveform for correcting distortion in an intermediate portion of the screen. 8. A horizontal output circuit for generating a deflection current for deflecting an electron beam in a horizontal direction by a horizontal drive pulse, a horizontal deflection coil to which the generated deflection current is supplied, and correcting a horizontal distortion. An S-shaped correction capacitor, a frequency discriminating circuit that discriminates an input frequency from a horizontal synchronizing signal and outputs polarity and amplitude level information of a corrected waveform, and a horizontal distortion based on the horizontal synchronizing signal and an output of the frequency discriminating circuit. A parabola waveform generating circuit for generating a correction waveform for optimal correction, an intermediate portion correction waveform generating circuit for generating a correction waveform from the horizontal synchronization signal and the output of the frequency discriminating circuit, A modulation circuit that generates a modulation waveform and modulates an output of the intermediate part correction waveform generation circuit; an output of the parabola waveform generation circuit; And a correction waveform superimposing transformer for superimposing a correction waveform output from the superposition circuit on a correction waveform generated in the S-shaped correction capacitor. 9. The modulation circuit according to claim 8, wherein the modulation circuit generates a waveform for correcting a vertical line curve in an intermediate portion of the screen.
A distortion correction device according to claim 1.