KR100672412B1 - Screen distortion correcting system and method for operating the same - Google Patents

Abstract

The present invention is directed to minimizing picture distortion, comprising: a main capacitor and a plurality of sub capacitors for compensating for picture distortion; A switch controller for outputting switch control signals having different duty cycles in response to the horizontal synchronization signal; And a plurality of switches that receive the switch control signals, respectively, and change the connection between the main capacitor and the sub capacitors according to the received switch control signals.

Deflection Circuits, Correction Capacitors, Switches

Description

SCREEN DISTORTION CORRECTING SYSTEM AND METHOD FOR OPERATING THE SAME}

1 is a view showing a screen distortion compensation system of the present invention

2 is a diagram showing an example of a parabolic signal with a DC voltage added thereto;

3 is a view showing switch control signals output from comparators;

4 is a diagram illustrating signals detected at the contacts CP1, CP2, CP3, and CP4.

5 is a diagram illustrating a waveform incorporating the signals of FIG. 4.

Explanation of symbols on the main parts of the drawings

10: switch control unit 110: photo coupler

120: sawtooth wave generator 130,140,150,160: comparator

R15, R16, R17, R18: Variable resistors TR1, TR2, TR3, TR4: Switch

C21, C23, C25, C27: negative correction capacitor Cs: primary correction capacitor

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, and more particularly, to a screen distortion compensation system and a driving method thereof for an ultra-slim CRT display device.

The cathode ray tube (CRT) of the display device focuses and accelerates the electrons emitted from the R / G / B electron gun and then collides with the R / G / B fluorescent surface through a shadow mask to form pixels. An electric current flows through the deflection coil to form a two-dimensional screen. However, screen distortion occurs due to a deviation between the distance from the electron gun to the center portion of the CRT screen and the distance from the electron gun to the corner portion of the CRT screen. For example, because the distance from the electron gun to the corner of the screen is relatively long, the width of the cross-hatch on the screen is not constant and the sharpness at the corners of the screen is greater than that of the center of the screen. Falls. In addition, pin distortion occurs at the corners of the screen due to the above-described distance deviation. The narrower the gap between the electron gun and the CRT screen, the more severe the picture distortions described above. Therefore, the disadvantage of such a CRT is to limit the distance between the electron gun and the CRT screen and to make the CRT display device ultra slim.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems of the prior art, and an object thereof is to provide a screen distortion compensation system and a method of driving the same, which minimize screen distortion due to a distance deviation from an electron gun to a CRT screen.

According to another aspect of the present invention, there is provided a screen distortion compensation system including: a main capacitor and a plurality of sub capacitors to compensate for screen distortion; A switch controller for outputting switch control signals having different duty cycles in response to the horizontal synchronization signal; And a plurality of switches that receive the switch control signals, respectively, and change the connection between the main capacitor and the sub capacitors according to the received switch control signals.

The switch control unit receives a sawtooth wave signal synchronized with the horizontal synchronizing signal and a parabola signal synchronized with the vertical synchronizing signal and a comparison DC voltage signal, respectively, and the duty cycle is mutually different according to a comparison result of the two signals. A plurality of comparators for outputting the other switch control signals, a transformer for coupling the pulse voltage of the horizontal synchronizing signal, a sawtooth signal generator for modulating the signal output from the transformer into the sawtooth signal, and the comparators And a plurality of resistors respectively adding DC voltages having different voltage levels to the vertical period parabolic signals to be applied.

Each of the switches connects corresponding sub capacitors in parallel when turned on, and connects the parallel connected sub capacitors in parallel with the main capacitor. And, when each of the switches is turned off, the corresponding subcapacitors are turned off.

Another aspect of the present invention relates to a screen distortion compensation system, comprising: a main capacitor for compensating for distortion of an entire screen; A plurality of subcapacitors for compensating for distortion in each area of the screen; A plurality of comparators for outputting switch control signals having different pulse widths based on vertical period parabolic signals and horizontal period sawtooth signal to which DC voltages having different voltage levels are added; And a plurality of switches for receiving the switch control signals, respectively, and changing the connection between the main capacitor and the sub capacitors for each region according to the received switch control signals.

Each of the comparators outputs the switch control signals having different pulse widths according to the levels of the DC voltages added to the vertical period parabolic signals. The comparator generates the switch control signal having a wider pulse width as the level of the DC voltage is higher, and generates the switch control signal having a narrower pulse width as the level of the DC voltage is lower.

According to an aspect of the present invention, there is provided a method of driving a screen distortion compensation system, the method comprising: generating switch control signals having different duty cycles in response to a horizontal synchronization signal; Transmitting the switch control signals to a plurality of switches, respectively; Changing a connection between a main capacitor and a plurality of sub capacitors connected to the switches according to the transmitted switch control signals.

The generating of the switch control signals having different duty cycles may include: generating a sawtooth wave signal synchronized with the horizontal synchronization signal; Generating vertical period parabola type signals to which DC voltages having different voltage levels are added, respectively; Generating the switch control signals having different duty cycles based on the sawtooth signal and the vertical period parabolic signals.

According to another aspect of the present invention, there is provided a method of driving a screen distortion compensation system, the method comprising: generating a sawtooth signal synchronized with a horizontal synchronization signal; Generating vertical period parabolic signals to which DC voltages having different voltage levels are added, respectively; Outputting switch control signals having different pulse widths based on the sawtooth signal and the vertical period parabolic signals; And changing the connection between the main capacitor for compensating for the distortion of the entire screen and the plurality of subcapacitors for compensating for the distortion per region of the screen according to the switch control signals.

The outputting of the switch control signals having different pulse widths may include outputting the switch control signals having different pulse widths according to the levels of the DC voltages added to the vertical period parabolic signals.

The changing of the connection between the main capacitor and the sub capacitors may include connecting the corresponding sub capacitors in parallel when the output switch control signal is at a 'high' level, and paralleling the parallel connected sub capacitors with the main capacitor. And connecting the corresponding subcapacitors in series and connecting the series connected subcapacitors in parallel with the main capacitor when the output switch control signal is at a 'low' level.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram illustrating an example of a screen distortion compensation system according to the present invention. As shown in FIG. 1, the screen distortion compensation system of the present invention includes a switch controller 10. The switch controller 10 receives a horizontal synchronous signal H-SYNC and a vertical period parabola-type voltage, and outputs switch control signals having different duty cycles. Duty cycle refers to the ratio of repeated on time and off time. The switch control unit 10 includes a horizontal pulse transformer (HPT), a sawtooth wave generating unit 120, a photocoupler 110, a plurality of comparators (130, 140, 150, 160).

The horizontal pulse coupling transformer (HPT) receives the horizontal synchronizing signal, and combines and outputs the voltage magnitude of the received horizontal synchronizing signal. The sawtooth wave generator 120 receives a signal output from the horizontal pulse coupling transformer (HPT) and modulates the received signal into a sawtooth wave signal. The period of the sawtooth wave signal coincides with the period of the horizontal synchronization signal.

The light emitting diode of the photocoupler 110 receives a parabola type signal synchronized with the vertical synchronizing signal V-SYNC, converts the received parabola type signal into an optical signal, and outputs the parabola type signal. The phototransistor of the photocoupler 110 receives an optical signal from the light emitting diode and restores the received optical signal to an electrical signal. Here, the photocoupler 110 is used for electrical isolation between input and output.

The signal received by the phototransistor of the photocoupler 110 is passed through a plurality of capacitors CN1, CN2, CN3, CN4 and a plurality of resistors R11, R12, R13, R14 to the + terminals of the comparators 130, 140, 150, and 160. Are input to each. 2 is a diagram illustrating an example of the vertical period parabolic signal to which a DC voltage is added. As shown in FIG. 2, the level of the vertical period parabolic signal to which the DC voltage is added varies depending on the level of the DC voltage. The DC voltage is a voltage obtained by rectifying the pulse output from the horizontal pulse coupling transformer HPT to the diode D1 and the capacitor C30. The plurality of variable resistors R15, R16, R17, and R18 receive the DC voltage, and add DC voltages having different levels to the parabolic signals respectively input to the comparators 130, 140, 150, and 160. For example, the variable resistor R15 adds the highest level of DC voltage to the parabolic signal input to the comparator 130, and the variable resistor R16 is input to the comparator 140. Add the second highest level of DC voltage to the parabolic signal. In addition, the variable resistor R17 adds a third level of DC voltage to the parabolic signal input to the comparator 150, and the variable resistor R18 is the parabolic type input to the comparator 160. Add a fourth level of DC voltage to the signal. The variable resistors R15, R16, R17, and R18 are connected to the horizontal pulse coupling transformer HPT to rectify the pulses output from the horizontal pulse coupling transformer HPT to the diode D1 and the capacitor C30. DC voltage is provided.

The comparators 130, 140, 150, and 160 respectively receive the sawtooth signal through the terminal and the vertical period parabolic signals to which the DC voltages of different levels are added, respectively, through the + terminal. The comparators 130, 140, 150, and 160 compare the received sawtooth signal with the vertical period parabolic signals, respectively, and output pulse-shaped switch control signals CS1, CS2, CS3, and CS4 based on the two signals, respectively. do. As shown in FIG. 3, the pulse width of the switch control signals CS1, CS2, CS3, and CS4 depends on the level of the DC voltages added to the parabolic signals. For example, when the level of the DC voltage added to the parabolic signal input to the comparator 130 is the highest, the comparator 130 outputs the switch control signal CS1 having the largest pulse width. When the level of the DC voltage added to the parabolic signal input to the comparator 160 is the lowest, the comparator 160 outputs the switch control signal CS4 having the smallest pulse width. Since the levels of the DC voltages input to the comparators 130, 140, 150, and 160 are different from each other, the pulse widths of the switch control signals CS1, CS2, CS3, and CS4 output from the comparators 130, 140, 150, and 160 are different from each other. The switch control signals CS1, CS2, CS3, and CS4 output from the comparators 130, 140, 150, and 160 are respectively input to the plurality of switches TR1, TR2, TR3, and TR4.

The switches TR1, TR2, TR3 and TR4 are field effect transistors. The switches TR1, TR2, TR3, and TR4 include a main correction capacitor (or S-capacitor) Cs for compensating for distortion of the entire screen, and a plurality of sub-correction capacitors for compensating distortion for each region of the screen. Connected. For example, the switch TR1 is connected to the negative correction capacitor C21 through a drain, and the negative correction capacitor C21 is connected in parallel with the main correction capacitor Cs. The switch TR2 is connected to the negative correction capacitor C23 through a drain, and the switch TR3 is connected to the negative correction capacitor C25 through a drain. The switch TR4 is connected to the negative correction capacitor C27 through a drain. Each of the sub correction capacitors C23, C25, and C27 is connected in parallel with the main correction capacitor Cs.

The sub-correction capacitors are used to prevent area-specific distortion of the screen. For example, the sub-correction capacitor C21 corrects the distortion in the center left and right areas of the screen together with the main correction capacitor Cs, and the sub-correction capacitor C23 in the next left and right areas of the center area. The distortion is corrected, the sub correction capacitor C25 corrects the distortion in the next left and right areas of the center area, and the sub correction capacitor C27 corrects the distortion in the left and right edge areas of the screen.

4 illustrates signals detected at output terminals CP1, CP2, CP3, and CP4 of the switches TR1, TR2, TR3, and TR4. Referring to FIG. 4, when the switch control signal CS1 applied to the gate of the switch TR1 has a high level, the switch TR1 is turned on. In this case, the negative correction capacitor C21 is connected in parallel with the main capacitor Cs, and the potential of the output terminal CP1 becomes minimum in the T1-T4 section. In the T5 section, since the switch control signal CS1 applied to the switch TR1 is at a 'low' level, the switch TR1 is in an 'off' state. Therefore, the potential of the output terminal CP1 rises. From the T6 section, the potential of the output terminal CP1 drops and when the T7 section reaches, the discharge potential of the main capacitor Cs is lower than the charging potential of the negative correction capacitor C21, so that the diode connected to the switch TR1. Is 'on' and the sub-compensation capacitor C21 is connected in parallel with the main capacitor Cs in the period T7-T10. Therefore, the potential of the output terminal CP1 becomes minimum again.

Since the switch control signal CS2 applied to the gate of the switch TR2 in the period T1-T3 is 'high' level, the switch TR2 is in an 'on' state and the negative correction capacitor C23 is It is connected in parallel with the main capacitor (Cs). At this time, the potential of the output terminal CP2 is minimum. In the period T4-T5, since the switch control signal CS2 applied to the switch TR2 is at a 'low' level, the switch TR2 is in an 'off' state, and the potential of the output terminal CP2 is increased. . From the T6 section, the potential of the output terminal CP2 drops and when the T8 section reaches the discharge potential of the main capacitor Cs lower than the charging potential of the negative correction capacitor C23, the diode connected to the switch TR2. Is 'ON' and the sub-compensation capacitor C23 is connected in parallel with the main capacitor Cs in the period T8-T10.

In the period T1-T2, since the switch control signal CS3 applied to the gate of the switch TR3 is at a 'high' level, the switch TR3 is in an 'on' state, and the sub correction capacitor C25 is in the main state. It is connected in parallel with the capacitor (Cs). In the period T3-T5, since the switch control signal CS3 applied to the switch TR3 is at a 'low' level, the switch TR3 is in an 'off' state, and the potential of the output terminal CP3 is increased. . From the T6 section, the potential of the output terminal CP3 drops and when the T9 section reaches the discharge potential of the main capacitor Cs is lower than the charging potential of the negative correction capacitor C25, so that the diode connected to the switch TR3. Is 'on' and the sub-compensation capacitor C25 is connected in parallel with the main capacitor Cs in the period T9-T10.

In the T1 section, since the switch control signal CS4 applied to the gate of the switch TR4 is at a 'high' level, the switch TR4 is in an 'on' state, and the sub correction capacitor C27 is connected to the main capacitor ( Connected in parallel with Cs). In the period T2-T5, since the switch control signal CS4 applied to the switch TR4 is at a 'low' level, the switch TR4 is in an 'off' state, and the potential of the output terminal CP4 is increased. . From the T6 section, the potential of the output terminal CP4 drops, and when the T10 section reaches, the discharge potential of the main capacitor Cs becomes lower than the charging potential of the negative correction capacitor C27, so that the diode connected to the switch TR4. Is 'on' and the negative correction capacitor C27 is connected in parallel with the main capacitor Cs.

When all of the switches TR1, TR2, TR3, and TR4 are in an 'on' state in the T1 section, the negative correction capacitors C21, C23, C25, and C27 are connected in parallel to each other and the negative correction connected in parallel. Capacitors C21, C23, C25, and C27 are connected in parallel with the main correction capacitor Cs. When all of the switches TR1, TR2, TR3, and TR4 are in an 'off' state in a period T5-T6, the negative correction capacitors C21, C23, C25, and C27 are not connected in parallel to each other. Each of the correction capacitors C21, C23, C25, and C27 is not connected in parallel with the main correction capacitor Cs.

5 shows a waveform incorporating signals from the output terminals CP1, CP2, CP3 and CP4. The signal shown in FIG. 5 is applied to the anode of the CRT to compensate for distortions occurring in the screen.

The present invention is not limited to the above-described configuration, and the number of comparators and switches, the connection relationship between the main correction capacitor and the sub correction capacitor can be variously changed. In addition, the present invention can be applied not only to CRTs used in TVs but also to monitors in which similar distortion occurs.

As described above, the present invention controls the connection relationship between the main correction capacitor (S-capacitor) and the sub correction capacitors allocated for each screen region by using a plurality of switches having different turn-on times, thereby reducing linearity distortion and Internal pin distortion can be compensated for. Therefore, the CRT display device can be made ultra slim.

 Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

Claims (21)

A main capacitor and a plurality of sub capacitors to compensate for picture distortion; A switch controller for outputting switch control signals having different duty cycles in response to the horizontal synchronization signal; And a plurality of switches respectively receiving the switch control signals and changing the connection between the main capacitor and the sub capacitors according to the received switch control signals. The method of claim 1, The switch control unit receives a sawtooth wave signal synchronized with the horizontal synchronizing signal and a parabola type signal synchronized with the vertical synchronizing signal, respectively, and switches the control signals having different duty cycles according to a comparison result of the two signals. And a plurality of comparators for outputting the compensating screens. The method of claim 2, The switch control unit, A transformer for changing a voltage magnitude of the horizontal synchronization signal; And a sawtooth signal generator for modulating the signal output from the transformer into the sawtooth signal. The method of claim 2, And the switch controller further comprises a plurality of resistors for respectively adding DC voltages having different voltage levels to the parabolic signal applied to the comparators. The method of claim 1, And each of the switches connects the corresponding subcapacitors in parallel when the switches are turned on, and connects the connected subcapacitors in parallel with the main capacitor. A main capacitor for compensating for distortion of the entire screen; A plurality of subcapacitors for compensating for distortion in each area of the screen; A plurality of comparators for outputting switch control signals having different pulse widths based on parabolic signals and sawtooth signals to which DC voltages having different voltage levels are added, respectively; And a plurality of switches respectively receiving the switch control signals and changing the connection between the main capacitor and the sub-capacitors according to the received switch control signals, respectively. The method of claim 6, And a sawtooth signal generator for generating the sawtooth signal in synchronization with a horizontal synchronizing signal. The method of claim 6, A photocoupler for receiving the parabolic signal synchronized with the vertical synchronizing signal; And a plurality of resistors for respectively adding the DC voltages having different voltage levels to the parabolic signal received through the photocoupler. The method of claim 6, Each of the switches, when turned on, connects the corresponding subcapacitors in parallel and connects the parallel connected subcapacitors in parallel with the main capacitor. The method of claim 6, And when both of the switches are turned off, the sum of capacitances of the main capacitor and the corresponding sub-capacitors is maximum. The method of claim 6, And each of the comparators outputs the switch control signals having different pulse widths according to the levels of the DC voltages added to the parabolic signals. The method of claim 11, The comparator generates the switch control signal having a wider pulse width as the level of the DC voltage is higher, and generates the switch control signal having a narrower pulse width as the level of the DC voltage is lower. . Generating switch control signals having different duty cycles in response to the horizontal synchronization signal; Transmitting the switch control signals to a plurality of switches, respectively; And changing a connection between a main capacitor and a plurality of sub-capacitors connected to the switches according to the transmitted switch control signals. The method of claim 13, The generating of the switch control signals having different duty cycles may include: Generating a sawtooth wave signal synchronized with the horizontal synchronizing signal; Generating parabola type signals to which DC voltages having different voltage levels are added, respectively; And generating the switch control signals having different duty cycles based on the sawtooth signal and the parabolic signals. The method of claim 13, Changing the connection between the main capacitor and the sub capacitors, And when the switch control signal transmitted to the switch is at the 'high' level, connecting the corresponding subcapacitors in parallel and connecting the parallel connected subcapacitors in parallel with the main capacitor. How to drive the compensation system. The method of claim 13, Changing the connection between the main capacitor and the sub capacitors, When the switch control signal transmitted to the switch is at a 'low' level, connecting the corresponding subcapacitors in series and connecting the series connected subcapacitors in parallel with the main capacitor. How to drive the compensation system. Generating a sawtooth wave signal synchronized with the horizontal synchronizing signal; Generating parabolic signals to which DC voltages having different voltage levels are added, respectively; Outputting switch control signals having different pulse widths based on the sawtooth wave signal and the parabolic signals; And changing a connection between a main capacitor for compensating for distortion of a full screen and a plurality of subcapacitors for compensating for distortion in each area of a screen according to the switch control signals. The method of claim 17, The outputting of the switch control signals having different pulse widths may include: And outputting the switch control signals having different pulse widths according to the levels of the DC voltages added to the parabolic signals. The method of claim 18, The higher the level of the DC voltage outputs the switch control signal having a wider pulse width, The lower the level of the DC voltage outputs the switch control signal having a narrower pulse width, the driving method of the screen distortion compensation system, characterized in that . The method of claim 17, Changing the connection between the main capacitor and the sub-capacitors, When the output switch control signal is at the 'high' level, connecting the corresponding subcapacitors in parallel and connecting the parallel connected subcapacitors in parallel with the main capacitor. Driving method. The method of claim 17, Changing the connection between the main capacitor and the sub-capacitors, When the output switch control signal is at a 'low' level, connecting the corresponding subcapacitors in series and connecting the series connected subcapacitors in parallel with the main capacitor. Driving method.

Images