KR101961187B1 - Driving circuit for liquid crystal display device and method for driving the same - Google Patents

Abstract

The present invention relates to a liquid crystal display device capable of improving a display quality by compensating a luminance deviation between a top and a bottom of a liquid crystal panel so that a failure due to a voltage reverse phenomenon does not occur while reducing a power consumption by inverting a common voltage level supplied to the liquid crystal panel The present invention relates to a driving apparatus for a liquid crystal display device and a driving method thereof, and more particularly, to a liquid crystal display device which receives a common voltage whose voltage level gradually changes while swinging at first and second voltage levels and displays an image. A common voltage generator for generating the common voltage level so that the swing voltage level gradually changes to a logarithmic curve shape while allowing the common voltage level to swing at the first and second levels every frame; A gate and a data driver for driving the gate and data lines of the liquid crystal panel; And a timing controller for aligning image data input from the outside and supplying the data to the data driver, and generating a gate and a data control signal to control the common voltage supplier, the gate, and the data driver, respectively.

Description

TECHNICAL FIELD [0001] The present invention relates to a driving apparatus for a liquid crystal display device and a driving method thereof. BACKGROUND OF THE INVENTION [0002]

The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device which compensates for a luminance deviation between a top and a bottom of a liquid crystal panel so that a failure due to a voltage reverse phenomenon does not occur while reducing a power consumption by inverting a common voltage level supplied to the liquid crystal panel And to a driving method of the liquid crystal display apparatus and a driving method thereof.

A liquid crystal display device displays an image using electrical and optical characteristics of a liquid crystal. Liquid crystals can have different anisotropic properties depending on the molecular axis and minor axis direction, such as refractive index and dielectric constant, and can easily control the molecular arrangement and optical properties. A liquid crystal display device using the same displays an image by changing the alignment direction of liquid crystal molecules according to the electric field size and adjusting the light transmittance transmitted through the polarizing plate.

The liquid crystal display device includes a liquid crystal panel in which a plurality of pixels are arranged in a matrix form, a gate driver for driving gate lines of the liquid crystal panel, and a data driver for driving the data lines of the liquid crystal panel.

In the liquid crystal display, an inversion driving method such as a frame inversion system, a line inversion system, and a dot inversion system is used to drive pixels of a liquid crystal panel . Among such inversion driving methods, the frame and line inversion methods can further reduce the power consumption as compared with the dot inversion method, and in the case of the dot inversion method, the image with higher image quality .

In recent years, the common voltage level supplied to each pixel of the liquid crystal panel is also inverted while adopting the line inversion or the frame inversion method, thereby improving the image quality while increasing the power consumption reduction effect.

However, although the data voltage supplied to each pixel is sequentially supplied from the first line to the last line of every frame, since the polarity of the common voltage is inverted every frame, the image quality is deteriorated according to the brightness characteristic deviation of the display image . In other words, the polarity of the common voltage is inverted with the beginning of every frame, but the data voltage is supplied sequentially from the first line of every frame. Therefore, coupling phenomenon occurs due to the change in the polarity of the common voltage in the pixels that are charged with the data voltage of the previous frame. In this case, since the charged data voltage level changes, a luminance deviation occurs between the upper and lower ends of the display panel, and image quality defects such as a crosstalk phenomenon occur. In addition, although the drive voltage levels of the liquid crystal panel are varied in order to prevent defects due to luminance variations, in this case, a voltage inversion phenomenon occurs in the central part of the liquid crystal panel in accordance with over compensation, There was no.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems and it is an object of the present invention to provide a liquid crystal display device capable of reducing power consumption by inverting a common voltage level supplied to a liquid crystal panel, And to improve the display quality of the liquid crystal display device, and to provide a driving method thereof.

According to an aspect of the present invention, there is provided a driving apparatus for a liquid crystal display device, comprising: a driving unit for receiving a common voltage whose voltage level is gradually changed while swinging at first and second voltage levels, A liquid crystal panel for displaying; A common voltage generator for generating the common voltage level so that the swing voltage level gradually changes to a logarithmic curve shape while allowing the common voltage level to swing at the first and second levels every frame; A gate and a data driver for driving the gate and data lines of the liquid crystal panel; And a timing controller for aligning image data input from the outside and supplying the data to the data driver, and generating a gate and a data control signal to control the common voltage supplier, the gate, and the data driver, respectively.

The common voltage supply unit receives the reference voltage of the DC level and the rectangular wave swinging every frame unit by the inverting and noninverting terminals and swings at the positive and negative voltage levels every frame, At least one integrating circuit part for outputting a primary voltage so as to be gradually changed in a curved shape and for amplifying the primary voltage to first and second levels of predetermined positive and negative polarities, And at least one differential amplifier for generating the common voltage so that the voltage level gradually changes.

The common voltage supply unit receives the reference voltage of the DC level and the rectangular wave swinging every frame unit by the inverting and noninverting terminals and swings at the positive and negative voltage levels every frame, At least one integrating circuit section for outputting a primary voltage so as to gradually change in a curved shape, a first voltage circuit for amplifying the primary voltage to first and second levels of positive and negative polarities, At least one differential amplifier for generating and supplying a first common voltage to the liquid crystal panel so that the voltage level of the first common voltage gradually changes while swinging the first common voltage and inverting the polarity of the first common voltage generated by the differential amplifier, And at least one inverting circuit for generating a second common voltage whose polarity level is inverted from the common voltage and supplying the second common voltage to the liquid crystal panel .

The first integrating circuit part of the at least one integrating circuit part receives the reference voltage and the swinging square wave respectively through inverting and noninverting terminals and ends at the start of each frame according to the voltage level of the square wave swinging with the reference voltage A first operational amplifier for generating and outputting the primary voltage so that the voltage level gradually increases or decreases to a point in time at which the output voltage of the first operational amplifier is increased or decreased; And a first waveform controller for setting a waveform such that the first voltage level output from the first operational amplifier is gradually increased or decreased through a plurality of resistive elements and a first capacitor formed in a parallel form, do.

Wherein the second integration circuit portion of the at least one integration circuit portion receives the first voltage and the reference voltage from the first integration circuit portion as inverted and noninverted terminals, respectively, A second operational amplifier for converting the waveform of the voltage into a logarithmic curve and outputting the converted waveform, and a second operational amplifier for outputting at least one of a series connection or a parallel connection between the inverting or noninverting terminal of the second operational amplifier and the output terminal of the second operational amplifier And a second waveform controller for setting a waveform such that a voltage level output from the second operational amplifier through the second capacitor is transformed into a logarithmic curve shape.

According to another aspect of the present invention, there is provided a method of driving a liquid crystal display (LCD) device including supplying a common voltage whose voltage level is gradually changed while swinging at first and second voltage levels, A driving method of a liquid crystal display device having a liquid crystal panel for displaying an image, the method comprising: causing the common voltage generator to swing the common voltage level to the first and second levels in units of frames, The method comprising the steps of: Driving the gate and data lines of the liquid crystal panel; And generating a gate and data control signal to control the common voltage supply unit.

The generating of the common voltage includes generating a voltage level swinging at a positive polarity and a negative polarity voltage level every frame based on a DC level reference voltage and a voltage level of a square wave swinging every frame, And amplifying the primary voltage through at least one differential amplifier to a first and a second level of predetermined positive and negative polarities, respectively, so that the first and second And generating the common voltage so that the voltage level gradually changes while swinging to the level.

The generating of the common voltage includes generating a voltage level swinging at a positive polarity and a negative polarity voltage level every frame based on a DC level reference voltage and a voltage level of a square wave swinging every frame, And outputting the first voltage to the first and second levels by amplifying the primary voltage to the first and second levels of the predetermined positive and negative polarities through the at least one differential amplifier, Generating a first common voltage so that the voltage level of the first common voltage gradually changes while supplying the first common voltage to the liquid crystal panel while swinging the first common voltage while at least one inverting circuit is used, And supplying a second common voltage having the polarity level inverted to that of the first common voltage to the liquid crystal panel .

Wherein the step of outputting the primary voltage includes the step of using the first operational amplifier to gradually increase or decrease the voltage level from the start point to the end point of each frame according to the voltage level of the reference voltage and the sweeping square wave, Through the first capacitor and a plurality of resistance elements formed in series or in parallel between the inverting or non-inverting terminal of the first operational amplifier and the output terminal of the first operational amplifier, And setting the waveform so that the voltage level output from the amplifier gradually increases or decreases.

The step of outputting the primary voltage may include transforming a waveform of the primary voltage into a logarithmic curve shape according to a voltage from the first operational amplifier and a level of the reference voltage using a second operational amplifier And a voltage output from the second operational amplifier through at least one resistance element and a second capacitor formed in series or in parallel between the inverting or non-inverting terminal of the second operational amplifier and the output terminal of the second operational amplifier, And setting the waveform so that the level is transformed into a logarithmic curve shape.

A driving apparatus and a driving method of a liquid crystal display according to an embodiment of the present invention having the above-described features reduce power consumption by inverting a common voltage level supplied to a liquid crystal panel, The display image quality can be improved by compensating for the luminance deviation between the upper and lower ends of the liquid crystal panel so that defects do not occur. Further, the common voltage generating and supplying circuit can be simplified by adding the inverting circuit to the circuit portion for generating and supplying the common voltage.

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a circuit diagram showing a driving apparatus of a liquid crystal display according to an embodiment of the present invention; FIG.
Fig. 2 is a configuration circuit diagram schematically showing the common voltage supply unit of Fig. 1; Fig.
FIG. 3 is a configuration circuit diagram implementing the common voltage supply unit of FIG. 2; FIG.
4A and 4B are waveform diagrams showing output waveforms of the first integration circuit shown in FIG. 3;
5A and 5B are waveform diagrams showing output waveforms of the second integration circuit shown in FIG. 3;
6A and 6B are waveform diagrams showing output waveforms of the differential amplifier shown in FIG. 3;
7A and 7B are waveform diagrams showing an output waveform of the differential amplifier section enlarged.
FIG. 8 is another constituent circuit diagram schematically showing the common voltage supply unit of FIG. 1; FIG.
Fig. 9 is a waveform diagram showing an output waveform of the common voltage supply section of Fig. 8 enlarged. Fig.

Hereinafter, a driving apparatus and a driving method of a liquid crystal display according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

1 is a circuit diagram showing a driving apparatus for a liquid crystal display according to an embodiment of the present invention.

The driving apparatus of the liquid crystal display shown in FIG. 1 includes a liquid crystal panel 2 which receives a common voltage SVcom whose voltage level gradually changes while swinging at first and second voltage levels and displays an image, ; A gate driver 6 for driving the gate lines GL1 to GLn of the liquid crystal panel 2; A common voltage generator 10 for generating a swinging voltage level such that the common voltage SVcom level swings to the first and second levels in every frame unit so as to gradually change to a logarithmic curve shape; A data driver 4 for driving the data lines DL1 to DLm of the liquid crystal panel 2; And the image data RGB input from the outside are supplied to the data driver 4 and the gate and data control signals GCS and DCS are generated to be supplied to the common voltage supply unit 10 and the gate and data drivers 6, 4, respectively.

The liquid crystal panel 2 includes a thin film transistor (TFT) formed in each pixel region defined by a plurality of gate lines GL1 to GLn and a plurality of data lines DL1 to DLm, And a capacitor Clc. The liquid crystal capacitor Clc is composed of a pixel electrode connected to the TFT, and a common electrode arranged between the pixel electrode and the liquid crystal. At this time, the common electrode of each pixel region is supplied such that the common voltage SVcom swings in units of frames at the first and second voltage levels, and the voltage level thereof changes in a logarithmic curve shape. On the other hand, the TFT supplies a video signal from each of the data lines DL1 to DLm to the pixel electrode in response to a scan pulse from each of the gate lines GL1 to GLn.

The liquid crystal capacitor Clc charges a difference voltage between the video signal supplied to the pixel electrode and the common voltage SVcom which is varied to the first or second voltage level and varies the arrangement of the liquid crystal molecules according to the difference voltage, The gradation is realized by adjusting the transmittance. At this time, the storage capacitor Cst may be formed by overlapping the pixel electrode with the storage line interposed therebetween, and a parasitic capacitor Cgs may be further formed between the source electrode of the TFT and the gate line GL.

A common voltage, which varies to a first level or a second level, is alternately supplied to each pixel region of the liquid crystal panel 2 in units of frames by a common voltage supply unit (not shown). For example, in the odd frame period, a positive common voltage (+) that varies to a first voltage level is supplied to each pixel region, and a negative common voltage (- May be supplied to the respective pixel regions. At this time, the common voltage varying to the first level or the second level is generated and supplied in such a manner that the voltage level of the log is varied in such a manner that the voltage level is gradually increased or decreased for each frame. Here, the positive voltage (+) of the first voltage level is supplied at the 6V voltage level of the positive polarity level in the odd frame period, and the negative voltage of the second voltage level is supplied to 0V in the even frame period .

The data driver 4 receives a data control signal DCS from the timing controller 8, for example, a source start signal SSP, a source shift clock SSC, a source output enable That is, a video signal, from the timing controller 8 using a source output enable (SOE) signal and an inversion signal (Pol Signal). Specifically, the data driver 4 latches the aligned data Data through the timing controller 8 in accordance with the SSC, and then, in response to the SOE signal, supplies the scan pulses to the gate lines GL1 to GLn And supplies video signals for one horizontal line to each of the data lines DL1 to DLm for each horizontal period. At this time, the data driver 4 selects the positive or negative gamma voltage corresponding to the gradation value of the data Data arranged according to the negative signal from the timing controller 8, and outputs the selected gamma voltage as a video signal And supplies them to the respective data lines DL1 to DLm.

The gate driver 6 sequentially drives the gate lines GL1 to GLn in accordance with the gate control signal GCS from the timing controller 8. [ Specifically, the gate driver 4 outputs a gate start signal (GSP), a gate shift clock (GSC), a gate output enable (GOE) signal Or the like so that the scan pulses of the gate high voltage (VGH) level are sequentially supplied to the gate lines GL1 to GLn. And the gate-low voltage is supplied to the remaining period in which the scan pulse is not supplied.

The common voltage supply unit 10 uses at least one integration circuit unit and at least one differential amplifier unit so that the common voltage SVcom level swings to the first and second levels every frame, And is gradually changed to a logarithmic curve shape. In other words, the common voltage supply unit 10 is configured to swing at positive and negative voltage levels in units of frames using at least one integration circuit unit, while swinging the voltage level to a linear Thereby generating a common voltage. The common voltage supplier 10 uses the at least one differential amplifier to generate a primary common voltage, that is, a logarithmic curve whose voltage level varies and swings the primary common voltage level to a predetermined first and second Amplified to 2 levels and output. The common voltage supply unit 10 of the present invention will be described in more detail with reference to the accompanying drawings.

On the other hand, the timing controller 8 includes a common voltage supply unit 10, which is not shown, according to external video data RGB and a plurality of synchronization signals DCLK, Hsync, Vsync, And the gate driver 6, respectively. Specifically, the timing controller 8 arranges image data (RGB) input from the outside so as to be suitable for driving the liquid crystal panel 2, and supplies the image data to the data driver 4. A gate control signal GCS and a data control signal GCS are generated by using at least one of a synchronizing signal input from the outside, that is, a dot clock DCLK, a data enable signal DE, and horizontal and vertical synchronizing signals Hsync and Vsync DCS, and supplies them to the gate driver 6 and the data driver 4, respectively. At this time, the timing controller 8 supplies an inversion signal (Pol Signal) to the common voltage supply unit 10 and the data driver 4, respectively. That is, the timing controller 8 controls the common voltage supply unit 10 to supply the common voltage SVcom in the inversion every frame, through the inversion signal, The data driver 4 is controlled so that the pixel regions are driven by at least one of a line inversion method, a column inversion method, a frame inversion method, and a dot inversion method.

2 is a schematic circuit diagram showing the common voltage supply unit of FIG. FIG. 3 is a circuit diagram of the common voltage supply unit of FIG. 2. FIG.

The common voltage supply unit 10 shown in FIG. 3 receives a reference voltage Vref of a DC level and a square wave (Veven / Vodd) swinging in units of frames at inverted and non-inverted terminals, At least one integration circuit portion (INT1, TNT2) for outputting a primary voltage so that a swinging voltage level swings at a polarity and a negative voltage level so as to progressively change to a logarithmic curve form, At least one differential amplifier (Amp1) for generating a common voltage (SVcom) such that the voltage level is gradually changed while the first and second levels are swung to the first and second levels by amplifying to the first and second levels of the polarity and the negative polarity, Respectively.

At least one of the integration circuit sections INT1 and TNT2 has a voltage level from the start point to the end point of each frame in accordance with the voltage level difference between the DC level reference voltage Vref and the square wave Veven / And generates and outputs the common voltage SVcom so as to gradually increase or decrease in a logarithmic curve form.

For example, when the first integration circuit unit INT1 receives the reference voltage Vref at the direct current level and the square wave Veven / Vodd that swings at a level lower than the reference voltage Vref, the first integration circuit unit INT1, Generates and outputs a primary voltage whose voltage level gradually decreases. On the other hand, when square waves (Veven / Vodd) swinging to a level higher than the reference voltage (Vref) are inputted, a primary voltage whose voltage level gradually increases is generated and outputted. Thereafter, the second integration circuit TNT2 modifies and outputs the primary voltage gradually increasing or decreasing in the form of a logarithmic curve gradually increasing or decreasing.

The at least one differential amplifying unit Amp1 receives the level of the primary voltage, which is modified and gradually increased or decreased from the second integrating circuit unit TNT2 in a logarithmic curve form, to a first and a second positive and negative polarities, And outputs it as the common voltage SVcom.

Referring to FIG. 3, the first integration circuit INT1 receives the reference voltage Vref of the DC level and the square wave Veven / Vodd swinging at least one frame unit at the inverting and noninverting terminals, A first operational amplifier A1 for generating and outputting a primary voltage such that the voltage level is gradually increased or decreased from the start point to the end point of each frame according to the voltage level of the sweeping square wave Veven / Vodd, And a plurality of resistive elements (R1_2, R1_3) and a first capacitor (C1_3) formed in series or in parallel between the inverting or noninverting terminal of the first operational amplifier (A1) and the output terminal of the first operational amplifier And a first waveform controller for setting a waveform such that the first voltage level output from the first operational amplifier A1 gradually increases or decreases.

The first integration circuit unit INT1 configured as described above, as shown in the following equation,

The minimum voltage level and the maximum voltage level are set according to the DC voltage reference voltage Vref, the swing voltage level of the sweeping square wave Veven / Vodd, and the resistance values of the resistance elements R1_1, R1_2, and R1_3. The slope of the primary voltage waveform, which gradually increases or decreases according to the value of the two resistors (R1_2, R1_3) connected in parallel and the capacitance of the capacitor (C1), is adjusted. In this way, the first integrating circuit INT1 generates and outputs a primary voltage whose voltage level gradually increases or decreases by adjusting the RC time constant to be optimized.

The second integration circuit part INT2 receives the reference voltage Vref of the first integration circuit part INT1 and the reference voltage Vref of the DC level from the first integration circuit part INT1 through the inverting and noninverting terminals and outputs the reference voltage Vref and the level of the primary voltage A second operational amplifier A2 which transforms the waveform of the primary voltage supplied in a gradually increasing or decreasing voltage level into a curve of a logarithmic shape and outputs it, and a second operational amplifier A2 which inverts or non-inverts the second operational amplifier A2, Output voltage from the second operational amplifier A2 through the at least one resistance element R2_2 and the second capacitor C2 formed in series or in parallel between the inverting terminal and the output terminal of the second operational amplifier A2, And a second waveform control unit for setting a waveform to be transformed into a curve shape of the log form.

Here, the output waveform of the primary voltage, which gradually increases or decreases according to the capacitances of the at least one resistance element R 2 _ 2 and the second capacitor C 2 connected in parallel to each other, is adjusted. In this manner, the second integration circuit unit INT2 outputs a linearly deformed primary voltage by adjusting the time constants of the at least one resistance element R2_2 and the second capacitor C2 to be optimized.

The at least one differential amplifying unit Amp1 receives the voltage output from the second operational amplifier A2 and the swinging square wave Veven / Vodd through inverting and non-inverting terminals, respectively, A third operational amplifier A3 for generating the common voltage SVcom such that the voltage level is swept to the first and second levels while being amplified to the first and second levels of the polarity, And at least one resistor element (R3_4) formed between the inverting or non-inverting terminal of the third operational amplifier (A3) and the output terminal of the third operational amplifier (A3) to stabilize the common voltage (SVcom) Respectively.

FIGS. 4A and 4B are waveform diagrams showing output waveforms of the first integration circuit shown in FIG. 3, and FIGS. 5A and 5B are waveform diagrams showing output waveforms of the second integration circuit shown in FIG.

6A and 6B are waveform diagrams showing output waveforms of the differential amplifier shown in FIG. 3, and FIGS. 7A and 7B are waveform diagrams showing output waveforms of the differential amplifier shown in an enlarged scale.

4A and 4B, the first integration circuit INT1 amplifies the output voltage according to the reference voltage Vref of the DC level and the voltage level of the square wave Veven / Vodd swinging at least one frame unit. And generates and outputs a primary voltage such that the voltage level gradually increases or decreases from the start to the end of each frame according to the RC time constant. As described above, the gradually increasing or decreasing output waveform and the slope of the output signal of the first operational amplifier A1 and the output terminal of the first operational amplifier A1 and the inverted or non-inverted terminal of the first operational amplifier A1 form a series (R1_2, R1_3) and the first capacitor (C1).

5A and 5B, the second integration circuit INT2 generates a waveform of a primary voltage whose voltage level gradually increases or decreases according to the level of the reference voltage Vref and the primary voltage, And outputs it. The logarithmically transformed waveform of the logarithmic shape includes at least one resistance element (not shown) formed in series or in parallel between the inverting or non-inverting terminal of the second operational amplifier A2 and the output terminal of the second operational amplifier A2. (R2_2) and the second capacitor (C2).

6A and 6B, the differential amplifier unit Amp1 amplifies the primary voltage from the second integration circuit unit INT2 to the first and second levels of the positive and negative polarities, respectively, And swings to the second level and outputs the voltage level so as to be output in the form of a logarithmic curve.

As shown in detail in FIGS. 7A and 7B, the common voltage SVcom according to the present invention swings in units of frames and is generated and supplied so that the voltage level thereof is changed to a logarithmic curve rather than a straight line . In this case, it is possible to prevent a reversal phenomenon that may occur at the center of the liquid crystal panel 2, thereby reducing defects. That is, the driving apparatus and the driving method of the liquid crystal display according to the present invention can improve the display image quality by compensating for the luminance deviation between the upper and lower ends of the liquid crystal panel 2 so that image quality deficiency due to the reverse phenomenon does not occur. In addition, the common voltage SVcom level supplied to the liquid crystal panel 2 can be inverted to reduce power consumption.

Fig. 8 is another constituent circuit diagram schematically showing the common voltage supply unit of Fig. 1; Fig.

The common voltage supply unit 10 shown in FIG. 8 is a configuration in which an inverting circuit INV is added to the common voltage SVcom output terminal of the common voltage supply unit shown in FIG. Specifically, the common voltage supply unit 10 shown in FIG. 8 receives a reference voltage Vref of a DC level and a rectangular wave Vodd swinging every frame in units of inverted and non-inverted terminals, At least one integration circuit unit (INT1, TNT2) for outputting a primary voltage such that the voltage level swinging at the positive and negative voltage levels while swinging gradually changes in a logarithmic curve form, The first common voltage odd_Svcom is amplified to the first and second levels of the positive polarity and the negative polarity so that the voltage level of the first common voltage odd_SVcom is gradually changed while swinging to the first and second levels, And the first common voltage odd_SVcom received by receiving the first common voltage odd_Svcom generated by the differential amplifying unit Amp1 are supplied to the first and second common amplifying units Amp1 and Amp1, common And having at least one inverting circuit (INV) to be supplied to the liquid crystal panel 2 to generate a pressure (even_SVcom).

As described above, at least one of the integration circuit units INT1 and TNT2 outputs the reference voltage Vref at the start point of each frame in accordance with the voltage level difference between a reference voltage Vref at a DC level and a voltage level of a square wave Veven / And generates and outputs the common voltage SVcom so that the voltage level gradually increases or decreases in a logarithmic curve form.

The differential amplifier (Amp1) receives the level of the primary voltage, which is transformed from the second integration circuit (TNT2) so as to gradually increase or decrease in a logarithmic curve form, to the first and second levels And outputs it as the first common voltage odd_Svcom. At this time, the first common voltage odd_SVcom may be supplied to the common electrodes of the pixels corresponding to odd-numbered gate lines of the liquid crystal panel 2. [

At least one inverting circuit INV receives the first common voltage odd_SVcom generated by the differential amplifier Amp1 and inverts the polarity level of the applied first common voltage odd_SVcom to generate a first common voltage (odd_SVcom) generates a second common voltage (even_SVcom) whose polarity level is inverted. Here, it may be supplied to the common electrode of the pixels corresponding to the even-numbered gate lines of the liquid crystal panel 2.

9 is a waveform diagram showing an output waveform of the common voltage supply section of FIG. 8 enlarged.

As shown in FIG. 9, the common voltage supply unit 10 shown in FIG. 8 receives the first common voltage odd_SVcom generated by the differential amplifying unit Amp1 and the second common voltage odd_SVcom generated from the inverting circuit INV The common voltage (even_SVcom) is further output. The second common voltage (even_SVcom) is inverted from the polarity level of the first common voltage odd_SVcom and is output. Therefore, when the common voltage odd / even_SVcom having different polarities in the odd and even row or column units is supplied, the common voltage supply unit 10 can be arranged in odd and even rows or in columns A common voltage (odd / even_SVcom) having different polarities can be supplied. In other words, when generating the first and second common voltages (odd / even_SVcom) having polarities opposite to each other, the common voltage supply unit 10 is not configured for each of the first and second common voltages odd / even_SVcom The common voltage supply unit 10 may be provided with an inverting circuit INV to generate and supply a common voltage odd / even_SVcom having different polarities to one common voltage supply unit 10. [

Therefore, in the driving apparatus and the driving method of the liquid crystal display apparatus according to the embodiment of the present invention, the luminance deviation between the upper and the lower ends of the liquid crystal panel is compensated for by the voltage reversal phenomenon, It is possible to simplify the common voltage generating and supplying circuit by adding the inverting circuit while improving the image quality.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Will be clear to those who have knowledge of.

Claims (10)

A liquid crystal panel receiving a common voltage whose voltage level gradually changes while swinging at first and second voltage levels and displaying an image;
Wherein the swinging first voltage level gradually increases in a curved shape having a slope of a logarithmic function while allowing the common voltage level to swing at the first and second voltage levels in units of frames, A common voltage supply unit for gradually decreasing the output voltage to a curved shape having a slope of a logarithmic function;
A gate and a data driver for driving the gate and data lines of the liquid crystal panel; And
And a timing controller for supplying image data inputted from the outside to the data driver and for controlling the common voltage supplier, the gate and the data driver by generating gate and data control signals, Device for driving a device. The method according to claim 1,
The common voltage supply unit
The DC level reference voltage and the square wave swinging every frame are input to the inverting and noninverting terminals. The swinging voltage level is swung at the positive and negative voltage levels every frame. At least one integrating circuit portion for outputting a primary voltage so as to be varied, and
Wherein the first voltage level is swung to the first and second voltage levels by amplifying the primary voltage to the first and second voltage levels of the predetermined polarity and the negative polarity and the first voltage level is gradually changed to a curve shape having a logarithmic slope And the second voltage level has at least one differential amplification part for generating the common voltage so as to gradually decrease in a curved shape having a logarithmic slope. The method according to claim 1,
The common voltage supply unit
The DC level reference voltage and the square wave swinging every frame are input to the inverting and noninverting terminals. The swinging voltage level is swung at the positive and negative voltage levels every frame. At least one integrating circuit portion for outputting a primary voltage so as to be variable,
The first voltage level is swept to the first and second voltage levels by amplifying the primary voltage to the first and second voltage levels of the predetermined positive and negative polarities and the first voltage level is a curve shape having a slope of the logarithmic function At least one differential amplifier for generating a first common voltage and supplying the first common voltage to the liquid crystal panel so that the second voltage level gradually decreases in a curved shape having a slope of a logarithmic function,
And at least one inverting circuit for inverting the polarity of the first common voltage generated by the differential amplifying unit to generate a second common voltage whose polarity level is inverted from the first common voltage and supplying the second common voltage to the liquid crystal panel And a driving circuit for driving the liquid crystal display device. The method according to claim 2 or 3,
The first integration circuit portion of the at least one integration circuit portion
The reference voltage and the swinging square wave are input to the inverting and noninverting terminals, respectively, and the voltage level is gradually increased or decreased from the start point to the end point of each frame according to the voltage level of the square wave swinging with the reference voltage. A first operational amplifier for generating and outputting a primary voltage of
A plurality of resistance elements formed in series or in parallel between an inverting or non-inverting terminal of the first operational amplifier and an output terminal of the first operational amplifier, and a first capacitor And a first waveform control unit for setting a waveform so that the voltage level gradually increases or decreases. 5. The method of claim 4,
The second integration circuit portion of the at least one integration circuit portion
The first voltage and the reference voltage from the first integration circuit are input to the inverting and noninverting terminals, respectively, and the waveform of the primary voltage is transformed into a logarithmic curve in accordance with the level of the reference voltage and the primary voltage A second operational amplifier for outputting
The voltage level output from the second operational amplifier through the at least one resistance element and the second capacitor formed in series or in parallel between the inverting or non-inverting terminal of the second operational amplifier and the output terminal of the second operational amplifier And a second waveform control unit for setting a waveform to be transformed into a logarithmic curve shape. There is provided a method of driving a liquid crystal display (LCD) device including a liquid crystal panel that displays an image by receiving a common voltage whose voltage level is gradually changed while swinging at first and second voltage levels,
The common voltage level allows the common voltage level to swing to the first and second levels on a frame-by-frame basis, while the swinging first voltage level progressively increases in a curvilinear shape with a slope of the logarithmic function, Generating a voltage level to decrease in a curvilinear shape with a slope of the logarithmic function;
Driving the gate and data lines of the liquid crystal panel; And
And generating the gate and data control signals to control the common voltage supply unit. The method according to claim 6,
Wherein generating the common voltage comprises:
The voltage level swinging at the positive polarity and the negative voltage level in units of frames according to the reference voltage of the DC level and the voltage level of the square wave swinging every frame unit is changed so that the voltage level swinging gradually changes in a log- ; And
The first voltage level is swung to the first and second voltage levels by amplifying the primary voltage to the first and second voltage levels of predetermined positive and negative polarities through the at least one differential amplifier, And the second voltage level is generated so as to decrease in a curvilinear shape having a slope of a logarithm of the logarithmic function. The liquid crystal display device according to claim 1, Driving method. The method according to claim 6,
Wherein generating the common voltage comprises:
The voltage level swinging at the positive polarity and the negative voltage level in units of frames in accordance with the reference voltage of the DC level and the voltage level of the square wave swinging every frame unit is set so that the voltage level swinging gradually changes in a log- ,
The first voltage level is swung to the first and second voltage levels by amplifying the primary voltage to the first and second voltage levels of predetermined positive and negative polarities through the at least one differential amplifier, Generating a first common voltage to the liquid crystal panel such that the second voltage level is reduced to a curvilinear shape with a slope of the logarithmic function, and the first common voltage is gradually reduced to a curved shape having a slope of
Inverting the polarity of the first common voltage generated by the differential amplification unit using at least one inverting circuit and supplying a second common voltage having a polarity level inverted to the first common voltage to the liquid crystal panel And a driving method of the liquid crystal display device. The method according to claim 7 or 8,
The step of outputting the primary voltage
Generating and outputting the voltage so that the voltage level gradually increases or decreases from the start point to the end point of each frame according to the voltage level of the reference voltage and the square wave swinging using the first operational amplifier;
The voltage level output from the first operational amplifier through the plurality of resistive elements and the first capacitor formed in series or in parallel between the inverted or non-inverted terminal of the first operational amplifier and the output terminal of the first operational amplifier gradually And a step of setting a waveform so as to increase or decrease the gain of the liquid crystal display device. 10. The method of claim 9,
The step of outputting the primary voltage
Transforming a waveform of the primary voltage into a logarithmic curve shape according to a voltage from the first operational amplifier and a level of the reference voltage using a second operational amplifier,
The voltage level output from the second operational amplifier through the at least one resistance element and the second capacitor formed in series or in parallel between the inverting or non-inverting terminal of the second operational amplifier and the output terminal of the second operational amplifier And setting a waveform to be transformed into a logarithmic curve shape.

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