KR101818463B1 - Liquid crystal display device and driving method thereof - Google Patents

Abstract

The present invention relates to a liquid crystal display device and a driving method thereof that can improve the liquid crystal response speed of a liquid crystal panel using a cholesteric liquid crystal and prevent deterioration of a liquid crystal to further improve a display quality of an image, 1. A liquid crystal display comprising: a liquid crystal panel having a plurality of pixels including a steric liquid crystal to display an image; A data driver for driving the data lines of the liquid crystal panel such that the cholesteric liquid crystals of each pixel are driven in an initial state and a focal conic state for every horizontal period or respectively in an initial state and a homeotropic state for each horizontal period; A gate driver for driving gate lines of the liquid crystal panel; And a timing controller for aligning the image data inputted from the outside according to the driving of the liquid crystal panel and supplying the data to the data driver, and for controlling the gate and the data driver by generating a gate and a data control signal.

Description

TECHNICAL FIELD [0001] The present invention relates to a liquid crystal display (LCD)

The present invention relates to a liquid crystal display device and, more particularly, to a liquid crystal display device and a liquid crystal display device which can improve the liquid crystal response speed of a liquid crystal panel using a cholesteric liquid crystal, 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 the direction of the short axis, 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.

A liquid crystal display 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 data lines of the liquid crystal panel.

Each pixel of the liquid crystal panel implements a desired color by a combination of red, green, and blue sub-pixels that adjust the light transmittance according to a data signal. Each sub-pixel includes a thin film transistor connected to the gate line and the data line, and a liquid crystal capacitor connected to the thin film transistor. The liquid crystal capacitor charges the difference voltage between the data signal supplied to the pixel electrode through the thin film transistor and the common voltage supplied to the common electrode, and drives the liquid crystal according to the charged voltage to adjust the light transmittance.

The liquid crystal used in the liquid crystal panel is largely divided into Smectic liquid crystal, Nematic liquid crystal and Cholesteric liquid crystal depending on the molecular arrangement method. Among them, the cholesteric liquid crystals are formed in a layered structure between the upper and lower substrates. The molecules of the long axis are arranged in equilibrium, and the orientation of the molecular axis alignment is slightly changed between the adjacent layers, helical structure.

These cholesteric liquid crystals are changed into three arrangement states, that is, a planar arrangement, a focal conic arrangement, and a homeotropic arrangement, respectively, according to the charging voltage difference of the liquid crystal capacitors, .

Conventionally, the cholesteric liquid crystal is changed to a flare state represented by a transparent image and a focal conic state indicated by an opaque image, respectively, so that the light transmittance is controlled. However, when displaying an image by changing to a planer state or a focal conic state as in the related art, a time of about 200 ms is required to stabilize the changed liquid crystal to a planer state or a focal conic state. Therefore, There was a constraint to follow.

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 improving the liquid crystal response speed of a liquid crystal panel using a cholesteric liquid crystal, Apparatus and method of the same.

According to an aspect of the present invention, there is provided a liquid crystal display device including a liquid crystal panel having a plurality of pixels including a cholesteric liquid crystal to display an image; A data driver for driving the data lines of the liquid crystal panel such that the cholesteric liquid crystals of each pixel are driven in an initial state and a focal conic state for every horizontal period or respectively in an initial state and a homeotropic state for each horizontal period; A gate driver for driving gate lines of the liquid crystal panel; And a timing controller for aligning the image data inputted from the outside according to the driving of the liquid crystal panel and supplying the data to the data driver, and for controlling the gate and the data driver by generating a gate and a data control signal.

Wherein the data driver supplies the inverted polarity of the video signal in units of subpixels vertically adjacent to the subpixels of the liquid crystal panel in the vertical direction and inverts the polarity of the video signal in the subpixel unit even in the horizontal direction, The image signal of the homeotropic driving level and the video signal polarity of the focal conic driving level are inverted in units of subpixels vertically adjacent to each other in the vertical direction and the video signal of the homeotropic driving level and the focal conic driving signal So that the video signal polarity of the driving level is inverted.

Wherein the data driver sequentially supplies a voltage of a positive homeotropic driving level and a voltage of a negative focal-conic driving level to odd-numbered data lines of each of the data lines in an odd-numbered frame period, Th data lines, a voltage of a negative fulcrankic driving level and a voltage of a homeotropic driving level of positive polarity are sequentially supplied in units of horizontal lines, and a half period of each half period of the odd-numbered frame periods The voltage of the positive homeotropic driving level or the voltage of the negative focal-conic driving level during the remaining 1/2 period after supplying the initializing voltage that allows the cholesteric liquid crystals of each of the pixels to be in the initial state, Is supplied.

Wherein the data driver sequentially supplies voltages of a positive polarity focal-conic driving level and a polarity of homeotropic driving level to the even-numbered data lines among the data lines in an even-numbered frame period, The data lines are sequentially supplied with a voltage of a negative homeotropic driving level and a voltage of a positive polarity focal-conic driving level, and during a half period of each horizontal period of the even-numbered frame period, And supplies the voltage of the positive polarity driving voltage or the voltage of the negative polarity driving level during the remaining 1/2 period after supplying the initializing voltage.

Wherein the data driver includes a respective switching circuit having a plurality of switching elements, wherein the data driver includes a switching circuit for switching between the positive and negative homeotropic driving level voltages in response to the polarity control signals in the data control signal, A focal-conic driving level voltage, and the initialization voltage, and supplies the selected voltage to the corresponding data line as a video signal.

According to another aspect of the present invention, there is provided a method of driving a liquid crystal display, including: displaying an image using a liquid crystal panel including a plurality of pixels including a cholesteric liquid crystal; Driving the data lines of the liquid crystal panel such that the cholesteric liquid crystals of each of the pixels are driven in an initial state and a focal conic state in every horizontal period or in an initial state and a homeotropic state in every horizontal period, respectively; And arranging image data inputted from the outside in accordance with the driving of the liquid crystal panel and supplying the image data to the data driver and controlling the data driver to drive the data lines of the liquid crystal panel by generating a data control signal do.

The driving of the data lines may be performed such that the polarity of the image signal is inverted in units of sub-pixels vertically adjacent to the sub-pixels of the liquid crystal panel in the vertical direction, and the polarity of the image signal is inverted in the sub- A video signal of a homeotropic driving level and a video signal of a focal conic driving level are inverted from each other in units of subpixels vertically adjacent to each other in the vertical direction, And the polarity of the video signal of the signal and the focal-conic driving level is inverted.

The driving of the data lines may include applying a voltage of a positive homeotropic driving level and a voltage of a negative polarity driving level to the odd-numbered data lines among the data lines during the odd- Numbered data lines, a voltage of a negative fulcrankic driving level and a voltage of a homeotropic driving level of positive polarity are sequentially supplied in units of horizontal lines, and a half of the horizontal periods of the odd-numbered frame periods During the 1/2 period, after the cholesteric liquid crystals of each pixel supply an initialization voltage that can be initialized, the voltage of the positive homeotropic driving level or the negative polarity of the negative polarity And a voltage of a driving level is supplied.

The driving of the data lines sequentially supplies voltages of a positive polarity focal-conic driving level and a polarity of a homeotropic driving level to the even-numbered data lines among the data lines in an even-numbered frame period Numbered data lines, a voltage of a negative homeotropic driving level and a voltage of a positive polarity focal-conic driving level are sequentially supplied to the odd-numbered data lines, and a half period And supplies the voltage of the positive polarity driving voltage level or the voltage of the negative polarity driving level during the remaining 1/2 period after supplying the initialization voltage.

The driving of the data lines may include using the switching circuits of the plurality of switching elements to generate the positive and negative homeotropic driving level voltages according to the polarity control signals in the data control signal, A negative polarity driving voltage, a negative polarity driving voltage, a negative polarity driving voltage, a negative polarity driving voltage, a negative polarity driving voltage, and a negative voltage.

The liquid crystal display device and the driving method thereof according to embodiments of the present invention having the above characteristics can improve the liquid crystal response speed of the liquid crystal panel using the cholesteric liquid crystal and can display more dynamically when the moving image is implemented.

Further, power consumption for driving the cholesteric liquid crystal can be reduced, deterioration of the liquid crystal can be prevented, and the display quality of the image can be further improved.

1 is a configuration diagram illustrating a liquid crystal display device according to an embodiment of the present invention;
FIG. 2A illustrates a pixel matrix structure and a driving method in an odd-numbered frame period. FIG.
FIG. 2B is a waveform diagram showing signals supplied to a pixel matrix in odd-numbered frame periods. FIG.
FIG. 3A is a diagram illustrating a pixel matrix structure and a driving method of an even-numbered frame period. FIG.
FIG. 3B is a waveform diagram showing signals supplied to a pixel matrix in an even-numbered frame period. FIG.
FIG. 4 is a diagram illustrating a video signal selection / output method in the data driver shown in FIG. 1;

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

1 is a configuration diagram illustrating a liquid crystal display device according to an embodiment of the present invention.

The liquid crystal display device shown in FIG. 1 includes a liquid crystal panel 2 having a plurality of pixels including a cholesteric liquid crystal to display an image; The data lines DL1 to DLm of the liquid crystal panel 2 are driven so that the cholesteric liquid crystals of each pixel are driven in the initial state and the focal conic state in every horizontal period or in the initial state and in the homeotropic state in every horizontal period, A data driver 4 for driving the data driver 4; A gate driver 6 for driving the gate lines GL1 to GLn of the liquid crystal panel 2; And the image data RGB inputted from outside are aligned to the driving of the liquid crystal panel 2 and supplied to the data driver 4 and the gate and data control signals GCS and DCS, , And a timing controller (8) for controlling the timing controller (4).

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 liquid crystal capacitor (Clc). The liquid crystal capacitor Clc is composed of a pixel electrode connected to the TFT, and a common electrode facing the pixel electrode and the liquid crystal. 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 the difference voltage between the video signal supplied to the pixel electrode and the common voltage supplied to the common electrode, and adjusts the light transmittance by varying the arrangement of the liquid crystal molecules according to the difference voltage. The storage capacitor Cst is connected in parallel to the liquid crystal capacitor Clc so that the voltage charged in the liquid crystal capacitor Clc is maintained until the next data signal is supplied. On the other hand, the storage capacitor Cst is formed by overlapping the pixel electrode with the previous gate line sandwiching the insulating film. Alternatively, the storage capacitor Cst may be formed by overlapping the pixel electrode with the storage line and the insulating film interposed therebetween.

In the present invention, a cholesteric liquid crystal is used to form the liquid crystal capacitors of the respective pixels. The cholesteric liquid crystal according to the present invention may have a focal conic arrangement or homeotropic alignment depending on the charging voltage difference of the liquid crystal capacitors. ) Arrangement state and adjust the light transmittance. In other words, in general, the cholesteric liquid crystal may adjust the light transmittance in a planar arrangement state in addition to a focal conic arrangement or a homeotropic arrangement. In the present invention, in order to improve the response speed of the liquid crystal, a focal conic arrangement or a homeotropic arrangement state To adjust the light transmittance.

The data driver 4 receives a data control signal DCS from the timing controller 8, for example, a source start pulse SSP, a source shift clock SSC, a source output enable SOE (Source Output Enable) signal from the timing controller 8 to an analog voltage, that is, a video signal. Specifically, the data driver 4 latches the data (Data) subjected to the gamma conversion through the timing controller 8 in accordance with the SSC, and supplies a scan pulse to each of the gate lines GL1 to GLn in response to the SOE signal And supplies a video signal for one horizontal line to each of the data lines DL1 to DLm for every one horizontal period to be supplied. At this time, the data driver 4 selects a positive or negative gamma voltage having a predetermined level according to the gradation value of the aligned data Data, and outputs the selected gamma voltage to each of the data lines DL1 to DLm Supply.

The positive or negative gamma voltage levels having a predetermined level are voltage levels at which the cholesteric liquid crystals are changed into a focal conic or homeotropic state. In other words, the data driver 4 outputs the gamma voltages corresponding to the gradation values of the aligned data (Data) among the positive and negative focal-conic voltage levels and the homeotropic voltage levels of positive and negative polarity, respectively Select. And supplies the selected gamma voltages to the respective data lines DL1 to DLm with a video signal.

Here, the data driver 4 supplies an initialization voltage that allows the cholesteric liquid crystals to be in an initialized state during a certain period of each horizontal period to prevent the degradation of the cholesteric liquid crystals of each pixel, And supplies gamma voltages corresponding to the gradation values of the aligned data (Data). For example, the data driver 4 supplies the initialization voltage that can be initialized to the cholesteric liquid crystals of each pixel during a 1/2 period which is half of each horizontal period, A focal conic gamma voltage of positive or negative polarity and a homeotropic gamma voltage of positive or negative polarity respectively corresponding to the gradation values of the data Data. The configuration and method of selectively outputting the gamma voltages to initialize the cholesteric liquid crystals or to change the state to the focal conic state or homeotropic state will be described in detail with reference to the accompanying drawings.

On the other hand, the gate driver 6 outputs a gate control signal GCS from the timing controller 8, for example, a gate start pulse (GSP), a gate shift clock (GSC) Sequentially generates scan pulses in response to a gate output enable (GOE) signal, and sequentially supplies the scan pulses to the gate lines GL1 to GLn. In other words, the gate driver 6 shifts the GSP from the timing controller 8 according to the GSC to sequentially supply a scan pulse, for example, a gate-on voltage to the gate lines GL1 to GLn. Then, the gate-off voltage is supplied during the period when the gate-on voltage is not supplied to the gate lines GL1 to GLn. Here, the gate driver 6 controls the pulse width of the scan pulse in accordance with the GOE signal.

The timing controller 8 arranges image data (RGB) from the outside so as to be suitable for driving the liquid crystal panel 2 and supplies it to the data driver 4. [ The timing controller 8 controls the timing controller 8 using at least one of a synchronous signal input through an external system or the like such as a dot clock DCLK, a data enable signal DE and horizontal and vertical synchronizing signals Hsync and Vsync. And data control signals GCS and DCS and supplies them to the gate and data drivers 6 and 4, respectively, thereby controlling the gate and data drivers 6 and 4. [ Here, the timing controller 8 supplies the initialization voltage that enables the liquid crystals to be in an initialized state during a certain period of the horizontal period, and supplies the initialization voltage corresponding to the gray scale value of the aligned data (Data) At least one of the data control signals DCS may be generated and supplied at a variable rate twice as fast as the data control signal DCS in order to supply the gamma voltages to be supplied. On the other hand, the timing controller 8 controls the timing controller 8 so that the data driver 4 selects the positive or negative gamma voltages, that is, the polarity of the polarity of the positive polarity or the negative polarity, And generates a control signal. And supplies the generated polarity control signals to the data driver 4.

FIG. 2A is a diagram illustrating a pixel matrix structure and a driving method in an odd-numbered frame period, and FIG. 2B is a waveform diagram illustrating signals supplied to a pixel matrix in an odd-numbered frame period.

2A and 2B, the data driver 4 inverts the polarity of an image signal in units of sub-pixels vertically adjacent to the sub-pixels of the liquid crystal panel 2 in the vertical direction, So that the polarity is inverted. At this time, the polarity of the voltage (VH) of the homeotropic driving level and the voltage (VF) of the focal conic driving level is inverted in units of the subpixels vertically adjacent in the vertical direction, and the homeotropic driving level And the polarity of the voltage VF of the focal-conic drive level is inverted. Here, the voltage (VH) of the homeotropic driving level and the voltage (VF) of the focal conic driving level are both supplied as a video signal for driving the liquid crystal.

The data driver 4 applies a voltage of a positive homeotropic driving level to the odd-numbered data lines DL1, DL3, ... of the data lines DL1 to DLn during odd-numbered frame periods (Odd Frame) The negative voltage VH (+) and the negative voltage VF (-) of the focal-conic drive level are sequentially supplied to the even-numbered data lines DL2, DL4, It is possible to sequentially supply the voltage VF (-) of the conical drive level and the voltage VH (+) of the homeotropic drive level of positive polarity in units of horizontal lines.

At this time, as shown in FIG. 2B, the data driver 4 may cause the cholesteric liquid crystals of each pixel to be in an initialized state during a half period which is half of every horizontal period of the odd frame period (Odd Frame) (VH (+)) of the positive homeotropic drive level or the voltage VF (-) of the negative focal-conic drive level for the remaining 1/2 period after supplying the initialization voltage (Pset) do.

If the polarity of the video signal is inverted in units of horizontal periods, the video signal may not be fully charged. In this case, the pixels to be charged may be divided into horizontal lines or vertical lines. Deterioration may occur and display failure may occur. In the present invention, in order to prevent a difference in the charged amount of a video signal from occurring, and to prevent deterioration of the liquid crystal, a reference voltage or a common voltage, which is preset in the data lines (DL1 to DLm) It is possible to supply the voltage (Pset) of the level (Vcom). In other words, by supplying the reference voltage or the common voltage Vcom or the like, which is an intermediate voltage, during the first half period of each horizontal period, the polarity and the voltage level of the video signal are changed more quickly so that the charging amount difference of the video signal is not generated Deterioration of the liquid crystal can be prevented.

In the present invention, the data lines DL1 to DLm charge share techniques may be used in addition to the method of supplying the reference voltage or the common voltage. In other words, after sharing lines and share switches (not shown) for electrically connecting the data lines DL1 to DLm to the data driver 4 and the liquid crystal panel 2, The data lines DL1 to DLm are electrically connected, that is, charge-shared, in the initial half period of the data line DL1 to DLm.

FIG. 3A is a diagram illustrating a pixel matrix structure and a driving method in an even-numbered frame period, and FIG. 3B is a waveform diagram showing signals supplied to a pixel matrix in an even-numbered frame period.

Referring to FIGS. 3A and 3B, in the even frame period, the data driver 4 inverts the polarity of the video signal in units of upper and lower neighboring subpixels, To be inverted. In other words, the polarity of the voltage VH at the homeotropic driving level and the voltage VF at the focal conic driving level are inverted in units of subpixels adjacent in the vertical direction, and the polarity of the homeotropic driving level So that the polarity of the voltage VH and the voltage VF of the focal-conic drive level is inverted.

The data driver 4 applies a voltage of positive polarity to the even-numbered data lines DL2, DL4, ... among the data lines DL1 to DLn during an even-numbered frame period The odd-numbered data lines DL1, DL3, ... are supplied with the negative voltage of the homeotropic driving level VH (-) and the odd-numbered data lines DL1, Level voltage VH (-) and the positive polarity voltage VF (+) at the focal-conic drive level. At this time, as shown in FIG. 3B, the data driver 4 may cause the cholesteric liquid crystals of each pixel to be in an initialized state during a half period which is half of every horizontal period of the even frame period (Even Frame) (VF (+)) of the positive polarity fulcrumic driving level or the voltage (VH (-)) of the negative polarity driving level during the remaining 1/2 period after supplying the initialization voltage Pset do.

During the even frame period, the data lines DL1 to DLm are pre-set in the first half period, which is half of the horizontal period, in order to prevent the charging amount difference of the video signal from being generated. It is possible to supply the reference voltage or the voltage of the common voltage level. To this end, the timing controller 8 supplies the initializing voltage for the initial 1/2 period of each horizontal period and the data corresponding to the gray scale value of the aligned data (Data) It is possible to generate and supply at least one of the data control signals DCS, for example, the SOE signal at a speed twice as fast as that for supplying the gamma voltages.

4 is a block diagram for explaining a video signal selection and output method in the data driver shown in FIG.

As shown in FIG. 4, at least one switching circuit is provided in the data driver 4 of the present invention to select and output a corresponding video signal according to the polarity control signals from the timing controller 8. More specifically, each of the video signal output terminals of the data driver 4 is provided with switching circuits composed of a plurality of switching elements S1 to S4.

The data driver 4 selects the gamma voltages corresponding to the gradation values of the aligned data (Data) among the positive and negative focal-conic voltage levels and the homeotropic voltage levels of the positive and negative polarities, respectively At this time, each switching circuit composed of the plurality of switching elements S1 to S4 selects the corresponding gamma voltage or initialization voltage Pset according to the polarity control signals and supplies them to the corresponding data lines DL1 to DLm as image signals, respectively do.

Referring to Table 1 above, the polarity control signals from the timing controller 8 can be generated to control all of the switching elements S1 to S4 of the respective switching circuits. Accordingly, as shown in Table 1, the data driver 4 generates the gamma voltages corresponding to the gradation values of the aligned data (Data) in response to the polarity control signals, that is, the focal conic gamma voltages of the positive polarity and the negative polarity, And supplies a selected gamma voltage or initialization voltage (Pset) of the positive and negative polarity homeotropic gamma voltages to the corresponding data lines DL1 to DLm as image signals.

As described above, in the present invention, to improve the response speed of the cholesteric liquid crystal quickly, positive and negative gamma voltages are generated so that the cholesteric liquid crystal can be changed only in a focal-conic arrangement or a homeotropic arrangement. In order to prevent deterioration of the liquid crystal, an initialization voltage Pset such as a reference voltage or a voltage of a common voltage level set in advance is supplied to the data lines DL1 to DLm during an initial 1/2 period which is half of each horizontal period . Accordingly, the present invention improves the liquid crystal response speed of a liquid crystal panel using a cholesteric liquid crystal, and can dynamically display a moving image. Further, power consumption for driving the cholesteric liquid crystal can be reduced, deterioration of the liquid crystal can be prevented, and the display quality of the image can be further improved.

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. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

Claims (10)

1. A liquid crystal display comprising: a liquid crystal panel having a plurality of pixels including a cholesteric liquid crystal to display an image;
A data driver for driving the data lines of the liquid crystal panel such that the cholesteric liquid crystals of each pixel are driven in an initial state and a focal conic state for every horizontal period or respectively in an initial state and a homeotropic state for each horizontal period;
A gate driver for driving gate lines of the liquid crystal panel; And
And a timing controller for controlling the gate and the data driver by supplying image data inputted from outside in accordance with driving of the liquid crystal panel to the data driver and generating a gate and a data control signal, In the apparatus,
The data driver
The polarity of the video signal is inverted in units of sub-pixels vertically adjacent to each sub-pixel in the vertical direction and the polarity of the video signal is inverted in units of sub-pixels even in the horizontal direction,
The image signal of the homeotropic driving level and the video signal polarity of the focal conic driving level are inverted in units of subpixels vertically adjacent to each other in the vertical direction, And the polarity of the video signal of the conical drive level is inverted. delete The method according to claim 1,
The data driver
During odd-numbered frame periods, odd-numbered data lines are sequentially supplied with a voltage of a positive homeotropic driving level and a voltage of a negative polarity driving level in units of horizontal lines, and even- The voltage of the negative fulcrum driving level and the voltage of the positive homeotropic driving level are sequentially supplied in units of horizontal lines,
During the half period of each horizontal period of the odd-numbered frame period, the cholesteric liquid crystals of each pixel supply an initialization voltage that can be initialized, A voltage of a meotropic drive level or a voltage of a negative focal-conic drive level is supplied to the liquid crystal display device. The method of claim 3,
The data driver
Numbered data lines are sequentially supplied with voltages of a positive polarity focal-conic driving level and a negative polarity driving level during the even-numbered frame periods, and the odd-numbered data lines The voltage of the homeotropic driving level of the negative polarity and the voltage of the positive polar fulcrum driving level are sequentially supplied,
During a half period of each horizontal period of the even-numbered frame period, after the initialization voltage is supplied, the voltage of the positive polarity fulcrum driving level or the polarity of the negative polarity driving Level voltage is supplied to the liquid crystal display panel. 5. The method of claim 4,
The data driver
Each of the switching circuits comprising a plurality of switching elements is provided, and in response to the polarity control signals of the data control signal, the homeotropic driving level voltages of the positive and negative polarities, the positive and negative polarity driving voltages A voltage, and an initialization voltage, and supplies the at least one voltage to the corresponding data line as a video signal. Displaying an image using a liquid crystal panel including a plurality of pixels including a cholesteric liquid crystal;
Driving the data lines of the liquid crystal panel such that the cholesteric liquid crystals of each of the pixels are driven in an initial state and a focal conic state in every horizontal period or in an initial state and a homeotropic state in every horizontal period, respectively; And
And controlling the data driver to drive the data lines of the liquid crystal panel by arranging image data inputted from outside in accordance with driving of the liquid crystal panel and supplying the data to the data driver and generating a data control signal A method of driving a liquid crystal display device,
The step of driving the data lines
The polarity of the video signal is inverted in units of sub-pixels vertically adjacent to each sub-pixel in the vertical direction and the polarity of the video signal is inverted in units of sub-pixels even in the horizontal direction,
The image signal of the homeotropic driving level and the video signal polarity of the focal conic driving level are inverted in units of subpixels vertically adjacent to each other in the vertical direction, And the polarity of the video signal of the conical drive level is inverted. delete The method according to claim 6,
The step of driving the data lines
During odd-numbered frame periods, odd-numbered data lines are sequentially supplied with a voltage of a positive homeotropic driving level and a voltage of a negative polarity driving level in units of horizontal lines, and even- The voltage of the negative fulcrum driving level and the voltage of the positive homeotropic driving level are sequentially supplied in units of horizontal lines,
During the half period of each horizontal period of the odd-numbered frame period, the cholesteric liquid crystals of each pixel supply an initialization voltage that can be initialized, And supplying a voltage of a meotropic drive level or a voltage of a negative focal-conic drive level. 9. The method of claim 8,
The step of driving the data lines
Numbered data lines are sequentially supplied with voltages of a positive polarity focal-conic driving level and a negative polarity driving level during the even-numbered frame periods, and the odd-numbered data lines The voltage of the homeotropic driving level of the negative polarity and the voltage of the positive polar fulcrum driving level are sequentially supplied,
During a half period of each horizontal period of the even-numbered frame period, after the initialization voltage is supplied, the voltage of the positive polarity fulcrum driving level or the polarity of the negative polarity driving Level voltage is supplied to the liquid crystal display panel. 10. The method of claim 9,
The step of driving the data lines
Wherein each of the switching circuits including a plurality of switching elements is used to adjust the homeotropic driving level voltage of the positive and negative polarities and the focal conic driving level voltage of the positive and negative polarities according to the polarity control signals in the data control signal, And at least one of the initialization voltages is selected and supplied to the corresponding data lines as a video signal.

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