KR100599624B1 - Liquid crystal display and driving method thereof - Google Patents

Abstract

The present invention relates to a liquid crystal display device and a driving method thereof.

According to the present invention, the N-th data stored in the buffer is output while updating the N + 1-th R, G, and B data into the memory. The N + 1st B data is stored in the buffer while the N + 1st R and G data is output.

According to the present invention, the tearing effect can be prevented with a smaller memory.

LCD, Field Sequential, Memory, Tear Effect, Buffer

Description

Liquid crystal display and its driving method {LIQUID CRYSTAL DISPLAY AND DRIVING METHOD THEREOF}

1 is a block diagram of a liquid crystal display according to an exemplary embodiment of the present invention.

2 is an equivalent circuit diagram of one pixel of a liquid crystal display according to an exemplary embodiment of the present invention.

3 is a timing diagram illustrating an operation of a liquid crystal display according to an exemplary embodiment of the present invention.

4 is a block diagram showing an internal configuration of a data driver according to a first embodiment of the present invention.

5 is a block diagram showing an internal configuration of a data driver according to a second embodiment of the present invention.

6 is a flowchart showing the operation of the data driver of the second embodiment.

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device of the field sequential driving method.

Recently, display devices are also required to be lighter and thinner in accordance with the light weight and thickness of personal computers and televisions, and according to such demands, flat panels such as liquid crystal displays (LCDs) instead of cathode ray tubes (CRTs) are required. Display is being developed.

The liquid crystal display device applies an electric field to a liquid crystal material having an anisotropic dielectric constant injected between two substrates, and adjusts the intensity of the electric field to control the amount of light transmitted from the external light source (backlight) to the substrate. It is a display device which obtains a desired image signal.

Such a liquid crystal display is representative of a portable flat panel display, and among these, a TFT-LCD using a thin film transistor (TFT) as a switching element is mainly used.

In general, the liquid crystal display may be classified into two methods, a color filter method and a field sequential driving method, according to a method of displaying a color image.

A color filter type liquid crystal display device forms a color filter layer consisting of three primary colors of red (R), green (G), and blue (B) on one of two substrates, and adjusts the amount of light transmitted through the color filter layer. By doing so, a desired image is displayed. The color filter type LCD synthesizes R, G, and B colors by adjusting the amount of light transmitted through the R, G, and B color filter layers in transmitting light emitted from a single light source to the R, G, and B color filter layers. To display the desired image.

As described above, in a liquid crystal display device that displays an image using a single light source and a three-color color filter layer, a corresponding unit pixel is required for each of the R, G, and B regions, so that three times as many pixels are used as for displaying black and white. It is necessary. Therefore, in order to obtain a high resolution image, sophisticated manufacturing technology of a liquid crystal display panel is required. In addition, such a liquid crystal display device has manufacturing difficulties in that a separate color filter layer is formed on a substrate, and the luminance is lowered because the light transmittance of the color filter itself is low.

The liquid crystal display of the field sequential driving method periodically turns on independent light sources of R, G, and B colors, and applies a color signal corresponding to each pixel in synchronization with the lighting cycle to generate a full color image. Get That is, according to the liquid crystal display of the field sequential driving method, R, G, and B primary colors output from R, G, and B backlights are output to one pixel without dividing one pixel into R, G, and B unit pixels. By displaying the light sequentially in time division, an image is displayed using the afterimage effect of the eye.

Such a field sequential driving method may be classified into an analog driving method and a digital driving method.

The analog driving method sets a plurality of gray voltages corresponding to the number of gray scales to be displayed, selects one gray voltage corresponding to gray data among the gray voltages, and drives the liquid crystal panel with the selected gray voltage to thereby apply the applied gray voltage. The gradation is indicated by the corresponding transmission amount.

On the other hand, in the digital driving method, the driving voltage applied to the liquid crystal is made constant, and the voltage application time is controlled to display the gray scale. According to such a digital driving method, gray scales are displayed by adjusting a cumulative amount of light transmitted through a liquid crystal by maintaining a constant driving voltage and controlling a voltage application state and a voltage non-application state in a timing manner.

In such a liquid crystal display device, when a frame frequency displayed on an image and a frequency of input data are inconsistent with each other, a tearing effect in which two or more types of data (ie, two or more frames of data) are displayed on one screen. Phenomena occur. Due to such a tearing effect, two or more frames of data are divided and displayed on one screen in a color filter type liquid crystal display, and in a field sequential type liquid crystal display, specific R, G, and B colors are used as data of the next frame. It is updated to show a different color, so that a phenomenon such as point noise is observed.

In order to solve this problem, a color filter type liquid crystal display uses a method of changing the frame frequency displayed on the screen at the same speed as the frequency of the input data. However, when the frequency change method is applied to the liquid crystal display of the field sequential method, a problem occurs because it affects the gray scale. In the field sequential liquid crystal display, since a frame is driven by dividing one frame into an R field, a G field, and a B field, a frequency three times faster than that of the color filter method is required. This is because there is a problem with the expression.

SUMMARY OF THE INVENTION The present invention has been made in an effort to solve the above-described problems of the related art, and to provide a liquid crystal display device which prevents point noise caused by a tiering effect.

A liquid crystal display device according to a feature of the present invention for achieving the above object is

A liquid crystal display panel including a plurality of scan lines and a plurality of data lines intersecting the scan lines; A light source sequentially outputting light of a first color, a second color, and a third color to one pixel; A first memory for storing grayscale data, a second memory for storing color data output last in one frame of the grayscale data and having a smaller capacity than the first memory, and being stored in the first memory or the second memory A data driver for outputting data to the data line; And a timing controller configured to process input grayscale data to the data driver, and generate and transmit a signal for controlling an operation of the light source and the data driver, wherein the data driver transmits data to be stored in the first memory. A first signal is controlled to be generated and transmitted to the timing controller.

Here, the timing controller transmits the grayscale data to be stored in the first memory to the first memory only when the first signal is at the first level. In addition, when the first signal is at the first level, the data driver updates the grayscale data transmitted from the timing controller to the first memory and outputs the last color in one frame stored in the second memory. The data of is output to the data line.

On the other hand, when the first signal is at the second level, data stored in the first memory is sequentially output to the data line, and data of the color last outputted in one frame stored in the first memory is output. Transfer to the second memory to store. The first signal is changed to the first level when all data except the data of the color output last in one frame are output to the data line in the grayscale data stored in the first memory.

A method of driving a liquid crystal display according to another feature of the present invention is

A method of driving a liquid crystal display device comprising a plurality of scan lines, a plurality of data lines formed to intersect the scan lines, and a data driver for applying data to the data lines, wherein the data driver stores first grayscale data; A memory, a second memory having a capacity smaller than that of the first memory, the second memory storing grayscale data of a color applied to the data line last in a predetermined period of the grayscale data;

The driving method of the liquid crystal display device,

(a) applying the grayscale data of the Nth period stored in the first memory to the data line; (b) storing, in the second memory, grayscale data of a color last applied among the grayscale data of the Nth period stored in the first memory during the step (a); (c) updating the grayscale data of the N + 1th period to the first memory when all the remaining data except the grayscale data of the color last applied in the step (a) are applied to the data line; And (d) applying to the data line gray level data of a color last applied among the gray level data of the Nth period stored in the second memory during step (c).

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention. Like parts are designated by like reference numerals throughout the specification.

A liquid crystal display and a driving method thereof according to an embodiment of the present invention will now be described in detail with reference to the drawings.

1 is a diagram illustrating a liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 2 is an equivalent circuit diagram of one pixel of the liquid crystal display according to the exemplary embodiment of the present invention.

As shown in FIG. 1, a liquid crystal display according to an exemplary embodiment of the present invention uses a liquid crystal display panel 100, a gate driver 200, a data driver 300, a timing controller 400, and R, G, and B lights. It includes a light emitting diode (500a, 500b, 500c) and the light source controller 600 to output.

The liquid crystal display panel 100 includes a plurality of display signal lines S1 -Sn and D1 -Dm and a plurality of pixels 110, which are connected to the plurality of display signal lines S1-Sn and D1-Dm, and are arranged in a substantially matrix form.

The display signal lines S1 -Sn and D1 -Dm include a plurality of scan lines S1 -Sn for transmitting a gate signal (also referred to as a "scan signal") and data lines D1 -Dm for transmitting a data signal. The scan lines S1-Sn extend substantially in the row direction and are substantially parallel to each other, and the data lines D1-Dm extend substantially in the column direction and are substantially parallel to each other.

Each pixel includes a thin film transistor 10 connected to display signal lines S1 -Sn and D1 -Dm, a liquid crystal capacitor C1, and a storage capacitor Cst connected thereto. Holding capacitor Cst can be omitted as needed.

The thin film transistor 10 is a three-terminal element whose control terminal and input terminal are connected to the scanning line S1-Sn and the data line D1-Dm, respectively, and the output terminal is the liquid crystal capacitor C1 and the storage capacitor Cst. )

The liquid crystal capacitor C1 has a pixel electrode (not shown) and a common electrode (not shown) as two terminals, and the liquid crystal layer between the two electrodes functions as a dielectric. The pixel electrode is connected to the thin film transistor 10 and the common electrode receives a common voltage Vcom.

The storage capacitor Cst is formed by overlapping a separate signal line (not shown) and the pixel electrode, and a predetermined voltage such as the common voltage Vcom is applied to the separate signal line.

In FIG. 2, when the scan signal is applied to the scan line Si and the thin film transistor 10 is turned on, the data voltage Vd supplied to the data line is applied to each pixel electrode through the thin film transistor 10. Then, an electric field corresponding to the difference between the pixel voltage Vp and the common voltage Vcom applied to the pixel electrode is applied to the liquid crystal (equivalently represented by the liquid crystal capacitor in FIG. 2), and thus transmittance corresponding to the intensity of the electric field. To allow light to pass through. At this time, the pixel voltage Vp should be maintained for one frame or one field, and the storage capacitor Cst is used to maintain the pixel voltage Vp applied to the pixel electrode.

Referring back to FIG. 1, the gate driver 200 sequentially applies a scan signal to the scan lines S1 -Sn, thereby turning on the thin film transistor having the gate electrode connected to the scan line to which the scan signal is applied.

The data driver 300 applies a gray voltage corresponding to the gray data R, G, and B data to be input to the data line. Here, the data driver 300 according to the embodiment of the present invention includes a memory for storing the grayscale data (R, G, B DATA) to be input to the R field, G field and B field appropriately, 1 This prevents the tearing effect caused by updating the memory while reading data of the frame from the memory.

The timing controller 400 is an input control signal for controlling gradation data (R, G, B DATA) and its display from an external graphic controller (not shown), for example, a vertical synchronization signal Vsync and a horizontal synchronization signal. (Hysnc) is provided. The timing controller 400 appropriately processes the gray scale data R, G, and B data based on the gray scale data R, G, and B data and the input control signal, according to operating conditions of the liquid crystal display panel 100, and controls the gate. After generating the signal Sg, the data control signal Sd, the light source control signal Sb, and the like, the gate control signal Sg is sent to the gate driver 200 and the data control signal Sd is transmitted to the data driver 300. The gradation data R, G, and B DATA processed by the controller are also exported to the data driver 300 and the light source control signal Sb is sent to the light source controller 600.

The light emitting diodes 500a, 500b, and 500c respectively output light corresponding to R, G, and B to the liquid crystal display panel 100, and the light source controller 600 determines when the light emitting diodes 500a, 500b, and 500c are turned on. To control. At this time, according to the embodiment of the present invention, the timing of supplying the corresponding grayscale data from the data driver 300 to the data line and the timing of turning on the R, G, and B light emitting diodes by the light source controller 600 are the timing controller 400. It can be synchronized by the control signal provided by.

Next, the display operation of the liquid crystal display will be described in detail with reference to FIG. 3.

3 is a timing diagram illustrating an operation of a liquid crystal display according to an exemplary embodiment of the present invention.

As shown in FIG. 3, the liquid crystal display according to the exemplary embodiment of the present invention displays an image by dividing one frame into three fields, that is, an R field, a G field, and a B field. If the drive frequency of one frame is 60 Hz, each field performs display operation in synchronization with 180 Hz. Here, G1, G2, ... Gn represent a scanning signal applied to each gate line, and Cr, Cg, Cb represent a lighting signal for instructing lighting of each of the R, G, and B light emitting diodes 500a, 500b, 500c. Indicates.

One frame of R, G, and B image data supplied from the outside is separated into one frame of R image data, G image data, and B image data by the timing controller 400 to match the display operation of the liquid crystal display device. The converted data is stored in memory (which may be included in the data driver). The image data of each color stored is read out of R image data in an R field period of 1/180 sec divided into three frames in accordance with a read signal from the timing controller 400, followed by G image data in the G field. Subsequently, B image data is sequentially read into the B field.

In the R field, the R image data voltage is sequentially written to all the pixels according to the scan signals G1, G2, ... Gn, and then the light emitting diode 500a is turned on according to the lighting signal Cr in the illumination period. The R image is displayed on the liquid crystal display panel 100.

The G image data voltage is sequentially written to all the pixels according to the scan signals G1, G2, ..., Gn in the writing section of the G field, and then the light emitting diode 500b lights up in accordance with the lighting signal Cg in the lighting section. The G image is displayed on the liquid crystal display panel 100.

The B image data voltage is sequentially written to all the pixels according to the scan signals G1, G2, ..., Gn in the writing section of the B field, and then the light emitting diode 500c lights up in accordance with the lighting signal Cb in the lighting section. The B image is displayed on the liquid crystal display panel 100.

In this way, the image corresponding to each color component of R, G, and B is sequentially displayed for each field of each color of the R, G, and B fields so that the image of the R, G, and B color components is a visual afterimage of human. Is synthesized and visually recognized as a color image of one frame.

In FIG. 3, each field is divided into a writing period and an illumination period to display an image. However, the present invention is not limited thereto, and a reset period for erasing the data voltage applied in the previous field may be separately included.

Hereinafter, a method of properly storing R, G, and B data in a memory in order to solve a tearing effect problem in the liquid crystal display as described above will be described. In the embodiments of the present invention described below, a memory for storing R, G, and G data is described as being included in the data driver 300. However, the present invention is not limited thereto, and the memory is not limited to the timing controller 400 or the like. It can be installed externally.

4 is a block diagram showing an internal configuration of a data driver 300 according to the first embodiment of the present invention. In FIG. 4, only an internal configuration for storing and outputting R, G, and B data in an internal memory of the data driver is illustrated, and other configurations are omitted for convenience.

As shown in FIG. 4, the data driver 300 according to the first exemplary embodiment of the present invention may include a first switching unit 310, a second switching unit 340, a first memory 320, and a second memory 330. ), A controller 350 and a lookup table 360.

The first switching unit 310 stores the R, G, and B data of one frame input from the timing controller 400 in the first memory 420 or the second memory 430 according to the control signal of the control unit 350. Switch to save on. The second switching unit 340 switches to output data stored in the first memory 320 or data stored in the second memory 330 according to the control signal of the controller 350.

In the first and second memories 320 and 330, R, G, and B data of one frame are separately stored and written or read. Here, if the frame data (N-th frame data) to be output to the current frame (N-th frame) is stored and output in the first memory 320, the second memory 330 simultaneously stores the next frame (N + 1). Frame data (N + 1st frame data) to be output is stored in the first frame). Next, when the N + 1 th frame data stored in the second frame memory 330 is output in the N + 1 th frame, the N + second frame data is stored in the first frame memory 320 at the same time. .

The lookup table 360 stores gray voltages corresponding to R, G, and B data, and corresponds to data output from the first memory 320 or the second memory 330 according to a control signal of the controller 350. The gray scale voltage to be outputted to the data line. Here, although the lookup table 360 stores the gray voltage, the gray code corresponding to the R, G, and B data may be stored, and a waveform corresponding to the gray code may be output to the data line.

The controller 450 generates a control signal for controlling the first switch 310, the second switch 340, and the lookup table 360. The controller 450 generates a control signal to read data stored in the second memory 330 while writing the R, G, and B data input to the first memory 420. The first switching unit 310 and the second switching unit 320 are provided. That is, the controller 350 controls the second switching unit 340 to read the N-th frame data stored in the first memory 320 and simultaneously stores the N + 1-th frame data in the second memory 330. To control the first switching unit 310 to. In this case, when the stored frequency is slower than the output frequency, the controller 350 may prevent the Nth frame data stored in the first memory 320 in order to prevent the data from being output before the data is stored in the frame memory. After outputting (reading) the data of the last scan line, the controller checks whether the storage is completed in the second memory 330 and controls to read the frame data stored in the second memory 330 when the storage is completed. Meanwhile, the controller 350 controls the first switching unit 310 to store N + 2th frame data in the first memory 320 after all the data stored in the first memory 320 is read.

According to the data driver according to the first exemplary embodiment of the present invention, since the N + 1th frame data is stored in another memory while the Nth frame data is read, the data of the Nth frame is read and displayed on the liquid crystal display panel. The tearing effect problem caused by updating the N + 1th frame data can be prevented.

However, in the first embodiment of the present invention, when the first and second memories 320 and 330 are frame memories, two frame memories are used, and a large memory capacity is required. Furthermore, when using a liquid crystal display in a window with a mobile phone, there is not enough space for memory. As described with reference to FIG. 3, the liquid crystal display according to the exemplary embodiment of the present invention is driven by dividing one frame into an R field, a G field, and a B field, and thus does not use two frame memories as in the data driver of the first embodiment. It can be used as a memory corresponding to one frame memory and one-third of the frame memory.

FIG. 5 is a block diagram showing an internal configuration of a data driver 300 'according to the second embodiment of the present invention, and FIG. 6 is a flowchart showing an operation process of the data driver 300' of the second embodiment. In FIG. 5, only an internal configuration for storing and outputting R, G, and B data in the memory of the data driver 300 ′ is shown, and other configurations are omitted for convenience.

As shown in FIG. 5, the data driver 400 ′ according to the second embodiment of the present invention may include a memory 310 ′, a buffer 320 ′, a switching unit 330 ′, a controller 340 ′, and a lookup table ( 350 ').

The memory 310 ′ stores R, G, and B data output from the timing controller 400. In this case, the timing controller 400 may update the data by transmitting the R, G, and B data to the memory 310 'only when a WE (Write Enable) signal is transmitted from the controller 340' to 1 (High). have.

The buffer 320 'is a memory having a capacity corresponding to 1/3 of the storage capacity of the memory 310'. In the exemplary embodiment of the present invention, only the B data which is output last in one frame is stored. If the data output to the data line last in one frame is other than the B data, the corresponding data is stored.

The switching unit 330 'switches to read the data stored in either the memory 310' or the buffer 320 'according to the control signal of the controller 340', and then switches the read data to the lookup table 350 '. To send).

 The lookup table 350 'stores the gray scale voltages corresponding to the R, G, and B data, and the data is output from the memory 310' or the buffer 320 'according to the control signal of the controller 340'. The corresponding gray voltage is output to the data line. Here, although the lookup table 350 ′ stores the gray voltage, the digital driving method may store gray codes corresponding to the R, G, and B data, and waveforms corresponding to the gray codes may be stored. Can be output to the line.

The controller 340 ′ generates and outputs a write enable (WE) signal to the timing controller 400, and controls the memory 310 ′, the buffer 320 ′, the switching unit 330 ′, and the lookup table 350 ′. Generates a control signal and transmits each. Here, the controller 340 'generates and outputs a WE signal that is 1 (High) when both the R data and the G data are read and output from the memory 310', and all data stored in the buffer 320 'is output. If is output, generate WE signal which is 0 (Low) and output.

Hereinafter, a method of properly processing the R, G, and B data by the data driver 300 ′ according to the second embodiment having the same configuration will be described in more detail with reference to FIG. 6.

First, it is assumed that the WE signal is set to a state of 0 (Low) at the start time (S100), and it is assumed that N-th R, G, and B data are stored in the memory 310 '. Here, the timing controller 400 may update the data by transmitting the R, G, and B data to the memory 310 'only when a WE (Write Enable) signal, which is 1 (High), is transmitted from the controller 340'. Therefore, the N-th R, G, and B data are not updated in the memory 310 '.

Next, the controller 340 ′ controls the switching unit 330 ′ and transfers the R and G data stored in the memory 310 ′ to the lookup table 350 ′, LUT in order (S200). In this case, the controller 340 'transmits and stores the B data stored in the memory 310' to the buffer 320 '(S200). In general, since the R, G, and B data are sequentially output to the data lines D1 to Dm in one frame, the last output B data is stored in the buffer 320 ', and the R or G data is finally output. In this case, the last outputted data is stored in the buffer 320 '. Then, the controller 340 'reads the gray voltage or waveform corresponding to the gray data output from the memory 310' from the lookup table 350 'and outputs it to the data line.

It is determined whether all of the G data stored in the memory 310 'are transmitted to the lookup table. If all of the G data are not transmitted, the operation S200 is repeated (S300 and S200).

When all the G data stored in the memory 310 is transmitted as a look-up data and the corresponding data is output, the controller 340 'sets the WE signal to' 1 'and transmits it to the timing controller 400 (S300, S400).

At this time, the timing controller 400 transmits the N + 1 th R, G, and B data to be stored in the memory 310 ', and the N + 1 th R to the memory 310' under the control of the controller 340 '. , G, B data is updated (S500).

While the N + 1 th data is updated in the memory 310 ', the controller 340' controls the switching unit 330 'so that the N th B data stored in the buffer 320' is looked up. ') Is transmitted to output the corresponding data (S600). In FIG. 6, step S500 and step S600 are shown as steps before and after time, but the two steps are performed simultaneously.

Next, when all the B data of the buffer 320 'is outputted, the flow returns to step 100 and the WE signal is set to 0 (Low) to repeat the above steps (S600 and S100).

In the above-described embodiment, one frame is divided into R fields, G fields, and B fields by way of example. However, the present invention divides one frame into a plurality of screens, and each screen is divided into R, The same may be applied to the case of driving by dividing into G and B fields. In this case, the grayscale data stored in the memory and the buffer of the above embodiment becomes R, G, and B data applied to each screen.

As described above, according to the second embodiment of the present invention, the N-th B data stored in the buffer 320 'is output while updating the N + 1 th R, G, and B data to the memory 310'. By doing this, the tearing effect can be prevented. In addition, a tearing effect problem can be prevented by using a buffer corresponding to a capacity of 1/3 compared to the first embodiment.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

 As described above, according to the present invention, the N-th data stored in the buffer is output while updating the N + 1-th R, G, and B data to the memory, thereby preventing the tiering effect with a smaller capacity.

Claims (15)

A liquid crystal display panel including a plurality of scan lines and a plurality of data lines intersecting the scan lines; A light source sequentially outputting light of a first color, a second color, and a third color to one pixel; A first memory for storing grayscale data, a second memory for storing color data output last in one frame of the grayscale data and having a smaller capacity than the first memory, and being stored in the first memory or the second memory A data driver for outputting data to the data line; And A timing controller configured to process input grayscale data to the data driver, and generate and transmit a signal for controlling an operation of the light source and the data driver, And the data driver generates a first signal for controlling data to be stored in the first memory and transmits the first signal to the timing controller. The method of claim 1, And the timing controller transmits the grayscale data to the first memory to be stored in the first memory only when the first signal is at a first level. The method of claim 2, When the first signal is at the first level, the data driver updates the grayscale data transmitted from the timing controller to the first memory and outputs data of the color last outputted in one frame stored in the second memory. And a liquid crystal display for outputting the data line. The method of claim 3, And the data driver changes the first signal to a second level when all data of colors stored in the second memory are output. The method of claim 1, The data driver, When the first signal is at the second level, the data stored in the first memory is sequentially output to the data line, and the data of the color that is output last in one frame stored in the first memory is output to the first signal. 2 Liquid crystal display for transferring to memory and storing. The method of claim 5, And the first signal is changed to a first level when all data except the data of the color output last in one frame are output from the grayscale data stored in the first memory. The method according to any one of claims 1 to 6, The data driver A switching unit for switching any one of data stored in the first memory and the second memory to be output to the data line; And And a controller configured to control the first memory, the second memory, and the switching unit. The method of claim 7, wherein And the first signal is generated by the controller. The method according to any one of claims 1 to 6, The capacity of the second memory is substantially 1/3 of the capacity of the first memory. A method of driving a liquid crystal display device comprising a plurality of scan lines, a plurality of data lines formed to intersect the scan lines, and a data driver for applying data to the data lines. The data driver may include a first memory for storing grayscale data, a second memory having a smaller capacity than the capacity of the first memory and storing grayscale data of a color applied to the data line last in a predetermined period of the grayscale data. Include, The driving method of the liquid crystal display device, (a) applying the grayscale data of the Nth period stored in the first memory to the data line; (b) storing, in the second memory, grayscale data of a color last applied among the grayscale data of the Nth period stored in the first memory during the step (a); (c) updating the grayscale data of the N + 1th period to the first memory when all the remaining data except the grayscale data of the color last applied in the step (a) are applied to the data line; and (d) applying to the data line the grayscale data of the color which is last applied among the grayscale data of the Nth period stored in the second memory during the step (c). The method of claim 10, And said predetermined period is a period of one frame. The method according to claim 10 or 11, wherein And the second memory is a buffer and corresponds to 1/3 of the capacity of the first memory. The method of claim 10, The gradation data of the color applied last is blue gradation data. The method of claim 10, The liquid crystal display further comprises a timing controller for transmitting the gray data to the data driver, wherein the timing controller transmits the gray data only when a signal for transmitting the gray data is received from the data driver. Method of driving. The method of claim 10, The liquid crystal display of claim 1, wherein the liquid crystal display sequentially transmits light of a first color, a second color, and a third color to one pixel.

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