KR20050115039A - Liquid crystal display and driving method thereof - Google Patents

Abstract

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

According to the present invention, the scan control signal and the light source control signal for controlling the R, G, and B light to be sequentially applied to sequentially apply the scan signal to the scan line for applying the gray scale data are generated by the same timing controller and synchronized with each other. do.

As such, the scan control signal and the light source control signal are generated at the same timing controller, so that the synchronization is well synchronized with each other, thereby enabling accurate color display.

Description

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

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device and a driving method thereof, and more particularly, to a liquid crystal display device having a field sequential driving method and a driving method thereof.

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 displays such as liquid crystal displays (LCDs) instead of cathode ray tubes (CRTs) are required. Display is being developed.

An LCD 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 to the substrate from an external light source (backlight). A display device for obtaining an image signal.

Such LCDs are typical of portable flat panel displays, and among them, TFT-LCDs using thin film transistors (TFTs) as switching devices are mainly used.

In the TFT-LCD, each pixel may be modeled as a capacitor having a liquid crystal as a dielectric, that is, a liquid crystal capacitor. The equivalent circuit of each pixel in the LCD is shown in FIG. 1.

As shown in FIG. 1, each pixel of the liquid crystal display device has a common voltage and a drain electrode of a TFT 10 and a TFT 10 having a source electrode and a gate electrode connected to a data line Dm and a scan line Sn, respectively. And a storage capacitor Cst connected to the drain electrode of the TFT.

In FIG. 1, when the TFT 10 is turned on by being a scan signal to the scan line Sn, the data voltage Vd supplied to the data line is applied to each pixel electrode (not shown) through the TFT. 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. 1), and thus transmittance corresponding to the intensity of the electric field. To allow light to pass through. In this case, the pixel voltage Vp should be maintained for one frame or one field. In FIG. 1, the storage capacitor Cst is used to maintain the pixel voltage Vp applied to the pixel electrode.

In general, the liquid crystal display may be divided 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 transmits the amount transmitted through the color filter layer. Display the desired color by adjusting. In the color filter type LCD, the light emitted from a single light source is transmitted to the R, G, and B color filter layers by adjusting the amount of light transmitted through the R, G, and B filter layers to synthesize R, G, and B colors. Display the desired color.

As described above, in a liquid crystal display device displaying a color 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. need. Therefore, in order to obtain a high resolution image, sophisticated manufacturing technology of a liquid crystal display panel is required.

In addition, there is a manufacturing problem that a separate color filter layer must be formed on the liquid crystal display substrate, and there is a problem that the light transmittance of the color filter itself must be improved.

In the liquid crystal display of the field sequential driving method, independent light sources of R, G, and B colors are periodically turned on sequentially, and a color signal corresponding to each pixel is applied in synchronization with the lighting cycle to produce a full color image. Get it. That is, according to the liquid crystal display of the field sequential driving method, the R, G, and B primary colors output from one of the R, G, and B backlights to one pixel are not divided into R, G, and B unit pixels. By displaying the light sequentially in time division, a color image is displayed using the afterimage effect of the eye.

The field sequential driving method can be classified into an analog 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 data among the gray voltages, and drives the liquid crystal panel with the selected gray voltage, thereby applying the applied gray voltage. Gradation display is performed with the corresponding amount of transmitted light.

2 is a diagram illustrating a driving voltage and a transmitted light amount according to a conventional LCD driving apparatus. In FIG. 2, the driving voltage refers to a voltage applied to the liquid crystal and the optical tranmittance refers to a transmission ratio with respect to the applied light when light is applied to the liquid crystal. That is, the light transmittance refers to the degree of twist that the liquid crystal can transmit light.

Referring to FIG. 2, in the R field section Tr for displaying the R color, a driving voltage of the V11 level is applied to the liquid crystal so that light corresponding to the driving voltage of the V11 level passes through the liquid crystal. In the G field section Tg for displaying the G color, a driving voltage of the V12 level is applied so that light corresponding to the driving voltage of the V12 level passes through the liquid crystal. Then, in the B field section Tb for displaying the B color, a driving voltage of the V13 level is applied to obtain a light transmittance corresponding to the driving voltage of the V13 level. The desired color image is displayed by the sum of the lights of R, G, and B transmitted in the Tr, Tg, and Tb sections, respectively.

On the other hand, the digital driving method makes the driving voltage applied to the liquid crystal constant and controls the voltage application time to perform gradation display. According to this digital driving method, the gray scale is displayed by adjusting the accumulated amount of light transmitted through the liquid crystal by maintaining the driving voltage constant and controlling the voltage applied state and the non-applied state in a timely manner.

FIG. 3 is a waveform diagram illustrating a conventional method for driving a liquid crystal display device of a digital driving method, and illustrates a waveform of a driving voltage according to driving data of a predetermined bit and a light transmittance of the liquid crystal.

Referring to FIG. 3, grayscale waveform data corresponding to each grayscale is provided as a digital signal of a predetermined bit, for example, 7bit, and a grayscale waveform corresponding to the 7bit data is applied to the liquid crystal. Then, the light transmittance of the liquid crystal is determined according to the applied gradation waveform to perform gradation display.

According to the conventional field sequential driving method, when the scan signals are sequentially applied to the scan lines, the corresponding R, G, and B backlight light sources must be driven in synchronization, but they may not be synchronized with each other, thereby preventing accurate gray scale display. That is, when the backlight light source is not turned on when a scan signal is applied from the first scan line to an arbitrary scan line and the backlight light source is turned on after the arbitrary scan line, a scan line in which the backlight light source is not turned on cannot correctly display color gradation. Occurs.

4 is a diagram illustrating a liquid crystal display device according to a conventional field sequential driving method.

As shown in FIG. 4, the conventional liquid crystal display device includes a liquid crystal display panel 10, a scan driver 20, a data driver 30, a gray voltage generator 40, a timing controller 50, and a reset voltage. The generator 600 includes light emitting diodes 60a, 60b, and 60c and a light source controller 70 for outputting R, G, and B light sources, respectively.

Here, in the conventional liquid crystal display, the timing controller 50 and the light source controller 70 do not share timings with each other, and thus, the timing at which the scan signal is applied to the scan line when R, G, and B grayscale data is applied, and the R and G The light emitting point of the B light emitting diodes 60a, 60b, and 60c is not synchronized, which may cause a problem. That is, the timing may not be shared with each other, which may cause a problem that the scan signal and the R, G, and B emission signals are not synchronized.

That is, the timing controller 50 receives the gray level data signals R, G, and B data, the horizontal synchronization signal Hsync, the vertical synchronization signal Vsync, the data application area signal DE, and the main clock MCLK. The necessary control signals Sg and Sd are supplied to the scan driver 20 and the data driver 30, respectively, and the gray scale data R, G, and B data are supplied to the gray voltage generator 400. Here, the data application area signal DE is a signal indicating an area where data is output, and the main clock MCLK is a clock signal which is input from a microprocessor (not shown) and becomes a reference signal.

On the other hand, the light source controller 70 receives the light source control signal Sb generated from the microprocessor and controls the lighting timing of the R, G, and B light emitting diodes 60a, 60b, and 60c.

At this time, since the light source control signal Sb for controlling the light source controller 70 is generated through the main clock MCLK independently of the control signals Sg and Sd output from the timing controller 50, the control signal Sg. , Sd) may cause problems. That is, as described above, when each of the R, G, and B grayscale data is applied, the start time of sequentially applying the scan signal to the scan line and the time of applying the R, G, B backlight light source are not synchronized. May occur. This problem occurs not only in the analog driving method but also in the digital driving method.

The technical problem to be solved by the present invention is to solve the above problems of the prior art, the field sequential driving method of synchronizing the time when the scanning signal is sequentially applied and the time when the R, G, B backlight light source to emit light, respectively It is to provide a liquid crystal display device.

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

A method of driving a liquid crystal display device comprising a liquid crystal formed between a first substrate on which a first electrode is disposed and a second substrate on which a second electrode is disposed, and sequentially transmitting red, green, and blue light to one pixel. To

(a) generating a first control signal for applying the scan signal to the second electrode in response to the grayscale data applied to the first electrode, and applying a scan signal to the second electrode in response to the first control signal; Doing; And

(b) generating a second control signal to apply the light corresponding to the grayscale data, and applying the light while the scan signal is applied;

The first control signal and the second control signal are generated from the same input signal and are synchronized with each other. In this case, a time point at which the first scan signal is applied to the second electrode to apply the gray scale data and a start time point at which the light corresponding thereto is output are identical.

According to another aspect of the present invention,

In the form of a matrix having a plurality of scan lines for transmitting a scan signal, a plurality of data lines insulated from and intersecting the scan lines, a region surrounded by the scan lines and data lines, and switching elements connected to the scan lines and data lines, respectively. A liquid crystal display panel including a plurality of pixels arranged;

A scan driver for sequentially supplying scan signals to the scan lines;

A light source sequentially outputting red, green, and blue light to one pixel;

A data driver for outputting grayscale data of red, green, and blue to the data lines, respectively;

By using a plurality of input signals, a first control signal for controlling to sequentially apply the scan signal to apply the gray scale data to the data line is generated and output to the scan driver, and outputs the first control signal to the scan driver. And a timing controller configured to generate a second control signal that is synchronized and controls to sequentially apply the red, green, and blue light to the light source. Here, when the first scan signal is applied to the second electrode to apply the gray level data of each of the red, green, and blue signals by the first control signal, and the respective red by the second control signal, The starting time point at which the green and blue light is output is the same.

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.

In the following description, the 'gradation voltage' refers to a voltage having different voltage levels, and the 'gradation waveform' refers to a waveform having different magnitudes of an on voltage and an off voltage width. In addition, the scan control signal refers to a signal for controlling the driving of the scan line, and the emission control signal refers to a signal for controlling light emission of the light source.

First, a driving method according to a first embodiment of the present invention will be described with reference to FIGS. 5 and 6. The driving method according to the first exemplary embodiment of the present invention is a diagram illustrating a method in which an scanning control signal for controlling driving of a scanning line and an emission control signal for emitting a backlight light source are synchronized with each other in an analog field sequential driving method.

FIG. 5 is a diagram illustrating a method of driving a field sequential liquid crystal display according to a first exemplary embodiment of the present invention.

As shown in FIG. 5, according to the first embodiment of the present invention, the R field, the G field, and the B field for displaying light corresponding to R, G, and B may be reset periods (Rreset, Greset, and Breset), respectively. It consists of data sections (Rdata, Gdata, Bdata).

The reset periods are sections in which reset voltages are applied to make the state of the liquid crystal by the gray scale displayed immediately before the same state (black state).

The data sections Rdata, Gdata, and Bdata are sections for applying a gradation voltage corresponding to the gradation to be currently displayed, and sequentially turn on a backlight for outputting light corresponding to R, G, and B in the data section. According to the first embodiment of the present invention, a scan signal is applied to each scan line S1, S2, S3 ..... Sn in the data section Rdata, Gdata, Bdata and corresponds to R, G, and B. The backlight for outputting light is sequentially turned on in synchronization with this. After all scan signals are applied, the backlight is turned off, and in FIG. 5, the backlight is continuously turned on for a while after all the scan signals are applied, and then turned off, which gives a time for causing the gray level corresponding to the last scan line to be emitted. For that. That is, in the data period, while the scan signal is applied to all the scan lines, the corresponding backlight is synchronized to generate the control signal sequentially. Hereinafter, a detailed method of causing the backlight to be synchronized while the scan signal is applied will be described.

6 is a diagram illustrating a liquid crystal display according to a first exemplary embodiment of the present invention. 6 is a diagram illustrating a liquid crystal display device in which a scan control signal for applying a scan signal to a scan line and a light emission control signal for applying a light source light signal are synchronized.

As shown in FIG. 6, the liquid crystal display according to the first exemplary embodiment of the present invention includes a liquid crystal display panel 100, a scan driver 200, a data driver 300, a gray voltage generator 400, a timing controller ( 500), light emitting diodes 600a, 600b, and 600c that output R, G, and B light sources, respectively, and a light source controller 700.

A plurality of scan lines are formed on the liquid crystal display panel 100 to transmit a gate-on signal, and are insulated from and intersect with the plurality of scan lines and transmit data data of gray level data corresponding to gray data (not shown). ) Is formed. The plurality of pixels 110 arranged in a matrix form are surrounded by scan lines and data lines, and each pixel includes a thin film transistor (not shown) and a thin film in which a gate electrode and a source electrode are connected to the scan line and the data line, respectively. A pixel capacitor (not shown) and a storage capacitor (not shown) are connected to the drain electrode of the transistor.

The scan driver 200 sequentially applies a scan signal to the scan line, thereby turning on the TFT to which the gate electrode is connected to the scan line to which the scan signal is applied. In this case, according to the first exemplary embodiment of the present invention, the scan control signal Sg controlling the scan driver 200 sequentially emits the R, G, and B LEDs 600a, 600b, and 600c. While the control signal Sg is synchronized with each other, while the R light emitting diode 600a is ON and the scan signal corresponding to the G data is applied while the scan signal corresponding to the R data is applied by the control signals. The B light emitting diode 600c is turned on while the G light emitting diode 600b is turned on and a scan signal corresponding to the B data is applied.

The timing controller 500 is provided with the gray scale data signals R, G, and B data, the horizontal sync signal Hsync, the vertical sync signal Vsync, the data application area signal DE, and the like from an external or graphic controller (not shown). The main clock MCLK is input to supply the necessary control signals Sg, Sd, and Sb to the scan driver 200, the data driver 300, and the light source controller 800, respectively, and the grayscale data R, G, and B. Data) is supplied to the gray voltage generator 400. Here, the data application area signal DE is a signal indicating an area where data is output, and the main clock MCLK is a clock signal that is input from a microprocessor (not shown) and becomes a reference signal.

At this time, according to an embodiment of the present invention, the timing controller 500 receives the plurality of signals, and the scan control signal Sg and the light source controller 800 which control the scan driver 200 to transmit the scan signal. Control the light emission control signal Sb and the data driver 300 to apply the R, G, and B grayscale data to the data line so as to control the R, G, and B light emitting diodes 600a, 600b, and 600c to emit light sequentially. To generate a data control signal Sd. Here, the scan control signal Sg, the light emission control signal Sb, and the data control signal Sd have the same start time information. That is, the start time information includes start time information and scan time corresponding to G gray data such that a start time at which a scan signal corresponding to the R gray data is sequentially applied and a start time at which the R LED 600a emits light are the same. Start time at which the signal is sequentially applied and start time at which the G light emitting diode 600b emits light are the same. Start time at which the scan signal corresponding to the B gray level data is sequentially applied and the B light emitting diode 600c. Start time information that causes a start time point at which light is emitted. In addition, start time information at the start time for applying the respective R, G, and B data to the data line is also synchronized. When control signals Sd and Sb including only the same start time information are transmitted to the data driver 300 and the light source controller 700, respectively, the time and the end at which each of the R, G, and B LEDs terminate light emission. The time point at which the scan signal is applied to the scan line may be determined through the clock in the data driver 300 and the light source controller 700. In addition, end time information that is information about an end time point may be included in the control signals Sg and Sb generated by the timing controller 500.

The gray voltage generator 400 generates a gray voltage having a magnitude corresponding to gray data and supplies it to the data driver 300. The data driver 300 applies the gray voltage output by the gray voltage generator 400 to the data line corresponding to the data control signal synchronized with the embodiment of the present invention.

The light emitting diodes 600a, 600b, and 600c respectively output light corresponding to R, G, and B to the LCD panel, and the light source controller 800 controls the lighting timing of the light emitting diodes 600a, 600b, and 600c. In this case, according to an exemplary embodiment of the present invention, when the scan driver 200 applies a scan signal to the corresponding grayscale data from the data driver 300 and the light source controller 800, R, G, and B The time point at which the light emitting diode is turned on is synchronized by the control signals Sg and Sb provided by the timing controller 500.

Next, a driving method according to a second embodiment of the present invention will be described with reference to FIGS. 7 and 8. The driving method according to the second embodiment of the present invention relates to a driving method of a liquid crystal display device to which the digital field sequential driving method is applied.

7 is a diagram illustrating a method of driving a field sequential liquid crystal display according to a second exemplary embodiment of the present invention.

As shown in FIG. 7, according to the second embodiment of the present invention, the R field, the G field, and the B field for displaying light corresponding to R, G, and B are each divided into a plurality of screen sections (14 screens). Is done. The plurality of screen sections include a reset section (Reset, Greset, Breset) (1 screen) and a data section (Rdata) (2 screen to 14 screen) for applying data. The 2 screens to 14 screens corresponding to the data section are sections separated for applying a different voltage application time to the same voltage for digital driving. The screen is a scanning signal on the first scan line. Indicates the period from which the signal is applied until the scan signal is applied to the last scan line. Here, two screens (2 screens) to 14 screens (14 screens) are applied with the same voltage, respectively, and each pixel is selected from two screens to 14 screens in response to the gray scale data, and gray levels are represented.

The sections corresponding to one screen 1scren, which are reset sections, are sections in which reset waveforms are applied in order to make the state of the liquid crystal by the gray level displayed immediately before the same state (black state). In this reset period, the R, G, and B light emitting diodes 600a, 600b, and 600c are turned off and do not emit light.

The data sections Rdata, Bdata, and Gdata (2 screens to 14 screens) are sections for applying a gradation waveform corresponding to the gradation to be currently displayed, and sequentially turn on a backlight for outputting light corresponding to R, G, and B in this data section. Turn on According to the second embodiment of the present invention, R, G, and B in a section in which 2 screens to 14 screens of each of the R, G, and B fields to which the gray waveform corresponding to the gray scale data is applied are applied. The light emitting diodes are sequentially turned on in synchronization with this. That is, in two screens 14 through 14 screens to which the gray waveform corresponding to the R data is applied, all the scanning lines are applied with the scanning signal and the R LED is turned on in synchronization with it. The same applies to the G field and the B field as shown in FIG. In other words, while the scan signal is applied to all the scan lines in the interval for applying the gray scale data, the control signal is generated such that the backlight is sequentially turned on in synchronization with the scan signal. Meanwhile, in FIG. 7, the R, G, and B light emitting diodes are turned on after turning off the 14th screen (14screeen), respectively, in order to give time for the grayscale corresponding to the last scan line to emit light.

8 is a diagram illustrating a liquid crystal display according to a second exemplary embodiment of the present invention. 8 is a diagram illustrating a liquid crystal display device in which a scan control signal for applying a scan signal to a scan line and a light emission control signal for applying a light source light emitting signal are synchronized in a section in which data is applied. The same parts as the liquid crystal display according to the first embodiment of the present invention shown in FIG. 6 are denoted by the same reference numerals among the liquid crystal display according to the second embodiment shown in FIG. .

In FIG. 8, the gray waveform generator 800 generates a gray waveform having a voltage width corresponding to the gray data and supplies the gray waveform to the data driver 300. The data driver 300 applies the gray waveform output by the gray waveform generator 800 to the data line.

Here, the timing controller 500 also generates the scan control signal Sg, the light emission control signal Sb, and the data control signal Sd similarly to the first embodiment, and is synchronized with each other. However, in the second exemplary embodiment, scanning signals corresponding to 2 screens to 14 screens are applied in 2 screens to 14 screens included in the data sections Rdata, Gdata, and Bdata to which grayscale data is applied. The control signals Sg, Sb, and Sd are generated in the timing controller 500 so that the R, G, and B light emitting diodes 600a, 600b, and 600c light up sequentially. A detailed method for this is easily omitted by those skilled in the art through the first embodiment and will be omitted below.

As described above, in the first and second embodiments of the present invention, the signal controlling the data driver 300, the signal controlling the scan driver 200, and the light source controller 700 are driven through the timing controller 500 to be shared. Since the signals are generated and output individually, they are well synchronized with each other to allow accurate color display.

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 scan control signal for outputting the scan signal and the emission control signal for emitting the R, G, and B backlights are generated together in the timing controller, whereby mutual control signals are synchronized. It is well made to allow accurate color display.

1 is a view showing a pixel of a conventional TFT-LCD.

2 is a waveform diagram illustrating a driving method of a conventional analog liquid crystal display device.

3 is a waveform diagram illustrating a driving method of a conventional digital liquid crystal display device.

4 is a diagram illustrating a liquid crystal display device according to a conventional field sequential driving method.

FIG. 5 is a diagram illustrating a method of driving a field sequential liquid crystal display according to a first exemplary embodiment of the present invention.

6 is a diagram illustrating a liquid crystal display according to a first exemplary embodiment of the present invention.

7 is a diagram illustrating a method of driving a field sequential liquid crystal display according to a second exemplary embodiment of the present invention.

8 is a diagram illustrating a liquid crystal display according to a second exemplary embodiment of the present invention.

Claims (10)

A method of driving a liquid crystal display device comprising a liquid crystal formed between a first substrate on which a first electrode is disposed and a second substrate on which a second electrode is disposed, and sequentially transmitting red, green, and blue light to one pixel. To (a) generating a first control signal for applying the scan signal to the second electrode in response to the grayscale data applied to the first electrode, and applying a scan signal to the second electrode in response to the first control signal; Doing; And (b) generating a second control signal to apply the light corresponding to the grayscale data, and applying the light while the scan signal is applied; And the first control signal and the second control signal are generated from the same input signal and are synchronized with each other. The method of claim 1, And a start point at which a first scan signal is applied to the second electrode to apply the gray scale data and a start point at which light corresponding thereto is output. The method of claim 2, And corresponding light is applied while a last scanning signal is applied to the second electrode to apply the gray scale data. The method according to claim 1 or 2, And the light is always output correspondingly during all sections in which a scan signal is applied to the second electrode to apply the gray scale data. The method according to claim 1 or 2, And the light is not output during a reset period of initializing the liquid crystal state to a specific state. The method according to claim 1 or 2, The voltage applied to the data electrode in correspondence with the grayscale data is a voltage having a different value according to the grayscale data. The method according to claim 1 or 2, The voltage applied to the data electrode corresponding to the gray scale data is the same voltage level according to the gray scale data and its application time is different. In the form of a matrix having a plurality of scan lines for transmitting a scan signal, a plurality of data lines insulated from and intersecting the scan lines, a region surrounded by the scan lines and data lines, and switching elements connected to the scan lines and data lines, respectively. A liquid crystal display panel including a plurality of pixels arranged; A scan driver for sequentially supplying scan signals to the scan lines; A light source sequentially outputting red, green, and blue light to one pixel; A data driver for outputting grayscale data of red, green, and blue to the data lines, respectively; By using a plurality of input signals, a first control signal for controlling to sequentially apply the scan signal to apply the gray scale data to the data line is generated and output to the scan driver, and outputs the first control signal to the scan driver. And a timing controller for generating a second control signal to be synchronized and sequentially outputting the red, green, and blue light to the light source. The method of claim 8, When the first scan signal is applied to the second electrode to apply the gray level data of each of the red, green, and blue signals by the first control signal, and the respective red, green, and the like by the second control signal, The starting point at which blue light is output is the same. The method of claim 8, The light of each of the red, green, and blue is always output correspondingly during all sections in which a scan signal is applied to the second electrode to apply the gray, green, and blue data of the respective red, green, and blue colors. Liquid crystal display.