KR20050053847A - Liquid crystal display and driving method thereof - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device and a driving method thereof, the liquid crystal display device comprising a plurality of pixels each including a first subpixel and a second subpixel, and a gate on / off voltage at a gate line. A gate driver configured to turn on / off the thin film transistor included in the pixel, and receive a video signal from an external device so as to apply a gamma signal corresponding to the video signal so that different data voltages are applied to the first subpixel and the second subpixel. And a data driver configured to apply different data voltages to the first subpixel and the second subpixel, respectively, according to the generated signal controller and the gamma signal from the signal controller. According to the present invention, side visibility can be improved without lowering the white luminance.

Description

Liquid crystal display and driving method thereof {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 and a driving method thereof for adjusting a gamma curve in order to improve visibility.

A general liquid crystal display device includes two display panels and a liquid crystal layer having dielectric anisotropy interposed therebetween. An electric field is applied to the liquid crystal layer, and the intensity of the electric field is adjusted to adjust the transmittance of light passing through the liquid crystal layer to obtain a desired image. Such liquid crystal displays are typical among portable flat panel displays (FPDs) that are easy to carry. Among them, TFT-LCDs using thin film transistors (TFTs) as switching elements are mainly used.

By the way, a liquid crystal display device employing a vertical alignment (VA) mode, a patterned vertical alignment (PVA) mode, or a mixed vertical alignment (MVA) mode is measured from the front, as shown in FIG. 1, commonly known as a gamma curve. The difference between the normalized luminance and the normalized luminance measured from the side is large, and the difference is not uniform. Due to such a feature, unlike a liquid crystal display device employing an in-plane switching (IPS) mode, a liquid crystal display device employing a VA mode or the like has a disadvantage in that visibility is poor.

On the other hand, the side visibility index is known to be related to the area of the difference in normalized luminance in the front and side, the side visibility index is 0.1 or less in the IPS mode, and the side visibility in the patterned vertical orientation (PVA) The index is 0.31. Lower side visibility indexes mean better visibility from the side.

In order to narrow or uniformize the normalized luminance difference at the front and side, many methods of compensating for the difference in the gamma curve by generating domains having different tilting angles of the liquid crystal with respect to the same voltage applied across the liquid crystal are attempted. It is becoming. This method compensates the gamma curve by shifting the voltage-transmittance curve of the liquid crystal to the right, and the side visibility index is improved to about 0.2, but the luminance decrease is inevitable in white. In particular, as the resolution becomes higher, the luminance decreases. In addition, this method has a limit point of the effect unless the physical properties of the liquid crystal is changed.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a liquid crystal display and a driving method thereof, in which side visibility is improved without reducing luminance in white.

The liquid crystal display according to an embodiment of the present invention for achieving the technical problem,

A liquid crystal panel comprising a plurality of gate lines, a plurality of data lines, and a plurality of pixels connected to the gate lines and the data lines, respectively, and arranged in a matrix form, each pixel including a first subpixel and a second subpixel. Assembly,

A gate driver to turn on / off a thin film transistor included in the pixel by applying a gate on / off voltage to the gate line;

A signal controller which receives an image signal from an external device and generates a gamma signal corresponding to the image signal so that different data voltages are applied to the first subpixel and the second subpixel;

A data driver configured to apply the different data voltages to the first subpixel and the second subpixel according to the gamma signal from the signal controller;

It includes.

The gate line includes a first gate line and a second gate line connected to the first subpixel and the second subpixel, respectively,

 The electronic device may further include a switch unit configured to select one of the first gate line and the second gate line to transfer the gate on / off voltage.

Preferably, the switch unit alternately selects the first gate line and the second gate line in units of frames according to a selection signal from the signal controller.

The gamma signal includes a first gamma signal and a second gamma signal.

The signal controller includes a first lookup table and a second lookup table, and reads the first gamma signal corresponding to the video signal from the first lookup table, and corresponds to the video signal from the second lookup table. Reading the second gamma signal,

The data driver applies a data voltage corresponding to the first gamma signal to the first subpixel, and applies a data voltage corresponding to the second gamma signal to the second subpixel.

The switch unit may be formed on the liquid crystal panel assembly.

The switch unit may be included in the gate driver.

When the gate-on voltage is applied to the first gate line connected to the first subpixel and the second gate line next to the first gate line, the thin film transistor included in the second subpixel may be turned on.

The thin film transistor included in the second subpixel includes a first thin film transistor and a second thin film transistor.

A gate electrode of the first thin film transistor is connected to the first gate line, one of a source electrode and a drain electrode of the first thin film transistor is connected to the second gate line, and the other is the second gate line. It is preferably connected to the gate electrode of the thin film transistor.

The gate on / off voltage may include a first gate on voltage and a second gate on voltage behind the first gate on voltage.

When the second gate on voltage is applied among the gate on / off voltages applied to the first gate line, and the first gate on voltage is applied among the gate on / off voltages applied to the second gate line. The first thin film transistor is turned on.

The data voltage is preferably applied to the data line while the second gate on voltage is applied.

The data voltage includes a first data voltage and a second data voltage, the first data voltage and the second data voltage are applied to the first subpixel, and the second data voltage is applied to the second subpixel. It is preferred to be applied.

The liquid crystal panel assembly may employ any one of a vertical alignment (VA) mode, a patterned vertical alignment (PVA) mode, and a mixed vertical alignment (MVA) mode.

According to another embodiment of the present invention, a plurality of gate lines, a plurality of data lines, and connected to the gate lines and the data lines, respectively, are arranged in a matrix form and include a first subpixel and a second subpixel, respectively. A method of driving a liquid crystal display device comprising a plurality of pixels

Receiving an image signal from an external device,

Generating a gamma signal corresponding to the video signal;

Generating different data voltages according to the gamma signal, and

And applying the different data voltages to the first subpixel and the second subpixel.

The gamma signal includes a first gamma signal and a second gamma signal.

Preferably, the first data voltage corresponding to the first gamma signal and the second data voltage corresponding to the second gamma signal are alternately applied to the first subpixel and the second subpixel in units of frames.

The data voltage includes a first data voltage and a second data voltage, the first data voltage and the second data voltage are applied to the first subpixel, and the second data voltage is applied to the second subpixel. It is preferred to be applied.

DETAILED DESCRIPTION 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.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like parts are designated by like reference numerals throughout the specification. When a part of a layer, film, region, plate, etc. is said to be "on" another part, this includes not only the other part being "right over" but also another part in the middle. On the contrary, when a part is "just above" another part, there is no other part in the middle.

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.

2 is a block diagram of a liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 3 is an equivalent circuit diagram of one pixel of the liquid crystal display according to an exemplary embodiment of the present invention.

As shown in FIG. 2, the liquid crystal display according to the exemplary embodiment of the present invention includes a liquid crystal panel assembly 300, a gate driver 400, a data driver 500, and a data driver The gray voltage generator 800 connected to the signal generator 500 and a signal controller 600 for controlling the gray voltage generator 800 are included.

The liquid crystal panel assembly 300 includes a plurality of display signal lines G ₁ -G _n , D ₁ -D _m and a plurality of pixels connected to the plurality of display signal lines G ₁ -G _n , D ₁ -D _m , and arranged in a substantially matrix form. .

The display signal lines G ₁ -G _n and D ₁ -D _m are a plurality of gate lines G ₁ -G _n for transmitting a gate signal (also called a “scan signal”) and a data signal line or data for transmitting a data signal. Line D ₁ -D _m . The gate lines G ₁ -G _n extend substantially in the row direction and are substantially parallel to each other, and the data lines D ₁ -D _m extend substantially in the column direction and are substantially parallel to each other.

Each pixel includes a switching element Q connected to a display signal line G ₁ -G _n , D ₁ -D _m , and a liquid crystal capacitor C _LC and a storage capacitor C _ST connected thereto. It includes. The holding capacitor C _ST can be omitted as necessary.

The switching element Q is provided on the lower panel 100, and the control terminal and the input terminal are connected to the gate line G ₁ -G _n and the data line D ₁ -D _m, respectively. The output terminal is connected to the liquid crystal capacitor C _LC and the storage capacitor C _ST .

The liquid crystal capacitor C _LC has two terminals, the pixel electrode 190 of the lower panel 100 and the common electrode 270 of the upper panel 200, and the liquid crystal layer 3 between the two electrodes 190 and 270. It functions as a dielectric. The pixel electrode 190 is connected to the switching element Q, and the common electrode 270 is formed on the front surface of the upper panel 200 and receives a common voltage V _com . Unlike in FIG. 3, the common electrode 270 may be provided in the lower panel 100. In this case, both electrodes 190 and 270 may be linear or rod-shaped.

The storage capacitor C _ST is formed by overlapping a separate signal line (not shown) and the pixel electrode 190 provided on the lower panel 100, and a predetermined voltage such as a common voltage V _com is applied to the separate signal line. Is approved. However, the storage capacitor C _ST may be formed such that the pixel electrode 190 overlaps the front end gate line directly above the insulator.

Meanwhile, in order to implement color display, each pixel must display color, which is possible by providing a red, green, or blue color filter 230 in a region corresponding to the pixel electrode 190. In FIG. 3, the color filter 230 is formed in a corresponding region of the upper panel 200. Alternatively, the color filter 230 may be formed above or below the pixel electrode 190 of the lower panel 100.

A polarizer (not shown) for polarizing light is attached to an outer surface of at least one of the two display panels 100 and 200 of the liquid crystal panel assembly 300.

The gray voltage generator 800 generates two sets of gray voltages related to the transmittance of the pixel. One of the two sets has a positive value for the common voltage (V _com ) and the other set has a negative value.

The gate driver 400 is connected to the gate lines G ₁ -G _n of the liquid crystal panel assembly 300 to receive a gate signal formed by a combination of a gate on voltage V _on and a gate off voltage V _off from the outside. It is applied to the gate lines G ₁ -G _n and usually consists of a plurality of integrated circuits.

The data driver 500 is connected to the data lines D ₁ -Dm of the liquid crystal panel assembly 300 to select the gray voltage from the gray voltage generator 800 and apply the gray voltage to the pixel as a data signal. Is made of.

A plurality of gate drive integrated circuits or data drive integrated circuits may be mounted in a tape carrier package (TCP) (not shown) to attach TCP to the liquid crystal panel assembly 300, or to integrate these onto a glass substrate without using TCP. Circuits may be directly attached (chip on glass, COG mounting method), and circuits performing the same functions as those integrated circuits may be directly mounted on the liquid crystal panel assembly 300.

The signal controller 600 generates control signals for controlling operations of the gate driver 400 and the data driver 500, and provides the corresponding control signals to the gate driver 400 and the data driver 500.

Next, the display operation of the liquid crystal display will be described in more detail.

The signal controller 600 inputs an input control signal for controlling the RGB image signals R, G, and B and their display from an external graphic controller (not shown), for example, a vertical sync signal V _sync and a horizontal sync signal. (H _sync ), a main clock (MCLK), a data enable signal (DE) is provided. The signal controller 600 properly processes the image signals R, G, and B according to the operating conditions of the liquid crystal panel assembly 300 based on the input image signals R, G, and B and the input control signal, and controls the gate control signal. After generating the CONT1 and the data control signal CONT2 and the like, the gate control signal CONT1 is sent to the gate driver 400 and the data control signal CONT2 and the processed image signals R ', G', and B 'are processed. ) Is sent to the data driver 500.

The gate control signal CONT1 includes a vertical synchronization start signal STV for indicating the start of output of the gate-on pulse (high period of the gate signal), a gate clock signal CPV for controlling the output timing of the gate-on pulse, and a gate-on pulse. And an output enable signal OE that defines the width of the signal.

The data control signal CONT2 is a load for applying a corresponding data voltage to the horizontal synchronization start signal STH indicating the start of input of the image data R ', G', and B 'and the data lines D ₁ -D _m . Signal LOAD, inverted signal RVS and data that inverts the polarity of the data voltage with respect to common voltage V _com (hereinafter referred to as " polarity of data voltage " by reducing " polarity of data voltage with respect to common voltage "). Clock signal HCLK and the like.

The data driver 500 sequentially receives image data R ′, G ′, and B ′ corresponding to one row of pixels according to the data control signal CONT2 from the signal controller 600, and generates a gray voltage generator ( The image data R ', G', B 'is converted into the corresponding data voltage by selecting the gray voltage corresponding to each of the image data R', G ', and B' among the gray voltages from the 800.

The gate driver 400 applies the gate-on voltage V _on to the gate lines G ₁ -G _n in response to the gate control signal CONT1 from the signal controller 600, thereby applying the gate lines G ₁ -G _n. Turn on the switching element (Q) connected to.

The gate-on voltage V _on is applied to one gate line G ₁ -G _n so that a row of switching elements Q connected thereto is turned on (this period is "1H" or "1 horizontal period). (horizontal period) "and equal to one period of the horizontal sync signal Hsync, the data enable signal DE, and the gate clock CPV], and the data driver 500 converts each data voltage to a corresponding data line D. ₁ -D _m ). The data voltage supplied to the data lines D ₁ -D _m is applied to the corresponding pixel through the turned-on switching element Q.

In this manner, the gate-on voltages V _{on are} sequentially applied to all the gate lines G ₁ -G _n during one frame to apply data voltages to all the pixels. At the end of one frame, the next frame starts and the state of the inversion signal RVS applied to the data driver 500 is controlled so that the polarity of the data voltage applied to each pixel is opposite to that of the previous frame ("frame inversion). "). In this case, the polarity of the data voltage flowing through one data line may be changed (“line inversion”) within one frame or the polarity of the data voltage applied to one pixel row may be different according to the characteristics of the inversion signal RVS ( "Dot reversal").

Next, a liquid crystal display according to another exemplary embodiment of the present invention will be described with reference to FIG. 4. The liquid crystal display divides one pixel into two subpixels and applies different data voltages to each subpixel.

FIG. 4 is an equivalent circuit diagram of two subpixels and a switch unit connected thereto of a liquid crystal display according to another exemplary embodiment of the present invention.

The liquid crystal display device of this embodiment includes the first sub-pixel (P _a) and the connected to the second sub-pixel (P _b) pixels, the first sub-pixel (P _a) consisting of a first switch (S _1), and And a second switch S ₂ connected to the second subpixel P _b .

The first sub-pixel _(a P) comprises data lines (D _j) and a switching element that is connected to the first gate line (G _i1) (Q ₁₎ and a LC capacitor (C _LC1) associated with it. The switching element Q ₁ is a three-terminal element whose control terminal and input terminal are connected to the first gate line G _i1 and data line D _j, respectively, and the output terminal is connected to the liquid crystal capacitor C _LC1 . It is. The liquid crystal capacitor C _LC1 uses the pixel electrode 190a and the common electrode as two terminals.

The second subpixel P _b includes a switching element Q ₂ connected to the data line D _j and the second gate line G _i2 , and a liquid crystal capacitor C _LC2 connected thereto. The switching element Q ₂ is a three-terminal element whose control terminal and input terminal are connected to the second gate line G _i2 and the data line D _j, respectively, and the output terminal is connected to the liquid crystal capacitor C _LC2 . It is. The liquid crystal capacitor C _LC2 has a pixel electrode 190b and a common electrode as two terminals.

One end of the first switch S ₁ is connected to the first gate line G _i1 and turned on / off according to the selection signal SEL from the signal controller 600. Similarly, one end of the second switch S ₂ is connected to the second gate line G _i2 and is turned on / off according to the selection signal SEL from the signal controller 600. The other ends of the first switch S ₁ and the second switch S ₂ are connected to each other and receive a gate signal from the gate driver 400.

The first switch S ₁ and the second switch S ₂ may be embedded in the gate driver IC forming the gate driver 400 or formed on the liquid crystal panel assembly 300. When the first switch S ₁ and the second switch S ₂ are incorporated in the gate driving IC, the gate pad is doubled. Meanwhile, when the first switch S ₁ and the second switch S _{2 are} formed on the liquid crystal panel assembly 300, the first switch S ₁ and the second switch S ₂ may be formed as a circuit using amorphous silicon at a terminal to which the gate signal is input. In this case, the gate pad is not increased, but an additional area for the circuit is required.

Meanwhile, the signal controller 600 driving the liquid crystal display of the present exemplary embodiment includes first and second lookup tables (not shown).

The first lookup table stores a first gamma signal corresponding to a video signal from an external device, and the second lookup table stores a second gamma signal corresponding to a video signal from an external device. The first gamma signal is set to draw the gamma curve shown in FIG. 5A when the corresponding data voltage is applied to the pixel, and the second gamma signal is shown in FIG. 5B when the corresponding data voltage is applied to the pixel. It is set to draw a gamma curve.

5A is a gamma curve for the first subpixel P _a according to another embodiment of the present invention, and FIG. 5B is a gamma curve for the second subpixel P _b according to another embodiment of the present invention. 5C is a gamma curve obtained by adding the gamma curves of FIGS. 5A and 5B.

The signal controller 600 is alternately on a frame-by-frame basis a first switch (S ₁₎ and second switches to generate a selection signal (SEL) for turning on a (S _2), the first switch (S ₁₎ and second switch (S ₂ ) Is applied.

In a frame in which the first switch S ₁ is turned on, the signal controller 600 receives an image signal from an external device and reads a first gamma signal corresponding to the image signal from the first lookup table. The signal controller 600 transmits the first gamma signal to the data driver 500, and the data driver 500 applies a data voltage corresponding to the first gamma signal to the first subpixel.

In a frame in which the second switch S ₂ is turned on, the signal controller 600 receives an image signal from an external device and reads a second gamma signal corresponding to the image signal from the second lookup table. The signal controller 600 transmits the second gamma signal to the data driver 500, and the data driver 500 applies a data voltage corresponding to the second gamma signal to the second subpixel.

When different data voltages are applied to each of the first subpixel and the second subpixel on a frame-by-frame basis, a gamma curve corresponding to the first subpixel and a gamma curve corresponding to the second subpixel are added to the first subpixel and the second subpixel. For the sum of the pixels, a new gamma curve shown in FIG. 5C is generated.

That is, according to the present exemplary embodiment, since the gamma curve can be adjusted differently for the first subpixel region and the second subpixel region, the difference between the gamma curve at the front and the gamma curve at the side is not large as shown in FIG. 5C. The difference is also uniform. Therefore, side visibility can be improved and luminance deterioration at the highest gray level can be eliminated.

Next, a liquid crystal display according to another exemplary embodiment of the present invention will be described with reference to FIG. 6. The liquid crystal display divides one pixel into two subpixels and applies different data voltages to each subpixel.

6 is a diagram illustrating two subpixels and another subpixel adjacent thereto of a liquid crystal display according to another exemplary embodiment of the present invention.

The liquid crystal display of the present exemplary embodiment includes a pixel including the first subpixel P _1a and the second subpixel P _1b .

The first subpixel P _1a includes a switching element Q ₃ connected to the data line D _j and the first gate line G _i , and a liquid crystal capacitor C _LC3 connected thereto. A switching element (Q ₃₎ is a three-terminal device that the control terminal and the input terminal is connected to the first gate line (G _i) and the data lines (D _j), the output terminal is connected to the LC capacitor (C _LC3) It is. The liquid crystal capacitor C _LC3 has the pixel electrode 190c and the common electrode as two terminals.

The second subpixel P _1b includes a first switching element Q ₄ , a second switching element Q ₅ , and a liquid crystal capacitor C _LC4 connected thereto. The first switching element Q ₄ is a three-terminal element whose control terminal and input terminal are connected to the first gate line G _i and the second gate line G _{i + 1,} respectively, and the output terminal is the second terminal element. It is connected to the control terminal of the switching element Q ₅ . The second switching element Q ₅ is also a three-terminal element, the input terminal of which is connected to the data line D _j , and the output terminal of which is connected to the liquid crystal capacitor C _LC4 . The liquid crystal capacitor C _LC4 has a pixel electrode 190d and a common electrode as two terminals.

In the second subpixel P _1b having the structure, when the gate-on voltage is applied to the first gate line G _i and the second gate line G _{i + 1} , the first sub-pixel P _1b may be formed. The switching element Q ₄ and the second switching element Q ₅ are turned on.

The second gate line G _{i + 1} is a gate line of the next stage of the first gate line G _{i, and} is the next stage of the pixel including the first subpixel P _1a and the second subpixel P _1b . The gate line is connected to the first subpixel of the pixel.

Next, the operation of the liquid crystal display of the present embodiment will be described with reference to FIGS. 7A and 7B.

FIG. 7A is a waveform diagram illustrating a gate voltage applied to the first subpixel P _1a and the second subpixel P _1b of FIG. 6 and a data voltage applied to the data line D _j . 6 is a waveform diagram illustrating data voltages applied to the first subpixel P _1a and the second subpixel P _1b , respectively.

As shown in the upper part of FIG. 7A, the data voltage applied to the data line D _j includes the first data voltage V _D1 and the second data voltage V _D2 . The first and second data voltages V _D1 and V _D2 are data voltages corresponding to gamma signals from the signal controller 600. The signal controller 600 receives an image signal from an external device and reads a corresponding gamma signal from a lookup table. This gamma signal does not have a single value but has a double value to generate the first and second data voltages V _D1 , V _D2 .

As shown in the interruption and the bottom of FIG. 7A, the gate voltages applied to the first and second gate lines G _i and G _{i + 1} may include the first gate on voltage V _G1 and the first gate on voltage V. FIG. _And a second gate-on voltage V _G2 behind _G1 ). A first gate line (G _i) a second gate turn-on voltage (V _G2) to be applied to is applied while the data lines a data voltage to the (D _j) applied to the second gate line is applied to the (G _{i + 1)} The first gate on voltage V _G1 is applied while the second gate on voltage V _G2 is applied to the first gate line G _i .

When the second gate on voltage V _G2 is applied to the first gate line G _i , as shown in FIG. 7B, the first data voltage V _D1 and the second data voltage are applied to the first subpixel P _1a . (V _D2 ) is applied. And while the first gate line (G _i) a second gate turn-on voltage (V _G2), and a second gate line of the applied first gate turn-on voltage (V _G1) are overlapped time (G _{i + 1)} applied to the The second data voltage V _D2 is applied to the two subpixels P _1b . As such, different data voltages are applied to the first subpixel P _1a and the second subpixel P _1b .

In the present embodiment, the time when the second gate-on voltage V _G2 starts to be applied to the gate line of the next stage from the time when “1H” starts to be applied to the second gate-on voltage V _{G2 to} one gate line. Defined by.

In the present exemplary embodiment, the first gate-on voltage V _G1 is a signal for turning on the second subpixel at the front end and does not affect the pixel row connected to the corresponding gate line. Although the data voltage applied to the front pixel row is applied to the pixel row while the first gate-on voltage V _G1 is applied, the corresponding data voltage is applied by the subsequent second gate-on voltage V _G2 . This is because the liquid crystal is newly charged by being applied to the pixel row.

By adjusting the gamma signal corresponding to the image signal from the external device to adjust the magnitude of the first data voltage V _D1 and the second data voltage V _D2 , the first subpixel P _1a and the second subpixel ( P _1b ) can create different gamma curves, and the new gamma curve, which is the sum of these two gamma curves, becomes the gamma curve corresponding to the pixel consisting of the first subpixel P _1a and the second subpixel P _1b . . These gamma curves correspond to the same form as the gamma curves shown in FIGS. 5A to 5C. In addition, by adjusting the widths of the waveforms of the first gate-on voltage V _G1 and the second gate-on voltage V _G2 , the ratio of the gamma curve for each subpixel may be adjusted.

Therefore, in the present embodiment, since the gamma curve can be adjusted differently with respect to the first subpixel area and the second subpixel area as in the previous embodiment, side visibility can be improved and luminance deterioration at the highest gray level can be eliminated. .

Unlike the previous embodiment, the present embodiment does not apply different data voltages to two subpixels during two frames, but applies different data voltages to two subpixels by adjusting the width and height of the data signal during one frame. can do. Therefore, there is no existing driving frequency variation in this embodiment. In addition, the gate pad or the data pad may have the same structure as that of the existing liquid crystal panel assembly without changing the structure.

Meanwhile, the liquid crystal panel assembly 300 according to the present invention employs any one of the vertical alignment (VA) mode, the patterned vertical alignment (PVA) mode, and the mixed vertical alignment (MVA) mode.

As such, when one pixel of the liquid crystal display is divided into two subpixels and different data voltages are applied to each subpixel, different gamma curves are drawn for each subpixel, and two pixels for the sum of the two subpixels. A new gamma curve is drawn that combines two different gamma curves. The new gamma curve is small and uniform in difference between the normalized luminance at the front side and the normalized luminance at the side, as shown in FIG. 5C. In addition, there is no decrease in luminance at high gray. Therefore, according to the liquid crystal display of the present invention, not only the side visibility is improved but also the white luminance is not lowered.

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 such, when one pixel of the liquid crystal display is divided into two subpixels and different data voltages are applied to each subpixel, different gamma curves are drawn for each subpixel, and two pixels for the sum of the two subpixels. A new gamma curve is drawn that combines two different gamma curves. Therefore, according to the liquid crystal display of the present invention, not only the side visibility is improved but also the white luminance is not lowered.

1 illustrates a gamma curve of a liquid crystal display.

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

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

FIG. 4 is an equivalent circuit diagram of two subpixels and a switch unit connected thereto of a liquid crystal display according to another exemplary embodiment of the present invention.

5A is a gamma curve for a first subpixel according to another embodiment of the present invention.

5B is a gamma curve for a second subpixel according to another embodiment of the present invention.

5C is a gamma curve obtained by adding the gamma curves of FIGS. 5A and 5B.

6 is a diagram illustrating two subpixels and another subpixel adjacent thereto of a liquid crystal display according to another exemplary embodiment of the present invention.

7A is a waveform diagram illustrating a gate voltage applied to a first subpixel and a second subpixel of FIG. 6 and a data voltage applied to a data line.

FIG. 7B is a waveform diagram illustrating data voltages applied to the first subpixel and the second subpixel of FIG. 6, respectively.

Claims (16)

A liquid crystal panel comprising a plurality of gate lines, a plurality of data lines, and a plurality of pixels connected to the gate lines and the data lines, respectively, and arranged in a matrix form, each pixel including a first subpixel and a second subpixel. Assembly, A gate driver to turn on / off a thin film transistor included in the pixel by applying a gate on / off voltage to the gate line; A signal controller which receives an image signal from an external device and generates a gamma signal corresponding to the image signal so that different data voltages are applied to the first subpixel and the second subpixel; A data driver configured to apply the different data voltages to the first subpixel and the second subpixel according to the gamma signal from the signal controller; Liquid crystal display comprising a. In claim 1, The gate line includes a first gate line and a second gate line connected to the first subpixel and the second subpixel, respectively,  And a switch unit configured to select one of the first gate line and the second gate line to transfer the gate on / off voltage. Liquid crystal display. In claim 2, And the switch unit alternately selects the first gate line and the second gate line in units of frames according to a selection signal from the signal controller. In claim 3, The gamma signal includes a first gamma signal and a second gamma signal. The signal controller includes a first lookup table and a second lookup table, and reads the first gamma signal corresponding to the video signal from the first lookup table, and corresponds to the video signal from the second lookup table. Reading the second gamma signal, The data driver applies a data voltage corresponding to the first gamma signal to the first subpixel, and applies a data voltage corresponding to the second gamma signal to the second subpixel. Liquid crystal display. In claim 4, And the switch unit is formed on the liquid crystal panel assembly. In claim 4, The switch unit is a liquid crystal display device included in the gate driver. In claim 1, The thin film transistor included in the second subpixel is turned on when the gate-on voltage is applied to a first gate line connected to the first subpixel and a second gate line next to the first gate line. In claim 7, The thin film transistor included in the second subpixel includes a first thin film transistor and a second thin film transistor. A gate electrode of the first thin film transistor is connected to the first gate line, one of a source electrode and a drain electrode of the first thin film transistor is connected to the second gate line, and the other is the second gate line. Connected to the gate electrode of the thin film transistor Liquid crystal display. In claim 8, And the gate on / off voltage includes a first gate on voltage and a second gate on voltage behind the first gate on voltage. In claim 9, When the second gate on voltage is applied among the gate on / off voltages applied to the first gate line, and the first gate on voltage is applied among the gate on / off voltages applied to the second gate line. A liquid crystal display device in which the first thin film transistor is turned on. In claim 10, And the data voltage is applied to the data line while the second gate on voltage is applied. In claim 11, The data voltage includes a first data voltage and a second data voltage, the first data voltage and the second data voltage are applied to the first subpixel, and the second data voltage is applied to the second subpixel. Applied liquid crystal display device. In claim 1, The liquid crystal panel assembly adopts any one of a vertical alignment (VA) mode, a patterned vertical alignment (PVA) mode, and a mixed vertical alignment (MVA) mode. A liquid crystal display comprising a plurality of gate lines, a plurality of data lines, and a plurality of pixels connected to the gate lines and the data lines, respectively, and arranged in a matrix and each including a first subpixel and a second subpixel. As a method of driving the device, Receiving an image signal from an external device, Generating a gamma signal corresponding to the video signal; Generating different data voltages according to the gamma signal, and Applying the different data voltages to the first subpixel and the second subpixel. Method of driving a liquid crystal display comprising a. The method of claim 14, The gamma signal includes a first gamma signal and a second gamma signal. A method of driving a liquid crystal display device which alternately applies a first data voltage corresponding to the first gamma signal and a second data voltage corresponding to the second gamma signal to the first subpixel and the second subpixel in a frame unit. . The method of claim 15, The data voltage includes a first data voltage and a second data voltage, the first data voltage and the second data voltage are applied to the first subpixel, and the second data voltage is applied to the second subpixel. A driving method of an applied liquid crystal display device.