WO2016010376A1

WO2016010376A1 - Liquid crystal panel, liquid crystal display device, and method for driving same

Info

Publication number: WO2016010376A1
Application number: PCT/KR2015/007380
Authority: WO
Inventors: 박순규
Original assignee: 엘지디스플레이 주식회사
Priority date: 2014-07-15
Filing date: 2015-07-15
Publication date: 2016-01-21

Abstract

The present invention relates to a liquid crystal panel, a liquid crystal display device, and a method for driving the same, which can improve a display quality by changing common voltage and gamma voltage according to a driving time interval. The liquid crystal display device of the present invention includes a timing controller, a voltage generation unit, a data driver, and a liquid panel. The timing controller may generate a voltage control signal for switching an initial state to a stable state using a predetermined switching time point. The voltage generation unit may receive the voltage control signal, supply first gamma voltage and first common voltage during the initial state, and supply second gamma voltage and second common voltage during the stable state. The data driver may receive the first gamma voltage during the initial state and receive the second gamma voltage during the stable state. Further, the liquid crystal panel may suppress a short-term afterimage when the first gamma voltage and the first common voltage are applied, and suppress a long-term afterimage when the second gamma voltage and the second common voltage are applied.

Description

Liquid crystal panel, liquid crystal display device and driving method thereof

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal panel, a liquid crystal display device, and a driving method thereof, which can improve display quality by adjusting a common voltage and a gamma voltage according to a driving time.

Liquid crystal display devices (LCDs) are suitable for portable devices because of the advantages of mass production technology, ease of driving means, low power consumption, high definition, and large screen, and the field of application is continuously expanding.

Liquid crystal display devices have been developed in various ways, such as twisted nematic (TN) mode, vertical alignment (VA) mode, in plane switching (IPS) mode, and fringe field switching (FFS) mode.

In the IPS mode, the pixel electrode and the common electrode are alternately arranged horizontally to generate a horizontal electric field between both electrodes to adjust the arrangement of the liquid crystal layer. In the FFS mode, the pixel electrode and the common electrode spaced apart from each other at regular intervals are arranged with an insulating layer interposed therebetween, thereby forming an fringe field between the pixel electrode and the common electrode to adjust the arrangement of the liquid crystal layer. .

The liquid crystal display of the IPS mode performs gamma tuning to improve afterimages. The common voltage and the center voltage before gamma tuning will be described with reference to FIG. 1A.

1A is a diagram illustrating a common voltage Vcom and a center voltage Vcenter before gamma tuning.

Referring to FIG. 1A, prior to gamma tuning, a conventional liquid crystal display device uses a common voltage and a gamma voltage. Gamma data of a conventional liquid crystal display device includes a positive gamma curve and a negative gamma curve that are symmetrical with respect to a common voltage. The gamma voltage is generated using gamma data. The common voltage has the same voltage level as the center voltage of the positive gamma curve and the negative gamma curve. Therefore, the center of the gamma voltage is equal to the center voltage Vcenter. The "center voltage" can be considered as the center voltage of the positive gamma curve and negative gamma curve for each gray level (e.g., 8 bits, G0-G255 for 255-gray).

In other words, the positive gamma curve and the negative gamma curve may be symmetrical for each gray level based on the same center voltage Vcenter as the common voltage. Therefore, the common voltage of the conventional liquid crystal display device is the same as the center voltage Vcenter and has a constant voltage level according to the gray level.

Furthermore, the positive gamma curve and the negative gamma curve are alternately supplied to the pixel array for polarity inversion of the pixel array in each frame to prevent damage to the liquid crystal layer of the conventional liquid crystal panel. Theoretically, the positive gamma curve and the negative gamma curve can minimize flicker and afterimage when they are symmetric with respect to a common voltage. For example, at gray level G0 the positive gamma curve is 4.5V and the negative gamma curve is 3.5V. Therefore, the positive gamma curve has a potential difference of 0.5V based on the common voltage. The negative gamma curve has a potential difference of 0.5V based on the common voltage. Therefore, the potential difference between the positive gamma curve and the negative gamma curve is the same.

However, in a real driving environment, when the common voltage is the same as the center voltage, flicker and afterimage occur due to various causes such as electrical resistance, parasitic capacitance, and thermal stress of the liquid crystal panel.

Before gamma tuning, due to the various causes described above, an optimal common voltage (Optimal Vcom) for each gray level of a conventional liquid crystal display device is unevenly displayed. That is, to minimize flicker and afterimage problems, different optimal voltages are required for each gray level. However, the conventional liquid crystal display device can use only one common voltage because the common electrode is commonly connected to the pixel array. Therefore, even if the non-uniform optimal common voltage (Optimal Vcom) for each gray level is evaluated, the display quality is deteriorated because the non-uniform optimal common voltage cannot be supplied to the conventional liquid crystal display device.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and a liquid crystal display device capable of eliminating or improving the afterimage problem in both the initial state and the stable state by selectively supplying the optimum common voltage and the optimum gamma voltage according to the driving time. It is a technical problem to provide a driving method thereof.

The present invention is to solve the above-described problems, to provide a liquid crystal display device and a driving method thereof that can reduce the manufacturing cost and increase the manufacturing efficiency by selectively supplying the optimum common voltage and the optimum gamma voltage according to the driving time Let it be technical problem.

In addition to the technical task of the present invention mentioned above, other features and advantages of the present invention will be described below, or from such description and description will be clearly understood by those skilled in the art.

The liquid crystal panel according to the embodiment of the present invention for achieving the above-described technical problem, can suppress the flicker degree and short-term afterimage when the first gamma voltage and the first common voltage are received, the second gamma voltage and the second And a pixel array capable of suppressing flicker degree and long-term afterimage when a common voltage is received, wherein the first gamma voltage is received in an initial state and the second gamma voltage is received in a stable state, wherein the initial state is predetermined. And a first gamma voltage is generated using first gamma data including a first positive gamma curve and a first negative gamma curve based on a first center voltage. The first positive gamma curve and the first negative gamma curve are symmetric with respect to the first center voltage and correspond to all gray levels. The center voltage is non-uniform, and the second gamma voltage is generated using second gamma data including a second positive gamma curve and a second negative gamma curve based on a second center voltage, wherein the second positive gamma curve and The second negative gamma curve is symmetrical with respect to the second center voltage, and the second center voltage corresponding to all gray levels is nonuniform.

In the liquid crystal panel according to an exemplary embodiment of the present disclosure, the first common voltage is determined based on first deviation data, the second common voltage is determined based on second deviation data, and the first and second deviation data. Are greater than the deviation at the relatively high gray level.

In the liquid crystal panel according to the exemplary embodiment of the present invention, the first common voltage is higher than the second common voltage.

In the liquid crystal panel according to the exemplary embodiment of the present invention, the first gamma voltage is higher than the second gamma voltage, and the voltage difference between the first gamma voltage and the second gamma voltage is substantially the same in the pixel array.

In the liquid crystal panel according to the exemplary embodiment of the present invention, the voltage at the relatively low gray level of the first center voltage is greater than the voltage at the relatively high gray level of the first center voltage.

In the liquid crystal panel according to the exemplary embodiment of the present invention, the maximum deviation value of the first and second deviation data is less than 0V or 100mV.

In the liquid crystal panel according to the embodiment of the present invention, the duration of the initial state is based on the aging state of the liquid crystal panel, the predetermined switching time point is determined according to the initial state duration, and the first By adjusting the gamma voltage, the first common voltage, the second gamma voltage and the second common voltage, the flicker degree, the short-term afterimage and the long-term afterimage in the initial state and the stable state are substantially the same.

According to an exemplary embodiment of the present invention, a liquid crystal display device includes a timing controller, a voltage generator, a data driver, and a liquid crystal panel. The timing controller may generate a voltage control signal for switching from an initial state to a stable state using a predetermined switching time point. The voltage generator may receive the voltage control signal, may supply a first gamma voltage and a first common voltage during the initial state, and may supply a second gamma voltage and a second common voltage during the stable state. The data driver may receive the first gamma voltage during the initial state, and receive the second gamma voltage during the stable state. The liquid crystal panel may suppress short-term afterimages when the first gamma voltage and the first common voltage are applied, and suppress long-term afterimages when the second gamma voltage and the second common voltage are applied.

In the liquid crystal display according to the exemplary embodiment of the present disclosure, the voltage generator includes a first bank capable of storing first gamma data and first common voltage data, and a second capable of storing second gamma data and second common voltage data. At least a bank, wherein the first gamma voltage is generated based on the first gamma data, the second gamma voltage is generated based on the second gamma data, and the first common voltage is the first common voltage. The second common voltage is generated based on data, and the second common voltage is generated based on the second common voltage data.

The liquid crystal display device according to the embodiment of the present invention further includes a third bank, and the timing controller is configured to switch the initial state to an intermediate state by using a predetermined first switching time point and then set a predetermined second switching time point. The voltage control unit may be configured to generate the voltage control signal for switching the intermediate state to the stable state, and the voltage generator may supply a third gamma voltage and a third common voltage during the intermediate state. May store third gamma data and the third common voltage data, wherein the third gamma voltage may be generated based on the third gamma data, and the third common voltage is based on the third common voltage data. Can be generated.

In the liquid crystal display according to the exemplary embodiment of the present invention, the first common voltage is the same at all gray levels, and the first gamma data includes a first positive gamma curve and a first negative gamma curve, and the first positive A gamma curve and the first negative gamma curve are asymmetrical with respect to the first common voltage.

In the liquid crystal display according to the exemplary embodiment of the present invention, the second common voltage is the same at all gray levels, and the second gamma data includes a second positive gamma curve and a second negative gamma curve, and the second positive A gamma curve and the second negative gamma curve are asymmetrical with respect to the second common voltage.

In the liquid crystal display according to the exemplary embodiment of the present invention, the first common voltage and the second common voltage are different, and the first gamma data and the second gamma data are different.

In the liquid crystal display according to the exemplary embodiment of the present invention, the switching time point is determined in relation to an operation time of the liquid crystal panel.

In accordance with an aspect of the present invention, there is provided a method of driving a liquid crystal display device, the timing controller generating a voltage control signal for switching from an initial state to a stable state using a predetermined switching time point. ; Receiving, by the voltage generator, the voltage control signal and supplying a first gamma voltage and a first common voltage during the initial state and a second gamma voltage and a second common voltage during the stable state; Receiving, by a data driver, the first gamma voltage during the initial state and the second gamma voltage during the stable state; And a liquid crystal panel including a pixel array suppressing short-term afterimage when the first gamma voltage and the first common voltage are applied, and suppressing long-term afterimage when the second gamma voltage and the second common voltage are applied. It includes.

The liquid crystal display and the driving method thereof according to the present invention can remove or improve the afterimage of the initial state by adjusting the common voltage and the gamma voltage according to the driving time.

The liquid crystal display and the driving method thereof according to the present invention can remove or improve the afterimage in a stable state by adjusting the common voltage and the gamma voltage according to the driving time.

Since the liquid crystal display device and the driving method thereof according to the present invention can shorten the final inspection time including afterimage inspection by adjusting the common voltage and the gamma voltage according to the driving time, the manufacturing cost, manufacturing time reduction and afterimage can be improved. Manufacturing efficiency can be improved.

In addition, other features and advantages of the present invention may be newly understood through the embodiments of the present invention.

FIG. 1A is a diagram illustrating an optimum common voltage Vcom and a center voltage Vcenter before gamma tuning.

FIG. 1B is a diagram illustrating an optimum common voltage Vcom and a center voltage Vcenter after gamma tuning.

FIG. 2A is a diagram illustrating that the optimum common voltage changes as the driving time of the liquid crystal display including the liquid crystal panel elapses. FIG.

FIG. 2B is a diagram illustrating a problem caused by using the common voltage Vcom and the gamma data as fixed values in the initial state and the stable state.

FIG. 2B shows the liquid crystal according to the example of the present invention when adjusting the optimum common voltage and the optimum gamma voltage by the adjusted Vop data supplied for both the initial state (short run) and the stable state (long run). It is a figure for demonstrating the characteristic of a display apparatus.

3A is a diagram schematically illustrating a liquid crystal display device according to an exemplary embodiment of the present invention.

3B is a diagram schematically illustrating a liquid crystal display device according to another exemplary embodiment of the present invention.

4 is a diagram illustrating a timing controller and a voltage generator according to an exemplary embodiment of the present invention.

5 is a diagram illustrating a method of changing a gamma voltage and a common voltage according to an initial state and a stable state.

6 to 8 are views illustrating a method of driving a liquid crystal display device according to an exemplary embodiment of the present invention.

FIG. 9 is a diagram illustrating improved display quality when selectively supplying a common voltage and a gamma voltage optimized for an initial state and a stable state according to a driving time.

10 is a diagram illustrating a timing controller and a voltage generator according to another embodiment of the present invention.

11 is a diagram illustrating a timing controller and a voltage generator according to another embodiment of the present invention.

12 is a diagram illustrating a timing controller and a voltage generator and a driving method thereof according to another embodiment of the present invention.

Hereinafter, a liquid crystal display and a driving method thereof according to the present invention will be described in detail with reference to the accompanying drawings. Like numbers refer to like elements throughout. In the following description, detailed descriptions of configurations and functions known in the art and not related to the core configuration of the present invention may be omitted.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various forms, and only the embodiments are intended to complete the disclosure of the present invention and to provide general knowledge in the technical field to which the present invention pertains. It is provided to fully convey the scope of the invention to those skilled in the art, and the present invention is defined only by the scope of the claims.

Shapes, sizes, ratios, angles, numbers, and the like disclosed in the drawings for describing the embodiments of the present invention are exemplary, and the present invention is not limited to the illustrated items. Like reference numerals refer to like elements throughout. In addition, in describing the present invention, if it is determined that the detailed description of the related known technology may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. In the case where 'comprises', 'haves', 'consists of' and the like mentioned in the present specification are used, other parts may be added unless 'only' is used. In the case where the component is expressed in the singular, the plural includes the plural unless specifically stated otherwise.

In interpreting a component, it is interpreted to include an error range even if there is no separate description. The features of each of the various embodiments of the invention may be combined or combined with one another, in whole or in part, and various interlocking and driving technically may be possible, and each of the embodiments may be independently implemented with respect to each other or may be implemented in association with each other. It may be.

FIG. 1B is a diagram for explaining an optimal common voltage and a center voltage after gamma tuning.

Referring to FIG. 1B, after gamma tuning, the liquid crystal panel of the IPS mode or the FFS mode according to the example of the present invention is a nonlinear (non-uniform) gamma tuning (hereinafter referred to as "gamma tuning") to reduce the degree of afterimage and flicker. Do this. The gamma tuning analyzes or detects a difference between an optimum common voltage Optigcom for each gray level G0 to G255 and a center voltage Vcenter for each gray level. The optimal common voltage (Optimal Vcom) is a common voltage required to reduce the degree of flicker and residual image for each gray level.

By gamma tuning, the center voltage Vcenter for each gray level is adjusted to an optimal common voltage Vcom that is uniform for each gray level. As a result, the center voltage Vcenter for each gray level becomes nonuniform. In other words, by adjusting the uniform center voltage Vcenter to the nonuniform center voltage Vcenter, a common voltage optimized for all gray levels (for example, G0 to G255) can be obtained.

Gamma data includes positive gamma curves and negative gamma curves. Positive gamma curves and negative gamma curves are adjusted based on uneven center voltage (Vcenter). Positive gamma curves and negative gamma curves are symmetrical with respect to an uneven center voltage (Vcenter). Here, the symmetry may be interpreted as having the same potential difference with respect to the nonuniform center voltage Vcenter.

Meanwhile, the positive gamma curve and the negative gamma curve are determined in consideration of the optimum common voltage for each gray level. The positive and negative gamma curves are asymmetric based on the regulated common voltage (the optimal common voltage that can be applied to all gray levels).

In addition, due to various causes such as deterioration stress of the liquid crystal panel, electrical resistance, and parasitic capacitance, the regulated common voltage may have a voltage level lower than that of the uneven center voltage Vcenter.

In order to adjust the center voltage Vcenter, adjusted gamma data is generated. The term "regulated gamma data" means that the optimal common voltage (Optimal Vcom) is uniform across all gray levels (e.g. G0-G255), and is based on the nonuniform center voltage (Vcenter) of each gray level. And negative gamma curve can be regarded as adjusted gamma voltage value data. Therefore, the nonuniform center voltage Vcenter for each gray level serves as an adjustment criterion for the adjusted gamma data Vop data for all gray levels in order to uniformize the optimum common voltage Vcom for all gray levels. In other words, the positive gamma curve and negative gamma curve of the adjusted Gap data are adjusted based on the adjusted nonuniform center voltage Vcenter. As a result, the optimum gamma voltage is generated by the adjusted Gap data comprising the adjusted positive gamma curve and the adjusted negative gamma curve.

If the optimum common voltage (Optimal Vcom) is uniform for every gray level (e.g., G0 to G255), flicker can be minimized for all gray levels, and further, the degree of persistence can be reduced for all gray levels. have. Therefore, the regulated common voltage should be set to be substantially equal to or closest to the optimum common voltage.

In addition, the characteristics of the liquid crystal panel may be changed under aging conditions. For example, the aging condition may be a condition in which the backlight is driven at room temperature (eg, 20 ° C. to 30 ° C.) and an arbitrary test pattern is supplied to the liquid crystal panel to display an image. For example, when a liquid crystal display device including a liquid crystal panel is driven, electrical and / or physical properties of the liquid crystal display device may be changed based on the driving time. More specifically, the electrical stress or thermal stress of the liquid crystal display device may be changed. Therefore, the optimum common voltage for every gray level (for example, G0 to G255) is changed based on the driving time. That is, since the degree of flicker and the degree of residual image change based on the driving time, the display quality of the liquid crystal display device may change depending on the operation time if the common voltage and the gamma voltage are fixed regardless of the aging conditions of the liquid crystal panel.

FIG. 2A illustrates a change in an optimum common voltage according to a driving time of a liquid crystal display including a liquid crystal panel.

Referring to FIG. 2A, the optimum common voltage when the liquid crystal panel is in an initial state and the optimum common voltage when it is in a stable state are different from each other. Specifically, the common voltage in the stable state is smaller than the optimum common voltage in the initial state. As such, since the optimum common voltage changes according to the driving time of the liquid crystal panel, a gamma voltage and a common voltage optimized for the initial state are needed to reflect the change of the optimum common voltage, and a gamma voltage and the common optimized for the stable state are required. Voltage is required.

FIG. 2B shows the liquid crystal according to the example of the present invention when adjusting the optimum common voltage and the optimum gamma voltage by the adjusted Vop data supplied for both the initial state (short run) and the stable state (long run). It is a figure for demonstrating the characteristic of the liquid crystal display device containing a panel.

Referring to FIG. 2B, the initial state lasts for the next predetermined time period started after the liquid crystal display device according to the example of the present invention is turned on. The steady state begins after the end of the initial state. As described above, the aging condition is changed by the driving time, and thus the optimum common voltage and the optimum gamma voltage are changed based on the driving time.

The steady state starts after a certain time. For example, the steady state begins approximately 30 minutes after the initial state (eg, 30 minutes after turn-on of the liquid crystal display device). Thus, the initial state period may be approximately 30 minutes. However, the predetermined time of the initial state may be changed according to various kinds of the liquid crystal display device including the liquid crystal panel, and is not limited to the present invention.

For example, the optimum common voltage and the optimum gamma voltage for both the initial state and the stable state may be set based on the stable state. In this case, the optimum common voltage and the optimum gamma voltage are not suitable for the initial state. That is, the optimum common voltage and the optimum gamma voltage optimized for the stable state are suitable for minimizing the degree of long-term afterimage. Therefore, there is a problem that the degree of short-term afterimage increases during the initial state.

For example, the optimum common voltage and the optimum gamma voltage for both the initial state and the stable state may be set based on the initial state. In this case, the optimum common voltage and the optimum gamma voltage are not suitable for the stable state. That is, the optimum common voltage and the optimum gamma voltage optimized for the initial state are suitable for minimizing the degree of short-term afterimage. However, the degree of long-term afterimage has a problem of increasing during the steady state.

Therefore, the optimum common voltage and the optimum gamma voltage for the initial state and the stable state are different due to the difference in the aging conditions of the liquid crystal display device including the liquid crystal panel. Therefore, there is a difficulty in suppressing both short-term and long-term afterimages with an optimal common voltage and an optimum gamma voltage that are not variable. In addition, since the optimum common voltage and the optimum gamma voltage for the initial state and the stable state are different, when only the optimal common voltage is adjusted in the initial state and the stable state, it is difficult to suppress both short-term and long-term afterimages. In addition, since the optimum common voltage and the optimum gamma voltage for the initial state and the stable state are different, when only the optimum gamma voltage is adjusted in the initial state and the stable state, it is difficult to suppress both short-term and long-term afterimages.

3A is a diagram schematically illustrating a liquid crystal display device including a liquid crystal panel according to an exemplary embodiment of the present invention.

Referring to FIG. 3A, a liquid crystal display device 100 according to an exemplary embodiment of the present invention may include a liquid crystal panel 110, a timing controller 120, a voltage generator 130, a data driver 150, and a gate driver 140. The backlight unit may include a backlight unit for supplying light to the liquid crystal panel 110, a backlight driver for driving a light source, and a power supply unit.

The liquid crystal panel 110 displays an image according to an input image signal data, and includes a plurality of gate lines GL and a plurality of data lines DL. In addition, the liquid crystal panel 110 includes a plurality of pixels formed for each region defined by the gate lines GL and the data lines DL. Alternatively, the plurality of pixels may also be configured by sharing the gate lines GL or the data lines DL. Each pixel is provided with a pixel electrode and a common electrode. Each pixel is formed with a thin film transistor (TFT) as a switching element.

The timing controller 120 aligns the image signals from the outside, converts them into digital image data R, G, and B in units of frames, and supplies the aligned digital image data to the data driver 150.

In addition, the timing controller 120 uses the vertical synchronizing signal Vsync, the horizontal synchronizing signal Hsync, and the clock signal CLK to receive a gate control signal GCS for controlling the gate driver 140. A data control signal DCS for controlling the data driver 150 is generated. The gate control signal GCS is supplied to the gate driver 140, and the data control signal DCS is supplied to the data driver 150.

The data control signal DCS may include a source start pulse (SSP), a source sampling clock (SSC), a source output enable (SOE), and a polarity control (POL). It may include a signal. The gate control signal GCS may include a gate start pulse (GSP), a gate shift clock (GSC), and a gate output enable (GOE).

In addition, the timing controller 120 generates a voltage control signal (VCS) for changing the common voltage and the gamma voltage based on the driving time of the liquid crystal display device, and generates the voltage control signal VCS. Supply to the generation unit 130. Hereinafter, the common voltage and the gamma voltage are assumed to be the optimum common voltage and the optimum gamma voltage according to gamma tuning.

The voltage generator 130 may include, for example, a programmable gamma IC (P-gamma IC), and may be a power supply IC, a DC-DC converter, a buck converter, and / or an integrated power IC. The voltage generator 130 may include a look-up table in which gamma data (a gamma voltage having positive and negative gamma curve characteristics) and a digital-to-analog converter (DAC) converting gamma data into gamma voltages. Include.

In addition, the voltage generator 130 generates the first gamma voltage GMA1 as a gamma voltage adjusted to be optimized to an initial state based on the driving time. The second gamma voltage GMA2 is generated as the gamma voltage adjusted to be optimized for the stable state. The voltage generator 130 supplies the first gamma voltage GMA1 and the second gamma voltage GMA2 to the data driver 150.

The voltage generator 130 generates the first common voltage Vcom1 optimized for the initial state based on the driving time. In addition, the second common voltage Vcom2 optimized to the stable state is generated. That is, the first common voltage Vcom1 is a regulated common voltage optimized for an initial state, and the second common voltage Vcom2 is a regulated common voltage optimized for a stable state. The voltage generator 130 supplies the first common voltage Vcom1 and the second common voltage Vcom2 to the data driver 150.

The liquid crystal panel 110 may receive a first common voltage Vcom1 during the initial state, and may receive a second common voltage Vcom2 during the stable state.

The first common voltage Vcom1 is a regulated common voltage optimized for an initial state, and the second common voltage Vcom2 is an adjusted common voltage optimized for a stable state. Here, the adjusted common voltage is characterized in that the voltage level of the first common voltage Vcom1 is higher than the voltage level of the second common voltage Vcom2. The third gamma voltage GMA3 and the third common voltage Vcom3 illustrated in FIG. 3A will be described with reference to FIG. 12. In addition, although at least three gamma voltages and three common voltages are illustrated in FIG. 3A, only two gamma voltages and two common voltages may be used.

Referring to FIG. 3B, the voltage generator 130 generates the first gamma voltage GMA1 as a gamma voltage adjusted to be optimized for the initial state based on the driving time. The second gamma voltage GMA2 is generated as the gamma voltage adjusted to be optimized for the stable state. The voltage generator 130 selectively supplies the first gamma voltage GMA1 and the second gamma voltage GMA2 to the data driver 150 based on the driving time.

The voltage generator 130 generates the first common voltage Vcom1 optimized for the initial state based on the driving time. In addition, the second common voltage Vcom2 optimized to the stable state is generated. The voltage generator 130 selectively supplies the first common voltage Vcom1 and the second common voltage Vcom2 to the liquid crystal panel 110 based on the driving time.

The first common voltage Vcom1 is a regulated common voltage optimized for an initial state, and the second common voltage Vcom2 is an adjusted common voltage optimized for a stable state. Here, the adjusted common voltage is characterized in that the voltage level of the first common voltage Vcom1 is higher than the voltage level of the second common voltage Vcom2.

The third gamma voltage GMA3 and the third common voltage Vcom3 illustrated in FIG. 3B will be described with reference to FIG. 12.

When an image is displayed on the liquid crystal panel 110, gamma tuning is performed to improve afterimages. In this case, the difference between the optimal common voltage Vcom for minimizing flicker for each gray and the optimal common voltage Vcom of the reference gray may be compensated for the center voltage Vcenter for each gray.

Here, the optimum common voltage for each gray means a common voltage at which flicker occurs the least when the common voltage is changed to a gray star (0 to 255 gray). In addition, the center voltage Vcenter means a center value between the positive gamma and the negative gamma for each gray. That is, the positive gamma and the negative gamma are symmetrical with respect to the center voltage.

The first gamma voltage GMA1 is generated based on the first gamma data Vop1 data, and the first gamma data Vop1 data includes deviations of optimal common voltages set for each gray such that afterimages are suppressed or minimized in an initial state. The maximum value of is reflected. The second gamma voltage is generated based on the second gamma data (Vop2 data), and the second gamma data (Vop2 data) includes the deviation of the optimum common voltages set for each gray such that afterimages are suppressed or minimized in a stable state. The maximum value is reflected.

Here, it is most preferable that the deviation of the optimum common voltages set for each gray is 0V. In the present invention, the deviation of the optimum common voltages set for each gray is set in the range of 0V to 100mV.

The timing controller 120 for generating the first common voltage Vcom1 and the first gamma voltage GMA1 optimized for the initial state and the second common voltage Vcom2 and the second gamma voltage GMA2 optimized for the stable state. The configuration and driving method of the voltage generator 130 will be described in detail with reference to FIGS. 4 to 8.

Subsequently, the gate driver 140 generates a scan signal (gate driving signal) for sequentially driving the TFTs formed in each pixel based on the gate control signal GCS supplied from the timing controller 120. The generated scan signal is sequentially supplied to each of the gate lines GL of the liquid crystal panel 110, and a plurality of TFTs are driven by the scan signal.

The data driver 150 supplies the digital image data R, G, and B supplied from the timing controller 120 using the first gamma voltage GMA1 or the second gamma voltage GMA2 supplied from the voltage generator 130. ) Is converted into an analog data voltage (data signal). The data driver 150 supplies a data voltage to each of the data lines DL of the liquid crystal panel 110 based on the data control signal DCS from the timing controller 120. In addition, the data driver 150 supplies the first common voltage Vcom1 or the second common voltage Vcom2 to the common electrode. However, the present invention is not limited thereto, and the voltage generator 130 may directly supply the first common voltage Vcom1 or the second common voltage Vcom2 to the common electrode.

The backlight unit is for irradiating light to the liquid crystal panel 110, and includes a plurality of light sources for generating light and a plurality of optical members (diffusion sheet, polarizing sheet, light guide plate, or the like) for improving the efficiency of light generated by the plurality of light sources. Diffuser plate). The plurality of light sources may be a cold cathode fluorescent lamp (CCFL), an external electrofluorescent lamp (EEFL), or a light emitting diode (LED).

Referring to FIG. 4, the liquid crystal display 100 according to the exemplary embodiment simultaneously switches the common voltage and the gamma voltage based on a driving time determined according to an aging condition. Therefore, the liquid crystal display device 100 may suppress or minimize afterimages and flicker in both an initial state and a stable state.

The timing controller 120 includes a counter 122 and a common voltage shifter 124. In addition, the voltage generator 130 may be configured for the first bank 132 and the stable state for storing the first common voltage data Vcom1 data and the first gamma data Vop1 data for the initial state (optimized for the initial state). And a second bank 134 for storing the second common voltage data Vcom2 data (optimized for the stable state) and the second gamma data Vop2 data.

The first common voltage data Vcom1 data and the first gamma data Vop1 data optimized for the initial state are generated in the manufacturing process of the liquid crystal display including the liquid crystal panel and are stored in the first bank 132. In addition, the second common voltage data Vcom2 data and the second gamma data Vop2 data optimized for the stable state are generated in the manufacturing process of the liquid crystal display including the liquid crystal panel and stored in the second bank 134. . Each gamma data includes first gamma data including a first positive gamma curve and a first negative gamma curve, and second gamma data including a second positive gamma curve and a second negative gamma curve. It is characterized by that.

The first bank 132 and the second bank 134 are embedded in the voltage generator 130, and thus, the quick switching of the first gamma data Vop data and the second gamma data Vop data may be performed. It is possible. In particular, since switching of the first gamma data and the second gamma data should be performed within one frame period (for example, 16.7 ms), the plurality of bank structures may be effective for rapid switching. have. If the switching is not performed within one frame period, the display quality may be degraded during the switching.

First gamma tuning is performed. For example, the first deviation data ΔVop1 data is determined based on the first common voltage data Vcom1 data determined by the first gamma data Vop1 data. In order to determine the first deviation data ΔVop1 data, the non-uniform optimal common voltage for each gray level corresponding to the uniform center voltage Vcenter of the aging condition of the initial state is in the state before the gamma tuning shown in FIG. 1A. Is evaluated. As described above, since the liquid crystal display device is configured to supply a common voltage to a common electrode connected to all pixels, an uneven optimal common voltage may be practically impossible. The first deviation data ΔVop1 data is characterized in that a deviation degree at a low gray level is greater than a deviation degree at a high gray level. In this case, the first deviation data ΔVop1 data sets the highest gray level as the reference gray level. However, the reference gray level of the present invention is not limited thereto.

Uniform and optimized first common voltage data Vcom1 data for all gray levels (for example, G0 to G255) is determined by the first deviation data ΔVop1 data. For example, the first deviation data [Delta] Vop1 data for all gray levels can be calculated by calculating the deviation of the non-uniform optimal common voltage required for all gray levels. In this case, the maximum non-uniform optimal common voltage is used as the reference voltage. The remainder of the non-uniform optimal common voltage is adjusted to be equal to the reference voltage. Thus, the adjusted value is calculated to generate the first deviation data [Delta] Vop1 data for each gray level, and the adjusted common voltage is made uniform. As a result, the first common voltage data Vcom1 data is determined. However, the present invention is not limited to the value of the reference voltage.

The first gamma data Vop1 data is determined based on the first deviation data ΔVop1 data and the first center voltage Vcenter1. For example, the uniform center voltage is adjusted by the first deviation data ΔVop1 data, and thus the first center voltage Vcenter1 is determined. The first center voltage Vcenter1 is characterized in that the center voltage at the low gray level is greater than the center voltage at the high gray level based on the first deviation data ΔVop1 data. In other words, the first center voltage Vcenter1 corresponds to the first deviation data ΔVop1 data.

The first positive gamma curve and the first negative gamma curve of the first gamma data Vop data are adjusted based on the first center voltage Vcenter1.

For example, at a certain gray level, the first center voltage is increased to 100 mV, whereby at a given gray level both the first positive gamma curve and the first negative gamma curve of the first gamma data (Vop1 data) are up to 100 mV. Increases. The first gamma data Vop1 data includes a first positive gamma curve and a first negative gamma curve symmetrical with respect to the first center voltage Vcenter1, and the first positive gamma curve and the first negative gamma curve are first common voltage data. It is characterized by asymmetry with respect to (Vcom1). Here, since the first center voltage Vcenter1 is nonuniform for each gray level, and the first common voltage data Vcom1 data is uniform for each gray level, flicker and short-term afterimages may be reduced in an initial state.

The maximum deviation value of the first deviation data ΔVop1 data may be equal to or less than 100 mV. As described above, although the maximum deviation value has been described as being 0V, in the actual driving environment, the maximum deviation value can be adjusted to 0V or more. Accordingly, at least the maximum deviation value of the first deviation data ΔVop1 data is less than 100 mV. In this case, flicker and short-term afterimage may be sufficiently reduced.

Here, the first positive gamma curve and the first negative gamma curve are symmetrical based on the first center voltage Vcenter1. Since the first center voltage Vcenter1 is a center value of the first positive gamma curve and the first negative gamma curve, when the first positive gamma curve and the first negative gamma curve are present, the first center voltage Vcenter1 may be calculated. The center voltage does not necessarily need to be stored as specific data. If there is a positive gamma curve and a negative gamma curve, the center voltage can be calculated and used as necessary. However, the present invention is not limited thereto, and data of the first center voltage Vcenter1 may be stored in a memory, and then loaded and used as necessary.

Subsequently, a second gamma tuning is performed. The second gamma tuning will be briefly described, and redundant description of the first gamma tuning will be omitted. For example, the second deviation data ΔVop2 data is determined based on the second common voltage determined by the second gamma data Vop2 data. In order to determine the second deviation data ΔVop2 data, the non-uniform optimal common voltage for each gray level related to the uniform center voltage Vcenter by the steady state aging condition is determined in the state before the gamma tuning shown in FIG. 1A. Is evaluated. The second deviation data ΔVop2 data is characterized in that the degree of deviation in the low gray level is greater than the degree of deviation in the high gray level based on the desired non-uniform optimal common voltage.

The uniform and optimized second common voltage for all gray levels (eg, G0 to G255) is determined by the second deviation data ΔVop2 data.

The second center voltage Vcenter2 is characterized in that the center voltage at the low gray level is greater than the center voltage at the high gray level based on the second deviation data ΔVop2 data. That is, the second center voltage Vcenter2 corresponds to the second deviation data ΔVop2 data.

The second positive gamma curve and the second negative gamma curve of the second gamma data Vop2 data are adjusted based on the second center voltage Vcenter2. The second gamma data Vop2 data includes a second positive gamma curve and a second negative gamma curve symmetrical with respect to the second center voltage Vcenter2, and the second positive gamma curve and the second negative gamma curve correspond to a second common voltage ( Asymmetrical with respect to Vcom2). Here, since the second center voltage Vcenter2 is nonuniform and the second common voltage Vcom2 is uniform, flicker and long-term afterimages may be reduced in a stable state.

The maximum deviation value of the second deviation data ΔVop2 data may be equal to or less than 100 mV.

Here, the second positive gamma curve and the second negative gamma curve are symmetrical based on the second center voltage Vcenter2. Since the second center voltage Vcenter2 is a center value between the second positive gamma curve and the second negative gamma curve, when the second positive gamma curve and the second negative gamma curve are present, the second center voltage Vcenter2 may be calculated. The center voltage does not necessarily need to be stored as specific data. If there is a positive gamma curve and a negative gamma curve, the center voltage can be calculated and used as necessary. However, the present invention is not limited thereto, and data of the second center voltage Vcenter2 may be stored in a memory, and then loaded and used as necessary.

The first gamma data Vop1 data and the first common voltage data Vcom1 data are stored in the first bank 132, and the second gamma data Vop2 data and the second common voltage data () are stored in the second bank 134. The method of storing Vcom2 data) will be described later with reference to FIGS. 6 and 7.

Referring to FIG. 4 in conjunction with FIG. 4, the timing controller 120 includes a counter 122 capable of storing a predetermined switching time point for switching from an initial state to a stable state. The voltage control signal VCS may be generated by the timing controller 120 based on the switching time point.

Specifically, the switching time point represents the drive time information. The switching time from the initial state to the stable state is stored in the counter 122. The counter 122 may start counting from the start point of the initial state in which the liquid crystal display device 100 is turned on. When the switching time has elapsed, the counter 122 may determine that the liquid crystal display device 100 is in a stable state.

When the counter 122 confirms the switching timing of the liquid crystal display device 100, the timing controller 120 controls the turn-on and turn-off of the first bank 132 and the second bank 134. Generates a voltage control signal VCS. The voltage control signal VCS generated by the timing controller 120 may be supplied to the voltage generator 130.

The voltage control signal VCS may be output in an initial state when the liquid crystal display apparatus 100 is turned on, or may be output at the switching time point. The voltage control signal VCS may control the voltage generator 130 to output the first gamma voltage GMA1 and the first common voltage Vcom1. In addition, the voltage control signal VCS may output the second gamma voltage GMA2 and the second common voltage Vcom2. That is, the first gamma voltage GMA1 or the second gamma voltage GMA2 is selectively output by the voltage control signal VCS. The first common voltage Vcom1 or the second common voltage Vcom2 is selectively output by the voltage control signal VCS.

The voltage generator 130 controls turn-on and turn-off of the first bank 132 and the second bank 134 based on the voltage control signal VCS. In the initial state, the first bank 132 is turned on (activated) and the second bank 134 is turned off (disabled). Therefore, the voltage generator 130 may generate the first gamma voltage GMA1 and the first gamma based on the first gamma data Vop1 data and the first common voltage data Vcom1 data stored in the first bank 132. Each common voltage Vcom1 is generated. The first gamma voltage GMA1 and the first common voltage Vcom1 are output to the data driver 150. In other embodiments, the first common voltage Vcom1 may be directly output to the liquid crystal panel 110.

In the stable state, the second bank 134 is turned on and the first bank 132 is turned off. Therefore, the voltage generator 130 may generate the second gamma voltage GMA2 and the second gamma voltage based on the second gamma data Vop2 data and the second common voltage data Vcom2 data stored in the second bank 134. Each common voltage Vcom2 is generated. The second gamma voltage GMA2 and the second common voltage Vcom2 are output to the data driver 150. In other embodiments, the second common voltage Vcom2 may be directly output to the liquid crystal panel 110.

The common voltage shifter 124 included in the timing controller 120 is configured to operate in the gamma tuning process. For example, the common voltage shifter 124 operates when the second common voltage data Vcom2 data is stored in the second bank 134. However, the common voltage shifter 124 is configured not to operate when the liquid crystal display device 100 is being driven. This will be described in detail with reference to FIGS. 6 and 7.

As described with reference to FIGS. 4 and 5, the first common voltage Vcom1 and the first gamma voltage GMA1 are output to the data driver 150 in an initial state, and the second common voltage Vcom2 is in a stable state. And the second gamma voltage GMA2 are output to the data driver 150. To this end, the first gamma data Vop1 data and the first common voltage data Vcom1 data are stored in the first bank 132, and the second gamma data Vop2 data and the second common voltage data Vcom2 data. Is stored in the second bank 134.

Hereinafter, generating the first and second common voltages and the first and second gamma voltages will be described with reference to FIGS. 6 and 7.

4 and 6, first gamma data (Vop1 data) for generating a gamma voltage (first gamma voltage) in an initial state is generated during the manufacturing process of the liquid crystal display device 100, and the first gamma is generated. Data Vop data is stored in the first bank 132 of the voltage generator 130 (S11).

Second gamma data (Vop2 data) for generating a gamma voltage (second gamma voltage) in a stable state is generated, and the second gamma data (Vop2 data) is generated in the second bank 134 of the voltage generator 130. It is stored in (S12).

Subsequently, a voltage difference ΔVcom between the first common voltage Vcom1 and the second common voltage Vcom2 is calculated based on the first gamma data Vop1 data and the second gamma data Vop2 data. Is stored in the common voltage shifter 124 of the timing controller 120 (S13).

As the counting starts at the start of the initial state when the display device is turned on, the driving time from the initial state to the stable state is measured in consideration of the aging state of the liquid crystal display device 100 including the liquid crystal panel 110. do. The switching point (also referred to as S-time) is stored in the counter 122 of the timing controller 120 (S14).

4 and 7, the first common voltage data Vcom1 data optimized for the initial state is set in the final inspection step of the manufacturing process of the liquid crystal display apparatus 100. In this case, the first common voltage data Vcom1 data is stored in the first bank 132 of the voltage generator 130 (S21).

The common voltage difference ΔVcom is stored in the common voltage shifter 124, and the second common voltage data Vcom2 data is generated by applying the common voltage difference ΔVcom to the first common voltage data Vcom1 data. (S22).

Subsequently, the second common voltage data Vcom2 data optimized for the stable state is stored in the second bank 134 of the voltage generator 130 (S23).

Hereinafter, an example of supplying the first and second gamma voltages and the first and second common voltages when driving the liquid crystal display device 100 will be described in detail.

4 and 8, the liquid crystal display device 100 is initialized by turning on the liquid crystal display device 100. Accordingly, the timing controller 120 activates the first bank 132 of the voltage generator 130. At this time, the second bank 134 of the voltage generator 130 is deactivated. In order to generate the first gamma voltage GMA1, the first gamma data Vop1 data and the first common voltage data Vcom1 data stored in the first bank 132 are loaded (S31).

Subsequently, the first gamma voltage GMA1 is generated according to the first gamma data Vop data and output to the data driver 150. In addition, the first common voltage Vcom1 is generated according to the first common voltage data Vcom1 data loaded from the first bank 132 and output to the data driver 150 (S32). In another embodiment of the present invention, the first common voltage Vcom1 may be directly supplied to the liquid crystal panel 110.

The counter 122 starts counting so as to confirm the switching time from the initial state to the stable state (S33).

The counter 122 recognizes that the switching time has been switched from the initial state to the stable state when the switching time has elapsed. The counter 122 is configured to preset a switching time point for recognizing the aging state of the liquid crystal display device 100 as a stable state based on the elapsed driving time. The counter 122 may count the driving time from the moment the liquid crystal display 100 is turned on. The counter 122 recognizes that a stable state has started when a predetermined driving time elapses.

The timing controller 120 controls the turn-on / turn-off states of the first bank 132 and the second bank 134 of the voltage generator 130 based on the switching time from the initial state to the stable state. Generates a voltage control signal VCS. The timing controller 120 outputs the voltage control signal VCS to the voltage generator 130 (S34).

The voltage generator 130 activates the second bank 134 of the voltage generator 130 based on the voltage control signal VCS provided from the timing controller 120. At this time, the first bank 132 of the voltage generator 130 is deactivated. In order to generate the second gamma voltage GMA2, the second gamma data Vop2 data and the second common voltage data Vcom2 data stored in the second bank 134 are loaded (S35).

That is, when the current state of the liquid crystal display device 100 is switched to the stable state after a predetermined driving time, the second gamma data Vop2 data is applied to generate the second gamma voltage GMA2.

The second gamma voltage GMA2 in a stable state is generated according to the second gamma data Vo2 data and output to the data driver 150. In addition, the second common voltage Vcom2 is generated according to the second common voltage data Vcom2 loaded from the second bank 134 and output to the data driver 150 (S32). In another embodiment of the present invention, the second common voltage Vcom2 may be directly supplied to the liquid crystal panel 110.

The first common voltage Vcom1 corresponding to the first gamma voltage GMA1 and the second common voltage Vcom2 corresponding to the second gamma voltage GMA2 are different. However, the substantial potential difference in the pixel array of the liquid crystal panel 110 is the same in the initial state and the stable state. Therefore, the image quality of the liquid crystal display device 100 is substantially the same when comparing the image quality of the initial state and the stable state. That is, the liquid crystal display apparatus 100 may display substantially the same gray level regardless of the current state, and does not cause a problem such as deterioration of image quality.

Therefore, the timing controller 120 may provide an optimal common voltage in consideration of the aging state of the liquid crystal panel 110. For example, since the temperature of the liquid crystal panel 110 is lower at the start point of the initial state than the start point of the stable state, the reaction time characteristics of the liquid crystal layer differ according to the initial state and the stable state. The timing controller 120 provides the first common voltage Vcom1 and the first gamma voltage GMA1 for the initial state by the voltage control signal VCS, and the second common voltage Vcom2 and the first for the stable state. 2 gamma voltage GMA2 may be provided.

Flicker and substantially the same degree as the first common voltage Vcom1 and the first gamma voltage GMA1 in the initial state and the second common voltage Vcom2 and the second gamma voltage GMA2 in the stable state The same degree of afterimage may be provided. Substantially the same amount of flicker and substantially the same degree of afterimage can be said to be the same amount of flicker or afterimage in the initial state and in the stable state without the degree of afterimage or flicker being changed. Alternatively, the substantially same degree of flicker and the substantially same degree of afterimage include that the degree of afterimage or flicker is minimized in both the initial state and the stable state. Thus, high picture quality can be maintained in both the initial state and the stable state irrespective of the current state.

In the above description, only two banks (the first bank 132 and the second bank 134) are provided to store a plurality of gamma data, but the present invention is not limited thereto. . For example, two or more banks may be provided for multiple gamma data storage. In this case, different gamma data optimized for initial state and stable state may be supplied for generation of gamma voltage optimized for initial state and stable state.

FIG. 9 is a diagram illustrating an effect of improving display quality when a common voltage and a gamma voltage optimized for a short term (initial state) and a long term (stable state) are selectively applied according to a driving time.

Referring to FIG. 9, a first gamma voltage GMA1 and a first common voltage Vcom1 optimized for an initial state are generated based on an elapsed time of driving of the liquid crystal display device 100, and the liquid crystal display device 100 may be configured. The second gamma voltage GMA2 and the second common voltage Vcom2 optimized for the stable state are generated based on the elapsed driving time. Through this, it is possible to reduce the degree of variation of the flicker and the optimum common voltage. Accordingly, in the initial state, the liquid crystal display device 100 may suppress or reduce short-term afterimages by applying the first gamma voltage GMA1 and the first common voltage Vcom1. In the state, the long-term afterimage may be suppressed or reduced by applying the second gamma voltage GMA2 and the second common voltage Vcom2.

10 is a diagram illustrating a timing controller and a voltage generator in a liquid crystal display according to another exemplary embodiment of the present invention.

Referring to FIG. 10, a counter 122 may be built in the timing controller 120, and the common voltage shifter 124 illustrated in FIG. 4 may be removed from the timing controller 120. In the common voltage setting step illustrated in FIG. 7, the common voltage shifter 124 calculates a common voltage difference ΔVcom between the common voltage Vcom1 and the second common voltage Vcom2 to generate second common voltage data Vcom2 data. Is used to generate Therefore, the common voltage shifter 124 does not need to be embedded in the timing controller 120, and the common voltage shifter 124 is provided to the manufacturing equipment when the first and second common voltages are set, so that the second common voltage data Vcom2 data is provided. ) Can be created. Thereafter, the second common voltage data Vcom2 data may be stored in the second bank 134.

11 is a diagram illustrating a timing controller and a voltage generator in a liquid crystal display according to another exemplary embodiment of the present invention.

Referring to FIG. 11, the counter 122 may be built in the voltage generator 130. As shown in FIG. 8, the counter 122 is for recognizing a switching time from an initial state to a stable state, and recognizes that the liquid crystal display device has entered a stable state when a predetermined driving time elapses from the initial state. . The counter 122 may be provided to the voltage generator 130. The counter 122 is not embedded in the timing controller 120 or the voltage generator 130, and the counter 122 may be provided in a separate independent configuration.

12 is a view illustrating a timing controller and a voltage generator and a driving method thereof in the liquid crystal display according to the exemplary embodiment of the present invention.

Referring to FIG. 12, in the liquid crystal display device 100 according to an exemplary embodiment of the present disclosure, afterimage and flicker are reduced by changing the common voltage and the gamma voltage according to the driving time in accordance with the aging state of the liquid crystal panel 110. Let's do it.

Timing controller 120 includes a counter 122. The voltage generator 130 includes a plurality of banks. For example, the first common voltage data Vcom1 data and the first gamma data Vop1 data of the initial state are stored in the first bank 132. The second common voltage data Vcom2 data and the second gamma data Vop2 data in the stable state are stored in the second bank 134. The third common voltage data Vcom3 data and the third gamma data Vop3 data in the intermediate state are stored in the third bank 136.

The counter 122 of the timing controller 120 starts counting in an initial state and recognizes an intermediate state using a preset switching time point. Then, the voltage control signal VCS is generated and output according to the intermediate state. In this case, the driving time for switching from the initial state to the intermediate state is set and stored in the counter 122.

When the counter 122 detects that the liquid crystal display device 100 is in an intermediate state, the timing controller 120 turns on / off the first bank 132, the second bank 134, and the third bank 136. The voltage control signal VCS is generated by the timing controller 120 to generate the common voltage and gamma voltage optimized for the intermediate state. Supplied.

When the voltage control signal VCS is input to the voltage generator 130 for the intermediate state, the third common voltage Vcom3 data and the third gamma voltage GMA3 are converted to the liquid crystal panel according to the voltage control signal VCS. Supplied to 110.

Here, the first common voltage data Vcom1 data and the first gamma data Vop1 data are generated in the manufacturing process and stored in the first bank 132.

In addition, the second common voltage data Vcom2 data and the second gamma data Vop2 data are generated during the manufacturing process and stored in the second bank 134.

The third common voltage data Vcom3 data and the third gamma data Vop3 data are generated in the manufacturing process and stored in the third bank 136.

The first gamma data Vop1 data is stored in the first bank 132 to generate the first gamma voltage GMA1 in the initial state, and the second gamma data Vop2 data is the second gamma voltage in the stable state. The third gamma data Vop3 data is stored in the third bank 136 to generate the third gamma voltage GMA3 in an intermediate state.

The first common voltage data Vcom1 data is stored in the first bank 132 to generate the first common voltage Vcom1 in the initial state, and the second common voltage data Vcom2 data is the second common in the stable state. The third common voltage data Vcom3 data is stored in the third bank 136 to generate the voltage Vcom2, and the third common voltage data Vcom3 data is generated in the third bank 136 to generate the third common voltage Vcom3 in an intermediate state. will be.

Here, the intermediate state corresponds between the initial state and the stable state, which means that the liquid crystal panel 110 is in a state after the initial state and before reaching the stable state. The aging state of the liquid crystal panel 110 changes until it reaches a stable state. Therefore, it is also possible to add a common voltage and a gamma voltage optimized for the intermediate state.

In the liquid crystal display device 100 according to another exemplary embodiment, the third gamma voltage of the intermediate state is generated by using the third gamma data (Vop3 data) optimized for the intermediate state by reflecting the requirements in the intermediate state. (GMA3) can be generated. In addition, the third common voltage data Vcom3 data optimized for the intermediate state is stored in the third bank 136. The third common voltage Vcom3 is generated using the third common voltage data Vcom3 data stored in the third bank 136.

In order to generate an optimal common voltage for each gray level, the first gamma data Vop data, the second gamma data Vop2 data, and the third gamma data Vop3 data are determined. The optimum common voltage deviation (ΔVop) is less than 0V or 100mV.

If the optimum common voltage deviation (ΔVop) is less than 0 V or 100 mV, the optimum common voltage can be set at all gray levels, regardless of the gray level, so as to minimize the flicker in all grays to improve the afterimage problem. have.

Here, the first gamma voltage GMA1 in the initial state, the second gamma voltage GMA2 in the stable state, and the third gamma voltage GMA3 in the intermediate state may have different deviations with respect to each common voltage. However, the substantial potential difference in the pixels of the liquid crystal panel 110 is the same in the initial state, the stable state, and the intermediate state. Therefore, the image quality of the liquid crystal display device 100 is substantially the same when comparing the image quality of the initial state, the stable state, and the intermediate state. That is, the liquid crystal display apparatus 100 may display substantially the same gray level regardless of the current state, and thus may prevent or minimize deterioration of image quality.

In some embodiments, there may be multiple intermediate states. For example, the intermediate state may further include a first intermediate state and a second intermediate state.

The present invention can be summarized once again as follows.

The liquid crystal panel according to some embodiments of the present invention can suppress the flicker degree and the short-term afterimage when the first gamma voltage and the first common voltage are received, and the flicker when the second gamma voltage and the second common voltage are received. A pixel array capable of suppressing degree and long-term afterimage, wherein a first gamma voltage is received during an initial state and a second gamma voltage is received during a stable state, and the initial state is switched to a stable state based on a predetermined switching time point. The first gamma voltage is generated using first gamma data including a first positive gamma curve and a first negative gamma curve based on the first center voltage, and the first positive gamma curve and the first negative gamma curve are generated. The first center voltage symmetrical with respect to the first center voltage and corresponding to all gray levels is nonuniform, and the second gamma voltage is a second positive gamma marker based on the second center voltage. And second gamma data including a second negative gamma curve, wherein the second positive gamma curve and the second negative gamma curve are symmetric with respect to the second center voltage and correspond to all gray levels. Is characterized by non-uniformity.

The first common voltage is determined based on the first deviation data, the second common voltage is determined based on the second deviation data, and the first and second deviation data have a relatively high degree of deviation at a relatively low gray level. It is characterized by being larger than the degree of deviation in the gray level. The first common voltage is higher than the second common voltage. The first gamma voltage is higher than the second gamma voltage, and the voltage difference between the first gamma voltage and the second gamma voltage is substantially the same in the pixel array. The voltage at the relatively low gray level of the first center voltage is greater than the voltage at the relatively high gray level of the first center voltage. The maximum deviation value of the first and second deviation data is characterized in that less than 0V or 100mV. The duration of the initial state is based on the aging state of the liquid crystal panel, and the predetermined switching time point is determined according to the initial state duration, and the first gamma voltage, the first common voltage, the second gamma voltage and the second common voltage are adjusted. It is characterized in that the flicker degree, short-term afterimage and long-term afterimage in the initial state and the stable state are substantially the same.

The liquid crystal display device according to some embodiments of the present invention may receive a timing controller and a voltage control signal capable of generating a voltage control signal for switching from an initial state to a stable state using a predetermined switching time point. A first gamma voltage and a first common voltage may be supplied in an initial state, a voltage generator capable of supplying a second gamma voltage and a second common voltage in a stable state, and may receive a first gamma voltage in an initial state, In the stable state, the data driver capable of receiving the second gamma voltage and the short-term afterimage when the first gamma voltage and the first common voltage are applied can be suppressed, and the long-term afterimage is applied when the second gamma voltage and the second common voltage are applied. And a liquid crystal panel comprising a pixel array that can be suppressed.

The voltage generator includes at least a first bank capable of storing the first gamma data and the first common voltage data, and a second bank capable of storing the second gamma data and the second common voltage data, wherein the first gamma voltage is defined by the first gamma voltage. Generated based on the gamma data and the second gamma voltage is generated based on the second gamma data, the first common voltage is generated based on the first common voltage data, and the second common voltage is based on the second common voltage data. It is characterized in that the generated. And a third bank, wherein the timing controller is configured to control the voltage to switch the intermediate state to the stable state using the predetermined second switching time point after switching the initial state to the intermediate state using the predetermined first switching time point. The signal generator may generate a signal, the voltage generator may supply a third gamma voltage and a third common voltage during an intermediate state, and the third bank may store the third gamma data and the third common voltage data, and the third gamma The voltage may be generated based on the third gamma data, and the third common voltage may be generated based on the third common voltage data. The first common voltage is the same at all gray levels, the first gamma data includes a first positive gamma curve and a first negative gamma curve, and the first positive gamma curve and the first negative gamma curve are with respect to the first common voltage. It is characterized by being asymmetric. The second common voltage is the same at all gray levels, the second gamma data includes a second positive gamma curve and a second negative gamma curve, and the second positive gamma curve and the second negative gamma curve are with respect to the second common voltage. It is characterized by being asymmetric. The first common voltage and the second common voltage are different, and the first gamma data and the second gamma data are different. The switching time point is determined by the driving time of the liquid crystal panel.

The driving method of the liquid crystal display apparatus may include generating, by a timing controller, a voltage control signal for switching from an initial state to a stable state using a predetermined switching time point, and wherein the voltage generation unit receives the voltage control signal, Supplying a first gamma voltage and a first common voltage and supplying a second gamma voltage and a second common voltage during a stable state; the data driver receives the first gamma voltage during an initial state and a second gamma voltage during the stable state. The liquid crystal panel including the receiving step and the pixel array is driven to suppress short-term afterimage when the first gamma voltage and the first common voltage are applied, and suppress long-term afterimage when the second gamma voltage and the second common voltage are applied. It is characterized by.

According to the present invention, the afterimage of the initial state can be reduced or eliminated by adjusting the common voltage and the gamma voltage according to the driving time.

In addition, since the final inspection time including afterimage inspection can be shortened by adjusting the common voltage and the gamma voltage according to the driving time, manufacturing cost or manufacturing time can be reduced, and after-image or flicker is reduced, manufacturing efficiency can be improved. have.

Those skilled in the art to which the present invention pertains will understand that the above-described present invention can be implemented in other specific forms without changing the technical spirit or essential features. Therefore, it is to be understood that the embodiments described above are exemplary in all respects and not restrictive. The scope of the present invention is shown by the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention. do.

Claims

A pixel array capable of suppressing flicker degree and short-term afterimage when the first gamma voltage and the first common voltage are received, and suppressing the flicker degree and long-term afterimage when the second gamma voltage and the second common voltage are received, Including,

The first gamma voltage is received during the initial state and the second gamma voltage is received during the stable state, the initial state is switched to the stable state based on a predetermined switching time point,

The first gamma voltage is generated using first gamma data including a first positive gamma curve and a first negative gamma curve based on a first center voltage.

The first positive gamma curve and the first negative gamma curve are symmetric with respect to the first center voltage,

The first center voltage corresponding to all gray levels is nonuniform,

The second gamma voltage is generated using second gamma data including a second positive gamma curve and a second negative gamma curve based on a second center voltage.

The second positive gamma curve and the second negative gamma curve are symmetric with respect to the second center voltage;

The second center voltage corresponding to all gray levels is nonuniform,

Liquid crystal panel.
According to claim 1,

The first common voltage is determined based on first deviation data, and the second common voltage is determined based on second deviation data,

Wherein the first and second deviation data have a degree of deviation at a relatively low gray level being greater than a degree of deviation at a relatively high gray level,

Liquid crystal panel.
According to claim 1,

The first common voltage is higher than the second common voltage,

Liquid crystal panel.
The method of claim 3, wherein

The first gamma voltage is higher than the second gamma voltage,

A voltage difference between the first gamma voltage and the second gamma voltage is substantially the same in the pixel array;

Liquid crystal panel.
According to claim 1,

The voltage at the relatively low gray level of the first center voltage is greater than the voltage at the relatively high gray level of the first center voltage,

Liquid crystal panel.
The method of claim 2,

The maximum deviation value of the first and second deviation data is less than 0V or 100mV,

Liquid crystal panel.
According to claim 1,

The duration of the initial state is based on the aging state of the liquid crystal panel,

The predetermined switching time point is determined according to the initial state duration,

By adjusting the first gamma voltage, the first common voltage, the second gamma voltage and the second common voltage, the flicker degree, the short-term afterimage and the long-term afterimage in the initial state and the stable state are substantially reduced. same,

Liquid crystal panel.
A timing controller capable of generating a voltage control signal for switching from an initial state to a stable state using a predetermined switching time point;

A voltage generator capable of receiving the voltage control signal, supplying a first gamma voltage and a first common voltage during the initial state, and supplying a second gamma voltage and a second common voltage during the stable state;

A data driver capable of receiving the first gamma voltage during the initial state and receiving the second gamma voltage during the stable state; And

And a liquid crystal panel including a pixel array capable of suppressing short-term afterimage when the first gamma voltage and the first common voltage are applied and suppressing long-term afterimage when the second gamma voltage and the second common voltage are applied. Comprising;

Liquid crystal display device.
The method of claim 8,

The voltage generator includes at least a first bank capable of storing first gamma data and first common voltage data, and a second bank capable of storing second gamma data and second common voltage data.

The first gamma voltage is generated based on the first gamma data, and the second gamma voltage is generated based on the second gamma data,

Wherein the first common voltage is generated based on the first common voltage data and the second common voltage is generated based on the second common voltage data.

Liquid crystal display device.
The method of claim 9,

Further comprising a third bank,

The timing controller generates the voltage control signal for switching the initial state to an intermediate state by using a predetermined first switching time point and then switching the intermediate state to the stable state by using a predetermined second switching time point. Can do it,

The voltage generator may supply a third gamma voltage and a third common voltage during the intermediate state.

The third bank may store third gamma data and the third common voltage data.

The third gamma voltage may be generated based on the third gamma data.

The third common voltage may be generated based on the third common voltage data.

Liquid crystal display device.
The method of claim 9,

The first common voltage is the same at all gray levels,

The first gamma data includes a first positive gamma curve and a first negative gamma curve,

Wherein the first positive gamma curve and the first negative gamma curve are asymmetrical with respect to the first common voltage.

Liquid crystal display device.
The method of claim 11, wherein

The second common voltage is the same at all gray levels,

The second gamma data includes a second positive gamma curve and a second negative gamma curve,

Wherein the second positive gamma curve and the second negative gamma curve are asymmetrical with respect to the second common voltage.

Liquid crystal display device.
The method of claim 12,

The first common voltage and the second common voltage are different;

Wherein the first gamma data and the second gamma data are different,

Liquid crystal display device.
The method of claim 13,

The switching time point is determined according to the driving time of the liquid crystal panel,

Liquid crystal display device.
Generating, by the timing controller, a voltage control signal for switching from an initial state to a stable state using a predetermined switching time point;

Receiving, by the voltage generator, the voltage control signal and supplying a first gamma voltage and a first common voltage during the initial state and a second gamma voltage and a second common voltage during the stable state;

Receiving, by a data driver, the first gamma voltage during the initial state and the second gamma voltage during the stable state; And

In the liquid crystal panel including the pixel array, the step of suppressing short-term afterimage when the first gamma voltage and the first common voltage are applied, and the long-term afterimage when the second gamma voltage and the second common voltage are applied are suppressed. Included,

Method of driving a liquid crystal display device.