KR20180058928A - Display device and method for driving thereof - Google Patents

Abstract

The present invention relates to a display device and a driving method of a display device, which use a lower or higher gradation than that of an image frame to display an image when the gradation of the image frame is the maximum or minimum gradation, so as to apply overdriving in all gradations, thereby reducing a response time and increasing display quality of a moving picture. Moreover, an overdriving application mode is adjusted in a section close to the maximum or minimum gradation, thus preventing a gradation inversion effect due to overdriving application in the maximum or minimum gradation. Moreover, an average brightness level is considered when overdriving is applied in the minimum gradation, thereby increasing the display quality through the overdriving application in a range from which a gradation difference is not recognized. According to the present invention, the display device comprises a display panel, a gate driver, and a data driver.

Description

TECHNICAL FIELD [0001] The present invention relates to a display device and a method of driving the same,

The embodiments relate to a display device and a driving method of the display device.

2. Description of the Related Art Various kinds of display devices such as a liquid crystal display device, a plasma display device, and an organic light emitting display device have been utilized.

Among such display devices, a liquid crystal display device displays an image by adjusting a light transmittance of a liquid crystal through a thin film transistor which is a switching device. Such a liquid crystal display device is being applied to various products such as a portable information device, an office machine, and a computer because of advantages such as light weight, thinness and low power consumption driving.

Since such a liquid crystal display device is not a self-luminous device, an image is displayed using light supplied through a backlight unit disposed under the liquid crystal panel. When the transmittance of light of the liquid crystal layer of the liquid crystal panel is maximized, the liquid crystal panel displays a white image with high brightness. When the transmittance of light of the liquid crystal layer is minimized, the liquid crystal panel displays a black image of low brightness.

Such a liquid crystal display device is driven at 60 to 240 frames per second according to the driving frequency, thereby displaying moving images. At this time, there is a problem that a motion blur phenomenon occurs in which a residual image of a previous frame affects a next frame due to a hold characteristic of a light source generating light and a liquid crystal holding property.

Such a motion blur phenomenon causes a problem that the moving picture response time (MPRT) of the liquid crystal display device is reduced and the display quality of the liquid crystal display device is deteriorated.

It is an object of the present embodiments to provide a display device and a driving method thereof capable of improving a moving picture response time (MPRT) when a difference between a gray level of an image frame and a gray level of a previous gray level is large.

It is an object of the present embodiments to provide a display device and a driving method thereof that can improve a moving picture response time (MPRT) by applying over driving regardless of the gradation of an image frame.

In one aspect, the present embodiments provide a display device including a display panel on which a plurality of gate lines, a plurality of data lines and a plurality of subpixels are arranged, a gate driver for outputting scan signals to a plurality of gate lines, And a data driver for outputting a voltage.

In this display device, the data driver applies overdriving in the Nth image frame if the difference between the gradation of the (N-1) th image frame and the gradation of the Nth image frame is greater than a predetermined difference.

At this time, the data driver outputs the data voltage corresponding to the maximum gradation in the first section of the image frame when the gradation of the image frame is higher than the preset gradation at the time of overdriving, and outputs the gradation of the image frame in the second section after the first section And outputs a data voltage corresponding to a lower gradation.

For example, the data driver outputs a data voltage corresponding to the maximum gradation in the first period of the image frame when the gradation of the image frame corresponds to the maximum gradation, and outputs data corresponding to the gradation lower than the maximum gradation in the second section of the image frame Voltage can be output.

Alternatively, the data driver outputs a data voltage corresponding to the lowest gradation in the first section of the image frame when the gradation of the image frame is lower than the preset gradation in overdriving application, and outputs the data voltage corresponding to the lowest gradation in the second section after the first section And outputs a data voltage corresponding to a gray level higher than the gray level.

For example, if the gradation of the image frame corresponds to the lowest gradation, the data driver outputs the data voltage corresponding to the lowest gradation in the first section of the image frame and the data corresponding to the gradation higher than the lowest gradation in the second section of the image frame Voltage can be output.

Here, the data driver may output a data voltage corresponding to a preset gradation in a second section of the image frame, and the level of the data voltage output by the data driver in the second section of the image frame may be the same can do.

Alternatively, the level of the data voltage that the data driver outputs in the second period of the video frame may gradually decrease or increase in proportion to the grayscale of the video frame, and the level of some data voltages may be the same.

If the gray level of the video frame is lower than the preset gray level, the data driver outputs the data voltage corresponding to the lowest gray level in the first section of the video frame, and if the average brightness level is higher than the predetermined level in the video frame, A data voltage corresponding to a gray level higher than a gray level of an image frame is output.

If the average luminance level in the image frame is equal to or less than the preset level, the data voltage corresponding to the gray level of the image frame can be output in the first and second sections of the image frame.

According to another aspect of the present invention, there is provided a display device including: checking whether a gradation of an image frame is within a preset range when overdriving is applied; And outputting a data voltage corresponding to a gray level higher than the gray level of the video frame or the gray level of the video frame in the second period of the video frame, And outputting a voltage.

According to the embodiments, when the gradation of the image frame is the maximum gradation or the lowest gradation, the data voltage corresponding to the maximum or the lowest gradation in the overdriving period is outputted, and the gradation lower than the highest gradation or the gradation higher than the lowest gradation The corresponding data voltage is outputted so that overdriving can be applied irrespective of the gradation of the image frame.

In addition, the overdriving application method for some gradations is changed according to the overdriving application for the maximum gradation or the lowest gradation, thereby enabling the overdriving driving without the gradation reversal phenomenon.

In addition, by applying overdriving in consideration of the average luminance level, the moving picture response time (MPRT) can be improved and the cognitive characteristics can be maintained.

1 is a diagram showing a schematic configuration of a display device according to the present embodiments.
2A and 2B are views showing an example of a method of applying overdriving in a display device according to the present embodiments.
Figs. 3A, 3B, 4A and 4B are diagrams showing examples of a method of applying overdriving in the maximum gradation and the lowest gradation in the display device according to the present embodiments.
FIGS. 5A and 5B are views showing examples of output data when overdriving is applied to the maximum gradation and the lowest gradation in the display device according to the present embodiments.
6A and 6B are diagrams illustrating another example of output data when overdriving is applied to the maximum gradation and the lowest gradation in the display device according to the present embodiments.
7 is a flowchart illustrating a method of driving a display device according to an embodiment of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. In the drawings, like reference numerals are used to denote like elements throughout the drawings, even if they are shown on different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

In describing the components of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are intended to distinguish the components from other components, and the terms do not limit the nature, order, order, or number of the components. When a component is described as being "connected", "coupled", or "connected" to another component, the component may be directly connected or connected to the other component, Quot; intervening "or that each component may be" connected, "" coupled, "or " connected" through other components.

Fig. 1 shows a schematic configuration of a display device 100 according to the present embodiments.

Referring to FIG. 1, a display device 100 according to the present embodiment includes a plurality of gate lines GL and a plurality of data lines DL, a gate line GL and a data line DL, And a display panel 110 including a plurality of sub-pixels arranged in a region where the sub-pixels are arranged. A data driver 130 for supplying a data voltage to a plurality of data lines DL and a data driver 130 for driving the gate driver 120 and the data driver 130. The gate driver 120 drives the plurality of gate lines GL, And a controller 140 for controlling the driving of the motor.

The gate driver 120 sequentially drives the plurality of gate lines GL by sequentially supplying scan signals (gate signals) to the plurality of gate lines GL.

The gate driver 120 sequentially supplies gate signals of an ON voltage or an OFF voltage to the plurality of gate lines GL under the control of the controller 140 to sequentially supply a plurality of gate lines GL And sequentially driven.

The gate driver 120 may be located on only one side of the display panel 110 or on both sides of the display panel 110 according to the driving method.

In addition, the gate driver 120 may include one or more gate driver integrated circuits.

Each gate driver integrated circuit may be connected to a bonding pad of the display panel 110 by a tape automated bonding (TAB) method or a chip on glass (COG) method, or may be connected to a GIP Gate In Panel) type and can be disposed directly on the display panel 110. [

In addition, they may be integrated on the display panel 110, or may be implemented by a chip on film (COF) method, which is mounted on a film connected to the display panel 110.

The data driver 130 drives the plurality of data lines DL by supplying data voltages to the plurality of data lines DL.

The data driver 130 converts image data received from the controller 140 into analog data voltages and supplies the image data to the plurality of data lines DL so that a plurality of data lines DL are formed. .

The data driver 130 may include at least one source driver integrated circuit to drive a plurality of data lines DL.

Each source driver integrated circuit may be connected to a bonding pad of the display panel 110 by a tape automated bonding (TAB) method or a chip on glass (COG) method, The display panel 110 may be directly disposed on the display panel 110 or integrated on the display panel 110.

In addition, each source driver integrated circuit may be implemented by a chip on film (COF) method. In this case, one end of each source driver integrated circuit is bonded to at least one source printed circuit board, and the other end is bonded to the display panel 110.

The controller 140 supplies various control signals to the gate driver 120 and the data driver 130 to control the gate driver 120 and the data driver 130.

The controller 140 starts scanning according to the timing implemented in each frame, switches the input image data input from the outside according to the data signal format used by the data driver 130, and outputs the converted image data , And controls the data driving at a proper time according to the scan.

The controller 140 outputs various timing signals including a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, an input data enable (DE) signal, and a clock signal (CLK) From an external (e.g., host system).

The controller 140 outputs the switched image data by switching the input image data inputted from the outside according to the data signal format used by the data driver 130 and outputs the converted image data to the gate driver 120 and the data driver 130, A timing signal such as a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, an input data enable signal DE and a clock signal CLK to generate various control signals, 120, and the data driver 130, respectively.

For example, to control the gate driver 120, the controller 140 may include a gate start pulse (GSP), a gate shift clock (GSC), a gate output enable signal GOE Gate Output Enable), and the like.

Here, the gate start pulse GSP controls the operation start timing of one or more gate driver integrated circuits constituting the gate driver 120. The gate shift clock GSC is a clock signal commonly input to one or more gate driver integrated circuits, and controls the shift timing of the gate signal. The gate output enable signal GOE specifies the timing information of one or more gate driver ICs.

In order to control the data driver 130, the controller 140 may further include a source start pulse (SSP), a source sampling clock (SSC), and a source output enable signal (SOE) And outputs various data control signals (DCS: Data Control Signals).

Here, the source start pulse SSP controls the data sampling start timing of one or more source driver integrated circuits constituting the data driver 130. The source sampling clock SSC is a clock signal for controlling sampling timing of data in each of the source driver integrated circuits. The source output enable signal SOE controls the output timing of the data driver 130.

The controller 140 is connected to a source printed circuit board to which a source driver integrated circuit is bonded and a control printed circuit board (not shown) connected via a connection medium such as a flexible flat cable (FFC) or a flexible printed circuit (Control Printed Circuit Board).

A power controller (not shown) for controlling various voltages or currents to supply or supply various voltages or currents to the display panel 110, the gate driver 120, the data driver 130, . These power controllers are also referred to as power management ICs.

Meanwhile, in the case of displaying a moving image through the display panel 110, the display device 100 has a problem that the display quality may be lowered due to a residual image or the like displayed on the display panel 110, compared with a case of displaying a still image .

Particularly, when the gradation of the image frame is larger than the gradation of the previous image frame, the response time is slow and the moving image response time (MPRT) is lowered and the display quality is degraded.

The display device 100 according to the present embodiments provides a method for improving the moving picture response time (MPRT) by adjusting a partial output of the data voltage when the difference in gradation between successive image frames is large.

FIGS. 2A and 2B illustrate a method of improving the moving picture response time (MPRT) by applying over driving to a data voltage corresponding to a gray level of an image frame according to the embodiments of the present invention , And a case of a liquid crystal display device is shown as an example.

2A shows a method of applying overdriving when the gradation of an image frame is changed from a low gradation to a high gradation.

Referring to FIG. 2A, the display apparatus 100 according to the present embodiment, when the gradation of an image frame changes from a low gradation to a high gradation and a gradation difference between image frames is large, .

For example, a data voltage higher than a data voltage corresponding to a gray level of an image frame is output (Overdriving) in a first period of an image frame (nth frame), and a data voltage (Data).

By outputting a data voltage higher than the data voltage corresponding to the gray level of the image frame in the first section of the image frame, it is possible to improve the response speed which is slowed down when the gray level difference between image frames is large.

Also, by outputting the data voltage corresponding to the gray level of the image frame in the second section of the image frame, the response speed is improved and the image corresponding to the gray level of the image frame can be displayed in the corresponding image frame.

FIG. 2B shows a method of applying overdriving when the gradation of an image frame changes from a high gradation to a low gradation.

Referring to FIG. 2B, when the gradation of an image frame changes from a high gradation to a low gradation and a gradation difference between image frames is large, the display device 100 according to the present exemplary embodiment displays a data voltage .

As shown in FIG. 2B, a data voltage lower than the data voltage corresponding to the gradation of the image frame is output (Overdriving) in the first section of the image frame (nth frame), and the gradation (Data).

By outputting a data voltage lower than the data voltage corresponding to the gradation of the image frame in the first section of the image frame, the response speed can be rapidly obtained even when the difference in gradation between image frames is large.

By outputting a data voltage corresponding to the gradation of the image frame in the second section of the image frame, the response speed is improved and the gradation of the image frame can be expressed.

However, if the gray level of the image frame is the maximum gray level or the lowest gray level, overdriving may be performed. There is a problem that can not be applied.

FIGS. 3A and 3B show waveforms of data voltages to be outputted when the gradation of the image frame is the maximum gradation or the lowest gradation. In this example, the gradation of the image frame is 0G to 255G.

FIG. 3A shows the data voltage output and the response speed of the liquid crystal when the gray level of the image frame is the maximum gray level.

Referring to FIG. 3A, when the gradation of an image frame is changed from 0G, which is the lowest gradation, to 255G, which is the maximum gradation, the gradation difference between image frames is large, so that the response speed of the liquid crystal is slowed down.

As a result, the moving picture response time (MPRT) increases and an image abnormality such as a residual image is generated through the display panel 110, thereby deteriorating display quality.

FIG. 3B shows the data voltage output and the response speed of the liquid crystal when the gradation of the image frame is the lowest gradation.

Referring to FIG. 3B, when the gradation of the image frame is changed from 255 G, which is the maximum gradation, to 0 G, which is the lowest gradation, the gradation difference between image frames is large, so that the response speed of the liquid crystal is slowed down.

Therefore, as in the case where the gradation of the image frame is changed from the lowest gradation to the highest gradation, the moving image response time MPRT increases and the display quality of the image displayed through the display panel 110 decreases.

If the gradation of the image frame is the maximum gradation or the lowest gradation, overdriving can not be applied and the moving image response time (MPRT) can not be improved.

In addition, there is a problem that the range of the output voltage of the data driver 130 must be extended in order to apply the overdriving even when the gradation of the image frame is the maximum gradation or the lowest gradation.

The display device 100 according to the present embodiments provides a method of improving the moving picture response time (MPRT) through overdriving application even when the gradation of the image frame is the maximum gradation or the lowest gradation.

4A and 4B show a method of applying overdriving when the gradation of an image frame in the display device 100 according to the present embodiment is the maximum gradation or the lowest gradation.

4A shows that overdriving is applied when the gradation of the image frame is the maximum gradation.

Referring to FIG. 4A, when the gradation of an image frame changes from a low gradation to a high gradation and the gradation of an image frame corresponds to 255G, which is the maximum gradation, the display device 100 according to the present embodiment 1, the data voltage corresponding to the maximum gradation of 255 G is output.

In the second period of the video frame, the data voltage corresponding to 255G-a, which is lower than the maximum gradation, is output.

That is, when the grayscale of the video frame is close to the maximum grayscale, the maximum grayscale of the video frame is used for overdriving and the data voltage corresponding to the grayscale lower than the actual grayscale of the video frame Used for image display.

Accordingly, in the first period of the image frame, the data voltage corresponding to the maximum gradation of 255G is output to speed up the response speed of the liquid crystal. In the second period of the image frame, the gradation of 255G-a To output an image corresponding to 255G-a.

Since 255G-a adjacent to 255G can not recognize the difference in gradation, the display quality according to the gradation of the image frame is maintained, and the response time of the liquid crystal is increased, so that the moving picture response time (MPRT) So that it can be improved.

At this time, since the data voltage corresponding to the gray level lower than the maximum gray level is outputted in the image frame having the maximum gray level, the gray level inversion phenomenon may occur at the gray level lower than the maximum gray level adjacent to the maximum gray level.

The display device 100 according to the present embodiment adjusts the overdriving method for the gradation between the gradations corresponding to the data voltages outputted from the maximum gradation and the maximum gradation image data, It is possible to prevent the grayscale inversion phenomenon according to the present invention.

For example, when overdriving is applied to an image frame of 255G, the output data voltage is changed from 255G to 255G-a. Therefore, the overdriving method for the gradation between 255G and 255G-a is the over-driving method for the gradation of 255G- .

For example, if the gradation of the image frame is higher than the predetermined gradation 255G-a, the data voltage corresponding to the maximum gradation of 255G in the first section of the image frame is output during overdriving and 255G-a And outputs the data voltage.

If the gradation of the image frame is higher than the preset gradation, overdriving is applied in the same way, so that the gradation reversal phenomenon due to overdriving application can be prevented in the gradation between 255G and 255G-a.

As another example, if the gradation of the image frame is higher than 255G-a, overdriving may be applied in proportion to the gradation of the image frame, but the output voltages for some gradations may be overlapped.

That is, as the gradation of the image frame gradually increases from 255 G to 255 G-a, some output data voltages are superimposed and gradually decreased, so that the over-driving can be applied while maintaining the gradation difference of the image frame to some extent.

The method of applying overdriving at the maximum gradation can be applied to the case where the gradation of the image frame is changed from a high gradation to a low gradation.

FIG. 4B shows a method in which overdriving is applied when the gradation of the image frame is the lowest gradation.

Referring to FIG. 4B, there is shown a case where the gradation of an image frame changes from a high gradation to a low gradation and is changed to 0G.

The display apparatus 100 according to the present embodiment outputs a data voltage corresponding to 0 G which is the lowest gray level in the first section of the image frame in order to apply overdriving when the gray level of the image frame is changed to the low gray level .

Then, a data voltage corresponding to 0G + b higher than the grayscale of the video frame is output in the second section of the video frame.

Accordingly, when the gradation of the image frame is the lowest gradation, the overdriving is applied to the data voltage corresponding to 0G and the data voltage corresponding to 0G + b is output to display the image.

Gradation differences between 0G and 0G + b are not well understood, so the display quality is maintained and the video response time (MPRT) can be improved through overdriving.

Even when the gradation of the image frame is a low gradation, overdriving is similarly applied in the gradation between 0G and 0G + b, or the overdriving voltage is gradually increased, Thereby preventing the grayscale inversion phenomenon due to the application.

Further, when overdriving is applied in a low gradation, since the gradation difference can be recognized according to the average picture level (APL), it is possible to control whether overdriving is applied in a low gradation according to the average brightness level APL .

For example, when the average luminance level (APL) is high in the entire image including the image frame, the difference between 0G and 0G + b is not recognized. Therefore, overdriving is applied to overdriving even the lowest gradation image frame To be applied.

When the average luminance level APL is low, the difference between 0G and 0G + b can be recognized. Therefore, the overdriving is not applied and the first and second sections of the image frame correspond to the gradations of the image frame Thereby outputting the data voltage.

Therefore, according to the present embodiments, it is possible to improve the moving picture response time (MPRT) through overdriving application even when the gradation of the image frame is the maximum gradation or the lowest gradation, and when the image frame is the lowest gradation, The overdriving is applied in consideration of the level (APL) so that the display quality can be maintained.

Hereinafter, with reference to FIG. 5A to FIG. 6B, a method of changing overdriving in the gradation nearest to the maximum gradation or the lowest gradation according to the overdriving application in the maximum gradation or the lowest gradation will be described.

5A and 5B show examples in which the overdriving in the gradation adjacent to the maximum gradation or the lowest gradation is applied in the same manner according to the overdriving application in the maximum gradation and the lowest gradation in the display device 100 according to the present embodiments will be.

5A shows that overdriving is applied to every gradation of an image frame in a section where the gradation of the image frame is higher than a predetermined gradation (for example, 223G) when the gradation of the image frame is changed from the low gradation to the high gradation.

Referring to 501 of FIG. 5A, if the gray level of the image frame is higher than the preset gray level of 223G, the data voltage corresponding to the maximum gray level of 255 G is output in the first period of the image frame for over driving.

In the second period of the video frame, the data voltage corresponding to the predetermined gray level of 223G is output.

Therefore, when the gradation of the image frame changes from a low gradation to a high gradation and is higher than a preset gradation of 223G, the response speed is rapidly brought to a data voltage corresponding to 255G for each gradation of each image frame, To display an image.

Since the difference in the perception characteristics is not large in the gradation adjacent to the maximum gradation 255G, the overdriving and the image display are respectively performed with the data voltages corresponding to the same gradation, thereby improving the moving picture response time (MPRT) and improving the display quality .

The overdriving is applied to the data voltages corresponding to the gradations higher than the respective gradations in the gradation of 223 G or less, which is the predetermined gradation, and an image is displayed with the data voltage corresponding to each gradation to improve the response speed and display the correct gradation (502 in FIG. 5A).

FIG. 5B shows that overdriving is applied to every gradation of an image frame in a period in which the gradation of an image frame is changed from a high gradation to a low gradation and in a period lower than a predetermined gradation (for example, 31G).

Referring to 503 of FIG. 5B, when the gray level of the image frame corresponds to a gray level lower than 31G, a data voltage corresponding to 0G is output in the first period of the image frame for over driving, And outputs the data voltage corresponding to the set gradation 31G.

The overdriving is applied to the data voltage corresponding to 0G which is the lowest gradation in the section adjacent to 0G in which the gradation of the image frame is the lowest gradation to speed up the response speed.

Then, the image is displayed with the data voltage corresponding to 31G which is not well recognized between 0G and gradation difference, so that the response speed is fast and the display quality can be maintained.

In the interval of 31 G or more, which is a preset gray level, overdriving is applied to the data voltage corresponding to the gray level lower than the gray level of the video frame in the first section of the video frame, and the data corresponding to the gray level of the video frame So that the video response time (MPRT) is improved, and the image of the correct gradation is displayed (504 in FIG. 5B).

6A and 6B show an example in which the overdriving in the gradation nearest to the maximum gradation or the lowest gradation is gradually applied according to the overdriving application in the maximum gradation and the lowest gradation in the display apparatus 100 according to the present embodiments will be.

6A shows a method of gradually applying overdriving in a period in which the gradation of an image frame changes from a low gradation to a high gradation and is higher than a preset gradation (for example, 237G).

Referring to 601 in FIG. 6A, when the gray level of the image frame is 255 G, which is the maximum gray level, overdriving is applied to the data voltage corresponding to 255 G, and an image is displayed with a data voltage corresponding to 240 G. In the case of 254G, overdriving is applied in the same manner as 255G.

If the grayscale of the image frame is 245G, the overdriving is applied to the data voltage corresponding to 253G and the image is displayed with the data voltage corresponding to 238G.

When the grayscale of the image frame is 240 G, overdriving is applied to the data voltage corresponding to 252 G and the image is displayed with the data voltage corresponding to 237 G.

In the section where the gradation of the image frame is 237 G or less, overdriving is applied to the data voltage corresponding to the gradation higher than the gradation of the image frame, and the image is displayed with the data voltage corresponding to the gradation of the image frame (602 in FIG. 6A) .

Accordingly, it is possible to display an image by gradually changing the gradation within the adjacent section while displaying the image using the gradation lower than the gradation of the image frame in the interval where the gradation of the image frame is adjacent to the maximum gradation, .

6B shows a method of gradually applying overdriving in a period in which the gradation of an image frame changes from a high gradation to a low gradation and is lower than a preset gradation (for example, 19G).

Referring to 603 of FIG. 6B, when the grayscale of an image frame is 0G, overdriving is applied to a data voltage corresponding to 0G and an image is displayed with a data voltage corresponding to 16G.

When the grayscale of the image frame is 1G, overdriving is applied to the data voltage corresponding to 0G and the image is displayed with the data voltage corresponding to 16G as in the case of 0G.

If the gradation of the image frame is 10G, the overdriving is applied to the data voltage corresponding to 2G and the image is displayed with the data voltage corresponding to 18G. If the gradation of the image frame corresponds to 15G, the data voltage To overdrive and display the image with a data voltage of 19G.

Accordingly, overdriving is possible by displaying an image with a higher gradation than the gradation of the image frame in the interval in which the gradation of the image frame is adjacent to the lowest gradation, so that the image can be displayed by gradually changing the gradation in the section adjacent to the lowest gradation do.

In a period in which the gradation of the image frame is 19 G or more, which is the preset gradation, overdriving is applied to the data voltage corresponding to the gradation lower than the gradation of the image frame in each gradation, and the image is displayed with the data voltage corresponding to the gradation of the image frame Thereby improving the moving picture response time (MPRT) and displaying an image with an accurate gradation (604 in FIG. 6B).

FIG. 7 illustrates a process of applying overdriving when the gradation of an image frame is the maximum gradation or the lowest gradation in the display apparatus 100 according to the present embodiments.

Referring to FIG. 7, the display apparatus 100 according to the present embodiment checks if an image frame is included in a moving image section (S700). If the image frame is included in a moving image section and the difference in gradation between image frames is large Overdriving is applied.

At this time, the display apparatus 100 according to the present embodiment checks if the average brightness level APL is larger than the threshold value (S710). If the average brightness level APL is larger than the threshold value, All over driving is applied (S720).

If the average brightness level APL is equal to or less than the threshold value, the gradation difference can be recognized at the low gradation level, so that overdriving is applied only at the high gradation level (S730).

If the average luminance level APL is greater than the threshold value, if the gray level of the image frame corresponds to the lowest gray level (S740), the data voltage corresponding to the lowest gray level is outputted in the first period of the image frame to apply overdriving (S760 ). A data voltage corresponding to a gray level higher than the lowest gray level is output in the second section of the image frame to display an image (S770).

If the average luminance level APL is greater than the threshold value, the image frame is checked whether the gradation of the image frame corresponds to the maximum gradation when the gradation of the image frame does not correspond to the lowest gradation or the average luminance level APL is equal to or less than the threshold value (S750 ).

If the gradation of the image frame corresponds to the maximum gradation, the data voltage corresponding to the maximum gradation in the first section of the image frame is output to apply overdriving (S780). In operation S790, a data voltage corresponding to a gray level lower than a maximum gray level is output in the second period of the image frame to display an image.

Therefore, according to the present embodiments, when the gradation of the image frame corresponds to the maximum gradation or the lowest gradation, the image is displayed using the gradation lower than the maximum gradation or the gradation higher than the lowest gradation, To be applied.

Overdriving can be applied in all gradations, thereby improving the video response time (MPRT) and improving the display quality through overdriving when the gradation difference between video frames is large regardless of the gradation of the video frame.

In addition, by changing the overdriving application method in a section adjacent to the maximum gradation or the lowest gradation, the gradation reversal phenomenon caused by displaying an image at a higher gradation than the actual gradation or at a lower gradation can be prevented.

When the gradation of the image frame corresponds to the lowest gradation, overdriving is applied in consideration of the average brightness level (APL), so that the moving picture response time (MPRT) and the display time So that the quality can be improved.

The foregoing description is merely illustrative of the technical idea of the present invention, and various changes and modifications may be made by those skilled in the art without departing from the essential characteristics of the present invention. In addition, the embodiments disclosed in the present invention are not intended to limit the scope of the present invention but to limit the scope of the technical idea of the present invention. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents should be construed as falling within the scope of the present invention.

100: display device 110: display panel
120: gate driver 130: data driver
140: controller

Claims (17)

A display panel in which a plurality of gate lines, a plurality of data lines and a plurality of subpixels are arranged;
A gate driver for outputting a scan signal to the plurality of gate lines; And
And a data driver for outputting a data voltage to the plurality of data lines,
The data driver includes:
When the gradation of the image frame is higher than the predetermined gradation level during over driving, the data voltage corresponding to the maximum gradation in the first period of the image frame is output, and in the second period after the first period, And outputs the data voltage.
The method according to claim 1,
The data driver includes:
If the gray level of the image frame corresponds to the maximum gray level, outputs a data voltage corresponding to the maximum gray level in a first section of the image frame and outputs a data voltage corresponding to a gray level lower than the maximum gray level in a second section of the image frame .
The method according to claim 1,
The data driver includes:
And outputs a data voltage corresponding to the predetermined gray level in a second section of the image frame.
The method according to claim 1,
Wherein a level of a data voltage output from the data driver in a second period of the image frame is different for each gray level of the image frame.
The method according to claim 1,
Wherein the level of the data voltage output from the data driver in the second period of the video frame is gradually decreased in proportion to the grayscale of the video frame and the level of the data voltage is the same.
The method according to claim 1,
The data driver includes:
And outputting a data voltage corresponding to a gray level higher than a gray level of the image frame in a first section of the image frame based on a lookup table if the gray level of the image frame is equal to or less than the predetermined gray level, And outputs a data voltage corresponding to a gray level of the image frame.
The method according to claim 1,
The data driver includes:
And applies the overdriving in the Nth image frame when the difference between the gradation of the (N-1) th image frame and the gradation of the Nth image frame is greater than a predetermined difference.
A display panel in which a plurality of gate lines, a plurality of data lines and a plurality of subpixels are arranged;
A gate driver for outputting a scan signal to the plurality of gate lines; And
And a data driver for outputting a data voltage to the plurality of data lines,
The data driver includes:
When the gradation of the image frame is lower than the predetermined gradation level during over driving, the data voltage corresponding to the lowest gradation level in the first period of the image frame is output, and in the second period after the first period, And outputs a data voltage corresponding to the gray level.
9. The method of claim 8,
The data driver includes:
If the gray level of the image frame corresponds to the lowest gray level, outputs a data voltage corresponding to the lowest gray level in a first section of the image frame and outputs a data voltage corresponding to a gray level higher than the lowest gray level in a second section of the image frame .
9. The method of claim 8,
The data driver includes:
And outputs a data voltage corresponding to the predetermined gray level in a second section of the image frame.
9. The method of claim 8,
Wherein a level of a data voltage output from the data driver in a second period of the image frame is different for each gray level of the image frame.
9. The method of claim 8,
The data driver includes:
And outputting a data voltage corresponding to the lowest gradation in a first section of the image frame and outputting a data voltage corresponding to a gradation higher than a gradation of the image frame in a second section of the image frame if the average luminance level in the image frame is higher than a predetermined level And outputs a data voltage to be applied to the display device.
9. The method of claim 8,
The data driver includes:
And outputs a data voltage corresponding to a gray level of the image frame in a first period and a second period of the image frame when the average luminance level in the image frame is less than a predetermined level.
Determining whether the gradation of the image frame is within a predetermined range when overdriving is applied;
Outputting a data voltage corresponding to a maximum gradation or a lowest gradation in a first section of the image frame if the gradation of the image frame is out of the preset range;
Outputting a data voltage corresponding to a gray level lower than a gray level of the image frame in a second period after the first period if the data voltage corresponding to the maximum gray level is output in the first period; And
And outputting a data voltage corresponding to a gray level higher than the gray level of the image frame in the second period when the data voltage corresponding to the lowest gray level is output in the first period
And a driving method of the display device.
15. The method of claim 14,
If the gray level of the image frame corresponds to the maximum gray level, outputs a data voltage corresponding to the maximum gray level in a first section of the image frame and outputs a data voltage corresponding to a gray level lower than the maximum gray level in a second section of the image frame To the display device.
15. The method of claim 14,
If the gray level of the image frame corresponds to the lowest gray level, outputs a data voltage corresponding to the lowest gray level in a first section of the image frame and outputs a data voltage corresponding to a gray level higher than the lowest gray level in a second section of the image frame To the display device.
17. The method of claim 16,
If the average luminance level of the image frame is higher than a preset level, outputs a data voltage corresponding to the lowest gradation in a first section of the image frame and outputs data corresponding to a gradation higher than the lowest gradation in a second section of the image frame Outputting a voltage,
And outputting a data voltage corresponding to the lowest gray level in a first period and a second period of the image frame when the average luminance level of the image frame is less than the predetermined level.

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