Display device and driving method thereof

Abstract

A display apparatus and a driving method thereof are provided. The display apparatus includes a display panel configured to display an image, a signal controller configured to determine whether an input image signal is a still image signal, and determine a color coordinate using a data value of one frame data of the input image signal, and generate compensated image data by compensating image data of the one frame data based on the color coordinate, and a data driver configured to generate a data signal based on the compensated image data and output the data signal to the display panel through a data line.

Description

[0001] Cross Reference to Related Applications

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2020-0100735, filed on August 11, 2020, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. TECHNICAL FIELD

[0003] The disclosure relates to a display apparatus and a driving method thereof. BACKGROUND

[0004] Research is being conducted to optimize battery consumption of various electronic apparatuses such as smartphones, laptop computers, and tablet personal computers (PCs) that are widely used in our lives.

[0005] Many electronic apparatuses can include a display panel. Battery consumption of the electronic apparatuses can be optimized by minimizing power consumption of the display panel. For example, the display panel can be driven in a low frequency driving mode to reduce its power consumption.

[0006] When the display panel is driven in the low frequency driving mode, a frame period can increase, thereby increasing a leakage current in a pixel, and the leakage current can cause a luminance difference of the pixel between two subsequent frames, thereby causing a flicker phenomenon.

[0007] The above information disclosed in this Background section is only for enhancing understanding of the disclosure, and it can include information that can not be a prior art that is already known in this art to those who have ordinary knowledge. SUMMARY

[0008] The disclosure provides a display apparatus capable of preventing a flicker phenomenon that can occur during low frequency driving and a method of driving the display apparatus.

[0009] The display apparatus can be driven at various driving frequencies and can provide improved display quality.

[0010] According to an embodiment of the disclosure, a display apparatus includes a display panel including a plurality of pixels and configured to display an image, a signal controller configured to determine whether an input image signal is a still image signal, determine a color coordinate using a data value of one frame data of the input image signal, and generate compensated image data by compensating image data of the one frame data based on the color coordinate, and a data driver configured to generate a data signal based on the compensated image data and output the data signal to the display panel through a data line.

[0011] The signal controller can include an image determiner configured to compare at least two frames of data of the input image signal to determine whether the input image signal is a still image signal.

[0012] The image determiner can determine a driving frequency at which one frame of data is displayed based on the determination that the input image signal is a still image signal.

[0013] The image determiner can calculate at least one of a first representative gray value for each pixel, a second representative gray value for each region, and a third representative gray value for the image using gray values of a plurality of pixels in one frame of data based on the determination that the input image signal is a still image signal.

[0014] The signal controller can further include an image compensator configured to generate compensated image data based on the driving frequency, the at least one of the first representative gray value for each pixel, the second representative gray value for the region, and the third representative gray value for the image.

[0015] The image compensator can compensate for image data of one frame of data using compensation data stored in a Look-Up Table (LUT).

[0016] The driving frequency can be lower than 60 Hz.

[0017] The image determiner can receive a Panel Self Refresh (PSR) control signal for controlling a PSR mode in which the display panel displays a still image along with the input image signal, and can determine whether the input image signal is a still image signal based on the PSR control signal.

[0018] Each of the plurality of pixels can include a first transistor connected to a data line and configured to provide a data signal based on a scan signal received through a scan line, a capacitor connected to the second transistor and configured to store a voltage corresponding to the data signal, and a second transistor configured to provide a driving current based on the voltage.

[0019] According to another embodiment of the disclosure, a driving method of a display apparatus includes determining whether an input image signal is a still image signal, determining color coordinates using data values of one frame of data of the input image signal based on the determination that the input image signal is a still image signal, and generating compensated image data by compensating for image data of one frame of data based on the color coordinates, and generating data signals based on the compensated image data and outputting the data signals to a display panel through data lines.

[0020] Determining whether the input image signal is a still image signal can include comparing at least two frames of data of the input image signal to determine whether the input image signal is a still image signal.

[0021] The method can further include determining a driving frequency at which to display one frame of data based on the determination that the input image signal is a still image signal.

[0022] The method can further include calculating at least one of a first representative gray value for each of a plurality of pixels, a second representative gray value for each region, and a third representative gray value for the image using gray values of the plurality of pixels in one frame of data based on the determination that the input image signal is a still image signal.

[0023] The method can further include generating compensation image data based on the driving frequency, the at least one of the first representative gray value for each of the plurality of pixels, the second representative gray value for each region, and the third representative gray value for the image.

[0024] The compensation image data can be generated based on compensation data stored in a look-up table (LUT).

[0025] The driving frequency can be lower than 60 Hz.

[0026] Determining whether the input image signal is a still image signal can include receiving a panel self-refresh (PSR) control signal for controlling a PSR mode in which the display panel displays a still image along with the input image signal, and determining whether the input image signal is a still image signal based on the PSR control signal.

[0027] According to another embodiment of the disclosure, a display apparatus includes a display panel including pixels including light emitting elements configured to emit light according to a driving current corresponding to a data signal applied to a data line, a signal controller configured to generate image data from an input image signal, and a data driver configured to generate the data signal using the image data, wherein the display panel displays an image corresponding to the input image signal at a driving frequency, and wherein voltage values of the data signal corresponding to the same gray value are different from each other based on the driving frequency.

[0028] The signal controller can determine whether the driving frequency is lower than 60 Hz, and compensate one frame of data of the input image signal to generate the image data.

[0029] The signal controller can determine whether the driving frequency is lower than 60 Hz based on the input image signal being a still image signal.

[0030] The display apparatus is capable of providing improved image quality when it is driven at a low frequency.

[0031] According to embodiments, the display device can provide an image having consistent image quality even when the display device is driven at various driving frequencies. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 A block diagram of a display device according to an embodiment is illustrated.

[0033] Figure 2 A circuit diagram illustrating an example of a pixel in a display device according to one embodiment is illustrated. Figure 1

[0034] Figure 3A and Figure 3B A graph illustrating a change in luminance depending on a driving frequency is illustrated.

[0035] Figure 4 A block diagram of a signal controller included in a display device according to one embodiment is illustrated. Figure 1

[0036] Figure 5 A look-up table (LUT) stored in a display device according to an embodiment is illustrated.

[0037] Figure 6 An example of color coordinates is illustrated.

[0038] Figure 7 A flowchart illustrating a driving method of a display device according to an embodiment is illustrated. DETAILED DESCRIPTION

[0039] Hereinafter, the present disclosure will be described more fully with reference to the accompanying drawings, in which various embodiments of the present disclosure will be shown. As those skilled in the art will understand, embodiments described herein can be modified in various different ways without departing from the spirit or scope of the present disclosure.

[0040] For the sake of clarity, portions that are irrelevant to the description can be omitted, and like reference numerals can denote like elements throughout the specification. In the drawings, the thickness of layers, films, panels, regions, etc. can be exaggerated for the sake of description and ease of understanding.

[0041] Further, the sizes and thicknesses of constituent components can be arbitrarily illustrated in the drawings for the sake of better understanding and ease of description, but the present disclosure is not limited to the illustrated sizes and thicknesses. In the drawings, the thickness of layers, films, panels, regions, etc. can be exaggerated for the sake of clarity and ease of description.

[0042] ​​It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, it can be directly on the other element or intervening elements can also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements present. Also, in the description herein, the phrase "on" or "above" means positioned on or below the object, and does not inherently mean positioned on the upper side of the object based on the direction of gravity.

[0043] Also, the word "comprise" and variations such as "comprises" or "comprising" will be understood to imply the inclusion of stated elements, but not the exclusion of any other elements.

[0044] Figure 1 A block diagram of a display device 10 according to an embodiment is shown.

[0045] The display device 10 includes a display panel 100, a scan driver 110, a data driver 120, an emission driver 130, a voltage supplier 140, and a signal controller 150. Also, the display device 10 can be connected to an application processor 160, or the display device 10 can include the application processor 160. Figure 1 Some of the constituent elements shown in FIG. 1 can not be essential for implementing the display device 10, and thus the display device 10 described in the present disclosure can include more or less constituent elements than those listed above.

[0046] The display panel 100 includes a plurality of pixels PX connected with a corresponding scan line of a plurality of scan lines SL1 to SLn, a corresponding data line of a plurality of data lines DL1 to DLm, and a corresponding emission control line of a plurality of emission control lines EM1 to EMn. Each of the plurality of pixels PX emits light corresponding to a data signal transmitted to the corresponding pixel PX via the corresponding data line of the data lines DL1 to DLm, and the display panel 100 can display an image accordingly.

[0047] The scan lines SL1 to SLn can extend substantially in a row direction of the pixels PX to be substantially parallel to each other. The emission control lines EM1 to EMn can also extend substantially in the row direction to be substantially parallel to each other. The data lines DL1 to DLm can extend substantially in a column direction of the pixels PX to be substantially parallel to each other.

[0048] Each of the plurality of pixels PX can receive a high power voltage ELVDD and a low power voltage ELVSS, and an initialization voltage Vint from the voltage supplier 140.

[0049] In this context, the (i-1)th scan line SL(i-1) and the ith scan line SLi, the emission control line EMi, and the supply wire of the initialization voltage Vint of the pixel PX(i,j) can be arranged in the same layer, and the data line DLj and the supply wires of the high power voltage ELVDD and the low power voltage ELVSS of the pixel PX(i,j) can be arranged in the same layer. The (i-1)th scan line SL(i-1) and the ith scan line SLi, the emission control line EMi, the supply wire of the initialization voltage Vint, the data line DLj, and the supply wires of the high power voltage ELVDD and the low power voltage ELVSS can include the same material or different materials, and can be arranged in the same layer or different layers on a substrate (not shown).

[0050] The scan driver 110 is connected to the display panel 100 through the scan lines SL1 to SLn. The scan driver 110 can generate a plurality of scan signals based on the second control signal CONT2 and transmit them to a corresponding scan line among the scan lines SL1 to SLn. The second control signal CONT2 can include an operation control signal of the scan driver 110 generated and transmitted by the signal controller 150.

[0051] The data driver 120 is connected to each pixel PX of the display panel 100 through the data lines DL1 to DLm. The data driver 120 can receive an image data signal (hereinafter, also referred to as image data) DATA and transmit a data signal to a corresponding data line among the data lines DL1 to DLm based on the first control signal CONT1. The first control signal CONT1 can include an operation control signal of the data driver 120 generated and transmitted by the signal controller 150.

[0052] The data driver 120 can select a gray voltage based on the image data signal DATA and transmit it as a data signal to the data lines DL1 to DLm. For example, the data driver 120 can sample and hold the image data signal DATA based on the first control signal CONT1 and can transmit a plurality of data signals to the data lines DL1 to DLm. The data driver 120 can apply a data signal having a predetermined voltage level to the data lines DL1 to DLm in a case where a scan signal having a low level is applied.

[0053] The emission driver 130 can generate a plurality of emission control signals based on a third control signal CONT3. The third control signal CONT3 can include an emission start signal, an emission clock signal that is switched to a low level at different times, a sustain control signal, and / or the like. The emission start signal can generate a first emission control signal for displaying an image of one frame. The emission clock signal included in the third control signal CONT3 can include a synchronization signal for applying the emission control signal to the emission control lines EM1 to EMn. The sustain control signal can control the emission driver 130 to continuously output an emission signal during low-frequency driving.

[0054] The signal controller 150 can receive an external image signal IS and an input control signal that controls the display of an image on the display panel 100. The image signal IS can include luminance information divided by the gray scale value of each pixel PX of the display panel 100.

[0055] The input control signal transmitted to the signal controller 150 can include a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a main clock signal MCLK, a data enable signal DE, a panel self refresh (PSR) control signal PSC, and the like.

[0056] The signal controller 150 can generate a control signal (e.g., CONT1, CONT2, CONT3, CONT4) and an image data signal DATA based on the image signal IS, the horizontal synchronization signal Hsync, the vertical synchronization signal Vsync, the main clock signal MCLK, the data enable signal DE, and the like.

[0057] The signal controller 150 can process the image signal IS according to the operating conditions of the display panel 100 and the data driver 120 based on the input image signal IS and the input control signal. Specifically, the signal controller 150 can generate the image data signal DATA by performing an image processing process such as gamma correction and luminance compensation on the image signal IS.

[0058] The signal controller 150 can transmit the first control signal CONT1 for controlling the operation of the data driver 120 to the data driver 120 together with the image data signal DATA that can have been processed. In addition, the signal controller 150 can transmit the second control signal CONT2 for controlling the operation of the scan driver 110 to the scan driver 110. The signal controller 150 can also transmit the third control signal CONT3 for controlling the operation of the emission driver 130 to the emission driver 130.

[0059] In addition, the signal controller 150 may control driving of the voltage supplier 140. The voltage supplier 140 may supply a high power supply voltage ELVDD and a low power supply voltage ELVSS, and an initialization voltage Vint, for driving each of the plurality of pixels PX of the display panel 100. For example, the signal controller 150 may transmit a fourth control signal CONT4 for controlling the operation of the voltage supplier 140 to the voltage supplier 140. The voltage supplier 140 may be connected to a voltage supply line that may be formed in the display panel 100.

[0060] Figure 2 A diagram illustrating a method according to an embodiment of the present invention is shown. Figure 1 1 is a circuit diagram of an example of a pixel PX in the display device 10.

[0061] The pixel PX arranged in the i-th row and j-th column (also referred to as pixel PX(i,j)) includes a plurality of transistors T1, T2, T3-1, T3-2, T4-1, T4-2, T5, T6 and T7, a capacitor Cst and an organic light emitting diode OLED that are selectively connected to each of the i-th scan line SLi supplied with the i-th scan signal SL[i], the (i-1)th scan line SL(i-1) supplied with the (i-1)th scan signal SL[i-1], the emission control line EMi supplied with the emission control signal EM[i], the supply line of the initialization voltage Vint, the data line DLj supplied with the data signal Data, and the supply lines of the high power voltage ELVDD and the low power voltage ELVSS.

[0062] The gate of the first transistor T1 is connected to the drain of the third transistor T3, the drain of the fourth transistor T4-2, and the first electrode of the capacitor Cst at a first node N1, the source of the first transistor T1 is connected to the drain of the second transistor T2 and the drain of the fifth transistor T5 at a second node N2, and the drain of the first transistor T1 is connected to the source of the third transistor T3-1 and the source of the sixth transistor T6 at a third node N3.

[0063] A gate of the second transistor T2 is connected to the i-th scan line SLi, a source of the second transistor T2 is connected to the data line DLj, and a drain of the second transistor T2 is connected to the source of the first transistor T1 at a second node N2.

[0064] The gate of the third transistor T3 is connected to the i-th scan line SLi, the source of the third transistor T3 is connected to the drain of the first transistor T1 at a third node N3, and the drain of the third transistor T3 is connected to the gate of the first transistor T1 at a first node N1.

[0065] The third transistor T3 can be formed as a dual gate transistor including a third transistor T3-1 and a third transistor T3-2. The gates of the third transistor T3-1 and the third transistor T3-2 are connected to the i-th scan line SLi, the source of the third transistor T3-1 is connected to the drain of the first transistor T1 at the third node N3 and to the anode of the organic light emitting diode OLED via the sixth transistor T6, and the drain of the third transistor T3-2 is connected to the first electrode of the capacitor Cst, the drain of the fourth transistor T4-2, and the gate of the first transistor T1 at the first node N1. Also, the drain of the third transistor T3-1 and the source of the third transistor T3-2 can be connected to each other.

[0066] The gate of the fourth transistor T4 is connected to the (i-1)-th scan line SL(i-1), the source of the fourth transistor T4 is connected to a supply wire of the initialization voltage Vint, and the drain of the fourth transistor T4 is connected to the gate of the first transistor T1 at the first node N1.

[0067] The fourth transistor T4 can be formed as a dual gate transistor including a fourth transistor T4-1 and a fourth transistor T4-2. The gate of the fourth transistor T4-1 is connected to the (i-1)-th scan line SL(i-1), the source of the fourth transistor T4-1 is connected to a supply wire of the initialization voltage Vint, and the drain of the fourth transistor T4-1 is connected to the source of the fourth transistor T4-2.

[0068] The gate of the fourth transistor T4-2 is connected to the (i-1)-th scan line SL(i-1), the source of the fourth transistor T4-2 is connected to the drain of the fourth transistor T4-1, and the drain of the fourth transistor T4-2 is connected to the first electrode of the capacitor Cst, the drain of the third transistor T3-2, and the gate of the first transistor T1 at the first node N1.

[0069] The fourth transistor T4 can be turned on according to a signal received through the (i-1)-th scan line SL(i-1) to transmit the initialization voltage Vint to the gate of the first transistor T1, thereby performing an initialization operation for initializing the voltage of the gate of the first transistor T1.

[0070] The gate of the fifth transistor T5 is connected to the emission control line EMi, the source of the fifth transistor T5 is connected to a supply wire of the high power voltage ELVDD, and the drain of the fifth transistor T5 is connected to the source of the first transistor T1 at the second node N2.

[0071] The gate of the sixth transistor T6 is connected to the emission control line EMi, the source of the sixth transistor T6 is connected to the drain of the first transistor T1 at the third node N3, and the drain of the sixth transistor T6 is connected to the first electrode (e.g., anode) of the organic light emitting diode OLED. The first transistor T1 is connected to the organic light emitting diode OLED through the sixth transistor T6.

[0072] The gate of the seventh transistor T7 is connected to the (i-1)th scan line SL(i-1), the source of the seventh transistor T7 is connected to the first electrode of the organic light emitting diode OLED, and the drain of the seventh transistor T7 is connected to the source of the fourth transistor T4 and the supply line of the initialization voltage Vint.

[0073] The capacitor Cst has a first electrode connected to the gate of the first transistor T1 and the drain of the third transistor T3 at the first node N1, and a second electrode connected to the supply line of the high power voltage ELVDD.

[0074] The organic light emitting diode OLED has a first electrode, a second electrode arranged on the first electrode, and an organic emission layer arranged between the first electrode and the second electrode. The first electrode of the organic light emitting diode OLED is connected to the source of the seventh transistor T7 and the drain of the sixth transistor T6, and the second electrode of the organic light emitting diode OLED is connected to the supply line of the low power voltage ELVSS.

[0075] Figure 3A and Figure 3B A graph illustrating the change in luminance depending on the driving frequency of the display device 10 is shown.

[0076] In particular, Figure 3A A graph illustrating the luminance changed in each frame when the driving frequency of the display device 10 is 60 Hz is shown, and Figure 3B A graph illustrating the luminance changed in each frame when the driving frequency of the display device 10 is 30 Hz is shown.

[0077] As Figure 3B shown in the middle, when the driving frequency is low, i.e., when the image is displayed on the display device 10 at 30 Hz, the luminance decreases by about 8.43% from 420 nits to 384.6 nits. In comparison, as Figure 3A shown in the bottom, when the image is displayed on the display device 10 at 60 Hz, the luminance decreases by 0.71% from 420 nits to 417 nits.

[0078] In the case where the display device 10 is driven at a low drive frequency (e.g., 30 Hz) compared to 60 Hz, a frame period is longer, and thus the drive current flowing through the first transistor T1 can be changed due to the leakage current of the third transistor T3 and the fourth transistor T4, thereby reducing the luminance. Accordingly, among two consecutive frames representing the same luminance, the difference between the luminance at the end of the previous frame and the luminance at the beginning of the next frame can be large. The flicker caused by such a large luminance difference can be visually recognized by the viewer.

[0079] Even when the same luminance is represented, the flicker phenomenon can be recognized differently by the viewer depending on the color. Table 1 shows the flicker recognition index depending on the color, and the larger the flicker recognition index, the more easily the flicker can be recognized by the viewer.

[0080] (Table 1)

[0081]

[0082]

[0083] As shown in Table 1 above, it can be seen that the flicker recognition index is different depending on the luminance and the color, and the flicker recognition characteristic is generally low in the red and blue colors. The display device 10 can reduce the recognition of flicker when driven at a low drive frequency by compensating the image data signal DATA with a color having a low flicker recognition characteristic depending on the luminance by considering at least one of the representative gray value and color for each region in the image data of one frame (i.e., one frame data) and the representative gray value and color of the entire image.

[0084] Figure 4 A block diagram of the signal controller 150 included in the display device 10 according to one embodiment is shown. Figure 1 A block diagram of the signal controller 150 included in the display device 10 according to one embodiment is shown.

[0085] The signal controller 150 of the display device 10 includes an image determiner 151, an image compensator 153, and a frame memory 155.

[0086] The image determiner 151 receives an image signal IS. The image determiner 151 can determine whether the input image signal IS represents a still image or a moving picture (or video). In an embodiment, the image determiner 151 can compare data of at least two frames of the input image signal IS (i.e., at least two frames of data) to determine whether the input image signal IS represents a still image signal or a moving picture signal. The image determiner 151 can store the at least two frames of data of the image signal IS in the frame memory 155 and compare them to determine whether the image signal IS represents a still image or a moving picture. In this context, the at least two frames of data can be temporally adjacent (or continuous) to each other. Depending on the embodiment, the image determiner 151 can determine that the image signal IS represents a still image when two adjacent frames of data are continuously identical or substantially continuously identical for a predetermined frame (time) or longer.

[0087] For example, image detector 151 may compare at least two temporally adjacent frames of frame data of the image signal IS. Specifically, image detector 151 may compare a first data value included in the first frame data (e.g., the first data value of a specific region) with a second data value included in the second frame data (e.g., the second data value of the specific region). If the difference (or the amount of the difference) between the first and second data values ​​is less than or equal to a predetermined reference value, image detector 151 may determine that the input image signal IS is a still image signal. If the difference exceeds the predetermined reference value, image detector 151 may determine that the input image signal IS is a moving picture signal.

[0088] As another example, image determiner 151 may compare data values ​​of certain regions within at least two temporally adjacent frames of the image signal IS. For example, image determiner 151 may compare data values ​​of one or more corresponding regions within the first and second frames. Specifically, image determiner 151 may compare a first data value corresponding to a specific region within the first frame with a second data value corresponding to a specific region within the second frame. If the difference (or the amount of the difference) between the first and second data values ​​is less than or equal to a predetermined reference value, image determiner 151 may determine that the specific region of the input image signal IS displays a still image. If the difference exceeds the predetermined reference value, image determiner 151 may determine that the specific region of the input image signal IS displays a moving picture signal.

[0089] According to one embodiment, in response to the PSR control signal PSC, the image determiner 151 can determine a PSR mode section start based on a PSR start signal included in the PSR control signal PSC, and can determine that the received input image signal IS is a still image signal. When the PSR start signal is received, the image determiner 151 can store frame data of the received input image signal IS in the frame memory 155.

[0090] When the image signal IS or a region thereof is determined to display a still image, the image determiner 151 can determine a driving frequency for displaying an image of one frame. For example, the image determiner 151 can determine the driving frequency based on a period of the input data enable signal DE. The image determiner 151 can also consider a period in which a still image is maintained (e.g., a period from a time point at which a still image starts to a time point at which a still image transition occurs) to determine the driving frequency. The image determiner 151 can determine the driving frequency so that an image of one frame is displayed at a lower driving frequency when the period in which a still image is maintained is longer. In this case, the driving frequency (also referred to as a low driving frequency) can be 60 Hz or less, for example, 30 Hz, 20 Hz, 15 Hz, or 10 Hz.

[0091] The image determiner 151 can calculate at least one of a representative gray value of each pixel of image data of one frame, a representative gray value of each region of image data of one frame, and a representative gray value of image data of one frame, using gray values of pixels in image data of one frame of the image signal IS.

[0092] For example, the image determiner 151 can calculate a representative gray value of one pixel as follows.

[0093] (Equation 1)

[0094] Gray px = a * R + b * G + c * B

[0095] In this context, R, G, and B can indicate gray values of red, green, and blue (R, G, and B) of a corresponding pixel, respectively, and a, b, and c are constants, and a color having a higher flicker recognition index can have a greater representative gray value. In Equation 1, although values of red R, green G, and blue B are described as examples, values of cyan, magenta, yellow, and black (CMYK) can be used. It is to be understood that the present disclosure is not limited to these examples.

[0096] The image determiner 151 can divide image data into a plurality of regions, and can calculate an average representative gray value of pixels included in each of the plurality of regions. For example, the image determiner 151 can calculate an average representative gray value of all pixels included in the image data.

[0097] The image compensator 153 can compensate for the image data received from the image determiner 151 to display color coordinates corresponding to the determined driving frequency and representative gray value. For example, the image compensator 153 can include a predetermined compensation look-up table (LUT) 1530 based on the physical characteristics of the display panel 100. The image compensator 153 can compensate for the image data by referring to the compensation LUT 1530. The compensation LUT 1530 includes a plurality of LUTs 1531, 1533, …, and 1535 corresponding to representative gray values and driving frequencies. Even if the image data has the same representative gray value, the image compensator 153 can compensate for the image data by reading different LUTs based on the driving frequency.

[0098] Figure 5 A look-up table (LUT) stored in the display apparatus 10 according to an embodiment is illustrated, and Figure 6 An example of color coordinates is illustrated.

[0099] Figure 4 The image compensator 153 of FIG. 1 can read a LUT according to color coordinates corresponding to a representative gray value of a pixel, i.e., optimal flicker color coordinates (simply, optimal color coordinates), and can compensate for a gray value of image data accordingly. For example, as illustrated in FIG. 2, Figure 6 in the case where color coordinates of the display apparatus 10 are 0.305 and 0.321 (①) and the representative gray value is 223, the color coordinates can be moved to 0.299 and 0.312 (⑤) with reference to the LUT of FIG. 1. To this end, the image compensator 153 can compensate for a gray value of image data using a compensation value stored in the LUT. The compensation value depending on color coordinates can be different according to the physical characteristics of the display panel 100. Also, one LUT stores one or more compensation values corresponding to a plurality of gray values. Figure 5

[0100] Each LUT can have a compensation value corresponding to a representative gray value and a driving frequency. In Figure 5 FIG. 1, when the representative gray value is 191 to 255, the image compensator 153 applies a compensation value stored in 1533 in LUT #1 (LUT #1), but when the driving frequency is different, even if they have the same representative gray value, the image compensator 153 can apply a compensation value stored in another LUT. Figure 4

[0101] Referring back to Figure 4 , the image compensator 153 can output the compensated image data DATA to the data driver 120.

[0102] In Figure 4 ​​In this case, the image determiner 151 and the frame memory 155 are shown as included in the signal controller 150, but the image determiner 151 and the frame memory 155 can be included in a different element, such as the application processor 160. In this case, the steps S100, S110, S120, and S130 in FIG. 1 will be described below. Figure 7 The steps S100, S110, S120, and S130 in FIG. 1 can be performed by the application processor 160.

[0103] Figure 7 is a flowchart illustrating a driving method of the display apparatus 10 according to an embodiment.

[0104] Figure 4 The image determiner 151 of FIG. 1 receives the image signal IS (S100).

[0105] Next, the image determiner 151 determines whether the input image signal IS displays a still image or a moving picture (S110).

[0106] If the image determiner 151 determines that the image signal IS or a region thereof displays a still image, the image determiner 151 determines a driving frequency for displaying an image of one frame (S120). If the image determiner 151 determines that the image signal IS or a region thereof displays a moving picture, the image compensator 153 can output the image data DATA to the data driver 120 without compensating the image data DATA (S170). The image determiner 151 can compare data of at least two frames of the input image signal IS to determine whether the input image signal IS is a still image signal or a moving picture signal. Alternatively, the image determiner 151 can receive the PSR control signal PSC and determine a PSR mode section start based on a PSR start signal included in the PSR control signal PSC, and can determine that the received input image signal IS is a still image signal.

[0107] Next, the image determiner 151 can use the gray scale values of the pixels in the image data of one frame of the image signal IS and calculate at least one of a representative gray scale value for each pixel, a representative gray scale value for each region, and a representative gray scale value for the entire image (S130). The image determiner 151 can calculate the representative gray scale value using the gray scale values of red R, green G, blue B of the pixels and weight values.

[0108] The image compensator 153 can determine color coordinates corresponding to the driving frequency determined in S120 and the representative gray scale value calculated in S130 (S140).

[0109] The image compensator 153 can look up the compensation LUT 1530 based on the corresponding color coordinates (S150).

[0110] The image compensator 153 can compensate the image data using the compensation values stored in the compensation LUT 1530 (S160).

[0111] The image compensator 153 can output the compensated image data DATA to the data driver 120 (S170).

[0112] As described above, the display apparatus 10 can reduce the recognition of flicker when driven at a low driving frequency by compensating the image data DATA with a color having a low flicker recognition characteristic based on brightness by considering at least one of a representative gray value and color for each region in the image data of one frame and a representative gray value and color of the entire image.

[0113] While the disclosure has been described in connection with certain embodiments thereof, it will be understood that the disclosure is not limited to the embodiments disclosed but is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the disclosure, including the appended claims.

Claims

1. A display device comprising: a display panel comprising a plurality of pixels and configured to display an image; a signal controller configured to determine whether an input image signal is a still image signal, determine color coordinates using data values ​​of one frame of data of the input image signal, and generate compensated image data by compensating image data of the one frame of data based on the color coordinates; as well as a data driver configured to generate a data signal based on the compensated image data and output the data signal to the display panel through a data line, The signal controller includes an image determiner configured to compare at least two adjacent frame data of the input image signal to determine whether the input image signal is the still image signal. wherein the image determiner determines a driving frequency for displaying the one frame of data based on a determination that the input image signal is the still image signal, wherein the image determiner calculates at least one of a first representative grayscale value for each of the plurality of pixels, a second representative grayscale value for each region, and a third representative grayscale value of the image using grayscale values ​​of the plurality of pixels in the one frame of data based on a determination that the input image signal is the still image signal, and Wherein, the signal controller also includes an image compensator, which is configured to generate the compensated image data based on the driving frequency, the first representative grayscale value for each pixel of the multiple pixels, the second representative grayscale value for each area and at least one of the third representative grayscale value of the image.

2. The display device according to claim 1, wherein The image compensator compensates the image data of the one frame data using compensation data stored in a lookup table.

3. The display device according to claim 1, wherein The driving frequency is lower than 60 Hz.

4. The display device according to claim 1, wherein The image determiner receives a panel self-refresh control signal for controlling a panel self-refresh mode in which the display panel displays a still image together with the input image signal, and determines whether the input image signal is the still image signal based on the panel self-refresh control signal.

5. The display device according to claim 1, wherein Each of the plurality of pixels comprises: a first transistor connected to the data line and providing the data signal based on a scan signal received through a scan line; a capacitor connected to the second transistor and configured to store a voltage corresponding to the data signal; and The second transistor provides a driving current based on the voltage.

6. A method for driving a display device, comprising: determining whether the input image signal is a still image signal; calculating, based on a determination that the input image signal is the still image signal, representative grayscale values ​​including at least one of a first representative grayscale value of each pixel of the plurality of pixels, a second representative grayscale value of each region, and a third representative grayscale value of the image using grayscale values ​​of a plurality of pixels of one frame of data of the input image signal, and determining color coordinates using the representative grayscale values; determining a driving frequency for displaying the one frame of data based on a determination that the input image signal is the still image signal, and generating compensated image data by compensating image data of the one frame of data based on the driving frequency and the color coordinates; as well as A data signal is generated based on the compensated image data, and the data signal is output to a display panel through a data line.

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