Display device and method of operating a display device

Abstract

A display device and a method of operating the display device are provided. The display device includes: a display panel including a plurality of pixels; a sensing data memory configured to store sensing data of threshold voltages of driving transistors of the plurality of pixels; a controller configured to determine a total threshold voltage offset of the driving transistors of the plurality of pixels based on the sensing data, determine total luminance data based on input image data, determine a frame stress based on the total luminance data and the total threshold voltage offset, determine a target compensation voltage level based on the frame stress, and generate compensated image data by compensating the input image data based on the target compensation voltage level; and a data driver configured to provide a data voltage to the plurality of pixels based on the compensated image data.

Description

Technical Field

[0001] Aspects of some example embodiments of the inventive concept relate to a display device. Background Art

[0002] Even when a plurality of pixels included in a display device such as an organic light emitting diode (OLED) display device are manufactured as part of the same manufacturing process, driving transistors of the plurality of pixels may have different driving characteristics due to variations in the manufacturing process and the like. Accordingly, the plurality of pixels may emit light having different brightnesses. In addition, as the OLED display device operates over time, the plurality of pixels may deteriorate, and the driving characteristics of the driving transistors may deteriorate over time. To compensate for non-uniformity in brightness between pixels and deterioration of pixels, the OLED display device may perform a sensing operation of sensing driving characteristics (e.g., threshold voltage and / or mobility) of driving transistors of the plurality of pixels. The OLED display device may display an image having relatively uniform brightness by compensating image data based on sensing data generated by the sensing operation.

[0003] The above information disclosed in this Background Art section is only for enhancing understanding of the background art, and thus, the information discussed in this Background Art section does not necessarily constitute the prior art. Summary of the Invention

[0004] Aspects of some example embodiments of the inventive concept relate to a display device, for example, to a display device that compensates image data based on sensing data and a method of operating the display device.

[0005] Aspects of some example embodiments include a display device that may be capable of improving deterioration characteristics and reducing power consumption.

[0006] Aspects of some example embodiments include a method of operating a display device that may be capable of improving deterioration characteristics and reducing power consumption.

[0007] According to some example embodiments, a display device includes: a display panel including a plurality of pixels; a sensing data memory configured to store sensing data of threshold voltages of driving transistors of the plurality of pixels; a controller configured to determine a total threshold voltage offset of the driving transistors of the plurality of pixels based on the sensing data, determine total luminance data based on input image data, determine a frame stress based on the total luminance data and the total threshold voltage offset, determine a target compensation voltage level based on the frame stress, and generate compensated image data by compensating the input image data based on the target compensation voltage level; and a data driver configured to provide data voltages to the plurality of pixels based on the compensated image data.

[0008] According to some example embodiments, the controller may determine a target compensation voltage level such that the target compensation voltage level increases as the frame stress increases.

[0009] According to some example embodiments, the controller may compare the frame stress with a reference stress, may determine the target compensation voltage level as a default compensation voltage level when the frame stress is less than or equal to the reference stress, and may increase the target compensation voltage level in linear proportion to the frame stress as the frame stress increases when the frame stress is greater than the reference stress.

[0010] According to some example embodiments, the controller may compare the frame stress with a reference stress, may determine the target compensation voltage level as a default compensation voltage level when the frame stress is less than or equal to the reference stress, and may increase the target compensation voltage level by using an Nth order equation of the frame stress as the frame stress increases when the frame stress is greater than the reference stress, where N is an integer greater than 1.

[0011] According to some example embodiments, the controller may generate a plurality of pixel compensation data based on a difference between the target compensation voltage level and a plurality of threshold voltage levels corresponding to a plurality of threshold voltage data included in the sensed data, and may generate compensated image data by adding the plurality of pixel compensation data to the input image data.

[0012] According to some example embodiments, each of the plurality of pixels may include: a switching transistor configured to transmit a data voltage of a data line in response to a scan signal; a storage capacitor configured to store the data voltage transmitted by the switching transistor; a driving transistor configured to generate a driving current based on the data voltage stored in the storage capacitor; an organic light emitting diode configured to emit light based on the driving current generated by the driving transistor; and a sensing transistor configured to connect a node between the driving transistor and the organic light emitting diode to a sensing line in response to a sensing signal.

[0013] According to some example embodiments, the display device may further include a sensing circuit coupled to a plurality of sensing lines. During a sensing period, the data driver may provide a reference voltage to the plurality of pixels through the plurality of data lines. During the sensing period, the sensing circuit may receive a plurality of sensing voltages from the plurality of pixels through the plurality of sensing lines, and may generate sensed data corresponding to a difference between the reference voltage and the plurality of sensing voltages. The controller may receive the sensed data from the sensing circuit, and may write the sensed data into a sensed data memory.

[0014] According to some example embodiments, the controller may include: a threshold voltage offset calculation block configured to calculate current total threshold voltage data by summing a plurality of threshold voltage data included in sensed data, and to calculate a total threshold voltage offset amount by subtracting initial total threshold voltage data before degradation of the plurality of pixels from the current total threshold voltage data; a frame stress calculation block configured to calculate total luminance data by summing a plurality of pixel data included in input image data, and to calculate frame stress by summing the total threshold voltage offset amount and the total luminance data; a compensation target determination block configured to determine a target compensation voltage level based on the frame stress; and a data compensation block configured to generate a plurality of pixel compensation data based on a difference between the target compensation voltage level and a plurality of threshold voltage levels corresponding to the plurality of threshold voltage data, and to generate compensated image data by adding the plurality of pixel compensation data to the input image data.

[0015] According to some example embodiments, the compensation target determination block may store M frame stresses in M frame periods (where M is an integer greater than 0), may calculate an average value of the M frame stresses, and may determine a target compensation voltage level based on the average value of the M frame stresses.

[0016] According to some example embodiments, in a case where the frame stress is changed from a first frame stress to a second frame stress, the compensation target determination block may gradually change the target compensation voltage level from a first target compensation voltage level corresponding to the first frame stress to a second target compensation voltage level corresponding to the second frame stress within a transition time corresponding to a plurality of frame periods.

[0017] According to some example embodiments, the compensation target determination block may receive a dimming signal representing a dimming level, and may determine a target compensation voltage level based on the frame stress and the dimming signal such that the target compensation voltage level increases as the frame stress increases and the target compensation voltage level increases as the dimming level increases.

[0018] According to some example embodiments, the plurality of pixels include red pixels, green pixels, and blue pixels. A controller may determine a total threshold voltage offset amount of the red pixels, a total threshold voltage offset amount of the green pixels, and a total threshold voltage offset amount of the blue pixels as a total threshold voltage offset amount, may determine a total luminance data for the red pixels, a total luminance data for the green pixels, and a total luminance data for the blue pixels as a total luminance data, may determine a red frame stress based on the total luminance data of the red pixels and the total threshold voltage offset amount of the red pixels, a green frame stress based on the total luminance data of the green pixels and the total threshold voltage offset amount of the green pixels, and a blue frame stress based on the total luminance data of the blue pixels and the total threshold voltage offset amount of the blue pixels as a frame stress, may determine a red target compensation voltage level corresponding to the red frame stress, a green target compensation voltage level corresponding to the green frame stress, and a blue target compensation voltage level corresponding to the blue frame stress as a target compensation voltage level, and may generate compensated image data by compensating input image data based on the red target compensation voltage level, the green target compensation voltage level, and the blue target compensation voltage level.

[0019] According to some example embodiments, a display panel may be divided into a plurality of pixel blocks. A controller may determine a plurality of block target compensation voltage levels for the plurality of pixel blocks as a target compensation voltage level, and may generate compensated image data by compensating input image data based on the plurality of block target compensation voltage levels.

[0020] According to some example embodiments, in a case where the input image data is black image data representing a 0 gray level, the controller may generate compensated image data representing a negative gray level based on a target compensation voltage level that is a positive voltage level, and a data driver may provide a data voltage corresponding to the compensated image data representing the negative gray level to the plurality of pixels, such that a threshold voltage of a driving transistor is shifted in a negative direction.

[0021] According to some example embodiments, in a method of operating a display device including a plurality of pixels, the method includes: storing sensed data of threshold voltages of driving transistors of the plurality of pixels; determining a total threshold voltage offset amount of the driving transistors of the plurality of pixels based on the sensed data; determining total luminance data based on the input image data; determining a frame stress based on the total luminance data and the total threshold voltage offset amount; determining a target compensation voltage level based on the frame stress; generating compensated image data by compensating the input image data based on the target compensation voltage level; and providing a data voltage to the plurality of pixels based on the compensated image data.

[0022] According to some example embodiments, in order to determine the target compensation voltage level, the target compensation voltage level may be increased as the frame stress increases.

[0023] According to some example embodiments, to determine a target compensation voltage level, a frame stress may be compared with a reference stress, the target compensation voltage level may be determined as a default compensation voltage level when the frame stress is less than or equal to the reference stress, and the target compensation voltage level may increase linearly in proportion to the frame stress as the frame stress increases when the frame stress is greater than the reference stress.

[0024] According to some example embodiments, to determine a target compensation voltage level, M frame stresses in M frame periods (where M is an integer greater than 0) may be stored, an average value of the M frame stresses may be calculated, and the target compensation voltage level may be determined based on the average value of the M frame stresses.

[0025] According to some example embodiments, to determine a target compensation voltage level, in a case where the frame stress is changed from a first frame stress to a second frame stress, the target compensation voltage level may be gradually changed from a first target compensation voltage level corresponding to the first frame stress to a second target compensation voltage level corresponding to the second frame stress within a transition time corresponding to a plurality of frame periods.

[0026] According to some example embodiments, to determine a target compensation voltage level, a dimming signal representing a dimming level may be received, and the target compensation voltage level may be determined based on the frame stress and the dimming signal. The target compensation voltage level may increase as the frame stress increases, and the target compensation voltage level may increase as the dimming level increases.

[0027] As described above, in a display device and a method of operating the display device according to some example embodiments, a total threshold voltage offset amount of driving transistors of a plurality of pixels may be determined based on sensing data, total luminance data may be calculated based on input image data, a frame stress may be determined based on the total luminance data and the total threshold voltage offset amount, a target compensation voltage level may be determined based on the frame stress, and compensated image data may be generated by compensating the input image data based on the target compensation voltage level. Accordingly, power consumption of the display device may be reduced, degradation characteristics may be improved, and a micro dimming mode may be implemented. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Exemplary non-limiting example embodiments will be understood more clearly through the following detailed description in conjunction with the drawings.

[0029] Figure 1 is a block diagram showing a display device according to some example embodiments.

[0030] Figure 2 is a circuit diagram showing an example of a pixel included in a display device according to some example embodiments.

[0031] Figure 3is a block diagram showing a controller included in a display device according to some example embodiments.

[0032] Figure 4 is a flowchart showing a method of operating a display device according to some example embodiments.

[0033] Figure 5 is a diagram showing an example of frame stress according to some example embodiments.

[0034] Figure 6 is a diagram showing an example of a target compensation voltage level according to frame stress according to some example embodiments.

[0035] Figure 7 is a diagram showing another example of a target compensation voltage level according to frame stress according to some example embodiments.

[0036] Figure 8A is a diagram showing an example of a data voltage corresponding to compensated image data in a case where a target compensation voltage level is determined to be a default compensation voltage level.

[0037] Figure 8B is a diagram showing an example of a data voltage corresponding to compensated image data in a case where a target compensation voltage level is determined to be a voltage level higher than a default compensation voltage level.

[0038] Figure 9 is a flowchart showing a method of operating a display device according to some example embodiments.

[0039] Figure 10 is a diagram showing an example of determining a target compensation voltage level based on an average value of M frame stresses.

[0040] Figure 11 is a flowchart showing a method of operating a display device according to some example embodiments.

[0041] Figure 12 is a diagram showing an example in which a target compensation voltage level is gradually changed during a transition time corresponding to a plurality of frame periods.

[0042] Figure 13 is a block diagram showing a controller included in a display device according to some example embodiments.

[0043] Figure 14 is a flowchart showing a method of operating a display device according to some example embodiments.

[0044] Figure 15 is a block diagram showing a controller included in a display device according to some example embodiments.

[0045] Figure 16It is a flowchart showing a method of operating a display device according to some example embodiments.

[0046] Figure 17 It is a block diagram showing an electronic device including a display device according to some example embodiments. Detailed Description

[0047] Hereinafter, embodiments of the inventive concept will be explained in more detail with reference to the accompanying drawings.

[0048] Figure 1 It is a block diagram showing a display device according to some example embodiments, Figure 2 It is a circuit diagram showing an example of a pixel included in a display device according to some example embodiments, Figure 3 It is a block diagram showing a controller included in a display device according to some example embodiments.

[0049] Referring to Figure 1 , a display device 100 according to some example embodiments may include a display panel 110, a scan driver 120, a data driver 130, a sensing circuit 140, a sensing data memory 150, and a controller 160.

[0050] The display panel 110 may include a plurality of data lines DL, a plurality of sensing lines SL, and a plurality of pixels PX coupled to the plurality of data lines DL and the plurality of sensing lines SL. According to some example embodiments, the number of the plurality of sensing lines SL may be substantially the same as the number of the plurality of data lines DL. According to some example embodiments, the number of the plurality of sensing lines SL may be different from the number of the plurality of data lines DL. For example, the display panel 110 may include one sensing line SL for every three data lines DL. According to some example embodiments, each pixel PX may include an organic light-emitting diode (OLED), and the display panel 110 may be an OLED panel.

[0051] For example, as shown in Figure 2 , each pixel PX may include a switching transistor T2, a storage capacitor CST, a driving transistor T1, an OLED EL, and a sensing transistor T3. The switching transistor T2 transmits a data voltage DV (or a reference voltage VREF) transmitted through the data line DL in response to a scan signal SS. The storage capacitor CST stores the data voltage DV transmitted by the switching transistor T2. The driving transistor T1 generates a driving current based on the data voltage DV stored in the storage capacitor CST. The OLED EL emits light in response to the driving current flowing from the line of the first power supply voltage ELVDD to the line of the second power supply voltage ELVSS. The sensing transistor T3 connects a node NO between the driving transistor T1 and the OLED EL to the sensing line SL in response to a sensing signal SSEN.

[0052] According to some example embodiments, as Figure 2 shown in Figure 2 , the driving transistor T1, the switching transistor T2, and the sensing transistor T3 may be implemented using NMOS transistors, but the embodiments are not limited to NMOS transistors. However, the configuration of the pixel PX according to some example embodiments may not be limited to Figure 2 the example of Figure 2 . In addition, according to some example embodiments, the display panel 110 may be an inorganic light-emitting diode display panel, a quantum dot light-emitting diode display panel, a liquid crystal display (LCD) panel, or any other suitable display panel.

[0053] The scan driver 120 may provide the scan signal SS and / or the sense signal SSEN to the plurality of pixels PX based on the scan control signal SCTRL received from the controller 160. According to some example embodiments, the scan control signal SCTRL may include, but is not limited to, a scan start signal and a scan clock signal. According to some example embodiments, the scan driver 120 may be integrated or formed in the peripheral portion of the display panel 110. According to some example embodiments, the scan driver 120 may be implemented using one or more integrated circuits.

[0054] The data driver 130 may provide the data voltage DV to the plurality of pixels PX through a plurality of data lines DL based on the data control signal DCTRL and the compensated image data CDAT received from the controller 160. According to some example embodiments, the data control signal DCTRL may include, but is not limited to, an output data enable signal, a horizontal start signal, and a load signal. According to some example embodiments, the data driver 130 and the sensing circuit 140 may be implemented using at least one single integrated circuit. The single integrated circuit including the data driver 130 and the sensing circuit 140 may be referred to as a readout-source driver integrated circuit (RSIC).

[0055] According to some example embodiments, the data driver 130 and the controller 160 may be implemented using at least one single integrated circuit. The single integrated circuit including the data driver 130 and the controller 160 may be referred to as a timing controller embedded data driver (TED). According to some example embodiments, the data driver 130, the sensing circuit 140, and the controller 160 may be implemented using separate integrated circuits.

[0056] The sensing circuit 140 may be coupled to a plurality of sensing lines SL of the display panel 110, and may sense the driving characteristics (e.g., threshold voltage VTH and / or mobility) of the driving transistors T1 of the plurality of pixels PX through the plurality of sensing lines SL. For example, asFigure 1 and Figure 2 As shown in Figure 2 , during the sensing period, the data driver 130 may provide a reference voltage VREF to a plurality of pixels PX through a plurality of data lines DL. A node NO between a driving transistor T1 and an OLED EL in the plurality of pixels PX may have a voltage VREF - VTH obtained by subtracting the threshold voltage VTH of the driving transistor T1 from the reference voltage VREF. The sensing circuit 140 may receive a plurality of sensing voltages VSEN from the plurality of pixels PX through a plurality of sensing lines SL or a voltage VREF - VTH obtained by subtracting the threshold voltage VTH from the reference voltage VREF.

[0057] During the sensing period, the second power supply voltage ELVSS may be adjusted to have a voltage level substantially the same as that of the first power supply voltage ELVDD. Therefore, the OLED EL may not emit light. In addition, the sensing circuit 140 may generate sensing data SD, and the sensing data SD corresponds to the difference between the reference voltage VREF and the plurality of sensing voltages VSEN or corresponds to the threshold voltage VTH of the driving transistors T1 of the plurality of pixels PX.

[0058] According to some example embodiments, the sensing circuit 140 may include an analog-to-digital converter (ADC) for converting the threshold voltage VTH into sensing data SD, but the embodiment is not limited to the analog-to-digital converter (ADC). The controller 160 may receive the sensing data SD from the sensing circuit 140 and may write the sensing data SD into the sensing data memory 150. According to some example embodiments, the sensing circuit 140 may generate the sensing data SD when the display device 100 is manufactured (or before the plurality of pixels PX deteriorate), generate the sensing data SD when the display device 100 is powered on or off, and / or generate the sensing data SD periodically during the operation of the display device 100.

[0059] The sensing data memory 150 may store sensing data SD representing the driving characteristics (e.g., threshold voltage VTH and / or mobility) of the driving transistors T1 of the plurality of pixels PX. According to some example embodiments, when the display device 100 is manufactured or before the plurality of pixels PX deteriorate, the sensing data SD including a plurality of threshold voltage data representing the threshold voltage VTH of the driving transistors T1 of the plurality of pixels PX may be stored in the sensing data memory 150. The total threshold voltage data calculated by summing or adding the plurality of threshold voltage data may be further stored in the sensing data memory 150 as the initial total threshold voltage data before the plurality of pixels PX deteriorate. In addition, after the driving time of the display device 100 increases or after the plurality of pixels PX deteriorate, the sensing data SD in the sensing data memory 150 may be updated periodically or aperiodically.

[0060] A controller 160 (e.g., a timing controller (TCON)) may receive input image data IDAT and a control signal CTRL from an external host processor (e.g., a graphics processing unit (GPU), an application processor (AP), or a graphics card). According to some example embodiments, the input image data IDAT may be RGB image data including red image data, green image data, and blue image data. According to some example embodiments, the control signal CTRL may include a vertical synchronization signal, a horizontal synchronization signal, an input data enable signal, a main clock signal, etc., but the embodiments are not limited to the vertical synchronization signal, the horizontal synchronization signal, the input data enable signal, the main clock signal, etc. The controller 160 may control the operation of the scan driver 120 by providing a scan control signal SCTRL to the scan driver 120, and may control the operation of the data driver 130 by providing compensation image data CDAT and a data control signal DCTRL to the data driver 130.

[0061] As the driving time of the display device 100 increases, multiple pixels PX deteriorate. The sensing circuit 140 may generate sensing data SD by sensing the threshold voltage VTH of the driving transistors T1 of multiple deteriorated pixels PX, and the sensing data memory 150 may store the sensing data SD. The controller 160 may generate compensation image data CDAT by compensating the input image data IDAT based on the sensing data SD stored in the sensing data memory 150, and the data driver 130 may provide a data voltage DV to the multiple pixels PX based on the compensation image data CDAT.

[0062] Since the threshold voltage VTH of the driving transistors T1 of multiple deteriorated pixels PX is reflected in the data voltage DV generated based on the compensation image data CDAT, the multiple pixels PX may emit light with uniform brightness based on the data voltage DV generated based on the compensation image data CDAT. However, in this case, the threshold voltage VTH is added to each data voltage DV, the power consumption of the display device 100 increases, and the deterioration of the multiple pixels PX or the deterioration of the driving transistors T1 accelerates.

[0063] To reduce the power consumption of the display device 100 and to reduce or recover the deterioration of the multiple pixels PX, the controller 160 of the display device 100 according to some example embodiments may determine a total threshold voltage offset of the driving transistors T1 of the multiple pixels PX based on the sensing data SD, may determine total luminance data based on the input image data IDAT, may determine a frame stress based on the total luminance data and the total threshold voltage offset, may determine a target compensation voltage level based on the frame stress, and may generate compensation image data CDAT by compensating the input image data IDAT based on the target compensation voltage level.

[0064] For example, the controller 160 may generate a plurality of pixel compensation data based on the difference between the target compensation voltage level and a plurality of threshold voltage levels corresponding to a plurality of threshold voltage data included in the sensed data SD, and may generate compensated image data CDAT by adding the plurality of pixel compensation data to the input image data IDAT. The data driver 130 may supply a data voltage DV to the plurality of pixels PX based on the compensated image data CDAT.

[0065] According to some example embodiments, the controller 160 may calculate a frame stress by summing (or adding) the total luminance data and the total threshold voltage offset, and may determine a target compensation voltage level such that the target compensation voltage level increases as the frame stress or the sum of the total luminance data and the total threshold voltage offset increases. Accordingly, the target compensation voltage level may be determined according to the frame stress, which is calculated by summing the total luminance data corresponding to the total luminance of the image represented by the input image data IDAT and the total threshold voltage offset corresponding to the degradation degree of the plurality of pixels PX or the degradation degree of the driving transistor T1, and the data voltage DV may be generated based on the target compensation voltage level. Accordingly, in a case where the total luminance of the image represented by the input image data IDAT is too high, the data voltage DV may be reduced by adjusting the target compensation voltage level, and thus, the power consumption of the display device 100 may be reduced. In addition, in a case where the plurality of pixels PX or the driving transistor T1 is excessively degraded, the data voltage DV may be reduced by adjusting the target compensation voltage level, and thus, the degradation process of the driving transistor T1 may be delayed.

[0066] To perform these operations, as Figure 3 shown, the controller 160 of the display device 100 according to some example embodiments may include a threshold voltage offset calculation block 310, a frame stress calculation block 320, a compensation target determination block 350, and a data compensation block 360.

[0067] The threshold voltage shift calculation block 310 may determine a total threshold voltage shift amount TVTHSA of the driving transistors T1 of a plurality of pixels PX based on the sensed data SD. According to some example embodiments, the threshold voltage shift calculation block 310 may calculate a current total threshold voltage data by summing a plurality of threshold voltage data included in the sensed data SD, and may calculate the total threshold voltage shift amount TVTHSA by subtracting an initial total threshold voltage data before degradation of the plurality of pixels PX stored in the sensed data memory 150 from the current total threshold voltage data. In addition, according to some example embodiments, the threshold voltage shift calculation block 310 may reflect the input image data IDAT representing the current input gray level and / or the current driving conditions such as the current temperature when calculating the current total threshold voltage data and / or the total threshold voltage shift amount TVTHSA.

[0068] The frame stress calculation block 320 may determine a total luminance data TLD based on the input image data IDAT, and may determine a frame stress FS based on the total luminance data TLD and the total threshold voltage shift amount TVTHSA. According to some example embodiments, as Figure 3 shown, the frame stress calculation block 320 may include a total luminance calculator 330 and an adder 340. The total luminance calculator 330 may calculate the total luminance data TLD by summing a plurality of pixel data for a plurality of pixels PX included in the input image data IDAT.

[0069] The adder 340 may calculate the frame stress FS by summing (or adding) the total threshold voltage shift amount TVTHSA and the total luminance data TLD. According to some example embodiments, the total luminance calculator 330 may calculate the frame stress FS in any manner such that the frame stress FS may increase as the total luminance data TLD increases, and may increase as the total threshold voltage shift amount TVTHSA increases. For example, the total luminance calculator 330 may calculate the frame stress FS by multiplying the total luminance data TLD by a coefficient corresponding to the total threshold voltage shift amount TVTHSA.

[0070] The compensation target determination block 350 may determine a target compensation voltage level TCVL based on the frame stress FS. The compensation target determination block 350 may determine the target compensation voltage level TCVL such that the target compensation voltage level TCVL increases as the frame stress FS increases. According to some example embodiments, the compensation target determination block 350 may compare the frame stress FS with a reference stress, may determine the target compensation voltage level TCVL as a default compensation voltage level (e.g., approximately 0V) when the frame stress FS is less than or equal to the reference stress, and may increase the target compensation voltage level TCVL linearly proportional to the frame stress FS as the frame stress FS increases when the frame stress FS is greater than the reference stress.

[0071] For example, the compensation target determination block 350 may store parameters of a first-order equation (such as a slope parameter and an offset parameter) so that the target compensation voltage level TCVL increases linearly proportionally to the frame stress FS. According to some example embodiments, the compensation target determination block 350 may compare the frame stress FS with a reference stress, may determine the target compensation voltage level TCVL as a default compensation voltage level (e.g., approximately 0 volts) when the frame stress FS is less than or equal to the reference stress, and may increase the target compensation voltage level TCVL by using an N-order equation of the frame stress FS when the frame stress FS is greater than the reference stress, where N is an integer greater than 1. For example, the compensation target determination block 350 may include a look-up table to increase the target compensation voltage level TCVL by using an N-order equation of the frame stress FS or to determine the target compensation voltage level TCVL corresponding to the frame stress FS.

[0072] According to some example embodiments, the compensation target determination block 350 may store M frame stresses FS in M frame periods (where M is an integer greater than 0), may calculate an average value of the M frame stresses FS, and may determine the target compensation voltage level TCVL according to the average value of the M frame stresses FS. Therefore, even if the input image data IDAT or the total luminance data TLD is changed sharply, the target compensation voltage level TCVL can be prevented from being changed sharply.

[0073] In addition, according to some example embodiments, in a case where the frame stress FS (by an amount greater than a reference amount (e.g., a set or predetermined reference amount)) is changed from a first frame stress to a second frame stress, the compensation target determination block 350 may gradually change the target compensation voltage level TCVL from a first target compensation voltage level corresponding to the first frame stress to a second target compensation voltage level corresponding to the second frame stress within a transition time corresponding to a plurality of frame periods. Therefore, the target compensation voltage level TCVL can be changed smoothly, and thus, the luminance of the image displayed by the display panel 110 can be changed smoothly.

[0074] In addition, according to some example embodiments, the compensation target determination block 350 may receive a dimming signal representing a dimming level and may determine the target compensation voltage level TCVL based on the frame stress FS and the dimming signal. For example, the compensation target determination block 350 may determine the target compensation voltage level TCVL such that the target compensation voltage level TCVL increases as the frame stress FS increases and the target compensation voltage level TCVL increases as the dimming level increases (or the luminance level decreases). Therefore, a fine dimming mode can be implemented by using the target compensation voltage level TCVL that can be finely adjusted or tuned.

[0075] The data compensation block 360 may generate compensated image data CDAT by compensating input image data IDAT based on a target compensation voltage level TCVL. According to some example embodiments, the data compensation block 360 may generate a plurality of pixel compensation data based on the difference between the target compensation voltage level TCVL and a plurality of threshold voltage levels corresponding to a plurality of threshold voltage data, and may generate the compensated image data CDAT by adding the plurality of pixel compensation data to the input image data IDAT.

[0076] The data compensation block 360 may provide the compensated image data CDAT to the data driver 130, and the data driver 130 may provide a data voltage DV corresponding to the compensated image data CDAT to the plurality of pixels PX. For example, in a case where the target compensation voltage level TCVL is determined to be a default compensation voltage level of about 0 volts, pixel compensation data or threshold voltage data corresponding to the threshold voltage VTH of the driving transistor T1 may be added to each pixel data in the input image data IDAT, and the data voltage DV obtained by adding the threshold voltage VTH to the voltage corresponding to the gray level of the pixel data may be applied to each pixel PX.

[0077] According to some example embodiments, in a case where the target compensation voltage level TCVL is determined to be about 0.2 volts higher than the default compensation voltage level, pixel compensation data corresponding to the difference between the threshold voltage VTH of the driving transistor T1 and about 0.2 volts may be added to each pixel data in the input image data IDAT, and the data voltage DV obtained by adding the difference between the threshold voltage VTH and about 0.2 volts to the voltage corresponding to the gray level of the pixel data may be applied to each pixel PX. In this case, compared with the case where the target compensation voltage level TCVL is determined to be the default compensation voltage level of about 0 volts, the data voltage DV may be reduced, the power consumption of the display device 100 may be lowered, and the deterioration process of the driving transistor T1 may be delayed.

[0078] According to some example embodiments, the plurality of pixels PX may include red pixels, green pixels, and blue pixels, and determining a total threshold voltage shift amount TVTHSA, determining a total luminance data TLD, determining a frame stress FS, and determining a target compensation voltage level TCVL may be performed according to the colors of the plurality of pixels PX. For example, the threshold voltage shift calculation block 310 may determine a red total threshold voltage shift amount of red pixels, a green total threshold voltage shift amount of green pixels, and a blue total threshold voltage shift amount of blue pixels as the total threshold voltage shift amount TVTHSA.

[0079] The frame stress calculation block 320 may determine the total luminance data for red pixels, the total luminance data for green pixels, and the total luminance data for blue pixels as the total luminance data TLD. Further, as the frame stress FS, the frame stress calculation block 320 may determine a red frame stress based on the total red luminance data and the red total threshold voltage offset, may determine a green frame stress based on the total green luminance data and the green total threshold voltage offset, and may determine a blue frame stress based on the total blue luminance data and the blue total threshold voltage offset.

[0080] The compensation target determination block 350 may determine a red target compensation voltage level corresponding to the red frame stress, a green target compensation voltage level corresponding to the green frame stress, and a blue target compensation voltage level corresponding to the blue frame stress as the target compensation voltage level TCVL. The data compensation block 360 may generate compensated image data CDAT by compensating the input image data IDAT based on the red target compensation voltage level, the green target compensation voltage level, and the blue target compensation voltage level. In this case, since the red target compensation voltage level, the green target compensation voltage level, and the blue target compensation voltage level are determined to correspond to red pixels, green pixels, and blue pixels, respectively, color coordinate distortion caused by a change in the target compensation voltage level TCVL does not occur.

[0081] Further, according to some example embodiments, the display panel 110 may be divided into a plurality of pixel blocks, and determining the total threshold voltage offset TVTHSA, determining the total luminance data TLD, determining the frame stress FS, and determining the target compensation voltage level TCVL may be performed for each pixel block. For example, the threshold voltage offset calculation block 310 may determine the total threshold voltage offsets of the plurality of pixel blocks as the total threshold voltage offset TVTHSA.

[0082] The frame stress calculation block 320 may determine the total block luminance data for the plurality of pixel blocks as the total luminance data TLD, and may determine the frame stress of the plurality of blocks based on the total block luminance data and the total threshold voltage offsets of the plurality of blocks as the frame stress FS. The compensation target determination block 350 may determine the target compensation voltage levels of the plurality of blocks for the plurality of pixel blocks as the target compensation voltage level TCVL. The data compensation block 360 may generate compensated image data CDAT by compensating the input image data IDAT based on the target compensation voltage levels of the plurality of blocks.

[0083] In addition, according to some example embodiments, when the input image data IDAT is black image data representing 0 gray level (or low gray image data representing a gray level lower than the reference gray level), the controller 160 may enable the degradation of the driving transistor T1 to be reduced or restored. For example, the controller 160 may receive black image data as the input image data IDAT from an external host processor, or may generate the input image data IDAT corresponding to the black image data in the off mode or standby mode of the display device 100.

[0084] In response to the received or generated black image data, the controller 160 may determine the target compensation voltage level TCVL as a positive voltage level, and may generate compensation image data CDAT representing a negative gray level based on the positive target compensation voltage level TCVL. The data driver 130 may provide a data voltage DV (having a negative voltage level or lower than the threshold voltage VTH) corresponding to the compensation image data CDAT representing a negative gray level to the plurality of pixels PX, and the threshold voltage VTH of the driving transistor T1 of the plurality of pixels PX may be offset in the negative direction based on the data voltage DV. Therefore, the degradation of the driving transistor T1 can be reduced or restored.

[0085] As described above, in the display device 100 according to some example embodiments, the frame stress FS may be determined based on the total luminance data TLD corresponding to the total luminance of the image represented by the input image data IDAT and the total threshold voltage shift amount TVTHSA corresponding to the degradation degree of the plurality of pixels PX or the degradation degree of the driving transistor T1, and the target compensation voltage level TCVL may be determined according to the frame stress FS. Therefore, in the display device 100 according to some example embodiments, power consumption can be reduced, the degradation of the driving transistor T1 can be reduced or restored, and a micro dimming mode can be achieved.

[0086] Figure 4 is a flowchart showing a method of operating a display device according to some example embodiments, Figure 5 is a diagram showing an example of frame stress according to total luminance data, Figure 6 is a diagram showing an example of a target compensation voltage level according to frame stress according to some example embodiments, Figure 7 is a diagram showing another example of a target compensation voltage level according to frame stress according to some example embodiments, Figure 8A is a diagram showing an example of a data voltage corresponding to compensation image data when the target compensation voltage level is determined as the default compensation voltage level, Figure 8B is a diagram showing an example of a data voltage corresponding to compensation image data when the target compensation voltage level is determined as a voltage level higher than the default compensation voltage level.

[0087] Referring toFigure 1 , Figure 3 and Figure 4 , in a method of operating a display device 100 including a plurality of pixels PX, a sense data memory 150 may store sense data SD (S410) of threshold voltages of driving transistors of the plurality of pixels PX, and a threshold voltage offset calculation block 310 may determine a total threshold voltage shift amount TVTHSA of the driving transistors of the plurality of pixels PX based on the sense data SD (S420). According to some example embodiments, the threshold voltage offset calculation block 310 may calculate a current total threshold voltage data by summing a plurality of threshold voltage data included in the sense data SD, and may calculate the total threshold voltage shift amount TVTHSA by subtracting an initial total threshold voltage data before deterioration of the plurality of pixels PX from the current total threshold voltage data.

[0088] A frame stress calculation block 320 may determine a total luminance data TLD based on input image data IDAT (S430), and may determine a frame stress FS based on the total luminance data TLD and the total threshold voltage shift amount TVTHSA (S440). According to some example embodiments, the frame stress calculation block 320 may calculate the total luminance data TLD by summing a plurality of pixel data included in the input image data IDAT, and may calculate the frame stress FS by summing the total threshold voltage shift amount TVTHSA and the total luminance data TLD.

[0089] Figure 5 Examples 510 of the frame stress FS according to the total luminance data TLD in the case where the plurality of pixels PX are not deteriorated, examples 520 of the frame stress FS according to the total luminance data TLD in the case where the threshold voltages of the driving transistors of the plurality of pixels PX are shifted in the positive direction (or in the case where the driving transistors are deteriorated), and examples 530 of the frame stress FS according to the total luminance data TLD in the case where the threshold voltages of the driving transistors of the plurality of pixels PX are shifted in the negative direction are shown.

[0090] For example, as Figure 5 shown, in the case where the threshold voltages of the driving transistors of the plurality of pixels PX are shifted in the positive direction (or in the case where the driving transistors are deteriorated), the frame stress FS may be calculated by adding a first total threshold voltage shift amount TVTHSA1 corresponding to the positive direction shift of the threshold voltage of the driving transistor to the total luminance data TLD. Further, in the case where the threshold voltages of the driving transistors of the plurality of pixels PX are shifted in the negative direction, the frame stress FS may be calculated by subtracting a second total threshold voltage shift amount TVTHSA2 corresponding to the negative direction shift of the threshold voltage of the driving transistor from the total luminance data TLD.

[0091] Further, as Figure 5As shown, when multiple pixels PX are not deteriorated and the total luminance data TLD is greater than the first total luminance data TLD1, the frame stress FS can be greater than the reference stress RSTRESS. However, in the case where the driving transistor is deteriorated, when the total luminance data TLD is greater than the second total luminance data TLD2 which is lower than the first total luminance data TLD1, the frame stress FS will be greater than the reference stress RSTRESS. Therefore, in the case where the driving transistor is deteriorated, at the relatively low second total luminance data TLD2, the frame stress FS will be greater than or equal to the reference stress RSTRESS. In addition, in the case where the threshold voltage shifts in the negative direction, when the total luminance data TLD is greater than the third total luminance data TLD3 which is higher than the first total luminance data TLD1, the frame stress FS will be greater than the reference stress RSTRESS. Therefore, in the case where the threshold voltage shifts in the negative direction, at the relatively high third total luminance data TLD3, the frame stress FS will be greater than or equal to the reference stress RSTRESS.

[0092] The compensation target determination block 350 can determine the target compensation voltage level TCVL based on the frame stress FS (S450). The compensation target determination block 350 can determine the target compensation voltage level TCVL such that the target compensation voltage level TCVL increases as the frame stress FS increases.

[0093] According to some example embodiments, as Figure 6 shown, the compensation target determination block 350 can compare the frame stress FS with the reference stress RSTRESS, can determine the target compensation voltage level TCVL as the default compensation voltage level DCVL (e.g., approximately 0 volts) when the frame stress FS is less than or equal to the reference stress RSTRESS, and can increase the target compensation voltage level TCVL linearly proportionally to the frame stress FS as the frame stress FS increases when the frame stress FS is greater than the reference stress RSTRESS. For example, the compensation target determination block 350 can store the parameters of a first-order equation (such as a slope parameter and an offset parameter) to increase the target compensation voltage level TCVL linearly proportionally to the frame stress FS. In addition, according to some example embodiments, as Figure 6 and Figure 7 shown, the compensation target determination block 350 can store the compensation target upper limit ULVL, and can determine the target compensation voltage level TCVL such that the target compensation voltage level TCVL does not exceed the compensation target upper limit ULVL.

[0094] According to some example embodiments, as Figure 7As shown, the compensation target determination block 350 may compare the frame stress FS with the reference stress RSTRESS, may determine the target compensation voltage level TCVL as the default compensation voltage level DCVL (e.g., approximately 0 volts) when the frame stress FS is less than or equal to the reference stress RSTRESS, and may increase the target compensation voltage level TCVL as the frame stress FS increases by using an Nth-order equation of the frame stress FS, where N is an integer greater than 1. For example, the compensation target determination block 350 may include a look-up table to increase the target compensation voltage level TCVL or determine the target compensation voltage level TCVL corresponding to the frame stress FS by using an Nth-order equation of the frame stress FS.

[0095] The data compensation block 360 may generate compensated image data CDAT by compensating the input image data IDAT based on the target compensation voltage level TCVL (S460), and the data driver 130 may provide a data voltage DV to a plurality of pixels PX based on the compensated image data CDAT (S470). According to some example embodiments, the data compensation block 360 may generate a plurality of pixel compensation data based on the difference between the target compensation voltage level TCVL and a plurality of threshold voltage levels corresponding to a plurality of threshold voltage data, and may generate the compensated image data CDAT by adding the plurality of pixel compensation data to the input image data IDAT.

[0096] For example, as Figure 8A shown, when the target compensation voltage level TCVL is determined as the default compensation voltage level DCVL of approximately 0 volts, the threshold voltage data for the pixel PX represents a threshold voltage VTH of approximately 0.5 volts, and the input image data IDAT for the pixel PX corresponds to a data voltage DV of approximately 2 volts, the data compensation block 360 may determine the pixel compensation data PCD for the pixel PX as the difference of approximately 0.5 volts between the target compensation voltage level TCVL corresponding to approximately 0 volts and the threshold voltage VTH of approximately 0.5 volts, and may generate the compensated image data CDAT corresponding to a data voltage DV of approximately 2.5 volts by adding the pixel compensation data PCD corresponding to approximately 0.5 volts to the input image data IDAT for the pixel PX.

[0097] In another example, as Figure 8BAs shown, when the target compensation voltage level TCVL is determined to be approximately 0.2 volts higher than the default compensation voltage level DCVL, the threshold voltage data for pixel PX represents a threshold voltage VTH of approximately 0.5 volts, and the input image data IDAT for pixel PX corresponds to a data voltage DV of approximately 2 volts, the data compensation block 360 can determine the pixel compensation data PCD for pixel PX to correspond to a difference of approximately 0.3 volts between the target compensation voltage level TCVL of approximately 0.2 volts and the threshold voltage VTH of approximately 0.5 volts, and can generate compensation image data CDAT corresponding to a data voltage DV of approximately 2.3 volts by adding the pixel compensation data PCD corresponding to approximately 0.3 volts to the input image data IDAT for pixel PX. Therefore, compared with the case where the target compensation voltage level TCVL is determined to be the default compensation voltage level DCVL of approximately 0 volts, the data voltage DV for multiple pixels PX can be reduced, the power consumption of the display device 100 can be lowered, and the deterioration process of the driving transistors of multiple pixels PX can be delayed.

[0098] Figure 9 is a flowchart showing a method of operating a display device according to some example embodiments, Figure 10 is a diagram showing an example of determining a target compensation voltage level based on an average value of M frame stresses.

[0099] Referring to Figure 1 、 Figure 3 and Figure 9 , in a method of operating a display device 100 including multiple pixels PX, the sense data memory 150 can store sense data SD of the threshold voltages of the driving transistors of multiple pixels PX (S610), and the threshold voltage offset calculation block 310 can determine the total threshold voltage offset amount TVTHSA of the driving transistors of multiple pixels PX based on the sense data SD (S620). The frame stress calculation block 320 can determine the total luminance data TLD based on the input image data IDAT (S630), and can determine the frame stress FS based on the total luminance data TLD and the total threshold voltage offset amount TVTHSA (S640).

[0100] The compensation target determination block 350 can store M frame stresses FS in M frame periods (where M is an integer greater than 0) (S650), can calculate the average value of the M frame stresses FS (S660), and can determine the target compensation voltage level TCVL according to the average value of the M frame stresses FS (S670). For example, as Figure 10As shown, the first target compensation voltage level TCVL1 in the M-th frame period FPM can be determined based on the average value of the first frame stress FS1 to the M-th frame stress FSM in the first frame period FP1 to the M-th frame period FPM. The second target compensation voltage level TCVL2 in the (M + 1)-th frame period FPM+1 can be determined based on the average value of the second frame stress FS2 to the (M + 1)-th frame stress FSM+1 in the second frame period FP2 to the (M + 1)-th frame period FPM+1. The third target compensation voltage level TCVL3 in the (M + 2)-th frame period FPM+2 can be determined based on the average value of the third frame stress FS3 to the (M + 2)-th frame stress FSM+2 in the third frame period FP3 to the (M + 2)-th frame period FPM+2. Therefore, even if the input image data IDAT or the total luminance data TLD changes abruptly, the target compensation voltage level TCVL can be prevented from changing abruptly.

[0101] The data compensation block 360 can generate compensated image data CDAT by compensating the input image data IDAT based on the target compensation voltage level TCVL (S680). The data driver 130 can supply a data voltage DV to the plurality of pixels PX based on the compensated image data CDAT (S690).

[0102] Figure 11 is a flowchart showing a method of operating a display device according to some example embodiments, Figure 12 is a diagram showing an example in which the target compensation voltage level is gradually changed during a transition time corresponding to a plurality of frame periods.

[0103] Referring to Figure 1 、 Figure 3 and Figure 11 In a method of operating a display device 100 including a plurality of pixels PX, the sense data memory 150 can store sense data SD of the threshold voltages of the driving transistors of the plurality of pixels PX (S710). The threshold voltage offset calculation block 310 can determine the total threshold voltage offset amount TVTHSA of the driving transistors of the plurality of pixels PX based on the sense data SD (S720). The frame stress calculation block 320 can determine the total luminance data TLD based on the input image data IDAT (S730), and can determine the frame stress FS based on the total luminance data TLD and the total threshold voltage offset amount TVTHSA (S740).

[0104] The compensation target determination block 350 can gradually change the target compensation voltage level TCVL according to the frame stress FS within a plurality of frame periods (S750). According to some example embodiments, as Figure 12As shown, in the case where the frame stress FS is changed from a first frame stress to a second frame stress in a first frame period FP1 by an amount greater than a reference amount (e.g., a set or predetermined reference amount), the compensation target determination block 350 can gradually change the target compensation voltage level TCVL from a first target compensation voltage level TCVL1 corresponding to the first frame stress to a second target compensation voltage level TCVL2 corresponding to the second frame stress within a transition time TT corresponding to a plurality of frame periods. For example, the compensation target determination block 350 can store a unit time UT and a unit change amount UCA corresponding to at least one frame period, and can change the target compensation voltage level TCVL by the unit change amount UCA every unit time UT. In addition, in the case where the frame stress FS is changed from the second frame stress to a third frame stress in a second frame period FP2, the compensation target determination block 350 can gradually change the target compensation voltage level TCVL from the second target compensation voltage level TCVL2 corresponding to the second frame stress to a third target compensation voltage level TCVL3 corresponding to the third frame stress. Therefore, the target compensation voltage level TCVL can be smoothly changed, and thus, the luminance of the image displayed by the display panel 110 can be smoothly changed.

[0105] The data compensation block 360 can generate compensated image data CDAT by compensating the input image data IDAT based on the target compensation voltage level TCVL (S760), and the data driver 130 can supply a data voltage DV to a plurality of pixels PX based on the compensated image data CDAT (S770).

[0106] Figure 13 is a block diagram showing a controller included in a display device according to some example embodiments.

[0107] Referring to Figure 13 , the controller 160a can include a threshold voltage shift calculation block 310, a frame stress calculation block 320, a compensation target determination block 350a, and a data compensation block 360. Except that the compensation target determination block 350a can also receive a dimming signal SDIM, Figure 13 the controller 160a of Figure 3 can have a similar configuration and similar operations to the controller 160 of

[0108] The compensation target determination block 350a may receive a dimming signal SDIM representative of a dimming level, and may determine a target compensation voltage level TCVL based on the frame stress FS and the dimming signal SDIM. For example, the compensation target determination block 350a may determine the target compensation voltage level TCVL such that the target compensation voltage level TCVL increases as the frame stress FS increases, and the target compensation voltage level TCVL increases as the dimming level increases (or the brightness level decreases). Accordingly, a fine dimming mode may be implemented by using the target compensation voltage level TCVL that can be finely adjusted or tuned.

[0109] Figure 14 is a flowchart illustrating a method of operating a display device according to some example embodiments.

[0110] Referring to Figure 1 、 Figure 13 and Figure 14 In a method of operating a display device 100 including a plurality of pixels PX, the sense data memory 150 may store sense data SD of threshold voltages of driving transistors of the plurality of pixels PX (S810), and the threshold voltage offset calculation block 310 may determine a total threshold voltage offset amount TVTHSA of the driving transistors of the plurality of pixels PX based on the sense data SD (S820). The frame stress calculation block 320 may determine total luminance data TLD based on input image data IDAT (S830), and may determine a frame stress FS based on the total luminance data TLD and the total threshold voltage offset amount TVTHSA (S840).

[0111] The compensation target determination block 350a may receive a dimming signal SDIM representative of a dimming level (S850), and may determine a target compensation voltage level TCVL based on the frame stress FS and the dimming signal SDIM (S860). For example, the compensation target determination block 350a may determine the target compensation voltage level TCVL such that the target compensation voltage level TCVL increases as the frame stress FS increases, and the target compensation voltage level TCVL increases as the dimming level increases. Accordingly, a fine dimming mode may be implemented by using the target compensation voltage level TCVL that can be finely adjusted or tuned.

[0112] The data compensation block 360 may generate compensated image data CDAT by compensating the input image data IDAT based on the target compensation voltage level TCVL (S870), and the data driver 130 may supply a data voltage DV to the plurality of pixels PX based on the compensated image data CDAT (S880).

[0113] Figure 15 is a block diagram illustrating a controller included in a display device according to some example embodiments.

[0114] Referring toFigure 15 The controller 160b may include a threshold voltage shift calculation block 310b, a frame stress calculation block 320b, a compensation target determination block 350b, and a data compensation block 360b. The display device 100 including the controller 160b may include red pixels, green pixels, and blue pixels.

[0115] The threshold voltage shift calculation block 310b may determine a red total threshold voltage shift amount RTVTHSA for red pixels, a green total threshold voltage shift amount GTVTHSA for green pixels, and a blue total threshold voltage shift amount BTVTHSA for blue pixels.

[0116] The frame stress calculation block 320b may include a red total luminance calculator 331, a green total luminance calculator 332, and a blue total luminance calculator 333, as well as a first adder 341, a second adder 342, and a third adder 343. The red total luminance calculator 331 may determine red total luminance data RTLD for red pixels, the green total luminance calculator 332 may determine green total luminance data GTLD for green pixels, and the blue total luminance calculator 333 may determine blue total luminance data BTLD for blue pixels. The first adder 341 may determine a red frame stress RFS based on the red total luminance data RTLD and the red total threshold voltage shift amount RTVTHSA, the second adder 342 may determine a green frame stress GFS based on the green total luminance data GTLD and the green total threshold voltage shift amount GTVTHSA, and the third adder 343 may determine a blue frame stress BFS based on the blue total luminance data BTLD and the blue total threshold voltage shift amount BTVTHSA.

[0117] The compensation target determination block 350b may determine a red target compensation voltage level RTCVL corresponding to the red frame stress RFS, a green target compensation voltage level GTCVL corresponding to the green frame stress GFS, and a blue target compensation voltage level BTCVL corresponding to the blue frame stress BFS.

[0118] The data compensation block 360b may generate compensated image data CDAT by compensating the input image data IDAT based on the red target compensation voltage level RTCVL, the green target compensation voltage level GTCVL, and the blue target compensation voltage level BTCVL. In this case, since the red target compensation voltage level RTCVL, the green target compensation voltage level GTCVL, and the blue target compensation voltage level BTCVL are determined to correspond to red pixels, green pixels, and blue pixels, respectively, color coordinate distortion does not occur.

[0119] Figure 16 is a flowchart illustrating a method of operating a display device according to some example embodiments.

[0120] Reference Figure 1 、 Figure 15 and Figure 16 In a method of operating a display device 100 including a plurality of pixels PX, a sense data memory 150 may store sense data SD (S910) of threshold voltages of driving transistors of the plurality of pixels PX.

[0121] A threshold voltage offset calculation block 310b may determine a red total threshold voltage shift amount RTVTHSA of red pixels, a green total threshold voltage shift amount GTVTHSA of green pixels, and a blue total threshold voltage shift amount BTVTHSA of blue pixels (S920).

[0122] A frame stress calculation block 320b may determine a red total luminance data RTLD for red pixels, a green total luminance data GTLD for green pixels, and a blue total luminance data BTLD for blue pixels based on input image data IDAT (S930).

[0123] The frame stress calculation block 320b may determine a red frame stress RFS based on the red total luminance data RTLD and the red total threshold voltage shift amount RTVTHSA, may determine a green frame stress GFS based on the green total luminance data GTLD and the green total threshold voltage shift amount GTVTHSA, and may determine a blue frame stress BFS based on the blue total luminance data BTLD and the blue total threshold voltage shift amount BTVTHSA (S940).

[0124] A compensation target determination block 350b may determine a red target compensation voltage level RTCVL corresponding to the red frame stress RFS, a green target compensation voltage level GTCVL corresponding to the green frame stress GFS, and a blue target compensation voltage level BTCVL corresponding to the blue frame stress BFS (S950).

[0125] A data compensation block 360b may generate compensated image data CDAT by compensating the input image data IDAT based on the red target compensation voltage level RTCVL, the green target compensation voltage level GTCVL, and the blue target compensation voltage level BTCVL (S960), and a data driver 130 may supply a data voltage DV to the plurality of pixels PX based on the compensated image data CDAT (S970). In this case, since the red target compensation voltage level RTCVL, the green target compensation voltage level GTCVL, and the blue target compensation voltage level BTCVL are determined to correspond to red pixels, green pixels, and blue pixels, respectively, color coordinate distortion does not occur.

[0126] Figure 17 is a block diagram of an electronic device including a display device according to some example embodiments.

[0127] Referring to Figure 11 , the electronic device 1100 may include a processor 1110, a memory device 1120, a storage device 1130, an input / output (I / O) device 1140, a power supply 1150, and a display device 1160. The electronic device 1100 may also include a plurality of ports for communicating with a video card, a sound card, a memory card, a universal serial bus (USB) device, other electronic devices, and the like.

[0128] The processor 1110 may perform various computing functions or tasks. The processor 1110 may be an application processor (AP), a microprocessor, a central processing unit (CPU), or the like. The processor 1110 may be coupled to other components via an address bus, a control bus, a data bus, and the like. In addition, according to some example embodiments, the processor 1110 may also be coupled to an expansion bus such as a peripheral component interconnect (PCI) bus.

[0129] The memory device 1120 may store data for the operation of the electronic device 1100. For example, the memory device 1120 may include at least one non-volatile memory device such as an erasable programmable read-only memory (EPROM) device, an electrically erasable programmable read-only memory (EEPROM) device, a flash memory device, a phase change random access memory (PRAM) device, a resistive random access memory (RRAM) device, a nano floating gate memory (NFGM) device, a polymer random access memory (PoRAM) device, a magnetic random access memory (MRAM) device, a ferroelectric random access memory (FRAM) device, etc., and / or at least one volatile memory device such as a dynamic random access memory (DRAM) device, a static random access memory (SRAM) device, a mobile dynamic random access memory (mobile DRAM) device, etc.

[0130] The storage device 1130 may be a solid state drive (SSD) device, a hard disk drive (HDD) device, a CD-ROM device, etc. The I / O device 1140 may be an input device such as a keyboard, a keypad, a mouse, a touch screen, etc., and an output device such as a printer, a speaker, etc. The power supply 1150 may power the operation of the electronic device 1100. The display device 1160 may be coupled to other components via a bus or other communication link.

[0131] In the display device 1160, the frame stress may be determined based on total luminance data corresponding to the total luminance of an image represented by input image data and a total threshold voltage shift amount corresponding to the deterioration degree of a plurality of pixels or the deterioration degree of a driving transistor, and a target compensation voltage level may be determined according to the frame stress. Accordingly, in the display device 1160 according to some example embodiments, power consumption may be reduced, deterioration of the driving transistor may be reduced or restored, and a micro dimming mode may be implemented.

[0132] The inventive concept may be applied to any electronic device 1100 including the display device 1160. For example, the inventive concept may be applied to a television (TV), a digital TV, a 3D TV, a smart phone, a wearable electronic device, a tablet computer, a mobile phone, a personal computer (PC), a home appliance, a laptop computer, a personal digital assistant (PDA), a portable multimedia player (PMP), a digital camera, a music player, a portable game controller, a navigation device, and the like.

[0133] The foregoing is illustrative of some aspects of example embodiments and is not to be construed as limiting some aspects of example embodiments. Although some example embodiments have been described, it will be readily understood by those skilled in the art that many modifications are possible in the example embodiments without materially departing from the innovative teachings and characteristics of the embodiments according to the inventive concept. Accordingly, all such modifications are intended to be included within the scope of the embodiments according to the inventive concept as defined in the claims and their equivalents. Accordingly, it will be understood that the foregoing is illustrative of various example embodiments and is not to be construed as limited to the specific example embodiments disclosed, and modifications to the disclosed example embodiments and other example embodiments are intended to be included within the scope of the appended claims and their equivalents.

Claims

1. A display device, the display device comprising: A display panel including a plurality of pixels; A sensing data memory configured to store sensing data of threshold voltages of driving transistors of the plurality of pixels; A controller configured to determine a total threshold voltage offset of the driving transistors of the plurality of pixels based on the sensing data, determine total luminance data based on input image data, determine a frame stress based on the total luminance data and the total threshold voltage offset, determine a target compensation voltage level based on the frame stress, and generate compensated image data by compensating the input image data based on the target compensation voltage level, wherein the controller is configured to calculate the total luminance data by summing a plurality of pixel data included in the input image data, and calculate the frame stress by summing the total threshold voltage offset and the total luminance data, and wherein the controller is configured to: compare the frame stress with a reference stress; in response to the frame stress being less than or equal to the reference stress, determine the target compensation voltage level as a default compensation voltage level; in response to the frame stress being greater than the reference stress, increase the target compensation voltage level as the frame stress increases; and A data driver configured to provide data voltages to the plurality of pixels based on the compensated image data.

2. The display device according to claim 1, wherein, The controller is configured to: In response to the frame stress being greater than the reference stress, linearly increase the target compensation voltage level in proportion to the frame stress as the frame stress increases.

3. The display device according to claim 1, wherein, The controller is configured to: In response to the frame stress being greater than the reference stress, increase the target compensation voltage level by using an Nth order equation of the frame stress as the frame stress increases, where N is an integer greater than 1.

4. The display device according to claim 1, wherein, The controller is configured to generate a plurality of pixel compensation data based on a difference between the target compensation voltage level and a plurality of threshold voltage levels corresponding to a plurality of threshold voltage data included in the sensing data, and generate the compensated image data by adding the plurality of pixel compensation data to the input image data.

5. The display device according to claim 1, the display device further comprising: A sensing circuit coupled to a plurality of sensing lines, wherein the data driver is configured to provide a reference voltage to the plurality of pixels through a plurality of data lines during a sensing period, wherein the sensing circuit is configured to receive a plurality of sensing voltages from the plurality of pixels through the plurality of sensing lines during the sensing period, and generate the sensing data corresponding to a difference between the reference voltage and the plurality of sensing voltages, and wherein the controller is configured to receive the sensing data from the sensing circuit and write the sensing data into the sensing data memory.

6. The display device according to claim 1, wherein The controller includes: A threshold voltage offset calculation block, configured to: calculate current total threshold voltage data by summing a plurality of threshold voltage data included in the sensed data, and calculate the total threshold voltage offset amount by subtracting the initial total threshold voltage data before degradation of the plurality of pixels from the current total threshold voltage data; A frame stress calculation block, configured to: calculate the total luminance data by summing the plurality of pixel data included in the input image data, and calculate the frame stress by summing the total threshold voltage offset amount and the total luminance data; A compensation target determination block, configured to: determine the target compensation voltage level based on the frame stress; and A data compensation block, configured to: generate a plurality of pixel compensation data based on the difference between the target compensation voltage level and a plurality of threshold voltage levels corresponding to the plurality of threshold voltage data, and generate the compensated image data by adding the plurality of pixel compensation data to the input image data.

7. The display device according to claim 1, wherein, The plurality of pixels include red pixels, green pixels, and blue pixels, and wherein, the controller is configured to: Determine the total threshold voltage offset amount of the red total threshold voltage offset amount of the red pixels, the green total threshold voltage offset amount of the green pixels, and the blue total threshold voltage offset amount of the blue pixels; Determine the red total luminance data for the red pixels, the green total luminance data for the green pixels, and the blue total luminance data for the blue pixels as the total luminance data; Determine the red frame stress based on the red total luminance data and the red total threshold voltage offset amount, the green frame stress based on the green total luminance data and the green total threshold voltage offset amount, and the blue frame stress based on the blue total luminance data and the blue total threshold voltage offset amount as the frame stress; Determine the red target compensation voltage level corresponding to the red frame stress, the green target compensation voltage level corresponding to the green frame stress, and the blue target compensation voltage level corresponding to the blue frame stress as the target compensation voltage level; and Generate the compensated image data by compensating the input image data based on the red target compensation voltage level, the green target compensation voltage level, and the blue target compensation voltage level.

8. The display device according to any one of claims 1 to 7, wherein, In the case where the input image data is black image data representing a 0 gray level, the controller is configured to generate the compensated image data representing a negative gray level based on the target compensation voltage level as a positive voltage level, and the data driver is configured to provide the data voltage corresponding to the compensated image data representing the negative gray level to the plurality of pixels, so that the threshold voltage of the driving transistor is offset in the negative direction.

9. A method of operating a display device, the display device including a plurality of pixels, the method including: Storing sensed data of threshold voltages of driving transistors of the plurality of pixels; Determining a total threshold voltage offset amount of the driving transistors of the plurality of pixels based on the sensed data; Determine total luminance data based on input image data; Determine frame stress based on the total luminance data and the total threshold voltage offset; Determine a target compensation voltage level based on the frame stress; Generate compensated image data by compensating the input image data based on the target compensation voltage level; And Provide a data voltage to the plurality of pixels based on the compensated image data, wherein the total luminance data is calculated by summing a plurality of pixel data included in the input image data, and the frame stress is calculated by summing the total threshold voltage offset and the total luminance data, and wherein the step of determining a target compensation voltage level based on the frame stress includes: comparing the frame stress with a reference stress; in response to the frame stress being less than or equal to the reference stress, determining the target compensation voltage level as a default compensation voltage level; in response to the frame stress being greater than the reference stress, increasing the target compensation voltage level as the frame stress increases.

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