Display device

Abstract

A display device is provided. The display device includes: a display panel including a plurality of pixels, each pixel including an organic light emitting diode and a driving element, the display panel being configured to display image data on the pixel; a data driver being configured to generate a data voltage corresponding to the image data; a compensation circuit being configured to sense a driving current flowing through the pixel and generate a compensation data voltage that compensates for a threshold voltage of the driving element based on the data voltage and the driving current; a scan driver being configured to generate a first scan signal and a second scan signal provided to the pixel; and a timing controller being configured to generate a control signal for controlling the data driver and the scan driver.

Description

Technical Field

[0001] Aspects of some example embodiments generally relate to a display device and an electronic device having the display device. Background Art

[0002] Recently, since a flat panel display (FPD) device is relatively light and thin compared to a cathode ray tube (CRT) display device, the FPD device has been widely used as a display device of an electronic device. Examples of the FPD device are a liquid crystal display (LCD) device, a field emission display (FED) device, a plasma display panel (PDP) device, and an organic light emitting display (OLED) device. Since the OLED device has various characteristics such as a relatively wide viewing angle, a relatively fast response speed, a relatively thin thickness, a relatively low power consumption, etc., the OLED device has received attention as a next generation display device.

[0003] Each pixel of an OLED device may include an organic light emitting diode and a pixel circuit that drives the organic light emitting diode. The pixel circuit may include a driving element that generates a driving current provided to the organic light emitting diode. As the use time of the organic light emitting display device increases, the driving element may degrade and the threshold voltage of the driving element may change. As the threshold voltage of the driving element changes, the brightness of the pixel may decrease, and the decrease in the brightness of the pixel may reduce the perceived display quality of the OLED device.

[0004] The above information disclosed in this Background section is only for enhancement of understanding of the background and therefore the above information may contain information that does not constitute the prior art. Summary of the invention

[0005] Aspects of some example embodiments may include a display device capable of improving display quality.

[0006] Aspects of some example embodiments may include an electronic device having a display device capable of improving display quality.

[0007] According to some example embodiments of the present disclosure, a display device includes: a display panel including a plurality of pixels, each pixel including an organic light emitting diode and a driving element, the display panel being configured to display image data on the pixels; a data driver configured to generate a data voltage corresponding to the image data; a compensation circuit configured to sense a driving current flowing through the pixels and generate a compensation data voltage that compensates for a threshold voltage of the driving element based on the data voltage and the driving current; a scan driver configured to generate a first scan signal and a second scan signal provided to the pixels; and a timing controller configured to generate control signals for controlling the data driver and the scan driver.

[0008] According to some example embodiments, the compensation circuit may include: a sensing unit configured to sense a driving current and generate a sensing voltage corresponding to the driving current; and a compensation voltage generator configured to generate a compensation data voltage that compensates for a threshold voltage of a driving element based on a data voltage and the sensing voltage.

[0009] According to some example embodiments, the sensing unit may include: a sensing resistor configured to sense the driving current and generate a first sensing voltage corresponding to the driving current; and an amplifier configured to output a second sensing voltage by amplifying the first sensing voltage.

[0010] According to some example embodiments, the compensation voltage generator may include a comparator that compares the data voltage with the second sensing voltage and converts the data voltage into the compensation data voltage.

[0011] According to some example embodiments, the comparator may include a first input terminal configured to receive a data voltage, a second input terminal configured to receive a second sensing voltage, and an output terminal configured to output a compensated data voltage by comparing the data voltage and the second sensing voltage.

[0012] According to some example embodiments, the organic light emitting diode may include an anode electrode and a cathode electrode, and the driving element may include a gate electrode coupled to a first node, a first electrode receiving a first power voltage, and a second electrode coupled to a second node.

[0013] According to some example embodiments, the scan driver may further generate a third scan signal provided to the pixels.

[0014] According to some example embodiments, each pixel may further include: a first switching element including a gate electrode receiving a first scan signal, a first electrode coupled to a compensation data voltage generator, and a second electrode coupled to a first node; a second switching element including a gate electrode receiving a second scan signal, a first electrode coupled to a second node, and a second electrode coupled to an anode electrode of an organic light emitting diode; a third switching element including a gate electrode receiving a third scan signal, a first electrode coupled to a second node, and a second electrode coupled to a sensing unit; and a storage capacitor including a first electrode receiving a first power voltage and a second electrode coupled to the first node.

[0015] According to some example embodiments, in the compensation period of the pixel, the first switching element and the third switching element may be turned on, and the second switching element may be turned off.

[0016] According to some example embodiments, in an emission period of a pixel, the first switching element and the second switching element may be turned on, the third switching element may be turned off, and the compensation data voltage is maintained.

[0017] According to some example embodiments, in an emission period of a pixel, the second switching element may be turned on, and the first switching element and the third switching element may be turned off.

[0018] According to some example embodiments, each pixel may further include: a first switching element including a gate electrode receiving a first scan signal, a first electrode coupled to a compensation data voltage generator, and a second electrode coupled to a first node; a second switching element including a gate electrode receiving a second scan signal, a first electrode coupled to a cathode electrode of an organic light emitting diode, and a second electrode coupled to a sensing unit; and a storage capacitor including a first electrode receiving a first power voltage and a second electrode coupled to the first node.

[0019] According to some example embodiments, in an emission period of a pixel, the second switching element may be turned on, and a driving current may be sensed.

[0020] According to some example embodiments, the compensation circuit may be located in or coupled to the data driver.

[0021] According to some example embodiments of the present disclosure, an electronic device includes: a display device and a processor for controlling the display device. The display device may include: a display panel including a plurality of pixels including an organic light emitting diode and a driving element, the display panel being configured to display image data on the pixels; a data driver configured to generate a data voltage corresponding to the image data; a compensation circuit configured to sense a driving current flowing through the pixel and generate a compensation data voltage for compensating a threshold voltage of the driving element based on the data voltage and the driving current; a scan driver configured to generate a first scan signal and a second scan signal provided to the pixel; and a timing controller configured to generate a control signal for controlling the data driver and the scan driver.

[0022] According to some example embodiments, the compensation circuit may include: a sensing unit configured to sense a driving current and generate a sensing voltage corresponding to the driving current; and a compensation data voltage generator configured to generate a compensation data voltage that compensates for a threshold voltage of a driving element based on the data voltage and the sensing voltage.

[0023] According to some example embodiments, the sensing unit may include: a sensing resistor configured to sense a driving current and generate a first sensing voltage corresponding to the driving current; and an amplifier configured to output a second sensing voltage by amplifying the first sensing voltage. The compensation voltage generator may include a comparator that compares the data voltage with the second sensing voltage and converts the data voltage into the compensated data voltage.

[0024] According to some example embodiments, the organic light emitting diode may include an anode electrode and a cathode electrode, and the driving element may include a gate electrode coupled to a first node, a first electrode receiving a first power voltage, and a second electrode coupled to a second node.

[0025] According to some example embodiments, each pixel may further include: a first switching element including a gate electrode receiving a first scan signal, a first electrode coupled to a compensation data voltage generator, and a second electrode coupled to a first node; a second switching element including a gate electrode receiving a second scan signal, a first electrode coupled to a second node, and a second electrode coupled to an anode electrode of an organic light emitting diode; a third switching element including a gate electrode receiving a third scan signal, a first electrode coupled to a second node, and a second electrode coupled to a sensing unit; and a storage capacitor including a first electrode receiving a first power voltage and a second electrode coupled to the first node.

[0026] According to some example embodiments, each pixel may further include: a first switching element including a gate electrode receiving a first scan signal, a first electrode coupled to a compensation data voltage generator, and a second electrode coupled to a first node; a second switching element including a gate electrode receiving a second scan signal, a first electrode coupled to a cathode electrode of an organic light emitting diode, and a second electrode coupled to a sensing unit; and a storage capacitor including a first electrode receiving a first power voltage and a second electrode coupled to the first node.

[0027] Therefore, the display device according to some example embodiments can prevent or reduce the situation where the brightness of the pixel of the display device is reduced due to the change of the threshold voltage of the driving element by including a compensation circuit, which is coupled to the pixel having a 4T1C structure or a 3T1C structure to sense the driving current flowing through the pixel and generate a compensation data voltage that compensates for the threshold voltage of the driving element included in each pixel by comparing the data voltage with the sensing voltage corresponding to the driving current. Therefore, the display quality of the display device can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Illustrative, non-limiting example embodiments will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings.

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

[0030] Figure 2 It is shown that the Figure 1 Diagram of a compensation circuit and pixels in a display device.

[0031] Figure 3 It is shown Figure 2A circuit diagram of an example of a compensation circuit and a pixel.

[0032] Figure 4 It is shown Figure 3 A timing diagram of an example of a pixel operation.

[0033] Figure 5 It is shown Figure 3 A timing diagram of an example of a pixel operation.

[0034] Figure 6 It is shown Figure 2 A circuit diagram of an example of a compensation circuit and a pixel.

[0035] Figure 7 is a block diagram illustrating an electronic device according to some example embodiments.

[0036] Figure 8 It shows that Figure 7 FIG. 1 is a diagram of an example embodiment in which the electronic device is implemented as a smart phone. DETAILED DESCRIPTION

[0037] Hereinafter, aspects of some example embodiments of the inventive concept will be explained in more detail with reference to the accompanying drawings.

[0038] Figure 1 is a block diagram illustrating a display device according to some example embodiments. Figure 2 It is shown that the Figure 1 Diagram of a compensation circuit and pixels in a display device.

[0039] Reference Figure 1 , the display device 100 may include a display panel 110 , a timing controller 120 , a scan driver 130 , a data driver 140 , and a compensation circuit 150 .

[0040] The display panel 110 may include a plurality of pixels PX including an organic light emitting diode and a driving element. The display panel 110 may include a plurality of scan lines (such as SL1, SL2) and a plurality of data lines DL. Each pixel PX may be electrically coupled to each of the scan lines SL1, SL2 and the data line DL. The scan lines SL1, SL2 may extend in a first direction D1 and be arranged in a second direction D2 perpendicular to the first direction D1. For example, the first scan line SL1 and the second scan line SL2 may be formed in the display panel 110.

[0041] Despite Figure 11 and 2 describe the first scan line SL1 and the second scan line SL2 formed in the display panel 110, but the number of scan lines is not limited thereto. For example, a third scan line may be additionally formed in the display panel 110. The data line DL may extend in the second direction D2 and be arranged in the first direction D1. The first direction D1 may be parallel to the long side of the display panel 110, and the second direction D2 may be parallel to the short side of the display panel 110. Each pixel PX may be formed in the intersection area of ​​the data line DL and the scan line. Each pixel PX may include an organic light emitting diode, a driving element, a switching element, and a storage capacitor. For example, the switching element may be a thin film transistor (TFT). The pixel PX of the display panel 110 may display image data.

[0042] The timing controller 120 may convert the first image data IMG1 provided from the external device into the second image data IMG2, and generate a data control signal CTL_D and a scan control signal CTL_S for controlling the second image data IMG2. The timing controller 120 may convert the first image data IMG1 into the second image data IMG2 by applying an algorithm for compensating display quality (e.g., dynamic capacitance compensation (DCC)) to the first image data IMG1. When the timing controller 120 does not include the algorithm for compensating display quality, the timing controller 120 may output the first image data IMG1 as the second image data IMG2. The timing controller 120 may receive a control signal CON from the external device, and generate a data control signal CTL_D provided to the data driver 140 and a scan control signal CTL_S provided to the scan driver 130. For example, the data control signal CTL_D may include a horizontal start signal and at least one clock signal. For example, the scan control signal CTL_S may include a vertical start signal and at least one clock signal.

[0043] The scan driver 130 may provide scan signals SCAN1 and SCAN2 to the pixel PX through the scan lines SL1 and SL2. The scan driver 130 may generate the scan signals SCAN1 and SCAN2 based on the scan control signal CTL_S provided from the timing controller 120. For example, the scan driver 130 may generate a first scan signal SCAN1 provided to the pixel PX through the first scan line SL1 and a second scan signal SCAN2 provided to the pixel PX through the second scan line SL2. The scan driver 130 may also generate a third scan signal provided to the pixel PX through the third scan line.

[0044] The data driver 140 may generate a data voltage Vdata1 based on the second image data IMG2 and the data control signal CTL_D. The data driver 140 may generate a grayscale voltage corresponding to the second image data IMG2 as the data voltage Vdata1. The data driver 140 may provide the data voltage Vdata1 to the compensation circuit 150.

[0045] The compensation circuit 150 may sense the driving current Id flowing through the pixel PX and generate a compensation data voltage Vdata2 compensating for a threshold voltage of a driving element based on the data voltage Vdata1 and the driving current Id.

[0046] Reference Figure 2 The compensation circuits 150 may be respectively coupled to the data lines DL of the display panel 110 (such as Figure 2 DL1, DL2) and sensing line L_sen (such as Figure 2 1, L_sen1, L_sen2 shown in ). In some example embodiments, each of the plurality of compensation circuits 150 may correspond to each data line DL of the display panel 110. Each compensation circuit 150 may include a sensing unit 152 and a compensation data voltage generator (or compensation data generator or compensation voltage generator) 154. The sensing unit 152 may sense the driving current Id of the pixel PX through the sensing line L_sen and generate a sensing voltage corresponding to the driving current Id. The sensing unit 152 may be coupled to each pixel PX. The sensing unit 152 may sequentially sense the driving current Id of the pixel PX. For example, the sensing unit 152 may include a sensing resistor and an amplifier. The sensing unit 152 may provide a sensing voltage corresponding to the driving current Id to the compensation data voltage generator 154. The compensation data voltage generator 154 may generate a compensation data voltage Vdata2 that compensates for a threshold voltage of a driving element based on the data voltage Vdata1 and the sensing voltage. For example, the compensation data voltage generator 154 may include a comparator. The compensation data voltage generator 154 may provide the compensation data voltage Vdata2 to the pixel PX through the data line DL.

[0047] Despite Figure 1 , the compensation circuit 150 is described as being coupled to the data driver 140, but the compensation circuit 150 is not limited thereto. For example, the compensation circuit 150 may be located in the data driver 140.

[0048] As mentioned above, Figure 1The display device 100 can prevent the driving current Id from changing due to the change of the threshold voltage of the driving element by: sensing the driving current Id flowing through the pixel PX; generating the compensation data voltage Vdata2 that compensates the threshold voltage of the driving element based on the data voltage Vdata1 and the driving current Id; and providing the compensation data voltage Vdata2 to the pixel PX. Therefore, the display quality of the display device 100 can be improved.

[0049] Figure 3 is a diagram showing some example embodiments Figure 2 A circuit diagram of an example of a compensation circuit and a pixel. Figure 4 It is shown Figure 3 A timing diagram of an example of a pixel operation. Figure 5 It is shown Figure 3 A timing diagram of an example of a pixel operation.

[0050] Reference Figure 3 , the compensation circuit 200 may be coupled to the pixel PX. Figure 3 The compensation circuit 200 may correspond to Figure 1 and Figure 2 The compensation circuit 150 is provided. Figure 3 The compensation circuit 200 described in EMBODIMENT 2 may be coupled to the M-th data line DLm and the M-th sensing line L_senm. Figure 3 The pixel PX described in may be one of the pixels coupled to the Mth data line DLm and the Mth sensing line L_senm.

[0051] Reference Figure 3 , the pixel PX may include a driving element TD, a first switching element TS1, a second switching element TS2, a third switching element TS3, a storage capacitor CST, and an organic light emitting diode EL. For example, the driving element TD, the first switching element TS1, the second switching element TS2, and the third switching element TS3 may be P-channel metal oxide semiconductor (PMOS) transistors.

[0052] The driving element TD may include a gate electrode, a first electrode, and a second electrode. The driving element TD may include a gate electrode coupled to the first node N1, a first electrode receiving a first power voltage ELVDD, and a second electrode coupled to the second node N2. For example, the first power voltage ELVDD may be a high power voltage. The driving element TD may generate a driving current Id corresponding to a voltage applied to the first node N1.

[0053] The first switching element TS1 may include a gate electrode receiving a first scan signal SCAN1, a first electrode coupled to an Mth data line DLm, and a second electrode coupled to a first node N1. When the first switching element TS1 is a PMOS transistor, the first switching element TS1 may be turned on in response to the first scan signal SCAN1 having a low level. When the first switching element TS1 is turned on, the compensation data voltage Vdata2 provided through the Mth data line DLm may be provided to the first node N1.

[0054] The second switching element TS2 may include a gate electrode receiving a second scan signal SCAN2, a first electrode coupled to a second node N2, and a second electrode coupled to an anode electrode of the organic light emitting diode EL. When the second switching element TS2 is a PMOS transistor, the second switching element TS2 may be turned on in response to the second scan signal SCAN2 having a low level. When the second switching element TS2 is turned on, a driving current Id generated in the driving element TD may be provided to the organic light emitting diode EL, and the organic light emitting diode EL may emit light.

[0055] The third switching element TS3 may include a gate electrode receiving a third scan signal SCAN3, a first electrode coupled to the second node N2, and a second electrode coupled to the compensation circuit 200. When the third switching element TS3 is a PMOS transistor, the third switching element TS3 may be turned on in response to the third scan signal SCAN3 having a low level. When the third switching element TS3 is turned on, the driving current Id may be provided to the compensation circuit 200 through the third switching element TS3 and the sensing line L_senm.

[0056] The storage capacitor CST may include a first electrode receiving the first power voltage ELVDD and a second electrode coupled to the first node N1. The storage capacitor CST may store a voltage applied to the first node N1.

[0057] The anode electrode of the organic light emitting diode EL may be coupled to the second electrode of the second switching element TS2 , and the cathode electrode of the organic light emitting diode EL may receive the second power voltage ELVSS. For example, the second power voltage ELVSS may be lower than the first power voltage ELVDD.

[0058] Despite Figure 3, an aspect of a pixel PX including a driving element TD, a first switching element TS1, a second switching element TS2, and a third switching element TS3 implemented as a PMOS transistor is described, but the driving element TD, the first switching element TS1, the second switching element TS2, and the third switching element TS3 are not limited thereto. For example, the driving element TD, the first switching element TS1, the second switching element TS2, and the third switching element TS3 may be implemented as an N-channel metal oxide semiconductor (NMOS) transistor.

[0059] The compensation circuit 200 may include a sensing unit 220 and a compensation data voltage generator 240 . Figure 3 The sensing unit 220 and the compensation data voltage generator 240 may be connected with Figure 2 The sensing unit 220 may include a sensing resistor Rsen and an amplifier AMP. The sensing resistor Rsen may generate a first sensing voltage VS1 corresponding to the driving current Id provided through the Mth sensing line L_senm. The amplifier AMP may output a second sensing voltage VS2 by amplifying the first sensing voltage VS1 generated by the sensing resistor Rsen and removing noise. The second sensing voltage VS2 may be provided to the compensation data voltage generator 240. The compensation data voltage generator 240 may include a comparator COM. The comparator COM may compare the data voltage Vdata1 with the second sensing voltage VS2 and convert the data voltage Vdata1 into a compensation data voltage Vdata2. The comparator COM may include a first input terminal IN1 receiving the data voltage Vdata1, a second input terminal IN2 receiving the second sensing voltage VS2, and an output terminal OUT outputting the compensation data voltage Vdata2 by comparing the data voltage Vdata1 with the second sensing voltage VS2.

[0060] The second sensing voltage VS2 may be a voltage corresponding to a reduced driving current Id generated by a driving element TD, wherein a threshold voltage of the driving element TD changes due to degradation. The comparator COM may output a compensation data voltage Vdata2 that compensates for a difference between a data voltage Vdata1 provided from the data driver 140 and a second sensing voltage VS2 provided from the sensing unit 220. That is, the compensation data voltage Vdata2 may have a voltage level that compensates for the reduced driving current Id due to a change in the threshold voltage of the driving element TD. The output terminal OUT of the comparator COM may be coupled to the Mth data line DLm and provide the compensation data voltage Vdata2 to the first electrode of the first switching element TS1 included in the pixel PX. Although in Figure 3, the compensated data voltage generator 240 including the comparator COM is described, but the compensated data voltage generator 240 may not be limited thereto. For example, the compensated data voltage generator 240 may further include a calculator that calculates a difference between the data voltage Vdata1 and the second sensing voltage VS2.

[0061] In some example embodiments, the compensation circuit 200 may further include a memory sensing line L_me. The memory sensing line L_me may be coupled to the output terminal of the amplifier AMP and sense the second sensing voltage VS2. For example, the memory sensing line L_me may be coupled to the memory device of the data driver 140 and store the second sensing voltage VS2 corresponding to the driving current Id. In this case, the data driver 140 may generate a compensation data voltage Vdata2 that compensates for the threshold voltage of the driving element TD based on the second sensing voltage VS2 stored in the memory device. In this case, the compensation data voltage generator 240 may be omitted.

[0062] Reference Figure 4 , the compensation circuit 200 may sense the driving current Id of the pixel PX during the compensation period P1. The first scan signal SCAN1 and the third scan signal SCAN3 having a low level and the second scan signal SCAN2 having a high level may be provided to the pixel PX during the compensation period P1. The first switching element TS1 may be turned on in response to the first scan signal SCAN1, the third switching element TS3 may be turned on in response to the third scan signal SCAN3, and the second switching element TS2 may be turned off in response to the second scan signal SCAN2. Because the first switching element TS1 is turned on, the data voltage Vdata1 provided through the Mth data line DLm may be provided to the first node N1. The driving element TD may generate a driving current Id corresponding to the voltage of the first node N1. Here, the driving current Id may be reduced by a change in the threshold voltage of the driving element TD due to degradation.

[0063] Because the third switching element TS3 is turned on, the compensation circuit 200 can sense the driving current Id through the Mth sensing line L_senm. The compensation circuit 200 can generate a first sensing voltage VS1 corresponding to the driving current Id using the sensing resistor Rsen. The compensation circuit 200 can output the first sensing voltage VS1 as a second sensing voltage VS2 using an amplifier AMP. The amplifier AMP can output the second sensing voltage VS2 by amplifying the first sensing voltage VS1 and removing noise. The compensation circuit 200 can compare the data voltage Vdata1 with the second sensing voltage VS2, and output a compensated data voltage Vdata2 that compensates for the threshold voltage of the driving element TD.

[0064] The compensation circuit 200 may continuously provide the compensation data voltage Vdata2 during the emission period P2. The first scan signal SCAN1 and the second scan signal SCAN2 having a low level and the third scan signal SCAN3 having a high level may be provided to the pixel PX during the emission period P2. The first switching element TS1 may be turned on in response to the first scan signal SCAN1, the second switching element TS2 may be turned on in response to the second scan signal SCAN2, the third switching element TS3 may be turned off in response to the third scan signal SCAN3, and the compensation data voltage Vdata2 is maintained.

[0065] Because the first switching element TS1 is turned on, the compensation data voltage Vdata2 can be provided to the first node N1 through the Mth data line DLm coupled to the output terminal OUT of the comparator COM. The driving element TD can generate a driving current Id corresponding to the voltage of the first node N1. Because the second switching element TS2 is turned on, the organic light emitting diode EL can emit light based on the driving current Id.

[0066] Despite Figure 4 , wherein the compensation period P1 and the emission period P2 are sequentially arranged, but the timing diagram of the pixel PX is not limited thereto. For example, the timing diagram also includes an initialization period (during which the driving element TD and the organic light emitting diode EL are initialized) and a data writing period (during which the data voltage Vdata1 is written into the storage capacitor CST) arranged between the compensation period P1 and the emission period P2, etc. In addition, the compensation period P1 may be repeated in a cycle (e.g., a predetermined cycle).

[0067] Reference Figure 5 , the compensation circuit 200 may sense the driving current Id of the pixel PX during the compensation period P1. The first scan signal SCAN1 and the third scan signal SCAN3 having a low level and the second scan signal SCAN2 having a high level may be provided to the pixel PX during the compensation period P1. The first switching element TS1 may be turned on in response to the first scan signal SCAN1, the third switching element TS3 may be turned on in response to the third scan signal SCAN3, and the second switching element TS2 may be turned off in response to the second scan signal SCAN2.

[0068] Because the first switching element TS1 is turned on, the data voltage Vdata1 provided through the Mth data line DLm may be provided to the first node N1. The driving element TD may generate a driving current Id corresponding to the voltage of the first node N1. Here, the driving current Id may be reduced by a change in the threshold voltage of the driving element TD due to degradation. Because the third switching element TS3 is turned on, the compensation circuit 200 may sense the driving current Id through the Mth sensing line L_senm. The compensation circuit 200 may generate a first sensing voltage VS1 corresponding to the driving current Id using a sensing resistor Rsen. The compensation circuit 200 may output the first sensing voltage VS1 as a second sensing voltage VS2 using an amplifier AMP. The compensation circuit 200 may compare the data voltage Vdata1 with the second sensing voltage VS2, and output a compensation data voltage Vdata2 that compensates for the threshold voltage of the driving element TD. The compensation data voltage Vdata2 may be provided to the pixel PX through the Mth data line DLm. Since the first switching element TS1 is turned on during the compensation period P1 , the compensated data voltage Vdata2 may be provided to the first node N1 and stored in the storage capacitor CST.

[0069] A second scan signal SCAN2 having a low level, a first scan signal SCAN1 having a high level, and a third scan signal SCAN3 may be provided to the pixel PX during the emission period P2. The second switching element TS2 may be turned on in response to the second scan signal SCAN2, the first switching element TS1 may be turned off in response to the first scan signal SCAN1, and the third switching element TS3 may be turned off in response to the third scan signal SCAN3. The driving element TD may generate a driving current Id corresponding to the voltage stored in the storage capacitor CST. Since the second switching element TS2 is turned on, the organic light emitting diode EL may emit light based on the driving current Id.

[0070] Despite Figure 5 , wherein the compensation period P1 and the emission period P2 are sequentially arranged, but the timing diagram of the pixel PX is not limited thereto. For example, the timing diagram also includes an initialization period (during which the driving element TD and the organic light emitting diode EL are initialized), a data writing period (during which the data voltage Vdata1 is written into the storage capacitor CST), etc. arranged between the compensation period P1 and the emission period P2. In addition, the compensation period P1 may be repeated in a cycle (e.g., a predetermined cycle).

[0071] Figure 6 It is shown Figure 2 A circuit diagram of an example of a compensation circuit and a pixel.

[0072] Reference Figure 6, the compensation circuit 300 may be coupled to the pixel PX. Figure 6 The compensation circuit 300 can be used with Figure 1 and Figure 2 The compensation circuit 150 corresponds to. Figure 6 The compensation circuit 300 described in can be coupled to the M-th data line DLm and the M-th sensing line L_senm. Figure 6 The pixel PX described in may be one of the pixels coupled to the Mth data line DLm and the Mth sensing line L_senm.

[0073] Reference Figure 6 , the pixel PX may include a driving element TD, a first switching element TS1, a second switching element TS2, a storage capacitor CST, and an organic light emitting diode EL. For example, the driving element TD, the first switching element TS1, and the second switching element TS2 may be PMOS transistors.

[0074] The driving element TD may include a gate electrode, a first electrode, and a second electrode. The driving element TD may include a gate electrode coupled to the first node N1, a first electrode receiving a first power voltage ELVDD, and a second electrode coupled to an anode electrode of the organic light emitting diode EL. For example, the first power voltage ELVDD may be a high power voltage. The driving element TD may generate a driving current Id corresponding to a voltage applied to the first node N1.

[0075] The first switching element TS1 may include a gate electrode receiving a first scan signal SCAN1, a first electrode coupled to an Mth data line DLm, and a second electrode coupled to a first node N1. When the first switching element TS1 is a PMOS transistor, the first switching element TS1 may be turned on in response to the first scan signal SCAN1 having a low level. When the first switching element TS1 is turned on, the compensation data voltage Vdata2 provided through the Mth data line DLm may be provided to the first node N1.

[0076] The second switching element TS2 may include a gate electrode receiving a second scan signal SCAN2, a first electrode coupled to a cathode electrode of the organic light emitting diode EL, and a second electrode coupled to the compensation circuit 300. When the second switching element TS2 is a PMOS transistor, the second switching element TS2 may be turned on in response to the second scan signal SCAN2 having a low level. When the second switching element TS2 is turned on during the emission period, the driving current Id flowing through the organic light emitting diode EL may be provided to the compensation circuit 300 through the second switching element TS2 and the Mth sensing line L_senm.

[0077] Despite Figure 6, a pixel PX including a driving element TD, a first switching element TS1, and a second switching element TS2 implemented as PMOS transistors is described, but the driving element TD, the first switching element TS1, and the second switching element TS2 are not limited thereto. For example, the driving element TD, the first switching element TS1, and the second switching element TS2 may be implemented as N-channel metal oxide semiconductor (NMOS) transistors.

[0078] The compensation circuit 300 may include a sensing unit 320 and a compensation data voltage generator 340 . Figure 6 The sensing unit 320 and the compensated data voltage generator 340 may be connected with Figure 2 The sensing unit 320 corresponds to the sensing unit 152 and the compensation data voltage generator 154. The sensing unit 320 may include a sensing resistor Rsen and an amplifier AMP. The sensing resistor Rsen may generate a first sensing voltage VS1 corresponding to the driving current Id provided through the Mth sensing line L_senm. The amplifier AMP may output a second sensing voltage VS2 by amplifying the first sensing voltage VS1 generated by the sensing resistor Rsen.

[0079] The second sensing voltage VS2 may be provided to the compensated data voltage generator 340. The compensated data voltage generator 340 may include a comparator COM. The comparator COM may compare the data voltage Vdata1 with the second sensing voltage VS2 and convert the data voltage Vdata1 into the compensated data voltage Vdata2. The comparator COM may include a first input terminal IN1 receiving the data voltage Vdata1, a second input terminal IN2 receiving the second sensing voltage VS2, and an output terminal OUT outputting the compensated data voltage Vdata2 by comparing the data voltage Vdata1 with the second sensing voltage VS2.

[0080] The second sensing voltage VS2 may be a voltage corresponding to a reduced driving current Id generated by a driving element TD whose threshold voltage changes due to degradation. The comparator COM may output a compensated data voltage Vdata2 that compensates for a difference between a data voltage Vdata1 provided from the data driver 140 and a second sensing voltage VS2 provided from the sensing unit 320. That is, the compensated data voltage Vdata2 may have a voltage level that compensates for the reduced driving current Id due to a change in the threshold voltage of the driving element TD. The output terminal OUT of the comparator COM may be coupled to the Mth data line DLm and provide the compensated data voltage Vdata2 to the first electrode of the first switching element TS1 included in the pixel PX. Although in Figure 6, the compensated data voltage generator 340 including the comparator COM is described, but the compensated data voltage generator 340 may not be limited thereto. For example, the compensated data voltage generator 340 may further include a calculator that calculates a difference between the data voltage Vdata1 and the second sensing voltage VS2.

[0081] Figure 7 is a block diagram illustrating an electronic device according to some example embodiments. Figure 8 It shows that Figure 7 FIG. 1 is a diagram of an example embodiment in which the electronic device is implemented as a smart phone.

[0082] Reference Figure 7 and Figure 8 , the electronic device 400 may include a processor 410, a memory device 420, a storage device 430, an input / output (I / O) device 440, a power supply 450, and a display device 460. Here, the display device 460 may be connected to Figure 1 In addition, the electronic device 400 may further 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, etc. Figure 8 4 shows that the electronic device 400 is implemented as a smart phone 500 , but the kind of the electronic device 400 is not limited thereto.

[0083] The processor 410 may perform various computing functions. The processor 410 may be a microprocessor, a central processing unit (CPU), etc. The processor 410 may be coupled to other components via an address bus, a control bus, a data bus, etc. In addition, the processor 410 may be coupled to an expansion bus such as a peripheral component interconnect (PCI) bus. The memory device 420 may store data for the operation of the electronic device 400. For example, the memory device 420 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 resistance 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 DRAM device, etc.). The storage device 430 may be a solid state drive (SSD) device, a hard disk drive (HDD) device, a CD-ROM device, or the like.

[0084] The I / O device 440 may be an input device such as a keyboard, a keypad, a touch pad, a touch screen, a mouse, etc., and an output device such as a printer, a speaker, etc. In some example embodiments, a display device 460 may be included in the I / O device 440. The power supply 450 may provide power for the operation of the electronic device 400. The display device 460 may communicate with other components via a bus or other communication links. As described above, the display device 460 may include a display panel, a timing controller, a scan driver, a data driver, and a compensation circuit.

[0085] The display panel may include a plurality of pixels including an organic light emitting diode and a driving element. The display panel may include a plurality of scan lines and a plurality of data lines. Each pixel may be electrically coupled to the scan line and the data line. In some example embodiments, a first scan line and a second scan line may be formed in the display panel. In other example embodiments, a first scan line, a second scan line, and a third scan line may be formed in the display panel. The timing controller may convert first image data provided from an external device into second image data.

[0086] The timing controller may generate a data control signal and a scan control signal for controlling the driving of the second image data based on a control signal provided from an external device. The scan driver may provide a scan signal to a pixel through a scan line. For example, the scan driver may generate a first scan signal provided to a pixel through a first scan line and a second scan signal provided to a pixel through a second scan line. The scan driver may also generate a third scan signal provided to a pixel through a third scan line. The data driver may generate a data voltage based on the second image data and the data control signal. The compensation circuit may sense a driving current flowing through a pixel and generate a compensation data voltage for compensating a threshold voltage of a driving element based on the data voltage and the driving current. The compensation circuit may be coupled to the data line and the sensing line, respectively.

[0087] In some example embodiments, the pixel may include a driving element, a first switching element, a second switching element, a third switching element, a storage capacitor, and an organic light emitting diode. Each compensation circuit may include a sensing unit and a compensation data voltage generator. The sensing unit may sense the driving current of the pixel through a sensing line and generate a sensing voltage corresponding to the driving current. For example, the sensing unit may include a sensing resistor and an amplifier. The sensing resistor may generate a first sensing voltage corresponding to the driving current provided by the third switching element and the sensing line of the pixel. The amplifier may generate a second sensing voltage by amplifying the first sensing voltage generated by the sensing resistor. The second sensing voltage may be provided to the compensation data voltage generator. The compensation data voltage generator may generate a compensation data voltage that compensates for the threshold voltage of the driving element based on the data voltage and the second sensing voltage. For example, the compensation data voltage generator may include a comparator. The comparator may compare the data voltage with the second sensing voltage and convert the data voltage into the compensation data voltage.

[0088] In other example embodiments, the pixel may include a driving element, a first switching element, a second switching element, a storage capacitor, and an organic light emitting diode. Each compensation circuit may include a sensing unit and a compensation data voltage generator. The sensing unit may sense the driving current of the pixel through a sensing line and generate a sensing voltage corresponding to the driving current. For example, the sensing unit may include a sensing resistor and an amplifier.

[0089] The sensing resistor may generate a first sensing voltage corresponding to a driving current provided by a second switching element and a sensing line of the pixel. The amplifier may generate a second sensing voltage by amplifying the first sensing voltage generated by the sensing resistor. The second sensing voltage may be provided to a compensation data voltage generator. The compensation data voltage generator may generate a compensation data voltage that compensates for a threshold voltage of a driving element based on the data voltage and the second sensing voltage. For example, the compensation data voltage generator may include a comparator. The comparator may compare the data voltage with the second sensing voltage and convert the data voltage into a compensation data voltage.

[0090] As described above, the electronic device 400 according to some example embodiments may include a display device 460 that senses a driving current of a pixel and generates a compensation data voltage that compensates for a change in the driving current due to a change in a threshold voltage of a driving element based on the driving current. Therefore, the display quality of the display device 460 may be improved.

[0091] The inventive concept can be applied to a display device and an electronic device having the display device. For example, the inventive concept can be applied to a computer monitor, a laptop computer, a digital camera, a cellular phone, a smart phone, a smart tablet, a television, a personal digital assistant (PDA), a portable multimedia player (PMP), an MP3 player, a navigation system, a game console, a video phone, etc.

[0092] The foregoing is an illustration of aspects of some example embodiments and will not be construed as limiting aspects of these embodiments. Although some example embodiments have been described, it will be readily appreciated by those skilled in the art that many modifications are possible in the example embodiments without substantially departing from the novel teachings and advantages of the inventive concept. Therefore, all such modifications are intended to be included within the scope of the inventive concept as defined in the claims and their equivalents. Therefore, it will be understood that the foregoing is an illustration of various example embodiments and will not be construed as being limited to the specific example embodiments disclosed, and modifications to the disclosed example embodiments as well as other example embodiments are intended to be included within the scope of the claims and their equivalents.

Claims

1. A display device, comprising: A display panel including a plurality of pixels, each of the pixels including an organic light emitting diode and a driving element, the display panel being configured to display image data on the pixels; a data driver configured to generate a data voltage corresponding to the image data; a compensation circuit configured to sense a driving current flowing through the pixel and generate a compensation data voltage that compensates for a threshold voltage of the driving element based on the data voltage and the driving current; a scan driver configured to generate a first scan signal and a second scan signal provided to the pixel; as well as a timing controller configured to generate a control signal for controlling the data driver and a control signal for controlling the scan driver, Wherein, the compensation circuit comprises: a sensing unit configured to sense the driving current and generate a sensing voltage corresponding to the driving current; and A compensation voltage generator is configured to generate the compensation data voltage compensating for the threshold voltage of the driving element based on the data voltage and the sensing voltage.

2. The display device according to claim 1, wherein: The sensing unit comprises: a sensing resistor configured to sense the driving current and generate a first sensing voltage corresponding to the driving current; and An amplifier is configured to output a second sensing voltage by amplifying the first sensing voltage.

3. The display device according to claim 2, wherein: The compensation voltage generator includes a comparator that compares the data voltage with the second sensing voltage and converts the data voltage into the compensated data voltage.

4. The display device according to claim 3, wherein: The comparator comprises: A first input terminal configured to receive the data voltage; a second input terminal configured to receive the second sensing voltage; and An output terminal is configured to output the compensated data voltage by comparing the data voltage with the second sensing voltage.

5. The display device according to claim 1, wherein: The organic light emitting diode comprises an anode electrode and a cathode electrode, and The driving element includes a gate electrode coupled to a first node, a first electrode receiving a first power voltage, and a second electrode.

6. The display device according to claim 5, wherein: The scan driver is further configured to generate a third scan signal provided to the pixel.

7. The display device according to claim 6, wherein: The second electrode of the driving element is coupled to a second node, and Wherein, each of the pixels further comprises: The first switching element includes: a gate electrode configured to receive the first scan signal; a first electrode coupled to the compensation voltage generator; and a second electrode coupled to the first node; A second switching element includes: a gate electrode configured to receive the second scan signal; a first electrode coupled to the second node; and a second electrode coupled to the anode electrode of the organic light emitting diode; A third switching element includes: a gate electrode configured to receive the third scan signal; a first electrode coupled to the second node; and a second electrode coupled to the sensing unit; and A storage capacitor includes: a first electrode configured to receive the first power voltage; and a second electrode coupled to the first node.

8. The display device according to claim 7, wherein: In a compensation period of the pixel, the first switching element and the third switching element are configured to be turned on, and the second switching element is configured to be turned off.

9. The display device according to claim 7, wherein: In an emission period of a pixel, the first switching element and the second switching element are configured to be turned on, the third switching element is configured to be turned off, and the compensation data voltage is maintained.

10. The display device according to claim 7, wherein: In an emission period of the pixel, the second switching element is configured to be turned on, and the first switching element and the third switching element are configured to be turned off.

11. The display device according to claim 5, wherein: The second electrode of the driving element is coupled to the anode electrode of the organic light emitting diode, and Wherein, each of the pixels further comprises: The first switching element includes: a gate electrode configured to receive the first scan signal; a first electrode coupled to the compensation voltage generator; and a second electrode coupled to the first node; a second switching element including: a gate electrode configured to receive the second scanning signal; a first electrode coupled to the cathode electrode of the organic light emitting diode; and a second electrode coupled to the sensing unit; and A storage capacitor includes: a first electrode configured to receive the first power voltage; and a second electrode coupled to the first node.

12. The display device according to claim 11, wherein: In an emission period of the pixel, the second switching element is configured to be turned on, and the drive current is sensed.

13. The display device according to claim 1, wherein: The compensation circuit is located in or incorporated into the data driver.

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