Display device and driving method of display device

Abstract

A display device and a driving method of a display device are provided. The display device includes a display unit, a timing controller, a data driver, and a sensing unit. The display unit includes data lines, sensing lines, and pixels including light emitting elements and first transistors for providing driving current to the light emitting elements. The timing controller generates a first voltage value by compensating for a first gray value, and generates a second voltage value by re-mapping the first voltage value from a first voltage range to a second voltage range. The data driver generates a data voltage based on the second voltage value and supplies the data voltage to the data lines. The sensing unit provides an initialization voltage to the sensing lines. A voltage difference between the data voltage and a threshold voltage of the transistor is greater than or equal to the initialization voltage.

Description

[0001] Cross-references to related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2019-0136731, filed on October 30, 2019, which is incorporated herein by reference in its entirety. Technical Field

[0003] Embodiments of this disclosure relate to a display device and a method for driving the display device. Background Technology

[0004] The display device includes a display panel and a driving unit. The display panel includes multiple scan lines, multiple data lines, and multiple pixels. The driving unit includes a scan driver and a data driver, wherein the scan driver sequentially provides scan signals to the scan lines, and the data driver provides data signals to the data lines. Each of the multiple pixels can emit light with a brightness corresponding to the data signal provided through the corresponding data line in response to the scan signal provided through the corresponding scan line.

[0005] The display device displays an image through a plurality of pixels, and each of the plurality of pixels may include a light-emitting element and a driving transistor for supplying driving current to the light-emitting element.

[0006] The light-emitting characteristics of pixels may vary due to variations in the manufacturing process. Display devices can compensate for data signals or corresponding grayscale values ​​by using bias values ​​that can be set in the manufacturing process, so that the pixels of the display device can emit light uniformly.

[0007] Light-emitting elements, including organic light-emitting diodes (OLEDs), may degrade over time. Display devices can employ degradation compensation techniques to compensate for data signals (or grayscale values). Accordingly, display devices can prevent, mitigate, and / or compensate for the degradation of light-emitting elements.

[0008] In addition, the display device may use external compensation techniques to compensate for changes in the light emission characteristics of each pixel based on the threshold voltage information and / or mobility information sensed by the driving transistor of the pixel or the degradation information of the light-emitting element of the pixel. Summary of the Invention

[0009] In a display device employing both a deterioration compensation technique and an external compensation technique, an external compensation value of a compensation value of a data signal obtained through the external compensation technique can be offset by a deterioration compensation value. As a result, a pixel can not emit light at a desired luminance. Especially, in a low gray scale range sensitive to a change in a light emitting characteristic (e.g., a gray scale-voltage characteristic) of a pixel (e.g., in a low gray scale range corresponding to a relatively small gray scale value), a light emitting characteristic of a pixel compensated through the compensation technique can greatly deviate from a light emitting characteristic of a normal pixel, and linearity of the light emitting characteristic of the pixel can deteriorate or be lost.

[0010] The present disclosure provides a display device and a driving method of a display device capable of preventing a compensation of an external compensation technique from deteriorating due to a deterioration compensation technique and obtaining linearity of a light emitting characteristic of a pixel in a low gray scale range.

[0011] A display device according to an embodiment of the present disclosure can include a display unit, a timing controller, a data driver, and a sensing unit, wherein the display unit includes data lines, sensing lines, and pixels connected with the data lines and the sensing lines, the pixels include light emitting elements and first transistors for providing driving currents to the light emitting elements, the timing controller generates first voltage values by compensating for first gray scale values and generates second voltage values by re-mapping the first voltage values, the data driver generates data voltages based on the second voltage values in a display period and supplies the data voltages to the data lines, and the sensing unit provides an initialization voltage to the sensing lines in the display period and senses threshold voltages of the first transistors through the sensing lines in a sensing period. The timing controller can re-map the first voltage values in a first voltage range to the second voltage values in a second voltage range such that a voltage difference between the data voltages and the threshold voltages of the first transistors is greater than or equal to the initialization voltage.

[0012] According to an embodiment, the second voltage range can be a subset of the first voltage range.

[0013] According to an embodiment, a minimum voltage value of the second voltage range can be greater than a minimum voltage value of the first voltage range, and a maximum voltage value of the second voltage range can be equal to a maximum voltage value of the first voltage range.

[0014] According to an embodiment, a voltage greater than or equal to zero can be applied between a gate electrode and a source electrode of the first transistor according to the data voltage.

[0015] According to an embodiment, for a first gray scale value that is a minimum gray scale value corresponding to black, a voltage difference between the data voltage for the first gray scale value and the threshold voltage of the first transistor can be equal to the initialization voltage.

[0016] According to an embodiment, the pixel can include a second transistor connected between the data line and the first node, a storage capacitor connected between the first node and a second node, and a third transistor connected between the second node and the sensing line. One electrode of the light emitting element can be connected to the second node. The first transistor can provide a driving current to the second node in response to a voltage of the first node.

[0017] According to an embodiment, the first transistor can include an oxide semiconductor.

[0018] According to an embodiment, the timing controller can include a first compensation circuit, a second compensation circuit, a third compensation circuit, and a fourth compensation circuit, wherein the first compensation circuit converts a first gray value into a first gray voltage value according to a reference gamma curve, the second compensation circuit calculates a first voltage value by adding the first gray voltage value and a compensation value, the third compensation circuit calculates a second voltage value by remapping the first voltage value from a first voltage range to a second voltage range, and the fourth compensation circuit outputs the second voltage value by compensating the second voltage value based on a threshold voltage of the first transistor. The compensation value can be preset based on a characteristic deviation of the pixel, or can be calculated based on a deterioration level of the pixel.

[0019] According to an embodiment, the compensation value can be less than zero, and the first voltage value can be less than the first gray level voltage value.

[0020] According to an embodiment, the third compensation circuit can scale the first voltage value, and shift the scaled first voltage value into the second voltage range.

[0021] According to an embodiment, the third compensation circuit can map a minimum voltage value of the first voltage range to a voltage value corresponding to a sum of an initialization voltage and a threshold voltage of the first transistor.

[0022] According to an embodiment, for the first voltage value being less than the sum of the initialization voltage and the threshold voltage of the first transistor, the third compensation circuit can map the first voltage value to a voltage value corresponding to the sum of the initialization voltage and the threshold voltage of the first transistor.

[0023] According to an embodiment, the third compensation circuit can remap the first voltage value to the second voltage value using a look-up table.

[0024] According to one embodiment, a display device according to embodiments of the present disclosure may include a display unit, a timing controller, a data driver, and a sensing unit. The display unit includes data lines, sensing lines, and pixels connected to the data lines and sensing lines. Each pixel includes a light-emitting element and a transistor for providing driving current to the light-emitting element. The timing controller generates a first voltage value by compensating for a first grayscale value and generates a second voltage value by remapping the first voltage value. The data driver generates a data voltage based on the second voltage value and supplies the data voltage to the data lines. The sensing unit provides an initialization voltage to the sensing lines. The timing controller can remap a first voltage value within a first voltage range to a second voltage value within a second voltage range, such that the voltage difference between the data voltage and the threshold voltage of the transistor is greater than or equal to the initialization voltage.

[0025] According to one embodiment, a method according to an embodiment of the present disclosure can drive a display device including data lines, sensing lines, and pixels connected to the data lines and sensing lines, wherein the pixel includes a light-emitting element and a transistor for providing driving current to the light-emitting element. The method may include: converting a first grayscale value of the pixel into a first grayscale voltage value based on a reference gamma curve; calculating a first voltage value by adding the first grayscale voltage value and a compensation value; calculating a second voltage value by remapping the first voltage value from a first voltage range to a second voltage range; generating a compensated second voltage value by compensating the second voltage value based on a threshold voltage of the transistor; and providing an initialization voltage to the pixel via the sensing lines and providing a data voltage generated based on the compensated second voltage value to the pixel via the data lines. The compensation value may be preset based on a characteristic deviation of the pixel or calculated based on a degradation level of the pixel. Calculating the second voltage value may include: remapping the first voltage value to the second voltage value such that the voltage difference between the data voltage and the threshold voltage of the first transistor is greater than or equal to the initialization voltage. Attached Figure Description

[0026] The accompanying drawings are included to provide a further understanding of the inventive concept and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the inventive concept and, together with the description, serve to explain the principles of the inventive concept.

[0027] Figure 1 This is a block diagram illustrating a display device according to an embodiment of the present disclosure.

[0028] Figure 2 It is shown that it includes Figure 1 A circuit diagram of an example of a pixel in a display device.

[0029] Figure 3 It is shown in Figure 2 A waveform diagram of an instance of a signal measured in a pixel.

[0030] Figure 4 is a graph showing a voltage-current characteristic of a first transistor included in a pixel of Figure 2

[0031] Figure 5 is a block diagram showing an example of a timing controller included in a display device of Figure 1

[0032] Figure 6A Figure 6B Figure 6C and Figure 6D Figure 5 are graphs showing examples of a gray voltage characteristic of a pixel compensated for by a timing controller of

[0033] Figure 7 is a flowchart showing an example of performing gray voltage compensation according to an embodiment of the disclosure. DETAILED DESCRIPTION

[0034] The disclosure can be modified in various ways and can have various forms and configurations, and specific embodiments will be shown in the accompanying drawings and described in detail herein. However, the disclosure is not limited to the embodiments disclosed herein, and can be modified and implemented in various different forms and configurations.

[0035] In the drawings, some components that are not directly related to the features of the disclosure can be omitted to clearly show the disclosure. In addition, some components in the drawings can be shown as being enlarged in size, ratio, etc. Throughout the drawings, even if the same or similar components can be shown in different drawings, they are represented by the same reference numerals and symbols, and the repeated description will be omitted.

[0036] Figure 1 is a block diagram showing a display device according to an embodiment of the disclosure.

[0037] Referring to Figure 1 , the display device 100 can include a display unit (or display panel) 110, a scan driver (or gate driver) 120, a data driver (or source driver) 130, a timing controller 140, and a sensing unit (or sensing circuit) 150.

[0038] The display unit 110 can include scan lines SL1 to SLi, data lines DL1 to DLj, and pixels PX, where i and j are positive integers. In addition, the display unit 110 can further include sensing control lines SSL1 to SSLi and sensing lines (or lead-out lines) RL1 to RLj.

[0039] ​​​​​The pixels PX can be disposed in regions (e.g., pixel regions) divided by the scan lines SL1 to SLi and the data lines DL1 to DLj.

[0040] Each of the pixels PX can be electrically connected to one of the scan lines SL1 to SLi and one of the data lines DL1 to DLj. Also, each of the pixels PX can be electrically connected to one of the sensing control lines SSL1 to SSLi and one of the sensing lines RL1 to RLj. Each of the pixels PX can include a light emitting element and at least one transistor for providing a driving current to the light emitting element.

[0041] The pixels PX can emit light with luminance corresponding to a data voltage (or a data signal) provided through the data lines in response to a scan signal provided through the scan lines. Also, the pixels PX can output characteristic information (or deterioration information, e.g., a sensing voltage or a sensing current) of the light emitting element through the sensing lines in response to a sensing control signal provided through the sensing control lines.

[0042] A detailed configuration and operation of the pixels PX will be described later with reference to Figure 2 A detailed configuration and operation of the pixels PX will be described later with reference to

[0043] The display unit 110 can be provided with a first power voltage VDD and a second power voltage VSS. The first power voltage VDD and the second power voltage VSS are used to operate the pixels PX. The first power voltage VDD can have a voltage level higher than that of the second power voltage VSS. The first power voltage VDD and the second power voltage VSS can be provided to the display unit 110 from an external power supply unit.

[0044] The scan driver 120 can generate scan signals based on a scan control signal SCS and sequentially provide the scan signals to the scan lines SL1 to SLi. Here, the scan control signal SCS can include a start signal (or a start pulse), a clock signal, and the like, and can be provided from the timing controller 140. For example, the scan driver 120 can include a shift register (or stage) that sequentially generates and outputs a scan signal having a pulse form corresponding to a start signal having a pulse form using a clock signal.

[0045] Similarly to the scan signals, the scan driver 120 can also generate sensing control signals and provide the sensing control signals to the sensing control lines SSL1 to SSLi.

[0046] The data driver 130 can generate a data voltage (or a data signal) based on the image data DATA2 (or compensated gray scale values) and a data control signal DCS provided from the timing controller 140, and provide the data voltage to the data lines DL1 to DLj. Here, the data control signal DCS is a signal for controlling the operation of the data driver 130, and can include a load signal (or a data strobe signal) indicating the output of the effective data voltage.

[0047] In an embodiment, the data driver 130 can generate a data voltage corresponding to a data value (a gray scale value or a digital voltage value) included in the image data DATA2 using a gamma voltage. Here, the gamma voltage can be generated by the data driver 130, or can be provided from a separate gamma voltage generation circuit (e.g., a gamma integrated circuit). The data driver 130 can select one of the gamma voltages based on the data value, and output the same as the data voltage.

[0048] The sensing unit 150 can provide an initialization voltage to the sensing lines RL1 to RLj in a display period, and can sense the emission characteristics of the pixels PX through the sensing lines RL1 to RLj in a sensing period. Here, the display period can correspond to a period in which the data voltage is provided or written to the pixels PX and the pixels PX emit light, and the sensing period can correspond to a period allocated to sense the emission characteristics of the pixels PX before or after the display period. The display period and the sensing period can be included in one frame (or a frame period). The emission characteristics of the pixels PX can include the threshold voltage and mobility of at least one transistor (e.g., a driving transistor) in the pixels PX and characteristic information (e.g., a degree of deterioration) of the emission element. For example, the sensing unit 150 can detect a sensing value (e.g., a sensing voltage or a sensing current) corresponding to the emission characteristics of the pixels PX through the sensing lines RL1 to RLj.

[0049] The sensing value can be provided to the timing controller 140, and the timing controller 140 can compensate the image data DATA2 (or the input image data DATA1) based on the sensing value. However, the present disclosure is not limited thereto. For example, the sensing unit 150 can provide the sensing value to the data driver 130, and the data driver 130 can generate a data voltage based on the sensing value. In this case, the data driver 130 can change or compensate the data voltage based on the amount of change in the sensing value. The data voltage can be compensated based on the emission characteristics (or changes in the emission characteristics) of the corresponding pixels PX.

[0050] The timing controller 140 can receive input image data DATA1 and a control signal CS from an external device (e.g., a graphic processor), generate a scan control signal SCS and a data control signal DCS based on the control signal CS, and convert the input image data DATA1 to generate image data DATA2. Here, the control signal CS can include a vertical synchronization signal, a horizontal synchronization signal, a clock signal, and the like. For example, the timing controller 140 can convert the input image data DATA1 to the image data DATA2 having a format that can be utilized by the data driver 130.

[0051] In addition, the timing controller 140 can generate a compensation control signal CCS based on the control signal CS. The compensation control signal CCS can be provided to the sensing unit 150.

[0052] In an embodiment, the timing controller 140 can convert a first gray scale value included in the input image data DATA1 to a first voltage value based on a degradation compensation technique and an external compensation technique. Here, the first voltage value can correspond to a data value representing a data voltage corresponding to the first gray scale value.

[0053] In an embodiment, the timing controller 140 can map (or re-map) the first voltage value from a first voltage range (or a first gray scale voltage range) to a second voltage range (or a second gray scale voltage range) such that a voltage difference between a data voltage and a threshold voltage of a driving transistor included in the pixel PX is greater than or equal to an initialization voltage. Here, the threshold voltage of the driving transistor can be sensed by the sensing unit 150 in a sensing period, and the initialization voltage can be provided to the pixel PX by the sensing unit 150 in a display period. The second voltage range can be a subset of the first voltage range. A minimum voltage value of the second voltage range can be greater than a minimum voltage value of the first voltage range, and a maximum voltage value of the second voltage range can be equal to a maximum voltage value of the first voltage range.

[0054] For example, a voltage difference between a data voltage corresponding to a minimum gray scale value (e.g., a gray scale value corresponding to black or a gray scale value of 0) and a threshold voltage of a driving transistor can be equal to an initialization voltage.

[0055] For reference, the degradation compensation technique compensates for a change in the light emitting characteristics of the pixel PX by using a lookup table including a fixed gain and offset, and the external compensation technique compensates for a change in the light emitting characteristics of the pixel PX by using a value actually sensed by the sensing unit 150. According to an embodiment of the disclosure, the display device 100 can sequentially compensate for the voltage value (or the gray value) using the degradation compensation technique and the external compensation technique. In addition, in order for the data voltage to be normally compensated for by the external compensation technique, the display device 100 can remap the compensated voltage value to a reference voltage range (i.e., a voltage range corresponding to a case where the voltage difference between the data voltage and the threshold voltage of the driving transistor is greater than or equal to the initialization voltage) by the degradation compensation technique. For example, the display device 100 can remap the minimum voltage value compensated for by the degradation compensation technique to the sum of the threshold voltage of the driving transistor and the initialization voltage (i.e., the total voltage). In this case, the gray value in the low gray range can be accurately compensated for by the external compensation technique, and the linearity of the light emitting characteristics of the pixel PX in the low gray range can be obtained.

[0056] As described with reference to Figure 1 , the display device 100 (or the timing controller 140) can generate the first voltage value by sequentially compensating for the gray value using the degradation compensation technique and the external compensation technique. In addition, the display device 100 can remap the first voltage value in the first voltage range to the second voltage value in the second voltage range so that the voltage difference between the data voltage and the threshold voltage of the driving transistor is greater than or equal to the initialization voltage before the first voltage value is compensated for using the external compensation technique. Accordingly, compensation for a change in the light emitting characteristics of the pixel PX by the external compensation technique can be maintained, and the linearity of the light emitting characteristics of the pixel PX in the low gray range can be obtained.

[0057] At least one of the scan driver 120, the data driver 130, the timing controller 140, and the sensing unit 150 can be formed on the display unit 110, or can be implemented as an integrated circuit (IC) and mounted on a flexible circuit board and connected to the display unit 110. In addition, at least two of the scan driver 120, the data driver 130, the timing controller 140, and the sensing unit 150 can be implemented as a single IC.

[0058] Figure 2 is a circuit diagram illustrating an example of the pixel PX included in the display device 100 of Figure 1 .

[0059] Referring to Figure 2 , the pixel PX can be connected to an n-th scan line SLn, a k-th data line DLk, an n-th sensing control line SSLn, and a k-th sensing line RLk (where n and k are positive integers).

[0060] The pixel PX can include a light emitting element LED, a first transistor (also referred to as a driver transistor herein) T1, a second transistor (also referred to as a switch transistor herein) T2, a third transistor (also referred to as a sensing transistor herein) T3, and a storage capacitor Cst. Each of the first transistor T1, the second transistor T2, and the third transistor T3 can be a thin film transistor including an oxide semiconductor.

[0061] The anode of the light emitting element LED can be connected to the second node N2 (or the second electrode of the first transistor T1), and the cathode of the light emitting element LED can be connected to a second power supply line to which a second power supply voltage VSS is applied. The light emitting element LED can generate light with a predetermined luminance in response to an amount of current (or driving current) supplied from the first transistor T1. The light emitting element LED can be an organic light emitting diode, but the present disclosure is not limited thereto. For example, the light emitting element LED can include an inorganic light emitting diode.

[0062] The first electrode of the first transistor T1 can be connected to a first power supply line to which a first power supply voltage VDD is applied, and the second electrode of the first transistor T1 can be connected to the second node N2 (or the anode of the light emitting element LED). The gate electrode of the first transistor T1 can be connected to the first node N1. The first transistor T1 can control the amount of current flowing to the light emitting element LED in response to the voltage of the first node N1.

[0063] The first electrode of the second transistor T2 can be connected to the kth data line DLk, and the second electrode of the second transistor T2 can be connected to the first node N1. The gate electrode of the second transistor T2 can be connected to the nth scan line SLn. When a scan signal S[n] is supplied to the nth scan line SLn, the second transistor T2 can be turned on, thereby transmitting a data voltage DATA (or a data signal) from the kth data line DLk to the first node N1.

[0064] The storage capacitor Cst can be connected between the first node N1 and the anode of the light emitting element LED. The storage capacitor Cst can store the voltage of the first node N1.

[0065] The third transistor T3 can be connected between the kth sensing line RLk and the second node N2 (or the second electrode of the first transistor T1). The third transistor T3 can connect the second node N2 and the kth sensing line RLk in response to a sensing control signal SEN[n] supplied to the nth sensing control line SSLn. A sensing voltage (or a node voltage of the second node N2) can be supplied to the kth sensing line RLk through the third transistor T3 based on the sensing control signal SEN[n]. However, the present disclosure is not limited thereto. For example, a sensing current corresponding to the node voltage of the second node N2 can be transmitted to the kth sensing line RLk. In this embodiment, the sensing voltage can be supplied to the sensing unit 150 through the kth sensing line RLk (refer to Figure 1 ).

[0066] In the embodiments of the present disclosure, the pixel PX is not limited to the circuit structure shown in Figure 2 , and the pixel PX can have various other circuit structures without departing from the scope of the present disclosure.

[0067] Reference can be made to Figure 3 for describing the operation of the pixel PX of Figure 2 .

[0068] Figure 3 is a waveform chart showing an example of a signal measured in the pixel PX of Figure 2 .

[0069] Referring to Figure 2 and Figure 3 , the first period P1 (or a display period) can correspond to a period in which the pixel PX emits light and / or a period in which an effective data voltage is applied (or written) to the pixel PX to cause the pixel PX to emit light. The second period P2 (or a sensing period) can correspond to a period in which a characteristic of the light emitting element in the pixel PX is sensed, and the pixel PX can not emit light in the second period P2. The first period P1 and the second period P2 can be included in one frame section (e.g., a section in which one frame of an image is displayed). Although Figure 3 shows that the first period P1 is located before the second period P2, the present disclosure is not limited thereto. For example, the second period P2 can be located before the first period P1 within one frame section.

[0070] In the first period P1, the scan signal S[n] can have a gate-on voltage level ON, and the sensing control signal SEN[n] can have the gate-on voltage level ON. Here, the gate-on voltage level ON can correspond to a voltage level for turning on a transistor. The data voltage DATA in the kth data line DLk can have the nth data voltage level VDATA[n].

[0071] In the first period P1, the second transistor T2 of the pixel PX can be turned on in response to the scan signal S[n] having the gate-on voltage level ON, and a data voltage DATA of the nth data voltage level VDATA[n] can be applied to the first node N1. Also, the third transistor T3 of the pixel PX can be turned on in response to the sensing control signal SEN[n] having the gate-on voltage level ON, and an initialization voltage VINIT applied to the kth sensing line RLk can be provided to the second node N2 through the third transistor T3. Here, the initialization voltage VINIT can have a voltage level lower than an operation voltage level (e.g., a threshold voltage level) of the light emitting element LED. Accordingly, a voltage corresponding to a difference between the data voltage DATA at the first node N1 and the initialization voltage VINIT at the second node N2 (i.e., a data voltage in which a threshold voltage of the first transistor T1 is compensated for) can be stored in the storage capacitor Cst. An amount of drive current flowing through the first transistor T1 can be determined according to the voltage stored in the storage capacitor Cst. When the sensing control signal SEN[n] is switched from the gate-on voltage level ON to the gate-off voltage level OFF in the first period P1, the light emitting element LED can emit light with a luminance corresponding to the amount of drive current.

[0072] In the second period P2, the scan signal S[n] can partially have the gate-on voltage level ON, and the sensing control signal SEN[n] can partially have the gate-on voltage level ON and the gate-off voltage level OFF. In at least a part of the second period P2, the data voltage DATA in the kth data line DLk can have a reference voltage level VREF.

[0073] In the second period P2, the second transistor T2 of the pixel PX can be turned on in response to the scan signal S[n] having the gate-on voltage level ON, and a data voltage DATA of the reference voltage level VREF can be applied to the first node N1. The third transistor T3 of the pixel PX can be turned on in response to the sensing control signal SEN[n] having the gate-on voltage level ON. In a part of the second period P2 in which the sensing control signal SEN[n] has the gate-on voltage level ON, an initialization voltage VINIT is applied to the kth sensing line RLk, and the initialization voltage VINIT can be applied to the second node N2 through the third transistor T3.

[0074] When the sensing control signal SEN[n] is switched from the gate-on voltage level ON to the gate-off voltage level OFF, a voltage corresponding to the threshold voltage of the first transistor T1 and the operation voltage level (e.g., threshold voltage) of the light emitting element LED can be stored in the storage capacitor Cst. Subsequently, when the scan signal S[n] is switched from the gate-on voltage level ON to the gate-off voltage level OFF and the sensing control signal SEN[n] has the gate-on voltage level ON, a current corresponding to the operation voltage level of the light emitting element LED can flow to the k-th sensing line RLk through the third transistor T3.

[0075] Figure 4 is a graph illustrating a voltage-current characteristic of the first transistor T1 included in the pixel PX of the display device 100. Figure 2

[0076] Referring to Figure 2 and Figure 4 , a first characteristic curve CT1 represents a current-voltage characteristic of the first transistor T1. A second characteristic curve CT2 represents a current-voltage characteristic of the first transistor T1 when the threshold voltage Vth of the first transistor T1 is shifted in a positive direction. In this case, the threshold voltage Vth of the first transistor T1 according to the second characteristic curve CT2 can be represented as a maximum threshold voltage Vth[max]. A third characteristic curve CT3 represents a current-voltage characteristic of the first transistor T1 when the threshold voltage Vth of the first transistor T1 is shifted in a negative direction. The threshold voltage Vth of the first transistor T1 according to the third characteristic curve CT3 can be represented as a minimum threshold voltage Vth[min]. A difference between the maximum threshold voltage Vth[max] and the minimum threshold voltage Vth[min] can be represented as "ΔVth". During use of the pixel PX (or the display device 100 shown in Figure 1 the threshold voltage Vth of the first transistor T1 can change with a shift of ΔVth.

[0077] The display device 100 (referring to Figure 1 ) can adjust the data voltage DATA and the initialization voltage VINIT so that a luminance corresponding to black is 0 nit (a unit of measurement of luminance). For example, the display device 100 can measure the threshold voltage Vth of the first transistor T1 using an external compensation technique, and adjust the data voltage DATA so that a difference between the data voltage (e.g., a data voltage corresponding to a gray value of 0) DATA corresponding to black and the threshold voltage Vth of the first transistor T1 is equal to the initialization voltage VINIT.

[0078] Figure 5 is a block diagram illustrating an example of the timing controller 140 included in the display device 100 of Figure 1 Figure 6A to Figure 6D ​​is a graph showing a gray-voltage characteristic of a pixel PX compensated for by a timing controller 140. Figure 1 is a graph showing a gray-voltage characteristic of a pixel PX compensated for by a timing controller 140.

[0079] Referring to Figure 1 and Figure 5 , the timing controller 140 can include a first compensation circuit (also referred to herein as a gamma compensation circuit or a digital gamma compensation circuit) 510, a second compensation circuit (also referred to herein as an optical compensation circuit or a deterioration compensation circuit) 520, a third compensation circuit (also referred to herein as a reference gray compensation circuit) 530, and a fourth compensation circuit (also referred to herein as an external compensation circuit) 540.

[0080] The first compensation circuit 510 can convert an input gray value (also referred to herein as a first gray value) GRAY to a first gray voltage value GRAY_C1 according to a reference gamma curve of a first voltage range. Here, the input gray value GRAY can be included in the input image data DATA1 described with reference to Figure 1 For example, the first compensation circuit 510 can convert the input gray value GRAY to the first gray voltage value GRAY_C1 according to a 2.2 gamma curve. Here, the first gray voltage value GRAY_C1 can be a data value representing a data voltage.

[0081] Referring to Figure 6A , a first curve CURVE1 (or a first graph) indicates a relationship between the input gray value GRAY and a gate-source voltage Vgs of the first transistor T1 (with reference to Figure 2 ). Here, the gate-source voltage Vgs of the first transistor T1 can represent an operation value obtained by subtracting an initialization voltage VINIT (with reference to Figure 2 ) provided to a source electrode (for example, a second node N2 described with reference to Figure 3 ) of the first transistor T1 from a data voltage provided to a gate electrode of the first transistor T1 and a threshold voltage of the first transistor T1. In Figure 6A , the input gray value GRAY has a range from a gray value 0G of 0 to a gray value 1024G of 1024, but this is only an example, and the range of the input gray value GRAY is not limited thereto.

[0082] As the input gray value GRAY increases according to the first curve CURVE1, the gate-source voltage Vgs of the first transistor T1 can linearly increase. For example, a plurality of voltage values can be generated by linearly dividing a maximum voltage value and a minimum voltage value of the first voltage range VR1, and the input gray value GRAY can correspond to one of the plurality of voltage values.

[0083] The gate-source voltage Vgs of the first transistor T1 corresponding to the input grayscale value GRAY within the low grayscale range (e.g., a grayscale value 0G of 0 to a grayscale value 100G of 100) can be less than a reference voltage (e.g., 0V). In this case, referring to Figure 4 the first characteristic curve CT1 illustrated in FIG. 10, the current (i.e., the driving current of the first transistor T1) corresponding to the input grayscale value GRAY within the low grayscale range is 0, and the light emitting element LED can not emit light. The gate-source voltage Vgs of the first transistor T1 corresponding to the input grayscale value GRAY above the low grayscale range (e.g., a grayscale value 100G of 100 to a grayscale value 1024G of 1024) can be greater than the reference voltage. Figure 2

[0084] Referring to Figure 6B , the second curve CURVE2 represents a relationship between the input grayscale value GRAY and the first grayscale voltage value GRAY_C1 (or the gate-source voltage Vgs of the first transistor T1).

[0085] According to the second curve CURVE2, the first grayscale voltage value GRAY_C1 (or the gate-source voltage Vgs of the first transistor T1) corresponding to the input grayscale value GRAY within the low grayscale range (e.g., a grayscale value 0G of 0 to a grayscale value 100G of 100) can be converted to a reference voltage (e.g., 0V) or a value similar to the reference voltage. Accordingly, the input grayscale value GRAY in the first voltage range VR1 can be mapped to the first grayscale voltage value GRAY_C1 in the second voltage range VR2.

[0086] Referring back to Figure 5 , the second compensation circuit 520 can calculate the second grayscale voltage value (or the first voltage value) GRAY_C2 by adding a compensation value (or a voltage compensation value) to the first grayscale voltage value GRAY_C1. Here, the compensation value can be pre-set based on the characteristic deviation of the pixel PX in the display unit 110 described with reference to Figure 1 , or can be calculated based on the electrical and / or optical degradation of the pixel PX.

[0087] In an embodiment, the second compensation circuit 520 can calculate the compensation value of the first grayscale voltage value GRAY_C1 using at least one of an optical compensation technique, a degradation compensation technique, and a brightness reduction technique, and generate the second grayscale voltage value GRAY_C2 by compensating the first grayscale voltage value GRAY_C1 using the compensation value.

[0088] Here, the optical compensation technique (e.g., near distance uniformity or ASRU) can be measured by a brightness measurement device during a manufacturing and / or inspection process of the display apparatus 100 (with reference to Figure 1 ) or the display unit 110 (with reference to Figure 1 ​The display unit 110) based on the luminance deviation of the display apparatus 100, and stores a compensation value for the luminance deviation of each zone (or each pixel PX) of the display apparatus 100, and can compensate the voltage value using the compensation value stored in advance. In this case, the compensation value can include a gain and an offset for indicating a relationship between a gray value and a luminance of each zone of the display apparatus 100, and can be stored in the storage in the form of a look-up table.

[0089] The degradation compensation technique (e.g., image sticking compensation or ISC) can accumulate a driving time (and a gray value) of each pixel PX to generate stress data (stress profile or cumulative data), calculate a compensation value based on a predetermined life curve and predetermined stress data, and compensate the voltage value based on the calculated compensation value. Here, the predetermined life curve can indicate a degree of degradation of the pixel PX over time, and the compensation value can be stored in a separate look-up table together with the stress data.

[0090] The luminance reduction technique (e.g., logo fader or LF) can detect a specific zone (e.g., a zone corresponding to a logo) having a condition that accelerates degradation of the display unit 110, and reduce the voltage value corresponding to the detected zone at a predetermined ratio or a predetermined value. Conversely, the luminance reduction technique can divide the display unit 110 into a center zone and an outer zone surrounding the center zone, and can reduce the voltage value corresponding to the outer zone.

[0091] As described above, the second compensation circuit 520 can compensate the first gray voltage value GRAY_C1 using various digital compensation techniques such as the optical compensation technique, the degradation compensation technique, and the luminance reduction technique.

[0092] Referring to Figure 6C The third curve CURVE3 indicates a relationship between the input gray value GRAY and the second gray voltage value GRAY_C2 (or the gate-source voltage Vgs of the first transistor T1).

[0093] According to the third curve CURVE3, the input gray value GRAY in the low gray range can be corrected to be less than a reference voltage (e.g., 0V).

[0094] The compensation value (i.e., a compensation value calculated using at least one of the optical compensation technique, the degradation compensation technique, and the luminance reduction technique) can have a negative value or a positive value. Accordingly, the second gray voltage value GRAY_C2 in the low gray range can be less than a reference voltage. In this case, the input gray value GRAY can be corrected to be greater than the reference voltage from the reference Figure 6BThe first gray voltage value GRAY_C1 within the second voltage range VR2 is mapped to a second gray voltage value GRAY_C2 within a third voltage range VR3.

[0095] When the second gray voltage value GRAY_C2 according to the third curve CURVE3 is compensated by the external compensation technique, an input gray value GRAY in a low gray range (for example, a third gray voltage value GRAY_C3 corresponding to a gray value 0G to 100G from a gray value 0 to 100, or a gate-source voltage Vgs of the first transistor T1) can be less than the reference voltage. That is, a compensation operation (that is, a compensation operation of the fourth compensation circuit 540 or a compensation value) using the external compensation technique can be canceled by a compensation operation (or a compensation value) of the second compensation circuit 520, and a gate-source voltage Vgs having a negative value can be applied to the first transistor T1. In this case, the light emitting element LED can not emit light.

[0096] Referring back to Figure 5 , the third compensation circuit 530 can map the input gray value GRAY from the second gray voltage value GRAY_C2 within the third voltage range VR3 to a third gray voltage value GRAY_C3 within a fourth voltage range VR4 (refer to Figure 6D ).

[0097] In an embodiment, the third compensation circuit 530 can scale the second gray voltage value GRAY_C2 in the third voltage range VR3 based on a maximum voltage value and a minimum voltage value of the third voltage range VR3, and shift the scaled second gray voltage value into the fourth voltage range VR4. For example, the third compensation circuit 530 can map the minimum voltage value of the third voltage range VR3 to a voltage value corresponding to a sum (total voltage) of an initialization voltage VINIT (refer to Figure 3 ) and a threshold voltage of the first transistor T1 (refer to Figure 2 ).

[0098] In another embodiment, the third compensation circuit 530 can re-map the input gray value GRAY from the second gray voltage value GRAY_C2 to the third gray voltage value GRAY_C3 using a predetermined look-up table.

[0099] Referring to Figure 6D , a fourth curve CURVE4 represents a relationship between the input gray value GRAY and the third gray voltage value GRAY_C3 (or the gate-source voltage Vgs of the first transistor T1).

[0100] According to the fourth curve CURVE4, the third gray voltage value GRAY_C3 can be greater than the reference voltage throughout the range of the input gray level value GRAY.

[0101] Referring toFigure 5 、 Figure 6C and Figure 6D Although the implementation of remapping the second gray voltage value GRAY_C2 to the third gray voltage value GRAY_C3 over the entire range of the input gray value GRAY has been described as an example, the operation of the third compensation circuit 530 is not limited thereto. For example, the third compensation circuit 530 can remap the second gray voltage value GRAY_C2 to the third gray voltage value GRAY_C3 only in a partial range (e.g., a low gray range of a gray value 100G less than 100) of the input gray value GRAY. For example, the third compensation circuit 530 can map the input gray value GRAY of the partial range (e.g., the low gray range of the gray value 100G less than 100) to a specific voltage (e.g., a sum of the initialization voltage VINIT and the threshold voltage of the first transistor T1) similarly to the second curve CURVE2 shown in Figure 6B .

[0102] Referring back to Figure 5 , the fourth compensation circuit 540 can calculate the fourth gray voltage value GRAY_C4 by compensating the third gray voltage value GRAY_C3 based on the sensed voltage VSENSE (e.g., the threshold voltage of the first transistor T1).

[0103] As described with reference to Figure 5 , the fourth compensation circuit 540 can calculate the fourth gray voltage value GRAY_C4 by adding (or subtracting) the threshold voltage of the first transistor T1 (or a voltage value corresponding to the threshold voltage) measured by the sensing unit 150 (refer to Figure 1 ) to (or from) the third gray voltage value GRAY_C3.

[0104] The fourth gray voltage value GRAY_C4 can be provided to the data driver 130 (refer to Figure 1 ), and the data driver 130 can provide a data voltage corresponding to the fourth gray voltage value GRAY_C4 to the pixel PX (refer to Figure 1 ).

[0105] As described with reference to Figure 5 、 Figure 6A 、 Figure 6B 、 Figure 6C and Figure 6DThe timing controller 140 can first compensate for the first gray voltage value GRAY_C1 using a deterioration compensation technique to generate a second gray voltage value GRAY_C2 (i.e., the timing controller 140 can map the input gray value GRAY from the first gray voltage value GRAY_C1 to the second gray voltage value GRAY_C2). Thereafter, the timing controller 140 can convert the second gray voltage value GRAY_C2 to a third gray voltage value GRAY_C3 within the valid voltage range (i.e., the timing controller 140 can remap the input gray value GRAY to the third gray voltage value GRAY_C3). Thereafter, the timing controller 140 can compensate for the third gray voltage value GRAY_C3 using an external compensation technique to generate a fourth gray voltage value GRAY_C4. Accordingly, the data voltage corresponding to the gray value in the low gray range can be accurately compensated for by the external compensation technique, and the linearity of the emission characteristics of the pixel PX in the low gray range can be obtained.

[0106] Figure 7 FIG. 1 is a flowchart illustrating an example of performing gray voltage compensation according to an embodiment of the present disclosure.

[0107] Referring to Figure 1 , Figure 4 and Figure 7 , the display device 100 can perform gray voltage compensation. For example, Figure 1 the timing controller 140 of the display device 100 can perform gray voltage compensation.

[0108] The display device 100 can convert a first gray value (or an input gray value GRAY) of the pixel PX to a first gray voltage value according to a reference gamma curve (S710). As described with reference to Figure 5 , Figure 6A and Figure 6B , the display device 100 can convert the input gray value GRAY to the first gray voltage value GRAY_C1 within the second voltage range VR2.

[0109] The display device 100 can calculate a second gray voltage value (or a first voltage value) by adding the first gray voltage value and a compensation value (S720). Here, the compensation value can be pre-set based on a characteristic deviation of the pixel PX, or can be calculated based on a deterioration level of the pixel PX.

[0110] As described with reference to Figure 5 and Figure 6C , the display device 100 can obtain the compensation value using at least one of an optical compensation technique, a deterioration compensation technique, and a brightness reduction technique, and calculate the second gray voltage value GRAY_C2 based on the first gray voltage value GRAY_C1 and the compensation value.

[0111] The display apparatus 100 can calculate a third gray voltage value (or a second voltage value) by remapping the second gray voltage value from the third voltage range (or the first voltage range) to the fourth voltage range (or the second voltage range) (S730). As described with reference to Figure 5 and Figure 6D , the display apparatus 100 can remap the second gray voltage value GRAY_C2 within the third voltage range VR3 to the third gray voltage value GRAY_C3 within the fourth voltage range VR4 based on the minimum voltage value and the maximum voltage value of the third voltage range VR3.

[0112] A voltage difference between a data voltage corresponding to the third gray voltage value GRAY_C3 within the fourth voltage range VR4 and a threshold voltage of the first transistor T1 can be greater than or equal to the initialization voltage VINIT (refer to Figure 2 and Figure 3 ). In an embodiment, a gate-source voltage of the first transistor T1 can be greater than 0V over the entire range of the input gray value GRAY.

[0113] Subsequently, the display apparatus 100 can compensate the third gray voltage value GRAY_C3 (or the second voltage value) based on the threshold voltage of the first transistor T1 (S740). As described with reference to Figure 4 and Figure 5 , the display apparatus 100 can compensate the third gray voltage value GRAY_C3 based on a compensation value corresponding to the threshold voltage of the first transistor T1 sensed by the sensing unit 150.

[0114] The display apparatus 100 can supply a data voltage generated based on the compensated third gray voltage value GRAY_C3 (i.e., the fourth gray voltage value GRAY_C4 described with reference to Figure 5 or the compensated second voltage value) and the initialization voltage VINIT to the pixel PX through the data line and the sensing line, respectively (S750). As described with reference to Figure 2 and Figure 3 , the display apparatus 100 can supply a data signal to the data line and can supply the initialization voltage VINIT to the sensing line in synchronization.

[0115] According to embodiments of the present disclosure, the display apparatus and the driving method of the display apparatus can compensate a gray value (or a data signal) using a degradation compensation technique and remap the compensated gray value (or the compensated data signal) from a first voltage range to a second voltage range so that a voltage difference between a data voltage corresponding to a minimum gray value and a threshold voltage of a driving transistor is equal to an initialization voltage. Accordingly, compensation by an external compensation technique can be maintained and linearity of an emission characteristic of a pixel in a low gray range can be obtained.

[0116] The scope of the present disclosure is not limited to the exemplary embodiments described herein. In addition, it is to be construed that changes or modifications derived from the meaning and scope of the claims and their equivalent concepts are included in the scope of the present disclosure.

Claims

1. A display device, comprising: The display unit includes a data line, a sensing line, and a pixel connected to the data line and the sensing line. The pixel includes a light-emitting element and a first transistor for providing driving current to the light-emitting element. A timing controller that generates a first voltage value by compensating for a first grayscale value, and generates a second voltage value by remapping the first voltage value; A data driver that generates a data voltage based on the second voltage value during a display cycle and supplies the data voltage to the data line; as well as A sensing unit provides an initial voltage to the sensing line during the display cycle and senses the threshold voltage of the first transistor through the sensing line during the sensing cycle. The timing controller shifts the minimum voltage value within the first voltage range to the voltage value corresponding to the sum of the initialization voltage and the threshold voltage of the first transistor, and remaps the first voltage value within the first voltage range to the second voltage value within the second voltage range, so that the voltage difference between the data voltage and the threshold voltage of the first transistor is greater than or equal to the initialization voltage.

2. The display device as claimed in claim 1, wherein, The second voltage range is a subset of the first voltage range.

3. The display device as claimed in claim 2, wherein, The minimum voltage value of the second voltage range is greater than the minimum voltage value of the first voltage range, and Wherein, the maximum voltage value of the second voltage range is equal to the maximum voltage value of the first voltage range.

4. The display device as claimed in claim 3, wherein, According to the data voltage, a voltage greater than or equal to zero is applied between the gate electrode and the source electrode of the first transistor.

5. The display device as claimed in claim 1, wherein, For the first grayscale value, which is the minimum grayscale value corresponding to black, the voltage difference between the data voltage relative to the first grayscale value and the threshold voltage of the first transistor is equal to the initialization voltage.

6. The display device as claimed in claim 5, wherein, The pixels also include: A second transistor is connected between the data line and the first node; A storage capacitor, the storage capacitor being connected between the first node and the second node; and A third transistor is connected between the second node and the sensing line. Wherein, one electrode of the light-emitting element is connected to the second node, and The first transistor provides the drive current to the second node in response to the voltage of the first node.

7. The display device as claimed in claim 6, wherein, The first transistor comprises an oxide semiconductor.

8. The display device as claimed in claim 1, wherein, The timing controller includes: A first compensation circuit converts the first gray value into a first gray voltage value based on a reference gamma curve. The second compensation circuit calculates the first voltage value by adding the first gray-scale voltage value and the compensation value. A third compensation circuit calculates the second voltage value by remapping the first voltage value from the first voltage range to the second voltage range; and A fourth compensation circuit, which compensates for the second voltage value based on the threshold voltage of the first transistor to output the value. The compensation value is preset based on the characteristic deviation of the pixel, or calculated based on the degradation level of the pixel.

9. A display device, comprising: The display unit includes a data line, a sensing line, and a pixel connected to the data line and the sensing line. The pixel includes a light-emitting element and a transistor for providing driving current to the light-emitting element. A timing controller that generates a first voltage value by compensating for a first grayscale value, and generates a second voltage value by remapping the first voltage value; A data driver that generates a data voltage based on the second voltage value and supplies the data voltage to the data line; as well as The sensing unit provides an initial voltage to the sensing line. The timing controller shifts the minimum voltage value within the first voltage range to the voltage value corresponding to the sum of the initialization voltage and the threshold voltage of the transistor, and remaps the first voltage value within the first voltage range to the second voltage value within the second voltage range, so that the voltage difference between the data voltage and the threshold voltage of the transistor is greater than or equal to the initialization voltage.

10. A driving method for a display device, wherein, The display device includes a data line, a sensing line, and pixels connected to the data line and the sensing line, wherein each pixel includes a light-emitting element and a transistor for providing driving current to the light-emitting element, and the driving method includes: The first grayscale value of the pixel is converted into a first grayscale voltage value according to the reference gamma curve; The first voltage value is calculated by adding the first grayscale voltage value and the compensation value; The second voltage value is calculated by remapping the first voltage value from a first voltage range to a second voltage range; and An initialization voltage is provided to the pixel via the sensing line, and a data voltage generated based on the second voltage value is provided to the pixel via the data line. The compensation value is preset based on the characteristic deviation of the pixel, or calculated based on the degradation level of the pixel. The calculation of the second voltage value includes: By shifting the minimum voltage value within the first voltage range to the voltage value corresponding to the sum of the initialization voltage and the threshold voltage of the transistor, the first voltage value is remapped to the second voltage value, such that the voltage difference between the data voltage and the threshold voltage of the transistor is greater than or equal to the initialization voltage.

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