Display device

Abstract

The present invention relates to a display device. Specifically, a display device according to an embodiment of the present invention includes: a display unit including pixels; a sensing unit that measures a sensing current for each pixel and outputs a sensing current value; and a compensation unit that calculates a degradation weight value for each position of the pixel based on the sensing current value and a preset reference current value, accumulates the degradation degree reflecting the degradation weight value to update a degradation accumulation value, and generates an output gray value by reflecting the updated degradation accumulation value in an input gray value input from the outside.

Description

Technical Field

[0001] The present invention relates to a display device and a driving method thereof. Background Art

[0002] With the development of information technology, the importance of display devices as a connection medium between users and information is emerging. In response, the use of display devices such as liquid crystal display devices, organic light emitting display devices, and plasma display devices is increasing.

[0003] A display device may include a plurality of pixels, and the plurality of pixels can display various images by emitting light in various colors and brightnesses.

[0004] The plurality of pixels may include pixel circuits having substantially the same structure. However, as the display device becomes larger, process variations according to the position of the pixels may occur. Therefore, even transistors that perform the same function in each pixel may have different characteristics such as mobility and threshold voltage. Similarly, the threshold voltages of the light emitting diodes of each pixel may be different from each other.

[0005] Moreover, not only process variations occur, but also the degree of deterioration of the elements included in each pixel may be different for each pixel position according to the usage frequency and ambient temperature of each pixel during user use of the product.

[0006] In such a process, a technology for sensing characteristic information (such as mobility and threshold voltage) of the elements included in pixels and compensating the characteristic information changed due to deterioration is required. Also, a technology for more accurately compensating characteristic information by continuously reflecting the degree of deterioration that is different for each pixel position in the compensation logic is required. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a display device and a driving method thereof that can sense the characteristic information of pixels according to the position of each pixel and accurately compensate the characteristic information according to the position of each pixel.

[0008] The technical problems of the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned can be clearly understood by those skilled in the art through the following description.

[0009] To solve the above technical problems, on one side, a display device according to an embodiment of the present invention includes: a display unit including pixels; a sensing unit that measures a sensing current for each pixel and outputs a sensing current value; and a compensation unit that calculates a deterioration weight value for each position of the pixel based on the sensing current value and a preset reference current value, accumulates the deterioration degree reflecting the deterioration weight value, updates the deterioration accumulation value each time the sensing current is measured, and generates an output gray value by reflecting the updated deterioration accumulation value in the input gray value input from the outside.

[0010] Here, the pixels can be divided into a plurality of blocks, the number of blocks is less than or equal to the number of pixels, the sensing unit measures the sensing current generated by each of the plurality of pixels included in the block, and calculates a block current value for each block based on the measured sensing current.

[0011] Here, the compensation unit can calculate a block deterioration weight value corresponding to the block based on the block current value and the reference current value, reflect the block deterioration weight value on the block deterioration degree corresponding to the block, and accumulate the block deterioration degree, and then update the block deterioration accumulation value, and reflect the updated block deterioration accumulation value in the input gray value, and then generate a block output gray value for the block.

[0012] Here, the compensation unit can obtain a first block deterioration degree corresponding to the first block and a second block deterioration degree corresponding to at least one second block adjacent to the first block, calculate a difference value between the first block deterioration degree and the second block deterioration degree, and if the difference value is above a reference value, store information about the first block.

[0013] Here, the compensation unit can confirm whether the display device is turned off. If the display device is turned off, it calculates a block current value corresponding to the stored first block, calculates a block deterioration weight value based on the block current value corresponding to the first block and the reference current value, and accumulates the first block deterioration degree reflecting the block deterioration weight value to update the block deterioration accumulation value.

[0014] Here, the pixel may include: a first transistor including a gate electrode connected to a first node, a first electrode connected to a first power supply, and a second electrode connected to a second node; a second transistor including a gate electrode connected to a first scan line, a first electrode connected to a data line, and a second electrode connected to the first node; a third transistor including a gate electrode connected to a second scan line, a first electrode connected to the second node, and a second electrode connected to a sensing line; and a light emitting diode including an anode connected to the second node and a cathode connected to a second power supply.

[0015] Here, when measuring the sensing current, a voltage corresponding to reference gray data may be applied to the first node, and the reference gray data is data in which the characteristics of the first transistor are compensated.

[0016] Here, the characteristics of the first transistor may include at least one of the threshold voltage and the mobility of the first transistor.

[0017] Here, the voltage of the second power supply may be set to be greater than the voltage of the first power supply during measurement of the sense current.

[0018] Here, the deterioration accumulation value may increase as the degree of deterioration increases, the degree of deterioration increases as the deterioration weight value increases, and the deterioration weight value is determined based on the ratio of the sense current value to the reference current value.

[0019] Here, the display device may further include: a temperature sensor that measures the ambient temperature around the display unit, and a compensation unit that reflects the input gray value of the pixel and the ambient temperature in the degree of deterioration, and then accumulates the degree of deterioration.

[0020] On the other hand, a display device according to another embodiment of the present invention includes: a display unit including a plurality of pixels connected to a data line, a scan line, and a first power supply line; a current sensor that senses a sense current flowing in the first power supply line and provides a sense current value; and a compensation unit that calculates a deterioration weight value of the pixel by position based on the sense current value and a preset reference current value, accumulates the degree of deterioration reflecting the deterioration weight value and updates the deterioration accumulation value every time the sense current is measured, and reflects the updated deterioration accumulation value in the input gray value input from the outside to generate an output gray value.

[0021] Here, the pixels may be divided into a plurality of blocks, the number of blocks is less than or equal to the number of pixels, the current sensor measures the sense current occurring in each of the plurality of pixels included in the block, and calculates a block current for each block based on the sensed sense current.

[0022] Here, the compensation unit may calculate a block deterioration weight value corresponding to the block based on the block current value and the reference current value, reflect the block deterioration weight value in the block deterioration degree corresponding to the block, and accumulate the block deterioration degree to update the block deterioration accumulation value, and reflect the updated block deterioration accumulation value in the input gray value to generate a block output gray value for the block.

[0023] Here, the compensation unit may obtain a first block deterioration degree corresponding to the first block and a second block deterioration degree corresponding to at least one second block adjacent to the first block, calculate a difference value between the first block deterioration degree and the second block deterioration degree, and if the difference value is above a reference value, store information about the first block.

[0024] Here, the compensation unit can confirm whether the display device is turned off. If the display device is turned off, it calculates the block current corresponding to the stored first block, and calculates the block degradation weight value based on the block current corresponding to the first block and the reference current value. It accumulates the first block degradation degree reflecting the block degradation weight value, and then updates the block degradation accumulation value.

[0025] On another aspect, a driving method of a display device according to an embodiment of the present invention includes the following steps: measuring a sensing current for each pixel included in the display device and outputting a sensing current value; calculating a degradation weight value for each position of the pixel based on the sensing current value and a preset reference current value; accumulating the degradation degree reflecting the degradation weight value and updating the degradation accumulation value every time the sensing current is measured; and generating an output gray value by reflecting the updated degradation accumulation value in the input gray value input from the outside.

[0026] Here, the pixels can be divided into multiple blocks, and the number of blocks is less than or equal to the number of pixels. In the step of outputting the sensing current value, the sensing current generated by each of the multiple pixels included in the block is measured, and the block current is calculated for each block based on the sensed sensing current.

[0027] Here, in the step of calculating the degradation weight value, the block degradation weight value corresponding to the block can be calculated based on the block current value and the reference current value. In the step of updating the degradation accumulation value, the block degradation weight value is reflected in the block degradation degree corresponding to the block, and the block degradation degree is accumulated, and then the block degradation accumulation value is updated. In the step of generating the output gray value, the updated block degradation accumulation value is reflected in the input gray value, and then the block output gray value for the block is generated.

[0028] Here, the degradation accumulation value can increase as the degradation degree increases, the degradation degree increases as the degradation weight value increases, and the degradation weight value is determined based on the ratio of the sensing current value to the reference current value.

[0029] Specific matters of other embodiments are included in the detailed description and the drawings.

[0030] As described above, embodiments of the present invention can provide a display device and its driving method capable of sensing characteristic information of pixels according to the position of each pixel and accurately compensating the characteristic information according to the position of each pixel.

[0031] The effects according to the embodiments are not limited to the content illustrated above, and more various effects are included in this specification. Brief Description of the Drawings

[0032] Figure 1 It is a diagram for explaining a display device according to an embodiment of the present invention.

[0033] Figure 2It is a diagram for explaining a pixel unit according to an embodiment of the present invention.

[0034] Figure 3 And Figure 4 It is a diagram for explaining a display period of a pixel according to an embodiment of the present invention.

[0035] Figure 5 And Figure 6 It is a diagram for explaining a mobility sensing period of a driving transistor according to an embodiment of the present invention.

[0036] Figure 7 And Figure 8 It is a diagram for explaining a threshold voltage sensing period of a driving transistor according to an embodiment of the present invention.

[0037] Figures 9 to 11 It is a diagram for explaining a threshold voltage sensing period of a light emitting diode according to an embodiment of the present invention.

[0038] Figure 12 It is a diagram for explaining an embodiment in which a compensation unit calculates a deterioration degree and updates a block deterioration accumulation value according to an embodiment of the present invention.

[0039] Figure 13 It is a diagram for explaining an embodiment in which a block deterioration accumulation value is updated for a specific block according to an embodiment of the present invention.

[0040] Figure 14 It is a diagram for explaining a display device according to another embodiment of the present invention. Detailed Description of the Invention

[0041] If reference is made to the embodiments described in detail hereinafter with the attached Figure 1 The advantages, features, and methods of achieving this of the present invention will become clear. However, the present invention is not limited to the embodiments disclosed below, and it can be implemented in various different forms. Merely, the embodiments of the present invention are provided to make the disclosure of the present invention complete and to fully inform those with ordinary knowledge in the technical field to which the present invention pertains of the scope of the present invention. The present invention is only limited by the scope of the claims.

[0042] Although terms such as first and second are used to explain various components, these components are clearly not limited by these terms. The above terms are only used to distinguish one component from another. Therefore, it is obvious that within the technical idea of the present invention, the first component mentioned below can also be the second component. As long as there is no clear indication of a different meaning in the context, a singular expression includes a plural expression.

[0043] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The same or similar reference numerals are used for the same components in the drawings.

[0044] Figure 1 FIG. is a diagram for explaining a display device according to an embodiment of the present invention.

[0045] A display device 10 according to an embodiment of the present invention may include a timing control unit 11, a data driver unit 12, a scan driver unit 13, a display unit 14, a sensing unit 15, a compensation unit 16, and the like.

[0046] The timing control unit 11 may receive various gray scale values (or gray scale data) and control signals regarding each image frame from an external processor (not shown). The timing control unit 11 may render the gray scale values in a manner corresponding to the specification of the display device 10. For example, the external processor may provide red gray scale values, green gray scale values, and blue gray scale values for each unit dot. However, for example, when the display unit 14 has a pentile structure, since pixels are shared between adjacent unit dots, the pixels may not correspond one-to-one to each gray scale value. In this case, rendering of the gray scale values is required. In the case where the pixels correspond one-to-one to each gray scale value, rendering of the gray scale values may not be required. The rendered or unrendered gray scale values may be provided to the data driver unit 12. And, in order to display a frame, the timing control unit 11 may provide control signals suitable for each specification to the data driver unit 12, the scan driver unit 13, the sensing unit 15, and the like.

[0047] The data driver unit 12 may generate data voltages to be provided to data lines D1, D2, D3, Dm by using the gray scale values and the control signals. For example, the data driver unit 12 may sample the gray scale values by using a clock signal, and apply data voltages corresponding to the gray scale values to the data lines D1 to Dm in pixel row units. m may be an integer greater than 0.

[0048] The scan driver unit 13 receives a clock signal, a scan start signal, etc. from the timing control unit 11, and then generates a first scan signal to be provided to first scan lines S11, S12, S1n and a second scan signal to be provided to second scan lines S21, S22, S2n. n may be an integer greater than 0.

[0049] The scan driver unit 13 may sequentially supply a first scan signal having a pulse with a conductive level to the first scan lines S11, S12, S1n. And, the scan driver unit 13 may sequentially supply a second scan signal having a pulse with a conductive level to the second scan lines S21, S22, S2n.

[0050] Although not illustrated, the scan driver unit 13 may include a first scan driver unit connected to the first scan lines S11, S12, S1n and a second scan driver unit connected to the second scan lines S21, S22, S2n. Each of the first scan driver unit and the second scan driver unit may include scan stages configured in the form of a shift register. Each of the first scan driver unit and the second scan driver unit may generate a scan signal by sequentially transmitting a scan start signal in the form of a pulse as a conduction level to the next scan stage under the control of a clock signal.

[0051] According to an embodiment, the first scan signal and the second scan signal may be the same (refer to Figure 14 ). In this case, the first scan line and the second scan line connected to each pixel PXij may be connected to the same node. In this case, the scan driver unit 13 may also be configured as a single scan driver unit instead of being divided into a first scan driver unit and a second scan driver unit.

[0052] The sensing unit 15 may receive a control signal from the timing control unit 11 and supply an initialization voltage to the sensing lines I1, I2, I3, Ip, or receive sensing signals through the sensing lines I1, I2, I3, Ip. For example, the sensing unit 15 may supply an initialization voltage to the sensing lines I1, I2, I3, Ip during at least a part of the display period. For example, the sensing unit 15 may receive sensing signals through the sensing lines I1, I2, I3, Ip during at least a part of the sensing period. p may be an integer greater than 0.

[0053] The sensing unit 15 may include sensing channels connected to the sensing lines I1, I2, I3, Ip. For example, the sensing lines I1, I2, I3, Ip and the sensing channels may correspond to each other one-to-one. This will be described later with reference to Figures 4 to 8 this.

[0054] As in this embodiment, the data driver unit 12 and the sensing unit 15 may be separately configured. However, in other embodiments, the data driver unit 12 and the sensing unit 15 may also be configured as one body.

[0055] The display unit 14 may include pixels. Each pixel PXij may be connected to a corresponding data line, scan line, and sensing line. The pixel PXij may be divided into multiple blocks. For example, each block may include the same number of pixels, and the blocks may not overlap with each other. In other embodiments, the blocks may also include different numbers of pixels. In other embodiments, the blocks may also share at least a part of the pixels (i.e., overlap).

[0056] A block is used to define a control unit for multiple pixels. It is a virtual element rather than a physical component. A block can be defined by being written into the memory before the product leaves the factory, or can be actively redefined during the use of the product.

[0057] The sensing unit 15 can measure the sensing current for each pixel and output the sensing current value. Specifically, the sensing unit 15 can generate a sensing current value by sensing the sensing current of only a part of the pixels or all the pixels for each block according to the control signal supplied from the timing control unit 11. Such a sensing unit 15 can be embodied as a sensing channel as described later.

[0058] The compensation unit 16 can calculate the degradation weight value of the pixel according to the position based on the sensing current value and a preset reference current value, update the degradation accumulation value by accumulating and reflecting the degradation degree of the degradation weight value, and reflect the updated degradation accumulation value in the input gray value input from the outside, and then generate an output gray value.

[0059] The reference current value can represent the current value expected when inputting reference gray data from the outside at the reference temperature. It can be pre-stored in the memory (not shown) before leaving the factory, or can be actively redefined during the use of the product.

[0060] The degradation weight value can represent a parameter that reflects the characteristic deviation of multiple pixels according to their positions. The degradation weight value can be set to an initial value before leaving the factory and can be updated according to the measured sensing current during the use of the product. The degradation weight value can be set to multiple values corresponding to each pixel. In addition, when multiple pixels are divided into the above-mentioned blocks, the degradation weight value can be set corresponding to each block. At this time, the degradation weight value corresponding to a specific block can be named the block degradation weight value. This will be specifically described later by referring to Figure 12 and Figure 13 This will be specifically described.

[0061] The degradation degree can represent the degree to which a specific pixel degrades according to its size. The above-mentioned degradation weight value, the gray acceleration of the gray value output after being compensated when inputting a predetermined gray value, the temperature acceleration according to the internal temperature in the display device 10, etc. can be reflected in the degradation degree. The degradation degree can also be set to multiple values corresponding to each pixel as described above, and can be set to multiple values corresponding to each block including a predetermined number of pixels. At this time, the degradation degree corresponding to a specific block can be named the block degradation degree.

[0062] The deterioration accumulation value can represent the accumulated value of the deterioration degree and can represent the value required to compensate the input grayscale value. Specifically, the deterioration accumulation value in the current image frame can be updated by adding the deterioration degree to the deterioration accumulation value up to the previous image frame. The deterioration accumulation value can also be set in multiple ways corresponding to each pixel as described above, and can be set in multiple ways corresponding to each block. At this time, the deterioration accumulation value corresponding to a specific block can be named the block deterioration accumulation value.

[0063] The input grayscale value, as grayscale data input from an external processor, can represent the grayscale data regarding the image frame. And, the output grayscale value can represent the grayscale data that the input grayscale value is compensated by the compensation unit 16 and input to the data driving unit 12.

[0064] In one embodiment, when the compensation unit 16 receives the input grayscale value and the ambient temperature regarding a pixel, the compensation unit 16 can use the input grayscale value and the ambient temperature regarding the pixel to calculate the deterioration degree. And, the compensation unit 16 can update the deterioration accumulation value by adding the calculated deterioration degree to the existing deterioration accumulation value, and generate an output grayscale value by reflecting the updated deterioration accumulation value on the input grayscale value.

[0065] The temperature sensor 17 can measure the ambient temperature of the display device. Specifically, the temperature sensor 17 can measure the ambient temperature of the display unit 14 and output information regarding the measured ambient temperature to the compensation unit 16. In one embodiment, when the pixels are divided into blocks, the temperature sensor 17 can measure the ambient temperature regarding each block unit by unit of each block. The embodiment of the present invention has the advantage of being able to be realized even if only one temperature sensor 17 is equipped.

[0066] Figure 2 is a diagram for explaining a pixel unit according to an embodiment of the present invention.

[0067] Refer to Figure 2 , the pixels PX1, PX2, PX3 can be divided by the blocks BL1, BL2, BL3. The number of the blocks BL1, BL2, BL3 can be less than or equal to the number of the pixels PX1, PX2, PX3. For example, each of the blocks BL1, BL2, BL3 can be divided in such a way as to include one or more pixels PX1, PX2, PX3.

[0068] Here, when each of the blocks BL1, BL2, BL3 includes only one pixel PX1, PX2, PX3, that is, when the number of the blocks BL1, BL2, BL3 is equal to the number of the pixels PX1, PX2, PX3, accurate deterioration compensation can be achieved, but there is a disadvantage of an increase in data storage cost and calculation cost.

[0069] In addition, when each of the blocks BL1, BL2, and BL3 includes more than two pixels PX1, PX2, and PX3, that is, when the number of blocks BL1, BL2, and BL3 is less than the number of pixels PX1, PX2, and PX3, although the data storage cost and the calculation cost are reduced, there is a disadvantage that accurate deterioration compensation cannot be achieved. The manufacturer of the display device 10 can consider such a trade-off relationship to determine the sizes of the blocks BL1, BL2, and BL3.

[0070] Although Figure 2 the number of the blocks BL1, BL2, and BL3 is illustrated as three, this is only an example for explaining the embodiments of the present invention and is not limited thereto.

[0071] In addition, when the display unit 14 has a resolution of ultra-high definition (UHD: Ultra High Definition), the display unit 14 may include 3840×2160 pixels. For example, 3840 pixels may exist in one horizontal line. For example, 3840 pixels may be connected to each scanning line. For example, 2160 pixels may exist in one vertical line. For example, 2160 pixels may be connected to one data line. At this time, each block may include the same number of pixels. If the number of blocks is N (N is a natural number), one block may include 3840×2160 / N pixels.

[0072] Figure 3 and Figure 4 is a diagram for explaining the display period of a pixel according to an embodiment of the present invention.

[0073] Referring to Figure 3 , exemplary waveforms of signals applied to the scanning lines S1i, S2i, the data line Dj, and the sensing line Ik connected to the pixel PXij during the display period are illustrated. k may be an integer greater than 0.

[0074] First, referring to Figure 4 , an exemplary configuration of the pixel PXij and the sensing channel 151 will be described first.

[0075] The pixel PXij may include transistors T1, T2, T3, a storage capacitor Cst, and a light-emitting diode LD.

[0076] The transistors T1, T2, and T3 can be composed of N-type transistors. In other embodiments, the transistors T1, T2, and T3 can also be composed of P-type transistors. In other embodiments, the transistors T1, T2, and T3 can be composed of a combination of N-type transistors and P-type transistors. A P-type transistor generally refers to a transistor in which the amount of current flowing through it increases when the voltage difference between the gate electrode and the source electrode increases negatively. An N-type transistor generally refers to a transistor in which the amount of current flowing through it increases when the voltage difference between the gate electrode and the source electrode increases positively. The transistors can be configured in various forms such as thin film transistors (TFTs), field effect transistors (FETs), bipolar junction transistors (BJTs), etc.

[0077] For the first transistor T1, the gate electrode can be connected to the first node N1, and the first electrode is connected to the first power supply ELVDD, and the second electrode is connected to the second node N2. The first transistor T1 can be named a driving transistor.

[0078] For the second transistor T2, the gate electrode can be connected to the first scan line S1i, and the first electrode is connected to the data line Dj, and the second electrode is connected to the first node N1. The second transistor T2 can be named a scan transistor.

[0079] For the third transistor T3, the gate electrode can be connected to the second scan line S2i, and the first electrode is connected to the second node N2, and the second electrode is connected to the sense line Ik. The third transistor T3 can be named a sense transistor.

[0080] For the storage capacitor Cst, the first electrode can be connected to the first node N1, and the second electrode is connected to the second node N2.

[0081] The light-emitting diode LD is an element that emits light with a predetermined brightness. For the light-emitting diode LD, the anode can be connected to the second node N2, and the cathode is connected to the second power supply ELVSS.

[0082] Generally, the voltage of the first power supply ELVDD can be greater than the voltage of the second power supply ELVSS. However, in special situations such as preventing the light-emitting diode LD from emitting light, the voltage of the second power supply ELVSS can also be set to be greater than the voltage of the first power supply ELVDD.

[0083] The sensing channel 151 can include switches SW1 to SW7, a sensing capacitor CS1, an amplifier AMP, and a sampling capacitor CS2.

[0084] One end of the second switch SW2 can be connected to the third node N3, and the other end is connected to the initialization power supply VINT.

[0085] The first input terminal (e.g., non-inverting terminal) of the amplifier AMP can be connected to the reference power supply VREF. The amplifier AMP can also be configured as an operational amplifier.

[0086] One end of the third switch SW3 can be connected to the third node N3, and the other end is connected to the second input terminal (e.g., inverting terminal) of the amplifier AMP.

[0087] The first electrode of the sensing capacitor CS1 can be connected to the second input terminal of the amplifier AMP, and the second electrode is connected to the output terminal of the amplifier AMP.

[0088] The sampling capacitor CS2 can be connected to the sensing capacitor CS1 through at least one of the switches SW5, SW6.

[0089] One end of the fourth switch SW4 can be connected to the first electrode of the sensing capacitor CS1, and the other end is connected to the second electrode of the sensing capacitor CS1.

[0090] One end of the fifth switch SW5 can be connected to the output terminal of the amplifier AMP, and the other end is connected to the fourth node N4.

[0091] One end of the sixth switch SW6 can be connected to the fourth node N4, and the other end is connected to the first electrode of the sampling capacitor CS2.

[0092] One end of the seventh switch SW7 can be connected to the first electrode of the sampling capacitor CS2, and the other end is connected to the analog-to-digital converter ADC.

[0093] One end of the first switch SW1 can be connected to the third node N3, and the other end is connected to the fourth node N4.

[0094] The sensing unit 15 can include a sensing channel 151 and an analog-to-digital converter ADC. For example, the sensing unit 15 can include an analog-to-digital converter corresponding to the number of sensing channels. In other examples, the sensing unit 15 can include a single analog-to-digital converter and perform time division and conversion on the sampled signals stored in the sensing channels.

[0095] Refer again to Figure 3 , during the display period, the sensing line Ik is connected to the initialization power supply VINT. During the display period, the second switch SW2 can be in the on state.

[0096] During the display period, the first switch SW1 and the third switch SW3 can be in an off state. Therefore, the sensing line Ik can be prevented from being connected to another power supply VREF.

[0097] During the display period, data voltages DS(i - 1)j, DSij, and DS(i + 1)j can be sequentially applied to the data line Dj in units of horizontal periods. For the first scan line S1i, a scan signal of a conductive level (high level) can be applied thereto in the corresponding horizontal period. And, a scan signal of a conductive level can be applied to the second scan line S2i in synchronization with the first scan line S1i. In other embodiments, during the display period, the state can also be such that a scan signal of a conductive level is always applied to the second scan line S2i.

[0098] For example, if a scan signal of a conductive level is applied to the first scan line S1i and the second scan line S2i, the second transistor T2 and the third transistor T3 can become conductive states. Therefore, a voltage corresponding to the difference between the data voltage DSij and the initialization power supply VINT is written into the storage capacitor Cst of the pixel PXij.

[0099] In the pixel PXij, according to the voltage difference between the gate electrode and the source electrode of the first transistor T1, the drive current amount flowing in the drive path connecting the first power supply ELVDD, the first transistor T1, and the second power supply ELVSS is determined. The light emission brightness of the light emitting diode LD can be determined according to the drive current amount.

[0100] After that, if a scan signal of a cut-off level (low level) is applied to the first scan line S1i and the second scan line S2i, the second transistor T2 and the third transistor T3 can become cut-off states. Therefore, regardless of the voltage change of the data line Dj, the voltage difference between the gate electrode and the source electrode of the first transistor T1 can be maintained by the storage capacitor Cst, and the light emission brightness of the light emitting diode LD can be maintained.

[0101] Figure 5 and Figure 6 is a diagram for explaining a mobility sensing period of a driving transistor according to an embodiment of the present invention.

[0102] Referring to Figure 5 , exemplary waveforms of signals applied to the scan lines S1i, S2i, the data line Dj, and the sensing line Ik connected to the pixel PXij during the mobility sensing period are illustrated. Figure 6 Illustrated is Figure 5 the state of the pixel PXij and the sensing channel 151 at the time point tm.

[0103] The sense voltages SS(i-1)j, SSij, and SS(i+1)j can be sequentially applied to the data line Dj. According to an embodiment, when sensing is performed only for one pixel row (pixels connected to the same scan line) during the mobility sensing period, the sense voltage SSij can also be applied only to the data line Dj, and the other sense voltages SS(i-1)j and SS(i+1)j are not applied to the data line Dj.

[0104] The sense line Ik can be connected to the reference power supply VREF. Referring to Figure 6 , the third switch SW3 can be in an on state. Since the non-inverting terminal and the inverting terminal of the amplifier AMP are in a virtual short state, it can be stated that the sense line Ik is connected to the reference power supply VREF.

[0105] If scan signals of a conductive level are applied to the first scan line S1i and the second scan line S2i in synchronization with the sense voltage SSij, the second transistor T2 and the third transistor T3 can be turned on.

[0106] Therefore, the sense voltage SSij can be applied to the first node N1 of the pixel PXij, and the voltage of the reference power supply VREF can be applied to the second node N2. The voltage difference between the sense voltage SSij and the voltage of the reference power supply VREF can be greater than the threshold voltage of the first transistor T1. Therefore, the first transistor T1 is turned on, and a sense current flows through the sense current path connecting the first power supply ELVDD, the first transistor T1, the second node N2, the third transistor T3, the third node N3, the third switch SW3, and the first electrode of the sense capacitor CS1. The sense current can include the characteristic information of the first transistor T1 (refer to [Equation 1]).

[0107] [Equation 1]

[0108]

[0109] At this time, Id can be the sense current flowing through the first transistor T1, u is the mobility, Co is the capacitance formed by the channel, the insulating layer, and the gate electrode of the first transistor T1, W is the width of the channel of the first transistor T1, L is the length of the channel of the first transistor T1, Vgs is the voltage difference between the gate electrode and the source electrode of the first transistor T1, and Vth is the threshold voltage value of the first transistor T1.

[0110] Here, Co, W, and L are fixed constants. Vth can be obtained by other detection methods (for example, referring to Figure 7 and Figure 8) It is detected. Vgs is the difference between the sensed voltage SSij and the voltage of the reference power supply VREF. Since the voltage of the third node N3 is fixed, the larger the sensed current Id, the lower the voltage of the fourth node N4. The voltage of the fourth node N4 can be stored as a sampling signal in the sampling capacitor CS2. Subsequently, the analog-to-digital converter ADC can convert the sampling signal stored in the sampling capacitor CS2 into a digital signal by turning on the seventh switch SW7, thereby calculating the magnitude of the sensed current Id. Therefore, the mobility u as the remaining variable can be obtained.

[0111] Figure 7 and Figure 8 is a diagram for explaining the threshold voltage sensing period of a driving transistor according to an embodiment of the present invention.

[0112] Referring to Figure 8 , the states of the pixel PXij and the sensing channel 151 at the time point th4 in Figure 7 are illustrated. The third switch SW3 and the fifth switch SW5 can remain in the off state, and the first switch SW1 remains in the on state.

[0113] Referring to Figure 7 , at the time point th1, the voltage of the second power supply ELVSS rises, thereby preventing the light-emitting diode LD from emitting light in advance.

[0114] Next, at the time point th2, the second switch SW2 is turned on, so that the sensing line Ik can be initialized to the voltage of the initialization power supply VINT.

[0115] Next, at the time point th3, a scanning signal with a conductive level can be applied to the first scanning line S1i and the second scanning line S2i. At this time, a sensing voltage SSth can be applied to the data line Dj. Therefore, the sensing voltage SSth can be maintained at the first node N1. And the sensing line Ik can be connected to the second node N2.

[0116] The voltage of the second node N2 can rise from the voltage of the initialization power supply VINT to the voltage SSth - Vth. If the voltage of the second node N2 rises to the voltage SSth - Vth, the first transistor T1 is turned off, so that the voltage of the second node N2 no longer rises.

[0117] The sixth switch SW6 can be in the on state. Therefore, the sampling signal can be stored in the sampling capacitor CS2. At this time, since the fourth node N4 is connected to the second node N2, the sampling signal includes the threshold voltage value Vth of the first transistor T1. By turning on the seventh switch SW7, the analog-to-digital converter ADC can convert the sampling signal into a digital signal.

[0118] Figures 9 to 11FIG. is a diagram for explaining a threshold voltage sensing period of a light-emitting diode according to an embodiment of the present invention. Referring to Figure 11 , the states of the pixel PXij and the sensing channel 151 at the time point td4 in Figure 9 are illustrated.

[0119] At the time point td1, a sensing voltage SSld may be applied to the data line Dj. A voltage of a reference power supply VREF may be applied to the sensing line Ik through the third switch SW3. At this time, scan signals of an on level may be applied to the scan lines S1i and S2i, and the second transistor T2 and the third transistor T3 may be turned on. Accordingly, the storage capacitor Cst may store a voltage difference between the sensing voltage SSld and the reference power supply VREF. For example, when measuring a sensing current, a voltage corresponding to reference gray data (e.g., the sensing voltage SSld) may be applied to the first node N1. At this time, the reference gray data may be data in which characteristics of the first transistor T1 are compensated, and here, the characteristics of the first transistor T1 may include at least one of a threshold voltage and a mobility of the first transistor T1.

[0120] At the time point td2, scan signals of an off level may be applied to the first scan line S1i and the second scan line S2i. Since the first transistor T1 remains in an on state through the storage capacitor Cst, the voltage of the second node N2 may increase corresponding to the degree of deterioration of the light-emitting diode LD. For example, the more severe the degree of deterioration of the light-emitting diode LD is, the greater the voltage of the second node N2 may increase. The voltage converging at the second node N2 may correspond to the threshold voltage of the light-emitting diode LD.

[0121] At the time point td3, scan signals of an on level may be applied to the first scan line S1i and the second scan line S2i. At this time, a data reference voltage Dref may be applied to the data line Dj. The data reference voltage Dref may be a voltage of an off level. Accordingly, the voltage of the second node N2 may be stably sensed by the sensing channel 151 while the first transistor T1 remains in an off state. During the sensing channel 151 senses the voltage of the second node N2, the fourth switch SW4 may be in an off state.

[0122] Since the third switch SW3 is in the on state and the voltage of the third node N3 is fixed to the voltage of the reference power supply VREF, the larger the voltage of the second node N2 (the more the supplied charge amount), the smaller the voltage of the fourth node N4 can be. The voltage of the fourth node N4 can be stored in the sampling capacitor CS2, and the analog-to-digital converter ADC can convert it into a digital value. Accordingly, the characteristic information corresponding to the threshold voltage of the light-emitting diode LD can be sensed in the form of a sensed current. At this time, the voltage of the second power supply ELVSS can be set to be greater than the voltage of the first power supply ELVDD during the measurement of the sensed current to prevent the sensed current from flowing into the light-emitting diode LD.

[0123] In addition, Figure 10 shows a method different from that shown in Figure 9 , that is, a method of sensing the characteristic information corresponding to the threshold voltage of the light-emitting diode in the form of a sensed current. That is, as Figure 10 shown, when a sensed voltage SSld of a conduction level is applied to the first node N1 through the data line Dj, the sensed current generated when the first transistor T1 conducts can be measured.

[0124] Referring to Figure 10 , at the time point te1, a scan signal of a conduction level can be applied to the first scan line S1i and the second scan line S2i, and a sensed voltage SSld of a conduction level can be applied to the data line Dj. At this time, the scan signal applied to the first scan line S1i and the sensed voltage SSld applied to the data line Dj can be continuously applied until the time point te2, and the scan signal applied to the second scan line S2i is applied in a pulse form before the time point te2. Therefore, at the time point te1, the voltage applied to the anode of the light-emitting diode LD through the scan signal applied to the second scan line S2i can be initialized, and a predetermined voltage can be generated at the second node N2 through the scan signal applied to the first scan line S1i and the sensed voltage SSld applied to the data line Dj.

[0125] At the time point te2, a scan signal of a cut-off level can be applied to the first scan line S1i, a scan signal of a conduction level can be applied to the second scan line S2i, and a sensed voltage SSld of a cut-off level can be applied to the data line Dj. At this time, while the first transistor T1 remains in the cut-off state, the voltage of the second node N2 can be stably sensed by the sensing channel 151.

[0126] From the time point te3 to the time point te4, a scan signal of a conduction level is applied to the first scan line S1i. Therefore, a sensed voltage SSld of a cut-off level can be applied to the gate electrode of the first transistor T1, so that the voltage applied to the second node N2 is reset.

[0127] Hereinafter, referring to Figure 12 the flowchart shown below, a method for updating the block deterioration accumulation value will be specifically described.

[0128] Figure 12 FIG. is a diagram for explaining an embodiment in which a compensation unit calculates a deterioration degree and updates a block deterioration accumulation value according to an embodiment of the present invention.

[0129] Referring to Figure 12 , a display device 10 according to an embodiment of the present invention inputs reference gray-scale data received from an external processor (S110). For example, the compensation unit 16 outputs the reference gray-scale data to the timing controller 11 so that the data driver unit 12 outputs a gray-scale value corresponding to the received reference gray-scale data (or, reference gray-scale value).

[0130] Next, the display device 10 measures the sensing current generated by each of the pixels included in the block (S120), and calculates the block current based on the measured sensing current (S130). Referring to Figure 2 , for example, the sensing unit 15 can measure the sensing current generated by each of the multiple pixels (for example, PX1, PX2, PX3) included in the block (for example, the first block BL1, the second block BL2, the third block BL3, etc.), and calculate the block current for each block BL1, BL2, BL3 based on the measured sensing current. Here, as an example, the block current can be the sum of the sensing currents generated by each of the multiple pixels (for example, PX1) included in a specific block (for example, the first block BL1), and as another example, it can be the average value obtained by dividing the sensing currents generated by each of the multiple pixels (for example, PX1) included in a specific block (for example, the first block BL1) by the number of multiple pixels (for example, PX1). However, it is not limited thereto.

[0131] Next, the display device 10 acquires a pre-stored reference current (S140). For example, the compensation unit 16 can acquire the reference current value stored in a memory (not shown).

[0132] Next, the display device 10 calculates a block deterioration weight value corresponding to each block based on the block current and the reference current (S150).

[0133] The above-mentioned deterioration weight value (or, block deterioration weight value) can be determined based on the ratio of the sensing current to the reference current. Specifically, the deterioration weight value (or, block deterioration weight value WP) can be determined by [Equation 2] described below.

[0134] [Equation 2]

[0135]

[0136] Here, I r is the reference current, I s is the sense current, and α represents the current acceleration coefficient. Here, the current acceleration coefficient can be pre-stored in a memory (not shown) before shipment, or can be actively redefined during product use.

[0137] Next, the display device 10 calculates the block degradation degree corresponding to each block based on the block degradation weight value (e.g., WP) (S160), and updates the block degradation cumulative value by adding the calculated block degradation degree to the current block degradation cumulative value (S170).

[0138] For example, with the first block BL1 as a reference, the compensation unit 16 can multiply the representative value of the first block of the input gray value (not shown) by the first block temperature and the first degradation weight value corresponding to the first block BL1 to generate the block degradation degree corresponding to the first block BL1. Then, the compensation unit 16 adds the block degradation degree corresponding to the first block BL1 to the block degradation cumulative value in the (n - 1)th image frame (not shown), thereby updating the block degradation cumulative value corresponding to the first block BL1 in the (n - 1)th image frame (refer to [Equation 3]).

[0139] [Equation 3]

[0140] ACD1[n] = ACD1[n - 1] + WP1 × BRV1[n] × TP1

[0141] Here, ACD1[n - 1] can be the block degradation cumulative value of the first block BL1 up to the (n - 1)th image frame, BRV1[n] is the first gray scale acceleration value (or the representative value of the first block of the input gray value (not shown)) of the first block BL1 in the nth image frame, TP1 is the first block temperature (TP1), WP1 is the degradation weight value of the first block BL1, and ACD1[n] is the block degradation cumulative value of the first block BL1 up to the nth image frame. The embodiment of updating the block degradation cumulative value using the above [Equation 3] etc. has been described with the first block BL1 as a reference, however, it is not limited thereto, and other blocks (e.g., BL2, BL3) included in the display unit 14 can all be applied.

[0142] In addition, the block representative value can be a value obtained by applying a weight value to the input gray value of the corresponding block and dividing by the number of input gray values. For example, when the weight values of the input gray values are all 1, the representative value can also represent an average value. In another example, the block representative value can also be the value obtained by summing the input gray values of the corresponding block. In yet another example, the block representative value can also correspond to the most significant bits (MSB: Most Significant Bits) of the value obtained by summing the input gray values of the corresponding block.

[0143] In Mathematical Formula 3, WP1 × BRV1[n] × TP1 may be the block degradation degree. That is, the larger the first block representative value (BRV1[n]) in the nth image frame and the larger the first block temperature (TP1), the larger the block degradation degree in the nth image frame may be. The block degradation degree may correspond to the degradation degree of the light-emitting diodes LD included in the pixels included in the corresponding block. If the light-emitting diode LD degrades, a larger drive current is required to emit light at the same level of brightness.

[0144] In addition, as the degradation degree (or the block degradation degree, such as WP × BRV[n] × TP) increases, the degradation accumulation value (or the block degradation accumulation value, such as ACD[n]) may increase. Here, as the degradation weight value (or the block degradation weight value, such as WP) increases, the degradation degree (or the block degradation degree, such as WP × BRV[n] × TP) may increase.

[0145] Although not shown, the display device 10 may reflect the updated block degradation accumulation value in the input gray value, and then generate an output gray value. For example, the compensation unit 16 may reflect the updated block degradation accumulation value in the input gray value, and then generate a block output gray value for the block.

[0146] In addition, although as described above, the compensation unit 16 may accumulate the block degradation accumulation value for each block, so as to perform compensation for each block, in the case where the output gray value of a specific block has a significant difference compared with the output gray values of the adjacent blocks, it is necessary to perform compensation only for the specific block. Hereinafter, a method for updating the block degradation accumulation value for a specific block will be specifically described with reference to the flowchart.

[0147] Figure 13 is a diagram for explaining an embodiment of updating the block degradation accumulation value for a specific block according to an embodiment of the present invention.

[0148] Refer to Figure 13 to confirm whether the display device 10 according to an embodiment of the present invention is turned on (S210). Specifically, the compensation unit 16 may confirm whether the display device 10 is turned on (Turn-On).

[0149] When the display device 10 is turned on (S210, Yes), the display device 10 obtains the block degradation degree corresponding to each block (S220). Here, the block degradation degree may be determined by the current generated for each block in a manner capable of displaying the input gray value and WP × BRV[n] × TP in the above [Mathematical Formula 3].

[0150] In Figure 2Based on the first block BL1 and the second block BL2 shown, for example, the compensation unit 16 can obtain the degree of deterioration of the first block corresponding to the first block BL1 (WP1 × BRV1[n] × TP1) and the degree of deterioration of the second block corresponding to the second block BL2 adjacent to the first block BL1 (WP2 × BRV2[n] × TP2). Here, Figure 2 The second block BL2 shown is adjacent to one side of the first block BL1, however, it is not limited thereto. Therefore, blocks adjacent to the other side, such as the third block BL3, can also be applied to the above example in the same way. And here, "first" and "second" are not limited to Figure 2 the situation shown.

[0151] In addition, the display device 10 calculates the difference value (ΔA) of the degree of deterioration between a specific block and an adjacent block (S230), and compares the difference value (ΔA) with a preset reference value (th) (S240). If the difference value (ΔA) is greater than or equal to the preset reference value (S240, yes), the information about the specific block is stored (S250). Refer to Figure 2 , for example, the compensation unit 16 can calculate the difference value (ΔA) between the degree of deterioration of the first block corresponding to the first block BL1 (WP1 × BRV1[n] × TP1) and the degree of deterioration of the second block corresponding to the second block BL2 (WP2 × BRV2[n] × TP2) based on the first block BL1. And if the difference value (ΔA) is greater than or equal to the reference value, the information about the first block BL1 can be stored.

[0152] Next, it is confirmed whether the display device 10 is turned off (S260). If it is still in the on state (S240, no), step S220 is executed again.

[0153] If the display device 10 is turned off (S240, yes), the display device 10 inputs the reference grayscale data received from an external processor (S270), then calculates the block current of the specific block and obtains the reference current (S280), then calculates the block deterioration weight value of the specific block and updates the degree of deterioration of the specific block (S290), and updates the block deterioration accumulation value of the specific block (S300). For example, in the case where the stored specific block is the first block BL1, the compensation unit 16 can confirm whether the display device 10 is turned off (Turn-Off). If the display device 10 is turned off, it calculates the block current corresponding to the stored first block BL1, and calculates the block deterioration weight value (WP1) based on the block current value corresponding to the first block BL1 and the reference current value pre-stored in the memory, and then accumulates the degree of deterioration of the first block reflecting the block deterioration weight value (WP1) to update the block deterioration accumulation value.

[0154] In addition, although not shown, as another embodiment, the compensation unit 16 may compare the difference value between the block degradation cumulative values (e.g., ACD[N]) of each block with the above-mentioned reference value, and then store information about a specific block having a difference value greater than or equal to the reference value. For example, the compensation unit 16 may calculate the difference value between the first block degradation cumulative value (e.g., ACD1[N]) of the first block BL1 and the second block degradation cumulative value (e.g., ACD2[N]) of the second block BL2, and if the difference value is greater than or equal to the reference value, store information about the first block BL1.

[0155] Figure 14 FIG. is a diagram for explaining a display device according to another embodiment of the present invention.

[0156] Refer to Figure 14 , a display device 10 according to another embodiment of the present invention may include a timing control unit 11, a data driving unit 12, a scan driving unit 13, a display unit 14, a current sensor 15_1, a compensation unit 16, a temperature sensor 17, and the like.

[0157] Since the timing control unit 11, the data driving unit 12, and the temperature sensor 17 are the same as those referred to in Figure 1 the above, their descriptions are omitted.

[0158] Figure 14 The scan driving unit 13 shown in Figure 1 combines the first scan lines S11, S12, S1n and the second scan lines S21, S22, S2n shown in Figure 1 into a single scan line S1, S2, S3, Si, S(i + 1), Sm, which is different from the scan driving unit 13 in

[0159] The display unit 14 includes pixels PXij, PXi(j + 1), and PX(i + 1)j. Each of the pixels PXij, PXi(j + 1), and PX(i + 1)j can be connected to corresponding data lines and scan lines. The scan transistor of pixel PXij can be connected to the i-th scan line Si and the j-th data line Dj. The scan transistor of pixel PXi(j + 1) can be connected to the i-th scan line Si and the (j + 1)-th data line D(j + 1). The scan transistor of pixel PX(i + 1)j can be connected to the (i + 1)-th scan line S(i + 1) and the j-th data line Dj. The pixels PXij, PXi(j + 1), and PX(i + 1)j can be commonly connected to the first power supply line ELVDDL. At this time, the pixels PXij, PXi(j + 1), and PX(i + 1)j can be commonly connected to the second power supply line ELVSSL. In other embodiments, the pixels PXij, PXi(j + 1), and PX(i + 1)j can also be connected to different second power supply lines. That is, the pixels PXij, PXi(j + 1), and PX(i + 1)j can also be applied with different second power supply voltages.

[0160] According to other embodiments, the pixels PXij, PXi(j + 1), and PX(i + 1)j can be commonly connected to the second power supply line ELVSSL, and the pixels PXij, PXi(j + 1), and PX(i + 1)j can also be connected to different first power supply lines. At this time, different from Figure 1 the embodiment of, the current sensor 15_1 can also be connected to the second power supply line ELVSSL to sense the current flowing through the second power supply line ELVSSL.

[0161] The display unit 14 can be divided into multiple blocks BL1, BL2. That is, multiple pixels PXij, PXi(j + 1), and PX(i + 1)j can be divided into multiple blocks BL1, BL2. Each of the blocks BL1, BL2 can include at least one pixel. For example, the first block BL1 can include pixels PXij, PX(i + 1)j, and the second block BL2 includes pixel PXi(j + 1). However, it is not limited thereto.

[0162] The current sensor 15_1 can be connected to the first power supply line ELVDDL. At this time, the current sensor 15_1 can sense the sensed current flowing in the first power supply line ELVDDL and provide a sensed current value. As described above, in other embodiments, the current sensor 15_1 can also be connected to the common second power supply line ELVSSL of the pixels PXij, PXi(j + 1), and PX(i + 1)j. At this time, the current sensor 15_1 can sense the current flowing in the second power supply line ELVSSL and provide a sensed current value. Since the current sensor 15_1 is connected to the common power supply line of all the pixels of the display unit 14, even if only one current sensor 15_1 is provided, the embodiments of the present invention can be implemented.

[0163] In one embodiment, as described above, the current sensor 15_1 can measure the sensed current generated by each of the multiple pixels PXij, PXi(j + 1), and PX(i + 1)j included in a block (e.g., BL1, BL2), and calculate the block current for each of the blocks BL1, BL2 based on the sensed sensed current.

[0164] The display device 10 can cause the blocks BL1, BL2 to emit light in sequence, and the current sensor 15_1 provides the sensed current value at each time point. At this time, the sensed current values can be stored in sequence, or the block current values corresponding to each of the blocks BL1, BL2 can be stored in sequence. For example, the pixels PXij, PX(i + 1)j of the first block BL1 can emit light in the first period and do not emit light in the second period after the first period. The pixel PXi(j + 1) of the second block BL2 can not emit light in the first period and emit light in the second period. The current sensor 15_1 can sense the current flowing in the first power supply line ELVDDL in the first period and provide a first sensed current value, and sense the current flowing in the first power supply line ELVDDL in the second period and provide a second sensed current value. A memory (not shown) can store the first sensed current value (or, the first block current value), and store the second sensed current value (or, the second block current value).

[0165] The process of storing the block current value can be executed once when the display device 10 is powered on. In other embodiments, the time point for executing this process can be set variably, or it can be executed multiple times.

[0166] Figure 14 The shown compensation unit 16 can be connected to the current sensor 15_1 and the timing control unit 11. Figure 14 The shown compensation unit 16 can calculate the degree of deterioration of each of the blocks BL1, BL2 based on the sensed current value provided by the current sensor 15_1 and the reference current value stored in a memory (not shown). In this regard Figure 14The compensation unit 16 shown in Figure 1 is different from the compensation unit 16 shown in Figure 14 and the other parts are all the same except for this. That is, Figure 14 the compensation unit 16 shown in Figure 14 can calculate the block deterioration weight value, update the block deterioration accumulation value, and output the block output gray value. And,

[0167] As described above, embodiments of the present invention can provide a display device and a driving method thereof that can sense the characteristic information of pixels according to the positions of each pixel and accurately compensate the characteristic information according to the positions of each pixel.

[0168] As mentioned above, although the embodiments of the present invention have been described with reference to the accompanying drawings, those of ordinary skill in the technical field to which the present invention pertains will understand that the present invention can be implemented in other specific forms without changing the technical idea or essential features. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive.

Claims

1. A display device, comprising: A display portion including pixels divided into a plurality of blocks; a sensing unit, measuring a sensing current according to the pixel and outputting a sensing current value; as well as a compensation unit that calculates a position-specific degradation weight value for the pixel based on the sensed current value and a preset reference current value, accumulates the degree of degradation reflecting the degradation weight value and updates the degradation accumulation value each time the sensed current is measured, and reflects the updated degradation accumulation value in an input grayscale value input from the outside to generate an output grayscale value. wherein the number of blocks is less than or equal to the number of pixels, The compensation unit obtains a first block degradation degree corresponding to a first block and a second block degradation degree corresponding to at least one second block adjacent to the first block, calculates a difference value between the first block degradation degree and the second block degradation degree, and if the difference value is greater than a preset reference value, stores information about the first block, confirms whether the display device is turned off, and if the display device is turned off, updates the block degradation cumulative value corresponding to the first block.

2. The display device according to claim 1, wherein The sensing section measures a sense current generated by each of a plurality of pixels included in a block, and calculates a block current value for each of the blocks based on the measured sense current.

3. The display device according to claim 2, wherein: The compensation unit calculates a block degradation weight value corresponding to the block based on the block current value and the reference current value, reflects the block degradation weight value in the block degradation degree corresponding to the block, accumulates the block degradation degree to update the block degradation cumulative value, and reflects the updated block degradation cumulative value in the input grayscale value to generate a block output grayscale value for the block.

4. The display device according to claim 1, wherein If the display device is turned off, a block current value corresponding to the stored first block is calculated, a block degradation weight value is calculated based on the block current value corresponding to the first block and the reference current value, and the first block degradation degree reflecting the block degradation weight value is accumulated to update the block degradation cumulative value.

5. The display device according to claim 1, wherein The pixels include: a first transistor including a gate electrode connected to the first node, a first electrode connected to the first power supply, and a second electrode connected to the second node; a second transistor comprising a gate electrode connected to the first scan line, a first electrode connected to the data line, and a second electrode connected to the first node; a third transistor including a gate electrode connected to the second scan line, a first electrode connected to the second node, and a second electrode connected to the sensing line; and The light emitting diode includes an anode connected to the second node and a cathode connected to a second power source.

6. The display device according to claim 5, wherein: When measuring the sensing current, a voltage corresponding to reference grayscale data is applied to the first node. The reference grayscale data is data in which the characteristics of the first transistor are compensated.

7. The display device according to claim 6, wherein: The characteristic includes at least one of a threshold voltage and a mobility of the first transistor.

8. The display device according to claim 5, wherein: The voltage of the second power supply is set to be greater than the voltage of the first power supply during the measurement of the sensing current.

9. The display device according to claim 1, wherein The degradation cumulative value increases as the degradation degree increases. The degradation degree increases as the degradation weight value increases, The degradation weight value is determined based on a ratio of the sensing current value to the reference current value.

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