Display device performing image sticking compensation, and method of compensating image sticking in a display device

Abstract

The display device includes a display panel, a data driver, a scan driver, and a controller. The controller includes a residual image compensation block having a volatile lifetime memory and an internal lifetime memory. The residual image compensation block calculates accumulated degradation amounts based on input image data, writes the accumulated degradation amounts to the volatile lifetime memory, writes backup accumulated degradation amounts to the internal lifetime memory, compares the accumulated degradation amounts read from the volatile lifetime memory with the accumulated degradation amounts calculated by accumulating the current degradation amounts, and compensates the input image data by selectively using the accumulated degradation amounts read from the volatile lifetime memory or the backup accumulated degradation amounts stored in the internal lifetime memory according to the result of the comparison.

Description

Technology Field

[0001] The present invention relates to a display device, and more specifically, to a display device that performs afterimage compensation and a method for compensating afterimages of a display device. Background Technology

[0002] As the driving time of a display device, such as an organic light-emitting display, accumulates, the driving transistors and / or organic light-emitting diodes of the pixels included in the display device may degrade. When the pixels degrade, they fail to emit light at a desired brightness, and image sticking may be visible on the display device. To reduce or eliminate image sticking caused by such pixel degradation, the display device may calculate the accumulated degradation amounts of the pixels and perform an image sticking compensation operation to compensate for image data based on the accumulated degradation amounts. However, if a write or read operation for the lifetime memory where the accumulated degradation amounts are stored is not performed normally due to electrostatic discharge (ESD), memory access failure, hardware failure, etc., the image sticking compensation operation may not be performed accurately, the image data may not be compensated accurately, and the image quality of the display device may degrade. The problem to be solved

[0003] One objective of the present invention is to provide a display device capable of accurately performing afterimage compensation operation.

[0004] Another objective of the present invention is to provide a method for compensating afterimages of a display device that can accurately perform afterimage compensation operations.

[0005] However, the problem to be solved by the present invention is not limited to the problem mentioned above, and may be expanded in various ways without departing from the spirit and scope of the present invention. means of solving the problem

[0006] To achieve one objective of the present invention, a display device according to embodiments of the present invention comprises a display panel including a plurality of pixels, a data driver providing data signals to the plurality of pixels, a scan driver providing scan signals to the plurality of pixels, a volatile lifetime memory that controls the data driver and the scan driver and stores accumulated degradation amounts for the plurality of pixels, and an internal lifetime memory that stores backup accumulated degradation amounts generated based on the accumulated degradation amounts, and a controller that compensates input image data by selectively using the accumulated degradation amounts of the volatile lifetime memory or the backup accumulated degradation amounts of the internal lifetime memory.

[0007] In one embodiment, the controller further includes a residual image compensation block for compensating the input image data, the volatile lifetime memory is located outside the residual image compensation block, and the internal lifetime memory is located inside the residual image compensation block. The residual image compensation block calculates current degradation amounts based on the input image data in the current frame, calculates accumulated degradation amounts by accumulating the current degradation amounts, writes the accumulated degradation amounts to the volatile lifetime memory, generates backup accumulated degradation amounts based on the accumulated degradation amounts, writes the backup accumulated degradation amounts to the internal lifetime memory, reads the accumulated degradation amounts from the volatile lifetime memory in the next frame, compares the accumulated degradation amounts read from the volatile lifetime memory with the accumulated degradation amounts calculated in the current frame, and if the accumulated degradation amounts read from the volatile lifetime memory are the same as the accumulated degradation amounts calculated in the current frame, compensates the input image data in the next frame using the accumulated degradation amounts read from the volatile lifetime memory, and the volatile lifetime If the accumulated degradation amounts read from memory differ from the accumulated degradation amounts calculated in the current frame, the input image data in the next frame can be compensated using the backup accumulated degradation amounts stored in the internal life memory.

[0008] In one embodiment, the afterimage compensation block calculates a first checksum of the accumulated degradation amounts read from the volatile lifetime memory, calculates a second checksum of the accumulated degradation amounts calculated by accumulating the current degradation amounts, and compares the first checksum with the second checksum to determine whether the accumulated degradation amounts read from the volatile lifetime memory are the same as the accumulated degradation amounts calculated by accumulating the current degradation amounts.

[0009] In one embodiment, the accumulated degradation amounts are calculated in units of a first pixel block, and the backup accumulated degradation amounts are calculated in units of a second pixel block, and the size of the second pixel block may be larger than the size of the first pixel block.

[0010] In one embodiment, the afterimage compensation block comprises: an internal lifespan memory; a current lifespan calculator that divides the input image data in the current frame into a plurality of block image data for a plurality of first pixel blocks and calculates the current degradation amounts for the plurality of first pixel blocks based on the plurality of block image data; a cumulative lifespan calculator that calculates the cumulative degradation amounts for the plurality of first pixel blocks by accumulating the current degradation amounts for the plurality of first pixel blocks and writes the cumulative degradation amounts for the plurality of first pixel blocks to the volatile lifespan memory, generates the backup cumulative degradation amounts for a plurality of second pixel blocks by merging the cumulative degradation amounts for the plurality of first pixel blocks, and writes the backup cumulative degradation amounts for the plurality of second pixel blocks to the internal lifespan memory; a data compensator that reads the cumulative degradation amounts for the plurality of first pixel blocks from the volatile lifespan memory; and compares the cumulative degradation amounts read by the data compensator with the cumulative degradation amounts calculated by the cumulative lifespan calculator, and the cumulative It may include a life comparator that generates a fail flag signal having a first level when the degradation amounts are the same as the accumulated degradation amounts calculated by the accumulated life calculator, and generates the fail flag signal having a second level when the accumulated degradation amounts read by the data comparator are different from the accumulated degradation amounts calculated by the accumulated life calculator.The data compensator can compensate the input image data using the accumulated degradation amounts for the plurality of first pixel blocks in response to the fail flag signal having the first level, and read the backup accumulated degradation amounts for the plurality of second pixel blocks from the internal life memory in response to the fail flag signal having the second level, and compensate the input image data using the backup accumulated degradation amounts for the plurality of second pixel blocks.

[0011] In one embodiment, the size of each of the plurality of second pixel blocks may be larger than the size of each of the plurality of first pixel blocks.

[0012] In one embodiment, the life comparator may calculate a first checksum of the accumulated deterioration amounts read by the data compensator, calculate a second checksum of the accumulated deterioration amounts calculated by the accumulated life calculator, and generate the fail flag signal by comparing the first checksum and the second checksum.

[0013] In one embodiment, the afterimage compensation block may further include a weighting determiner that determines block degradation weights for the plurality of first pixel blocks based on at least one of the driving frequency of the display panel, the temperature of the display panel, and the locations of the plurality of first pixel blocks.

[0014] In one embodiment, the current life calculator can calculate the current degradation amounts for the plurality of first pixel blocks by applying the block degradation weights to the plurality of block image data.

[0015] In one embodiment, the controller may further include a pre-scaling block that receives the accumulated degradation amounts from the afterimage compensation block, determines a pre-scaling coefficient based on the maximum accumulated degradation amount among the accumulated degradation amounts, generates pre-scaled input image data by applying the pre-scaling coefficient to the input image data, and provides the pre-scaled input image data to the afterimage compensation block.

[0016] In one embodiment, the display device may further include a non-volatile lifetime memory for storing the accumulated degradation amounts while the display device is powered off.

[0017] In one embodiment, the controller can periodically write the accumulated degradation amounts stored in the volatile lifetime memory to the non-volatile lifetime memory.

[0018] To achieve another objective of the present invention, in a method for compensating afterimages of a display device according to embodiments of the present invention, current degradation amounts are calculated based on input image data in a current frame, and accumulated degradation amounts are calculated by accumulating the current degradation amounts; the accumulated degradation amounts are written to a volatile lifetime memory located outside the afterimage compensation block; backup accumulated degradation amounts are generated based on the accumulated degradation amounts; the backup accumulated degradation amounts are written to an internal lifetime memory of the afterimage compensation block; the accumulated degradation amounts are read from the volatile lifetime memory in the next frame; the accumulated degradation amounts read from the volatile lifetime memory are compared with the accumulated degradation amounts calculated by accumulating the current degradation amounts; and according to the result of the comparison, the input image data in the next frame is compensated by selectively using the accumulated degradation amounts read from the volatile lifetime memory or the backup accumulated degradation amounts stored in the internal lifetime memory.

[0019] In one embodiment, if the accumulated degradation amounts read from the volatile lifetime memory are the same as the accumulated degradation amounts calculated by accumulating the current degradation amounts, the input image data in the next frame is compensated using the accumulated degradation amounts read from the volatile lifetime memory, and if the accumulated degradation amounts read from the volatile lifetime memory are different from the accumulated degradation amounts calculated by accumulating the current degradation amounts, the input image data in the next frame can be compensated using the backup accumulated degradation amounts stored in the internal lifetime memory.

[0020] In one embodiment, a first checksum of the accumulated degradation amounts read from the volatile lifetime memory is calculated and a second checksum of the accumulated degradation amounts calculated by accumulating the current degradation amounts is calculated so as to compare the accumulated degradation amounts read from the volatile lifetime memory with the accumulated degradation amounts calculated by accumulating the current degradation amounts, and by comparing the first checksum and the second checksum, it can be determined whether the accumulated degradation amounts read from the volatile lifetime memory are the same as the accumulated degradation amounts calculated by accumulating the current degradation amounts.

[0021] In one embodiment, the accumulated degradation amounts are calculated in units of a first pixel block, and the backup accumulated degradation amounts are calculated in units of a second pixel block, and the size of the second pixel block may be larger than the size of the first pixel block.

[0022] In one embodiment, the input image data in the current frame is divided into a plurality of block image data for a plurality of first pixel blocks, block degradation weights for the plurality of first pixel blocks are determined based on at least one of the driving frequency of the display panel, the temperature of the display panel, and the positions of the plurality of first pixel blocks, and the current degradation amount for the plurality of first pixel blocks can be calculated by applying the block degradation weights to the plurality of block image data.

[0023] In one embodiment, the accumulated degradation amounts for the plurality of first pixel blocks may be merged to generate the backup accumulated degradation amounts for the plurality of second pixel blocks.

[0024] In one embodiment, the accumulated degradation amounts stored in the volatile lifetime memory can be periodically written to the non-volatile lifetime memory.

[0025] In one embodiment, a pre-scaling coefficient is determined based on the maximum accumulated degradation amount among the accumulated degradation amounts, and the pre-scaling coefficient can be applied to the input image data. Effects of the invention

[0026] In a display device and a method for compensating afterimages of a display device according to embodiments of the present invention, an afterimage compensation block has an internal lifetime memory, calculates accumulated degradation amounts by accumulating current degradation amounts, reads the accumulated degradation amounts from a volatile lifetime memory located outside the afterimage compensation block, compares the calculated accumulated degradation amounts with the read accumulated degradation amounts, and can compensate input image data by selectively using the read accumulated degradation amounts or backup accumulated degradation amounts stored in the internal lifetime memory according to the result of the comparison. Accordingly, even if a write operation or a read operation for a volatile / non-volatile lifetime memory located outside the afterimage compensation block is not performed normally due to electrostatic discharge (ESD), memory access failure, hardware failure, etc., an afterimage compensation operation can be performed normally by using the backup accumulated degradation amounts of the internal lifetime memory.

[0027] However, the effects of the present invention are not limited to the effects mentioned above and may be extended in various ways without departing from the spirit and scope of the present invention. Brief explanation of the drawing

[0028] FIG. 1 is a block diagram showing a display device according to embodiments of the present invention. FIG. 2 is a circuit diagram showing an example of a pixel included in a display device according to embodiments of the present invention. FIG. 3 is a block diagram showing an example of a residual image compensation block according to embodiments of the present invention. FIG. 4 is a timing diagram for explaining an example of the operation of a residual image compensation block according to embodiments of the present invention. FIG. 5 is a diagram illustrating an example of a plurality of first pixel blocks in which current degradation amounts and accumulated degradation amounts are calculated. FIG. 6 is a diagram illustrating an example of multiple second pixel blocks in which backup accumulated degradation amounts are calculated. FIG. 7 is a flowchart illustrating a method for compensating afterimages of a display device according to embodiments of the present invention. FIG. 8 is a block diagram showing a display device according to embodiments of the present invention. FIG. 9 is a flowchart illustrating a method for compensating afterimages of a display device according to embodiments of the present invention. FIG. 10 is a block diagram showing an electronic device including a display device according to embodiments of the present invention. Specific details for implementing the invention

[0029] Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the attached drawings. Identical components in the drawings are denoted by the same reference numerals, and redundant descriptions of identical components are omitted.

[0030] FIG. 1 is a block diagram showing a display device according to embodiments of the present invention, FIG. 2 is a circuit diagram showing an example of a pixel included in a display device according to embodiments of the present invention, FIG. 3 is a block diagram showing an example of a residual image compensation block according to embodiments of the present invention, FIG. 4 is a timing diagram for explaining an example of the operation of a residual image compensation block according to embodiments of the present invention, FIG. 5 is a diagram for explaining an example of a plurality of first pixel blocks in which current degradation amounts and accumulated degradation amounts are calculated, and FIG. 6 is a diagram for explaining an example of a plurality of second pixel blocks in which backup accumulated degradation amounts are calculated.

[0031] Referring to FIG. 1, a display device (100) according to embodiments of the present invention may include a display panel (110) including a plurality of pixels (PX), a data driver (120) that provides data signals (DS) to the plurality of pixels (PX), a scan driver (130) that provides scan signals (SS) to the plurality of pixels (PX), and a controller (150) that controls the data driver (120) and the scan driver (130). In one embodiment, the display device (100) may further include a non-volatile lifetime memory (140).

[0032] A display panel (110) may include a plurality of data lines, a plurality of scan lines, and a plurality of pixels (PX) connected to the plurality of data lines and the plurality of scan lines. In one embodiment, each pixel (PX) includes an Organic Light Emitting Diode (OLED), and the display panel (110) may be an OLED display panel.

[0033] For example, as illustrated in FIG. 2, each pixel (PX) may include a switching transistor (TSW) that transmits a data signal (DS) of a data line to a storage capacitor (CST) in response to a scan signal (SC) of the scan line, a storage capacitor (CST) that stores the data signal (DS) transmitted by the switching transistor (TSW), a driving transistor (TDR) that generates a driving current based on the data signal (DS) stored in the storage capacitor (CST), and an organic light-emitting diode (EL) that emits light based on the driving current generated by the driving transistor (TDR). In one embodiment, as illustrated in FIG. 2, the switching transistor (TSW) and the driving transistor (TDR) may be implemented as NMOS transistors, but are not limited thereto.

[0034] The pixel (PX) according to embodiments of the present invention may have various configurations, not limited to the exemplary configuration shown in FIG. 2. In addition, in other embodiments, the display panel (110) may be an inorganic light-emitting diode display panel or a quantum dot light-emitting diode display panel, a Liquid Crystal Display (LCD) panel, or any other suitable display panel.

[0035] The data driver (120) can generate data signals (DS) based on output image data (ODAT) and a data control signal (DCTRL) received from the controller (150), and provide the data signals (DS) to a plurality of pixels (PX) through the plurality of data lines. In one embodiment, the data control signal (DCTRL) may include, but is not limited to, an output data enable signal, a horizontal start signal, and a load signal. In one embodiment, the data driver (120) may be implemented in one or more integrated circuits separate from the integrated circuit in which the controller (150) is implemented. In another embodiment, the data driver (120) and the controller (150) may be implemented in a single integrated circuit, and such an integrated circuit may be called a Timing controller Embedded Data driver (TED) IC.

[0036] The scan driver (130) generates scan signals (SS) based on a scan control signal (SCTRL) received from the controller (150) and can sequentially provide the scan signals (SS) to a plurality of pixels (PX) in row units through the plurality of scan lines. In one embodiment, the scan control signal (SCTRL) may include a scan start signal and a scan clock signal, but is not limited thereto. In one embodiment, the scan driver (130) may be integrated or formed in the periphery of the display panel (110). In another embodiment, the scan driver (130) may be implemented with one or more integrated circuits.

[0037] The non-volatile lifetime memory (140) stores accumulated degradation amounts for pixels (PX) of the display panel (110) and can maintain said accumulated degradation amounts even while the display device (100) is powered off. In one embodiment, the display panel (110) is divided into a plurality of first pixel blocks (BL1), each containing a plurality of pixels (PX), as shown in FIG. 5, and the non-volatile lifetime memory (140) can store said accumulated degradation amounts for each of the plurality of first pixel blocks (BL1). Also, in one embodiment, when the display device (100) is powered on, the controller (150) can read said accumulated degradation amounts stored in the non-volatile lifetime memory (140) and write or store them in the volatile lifetime memory (170) of the controller (150). The afterimage compensation block (200) of the controller (150) reads the accumulated degradation amounts from the volatile lifetime memory (170), updates the accumulated degradation amounts every frame while the display device (100) is running, and can write the updated accumulated degradation amounts to the volatile lifetime memory (170) every frame. Additionally, the controller (150) can periodically write the accumulated degradation amounts stored in the volatile lifetime memory (170) to the non-volatile lifetime memory (140). For example, the accumulated degradation amounts of the volatile lifetime memory (170) may be written to the non-volatile lifetime memory (140) every approximately 5 to 10 minutes, but the period of the write operation to the non-volatile lifetime memory (140) is not limited thereto. In this way, the display device (100) can use a non-volatile lifetime memory (140) to calculate and store the accumulated degradation amounts for each of the plurality of first pixel blocks (BL1) from the time of manufacture of the display device (100) to the present time. In one embodiment, the non-volatile lifetime memory (140) may be implemented as a flash memory, but is not limited thereto.

[0038] A controller (150) (e.g., a timing controller (TCON)) may receive input image data (IDAT) and a control signal (CTRL) from an external host processor (e.g., a graphic processing unit (GPU) or a graphics card). In one embodiment, the input image data (IDAT) may be RGB image data including red image data, green image data, and blue image data. In one embodiment, the control signal (CTRL) may include, but is not limited to, a vertical synchronization signal, a horizontal synchronization signal, an input data enable signal, a master clock signal, etc. The controller (150) may generate output image data (ODAT) by compensating the input image data (IDAT) based on the accumulated degradation amounts. Additionally, the controller (150) can control the operation of the data driver (120) by providing output image data (ODAT) and a data control signal (DCTRL) to the data driver (120), and control the operation of the scan driver (130) by providing a scan control signal (SCTRL) to the scan driver (130).

[0039] In a display device (100) according to embodiments of the present invention, to perform an image sticking compensation operation, the controller (150) may include a volatile lifetime memory (170) and an image sticking compensation block (200).

[0040] The volatile lifetime memory (170) can store the accumulated degradation amounts read from the non-volatile lifetime memory (140) when the display device (100) is powered on, and provide the read accumulated degradation amounts to the afterimage compensation block (200). Additionally, the volatile lifetime memory (170) can receive and store the accumulated degradation amounts updated every frame from the afterimage compensation block (200) while the display device (100) is operating, and provide the stored accumulated degradation amounts to the afterimage compensation block (200) every frame. Additionally, in one embodiment, the accumulated degradation amounts of the volatile lifetime memory (170) can be periodically written to the non-volatile lifetime memory (140). In one embodiment, the volatile lifetime memory (170) can be implemented as Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), Mobile DRAM, etc., but is not limited thereto.

[0041] The afterimage compensation block (200) may include an internal lifetime memory (210). In the current frame, the afterimage compensation block (200) may calculate current degradation amounts based on input image data (IDAT), calculate the accumulated degradation amounts by accumulating the current degradation amounts (and the accumulated degradation amounts read from the non-volatile lifetime memory (140) through the volatile lifetime memory (170), write the accumulated degradation amounts to the volatile lifetime memory (170), generate backup accumulated degradation amounts based on the accumulated degradation amounts, and write the backup accumulated degradation amounts to the internal lifetime memory (210). Additionally, in the next frame, the afterimage compensation block (200) reads the accumulated degradation amounts from the volatile lifetime memory (170), compares the accumulated degradation amounts read from the volatile lifetime memory (170) with the accumulated degradation amounts calculated by accumulating the current degradation amounts, and, depending on the result of the comparison, can compensate the input image data (IDAT) in the next frame by selectively using the accumulated degradation amounts read from the volatile lifetime memory (170) or the backup accumulated degradation amounts stored in the internal lifetime memory (210). In one embodiment, to perform this operation, as shown in FIG. 3, the afterimage compensation block (200) may include an internal lifetime memory (210), a current lifetime calculator (220), an accumulated lifetime calculator (230), a data compensator (240), and a lifetime comparator (250). In one embodiment, the afterimage compensation block (200) may further include a weighting determiner (260).

[0042] The current life calculator (220) can divide the input image data (IDAT) in the current frame into multiple block image data for multiple first pixel blocks (BL1) shown in FIG. 5, and calculate the current degradation amount (CDA) for the multiple first pixel blocks (BL1) based on the multiple block image data. For example, each first pixel block (BL1) may have a size of 4 pixels (PX) * 4 pixels (PX), a size of 8 pixels (PX) * 8 pixels (PX), etc., but is not limited thereto. In one embodiment, as the block image data for each first pixel block (BL1) increases, the current degradation amount (CDA) for the first pixel block (BL1) may increase. For example, the current life calculator (220) can calculate the current degradation amount (CDA) for the first pixel block (BL1) by summing the pixel image data (e.g., 16, 64, etc.) included in the block image data for the first pixel block (BL1), but is not limited thereto.

[0043] In one embodiment, the current life calculator (220) receives block degradation weights (BDW) for a plurality of first pixel blocks (BL1) from the weighting determiner (260) and can calculate the current degradation amount (CDA) for the plurality of first pixel blocks (BL1) by applying the block degradation weights (BDW) to the plurality of block image data. In one embodiment, the weighting determiner (260) can determine the block degradation weights (BDW) for the plurality of first pixel blocks (BL1) based on at least one of the driving frequency of the display panel (110), the temperature of the display panel (110), and the locations of the plurality of first pixel blocks (BL1). For example, the weighting determiner (260) can increase the block degradation weights (BDW) as the driving frequency of the display panel (110) increases. Additionally, for example, the weighting determiner (260) includes a weighting lookup table that stores block degradation weights (BDW) according to the temperature of the display panel (110) and the positions of a plurality of first pixel blocks (BL1), and can determine the block degradation weights (BDW) for a plurality of first pixel blocks (BL1) using the weighting lookup table. Additionally, the current life calculator (220) calculates an intermediate current degradation amount for the first pixel block (BL1) by summing the pixel image data for each first pixel block (BL1), calculates a final current degradation amount for the first pixel block (BL1) by multiplying the intermediate current degradation amount by the block degradation weight (BDW) for the first pixel block (BL1), and can output the final current degradation amount as the current degradation amount (CDA) for the first pixel block (BL1).

[0044] The cumulative life calculator (230) can calculate the cumulative degradation amounts (CADA) for a plurality of first pixel blocks (BL1) by accumulating the current degradation amounts (CDA) for a plurality of first pixel blocks (BL1). In one embodiment, the cumulative life calculator (230) can calculate the cumulative degradation amounts (CADA) from the time of manufacture of the display panel (110) to each of the frames by reading the previous cumulative degradation amounts from the non-volatile life memory (140) through the volatile life memory (170) when the display device (100) is powered on, and adding the current degradation amounts (CDA) in each frame to the previous cumulative degradation amounts during the current operation of the display device (100).

[0045] The cumulative life calculator (230) can write cumulative degradation amounts (CADA) for a plurality of first pixel blocks (BL1) to the volatile life memory (170). In one embodiment, the cumulative degradation amounts (CADA) stored in the volatile life memory (170) can be read by the data compensator (240) to compensate for input image data (IDAT) in the next frame, and / or read again by the cumulative life calculator (230) to calculate the cumulative degradation amounts (CADA) in the next frame.

[0046] Additionally, the cumulative life calculator (230) can generate backup cumulative degradation amounts (BADA) for a plurality of second pixel blocks (BL2) shown in FIG. 6 based on cumulative degradation amounts (CADA) for a plurality of first pixel blocks (BL1), and write the backup cumulative degradation amounts (BADA) for a plurality of second pixel blocks (BL2) to the internal life memory (210). In one embodiment, as shown in FIG. 5 and FIG. 6, the size of each second pixel block (BL2) may be larger than the size of each first pixel block (BL1). For example, each first pixel block (BL1) may have a size of 4 pixels (PX) * 4 pixels (PX), a size of 8 pixels (PX) * 8 pixels (PX), etc., but is not limited thereto. Additionally, for example, the display panel (110) is divided into 18*16 second pixel blocks (BL2), and each second pixel block (BL2) may have a size of 240 pixels (PX) * 120 pixels (PX), but is not limited thereto. Thus, the accumulated degradation amounts (CADA) are calculated in units of the first pixel block (BL1), and the backup accumulated degradation amounts (BADA) can be calculated in units of the second pixel block (BL2) having a size larger than that of the first pixel block (BL1), and thus the data size of the backup accumulated degradation amounts (BADA) may be smaller than the data size of the accumulated degradation amounts (CADA). Accordingly, the internal lifespan memory (210) of the afterimage compensation block (200) may have a size smaller than the volatile lifespan memory (170) and may be suitable for being formed inside the afterimage compensation block (200). In one embodiment, to generate backup accumulated degradation amounts (BADA) having a data size smaller than the accumulated degradation amounts (CADA), the accumulated life calculator (230) can generate backup accumulated degradation amounts (BADA) for a plurality of second pixel blocks (BL2) by merging the accumulated degradation amounts (CADA) for a plurality of first pixel blocks (BL1).

[0047] The data compensator (240) can read the accumulated degradation amounts (RADA) for a plurality of first pixel blocks (BL1) from the volatile lifetime memory (170) in the initial period of the next frame. Additionally, in the initial period of the next frame, the lifetime comparator (250) can compare the accumulated degradation amounts (RADA) in the current frame (i.e., in the frame immediately preceding the next frame) read by the data compensator (240) with the accumulated degradation amounts (CADA) in the current frame calculated by the accumulated lifetime calculator (230). In one embodiment, the lifetime comparator (250) calculates a first checksum of accumulated degradation amounts (RADA) read from the volatile lifetime memory (170), calculates a second checksum of accumulated degradation amounts (CADA) calculated by the accumulated lifetime calculator (230), and can determine whether the read accumulated degradation amounts (RADA) are the same as the calculated accumulated degradation amounts (CADA) by comparing the first checksum and the second checksum. Additionally, the lifetime comparator (250) can generate a fail flag signal (FFS) by comparing the first checksum and the second checksum. For example, the life comparator (250) can generate a fail flag signal (FFS) having a first level (e.g., high level) when the first checksum and the second checksum are the same, i.e., when the read accumulated deterioration amounts (RADA) are the same as the calculated accumulated deterioration amounts (CADA), and generate a fail flag signal (FFS) having a second level (e.g., low level) when the first checksum and the second checksum are different, i.e., when the read accumulated deterioration amounts (RADA) are different from the calculated accumulated deterioration amounts (CADA).

[0048] The data compensator (240) can compensate the input image data (IDAT) using the accumulated degradation amounts (RADA) for a plurality of first pixel blocks (BL1) read from the volatile lifetime memory (170) when the read accumulated degradation amounts (RADA) are the same as the calculated accumulated degradation amounts (CADA). In one embodiment, the data compensator (240) includes a lifetime compensation lookup table that stores compensation coefficients according to grayscale levels and degradation amounts, and obtains the compensation coefficients for a plurality of first pixel blocks (BL1) corresponding to the grayscale levels and read accumulated degradation amounts (RADA) represented by the input image data (IDAT) from the lifetime compensation lookup table, and can generate output image data (ODAT) by applying the compensation coefficients for a plurality of first pixel blocks (BL1) to the input image data (IDAT). Additionally, the data compensator (240) can compensate the input image data (IDAT) using backup accumulated degradation amounts (BADA) stored in the internal lifetime memory (210) when the read accumulated degradation amounts (RADA) are different from the calculated accumulated degradation amounts (CADA). For example, the data compensator (240) can obtain the compensation coefficients for a plurality of second pixel blocks (BL2) corresponding to the grayscale levels represented by the input image data (IDAT) and the backup accumulated degradation amounts (BADA) from the lifetime compensation lookup table, and generate output image data (ODAT) by applying the compensation coefficients for the plurality of second pixel blocks (BL2) to the input image data (IDAT).

[0049] In one embodiment, the data compensator (240) receives a fail flag signal (FFS) from the life comparator (250) and, in response to the fail flag signal (FFS) having the first level, can compensate the input image data (IDAT) using accumulated degradation amounts (RADA) for a plurality of first pixel blocks (BL1). Additionally, in response to the fail flag signal (FFS) having the second level, the data compensator (240) reads backup accumulated degradation amounts (BADA) for a plurality of second pixel blocks (BL2) from the internal life memory (210) and can compensate the input image data (IDAT) using the backup accumulated degradation amounts (BADA) for a plurality of second pixel blocks (BL2). Meanwhile, the size of each second pixel block (BL2) may be larger than the size of each first pixel block (BL1), and therefore, the afterimage compensation operation using backup accumulated degradation amounts (BADA) may not be as fine as the afterimage compensation operation using accumulated degradation amounts (RADA). However, since the afterimage compensation operation using backup accumulated degradation amounts (BADA) is performed only in the section where the fail flag signal (FFS) has the first level, that is, only in the section where the write operation or read operation for the non-volatile lifetime memory (140) and / or volatile lifetime memory (170) is not performed normally due to electrostatic discharge, memory access failure, hardware failure, etc., the image quality of the display device (100) may not be excessively degraded.

[0050] Hereinafter, an example of the operation of the afterimage compensation block (200) is described with reference to FIGS. 1 to 6.

[0051] Referring to FIGS. 1 to 6, in the Nth frame (FN) (N is an integer greater than or equal to 2), the current life calculator (220) calculates the current degradation amounts (CDAN) in the Nth frame (FN) for a plurality of first pixel blocks (BL1) based on the input image data (IDAT) in the Nth frame (FN), and the cumulative life calculator (230) can calculate the cumulative degradation amounts (ADAN) in the Nth frame (FN) for a plurality of first pixel blocks (BL1) by adding the current degradation amounts (CDAN) in the Nth frame (FN) to the cumulative degradation amounts (ADAN-1) in the N-1 frame (FN-1). In one example, the cumulative life calculator (230) can store the cumulative degradation amounts (ADAN-1) in the N-1 frame (FN-1) and calculate the cumulative degradation amounts (ADAN) in the N-N frame (FN) by adding the current degradation amounts (CDAN) in the N-N frame (FN) to the cumulative degradation amounts (ADAN) in the N-1 frame (FN-1). In another example, the cumulative life calculator (230) can read the cumulative degradation amounts (ADAN-1) in the N-1 frame (FN-1) from the volatile life memory (170) at the start of the N-N frame (FN) and calculate the cumulative degradation amounts (ADAN) in the N-N frame (FN) by adding the current degradation amounts (CDAN) in the N-N frame (FN) to the cumulative degradation amounts (ADAN) in the N-1 frame (FN-1). The cumulative life calculator (230) can write the cumulative degradation amounts (ADAN) in the Nth frame (FN) for a plurality of first pixel blocks (BL1) to the volatile life memory (170). Additionally, the cumulative life calculator (230) can generate backup cumulative degradation amounts (BADAN) in the Nth frame (FN) for a plurality of second pixel blocks (BL2) based on the cumulative degradation amounts (ADAN) in the Nth frame (FN) for a plurality of first pixel blocks (BL1), and write the backup cumulative degradation amounts (BADAN) in the Nth frame (FN) for a plurality of second pixel blocks (BL2) to the internal life memory (210).

[0052] In the initial period of the N+1 frame (FN+1), the data compensator (240) reads the accumulated degradation amounts (ADAN) in the Nth frame (FN) from the volatile lifetime memory (170), and the lifetime comparator (250) can compare the accumulated degradation amounts (ADAN) in the Nth frame (FN) read by the data compensator (240) with the accumulated degradation amounts (ADAN) in the Nth frame (FN) calculated by the cumulative lifetime calculator (230). If the accumulated degradation amounts (ADAN) in the Nth frame (FN) read by the data compensator (240) are the same as the accumulated degradation amounts (ADAN) in the Nth frame (FN) calculated by the accumulated lifespan calculator (230), the data compensator (240) can compensate the input image data (IDAT) of the N+1 frame (FN+1) using the accumulated degradation amounts (ADAN) in the Nth frame (FN) for a plurality of first pixel blocks (BL1) read from the volatile lifespan memory (170). If the accumulated degradation amounts (ADAN) in the Nth frame (FN) read by the data compensator (240) are different from the accumulated degradation amounts (ADAN) in the Nth frame (FN) calculated by the accumulated lifespan calculator (230), the data compensator (240) reads the backup accumulated degradation amounts (BADAN) in the Nth frame (FN) for a plurality of second pixel blocks (BL2) from the internal lifespan memory (210), and can compensate the input image data (IDAT) using the backup accumulated degradation amounts (BADAN) in the Nth frame (FN) for a plurality of second pixel blocks (BL2).Additionally, in the N+1 frame (FN+1), the current life calculator (220) calculates the current degradation amounts (CDAN+1) in the N+1 frame (FN+1), and the cumulative life calculator (230) calculates the cumulative degradation amounts (ADAN+1) in the N+1 frame (FN+1) by adding the current degradation amounts (CDAN+1) in the N+1 frame (FN+1) to the cumulative degradation amounts (ADAN) in the N frame (FN), writes the cumulative degradation amounts (ADAN+1) in the N+1 frame (FN+1) to the volatile life memory (170), generates backup cumulative degradation amounts (BADAN+1) in the N+1 frame (FN+1), and writes the backup cumulative degradation amounts (BADAN+1) in the N+1 frame (FN+1) to the internal life memory (210).

[0053] Meanwhile, in a conventional display device that performs afterimage compensation, if a write operation or read operation for a volatile lifetime memory (170) and / or a non-volatile lifetime memory (140) is not performed normally due to electrostatic discharge (ESD), memory access failure, hardware failure, etc., the input image data (IDAT) is compensated based on inaccurate accumulated degradation amounts, and the image quality of the conventional display device may be degraded. However, in the display device (100) according to embodiments of the present invention, the afterimage compensation block (200) has an internal lifespan memory (210), calculates the accumulated degradation amounts (CADA) by accumulating the current degradation amounts (CDA), reads the accumulated degradation amounts (RADA) from a volatile lifespan memory (170) located outside the afterimage compensation block (200), compares the calculated accumulated degradation amounts (CADA) with the read accumulated degradation amounts (RADA), and can compensate the input image data (IDAT) by selectively using the read accumulated degradation amounts (RADA) or the backup accumulated degradation amounts (BADA) stored in the internal lifespan memory (210) according to the result of the comparison. Accordingly, in the display device (100) according to the embodiments of the present invention, even if a write operation or a read operation for volatile and / or non-volatile lifetime memories (140, 170) located outside the residual image compensation block (200) is not performed normally due to ESD, memory access failure, hardware failure, etc., a residual image compensation operation can be performed normally using backup accumulated degradation amounts (BADA) of the internal lifetime memory (210).

[0054] FIG. 7 is a flowchart illustrating a method for compensating afterimages of a display device according to embodiments of the present invention.

[0055] Referring to FIGS. 1, FIGS. 3 and FIGS. 7, in the current frame, the current life calculator (220) of the afterimage compensation block (200) can calculate the current degradation amounts (CDA) based on the input image data (IDAT) (S310). In one embodiment, the current life calculator (220) divides the input image data (IDAT) in the current frame into a plurality of block image data for a plurality of first pixel blocks, determines block degradation weights for the plurality of first pixel blocks based on at least one of the driving frequency of the display panel (110), the temperature of the display panel (110), and the positions of the plurality of first pixel blocks, and calculates the current degradation amounts (CDA) for the plurality of first pixel blocks by applying the block degradation weights to the plurality of block image data.

[0056] The cumulative life calculator (230) of the afterimage compensation block (200) can calculate the cumulative degradation amounts (CADA) by accumulating the current degradation amounts (CDA) (S320). The cumulative life calculator (230) can write the cumulative degradation amounts (CADA) to a volatile life memory (170) located outside the afterimage compensation block (200) (S330). In one embodiment, the cumulative degradation amounts (CADA) stored in the volatile life memory (170) can be periodically written to a non-volatile life memory (140).

[0057] Additionally, the cumulative life calculator (230) can generate backup cumulative degradation amounts (BADA) based on the cumulative degradation amounts (CADA) (S340) and write the backup cumulative degradation amounts (BADA) to the internal life memory (210) of the afterimage compensation block (200) (S350). In one embodiment, the cumulative life calculator (230) can generate backup cumulative degradation amounts (BADA) for a plurality of second pixel blocks by merging the cumulative degradation amounts (CADA) for the plurality of first pixel blocks. Also, in one embodiment, the cumulative degradation amounts (CADA) are calculated in units of the first pixel block, and the backup cumulative degradation amounts (BADA) are calculated in units of the second pixel block, and the size of the second pixel block may be larger than the size of the first pixel block. Accordingly, the data size of the backup accumulated deterioration amounts (BADA) may be smaller than the data size of the accumulated deterioration amounts (CADA), and the internal lifetime memory (210) of the residual image compensation block (200) may have a size smaller than the volatile lifetime memory (170).

[0058] In the next frame, the data compensator (240) of the afterimage compensation block (200) reads the accumulated degradation amounts (RADA) from the volatile lifetime memory (170) (S360), and the lifetime comparator (250) of the afterimage compensation block (200) can compare the accumulated degradation amounts (RADA) read from the volatile lifetime memory (170) with the accumulated degradation amounts (CADA) calculated by accumulating the current degradation amounts (CDA) (S370). In one embodiment, the lifetime comparator (250) calculates a first checksum of accumulated degradation amounts (RADA) read from the volatile lifetime memory (170), calculates a second checksum of accumulated degradation amounts (CADA) calculated by accumulating current degradation amounts (CDA), and compares the first checksum with the second checksum to determine whether the accumulated degradation amounts (RADA) read from the volatile lifetime memory (170) are the same as the accumulated degradation amounts (CADA) calculated by accumulating current degradation amounts (CDA).

[0059] The data compensator (240) can compensate for the input image data (IDAT) in the next frame by selectively using the accumulated degradation amounts (RADA) read from the volatile lifetime memory (170) or the backup accumulated degradation amounts (BADA) stored in the internal lifetime memory (210) according to the result of the comparison (S370, S380, S390). For example, if the accumulated degradation amounts (RADA) read from the volatile lifetime memory (170) are the same as the accumulated degradation amounts (CADA) calculated by accumulating the current degradation amounts (CDA) (S370: YES), the data compensator (240) can compensate for the input image data (IDAT) in the next frame by using the accumulated degradation amounts (RADA) read from the volatile lifetime memory (170) (S380). Additionally, if the accumulated degradation amounts (RADA) read from the volatile lifetime memory (170) are different from the accumulated degradation amounts (CADA) calculated by accumulating the current degradation amounts (CDA) (S370: NO), the data compensator (240) can compensate the input image data (IDAT) in the next frame using the backup accumulated degradation amounts (BADA) stored in the internal lifetime memory (210) (S390).

[0060] As described above, in the afterimage compensation method of a display device (100) according to embodiments of the present invention, the afterimage compensation block (200) has an internal life memory (210), calculates accumulated degradation amounts (CADA) by accumulating current degradation amounts (CDA), reads accumulated degradation amounts (RADA) from a volatile life memory (170) located outside the afterimage compensation block (200), compares the calculated accumulated degradation amounts (CADA) with the read accumulated degradation amounts (RADA), and can compensate the input image data (IDAT) by selectively using the read accumulated degradation amounts (RADA) or the backup accumulated degradation amounts (BADA) stored in the internal life memory (210) according to the result of the comparison. Accordingly, even if a write or read operation for volatile and / or non-volatile lifetime memories (140, 170) located outside the residual image compensation block (200) is not performed normally due to ESD, memory access failure, hardware failure, etc., a residual image compensation operation can be performed normally using backup accumulated degradation amounts (BADA) of the internal lifetime memory (210).

[0061] FIG. 8 is a block diagram showing a display device according to embodiments of the present invention.

[0062] Referring to FIG. 8, a display device (400) according to embodiments of the present invention may include a display panel (410), a data driver (420), a scan driver (430), a non-volatile lifetime memory (440), and a controller (450). The controller (450) may include a volatile lifetime memory (470), a pre-scaling block (490), and a residual image compensation block (500). The residual image compensation block (500) may include an internal lifetime memory (510). The display device (400) of FIG. 8 may have a similar configuration and similar operation to the display device (100) of FIG. 1, except that the controller (450) further includes a pre-scaling block (490).

[0063] The pre-scaling block (490) receives accumulated degradation amounts from the afterimage compensation block (500), determines a pre-scaling coefficient based on the maximum accumulated degradation amount among the accumulated degradation amounts, applies the pre-scaling coefficient to the input image data (IDAT) to generate pre-scaled input image data (PSIDAT), and can provide the pre-scaled input image data (PSIDAT) to the afterimage compensation block (500). In one embodiment, the pre-scaling block (490) generates pre-scaled input image data (PSIDAT) that is reduced compared to the input image data (IDAT) based on the maximum accumulated degradation amount, and the afterimage compensation block (500) can generate output image data (ODAT) by increasing the pre-scaled input image data (PSIDAT) based on the accumulated degradation amounts. Accordingly, even if the input image data (IDAT) exhibits a maximum grayscale level (e.g., 255-grayscale level), the input image data (IDAT) is pre-scaled into pre-scaled input image data (PSIDAT) that is reduced compared to the input image data (IDAT), so that the afterimage compensation operation of increasing the pre-scaled input image data (PSIDAT) according to the accumulated degradation amounts can be performed normally.

[0064] FIG. 9 is a flowchart illustrating a method for compensating afterimages of a display device according to embodiments of the present invention.

[0065] Referring to FIGS. 8 and 9, in the current frame, the pre-scaling block (490) receives accumulated degradation amounts from the afterimage compensation block (500), determines a pre-scaling coefficient based on the maximum accumulated degradation amount among the accumulated degradation amounts, and can generate pre-scaled input image data (PSIDAT) by applying the pre-scaling coefficient to the input image data (IDAT) (S605). The afterimage compensation block (500) calculates current degradation amounts based on the pre-scaled input image data (PSIDAT) (S610), calculates accumulated degradation amounts by accumulating the current degradation amounts (S620), and can write the accumulated degradation amounts to a volatile lifetime memory (470) located outside the afterimage compensation block (500) (S630). Additionally, the residual image compensation block (500) can generate backup accumulated degradation amounts based on the accumulated degradation amounts (S640) and write the backup accumulated degradation amounts to the internal life memory (510) of the residual image compensation block (500) (S650).

[0066] In the next frame, the afterimage compensation block (500) can read the accumulated degradation amounts from the volatile lifetime memory (470) (S660). If the accumulated degradation amounts read from the volatile lifetime memory (470) are the same as the accumulated degradation amounts calculated by accumulating the current degradation amounts (S670: YES), the afterimage compensation block (500) can compensate the pre-scaled input image data (PSIDAT) in the next frame using the accumulated degradation amounts read from the volatile lifetime memory (470) (S680). Additionally, if the accumulated degradation amounts read from the volatile lifetime memory (470) are different from the accumulated degradation amounts calculated by accumulating the current degradation amounts (S670: NO), the afterimage compensation block (500) can compensate the pre-scaled input image data (PSIDAT) in the next frame using the backup accumulated degradation amounts stored in the internal lifetime memory (510) (S690).

[0067] FIG. 10 is a block diagram showing an electronic device including a display device according to embodiments of the present invention.

[0068] Referring to FIG. 10, the electronic device (1100) may include a processor (1110), a memory device (1120), a storage device (1130), an input / output device (1140), a power supply (1150), and a display device (1160). The electronic device (1100) may further include several ports capable of communicating with a video card, sound card, memory card, USB device, etc., or with other systems.

[0069] The processor (1110) can perform specific calculations or tasks. According to an embodiment, the processor (1110) may be a microprocessor, a central processing unit (CPU), etc. The processor (1110) may be connected to other components via an address bus, a control bus, a data bus, etc. According to an embodiment, the processor (1110) may also be connected to an expansion bus such as a Peripheral Component Interconnect (PCI) bus.

[0070] The memory device (1120) can store data necessary for the operation of the electronic device (1100). For example, the memory device (1120) may include non-volatile memory devices such as EPROM (Erasable Programmable Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), Flash Memory, PRAM (Phase Change Random Access Memory), RRAM (Resistance Random Access Memory), NFGM (Nano Floating Gate Memory), PoRAM (Polymer Random Access Memory), MRAM (Magnetic Random Access Memory), FRAM (Ferroelectric Random Access Memory), and / or volatile memory devices such as DRAM (Dynamic Random Access Memory), SRAM (Static Random Access Memory), and mobile DRAM.

[0071] The storage device (1130) may include a solid state drive (SSD), a hard disk drive (HDD), a CD-ROM, etc. The input / output device (1140) may include input means such as a keyboard, a keypad, a touchpad, a touchscreen, a mouse, etc., and output means such as a speaker, a printer, etc. The power supply (1150) may supply power required for the operation of the electronic device (1100). The display device (1160) may be connected to other components through the buses or other communication links.

[0072] In a display device (1160), the afterimage compensation block has an internal lifetime memory, calculates the accumulated degradation amounts by accumulating current degradation amounts, reads the accumulated degradation amounts from a volatile lifetime memory located outside the afterimage compensation block, compares the calculated accumulated degradation amounts with the read accumulated degradation amounts, and can compensate the input image data by selectively using the read accumulated degradation amounts or the backup accumulated degradation amounts stored in the internal lifetime memory according to the result of the comparison. Accordingly, even if a write operation or a read operation for a volatile / non-volatile lifetime memory located outside the afterimage compensation block is not performed normally due to electrostatic discharge (ESD), memory access failure, hardware failure, etc., the afterimage compensation operation can be performed normally using the backup accumulated degradation amounts of the internal lifetime memory.

[0073] According to an embodiment, the electronic device (1100) may be any electronic device including a display device (1160) such as a digital television, 3D TV, cellular phone, smartphone, tablet computer, VR device, personal computer (PC), home electronic device, laptop computer, personal digital assistant (PDA), portable multimedia player (PMP), digital camera, music player, portable game console, navigation, etc. Industrial applicability

[0074] The present invention can be applied to any organic light-emitting display device and electronic devices including the same. For example, the present invention can be applied to digital TVs, 3D TVs, mobile phones, smartphones, tablet computers, VR devices, PCs, home electronic devices, laptop computers, PDAs, PMPs, digital cameras, music players, portable game consoles, navigation systems, etc.

[0075] Although the present invention has been described above with reference to embodiments thereof, those skilled in the art will understand that various modifications and changes can be made to the invention without departing from the spirit and scope of the invention as described in the following claims. Explanation of the symbols

[0076] 100, 400: Display device 110, 410: Display panel 120, 420: Data driver 130, 430: Gate Driver 140, 440: Non-volatile lifetime memory 150, 450: Controller 170, 470: Volatile Lifetime Memory 200, 500: Afterimage compensation block 210, 510: Internal lifespan memory 220: Current Life Calculator 230: Cumulative Life Calculator 240: Data Compensator 250: Life Comparator 260: Weighting Determiner 490: Pre-scaling block

Claims

Claim 1 delete Claim 2 A display panel including a plurality of pixels; a data driver providing data signals to the plurality of pixels; a scan driver providing scan signals to the plurality of pixels;and controls the data driver and the scan driver, and includes a volatile lifetime memory that stores accumulated degradation amounts for the plurality of pixels, and an internal lifetime memory that stores backup accumulated degradation amounts generated based on the accumulated degradation amounts, and includes a controller that compensates input image data by selectively using the accumulated degradation amounts of the volatile lifetime memory or the backup accumulated degradation amounts of the internal lifetime memory, wherein the controller further includes an afterimage compensation block that compensates the input image data, wherein the volatile lifetime memory is located outside the afterimage compensation block, and the internal lifetime memory is located inside the afterimage compensation block, and the afterimage compensation block calculates current degradation amounts based on the input image data in the current frame, calculates accumulated degradation amounts by accumulating the current degradation amounts, writes the accumulated degradation amounts to the volatile lifetime memory, generates backup accumulated degradation amounts based on the accumulated degradation amounts, writes the backup accumulated degradation amounts to the internal lifetime memory, and in the next frame, reads the accumulated degradation amounts from the volatile lifetime memory, and A display device characterized by comparing the accumulated degradation amounts read from the volatile lifetime memory with the accumulated degradation amounts calculated in the current frame, and if the accumulated degradation amounts read from the volatile lifetime memory are the same as the accumulated degradation amounts calculated in the current frame, compensating the input image data in the next frame using the accumulated degradation amounts read from the volatile lifetime memory, and if the accumulated degradation amounts read from the volatile lifetime memory are different from the accumulated degradation amounts calculated in the current frame, compensating the input image data in the next frame using the backup accumulated degradation amounts stored in the internal lifetime memory. Claim 3 A display device according to claim 2, wherein the afterimage compensation block calculates a first checksum of the accumulated degradation amounts read from the volatile lifetime memory, calculates a second checksum of the accumulated degradation amounts calculated by accumulating the current degradation amounts, and compares the first checksum with the second checksum to determine whether the accumulated degradation amounts read from the volatile lifetime memory are the same as the accumulated degradation amounts calculated by accumulating the current degradation amounts. Claim 4 delete Claim 5 In claim 2, the afterimage compensation block comprises: the internal lifespan memory; a current lifespan calculator that divides the input image data in the current frame into a plurality of block image data for a plurality of first pixel blocks and calculates the current degradation amounts for the plurality of first pixel blocks based on the plurality of block image data; an accumulation lifespan calculator that calculates the accumulated degradation amounts for the plurality of first pixel blocks by accumulating the current degradation amounts for the plurality of first pixel blocks, writes the accumulated degradation amounts for the plurality of first pixel blocks to the volatile lifespan memory, generates the backup accumulated degradation amounts for the plurality of second pixel blocks by merging the accumulated degradation amounts for the plurality of first pixel blocks, and writes the backup accumulated degradation amounts for the plurality of second pixel blocks to the internal lifespan memory; and a data compensator that reads the accumulated degradation amounts for the plurality of first pixel blocks from the volatile lifespan memory.A display device comprising a life comparator that compares the accumulated degradation amounts read by the data comparator with the accumulated degradation amounts calculated by the accumulated life calculator, generates a fail flag signal having a first level when the accumulated degradation amounts read by the data comparator are the same as the accumulated degradation amounts calculated by the accumulated life calculator, and generates a fail flag signal having a second level when the accumulated degradation amounts read by the data comparator are different from the accumulated degradation amounts calculated by the accumulated life calculator; wherein the data comparator compensates the input image data using the accumulated degradation amounts for the plurality of first pixel blocks in response to the fail flag signal having the first level, reads the backup accumulated degradation amounts for the plurality of second pixel blocks from the internal life memory in response to the fail flag signal having the second level, and compensates the input image data using the backup accumulated degradation amounts for the plurality of second pixel blocks. Claim 6 A display device according to claim 5, characterized in that the size of each of the plurality of second pixel blocks is larger than the size of each of the plurality of first pixel blocks. Claim 7 A display device according to claim 5, wherein the life comparator calculates a first checksum of the accumulated deterioration amounts read by the data compensator, calculates a second checksum of the accumulated deterioration amounts calculated by the accumulated life calculator, and generates a fail flag signal by comparing the first checksum and the second checksum. Claim 8 A display device according to claim 5, wherein the afterimage compensation block further comprises a weighting determiner that determines block degradation weights for the plurality of first pixel blocks based on at least one of the driving frequency of the display panel, the temperature of the display panel, and the locations of the plurality of first pixel blocks. Claim 9 A display device according to claim 8, wherein the current life calculator calculates the current degradation amounts for the plurality of first pixel blocks by applying the block degradation weights to the plurality of block image data. Claim 10 A display device according to claim 2, wherein the controller further comprises a pre-scaling block that receives the accumulated degradation amounts from the afterimage compensation block, determines a pre-scaling coefficient based on the maximum accumulated degradation amount among the accumulated degradation amounts, generates pre-scaled input image data by applying the pre-scaling coefficient to the input image data, and provides the pre-scaled input image data to the afterimage compensation block. Claim 11 A display device according to claim 2, further comprising a non-volatile lifetime memory for storing the accumulated degradation amounts while the display device is powered off. Claim 12 A display device according to claim 11, wherein the controller periodically writes the accumulated degradation amounts stored in the volatile lifetime memory to the non-volatile lifetime memory. Claim 13 A method for compensating afterimages of a display device, comprising: a step of calculating current degradation amounts based on input image data in a current frame; a step of calculating accumulated degradation amounts by accumulating the current degradation amounts; a step of writing the accumulated degradation amounts to a volatile lifetime memory located outside the afterimage compensation block; a step of generating backup accumulated degradation amounts based on the accumulated degradation amounts; a step of writing the backup accumulated degradation amounts to an internal lifetime memory of the afterimage compensation block; a step of reading the accumulated degradation amounts from the volatile lifetime memory in the next frame; a step of comparing the accumulated degradation amounts read from the volatile lifetime memory with the accumulated degradation amounts calculated by accumulating the current degradation amounts; and a step of compensating the input image data in the next frame by selectively using the accumulated degradation amounts read from the volatile lifetime memory or the backup accumulated degradation amounts stored in the internal lifetime memory according to the result of the comparison. Claim 14 A method for compensating afterimages according to claim 13, wherein the step of compensating the input image data comprises: a step of compensating the input image data in the next frame using the accumulated degradation amounts read from the volatile lifetime memory when the accumulated degradation amounts read from the volatile lifetime memory are identical to the accumulated degradation amounts calculated by accumulating the current degradation amounts; and a step of compensating the input image data in the next frame using the backup accumulated degradation amounts stored in the internal lifetime memory when the accumulated degradation amounts read from the volatile lifetime memory are different from the accumulated degradation amounts calculated by accumulating the current degradation amounts. Claim 15 A residual image compensation method according to claim 13, wherein the step of comparing the accumulated degradation amounts read from the volatile lifetime memory with the accumulated degradation amounts calculated by accumulating the current degradation amounts comprises: a step of calculating a first checksum of the accumulated degradation amounts read from the volatile lifetime memory; a step of calculating a second checksum of the accumulated degradation amounts calculated by accumulating the current degradation amounts; and a step of determining whether the accumulated degradation amounts read from the volatile lifetime memory are the same as the accumulated degradation amounts calculated by accumulating the current degradation amounts by comparing the first checksum and the second checksum. Claim 16 A residual image compensation method according to claim 13, wherein the accumulated degradation amounts are calculated in units of a first pixel block, the backup accumulated degradation amounts are calculated in units of a second pixel block, and the size of the second pixel block is larger than the size of the first pixel block. Claim 17 A residual image compensation method according to claim 13, wherein the step of calculating the current degradation amounts comprises: a step of dividing the input image data in the current frame into a plurality of block image data for a plurality of first pixel blocks; a step of determining block degradation weights for the plurality of first pixel blocks based on at least one of the driving frequency of the display panel, the temperature of the display panel, and the positions of the plurality of first pixel blocks; and a step of calculating the current degradation amounts for the plurality of first pixel blocks by applying the block degradation weights to the plurality of block image data. Claim 18 In claim 17, the step of calculating the backup accumulated degradation amounts comprises merging the accumulated degradation amounts for the plurality of first pixel blocks to generate the backup accumulated degradation amounts for the plurality of second pixel blocks, thereby providing a residual image compensation method. Claim 19 A residual image compensation method according to claim 13, further comprising the step of periodically writing the accumulated degradation amounts stored in the volatile lifetime memory to the non-volatile lifetime memory. Claim 20 A residual image compensation method according to claim 13, further comprising: a step of determining a pre-scaling coefficient based on the maximum accumulated degradation amount among the accumulated degradation amounts; and a step of applying the pre-scaling coefficient to the input image data.

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