Display device and method for driving the same

Abstract

Disclosed are a display device and a method for driving the same. The display device includes: a memory configured to store an overdrive lookup table and previous frame block data generated by performing block averaging on the previous frame data; an overdriver configured to obtain current frame data from input image data and generate overdrive frame data for the current frame data by comparing the previous frame block data with the current frame data with reference to the overdrive lookup table; a data driver configured to generate an overdrive data signal based on the overdrive frame data; and a plurality of pixels configured to display an image based on the overdrive data signal, wherein the overdriver is configured to perform overdrive based on the size of the blocks divided for block averaging.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2020-0012707, filed on February 3, 2020, which is hereby incorporated by reference herein in its entirety. Technical Field

[0003] Aspects of some example embodiments of the present disclosure relate to a display device and a method of driving the display device. Background Art

[0004] As information technology develops, the importance of display devices that provide a connection medium between users and information is becoming increasingly important. Therefore, the use of display devices such as liquid crystal display devices, organic light emitting display devices, and plasma display devices has increased.

[0005] Each pixel of the display device may emit light at a brightness corresponding to a data voltage supplied through a corresponding data line. The display device may display an image frame having emission combinations of pixels.

[0006] On the other hand, when the response speed of the display device is slow, when rapidly changing or moving content is displayed, an afterimage in which an immediately previous screen and a new screen overlap each other may occur or a motion blur phenomenon may occur.

[0007] For example, the time required to switch between the darkest color and the lightest color or the time required to switch between a specific mixed color and an intermediate color may be slowed down, thereby reducing the display quality of the image perceived by the user.

[0008] The above information disclosed in this Background section is only for enhancement of understanding of the background and therefore, the information discussed in this Background section does not necessarily constitute prior art. Summary of the Invention

[0009] Aspects of some example embodiments of the present disclosure include a display device and a method of driving the display device, which perform block averaging (BA) on previous frame data and store it, limit the range to which overdriving is applied, and apply overdriving.

[0010] However, exemplary embodiments of the present disclosure are not limited to the above-described characteristics, and the embodiments may be variously extended within a range without departing from the spirit and scope of the present disclosure.

[0011] Aspects according to some example embodiments of the present disclosure include a display device.

[0012] According to some example embodiments, a display device may include: a memory configured to store an overdrive lookup table and previous frame block data generated by block averaging the previous frame data; an overdrive driver configured to acquire current frame data from input image data and generate overdrive frame data for the current frame data by comparing the previous frame block data and the current frame data with reference to the overdrive lookup table; a data driver configured to generate an overdrive data signal based on the overdrive frame data; and a plurality of pixels that display an image based on the overdrive data signal.

[0013] According to some example embodiments, the overdriver may perform overdriving based on the size of a block divided for block averaging.

[0014] According to some example embodiments, the previous frame block data may be data dividing the previous frame data into a plurality of blocks having a predetermined size and indicating an average value of a plurality of grayscale values included in each divided block as a grayscale value for each divided block.

[0015] According to some example embodiments, the overdriver may perform overdriving according to a result obtained by comparing a value obtained by dividing a grayscale value of current frame data by a block size with a grayscale value of previous frame block data.

[0016] According to some example embodiments, the over-driver may perform over-driving when a grayscale value of current frame data is greater than a grayscale value of previous frame block data.

[0017] According to some example embodiments, at least one of a first bit number as a bit number of previous frame data defined in the overdrive lookup table and a second bit number as a bit number of current frame data defined in the overdrive lookup table may be smaller than a bit number of input image data.

[0018] According to some example embodiments, the overdriver may perform bit conversion on the number of bits of input image data into a first number or a second number.

[0019] According to some example embodiments, the overdrive driver may divide a plurality of grayscale values of current frame data included in the input image data into a plurality of intervals having unequal intervals, and perform bit conversion by respectively mapping the plurality of intervals to a plurality of grayscale values of the current frame data defined in the overdrive lookup table.

[0020] According to some example embodiments, as the grayscale value of the input image data is smaller, intervals in at least some of the plurality of intervals may be set to be narrower.

[0021] According to some example embodiments, the first digit and the second digit may be different.

[0022] According to some example embodiments, the overdriver may perform overdriving based on the size of the block and a difference between the first digit and the second digit.

[0023] According to some example embodiments, when the second digit is greater than the first digit, the overdriver may perform overdriving based on a value obtained by multiplying the size of the block by the difference value.

[0024] According to some example embodiments, when the second digit is smaller than the first digit, the overdriver may perform overdriving based on a value obtained by dividing the size of the block by the difference value.

[0025] Aspects of some example embodiments of the present disclosure include a method of driving a display device.

[0026] According to some example embodiments, a method of driving a display device includes: acquiring current frame data from input image data; acquiring previous frame block data generated by block averaging the previous frame data and an overdrive lookup table from a memory; generating overdrive frame data for the current frame data by comparing the current frame data with the previous frame block data with reference to the overdrive lookup table; generating an overdrive data signal based on the overdrive frame data; and supplying the overdrive data signal to a plurality of pixels.

[0027] According to some example embodiments, generating the overdrive frame data may include generating the overdrive frame data based on sizes of blocks divided for block averaging.

[0028] According to some example embodiments, the previous frame block data may be data dividing the previous frame data into a plurality of blocks having a preset size and indicating an average value of a plurality of grayscale values included in each divided block as a grayscale value for each divided block.

[0029] According to some example embodiments, generating the overdrive frame data may include generating the overdrive frame data according to a result obtained by comparing a value obtained by dividing a grayscale value of current frame data by a block size with a grayscale value of previous frame block data.

[0030] According to some example embodiments, at least one of a first bit number as a bit number of previous frame data defined in the overdrive lookup table and a second bit number as a bit number of current frame data defined in the overdrive lookup table may be smaller than a bit number of input image data.

[0031] According to some example embodiments, generating the overdrive frame data may include performing bit conversion on a number of bits of the input image data into a first number of bits or a second number of bits.

[0032] According to some example embodiments, performing bit conversion may include dividing a plurality of grayscale values of current frame data included in the input image data into a plurality of intervals having unequal intervals, and performing bit conversion by respectively mapping the plurality of intervals to a plurality of grayscale values of the current frame data defined in an overdrive lookup table.

[0033] According to some example embodiments, the first digit and the second digit may be different.

[0034] According to some example embodiments, generating the overdrive frame data may include generating the overdrive frame data based on a size of the block and a difference between a first number and a second number.

[0035] According to some example embodiments, a display device and a method of driving a display device according to the present disclosure performs block averaging (BA) on the previous frame data and stores the BA, and limits the range of overdriving according to a standard (e.g., a predetermined standard). Therefore, a lookup table (LUT) can also be configured in a relatively simplified form, thereby minimizing memory capacity.

[0036] For example, by limiting the range so that overdrive does not have to be applied to a still image, image variation due to overdrive of the still image can be prevented.

[0037] In addition, since the lookup table (LUT) is generated by bit conversion for grayscale values, the size of the lookup table (LUT) can be reduced. In addition, since the bit conversion is performed by dividing a plurality of grayscale values into a plurality of intervals with unequal intervals, overdrive can be finely applied to grayscale values that are easily recognized by the user, and overdrive can be simplified and applied to grayscale values that are not easily recognized by the user. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The above and other features and characteristics according to the embodiments of the present disclosure will become more apparent by further describing the embodiments thereof in detail with reference to the accompanying drawings, in which:

[0039] Figure 1 is a block diagram illustrating a display device according to some example embodiments of the present disclosure;

[0040] Figure 2 is a conceptual diagram for describing a schematic operation of an overdriver according to some example embodiments of the present disclosure;

[0041] Figure 3 is a conceptual diagram for describing a method of performing block averaging according to some example embodiments of the present disclosure;

[0042] Figure 4 Is used to describe when using Figure 3 A conceptual diagram of the range of overdriving when overdriving is performed by block averaging;

[0043] Figure 5 is a table for describing a bit conversion process according to some example embodiments of the present disclosure;

[0044] Figure 6 is a conceptual diagram for describing a method for performing overdriving when the number of bits of previous frame block data defined in an overdriving lookup table is smaller than the number of bits of current frame data according to some embodiments of the present disclosure;

[0045] Figure 7 is a conceptual diagram for describing a method of performing overdriving when the number of bits of previous frame block data defined in an overdriving lookup table is greater than the number of bits of current frame data according to some example embodiments of the present disclosure; and

[0046] Figure 8 is a flowchart illustrating a method of driving a display device according to some example embodiments of the present disclosure. DETAILED DESCRIPTION

[0047] Hereinafter, various aspects of some example embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings so that those skilled in the art can easily perform the present disclosure. Embodiments according to the present disclosure can be implemented in various different forms and are not limited to the example embodiments described herein.

[0048] In order to clearly describe the present disclosure, parts not related to the description are omitted, and the same or similar components are represented by the same reference numerals throughout the specification. Therefore, the above reference numerals may be used in other figures.

[0049] In addition, for the convenience of description, the size and thickness of each component shown in the drawings are arbitrarily shown, and therefore, the present disclosure is not necessarily limited to those shown in the drawings. In the drawings, the thickness may be exaggerated to clearly show various layers and regions.

[0050] Figure 1 is a block diagram illustrating a display device according to some example embodiments of the present disclosure.

[0051] Reference Figure 1 , the display device DD may include an overdriver 100 , a timing controller 200 , a scan driver 300 , an emission driver 400 , a data driver 500 , a display panel 600 , and a power manager 700 .

[0052] The overdriver 100 may receive input image data IPdata provided from the timing controller 200 and may perform overdriving on the received input image data IPdata to output overdriving data ODdata.

[0053] Overdriving refers to a technology that improves the response speed of the display device DD by instantaneously (for example, one frame period) applying a voltage slightly higher (or slightly lower depending on the situation) than the voltage level required by the pixel PX[i, j] and then reducing the voltage to the existing target voltage, and may include dynamic capacitance compensation (DCC).

[0054] As an example of overdriving, by applying a driving voltage higher than that of the pixel PX[i,j] to the pixel PX[i,j] according to the input image data IPdata, an overshoot effect can be obtained, and thus, the response speed can be improved.

[0055] According to some example embodiments, the overdriver 100 may generate the overdriving data ODdata by changing a grayscale value of the input image data IPdata.

[0056] The timing controller 200 may generate a scan control signal SCS, an emission control signal ECS, and a data control signal DCS in response to a synchronization signal supplied from the outside. The scan control signal SCS may be supplied to the scan driver 300, the emission control signal ECS may be supplied to the emission driver 400, and the data control signal DCS may be supplied to the data driver 500.

[0057] In addition, the timing controller 200 may supply the overdrive data ODdata supplied from the overdriver 100 to the data driver 500 as the image data RGB, or may rearrange the overdrive data ODdata and supply the rearranged overdrive data to the data driver 500 .

[0058] The scan control signal SCS may include a scan start signal and a clock signal. The scan start signal may control the first timing of the scan signal. The clock signal may be used to shift the scan start signal.

[0059] The emission control signal ECS may include an emission start signal and a clock signal. The emission start signal may control the first timing of the emission signal. The clock signal may be used to shift the emission start signal.

[0060] The data control signal DCS may include a source start pulse and a clock signal. The source start pulse may control the start time of data sampling. The clock signal may be used to control the sampling operation.

[0061] The scan driver 300 may receive a scan control signal SCS from the timing controller 200 and sequentially supply scan signals to the scan lines SL[1], SL[2], ..., and SL[p] based on the scan control signal SCS. When the scan signals are sequentially supplied, pixels PX[i, j] may be selected in units of horizontal lines (or pixel rows), and data signals (or data voltages) may be supplied to the selected pixels PX[i, j].

[0062] The scan driver 300 may include a scan stage configured in the form of a shift register and may generate a scan signal by sequentially transmitting a scan start signal in the form of a pulse of an on level to the next scan stage under the control of a clock signal.

[0063] The emission driver 400 may receive an emission control signal ECS from the timing controller 200 and sequentially supply emission signals to the emission control lines EL[1], EL[2], ..., and EL[p] based on the emission control signal ECS. The emission signal may be used to control the emission time of the pixel PX[i, j]. To this end, the emission signal may be set to a width wider than the scan signal.

[0064] The data driver 500 may receive the data control signal DCS and the image data RGB from the timing controller 200. The image data RGB may be the same as the overdriving data ODdata of the overdriver 100 or data obtained by converting the overdriving data ODdata.

[0065] The data driver 500 may generate a data signal based on the overdrive data ODdata and supply the data signal (or data voltage) to the data lines DL[1], DL[2], ..., and DL[q] in response to the data control signal DCS. The data signals supplied to the data lines DL[1], DL[2], ..., and DL[q] may be supplied to the pixels PX[i, j] selected by the scan signal. To this end, the data driver 500 may supply the data signals to the data lines DL[1], DL[2], ..., and DL[q] in synchronization with the scan signal.

[0066] The display panel 600 may include a plurality of pixels PX[i, j]. The plurality of pixels PX[i, j] may be configured by p rows (p is a natural number) and q columns (q is a natural number), and the pixels PX[i, j] in the same row may be connected to the same scan line SL[i] and the same emission control line EL[i]. In addition, the pixels PX[i, j] in the same column may be connected to the same data line DL[j].

[0067] For example, the pixel PX[i,j] located in the i-th row and j-th column can be connected to the scan line SL[i] corresponding to the i-th row (or horizontal line), the emission control line EL[i] corresponding to the i-th row and the data line DL[j] corresponding to the j-th column.

[0068] The power manager 700 may supply a voltage of a first power source VDD, a voltage of a second power source VSS, and a voltage of an initialization power source Vint to the display panel 600. However, this is merely an example, and at least one of the first power source VDD, the second power source VSS, and / or the initialization power source Vint may be supplied to the display panel 600 from the timing controller 200 or the data driver 500.

[0069] The first power supply VDD and the second power supply VSS may generate a voltage for driving each pixel PX[i, j] of the display panel 600. According to some example embodiments, the voltage of the second power supply VSS may be lower than the voltage of the first power supply VDD. For example, the voltage of the first power supply VDD may be a positive voltage, and the voltage of the second power supply VSS may be a negative voltage. The initialization power supply Vint may be a power supply for initializing each pixel PX[i, j] included in the display panel 600.

[0070] On the other hand, Figure 1 In the embodiment, the overdriver 100 receives the input image data IPdata from the timing controller 200, but is not limited thereto. For example, the overdriver 100 may be entirely implemented in the timing controller 200. In this case, the timing controller 200 may receive the input image data IPdata from the outside and may generate the overdrive data ODdata using the supplied input image data IPdata.

[0071] Figure 2 is a conceptual diagram for describing a schematic operation of an overdriver according to some example embodiments of the present disclosure.

[0072] The input image data IPdata may include data formed by a plurality of frame units. For example, the input image data IPdata may include current frame data DCF, previous frame data DPF, and next frame data DNF. Here, the previous frame data DPF may be data that is temporally before the current frame data DCF and temporally adjacent to the current frame data DCF. The next frame data DNF may be data that is temporally later than the current frame data DCF and temporally adjacent to the current frame data DCF. The current frame data DCF, the previous frame data DPF, or the next frame data DNF may include grayscale values expressed in each pixel of the display panel 600 in units of frames (more specifically, grayscale values quantized in units of bits).

[0073] In addition, the over-driving data ODdata may include at least one over-driving frame data DOF corresponding to each frame data of the input image data IPdata.

[0074] The overdriver 100 may include a microprocessing unit (MPU) 110 and a memory 120. The microprocessing unit 110 generates overdrive frame data DOF by comparing the previous frame data DPF with the current frame data DCF with reference to an overdrive lookup table (LUT). The memory 120 stores the previous frame data and the overdrive lookup table LUT. Hereinafter, for convenience of description, the operation of the microprocessing unit 110 may be referred to as the operation of the overdriver 100.

[0075] The memory 120 may store the previous frame data DPF. However, the memory 120 may also store the previous frame block data B_DPF generated by performing block averaging on the previous frame data DPF to reduce costs by reducing the consumed capacity of the memory 120.

[0076] Here, the memory 120 may be configured by at least one of a read only memory (ROM) and a random access memory (RAM).

[0077] The overdriver 100 may compare the previous frame data DPF with the current frame data DCF with reference to the overdrive lookup table LUT to generate overdrive frame data DOF for the current frame data DCF. More specifically, the overdriver 100 may generate overdrive data DOF by comparing the previous frame block data B_DPF with the current frame data DCF.

[0078] The overdriver 100 may store the current frame block data B_DCF generated by performing block averaging (BA) on the current frame data DCF in the memory 120. Here, the stored current frame block data B_DCF may be used as previous frame block data when generating overdrive frame data for subsequent frame data DNF of the current frame data DCF.

[0079] Figure 3 is a conceptual diagram for describing a method of performing block averaging according to some example embodiments of the present disclosure.

[0080] According to some example embodiments of the present disclosure, in order to minimize the capacity of the memory 120 , instead of storing the previous frame data DPF in the memory 120 , the previous frame block data B_DPF generated by performing block averaging on the previous frame data DPF may be stored in the memory 120 .

[0081] Here, the previous frame block data B_DPF may be data that divides the previous frame data into a plurality of blocks having a preset size of n×n (n is a natural number equal to or greater than 2) and configured by an average value of a plurality of grayscale values included in each block.

[0082] For example, refer to Figure 3, the previous frame data DPF may be divided into a plurality of blocks having a size of 2×2. At this time, four grayscale values (more specifically, grayscale values represented by four bits) included in the first block BLK1 of the previous frame data DPF may be 9, 0, 0, 0.

[0083] At this time, the overdriver 100 can calculate an average value relative to multiple grayscale values included in the first block BLK1 (at this time, the decimal point can be rounded up relative to the calculated average value), and can generate the previous frame block data B_DPF indicating the calculated average value 3 as the grayscale value for the first block BLK1.

[0084] Therefore, when the average value 3 is stored as the previous frame block data B_DPF in the memory 120, instead of storing grayscale values corresponding to four pixels included in the first block BLK1, the capacity occupied by the previous frame data DPF in the memory 120 can be reduced to 1 / 4.

[0085] In the future, when referring to the overdrive lookup table LUT, the grayscale values G1, G2, G3 and G4 belonging to the position corresponding to the first block BLK1 in the current frame data DCF and the grayscale values for the first block BLK1 in the previous frame block data B_DPF (for example, the average value 3 as shown in the figure) can correspond to each other and can be compared with each other.

[0086] because Figure 3 It is shown that under the assumption of a still image, the previous frame data DPF and the current frame data DCF are identical to each other, so similar to the grayscale values belonging to the first block BLK1 in the previous frame data DPF, the grayscale values G1, G2, G3 and G4 belonging to the position corresponding to the first block BLK1 in the current frame data DCF are 9, 0, 0, 0.

[0087] Figure 4 Is used to describe when using Figure 3 A conceptual diagram of the range of overdriving when overdriving is performed using block averaging.

[0088] The over-driving lookup table LUT may be a table in which grayscale values applied to over-driving are pre-defined according to a corresponding relationship between grayscale values of previous frame data DPF and grayscale values of current frame data DCF.

[0089] On the other hand, when the assumption is made that Figure 3 When the block average is performed, the overdrive lookup table LUT can be understood as a table which defines the grayscale value of the previous frame block data B_DPF instead of the corresponding relationship between the grayscale value of the previous frame data DPF and the grayscale value of the current frame data DCF.

[0090] For example, when the grayscale value of the previous frame block data B_DPF is represented by 4 bits and the grayscale value of the current frame data DCF is represented by 4 bits, the overdrive lookup table LUT can limit the grayscale value used for overdriving relative to the correspondence between 0 to 15 that can become the grayscale value of the previous frame block data B_DPF and 0 to 15 that can become the grayscale value of the current frame data DCF.

[0091] Specifically, referring to the first lookup table LUT1, when the grayscale value of the previous frame block data B_DPF is 3 and the grayscale value of the current frame data DCF is 9, in order to improve the response speed according to the grayscale value increase of a larger width, the grayscale value of the current frame data DCF may be converted to 11 for application. As described above, when the current frame data DCF is converted with reference to the overdrive lookup table LUT, the overdrive frame data DOF may be generated.

[0092] For example, the overdriver 100 may perform overdriving when the grayscale value of the current frame data DCF is greater than the grayscale value of the previous frame block data B_DPF (overdriving coverage range 1).

[0093] On the other hand, when using block averaging, there is a problem of performing overdrive even when it is not necessary. For example, in the case of a still image, the previous frame data DPF and the current frame data DCF are the same. Therefore, since a still image does not change on the displayed screen, it is advantageous not to perform overdrive.

[0094] However, in the case where the previous frame block data B_DPF is stored in the memory 120 instead of the previous frame data DPF and is referred to when overdriving is performed, overdriving may be performed even in the case of a still image.

[0095] For example, in Figure 3 , the first gray value G1 of the current frame data DCF belonging to the position corresponding to the first block BLK1 corresponds to the gray value 3 for the first block BLK1 of the previous frame block data B_DPF.

[0096] Therefore, as in Figure 4 In the overdrive lookup table LUT shown on the left side of , since the grayscale value 3 of the previous frame block data B_DPF corresponds to the grayscale value 9 of the current frame data DCF, there is a problem of performing overdrive due to the overdrive coverage range 1 even in the case of a still image.

[0097] In order to prevent the problem caused by block averaging as described above, the overdriver 100 may perform overdriving based on the size of the block divided for block averaging.

[0098] For example, the overdriver 100 may perform overdriving based on a result obtained by comparing a value obtained by dividing a grayscale value of the current frame data DCF by the size of a block with a grayscale value of the previous frame block data B_DPF.

[0099] In more detail, when the size of the block is n×n and satisfies the following Equation 1 (overdriving coverage 2), the overdriver 100 may perform overdriving.

[0100] Equation 1

[0101]

[0102] Referring to Equation 1, "roundup" may refer to a function for rounding up decimal points equal to or less than 0, "VDCF" may refer to the grayscale value of the current frame data DCF, and "VBDPF" may refer to the grayscale value of the previous frame block data B_DPF. The round-up operation described above in Equation 1 is merely an example and is not necessarily limited thereto. For example, a round-down operation or a round-up operation may be applied instead of the round-up operation. The round-up operation described below should be interpreted as being similarly replaced by the round-down operation or the round-up operation.

[0103] The case where Equation 1 is satisfied (overdrive coverage 2) is the same as that of the second lookup table LUT2. As shown in the second lookup table LUT2, when the block size is Figure 3 When the value 3 obtained by rounding up the grayscale value 9 of the current frame data DCF divided by 4 is not greater than the grayscale value 3 of the previous frame block data B_DPF, the value 3 obtained by rounding up the value 9 of the current frame data DCF divided by 4 is not greater than the grayscale value 3 of the previous frame block data B_DPF. Figure 3 Overdriving is not performed in still images with grayscale values of

[0104] Figure 5 is a table for describing a bit conversion process according to some example embodiments of the present disclosure.

[0105] Figure 4 Lookup tables LUT1 and LUT2 are shown for a case where the grayscale value of the previous frame block data B_DPF is 4 bits and the grayscale value of the current frame data DCF is 4 bits.

[0106] However, the number of bits of the previous frame data DPF (hereinafter, may be referred to as a first number) and the number of bits of the current frame data DCF (hereinafter, may be referred to as a second number) defined in the overdriving lookup table LUT may be changed.

[0107] Specifically, in order to reduce the size of the previous frame data DPF or the previous frame block data B_DPF stored in the memory 120 (or reduce the size of the overdrive lookup table LUT), at least one of the first digit and the second digit may be smaller than the number of bits of the input image data IPdata.

[0108] For example, even if the input image data IPdata has 8 bits, the first bit as the number of bits of the previous frame data DPF can be 4 bits, which is smaller than 8 bits. In addition, even if the input image data IPdata has 8 bits, the second bit as the number of bits of the current frame data DPF can be 4 bits, which is smaller than 8 bits.

[0109] As described above, when the number of bits of the input image data IPdata and the number of bits (first digit and second digit) defined in the overdrive lookup table LUT are different from each other, it may be necessary to perform bit conversion on the number of bits of the input image data IPdata. That is, the overdriver 100 may perform bit conversion on the number of bits of the input image data IPdata to the first digit or the second digit before referring to the overdrive lookup table LUT. Specifically, for example, the overdriver 100 may bit-convert the number of bits of the current frame data DCF included in the input image data IPdata into the second digit. Alternatively, the overdriver 100 may bit-convert the number of bits of the current frame data DCF into the first digit, and may store the current frame block data B_DCF generated by performing block averaging on the bit-converted current frame data DCF in the memory 120 (at this time, the order between bit conversion and block averaging may be changed).

[0110] According to some example embodiments, a method of performing bit conversion is as follows. For example, the plurality of grayscale values of the input image data IPdata may be divided into a plurality of intervals having equal intervals, and each interval may correspond to a grayscale value according to a first digit or a second digit. In other words, the grayscale value of the input image data IPdata may be shifted to be converted to a first digit or a second digit.

[0111] According to some example embodiments, a method of performing bit conversion is as follows. For example, the plurality of grayscale values of the input image data IPdata may be divided into a plurality of intervals having unequal intervals, and each interval may correspond to a grayscale value according to the first digit or the second digit. In this case, as the grayscale value of the input image data IPdata decreases, the interval of each interval may be set to be narrower.

[0112] Reference Figure 5 , shows an example table for converting input image data IPdata having 8-bit grayscale values into 3-bit grayscale values defined in the overdrive lookup table LUT.

[0113] Reference Figure 5, 8-bit grayscale values 0 to 1 (interval interval 1) can be converted to 3-bit grayscale value 0. In addition, 8-bit grayscale values 2 to 3 (interval interval 1) can be converted to 3-bit grayscale value 1. In addition, 8-bit grayscale values 4 to 7 (interval interval 3) can be converted to 3-bit grayscale value 2. In addition, 8-bit grayscale values 8 to 15 (interval interval 7) can be converted to 3-bit grayscale value 3. In addition, 8-bit grayscale values 16 to 31 (interval interval 15) can be converted to 3-bit grayscale value 4. In addition, 8-bit grayscale values 32 to 63 (interval interval 31) can be converted to 3-bit grayscale value 5. In addition, 8-bit grayscale values 64 to 127 (interval interval 63) can be converted to 3-bit grayscale value 6. In addition, 8-bit grayscale values 128 to 255 (interval interval 127) can be converted to 3-bit grayscale value 7.

[0114] That is to say, if Figure 5 As shown in , as the grayscale value of the input image data IPdata decreases, the interval of each interval can be set to be narrower, and the grayscale value of the input image data IPdata can be set to be larger. Therefore, because bit conversion can be performed in fine intervals at low grayscales, overdrive can be operated more finely at low grayscales that are easily recognized by the user.

[0115] Figure 6 is a conceptual diagram for describing a method of performing overdriving when the number of bits of previous frame block data defined in an overdriving lookup table is smaller than the number of bits of current frame data according to some example embodiments of the present disclosure.

[0116] Reference Figure 6 , the number of bits (or first digit) of the previous frame block data B_DPF defined in the third lookup table LUT3 and the fourth lookup table LUT4 is 3 bits, and the number of bits (or second digit) of the current frame data DCF is 4 bits.

[0117] As described above, when the first digit and the second digit are different from each other, similar to the Figure 4 The overdriver 100 may perform overdriving when the grayscale value of the current frame data DCF is greater than the grayscale value of the previous frame block data B_DPF (overdriving coverage range 3). However, at this time, the magnitude of the absolute grayscale value may be considered based on the bit difference.

[0118] For example, it is shown in the case where it is assumed that a plurality of grayscale values of the input image data IPdata are divided into a plurality of intervals with equal intervals and bit conversion is performed by mapping the plurality of intervals to a plurality of grayscale values according to the first digit or the second digit, respectively. Figure 6In this case, the grayscale value of 0 of the 3-bit previous frame block data B_DPF corresponds to the grayscale value of 0 of the 4-bit current frame data DCF. Therefore, when the grayscale value of the 3-bit previous frame block data B_DPF is 0, overdriving can be performed when the grayscale value of the 4-bit current frame data DCF is greater than or equal to 1. In addition, the grayscale value of 1 of the 3-bit previous frame block data B_DPF corresponds to the grayscale value of 2 of the 4-bit current frame data DCF. Therefore, when the grayscale value of the 3-bit previous frame block data B_DPF is 1, overdriving can be performed when the grayscale value of the 4-bit current frame data DCF is greater than or equal to 3.

[0119] In addition, when the first and second digits are different from each other, the overdriver 100 may perform overdriving based on the size of the block divided for block averaging and the difference between the first and second digits. More specifically, when the number of bits of the current frame data DCF (the second digit) defined in the overdrive lookup table LUT is greater than the number of bits of the previous frame data DPF (the first digit), the overdriver 100 may perform overdriving based on a value obtained by multiplying the size of the block divided for block averaging by the difference.

[0120] For example, when the size of the block is n×n and the difference value is d, the overdriver 100 may perform overdriving when the following Equation 2 is satisfied (overdriving coverage 4).

[0121] Equation 2

[0122]

[0123] In Equation 2, the remaining values except the difference d are the same as those in Equation 1, and therefore, repeated descriptions are omitted. The case where Equation 2 is satisfied (overdrive coverage 4) is the same as that of the fourth lookup table LUT4. Referring to the fourth lookup table LUT4, when the block size is 2×2 and the difference is 1, overdrive can be performed according to Equation 2. Because the difference d is 1 and the variable n according to the block size is 2, when the grayscale value VDCF of the current frame data DCF is 0 to 8, the round-up operation value on the left side of Equation 2 is 1. Therefore, when the grayscale value VBDPF of the previous frame block data B_DPF is 1, overdrive can be performed when the grayscale value VDCF of the current frame data DCF is greater than or equal to 9.

[0124] Figure 7 is a conceptual diagram for describing a method of performing overdriving when the number of bits of previous frame block data defined in an overdriving lookup table is greater than the number of bits of current frame data according to some example embodiments of the present disclosure.

[0125] Reference Figure 7, it is limited that the number of bits (or the first digit) of the previous frame block data B_DPF in the fifth lookup table LUT5 and the sixth lookup table LUT6 is 4 bits, and the number of bits (or the second digit) of the current frame data DCF is 3 bits.

[0126] As described above, when the first digit is greater than the second digit, similar to the Figure 4 According to the first lookup table LUT1, the overdriver 100 may perform overdriving when the grayscale value of the current frame data DCF is greater than the grayscale value of the previous frame block data B_DPF (overdriving coverage range 5).

[0127] For example, it is shown in the case where it is assumed that a plurality of grayscale values of the input image data IPdata are divided into a plurality of intervals with equal intervals and bit conversion is performed by mapping the plurality of intervals to a plurality of grayscale values according to the first digit or the second digit, respectively. Figure 7 Specifically, the grayscale values 0 and 1 of the 4-bit previous frame block data B_DPF correspond to the grayscale value 0 of the 3-bit current frame data DCF. Therefore, when the grayscale values of the 4-bit previous frame block data B_DPF are 0 and 1, overdriving is performed when the grayscale value of the 3-bit current frame data DCF is greater than or equal to 1.

[0128] In addition, when the first digit is greater than the second digit (or when the second digit is smaller than the first digit), overdriving can be performed based on a value obtained by dividing the size of the block divided for block averaging by the difference between the first digit and the second digit.

[0129] For example, when the size of the block is n×n and the difference value is d, the overdriver 100 may perform overdriving when the following Equation 3 is satisfied (overdriving coverage 6).

[0130] Equation 3

[0131]

[0132] The value according to Equation 3 is the same as that of Equation 2, and therefore, repeated description is omitted. The case where Equation 3 is satisfied (overdrive coverage 6) is the same as that of the sixth lookup table LUT6. Referring to the sixth lookup table LUT6, when the block size is 2×2 and the difference value is 1, overdrive can be performed according to Equation 3.

[0133] on the other hand, Figure 4 、 Figure 6 and Figure 7The lookup tables LUT1, LUT2, LUT3, LUT4, LUT5, and LUT6 shown in the figure define all correspondences between the grayscale values of the previous frame block data B_DPF and the grayscale values of the current frame data DCF, but are not limited thereto. For example, in order to reduce the capacity occupied by the overdrive lookup table LUT in the memory 120, the overdrive lookup table LUT (overdrive coverage range 1 to overdrive coverage range 6) can be defined only when overdrive is performed. In this case, the overdriver 100 can determine not to perform overdrive when the correspondence is not defined in the overdrive lookup table LUT, and the grayscale value of the current frame data DCF can be used as the grayscale value of the overdrive frame data DOF.

[0134] In addition, the user can choose whether to perform overdriving according to Equations 1 to 3 (overdriving coverage 2, overdriving coverage 4 and overdriving coverage 6), or to perform overdriving only when the grayscale value of the current frame data DCF is greater than the grayscale value of the previous frame block data B_DPF (overdriving coverage 1, overdriving coverage 3 and overdriving coverage 5).

[0135] When overdriving is performed when the grayscale value of the current frame data DCF is greater than the grayscale value of the previous frame block data B_DPF (overdriving coverage 1, overdriving coverage 3, and overdriving coverage 5), overdriving may be performed even in a still image, and therefore, there may be an effect that the edge portion of the image becomes clearly visible.

[0136] However, when the user does not like the change of the still image, the user may choose to perform overdriving according to Equations 1 to 3 (overdrive coverage 2, overdrive coverage 4, and overdrive coverage 6). Therefore, the display device DD may include a user interface for receiving the user's selection input.

[0137] Figure 8 is a flowchart illustrating a method of driving a display device according to some example embodiments of the present disclosure.

[0138] Reference Figure 8 , a method for driving a display device may include: acquiring current frame data from input image data (S100); acquiring previous frame block data generated by block averaging the previous frame data and an overdrive lookup table from a memory (S110); generating overdrive frame data for the current frame data by comparing the current frame data with the previous frame block data with reference to the overdrive lookup table (S120); generating an overdrive data signal based on the overdrive frame data (S130); and supplying the overdrive data signal to a plurality of pixels (S140).

[0139] Generating the overdrive frame data ( S120 ) may include generating the overdrive frame data based on the size of the block divided for block averaging.

[0140] The previous frame block data may be data that divides the previous frame data into a plurality of blocks having a preset size and indicates an average value of a plurality of grayscale values included in each divided block as a grayscale value for each divided block.

[0141] Generating the overdrive frame data ( S120 ) may include generating the overdrive frame data according to a result obtained by comparing a value obtained by dividing a grayscale value of current frame data by a block size with a grayscale value of previous frame block data.

[0142] At least one of a first bit number as a bit number of previous frame data defined in the overdrive lookup table and a second bit number as a bit number of current frame data defined in the overdrive lookup table may be smaller than a bit number of input image data.

[0143] Generating the overdrive frame data ( S120 ) may include performing bit conversion on the number of bits of the input image data into a first number of bits or a second number of bits.

[0144] Performing bit conversion may include dividing multiple grayscale values of current frame data included in the input image data into multiple intervals with unequal intervals, and performing bit conversion by respectively mapping the multiple intervals to multiple grayscale values of the current frame data defined in the overdrive lookup table.

[0145] The first and second digits can be different.

[0146] Generating the overdrive frame data ( S120 ) may include generating the overdrive frame data based on the size of the block and a difference between the first and second digits.

[0147] In addition, the method of driving the display device may include referring to Figures 1 to 7 The operation of the display device DD is described, and in order to avoid repeated description, a detailed description thereof is omitted.

[0148] The referenced drawings and the detailed description of the present disclosure are merely examples of the present disclosure and are used only to describe the present disclosure. They are not intended to limit the meaning and scope of the present disclosure described in the claims. Therefore, it will be understood by those skilled in the art that various modifications and equivalent embodiments are possible based on these drawings and detailed descriptions. Therefore, the true scope of the present disclosure should be determined by the technical spirit of the appended claims.

Claims

1. A display device comprising: a memory configured to store the overdrive lookup table and block data of a previous frame generated by performing block averaging on data of a previous frame; an overdrive driver configured to acquire current frame data from input image data, and generate overdrive frame data for the current frame data by comparing the previous frame block data with the current frame data with reference to the overdrive lookup table; a data driver configured to generate an overdrive data signal based on the overdrive frame data; as well as a plurality of pixels configured to display an image based on the overdrive data signal, wherein the overdriver is configured to perform overdriving based on the size of the block divided for the block averaging, and The over-driver is configured to perform the over-driving according to a result obtained by comparing a value obtained by dividing a grayscale value of the current frame data by a size of the block with a grayscale value of the previous frame block data.

2. The display device according to claim 1, wherein The previous frame block data is data that divides the previous frame data into a plurality of blocks having a predetermined size and indicates an average value of a plurality of grayscale values included in each divided block as a grayscale value for each divided block.

3. The display device according to claim 2, wherein: The over-driver is configured to perform the over-driving when a grayscale value of the current frame data is greater than a grayscale value of the previous frame block data.

4. The display device according to claim 1, wherein At least one of a first bit number as the number of bits of the previous frame data defined in the overdrive lookup table and a second bit number as the number of bits of the current frame data defined in the overdrive lookup table is smaller than the number of bits of the input image data.

5. The display device according to claim 4, wherein The overdriver is configured to perform bit conversion on a bit number of the input image data into the first bit number or the second bit number. The display device according to claim 5 , wherein: The overdrive driver is configured to divide the multiple grayscale values of the current frame data included in the input image data into multiple intervals with unequal intervals, and perform the bit conversion by respectively mapping the multiple intervals to the multiple grayscale values of the current frame data defined in the overdrive lookup table.

7. The display device according to claim 6, wherein: The intervals in at least some of the plurality of intervals are set to be narrower as the grayscale value of the input image data is smaller.

8. The display device according to claim 4, wherein The first digit and the second digit are different.

9. The display device according to claim 8, wherein The overdriver is configured to perform the overdriving based on a size of the block and a difference between the first bit number and the second bit number.

10. The display device according to claim 9, wherein The overdriver is configured to perform the overdriving based on a value obtained by multiplying the size of the block by the difference value in response to the second bit number being greater than the first bit number.

11. The display device according to claim 9, wherein The overdriver is configured to perform the overdriving based on a value obtained by dividing the block size by the difference value in response to the second bit number being smaller than the first bit number.

12. A method for driving a display device, the method comprising: Get current frame data from input image data; Retrieve from the memory the block data of the previous frame generated by performing block averaging on the data of the previous frame and the overdrive lookup table; By referring to the overdrive lookup table, the current frame data is compared with the previous frame block data to generate overdrive frame data for the current frame data; generating an overdrive data signal based on the overdrive frame data; as well as supplying the overdrive data signal to a plurality of pixels, wherein generating the overdrive frame data comprises generating the overdrive frame data based on the size of the blocks divided for the block averaging, and The generating of the overdrive frame data includes generating the overdrive frame data according to a result obtained by comparing a value obtained by dividing the grayscale value of the current frame data by the size of the block with the grayscale value of the previous frame block data.

Images