Display driving circuit, its operation method, and operation method of MURA inspection device

Abstract

Provided are a display driving circuit configured to drive a display panel, an operation method thereof, and an operation method of an optical-based MURA inspection apparatus. The operation method of the display driving circuit configured to drive a display panel includes: receiving input data from an external device; determining a gray level period corresponding to the input data among a plurality of gray level periods based on a plurality of thresholds; calculating a final compensation value based on the determined gray level period and a reference look-up table generated based on a reference gray level; performing MURA compensation on the input data value based on the final compensation value to generate final data; and controlling the display panel based on the final data.

Description

[0001] Cross - reference to related applications

[0002] This application claims priority to Korean Patent Application No. 10 - 2020 - 0023408, filed with the Korean Intellectual Property Office on February 26, 2020, the disclosure of which is incorporated herein by reference in its entirety. Technical field

[0003] Embodiments of the present disclosure described herein relate to a display device, and more particularly, to a display driving circuit, an operation method of the display driving circuit, and an operation method of an optical - based MURA inspection device configured to extract information for compensating MURA of a display panel. Background art

[0004] A display device is a device configured to convert various information into a visual form to provide to a user. Generally, a display device includes a plurality of pixels configured to represent various information according to an electrical signal. In an ideal display panel, the plurality of pixels are configured to represent the same brightness when the same signal is provided to the plurality of pixels. However, due to various different environmental factors or manufacturing processes, the plurality of pixels of an actual display panel may not represent the same brightness in response to the same signal. This brightness imbalance may appear in the display panel in the form of stains (referred to as "MURA"). Summary of the invention

[0005] Embodiments of the present disclosure provide a display driving circuit configured to provide an image with improved quality by removing MURA of a display panel, an operation method of the display driving circuit, and an operation method of an optical - based MURA inspection device configured to extract information for compensating MURA of a display panel.

[0006] According to an exemplary embodiment, an operation method of a display driving circuit configured to drive a display panel includes: receiving input data from an external device; determining a gray - level period corresponding to the input data among a plurality of gray - level periods based on a plurality of thresholds; calculating a final compensation value based on the determined gray - level period and a reference look - up table generated according to a reference gray - level; performing MURA compensation on the input data based on the final compensation value to generate final data; and controlling the display panel based on the final data.

[0007] According to an exemplary embodiment, a display driving circuit configured to drive a display panel includes: a storage circuit that stores a plurality of thresholds and a reference look-up table generated based on a reference gray level; a MURA compensation circuit that receives input data from an external device, determines a gray level period corresponding to the input data among a plurality of gray level periods based on the plurality of thresholds, calculates a final compensation value based on the determined gray level period and the reference look-up table, and performs MURA compensation on the input data based on the calculated final compensation value to generate final data; a source driver that drives a plurality of source lines connected to the display panel; and a timing controller that controls the source driver based on the final data.

[0008] According to an exemplary embodiment, an operation method of an optical-based MURA inspection device configured to extract information for compensating MURA of a display panel includes: measuring reference optical information from a display panel controlled based on a reference gray level; generating a reference look-up table based on the reference optical information; storing the reference look-up table in a display driving circuit configured to control the display panel; generating a gray level pattern based on a plurality of gray levels that can be exhibited by the display panel; measuring supplementary optical information from the display panel controlled based on the gray level pattern; determining a plurality of thresholds for determining a plurality of gray level periods based on the gray level pattern and the supplementary optical information; and storing the plurality of thresholds in the display driving circuit.

[0009] According to an exemplary embodiment, an operation method of a display driving circuit configured to drive a display panel includes: performing first MURA compensation on input data from an external device by using a reference look-up table generated based on a reference gray level to generate first compensation data; determining a gray level period corresponding to the input data among a plurality of gray level periods based on a plurality of thresholds; calculating a supplementary compensation value based on the determined gray level period; performing second MURA compensation on the first compensation data based on the supplementary compensation value to generate final data; and controlling the display panel based on the final data. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The above and other objects and features of the present disclosure will become apparent by describing its exemplary embodiments in detail with reference to the accompanying drawings.

[0011] Figure 1 is a block diagram showing a display device according to an embodiment of the present disclosure.

[0012] FIGS. 2A to 2C are diagrams for describing an operation of extracting a reference look-up table stored in Figure 1 the storage circuit.

[0013] FIGS. 3A and 3B are graphs for describing a MURA compensation operation using a reference look-up table.

[0014] Figure 4 is a block diagram showing a MURA prevention system of a display panel according to an embodiment of the present disclosure.

[0015] Figure 5 is showing Figure 4 an operation flowchart of an optical-based MURA inspection device.

[0016] Figures 6A to 6C is a diagram for describing a configuration of a threshold value of an optical-based MURA inspection device.

[0017] Figure 7 is showing Figure 4 a MURA compensation operation flowchart of a display driving circuit.

[0018] Figure 8 is showing in detail Figure 1 a block diagram of a MURA compensation circuit.

[0019] Figure 9A and Figure 9B is showing in detail Figure 8 a diagram of a supplementary compensation value calculation module.

[0020] Figure 10 is for describing Figure 8 a MURA compensation effect of a MURA compensation circuit.

[0021] Figure 11 is showing Figure 4 an operation flowchart of an optical-based MURA inspection device.

[0022] Figure 12 is a block diagram showing a MURA prevention system of a display panel according to an embodiment of the present disclosure.

[0023] Figure 13 is showing included in Figure 12 a block diagram of a MURA compensation circuit in a display driving circuit.

[0024] Figure 14A and Figure 14B is showing Figure 13 a configuration diagram of a supplementary lookup table.

[0025] Figure 15 is a block diagram showing a MURA prevention system of a display panel according to an embodiment of the present disclosure.

[0026] Figure 16 is showing Figure 15 a block diagram of a display driving circuit.

[0027] Figure 17It is a block diagram showing a MURA compensation circuit of a display driving circuit according to an embodiment of the present disclosure.

[0028] Figure 18 It is shown Figure 17 a block diagram of a final compensation value calculation module.

[0029] Figure 19 It is shown Figure 17 a flowchart of the operation of a MURA compensation circuit of a display driving circuit.

[0030] Figure 20 It is a block diagram showing a display driving circuit according to an embodiment of the present disclosure.

[0031] Figure 21 It is a diagram for describing the operation of an optical-based MURA inspection device according to an embodiment of the present disclosure.

[0032] Figure 22 It is a block diagram showing an electronic device according to the present disclosure. Detailed Description of the Embodiments

[0033] Hereinafter, embodiments of the present disclosure can be described in detail and clearly to the extent that those of ordinary skill in the art can easily implement the present disclosure.

[0034] In the specification, components described by using terms such as "part", "unit", "module", etc. and functional blocks shown in the drawings can be implemented by software, hardware, or a combination thereof. For example, the software can be machine code, firmware, embedded code, or application software. For example, the hardware can include circuits, electronic circuits, processors, computers, integrated circuits, integrated circuit cores, pressure sensors, inertial sensors, microelectromechanical systems (MEMS), passive components, or a combination thereof.

[0035] Figure 1 It is a block diagram showing a display device according to an embodiment of the present disclosure. Referring to Figure 1 , the display device DPD may include a display driving integrated circuit (IC) or a display driving circuit (DDI) 100 and a display panel DP. The display device DPD may be included in an electronic device (such as a monitor, a television (TV), a tablet PC, a smartphone, or a navigation device) configured to provide various image information to a user.

[0036] The display panel DP can be connected to the row driver RD through a plurality of gate lines and can be connected to the display driving circuit 100 through a plurality of data lines. The display panel DP can include a plurality of pixels connected to the plurality of gate lines and the plurality of data lines. The plurality of pixels can be divided into a plurality of groups based on the color to be displayed. Each of the plurality of pixels can display one of the primary colors. The primary colors can include, but are not limited to, red, green, blue, and white. For example, the primary colors can also include various colors such as yellow, cyan, and magenta.

[0037] The display panel DP can include at least one of various types of panels (such as a liquid crystal display panel, an organic light emitting display panel, an electrophoretic display panel, and an electro-wetting display panel). However, the display panel DP according to the present disclosure is not limited thereto. For example, the display panel DP according to the present disclosure can be implemented with the above display panel or any other display panel. In an exemplary embodiment, the display panel DP including a liquid crystal display panel can further include a polarizer (not shown), a backlight unit (not shown), etc.

[0038] In order to output image information through the display panel DP, the display driving circuit 100 can control the row driver RD and can provide data signals through a plurality of data lines. In an exemplary embodiment, even if the display driving circuit 100 controls the display panel DP based on the same gray level, the brightness displayed and represented in the display panel DP may be irregular due to process variations, optical characteristics, etc. of the display panel DP. Such brightness irregularity or imbalance can cause display blotches (or referred to as "MURA").

[0039] The display driving circuit 100 can compensate for MURA occurring in the display panel DP. For example, the display driving circuit 100 can include a MURA compensation circuit 110, a storage circuit 120, a timing controller (TCON) 130, and a source driver 140.

[0040] The MURA compensation circuit 110 can perform a MURA compensation operation on the input data DT_in received from an external device (e.g., an application processor (AP) or a graphics processing unit (GPU)) based on a reference look-up table LUT_ref stored in the storage circuit 120. In an exemplary embodiment, the reference look-up table LUT_ref can be determined based on optical information, and the optical information can be measured based on a reference gray level among a plurality of gray levels that can be represented in the display panel DP. The optical information can be measured by a separate optical-based MURA inspection device. In an exemplary embodiment, the reference look-up table LUT_ref can be referred to as a "MURA map" or a "MURA look-up table". The configuration of the reference look-up table LUT_ref will be described more comprehensively with reference to the accompanying drawings below.

[0041] The MURA compensation circuit 110 may output the final data DT_fin as a result of the MURA compensation operation. In an exemplary embodiment, the MURA compensation circuit 110 may use the gamma value GV set by an external device in the above MURA compensation operation.

[0042] The timing controller 130 may receive the final data DT_fin from the MURA compensation circuit 110, and may control the source driver 140 based on the received final data DT_fin. The source driver 140 may control a plurality of data lines connected to the display panel DP under the control of the timing controller 130 or based on data provided from the timing controller 130 (e.g., DT_fin).

[0043] As described above, the display driving circuit 100 according to an embodiment of the present disclosure may include a MURA compensation circuit 110 configured to compensate for MURA occurring in the display panel DP. In an exemplary embodiment, the MURA compensation circuit 110 according to an embodiment of the present disclosure may perform a first MURA compensation operation based on a reference look-up table LUT_ref, and perform a second MURA compensation operation based on a supplementary compensation value determined according to the period of the input data DT_in. Alternatively, the MURA compensation circuit 110 according to an embodiment of the present disclosure may perform a MURA compensation operation based on a compensation value reprocessed or recalculated according to the period of the input data DT_in. The operation and configuration of the MURA compensation circuit 110 according to an embodiment of the present disclosure will be described more fully below with reference to the drawings.

[0044] FIGS. 2A to 2C are diagrams for describing an operation of extracting a reference look-up table stored in Figure 1 a storage circuit. FIG. 2A is a diagram showing an optical-based MURA inspection device configured to extract a reference look-up table. FIG. 2B is a graph showing a relationship between a gray level and a luminance of a specific pixel among a plurality of pixels included in a display panel. In FIG. 2B, the horizontal axis represents a gray level of input data provided to one pixel, and the vertical axis represents a luminance exhibited by one pixel. FIG. 2C is a diagram for describing a reference look-up table.

[0045] Hereinafter, for ease of description, it is assumed that the reference look-up table LUT_ref includes a reference correction value CV_ref for each of a plurality of pixels. The above assumption is made because the reference correction value CV_ref corresponds to one pixel, but the present disclosure is not limited thereto. For example, one reference correction value CV_ref may include correction values for a plurality of colors (e.g., "R", "G", and "B") corresponding to one pixel.

[0046] In addition, for the sake of brief description and ease of description, it is assumed that the gamma value GV provided from an external device is a preset value. That is, in the embodiments shown below or to be described below, the gamma value GV may be a specific value, that is, a fixed value, but the present disclosure is not limited thereto. For example, it can be understood that the gamma value GV changes under the control of an external device, and the shape of the gray level-brightness curve changes with the changed gamma value GV. The above examples are simple examples for easily describing the technical concept of the present disclosure, and the present disclosure is not limited thereto.

[0047] Referring to Figure 1 FIGS. 2C, the optical-based MURA inspection device 1 may extract a reference look-up table LUT_ref based on optical information (or image information) obtained or captured from the display panel DP. For example, the display driving circuit 100 may allow the display panel DP to exhibit a reference gray level GL_ref. The optical measurement unit 1a included in the optical-based MURA inspection device 1 may measure or capture reference optical information OP_ref from the display panel DP. The reference optical information OP_ref may indicate an image associated with the front surface of the display panel DP (i.e., a surface through which the output screen passes) controlled according to the reference gray level GL_ref. In this case, the display panel DP may be controlled to exhibit the reference gray level GL_ref, or the display panel DP may operate based on data corresponding to the reference gray level GL_ref.

[0048] The MURA information extraction unit 1b included in the optical-based MURA inspection device 1 may extract the reference look-up table LUT_ref based on the reference optical information OP_ref. For example, in FIG. 2B, the first curve indicates the gray level-brightness relationship associated with a specific pixel of the original display panel to which compensation is not applied, and the second curve indicates the gray level-brightness relationship associated with a pixel of an ideal display panel.

[0049] That is, with respect to the reference gray level GL_ref, a specific pixel among the plurality of pixels included in the display panel DP may exhibit a first brightness Lv1 like the first curve. However, with respect to the reference gray level GL_ref, a second brightness Lv2 may be exhibited by the ideal display panel like the second curve. That is, when data of the reference gray level GL_ref is provided to the display panel DP, a brightness imbalance corresponding to a brightness difference ΔLv may occur at a specific pixel of the display panel DP. That is, when data of the reference gray level GL_ref is provided to the display panel DP, MURA corresponding to the brightness difference ΔLv may occur at a specific pixel.

[0050] Therefore, MURA occurring at a specific pixel with respect to the reference gray level GL_ref can be removed or compensated by compensating for a luminance or input data as large as the luminance difference ΔLv. In an exemplary embodiment, the luminance difference ΔLv may correspond to the reference correction value CV_ref (CV_r in FIG. 2B) of a specific pixel.

[0051] With respect to the reference gray level GL_ref, the MURA information extraction unit 1b may detect the luminance difference for each of a plurality of pixels included in the display panel DP, and may extract or generate a reference look-up table LUT_ref as shown in FIG. 2C based on the detected luminance difference for each pixel. For example, as shown in FIG. 2C, it is assumed that the display panel DP includes a plurality of pixels PIX arranged in an 8×12 matrix (i.e., eight rows R1 to R8 and twelve columns C1 to C12), but the present disclosure is not limited thereto. In this case, the reference look-up table LUT_ref may include information on the reference correction value CV_ref for each of the plurality of pixels PIX. In an exemplary embodiment, the reference correction value CV_ref may be a value corresponding to the luminance difference occurring at the corresponding pixel where the data with the reference gray level GL_ref is provided.

[0052] With respect to the reference gray level GL_ref, the pixels at the first column C1 to the fourth column C4 of the first row R1, the eighth column C8 to the twelfth column C12 of the first row R1 may have a luminance difference from a reference luminance (e.g., Lv2 in FIG. 2B) corresponding to the first reference compensation value CV_ref1. With respect to the reference gray level GL_ref, the pixels at the fifth column C5 to the seventh column C7 of the first row R1, the second column C2 to the eleventh column C11 of the second row R2, and the third column C3, the fourth column C4, the ninth column C9, and the tenth column C10 of the third row R3 may have a luminance difference from a reference luminance corresponding to the second reference compensation value CV_ref2. Similarly, with respect to the reference gray level GL_ref, some of the plurality of pixels of the display panel DP may have a luminance difference from a reference luminance corresponding to the third reference compensation value CV_ref3 or the fourth reference compensation value CV_ref4. The above luminance differences may be manifested as a first MURA MURA1 and a second MURA MURA2 on the display panel DP.

[0053] The MURA information extraction unit 1b may detect the luminance difference as described above, and may extract the reference look-up table LUT_ref as shown in FIG. 2C based on the detected luminance difference.

[0054] In an exemplary embodiment, a plurality of reference correction values CV_ref of a reference look-up table LUT_ref may respectively correspond to a plurality of pixels included in a display panel DP. In an exemplary embodiment, the plurality of pixels may be configured to exhibit different colors (e.g., R, G, and B) in groups. That is, the plurality of reference correction values CV_ref may have values corresponding to a plurality of colors (e.g., R, G, and B).

[0055] In an exemplary embodiment, a plurality of pixels included in the display panel DP may be divided into given groups, and a plurality of reference correction values CV_ref of the reference look-up table LUT_ref may respectively correspond to the pixel groups. In this case, since the reference look-up table LUT_ref includes the reference correction values CV_ref corresponding to the pixel groups, the resources of the storage circuit 120 may be reduced. In an exemplary embodiment, the reference correction value CV_ref of a pixel group may be converted into a compensation value of a pixel unit through a recovery calculation operation such as interpolation.

[0056] FIGS. 3A and 3B are graphs for describing a MURA compensation operation using a reference look-up table. In the graphs of FIGS. 3A and 3B, the horizontal axis represents the gray level of a specific pixel among a plurality of pixels included in the display panel DP, and the vertical axis represents the luminance exhibited by the specific pixel among the plurality of pixels included in the display panel DP.

[0057] Referring to Figure 1 , FIGS. 3A and 3B, in the case where the MURA compensation operation is not performed (i.e., in the case of the original display panel), a specific pixel among the plurality of pixels of the display panel DP may exhibit the luminance of the first curve in FIGS. 3A and 3B at a plurality of gray levels. In the case where the MURA compensation operation is performed based on the reference look-up table LUT_ref or the reference correction value CV_ref, a specific pixel among the plurality of pixels of the display panel DP may exhibit the luminance of the third curve in FIGS. 3A and 3B at a plurality of gray levels.

[0058] For example, the MURA compensation operation based on the reference look-up table LUT_ref can be performed by changing the gray level value of the data to be provided to a specific pixel based on the reference compensation value CV_ref corresponding to the specific pixel among the multiple reference compensation values CV_ref of the reference look-up table LUT_ref. For example, like the first curve in FIG. 3A, a specific pixel may exhibit a luminance Lv_r when data of a reference gray level GL_ref is provided thereto. In this case, at the reference gray level GL_ref, the target luminance Lv_t may be exhibited by an ideal display panel like the second curve in FIG. 3A. Thus, when the input data DT_in of the specific pixel indicates the reference gray level GL_ref, the specific pixel may exhibit the target luminance Lv_t by adjusting the gray level of the input data DT_in of the specific pixel to the target gray level GL_t based on the reference compensation value CV_ref corresponding to the specific pixel. Based on the reference compensation value CV_ref of the above-mentioned reference look-up table LUT_ref, the above MURA compensation operation can be performed for each of the multiple pixels.

[0059] As described above, the MURA of the display panel DP can be compensated by performing the MURA compensation operation using the reference look-up table LUT_ref. In an exemplary embodiment, since the reference look-up table LUT_ref is extracted based on a reference gray level that is a specific gray level among the multiple gray levels that can be exhibited by the display panel DP, the MURA compensation performed with respect to the reference gray level can be relatively accurate. In contrast, the accuracy of the MURA compensation performed with respect to gray levels different from the reference gray level may be reduced.

[0060] For example, like the second curve in FIG. 3B, the luminance of the reference gray level GL_ref can be compensated to be substantially the same as the luminance of an ideal display panel (i.e., the second curve), but may be different from the luminance of the ideal display panel at the first gray level GL_1 and the second gray level GL_2 (i.e., the second curve). Specifically, in the case of performing MURA compensation based on the reference look-up table LUT_ref, the luminance value can be adjusted to a first luminance Lv1 at the first gray level GL_1, and the luminance can be adjusted to a second luminance Lv2 at the second gray level GL_2. However, the ideal luminance value associated with the first gray level GL_1 may be a first target luminance Lv_t1 that is brighter than the first luminance Lv1, and the ideal luminance value associated with the second gray level GL_2 may be a second target luminance Lv_t2 that is darker than the second luminance Lv2.

[0061] That is, in the case of MURA compensation based on the reference look-up table LUT_ref, the MURA compensation performed on the reference gray level GL_ref can be relatively accurate, while the MURA compensation performed on a gray level different from the reference gray level GL_ref may be relatively inaccurate. In other words, under a gray level different from the reference gray level GL_ref, weak compensation or strong compensation may occur. That is, when various gray levels are represented by the display panel DP, MURA may not be compensated or removed properly.

[0062] The MURA compensation circuit 110 of the display driving circuit 100 according to an embodiment of the present disclosure may perform a first MURA compensation operation based on the reference look-up table LUT_ref, may calculate a second compensation value based on the gray level period of the input data, and may perform a second MURA compensation operation on the result of the first MURA compensation operation based on the calculated second compensation value. Therefore, even when various gray levels are represented by the display panel DP, MURA occurring at the display panel DP can be compensated or removed properly, or luminance irregularities can be prevented.

[0063] Figure 4 FIG. is a block diagram showing a MURA prevention system of a display panel according to an embodiment of the present disclosure. For ease of description, additional descriptions related to the above components will be omitted to avoid redundancy. Referring to Figure 1 and Figure 4 , the optical MURA inspection device 10 may perform a MURA inspection operation for extracting or generating information required to compensate for MURA occurring at the display device DPD or the display panel DP. The optical MURA inspection device 10 may include an optical measurement unit 11, a MURA information extraction unit 12, a gray pattern generation unit 13, and a threshold determination unit 14.

[0064] The optical measurement unit 11 may measure reference optical information OP_ref received from the display panel DP controlled based on the reference gray level GL_ref, and the MURA information extraction unit 12 may extract the reference look-up table LUT_ref based on the reference optical information OP_ref. This has been described above, and thus, additional descriptions will be omitted to avoid redundancy.

[0065] The grayscale pattern generation unit 13 may generate a grayscale pattern GL_pat associated with a plurality of gray levels that can be represented by the display panel DP. For example, the grayscale pattern generation unit 13 may generate the grayscale pattern GL_pat such that the display panel DP sequentially and respectively represents specific gray levels. The specific gray levels may include a plurality of gray levels, or may include some gray levels sampled from the plurality of gray levels. The display driving circuit (DDI) 100 may control the display panel DP based on the grayscale pattern GL_pat received from the grayscale pattern generation unit 13.

[0066] The optical measurement unit 11 may measure supplementary optical information OP_sp from the display panel DP that sequentially represents a plurality of gray levels based on the grayscale pattern GL_pat. In an exemplary embodiment, the supplementary optical information OP_sp associated with the display panel DP may indicate image information corresponding to each of the plurality of gray levels included in the grayscale pattern GL_pat.

[0067] The threshold determination unit 14 may determine thresholds THs based on the supplementary optical information OP_sp received from the optical measurement unit 11 and information about the grayscale pattern GL_pat received from the grayscale pattern generation unit 13. In an exemplary embodiment, the thresholds THs may be values respectively corresponding to some of the plurality of gray levels, and may be used to determine the gray level period of the input data DT_in provided to the display driving circuit 100. The threshold determination unit 14 may store information about the determined thresholds THs in the display driving circuit 100 (e.g., the storage circuit 120). The configuration of the thresholds THs will be described more fully below with reference to the drawings.

[0068] In an exemplary embodiment, the display driving circuit 100 may perform a first MURA compensation operation on the input data DT_in based on a reference look-up table LUT_ref. Thereafter, the display driving circuit 100 may determine the gray level period of the input data DT_in based on the thresholds THs, and may also perform a second MURA compensation operation on the result of the first MURA compensation operation by using supplementary compensation values determined based on the determined gray level period. Accordingly, MURA occurring at various gray levels (i.e., MURA not removed by the first MURA compensation) described with reference to FIG. 3B may be normally removed.

[0069] Figure 5 is a flowchart showing Figure 4 the operation of the optical-based MURA inspection apparatus. Figures 6A to 6C is a diagram for describing the configuration of thresholds for determining an optical-based MURA inspection apparatus. In Figures 6A to 6C the graph, the horizontal axis represents the gray level, and the vertical axis represents the luminance. In Figures 6A to 6CIn the figure, the first curve indicates the gray level - luminance relationship associated with the display panel DP without MURA compensation applied, the second curve indicates the gray level - luminance relationship associated with an ideal display panel, and the third curve indicates the gray level - luminance relationship associated with the display panel DP with the first MURA compensation applied based on the reference look - up table LUT_ref. For the sake of brief illustration and convenience of description, additional descriptions regarding the above components will be omitted to avoid redundancy.

[0070] Referring to Figure 4 and Figure 5 In operation S111, the optical - based MURA inspection device 10 can measure the reference optical information OP_ref from the display panel DP controlled based on the reference gray level GL_ref. For example, the display driving circuit 100 can control the display panel DP based on the reference gray level GL_ref. In this case, the optical measurement unit 11 of the optical - based MURA inspection device 10 can measure the image information on the front surface of the display panel DP, that is, the reference optical information OP_ref.

[0071] In operation S112, the optical - based MURA inspection device 10 can extract the reference look - up table LUT_ref based on the reference optical information OP_ref. For example, the MURA information extraction unit 12 of the optical - based MURA inspection device 10 can detect the information (such as pixel positions) about the regions where luminance imbalance occurs and the luminance differences in the regions where luminance imbalance occurs based on the reference optical information OP_ref, and can extract the reference look - up table LUT_ref based on the detection results. The reference look - up table LUT_ref is described with reference to Figure 2C, so additional descriptions will be omitted to avoid redundancy.

[0072] In operation S113, the optical - based MURA inspection device 10 can store the extracted reference look - up table LUT_ref in the display driving circuit 100 (such as the storage circuit 120).

[0073] After that, in operation S121, the variable "k" can be set to "1". In an exemplary embodiment, the variable "k" is only used to describe the iterative operation of the optical - based MURA inspection device 10 and is not intended to limit the present disclosure.

[0074] In operation S122, the optical-based MURA inspection apparatus 10 may control the display driving circuit 100 based on the k-th gray level. In this case, the display driving circuit 100 may control the display panel DP based on the k-th gray level under the control of the optical-based MURA inspection apparatus 10. In this case, the display panel DP may output information corresponding to the k-th gray level. In an exemplary embodiment, in operation S122, the display driving circuit 100 may control the display panel DP based on data for which first MURA compensation is performed using the reference look-up table LUT_ref. That is, in operation S122, the gray level represented by the display panel DP may be a gray level to which first MURA compensation based on the reference look-up table LUT_ref is applied.

[0075] In operation S123, the optical-based MURA inspection apparatus 10 may measure the supplementary optical information OP_sp from the display panel DP. For example, the optical measurement unit 11 of the optical-based MURA inspection apparatus 10 may measure the supplementary optical information OP_sp from the display panel DP controlled based on the k-th gray level.

[0076] In operation S124, the optical-based MURA inspection apparatus 10 may determine whether the variable "k" is the maximum value. That is, the optical-based MURA inspection apparatus 10 may determine whether the supplementary optical information OP_sp is measured at each of a plurality of gray levels that can be represented by the display panel DP or at each of some predetermined gray levels (for example, gray levels sampled for a decision threshold among the plurality of gray levels).

[0077] When the variable "k" is not the maximum value, that is, when there are gray levels to be measured as the supplementary optical information OP_sp, in operation S125, the variable "k" may be incremented by "1", and the optical-based MURA inspection apparatus 10 may perform operation S122.

[0078] In an exemplary embodiment, operations S121 to S125 that constitute an iterative operation may be repeatedly performed by the optical measurement unit 11 and the grayscale pattern generation unit 13 of the optical-based MURA inspection device 10. For example, as described above, the grayscale pattern generation unit 13 may generate a grayscale pattern GL_pat such that all grayscale levels or some grayscale levels are sequentially presented through the display panel DP. The optical measurement unit 11 may measure supplementary optical information OP_sp associated with each of all grayscale levels or some grayscale levels of the display panel DP that sequentially presents all grayscale levels or some grayscale levels based on the grayscale pattern GL_pat. In this case, the display driving circuit 100 may perform first MURA compensation on the pattern data corresponding to the grayscale pattern GL_pat based on the reference look-up table LUT_ref, and may control the display panel DP based on the first compensated pattern data. That is, the supplementary optical information OP_sp measured based on the grayscale pattern GL_pat may correspond to the information on which the first MURA compensation based on the reference look-up table LUT_ref has been performed.

[0079] That is, in Figure 5 the flowchart of, the iterative operation obtains supplementary optical information OP_sp for each of all grayscale levels or for each of some grayscale levels; however, when using the grayscale pattern GL_pat generated by the grayscale pattern generation unit 13, the configuration for obtaining supplementary optical information OP_sp for each of all grayscale levels or for each of some grayscale levels may be performed by a single operation or by a single set of operations.

[0080] When the variable "k" is at its maximum value, that is, when there is no grayscale level to be measured as supplementary optical information OP_sp, in operation S126, the optical-based MURA inspection device 10 may determine a threshold THs based on the supplementary optical information OP_sp. In operation S127, the optical-based MURA inspection device 10 may store the determined threshold THs in the display driving circuit 100.

[0081] As a detailed example of operation S126, as Figure 6AAs shown in [reference], since the supplementary optical information OP_sp is image information obtained from the display panel DP to which the first MURA compensation based on the reference look-up table LUT_ref is applied, the supplementary optical information OP_sp can correspond to the third curve. The threshold determination unit 14 can obtain the information of the third curve based on the supplementary optical information OP_sp obtained from the display panel DP to which the first MURA compensation based on the reference look-up table LUT_ref is applied, and the threshold determination unit 14 can determine the threshold THs for determining the period of the input data DT_in based on the third curve and the second curve (i.e., the information about the ideal display panel).

[0082] As a detailed example, as Figure 6A shown in [reference], the threshold determination unit 14 of the optical-based MURA inspection device 10 can divide a plurality of gray levels (or the gray level of the input data DT_in) that can be represented by the display panel DP into a first gray level period RNG1 to a fifth gray level period RNG5 based on the supplementary optical information OP_sp (i.e., the third curve). The threshold determination unit 14 can determine the zeroth threshold TH0 to the fifth threshold TH5 for dividing the plurality of gray levels into the first gray level period RNG1 to the fifth gray level period RNG5.

[0083] In an exemplary embodiment, the display driving circuit 100 may determine a gray level period corresponding to the input data DT_in based on the input data DT_in and thresholds TH0 to TH5, and may perform a second MURA compensation operation based on a supplementary compensation value CV_sp corresponding to the determined gray level period. For example, when the input data DT_in is included between the zero threshold TH0 and the first threshold TH1, the display driving circuit 100 may perform the second MURA compensation operation based on the first supplementary compensation value CV_sp1; when the input data DT_in is included between the first threshold TH1 and the second threshold TH2, the display driving circuit 100 may perform the second MURA compensation operation based on the second supplementary compensation value CV_sp2; when the input data DT_in is included between the second threshold TH2 and the third threshold TH3, the display driving circuit 100 may perform the second MURA compensation operation based on the third supplementary compensation value CV_sp3; when the input data DT_in is included between the third threshold TH3 and the fourth threshold TH4, the display driving circuit 100 may perform the second MURA compensation operation based on the fourth supplementary compensation value CV_sp4; when the input data DT_in is included between the fourth threshold TH4 and the fifth threshold TH5, the display driving circuit 100 may perform the second MURA compensation operation based on the fifth supplementary compensation value CV_sp5. In an exemplary embodiment, the first supplementary compensation value CV_sp1 to the fifth supplementary compensation value CV_sp5 of the first gray level period RNG1 to the fifth gray level period RNG5 may be variable values determined by corresponding coefficients and variables. The second MURA compensation operation using the supplementary compensation value will be described more fully hereinafter with reference to the accompanying drawings.

[0084] In an exemplary embodiment, the threshold determination unit 14 may determine thresholds THs for determining the gray level period of the input data DT_in based on various information (such as the distance from the reference gray level GL_ref, the magnitude of the luminance difference (e.g., the absolute value of the luminance difference), and the polarity or direction of the luminance difference (e.g., the negative direction or the positive direction)). For example, Figure 6B and Figure 6C is a graph showing the luminance between the zero threshold TH0 and the second threshold TH2 with respect to the gray level. As Figure 6B shown, in the second gray level period RNG2 defined by the first threshold TH1 and the second threshold TH2, as the distance from the reference gray level GL_ref increases, for example, as the gray level decreases, the absolute value of the luminance difference ΔLv may increase.

[0085] Conversely, in the first gray level period RNG1 defined by the zero threshold TH0 and the first threshold TH1, as the distance from the reference gray level GL_ref increases, for example, as the gray level decreases, the absolute value of the luminance difference ΔLv may decrease.

[0086] In this case, the threshold determination unit 14 may determine the gray level of GL_a as the second threshold TH2, the gray level of GL_b as the first threshold TH1, and the gray level of GL_c as the zero threshold TH0. That is, as shown in Figure 6B , the threshold determination unit 14 may divide a plurality of gray levels into a plurality of periods based on the magnitude of the luminance difference according to the gray level distance.

[0087] Alternatively, as shown in Figure 6C , the threshold determination unit 14 may determine the thresholds TH0 and THa to THd in a specific gray level period or the entire gray level period. For example, in the period from THa to THc, as the distance from the reference gray level GL_ref increases, the absolute value of the luminance difference ΔLv may increase. In this case, in the period from THa to THb, the luminance difference ΔLv may be between the zero value m0 and the first value m1; in the period from THb to THc, the luminance difference ΔLv may be between the first value m1 and the second value m2. In this case, the threshold determination unit 14 may determine the period from THa to THb as one period and the period from THb to THc as another period. The threshold determination unit 14 may determine the thresholds THa, THb, and THc for determining the determined periods.

[0088] Similarly, in the period from THc to TH0, as the distance from the reference gray level GL_ref increases, the absolute value of the luminance difference ΔLv may decrease.

[0089] In this case, in the period from THc to THd, the luminance difference ΔLv may be between the first value m1 and the second value m2; in the period from THd to TH0, the luminance difference ΔLv may be between the zero value m0 and the first value m1. In this case, the threshold determination unit 14 may determine the period from THc to THd as one period and the period from THd to TH0 as another period. The threshold determination unit 14 may determine the thresholds THc, THd, and TH0 for determining the determined periods.

[0090] In an exemplary embodiment, in a case where "n" gray levels can be represented by the display panel DP. The plurality of gray level periods may be divided into "n" or fewer gray level periods.

[0091] As described above, the threshold determination unit 14 may determine a threshold THs for determining a period of the input data DT_in based on various information such as a distance from a reference gray level GL_ref, a magnitude of a luminance difference (i.e., an absolute value of the luminance difference), and a polarity or direction of the luminance difference (i.e., whether the luminance of the first MURA compensation is greater than a target luminance). In an exemplary embodiment, the various information may be obtained based on supplementary optical information OP_sp corresponding to each of all gray levels or some gray levels.

[0092] Figure 7 is a flowchart showing Figure 4 the MURA compensation operation of the display driving circuit. In an exemplary embodiment, according to Figure 7 the operations of the flowchart may indicate the MURA compensation operation in a normal operation of the display device DPD (e.g., an operation of an end user). That is, the information about the reference look-up table LUT_ref and the threshold THs described with reference to Figure 4 may be extracted during the manufacturing process of the display device DPD or during the inspection of the display device DPD at the optical-based MURA inspection device 10 described with reference to Figures 1 to 6C and the information may be stored in the display driving circuit 100. That is, before performing the operations of the flowchart of Figure 7 , the storage circuit 120 of the display driving circuit 100 may store the information about the reference look-up table LUT_ref and the threshold THs described with reference to Figures 1 to 6C .

[0093] For simplicity of explanation and description, hereinafter, it is assumed that the MURA compensation operation of the display driving circuit 100 is performed on a specific pixel among a plurality of pixels of the display panel DP. That is, hereinafter, the various information used in the MURA compensation may be information corresponding to a specific pixel among the plurality of pixels. However, the present disclosure is not limited thereto. The MURA compensation operation according to the embodiments of the present disclosure may be performed independently or non-independently on the plurality of pixels.

[0094] Referring to Figure 1 , Figure 4 and Figure 7, in operation S210, the display driving circuit 100 may perform first MURA compensation on the input data DT_in based on the reference compensation value CV_ref of the reference look-up table LUT_ref, and may generate first compensated data as a result of the first MURA compensation. For example, the MURA compensation circuit 110 of the display driving circuit 100 may perform a first MURA compensation operation on the input data DT_in based on the reference compensation value CV_ref of the reference look-up table LUT_ref. The MURA compensation operation (i.e., the first MURA compensation operation) based on the reference compensation value CV_ref of the reference look-up table LUT_ref has been described with reference to FIGS. 3A and 3B, and thus, additional description will be omitted to avoid redundancy.

[0095] In operation S220, the display driving circuit 100 may determine a gray level period corresponding to the input data DT_in based on the input data DT_in and the threshold THs. For example, as described above, the threshold THs may be used to determine whether the gray level of the input data DT_in is included in any of the plurality of gray level periods. The MURA compensation circuit 110 of the display driving circuit 100 may determine whether the gray level of the input data DT_in is included in any of the plurality of gray level periods defined by the threshold THs.

[0096] In operation S230, the display driving circuit 100 may generate a supplementary compensation value CV_sp corresponding to the determined gray level period based on the input data DT_in, the threshold THs, and the reference correction value CV_ref. For example, as described with reference to Figure 6A , the MURA compensation circuit 110 of the display driving circuit 100 may generate a supplementary compensation value CV_sp corresponding to the determined gray level period based on the input data DT_in, the threshold THs, and the reference correction value CV_ref. In an exemplary embodiment, the supplementary compensation value CV_sp may vary linearly or non-linearly according to the distance of the gray level of the input data DT_in (i.e., the difference from the reference gray level).

[0097] In operation S240, the display driving circuit 100 may perform supplementary MURA compensation (or second MURA compensation) on the first compensated data by using the supplementary compensation value CV_sp. For example, with reference to Figure 6A , in the case where the input data DT_in is included in the second gray level period RNG2, the supplementary compensation value may be determined as the second supplementary compensation value CV_sp2. In this case, the MURA compensation circuit 110 of the display driving circuit 100 may compensate or change the first compensated data (e.g., Figure 6AThe value (e.g., gray level) of the third curve) such that the brightness is increased by a second supplementary compensation value CV_sp2. Alternatively, in the case where the input data DT_in is included in the fourth gray level period RNG4, the supplementary compensation value may be determined as the fourth supplementary compensation value CV_sp4. In this case, the MURA compensation circuit 110 of the display driving circuit 100 may compensate or change the first compensated data (e.g., Figure 6A The value (e.g., gray level) of the third curve) such that the brightness is decreased by the fourth supplementary compensation value CV_sp4.

[0098] In operation S250, the display driving circuit 100 may output the result of the supplementary MURA compensation as the final data DT_fin. In an exemplary embodiment, the final data DT_fin may be provided to the timing controller 130 of the display driving circuit 100, and the timing controller 130 may control the source driver 140, the line driver RD, or the display panel DP based on the final data DT_fin.

[0099] That is, as described above, the display driving circuit 100 according to an embodiment of the present disclosure may perform a first MURA compensation operation on the input data DT_in based on the reference look-up table LUT_ref, and may subsequently perform supplementary MURA compensation based on the supplementary compensation value CV_sp determined according to the gray level period of the input data DT_in. That is, even when performing MURA compensation based on the reference look-up table LUT_ref, there is a problem that MURA cannot be properly compensated at gray levels other than the reference gray level. However, according to an embodiment of the present disclosure, since the second MURA compensation is performed based on the supplementary compensation value determined according to the gray level of the input data, the above problem can be avoided.

[0100] In an exemplary embodiment, in the case where the gray level of the input data DT_in is included in a period (e.g., the third gray level period RNG3) including the reference gray level GL_ref, the supplementary MURA compensation may be omitted (i.e., the third supplementary compensation value CV_sp3 is "0").

[0101] Figure 8 Is shown in detail Figure 1 The block diagram of the MURA compensation circuit. Figure 9A And Figure 9B Is shown in detail Figure 8 The diagram of the supplementary compensation value calculation module. For ease of description, additional descriptions associated with the above components will be omitted to avoid redundancy. Refer to Figure 1 、 Figure 8 、 Figure 9A And Figure 9B, the MURA compensation circuit 110 may include a first compensation module 111, a supplementary compensation value calculation module 112, and a second compensation module 113.

[0102] The first compensation module 111 may perform a first MURA compensation on the input data DT_in based on a reference look-up table LUT_ref. For example, the reference look-up table LUT_ref may include reference correction values CV_ref for each of a plurality of pixels or for each of pixel groups, and may be stored in the storage circuit 120. The input data DT_in may include gray level information for each of the plurality of pixels. The first compensation module 111 may perform a first MURA compensation on the input data DT_in based on the reference look-up table LUT_ref and the gray level information of the input data. The first MURA compensation based on the reference look-up table LUT_ref has been described with reference to FIGS. 3A and 3B, and thus, additional description will be omitted to avoid redundancy.

[0103] In an exemplary embodiment, the first compensation module 111 may perform a first MURA compensation based on a gamma value GV preset by an external device. For example, the shape of a curve indicating a gray level - brightness relationship (i.e., a gamma curve) may vary according to the gamma value GV. The first compensation module 111 may determine a reference compensation value CV_ref to be applied to the input data DT_in based on the gamma curve determined by the gamma value GV, and may perform a first MURA compensation on the input data DT_in based on the determined reference compensation value CV_ref.

[0104] The supplementary compensation value calculation module 112 may calculate a supplementary compensation value CV_sp based on the input data DT_in, a threshold THs stored in the storage circuit 120, and the reference look-up table LUT_ref. For example, the supplementary compensation value calculation module 112 may determine a gray level period including the gray level corresponding to the input data DT_in based on the threshold THs. The supplementary compensation value calculation module 112 may calculate a supplementary compensation value CV_sp to be used in a second MURA compensation to be performed on the data DT_1 that has undergone the first compensation based on information corresponding to the determined gray level period.

[0105] Specifically, as Figure 9A shown, the supplementary compensation value calculation module 112 may include a distance discriminator 112a, a period discriminator 112b, and a supplementary compensation value calculator 112c.

[0106] The distance discriminator 112a can determine the distance information dist based on the input data DT_in and the threshold THs. For example, assume that the gray level corresponding to a specific pixel of the input data DT_in indicates the first gray level. In this case, the distance discriminator 112a can output the distance between the first gray level and the reference gray level GL_ref, that is, the difference between the first gray level and the reference gray level GL_ref as the distance information dist. Alternatively, the distance discriminator 112a can output the distance between the first gray level and the corresponding threshold in the threshold THs as the distance information dist.

[0107] The period discriminator 112b can output the coefficient coef based on the input data DT_in and the threshold THs. For example, the period discriminator 112b can determine the gray level period including the gray level corresponding to the input data DT_in based on the threshold THs. The period discriminator 112b can output the coefficient coef corresponding to the determined gray level period. Specifically, when the gray level of the input data DT_in is included in Figure 6A the first gray level period RNG1 of Figure 6A the period discriminator 112b can output the first coefficient; when the gray level of the input data DT_in is included in

[0108] the fourth gray level period RNG4 of

[0109] the period discriminator 112b can output the fourth coefficient.

[0110] The supplementary compensation value calculator 112c can determine the supplementary compensation value CV_sp based on the reference compensation value CV_ref of the reference look-up table LUT_ref, the distance information dist from the distance discriminator 112a, and the coefficient coef from the period discriminator 112b. In an exemplary embodiment, the supplementary compensation value calculator 112c can calculate the supplementary compensation value CV_sp based on Equation 1 below.

[0111] [Equation 1]

[0112] CV_sp = CV_ref × (nor - coef × dist)

[0113] In Equation 1 above, "CV_sp" represents the supplementary compensation value, "CV_ref" represents the reference compensation value included in the reference look-up table LUT_ref, "coef" represents the coefficient determined by the period discriminator 112b, "dist" represents the information regarding the distance determined by the distance discriminator 112a, and "nor" represents the normalization factor. That is to say, as understood from Equation 1 above, the coefficient coef corresponding to each of the multiple gray-level periods can be determined, and the supplementary compensation value CV_sp can be determined based on the determined coefficient coef and the distance information dist. In this case, the supplementary compensation value CV_sp for the second MURA compensation can be calculated for each of the multiple gray-level periods.

[0114] In an exemplary embodiment, as Figure 9B shown, the supplementary compensation value calculation module 112-1 can include a distance discriminator 112a, a period discriminator 112b-1, and a supplementary compensation value calculator 112c. The distance discriminator 112a and the supplementary compensation value calculator 112c have been described above, and therefore, additional descriptions will be omitted to avoid redundancy. Different from Figure 9A the period discriminator 112b, Figure 9A the period discriminator 112b-1 can use the gamma value GV when selecting the coefficient coef of the gray-level period selected from the multiple gray-level periods. For example, as described above, at the same gray level, the target brightness can change non-linearly according to the change of the gamma value GV. Thus, the period discriminator 112b-1 can select the coefficient coef based on the gamma value GV, and therefore, the accuracy of the supplementary compensation value CV_sp can be improved.

[0115] Return to Figure 8, the second compensation module 113 can generate the final data DT_fin by performing a second MURA compensation on the data DT_1 that has undergone the first compensation based on the supplementary compensation value CV_sp from the supplementary compensation value calculation module 112. For example, the data that has undergone the first MURA compensation (i.e., the data DT_1 that has undergone the first compensation) may have the characteristics of the third curve described with reference to Figure 6A . That is, even if the first MURA compensation based on the reference look-up table LUT_ref is performed, the data DT_1 that has undergone the first compensation may still have characteristics different from those of an ideal display panel (i.e., Figure 6A 's second curve). That is, when controlling the display panel DP based on the data DT_1 that has undergone the first compensation, MURA or brightness imbalance may still occur.

[0116] In this case, the second compensation module 113 can generate the final data DT_fin by performing a second MURA compensation on the data DT_1 that has undergone the first compensation based on the supplementary compensation value CV_sp, thereby removing the brightness imbalance. For example, as shown in Figure 6A , when the gray level of the input data DT_in is included in the first gray level period RNG1 or the second gray level period RNG2, the second compensation module 113 can perform a second MURA compensation on the data DT_1 that has undergone the first compensation based on the first supplementary compensation value CV_sp1 or the second supplementary compensation value CV_sp2. Therefore, the brightness represented based on the input data DT_in can increase from the magnitude of the third curve to the magnitude of the second curve. Alternatively, when the gray level of the input data DT_in is included in the fourth gray level period RNG4 or the fifth gray level period RNG5, the second compensation module 113 can perform a second MURA compensation on the data DT_1 that has undergone the first compensation based on the fourth supplementary compensation value CV_sp4 or the fifth supplementary compensation value CV_sp5. Therefore, the brightness represented based on the input data DT_in can decrease from the magnitude of the third curve to the magnitude of the second curve. In an exemplary embodiment, when the gray level of the input data DT_in is included in the third gray level period RNG3 including the reference gray level GL_ref, the second compensation module 113 can omit the second MURA compensation. That is, the third supplementary compensation value CV_sp3 corresponding to the third gray level period RNG3 may correspond to "0".

[0117] That is, in Figure 6AIn an embodiment, the reference correction value CV_ref may have a negative polarity at all gray levels (i.e., perform the first MURA compensation in the direction of decreasing brightness). However, the first supplementary compensation value CV_sp1 and the second supplementary compensation value CV_sp2 may have a positive polarity in the first gray level period RNG1 and the second gray level period RNG2 (i.e., perform the second MURA compensation in the direction of increasing brightness), and the fourth supplementary compensation value CV_sp4 and the fifth supplementary compensation value CV_sp5 may have a negative polarity in the fourth gray level period RNG4 and the fifth gray level period RNG5 (i.e., perform the second MURA compensation in the direction of decreasing brightness). In other words, at all gray levels, the first MURA compensation using the reference lookup table may be performed in one of the direction of decreasing brightness and the direction of increasing brightness, but the second MURA compensation according to the embodiments of the present disclosure may be performed in the direction of decreasing brightness or the direction of increasing brightness according to the gray level period.

[0118] An example in which the reference correction value CV_ref is of negative polarity is described in the drawings. However, the present disclosure is not limited thereto. For example, the reference correction value CV_ref corresponding to a positive polarity or a negative polarity may be set for each of a plurality of pixels.

[0119] As described above, the conventional MURA compensation circuit only performs the first MURA compensation based on the reference lookup table LUT_ref. In this case, since the reference lookup table LUT_ref is information extracted based on the reference gray level GL_ref, the MURA compensation performed on the reference gray level GL_ref may be relatively accurate. However, over-compensation or under-compensation may occur at the remaining gray levels, resulting in the problem that MURA cannot be removed normally.

[0120] The display driving circuit 100 according to an embodiment of the present disclosure may determine a gray level period including the gray level of the input data DT_in based on a threshold THs pre-determined by the optical-based MURA inspection device 10, and may perform a second MURA compensation on the data after the first compensation (i.e., the data DT_1 after the first compensation) based on a supplementary compensation value CV_sp corresponding to the determined gray level period. Therefore, the performance of MURA compensation or the quality of the image to be displayed can be improved at all gray levels that can be represented by the display panel DP.

[0121] Figure 10 is used to describe according to Figure 8Diagram showing the MURA compensation effect of the MURA compensation circuit. For the sake of brief explanation and for ease of description, components that are not required to describe the MURA compensation effect are omitted. For ease of description, MURA compensation is performed on optical information, but the present disclosure is not limited thereto. For example, the fact that compensated optical information is generated by performing MURA compensation on specific optical information means that MURA compensation is performed on data corresponding to the specific optical information, and the optical information corresponding to the MURA-compensated data is measured.

[0122] Referring to Figure 1 、 Figure 8 and Figure 10 , input optical information OP_in corresponding to the input data DT_in can be obtained. For example, the display driving circuit 100 can control the display panel DP based on the input data DT_in without separate MURA compensation. The input optical information OP_in can be image information obtained from the display panel DP controlled without MURA compensation. As Figure 10 shown, the input optical information OP_in may include a MURA region. In an exemplary embodiment, the gray level corresponding to the input optical information OP_in (i.e., the gray level corresponding to the input data DT_in) may be different from the reference gray level GL_ref corresponding to the reference look-up table LUT_ref.

[0123] To compensate for the MURA region included in the input optical information OP_in, the first MURA compensation can be performed based on the reference look-up table LUT_ref. Compensated data DT_1 can be generated as a result of the first MURA compensation, and first-compensated optical information OP_1 corresponding to the compensated data DT_1 can be obtained. In this case, even though the first MURA compensation is performed based on the reference look-up table LUT_ref, the first-compensated optical information OP_1 may include a MURA region. That is, there is a region where the MURA is not compensated properly.

[0124] In this case, the display driving circuit 100 according to an embodiment of the present disclosure can generate final data DT_fin by generating a supplementary compensation value CV_sp based on the input data DT_in, a threshold THs, and the reference look-up table LUT_ref and performing a second MURA compensation on the compensated data DT_1 based on the generated supplementary compensation value CV_sp. The final optical information OP_fin can correspond to the final data DT_fin. In this case, as Figure 10As shown, luminance imbalance (i.e., MURA) does not occur under the final optical information OP_fin. That is, as described above, since the second MURA compensation based on the supplementary compensation value CV_sp is performed on the existing MURA regions even after the first MURA compensation, luminance imbalance does not occur under the final optical information OP_fin.

[0125] Figure 11 is a flowchart showing Figure 4 the operation of an optical-based MURA inspection device. For ease of description, additional descriptions associated with the above components will be omitted to avoid redundancy. Referring to Figure 4 and Figure 11 , the optical-based MURA inspection device 10 can perform operations S311 to S313. Operations S311 to S313 are similar to Figure 5 operations S111 to S113 of

[0126] , and thus, additional descriptions will be omitted to avoid redundancy.

[0126] In operation S321, the optical-based MURA inspection device 10 can determine a threshold based on a predetermined period. For example, according to Figure 5 the flowchart of Figure 11 , the optical-based MURA inspection device 10 can obtain supplementary optical information OP_sp through iterative operations performed for each of multiple gray levels, and can determine a threshold THs based on the supplementary optical information OP_sp. Conversely, according to Figure 11 , the optical-based MURA inspection device 10 can omit the operation of obtaining supplementary optical information OP_sp, and can determine a threshold THs based on a preset period. In an exemplary embodiment, the predetermined preset period can be a period predetermined through MURA inspection operations performed on other display panels. Alternatively, the preset periods can have the same length.

[0127] In operation S322, the optical-based MURA inspection device 10 can store the determined threshold THs in the display driving circuit 100. In an exemplary embodiment, the optical-based MURA inspection device 10 can store information about coefficients coef (refer to Figure 9A and Figure 9B ) corresponding to each of multiple periods in the display driving circuit 100.

[0128] Figure 12 is a block diagram showing a MURA prevention system of a display panel according to an embodiment of the present disclosure. For ease of description, additional descriptions associated with the above components will be omitted to avoid redundancy. Referring to Figure 12, the optical-based MURA inspection apparatus 20 may include an optical measurement unit 21, a MURA information extraction unit 22, a grayscale pattern generation unit 23, a threshold determination unit 24, and a supplementary MURA information extraction unit 25.

[0129] The optical-based MURA inspection apparatus 20 may measure reference optical information OP_ref from a display panel DP controlled based on a reference grayscale level GL_ref, and may extract a reference look-up table LUT_ref based on the measured reference optical information OP_ref. The thus-extracted reference look-up table LUT_ref may be stored in a display driver circuit (DDI) 200. The optical-based MURA inspection apparatus 20 may generate a grayscale pattern GL_pat, and the display driver circuit 200 may control the display panel DP based on the grayscale pattern GL_pat. The optical-based MURA inspection apparatus 20 may measure supplementary optical information OP_sp received from the display panel DP controlled based on the grayscale pattern GL_pat, the threshold determination unit 24 may determine a threshold THs based on the supplementary optical information OP_sp, and the determined threshold THs may be stored in the display driver circuit 200. The optical measurement unit 21, the MURA information extraction unit 22, the grayscale pattern generation unit 23, and the threshold determination unit 24 and their operations have been described above, and thus, additional descriptions will be omitted to avoid redundancy.

[0130] In an exemplary embodiment, Figure 12 the optical-based MURA inspection apparatus 20 may further include a supplementary MURA information extraction unit 25. The supplementary MURA information extraction unit 25 may extract a supplementary look-up table LUT_sp based on the supplementary optical information OP_sp. In an exemplary embodiment, the supplementary look-up table LUT_sp may include information on supplementary compensation values CV_sp for each of a plurality of pixels of the display panel DP. In an exemplary embodiment, the supplementary look-up table LUT_sp may include information related to the supplementary compensation values CV_sp for each of a plurality of grayscale periods. The supplementary look-up table LUT_sp may be stored in the display driver circuit 200.

[0131] In an exemplary embodiment, the supplementary compensation values CV_sp included in the supplementary look-up table LUT_sp may be determined in advance based on the method described with reference to Figures 1 to 11 That is, the display driver circuit 200 may select the supplementary compensation value CV_sp from the supplementary look-up table LUT_sp according to the grayscale period of the input data DT_in without separately calculating the supplementary look-up table LUT_sp, and may perform second MURA compensation based on the selected supplementary compensation value CV_sp.

[0132] Figure 13is a block diagram showing a MURA compensation circuit included in Figure 12 of a display driving circuit. Figure 14A and Figure 14B is a diagram showing the configuration of a supplementary lookup table of Figure 13 . Referring to Figure 12 , Figure 13 , Figure 14A and Figure 14B , the MURA compensation circuit 210 of the display driving circuit 200 may include a first compensation module 211, a supplementary compensation value determination module 212, and a second compensation module 213. The reference lookup table LUT_ref, the supplementary lookup table LUT_sp, and the threshold THs may be included in the storage circuit 220 of the display driving circuit 200. The first compensation module 211 and the second compensation module 213 are similar to those described with reference to Figure 8 , and thus, additional descriptions will be omitted to avoid redundancy.

[0133] The supplementary compensation value determination module 212 may determine a supplementary compensation value CV_sp from the supplementary lookup table LUT_sp based on the input data DT_in and the threshold THs. For example, the supplementary lookup table LUT_sp may include a supplementary compensation value CV_sp for each of a plurality of gray level cycles. Specifically, as shown in Figure 14A and Figure 14B , the supplementary lookup table may include a first supplementary lookup table LUT_sp1 and a second supplementary lookup table LUT_sp2.

[0134] The first supplementary lookup table LUT_sp1 may include a supplementary compensation value corresponding to a first gray level cycle RNG1 (see Figure 6A ) for each of a plurality of pixels PIX. For example, in a case where the gray level of the input data DT_in is included in the first gray level cycle RNG1, the first supplementary lookup table LUT_sp1 may include information about a supplementary compensation value to be used in a second MURA compensation.

[0135] In this case, the supplementary compensation values constituting the first supplementary lookup table LUT_sp1 may be different from the reference correction values of the reference lookup table LUT_ref (see FIG. 2C). That is, as shown in FIG. 2C, a first MURA MURA1 and a second MURA MURA2 may occur in the display panel DP at a reference gray level GL_ref, and the reference lookup table LUT_ref may include information about reference compensation values CV_ref1 to CV_ref4 applied to regions where the first MURA MURA1 and the second MURA MURA2 occur.

[0136] In contrast, the first supplementary lookup table LUT_sp1 may include supplementary compensation values CV_spa to CV_spd corresponding to regions where MURA occurs at gray levels (different from the reference gray level GL_ref) included in the first gray level period RNG1 after the first MURA compensation. That is, in the reference lookup table LUT_ref, even if the reference compensation values CV_ref for the pixels at the first row R1 and first column C1 and the first row R1 and twelfth column C12 are the same as the first reference compensation value CV_ref1 at the gray levels included in the first gray level period RGN1, the luminance differences of the pixels at the first row R1 and first column C1 and the first row R1 and twelfth column C12 may be different after performing the first MURA compensation. That is to say, after performing the first MURA compensation based on the reference lookup table LUT_ref, the pixel at the first row R1 and first column C1 may have a luminance difference corresponding to the fourth supplementary compensation value CV_spd, and the luminance difference may not occur at the pixel at the first row R1 and twelfth column C12.

[0137] For example, in the case where the input data DT_in has a gray level included in the first gray level period RNG1, for each pixel, the first supplementary lookup table LUT_sp1 may include information about the supplementary compensation values to be used in the second MURA compensation.

[0138] Similarly, as Figure 14B shown, for each of the plurality of pixels PIX, the second supplementary lookup table LUT_sp2 may include supplementary compensation values CV_spa to supplementary compensation value CV_spd corresponding to the fifth gray level period RNG5 (see Figure 6A ). Except that the gray level periods are different and the corresponding supplementary compensation values are different, the configuration of the second supplementary lookup table LUT_sp2 is similar to the configuration of the above-mentioned first supplementary lookup table LUT_sp1.

[0139] In an exemplary embodiment, the first supplementary lookup table LUT_sp1 and the second supplementary lookup table LUT_sp2 may be stored in the storage circuit 220, or may be calculated based on the reference lookup table LUT_ref stored in the storage circuit 220. That is to say, the storage circuit 220 may only store the reference lookup table LUT_ref; in this case, a separate calculation module may calculate the first supplementary lookup table LUT_sp1 and the second supplementary lookup table LUT_sp2 based on the reference lookup table LUT_ref. In this case, the separate calculation module may generate or calculate the supplementary lookup table LUT_sp based on the reference lookup table LUT_ref and various information (such as the coefficient information, distance information, or period information described above).

[0140] As described above, the display driving circuit 200 may include at least one supplementary look-up table LUT_sp, which includes supplementary compensation values CV_sp for each of a plurality of gray levels or for each of a plurality of gray level cycles. In this case, the display driving circuit 200 may be configured to select corresponding supplementary compensation values from the supplementary look-up table LUT_sp without separately calculating the supplementary compensation values CV_sp for second MURA compensation. In an exemplary embodiment, the supplementary look-up table LUT_sp may be determined by a pre-inspection of the optical-based MURA inspection device 20.

[0141] Figure 15 is a block diagram of a MURA prevention system for a display panel according to an embodiment of the present disclosure. Figure 16 is shown Figure 15 of the display driving circuit. Referring to Figure 15 , the optical-based MURA inspection device 30 may include an optical measurement unit 31, a MURA information extraction unit 32, a gray level pattern generation unit 33, and a functional model generation unit 34. The optical-based MURA inspection device 30 may measure reference optical information OP_ref from the display panel DP controlled based on a reference gray level GL_ref, and may extract a reference look-up table LUT_ref based on the measured reference optical information OP_ref. The thus-extracted reference look-up table LUT_ref may be stored in the display driving circuit (DDI) 300. The optical-based MURA inspection device 30 may generate a gray level pattern GL_pat, and the display driving circuit 300 may control the display panel DP based on the gray level pattern GL_pat. The optical-based MURA inspection device 30 may measure supplementary optical information OP_sp from the display panel DP controlled based on the gray level pattern GL_pat. The optical measurement unit 31, the MURA information extraction unit 32, and the gray level pattern generation unit 33 have been described above, and thus, additional descriptions will be omitted to avoid redundancy.

[0142] The functional model generation unit 34 may generate a functional model FT based on the supplementary optical information OP_sp. For example, the supplementary optical information OP_sp may have characteristics corresponding to the third curve described with reference to Figure 6A (i.e., data after first MURA compensation obtained by performing first MURA compensation based on the reference look-up table LUT_ref). The functional model generation unit 34 may generate, learn, extract, or model a functional model having the Figure 6A characteristics of the third curve based on the supplementary optical information OP_sp. That is, the functional model FT may be configured to output Figure 6Acharacteristics of the third curve (i.e., the data after the first MURA compensation obtained by performing the first MURA compensation based on the reference look-up table LUT_ref).

[0143] Information about the functional model FT can be stored in the display driving circuit 300. For example, as Figure 16 shown, the MURA compensation circuit 310 of the display driving circuit 300 may include a first compensation module 311, a functional model module 312, and a second compensation module 313. The first compensation module 311 and the second compensation module 313 have been described above, and thus, additional descriptions will be omitted to avoid redundancy.

[0144] The functional model module 312 may include the functional model FT generated by the functional model generation unit 34 of the optical-based MURA inspection device 30. The functional model module 312 may be configured to output a supplementary compensation value CV_sp based on the input data DT_in and the reference correction value CV_ref of the reference look-up table LUT_ref. For example, as described above, the functional model FT may be a model obtained by modeling the gray level-brightness information after performing the first MURA compensation. That is, the data DT_1 after the first compensation corresponding to the input data DT_in can be judged by the functional model FT, and thus, the supplementary compensation value CV_sp to be used in the second MURA compensation can be judged. That is, the MURA compensation circuit 310 of the display driving circuit 300 can continuously, linearly, or non-linearly judge the supplementary compensation value CV_sp through the functional model FT, rather than determining the gray level period of the input data DT_in.

[0145] Figure 17 is a block diagram showing a MURA compensation circuit of a display driving circuit according to an embodiment of the present disclosure. Figure 18 is a diagram showing Figure 17 a block diagram of the final compensation value calculation module. For ease of description, additional descriptions associated with the above components will be omitted to avoid redundancy.

[0146] Referring to Figure 17 and Figure 18 , the MURA compensation circuit 410 may include a final compensation value (CV_f) calculation module 412 and a compensation module 413. The reference look-up table LUT_ref and the threshold THs may be included in the storage circuit 420. The reference look-up table LUT_ref and the threshold THs may be pre-stored in the storage circuit 420 through the inspection operation of the optical-based MURA inspection device based on the method described with reference to Figures 1 to 11 the above.

[0147] The compensation module 413 may perform a second MURA compensation operation on the input data DT_in based on the final compensation value CV_fin from the final compensation value calculation module 412 to output the final data DT_fin. In the above embodiments, the first MURA compensation and the second MURA compensation are described as being performed by the MURA compensation circuit. However, in Figure 17 In the embodiment of, the MURA compensation circuit 410 may perform MURA compensation once. In this case, the MURA compensation circuit 410 may perform MURA compensation based on the final compensation value CV_fin recalculated or reprocessed according to the gray level period of the input data DT_in instead of the reference correction value CV_ref.

[0148] For example, the final compensation value calculation module 412 may output the final compensation value CV_fin based on the threshold THs and the reference correction value CV_ref of the reference look-up table LUT_ref. Specifically, as Figure 18 shown in, the final compensation value calculation module 412 may include a distance discriminator 412a, a period discriminator 412b, a supplementary compensation value calculator 412c, and a final compensation value calculator 412d. The distance discriminator 412a may discriminate the distance information dist based on the input data DT_in and the threshold THs, the period discriminator 412b may discriminate the coefficient coef based on the input data DT_in and the threshold THs, and the supplementary compensation value calculator 412c may discriminate the supplementary compensation value CV_sp based on the distance information dist, the coefficient coef, and the reference compensation value CV_ref. The distance discriminator 412a, the period discriminator 412b, and the supplementary compensation value calculator 412c have been described above, and thus, additional descriptions will be omitted to avoid redundancy.

[0149] The final compensation value calculator 412d may combine the supplementary compensation value CV_sp and the reference correction value CV_ref to generate the final compensation value CV_fin. That is, the final compensation value CV_fin may include information on the supplementary compensation value CV_sp and the reference correction value CV_ref. When performing MURA compensation on the input data DT_in by using the final compensation value CV_fin, the effects of the first MURA compensation and the second MURA compensation may appear the same.

[0150] Although not shown in the drawings, the period discriminator 412b or the final compensation value calculator 412d may use the gamma value GV discriminated by an external device when calculating the coefficient coef or the final compensation value CV_fin. This is similar to the above description, and thus, additional descriptions will be omitted to avoid redundancy.

[0151] As described above, the display driving circuit according to an embodiment of the present disclosure may calculate a supplementary compensation value to be used in second MURA compensation based on a gray level period of input data. When the display driving circuit performs second MURA compensation by using the supplementary compensation value, the display driving circuit may normally compensate / remove MURA (i.e., an area where strong compensation or weak compensation occurs) that is not normally compensated in the first MURA compensation by simply using a reference look-up table. Therefore, luminance imbalance can be prevented at multiple gray levels that can be represented by the display panel DP.

[0152] Figure 19 is a flowchart showing Figure 17 the operation of the MURA compensation circuit of the display driving circuit. For ease of description, additional descriptions associated with the above components will be omitted to avoid redundancy.

[0153] Referring to Figure 17 and Figure 19 , in operation S410, the MURA compensation circuit 410 may receive input data.

[0154] In operation S420, the MURA compensation circuit 410 may determine a gray level period corresponding to the input data based on the input data and a threshold THs.

[0155] In operation S430, the MURA compensation circuit 410 may calculate a final compensation value CV_fin based on the determined gray level period and a reference look-up table LUT_ref. For example, as described with reference to Figure 17 and Figure 18 , the MURA compensation circuit 410 may calculate the final compensation value CV_fin for each gray level period corresponding to the gray level of the input data by using different coefficients. In this case, a more accurate compensation value than a compensation value (e.g., a first compensation value) calculated by simply using the reference look-up table LUT_ref can be calculated.

[0156] In operation S440, the MURA compensation circuit 410 may perform MURA compensation on the input data based on the final compensation value CV_fin. In operation S450, the MURA compensation circuit 410 may output the result of the MURA compensation (i.e., compensated data).

[0157] As described above, instead of simply calculating the compensation value through linear calculation based on the reference look-up table LUT_ref, the MURA compensation circuit 410 according to an embodiment of the present disclosure can determine a gray level period corresponding to the gray level of the input data based on a predetermined threshold THs, and can calculate the final compensation value CV_fin by using different coefficients according to the determined gray level period (i.e., the compensation value can be calculated through non-linear calculation). Therefore, luminance imbalance can be prevented at multiple gray levels that can be represented by the display panel DP.

[0158] Figure 20 is a block diagram showing a display driving circuit according to an embodiment of the present disclosure. Referring to Figure 20 , the display driving circuit 1000 may include a MURA compensation circuit 1100, a storage circuit 1200, a timing controller (TCON) 1300, a source driver 1400, and a gamma correction circuit 1500. The MURA compensation circuit 1100 may be the MURA compensation circuit described with reference to Figures 1 to 18 , or may operate based on the operation method described with reference to Figures 1 to 18 . The storage circuit 1200 may be configured to store a reference look-up table LUT_ref, a threshold THs, a supplementary look-up table LUT_sp, a functional model FT, etc. generated by the optical-based MURA inspection devices 10, 20, or 30 as described with reference to Figures 1 to 18 . The MURA compensation circuit 1100, the storage circuit 1200, the timing controller 1300, and the source driver 1400 have been described above, and thus, additional descriptions will be omitted to avoid redundancy.

[0159] The gamma correction circuit 1500 of the display driving circuit 1000 may be configured to correct the gamma characteristics of the gray levels that can be represented by the display panel DP (see Figure 1 ), that is, perform gamma correction. For example, the luminance of the same gray level may be differently represented according to the gamma value GV. The gamma correction circuit 1500 may generate a gamma reference voltage VG_ref based on the gamma value GV. The source driver 1400 may control the display panel DP based on the gamma reference voltage VG_ref from the gamma correction circuit 1500.

[0160] In an exemplary embodiment, as described above, the MURA compensation circuit 410 may use the gamma value GV when performing the first MURA compensation or the second MURA compensation, but the gamma correction according to the gamma value GV may be performed by the gamma correction circuit 1500 after the MURA compensation circuit 1100. In an exemplary embodiment, gamma correction may be pre-executed by a separate module in front of the MURA compensation circuit 1100 according to the method of implementing the display driving circuit 1000.

[0161] Figure 21 is a diagram for describing the operation of an optical-based MURA inspection apparatus according to an embodiment of the present disclosure. Refer to Figure 21 , the optical-based MURA inspection system 2000 may include a display panel group GR_DP, a display driving circuit group GR_DDI, and an optical-based MURA inspection apparatus 2100. One display panel group GR_DP may include a plurality of display panels, and one display driving circuit group GR_DDI may include a plurality of display driving circuits.

[0162] A plurality of display devices DPD may be implemented by allowing the plurality of display panels included in the display panel group GR_DP to respectively correspond to the plurality of display driving circuits included in the display driving circuit group GR_DDI or by allowing the plurality of display panels and the plurality of display driving circuits to be connected to each other in a one-to-one correspondence.

[0163] In each of the plurality of display devices DPD, the optical-based MURA inspection apparatus 20 may generate a reference look-up table LUT_ref, thresholds THs, a supplementary look-up table LUT_sp, or a functional model FT based on the operation method described with reference to Figures 1 to 20 and may store the generated information in the corresponding display driving circuit.

[0164] In an exemplary embodiment, the plurality of display panels included in the display panel group GR_DP may be generated in the same process line, and the plurality of display driving circuits included in the display driving circuit group GR_DDI may be manufactured in the same process line. That is, the display panels or the display driving circuits included in the same group may have the same physical / electrical characteristics. This means that the MURA patterns are similar.

[0165] Thus, in order to simplify the MURA inspection process, for a sample display panel DP_samp of the display panels of the display panel group GR_DP and a sample display driving circuit DDI_samp of the display driving circuits of the display driving circuit group GR_DDI, the optical-based MURA inspection apparatus 2100 may generate a reference look-up table LUT_ref, thresholds THs, a supplementary look-up table LUT_sp, or a functional model FT as MURA_info based on the operation method described with reference to Figures 1 to 20 and may store the generated information in the display driving circuits included in the same group. Each of the display driving circuits may perform the operation described with reference to Figures 1 to 20 based on the stored information.

[0166] Figure 22 is a block diagram showing an electronic device according to the present disclosure. Refer to Figure 22, the electronic device 3000 may include a main processor 3100, a touch panel 3200, a touch driving circuit (TDI) 3202, a display panel 3300, a display driving circuit (DDI) 3302, a system memory 3400, a storage device 3500, an audio processor 3600, a communication block 3700, and an image processor 3800. In an exemplary embodiment, the electronic device 3000 may be one of various electronic devices, such as a portable communication terminal, a personal digital assistant (PDA), a portable media player (PMP), a digital camera, a smart phone, a tablet PC, a laptop computer, and a wearable device.

[0167] The main processor 3100 may control the overall operation of the electronic device 3000. The main processor 3100 may control / manage the operations of the components of the electronic device 3000. The main processor 3100 may process various operations for operating the electronic device 3000.

[0168] The touch panel 3200 may be configured to sense a touch input from a user under the control of the touch driving circuit 3202. The display panel 3300 may be configured to display image information under the control of the display driving circuit 3302. In an exemplary embodiment, the display driving circuit 3302 may be configured to compensate for MURA occurring at the display panel 3300 based on the method described with reference to Figures 1 to 20 Although not shown in the drawings, the touch panel 3200 and the display panel 3300 may be implemented with one panel, and the touch driving circuit 3202 and the display driving circuit 3302 may be implemented with one integrated circuit.

[0169] The system memory 3400 may store data for the operation of the electronic device 3000. For example, the system memory 3400 may include volatile memory (such as static random access memory (SRAM), dynamic RAM (DRAM), or synchronous DRAM (SDRAM)) and / or non-volatile memory (such as phase change RAM (PRAM), magnetoresistive RAM (MRAM), resistive RAM (ReRAM), or ferroelectric RAM (FRAM)).

[0170] The storage device 3500 may store data regardless of whether power is supplied. For example, the storage device 3500 may include at least one of various non-volatile memories (such as flash memory, PRAM, MRAM, ReRAM, and FRAM). For example, the storage device 3500 may include an embedded memory and / or a removable memory of the electronic device 3000.

[0171] The audio processor 3600 can process an audio signal by using the audio signal processor 3610. The audio processor 3600 can receive an audio input through the microphone 3620, or can provide an audio output through the speaker 3630.

[0172] The communication block 3700 can exchange signals with an external device / system through the antenna 3710. The transceiver 3720 and the modulator / demodulator (MODEM) 3730 of the communication block 3700 can process the signals exchanged with the external device / system according to at least one of the following various wireless communication protocols: Long Term Evolution (LTE), Worldwide Interoperability for Microwave Access (WiMax), Global System for Mobile Communications (GSM), Code Division Multiple Access (CDMA), Bluetooth, Near Field Communication (NFC), Wireless Fidelity (Wi-Fi), and Radio Frequency Identification (RFID).

[0173] The image processor 3800 can receive light through the lens 3810. The image device 3820 and the image signal processor (ISP) 3830 included in the image processor 3800 can generate image information about an external object based on the received light.

[0174] According to the present disclosure, the display driving circuit can perform first MURA compensation on input data based on a reference look-up table, and can perform second MURA compensation based on a supplementary compensation value corresponding to the gray level period of the input data. In this way, MURA that is not removed in the first MURA compensation performed separately using the reference look-up table can be additionally removed. Therefore, there are provided a display driving circuit configured to provide an image with improved quality, an operation method of the display driving circuit, and an operation method of an optical-based MURA inspection device configured to extract information for removing MURA of a display panel.

[0175] As is traditional in the art, embodiments may be described and illustrated in terms of blocks that perform one or more of the described functions. These blocks, which may be referred to herein as units or modules, etc., are physically implemented by analog and / or digital circuitry such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hardwired circuitry, etc., and may optionally be driven by firmware and / or software. For example, the circuitry may be embodied in one or more semiconductor chips or embodied on a substrate support such as a printed circuit board. The circuitry constituting the blocks may be implemented by dedicated hardware, or by a processor (e.g., one or more programmed microprocessors and associated circuitry), or by a combination of dedicated hardware that performs some of the functions of the block and a processor that performs other functions of the block. Each block of an embodiment may be physically divided into two or more interacting and discrete blocks without departing from the scope of the present disclosure. Similarly, the blocks of an embodiment may be physically combined into more complex blocks without departing from the scope of the present disclosure. Aspects of an embodiment may be implemented by instructions stored on a non-transitory storage medium and executed by a processor.

[0176] Although the present disclosure has been described with reference to exemplary embodiments thereof, it will be apparent to those of ordinary skill in the art that various changes and modifications can be made thereto without departing from the spirit and scope of the present disclosure as set forth in the appended claims.

Claims

1. A method of operating a display driving circuit, the display driving circuit being configured to drive a display panel, the method comprises: Receiving input data from an external device; Determining a gray level period corresponding to the input data among a plurality of gray level periods based on a plurality of thresholds; Calculating a final compensation value based on the determined gray level period and a reference look-up table generated according to a reference gray level; Performing MURA compensation on the input data based on the final compensation value to generate final data; and Controlling the display panel based on the final data, wherein calculating the final compensation value includes: Determining a coefficient corresponding to the determined gray level period; Calculating the distance between the gray level of the input data and the reference gray level; and Calculating the final compensation value based on the coefficient, the distance, and the reference look-up table.

2. The method according to claim 1, wherein The reference look-up table includes reference compensation values of a plurality of pixels of the display panel with respect to the reference gray level.

3. The method according to claim 1, wherein The plurality of gray level periods are divided based on the plurality of thresholds.

4. The method according to claim 3, wherein The plurality of thresholds are determined in advance based on data that is MURA compensated based on the reference look-up table.

5. The method according to claim 1, wherein When the determined gray level period is a first gray level period, the final compensation value corresponds to a first value, When the determined gray level period is a second gray level period different from the first gray level period, the final compensation value corresponds to a second value, and The absolute value of the first value is different from the absolute value of the second value.

6. The method according to claim 1, wherein When the determined gray level period is a gray level period including the reference gray level, the final compensation value is equal to the reference compensation value included in the reference look-up table.

7. The method according to claim 1, wherein During an inspection process of the display driving circuit and the display panel, information about the reference look-up table and the plurality of thresholds is stored in a storage circuit of the display driving circuit.

8. The method according to claim 7, further comprises: During the inspection process, after the reference look-up table is stored in the storage circuit, in response to a gray level pattern from an optically based MURA inspection device, performing MURA compensation on pattern data corresponding to the gray level pattern based on the reference look-up table to generate first compensated pattern data; and During the inspection process, controlling the display panel based on the first compensated pattern data.

9. A display driving circuit, the display driving circuit being configured to drive a display panel, the display driving circuit comprises: A storage circuit configured to store a plurality of thresholds and a reference look-up table generated based on a reference gray level; A MURA compensation circuit configured to receive input data from an external device, determine a gray level period corresponding to the input data among a plurality of gray level periods based on the plurality of thresholds, calculate a final compensation value based on the determined gray level period and the reference look-up table, and perform MURA compensation on the input data based on the final compensation value to generate final data; A source driver configured to drive a plurality of source lines connected to the display panel; And A timing controller configured to control the source driver based on the final data, wherein the MURA compensation circuit includes: A final compensation value calculation module configured to determine the gray level period corresponding to the input data based on the plurality of thresholds, and calculate the final compensation value based on the determined gray level period and the reference look-up table, wherein the final compensation value calculation module includes: A distance determiner configured to determine the distance between the input data and the reference gray level; A period determiner configured to determine a coefficient corresponding to the gray level period corresponding to the input data; A supplementary compensation value calculator configured to calculate a supplementary compensation value based on the coefficient, the distance, and the reference look-up table; and A final compensation value calculator configured to combine the supplementary compensation value and the information of the reference look-up table to calculate the final compensation value.

10. The display driving circuit according to claim 9, wherein, During the inspection process of the display driving circuit, the reference look-up table and the plurality of thresholds are stored by an optical-based MURA inspection device.

11. The display driving circuit according to claim 9, wherein, The plurality of gray level periods are divided based on the plurality of thresholds.

12. The display driving circuit according to claim 9, wherein, The MURA compensation circuit further includes: A compensation module configured to perform the MURA compensation on the input data based on the final compensation value to generate the final data.

13. The display driving circuit according to claim 12, further including: A gamma correction circuit configured to generate a gamma reference voltage based on a gamma value, wherein The source driver is further configured to control the plurality of source lines based on the gamma reference voltage under the control of the timing controller.

14. An operation method of an optical-based MURA inspection device configured to extract information for compensating MURA of a display panel, the method includes: Measuring reference optical information from the display panel, the display panel being controlled based on a reference gray level; Generating a reference look-up table based on the reference optical information; Storing the reference look-up table in a display driving circuit configured to control the display panel; Generating a gray level pattern based on a plurality of gray levels that can be exhibited by the display panel; Measuring supplementary optical information from the display panel, the display panel being controlled based on the gray level pattern; Determine a plurality of thresholds for determining a plurality of gray level periods based on the gray level pattern and the supplementary optical information; and store the plurality of thresholds in the display driving circuit, wherein the display panel is controlled based on first compensation pattern data, and the first compensation pattern data is generated by performing MURA compensation on pattern data corresponding to at least one gray level among the plurality of gray levels based on the reference look-up table.

15. The method according to claim 14, wherein determining the plurality of thresholds for determining the plurality of gray level periods based on the gray level pattern and the supplementary optical information includes: detecting a luminance difference after the MURA compensation based on the supplementary optical information for the at least one gray level; dividing the plurality of gray levels into the plurality of gray level periods based on the absolute value of the luminance difference, the polarity of the luminance difference, and the distance between the supplementary optical information and the reference gray level; and determining the plurality of thresholds based on the plurality of gray level periods.

16. The method according to claim 15, further comprising: calculating a coefficient corresponding to each of the plurality of gray level periods based on the supplementary optical information; and storing the coefficient in the display driving circuit.

17. The method according to claim 15, further comprising: storing the reference look-up table or the plurality of thresholds in another display driving circuit configured to control a display panel different from the display panel.

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