Luminance compensation system and display device

Abstract

Disclosed in an embodiment is a luminance compensation system comprising: an image acquisition unit for acquiring a first image on a display panel in which a plurality of sub-pixels are connected to one data line for each horizontal line; and a first compensation gain generation unit for generating a first compensation gain for each block by comparing a luminance value for each block of the first image with a preset target luminance value, wherein the first compensation gain compensates for a luminance deviation according to the difference between states of charge of the plurality of sub-pixels.

Description

Luminance compensation system and display device

[0001] The embodiment relates to a compensation system that calculates a compensation value that compensates for a luminance deviation of a display panel and a display device in which the compensation value is stored.

[0002] Liquid crystal displays (LCDs) using an active matrix drive system use thin film transistors (TFTs) as switching elements to display images. Because LCDs can be miniaturized, they are used not only as displays in portable information devices, office equipment, and computers, but also in a variety of other applications, including televisions.

[0003] In order to reduce the circuit cost of liquid crystal displays, a panel structure (hereinafter referred to as a "Double Rate Driving (DRD) panel") is being applied in which adjacent thin film transistors (TFTs) on the same display line are connected to the same data line to reduce the number of data lines and the number of output channels of the data driving circuit.

[0004] However, the DRD panel has a problem in that the sub-pixels connected to the same data voltage line have different amounts of data voltage charge, resulting in uneven brightness.

[0005] The embodiment provides a display device in which the luminance deviation of sub-pixels is improved.

[0006] The embodiment may provide a compensation system capable of calculating block-by-block compensation gains of a panel in real time prior to shipment.

[0007] The tasks of the present invention are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by those skilled in the art from the description below.

[0008] A luminance compensation system according to one feature of the present invention comprises: an image acquisition unit for acquiring a first video image of a display panel in which a plurality of sub-pixels are connected to one data line for each horizontal line; and a first compensation gain generation unit for generating a first compensation gain for each block by comparing a luminance value for each block of the first video image with a preset target luminance value, wherein the first compensation gain compensates for a luminance deviation according to a difference in the charging amounts of the plurality of sub-pixels.

[0009] A brightness compensation system according to one feature of the present invention includes an image acquisition unit that acquires a first video image of a display panel and a second video image of a different color from the first video image; a first compensation gain generation unit that compares a block-by-block brightness value of the first video image with a preset first target brightness value to generate a first compensation gain for each block; and a second compensation gain generation unit that compares a block-by-block brightness value of the second video image with a preset target brightness value to generate a second compensation gain for each block.

[0010] According to one aspect of the present invention, a display device comprises: a display panel; a data driving unit that applies a data voltage to the display panel; a memory that stores a compensation value according to a charge amount deviation for each of a plurality of blocks of the display panel; and a data conversion unit that receives image data and the compensation value and generates correction data by applying the compensation value to the image data for each of the blocks, wherein the display panel has a plurality of sub-pixels connected to one data line for each horizontal line, and the compensation value compensates for a brightness deviation according to a charge amount difference of the plurality of sub-pixels.

[0011] According to an embodiment, luminance unevenness due to charge amount deviation of data voltage can be improved.

[0012] The embodiment can calculate the block-by-block compensation gain of the panel in real time before shipment.

[0013] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

[0014] FIG. 1 is a drawing showing a compensation system of a display panel according to one embodiment of the present invention.

[0015] FIG. 2 is a drawing showing a pixel structure of a display panel according to one embodiment of the present invention.

[0016] FIG. 3 is a drawing showing a pixel driving sequence of a display panel according to one embodiment of the present invention.

[0017] FIG. 4 is a voltage waveform diagram applied to a third data line to drive a blue sub-pixel in a display panel according to one embodiment of the present invention.

[0018] FIG. 5 is a drawing showing a blue sub-pixel of a display panel emitting light according to one embodiment of the present invention.

[0019] FIG. 6 is a voltage waveform diagram applied to a third data line and a fourth data line to drive a green sub-pixel in a display panel according to one embodiment of the present invention.

[0020] FIG. 7 is a drawing showing a green sub-pixel of a display panel emitting light according to one embodiment of the present invention.

[0021] FIG. 8 is a drawing showing a red sub-pixel of a display panel emitting light according to one embodiment of the present invention.

[0022] Figure 9 is a block diagram of a brightness compensation system according to one embodiment of the present invention.

[0023] FIG. 10 is a graph showing a method for generating a compensation gain of a display panel according to one embodiment of the present invention.

[0024] FIG. 11 is a flowchart showing a process for generating a compensation gain of a display panel according to one embodiment of the present invention.

[0025] FIG. 12 is a flowchart showing a process for generating a compensation gain of a display panel according to another embodiment of the present invention.

[0026] Figure 13 is a diagram showing the luminance of the first video image before the Mura compensation gain is applied.

[0027] Fig. 14 is a diagram showing the luminance of the first video image after the Mura compensation gain is applied.

[0028] Figure 15 is a block diagram of a display device according to one embodiment of the present invention.

[0029] The advantages and features of the present invention, and the methods for achieving them, will become clearer with reference to the embodiments described in detail below together with the accompanying drawings. The present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms. The embodiments are provided solely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined solely by the scope of the claims.

[0030] The shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings for explaining embodiments of the present invention are illustrative, and the present invention is not limited to the details depicted in the drawings. Throughout the specification, the same reference numerals designate substantially the same components. Furthermore, in describing the present invention, detailed descriptions of related known technologies will be omitted if they are deemed to unnecessarily obscure the gist of the present invention.

[0031] The following embodiments can be partially or fully combined or combined with one another, enabling various technically diverse interconnections and operations. Each embodiment can be implemented independently of the other, or can be implemented together in a related manner.

[0032] Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings.

[0033] FIG. 1 is a drawing showing a brightness compensation system of a display panel according to one embodiment of the present invention.

[0034] Referring to FIG. 1, a luminance compensation system according to an embodiment may include an image supply device (400), a photographing device (300), and a compensation module (200).

[0035] The luminance compensation system can display a test image on a display panel (140) using a test image signal and capture the test image displayed on the display panel using a capturing device (300). The capturing device (300) may be a camera, but is not limited thereto as long as it is a device capable of acquiring an image.

[0036] An image displayed on a display panel (140) by a test image signal can be defined as a test image, and an image captured by the test image can be defined as a video image.

[0037] The compensation module (200) can divide a captured video image into appropriate sizes, detect the luminance of each of a plurality of blocks into which the first video image (IMG1) is divided, and generate a detection luminance value for each block.

[0038] The compensation module (200) can generate a result of comparing the detected luminance value with a preset target luminance value for each block. The compensation module (200) can use the comparison result to determine the luminance deviation caused by pre-charge.

[0039] Pre-charge can refer to a state where the data voltage from the previous subpixel has been charged, increasing the voltage of the data line. Therefore, if pre-charge is present, the subpixel can be quickly charged to the target data voltage level.

[0040] Conversely, without pre-charge, the data voltage must be charged from a low voltage level, which may not fully reach the target level within a short period of time. Consequently, data voltage charge variations may occur between subpixels.

[0041] The compensation module (200) can generate a compensation value for a block in which luminance unevenness occurs using the comparison value generated as a comparison result. The compensation value may be a value for compensating for the driving voltage to be provided to a sub-pixel with pre-charge in the display panel.

[0042] The luminance compensation system according to the embodiment can store the generated compensation value in the memory (150) of the display panel. In the drawing, a state in which a data driving circuit (121) and a timing controller (110) are connected to the display panel (140) in the inspection step is illustrated, but the present invention is not limited thereto. The display panel (140) can be inspected without the data driving circuit (121) and the timing controller (110) being connected.

[0043] The luminance compensation system can store the generated compensation values ​​in a lookup table format. Thereafter, the stored compensation values ​​in the lookup table format can be stored in a memory (150) arranged on the first circuit board (161) of the display panel (140).

[0044] FIG. 2 is a diagram showing a pixel structure of a display panel according to an embodiment of the present invention. FIG. 3 is a diagram showing a pixel driving order of a display panel according to an embodiment of the present invention. FIG. 4 is a voltage waveform diagram applied to a third data line to drive a blue sub-pixel in a display panel according to an embodiment of the present invention. FIG. 5 is a voltage waveform diagram applied to a third data line and a fourth data line to drive a green sub-pixel in a display panel according to an embodiment of the present invention.

[0045] Referring to FIG. 2, the display panel (140) may have a plurality of sub-pixels (SP1, SP2, SP3) arranged between a plurality of data lines (Data1 to Data7) and a plurality of gate lines (Gate1 to Gate8). The plurality of sub-pixels (SP1, SP2, SP3) may include a red sub-pixel (SP1), a green sub-pixel (SP2), and a blue sub-pixel (SP3). However, the present embodiment is not limited thereto. For example, the plurality of sub-pixels (SP1, SP2, SP3) may further include a white sub-pixel.

[0046] Multiple data lines (Data1 to Data7) can be implemented using dot inversion, with polarities different from those of adjacent data lines. To reduce power consumption and prevent flickering, data voltages with different polarities can be applied to each row.

[0047] Multiple sub-pixels may be arranged on each data line for each horizontal line. For example, the third data line (Date3) may be connected to a blue sub-pixel (SP3) and a green sub-pixel (SP2) on the first horizontal line (HL1).

[0048] The third data line (Date3) can be connected to the red subpixel (SP1) and the blue subpixel (SP3) in the second horizontal line (HL2).

[0049] The third data line (Date3) can be connected to the green subpixel (SP2) and the blue subpixel (SP3) in the third horizontal line (HL3).

[0050] The third data line (Date3) can be connected to the red subpixel (SP1) and the blue subpixel (SP3) in the fourth horizontal line (HL4).

[0051] The red subpixel (SP1), green subpixel (SP2), and blue subpixel (SP3) can be arranged in sequence in the horizontal direction. Accordingly, subpixels of the same color can be arranged in the vertical direction.

[0052] In this way, two sub-pixels can be connected to a single data line. This structure can be defined as a DRD (Double Rate Driving) structure. However, the present embodiments are not limited to this. The above-described sub-pixel arrangement structure is exemplary, and various DRD structures can be applied. In addition, a TRD structure in which three sub-pixels are connected to a data line can also be connected.

[0053] The gate lines can be connected to each sub-pixel with two gate lines per horizontal line. In the DRD structure, since two sub-pixels are connected to one data line, the two sub-pixels can be driven independently by dividing and applying the gate signal. For example, when a gate high signal is applied to the first gate line (Gate1) while voltage is applied to the third data line (Data3), the blue sub-pixel (SP3) of the first horizontal line can be turned on, and when a gate high signal is applied to the second gate line (Gate2), the green sub-pixel (SP2) of the first horizontal line can be turned on.

[0054] Referring to FIGS. 3 and 4, the sub-pixels connected to the third data line (Date3) can be driven in the following order: a blue sub-pixel (1) of the first horizontal line (HL1), a green sub-pixel (2) of the first horizontal line (HL1), a red sub-pixel (3) of the second horizontal line (HL2), a blue sub-pixel (4) of the second horizontal line (HL2), a blue sub-pixel (5) of the third horizontal line (HL3), a green sub-pixel (6) of the third horizontal line (HL3), a red sub-pixel (7) of the fourth horizontal line (HL4), and a blue sub-pixel (8) of the fourth horizontal line (HL4).

[0055] When only the blue sub-pixel (SP3) is driven, a gate high signal may be applied to the first gate line (Gate1), the fourth gate line (Gate4), the fifth gate line (Gate5), and the eighth gate line (Gate8) connected to the blue sub-pixel (SP3), and a gate low signal may be applied to the gate lines connected to the remaining sub-pixels.

[0056] Referring to FIGS. 3 and 4, when a 127-level voltage is applied, the data voltage can be applied only to the blue subpixel (SP3). At this time, the blue subpixel (4) of the second horizontal line (HL2) may not be fully charged to the 127-level voltage because the data voltage of the previous green subpixel (3) is 0, so there is no pre-charge. The case where the data voltage is not fully charged can be defined as weak charging. In contrast, the blue subpixel (5) of the third horizontal line (HL3) can be quickly charged to the 127-level voltage because the data voltage was previously charged in the blue subpixel (4) of the second horizontal line (HL2). This can be defined as strong charging. In other words, the presence of a pre-charge can be defined as a case where the data voltage is previously charged in the previous subpixel.

[0057] Accordingly, a difference in brightness may occur because the blue sub-pixel (4) of the second horizontal line (HL2) and the blue sub-pixel (5) of the third sub-pixel have a difference in the amount of data voltage charged depending on whether pre-charge is present.

[0058] Referring to Fig. 5, a blue sub-pixel (SP32) with high brightness and a blue sub-pixel (SP31) with low brightness can be identified on the blue video image. This brightness difference may be caused by the presence or absence of pre-charge.

[0059] Fig. 6 is a voltage waveform diagram applied to the third data line (Date3) and the fourth data line (Date4) to drive the green sub-pixel (SP2) in the display panel (140) according to one embodiment of the present invention. Fig. 7 is a diagram showing the green sub-pixel (SP2) of the display panel (140) emitting light according to one embodiment of the present invention. Fig. 8 is a diagram showing the red sub-pixel (SP1) of the display panel (140) emitting light according to one embodiment of the present invention.

[0060] Referring to FIG. 6, it can be seen that for the green sub-pixels (SP2) connected to the third data line (Date3) and the fourth data line (Date4), there is no continuous sub-pixel charging section in each horizontal line. Therefore, since all green sub-pixels (SP2) are in a weakly charged state, the brightness can be relatively uniform.

[0061] Referring to Fig. 7, it can be seen that the green sub-pixel (SP2) is output with an overall dark luminance, but there is no charging deviation of the data voltage depending on the presence or absence of pre-charge.

[0062] Referring to Fig. 8, it can be seen that the red sub-pixel (SP1) is output with an overall dark luminance, similar to the green sub-pixel (SP2), but there is no charging deviation of the data voltage depending on whether pre-charge is present.

[0063] Fig. 9 is a block diagram of a luminance compensation system according to one embodiment of the present invention. Fig. 10 is a graph illustrating a method for generating a compensation gain of a display panel according to one embodiment of the present invention.

[0064] Referring to FIG. 9, a compensation system according to an embodiment may include an image supply device (400), a photographing device (300), and a compensation module (200).

[0065] The image supply device (400) can provide a test image to the display panel (140). The test image can be a color-coded image. For example, the image supply device (400) can supply a signal to turn on only blue or green sub-pixels among the sub-pixels of the display panel (140). Alternatively, the image supply device (400) can turn on sub-pixels of different colors among the sub-pixels of the display panel (140) to supply a mixed-color image.

[0066] The image supply device (400) can apply an overdriving value to the display panel (140) when supplying a test image to the display panel (140). The overdriving value can be applied to each horizontal line of the display panel. Therefore, the luminance deviation between horizontal lines of the display panel can be reduced. Accordingly, in the first image (IMG1) to which overdriving is applied, the luminance change (LA2) due to pre-charge can be clearly observed compared to the original image (OIG). In the case of an image to which overdriving is not applied, the luminance deviation (LA1) between horizontal lines may be so large that it may be difficult to accurately calculate a gain to compensate for pre-charge.

[0067] The image supply device (400) can store multiple levels of overdriving values ​​in advance. Accordingly, the image supply device (400) can select the most appropriate overdriving value capable of adjusting the brightness deviation in the display panel (140) and supply it for each line. The method for selecting the most appropriate overdriving value is not particularly limited. An overdriving value suitable for the panel can be selected through image analysis or output signal analysis, etc. Alternatively, an operator can determine an appropriate overdriving value by directly checking it with the naked eye.

[0068] The compensation module (200) may include an image acquisition unit (210) that acquires a first video image (IMG1) of the display panel (140), and a first compensation gain generation unit (220) that generates a block-by-block pre-charge compensation gain (first compensation gain).

[0069] The image acquisition unit (210) can acquire a video image captured by the photographing device (300). As described above, the video image may be an image to which overdriving has been applied. The video image may be an image in which a luminance deviation occurs due to pre-charge. For example, the video image may be an image in which a luminance deviation occurs due to pre-charge, but is not limited thereto. For example, the video image may be a blue video image or a mixed image of green and red.

[0070] The image acquisition unit (210) can acquire a first image (IMG1) by removing an image portion other than the display panel (140). To this end, the image acquisition unit (210) can rotate or perform distortion correction on the captured image.

[0071] The first compensation gain generation unit (220) may include a block generation unit (221) that divides the first video image (IMG1) into a plurality of regions, a luminance ratio calculation unit (222) that compares luminance values ​​for each block, a compensation gain generation unit (223) that selects a pre-charge compensation gain according to the luminance ratio, and a lookup table generation unit (224) that stores the compensation gain in the form of a lookup table.

[0072] The block generation unit (221) can generate multiple blocks by dividing the image so as to be able to segment the luminance unevenness area due to pre-charge in the first video image (IMG1). The number of blocks can be adjusted according to the size and number of areas where luminance deviation occurs. The block generation unit (221) can adjust the area and number of blocks so that luminance deviation areas of different levels can be segmented.

[0073] According to the embodiment, since images are captured with overdriving applied to each display panel (140), images with relatively reduced luminance deviation can be obtained. Accordingly, the number of blocks can be reduced, thereby reducing the capacity required to store compensation gains for each block in memory.

[0074] The block generation unit (221) can detect the luminance of each of a plurality of blocks and generate a detection luminance value for each block. The configuration for sensing luminance for each block can be applied to various luminance detection configurations without limitation.

[0075] The luminance ratio calculation unit (222) can generate a comparison result by comparing the detected luminance value of a block with a preset target luminance value. The target luminance value may be the luminance value of the brightest area, but the present embodiments are not limited thereto. For example, the target luminance value may be the average luminance value of multiple blocks, or the luminance value of an area in the center of the panel.

[0076] The brightness ratio calculation unit (222) can use the comparison results to determine whether there is a difference in the charging amount and the degree of the difference for each block depending on the presence or absence of pre-charge.

[0077] The ratio according to the charge amount deviation can be calculated by dividing the target luminance value (Target Value) by the block luminance value (Block Value) as in the following relational expression 1 to calculate the luminance ratio of each block. In relational expression 1, x and y are the coordinate values ​​of the block.

[0078] [Relationship 1]

[0079]

[0080] The compensation gain generation unit (223) can generate a compensation gain matching the luminance ratio calculated for each block. For example, a gain value can be matched to a representative luminance ratio range among the luminance ratios of multiple blocks.

[0081] Referring to Fig. 10, the gain values ​​(gain1 to gain4) corresponding to the luminance ratio of the image data can be obtained by piece-wise interpolation using linear equations for each representative luminance ratio (Ratio1 to Ratio4). For example, if the calculated luminance ratio corresponds to Ratio 3, it can be converted to a gain value corresponding to gain 3. However, the method of mapping the luminance ratio and gain value is not limited to this, and various mapping methods can be applied.

[0082] The lookup table generation unit (224) can generate and store a lookup table including the generated compensation gain. The lookup table information stored in the compensation module (200) can be stored in the memory (150) of the panel.

[0083] According to an embodiment, a camera can be used to acquire video images while the panels are continuously moving during shipment, and a pre-charge compensation gain can be generated for each block of each panel in real time. Therefore, even when inspecting multiple panels, there is an advantage in that the pre-charge compensation gain can be automatically calculated for each block.

[0084] The compensation module (200) according to the embodiment may further include a second compensation gain generation unit (230).

[0085] The second compensation gain generation unit (230) may include a block generation unit (231) that generates brightness for each block and a group compensation gain generation unit (232).

[0086] The block generation unit (231) can divide the second video image (IMG2) into a plurality of blocks and generate a luminance value of each divided area. The second video image (IMG2) may be an image with a different color from the first video image (IMG1).

[0087] The first video image (IMG1) may be a video image in which a luminance deviation occurs due to pre-charge, and the second video image (IMG2) may be a video image in which a luminance deviation does not occur due to pre-charge.

[0088] For example, the first video image (IMG1) may be a blue video image, and the second video image (IMG2) may be a green or red video image. However, the present embodiments are not limited thereto.

[0089] The second video image may exhibit brightness variation due to pre-charge, but not due to mura. Subpixels positioned close to the data-driven circuitry in the display panel enjoy smooth power supply and therefore exhibit high brightness, while subpixels positioned farther from the data-driven circuitry may experience relatively poor power supply and exhibit relatively low brightness. A variety of other causes can also contribute to brightness variation.

[0090] The Mura compensation gain generation unit (232) can generate a result of comparing the detected luminance value for each block with a preset target luminance value. The target luminance value may be, but is not limited to, the average luminance value of multiple segmented areas. For example, the target luminance value may be the luminance value of the brightest area.

[0091] The Mura compensation gain generation unit (232) can calculate each block dim gain by dividing the target luminance value by the block luminance value as in the following relational expression 2.

[0092] [Relationship 2]

[0093]

[0094] The compensation module (200) can compensate for the generated mura compensation gain (second compensation gain) by applying the mura compensation gain to the first image (IMG1). Accordingly, the first image (IMG1) can eliminate the luminance deviation due to mura in addition to the luminance deviation due to pre-charge.

[0095] The first compensation gain generation unit (220) can generate a pre-charge compensation gain using the first image (IMG1) from which the luminance deviation due to mura has been removed. According to an embodiment, by removing the luminance deviation due to mura in advance before generating the pre-charge compensation gain, only the luminance deviation due to pre-charge can be accurately calculated.

[0096] FIG. 11 is a flowchart showing a process for generating a compensation gain of a display panel according to one embodiment of the present invention.

[0097] Referring to FIG. 11, a method for calculating a compensation value of a display panel (140) may include a step of receiving a first video image (IMG1) of a DRD panel (S11), a step of dividing the first video image (IMG1) and calculating a luminance value for each divided area (S12), a step of comparing the luminance of each divided area with a target luminance (S13), a step of calculating a pre-charge compensation gain of each divided area (S14), and a step of storing the pre-charge compensation gain of each divided area in a memory (150) (S15).

[0098] The step (S11) of receiving the first video image (IMG1) of the DRD panel can display a test image on the panel by a test video signal and capture the test image displayed on the panel using a camera.

[0099] In an embodiment, the test image may be a blue image with a luminance deviation due to pre-charge. However, the present embodiments are not limited thereto. If a pre-charge difference occurs in a color image other than a blue image, the image of that image may also be captured, depending on the DRD connection structure.

[0100] The first video image (IMG1) may be a test image with pre-applied overdriving. Overdriving involves providing a source signal at a higher level than the display data to the pixels. The data in the test image may be compensated for by overdriving, and the source signal may be provided to the pixels at a higher level in response to the compensated display data. The overdriving value may be applied differently for each horizontal line.

[0101] The step (S12) of dividing the first video image (IMG1) and calculating the luminance value for each divided area can divide the image into areas of an appropriate size and number that can demarcate the luminance uneven area due to pre-charge in the first video image (IMG1). Thereafter, the luminance of each of the divided plurality of blocks can be detected, and a detected luminance value for each block can be generated.

[0102] The step (S13) of comparing the luminance of each segmented area with the target luminance can generate a comparison result by comparing the detected luminance value with the preset target luminance value (Target Luminance) for each block. Thereafter, using the comparison result, the occurrence and degree of charge amount deviation depending on the presence or absence of pre-charge can be determined for each block.

[0103] Step (S14) of calculating the pre-charge compensation gain for each partition area can calculate the gain based on the ratio of the partition area's luminance to the target luminance for each block. A gain value corresponding to the luminance ratio of the image data can be obtained through piece-wise interpolation. However, the method of mapping the luminance ratio and gain value is not limited to this, and various methods can be applied.

[0104] The step (S15) of storing the pre-charge compensation gain of each partition area in the memory (150) may store the calculated pre-charge compensation gain for each block in the form of a lookup table. According to an embodiment, when inspecting a display panel, a camera may be used to generate and store the pre-charge compensation gain for each block of each display panel in real time.

[0105] Fig. 12 is a flowchart illustrating a process for generating a compensation gain of a display panel according to another embodiment of the present invention. Fig. 13 is a diagram illustrating the luminance of a first video image before applying the mura compensation gain. Fig. 14 is a diagram illustrating the luminance of a first video image after applying the mura compensation gain.

[0106] Referring to FIG. 12, a compensation method according to an embodiment may include a step of receiving a first video image (IMG1) and a second video image (IMG2) (S21), a step of dividing the first video image (IMG1) and calculating a luminance value for each divided area (S22), a step of calculating a mura compensation gain using the second video image (IMG2) and applying the mura compensation gain to the luminance value of the first video image (IMG1) (S23), a step of comparing the luminance of each divided area with a target luminance (S24), a step of calculating a pre-charge compensation gain of each divided area (S25), and a step of storing the pre-charge compensation gain of each divided area in a memory (150) (S26).

[0107] The step (S21) of receiving a first video image (IMG1) and a second video image (IMG2) may be performed by acquiring the first video image (IMG1) using a camera and then acquiring the second video image (IMG2). The second video image (IMG2) may be an image having a different color from the first video image (IMG1).

[0108] For example, the first video image (IMG1) may be a video image in which luminance unevenness occurs due to pre-charge, and the second video image (IMG2) may be a video image in which luminance unevenness does not occur due to pre-charge. However, the present embodiments are not limited thereto.

[0109] For example, the first video image (IMG1) may be a blue video image, and the second video image (IMG2) may be a green video image.

[0110] For example, the first video image (IMG1) may be a video image in which luminance unevenness occurs due to a specific cause, and the second video image (IMG2) may be a video image in which luminance unevenness does not occur due to a specific cause. The characteristic cause may be a concept that includes both deviations due to the presence or absence of pre-charge and deviations due to other reasons.

[0111] The step (S22) of dividing the first video image (IMG1) and calculating the luminance value for each divided area can divide the image into areas of an appropriate size and number that can demarcate the luminance non-uniform area due to pre-charge in the first video image (IMG1). Thereafter, the luminance of each of the divided plurality of blocks can be detected, and a detected luminance value for each block can be generated.

[0112] The step (S23) of calculating a gain for mura compensation using the second video image (IMG2) and applying it to the luminance value of the first video image (IMG1) can divide the second video image (IMG2) into areas of an appropriate size and number. Thereafter, the luminance of each of the divided blocks can be detected, and a detected luminance value for each block can be generated.

[0113] A plurality of data driving circuits (121) can be connected to the panel. Sub-pixels close to the data driving circuit (121) have sufficient power supply and thus have relatively bright brightness, while sub-pixels farther from the data driving circuit (121) have less smooth power supply and thus have relatively darker brightness. Accordingly, the area between the data driving circuits (121) becomes relatively dark, resulting in block dim.

[0114] Accordingly, a comparison result can be generated by comparing the detected luminance value and the preset target luminance value for each block. The target luminance value may be, but is not limited to, the average value of the luminance of multiple divided areas. For example, the target luminance value may be the luminance value of the brightest area. The compensation module (200) can divide the detected luminance value and the target luminance value for each block to calculate the mura compensation gain for each block. At this time, the mura gain matching the luminance ratio of the image data can be calculated using a piece-wise interpolation method.

[0115] Referring to Fig. 13, the valley portion (P1) in the luminance distribution of the first video image before applying the mura compensation gain is the portion where the luminance difference occurs due to mura. However, after applying the mura compensation gain, it can be seen that the valley portion has been compensated for to a significant extent, as shown in Fig. 14. In Figs. 13 and 14, the X-axis represents the number of pixels arranged in the horizontal direction, and the Y-axis represents the pixel luminance value (Pixel Value).

[0116] According to an embodiment, before applying the pre-charge compensation gain using the first video image (IMG1), pre-compensation can be performed to multiply the mura compensation gain. This eliminates the luminance unevenness caused by mura, thereby providing the advantage of accurately determining only the luminance unevenness caused by pre-charge. The following steps can be applied as described in FIG. 11.

[0117] Figure 15 is a block diagram of a display device according to one embodiment of the present invention.

[0118] Referring to FIG. 15, a display device (100) according to an embodiment of the present invention performs a display function and may be implemented as a flat panel display device (100) such as a liquid crystal display (LCD) device or an organic light emitting diode (OLED) device. In the embodiment, a liquid crystal display is described.

[0119] The display device (100) includes a display panel (140), a data driver (120), a gate driver (130), and a timing controller (110). The display panel (140) may have a DRD structure in which a plurality of sub-pixels are connected to one data line in one horizontal line as described in FIGS. 1 and 2.

[0120] The data driving unit (120) receives pixel data and a data control signal (DCS) from the timing controller (110). The data driving unit (120) can convert pixel data into a data voltage and supply it to the sub-pixel of the display panel (140).

[0121] The gate driver (130) receives a gate control signal (GCS) from the timing controller (110). The gate driver (130) supplies gate signals to a plurality of gate lines (GL) according to the gate control signal (GCS).

[0122] The timing controller (110) receives digital video data and timing signals from the host system (10).

[0123] The timing controller (110) may include a data input unit (111), a data conversion unit (113), and a data output unit (112).

[0124] The data input unit (111) receives digital video data from the host system (10) and can provide the input digital video data to the data conversion unit (113).

[0125] The data conversion unit (113) can determine a compensation value for each of a plurality of sub-pixels based on digital video data for each frame.

[0126] The data conversion unit (113) of the timing controller (110) can retrieve coordinate information of a sub-pixel in which a luminance deviation occurs due to pre-charge stored in a register (114). According to an embodiment, coordinate information of a sub-pixel in which a luminance deviation occurs due to pre-charge may be stored in advance in the register (114). For example, coordinate information of a sub-pixel in which a deviation occurs due to pre-charge for each implemented color may be stored in the register (114).

[0127] The data conversion unit (113) of the timing controller (110) can read the overdriving value and pre-charge compensation gain stored in the memory (150). The memory (150) may be placed on the first circuit board (161 in FIG. 1) on which the data driving circuit (121) is placed, rather than the second circuit board (162 in FIG. 1) on which the timing controller is placed. The overdriving value and pre-charge compensation gain may also be stored in a memory or register placed in the timing controller.

[0128] The data conversion unit (113) can adjust the gain differently for each sub-pixel arranged within a block, rather than adjusting the gain for each block area.

[0129] The data conversion unit (113) can calculate a compensation value by multiplying the overdriving value and the pre-charge compensation gain for each block. For example, if the overdriving value of the first block is 20 and the pre-charge compensation gain is 0.8, an overdriving value of 16 can be applied to the first block.

[0130] At this time, the data conversion unit (113) may not uniformly apply an overdriving value of 16 to all sub-pixels arranged within the first block, but may apply different compensation values ​​to sub-pixels with pre-charge and sub-pixels without pre-charge within the first block.

[0131] For example, a subpixel with pre-charge can have an overdriving value of 16 applied, and a subpixel with pre-charge can have an overdriving value of 22 applied without block compensation gain. In other words, the pre-charge compensation gain can only be applied to the subpixels with pre-charge. With this configuration, the luminance can be adjusted uniformly by applying the compensation value only to some subpixels with uneven luminance within the block.

[0132] Since the content of the specification described in the problem to be solved, the means for solving the problem, and the effect described above does not specify the essential features of the claim, the scope of the claim is not limited by the matters described in the content of the specification.

[0133] While the embodiments have been described in more detail with reference to the attached drawings, the present invention is not necessarily limited to these embodiments, and various modifications may be implemented without departing from the technical spirit of the present invention. Accordingly, the embodiments disclosed in the present invention are intended to illustrate, rather than limit, the technical spirit of the present invention, and the scope of the technical spirit of the present invention is not limited by these embodiments. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

Claims

1. An image acquisition unit for acquiring a first video image of a display panel in which a plurality of sub-pixels are connected to one data line for each horizontal line; and It includes a first compensation gain generation unit that compares the block-by-block luminance value of the first video image with a preset target luminance value to generate a first compensation gain for each block, A luminance compensation system in which the first compensation gain compensates for luminance deviation according to a difference in the amount of charge of the plurality of sub-pixels.

2. In paragraph 1, A luminance compensation system in which the image acquisition unit acquires a second image of a different color from the first image.

3. In paragraph 2, A luminance compensation system comprising a second compensation gain generation unit that compares the luminance value of each block of the second video image with a preset target luminance value to generate a second compensation gain for each block.

4. In paragraph 3, The above first video image is an image in which a pre-charge deviation occurs for each subpixel, A luminance compensation system in which the second video image is an image in which no pre-charge deviation occurs per subpixel.

5. In paragraph 3, The above first compensation gain generation unit, A block generation unit that divides the first video image to which the second compensation gain is applied and calculates a luminance value for each block; A luminance ratio calculation unit that compares the luminance value of each block with the target value; and A luminance compensation system comprising a compensation gain generation unit that calculates a first compensation gain for each block according to a ratio of the luminance value and the target value.

6. In paragraph 1, The above first video image is an image to which an overdriving value is applied, a luminance compensation system.

7. In paragraph 6, A luminance compensation system in which the size and number of blocks for dividing the first video image are determined according to the degree of luminance deviation that occurs depending on whether the first video image is pre-charged.

8. An image acquisition unit that acquires a first image of a display panel and a second image of a different color from the first image; A first compensation gain generation unit that generates a first compensation gain for each block by comparing the block-by-block luminance value of the first video image with a preset first target luminance value; and A luminance compensation system comprising a second compensation gain generation unit that compares the luminance value of each block of the second video image with a preset target luminance value to generate a second compensation gain for each block.

9. In paragraph 8, The above first compensation gain is a luminance compensation system that compensates for luminance deviation according to the difference in the charging amount of the subpixel.

10. Display panel; A data driving circuit that applies a data voltage to the above display panel; A memory storing a compensation value according to the charge amount deviation for each of the plurality of blocks of the above display panel; and A data conversion unit that receives image data and the compensation value and generates correction data by applying the compensation value to the image data for each block, The above display panel has multiple sub-pixels connected to one data line for each horizontal line, A display device in which the above compensation value compensates for a luminance deviation according to a difference in the amount of charge of the plurality of sub-pixels.

11. In paragraph 10, A first circuit board connected to the above data driving circuit; and A second circuit board is provided on which a timing controller including the above data conversion unit is arranged, A display device, wherein the above memory is arranged on the first circuit board.

12. In paragraph 10, The above data conversion unit Applying a modulation data signal to which the compensation value is applied to a sub-pixel in which a difference in charge amount occurs within the above block, A display device in which the compensation value is not applied to sub-pixels in which no difference in charge amount occurs within the above block.

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