Compensation information providing apparatus and method, and display driving apparatus using compensation information

Abstract

This disclosure discloses an apparatus and method for providing compensation information, specifically demura-compressed compensation information. It also discloses a display driving device for addressing defects in a screen using compressed compensation information. The apparatus for providing compensation information includes a compensation value providing unit configured to provide compensation values ​​for pixels and a compression unit configured to perform compression on the compensation values ​​for each block of the screen.

Description

Technical Field

[0001] This disclosure relates to apparatus and methods for providing compensation information, specifically demura-compressed compensation information. It also relates to a display driver device for addressing defects in a screen by using compressed compensation information. Background Technology

[0002] LCD or OLED panels are widely used as display panels.

[0003] Display panels may have defects such as mura due to reasons such as errors in the manufacturing process.

[0004] For example, mura refers to a defect in which a spot with irregular brightness appears on a specific pixel or area of ​​the screen displayed on the display panel.

[0005] Defects such as mura can increase with the size of the display panel and act as an important factor in determining the quality of the display panel.

[0006] Therefore, it is necessary to effectively compensate for defects such as mura in order to improve the quality of display panels.

[0007] Defects in the screen can be addressed by compensating for the brightness of the displayed data for each pixel.

[0008] The display panel can be configured to display a screen in response to a source signal provided by a display driver. The display driver is configured to receive display data and output a source signal corresponding to the display data.

[0009] The display driver can store compensation information for compensating the brightness of display data in order to resolve defects in the screen, and can provide a source signal capable of compensating for defects in the screen by compensating the brightness of display data for each pixel via the stored compensation information.

[0010] The amount of compensation information used to compensate for defects in the screen increases with the size of the display panel. As the amount of compensation information increases, the display driver device needs a large-capacity memory to store the compensation information.

[0011] Large-capacity memory can be detrimental to the design or production costs of display driver devices composed of ICs. Therefore, it is necessary to compress and compensate for information to reduce the required storage capacity.

[0012] When errors occur during the compression of compensation information, the efficiency of screen defect compensation may decrease. Block-based compression, which divides the screen into multiple blocks and compresses the compensation information, can be used to prevent the increase of errors.

[0013] However, block-based compression can typically suffer from block artifacts. If compensation information is compressed at a high compression ratio and large blocks are chosen for compression, artifacts may appear between blocks.

[0014] Therefore, in order to reduce errors and prevent artifacts during compression, compensation information needs to be compressed effectively in a way that is correlated between adjacent pixels or blocks. Summary of the Invention

[0015] Various implementations are intended to provide devices and methods for providing compensation information for demura, which can reduce the memory capacity required for storage by effectively compressing the compensation value for each pixel used to compensate for defects in the screen.

[0016] Furthermore, various implementations are intended to provide devices and methods for providing compensation information for demura, which can prevent artifacts between blocks divided for compression and can compress the compensation value of each pixel so that the compensation value is correlated between adjacent pixels or blocks.

[0017] Furthermore, various implementations are intended to provide a display driving device that uses compensation information to compensate for the brightness of each pixel by using the compensation information compressed as described above to resolve defects in the screen.

[0018] In an implementation, the device for providing compensation information for demura may include: a compensation value providing unit configured to provide compensation values ​​for pixels; and a compression unit configured to divide the screen into multiple blocks, generate a primary compression map and a representative value of the primary compression by performing primary compression on the compensation values ​​for each block, and generate a secondary compression map and a reference value of the secondary compression by performing secondary compression on the representative values ​​of the blocks.

[0019] Primary compression may include: extracting a representative value of the compensation value of the block, extracting the difference between the representative value and the compensation value, and generating a primary compressed map corresponding to the pixels of the block using the difference.

[0020] In addition, secondary compression may include: setting a reference value for the representative value, performing differential encoding on the representative value using the reference value, and generating a secondary compressed map corresponding to the block by using the encoded value generated as the result of differential encoding.

[0021] In another embodiment, the method for providing compensation information for demura may include: dividing the screen into multiple blocks; performing primary compression on the compensation values ​​of pixels in each block, and generating a primary compressed map and a representative value of the primary compression; and performing secondary compression on the representative values ​​of the blocks, and generating a secondary compressed map and a reference value of the secondary compression. Primary compression may include: extracting a representative value of the compensation values ​​for the block, extracting the difference between the representative value and the compensation value, and generating a primary compressed map corresponding to the pixels of the block using the difference. Secondary compression may include: setting a reference value for the representative value, performing differential encoding on the representative value using the reference value, and generating a secondary compressed map corresponding to the block using the encoded value generated as the result of differential encoding.

[0022] In another embodiment, the display driving device may include: a compensation information storage unit configured to store and provide a primary compressed map with differences, a secondary compressed map with encoded values, and a reference value; a compensation value generation unit configured to convert the encoded values ​​of the secondary compressed map into representative values ​​of multiple blocks into which the screen is divided using the reference value, convert the differences of the primary compressed map into compensation values ​​corresponding to pixels of the respective blocks using the representative values ​​of each block, and provide a compensation value for each pixel; and a defect compensation unit configured to receive display data and the compensation value for each pixel, compensate the display data using a compensation equation to which the compensation value has been applied to the coefficient values, and output the compensated display data.

[0023] The advantage of this disclosure is that it can effectively compress compensation values ​​through primary compression of blocks and secondary compression of representative values ​​of blocks, and can effectively reduce the memory capacity used to store compensation information for defects in the compensation screen.

[0024] Furthermore, the advantage of this disclosure is that it can address the increase in error caused by error propagation by performing compression on the representative value of the block and the compensation value of the block separately in block-based compression.

[0025] Furthermore, the advantage of this disclosure is that it can solve the block artifact problem that mainly occurs in block-based compression, since the compensation values ​​of pixels are compressed on a block-by-block basis.

[0026] Furthermore, the advantage of this disclosure is that by performing secondary compression using adjacent blocks that typically have similar values, this disclosure can have low or no loss, and thus can improve the compression ratio of the compensation information. Attached Figure Description

[0027] Figure 1 This is a block diagram illustrating a preferred embodiment of a device for providing compensation information for demura according to the present disclosure.

[0028] Figure 2 This is a flowchart illustrating a preferred embodiment of a method for providing compensation information for demura.

[0029] Figure 3 It is a diagram used to describe primary compression.

[0030] Figure 4 It is a detailed flowchart used to describe the initial compression.

[0031] Figure 5 This is a diagram used to describe the method for generating a primary compressed graph.

[0032] Figure 6 It is a detailed flowchart used to describe secondary compression.

[0033] Figure 7 This is a diagram describing a method for generating a primary compressed graph based on differential coding.

[0034] Figure 8 It is a diagram used to describe differential coding.

[0035] Figure 9 This is a block diagram illustrating the display system.

[0036] Figure 10 This is a detailed block diagram of a display driver device according to this disclosure. Detailed Implementation

[0037] This disclosure addresses defects in the screen of a display panel that are in the form of mura, which are spots. In the description of this disclosure, defects such as mura are defined as demura.

[0038] The defects in the screen need to be addressed in order to improve image quality.

[0039] Defects in the screen can be detected by Figure 1 The implementation of the device for providing compensation information is analyzed. The device for providing compensation information can generate, compress, and store correction information based on the analysis results.

[0040] refer to Figure 1 The device for providing compensation information can be shown as including an image receiving unit 10, a defect detection unit 20, a compensation value providing unit 30, a compression unit 40, and a compressed information storage unit 50.

[0041] Defect testing can be performed at multiple grayscale levels. Reference display data can be sequentially provided to a display panel (not shown) for each grayscale level. Exemplarily, the display panel can be driven to display a test screen based on reference display data provided to all pixels as the same grayscale level value. Furthermore, the display panel can sequentially display the test screen for each grayscale level.

[0042] For each grayscale level, the analysis of the test screen and the generation, compression, and storage of correction information are performed in the same manner, so redundant descriptions of them are omitted.

[0043] The image receiving unit 10 is configured to receive a test screen with a specific grayscale level from a display panel (not shown) and provide test display data corresponding to the test screen. The image receiving unit 10 can be configured to provide test data of the test screen obtained by measuring the brightness of each pixel using a method such as an image capture or a brightness measurement unit.

[0044] The defect detection unit 20 compares the test data with the previously stored reference data, detects the defect information of each pixel based on the comparison results, and provides the defect information.

[0045] It is understood that the reference data has a value corresponding to the normal brightness (i.e., the reference brightness) corresponding to the reference display data.

[0046] In the case of pixels with mura, for example, the test data for the corresponding pixel may have a value corresponding to a brightness that is lower or higher than the brightness of the reference data.

[0047] It can be understood that the defect detection unit 20 detects the defect information of each pixel, and the defect information corresponds to the difference between the brightness corresponding to the test data and the brightness corresponding to the reference data.

[0048] The compensation value providing unit 30 receives the defect information of each pixel and generates a coefficient value corresponding to the defect information of each pixel as a compensation value.

[0049] This disclosure can be used to illustrate the use of a compensation equation consisting of a quadratic expression to compensate for defects in the screen. In this case, it can be understood that the compensation equation is the same as Equation 1.

[0050] [Equation 1]

[0051] Y = aX 2 +bX+C

[0052] In Equation 1, Y is the brightness value of the pixel to be compensated for the defect. X is the normal brightness value of the pixel. That is, Y can be understood as the difference between the brightness value of the defective pixel and the normal brightness value of the pixel. Furthermore, the coefficients of the dimensions of the compensation equation are represented as a, b, and c, respectively.

[0053] The compensation value providing unit 30 generates coefficient values ​​a, b, and c for a compensation equation used to compensate for defects in the screen, and provides position information for each pixel along with the coefficient values. Hereinafter, the coefficient values ​​are described as compensation values.

[0054] The compensation value providing unit 30 can provide a compensation value for each coefficient. The compression unit 40, which will be described later, can perform compression for each coefficient. In embodiments of this disclosure, an example of the compression unit 40 operating relative to one coefficient is described. Coefficients can be compressed in the same manner, therefore redundant descriptions of them are omitted.

[0055] The compression unit 40 can receive the compensation value provided by the compensation value providing unit 30.

[0056] Compression unit 40 compresses the compensation value by dividing the screen into multiple blocks and performing truncation encoding based on the divided blocks before performing compression.

[0057] Compression unit 40 can compress the compensation value by sequentially performing primary compression and secondary compression. Compression unit 40 can generate a primary compression map and a representative value M for the block for primary compression by performing primary compression on the compensation value for each block, and can generate a secondary compression map and a reference value R for secondary compression by performing secondary compression on the representative value M of the block.

[0058] After performing primary and secondary compression sequentially, compression unit 40 can provide a primary compression map, a reference value R, and a secondary compression map, i.e., compensation information. In this case, it can be understood that each element in the primary compression map is a two-dimensional bitmap with a difference value of a preset number of bits. Similarly, it can be understood that the secondary compression map is a two-dimensional bitmap with an encoded value of a preset number of bits. For example, each of the difference value and the encoded value can be set to represent 3 bits, and the reference value R can be set to represent 12 bits.

[0059] The compression information storage unit 50 can store the primary compression map, the reference value R, and the secondary compression map (i.e., the compression result provided by the compression unit 40), and can provide the primary compression map, the reference value R, and the secondary compression map as compensation information to the display driver device, which will be described later, according to the manufacturer's intention.

[0060] refer to Figures 2 to 8 The compression of compression unit 40 described above will be described in more detail.

[0061] Compression unit 40 can perform, for example Figure 2 The primary and secondary compression are shown in the diagram.

[0062] The compression unit 40 constructs a compensation value corresponding to a screen provided by the compensation value providing unit 30 in the form of a two-dimensional table using the pixel position information (S20). That is, the compression unit 40 can construct a two-dimensional table by matching the compensation value with the pixel position information. The position information can be understood as the row and column positions of the pixels.

[0063] Subsequently, compression unit 40 divides the two-dimensional table into multiple blocks for block-based compression (S22). This can be understood as a screen being divided into multiple blocks. In this case, the blocks may have block location information, and the compensation values ​​included in the blocks may have pixel location information.

[0064] refer to Figure 3 For example, a two-dimensional table TA of compensation values ​​for a screen can be divided into four blocks: BA, BB, BC, and BD.

[0065] Compression unit 40 through the Figure 3 Each block in the process undergoes primary compression to generate a representative value M and a primary compressed graph for each block (S24). See later. Figures 3 to 5 Describes primary compression.

[0066] After performing primary compression, compression unit 40 generates a reference value R and a secondary compression map of the block by performing secondary compression on the representative value M of the block (S26). See later. Figures 6 to 8 Describes secondary compression.

[0067] Compression unit 40 can generate a primary compression map, a reference value R, and a secondary compression map by sequentially performing primary compression and secondary compression, and can store the primary compression map, the reference value R, and the secondary compression map in compression information storage unit 50 (S28).

[0068] refer to Figures 3 to 5 The primary compression of compression unit 40 described above is described.

[0069] exist Figure 3 In this process, compression unit 40 performs primary compression on each of the blocks BA, BB, BC, and BD divided from the two-dimensional table TA. For example... Figure 3 As shown, the primary compressed graph BAC and representative value M11 of block BA can be generated by primary compression of block BA. The primary compressed graph BBC and representative value M12 of block BB can be generated by primary compression of block BB. The primary compressed graph BCC and representative value M13 of block BC can be generated by primary compression of block BC. The primary compressed graph BDC and representative value M14 of block BD can be generated by primary compression of block BD.

[0070] Primary compression is performed on blocks BA, BB, BC, and BD in the same manner. Therefore, primary compression for a single block is described, and detailed descriptions of primary compression for each block are omitted.

[0071] refer to Figure 4 Describes the initial compression of a block. In Figure 4 In the description, the representative value of a block can be indicated as M. It can be understood that the representative value M corresponds to any one of the representative values ​​M11, M12, M13, and M14, depending on the block selected for primary compression.

[0072] Compression unit 40 extracts the representative value M (S40) of the block that has been selected for compression.

[0073] The compression unit 40 can extract the compensation value of the pixel that has been designated as being located at the center of the selected block into a representative value M. For example, if the block has m columns and n rows, the pixel located at the center of the selected block can be selected as one of the following: a pixel corresponding to information about its position corresponding to m / 2 columns and n / 2 rows; a pixel corresponding to information about its position closest to m / 2 columns and n / 2 rows; or a pixel corresponding to information about its position adjacent to m / 2 columns and n / 2 rows. The compensation value of the selected pixel can then be extracted into the representative value M.

[0074] Furthermore, the compression unit 40 can extract the compensation value corresponding to the intermediate value as a representative value M. For example, the intermediate value between the maximum and minimum values ​​(i.e., (maximum value + minimum value) / 2) is "28.4", and the compensation value "28" as the closest value can be extracted as the representative value M.

[0075] On the other hand, the compression unit 40 can calculate the average value of the compensation values ​​of the pixels included in the selected block, and can extract the compensation value corresponding to the average value as a representative value M. For example, if the average value of the compensation values ​​of the pixels included in the selected block is "28", the compensation value "28" can be extracted as the representative value M. Furthermore, if the average value of the compensation values ​​of the pixels included in the selected block is "28.4", the compensation value "28", which is the closest value, can be extracted as the representative value M.

[0076] In the following text, for the sake of description, we assume that the representative value M is "28".

[0077] After extracting the representative value M of the block as described above, the compression unit 40 extracts the difference Diff between the representative value M and the compensation value of each pixel (S42).

[0078] exist Figure 5An exemplary two-dimensional table and a primary compression diagram BAC of the block BA obtained by primary compression through compression unit 40 are shown. Figure 3 In this context, the representative value of block BA is indicated as M11. This can be understood as... Figure 5 In the table, the representative value M11 corresponds to the reference value. Figure 4 The representative value M described is "28".

[0079] The compression unit 40 can calculate the difference between the representative value "28" and the compensation value of the pixel of the block, and can extract the difference Diff as the calculation result. For example, the difference between the compensation value "26" and the representative value "28" can be extracted as "-2", the difference between the compensation value "28" and the representative value "28" can be extracted as "0", and the difference between the compensation value "29" and the representative value "28" can be extracted as "1".

[0080] Compression unit 40 performs quantization (S44) to represent the difference Diff extracted in step S42 as a preset number of bits.

[0081] By quantization, compression unit 40 can convert the difference Diff within a range (within which the difference Diff can be represented as a preset number of bits) into a quantized binary value with a number of bits suitable for the corresponding value.

[0082] If the difference value Diff deviates from the range where the difference value Diff can be represented as a preset number of bits, then the difference value Diff can be set to a preset value.

[0083] For example, a difference Diff having a value larger than that which can be represented as a preset number of bits is quantized to the maximum value that can be represented as a preset number of bits. Furthermore, a difference Diff having a value smaller than that which can be represented as a preset number of bits is quantized to the minimum value that can be represented as a preset number of bits.

[0084] As a detailed example, suppose the maximum value that can be represented as a preset number of bits is "4" and the minimum value that can be represented as a preset number of bits is "-3". Then, the difference Diff "5" can be quantized to the value corresponding to the maximum value "4" because the difference Diff "5" is greater than the value that can be represented as the preset number of bits for quantization. The difference Diff "-4" can be quantized to the value corresponding to the minimum value "-3" because the difference Diff "-4" is less than the value that can be represented as the preset number of bits for quantization.

[0085] Compression unit 40 can generate a bitmap, i.e. a primary compressed map (S46), by mapping the difference Diff that has been quantized based on the pixel-based position information map as described above. Figure 5 The primary compressed image BAC in the image shows a bitmap in which the quantized difference Diff has been mapped for each pixel.

[0086] Compression unit 40 can generate a representative value M and a primary compression graph of the block through primary compression.

[0087] Subsequently, compression unit 40 performs secondary compression on the representative value M of the block. (See reference) Figures 6 to 8 Describes the secondary compression of compression unit 40.

[0088] Compression unit 40 is a two-dimensional table MA representing the representative value M corresponding to the secondary compression structure and block. The two-dimensional table MA representing the representative value M can be referenced. Figure 7 To understand.

[0089] The compression unit 40 can construct a two-dimensional table MA representing the value M by using the block position information of the block. That is, the representative value M can be mapped to the two-dimensional table MA based on the position of the block arranged on the screen.

[0090] Compression unit 40 can perform secondary compression by using differential coding.

[0091] Compression unit 40 can set a reference value R in the representative value M of the block of the two-dimensional table MA for differential encoding (S60).

[0092] The reference value R can be understood as a first value used to encode the values ​​that change sequentially. In embodiments of this disclosure, the representative value M11 located in the first column of the first row of the two-dimensional table MA can be used as the reference value R.

[0093] When a reference value R is set, the compression unit 40 performs differential encoding on the representative value M of the two-dimensional table MA using the reference value R (S62). The compression unit 40 can generate the encoded value generated as the result of the differential encoding. Figure 7 The secondary compressed graph MAC (S64) corresponding to the block and representing the value M.

[0094] refer to Figure 8 Describe the differential coding method.

[0095] exist Figure 8 In this context, the numbers within the block boxes correspond to the representative values ​​of the blocks. That is, the numbers within the block boxes correspond to the values ​​that the representative value M of the block has been mapped to for each position in the two-dimensional table MA.

[0096] It can be understood that differential encoding includes calculating encoded values ​​obtained by calculating the differences between representative values ​​of adjacent columns and by calculating the differences between representative values ​​of adjacent rows belonging to the first column, as well as generating a two-dimensional table MAC by mapping the encoded values ​​using a method based on block location information. The encoded values ​​correspond to... Figure 8The numbers within the circles. The two-dimensional table MAC generated as described above is equivalent to a secondary compressed map of the representative values ​​of the blocks generated through embodiments of this disclosure.

[0097] More specifically, the coded value "0" corresponding to the first column of the first row of the secondary compressed graph corresponds to the difference between the reference value R and the representative value "28" located in the first column of the first row of the two-dimensional table MA. The coded value "1" corresponding to the second column of the first row of the secondary compressed graph corresponds to the difference between the representative value "28" located in the first column of the first row of the two-dimensional table MA and the representative value "29" located in the second column of the first row of the two-dimensional table MA. The coded value can be calculated by using this method to calculate the difference between the representative values ​​of adjacent columns.

[0098] Furthermore, the coded value "0" corresponding to the first column of the first row of the secondary compressed graph corresponds to the difference between the reference value R and the representative value "28" located in the first column of the first row of the two-dimensional table MA. The coded value "1" corresponding to the first column of the second row of the secondary compressed graph corresponds to the difference between the representative value "28" located in the first column of the first row of the two-dimensional table MA and the representative value "29" located in the first column of the second row of the two-dimensional table MA. The coded value can be calculated by using this method to calculate the difference between the representative values ​​of adjacent rows belonging to the first column.

[0099] Compression unit 40 can generate a secondary compression map and a reference value R for secondary compression by performing secondary compression on the representative value M of the block.

[0100] As described above, the compression unit 40 can generate a primary compressed graph corresponding to the block through primary compression, and can generate a secondary compressed graph corresponding to the reference value R and representative value M of the block through secondary compression.

[0101] The compression information storage unit 50 can store a primary compression map, a reference value R, and a secondary compression map as compensation information, and can also store the reference value R later according to the manufacturer's intentions. Figure 9 The described display driver device provides compensation information.

[0102] The above-described embodiments of this disclosure can effectively compress compensation information through primary compression of blocks and secondary compression of representative values ​​of blocks.

[0103] Furthermore, the compensation information can be compressed into a small size using the compression method according to embodiments of this disclosure. As a result, the memory capacity used to store the compensation information can be reduced.

[0104] Furthermore, in embodiments of this disclosure, the compression of the representative value of a block and the compression of the compensation value of a block can be performed separately in block-based compression. Therefore, when an error occurs within a block, the propagation of the error is confined to that block. Thus, the increase in error due to error propagation can be suppressed.

[0105] Furthermore, the embodiments of this disclosure can solve the problem of block artifacts that mainly occur in block-based compression, since the compensation values ​​of pixels are compressed on a block-by-block basis.

[0106] Furthermore, in embodiments of this disclosure, since secondary compression is performed using adjacent blocks that typically have similar values, the loss can be small or non-existent. Therefore, the compression ratio of the compensation information can be improved.

[0107] like Figure 9 As shown, display data is provided to timing controller 100. Timing controller 100 constructs a PKT (packetized display data) and provides the PKT to display driver device 110.

[0108] The display driver 110 is configured to recover display data after receiving the packet PKT, generate a source signal Sout corresponding to the display data, and provide the source signal Sout to the display panel 120.

[0109] For example, Figure 9 The display driver device 110 in the middle can be as follows Figure 10 It is constructed in that way.

[0110] refer to Figure 10 The display driving device 110 may include a group receiving unit 200, a defect compensation unit 210, a source signal generation unit 220, a source signal output unit 230, a compensation information storage unit 250, and a compensation value generation unit 260.

[0111] The packet receiving unit 200 receives the display data packets PKT provided by the timing controller 100 and recovers the display data from the packet PKT.

[0112] The defect compensation unit 210 has a structure for compensating for defects by using the compensation equation of Equation 1, and compensates the display data so that the defects are resolved by applying the compensation value provided by the compensation value generation unit 260 to each pixel.

[0113] The source signal generation unit 220 drives the source signal Sout based on the compensated display data. The source signal output unit 230 provides the source signal Sout driven by the source signal generation unit 220 to the display panel 120.

[0114] The compensation information storage unit 250 can be constructed using a memory such as flash memory. The compensation information storage unit 250 can store information based on... Figure 1 The compensation information generated by the implementation method (i.e., primary compression map, reference value R and secondary compression map) can be provided to the compensation value generation unit 260.

[0115] The compensation value generation unit 260 converts the encoded values ​​of the secondary compressed map into representative values ​​for the multiple blocks into which the screen is divided using a reference value. In other words, the compensation value generation unit 260 performs decoding on the secondary compression. More specifically, the compensation value generation unit 260 can generate representative values ​​for multiple blocks by decoding the encoded values ​​of the differentially encoded secondary compressed map MAC using a reference value R, and thus can generate a two-dimensional table MA of representative values.

[0116] Subsequently, the compensation value generation unit 260 converts the differences in the primary compressed image into compensation values ​​corresponding to the pixels of the respective blocks by using the representative value of each block. In other words, the compensation value generation unit 260 performs decoding on the primary compression. More specifically, the compensation value generation unit 260 can generate a two-dimensional table BA of compensation values ​​for each block by adding each difference in the primary compressed image BAC to the representative value of a two-dimensional table MA, which is the result of decoding the secondary compressed image MAC.

[0117] The compensation value generation unit 260 can provide coefficient values ​​to the defect compensation unit 210 through decoding, that is, the screen compensation value for each pixel.

[0118] The defect compensation unit 210 receives the display data from the group receiving unit 200 and the compensation value from the compensation value generation unit 260 for each pixel.

[0119] The defect compensation unit 210 can compensate the display data by using a compensation equation in which the compensation value has been applied to the coefficient value, and can output the compensated display data.

[0120] More specifically, the defect compensation unit 210 can compensate for the display data by substituting the coefficient values ​​of the coefficients for each pixel provided by the compensation value generation unit 260 as described above into the compensation equation of Equation 1.

[0121] Therefore, the display driver device according to this disclosure can store and provide compensation values ​​by using a memory with a small capacity, and can compensate for defects such as mura very well, while preventing artifacts by using a two-dimensional compensation bitmap to use compressed values ​​that are correlated between adjacent data.

Claims

1. An apparatus for providing compensation information for demura, the apparatus comprising: The compensation value providing unit is configured to provide compensation values ​​for pixels; as well as The compression unit is configured to divide the screen into multiple blocks, generate a primary compression map and a representative value of the primary compression by performing primary compression on the compensation value for each block, and generate a secondary compression map and a reference value of the secondary compression by performing secondary compression on the representative value of the block. The primary compression includes: Extract the representative value of the compensation value of the block; Extract the difference between the representative value and the compensation value; and A primary compressed map corresponding to the pixels of the block is generated using the difference, and The secondary compression includes: Set the reference value of the representative value; Differential encoding is performed on the representative value using the reference value; and A secondary compressed map corresponding to the block is generated by generating the encoded values ​​as a result of the differential encoding. The representative value includes any one of the following: the compensation value of the pixel located at the center of each block, the intermediate compensation value between the maximum and minimum compensation values ​​of the pixels in each block, and the average compensation value of the pixels in each block. The reference value is set in the representative value of the block in the two-dimensional table corresponding to the block.

2. The device according to claim 1, wherein, The compensation value providing unit provides the coefficient values ​​of the coefficients of the compensation equation used for the demura of the pixel as the compensation value.

3. The device according to claim 1, wherein, The compression unit provides the primary compression map, the reference value, and the secondary compression map as the compensation information.

4. The device according to claim 1, wherein, The compensation value providing unit provides the position information of the pixel and the compensation value, and The compression unit generates a primary compressed map mapped by the difference using the location information, and a secondary compressed map mapped by the encoded values ​​corresponding to the blocks.

5. The device according to claim 1, wherein, The primary compressed map includes a two-dimensional table corresponding to the pixels of the block, and The secondary compression graph includes a two-dimensional table corresponding to the block.

6. The device according to claim 1, wherein, The compression unit extracts the compensation value of the pixel that has been set at the center of the block as the representative value.

7. The device according to claim 1, wherein, The compression unit is configured to: The calculation includes the intermediate value between the maximum and minimum values ​​of the compensation values ​​for the pixels in the block; and The compensation value corresponding to the intermediate value is extracted as the representative value.

8. The device according to claim 1, wherein, The compression unit is configured to: Calculate the average value of the compensation values ​​of the pixels included in the block; and The compensation value corresponding to the average value is extracted as the representative value.

9. The device according to claim 1, wherein, The compression unit is configured to: Perform quantization to represent the extracted difference as a preset number of bits; and The bitmap including the quantized difference is generated as the primary compressed map.

10. The device according to claim 9, wherein, The compression unit sets the difference that has deviated from the range in which the extracted difference can be represented by the preset number of bits as a preset value through the quantization.

11. The device according to claim 10, wherein, The compression unit is configured to: The difference that has a value greater than the value that can be represented as the preset number of bits is quantized into the maximum value that can be represented as the preset number of bits; as well as The difference between values ​​that are smaller than the value that can be represented by the preset number of bits is quantized into the minimum value that can be represented by the preset number of bits.

12. A method for providing compensation information for demura, the method comprising: Divide the screen into multiple blocks; Primary compression is performed on the compensation values ​​of pixels in each block, and a primary compressed map and a representative value of the primary compression are generated through the primary compression. as well as Secondary compression is performed on the representative values ​​of the block, and a secondary compression map and a reference value for the secondary compression are generated from the secondary compression. The primary compression includes: Extract the representative value of the compensation value of the block; Extract the difference between the representative value and the compensation value; and A primary compressed map corresponding to the pixels of the block is generated using the difference, and The secondary compression includes: Set the reference value of the representative value; Differential encoding is performed on the representative value using the reference value; and A secondary compressed map corresponding to the block is generated by generating the encoded values ​​as a result of the differential encoding. The representative value includes any one of the following: the compensation value of the pixel located at the center of each block, the intermediate compensation value between the maximum and minimum compensation values ​​of the pixels in each block, and the average compensation value of the pixels in each block. The reference value is set in the representative value of the block in the two-dimensional table corresponding to the block.

13. The method according to claim 12, wherein, The compensation value corresponds to the coefficient value of the coefficients in the compensation equation used for the demura of the pixel.

14. The method according to claim 12, wherein, The primary compressed map includes a two-dimensional table corresponding to the pixels of the block, and The secondary compression graph includes a two-dimensional table corresponding to the block.

15. The method according to claim 12, wherein, The representative value corresponds to the compensation value of the pixel that has been set at the center of the block.

16. The method of claim 12, further comprising: Calculate the intermediate value between the maximum and minimum values ​​of the compensation values ​​for the pixels included in the block; as well as The compensation value corresponding to the intermediate value is extracted as the representative value.

17. The method according to claim 12, wherein, The representative value corresponds to the average value of the compensation values ​​of the pixels included in the block.

18. The method of claim 12, further comprising: Perform quantization to represent the extracted difference as a preset number of bits. The primary compressed image is generated as a bitmap including the quantized difference, and The quantization includes setting a preset value to the difference that has deviated from the range in which the extracted difference can be represented by the preset number of bits.

19. A display driver device, comprising: The compensation information storage unit is configured to store and provide a primary compressed map with differences, a secondary compressed map with encoded values, and a reference value; The compensation value generation unit is configured to convert the encoded value of the secondary compressed map into a representative value of a plurality of blocks into which the screen is divided by using the reference value, convert the difference of the primary compressed map into a compensation value corresponding to the pixel of the corresponding block by using the representative value of each block, and provide the compensation value for each pixel. as well as The defect compensation unit is configured to receive display data and the compensation value for each pixel, compensate the display data using a compensation equation that has been applied to the coefficient values ​​of the compensation values, and output the compensated display data. Each of the representative values ​​includes any one of the following: the compensation value of the pixel located at the center of each block, the intermediate compensation value between the maximum and minimum compensation values ​​of the pixels in each block, and the average compensation value of the pixels in each block. The reference value is set in the representative value of the block in the two-dimensional table corresponding to the block.

20. The display driving device according to claim 19, wherein, The compensation value generation unit is configured to: The representative value is generated by decoding the differentially encoded value using the reference value. as well as A compensation value corresponding to the pixel of the block is generated by adding the difference to each of the representative values.

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