De-unevenness tuning for 2D backlight systems

Abstract

A method for de-unevenness calibration is provided. The method includes acquiring a plurality of luminance maps of a plurality of light sources of a two-dimensional backlight system for a plurality of test patterns, each test pattern indicating each of the plurality of light sources to be turned on or off. Each of the plurality of light sources is turned on in only one of the plurality of test patterns. The plurality of luminance maps indicate luminance levels of the plurality of light sources for the plurality of test patterns. The method further includes generating a cumulative luminance map by adding the plurality of luminance maps together. The method further includes generating a de-unevenness compensation factor for the plurality of light sources based on the cumulative luminance map.

Description

[0001] Cross-reference to related applications This application claims priority to U.S. Patent Application No. 18 / 798005, filed August 8, 2024, entitled “DEMURA TUNING FOR 2D BACKLIGHT SYSTEMS”, and U.S. Provisional Patent Application No. 63 / 590868, filed October 17, 2023, both entitled “DEMURATUNING FOR 2D BACKLIGHT SYSTEMS”, which are incorporated herein by reference in their entirety. Technical Field

[0002] This disclosure generally relates to demura tuning for two-dimensional (2D) backlight systems. Background Technology

[0003] Local dimming based on two-dimensional (2D) backlighting is one of the technologies used to improve the contrast of liquid crystal display (LCD) devices. Local dimming technology can achieve high dynamic contrast and low power consumption by individually controlling the corresponding light source (e.g., light-emitting diodes (LEDs)) of the 2D backlight system according to the input image data.

[0004] The image quality of an LCD device with local dimming functionality can largely depend on the characteristics of the backlight system's light source. A major problem in LCD devices with local dimming is that brightness uniformity can deteriorate due to variations in the optical characteristics of the corresponding light source.

[0005] Unevenness correction is a brightness compensation technique used to improve the brightness uniformity of LCD devices with 2D backlight systems. It works by applying an unevenness compensation factor to the brightness value of the corresponding light source, which is determined based on the characteristics of the light source. This factor is stored as unevenness data in the LCD device and used to correct image inhomogeneities.

[0006] In some implementations, the de-uniformity compensation factor for the corresponding light source can be determined during the tuning or calibration process of the LCD device. The tuning process may involve operating the corresponding light source of the 2D backlight system to illuminate the LCD panel according to a predetermined test pattern, and acquiring a brightness map on the LCD panel for the corresponding test pattern. The de-uniformity compensation factor for the corresponding light source can be determined based on the acquired brightness map. Summary of the Invention

[0007] The summary of this invention is provided to introduce, in a simplified form, the concepts further described below. This summary is not intended to necessarily identify key or essential features of this disclosure. This disclosure may include various aspects and embodiments.

[0008] In one exemplary embodiment, this disclosure provides a method. The method includes acquiring multiple brightness maps of multiple light sources of a two-dimensional backlight system for multiple test patterns, each test pattern indicating each of the multiple light sources to be turned on or off. Each of the multiple light sources is turned on according to only one of the multiple test patterns. The multiple brightness maps indicate the brightness level of the multiple light sources for the multiple test patterns. The method further includes acquiring multiple brightness maps... Figure 1 The light sources are added together to generate a cumulative luminance map. The method further includes generating a deuniformity compensation factor for the plurality of light sources based on the cumulative luminance map.

[0009] In another exemplary embodiment, this disclosure provides a calibration system including a processor and a storage device. The storage device is configured to store computer-executable instructions, which, when executed, cause the processor to acquire multiple brightness maps of multiple light sources of a two-dimensional backlight system for multiple test patterns, each test pattern indicating each of the multiple light sources to be turned on or off. Each of the multiple light sources is turned on according to only one of the multiple test patterns. The multiple brightness maps indicate the brightness levels of the multiple light sources for the multiple test patterns. When executed, the computer-executable instructions further cause the processor to: acquire multiple brightness maps of multiple light sources for the multiple test patterns. Figure 1 The light sources are added together to generate a cumulative luminance map; and based on the cumulative luminance map, a de-uniformity compensation factor is generated for the plurality of light sources.

[0010] In yet another exemplary embodiment, this disclosure provides a non-transitory tangible computer-readable storage medium for de-uniformity calibration of a display device including a two-dimensional backlight system. The non-transitory tangible computer-readable storage medium stores computer-executable instructions that, when executed, cause a processor to acquire multiple brightness maps of multiple light sources of the two-dimensional backlight system for multiple test patterns, each test pattern indicating each of the multiple light sources to be turned on or off. Each of the multiple light sources is turned on according to only one of the multiple test patterns. The multiple brightness maps indicate the brightness levels of the multiple light sources for the multiple test patterns. When executed, the computer-executable instructions further cause the processor to: [the processor then...] Figure 1 The light sources are added together to generate a cumulative luminance map; and based on the cumulative luminance map, a de-uniformity compensation factor is generated for the plurality of light sources. Attached Figure Description

[0011] Figure 1 An example configuration of a display device suitable for local dimming functionality according to one or more embodiments is shown.

[0012] Figure 2 Illustrations according to one or more embodiments Figure 1 The example side view configuration of the display device shown is illustrated.

[0013] Figure 3 An example arrangement of the light source of a 2D backlight system according to one or more embodiments is shown.

[0014] Figure 4 An example test pattern for measuring the light diffusion characteristics of each light source is shown according to one or more embodiments.

[0015] Figure 5 Example light diffusion characteristics acquired through a fitting process according to one or more embodiments are shown.

[0016] Figure 6 Examples of contributions from ambient light sources to the total luminance of the area corresponding to the central light source are shown according to one or more embodiments.

[0017] Figure 7 An example test pattern is shown according to one or more embodiments for illuminating a display panel and measuring the brightness level of a corresponding light source.

[0018] Figure 8 The use according to one or more embodiments is shown Figure 7 The four test patterns shown are used to capture example images.

[0019] Figure 9 An example process for generating a cumulative brightness map of the entire light source array is shown according to one or more embodiments.

[0020] Figure 10 An example scheme for generating an unevenness compensation factor is shown according to one or more embodiments.

[0021] Figure 11 An example scheme for calculating a compensated luminance map is shown according to one or more embodiments.

[0022] Figure 12 An example configuration of a calibration system according to one or more embodiments is shown.

[0023] Figure 13 An example configuration of a display driver according to one or more embodiments is shown.

[0024] To facilitate understanding, the same reference numerals have been used where possible to denote elements common to the figures. It is contemplated that elements disclosed in one embodiment may be utilized in other embodiments without specific description. Suffixes may be appended to reference numerals to distinguish elements from one another. Unless specifically indicated, the figures mentioned herein should not be construed as being drawn to scale. Furthermore, for clarity of presentation and explanation, the figures are generally simplified, and details or components are omitted. The figures and discussion are used to explain the principles discussed below. Detailed Implementation

[0025] The following detailed descriptions are exemplary in nature and are not intended to limit this disclosure or its application and use. Furthermore, they are not intended to be construed as being bound by any express or implied theory presented in the foregoing background, summary of the invention, and accompanying drawings or the following detailed descriptions.

[0026] In the following detailed embodiments, numerous specific details are set forth in order to provide a more thorough understanding of the disclosed technology. However, it will be apparent to those skilled in the art that the disclosed technology can be practiced without these specific details. In other instances, well-known features have not been described in detail to avoid unnecessarily complicating this description.

[0027] As used herein, the term "coupled" means directly connected to or connected via one or more intermediate components or circuits. Furthermore, throughout this application, ordinal numbers (e.g., first, second, third, etc.) may be used as adjectives for elements (i.e., any noun in this application). The use of ordinal numbers is not intended to imply or create any particular ordering of elements, nor to limit any element to a single element, unless explicitly disclosed through the use of terms such as "before," "after," "single," and other such terms. Rather, the use of ordinal numbers is intended to distinguish between elements. As an example, a first element is different from a second element, and a first element may contain more than one element and is ordered after (or before) the second element.

[0028] Figure 1 An example configuration of a display device 1000 suitable for local dimming functionality according to one or more embodiments is shown. The display device 1000 includes a liquid crystal display (LCD) panel 100, a two-dimensional (2D) backlight system 200, and a display driver 300. The 2D backlight system 200 is configured to illuminate the display panel 100. The 2D backlight system 200 includes an array of light sources 210. Note that the light sources 210... Figure 1 The image is shown in dashed lines because the light source 210 is as follows: Figure 2 The image shown is located behind the display panel 200. Figure 2 The illustration shows the side view configuration of device 1000. Although in Figure 1 The diagram shows 64 light sources 210, but those skilled in the art will recognize that the 2D backlight system 200 may include more or fewer than 64 light sources 210. In practical implementations, the 2D backlight system 200 may include hundreds to thousands of light sources 210. In one implementation, each light source 210 may include an LED or a different type of light source.

[0029] Figure 3 An example arrangement of light sources 210 for a 2D backlight system 200 according to one or more embodiments is shown. In the illustrated embodiment, the display panel 100 is divided into rectangular (e.g., square) areas 110 arranged in rows and columns, and light sources 210 are located behind corresponding areas 110. Each light source 210 is positioned such that the projection of each light source 210 onto the display panel 100 is located at the center (e.g., geometric center) of the corresponding area 110. As used herein, a “corresponding area” 110 of a light source 210 refers to the area 110 that includes the projection of that light source 210 onto the display panel 100. It should be noted that due to the light diffusion characteristics of the light sources 210, each light source 210 primarily illuminates the corresponding area 110, but may secondaryly illuminate at least a portion of the area 110 surrounding (e.g., adjacent to) the corresponding area 110.

[0030] Return to reference Figure 1 The display driver 300 is configured to receive input image data representing an input image from an external image source (not shown) and drive the display panel 100 to display an image corresponding to the input image data. The input image data may include pixel data of the corresponding pixels of the input image. The pixel data of a pixel may include the grayscale level of the corresponding primary color (e.g., red (R), green (G), and blue (B)).

[0031] The display driver 300 is further configured to implement a local dimming function by individually controlling the corresponding light source 210 of the 2D backlight system 200 according to the input image data. The local dimming function can determine the base brightness value of the corresponding light source 210 based on the input image data. The base brightness value of each light source 210 can correspond to the desired illuminance level of that light source 210. The base brightness value of the target light source 210 can be determined based on the pixel data of the pixels located in the corresponding area 110 of the target light source 210. In some implementations, the base brightness value of the target light source 210 can be further determined based on the pixel data of the pixels located in at least a portion of the area 110 adjacent to the corresponding area 110 of the target light source 210.

[0032] The display driver 300 is further configured to perform a de-uniformity function during the control of the light source 210 of the 2D backlight system 200. In one implementation, the display driver 300 may be configured to store de-uniformity data including a de-uniformity compensation factor, and apply the stored de-uniformity compensation factor to the base luminance value of the corresponding light source 210 to generate a compensated luminance value for the corresponding light source 210. The 2D backlight system 200 may be configured to cause the corresponding light source 210 to emit light at an illuminance level indicated by the compensated luminance value.

[0033] De-uniformity data can be generated during the tuning or calibration process of the display device 1000. Various techniques are disclosed according to various embodiments of this disclosure for efficiently determining the de-uniformity compensation factor for the corresponding light source of the 2D backlight system. Alternatively, the de-uniformity data or de-uniformity compensation factor can be dynamically generated during normal use of the display device 1000.

[0034] In one or more embodiments, the tuning process for determining the deuniformity compensation factor of the light source of the 2D backlight system can evaluate the light diffusion characteristics of each light source 210. Figure 4 Example test patterns for measuring the light diffusion characteristics of each light source 210 are shown according to one or more embodiments. These test patterns are associated with two adjacent light sources and are determined under the assumption that the light sources 210 of the 2D backlight system 200 have the same light diffusion characteristics. Figure 4 The left image shows the first test pattern in which one of the leftmost light sources 210 is "turned on". Figure 4 The middle image shows a second test pattern in which another light source 210, located on the right, is "connected," and... Figure 4 The right image shows a third test pattern in which two of the light sources 210 are "connected," Figure 4 The white square in the diagram indicates the light source 210 that has been switched on. The term "switched on" may mean that the light source is driven to emit light at a predetermined brightness level (e.g., the maximum permissible brightness level).

[0035] In one or more embodiments, the illuminance distribution of the one-hot light source (left and right) and the two-hot light source can be used as shown in... Figure 5 The three test patterns shown in the curve on the left are used for observation. Further, a fitting process is implemented to estimate the parameters of the distribution function that best fits the light diffusion characteristics of each light source. In one implementation, such as... Figure 5 The intermediate curve shown illustrates the Cauchy distribution fitting process to estimate the parameters of the Cauchy distribution that best fits the light diffusion characteristics of each light source. Figure 5 The right curve plot shows an example of the estimated light diffusion characteristics of each light source acquired through the Cauchy distribution fitting process.

[0036] refer to Figure 6 This disclosure recognizes that the total luminance level of the region corresponding to a given light source (which may be referred to as the center light source) is a result of the combined light output of the center light source and its surrounding light sources forming a 3x3 light source array. In the illustrated embodiment, the center light source is responsible for approximately 30% of the total luminance level, while the surrounding light sources contribute approximately 70%. In one or more embodiments, a tuning process generates a directional filter representing the light diffusion characteristics of the light source based on an estimated distribution function (e.g., an estimated Cauchy distribution). The directional filter may represent the respective contributions of the center light source and its surrounding light sources of the associated 3x3 light source array to the total luminance level of the region of interest. In one embodiment, the directional filter may include directional coefficients assigned to the center light source and surrounding light sources of the associated 3x3 light source array. An example of a directional filter is shown in... Figure 6 This is shown as a 3x3 matrix. As discussed later, the directional filter is used to calculate the brightness compensation factor for each light source.

[0037] In one or more embodiments, the tuning process may further include acquiring a brightness map of the light source 210. The brightness map may indicate the brightness level of the corresponding light source 210 across the entire light source array. A de-uniformity compensation factor may be calculated based on the brightness map. One problem is that, as for... Figure 6 The light diffusion characteristics of the corresponding light source 210 discussed may be affected by the surrounding light sources.

[0038] refer to Figure 7 To accurately determine the brightness level of each light source 210, multiple test patterns are used to illuminate the display panel during the tuning process. Each test pattern indicates which of the multiple light sources should be turned on or off. The test patterns are determined such that each of the light sources 210 is turned on according to only one test pattern. The tuning process may include: acquiring multiple brightness maps of the light sources 210 for each of the multiple test patterns; and passing the multiple brightness maps... Figure 1 The cumulative luminance map is generated by adding the two images together. Based on this cumulative luminance map, a deuniformity compensation factor for the corresponding light source can be generated.

[0039] In one or more embodiments, it can be used during the tuning process. Figure 7The four test patterns #1, #2, #3, and #4 shown illuminate the display panel. The four test patterns #1, #2, #3, and #4 are determined such that the brightness level of each light source (e.g., an LED) does not significantly affect the measurement of the brightness level of the light sources surrounding that light source. In one or more embodiments, the four test patterns #1 to #4 may be defined such that each light source is turned on according to only one of the four test patterns #1 to #4. In some embodiments, a first group of light sources 210 may be turned on according to test pattern #1, a second group of light sources 210 may be turned on according to test pattern #2, a third group of light sources 210 may be turned on according to test pattern #3, and a fourth group of light sources 210 may be turned on according to test pattern #4. In such embodiments, the first, second, third, and fourth groups of light sources 210 may not share a light source, and each light source 210 may belong to only one of the first, second, third, and fourth groups of light sources 210.

[0040] The four test patterns #1 to #4 can be further defined such that each activated light source 210 is surrounded only by or adjacent only to an activated light source 210. In other words, the four test patterns #1 to #4 can be further defined such that each activated light source 210 is horizontally, vertically, and diagonally adjacent to an activated light source 210. In one implementation, each activated light source 210 of test pattern #2 is horizontally adjacent to the corresponding activated light source 210 of test pattern #1, each activated light source 210 of test pattern #3 is vertically adjacent to the corresponding activated light source 210 of test pattern #1, and each activated light source 210 of test pattern #4 is diagonally adjacent to the corresponding activated light source 210 of test pattern #1.

[0041] Figure 8 The use according to one or more embodiments is shown. Figure 7 Example images captured by the four test patterns #1, #2, #3, and #4 shown. Four images can be captured by an imaging device (e.g., a camera) when the display panel 100 is illuminated by the four test patterns #1, #2, #3, and #4, respectively. Each captured image indicates the illuminance level distribution generated by the switched-on light source 210. The upper left image shows the illuminance level distribution generated by the four test patterns #1, #2, #3, and #4. Figure 7 The image shown illustrates an example illuminance level distribution captured by test pattern #1, and the upper right image shows an example illuminance level distribution captured by test pattern #2. The lower left image shows an example illuminance level distribution captured by test pattern #3, and the lower right image shows an example illuminance level distribution captured by test pattern #4. Figure 8As shown, the four test patterns #1, #2, #3, and #4 are defined such that a portion of the display panel illuminated by each of the switched-on light sources does not overlap with a portion of the display panel illuminated by any other switched-on light source. In one or more embodiments, the captured images are analyzed to generate luminance maps of the four test patterns #1 to #4, each luminance map indicating the luminance level of the switched-on light source.

[0042] like Figure 9 As shown, the brightness was then generated for the four test patterns #1 to #4. Figure 1 The values ​​are summed to generate a cumulative brightness map of the entire light source array. The cumulative brightness map indicates the brightness level of the corresponding light source in the entire light source array. Based on the resulting cumulative brightness map, a de-uniformity compensation factor is generated.

[0043] Figure 10 The illustration depicts an example process for generating de-imbalanced data or de-imbalanced compensation factors according to one or more embodiments. The process may include confirming, for example... Figure 10 The accuracy of the cumulative brightness map shown in the left part. More specifically, the simulated unevenness map can be corrected by applying a directional filter (for...). Figure 6 The simulated unevenness map is used to calculate the cumulative luminance map. The simulated unevenness map simulates the luminance unevenness that occurs on the display panel when it is illuminated by all light sources without anti-unevenness functionality. The simulated unevenness map is compared to a "full-on measurement" luminance map, which is generated based on an image captured when the display panel is illuminated by all light sources 210. If the simulated unevenness map is sufficiently similar to the "full-on measurement" luminance map, this indicates that the cumulative luminance map has been successfully generated. In this case, the cumulative luminance map is used to generate anti-unevenness data, as described below. If there is a significant difference between the simulated unevenness map and the full-on measurement luminance map, the generated cumulative luminance map can be discarded, and the process of acquiring luminance maps for the four test patterns described above can be repeated to successfully generate the cumulative luminance map.

[0044] Figure 10 The right portion of the diagram illustrates an example process, according to one or more embodiments, for generating de-uniformity data or de-uniformity compensation factors using a cumulative brightness map. The de-uniformity compensation factors can be determined recursively as follows: First, an initial set of de-uniformity compensation factors is determined, and then the compensated brightness map is computed by applying the initial de-uniformity compensation factors and a directional filter to the cumulative brightness map. Figure 11 An example scheme for calculating a compensated luminance map is shown according to one or more embodiments. In the illustrated embodiment, the luminance level of the light source (x, y) in the compensated luminance map can be calculated according to the following expression (1): Where (x, y) indicates the light source in the x-th row and y-th column of the light source array, BC 图像 (x, y) is the luminance level of the light source (x, y) in the compensated luminance map, C 图像 (xm, yn) is the combined luminance level of the light source (xm, yn) in the cumulative luminance diagram, Cf(xm, yn) is the deuniformity compensation factor for the light source (xm, yn), Dc(m, n) are the directional coefficients in the m-th row and n-th column of the directional filter, Σ m It is the sum of the rows for the directional filter, and Σ n This is the sum of the columns for the directional filter. Then, the difference between the target brightness level and the corresponding light source brightness level in the compensated brightness map is calculated, and the initial de-uniformity compensation factors are modified based on this difference to generate a new set of de-uniformity compensation factors. This new set of de-uniformity compensation factors is then used in a similar manner to calculate another compensated brightness map. This process is repeated until the ratio of the maximum to minimum brightness level in the compensated brightness map is sufficiently close to one. In one implementation, the recursive process is repeated until the ratio of the maximum to minimum brightness level in the compensated brightness map falls within the range of 1.0 - α and 1.0 + α, where α is a positive number sufficiently less than 1.0. The resulting de-uniformity compensation factors are stored in the display driver and used as de-uniformity data for implementing the de-uniformity function through the display driver.

[0045] Figure 12 An example configuration of a calibration system 2000 according to one or more embodiments is shown. The calibration system 2000 is configured to perform a tuning or calibration process to generate de-uniformity data and provide it to a display driver 300. The de-uniformity data may include a de-uniformity compensation factor for a corresponding light source 210. As described above, the display driver 300 may be configured to implement a local dimming function to determine a base luminance value of the corresponding light source 210 based on input image data. The display driver 300 may be further configured to implement a de-uniformity function by applying the de-uniformity compensation factor to the base luminance value of the corresponding light source 210 to generate a compensated luminance value for the corresponding light source 210. The 2D backlight system 200 may be configured to cause the corresponding light source 210 to emit light at an illuminance level indicated by the compensated luminance value.

[0046] In one or more embodiments, the calibration system 2000 includes an imaging device 2100 (e.g., a camera) and a main unit 2200. The imaging device 2100 is configured to capture an image of the display panel 100 to measure the illuminance distribution on the display panel 100 against a test pattern based on the captured image. In one or more embodiments, the imaging device 2100 is configured to measure (1) the "left" light source of two associated light sources being switched on (e.g., ...). Figure 4(as shown in the left image) the first illuminance distribution on the display panel 100 when (2) the "right" light source is turned on (as shown in the left image) Figure 4 (as shown in the intermediate image) the second illuminance distribution on the display panel 100; and (3) both associated light sources are turned on (as shown in the intermediate image). Figure 4 The third illuminance distribution on the display panel 100 when (as shown in the right image). Figures 4 to 6 The three illuminance distributions described are used to estimate the light diffusion characteristics of the light source 210 and generate a directional filter representing the light diffusion characteristics of the light source 210.

[0047] The imaging device 2100 can be further configured to target Figure 7 Images of the display panel 100 are captured using the test patterns #1 to #4 shown. In some embodiments, the imaging device 2100 may be configured to capture (1) a first image of the display panel 100 when the 2D backlight system 200 illuminates the display panel 100 using the test pattern #1; (2) a second image of the display panel 100 when the 2D backlight system 200 illuminates the display panel 100 using the test pattern #2; (3) a third image of the display panel 100 when the 2D backlight system 200 illuminates the display panel 100 using the test pattern #3; and (4) a fourth image of the display panel 100 when the 2D backlight system 200 illuminates the display panel 100 using the test pattern #4. The images captured for the test patterns #1 to #4 are used to generate de-equalization data for the de-equalization function (e.g., for the de-equalization function). Figures 7 to 10 (to describe), where the de-uniformity data includes the de-uniformity compensation factor of the corresponding light source 210.

[0048] In one or more embodiments, the main unit 2200 includes interface (I / F) circuitry 2210, storage device 2220, processor 2230, and interface circuitry 2240. In one or more embodiments, interface circuitry 2210 is configured to connect the main unit 2200 to imaging device 2100 via an interface, and interface circuitry 2240 is configured to connect the main unit 2200 to display driver 300 via an interface.

[0049] Storage device 2220 is configured as a non-transitory tangible computer-readable storage medium in which calibration software 2250 is stored. Calibration software 2250 includes computer-executable instructions for performing a tuning or calibration process of display device 1000. More specifically, calibration software 2250 may include computer-executable instructions that, when executed, cause processor 2230 to generate a pattern generation command that instructs display driver 300 to illuminate display panel 100 with a desired test pattern, the desired test pattern including… Figure 4 The test pattern shown and Figure 7The test patterns #1 to #4 are shown. The pattern generation command is provided to the display driver 300 via the interface circuit 2240.

[0050] The calibration software 2250 may further include computer-executable instructions that, when executed, cause the processor 2230 to generate control commands instruct the imaging device 2100 to capture an image of the display panel 100 when the display panel 100 is illuminated by a desired test pattern, the desired test pattern including... Figure 4 The three test patterns shown are Figure 7 The four test patterns #1 to #4 are shown. Control commands can be provided to the imaging device 2100 via interface circuit 2210.

[0051] The calibration software 2250 may further include computer-executable instructions that, when executed, cause the processor 2230 to target the image of the display panel 100. Figure 4 The three test patterns shown determine the illuminance distribution of the display panel 100, and the images are captured by the imaging device 2100 for those test patterns. Computer-executable instructions, when executed, further cause the processor 2230 to generate a directional filter based on the determined illuminance distribution. As discussed above, the directional filter may represent the respective contributions of the light source of interest (which may also be referred to as the center light source) and its surrounding light sources forming a 3x3 light source array to the total brightness level of the area corresponding to the light source of interest. The directional filter may include directional coefficients assigned to the center light source and surrounding light sources of the associated 3x3 light source array.

[0052] The calibration software 2250 may further include computer-executable instructions that, when executed, cause the processor 2230 to acquire data from the imaging device 2100 via the interface circuit 2210. Figure 7 The images captured by test patterns #1 to #4 shown are used to generate de-uniformity data, which may include de-uniformity compensation factors for the corresponding light source 210. This can be achieved by referring to the above description... Figure 10 The process described uses a directional filter to generate de-uniformity data. The de-uniformity data is provided to the display driver 300 via interface circuitry 2240.

[0053] The calibration software 2250 can be mounted on the storage device 2220 using a non-transitory tangible computer-readable recording medium 2300 that records the calibration software 2250. Alternatively, the calibration software 2250 can be provided to the calibration system 2000 as a computer program product that can be downloaded from a server.

[0054] In some embodiments, non-volatile memory (NVM) 400 may be coupled to display driver 300, and display driver 300 may be configured to store de-equalization data in NVM 400. In such embodiments, display driver 300 may be configured to retrieve de-equalization data from NVM 400 and use the retrieved de-equalization data to perform de-equalization functions.

[0055] Figure 13 An example configuration of a display driver 300 according to one or more embodiments is shown. The display driver 300 is configured to perform local dimming and de-uniformity functions as described above. In the illustrated embodiment, the display driver 300 includes an image processing circuit 310, a driver circuit 320, an image analysis circuit 330, an interface (I / F) circuit 340, a de-uniformity data memory 350, and a backlight control circuit 360.

[0056] Image processing circuit 310 is configured to perform image processing on input image data to generate processed image data. Image processing performed by image processing circuit 310 may include color adjustment, unevenness correction, deburn correction, image scaling, gamma transformation, or other image processing. Driver circuit 320 is configured to receive the processed image data from image processing circuit 310 and drive corresponding pixels of display panel 100 based at least in part on the processed image data.

[0057] Image analysis circuitry 330 is configured to analyze input image data to generate analysis data. The analysis data may include information indicating the brightness of the input image surrounding each light source 210. In some embodiments, the analysis data may include calculations based on the input image data for each region 110 (in...). Figure 3 The average image level (APL) is shown in the figure. In other embodiments, the image analysis circuit 330 may be configured to: (1) select a target image portion of the input image for each light source 210, such that the target image portion includes the corresponding region 110 of the light source 210; (2) apply filtering to the target image portion to generate a filtered image portion for each light source 210; and (3) calculate the APL of the filtered image portion generated for each light source 210. In such embodiments, the analysis data may include the APL of the filtered image portion generated for each light source 210. The analysis data is provided to the backlight control circuit 360 and is used to implement a local dimming function to individually control the illuminance level of the light source 210 of the 2D backlight system 200. The analysis data may also be provided to the image processing circuit 310. In such implementations, the image processing circuit 310 may process the input image data based on the analysis data.

[0058] Interface circuit 340 is configured to receive de-uniformity data from calibration system 2000 and store the de-uniformity data in NVM 400. Interface circuit 340 is further configured to retrieve de-uniformity data from NVM 400 during startup or power-on reset and store the retrieved de-uniformity data in de-uniformity data memory 350. De-uniformity data memory 350 is configured to provide the de-uniformity data to backlight control circuit 360 to implement the de-uniformity function.

[0059] The backlight control circuit 360 is configured to implement a local dimming function based on analyzed data. More specifically, the backlight control circuit 360 is configured to generate a base backlight value for each light source 210 based on the analyzed data. In some embodiments, the base backlight value for each light source 210 may be determined based on the APL of the corresponding region 110 of that light source 210. In other embodiments, the base backlight value for each light source 210 may be determined based on the APL of a filtered image portion generated for that light source 210, as described above. The backlight control circuit 360 is further configured to receive de-uniformity data from the de-uniformity data memory 350 and implement a de-uniformity function based on the received de-uniformity data. In one implementation, the de-uniformity data may include a de-uniformity compensation factor for the corresponding light source 210 of the 2D backlight system 200, and the backlight control circuit 360 may be configured to apply the de-uniformity compensation factor of the corresponding light source 210 to the base backlight value to generate a compensated backlight value. The compensated backlight value is provided to the backlight system 200 to control the illuminance level of the light source 210.

[0060] In some embodiments, the backlight control circuit 360 may include a test pattern generator 370, the test pattern generator 370 being configured to respond to a signal received from a calibration system 2000 via an interface circuit 340. Figure 12 (As shown in the diagram) The received pattern generation command controls the illuminance level of the light source 210 of the 2D backlight system 200. The test pattern generator 370 can be configured to generate a backlight value for the corresponding light source 210 in response to the pattern generation command, such that the display panel 100 is illuminated by the desired test pattern. More specifically, the test pattern generator 370 can be configured to generate a backlight value for the calibration system 2000 for... Figure 4 The three test patterns shown acquire the illuminance distribution on the display panel 100 and, based on the acquired illuminance distribution, generate a directional filter, causing the 2D backlight system 200 to illuminate the display panel 100 with backlight values ​​through those test patterns. The test pattern generator 370 can be further configured to generate test pattern values ​​for use in the calibration system 2000 for... Figure 7 When the four test patterns #1 to #4 shown capture images of the display panel 100 and generate de-uniformity data based on the captured images, the 2D backlight system 200 illuminates the backlight value of the display panel 100 through the test patterns #1 to #4.

[0061] Unless otherwise indicated herein or obviously contradicted by the context, the use of the terms “a (a and an)”, “the”, “at least one”, and similar designations in the context of describing the invention (especially in the context of the following claims) shall be interpreted to cover both the singular and the plural. Unless otherwise indicated herein or obviously contradicted by the context, the use of the term “at least one” followed by a list of one or more items (e.g., “at least one of A and B”) shall be interpreted to mean one item (A or B) selected from the listed items or any combination of two or more items (A and B) from the listed items. Unless otherwise indicated, the terms “comprising,” “having,” and “containing” shall be interpreted as open-ended terms (i.e., meaning “including but not limited to”). Unless otherwise indicated herein, the description of the range of values ​​herein is intended merely to serve as a shorthand method for individually referring to each individual value falling within that range, and each individual value is incorporated into this specification as it is individually described herein. Unless otherwise indicated herein or obviously contradicted by the context, all methods described herein can be performed in any suitable order. Unless otherwise claimed, the use of any and all examples or exemplary language (e.g., "such as") provided herein is merely intended to better illustrate the invention and does not limit the scope of the invention. The language in this specification should not be construed as indicating any unclaimed element as necessary for practicing the invention.

[0062] Exemplary embodiments are described herein. Variations of those exemplary embodiments may become apparent to those skilled in the art upon reading the foregoing description. The inventors anticipate that those skilled in the art will employ such variations where appropriate, and the inventors intend to practice the invention in ways other than those specifically described herein. Therefore, the invention includes all modifications and equivalents of the subject matter recited in the appended claims as permitted by applicable law. Furthermore, unless otherwise indicated herein or otherwise clearly contradicted by the context, the invention covers any combination of the elements described above in all their possible variations.

Claims

1. A method comprising: Multiple brightness maps of multiple light sources in a two-dimensional backlight system are acquired for multiple test patterns. Each test pattern indicates each of the multiple light sources to be turned on or off. Each of the multiple light sources is turned on according to only one of the multiple test patterns. The multiple brightness maps indicate the brightness level of the multiple light sources for the multiple test patterns. A cumulative brightness map is generated by adding the multiple brightness maps together; and The unevenness compensation factor for the multiple light sources is generated based on the cumulative brightness map.

2. The method as described in claim 1, wherein, The plurality of test patterns includes a first test pattern. A first group of light sources among the plurality of light sources is turned on according to the first test pattern, and a first remaining group of light sources among the plurality of light sources is turned off. In this case, each light source in the first group of light sources is adjacent to only one light source in the first remaining group of light sources.

3. The method as described in claim 2, wherein, The plurality of test patterns further include: The second test pattern is used to connect the second group of light sources among the plurality of light sources according to the second test pattern; The third test pattern, wherein the third group of light sources among the plurality of light sources is connected according to the third test pattern; and The fourth test pattern involves connecting the fourth group of light sources among the plurality of light sources according to the fourth test pattern. Among them, the first, second, third and fourth groups of light sources do not share a light source.

4. The method of claim 3, wherein, Each of the plurality of light sources belongs to one of the first, second, third, and fourth groups of light sources.

5. The method of claim 3, wherein, The first group of light sources includes a first light source. The second group of light sources includes a second light source that is horizontally adjacent to the first light source. The third group of light sources includes a third light source that is perpendicularly adjacent to the first light source, and... The fourth group of light sources includes a fourth light source that is diagonally adjacent to the first light source.

6. The method of claim 1, wherein, The acquisition of the multiple brightness maps from the multiple light sources includes: While the display panel is illuminated by the plurality of light sources through the plurality of test patterns, multiple images of the display panel are captured; and The plurality of brightness maps of the plurality of light sources are generated based on the plurality of images.

7. The method of claim 1, further comprising generating a directional filter representing the light diffusion characteristics of the plurality of light sources. in, The deuniformity compensation factor for generating the plurality of light sources is further based on the directional filter.

8. The method of claim 7, wherein, Generating the directional filter includes: The first illuminance distribution is collected based on the fifth test pattern, and two adjacent light sources among the plurality of light sources are connected according to the fifth test pattern; The second illuminance distribution is collected based on the sixth test pattern, and one of the two adjacent light sources is turned on according to the sixth test pattern; The third illuminance distribution is acquired based on the seventh test pattern, and the other light source among the two adjacent light sources is switched on according to the seventh test pattern; and The directional filter is generated based on the first, second, and third illuminance distributions.

9. The method of claim 7, wherein, The unevenness compensation factor for generating the plurality of light sources includes: The unevenness compensation factor and the directional filter are applied to the cumulative brightness map to generate a compensated brightness map; and The unevenness compensation factor is modified based on the compensated brightness map.

10. A calibration system, comprising: processor; as well as A storage device configured to store computer-executable instructions, which, when executed, cause the processor to: Multiple brightness maps of multiple light sources in a two-dimensional backlight system are acquired for multiple test patterns. Each test pattern indicates each of the multiple light sources to be turned on or off. Each of the multiple light sources is turned on according to only one of the multiple test patterns. The multiple brightness maps indicate the brightness level of the multiple light sources for the multiple test patterns. A cumulative brightness map is generated by adding the brightness maps together; and The unevenness compensation factor for the multiple light sources is generated based on the cumulative brightness map.

11. The calibration system of claim 10, wherein, The plurality of test patterns includes a first test pattern. A first group of light sources among the plurality of light sources is turned on according to the first test pattern, and a first remaining group of light sources among the plurality of light sources is turned off. In this case, each light source in the first group of light sources is adjacent to only one light source in the first remaining group of light sources.

12. The calibration system of claim 11, wherein, The plurality of test patterns further include: The second test pattern is used to connect the second group of light sources among the plurality of light sources according to the second test pattern; The third test pattern, wherein the third group of light sources among the plurality of light sources is connected according to the third test pattern; and The fourth test pattern involves connecting the fourth group of light sources among the plurality of light sources according to the fourth test pattern, and... Among them, the first, second, third and fourth groups of light sources do not share a light source.

13. The calibration system of claim 12, wherein, The first group of light sources includes a first light source. The second group of light sources includes a second light source that is horizontally adjacent to the first light source. The third group of light sources includes a third light source that is perpendicularly adjacent to the first light source, and... The fourth group of light sources includes a fourth light source that is diagonally adjacent to the first light source.

14. The calibration system of claim 10, further comprising an imaging device configured to capture a plurality of images of the display panel as the display panel is illuminated by the plurality of light sources through the plurality of test patterns. in, Acquiring the multiple brightness maps of the multiple light sources includes generating the multiple brightness maps of the multiple light sources based on the multiple images.

15. The calibration system of claim 10, wherein, When executed, the computer-executable instructions further cause the processor to generate a directional filter representing the light diffusion characteristics of the plurality of light sources, and, The unevenness compensation factor for generating the plurality of light sources is further based on the directional filter.

16. A non-transitory tangible computer-readable storage medium storing computer-executable instructions, which, when executed, cause a processor to: Multiple brightness maps of multiple light sources in a two-dimensional backlight system are acquired for multiple test patterns. Each test pattern indicates which of the multiple light sources should be turned on or off. Each of the multiple light sources is turned on according to only one of the multiple test patterns. The plurality of brightness maps indicate the brightness levels of the plurality of light sources for the plurality of test patterns; A cumulative brightness map is generated by adding the brightness maps together. as well as The unevenness compensation factor for the multiple light sources is generated based on the cumulative brightness map.

17. The non-transitory tangible computer-readable storage medium of claim 16, wherein, The plurality of test patterns includes a first test pattern. A first group of light sources among the plurality of light sources is turned on according to the first test pattern, and a first remaining group of light sources among the plurality of light sources is turned off. In this case, each light source in the first group of light sources is adjacent to only one light source in the first remaining group of light sources.

18. The non-transitory tangible computer-readable storage medium of claim 17, wherein, The plurality of test patterns further include: The second test pattern is used to connect the second group of light sources among the plurality of light sources according to the second test pattern; The third test pattern, wherein the third group of light sources among the plurality of light sources is connected according to the third test pattern; and The fourth test pattern involves connecting the fourth group of light sources among the plurality of light sources according to the fourth test pattern. Among them, the first, second, third and fourth groups of light sources do not share a light source.

19. The non-transitory tangible computer-readable storage medium of claim 18, wherein, The first group of light sources includes a first light source. The second group of light sources includes a second light source that is horizontally adjacent to the first light source. The third group of light sources includes a third light source that is perpendicularly adjacent to the first light source, and... The fourth group of light sources includes a fourth light source that is diagonally adjacent to the first light source.

20. The non-transitory tangible computer-readable storage medium of claim 16, wherein, When executed, the computer-executable instructions further cause the processor to generate a directional filter representing the light diffusion characteristics of the plurality of light sources, and, The unevenness compensation factor for generating the plurality of light sources is further based on the directional filter.

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