Backlight compensation method and liquid crystal display device

Abstract

The present application discloses a backlight compensation method and a liquid crystal display device. The backlight compensation method first obtains the display brightness diffusion form fitting curve under the binding point grayscale based on the number of data drivers, then determines the display brightness compensation data according to the target brightness and the display brightness diffusion form fitting curve, and then obtains the backlight compensation data corresponding to the binding point grayscale according to the light diffusion function and the display brightness compensation data. The backlight brightness corresponding to the binding point grayscale can be adjusted, thereby reducing the difference in display brightness under the binding point grayscale, and thus improving the uneven brightness and dark phenomenon caused by the excessive impedance difference of the data line in the fan-shaped area.

Description

Technical Field

[0001] The present application relates to the field of display technology, and in particular to a backlight compensation method and a liquid crystal display device. Background Art

[0002] As display panels grow in size, the lengths of gate and data lines are also increasing. Gate signals transmitted in gate lines or data signals transmitted in data lines attenuate over long distances due to increased line impedance. One reason for this is that the impedance differences of corresponding conductors in the fan-out area lead to corresponding charging differences, resulting in noticeable macroscopic uneven brightness (fan-out mura). Summary of the Invention

[0003] The present application provides a backlight compensation method and a liquid crystal display device to alleviate the technical problem of uneven brightness caused by excessive impedance differences of data lines in a sector-shaped area.

[0004] In a first aspect, the present application provides a backlight compensation method, which includes: obtaining a display brightness diffusion morphology fitting curve under the binding point grayscale based on the number of data drivers; determining the display brightness compensation data according to the target brightness and the display brightness diffusion morphology fitting curve; and obtaining the backlight compensation data corresponding to the binding point grayscale according to the light diffusion function and the display brightness compensation data.

[0005] In some embodiments, the step of obtaining the display brightness diffusion morphology fitting curves under the binding point grayscale based on the number of data drivers includes: configuring the number of data drivers to N, where N is greater than or equal to 2; selecting N-1 rows of sub-pixels at equal intervals in the extension direction of the data line; and determining the number of display brightness diffusion morphology fitting curves based on the number of rows of sub-pixels selected at equal intervals.

[0006] In some embodiments, based on the number of data drivers, the step of obtaining the display brightness diffusion shape fitting curve under the binding point grayscale also includes: obtaining a corresponding display brightness diffusion shape fitting curve based on the brightness of each sub-pixel in each row of sub-pixels selected at equal intervals under the overload screen.

[0007] In some embodiments, the step of determining display brightness compensation data based on the target brightness and the display brightness diffusion form fitting curve includes: determining the target brightness as the display brightness close to the data driver and located in the middle area in the data line arrangement direction; and determining the display brightness compensation data of each display partition based on the target brightness and each display brightness in each display brightness diffusion form fitting curve.

[0008] In some embodiments, the step of determining the display brightness compensation data of each display partition based on the target brightness and each display brightness in the display brightness diffusion form fitting curve includes: determining the display brightness compensation data of a corresponding display partition based on the difference between the target brightness and each display brightness in a display brightness diffusion form fitting curve.

[0009] In some embodiments, the step of obtaining backlight compensation data corresponding to the binding point grayscale based on the light diffusion function and the display brightness compensation data includes: configuring the projection of each backlight partition in the light emitting direction to overlap with each display partition; and obtaining the backlight compensation data of each backlight partition based on the division result of the display brightness compensation data and the light diffusion function.

[0010] In some embodiments, after the step of obtaining the display brightness diffusion form fitting curves under the binding point grayscale based on the number of data drivers, it also includes: obtaining the display brightness diffusion form fitting curves under multiple binding point grayscales; based on the display brightness diffusion form fitting curves under each binding point grayscale, obtaining the display brightness diffusion form fitting curves under other grayscales by linear interpolation.

[0011] In some embodiments, after the step of obtaining the backlight compensation data corresponding to the binding point grayscale according to the light diffusion function and the display brightness compensation data, the step also includes: obtaining the corresponding backlight compensation data under other grayscales; aggregating the corresponding backlight compensation data under all grayscales into a backlight compensation data table; storing the backlight compensation data table in a backlight compensation unit; accumulating the backlight compensation data under the display grayscale to the backlight original data corresponding to the display screen according to the display grayscale of the display screen; and driving the backlight according to the accumulation result of the backlight compensation data under the display grayscale and the backlight original data corresponding to the display screen.

[0012] In some embodiments, after the step of driving the backlight according to the cumulative result of each backlight compensation data under the display grayscale and the backlight original data corresponding to the display screen, the step also includes: judging the brightness uniformity of the display screen after backlight compensation; if the brightness uniformity does not meet the requirements, executing the step of "obtaining the fitting curve of the display brightness diffusion shape under the binding point grayscale based on the number of data drivers".

[0013] In a second aspect, the present application provides a liquid crystal display device, which executes the backlight compensation method in at least one of the above-mentioned embodiments.

[0014] The backlight compensation method and liquid crystal display device provided in the present application first obtain the display brightness diffusion form fitting curves under the binding point gray scale based on the number of data drivers, then determine the display brightness compensation data according to the target brightness and the display brightness diffusion form fitting curve, and then obtain the backlight compensation data corresponding to the binding point gray scale according to the light diffusion function and the display brightness compensation data. The backlight brightness corresponding to the binding point gray scale can be adjusted, thereby reducing the difference in display brightness under the binding point gray scale, and thus improving the uneven brightness and dark phenomenon caused by the excessive impedance difference of the data line in the fan-shaped area. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The following detailed description of the specific embodiments of the present application in conjunction with the accompanying drawings will make the technical solutions and other beneficial effects of the present application apparent.

[0016] Figure 1 Schematic diagram of the structure of the impedance difference between conductors in a sector area in the related art.

[0017] Figure 2 A schematic diagram showing the output delay of a data signal in the related art.

[0018] Figure 3 This is a schematic diagram of the first flow chart of the backlight compensation method provided in an embodiment of the present application.

[0019] Figure 4 This is a second flow chart of the backlight compensation method provided in an embodiment of the present application.

[0020] Figure 5 A schematic diagram of the structure of a liquid crystal display panel provided in an embodiment of the present application.

[0021] Figure 6 A schematic diagram of a brightness diffusion morphology fitting curve provided in an embodiment of the present application. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0023] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or suggesting relative importance or implicitly indicating the number of the indicated technical features. The features specified as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0024] Figure 1 This diagram illustrates the impedance differences between conductors in a fan-shaped area of the display. The conductor connected to the central data driver has the smallest resistance (Rmin), resulting in a higher pixel charge rate and a brighter pixel. The conductors on either side have the largest resistance (Rmax), resulting in a lower pixel charge rate and a darker pixel. When the resistance difference between data lines (Source), Rmax-Rmin, exceeds 300Ω, or when the resistance difference between gate lines (Gate), Rmax-Rmin, exceeds 200Ω, fan-out mura will appear on the display.

[0025] Here, fan-out height refers to the height of the fan-out area. Line width refers to the line width of a data line or gate line. Spacing refers to the spacing between two adjacent data lines or between two adjacent gate lines.

[0026] By changing the metal layer thickness and material of the data or gate lines, the overall resistance and resistance differences between metal lines can be reduced, thus mitigating fan-out mura. However, changing the metal layer thickness can significantly alter the electrical properties of the entire display panel, especially in large-scale display panels, which can lead to new defects and increase costs.

[0027] Related technologies can also use ODDC (Output Data Delay Compensation) to control the output delay of all output channels of the data driver to charge to the same voltage value within the same time to reduce fan-out mura. However, ODDC is rarely used and can only roughly repair fan-out mura, but cannot fully repair fan-out mura. For example, Figure 2 As shown in the figure, after ODDC is turned on, there is an obvious difference between the area where the dotted line and the dotted arrow are located and the middle area at the bottom.

[0028] In view of the technical problem of uneven brightness caused by large impedance differences of the data lines in the sector-shaped area mentioned above, this embodiment provides a backlight compensation method, please refer to Figures 3 to 6 ,like Figure 3 As shown, the backlight compensation method includes the following steps:

[0029] Step S10: obtaining the display brightness diffusion form fitting curves under the binding point grayscale based on the number of data drivers.

[0030] That is, step S10 is used to perform the following steps: Figure 4The collected Fanout mura diffusion morphology fitting curve shown is the brightness diffusion morphology fitting curve.

[0031] Step S20: determining display brightness compensation data according to the target brightness and the display brightness diffusion form fitting curve.

[0032] That is, step S20 is used to perform the following steps: Figure 4 The fanout mura compensation data shown is calculated based on the display brightness compensation data.

[0033] Step S30: obtaining backlight compensation data corresponding to the grayscale of the binding point according to the light diffusion function and the display brightness compensation data.

[0034] That is, step S30 is used to perform the following steps: Figure 4 The backlight compensation data shown is calculated.

[0035] It can be understood that the backlight compensation method provided in this embodiment first obtains the display brightness diffusion form fitting curve under the binding point gray scale based on the number of data drivers, and then determines the display brightness compensation data according to the target brightness and the display brightness diffusion form fitting curve. Then, the backlight compensation data corresponding to the binding point gray scale is obtained according to the light diffusion function and the display brightness compensation data. The backlight brightness corresponding to the binding point gray scale can be adjusted, thereby reducing the difference in display brightness under the binding point gray scale, and thus improving the uneven brightness and dark phenomenon caused by the excessive impedance difference of the data line in the fan-shaped area.

[0036] It should be noted that the data driver is used to output data signals, which are transmitted through data lines to charge corresponding pixels. In order to reduce the area, the data driver can also be presented in the form of a chip.

[0037] Among them, since the bottom position of the display panel is close to the data driver, the impedance loss is small and the pixels here are more fully charged. Therefore, the target brightness is generally selected as the brightness at the bottom position of the display panel, which can improve the uniformity of the display brightness while improving the overall display brightness.

[0038] In one embodiment, the step of obtaining the display brightness diffusion morphology fitting curves under the binding point grayscale based on the number of data drivers includes: configuring the number of data drivers to be N, where N is greater than or equal to 2; selecting N-1 rows of sub-pixels at equal intervals in the extension direction of the data line; and determining the number of display brightness diffusion morphology fitting curves based on the number of rows of sub-pixels selected at equal intervals.

[0039] It's important to note that since all data drivers are arranged horizontally across the width of the display panel, the charging effect is better near the data drivers than farther away. The area between the data drivers has the worst charging effect. We refer to this type of mura as fanout mura. For example, if a display panel uses four data drivers, with three gaps between them, there will be three distinct fanout mura lines. Each fanout mura line corresponds to a display brightness diffusion fitting curve. This can effectively eliminate or improve uneven brightness.

[0040] In one embodiment, the step of obtaining the display brightness diffusion shape fitting curve under the binding point grayscale based on the number of data drivers also includes: obtaining a corresponding display brightness diffusion shape fitting curve based on the brightness of each sub-pixel in each row of sub-pixels selected at equal intervals under the heavy-load screen.

[0041] It needs to be explained that, Figure 5 As shown, assuming that the display panel adopts eleven data drivers, the display area of the display panel is divided into 10 parts with equal intervals in the vertical direction, as shown by the horizontal dotted lines for each row of sub-pixels.

[0042] Among them, along the vertical direction shown by the arrow in the figure, from top to bottom, the position of the bottom 1 / 3 of the panel, the position of the middle 1 / 2 of the panel, and the position of the top 1 / 3 of the panel are marked in sequence.

[0043] In one embodiment, the step of determining display brightness compensation data based on the target brightness and the display brightness diffusion form fitting curve includes: determining the target brightness as the display brightness close to the data driver and located in the middle area in the data line arrangement direction; and determining the display brightness compensation data of each display partition based on the target brightness and each display brightness in each display brightness diffusion form fitting curve.

[0044] It should be noted that obtaining Figure 5 The brightness of each sub-pixel in each row of sub-pixels corresponding to the horizontal dotted line is shown, and the brightness of each sub-pixel in each row of sub-pixels is imported into the matlab software to obtain the following Figure 6 The corresponding display brightness diffusion morphology fitting curves are shown.

[0045] Among them, Figure 6 In FIG, the horizontal axis 1-97 is used to represent the position of the corresponding sub-pixel in the display panel; the vertical axis is used to represent the brightness.

[0046] The brightness of each sub-pixel can be captured by a camera to obtain raw image data, and the raw image data includes the coordinates and brightness of each sub-pixel.

[0047] In one embodiment, the step of determining display brightness compensation data for each display partition based on the target brightness and each display brightness in each display brightness diffusion form fitting curve includes: determining the display brightness compensation data for a corresponding display partition based on the difference between the target brightness and each display brightness in a display brightness diffusion form fitting curve.

[0048] In one embodiment, the step of obtaining backlight compensation data corresponding to the grayscale of the binding point based on the light diffusion function and the display brightness compensation data includes: configuring the projection of each backlight partition in the light emitting direction to overlap with each display partition; and obtaining the backlight compensation data of each backlight partition based on the division result of the display brightness compensation data and the light diffusion function.

[0049] It should be noted that since the backlight is some distance away from the liquid crystal, when the light propagates within this distance, it will spread to not only the pixels directly above the backlight, but also overflow to the adjacent pixels. Therefore, there is a light diffusion function in the backlight partition adjustment (local dimming) algorithm. The backlight value multiplied by the light diffusion function is the brightness value of the pixel where the backlight is transmitted to the display.

[0050] Therefore, after obtaining the display brightness compensation data, the corresponding backlight compensation data is obtained by dividing it by the light diffusion function.

[0051] In one embodiment, after the step of obtaining the display brightness diffusion form fitting curves under the binding point grayscale based on the number of data drivers, it also includes: obtaining the display brightness diffusion form fitting curves under multiple binding point grayscales; based on the display brightness diffusion form fitting curves under each binding point grayscale, obtaining the display brightness diffusion form fitting curves under other grayscales by linear interpolation method.

[0052] It should be noted that first obtaining the display brightness diffusion shape fitting curves under multiple binding point grayscales, and then obtaining the display brightness diffusion shape fitting curves under other grayscales through linear interpolation can save the above processing of the backlight compensation method, simplify the links, and improve efficiency.

[0053] In one embodiment, the grayscale image of the binding point is obtained according to the light diffusion function and the display brightness compensation data.

[0054] After the step of obtaining backlight compensation data corresponding to the grayscale, the method further includes: obtaining backlight compensation data corresponding to other grayscales; collecting backlight compensation data corresponding to all grayscales into a backlight compensation data table; storing backlight compensation data;

[0055] The compensation data table is added to the backlight compensation unit. Figure 4 The data is stored as shown; according to the display grayscale of the display screen, the backlight compensation data under the display grayscale is accumulated to the backlight original data corresponding to the display screen; according to the accumulation result of the backlight compensation data under the display grayscale and the backlight original data corresponding to the display screen, the backlight is driven.

[0056] In one embodiment, after the step of driving the backlight according to the accumulation result of each backlight compensation data under the display grayscale and the backlight original data corresponding to the display screen, the step further includes: determining the brightness uniformity of the display screen after backlight compensation, that is, Figure 4 The backlight compensation effect is determined as shown; if the brightness uniformity does not meet the requirements, the step of "obtaining the display brightness diffusion morphology fitting curve under the binding point grayscale based on the number of data drivers" is executed.

[0057] 5 It should be noted that this process can be repeated until the backlight compensation effect is satisfied.

[0058] Until the judgment requirement is met.

[0059] In one embodiment, the present embodiment provides a liquid crystal display device, which executes the backlight compensation method of at least one of the above embodiments.

[0060] It is understandable that the liquid crystal display device provided in this embodiment can also be realized by firstly performing the backlight compensation method based on the data driver, because the liquid crystal display device implements the backlight compensation method in at least one of the above embodiments.

[0061] The brightness diffusion fitting curve of each display under the grayscale of the binding point is obtained, and the display brightness compensation data is determined according to the target brightness and the brightness diffusion fitting curve. Then, the backlight compensation data corresponding to the grayscale of the binding point is obtained according to the light diffusion function and the display brightness compensation data. The backlight compensation data corresponding to the grayscale of the binding point can be adjusted.

[0062] The brightness is improved, which reduces the difference in display brightness under the grayscale of the binding point, thereby improving the uneven brightness caused by the large impedance difference of the data line in the sector area.

[0063] It should be noted that the liquid crystal display device may include a liquid crystal display panel and a backlight module. The liquid crystal display panel includes a display area, which may include one or more display sub-areas. The backlight module may include a backlight area, which may include multiple backlight sub-areas. The backlight brightness of each backlight sub-area can be independently controlled or adjusted.

[0064] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0065] The above is a detailed introduction to the backlight compensation method and liquid crystal display device provided in the embodiments of the present application. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solutions and core ideas of the present application. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A backlight compensation method, characterized in that: The backlight compensation method comprises: Based on the number of data drivers, obtaining the display brightness diffusion morphology fitting curves at the grayscale of the binding point; Determining display brightness compensation data according to the target brightness and the display brightness diffusion morphology fitting curve; Obtaining backlight compensation data corresponding to the grayscale of the binding point according to the light diffusion function and the display brightness compensation data; The step of obtaining the fitting curve of each display brightness diffusion form under the grayscale of the binding point based on the number of data drivers includes: Configuring the number of the data drivers to be N, where N is greater than or equal to 2; Select N-1 rows of sub-pixels at equal intervals in the extending direction of the data line; The number of the display brightness diffusion morphology fitting curves is determined based on the number of rows of sub-pixels selected at equal intervals.

2. The backlight compensation method according to claim 1, wherein: The step of obtaining the fitting curves of the display brightness diffusion forms at the binding point grayscale based on the number of data drivers further includes: According to the brightness of each sub-pixel in each row of sub-pixels selected at equal intervals under a heavy-load image, a corresponding display brightness diffusion shape fitting curve is obtained.

3. The backlight compensation method according to claim 2, wherein: The step of determining display brightness compensation data according to the target brightness and the display brightness diffusion form fitting curve includes: Determining the target brightness as the display brightness of a region close to the data driver and located in the middle in the data line arrangement direction; Display brightness compensation data of each display partition is determined according to the target brightness and each display brightness in the display brightness diffusion form fitting curve.

4. The backlight compensation method according to claim 3, wherein: The step of determining display brightness compensation data of each display partition according to the target brightness and each display brightness in the display brightness diffusion form fitting curve includes: Display brightness compensation data of a corresponding display partition is determined according to a difference between the target brightness and each display brightness in the display brightness diffusion form fitting curve.

5. The backlight compensation method according to claim 4, wherein: The step of obtaining backlight compensation data corresponding to the grayscale of the binding point according to the light diffusion function and the display brightness compensation data includes: Configuring the projection of each backlight partition in the light emitting direction to overlap with each of the display partitions; Backlight compensation data of each backlight subarea is obtained according to a division result of the display brightness compensation data and the light diffusion function.

6. The backlight compensation method according to claim 1, wherein: After the step of obtaining the fitting curves of the display brightness diffusion forms at the grayscale of the binding point based on the number of data drivers, the method further includes: Obtaining the fitting curve of each display brightness diffusion shape under multiple binding point grayscales; Based on the display brightness diffusion form fitting curves at each binding point grayscale, the display brightness diffusion form fitting curves at other grayscales are obtained by linear interpolation.

7. The backlight compensation method according to claim 1, wherein: After the step of obtaining the backlight compensation data corresponding to the grayscale of the binding point according to the light diffusion function and the display brightness compensation data, the method further includes: Obtaining backlight compensation data corresponding to other grayscales; Gathering the corresponding backlight compensation data under all grayscales into a backlight compensation data table; Storing the backlight compensation data table in a backlight compensation unit; According to the display grayscale of the display picture, accumulating each backlight compensation data at the display grayscale to the backlight original data corresponding to the display picture; The backlight is driven according to the accumulation result of each backlight compensation data under the display grayscale and the backlight original data corresponding to the display picture.

8. The backlight compensation method according to claim 7, wherein: After the step of driving the backlight according to the accumulation result of each backlight compensation data at the display grayscale and the backlight original data corresponding to the display image, the method further includes: Determine the brightness uniformity of the display screen after backlight compensation; If the brightness uniformity does not meet the requirement, the step of "obtaining the display brightness diffusion morphology fitting curve under the binding point grayscale based on the number of data drivers" is performed.

9. A liquid crystal display device, characterized in that: The liquid crystal display device performs the backlight compensation method according to any one of claims 1 to 8.

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