Voltage drop compensation method for amoled display panel and related device

Abstract

The application provides a voltage drop compensation method of an AMOLED display panel and related equipment, a brightness-gray scale response model of each sub-block is constructed according to the average brightness of each sub-block; the standard brightness of the AMOLED display panel is introduced into the brightness-gray scale response model of each sub-block, the virtual gray scale of each sub-block is obtained; and the difference between the virtual gray scale and the typical gray scale is solved, the gray scale compensation value is obtained to construct a plurality of compensation lookup tables, and is transmitted to a display driving chip; according to the resolution size of the AMOLED display panel, the compensation lookup tables are interpolated on the display driving chip, the compensation lookup tables with the same resolution size are obtained to adjust the input gray scale of the AMOLED display panel, the current voltage is compensated, the compensation result is obtained to adjust the display brightness of the display area of the AMOLED display panel, and the display uniformity of the AMOLED display panel is improved.

Description

Technical Field

[0001] This invention relates to the field of display technology, and in particular to a voltage drop compensation method and related equipment for AMOLED display panels. Background Technology

[0002] Active-matrix organic light-emitting diode (AMOLED) is a novel display technology characterized by fast response time, wide color gamut, high contrast, low dynamic power consumption, wide viewing angle, and simple structure. In recent years, medium-sized and large-sized AMOLED display panels have been increasingly deployed in products, evolving towards a better user experience. However, the display driver IC (DDIC) of AMOLED display panels is typically located at the edge of the panel. Due to the resistance of the pixel circuits, a voltage drop, known as IR drop, inevitably occurs in the power lines from the DDIC to each pixel circuit. As display resolution continues to improve, the IR drop varies depending on the position of the pixel circuits, inevitably leading to uneven brightness and even color difference issues caused by inconsistent light emission.

[0003] AMOLED display panels require various compensation techniques to address brightness unevenness and improve production yield. Since AMOLED is current-driven, the brightness of the pixel circuit is directly proportional to the current, which is provided by the driving thin-film transistors (TFTs) and is related to TFT characteristic parameters. These parameters include TFT mobility, threshold voltage, AMOLED driving voltage, and power supply voltage. Based on different principles, AMOLED compensation can be divided into two categories: internal compensation and external compensation. Internal compensation refers to directly compensating the TFT threshold voltage by improving the pixel circuit, for example, evolving from the earliest 2T1C structure to the current 7T2C structure. Obviously, this method increases circuit complexity, power consumption, and places more stringent requirements on panel manufacturing processes. External compensation refers to using external feedback circuits outside the panel to sense the current of each pixel circuit in a short time and adjust the grayscale of the input image accordingly. However, this method usually suffers from inaccurate current sensing (especially at low grayscale levels), inability to completely solve brightness unevenness caused by voltage drop, and high costs associated with the sensing and compensation CMOS circuits. In addition, some methods attempt to establish equivalent circuit models, estimate the voltage drop distribution of pixel circuits at different locations, and make corresponding compensations. However, such methods still require online measurement of the current or resistance of the display circuit, and are not very practical. Summary of the Invention

[0004] This invention provides a voltage drop compensation method and related equipment for AMOLED display panels. The purpose is to compensate for the voltage drop by calling an interpolated compensation lookup table to adjust the grayscale of the input AMOLED display panel without changing the display characteristics of the pixel driving circuit of the display panel, thereby adjusting the display brightness of each area of ​​the panel and improving the display uniformity of the AMOLED display panel.

[0005] To achieve the above objectives, the present invention provides a voltage drop compensation method for an AMOLED display panel, comprising:

[0006] Step 1: Collect brightness data of the AMOLED display panel display area at multiple typical gray levels;

[0007] Step 2: Divide the brightness data into blocks and calculate the average brightness of each block under multiple typical gray levels and the standard brightness of the AMOLED display panel under each typical gray level.

[0008] Step 3: Construct a brightness-grayscale response model for each block based on the average brightness of each block at each typical grayscale level. The brightness-grayscale response model is used to characterize the response relationship between the brightness and grayscale of each block.

[0009] Step 4: Import the standard brightness of the AMOLED display panel into the brightness-grayscale response model of each block to obtain the virtual grayscale of each block;

[0010] Step 5: Calculate the difference between the virtual grayscale and the corresponding typical grayscale of each block to obtain the grayscale compensation value of each block.

[0011] Step 6: Construct a compensation lookup table based on the grayscale compensation value of each block, and transmit the compensation lookup table to the display driver chip of the AMOLED display panel;

[0012] Step 7: Based on the resolution of the AMOLED display panel, interpolate the compensation lookup table on the display driver chip to obtain the interpolated compensation lookup table. The number of grayscale compensation values ​​in the interpolated compensation lookup table is equal to the resolution of the AMOLED display panel.

[0013] Step 8: Use the interpolated compensation lookup table to adjust the grayscale of the input AMOLED display panel in order to compensate for the current and voltage at each pixel position in the AMOLED display panel.

[0014] Furthermore, step 1 includes:

[0015] Simulate the pixel circuit of the AMOLED display panel to generate multiple typical gray levels;

[0016] The typical grayscale level is sequentially imported into the AMOLED display panel for display via the display driver chip;

[0017] Brightness data of the display area of ​​the AMOLED display panel at multiple typical gray levels were collected using a brightness acquisition device.

[0018] Furthermore, step 2 includes:

[0019] The brightness data is divided into m*n blocks, and each block is numbered. Each block includes brightness data for multiple pixel positions.

[0020] Based on the brightness data of each block, the average brightness of each block and the standard brightness of the entire AMOLED display panel are calculated. The standard brightness is the average brightness of the AMOLED display panel.

[0021] Furthermore, step 3 includes:

[0022] By combining the gamma characteristics of the brightness data, the average brightness of each block under multiple typical gray levels is logarithmically transformed to obtain the logarithm of multiple average brightness and the logarithm of multiple typical gray levels.

[0023] Using the logarithm of each average brightness as input and the logarithm of each typical gray level as output, a least-squares polynomial fitting is performed to obtain the brightness-gray level response model of each block, which is used to characterize the brightness-gray level response relationship of each block.

[0024] Furthermore, the brightness-grayscale response model for each block is as follows:

[0025]

[0026] Where GL represents the typical grayscale after logarithmic transformation, LL represents the average brightness after logarithmic transformation, k represents the polynomial coefficients, (m, n) represents the block index of the AMOLED display panel, and p represents the polynomial order.

[0027] Furthermore, by calculating the difference between the virtual grayscale and the corresponding typical grayscale of each block, the expression for the grayscale compensation value of each block is obtained as follows:

[0028] offset (m，n) =TG (m，n) -SG (m，n)

[0029] Among them, offset (m，n) TG represents the grayscale compensation value of the (m, n)th block. (m，n) SG represents the typical grayscale of the (m, n)th block. (m，n)This represents the virtual gray level of the (m, n)th block.

[0030] Furthermore, a compensation lookup table is constructed based on the grayscale compensation value of each block, including:

[0031] The overall brightness of the AMOLED display panel is used as a parameter;

[0032] Display brightness values ​​are divided into typical display brightness values ​​and atypical display brightness values;

[0033] Under typical display brightness values, a compensation lookup table is constructed by collecting the grayscale compensation values ​​of each block under typical display brightness values;

[0034] For atypical display brightness values, the compensation lookup table for typical display brightness values ​​is fitted by least squares first-order fitting to obtain the compensation lookup table for atypical display brightness values.

[0035] Furthermore, interpolating the compensation lookup table on the display driver chip includes:

[0036] Determine whether the grayscale input to the pixel circuit of the AMOLED display panel is a typical grayscale;

[0037] When the gray level input to the pixel circuit is a typical gray level, the compensation lookup table corresponding to the typical gray level is directly looked up. The compensation lookup table is then bilinearly interpolated to obtain the interpolated compensation lookup table. The interpolated compensation lookup table includes gray level compensation values ​​that are equal to the resolution of the AMOLED display panel.

[0038] When the grayscale input to the pixel circuit is an atypical grayscale, proportional interpolation is required based on the compensation lookup table of the typical grayscale with the smallest difference from the atypical grayscale. This results in a compensation lookup table of the atypical grayscale after interpolation, which includes grayscale compensation values ​​equal to the resolution of the AMOLED display panel.

[0039] The present invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements a voltage drop compensation method for an AMOLED display panel.

[0040] The present invention also provides a terminal device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement a voltage drop compensation method for an AMOLED display panel.

[0041] The above-described solution of the present invention has the following beneficial effects:

[0042] This invention collects brightness data of the display area of ​​an AMOLED display panel at multiple typical gray levels; divides the brightness data into blocks and calculates the average brightness of each block at multiple typical gray levels and the standard brightness of the AMOLED display panel at each typical gray level; constructs a brightness-gray level response model for each block based on the average brightness of each block at each typical gray level; imports the standard brightness of the AMOLED display panel into the brightness-gray level response model of each block to obtain the virtual gray level of each block; calculates the difference between the virtual gray level of each block and the corresponding typical gray level to obtain the gray level compensation value of each block; constructs a compensation lookup table based on the gray level compensation value of each block and transmits the compensation lookup table to the display driver chip of the AMOLED display panel; and interpolates the compensation lookup table on the display driver chip according to the resolution of the AMOLED display panel to obtain the interpolated compensation. A lookup table is used, and the number of grayscale compensation values ​​in the interpolated compensation lookup table is equal to the resolution of the AMOLED display panel. The grayscale of the input AMOLED display panel is adjusted by calling the interpolated compensation lookup table to compensate for the current and voltage at each pixel position in the AMOLED display panel. Compared with the prior art, the present invention uses an external compensation method for voltage drop compensation. By fitting the brightness data with the grayscale, a brightness-grayscale response model for different areas of the AMOLED display panel is established. Without changing the display characteristics of the AMOLED display panel display driver chip, the grayscale of the input AMOLED display panel is adjusted by calling the interpolated compensation lookup table to compensate for the current and voltage at each pixel position in the AMOLED display panel, thereby adjusting the display brightness of each area of ​​the AMOLED display panel and improving the display uniformity of the AMOLED display panel.

[0043] Other beneficial effects of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0044] Figure 1 This is a flowchart illustrating an embodiment of the present invention;

[0045] Figure 2 This is a schematic diagram illustrating the division of the AMOLED display panel into sub-regions in an embodiment of the present invention. Detailed Implementation

[0046] To make the technical problems, solutions, and advantages of this invention clearer, a detailed description will be provided below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0047] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0048] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a locking connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0049] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0050] This invention addresses existing problems by providing a voltage drop compensation method and related equipment for AMOLED display panels.

[0051] like Figure 1 As shown, an embodiment of the present invention provides a voltage drop compensation method for an AMOLED display panel, comprising:

[0052] Step 1: Collect brightness data of the AMOLED display panel display area at multiple typical gray levels;

[0053] Step 2: Divide the brightness data into blocks and calculate the average brightness of each block under multiple typical gray levels and the standard brightness of the AMOLED display panel under each typical gray level.

[0054] Step 3: Construct a brightness-grayscale response model for each block based on the average brightness of each block at each typical grayscale level. The brightness-grayscale response model is used to characterize the response relationship between the brightness and grayscale of each block.

[0055] Step 4: Import the standard brightness of the AMOLED display panel into the brightness-grayscale response model of each block to obtain the virtual grayscale of each block;

[0056] Step 5: Calculate the difference between the virtual grayscale and the corresponding typical grayscale of each block to obtain the grayscale compensation value of each block.

[0057] Step 6: Construct a compensation lookup table based on the grayscale compensation value of each block, and transmit the compensation lookup table to the display driver chip of the AMOLED display panel;

[0058] Step 7: Based on the resolution of the AMOLED display panel, interpolate the compensation lookup table on the display driver chip to obtain the interpolated compensation lookup table. The number of grayscale compensation values ​​in the interpolated compensation lookup table is equal to the resolution of the AMOLED display panel.

[0059] Step 8: Use the interpolated compensation lookup table to adjust the grayscale of the input AMOLED display panel in order to compensate for the current and voltage at each pixel position in the AMOLED display panel.

[0060] Specifically, step 1 includes:

[0061] Simulate the pixel circuit of the AMOLED display panel to generate multiple typical gray levels;

[0062] The typical grayscale level is sequentially imported into the AMOLED display panel for display via the display driver chip;

[0063] Brightness data of the display area of ​​the AMOLED display panel at multiple typical gray levels were collected using a brightness acquisition device.

[0064] The preferred method is to generate a set of 9 typical gray levels of RGBW using simulation software, assuming they are [G1, G2, G3, G4, G5, G6, G7, G8, G9]. In an environment without interference from other light sources, these gray levels are sequentially imported into the AMOLED display panel via the display driver chip to illuminate the panel. The brightness data collected by the brightness acquisition device is denoted as [L1i, L2i, L3i, L4i, L5i, L6i, L7i, L8i, L9i], where i represents the index number of different areas on the AMOLED display panel.

[0065] In this embodiment of the invention, the display driver chip is a device in the AMOLED display panel, and the function of the display driver chip is to import typical grayscale into the AMOLED display panel; while the brightness acquisition device includes, but is not limited to, a brightness acquisition meter, an industrial camera, etc., and this embodiment of the invention uses a brightness acquisition meter.

[0066] Specifically, step 2 includes:

[0067] The brightness data is divided into m*n blocks, and each block is numbered. Each block includes brightness data for multiple pixel positions.

[0068] Based on the brightness data of each block, the average brightness of each block and the standard brightness of the entire AMOLED display panel are calculated. The standard brightness is the average brightness of the AMOLED display panel.

[0069] In embodiments of the present invention, such as Figure 2 As shown, the AMOLED display panel is divided into m*n sub-regions with a size of 256×256. The size of each sub-region is the size that can be achieved by bilinear interpolation hardware. The brightness data corresponding to each sub-region is a block, so there are m*n blocks. Each block includes brightness data for multiple pixel positions. Each block is numbered in order from left to right and from top to bottom. When the display resolution is not divisible by 256, the right and bottom blocks are treated as separate areas for brightness value statistics according to their actual size.

[0070] In this embodiment of the invention, the average brightness of each block is calculated by summing the brightness data of multiple pixel positions and dividing by the number of pixels in the block, while the standard brightness of the entire AMOLED display panel is calculated by summing the average brightness of each block and dividing by the number of blocks.

[0071] Specifically, step 3 includes:

[0072] By combining the gamma characteristics of the brightness data, the average brightness of each block under multiple typical gray levels is logarithmically transformed to obtain the logarithm of multiple average brightness and the logarithm of multiple typical gray levels.

[0073] Using the logarithm of each average brightness as input and the logarithm of each typical gray level as output, a least-squares polynomial fitting is performed to obtain the brightness-gray level response model for each block.

[0074] In this embodiment of the invention, gamma characteristics refer to the human eye's perception of brightness data, and logarithmic transformation is the inverse gamma transformation. It should be noted that the response model parameters of different blocks are different, which can actually reflect the different voltage drops in the pixel circuits of the display panel due to different positions, ultimately leading to differences in brightness data. The least squares polynomial fitting is performed with the logarithm of the average brightness of each block as input and the logarithm of the corresponding typical gray level as output to obtain the brightness-gray level response model of each block and the fitting parameters during fitting, which are used to characterize the response relationship between the brightness and gray level of each block.

[0075] In this embodiment of the invention, the brightness-grayscale response model for each block is as follows:

[0076]

[0077] Where GL represents the typical grayscale after logarithmic transformation, LL represents the average brightness of each block after logarithmic transformation, k represents the polynomial coefficients, (m, n) represents the block index of the AMOLED display panel, and p represents the polynomial order.

[0078] The key to voltage drop compensation in AMOLED display panels lies in finding the matching relationship between brightness and grayscale. Ideally, the response relationship between brightness and grayscale for each block is as follows:

[0079] L num =L 255 *(G num / G 255 ) gamma

[0080] Where L represents brightness data, G represents gray level, and gamma = 2.2; however, due to circuit losses and other reasons, the gamma value of different pixel circuits is usually in the range of [1.8, 2.5].

[0081] Specifically, the expression for the grayscale compensation value of each block is obtained by calculating the difference between the virtual grayscale and the corresponding typical grayscale of each block:

[0082] offset (m，n) =TG (m，n) -SG (m，n)

[0083] Among them, offset (m，n) TG represents the grayscale compensation value of the (m, n)th block. (m，n) SG represents the typical grayscale of the (m, n)th block. (m，n) This represents the virtual gray level of the (m, n)th block.

[0084] Since AMOLED display panels are mainly Real RGB screens, the resistance characteristics of the pixel circuits for different color components (R, G, B) are different, causing uneven display brightness. In fact, the inconsistent luminous efficiency of different colors may even lead to more serious color cast. Therefore, it is necessary to use separate compensation lookup tables (LUTs). In this embodiment of the invention, for each typical gray level, a compensation lookup table can be constructed based on the gray level compensation value of each block. Each compensation lookup table contains only the gray level compensation value of one block. These tables are all stored in the random access memory (RAM) of the display driver chip.

[0085] Specifically, a compensation lookup table is constructed based on the grayscale compensation value of each block, including:

[0086] The overall brightness of the AMOLED display panel is used as a parameter;

[0087] Display brightness values ​​are divided into typical display brightness values ​​and atypical display brightness values;

[0088] Under typical display brightness values, a compensation lookup table is constructed by collecting the grayscale compensation values ​​of each block under typical display brightness values;

[0089] For atypical display brightness values, the compensation lookup table for typical display brightness values ​​is fitted by least squares first-order fitting to obtain the compensation lookup table for atypical display brightness values.

[0090] In practical applications, AMOLED display panels need to consider the uniformity of display effects under different background lighting conditions. Display Brightness Value (DBV) is typically used as a parameter for dimming. Observations show that the grayscale compensation values ​​of pixel circuits at the same location may differ under different DBV parameters. This is because AMOLED display panels use DBV to represent brightness control, and the precision of DBV is generally 6 / 8 / 10 / 12 bits. In this embodiment, 10 bits are used, resulting in 1024 levels, and DBV is divided into multiple intervals. In this embodiment, DBV3FF is used as the typical display brightness value, and other DBVs are considered atypical display brightness value intervals. To achieve good grayscale transition at low brightness, the AMOLED display panel uses multiple Gamma curves to control the entire DBV. Changes in DBV may cause changes in the display panel's Gamma curve. Therefore, during voltage drop compensation, a compensation lookup table for each color channel and typical grayscale under typical DBV brightness is first obtained. The grayscale compensation values ​​for atypical DBV are then fitted using the compensation lookup table under typical DBV.

[0091] In actual compensation, the compensation lookup table is first interpolated to obtain the grayscale compensation value for each pixel position on the entire screen.

[0092] Specifically, interpolation of the compensation lookup table is performed on the display driver chip, including:

[0093] Determine whether the grayscale input to the pixel circuit of the AMOLED display panel is a typical grayscale;

[0094] When the gray level input to the pixel circuit is a typical gray level, the compensation lookup table corresponding to the typical gray level is directly looked up. The compensation lookup table is then bilinearly interpolated to obtain the interpolated compensation lookup table. The interpolated compensation lookup table includes gray level compensation values ​​that are equal to the resolution of the AMOLED display panel.

[0095] When the grayscale input to the pixel circuit is an atypical grayscale, proportional interpolation is required based on the compensation lookup table of the typical grayscale with the smallest difference from the atypical grayscale. This results in a compensation lookup table of the atypical grayscale after interpolation, which includes grayscale compensation values ​​equal to the resolution of the AMOLED display panel.

[0096] In this embodiment of the invention, when the input grayscale of the pixel circuit is detected to be 0, that is, the input grayscale data is 0, no compensation is required and the 0 grayscale can be directly output; when the input grayscale data of the pixel circuit is detected to be a non-zero typical grayscale, the compensation lookup table is directly interpolated to obtain a grayscale compensation value that is equal to the resolution of the AMOLED display panel.

[0097] In this embodiment of the invention, an atypical gray level 58 is used as an example. This atypical gray level is located between the typical gray level 32 and the typical gray level 64, and the difference between the atypical gray level 58 and the typical gray level 64 is the smallest. Therefore, its compensation lookup table is based on the compensation lookup table of the typical gray level 64 and is obtained by directly multiplying by 58 / 64.

[0098] Since the pixel circuit of an AMOLED display panel is generally composed of three sub-pixel circuits (R, G, and B), regardless of the actual resolution, light-emitting material, and arrangement of each circuit, the luminous efficiency of the three sub-pixel circuits differs when they are lit separately. This results in differences in the grayscale luminous changes of color synthesis, which also differ from those of the sub-pixels. In this embodiment of the invention, all grayscale compensation values ​​in the luminous scenarios of the RGBW pixel circuits are saved, so that when dealing with the luminous situations of different sub-pixel circuits, the display driver chip can perform corresponding compensation by calling different compensation lookup tables.

[0099] In this embodiment of the invention, when the actual brightness of a typical grayscale is greater than the standard brightness when a certain sub-region is input, negative compensation is required for that typical grayscale; otherwise, positive compensation is required.

[0100] To address the potential issue of positive compensation in typical grayscale levels (where excessive positive compensation can lead to overcompensation and affect the actual compensation effect), resulting in the compensated input grayscale value exceeding 255, the compensation strategy is adjusted as follows:

[0101] The standard brightness of high grayscale (above 240) is set as the minimum brightness value of the m*n sub-region. Correspondingly, all other blocks that are brighter than the minimum brightness need to reduce the input grayscale to ensure negative compensation when the input grayscale is high. This avoids the possibility of positive compensation over-overflow and reduces power consumption and improves display uniformity when the grayscale is high.

[0102] To address the potential negative compensation issue in typical grayscale levels (where excessive negative compensation can lead to overcompensation and affect the actual compensation result), resulting in negative grayscale levels in the compensated input grayscale, the compensation strategy is adjusted as follows:

[0103] Set the standard brightness of low grayscale (below 16) to the maximum brightness value of m*n sub-regions. If a darker area has the same brightness as the block with the maximum brightness, the input grayscale must be increased. Blocks with the same brightness as the block with the maximum brightness do not need compensation. This can basically ensure positive compensation at low grayscale. Generally speaking, the lower the grayscale, the lower the display uniformity. Only by performing positive compensation on low grayscale can the display uniformity be improved.

[0104] In this embodiment of the invention, grayscale display brightness information before and after compensation is collected using a Demura image quality calibration device. The uniformity data of each grayscale level before and after compensation for the RGBW grayscale are shown in Table 1 below using a standard brightness uniformity statistical method:

[0105] Table 1

[0106]

[0107]

[0108] As can be seen from the data before compensation in Table 1 above, the lower the gray level, the lower the screen brightness uniformity; under the same gray level, the higher the DBV, the better the uniformity; after processing by the IR Drop compensation algorithm proposed in this embodiment of the invention, the brightness uniformity of each DBV gray level is significantly improved; the improvement is the largest for low gray levels, and the brightness uniformity of high gray levels after improvement is mostly 90%, or even above 95%; the IR Drop compensation algorithm proposed in this embodiment of the invention not only satisfies the improvement of brightness uniformity of different gray levels under the same DBV, but also satisfies the improvement of display characteristics of each gray level under different DBV, and the screen brightness uniformity correction effect is obvious.

[0109] It should be noted that the voltage drop compensation method provided in this embodiment of the invention is applicable not only to display scenarios with multiple resolution modes, but also to display panels with multiple refresh rate modes. For display panels with multiple refresh rate modes, the compensation process is as follows:

[0110] If the uniformity of the display panel remains within the required standard after switching refresh rates, then the compensation lookup table under the standard refresh rate can be used directly.

[0111] If a significant difference in uniformity occurs after switching refresh rates, it indicates that the brightness response of the display panel changes with the refresh rate. It is necessary to collect brightness data at the corresponding refresh rate, fit it with the compensation lookup table of the standard refresh rate, and then burn the fitting parameters of the compensation lookup table of the standard refresh rate into the RAM of the display driver chip.

[0112] This invention collects brightness data of the display area of ​​an AMOLED display panel at multiple typical gray levels; divides the brightness data into blocks and calculates the average brightness of each block at multiple typical gray levels and the standard brightness of the AMOLED display panel at each typical gray level; constructs a brightness-gray level response model for each block based on the average brightness of each block at each typical gray level; imports the standard brightness of the AMOLED display panel into the brightness-gray level response model of each block to obtain the virtual gray level of each block; calculates the difference between the virtual gray level of each block and the corresponding typical gray level to obtain the gray level compensation value of each block; constructs a compensation lookup table based on the gray level compensation value of each block and transmits the compensation lookup table to the display driver chip of the AMOLED display panel; and interpolates the compensation lookup table on the display driver chip according to the resolution of the AMOLED display panel to obtain the interpolated compensation. A lookup table is used, and the number of grayscale compensation values ​​in the interpolated compensation lookup table is equal to the resolution of the AMOLED display panel. The grayscale of the input AMOLED display panel is adjusted by calling the interpolated compensation lookup table to compensate for the current and voltage at each pixel position in the AMOLED display panel. Compared with the prior art, the embodiment of the present invention uses an external compensation method for voltage drop compensation. By fitting the brightness data with the grayscale, a brightness-grayscale response model for different areas of the AMOLED display panel is established. Without changing the display characteristics of the AMOLED display panel display driver chip, the grayscale of the input AMOLED display panel is adjusted by calling the interpolated compensation lookup table to compensate for the current and voltage at each pixel position in the AMOLED display panel, thereby adjusting the display brightness of each area of ​​the AMOLED display panel and improving the display uniformity of the AMOLED display panel.

[0113] This invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements a voltage drop compensation method for an AMOLED display panel.

[0114] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the embodiments of the present invention can implement all or part of the processes in the methods described above by instructing related hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the various method embodiments described above. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include at least: any entity or device capable of carrying the computer program code to a building device / terminal device, a recording medium, a computer memory, a read-only memory (ROM), a random access memory (RAM), an electrical carrier signal, a telecommunication signal, and a software distribution medium. Examples include USB flash drives, portable hard drives, magnetic disks, or optical disks. In some jurisdictions, according to legislation and patent practice, computer-readable media cannot be electrical carrier signals or telecommunication signals.

[0115] This invention also provides a terminal device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements a voltage drop compensation method for an AMOLED display panel.

[0116] It should be noted that the terminal device can be a mobile phone, tablet computer, laptop computer, Ultra-mobile Personal Computer (UMPC), netbook, Personal Digital Assistant (PDA), etc. For example, the terminal device can be a station (ST) in a WLAN, a cellular phone, cordless phone, Session Initiation Protocol (SIP) phone, Wireless Local Loop (WLL) station, PDA, handheld device with wireless communication capabilities, computing device or other processing device connected to a wireless modem, computer, laptop computer, handheld communication device, handheld computing device, satellite wireless device, etc. This embodiment of the invention does not impose any restrictions on the specific type of terminal device.

[0117] The processor referred to can be a Central Processing Unit (CPU), but it can also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor.

[0118] In some embodiments, the memory may be an internal storage unit of the terminal device, such as a hard drive or RAM. In other embodiments, the memory may be an external storage device of the terminal device, such as a plug-in hard drive, smart media card (SMC), secure digital card (SD), flash card, etc. Furthermore, the memory may include both internal and external storage units of the terminal device. The memory is used to store the operating system, applications, boot loader, data, and other programs, such as the program code of the computer program. The memory can also be used to temporarily store data that has been output or will be output.

[0119] It should be noted that the information interaction and execution process between the above-mentioned devices / units are based on the same concept as the method embodiments of the present invention. For details on their specific functions and technical effects, please refer to the method embodiments section, which will not be repeated here.

[0120] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A voltage drop compensation method for an AMOLED display panel, characterized in that, include: Step 1: Collect brightness data of the AMOLED display panel display area at multiple typical gray levels; Step 2: Divide the brightness data into blocks and calculate the average brightness of each block under multiple typical gray levels and the standard brightness of the AMOLED display panel under each typical gray level. The standard brightness is the average brightness of the AMOLED display panel. Step 3: Construct a brightness-grayscale response model for each block based on the average brightness of each block at each typical grayscale level. The brightness-grayscale response model is used to characterize the response relationship between the brightness and grayscale of each block. Step 4: Import the standard brightness of the AMOLED display panel into the brightness-grayscale response model of each block to obtain the virtual grayscale of each block; Step 5: Calculate the difference between the virtual grayscale and the corresponding typical grayscale of each block to obtain the grayscale compensation value of each block. Step 6: Construct a compensation lookup table based on the grayscale compensation value of each block, and transmit the compensation lookup table to the display driver chip of the AMOLED display panel; Step 7: Based on the resolution of the AMOLED display panel, interpolate the compensation lookup table on the display driver chip to obtain an interpolated compensation lookup table. The number of grayscale compensation values ​​in the interpolated compensation lookup table is equal to the resolution of the AMOLED display panel. Step 8: Call the interpolated compensation lookup table to adjust the grayscale of the AMOLED display panel to compensate for the current and voltage at each pixel position in the AMOLED display panel.

2. The voltage drop compensation method for an AMOLED display panel according to claim 1, characterized in that, Step 1 includes: The pixel circuit of the AMOLED display panel is simulated to generate multiple typical gray levels; Each typical grayscale level is sequentially imported into the AMOLED display panel for display via a display driver chip; The brightness data of the display area of ​​the AMOLED display panel at multiple typical gray levels are collected using a brightness acquisition device.

3. The voltage drop compensation method for an AMOLED display panel according to claim 2, characterized in that, Step 2 includes: The brightness data is divided into m*n blocks, and each block is numbered. Each block includes brightness data for multiple pixel positions. Based on the brightness data of each block, the average brightness of each block and the standard brightness of the entire AMOLED display panel are calculated.

4. The voltage drop compensation method for an AMOLED display panel according to claim 3, characterized in that, Step 3 includes: Based on the gamma characteristics of the brightness data, the average brightness of each block under multiple typical gray levels is logarithmically transformed to obtain the logarithm of multiple average brightness and the logarithm of multiple typical gray levels. Using the logarithm of each average brightness as input and the logarithm of each typical gray level as output, a least-squares polynomial fitting is performed to obtain the brightness-gray level response model of each block, which is used to characterize the response relationship between the brightness and gray level of each block.

5. The voltage drop compensation method for an AMOLED display panel according to claim 4, characterized in that, The brightness-grayscale response model for each block is as follows: in, This represents a typical grayscale after logarithmic transformation. This represents the average brightness after logarithmic transformation. Represents the polynomial coefficients. This indicates the block index of the AMOLED display panel. This indicates the order of the polynomial.

6. The voltage drop compensation method for an AMOLED display panel according to claim 5, characterized in that, The expression for the grayscale compensation value of each block is obtained by calculating the difference between the virtual grayscale and the corresponding typical grayscale of each block: in, Indicates the first Grayscale compensation values ​​for each block Indicates the first A typical grayscale of a block. Indicates the first Each block is a virtual grayscale.

7. The voltage drop compensation method for an AMOLED display panel according to claim 6, characterized in that, A compensation lookup table is constructed based on the grayscale compensation value of each block, including: The overall brightness value of the AMOLED display panel is used as a parameter; The display brightness values ​​are divided into typical display brightness values ​​and atypical display brightness values; Under typical display brightness values, a compensation lookup table is constructed by collecting the grayscale compensation values ​​of each block under typical display brightness values; For atypical display brightness values, the compensation lookup table for typical display brightness values ​​is fitted by least squares first-order fitting to obtain the compensation lookup table for atypical display brightness values.

8. The voltage drop compensation method for an AMOLED display panel according to claim 7, wherein interpolation is performed on the compensation lookup table on the display driver chip, comprising: Determine whether the grayscale input to the pixel circuit of the AMOLED display panel is a typical grayscale; When the gray level input to the pixel circuit is a typical gray level, the compensation lookup table corresponding to the typical gray level is directly looked up, and bilinear interpolation is performed on the compensation lookup table to obtain the interpolated compensation lookup table. The interpolated compensation lookup table includes gray level compensation values ​​that are equal to the resolution of the AMOLED display panel. When the grayscale input to the pixel circuit is an atypical grayscale, proportional interpolation is required based on the compensation lookup table of the typical grayscale with the smallest difference from the atypical grayscale to obtain the interpolated compensation lookup table of the atypical grayscale. The interpolated compensation lookup table includes grayscale compensation values ​​that are equal to the resolution of the AMOLED display panel.

9. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the voltage drop compensation method for the AMOLED display panel as described in any one of claims 1 to 8.

10. A terminal device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the voltage drop compensation method for the AMOLED display panel as described in any one of claims 1 to 8.

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