Mobile phone display module response compensation method for low temperature working condition

Abstract

This invention relates to the field of mobile phone display control technology, and particularly to a response compensation method for mobile phone display modules under low-temperature conditions. The method acquires panel-side temperature, flexible circuit board-side temperature, display driver chip temperature, ambient temperature, and illumination duration to generate an effective response temperature. It establishes inter-frame grayscale transition states according to display zones and determines the low-temperature response level by combining local motion, refresh rate, and brightness. A response compensation parameter package is generated based on the same low-temperature response level and applied to the display driver link after being constrained by safety boundaries to improve low-temperature ghosting, image retention, color shift, and refresh rate switching anomalies. This invention aims to solve the problems of existing mobile phone display module low-temperature compensation methods relying on a single temperature or a single compensation parameter, which cannot accurately characterize the actual pixel response capability at low temperatures, and cannot simultaneously consider response speed, overshoot, flicker, color shift, power consumption, and temperature rise in low-temperature dynamic display scenarios.

Description

Technical Field This invention relates to the field of mobile phone display control technology, and in particular to a response compensation method for mobile phone display modules under low-temperature conditions. Background Technology When mobile phone display modules operate in low-temperature environments, their display response characteristics deviate significantly from those at room temperature. For LCD modules, low temperatures increase the viscosity of the liquid crystal material and decrease the deflection speed of liquid crystal molecules, leading to prolonged grayscale switching times. This results in problems such as ghosting, image retention, blurred dynamic images, localized screen distortion, and insufficient low-grayscale response. For organic light-emitting diode (OLED) display modules, low temperatures affect the characteristics of thin-film transistors, the efficiency of light-emitting materials, the sub-pixel current build-up process, and color channel consistency, causing changes in the stability of brightness, color coordinates, and gamma curves in low-brightness grayscale, refresh rate switching, and high-brightness display scenarios.

[0001] Existing low-temperature display compensation schemes typically use ambient temperature or the temperature of a single module as the control basis. When the detected temperature is lower than a preset threshold, compensation is achieved by increasing the liquid crystal driving voltage, adjusting the common voltage, calling a temperature compensation lookup table, correcting overdrive grayscale values, or correcting the gamma curve of the OLED display module. These schemes can improve low-temperature display abnormalities to some extent, but they still have shortcomings.

[0002] First, existing solutions mostly rely on a single ambient temperature or a single panel temperature, making it difficult to accurately reflect the actual response status of the mobile phone display module in low-temperature usage scenarios. Even under the same low-temperature environment, the pixel response capabilities of a newly lit cold screen, a display module lit up for several minutes, and high-brightness dynamic images and low-brightness scrolling images are not the same.

[0003] Second, existing LCD low-temperature compensation methods mostly treat temperature-controlled voltage regulation, overdrive compensation, and timing compensation as relatively independent control strategies, lacking a unified modeling of low-temperature response risks. Increasing the driving voltage alone may improve response speed, but it can easily lead to overshoot, flicker, or increased power consumption; increasing the overdrive amount alone may improve grayscale switching speed, but it may also cause reverse ghosting or local brightness fluctuations.

[0004] Third, existing low-temperature compensation methods for OLED displays typically address temperature gamma compensation, digital grayscale compensation, or refresh rate switching compensation separately. They fail to integrate temperature status, inter-frame grayscale shift, refresh rate, brightness level, local motion, and initial voltage into a unified low-temperature response level for coordinated control. Therefore, in scenarios involving low temperature and low brightness, high refresh rate switching, or scrolling displays, brightness jumps, color shifts, low-brightness distortion, or excessively high localized temperatures may still occur.

[0005] Fourth, some compensation schemes place more emphasis on generating the compensation amount, while neglecting to adequately constrain safety boundaries for overshoot, flicker, color shift, power consumption, and temperature rise before applying the compensation parameters. When changes occur in display module batches, refresh rate levels, brightness levels, or image content, over-compensation or compensation mismatch is likely to occur. Summary of the Invention To overcome the above problems, this invention proposes a response compensation method for mobile phone display modules under low-temperature conditions that can effectively solve the above problems.

[0006] The present invention aims to solve the problems of existing low temperature compensation methods for mobile phone display modules, which rely on a single temperature or a single compensation parameter, cannot accurately characterize the actual response capability of pixels at low temperatures, and cannot simultaneously take into account response speed, overshoot, flicker, color shift, power consumption and temperature rise in low temperature dynamic display scenarios.

[0007] The present invention provides a technical solution to solve the above-mentioned technical problems: a method for compensating the response of a mobile phone display module under low-temperature conditions, comprising the following steps: S1. During the control cycle, the panel side temperature, flexible circuit board side temperature, display driver chip temperature, ambient temperature, screen lighting duration and panel temperature change trend of the mobile phone display module are obtained, and an effective response temperature is generated to characterize the actual response capability of the pixels based on the above parameters. S2, divide the current frame image data and the previous frame image data into multiple display partitions, and establish inter-frame grayscale transition state and local motion state for each display partition; S3. Determine the low-temperature response level for each display zone based on the effective response temperature, inter-frame grayscale migration state, local motion state, current refresh rate, and current brightness level. S4. Generate a candidate response compensation parameter package based on the same low-temperature response level; when the mobile phone display module is a liquid crystal display module, the candidate response compensation parameter package includes at least grayscale overdrive parameters and driving voltage correction parameters; when the mobile phone display module is an organic light-emitting diode display module, the candidate response compensation parameter package includes at least gamma equivalent grayscale correction parameters and initial voltage correction parameters. S5, before applying the candidate response compensation parameter package to the display driving link, perform safety boundary constraints on the candidate response compensation parameter package to obtain a response compensation parameter package after constraint correction, wherein the safety boundary includes at least an overshoot boundary and a flicker boundary; S6 updates the constrained response compensation parameter package in stages based on the screen illumination duration and the effective response temperature change trend, and writes the updated response compensation parameter package into the display driver link. Preferably, the effective response temperature is generated according to the following formula: , in, The effective response temperature for the k-th control cycle. This refers to the panel side temperature. Temperature on the flexible circuit board side. To display the temperature of the driver chip, For ambient temperature, The duration of screen illumination. This shows the trend of panel temperature change. To control the cycle, The thermal stability time constant, This is the cold start thermal hysteresis coefficient. This is a temperature trend correction factor. and These are the lowest and highest temperatures to which the model is applicable, respectively. Indicates will Limit to the lower limit and upper limit between.

[0008] Preferably, the panel temperature change trend is determined by the ratio of the panel-side temperature difference between adjacent control cycles to the control cycle, or by the panel-side temperature change between adjacent control cycles after low-pass filtering; and satisfies: ,in, , , , , , .

[0009] Preferably, the number of the plurality of display partitions is 128 to 2048, and the inter-frame grayscale transition intensity of the j-th display partition is generated according to the following formula: , in, Let J be the inter-frame grayscale shift intensity of the j-th display partition. Let j be the set of pixels within the j-th display partition. Let j be the number of pixels in the j-th display partition. Let be the grayscale value of the i-th pixel in the current frame. Let be the grayscale value of the i-th pixel in the previous frame. The maximum grayscale value. For grayscale transition weights, This represents the upper limit of grayscale migration intensity.

[0010] Preferably, the local motion state is obtained by normalizing the block matching displacement, optical flow estimate, or inter-frame pixel difference component; for liquid crystal display modules, the grayscale migration types sensitive to low temperature response include low grayscale to medium grayscale migration, medium grayscale to high grayscale migration, and large grayscale jump migration; for organic light-emitting diode display modules, the grayscale migration types sensitive to low temperature response include low brightness grayscale migration, low brightness to medium brightness migration, and low grayscale migration during refresh rate switching.

[0011] Preferably, the response risk value of the j-th display partition is generated according to the following formula: , in, The response risk value for the j-th display partition. The intensity of grayscale shift between frames. For local motion intensity, Temperature risk factor For refresh rate risk factors, As a brightness risk factor, , , , , Let be the risk weighting coefficient, and satisfy: , Among them, the temperature risk factor is determined by the difference between the effective response temperature and the low temperature compensation start temperature, the refresh rate risk factor is determined by the position of the current refresh rate within the refresh rate range supported by the mobile phone display module, and the brightness risk factor is determined according to the display module type.

[0012] Preferably, when the mobile phone display module is a liquid crystal display module, the brightness risk factor increases as the current brightness level increases; when the mobile phone display module is an organic light-emitting diode display module, the brightness risk factor includes both a low-brightness grayscale distortion risk component and a high-brightness power consumption and temperature rise risk component.

[0013] Preferably, determining the low-temperature response level based on the response risk value includes: when At that time, it was determined to be a no-compensation level; when At that time, it was determined to be a mild compensation level; when At that time, it was determined to be at the moderate compensation level; when At that time, it was determined to be at the severe compensation level; in, .

[0014] Preferably, when the mobile phone display module is a liquid crystal display module, the grayscale overdrive parameters are generated according to the following formula: , in, Let be the overdrive grayscale value of the i-th pixel. The grayscale value of the current frame. It is the difference between the grayscale value of the current frame and the grayscale value of the previous frame. Let be the low-temperature overdrive coefficient of the j-th display partition. It is an overdrive nonlinear index; the low-temperature overdrive coefficient is determined based on the low-temperature response level, response risk value, and cold start state.

[0015] Preferably, the driving voltage correction parameters include at least one of the following: common voltage correction, gate turn-on voltage correction, gate turn-off voltage correction, and source driving voltage correction; the candidate driving voltage correction values ​​for each display partition are generated according to the response risk value and the inter-frame grayscale migration intensity, and are aggregated into the actual applied driving voltage correction value according to the risk weight, area weight, or maximum risk principle.

[0016] Preferably, when the mobile phone display module is an organic light-emitting diode display module, the candidate compensation parameter set for the j-th display zone is generated according to the following relationship: , in, Let j be the set of candidate compensation parameters for the organic light-emitting diode display of the j-th display zone. Let be the gamma equivalent grayscale correction parameter for the c-th color channel. These are the initial voltage correction parameters. The current refresh rate, This is the current brightness level. This refers to the compensation mapping relationship obtained through factory calibration.

[0017] Preferably, the gamma equivalent grayscale correction parameter is used to correct the output grayscale of at least one of the red, green, and blue channels, and the initial voltage correction parameter is used to correct the initial pixel voltage of the OLED display module during low-temperature refresh rate switching or low-brightness scrolling display; both the gamma equivalent grayscale correction parameter and the initial voltage correction parameter are generated in conjunction with the same low-temperature response level.

[0018] Preferably, the safety boundary constraints are implemented through safety boundary projection, which is performed according to the following formula: , in, This is the response compensation parameter package after projection correction. For candidate response compensation parameter package, In response to the compensation parameter package, the first One parameter, For the first The normalization scale of each parameter, For the first Projection weights of each parameter, For a set of safety constraints.

[0019] Preferably, the set of safety constraints includes at least an overshoot boundary and a scintillation boundary; wherein the overshoot boundary is determined based on the deviation of the predicted brightness from the target brightness, and the scintillation boundary is determined based on the residual fluctuation of the predicted brightness relative to the target brightness.

[0020] Preferably, the set of safety constraints further includes at least one of a color deviation boundary, a power consumption boundary, and a module temperature rise boundary; wherein the color deviation boundary is determined based on the deviation between the target color coordinates and the predicted color coordinates, the power consumption boundary is determined based on the driving voltage, current, and backlight power consumption or light emission power consumption, and the module temperature rise boundary is determined based on the current module temperature, the predicted power consumption, and the heat dissipation coefficient.

[0021] Preferably, the phased update includes a cold start phase, a transition phase, and a stable low temperature phase; in the cold start phase, the compensation intensity of grayscale overdrive parameters, drive voltage correction parameters, gamma equivalent grayscale correction parameters, or initial voltage correction parameters is increased; in the transition phase, the compensation intensity is gradually reduced as the screen illumination duration increases and the effective response temperature rises; in the stable low temperature phase, only non-safety-critical compensation parameters are updated within the boundary.

[0022] Preferably, when the screen illumination duration does not exceed 60 seconds and the effective response temperature is lower than the low-temperature compensation start-up temperature, the system enters the cold start stage; when the screen illumination duration is greater than 60 seconds but not more than 300 seconds and the effective response temperature shows an upward trend, the system enters the transition stage; when the screen illumination duration is greater than 300 seconds and the effective response temperature change is less than a preset change threshold, the system enters the stable low-temperature stage.

[0023] Preferably, the mobile phone display module response compensation method for low-temperature operating conditions further includes a factory calibration step: At temperatures of at least 25°C, 0°C, -5°C, -10°C, -15°C, and -20°C, combined sampling was performed on refresh rate levels of at least 60Hz, 90Hz, and 120Hz, and brightness levels of at least 10nit, 50nit, 200nit, and 600nit. Under each combination of sampling conditions, the measurement includes at least three of the following indicators: response time, overshoot, flicker, color shift, power consumption, and temperature rise. The model parameter set is obtained by minimizing the normalization error between the measured index and the predicted index. The model parameter set includes at least the effective response temperature model parameters, risk weight parameters, level thresholds, liquid crystal display compensation parameters, organic light-emitting diode display compensation parameters, and safety boundary parameters.

[0024] Preferably, the model parameter set is associated with the display module model, supplier code, display driver chip version, refresh rate level, and brightness level, and stored in the internal storage area of ​​the display driver chip, the system security partition, or the protected configuration area; during subsequent operation, only non-safety critical compensation parameters are allowed to be updated within the factory calibration boundary.

[0025] The present invention also provides a mobile phone display module response compensation device for low-temperature operating conditions, comprising: The temperature acquisition module is used to acquire the panel side temperature, flexible circuit board side temperature, display driver chip temperature, ambient temperature, screen lighting duration, and panel temperature change trend. The risk modeling module is used to calculate the effective response temperature, inter-frame grayscale transition state, local motion state, and low-temperature response level. The compensation generation module is used to generate candidate response compensation parameter packages based on the same low temperature response level. The safety constraint module is used to perform safety boundary constraints on the candidate response compensation parameter package, which include at least overshoot boundaries and scintillation boundaries. The phased update module is used to perform phased updates based on the screen illumination duration and the effective response temperature change trend. The driver application module is used to write the updated response compensation parameter package into the display driver link; The temperature acquisition module is connected to the risk modeling module, the risk modeling module is connected to the compensation generation module, the compensation generation module is connected to the safety constraint module, the safety constraint module is connected to the stage update module, the stage update module is connected to the drive application module, and the risk modeling module is connected to the stage update module.

[0026] The device is used to perform the method described in this invention.

[0027] The present invention also provides a mobile terminal, including a processor, a memory, a temperature detection unit, a display driver unit, and a mobile phone display module. The memory stores a computer program, which, when executed by the processor, implements the method described in the present invention.

[0028] The present invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the method described in the present invention.

[0029] Compared with the prior art, the mobile phone display module response compensation method for low-temperature operating conditions of the present invention has the following beneficial effects: 1. This invention generates an effective response temperature by measuring panel-side temperature, flexible circuit board-side temperature, display driver chip temperature, ambient temperature, screen illumination duration, and temperature change trend. It no longer relies on a single temperature reading and can more accurately characterize the actual response capability of pixels at low temperatures.

[0030] 2. This invention establishes inter-frame grayscale migration state and local motion state according to display partitions, enabling low temperature compensation to respond to risk identification in local areas prone to ghosting, afterimages, low brightness distortion, or abnormal refresh rate switching.

[0031] 3. This invention generates compensation parameter packages in a coordinated manner at the same low-temperature response level. For liquid crystal display paths, grayscale overdrive parameters and driving voltage correction parameters are constrained simultaneously at the same level; for organic light-emitting diode display paths, gamma equivalent grayscale correction parameters and initial voltage correction parameters are constrained simultaneously at the same level, thereby reducing compensation mismatch caused by multiple compensation strategies operating independently.

[0032] 4. The present invention performs safety boundary constraints before applying compensation parameters, which at least simultaneously satisfies the overshoot boundary and the scintillation boundary, and can further satisfy the color shift, power consumption and predicted temperature rise boundaries, thereby reducing the risk of overcompensation.

[0033] 5. This invention updates the cold start stage, transition stage and stable low temperature stage in stages based on the screen lighting duration and the effective response temperature change trend, so that there is sufficient compensation intensity in the low temperature lighting stage, and the compensation intensity is reduced after the module self-heats up to avoid continuous overcompensation. Attached Figure Description Figure 1 This is a flowchart of the mobile phone display module response compensation method for low-temperature operating conditions according to the present invention. Figure 2 This is a structural block diagram of the mobile phone display module response compensation device for low-temperature operating conditions according to the present invention. Detailed Implementation To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0034] It should be noted that in the embodiments of the present invention, all directional indications (such as up, down, left, right, front, back, etc.) are limited to relative positions on the specified view, rather than absolute positions.

[0035] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0036] Please see Figure 1 and Figure 2 The response compensation method for mobile phone display modules under low-temperature operating conditions of the present invention is applicable to smartphones, foldable phones, tablet mobile terminals, or portable terminals with mobile phone display module structures. The mobile phone display module can be a liquid crystal display module or an organic light-emitting diode display module, wherein the organic light-emitting diode display module includes OLED display modules or AMOLED display modules.

[0037] The mobile phone display module is equipped with temperature detection points on the panel side, the flexible circuit board side, and the display driver chip side. Ambient temperature can be provided by a whole-device temperature sensor, a casing temperature sensor, or a system temperature estimation unit. The screen illumination duration is recorded by a system display session timer or a power management unit.

[0038] When the ambient temperature, panel side temperature, or effective response temperature is detected to be lower than the preset low-temperature compensation start temperature, the low-temperature response compensation process of this embodiment is initiated. The low-temperature compensation start temperature can be set according to the display module type, liquid crystal material type, OLED device type, supplier calibration results, or overall system reliability requirements, such as 0℃, -5℃, or other temperature values.

[0039] The control period Δt can be 1 to 8 frames, preferably 2 or 4 frames. Within each control period, the cryogenic response risk calculation, compensation parameter generation, safety boundary constraints, and parameter updates are performed once.

[0040] In this embodiment, low-temperature response compensation is not performed by directly looking up a table based on a single temperature value. Instead, an effective response temperature is first generated, and then a low-temperature response level is established by combining inter-frame grayscale transition state, local motion state, refresh rate, and brightness level. At least two types of compensation parameters are generated in conjunction with the same low-temperature response level. This processing method can reduce the risk of inconsistency between different compensation strategies.

[0041] In low-temperature environments, the actual response state of a display module is not equivalent to a single ambient temperature reading. For liquid crystal display modules, the response of liquid crystal molecules is related to the actual thermal state of the liquid crystal layer, the viscoelasticity of the material, and the self-heating process after lighting. For organic light-emitting diode display modules, at low temperatures, thin-film transistors, current build-up, luminous efficiency, and differences in sub-pixel channels all affect brightness and color stability.

[0042] Therefore, this embodiment defines the effective response temperature. This is used to characterize the actual response capability of a pixel. The effective response temperature is generated according to the following formula: , in, This refers to the panel side temperature. Temperature on the flexible circuit board side. To display the temperature of the driver chip, For ambient temperature, The duration of screen illumination. The thermal stability time constant, This is the cold start thermal hysteresis coefficient. This is the temperature trend correction factor.

[0043] The panel temperature change trend can be determined by the ratio of the panel-side temperature difference between adjacent control cycles to the control cycle, or it can be obtained after low-pass filtering. In one embodiment, the parameter range is as follows: , And satisfy: , In the formula, the first four terms are used to integrate multiple temperature sources; the exponential term reflects the thermal hysteresis caused by the inconsistency between the ambient temperature and the panel temperature during the cold start phase; and the last term reflects the self-heating trend of the panel after the screen is turned on. When the phone is first turned on and the ambient temperature is low, the thermal hysteresis term makes the effective response temperature lower than the single panel temperature reading; as the duration of illumination increases and the panel temperature continues to rise, the temperature trend term makes the effective response temperature gradually decrease, thereby avoiding further strengthening compensation.

[0044] In this embodiment, the current frame and the previous frame are divided into multiple display partitions. The number of display partitions can be from 128 to 2048, for example, divided into 8×16, 16×32, or 32×64 display partitions.

[0045] Establish the inter-frame grayscale transition intensity for the j-th display partition: , in, Let J be the inter-frame grayscale shift intensity of the j-th display partition. Let j be the set of pixels within the j-th display partition. Let j be the number of pixels in the j-th display partition. Let be the grayscale value of the i-th pixel in the current frame. Let be the grayscale value of the i-th pixel in the previous frame. The maximum grayscale value. This represents the grayscale transition weight.

[0046] For LCD modules, low-temperature-responsive migration types include low-grayscale to medium-grayscale migration, medium-grayscale to high-grayscale migration, large-amplitude forward jump migration, and large-amplitude reverse jump migration. For OLED modules, low-temperature-responsive migration types include low-brightness grayscale migration, low-brightness to medium-brightness migration, grayscale migration in low average image brightness scrolling scenarios, and low-grayscale migration during refresh rate switching.

[0047] In one implementation, the weight of normal grayscale migration is 1.00, the weight of low-temperature sensitive migration is 1.10 to 1.25, and the weight of low-brightness grayscale migration within three consecutive frames before and after refresh rate switching is 1.15 to 1.35.

[0048] Local motion states can be determined by block-matching displacement, optical flow estimation, or inter-frame pixel difference. The greater the intensity of local motion, the more easily the display area will expose ghosting, image retention, or lag issues at low temperatures.

[0049] After obtaining the effective response temperature, inter-frame grayscale transition status, and local motion status, a response risk value is further generated by combining the refresh rate and brightness level: , in, The response risk value for the j-th display partition. The intensity of grayscale shift between frames. For local motion intensity, The temperature risk factor is determined by the difference between the effective response temperature and the low-temperature compensation start-up temperature. The refresh rate risk factor is determined by the position of the current refresh rate within the supported refresh rate range. This is a brightness risk factor.

[0050] For LCD modules, the brightness risk factor increases with the current brightness level to reflect the more perceptible response lag under high-brightness dynamic display conditions. For OLED modules, the brightness risk factor includes both low-brightness grayscale distortion risk and high-brightness power consumption and temperature rise risk to reflect both low-temperature low-brightness grayscale distortion and high-brightness power consumption constraints.

[0051] The low-temperature response level is determined based on the response risk value. When When, it is determined to be a no-compensation level; when When, it is determined to be a mild compensation level; when When, it is determined to be at the moderate compensation level; when At that time, it was determined to be at the level of severe compensation.

[0052] In one implementation: In this way, the low-temperature response level is no longer determined solely by temperature, but rather by a combination of factors including the degree of low temperature, grayscale shift, localized motion, refresh rate, and brightness. Therefore, different compensation strategies can be applied to low-temperature static images, high-refresh-rate scrolling images, low-brightness grayscale change images, and high-brightness dynamic images.

[0053] When the mobile phone display module is an LCD display module, the candidate response compensation parameter package includes at least grayscale overdrive parameters and drive voltage correction parameters.

[0054] The grayscale overdrive parameters are generated according to the following formula: , in, Let be the overdrive grayscale value of the i-th pixel. The grayscale value of the current frame. It is the difference between the grayscale value of the current frame and the grayscale value of the previous frame. Let be the low-temperature overdrive coefficient of the j-th display partition. It is an overdrive nonlinear index; the low-temperature overdrive coefficient is determined based on the low-temperature response level, response risk value, and cold start state.

[0055] The driving voltage correction parameters may include at least one of the following: common voltage correction, gate turn-on voltage correction, gate turn-off voltage correction, and source driving voltage correction. Candidate driving voltage correction values ​​for each display zone can be generated based on response risk values ​​and inter-frame grayscale migration intensity, and then aggregated according to risk weight, area weight, or maximum risk principle to form the actual applied driving voltage correction value.

[0056] For example, the common voltage correction range can be [ The gate turn-on voltage correction range is [0, 2.5]V; the absolute correction range for the gate turn-off voltage is [0, 1.5]V. These ranges can be calibrated according to different display module models, driver chip specifications, and reliability requirements.

[0057] The core of this liquid crystal display path does not lie in simply increasing the driving voltage or the overdrive grayscale value, but in the fact that both the grayscale overdrive parameter and the driving voltage correction parameter are generated by the same low-temperature response level and are subject to safety boundary constraints before being applied.

[0058] When the mobile phone display module is an organic light-emitting diode display module, the candidate response compensation parameter package shall include at least the gamma equivalent grayscale correction parameter and the initial voltage correction parameter.

[0059] In one implementation, the set of candidate compensation parameters for the j-th display partition is generated according to the following relationship: , in, Let j be the set of candidate compensation parameters for the organic light-emitting diode display of the j-th display zone. Let be the gamma equivalent grayscale correction parameter for the c-th color channel. These are the initial voltage correction parameters. The current refresh rate, This is the current brightness level. This refers to the compensation mapping relationship obtained through factory calibration.

[0060] The gamma equivalent grayscale correction parameter is used to correct the output grayscale of at least one of the red, green, and blue channels. The correction coefficients for different color channels can be different at low temperatures to compensate for differences in color channel response caused by low temperatures.

[0061] The initial voltage correction parameter is used to correct the initial pixel voltage of the OLED display module during low-temperature refresh rate switching or low-brightness scrolling display. At low temperatures and during 60Hz to 120Hz, 90Hz to 120Hz, or low-brightness scrolling display transitions, the initial voltage correction parameter and the gamma equivalent grayscale correction parameter are generated in conjunction with the same low-temperature response level, thereby improving brightness jumps, low-brightness distortion, and color shift caused by refresh rate switching.

[0062] To avoid overcompensation, this embodiment performs safety boundary constraints before applying the candidate response compensation parameter package. These safety boundary constraints can be implemented through safety boundary projection.

[0063] Let the candidate response compensation parameter package be denoted as The response compensation parameter package after projection correction is denoted as ,but: , in, In response to the compensation parameter package, the first One parameter, For the first The normalization scale of each parameter, For the first Projection weights of each parameter, This is a set of safety constraints. By normalizing the scale, projection bias caused by direct comparison of parameters with different dimensions such as grayscale, voltage, current, and time series can be avoided.

[0064] The set of safety constraints includes at least an overshoot boundary and a flicker boundary. The overshoot boundary is determined based on the deviation of the predicted brightness from the target brightness, and the flicker boundary is determined based on the residual fluctuation of the predicted brightness relative to the target brightness. Preferably, the set of safety constraints further includes at least one of a color shift boundary, a power consumption boundary, and a module temperature rise boundary.

[0065] The color deviation boundary can be determined based on the deviation between the target color coordinates and the predicted color coordinates. The power consumption boundary can be determined based on the driving voltage, current, and backlight power consumption or light emission power consumption. The module temperature rise boundary can be determined based on the current module temperature, predicted power consumption, and heat dissipation coefficient.

[0066] In computationally limited implementations, safety boundary constraints can be approximated by item-by-item pruning. This involves sequentially pruning the grayscale overdrive coefficient, drive voltage correction, gamma equivalent grayscale correction, and initial voltage correction, and re-verifying the overshoot and flicker boundaries after each pruning until the safety boundary requirements are met.

[0067] Under low-temperature conditions, the response state of the mobile phone display module when it is first turned on differs from its response state after continuous illumination. Therefore, this embodiment divides the update of the response compensation parameter package into a cold start stage, a transition stage, and a stable low-temperature stage.

[0068] When the screen is on for no more than 60 seconds and the effective response temperature is lower than the low-temperature compensation start-up temperature, it enters the cold start phase. At this time, the compensation intensity of grayscale overdrive parameters, drive voltage correction parameters, gamma equivalent grayscale correction parameters, or initial voltage correction parameters is increased to improve ghosting, afterimages, low-brightness distortion, and abnormal refresh rate switching under the low-temperature cold screen that has just been turned on.

[0069] When the screen is on for more than 60 seconds but no more than 300 seconds, and the effective response temperature shows an upward trend, it enters the transition phase. At this time, the compensation intensity gradually decreases as the panel heats up, to avoid overshoot, flicker, color deviation, increased power consumption, or excessive local temperature rise caused by continuous high compensation.

[0070] When the screen remains on for more than 300 seconds and the effective response temperature change is less than the preset threshold, the system enters a stable low-temperature phase. At this point, basic compensation is retained, and only non-safety-critical compensation parameters are allowed to be slightly updated within the factory calibration limits.

[0071] The non-safety-critical compensation parameters may include a small correction amount for the grayscale overdrive coefficient, a gamma equivalent grayscale correction mapping index, and local compensation weights for low-risk zones. The safety-critical parameters may include the upper limit of the driving voltage, the upper and lower limits of the initial voltage, the upper limit of the luminous current, the temperature rise safety threshold, and the overshoot boundary.

[0072] To ensure the feasibility of this invention and the compatibility between different modules, this embodiment provides a factory calibration process.

[0073] The calibrated temperature ranges must include at least 25℃, 0℃, -5℃, -10℃, -15℃, and -20℃. The refresh rate levels must include at least 60Hz, 90Hz, and 120Hz. The brightness levels must include at least 10nit, 50nit, 200nit, and 600nit.

[0074] The calibration patterns include all-white static images, low average image brightness scrolling patterns, grayscale bars, checkerboard patterns, text scrolling patterns, and preset grayscale transition patterns. Grayscale transition types include at least 0 to 32, 32 to 128, 128 to 255, 255 to 64, 64 to 192, and 192 to 32.

[0075] The calibration parameters should include at least three of the following: response time, overshoot, flicker, color deviation, power consumption, and temperature rise. For liquid crystal display modules, it is preferable to measure response time, overshoot, and flicker; for organic light-emitting diode display modules, it is preferable to measure low-brightness error, color deviation, brightness fluctuation during refresh rate switching, power consumption, and temperature rise.

[0076] The model parameter set is obtained by minimizing the normalization error between the measured and predicted indicators. This model parameter set may include effective response temperature model parameters, risk weight parameters, level thresholds, liquid crystal display overdrive parameters, liquid crystal display voltage correction parameters, organic light-emitting diode display gamma equivalent grayscale correction parameters, initial voltage correction parameters, and safety boundary parameters.

[0077] After calibration, the parameter set is associated with the display module model, supplier code, driver chip version, refresh rate level, and brightness level, and stored in the internal storage area of ​​the display driver chip, the system security partition, or the protected configuration area.

[0078] During subsequent operation, only non-safety-critical compensation parameters are allowed to be updated within the preset range of the factory calibration values. It is prohibited to exceed the overshoot boundary, flicker boundary, color deviation boundary, power consumption boundary, and temperature rise boundary.

[0079] In one embodiment of the liquid crystal display, the parameter values ​​are as follows:

[0080] .

[0081] Under conditions of -15℃, 120Hz, 500nit, and 64 to 192 grayscale migration, the response time without compensation is approximately 41.8ms, the response time after single-temperature voltage regulation compensation is approximately 31.2ms, and the response time after compensation according to the present invention is approximately 23.8ms. The overshoot evaluation value of single-temperature voltage regulation compensation is approximately 0.061, and the overshoot evaluation value of the present invention after safety boundary constraints is approximately 0.029, which can simultaneously improve response time and overshoot risk.

[0082] In one embodiment of an organic light-emitting diode display, under conditions of -15°C, switching between 60Hz and 120Hz, and low brightness of 50nit, the brightness change evaluation value without compensation is approximately 6.8 visually discernible units, and approximately 3.7 after gamma compensation alone. After compensation by gamma equivalent grayscale correction and initial voltage linkage, the value is approximately 0.8. The color shift without compensation is approximately 0.011, and after compensation by this invention, it is approximately 0.003. At the same time, the predicted temperature rise is below the safety threshold.

[0083] The example data above is used to illustrate the technical effects of the present invention. In actual products, the parameters can be recalibrated according to the specific display module model, supplier batch, and driver chip specifications.

[0084] This embodiment provides a mobile phone display module response compensation device for low-temperature operating conditions, including a temperature acquisition module, a risk modeling module, a compensation generation module, a safety constraint module, a stage update module, and a drive application module.

[0085] The temperature acquisition module is used to acquire panel-side temperature, flexible circuit board-side temperature, display driver chip temperature, ambient temperature, screen illumination duration, and panel temperature change trend.

[0086] The risk modeling module is used to calculate the effective response temperature, inter-frame grayscale transition state, local motion state, and low-temperature response level.

[0087] The compensation generation module is used to generate candidate response compensation parameter packages based on the same low-temperature response level.

[0088] The safety constraint module is used to apply safety boundary constraints to the candidate response compensation parameter package.

[0089] The phased update module is used to implement phased updates, namely the cold start phase, the transition phase, and the stable low temperature phase, based on the screen lighting duration and the effective response temperature change trend.

[0090] The driver application module is used to write the updated response compensation parameter package into the display driver link.

[0091] This embodiment also provides a mobile terminal, including a processor, a memory, a temperature detection unit, a display driver unit, and a mobile phone display module. The memory stores a computer program, which, when executed by the processor, implements the above-described method.

[0092] This embodiment also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method.

[0093] The temperature acquisition, frame buffer reading, partition grayscale migration calculation, local motion analysis, refresh rate level acquisition, brightness level acquisition, compensation parameter generation, safety boundary clipping, and display driver register writing involved in this invention can all be implemented based on existing mobile application processors, display coprocessors, display driver chips, timing controllers, and system software.

[0094] For liquid crystal display modules, the present invention can output corrected grayscale data through an application processor or display driver chip, and adjust the common voltage, gate turn-on voltage, gate turn-off voltage, source drive voltage or precharge timing through the display driver chip register.

[0095] For organic light-emitting diode display modules, the present invention can output corrected gamma equivalent grayscale data, color channel grayscale data, initial voltage parameters, and luminous current limiting parameters through a display processing unit or a display driver chip.

[0096] The weighting coefficients, thresholds, and boundary values ​​involved in each formula in this invention can all be obtained through factory calibration, module specification parameters, reliability testing, or whole-machine display debugging, without relying on unrealizable hardware structures or unverifiable algorithm conditions.

[0097] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any modifications, equivalent substitutions and improvements made within the concept of the present invention should be included within the patent protection scope of the present invention.

Claims

1. A response compensation method for mobile phone display modules under low-temperature operating conditions, characterized in that, Includes the following steps: S1. During the control cycle, the panel side temperature, flexible circuit board side temperature, display driver chip temperature, ambient temperature, screen lighting duration and panel temperature change trend of the mobile phone display module are obtained, and an effective response temperature is generated to characterize the actual response capability of the pixels based on the above parameters. S2, divide the current frame image data and the previous frame image data into multiple display partitions, and establish inter-frame grayscale transition state and local motion state for each display partition; S3. Determine the low-temperature response level for each display zone based on the effective response temperature, inter-frame grayscale migration state, local motion state, current refresh rate, and current brightness level. S4. Generate a candidate response compensation parameter package based on the same low-temperature response level; when the mobile phone display module is a liquid crystal display module, the candidate response compensation parameter package includes at least grayscale overdrive parameters and driving voltage correction parameters; when the mobile phone display module is an organic light-emitting diode display module, the candidate response compensation parameter package includes at least gamma equivalent grayscale correction parameters and initial voltage correction parameters. S5, before applying the candidate response compensation parameter package to the display driving link, perform safety boundary constraints on the candidate response compensation parameter package to obtain a response compensation parameter package after constraint correction, wherein the safety boundary includes at least an overshoot boundary and a flicker boundary; S6 updates the constrained response compensation parameter package in stages based on the screen illumination duration and the effective response temperature change trend, and writes the updated response compensation parameter package into the display driver link.

2. The response compensation method for mobile phone display modules under low-temperature conditions as described in claim 1, characterized in that, The effective response temperature is generated according to the following formula: ， in, The effective response temperature for the k-th control cycle. This refers to the panel side temperature. Temperature on the flexible circuit board side. To display the temperature of the driver chip, For ambient temperature, The duration of screen illumination. This shows the trend of panel temperature change. To control the cycle, The thermal stability time constant, This is the cold start thermal hysteresis coefficient. This is a temperature trend correction factor. and These are the lowest and highest temperatures to which the model is applicable, respectively. Indicates will Limit to the lower limit and upper limit between.

3. The response compensation method for mobile phone display modules under low-temperature conditions as described in claim 2, characterized in that, The trend of panel temperature change is determined by the ratio of the panel-side temperature difference between adjacent control cycles to the control cycle, or by the panel-side temperature change between adjacent control cycles after low-pass filtering; and satisfies: ,in, , , , , , .

4. The response compensation method for mobile phone display modules under low-temperature conditions as described in claim 1, characterized in that, The number of the plurality of display partitions is between 128 and 2048, and the inter-frame grayscale transition intensity of the j-th display partition is generated according to the following formula: ， in, Let J be the inter-frame grayscale shift intensity of the j-th display partition. Let j be the set of pixels within the j-th display partition. Let j be the number of pixels in the j-th display partition. Let be the grayscale value of the i-th pixel in the current frame. Let be the grayscale value of the i-th pixel in the previous frame. The maximum grayscale value. For grayscale transition weights, This represents the upper limit of grayscale migration intensity.

5. The response compensation method for mobile phone display modules under low-temperature conditions as described in claim 4, characterized in that, The local motion state is obtained by normalizing the block matching displacement, optical flow estimate, or inter-frame pixel difference component; for liquid crystal display modules, the grayscale migration types that are sensitive to low temperature response include low grayscale to medium grayscale migration, medium grayscale to high grayscale migration, and large grayscale jump migration. For organic light-emitting diode display modules, grayscale migration types that are sensitive to low-temperature response include low-brightness grayscale migration, low-brightness to medium-brightness migration, and low-grayscale migration during refresh rate switching.

6. The response compensation method for mobile phone display modules under low-temperature conditions as described in claim 1, characterized in that, The response risk value of the j-th display partition is generated according to the following formula: ， in, The response risk value for the j-th display partition. The intensity of grayscale shift between frames. For local motion intensity, Temperature risk factor For refresh rate risk factors, As a brightness risk factor, , , , , Let be the risk weighting coefficient, and satisfy: ， Among them, the temperature risk factor is determined by the difference between the effective response temperature and the low temperature compensation start temperature, the refresh rate risk factor is determined by the position of the current refresh rate within the refresh rate range supported by the mobile phone display module, and the brightness risk factor is determined according to the display module type.

7. The mobile phone display module response compensation method for low-temperature operating conditions as described in claim 6, characterized in that, When the mobile phone display module is a liquid crystal display module, the brightness risk factor increases as the current brightness level increases; when the mobile phone display module is an organic light-emitting diode display module, the brightness risk factor includes both the low-brightness grayscale distortion risk component and the high-brightness power consumption and temperature rise risk component.

8. The mobile phone display module response compensation method for low-temperature operating conditions as described in claim 6, characterized in that, The cryogenic response level is determined based on the aforementioned response risk value, including: when At that time, it was determined to be a no-compensation level; when At that time, it was determined to be a mild compensation level; when At that time, it was determined to be at the moderate compensation level; when At that time, it was determined to be at the severe compensation level; in, .

9. The response compensation method for mobile phone display modules under low-temperature conditions as described in any one of claims 1-8, characterized in that, When the mobile phone display module is a liquid crystal display module, the grayscale overdrive parameters are generated according to the following formula: ， in, Let be the overdrive grayscale value of the i-th pixel. The grayscale value of the current frame. It is the difference between the grayscale value of the current frame and the grayscale value of the previous frame. Let be the low-temperature overdrive coefficient of the j-th display partition. It is an overdrive nonlinear index; the low-temperature overdrive coefficient is determined based on the low-temperature response level, response risk value, and cold start state.

10. The response compensation method for mobile phone display modules under low-temperature conditions as described in claim 9, characterized in that, The driving voltage correction parameters include at least one of the following: common voltage correction, gate turn-on voltage correction, gate turn-off voltage correction, and source driving voltage correction. The candidate driving voltage correction values ​​for each display partition are generated according to the response risk value and the inter-frame grayscale migration intensity, and are aggregated into the actual applied driving voltage correction value according to the risk weight, area weight, or maximum risk principle.

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