A PWM dimming method and device for backlight brightness

Abstract

The application provides a PWM dimming method and device for backlight brightness, which comprises the following steps: constructing a brightness reference model matching the visual perception characteristics of human eyes; respectively measuring the luminous brightness curve of each monochromatic light in the three primary color lights of a display panel, and determining the PWM dimming control parameter of each monochromatic light at each gray scale; fusing the luminous brightness curve of each monochromatic light based on a preset light intensity ratio to obtain a fused curve, and correcting the fused curve by using the brightness reference model; reversely deducing the target dimming parameter corresponding to the three primary color lights at each brightness adjustment level of the display panel based on the corrected fused curve and the PWM dimming control parameter; establishing the mapping relationship between the brightness adjustment level and the target dimming control parameter, and performing PWM dimming by using the mapping relationship. By using the PWM dimming method and device for backlight brightness, the problem of obvious dimming step feeling and poor visual comfort is solved.

Description

Technical Field

[0001] This application relates to the field of display technology, and more specifically, to a PWM dimming method and apparatus for backlight brightness. Background Technology

[0002] With the increasing popularity of LCD panels, users have placed higher demands on dimming uniformity, color accuracy, and eye protection. LCD panels rely on backlight modules for illumination, and their dimming effect directly affects display quality and visual experience. Currently, the mainstream backlight adjustment method usually adopts direct current (DC) dimming.

[0003] However, existing DC dimming methods do not match the human eye's perception of brightness, and are prone to problems such as obvious dimming steps and abrupt transitions in low-brightness ranges, resulting in poor visual comfort and difficulty in achieving a smooth and natural brightness adjustment effect. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a PWM dimming method and apparatus for backlight brightness to overcome at least one of the above-mentioned defects.

[0005] In a first aspect, embodiments of this application provide a PWM dimming method for backlight brightness, including: Construct a brightness reference model that matches the visual perception characteristics of the human eye; The luminance curves of each monochromatic light in the three primary colors of the display panel are measured respectively, and the PWM dimming control parameters of each monochromatic light at each gray level are determined. The luminance curves are used to characterize the correspondence between gray level and luminance under the monochromatic light. The luminance curves of each monochromatic light are fused based on a preset light intensity ratio to obtain a fusion curve, and the fusion curve is corrected using a luminance reference model. Based on the corrected fusion curve and PWM dimming control parameters, the target dimming parameters corresponding to the three primary colors of light at each brightness adjustment level of the display panel are derived in reverse. Establish a mapping relationship between brightness adjustment levels and target dimming control parameters, and use the mapping relationship to perform PWM dimming of the display panel.

[0006] In an optional implementation, the step of reversely deriving the dimming parameters corresponding to the three primary colors of light at each brightness adjustment level of the display panel based on the corrected fusion curve and PWM dimming control parameters includes: for each brightness adjustment level, determining the target total brightness corresponding to the brightness adjustment level according to the corrected fusion curve; dividing the target total brightness into the target brightness of each monochromatic light according to the preset light intensity ratio; and reversely deriving the target dimming parameters corresponding to the target brightness of each monochromatic light based on the determined PWM dimming control parameters of each monochromatic light at each grayscale.

[0007] In an optional implementation, the step of fusing the luminance curves of each monochromatic light based on a preset light intensity ratio to obtain a fusion curve includes: weighting and fusing the luminance curves corresponding to the three primary colors of light according to the preset light intensity ratio to obtain a fusion curve.

[0008] In an optional implementation, the step of measuring the luminance curve of each monochromatic light in the three primary colors of the display panel includes: for the target monochromatic light, driving the display panel to release the target monochromatic light separately, and turning off the other monochromatic lights except for the target monochromatic light; collecting the luminance of the target monochromatic light at different gray levels to generate the luminance curve of the target monochromatic light.

[0009] In an optional implementation, the luminance reference model is that the perceived luminance level is equal to the sum of the product of the scaling factor and the natural logarithm of the physical luminance intensity and the perception constant.

[0010] In an optional implementation, the perception constant is determined by: determining the hardware residual brightness of the display panel at black level; and determining the perception constant based on the hardware residual brightness.

[0011] In an optional implementation, the scaling factor is determined by: determining the maximum display brightness of the display panel; and determining the scaling factor based on the difference between the maximum display brightness and the hardware residual brightness.

[0012] In an optional implementation, the minimum display brightness of the display panel is greater than the product of the maximum display brightness and a preset ratio value.

[0013] In an optional implementation, when the minimum display brightness of the display panel is greater than the product of the maximum display brightness and a preset ratio, the preset intensity ratio of red light in the three primary colors is greater than 20%, and the preset intensity ratio of blue light is greater than 8%.

[0014] Secondly, embodiments of this application also provide a PWM dimming device for backlight brightness, the device comprising: The model building module is used to build a brightness reference model that matches the visual perception characteristics of the human eye; The curve measurement module is used to measure the luminance curve of each monochromatic light in the three primary colors of the display panel, and to determine the PWM dimming control parameters of each monochromatic light at each gray level. The luminance curve is used to characterize the correspondence between gray level and luminance under the monochromatic light. The fusion and correction module is used to fuse the luminance curves of each monochromatic light based on a preset light intensity ratio to obtain a fusion curve, and to correct the fusion curve using the luminance reference model. The parameter determination module is used to reverse deduce the target dimming parameters corresponding to the three primary colors of light at each brightness adjustment level of the display panel based on the corrected fusion curve and the PWM dimming control parameters. The brightness adjustment module is used to establish a mapping relationship between the brightness adjustment level and the target dimming control parameters, and to perform PWM dimming of the display panel using the mapping relationship.

[0015] The embodiments of this application bring the following beneficial effects: The PWM dimming method and apparatus for backlight brightness provided in this application can optimize the dimming curve based on the human eye's brightness perception characteristics, making the brightness adjustment smooth and uniform, and maintaining a constant ratio of the three primary color light intensity at all levels, effectively improving the dimming comfort and smoothness. Compared with the existing PWM dimming method for backlight brightness, it solves the problems of obvious dimming steps and poor visual comfort.

[0016] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A flowchart of the PWM dimming method for backlight brightness provided in an embodiment of this application is shown; Figure 2 A flowchart illustrating the steps for determining the target dimming parameters provided in an embodiment of this application is shown; Figure 3 A schematic diagram of the backlight brightness PWM dimming device provided in the embodiments of this application is shown; Figure 4 A schematic diagram of the structure of the electronic device provided in the embodiments of this application is shown. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. Based on the embodiments of this application, every other embodiment obtained by those skilled in the art without inventive effort falls within the scope of protection of this application.

[0020] To facilitate understanding of this embodiment, the following describes each of the exemplary steps provided in this embodiment by taking the PWM dimming method for backlight brightness provided in this application embodiment as an example of its application to a terminal device.

[0021] Please see Figure 1 , Figure 1 This is a flowchart illustrating a PWM dimming method for backlight brightness provided in an embodiment of this application. Figure 1 As shown in the embodiments of this application, the PWM dimming method for backlight brightness includes: Step S101: Construct a brightness reference model that matches the visual perception characteristics of the human eye.

[0022] Fechner's law reveals the relationship between subjective brightness perception and physical brightness. A brightness reference model can be constructed based on Fechner's law to conform to the actual visual perception law of the human eye, thereby avoiding the perception mismatch problem caused by traditional dimming methods from the root.

[0023] The luminance reference model states that the perceived luminance level equals the sum of the product of the scaling factor and the natural logarithm of the physical luminance intensity, plus the perception constant. Here, the subjective perceived luminance level is denoted as S, the scaling factor as k, the physical luminance intensity as I, and the perception constant as C. The mathematical expression for the luminance reference model is: .

[0024] The perceived brightness level is within the normalized value range of 0 to 100, corresponding to the 0 to 100 brightness adjustment levels of the display panel. When S is 0, it corresponds to pure black as perceived by the human eye, and when S is 100, it corresponds to the maximum brightness of the panel as perceived by the human eye. The scaling factor is used to adjust the mapping range between perceived brightness and physical brightness. The physical brightness intensity is the actual physical brightness intensity of the display panel backlight, measured in nits. The perception constant is used to offset the hardware residual brightness at the black level of the LCD panel.

[0025] In one embodiment, when determining the perception constant, the hardware residual brightness of the display panel at the black level can be determined first, and then the perception constant can be determined based on the hardware residual brightness.

[0026] For example: A brightness detection device is used to measure the residual hardware brightness of the display panel in a black-level state, that is, the actual physical luminous brightness caused by backlight leakage when the brightness adjustment level of the display panel is 0, denoted as: Meanwhile, based on the perceptual needs of the human eye, the perceived brightness level at the black level is set to 0. At this point, , Substituting into the brightness reference model, we can derive... This enables the perception constant to accurately offset the residual brightness of the hardware.

[0027] In one embodiment, when determining the scaling factor, the maximum display brightness of the display panel can be determined first, and then the scaling factor can be determined based on the difference between the maximum display brightness and the hardware residual brightness.

[0028] For example: The maximum display brightness of the display panel is measured using a brightness detection device, which is the highest physical brightness intensity that the display panel's backlight module can output, denoted as . At the same time, the perceived brightness level corresponding to the maximum display brightness of the display panel will be set to 100. At this time, , and Substituting into the brightness reference model, the following is derived: .

[0029] The above method allows us to determine the values ​​of the perception constant and the scaling factor, ensuring that the perceived brightness level of the brightness reference model strictly matches the brightness adjustment levels from 0 to 100, while the physical brightness value falls within a certain range. Between I_max and I_max.

[0030] Step S102: Measure the luminance curve of each monochromatic light in the three primary colors of the display panel, and determine the PWM dimming control parameters of each monochromatic light at each gray level.

[0031] The core of this step is to obtain the correspondence between the brightness characteristics of each monochromatic light (red, green, and blue) when it emits light independently and the PWM dimming control parameters, so as to provide basic data for subsequent fusion of the three primary colors and reverse derivation of parameters.

[0032] PWM stands for Pulse Width Modulation, which is used to control output power or brightness by rapidly switching on and off and adjusting the pulse on-time (duty cycle).

[0033] The luminance curve is used to characterize the one-to-one correspondence between grayscale and actual luminance under a single monochromatic light. The three primary colors of light include red, green and blue monochromatic light, and the luminance curve includes the luminance curves corresponding to red, green and blue respectively.

[0034] PWM dimming control parameters include, but are not limited to, at least one of the following: PWM duty cycle, PWM output power, drive voltage and current, and pulse amplitude.

[0035] In one embodiment, the luminance curves of red, green, and blue monochromatic lights and the corresponding PWM dimming control parameters are measured using the same method.

[0036] For example, taking a target monochromatic light (any one of red, green, or blue) as an example, the backlight module of the display panel is driven and controlled individually, turning on only the LED backlight corresponding to the target monochromatic light. In this way, the target monochromatic light can be released by driving the display panel individually, while other monochromatic lights are turned off, avoiding brightness interference between different monochromatic lights. Then, the luminance of the target monochromatic light at different gray levels is collected to generate the luminance curve of the target monochromatic light.

[0037] During grayscale brightness acquisition, the grayscale of the target monochromatic light can be adjusted sequentially from 0 to 255 (or the maximum grayscale range supported by the panel). At each grayscale, a brightness detection device is used to acquire the actual luminous brightness of the target monochromatic light at that grayscale. Then, with the grayscale as the abscissa and the corresponding acquired luminous brightness as the ordinate, a luminous brightness curve of the target monochromatic light is fitted and generated. This curve can intuitively reflect the correlation between the grayscale changes and the luminous brightness of the target monochromatic light.

[0038] Simultaneously, the PWM dimming control parameters (such as duty cycle value) that drive the target monochromatic light to achieve the corresponding luminous brightness are recorded at each gray level. A correspondence table of gray level, PWM dimming control parameters, and luminous brightness of the target monochromatic light is established to achieve accurate retrieval of PWM dimming control parameters at any gray level and any brightness.

[0039] Repeat the above steps to measure and obtain the luminance curves of red, green and blue monochromatic lights, as well as the PWM dimming control parameters of each monochromatic light at all gray levels, to complete the acquisition and calibration of basic data.

[0040] Step S103: Based on the preset light intensity ratio, the luminance curves of each monochromatic light are fused to obtain a fusion curve, and the fusion curve is corrected using a luminance reference model.

[0041] This step consists of two core components: curve fusion and curve correction. First, the brightness curves of all monochromatic lights are fused into a fusion curve using a preset light intensity ratio. Then, a brightness reference model that conforms to human eye perception is used to correct the fusion curve, ensuring that the corrected fusion curve matches the logarithmic perception characteristics of the human eye. The fusion curve refers to the curve obtained by weighting and superimposing the brightness curves of red, green, and blue monochromatic lights according to a preset light intensity ratio, thus representing the correspondence between grayscale and the total physical brightness of white light.

[0042] In one embodiment, since there is a direct correlation between the minimum display brightness and the brightness curves of the three primary colors, constraints can be set for the minimum display brightness to improve the dimming effect.

[0043] Specifically, the constraint is that the minimum display brightness of the display panel's backlight is greater than the product of the maximum display brightness and a preset ratio value. For example, if the preset ratio value is 20%, then the minimum display brightness is greater than 20% of the maximum display brightness.

[0044] The direct correlation between minimum display brightness and the brightness curves of the three primary colors includes: First, the minimum display brightness affects the linearity of red light. For example, when the minimum display brightness is 20% greater than the maximum display brightness, the brightness of red light is more linear, which can effectively reduce the influence of the chopper fluorescence curve.

[0045] Secondly, the minimum display brightness will affect the light intensity ratio of the three primary colors. If the minimum display brightness is greater than 20% of the maximum display brightness, then the brightness of red light will be at least 20% of the brightness of white light, and there will be no color shift due to the low brightness of red light.

[0046] Third, the minimum display brightness affects the reflected light from the display panel. If the minimum display brightness is 20% greater than the maximum display brightness, the proportion of reflected light entering the human eye can be reduced, making the dimming experience smoother.

[0047] In one embodiment, the preset light intensity ratio can refer to the ratio of the luminance of red, green and blue primary colors. The preset light intensity ratio is a fixed ratio preset according to the color calibration requirements of the display panel and the white light color rendering effect.

[0048] Specifically, for work areas (such as studies, offices, or precision workbenches), the core objectives of light intensity ratio are high definition, high concentration, and reduced eye strain. If a standard daylight source (white light) with a synthesized color temperature of 6500K is desired, the luminous flux (brightness) ratio of the three primary colors (red, green, and blue) should be: a preset light intensity ratio (brightness ratio) of red light greater than 20%, and a preset light intensity ratio (brightness ratio) of blue light greater than 8%. For example, to maintain a constant brightness across the entire brightness range, avoid color shifts during dimming, and accurately reflect the actual indoor light ratios, while considering both viewing experience and eye strain, this application sets the preset light intensity ratios of red, green, and blue light to 30%, 60%, and 10% (i.e., 3:6:1) under the given constraints.

[0049] In the curve fusion process, based on a preset ratio of red, green, and blue light intensity, corresponding weighting coefficients are assigned to the luminance curves of the three monochromatic lights, with the weighting coefficients matching the intensity ratios. Then, a weighted summation is performed on the luminance curves of the three monochromatic lights. Specifically, for each luminance node on the luminance curve, the sum of the products of the luminance of the three monochromatic lights at that luminance node and their corresponding weighting coefficients is used as the total luminance of white light at that luminance node. Finally, using grayscale as the x-axis and the weighted summation of the total luminance of white light as the y-axis, a fused white light luminance curve is generated. This fused curve represents the correspondence between grayscale and the total physical luminance of white light when the three primary colors are emitted in a preset ratio. Here, a luminance node refers to the luminance point corresponding to each grayscale level.

[0050] Before curve correction, the fusion curve is a white light physical brightness curve based on a preset light intensity ratio. This fusion curve does not conform to the perceptual characteristics of human vision and needs to be perceptually corrected using a brightness reference model to ensure that the corrected fusion curve can accurately map physical brightness to the subjectively perceived brightness level of the human eye. The specific correction steps are as follows: During curve correction, all physical brightness values ​​on the fusion curve can be extracted. Each physical brightness value is then substituted into the brightness reference model to calculate the perceived brightness level corresponding to each physical brightness value. Next, the coordinate system of the fusion curve is transformed using the perceived brightness level as the abscissa and the corresponding physical brightness value as the ordinate. The transformed coordinate points are then smoothly fitted to generate the corrected fusion curve.

[0051] The corrected fusion curve accurately represents the correspondence between the subjective perceived brightness level and the actual physical brightness of white light, and perfectly matches the brightness adjustment levels from 0 to 100, providing a basis for determining the target brightness for each subsequent level. Simultaneously, the corrected fusion curve retains the color characteristics of the preset light intensity ratio of the three primary colors while conforming to the perceptual laws of the human eye, solving the problem of mismatch between physical brightness and subjective perception in traditional dimming.

[0052] Step S104: Based on the corrected fusion curve and PWM dimming control parameters, the target dimming parameters corresponding to the three primary colors of light at each brightness adjustment level of the display panel are derived in reverse.

[0053] In this step, by splitting the total brightness, matching the brightness of monochromatic light, and deriving the PWM parameters in reverse, the target dimming parameters corresponding to the red, green, and blue primary colors of light are obtained for each brightness adjustment level from 0 to 100, and it is ensured that the three primary colors of light always emit light according to the preset light intensity ratio without color deviation.

[0054] It should be noted that the target dimming parameter can refer to the target PWM dimming control parameter. The name of the target dimming parameter is intended to distinguish it from the uncorrected original PWM dimming control parameter.

[0055] The brightness adjustment level of the display panel is 0 to 100 levels. For each brightness adjustment level, the same reverse derivation process is performed.

[0056] The following reference Figure 2 This section will introduce the process of determining the target dimming parameters.

[0057] Figure 2 A flowchart illustrating the steps for determining the target dimming parameters provided in an embodiment of this application is shown, as follows: Figure 2 As shown, the steps for determining the target dimming parameters include: Step S1041: For each brightness adjustment level, determine the target total brightness corresponding to that brightness adjustment level based on the corrected fusion curve.

[0058] Taking any target brightness adjustment level N as an example, determine the corresponding perceived brightness level based on the target brightness adjustment level N. Then, the target total brightness (i.e. the total physical brightness of the white light that the display panel backlight needs to output) is determined from the corrected fusion curve at the perceived brightness level.

[0059] Step S1042: According to the preset light intensity ratio, the total target brightness is divided into the target brightness of each monochromatic light.

[0060] According to the preset light intensity ratio, the total target brightness is divided into the target brightness of each of the three monochromatic lights: red, green, and blue. For example, if the preset light intensity ratio is 3:6:1, and the total number of parts is the sum of 3, 6, and 1, then the target brightness of red light is the total target brightness multiplied by 0.3, the target brightness of blue light is the total target brightness multiplied by 0.6, and the target brightness of green light is the total target brightness multiplied by 0.1, ensuring that the brightness ratio of the three primary colors is always consistent with the preset value.

[0061] Step S1043: Based on the determined PWM dimming control parameters for each monochromatic light at each gray level, the target dimming parameters corresponding to the target brightness of each monochromatic light are derived in reverse.

[0062] For each monochromatic light, the correspondence table of gray level-PWM dimming control parameters-luminous brightness of the monochromatic light measured in step S102 is retrieved, the gray level corresponding to the target brightness of the monochromatic light is found, and then the PWM dimming control parameters under the gray level are determined. The PWM dimming control parameters are used as the target dimming parameters of the monochromatic light under the target brightness adjustment level N.

[0063] Repeat the above steps to calculate each brightness adjustment level in turn, and finally obtain the target dimming parameters corresponding to the three primary colors of red, green and blue light at each brightness level, so as to achieve fine parameter calibration for all levels.

[0064] It's important to note that before and after curve blending correction, the PWM dimming control parameters for monochromatic light remain unchanged at each grayscale level. That is, grayscale g corresponds to brightness L and PWM dimming control parameters. This correspondence is inherent to the hardware and therefore remains constant. After curve blending correction, the change is not in the PWM dimming control parameters corresponding to monochromatic light, but rather in which set of PWM dimming control parameters is used for each brightness adjustment level. Before correction, each brightness adjustment level uses non-linear, non-smooth, and eye-friendly PWM dimming control parameters; after correction, each brightness adjustment level uses dimming parameters that are more visually pleasing, linear, smooth, and eye-friendly.

[0065] If the fusion curve is not corrected and the three colors of light are directly fused according to a preset intensity ratio, the resulting white light brightness will exhibit almost no change at low levels, abrupt changes in the middle, and excessive brightness at high levels, causing discomfort to the human eye. The purpose of the brightness reference model is to convert the inherent curve of the hardware into a curve that is comfortable for the human eye.

[0066] For example, assuming the red backlight brightness is 50 nits and the PWM duty cycle is 40%, and the red backlight brightness is 60 nits and the PWM duty cycle is 42%. Without curve blending correction, when the brightness adjustment level is 45, the system will select the PWM duty cycle (i.e., 40%) corresponding to the red backlight brightness of 50 nits for PWM dimming. With curve blending correction, the brightness reference model can determine that when the brightness adjustment level is 50, the brightness needs to be increased to better match the subjective perception characteristics of the human eye. For example, if the red backlight brightness needs to be 60 nits, the system will select the PWM duty cycle (i.e., 42%) corresponding to the red backlight brightness of 60 nits for PWM dimming.

[0067] Step S105: Establish a mapping relationship between the brightness adjustment level and the target dimming parameter, and use the mapping relationship to perform PWM dimming of the display panel.

[0068] In this step, a mapping relationship is established to enable the rapid retrieval and application of dimming parameters, transforming the refined parameters derived in the previous steps into actual executable dimming control, thus ensuring the real-time performance and accuracy of the dimming process.

[0069] First, establish a mapping relationship between brightness adjustment levels and target dimming parameters.

[0070] Specifically, a mapping table can be constructed between brightness adjustment levels and target dimming parameters. This mapping table has rows representing brightness adjustment levels from 0 to 100, and columns representing the three primary colors of light: red, green, and blue. The values ​​in the table represent the target dimming parameters (such as duty cycle) for each monochromatic light at the corresponding brightness adjustment level. This mapping table is then stored in the memory of the main control chip of the display panel, supporting fast reading and retrieval of the mapping table by the main control chip. It can also be updated and calibrated offline according to the actual application requirements of the display panel.

[0071] The mapping relationship is a one-to-one correspondence, with each brightness adjustment level uniquely corresponding to a set of target dimming parameters for the three primary colors of red, green, and blue. All parameters ensure that the intensity ratio of the three primary colors is constant and conforms to the perceptual characteristics of the human eye.

[0072] Then, PWM dimming is performed on the display panel based on the mapping relationship.

[0073] Specifically, when a user adjusts the brightness of the display panel (e.g., by pressing a button, touching the screen, or using software commands), the main control chip of the display panel identifies the target brightness adjustment level selected by the user and retrieves the aforementioned mapping table from the memory. It quickly reads the target dimming parameters for the red, green, and blue primary colors corresponding to the target brightness adjustment level. Then, according to the read target dimming parameters, it performs PWM drive control on the backlight LEDs of the red, green, and blue primary colors respectively, adjusting the backlight brightness of each monochromatic light so that the three primary colors emit light according to the preset light intensity ratio and merge into white light, achieving the total brightness corresponding to the target level.

[0074] By directly retrieving the above mapping relationship, there is no need for complex formula calculations and parameter derivations in real time, which greatly improves the response speed of dimming control and meets users' real-time needs for brightness adjustment.

[0075] The PWM dimming method for backlight brightness provided in this application has the following technical effects: First, it can construct a brightness reference model (also known as a dimming model) based on the subjective brightness perception characteristics of the human eye, so that the changes of each brightness adjustment level conform to the laws of visual perception. The dimming process is smooth and uniform, without obvious stepping or low brightness jumps, which significantly improves visual comfort and reduces visual fatigue during long-term viewing.

[0076] Secondly, the ratio of the three primary color light intensity is kept constant within the full brightness adjustment range, effectively avoiding color deviation in the dimming process and ensuring the consistency and accuracy of color display under different brightness levels.

[0077] Third, by using black level compensation to incorporate residual hardware brightness into the brightness reference model for cancellation, the black level performance at the lowest brightness is improved, making the zero brightness adjustment level closer to the pure black effect, and improving the screen contrast and low-light display quality.

[0078] Fourth, the PWM dimming control parameters are reverse-matched based on the measured luminance curve of monochromatic light, making the parameter configuration accurate and reliable. The algorithm is simple to implement and highly adaptable, which can improve the overall backlight dimming effect without increasing hardware costs.

[0079] Based on the same inventive concept, this application also provides a PWM dimming device for backlight brightness corresponding to the PWM dimming method for backlight brightness. Since the principle of the device in this application is similar to the PWM dimming method for backlight brightness described above in this application, the implementation of the device can refer to the implementation of the method, and the repeated parts will not be described again.

[0080] Please see Figure 3 , Figure 3 This is a schematic diagram of a PWM dimming device for backlight brightness provided in an embodiment of this application. Figure 3As shown, the PWM dimming device 200 for backlight brightness includes: Model building module 201 is used to build a brightness reference model that matches the visual perception characteristics of the human eye; The curve measurement module 202 is used to measure the luminance curve of each monochromatic light in the three primary colors of the display panel, and to determine the PWM dimming control parameters of each monochromatic light at each gray level. The luminance curve is used to characterize the correspondence between gray level and luminance under the monochromatic light. The fusion and correction module 203 is used to fuse the luminance curves of each monochromatic light based on a preset light intensity ratio to obtain a fusion curve, and to correct the fusion curve using the luminance reference model. The parameter determination module 204 is used to reverse deduce the target dimming parameters corresponding to the three primary colors of light at each brightness adjustment level of the display panel based on the corrected fusion curve and the PWM dimming control parameters. The brightness adjustment module 205 is used to establish a mapping relationship between the brightness adjustment level and the target dimming control parameter, and to use the mapping relationship to perform PWM dimming of the display panel.

[0081] Please see Figure 4 , Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Figure 4 As shown, the electronic device 300 includes a processor 310, a memory 320, and a bus 330.

[0082] The memory 320 stores machine-readable instructions executable by the processor 310. When the electronic device 300 is running, the processor 310 and the memory 320 communicate via the bus 330. When the machine-readable instructions are executed by the processor 310, they can perform the operations described above. Figure 1 The specific implementation of the PWM dimming method for backlight brightness in the method embodiment shown can be found in the method embodiment, and will not be repeated here.

[0083] This application also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, can perform the above-described actions. Figure 1 The specific implementation of the PWM dimming method for backlight brightness in the method embodiment shown can be found in the method embodiment, and will not be repeated here.

[0084] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0085] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the shown or discussed mutual couplings, direct couplings, or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0086] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0087] In addition, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0088] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a processor-executable, non-volatile, computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0089] Finally, it should be noted that the above-described embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The scope of protection of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the scope of the technology disclosed in this application. Such modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A PWM dimming method for backlight brightness, characterized in that, include: Construct a brightness reference model that matches the visual perception characteristics of the human eye; The luminance curves of each monochromatic light in the three primary colors of the display panel are measured respectively, and the PWM dimming control parameters of each monochromatic light at each gray level are determined. The luminance curves are used to characterize the correspondence between gray level and luminance under the monochromatic light. The luminance curves of each monochromatic light are fused based on a preset light intensity ratio to obtain a fusion curve, and the fusion curve is corrected using the luminance reference model. Based on the corrected fusion curve and the PWM dimming control parameters, the target dimming parameters corresponding to the three primary colors of light at each brightness adjustment level of the display panel are derived in reverse. Establish a mapping relationship between brightness adjustment levels and target dimming control parameters, and use the mapping relationship to perform PWM dimming of the display panel.

2. The method according to claim 1, characterized in that, Based on the corrected fusion curve and PWM dimming control parameters, the steps for reverse-deriving the dimming parameters corresponding to the three primary colors of light at each brightness adjustment level of the display panel include: For each brightness adjustment level, the target total brightness corresponding to that brightness adjustment level is determined based on the corrected fusion curve. According to the preset light intensity ratio, the total target brightness is divided into the target brightness of each monochromatic light; Based on the determined PWM dimming control parameters for each monochromatic light at each gray level, the target dimming parameters corresponding to the target brightness of each monochromatic light are derived in reverse.

3. The method according to claim 1, characterized in that, The step of fusing the luminance curves of each monochromatic light based on a preset light intensity ratio to obtain a fused curve includes: According to the preset light intensity ratio, the luminance curves corresponding to the three primary colors are weighted and fused to obtain the fusion curve.

4. The method according to claim 1, characterized in that, The step of separately measuring the luminance curve of each monochromatic light in the three primary colors of the display panel includes: For a target monochromatic light, the display panel is driven to release the target monochromatic light separately, while other monochromatic lights are turned off. The luminance of the target monochromatic light at different gray levels is collected to generate the luminance curve of the target monochromatic light.

5. The method according to claim 1, characterized in that, The brightness reference model states that the perceived brightness level is equal to the sum of the product of the scaling factor and the natural logarithm of the physical brightness intensity, and the perception constant.

6. The method according to claim 5, characterized in that, The sensing constant is determined in the following manner: Determine the hardware residual brightness of the display panel at black level; The perception constant is determined based on the residual brightness of the hardware.

7. The method according to claim 6, characterized in that, The scaling factor is determined in the following manner: Determine the maximum display brightness of the display panel; The scaling factor is determined based on the difference between the maximum display brightness and the residual hardware brightness.

8. The method according to claim 1, characterized in that, The minimum display brightness of the display panel is greater than the product of the maximum display brightness and a preset ratio value.

9. The method according to claim 8, characterized in that, When the minimum display brightness of the display panel is greater than the product of the maximum display brightness and a preset ratio, the preset intensity ratio of red light in the three primary colors is greater than 20%, and the preset intensity ratio of blue light is greater than 8%.

10. A PWM dimming device for backlight brightness, characterized in that, include: The model building module is used to build a brightness reference model that matches the visual perception characteristics of the human eye; The curve measurement module is used to measure the luminance curve of each monochromatic light in the three primary colors of the display panel, and to determine the PWM dimming control parameters of each monochromatic light at each gray level. The luminance curve is used to characterize the correspondence between gray level and luminance under the monochromatic light. The fusion and correction module is used to fuse the luminance curves of each monochromatic light based on a preset light intensity ratio to obtain a fusion curve, and to correct the fusion curve using the luminance reference model. The parameter determination module is used to reverse deduce the target dimming parameters corresponding to the three primary colors of light at each brightness adjustment level of the display panel based on the corrected fusion curve and the PWM dimming control parameters. The brightness adjustment module is used to establish a mapping relationship between the brightness adjustment level and the target dimming control parameter, and to perform PWM dimming of the display panel using the mapping relationship.

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