A brightness adjusting method of a backlight module and a related device

Abstract

The application provides a brightness adjusting method of a backlight module and related devices, the brightness adjusting method comprises: acquiring a brightness gray scale value of a light emitting area corresponding to each channel; determining a dimming mode corresponding to each channel according to the brightness gray scale value corresponding to each channel and a preset threshold value, and determining an amplitude and a duty cycle of a working current output by each channel according to a corresponding relationship between the working current and the brightness gray scale value of the channel under different dimming modes. In the embodiment of the application, the brightness adjusting method adopts a current adjusting mode under a low gray scale, the duty cycle of the working current remains unchanged, the amplitude of the working current is changed to adjust the brightness of the backlight module, so that the influence of the rising time and the falling time of the working current on the pulse waveform can be reduced, the influence of the parasitic capacitance of the wiring can be reduced, and the brightness linearity of the backlight module is improved.

Description

Technical Field

[0001] This application relates to the field of local dimming technology, and in particular to a method and device for adjusting the brightness of a backlight module. Background Technology

[0002] Liquid Crystal Displays (LCDs) hold a significant position in the market due to their advantages such as small size, low power consumption, and no radiation. An LCD consists of a liquid crystal display panel and a backlight module. The backlight module provides a backlight source for the liquid crystal display panel, enabling the LCD to display images.

[0003] A backlight module can be divided into multiple light-emitting areas, each with at least one light source, which can be a light-emitting diode (LED). The operating current of the light source in each area can be precisely controlled by a driver chip to achieve local dimming. However, in related technologies, the brightness linearity of the light source in the backlight module is relatively poor. Summary of the Invention

[0004] This application provides a method and related apparatus for adjusting the brightness of a backlight module, which can improve the brightness linearity of the light source in the backlight module.

[0005] In a first aspect, embodiments of this application provide a method for adjusting the brightness of a backlight module. First, a brief description of the structure of the backlight module is given. The backlight module may include at least two light sources and at least one driving chip. The backlight module is divided into at least two light-emitting areas, each light-emitting area having at least one light source. The driving chip includes at least one channel, which is used to provide operating current to the light source in the at least one light-emitting area.

[0006] The brightness adjustment method described above can be applied to the aforementioned driver chip. This brightness adjustment method may include: acquiring the brightness grayscale value of the light-emitting area corresponding to each channel; determining the dimming mode corresponding to each channel based on the brightness grayscale value and a preset threshold; and determining the amplitude and duty cycle of the output operating current of each channel based on the correspondence between the channel's operating current and the brightness grayscale value under different dimming modes. Specifically, when the brightness grayscale value corresponding to a channel is less than the preset threshold, the dimming mode corresponding to the channel is a current dimming mode, the duty cycle of the channel's output operating current remains unchanged, and the amplitude of the channel's output operating current is positively correlated with the brightness grayscale value. When the brightness grayscale value corresponding to a channel is greater than the preset threshold, the dimming mode corresponding to the channel is a pulse width modulation (PWM) dimming mode, the amplitude of the channel's output operating current remains unchanged, and the duty cycle of the channel's output operating current is positively correlated with the brightness grayscale value.

[0007] The brightness adjustment method provided in this application determines the dimming mode for each channel based on the obtained grayscale values ​​and preset thresholds corresponding to each channel. Based on the correspondence between the channel's operating current and the grayscale values ​​under different dimming modes, the amplitude and duty cycle of the operating current output by each channel can be determined, enabling regional dimming of the backlight module. When the grayscale value of a channel is less than the preset threshold, the dimming mode for that channel is a current adjustment mode, i.e., a current adjustment mode is used at low grayscale levels. The duty cycle of the operating current remains constant, and the brightness of the backlight module is adjusted by changing the amplitude of the operating current. This effectively reduces the influence of the rise and fall times of the operating current on the pulse waveform and reduces the influence of parasitic parameters in the wiring, effectively improving the brightness linearity of the backlight module at low grayscale levels. When the grayscale value of a channel is greater than the preset threshold, the dimming mode for that channel is a PWM dimming mode, i.e., a PWM dimming mode is used at high grayscale levels. The amplitude of the operating current remains constant, and the brightness of the backlight module is adjusted by changing the duty cycle of the operating current. Since the rise and fall times of the operating current have less impact on the pulse waveform at high grayscale levels, the backlight module exhibits higher brightness linearity at high grayscale levels. Furthermore, the use of PWM dimming mode at high grayscale levels also ensures the color stability of the backlight module. Therefore, the brightness adjustment method provided in this application embodiment can achieve high brightness linearity of the backlight module across all grayscale levels.

[0008] In one possible implementation of this application, the duty cycle of the operating current of the channel output is determined as follows: when the dimming mode corresponding to the channel is current dimming mode, the duty cycle of the operating current of the channel output is the ratio of a preset threshold to the maximum grayscale value of the backlight module; when the dimming mode corresponding to the channel is PWM dimming mode, the duty cycle of the operating current of the channel output is the ratio of the brightness grayscale value of the channel to the maximum grayscale value of the backlight module.

[0009] In PWM dimming mode, the duty cycle of the operating current is linearly related to the brightness grayscale value. When the duty cycle of the operating current is 100%, the corresponding brightness grayscale value is the maximum grayscale value of the backlight module. Therefore, the duty cycle of the operating current output by the channel is the ratio of the brightness grayscale value of the channel to the maximum grayscale value of the backlight module. The maximum grayscale value of the backlight module can be set according to its luminous capability; for example, the current maximum grayscale value of the backlight module is 4095. The specific value of the maximum grayscale value of the backlight module is not limited here. In current dimming mode, the duty cycle of the operating current remains constant regardless of the brightness grayscale value. Therefore, in current dimming mode, the duty cycle of the operating current is the duty cycle corresponding to the preset threshold Th, that is, the duty cycle of the operating current output by the channel is the ratio of the preset threshold to the maximum grayscale value of the backlight module.

[0010] In one possible implementation of this application, the amplitude of the operating current of the channel output is determined as follows: the hybrid dimming current gain corresponding to the channel is determined based on the brightness grayscale value and dimming mode of the channel; the amplitude of the operating current of the channel output is determined based on the determined hybrid dimming current gain corresponding to the channel, as well as the preset reference current and global current gain corresponding to the driver chip.

[0011] In current-based dimming mode, the amplitude of the operating current increases with the increase of the brightness grayscale value. In PWM dimming mode, the amplitude of the operating current is a constant. That is, the correspondence between the amplitude of the operating current and the brightness grayscale value differs in different dimming modes. Therefore, in this embodiment, the hybrid dimming current gain parameter is used to distinguish the correspondence between the amplitude of the operating current and the brightness grayscale value in different dimming modes. Specifically, the hybrid dimming current gain is related to the brightness grayscale value and dimming mode of the corresponding channel.

[0012] In one possible implementation of this application, the hybrid dimming current gain is determined as follows: when the dimming mode corresponding to the channel is current dimming mode, the hybrid dimming current gain is the ratio of the brightness grayscale value to a preset threshold; when the dimming mode corresponding to the channel is PWM dimming mode, the hybrid dimming current gain is 1.

[0013] Due to differences in current accuracy among channels in the driver chip, variations in the light source itself, and parasitic capacitance of signal traces, differences in brightness exist between different emitting areas at the same grayscale, resulting in poor brightness uniformity among the emitting areas in the backlight module, and consequently, poor display uniformity of the LCD. Therefore, to improve the brightness uniformity of each emitting area in the backlight module, this embodiment adjusts the brightness of different emitting areas by setting the local current gain corresponding to each channel. Specifically, determining the amplitude of the channel output current based on the determined hybrid dimming current gain corresponding to the channel, and the preset reference current and global current gain of the driver chip, can include: determining the amplitude of the channel output current based on the determined hybrid dimming current gain corresponding to the channel, the preset reference current and global current gain corresponding to the driver chip, and the preset local current gain corresponding to the channel; the local current gains corresponding to different channels can be different, therefore, by setting the local current gain corresponding to the channel, the amplitude of the channel output current can fluctuate within a certain range, for example, it can fluctuate within ±S%, where S>0. Wherein, the local current gain is between 0 and (2 p Within the range of -1), p represents the number of bits occupied by the local current gain. p is a positive integer, and its value can be determined according to the specifications of the driver chip. For example, p can be 6, but it can also be other values, which are not limited here. In specific implementation, multiple registers corresponding to each channel can be set in the driver chip to store the local current gain corresponding to each channel in the corresponding registers.

[0014] In this embodiment, by setting the local current gain corresponding to each channel, the brightness uniformity of each light-emitting area in the backlight module can be improved, so that the LCD displays better uniformity of the displayed image in scenarios such as displaying solid color images or large dynamic videos, thereby improving the display effect.

[0015] In one possible implementation of this application, the amplitude of the operating current output by the channel can conform to the following formula:

[0016] I ch =I ref *Gain1*Gain2*Gain3;

[0017] Among them, I ch Indicates the amplitude of the operating current output by the channel; I ref Gain1 represents the reference current corresponding to the driver chip; Gain2 represents the global current gain corresponding to the driver chip; Gain3 represents the local current gain corresponding to the channel; Gain4 represents the hybrid dimming current gain corresponding to the channel.

[0018] In this embodiment, the local current gain of each channel can be determined using a brightness uniformity calibration method for the backlight module. This brightness uniformity calibration method can be performed during the pre-shipment testing of the backlight module, or it can be performed using external testing equipment.

[0019] The brightness uniformity calibration method for the backlight module in this embodiment may include: setting the local current gain corresponding to each channel to the same initial value, and powering on the backlight module to illuminate each light source in the backlight module; acquiring the brightness of each light-emitting area in the backlight module; determining whether the brightness uniformity of the backlight module is greater than a first threshold; if yes, adjusting the local current gain corresponding to each channel; if no, discarding backlight modules with brightness uniformity less than the first threshold; after adjusting the local current gain corresponding to each channel, powering on the backlight module again to illuminate each light source in the backlight module; acquiring the brightness of each light-emitting area in the backlight module; determining whether the brightness uniformity of the backlight module is greater than a second threshold, the second threshold being greater than the first threshold; if yes, completing the adjustment of the local current gain corresponding to each channel; if no, continuing to adjust the local current gain corresponding to each channel.

[0020] After completing the brightness uniformity calibration of the backlight module, the adjusted local current gain for each channel is stored in the non-volatile memory within the driver chip. Thus, during the use of the LCD display, the driver chip directly accesses parameters such as the global current gain and the local current gain for each channel each time it is powered on. The driver chip only needs to obtain the brightness grayscale value sent by the controller to control the output operating current of each channel, making the control method relatively simple.

[0021] In one possible implementation of this application, the aforementioned adjustment of the local current gain corresponding to each channel may include: using the average brightness of each light-emitting region in the backlight module as the target brightness value, and adjusting the local current gain corresponding to each channel according to the target brightness value. In this embodiment, using the average brightness of each light-emitting region as the target brightness value, compared to using other values ​​as the target brightness value, allows for adjustment of the local current gain within a range of ±5%, thus narrowing the adjustment range of the local current gain and reducing the magnitude of change in the operating current. This avoids excessive changes in the operating current, which could lead to significant variations in the color and brightness of the light-emitting region.

[0022] Secondly, embodiments of this application also provide a driver chip, which includes at least one channel for providing operating current to a light source in at least one light-emitting area of ​​a backlight module. The driver chip provided in this application embodiment may further include a memory and a processor. The memory stores program instructions; the processor is used to call the program instructions stored in the memory and execute the above-described brightness adjustment method according to the obtained program, which will not be repeated here.

[0023] Thirdly, embodiments of this application also provide a backlight module, which includes: at least two light-emitting areas, a backlight panel, at least two light sources fixed on the backlight panel, and the aforementioned driving chip. Each light-emitting area has at least one light source. The driving chip is electrically connected to the backlight panel, and the driving chip includes at least one channel for providing operating current to the light sources in at least one light-emitting area.

[0024] Fourthly, embodiments of this application also provide a display device, which includes: a liquid crystal display panel and the aforementioned backlight module, wherein the backlight module is located on the light-incident surface side of the liquid crystal display panel.

[0025] Fifthly, embodiments of this application also provide a storage medium storing computer-executable instructions for causing a computer to perform the above-described brightness adjustment method. Attached Figure Description

[0026] Figure 1 A schematic diagram showing the relationship between the operating current and brightness for duty cycle dimming;

[0027] Figure 2 This is a schematic diagram illustrating the effect of the rise time and fall time of the operating current on the pulse waveform.

[0028] Figure 3 This is a schematic diagram of the backlight module in an embodiment of this application;

[0029] Figure 4 A schematic flowchart illustrating the brightness adjustment method for a backlight module provided in an embodiment of this application;

[0030] Figure 5 This is a schematic diagram illustrating the relationship between operating current and brightness grayscale value in an embodiment of this application;

[0031] Figure 6 This is another schematic diagram illustrating the relationship between operating current and brightness grayscale value in an embodiment of this application;

[0032] Figure 7 This is a schematic diagram illustrating the control of the operating current in an embodiment of this application;

[0033] Figure 8 This is a schematic diagram of the control architecture for the operating current in an embodiment of this application;

[0034] Figure 9 This is a schematic diagram illustrating the working principle of the processor in the embodiments of this application;

[0035] Figure 10 This is a flowchart illustrating the brightness uniformity calibration method for the backlight module in this embodiment of the application.

[0036] Figure 11 A schematic diagram comparing the brightness uniformity of the backlight modules before and after calibration.

[0037] Figure 12 This is a schematic diagram comparing the brightness linearity of the backlight module with that of the related technologies and embodiments of this application.

[0038] Figure label:

[0039] 101-Backlight panel; 102-Light source; 103-Driver chip; 1031-Processor; 104-Controller. Detailed Implementation

[0040] Backlight modules are primarily used in LCD monitors. Since the LCD panel itself does not emit light, a backlight module is placed on the light-incident side of the LCD panel to provide a backlight source, enabling the LCD to display an image. To improve the contrast ratio of an LCD monitor, the backlight module is typically divided into at least two light-emitting areas, each with at least one light source. The brightness of each light-emitting area in the backlight module can be adjusted according to the image to be displayed, making brighter areas brighter and darker areas darker, thus resulting in a higher contrast ratio for the LCD monitor.

[0041] In related technologies, pulse width modulation (PWM) dimming is typically used to dim the backlight module in specific areas. Figure 1 This diagram illustrates the relationship between the operating current and brightness for duty cycle dimming. Figure 1 As shown in the figure, the horizontal axis represents brightness, the vertical axis represents the operating current of the light source, and the pulse width of the operating current represents the duty cycle of the operating current. Figure 1 As shown, the amplitude of the operating current is constant. The brightness of the light source is adjusted by changing the duty cycle of the operating current. The lower the duty cycle of the operating current, the lower the brightness; the higher the duty cycle of the operating current, the higher the brightness. Using duty cycle dimming to dim the backlight module can keep the amplitude of the operating current of the light source constant, resulting in better color consistency of the light source.

[0042] Figure 2 This diagram illustrates the effect of the rise and fall times of the operating current on the pulse waveform. Figure 2 As shown, Figure 2 (1) in the figure represents the ideal pulse waveform of the operating current. A square wave is used as an example in the figure. Figure 2 (2) is the actual pulse waveform of the operating current. Due to the influence of the rise time Tr and fall time Tf of the operating current, it makes... Figure 2 The actual waveform of the pulse in (2) becomes trapezoidal. (Comparison) Figure 2As can be clearly seen from (1) and (2) in the diagram, the rise time Tr and fall time Tf of the operating current affect the pulse width of the operating current, thereby reducing the duty cycle of the operating current and affecting the brightness of the light source, resulting in poor brightness linearity. In particular, at low gray levels, the pulse width of the operating current is narrower, and the influence of the rise time Tr and fall time Tf on the pulse width is more obvious, making the brightness linearity of the light source even worse at low gray levels. Furthermore, the rise time Tr and fall time Tf of the operating current cannot be avoided due to the influence of physical traces, parasitic capacitance, and driving capability of the driver chip in the backlight module.

[0043] Therefore, in order to improve the brightness linearity of the light source in the backlight module, this application provides a brightness adjustment method and related apparatus for a backlight module. This backlight module can be applied to a liquid crystal display device. The backlight module is disposed on one side of the light-incident surface of the liquid crystal display panel to provide a backlight source for the liquid crystal display panel, enabling the liquid crystal display device to display an image.

[0044] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0045] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0046] In the description of this application, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0047] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0048] Figure 3 This is a schematic diagram of the backlight module in an embodiment of this application, as shown below. Figure 3 As shown, the backlight module can be a direct-lit backlight module. The backlight module may include at least one backlight panel 101, at least two light sources 102, at least one driver chip 103, and at least one controller 104. The backlight module may include a single backlight panel 101, or it may include at least two backlight panels 101 connected together. Each light source 102 in the backlight module is fixed to the backlight panel 101. The backlight module is divided into at least two light-emitting areas C, and each light-emitting area C contains at least one light source 102. The light source 102 can be a miniature light-emitting diode (mini LED), but it can also be other types of light-emitting devices; this is not limited here. The light-emitting areas C in the backlight module can be uniformly distributed or non-uniformly distributed. The division of the light-emitting areas C in the backlight module can be based on actual needs; this is not limited here. Figure 3 The box in the upper left corner is a partially enlarged schematic diagram of a light-emitting area C. When multiple light sources 102 are provided in the light-emitting area C, the multiple light sources 102 can be electrically connected in a series-parallel manner.

[0049] Continue to refer to Figure 3 The driver chip 103 in the backlight module is electrically connected to the backlight board 101, and all driver chips 103 are connected in series. The controller 104 is electrically connected to the driver chip 103. The driver chip 103 includes at least one channel, as shown in CH1, CH2...CHn in the figure. In this embodiment, a channel can refer to the output port of the driver chip 103, and each channel corresponds to at least one light-emitting area C. The controller 104 provides the driver chip 103 with the required brightness grayscale values ​​for each light-emitting area C, and the channels provide operating current to the light source 102 within the corresponding light-emitting area C. Thus, the driver chip 103 precisely controls the operating current of the light source 102 in each light-emitting area C to achieve local dimming.

[0050] Figure 4 This is a flowchart illustrating the brightness adjustment method for a backlight module provided in an embodiment of this application. This method can be applied to... Figure 3 In the system architecture shown, such as Figure 4 As shown, the brightness adjustment method provided in this application embodiment can be applied to... Figure 3 Any of the driver chips shown specifically includes:

[0051] S201. Obtain the brightness grayscale value of the light-emitting area corresponding to each channel;

[0052] S202. Based on the brightness grayscale value and preset threshold of each channel, determine the dimming mode of each channel, and based on the correspondence between the working current of the channel and the brightness grayscale value under different dimming modes, determine the amplitude and duty cycle of the working current output by each channel. Figure 5 This diagram illustrates the relationship between operating current and brightness grayscale value in an embodiment of this application. The horizontal axis represents the brightness grayscale value, and the vertical axis represents the operating current. Figure 5 As shown, when the brightness grayscale value corresponding to the channel is less than the preset threshold Th, the dimming mode corresponding to the channel is current dimming mode, the duty cycle of the channel output current remains unchanged, and the amplitude of the channel output current is positively correlated with the brightness grayscale value; when the brightness grayscale value corresponding to the channel is greater than the preset threshold Th, the dimming mode corresponding to the channel is pulse width modulation (PWM) dimming mode, the amplitude of the channel output current remains unchanged, and the duty cycle of the channel output current is positively correlated with the brightness grayscale value.

[0053] The brightness adjustment method provided in this application determines the dimming mode for each channel based on the obtained grayscale values ​​and preset thresholds corresponding to each channel. Based on the correspondence between the channel's operating current and the grayscale values ​​under different dimming modes, the amplitude and duty cycle of the operating current output by each channel can be determined, enabling regional dimming of the backlight module. When the grayscale value of a channel is less than the preset threshold, the dimming mode for that channel is a current adjustment mode, i.e., a current adjustment mode is used at low grayscale levels. The duty cycle of the operating current remains constant, and the brightness of the backlight module is adjusted by changing the amplitude of the operating current. This effectively reduces the influence of the rise and fall times of the operating current on the pulse waveform and reduces the influence of parasitic parameters in the wiring, effectively improving the brightness linearity of the backlight module at low grayscale levels. When the grayscale value of a channel is greater than the preset threshold, the dimming mode for that channel is a PWM dimming mode, i.e., a PWM dimming mode is used at high grayscale levels. The amplitude of the operating current remains constant, and the brightness of the backlight module is adjusted by changing the duty cycle of the operating current. Since the rise and fall times of the operating current have less impact on the pulse waveform at high grayscale levels, the backlight module exhibits higher brightness linearity at high grayscale levels. Furthermore, the use of PWM dimming mode at high grayscale levels also ensures the color stability of the backlight module. Therefore, the brightness adjustment method provided in this application embodiment can achieve high brightness linearity of the backlight module across all grayscale levels.

[0054] Simultaneously refer to Figure 3In step S201 above, the brightness grayscale values ​​of the light-emitting areas C corresponding to each channel obtained by the driver chip 103 are determined based on the display grayscale values ​​of the corresponding areas in the image to be displayed on the screen. Specifically, the controller 104 can determine the required brightness grayscale values ​​of the light-emitting areas corresponding to each channel based on the image to be displayed on the screen, and send the determined brightness grayscale values ​​of each channel to the corresponding driver chip 103. For example, if the image to be displayed on the screen is a picture where the central area is brighter and the peripheral area is darker, then the required brightness grayscale value of the light-emitting area corresponding to the central area is higher, and the required brightness grayscale value of the light-emitting area corresponding to the peripheral area is lower. In this way, the backlight module can adjust the brightness according to the image to be displayed on the screen, so that the brightness of the brighter areas in the display image after brightness adjustment is higher, and the brightness of the darker areas is darker, thereby improving the display contrast. In practical implementation, the grayscale value of the image to be displayed differs from the brightness grayscale value of the backlight module. For example, the grayscale value of the image to be displayed is generally within the range of 0 to 255, while when the brightness grayscale value occupies 12 bits, the brightness grayscale value of the backlight module is generally within the range of 0 to 4095. The controller 104 can convert the grayscale value of the image to be displayed into the brightness grayscale value required by each light-emitting area in the backlight module based on the correspondence between the grayscale value of the image to be displayed and the brightness grayscale value of the backlight module.

[0055] In step S202 above, the specific value of the preset threshold Th can be determined according to actual needs. For example, the critical value at which the brightness linearity of the backlight module in the related technology is significantly reduced can be used as the preset threshold Th. Optionally, the preset threshold Th can be 128. Of course, the preset threshold can also be other values, which are not limited here.

[0056] Figure 6 This is another schematic diagram illustrating the relationship between operating current and brightness grayscale value in an embodiment of this application. The horizontal axis represents the brightness grayscale value, and the vertical axis represents the operating current. For example... Figure 6 As shown in the figure, curve L1 represents the relationship between the duty cycle of the operating current and the grayscale value of the brightness. In current dimming mode, the duty cycle of the operating current is a constant. In PWM dimming mode, the duty cycle of the operating current and the grayscale value of the brightness are positively correlated, that is, the duty cycle of the operating current increases as the grayscale value of the brightness increases. Curve L2 represents the relationship between the amplitude of the operating current and the grayscale value of the brightness. In current dimming mode, the amplitude of the operating current and the grayscale value of the brightness are positively correlated, that is, the amplitude of the operating current increases as the grayscale value of the brightness increases. In PWM dimming mode, the amplitude of the operating current is a constant.

[0057] Reference Figure 6 In the curve L1, the duty cycle of the operating current of the channel output in the brightness adjustment method provided in this application embodiment can be determined in the following way:

[0058] When the dimming mode corresponding to the channel is current dimming mode, the duty cycle of the working current output by the channel is the ratio of the preset threshold to the maximum grayscale value of the backlight module.

[0059] When the dimming mode corresponding to the channel is PWM dimming mode, the duty cycle of the channel output operating current is the ratio of the brightness grayscale value of the channel to the maximum grayscale value of the backlight module.

[0060] from Figure 6 Curve L1 clearly shows that in PWM dimming mode, the duty cycle of the operating current and the brightness grayscale value have a linear relationship. When the duty cycle of the operating current is 100%, the corresponding brightness grayscale value is the maximum grayscale value of the backlight module. Therefore, according to curve L1, the duty cycle of the channel output operating current is the ratio of the brightness grayscale value of the channel to the maximum grayscale value of the backlight module. The maximum grayscale value of the backlight module can be set according to the backlight module's luminous capability. For example, the current maximum grayscale value of the backlight module is 4095; the specific value of the maximum grayscale value of the backlight module is not limited here. In current dimming mode, the duty cycle of the operating current remains constant with changes in the brightness grayscale value. Therefore, in current dimming mode, the duty cycle of the operating current is the duty cycle corresponding to the preset threshold Th, that is, the duty cycle of the channel output operating current is the ratio of the preset threshold to the maximum grayscale value of the backlight module.

[0061] In summary, the duty cycle of the channel output operating current can be determined using the following formula:

[0062]

[0063] Where PWM represents the duty cycle of the operating current, and U represents the brightness grayscale value. max This indicates the maximum grayscale value of the backlight module.

[0064] In the brightness adjustment method provided in this application embodiment, the amplitude of the operating current output by the channel can be determined in the following manner:

[0065] Determine the hybrid dimming current gain corresponding to the channel based on the corresponding brightness grayscale value and dimming mode;

[0066] Based on the determined hybrid dimming current gain corresponding to the channel, and the preset reference current and global current gain corresponding to the driver chip, the amplitude of the operating current output of the channel is determined.

[0067] Reference Figure 6Curve L2 in the diagram shows that in current dimming mode, the amplitude of the operating current increases with the increase of the brightness grayscale value. In PWM dimming mode, the amplitude of the operating current is a constant value. That is, the correspondence between the amplitude of the operating current and the brightness grayscale value is different in different dimming modes. Therefore, in this embodiment, the hybrid dimming current gain parameter is used to distinguish the correspondence between the amplitude of the operating current and the brightness grayscale value in different dimming modes. Specifically, the hybrid dimming current gain is related to the brightness grayscale value and dimming mode of the corresponding channel.

[0068] Figure 7 This is a schematic diagram illustrating the control of the operating current in an embodiment of this application, such as... Figure 7 As shown, the reference current I corresponding to the driver chip ref This can be understood as the current source for the driver chip. In practice, it can be set using an external resistor on the driver chip. Alternatively, other methods can be used, such as adjusting the current source through internal chip parameters or using an externally provided current source. The specific method for setting the current source is not limited here. The global current gain Gain1 is a global variable, meaning that the value of the global current gain Gain1 is the same for all channels in the driver chip. The meaning of global current gain Gain1 is to amplify the reference current I. ref To adjust the overall brightness of the backlight module, the global current gain Gain1 must be greater than 1. For example, a global current gain Gain1 of 1000 indicates that the reference current I... ref Amplified 1000 times. Of course, when the reference current I... ref When the value is too large, the global current gain Gain1 can also mean reducing the reference current I. ref That is, the value of global current gain Gain1 can also be less than 1, which is not limited here. In practical applications, global current gain Gain1 can be stored in the register inside the driver chip. For example, global current gain Gain1 can occupy m bits, where m is a positive integer. Of course, the size of the global current gain Gain1 can be set according to actual needs, which is not limited here.

[0069] Continue to refer to Figure 7 In the diagram, Gain3 represents the hybrid dimming current gain. Since different channels may correspond to different brightness grayscale values ​​and dimming modes, the hybrid dimming current gain Gain3 may also differ for different channels. This is based on the reference current I of the driver chip. ref The amplitude I of the channel output operating current can be determined by the global current gain Gain1 and the corresponding hybrid dimming current gain Gain3. ch Furthermore, the amplitude I of the operating current output by the channel ch In 0~Imax Within the range, where I max The maximum amplitude of the operating current (I) can be determined based on the performance parameters of the light source. max To prevent the amplitude I of the operating current output by the channel from being reduced. ch Excessive heat will burn out the light source.

[0070] Reference Figure 6 In the curve L2 shown in this application embodiment, the above-mentioned hybrid dimming current gain can be determined in the following manner:

[0071] When the dimming mode corresponding to the channel is current dimming mode, the hybrid dimming current gain is the ratio of the brightness grayscale value to the preset threshold.

[0072] When the dimming mode corresponding to the channel is PWM dimming mode, the hybrid dimming current gain is 1.

[0073] In other words, in this embodiment of the application, the above-mentioned hybrid dimming current gain can be expressed by the following formula:

[0074]

[0075] from Figure 6 Curve L2 clearly shows that in current dimming mode, the amplitude of the operating current has a linear relationship with the brightness grayscale value, while in PWM dimming mode, the amplitude of the operating current is a constant. To differentiate the correspondence between the amplitude of the operating current and the brightness grayscale value in different dimming modes, the hybrid dimming current gain is set differently in each mode. Specifically, in current dimming mode, the hybrid dimming current gain is the ratio of the brightness grayscale value to a preset threshold, thus ensuring a linear relationship between the amplitude of the operating current and the brightness grayscale value. In PWM dimming mode, the hybrid dimming current gain is a constant value of 1, thus ensuring a constant amplitude of the operating current. Therefore, in this embodiment, by setting the hybrid dimming current gain parameter, the amplitude of the operating current output by the channel can be made to meet the requirements... Figure 6 The trend shown by curve S2.

[0076] Due to differences in current accuracy among channels in the driver chip, variations in the light source itself, and parasitic capacitance of signal traces, brightness differences exist between different emitting areas at the same grayscale level. This results in poor brightness uniformity among the emitting areas in the backlight module, consequently leading to poor display uniformity of the LCD. Therefore, to improve the brightness uniformity of the emitting areas in the backlight module, this embodiment adjusts the brightness of different emitting areas by setting the local current gain corresponding to each channel. Specifically, determining the amplitude of the channel output operating current based on the determined hybrid dimming current gain corresponding to the channel, and the preset reference current and global current gain of the driver chip, may include:

[0077] Reference Figure 7 Based on the determined hybrid dimming current gain Gain3 corresponding to the channel, the preset reference current I corresponding to the driver chip is... ref The amplitude of the channel's output operating current is determined by the global current gain Gain1 and the preset local current gain Gain2 corresponding to the channel. Different channels can have different local current gains Gain2; therefore, the amplitude of the channel's output operating current I can be adjusted by setting the local current gain Gain2 corresponding to each channel. ch It fluctuates within a certain range, for example, it can fluctuate within ±S%, where S > 0. The local current gain Gain2 is between 0 and (2... p Within the range of -1), p represents the number of bits occupied by the local current gain Gain2. p is a positive integer, and its value can be determined according to the specifications of the driver chip. For example, p can be 6, but it can also be other values, which are not limited here. In specific implementation, multiple registers corresponding to each channel can be set in the driver chip, and the local current gain Gain2 corresponding to each channel can be stored in the corresponding registers.

[0078] In this embodiment, the local current gain Gain2 ranges from 0 to (2... p -1), which can correspond to the adjustment range of the amplitude of the working current from 1-S% to 1+S%. In practical applications, the local current gain Gain2 of each channel can be determined according to the brightness difference of different light-emitting areas.

[0079] In this embodiment, by setting the local current gain corresponding to each channel, the brightness uniformity of each light-emitting area in the backlight module can be improved, so that the LCD displays better uniformity of the displayed image in scenarios such as displaying solid color images or large dynamic videos, thereby improving the display effect.

[0080] Figure 8 This is a schematic diagram of the control architecture for the operating current in an embodiment of this application, as shown below. Figure 8As shown, the amplitude of the operating current output by the channel can conform to the following formula:

[0081] I ch =I ref *Gain1*Gain2*Gain3;

[0082] Among them, I ch Indicates the amplitude of the operating current output by the channel; I ref Gain1 represents the reference current corresponding to the driver chip; Gain2 represents the global current gain corresponding to the driver chip; Gain3 represents the local current gain corresponding to the channel; Gain4 represents the hybrid dimming current gain corresponding to the channel.

[0083] Continue to refer to Figure 8 Reference current I ref Both the global current gain Gain1 and the global current gain Gain1 are pre-set global variables, i.e., the reference current I corresponding to each channel. ref The global current gain (Gain1) is the same for all channels. The local current gain (Gain2) is a local adjustment variable used to regulate the brightness of different light-emitting regions. It can be determined based on the brightness differences of different light-emitting regions; therefore, the local current gain (Gain2) for different channels can be different. The hybrid dimming current gain (Gain3) is used to distinguish different dimming modes and is determined by the brightness grayscale value of the corresponding channel and a preset threshold. Therefore, the hybrid dimming current gain (Gain3) for different channels may also be different. Based on the reference current I... ref The global current gain Gain1, local current gain Gain2, and hybrid dimming current gain Gain3 determine the amplitude of the operating current Ich1, Ich2, ..., Ich of each channel. n .

[0084] Optionally, a processor can be included in the driver chip to execute the brightness adjustment method described above. Figure 9 This is a schematic diagram illustrating the working principle of the processor in the embodiments of this application, such as... Figure 9 As shown, the processor 1031 obtains the required brightness grayscale value of the light-emitting area corresponding to each channel. The processor 1031 calls the global current gain Gain1 and the local current gain Gain2 corresponding to each channel stored in the register. The processor 1031 determines the dimming mode corresponding to each channel according to the brightness grayscale value and the preset threshold, and then determines the hybrid dimming current gain Gain3 corresponding to each channel. After that, the processor 1031 determines and outputs the duty cycle and amplitude of the working current corresponding to each channel.

[0085] In this embodiment, the local current gain of each channel can be determined using a brightness uniformity calibration method for the backlight module. This brightness uniformity calibration method can be performed during the pre-shipment testing of the backlight module, or it can be performed using external testing equipment. Figure 10 This is a flowchart illustrating the brightness uniformity calibration method for the backlight module in this embodiment of the application. Figure 10 As shown, the brightness uniformity calibration method for the backlight module in this embodiment may include:

[0086] S301. Set the local current gain of each channel to the same initial value. For example, the initial value can be 0. Of course, the initial value can also be other values. There is no limitation here.

[0087] S302. Power on the backlight module to illuminate each light source in the backlight module;

[0088] S303. Collect the brightness of each light-emitting area in the backlight module. Optionally, the brightness of each light-emitting area in the backlight module can be identified by taking a picture of the backlight module with a camera.

[0089] S304. Determine whether the brightness uniformity of the backlight module is greater than the first threshold a%, a > 0; if yes, proceed to step S306; if no, proceed to step S305. In this embodiment, by determining whether the brightness uniformity of the backlight module is greater than a%, it can be determined whether the brightness uniformity of the backlight module can be calibrated by adjusting the local current gain. If the brightness uniformity of the backlight module is less than a%, the backlight module may have defects and is difficult to calibrate by adjusting the local current gain. Therefore, backlight modules with brightness uniformity less than a% are discarded, and the local current gain corresponding to the backlight modules with brightness uniformity greater than a% is adjusted. In specific implementation, the specific value of a can be determined according to the local current adjustment capability of the driver chip. For example, if the local current adjustment capability of the driver chip is 90% to 110% (i.e., the above parameter S = 10), then a can be set to 80. That is to say, if the brightness difference of each light-emitting area in the backlight module exceeds 20%, the brightness uniformity of the backlight module is difficult to adjust, and the backlight module needs to be discarded.

[0090] S305. Discard backlight modules with brightness uniformity less than the first threshold a%.

[0091] S306. Adjust the local current gain corresponding to each channel; specifically, obtain the average brightness of each light-emitting area in the backlight module, use the average brightness of each light-emitting area in the backlight module as the target brightness value, adjust the local current gain corresponding to each channel according to the target brightness value, and then write the adjusted local current gain corresponding to each channel into the non-volatile memory inside the driver chip. The local current gain corresponding to each channel may be different. In this embodiment, the average brightness of each light-emitting area is used as the target brightness value. Compared with using other values ​​as the target brightness value, the local current gain can be adjusted within ±S%, which can reduce the adjustment range of the local current gain, thereby reducing the amount of change in the amplitude of the operating current and avoiding excessive changes in the color and brightness of the light-emitting area.

[0092] S307. Power on the backlight module to illuminate the light sources in the backlight module;

[0093] S308. Collect the brightness of each light-emitting area in the backlight module. Optionally, the brightness of each light-emitting area in the backlight module can be identified by taking a picture of the backlight module with a camera.

[0094] S309. Determine whether the brightness uniformity of the backlight module is greater than the second threshold b%. The second threshold is greater than the first threshold, i.e., b% > a%. For example, b can be 95. If yes, proceed to step S310. If no, return to step S306. In this embodiment, after adjusting the local current gain corresponding to each channel, by determining whether the brightness uniformity of the backlight module is greater than b%, it can be determined whether the backlight module meets the brightness uniformity requirement. If it meets the requirement, the brightness uniformity calibration of the backlight module is completed. If it does not meet the requirement, the local current gain corresponding to each channel is adjusted until the backlight module meets the brightness uniformity requirement.

[0095] S310. Complete the brightness uniformity calibration of the backlight module, that is, complete the adjustment of the local current gain corresponding to each channel.

[0096] After completing the brightness uniformity calibration of the backlight module, the adjusted local current gain for each channel is stored in the non-volatile memory within the driver chip. Thus, during the use of the LCD display, the driver chip directly accesses parameters such as the global current gain and the local current gain for each channel each time it is powered on. The driver chip only needs to obtain the brightness grayscale value sent by the controller to control the output operating current of each channel, making the control method relatively simple.

[0097] Figure 11 A schematic diagram showing the brightness uniformity comparison of the backlight module before and after calibration, as shown below. Figure 11 As shown, Figure 11 (1) in the figure represents the brightness data of each light-emitting area in the backlight module before calibration. Figure 11 (2) in the figure represents the adjusted local current gain for each channel. Figure 11 (3) in the figure represents the brightness data of each emitting area in the backlight module after calibration. For example, Figure 11 In (1), the brightness uniformity of the backlight module before calibration is approximately 82.9%. The area enclosed by the dashed line in the figure represents the area with poor brightness uniformity. After adjusting the local current gain corresponding to each channel, as shown in Figure (1), the brightness uniformity is improved. Figure 11 In (3), the brightness uniformity of the calibrated backlight module is approximately 97.2%. (Through...) Figure 11 It can be proven that the brightness adjustment method provided in the embodiments of this application can effectively improve the brightness uniformity of the backlight module.

[0098] Figure 12 This is a schematic diagram comparing the brightness linearity of the backlight module with that of the embodiments of this application. Figure 12 (1) in the figure is the brightness linearity curve of the backlight module obtained by using only PWM dimming in the related technology. Figure 12 (2) is the brightness linearity curve of the backlight module obtained by using a hybrid dimming method in the embodiments of this application, and, in Figure 12 In (1) and (2), the horizontal axis represents the grayscale value of brightness, and the vertical axis represents the brightness value. (Comparison) Figure 12 In (1) and (2), compared with the duty cycle dimming method used only in related technologies, the present application uses a hybrid dimming method. When the brightness grayscale value is less than the preset threshold Th, that is, at low grayscale, the brightness linearity of the backlight module is significantly improved. Furthermore, the present application uses a hybrid dimming method, and the brightness linearity of the backlight module is higher across the entire grayscale.

[0099] like Figure 12 In (2), the lower right corner is a pulse diagram of the working current in the embodiment of this application, where the dashed line represents the ideal waveform of the working current and the solid line represents the actual waveform of the working current. From Figure 12 As can be clearly seen in (2) of this application, the actual waveform of the working current in the embodiment of this application has a small difference from the ideal waveform. This is because the current adjustment mode is used at low gray levels, and the duty cycle of the working current remains unchanged. By changing the amplitude of the working current, the brightness of the backlight module is adjusted, thereby reducing the influence of the rise time and fall time of the working current on the pulse waveform. Therefore, the difference between the actual waveform of the working circuit and the ideal waveform is small. Furthermore, the duty cycle adjustment is used at high gray levels. By changing the duty cycle of the working current, the brightness of the backlight module is adjusted. At this time, the duty cycle of the working current is large, and the difference between the actual waveform of the working current and the ideal waveform is also small.

[0100] Based on the same technical concept, embodiments of this application also provide a driver chip, which includes at least one channel for providing operating current to a light source in at least one light-emitting area of ​​a backlight module. The driver chip provided in this application embodiment may further include a memory and a processor. The memory stores program instructions; the processor is used to call the program instructions stored in the memory and execute them according to the obtained program. Figure 4 or Figure 10 The method and process shown will not be repeated here.

[0101] Based on the same technical concept, embodiments of this application also provide a backlight module, such as... Figure 3 As shown, the backlight module may include: at least two light-emitting areas C, a backlight panel 101, at least two light sources 102 fixed on the backlight panel 101, and at least one of the aforementioned driving chips 103. Each light-emitting area C is provided with at least one light source 102. The driving chip 103 is electrically connected to the backlight panel 101. The driving chip 103 includes at least one channel, such as CH1, CH2...CHn in the figure. The channel is used to provide operating current to the light source 102 in at least one light-emitting area C.

[0102] Based on the same technical concept, this application also provides a display device, which includes: a liquid crystal display panel and any of the aforementioned backlight modules. The backlight module is located on one side of the light-incident surface of the liquid crystal display panel to provide a backlight for the liquid crystal display panel, enabling the display device to display an image. This display device can be any device with display function, such as a television, mobile phone, or tablet computer.

[0103] Based on the same technical concept, embodiments of this application also provide a storage medium storing computer-executable instructions for causing a computer to perform the above-described... Figure 4 or Figure 10 Any of the brightness adjustment methods shown.

[0104] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0105] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0106] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0107] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0108] The brightness adjustment method and related apparatus for the backlight module provided in this application determine the dimming mode for each channel based on the acquired grayscale values ​​and preset thresholds corresponding to each channel. Based on the grayscale values ​​and dimming modes of each channel, the amplitude and duty cycle of the output working current for each channel can be determined, achieving regional dimming of the backlight module. In low grayscale, a current adjustment mode is used, where the duty cycle of the working current remains constant. The brightness of the backlight module is adjusted by changing the amplitude of the working current. This reduces the influence of the rise and fall times of the working current on the pulse waveform and also reduces the influence of parasitic parameters in the wiring, significantly improving the brightness linearity of the backlight module in low grayscale. In high grayscale, a PWM dimming mode is used, where the amplitude of the working current remains constant. The brightness of the backlight module is adjusted by changing the duty cycle of the working current. Since the rise and fall times of the working current have less influence on the pulse waveform in high grayscale, the brightness linearity of the backlight module is higher in high grayscale. Furthermore, the use of PWM dimming mode in high grayscale ensures the color stability of the backlight module. Therefore, the brightness adjustment method provided in this application embodiment can ensure high brightness linearity of the backlight module across the entire grayscale. Furthermore, in this application embodiment, by setting the local current gain corresponding to each channel, the brightness uniformity of each light-emitting area in the backlight module can be improved, resulting in better uniformity of the displayed image and improved display effect when the liquid crystal display is showing solid color images or high dynamic range videos.

[0109] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0110] Obviously, those skilled in the art can make various modifications and variations to the embodiments of this application without departing from the spirit and scope of the embodiments of this application. Therefore, if these modifications and variations to the embodiments of this application fall within the scope of the claims of this application and their equivalents, this application also intends to include these modifications and variations.

Claims

1. A method for adjusting the brightness of a backlight module, characterized in that, The backlight module includes at least two light sources and at least one driving chip; the backlight module is divided into at least two light-emitting areas, and each light-emitting area is provided with at least one light source; the driving chip includes at least one channel, which is used to provide operating current to the light source in at least one of the light-emitting areas; The brightness adjustment method is applied to the driver chip and includes: Obtain the brightness grayscale value of the light-emitting region corresponding to each of the channels; Based on the brightness grayscale value corresponding to each channel and a preset threshold, the dimming mode corresponding to each channel is determined. Furthermore, based on the correspondence between the operating current and the brightness grayscale value of the channel under different dimming modes, the amplitude and duty cycle of the operating current output by each channel are determined. Specifically, when the brightness grayscale value corresponding to a channel is less than the preset threshold, the dimming mode corresponding to the channel is a current dimming mode, the duty cycle of the operating current output by the channel remains unchanged, and the duty cycle of the operating current output by the channel is the ratio of the preset threshold to the maximum grayscale value of the backlight module. The amplitude of the operating current output by the channel is positively correlated with the brightness grayscale value. When the brightness grayscale value corresponding to a channel is greater than the preset threshold, the dimming mode corresponding to the channel is a pulse width modulation (PWM) dimming mode, the amplitude of the operating current output by the channel remains unchanged, the duty cycle of the operating current output by the channel is positively correlated with the brightness grayscale value, and the duty cycle of the operating current output by the channel is the ratio of the brightness grayscale value corresponding to the channel to the maximum grayscale value of the backlight module.

2. The brightness adjustment method as described in claim 1, characterized in that, The amplitude of the operating current output by the channel is determined in the following manner: Based on the brightness grayscale value corresponding to the channel and the dimming mode, determine the hybrid dimming current gain corresponding to the channel; The amplitude of the operating current output by the channel is determined based on the determined hybrid dimming current gain corresponding to the channel, and the preset reference current and global current gain corresponding to the driver chip.

3. The brightness adjustment method as described in claim 2, characterized in that, The hybrid dimming current gain is determined as follows: When the dimming mode corresponding to the channel is the current dimming mode, the hybrid dimming current gain is the ratio of the brightness grayscale value to the preset threshold. When the dimming mode corresponding to the channel is PWM dimming mode, the hybrid dimming current gain is 1.

4. The brightness adjustment method as described in claim 2, characterized in that, The step of determining the amplitude of the operating current output by the channel based on the determined hybrid dimming current gain corresponding to the channel, and the preset reference current and global current gain of the driver chip, includes: Based on the determined hybrid dimming current gain corresponding to the channel, the preset reference current and global current gain corresponding to the driver chip, and the preset local current gain corresponding to the channel, the amplitude of the operating current output by the channel is determined; wherein, the local current gain is in the range of 0 to (2). p Within the range of -1), p is the number of bits occupied by the local current gain, and p is a positive integer.

5. The brightness adjustment method as described in claim 4, characterized in that, The amplitude of the operating current output by the channel is determined by the following formula: I ch =I ref Gain1 Gain2 Gain3; Among them, I ch Indicates the amplitude of the operating current output by the channel; I ref Gain1 represents the reference current corresponding to the driver chip; Gain2 represents the global current gain corresponding to the driver chip; Gain3 represents the local current gain corresponding to the channel; and Gain4 represents the hybrid dimming current gain corresponding to the channel.

6. The brightness adjustment method as described in claim 4 or 5, characterized in that, The local current gain corresponding to each of the aforementioned channels is determined in the following manner: Set the local current gain corresponding to each of the channels to the same initial value, and power on the backlight module to illuminate each light source in the backlight module. Collect the brightness of each light-emitting area in the backlight module; Determine whether the brightness uniformity of the backlight module is greater than a first threshold. If yes, then adjust the local current gain corresponding to each channel; if no, then discard the backlight module with brightness uniformity less than the first threshold. After adjusting the local current gain corresponding to each of the channels, the backlight module is powered on again to illuminate each of the light sources in the backlight module. Collect the brightness of each light-emitting region in the backlight module; Determine whether the brightness uniformity of the backlight module is greater than a second threshold, where the second threshold is greater than the first threshold; if yes, then complete the adjustment of the local current gain corresponding to each channel; if no, then continue to adjust the local current gain corresponding to each channel.

7. The brightness adjustment method as described in claim 6, characterized in that, The adjustment of the local current gain corresponding to each of the channels includes: The average brightness of each of the light-emitting regions in the backlight module is used as the target brightness value, and the local current gain corresponding to each channel is adjusted according to the target brightness value.

8. A driver chip, characterized in that, The driver chip includes at least one channel for providing operating current to a light source in at least one light-emitting area of ​​the backlight module; The driver chip also includes: Memory, used to store program instructions; The processor is configured to call program instructions stored in the memory and execute them according to the obtained program: Obtain the brightness grayscale value of the light-emitting region corresponding to each of the channels; Based on the brightness grayscale value corresponding to each channel and a preset threshold, the dimming mode corresponding to each channel is determined. Furthermore, based on the correspondence between the operating current and the brightness grayscale value of the channel under different dimming modes, the amplitude and duty cycle of the operating current output by each channel are determined. Specifically, when the brightness grayscale value corresponding to a channel is less than the preset threshold, the dimming mode corresponding to the channel is a current dimming mode, the duty cycle of the operating current output by the channel remains unchanged, and the duty cycle of the operating current output by the channel is the ratio of the preset threshold to the maximum grayscale value of the backlight module. The amplitude of the operating current output by the channel is positively correlated with the brightness grayscale value. When the brightness grayscale value corresponding to a channel is greater than the preset threshold, the dimming mode corresponding to the channel is a pulse width modulation (PWM) dimming mode, the amplitude of the operating current output by the channel remains unchanged, the duty cycle of the operating current output by the channel is positively correlated with the brightness grayscale value, and the duty cycle of the operating current output by the channel is the ratio of the brightness grayscale value corresponding to the channel to the maximum grayscale value of the backlight module.

9. The driver chip as described in claim 8, characterized in that, The processor determines the amplitude of the operating current output by the channel in the following manner: Based on the brightness grayscale value corresponding to the channel and the dimming mode, determine the hybrid dimming current gain corresponding to the channel; The amplitude of the operating current output by the channel is determined based on the determined hybrid dimming current gain corresponding to the channel, and the preset reference current and global current gain corresponding to the driver chip.

10. The driver chip as described in claim 9, characterized in that, The processor determines the hybrid dimming current gain in the following manner: When the dimming mode corresponding to the channel is the current dimming mode, the hybrid dimming current gain is the ratio of the brightness grayscale value to the preset threshold. When the dimming mode corresponding to the channel is PWM dimming mode, the hybrid dimming current gain is 1.

11. The driver chip as described in claim 9, characterized in that, The processor determines the amplitude of the operating current output by the channel based on the determined hybrid dimming current gain corresponding to the channel, and the preset reference current and global current gain of the driver chip, including: Based on the determined hybrid dimming current gain corresponding to the channel, the preset reference current and global current gain corresponding to the driver chip, and the preset local current gain corresponding to the channel, the amplitude of the operating current output by the channel is determined; wherein, the local current gain is in the range of 0 to (2). p Within the range of -1), p is the number of bits occupied by the local current gain.

12. The driver chip as described in claim 11, characterized in that, The processor determines the amplitude of the operating current output by the channel according to the following formula: I ch =I ref Gain1 Gain2 Gain3; Among them, I ch Indicates the amplitude of the operating current output by the channel; I ref Gain1 represents the reference current corresponding to the driver chip; Gain2 represents the global current gain corresponding to the driver chip; Gain3 represents the local current gain corresponding to the channel; and Gain4 represents the hybrid dimming current gain corresponding to the channel.

13. A backlight module, characterized in that, include: The system comprises at least two light-emitting areas, a backlight panel, at least two light sources fixed on the backlight panel, and a driver chip as described in any one of claims 8 to 12; each of the light-emitting areas is provided with at least one of the light sources; The driver chip is electrically connected to the backlight board, and the driver chip includes at least one channel for providing operating current to the light source in at least one of the light-emitting areas.

14. A display device, characterized in that, include: A liquid crystal display panel, and a backlight module as described in claim 13; The backlight module is located on the light-incident side of the liquid crystal display panel.

15. A storage medium, characterized in that, The storage medium stores computer-executable instructions, which are used to cause the computer to perform the brightness adjustment method according to any one of claims 1 to 7.

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