CN115240603A

CN115240603A - Brightness adjusting method of backlight module and related device

Info

Publication number: CN115240603A
Application number: CN202110442749.1A
Authority: CN
Inventors: 张世雄
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2021-04-23
Filing date: 2021-04-23
Publication date: 2022-10-25
Also published as: EP4310826A1; WO2022222969A1

Abstract

The application provides a brightness adjusting method of a backlight module and a related device, wherein the brightness adjusting method comprises the following steps: acquiring the brightness gray-scale value of the light-emitting area corresponding to each channel; and determining the dimming mode corresponding to each channel according to the brightness gray-scale value corresponding to each channel and a preset threshold, and determining the amplitude and the duty ratio of the working current output by each channel according to the corresponding relation between the working current of the channel and the brightness gray-scale value in different dimming modes. According to the brightness adjusting method in the embodiment of the application, the current adjusting mode is adopted at a low gray scale, the duty ratio of the working current is kept unchanged, and the brightness of the backlight module is adjusted by changing the amplitude of the working current, so that the influence of the rise time and the fall time of the working current on the pulse waveform can be reduced, the influence of the parasitic capacitance of wiring can be reduced, and the brightness linearity of the backlight module is improved.

Description

Brightness adjusting method of backlight module and related device

Technical Field

The present disclosure relates to the field of local dimming technologies, and in particular, to a brightness adjusting method for a backlight module and a related device.

Background

Since a Liquid Crystal Display (LCD) has advantages of small size, low power consumption, no radiation, and the like, the LCD occupies an important position in the market. The liquid crystal display comprises a liquid crystal display panel and a backlight module, wherein the backlight module can provide a backlight source for the liquid crystal display panel so that the liquid crystal display can realize picture display.

The backlight module can be divided into a plurality of light emitting areas, at least one light source is arranged in each light emitting area, the light source can be a light-emitting diode (LED), and the working current of the light source in each light emitting area can be accurately controlled through a driving chip so as to achieve the purpose of regional dimming. However, in the related art, the brightness linearity of the light source in the backlight module is poor.

Disclosure of Invention

The embodiment of the application provides a brightness adjusting method of a backlight module and a related device, which are used for improving the brightness linearity of a light source in the backlight module.

In a first aspect, an embodiment of the present application provides a brightness adjustment method for a backlight module. First, a simple description is given of the structure of the backlight module, which 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, at least one light source is arranged in each light-emitting area, the driving chip comprises at least one channel, and the channel is used for providing working current for the light source in the at least one light-emitting area.

The brightness adjusting method may be applied to the driving chip, and the brightness adjusting method may include: acquiring the brightness gray-scale value of the 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, and determining the amplitude and duty ratio of the working current output by each channel according to the corresponding relation between the working current of the channel and the brightness gray-scale value under different dimming modes; when the brightness gray-scale value corresponding to the channel is smaller than the preset threshold value, the dimming mode corresponding to the channel is a current dimming mode, the duty ratio of the working current output by the channel is kept unchanged, and the amplitude of the working current output by the channel is in a positive correlation with the brightness gray-scale value; when the brightness gray scale value corresponding to the 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 working current output by the channel remains unchanged, and the duty ratio of the working current output by the channel is in a positive correlation with the brightness gray scale value.

According to the brightness adjusting method provided by the embodiment of the application, the dimming mode corresponding to each channel can be determined according to the acquired brightness gray-scale value corresponding to each channel and the preset threshold, the amplitude and the duty ratio of the working current output by each channel can be determined according to the corresponding relation between the working current of the channel and the brightness gray-scale value under different dimming modes, and the regional dimming of the backlight module can be realized. When the luminance gray scale value corresponding to the channel is smaller than the preset threshold value, the dimming mode corresponding to the channel is a current regulation mode, namely the current regulation mode is adopted at a low gray scale, the duty ratio of the working current is kept unchanged, and the luminance of the backlight module is regulated by changing the amplitude of the working current, so that the influence of the rising time and the falling time of the working current on the pulse waveform can be effectively reduced, the influence of wiring parasitic parameters can be reduced, and the luminance linearity of the backlight module at the low gray scale is effectively improved. When the luminance gray scale value corresponding to the channel is larger than the preset threshold value, the dimming mode corresponding to the channel is a PWM dimming mode, namely the PWM dimming mode is adopted under the high gray scale, the amplitude of the working current is kept unchanged, and the luminance of the backlight module is adjusted by changing the duty ratio of the working current. Because the influence of the rise time and the fall time of the working current on the pulse waveform is small under the high gray scale, the brightness linearity of the backlight module is high under the high gray scale, and the color stability of the backlight module can be ensured by adopting a PWM dimming mode under the high gray scale. Therefore, the brightness adjusting method provided by the embodiment of the application can enable the brightness linearity of the backlight module to be higher under the full gray scale.

In one possible implementation manner of the present application, the duty ratio of the operating current output by the channel is determined as follows: when the dimming mode corresponding to the channel is the current dimming mode, the duty ratio of the working current output by the channel is the ratio of the preset threshold value to the maximum gray-scale value of the backlight module; when the dimming mode corresponding to the channel is the PWM dimming mode, the duty ratio of the working current output by the channel is the ratio of the brightness gray-scale value corresponding to the channel to the maximum gray-scale value of the backlight module.

In the PWM dimming mode, the duty ratio of the working current and the luminance gray scale value are in a linear relationship, and when the duty ratio of the working current is 100%, the corresponding luminance gray scale value is the maximum gray scale value of the backlight module, and thus, the duty ratio of the working current output by the channel is the ratio of the luminance gray scale value corresponding to the channel to the maximum gray scale value of the backlight module. For example, the maximum gray scale value of the backlight module is 4095, and a specific numerical value of the maximum gray scale value of the backlight module is not limited herein. In the current dimming mode, the duty ratio of the working current is kept unchanged along with the change of the brightness gray scale value, so that in the current dimming mode, the duty ratio of the working current is the duty ratio corresponding to the preset threshold Th, namely the duty ratio of the working current output by the channel is the ratio of the preset threshold to the maximum gray scale value of the backlight module.

In one possible implementation of the present application, the amplitude of the operating current output by the channel is determined as follows: determining the mixed dimming current gain corresponding to the channel according to the brightness gray-scale value and the dimming mode corresponding to the channel; and determining the amplitude of the working current output by the channel according to the determined mixed dimming current gain corresponding to the channel, and the preset reference current and global current gain corresponding to the driving chip.

In the current dimming mode, the amplitude of the working current increases with the increase of the brightness gray scale value, and in the PWM dimming mode, the amplitude of the working current is a fixed value, that is, in different dimming modes, the corresponding relationship between the amplitude of the working current and the brightness gray scale value is different, so in the embodiment of the present application, the parameter of the hybrid dimming current gain is used to distinguish the corresponding relationship between the amplitude of the working current and the brightness gray scale value in different dimming modes. Specifically, the hybrid dimming current gain is related to the luminance gray-scale value and the dimming mode corresponding to the channel.

In one possible implementation of the present application, the hybrid dimming current gain is determined as follows: when the dimming mode corresponding to the channel is the current dimming mode, the mixed dimming current gain is the ratio of the brightness gray-scale value to the preset threshold value; when the dimming mode corresponding to the channel is the PWM dimming mode, the hybrid dimming current gain is 1.

Due to the influence of factors such as current precision difference of each channel in the driving chip, self difference of the light source, parasitic capacitance of signal wiring and the like, different light emitting areas under the same brightness gray scaleThe brightness difference between the domains causes poor brightness uniformity of each light-emitting area in the backlight module, and further causes poor display uniformity of the liquid crystal display. Therefore, in order to improve the brightness uniformity of each light-emitting area in the backlight module, in the embodiment of the present application, the brightness of different light-emitting areas is adjusted by setting the local current gain corresponding to each channel. Specifically, the determining the amplitude of the working current output by the channel according to the determined mixed dimming current gain corresponding to the channel, and the preset reference current and global current gain of the driver chip may include: determining the amplitude of the working current output by the channel according to the determined mixed dimming current gain corresponding to the channel, the preset reference current and global current gain corresponding to the driving chip and the preset local current gain corresponding to the channel; the local current gains corresponding to different channels may be different, and thus, the amplitude of the operating current output by the channel may be made to float within a certain range, for example, may float within a range of ± S%, where S > 0, by setting the local current gains corresponding to the channels. Wherein the local current gain is in the range of 0 to (2) ^p In the range of-1), p is the bit number occupied by the local current gain, p is a positive integer, and the value of p may be determined according to the specification of the driver chip, for example, p may be 6, although p may also be other values, which is not limited herein. In a specific implementation, a plurality of registers corresponding to the channels may be disposed in the driver chip, and the local current gains corresponding to the channels are stored in the corresponding registers.

In the embodiment of the application, the brightness uniformity of each light emitting area in the backlight module can be improved by setting the local current gain corresponding to each channel, so that the uniformity of the displayed picture is better and the display effect is improved when the liquid crystal display displays scenes such as pure-color pictures or large dynamic videos.

In one possible implementation manner of the present application, the amplitude of the working current output by the channel may conform to the following formula:

I _ch ＝I _ref *Gain ₁ *Gain ₂ *Gain ₃ ；

wherein，I _ch Representing the amplitude of the operating current output by the channel; i is _ref The reference current corresponding to the driving chip is represented; gain ₁ Representing the corresponding global current gain of the driving chip; gain ₂ Representing the local current gain corresponding to the channel; gain ₃ Indicating the hybrid dimming current gain for the channel.

In the embodiment of the application, the local current gain corresponding to each channel can be determined by a brightness uniformity calibration method of the backlight module. The brightness uniformity calibration method can be executed in the testing process of the backlight module before the backlight module leaves factory, and the brightness calibration method can be executed in external testing equipment.

The method for calibrating the brightness uniformity of the backlight module in the embodiment of the application can comprise the following steps: setting local current gains corresponding to the channels to be the same initial value, and electrifying the backlight module to light each light source in the backlight module; collecting the brightness of each light emitting area in the backlight module; judging whether the brightness uniformity of the backlight module is greater than a first threshold value; if yes, adjusting the local current gain corresponding to each channel; if not, discarding the backlight module with the brightness uniformity smaller than the first threshold value; after the local current gain corresponding to each channel is adjusted, the backlight module is electrified again to light each light source in the backlight module; collecting the brightness of each light emitting area in the backlight module; judging whether the brightness uniformity of the backlight module is greater than a second threshold value, wherein the second threshold value is greater than the first threshold value; if so, completing the adjustment of the local current gain corresponding to each channel; if not, the local current gain corresponding to each channel is continuously adjusted.

And after the brightness uniformity of the backlight module is calibrated, solidifying the adjusted local current gain corresponding to each channel into a nonvolatile memory in the driving chip. Therefore, in the using process of the liquid crystal display, the driving chip can directly call parameters such as the global current gain and the local current gain corresponding to each channel when being powered on every time, the driving chip can control each channel to output the working current only by acquiring the brightness gray-scale value sent by the controller, and the control mode is simple.

In one possible implementation manner of the present application, the adjusting the local current gain corresponding to each channel may include: and adjusting the local current gain corresponding to each channel according to the target brightness value by taking the brightness average value of each light-emitting area in the backlight module as the target brightness value. In the embodiment of the application, the average brightness value of each light-emitting area is used as the target brightness value, and compared with other values used as the target brightness value, the local current gain can be adjusted within the range of +/-S%, and the adjustment range of the local current gain can be reduced, so that the variation of the amplitude of the working current is reduced, and the phenomenon that the variation of the working current is too large to cause the color and brightness of the light-emitting area to change too much is avoided.

In a second aspect, an embodiment of the present application further provides a driving chip, where the driving chip includes at least one channel, and the channel is used to provide an operating current to a light source in at least one light emitting region of a backlight module. The driving chip provided by the embodiment of the application can further include: a memory and a processor. Wherein the memory stores program instructions; the processor is configured to call the program instruction stored in the memory, and execute the flow of the brightness adjustment method according to the obtained program, which is not described repeatedly herein.

In a third aspect, an embodiment of the present application further provides a backlight module, where the backlight module includes: the backlight module comprises at least two light emitting areas, a backlight panel, at least two light sources fixed on the backlight panel and the driving chip. At least one light source is arranged in each light-emitting area. The driving chip is electrically connected with the backlight panel and comprises at least one channel, and the channel is used for providing working current for a light source in at least one light emitting area.

In a fourth aspect, an embodiment of the present application further provides a display device, including: the backlight module is positioned on one side of the light incident surface of the liquid crystal display panel.

In a fifth aspect, the present application further provides a storage medium, where the storage medium stores computer-executable instructions, and the computer-executable instructions are configured to enable a computer to execute the brightness adjustment method.

Drawings

FIG. 1 is a diagram illustrating duty cycle dimming operation current versus brightness;

FIG. 2 is a schematic diagram showing the effect of the rise time and fall time of the operating current on the pulse waveform;

FIG. 3 is a schematic structural diagram of a backlight module according to an embodiment of the present application;

fig. 4 is a schematic flowchart of a brightness adjustment method of a backlight module according to an embodiment of the present disclosure;

FIG. 5 is a diagram illustrating a relationship between a working current and a luminance gray-scale value according to an embodiment of the present disclosure;

FIG. 6 is a diagram illustrating another relationship between the operating current and the luminance gray-scale value in the embodiment of the present application;

FIG. 7 is a schematic control diagram of the operating current in the embodiment of the present application;

FIG. 8 is a schematic diagram of an exemplary embodiment of a control architecture for operating current;

FIG. 9 is a schematic diagram of the operation of a processor in an embodiment of the present application;

FIG. 10 is a flowchart illustrating a method for calibrating luminance uniformity of a backlight module according to an embodiment of the present disclosure;

FIG. 11 is a comparison diagram of brightness uniformity of the backlight module before and after calibration;

fig. 12 is a schematic diagram illustrating a comparison between brightness linearity of a backlight module according to the related art and that of the backlight module according to the embodiment of the present application.

Reference numerals:

101-backlight panel; 102-a light source; 103-a driving chip; 1031-a processor; 104-a controller.

Detailed Description

The backlight module is mainly applied to the liquid crystal display, and because the liquid crystal display panel does not emit light, the backlight module needs to be arranged 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, so that the liquid crystal display realizes picture display. In order to improve the display contrast of the lcd, the backlight module is usually divided into at least two light-emitting areas, and at least one light source is disposed in each light-emitting area. The brightness of each light emitting area in the backlight module can be adjusted according to the picture to be displayed, so that the brightness of a brighter area in the display picture is higher, the brightness of a darker area is darker, and the display contrast of the liquid crystal display is higher.

In the related art, a Pulse Width Modulation (PWM) dimming method is usually adopted to perform local dimming on the backlight module, and fig. 1 is a schematic diagram illustrating a relationship between an operating current and a brightness of duty ratio dimming. As shown in fig. 1, the abscissa of the figure represents the brightness, the ordinate represents the operating current of the light source, and the pulse width of the operating current represents the duty cycle of the operating current, and as shown in fig. 1, the amplitude of the operating current is constant, and the brightness of the light source is adjusted by changing the duty cycle of the operating current, and 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. The backlight module is dimmed by adopting a duty ratio dimming mode, so that the amplitude of the working current of the light source is constant, and the color consistency of the light source is better.

Fig. 2 is a schematic diagram illustrating the influence of the rise time and the fall time of the operating current on the pulse waveform, as shown in fig. 2, (1) in fig. 2 is an ideal pulse waveform of the operating current, a square wave is taken as an example in the figure, and (2) in fig. 2 is an actual pulse waveform of the operating current, which is influenced by the rise time Tr and the fall time Tf of the operating current, so that the actual pulse waveform of (2) in fig. 2 becomes a trapezoid. As is obvious from comparing (1) and (2) in fig. 2, the rising time Tr and the falling time Tf of the working current affect the pulse width of the working current, so that the duty ratio of the working current is reduced, the brightness of the light source is affected, and the brightness linearity of the light source is poor. Especially, the pulse width of the working current is narrower in low gray scale, and the rising time Tr and the falling time Tf of the working current have more obvious influence on the pulse width, so that the brightness linearity of the light source is worse in low gray scale. Moreover, the rising time Tr and the falling time Tf of the working current cannot be avoided due to the influence of physical wiring, parasitic capacitance, driving capability of the driving chip and the like in the backlight module.

Based on this, in order to improve the brightness linearity of the light source in the backlight module, the embodiment of the present application provides a brightness adjusting method of the backlight module and a related device. The backlight module can be applied to a liquid crystal display device, and is arranged 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, so that the liquid crystal display device can realize image display.

In order to make the objects, technical solutions and advantages of the present application more apparent, the present application will be described in further detail with reference to the accompanying drawings.

It should be noted that in this specification, like reference numerals and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present application. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present application, it should be noted that, unless otherwise explicitly stated or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, a fixed connection, a detachable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in this application will be understood to be a specific case for those of ordinary skill in the art.

Fig. 3 is a schematic structural diagram of a backlight module according to an embodiment of the present application, and as shown in fig. 3, the backlight module may be a direct-type backlight module. The backlight module may include at least one backlight panel 101, at least two light sources 102, at least one driving chip 103, and at least one controller 104. The backlight module may include one backlight panel 101, or the backlight module may also include at least two backlight panels 101 that are spliced to each other. Each light source 102 in the backlight module is fixed on the backlight panel 101, the backlight module is divided into at least two light emitting areas C, at least one light source 102 is arranged in each light emitting area C, the light source 102 may be a micro light emitting diode (mini LED), and of course, the light source 102 may also be other types of light emitting devices, which is not limited herein. The light emitting areas C in the backlight module may be uniformly distributed or non-uniformly distributed, and the light emitting areas C in the backlight module may be divided according to actual needs, which is not limited herein. The upper left square in fig. 3 is a partially enlarged schematic view of a light emitting region C, and when a plurality of light sources 102 are disposed in the light emitting region C, the plurality of light sources 102 may be electrically connected in a multi-serial and multi-parallel manner.

With reference to fig. 3, the driving chips 103 in the backlight module are electrically connected to the backlight panel 101, and the driving chips 103 are sequentially connected in series, and the controller 104 is electrically connected to the driving chips 103. The driving chip 103 includes at least one channel, such as CH1, CH2 \8230 \ 8230:chn, in the embodiment of the present application, the channel may refer to an output port of the driving chip 103, and each channel corresponds to at least one light emitting region C. The controller 104 is configured to provide the driving chip 103 with the luminance gray-scale value required by each light-emitting region C, and the channel is configured to provide the operating current to the light source 102 in the corresponding light-emitting region C. In this way, the driving chip 103 precisely controls the operating current of the light source 102 in each light emitting region C, so as to achieve the purpose of local dimming.

Fig. 4 is a schematic flow chart of a brightness adjustment method of a backlight module according to an embodiment of the present disclosure, where the method may be applied to the system architecture shown in fig. 3, and as shown in fig. 4, the brightness adjustment method according to the embodiment of the present disclosure may be applied to any one of the driver chips shown in fig. 3, and specifically includes:

s201, acquiring brightness gray-scale values of light emitting areas corresponding to channels;

s202, determining a dimming mode corresponding to each channel according to the brightness gray-scale value corresponding to each channel and a preset threshold, and determining the amplitude and duty ratio of the working current output by each channel according to the corresponding relation between the working current of the channel and the brightness gray-scale value under different dimming modes; fig. 5 is a schematic diagram illustrating a relationship between an operating current and a luminance gray scale value in an embodiment of the present application, in which an abscissa represents the luminance gray scale value and an ordinate represents the operating current. As shown in fig. 5, when the luminance gray-scale value corresponding to the channel is smaller than the preset threshold Th, the dimming mode corresponding to the channel is a current dimming mode, the duty ratio of the working current output by the channel remains unchanged, and the amplitude of the working current output by the channel is in a positive correlation with the luminance gray-scale value; when the luminance gray scale value corresponding to the channel is greater than the preset threshold Th, the dimming mode corresponding to the channel is a Pulse Width Modulation (PWM) dimming mode, the amplitude of the working current output by the channel is kept unchanged, and the duty ratio of the working current output by the channel is in a positive correlation with the luminance gray scale value.

According to the brightness adjusting method provided by the embodiment of the application, the dimming mode corresponding to each channel can be determined according to the obtained brightness gray-scale value corresponding to each channel and the preset threshold, the amplitude and the duty ratio of the working current output by each channel can be determined according to the corresponding relation between the working current of the channel and the brightness gray-scale value in different dimming modes, and the regional dimming of the backlight module can be realized. When the luminance gray scale value corresponding to the channel is smaller than the preset threshold value, the dimming mode corresponding to the channel is a current regulation mode, namely the current regulation mode is adopted at a low gray scale, the duty ratio of the working current is kept unchanged, and the luminance of the backlight module is regulated by changing the amplitude of the working current, so that the influence of the rising time and the falling time of the working current on the pulse waveform can be effectively reduced, the influence of wiring parasitic parameters can be reduced, and the luminance linearity of the backlight module at the low gray scale is effectively improved. When the luminance gray scale value corresponding to the channel is larger than the preset threshold value, the dimming mode corresponding to the channel is a PWM dimming mode, namely the PWM dimming mode is adopted under the high gray scale, the amplitude of the working current is kept unchanged, and the luminance of the backlight module is adjusted by changing the duty ratio of the working current. Because the influence of the rise time and the fall time of the working current on the pulse waveform is small under the high gray scale, the brightness linearity of the backlight module is high under the high gray scale, and the color stability of the backlight module can be ensured by adopting a PWM dimming mode under the high gray scale. Therefore, the brightness adjusting method provided by the embodiment of the application can enable the brightness linearity of the backlight module to be higher under the full gray scale.

Referring to fig. 3, in step S201, the luminance grayscale value of the light-emitting region C corresponding to each channel, which is obtained by the driving chip 103, is determined according to the display grayscale value of each corresponding region in the to-be-displayed image of the screen. Specifically, the controller 104 may determine a luminance gray scale value required by a light emitting region corresponding to each channel according to a to-be-displayed picture of the screen, and send the determined luminance gray scale value corresponding to each channel to the corresponding driving chip 103. For example, the to-be-displayed picture of the screen is a picture with a brighter central area and a darker peripheral area, the luminance gray-scale value required by the light-emitting area corresponding to the central area is higher, and the luminance gray-scale value required by the light-emitting area corresponding to the peripheral area is lower. In a specific implementation, the display gray scale value of the to-be-displayed image is different from the luminance gray scale value of the backlight module, for example, the display gray scale value of the to-be-displayed image is generally in a range of 0 to 255, and when the luminance gray scale value occupies 12 bits, the luminance gray scale value of the backlight module is generally in a range of 0 to 4095. The controller 104 can convert the display gray scale value of the to-be-displayed picture into the luminance gray scale value required by each light-emitting area in the backlight module according to the corresponding relationship between the display gray scale value of the to-be-displayed picture and the luminance gray scale value of the backlight module.

In the step S202, a specific value of the preset threshold Th may be determined according to actual needs, for example, a critical value of the backlight module in the related art, where the brightness linearity is significantly reduced, may be used as the preset threshold Th. Optionally, the preset threshold Th may be 128, and of course, the preset threshold may also be other values, which are not limited herein.

Fig. 6 is a schematic diagram illustrating another relationship between the operating current and the luminance gray scale value in the embodiment of the present application, in which the abscissa represents the luminance gray scale value and the ordinate represents the operating current. As shown in fig. 6, a curve L1 in the figure represents a relationship curve between the duty ratio of the operating current and the luminance grayscale value, in which the duty ratio of the operating current is a constant value in the current dimming mode, and the duty ratio of the operating current and the luminance grayscale value are in a positive correlation relationship in the PWM dimming mode, that is, the duty ratio of the operating current increases as the luminance grayscale value increases. The curve L2 represents a relationship curve between the amplitude of the working current and the luminance gray-scale value, in the current dimming mode, the amplitude of the working current is in a positive correlation with the luminance gray-scale value, that is, the amplitude of the working current increases with the increase of the luminance gray-scale value, and in the PWM dimming mode, the amplitude of the working current is a constant value.

Referring to a curve L1 in fig. 6, in the brightness adjustment method provided in the embodiment of the present application, the duty ratio of the operating current output by the channel may be determined as follows:

when the dimming mode corresponding to the channel is the current dimming mode, the duty ratio of the working current output by the channel is the ratio of the preset threshold value to the maximum gray-scale value of the backlight module;

when the dimming mode corresponding to the channel is the PWM dimming mode, the duty ratio of the working current output by the channel is the ratio of the brightness gray-scale value corresponding to the channel to the maximum gray-scale value of the backlight module.

As is apparent from the curve L1 in fig. 6, in the PWM dimming mode, the duty ratio of the working current and the luminance gray-scale value are in a linear relationship, and when the duty ratio of the working current is 100%, the corresponding luminance gray-scale value is the maximum gray-scale value of the backlight module, so that, according to the curve L1, the duty ratio of the working current output by the channel is the ratio of the luminance gray-scale value corresponding to the channel to the maximum gray-scale value of the backlight module. For example, the maximum gray scale value of the backlight module is 4095 at present, and a specific numerical value of the maximum gray scale value of the backlight module is not limited herein. In the current dimming mode, the duty ratio of the working current is kept unchanged along with the change of the brightness gray-scale value, so that in the current dimming mode, the duty ratio of the working current is the duty ratio corresponding to the preset threshold Th, namely the duty ratio of the working current output by the channel is the ratio of the preset threshold to the maximum gray-scale value of the backlight module.

In summary, the duty cycle of the operating current output by the channel can be determined according to the following formula:

wherein PWM represents duty ratio of working current, U represents brightness gray scale value, and U represents brightness gray scale value _max The maximum gray scale value of the backlight module is shown.

In the brightness adjustment method provided in the embodiment of the present application, the amplitude of the working current output by the channel may be determined as follows:

determining a mixed dimming current gain corresponding to the channel according to the brightness gray-scale value and the dimming mode corresponding to the channel;

and determining the amplitude of the working current output by the channel according to the determined mixed dimming current gain corresponding to the channel, and the preset reference current and global current gain corresponding to the driving chip.

Referring to a curve L2 in fig. 6, in the current dimming mode, the amplitude of the operating current increases with an increase of the luminance gray-scale value, and in the PWM dimming mode, the amplitude of the operating current is a fixed value, that is, in different dimming modes, the corresponding relationship between the amplitude of the operating current and the luminance gray-scale value is different, so in the embodiment of the present application, the parameter of the hybrid dimming current gain is used to distinguish the corresponding relationship between the amplitude of the operating current and the luminance gray-scale value in different dimming modes. Specifically, the hybrid dimming current gain is related to the luminance gray-scale value and the dimming mode corresponding to the channel.

FIG. 7 is a schematic diagram illustrating control of the operating current in the embodiment of the present application, as shown in FIG. 7, the reference current I corresponding to the driving chip _ref The current source of the driving chip can be understood, and in specific implementation, the current source can be set through an external resistor of the driving chipOf course, the current source may be set in other manners, for example, the current source may be adjusted by internal parameters of the chip, or an externally provided current source may be used, and the specific setting manner of the current source is not limited herein. Global current Gain ₁ Is a global variable, i.e. drives the global current Gain corresponding to each channel in the chip ₁ The values of (A) are the same. Global current Gain ₁ Means to amplify the reference current I _ref To adjust the overall brightness of the backlight module, i.e. the global current Gain ₁ Is greater than 1, e.g. global current Gain ₁ Is 1000, and represents the reference current I _ref Magnification is 1000 times. Of course, when the reference current I _ref When too large, the global current Gain ₁ May also mean that the reference current I is reduced _ref I.e. global current Gain ₁ The value of (b) may also be less than 1, and is not limited herein. In practical application, the global current Gain can be adjusted ₁ Stored in registers internal to the driver chip, e.g. global current Gain ₁ Can occupy m bits, m is a positive integer, of course, the global current Gain can be set according to actual needs ₁ The size of the occupied position is not limited herein.

With continued reference to FIG. 7, gain is shown ₃ The dimming current Gain represents the hybrid dimming current Gain, and the luminance gray-scale values and the dimming modes corresponding to different channels may be different, so the hybrid dimming current Gain corresponding to different channels ₃ May also be different. According to the reference current I of the driving chip _ref And global current Gain ₁ And a hybrid dimming current Gain corresponding to the channel ₃ The amplitude I of the working current output by the channel can be determined _ch And, the amplitude I of the operating current output by the channel _ch In the range of 0 to I _max In the range of (1), wherein I _max For the maximum amplitude of the operating current, the maximum amplitude I of the operating current may be determined based on performance parameters of the light source _max Preventing amplitude I of the operating current output by the channel _ch Over-burning the light source.

Referring to the curve L2 in fig. 6, in the embodiment of the present application, the hybrid dimming current gain may be determined as follows:

when the dimming mode corresponding to the channel is the current dimming mode, the mixed dimming current gain is the ratio of the brightness gray-scale value to the preset threshold value;

when the dimming mode corresponding to the channel is the PWM dimming mode, the hybrid dimming current gain is 1.

That is, in the embodiment of the present application, the hybrid dimming current gain may be expressed by the following formula:

as is apparent from a curve L2 in fig. 6, in the current dimming mode, the amplitude of the operating current and the luminance gray-scale value are in a linear relationship, and in the PWM dimming mode, the amplitude of the operating current is a constant value. In order to distinguish the corresponding relation between the amplitude of the working current and the luminance gray-scale value in different dimming modes, the values of the gain of the mixed dimming current in different dimming modes are different. Specifically, in the current dimming mode, the hybrid dimming current gain is a ratio of the luminance gray-scale value to a preset threshold, so that the amplitude of the working current and the luminance gray-scale value are in a linear relationship. In the PWM dimming mode, the hybrid dimming current gain is a constant value of 1, so that the amplitude of the operating current can be a constant value. Therefore, in the embodiment of the present application, by setting the parameter of the hybrid dimming current gain, the amplitude of the operating current output by the channel can satisfy the trend shown by the curve S2 in fig. 6.

Due to the influence of factors such as current precision difference of each channel in the driving chip, difference of the light source, parasitic capacitance of signal routing and the like, under the same brightness gray scale, brightness of different light emitting areas can be different, brightness uniformity of each light emitting area in the backlight module is poor, and further display uniformity of the liquid crystal display is poor. Based on this, in order to improve the brightness uniformity of each light-emitting area in the backlight module, in the embodiment of the present application, the brightness of different light-emitting areas is adjusted by setting the local current gain corresponding to each channel. Specifically, the determining the amplitude of the working current output by the channel according to the determined hybrid dimming current gain corresponding to the channel and the preset reference current and global current gain of the driving chip may include:

referring to fig. 7, the hybrid dimming current Gain corresponding to the determined channel ₃ Preset reference current I corresponding to the driving chip _ref And global current Gain ₁ And local current Gain corresponding to the predetermined channel ₂ And determining the amplitude of the working current output by the channel. Local current Gain corresponding to different channels ₂ May be different, and thus, the local current Gain corresponding to the channel may be set ₂ Making the amplitude I of the working current output by the channel _ch It floats within a certain range, for example, it may float within a range of. + -. S%, S > 0. Wherein, the local current Gain ₂ In the range of 0 to (2) ^p In the range of-1), p is the local current Gain ₂ The occupied bit number, p is a positive integer, the value of p can be determined according to the specification of the driver chip, for example, p can be 6, and of course, p can also be other values, which is not limited here. In specific implementation, a plurality of registers corresponding to each channel may be disposed in the driving chip, and the local current Gain corresponding to each channel may be obtained ₂ Respectively stored in corresponding registers.

In the embodiment of the present application, the local current Gain ₂ Value range of (2) to (0) ^p -1), which can correspond to the adjustment range of the amplitude of the working current 1-S% -1 + S%, and in practical application, the local current Gain corresponding to each channel can be determined according to the brightness difference of different light emitting areas ₂ 。

In the embodiment of the application, the local current gain corresponding to each channel is set, so that the brightness uniformity of each light emitting area in the backlight module can be improved, the uniformity of a displayed picture is better when the liquid crystal display displays scenes such as a pure color picture or a large dynamic video, and the display effect is improved.

Fig. 8 is a schematic diagram of a control architecture of an operating current in an embodiment of the present application, and as shown in fig. 8, a magnitude of the operating current output by a channel may satisfy the following formula:

I _ch ＝I _ref *Gain ₁ *Gain ₂ *Gain ₃ ；

wherein, I _ch Representing the amplitude of the operating current output by the channel; i is _ref Representing the reference current corresponding to the driving chip; gain ₁ Representing the corresponding global current gain of the driving chip; gain ₂ Representing the local current gain corresponding to the channel; gain ₃ Indicating the hybrid dimming current gain for the channel.

With continued reference to FIG. 8, the reference current I _ref And global current Gain ₁ Are all preset global variables, i.e. reference currents I corresponding to all channels _ref The same global current Gain corresponding to each channel ₁ The gains are the same. Local current Gain ₂ The local adjustment variable for adjusting the brightness of different light emitting regions can be determined according to the brightness difference of different light emitting regions, so that the local current Gain corresponding to different channels ₂ May be different. Hybrid dimming current Gain ₃ Is used for distinguishing different dimming modes and is determined by the brightness gray-scale value corresponding to the channels and the preset threshold value, therefore, the mixed dimming current Gain corresponding to different channels ₃ May also be different. According to the reference current I _ref Global current Gain ₁ Local current Gain ₂ And hybrid dimming current Gain ₃ The amplitude Ich of the operating current of each channel can be determined ₁ 、Ich ₂ ……Ich _n 。

Optionally, a processor may be disposed in the driver chip, the processor is configured to execute the brightness adjustment method, fig. 9 is a schematic diagram of an operating principle of the processor in an embodiment of the present application, as shown in fig. 9, a processor 1031 obtains brightness grayscale values required by the light-emitting regions corresponding to the channels, and the processor 1031 calls the global current Gain stored in the register ₁ And local current Gain corresponding to each channel ₂ The processor 1031 outputs the luminance gray corresponding to each channelThe step value and the preset threshold value determine the dimming mode corresponding to each channel, and further determine the mixed dimming current Gain corresponding to each channel ₃ Then, the processor 1031 determines and outputs the duty ratio and the amplitude of the operating current corresponding to each channel.

In the embodiment of the application, the local current gain corresponding to each channel can be determined by a brightness uniformity calibration method of the backlight module. The brightness uniformity calibration method can be executed in the testing process of the backlight module before the backlight module leaves factory, and the brightness calibration method can be executed in external testing equipment. Fig. 10 is a schematic flowchart illustrating a method for calibrating luminance uniformity of a backlight module according to an embodiment of the present disclosure, as shown in fig. 10, the method for calibrating luminance uniformity of a backlight module according to an embodiment of the present disclosure may include:

s301, setting the local current gain corresponding to each channel to be the same initial value, for example, the initial value may be 0, and certainly, the initial value may also be other values, which is not limited herein;

s302, electrifying the backlight module to light each light source in the backlight module;

s303, acquiring the brightness of each light emitting area in the backlight module, and optionally, photographing the backlight module through a camera to identify the brightness of each light emitting area in the backlight module;

s304, judging whether the brightness uniformity of the backlight module is larger than a% of a first threshold value, wherein a is larger than 0; if yes, go to step S306; if not, executing step S305; in the embodiment of the application, whether the brightness uniformity of the backlight module is larger than a% or not can be determined by adjusting the local current gain to calibrate the brightness uniformity of the backlight module. 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, so that the backlight module with the brightness uniformity less than a% is abandoned, and the local current gain corresponding to the backlight module with the brightness uniformity more than a% is adjusted; in an implementation, a specific value of a may be determined according to the local current adjusting capability of the driving chip, for example, if the local current adjusting capability of the driving chip is 90% to 110% (i.e., the parameter S = 10), a may be set to 80, that is, if the luminance difference of each light emitting region in the backlight module exceeds 20%, the luminance uniformity of the backlight module is difficult to adjust, and the backlight module needs to be discarded.

S305, discarding the backlight module with the brightness uniformity smaller than a% of a first threshold value;

s306, adjusting local current gains corresponding to the channels; specifically, the average brightness value of each light-emitting area in the backlight module is obtained, the average brightness value of each light-emitting area in the backlight module is used as a target brightness value, the local current gain corresponding to each channel is adjusted according to the target brightness value, and then the adjusted local current gain corresponding to each channel is written into a nonvolatile memory inside the driving chip, and the local current gains corresponding to each channel may be different. In the embodiment of the application, the average brightness value of each light-emitting area is used as the target brightness value, and compared with the use of other values as the target brightness value, the local current gain can be adjusted within the range of +/-S%, and the adjustment range of the local current gain can be reduced, so that the variation of the amplitude of the working current is reduced, and the phenomenon that the color and brightness of the light-emitting area are changed too much due to the overlarge variation of the amplitude of the working current is avoided.

S307, electrifying the backlight module to lighten each light source in the backlight module;

s308, acquiring the brightness of each light-emitting area in the backlight module, and optionally, photographing the backlight module through a camera to identify the brightness of each light-emitting area in the backlight module;

s309, judging whether the brightness uniformity of the backlight module is larger than a second threshold value b%, wherein the second threshold value is larger than the first threshold value, namely b% is larger than a%, for example, b can be 95; if yes, go to step S310; if not, returning to the step S306; in the embodiment of the application, after the local current gains corresponding to the channels are adjusted, whether the brightness uniformity of the backlight module meets the requirement of the brightness uniformity can be determined by judging whether the brightness uniformity of the backlight module is greater than b%, if so, the brightness uniformity calibration of the backlight module is completed, and if not, the local current gains corresponding to the channels are continued until the backlight module meets the requirement of the brightness uniformity;

s310, completing the brightness uniformity calibration of the backlight module, namely completing the adjustment of the local current gain corresponding to each channel.

And after the brightness uniformity of the backlight module is calibrated, solidifying the adjusted local current gain corresponding to each channel into a nonvolatile memory in the driving chip. Therefore, in the using process of the liquid crystal display, each time the driving chip is electrified, parameters such as the global current gain and the local current gain corresponding to each channel can be directly called, the driving chip can control each channel to output the working current only by acquiring the brightness gray-scale value sent by the controller, and the control mode is simple.

Fig. 11 is a comparison diagram of brightness uniformity of the backlight module before and after calibration, as shown in fig. 11, (1) in fig. 11 is brightness data of each light-emitting region in the backlight module before calibration, (2) in fig. 11 is local current gain corresponding to each channel after adjustment, and (3) in fig. 11 is brightness data of each light-emitting region in the backlight module after calibration. As shown in fig. 11 (1), the luminance uniformity of the backlight module before calibration is about 82.9%, and the area enclosed by the dotted line in the figure is an area with poor luminance uniformity, and after the local current gain corresponding to each channel is adjusted, as shown in fig. 11 (3), the luminance uniformity of the backlight module after calibration is about 97.2%. Fig. 11 shows that the brightness uniformity of the backlight module can be better improved by the brightness adjusting method provided in the embodiment of the present application.

Fig. 12 is a schematic diagram illustrating the contrast between the luminance linearity of the backlight module according to the related art and the luminance linearity of the backlight module according to the embodiment of the present application, where (1) in fig. 12 is a luminance linearity curve of the backlight module obtained by only using PWM dimming in the related art, and (2) in fig. 12 is a luminance linearity curve of the backlight module obtained by using hybrid dimming in the embodiment of the present application, and in (1) and (2) of fig. 12, the abscissa represents the luminance gray-scale value and the ordinate represents the luminance value. Comparing (1) and (2) in fig. 12, compared with the duty ratio dimming method adopted in the related art, the hybrid dimming method is adopted in the embodiment of the present application, and when the luminance gray-scale value is smaller than the preset threshold Th, that is, under the low gray-scale, the luminance linearity of the backlight module is significantly improved, and the hybrid dimming method is adopted in the embodiment of the present application, the luminance linearity of the backlight module at the full gray-scale is higher.

As shown in fig. 12 (2), the lower right corner is a pulse diagram of the operating current in the embodiment of the present application, where the dotted line represents an ideal waveform of the operating current, and the solid line represents an actual waveform of the operating current. As is apparent from (2) in fig. 12, the actual waveform of the operating current in the embodiment of the present application is less different from the ideal waveform. The current regulation mode is adopted in the low gray scale, the duty ratio of the working current is kept unchanged, and the brightness of the backlight module is regulated by changing the amplitude of the working current, so that the influence of the rising time and the falling time of the working current on the pulse waveform can be reduced, and the difference between the actual waveform and the ideal waveform of the working circuit is small. And moreover, duty ratio regulation is adopted under high gray scale, and the brightness of the backlight module is regulated by changing the duty ratio of the working current, at the moment, the duty ratio of the working current is larger, and the difference between the actual waveform and the ideal waveform of the working current is smaller.

Based on the same technical concept, the embodiment of the application further provides a driving chip, which includes at least one channel, and the channel is used for providing an operating current to a light source in at least one light emitting area in the backlight module. The driving chip provided by the embodiment of the application may further include: a memory and a processor. Wherein the memory stores program instructions; the processor is configured to call the program instruction stored in the memory, and execute the method flow shown in fig. 4 or fig. 10 according to the obtained program, which is not described repeatedly here.

Based on the same technical concept, an embodiment of the present application further provides a backlight module, as shown in fig. 3, the backlight module may include: the backlight module comprises 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 driving chip 103, wherein at least one light source 102 is arranged in each light emitting area C; the driving chip 103 is electrically connected to the backlight panel 101, and the driving chip 103 includes at least one channel, such as CH1, CH2 \8230; CHn, for providing an operating current to the light source 102 in at least one light-emitting region C.

Based on the same technical concept, the embodiment of the present application further provides a display device, including: the backlight module is positioned 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, so that the display device realizes image display. The display device can be any device with a display function, such as a television, a mobile phone, a tablet computer and the like.

Based on the same technical concept, embodiments of the present application further provide a storage medium storing computer-executable instructions for causing a computer to execute any one of the brightness adjustment methods shown in fig. 4 or fig. 10.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may 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, and so forth) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may 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, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

According to the brightness gray-scale value and the preset threshold value corresponding to each channel, the dimming mode corresponding to each channel can be determined, and the amplitude and the duty ratio of the working current output by each channel can be determined according to the brightness gray-scale value and the dimming mode corresponding to each channel, so that the regional dimming of the backlight module is realized. The current regulation mode is adopted under the low gray scale, the duty ratio of the working current is kept unchanged, and the brightness of the backlight module is regulated by changing the amplitude of the working current, so that the influence of the rise time and the fall time of the working current on the pulse waveform is reduced, the influence of wiring parasitic parameters is reduced, and the brightness linearity of the backlight module under the low gray scale is greatly improved. And a PWM dimming mode is adopted under a high gray scale, the amplitude of the working current is kept unchanged, and the brightness of the backlight module is adjusted by changing the duty ratio of the working current. The influence of the rise time and the fall time of the working current on the pulse waveform is small under the high gray scale, so that the brightness linearity of the backlight module is high under the high gray scale, and the color stability of the backlight module is ensured by adopting a PWM dimming mode under the high gray scale. Therefore, the brightness adjusting method provided by the embodiment of the application can enable the brightness linearity of the backlight module to be higher under the full gray scale. In addition, in the embodiment of the application, 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 uniformity of a displayed picture of the liquid crystal display is better in scenes such as displaying pure-color pictures or large dynamic videos, and the display effect is improved.

While the preferred embodiments of the present application have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all alterations and modifications as fall within the scope of the application.

It will be apparent to those skilled in the art that various changes and modifications can be made in the embodiments of the present application without departing from the spirit and scope of the embodiments of the present application. Thus, if such modifications and variations of the embodiments of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to encompass such modifications and variations.

Claims

1. The method for adjusting the brightness of the backlight module is characterized in that the backlight module comprises at least two light sources and at least one driving chip; the backlight module is divided into at least two light emitting areas, and at least one light source is arranged in each light emitting area; the driving chip comprises at least one channel, and the channel is used for providing working current for the light source in at least one light emitting area;

the brightness adjusting method is applied to the driving chip and comprises the following steps:

acquiring the brightness gray-scale value of the 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, and determining the amplitude and duty ratio of the working current output by each channel according to the corresponding relation between the working current of the channel and the brightness gray-scale value under different dimming modes; when the brightness gray-scale value corresponding to the channel is smaller than the preset threshold value, the dimming mode corresponding to the channel is a current dimming mode, the duty ratio of the working current output by the channel is kept unchanged, and the amplitude of the working current output by the channel is in a positive correlation with the brightness gray-scale value; when the luminance gray scale value that the passageway corresponds is greater than when presetting the threshold value, the mode of adjusting luminance that the passageway corresponds is pulse width PWM mode of adjusting luminance, the amplitude of the working current of passageway output remains unchanged, the duty cycle of the working current of passageway output is positive correlation's relation with luminance gray scale value.

2. The brightness adjustment method according to claim 1, wherein the duty ratio of the operating current outputted from the channel is determined as follows:

when the dimming mode corresponding to the channel is a current dimming mode, the duty ratio of the working current output by the channel is the ratio of the preset threshold value to the maximum gray-scale value of the backlight module;

and when the dimming mode corresponding to the channel is the PWM dimming mode, the duty ratio of the working current output by the channel is the ratio of the brightness gray-scale value corresponding to the channel to the maximum gray-scale value of the backlight module.

3. The brightness adjustment method according to claim 1, wherein the amplitude of the operating current outputted from the channel is determined as follows:

determining a mixed dimming current gain corresponding to the channel according to the brightness gray-scale value corresponding to the channel and the dimming mode;

and determining the amplitude of the working current output by the channel according to the determined mixed dimming current gain corresponding to the channel and the preset reference current and global current gain corresponding to the driving chip.

4. The brightness adjustment method according to claim 3, wherein the hybrid dimming current gain is determined as follows:

when the dimming mode corresponding to the channel is a current dimming mode, the mixed dimming current gain is the ratio of the brightness gray-scale value to the preset threshold value;

and when the dimming mode corresponding to the channel is the PWM dimming mode, the gain of the mixed dimming current is 1.

5. The method of claim 3, wherein the determining the amplitude of the operating current output by the channel according to the determined hybrid dimming current gain corresponding to the channel and the preset reference current and global current gain of the driver chip comprises:

determining the amplitude of the working current output by the channel according to the determined mixed dimming current gain corresponding to the channel, the preset reference current and global current gain corresponding to the driving chip and the preset local current gain corresponding to the channel; wherein the local current gain is in the range of 0 to (2) ^p -1), p is the number of bits occupied by the local current gain, and p is a positive integer.

6. The brightness adjustment method of claim 5, wherein the amplitude of the operating current output by the channel is determined according to the following formula:

I _ch ＝I _ref *Gain ₁ *Gain ₂ *Gain ₃ ；

wherein, I _ch Representing the amplitude of the operating current output by the channel; I.C. A _ref Representing the reference current corresponding to the driving chip; gain ₁ Representing the corresponding global current gain of the driving chip; gain ₂ Representing the local current gain corresponding to the channel; gain ₃ Representing the hybrid dimming current gain corresponding to the channel.

7. The luminance adjustment method according to claim 5 or 6, wherein the local current gain corresponding to each of the channels is determined in the following manner:

setting the local current gain corresponding to each channel to be the same initial value, and electrifying the backlight module to light each light source in the backlight module;

collecting the brightness of each light-emitting area in the backlight module;

judging whether the brightness uniformity of the backlight module is greater than a first threshold value or not; if yes, adjusting the local current gain corresponding to each channel; if not, discarding the backlight module with the brightness uniformity smaller than the first threshold value;

after the local current gain corresponding to each channel is adjusted, the backlight module is electrified again so as to light each light source in the backlight module;

collecting the brightness of each light-emitting area in the backlight module;

judging whether the brightness uniformity of the backlight module is greater than a second threshold value, wherein the second threshold value is greater than the first threshold value; if yes, adjusting local current gain corresponding to each channel; if not, the local current gain corresponding to each channel is continuously adjusted.

8. The method of claim 7, wherein said adjusting the local current gain for each of the channels comprises:

and adjusting the local current gain corresponding to each channel according to the target brightness value by taking the brightness average value of each light-emitting area in the backlight module as the target brightness value.

9. The driving chip is characterized by comprising at least one channel, wherein the channel is used for providing working current for a light source in at least one light-emitting area in a backlight module;

the driving chip further comprises:

a memory for storing program instructions;

a processor for calling the program instructions stored in the memory, executing according to the obtained program:

10. The driver chip of claim 9, wherein the processor determines the duty cycle of the operating current output by the channel by:

11. The driver chip of claim 9, wherein the processor determines the magnitude of the operating current output by the channel by:

12. The driver chip of claim 11, wherein the processor determines the hybrid dimming current gain by:

13. The driver chip of claim 11, wherein the processor determines the amplitude of the operating current output by the channel according to the determined hybrid dimming current gain corresponding to the channel, and a preset reference current and a preset global current gain of the driver chip, and includes:

determining the amplitude of the working current output by the channel according to the determined mixed dimming current gain corresponding to the channel, the preset reference current and global current gain corresponding to the driving chip and the preset local current gain corresponding to the channel; wherein the local current gain is between 0 and (2) ^p -1), p being the number of bits occupied by said local current gain.

14. The driver chip of claim 13, wherein the processor determines the magnitude of the operating current output by the channel according to the following equation:

I _ch ＝I _ref *Gain ₁ *Gain ₂ *Gain ₃ ；

wherein, I _ch Representing the amplitude of the operating current output by the channel; i is _ref Representing the reference current corresponding to the driving chip; gain ₁ Representing the corresponding global current gain of the driving chip; gain ₂ Representing the local current gain corresponding to the channel; gain ₃ And representing the mixed dimming current gain corresponding to the channel.

15. A backlight module, comprising: at least two light emitting areas, a backlight panel, at least two light sources fixed on the backlight panel, and the driving chip of any one of claims 7 to 12; at least one light source is arranged in each light-emitting area;

the driving chip is electrically connected with the backlight panel, and the driving chip comprises at least one channel which is used for providing working current for the light source in at least one luminous area.

16. A display device, comprising: a liquid crystal display panel and the backlight module according to claim 15;

the backlight module is positioned on one side of the light incident surface of the liquid crystal display panel.

17. A storage medium storing computer-executable instructions for causing a computer to execute the brightness adjustment method according to any one of claims 1 to 6.