Backlight brightness adjustment circuit, control method and apparatus thereof

Abstract

This application provides a backlight brightness adjustment circuit and its control method and device. The circuit includes: a first switching component control terminal connected to an AND gate output terminal; one end of the first switching component connected to one end of a first resistor; the other end of the first switching component grounded; the other end of the first resistor connected to a first input terminal of a voltage comparator, one end of a second switching component, and one end of a second resistor; the other end of the second resistor grounded; a second input terminal of the voltage comparator connected to a power supply; the output terminal of the voltage comparator connected to the control terminal of the second switching component; the other end of the second switching component connected to an LED array and one end of a pull-up resistor; the other end of the pull-up resistor connected to a power supply; a first input terminal of the AND gate connected to a controller; and a second input terminal of the AND gate connected to a liquid crystal display screen, used to control the operating state of the first switching component according to the pulse width modulation signal output by the controller and the liquid crystal display screen. This application achieves stepless adjustment of backlight brightness, improving the backlight brightness adjustment experience.

Description

Technical Field

[0001] This application relates to the field of brightness adjustment technology, and in particular to a backlight brightness adjustment circuit and its control method and device. Background Technology

[0002] A liquid crystal display (LCD) is a type of display that uses light-emitting diodes (LEDs) as its backlight. In applications, when an LCD screen (not with black insertion) displays images, each sub-pixel on the screen controls the deflection of the liquid crystal according to different voltage signals based on the changes in each frame. However, the deflection of the liquid crystal takes a certain amount of time. When the data refresh rate is too fast, the liquid crystal may not have enough time to react; that is, the backlight may be turned on before the liquid crystal has completed its deflection, resulting in visible ghosting on the LCD screen.

[0003] To reduce ghosting on LCD screens, black insertion is employed. This allows the backlight to be turned off during data transmission and liquid crystal deflection for each frame, and turned on again when data transmission and deflection are complete. When displaying data using an LCD screen with black insertion, users may need to adjust the backlight brightness depending on the ambient light. Currently, backlight brightness adjustment includes manual and automatic adjustments. Both methods divide the backlight brightness into multiple levels, and for each brightness level, the system brightness adjustment control is divided into multiple ranges to establish a mapping between brightness levels and these ranges. When a user manually adjusts the backlight brightness, they slide the slider on the system brightness adjustment control to a specific range, adjusting the LCD screen's backlight brightness to the corresponding level.

[0004] However, the above-mentioned backlight brightness adjustment method has the same mapping relationship between backlight brightness level and value range for different users' devices, but each user's adjustment needs for backlight brightness are different, which leads to users being dissatisfied with the adjusted backlight brightness and resulting in a poor user experience. Summary of the Invention

[0005] This application provides a backlight brightness adjustment circuit and its control method and device, which realizes stepless adjustment of backlight brightness, thereby improving user satisfaction with backlight brightness adjustment and enhancing user experience.

[0006] In a first aspect, this application provides a backlight brightness adjustment circuit, including: an AND gate circuit, a first switching component, a second switching component, a first resistor, a second resistor, a voltage comparator, an LED array, and a pull-up resistor;

[0007] The control terminal of the first switch assembly is connected to the output terminal of the AND gate circuit, one end of the first switch assembly is connected to one end of the first resistor, and the other end of the first switch assembly is grounded.

[0008] The other end of the first resistor is connected to the first input terminal of the voltage comparator, one end of the second switching assembly, and one end of the second resistor, while the other end of the second resistor is grounded.

[0009] The second input terminal of the voltage comparator is connected to the power supply, and the output terminal of the voltage comparator is connected to the control terminal of the second switching assembly.

[0010] The other end of the second switching assembly is connected to the LED array and one end of the pull-up resistor, and the other end of the pull-up resistor is connected to the power supply.

[0011] The first input terminal of the AND gate circuit is connected to the controller, and the second input terminal of the AND gate circuit is connected to the liquid crystal display screen. It is used to control the working state of the first switching component according to the first pulse width modulation signal output by the controller and the second pulse width modulation signal output by the liquid crystal display screen.

[0012] The first pulse width modulation signal is generated based on the current brightness value of the backlight of the liquid crystal display screen, and the frequency of the first pulse width modulation signal is greater than the frequency of the second pulse width modulation signal.

[0013] Secondly, embodiments of this application provide a backlight brightness adjustment circuit control method, including:

[0014] Based on the received backlight brightness adjustment command, obtain the current brightness value of the system brightness adjustment control;

[0015] Based on the current brightness value, determine the duty cycle of the pulse width modulation signal that drives the backlight of the liquid crystal display screen, and use the pulse width modulation signal as the first pulse width modulation signal;

[0016] The operating state of the switching component connected to the backlight of the liquid crystal display is controlled according to the first pulse width modulation signal and the second pulse width modulation signal output by the liquid crystal display, so as to adjust the backlight brightness of the liquid crystal display.

[0017] The frequency of the first pulse width modulation signal is greater than the frequency of the second pulse width modulation signal.

[0018] Thirdly, embodiments of this application provide an electronic device including any of the backlight brightness adjustment circuits described in the first aspect embodiments.

[0019] The technical solutions disclosed in this application have the following beneficial effects:

[0020] By setting an AND gate circuit, a first switch component, a second switch component, a first resistor, a second resistor, a voltage comparator, and a pull-up resistor in the backlight brightness adjustment circuit of the screen, and controlling whether the first resistor is connected to the backlight brightness adjustment circuit according to the pulse width modulation signal output by the controller and the LCD screen, the backlight current of the screen can be adjusted by adjusting the size of the current limiting resistor in the backlight brightness adjustment circuit. This achieves stepless adjustment of the backlight brightness, thereby improving user satisfaction with the backlight brightness adjustment and enhancing the user experience. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic block diagram of a backlight brightness adjustment circuit provided in an embodiment of this application;

[0023] Figure 2 This is a schematic block diagram of another backlight brightness adjustment circuit provided in the embodiments of this application;

[0024] Figure 3 This is a schematic block diagram of another backlight brightness adjustment circuit provided in the embodiments of this application;

[0025] Figure 4 This is a schematic block diagram of another backlight brightness adjustment circuit provided in the embodiments of this application;

[0026] Figure 5 This is a schematic flowchart of a backlight brightness adjustment circuit control method provided in an embodiment of this application;

[0027] Figure 6 This is a schematic flowchart of another backlight brightness adjustment circuit control method provided in the embodiments of this application;

[0028] Figure 7 This is a schematic flowchart of another backlight brightness adjustment circuit control method provided in the embodiments of this application;

[0029] Figure 8 This is a schematic block diagram of an electronic device provided in an embodiment of this application. Detailed Implementation

[0030] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0031] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or server that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or devices.

[0032] This application applies to backlight brightness adjustment of liquid crystal displays (LCDs) with black pixel insertion functionality. Specifically, when adjusting the backlight brightness of an LCD screen with black pixel insertion, the user slides a slider on the system's brightness adjustment control to a specific range. This causes the LCD screen to adjust the backlight brightness to the level corresponding to that range, based on a pre-established mapping relationship between backlight brightness levels and ranges. However, while the mapping relationship between backlight brightness levels and ranges is the same for different users' devices, each user's adjustment needs are different. This can lead to user dissatisfaction with the adjusted backlight brightness, resulting in a poor user experience. Therefore, this application provides a circuit that can adjust the backlight brightness specifically according to the user's needs, satisfying the user's personalized backlight brightness adjustment requirements and achieving stepless backlight brightness adjustment. This improves user satisfaction with backlight brightness adjustment and enhances the user experience.

[0033] The following is a detailed description of a backlight brightness adjustment circuit provided in an embodiment of this application, with reference to the accompanying drawings.

[0034] Figure 1 This is a schematic block diagram of a backlight brightness adjustment circuit provided in an embodiment of this application.

[0035] like Figure 1As shown, the backlight brightness adjustment circuit 100 of this application may include: AND gate circuit 11, first switch assembly 12, second switch assembly 13, first resistor 14, second resistor 15, voltage comparator 16, LED array 17 and pull-up resistor 18.

[0036] The control terminal of the first switch assembly 12 is connected to the output terminal of the AND gate circuit 11, one end of the first switch assembly 12 is connected to one end of the first resistor 14, and the other end of the first switch assembly 12 is grounded.

[0037] The other end of the first resistor 14 is connected to the first input terminal of the voltage comparator 16, one end of the second switching assembly 13 and one end of the second resistor 15, and the other end of the second resistor 15 is grounded;

[0038] The second input terminal of the voltage comparator 16 is connected to the power supply, and the output terminal of the voltage comparator 16 is connected to the control terminal of the second switching assembly 13.

[0039] The other end of the second switch assembly 13 is connected to the LED array 17 and one end of the pull-up resistor 18, and the other end of the pull-up resistor 18 is connected to the power supply.

[0040] The first input terminal of the AND gate circuit 11 is connected to the controller, and the second input terminal of the AND gate circuit 11 is connected to the liquid crystal display screen. It is used to control the working state of the first switching component 12 according to the first pulse width modulation signal output by the controller and the second pulse width modulation signal output by the liquid crystal display screen.

[0041] The first pulse width modulation signal is generated based on the current brightness value of the backlight of the liquid crystal display screen, and the frequency of the first pulse width modulation signal is greater than the frequency of the second pulse width modulation signal.

[0042] In this embodiment of the application, the pulse width modulation signal is specifically a PWM (Pulse Width Modulation) signal.

[0043] The frequency of the first pulse width modulation signal is usually hundreds or even thousands of times higher than that of the second pulse width modulation signal, and it is used to control the backlight brightness of the liquid crystal display (LCD).

[0044] The frequency of the second pulse width modulation signal is the same as the image refresh rate. For example, if the image refresh rate is 72 Hz, 90 Hz, 120 Hz, or other, then the frequency of the second pulse width modulation signal is 72 Hz, 90 Hz, 120 Hz, or other.

[0045] Furthermore, the second pulse width modulation signal is used to control the backlight on / off state of the LCD screen to achieve the black insertion function of the LCD screen.

[0046] In specific implementation, when the controller receives a backlight brightness adjustment operation triggered by the user on the LCD screen, the controller generates a first pulse width modulation (PWM) signal corresponding to the current brightness value based on the adjustment operation. Furthermore, the LCD screen automatically generates a second PWM signal with a frequency lower than the first PWM signal, based on the image refresh rate. Then, the controller sends the generated first PWM signal to AND gate 11, and the LCD screen also sends the generated second PWM signal to AND gate 11, allowing AND gate 11 to determine the output result based on the first and second PWM signals. The output result is either a high level or a low level.

[0047] After receiving the first pulse width modulation signal and the second pulse width modulation signal, AND gate 11 can determine whether both signals are high. If both signals are high, AND gate 11 outputs a high level; otherwise, it outputs a low level. When AND gate 11 outputs a high level, the first switching component 12 connected to it is turned on, connecting the first resistor 14 to the backlight brightness adjustment circuit 100. The duration of the high-level signal is controlled by the length of time the first resistor 14 is connected to the backlight brightness adjustment circuit 100. In other words, the on-time of the first switching component 12 is controlled.

[0048] When the first resistor 14 is connected to the backlight brightness adjustment circuit 100, it forms a parallel structure with the second resistor 15, thus reducing the total current-limiting resistor in the backlight brightness adjustment circuit 100. The duration for which the first resistor 14 is connected to the backlight brightness adjustment circuit 100 is determined by the high-level time. A longer high-level time results in a longer connection time for the first resistor 14, leading to a larger current flowing to the total current-limiting resistor. Consequently, the power supply current flowing to each LED in the LED array 17 through the second switching component 13 also increases, resulting in a brighter LED in the LED array 17. Similarly, a shorter high-level time results in a shorter connection time for the first resistor 14, a smaller current flowing to the total current-limiting resistor, and consequently, a smaller power supply current flowing to each LED in the LED array 17 through the second switching component 13. Consequently, the brightness of each LED in the LED array 17 decreases accordingly.

[0049] In other words, this embodiment of the application controls whether the first resistor 14 is connected to the backlight brightness adjustment circuit 100 and controls the connection time of the first resistor 14, thereby adjusting the current-limiting resistor in the backlight brightness adjustment circuit 100, and adjusting the screen backlight current based on the adjusted current-limiting resistor. This achieves stepless adjustment of the backlight brightness by adjusting the current, thereby improving user satisfaction with backlight brightness adjustment and enhancing the user experience.

[0050] In this embodiment, the duty cycle of the first pulse width modulation signal generated by the controller changes according to the current brightness value corresponding to the backlight brightness adjustment operation sent by the user. For example, if the current brightness value is 120 nits, the duty cycle of the first pulse width modulation signal generated by the controller based on the current brightness value of 120 nits can be 47.27%, etc.

[0051] In other words, the controller in this application can generate first pulse width modulation signals with different duty cycles based on the current brightness value corresponding to the backlight brightness adjustment operation. The backlight brightness adjustment circuit then adjusts the backlight brightness according to these first pulse width modulation signals with different duty cycles. Specifically, the higher the duty cycle, the smaller the current-limiting resistor, the greater the current to the screen backlight, and the brighter the backlight.

[0052] The controller generates the first pulse width modulation signal based on the current brightness value corresponding to the backlight brightness adjustment operation. This can be done by querying the mapping relationship between the first pulse width signal and the brightness value based on the current brightness value, or by directly generating the first pulse width signal based on the current brightness value, etc. No restrictions are placed on this method. The specific implementation process will be described in detail in the following embodiments, and will not be elaborated further here.

[0053] In this embodiment, the first switching component 12 is a metal-oxide-semiconductor field-effect transistor.

[0054] In addition, the second switching component 13 is a transistor.

[0055] Considering that the LCD screen is backlit by multiple LEDs, the LED array 17 in this embodiment includes at least one LED.

[0056] Furthermore, to ensure that the LCD screen still has a black-insertion function when the output of AND gate 11 is low, thereby reducing screen ghosting and causing dizziness to the user, the backlight brightness adjustment circuit 100 provided in this embodiment further includes: a third switch assembly 19, a third resistor 20, and a fourth resistor 21, specifically as follows: Figure 2 As shown.

[0057] Wherein, one end of the third switch assembly 19 is connected to one end of the third resistor 20, the other end of the third switch assembly 19 is connected to the power supply, and the control terminal of the third switch assembly 19 is connected to the output terminal of the liquid crystal display screen;

[0058] The other end of the third resistor 20 is connected to the second input terminal of the voltage comparator 16 and one end of the fourth resistor 21;

[0059] The other end of the fourth resistor 21 is grounded.

[0060] In this embodiment, the third switching component 19 is a metal-oxide-semiconductor field-effect transistor.

[0061] Specifically, when no user-triggered backlight brightness adjustment operation is received, the LCD screen automatically generates a second pulse width modulation signal based on the image refresh rate and sends the second pulse width modulation signal to the third switching component 19. When the second pulse width modulation signal is high, the third switching component 19 is turned on to connect power to the backlight brightness adjustment circuit 100. Furthermore, the power supply voltage is divided by the third resistor 20 and the fourth resistor 21, and the divided voltage is used as the second input terminal (non-inverting input terminal) of the voltage comparator 16. The voltage comparator 16 compares the voltages at the first input terminal (inverting input terminal) and the second input terminal (non-inverting input terminal) to determine whether the output terminal outputs a high level or a low level. When the voltage comparator 16 outputs a high level, it indicates that the LCD screen is currently in image display mode, and at this time, each LED in the LED array 17 is turned on. When the voltage comparator 16 outputs a low level, it indicates that the LCD screen is currently in image refresh mode, and at this time, each LED in the LED array 17 is turned off, and the liquid crystal is deflected, thereby turning off the backlight when the liquid crystal is deflected, thus eliminating the ghosting that appears on the LCD screen.

[0062] like Figure 3 As shown, the backlight brightness adjustment circuit 100 provided in this application embodiment further includes a current-limiting resistor 22 connected in series between the voltage comparator 16 and the second switching component 13.

[0063] In a specific implementation, one end of the current-limiting resistor 22 is connected to the output terminal of the voltage comparator 16, and the other end of the current-limiting resistor 22 is connected to the control terminal of the second switching assembly 13.

[0064] In this embodiment of the application, by connecting a current-limiting resistor 22 in series between the voltage comparator 16 and the second switching component 13 in the backlight brightness adjustment circuit 100, it is possible to avoid the voltage comparator 16 outputting too high, which would cause the second switching component 13 to malfunction or even burn out, thereby reducing unnecessary safety risks.

[0065] Furthermore, the backlight brightness adjustment circuit 100 provided in this application embodiment also includes: a diode 23, specifically as follows: Figure 4 As shown.

[0066] The anode of the diode 23 is connected to the other end of the pull-up resistor 18;

[0067] The cathode of the diode 23 is connected to the other end of the LED array 17 and the second switching assembly 12.

[0068] Specifically, by adding a diode 23 between the pull-up resistor 18, the LED array 17, and the second switching assembly 12, the diode 23 is used to detect whether the LED array 17 is working properly.

[0069] The backlight brightness adjustment circuit provided in this application sets up an AND gate circuit, a first switch component, a second switch component, a first resistor, a second resistor, a voltage comparator, and a pull-up resistor in the backlight brightness adjustment circuit of the screen. According to the pulse width modulation signal output by the controller and the liquid crystal display, the first resistor is controlled to be connected to the backlight brightness adjustment circuit. By adjusting the size of the current limiting resistor in the backlight brightness adjustment circuit, the current of the screen backlight is adjusted, thereby realizing stepless adjustment of the backlight brightness, thereby improving the user's satisfaction with the backlight brightness adjustment and enhancing the user experience.

[0070] Figure 5 This is a schematic flowchart illustrating a backlight brightness adjustment circuit control method provided in an embodiment of this application. The backlight brightness adjustment circuit control method provided in this application can be applied to the backlight brightness adjustment circuit of the above embodiments. Figure 5 As shown, the backlight brightness adjustment circuit control method includes the following steps:

[0071] S101, based on the received backlight brightness adjustment command, obtain the current brightness value of the system brightness adjustment control.

[0072] When using electronic devices, if the screen backlight is too dim or too bright, it will affect the user's viewing experience. Therefore, when the screen backlight brightness is unsuitable for viewing, the user can send a backlight brightness adjustment command to the electronic device, which will then adjust the backlight brightness accordingly.

[0073] As an optional implementation, the backlight brightness adjustment command can be received in the following way:

[0074] Method 1

[0075] Receives backlight brightness adjustment commands triggered by the user via the controller.

[0076] When the electronic device is a VR device, the screen is only used to display images and cannot support user touch operations. Therefore, to meet the user's input needs, the VR device uses an external device, such as a VR controller, allowing the user to perform input operations through the VR controller. The VR controller can be a wireless controller or a wired controller. When the VR controller is a wireless controller, it can be a Bluetooth controller, etc., without specific limitations here.

[0077] In other words, when a user needs to adjust the screen's backlight brightness, they can send a backlight brightness adjustment command via a controller on the electronic device, based on the content displayed on the screen. For example, they can send a backlight brightness adjustment command by triggering the settings button on the controller used to adjust the backlight brightness.

[0078] It should be noted that when the electronic device is another device, and the setting is compatible with an LCD screen and gamepad that support user touch, the user can trigger the background brightness adjustment command through the gamepad or by touching the LCD screen; there are no restrictions on this.

[0079] Method 2

[0080] If the user's gesture indicates that the user is adjusting the backlight brightness, then a background brightness adjustment command is triggered.

[0081] When the electronic device is a VR device, the screen is only used to display images and cannot support user touch operations. Therefore, to meet the user's input needs, the VR device can also capture the user's gestures through a camera and recognize the captured gestures to determine whether the user's gesture is a backlight brightness adjustment action. When it is determined that the user's gesture is a backlight brightness adjustment action, a background brightness adjustment command is automatically triggered.

[0082] When recognizing gestures captured by the camera, the gesture image is input into a gesture detection model to detect the gesture region. This gesture region is then input into a gesture recognition model to determine whether the user's gesture is a backlight brightness adjustment action. It should be noted that the process of processing the gesture image using the gesture detection and recognition models is a conventional technique and will not be elaborated upon here.

[0083] To improve the accuracy of gesture recognition, this embodiment preprocesses the captured gesture image before recognizing it. Then, the recognition operation is performed on the preprocessed gesture image. The gesture image preprocessing may include format conversion, image enhancement, and image resizing.

[0084] After receiving a backlight brightness adjustment command from the user, the electronic device can obtain the current brightness value of the system brightness adjustment control based on the command. The system brightness adjustment control refers to the control for adjusting the backlight brightness of the LCD screen, which supports various operations such as sliding or clicking. In this embodiment, the system brightness adjustment control can be a brightness slider.

[0085] Specifically, the current brightness value of the system brightness adjustment control can be obtained as follows: determine the current position of the slider on the system brightness adjustment control; obtain the current brightness value of the system brightness adjustment control based on the current position of the slider; wherein the system brightness adjustment control is divided into multiple positions, and each position corresponds to a brightness value.

[0086] For example, when the brightness value range of the system brightness adjustment control is [0, 255], the system brightness adjustment control can be divided into 256 positions according to the number of brightness values ​​in the brightness range, or it can be divided into thousands, tens of thousands, or even more positions. The specific settings are adapted according to the brightness adjustment precision, and no specific restrictions are imposed here. Then, based on the correspondence between each brightness value and position, a mapping relationship between position and brightness value is established.

[0087] Taking the system brightness adjustment controls divided into 256 positions as an example, the details are shown in Table 1 below:

[0088] Table 1

[0089] Location Brightness value of the system brightness adjustment control Position 1 0 nits Position 2 1 nits … … Position 256 255 nits

[0090] Furthermore, when obtaining the current brightness value of the system brightness adjustment control, the mapping relationship between the above position and the brightness value can be queried based on the position of the slider of the system brightness adjustment control to determine the current brightness value of the system brightness adjustment control.

[0091] For example, if the current position of the slider on the system brightness adjustment control is the 57th position, then by consulting the mapping relationship between the corresponding position and the brightness value in Table 1 above, the current brightness value of the system brightness adjustment control can be determined to be 56 nits.

[0092] S102, based on the current brightness value, determine the duty cycle of the pulse width modulation signal driving the backlight of the liquid crystal display screen, and use the pulse width modulation signal as the first pulse width modulation signal.

[0093] The duty cycle of a pulse width modulation (PWM) signal refers to the ratio of high-level time to low-level time within one switching operation of the screen backlight. Specifically, the longer the high-level time within one switching operation, the larger the duty cycle of the PWM signal, and vice versa. The duty cycle of a PWM signal can be expressed as a percentage; for example, if the entire switching operation of the screen backlight is high-level, then the duty cycle of the PWM signal is 100%.

[0094] For example, after obtaining the current brightness value of the system brightness adjustment control, this embodiment of the application can determine the duty cycle of the pulse width modulation signal driving the backlight of the liquid crystal display screen based on the current brightness value. Specifically, this can be achieved in the following ways:

[0095] The first implementation method

[0096] By using the current brightness value, the mapping relationship between the preset system brightness adjustment control brightness value and the pulse width modulation signal duty cycle is queried to determine the duty cycle of the pulse width modulation signal corresponding to the current brightness value. The queried pulse width modulation signal duty cycle is then determined as the duty cycle of the pulse width modulation signal driving the LCD backlight.

[0097] For example, if the current brightness value is 120 nits, then based on the mapping relationship between the preset brightness value of the system brightness adjustment control and the duty cycle of the pulse width modulation signal, the duty cycle of the pulse width modulation signal corresponding to the current brightness value of 120 nits is determined to be 47.27%. Therefore, the duty cycle of the pulse width modulation signal driving the LCD backlight is determined to be 47.27%.

[0098] The second implementation method

[0099] The duty cycle of the pulse width modulation signal driving the LCD backlight is calculated using the current brightness value.

[0100] Specifically, when calculating the duty cycle of a pulse width modulation (PWM) signal, it can be calculated based on the current brightness value according to a preset method. The preset method can be any algorithm or rule capable of calculating the duty cycle of the PWM signal based on the brightness value; no specific restrictions are imposed here.

[0101] For example, when the current brightness value is 150 nits, the electronic device can calculate the duty cycle of the pulse width modulation signal corresponding to 150 nits as 58.59% according to a preset method. Therefore, the duty cycle of the pulse width modulation signal driving the LCD backlight is determined to be 58.59%.

[0102] It should be noted that the above two implementation methods are merely illustrative examples of the embodiments of this application and are not intended to limit the scope of this application.

[0103] Therefore, the pulse width modulation signal determined by the above two methods is used as the first pulse width modulation signal.

[0104] S103, based on the first pulse width modulation signal and the second pulse width modulation signal output by the liquid crystal display screen, control the working state of the switching component connected to the backlight of the liquid crystal display screen to adjust the backlight brightness of the liquid crystal display screen.

[0105] The frequency of the first pulse width modulation signal is greater than the frequency of the second pulse width modulation signal.

[0106] In this embodiment, the second pulse width modulation signal is generated according to the image refresh frequency. For example, if the image refresh frequency is 72 Hz, 90 Hz, 120 Hz, or other, the frequency of the second pulse width modulation signal is correspondingly 72 Hz, 90 Hz, 120 Hz, or other.

[0107] Furthermore, the second pulse width modulation signal is used to control the backlight of the LCD screen to achieve the black insertion function of the LCD screen.

[0108] In specific implementation, it is determined whether both the first pulse width modulation signal and the second pulse width modulation signal are at a high level. When it is determined that both the first pulse width modulation signal and the second pulse width modulation signal are at a high level, the switching component is turned on; otherwise, the switching component is turned off. See [link to details]. Figure 1 As shown.

[0109] It is understood that this application controls the switching component to conduct according to the first pulse width modulation signal and the second pulse width modulation signal, and connects the first resistor to the backlight brightness adjustment circuit to adjust the size of the current limiting resistor in the backlight brightness adjustment circuit, thereby adjusting the size of the screen backlight current, so as to achieve stepless adjustment of the backlight brightness.

[0110] The backlight brightness adjustment circuit control method provided in this application obtains the current brightness value corresponding to the backlight brightness adjustment command, determines the duty cycle of the pulse width modulation signal driving the LCD backlight based on the current brightness value, uses this pulse width modulation signal as the first pulse width modulation signal, and controls the working state of the switching component connected to the LCD backlight according to the first pulse width modulation signal and the second pulse width modulation signal output by the LCD, thereby adjusting the backlight brightness of the LCD. This achieves stepless adjustment of the backlight brightness, thereby improving user satisfaction with backlight brightness adjustment and enhancing the user experience.

[0111] As an optional implementation of this application, considering that when determining the duty cycle of the pulse width modulation signal driving the LCD backlight based on the current brightness value, the duty cycle of the pulse width modulation signal driving the LCD backlight can be determined by querying the mapping relationship between the brightness value of the preset system brightness adjustment control and the duty cycle of the pulse width modulation signal based on the current brightness value. Then, in conjunction with... Figure 6 The process of determining the duty cycle of the pulse width modulation signal that drives the backlight of the liquid crystal display screen will be explained in detail.

[0112] like Figure 6 As shown, the backlight brightness adjustment circuit control method includes the following steps:

[0113] S201, based on the received backlight brightness adjustment command, obtain the current brightness value of the system brightness adjustment control.

[0114] S202, based on the mapping relationship between the brightness value of the system brightness adjustment control and the duty cycle of the pulse width modulation signal, and the current brightness value, determine the duty cycle of the pulse width modulation signal driving the backlight of the liquid crystal display screen, and use the pulse width modulation signal as the first pulse width modulation signal.

[0115] In this embodiment, the mapping relationship between the brightness value of the system brightness adjustment control and the duty cycle of the pulse width modulation signal can be calculated based on each brightness value within the brightness value range of the system brightness adjustment control, and the corresponding duty cycle of the pulse width modulation signal is calculated for each brightness value. Then, based on the duty cycle of the pulse width modulation signal corresponding to each brightness value, a mapping relationship between the brightness value and the duty cycle of the pulse width modulation signal is established.

[0116] Specifically, for each brightness value within the brightness range of the system brightness adjustment control, the duty cycle of the pulse width modulation signal corresponding to each brightness value is calculated. This involves calculating the distance between each brightness value and the minimum brightness value of the system brightness adjustment control, as well as the distance between the minimum and maximum brightness values ​​of the system brightness adjustment control. Then, the ratio of this ratio to the distance between the minimum and maximum brightness values ​​of the system brightness adjustment control is calculated, and this ratio is used to determine the duty cycle of the pulse width modulation signal corresponding to each brightness value. Of course, this application can also implement the calculation of the duty cycle of the pulse width modulation signal corresponding to each brightness value in other ways besides the above method, and no specific limitations are imposed here.

[0117] Furthermore, after establishing the mapping relationship between the brightness value of the system brightness adjustment control and the duty cycle of the pulse width modulation signal, this mapping relationship can be stored. Based on the stored mapping relationship, the foundation can be laid for determining the duty cycle of the pulse width modulation signal driving the backlight of the liquid crystal display.

[0118] Furthermore, after obtaining the current brightness value of the system brightness adjustment control based on the backlight brightness adjustment command sent by the user, the system can then search for the pulse width modulation signal duty cycle corresponding to the current brightness value in the stored mapping relationship between the brightness values ​​of the system brightness adjustment control and the duty cycles of the pulse width modulation signal. The found pulse width modulation signal is then used as the first pulse width modulation signal.

[0119] S203, based on the first pulse width modulation signal and the second pulse width modulation signal output by the liquid crystal display screen, control the working state of the switching component connected to the backlight of the liquid crystal display screen to adjust the backlight brightness of the liquid crystal display screen.

[0120] The frequency of the first pulse width modulation signal is greater than the frequency of the second pulse width modulation signal.

[0121] The backlight brightness adjustment circuit control method provided in this application obtains the current brightness value corresponding to the backlight brightness adjustment command, determines the duty cycle of the pulse width modulation signal driving the LCD backlight based on the current brightness value, uses this pulse width modulation signal as the first pulse width modulation signal, and controls the working state of the switching component connected to the LCD backlight based on the first pulse width modulation signal and the second pulse width modulation signal output by the LCD, thereby adjusting the backlight brightness of the LCD. This achieves stepless adjustment of the backlight brightness, thereby improving user satisfaction with backlight brightness adjustment and enhancing the user experience. Furthermore, by pre-storing the mapping relationship between the brightness value of the system brightness adjustment control and the duty cycle of the pulse width modulation signal, the current brightness value can be directly queried to determine the duty cycle of the pulse width modulation signal driving the LCD backlight, effectively improving the adjustment speed of the screen backlight brightness.

[0122] As another optional implementation of this application, considering that when determining the duty cycle of the pulse width modulation signal driving the backlight of the liquid crystal display screen based on the current brightness value, the duty cycle of the pulse width modulation signal driving the backlight of the liquid crystal display screen can also be calculated based on the current brightness value. Then, in conjunction with... Figure 7 The process of calculating the duty cycle of the pulse width modulation signal that drives the backlight of the liquid crystal display screen will be further explained.

[0123] like Figure 7As shown, the backlight brightness adjustment method includes the following steps:

[0124] S301: Based on the received backlight brightness adjustment command, obtain the current brightness value of the system brightness adjustment control.

[0125] S302, based on the current brightness value, calculate the duty cycle of the pulse width modulation signal driving the backlight of the liquid crystal display screen, and use the pulse width modulation signal as the first pulse width modulation signal.

[0126] For example, the duty cycle of the pulse width modulation signal driving the backlight of the liquid crystal display screen can be calculated based on the current brightness value in the following way: First, determine the first distance between the current brightness value and the minimum brightness value of the system brightness adjustment control, and determine the second distance between the minimum brightness value and the maximum brightness value of the system brightness adjustment control. Then, divide the first distance by the second distance to obtain the ratio, and use the ratio as the duty cycle of the pulse width modulation signal driving the backlight of the liquid crystal display screen.

[0127] In practice, it can be achieved using the following formula:

[0128]

[0129] Among them, Z i a represents the duty cycle of the i-th pulse width modulation signal corresponding to the i-th brightness value. i Let a represent the i-th brightness value. n Let i represent the nth brightness value, where i ≤ n and 0 ≤ n ≤ 255.

[0130] For example, if the current brightness value is 250 nits, then the duty cycle of the pulse width modulation signal driving the LCD backlight can be calculated using the above formula:

[0131] Then, the pulse width modulation signal determined in the above manner is used as the first pulse width modulation signal.

[0132] S303, based on the first pulse width modulation signal and the second pulse width modulation signal output by the liquid crystal display screen, control the working state of the switching component connected to the backlight of the liquid crystal display screen to adjust the backlight brightness of the liquid crystal display screen.

[0133] The frequencies of the first pulse width modulation signal and the second pulse width modulation signal are different.

[0134] The backlight brightness adjustment circuit control method provided in this application obtains the current brightness value corresponding to the backlight brightness adjustment command, determines the duty cycle of the pulse width modulation signal driving the LCD backlight based on the current brightness value, uses this pulse width modulation signal as the first pulse width modulation signal, and controls the working state of the switching component connected to the LCD backlight according to the first pulse width modulation signal and the second pulse width modulation signal output by the LCD, thereby adjusting the backlight brightness of the LCD. This achieves stepless adjustment of the backlight brightness, thereby improving user satisfaction with backlight brightness adjustment and enhancing the user experience.

[0135] Figure 8 This is a schematic block diagram of an electronic device provided in an embodiment of this application.

[0136] like Figure 8 As shown, the electronic device 400 includes a backlight brightness adjustment circuit 100 according to any of the foregoing embodiments.

[0137] In this embodiment, the electronic device is preferably a virtual reality device, i.e., a VR (Virtual Reality) device, such as a VR all-in-one machine, a VR headset, or VR glasses.

[0138] It should be understood that this electronic device embodiment corresponds to the aforementioned backlight brightness adjustment circuit embodiment, and similar descriptions can be found in the backlight brightness adjustment circuit embodiment. To avoid repetition, further details are omitted here.

[0139] The electronic device provided in this application embodiment, by setting a backlight brightness adjustment circuit, includes an AND gate circuit, a first switch component, a second switch component, a first resistor, a second resistor, a voltage comparator, and a pull-up resistor. Based on the pulse width modulation signal output by the controller and the liquid crystal display, the first resistor is controlled to be connected to the backlight brightness adjustment circuit. By adjusting the size of the current-limiting resistor in the backlight brightness adjustment circuit, the current of the screen backlight is adjusted, thereby achieving stepless adjustment of the backlight brightness, thereby improving user satisfaction with the backlight brightness adjustment and enhancing the user experience.

[0140] Those skilled in the art will recognize that the modules and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0141] In the several embodiments provided in this application, it should be understood that the disclosed systems, apparatuses, and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of modules is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple modules or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or modules may be electrical, mechanical, or other forms.

[0142] The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. For example, the functional modules in the various embodiments of this application may be integrated into one processing module, or each module may exist physically separately, or two or more modules may be integrated into one module.

[0143] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A backlight brightness adjustment circuit, characterized by, include: AND gate circuit, first switching assembly, second switching assembly, first resistor, second resistor, voltage comparator, LED array and pull-up resistor; The control terminal of the first switch assembly is connected to the output terminal of the AND gate circuit, one end of the first switch assembly is connected to one end of the first resistor, and the other end of the first switch assembly is grounded. The other end of the first resistor is connected to the first input terminal of the voltage comparator, one end of the second switching assembly, and one end of the second resistor, while the other end of the second resistor is grounded. The second input terminal of the voltage comparator is connected to the power supply, and the output terminal of the voltage comparator is connected to the control terminal of the second switching assembly. The other end of the second switching assembly is connected to the LED array and one end of the pull-up resistor, and the other end of the pull-up resistor is connected to the power supply. The first input terminal of the AND gate circuit is connected to the controller, and the second input terminal of the AND gate circuit is connected to the liquid crystal display screen. It is used to control the operating state of the first switching component based on the first pulse width modulation signal output by the controller and the second pulse width modulation signal output by the liquid crystal display screen. When the output terminal of the AND gate circuit outputs a high level, the first switching component is turned on, connecting the first resistor and the second resistor in parallel, thus reducing the total current-limiting resistance. By controlling the duration of the high-level output of the AND gate circuit, the duration of the first resistor's connection is controlled, thereby adjusting the backlight current by changing the total current-limiting resistance, achieving stepless adjustment of the backlight brightness. The first pulse width modulation signal is generated based on the current brightness value of the backlight of the liquid crystal display screen, and the frequency of the first pulse width modulation signal is greater than the frequency of the second pulse width modulation signal.

2. The backlight brightness adjustment circuit of claim 1, wherein, Also includes: The third switching assembly, the third resistor, and the fourth resistor; One end of the third switch assembly is connected to one end of the third resistor, the other end of the third switch assembly is connected to the power supply, and the control terminal of the third switch assembly is connected to the liquid crystal display screen. The other end of the third resistor is connected to the second input terminal of the voltage comparator and one end of the fourth resistor; The other end of the fourth resistor is grounded.

3. The backlight brightness adjustment circuit according to claim 1 or 2, characterized in that, Also includes: A current-limiting resistor is connected in series between the voltage comparator and the second switching assembly.

4. The backlight brightness adjustment circuit according to claim 1 or 2, characterized in that, Also includes: diode; The anode of the diode is connected to the other end of the pull-up resistor; The cathode of the diode is connected to the other end of the LED array and the second switching assembly.

5. The backlight brightness adjustment circuit according to claim 1 or 2, characterized in that, The first switching component is a metal-oxide-semiconductor field-effect transistor.

6. The backlight brightness adjustment circuit according to claim 1, characterized in that, The second switching component is a transistor.

7. The backlight brightness adjustment circuit according to claim 1, characterized in that, The LED array includes at least one LED light.

8. A backlight brightness adjustment circuit control method, characterized in that, The backlight brightness adjustment circuit includes: an AND gate circuit, a first switching component, a first resistor, and a second resistor; the method includes: Based on the received backlight brightness adjustment command, obtain the current brightness value of the system brightness adjustment control; Based on the current brightness value, determine the duty cycle of the pulse width modulation signal that drives the backlight of the liquid crystal display screen, and use the pulse width modulation signal as the first pulse width modulation signal; Based on the first pulse width modulation signal and the second pulse width modulation signal output by the liquid crystal display screen, the working state of the switching component connected to the backlight of the liquid crystal display screen is controlled to adjust the backlight brightness of the liquid crystal display screen. When the output terminal of the AND gate circuit outputs a high level, the first switching component is turned on to connect the first resistor and the second resistor in parallel, thereby reducing the total current limiting resistance. By controlling the duration of the high level output by the AND gate circuit, the duration of the first resistor connection is controlled, thereby adjusting the current of the screen backlight by changing the total current limiting resistance, thus achieving stepless adjustment of the backlight brightness. The frequency of the first pulse width modulation signal is greater than the frequency of the second pulse width modulation signal.

9. The method according to claim 8, characterized in that, Controlling the operating state of a switching assembly connected to the backlight of the liquid crystal display screen to adjust the backlight brightness of the liquid crystal display screen includes: When the first pulse width modulation signal and the second pulse width modulation signal are at a high level, the switching component is controlled to be turned on; otherwise, the switching component is controlled to be turned off.

10. The method according to claim 8, characterized in that, Determining the duty cycle of the pulse width modulation signal driving the LCD backlight includes: Based on the mapping relationship between the brightness value of the system brightness adjustment control and the duty cycle of the pulse width modulation signal, and the current brightness value, the duty cycle of the pulse width modulation signal driving the backlight of the liquid crystal display screen is determined. or, Based on the current brightness value, calculate the duty cycle of the pulse width modulation signal driving the backlight of the liquid crystal display screen.

11. The method according to claim 10, characterized in that, Based on the current brightness value, calculate the duty cycle of the pulse width modulation signal driving the backlight of the liquid crystal display screen, including: Determine a first distance between the current brightness value and the minimum brightness value of the system brightness adjustment control, and a second distance between the minimum brightness value and the maximum brightness value of the system brightness adjustment control; Calculate the ratio of the first distance to the second distance, and use the ratio as the duty cycle of the pulse width modulation signal driving the backlight of the liquid crystal display screen.

12. The method according to claim 8, characterized in that, Get the current brightness value of the system brightness adjustment control, including: Determine the current position of the slider on the system brightness adjustment control; Based on the current position of the slider, obtain the current brightness value of the system brightness adjustment control; The system brightness adjustment control is divided into multiple positions, and each position corresponds to a brightness value.

13. An electronic device, characterized in that, include: The backlight brightness adjustment circuit as described in any one of claims 1-7.

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