Screen brightness control method and electronic device

Abstract

This application discloses a screen brightness control method and electronic device. When the screen's dimming mode is PWM dimming, once the user's finger is detected placing on the fingerprint recognition area of ​​the screen for fingerprint unlocking, the electronic device can control the screen to switch from PWM dimming to DC dimming. After this switch, the screen pixels undergo two grayscale reductions to maintain stable screen brightness. The first grayscale reduction occurs within the first frame after switching to DC dimming, and the second grayscale reduction occurs after the first frame. The degree of the first grayscale reduction is greater than that of the second grayscale reduction to improve the screen flickering problem in the first frame.

Description

Technical Field

[0001] This application relates to the field of terminal technology, and in particular to screen brightness control methods and electronic devices. Background Technology

[0002] To protect user privacy, electronic devices such as mobile phones, tablets, and personal computers offer screen lock functions. Unlocking methods can include: numeric password unlocking, pattern password unlocking, facial recognition unlocking, and fingerprint unlocking. Among these, fingerprint unlocking is widely used due to its ease of use and reliability. Optical fingerprint recognition technology, used in organic light-emitting diode (OLED) screens, is one way to achieve fingerprint unlocking. When a user places their finger on the fingerprint recognition area on the screen to unlock, the electronic device controls the under-screen fingerprint sensor, such as a complementary metal-oxide-semiconductor (CMOS) / charge-coupled device (CCD) sensor, to perform optical imaging and collect the fingerprint. Furthermore, fingerprint collection requires the OLED screen to illuminate the finger; the light passes through the skin and reflects onto the fingerprint sensor. However, fingerprint collection poses a challenge to the brightness control of OLED screens, potentially leading to unstable screen brightness. Summary of the Invention

[0003] This application provides a screen brightness control method and electronic device. When the screen's dimming mode is PWM dimming, once the device detects a user's finger placed on the fingerprint recognition area of ​​the screen for fingerprint unlocking, it can control the screen to switch from PWM dimming to DC dimming. After this switch, the screen pixels undergo two grayscale reductions to maintain stable screen brightness. The first grayscale reduction occurs within the first frame after switching to DC dimming, and the second grayscale reduction occurs after the first frame. The degree of the first grayscale reduction is greater than that of the second grayscale reduction to improve the screen flickering issue in the first frame.

[0004] In a first aspect, embodiments of this application provide a screen brightness control method applied to an electronic device, the electronic device including a screen, the method comprising: the electronic device controlling the screen to operate in pulse width modulation (PWM) dimming mode and displaying a lock screen interface; the electronic device detecting a user touching a fingerprint recognition area within the screen; the electronic device controlling the screen to switch from PWM dimming mode to DC dimming mode, acquiring a fingerprint, and in the first frame after the switch, using a first ratio to reduce the grayscale of pixels outside the fingerprint recognition area on the screen; after the first frame, the electronic device using a second ratio to reduce the grayscale of pixels outside the fingerprint recognition area on the screen; if the acquired fingerprint matches the registered fingerprint, the electronic device unlocks the screen; wherein the first ratio is lower than the second ratio.

[0005] The first ratio can be ratio a, and the second ratio can be ratio b.

[0006] By implementing the method provided in the first aspect, electronic devices can control the screen brightness to remain constant before and after fingerprint unlocking, and can solve the problem of sudden changes in screen brightness in the first frame when the screen switches from PWM dimming mode to DC dimming mode when unlocking at any brightness.

[0007] In conjunction with the first aspect, in some embodiments, after detecting that a user has touched a fingerprint recognition area within the screen, the method further includes: the electronic device displaying a fingerprint spot image of a first grayscale in the fingerprint recognition area, the first grayscale being higher than the average grayscale of the lock screen interface.

[0008] The first gray level can be a preset gray level that is higher than the average gray level of the lock screen interface.

[0009] In this way, the electronic device can display a fingerprint spot image of the first gray level (such as a gray level value of 255) in the fingerprint recognition area. This fingerprint spot image can be superimposed on the image displayed on the lock screen interface, thereby significantly improving the brightness of the fingerprint recognition area, illuminating the finger, and making it easier for the electronic device to collect a clear fingerprint.

[0010] In conjunction with the first aspect, in some embodiments, the second ratio is determined based on the first screen brightness and the second screen brightness; wherein the first screen brightness is the minimum screen brightness at which the screen enters DC dimming mode; the second screen brightness is the screen brightness when the electronic device controls the screen to work in PWM dimming mode; the greater the first screen brightness, the smaller the second ratio; the greater the second screen brightness, the greater the second ratio.

[0011] In conjunction with the first aspect, in some embodiments, the relationship between the second ratio and the first screen brightness and the second screen brightness satisfies the following gamma formula: Second ratio = (Second screen brightness / First screen brightness) 1 / x , where x represents the gamma value.

[0012] In conjunction with the first aspect, in some embodiments, the first ratio is determined based on a second ratio and a second screen brightness; wherein the second screen brightness is the screen brightness when the electronic device controls the screen to operate in PWM dimming mode; the greater the second screen brightness, the greater the first ratio.

[0013] In conjunction with the first aspect, in some embodiments, the electronic device controls the screen to operate in pulse width modulation (PWM) dimming mode, specifically including: the electronic device controls the screen brightness to be below a first screen brightness, where the first screen brightness is the minimum screen brightness at which the screen enters DC dimming mode.

[0014] In conjunction with the first aspect, in some embodiments, the electronic device controls the screen to switch from PWM dimming mode to DC dimming mode, specifically including: the screen brightness of the electronic device controls the screen to be above a first screen brightness, where the first screen brightness is the minimum screen brightness at which the screen enters DC dimming mode.

[0015] In conjunction with the first aspect, in some embodiments, before using the first ratio to reduce the grayscale of pixels outside the fingerprint recognition area on the screen, the method further includes: the electronic device detecting that the electronic device is in a low-light environment.

[0016] In conjunction with the first aspect, in some embodiments, the method further includes: the electronic device detecting that the electronic device has entered a first power-saving mode; determining the ratio corresponding to the first power-saving mode in a first table as a first ratio; wherein the first table is used to record the ratio corresponding to one or more power-saving modes; the ratio corresponding to each power-saving mode is greater than the ratio when the electronic device does not enter a power-saving mode.

[0017] The first power saving mode can be, for example, a light power saving mode or a deep power saving mode, and the first table can be, for example, Table 3.

[0018] In this way, electronic devices can flexibly identify power-saving scenarios based on the overall solution, and adapt different first ratios according to different screen brightness peaks under different power-saving scenarios.

[0019] In conjunction with the first aspect, in some embodiments, the electronic device further includes a fingerprint sensor and a display driver integrated circuit (DDIC); the DDIC is connected to the screen; the electronic device runs a first software system, the first software system including a touch driver, a fingerprint driver, a display driver, and a fingerprint hardware abstraction layer; the screen is used to detect a first operation by a user touching a fingerprint recognition area within the screen, and transmits an event corresponding to the first operation to the touch driver; the touch driver is used to transmit the event corresponding to the first operation to the fingerprint driver; the fingerprint driver is used to control the fingerprint sensor to collect a fingerprint after receiving the event corresponding to the first operation; the fingerprint driver is also used to transmit the event corresponding to the first operation to the fingerprint hardware abstraction layer; the fingerprint hardware abstraction layer is used to notify the display driver of the first operation; the display driver is used to control the DDIC to switch the screen from PWM dimming mode to DC dimming mode after learning of the first operation, and in the first frame after the switch, use a first ratio to reduce the grayscale of pixels outside the fingerprint recognition area in the screen, and in the subsequent frames, use a second ratio to reduce the grayscale of pixels outside the fingerprint recognition area in the screen; the first ratio is less than the second ratio.

[0020] The first software system can be as follows: Figure 11 The software system shown (excluding the hardware layer) allows the first operation to be the user touching the fingerprint recognition area on the screen.

[0021] In conjunction with the first aspect, in some embodiments, the display driver is further configured to, upon knowing of the first operation, control the DDIC to display a fingerprint spot image of a first grayscale in the fingerprint recognition area, wherein the first grayscale is higher than the average grayscale of the lock screen interface.

[0022] In conjunction with the first aspect, in some embodiments, the display driver is also used to control the DDIC to increase the screen refresh rate after knowing the first operation.

[0023] In conjunction with the first aspect, in some embodiments, after detecting that a user has touched a fingerprint recognition area within the screen, the method further includes: the electronic device increasing the screen refresh rate.

[0024] In this way, after detecting that the user has touched the fingerprint recognition area on the screen, the electronic device can respond to the user's touch operation on the screen in a timely manner with a higher screen refresh rate, thereby improving the user experience.

[0025] In conjunction with the first aspect, in some embodiments, the first frame includes one or more frames.

[0026] In conjunction with the first aspect, in some embodiments, the screen is an organic light-emitting diode (OLED) screen.

[0027] Secondly, embodiments of this application provide an electronic device, which includes a display screen, a memory, and a processor coupled to the memory; the display screen is used to display an interface, the memory stores a computer program, and when the processor executes the computer program, the electronic device implements the method described in any one of the first aspects.

[0028] Thirdly, embodiments of this application provide a computer-readable storage medium storing a computer program or computer instructions, which are executed by a processor to implement the method described in any of the first aspects above.

[0029] Fourthly, embodiments of this application provide a computer program product, which, when executed by a processor, implements the method described in any of the first aspects above.

[0030] Fifthly, embodiments of this application provide a chip including a processor and a memory, wherein the memory is used to store computer programs or computer instructions, and the processor is used to execute the computer programs or computer instructions stored in the memory, causing the chip to perform the method described in any of the first aspects above.

[0031] The solutions provided in the second to fifth aspects above are used to implement or cooperate with the methods provided in the first aspect above, and therefore can achieve the same or corresponding beneficial effects as the methods in the first aspect, which will not be elaborated here. Attached Figure Description

[0032] Figure 1 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application;

[0033] Figure 2 This is a schematic diagram illustrating a scenario where screen brightness suddenly changes during fingerprint unlocking, as provided in an embodiment of this application.

[0034] Figure 3 This is a schematic diagram of a pixel circuit in an OLED screen provided in an embodiment of this application;

[0035] Figure 4 This is a schematic diagram illustrating the screen brightness change caused by fingerprint unlocking, as provided in an embodiment of this application.

[0036] Figure 5 This is a schematic diagram illustrating a scenario where screen brightness remains stable during fingerprint unlocking, as provided in an embodiment of this application.

[0037] Figure 6 This is a flowchart of a screen brightness control method provided in an embodiment of this application;

[0038] Figure 7This is a schematic diagram of gamma curves corresponding to different display brightness values ​​provided in an embodiment of this application;

[0039] Figure 8 This is a schematic diagram illustrating the correspondence between DBV and nit provided in an embodiment of this application;

[0040] Figure 9 This is a schematic diagram illustrating how ratio a is obtained from the screen brightness and ratio b at a first moment, according to an embodiment of this application.

[0041] Figure 10 This is a schematic diagram of signal changes in an application screen brightness control method provided in an embodiment of this application;

[0042] Figure 11 This is a software structure block diagram of an electronic device provided in an embodiment of this application. Detailed Implementation

[0043] The terminology used in the following embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be a limitation of this application.

[0044] This application provides an electronic device for performing a screen brightness control method.

[0045] Figure 1 An electronic device provided in an embodiment of this application is shown.

[0046] In this application embodiment, the device type of the electronic device can be any of the following: mobile phone, tablet computer, handheld computer, desktop computer, laptop computer, ultra-mobile personal computer (UMPC), netbook, cellular phone, personal digital assistant (PDA), as well as smart home devices such as smart screens and smart speakers, wearable devices such as smart bracelets, smartwatches, and smart glasses, extended reality (XR) devices such as augmented reality (AR), virtual reality (VR), and mixed reality (MR), in-vehicle devices, or smart city devices.

[0047] like Figure 1As shown, the electronic device may include: a processor 110, a memory 120, a display screen 130, a display driver integrated circuit (DDIC) 140, an antenna 1, an antenna 2, a mobile communication module 150, a wireless communication module 160, an audio module 170, a speaker 170A, a receiver 170B, a microphone 170C, a headphone jack 170D, a sensor module 180, buttons 190, a motor 191, an indicator 192, a camera 193, and a subscriber identification module (SIM) card interface 194, etc. The sensor module 180 may include a fingerprint sensor 180A, a touch sensor 180B, and an ambient light sensor 180C, etc. The various components in the electronic device can be connected via a bus.

[0048] Figure 1 The illustrated structure does not constitute a specific limitation on the electronic device. An electronic device may include more or fewer components than illustrated, or combine or separate certain components, or have different component arrangements. The illustrated components may be implemented in hardware, software, or a combination of both.

[0049] The processor 110 can be one or more, and they can be integrated into an integrated circuit of a system-on-a-chip (SOC). An SOC is a system-on-a-chip. The processor 110 may include a central processing unit (CPU) and a graphics processing unit (GPU). The CPU can be an application processor (AP). The CPU and GPU can be used to render and composite the image to be displayed on the screen 130. The processor 110 may also include a neural network processing unit (NPU), a modem processor, etc.

[0050] The processor 110 may include one or more interfaces, such as an inter-integrated circuit (I2C) interface, an inter-integrated circuit sound (I2S) interface, a pulse code modulation (PCM) interface, a universal asynchronous receiver / transmitter (UART) interface, a mobile industry processor interface (MIPI), a general purpose input / output (GPIO) interface, a subscriber identity module (SIM) interface, and / or a universal serial bus (USB) interface.

[0051] The processor 110 may have a cache memory, which can be used to store instructions or data that the processor 110 has just used or that are used repeatedly. If the processor 110 needs to use the instruction or data again, it can directly retrieve it from the cache memory, which can reduce the waiting time of the processor 110 and improve the program running efficiency.

[0052] The memory 120 may include a program storage area and a user data storage area. The program storage area may store the operating system and one or more applications (such as games), while the data storage area may store data created by the user during the use of the electronic device (such as photos and contacts). The memory 130 may be a high-speed random access memory or a non-volatile memory, such as a hard disk, flash memory, or universal flash storage (UFS). The memory 120 may also be an external memory card, such as a Micro SD card.

[0053] The memory 120 may also store code instructions for the display method provided in the embodiments of this application. When the processor 110 reads the code instructions from the memory 120 and runs the code instructions, the electronic device can execute the display method.

[0054] The memory 120 can also be integrated with the processor 110 into the integrated circuit of the SOC.

[0055] The wireless communication function of electronic devices can be realized through antenna 1, antenna 2, mobile communication module 150, wireless communication module 160, modem processor and baseband processor, etc.

[0056] Antenna 1 and antenna 2 are used to transmit and receive electromagnetic wave signals. Each antenna in the electronic device can be used to cover one or more communication frequency bands. Different antennas can also be reused to improve antenna utilization. For example, antenna 1 can be reused as a diversity antenna for a wireless local area network. In some other embodiments, the antennas can be used in conjunction with a tuning switch.

[0057] The mobile communication module 150 can provide solutions for wireless communication applications including 2G / 3G / 4G / 5G in electronic devices. The mobile communication module 150 may include at least one filter, switch, power amplifier, low noise amplifier (LNA), etc. The mobile communication module 150 can receive electromagnetic waves via antenna 1, and perform filtering, amplification, and other processing on the received electromagnetic waves before transmitting them to a modem processor for demodulation. The mobile communication module 150 can also amplify the signal modulated by the modem processor and convert it into electromagnetic waves for radiation via antenna 1. In some embodiments, at least some functional modules of the mobile communication module 150 may be housed in processor 110. In some embodiments, at least some functional modules of the mobile communication module 150 and at least some modules of the processor 110 may be housed in the same device.

[0058] The modem processor may include a modulator and a demodulator. The modulator modulates the low-frequency baseband signal to be transmitted into a mid-to-high frequency signal. The demodulator demodulates the received electromagnetic wave signal into a low-frequency baseband signal. The demodulator then transmits the demodulated low-frequency baseband signal to the baseband processor for processing. After processing by the baseband processor, the low-frequency baseband signal is transmitted to the application processor. The application processor outputs sound signals through an audio device (not limited to speaker 170A, receiver 170B, etc.) or displays images or videos through the display screen 130. In some embodiments, the modem processor may be a separate device. In other embodiments, the modem processor may be independent of the processor 110 and may be housed in the same device as the mobile communication module 150 or other functional modules.

[0059] The wireless communication module 160 can provide solutions for wireless communication applications in electronic devices, including wireless local area networks (WLANs) (such as wireless fidelity (Wi-Fi) networks), Bluetooth (BT), global navigation satellite system (GNSS), frequency modulation (FM), near field communication (NFC), and infrared (IR) technologies. The wireless communication module 160 can be one or more devices integrating at least one communication processing module. The wireless communication module 160 receives electromagnetic waves via antenna 2, performs frequency modulation and filtering of the electromagnetic wave signals, and sends the processed signal to processor 110. The wireless communication module 160 can also receive signals to be transmitted from processor 110, perform frequency modulation and amplification, and convert them into electromagnetic waves for radiation via antenna 2.

[0060] In some embodiments, antenna 1 of the electronic device is coupled to mobile communication module 150, and antenna 2 is coupled to wireless communication module 160, enabling the electronic device to communicate with networks and other devices via wireless communication technology. The wireless communication technology may include Global System for Mobile Communications (GSM), General Packet Radio Service (GPRS), Code Division Multiple Access (CDMA), Wideband Code Division Multiple Access (WCDMA), Time-Division Code Division Multiple Access (TD-SCDMA), Long Term Evolution (LTE), BT, GNSS, WLAN, NFC, FM, and / or IR technologies. The GNSS may include Global Positioning System (GPS), Global Navigation Satellite System (GLONASS), BeiDou Navigation Satellite System (BDS), Quasi-Zenith Satellite System (QZSS), and / or Satellite Based Augmentation Systems (SBAS).

[0061] Electronic devices can achieve shooting functions through ISP, camera 193, video codec, GPU, display 130 and application processor.

[0062] The ISP (Image Signal Processor) is used to process data fed back from the camera 193. For example, when taking a picture, the shutter is opened, and light is transmitted through the lens to the camera's photosensitive element. The light signal is converted into an electrical signal, and the camera's photosensitive element transmits the electrical signal to the ISP for processing, transforming it into an image visible to the naked eye. The ISP can also perform algorithmic optimization of image noise, brightness, and skin tone. The ISP can also optimize parameters such as exposure and color temperature of the shooting scene. In some embodiments, the ISP can be set in the camera 193.

[0063] Camera 193 is used to capture still images or videos. An object is projected onto a photosensitive element by generating an optical image through the lens. The photosensitive element can be a charge-coupled device (CCD) or a complementary metal-oxide-semiconductor (CMOS) phototransistor. The photosensitive element converts the light signal into an electrical signal, which is then passed to an ISP for conversion into a digital image signal. The ISP outputs the digital image signal to a DSP for processing. The DSP converts the digital image signal into image signals in standard RGB, YUV, or other formats. In some embodiments, the electronic device may include one or N cameras 193, where N is a positive integer greater than 1.

[0064] Digital signal processors (DSPs) are used to process digital signals. Besides digital image signals, they can also process other digital signals. For example, when an electronic device is selecting a frequency, a DSP can perform a Fourier transform on the frequency energy.

[0065] Video codecs are used to compress or decompress digital video. Electronic devices can support one or more video codecs. This allows the electronic device to play or record video in various encoded formats, such as Moving Picture Experts Group (MPEG) 1, MPEG2, MPEG3, MPEG4, etc.

[0066] An NPU (Neural Processing Unit) is a computational processor for neural networks (NNs). By borrowing the structure of biological neural networks, such as the transmission patterns between neurons in the human brain, it can rapidly process input information and continuously learn on its own. NPUs enable intelligent cognitive applications in electronic devices, such as image recognition, facial recognition, speech recognition, and text understanding.

[0067] Electronic devices can implement audio functions such as music playback and recording through audio modules 170, speakers 170A, receivers 170B, microphones 170C, headphone jacks 170D, and application processors.

[0068] The audio module 170 is used to convert digital audio information into analog audio signals for output, and also to convert analog audio input into digital audio signals. The audio module 170 can also be used for encoding and decoding audio signals. In some embodiments, the audio module 170 may be located in the processor 110, or some functional modules of the audio module 170 may be located in the processor 110.

[0069] Buttons 190 include a power button, volume buttons, etc. Buttons 190 can be mechanical buttons or touch buttons. The electronic device can receive button inputs and generate key signal inputs related to user settings and function control. Motor 191 can generate vibration alerts. Indicator 192 can be an indicator light, used to indicate charging status, battery level changes, messages, missed calls, notifications, etc. SIM card interface 194 is used to connect a SIM card. The SIM card can be inserted into or removed from the SIM card interface 194 to achieve contact and separation with the electronic device.

[0070] Touch sensor 180B, also known as a touch panel or touch-sensitive surface, can be disposed on display screen 130. The touch sensor 180B and display screen 130 together form a touchscreen, also called a "touchscreen." Touch sensor 180B is used to detect touch operations applied to or near it. Touch sensor 180B can transmit the detected touch operation to the application processor to determine the touch event type. In this embodiment, touch sensor 180B can be used to detect a user's touch on the fingerprint recognition area within display screen 130 and transmit the detected touch operation to fingerprint sensor 180A to determine that the event corresponding to the touch operation is a fingerprint unlocking event. Touch sensor 180B can also provide visual output related to the touch operation through display screen 130, such as displaying a fingerprint spot after a user places their finger on the fingerprint recognition area within display screen 130. In other embodiments, touch sensor 180B may also be disposed on the surface of the electronic device, in a different location than display screen 130.

[0071] An ambient light sensor 180C can be used to sense ambient light brightness. The electronic device can adaptively adjust the brightness of the display screen 130 based on the sensed ambient light brightness. In this embodiment, the ambient light sensor 180C can be used to detect whether the electronic device is in a low-light environment (i.e., whether the ambient light brightness is lower than a preset ambient light brightness). This low-light environment is relative to a strong-light environment; for example, the ambient light brightness in a low-light environment is below 50 lux. If the electronic device has its automatic screen brightness adjustment function enabled, then when the ambient light sensor 180C detects that the electronic device is in a low-light environment, the electronic device can adaptively reduce the screen brightness, thereby affecting the backlight level of the screen. If the electronic device does not have its automatic screen brightness adjustment function enabled, then the screen brightness is not affected by the ambient light brightness detected by the ambient light sensor 180C, and the user can manually adjust the screen brightness. The ambient light sensor 180C can also be used to automatically adjust the white balance when taking photos.

[0072] In this embodiment, the display screen 130 may be an OLED screen. The fingerprint sensor 180A may be disposed below the display screen 130, specifically below the fingerprint recognition area on the display screen 130 (also referred to as the screen).

[0073] Electronic devices can achieve display functions through SOC, DDIC 140, and display screen 130, etc.

[0074] The display driver integrated circuit (DDIC) 140 serves as the control core of the display screen 130, driving the display screen 130 to operate and receiving data from the SOC (processor 110), such as image data and some instructions. The DDIC 140 can send drive signals and data to the display panel of the display screen 130 in the form of electrical signals, thereby controlling the screen brightness and color, enabling image information such as letters and pictures to be displayed on the screen and completing the screen refresh.

[0075] The screen refresh rate is the number of times the display refreshes its image per second. For example, a 60Hz refresh rate means the display refreshes its image 60 times per second. After the screen is successfully unlocked, the SOC can control the DDIC 140 to increase the screen refresh rate to respond promptly to user touch operations on the screen.

[0076] Electronic devices can also achieve fingerprint unlocking functionality through SOC, DDIC 140, display 130, and fingerprint sensor 180A.

[0077] The fingerprint sensor 180A can be a CMOS / CCD sensor or even a fisheye-like camera. When a user places their finger on the fingerprint recognition area, the light emitted by the display 130 illuminates the finger, and the reflected light from the fingerprint shines through the screen onto the fingerprint sensor 180A under the screen. During fingerprint unlocking, to more clearly illuminate the finger, the DDIC 140 can control the display 130 to display a fingerprint image with a high grayscale value (e.g., a grayscale value of 255) in the fingerprint recognition area to form a fingerprint spot. This fingerprint spot helps the fingerprint sensor 180A to capture a clear fingerprint. The SOC can compare the captured fingerprint with the registered fingerprint; if the captured fingerprint matches the registered fingerprint, the unlocking is confirmed to be successful.

[0078] The brightness adjustment method of OLED screens differs from that of LCD screens. OLED screen brightness is not adjusted by the screen backlight, but rather by controlling the brightness while simultaneously controlling the color of the screen pixels. Furthermore, when the screen brightness is below a preset brightness A (e.g., 75 nits), the OLED screen uses PWM dimming mode; when the screen brightness is above this preset brightness A, the OLED screen uses DC dimming mode. Typically, screen manufacturers write this dimming logic into the driver integrated circuit (such as DDIC), which cannot be changed. This preset brightness A is the minimum screen brightness required to enter DC dimming mode.

[0079] Here, DC dimming changes screen brightness by increasing or decreasing circuit power. Changing voltage or current can alter circuit power. PWM dimming, on the other hand, doesn't rely on changing circuit power to change screen brightness; instead, it relies on the screen's alternating on and off states. That is, the screen doesn't emit light continuously but alternates between being on and off. When screen brightness decreases to a certain level, the changes in brightness of the three primary color pixels can no longer be represented as color changes, and color changes cannot be controlled. Therefore, OLED screens do not use DC dimming at low brightness levels but instead use PWM dimming. In PWM dimming, the actual current or voltage on the pixels is relatively high, color expression is unaffected, and the perceived brightness value is changed by altering the PWM duty cycle.

[0080] When the screen's on / off cycle is fast enough, such as 90Hz, the human eye cannot perceive this flicker and will perceive the screen as constantly lit. However, during fingerprint collection, the under-display fingerprint sensor can detect this flicker, resulting in an image with alternating bright and dark areas. Therefore, if the screen brightness is lower than the aforementioned preset brightness A before fingerprint collection, and the screen uses PWM dimming mode, then during fingerprint collection, the electronic device can control the screen to switch from PWM dimming mode to DC dimming mode to cooperate with the fingerprint sensor. Specifically, the electronic device can increase the screen brightness to or above the aforementioned preset brightness A to trigger the dimming logic written into the DDIC by the screen manufacturer, thereby controlling the screen to enter DC dimming mode.

[0081] However, this switch from PWM dimming to DC dimming causes instability in the screen pixel circuitry, manifesting as a sudden increase in screen brightness in the first frame after the switch. Figure 2 As shown, in low-light environments, users will experience a brief period of screen flashing when their finger touches the fingerprint recognition area.

[0082] Figure 2 An example is shown where the screen brightness suddenly changes when unlocking with a fingerprint.

[0083] like Figure 2 As shown, before the user touches the fingerprint recognition area 101 on the screen, the screen brightness is L1. After the user touches the fingerprint recognition area 101, the screen brightness first abruptly changes to L2, and then returns to L1. L2 is significantly greater than L1. Furthermore, after the user touches the fingerprint recognition area 101, the electronic device can also display a fingerprint spot 102 on the fingerprint recognition area 101. The fingerprint spot 102 is a fingerprint-like image with a specific high grayscale value (e.g., a grayscale value of 255), which significantly improves the brightness of the fingerprint recognition area 101, thereby illuminating the finger and facilitating the fingerprint sensor to capture a clear fingerprint.

[0084] Figure 3 This diagram illustrates a pixel circuit in an OLED screen. When the screen switches from PWM dimming mode to DC dimming mode, the power supply to the EM terminal of the pixel circuit changes: the number of pulses decreases, and the duty cycle increases. This power supply change affects the operating state of the pixel circuit, such as the potentials at positions N2 and N4. Furthermore, the thin-film transistors (TFTs) in the pixel circuit are field-effect transistors, exhibiting hysteresis characteristics. After switching from PWM dimming to DC dimming, they cannot immediately reach a stable state and require a period of time to recover. Therefore, in the first frame after this switch, the screen experiences a sudden brightness change, leading to screen flickering.

[0085] To address the aforementioned issues, this application provides a screen brightness control method to maintain stable screen brightness, unaffected by fingerprint unlocking.

[0086] In this method, when the screen's dimming mode is PWM dimming, once the user's finger is detected placing on the fingerprint recognition area of ​​the screen for fingerprint unlocking, the electronic device can control the screen to switch from PWM dimming to DC dimming. After this switch, the screen pixels undergo two grayscale reductions to maintain stable screen brightness. The first grayscale reduction occurs within the first frame after switching to DC dimming, and the second grayscale reduction occurs after the first frame. The degree of the first grayscale reduction is greater than the degree of the second grayscale reduction to improve the screen flickering issue in the first frame.

[0087] Figure 4 An example is shown illustrating the screen brightness change caused by fingerprint unlocking. For example... Figure 4As shown, before time t1, the screen brightness is L1, which is relatively low and in PWM dimming mode. At time t1, the user touches the fingerprint recognition area. In response, the screen displays a fingerprint spot in the fingerprint recognition area to illuminate the fingerprint, and the screen dimming mode switches from PWM dimming to DC dimming to facilitate fingerprint collection by the under-display fingerprint sensor. As a result, in the first frame after entering DC dimming, the screen brightness rapidly increases to the peak brightness L2, causing a sudden brightness change. To address this issue, a ratio value (denoted as ratio a) can be used in the first frame to reduce the grayscale of pixels outside the fingerprint recognition area, thereby reducing the perceived screen brightness in the first frame and making it approximately the same as the perceived screen brightness before fingerprint unlocking.

[0088] In addition, such as Figure 4 As shown, after the first frame, another ratio value (denoted as ratio b) can be used to further reduce the grayscale of pixels outside the fingerprint recognition area on the screen, so that the screen brightness perceived by the human eye before and after fingerprint unlocking is basically the same. This is because after the first frame, the screen uses DC dimming. According to the dimming logic written into the DDIC by the screen manufacturer, the condition for entering DC dimming is that the screen brightness increases to above the aforementioned preset brightness A (including preset brightness A), which will cause the screen brightness after unlocking to be higher than the screen brightness before unlocking. Therefore, ratio b can be used to reduce the grayscale of pixels outside the fingerprint recognition area on the screen, so that the screen brightness perceived by the user before and after fingerprint unlocking is stable.

[0089] In this embodiment, ratio a is lower than ratio b because the screen brightness in the first frame after DC dimming (where there is a sudden brightness change) is higher than the screen brightness after the first frame, and both are higher than the screen brightness when the screen is locked. Therefore, both can reduce the brightness perceived by the human eye by lowering the grayscale of the screen pixels, and the degree of grayscale reduction in the first frame is greater than the degree of grayscale reduction after the first frame.

[0090] In this embodiment, adjusting the grayscale of pixels on the screen using ratio a or ratio b can mean lowering the grayscale of each pixel on the screen using ratio a or ratio b, meaning the grayscale reduction is the same for all pixels. However, to convey the meaning of the image, the grayscale values ​​of each pixel are not exactly the same, and the grayscale values ​​of each pixel depend on the grayscale characteristics of the image displayed by the SOC.

[0091] like Figure 5As shown, through this embodiment, the screen brightness can remain stable and is unaffected by fingerprint unlocking. Before the user's finger touches the fingerprint recognition area 101 on the screen, the screen brightness is L1. After the user's finger touches the fingerprint recognition area 101 on the screen, the screen brightness remains at L1. Furthermore, after the user's finger touches the fingerprint recognition area 101 on the screen, the electronic device can also display a fingerprint spot 102 on the fingerprint recognition area 101. The fingerprint spot 102 is a fingerprint-like image with a specific high grayscale value (e.g., a grayscale value of 255), which significantly improves the brightness of the fingerprint recognition area 101, thereby illuminating the finger and facilitating the fingerprint sensor to collect a clear fingerprint. Subsequently, the electronic device can remove (no longer display) the fingerprint spot 102, during which time the screen brightness remains unchanged.

[0092] The "first frame" mentioned in the embodiments of this application may be more than one frame, such as two or three frames, and its duration can be determined according to the hardware characteristics of the pixel circuit. For example, if the pixel circuit needs two frames to recover to a steady state after switching from PWM dimming to DC dimming, then the "first frame" can be set to the first to second frames after entering DC dimming.

[0093] Figure 6 The overall flow of a screen brightness control method provided in an embodiment of this application is illustrated. The following is a detailed explanation:

[0094] S101. Immediately, the electronic device can control the screen to work in PWM dimming mode and display the lock screen interface.

[0095] The "first time" can be any time when the screen is in PWM dimming mode and displays the lock screen. The lock screen can be like... Figure 2 An example user interface is shown.

[0096] In some embodiments, the specific implementation of the electronic device controlling the screen to operate in PWM dimming mode at the first moment may include: the electronic device controlling the screen brightness at the first moment to be below the aforementioned preset brightness A, so as to trigger the dimming logic written into the DDIC by the screen manufacturer, thereby controlling the screen to enter PWM dimming mode. The condition for the electronic device to reduce screen brightness may be: detecting that the electronic device is in a dark environment, so as to adjust the screen brightness to adapt to the dark environment.

[0097] S102. The electronic device can detect the fingerprint recognition area within the user's touchscreen.

[0098] The fingerprint recognition area can be like Figure 2 The fingerprint recognition area 101 is shown as an example. Specifically, a fingerprint sensor may be provided below the fingerprint recognition area to collect the user's fingerprint when the user touches the fingerprint recognition area.

[0099] In some embodiments, an electronic device may increase the screen refresh rate after detecting a user's touch operation.

[0100] S103. In response to a user's touch of the fingerprint recognition area on the screen, the electronic device can control the screen to switch from PWM dimming mode to DC dimming mode, collect the fingerprint, and can use ratio a to reduce the grayscale of pixels outside the fingerprint recognition area on the screen in the first frame after the switch.

[0101] As mentioned earlier, switching the control screen from PWM dimming mode to DC dimming mode can prevent the fingerprint sensor from sensing flicker and ensure that the fingerprint sensor captures a fully lit fingerprint image.

[0102] like Figure 4 As shown, in the first frame after entering DC dimming, the screen brightness increases rapidly and then returns to normal. That is, the screen brightness undergoes a sudden change within the first frame. By using ratio 'a' to reduce the grayscale of pixels outside the fingerprint recognition area in the first frame, the perceived screen brightness can be reduced, and this can be used to control the screen brightness in the first frame to be equal to or close to the initial screen brightness.

[0103] In some embodiments, the specific implementation of the electronic device controlling the screen to switch from PWM dimming mode to DC dimming mode may include: the screen brightness of the electronic device controlling the screen to be above the aforementioned preset brightness A (including preset brightness A) to trigger the dimming logic written into the DDIC by the screen manufacturer, thereby controlling the screen to enter DC dimming mode.

[0104] S104. After the first frame of switching from PWM dimming mode to DC dimming mode, the electronic device can use ratio b to reduce the grayscale of pixels outside the fingerprint recognition area on the screen.

[0105] After the first frame, the screen brightness returns to the stable brightness of DC dimming mode. The screen brightness in DC dimming mode is higher than that in PWM dimming mode, which can cause inconsistencies in screen brightness before and after fingerprint unlocking. By using a ratio b to reduce the grayscale of pixels outside the fingerprint recognition area after the first frame, the screen brightness after the first frame can be controlled to be equal to or close to the initial screen brightness, thus improving the inconsistency in screen brightness before and after fingerprint unlocking.

[0106] In this embodiment, the application ratio 'a' within the first frame is lower than the application ratio 'b' after the first frame because the screen brightness (with a sudden brightness change) within the first frame after DC dimming is higher than the screen brightness after the first frame, and both are higher than the screen brightness when the screen is locked. Therefore, both can reduce the brightness perceived by the human eye by lowering the grayscale of the screen pixels, and the degree of grayscale reduction within the first frame is greater than the degree of grayscale reduction after the first frame.

[0107] In some embodiments, the electronic device may use ratio b to reduce the grayscale of pixels outside the fingerprint recognition area on the screen, starting at the end of the first frame.

[0108] S105. If the collected fingerprint matches the registered fingerprint, the electronic device unlocks the screen and displays the unlocked interface.

[0109] The unlocked interface can be a desktop, which may display desktop icons for one or more applications. Alternatively, the unlocked interface can be the interface displayed on the electronic device before the user locked the screen, such as the WeChat chat interface. This application does not limit the unlocked interface.

[0110] As can be seen, the embodiments of this application can solve the problem of sudden changes in screen brightness during fingerprint unlocking, so as to keep the screen brightness stable and unaffected by fingerprint unlocking.

[0111] At a specific screen refresh rate, the mapping relationship between the grayscale of pixels and brightness differs at different screen brightness levels. This can be recorded as multiple color correction curves (gamma curves) for different screen brightness levels. For example, when the screen is locked, it operates in PWM dimming mode, resulting in lower screen brightness. The mapping relationship between the grayscale of pixels and brightness can be represented by one color correction curve. After a fingerprint unlock operation is detected, the screen switches to DC dimming mode, increasing screen brightness. The mapping relationship between the grayscale of pixels and brightness can then be represented by another color correction curve.

[0112] When an electronic device switches its screen from PWM dimming mode to DC dimming mode, the gamma curve can be switched to the gamma curve corresponding to a preset brightness A. For example, before fingerprint unlocking, the screen brightness of the electronic device is L1, which is less than the aforementioned preset brightness A (the minimum screen brightness to enter DC dimming). The screen is operating in PWM dimming mode, and fingerprint acquisition is affected by the flicker of PWM. To enable the electronic device to acquire fingerprints normally, during fingerprint unlocking, the electronic device increases the screen brightness from L1 to the aforementioned preset brightness A (the minimum screen brightness to enter DC dimming), triggering the dimming logic written into the DDIC by the screen manufacturer, thereby controlling the screen to switch from PWM dimming mode to DC dimming mode. The gamma curve then switches from the gamma curve corresponding to screen brightness L1 to the gamma curve corresponding to the aforementioned preset brightness A (the minimum screen brightness to enter DC dimming).

[0113] Figure 7 The gamma curves corresponding to different screen brightness levels are shown. The unit of brightness is display brightness value (DBV). Figure 7The gamma curve 21 in the figure is the gamma curve corresponding to the screen brightness at the first moment (such as DBV800). The screen brightness at the first moment is less than the aforementioned preset brightness A (the minimum screen brightness to enter DC dimming), and the screen works in PWM dimming mode. Figure 7 The gamma curve 22 in the figure is the gamma curve corresponding to the aforementioned preset brightness A (such as DBV1000), with the screen operating in DC dimming mode. It can be seen that the larger the DBV, the greater the pixel brightness corresponding to the same grayscale value. To achieve the same pixel brightness under DBV1000 and under DBV800, this can be achieved by reducing the pixel grayscale under DBV1000.

[0114] DBV is a brightness level concept in DDIC used to describe screen brightness, and it can include 4096 levels (e.g., 0-4095 levels). The screen brightness corresponding to the gamma curve can also be represented by DBV. With a fixed grayscale level of pixels on the screen, a higher DBV indicates a brighter screen. Besides DBV, nit can also be used to describe screen brightness. The screen brightness corresponding to the gamma curve can also be represented by nit; with a fixed grayscale level of pixels on the screen, a higher nit indicates a brighter screen.

[0115] DBV and nit can be converted to each other. Please refer to the following for details. Figure 8 The description. Figure 8 This illustrates a mapping relationship between DBV and nit. For example... Figure 8 There is a mapping relationship between the DBV value and the nit value of the screen brightness. For example, the aforementioned preset brightness A can be expressed as 75 nit, or it can be expressed as the DBV value corresponding to 75 nit, such as 1000.

[0116] Assume the aforementioned preset brightness A (the minimum screen brightness for entering DC dimming) is 75 nits (DBV corresponds to 1000). If the screen brightness is below 75 nits (DBV corresponds to 1000) before fingerprint collection, the screen is operating in PWM dimming mode. Then, when collecting fingerprints, the electronic device can increase the screen brightness to 75 nits (DBV corresponds to 1000) or higher (including this number) to trigger the dimming logic written into the DDIC by the screen manufacturer, thereby controlling the screen to enter DC dimming mode.

[0117] In the first frame when the screen switches from PWM dimming mode to DC dimming mode, the electronic device can use ratio 'a' to reduce the grayscale of pixels outside the fingerprint recognition area on the screen. Then, the electronic device can determine the grayscale corresponding to the brightness of the pixel at the first moment using the gamma curve corresponding to 75 nits (DBV corresponds to 1000) from a set of gamma curves associated with the screen refresh rate 'A', and set the grayscale voltage of that pixel accordingly to control the screen brightness in the first frame to be equal to or close to the screen brightness at the first moment. Here, screen refresh rate 'A' is the screen refresh rate of the electronic device in the first frame.

[0118] After the first frame, the electronic device can use ratio b to reduce the grayscale of pixels outside the fingerprint recognition area on the screen. Then, the electronic device can determine the grayscale corresponding to the brightness of the pixels on the screen at the first moment through a set of gamma curves associated with the screen refresh rate A, specifically the gamma curve corresponding to 75 nits (DBV corresponds to 1000), and set the grayscale voltage of the pixel according to that grayscale to control the screen brightness after the first frame to be equal to or close to the screen brightness at the first moment.

[0119] Furthermore, the condition for an electronic device to use ratio 'a' to reduce the grayscale of pixels outside the fingerprint recognition area on the screen in the first frame can include detecting that the electronic device is in a low-light environment. Specifically, the electronic device can determine whether it is in a low-light environment by detecting whether the ambient light brightness is lower than a preset ambient light brightness. This low-light environment is relative to a bright light environment. For example, if the preset ambient light brightness is 50 lux, then the ambient light brightness in a low-light environment is lower than 50 lux, and the ambient light brightness in a bright light environment is higher than or equal to 50 lux. When the screen is locked, if the screen is operating in PWM dimming mode and the electronic device is in a low-light environment, then in the first frame after the electronic device switches to DC dimming mode during fingerprint unlocking, ratio 'A' can be used to reduce the pixel grayscale to maintain stable screen brightness. However, when the screen is locked, if the screen is operating in PWM dimming mode but the electronic device is in a bright light environment, then in the first frame after the electronic device switches to DC dimming mode during fingerprint unlocking, ratio 'A' can be omitted to reduce the pixel grayscale. This is because sudden changes in screen brightness in low-light environments are easily perceived by users, while sudden changes in screen brightness in bright light environments are not.

[0120] Furthermore, to more clearly illuminate the fingerprint during fingerprint unlocking, electronic devices can also display a high grayscale fingerprint-shaped image in the fingerprint recognition area on the screen to form a fingerprint light spot, which can be like... Figure 2 The fingerprint spot 102 is shown in the image. The fingerprint spot significantly improves the brightness of the fingerprint recognition area, thus facilitating the fingerprint sensor to capture a clear fingerprint. Here, a high grayscale value can refer to a grayscale value higher than the average grayscale value of the lock screen interface, for example, a high grayscale value of 255.

[0121] Furthermore, after the screen is unlocked, electronic devices can increase the screen refresh rate to respond promptly to user touch operations on the screen.

[0122] The method for determining ratio b is described below.

[0123] The ratio b can be determined based on the screen brightness at the first moment and the aforementioned preset brightness A; wherein, the greater the screen brightness at the first moment, the greater the ratio b; and the greater the aforementioned preset brightness A, the smaller the ratio b.

[0124] The relationship between the ratio b and the initial screen brightness and the preset brightness A can be satisfied by the following gamma formula: Ratio b = (Initial screen brightness / Preset brightness A) 1 / x The gamma formula mentioned above is a variation of the classic gamma formula, which is: Screen brightness = ((grayscale value / 256)) x )*L 255 Where x represents the gamma value, which can be, for example, 2.2; L 255 This indicates the brightness corresponding to grayscale 255. It is a preset value that can be determined when the electronic device leaves the factory.

[0125] An exemplary description of how an electronic device determines a ratio b based on the screen brightness at a first moment and a preset brightness A can be shown in Table 1.

[0126] Table 1

[0127]

[0128] As can be seen from Table 1 above, when the preset brightness A remains unchanged, the ratio b does not decrease as the screen brightness increases in the first instant.

[0129] Table 1 merely illustrates one exemplary data format for recording the correspondence between ratio b and the screen brightness at a first time and a preset brightness A. It is not limited to this; the recording format of this correspondence can also be other, and this application embodiment does not impose any limitations on it.

[0130] The method for determining ratio 'a' is described below.

[0131] Ratio 'a' is determined based on ratio 'b' and the screen brightness at the first moment. Specifically, given a fixed preset brightness A, ratio 'a' increases as the screen brightness at the first moment increases.

[0132] Figure 9 An example is shown where ratio a is obtained based on the screen brightness and ratio b at a first moment.

[0133] like Figure 9As shown, N binding points can be set within the PWM range, and then linear interpolation is used to calculate the ratio 'a' between the N binding points. Here, the PWM range refers to the brightness range of the screen when operating in PWM dimming mode. This PWM range can be, for example,... Figure 9 The DBV values ​​shown range from 0 to 1000. If fine-tuning of each DBV value is required, the number of binding points N can be 1000. With the PWM range values ​​and the number of binding points determined, the screen brightness at the first moment can be determined. Combining this with the explanation of obtaining the ratio b in the previous embodiment, given the ratio b and the screen brightness at the first moment are determined, an optimal ratio a can always be obtained to ensure that the screen brightness remains at the first moment's brightness before and after the fingerprint spot is displayed. This ratio a is based on empirical data obtained from multiple experiments.

[0134] Different screen modules and the initial screen brightness can affect the peak screen brightness, which in turn affects the value of ratio 'a'. Therefore, the value of ratio 'a' is influenced by the characteristics of the screen module and the initial screen brightness. Specifically, with the same screen module, the higher the initial screen brightness (i.e., the closer it is to the preset brightness A), the smaller the peak screen brightness; conversely, the lower the initial screen brightness (i.e., the further it deviates from the preset brightness A), the larger the peak screen brightness. A smaller peak screen brightness results in a larger ratio 'a'; conversely, a larger peak screen brightness results in a smaller ratio 'a'.

[0135] An exemplary description of how an electronic device determines ratio a based on ratio b and the screen brightness at a first moment can be shown in Table 2.

[0136] Table 2

[0137]

[0138] As can be seen from Table 2 above, when the preset brightness A remains unchanged, the ratio a increases as the screen brightness increases in the first instant.

[0139] Table 2 only exemplifies one data format for recording the correspondence between ratio a and ratio b, and the screen brightness at a first time. It is not limited to this; the recording format of this correspondence can also be other, and this application embodiment does not impose any limitations on it.

[0140] Sudden changes in screen brightness (also known as screen flickering) can include both scenes where the screen is brightly lit and scenes where the screen flickers dimly. In scenes where the screen is brightly lit, ratio a is less than ratio b. In scenes where the screen flickers dimly, ratio a is greater than ratio b.

[0141] This application's embodiments are also applicable to different screen modules. The electronic device can dynamically adjust the ratio 'a' and the interval frame number between ratios 'a' and 'b' at the device level based on the screen brightness peak to achieve the best effect. As mentioned above, different screen modules can affect the screen brightness peak. The smaller the screen brightness peak, the larger the ratio 'a' required in this application's embodiments; conversely, the larger the screen brightness peak, the smaller the ratio 'a' required in this application's embodiments. Furthermore, different screen brightness peaks require different amounts of time to suppress the screen brightness peak using ratio 'a'. In this way, the electronic device can flexibly accommodate the differences in screens between different module manufacturers based on the overall device solution.

[0142] For power-saving scenarios (such as low-frequency PWM for the screen), the embodiments of this application can adapt the screen brightness peak value to the different ratio c between the scenario and the normal scenario.

[0143] The peak screen brightness is as described above Figure 4 With L2 as the reference and ratio c as the reference for ratio a, an exemplary description of ratio c in the power saving scenario can be shown in Table 3.

[0144] Table 3

[0145] Power consumption mode Peak screen brightness ratio c Mild power saving mode 80％*L2 1.2*Ratio a Deep power saving mode 60％*L2 1.4*Ratio a Normal mode L2 ratio a

[0146] Table 3 above can be used to record the ratios corresponding to one or more power-saving modes. As can be seen from Table 3, the deeper the power saving, the smaller the peak screen brightness, and thus the larger the value of ratio c. Furthermore, with the same screen module, the peak screen brightness corresponding to the power saving mode is smaller than the peak screen brightness of the electronic device when it is not in power saving mode, and the ratio corresponding to each power saving mode is greater than the ratio of the electronic device when it is not in power saving mode.

[0147] Table 2 only illustrates one exemplary data format for recording the correspondence between the ratio c and the peak screen brightness and power consumption mode. It is not limited to this; the recording format of this correspondence can also be other, and this application embodiment does not impose any limitations on it.

[0148] Specifically, the electronic device can detect that it has entered a power-saving mode A, and then the ratio corresponding to power-saving mode A in Table 3 can be determined as ratio a. For example, the electronic device can detect that it has entered a light power-saving mode, and then the ratio 1.2 * ratio a corresponding to light power-saving mode in Table 3 can be determined as ratio a. The electronic device can also detect that it has entered a deep power-saving mode, and then the ratio 1.4 * ratio a corresponding to deep power-saving mode in Table 3 can be determined as ratio a.

[0149] Figure 10The signal changes applied using a screen brightness control method are illustrated. The driver layer of the electronic device can detect the synchronization signal and determine the aforementioned first frame based on the characteristics of the detected synchronization signal. For example, Figure 9 The frame rate of the first frame shown is significantly higher than that of the previous frame. After determining the first frame, the electronic device can obtain the signaling of the sent ratios a and b through the Mobile Industry Processor Interface (MIPI), and can determine the relationship between them based on the detected values ​​of ratio a and ratio b.

[0150] Figure 11 An example is shown of the software architecture of an electronic device.

[0151] A layered architecture divides software into several layers, each with a clear role and function. Layers communicate with each other through software interfaces. In some embodiments, the system is divided into five layers, from top to bottom: the application layer, the application framework layer, the system library layer, the hardware abstraction layer, and the kernel layer. Figure 11 The document also shows a hardware layer that can communicate with the kernel layer.

[0152] The application layer can include a series of application packages.

[0153] like Figure 11 As shown, the application package may include applications (also known as apps) such as camera, calendar, map, WLAN, music, gallery, call, navigation, and Bluetooth.

[0154] The application framework layer provides application programming interfaces (APIs) and programming frameworks for applications in the application layer. The application framework layer includes a set of predefined functions.

[0155] like Figure 11 As shown, the application framework layer may include a window manager, content provider, view system, phone manager, resource manager, notification manager, etc.

[0156] The window manager is used to manage windowed applications. It can retrieve screen size, determine the presence of a status bar, lock the screen, and capture screenshots, among other things.

[0157] Content providers store and retrieve data, making that data accessible to applications. This data may include videos, images, audio, made and received phone calls, browsing history and bookmarks, phone books, etc.

[0158] A view system includes visual controls, such as controls for displaying text and controls for displaying images. View systems can be used to build applications. A display interface can consist of one or more views. For example, a display interface including a text notification icon could include views for displaying text and views for displaying images.

[0159] A phone manager is used to provide communication functions for electronic devices. For example, it manages call status (including connection and disconnection).

[0160] The file explorer provides applications with various resources, such as localized strings, icons, images, layout files, video files, and more.

[0161] The notification manager allows applications to display notifications in the status bar. These notifications can be used to deliver informational messages and can disappear automatically after a short pause, requiring no user interaction. For example, the notification manager can be used to notify users of completed downloads or message alerts. The notification manager can also display notifications as icons or scrolling text in the top status bar, such as notifications from background applications, or as dialog-style notifications on the screen. Examples include displaying text messages in the status bar, emitting sounds, vibrating electronic devices, and flashing indicator lights.

[0162] The runtime consists of the core libraries and the virtual machine. The runtime is responsible for system scheduling and management.

[0163] The core library consists of two parts: one part is the functionalities that the programming language (e.g., Java) needs to call, and the other part is the system's core library.

[0164] The application layer and application framework layer run in a virtual machine. The virtual machine executes the programming files (e.g., .jave files) of the application layer and application framework layer as binary files. The virtual machine is used to perform functions such as object lifecycle management, stack management, thread management, security and exception management, and garbage collection.

[0165] System libraries can include multiple functional modules. For example: surface manager, media libraries, 3D graphics processing libraries (e.g., OpenGL ES), 2D graphics engines (e.g., SGL), etc.

[0166] The Surface Manager is used to manage the display subsystem and provides the fusion of two-dimensional (2D) and three-dimensional (3D) layers for multiple applications.

[0167] The media library supports playback and recording of various common audio and video formats, as well as still image files. It supports multiple audio and video encoding formats, such as MPEG4, H.264, MP3, AAC, AMR, JPG, and PNG.

[0168] The 3D graphics processing library is used to implement 3D graphics drawing, image rendering, compositing, and layer processing.

[0169] A 2D graphics engine is a graphics engine for 2D drawing.

[0170] The Hardware Abstraction Layer (HAL) is an interface layer located between the operating system kernel layer and other layers of electronic devices (such as the local service layer). Its purpose is to abstract hardware and provide a virtual hardware platform for the operating system.

[0171] The hardware abstraction layer includes modules such as the fingerprint hardware abstraction layer.

[0172] The fingerprint hardware abstraction layer can be used to receive events corresponding to user touch operations on the fingerprint recognition area within the screen from the fingerprint driver, and to notify the display driver of the touch operation.

[0173] The kernel layer is the layer between hardware and software. It can also be called the driver layer. The kernel layer can include modules such as fingerprint drivers, touch drivers, and display drivers.

[0174] The touch driver can be used to receive events corresponding to touch operations sent by the screen and transmit the events corresponding to the touch operations to the fingerprint driver.

[0175] The fingerprint driver can be used to receive events corresponding to touch operations from the touch driver and pass the events to the fingerprint hardware abstraction layer.

[0176] The fingerprint driver can also be used to send message A to the fingerprint sensor, which in turn drives the fingerprint sensor to acquire a fingerprint.

[0177] The display driver can be used to control the screen to switch from PWM dimming mode to DC dimming mode after receiving a notification from the fingerprint hardware abstraction layer, in order to cooperate with the fingerprint sensor to collect fingerprints. Specifically, the display driver can increase the screen brightness to a preset brightness A or higher (including the preset brightness A) to trigger the dimming logic written into the DDIC by the screen manufacturer, thereby controlling the screen to enter DC dimming mode.

[0178] The display driver can also be used to control electronic devices to reduce the grayscale of pixels outside the fingerprint recognition area on the first frame after switching from PWM dimming mode to DC dimming mode, so that the brightness of the screen in the first frame is equal to or close to the screen brightness at the first moment.

[0179] The display driver can also be used to control the use of ratio b to reduce the grayscale of pixels outside the fingerprint recognition area on the screen after the first frame, so that the brightness of the screen after the first frame is equal to or close to the screen brightness at the first moment.

[0180] The hardware layer can include hardware devices such as screens, fingerprint sensors, and DDICs.

[0181] The screen can be used to detect user touches on the fingerprint recognition area within the screen and pass the event corresponding to the touch operation to the touch driver in the kernel layer.

[0182] A fingerprint sensor can be used to receive message A from a fingerprint driver and collect a fingerprint based on message A.

[0183] DDIC can be connected to a screen and can be used to improve the screen refresh rate.

[0184] DDIC can also be used to display fingerprint images with high grayscale values ​​(such as a grayscale value of 255) in the fingerprint recognition area to form a fingerprint spot, which helps the fingerprint sensor to collect clear fingerprints.

[0185] For exemplary descriptions of other hardware devices at the hardware layer, please refer to the foregoing. Figure 1 The description is omitted here.

[0186] This application also provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, it can implement the steps performed by the electronic device in the above method embodiments, or the steps performed by the human-computer interaction module and the computing module.

[0187] This application also provides a computer program product that, when run on a terminal device, enables the terminal device to perform the steps executed by the electronic device in the above method embodiments.

[0188] This application also provides a chip system, which includes a processor coupled to a memory. The processor executes a computer program stored in the memory to implement the steps performed by the electronic device in any of the method embodiments of this application. The chip system can be a single chip or a chip module composed of multiple chips.

[0189] The term "user interface (UI)," or simply "interface," used in the specification and accompanying drawings of this application, refers to the medium through which an application or operating system interacts and exchanges information with the user. It facilitates the conversion between the internal form of information and a form acceptable to the user. The user interface of an application is written in source code using specific computer languages ​​such as Java or Extensible Markup Language (XML). This source code is parsed and rendered on the terminal device, ultimately presenting user-recognizable content, such as images, text, and buttons. Controls, also known as widgets, are the basic elements of the user interface. Typical controls include toolbars, menu bars, text boxes, buttons, scroll bars, images, and text. The attributes and content of controls in the interface are defined using tags or nodes, such as XML tags. <textview> 、 <imgview> 、 <videoview>Nodes define the controls contained in the interface. A node corresponds to a control or property in the interface, and after parsing and rendering, the node is presented as the content visible to the user. In addition, many applications, such as hybrid applications, often contain web pages within their interfaces. A web page, also known as a webpage, can be understood as a special control embedded in the application interface. Web pages are source code written in a specific computer language, such as Hypertext Markup Language (HTML), Cascading Style Sheets (CSS), JavaScript (JS), etc. Web page source code can be loaded and displayed as user-readable content by a browser or a web page display component with browser-like functionality. The specific content contained in a webpage is also defined through tags or nodes in the webpage source code; for example, HTML uses tags or nodes to define the content. 、 、 <video> 、 <canvas>To define the elements and attributes of a webpage.

[0190] The most common form of user interface is the graphical user interface (GUI), which refers to a user interface related to computer operation displayed graphically. It can be an icon, window, control, or other interface element displayed on the screen of an electronic device. Controls can include visual interface elements such as icons, buttons, menus, tabs, text boxes, dialog boxes, status bars, navigation bars, and widgets.

[0191] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid-state drive), etc.

[0192] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. This program can be stored in a computer-readable storage medium, and when executed, it can include the processes described in the above method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as ROM or random access memory (RAM), magnetic disks, or optical disks.

[0193] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.< / canvas> < / video> < / videoview> < / imgview> < / textview>

Claims

1. A screen brightness control method, applied to electronic devices, characterized in that, The electronic device includes a screen and a fingerprint sensor, the fingerprint sensor being disposed below the screen; the method includes: The electronic device controls the screen to operate in pulse width modulation (PWM) dimming mode and displays the lock screen interface; The electronic device detects that the user touches the fingerprint recognition area within the screen; The electronic device controls the screen to switch from the PWM dimming mode to the DC dimming mode, controls the fingerprint sensor to collect fingerprints, and uses a first ratio to reduce the grayscale of pixels outside the fingerprint recognition area on the screen in the first frame after the switch. After the first frame, the electronic device uses a second ratio to reduce the grayscale of pixels outside the fingerprint recognition area on the screen; If the collected fingerprint matches the registered fingerprint, the electronic device unlocks the screen; Wherein, the first ratio is lower than the second ratio, and the grayscale reduction of the first frame is greater than the grayscale reduction of subsequent frames.

2. The method according to claim 1, characterized in that, After detecting that a user has touched the fingerprint recognition area within the screen, the method further includes: The electronic device displays a fingerprint spot image of a first gray level in the fingerprint recognition area, the first gray level being higher than the average gray level of the lock screen interface.

3. The method according to claim 1 or 2, characterized in that, The second ratio is determined based on the first screen brightness and the second screen brightness; wherein, the first screen brightness is the minimum screen brightness at which the screen enters the DC dimming mode; the second screen brightness is the screen brightness when the electronic device controls the screen to work in the PWM dimming mode; the higher the first screen brightness, the lower the second ratio; the higher the second screen brightness, the higher the second ratio.

4. The method according to claim 3, characterized in that, The relationship between the second ratio and the first screen brightness, and the second screen brightness, satisfies the following gamma formula: Second ratio = (Second screen brightness / First screen brightness) 1 / x , where x represents the gamma value.

5. The method according to claim 1, characterized in that, The first ratio is determined based on the second ratio and the second screen brightness; wherein, the second screen brightness is the screen brightness when the electronic device controls the screen to work in the PWM dimming mode; the greater the second screen brightness, the greater the first ratio.

6. The method according to claim 1, characterized in that, The electronic device controls the screen to operate in pulse width modulation (PWM) dimming mode, specifically including: The electronic device controls the screen brightness to be below a first screen brightness, which is the minimum screen brightness at which the screen enters the DC dimming mode.

7. The method according to claim 1, characterized in that, The electronic device controls the screen to switch from the PWM dimming mode to the DC dimming mode, specifically including: The electronic device controls the screen brightness to be above a first screen brightness, which is the minimum screen brightness at which the screen enters the DC dimming mode.

8. The method according to claim 1, characterized in that, Before reducing the grayscale of pixels outside the fingerprint recognition area on the screen using the first ratio, the method further includes: The electronic device detected that it was in a low-light environment.

9. The method according to claim 1, characterized in that, The method further includes: The electronic device detects that it has entered a first power-saving mode; The ratio corresponding to the first power-saving mode in the first table is determined as the first ratio; The first table is used to record the ratio corresponding to one or more power saving modes; the ratio corresponding to each power saving mode is greater than the ratio of the electronic device not entering the power saving mode.

10. The method according to claim 1, characterized in that, The electronic device further includes: a fingerprint sensor and a display driver integrated circuit (DDIC); the DDIC is connected to the screen; the electronic device runs a first software system, which includes: a touch driver, a fingerprint driver, a display driver, and a fingerprint hardware abstraction layer; The screen is used to detect a first operation by the user touching the fingerprint recognition area within the screen, and to transmit the event corresponding to the first operation to the touch driver; The touch driver is used to transmit the event corresponding to the first operation to the fingerprint driver; The fingerprint driver is used to control the fingerprint sensor to collect a fingerprint after receiving an event corresponding to the first operation; The fingerprint driver is also used to pass the event corresponding to the first operation to the fingerprint hardware abstraction layer; The fingerprint hardware abstraction layer is used to notify the display driver of the first operation; The display driver is configured to, upon learning of the first operation, control the DDIC to switch the screen from the PWM dimming mode to the DC dimming mode, reduce the grayscale of pixels outside the fingerprint recognition area on the screen using the first ratio in the first frame after the switch, and reduce the grayscale of pixels outside the fingerprint recognition area on the screen using the second ratio after the first frame; the first ratio is less than the second ratio.

11. The method according to claim 10, characterized in that, The display driver is also configured to, upon learning of the first operation, control the DDIC to display a fingerprint spot image of a first grayscale in the fingerprint recognition area, wherein the first grayscale is higher than the average grayscale of the lock screen interface.

12. The method according to claim 10 or 11, characterized in that, The display driver is also used to control the DDIC to increase the screen refresh rate after knowing the first operation.

13. The method according to claim 1, characterized in that, After detecting that a user has touched the fingerprint recognition area within the screen, the method further includes: The electronic device increases the screen refresh rate.

14. The method according to claim 1, characterized in that, The first frame may include one or more frames.

15. The method according to claim 1, characterized in that, The screen is an organic light-emitting diode (OLED) screen.

16. An electronic device, characterized in that, include: The screen, fingerprint sensor, processor, and memory are included; the fingerprint sensor is disposed below the screen; the screen operates in pulse width modulation (PWM) dimming mode when the screen brightness is lower than a first screen brightness, and operates in direct current (DC) dimming mode when the screen brightness is higher than the first screen brightness; the first screen brightness is the minimum screen brightness at which the screen enters the DC dimming mode. The screen, the fingerprint sensor, and the memory are coupled to the processor. The memory is used to store computer program code, which includes computer instructions. The processor invokes the computer instructions to cause the electronic device to perform the method as described in any one of claims 1-15.

17. A computer-readable storage medium comprising instructions, characterized in that, When the instructions are executed on an electronic device, the electronic device causes the electronic device to perform the method as described in any one of claims 1-15.

18. A chip system applied to an electronic device, characterized in that, The chip system includes one or more processors, which are configured to invoke computer instructions to cause the electronic device to perform the method as described in any one of claims 1-15.

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