Voice coil motor control method and device, camera module and electronic equipment

Abstract

The invention provides a voice coil motor control method and device, a camera module and electronic equipment, and is applied to the technical field of camera shooting. The method comprises the steps that in response to a power indication signal of a camera module, a current gain value and a target gain value of a voice coil motor are acquired, and the target gain value corresponds to a target position of a lens carrier in the voice coil motor; gradually reducing the gain value from the current gain value to a target gain value in the process of moving the lens carrier to the target position; and generating a driving signal based on the reduced gain value, and controlling the lens carrier to move to a target position. According to the embodiment of the invention, the lens can be simply, efficiently and stably reset to the target position, so that impact is reduced, and impact noise can be reduced.

Description

Technical Field

[0001] The present disclosure relates to the field of camera technology, and in particular to a voice coil motor control method, device, camera module, and electronic equipment. Background Art

[0002] With the increasing popularity of electronic devices such as smartphones, tablets, and laptops, integrated camera modules have become standard components. As the core driver of camera modules, voice coil motors (VCMs) use electromagnetic force to control the movement of the lens and lens carrier along the optical axis, enabling focus and optical image stabilization.

[0003] When the camera module loses power, the electromagnetic support of the voice coil motor (VCM) instantly disappears, causing the lens carrier to undergo uncontrolled movement due to the inherent forces of the mechanical structure. Specifically, in a ball-bearing VCM structure, the lens carrier falls freely due to gravity; in a shrapnel-type VCM structure, the carrier rebounds due to the restoring force of the shrapnel. This movement causes the lens carrier to strike the VCM frame, generating a mechanical impact. Furthermore, because the impact point is close to the device microphone, this noise is easily picked up and amplified, significantly affecting the user experience.

[0004] To suppress impact noise, related technical solutions rely on the accelerometer in the gyroscope to provide a gravity acceleration signal. The gravity acceleration vector is then used to calculate the natural position of the lens in a static environment. The lens carrier is then controlled to move to that position before powering off, shortening the impact stroke to reduce impact noise. However, this solution requires calculating the direction of gravity in conjunction with the gravity signal from the gyroscope to determine the lens's movement trajectory and target position, resulting in a relatively complex algorithm. Furthermore, if the electronic device is shaken, the dynamic change in the direction of gravity can easily lead to system misjudgment, resulting in unexpected results.

[0005] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute prior art known to ordinary technicians in the field. Summary of the Invention

[0006] The present disclosure provides a voice coil motor control method, device, camera module and electronic equipment, which do not require obtaining a gravity acceleration signal from a gyroscope device, nor do they require complex calculations of the target position based on the gravity acceleration signal. At the same time, they effectively avoid misjudgment of the target position due to changes in the direction of gravity, and can simply and efficiently reset the lens to the target position smoothly to reduce impact noise.

[0007] Other features and advantages of the present disclosure will become apparent from the following detailed description, or may be learned in part by practice of the present disclosure.

[0008] According to one aspect of the present disclosure, a voice coil motor control method is provided, comprising: obtaining a current gain value and a target gain value of the voice coil motor in response to a power indication signal from a camera module, wherein the target gain value corresponds to a target position of a lens carrier in the voice coil motor; gradually reducing the gain value from the current gain value to the target gain value during movement of the lens carrier toward the target position; and generating a drive signal based on the reduced gain value to control the movement of the lens carrier to the target position.

[0009] In some embodiments, gradually reducing the gain value from the current gain value to the target gain value includes: gradually reducing the gain value from the current gain value to the target gain value within a preset time period.

[0010] In some embodiments, gradually reducing the gain value from the current gain value to the target gain value includes: gradually reducing the gain value from the current gain value to the target gain value based on a step-by-step manner; or, gradually reducing the gain value from the current gain value to the target gain value based on a constant rate; or, gradually reducing the gain value from the current gain value to the target gain value based on a non-constant rate.

[0011] In some embodiments, gradually reducing the gain value from the current gain value to the target gain value based on a non-constant rate includes: in a first stage of movement of the lens carrier, gradually reducing the gain value from the current gain value at a first rate; and in a second stage of movement of the lens carrier, reducing the gain value at a second rate until the gain value reaches the target gain value, wherein the first rate is greater than the second rate.

[0012] In some embodiments, gradually reducing the gain value from the current gain value to the target gain value based on a non-constant rate comprises: in at least one stage of the movement of the lens carrier, the non-constant rate decreases in real time over time.

[0013] In some embodiments, the method further includes: acquiring parameter information of the camera module; and gradually reducing the gain value from the current gain value to the target gain value according to the parameter information of the camera module.

[0014] In some embodiments, gradually reducing the gain value from the current gain value to the target gain value includes: gradually reducing the gain value from the current gain value to the target gain value under a phase margin constraint.

[0015] In some embodiments, after generating a driving signal based on the reduced gain value and controlling the lens carrier to move to the target position, the method further includes: cutting off the power supply of the camera module.

[0016] In some embodiments, the method for obtaining the power indication signal includes at least one of the following: receiving a power-off indication of the camera module from the control module; or, receiving a power-off signal of the camera module from the control module; or, detecting the power status of the camera module.

[0017] According to another aspect of the present disclosure, a voice coil motor control device is provided, including: a drive module configured to obtain a current gain value and a target gain value of the voice coil motor in response to a power indication signal from a camera module, wherein the target gain value corresponds to a target position of a lens carrier in the voice coil motor; gradually reduce the gain value from the current gain value to the target gain value during movement of the lens carrier toward the target position; and generate a drive signal based on the reduced gain value to control the lens carrier to move to the target position.

[0018] In some embodiments, the system further includes: a control module configured to send a power-off indication of the camera module to the driving module; or output a power-off signal of the camera module to the driving module.

[0019] In some embodiments, the driving module includes a peripheral circuit; the peripheral circuit is configured to set the current gain value and the target gain value.

[0020] In some implementations, the driving module includes a gain module having a built-in control circuit; the built-in control circuit of the gain module is configured to set the current gain value and the target gain value.

[0021] According to another aspect of the present disclosure, a camera module is also provided, comprising a lens and a voice coil motor control device as described in any one of the above.

[0022] According to another aspect of the present disclosure, an electronic device is provided, comprising: a processor; and a memory for storing executable instructions of the processor; wherein the processor is configured to execute any one of the above-mentioned voice coil motor control methods by executing the executable instructions.

[0023] According to another aspect of the present disclosure, a computer program product is provided, including: a computer program or instructions, wherein when the computer program or instructions are executed by a processor, any one of the above-mentioned voice coil motor control methods is implemented.

[0024] The embodiments of the present disclosure provide a voice coil motor control method, device, camera module, and electronic device. The method includes: obtaining a current gain value and a target gain value of the voice coil motor in response to a power indication signal of the camera module, wherein the target gain value corresponds to the target position of the lens carrier in the voice coil motor; gradually reducing the gain value from the current gain value to the target gain value during the movement of the lens carrier toward the target position; and generating a drive signal based on the reduced gain value to control the movement of the lens carrier to the target position. The embodiments of the present disclosure generate a drive signal by dynamically adjusting the gain value to control the movement of the lens carrier to the target position. There is no need to obtain a gravity acceleration signal from a gyroscope device, nor is there a need to perform complex calculations on the target position using the gravity acceleration signal. At the same time, it effectively avoids misjudgment of the target position due to changes in the direction of gravity, and can simply and efficiently reset the lens to the target position smoothly to reduce impact and also reduce impact noise.

[0025] It is to be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings are incorporated into and constitute a part of the specification, illustrate embodiments consistent with the present disclosure, and together with the specification, are used to explain the principles of the present disclosure. Obviously, the drawings described below are only some embodiments of the present disclosure, and those skilled in the art can derive other drawings based on these drawings without inventive effort.

[0027] Figure 1A One of the schematic diagrams showing a voice coil motor control device according to an embodiment of the present disclosure; Figure 1B A second schematic diagram showing a voice coil motor control device according to an embodiment of the present disclosure; Figure 1C A third schematic diagram showing a voice coil motor control device according to an embodiment of the present disclosure; Figure 1D A fourth schematic diagram showing a voice coil motor control device according to an embodiment of the present disclosure; Figure 2 A method flow chart showing a method for controlling a voice coil motor according to an embodiment of the present disclosure is shown; Figure 3 A schematic diagram of the structure of a voice coil motor assembly according to an embodiment of the present disclosure is shown; Figure 4A One of the flow charts of a method for gradually reducing a gain value from a current gain value to a target gain value in an embodiment of the present disclosure is shown; Figure 4BA second flow chart of a method for gradually reducing a gain value from a current gain value to a target gain value is shown in an embodiment of the present disclosure; Figure 5 A third flow chart of a method for gradually reducing a gain value from a current gain value to a target gain value is shown in an embodiment of the present disclosure; Figure 6 A schematic diagram showing a relationship curve between frequency and gain value in an embodiment of the present disclosure is shown; Figure 7 A fourth flowchart of a method for gradually reducing a gain value from a current gain value to a target gain value is shown in an embodiment of the present disclosure; Figure 8 A schematic diagram of a camera module in an embodiment of the present disclosure is shown; Figure 9 A schematic diagram of an electronic device in an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0028] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be embodied in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concepts of the example embodiments to those skilled in the art. The described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0029] The features, structures or characteristics described in the present disclosure may be combined in any suitable manner in one or more embodiments. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced while omitting one or more of the specific details, or other methods, components, devices, steps, etc. may be adopted. In other cases, known methods, devices, implementations or operations are not shown or described in detail to avoid obscuring various aspects of the present disclosure.

[0030] In addition, the accompanying drawings are merely schematic illustrations of the present disclosure and are not necessarily drawn to scale. Identical reference numerals in the figures denote identical or similar parts, and thus repetitive descriptions thereof will be omitted. Some of the block diagrams shown in the accompanying drawings are functional entities that do not necessarily correspond to physically or logically separate entities. These functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0031] The flowcharts shown in the accompanying drawings are for illustrative purposes only and do not necessarily include all content and steps, nor must they be executed in the order described. For example, some steps may be decomposed, while others may be combined or partially combined. Therefore, the actual execution order may vary depending on the actual situation.

[0032] In this specification, the terms "a", "an", "the", "said" and "at least one" are used to indicate the presence of at least one element / component / etc.; the terms "comprising", "including" and "having" are used to express open-ended inclusion and mean that additional elements / components / etc. may exist in addition to the listed elements / components / etc.; the terms "first", "second" and "third" etc. are used only as labels and are not intended to limit the quantity of their objects.

[0033] The specific implementation of the embodiment of the present disclosure is described in detail below with reference to the accompanying drawings.

[0034] like Figure 1A As shown in FIG, it is a schematic diagram of a voice coil motor control device provided by an embodiment of the present disclosure. Figure 1A As shown, the present disclosure provides a voice coil motor control device 1 including a driving module 10, which controls the voice coil motor 20 to drive the lens carrier of the camera module to move and smoothly reset the lens carrier to the target position. The voice coil motor control device of the present disclosure can be applied to electronic devices with a camera module, such as mobile phones, laptops, tablet computers, etc., and the camera module may include a voice coil motor frame and a lens carrier, and the lens carrier is used to fix and support the lens. The voice coil motor driving module 10 of the present disclosure is mainly electrically connected to the voice coil motor of the camera module of the electronic device. The current gain value and target gain value of the voice coil motor are obtained to control the movement of the lens carrier of the camera module accordingly. It should be noted that the driving module 10 can be a separate driving chip, which is set separately from the voice coil motor 20. The driving module 10 can also be coupled to the voice coil motor 20. Specifically, the driving module is configured to obtain the current gain value and target gain value of the voice coil motor in response to the power indication signal of the camera module, wherein the target gain value corresponds to the target position of the lens carrier in the voice coil motor; during the process of the lens carrier moving toward the target position, the gain value is gradually reduced from the current gain value to the target gain value; and a driving signal is generated based on the reduced gain value to control the lens carrier to move to the target position.

[0035] See also Figure 1BAs shown, the driving module 10 provided by the embodiment of the present disclosure includes an analog-to-digital converter 11, a PID controller 12, a gain module 13, a digital-to-analog converter 14, and a driving unit 15. A first end of the analog-to-digital converter 11 is connected to a first end of the voice coil motor 20, and another end of the analog-to-digital converter 11 is connected to a first end of the PID controller 12. The first end of the PID controller 12 is connected to a first end of the gain module 13. A second end of the gain module 13 is connected to a first end of the digital-to-analog converter 14. A second end of the digital-to-analog converter 14 is connected to a first end of the driving unit 15, and a second end of the driving unit 15 is connected to a second end of the voice coil motor 20. In response to a power indication signal from the camera module, the gain module 13 gradually reduces the gain value from a current gain value to a target gain value. Based on the reduced gain value, a driving signal is generated and output to the digital-to-analog converter 14. The digital-to-analog converter 14 converts the digital signal output by the gain module 13 into an analog signal, which is then output to the driving unit 15. The driving unit 15 generates a driving current based on the received analog signal, which is applied to the voice coil motor, causing the voice coil motor to drive the lens carrier to a target position. Here, the driving unit 15 may be a driving circuit or a chip. When the driving unit 15 is a driving circuit, the driving circuit may specifically be an H-bridge circuit.

[0036] It should be noted that the setting of the gain value is completed automatically. The target gain value can be set by default to zero or a minimum value close to zero, such as ±5dB or ±1dB; or the target position corresponds to the required gain value. In some embodiments, the driving module 10 includes a peripheral circuit; the peripheral circuit is configured to set the current gain value and the target gain value. In some embodiments, the gain module 13 has a built-in control circuit; the built-in control circuit of the gain module 13 is configured to set the current gain value and the target gain value, for example, the gain value setting can be controlled by a program pre-burned in the circuit of the gain module 13.

[0037] In some embodiments, see Figure 1C As shown, the driving module 10 provided in the embodiment of the present disclosure also includes a set value setting unit 16 for setting the parameter value of the voice coil motor, for example, setting the target position of the lens carrier in the scenario of servo-off slow-down processing. It should be noted that in this embodiment, the hardware configuration of the set value input unit does not need to be changed, and the input value setting is supported. The input value is set by the user platform via the IIC interface. It should be noted that since this embodiment realizes the slow-down processing of the lens carrier by automatically adjusting the gain value of the gain module 13, there is no need for the analog-to-digital converter 11 to provide position feedback, nor is there a need for the PID controller 12 and the set value setting unit 16 to perform modulation.

[0038] In some embodiments, see Figure 1DAs shown, the driver module 10 provided in this embodiment of the present disclosure also includes a target value setting unit 17, which is used to set the parameter values ​​of the voice coil motor when the servo is enabled, ensuring that the voice coil motor smoothly supports lens zoom. It will be understood that when servo mode is enabled, to ensure that the lens moves to a specific zoom position, the current gain value of the gain module 13 corresponds to the current position of the lens carrier. During subsequent power-off, the gain module 13 can directly use this current gain value to drive the lens carrier for a smooth landing, without the need to obtain additional position information of the lens carrier.

[0039] In some embodiments, the output value of the DAC 14 can also be temporarily stored in a register for the driving unit 15 circuit to adjust the driving current applied to the voice coil motor, thereby prompting the voice coil motor to drive the lens carrier to move to the target position.

[0040] In some embodiments, the voice coil motor control device further includes a control module 30, which is connected to the driver module 10. The control module 30 is configured to send a power-off instruction to the driver module 10 for the camera module; or, alternatively, to output a power-off signal for the camera module to the driver module 10. It should be noted that the control module 30 can be configured independently, for example, as a control chip for the camera module or a control chip for an electronic device, or it can be integrated into the same driver chip as the driver module 10. In addition, the control module 30 can also be integrated into other control chips of the electronic device, such as the main control chip or peripheral control chip of the electronic device; wherein the peripheral control chip may include the control chip of each peripheral sensor of the electronic device, or the control chip of the display screen.

[0041] The following describes each step of the voice coil motor driving method disclosed in the present invention one by one. Figure 2 As shown, the voice coil motor control method disclosed herein may include the following steps: S202 , in response to a power indication signal from the camera module, obtaining a current gain value and a target gain value of the voice coil motor.

[0042] In this embodiment, the camera module's power indication signal is used to trigger the voice coil motor driver module to cut off power. Specifically, the power indication signal can include information about specific power state changes. Its function is to transmit relevant instructions to drive the system to power off or transition to a low-power state, ultimately leading to a power outage. In the camera module scenario, when this signal triggers a power outage, the electromagnetic support force of the voice coil motor is instantly lost, making the lens carrier susceptible to uncontrolled movement due to the inherent forces of the mechanical structure.

[0043] In some embodiments, the power indication signal may include a power-off signal or a power-down indication. Specifically, the power indication signal is directly related to the voice coil motor's power-off process and serves as the key signal for triggering the voice coil motor's power-off. For example, when a device receives a camera module shutdown command, the system issues a signal directly initiating the power-off process, prompting the camera module's hardware, including the voice coil motor, to terminate operation and cut off power. A power-down indication is a predictive power-off signal. For example, in response to a user command, the system issues an indication that a power-off will be executed within a short period of time, allowing time for the driver module to complete a smooth shutdown. Ultimately, the goal is to trigger a power-off.

[0044] In some embodiments, the power indication signal may also include a signal or indication for switching from high power to low power. This signal serves as a pre-emptive signal for a power outage, preparing for subsequent power outages and enabling lens reset in conjunction with the dynamic gain adjustment mechanism. When the camera module is operating at high power, the system generates a drive signal to control lens reset by dynamically adjusting the gain value after issuing this signal.

[0045] Reference Figure 3 The schematic diagram of a voice coil motor assembly structure is shown. When the camera module is powered off, the lens carrier 21 in the voice coil motor loses its electromagnetic support. Under the action of restoring forces such as gravity (ball voice coil motor) or spring force (shrapnel voice coil motor), it freely falls or rebounds quickly and hits its mechanical limit, such as Figure 3 The target position is also called the natural position, which refers to the final static equilibrium point reached by the lens carrier when it is completely unaffected by electromagnetic forces and is only affected by passive physical forces such as gravity and spring force. In addition, the target position can also refer to the stable position to which the lens carrier automatically returns after the system is powered off, that is, the power-off zero position, which usually coincides with or is closely related to the natural position. At the same time, the initial static position of the lens carrier before the system is powered on, that is, the power-on initial position, can also be regarded as a default target position reference point, and the present disclosure does not impose any restrictions on this.

[0046] It should be noted that the final static equilibrium point is usually determined by the mechanical structure of the voice coil motor, such as the lowest point of the ball voice coil motor and the spring preload equilibrium point of the shrapnel voice coil motor. The target position can specifically be the final static equilibrium point or a position infinitely close to the final static equilibrium point. When the lens carrier is in the target position, even if the lens carrier 21 loses electromagnetic force support, it will not collide with its mechanical limit and make noise, or even if it loses electromagnetic force support, since the distance from the target position to the mechanical limit is shortened, the lens carrier 21 falls from the target position to the mechanical limit, which can also reduce the impact noise. The embodiment of the present disclosure does not limit the specific target position value.

[0047] Gain is a measure of signal amplification. In a voice coil motor system, gain characterizes the system's response to changes in input current, specifically the ratio between the change in input current and the change in output force. By adjusting the gain parameter, the support force exerted by the voice coil motor on the lens assembly can be precisely controlled, thereby achieving precise control of the lens position. The current gain value specifically refers to the actual gain value of the voice coil motor under a specific operating state (including time and spatial position). The target gain value corresponds to the target position of the lens carrier in the voice coil motor. This is the gain value at or as close to the final static equilibrium point as possible, when the lens carrier is subjected to passive mechanical forces such as gravity and spring preload, without electromagnetic forces acting.

[0048] It should be noted that the gain module in this embodiment is not a new component; even if the power-off operation is not performed, the system still requires the gain module. Its primary function is to adjust the output gain of the PID controller, thereby changing the control current of the voice coil motor to achieve autofocus and optical image stabilization in the camera module. Therefore, this embodiment can obtain the current gain value of the voice coil motor in real time. Furthermore, since the target position is determined by the mechanical structure of the voice coil motor and is generally fixed, the target gain value can be pre-set.

[0049] In some embodiments, there are multiple possible ways to obtain the power indication signal. In some embodiments, the acquisition of the power indication signal may include: receiving the power-off indication of the camera module from the control module, which means that the driving module receives an instruction from the control module that clearly instructs the camera module to perform a power-off operation. The instruction is usually a control command with a specific format and content. After receiving it, the driving module will start the corresponding power-off process. It should be noted that the power-off indication can be actively triggered by the user through the operation interface. This embodiment can respond to the user's control intention, reduce erroneous operations, enable the power-off process to be started in an orderly manner according to the preset program, and improve power reliability.

[0050] In some embodiments, acquiring the power indication signal may include receiving a power-off signal from the camera module from the control module. Specifically, the driver module acquires an electrical signal transmitted from the control module to trigger powering off the camera module. This signal may be a specific voltage signal, current signal, or the like, and transmits the power-off indication through changes in the electrical signal. In this embodiment, transmitting the power-off indication via an electrical signal provides a fast response and can trigger the power-off operation in a short period of time.

[0051] In some embodiments, obtaining a power indication signal may include detecting the power status of the camera module. That is, the driver module actively monitors the real-time power status of the camera module. This monitoring can be achieved through a power status sensor or detection circuit integrated into the camera module. Based on the real-time monitoring results, the driver module accurately identifies specific power status change events, which serve as power indication signals to trigger the subsequent lens reset control process. The power status may include a power-off control state, which directly indicates that the system is about to or is in the process of powering off. The power status may also include a power mode switching state, which indicates that the system is switching between different power modes (such as high power mode and low power mode). In this embodiment, the driver module determines the power-off status by actively monitoring the power status, and can grasp the power-off requirements of the camera module in real time without relying on active transmission from an external control module. This enhances the autonomy and independence of the system, can respond to power-off requirements when abnormalities occur in the control module, and improves the stability of the entire system.

[0052] In some embodiments, an intermediate waiting state or idle state ("Idle state") can be introduced during the switch from high-power mode to low-power mode to ensure smooth and reliable control. Specifically, when the driver module detects a need to enter low-power operation (such as when the device is in standby mode or image acquisition has concluded), it first switches the camera module from high-power operation to an intermediate waiting state or idle state. In this state, the camera module's core functions are suspended, but basic power supply and communication capabilities are maintained. The module then waits for and receives the necessary low-power mode configuration signals or parameters, triggering the subsequent lens reset control process. By introducing an intermediate waiting state or idle state during the power switching process, this embodiment completes the necessary parameter configuration and status confirmation before executing the lens reset operation, thereby ensuring that the generation of the drive signal is synchronized with the power management strategy. This method not only achieves efficient and smooth control of lens motion and effectively reduces mechanical impact during movement, but also reduces structural vibration and noise caused by abrupt movements, thereby improving user experience and system reliability.

[0053] S204 : During the process of the lens carrier moving toward the target position, gradually reducing the gain value from the current gain value to the target gain value.

[0054] In this embodiment, as the lens carrier moves toward its target position (natural position), the driver module presets a current gain value and a target gain value. The gain value's changing characteristics are independent of the lens carrier's real-time position. After the movement is initiated, the driver module gradually decreases the gain value from the current gain value to the target gain value at a predetermined fixed gradient or time interval. As the gain value decreases, the control current output to the voice coil motor decreases, gradually weakening the control support force on the voice coil motor. The lens carrier descends smoothly during this process, and when the gain value reaches the target gain value, the lens carrier arrives at the natural position.

[0055] S206 , generating a driving signal based on the reduced gain value to control the lens carrier to move to a target position.

[0056] In this embodiment, the drive signal may be a drive current, which decreases as the gain value decreases, ensuring smooth movement of the lens carrier. When the gain value reaches the target gain value, the drive current approaches or reaches zero, and the lens is stably docked at the target position.

[0057] In some embodiments, after a drive signal is generated based on the reduced gain value and the lens carrier is controlled to move to a target position, the method further includes: cutting off the power supply of the camera module. In this embodiment, the target position is the natural position. When a drive signal is generated based on the reduced gain value and the lens carrier is controlled to move to the natural position, in response to the gain value having dropped to the target value and / or the drive current approaching zero, a power-off indication is generated, triggering the power management unit to cut off the power supply circuit of the camera module, thereby powering off the drive module and the voice coil motor together. Since the lens carrier has moved to the natural position, powering off at this time can reduce the noise generated by the collision between the lens carrier and the mechanical limit.

[0058] In this embodiment, there's no need to rely on the accelerometer signals in the gyroscope assembly for a complex natural position calculation process. Instead, the output current of the voice coil motor is reduced by lowering the gain value, gradually weakening the support force on the lens carrier and allowing the lens to smoothly return to its natural position. This reduces impact and noise, resulting in a simple, effective, and low-cost solution. Furthermore, because the disclosed embodiment eliminates the need for complex natural position calculations based on the accelerometer signals in the gyroscope assembly, it can overcome gyroscope misjudgments caused by shaking, preventing the motor from deviating from its natural point. This avoids the potential adverse effects of traditional solutions and improves reliability.

[0059] In some embodiments, Figure 4A As shown, in the embodiment of the present disclosure, gradually reducing the gain value from the current gain value to the target gain value may include the following steps: S402: gradually reducing the gain value from the current gain value to the target gain value within a preset time period.

[0060] In this embodiment, the driver module can set a preset time period when the lens carrier moves toward the target position (natural position). It is understood that this preset time period is relatively short, such as 100ms, during which the gain value is gradually reduced from the current gain value to the target gain value. During this process, the change in gain value is correlated with the preset time period. As the gain value gradually decreases according to a preset pattern within the preset time period, the control current output to the voice coil motor also decreases synchronously, gradually weakening the control support force of the voice coil motor, allowing the lens carrier to move smoothly within a short period of time. Because the gain value is gradually reduced within a fixed, short period of time, the change in control current is more regular and controllable, avoiding sudden current changes caused by excessively long or short time periods. This further ensures smooth movement of the lens carrier and reduces the risk of impact. Furthermore, the preset time period makes the gain adjustment process more deterministic, enabling precise control of the time when the lens carrier reaches the natural position, improving overall control accuracy and ensuring that power-off operations are performed at the optimal time.

[0061] In some embodiments, Figure 4B As shown, in the embodiment of the present disclosure, gradually reducing the gain value from the current gain value to the target gain value may include the following steps: S404, obtaining parameter information of the camera module.

[0062] In this embodiment, the parameter information of the camera module may include the mass of the lens carrier and the lens, which directly determines the magnitude of the lens's descending inertia; the internal elastic coefficient of the voice coil motor, which reflects the deformation recovery force of the elastic element in the shrapnel voice coil motor; and the internal friction of the ball voice coil motor, which reflects the resistance encountered by the lens when moving. It may also include other parameters, which are not limited in this embodiment.

[0063] S406 , gradually reducing the gain value from the current gain value to the target gain value according to the parameter information of the camera module.

[0064] In this embodiment, the camera module's parameter information is associated with the gain reduction process. Based on this information, the gain is gradually reduced from its current value to a target value, thereby achieving smooth motor control and power-off. For example, if the lens is heavy due to its high inertia, the driver module will reduce the gain reduction rate to allow the control current to decay more slowly, preventing premature loss of support force and unstable lens hovering. For another example, if the elastic modulus of a shrapnel voice coil motor is high, the elastic recovery force can easily cause lens bounce. In this case, a stepwise gain reduction strategy is employed. After each stage of gain reduction, the gain is maintained for a predetermined period of stability. This phased maintenance of support force balances the elastic force until the gain reaches the target gain. For another example, if the internal friction of a ball-bearing voice coil motor is high, increasing the resistance to lens movement, the gain reduction rate may be increased initially to rapidly reduce the support force to overcome the resistance. Once the lens is within a predetermined distance (e.g., 0.1 mm) of its natural position, the gain reduction rate is further reduced to ensure the lens carrier reaches its natural position smoothly.

[0065] In this embodiment, through fine-grained adjustment based on the camera module parameter information, the change in gain value forms a dynamic match with the physical characteristics of the lens and motor, and ultimately the lens carrier reaches a natural position without impact, thereby reducing impact noise.

[0066] In some embodiments, there are multiple possible implementations of gradually reducing the gain value from the current gain value to the target gain value. Figure 5 As shown, in the embodiment of the present disclosure, gradually reducing the gain value from the current gain value to the target gain value may include the following steps: S502A: gradually reducing the gain value from the current gain value to the target gain value in a step-by-step manner.

[0067] In this embodiment, the gain reduction process is divided into N consecutive stages (N ≥ 2), with the gain value reduced to a preset fixed value at the end of each stage. It should be noted that the step sizes of the N consecutive stages can be uniform or non-uniform, for example, using larger step sizes in the early stages to accelerate attenuation and smaller step sizes in the later stages to maintain stability. It is understood that the number of stages N can also be dynamically adjusted based on the real-time needs of the driver module or environmental factors, such as a preset time period and / or camera module parameter information. The preset fixed value for each stage can be determined using a predefined algorithm or table lookup, ensuring a smooth and controllable gain reduction process. The step-by-step approach provided in this embodiment effectively avoids sudden gain changes. By gradually reducing the gain value, the control current of the voice coil motor is reduced, allowing the voice coil motor to gradually lose its control support force and smoothly reach its natural position.

[0068] S502B: gradually reduce the gain value from the current gain value to the target gain value based on a constant rate.

[0069] In this embodiment, the gain value is gradually reduced from the current gain value to the target gain value at a constant rate R. For example, the constant rate R is set based on a preset time period: R = (current gain value - target gain value) / preset time period. For another example, the constant rate R can be pre-set based on camera module parameter information. The constant rate R can also be set based on a preset time period and camera module parameter information, which is not limited in this embodiment.

[0070] S502C: gradually reducing the gain value from the current gain value to the target gain value based on a non-constant rate.

[0071] In this embodiment, to mitigate potential impact caused by inertia during the VCM's descent, a nonlinear gain reduction strategy is employed. Initially, the gain is reduced at a rapid rate, rapidly reducing the control current output to the VCM. This rapidly weakens the control support force on the VCM and accelerates the lens carrier's movement toward its natural position. Later, the gain is reduced at a gradual rate, gradually decreasing the control current and gently weakening the VCM's control support force, effectively mitigating the inertia of the lens carrier's descent. This nonlinear gain adjustment, which begins quickly and then slows down, allows the lens carrier to smoothly approach and reach its natural position.

[0072] In some embodiments, the gain value is gradually reduced from the current gain value to the target gain value based on a non-constant rate, which can specifically include: in the first stage of the movement of the lens carrier, the gain value is gradually reduced from the current gain value at a first rate; in the second stage of the movement of the lens carrier, the gain value is reduced at a second rate until the gain value reaches the target gain value, wherein the first rate is greater than the second rate. It should be noted that the nonlinear rate adjustment can be set according to a preset time period, or can be pre-set according to the parameter information of the camera module, or can be set according to the preset time period and the parameter information of the camera module, and this embodiment does not limit this. It should be noted that in actual applications, the method of gradually reducing the gain value from the current gain value to the target gain value based on a non-constant rate, in addition to the two-stage adjustment including the first stage and the second stage, can also be expanded to more stages of adjustment modes according to actual scene requirements, such as the third stage, the fourth stage, and even more stages.

[0073] In some embodiments, in this multi-stage adjustment mode, the rate of each preceding stage is greater than the rate of the succeeding stage. Specifically, in the third stage of lens carrier movement, the gain value is reduced at a third rate, with the second rate being greater than the third rate; if there is a fourth stage, the gain value is reduced at a fourth rate, with the third rate being greater than the fourth rate, and so on, until the gain value reaches the target gain value. It should be noted that due to the significant difference in the rate of each stage, the rate of change of the gain value will suddenly change at the moment of stage switching, thereby forming an inflection point of the broken line, that is, this multi-stage gain adjustment curve can be in the form of a non-smooth broken line.

[0074] In addition to the non-smooth broken-line adjustment curves described above, there may also be smooth arc-shaped gain adjustment curves. For example, the gain value can be adjusted based on a sine curve or cosine curve. In this case, the non-constant rate decreases in real time over time. Taking the sine curve as an example, assuming that the gain adjustment curve follows the decay form of a sine function, the rates of the multiple stages are the derivatives of the sine function at a certain moment, and their values ​​gradually decrease over time, making the gain value change from the current value to the target value present a smooth arc shape, avoiding the adverse effects of sudden rate changes.

[0075] It should be noted that the specific parameters of the above-mentioned multi-stage broken line adjustment and smooth arc adjustment, such as the rate and duration of each stage, the specific parameters of the sine or cosine curve, etc., can be set according to a preset time period, or can be pre-set according to the parameter information of the camera module, or can be set together according to the preset time period and the parameter information of the camera module. This embodiment does not impose any restrictions on this.

[0076] In some embodiments, gradually reducing the gain value from the current gain value to the target gain value based on a non-constant rate includes: during at least one phase of the movement of the lens carrier, the non-constant rate decreases in real time over time.

[0077] In this embodiment, the overall movement time is shortened and the dynamic response efficiency of the drive module is improved through rapid adjustment in the early stage, and the positioning accuracy is ensured by smooth adjustment in the later stage, thus achieving a balance between efficiency and accuracy.

[0078] In some embodiments, in order to ensure the stability and anti-interference capability in the closed-loop control, the stability and anti-interference capability in the closed-loop control are measured by the phase margin. Figure 6The diagram of the relationship curve between frequency and gain value is shown, where the horizontal axis represents frequency F, one vertical axis represents gain (unit: dB), and the other represents phase θ (unit: degree); the gain line S1 shows how the gain of the open-loop system changes with frequency, and the phase line S2 shows how the phase changes with frequency. The phase margin is defined as the phase margin of the system at the intersection of the -180° phase line S2 and the open-loop transfer function at the crossing frequency of the gain line S1 (that is, the frequency when the gain of the open-loop transfer function is equal to 1 or 0dB). It should be noted that for the lower frequency part, the phase margin needs to be large enough to ensure that the driving module will not be unstable or oscillate due to phase lag in the low frequency band. Therefore, in order to ensure the stability of the driving module, the determination of the gain value in this embodiment is also subject to the constraints of the phase margin. Combined with Figure 6 Shown and Figure 7 As shown, in the embodiment of the present disclosure, gradually reducing the gain value from the current gain value to the target gain value may include the following steps: S702 : Under the phase margin constraint, gradually reduce the gain value from the current gain value to the target gain value.

[0079] In this embodiment, the driving module monitors the phase margin at different frequencies in real time during the process of reducing the gain value. In the low frequency band, the phase margin is ensured to be maintained at a sufficiently large value to avoid instability or oscillation caused by insufficient phase margin due to a rapid decrease in the gain value; in other frequency bands, the phase margin is always kept within a reasonable range to ensure the stability and anti-interference ability of the closed-loop control. In this way, the gain value is gradually reduced from the current value to the target value, so that the lens carrier can be smoothly moved to the natural position. It should be noted that in the embodiment of the present disclosure, the target gain value can also be constrained by the phase margin.

[0080] In this embodiment, the gain value is reduced under the phase margin constraint, making the gain value adjustment more reasonable, avoiding the control risk caused by blindly reducing the gain value, and improving the reliability of the lens carrier movement control.

[0081] Based on the same public concept, see Figure 8 As shown, the embodiment of the present disclosure further provides a camera module 80, including a lens 2 and the voice coil motor control device 1 described in any of the above embodiments.

[0082] Based on the same public concept, see Figure 9 As shown, an embodiment of the present disclosure further provides an electronic device 90, which includes: a processor 91; and a memory 92 for storing executable instructions of the processor; wherein the processor 91 is configured to execute the voice coil motor control method described in any of the above embodiments by executing the executable instructions.

[0083] It should be noted that the examples and application scenarios implemented by the modules in the above-mentioned apparatus embodiment are the same as those implemented by the corresponding steps in the method embodiment, but are not limited to the contents disclosed in the above-mentioned method embodiment. It should be noted that the above-mentioned modules, as part of the apparatus, can be executed in a computer system, such as a set of computer-executable instructions.

[0084] Those skilled in the art will appreciate that various aspects of the present disclosure may be implemented in the following forms, namely: a complete hardware implementation, a complete software implementation (including firmware, microcode, etc.), or an implementation that combines hardware and software aspects, which may be collectively referred to herein as a "circuit," "module," or "system."

[0085] Based on the same disclosed concept, embodiments of the present disclosure also provide a computer-readable storage medium storing a computer program that, when executed by a processor, implements any of the aforementioned voice coil motor control methods. Because the principles underlying the problems solved by this computer-readable storage medium embodiment are similar to those of the aforementioned method embodiment, the implementation of this computer-readable storage medium embodiment can be referenced to the implementation of the aforementioned method embodiment, and any repetitive details will not be repeated.

[0086] More specific examples of computer-readable storage media in the present disclosure may include, but are not limited to, an electrical connection having one or more conductors, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), optical fibers, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0087] In the present disclosure, a computer-readable storage medium may include a data signal propagated in baseband or as part of a carrier wave, which carries readable program code. Such propagated data signals may take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A readable signal medium may also be any readable medium other than a readable storage medium that can transmit, propagate, or transfer a program for use by or in conjunction with an instruction execution system, apparatus, or device.

[0088] Alternatively, the program code contained on the computer-readable storage medium may be transmitted using any appropriate medium, including but not limited to wireless, wired, optical cable, RF, etc., or any suitable combination thereof.

[0089] In a specific implementation, the program code for performing the operations of the present disclosure may be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java, C++, and conventional procedural programming languages ​​such as C or similar programming languages. The program code may be executed entirely on the user's computing device, partially on the user's device, as a standalone software package, partially on the user's computing device and partially on a remote computing device, or entirely on a remote computing device or server. In the case of a remote computing device, the remote computing device may be connected to the user's computing device via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0090] Based on the same disclosed concept, embodiments of the present disclosure further provide a computer program product, including a computer program or instructions. When executed by a processor, the computer program or instructions implement the voice coil motor control method according to any of the aforementioned method embodiments. Because the principles underlying the problems solved by this computer program product embodiment are similar to those of the aforementioned method embodiments, the implementation of this computer program product embodiment can be referenced to the implementation of the aforementioned method embodiments, and any repetitive details will not be repeated.

[0091] It should be noted that although several modules or units of the device for action execution are mentioned in the detailed description above, this division is not mandatory. In fact, according to the embodiments of the present disclosure, the features and functions of two or more modules or units described above can be concretized in one module or unit. Conversely, the features and functions of one module or unit described above can be further divided into multiple modules or units to be concretized.

[0092] Furthermore, although the steps of the method of the present disclosure are described in a particular order in the accompanying drawings, this does not require or imply that the steps must be performed in this particular order, or that all steps shown must be performed to achieve the desired results. Additionally or alternatively, some steps may be omitted, multiple steps may be combined into one step, and / or one step may be decomposed into multiple steps.

[0093] Through the description of the above embodiments, it will be readily understood by those skilled in the art that the example embodiments described herein can be implemented via software or via a combination of software and necessary hardware. Therefore, the technical solutions according to the embodiments of the present disclosure can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (such as a CD-ROM, USB flash drive, or mobile hard drive) or on a network and includes several instructions for enabling a computing device (such as a personal computer, server, mobile terminal, or network device) to execute the methods according to the embodiments of the present disclosure.

[0094] Other embodiments of the present disclosure will readily occur to those skilled in the art after considering the specification and practicing the disclosure herein. This disclosure is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, with the true scope and spirit of the present disclosure being indicated by the appended claims.

Claims

1. A voice coil motor control method, characterized in that: include: In response to a power indication signal from the camera module, obtaining a current gain value and a target gain value of the voice coil motor, wherein the target gain value corresponds to a target position of a lens carrier in the voice coil motor; During the movement of the lens carrier toward the target position, gradually reducing the gain value from the current gain value to the target gain value; A driving signal is generated based on the reduced gain value to control the lens carrier to move to the target position.

2. The voice coil motor control method according to claim 1, wherein: The step of gradually reducing the gain value from the current gain value to the target gain value includes: The gain value is gradually reduced from the current gain value to the target gain value within a preset time period.

3. The voice coil motor control method according to claim 1 or 2, characterized in that: The step of gradually reducing the gain value from the current gain value to the target gain value includes: reducing the gain value from the current gain value to the target gain value in a step-by-step manner; or reducing the gain value from the current gain value to the target gain value step by step based on a constant rate; or The gain value is gradually reduced from the current gain value to the target gain value based on a non-constant rate.

4. The voice coil motor control method according to claim 3, wherein: The step of gradually reducing the gain value from the current gain value to the target gain value based on a non-constant rate includes: In a first phase of movement of the lens carrier, gradually reducing the gain value from the current gain value at a first rate; During a second phase of movement of the lens carrier, the gain value is reduced at a second rate until the gain value reaches the target gain value, wherein the first rate is greater than the second rate.

5. The voice coil motor control method according to claim 3, wherein: The step of gradually reducing the gain value from the current gain value to the target gain value based on a non-constant rate includes: During at least one phase of the movement of the lens carrier, the non-constant rate decreases in real time over time.

6. The voice coil motor control method according to claim 1 or 2, characterized in that: The method further comprises: Obtaining parameter information of the camera module; The gain value is gradually reduced from the current gain value to the target gain value according to the parameter information of the camera module.

7. The voice coil motor control method according to claim 1, wherein: The step of gradually reducing the gain value from the current gain value to the target gain value includes: Under the phase margin constraint, the gain value is gradually reduced from the current gain value to the target gain value.

8. The voice coil motor control method according to claim 1, wherein: After generating a driving signal based on the reduced gain value to control the lens carrier to move to the target position, the method further includes: Cut off the power supply of the camera module.

9. The voice coil motor control method according to claim 1, wherein: The power indication signal is obtained in at least one of the following ways: receiving a power-off instruction of the camera module from a control module; or receiving a power-off signal of the camera module from a control module; or Detecting the power status of the camera module.

10. A voice coil motor control device, characterized in that: include: a driving module configured to obtain a current gain value and a target gain value of the voice coil motor in response to a power indication signal from the camera module, wherein the target gain value corresponds to a target position of a lens carrier in the voice coil motor; During the movement of the lens carrier toward the target position, gradually reducing the gain value from the current gain value to the target gain value; A driving signal is generated based on the reduced gain value to control the lens carrier to move to the target position.

11. The voice coil motor control device according to claim 10, wherein: Also includes: a control module configured to send a power-off instruction of the camera module to the driving module; or, Outputting a power-off signal of the camera module to the driving module.

12. The voice coil motor control device according to claim 10, wherein: The driving module includes a peripheral circuit; The peripheral circuit is configured to set the current gain value and a target gain value.

13. The voice coil motor control device according to claim 12, wherein: The driving module includes a gain module, and the gain module has a built-in control circuit; The control circuit built into the gain module is configured to set the current gain value and the target gain value.

14. A camera module, characterized in that: The invention comprises a lens and a voice coil motor control device as described in any one of claims 10 to 13.

15. An electronic device, characterized in that: include: processor; a memory for storing instructions executable by the processor; The processor is configured to execute the instructions to implement the voice coil motor control method according to any one of claims 1 to 9.

16. A computer-readable storage medium having instructions stored thereon, characterized in that: When the instructions in the computer-readable storage medium are executed by a processor of an electronic device, the electronic device is enabled to execute the voice coil motor control method according to any one of claims 1 to 9.

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