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

Abstract

The present disclosure provides a voice coil motor control method and device, a camera module and an electronic device, and is applied to the technical field of camera shooting. The method comprises the following steps: in response to a power indication signal of a camera module, obtaining a current gain value and a target gain value of a voice coil motor, 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 in the process that the lens carrier moves to the target position; generating a driving signal based on the reduced gain value, and controlling the lens carrier to move to the target position. The embodiment of the present disclosure can simply and efficiently reset the lens to the target position, so as to reduce the impact and also reduce the impact noise.

Description

Technical Field

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

[0002] With the widespread use of electronic devices (such as smartphones, tablets, and laptops), camera modules integrated into these devices have become standard components. The voice coil motor (VCM), as the core driving component of the camera module, controls the movement of the lens and lens carrier along the optical axis through electromagnetic force, thereby achieving focusing and optical image stabilization.

[0003] The moment the camera module is powered off, the electromagnetic support force of the voice coil motor disappears instantly, causing the lens carrier to move uncontrollably under the inherent forces of the mechanical structure. Specifically, in a ball-bearing VCM structure, the lens carrier falls freely due to gravity; in a spring-loaded VCM structure, the carrier rebounds rapidly under the restoring force of the spring. This movement causes the lens carrier to impact the voice coil motor housing, resulting in a mechanical impact. Furthermore, because the impact point is near the device's microphone, this noise is easily picked up and amplified, significantly impacting the user experience.

[0004] To suppress impact noise, related technical solutions rely on the accelerometer in the gyroscope to provide gravitational acceleration signals. The lens's natural position in a static environment is then calculated using the gravitational acceleration vector. The lens carrier is then moved to that position before a power-off operation is performed, shortening the impact travel distance and reducing impact noise. However, this solution requires calculating the gravity direction using the gravity signal from the gyroscope to determine the lens's trajectory and target position, resulting in high algorithm complexity. Furthermore, if the electronic device shakes, dynamic changes in the gravity direction can easily lead to system misjudgments, causing the actual effect to deviate from expectations.

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

[0006] This disclosure provides a voice coil motor control method, device, camera module, and electronic device that does not require acquiring the gravitational acceleration signal from the gyroscope or performing complex calculations on the target position using the gravitational acceleration signal. It also effectively avoids misjudgment of the target position due to changes in the direction of gravity, and can simply and efficiently and smoothly reset the lens to the target position to reduce impact noise.

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

[0008] According to one aspect of this disclosure, a voice coil motor control method is provided, comprising: in response to a power indication signal of a camera module, acquiring 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; and generating a drive signal based on the reduced gain value to control the lens carrier to move 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, the step of 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 in a stepwise manner; or, gradually reducing the gain value from the current gain value to the target gain value at a constant rate; or, gradually reducing the gain value from the current gain value to the target gain value at a non-constant rate.

[0011] In some embodiments, 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 lens carrier movement, reducing the gain value gradually from the current gain value at a first rate; and in a second phase of lens carrier movement, 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, 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 lens carrier movement, 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 based on the parameter information of the camera module.

[0014] In some embodiments, the step of 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 phase margin constraints.

[0015] In some embodiments, after generating a drive 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 to the camera module.

[0016] In some embodiments, the power indication signal is acquired by at least one of the following methods: receiving a power-down indication from the control module for the camera module; or receiving a power-off signal from the control module for the camera module; or detecting the power status of the camera module.

[0017] According to another aspect of this disclosure, a voice coil motor control device is also provided, comprising: a drive module configured to, in response to a power indication signal of a camera module, acquire 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 reduce the gain value from the current gain value to the target gain value; 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-down instruction for the camera module to the drive module; or to output a power-off signal for the camera module to the drive module.

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

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

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

[0022] According to another aspect of this disclosure, an electronic device is also provided, comprising: a processor; and a memory for storing executable instructions of the processor; wherein the processor is configured to perform the voice coil motor control method described in any of the preceding claims by executing the executable instructions.

[0023] According to another aspect of this disclosure, a computer program product is also provided, comprising: a computer program or instructions that, when executed by a processor, implement the voice coil motor control method of any one of the above.

[0024] This disclosure provides a voice coil motor control method, apparatus, camera module, and electronic device. The method includes: responding to a power indication signal from the camera module, acquiring 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 the lens carrier within the voice coil motor; during the movement of the lens carrier towards the target position, gradually reducing the gain value from the current gain value to the target gain value; and generating a drive signal based on the reduced gain value to control the lens carrier to move to the target position. This disclosure generates a drive signal by dynamically adjusting the gain value to control the lens carrier to move to the target position. It eliminates the need to acquire the gravitational acceleration signal from the gyroscope and avoids complex calculations of the target position using the gravitational acceleration signal. It also effectively avoids misjudgment of the target position due to changes in the direction of gravity, enabling simple and efficient smooth repositioning of the lens to the target position, reducing impact and noise.

[0025] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0026] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0027] Figure 1A This diagram shows one of the schematic diagrams of a voice coil motor control device according to an embodiment of the present disclosure; Figure 1B This is a second schematic diagram of a voice coil motor control device according to an embodiment of the present disclosure; Figure 1C This is shown as a third schematic diagram of a voice coil motor control device according to an embodiment of the present disclosure; Figure 1D This is shown as a fourth schematic diagram of a voice coil motor control device according to an embodiment of the present disclosure; Figure 2 This diagram illustrates a method flowchart of a voice coil motor control method according to an embodiment of the present disclosure; Figure 3 This diagram illustrates a voice coil motor assembly architecture according to an embodiment of the present disclosure. Figure 4A This illustration shows one of the flowcharts of a method for gradually reducing a gain value from a current gain value to a target gain value according to an embodiment of this disclosure; Figure 4BThis is a second flowchart illustrating a method for gradually reducing a gain value from a current gain value to a target gain value according to an embodiment of this disclosure; Figure 5 This is the third flowchart of a method for gradually reducing a gain value from a current gain value to a target gain value according to an embodiment of the present disclosure; Figure 6 This diagram illustrates a frequency versus gain curve in an embodiment of the present disclosure. Figure 7 This is shown as the fourth flowchart of a method for gradually reducing a gain value from a current gain value to a target gain value according to an embodiment of the present disclosure; Figure 8 This diagram illustrates a camera module according to an embodiment of the present disclosure; Figure 9 A schematic diagram of an electronic device according to an embodiment of the present disclosure is shown. Detailed Implementation

[0028] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, they are provided so that this disclosure will be more comprehensive and complete, and will fully convey the concept of the exemplary 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 this disclosure can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this disclosure. However, those skilled in the art will recognize that the technical solutions of this disclosure can be practiced with one or more specific details omitted, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this disclosure.

[0030] Furthermore, the accompanying drawings are merely illustrative of this disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and therefore repeated descriptions of them will be omitted. Some block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0031] The flowchart shown in the accompanying drawings is merely illustrative and does not necessarily include all content and steps, nor does it require execution in the described order. For example, some steps may be broken down, while others may be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0032] In this specification, the terms “a,” “an,” “the,” “the,” 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 indicate an open-ended inclusion and to mean that there may be other elements / components / etc. in addition to the listed elements / components / etc.; the terms “first,” “second,” and “third,” etc., are used only as markings and are not a limitation on the number of objects.

[0033] The specific implementation methods of the embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.

[0034] like Figure 1A The diagram shown is a schematic representation of a voice coil motor control device provided in an embodiment of this disclosure. Figure 1A As shown, this disclosure provides a voice coil motor control device 1 including a drive module 10, which controls the voice coil motor 20 to drive the lens carrier of a camera module to move and smoothly reset the lens carrier to a target position. This voice coil motor control device can be applied to electronic devices with camera modules, such as mobile phones, laptops, and tablets. The camera module may include a voice coil motor frame and a lens carrier, which is used to fix and support the lens. The voice coil motor drive module 10 is mainly electrically connected to the voice coil motor of the camera module of the electronic device. It controls the movement of the lens carrier of the camera module accordingly by acquiring the current gain value and the target gain value of the voice coil motor. It should be noted that the drive module 10 can be a separate drive chip, separately from the voice coil motor 20. Alternatively, the drive module 10 can be coupled to the voice coil motor 20. Specifically, the drive module is configured to respond to the power indication signal of the camera module, acquire the current gain value and the target gain value of the voice coil motor, 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 towards the target position, the gain value is gradually reduced from the current gain value to the target gain value; and a drive signal is generated based on the reduced gain value to control the lens carrier to move to the target position.

[0035] See Figure 1BAs shown, the driving module 10 provided in this embodiment 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. The first end of the analog-to-digital converter 11 is connected to the first end of the voice coil motor 20, and the other end of the analog-to-digital converter 11 is connected to the first end of the PID controller 12. The first end of the PID controller 12 is connected to the first end of the gain module 13. The second end of the gain module 13 is connected to the first end of the digital-to-analog converter 14, and the second end of the digital-to-analog converter 14 is connected to the first end of the driving unit 15. The second end of the driving unit 15 is connected to the second end of the voice coil motor 20. In response to the power indication signal of the camera module, the gain value of the gain module 13 gradually decreases from the current gain value to the 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 and outputs it to the driving unit 15. The driving unit 15 then generates a driving current applied to the voice coil motor based on the received analog signal, causing the voice coil motor to drive the lens carrier to move to the target position. Here, the driving unit 15 can be a driving circuit or a chip. When the driving unit 15 is a driving circuit, the driving circuit can specifically be an H-bridge circuit.

[0036] It should be noted that the gain value setting is automatic. The target gain value can be set to zero or a near-zero minimum value, such as ±5dB or ±1dB; or the target position can correspond to the required gain value. In some embodiments, the drive module 10 includes peripheral circuitry; the peripheral circuitry 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 control circuitry built into the gain module 13 is configured to set the current gain value and the target gain value, for example, by controlling the gain value setting through a program pre-programmed into the gain module 13 circuitry.

[0037] In some embodiments, see Figure 1C As shown, the drive module 10 provided in this embodiment further includes a setpoint setting unit 16, used to set the parameter values ​​of the voice coil motor, for example, setting the target position of the lens carrier in a scenario where servo-controlled descent is disabled. It should be noted that in this embodiment, the hardware configuration of the setpoint input unit does not need to be changed; it supports input value setting, which is set via the IIC interface through the user platform. It should also be noted that since this embodiment achieves the descent of the lens carrier by automatically adjusting the gain value of the gain module 13, it does not require position feedback from the analog-to-digital converter 11, nor does it require modulation by the PID controller 12 and the setpoint setting unit 16.

[0038] In some embodiments, see Figure 1DAs shown, the drive module 10 provided in this embodiment further includes a target value setting unit 17, used to set the parameter value of the voice coil motor when the servo is enabled, ensuring that the voice coil motor smoothly supports lens zoom. It can be understood that when the 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 processes, the gain module 13 can directly call this current gain value to drive the lens carrier to achieve a smooth descent, without needing to additionally obtain the position information of the lens carrier.

[0039] In some embodiments, the output value of the digital-to-analog converter 14 can also be temporarily stored in a register for use by the drive unit 15 circuit to adjust the drive current applied to the voice coil motor, thereby causing 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 drive module 10. The control module 30 is configured to send a power-down instruction for the camera module to the drive module 10, or to output a power-off signal for the camera module to the drive module 10. It should be noted that the control module 30 can be configured independently, for example, as the control chip for the camera module or the control chip for the electronic device, or it can be integrated with the drive module 10 into the same drive chip. Furthermore, 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 chips for various peripheral sensors of the electronic device, or the control chip for the display screen.

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

[0042] In this embodiment, the power indication signal of the camera module is used to trigger the voice coil motor drive module to cut off the power supply. Specifically, the power indication signal may contain a signal containing specific power state change information. Its function is to drive the system to power off or transition to a low power state by transmitting relevant instructions, ultimately leading to a power-off result. In the camera module scenario, when this signal triggers a power-off, the electromagnetic support force of the voice coil motor will immediately disappear, and the lens carrier is easily driven by the inherent forces of the mechanical structure to undergo uncontrolled movement.

[0043] In some embodiments, the power indication signal may include a power-off signal or a power-down indication. That is, the power indication signal is directly related to the power-off process of the voice coil motor and is the key signal that triggers the power-off of the voice coil motor. A power-off signal is a signal issued by the system to directly initiate the power-off process when the device receives a camera module shutdown operation command, causing the hardware of the camera module, including the voice coil motor, to stop operating and cut off the power supply. A power-down indication is a predictive power-off signal. For example, when the system responds to a user's operation command, it issues an indication that it will perform a power-off within a short time, allowing time for the drive module to complete a smooth descent, ultimately still aiming to trigger a power-off.

[0044] In some embodiments, the power indication signal may also include a signal or indication of switching from high power to low power. This type of signal serves as a pre-triggered signal for power failure, preparing for a subsequent power outage and working in conjunction with a dynamic gain adjustment mechanism to ensure lens reset. When the camera module is operating at high power, the system sends this signal and then uses dynamic gain adjustment to generate a drive signal to control lens reset.

[0045] Reference Figure 3 The diagram shows a schematic of a voice coil motor assembly. 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 bearing voice coil motor) or spring force (spring spring voice coil motor), it falls freely or rebounds rapidly to impact its mechanical limit. Figure 3 Impact noise is generated on the frame 22. The target position, also called the natural position, refers to the final static equilibrium point reached by the lens carrier under passive physical forces such as gravity and spring force when it is completely free from electromagnetic forces. In addition, the target position can also refer to the stable position that the lens carrier automatically returns to after the system is powered off, that is, the power-off zero point 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 and started, that is, the power-on initial position, can also be regarded as a default target position reference point, and this disclosure does not limit it.

[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 or the spring preload equilibrium point of the spring voice coil motor. The target position can be the final static equilibrium point or a position infinitely close to the final static equilibrium point. When the lens carrier is at the target position, the lens carrier 21 will not hit its mechanical limit and generate noise even if it loses electromagnetic force support. Or, even if it loses electromagnetic force support, the impact noise can be reduced as the distance from the target position to the mechanical limit is shortened. The specific target position value is not limited in the embodiments disclosed herein.

[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 supporting 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, that is, the gain value of the static equilibrium point reached by the lens carrier under the action of passive mechanical forces such as gravity and spring preload, without the action of electromagnetic force, or a position infinitely close to the final static equilibrium point.

[0048] It should be noted that the gain module in this embodiment is not a new component; the system still requires the gain module even without a power-off operation. The main function of the gain module 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 of the camera module. Therefore, this embodiment can obtain the current gain value of the voice coil motor in real time. In addition, since the target position is determined by the mechanical structure of the voice coil motor and is usually fixed, the target gain value can be preset.

[0049] In some embodiments, the power indication signal can be acquired in several ways. In some embodiments, acquiring the power indication signal may include receiving a power-down instruction from the control module's camera module. This means the drive module receives a command from the control module that explicitly instructs the camera module to perform a power-down operation. This command is typically a control command with a specific format and content. Upon receiving it, the drive module will initiate the corresponding power-down process. It should be noted that this power-down instruction can be actively triggered by the user through the operating interface. This embodiment can respond to the user's control intentions, reduce erroneous operations, ensure the power-down process starts orderly according to a preset procedure, and improve power reliability.

[0050] In some embodiments, acquiring the power indication signal may include receiving a power-off signal from the camera module of the control module. Specifically, the drive module acquires an electrical signal transmitted by the control module to trigger a power-off of the camera module. This signal may be a specific voltage signal, current signal, etc., and the power-off indication is transmitted through changes in the electrical signal. In this embodiment, using an electrical signal to transmit the power-off indication results in a fast response time, enabling the power-off operation to be triggered within a short period.

[0051] In some embodiments, acquiring the power indication signal may include detecting the power status of the camera module. That is, the drive 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 within the camera module. Based on the real-time monitoring results, the drive module accurately identifies specific power status change events, which trigger subsequent lens reset control procedures as power indication signals. The power status may include a power-off control status: directly indicating that the system is about to or is performing a power-off operation. The power status may also include a power mode switching status: indicating that the system is switching between different power modes (such as high power mode and low power mode). In this embodiment, the drive module determines the power-off status by actively monitoring the power status, enabling it to grasp the power-off needs of the camera module in real time without relying on active transmission from an external control module. This enhances the system's autonomy and independence, allows it to respond to power-off needs when the control module malfunctions, and improves the overall system stability.

[0052] In some embodiments, an intermediate waiting state or idle state can be introduced during the switching from a high-power mode to a low-power mode to ensure the smoothness and reliability of the control process. Specifically, when the drive module detects a need to enter low-power operation (such as device standby or image acquisition completion), it first switches the camera module from the high-power operation state to the intermediate waiting state or idle state. In this state, the core functions of the camera module are suspended, but basic power supply and communication capabilities are maintained. Instead, it waits for and receives necessary low-power mode configuration signals or parameters, thus triggering the subsequent lens reset control process. By introducing an intermediate waiting state or idle state during the power switching process, this embodiment can complete the necessary parameter configuration and status confirmation before performing the lens reset operation, thereby ensuring that the generation of drive signals and power management strategies are synchronized and coordinated. This method not only achieves efficient and smooth control of lens movement and effectively reduces mechanical impacts during movement, but also reduces structural vibration and noise caused by abrupt movements, improving user experience and system reliability.

[0053] S204, as the lens carrier moves toward the target position, the gain value is gradually reduced from the current gain value to the target gain value.

[0054] In this embodiment, during the movement of the lens carrier towards the target position (natural position), the drive module presets a current gain value and a target gain value, and the change characteristics of this gain value are independent of the real-time position of the lens carrier. After the movement is initiated, the drive module gradually reduces the gain value from the current gain value to the target gain value according to a preset fixed gradient or time interval. As the gain value gradually decreases, the control current output to the voice coil motor decreases synchronously, causing the control support force on the voice coil motor to gradually weaken. The lens carrier falls smoothly during this process, and when the gain value reaches the target gain value, the lens carrier arrives at the natural position smoothly.

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

[0056] In this embodiment, the driving signal can specifically be a driving current. The driving current decreases synchronously with the decrease in gain value to ensure smooth movement of the lens carrier. When the gain value reaches the target gain value, the driving current approaches zero or reaches zero, at which point the lens is stably docked at the target position.

[0057] In some embodiments, after generating a drive 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 to the camera module. In this embodiment, the target position is the natural position. After generating the drive signal based on the reduced gain value and controlling the lens carrier to move to the natural position, in response to the gain value dropping to the target value and / or the drive current approaching zero, a power-down indication is generated, triggering the power management unit to cut off the power supply circuit of the camera module, thereby powering down the drive module and the voice coil motor together. Since the lens carrier has already moved to the natural position, powering down at this time can reduce the noise generated by the impact between the lens carrier and the mechanical limiter.

[0058] In this embodiment, there is no need for complex natural position calculations using accelerometer signals from the gyroscope assembly. Instead, the output current of the voice coil motor is reduced by decreasing the gain value, thereby gradually weakening the supporting force on the lens carrier and allowing the lens to smoothly return to its natural position. This reduces impact and noise, making it simple, effective, and low-cost. Furthermore, since this embodiment does not require complex natural position calculations using accelerometer signals from the gyroscope assembly, it also overcomes 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 this embodiment of the disclosure, gradually reducing the gain value from the current gain value to the target gain value may include the following steps: S402, within a preset time period, gradually reduce the gain value from the current gain value to the target gain value.

[0060] In this embodiment, when the lens carrier moves towards the target position (natural position), the drive module can set a preset time period. This preset time period is understood to be relatively short, such as 100ms, and within this period, 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 related to the preset time. 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 in a short time. Because the gain value gradually decreases within a fixed short time, the change in control current is more regular and controllable, avoiding sudden current changes caused by excessively long or short time periods, further ensuring the smoothness of the lens carrier's movement and reducing the risk of impact. Furthermore, the preset time period makes the gain adjustment process more deterministic, accurately controlling the time it takes for the lens carrier to reach the natural position, improving the overall control accuracy, and ensuring that the power-down operation is performed at the optimal time.

[0061] In some embodiments, Figure 4B As shown, in this embodiment of the disclosure, gradually reducing the gain value from the current gain value to the target gain value may include the following steps: S404, obtain 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 descent inertia; the internal elastic coefficient of the voice coil motor, which reflects the deformation recovery force of the elastic element in the spring-type voice coil motor; and the internal friction force of the ball-bearing voice coil motor, which reflects the resistance encountered when the lens moves. Other parameters may also be included, but this embodiment does not limit them.

[0063] S406, based on the parameter information of the camera module, gradually reduces the gain value from the current gain value to the target gain value.

[0064] In this embodiment, the parameter information of the camera module is related to the process of reducing the gain value. Based on the parameter information of the camera module, the gain value is gradually reduced from the current value to the target value, thereby achieving smooth control and power-down of the motor. For example, if the lens mass is large, due to its large inertia, the drive module will reduce the rate of gain reduction to slowly decay the control current, avoiding premature loss of support force and resulting in unstable lens hovering. Another example is when the internal elastic coefficient of the spring-type voice coil motor is high, the elastic restoring force can easily cause the lens to bounce. In this case, a step-wise reduction strategy is adopted for the gain value. After each stage of gain reduction, a preset stabilization period is maintained to maintain the support force and balance the elastic force until the gain value drops to the target gain value. Yet another example is when the internal friction of the ball-type voice coil motor is large, increasing the resistance to lens movement. Initially, the rate of gain reduction needs to be increased to quickly weaken the support force to overcome the resistance. When the lens descends to within a preset distance (e.g., 0.1 mm) from its natural position, the rate of gain reduction is then reduced to ensure that the lens carrier eventually reaches its natural position smoothly.

[0065] In this embodiment, through fine-tuning based on camera module parameter information, the change in gain value is dynamically matched with the physical characteristics of the lens and motor, ultimately enabling the lens carrier to reach its natural position without impact, thereby reducing impact noise.

[0066] In some embodiments, there are several possible ways to gradually reduce the gain value from the current gain value to the target gain value. Figure 5 As shown, in this embodiment of the disclosure, gradually reducing the gain value from the current gain value to the target gain value may include the following steps: The S502A is based on a step-by-step approach that gradually reduces the gain value from the current gain value to the target gain value.

[0067] In this embodiment, the gain attenuation process is divided into N consecutive stages (N≥2), and the gain value is reduced to a preset fixed value at the end of each stage. It should be noted that the step size of the N consecutive stages can be uniform or non-uniform; for example, a larger step size can be used in the early stages to accelerate attenuation, while a smaller step size can be used 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 requirements of the drive module or environmental factors, such as a preset time period and / or the parameter information of the camera module. The preset fixed value for each stage can be determined through a predefined algorithm or a lookup table to ensure that the gain reduction process is smooth and controllable. The step-by-step method provided in this embodiment effectively avoids abrupt gain changes. By gradually reducing the gain value, the control current to the voice coil motor is reduced, allowing the voice coil motor to gradually lose control support and smoothly reach its natural position.

[0068] The S502B gradually reduces 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 according to a preset time period: R = (current gain value - target gain value) / preset time period. Alternatively, the constant rate R can be preset based on the camera module's parameter information. The constant rate R can also be set based on a preset time period and the camera module's parameter information; this embodiment does not impose any limitations on this.

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

[0071] In this embodiment, to eliminate potential impacts caused by inertia during the descent of the voice coil motor, a non-linear processing strategy is employed to reduce the gain value: In the initial stage of reduction, the gain value is decreased at a relatively fast rate, rapidly reducing the control current output to the voice coil motor and quickly weakening the control support force on the motor, thus accelerating the movement of the lens carrier towards its natural position; in the later stage of reduction, the gain value is reduced at a gradual rate, and the control current decreases slowly accordingly, gently weakening the control support force of the voice coil motor and effectively buffering the inertia of the lens carrier's descent. Through this non-linear gain adjustment that is fast at first and then slow, the lens carrier can 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. Specifically, this may include: in a first stage of lens carrier movement, reducing the gain value gradually from the current gain value at a first rate; and in a second stage of lens carrier movement, 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. It should be noted that the non-linear rate adjustment can be set according to a preset time period, or it can be preset based on the parameter information of the camera module, or it can be set based on both the preset time period and the parameter information of the camera module. This embodiment does not impose any limitations on this. It should also be noted that in practical 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 and second stages, can be extended to more stages of adjustment, such as a third stage, a fourth stage, or even more stages, depending on the actual scenario requirements.

[0073] In some embodiments, in this multi-stage adjustment mode, the rate of each preceding stage is greater than the rate of the following stage. Specifically, in the third stage of lens carrier movement, the gain value is reduced at a third rate, and the second rate is greater than the third rate; if a fourth stage exists, the gain value is reduced at a fourth rate, and the third rate is 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 rate between each stage, the rate of change of the gain value will change abruptly at the moment of stage switching, thus forming the inflection point of the broken line, that is, the gain adjustment curve of this multi-stage mode can be a non-smooth broken line.

[0074] In addition to the non-smooth, linear adjustment curves mentioned above, there may also be smooth, curved gain adjustment curves. For example, the gain value can be adjusted based on a sine or cosine curve. In this case, the non-constant rate decreases in real time. Taking a sine curve as an example, assuming the gain adjustment curve follows the decay form of a sine function, the rate at multiple stages is the derivative of this sine function at a certain moment. Its value gradually decreases over time, making the change in gain value from the current value to the target value present a smooth, curved 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 speed and duration of each stage, and the specific parameters of the sine or cosine curve, can be set according to the preset time period, or can be preset 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 limit 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: the non-constant rate decreasing in real time over time during at least one phase of the lens carrier movement.

[0077] In this embodiment, the overall movement time is shortened by rapid adjustment in the early stage, which improves the dynamic response efficiency of the drive module, 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, to ensure stability and anti-interference capability in closed-loop control, phase margin is used to measure the stability and anti-interference capability of closed-loop control. (Refer to...) Figure 6The diagram illustrates the relationship between frequency and gain. The horizontal axis represents frequency F, and the vertical axes represent gain (in dB) and phase θ (in degrees). Gain line S1 shows the change of open-loop system gain with frequency, while phase line S2 shows the change of phase with frequency. Phase margin is defined as the phase margin at the intersection of the -180° phase line S2 and the phase of the open-loop transfer function at the frequency where gain line S1 crosses (i.e., the frequency at which the gain of the open-loop transfer function equals 1 or 0 dB). It should be noted that for the lower frequency range, the phase margin needs to be sufficiently large to ensure that the drive module does not become unstable or oscillate due to phase lag in the low-frequency range. Therefore, to ensure the stability of the drive module, the determination of the gain value in this embodiment is also constrained by the phase margin. Figure 6 As shown and Figure 7 As shown, in this embodiment of the disclosure, gradually reducing the gain value from the current gain value to the target gain value may include the following steps: S702, under phase margin constraints, gradually reduces the gain value from the current gain value to the target gain value.

[0079] In this embodiment, the drive module monitors the phase margin at different frequencies in real time while reducing the gain value. In the low-frequency band, it ensures the phase margin remains sufficiently large to prevent instability or oscillation caused by insufficient phase margin due to a rapid decrease in gain. In other frequency bands, it also keeps the phase margin within a reasonable range to ensure the stability and anti-interference capability of the closed-loop control. In this way, the gain value is gradually reduced from the current value to the target value, enabling the lens carrier to move smoothly to its natural position. It should be noted that in this embodiment, 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 adjustment of the gain value more reasonable, avoiding the control risk caused by blindly reducing the gain value, and improving the reliability of lens carrier movement control.

[0081] Based on the same publicly disclosed concept, see [link / reference] Figure 8 As shown, this embodiment of the present disclosure also provides a camera module 80, including a lens 2 and a voice coil motor control device 1 as described in any of the above embodiments.

[0082] Based on the same publicly disclosed concept, see [link / reference] Figure 9 As shown, this embodiment of the present disclosure also 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 device embodiments and the corresponding steps in the method embodiments are the same, but are not limited to the content disclosed in the above method embodiments. It should also be noted that the above modules, as part of the device, can be executed in a computer system such as a set of computer-executable instructions.

[0084] Those skilled in the art will understand that various aspects of this disclosure can be implemented in the following forms: a completely hardware implementation, a completely software implementation (including firmware, microcode, etc.), or a combination of hardware and software implementations, which can be collectively referred to herein as a "circuit", "module" or "system".

[0085] Based on the same disclosed concept, this disclosure also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the voice coil motor control method described above. Since the principle by which this computer-readable storage medium embodiment solves the problem is similar to that of the above method embodiments, the implementation of this computer-readable storage medium embodiment can refer to the implementation of the above method embodiments, and repeated details will not be elaborated further.

[0086] More specific examples of computer-readable storage media in this disclosure may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0087] In this disclosure, a computer-readable storage medium may include a data signal propagated in baseband or as part of a carrier wave, carrying 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, capable of transmitting, propagating, or transmitting a program for use by or in connection with an instruction execution system, apparatus, or device.

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

[0089] In practical implementation, program code for performing the operations of this disclosure can be written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Java and C++, and conventional procedural programming languages ​​such as C or similar languages. The program code can execute 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 cases involving remote computing devices, the remote computing device can 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 it can be connected to an external computing device (e.g., via the Internet using an Internet service provider).

[0090] Based on the same disclosed concept, this disclosure also provides a computer program product, including a computer program or instructions, which, when executed by a processor, implement the voice coil motor control method of any one of the above method embodiments. Since the principle by which this computer program product embodiment solves the problem is similar to that of the above method embodiments, the implementation of this computer program product embodiment can refer to the implementation of the above method embodiments, and repeated details will not be elaborated further.

[0091] It should be noted that although several modules or units for the device used to perform actions have been mentioned in the detailed description above, this division is not mandatory. In fact, according to embodiments of this disclosure, the features and functions of two or more modules or units described above can be embodied in one module or unit. Conversely, the features and functions of one module or unit described above can be further divided and embodied by multiple modules or units.

[0092] Furthermore, although the steps of the method in this disclosure are described in a specific order in the accompanying drawings, this does not require or imply that the steps must be performed in that specific order, or that all the steps shown must be performed to achieve the desired result. Additional or alternative steps may be omitted, multiple steps may be combined into one step, and / or a step may be broken down into multiple steps.

[0093] From the above description of the embodiments, those skilled in the art will readily understand that the exemplary embodiments described herein can be implemented by software or by combining software with necessary hardware. Therefore, the technical solutions according to the embodiments of this 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, external hard drive, etc.) or on a network, including several instructions to cause a computing device (such as a personal computer, server, mobile terminal, or network device, etc.) to execute the methods according to the embodiments of this disclosure.

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

Claims

1. A voice coil motor control method, characterized in that, include: In response to the power indication signal of the camera module, the current gain value and target gain value of the voice coil motor are obtained, wherein the target gain value corresponds to the target position of the lens carrier in the voice coil motor, and the current gain value, target gain value and target position are preset, and the power indication signal includes at least one of the following: power off signal, power down indication, signal or indication of switching from high power to low power; During the process of the lens carrier moving towards the target position, under the phase margin constraint, 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; A drive signal is generated based on the reduced gain value to control the lens carrier to move to the target position; 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 using a step-by-step method, wherein the number of steps in the step-by-step method is preset based on the parameter information of the camera module; or... The gain value is gradually reduced from the current gain value to the target gain value based on a constant rate, wherein the constant rate is preset according to the parameter information of the camera module; or, The gain value is gradually reduced from the current gain value to the target gain value based on a non-constant rate, wherein the non-constant rate is preset according to the parameter information of the camera module; The process of reducing the gain value does not depend on the real-time position feedback of the lens carrier.

2. The voice coil motor control method according to claim 1, characterized in that, 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, characterized in that, 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 the first phase of the lens carrier movement, the gain value is gradually reduced from the current gain value at a first rate. In the second phase of the lens carrier movement, 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.

4. The voice coil motor control method according to claim 1, characterized in that, 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.

5. The voice coil motor control method according to claim 1, characterized in that, The method further includes: Obtain the parameter information of the camera module; Based on the parameter information of the camera module, the gain value is gradually reduced from the current gain value to the target gain value.

6. The voice coil motor control method according to claim 1, characterized in that, After generating a drive signal based on the reduced gain value to control the lens carrier to move to the target position, the method further includes: Disconnect the power supply to the camera module.

7. The voice coil motor control method according to claim 1, characterized in that, The power indication signal is acquired in at least one of the following ways: The receiving control module receives a power-down instruction for the camera module; or, The receiving control module receives a power-off signal from the camera module; or, Detect the power status of the camera module.

8. A voice coil motor control device, characterized in that, include: The drive module is configured to acquire 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, and the current gain value, target gain value and target position are preset, and the power indication signal includes at least one of the following: power off signal, power down indication, signal or indication of switching from high power to low power; During the process of the lens carrier moving towards the target position, under the phase margin constraint, 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; A drive signal is generated based on the reduced gain value to control the lens carrier to move to the target position; The driver module is configured as follows: The gain value is gradually reduced from the current gain value to the target gain value using a step-by-step method, wherein the number of steps in the step-by-step method is preset based on the parameter information of the camera module; or... The gain value is gradually reduced from the current gain value to the target gain value based on a constant rate, wherein the constant rate is preset according to the parameter information of the camera module; or, The gain value is gradually reduced from the current gain value to the target gain value based on a non-constant rate, wherein the non-constant rate is preset according to the parameter information of the camera module; The process of reducing the gain value does not depend on the real-time position feedback of the lens carrier; The drive module includes peripheral circuitry; The peripheral circuitry is configured to set the current gain value and the target gain value; The drive module also includes a setting value setting unit for setting the target position of the lens carrier.

9. The voice coil motor control device according to claim 8, characterized in that, Also includes: The control module is configured to send a power-down instruction for the camera module to the drive module; or, The power-off signal of the camera module is output to the drive module.

10. The voice coil motor control device according to claim 8, characterized in that, The drive 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.

11. A camera module, characterized in that, It includes a lens and a voice coil motor control device as described in any one of claims 8-10.

12. An electronic device, characterized in that, include: processor; Memory used to store the processor's executable instructions; The processor is configured to execute the instructions to implement the voice coil motor control method as described in any one of claims 1-7.

13. A computer-readable storage medium storing instructions thereon, characterized in that, When the instructions in the computer-readable storage medium are executed by the processor of the electronic device, the electronic device is able to perform the voice coil motor control method as described in any one of claims 1-7.

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