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CN-121984302-A - Voice coil motor, control method of voice coil motor and photographic lens

CN121984302ACN 121984302 ACN121984302 ACN 121984302ACN-121984302-A

Abstract

The invention provides a voice coil motor, a control method of the voice coil motor and a photographic lens, and the voice coil motor comprises a coil assembly, a magnetic strip assembly and a magnetic yoke assembly, wherein the coil assembly comprises a first coil assembly and a second coil assembly, the first coil assembly and the second coil assembly are arranged at intervals along the axial direction and can move along the axial direction, the magnetic strip assembly comprises at least two groups of alternately arranged magnetic strips, the arrangement direction of the magnetic strips is parallel to the axial movement direction of the coil assembly, the magnetic yoke assembly comprises an inner magnetic yoke and an outer magnetic yoke, the inner magnetic yoke is embedded in the middle of each group of magnetic strips, the outer magnetic yoke is enclosed on the outer side of the coil assembly, the width-length ratio of the outer magnetic yoke is 11:20-13:20, the magnetic strip assembly and the magnetic yoke assembly are matched to form a closed electromagnetic loop, magnetic flux is generated in the area of the coil assembly, and the magnetic flux plane formed by the magnetic flux is parallel to the virtual plane of the axial movement direction of the coil, so that the magnetic field uniformity and the magnetic energy utilization rate are improved, the whole volume is reduced, and the running efficiency of the voice coil motor is effectively improved.

Inventors

  • LIU RUIJUN
  • CHEN BAOFENG

Assignees

  • 深圳市唯卓仕科技有限公司

Dates

Publication Date
20260505
Application Date
20260407

Claims (12)

  1. 1. A voice coil motor, the voice coil motor comprising: The coil assembly comprises a first coil assembly and a second coil assembly, wherein the first coil assembly and the second coil assembly are arranged at intervals along the axial direction and move along the axial direction; The magnetic stripe assembly comprises at least two groups of magnetic stripes which are alternately arranged, and the arrangement direction of the magnetic stripes is parallel to the axial movement direction of the coil assembly; The magnetic yoke assembly comprises an inner magnetic yoke and an outer magnetic yoke, the inner magnetic yoke is embedded in the middle of each group of magnetic strips, the outer magnetic yoke is enclosed on the outer side of the coil assembly, and at least part of the outer periphery of the coil assembly is wrapped; The width-length ratio of the outer magnetic yoke is 11:20-13:20, the magnetic strip component and the magnetic yoke component are matched to form a closed electromagnetic loop, magnetic flux is generated in the area of the coil component, and a magnetic flux surface formed by the magnetic flux is parallel to a virtual plane in the axial movement direction of the coil.
  2. 2. The voice coil motor of claim 1, wherein the magnetic stripe is a concave magnetic stripe comprising two oppositely disposed long side surfaces, two oppositely disposed short side surfaces, and oppositely disposed first and second surfaces; The two oppositely arranged long side surfaces are respectively sunken towards the central axis direction of the magnetic stripe, the indent depth of the long side surfaces is 0.8-1.2 mm, the indent radian is 90 degrees, the two oppositely arranged short side surfaces are respectively sunken towards the central axis direction of the magnetic stripe, and the indent depth of the short side surfaces is 0.8-1.2 mm, and the indent radian is 60 degrees.
  3. 3. The voice coil motor of claim 2, wherein the inner yoke comprises a first bonding surface and a second bonding surface disposed opposite to each other, and a circumferential side surface disposed between the first bonding surface and the second bonding surface, wherein the first bonding surface of the inner yoke and the second surface of the magnetic stripe are disposed in a mutually bonded manner, and the second bonding surface of the inner yoke and the first surface of the magnetic stripe are disposed in a mutually bonded manner.
  4. 4. The voice coil motor of claim 1, wherein the outer yoke comprises a first side wall, a third side wall, and a second side wall connecting the first side wall and the third side wall, which are disposed opposite to each other, wherein an opening is formed between the first side wall and the third side wall toward the coil block, and the outer yoke wraps at least a part of an outer circumference of the coil block through the opening.
  5. 5. The voice coil motor of claim 1, wherein the coil assembly occupies less than or equal to 30% of the cross-sectional area of the complete flux linkage generated by the magnetic stripe assembly in a cross-section perpendicular to the inner yoke.
  6. 6. The voice coil motor of claim 1, wherein a length ratio of the magnetic stripe to the inner yoke in a connection direction is 3:1 to 4:1.
  7. 7. The voice coil motor of claim 1, further comprising a sleeve made of a magnetically non-conductive metallic material, the sleeve being wrapped around the magnetic strip and the outer peripheral wall of the inner yoke.
  8. 8. A control method for the voice coil motor according to any one of claims 1 to 7, the voice coil motor being provided in a moving group assembly, characterized in that the control method for the voice coil motor comprises the steps of: Acquiring a target position to which the movable group assembly is to be moved, and acquiring a current position of the movable group assembly through a position detection device, wherein the position detection device comprises a magnetic grid and a magnetic sensor; Calculating the position deviation of the movable group assembly according to the target position of the movable group assembly and the current position, and generating a current control instruction according to the position deviation and a preset PID control parameter; and controlling the voice coil motor to generate corresponding electromagnetic driving force through the current control instruction, and driving the movable group assembly to move to the target position through the electromagnetic driving force.
  9. 9. The method of controlling a voice coil motor according to claim 8, wherein the step of acquiring the current position of the moving group assembly by the position detecting means comprises: Acquiring a first sine signal and a first cosine signal with a phase difference of 90 degrees through the magnetic sensor; amplifying and filtering the first sine signal and the first cosine signal respectively to obtain a second sine signal and a second cosine signal; Calculating the bias voltage and the amplitude voltage of the second sine signal and the bias voltage and the amplitude voltage of the second cosine signal; based on the bias voltage and the amplitude voltage, respectively carrying out normalization processing on the second sine signal and the second cosine signal to obtain a normalized sine signal and a normalized cosine signal; And performing anti-angle calculation on the normalized sine signal and the normalized cosine signal to obtain the current position of the dynamic group component.
  10. 10. The method of claim 8, wherein the step of generating the current control command according to the position deviation and a preset PID control parameter comprises: And judging a polarity region of a magnetic field where the coil assembly is positioned according to the current position, determining a current direction of the coil assembly based on the polarity region, and determining a current amplitude of the coil assembly according to the position deviation and PID control parameters.
  11. 11. The method of controlling a voice coil motor of claim 10, wherein the step of determining the current direction of the coil assembly based on the polarity region comprises: When the coil assembly moves to the NS magnetic field loop, controlling the current of the coil assembly to be clockwise; when the coil assembly moves to the SN magnetic field loop, controlling the current of the coil assembly to be in a counterclockwise direction; When the coil assembly enters the SN magnetic field loop from the NS magnetic field loop or enters the NS magnetic field loop from the SN magnetic field loop, the current of the coil assembly is set to zero, the current direction of the coil assembly is controlled to change, and the PID control parameters are updated.
  12. 12. The photographic lens is characterized by comprising at least one group of movable group components, wherein each movable group component comprises a lens, a lens frame, a guide pillar, a position detection device and a voice coil motor according to any one of claims 1 to 7, the lens is fixedly arranged in the lens frame, the guide pillar and the voice coil motor are all arranged at equal intervals along the circumferential direction of the lens frame, the position detection device is arranged on the outer circumferential side of the lens frame, and the position detection device is electrically connected with the voice coil motor.

Description

Voice coil motor, control method of voice coil motor and photographic lens Technical Field The invention relates to the technical field of voice coil motors, in particular to a voice coil motor, a control method of the voice coil motor and a photographic lens. Background The existing lens Voice Coil Motor (VCM) is widely applied to an automatic focusing system of a camera module, and the magnetic field distribution and thrust stability of the Voice Coil Motor directly affect the imaging quality and positioning accuracy. However, the existing lens voice coil motor generally has the problem of uneven magnetic field distribution, magnetic induction flux cut by the coil in the motion process changes along with the nonlinearity of the position, so that output thrust fluctuation is obvious, operation stability is poor, and focusing requirements of high precision and high stability are difficult to meet. Meanwhile, the traditional magnetic circuit design has obvious magnetic leakage, the magnetic energy utilization rate is low, not only the driving efficiency is low, but also part of electric energy is converted into heat energy instead of mechanical energy, so that the power consumption and heat generation of the motor are easy to increase in the working process, and the development of the motor towards the direction of light weight and low power consumption is limited. In addition, the magnetic energy utilization rate of the traditional voice coil motor is low, the effective acting area of the coil is limited to a section with a strong magnetic field, the electromagnetic force contributed by the coil section in the area with a weak magnetic field or a direction change area is small, so that the magnetic energy waste is caused, meanwhile, the large thrust and the high stability are difficult to be compatible in the limited volume, and the thrust density and the control precision of the motor are limited. Therefore, the existing lens voice coil motor has room for improvement in the aspects of magnetic field distribution uniformity, thrust stability, magnetic energy utilization rate, structural compactness, heat dissipation performance and the like. Disclosure of Invention The invention aims to provide a voice coil motor, a control method of the voice coil motor and a photographic lens, and aims to solve the problems of uneven magnetic field distribution, unstable thrust and low magnetic energy utilization rate of the traditional voice coil motor. In a first aspect, the present invention provides a voice coil motor comprising: The coil assembly comprises a first coil assembly and a second coil assembly, wherein the first coil assembly and the second coil assembly are arranged at intervals along the axial direction and move along the axial direction; The magnetic stripe assembly comprises at least two groups of magnetic stripes which are alternately arranged, and the arrangement direction of the magnetic stripes is parallel to the axial movement direction of the coil assembly; The magnetic yoke assembly comprises an inner magnetic yoke and an outer magnetic yoke, the inner magnetic yoke is embedded in the middle of each group of magnetic strips, the outer magnetic yoke is enclosed on the outer side of the coil assembly, and at least part of the outer periphery of the coil assembly is wrapped; The width-length ratio of the outer magnetic yoke is 11:20-13:20, the magnetic strip component and the magnetic yoke component are matched to form a closed electromagnetic loop, magnetic flux is generated in the area of the coil component, and a magnetic flux surface formed by the magnetic flux is parallel to a virtual plane in the axial movement direction of the coil. In some embodiments, the magnetic stripe is a concave magnetic stripe, and includes two oppositely disposed long side surfaces, two oppositely disposed short side surfaces, and oppositely disposed first and second surfaces; The two oppositely arranged long side surfaces are respectively sunken towards the central axis direction of the magnetic stripe, the indent depth of the long side surfaces is 0.8-1.2 mm, the indent radian is 90 degrees, the two oppositely arranged short side surfaces are respectively sunken towards the central axis direction of the magnetic stripe, and the indent depth of the short side surfaces is 0.8-1.2 mm, and the indent radian is 60 degrees. In some embodiments, the inner yoke is substantially in a cuboid structure, and comprises a first bonding surface and a second bonding surface which are oppositely arranged, and a circumferential side surface positioned between the first bonding surface and the second bonding surface, wherein the first bonding surface of the inner yoke and the second surface of the magnetic strip are mutually bonded, and the second bonding surface of the inner yoke and the first surface of the magnetic strip are mutually bonded. In some embodiments, the outer yoke comprises a first side wall, a third side wall and a