CN111447367B - Voice coil motor, driving method, camera module and computer readable storage medium - Google Patents
Voice coil motor, driving method, camera module and computer readable storage medium Download PDFInfo
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- CN111447367B CN111447367B CN202010380168.5A CN202010380168A CN111447367B CN 111447367 B CN111447367 B CN 111447367B CN 202010380168 A CN202010380168 A CN 202010380168A CN 111447367 B CN111447367 B CN 111447367B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
- H04N23/60—Control of cameras or camera modules
- H04N23/67—Focus control based on electronic image sensor signals
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Abstract
The present application relates to a voice coil motor, a driving method, a camera module, and a computer-readable storage medium, the voice coil motor including: a substrate; the first magnet is arranged on the substrate and used for generating a first magnetic field; the first coil is fixedly arranged with the lens and used for pushing the lens to move according to a first driving signal, and the first magnetic field covers the first coil; the second magnet is fixedly arranged with the lens and used for generating a second magnetic field; and the first tunnel magnetic resistance TMR element is arranged on the substrate and used for generating a second driving signal according to the detected second magnetic field, and the second driving signal is used for adjusting the lens from the current position to the target position. The voice coil motor provided by the application comprises a first TMR element arranged on a substrate, wherein the first TMR element can acquire the current position of a lens and generate a second driving signal by utilizing a far detection distance. The voice coil motor provided by the application has high focusing accuracy rate and can meet the miniaturization requirement.
Description
Technical Field
The present application relates to influence, and more particularly, to a voice coil motor, a driving method, a camera module, and a computer-readable storage medium.
Background
With the development of imaging technology, people are more and more accustomed to shooting images or videos through image acquisition equipment such as a camera on electronic equipment and recording various information. The camera module comprises a voice coil motor and a camera, wherein a first coil in the voice coil motor moves under the action of an electromagnetic effect and pushes the camera to move to a target focusing position, so that focusing is performed and an image is collected.
However, the volume of the existing voice coil motor is large, and the requirement of miniaturization of the camera module cannot be met.
Disclosure of Invention
The embodiment of the application provides a voice coil motor, a driving method, a camera module and a computer readable storage medium, and can improve the voice coil motor to meet the miniaturization requirement.
A voice coil motor for driving a lens to move, the voice coil motor comprising:
a substrate;
the first magnet is arranged on the substrate and used for generating a first magnetic field;
the first coil is fixedly arranged with the lens and used for pushing the lens to move according to a first driving signal, and the first magnetic field covers the first coil;
the second magnet is fixedly arranged with the lens and used for generating a second magnetic field;
and the first tunnel magnetic resistance TMR element is arranged on the substrate and used for generating a second driving signal according to the detected second magnetic field, and the second driving signal is used for adjusting the lens from the current position to the target position.
A driving method is applied to a voice coil motor, wherein the voice coil motor is used for driving a lens to move, and the method comprises the following steps:
controlling a first coil to push the lens to move according to a first driving signal, wherein a first magnetic field generated by a first magnet covers the first coil;
controlling a second magnet to generate a second magnetic field, wherein the second magnet is fixedly arranged with the lens;
and controlling a first TMR element arranged on the substrate to generate a second driving signal according to the detected second magnetic field, wherein the second driving signal is used for adjusting the lens from the current position to the target position.
A camera module, comprising:
a lens;
the voice coil motor is used for driving the lens to move.
A camera module comprising a memory, a processor and a voice coil motor, wherein the memory stores a computer program, and the computer program, when executed by the processor, causes the processor to execute the steps of the driving method.
A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out the steps of the driving method as described.
The voice coil motor, the driving method, the camera module and the computer readable storage medium, wherein the voice coil motor comprises: a substrate; the first magnet is arranged on the substrate and used for generating a first magnetic field; the first coil is fixedly arranged with the lens and used for pushing the lens to move according to a first driving signal, and the first magnetic field covers the first coil; the second magnet is fixedly arranged with the lens and used for generating a second magnetic field; and the first tunnel magnetic resistance TMR element is arranged on the substrate and used for generating a second driving signal according to the detected second magnetic field, and the second driving signal is used for adjusting the lens from the current position to the target position. The voice coil motor provided by the application comprises a first TMR element arranged on a substrate, wherein the first TMR element can acquire the current position of a lens and generate a second driving signal by utilizing a far detection distance, and the second driving signal is used for adjusting the lens from the current position to a target position, so that the focusing of closed-loop feedback is realized. The voice coil motor provided by the application has high focusing accuracy rate and can meet the miniaturization requirement.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a diagram of an exemplary voice coil motor;
FIG. 2 is a schematic diagram of a voice coil motor according to an embodiment;
FIG. 3 is a schematic view of a voice coil motor according to another embodiment;
FIG. 4a is a top view of a voice coil motor in one embodiment;
FIG. 4b is a top view of a voice coil motor in accordance with yet another embodiment;
FIG. 4c is a top view of a voice coil motor in accordance with yet another embodiment;
FIG. 4d is a top view of the voice coil motor in accordance with the new embodiment;
FIG. 5 is a block diagram of a camera module according to an embodiment;
FIG. 6 is a flow chart of a driving method in one embodiment;
FIG. 7 is a flowchart of a driving method in still another embodiment;
fig. 8 is a flowchart of steps for controlling the second TMR element to acquire an offset amount of the lens at the target position according to the detected second magnetic field in one embodiment.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.
It will be understood that, as used herein, the terms "first," "second," and the like may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, a first magnet may be referred to as a second magnet, and similarly, a second magnet may be referred to as a first magnet, without departing from the scope of the present application. The first magnet and the second magnet are both magnets, but they are not the same magnet.
The embodiment of the present application provides a Voice Coil Motor 20 (VCM), which is applied to an electronic device. The electronic device may be any terminal device capable of focusing, such as a mobile phone, a tablet computer, a PDA (Personal Digital Assistant), a Point of Sales (POS), a vehicle-mounted computer, and a wearable device. As shown in fig. 1, a camera module includes a lens 10 and a voice coil motor 20. As shown in fig. 2, the voice coil motor 20 includes: a lens barrel 210, a first magnet 220, a first coil 230, a second magnet 240, a Tunnel Magnetoresistive (TMR) element 250, and a driving unit 260. The operation principle of the voice coil motor 20 is that in a magnetic field, the first coil 230 is controlled to generate a force by changing the current of the first coil 230 to push the lens barrel 210 for mounting the lens 10 to move, so that the lens 10 is controlled to move by controlling the current of the first coil 230 to move the lens 10 to a target position and focus. The voice coil motor 20 is applied to a camera module for focusing due to advantages of small volume and mass, fast response speed (millisecond level), simple and reliable control, maintenance-free, long service life, high position precision level and the like.
And a lens barrel 210 for mounting the lens 10.
Specifically, the lens barrel 210 is a component for mounting the lens 10, and the size of the lens barrel 210 is adjusted according to the size of the lens 10. The lens 10 refers to an optical component in a camera module, and the lens 10 can be classified into a standard lens, a wide-angle lens, a telescope head, and the like according to the focal length, and the different lenses 10 are slightly different in size.
The first magnet 220 is disposed on the substrate 270 and configured to generate a first magnetic field.
The first magnet 220 is configured to generate a stable bias magnetic field, which is referred to as a first magnetic field, and the first magnetic field covers the first coil 230. The number of the first magnets 220 may be plural, and the plural first magnets 220 collectively generate the first magnetic field. The plurality of first magnets 220 are all disposed on the substrate 270, and the plurality of first magnets 220 are fixed in position and may be uniformly distributed around the outer side of the first coil 230. For example, taking the first coil 230 as a circular ring as an example, if the vcm 20 includes 3 first magnets 220, an included angle between the 3 first magnets 220 is 120 degrees. If the vcm 20 includes 4 first magnets 220, an included angle between the 4 first magnets 220 is 90 degrees; if the vcm 20 includes 6 first magnets 220, the included angle between the 6 first magnets 220 is 60 degrees, that is, the first magnets 220 are uniformly distributed on the first coil 230. The plurality of first magnets 220 generate a stable first magnetic field, the first magnetic field covers the first coil 230, and the first coil 230 is fixedly disposed on the lens barrel 210. When the first coil 230 is energized, an acting force is generated due to an electromagnetic effect, and the acting force acts on the lens barrel 210 to push the lens barrel 210 to move up and down, so as to drive the lens 10 to move for focusing. That is, the moving position of the lens 10 can be controlled by controlling the current applied to the first coil 230, thereby achieving focusing. The shape of the first magnet 220 is not limited, and may be a cube, a cylinder, or the like. In one embodiment, the side of the first magnet 220 adjacent to the first coil 230 is a curved surface, and the curvature of the curved surface matches the curvature of the first coil 230.
The first coil 230 is fixed to the lens barrel 210 and the lens 10, and is configured to push the lens barrel 210 to move according to a first driving signal. Wherein the first magnetic field covers the first coil 230.
Specifically, the first coil 230 is fixed to the lens barrel 210, the first coil 230 may be wound on the lens barrel 210, and the first coil 230 may be etched on a sidewall of the lens barrel 210. Since the lens barrel 210 is used to mount the lens 10, the first coil 230 is fixedly disposed with the lens 10. Wherein the first driving signal may be a current signal and the first magnetic field covers the first coil 230. When the first coil 230 is energized by the first driving signal, a force for pushing the lens barrel 210 to move is generated according to the signal intensity of the first driving signal, such as an energizing current, and the magnitude of the force corresponds to the signal intensity of the first driving signal. The lens barrel 210 moves up and down to a target position under the pushing of the acting force, and the target position corresponds to the signal intensity of the first driving signal. When the signal intensity of the first driving signal is larger, the target position is farther from the original position; when the signal intensity of the first driving signal is smaller, the target position is closer to the original position. It should be noted that, due to environmental factors such as device accuracy of the voice coil motor 20 and stability of the focusing algorithm, after the first driving signal is applied, the current position to which the voice coil motor 20 pushes the lens 10 to move has a movement error with the target position.
And a second magnet 240 fixedly disposed with the barrel 210 for generating a second magnetic field.
Specifically, the second magnet 240 has a small volume, is fixedly disposed with the lens barrel 210, and can move up and down along with the lens barrel 210 and the lens 10, and the second magnet 240 generates the second magnetic field no matter in a stationary state or a moving state. It should be noted that the first coil 230 is also fixed to the lens barrel 210, that is, the relative position of the second magnet 240 and the first coil 230 is fixed, when the first coil 230 is energized to generate a force for pushing the lens barrel 210 to move, the second magnet 240 moves synchronously with the lens barrel 210, and the second magnet 240 and the lens barrel 210 are relatively stationary. Obviously, the position of the second magnet 240 may represent the position of the lens barrel 210, and the lens 10 for capturing an image is installed in the lens barrel 210, that is, the position of the second magnet 240 may represent the focusing position of the lens 10.
And a first TMR element 250 disposed on the substrate 270, for generating a second driving signal according to the detected second magnetic field, the second driving signal being used to adjust the lens 10 from the current position to the target position.
Specifically, the first TMR element 250 is a sensor based on the tunnel magnetoresistance effect, and has characteristics such as high output, high accuracy, small temperature drift and aging, and high stability. First TMR element 250 is provided on substrate 270, and is held fixed with the position of first magnet 220. The first TMR element 250 is used to detect the magnetic field strength of the second magnetic field generated by the second magnet 240. When the second magnet 240 moves up and down following the lens barrel 210, the magnetic field strength of the second magnetic field detected by the first TMR element 250 changes simultaneously. When second magnet 240 moves in a direction away from first TMR element 250 following lens barrel 210, the magnetic field strength of the second magnetic field detected by first TMR element 250 becomes small. When the second magnet 240 moves in the direction in which the first TMR element 250 is located following the lens barrel 210, the magnetic field strength of the second magnetic field detected by the first TMR element 250 becomes large. Since the magnetic field strength of the second magnetic field detected by the first TMR element 250 can reflect the position of the second magnet 240, i.e. can reflect the current position of the lens 10, the first TMR element 250 generates a second drive signal according to the detected magnetic field strength of the second magnetic field, the second drive signal can represent the current position of the lens 10. The second driving signal may be a voltage signal for transmission to the driving unit 260. The driving unit 260 will obtain the driving compensation strategy according to the magnitude of the second driving signal. When the target position identified by the second driving signal does not match the target position, the driving compensation strategy compensates the current position of the lens 10 to adjust the current position to the target position.
The voice coil motor 20 includes: a substrate 270; a first magnet 220 disposed on the substrate 270 for generating a first magnetic field; a first coil 230 fixedly disposed with the lens 10 for driving the lens 10 to move according to a first driving signal, wherein the first magnetic field covers the first coil 230; a second magnet 240 fixedly disposed with the lens 10 for generating a second magnetic field; and a first TMR element 250 disposed on the substrate 270, for generating a second driving signal according to the detected second magnetic field, the second driving signal being used to adjust the lens 10 from the current position to a target position, the target position corresponding to the first driving signal. The voice coil motor 20 provided by the present application includes a first TMR element 250 disposed on a substrate 270, and the first TMR element 250 can acquire a current position of the lens 10 and generate a second driving signal by having a longer detection distance, and the second driving signal is used to adjust the lens 10 from the current position to a target position, thereby realizing focusing of closed-loop feedback. The voice coil motor 20 provided by the application has high focusing accuracy and can meet the miniaturization requirement.
In one embodiment, as shown in fig. 3, the voice coil motor 20 further includes: and an optical anti-shake component 280 for generating a third driving signal according to the detected offset of the lens 10 at the target position, and compensating the offset according to the third driving signal.
Specifically, the optical anti-shake element is capable of detecting the amount of shift of the lens 10 at the target position, such as shake, cut-off, and the like in the vertical direction and the horizontal direction. And generating a third driving signal according to the detected offset and transmitting the third driving signal to the driving unit, wherein the driving unit can compensate the offset according to the third driving signal. It should be noted that the second driving signal is used to coarsely adjust the lens 10 to the target position in a first step, and the third driving signal is used to finely adjust the lens 10 to the target position in a second step, where the first step is larger than the second step. That is, the optical anti-shake assembly 280 can reduce shake during movement of the lens 10, and improve precision and stability of the lens 10 adjusted by the voice coil motor 20.
In one embodiment, as shown in fig. 3, the optical anti-shake assembly 280 further includes: a second TMR element 281 disposed on the substrate 270 for obtaining an offset amount according to the detected second magnetic field and generating a third driving signal according to the offset amount; the second coil 282 is fixedly disposed on the lens 10, and is used for driving the lens 10 to move according to the third driving signal, so as to compensate the offset.
Specifically, the optical anti-shake element includes a second TMR element 281 and a second coil 282, the second TMR element 281 is disposed on the substrate 270, and may be disposed on the same surface of the substrate 270 as the first TMR element 250, the second coil 282 is disposed fixedly with the lens 10, and the first magnetic field covers the second coil 282. The second TMR element 281 is capable of detecting the shift amount of the lens 10 at the target position, such as shake, shear tilt, and the like in the vertical direction and the horizontal direction. For example, when the lens 10 is moved by the urging of the first coil, the second TMR element 281 detects a change in the second magnetic field, and the detected change in the magnetic field strength of the second magnetic field can identify the shift amount of the lens at the target position. The second TMR element 281 may generate a third driving signal according to the offset amount and transmit the third driving signal to the second coil 282. The second coil 282 can push the lens 10 to move to compensate for the offset during the energization of the third driving signal.
In one embodiment, the third driving signal includes a first direction driving signal and a second direction driving signal, and as shown in fig. 3, the second TMR element 281 includes: a first-direction TMR sensor 281a for acquiring an offset amount in a first direction during movement of the lens 10 and generating a first-direction drive signal according to the offset amount in the first direction; and a second-direction TMR sensor 281b for acquiring an offset amount in a second direction during the movement of the lens 10, and generating a second-direction driving signal according to the offset amount in the second direction, wherein the first direction is perpendicular to the second direction.
Specifically, the second TMR element 281 may refer to a plurality of TMR sensors, and may detect a shake or tilt-generated offset in a plurality of directions. As the second TMR element 281, it includes: a first-direction TMR sensor 281a and a second-direction TMR sensor 281 b. The first direction is perpendicular to the second direction, and when the first direction is a horizontal direction, the second direction is a vertical direction, and when the first direction is a vertical direction, the second direction is a horizontal direction. The first direction TMR sensor 281a is configured to obtain an offset amount in the first direction during the movement of the lens 10 and generate a first direction driving signal according to the offset amount in the first direction, and transmit the first direction driving signal to the second coil 282, so that the second coil 282 pushes the lens 10 to move according to the first direction driving signal, thereby compensating the offset amount of the lens 10 in the first direction. And a second-direction TMR sensor 281b for acquiring an offset amount in the second direction during the movement of the lens 10 and generating a second-direction driving signal according to the offset amount in the second direction, and transmitting the second-direction driving signal to the second coil 282, so that the second coil 282 pushes the lens 10 to move according to the second-direction driving signal, thereby compensating the offset amount of the lens 10 in the second direction.
In one embodiment, the voice coil motor 20 further includes a driving unit 260 connected to the first coil 230 and the first TMR element 250, for generating and transmitting a first driving signal to the first coil 230, and for adjusting the lens 10 from the current position to the target position according to a second driving signal.
Specifically, the driving unit 260 can generate a first driving signal according to a focusing algorithm, the first driving signal is transmitted to the first coil 230 to energize the first coil 230, so that the first coil 230 generates an acting force for pushing the lens 10 to move, and the magnitude of the first driving signal corresponds to the magnitude of the acting force. Driving unit 260 is further configured to receive a second driving signal transmitted by first TMR element 250, and obtain a driving compensation strategy according to the magnitude of the second driving signal. For example, the driving unit 260 receives the second driving signal and detects whether the current position of the lens 10 identified by the second driving signal matches the target position corresponding to the first driving signal. When the second driving signal identifies that the current position of the lens 10 matches the target position, the driving unit 260 does not need to adjust the current position of the lens 10, and can also generate a prompt signal for identifying accurate focusing; when the second driving signal indicates that the current position of the lens 10 is not matched with the target position, the driving unit 260 adjusts the current position of the lens 10 to the target position according to the magnitude of the second driving signal, and if the current position of the lens 10 is lower than the target position, the lens 10 is adjusted upward to the target position according to the second driving signal if the current position of the lens 10 is in the moving direction in the vertical direction; when the current position of the lens 10 is higher than the target position, the lens 10 is adjusted downward to the target position according to the second driving signal.
In one embodiment, the vcm 20 includes a plurality of first magnets 220, and the plurality of first magnets 220 are uniformly distributed outside the first coil 230.
Specifically, the voice coil motor 20 includes a plurality of first magnets 220, and the plurality of first magnets 220 can generate a stable first magnetic field having a strong magnetic force. Since the magnitude of the acting force F generated by the first coil 230 depends on the magnetic field strength B of the first magnetic field, the length L of the wire of the first coil 230, and the magnitude of the energizing current I corresponding to the first driving signal, denoted by F ═ BIL by a common representation. That is, the larger the first magnetic field strength is, the stronger the force generated to move the lens 10 is. In addition, if one first magnet 220 is used to generate the first magnetic field having the magnetic field strength of B1, the volume of the first magnet 220 is inevitably large, and the plurality of first magnets 220 can be distributed at different positions on the substrate 270, thereby reducing the volume space and improving the advantage of downsizing the voice coil motor 20. The plurality of first magnets 220 are all disposed on the substrate 270, and the plurality of first magnets 220 are fixed in position and uniformly distributed around the outer side of the first coil 230, so that the first magnetic field generated by the plurality of first magnets 220 covers the first coil 230. The plurality of first magnetic fields are distributed uniformly, the generated first magnetic fields uniformly cover the first coil 230, and the first coil 230 is energized according to the first driving signal to generate a stable acting force to push the lens 10 to move. For example, taking the first coil 230 as a circular ring as an example, as shown in fig. 4a, if the vcm 20 includes 3 first magnets 220, an included angle between the 3 first magnets 220 is 120 degrees; as shown in fig. 4b and 4c, if the vcm 20 includes 4 first magnets 220, an included angle between the 4 first magnets 220 is 90 degrees; as shown in fig. 4d, if the vcm 20 includes 6 first magnets 220, the included angle between the 6 first magnets 220 is 60 degrees, that is, the first magnets 220 are uniformly distributed on the first coil 230. The plurality of first magnets 220 generate a stable first magnetic field, the first magnetic field covers the first coil 230, and the first coil 230 is fixedly disposed on the lens barrel 210. In this embodiment, the first coil 230 generates a stable acting force to push the lens 10 to move for focusing, so as to reduce the jitter and tilt of the lens 10 during the moving process, thereby reducing the focusing error.
In one embodiment, as shown in fig. 4b and 4c, the voice coil motor 20 includes four first magnets 220.
Specifically, the voice coil motor 20 includes four first magnets 220, the first coil 230 is often annular, and the four first magnets 220 are uniformly distributed outside the first coil 230. As shown in fig. 4b, the first magnet 220a, the first magnet 220b, the first magnet 220c, and the first magnet 220d are sequentially arranged in the clockwise direction. If the first coil 230 is circular, a first straight line formed by connecting the first magnet 220a and the first magnet 220c passes through the center of the first coil 230, a second straight line formed by connecting the first magnet 220b and the first magnet 220d passes through the center of the first coil 230, and the first straight line and the second straight line are perpendicular to each other. As shown in fig. 4c, a first straight line formed by the first magnet 220a and the first magnet 220c may be a vertical line passing through the center of the circle, and a second straight line formed by the first magnet 220b and the first magnet 220d connected to each other may be a horizontal line passing through the center of the circle. In this embodiment, the four first magnets 220 can satisfy both the requirement of generating the first magnetic field having a strong magnetic force and the requirement of downsizing the voice coil motor 20.
In one embodiment, first magnet 220 and first TMR element 250 are disposed on the same surface of substrate 270.
Specifically, the first magnet 220 and the first TMR element 250 are both provided on the substrate 270, and the first magnet 220 and the first TMR element 250 are relatively stationary. By disposing the first magnet 220 and the first TMR element 250 on the same surface of the substrate 270, the size of the voice coil motor 20 in the vertical direction can be reduced, the size of the voice coil motor 20 in the Z direction can be reduced, and the volume advantage of the voice coil motor 20 can be improved.
In one embodiment, the thickness of first TMR element 250 is less than or equal to the thickness of first magnet 220.
Specifically, the thickness of the first TMR element 250 is lower than the thickness of the first magnet 220, and when the voice coil motor 20 includes a plurality of first magnets 220, the thickness of the first TMR element 250 is lower than the thickness of each first magnet 220. Setting the thickness of first TMR element 250 to be lower than the thickness of first magnet 220 can prevent the size of voice coil motor 20 in the z direction from being increased due to the large thickness of first TMR element 250, thereby improving the volume advantage of voice coil motor 20.
In one embodiment, the driving unit 260 includes: a generation subunit for generating a first drive signal; and an obtaining subunit, configured to obtain a current position of the lens 10 according to the second driving signal, and obtain a driving compensation strategy according to the current position.
Specifically, the driving unit 260 may include a generating subunit, and the generating subunit may generate a first driving signal according to a focusing algorithm, and transmit the first driving signal to the first coil 230, so as to energize the first coil 230, and generate an acting force for pushing the lens 10 to move under the action of an electromagnetic effect after the first coil 230 is energized, where a signal magnitude of the first driving signal corresponds to a magnitude of the acting force. The driving unit 260 further includes an obtaining sub-unit for receiving the second driving signal transmitted from the first TMR element 250 and obtaining a driving compensation strategy according to the magnitude of the second driving signal. When the target position identified by the second driving signal does not match the target position, the driving compensation strategy compensates the current position of the lens 10 to adjust the current position to the target position. For example, the driving unit 260 receives the second driving signal and detects whether the current position of the lens 10 identified by the second driving signal matches the target position corresponding to the first driving signal. When the second driving signal identifies that the current position of the lens 10 matches the target position, the driving unit 260 may generate a prompt signal indicating that the focusing is accurate without adjusting the current position of the lens 10; when the second driving signal identifies that the current position of the lens 10 is not matched with the target position, the driving unit 260 acquires a driving compensation strategy according to the magnitude of the second driving signal, so as to adjust the current position of the lens 10 to the target position, and if the current position of the lens 10 is lower than the target position, the lens 10 is adjusted upward to the target position according to the second driving signal if the vertical direction is taken as the moving direction; when the current position of the lens 10 is higher than the target position, the lens 10 is adjusted downward to the target position according to the second driving signal.
The division of each module in the driving unit is only used for illustration, and in other embodiments, the driving unit may be divided into different modules as needed to complete all or part of the functions of the driving unit.
For the specific definition of the driving unit, reference may be made to the above definition of the driving method, which is not described herein again. The respective modules in the above-described driving unit may be wholly or partially implemented by software, hardware, and a combination thereof. The modules can be embedded in a hardware form or independent from a processor in the computer device, and can also be stored in a memory in the computer device in a software form, so that the processor can call and execute operations corresponding to the modules.
Fig. 5 is a schematic internal structure diagram of the camera module in one embodiment. As shown in fig. 5, the head module includes a processor, a memory, and a voice coil motor connected by a system bus. Wherein, the processor is used for providing calculation and control capability and supporting the operation of the whole electronic equipment. The memory may include a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The computer program can be executed by a processor to implement a driving method provided in the following embodiments. The internal memory provides a cached execution environment for the operating system computer programs in the non-volatile storage medium.
The present application provides a driving method, as shown in fig. 6, for a voice coil motor, the driving method includes: step 602 to step 606.
Specifically, the driving unit can generate a first driving signal according to a focusing algorithm, the first driving signal is transmitted to the first coil to electrify the first coil, so that the first coil generates an acting force for pushing the lens to move, and the signal magnitude of the first driving signal corresponds to the magnitude of the acting force. When the first coil is electrified by using the first driving signal, acting force for pushing the lens barrel to move is generated according to the first driving signal, such as the signal intensity of the electrified current, and the magnitude of the acting force corresponds to the signal intensity of the first driving signal. The lens barrel moves up and down to a target position under the pushing of the acting force, and the target position corresponds to the signal intensity of the first driving signal. When the signal intensity of the first driving signal is larger, the target position is farther from the original position; when the signal intensity of the first driving signal is smaller, the target position is closer to the original position.
And step 604, controlling a second magnet to generate a second magnetic field, wherein the second magnet is fixedly arranged with the lens.
Specifically, the volume of second magnet is less, and with the fixed setting of lens cone, can follow lens cone and camera lens and reciprocate, no matter under quiescent condition or moving state, the second magnet all produces the second magnetic field. The first TMR element is provided on the substrate, and is held in a fixed position with respect to the first magnet. The first TMR element detects a magnetic field strength of the second magnetic field generated by the second magnet.
And 606, controlling the first tunnel magnetic resistance TMR element arranged on the substrate to generate a second driving signal according to the detected second magnetic field, wherein the second driving signal is used for adjusting the lens from the current position to a target position, and the target position corresponds to the first driving signal.
Specifically, when the second magnet moves up and down along with the lens barrel, the magnetic field intensity of the second magnetic field detected by the first TMR element changes synchronously. When the second magnet moves in a direction away from the first TMR element following the lens barrel, the magnetic field strength of the second magnetic field detected by the first TMR element becomes small. When the second magnet moves in the direction in which the first TMR element is located following the lens barrel, the magnetic field strength of the second magnetic field detected by the first TMR element becomes large. The first TMR element generates a second driving signal according to the detected magnetic field intensity of the second magnetic field, and the second driving signal can represent the current position of the lens. The second driving signal may be a voltage signal transmitted to the driving unit. For example, the driving unit receives the second driving signal and detects whether the current position of the lens identified by the second driving signal matches the target position corresponding to the first driving signal. When the second driving signal identifies that the current position of the lens is matched with the target position, the driving unit does not need to adjust the current position of the lens and can also generate a prompt signal for identifying accurate focusing; when the second driving signal identifies that the current position of the lens is not matched with the target position, the driving unit acquires a driving compensation strategy according to the magnitude of the second driving signal, the driving compensation strategy adjusts the current position of the lens to the target position, if the vertical direction is taken as the moving direction, and when the current position of the lens is lower than the target position, the lens is adjusted upwards to the target position according to the second driving signal; and when the current position of the lens is higher than the target position, the lens is downwards adjusted to the target position according to the second driving signal.
The driving method comprises the following steps: controlling the first coil to push the lens to move according to the first driving signal, wherein the first magnetic field covers the first coil; controlling a second magnet to generate a second magnetic field, wherein the second magnet is fixedly arranged with the lens; and controlling a first tunnel magnetoresistive TMR element provided on the substrate to generate a second drive signal according to the detected second magnetic field, the second drive signal being used for adjusting the lens from a current position to a target position, the target position corresponding to the first drive signal. The voice coil motor provided by the application has high focusing accuracy and can meet the miniaturization requirement.
In one embodiment, as shown in fig. 7, the voice coil motor further includes an optical anti-shake assembly provided with a second TMR element and a second coil, and the method further includes: step 702 to step 704.
And step 702, controlling the second TMR element to acquire the offset of the lens at the target position according to the detected second magnetic field, and generating a third driving signal according to the offset.
Specifically, optical anti-shake element includes second TMR element and second coil, and the second TMR element sets up on the base plate, can establish on the same surface of base plate with first TMR element, and the second coil setting sets up with the camera lens is fixed, and first magnetic field covers the second coil. The second TMR element is capable of detecting a shift amount of the lens at the target position, such as a shake, a cut, and the like in the vertical direction and the horizontal direction. For example, when the lens is moved by being pushed by the first coil, the second TMR element detects a change in the second magnetic field, and the detected change in the magnetic field strength of the second magnetic field can identify the shift amount of the lens at the target position. The second TMR element may generate a third drive signal according to the offset amount, and transmit the third drive signal to the second coil. The second coil can push the lens to move to compensate the offset in the process of electrifying the third driving signal.
And 704, controlling the second coil to push the lens to move according to the third driving signal so as to compensate the offset.
In particular, the second coil is energized with the third drive signal, i.e. the second coil is able to compensate for the offset in dependence on the third drive signal. It should be noted that the second driving signal is used to coarsely adjust the lens to the target position in a first step, and the third driving signal is used to finely adjust the lens to the target position in a second step, where the first step is larger than the second step. The optical anti-shake component can reduce shake in the lens moving process, and accuracy and stability of the voice coil motor adjusting lens are improved.
In one embodiment, as shown in fig. 8, the third drive signal includes a first direction drive signal and a second direction drive signal, and the second TMR element includes: a first-direction TMR sensor and a second-direction TMR sensor, the step of controlling the second TMR element to acquire an offset amount of the lens at the target position in accordance with the detected second magnetic field, comprising: step 802 to step 804.
And step 802, controlling the first-direction TMR sensor to acquire the offset in the first direction in the lens moving process and generating a first-direction driving signal according to the offset in the first direction.
Specifically, the second TMR element may refer to a plurality of TMR sensors, and may detect a shake or tilt-generated offset in a plurality of directions. As the second TMR element includes: a first-direction TMR sensor and a second-direction TMR sensor. The first direction is perpendicular to the second direction, and when the first direction is a horizontal direction, the second direction is a vertical direction, and when the first direction is a vertical direction, the second direction is a horizontal direction. And the first direction TMR sensor is used for acquiring the offset in the first direction in the moving process of the lens, generating a first direction driving signal according to the offset in the first direction, and transmitting the first direction driving signal to the second coil so that the second coil pushes the lens to move according to the first direction driving signal, thereby compensating the offset of the lens in the first direction.
And step 804, controlling a second-direction TMR sensor to acquire the offset in the second direction in the lens moving process and generating a second-direction driving signal according to the offset in the second direction, wherein the first direction is perpendicular to the second direction.
Specifically, the second-direction TMR sensor can acquire an offset in the second direction in the moving process of the lens, generate a second-direction driving signal according to the offset in the second direction, and transmit the second-direction driving signal to the second coil, so that the second coil pushes the lens to move according to the second-direction driving signal, thereby compensating the offset of the lens in the second direction.
It should be understood that although the various steps in the flow charts of fig. 6-8 are shown in order as indicated by the arrows, the steps are not necessarily performed in order as indicated by the arrows. The steps are not performed in the exact order shown and described, and may be performed in other orders, unless explicitly stated otherwise. Also, at least some of the steps in fig. 6-8 may include multiple sub-steps or multiple stages that are not necessarily performed at the same time, but may be performed at different times, and the order of performance of the sub-steps or stages is not necessarily sequential, but may be performed in turn or alternating with other steps or at least some of the sub-steps or stages of other steps.
The implementation of each module in the voice coil motor provided in the embodiments of the present application may be in the form of a computer program. The computer program may be run on a terminal or a server. Program modules constituted by such computer programs may be stored on the memory of the electronic device. Which when executed by a processor, performs the steps of the method described in the embodiments of the present application.
The embodiment of the application also provides a computer readable storage medium. One or more non-transitory computer-readable storage media containing computer-executable instructions that, when executed by one or more processors, cause the processors to perform the steps of the method of driving.
A computer program product comprising instructions which, when run on a computer, cause the computer to perform a method of driving.
Any reference to memory, storage, database, or other medium used herein may include non-volatile and/or volatile memory. Non-volatile memory can include read-only memory (ROM), Programmable ROM (PROM), Electrically Programmable ROM (EPROM), Electrically Erasable Programmable ROM (EEPROM), or flash memory. Volatile memory can include Random Access Memory (RAM), which acts as external cache memory. By way of illustration and not limitation, RAM is available in a variety of forms, such as Static RAM (SRAM), Dynamic RAM (DRAM), Synchronous DRAM (SDRAM), double data rate SDRAM (DDR SDRAM), Enhanced SDRAM (ESDRAM), synchronous Link (Synchlink) DRAM (SLDRAM), Rambus Direct RAM (RDRAM), direct bus dynamic RAM (DRDRAM), and bus dynamic RAM (RDRAM).
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present application. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (14)
1. A voice coil motor for driving a lens to move, the voice coil motor comprising:
a substrate;
the first magnet is arranged on the substrate and used for generating a first magnetic field;
the first coil is fixedly arranged with the lens and used for pushing the lens to move according to a first driving signal, and the first magnetic field covers the first coil;
the second magnet is fixedly arranged with the lens and used for generating a second magnetic field;
a first tunnel magnetoresistive TMR element disposed on the substrate for generating a second drive signal according to the detected second magnetic field, the second drive signal being used for adjusting the lens from a current position to a target position in a first step to achieve focusing;
and the optical anti-shake component is used for generating a third driving signal according to the detected offset of the lens at the target position and compensating the offset according to the third driving signal, wherein the third driving signal is used for adjusting the lens to the target position in a second step, and the first step is larger than the second step.
2. The voice coil motor of claim 1, wherein the optical anti-shake assembly comprises:
a second TMR element provided on the substrate, for acquiring the offset according to the detected second magnetic field, and generating the third driving signal according to the offset;
and the second coil is fixedly arranged with the lens and is used for pushing the lens to move according to the third driving signal so as to compensate the offset.
3. The voice coil motor of claim 2, wherein the third drive signal comprises a first direction drive signal and a second direction drive signal, the second TMR element comprising:
a first direction TMR sensor for acquiring an offset of the lens in a first direction at the target position and generating the first direction driving signal according to the offset in the first direction;
and a second direction TMR sensor for acquiring an offset of the lens in a second direction at the target position and generating the second direction driving signal according to the offset in the second direction, wherein the first direction is perpendicular to the second direction.
4. The voice coil motor of claim 1, further comprising:
and the driving unit is arranged on the substrate, is connected with the first coil and the first tunnel magnetic resistance TMR element, is used for generating the first driving signal and transmitting the first driving signal to the first coil, and is also used for adjusting the lens from the current position to the target position according to the second driving signal.
5. The vcm according to claim 1, wherein the number of the first magnets is plural, and the plural first magnets are uniformly distributed outside the first coil.
6. The voice coil motor of claim 5, comprising four of the first magnets.
7. The vcm according to claim 1, wherein the first magnet and the first tunnel magnetoresistive TMR element are disposed on a side of the substrate facing the first coil.
8. The vcm according to claim 7, wherein a thickness of the first tunnel magnetoresistive TMR element is less than or equal to a thickness of the first magnet.
9. A driving method applied to the voice coil motor according to any one of claims 1 to 8, the voice coil motor being used for driving a lens to move, the method comprising:
controlling a first coil to push the lens to move according to a first driving signal, wherein a first magnetic field generated by a first magnet covers the first coil;
controlling a second magnet to generate a second magnetic field, wherein the second magnet is fixedly arranged with the lens;
controlling a first Tunnel Magnetoresistive (TMR) element provided on a substrate to generate a second drive signal for adjusting the lens from a current position to a target position in a first step in accordance with the detected second magnetic field;
and generating a third driving signal according to the detected offset of the lens at the target position, and compensating the offset according to the third driving signal, wherein the third driving signal is used for adjusting the lens to the target position in a second step, and the first step is larger than the second step.
10. The driving method according to claim 9, characterized in that the method further comprises:
controlling a second TMR element to acquire the offset of the lens at the target position according to the detected second magnetic field and generate a third driving signal according to the offset;
and controlling a second coil to push the lens to move according to the third driving signal so as to compensate the offset.
11. The driving method according to claim 10, wherein the third driving signal includes a first direction driving signal and a second direction driving signal, and the controlling the second TMR element to acquire an offset amount of the lens at the target position according to the detected second magnetic field includes:
controlling a first-direction TMR sensor to acquire the offset of the lens in a first direction at the target position and generate the first-direction driving signal according to the offset in the first direction;
and controlling a second-direction TMR sensor to acquire the offset of the lens in a second direction at the target position and generate the second-direction driving signal according to the offset in the second direction, wherein the first direction is perpendicular to the second direction.
12. The utility model provides a camera module which characterized in that includes:
a lens;
a voice coil motor as claimed in any one of claims 1 to 8, for driving lens movement.
13. A camera module comprising a memory, a processor and a voice coil motor, the memory having stored therein a computer program which, when executed by the processor, causes the processor to carry out the steps of the driving method according to any one of claims 9 to 11.
14. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, carries out the steps of the method of driving according to any one of claims 9-11.
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| CN115550630B (en) * | 2022-01-21 | 2023-06-13 | 荣耀终端有限公司 | System and method for detecting lens position, voice coil motor and equipment |
| CN114866669B (en) * | 2022-04-26 | 2024-06-07 | 杭州海康威视数字技术股份有限公司 | Video camera and voice coil motor driving method for video camera |
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