Anti-Shake Motor Capacitive Position Sensing for Closed-Loop Control
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Solution Overview
Problem
The existing anti-shake motor designs for camera modules consume excessive internal space due to the need for Hall sensors or drive ICs with Hall detection capabilities, which limits the motor's size and drive force, and are prone to external magnetic interference and temperature fluctuations.
Innovation Solution
An anti-shake motor design that uses conductive electrode plates integrated into the circuit board to form a capacitor with magnetic components, generating capacitance signals for position detection, thereby optimizing internal space and reducing component count while minimizing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Hall sensors or drive ICs with Hall detection capabilities are incorporated into the anti-shake motor, then closed-loop control is achieved, but internal space is consumed and drive force is restricted
Solution Approach 1:
The patent merges the sensing magnet function into the existing magnetic component that drives the anti-shake bracket, eliminating the need for separate Hall sensors. The magnetic component serves dual purposes: generating driving force through electromagnetic interaction with coils and generating capacitance signals for position detection when combined with conductive electrode plates on the circuit board.
Solution Approach 2:
The magnetic component is designed to perform multiple functions: it interacts with coils to generate electromagnetic force for driving the bracket, and simultaneously forms a capacitor with conductive electrode plates to enable position sensing. This multi-functionality reduces component count and internal space requirements while maintaining closed-loop control capability.
2Reliability
If Hall sensors are used for position detection, then closed-loop control is implemented, but the system becomes susceptible to external magnetic interference and temperature fluctuations
Solution Approach 1:
The patent replaces the Hall effect-based magnetic field detection system with a capacitance-based detection system. Instead of using Hall sensors that detect magnetic field changes, the system uses conductive electrode plates forming capacitors with magnetic components, where position is detected through capacitance signal changes. This substitution eliminates susceptibility to external magnetic interference and reduces temperature sensitivity.
Solution Approach 2:
The detection mechanism changes from measuring magnetic field parameters (Hall effect) to measuring electrical capacitance parameters. By detecting changes in capacitance between conductive electrode plates and magnetic components as the bracket moves, the system achieves position detection that is insensitive to external magnetic fields and less affected by temperature variations.
3Measurement precision
If additional sensing components are added for closed-loop control, then position detection capability is improved, but device complexity increases
Solution Approach 1:
The patent combines position sensing functionality with existing structural components. The magnetic components that are already present for electromagnetic driving are also used as one element of the capacitor for position sensing, while conductive electrode plates are integrated into the circuit board. This merging eliminates the need for separate sensing magnets and Hall sensors, reducing component count while maintaining position detection precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enables accurate position detection of the anti-shake bracket, reduces internal space usage, and ensures sufficient driving force, improving the precision and efficiency of closed-loop control while avoiding issues associated with Hall detection.
Implementation Method 1
The conductive electrode plate, situated on the circuit board, forms a capacitor with the magnetic component. The magnetic component is electrically connected to the circuit board, which outputs the capacitance signal generated by the interaction between the magnetic component and the conductive electrode plate.
Implementation Method 2
The circuit board, also mounted on the base, features a coil designed to drive the magnetic component, thereby enabling the movement of the anti-shake bracket within the predetermined plane.
Data Source
AI summary
The present application discloses an anti-shake motor, a camera module, and electronic equipment. The anti-shake motor includes a base, an anti-shake bracket, a circuit board, and a conductive electrode plate. The anti-shake bracket is movably set on the base within a predetermined plane and has a conductive magnetic component. The circuit board is set on the base with a coil that drives the magnetic component to move the anti-shake bracket within the predetermined plane. The conductive electrode plate is set on the circuit board, forming a capacitor with the magnetic component, which is electrically connected to the circuit board to output the capacitive signal formed with the conductive electrode plate. The anti-shake motor, camera module, and electronic equipment provided in this embodiment can achieve closed-loop control of the anti-shake motor while minimizing internal space occupation.