SMA Wire Camera Module Actuator for EMI Reduction
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Solution Overview
Problem
Existing camera modules in mobile devices face challenges with electromagnetic interference from voice coil motors, leading to complex structures and reduced performance, especially when capturing images with high zoom magnification, and require a compact driving unit that avoids interference while providing stable image capture.
Innovation Solution
A camera module utilizing shape memory alloy (SMA) wires to drive the optical module's rotation about multiple axes, using SMA wires that change length in response to current, allowing for compact and interference-free operation by rotating the optical module with respect to the optical axis and perpendicular axes, thus enabling a 3-axis gimbal function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a voice coil motor is used as a driving unit for rotating the camera module, then the camera module can be driven to rotate, but electromagnetic interference is generated that negatively affects the performance of nearby electronic components
Solution Approach 1:
The patent replaces the voice coil motor (electromagnetic actuator) with a shape memory alloy-based actuator that uses thermal expansion to drive the camera module rotation. This substitution eliminates electromagnetic interference while maintaining the driving function, as the SMA wire transforms electrical energy to mechanical energy through phase change and thermal expansion rather than electromagnetic fields.
Solution Approach 2:
The patent utilizes the phase change parameter of shape memory alloy materials to generate driving force. By controlling the temperature of the SMA wire through electrical heating, the material transitions between martensitic and austenitic phases, causing dimensional changes that drive the camera module rotation. This parameter-based approach replaces electromagnetic fields with thermal parameters.
2Object-generated harmful factors
If a shielding structure or rearrangement is used to solve electromagnetic interference, then the harmful effects are reduced, but the structure becomes more complicated
Solution Approach 1:
Instead of adding shielding structures or rearranging components to mitigate electromagnetic interference, the patent fundamentally replaces the electromagnetic actuator with a thermal-based actuator. This eliminates the source of interference rather than addressing it through additional structural complexity.
3Measurement precision
If the camera module is designed for high zoom magnification, then the performance is improved, but the requirements for stable image capture and compact driving unit increase
Solution Approach 1:
The patent employs a compact SMA-based actuator that integrates directly into the camera module housing, eliminating the need for separate, complex driving units. The SMA wire can be directly mounted to rotate the optical module, providing a space-efficient solution that supports high zoom functionality without adding structural complexity.
Solution Approach 2:
The SMA actuator is integrated within the existing camera module housing structure, nesting the driving mechanism within the overall assembly. This nested configuration allows the driving unit to occupy minimal space while providing the necessary rotational capability for high zoom magnification.
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
The SMA-based camera module achieves stable image capture with reduced electromagnetic interference, providing a compact and efficient driving mechanism that supports high zoom magnification without increasing the complexity of the driving unit, ensuring accurate and stable image recording.
Implementation Method 1
a driving unit configured to rotate the optical module about an optical axis and an axis perpendicular to the optical axis. The driving unit may include an actuator including at least one shape memory alloy (SMA) wire configured to change in length in response to applied current
Implementation Method 2
A temperature of the SMA material may be changed by causing an electric current to pass through the SMA material to heat the SMA material to cause a phase change
Implementation Method 3
controlling a temperature of the SMA material over an active temperature range in which the SMA material changes between martensitic and austenitic phases in which stress and strain of the SMA material change
Data Source
AI summary
A camera module includes: a first driving unit including a rotating plate disposed in a housing so as to be rotatable about an optical axis, and a first shape memory alloy (SMA) wire configured to rotate the rotating plate in response to a first applied current; and an optical module disposed in the housing and coupled to the rotating plate.