Shape Memory Alloy Camera Actuation for Low-Power OIS
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Solution Overview
Problem
Conventional voice coil motor (VCM) technology is difficult to apply to micro-scale camera devices requiring low power consumption and high performance, especially for autofocus and optical image stabilization, with challenges in detecting movement accuracy and temperature compensation, and ensuring reliable conductive connections.
Innovation Solution
A camera device utilizing a shape memory alloy member for movement detection and optical image stabilization, reducing power consumption by generating eight times greater driving force than electromagnetic force, and improving temperature compensation and conductive connection reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If voice coil motor (VCM) technology is used for autofocus and optical image stabilization, then driving force and speed are improved, but power consumption increases and application to micro-scale camera devices becomes difficult
Solution Approach 1:
The patent replaces the electromagnetic driving system (voice coil motor) with a shape memory alloy-based actuating system. The shape memory alloy member (45) transforms thermal energy into mechanical work through phase transition, eliminating the need for electromagnetic fields and coils, thereby reducing power consumption while providing sufficient driving force for micro-scale camera devices
Solution Approach 2:
The patent utilizes the phase transition property of shape memory alloy materials. When the shape memory alloy member (45) undergoes phase transition from austenite to martensite or vice versa, it exhibits large deformation capability, generating significant driving force for moving the OIS moving unit without requiring continuous electromagnetic power input
2Device complexity
If magnets are used for both autofocus and optical image stabilization, then device downsizing is achieved, but magnetic field interference with peripheral elements increases
Solution Approach 1:
The patent replaces the magnetic field-based driving system with a thermal-mechanical actuation system using shape memory alloys. This substitution eliminates magnetic field generation entirely, removing the source of magnetic interference with peripheral elements while still achieving compact device integration through the inherent flexibility of the shape memory alloy member
Solution Approach 2:
The patent converts the typically harmful magnetic field interference into a beneficial feature by completely eliminating magnets from the system. The shape memory alloy actuation system provides a non-magnetic alternative that not only removes interference but also enables closer integration with sensitive peripheral elements in compact camera devices
3Ease of manufacture
If conventional conductive connections are used between shape memory alloy member and circuit board, then manufacturing is simplified, but connection reliability deteriorates due to thermal expansion differences
Solution Approach 1:
The patent modifies the thermal parameters of the connection system by introducing an elastic member with thermal expansion characteristics that bridge the gap between the shape memory alloy member and circuit board. This elastic member accommodates thermal expansion differences through its own deformation, maintaining reliable electrical connection while allowing manufacturing to proceed with conventional methods
Solution Approach 2:
The patent introduces an elastic member as an intermediary component between the shape memory alloy member and the circuit board. This intermediary absorbs thermal stress and maintains electrical connectivity by flexing to accommodate differential thermal expansion, thereby ensuring connection reliability without complicating the manufacturing process
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
Accurately detects movement in X-axis, Y-axis, and rolling angles with reduced power consumption, minimizes magnetic interference, and facilitates smaller product design, enabling dual or triple camera devices with increased battery runtime and improved reliability.
Implementation Method 1
an elastic member, which is connected to the fixed unit and the OIS moving unit and supports the OIS moving unit with respect to the fixed unit; and a shape memory alloy member, which interconnects the OIS moving unit and causes the OIS moving unit to move in a direction perpendicular to the optical axis
Implementation Method 2
first to third sensors, which are disposed on the fixed unit or the OIS moving unit and sense a position of the OIS moving unit, thereby generating first to third sensing voltages
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
One embodiment comprises: a fixing part; a moving part including a substrate part arranged to be spaced from the fixing part, and an image sensor arranged on the substrate part; a shape memory alloy member which is coupled to the fixing part and the moving part, and which is electrically connected to the substrate part; a location sensing unit including first, second and third sensors arranged on the substrate part; and a control unit which supplies a driving signal to the shape memory alloy member, and which moves the moving part in the direction that is perpendicular to the optical axis or rotates the moving part around the optical axis by means of the shape memory alloy member.