Shape Memory Alloy Bimorph Actuators for Low-Profile Motion
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Solution Overview
Problem
Existing shape memory alloy (SMA) systems for camera lens actuators are bulky and require a large footprint, limiting their Z-stroke range and compactness.
Innovation Solution
The development of SMA actuators with compact footprints and high Z-stroke capabilities, utilizing SMA buckle and bimorph actuators, which include features like buckle arms and bimorph actuators with improved electrical connections and materials to enhance actuation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional SMA systems with multiple components (bearing, flexure element, balls) are used, then the system provides reliable actuation, but the system becomes bulky with large footprint and height clearance
Solution Approach 1:
The patent combines multiple separate components (bearing, flexure element, balls) into an integrated SMA actuator structure. The buckle arms and SMA wires are merged into a unified assembly that eliminates the need for separate support assemblies and reduction gears, achieving both reliability and compactness.
Solution Approach 2:
The SMA wires serve multiple functions simultaneously: they provide actuation force, structural support, and positioning. The buckle arms perform both mechanical linkage and actuation functions, eliminating the need for dedicated separate components for each function.
2Stability of the object's composition
If traditional SMA systems with multiple components are used, then the system provides stable operation, but the system requires large height clearance
Solution Approach 1:
The actuator components are arranged in a nested configuration where the SMA wires are positioned within the structural framework of the buckle arms. This nesting allows the actuator to achieve stable operation with minimal height clearance by utilizing the internal space of the existing structure.
3Device complexity
If SMA wires are directly attached to support assembly and moving assembly, then the actuation is simple, but the Z-stroke range is limited
Solution Approach 1:
The buckle arms are designed to dynamically change their configuration during actuation, transitioning between buckled and unbuckled states. This dynamic behavior amplifies the small displacement from SMA wire contraction into a larger Z-stroke range while maintaining simple direct attachment of the SMA wires.
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 actuators achieve a Z-stroke greater than 0.4 millimeters with a height of 2.2 millimeters or less, providing a small footprint suitable for applications such as autofocus, micro-fluidic pumps, and optical image stabilization, while maintaining precise control and reduced hysteresis.
Implementation Method 1
The SMA actuator includes an SMA wire 100... The SMA wire 100 is actuated by applying electrical drive signals to the SMA wire
Implementation Method 2
Each of the SMA wires has one end attached to the support assembly, and an opposite end attached to the moving assembly. The suspension is actuated by applying electrical drive signals to the SMA wires
Implementation Method 3
at least one bimorph actuator including a shape memory alloy material
Implementation Method 4
The bimorph actuator attached to the base
Data Source
AI summary
SMA actuators and related methods are described. One embodiment of an actuator includes a base; a plurality of buckle arms; and at least a first shape memory alloy wire coupled with a pair of buckle arms of the plurality of buckle arms. Another embodiment of an actuator includes a base and at least one bimorph actuator including a shape memory alloy material. The bimorph actuator attached to the base.