SMA Actuator Buckle Arms for Compact Camera Autofocus
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Solution Overview
Problem
Shape memory alloy (SMA) systems for auto-focusing drives in camera lenses face challenges with complexity, resulting in bulky designs and limited Z-stroke range with a compact footprint.
Innovation Solution
The development of SMA actuators incorporating buckle and bimorph actuators with SMA wires, which provide a compact footprint and high Z-stroke range by using buckle arms and bimorph structures to achieve dynamic tilt and movement, enabling two-axis camera module OIS tilt and autofocus capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional SMA systems with moving assembly, bearing, and flexure elements are used, then the system provides support and movement capability, but the system becomes bulky with large footprint and height clearance requirements
Solution Approach 1:
The patent removes traditional mechanical components such as bearings, flexure elements, and complex support assemblies. Instead, it uses only SMA wires directly coupled to a compact base to achieve movement, extracting unnecessary components that contributed to bulkiness while maintaining the essential movement function
Solution Approach 2:
The patent combines the functions of support, movement, and actuation into a single integrated structure where SMA wires are directly coupled to a compact base. This merging eliminates the need for separate bearing assemblies, flexure elements, and support structures, resulting in a compact design with reduced footprint
2Strength
If traditional SMA systems with multiple components are used, then the system provides structural support, but the height clearance increases
Solution Approach 1:
The patent removes traditional mechanical support components such as bearing assemblies, flexure elements, and intermediate support structures. The structural support function is achieved through the direct coupling of SMA wires to a compact base, eliminating components that increased height clearance
Solution Approach 2:
Instead of using complex mechanical structures to provide support and then reducing height, the patent inverts the approach by using a simple compact base with directly coupled SMA wires. This inversion achieves structural support with minimal height clearance from the start
3Area of stationary object
If traditional SMA systems are used, then the system provides basic actuation, but the Z-stroke range is limited with compact footprint
Solution Approach 1:
The patent employs dynamic buckle arms that can change their structural configuration during actuation. These buckle arms allow the system to achieve extended Z-stroke range by dynamically adjusting their geometry, enabling larger displacement within a compact footprint without requiring additional space
Solution Approach 2:
The patent changes the structural parameters of the buckle arms, allowing them to transition between different configurations. This parameter change enables the system to achieve variable Z-stroke ranges while maintaining a compact footprint, as the buckle arms can adapt their geometry to maximize displacement in the limited space
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 mm with a height of 2.2 mm or less, offering a compact footprint suitable for camera lenses, enhancing autofocus and image stabilization while reducing bulkiness and increasing tilt angles up to ±5 degrees.
Implementation Method 1
The SMA actuator includes an SMA wire 100 configured to move the lens carriage 104 in the z-direction 105. The SMA actuator may be configured to move the lens carriage 104 in the z-direction 105 by heating and/or cooling the SMA wire 100.
Implementation Method 2
Shape memory alloy actuators and methods thereof
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.