SMA Camera Actuator Bearing Converts Lateral Force to Tilt
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Solution Overview
Problem
Existing camera actuator assemblies for optical image stabilization using shape-memory alloy (SMA) wires face challenges in miniaturization and efficient movement mechanisms, particularly in providing tilting motions without applying net torque in orthogonal directions.
Innovation Solution
An actuator assembly comprising four lengths of shape memory alloy wires connected between a first and a second part, with a bearing arrangement that converts lateral forces into tilting motions about non-parallel axes, allowing independent control of each wire section for precise movement and torque generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If four SMA actuator wires are used to move the lens assembly in orthogonal directions, then optical image stabilization is achieved, but net torque is applied to the lens assembly in the plane of orthogonal directions
Solution Approach 1:
A bearing arrangement is introduced as an intermediary mechanism between the SMA actuator wires and the lens assembly. The bearing converts lateral forces from the SMA wires into pure tilting motions, mediating the force transmission to eliminate net torque application to the lens assembly while maintaining stabilization functionality.
Solution Approach 2:
The system changes the parameter of force application by using non-collinear SMA wire arrangements and bearing mechanisms to transform direct lateral forces into controlled tilting motions. This parameter change allows achieving the same stabilization effect without the harmful net torque component.
2Volume of moving object
If the camera module is miniaturized for portable devices, then device size is reduced, but the complexity of achieving precise tilting motion without net torque increases
Solution Approach 1:
The bearing arrangement merges multiple functions into a single component: it supports the lens assembly, enables tilting motion, and converts lateral forces into pure rotation. This consolidation achieves precise control without net torque while maintaining compact dimensions suitable for miniaturized cameras.
Solution Approach 2:
The system uses non-collinear SMA wire arrangements that operate in multiple spatial dimensions to achieve tilting motion. By utilizing three-dimensional wire routing and bearing geometry, the system achieves precise control in a compact volume, effectively using dimensional space to reduce overall device size while maintaining functionality.
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
Enables efficient optical image stabilization and miniaturization by allowing tilting of the lens assembly without applying net torque in the plane of orthogonal directions, enhancing the camera's ability to stabilize images and focus.
Implementation Method 1
four lengths of shape memory alloy wire which are connected (or 'coupled') between the second part and the first part
Implementation Method 2
actuator assembly comprising four lengths of shape memory alloy wires
Implementation Method 3
The bearing arrangement is configured to convert lateral force(s) normal to the primary axis generated by the drive arrangement into tilting of the second part about the first and/or second axes
Data Source
AI summary
A camera assembly is disclosed. The camera assembly comprises: a first part; a second part tiltable with respect to the first part, the second part including an image sensor and a lens system, wherein the lens system is above the image sensor with respect to a primary axis passing through the image sensor; a drive system configured, in response to drive signals, to cause tilting of the second part with respect to the first part, wherein the tilting is about first and/or second axes which are not parallel and which are perpendicular to the primary axis; and one or more flexible connectors operatively connected to the second part, wherein the one or more flexible connectors are routed to pass between the second part and the first part below the image sensor with respect to the primary axis.