Camera Assembly Using SMA Actuator Wires for Optical Image Stabilization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing camera assemblies face challenges in miniaturizing optical image stabilization (OIS) systems due to the difficulty in integrating OIS actuators within the tight packaging of miniature camera components.
Innovation Solution
The camera assembly employs plural shape memory alloy (SMA) actuator wires to provide relative movement between the image sensor and the lens assembly, allowing for optical image stabilization. This design moves the image sensor laterally, rather than the lens assembly, facilitating miniaturization and improving stabilization performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If OIS actuators are integrated into the camera assembly, then optical image stabilization is achieved, but the device size increases and miniaturization becomes difficult
Solution Approach 1:
The patent merges the OIS actuator function with the existing lens assembly structure. The actuator is integrated within the lens barrel, utilizing the same space that would otherwise be occupied by lens elements and mounting structures. This consolidation allows the camera module to achieve optical image stabilization without increasing the overall device volume, as the stabilization mechanism shares the optical path space rather than adding a separate stabilization subsystem.
Solution Approach 2:
The actuator mechanism is nested within the lens assembly structure. The patent describes an actuator that is positioned inside the lens barrel, with its moving components nested within the optical element mounting structure. This nested arrangement allows the stabilization mechanism to occupy the same physical envelope as the optical system, enabling miniaturization while maintaining full OIS functionality.
2Reliability
If the lens assembly is moved for OIS, then stabilization is achieved, but the clearance required increases the package size
Solution Approach 1:
Instead of moving the lens assembly along the optical axis to achieve stabilization, the patent inverts the approach by moving the image sensor laterally perpendicular to the optical axis. This inversion of the stabilization mechanism fundamentally changes the direction of movement required, allowing the use of compact lateral displacement structures rather than requiring extensive axial clearance for lens movement.
Solution Approach 2:
The patent transitions from one-dimensional axial movement of the lens to two-dimensional lateral movement of the image sensor. By moving the sensor in the lateral dimension rather than along the optical axis, the system achieves stabilization without requiring the large axial clearance that would be needed for lens-based OIS, thereby reducing the overall package length.
3Volume of moving object
If SMA actuator wires are used, then miniaturization is achieved, but the ability to move the image sensor laterally is limited
Solution Approach 1:
The patent employs shape memory alloy (SMA) actuator wires that utilize phase transformation parameter changes to generate actuation force. The SMA wires transform from austenite to martensite phase upon heating, causing significant length change that enables lateral movement of the image sensor. This parameter-based actuation mechanism provides sufficient stroke length for OIS within a miniaturized form factor, overcoming the limitation of small displacement typically associated with微型 actuators.
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 use of SMA actuator wires enables effective miniaturization of the camera assembly while providing improved optical image stabilization, including rotational stabilization, by allowing lateral movement and rotation of the image sensor.
Implementation Method 1
plural shape memory alloy actuator wires in an arrangement capable, on selective driving thereof, of moving the image sensor relative to the support structure in any direction laterally to the light-sensitive region of the image sensor
Data Source
AI summary
A camera assembly comprises a support structure and an image sensor mounted on a carrier that is suspended on the support structure by at least one plain bearing that allows movement of the carrier and the image sensor relative to the support structure in any direction laterally to the light-sensitive region of the image sensor. An actuator arrangement comprising plural shape memory alloy wires is arranged to move the carrier and the image sensor relative to the support structure for providing optical image stabilisation of the image captured by the image sensor.