Optical Element SMA Position Sensing for Compact Image Stabilization
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Solution Overview
Problem
Modern electronic devices with image-capturing and video-recording functions face challenges in reducing the size of optical element driving mechanisms while maintaining durability and efficiency for auto focus and optical image stabilization.
Innovation Solution
A driving mechanism utilizing a shape memory alloy (SMA) with a control assembly and position sensing assembly, which includes multiple driving units and sensors to control the movement of an optical assembly in different dimensions, allowing for precise positioning and stabilization using various control modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional driving mechanisms are used for optical elements, then reliable auto focus and optical image stabilization can be achieved, but the size of the device increases and durability decreases
Solution Approach 1:
The patent replaces traditional mechanical driving mechanisms (motors, gears, linkages) with a shape memory alloy-based driving system. The shape memory alloy elements undergo phase transformation under electrical stimulation to produce mechanical motion, eliminating complex mechanical components while achieving reliable optical element positioning and stabilization.
Solution Approach 2:
The patent utilizes the phase transformation temperature parameter of shape memory alloy as the controlling parameter. By applying electrical current to heat the shape memory alloy above its transformation temperature, the material changes from martensite to austenite phase, producing controlled mechanical deformation that drives the optical element without requiring large mechanical actuators.
2Force
If traditional driving mechanisms are used for optical elements, then sufficient driving force can be provided, but the device becomes more complex and less durable
Solution Approach 1:
The patent substitutes mechanical force transmission systems with shape memory alloy elements that generate force directly through phase transformation. The shape memory alloy elements can produce sufficient driving force for optical element movement and stabilization without requiring motors, gear trains, or other complex mechanical force transmission components.
Solution Approach 2:
The patent employs shape memory alloy, a composite material exhibiting both metallic properties and memory effect, to create a multifunctional driving element that combines actuation, force generation, and positioning capabilities in a single component, thereby reducing overall system complexity while maintaining adequate driving force.
3Volume of moving object
If shape memory alloy is used for driving, then the device size is reduced, but control precision may be affected
Solution Approach 1:
The patent incorporates feedback mechanisms to monitor the position and state of optical elements driven by shape memory alloy. By continuously sensing the actual position and comparing it with the target position, the control system can adjust electrical stimulation parameters to compensate for hysteresis and nonlinearity in shape memory alloy response, thereby achieving precise control despite the compact size.
Solution Approach 2:
The patent applies preliminary electrical stimulation to shape memory alloy elements to pre-position optical elements before main operation begins. This preliminary action allows the system to establish accurate initial positions and calibration parameters, improving subsequent control precision while maintaining the compact advantages of shape memory alloy actuation.
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 solution enables miniaturization of the driving mechanism, enhances control accuracy, and improves durability by using SMA units and sensors to manage the movement of optical elements effectively, ensuring efficient auto focus and optical image stabilization.
Implementation Method 1
The driving assembly includes a shape memory alloy. The first driving unit is used for driving the movable portion to move relative to the fixed portion, and the material of the first driving unit includes shape memory alloy
Implementation Method 2
The first position sensor is used for detecting the movement of the movable portion relative to the fixed portion in a first dimension. The first reference element corresponds to the first position sensor, and the first reference element includes a first magnetic unit
Data Source
AI summary
A driving mechanism is provided. The driving mechanism includes a fixed portion, a movable portion movable relative to the fixed portion, a driving assembly used for driving the movable portion to move relative to the fixed portion, and a position sensing assembly for detecting the movement of the movable portion relative to the fixed portion. The driving assembly drives the movable portion by a control signal provided by a control assembly, and the driving assembly includes shape memory alloy. The control assembly receives a position signal provided by the position sensing assembly. The movable portion vibrates relative to the fixed portion at a frequency that is lower than a maximum frequency, and the maximum frequency is less than 10000 Hz.