Thermo-Mechanical Stabilization of Nitinol Wires in OIS Suspension

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Solution Overview

Problem

Current methods for stabilizing shape memory alloy (SMA) wires in camera lens suspensions are inefficient and require complex equipment, as they rely on electrical burn-in processes that are time-consuming and not fully effective in achieving consistent and accurate performance.

Innovation Solution

A thermo-mechanical stabilization process that cyclically strains and de-strains SMA wires by moving the suspension sections relative to each other while applying heat, causing the wires to transition between austenite and martensite phases, optimizing stabilization results and minimizing damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electrical burn-in stabilization process is used, then wire resistance and stroke can be stabilized, but the process becomes time-consuming and requires complex equipment

Engineering Contradiction:
Improvewire resistance stabilityVSAvoidstabilization time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent changes the stabilization parameters from electrical (electrical burn-in) to thermal and mechanical (thermal soaking at 85°C combined with mechanical cycling). This parameter transformation achieves the same stabilization effect on wire resistance and stroke while reducing process complexity and time requirements

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the electrical stabilization system with a thermal-mechanical system. Instead of using electrical currents to stabilize the wires, the invention uses controlled heating combined with mechanical straining and unstraining cycles to achieve stabilization, thereby eliminating complex electrical equipment

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If electrical burn-in stabilization process is used, then wire characteristics can be stabilized, but the equipment complexity increases

Engineering Contradiction:
Improvesuspension operation consistencyVSAvoidstabilization equipment complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent substitutes complex electrical stabilization equipment with simpler thermal-mechanical equipment. The stabilization is achieved through thermal soaking combined with mechanical cycling of the suspension system, eliminating the need for specialized electrical burn-in equipment

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent makes the stabilization process multi-functional by combining thermal treatment (soaking at 85°C) with mechanical cycling in a single integrated process. This universal approach simultaneously stabilizes wire resistance, stroke, and mechanical properties without requiring separate specialized equipment for each function

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Manufacturing precision

If more stabilization cycles are applied, then calibration accuracy improves, but manufacturing time increases

Engineering Contradiction:
Improvecalibration accuracyVSAvoidmanufacturing throughput
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent optimizes the stabilization parameters (thermal temperature of 85°C combined with mechanical cycling frequency and amplitude) to achieve maximum calibration accuracy in minimum time. The optimized parameter combination provides rapid stabilization without sacrificing precision

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs periodic mechanical cycling (straining and unstraining cycles) combined with continuous thermal soaking. This periodic mechanical action, when optimally frequency-modulated, achieves rapid stabilization of wire characteristics while maintaining high calibration accuracy and enabling faster manufacturing throughput

Inventive Principle:
Principle #19Periodic action

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

This approach reduces equipment complexity, allows for longer stabilization times, and enhances product stiffness, achieving equivalent or better results than traditional electrical burn-in methods with fewer cycles and less asymmetry, while maintaining calibrated resistance properties.

Implementation Method 1

the temperature, strain, and de-strain levels are configured to cause the wires to cyclically transition between austenite and martensite phases during the mechanical straining and de-straining

Methodology Applied
Scientific EffectPhase transition: Phase Change

Implementation Method 2

Heat is applied to the wires while mechanically straining and de-straining the wires

Methodology Applied
Scientific EffectThermal heating: Heating

Data Source

PatentEP3356566B1Thermo-mechanical stabilization of nitinol wires in an optical image stabilization suspension
Publication Date: 2022.09.21 HUTCHINSON TECH INC
  • EP3356566B1 patent drawingFigure 1
  • EP3356566B1 patent drawingFigure 2
  • EP3356566B1 patent drawingFigure 3

AI summary

A method and system for stabilizing properties of shape memory alloy (SMA) wires in an optical image stabilization (OIS) suspension of the type having a first or support assembly and a second or moving assembly coupled with respect to one another by the SMA wires. Embodiments of the method comprise cyclically mechanically straining and de-straining the wires by moving the moving and support assemblies with respect to one another while heat is applied to the wires. The temperature, strain, and de-strain levels are configured to cause the wires to cyclically transition between austenite and martensite phases during the mechanical straining and de-straining.