Shape Memory Polymer Wearable Fit Customization

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Solution Overview

Problem

Existing wearable devices are not customizable to fit individual anatomical features, leading to comfort issues and limitations in sharing between multiple users.

Innovation Solution

The use of thermoset shape memory polymers in wearable devices allows for reversible customization by manipulating the shape of the device above its glass transition temperature and locking it in below that temperature.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If standard sizes are used for wearable devices, then manufacturing cost is reduced and production is simplified, but comfort and fit for individual users deteriorate

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidindividual fit
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The wearable device incorporates a shape memory polymer that can dynamically change its shape between a standardized manufactured form and a customized fitted form. The polymer transitions from a first shape (standard) to a second shape (customized) when exposed to body heat, allowing the device to adapt to individual user anatomy while maintaining simple standard manufacturing processes

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The shape memory polymer undergoes a parameter change in its physical state based on temperature. When the device is worn, body heat raises the polymer's temperature above its glass transition temperature, causing it to transition from a rigid standardized shape to a flexible customized shape that conforms to the user's anatomy, thereby achieving individual fit from standard manufacturing

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If custom-fitted products are made using thermoplastics in softened state, then individual fit is improved, but temperature stability and cosmetic appearance deteriorate

Engineering Contradiction:
Improvecustom fitVSAvoidtemperature stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent uses a shape memory polymer that combines the benefits of thermoplastics (customizability through heat) with the advantages of thermosets (temperature stability and cosmetic appearance). The polymer maintains its structural integrity and aesthetic properties at body temperatures while still allowing for reversible shape changes, overcoming the limitations of conventional thermoplastics

Inventive Principle:
Principle #40Composite materials

3Adaptability or versatility

If UV-curable silicones with catalyst and curative are used for customization, then custom fit is achieved, but the materials cure even in absence of UV and provide only single non-reversible impression

Engineering Contradiction:
Improvecustomization capabilityVSAvoidrepeatability
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The shape memory polymer enables periodic and reversible shape changes rather than a single non-reversible curing process. The device can transition between its standardized shape and customized shape multiple times by repeatedly exposing it to body heat, allowing users to retry customization if needed and enabling multiple users to share the same device by resetting it to its original shape

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent utilizes the phase transition properties of shape memory polymers, which undergo a reversible transition between a glassy state (at lower temperatures) and a rubbery state (at elevated temperatures). This phase transition allows the material to be deformed into a custom shape when heated by the body, then return to its original shape when cooled, providing repeatable customization without permanent chemical curing

Inventive Principle:
Principle #36Phase transitions

4Reliability

If shape memory alloys are used, then shape memory effect is achieved, but density and processing pressure requirements increase

Engineering Contradiction:
Improveshape memory effectVSAvoiddevice density
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent employs shape memory polymers as a lighter, more cost-effective alternative to shape memory alloys. While polymers may have slightly different performance characteristics, they provide sufficient shape memory functionality for wearable applications while significantly reducing weight and manufacturing complexity, making the technology more accessible and comfortable for extended wear

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 solution provides customizable wearable devices that are comfortable, stable, and can be easily shared among multiple users, as they can be repeatedly customized and revert to their original shape without melting.

Implementation Method 1

thermoset shape memory polymers do not melt and can reversibly transition between customized shapes and their original molded forms

Methodology Applied
Scientific EffectShape memory polymer effect: Shape Memory Polymer

Implementation Method 2

manipulating the shape of the device above its glass transition temperature and locking it in below that temperature

Methodology Applied
Scientific EffectGlass transition: Phase Change

Data Source

PatentEP3844200B1Wearable devices using shape memory polymers
Publication Date: 2025.02.12 BOSE CORP
  • EP3844200B1 patent drawingFigure 1A~1B
  • EP3844200B1 patent drawingFigure 1C
  • EP3844200B1 patent drawingFigure 2

AI summary

A wearable device including a body having one or more embedded electronic components, the body further including a thermoset material having a polymeric backbone with at least one urethane linkage and a glass transition temperature. At a first temperature that is lower than the glass transition temperature, the body has an original shape. When the body is heated to a second temperature that is higher than the glass transition temperature, the body is deformable from the original shape to a first shape and when the body is cooled to a third temperature that is lower than the glass transition temperature, the first shape is maintained. The body is further configured to transition from the first shape to the original shape when the body is heated from the third temperature to a fourth temperature that is higher than the glass transition temperature.