Stretchable Substrate With Temperature-Tuned Stiffness Regions

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Solution Overview

Problem

Existing stretchable or flexible display devices face issues with structural instability at material boundaries due to varying stiffness, leading to potential device damage or detachment, and require complex manufacturing processes and wiring configurations.

Innovation Solution

A stretchable substrate with self-regulated stiffness distribution, featuring stiffness-maintenance and stiffness-variable regions, allows selective stretching by controlling temperature, maintaining structural stability and simplifying manufacturing and wiring through materials like PDMS and polyimide, and utilizing UV light or thermal methods to define different glass transition temperatures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the entire substrate is stretched, then flexibility is improved, but device damage or detachment occurs due to increased stiffness

Engineering Contradiction:
ImproveflexibilityVSAvoiddevice stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The substrate is divided into different regions with distinct mechanical properties: a first region with high elastic modulus for device mounting that maintains stiffness, and a second region with low elastic modulus that provides flexibility and stretchability. This local differentiation allows the substrate to be stretched without damaging devices mounted on the stiff region.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If different materials are used to vary stiffness in different regions, then region-selective elongation is achieved, but structural stability at boundary portions deteriorates

Engineering Contradiction:
Improvestiffness distributionVSAvoidboundary stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent uses materials with different elastic moduli to create regions with varying stiffness characteristics. The first material has a high elastic modulus for maintaining stiffness in device mounting regions, while the second material has a low elastic modulus for providing flexibility in stretchable regions, achieving stable stiffness distribution across boundaries.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If structural local stiffness variation is implemented by altering local dimensions or shapes, then stiffness control is improved, but manufacturing complexity and wiring complexity increase

Engineering Contradiction:
Improvestiffness controlVSAvoidmanufacturing process complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements stiffness variation by selecting materials with different elastic moduli for different regions, rather than altering local dimensions or shapes. This approach achieves the desired stiffness distribution while maintaining simpler manufacturing processes and wiring configurations compared to geometric modification methods.

Inventive Principle:
Principle #3Local quality

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 substrate maintains stable device connections and structural integrity while enabling region-selective elongation, minimizing deformation, and simplifying manufacturing processes and circuit wiring, thus enhancing electrical stability and reliability.

Implementation Method 1

the stiffness-variable portion may be deformed so as to become stretchable by having a stiffness lower than the predetermined stiffness when the predetermined temperature is exceeded

Methodology Applied
Scientific EffectGlass transition: Phase Change

Implementation Method 2

providing ultraviolet light from an upper side of the mask such that only the stiffness-maintenance portion is irradiated with the ultraviolet light

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Data Source

PatentEP4712706A1Stretchable substrate having self-stiffness distribution, manufacturing method therefor, and stiffness distribution varying method therefor
Publication Date: 2026.03.18 KOREA INST OF MACHINERY & MATERIALS
  • EP4712706A1 patent drawingFigure 1
  • EP4712706A1 patent drawingFigure 2
  • EP4712706A1 patent drawingFigure 3a

AI summary

A stretchable substrate having a self-controlled stiffness distribution includes a stiffness-maintaining region and a stiffness-variable region that are partitioned into different areas. The stretchable substrate includes a configuration in which the stiffness-maintaining region and the stiffness-variable region maintain a predetermined stiffness only at a temperature equal to or lower than a predetermined temperature. The stiffness-variable region includes a structure in which, only at a temperature equal to or higher than the predetermined temperature, its stiffness becomes lower than the predetermined stiffness and the stiffness-variable region may deform so as to become stretchable.