Nanofiber Touch Sensor for Foldable Displays
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Solution Overview
Problem
Foldable display devices face challenges in maintaining touch sensitivity and reliability due to the stress applied during folding, which can damage the touch member's conductive patterns.
Innovation Solution
Incorporating a touch member with conductive patterns that include a fiber layer of nanofibers with cavities, a first and second conductive layer, and a partition made of silicon oxide, silicon nitride, or silicon oxynitride, which are designed to relieve folding stress and enhance flexibility, while maintaining touch sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional rigid conductive pattern is used in the touch member, then the touch sensitivity is maintained, but the reliability deteriorates due to folding stress damage
Solution Approach 1:
The patent applies this principle by replacing the rigid conductive pattern with a flexible nanofiber layer. The nanofibers are formed through electrospinning, creating a thin film structure that can bend and deform without breaking during folding operations, thus maintaining reliability while reducing folding stress damage.
Solution Approach 2:
The patent applies this principle by creating a porous structure within the nanofibers through cavities. These cavities are formed by etching nanoparticles from the nanofiber matrix, resulting in a lightweight, flexible, and stress-resistant conductive layer that maintains electrical conductivity while accommodating folding deformations.
2Reliability
If the conductive pattern is made flexible to withstand folding, then the reliability improves, but the touch sensitivity deteriorates
Solution Approach 1:
The patent applies this principle by creating a composite conductive structure consisting of nanofibers, cavities, and polymer filler. This composite material combines the flexibility of nanofibers with the conductivity of the filler, achieving both reliability during folding and maintained touch sensitivity through preserved electrical properties.
Solution Approach 2:
The patent applies this principle by controlling the physical and chemical parameters of the conductive layer during electrospinning and etching processes. By adjusting fiber diameter, cavity size, and filler concentration, the material achieves optimal balance between flexibility for reliability and electrical conductivity for touch sensitivity.
3Reliability
If a fiber layer with cavities is introduced to relieve folding stress, then the reliability improves, but the device complexity increases
Solution Approach 1:
The patent applies this principle by replacing traditional multi-layer rigid conductive structures with a single nanofiber-based conductive layer created through electrospinning. This substitution simplifies the device architecture while the inherent nanofiber flexibility and cavity structure provide the necessary stress relief for improved reliability.
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 effectively strengthens the display device against folding stress, enhancing its reliability and maintaining touch sensitivity by using a fiber layer with cavities and a partition to distribute and reduce the stress on the conductive patterns.
Implementation Method 1
the nanofibers includes a plurality of cavities
Implementation Method 2
a fiber layer including a plurality of nanofibers... designed to relieve folding stress and enhance flexibility
Data Source
AI summary
A display device including a display panel configured to display an image and having a folding area by which the display panel is configured to be folded along a folding axis, and a touch member disposed on the display panel and configured to detect an external touch signal. The touch member includes a plurality of first conductive patterns disposed to overlap the folding area, in which each of the first conductive patterns includes a fiber layer including a plurality of nanofibers, and the nanofibers includes a plurality of cavities.