Flexible Display Wiring with Opening Pattern to Reduce Stress Concentration

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Solution Overview

Problem

Flexible display devices, such as foldable organic electroluminescence (organic EL) displays, face issues with stress concentration and disconnection of lines when folded, leading to reduced reliability due to cracking of gate insulating layers and interlayer insulating layers.

Innovation Solution

The implementation of a flexible substrate with a wiring structure featuring a first conductive layer having an opening pattern in partial areas, which improves durability against folding by dividing the wiring into separate portions and reducing stress concentration, thereby preventing complete disconnection even if one portion is disconnected.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If continuous wiring is used in flexible display devices, then electrical connectivity is maintained, but stress concentration occurs during folding leading to line disconnection and reduced reliability

Engineering Contradiction:

Improvewiring durabilityVSAvoidstress resistance

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The continuous wiring is divided into multiple separate wiring portions with gaps between them. This segmentation prevents stress concentration at any single point during folding, as the gaps allow the flexible substrate to bend without creating high-stress concentration points that would cause disconnection in continuous wiring structures.

Inventive Principle:

Principle #1Segmentation

2Reliability

If wiring is divided into separate portions to reduce stress concentration, then folding durability is improved, but electrical connectivity may be interrupted

Engineering Contradiction:

Improvefolding durabilityVSAvoidelectrical connectivity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The wiring structure has different properties in different regions: the wiring portions are positioned and sized to provide electrical connectivity where needed, while the gaps are strategically located to relieve stress during folding. This local differentiation allows the structure to simultaneously achieve both electrical functionality and folding durability.

Inventive Principle:

Principle #3Local quality

3Reliability

If gaps are introduced in the wiring structure to prevent stress concentration, then folding reliability is improved, but wiring resistance increases

Engineering Contradiction:

Improvefolding reliabilityVSAvoidwiring resistance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The gaps in the wiring are designed to be partial rather than complete breaks - they are sized and positioned to provide sufficient stress relief during folding while maintaining adequate electrical conductivity. The wiring portions are dimensioned to provide enough conductive path to keep resistance increases within acceptable limits while still achieving the stress concentration reduction benefit.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS10566408B2Display device

Publication Date: 2020.02.18 MAGNOLIA WHITE CORP

AI summary

Provided is a highly reliable display device that does not easily cause a wiring or an interlayer insulating layer to be cracked when being folded. A display device includes a flexible substrate; a plurality of pixels arrayed on the substrate; and a wiring, provided on the substrate, transmitting a signal to drive the plurality of pixels. The wiring includes a first conductive layer having an opening pattern at least in a partial area thereof.