Flexible Display Wiring Stress Management via Neutral Plane Alignment

Solution Overview

Problem

Flexible display devices face damage to wirings due to bending stress, as the central and peripheral areas of the wiring area have different deformation characteristics, leading to uneven stress distribution and potential damage to the wiring layer.

Innovation Solution

The thickness and Young's modulus of the flexible substrate and protection layer are varied between the central and peripheral areas to align the wiring layer with the neutral plane, reducing stress on the wiring layer and preventing damage by adjusting the radius of curvature and deformation characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the wiring area is bent to reduce frame size, then the display device achieves flexibility and compact form factor, but the wirings are damaged by bending stress

Engineering Contradiction:

ImproveflexibilityVSAvoidwiring integrity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies local quality by making the protection layer thickness non-uniform: the third region (peripheral area) has a greater thickness than the second region (central area). This localized thickness variation provides enhanced stress protection where needed most during bending, while maintaining flexibility in the central display area.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the physical parameter of the protection layer thickness to resolve the contradiction. By increasing the thickness in the peripheral region compared to the central region, the structure can withstand bending stresses while maintaining flexibility. This parameter modification allows the wiring area to be bent without damaging the wirings.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the protection layer thickness is increased to protect wirings, then wiring damage is prevented, but the display device loses flexibility

Engineering Contradiction:

Improvewiring protectionVSAvoidflexibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by making the protection layer thickness non-uniform: the third region (peripheral area) has a greater thickness than the second region (central area). This localized thickness variation provides enhanced stress protection where needed most during bending, while maintaining flexibility in the central display area.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the physical parameter of the protection layer thickness to resolve the contradiction. By increasing the thickness in the peripheral region compared to the central region, the structure can withstand bending stresses while maintaining flexibility. This parameter modification allows the wiring area to be bent without damaging the wirings.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the first substrate thickness is varied between central and peripheral areas, then stress distribution is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvestress distributionVSAvoidsubstrate fabrication

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies local quality by making the protection layer thickness non-uniform: the third region (peripheral area) has a greater thickness than the second region (central area). This localized thickness variation provides enhanced stress protection where needed most during bending, while maintaining flexibility in the central display area.

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

This solution effectively prevents damage to the wirings by ensuring the wiring layer is not subjected to tensile stress, enhancing the reliability of the display device by distributing stress evenly across the bending area.

Implementation Method 1

align the wiring layer with the neutral plane, reducing stress on the wiring layer

Methodology Applied

Scientific EffectNeutral plane alignment:

Implementation Method 2

distributing stress evenly across the bending area

Methodology Applied

Scientific EffectStress distribution:

Data Source

PatentUS10459264B2Display device

Publication Date: 2019.10.29 MAGNOLIA WHITE CORP

AI summary

According to one embodiment, a display device includes a first substrate including a first area and a second area, the first area including a display area where pixels are arranged, and the second area being adjacent to the first area and where wirings are arranged, wherein the wirings are covered with a protection layer, the second area includes a peripheral area and a central area in an arrangement direction of the wirings, and a thickness of at least one of the first substrate and the protection layer varies between the peripheral area and the central area.