Segmented Hard Coating and Self-Healing Layer for Flexible Displays

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Solution Overview

Problem

Flexible display devices face a challenge in balancing flexibility and hardness, as a window layer made of rigid materials to prevent damage reduces flexibility, while flexible materials are prone to surface damage from contact.

Innovation Solution

A flexible display device is designed with a window substrate featuring independently segmented high hardness coating layers and a self-healing coating layer made of elastomers like silicones or urethanes, which covers the hard coating layer to provide protection and maintain flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the window layer is made of a rigid material to reduce or prevent damage to the surface of the window layer, then the hardness of the window layer is improved, but the flexibility of the display device decreases

Engineering Contradiction:

Improvehardness of window layerVSAvoidflexibility of display device

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

The hard coating layer is divided into multiple independently segmented coating layers that are spaced apart from each other. This segmentation allows the hard coating to provide surface protection while the gaps between coating layers maintain the overall flexibility of the window substrate, resolving the contradiction between hardness and flexibility.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The window substrate has different properties in different regions: the coating layers provide localized hardness and damage resistance, while the base layer and gap regions maintain flexibility. This local differentiation allows simultaneous achievement of both hardness and flexibility without requiring the entire structure to be rigid or flexible.

Inventive Principle:

Principle #3Local quality

2Adaptability or versatility

If the window layer is made of a flexible material to maintain flexibility, then the flexibility of the display device is improved, but the surface of the window layer becomes more easily damaged by contact

Engineering Contradiction:

Improveflexibility of display deviceVSAvoidsurface damage from contact

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The hard coating layers are applied in advance to the flexible window substrate to create a protective surface layer before the substrate is put into service. This preliminary protective action prevents surface damage from contact while maintaining the underlying flexibility of the substrate.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The window substrate combines a flexible base layer with hard coating layers to create a composite structure. The flexible base layer provides overall flexibility and bendability, while the hard coating layers provide surface durability and resistance to contact damage, simultaneously achieving both flexibility and damage resistance.

Inventive Principle:

Principle #40Composite materials

3Strength

If coating layers are added to increase hardness, then the hardness of the window substrate is improved, but the complexity of the window substrate structure increases

Engineering Contradiction:

Improvehardness of window substrateVSAvoidstructure of window substrate

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The coating layer structure is segmented into multiple independent layers spaced apart from each other. This segmentation simplifies the manufacturing process compared to applying a single continuous hard coating, as each coating layer can be applied and cured independently, reducing overall structural complexity while maintaining hardness.

Inventive Principle:

Principle #1Segmentation

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 allows for simultaneous implementation of flexibility and high hardness, minimizing damage to the coating layer by imparting healing properties to the hard coating layer, thus protecting it from external impacts.

Implementation Method 1

a self-healing coating layer including a self-healing material and covering the hard coating layer on the base layer

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS10331172B2Flexible window substrate and flexible display device having the same

Publication Date: 2019.06.25 SAMSUNG DISPLAY CO LTD

AI summary

There is provided a flexible display device including a display panel for displaying an image, and a window substrate covering the touch screen panel, the widow substrate including a flexible base layer including an externally facing first surface, and a second surface opposite the first surface and facing the display panel, a hard coating layer having a hardness that is larger than that of the base layer, and including a plurality of coating tiles on the first surface of the base layer that are spaced to have a gap between adjacent ones of the coating tiles, and a self-healing coating layer including a self-healing material and covering the hard coating layer on the base layer.