Foldable Display Protective Layer Stack for Crack-Resistant Optics

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Solution Overview

Problem

Flexible electronic apparatuses face challenges in maintaining reliable operation and display quality due to the need for improved folding reliability of their components.

Innovation Solution

A display device with a protective member comprising a base layer, a hard coating layer, a first low refractive index layer, and a primer layer containing a metal compound and a polar compound, which includes titanium alkoxide oligomers or zirconium chelate compounds, enhances folding reliability and display quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a protective member with multiple layers is applied to improve display quality and folding reliability, then the display quality and folding reliability are improved, but the device complexity increases

Engineering Contradiction:

Improvefolding reliabilityVSAvoidprotective member structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The protective member is divided into multiple functional layers: a base layer providing mechanical support, a hard coating layer providing scratch resistance, a first low refractive index layer reducing light reflection, and a primer layer enhancing adhesion. This segmentation allows each layer to optimize its specific function while collectively improving folding reliability and display quality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The protective member uses composite material structure combining organic and inorganic materials. The base layer uses flexible polymer material, the hard coating layer uses inorganic material for hardness, the low refractive index layer uses porous inorganic material for optical properties, and the primer layer combines metal compounds and polar compounds for adhesion. This composite approach resolves the contradiction by achieving superior reliability through material diversity while managing complexity through functional specialization.

Inventive Principle:

Principle #40Composite materials

2Strength

If a hard coating layer is applied to improve durability, then the durability is improved, but the flexibility required for folding is reduced

Engineering Contradiction:

ImprovedurabilityVSAvoidflexibility

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

Different layers of the protective member have different mechanical properties tailored to their specific functions. The base layer maintains flexibility to enable folding, while the hard coating layer provides localized hardness for durability. This local differentiation resolves the contradiction by allowing the protective member as a whole to be both flexible and durable.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The protective member is designed as a thin-film structure where the hard coating layer is applied as a thin film on the flexible base layer. This thin-film approach allows the hard coating to provide durability without significantly increasing overall thickness or compromising the flexibility needed for folding operations.

Inventive Principle:

Principle #30Flexible shells and thin films

3Illumination intensity

If multiple layers with different refractive indices are applied to improve display quality, then the display quality is improved, but the manufacturing precision requirements increase

Engineering Contradiction:

Improvedisplay qualityVSAvoidlayer thickness control

Core Design Contradiction:

Illumination intensityVSManufacturing precision

Solution Approach 1:

The protective member utilizes refractive index as a key parameter to optimize display quality. The first low refractive index layer has a refractive index lower than the hard coating layer, creating optical interference that reduces light reflection and improves display visibility. By controlling the refractive index parameter and layer thickness, the invention achieves enhanced display quality while managing manufacturing precision through optical design rather than requiring extremely tight dimensional tolerances.

Inventive Principle:

Principle #35Parameter changes

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 protective member improves the folding reliability and display quality of flexible electronic apparatuses by providing a durable and efficient protective layer that withstands repeated folding and maintains image clarity.

Implementation Method 1

a primer layer configured to reduce stress between the hard coating layer and the first low refractive index layer

Methodology Applied

Scientific EffectStress reduction:

Implementation Method 2

the protective member may prevent crack occurrence at a folding area of the display panel

Methodology Applied

Scientific EffectCrack prevention:

Data Source

PatentUS20260072475A1Display device and electronic apparatus including the display device

Publication Date: 2026.03.12 SAMSUNG DISPLAY CO LTD

AI summary

A display device may include a display panel foldable based on at least one folding axis, and a protective member disposed on the display panel. The protective member may include a base layer, a hard coating layer disposed on the base layer, a first low refractive index layer disposed on the hard coating layer, and a primer layer disposed between the hard coating layer and the first low refractive index layer. The primer layer may include a metal compound and a polar compound, the metal compound may include a titanium alkoxide oligomer, a zirconium alkoxide oligomer, or a zirconium chelate compound, and a number of carbon atoms included in the titanium alkoxide oligomer may be 96 to 320. Accordingly, the display device may show excellent display quality and excellent folding reliability.