Shock-Absorbing Layer in Foldable Display Devices

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Solution Overview

Problem

Foldable display devices face challenges in maintaining strength and durability against external impacts due to their flexible and foldable nature, which can lead to structural deformation and reduced reliability under stress.

Innovation Solution

The implementation of a display device structure that includes a shock-absorbing layer, a functional layer, coupling interlayers, and a light-barrier pattern, along with a buffering layer and support film, to enhance durability and resistance to external impacts by distributing stress and preventing structural deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of moving object

If a foldable display device structure is used to provide a larger screen, then the display area is increased, but the strength and durability against external impacts deteriorate

Engineering Contradiction:

Improvedisplay areaVSAvoidstrength against external impact

Core Design Contradiction:

Area of moving objectVSStrength

Solution Approach 1:

A shock-absorbing layer is introduced between the cover window and the functional layer to absorb external impacts before they reach the display panel. This cushioning layer prevents direct transmission of impact forces, thereby protecting the foldable display structure while maintaining its flexibility and large display area capability

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Area of moving object

If a foldable display device structure is used to provide a larger screen, then the display area is increased, but the reliability under stress deteriorates

Engineering Contradiction:

Improvedisplay areaVSAvoidreliability under stress

Core Design Contradiction:

Area of moving objectVSReliability

Solution Approach 1:

The shock-absorbing layer serves as a protective barrier that absorbs stress and impact forces before they can cause damage to the display panel. This beforehand cushioning mechanism ensures the display device maintains high reliability under various stress conditions while preserving the foldable structure's integrity

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The display device employs a composite structure combining the cover window, shock-absorbing layer, functional layer, and coupling interlayers. This multi-layer composite design distributes stress across different materials with complementary properties, enhancing overall reliability while maintaining the foldable form factor

Inventive Principle:

Principle #40Composite materials

3Stability of the object's composition

If coupling interlayers with thickness of 20-50 μm are used to connect layers, then the structural integrity is improved, but the device complexity increases

Engineering Contradiction:

Improvestructural integrityVSAvoiddevice complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The coupling interlayers are designed with an optimized thickness parameter ranging from 20-50 μm. This specific thickness range provides sufficient mechanical strength to bond the cover window, shock-absorbing layer, and functional layer while remaining thin enough to avoid excessive device thickness and complexity. The parameter optimization balances structural integrity with device simplicity

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 proposed structure significantly improves the display device's ability to withstand external impacts, reducing stress and deformation, and enhancing its reliability and durability, as demonstrated by improved performance metrics such as reduced repulsive force and minimized wrinkle formation.

Implementation Method 1

a shock-absorbing layer between the cover window and the functional layer

Methodology Applied

Scientific EffectShock absorption: Damping

Implementation Method 2

distributing stress and preventing structural deformation

Methodology Applied

Scientific EffectStress distribution:

Implementation Method 3

a first coupling interlayer which is between the shock-absorbing layer and the functional layer and couples the shock-absorbing layer and the functional layer to each other

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 4

a light-barrier pattern in the non-display area

Methodology Applied

Scientific EffectLight blocking: Absorption (EM radiation)

Data Source

PatentUS11177458B2Display device having shock absorbing layer

Publication Date: 2021.11.16 SAMSUNG DISPLAY CO LTD

AI summary

A display device includes a display panel; a cover window facing the display panel; a functional layer between the display panel and the cover window; a shock-absorbing layer between the cover window and the functional layer; a first coupling interlayer which is between the shock-absorbing layer and the functional layer and couples the shock-absorbing layer and the functional layer to each other; and a second coupling interlayer which is between the shock-absorbing layer and the cover window and couples the shock-absorbing layer and the cover window to each other. A thickness of the first coupling interlayer and the second coupling interlayer ranges from about 20 micrometers to about 50 micrometers.