Bendable Display Stress Distribution via Segmented Encapsulation

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Solution Overview

Problem

Display devices with bendable or foldable structures face reliability issues due to stress concentration at bent areas, which can lead to damage and reduced performance.

Innovation Solution

A display device design that includes a substrate with a display area and a peripheral area, featuring light-emitting diodes, inorganic and organic encapsulation layers, and inorganic patterns to distribute stress and enhance reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the display panel is made bendable to achieve thinness and light weight, then adaptability and form factor are improved, but stress concentration occurs at bent areas leading to reduced reliability

Engineering Contradiction:

ImprovebendabilityVSAvoiddamage resistance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The encapsulation layer is divided into multiple inorganic encapsulation layers and organic encapsulation layers stacked alternately. This segmentation allows each layer to independently manage stress, preventing stress concentration from propagating through the entire structure, thereby maintaining reliability in bendable display panels

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses a composite encapsulation structure combining inorganic encapsulation layers (such as silicon oxide, silicon nitride) with organic encapsulation layers (such as polyimide, acrylic resin). This composite material approach leverages the advantages of both material types: inorganic layers provide barrier properties and stress distribution, while organic layers provide flexibility and adhesion, enabling the display panel to be bendable without compromising reliability

Inventive Principle:

Principle #40Composite materials

2Reliability

If the encapsulation layer is made thicker to improve protection against stress, then reliability is improved, but device thickness and weight increase

Engineering Contradiction:

Improvestress resistanceVSAvoiddevice weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

Instead of using a single thick encapsulation layer, the patent segments the encapsulation into multiple thin inorganic and organic layers. This segmented structure provides equivalent or superior stress resistance compared to a single thick layer, while maintaining thinner overall device profile and reduced weight

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent employs thin-film encapsulation technology where multiple ultrathin inorganic and organic layers are deposited sequentially. These thin films collectively provide robust stress resistance and protection, eliminating the need for thick encapsulation layers that would increase device weight and thickness

Inventive Principle:

Principle #30Flexible shells and thin films

Data Source

PatentUS20250143143A1Display device

Publication Date: 2025.05.01 SAMSUNG DISPLAY CO LTD

AI summary

A display device includes a substrate including a display area and a peripheral area adjacent to the display area, a plurality of light-emitting diodes arranged in the display area, a first inorganic encapsulation layer disposed on the plurality of light-emitting diodes, an organic encapsulation layer disposed on the first inorganic encapsulation layer, a plurality of inorganic patterns disposed on the organic encapsulation layer and spaced apart from each other, and a touch electrode disposed on the organic encapsulation layer and defining a plurality of electrode holes respectively overlapping the plurality of light-emitting diodes in a plan view.