Flexible Display Cover Layer Structure for Edge Buckling Resistance

Solution Overview

Problem

Flexible displays in electronic devices, such as foldable, slidable, or rollable devices, often experience buckling and delamination issues due to concentrated compressive loads at the edge portions during deformation operations.

Innovation Solution

A reinforcing portion is formed on the glass cover applied to the display, specifically designed with a gradually decreasing thickness and protruding edges to enhance the structural integrity of the edge portions, thereby preventing buckling and delamination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a flexible display is used in slidable, foldable, or rollable electronic devices, then the display region can be extended or reduced through deformation operations, but compressive loads are concentrated on the edge portions causing buckling and delamination

Engineering Contradiction:

Improvedisplay deformation capabilityVSAvoidedge portion strength

Core Design Contradiction:

Adaptability or versatilityVSStrength

Solution Approach 1:

The cover layer is designed with varying thickness to provide different mechanical properties at different locations. The first portion has a greater thickness to provide enhanced strength and buckling resistance at the edge portions where compressive loads are concentrated, while the second portion has a smaller thickness to maintain flexibility and enable deformation operations. This local quality variation resolves the contradiction by strengthening the edge portions without compromising the overall flexibility of the display.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The cover layer transitions from a two-dimensional uniform structure to a three-dimensional variable thickness structure. By introducing thickness variation as an additional dimensional parameter, the design can simultaneously achieve edge reinforcement for buckling prevention and overall flexibility for deformation operations, thus resolving the contradiction between edge strength and display adaptability.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If the cover layer has uniform thickness, then manufacturing is simplified, but the edge portions are susceptible to buckling and delamination under compressive loads

Engineering Contradiction:

Improvecover layer manufacturing simplicityVSAvoiddisplay integrity

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The cover layer is designed with varying thickness to provide different mechanical properties at different locations. The first portion has a greater thickness to provide enhanced strength and buckling resistance at the edge portions where compressive loads are concentrated, while the second portion has a smaller thickness to maintain flexibility and enable deformation operations. This local quality variation resolves the contradiction by strengthening the edge portions without compromising the overall flexibility of the display.

Inventive Principle:

Principle #3Local quality

3Strength

If the thickness of the cover layer is increased to prevent buckling, then edge strength is improved, but the flexibility and deformability of the display is reduced

Engineering Contradiction:

Improveedge portion strengthVSAvoiddisplay flexibility

Core Design Contradiction:

StrengthVSEase of operation

Solution Approach 1:

The cover layer is designed with varying thickness to provide different mechanical properties at different locations. The first portion has a greater thickness to provide enhanced strength and buckling resistance at the edge portions where compressive loads are concentrated, while the second portion has a smaller thickness to maintain flexibility and enable deformation operations. This local quality variation resolves the contradiction by strengthening the edge portions without compromising the overall flexibility of the display.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The cover layer is divided into two distinct portions: a first portion with greater thickness for edge reinforcement and a second portion with smaller thickness for flexibility. This segmentation allows each portion to perform its specific function optimally, with the thicker first portion preventing buckling at stress-concentrated edges while the thinner second portion maintains the display's ability to deform during sliding, folding, or rolling operations.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS12349296B2Flexible display and electronic device including the same

Publication Date: 2025.07.01 SAMSUNG ELECTRONICS CO LTD

AI summary

An example flexible display includes a panel layer and a cover layer disposed on one surface of the panel layer. The cover layer includes a first portion and a second portion that extends from the first portion in a first direction. The first portion includes a first base portion having a first thickness and a first connecting portion that extends from the first base portion and has a gradually decreasing thickness. The second portion includes a second base portion that is connected with the first connecting portion and that has a second thickness smaller than the first thickness and a reinforcing portion that protrudes from an edge of the second base portion that faces in a second direction perpendicular to the first direction. The reinforcing portion includes an edge portion that protrudes from a partial region of the second base portion to have a third thickness and a second connecting portion that extends from the edge portion toward the second base portion and has a gradually decreasing thickness.