Foldable Display Protective Member Thickness Variation

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Solution Overview

Problem

Foldable display devices face stress issues in the folding area, leading to potential damage or breakage of the protective member, as the stress in this area is greater than in non-folding areas.

Innovation Solution

A display device design featuring a protective member with varying thicknesses in different areas, including a thinner section in the folding area, and the use of adhesives and cushions to distribute stress, along with a concave shape for the protective member surfaces to reduce stress concentration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the protective member has uniform thickness across all areas, then it provides consistent protection, but stress concentration occurs in the folding area leading to damage or breakage

Engineering Contradiction:

Improvefolding reliabilityVSAvoidprotective member strength in folding area

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The protective member is designed with different thicknesses in different areas: a first thickness in the folding area and a second thickness in the non-folding area. This local differentiation allows the folding area to have reduced stress concentration while maintaining adequate protection, resolving the contradiction between uniform protection and folding reliability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The thickness parameter of the protective member is changed based on location. By making the protective member thinner in the folding area and thicker in the non-folding area, the design adapts the structural parameter to the local stress conditions, preventing breakage while maintaining overall protection.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the protective member is made thinner in the folding area to reduce stress, then folding reliability improves, but protection capability in that area decreases

Engineering Contradiction:

Improvefolding reliabilityVSAvoidprotection capability against external factors

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The protective member provides different levels of protection locally: thinner in the folding area to enable reliable folding, and thicker in the non-folding area to provide enhanced protection against external factors. This spatial differentiation of protective quality resolves the contradiction between folding reliability and protection capability.

Inventive Principle:

Principle #3Local quality

3Reliability

If the protective member surfaces are made concave to distribute stress, then stress concentration is reduced, but manufacturing complexity increases

Engineering Contradiction:

Improvestress distributionVSAvoidprotective member manufacturing

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The protective member features concave top and bottom surfaces instead of flat surfaces. This curvature design helps distribute stress more evenly across the structure, particularly in the folding area, reducing stress concentration while maintaining manufacturability through standard forming processes.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentUS10957867B2Display device

Publication Date: 2021.03.23 SAMSUNG DISPLAY CO LTD

AI summary

A display device includes a display module, a protective member under the display module, and an adhesive member between the display module and the protective member. The display module includes a folding area foldable along a folding axis, a first non-folding area, and a second non-folding area, and the folding area is between the first and second non-folding areas. A first thickness of the protective member overlapping with the folding area is less than a second thickness of the protective member overlapping with the first non-folding area and a third thickness of the protective member overlapping with the second non-folding area.