Lattice Support Layer for Foldable Display Stress Management

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Solution Overview

Problem

Display devices with foldable panels are prone to damage from repeated folding and unfolding due to stress on the support layer, which is easily compromised by these operations.

Innovation Solution

A display device with a support layer featuring a lattice pattern of holes, arranged in a specific pattern to distribute stress and enhance durability, allowing for repeated folding and unfolding without damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a solid support layer is used to provide structural strength, then the display device maintains rigidity and protection, but the support layer accumulates stress during repeated folding and unfolding operations leading to damage

Engineering Contradiction:
Improvestructural strength of support layerVSAvoiddurability under repeated folding operations
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The support layer is segmented into a lattice pattern consisting of multiple struts arranged in geometric shapes (triangles, squares, hexagons). This segmentation divides the continuous solid structure into discrete elements that can independently manage stress during folding and unfolding, preventing stress accumulation and structural damage while maintaining overall strength.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The support layer is designed with a porous lattice structure containing multiple voids or holes distributed throughout. This porous configuration reduces material density and allows the structure to flex during folding operations, accommodating dimensional changes without generating excessive stress, thereby improving reliability under repeated folding while maintaining sufficient structural strength.

Inventive Principle:
Principle #31Porous materials

2Adaptability or versatility

If the support layer is made flexible to accommodate folding, then the display device can be folded repeatedly, but the support layer loses structural strength and becomes easily damaged

Engineering Contradiction:
Improvefoldability of display deviceVSAvoidstructural strength of support layer
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The lattice pattern segments the support layer into multiple struts that can flex independently during folding. This segmentation allows the structure to adapt to folding movements while distributing mechanical stress across multiple elements, preventing any single point from bearing excessive load and maintaining overall structural strength during repeated folding operations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The support layer combines rigid strut elements with flexible void spaces in a composite lattice structure. This composite design enables the support layer to exhibit both flexibility (for folding adaptability) and strength (through the rigid strut framework), resolving the contradiction between foldability and structural integrity.

Inventive Principle:
Principle #40Composite materials

3Reliability

If a lattice pattern with holes is introduced to reduce stress, then the support layer becomes more durable under folding operations, but the manufacturing complexity increases

Engineering Contradiction:
Improvedurability of support layerVSAvoidstructural complexity of support layer
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The lattice pattern serves multiple functions simultaneously: it provides structural strength through the strut framework, enables flexibility for folding through the geometric arrangement, and reduces stress concentration through the distributed voids. This multi-functionality achieves improved durability without requiring additional components or complex mechanisms, as the lattice structure itself performs all necessary functions.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The lattice pattern parameters (strut thickness, hole size, geometric shape, spacing) can be adjusted to optimize the balance between durability and manufacturing complexity. By tuning these parameters, the support layer achieves enhanced durability under folding operations while maintaining manufacturability through standard fabrication processes for patterned structures.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4220349B1Display device
Publication Date: 2024.08.21 SAMSUNG DISPLAY CO LTD
  • EP4220349B1 patent drawingFigure 1
  • EP4220349B1 patent drawingFigure 2
  • EP4220349B1 patent drawingFigure 3

AI summary

A display device includes: a display module having a first non-foldable area, a foldable area, and a second non-foldable area, which are arranged in a first direction in a unfolded state; and a first support layer disposed under the display module and having a lattice pattern including a plurality of first holes overlapping the foldable area, wherein the first holes are arranged in the first direction and a second direction intersecting the first direction, and wherein: each of the first holes has a first width in the second direction and a second width in the first direction, the first width is in a first range and the second width is in a second range.