Foldable Display Asymmetric Optical Hole Stress Management
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Solution Overview
Problem
Foldable display devices face defects such as inter-component interference, cracks in the thin film encapsulation layer, and peeling of polarizing members due to stress applied during folding, which can weaken the cover window and lead to optical shadow issues.
Innovation Solution
A foldable display device design featuring a through hole and an optical hole with asymmetrical dimensions, where the width in the direction perpendicular to the folding line is greater than the width in the same direction as the folding line, to minimize stress and prevent defects like interference and optical shadows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If optical holes are physically perforated to increase transmittance, then light transmittance is improved, but the cover window becomes weaker and more susceptible to stress-induced defects
Solution Approach 1:
The patent applies asymmetry by designing the optical hole with different dimensions in the first direction (parallel to folding line) versus the second direction (perpendicular to folding line). Specifically, the optical hole has a larger width in the second direction than in the first direction. This asymmetric design allows sufficient light transmittance while maintaining structural strength by reducing the hole area in the critical first direction where stress concentration occurs during folding.
2Ease of operation
If the display device is folded, then portability is improved, but stress is applied to layers causing inter-component interference, cracks, and peeling
Solution Approach 1:
The asymmetric optical hole design with larger width in the second direction (perpendicular to folding line) than in the first direction (parallel to folding line) reduces stress concentration during folding operations. This allows the display device to maintain layer integrity and prevent defects while preserving foldability and portability.
3Ease of manufacture
If the optical hole has equal width in both directions, then manufacturing is simplified, but stress during folding causes defects and optical shadows
Solution Approach 1:
The patent implements asymmetry in the optical hole dimensions, with the width in the second direction (perpendicular to folding line) being larger than the width in the first direction (parallel to folding line). This asymmetric configuration prevents stress-induced defects and optical shadows during folding while remaining manufacturable through standard fabrication processes.
Data Source
AI summary
A foldable display device includes a display panel, a folding line extending in a first direction, a first non-folding area disposed on a first side of the folding line and which extends in a second direction perpendicular to the first direction, a second non-folding area disposed on a second side of the folding line opposite the first side and which extends in the second direction, and a through hole defined in the first non-folding area and which penetrates the display panel in a thickness direction. In a plan view, a first maximum width of the through hole in the first direction is smaller than a second maximum width of the through hole in the second direction.