Misaligned Dual-Layer Mesh Optical Film for Flexible Displays
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Solution Overview
Problem
Flexible optical films used in display devices, such as polarization and phase retardation films, face issues with cracking when subjected to extreme bending due to excessive stress, which exceeds their rupture strength.
Innovation Solution
The implementation of a dual-layer optical film structure comprising a first mesh pattern layer and a second mesh pattern layer, or a mesh pattern layer and a dot pattern layer, where the centers of the mesh patterns are misaligned, dispersing stress and reducing the maximum stress applied during bending, thereby minimizing crack occurrence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single-layer optical film is used to achieve flexibility, then the film can be bent, but the maximum stress during bending exceeds the rupture strength causing cracks
Solution Approach 1:
The optical film is divided into multiple layers (first mesh pattern layer and second mesh pattern layer) with different structural characteristics. Each layer segments the stress distribution during bending, preventing stress concentration that would cause cracks in a single-layer structure.
Solution Approach 2:
The patent creates a composite optical film structure combining mesh pattern layers with different geometries and material properties. This composite structure integrates the flexibility needed for bending with enhanced strength to prevent rupture, resolving the contradiction between adaptability and strength.
2Shape
If the optical film is stretched to achieve flexibility, then the film can conform to curved surfaces, but cracks occur entirely over the bent portion due to excessive stress
Solution Approach 1:
The mesh patterns in different layers are designed with different geometries and orientations, segmenting the stress paths during stretching and bending. This prevents stress concentration along single continuous lines, thereby preventing crack formation and maintaining reliability on curved surfaces.
Solution Approach 2:
Each mesh pattern layer is designed with specific local geometric characteristics optimized for its position in the stack. The first and second mesh patterns have different local structures that work together to distribute stress locally during bending, preventing crack initiation and propagation.
Data Source
AI summary
An optical film for a display device includes: a first mesh pattern layer in which a plurality of first mesh patterns each including a first inner hole are arranged; and a second mesh pattern layer which faces the first mesh pattern layer, and in which a plurality of second mesh patterns each including a second inner hole are arranged, wherein a center of the first mesh pattern and a center of the second mesh pattern are arranged to be misaligned.