Foldable Display Light Guide Member Stress Relief
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Solution Overview
Problem
Foldable display devices face challenges with internal light extraction efficiency, external light reflectance, and stress relief during folding, which can lead to damage and image quality issues.
Innovation Solution
A foldable display apparatus featuring a light guide member with a plurality of lens patterns in the non-folding area and an intermediate layer in the folding area, where the modulus difference between the upper and lower surfaces of the intermediate layer is minimized to alleviate stress and prevent peeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If lens patterns are added to improve light extraction efficiency, then internal light extraction efficiency is improved, but external light reflectance increases causing Rainbow Mura and Ring Mura phenomena
Solution Approach 1:
The patent applies different structures to different regions: lens patterns are provided only in the non-folding area to improve light extraction, while the folding area uses a flat structure to minimize external light reflection and avoid Rainbow Mura and Ring Mura phenomena. This local differentiation resolves the contradiction between light extraction efficiency and external light reflectance.
2Manufacturing precision
If the light guide member structure is optimized for light extraction, then image quality is improved, but stress during folding increases causing peeling and damage
Solution Approach 1:
The light guide member is segmented into two distinct areas: a non-folding area with lens patterns for optimal light extraction and image quality, and a folding area with a flat structure that minimizes stress concentration. This segmentation allows each area to be optimized for its specific function, resolving the contradiction between image quality and stress resistance.
Solution Approach 2:
Different structural qualities are applied locally: the non-folding area has lens patterns for light extraction optimization, while the folding area has a flat, stress-distributing structure. This local quality differentiation enables the member to simultaneously achieve good image quality and resistance to folding-induced peeling and damage.
3Adaptability or versatility
If the light guide member is made flexible for folding, then portability is improved, but internal light extraction efficiency decreases
Solution Approach 1:
The light guide member is divided into a folding area with a flat structure that accommodates bending and folding movements, and a non-folding area with lens patterns that maintain fixed light extraction efficiency. This segmentation allows the member to be flexible where needed while maintaining optical performance where structure is required.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances light extraction efficiency, reduces Rainbow Mura and Ring Mura phenomena, and minimizes stress-related damage during folding, resulting in improved image quality and extended device lifespan.
Implementation Method 1
a light guide member disposed on the display panel and including the folding area and the non-folding area, wherein the light guide member includes a plurality of first lens patterns disposed in the non-folding area
Implementation Method 2
an intermediate layer disposed in the folding area, wherein a difference between a modulus of an upper surface of the intermediate layer and a modulus of a lower surface of the intermediate layer is smaller than a difference between a modulus of the plurality of first lens patterns and a modulus of the first filling layer
Data Source
AI summary
A foldable display apparatus in one example includes a display panel having folding area and non-folding area, and a light guide member disposed on the display panel and including the folding area and the non-folding area. The light guide member includes a plurality of first lens patterns disposed in the non-folding area, a first filling layer disposed in the non-folding area and disposed on the plurality of first lens patterns, and an intermediate layer disposed in the folding area. A difference between a modulus of an upper surface of the intermediate layer and a modulus of a lower surface of the intermediate layer is smaller than a difference between a modulus of the plurality of first lens patterns and a modulus of the first filling layer.