Foldable Display Protective Films for Stress Management
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Solution Overview
Problem
Foldable display apparatuses face challenges in maintaining structural integrity during folding and unfolding due to uneven stress distribution, leading to potential buckling or repulsive forces that hinder smooth operation.
Innovation Solution
A foldable display apparatus with a flexible display panel supported by a case, featuring a first protective film with a high elastic modulus for compressive stress areas and a second protective film with a polymer material for tensile stress areas, ensuring appropriate stress management and preventing buckling or repulsive forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single protective film is used for the flexible display panel, then the structure is simple and easy to manufacture, but the panel experiences buckling and repulsive forces during folding due to uneven stress distribution
Solution Approach 1:
The protective film is divided into two separate films: a first protective film applied to the out-folding portion and a second protective film applied to the in-folding portion. This segmentation allows each film to be optimized for its specific stress conditions, preventing buckling and repulsive forces during folding operations.
Solution Approach 2:
Different regions of the flexible display panel are assigned different protective films with properties suited to their local stress requirements. The out-folding portion receives a first protective film designed to handle compressive stress, while the in-folding portion receives a second protective film designed for tensile stress, ensuring optimal performance in each local area.
2Stability of the object's composition
If the protective film has high rigidity to prevent buckling, then structural stability is improved, but repulsive forces increase during in-folding operations
Solution Approach 1:
The first protective film for the out-folding portion is designed with higher rigidity to prevent buckling under compressive stress, while the second protective film for the in-folding portion is designed with lower rigidity to reduce repulsive forces during folding. This local differentiation of mechanical properties resolves the contradiction between stability and force resistance.
Solution Approach 2:
The rigidity parameter of the protective film is changed based on the folding region. The first protective film has a higher elastic modulus optimized for compressive stress resistance, while the second protective film has a lower elastic modulus optimized for tensile stress accommodation, thereby preventing both buckling and excessive repulsive forces.
3Strength
If the protective film is made of rigid material to resist compressive stress, then out-folding stability is improved, but the film cannot accommodate tensile stress during in-folding
Solution Approach 1:
The protective film system is segmented into two distinct films with different material properties. The first protective film uses rigid material optimized for compressive stress resistance in the out-folding portion, while the second protective film uses flexible material optimized for tensile stress accommodation in the in-folding portion, achieving both compressive strength and stress type adaptability.
Solution Approach 2:
The protective film system employs composite material construction with two different materials: a rigid material for the first protective film that resists compressive stress, and a flexible material for the second protective film that accommodates tensile stress. This composite approach allows the overall system to handle both types of stress effectively.
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 effectively reduces buckling and repulsive forces, allowing for stable folding and unfolding of the display panel, enhancing the durability and usability of the foldable display apparatus.
Implementation Method 1
the first protective film includes a metal film. An elastic coefficient of the metal film may be about 10 Gpa or greater
Implementation Method 2
the second protective film may include a polymer film
Data Source
AI summary
A foldable display apparatus includes a flexible display panel that is foldable, and a case configured to support the flexible display panel, wherein the flexible display panel includes a first protective film at a first region corresponding to an out-folding portion, and a second protective film at a second region corresponding to an in-folding portion, wherein the in-folding portion and the out-folding portion have opposite directions of curvature, and wherein the first and second protective films include different materials.