Foldable Display Protective Film With Local Modulus Tuning
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Solution Overview
Problem
Foldable display devices require a protective film that balances impact resistance and flexibility, especially in the folding area, to protect internal components while allowing for easy folding and unfolding.
Innovation Solution
A display device with a protective film that includes a first region and a second region made of the same material but with different moduli, where the second region, with a lower modulus, is disposed in the folding area. This configuration is achieved by laser radiation to the polymer film during manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a protective film with high durability and hardness is used to protect internal components, then impact resistance is improved, but flexibility and ease of folding deteriorate
Solution Approach 1:
The protective film is divided into two regions with different moduli: a first region with higher modulus for impact resistance and a second region with lower modulus for flexibility in the folding area. This local differentiation allows each region to perform its specific function optimally - the first region protects against impacts while the second region enables easy folding without cracking.
Solution Approach 2:
The protective film is segmented into distinct functional zones (first region and second region) with different mechanical properties. The segmentation is achieved through laser irradiation that modifies the polymer structure in specific areas, creating a multi-functional film that simultaneously provides protection and flexibility.
2Reliability
If the protective film is made hard to protect internal components, then reliability is improved, but the device complexity increases due to multiple material layers
Solution Approach 1:
Instead of using multiple layers of different materials, the patent changes the physical-chemical parameters of a single polymer film through laser irradiation. The laser modifies the molecular structure and cross-linking density in the first region, increasing its modulus while maintaining the base material's flexibility in the second region. This parameter change approach achieves high reliability with a simpler single-layer structure.
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 protective film provides improved impact resistance and flexibility, enhancing the durability and ease of folding of the display device, while also improving manufacturing efficiency by modifying the film's properties through laser treatment.
Implementation Method 1
radiating a laser to the folding area of the polymer film to form a first region and a second region having different moduli from each other
Implementation Method 2
radiating a laser to the folding area of the polymer film to form a first region and a second region having different moduli from each other
Data Source
AI summary
A display device including a folding area includes a display panel, a cover window disposed above the display panel, and a protective film disposed on the cover window, where the protective film includes a first region and a second region including a same material as each other and having different moduli from each other. A modulus of the second region of the protective film is less than a modulus of the first region, and the second region is disposed in the folding area.