Foldable Display Cover with High-Modulus Adhesive and Barrier Film
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Solution Overview
Problem
Foldable display devices face challenges in achieving a balance between surface hardness, impact resistance, and folding characteristics, particularly due to the limitations of adhesive layers between polymer films and glass substrates, which can lead to reduced dent resistance and increased stress on the glass, causing cracking or breaking during repeated folding.
Innovation Solution
A foldable display device design that incorporates a glass substrate with a first adhesive layer and a barrier film, where the adhesive layer has a high modulus of 5×10^4 Pa to 5×10^8 Pa, and the barrier film has a thickness of 30 μm to 70 μm, ensuring excellent surface hardness and impact resistance while maintaining the folding characteristic, and optionally includes a neutral plane compensation layer to reduce tensile stress on the glass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a polymer film is used as a cover member to ensure folding characteristic, then the folding characteristic is improved, but the surface hardness is worsened
Solution Approach 1:
The patent uses a laminated structure combining glass substrate and polymer film. The glass substrate provides surface hardness and scratch resistance, while the polymer film provides flexibility and folding characteristic. This composite structure resolves the contradiction by integrating materials with complementary properties.
2Adaptability or versatility
If an adhesive layer with low modulus is used to maximize folding characteristic, then the folding characteristic is improved, but the dent characteristic is worsened
Solution Approach 1:
The patent optimizes the modulus parameter of the adhesive layer to a specific range (5×10^4 Pa to 5×10^8 Pa) that balances folding characteristic and dent resistance. This parameter optimization resolves the contradiction by finding the optimal value that satisfies both requirements.
3Strength
If a modulus of the adhesive layer is increased to improve surface hardness and dent characteristic, then the surface hardness and dent characteristic are improved, but the glass base material is easily broken
Solution Approach 1:
The patent specifies a modulus range for the adhesive layer (5×10^4 Pa to 5×10^8 Pa) that prevents excessive tensile stress on the glass during folding. This parameter control resolves the contradiction by ensuring the adhesive layer is soft enough to protect the glass from breaking while still providing sufficient dent resistance.
4Adaptability or versatility
If the thickness of the adhesive layer is increased to improve folding characteristic, then the folding characteristic is improved, but the surface hardness and dent resistance are worsened
Solution Approach 1:
The patent optimizes the thickness parameter of the adhesive layer to a specific range (5 μm to 10 μm) that balances folding characteristic and surface hardness. This thickness optimization resolves the contradiction by finding the optimal value that provides sufficient flexibility without compromising surface hardness.
Data Source
AI summary
A foldable display device, and more particularly, a foldable display device includes a flexible display panel; a support member disposed below the flexible display panel; and a cover member disposed on the flexible display panel, in which the cover member includes a glass disposed on the flexible display panel; a first adhesive layer disposed on the glass; and a barrier film disposed on the first adhesive layer, and a thickness of the barrier film is 30 μm to 70 μm, a thickness of the first adhesive layer is 5 μm to 10 μm, and a modulus of the first adhesive layer is 5×104 Pa to 5×108 Pa.