Cover Window with Silicone Resin Layers for Foldable Displays
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Solution Overview
Problem
Foldable organic light-emitting display devices face challenges in impact resistance due to the use of plastic films for cover windows, which have lower rigidity compared to conventional glass substrates.
Innovation Solution
A cover window design featuring a non-folding area with high rigidity and a folding area with flexibility, utilizing a soft portion made of a first silicone resin and a hard portion and hard coating layer composed of a mixture of second and third silicone resins, which are cured to provide enhanced hardness and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a plastic film is used for the cover window to enable folding, then flexibility and portability are improved, but impact resistance and rigidity deteriorate
Solution Approach 1:
The cover window is divided into a folding area with flexible properties and a non-folding area with hard properties. The flexible area contains only the flexible resin layer to enable bending, while the non-folding area includes rigid resin layers for impact resistance. This local differentiation allows the cover window to simultaneously achieve folding capability and impact protection.
Solution Approach 2:
The cover window uses a composite structure with multiple resin layers having different mechanical properties. The flexible resin layer (first resin) provides bending capability, while the rigid resin layers (second and third resins) provide hardness and impact resistance. The combination of materials with complementary properties resolves the contradiction between flexibility and strength.
2Strength
If a glass substrate is used for the cover window, then rigidity and impact resistance are improved, but flexibility and folding capability deteriorate
Solution Approach 1:
The rigid resin layers are positioned only in the non-folding area where high rigidity is required for display protection and user interaction. The folding area contains only the flexible resin layer, allowing the display to be bent without resistance from rigid materials. This spatial separation of rigid and flexible properties enables both rigidity and folding capability.
Solution Approach 2:
The composite structure combines flexible resin and rigid resin in specific spatial arrangements. The flexible resin layer enables folding throughout the structure, while the rigid resin layers are strategically placed only where needed for structural support and impact resistance, allowing the overall system to achieve both flexibility and rigidity.
3Adaptability or versatility
If different materials are used for folding and non-folding areas, then functional requirements are met, but manufacturing complexity and boundary visibility increase
Solution Approach 1:
Both the flexible resin layer and rigid resin layers use resin materials with similar optical properties and chemical composition. This homogeneity in material type ensures that the refractive indices are matched, making the boundaries between flexible and rigid areas invisible. The similar chemical nature also simplifies the manufacturing process by allowing both layers to be formed using compatible methods.
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 increases impact resistance for both folding and non-folding areas, prevents visibility of the boundary between materials, and simplifies manufacturing while maintaining excellent folding characteristics and thermal stability, reducing the risk of cracks and manufacturing costs.
Implementation Method 1
a soft portion located to correspond to the folding area, the soft portion being flexible
Implementation Method 2
a hard coating layer configured to cover the hard portion and the soft portion. The hard portion and the hard coating layer may include a mixture of a second silicone resin and a third silicone resin
Implementation Method 3
performing ultraviolet curing and thermosetting
Implementation Method 4
may increase impact resistance of both the folding area and the non-folding area
Data Source
AI summary
Disclosed are a cover window in which both a folding area and a non-folding area are formed using the same kind of material, thereby matching the indices of refraction thereof with each other, having the same heat resistance, and ensuring easy surface hard coating thereof, and a display device using the same. The cover window, having at least one folding area and a non-folding area, includes a hard portion located to correspond to the non-folding area, a soft portion located to correspond to the folding area, the soft portion being flexible, and a hard coating layer configured to cover the hard portion and the soft portion.