Flexible Display Neutral Surface Optimization
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Solution Overview
Problem
Existing flexible display devices with multi-layer structures face challenges in folding without delamination, as the radius of curvature decreases, leading to separation of layers, which hinders the application of large screens in foldable mobile devices.
Innovation Solution
A flexible display device with a multi-layer structure is designed, where the neutral surface's radius of curvature is optimized by determining the elastic modulus and thickness of adhesive and panel layers, ensuring the neutral surface is between the display and protective panels, and the adhesive layers are positioned to distribute strain evenly, preventing delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the flexible display device is folded with a small radius of curvature, then the device can be compact and portable, but delamination occurs between layers
Solution Approach 1:
The patent changes the physical parameters of the adhesive layers by optimizing their thickness and elastic modulus to match the mechanical properties of adjacent panel layers. This parameter optimization allows the multi-layer structure to withstand small radius of curvature folding without delamination, resolving the contradiction between compact folded size and layer adhesion reliability.
Solution Approach 2:
The patent employs composite material design by creating a multi-layer structure where each layer (display panel, touch panel, protective panel, and adhesive layers) has specifically tailored mechanical properties. The adhesive layers are designed as composite interfaces with optimized elastic moduli between 0.1-10 GPa, enabling the composite structure to flex without interlayer separation while maintaining structural integrity during folding.
2Reliability
If the adhesive layers and panel layers have optimized elastic modulus and thickness, then delamination is reduced, but the manufacturing complexity increases
Solution Approach 1:
The patent establishes specific parameter ranges for adhesive layer thickness (10-100 micrometers) and elastic modulus (0.1-10 GPa) to optimize layer adhesion. By defining these parameter ranges, the patent reduces manufacturing complexity through standardized specifications while maintaining high reliability and preventing delamination in the multi-layer flexible display structure.
3Area of stationary object
If a large display device is applied to a foldable mobile device, then the screen size is increased, but the device becomes harder to fold without delamination
Solution Approach 1:
The patent optimizes the elastic modulus and thickness parameters of adhesive and panel layers to enable large-area flexible displays to fold precisely without delamination. The optimized parameters ensure that stress is evenly distributed across the large display area during folding, achieving both large screen area and high folding precision.
Solution Approach 2:
The patent uses composite material design with multiple layers having different mechanical properties to create a flexible display structure that can be folded. The composite structure includes display panels, touch panels, protective panels, and adhesive layers with optimized elastic moduli, enabling large screens to maintain structural integrity during folding operations.
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 the risk of delamination, allowing the flexible display device to fold without layer separation, enabling the use of larger screens in foldable electronic devices while maintaining structural integrity.
Implementation Method 1
the layers are plastic-deformed to reduce strain and prevent delamination
Data Source
AI summary
A flexible display device that may fold so that a neutral surface has a radius of curvature is provided. The flexible display device includes a plurality of panel layers that are sequentially stacked on one another and comprise a display panel layer configured to display an image and a transparent protective panel layer; and adhesive layers that sequentially adhere the plurality of panel layers to one another. An elastic modulus and a thickness of each of the adhesive layers and the plurality of panel layers are determined so that a neutral surface is located on a layer other than the display panel layer.