Flexible Display Window Member With Hardness Gradient
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Solution Overview
Problem
Existing flexible display devices face challenges in achieving a balance between flexibility and hardness, and are susceptible to imprint defects, which affect their durability and functionality, especially when folded or rolled.
Innovation Solution
A flexible display device is designed with a window member comprising a base film and a polymer layer with varying hardness regions, where a cross-linkable polymer layer is formed with different hardness parts using high energy ion-beam irradiation, and optionally includes anti-finger, self-healing, and anti-reflection layers, along with a touch panel and optically clear adhesive members to enhance durability and prevent imprint defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a uniform hardness polymer layer is used, then the surface hardness is improved to prevent external damage, but the flexibility and foldability deteriorate
Solution Approach 1:
The polymer layer is divided into different regions with different hardness properties. The first region has higher hardness to provide scratch resistance and prevent external damage, while the second region has lower hardness to enable flexibility and foldability. This local differentiation of material properties resolves the contradiction between surface hardness and flexibility.
Solution Approach 2:
The polymer layer is segmented into multiple regions (first region and second region) with distinct hardness characteristics. This segmentation allows each region to perform its specific function - the harder first region for protection and the softer second region for flexibility - thereby resolving the contradiction between hardness and adaptability.
2Adaptability or versatility
If the polymer layer is made softer to improve flexibility, then the foldability is improved, but the resistance to imprint defects deteriorates
Solution Approach 1:
Different regions of the polymer layer are assigned different hardness properties to address different functional requirements. The first region with higher hardness resists imprint defects from external pressure, while the second region with lower hardness provides foldability. This local quality differentiation resolves the contradiction between foldability and imprint defect resistance.
3Strength
If the entire polymer layer is irradiated with high energy ion-beam, then the surface hardness is improved, but the flexibility in foldable regions deteriorates
Solution Approach 1:
The ion-beam irradiation is applied selectively to different regions to create local quality differences. The first region receives ion-beam irradiation to achieve high hardness and scratch resistance, while the second region is excluded from irradiation to maintain flexibility. This selective local treatment resolves the contradiction between overall surface hardness and regional flexibility.
Solution Approach 2:
The irradiation process is segmented into different zones - the first region is irradiated with high energy ion-beam while the second region is protected from irradiation. This spatial segmentation of the irradiation process creates the desired hardness gradient that resolves the contradiction between hardness improvement and flexibility preservation.
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 provides improved flexibility and hardness to the display device, reducing the likelihood of imprint defects and enabling the device to be folded or rolled without breaking, while maintaining high surface hardness to prevent external damage.
Implementation Method 1
partially irradiating the cross-linkable polymer layer with a high energy ion-beam to form a polymer layer comprising a first part and a plurality of second parts having lower hardness than that of the first part
Implementation Method 2
The polymer layer may include a cross-linkable polymer
Data Source
AI summary
A flexible display device includes: a display panel to generate an image; and a window member on the display panel, the window member including: a base film; and a polymer layer including a first part and a plurality of second parts having lower hardness than that of the first part.