Flexible Display Device with Dual-Modulus Polymer Layers
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Solution Overview
Problem
Flexible display devices face limitations in folding stability and reliability due to thickness-related issues and bending-induced wrinkles, particularly when increasing thickness.
Innovation Solution
A display device design featuring multiple polymer layers with varying moduli and a window layer, where a first polymer with a high modulus is in direct contact with the display panel, a second polymer with a low modulus is on top of the first, and optionally a third polymer with protrusions, enhancing adhesive force and impact absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the thickness of the flexible display device is increased to improve durability, then strength is improved, but folding stability deteriorates and wrinkles are formed
Solution Approach 1:
The polymer layer is divided into multiple sub-layers with different moduli (first polymer layer with higher modulus, second polymer layer with lower modulus). This segmentation allows each sub-layer to perform its specific function: the first layer provides strength and support, while the second layer provides flexibility and wrinkle prevention during folding.
Solution Approach 2:
Different regions of the polymer layer have different mechanical properties. The first polymer layer has a higher modulus for structural support, while the second polymer layer has a lower modulus for flexibility. This local differentiation of material properties resolves the contradiction between overall strength and folding stability.
2Device complexity
If a single polymer layer is used to simplify the structure, then device complexity is reduced, but adhesive force and impact absorption are insufficient
Solution Approach 1:
The invention uses a composite structure with multiple polymer layers having different moduli. The first polymer layer (higher modulus) provides strong adhesive force to the display panel, while the second polymer layer (lower modulus) provides additional bonding and impact absorption. This composite approach enhances reliability without requiring separate damping layers or adhesive processes.
3Reliability
If multiple polymer layers with different moduli are used to improve impact absorption, then reliability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The invention specifies particular modulus ranges for each polymer layer (first layer: 100-1000 MPa, second layer: 10-100 MPa) to optimize impact absorption while maintaining manufacturability. By defining clear parameter ranges, the invention balances improved reliability with practical manufacturing precision requirements.
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
Improves stability and reliability by effectively absorbing and dispersing impacts, reducing thickness, and eliminating the need for a damping layer and adhesive process, thereby enhancing foldability and durability.
Implementation Method 1
a first polymer layer disposed on the display panel, in direct contact with the display panel, and having a first modulus, a second polymer layer disposed on the first polymer layer, in direct contact with the first polymer layer, and having a second modulus less than the first modulus
Implementation Method 2
an adhesive force of the first polymer may be greater than an adhesive force of the second polymer
Data Source
AI summary
A display device includes a display panel, a first polymer disposed on the display panel, in direct contact with the display panel, and having a first modulus, a second polymer disposed on the first polymer, in direct contact with the first polymer, and having a second modulus less than the first modulus, and a window layer disposed on the second polymer.