Optically Clear Adhesive for Foldable Displays
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Solution Overview
Problem
Flexible display devices face deformation issues that are difficult to recover from, affecting their reliability due to the bending and folding processes, leading to buckling phenomena and reduced service life.
Innovation Solution
An optical clear adhesive with a substrate layer and two adhesive material structures, where the substrate layer has a higher deformation recovery rate than the adhesive materials, is applied to the flexible display panel. The adhesive materials are arranged such that the first adhesive material structure with lower modulus and higher tensile properties is on the outer folding side, and the second adhesive material structure with higher modulus and resilience is on the inner folding side, enhancing elastic resilience and reducing buckling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single adhesive material is used in flexible display devices, then the device can be kept simple in structure, but the deformation recovery performance deteriorates due to inability to adapt to different stress conditions in foldable areas
Solution Approach 1:
The adhesive structure is segmented into three distinct layers: a substrate layer and two adhesive material structures (first and second) with different properties. This segmentation allows each layer to perform specific functions - the substrate provides structural support while the two adhesive layers with different moduli handle different stress conditions on the inner and outer folding sides respectively, thereby improving deformation recovery performance without excessive complexity
Solution Approach 2:
Different adhesive material structures are applied to different locations of the flexible display panel. The first adhesive material structure is positioned on the inner folding side where different stress characteristics exist compared to the outer folding side. This local quality approach matches material properties to local stress conditions, enhancing overall reliability and deformation recovery
2Strength
If adhesive materials with high modulus are used to strengthen bonding, then bonding strength is improved, but deformation recovery performance deteriorates due to reduced elastic resilience
Solution Approach 1:
The invention changes the modulus parameter of adhesive materials by using at least two different adhesive material structures with different modulus values. This allows optimization of both bonding strength (using higher modulus materials where needed) and deformation recovery (using lower modulus materials with better elastic resilience in appropriate locations), resolving the contradiction between these two parameters
Solution Approach 2:
The adhesive system uses composite materials comprising multiple adhesive material structures with different mechanical properties. This composite approach enables the system to exhibit both strong bonding capability (from higher modulus components) and good deformation recovery (from lower modulus components with better elasticity), simultaneously achieving both desired properties
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 improves the deformation recovery performance of flexible display devices, reduces buckling issues, and enhances the overall reliability by decoupling stress between the panel and external components, while maintaining transparency and adhesiveness.
Implementation Method 1
a deformation recovery rate of the substrate layer is greater than that of each of the first adhesive material structure and the second adhesive material structure
Data Source
AI summary
The present disclosure discloses an optical clear adhesive and a display device. The display device includes: a flexible display panel having at least one foldable area; and an optical clear adhesive disposed on at least one side of the flexible display panel. The optical clear adhesive includes: a substrate layer, a first adhesive material structure and a second adhesive material structure disposed on two opposite sides of the substrate layer, all of which are transparent materials; a deformation recovery rate of the substrate layer is greater than that of each of the first adhesive material structure and the second adhesive material structure; and in the optical clear adhesive, the first adhesive material structure is closer to an inner folding side of the foldable area of a display panel, and the second adhesive material structure is closer to an outer folding side of the foldable area of the display panel.