Flexible Display Layered Adhesive for Light Output and Durability
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Solution Overview
Problem
Display devices exhibit varying light output efficiencies based on the direction of light emission, and there is a need for improved optical properties and durability, particularly in flexible and foldable devices.
Innovation Solution
A display device with a layered adhesive structure comprising a first adhesive layer with a high refractive index and a second adhesive layer with a lower refractive index, using aromatic and aliphatic (meth)acrylate compounds, along with fillers like zirconium oxide and titanium oxide, to enhance optical properties and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a single adhesive layer is used, then the structure is simple, but the optical properties and shock absorption are insufficient
Solution Approach 1:
The adhesive layer is divided into two distinct layers: a first adhesive layer with high refractive index (1.55-1.70) for optical performance, and a second adhesive layer with low refractive index (1.45-1.48) for shock absorption. Each layer performs its specific function, resolving the contradiction between optical properties and structural simplicity.
Solution Approach 2:
The invention uses composite adhesive materials with different refractive indices arranged in a layered structure. The first adhesive layer contains aromatic (meth)acrylate compounds with high refractive index, while the second adhesive layer contains aliphatic (meth)acrylate compounds with low refractive index, creating a composite structure that achieves both optical enhancement and mechanical flexibility.
2Illumination intensity
If a high refractive index adhesive layer is used to improve light output, then optical properties improve, but the adhesive becomes brittle and durability decreases
Solution Approach 1:
The adhesive system is segmented into two functional layers: the first layer provides high refractive index for light extraction, while the second layer provides low refractive index and high flexibility for shock absorption. This segmentation allows each layer to optimize its specific function without compromising the other.
Solution Approach 2:
The invention changes the refractive index parameter between the two adhesive layers to create functional differentiation. The first layer has refractive index 1.55-1.70 (high) for optical performance, while the second layer has refractive index 1.45-1.48 (low) for mechanical flexibility and shock absorption, resolving the contradiction between optical properties and durability.
3Illumination intensity
If aromatic (meth)acrylate compounds are used for high refractive index, then optical properties improve, but the material becomes more rigid and flexibility decreases
Solution Approach 1:
Different regions of the adhesive structure have different material compositions: the first adhesive layer uses aromatic (meth)acrylate compounds with high refractive index for optical enhancement, while the second adhesive layer uses aliphatic (meth)acrylate compounds with low refractive index for flexibility. Each region has the local quality needed for its specific function.
Solution Approach 2:
The invention creates a composite adhesive system combining aromatic and aliphatic (meth)acrylate compounds in separate layers. The aromatic compounds provide high refractive index in the first layer, while the aliphatic compounds provide low refractive index and high flexibility in the second layer, achieving both optical performance and durability.
4Reliability
If aliphatic (meth)acrylate compounds are used for flexibility, then durability improves, but the refractive index is too low for optimal optical properties
Solution Approach 1:
The adhesive system is segmented such that the first layer handles optical functions with aromatic (meth)acrylate compounds, while the second layer handles mechanical functions with aliphatic (meth)acrylate compounds. This segmentation allows each material to optimize its inherent properties without compromise.
Solution Approach 2:
The aliphatic (meth)acrylate compound in the second adhesive layer provides excessive flexibility and shock absorption relative to its refractive index, which is acceptable because its primary function is mechanical protection rather than optical enhancement. The optical function is adequately performed by the first layer.
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 layered adhesive structure improves light output efficiency and durability by absorbing external shocks, ensuring excellent optical properties and flexibility in display devices.
Implementation Method 1
The adhesive layer may include a first adhesive layer including a first base resin and having a first refractive index; and a second adhesive layer disposed on the first adhesive layer, the second adhesive layer including a second base resin and having a second refractive index lower than the first refractive index.
Implementation Method 2
a display device having excellent optical properties as well as having low modulus properties by securing fluidity absorbing external shocks
Data Source
AI summary
A display device includes a display panel including a light emitting region and a peripheral region adjacent to the light emitting region; an organic layer disposed on the display panel and having an opening that overlaps the light emitting region; and an adhesive layer disposed on the organic layer. The adhesive layer includes a first adhesive layer including a first base resin and having a first refractive index; and a second adhesive layer disposed on the first adhesive layer and having a second refractive index less than the first refractive index.