LVT Inorganic Encapsulation for Flexible OLED Stress Management
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Solution Overview
Problem
Organic light emitting display devices are vulnerable to external influences such as oxygen and moisture, requiring effective encapsulation to maintain performance and longevity, especially for thin and flexible forms which existing encapsulation methods have not adequately addressed.
Innovation Solution
An organic light emitting display device is designed with a substrate, an organic light emitting unit, and at least one inorganic layer containing low temperature viscosity transition (LVT) material, along with an adhesive layer to provide enhanced encapsulation. The LVT inorganic material has a viscosity transition temperature lower than the denaturation temperature of the organic light emitting unit, and the adhesive layer has a coefficient of thermal expansion that compensates for stress between layers, ensuring effective protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional encapsulation methods are used for thin and flexible organic light emitting displays, then the device structure can be simplified, but the encapsulation performance against moisture and oxygen is insufficient
Solution Approach 1:
The patent employs a composite encapsulation structure combining organic adhesive layers with inorganic encapsulation layers. The adhesive layer contains specific functional materials that provide both adhesion and barrier properties, while the inorganic layers provide complementary protection. This composite approach achieves superior encapsulation performance against moisture and oxygen compared to single-material conventional methods, while maintaining a manageable structural complexity through systematic layer integration.
Solution Approach 2:
The patent utilizes thin-film encapsulation architecture where multiple nanometer-to-micrometer scale layers are deposited to provide robust protection. The flexible substrate and thin encapsulation layers work together to maintain flexibility while providing effective barrier properties. This approach enables thin and flexible display devices to achieve reliable encapsulation without requiring bulky protective structures.
2Strength
If the adhesive layer has high adhesion strength to ensure layer bonding, then layer delamination is prevented, but thermal stress during manufacturing and operation increases
Solution Approach 1:
The patent carefully controls the thickness parameter of the adhesive layer, optimizing it to balance adhesion strength and stress management. By adjusting this critical parameter, the adhesive layer provides sufficient bonding between layers while minimizing thermal stress accumulation during manufacturing processes and device operation. This parameter optimization resolves the contradiction between strong adhesion and stress reduction.
Solution Approach 2:
The adhesive layer is designed with specific thermal expansion characteristics that compensate for differential thermal expansion between the flexible substrate and inorganic encapsulation layers. This thermal expansion matching reduces thermal stress during temperature variations in manufacturing and operation, while maintaining adequate adhesion strength to prevent delamination.
3Stability of the object's composition
If the inorganic layer uses high melting point material to ensure thermal stability, then thermal resistance is improved, but the manufacturing process temperature range is restricted
Solution Approach 1:
The patent divides the encapsulation structure into multiple functional layers with different material properties. The inorganic encapsulation layers use materials with high thermal stability for protection, while separate organic adhesive and barrier layers provide flexibility in manufacturing. This segmentation allows each layer to be optimized for its specific function, enabling high thermal stability where needed while maintaining manufacturing flexibility through the overall multi-layer architecture.
Solution Approach 2:
The adhesive layer serves as an intermediary between the flexible substrate and the high-melting-point inorganic encapsulation layers. This intermediary layer accommodates thermal expansion differences and allows the inorganic layers to be deposited at optimal temperatures without compromising the flexibility of the overall device or restricting manufacturing process choices.
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 robust encapsulation against moisture and oxygen, maintaining the integrity and performance of the organic light emitting display device, particularly for thin and flexible forms, by using LVT inorganic materials and strategically positioned adhesive layers to manage thermal expansion and stress.
Implementation Method 1
at least one inorganic layer, which encapsulates the organic light emitting unit and contains a low temperature viscosity transition (LVT) inorganic material
Implementation Method 2
the adhesive layer has a coefficient of thermal expansion (CTE) that compensates for stress between layers
Data Source
AI summary
In an aspect, an organic light emitting display device is provided. The organic light emitting display device may include a substrate; an organic light emitting unit arranged on the substrate; at least one inorganic layer, which encapsulates the organic light emitting unit and contains a low temperature viscosity transition (LVT) inorganic material; and at least one adhesive layer arranged between the organic light emitting unit and the inorganic layer.