Light Extraction Layer with Brush-like Micro-nano Structure
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Solution Overview
Problem
The light extraction efficiency of organic light-emitting devices is currently around 20%, with the remaining light being consumed non-radiatively, indicating a need for improved light extraction techniques.
Innovation Solution
A light-emitting device is designed with a substrate, a light-emitting structure layer, and a first light extraction layer featuring an irregular brush-like micro-nano structure on its light exit surface. Optionally, a second light extraction layer with a different refractive index can be added, and a light extraction mesh film with a sponge pore structure can be incorporated to enhance light extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional flat light extraction layer is used, then the device structure is simple and easy to manufacture, but the light extraction efficiency is low (about 20%) due to high total reflection
Solution Approach 1:
The patent applies curvature by forming a micro-nano structured surface (brush-like structure) on the light extraction layer instead of a flat surface. This curved/micro-structured surface disrupts total internal reflection by creating multiple reflection paths, thereby improving light extraction efficiency while maintaining manufacturing feasibility through established deposition and surface treatment processes
Solution Approach 2:
The patent incorporates a porous or micro-nano structured light extraction layer that utilizes pore structures to scatter and redirect light. The porous structure creates multiple interfaces that reduce total reflection and enhance light extraction, while the structure can be formed through conventional fabrication methods
2Loss of energy
If a micro-nano structured light extraction layer is introduced, then light extraction efficiency is improved by reducing total reflection, but the device structure becomes more complex
Solution Approach 1:
The micro-nano brush-like structure is formed as a surface modification of the light extraction layer rather than a separate complex component. This approach integrates the light extraction function with the structural layer, improving efficiency while minimizing additional device complexity
Solution Approach 2:
The patent optimizes parameters such as the height, density, and distribution of the micro-nano structures to achieve effective light extraction. By carefully controlling these parameters within specific ranges, the patent improves light extraction efficiency while keeping the structure manageable and manufacturable
3Loss of energy
If multiple light extraction layers with different refractive indices are added, then light extraction efficiency is enhanced through improved refraction, but the device structure becomes more complex
Solution Approach 1:
The patent employs composite material structures where the light extraction layer combines materials with different refractive indices to optimize light extraction. The composite structure creates multiple refraction interfaces that enhance light extraction efficiency while maintaining a relatively simple overall device architecture
Solution Approach 2:
The patent introduces intermediate layers with specific refractive indices between the light-emitting layer and the external environment. These intermediary layers act as mediators that facilitate light extraction by optimizing the refraction conditions at each interface, thereby improving overall light extraction efficiency
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 described configuration significantly improves light extraction efficiency by altering reflection and refraction conditions, reducing total reflection, and scattering light in various directions, thereby enhancing the overall luminance and efficiency of the light-emitting device.
Implementation Method 1
light extraction efficiency is determined by luminescence efficiency of a light-emitting function layer in the light-emitting device and phenomena, such as reflection, total reflection
Implementation Method 2
light extraction efficiency is determined by luminescence efficiency of a light-emitting function layer in the light-emitting device and phenomena, such as reflection, total reflection, interference of film layers
Implementation Method 3
scattering light in various directions, thereby enhancing the overall luminance and efficiency of the light-emitting device
Data Source
AI summary
The present application relates to a light-emitting device and a fabrication method thereof, a display device or lighting device, the light-emitting device comprising: a substrate; a light-emitting structure layer disposed on one side of the substrate and comprising a light-emitting function layer; a first light extraction layer disposed on a light exit side of the light-emitting function layer, a light exit surface of the first light extraction layer having an irregular brush-like micro-nano structure.