OLED Light-Coupling Layer Group for Efficiency
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Solution Overview
Problem
Existing organic light-emitting display panels face limitations in light-emission efficiency due to the micro-cavity structure's angle-dependent characteristics, which result in varying brightness and color when viewed from different angles, and the improvement using a single high-refractive-index light-coupling layer is insufficient.
Innovation Solution
The introduction of a light-coupling layer group with at least one stacked layer, where the first light-coupling layer has a higher refractive index than the second light-coupling layer, arranged such that the high-refractive-index layer is closer to the organic light-emitting material layer, and the low-refractive-index layer is farther away, enhancing light emission efficiency by adjusting the refractive indices and optical path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a single high-refractive-index light-coupling layer is used, then light transmittance is improved, but light-emission efficiency improvement is limited
Solution Approach 1:
The light-coupling layer is segmented into multiple stacked layers with different refractive indices. The first light-coupling layer has a higher refractive index than the second light-coupling layer, creating a gradient structure that progressively optimizes light extraction at each interface, thereby significantly improving light-emission efficiency beyond what a single layer can achieve
Solution Approach 2:
Different regions of the light-coupling structure are assigned different refractive indices tailored to their specific functions. The first light-coupling layer with higher refractive index is positioned closer to the organic light-emitting material layer to maximize light extraction, while the second light-coupling layer with lower refractive index is positioned farther away to optimize light transmission to the viewer
2Illumination intensity
If a light-coupling layer is added to improve light transmittance, then device structure becomes more complex
Solution Approach 1:
The light-coupling function is extracted as a separate, dedicated component (light-coupling layer group) distinct from the OLED device itself. This modular approach allows optimization of light coupling without complicating the core OLED structure, and the light-coupling layer group can be independently designed and manufactured
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
This configuration significantly improves light-emission efficiency by reducing total internal reflection and absorption, leading to higher peak intensities and better light transmission, thus overcoming the limitations of existing technologies.
Implementation Method 1
This configuration significantly improves light-emission efficiency by reducing total internal reflection and absorption
Implementation Method 2
A refractive index of the first light-coupling layer is larger than a refractive index of the second light-coupling layer in the at least one light-coupling stacked layer
Implementation Method 3
enhancing light emission efficiency by adjusting the refractive indices and optical path
Data Source
AI summary
An organic light-emitting display panel and a display device are provided. The light-emitting display panel includes a first electrode layer including a reflective electrode, and a second electrode layer arranged opposite to the first electrode layer and including a semi-reflective electrode. The light-emitting display panel also includes a light-emitting material layer between the two electrode layers. The second electrode layer has a first side facing the light-emitting material layer and an opposing second side. Further, the light-emitting display panel includes a light-coupling layer group disposed on the opposing second side of the second electrode layer. The light-coupling layer group includes at least one light-coupling stacked layer including a first light-coupling layer arranged close to the second electrode layer and a second light-coupling layer arranged far away from the second electrode layer. A refractive index of the first light-coupling layer is larger than a refractive index of the second light-coupling layer.