OLED Light Extraction via Refractive Index Gradient
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Solution Overview
Problem
The challenge in the field of OLED display panels is to improve light-emitting efficiency and light extraction efficiency, which is crucial for enhancing the performance of these devices.
Innovation Solution
The solution involves an organic light-emitting display panel structure with a specific layer configuration, including an anode, a cathode, and an organic functional layer with a hole transmission region, a light-emitting layer, and an electron transmission region, where the refractive indices of these layers are optimized to ensure that light is emitted close to the normal direction, increasing the amount of extracted light by refracting it into a denser medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the refractive index of the light-emitting layer is increased to improve light extraction efficiency, then more light can be extracted, but the light emission direction becomes more divergent and less controllable
Solution Approach 1:
The patent optimizes the refractive index parameter of the light-emitting layer to be lower than that of adjacent layers (hole transmission layer and electron transmission layer), creating a specific refractive index gradient that controls light extraction efficiency while maintaining directional emission characteristics
Solution Approach 2:
The patent applies different refractive index characteristics to different regions of the OLED structure - the light-emitting layer has a lower refractive index than the adjacent transport layers, creating localized optical property differences that enhance light extraction at the emission interface while preserving overall directional control
2Ease of manufacture
If the OLED structure is simplified to reduce manufacturing complexity, then production cost decreases, but light extraction efficiency deteriorates
Solution Approach 1:
The hole transmission layer and electron transmission layer serve dual functions: they perform their primary charge transport roles while simultaneously acting as optical layers with higher refractive indices than the light-emitting layer, thereby enhancing light extraction efficiency without adding separate dedicated layers
Solution Approach 2:
The patent combines the optical function of light extraction enhancement with the existing charge transport layers, merging multiple functions into the same structural elements to avoid increasing manufacturing complexity while improving light extraction performance
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 enhances light extraction efficiency by ensuring that more light is emitted in a direction that can be utilized, thereby improving the overall performance of OLED display panels.
Implementation Method 1
With respect to visible light having a certain wavelength, a refractive index of the light-emitting layer is less than a refractive index of the electron transmission region, and the refractive index of the light-emitting layer is less than a refractive index of the hole transmission region
Data Source
AI summary
Provided are an organic light-emitting display panel and a display device, for improving the light extraction efficiency of OLED display panel. The organic light-emitting display panel includes an array substrate having a plurality of driving elements, and a plurality of organic light-emitting components. Each light-emitting component includes an anode, a cathode and an organic functional layer arranged between the anode and the cathode. The organic functional layer includes a hole transmission region, a light-emitting layer, and an electron transmission region stacked in a sequence from the anode to the cathode. With respect to visible light having a certain wavelength, a refractive index of the light-emitting layer is less than a refractive index of the electron transmission region, and the refractive index of the light-emitting layer is less than a refractive index of the hole transmission region. The above organic light-emitting display panel is applicable to the display device.