OLED Light Extraction Layer Sawtooth Structure
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Solution Overview
Problem
Traditional OLED light emitting devices suffer from low light-emitting efficiency due to significant light loss caused by reflection and refraction between the glass substrate and the air interface, resulting in insufficient brightness.
Innovation Solution
The implementation of a light extraction layer with a specific refractive index structure, comprising multiple material layers with sawtooth portions and defined angles, positioned between the anode and substrate, to optimize light transmission and enhance light output from the emitting surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a traditional OLED structure with glass substrate and flat interfaces is used, then the device structure is simple and easy to manufacture, but light emission efficiency is low due to reflection and refraction losses at interfaces
Solution Approach 1:
The patent transforms the flat two-dimensional interface between substrate and light extraction layer into a three-dimensional sawtooth structure. This dimensional change creates multiple light extraction paths and interfaces, increasing the overall light emission efficiency by reducing reflection and refraction losses through the complex geometric configuration of the sawtooth portions.
Solution Approach 2:
The patent optimizes specific parameters of the light extraction layer including the refractive index (set between 1.30-1.60), the bottom angle of sawtooth portions (30°-60°), and the thickness of the light extraction layer (5-20 μm). By carefully controlling these parameters, the device achieves maximum light extraction efficiency while maintaining manufacturability.
2Loss of energy
If a light extraction layer with sawtooth portions and multiple material layers is introduced, then light emission efficiency is improved, but the device structure becomes more complex
Solution Approach 1:
The patent applies local quality by creating sawtooth portions only in the light extraction layer adjacent to the substrate, while other layers maintain their conventional structures. This localized modification focuses the complexity only where it is most effective for light extraction, rather than complicating the entire device structure uniformly.
Solution Approach 2:
The patent employs a composite light extraction layer consisting of multiple material layers with different refractive indices (first material layer with n=1.30-1.50, second material layer with n=1.40-1.60). This composite structure enhances light extraction through refractive index matching while managing the structural complexity through systematic material selection.
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 increases light-emitting efficiency by redirecting and maximizing light output from the OLED device, improving brightness and reducing side emission, thereby addressing the limitations of traditional OLED devices.
Implementation Method 1
an index of refraction (nA) of the first material layer, that (nsubstrate) of the substrate, and that (nB) of the second material layer satisfy a condition: nA>nsubstrate>nB
Implementation Method 2
most of the light A1 cannot output an emitting surface of the OLED light emitting device and emit to a side of the emitting surface due to the influence of the reflection and the refraction between the glass substrate 10 and the surface layer of the air area
Data Source
AI summary
An OLED light emitting device and a display device are provided. The OLED light emitting device has a cathode, a light-emitting layer, an anode, a substrate, and a light extraction layer; the light extraction layer at least has a first material layer and a second material layer; a first contact surface of the first material layer and a second contact surface of the second material layer contact each other; a longitudinal section of the first contact surface and that of the second contact surface have sawtooth portions fitted with each other; nA>nsubstrate>nB.