Wavy Light-Extracting Layer for OLED Optical Loss Reduction
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Solution Overview
Problem
Organic light emitting devices (OLEDs) suffer from low light extraction efficiency due to the different refractive indices of their layers, resulting in only 20% of light being extracted, with the rest being reflected and refracted back into the device.
Innovation Solution
Incorporating a transparent light extracting component with a wavy shape on the light outputting side, comprising a light outputting layer, a shape preserving layer, and a planarization layer, where the surfaces of these layers have complementary wavy patterns to enhance light extraction, with materials like silicon oxide or silicon nitride used for the shape preserving layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a flat light outputting surface is used, then the device structure is simple and easy to manufacture, but light extraction efficiency is low (only 20% extraction due to reflection and refraction at interfaces)
Solution Approach 1:
The patent applies curvature by forming a wavy shape on the light outputting surface of the light emitting layer. This wavy structure consists of undulating surfaces that redirect light paths, reducing reflection and refraction losses at interfaces. The curved geometry transforms the flat surface into a light-scattering structure that enhances light extraction efficiency while maintaining manufacturing feasibility through coating process adjustments
2Loss of energy
If a wavy shape is formed on the light outputting layer, then light extraction efficiency is improved, but the device structure becomes more complex
Solution Approach 1:
The patent applies local quality by introducing the wavy shape only at the light outputting surface of the light emitting layer, while keeping other device layers flat and unchanged. This localized modification targets the specific interface where light extraction occurs, enhancing performance without unnecessarily complicating the overall device structure. The wavy pattern is confined to the functional region needed for light extraction improvement
3Loss of energy
If the coating speed is adjusted to form a wavy shape, then light extraction efficiency is enhanced, but the manufacturing precision control becomes more difficult
Solution Approach 1:
The patent applies dynamics by adjusting the coating speed during the manufacturing process to dynamically form the wavy shape on the light outputting surface. The coating head moves at variable speeds, creating controlled undulations in the light emitting layer. This dynamic approach allows the wavy structure to be formed during normal coating operations without requiring additional precision control equipment or complex manufacturing steps
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 wavy interfaces reduce optical loss by minimizing light reflection and improve light extraction efficiency, allowing more light to be outputted, thereby enhancing the overall performance of OLEDs.
Implementation Method 1
Because refractive indices of the layers are different, the light transmits at part of the interface of the device, reflection and refraction further occur
Implementation Method 2
Because refractive indices of the layers are different, the light transmits at part of the interface of the device, reflection and refraction further occur
Data Source
AI summary
An organic light emitting device and a method of manufacturing an organic light emitting device. The organic light emitting device includes a transparent light extracting component including a light outputting layer on a light outputting side, and at least one surface of the light outputting layer has a first wavy shape.