Nanopatterned Metal Reflection Layer for OLED Light Extraction
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Solution Overview
Problem
Current organic light emitting devices (OLEDs) face challenges in achieving high color conversion efficiency and luminous efficiency due to limitations in extracting light effectively, particularly in utilizing the microcavity effect and surface plasmon modes.
Innovation Solution
A light emitting device is designed with a first metal reflection layer featuring a phase modulation surface with a meta structure of periodically arranged nanopatterns, a color conversion layer containing photoluminescent material, and a microcavity formed between the metal reflection layer and a second electrode, where the nanopatterns' size and pitch determine the resonance wavelength, enhancing light conversion efficiency through magnetic resonance and surface plasmon effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional reflective metal layer is used in OLEDs, then the device structure is simple, but the light extraction efficiency is low due to waveguided mode limitations and surface plasmon polariton mode suppression
Solution Approach 1:
The patent applies parameter changes by modifying the reflective metal layer's surface properties through nanopattern formation. The reflective layer transitions from a flat surface to a nanostructured surface with specific geometric parameters (nanopillar diameter, height, spacing), which changes the optical parameters including phase delay and resonance wavelength to enhance light extraction efficiency
Solution Approach 2:
The patent introduces another dimension by adding vertical nanopatterns to the reflective metal layer surface. This transforms the two-dimensional flat reflective surface into a three-dimensional nanostructured surface, creating microcavity effects and enabling magnetic resonance that enhance light extraction in the vertical dimension
2Productivity
If a microcavity effect is implemented to enhance light extraction, then the luminous efficiency improves, but the device complexity increases due to additional layers and structures
Solution Approach 1:
The patent merges the microcavity structure with the existing reflective electrode layer. Instead of adding a separate microcavity component, the nanopatterned reflective layer itself forms the microcavity structure, combining the reflective function and the light extraction enhancement function into a single integrated component
Solution Approach 2:
The nanopatterned reflective metal layer serves multiple functions simultaneously: it maintains the reflective function for cavity formation, provides phase modulation through nanopatterns, enables magnetic resonance for enhanced extraction, and creates surface plasmon effects. This multi-functionality reduces the need for additional separate components
3Productivity
If nanopatterns are added to the reflective metal layer to enhance extraction, then the color conversion efficiency improves, but the manufacturing precision requirements increase
Solution Approach 1:
The patent optimizes nanopattern parameters (diameter, height, spacing) to achieve desired optical performance. By carefully selecting these parameters, the design achieves enhanced color conversion efficiency while maintaining manufacturability through established nanofabrication techniques
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 solution significantly improves color conversion efficiency and luminous efficiency by optimizing the resonance wavelength and phase delay, allowing for enhanced emission of specific colors, applicable in various display devices and lighting applications.
Implementation Method 1
a first metal reflection layer including a phase modulation surface configured to magnetically resonate incident light
Implementation Method 2
a color conversion layer provided on the phase modulation surface of the first metal reflection layer and including a photoluminescent material
Implementation Method 3
the first metal reflection layer and the second electrode form a microcavity having a resonance wavelength determined by an optical distance between the first metal reflection layer and the second electrode
Implementation Method 4
the phase delay of light reflected from the first metal reflection layer is determined by a size and pitch of the nanopatterns
Data Source
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AI summary
Provided a light emitting device including a first metal reflection layer including a phase modulation surface configured to magnetically resonate incident light, a color conversion layer provided on the phase modulation surface of the first metal reflection layer and including a photoluminescent material, a first electrode provided on the color conversion layer opposite to the first metal reflection layer, a white organic light emitting layer provided on the first electrode opposite to the color conversion layer, and a second electrode provided on the white organic light emitting layer opposite to the first electrode.