Nanometer Metal Layer for OLED Light Extraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Organic light emitting display devices suffer from low external light efficiency due to significant light loss through total reflection as light passes through their multilayer laminated structure, necessitating a reduction in internal light loss to enhance overall light emitting efficiency.
Innovation Solution
A metal layer with a nanometer thickness, featuring holes or dispersed metal dots, is formed on a protective layer to alter the light path and reduce total reflection, increasing the amount of light emitted externally. The metal layer is typically made of silver or aluminum and has a thickness between 0.1 nm and 3 nm, with hole or dot diameters ranging from 10 nm to 500 nm and distances from 30 nm to 1,000 nm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multilayer laminated structure is used to protect internal components, then device protection and structural integrity are improved, but light loss due to total reflection increases and light emitting efficiency deteriorates
Solution Approach 1:
The protective layer is segmented by forming holes or dispersed metal dots within it, creating multiple interfaces that disrupt total reflection pathways. This segmentation allows light to escape through the holes and metal dot interfaces while maintaining the protective function of the layer material itself.
Solution Approach 2:
Metal layers with nanometer thickness are introduced as intermediary elements between the protective layer and the external environment. These metal layers serve dual functions: maintaining structural protection while providing optical pathways through their unique nanoscale properties that reduce total reflection.
2Loss of energy
If a thick metal layer is formed on the protective layer, then light extraction efficiency is improved, but device thickness and manufacturing complexity increase
Solution Approach 1:
The metal layer thickness is optimized to a specific nanometer range (0.1-3 nm), which is thin enough to maintain device compactness but thick enough to provide the necessary optical extraction enhancement. This parameter optimization resolves the contradiction between extraction efficiency and device thickness.
Solution Approach 2:
Instead of forming a continuous thick metal layer, metal dots or holes are distributed locally throughout the protective layer. This local quality approach provides light extraction enhancement at specific points while maintaining overall device thinness and reducing material usage.
3Loss of energy
If holes are formed in the metal layer to increase light extraction, then light emitting efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
Rather than requiring precise control of every hole's position and size, the invention uses a statistical distribution approach where numerous holes or metal dots are formed with varied positions and sizes. The collective effect of many imperfectly positioned features achieves the desired light extraction enhancement without demanding extreme manufacturing precision for each individual feature.
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 enhances light extraction efficiency by deviating total-reflected light, increasing the amount of light emitted outside and improving overall light emitting efficiency by up to 25% compared to devices without the nanohole thin film structure.
Implementation Method 1
the light generated from the emission layer is lost in the device due to total reflection and the like
Implementation Method 2
A metal layer having a nanometer thickness, featuring holes or dispersed metal dots, is formed on a protective layer to alter the light path and reduce total reflection
Data Source
AI summary
Disclosed is an organic light emitting display device improving light efficiency by forming a metal layer having a nanometer thickness on a protective layer formed in order to protect the organic light emitting diode.