OLED Host Material Universality Reduces Melting Pots
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Solution Overview
Problem
The production process of organic electroluminescence display devices is complex and costly due to the need to select and prepare different host and dopant materials for each color of light emission, which complicates the formation of light emitting layers and reduces productivity.
Innovation Solution
The use of a common host material for all colors, with specific dopant and assist dopant materials selected for each color, allows for vapor co-deposition of the host, dopant, and assist dopant materials, simplifying the production process and reducing the number of required melting pots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If different host materials and dopant materials are prepared for each color of light emission, then the light emission quality for each color is optimized, but the production process complexity and device complexity increase significantly
Solution Approach 1:
The patent applies universality by using a single host material (mCP) that serves multiple functions across different color emissions. Instead of preparing different host materials for each color, the same host material is used for red, green, and blue light emitting layers, thereby reducing material preparation complexity while maintaining optimized light emission quality through color-specific dopant selection.
Solution Approach 2:
The patent applies local quality by maintaining uniform host material properties across all color layers while introducing color-specific dopant materials at local levels. Each light emitting layer has the same host material composition but differs in dopant material (e.g., Alq3 for red, BCP for green, Bpy-OXD for blue), allowing optimized light emission for each color without complicating the overall production process.
2Manufacturing precision
If different host materials and dopant materials are prepared for each color of light emission, then the light emission performance for each pixel is optimized, but the productivity decreases due to increased production steps
Solution Approach 1:
The patent improves productivity by making the host material universal across all color layers. The same host material (mCP) is deposited for red, green, and blue layers simultaneously or sequentially without requiring separate preparation steps for each color's host material, thereby reducing production time and increasing manufacturing efficiency while maintaining optimized light emission performance through color-specific dopants.
Solution Approach 2:
The patent merges the host material deposition process across different color layers. Instead of separately preparing and depositing different host materials for each color, the same host material is used and deposited in a unified process, combining multiple production steps into fewer operations, thereby improving productivity without sacrificing light emission performance.
3Manufacturing precision
If multiple different host materials are used for different colors, then the light emission characteristics for each color are optimized, but the number of melting pots and production equipment increases
Solution Approach 1:
The patent reduces the number of melting pots by making the host material universal. A single melting pot containing the host material (mCP) can be used to deposit the host layer for all color pixels (red, green, blue), eliminating the need for separate melting pots for each color's host material, thereby reducing equipment complexity while maintaining color-optimized emission characteristics through dopant variation.
4Manufacturing precision
If different host materials are prepared for each color, then the light emission efficiency for each color is maximized, but the production cost increases
Solution Approach 1:
The patent reduces production cost by using a universal host material across all color layers. Instead of purchasing and preparing different host materials for each color, the same host material (mCP) is used throughout, reducing material procurement costs and simplifying inventory management, while light emission efficiency is maintained through color-specific dopant 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 approach simplifies the production process, improves productivity, and decreases production costs by reducing the number of production steps and melting pots needed, while maintaining efficient light emission across different colors.
Implementation Method 1
An organic electroluminescence element (hereinafter, also referred to as an organic EL element) includes a pair of electrodes and a thin film containing an organic electroluminescence material (hereinafter, also referred to as an 'organic EL material') located between the pair of electrodes. Such an organic EL element emits light as follows.
Implementation Method 2
The use of a common host material for all colors, with specific dopant and assist dopant materials selected for each color, allows for vapor co-deposition of the host, dopant, and assist dopant materials, simplifying the production process and reducing the number of required melting pots.
Data Source
AI summary
An electroluminescence display device includes a first pixel electrode; a second pixel electrode provided in the same layer as the first pixel electrode; a counter electrode provided on the first pixel electrode and the second pixel electrode; a first organic light emitting layer provided between the first pixel electrode and the counter electrode, the first organic light emitting layer emitting light having a first wavelength; and a second organic light emitting layer provided between the second pixel electrode and the counter electrode, the second organic light emitting layer emitting light having a second wavelength. The first light emitting layer contains a host material, a first dopant material and a first assist dopant material; and the second light emitting layer contains the host material, a second dopant material and a second assist dopant material.