Organic EL Device Multiple Light Emitting Layers Spraying
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Solution Overview
Problem
Existing organic electroluminescence devices face challenges in achieving high luminous efficiency, durability, and color reproducibility while maintaining low manufacturing costs, particularly due to limitations in the vapor deposition method and single-layer light emitting structures.
Innovation Solution
The development of an organic electroluminescence device with multiple light emitting layers formed using a spraying method, where at least one layer is coated as a solution or dispersion in an organic solvent, allowing for better bonding and reduced manufacturing costs, and incorporating different light emitting materials in separate layers to enhance color reproduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vapor deposition method is used to form light emitting layers, then luminous efficiency and durability are improved, but manufacturing cost and energy consumption increase
Solution Approach 1:
The invention changes the physical state parameter of the light emitting materials from vapor phase (in vapor deposition) to solution phase (in coating), using organic solvents to dissolve or disperse the materials. This parameter change enables the use of low-cost coating equipment instead of expensive vapor deposition apparatus while maintaining layer formation quality
Solution Approach 2:
The invention uses liquid coating methods where light emitting materials dissolved or dispersed in organic solvents are coated onto substrates using hydraulic/coating techniques. This replaces the pneumatic/vapor-based deposition method, reducing equipment cost and energy consumption while achieving comparable layer quality
2Ease of manufacture
If coating method with organic solvents is used to form light emitting layers, then manufacturing cost is reduced, but luminous efficiency and durability deteriorate
Solution Approach 1:
The invention divides the light emitting function into multiple separate light emitting layers, each formed by coating with organic solvents. By segmenting the light emitting materials into different layers rather than mixing them, the device achieves both low manufacturing cost (through coating method) and high reliability (through proper layer structure)
Solution Approach 2:
The invention uses composite light emitting layers formed by coating organic solvent solutions containing light emitting materials. The combination of organic solvents and light emitting materials creates a coating composition that enables low-cost manufacturing while maintaining device performance through proper material selection and layer structure
3Ease of manufacture
If multiple light emitting materials are incorporated into a single light emitting layer, then color reproduction is improved, but layer complexity and manufacturing difficulty increase
Solution Approach 1:
The invention segments multiple light emitting materials into separate light emitting layers rather than mixing them in a single layer. Each layer contains specific light emitting materials that emit different colors, achieving good color reproduction while simplifying the manufacturing process for each individual layer
Solution Approach 2:
The invention resolves the complexity of mixing multiple light emitting materials by transitioning from a horizontal mixing approach (single layer with multiple materials) to a vertical stacking approach (multiple layers with separate materials). This dimensional change from 2D mixing to 3D stacking simplifies each layer's composition while achieving the same color reproduction goal
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 results in improved luminous efficiency, durability, and color reproducibility, while reducing drive voltage and manufacturing costs, as demonstrated by the use of multiple light emitting layers formed by spraying, which avoids material interference and enhances layer bonding.
Implementation Method 1
at least one of the multiple light emitting layers is formed by coating a liquid containing ingredients to constitute the layer in a state of solution or dispersion in an organic solvent through the use of a spraying method
Implementation Method 2
coating a liquid containing ingredients to constitute the layer in a state of solution or dispersion in an organic solvent
Implementation Method 3
When a voltage is applied to such an organic electroluminescence device, electrons from the negative electrode and holes from the positive electrode are injected into the light emitting layer. These electrons and holes are recombined in the light emitting layer, and luminescence is produced by energy's being emitted in the form of light
Data Source
AI summary
An organic electroluminescence device, having a pair of electrodes, and an organic layer containing multiple light emitting layers provided between a pair of electrodes, wherein at least one of the multiple light emitting layers is formed by coating a liquid containing ingredients to constitute the layer in a state of solution or dispersion in an organic solvent through the use of a spraying method.