OLED Auxiliary Charge Generation Layer Lifespan
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Solution Overview
Problem
Organic light emitting display (OLED) devices have shorter lifespan compared to other flat panel display devices, necessitating improvements in their longevity and operational stability.
Innovation Solution
The integration of first and second electrodes with light emitting units, N-type and P-type charge generation layers, and auxiliary charge generation layers between these layers to efficiently generate and supply electrons and holes to the emitting layers, enhancing the stability and lifespan of OLEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If conventional charge generation layers are used in OLEDs, then the device structure is simpler, but the lifespan is shorter
Solution Approach 1:
The charge generation layer is segmented into multiple distinct layers (N-type charge generation layer, P-type charge generation layer, and auxiliary charge generation layer) with different functional characteristics. Each layer is positioned at specific locations within the light emitting unit to optimize charge generation and transport, thereby extending device lifespan without creating excessive complexity.
Solution Approach 2:
The auxiliary charge generation layer acts as an intermediary between the N-type and P-type charge generation layers, facilitating improved charge balance and reducing degradation mechanisms. This intermediate layer mediates the interaction between different charge carriers and protects the emitting layer from damage, extending overall device lifespan.
2Duration of action of stationary object
If auxiliary charge generation layers are added to improve lifespan, then the lifespan increases by 35%, but the device complexity increases
Solution Approach 1:
The auxiliary charge generation layer is strategically positioned only in specific regions where it is most needed for charge balance optimization. By applying the additional layer locally rather than uniformly throughout the entire device, the lifespan extension is achieved with minimal increase in overall structural complexity.
3Productivity
If multiple charge generation layers are stacked to improve charge supply, then the current density increases, but the manufacturing complexity increases
Solution Approach 1:
The charge generation layers are designed with predetermined material compositions and thicknesses that are optimized during the design phase. This preliminary optimization allows the layers to self-adjust charge generation during operation, achieving high current density without requiring complex real-time manufacturing control or additional processing 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
This configuration significantly extends the lifespan of OLEDs by up to 35% compared to conventional devices, while maintaining low voltage variation and high current density, ensuring stable operation and improved efficiency.
Implementation Method 1
at least one auxiliary charge generation layer formed between at least any one of the P-type charge generation layer and the N-type charge generation layer and an emitting layer of the light emitting unit disposed on an upper or lower portion of the at least any one thereof and generating electrons and holes supplied to the emitting layer of the light emitting unit
Data Source
AI summary
An organic light emitting display device with improved lifespan is disclosed. The organic light emitting display device includes first and second electrodes facing each other on a substrate, at least two light emitting units formed between the first and second electrodes, an N-type charge generation layer and a P-type charge generation layer sequentially stacked between the light emitting units, and at least one auxiliary charge generation layer formed between at least any one of the P-type charge generation layer and the N-type charge generation layer and an emitting layer of the light emitting unit disposed on an upper or lower portion of the at least any one thereof and generating electrons and holes supplied to the emitting layer of the light emitting unit.