OLED Display Sub-Pixel Stacked Emissive Layers Lifetime
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Solution Overview
Problem
Conventional organic light emitting devices (OLEDs) have limited lifetimes due to the shorter average lifetime of blue sub-pixels, which restricts the overall device performance and requires increased power consumption, necessitating a solution to enhance device longevity and efficiency.
Innovation Solution
Implementing a stacked sub-pixel configuration with varying numbers of emissive layers for different colors, where blue sub-pixels use multiple emissive layers and red and green sub-pixels use single or fewer emissive layers, allowing for improved device lifetime and reduced power consumption without significant cost or manufacturing complexity increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If blue sub-pixels use single emissive layer configuration, then device manufacturing is simpler, but device lifetime is limited
Solution Approach 1:
The invention divides the blue sub-pixel into multiple separate emissive layers (first blue emissive layer and second blue emissive layer) instead of using a single layer. Each layer can be independently optimized and controlled, allowing the device to achieve extended lifetime by distributing the operational stress across multiple layers while maintaining manageable manufacturing complexity through systematic layer integration.
Solution Approach 2:
The invention transitions from a single-dimensional (single layer) blue emissive structure to a multi-dimensional (stacked layers) structure. By adding the vertical dimension of multiple emissive layers, the device achieves enhanced lifetime performance without proportionally increasing manufacturing complexity, as the additional layers can be integrated into the existing device architecture.
2Duration of action of stationary object
If blue sub-pixels use multiple emissive layers, then device lifetime increases, but power consumption increases
Solution Approach 1:
The invention applies different operational characteristics to different blue emissive layers. The first blue emissive layer and second blue emissive layer can be optimized with different materials, thicknesses, and operating conditions tailored to their specific roles. This local optimization allows the system to extend lifetime while managing power consumption by directing higher current density to layers better suited for high-current operation.
Solution Approach 2:
The invention changes key parameters of the emissive layers including material composition, layer thickness, and operating current density. By optimizing these parameters for each layer, the system achieves extended lifetime through distributed operational stress while reducing overall power consumption compared to a single high-stress layer configuration.
3Duration of action of stationary object
If stacked sub-pixel configuration is implemented, then device lifetime increases, but manufacturing complexity increases
Solution Approach 1:
The invention merges multiple blue emissive layers into a unified stacked configuration that functions as an integrated system. The layers share common structural elements and can be manufactured using similar processes, allowing the complex multi-layer structure to be produced with only moderate increases in manufacturing complexity compared to single-layer devices.
Solution Approach 2:
The stacked emissive layer configuration serves multiple functions simultaneously: it extends device lifetime through distributed stress, enables flexible current distribution for power management, and maintains compatibility with existing manufacturing processes. This multi-functionality justifies the moderate increase in manufacturing complexity by delivering multiple performance benefits from a single architectural change.
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 can increase the device lifetime by up to a factor of three and reduce power consumption by approximately 15%, while maintaining minimal increases in Total Average Cycle Time and capital costs, thereby enhancing display performance and efficiency.
Implementation Method 1
OLEDs make use of thin organic films that emit light when voltage is applied across the device
Implementation Method 2
One application for phosphorescent emissive molecules is a full color display
Data Source
AI summary
Light emitting devices including sub-pixels having different numbers of emissive layers are provided. At least one sub-pixel of a first color may include a single emissive layer, and at least one sub-pixel of a second color may include multiple emissive layers disposed in a vertical stack. Light emitting devices in which different voltages are applied to each sub-pixel or group of sub-pixels are also provided. In some configurations, the voltage to be applied to a sub-pixel may be selected based upon the number of emissive layers in the sub-pixel.