OLED Emissive-Transport Interface Layout for Longer Lifespan
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Solution Overview
Problem
Conventional organic light emitting devices have unsatisfactory lifespan properties due to impurities infiltrating the interfaces between emissive and electron transport layers during the manufacturing process.
Innovation Solution
An organic light emitting device with a multilayer structure featuring emissive layers (red, green, blue) and electron transport layers, where the electron transport layers are formed in the same chamber as the respective emissive layers to prevent impurity infiltration, and a common electron transport layer is used across all sub-pixels, ensuring identical thickness ratios and patterns for improved interface characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If electron transport layers are formed in separate chambers from emissive layers, then manufacturing flexibility is improved, but impurity infiltration occurs at interfaces reducing device lifespan
Solution Approach 1:
The patent merges the formation of electron transport layers and emissive layers into the same deposition chamber, eliminating the interface between layers that would otherwise be exposed to chamber impurities. This combining of operations prevents impurity infiltration while maintaining manufacturing flexibility through controlled sequential deposition.
Solution Approach 2:
The patent introduces an intermediary approach where the electron transport layer and emissive layer are deposited in the same chamber environment, using the chamber itself as a controlled intermediary space that prevents external impurity contamination at the layer interface during the transition between different material depositions.
2Reliability
If multiple separate electron transport layers are formed for each sub-pixel, then interface characteristics are improved, but device structure complexity increases
Solution Approach 1:
The patent segments the electron transport function into multiple layers with different roles: the first electron transport layer forms a patterned interface with each emissive layer to optimize local electron transport and prevent impurity infiltration, while the second electron transport layer provides a common uniform layer across all sub-pixels for overall electron transport. This segmentation resolves the contradiction by assigning different functions to different layers.
Solution Approach 2:
The patent applies local quality by making the first electron transport layer pattern-specific to each sub-pixel (red, green, blue) to optimize local interface characteristics, while the second electron transport layer provides uniform quality across all sub-pixels. This allows tailored interface optimization without requiring complete customization of the entire electron transport structure.
3Device complexity
If conventional stacked structure is used, then device simplicity is maintained, but lifespan properties remain unsatisfactory
Solution Approach 1:
The patent applies preliminary action by forming the electron transport layers in the same deposition chamber as the emissive layers before device assembly is complete. This preliminary formation of the interface in a controlled environment prevents subsequent impurity infiltration that would occur with conventional separate-chamber formation, thereby extending device lifespan without significantly increasing structural complexity.
Data Source
AI summary
An organic light emitting device that has improved lifespan properties by improving the characteristics of an interface between at least one of a red emissive layer, a green emissive layer or a blue emissive layer, and an electron transport layer, and a method of manufacturing the organic light emitting device.