Dual Panel OLED Top Emission Contact Layer Design
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Solution Overview
Problem
Current organic electroluminescent display (OLED) devices face limitations in brightness due to bottom emission designs, which are affected by array elements blocking light, and have complex fabrication processes that increase production costs and reduce yield.
Innovation Solution
A dual panel type OLED device is designed as a top emission type with a cathode connected through a contact layer made of molybdenum or indium tin oxide, featuring an overcoat layer and an anode on the emitting layer to improve aperture ratios and prevent shorting, using a simpler production process with N-type thin film transistors and inorganic insulating layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a bottom emission design is used in organic ELD, then the device structure is simple, but brightness is reduced due to light blockage from array elements
Solution Approach 1:
The patent inverts the traditional bottom emission design by implementing a top emission design where the cathode is positioned at the top of the device structure. This allows light to be emitted upward through the anode and emitting layer without being blocked by array elements, thereby significantly improving brightness while maintaining structural simplicity
2Manufacturing precision
If a complex fabrication process is used, then manufacturing precision can be improved, but production cost increases and yield decreases
Solution Approach 1:
The patent employs a simplified fabrication process that utilizes inorganic insulating layers and specific material deposition techniques to achieve the desired device performance without requiring complex multi-step processes, thereby improving production yield while maintaining manufacturing precision
Solution Approach 2:
The fabrication process is segmented into distinct stages: forming N-type thin film transistors with inorganic insulating layers, depositing the cathode through contact layers, and assembling the emitting layers. This segmentation allows each stage to be optimized independently, improving overall production efficiency and yield
3Device complexity
If the cathode is directly connected to the driving element, then the connection is simple, but shorting and separation issues occur
Solution Approach 1:
The patent introduces contact layers made of inorganic insulating materials as intermediary structures between the cathode and the driving element. These contact layers serve as both electrical contacts and protective barriers, preventing direct contact that could cause shorting while also preventing cathode separation, thereby improving connection reliability without significantly increasing structural complexity
Data Source
AI summary
An method of fabricating an organic electroluminescent device includes forming a switching element and a driving element connected to the switching element on a substrate in a pixel region, forming an overcoat layer on the switching element and the driving element, forming a contact layer on the overcoat layer, wherein the contact layer is made of one of molybdenum and indium tin oxide, forming a cathode on the contact layer, the cathode connected to the driving element through the contact layer, forming an emitting layer on the cathode, and forming an anode on the emitting layer.