OLED Pad Electrode Corrosion Prevention via Covering Structure
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Solution Overview
Problem
Top emission type OLED devices face limitations in reducing the resistance of the second electrode and preventing corrosion and metal migration of the pad electrode due to spatial constraints and the need for additional mask processes.
Innovation Solution
The introduction of an auxiliary line connected to the auxiliary electrode below the auxiliary electrode, and a pad cover electrode that covers the upper and side surfaces of the pad connection electrode, reduces the resistance of the second electrode and prevents corrosion and metal migration without adding separate mask processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the second electrode is made thin to reduce material usage and cost, then the resistance of the second electrode increases
Solution Approach 1:
An auxiliary electrode is introduced as an intermediary conductive element between the thin second electrode and the ITO layer. This auxiliary electrode serves as a mediator that provides additional conduction paths, allowing the second electrode to remain thin while maintaining low overall resistance through the combined conductive network.
Solution Approach 2:
The conductive path is extended from a single-layer horizontal arrangement to a multi-dimensional structure by adding the auxiliary electrode in a different spatial layer. This creates a three-dimensional conductive network that reduces resistance without increasing the planar area occupied by the second electrode.
2Reliability
If the auxiliary electrode is enlarged to reduce resistance of the second electrode, then the spatial limitation in the same layer as the first electrode is exceeded
Solution Approach 1:
The auxiliary electrode is positioned in a different spatial layer (below the first electrode layer) rather than attempting to expand horizontally in the same plane. This vertical dimensionality change allows the auxiliary electrode to achieve sufficient conductive area without conflicting with the first electrode's spatial requirements.
Solution Approach 2:
The conductive function is segmented between two separate electrodes: the second electrode provides the primary conduction path, while the auxiliary electrode provides additional conduction paths through a different route. This segmentation allows each electrode to be optimized independently within available space.
3Reliability
If a separate mask process is added to prevent corrosion and metal migration of the pad electrode, then the production efficiency deteriorates
Solution Approach 1:
The pad cover electrode is formed simultaneously with the first and auxiliary electrodes in the same deposition and patterning process. This merging of formation steps eliminates the need for a separate dedicated mask process for the pad cover electrode, thereby preventing corrosion while maintaining production efficiency.
Solution Approach 2:
The pad cover electrode serves multiple functions: it protects the pad electrode from corrosion and metal migration, and it is formed using the same universal deposition and patterning process used for the main electrodes. This multi-functionality approach avoids adding specialized process steps.
Data Source
AI summary
An organic light emitting display device and a method of manufacturing the same are provided that may reduce the resistance of a second electrode and may prevent corrosion and metal migration of a pad electrode without adding a separate mask process, or while reducing the number of mask processes. In the organic light emitting display device, an auxiliary line is connected to a second electrode through an auxiliary electrode, which is provided in the same layer as a first electrode, and a pad cover electrode is configured to cover an upper surface and a side surface of a pad connection electrode so as to prevent the pad connection electrode connected to a pad from being exposed outward.