OLED Common Electrode Segmentation for Large Panel Resistance
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Solution Overview
Problem
Organic light emitting display devices face challenges with increased wiring resistance and damage to the common electrode due to encapsulation, particularly when scaling up to larger panels.
Innovation Solution
The design incorporates a second light-transmissive electrode with a thicker third electrode and a capping layer having lower adhesion strength, which reduces wiring resistance and protects the common electrode by allowing for easy patterning without damaging the second electrode during the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the panel size is increased to create large display devices, then the display area is improved, but the wiring resistance of the common electrode increases
Solution Approach 1:
The common electrode is divided into multiple segments (first common electrode and second common electrode) that are electrically connected through connection electrodes. This segmentation allows each segment to have lower individual resistance while maintaining overall electrode functionality across the large panel area.
Solution Approach 2:
The patent introduces a vertical dimension by stacking multiple common electrode layers (first and second common electrodes at different heights) connected by vertical connection electrodes. This three-dimensional arrangement reduces the effective path length for current flow, thereby reducing wiring resistance in the large-area display.
2Device complexity
If the common electrode is used for encapsulation purposes, then the device structure is simplified, but the common electrode may be damaged during manufacturing
Solution Approach 1:
The common electrode system is segmented into multiple functional layers (first common electrode for electrical connection, second common electrode for encapsulation protection). This separation of functions allows the encapsulation layer to protect the electrode without compromising its electrical integrity during manufacturing processes.
Solution Approach 2:
The patent introduces protective layers (insulating layers and encapsulation structures) before the electrode undergoes potential damage during manufacturing. These pre-installed protective structures cushion and protect the common electrode from damage during subsequent manufacturing steps.
3Reliability
If a thick electrode is used to reduce wiring resistance, then the electrical conductivity is improved, but the adhesion strength becomes insufficient for patterning
Solution Approach 1:
The thick electrode is segmented into multiple thinner layers (first common electrode and second common electrode separated by insulating layers). Each layer can be patterned independently with standard techniques, while the combined structure maintains the low resistance benefit of the overall thick electrode configuration.
Solution Approach 2:
The patent transitions from a single-plane thick electrode to a multi-layer three-dimensional structure. This vertical stacking allows each layer to be thinner and more easily patterned, while the cumulative thickness across layers maintains the low resistance property.
Data Source
AI summary
An organic light emitting display device includes a thin film transistor (TFT), a first insulating layer covering the TFT, a first electrode formed on the first insulating layer and electrically connected to the TFT, a second insulating layer that is formed on the first insulating layer and covers the first electrode and has an opening to expose a portion of the first electrode, an organic layer formed on a portion of the second insulating layer and the first electrode, a second electrode formed on the second insulating layer and the organic layer and composed of a first region and a second region, a capping layer formed on a first region of the second electrode and having first edges, and a third electrode formed on a second region of the second electrode and having second edges whose side surfaces contact side surfaces of the first edges of the capping layer.