OLED Cathode Contact and Signal Line Layout for Short Circuit Prevention
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Solution Overview
Problem
In organic light emitting displays, external forces can cause shorts between the cathode electrode and signal lines due to their common electrode configuration, leading to reliability issues.
Innovation Solution
The design includes a cathode electrode with multiple contacts and a global signal line disposed between cathode contacts, using transparent conductive metallic oxides and inorganic/organic insulating materials to prevent short circuits by dispersing local forces and enhancing structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the signal line is disposed on the same layer as the cathode electrode to simplify the structure, then the device complexity is reduced, but the reliability deteriorates due to potential short circuits between the cathode electrode and signal line under external force
Solution Approach 1:
The cathode electrode is divided into multiple segmented electrodes with insulating material disposed between them. This segmentation allows the signal line to be disposed on the same layer as the cathode electrode structure without direct contact, preventing short circuits while maintaining structural simplicity. The insulating material creates electrical isolation between the cathode electrode segments and the signal line.
2Reliability
If the interlayer dielectric layer is made thicker to prevent short circuits, then the reliability improves, but the manufacturing precision requirements increase due to additional process steps
Solution Approach 1:
An insulating material is introduced as an intermediary between the cathode electrode and the signal line. This intermediary layer provides electrical isolation and prevents short circuits without requiring excessive thickness in the interlayer dielectric layer. The insulating material acts as a mediator that enables reliable operation while maintaining manageable manufacturing tolerances.
Data Source
AI summary
Provided is an organic light emitting display device. The device includes an organic electroluminescence element in which a pixel electrode, an intermediate layer including a light emitting layer, and a cathode electrode are successively stacked, a cathode contact including an upper electrode contacting the cathode electrode and a lower electrode disposed on the same layer as the pixel electrode to contact the upper electrode, and a line disposed on the same layer as the lower electrode. At least three cathode contacts are disposed in a direction crossing the line, and the line is disposed between the cathode contacts.