Auxiliary Power Lines for Uniform OELD Brightness
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Solution Overview
Problem
Conventional organic electroluminescence display (OELD) devices face challenges in manufacturing large-size screens due to non-uniform brightness and image characteristics caused by voltage drops in the power line and cathode, which complicates the manufacturing process and increases power consumption.
Innovation Solution
The implementation of auxiliary power lines, specifically a first and second auxiliary power line, formed on the same layer as the lower electrode, interconnected through insulating layers and via-holes, reduces resistance and prevents voltage drops by electrically connecting to the power line and upper electrode, respectively, thereby improving brightness and image characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional power line structure is used in large-size OELD devices, then device size can be increased, but voltage drops occur causing non-uniform brightness
Solution Approach 1:
The power supply system is segmented into multiple auxiliary power lines (first and second auxiliary power lines) that are distributed across the display device. These auxiliary power lines are formed on the same layer as the lower electrode and interconnected through insulating layers and via-holes, creating a segmented power distribution network that reduces voltage drops across large display areas.
2Ease of manufacture
If conventional power line structure is used, then manufacturing process remains simple, but power consumption increases due to voltage drops
Solution Approach 1:
The auxiliary power lines are merged with the existing lower electrode layer structure, forming both components on the same layer. This integration allows the auxiliary power lines to be manufactured simultaneously with the lower electrode using the same fabrication processes, thereby maintaining manufacturing simplicity while reducing power consumption through improved electrical connectivity.
3Illumination intensity
If auxiliary power lines are added to prevent voltage drops, then brightness uniformity improves, but device structure becomes more complex
Solution Approach 1:
The auxiliary power lines serve multiple functions: they act as both power supply conduits and structural components integrated into the display device architecture. By forming auxiliary power lines on the same layer as the lower electrode and utilizing existing insulating layers and via-holes for interconnection, the structure achieves multi-functionality that reduces brightness non-uniformity without proportionally increasing device complexity.
Data Source
AI summary
An organic electroluminescence device which includes a power line formed on the same layer as source and drain electrodes of a thin film transistor (TFT) and formed on a substrate on which the TFT is formed, a first insulating layer formed on the TFT, a lower electrode that electrically connected to one of the source and drain electrodes of the TFT and disposed on the first insulating layer, a first auxiliary power line and a second auxiliary power line formed on the same layer as the lower electrode in the second insulating layer, a second insulating layer formed on an edge portion of the lower electrode and not formed on the second auxiliary power line, wherein an opening that exposes a portion of the lower electrode is formed, an organic film formed on a substrate; and an upper electrode formed on the substrate.