OLED Second Electrode Laser Connection for Low Resistance
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Solution Overview
Problem
The thin upper electrode in organic light emitting displays (OLEDs) increases electrical resistance, deteriorating display quality due to reduced electrical conductivity, which is a challenge in maximizing light emission while maintaining optimal thickness for top emission type OLEDs.
Innovation Solution
A method involving the formation of a first and second electrode on substrates with a bank pattern, where a laser beam is used to electrically connect a sub-electrode to the second electrode, reducing its resistance and allowing for a thin, transparent conductive second electrode to enhance light transmission while preventing foreign substance diffusion with a filling layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the upper electrode thickness is reduced to maximize light transmission, then light emission is improved, but electrical resistance increases and electrical conductivity deteriorates
Solution Approach 1:
The electrode system is divided into two parts: a first electrode with optimized thickness for light transmission and a second electrode with sufficient thickness for electrical conductivity. The first electrode (transparent conductive layer) has thickness of 50-200 nm for maximum light emission, while the second electrode (metal layer) has thickness of 50-200 nm for low electrical resistance. This segmentation allows each electrode to be optimized for its specific function without compromise.
Solution Approach 2:
The upper electrode structure uses composite materials combining transparent conductive materials (such as ITO, IZO, or ZnO) with metal materials (such as Al, Ag, or Mo). The transparent conductive material layer provides optical transparency and basic conductivity, while the metal layer provides low electrical resistance. This composite structure achieves both high light transmission and good electrical conductivity simultaneously.
2Illumination intensity
If the upper electrode thickness is reduced to improve display quality, then light transmission is maximized, but manufacturing precision becomes more difficult to control
Solution Approach 1:
The electrode function is segmented between two separate layers, allowing the transparent conductive layer to be optimized for light transmission with thin thickness (50-200 nm) without requiring extremely precise thickness control. The manufacturing tolerance can be distributed across both layers, making the overall structure more robust to manufacturing variations.
Solution Approach 2:
The patent specifies optimal thickness ranges (50-200 nm for transparent conductive layer, 50-200 nm for metal layer) rather than single fixed values, providing manufacturing flexibility. This parameter range approach allows manufacturers to achieve acceptable performance within reasonable tolerance ranges, improving manufacturability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves electrical conductivity and display quality by reducing the second electrode's resistance and maintaining a thin thickness for maximum light emission, while preventing foreign substance diffusion between substrates.
Implementation Method 1
a laser beam is irradiated to electrically connect the first sub-electrode and the second electrode
Data Source
AI summary
In a method of manufacturing an organic light emitting display, an organic light emitting layer and a second electrode are sequentially formed on a first sub-electrode, and a laser beam is irradiated onto the organic light emitting layer to partially remove the organic light emitting layer, so that the first sub-electrode is electrically connected to the second electrode. Thus, even though the second electrode is formed to have a small thickness in order to maximize an amount of light that is generated by the organic light emitting layer and exits to an exterior through the second electrode, the second electrode is electrically connected to the first sub-electrode, thereby reducing an electrical resistance of the second electrode.