OLED Cathode IR-Drop Reduction via Laser-Ablated Nucleation Inhibiting Layer
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Solution Overview
Problem
Large-sized OLED display panels experience significant resistance voltage drops due to high surface resistance of common cathodes, leading to poor brightness uniformity across different locations.
Innovation Solution
A manufacturing method involving a substrate with a common electrode and nucleation inhibiting layer, where the nucleation inhibiting layer is laser-ablated in non-pixel regions to form a patterned layer, allowing for a conductive layer with greater thickness to be formed, thereby reducing resistance voltage drops and improving brightness uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a common cathode with high transmittance metal or transparent oxide is used in large-size OLED display panels, then the display can achieve full color display with large areas, but the common cathode surface resistance is high causing serious power voltage drop (IR-drop) and poor brightness uniformity
Solution Approach 1:
The common cathode is segmented into two functional layers: a first conductive layer (metal layer) for providing low resistance and reducing IR-drop, and a second conductive layer (transparent oxide layer) for providing high transmittance. This segmentation allows each layer to specialize in one function, resolving the contradiction between low resistance and high transmittance requirements.
Solution Approach 2:
The common cathode uses a composite structure combining metal material (such as Al, Mo, or Cu) and transparent oxide material (such as ITO, IZO, or IGZO). The metal layer provides excellent electrical conductivity while the transparent oxide layer provides high optical transmittance, together achieving both low resistance and high transmittance that neither material could achieve alone.
2Reliability
If the conductive layer thickness is increased to reduce surface resistance and voltage drop, then the electrical conductivity improves, but the manufacturing precision and grid continuity of the conductive layer formation becomes more difficult to control
Solution Approach 1:
The conductive layer is segmented into two separate layers with different thicknesses and functions. The first conductive layer (metal) has greater thickness for low resistance, while the second conductive layer (transparent oxide) has smaller thickness for transmittance. This segmentation allows each layer to be optimized independently, with the metal layer providing the primary conductivity without requiring excessive thickness.
Solution Approach 2:
The patent changes the material parameters by using metal material for the first conductive layer and transparent oxide material for the second conductive layer. This parameter change allows achieving high conductivity with controlled thickness, as metal materials provide superior electrical conductivity per unit thickness compared to transparent oxides, enabling precise control over layer thickness while maintaining low resistance.
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
The method effectively reduces resistance voltage drops and enhances brightness uniformity across large-sized OLED display panels by creating a patterned nucleation inhibiting layer using laser ablation, ensuring good grid continuity and high accuracy in the conductive layer formation.
Implementation Method 1
using a laser to ablate and remove the nucleation inhibiting layer in the non-pixel region to form a patterned nucleation inhibiting layer
Data Source
AI summary
The present invention provides a display panel and a manufacturing method thereof. By using a laser ablation to form a patterned nucleation inhibiting layer with good grid continuity and high accuracy, and using a nucleation inhibiting layer to inhibit a conductive layer from being formed on a surface of the nucleation inhibiting layer and to form the conductive layer with good continuity on a common electrode in a non-pixel region, thereby improving a resistance voltage drop of a cathode formed by the common electrode and the conductive layer, and improving uniformity of brightness of a display on the display panel.