OLED Pixel Electrode Segmentation for Laser Repair
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Solution Overview
Problem
Organic light emitting displays (OLEDs) suffer from dark spots caused by short circuits between the anode and cathode, which grow in size over time, reducing the device's reliability and lifespan, and conventional laser repair methods often damage surrounding areas, reducing the OLED's lifespan further.
Innovation Solution
The OLED features a pixel electrode divided into cutting unit cells with connected cutting patterns, allowing for localized laser repair by isolating faulty cells from neighboring cells, minimizing damage and maintaining the functionality of other cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional laser repair is applied to remove impurities causing dark spots, then the impurities are removed, but the surrounding areas are damaged providing paths for moisture or oxygen infiltration
Solution Approach 1:
The pixel electrode is divided into multiple isolated regions by insulating layers and contact holes. This segmentation allows the laser beam to be applied locally to specific faulty areas without affecting surrounding regions, as the insulating structures confine the laser impact zone and prevent damage propagation to adjacent functional areas.
Solution Approach 2:
Insulating layers are introduced as intermediary structures between the pixel electrode regions. These insulating layers act as protective barriers that prevent the laser beam from directly damaging the surrounding electrode areas during the repair process, while still allowing the laser to effectively remove impurities in the target zone through the contact holes.
2Reliability
If dark spots are left unrepaired, then the device structure remains intact, but the dark spots grow in size over time reducing reliability
Solution Approach 1:
By segmenting the pixel electrode into isolated regions, the repair process can target individual faulty segments without requiring complex system-level repairs. This simplifies the repair approach compared to conventional methods that would require broader intervention, making the repair process more manageable while effectively preventing dark spot propagation to adjacent segments.
3Reliability
If the pixel electrode is made more robust to prevent short circuits, then reliability improves, but the device becomes less adaptable to laser repair
Solution Approach 1:
The pixel electrode is segmented into multiple regions separated by insulating layers, creating a structure that is both robust against short circuits and adaptable to laser repair. The segmentation provides inherent isolation that prevents short circuits between regions while simultaneously enabling targeted laser repair by confining laser impact to specific segments through the contact holes and insulating barriers.
Solution Approach 2:
Different regions of the pixel electrode are designed with locally optimized properties. The insulating layers and contact holes create zones with different functional characteristics - some areas provide electrical connection while others provide isolation. This local differentiation allows the structure to be both robust (preventing short circuits through isolation) and repairable (allowing localized laser access through contact holes).
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 solution enables effective laser repair of OLEDs by isolating faulty cells, preventing damage to surrounding areas and maintaining the operational integrity of other cells, thus enhancing the reliability and lifespan of the OLED.
Implementation Method 1
attempts were made to fix dark spots through a laser repair process in which a laser beam is applied to impurities such as particles to remove the impurities. The laser beam removes impurities, but it may also damage a region surrounding the impurities.
Data Source
AI summary
An organic light emitting display (OLED) and a method of fabricating the same are provided. The OLED includes: a substrate; a pixel electrode disposed on the substrate and having cells divided into a plurality of cells and cutting patterns connected to the cells; an organic layer having at least an emission layer and disposed on the pixel electrode; and an upper electrode disposed on the organic layer, thereby minimizing the damage of the device and performing laser-repair.