OLED Electrode Segmentation for Short Circuit Prevention
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Solution Overview
Problem
Organic light emitting devices (OLEDs) are prone to short defects due to factors like pinholes, cracks, and electrode misalignment, leading to reduced light emission and operational failures, which existing manufacturing methods struggle to completely eliminate without increasing costs or compromising device reliability.
Innovation Solution
The OLED design incorporates a first electrode with multiple conductive units and connections, where each conductive unit has two or more connections with a longer current flow direction than width, and a current carrying unit or auxiliary electrode that electrically connects these, providing a higher resistance path to prevent short circuits and maintain device functionality even with defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of organic layer is increased to decrease short defects, then the distance between electrodes increases reducing short defects, but manufacturing costs increase and short defects may not be completely removed
Solution Approach 1:
The first electrode is segmented into multiple independent conductive units (101-1 to 101-n) that are spatially separated. Each conductive unit can independently emit light, and if one unit experiences a short defect, the other units continue to function. This segmentation transforms a single-point-failure system into a multi-point-redundancy system, resolving the contradiction by maintaining reliability without requiring increased organic layer thickness.
Solution Approach 2:
Different regions of the electrode structure are assigned different functions: conductive units (101-1 to 101-n) are designed with specific resistance values (100-1000 ohms) to limit current in case of shorts, while conductive connections (201, 202) provide low-resistance pathways for normal operation. This local differentiation of electrical properties allows the system to simultaneously optimize for normal performance and fault tolerance without increasing overall thickness.
2Reliability
If conductive connections with higher resistance are used to prevent short circuits, then leakage current is reduced, but voltage drop increases and device efficiency decreases
Solution Approach 1:
The electrode system is divided into conductive units with higher resistance (100-1000 ohms) for short-circuit protection and conductive connections with lower resistance for efficient current transport. This segmentation allows different parts of the system to have optimized resistance values for their specific functions, resolving the contradiction between safety and efficiency.
Solution Approach 2:
The resistance values of different electrode components are precisely controlled within specific ranges: conductive units are designed with 100-1000 ohms to limit leakage current, while conductive connections are designed with lower resistance to minimize voltage drop. This parameter optimization resolves the contradiction by ensuring that high resistance only appears where needed for protection, not in current-carrying paths.
3Reliability
If multiple conductive connections are provided for each conductive unit, then redundancy is increased improving reliability, but device complexity increases
Solution Approach 1:
The electrode system is segmented into multiple independent conductive units (101-1 to 101-n), each with multiple conductive connections. This segmentation provides inherent redundancy: if one conductive unit or connection fails, others can compensate. The modular nature of this segmentation actually simplifies the overall system design and manufacturing compared to a monolithic electrode structure.
Solution Approach 2:
The conductive connections serve multiple functions: they provide electrical connection between conductive units and current carrying units, they act as current limiters in case of shorts, and they maintain structural integrity. This multi-functionality reduces the need for separate protective components, thereby reducing overall device complexity while maintaining high reliability.
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 design allows OLEDs to operate normally even with short defects, stabilizes current flow, and prevents excessive leakage current, ensuring reliable operation without increasing the number of defects or manufacturing costs.
Implementation Method 1
the conductive connection includes a region in which a length of a current flowing direction is longer than a width of a direction vertical thereto. The resistance of the conductive connections satisfies the conditions laid down in claim 1
Implementation Method 2
An organic light emission phenomenon refers to a phenomenon converting electrical energy to light energy using an organic material. When a proper organic material layer is placed between an anode and a cathode and a voltage is applied between the two electrodes, holes and electrons are injected to the organic material layer from the anode and the cathode, respectively. These injected holes and electrons meet to form excitons, and light emits when these excitons fall back to the ground state.
Data Source
Figure 1
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AI summary
The present specification relates to an organic light emitting device.