OLED Edge Electric Field Reduction via Passivation Groove
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Solution Overview
Problem
Conventional organic light emitting display devices (OLEDs) face degradation due to excessive electric field influence at the edge of the first electrode, leading to reduced lifetime, as electric charges concentrate and apply excessive voltage to the organic layer.
Innovation Solution
Increasing the gap between the edge of the first electrode and the second electrode by forming a groove in the passivation layer, thereby reducing the electric field and minimizing its influence on the organic layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the gap between the first electrode and the second electrode is reduced to minimize device thickness, then the device thickness is reduced, but the electric field concentration at the electrode edge increases causing organic layer degradation
Solution Approach 1:
The gap region between the first and second electrodes is segmented into two parts: a first gap region closer to the first electrode and a second gap region closer to the second electrode. The second gap region has a larger width than the first gap region, creating a gradient structure that distributes the electric field more evenly and reduces concentration at the electrode edges while maintaining overall device thickness.
Solution Approach 2:
Different regions of the gap have different widths to address local electric field concentration issues. The gap width varies locally - narrower near the first electrode and wider near the second electrode - to optimize both thickness and reliability in different spatial locations rather than using a uniform gap width throughout.
2Ease of manufacture
If a uniform gap structure is used between electrodes, then the manufacturing process is simplified, but electric field concentration at electrode edges causes organic layer degradation
Solution Approach 1:
The gap structure is divided into multiple segments with different widths (first gap region and second gap region) to reduce electric field concentration. This segmented approach maintains manufacturing feasibility while effectively addressing the harmful electric field concentration through a controlled gradient structure.
3Reliability
If the electrode gap is increased to reduce electric field concentration, then organic layer degradation is reduced, but the device thickness and volume increase
Solution Approach 1:
The gap width is optimized locally in different regions rather than uniformly increasing the entire gap. The second gap region near the second electrode is widened to reduce electric field concentration and protect the organic layer, while the first gap region near the first electrode maintains a smaller width to minimize overall device thickness.
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 reduces the degradation of the organic layer, thereby increasing the lifetime of the OLED by minimizing the electric field impact on the edge region of the unit pixel.
Implementation Method 1
degradation of unit pixel edges caused by an electric field between an anode and a cathode by increasing a gap between the anode and the cathode
Data Source
AI summary
An organic light emitting display device (OLED) and a method of fabricating the same, in which electric field influence between first and second electrodes is reduced in an edge region of a unit pixel. The OLED includes a substrate, and a thin film transistor (TFT) located on the substrate. A passivation layer is located on the TFT over substantially an entire surface of the substrate, and has a via hole for exposing source or drain electrode, and a groove. A first electrode on the passivation layer is in electrical contact with the exposed source or drain electrode through the via hole, and has an edge located in the groove. A pixel defining layer is located on the first electrode and has an opening for exposing a predetermined portion of the first electrode. An organic layer is in contact with the predetermined portion, and a second electrode is formed on the organic layer.