Segmented Opposite Electrode for OLED IR Drop Reduction
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Solution Overview
Problem
Large-sized organic light-emitting display apparatuses face issues with increased resistance in the opposite electrode, leading to IR drop and reduced transmittance, which affects the brightness and stability of the display.
Innovation Solution
The organic light-emitting display apparatus incorporates first and second auxiliary electrodes with equal cross-sectional areas, spaced apart, and a connection wiring with higher resistance, where the opposite electrode contacts the ends of these electrodes, reducing resistance gaps and minimizing IR drop by using a half-tone mask to form the connection wiring with a smaller thickness and area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the display apparatus size is increased, then the display area is enlarged, but the resistance of the opposite electrode increases causing IR drop and reduced transmittance
Solution Approach 1:
The opposite electrode is divided into multiple segments (first auxiliary electrode, second auxiliary electrode, and connection wiring) rather than using a single continuous electrode. This segmentation reduces the overall resistance by creating multiple parallel conduction paths, thereby minimizing IR drop while maintaining large display area.
2Area of stationary object
If the opposite electrode area is increased to cover larger display, then the transmittance decreases due to higher resistance and IR drop
Solution Approach 1:
The opposite electrode is segmented into auxiliary electrodes and connection wirings with different resistance characteristics. The auxiliary electrodes have lower resistance for stable electrical contact, while connection wirings with higher resistance are minimized in area, allowing large electrode coverage without compromising brightness.
Solution Approach 2:
Different regions of the electrode structure have different resistance properties. The auxiliary electrodes positioned for direct contact have low resistance, while connection wirings have higher resistance but smaller cross-sectional area, optimizing both electrical stability and light transmittance locally.
3Reliability
If the connection wiring area is reduced to minimize resistance, then the manufacturing precision requirements increase
Solution Approach 1:
The connection wiring is designed with higher resistance and smaller cross-sectional area compared to auxiliary electrodes. By changing the resistance parameter and reducing the area parameter, the wiring achieves minimal resistance contribution while maintaining manufacturability through standard half-tone mask techniques.
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 configuration reduces the resistance of the opposite electrode, minimizing IR drop and maintaining high emission stability and brightness, even in larger display sizes.
Implementation Method 1
an organic light-emitting display apparatus includes: a substrate; a thin film transistor formed on the substrate and including an active layer, a gate electrode, a source electrode, and a drain electrode; a pixel electrode connected to at least one of the source electrode or the drain electrode... including an organic emission layer
Data Source
AI summary
An organic light-emitting display apparatus includes: a substrate; a thin film transistor formed on the substrate; a pixel electrode connected to at least one of the source or drain electrodes; a pixel-defining layer having a first opening exposing at least a portion of the pixel electrode and a second opening adjacent to the first opening; an intermediate layer formed on the pixel electrode, including an organic emission layer, and having a first hole corresponding to the second opening; an opposite electrode formed on the intermediate layer; and first and second auxiliary electrodes formed below the pixel-defining layer, at least portions of the first and second auxiliary electrodes are exposed through the second opening, where ends of the first and second auxiliary electrodes are spaced apart from each other, and where the opposite electrode contacts the ends of the and second first auxiliary electrodes which are exposed through the first hole.