OLED Display Panel Auxiliary Electrode IR Drop Mitigation
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Solution Overview
Problem
Large-sized OLED display panels face issues with internal resistance (IR) drop due to thin metal or transparent conductive layers, affecting luminance uniformity, which hinders the development of larger displays.
Innovation Solution
Incorporating an auxiliary electrode with lower electrical resistance, electrically connected to the top electrode, and strategically placing it in buffer regions of the isolation layer to mitigate IR drop and enhance luminance uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a thin metal layer or transparent conductive layer is employed as a top electrode to enhance light emitting effect, then light transmittance is improved, but internal resistance increases causing IR drop and non-uniform luminance
Solution Approach 1:
The top electrode is segmented into a main top electrode and multiple auxiliary electrodes distributed across the display panel. The auxiliary electrodes are positioned in buffer regions and have lower electrical resistance, creating multiple parallel current paths that reduce overall resistance and prevent IR drop, while the main top electrode maintains light transmittance functionality.
Solution Approach 2:
Different regions of the display panel are assigned different electrode configurations. The buffer regions contain auxiliary electrodes with lower electrical resistance, while the pixel regions maintain the original top electrode structure optimized for light transmittance. This local differentiation allows simultaneous optimization of both electrical performance and optical performance in different areas.
2Area of stationary object
If the top electrode is enlarged for large-sized OLED display panels, then coverage area is increased, but internal resistance increases causing IR drop
Solution Approach 1:
Instead of using a single large top electrode that would have high resistance, the electrode system is segmented into multiple smaller electrodes (main top electrode and auxiliary electrodes) distributed across the large display panel area. This segmentation reduces the effective resistance by creating multiple parallel current paths, preventing IR drop even in large-sized panels.
Solution Approach 2:
The electrode configuration is extended into the vertical dimension by placing auxiliary electrodes at different positions (in buffer regions) rather than relying solely on a single planar layer. This multi-layer, multi-position arrangement reduces resistance without requiring the top electrode to be excessively enlarged.
3Reliability
If auxiliary electrodes are added to reduce IR drop, then luminance uniformity is improved, but device complexity increases
Solution Approach 1:
The auxiliary electrodes are merged with the existing buffer region structure of the display panel. The buffer regions, which already exist for isolation purposes, are utilized to position the auxiliary electrodes, thereby combining two functions (isolation and electrical compensation) into a single integrated structure without significantly increasing overall device complexity.
Solution Approach 2:
The auxiliary electrodes serve multiple functions: they reduce electrical resistance and prevent IR drop, while also being positioned in buffer regions that provide isolation and structural support. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity.
Data Source
AI summary
A display panel includes a substrate, a plurality of bottom electrodes, an isolation layer, a plurality of light emitting layers, a top electrode, and at least one first auxiliary electrode. The bottom electrodes and the isolation layer are disposed on the substrate. The isolation layer has a plurality of pixel region openings and at least one buffer region. Each of the pixel region openings respectively exposes the corresponding bottom electrode. The buffer region is disposed between two adjacent pixel region openings. The light emitting layers are respectively disposed on the corresponding bottom electrodes. The top electrode covers the light emitting layers, the isolation layer, and the buffer region. The first auxiliary electrode is disposed in the buffer region.