OLED Display Panel Groove Contact for IR-Drop Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Top-emitting OLED display devices face issues with inconsistent luminance due to high lateral resistance in the cathode layer, leading to IR-drop defects, especially in large-sized screens, where the center is bright and the edges are dark, caused by the small thickness of the cathode layer.
Innovation Solution
A display panel design featuring a transmissive electrode layer and an auxiliary electrode layer with increased contact area through grooves and support portions, where the auxiliary electrode layer is made of flexible materials like silver nanowires and graphene oxide, ensuring better electrical contact and reduced pressure during bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the cathode layer is made thinner to enable top-emitting OLED structure, then the aperture ratio limitation is reduced and high-resolution display is achieved, but the lateral resistance increases causing IR-drop defects and luminance inconsistency
Solution Approach 1:
The cathode layer is segmented into a transmissive electrode layer (first conductive layer) and an auxiliary electrode layer (second conductive layer) separated by insulating layers. This segmentation allows the transmissive electrode to maintain thin profile for high aperture ratio while the auxiliary electrode provides additional conductive pathways to reduce lateral resistance and eliminate IR-drop defects.
Solution Approach 2:
Multiple insulating layers (first insulating layer, second insulating layer, third insulating layer) are introduced as intermediaries between the transmissive electrode layer and auxiliary electrode layer. These insulating layers enable electrical isolation while maintaining mechanical connection through support portions, allowing the two electrode layers to work cooperatively without direct electrical contact.
2Length of moving object
If the cathode layer thickness is reduced, then the top-emitting structure is achieved, but contact area with auxiliary electrode is insufficient leading to high contact resistance
Solution Approach 1:
The contact between transmissive electrode layer and auxiliary electrode layer is extended from a single-point or single-plane contact to multi-dimensional contact. Support portions penetrate through multiple insulating layers to create vertical contact pathways, while grooves in the first insulating layer provide additional contact surfaces, transforming the contact geometry from 0D/1D to 2D/3D contact.
Solution Approach 2:
The contact interface is segmented into multiple discrete contact points formed by support portions penetrating through insulating layers. This segmentation distributes the contact load across multiple locations and creates numerous parallel conduction pathways, reducing overall contact resistance despite the thin cathode layer thickness.
3Reliability
If support portions are added to increase contact area, then contact resistance is reduced, but bonding pressure between substrates increases
Solution Approach 1:
The third insulating layer is designed with non-uniform thickness, being thinner in regions where support portions are located and thicker in other regions. This local variation in insulating layer quality allows support portions to make closer contact with the transmissive electrode layer, reducing contact resistance, while the thicker regions maintain adequate insulation and distribute bonding pressure.
Solution Approach 2:
The insulating layers are designed as thin film structures that can flexibly accommodate the support portions. The thin third insulating layer at contact regions allows close proximity between electrode layers for low contact resistance, while the overall thin-film architecture distributes mechanical stress during bonding process.
Data Source
AI summary
A display panel includes a base substrate including a first surface; another base substrate including a second surface disposed face the first surface; a first insulating layer disposed above the first surface of the base substrate, a plurality of grooves being disposed in a surface of the first insulating layer away from the base substrate; a first conductive layer disposed at a side of the first insulating layer away from the base substrate, the first conductive layer at least covering bottom faces and side walls of the plurality of grooves; a plurality of support portions disposed above the second surface of the another base substrate; and a second conductive layer disposed at a side of the plurality of support portions away from the another base substrate, the second conductive layer at least covering surfaces of the plurality of support portions facing away from the another base substrate and side faces of the plurality of support portions. Each support portion is embedded into a respective one of the plurality of grooves, and the first conductive layer is in electrical contact with the second conductive layer at the bottom faces and side walls of the plurality of grooves.