OLED Panel Auxiliary Electrode Layout for Cathode Impedance Reduction
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Solution Overview
Problem
Large-size OLED display panels face issues with brightness unevenness due to high impedance and current drop in the metal cathode, leading to poor display quality.
Innovation Solution
Incorporating a first auxiliary electrode with a undercut opening between the substrate and the light emitting layer, which reduces the impedance of the second electrode layer by acting as a parallel resistance, and eliminates the need for additional process steps to create undercut openings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the metal cathode is thinned to increase transmission rate, then the transmission rate is improved, but the impedance increases causing serious current drop and brightness unevenness
Solution Approach 1:
The invention divides the cathode structure into multiple segments: the original thin metal cathode layer and additional cathode material deposited in the undercut opening. This segmentation allows the cathode to maintain both high transmission rate (thin main layer) and low impedance (supplementary material in undercut), resolving the contradiction between transmission and electrical performance.
Solution Approach 2:
The invention transitions from a planar cathode structure to a three-dimensional structure by creating undercut openings and depositing cathode material on the sidewalls. This dimensional change adds vertical conductive pathways alongside the horizontal current flow, reducing impedance without compromising the transmission rate of the main cathode layer.
2Reliability
If additional undercut opening steps are added to reduce impedance, then the impedance is improved, but the manufacturing process complexity increases
Solution Approach 1:
The invention merges the undercut opening formation step with the existing cathode material deposition process. The same deposition equipment and parameters used for forming the main cathode layer are utilized to deposit additional material in the undercut openings, eliminating the need for separate processing steps and reducing manufacturing complexity.
Solution Approach 2:
The undercut opening structure itself serves dual purposes: it provides the geometric feature needed for additional cathode material deposition and simultaneously acts as the deposition template. The sidewalls of the undercut automatically guide and define the shape of the supplementary cathode material, eliminating the need for additional patterning or masking steps.
Data Source
AI summary
A display panel, a manufacturing method thereof, and a display device are provided. The display panel includes a substrate and a light emitting device layer disposed on the substrate, and the light emitting device layer includes a first electrode layer, a light emitting layer, and a second electrode layer disposed on the substrate in a stacked manner. The present application provides a first auxiliary electrode disposed between the substrate and the light emitting layer, where, the first auxiliary electrode includes a first undercut opening penetrating through the first auxiliary electrode, where a side edge of the first auxiliary electrode is exposed within the opening, the light emitting layer is disconnected at first undercut opening, the second electrode layer is disposed continuously at the first undercut opening, and at least a portion of the second electrode layer is in contact with the edge of the first auxiliary electrode.