Opposite Substrate Spacer Adhesion and Conductivity in OLED Panels
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Solution Overview
Problem
In top-emitting OLED display panels, the thin transparent conductive film used for the cathode has high impedance, leading to a large voltage drop and non-uniform brightness due to poor adhesion of spacers on the conductive metal surface, which affects the product quality.
Innovation Solution
An opposite substrate design with a conductive layer covering the spacer and electrically connected to an auxiliary electrode through a via hole structure, enhancing spacer adhesion by integrating the planarization layer with the spacer and forming them in a single process, thereby improving the product rate and reducing resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a thin transparent conductive film is used for the cathode to increase light transmittance, then light transmittance is improved, but impedance increases leading to large voltage drop and non-uniform brightness
Solution Approach 1:
The patent combines the cathode and auxiliary electrode into a single integrated conductive structure. The auxiliary electrode is formed in the same layer as the cathode, creating a merged conductive system that reduces overall impedance while maintaining high light transmittance. This merged structure allows current to be distributed more uniformly across the display panel, eliminating the voltage drop issues associated with thin transparent conductive films alone.
2Device complexity
If spacers are placed directly on the conductive metal surface, then the structure is simplified, but adhesion is poor causing spacers to fall off
Solution Approach 1:
The patent introduces an intermediary layer between the conductive metal surface and the spacers. This intermediate layer serves as a bonding interface that significantly improves adhesion between the metal substrate and the spacer material. The intermediary layer acts as a chemical or physical bridge, ensuring spacers remain firmly attached during subsequent manufacturing processes and device operation, while the overall structural complexity remains manageable.
3Reliability
If the auxiliary electrode is formed separately from the cathode, then electrical connection is improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges the formation of the auxiliary electrode with the cathode deposition process. Both the cathode and auxiliary electrode are formed in the same layer using a single deposition step, eliminating the need for separate fabrication processes. This merged approach maintains excellent electrical connection between the auxiliary electrode and cathode while significantly reducing manufacturing complexity and production time.
Data Source
AI summary
An opposite substrate, a method for manufacturing the opposite substrate, an organic light-emitting display panel and a display device are provided by the embodiments of the present disclosure. The opposite substrate includes a base substrate, an auxiliary electrode on the base substrate, a planarization layer on a side of the auxiliary electrode facing away from the base substrate, a spacer on a side of the planarization layer facing away from the base substrate, and a conductive layer on a side of the spacer facing away from the base substrate. The conductive layer at least covers a surface of the spacer facing away from the base substrate, and the conductive layer is electrically connected with the auxiliary electrode through a via hole structure passing through the planarization layer.