Segmented Electrode Coating for Roll-to-Roll Organic EL Manufacturing
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Solution Overview
Problem
The existing methods for producing organic electroluminescence elements using a roll-to-roll method face challenges in achieving uniform coating thickness due to step differences between electrodes, leading to luminescence nonuniformity and manufacturing inefficiencies.
Innovation Solution
A method involving the continuous formation of organic functional layers on a belt form flexible substrate with a first electrode, followed by processing the electrode to create discontinuous portions, allowing for stable and uniform coating without the influence of step differences, and subsequent separation of organic EL elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a wet coating method is used to form organic functional layers on patterned first electrodes, then manufacturing cost is reduced and atmospheric pressure processing is enabled, but coating thickness uniformity deteriorates due to step differences between electrodes
Solution Approach 1:
The first electrode is divided into multiple segments with gaps between them, allowing the coating solution to flow uniformly across each segment without being blocked by continuous electrode structures, thereby eliminating step difference effects on coating uniformity
Solution Approach 2:
The electrode pattern is changed from a two-dimensional continuous layer to a segmented structure with controlled gaps, introducing a new dimensional parameter (gap width) that enables uniform coating flow while maintaining electrical functionality
2Productivity
If a roll-to-roll method is used to continuously produce organic EL elements, then manufacturing efficiency is improved, but coating uniformity deteriorates due to step differences causing luminescence nonuniformity
Solution Approach 1:
The continuous first electrode is segmented into discrete sections with gaps, enabling the coating solution to be uniformly deposited across each segment during continuous roll-to-roll processing without experiencing thickness variations from step differences
Solution Approach 2:
The segmented electrode design maintains continuous production capability in roll-to-roll manufacturing while eliminating the harmful effects of step differences, allowing uninterrupted coating process with uniform thickness across all electrode segments
3Reliability
If the first electrode is made continuous to ensure electrical connectivity, then electrical performance is improved, but coating uniformity deteriorates due to step differences at electrode edges
Solution Approach 1:
The electrode is segmented with gaps that are sufficient to allow uniform coating solution flow while maintaining electrical connectivity through the electrode material's conductivity, resolving the conflict between continuous electrical path and uniform coating deposition
Solution Approach 2:
Different regions of the electrode structure serve different functions: the electrode material provides electrical connectivity while the gaps between segments provide coating uniformity, with each local region optimized for its specific purpose
Data Source
AI summary
A method of manufacturing an organic electroluminescence element having on a belt-formed flexible base material, a first electrode, at least one organic functional layer, and a second electrode, includes continuously forming at least one organic functional layer by coating the same on a first electrode which is formed continuously on the flexible base material in the conveying direction thereof, further forming a second electrode on the organic functional layer, so as to make a plurality of organic electroluminescence element structures in the conveying direction, and then cutting the electroluminescence element structures into individual organic electroluminescence elements so as to manufacture organic electroluminescence elements.