OLED Bank Resin Radical Scavenging for Uniform Display Lifespan
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Solution Overview
Problem
The use of polyimide resin for forming banks in OLED displays leads to display unevenness and a shortened lifespan due to residual photo-radical polymerization initiators promoting light quenching.
Innovation Solution
Incorporating hydrazide, nitroxy radical, or quinone-based compounds as radical scavengers in the light-emitting layers to scavenge remaining radicals, thereby suppressing light emission quenching and extending the display's lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a photo-radical polymerization initiator is used to photopolymerize the methacryl groups in the polyimide resin layer, then the polymerization efficiency is improved, but residual polymerization initiators remain in the unexposed areas and promote light quenching, causing display unevenness and shortened lifespan
Solution Approach 1:
The harmful photo-radical polymerization initiator is extracted and removed from the polyimide resin layer through solvent washing after photopolymerization. This extraction process eliminates the residual initiators that would otherwise remain in unexposed areas and cause light quenching, thereby resolving the contradiction between achieving complete polymerization and preventing harmful residues
Solution Approach 2:
A solvent is introduced as an intermediary substance to facilitate the removal of residual polymerization initiators. The solvent acts as a mediator between the polymerized layer and the harmful residues, enabling selective dissolution and extraction of the initiators without affecting the polymerized structure, thus maintaining both polymerization efficiency and display reliability
2Productivity
If residual photo-radical polymerization initiators remain in unexposed areas, then the polymerization process is complete, but these initiators promote light quenching and reduce display performance
Solution Approach 1:
The residual polymerization initiators, which would normally cause harmful light quenching effects, are converted into a beneficial situation by using them as targets for selective removal. The washing process exploits the solubility difference between the initiators and the polymerized resin, transforming the harmful presence of residues into an opportunity for purification and enhanced display performance
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The introduction of radical scavengers effectively suppresses display unevenness and prolongs the lifespan of OLED devices by neutralizing residual radicals, enhancing efficiency and longevity.
Implementation Method 1
ultraviolet light (i-rays) exposure through a mask is implemented, the methacryl groups of polyimide side chains undergo radical polymerization
Implementation Method 2
the remaining polymerization initiator promotes quenching of light emitted from the element
Data Source
AI summary
A display device includes a display area including a light-emitting element layer including a plurality of light-emitting elements, a TFT layer provided below the light-emitting element layer to drive the plurality of light-emitting elements, and a sealing layer covering the light-emitting element layer, and a frame area surrounding the display area. The light-emitting element layer is provided with a light-emitting layer for each color of red, green, and blue. The light-emitting layer of each color is partitioned by a bank constituted by a resin material, and each light-emitting layer includes a hydrazide compound or a nitroxy radical compound.