Segmented Common Layer for OLED Leakage Current Isolation
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Solution Overview
Problem
Organic light-emitting display apparatuses face issues with non-light-emitting pixels emitting light due to leakage current between adjacent organic light-emitting diodes, which reduces display quality.
Innovation Solution
A display apparatus design featuring a substrate with pixel electrodes and emission layers of different wavelength bands, where the common layers and charge generation layers are patterned to prevent leakage current, including disconnected pattern units for each pixel to isolate driving current and prevent unwanted light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If common layers are made continuous to improve manufacturing simplicity, then manufacturing ease is improved, but leakage current occurs between adjacent organic light-emitting diodes causing display quality degradation
Solution Approach 1:
The continuous common layer is divided into multiple disconnected pattern units, each corresponding to a specific pixel electrode. This segmentation prevents leakage current from spreading between adjacent organic light-emitting diodes while maintaining the common layer's essential functions within each pixel region.
Solution Approach 2:
The common layer is designed with different patterns in different regions - disconnected pattern units in regions where pixel electrodes are located to prevent leakage current, while maintaining appropriate connectivity in other regions. This local differentiation resolves the contradiction between manufacturing simplicity and display quality.
2Manufacturing precision
If pixel electrodes are placed closer together to increase resolution, then display resolution is improved, but leakage current between adjacent diodes increases reducing display quality
Solution Approach 1:
By segmenting the common layer into disconnected pattern units that align with individual pixel electrodes, the invention creates electrical isolation between adjacent diodes. This allows pixel electrodes to be placed closer together for higher resolution without suffering from leakage current interference between neighboring pixels.
3Productivity
If continuous common layers are used to simplify manufacturing, then manufacturing efficiency is improved, but leakage current causes unwanted light emission from non-light-emitting pixels
Solution Approach 1:
The common layer is segmented into disconnected pattern units that correspond to individual pixel electrodes. This segmentation can be achieved through standard photolithography processes, maintaining manufacturing efficiency while preventing the harmful effect of leakage current that causes unwanted light emission from non-active pixels.
Solution Approach 2:
The harmful continuous connectivity of the common layer is extracted and removed in the regions between pixel electrodes. By taking out the continuous path that allows leakage current, the invention eliminates unwanted light emission while preserving the common layer's functionality within each pixel region.
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 solution effectively prevents leakage current between adjacent organic light-emitting diodes, enhancing display quality by ensuring accurate color emission and improving the resolution, lifetime, and efficiency of the organic light-emitting diodes.
Implementation Method 1
a first lower emission layer, a second lower emission layer, and a third lower emission layer respectively corresponding to the first through third pixel electrodes and configured to emit light of different wavelength bands
Data Source
AI summary
A display apparatus, a mask assembly for manufacturing the display apparatus, and an apparatus for manufacturing the display apparatus. The display apparatus includes a substrate, a first pixel electrode, a second pixel electrode, and a third pixel electrode located on the substrate and adjacent to one another, a first lower emission layer, a second lower emission layer, and a third lower emission layer respectively corresponding to the first through third pixel electrodes and configured to emit light of different wavelength bands, a counter electrode located on the first through third lower emission layers, and a first common layer located between the first through third pixel electrodes and the first through third lower emission layers. The first common layer includes a 1-1st pattern unit, a 1-2nd pattern unit, and a 1-3rd pattern unit respectively corresponding to the first through third pixel electrodes and disconnected from one another.