OLED Sub-Pixel Spacer Structure to Block Lateral Current Leakage
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Solution Overview
Problem
Conventional organic light-emitting display devices suffer from lateral current leakage, which causes adjacent sub-pixels to be turned on, leading to deteriorated color purity and difficulty in displaying pure blue gradation.
Innovation Solution
The organic light-emitting display device incorporates a substrate with a plurality of pixels, each comprising a first sub-pixel, a second sub-pixel, and a third sub-pixel. A first spacer with a negatively tapered shape is provided on the bank between the first and second sub-pixels, preventing lateral current leakage by disconnecting the organic stack between sub-pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If other organic layers are continuously formed in common in the respective sub-pixels without the shadow mask, then manufacturing complexity is reduced, but lateral current leakage occurs
Solution Approach 1:
The patent divides the continuous organic layer into separate segments by introducing a spacer structure between adjacent sub-pixels. The spacer physically separates the organic layers, preventing lateral current leakage while maintaining the simplified manufacturing process of continuous deposition without shadow masks.
Solution Approach 2:
The spacer acts as an intermediary structure between adjacent sub-pixels. It is positioned between the organic layers of neighboring sub-pixels, blocking the lateral flow of current through the organic material while allowing the organic layers to be continuously formed over the entire substrate.
2Object-generated harmful factors
If the spacer is positioned to fully cover the emission portion, then lateral current leakage is prevented, but the emission area is reduced
Solution Approach 1:
The spacer is positioned locally at the boundaries between sub-pixels rather than uniformly across the entire emission area. This localized placement prevents lateral current leakage at the critical interfaces between sub-pixels while preserving the emission area of each individual sub-pixel.
Solution Approach 2:
The spacer extends partially over the emission portion rather than fully covering it. This partial coverage is sufficient to block lateral current leakage at the sub-pixel boundaries while minimizing the impact on the emission area, achieving the necessary protection without excessive material coverage.
Data Source
AI summary
Disclosed is an organic light-emitting display device, which prevents lateral current leakage by providing a structure on a bank so as to cut off an organic material, which is formed in a subsequent process, around the structure.