OLED Step Difference Compensation Layer Leakage Current
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Solution Overview
Problem
High-resolution organic light emitting diode (OLED) display devices face issues with leakage current between adjacent pixels, leading to degraded display quality due to narrow pixel spacing, which results in unwanted light emission and color mixture defects.
Innovation Solution
A step difference compensation layer with spike patterns is introduced between adjacent pixels, comprising a base layer and protrusions that extend into the organic light emitting layer, effectively blocking leakage current and maintaining a uniform organic light emitting layer thickness across pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large number of pixels are arranged on a display panel with limited area to achieve high resolution, then pixel per inch (PPI) is improved, but the distance between pixels becomes narrow which causes leakage current to occur
Solution Approach 1:
The pixel definition layer is segmented into multiple regions including pixel emission regions, pixel definition regions, and bridge regions. This segmentation creates distinct functional zones that allow the organic light emitting layer to be selectively positioned, preventing leakage current while maintaining high pixel density.
Solution Approach 2:
The bridge region acts as an intermediary structure connecting adjacent pixel definition regions. It provides a controlled pathway that prevents direct electrical contact between neighboring pixels, thereby blocking leakage current while maintaining structural integrity of the pixel definition layer.
2Measurement precision
If the distance between pixels is reduced to achieve high resolution, then pixel per inch (PPI) is improved, but unwanted pixels may emit light due to leakage current which degrades display quality
Solution Approach 1:
The pixel definition layer is segmented into multiple regions including pixel emission regions, pixel definition regions, and bridge regions. This segmentation creates distinct functional zones that allow the organic light emitting layer to be selectively positioned, preventing leakage current while maintaining high pixel density.
Solution Approach 2:
Different regions of the pixel definition layer are assigned different functions: pixel emission regions allow light emission, pixel definition regions block current, and bridge regions connect structures. This local differentiation ensures that each area performs its specific function optimally, preventing unwanted light emission while maintaining display quality.
3Ease of manufacture
If the organic light emitting layer is formed to cover the entire surface including bridge regions, then manufacturing is simplified, but leakage current can occur through the organic light emitting layer in bridge regions
Solution Approach 1:
The pixel definition layer is segmented into multiple regions including pixel emission regions, pixel definition regions, and bridge regions. This segmentation creates distinct functional zones that allow the organic light emitting layer to be selectively positioned, preventing leakage current while maintaining high pixel density.
Solution Approach 2:
The organic light emitting layer is selectively formed only in pixel emission regions, while the bridge regions remain free of this layer. This local differentiation ensures that the organic light emitting layer does not create leakage pathways in bridge regions, while still simplifying manufacturing by using a blanket deposition process followed by selective removal or non-formation in bridge areas.
Data Source
AI summary
An organic light emitting diode display device can include a substrate; a plurality of pixels disposed on the substrate; a plurality of anodes corresponding to the plurality of pixels, respectively; an organic light emitting layer disposed on the plurality of anodes; a cathode layer disposed on the organic light emitting layer; and a step difference compensation layer partitioning at least two adjacent pixels among the plurality of pixels, in which the step difference compensation layer includes a base layer, and a plurality of spike patterns disposed on the base layer, the plurality of spike patterns including protrusions that extend into at least a portion of the organic light emitting layer in a region between the at least two adjacent pixels.