Common Hole Injection Layer Leakage Current Control
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Solution Overview
Problem
In organic EL display units, a common hole injection layer between pixels leads to leakage current due to its low resistivity, causing unintended light emission and image quality degradation through color mixture.
Innovation Solution
The implementation of electrically-conductive wiring layers between pixels, which are electrically connected to a common hole injection layer, effectively draws leakage current before it reaches adjacent pixels, suppressing unwanted light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a common hole injection layer is provided between pixels, then productivity is improved and cost is reduced, but leakage current occurs between adjacent pixels causing color mixture and image quality degradation
Solution Approach 1:
An electrically-conductive wiring layer is introduced as an intermediary between adjacent pixels. This wiring layer is electrically connected to the common hole injection layer and serves to intercept and conduct leakage current away from adjacent pixels, thereby preventing color mixture while maintaining the productivity benefits of a common hole injection layer structure
Solution Approach 2:
The low resistivity of the hole injection layer, which initially causes harmful leakage current, is converted into a beneficial feature. By electrically connecting the hole injection layer to conductive wiring layers, the leakage current is channeled through these wiring layers to ground or other safe paths, transforming the harmful current flow into a controlled electrical path that protects pixel isolation
2Device complexity
If a common hole injection layer is provided between pixels, then manufacturing complexity is reduced, but image quality deteriorates due to color mixture from leakage current
Solution Approach 1:
The conductive wiring layer acts as a mediator that preserves the simplicity of the common hole injection layer structure while adding minimal complexity. These wiring layers are formed using standard thin-film deposition techniques and are integrated into the existing pixel structure, adding only one or two additional layers that significantly reduce color mixture without substantially increasing manufacturing complexity
Solution Approach 2:
The common hole injection layer is functionally segmented by the conductive wiring layers that run between pixels. While the hole injection layer remains physically continuous for manufacturing simplicity, the conductive wiring layers create electrical segmentation that prevents leakage current from affecting adjacent pixels, thereby maintaining image quality
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
This solution significantly reduces leakage current between pixels, thereby preventing color mixture and improving image quality by ensuring only the intended pixel emits light.
Implementation Method 1
The holes and the electrons are recombined to each other and generate energy. The generated energy is taken out as light.
Data Source
AI summary
A display panel includes: a plurality of pixels arranged in a display region, the pixels each including an organic EL element; and a plurality of electrically-conductive wiring layers each arranged between the pixels. The organic EL element includes a plurality of layers including a hole injection layer and a light emitting layer, the light emitting layer emitting light by recombination of an electron and a hole. The hole injection layer of the plurality of layers is common to the pixels in the display region and is electrically connected to the electrically-conductive wiring layers.