Dummy Sub-Pixels for OLED Edge Uniformity
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Solution Overview
Problem
Conventional OLED displays experience display unevenness at the edges due to poor bonding between the mask and substrate, leading to cyan or pink edges and a high failure rate, which affects display quality and production yield.
Innovation Solution
Incorporating dummy sub-pixels made of the same material as the regular sub-pixels in the non-display region, with these dummy sub-pixels overlapping the electrode contact region, allowing the evaporation edge to be externally expanded to the periphery of the display region, thereby increasing the shadow region and improving the yield of the organic layer near the edge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the mask is bonded to the substrate for evaporating light-emitting material, then the light-emitting material layer can be deposited in regular sub-pixels, but poor bonding at the edge causes display unevenness and color cast
Solution Approach 1:
The patent applies preliminary action by forming dummy sub-pixels in advance at the edge of the display region, before the actual light-emitting material evaporation process. These dummy sub-pixels serve as a preparatory structure that compensates for the mask bonding issue at the edge, ensuring uniform material deposition across the entire display region including the edges.
Solution Approach 2:
The patent converts the harmful effect of mask bonding failure at the edge into a beneficial solution by intentionally designing dummy sub-pixels in the non-display region. The poor bonding that causes material deficiency in regular edge sub-pixels is compensated by the presence of dummy sub-pixels that receive adequate material deposition, thereby balancing the overall display uniformity.
2Manufacturing precision
If dummy sub-pixels are added in the non-display region overlapping the electrode contact region, then display uniformity at edges is improved, but the device structure becomes more complex
Solution Approach 1:
The dummy sub-pixels serve multiple functions: they act as compensation structures for mask bonding issues, serve as material deposition zones during evaporation, and can potentially function as additional display elements if needed. This multi-functionality justifies the added structural complexity by providing multiple benefits from a single design element.
Solution Approach 2:
The patent addresses the edge uniformity problem by moving into another dimension - the non-display region beyond the traditional display boundaries. By placing dummy sub-pixels in this extended dimension, particularly in the electrode contact region, the solution resolves the edge effect without interfering with the core display functionality.
3Productivity
If the evaporation edge is expanded to the periphery of the display region, then the shadow region increases and yield improves, but the area occupied by dummy sub-pixels increases
Solution Approach 1:
The patent applies local quality by concentrating the dummy sub-pixels specifically in the non-display region and electrode contact area, rather than uniformly distributing them across the entire substrate. This localized approach provides the necessary compensation for edge effects while minimizing the total area occupied by dummy structures, thus preserving production yield without excessive area consumption.
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 reduces display unevenness caused by color cast due to poor bonding, enhancing the display quality and production line yield by ensuring a more uniform light-emitting material layer at the edges.
Implementation Method 1
the pixel openings are configured to correspond to a regular sub-pixel region to evaporate a light-emitting material layer of the regular sub-pixels in an evaporation process
Implementation Method 2
to evaporate a light-emitting material layer of the regular sub-pixels in an evaporation process
Data Source
AI summary
A display panel, a display apparatus and a mask are provided. The display panel includes a substrate, first dummy sub-pixels and regular sub-pixels. The display panel has a display region and a non-display region, and the non-display region has an electrode contact region. The display panel includes a substrate, and first dummy sub-pixels and regular sub-pixels located at a same side of the substrate. At least a part of the first dummy sub-pixels overlaps with the electrode contact region in a direction perpendicular to the substrate. The regular sub-pixels are located in the display region and includes first-color sub-pixels, and the first-color sub-pixels each include a first light-emitting material layer. The first dummy sub-pixels have a same material as the first light-emitting material layer.