Pixel-Defining Layer Support Structure to Limit OLED Pixel Leakage
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Solution Overview
Problem
The provision of an organic layer as a single layer in display devices leads to defects such as lateral leakage currents between adjacent light-emitting areas, affecting display quality.
Innovation Solution
The display device incorporates a base layer with a first electrode, a pixel-defining layer, and support patterns that include a lower and upper support pattern, with the upper support pattern being made of an inorganic insulating material, to reduce deformation and improve structural stability, thereby minimizing lateral leakage currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If an organic layer is provided as a single layer shared by light-emitting areas, then device complexity is reduced, but lateral leakage current occurs between adjacent light-emitting areas
Solution Approach 1:
The single organic layer is segmented into multiple separate organic layers for different light-emitting areas. Each light-emitting area has its own dedicated organic layer (first organic layer, second organic layer, third organic layer) that is electrically isolated from adjacent areas, preventing lateral leakage current while maintaining manufacturing feasibility through sequential formation processes.
2Ease of manufacture
If support patterns are made with conventional materials, then ease of manufacture is maintained, but structural stability and deformation resistance are insufficient
Solution Approach 1:
The support pattern is constructed as a composite structure with two distinct layers: a lower support pattern made of conductive material (such as ITO or IZO) and an upper support pattern made of inorganic insulating material (such as silicon nitride or silicon oxide). This composite structure combines the electrical conductivity needed for pixel operation with the high mechanical strength and thermal stability of inorganic insulators, preventing deformation during high-temperature processes while maintaining ease of manufacture through standard sputtering and etching techniques.
Data Source
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AI summary
A display device includes a base layer, a first electrode above the base layer, a pixel-defining layer above the base layer, defining a pixel opening through which the first electrode is exposed, and including a concave area extending from the pixel opening to an inner side of the pixel-defining layer, a support pattern above the first electrode in the concave area, and including a lower support pattern between the first electrode and the pixel-defining layer, and an upper support pattern between the lower support pattern and the pixel-defining layer, one portion of the upper support pattern overlapping the lower support pattern, and another portion of the upper support pattern offset from the lower support pattern in plan view and spaced apart from the first electrode, a first light-emitting pattern above the first electrode, and a second electrode above the first light-emitting pattern.