OLED Intermediate Layer Thickness Profile for Pixel Defect Reduction
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Solution Overview
Problem
The existing methods for manufacturing organic light-emitting display apparatuses using fine metal mask techniques are costly and result in defective pixels due to damage to the intermediate layer, including the emission layer, during the photo patterning process, where the protective layer's thickness decreases, allowing strippers to penetrate and cause damage.
Innovation Solution
The proposed solution involves forming an organic light-emitting display apparatus with a structured intermediate layer and protective layer configuration, where the intermediate layer includes a center area and side areas with decreasing thickness, and the protective layer is designed to maintain a minimum distance of 50 Å to 1000 Å from the opposite electrode, preventing damage by reducing the penetration of strippers and ensuring uniform thickness to minimize defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a photo patterning process is used to form the intermediate layer, then manufacturing cost is reduced compared to fine metal mask techniques, but the protective layer thickness decreases in side areas allowing strippers to penetrate and damage the intermediate layer
Solution Approach 1:
The intermediate layer is designed with different thickness characteristics in different regions: the center area has a first thickness while the side area has a second thickness that is greater than the first thickness. This local quality variation prevents stripper penetration in the side area while maintaining manufacturing efficiency through photo patterning.
Solution Approach 2:
The side area of the intermediate layer is designed with increased thickness beforehand to act as a protective barrier against stripper penetration. This prior cushioning prevents damage to the emission layer in side areas during the manufacturing process while allowing cost-effective photo patterning methods to be used.
2Reliability
If the intermediate layer thickness is increased in side areas to prevent stripper penetration, then reliability improves, but manufacturing complexity increases
Solution Approach 1:
The intermediate layer implements local quality by having different thickness characteristics in different regions. The side area has greater thickness than the center area, providing targeted protection where stripper penetration is most likely to occur without unnecessarily increasing complexity throughout the entire structure.
Solution Approach 2:
The photo patterning process itself is used to create the differential thickness profile of the intermediate layer. The process parameters and material deposition are controlled to automatically produce the required thickness variation, making the structure self-forming rather than requiring additional complex manufacturing steps.
3Ease of manufacture
If a uniform thickness protective layer is used, then ease of manufacture is improved, but defective pixels increase due to stripper penetration in side areas
Solution Approach 1:
The intermediate layer is designed with local quality variation where the side area thickness is intentionally greater than the center area thickness. This creates a protective barrier in side areas that prevents stripper penetration and resulting pixel defects, while the overall structure remains compatible with standard photo patterning manufacturing processes.
Solution Approach 2:
The increased thickness in the side area of the intermediate layer serves as a beforehand cushion against stripper penetration. This prior protective measure prevents damage to the emission layer during manufacturing, thereby reducing pixel defect rates without requiring complex additional protective measures.
Data Source
AI summary
An organic light-emitting display apparatus including a substrate; a pixel electrode on the substrate; a pixel-defining layer including an opening exposing at least a portion of the pixel electrode; an intermediate layer including a center area on the pixel electrode and a side area extending from the center area and arranged on the pixel-defining layer, the intermediate layer including one or more common layers and an emission layer; a protective layer covering top surfaces of the center area and the side area of the intermediate layer and exposing at least a portion of the pixel-defining layer; and an opposite electrode spaced apart from the intermediate layer by the protective layer and arranged on the protective layer and portions of the pixel-defining layer, the portions being exposed by the protective layer.