OLED Display Leakage Blocking Layer for Color Mixing Suppression
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Solution Overview
Problem
The display device in existing technologies experiences leakage current generation due to a shorter distance between the hole transport layer and the common electrode in regions where the light-emitting layer is thinly formed, leading to issues like color mixing and display blurring, as well as reduced display efficiency.
Innovation Solution
A display device design that includes a first common charge transport layer, a first and second light-emitting layer, and a leakage blocking layer with insulating properties, where the leakage blocking layer is superimposed on adjacent end portions of the light-emitting layers, increasing the distance between the common charge transport layer and the common electrode in certain regions to prevent leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the light-emitting layer is formed thinly in certain regions (such as corner portions formed by side surface and upper surface of partition), then the manufacturing precision is improved, but a leakage current is generated due to shorter distance between hole transport layer and common electrode
Solution Approach 1:
The patent introduces a leakage blocking layer at specific locations where leakage current occurs (corner portions formed by side surface and upper surface of partition). This layer is not uniformly distributed but strategically placed only where needed, giving different regions of the device different functional properties. The leakage blocking layer has insulating properties that are locally applied to prevent leakage current while maintaining the thin light-emitting layer structure elsewhere.
Solution Approach 2:
The leakage blocking layer acts as an intermediary element between the hole transport layer and the common electrode. It is inserted at the interface where leakage current occurs, mediating the electrical interaction between these two layers. The insulating properties of this intermediary layer prevent direct charge leakage while allowing the overall device structure to function normally.
2Device complexity
If the distance between hole transport layer and common electrode is reduced in regions where light-emitting layer is thinly formed, then the device complexity is reduced, but leakage current is generated causing color mixing and display blurring
Solution Approach 1:
Instead of uniformly increasing the distance between hole transport layer and common electrode throughout the device, the patent applies the leakage blocking layer only at specific locations where leakage current occurs. This localized approach maintains overall structural simplicity while preventing display quality degradation at critical points.
3Reliability
If a leakage blocking layer is added to prevent leakage current, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The leakage blocking layer is not added uniformly across the entire device but is strategically positioned only at corner portions formed by the side surface and upper surface of the partition where leakage current occurs. This localized addition minimizes the increase in device complexity while effectively suppressing leakage current.
Solution Approach 2:
Rather than implementing a comprehensive solution that would increase complexity throughout the entire device, the patent applies the leakage blocking layer partially only where needed. This partial action approach provides sufficient leakage current suppression without unnecessarily increasing overall device complexity.
Data Source
AI summary
A display device includes a first common charge transport layer, a first light-emitting layer and a second light-emitting layer each of which is formed on the first common charge transport layer, a common electrode formed over both of the first light-emitting layer and the second light-emitting layer, and a leakage blocking layer having an insulating property, the leakage blocking layer being superimposed on two adjacent end portions of the first light-emitting layer and the second light-emitting layer in plan view, and a distance between the first common charge transport layer and the common electrode is larger in a first region where each of the first light-emitting layer and the second light-emitting layer is superimposed on the leakage blocking layer than in a second region where each of the first light-emitting layer and the second light-emitting layer is not superimposed on the leakage blocking layer.