Organic EL Display Pixel Isolation via Bank Level Differences
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Solution Overview
Problem
Current organic EL display devices face issues with current leakage between pixels, leading to unintended light emission and difficulty in controlling the formation of organic material layers, especially when improving resolution or increasing the opening ratio of banks for enhanced light emission efficiency.
Innovation Solution
The organic EL display device incorporates a level difference part on the bank's upper surface, which divides or thins specific layers of the organic material layer, preventing current leakage between adjacent pixels while maintaining high manufacturing efficiency by sharing layers across multiple pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If layers of the organic material layer are shared in common by a plurality of pixels, then manufacturing efficiency is improved, but current leakage occurs between adjacent pixels
Solution Approach 1:
The patent divides the organic material layer into pixel-specific portions by forming level difference parts on the bank. This segmentation allows the organic material layer to be physically separated at pixel boundaries, preventing current leakage while maintaining the efficiency of shared layer formation processes across multiple pixels.
Solution Approach 2:
The patent applies different structural characteristics to different regions: the organic material layer is continuous and shared in common over multiple pixels for efficiency, but at the level difference parts corresponding to pixel boundaries, the layer is divided or thinned to create electrical isolation. This local variation in structure quality resolves the contradiction between shared manufacturing and current leakage prevention.
2Illumination intensity
If the opening ratio of the bank is increased to improve light emission efficiency, then light emission efficiency is improved, but control of organic material layer formation becomes more difficult
Solution Approach 1:
The patent performs preliminary action by forming level difference parts on the bank before depositing the organic material layer. These pre-formed structural features guide the subsequent formation of the organic material layer, ensuring that even with increased bank opening ratios, the organic material layer is automatically positioned and shaped correctly without requiring complex real-time control during deposition.
Data Source
AI summary
An organic EL display device according to an embodiment of the present invention includes: a base material; a plurality of pixels; a lower electrode which each of the plurality of pixels is provided with; an organic insulation layer which sections the plurality of pixels; an organic material layer which is disposed on the lower electrode and the organic insulation layer, and includes a plurality of layers; and an upper electrode on the organic material layer. A level difference part is positioned on an upper surface of the organic insulation layer, a first layer included in the organic material layer is divided at the level difference part, or has a thin part being thinner at the level difference part than at a position at which the first layer faces the lower electrode, and a second layer included in the organic material layer is not divided at the level difference part.