Light Emitting Display Device Leakage Current Prevention
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Solution Overview
Problem
Light emitting display devices face issues with leakage current flowing between adjacent subpixels, leading to unwanted light emission and potential voids between subpixels.
Innovation Solution
The device incorporates electrode patterns formed as the same layers as the lower electrodes of anodes in non-emission areas between emission areas of adjacent subpixels, creating a step and preventing contact between corresponding layers of the intermediate layer and dummy patterns, thus blocking leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If common masks are used to deposit intermediate layer and dummy pattern, then manufacturing process is simplified, but leakage current flows between adjacent subpixels through common layers
Solution Approach 1:
The patent introduces a vertical height dimension by forming a step structure between emission areas and non-emission areas. The electrode pattern in non-emission areas is positioned at a different height than the intermediate layer, creating a physical separation that blocks leakage current while maintaining the benefit of common mask deposition processes.
2Reliability
If electrode patterns are formed at different heights to prevent leakage current, then reliability is improved, but device structure becomes more complex
Solution Approach 1:
The patent merges the function of leakage current prevention with the existing emission area definition structure. The step structure is created by extending existing electrode patterns into non-emission areas rather than adding separate blocking structures, thereby preventing leakage current without significantly increasing device complexity.
3Reliability
If intermediate layer and dummy pattern are positioned at different heights, then leakage current is blocked, but voids may occur between adjacent subpixels
Solution Approach 1:
The patent applies different structural characteristics to different regions: in emission areas, the intermediate layer contacts the electrode at normal height for proper light emission; in non-emission areas, a step structure creates height difference to block leakage current. This localized differentiation prevents leakage current while avoiding void formation through precise regional control.
Data Source
AI summary
A light emitting display device including a substrate including first and second subpixels, a first insulating layer on the substrate, a first anode including first lower and upper electrodes on the first insulating layer at the first subpixel, a second anode including second lower and upper electrodes spaced from each other by the first insulating layer at the second subpixel, a first electrode pattern at non-emission areas and spaced from the first lower electrode, and a second electrode pattern spaced from the second lower electrode to overlap the first electrode pattern. A first vertical distance from an upper surface of the substrate to an upper surface of the first electrode pattern may be greater than a second vertical distance from the upper surface of the substrate to an upper surface of the first upper electrode.