OLED Light-Emitting Element Structure to Suppress Short Circuits
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Display devices, particularly those using organic light-emitting diodes (OLEDs) and liquid crystal displays (LCDs), face challenges with short-circuit defects that affect their reliability and performance.
Innovation Solution
The proposed display device incorporates a substrate with defined subpixels, each containing a light-emitting element with a specific semiconductor layer structure. The light-emitting element has an omega shape, with a first semiconductor layer featuring a flat top surface and a protruding part in contact with the light-emitting layer. This configuration, combined with planarization layers, helps disconnect the first connection electrode from the top surface of the light-emitting element, minimizing the risk of short-circuit defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the first connection electrode covers the entire side surface of the light-emitting element, then the electrical connection is improved, but the risk of short-circuit defects increases
Solution Approach 1:
The first connection electrode is segmented into two distinct parts: a first electrode part on the first semiconductor layer and a second electrode part on the second semiconductor layer. This segmentation prevents the electrode from continuously covering the entire side surface, thereby reducing short-circuit risk while maintaining electrical connection functionality through separate contact points.
Solution Approach 2:
The connection electrode structure implements local quality by having different electrode parts at different locations - the first electrode part contacts the first semiconductor layer at a specific location while the second electrode part contacts the second semiconductor layer at another location. This localized electrode arrangement ensures electrical connection where needed while avoiding continuous coverage that causes short-circuits.
2Ease of manufacture
If the semiconductor layers are formed with uniform thickness, then the manufacturing process is simplified, but the self-alignment capability is reduced
Solution Approach 1:
The first and second semiconductor layers are designed with asymmetric thicknesses, where the first semiconductor layer has a different thickness than the second semiconductor layer. This asymmetry creates distinct height levels that enable self-alignment during the stacking process, allowing the light-emitting element to automatically position itself correctly without requiring complex alignment procedures.
Solution Approach 2:
The invention utilizes the vertical dimension (height difference between first and second semiconductor layers) to achieve self-alignment. By creating a thickness difference in the semiconductor layers, the structure gains a vertical dimension cue that guides horizontal positioning during assembly, transforming a 2D alignment problem into a 3D self-positioning solution.
Data Source
AI summary
A display device includes a substrate on which a plurality of subpixels is defined, and a plurality of light-emitting elements respectively disposed in the plurality of subpixels. Each of the plurality of light-emitting elements includes a first semiconductor layer, a light-emitting layer on the first semiconductor layer, and a second semiconductor layer on the light-emitting layer. The first semiconductor layer includes a first part having a flat top surface, and a second part protruding upward from the first part and being in direct contact with a bottom surface of the light-emitting layer. An area of a top surface of the second semiconductor layer is larger than an area of a bottom surface of the second semiconductor layer.