Micro-LED Assembly Electrode Layout for Higher DEP Lighting Rate
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Solution Overview
Problem
The self-assembly method using dielectrophoresis (DEP) for micro-LED displays faces challenges with low self-assembly rates due to non-uniform DEP force and reduced electrical contact characteristics, leading to lower lighting rates and increased transfer error rates in large-area displays.
Innovation Solution
The implementation of a semiconductor light emitting device with a side electrode connected to the first conductivity type semiconductor layer and a panel electrode, along with an assembly barrier wall with a contact hole exposing the assembly electrodes, enhances the electrical contact area and improves the uniformity of the DEP force, thereby increasing the lighting rate and reducing transfer errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If self-assembly method using dielectrophoresis (DEP) is used to transfer micro-LEDs, then transfer speed is improved, but transfer error rate increases and lighting rate decreases
Solution Approach 1:
The patent introduces a side electrode structure that creates a non-uniform electric field distribution, concentrating the DEP force at specific locations (the side surface of the micro-LED) to achieve both rapid transfer and precise positioning. This local concentration of electric field intensity resolves the contradiction by making the DEP force spatially selective rather than uniform.
Solution Approach 2:
The patent adds a lateral dimension to the electrode configuration by introducing side electrodes that contact the side surface of the micro-LED. This dimensional extension allows the electric field to act from multiple directions (top and side), improving both transfer speed and positioning accuracy simultaneously, thereby increasing lighting rate while maintaining high productivity.
2Speed
If DEP force is used for self-assembly, then assembly speed increases, but uniformity of DEP force control decreases causing tilting
Solution Approach 1:
The patent employs an asymmetric electrode configuration where side electrodes are positioned to contact the side surface of the micro-LED at specific angles and locations. This asymmetric arrangement creates a controlled non-uniform electric field that generates sufficient DEP force for rapid assembly while simultaneously providing restoring forces that prevent tilting and ensure precise vertical positioning.
Solution Approach 2:
The side electrode structure serves multiple functions simultaneously: it generates DEP force for rapid assembly, provides lateral positioning control to prevent tilting, and ensures uniform electrical contact. This multi-functionality resolves the contradiction by making a single structural element responsible for both speed and precision requirements.
3Productivity
If rapid transfer of millions of micro-LEDs is implemented, then transfer speed improves, but transfer yield decreases due to increased transfer error rate
Solution Approach 1:
The side electrode configuration creates a self-correcting mechanism where the electric field distribution automatically adjusts to maintain optimal DEP force on each micro-LED during transfer. This feedback-like behavior ensures that even at high transfer speeds, each device is positioned accurately, maintaining high transfer yield across millions of devices without requiring external monitoring or adjustment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration significantly increases the lighting rate and improves electrical contact characteristics by expanding the electrical contact area between the semiconductor light emitting device and the panel electrode, addressing the issues of low self-assembly rates and transfer errors in large-area displays.
Implementation Method 1
a self-assembly method using dielectrophoresis (DEP)
Data Source
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AI summary
A display device according to an embodiment can include a first assembly electrode and a second assembly electrode disposed to be spaced apart from each other on a substrate, a first insulating layer disposed on the first assembly electrode and the second assembly electrode, a semiconductor light emitting device having an assembly barrier wall including a predetermined assembly hole and disposed on the first insulating layer, a side electrode electrically connected to a first side surface of the semiconductor light emitting device, and a second panel electrode electrically connected to the second conductivity type semiconductor layer.