Micro-LED Pixel Structure for DEP Assembly Direction and Contact
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Solution Overview
Problem
The self-assembly method for micro-LED displays using dielectrophoresis (DEP) faces challenges such as low self-assembly rate due to non-uniform DEP force, directional control issues of LED chips, and reduced lighting rate due to poor electrical contact characteristics between LED chip electrodes and panel electrodes.
Innovation Solution
The semiconductor light emitting device features a light emitting structure with a protruding semiconductor layer and a wide second electrode layer, which enhances the DEP force for directional control and improves electrical contact, while a dome-shaped upper semiconductor layer reduces total reflection and increases the light extraction efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a self-assembly method using DEP force is used to transfer micro-LED chips, then the transfer speed can be improved, but the self-assembly rate becomes low due to non-uniformity of DEP force
Solution Approach 1:
The patent applies local quality by creating an asymmetric electrode structure where the first electrode has a larger area than the second electrode. This asymmetric configuration generates a non-uniform electric field that produces a directional DEP force, concentrating the assembly action at specific locations to improve both transfer speed and self-assembly rate simultaneously.
Solution Approach 2:
The patent employs asymmetry by designing the first electrode with a larger area compared to the second electrode. This asymmetric electrode arrangement creates a directional electric field distribution that generates a net DEP force in a specific direction, enabling controlled self-assembly while maintaining high transfer speed.
2Area of stationary object
If micro-LED chips are self-assembled in a fluid using DEP force, then large-screen display can be implemented, but directional control of LED chips becomes difficult
Solution Approach 1:
The asymmetric electrode configuration with the first electrode having a larger area than the second electrode creates a directional electric field. This asymmetric field distribution generates a net DEP force that naturally guides micro-LED chips in a specific direction, solving the directional control problem while enabling large-screen display implementation.
Solution Approach 2:
The patent changes the geometric parameters of the electrodes, specifically making the first electrode area larger than the second electrode area. This parameter modification alters the electric field distribution and DEP force characteristics, providing directional control capability for micro-LED chip self-assembly in fluid.
3Speed
If micro-LED chips are transferred quickly to a large display, then the transfer speed is improved, but the transfer error rate increases and transfer yield is lowered
Solution Approach 1:
The asymmetric electrode structure creates a localized directional DEP force through the non-uniform electric field. This localized force concentration guides micro-LED chips precisely to their target positions, maintaining high transfer accuracy even at increased transfer speeds, thereby improving transfer yield.
4Device complexity
If LED chips are assembled without directional control, then the assembly process is simplified, but electrical disconnection defects occur in subsequent wiring processes
Solution Approach 1:
The asymmetric electrode design with unequal electrode areas creates a directional DEP force that automatically orients LED chips during self-assembly. This directional control ensures proper alignment of n-type and p-type electrodes with corresponding wiring, preventing electrical disconnection defects without significantly complicating the assembly process.
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 enables proper assembly direction control, increases assembly speed, improves light extraction efficiency, and enhances electrical contact characteristics, thereby addressing the low self-assembly rate and lighting rate issues in micro-LED displays.
Implementation Method 1
the self-assembly method using dielectrophoresis (DEP) has been attempted, but there is a problem in that the self-assembly rate is low due to the non-uniformity of the DEP force
Implementation Method 2
the self-assembly method using DEP force of internal technology includes the step of first moving the LED chip to the assembly hole area with the magnetic force of the magnet
Data Source
AI summary
The embodiment relates to a semiconductor light emitting device for a display pixel and a display device including the same. A semiconductor light emitting device for a display pixel according to an embodiment can include a light emitting structure including a first conductivity type semiconductor layer, a second conductivity type semiconductor layer and an active layer disposed therebetween, a passivation layer disposed on the light emitting structure, and a second electrode layer disposed under the light emitting structure. The light emitting structure may include a rounding semiconductor layer in which an upper surface thereof is partially rounded.