Micro-LED Assembly Hole Wiring for Uniform DEP Positioning
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Solution Overview
Problem
Large-area micro-LED displays face challenges in quickly and accurately transferring millions of micro-LEDs due to high transfer error rates, leading to low yield and uneven lighting rates.
Innovation Solution
A display device design featuring a substrate with first and second assembling wirings, an insulating layer, and a partition wall with an assembly hole, where the second assembling wiring is disposed at the center of the assembly hole with a narrower width than the hole, allowing for uniform DEP force distribution and precise positioning of micro-LEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If self-assembly method is used to transfer micro-LEDs, then transfer speed is improved, but transfer error rate increases
Solution Approach 1:
The patent introduces a self-assembling substrate with specifically designed assembly holes and positioning structures that act as intermediaries to guide micro-LEDs to their correct positions. The substrate includes reference marks and alignment features that mediate between the self-assembly process and precise positioning requirements, enabling high-speed transfer while maintaining low error rates through automated optical alignment.
Solution Approach 2:
The patent replaces traditional mechanical pick-and-place systems with a self-assembly approach where micro-LEDs automatically position themselves on the substrate through electrostatic or chemical attraction to the assembly holes. This substitution of mechanical transfer with field-based self-assembly enables faster processing while the positioning structures ensure accurate placement.
2Productivity
If DEP force is used for self-assembly, then assembly speed is improved, but uniformity of DEP force decreases
Solution Approach 1:
The patent designs the substrate with locally optimized assembly hole structures and reference mark patterns that create uniform electric field distributions in critical positioning areas. The assembly holes are strategically positioned and dimensioned to ensure consistent DEP force exposure for all micro-LEDs, while reference marks provide localized alignment cues that compensate for any field variations.
Solution Approach 2:
The patent structures the substrate and assembly holes to create equipotential regions during the DEP self-assembly process, ensuring that all micro-LEDs experience uniform force conditions. The reference marks and assembly hole arrangements are designed to minimize electric field gradients, enabling simultaneous and uniform assembly across the entire substrate area.
3Productivity
If DEP force is used for self-assembly, then assembly speed is improved, but tilting of semiconductor light-emitting device occurs
Solution Approach 1:
The patent introduces reference marks and alignment structures on the substrate that act as intermediaries to guide the orientation and positioning of micro-LEDs during self-assembly. These features mediate between the DEP force field and the micro-LED orientation, ensuring that devices assemble in the correct orientation with proper electrical contact alignment, preventing tilting while maintaining high assembly rates.
4Area of stationary object
If micro-LEDs are transferred to large display, then display area is increased, but transfer yield decreases
Solution Approach 1:
The patent divides the large display into multiple substrates or modules, each with its own set of assembly holes and reference marks. This segmentation allows the self-assembly process to be applied to manageable sections while maintaining consistent positioning accuracy across the entire large display area. Each substrate can be independently assembled with high yield, and the modular structure enables easy replacement of any defective sections.
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 design enhances the self-assembly rate and yield by ensuring correct positioning of micro-LEDs within the assembly holes, improves lighting rates by preventing electrical contact failures, and maintains uniform lighting across pixels and sub-pixels.
Implementation Method 1
a self-assembly type transfer process using dielectrophoretic (DEP) force
Data Source
AI summary
The display device can include a substrate, a first assembling wiring on the substrate, a second assembling wiring on the first assembling wiring, an insulating layer between the first assembling wiring and the second assembling wiring, a partition wall disposed on the second assembling wiring and having an assembly hole, and a semiconductor light-emitting device in the assembly hole. A part of the second assembling wiring can be disposed at a center of the assembly hole, and a width of a part of the second assembling wiring can be smaller than a diameter of the assembly hole.