Micro-LED Assembly Substrate with Floating Electrode DEP Control

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The self-assembly method for micro-LED displays faces challenges with low transfer rates due to non-uniform DEP force, leading to assembly errors and deteriorated electrical contact characteristics, particularly when using DEP force for assembly.

Innovation Solution

The assembly substrate structure includes a first metal layer that functions as a floating electrode during assembly, ensuring uniform DEP force distribution and symmetric electrode arrangement, which enhances the assembly rate and maintains electrical contact integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If DEP force is used for self-assembly, then assembly speed is improved, but non-uniformity of DEP force causes low self-assembly rate and transfer errors

Engineering Contradiction:

Improveassembly speedVSAvoidself-assembly rate

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The single assembly electrode is divided into multiple segmented electrodes arranged in an array. This segmentation allows independent control of DEP force at different locations, enabling uniform force distribution across the substrate surface and improving both assembly speed and self-assembly rate simultaneously.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the assembly electrode array are configured with specific electrode patterns and spacing to create localized DEP force fields. This local optimization ensures that each region generates appropriate DEP force for its specific assembly requirements, resolving the non-uniformity issue while maintaining high productivity.

Inventive Principle:

Principle #3Local quality

2Speed

If DEP force is used for self-assembly, then transfer speed is improved, but semiconductor light emitting devices tilt to positions outside normal assembly holes

Engineering Contradiction:

Improvetransfer speedVSAvoidassembly position accuracy

Core Design Contradiction:

SpeedVSManufacturing precision

Solution Approach 1:

The electrode array incorporates asymmetric electrode configurations and spacing patterns that generate directional DEP force components. This asymmetry is deliberately designed to counteract tilting forces and guide devices precisely into assembly holes, maintaining high transfer speed while correcting position accuracy.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The segmented electrode array creates counterbalancing DEP force fields that oppose and neutralize the tilting effect. By positioning electrodes to generate opposing force vectors, the system counterweights the unwanted lateral movement and keeps devices centered in assembly holes during high-speed transfer.

Inventive Principle:

Principle #8Anti-weight (Counterweight)

3Productivity

If DEP force is used for assembly, then self-assembly rate is improved, but electrical contact characteristics deteriorate due to leaning of semiconductor light emitting devices

Engineering Contradiction:

Improveself-assembly rateVSAvoidelectrical contact characteristics

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The segmented electrode array is configured to apply preliminary corrective DEP forces during the approach phase of assembly. This preliminary action prevents leaning from developing in the first place, ensuring devices maintain proper orientation throughout the assembly process and achieve reliable electrical contact from the start.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The electrode array configuration enables real-time adjustment of DEP force distribution based on device position and orientation. This feedback mechanism detects leaning tendencies and automatically adjusts local electrode activation to correct the deviation, maintaining both high assembly rate and reliable electrical contact.

Inventive Principle:

Principle #23Feedback

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 structure improves the self-assembly rate and electrical contact characteristics by stabilizing the DEP force, allowing for high-resolution micro-LED displays with reduced transfer errors and improved yield.

Implementation Method 1

DEP force is required for self-assembly

Methodology Applied

Scientific EffectDielectrophoresis (DEP): Electrophoresis

Data Source

PatentUS12525593B2Assembly substrate structure of semiconductor light emitting device display device and display device including the same

Publication Date: 2026.01.13 LG ELECTRONICS INC

AI summary

Discussed is a display device including a semiconductor light emitting device. The display device according to the embodiment can include a substrate, a first assembly electrode disposed on the substrate, a second assembly electrode disposed on the first assembly electrode, an insulating layer disposed between the first assembly electrode and the second assembly electrode, a metal layer disposed on the insulating layer and disposed to vertically overlap the first assembly electrode, and an assembly wall having an assembly hole and disposed on the metal layer and the second assembly electrode.