MicroLED Self-Assembly Using Magnetic and Electric Field Transfer

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Solution Overview

Problem

Current methods for manufacturing large-screen displays using semiconductor light-emitting diodes face challenges in transfer accuracy and efficiency, particularly with self-assembly technologies, which require high precision and are costly and time-consuming, especially when dealing with large numbers of microLEDs.

Innovation Solution

A method and device utilizing a combination of magnetic and electric fields to self-assemble semiconductor light-emitting diodes, allowing for precise positioning and assembly on a temporary substrate, enabling efficient transfer and reducing non-specific binding, with magnets used for assembly and re-use of remaining diodes in a fluid chamber.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If self-assembly method is used to transfer microLEDs, then transfer efficiency is improved, but transfer accuracy deteriorates

Engineering Contradiction:
Improvetransfer efficiencyVSAvoidtransfer accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

A temporary substrate is introduced as an intermediary between the microLED array and the final display substrate. The microLEDs are first self-assembled onto the temporary substrate with high efficiency, then precisely transferred to the final substrate. This mediator enables both high-throughput self-assembly and precise positioning.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The transfer process is divided into two separate stages: first, high-efficiency self-assembly onto a temporary substrate; second, precise transfer to the final display substrate. This segmentation allows each stage to optimize for its specific requirement (speed vs. precision).

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If conventional pick & place method is used, then transfer accuracy is maintained, but productivity deteriorates

Engineering Contradiction:
Improvetransfer accuracyVSAvoidtransfer efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The microLEDs perform self-assembly onto the temporary substrate through self-propulsion in fluid, eliminating the need for complex mechanical pick & place equipment. This self-service mechanism achieves high throughput while maintaining positioning accuracy through controlled fluid dynamics.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The mechanical pick & place system is replaced with a fluid-based self-propulsion system. MicroLEDs move autonomously in fluid under applied fields, substituting mechanical manipulation with field-driven motion for higher efficiency.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 approach enables high-reliability, low-cost, and quick transfer of large numbers of semiconductor light-emitting diodes onto a large-area substrate, improving transfer accuracy and yield while minimizing the effects of gravity and friction, thus facilitating the manufacture of large-area display devices with high picture quality.

Implementation Method 1

whereby the semiconductor light-emitting diodes are moved in one direction by a magnetic field

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

allows the semiconductor light-emitting diodes to be mounted at an assembly site by an electric field

Methodology Applied
Scientific EffectElectric field: Electric Field

Data Source

PatentEP3731276B1Apparatus and method for self-assembling of semiconductor light-emitting element
Publication Date: 2023.11.01 LG ELECTRONICS INC
  • EP3731276B1 patent drawingFigure 1
  • EP3731276B1 patent drawingFigure 2
  • EP3731276B1 patent drawingFigure 3~4

AI summary

The present invention relates to a device and method for self-assembling semiconductor light-emitting diodes. Particularly, a method for manufacturing a display device according to the present invention includes: feeding a substrate to an assembly site and putting semiconductor light-emitting diodes having a magnetic material into a fluid chamber; applying a magnetic force to the semiconductor light-emitting diodes so that the semiconductor light-emitting diodes move in one direction within the fluid chamber; and guiding the semiconductor light-emitting diodes to preset positions on the substrate by applying an electric field, so that the semiconductor light-emitting diodes are mounted at the preset positions while in the process of being moved.