Micro-LED Assembly Wiring Layout for Uniform DEP Transfer

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Solution Overview

Problem

Micro-LED display manufacturing faces challenges in quickly and accurately transferring micro-LEDs due to corrosion of assembly wiring and non-uniform DEP force during self-assembly, leading to assembly defects and low assembly rates.

Innovation Solution

A display device with alternately arranged first and second assembly wirings, where an insulating layer and planarization layer are used to precisely control the separation distance and prevent corrosion, utilizing clad layers resistant to corrosion and forming a uniform DEP force for improved assembly efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If self-assembly method is used to transfer micro-LEDs, then assembly rate is improved, but assembly wiring is corroded by fluid causing electrical short circuit and assembly defects

Engineering Contradiction:

Improveassembly rateVSAvoidassembly wiring corrosion resistance

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent introduces an insulating coating layer as an intermediary between the assembly wiring and the fluid environment. This coating layer acts as a protective barrier that prevents direct contact between the conductive wiring and corrosive fluid, thereby eliminating corrosion while maintaining the self-assembly process benefits

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs a sacrificial layer that is intentionally designed to be temporary and removable. This layer provides initial protection during the self-assembly process and can be selectively removed afterward, allowing for a simple and cost-effective solution to the corrosion problem without compromising the permanent structure

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Manufacturing precision

If assembly wiring spacing is reduced to increase density, then display resolution is improved, but assembly force becomes non-uniform causing assembly defects

Engineering Contradiction:

Improvedisplay resolutionVSAvoidassembly force uniformity

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent transitions from controlling only horizontal wiring spacing to incorporating vertical dimension control through multi-layer insulation structures. By stacking insulating layers at different heights, the system achieves precise three-dimensional positioning that maintains uniform assembly force even when horizontal spacing is reduced for higher resolution

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent divides the insulation system into multiple separate layers rather than using a single thick layer. This segmentation allows independent optimization of each layer's thickness and position, enabling precise control over the electrical field distribution and ensuring uniform assembly force across densely spaced wirings

Inventive Principle:

Principle #1Segmentation

3Manufacturing precision

If process margin is eliminated by precise wiring arrangement, then manufacturing precision is improved, but device complexity increases due to multiple insulation layers

Engineering Contradiction:

Improvewiring separation distance controlVSAvoidinsulation layer structure

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent designs the insulating layers to serve multiple functions simultaneously: electrical insulation between adjacent wirings, mechanical support for positioning, and spacing control for uniform assembly force. This multi-functionality reduces the need for separate dedicated structures, thereby limiting complexity increase while achieving high manufacturing precision

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

The solution enhances the assembly rate of light emitting devices by eliminating process margins, preventing corrosion, and ensuring uniform DEP force, thereby improving the manufacturing efficiency of micro-LED displays.

Implementation Method 1

a first assembly wiring and a second assembly wiring which are alternately arranged on the substrate and overlap each other... when transferring a light emitting device in a fluid, a problem arises where the assembly wiring is corroded by the fluid... during self-assembly, problems may arise where the assembly force varies depending on the spacing between assembly wirings

Methodology Applied

Scientific EffectDielectrophoresis (DEP): Electrostatic Induction

Data Source

PatentUS20250015243A1Display device comprising semiconductor light-emitting element, and manufacturing method therefor

Publication Date: 2025.01.09 LG ELECTRONICS INC

AI summary

A display device and a method of manufacturing the same according to an embodiment include a substrate, first assembly wiring and second assembly wiring alternately arranged on the substrate and overlapping each other, an insulating layer disposed between the first assembly wiring and the second assembly wiring, a planarization layer disposed on the first assembly wiring and the second assembly wiring, and having a first opening, and a light emitting device disposed inside the first opening, wherein the first electrode overlaps the first assembly wiring and the second assembly wiring. And, the first electrode is bonded to one of the first assembly wiring and the second assembly wiring.