Magnet Unit Layout for LED Chip Self-Assembly Alignment

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Solution Overview

Problem

The self-assembly of semiconductor light emitting devices for display pixels faces challenges in controlling the direction of semiconductor light emitting device chips, leading to reduced assembly rates and increased residual chips, which result in assembly defects and the need for additional chip collection processes.

Innovation Solution

A magnet unit with a magnet body and a magnet control unit around its circumference, including spacers and focusing units made of materials like ferrite, nickel, and cobalt alloys, is used to control the magnetic field distribution, allowing for improved alignment and positioning of semiconductor light emitting devices on the assembly substrate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the transfer speed of semiconductor light emitting devices is increased to improve assembly efficiency, then productivity is improved, but the transfer error rate increases and manufacturing precision deteriorates

Engineering Contradiction:
Improveassembly rateVSAvoidtransfer accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The semiconductor light emitting device is designed to self-assemble on the display panel through magnetic field interaction. The device chip includes a magnetic layer that responds to the magnetic field from the display panel, enabling automatic positioning and assembly without manual intervention or complex external manipulation mechanisms, thus achieving high speed and high precision simultaneously

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The traditional mechanical pick-and-place system is replaced with a magnetic field-based self-assembly mechanism. Instead of using mechanical arms and grippers that limit speed and precision, the invention uses magnetic field interaction between the magnetic layer on the device chip and the magnetic field source on the display panel to achieve rapid and accurate assembly

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

2Device complexity

If conventional self-assembly methods are used without direction control, then device complexity is reduced, but manufacturing precision deteriorates due to inability to control chip direction

Engineering Contradiction:
Improveassembly system complexityVSAvoidassembly accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The magnetic field distribution on the display panel is designed with local variations to provide directional information. Specific regions of the magnetic field have different strengths or orientations, enabling the semiconductor light emitting device to not only locate its assembly position but also orient itself correctly during self-assembly, achieving high precision without complex external control mechanisms

Inventive Principle:
Principle #3Local quality

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 solution enhances the assembly rate by 2 to 3 times, reduces residual chips, and improves assembly efficiency by ensuring accurate placement and minimizing vertical magnetic field interference, thus preventing assembly defects and eliminating the need for separate chip collection.

Implementation Method 1

a magnet unit capable of controlling the direction of a semiconductor light emitting device for a display pixel

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

the magnetic field forming unit approaches the assembly substrate through vertical and horizontal movement

Methodology Applied
Scientific EffectMagnetism: Magnetism

Implementation Method 3

the semiconductor light emitting devices are adhered to the assembly surface by the magnetic field forming unit

Methodology Applied
Scientific EffectMagnetic force: Magnetism

Implementation Method 4

a step of moving a group of semiconductor light emitting device chips including magnetic materials by a large number of rotating magnet rods

Methodology Applied
Scientific EffectMagnetic force: Magnetism

Data Source

PatentEP4354501A1Magnet unit of semiconductor light emitting device for display pixel and self-assembly device using the same
Publication Date: 2024.04.17 LG ELECTRONICS INC
  • EP4354501A1 patent drawingFigure 1
  • EP4354501A1 patent drawingFigure 2
  • EP4354501A1 patent drawingFigure 3

AI summary

The embodiment relates to a magnet unit (710) of a semiconductor light emitting device for a display pixel and a self-assembly device using the same. A magnet unit (710) according to an embodiment includes a magnet body (702) and a magnet control unit (704) disposed around an outer circumference of the magnet body. The magnet control unit includes a first magnet focusing unit (704B) spaced apart from an outer circumference of the magnet body and a first spacer (704A) disposed between the magnet body (702) and the first magnet focusing unit (704B).