Micro-LED Growth Substrate Directional Transfer

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Solution Overview

Problem

Current methods for manufacturing LED displays face challenges in achieving high resolution and large-sized displays using micro-LEDs, as they require efficient mounting of micro-LEDs on thin film transistor substrates and effective use of small-sized growth substrates, while also addressing issues of light emission efficiency and material durability, particularly in organic light emitting diode (OLED) displays which are sensitive to moisture and oxygen.

Innovation Solution

A method involving a growth substrate where micro-LED chips are grown and then transferred to a larger transfer substrate using a donor substrate, allowing for efficient arrangement and spacing of LED chips with varying directionalities to reduce boundary perception and enhance immersion, while utilizing materials like silicon, sapphire, or gallium nitride for high light emission efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If micro-LEDs are grown on a small-sized growth substrate and then transferred to a large-sized transfer substrate, then the manufacturing efficiency and productivity are improved, but the manufacturing precision and arrangement accuracy of micro-LEDs may deteriorate

Engineering Contradiction:
Improvemanufacturing efficiencyVSAvoidarrangement accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The transfer substrate is divided into multiple first regions corresponding to different directionalities. Micro-LEDs with the same directionality are grouped together and transferred to the same first region. This segmentation allows for precise control of micro-LED arrangement by directionality while maintaining high productivity through batch transfer processes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different first regions on the transfer substrate are designated for different directionalities of micro-LEDs. This local differentiation ensures that micro-LEDs are arranged according to their specific directional characteristics in appropriate regions, maintaining manufacturing precision while enabling efficient large-scale production.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If micro-LEDs with different directionalities are arranged randomly on the transfer substrate, then the manufacturing process is simplified, but boundary perception increases and user immersion deteriorates

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoiduser immersion
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The transfer substrate is pre-divided into multiple first regions before micro-LED transfer, with each region designated for a specific directionality. This preliminary arrangement ensures that micro-LEDs are placed in appropriate regions according to their directional characteristics, eliminating boundary perception issues while maintaining manufacturing simplicity through systematic organization.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The transfer substrate is asymmetrically divided into multiple first regions with different orientations, each corresponding to a specific directionality of micro-LEDs. This asymmetric design allows for optimal arrangement of micro-LEDs according to their directional properties, improving user immersion while keeping the manufacturing process straightforward through clear regional designation.

Inventive Principle:
Principle #4Asymmetry

3Temperature

If OLED displays use organic light emitting materials, then the display can be manufactured at low temperature with fast response time, but the display becomes weak to moisture and oxygen requiring complex encapsulation

Engineering Contradiction:
Improvemanufacturing temperatureVSAvoidmoisture and oxygen resistance
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent uses inorganic micro-LEDs as a replacement (copy) for organic light emitting materials. Micro-LEDs provide similar display functionality with fast response times but offer superior stability and resistance to moisture and oxygen, eliminating the need for complex encapsulation while maintaining low-temperature manufacturing advantages.

Inventive Principle:
Principle #26Copying

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 the efficient manufacturing of large-sized LED displays with improved light emission efficiency and reduced boundary perception, enhancing user immersion by effectively arranging micro-LEDs on a larger substrate with precise directional control and material selection.

Implementation Method 1

a light emitting diode (LED) display using light emitting diodes (LEDs) formed of an inorganic material... because the LEDs have high light conversion efficiency

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentEP3486946B1Growth substrate including micro-light emitting diode chips and method of manufacturing light emitting diode display using the same
Publication Date: 2023.05.24 LG DISPLAY CO LTD
  • EP3486946B1 patent drawingFigure 1
  • EP3486946B1 patent drawingFigure 2A
  • EP3486946B1 patent drawingFigure 2B

AI summary

A growth substrate including micro-light emitting diode (LED) chips and a method of manufacturing a light emitting diode display using the growth substrate are disclosed. The growth substrate includes LED chips. The LED chips are divided into n groups each including p LED chips, where each of the n and p is an integer equal to or greater than 2. At least two of the n groups are adjacent to each other. Each of the n includes a first LED chip having a directionality toward a first direction and a second LED chip having a directionality toward a second direction different from the first direction.