Micro-LED Bump Structure for Flexible Room-Temperature Transfer

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Solution Overview

Problem

Existing display technologies, such as LCDs and AMOLEDs, face issues with slow response time, limited flexibility, and short lifespan, while micro-LED displays face challenges in high-speed transfer processes that are difficult and costly.

Innovation Solution

A display apparatus using a semiconductor light-emitting device with a cantilever-shaped bump structure that allows for elastic bending, enabling room-temperature transfer and simplifying the wiring process by using anisotropic conductive films for electrical connections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If micro-LED transfer process is implemented, then display performance is improved, but transfer difficulty and cost increase

Engineering Contradiction:
Improvedisplay performanceVSAvoidtransfer process difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The bump structure is designed with dynamic flexibility, allowing it to bend and deform during the transfer process. This dynamic characteristic enables the bump to adapt to positioning variations and facilitate easier transfer of micro-LEDs without requiring precision alignment, thereby reducing transfer difficulty while maintaining display performance

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the physical parameters of the connection structure by using a flexible bump instead of a rigid wire. The bump can change its shape and position during transfer, allowing for room-temperature processing and simplified transfer procedures, which directly addresses the transfer difficulty and cost issues

Inventive Principle:
Principle #35Parameter changes

2Reliability

If rigid wire bonding is used, then electrical connection is achieved, but flexibility and adaptability are reduced

Engineering Contradiction:
Improveelectrical connectionVSAvoidflexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The bump structure replaces rigid wire bonding with a flexible, deformable connection element. This dynamic structure can bend and adapt to different positions, enabling the same electrical connection function to work with flexible displays and various display configurations, thereby significantly improving adaptability while maintaining connection reliability

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention uses a flexible bump structure instead of rigid wire bonds. This flexible connection element can deform and adapt to different geometries, enabling use in flexible displays and various mounting configurations, directly addressing the flexibility and adaptability requirements

Inventive Principle:
Principle #30Flexible shells and thin films

3Manufacturing precision

If complex transfer processes are used, then micro-LED positioning precision is improved, but process complexity increases

Engineering Contradiction:
Improvemicro-LED positioning precisionVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The bump structure is pre-formed with specific geometric characteristics that facilitate self-alignment during transfer. The preliminary preparation of the flexible bump structure enables simple transfer processes while maintaining positioning precision, as the bump's physical properties guide the micro-LED into the correct position without requiring complex alignment procedures

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The flexible bump structure enables self-alignment and self-positioning during the transfer process. The bump's deformability allows it to automatically adjust to achieve proper positioning, eliminating the need for complex external alignment mechanisms and reducing overall process complexity while maintaining manufacturing precision

Inventive Principle:
Principle #25Self-service

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

Facilitates high-speed transfer of micro-LEDs with improved flexibility and reduced process complexity, allowing for the creation of flexible, high-definition displays with enhanced durability and image quality.

Implementation Method 1

the bump may have elasticity with respect to the bending of the free end

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3879577B1Display apparatus using semiconductor light-emitting device
Publication Date: 2025.11.05 LG ELECTRONICS INC
  • EP3879577B1 patent drawingFigure 1
  • EP3879577B1 patent drawingFigure 2
  • EP3879577B1 patent drawingFigure 3A~3B

AI summary

The present invention relates to a display apparatus and, specifically, to a display apparatus using a semiconductor light-emitting device. The display apparatus according to the present invention comprises: at least one horizontal semiconductor light-emitting device comprising a first conductive electrode and a second conductive electrode; a first wiring and a second wiring arranged to be apart from each other on a substrate and electrically connected to the first conductive electrode and the second conductive electrode, respectively; a first bump formed between the first wiring and the first conductive electrode; and a second bump formed between the second wiring and the second conductive electrode, wherein at least one of the first bump and the second bump protrudes from the corner of any one of the first wiring and the second wiring towards the other.