Micro LED Adhesive Interconnect Structure Against Heat and Impact

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Solution Overview

Problem

Micro LEDs fixed by solder on a pixel array substrate are prone to fall off due to heat or impact during manufacturing processes, leading to operational failures.

Innovation Solution

A display device design that incorporates a circuit substrate, a first light-emitting diode, an anisotropic conductive adhesive structure, and a conductive connection element, where the adhesive structure is positioned to cover the lower electrode and light-emitting layer of the diode, and a conductive connection element connects the upper electrode to the circuit substrate, reducing the likelihood of diode detachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If solder is used to fix micro LEDs to the pixel array substrate, then electrical connection is achieved, but the micro LEDs are likely to fall off due to heat or impact during subsequent processes

Engineering Contradiction:

Improvestability of micro LED connectionVSAvoidsensitivity to heat and impact

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces an anisotropic conductive adhesive layer as an intermediary between the micro LED and the substrate. This adhesive layer serves as a mediator that provides both mechanical support (resisting heat and impact) and electrical connection, eliminating the vulnerability of direct solder connections to thermal and mechanical stress

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs a composite structure combining the anisotropic conductive adhesive layer with the substrate and micro LED. This composite material approach integrates the adhesive's flexibility and thermal resistance with the electrical conductivity requirements, creating a robust connection that withstands manufacturing process stresses

Inventive Principle:

Principle #40Composite materials

2Reliability

If the anisotropic conductive adhesive structure is positioned to cover the lower electrode and light-emitting layer, then the LED is securely fixed, but the structure complexity increases

Engineering Contradiction:

Improvefixation stability of LEDVSAvoidstructural complexity of adhesive arrangement

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the adhesive application into specific functional zones: the anisotropic conductive adhesive layer is positioned to cover the lower electrode and light-emitting layer areas where fixation is most critical. This segmented approach provides secure fixation only where needed, rather than applying adhesive uniformly across the entire device, thereby reducing unnecessary structural complexity

Inventive Principle:

Principle #1Segmentation

3Reliability

If conductive connection element is used to connect upper electrode to circuit substrate, then electrical connection is established, but the manufacturing difficulty increases due to potential short circuits and breakage

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidmanufacturing difficulty of conductive connection

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The anisotropic conductive adhesive layer serves as an intermediary that facilitates the connection between the upper electrode and the circuit substrate. This adhesive mediator provides a controlled conductive path that eliminates the risk of short circuits and breakage associated with direct conductive connection elements, thereby simplifying the manufacturing process while maintaining connection reliability

Inventive Principle:

Principle #24Intermediary (Mediator)

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 anisotropic conductive adhesive structure effectively secures the LEDs to the substrate, minimizing the risk of detachment and simplifies the conductive connection process by preventing short circuits and breakage.

Implementation Method 1

an anisotropic conductive adhesive structure, where the adhesive structure is positioned to cover the lower electrode and light-emitting layer of the diode

Methodology Applied

Scientific EffectAnisotropic conduction: Anisotropy

Implementation Method 2

The anisotropic conductive adhesive structure effectively secures the LEDs to the substrate

Methodology Applied

Scientific EffectAdhesive bonding: Adhesive

Implementation Method 3

A light-emitting diode (LED) is an electroluminescent semiconductor element

Methodology Applied

Scientific EffectElectroluminescence: Electroluminescence

Data Source

PatentUS12543421B2Display device and manufacturing method thereof

Publication Date: 2026.02.03 AU OPTRONICS CORP

AI summary

A display device including a circuit substrate, a first light-emitting diode, an anisotropic conductive adhesive structure, and a conductive connection element is provided. The first light-emitting diode is located above the circuit substrate. The anisotropic conductive adhesive structure is located between the circuit substrate and the first light-emitting diode, and electrically connects the circuit substrate to a lower electrode of the first light-emitting diode. The conductive connection element electrically connects the upper electrode of the first light-emitting diode to the circuit substrate. A portion of the conductive connection element is located on the anisotropic conductive adhesive structure.