Micro LED Contact Edge Spacing for Leakage Prevention

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Solution Overview

Problem

Mini and micro light-emitting diodes face issues with uneven current spreading and current leakage due to defects in sidewalls, leading to reduced luminous efficiency.

Innovation Solution

A display device design with a light-emitting unit featuring a transporting layer and a conductive layer where the distance between the edge of the contact region and the edge of the transporting layer is greater than or equal to 0.1 μm, along with a current blocking layer on the side surfaces to prevent electron capture and leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the contact region edge is positioned close to the transporting layer edge to maximize current conduction path, then current spreading efficiency improves, but current leakage through sidewall defects increases

Engineering Contradiction:

Improvecurrent spreading efficiencyVSAvoidcurrent leakage prevention

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

An insulating layer is introduced as an intermediary between the contact region and the transporting layer sidewall. This insulating layer acts as a mediator that prevents direct electrical contact between the conductive contact region and the defective sidewall, thereby blocking current leakage paths while allowing the contact region to extend close to the transporting layer edge for optimal current spreading

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The harmful factor (sidewall defects) is isolated from the current conduction path by extracting the sidewall region from the electrical pathway. The insulating layer effectively removes the defective sidewall from the current flow, preventing electron capture at sidewall defects while maintaining the intended current spreading through the transporting layer

Inventive Principle:

Principle #2Taking out (Extraction)

2Loss of energy

If the contact region extends to the edge of the transporting layer to improve current distribution, then luminous efficiency improves, but short circuit risk increases

Engineering Contradiction:

Improveluminous efficiencyVSAvoidshort circuit prevention

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The insulating layer serves as a protective intermediary that allows the contact region to extend to or near the transporting layer edge for optimal current distribution and luminous efficiency, while simultaneously preventing short circuits by electrically isolating the conductive contact region from the sidewall structures

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If the sidewall is left exposed to allow current conduction, then current flow through the light-emitting area improves, but electron capture at defects increases

Engineering Contradiction:

Improvecurrent flow efficiencyVSAvoidelectron capture at sidewall defects

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The potentially harmful sidewall structure is converted into a beneficial configuration by coating it with an insulating layer. This transformation turns the sidewall from a source of electron capture defects into a protected boundary that guides current flow through the intended path while preventing harmful electron capture

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The insulating layer acts as a mediator between the current-carrying contact region and the sidewall structure, allowing the sidewall to maintain its structural role while preventing its defective surface from capturing electrons and creating leakage paths

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11011677B2Display device

Publication Date: 2021.05.18 INNOLUX CORP

AI summary

A display device is provided. The display device includes a substrate and a light-emitting unit disposed on the substrate. The light-emitting unit includes a transporting layer having a first semiconductor region and a second semiconductor region, and a conductive layer having a contact region that is in contact with the second semiconductor region. The distance between an edge of the contact region and an edge of the transporting layer is greater than or equal to 0.1 μm.