Micro-LED Insulating Taper Structure for Short-Free Electrode Transfer

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Solution Overview

Problem

The challenge lies in efficiently transferring and accurately positioning micro-LED elements onto a display device substrate without defects, such as misalignment or flipping, which increases production costs and defect rates due to the complexity of the transfer process and the high cost of semiconductor substrates.

Innovation Solution

A micro-LED element with an inverted taper-shaped structure between its n-type and p-type electrodes, made of an insulating material, is designed to minimize electrical connection defects during the transfer and placement process, ensuring stable electrode connections even if misalignment occurs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If micro-LED elements are transferred using conventional methods, then the transfer process becomes complex and costly, but manufacturing precision and reliability deteriorate due to misalignment and flipping defects

Engineering Contradiction:
Improvetransfer process complexityVSAvoidpositioning accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by pre-forming the inverted taper structure on the micro-LED element before the transfer process. This pre-prepared geometric feature ensures that during transfer, the element self-aligns and self-orients correctly on the substrate, eliminating the need for complex positioning systems and reducing misalignment defects.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The inverted taper structure enables self-service functionality during transfer. The geometric shape causes the micro-LED element to automatically self-align and self-orient on the substrate through mechanical interlocking, without requiring external alignment systems or complex transfer mechanisms, thereby simplifying the manufacturing process.

Inventive Principle:
Principle #25Self-service

2Productivity

If the transfer process is simplified to reduce costs, then productivity increases, but reliability deteriorates due to higher defect rates

Engineering Contradiction:
Improveproduction efficiencyVSAvoiddevice reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent changes the geometric parameter of the electrode structure by introducing an inverted taper shape. This parameter change creates a mechanical interlocking feature that maintains reliable electrical connections even with simple transfer processes, allowing high productivity without sacrificing reliability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The inverted taper structure introduces asymmetry to the otherwise symmetric electrode geometry. This asymmetric feature provides directional guidance during transfer, ensuring correct orientation and positioning of the micro-LED element, thereby maintaining high reliability with simplified transfer processes.

Inventive Principle:
Principle #4Asymmetry

3Ease of manufacture

If conventional electrode structures are used, then manufacturing is simpler, but electrical connection stability deteriorates due to misalignment during transfer

Engineering Contradiction:
Improvestructure fabricationVSAvoidelectrode alignment
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The inverted taper structure is pre-formed during the semiconductor fabrication process before transfer. This preliminary formation of the geometric feature ensures that alignment is achieved automatically during transfer, maintaining electrical connection stability without adding complex post-fabrication alignment steps.

Inventive Principle:
Principle #10Preliminary action

4Reliability

If the inverted taper structure is added to the LED element, then electrode connection stability improves, but device complexity increases

Engineering Contradiction:
Improveelectrode connection stabilityVSAvoidstructural complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The inverted taper structure merges multiple functions into a single geometric feature: it provides mechanical support, enables self-alignment, ensures correct orientation, and maintains electrical connection stability. This consolidation reduces the need for separate alignment features and complex structures, actually simplifying the overall device design while improving reliability.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3496143B1Light-emitting device and display device using the same
Publication Date: 2024.05.22 LG DISPLAY CO LTD
  • EP3496143B1 patent drawingFigure 1~2
  • EP3496143B1 patent drawingFigure 3~4B
  • EP3496143B1 patent drawingFigure 5A~5B

AI summary

Disclosed herein are a light-emitting device that can improve the process stability during the process of disposing the light-emitting device, and a display device including the same. A light-emitting device includes the n-type semiconductor layer and the p-type semiconductor layer, and a structure is disposed so as to minimize electrical short between electrodes even if the light-emitting device is misaligned. The structure may have at least one side surface in an inverted taper shape and may be disposed between electrodes to minimize a short-circuit therebetween during the process of connecting the electrodes.