Bar-Type LED Electrode Layout for Higher Light Extraction

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Solution Overview

Problem

Existing technologies face challenges in fabricating light emitting devices with bar type LEDs that minimize defects while improving light efficiency.

Innovation Solution

A light emitting device is designed with a substrate having unit light emitting regions, featuring first to fourth insulating layers, and including light emitting elements with reflective electrodes and contact electrodes, along with a conductive pattern to enhance light emission and minimize defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional fabrication methods are used for bar type LEDs, then manufacturing process is simpler, but light efficiency is reduced and defects increase

Engineering Contradiction:
Improvelight efficiencyVSAvoidstructure complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The device is divided into multiple unit light emitting regions, each containing a bar type LED with specific structural components (reflective electrodes, contact electrodes, insulating layers). This segmentation allows optimization of light emission in each unit while managing overall device complexity through modular design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the device have specialized structures: reflective electrodes are positioned at specific locations to redirect light, insulating layers are placed between conductive elements to prevent short circuits, and contact electrodes are configured for optimal electrical connection. This local optimization improves light efficiency without requiring complete redesign of the entire device.

Inventive Principle:
Principle #3Local quality

2Reliability

If conventional fabrication methods are used for bar type LEDs, then manufacturing process is simpler, but defect rate increases

Engineering Contradiction:
Improvedefect minimizationVSAvoidfabrication difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Insulating layers are formed between conductive elements during the fabrication process to prevent short circuits before they occur. Reflective electrodes are positioned and configured in advance to ensure proper light reflection. These preliminary actions prevent defects during operation and reduce the need for post-fabrication repairs.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Insulating layers serve as intermediary elements between conductive components (reflective electrodes and contact electrodes), preventing direct contact that would cause short circuits. This intermediary structure improves reliability by isolating conductive elements while allowing the device to be fabricated using standard semiconductor processing techniques.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Area of moving object

If bar type LEDs are made smaller for pixel-scale applications, then display resolution is improved, but light emission efficiency decreases

Engineering Contradiction:
ImproveLED sizeVSAvoidlight emission efficiency
Core Design Contradiction:
Area of moving objectVSIllumination intensity

Solution Approach 1:

Even in miniaturized bar type LEDs, reflective electrodes are positioned at specific locations to maximize light reflection within the small structure. Contact electrodes are configured for optimal electrical connection in the reduced size format. This local optimization ensures that light emission efficiency is maintained despite the smaller overall device area.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The reflective electrodes and contact electrodes are arranged in specific three-dimensional configurations within the miniaturized LED structure. By optimizing the spatial arrangement in multiple dimensions, the device maintains effective light emission and electrical connection despite the reduced scale, enabling pixel-scale applications with acceptable light efficiency.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 proposed solution effectively minimizes defects and improves light efficiency in light emitting devices with bar type LEDs, enabling their use in display devices.

Implementation Method 1

a first reflective electrode, on the first partition wall and a second reflective electrode, on the second partition wall

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3787027B1Light emitting device, display device with the same, and method of manufacturing said display device
Publication Date: 2025.04.16 SAMSUNG DISPLAY CO LTD
  • EP3787027B1 patent drawingFigure 1~2A
  • EP3787027B1 patent drawingFigure 2B
  • EP3787027B1 patent drawingFigure 3

AI summary

A light emitting device may include: a substrate including a plurality of unit light emitting regions; and first to fourth insulating layers sequentially on the substrate. Each of the unit light emitting regions may include: at least one light emitting element on the first insulating layer, the at least one light emitting element having a first end portion and a second end portion in a length direction thereof; first and second partition walls on the substrate, and the first and second partition walls being spaced apart from each other; a first reflective electrode on the first partition wall and a second reflective electrode on the second partition wall; a first contact electrode on the first reflective electrode, the first contact electrode connecting the first reflective electrode and the first end portion of the light emitting element; a second contact electrode on the second reflective electrode, the second contact electrode connecting the second reflective electrode and the second end portion of the light emitting element; and a conductive pattern provided between the first insulating layer and the first contact electrode, the conductive pattern surrounding the first and second reflective electrodes when viewed on a plane.