LED Conductive Via Segmentation for Light Extraction

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Solution Overview

Problem

Conventional light emitting diodes (LEDs) face challenges in maximizing light-extraction efficiency due to electrode structures that can block the top surface of the n-type semiconductor layer, limiting the light output and electrical characteristics.

Innovation Solution

The proposed light emitting device features a conductive support member with a first and second conductive layer, a light emitting structure comprising semiconductor layers and an active layer, and insulation layers. A conductive via penetrates through the layers, with expansion parts extending into the semiconductor layers, allowing for direct electrical connection and minimizing insulation areas to enhance contact and light extraction, while the second expansion part's greater width and specific insulation layer placement optimize electrical insulation and light output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional electrode structure is used to connect conductive layers, then electrical connection is achieved, but the top surface of the n-type semiconductor layer is blocked, reducing light-extraction efficiency

Engineering Contradiction:
Improveelectrical connectionVSAvoidlight-extraction efficiency
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The conductive via is segmented into two functional parts: a first expansion part that provides electrical connection and is covered by insulation, and a second expansion part that extends into the n-type semiconductor layer to provide light extraction pathways. This segmentation allows the via to simultaneously fulfill electrical connection and light extraction functions without compromising either.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the conductive via have different properties: the first expansion part is insulated for electrical connection, while the second expansion part remains exposed to enable light extraction. The insulation layer is selectively applied only where electrical insulation is needed, leaving other areas open for light emission.

Inventive Principle:
Principle #3Local quality

2Reliability

If insulation layers are placed to ensure electrical isolation, then electrical insulation is achieved, but contact area between conductive layers and semiconductor layers is reduced

Engineering Contradiction:
Improveelectrical insulationVSAvoidcontact area
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The insulation structure is divided into two distinct layers with different functions: the first insulation layer covers only the lateral surface of the first expansion part to provide electrical isolation, while the second insulation layer is positioned between conductive layers to prevent short circuits. This segmentation ensures insulation where needed while preserving maximum contact area for electrical connection.

Inventive Principle:
Principle #1Segmentation

3Manufacturing precision

If the conductive via is made narrow to maintain structural precision, then manufacturing precision is improved, but contact area and light extraction are limited

Engineering Contradiction:
Improvevia structural precisionVSAvoidlight output
Core Design Contradiction:
Manufacturing precisionVSIllumination intensity

Solution Approach 1:

The conductive via transitions from a simple vertical structure to a multi-dimensional structure with expansion parts in the lateral direction. The via expands horizontally at specific levels (first and second expansion parts) while maintaining vertical continuity, creating a three-dimensional configuration that increases surface area for light extraction and electrical contact without compromising vertical alignment precision.

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

Data Source

PatentEP2408029B1Light emitting device
Publication Date: 2019.01.30 LG INNOTEK CO LTD
  • EP2408029B1 patent drawingFigure 1
  • EP2408029B1 patent drawingFigure 2A~2B
  • EP2408029B1 patent drawingFigure 2C~2D

AI summary

A light emitting device includes: a conductive support member (210); a first conductive layer (220) disposed on the conductive support member; a second conductive layer (240) disposed on the first conductive layer; a light emitting structure comprising a first semiconductor layer (230) disposed on the second conductive layer, a second semiconductor layer (250) disposed between the first semiconductor layer and the second conductive layer, and an active layer (260) disposed between the first semiconductor layer and the second semiconductor layer; and an insulation layer (230) disposed between the first conductive layer and the second conductive layer, wherein the first conductive layer includes a first expansion part penetrating through the second conductive layer, the second semiconductor layer and the active layer, and includes a second expansion part (220c) extending from the first expansion part and being disposed in the first semiconductor layer, wherein the insulation layer is disposed on the lateral surface of the first expansion part, and wherein the lateral surface of the second expansion part contacts with the first semiconductor layer.