LED Structure with Support and Adhesion Layers for Breakage Prevention

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Solution Overview

Problem

The fabrication of light emitting diodes (LEDs) often experiences breakage or lift-off phenomena due to poor adhesion forces between the light emitting semiconductor layer and the ohmic contact layer, or between the ohmic contact layer and the reflection layer.

Innovation Solution

A light emitting device structure is developed with a support layer and an adhesion layer to enhance the adhesion force between the light emitting semiconductor layer and the ohmic contact layer, and between the ohmic contact layer and the reflection layer, using materials like GaN or Zn for the support layer and Ni, Pt, Ti, AZO, or IZO for the adhesion layer, along with a conductive substrate and a reflection layer to improve the structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a conventional LED fabrication process is used without additional support and adhesion layers, then the fabrication process is simpler, but the adhesion force between layers is poor causing breakage and lift-off

Engineering Contradiction:
Improveadhesion forceVSAvoidfabrication process complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent introduces a support layer and an adhesion layer as intermediary structures between the light emitting semiconductor layer and the ohmic contact layer/reflection layer. The support layer (e.g., GaN, Zn) provides mechanical reinforcement, while the adhesion layer (e.g., Ni, Pt, Ti, AZO, IZO) creates strong bonding interfaces, thereby mediating the weak adhesion problem without fundamentally changing the fabrication process complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs composite material structures by combining multiple materials with different properties: the support layer uses materials like GaN or Zn for structural strength, while the adhesion layer uses materials like Ni, Pt, Ti, AZO, or IZO for bonding capability. This composite approach solves the adhesion problem by leveraging the complementary properties of different materials

Inventive Principle:
Principle #40Composite materials

2Reliability

If the LED structure uses direct contact between light emitting semiconductor layer and ohmic contact layer, then the device structure is simpler, but breakage occurs during fabrication due to poor adhesion

Engineering Contradiction:
Improvefabrication stabilityVSAvoidlayer structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by forming the support layer and adhesion layer before completing the device assembly. These layers are prepared in advance on the light emitting semiconductor layer, creating a pre-reinforced structure that prevents breakage during subsequent fabrication steps involving ohmic contact layer formation and reflection layer deposition

Inventive Principle:
Principle #10Preliminary action

3Reliability

If additional support layer and adhesion layer are added to improve adhesion, then fabrication stability improves, but the device structure becomes more complex

Engineering Contradiction:
Improvefabrication stabilityVSAvoidstructural complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The support layer and adhesion layer serve as intermediary elements that resolve the conflict between reliability and complexity. By inserting these specialized layers, the patent achieves fabrication stability without requiring fundamental redesign of the entire device structure, thus limiting the increase in overall structural complexity

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2228837B1Light emitting device, fabrication method thereof, and light emitting apparatus
Publication Date: 2019.06.19 LG INNOTEK CO LTD
  • EP2228837B1 patent drawingFigure 1~3
  • EP2228837B1 patent drawingFigure 4~6
  • EP2228837B1 patent drawingFigure 7~8

AI summary

A light emitting device is provided. The light emitting device comprises a conductive substrate (13), a reflection layer (11), a support layer (7), an ohmic contact layer (9), and a light emitting semiconductor layer (3,4,5). The reflection layer (11) is disposed on the conductive substrate (13). The support layer (7) is disposed partially on the reflection layer (11). The ohmic contact layer (9) is disposed at the side of the support layer (7). The light emitting semiconductor layer is disposed on the ohmic contact layer (9) and the support layer (7).