Quantum Dot LED Cap Thermal Isolation

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Solution Overview

Problem

Current LED technologies face challenges in using quantum dots due to their air sensitivity, heat instability, and reduced light conversion efficiencies, particularly when integrated into LED devices, as they tend to agglomerate and are susceptible to photo-oxidation, leading to poor performance and compatibility issues with encapsulants.

Innovation Solution

Incorporating quantum dots into a cap that can be integrated with standard LED packages, where they are spaced apart from the LED chip to avoid heat and oxygen exposure, using a cap design that includes a matrix material like acrylate or epoxy to protect the QDs and enhance stability, and employing core-shell structures to improve quantum efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If quantum dots are integrated directly into LED encapsulants, then light conversion efficiency is improved, but heat instability and photo-oxidation susceptibility worsen

Engineering Contradiction:
Improvelight conversion efficiencyVSAvoidheat instability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The invention divides the LED structure into separate functional zones: the LED chip remains in its original encapsulant, while quantum dots are placed in a separate cap structure. This segmentation allows the QDs to be spatially separated from heat-generating components while maintaining optical coupling, thus preserving light conversion efficiency without exposing QDs to excessive heat

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary cap structure that acts as a buffer between the LED chip and quantum dots. This cap provides thermal isolation while allowing optical energy transfer, protecting the QDs from direct heat exposure and photo-oxidation while maintaining their light conversion function

Inventive Principle:
Principle #24Intermediary (Mediator)

2Use of energy by moving object

If quantum dots are placed close to LED chip, then light absorption is improved, but heat exposure and agglomeration worsen

Engineering Contradiction:
Improvelight absorptionVSAvoidheat exposure
Core Design Contradiction:
Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The invention transitions from a one-dimensional arrangement (QDs mixed in encapsulant near chip) to a three-dimensional configuration where QDs are positioned in a cap structure at a specific distance from the LED chip. This spatial arrangement optimizes both light absorption path length and thermal separation, allowing close proximity for optical coupling while maintaining distance for thermal protection

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

3Ease of manufacture

If quantum dots are exposed to air, then manufacturing is simplified, but photo-oxidation and stability worsen

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidphoto-oxidation resistance
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent employs an inert or oxygen-excluded environment within the LED package cavity where quantum dots are positioned. This creates a protective atmosphere that prevents photo-oxidation of the QDs while allowing them to maintain their photoluminescence properties, thus ensuring long-term stability without compromising manufacturing feasibility

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

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

This design enhances the shelf life and operational stability of quantum dots, reduces heat-related complications, and maintains high quantum efficiency, providing improved light output and color uniformity while being compatible with existing manufacturing processes.

Implementation Method 1

LED cap containing quantum dot phosphors... QD phosphor is held within the well of the LED package, so as to absorb the maximum amount of light emitted by the LED

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentEP3068845B1LED cap containing quantum dot phosphors
Publication Date: 2020.09.30 NANOCO TECH LTD
  • EP3068845B1 patent drawingFigure 1~2
  • EP3068845B1 patent drawingFigure 3A~3B
  • EP3068845B1 patent drawingFigure 4

AI summary

An LED device has a cap containing one or more quantum dot (QD) phosphors. The cap may be sized and configured to be integrated with standard LED packages. The QD phosphor may be held within the well of the LED package, so as to absorb the maximum amount of light emitted by the LED, but arranged in spaced-apart relation from the LED chip to avoid excessive heat that can lead to degradation of the QD phosphor(s). The packages may be manufactured and stored for subsequent assembly onto an LED device.