Wavelength Converting Element Using Low Oxygen Diffusion Polymer

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Solution Overview

Problem

Organic phosphor materials in LED lighting systems suffer from poor photo-chemical stability, limiting their application due to sensitivity to heat and oxygen, which leads to rapid degradation and reduced lifetime.

Innovation Solution

A light-emitting device with a wavelength converting element using a polymeric carrier material with an oxygen diffusion coefficient of 8 x 10^-13 cm^2/s or less at 25°C, such as polyethylene terephthalate (PET) or its copolymers, which maintains stability and reduces degradation, allowing for improved organic phosphor performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If organic phosphor materials are used in LED lighting systems, then the luminescence spectrum can be easily adjusted and transparency is improved, but photo-chemical stability deteriorates due to sensitivity to heat and oxygen

Engineering Contradiction:
Improveluminescence spectrum adjustmentVSAvoidphoto-chemical stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces a polymeric carrier material as an intermediary between the organic phosphor and the external environment (oxygen and heat). This carrier material protects the phosphor from direct exposure to harmful factors while maintaining the phosphor's optical properties and spectrum adjustment capabilities.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates an inert environment by encapsulating the organic phosphor within a polymeric carrier material that has low oxygen permeability. This effectively isolates the phosphor from oxygen and reduces the impact of heat, providing protection without requiring complete vacuum or inert gas filling.

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

2Temperature

If organic phosphor materials are used in remote configuration devices, then heat sensitivity is reduced, but lifetime is limited due to poor photo-chemical stability

Engineering Contradiction:
Improveheat exposureVSAvoidlifetime
Core Design Contradiction:
TemperatureVSDuration of action of stationary object

Solution Approach 1:

The polymeric carrier material serves as a protective intermediary that further isolates the organic phosphor from environmental factors. Even in remote configuration where heat exposure is reduced, the carrier material provides additional protection against oxygen and residual heat, thereby extending the phosphor's lifetime.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent uses a composite structure consisting of the polymeric carrier material and the organic phosphor material. This composite provides both mechanical protection and chemical isolation, creating a stable environment that preserves the phosphor's properties over extended periods.

Inventive Principle:
Principle #40Composite materials

3Reliability

If inorganic phosphor materials are used, then quantum efficiency is limited and emission spectrum is broad, but photo-chemical stability is improved

Engineering Contradiction:
Improvephoto-chemical stabilityVSAvoidefficiency loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent employs organic phosphor materials that, while having shorter inherent lifetimes compared to inorganic phosphors, can be protected and extended in life through the polymeric carrier material. This approach allows utilization of the superior optical properties of organic phosphors with improved durability.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the physical and chemical parameters of the phosphor environment by embedding it in a polymeric matrix with specific oxygen permeability characteristics. This parameter change protects the phosphor's optical properties while extending its operational life, achieving both high efficiency and improved stability.

Inventive Principle:
Principle #35Parameter changes

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 use of a polymeric carrier material with a low oxygen diffusion coefficient enhances the stability and lifetime of organic phosphor materials, achieving performance comparable to an inert atmosphere without the need for complete inert conditions, thereby improving the efficiency and longevity of LED lighting systems.

Implementation Method 1

a first organic wavelength converting material adapted to convert light of a first wavelength to light of a second wavelength

Methodology Applied
Scientific EffectWavelength conversion: Fluorescence

Implementation Method 2

the oxygen diffusion coefficient (D) of the polymeric carrier material is 8 x 10^-13 cm^2/s or less at 25°C

Methodology Applied
Scientific EffectDiffusion barrier: Diffusion

Data Source

PatentEP2732006B1Wavelength converting element
Publication Date: 2018.09.12 SIGNIFY HOLDING BV
  • EP2732006B1 patent drawingFigure 1a~1b
  • EP2732006B1 patent drawingFigure 1c~1d
  • EP2732006B1 patent drawingFigure 2~3

AI summary

A wavelength converting element (101, 102, 103, 110) comprising a polymeric carrier material comprising a first wavelength converting material adapted to convert light of a first wavelength to light of a second wavelength, wherein the oxygen diffusion coefficient (D) of the polymeric carrier material is 8 x 10-13 cm2/s or less at 25°C. A prolonged lifetime of the wavelength converting material is achieved by selecting a polymeric carrier material with an oxygen diffusion coefficient (D) at 8x10-13 cm2/s or less at 25°C.