Quantum Dot Wavelength Conversion Layers With Low-Moisture Barriers

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Solution Overview

Problem

Conventional wavelength converting members experience changes in light emission intensity over time due to environmental factors, particularly high moisture vapor transmission rates through barrier layers, leading to deterioration of quantum dots.

Innovation Solution

The implementation of barrier layers with a moisture vapor transmission rate of less than 9 g/(m²·d), preferably 0.1 g/(m²·d or less, to protect quantum dots from environmental degradation, using a layered structure of organic and inorganic materials with improved adhesion and barrier properties, and applying these layers on both sides of the quantum dot layer to inhibit light emission intensity changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If barrier layers are added to protect quantum dots from environmental conditions, then photostability is improved, but moisture vapor transmission rate increases causing quantum dot deterioration

Engineering Contradiction:
ImprovephotostabilityVSAvoidmoisture vapor transmission rate
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The barrier layer is constructed as a composite material comprising an inorganic layer (such as aluminum oxide, silicon oxide, or titanium oxide) and an organic layer (such as polyethylene terephthalate or cyclic olefin copolymer). This composite structure combines the low moisture vapor transmission properties of inorganic materials with the flexibility and processability of organic materials, achieving both protection against moisture and structural integrity.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The barrier layer is divided into multiple sub-layers: an inorganic layer providing the primary moisture barrier function, and an organic layer providing structural support and flexibility. This segmentation allows each layer to perform its specialized function optimally - the inorganic layer blocks moisture vapor while the organic layer provides mechanical strength.

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If conventional barrier layers are used, then quantum dots are protected from moisture, but light emission intensity changes over time

Engineering Contradiction:
Improveprotection from moistureVSAvoidlight emission intensity
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The invention specifies precise parameter ranges for the barrier layer materials, including moisture vapor transmission rate (less than 9 g/(m²·d)), layer thickness (5 μm to 200 μm), and material composition ratios. By controlling these parameters, the barrier layer achieves optimal balance between moisture protection and light transmission properties, preventing quantum dot deterioration while maintaining stable light emission intensity over time.

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

This approach effectively stabilizes light emission intensity over time, reducing quantum dot deterioration and maintaining consistent wavelength conversion characteristics in wavelength converting members.

Implementation Method 1

barrier layers with a moisture vapor transmission rate of less than 9 g/(m²·d)

Methodology Applied
Scientific EffectMoisture vapor transmission barrier: Permeation

Data Source

PatentEP3667746B1Method for manufacturing a wavelength conversion member
Publication Date: 2023.12.06 TOPPAN INC
  • EP3667746B1 patent drawingFigure 1A~1C
  • EP3667746B1 patent drawingFigure 2~3
  • EP3667746B1 patent drawingFigure 4A~7

AI summary

Provided is a wavelength converting member which can reduce change in the light emission intensity over time as compared with conventional members and a method of producing the wavelength converting member. A wavelength converting member (1) includes a quantum dot layer (2) having quantum dots, barrier layers (3, 4) formed on at least both sides of the quantum dot layer (2). The moisture vapor transmission rate of the barrier layer is lower than 9 g/(m2·d). Thus, change in the light emission intensity over time can be effectively inhibited.