Color Conversion Layer Refractive Index Optimization
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Solution Overview
Problem
Conventional color conversion layers in display devices, particularly those using quantum dots, suffer from inefficiencies due to exposure to oxygen, high temperatures, and UV rays, leading to deterioration of optical properties and requiring increased thickness, concentration of quantum dots, or primary light intensity to compensate.
Innovation Solution
A color conversion layer comprising nanoparticles encapsulated in an inorganic material with a refractive index difference greater than 0.02 from the surrounding medium, which limits molecular diffusion and oxidation, allowing for lower particle concentrations and improved light emission efficiency while maintaining equivalent thickness and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If quantum dot composite is used in a resin matrix, then the color conversion layer can be manufactured, but the quantum dots are exposed to oxygen, high temperature and UV-ray leading to deterioration of optical properties
Solution Approach 1:
The patent applies nested protection by placing quantum dots inside a core shell structure (core quantum dot nested within protective shell), then embedding these composite particles within a polymer matrix. This multi-level nesting provides progressive protection: the shell protects quantum dots from oxidation during processing, while the polymer matrix provides additional environmental protection, resolving the contradiction between manufacturability and optical stability.
Solution Approach 2:
The patent uses composite materials at multiple levels: (1) core-shell composite structure where a shell material is deposited on quantum dots to protect them from oxidation, (2) composite particles combining quantum dots with scattering particles, and (3) final composite layer of polymer matrix containing protected quantum dots. These composite structures enable both easy manufacturing and protection against deterioration.
2Productivity
If the thickness of color conversion layer or concentration of quantum dots is increased to compensate for low efficiency, then light conversion can be improved, but the device complexity and material usage increase
Solution Approach 1:
The patent changes key parameters to improve efficiency: (1) introduces shell material on quantum dots to protect against oxidation and maintain optical properties, (2) uses composite particles combining quantum dots with scattering particles to enhance light interaction, and (3) selects polymer matrices with specific optical properties (refractive index, transparency). These parameter changes enable high conversion efficiency without increasing thickness or concentration.
Solution Approach 2:
The patent introduces intermediary elements: (1) shell material acts as intermediary between quantum dots and environment, protecting them while allowing optical function, (2) scattering particles act as intermediaries to enhance light interaction with quantum dots, and (3) polymer matrix serves as intermediary medium that protects and positions quantum dots. These intermediaries enable efficient light conversion without requiring increased thickness or concentration.
3Ease of manufacture
If conventional quantum dot composite is used, then the color conversion layer can be formed, but protection against oxidation by oxygen and humidity from ambient atmosphere is insufficient
Solution Approach 1:
The patent applies nested protection by placing quantum dots inside a core shell structure (core quantum dot nested within protective shell), then embedding these composite particles within a polymer matrix. This multi-level nesting provides progressive protection: the shell protects quantum dots from oxidation during processing, while the polymer matrix provides additional environmental protection, resolving the contradiction between manufacturability and optical stability.
Solution Approach 2:
The patent introduces intermediary elements: (1) shell material acts as intermediary between quantum dots and environment, protecting them while allowing optical function, (2) scattering particles act as intermediaries to enhance light interaction with quantum dots, and (3) polymer matrix serves as intermediary medium that protects and positions quantum dots. These intermediaries enable efficient light conversion without requiring increased thickness or concentration.
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 solution enhances light conversion efficiency, protects nanoparticles from oxidation, and reduces material costs by decreasing the required concentration of particles, while maintaining optical performance and resistance to environmental factors.
Implementation Method 1
the inorganic material limits or prevents the diffusion of outer molecular species or fluids (liquid or gas) into said inorganic material
Implementation Method 2
The scattering particles are able to scatter the incident light in all directions and also towards the quantum dot composite
Implementation Method 3
The quantum dot composite, when excited by a primary light, emits a secondary light at a different wavelength than the incident light
Implementation Method 4
said inorganic material has a difference of refractive index compared to the at least one surrounding medium superior or equal to 0.02 at 450 nm
Data Source
AI summary
Disclosed is a color conversion layer including at least one light emitting material including at least one composite particle surrounded partially or totally by at least one surrounding medium; wherein the light emitting material is configured to emit light in response to an excitation and the at least one composite particle includes a plurality of nanoparticles encapsulated in an inorganic material; and wherein the inorganic material has a difference of refractive index compared to the at least one surrounding medium superior or equal to 0.02 at 450 nm. Also disclosed is a display apparatus.