Light-Emitting Device Phosphor Gradient and Scattering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing light-emitting devices exhibit high emission angle dependency of light chromaticity due to minimal scattering by phosphor particles, leading to uneven chromaticity, and lack efficient light conversion.
Innovation Solution
A light-emitting device with phosphor particles of average size ≤20 nm, dispersed light-scattering particles with larger size and refractive index, and a three-dimensional network structure, featuring a concentration gradient of phosphor particles to enhance light conversion efficiency and reduce emission angle dependency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If phosphor particles with average size ≤20 nm are used, then light conversion efficiency is improved, but emission angle dependency of chromaticity increases
Solution Approach 1:
The patent applies local quality by creating a concentration gradient of phosphor particles in the sealing material, with higher concentration near the light-emitting element and lower concentration toward the emission surface. This localized distribution optimizes light conversion efficiency near the source while reducing chromaticity variation at different emission angles, resolving the contradiction between conversion efficiency and chromaticity uniformity.
Solution Approach 2:
The patent uses a composite sealing material containing phosphor particles dispersed in a transparent resin matrix. This composite structure allows the phosphor particles to convert light efficiently while the resin matrix provides optical transparency and structural support, enabling both high light conversion efficiency and controlled emission characteristics.
2Loss of energy
If phosphor particles are dispersed uniformly in sealing material, then light conversion is efficient, but chromaticity unevenness increases due to direct light emission
Solution Approach 1:
The patent implements local quality through a non-uniform concentration distribution of phosphor particles, with maximum concentration near the light-emitting element and decreasing concentration toward the emission surface. This gradient structure ensures efficient light conversion near the source while reducing direct light emission effects at the emission surface, achieving both high conversion efficiency and uniform chromaticity.
3Ease of manufacture
If light-scattering particles are added to scatter light, then emission angle dependency is reduced, but device complexity increases
Solution Approach 1:
The patent merges the functions of phosphor particles and light-scattering particles into a single sealing material composition. The phosphor particles serve dual purposes: light conversion and light scattering. This integration achieves reduced emission angle dependency without requiring separate light-scattering components, thereby reducing device complexity while maintaining chromaticity uniformity.
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 effectively lowers emission angle dependency of light chromaticity and increases light conversion efficiency by scattering light with larger light-scattering particles while maintaining high phosphor concentration near the light-emitting element.
Implementation Method 1
phosphor particles formed into nanoparticles are dispersed in a sealing material which seals a light-emitting element
Implementation Method 2
light emitted from the light-emitting element is little scattered by the phosphor particles
Implementation Method 3
light-scattering particles as well as phosphor particles formed into nanoparticles are dispersed in the sealing material... light emitted from the light-emitting element can be scattered by the light-scattering particles
Implementation Method 4
a dispersed particle dispersed in the sealing material and forming a three-dimensional network structure in the sealing material
Data Source
AI summary
A light-emitting device includes a light-emitting element, a sealing material for sealing the light-emitting element, a phosphor particle having an average particle size of not more than 20 nm and dispersed in the sealing material, a dispersed particle dispersed in the sealing material and forming a three-dimensional network structure in the sealing material, and a light-scattering particle dispersed in the sealing material, having an average particle size greater than that of the phosphor particle and that of the dispersed particle, and having a refractive index greater than that of the sealing material. A concentration gradient of the phosphor particle in a height direction is formed such that a concentration thereof increases according as a position thereof decreases. An average position of the phosphor particle is lower than that of the light-scattering particle.