Sintered Phosphor Composite With Fluoride Binder for LED Heat Dissipation
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Solution Overview
Problem
Conventional wavelength conversion light-emitting layers using organic binders suffer from insufficient durability, heat resistance, and emission intensity, while inorganic binder-based layers face low thermal conductivity and poor heat dissipation, leading to decreased phosphor luminance.
Innovation Solution
A sintered phosphor-composite is developed using a nitride phosphor and a fluoride inorganic binder, where the nitride phosphor is dispersed in the fluoride binder, with a volume fraction of the binder being between 60% and 99%, and sintered at temperatures between 400°C and 1500°C, resulting in high internal quantum efficiency, heat resistance, and thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If organic binders are used in wavelength conversion light-emitting layers, then ease of manufacture is improved, but durability, heat resistance, and emission intensity deteriorate
Solution Approach 1:
The patent changes the fundamental parameter of the binder material from organic to inorganic (fluoride-based), which fundamentally alters the thermal stability, durability, and emission properties of the light-emitting layer, resolving the contradiction between ease of manufacture and reliability
Solution Approach 2:
The patent creates a composite structure combining fluoride inorganic binder with nitride phosphor particles, achieving both high durability/heat resistance and maintained emission intensity through the synergistic combination of materials with complementary properties
2Reliability
If inorganic binder-based layers are used, then durability and heat resistance are improved, but thermal conductivity and heat dissipation deteriorate
Solution Approach 1:
The patent selects fluoride-based inorganic binders (such as CaF2, SrF2, BaF2) which inherently possess higher thermal conductivity compared to traditional oxide-based inorganic binders, thus improving heat dissipation while maintaining the durability and heat resistance benefits of inorganic materials
3Reliability
If nitride phosphor is dispersed in fluoride inorganic binder, then internal quantum efficiency and thermal conductivity are improved, but manufacturing complexity increases
Solution Approach 1:
The patent optimizes the volume fraction of fluoride inorganic binder to 60-99% to achieve the desired balance between internal quantum efficiency, thermal conductivity, and manufacturing feasibility, demonstrating that parameter optimization can resolve the contradiction between performance improvement and manufacturing complexity
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 sintered phosphor-composite exhibits high luminance, high conversion efficacy, low brightness variation, and small color deviation due to variations in excitation light intensity and temperature, with improved thermal conductivity and transmittance.
Implementation Method 1
phosphor materials with excellent properties have been recently developed in multinary nitrides and oxynitrides based on silicon nitride, and have been used in wavelength conversion light-emitting layers. These phosphor materials are known to be excited to emit yellow or red light by blue LEDs or near ultraviolet LEDs
Implementation Method 2
a method for producing a sintered phosphor-composite... sintering the green body... a step of sintering, at a temperature of 400°C or more and 1500°C or less, the mixture obtained in the step
Data Source
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AI summary
Provided is a sintered phosphor-composite for an LED, having high heat resistance, high thermal conductivity, high luminance, and high conversion efficiency. In addition, there are provided: a light-emitting apparatus which uses the sintered phosphor-composite; and an illumination apparatus and a vehicular headlamp which use the light-emitting apparatus. The sintered phosphor-composite includes a nitride phosphor and a fluoride inorganic binder. The sintered phosphor-composite preferably has an internal quantum efficiency of 60% or more when excited by blue light having a wavelength of 450 nm. Further, the sintered phosphor-composite preferably has a transmittance of 20% or more at a wavelength of 700 nm.