Red Phosphor Material High-Temperature Luminance Retention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional red phosphor materials exhibit poor temperature characteristics, leading to low luminance retention ratios at high temperatures, causing variations in brightness and color tone in high-emission light-emitting devices.
Innovation Solution
A red phosphor material with a composition formula of ALn1-x-yEuxSmyM2O8, where A represents Li, Na, or K, Ln represents La or Gd, and M represents W or Mo, with x and y values between 0.1 and 0.7, and 0.005 and 0.08, respectively, which allows for high luminance retention at elevated temperatures and excitation with readily available light sources like LEDs or lasers at 405 nm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional red phosphor materials are used, then light-emitting efficiency can be maintained, but luminance retention ratio at high temperature deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the compositional parameters (x and y values) of the phosphor material ALn1-x-yEuxSmyM2O8. By optimizing the substitution ratios of Eu and Sm ions along with sintering temperature and atmosphere parameters, the invention achieves both high light-emitting efficiency and excellent high-temperature stability, resolving the contradiction between efficiency and reliability.
Solution Approach 2:
The patent uses composite material principles by creating a multi-element phosphor system combining ALn1-x-yEuxSmyM2O8 with specific ratios of rare earth elements (Eu, Sm) and metal elements (W, Mo). This composite structure leverages the complementary properties of different elements: Eu provides red emission while Sm enhances thermal stability, achieving both high efficiency and reliable luminance retention at elevated temperatures.
2Use of energy by moving object
If amount of phosphor substance is increased to compensate for low light-emitting efficiency, then efficiency can be improved, but device complexity increases
Solution Approach 1:
Instead of increasing the amount of phosphor material, the invention improves light-emitting efficiency by changing the compositional parameters of the phosphor itself. By optimizing the Eu/Sm ratio and sintering conditions, the patent achieves high efficiency with a standard amount of phosphor, avoiding the need for increased material quantity and the associated device complexity.
3Adaptability or versatility
If red phosphor material is excited with 405 nm light source, then adaptability to available excitation sources is improved, but excitation efficiency may deteriorate
Solution Approach 1:
The patent optimizes the compositional parameters of the phosphor material to achieve dual benefits: the specific ratio of Eu and Sm substitution along with appropriate sintering parameters creates absorption characteristics that are well-matched to 405 nm excitation light, ensuring both high adaptability to available LED/laser sources and efficient energy conversion to red emission.
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 red phosphor material maintains an 80% or higher luminance retention ratio from 30°C to 200°C, ensuring consistent brightness and color tone even under high-temperature conditions, and can be effectively excited with 405 nm light, enhancing its practical application in high-power light-emitting devices.
Implementation Method 1
a phosphor substance that partially absorbs blue light emitted by the LED chip and emits yellow light
Data Source
AI summary
A red phosphor material comprising an essential component represented by a formula of ALn1-x-yEuxSmyM2O8 as a main component, where A represents at least one selected from Li, Na, and K; Ln represents at least one selected from La and Gd; M represents at least one selected from W and Mo; and x and y are numerical values that satisfy 0.1≦x+y≦0.7 and 0.005≦y≦0.08. A light-emitting device includes an excitation light source and the red phosphor material that absorbs excitation light emitted by the excitation light source and emits red light.