Single Crystal Phosphor Plate for High-Power LED Thermal Stability

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Solution Overview

Problem

High-powered light emitting devices face issues with heat generation and variations in light emission characteristics due to temperature increases, affecting both the light emitting element and phosphor properties.

Innovation Solution

A plate-shaped transparent member composed of granular-shaped single crystal phosphors with excellent quantum efficiency and temperature quenching characteristics, manufactured using methods like the Czochralski Method, is used in light emitting devices to minimize emission spectrum variation and maintain brightness across a wider temperature range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If high-powered light emitting devices are used to increase brightness and output, then light emission intensity is improved, but heat generation increases causing temperature rise

Engineering Contradiction:
Improvelight emission intensityVSAvoidtemperature
Core Design Contradiction:
Illumination intensityVSTemperature

Solution Approach 1:

The patent changes the material parameter from conventional phosphor to single crystal phosphor, which fundamentally alters the temperature quenching characteristics and maintains quantum efficiency across a wider temperature range, resolving the contradiction between high output and heat management

Inventive Principle:
Principle #35Parameter changes

2Illumination intensity

If conventional phosphor is used in high-powered devices, then initial brightness is achieved, but quantum efficiency decreases due to temperature quenching

Engineering Contradiction:
ImprovebrightnessVSAvoidquantum efficiency
Core Design Contradiction:
Illumination intensityVSLoss of energy

Solution Approach 1:

The patent changes the phosphor material parameter to single crystal structure, which fundamentally improves temperature quenching characteristics and maintains quantum efficiency at high temperatures, resolving the contradiction between brightness and energy efficiency

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If standard phosphor materials are used, then device simplicity is maintained, but emission spectrum varies significantly with temperature

Engineering Contradiction:
Improvedevice simplicityVSAvoidemission spectrum stability
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The patent changes the phosphor material parameter to single crystal structure, which fundamentally stabilizes the emission spectrum across temperature variations while maintaining device simplicity, resolving the contradiction between simplicity and spectral stability

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

The solution provides light emitting devices with higher brightness, reduced temperature-dependent fluorescence intensity loss, and smaller characteristics variations, enabling higher output and longer lifespan.

Implementation Method 1

a phosphor configured to emit a fluorescent light by receiving an excitation light so as to be excited

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Implementation Method 2

manufactured using methods like the Czochralski Method

Methodology Applied
Scientific EffectCrystallisation: Crystallisation

Data Source

PatentEP3470495B1Transparent member and light-emitting device
Publication Date: 2022.08.24 NAT INST FOR MATERIALS SCI
  • EP3470495B1 patent drawingFigure 1
  • EP3470495B1 patent drawingFigure 2
  • EP3470495B1 patent drawingFigure 3

AI summary

One purpose of the invention is to provide a phosphor with excellent quantum efficiency, a method for manufacturing the same, and a light-emitting device that uses this phosphor. One embodiment provides a phosphor comprising monocrystals with YAG crystals as a matrix, the quantum efficiency of the phosphor at 25°C being 92% or higher at an excitation light wavelength of 460 nm.