Narrow-Band Phosphor Composition for Blue LED Light Conversion

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Solution Overview

Problem

Existing phosphors used in LED lighting exhibit low emission intensity, broad spectral half peak width, and environmental hazards, necessitating a phosphor with improved emission characteristics and conversion efficiency for better color rendering and reproducibility.

Innovation Solution

A phosphor with a specific crystal phase composition, represented by formulas Re x MA a MB b MC c N d X e and Re x MA a MB b (MC' 1-y MD y ) c N d X e, with controlled reflectance and emission peak wavelengths, is developed to enhance emission intensity and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a blue light-emitting solid-state lighting device is used, then the device has a long lifetime and high durability, but the blue light causes harmful effects on human eyes and suppresses melatonin secretion

Engineering Contradiction:
Improvedevice lifetimeVSAvoidharmful effects on human eyes
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent segments the blue light emission into multiple wavelength components by using a blue LED combined with multiple phosphors (yellow phosphor, orange phosphor, and red phosphor) that emit at different wavelengths. This segmentation allows the harmful blue light to be distributed and reduced across multiple lower-energy wavelengths, thereby reducing eye strain and melatonin suppression while maintaining the long lifetime advantage of LED technology.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces phosphors as intermediary materials between the blue LED light source and the human eye. These phosphors absorb the harmful blue light and re-emit it as less harmful wavelengths (yellow, orange, and red light). The phosphors act as mediators that convert the harmful blue radiation into beneficial visible light, preserving the LED's durability while eliminating its harmful effects.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the light source is changed to reduce harmful effects, then the harmful effects are reduced, but the device complexity increases

Engineering Contradiction:
Improveharmful effects on human eyesVSAvoiddevice structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges multiple phosphor materials (yellow phosphor, orange phosphor, and red phosphor) into a single integrated lighting device structure. Instead of using separate light sources for different wavelengths, all phosphors are combined and excited by a single blue LED, achieving full-spectrum light output with reduced harmful effects while maintaining simple device architecture and avoiding the complexity of multiple independent light sources.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The blue LED serves multiple functions simultaneously: it provides the primary light source and acts as the excitation source for all three phosphor materials. This multi-functionality eliminates the need for separate excitation sources for each phosphor type, thereby reducing device complexity while achieving the goal of reducing harmful blue light effects through comprehensive phosphor conversion.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Object-affected harmful factors

If multiple phosphors are used to reduce blue light effects, then the harmful effects are reduced, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveharmful effects on human eyesVSAvoidphosphor particle size control
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent specifies precise particle size ranges for each phosphor type (yellow phosphor: 1-10 μm, orange phosphor: 1-10 μm, red phosphor: 1-10 μm) to optimize light conversion efficiency and minimize harmful blue light transmission. By controlling the particle size parameter within these specific ranges, the patent achieves effective blue light reduction while providing clear manufacturing guidelines that balance precision requirements with practical manufacturability.

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 new phosphor provides improved color rendering, color reproducibility, and conversion efficiency in LED devices, addressing the limitations of existing phosphors.

Implementation Method 1

a blue light source and yellow, orange, and red phosphors which emit yellow, orange, and red light, respectively, when excited by blue light

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentEP4293732B1Phosphor, light-emitting device, lighting device, image display device, and indicator lamp for vehicles
Publication Date: 2026.04.29 MITSUBISHI CHEM CORP
  • EP4293732B1 patent drawingFigure 1~2
  • EP4293732B1 patent drawingFigure 3
  • EP4293732B1 patent drawingFigure 4A~4B

AI summary

Provided is a phosphor that has a favorable emission peak wavelength, a narrow spectral half width, and high light emission intensity. Also provided are: a light-emitting device that has favorable color rendering properties or color reproducibility, as well as favorable conversion efficiency; a lighting device; an image display device; and an indicator lamp for vehicles. The present invention pertains to: a phosphor comprising a crystalline phase that has a composition represented by a specific formula, and a minimum value of reflectance in a predetermined wavelength range at 20% or greater, the predetermined wavelength range being the range from an emission peak wavelength to 800 nm; and a light-emitting device provided with said phosphor.