Phosphor Composition for Warm Light Emission

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Solution Overview

Problem

Conventional white light-emitting devices using LEDs or laser diodes have a higher color temperature than traditional incandescent or fluorescent lamps, making them less suitable for indoor lighting due to their cooler, bluer light emission.

Innovation Solution

A phosphor with the formula (M2x,M3y,M4z)mM1O3X(2/n) is used in combination with a blue phosphor, where M1 includes Si, Ge, Ti, or Sn, M2 includes Ca, Mg, Cd, or Zn, M3 includes Sr, Ra, or Ba, X is a halogen, and M4 includes Eu2+ or Mn, to produce a warm light-emitting device with a color temperature of 3200 K or less, utilizing a semiconductor light-emitting element that emits ultraviolet or short-wavelength visible light.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If conventional white light-emitting devices use LEDs or laser diodes with phosphors, then energy efficiency and lifespan are improved, but color temperature becomes too high for comfortable indoor lighting

Engineering Contradiction:
Improvepower consumptionVSAvoidcolor temperature
Core Design Contradiction:
Use of energy by moving objectVSTemperature

Solution Approach 1:

The patent changes the chemical composition parameters of the phosphor material by incorporating specific ratios of Ca, Sr, Ba, and Eu elements to adjust the emission spectrum. By modifying the phosphor's chemical formula (Ca1-x-y-zEuxSr1-yMg1-z)2Si2O2N2, the color temperature is tuned to 2856K or 6504K to match standard lighting conditions while maintaining LED energy efficiency

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses composite phosphor materials combining multiple elements (Ca, Sr, Ba, Mg, Eu) in specific ratios to achieve the desired color temperature. The composite structure allows simultaneous optimization of luminous efficiency and color rendering, resolving the contradiction between energy efficiency and appropriate color temperature

Inventive Principle:
Principle #40Composite materials

2Use of energy by moving object

If phosphors are used to convert ultraviolet or short-wavelength visible light to longer wavelengths, then energy efficiency is improved, but the color rendering and warmth of light deteriorate

Engineering Contradiction:
Improveenergy efficiencyVSAvoidcolor rendering quality
Core Design Contradiction:
Use of energy by moving objectVSIllumination intensity

Solution Approach 1:

The patent optimizes the phosphor composition parameters (x, y, z values representing Eu, Sr, and Mg content respectively) to control the emission spectrum shape. By adjusting these parameters, the phosphor converts UV/blue light while maintaining excellent color rendering properties and producing warm, natural light appearance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces traditional incandescent heating-based light generation with phosphor-converted LED technology, substituting thermal conversion with photoluminescence conversion. This achieves both high energy efficiency and superior color rendering by using quantum mechanical photon conversion rather than thermal radiation

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 enables the production of light-emitting devices that emit warm, incandescent-like light with a color temperature of 2800 K to 3200 K, providing high illuminance and low power consumption, suitable for various lighting applications with improved color rendering compared to conventional devices.

Implementation Method 1

a first phosphor which is excited by the ultraviolet light or the short-wavelength visible light to emit visible light

Methodology Applied
Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentUS9337399B2Phosphor and light-emitting device
Publication Date: 2016.05.10 KOITO MFG CO LTD

AI summary

A phosphor has the general formula (M2x,M3y,M4z)mM1O3X(2/n), wherein M1 represents at least one element including at least Si and selected from the group consisting of Si, Ge, Ti, Zr, and Sn, M2 represents at least one element including at least Ca and selected from the group consisting of Ca, Mg, Cd, Co, and Zn, M3 represents at least one element including at least Sr and selected from the group consisting of Sr, Ra, Ba, and Pb, X represents at least one halogen element, M4 represents at least one element including at least Eu2+ and selected from the group consisting of rare-earth elements and Mn, m is in the range 1≦m≦4/3, n is in the range 5≦n≦7, and x, y, and z are each in such a range as to satisfy x+y+z=1, 0.45≦x≦0.8, 0.05≦y≦0.45, and 0.45, and 0.03≦z≦0.35.