Nitridophosphate Red Phosphor Composition for White LED Color Rendering

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Solution Overview

Problem

There is a need for luminescent materials that efficiently absorb near-UV or blue light and emit red light, while also providing high luminous efficiency and acceptable color rendition quality.

Innovation Solution

A nitridophosphate material with a general formula AEy-xLi10-2yP4N10:Eux is developed, where AE includes Ca, Sr, or Ba, and y≥x>0, which exhibits a peak emission wavelength greater than 600 nm, offering improved spectral power distribution and color rendering index.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If conventional phosphors are used to convert blue light to red light, then the LED can emit red light, but the luminous efficiency is insufficient and color rendition quality is poor

Engineering Contradiction:

Improveluminous efficiencyVSAvoidcolor rendition quality

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The patent modifies the chemical composition parameters of the phosphor material by incorporating specific ratios of Ca, Sr, and Ba elements along with Eu activator, and adjusts the sintering temperature parameter to 900-1000°C to optimize the phosphor's emission characteristics and achieve both high luminous efficiency and good color rendition

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite phosphor material combining multiple alkaline earth metals (Ca, Sr, Ba) with phosphorus, nitrogen, and europium activator in a nitridophosphate structure, which synergistically improves both luminous efficiency and color rendition properties that cannot be achieved by single-element phosphors

Inventive Principle:

Principle #40Composite materials

2Reliability

If phosphor concentration is increased to improve color rendering, then color quality improves, but the amount of phosphor material required increases

Engineering Contradiction:

Improvecolor rendering indexVSAvoidphosphor material amount

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent optimizes the Eu activator concentration parameter within the range of 0.5-5 mol% to achieve maximum color rendering index without requiring excessive phosphor material, and adjusts the Ca:Sr:Ba ratio parameter to enhance emission intensity per unit volume

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 nitridophosphate luminescent material achieves increased luminous efficacy of radiation and improved light quality, measured by the average color rendering index Ra8, while reducing deep-red-light content.

Implementation Method 1

Phosphors that absorb light emitted by the LED and in response emit light of a longer wavelength

Methodology Applied

Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentUS20250197722A1Red-emitting nitridophosphate phosphor and white phosphor-converted LED

Publication Date: 2025.06.19 LUMILEDS LLC

AI summary

An inventive luminescent material suitable for use as a phosphor for an LED includes a nitridophosphate material having a general formula AEy-xLi10-2yP4N10:Eux, wherein (i) AE includes one or more of Ca, Sr, or Ba, and (ii) y≥x>0. In some instances, y can equal 2 and x can be between 0 and 0.1. In some instances, AE can include only Ca; in some other instances, AE can include a majority amount of Ca and lesser amounts of Sr or Ba. In some instances, the luminescent material can exhibit a peak emission wavelength greater than 600 nm.