Red Light Emitting Device with CaSrEuSiAlN Phosphor
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Solution Overview
Problem
There is a need for a red light-emitting light emitting device that achieves high luminous flux and color purity, which existing technologies have not adequately addressed.
Innovation Solution
A light emitting device comprising a light emitting element with a peak emission wavelength in the range of 400 nm to 500 nm and a fluorescent member containing a fluorescent material with a peak emission wavelength in the range of 630 nm to 670 nm, specifically formulated to achieve CIE 1931 chromaticity coordinates of 0.640 or more, utilizing a composition represented by formula (I) and a specific arrangement of the fluorescent material to enhance emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a light emitting element with peak emission wavelength of 400-500 nm and a fluorescent material with peak emission wavelength of 630-670 nm are used, then color purity (x value of CIE 1931 chromaticity coordinates) is improved to 0.640 or more, but luminous flux is insufficient
Solution Approach 1:
The patent optimizes the composition parameters of the fluorescent material by precisely controlling the ratios of Ca, Sr, Eu, Si, and Al atoms in the chemical formula Ca_sSr_tEuuSivAlwNx, and by optimizing the peak emission wavelength to 630-670 nm, thereby achieving high color purity (x≥0.640) while maintaining high luminous flux
Solution Approach 2:
The patent uses a composite fluorescent material containing multiple elements (Ca, Sr, Eu, Si, Al, N, x) with specific compositional ratios, combining the advantages of different elements to achieve both high color purity and high luminous flux that cannot be achieved with single-element fluorescent materials
2Device complexity
If existing fluorescent materials are used to achieve red light emission, then device complexity is reduced, but emission efficiency is insufficient
Solution Approach 1:
The patent optimizes the compositional parameters (s, t, u, v, w, x in the formula Ca_sSr_tEuuSivAlwNx) and the peak emission wavelength (630-670 nm) of the fluorescent material to maximize emission efficiency while maintaining simple device structure
Solution Approach 2:
The patent achieves high emission efficiency by precisely controlling the peak emission wavelength of the fluorescent material to be in the range of 630-670 nm, which optimizes the wavelength conversion from the blue light emitting element to red light, thereby improving overall emission efficiency without increasing device complexity
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 device emits red light with high luminous flux and color purity, achieving improved emission efficiency and reduced scattering loss through the precise formulation and arrangement of the fluorescent material, resulting in enhanced chromaticity coordinates and increased productivity.
Implementation Method 1
a fluorescent member containing a fluorescent material having a peak emission wavelength in a range of 630 nm to 670 nm
Implementation Method 2
a fluorescent material that absorbs light from the light emitting element and performs wavelength conversion to emit red light
Data Source
AI summary
Provided is a light emitting device which includes a light emitting element having a peak emission wavelength in a range of 400 nm to 500 nm, and a fluorescent member containing a fluorescent material having a peak emission wavelength in a range of 630 nm to 670 nm, and a composition represented by the formula. CasSrtEuuSivAlwNx. In the formula, s, t, u, v, w, and x satisfy 0.25≤s≤0.5, 0.4≤t≤0.75, 0.01≤u≤0.04, 0.8≤s+t+u≤1.1, 0.8≤v≤1.2, 0.8≤w≤1.2, 1.8≤v+w≤2.2, and 2.5≤x≤3.2. The light emitting device emits light having an x value of CIE 1931 chromaticity coordinates of 0.640 or more.