Light-emitting Device with Segmented Phosphors for Color Rendering
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Solution Overview
Problem
Conventional light-emitting devices employing LEDs often suffer from inadequate color rendering properties, particularly in the blue-green and red regions, and lack effectiveness in germ proliferation control.
Innovation Solution
A light-emitting device incorporating a light-emitting element with a peak emission wavelength of 400 nm to 410 nm, combined with four specific phosphors (Eu-activated alkaline-earth phosphate, Eu-activated halogen-containing alkaline-earth silicate, Ce-activated rare-earth aluminate, and Eu-activated silicon nitride) to enhance color rendering indices and germ alleviation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a combination of blue LED and yellow phosphor is used, then emission intensity and efficiency in the visible region are improved, but color rendering properties in the blue-green and red regions deteriorate
Solution Approach 1:
The patent segments the phosphor system into multiple distinct phosphor materials, each responsible for specific wavelength regions. Instead of using a single yellow phosphor, the invention employs a combination of phosphors including yellow-green phosphors (Y3Al5O12:Ce, Lu3Al5O12:Ce), red phosphors (CaAlSiN3:Eu, Sr2Si5N8:Eu), and green phosphors (β-SiAlON:Eu, SrSi2O2N2:Eu), where each phosphor segment targets specific gaps in the spectrum to improve overall color rendering while maintaining high emission intensity.
Solution Approach 2:
The patent creates a composite phosphor system by combining multiple phosphor materials with complementary emission characteristics. The composite structure includes phosphors with peak wavelengths spanning from yellow (560-580nm) to red (610-650nm), where each component material contributes specific spectral regions. This composite approach allows the system to achieve both high emission intensity and improved color rendering properties across the visible spectrum, particularly in the previously deficient blue-green and red regions.
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 achieves improved color rendering properties and effective germ proliferation control with reduced human body impact, offering safer and more efficient light emission compared to ultraviolet-based solutions.
Implementation Method 1
a light-emitting element with a peak emission wavelength in a range of 400 nm to 410 nm
Implementation Method 2
a fluorescent member that contains a first phosphor with a peak emission wavelength in a range of 440 nm to 470 nm
Data Source
AI summary
A light-emitting device includes a light-emitting element with a peak emission wavelength in a range of 400 nm to 410 nm and a fluorescent member that contains a first phosphor with a peak emission wavelength in a range of 440 nm to 470 nm containing a Eu-activated alkaline-earth phosphate that contains Cl in a composition, a second phosphor with a peak emission wavelength in a range of 500 nm to 530 nm containing a Eu-activated halogen-containing alkaline-earth silicate, a third phosphor with a peak emission wavelength in a range of 530 nm to 600 nm containing a Ce-activated rare-earth aluminate, and a fourth phosphor with a peak emission wavelength in a range of 600 nm to 660 nm containing a Eu-activated silicon nitride containing Al and at least one of Sr and Ca in a composition.