LED Phosphor Segmentation for High Color Rendering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional white-light emitting devices using blue LEDs and yellow phosphors struggle to achieve high color rendering due to quantum deficits and efficiency losses, lacking green and red components, which limits their ability to express natural colors and increases costs with the use of expensive red phosphors.
Innovation Solution
A light emitting device utilizing a blue LED combined with three kinds of phosphors: (Ba x , Sr 1-x )Si 2 O 2 :Eu, (Lu x , Gd 1-x ) 3 Al 5 O 12 :Ce, and (Ca x , Sr 1-x )AlSiN 3 :Eu, which emit light in specific wavelength ranges to enhance color rendering without relying on expensive red phosphors, achieving a high color rendering index of 90 or higher.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a typical white-light emitting device combines blue LED and yellow phosphor to achieve easy operation and low cost, then ease of manufacture and cost are improved, but color rendering is poor and natural colors cannot be expressed
Solution Approach 1:
The patent segments the yellow phosphor into three distinct phosphors with specific wavelength ranges: first phosphor (495-510nm green-blue), second phosphor (550-555nm green), and third phosphor (580-605nm yellow-orange). This segmentation allows each phosphor to contribute specific color components, improving overall color rendering while maintaining manufacturing simplicity through a standardized multi-phosphor combination approach.
Solution Approach 2:
The patent uses a composite phosphor system combining three different phosphor materials with specific emission characteristics. This composite approach creates a synergistic effect where the combination of phosphors provides superior color rendering (CRI≥90) compared to individual phosphors, while still using conventional blue LED excitation sources.
2Manufacturing precision
If red phosphor content is increased to provide high color rendering white light source, then color rendering is improved, but cost remarkably increases due to expensive red phosphors
Solution Approach 1:
The patent replaces expensive red phosphors with cheaper alternative phosphors (first phosphor in 495-510nm range, third phosphor in 580-605nm range) that can achieve the same color rendering effect. This substitution maintains high CRI (≥90) while significantly reducing material costs by using more economical phosphor options.
Solution Approach 2:
The patent changes the wavelength parameters of the phosphor system from traditional red phosphor emission to a distributed multi-wavelength approach. By specifying phosphors in particular wavelength ranges (495-510nm, 550-555nm, 580-605nm) rather than focusing on red region only, the system achieves superior color rendering with different, more cost-effective materials.
3Ease of operation
If blue LED and yellow phosphor are combined to implement white light, then ease of operation is improved, but green and red components are lacking making it difficult to express natural colors
Solution Approach 1:
The patent segments the missing green and red spectral components by introducing three specific phosphors: first phosphor (495-510nm) fills the green-blue gap, second phosphor (550-555nm) provides the missing green region, and third phosphor (580-605nm) extends into the yellow-orange region. This segmentation strategically addresses the spectral deficiencies of simple blue LED+yellow phosphor systems.
Solution Approach 2:
The patent creates a universal phosphor combination that works with standard blue LED excitation sources while providing enhanced color rendering. The multi-phosphor system serves multiple functions simultaneously: maintaining compatibility with existing blue LED technology, filling spectral gaps in green and red regions, and achieving high CRI (≥90), thereby expressing natural colors effectively.
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 high color rendering and efficiency while reducing costs by using a combination of phosphors that emit light in regions with high eye response factors, eliminating the need for numerous expensive red phosphors and improving phosphor mixing freedom for optimal color coordinates.
Implementation Method 1
phosphors including first to third phosphors, wherein the first phosphor is excited by light emitted from the blue LED, emits light having a main wavelength of about 495 nm to about 510 nm
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A light emitting device is provided. The light emitting device includes a blue light emitting diode (LED); and phosphors including first to third phosphors, wherein the first phosphor is excited by light emitted from the blue LED, emits light having a main wavelength of about 495 nm to about 510 nm, and includes BaSi2O2N2:Eu or (Bax,Sr1-x)Si2O2N2:Eu where 0<x<1, the second phosphor is excited by light emitted from the blue LED, emits light having a main wavelength of about 555 nm to about 575 nm, and includes Lu3Al5O12:Ce or (Lux,Gd1-x)3Al5O12:Ce where 0<x<1, and the third phosphor is excited by light emitted from the blue LED, emits light having a main wavelength of about 580 nm to about 605 nm, and includes (Cax,Sr1-x)AlSiN3:Eu where 0<x<1.