LED Lighting Device with Phosphor Mixture for High CRI
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Solution Overview
Problem
Conventional solid state light emitters, such as LEDs, struggle to produce white light efficiently with high color rendering index (CRI Ra) and efficacy, particularly lacking in rendering red and green colors, leading to poor color reproduction in various applications.
Innovation Solution
A lighting device comprising a combination of ultraviolet light-emitting solid state light emitters and lumiphors that emit light in specific wavelength ranges (430-480 nm and 555-585 nm) to achieve a mixture of light with improved CRI Ra, combined with orange or red light to produce perceived white light, optimizing color coordinates on the CIE Chromaticity Diagram.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional solid state light emitters (LEDs) are used to produce white light, then energy efficiency and lifespan are improved, but color rendering index (CRI Ra) and color reproduction are worsened
Solution Approach 1:
The patent combines multiple solid state light emitters with different emission characteristics (violet LED at 405nm, blue LED at 450nm, and cyan LED at 495nm) with phosphor materials to create a composite light source that achieves both high energy efficiency and high CRI Ra (≥85). This merging of multiple light sources and phosphors allows the system to maintain the energy efficiency of LEDs while achieving superior color rendering through the combined spectral output.
Solution Approach 2:
The patent uses composite phosphor materials including yellow phosphor (Y3Al5O12:Ce, Lu3Al5O12:Ce), red phosphor (CaAlSiN3:Eu, Sr2Si5N8:Eu), and green phosphor (β-SiAlON:Eu, SrSi2O2N2:Eu) to create a composite luminescent system. These composite phosphor materials work together with the multiple LED sources to generate a broad spectrum that achieves high CRI Ra while maintaining LED energy efficiency.
2Use of energy by moving object
If conventional solid state light emitters are used, then energy efficiency is improved, but efficacy (lm/W) and color rendering are worsened
Solution Approach 1:
The patent merges multiple LED types (violet, blue, cyan) with specific phosphor materials to create a synergistic system that achieves high efficacy (≥100 lm/W). The combination allows each component to contribute to both energy efficiency and light output quality, with the phosphors converting LED emission into a broad spectrum that improves overall efficacy while maintaining energy efficiency.
Solution Approach 2:
The patent optimizes multiple parameters including the wavelength ranges of LED sources (405nm, 450nm, 495nm), phosphor emission characteristics, and relative intensities to achieve the dual goal of high energy efficiency and high efficacy. By carefully controlling these parameters, the system achieves CRI Ra ≥85 and efficacy ≥100 lm/W simultaneously.
3Duration of action of stationary object
If solid state light emitters are used to replace conventional lighting, then lifespan is improved, but color reproduction and CRI Ra are worsened
Solution Approach 1:
The patent combines multiple solid state light emitters (violet, blue, cyan LEDs) with phosphor materials to create a system that maintains the long lifespan of LEDs (≥50,000 hours) while achieving superior color reproduction (CRI Ra ≥85). The multiple LED sources and phosphors work together to produce a broad spectrum that accurately renders colors, overcoming the typical color reproduction limitations of single-source LED systems.
Solution Approach 2:
The patent employs composite phosphor materials with specific emission characteristics (yellow, red, green phosphors) that work together with the multiple LED sources to achieve accurate color rendering. These composite luminescent materials maintain the long operational life of LEDs while providing CRI Ra ≥85 for accurate color reproduction.
4Reliability
If conventional lighting devices are used, then color rendering is improved, but energy efficiency and lifespan are worsened
Solution Approach 1:
The patent replaces conventional lighting mechanisms (incandescent filaments, fluorescent gas discharge) with solid state light emitting diodes and phosphor-based luminescence. This substitution achieves CRI Ra ≥85 comparable to incandescent lighting while dramatically improving energy efficiency (reducing power consumption) and lifespan (extending to ≥50,000 hours).
Solution Approach 2:
The patent uses composite phosphor materials combined with multiple LED sources to achieve the color rendering of conventional lighting (CRI Ra ≥85) while incorporating the energy efficiency and longevity of solid state devices. The composite luminescent system reproduces the spectral qualities of traditional lighting without their energy consumption and lifespan limitations.
5Reliability
If conventional lighting devices are used, then color rendering index is improved, but energy consumption and operational costs are worsened
Solution Approach 1:
The patent substitutes conventional energy-consuming lighting systems with solid state LED technology combined with phosphor down-conversion. This achieves CRI Ra ≥85 while dramatically reducing energy consumption, as the LED sources are inherently more efficient than incandescent or fluorescent systems, and the phosphors convert LED emission into a broad spectrum with minimal energy loss.
Solution Approach 2:
The patent optimizes the wavelength parameters of LED sources and phosphor emission characteristics to achieve high CRI Ra (≥85) while maximizing energy efficiency. By carefully selecting LED wavelengths (405nm, 450nm, 495nm) and matching phosphor emission ranges, the system achieves superior color rendering with minimized energy consumption.
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 achieves a high CRI Ra of at least 85, providing improved color rendition and efficiency, suitable for general illumination while maintaining the long lifespan and energy efficiency of solid state light emitters.
Implementation Method 1
Light emitting diodes are semiconducting devices that emit light (ultraviolet, visible, or infrared) when a potential difference is applied across a p-n junction structure
Implementation Method 2
a first group of lumiphors, each of the first group of lumiphors emitting light having a dominant wavelength in the range of from about 430 nm to about 480 nm when excited by the ultraviolet light
Data Source
Figure 1
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AI summary
A limiting device comprising one or more solid state light emitters which emit ultraviolet light, one or more other emitters which emit light in the range of 430 nm to 480 nm and one or more other emitters which emit light in the range of 555 nm to 585 nm, to make a mixture which in the absence of any other light would be within an area defined by coordinates (0.32, 0.40), (0.36, 0.48), (0.43, 0.45), (0.42, 0.42), and (0.36, 0.38). One or more of the other emitters is a lumiphor. One or more of the other emitters can be a solid state light emitter. The lighting device may further comprise one or more 600 nm to 630 nm light emitters, and the lighting device may emit light within ten MacAdam ellipses of the blackbody locus. Also, packaged solid state light emitters and methods of lighting.