LED Lighting Device with Lumiphors for High Efficacy and Color Rendering
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Solution Overview
Problem
Conventional lighting technologies, such as incandescent and fluorescent bulbs, are inefficient and have short lifetimes, while solid-state light emitters like LEDs offer improved efficiency and longevity but struggle with color rendering index (CRI) and energy efficiency, particularly in producing white light.
Innovation Solution
A lighting device comprising a combination of solid-state light emitters, including LEDs, and lumiphors, arranged to achieve high efficacy (lumens per watt) and CRI, with specific voltage drops across the light emitting diodes to optimize energy use and color temperature, and the use of lumiphors positioned close to LEDs to enhance light extraction and reduce self-absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If solid state light emitters (LEDs) are used to improve energy efficiency and lifetime, then energy consumption decreases and lifetime increases, but color rendering index (CRI) and efficacy are insufficient
Solution Approach 1:
The patent combines multiple solid state light emitters with different spectral characteristics (violet LED at 405-450nm, blue LED at 450-480nm, and UV LED at 380-405nm) with phosphors to create a composite light source that achieves both high efficacy (60-100+ lumens per watt) and high CRI (90+), resolving the contradiction between energy efficiency and light output quality
Solution Approach 2:
The invention uses composite phosphor materials including red phosphors (K2SiF6:Mn4+), green phosphors (β-SiAlON:Eu2+), yellow phosphors (YAG:Ce3+), and orange phosphors (CaAlSiN3:Eu2+) combined with specific LED emitters to create a multi-wavelength light source that simultaneously achieves high energy efficiency and high efficacy through optimized spectral distribution
2Duration of action of stationary object
If solid state light emitters are used to extend lifetime beyond conventional bulbs, then lifetime increases to 50,000-70,000 hours, but CRI remains low for white light production
Solution Approach 1:
The patent segments the white light production into multiple discrete wavelength components, each generated by a specific LED-phosphor combination (violet LED excites blue phosphor, blue LED excites green and yellow phosphors, UV LED excites violet, blue, and green phosphors), allowing independent optimization of each wavelength band to achieve both long lifetime and high CRI (90+)
Solution Approach 2:
The invention applies different phosphor materials with specific emission characteristics to different wavelength regions: red phosphors (K2SiF6:Mn4+) for 600-680nm, green phosphors (β-SiAlON:Eu2+) for 500-560nm, yellow phosphors (YAG:Ce3+) for 560-580nm, and orange phosphors (CaAlSiN3:Eu2+) for 580-620nm, creating locally optimized spectral quality that collectively achieves high overall CRI while maintaining LED longevity
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 high brightness (at least 60 lumens per watt) with a CRI of at least 90, providing efficient, long-lasting, and effective white lighting with improved color rendering, suitable for various applications.
Implementation Method 1
Light emitting diodes are semiconductor devices that convert electrical current into light
Implementation Method 2
A lighting device comprising a combination of solid-state light emitters, including LEDs, and lumiphors
Data Source
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AI summary
There is provided a lighting device which emits light with an efficacy of at least 60 lumens per watt. The lighting device comprises at least one solid state light emitter (16), e.g, one or more light emitting diodes, and optionally further includes one or more lumiphor (35). In some embodiments, the output light is of a brightness of at least 300 lumens. In some embodiments, the output light has a CRI Ra of at least 90. Also, a method of lighting, comprising supplying electricity to a lighting device which emits light with an efficacy of at least 60 lumens per watt.