Solid-State Lighting Device with Multi-Hue Emission
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Solution Overview
Problem
Conventional lighting devices, particularly those using incandescent and fluorescent lights, are inefficient in energy usage and have limitations in color rendering index (CRI), leading to poor color reproduction and short lifespans, while solid-state light emitters like LEDs struggle to produce white light effectively with high efficiency and acceptable color temperature.
Innovation Solution
A lighting device that combines multiple sources of visible light, including solid-state light emitters and luminescent materials, to produce a white or near-white illumination that is spectrally enhanced to achieve a higher CRI, using a combination of light sources that, when mixed, fall on or near the blackbody locus on the CIE Chromaticity Diagram, thereby improving color rendering and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If incandescent light bulbs are used, then color reproduction is excellent (CRI greater than 95), but energy efficiency is very poor (90% of electricity released as heat)
Solution Approach 1:
The patent combines multiple solid state light emitters with different emission spectra (e.g., blue LED with yellow phosphor, red LED, green LED) to create a composite light source that achieves both high energy efficiency and excellent color reproduction (CRI greater than 95). This merging of multiple light sources resolves the contradiction by combining the efficiency of LEDs with the color quality of incandescent bulbs.
Solution Approach 2:
The patent uses composite luminescent materials including multiple phosphors (yellow phosphor, red phosphor, green phosphor) combined with solid state light emitters to create a composite lighting system that achieves both high efficiency and superior color rendering. The composite approach allows optimization of both energy conversion and spectral output.
2Loss of energy
If fluorescent light bulbs are used, then energy efficiency is improved (10x better than incandescent), but color reproduction deteriorates (CRI of 70-80)
Solution Approach 1:
The patent merges multiple solid state light emitters with complementary color spectra to achieve a combined output that covers the full visible spectrum with high efficiency. By combining blue, red, and green emitters with appropriate phosphors, the system achieves CRI greater than 95 while maintaining LED-level energy efficiency.
Solution Approach 2:
The patent applies local quality by using different phosphor materials with specific emission characteristics in different regions of the spectrum. Each phosphor is selected to fill specific spectral gaps, ensuring excellent color reproduction across all wavelengths while maintaining overall system efficiency.
3Loss of energy
If solid state light emitters like LEDs are used, then energy efficiency is high and lifespan is long, but ability to produce white light with acceptable color temperature and CRI is poor
Solution Approach 1:
The patent combines multiple solid state light emitters (blue LED, red LED, green LED) with multiple phosphor materials to create a unified lighting system that produces high-quality white light with CRI greater than 95 and adjustable color temperature, while maintaining the high energy efficiency and long lifespan of solid state technology.
Solution Approach 2:
The patent uses parameter changes by adjusting the ratios and types of phosphors (yellow phosphor, red phosphor, green phosphor) to optimize the spectral output. By varying phosphor concentrations and emitter characteristics, the system achieves precise control over color temperature and CRI while maintaining high efficiency.
4Ease of manufacture
If conventional light fixtures are used with periodic replacement, then initial cost is low, but maintenance cost and downtime increase due to frequent changes
Solution Approach 1:
The patent employs solid state light emitters with lifespans measured in decades (44,000+ hours) replacing conventional bulbs that last only 750-1000 hours. Although the initial cost of solid state emitters is higher, the extended lifespan eliminates periodic replacements, reducing maintenance time and downtime, particularly in hard-to-access locations.
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 provides a high-efficiency solid-state white light source with improved CRI and longer lifespan, capable of accurately rendering a wide range of colors, including red and green, while maintaining energy efficiency and simplicity in control circuitry.
Implementation Method 1
Light emitting diodes are well-known semiconductor devices that convert electrical current into light
Implementation Method 2
one or more luminescent materials (e.g., one or more phosphors)
Data Source
AI summary
A lighting device comprising sources of visible light comprising solid state light emitters and/or luminescent materials emitting three or four different hues. A first group of the sources, when illuminated, emit light of two hues which, if combined, would produce illumination having coordinates within an area on a 1931 CIE Chromaticity Diagram defined by points having coordinates: 0.59, 0.24; 0.40, 0.50; 0.24, 0.53; 0.17, 0.25; and 0.30, 0.12. A second group of the sources is of an additional hue. Mixing light from the first and second groups produces illumination within ten MacAdam ellipses of the blackbody locus. Also, a lighting device comprising a white light source having a CRI of 75 or less and at least one solid state light emitters and/or luminescent material. Also, methods of lighting.