White Light Source Phosphor Tuning for Sunlight-Like Illumination
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Solution Overview
Problem
Existing artificial light sources fail to accurately reproduce the subtle variations in sunlight due to regional differences and time changes, affecting the perception of colors in works of art and human comfort, while also emitting harmful ultraviolet and blue light components.
Innovation Solution
A white light source system using LED modules with controlled light emission intensities and a database to mimic sunlight's spectral variations, incorporating phosphors and filters to reduce harmful emissions, and reproduce correlated color temperatures with deviations from blackbody radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If sunlight is used for illumination, then all colors existing in nature can be reproduced as original colors, but ultraviolet components cause fading and embrittlement of artworks
Solution Approach 1:
The patent extracts only the beneficial visible spectrum components of sunlight (380-780nm) while eliminating the harmful ultraviolet components. This is achieved by using LED excitation sources that do not emit UV and phosphors that convert the LED light into a sunlight-like spectrum without UV content.
Solution Approach 2:
The patent changes the spectral parameters by using multiple phosphors with different emission characteristics (yellow phosphor with 560-580nm peak, red phosphor with 610-650nm peak, green phosphor with 520-540nm peak) to reconstruct the sunlight spectrum. By adjusting phosphor ratios and particle sizes, the spectral distribution is optimized to match natural sunlight.
2Duration of action of stationary object
If early stage LED illumination combining blue LED and yellow phosphor is used, then energy saving and long lifetime are achieved, but only unnatural white light lacking warmth can be reproduced
Solution Approach 1:
The patent uses composite phosphor materials including yellow phosphor (Y3Al5O12:Ce), red phosphor (CaAlSiN3:Eu), and green phosphor (β-SiAlON:Eu) in specific combinations. These composite phosphor layers convert the blue LED light (430-470nm) into a full-spectrum white light that reproduces sunlight characteristics while maintaining LED energy efficiency and longevity.
3Object-affected harmful factors
If artificial light sources are used to protect artworks from ultraviolet, then harmful emissions are reduced, but the ability to reproduce sunlight accurately is compromised
Solution Approach 1:
The patent introduces phosphors as intermediary materials that mediate between the blue LED excitation source and the final white light output. The phosphors absorb blue light and re-emit it as a broad spectrum including yellow, red, and green components, creating sunlight-like illumination without UV content.
4Illumination intensity
If multiple phosphors with different characteristics are combined, then sunlight spectral variations can be reproduced, but device complexity increases
Solution Approach 1:
The patent merges multiple phosphor types (yellow, red, green) into a single integrated phosphor layer or closely positioned layers that are simultaneously excited by the blue LED. This combining approach creates a unified light output that reproduces sunlight spectrum without requiring separate controllable light sources for each wavelength region.
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 system provides natural illumination that accurately reproduces sunlight's spectral variations, enhances color perception in art appreciation, and reduces harmful emissions, offering a comfortable and natural lighting experience.
Implementation Method 1
a first converter including first phosphors and a first resin, each first phosphor having different half-value widths, the second light emitter has a second converter including second phosphors and a second resin
Implementation Method 2
incorporating phosphors and filters to reduce harmful emissions
Data Source
AI summary
A light emitting device including a substrate, a first light emitter to emit light having a first color temperature, and a second light emitter to emit light having a second color temperature, in which the first light emitter has a first converter including first phosphors and a first resin, each first phosphor having different half—value widths, the second light emitter has a second converter including second phosphors and a second resin, each second phosphor having different peak wavelengths, at least one phosphor of the first converter has a half-value width of 33 nm to 110 nm, a distance between peak wavelengths of at least two phosphors of the second converter is 150 nm or less, and at least one phosphor of the first converter has a particle size of 5 um to 50 um.