White Light Source Phosphor Composition for Natural-Like Spectrum Stability
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Solution Overview
Problem
Current white light sources using LEDs have light emission spectra significantly different from natural light, which can disrupt human circadian rhythms when used for extended periods.
Innovation Solution
A white light source system comprising a blue LED with a phosphor layer containing at least three types of phosphors (blue-green, green, and red) that emit light within specific peak wavelengths, designed to match the spectral luminous efficiency of natural light, with a phosphor layer thickness of 0.01 to 3 mm and an average particle diameter of 1 to 80 µm, ensuring minimal chromaticity change and brightness degradation over 6000 hours.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If conventional white LEDs use blue LEDs with YAG phosphors, then energy saving and long service life are achieved, but the light emission spectrum deviates significantly from natural light, causing adverse effects on human circadian rhythms
Solution Approach 1:
The patent applies parameter changes by modifying the phosphor composition to include multiple types (yellow, orange, red) with different emission characteristics. This changes the spectral parameters of the emitted light to better match natural light while maintaining the energy efficiency and long service life of LED technology.
Solution Approach 2:
The patent uses composite materials by combining multiple phosphor types (yellow Y3Al5O12:Ce, orange CaAlSiN3:Eu, red CaAlSiN3:Eu) with the blue LED chip. This composite phosphor layer creates a combined emission spectrum that closely resembles natural light, resolving the contradiction between LED durability and circadian rhythm compatibility.
2Illumination intensity
If blue LED peak intensity is increased to achieve bright white light, then illumination intensity is improved, but the deviation from natural light spectrum increases, strengthening blue light's adverse effects
Solution Approach 1:
The patent changes the spectral parameters by incorporating phosphors with emission peaks at different wavelengths (yellow at 560nm, orange at 600nm, red at 630nm). This distributes the luminous intensity across multiple wavelengths, maintaining overall brightness while reducing the relative intensity of harmful blue light compared to natural light.
Solution Approach 2:
The patent applies local quality by assigning different functional roles to different phosphor components. The yellow phosphor provides general illumination, while the orange and red phosphors specifically address the spectral deficiency in conventional LEDs, creating localized spectral enhancement that reduces blue light dominance.
3Illumination intensity
If multiple phosphors with different emission peaks are combined, then spectral luminous efficiency is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple phosphor materials into a single integrated phosphor layer that can be applied directly to the LED chip. This combining approach achieves complex spectral requirements through one unified component rather than multiple separate optical elements, thereby improving spectral luminous efficiency while limiting complexity growth.
Solution Approach 2:
The patent creates a universal phosphor layer that performs multiple functions simultaneously: converting blue LED light to yellow, orange, and red wavelengths, and collectively forming a natural-light-like spectrum. This multi-functional design achieves high spectral efficiency without proportionally increasing device complexity.
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 reproduces the light emission spectrum of natural light, reducing adverse effects on human circadian rhythms and maintaining high reliability and brightness over time, effectively mimicking natural light exposure.
Implementation Method 1
a blue light emitting diode (blue LED) having a light emission peak wavelength in a range of 421 to 490 nm
Implementation Method 2
the phosphor comprises at least three or more types of phosphors that emit blue-green, green, yellow, and red light, respectively, the phosphor being composed of a combination of at least green, yellow, and red phosphor, wherein the white light source satisfies a relational equation... wherein the phosphor is excited by the light emitted from the blue light emitting diode
Data Source
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AI summary
Provided is a white light source, comprising a blue light emitting LED with a peak light emitting wavelength of 421nm-490nm and a fluorescent light body layer further comprising a fluorescent light body and a resin, With the emission spectrum of the white light source designated P(λ), the emission spectrum of the black body radiation which denotes a color temperature which is the same as that of the white light source desigiated B(λ), the spectrum of the spectral luminous efficiency designated V(λ), the wavelength at which P(λ) × V(λ) is at a maximum designated λmaxl, and the wavelength at which E(λ) × V(λ) is at a maximum designated λmax2, the relational formula -0.2≤[(P(λ) × V(λ))/P(λmaxl) × V(λmaxl))-(B(λ) × V(λ))/(B(λmax2) × V(λmax2))]≤+0.2 is satisfied, and the size of the color change between the initial lighting of a white light source which uses a CT, chromaticity diagram and after 6000 hours of consecutive lighting is less than 0.010. It is possible, with this configuration, to provide a white light source which has an equivalent emission spectrum to natural light, as well as a white light source system using the white light source.