Street Light Spectrum Design for Lower Insect Attraction
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Solution Overview
Problem
Optical multilayer films used in light-emitting devices are ineffective in controlling light transmission for reducing insect attraction due to incident angle dependence, resulting in insufficient reduction of the insect-attracting effect.
Innovation Solution
A light-emitting device with a light-emitting element having an emission peak wavelength between 400 nm to 490 nm and a phosphor with an emission peak wavelength between 570 nm to 680 nm, achieving a correlated color temperature of 1950 K or less, an average color rendering index of 51 or greater, and an insect-attracting index of 0.031 or less, which reduces the attraction of insects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an optical multilayer film is used to control light transmission in predetermined wavelength regions, then the insect-attracting effect can be reduced, but the control becomes ineffective due to incident angle dependence
Solution Approach 1:
The patent removes the optical multilayer film from the light-emitting device structure and replaces it with a phosphor-based wavelength conversion approach. This extraction eliminates the incident angle dependence problem while maintaining the ability to control spectral output for reducing insect attraction.
Solution Approach 2:
The patent changes the approach from using optical interference (angle-dependent) to using phosphor emission characteristics (angle-independent). By controlling the phosphor composition and excitation wavelength, the spectral distribution is adjusted to reduce insect-attracting effects without relying on angle-sensitive optical films.
2Object-affected harmful factors
If the spectral distribution is adjusted to reduce insect attraction, then the insect-attracting effect decreases, but the color rendering quality may deteriorate
Solution Approach 1:
The patent applies local quality by using multiple phosphors with different emission characteristics (yellow phosphor for 560-580nm, red phosphor for 610-680nm) to selectively shape the spectral distribution. This allows reducing insect-attracting wavelengths while maintaining or enhancing color rendering in the visible range through targeted phosphor selection and combination.
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 device effectively minimizes insect attraction while maintaining a natural color rendering property, ensuring the light emitted does not cause discomfort and has a reduced insect-attracting effect.
Implementation Method 1
a light-emitting element having an emission peak wavelength within a range from 400 nm to 490 nm
Implementation Method 2
a first phosphor having an emission peak wavelength within a range from 570 nm to 680 nm
Data Source
AI summary
Provided is a light-emitting device, a light fixture, and a street light with a further reduced insect-attracting effect. A light-emitting device includes a light-emitting element having an emission peak wavelength within a range from 400 nm to 490 nm; and a first phosphor having an emission peak wavelength within a range from 570 nm to 680 nm, wherein the light-emitting device has a correlated color temperature of 1950 K or less, an average color rendering index Ra of 51 or greater, and a full width at half maximum of an emission peak having a maximum light emission intensity in an emission spectrum of the light-emitting device of 110 nm or less, and the light-emitting device emits light having an insect-attracting index I of 0.031 or less, which is a ratio of an effective radiance of the light-emitting device in consideration of spectral luminous efficiency of insects in a range from 250 nm to 615 nm to a luminance of light emitted by the light-emitting device in a range from 380 nm to 780 nm in consideration of spectral luminous efficiency for human photopic vision specified by the CIE (International Commission on Illumination).