Wavelength-Selective Light Diffuser for LED Glare Reduction
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Solution Overview
Problem
Conventional light diffusion covers for LED luminaires lack wavelength selectivity, failing to effectively diffuse light in the blue light region around 450 nm, which is harmful to the human eye, while maintaining sufficient brightness and preventing glare.
Innovation Solution
A light diffusion cover comprising a thermoplastic resin and transparent particles with a specific wavelength selectivity in the rectilinear light ratio, ensuring higher diffusion of 450 nm light and maintaining adequate brightness by adjusting the volume-average particle size, refractive index difference, and total light transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional light diffusion cover with transparent particles is used, then light diffusion is achieved, but wavelength selectivity is lacking and blue light around 450 nm is not effectively diffused
Solution Approach 1:
The patent applies local quality by making the light diffusion property wavelength-dependent. Specifically, the light diffuser is designed to have different light diffusion properties at different wavelengths, with enhanced diffusion capability specifically for blue light around 450 nm while maintaining appropriate diffusion at other wavelengths. This selective local optimization resolves the contradiction by providing harmful wavelength targeting without compromising overall light diffusion functionality.
Solution Approach 2:
The patent employs parameter changes by carefully controlling the volume-average particle size of transparent particles within 0.1 μm to 1 μm, and adjusting the total light transmittance to 50-85%. These parameter optimizations enable the light diffuser to achieve wavelength-selective diffusion, particularly for blue light at 450 nm, while maintaining sufficient overall light transmission. The parameter changes transform a conventional broadband diffuser into a spectrally selective one.
2Object-affected harmful factors
If light diffusion is increased to reduce glare, then brightness is reduced, but excessive diffusion loses wavelength selectivity
Solution Approach 1:
The patent applies local quality by making the light diffusion property wavelength-dependent. Specifically, the light diffuser is designed to have different light diffusion properties at different wavelengths, with enhanced diffusion capability specifically for blue light around 450 nm while maintaining appropriate diffusion at other wavelengths. This selective local optimization resolves the contradiction by providing harmful wavelength targeting without compromising overall light diffusion functionality.
Solution Approach 2:
The patent employs parameter changes by carefully controlling the volume-average particle size of transparent particles within 0.1 μm to 1 μm, and adjusting the total light transmittance to 50-85%. These parameter optimizations enable the light diffuser to achieve wavelength-selective diffusion, particularly for blue light at 450 nm, while maintaining sufficient overall light transmission.
3Adaptability or versatility
If transparent particles are added to achieve light diffusion, then light transmittance decreases, but particle size and concentration control is difficult to achieve wavelength selectivity
Solution Approach 1:
The patent employs parameter changes by carefully controlling the volume-average particle size of transparent particles within 0.1 μm to 1 μm, and adjusting the total light transmittance to 50-85%. These parameter optimizations enable the light diffuser to achieve wavelength-selective diffusion, particularly for blue light at 450 nm, while maintaining sufficient overall light transmission. The parameter changes transform a conventional broadband diffuser into a spectrally selective one.
Solution Approach 2:
The patent applies color changes by utilizing the wavelength-dependent light diffusion properties of transparent particles. The light diffuser exhibits different diffusion effects for different wavelengths, with prominent diffusion for blue light around 450 nm. This optical property variation with wavelength enables the achievement of wavelength selectivity through careful material selection and particle size control.
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 effectively alleviates glare and reduces harmful blue light exposure while preserving the brightness of the LED luminaire, making it suitable for various lighting applications.
Implementation Method 1
transparent particles... blended in a transparent thermoplastic resin... light diffusion function for diffusing light emitted from the LED light source
Implementation Method 2
light diffusion property... peaks appear at around 450 nm and around 550 nm... light diffusion property around 450 nm is prominently greater than the light diffusion property at the other wavelengths
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
There is provided a light diffuser which can alleviate glare of light emitted from a light source while preventing a decrease in brightness of the emitted light despite the presence of the light diffuser. The light diffuser contains a thermoplastic resin and transparent particles added thereto. The light diffuser has a total light transmittance in a range of 50 to 85%, and a wavelength selectivity in a rectilinear light ratio in a range of 1.5 to 5.0, as obtained by following formulas (1)-(3): wavelength selectivity in the rectilinear light ratio=rectilinear light ratio of550−nm light/rectilinear light ratio of550−nm light rectilinear light ratio of550−nm light=rectilinear light transmittance for550−nm light/total transmittance for550−nm light rectilinear light ratio of450−nm light=rectilinear light transmittance for450−nm light/total transmittance for450−nm light