Nanoparticle Diffuser Layout for Uniform Blue-Sky Illumination
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Solution Overview
Problem
Lighting devices with edge incidence systems face issues in reproducing a natural blue sky due to concentration-dependent color and brightness unevenness caused by nanoparticles, either resulting in insufficient illumination or excessive wavelength dispersion.
Innovation Solution
A diffuser design that incorporates a specific relationship between nanoparticle concentration, particle radius, scattering efficiency, mean free path, and light guiding length to optimize light scattering and emission, ensuring uniform illumination and color reproduction across the emission surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the concentration of nanoparticles is increased to enhance scattering effect, then the amount of illumination light extracted through the light emission surface increases, but color unevenness and brightness unevenness occur in the light emission surface
Solution Approach 1:
The patent applies parameter changes by establishing a specific mathematical relationship between nanoparticle concentration (N), particle radius (A), and the ratio of light guiding length to mean free path (α). By controlling these parameters to satisfy the formula 0.7 ≤ α ≤ 3.2, the patent optimizes the scattering effect while preventing color and brightness unevenness, thus resolving the contradiction between illumination intensity and color uniformity.
Solution Approach 2:
The patent applies local quality by creating different optical conditions in different regions of the diffuser. Through the controlled nanoparticle distribution and light guiding structure, the patent ensures that each region of the light emission surface receives appropriate scattered light, achieving uniform color and brightness across the entire surface while maintaining high illumination intensity.
2Manufacturing precision
If the concentration of nanoparticles is decreased to reduce wavelength dispersion, then color unevenness is reduced, but the amount of illumination light extracted through the light emission surface becomes insufficient
Solution Approach 1:
The patent resolves this contradiction by changing the parameters of nanoparticle concentration, particle size, and light guiding length to satisfy the specific relationship 0.7 ≤ α ≤ 3.2. This parameter optimization ensures sufficient illumination light extraction while maintaining color uniformity across the light emission surface.
Solution Approach 2:
The patent uses composite materials consisting of a base material and dispersed nanoparticles with specific properties. By carefully selecting and combining materials with appropriate optical characteristics, the patent achieves both sufficient light extraction and uniform color distribution, resolving the contradiction between illumination intensity and color uniformity.
3Illumination intensity
If the light guiding length is increased to improve light distribution, then scattered light emission is enhanced, but the mean free path becomes insufficient leading to color unevenness
Solution Approach 1:
The patent applies parameter changes by establishing a specific relationship between light guiding length (Zd), mean free path (MFP), and nanoparticle concentration. By controlling the ratio α = Zd/MFP to satisfy 0.7 ≤ α ≤ 3.2, the patent optimizes light distribution while preventing color unevenness, thus resolving the contradiction between scattered light emission and color uniformity.
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 diffuser effectively reproduces a natural blue sky with reduced color and brightness unevenness by balancing nanoparticle concentration and light guiding properties, enhancing the overall lighting experience.
Implementation Method 1
a light source is disposed on the upper side (e.g., a back surface side) of a diffused light generator (also referred to as a 'diffuser') that is formed by dispersing nanoparticles for generating diffused light (e.g., Rayleigh scattered light) in a base material
Data Source
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AI summary
A diffuser (20) includes a light incident surface (21), a light guiding and diffusing portion (22) to generate scattered light (Ls) by guiding incident light (Li) and scattering it with nanoparticles (26), and a light emission surface (23). A correlated color temperature of the scattered light is higher than a correlated color temperature of the incident light. The diffuser satisfies MFP=1/π×A2×Qs×N=αZd, and 0.4≤α≤5 where N denotes a number of the nanoparticles included in a unit volume of the light guiding and diffusing portion, A denotes an average particle radius of the nanoparticles, Qs denotes a scattering efficiency determined by a combination of the nanoparticles and a medium of the light guiding and diffusing portion, MFP denotes a mean free path for light of a design wavelength set in a range of 450 nm to 650 nm, Zd denotes a length of the light guiding and diffusing portion in a light guiding direction of the incident light, and α denotes a coefficient.