Patent ID: 11874431
Assignee: MITSUBISHI ELECTRIC CORPORATION
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC F  G | IPC F  G

Claim 0:
1. A diffuser comprising:
at least one light incident surface on which light emitted from a light source is incident as incident light;
a light guiding and diffusing portion including a medium and nanoparticles present in the medium, the light guiding and diffusing portion generating scattered light by guiding the incident light and scattering the incident light with the nanoparticles; and
a first light emission surface to emit the scattered light, wherein
a correlated color temperature of the scattered light is higher than a correlated color temperature of the incident light, and
the diffuser satisfies:

MFP=1/(π×A2×Qs×N)=αZd,

0.4≤α≤5, where N denotes a number (particles/mm3) of the nanoparticles included in a unit volume of the light guiding and diffusing portion, A denotes an average particle radius (mm) of the nanoparticles, Qs denotes a scattering efficiency determined by a combination of the nanoparticles and the medium of the light guiding and diffusing portion, R denotes a ratio of a circumference of a circle, MFP denotes a mean free path (mm) for light of a wavelength of 550 nm, Zd denotes a length (mm) of the light guiding and diffusing portion in a light guiding direction of the incident light, and a denotes a coefficient.