LIGHT DISTRIBUTION CONTROL DEVICE, BLIND, PARTITION, CURTAIN, TENT AND ILLUMINATOR

摘要

A light distribution control device comprising a generally plane- or film- shaped optical diffusion structure having an optical transmittance or reflectivity and including a multiplicity of ridges arrayed in parallel with each other on its one face. Each ridge forms a part of a circle generally in a section normal to the longitudinal direction thereof, and is made so smooth on its surface as not to cause a drastic irregular diffusion of light. In the diffraction grating effect to be caused by the parallel array of the multipl e ridges, the ratio of the amount of diffractive light to the amount of incide nt light is adjusted by selecting the angle of circumference and the maximum diameter of the section of each ridge. Where an optical beam is introduced t o the face of the optical diffusion structure, the projection of the diffusion distribution on the plane normal to both the longitudinal direction of the ridges and the face of the structure is generally symmetric with respect to the axis of the normal line at the incident point irrespective of the incidence angle of the optical beam.