OPTICAL ELEMENT, WINDOW MATERIAL, FITTING, AND SOLAR SHADING DEVICE

摘要

An optical element is provided with a wavelength-selective reflection layer having a five-layer configuration in which high-refractive-index layers and metal layers are alternately stacked. The present invention is designed so that the ratio ± of an optical film thickness d b of the entire metal layer relative to an optical film thickness d a of the high-refractive-index layers as a whole, and the ratio ² (= d 3 /d 1 ) of an optical film thickness d 3 of the third high-refractive-index layer with respect to the optical film thickness d 1 of the first high-refractive-index layer as viewed from either the first optical layer side or the second optical layer side are included within a predetermined range.