Ir reflective film

Abstract

A translucent or transparent film or sheet device shows angular-independent IR reflectance, which comprises a substrate (1) covered with a layer of a dielectric high refractive index material (4) containing a thin metallic layer (3) embedded in said material, and a further layer (5) of translucent or transparent material covering said layer (4) of dielectric high refractive index material, characterized in that the embedded metal layer (3) is periodically interrupted with a periodicity of 50 to 800 nm such that metal covers at least 70% of the substrate area. The device may advantageously be integrated into a window, a glass facade element or especially onto a photovoltaic (PV) device, where it reduces the fraction of IR radiation passing into the building, or reduces heat take-up and thus lowers the operating temperature and improves the efficiency of the PV cell.

Dependencies are inferred from the claim text.