Heat rays reflecting film

摘要

A heat rays reflecting film composed of dielectric thin layers (nH layers) having a relatively high refractive index and dielectric thin layers (nL layers) having a relatively low refractive index which are alternately piled on one another, is disclosed. The first layer of the heat rays reflecting film, which contacts with the air is nL layer and the undermost layer which contacts with the window glass is nH layer. The optical thickness of the first layer is less than lambda /4 while that of the other layers is lambda /4. And the thickness of each layer is expressed by the formula: optical thickness/nv wherein nv is the refractive index for visible rays.