Through vacuum spraying or magnetron sputtering technology, aluminum, gold, copper, silver and other metal are made into multilayer to dense high heat insulating metal film layer. The shell layer electrons in metallic materials (free electrons) are generally not bound by atomic nuclei, and when irradiated by light waves, the electric field of light waves causes the free electrons to absorb the energy, and produce the same frequency oscillation as the light, which emits the same frequency light as the original light, which is called light reflection.
The higher the conductivity of metal, the lighter the penetration depth and the higher the reflectivity. These layers of metal will selectively light all kinds of heat energy in the sun, including infrared, ultraviolet and visible light energy, and then, with the color of the film on the absorption of solar heat radiation, and then released two times outward, with the outdoor air flow away a part of the heat. So as to effectively play the role of heat insulation.