Abstract: Polyimide had the characteristics such as resistance to high temperatures, flexibility, easy adhesion, good mechanical extensibility and tensile strength, we prepared infrared thermal insulation and protective films on a flexible polyimide material with a thickness of 125 μm. During the preparation process, the adhesion of the film layer on the flexible substrate could be improved by adjusting the energy of the ion source. Based on the principle of least squares, a relationship formula was established between the optical constants of the film material and temperature to solve the influence of temperature changes on the optical performance of the thin film. In the deposition of diamond-like carbon (DLC) film, the preheating method was used to solve the problem of uneven film thickness caused by the deformation of the flexible substrate. The infrared spectroscopy detection and analysis show that the infrared thermal insulation film prepared on the polyimide substrate meets the usage requirements.

Key words: infrared thin film, polyimide, flexible substrate, diamond-like carbon film, preparation process