Research On 8μm～12μm Infrared Antireflection Coating

As an important atmospheric window,8μm～12μm is the commonly used infrared wavelengths, covers the infrared wave given out by the heat source such as engine, driving equipment and gas. It’s used to detect targets such as vehicles, aircraft and ships.The technology was studied by this article is making Antireflection Coating film on the infrared optical element in the aiming system of Military helicopters.There are two kind substrate materials used in the system.Germanium (Ge) and Zinc sulfide (ZnSe).The requirements of the coating is:The average transmission rate is greater than 95% within the scope of 8μm-12μm.We used the electron beam evaporation and ion assisted deposition technology in this subject. According to the theory of thin film technology, We study and analysis the optical properties of some thin film materials.we simulation process with the computer software.We analyzed the factors which influencing the features of the film coating process. Finally we got the qualified design.Through trial and error, the Antireflection Coating film on the substrates was successful made.Tests show that the average transmission rate within the scope of 8μm-12μm is 96.1%(Ge)and 97.8%(ZnSe).And The sample can withstand high temperature, damp and hot environment test.