CVD zinc sulfide (ZnS) is a chemical inert material with high purity, insoluble in water, moderate density and easy to process. It is widely used in the fabrication of infrared windows, fairing and infrared optical elements. Like zinc selenide (ZnSe) materials, zinc sulfide (ZnS) is also a good material with good uniformity and consistency in the refractive index. It has good image transmission performance at the 8-12 U M band, but it begins to have some absorption after 10um. The material also has high transmittance in the mid infrared band, but with the shorter wavelength, the absorption and scattering are enhanced. Compared with zinc selenide (ZnSe), zinc sulfide (ZnS) has high hardness and breaking strength, which is two times higher than that of zinc selenide (ZnSe). The diameter range of the ZNSE window or lens produced by our company is: 5~220mm, the surface precision is up to 20/10, and the surface roughness is up to: lambda /10@633nm (the ratio of the thickness to diameter of the lens should conform to the processing ratio).