Diamond-like Carbon Coatings on Polymers

The purpose of this proposal is to demonstrate the effectiveness of an innovative multilayer scratch, abrasion, and ballistic impact resistant protective coating for eyewear that uses a Diamond-Like-Carbon (DLC) coating as the topcoat. The design consists of an optically thick buffer layer that is first deposited on the polycarbonate that has a refractive index closely matched to that of the polycarbonate substrate. This layer provides an optically transparent and mechanically resilient “foundation” and substantially improves the load bearing capability of the plastic substrate. The optical index match allows the coating thickness to be adjusted to maximize mechanical performance without affecting the optical performance. This thick buffer layer is then followed with a series of thinner layers including a DLC top-coat to provide excellent scratch, abrasion and ballistic impact resistance. The additional layers between the DLC and buffer layer allow improved optical performance by impedance matching the layer structure to air. The result of this optimized layer structure is a dramatically improved wear resistance, including abrasive and impact, when compared to the current polycarbonate lenses with scratch resistant AR coatings. The coating can be applied inexpensively in Acree’s Large Volume Coater (LVC).