A DLC Coating definition means diamond-like carbon coating+Anti-Reflective coating. For harsh environmental applications, DLC coating on the exterior surface of the Germanium/Silicon, coupled with a high efficiency AR coating on the opposite side provides both protection and the highest transmission available. The DLC Coating meets not only severe abrasion test requirements, but also various wiper, sand, sun and rain tests. Anti-reflective coatings are relatively soft and not suitable for applications where they will be exposed to harsh conditions. Where necessary, tougher AR coatings in the form of diamond-like carbon (DLC) are available.DLC coatings have been qualified for military platforms for outdoor environmental.