Exposed coating design includes a substrate with an optical filter coating either on one surface, or on both surfaces. This type of filters must be handled with care as the soft filter coating is completely exposed.



The filter consists of two substrates with optical coatings facing each other so that the optical coatings are completely enclosed. As shown on a diagram, a spacer ring is placed between the substrates to form a small air gap sealed by edge sealant.



Exposed coating or enclosed filter designs can be supplied in metal mounting rings, if required. The rings are constructed from aluminum. Please note that mounting of a filter increases the outside diameter of the assembly.