Improved properties of optical coatings through substrate pre-treatment

Abstract

Optical films were deposited onto float glass substrates following initial pre-treatment via a Hall-type ion source within a conventional magnetron sputtering system. Films of titania, and zinc oxide were deposited via reactive magnetron sputtering. Film properties were analysed using a range of techniques including AFM, XRD, spectrophotometry, scratch testing and wear resistance. Coatings deposited onto glass that was pre-treated with the ion source exhibited enhanced mechanical properties in comparison with those deposited onto untreated glass. In particular, film durability was increased substantially and surface roughness was reduced, without any detrimental effect on the optical properties of the films. The effects of ion source gas species, ion energy and exposure time were studied systematically, and optimum conditions were derived to provide maximum film property enhancement. This study has demonstrated the potential to enhance coatings via the incorporation of an ion source for pre-treatment of glass within a standard production system.