Ion plating of durable optical coatings on plastics

Silicon oxide and titanium oxide films have been ion plated onto polyester and polyethersulphone substrates held at room temperature. The ion plating was carried out in argon and oxygen discharges at various radio frequency induced substrate biasing voltages. The refractive index, absorption coefficient and mechanical properties of the films were evaluated and their dependence on substrate biasing voltage determined. The ion plating technique gives films of moderate refractive indices, but excellent abrasion resistance was obtained with increasing r.f. bias voltages. (author)