Multilayer high reflectance coating on polyethylene terephthalate film consisting of Ag/SiO2/TiO2 layers that are not quarter-wave thickness

Abstract

A multilayer high reflectance coating consisting of Ag, SiO 2 , and TiO 2 with R vis of 99.3% was successfully designed by simulation based on Maxwell's equations. The authors found that providing the low refractive index SiO 2 layer with non-quarter-wave thickness ͑0.14 of nd / for 550 nm light͒ near the Ag layer made a leading contribution to this high reflectance. They successfully made a multilayer high reflectance coating of Ag/ SiO 2 / TiO 2 on polyethylene telephthalate film with R vis of 99.4% based on that simulation. A backlight unit with a coating of Ag/ SiO 2 / TiO 2 exhibited high luminance 1.04 times that of Ag alone. Ag atoms are mixed with Si atoms upon deposit of a SiO 2 layer on Ag in an atmosphere with O 2 . A SiO 2 -P layer deposited under O 2 free conditions from a SiO 2 ceramic target and a TiO x layer deposited from Ti work well for protection of the Ag layer from oxidation upon deposit of SiO 2 .