Composition for forming silica-based coating with a low refractive index

Abstract

Compositions for forming silica-based coatings are provided that can form lower refractive-index layers of protective films on lenses of solid image-pickup devices or on optical members such as light guides. The compositions comprise a siloxane polymer and an alkyl quaternary amine. Such siloxane polymers are preferably utilized as hydrolysis products and/or partial condensates of at least one silane compound expressed by the formula (1) below: RnSiX4-n   (1) in which each R represents independently a hydrogen atom or a monovalent organic group, X represents a hydrolyzable group, n is an integer of 0 to 2, and plural Rs may be identical or different from each other.

Dependencies are inferred from the claim text.