Glass with progressive change in colour obtd. by metal oxide film - and producing continuous variation in coefft. of light transmission in vertical direction, esp. for lenses in sunglasses

摘要

The graded colour is obtd. by evapn. of an organometallic cpd. such as a metal acetyl-acetonate which forms an oxide film on the glass. The pref. organometallic cpd. is the powdered acetyl-acetonate of divalent or trivalent Co; and the pref. glass is a continuous strip of curved lenses which is subsequently cut to form individual lenses for sunglasses. Graded colour is pref. obtd. by evapn. of layer of organo-metallic cpd. with graded thickness, or by using a screen to shield part of the glass strip; and/or the strip may be heated in a non-uniform manner to obtain the graded colour. Used esp. in mfg. lenses for sunglasses and providing improvements w.r.t. FR 2344505.