Manufactured articles in silicon oxide and/or other mixed metallic oxides and process for their preparation in final or almost final dimensions

摘要

An optical article, which is a preform for an optical lens, which is isotropic, consisting essentially of silicon oxide or silicon oxide in combination with one or more oxides of elements belonging to Groups III to VI of the Periodic Table,the article having a dimensional precision which has tolerance to surface roughness and profilometric accuracy required in the spectral interval of 200-800 nm of the electromagnetic spectrum,the tolerance being between one-half and one-tenth wavelength corresponding to the range of about 0.350-0.02 mum.