Optical lenses and processes of manufacture

摘要

PCT No. PCT/FR96/01486 Sec. 371 Date Nov. 6, 1997 Sec. 102(e) Date Nov. 6, 1997 PCT Filed Sep. 24, 1996 PCT Pub. No. WO97/11918 PCT Pub. Date Apr. 3, 1997The invention relates to lenses such as aspherical lenses and to a process for their manufacture. According to the invention, the lens is composed of a glass matrix including the constituents below in the following weight proportions: - SiO2 65-85% - Al2O3 0-10% - B2O3 0-20% - Li2O + Na2O + K2O 3-20% - CaO + MgO + BaO 1-15% - FeO + Fe2O3 0-0.1%, - wherein the K2O content is equal to or less than 1% and the BaO content is equal to or less than 1%.