Highly refractive optical glass for spectacle lens - contains oxide(s) of silicon, boron, aluminium, lithium, sodium, potassium, calcium, barium, lead, zirconium and rare earth metals

摘要

Highly refractive, low dispersive optical glass has a refractive index ne of at least 1.79, an Abbe number Ve of at least 35, a density d of at most 4.5g. cm-3, a linear thermal coefft. of expansion alpha 20-300 of 7.7.10 power (-6) k-1, to 8.7.10 power (-6). K-1 and a compsn. in wt. % based on oxide, of 4-13.9 Si02; 7.26 B203; 0-4 Al203; 0-2 Li20; 0-2 Na20; 0-4 K20; 0.1-4 sigma R20; 1-12 CaO; 0-9 BaO; 5-15 PbO; 2-10 Zr02; 15-40 La203; 0-3 Bi203; 0.1-3 Y203; 3-7.9 Nb205; 0-15 Ta205; and 0-0.5 sigma As203+Sb203. USE - Glass is useful as spectacle glass for unifocal- and polyfocal-correction spectacles.