| 摘要 |
PURPOSE:Optical thin and light glass useful for preparing lens of glasses having high refractive index, low specific gravity, high Abbe's number, consisting of a metal oxide having a specific composition. CONSTITUTION:Optical glass consisting of 56-67wt% SiO2, 0-7wt% B2O3, 0-5wt% Al2O3, 0-11wt% Na2O, 0-15wt% K2O, 0-7wt% Li2O (with the proviso that Na2O+K2O+Li2O is 11-18wt%), 12-19wt% TiO2, 0-4wt% MgO+ CaO+SrO+ZnO, and 0-2wt% La2O3+ZrO2+Nb2O3, having >=1.59 refractive index, >=36 Abbe's number, and <=2.6 specific gravity. Though it has low specific gravity, it has high refractive index, chromatic aberration at the periphery of lens can be reduced by providing it with high Abbe's number, so this glass is extremely useful as a material for lens of glasses.
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