| 摘要 |
This specification discloses optical light-weight glass having a composition of SiO2 47-70, Li2O 5.5-21, K2O 2-30, Na2O 0-30 (Li2O+Na2O+K2O 21-50), TiO2 9.5-24, B2O3 0-20, CaO 0-20, MgO+SrO+BaO+ZnO 0-4, Al2O3 0-5 and ZrO2+La2O3+Ta2O5+WO3 0-3, all being in % by weight, and having a refractive index (nd) of 1.58-1.65, an Abbe number ( gamma d) of 35-50 and a specific gravity of 2.69 or less. This optical glass is light in weight, high in transparency and low in dispersion, and is particularly suitable for spectacle lenses, but can also be utilized for photographic lenses.
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