| 摘要 |
PURPOSE:To obtain optical glass having a prescribed range of optical constant value, e.g. high refractive index and low dispersion and being safe for the human body and easy to produce in a technical scale by compounding specified com ponents. CONSTITUTION:20-50% (by weight) B2O3, 10-55% La2O3, 5-50% Yb2O3, 6-25% Al2O3, 0-10% SiO2, 0-3% R2O (a combination of >=1 kinds among Li2O, Na2O and K2O), 0-20% ZnO, 0-25% RO (a combination of >=1 kinds among MgO, CaO, SrO and BaO), 0-25% Y2O3, 0-10% ZrO2, 0-25% Ta2O5, 0-20% Nb2O5, 0-20% PbO, 0-10% WO2, 0-10% TiO2, 0-10% GeO2, 0-10% Gd2O3 and 0-5% F(substituted amt. for 0 when the whole shall be 100%) are compounded and vitrified to obtain the optical glass having the optical constant value within the range enclosed by the following six points, e.g. points, e.g. point A, B, C, D, E and F as shown in the figure (nd: refractive index, nud: Abbe number).
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