| 摘要 |
PURPOSE:To provide very slightly colored optical glass having an optical constant in a high refraction low dispersion region and stable spectrotransmittance by introducing SnO2 into B2O3-SiO2-La2O3-Yb2O3 type glass. CONSTITUTION:The optical glass consists of, by wt., B2O3+SiO2; 24-47%, SnO2; 0.05-4%, La2O3+Yb2O3+Gd2O3+Y2O3; 43-68%, Al2O3; 0-3%, GeO2; 0-5 %, ZrO2; 0-10%, Ta2O3; 0-8%, Nb2O3; 0-3%, MgO+ CaO+SrO+BaO +ZnO; 0-10%, one or more out of Li2O, Na2O and K2O in total; 0-0.5%, fluorides af F in total substituted for part or all of one or more kinds of the above oxides; 0-8% and As2O3 and/or Sb2O3; 0-0.2%.
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