| 摘要 |
An optical glass in which a Cr content is less than 5 ppm, or a Sm content is 3 ppm or less, with respect to a 100% basic glass composition containing 2-10% SiO2, 5-45% B2O3, 0-15% RO (R═Zn, Sr, Ca, Ba), 30-60% La2O3, 0-40% Ln2O3 (Ln=Y, Gd), and, 0-30% ZrO2+Nb2O5+Ta2O5 by weight, and an optical apparatus which is provided with an optical system having the optical glass.
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