| 摘要 |
PROBLEM TO BE SOLVED: To provide a high-dispersion optical glass that has a refractive index (nd) of 1.58-1.75, Abbe's number (νd) of about 30-47 with a small fluorescence by the ultraviolet excitation. SOLUTION: This low fluorescence optical glass comprises 9-17wt.% of B2 O3 , 13-29wt.% of P2 O5 , 8-22wt.% of R<1> 2 O (where R<1> 2 O is at least one selected from Li2 O, Na2 O and K2 O or a combination of 2 or more), 31-57wt.% of Ta2 O5 or Ta2 O5 +Nb2 O5 , 0-17wt.% of Nb2 O5 , 0-5wt.% of SiO2 , 0-13wt.% of R<2> O (where R<2> O is at least one selected from the group of MgO, CaO, SrO and BaO), 0-1wt.% of As2 O3 , and 0-1wt.% of Sb2 O3 with low fluorescence caused by ultraviolet excitation.
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