| 摘要 |
The lead- and arsenic-free optical glass has a refractive index nd of 1.55≦̸nd≦̸1.64, an Abbe number &ngr;d of 42≦̸&ngr;d≦̸65, and a low transition temperature Tg≦̸460° C., good producibility and processability, and crystallization stability. The optical glass has a composition within the following range, in wt. % based on oxide content: P2O5 40-58 ZnO 20-34 Li2O 0.5-5   GeO2 0.1-11. The glass may also have a total content of SiO2, B2O3 and Al2O3 that is less than 9 wt. %. The glass may contain MgO, SrO, CaO and BaO, but the sum of these oxides is preferably at least 2 wt. % and at most 12 wt. %. The glass may contain at most 5 wt. % of each of La2O3, TiO2, Nb2O5, at most 2 wt. % Ta2O5 and less than 1 wt. % fluorine.
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