| 摘要 |
PROBLEM TO BE SOLVED: To provide optical glass which does not contain a Pb compound and an As compound, has optical constants of a high refractive index and low dispersion and has a small specific gravity. SOLUTION: Glass components, by weight %, of 6 to 18% (not inclusive of 18%) SiO2, 13 to 35% B2O3, 16 to 25% (not inclusive of 16 and 25%) La2O3, 4 to 15% (not inclusive of 4%) TiO2, 20 to 35% CaO and <=3% (inclusive of zero) Li2O are incorporated into the optical glass. The further inclusion of one or >=2 kinds of the glass components of <=7% SrO, <5% BaO, <=5% ZnO, <=15% ZrO2, <=3% K2O and <=5% Bi2O3 into the optical glass in addition to the glass components described above is equally good in terms of meltability, devitrification resistance, chemical durability, etc.
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