| 摘要 |
PROBLEM TO BE SOLVED: To provide optical glass with sufficient acid resistance and weather resistance while satisfying optical characteristics. SOLUTION: This optical glass comprises, by mass, 42-60% SiO<SB>2</SB>, 2-10% B<SB>2</SB>O<SB>3</SB>, 0.5-11% CaO, 3-17% BaO, 0-10% SrO, 2-10% Li<SB>2</SB>O, 0-3% ZrO<SB>2</SB>and 0-2.5% La<SB>2</SB>O<SB>3</SB>, where total sum of Li<SB>2</SB>O, Na<SB>2</SB>O and K<SB>2</SB>O is 3-12%. Further, this optical glass has a refractive index of 1.55-1.60, an Abbe number of≥57, and an elution rate by an acid of <0.65 mass%, the transmittance of 500 nm wavelength light after treated at a high temperature and high humidity is≥80% at the thickness of 10 mm, and decrease of transmittance due to the treatment is≤10%. COPYRIGHT: (C)2006,JPO&NCIPI
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