| 摘要 |
PROBLEM TO BE SOLVED: To provide highly refractive glass for a press-formed lens, which is free from components harmful to the human body, such as PbO or TeO<SB>2</SB>and expensive components such as GeO<SB>2</SB>, exhibits little deterioration in a spectral transmittance in the short wavelength side, has a high refractive index and a low melting point, and is excellent in mass productivity. SOLUTION: The optical glass for the press-formed lens has a composition comprising, by weight, 0-5% SiO<SB>2</SB>, 20-27% B<SB>2</SB>O<SB>3</SB>, 2-10% Ta<SB>2</SB>O<SB>5</SB>, 0.5-2% Li<SB>2</SB>O, 20-32% ZnO, 20-32% La<SB>2</SB>O<SB>3</SB>, 2-6% ZrO<SB>2</SB>, and 2-10% Nb<SB>2</SB>O<SB>5</SB>, with the proviso that the total amount of Ta<SB>2</SB>O<SB>5</SB>and Nb<SB>2</SB>O<SB>5</SB>is 10-20%, and has a refractive index of≥1.78 and a glass transition temperature of≤550°C. COPYRIGHT: (C)2005,JPO&NCIPI
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