| 摘要 |
PROBLEM TO BE SOLVED: To obtain optical glass which softens readily at a low temperature even while a refractive index (n<SB>d</SB>) and an Abbe number (ν<SB>d</SB>) are within respective desired ranges, and substantially avoids devitrification and tinting in press molding, and a lens preform and an optical element using the same. SOLUTION: The optical glass contains an SiO<SB>2</SB>component, an Nb<SB>2</SB>O<SB>5</SB>component, a ZrO<SB>2</SB>component and an Li<SB>2</SB>O component as essential components, and has a refractive index (n<SB>d</SB>) of ≥1.78, an Abbe number (ν<SB>d</SB>) of ≤30 and a partial variance ratio (θg, F) of ≤0.620. The optical element uses the optical glass as a base material. COPYRIGHT: (C)2011,JPO&INPIT |
