| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide optical glass having high transparency with respect to a visible region, hardly generating devitrification or cloudiness in manufacture or processing of glass, and allowing easy manufacturing of a preform material or an optical element by polishing, and to provide a preform using the optical glass. <P>SOLUTION: This optical glass includes, in terms of mass% to the whole mass of glass having a composition in terms of oxides, a ≥70.0% to ≤90.0% Bi<SB POS="POST">2</SB>O<SB POS="POST">3</SB>component, a ≥6.0% to ≤20.0% B<SB POS="POST">2</SB>O<SB POS="POST">3</SB>component, and a >0% to ≤20% SiO<SB POS="POST">2</SB>component, respectively. <P>COPYRIGHT: (C)2013,JPO&INPIT |
