| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical glass which suppresses depletion of a mold in mold press forming while ensuring properties of a high refractive index and high dispersion, and enables an optical element having a smooth and uniform curved surface to be obtained, and to provide a preform and an optical element using the optical glass. <P>SOLUTION: The optical glass contains, by mass% with respect to the total mass of the composition based oxides, 50.0-80.0% of a Bi<SB POS="POST">2</SB>O<SB POS="POST">3</SB>component and 5.0-30.0% of a B<SB POS="POST">2</SB>O<SB POS="POST">3</SB>component, and has a refractive index (nd) of ≥1.90 and a viscosity at the liquidus temperature of ≥0.25 Pa s. The preform and the optical element comprise this optical glass. <P>COPYRIGHT: (C)2013,JPO&INPIT |
