| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical glass which is easy to perform press forming while a refractive index (n<SB POS="POST">d</SB>) and Abbe number (ν<SB POS="POST">d</SB>) are within the requested range, and can obtain a preform material with high devitrification resistance, and to provide a preform material and an optical element. <P>SOLUTION: The optical glass, based on the all glass substance amount of an oxide conversion composition, in mol%, includes: 10.0-50.0% of B<SB POS="POST">2</SB>O<SB POS="POST">3</SB>component; 5.0-30.0% of La<SB POS="POST">2</SB>O<SB POS="POST">3</SB>component; and at least 3.5% and at most 20.0% of Li<SB POS="POST">2</SB>O component. The preform material comprises the optical glass. Moreover, the optical element makes the optical glass a preform. <P>COPYRIGHT: (C)2012,JPO&INPIT |
