摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical glass having a small partial dispersion ratio (θg, F), while a refractive index and an Abbe number are in each desired range, and hardly generating clouding during cleaning and polishing of the glass, and to provide a preform and an optical element using the optical glass. <P>SOLUTION: This optical glass contains in mol%, a 10.0-60.0% SiO<SB POS="POST">2</SB>component and a >0% Ta<SB POS="POST">2</SB>O<SB POS="POST">5</SB>component with respect to the glass whole material amount having a composition in terms of oxides, and the chemical durability (water resistance) thereof by a powder method is in the class 1-3. <P>COPYRIGHT: (C)2013,JPO&INPIT |