| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide high-refractive index and low-dispersion optical glass which is stably supplied, has excellent glass stability and exhibits little coloration. <P>SOLUTION: The optical glass is characterized by including, in mass, 5-32% of the total of SiO<SB POS="POST">2</SB>and B<SB POS="POST">2</SB>O<SB POS="POST">3</SB>, 45-65% of the total of La<SB POS="POST">2</SB>O<SB POS="POST">3</SB>, Gd<SB POS="POST">2</SB>O<SB POS="POST">3</SB>and Y<SB POS="POST">2</SB>O<SB POS="POST">3</SB>, 0.5-10% of ZnO, 1-20% of the total of TiO<SB POS="POST">2</SB>and Nb<SB POS="POST">2</SB>O<SB POS="POST">5</SB>, 0-15% of ZrO<SB POS="POST">2</SB>, 0-12% of Ta<SB POS="POST">2</SB>O<SB POS="POST">5</SB>and 0-5% of GeO<SB POS="POST">2</SB>(wherein, the mass ratio (SiO<SB POS="POST">2</SB>/B<SB POS="POST">2</SB>O<SB POS="POST">3</SB>) of the content of SiO<SB POS="POST">2</SB>to the content of B<SB POS="POST">2</SB>O<SB POS="POST">3</SB>is 0.3-1.0; the mass ratio (Gd<SB POS="POST">2</SB>O<SB POS="POST">3</SB>+Y<SB POS="POST">2</SB>O<SB POS="POST">3</SB>)/(La<SB POS="POST">2</SB>O<SB POS="POST">3</SB>+Gd<SB POS="POST">2</SB>O<SB POS="POST">3</SB>+Y<SB POS="POST">2</SB>O<SB POS="POST">3</SB>) of the total content of Gd<SB POS="POST">2</SB>O<SB POS="POST">3</SB>and Y<SB POS="POST">2</SB>O<SB POS="POST">3</SB>to the total content of La<SB POS="POST">2</SB>O<SB POS="POST">3</SB>, Gd<SB POS="POST">2</SB>O<SB POS="POST">3</SB>and Y<SB POS="POST">2</SB>O<SB POS="POST">3</SB>is 0.05-0.6; the refractive index nd is 1.90-2.0; the Abbe number νd is 32-38; and the degree of coloration λ70 is 430 nm or less). <P>COPYRIGHT: (C)2013,JPO&INPIT |
