| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide optical glass which has a high refractive index and low dispersion property and provides a preform for press molding that is excellent in high temperature moldability and suitable for precision press molding. <P>SOLUTION: The optical glass contains, as essential components, B<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>and ZnO, is substantially free from lead and fluorine, and has a refractive index of 1.72-1.83, an Abbe's number of 45-55, a glass transition temperature of≤630°C, and viscosity at a liquid-phase temperature of≥0.6 Pa s. Further, the optical glass contains, by mol, 45-65% of B<SB POS="POST">2</SB>O<SB POS="POST">3</SB>, 5-22% of La<SB POS="POST">2</SB>O<SB POS="POST">3</SB>, 1-20% of Gd<SB POS="POST">2</SB>O<SB POS="POST">3</SB>(wherein, the total content of La<SB POS="POST">2</SB>O<SB POS="POST">3</SB>and Gd<SB POS="POST">2</SB>O<SB POS="POST">3</SB>is 14-30%), 5-30% of ZnO, 0-10% of SiO<SB POS="POST">2</SB>, 0-6.5% of ZrO<SB POS="POST">2</SB>and 0-1% of Sb<SB POS="POST">2</SB>O<SB POS="POST">3</SB>, is substantially free from lead and fluorine, and has a refractive index of 1.72-1.83 and an Abbe's number of 45-55. <P>COPYRIGHT: (C)2013,JPO&INPIT</p> |
