| 摘要 |
PROBLEM TO BE SOLVED: To provide optical glass having high stability while maintaining precision press forming property, in a phosphate-based composition capable of realizing high optical characteristics high in utility value, such as high refractive index or high dispersibility. SOLUTION: The optical glass contains, as essential components, P<SB>2</SB>O<SB>5</SB>, SiO<SB>2</SB>and Li<SB>2</SB>O, and as arbitrary components, Na<SB>2</SB>O and K<SB>2</SB>O, wherein the molar ratio of Li<SB>2</SB>O/(Li<SB>2</SB>O+Na<SB>2</SB>O+K<SB>2</SB>O) is 1/3-1, Abbe number (νd) is≤30. Alternatively, the optical glass contains, as essential components, P<SB>2</SB>O<SB>5</SB>, SiO<SB>2</SB>and Li<SB>2</SB>O, and has such a transmittance characteristic that when incident light is made incident perpendicular to one of flat optical polished faces of a glass sample having a thickness of 10.0±0.1 mm and subjected to optical polishing, which surfaces are mutually parallel, a wavelength at which the transmittance expressed by the ratio (transmitted light intensity/incident light intensity) of the intensity of transmitted light launched from the other optical polished face after transmitting the glass sample to incident light intensity becomes 70% is not higher than 510 nm, and has a refractive index (nd) of≥1.8, an Abbe number (νd) of≤30, and a liquidus temperature of <1,000°C. COPYRIGHT: (C)2005,JPO&NCIPI
|
