| 摘要 |
PROBLEM TO BE SOLVED: To obtain an optical glass with less coloring even when a large amount of a high refractive index component is included.SOLUTION: The optical glass has a refractive index nd of 1.97 or more, has a total content of TiO, NbO, WOand BiOwithin the range from 40 mol% to 80 mol%, and shows a &bgr;OH value defined by formula (1):&bgr;OH=-ln(B/A)/t, of 0.1 mmor more. A glass raw material for press molding and an optical element using the optical glass are also provided. In formula (1), t represents the thickness (mm) of the optical glass used for the measurement of an external transmittance; A represents an external transmittance (%) at a wavelength of 2500 nm when the light is incident parallel to the thickness direction of the optical glass; B represents an external transmittance (%) at a wavelength of 2900 nm when the light is incident parallel to the thickness direction of the optical glass; and ln is a natural logarithm. |
