| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical glass capable of reducing breakage or cracks of glass during press-forming while having a desired high refractive index (n) and a low Abbe number (ν), and thereby, capable of increasing productivity of an optical element, and to provide a preform and an optical element using the optical glass.SOLUTION: The optical glass comprises, expressed in terms of mass%, 50.0 to 90.0% of a BiOcomponent and 5.0 to 50.0% of a BOcomponent, and has a coefficient of linear expansion of 1600×10Kor less at the maximum (α). The preform and the optical element are made of the optical glass. |
