OPTICAL GLASS, OPTICAL ELEMENT AND PREFORM

摘要

PROBLEM TO BE SOLVED: To provide an optical glass capable of reducing a breakage or a crack of a glass at a press molding and enhancing productivity of an optical element while having a desired high refraction index and an Abbe number, and to provide a preform and an optical element using the same.SOLUTION: An optical glass contains Pand Alas a cation component and Oand Fas an anion component, and has a refraction index (nd) of 1.50 or more, the maximum value of a linear expansion coefficient (α) in a temperature range between a glass transition point (Tg) and a yield point (At) of 1500×10Kor less.