Patent ID: 11236010

Abstract:
To provide an optical glass having the optical characteristics of a high refractive index and low dispersion, and moreover, which makes it possible to further reduce devitrification and which can be stably obtained, and a preform and an optical element using the same. The optical glass comprises, expressed in cation % (mol %), 17.0% to 42.0% of P5+, 7.0% to 30.0% of Al3+, more than 0% to 22.0% of Mg2+, more than 0% to 25.0% Ca2+, more than 0% to 30.0% of Sr2+, more than 0% to 35.0% Ba2+, and expressed in anion % (mol %), a content ratio of F− of 37.0 to 64.0%, a content ratio of O2− of 36.0 to 63.0%, a refractive index (nd) of 1.48 to 1.58, and having an Abbe number (vd) of 70 to 88, and a liquidus temperature of 800° C. or less.