Abstract: Provided is an optical glass including, by mass %, 33 to 60% of a content rate of SiO2, 10 to 35% of a content rate of TiO2, and 15 to 40% of a content rate of Na2O, wherein a refractive index nd with respect to a d-line is 1.71 or less.

Abstract: The present disclosure provides an optical glass including, by mass %, 27 to 41% of a P2O5 component, 7 to 17% of a Na2O component, 5 to 10% of a K2O component, 8 to 26% of a TiO2 component, and 5 to 39% of a Nb2O5 component, wherein a partial dispersion ratio (Pg,F) is equal to or less than 0.635.

Abstract: Provided is an optical glass including, by mass %, 24.5% to 41% of a P2O5 component, 6% to 17% of an Na2O component, 5% to 15% of a K2O component, over 0% to 7% or less of an Al2O3 component, 8% to 21% of a TiO2 component, and 5% to 38% of an Nb2O5 content, and the optical glass has a partial dispersion ratio (Pg, F) of 0.634 or less.

Abstract: Provide is an optical glass including: by mass %, 0% to 5% of a SiO2 component; 10% to 40% of a P2O5 component; 4% to 30% of a B2O3 component; 0% to 11% of a Na2O component; 5% to 20% of a K2O component; 0% to 20% of a TiO2 component; 0% to 2% of a ZrO2 component; and 20% to 70% of a Nb2O5 component, wherein P2O5 component+B2O3 component is more than 25% and 41% or less, B2O3 component/P2O5 component is 0.15 or more and less than 1.23, TiO2 component/P2O5 component is 0 or more and less than 1.3, and Nb2O5 component/P2O5 component is from 0.7 to 2.8.

Abstract: An optical glass that has a refractive index (nd) of 1.56-1.66, an Abbe number (vd) of 52-63, and a transformation temperature of 420° C.-580° C., as provided by compositions including as essential components (a) SiO2, (b) B2O3, (c) BaO, (d) Y2O3, (e) Li2O, and (f) one or more from CaO, MgO, SrO, and ZnO, and optionally one or more components from (g) Na2O, (h) K2O, (i) Al2O3, and (j) ZrO2.

Abstract: There is provided an optical glass that (1) has a high refractive index and high dispersion, (2) does not include any Pb compound that will tend to adversely impact the environment or human bodies, (3) is excellent in terms of economic efficiency, and (4) is suitable for mass production. This optical glass contains SiO2, B2O3, BaO, La2O3, TiO2, and, as necessary, one or more from Nb2O5, Ta2O5, WO3, ZrO2, MgO, CaO, SrO, ZnO, Li2O, Na2O, K2O, Y2O3, Gd2O3, and Al2O3—each in an amount within a predetermined range. This optical glass also has optical constant values such as a refractive index (nd) of 1.70-1.93 and an Abbe number (vd) of 28-45.