Optical glass

A glass for precision press molding having a refractive index (nd) within a range from 1.825 to 1.870, an Abbe number (νd) within a range from 22 to less than 27, a transformation temperature (Tg) within a range from 530° C. to 585° C. and a mean coefficient of linear thermal expansion (α) within a range from 80×10−7° C.−1 to 100×10−7° C.−1, comprising SiO2, TiO2, Nb2O5 and Li2O and being substantially free of a Pb compound, wherein

• the SiO2 has a mass % that ranges from 18% to 36% calculated on oxide basis, the Nb2O5 has another mass % that ranges from greater than 42% to 55% calculated on oxide basis, and a ratio of Nb2O5/TiO2 is 2.7 or higher.

A glass for precision press molding having a refractive index (nd) within a range from 1.825 to 1.870, an Abbe number (νd) within a range from 22 to less than 27, a transformation temperature (Tg) within a range from 530° C. to 585° C. and a value of the formula −1:E·α/(1−ν) (where E represents Young's modulus, αis the mean coefficient of linear thermal expansion and νis Poisson's ratio) within a range from 1.00×106 Pa·° C.−1 to 1.35×106 Pa·° C.−1,comprising SiO2, TiO2, Nb2O5 and Li2O and being substantially free of a Pb compound, wherein

• the SiO2 has a mass % that ranges from 18% to 36% calculated on oxide basis, the Nb2O5 has another mass % that ranges from greater than 42% to 55% calculated on oxide basis, and a ratio of Nb2O5/TiO2 is 2.7 or higher.

A glass for precision press molding having a refractive index (nd) within a range from 1.825 to 1.870, an Abbe number (νd) within a range from 22 to less than 27, a transformation temperature (Tg) within a range from 530° C. to 585° C., a mean coefficient of linear thermal expansion (α) within a range from 80×10−7° C.1 to 103×10−7° C.−1 and a value of the formula −1:E·α/(1−ν) within a range from, 1.00×106 Pa·° C.−1 to 1.35×106 Pa·° C.−1, being substantially free of a Pb compound, and comprising SiO2, TiO2, Nb2O5 and Li2O, wherein

• the SiO2 has a mass % that ranges from 18% to 36% calculated on oxide basis, the Nb2O5 has another mass % that ranges from greater than 42% to 55% calculated on oxide basis, and a ratio of Nb2O5/TiO2 is 2.7 or higher.

A glass for precision press molding having a refractive index (nd) within a range from 1.825 to 1.870, an Abbe number (ν) within a range from 22 to less than 27, a transformation temperature (Tg) within a range from 530° C. to 585° C., a mean coefficient of linear thermal expansion (α) within a range from 80×10−7° C.−1 to 100×10−7° C.−1 and a value of the formula −1:E·α/(1−ν) (where E represents Young's modulus, a mean coefficient of linear thermal expansion and ν Poisson's ratio) within a range from 1.00×106 Pa·° C.−1 to 1.35×106 Pa·° C.−1, being substantially free of a Pb compound, and comprising SiO2, TiO2, Nb2O5 and Li2O, wherein

• the SiO2 has a mass % that ranges from 18% to 36% calculated on oxide basis, the Nb2O5 has another mass % that ranges from greater than 42% to 55% calculated on oxide basis, and a ratio of Nb2O5/TiO2 is 2.7 or higher.