| 摘要 |
An optical glass is oxide glass wherein Si4++B3+ ranges from 10-60 cation %, La3++Gd3++Y3++Yb3+ ranges from 25-70 cation %, Ti4++Nb5++W6++Bi3+ ranges from 10-20 cation %, Li+ content ranges from 0-5.0 cation %, Ge content is lower than 5.0 mass % as quantity of GeO2 based on oxides, no Pb included, a cation ratio, Si4+/B3+, is equal or lower than 0.70, a cation ratio, (La3++Gd3++Y3++Yb3+)/(Ti4++Nb5++W6++Bi3+), ranges from 1.90-7.00, a cation ratio, Y3+/(La3++Gd3++Y3++Yb3+), is equal or lower than 0.180, and Nb5+ is an essential component, with Ti4+/Nb5+ being equal or lower than 4.00, with nd of higher than 1.920 and equal or lower than 2.000, vd ranging from 28.0-34.0, and yield point higher than 645° C., and a deviation ΔPg,F from normal line of partial dispersion ratio Pg,F being equal or lower than 0.0005. |
| 主权项 |
1. Optical glass, which is oxide glass wherein:
a total content of Si4+ and B3+ ranges from 10 to 60 cation %; a total content of La3+, Gd3+, Y3+, and Yb3+ ranges from 25 to 70 cation %; a total content of Ti4+, Nb5+, W6 and Bi3+ ranges from 10 to 20 cation %; a content of Li+ ranges from 0 to 5.0 cation %; a content of Ge is lower than 5.0 mass % as a quantity of GeO2 in a glass composition based on oxides; no Pb is comprised; a cation ratio of a content of Si4+ to a content of B3+, Si4/B3+, is equal to or lower than 0.70; a cation ratio of the total content of La3+, Gd3+, Y3+, and Yb3+ to the total content of Ti4+, Nb5+, W6+, and Bi3+, (La3++Gd3++Y3++Yb3+)/(Ti4++Nb5++W6++Bi3+), ranges from 1.90 to 7.00; a cation ratio of a content of Y3+ to the total content La3+, Gd3+, Y3+, and Yb3+, Y3+/(La3++Gd3++Y3++Yb3+), is equal to or lower than 0.180; and Nb5+ is comprised as an essential component, with a cation ratio of a content of Ti4+ to a content of Nb5+, Ti4+/Nb5+, being equal to or lower than 4.00; which has a refractive index nd within a range of higher than 1.920 and equal to or lower than 2.000, an Abbé number vd ranging from 28.0 to 34.0, and a yield point of higher than 645° C.; and wherein a deviation ΔPg,F from a normal line of a partial dispersion ratio Pg,F obtained from the following equation is equal to or lower than 0.0005:
ΔPg,F=Pg,F+(0.0018×vd)−0.6483 wherein, in the equation, Pg,F denotes a partial dispersion ratio given by (ng−nF)/(nF−nC) using various refractive indexes ng, nF, and nC at spectral lines g, F, and c; and vd denotes the Abbé number. |
