Optical glass, precision press molding preform, and optical element and method of manufacturing the same

Optical glass, which is oxide glass comprising, denoted as cation %,

• a total of 5 to 60% of B3+ and with 5 to 50% of B3+,
• a total of equal to or higher than 5% of Zn2+ and Mg2+,
• a total of 10 to 50% of La3+, Gd3+, Y3+, and Yb3+, and
• a total of 6 to 45% of Ti4+, Nb5+, Ta5+, W6+, and Bi3+, with a total content of Ti4+ and Ta5+ being higher than 0% and a content of W6+ being higher than 5%;
• wherein 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 a content of Ta5+ to a total content of Ti4+ and Ta5+, Ta5+/(Ti4++Ta5+), is equal to or higher than 0.23;
• a cation ratio of a content of W6+ to a total content of Nb5+ and W6+, W6+/(Nb5++W6+), is equal to or higher than 0.30;
• a cation ratio of a total content of Ti4+, Nb5+, Ta5+, W6+, and B3+ to a total content of B3+ and Si4+, (Ti4++Nb5++Ta5++W6++B3+)/(B3++Si4+), is higher than 0.37 but equal to or lower than 3.00;
• a cation ratio of a total content of Zn2+, Mg2+, and Li+ to a total content of La3+, Gd3+, Y3+, and Yb3+, (Zn2++Mg2++Li+)/(La3++Gd3++Y3++Yb3+), is equal to or higher than 0.40;
• and
• which has a refractive index nd ranging from 1.90 to 2.00 and an Abbé number νd satisfying the following equation (1):
• 25≦νd<(3.91−nd)/0.06 (1).