Patent ID: 8431504

Claim:
An optical glass that is an oxide glass and comprises, by cationic %, 20 to 40% of a total of Si 4+ and B 3+ , 15 to 40% of a total of Nb 5+ , Ti 4+ , W 6+ and Zr 4+ , 0.2 to 20% of a total of Zn 2+ , Ba 2+ , Sr 2+ and Ca 2+ , and 15 to 55% of a total of Li + , Na + and K + , the cationic ratio of the content of B 3+ to the total content of B 3+ and Si 4+ being 0.01-0.5, the cationic ratio of the content of Zr 4+ to the total content of Nb 5+ , Ti 4+ , W 6+ and Zr 4+ being 0.05 or less, the cationic ratio of the content of Nb 5+ to the total content of Nb 5+ and T 4+ , (Nb 5+ /(Nb 5+ +Ti 4+ )), is 0.65-1, the molar ratio of the total content of Zn 2+ and Ba 2+ to the total content of Zn 2+ , Ba 2+ , Sr 2+ and Ca 2+ being 0.8-1, the optical glass having a refractive index nd of 1.815 or more and an Abbe's number vd of 29 or less.