Patent ID: 8883664

Claim:
Optical glass, which is oxide glass comprising, denoted as cation percentages: Si 4+ 0 to 30%; B 3+ 15 to 60%; Li + 0 to 10%; Na + 0 to 10%; K + 0 to 15%; Mg 2+ 0 to 20%; Ca 2+ 0 to 15%; Sr 2+ 0 to 20%; Ba 2+ 0 to 20%; Zn 2+ 13 to 40%; La 3+ 0 to 11%; Gd 3+ 0 to 10%; Y 3+ 0 to 6%; Yb 3+ 0 to 6%; Zr 4+ 0 to 5%; Ti 4+ 0 to 7%; Nb 5+ 2 to 20%; Ta 5+ 0 to 5%; W 6+ 0 to 10%; Te 4+ 0 to 5%; Ge 4+ 0 to 5%; Bi 3+ 0 to 5%; and Al 3+ 0 to 5%; wherein a combined content of Si 4+ and B 3+ ranges from 35 to 65%; a cation ratio of a content of B 3+ to the combined content of Si 4+ and B 3+ , B 3+ /(Si 4+ +B 3+ ), ranges from 0.3 to 1; a combined content of Li + , Na + , and K + ranges from 0 to 20%; a cation ratio of a content of Zn 2+ to a combined content of Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ , and Zn 2+ , Zn 2+ /(Mg 2+ +Ca 2+ Sr 2+ +Ba 2+ +Zn 2+ ), ranges from 0.30 to 1; a combined content of La 3+ , Gd 3+ , and Y 3+ ranges from 0 to 20%; a combined content of Ti 4+ , Nb 5+ , Ta 5+ , and W 6+ ranges from 10 to 20%; a cation ratio of the content of Ti 4+ to the combined content of Ti 4+ and Nb 5+ (Ti 4+ /(Ti 4+ +Nb 5+ )) ranges from 0 to 0.20; and a cation ratio of the combined content of Ti 4+ and W 6+ to the combined content of Ti 4+ , Nb 5+ , Ta 5+ , and W 6+ ((Ti 4+ +W 6+ )/(Ti 4+ +Nb 5+ +Ta 5+ +W 6+ )) ranges from 0 to 0.20, and comprising no Pb, with a refractive index nd ranging from 1.750 to 1.850, an Abbé number νd ranging from 29.0 to 40.0, and a glass transition temperature of less than 630° C.