Patent ID: 8338320

Claim:
An optical Glass characterized by comprising, denoted as molar percentages: B 2 O 3 5 to 45 percent; SiO 2 0 to 6 percent (excluding 6 percent); Li 2 O, Na 2 O, K 2 O in total 0 to 3 percent; ZnO 10 to 40 percent; La 2 O 3 5 to 30 percent; Gd 2 O 3 1 to 20 percent; and ZrO 2 , TaO 2 , TiO 2 , Nb 2 O 5 , 12.5 to 20 percent; WO 3 , and Bi 2 O 3 in total ZrO 2 , TaO 2 , TiO 2 , Nb 2 O 5 , WO 3 , and Bi 2 O 3 in total 12.5 to 20 percent; in that the cation ratio of the Ti 4+ content relative to the total content of Zr 4+ , Ta 5+ , Ti 4+ , Nb 5+ , W 6+ , and Bi 3+ is 0.30 or lower; in that the temperature Tp at which a viscosity of 10 7.2 dPa·s is exhibited is 706° C. or lower; and in that the refractive index nd and the Abbé number v(nu)d satisfy all of relations (I) to (IV) below 34.0≦vd<40 (I) nd≧1.87 (II) nd≧ 2.245−0.01 ×vd (III) nd≦ 2.28−0.01 ×vd (IV).