Patent ID: 8741796

Claim:
An optical glass comprising, denoted by mass %, 5 to 12% of SiO 2 9 to 15% of B 2 O 3 , 32 to 55% of La 2 O 3 , 56.32 to 65% of total of La 2 O 3 , Gd 2 O 3 and Y 2 O 3 (comprising equal to or greater than 0.1% of Gd 2 O 3 ), 1 to 8% of ZnO, 1 to 20% of total of TiO 2 and Nb 2 O 5 (comprising equal to or greater than 0.1% of each of TiO 2 and Nb 2 O 5 ), 0.5 to 15% of ZrO 2 , 0 to 12% of Ta 2 O 5 , 0 to 5% of GeO 2 , wherein the mass ratio of the content of SiO 2 to the content of B 2 O 3 , (SiO 2 /B 2 O 3 ), is from 0.33 to 1.0, and the mass ratio of the total content of Gd 2 O 3 and Y 2 O 3 to the total content of La 2 O 3 , Gd 2 O 3 and Y 2 O 3 , (Gd 2 O 3 +Y 2 O 3 )/(La 2 O 3 +Gd 2 O 3 +Y 2 O 3 ), is from 0.05 to 0.6, the optical glass having a refractive index nd of 1.90 to 2.0 and an Abbe's number νd of 32 to 38 and having a coloring degree λ70 of 430 nm or less.