Patent ID: 8127570

Claim:
A process for producing an optical element, which comprises producing an optical element blank and grinding and polishing said optical element blank, said optical element blank being formed of an optical glass comprising, by mass %, 5 to 32% of total of SiO 2 and B 2 O 3 , 30 to 60% of La 2 O 3 , 51 to 65% of total of La 2 O 3 , Gd 2 O 3 and Y 2 O 3 , 0.5 to 10% of ZnO, 1 to 20% of total of TiO 2 and Nb 2 O 5 , 0 to 15% of ZrO 2 , 0 to 2% of WO 3 , 0 to 20% of Yb 2 O 3 , 0 to 10% of total of Li 2 O, Na 2 O and K 2 O, 0 to 10% of total of MgO, CaO, SrO and BaO, 0 to 12% of Ta 2 O 5 , 0 to 5% of GeO 2 , 0 to 10% of Bi 2 O 3 , and 0 to 10% of Al 2 O 3 , 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 0.3 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 35/65, 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.