Patent ID: 8034733

Claim:
An optical glass comprises, denoted as weight percentages: SiO 2 >10%->22% B 2 O 3 3.0%-24% ZnO >8.0% and <30% CaO + BaO + ZnO 10%-50% MgO 0-3% La 2 O 3 + Y 2 O 3 + Gd 2 O 3 + Yb 2 O 3 1.0-33% TiO 2 2.0-20% ZrO 2 0-10% Nb 2 O 5 2.0-32% Na 2 O 0-8% K 2 O 0-10% WO 3 2.0%-20%; CaO 0-4.4%; and ratio by weight of La 2 O 3 to combined contents of La 2 O 3 , Y 2 O 3 , Gd 2 O 3 , and Yb 2 O 3 (La 2 O 3 /(La 2 O 3 +Y 2 O 3 +Gd 2 O 3 +Yb 2 O 3 )) falls within a range of 0.8 to 1, wherein the optical glass contains no Pb and no Li 2 O, and wherein the glass exhibits a refractive index (nd) in a range of 1.80 to 1.95 and an Abbé number (v d ) in a range of 25 to 35.