Patent ID: 7563736

Claim:
An optical glass consisting essentially of, as represented by mol %, from 25 to 70% of B 2 O 3 , from 5 to 30% of La 2 O 3 , from 5 to 25% of ZnO, from 1 to 20% of Ga 2 O 3 , from 0 to 15% of Li 2 O, from 0 to 20% of GeO 2 , from 0 to 10% of Y 2 O 3 , from 0.1 to 20% of TeO 2 , and from 0 to 20% of ZrO 2 +In 2 O 3 +Gd 2 O 3 +Ta 2 O 5 , wherein B 2 O 3 +GeO 2 is from 30 to 70 mol %, and the optical glass has an internal transmittance to a light having a wavelength of 400 nm of at least 90% as calculated in a thickness of 1 mm.