Patent ID: 7659222

Claim:
An optical glass comprising SiO 2 , where the amount of SiO 2 is 2-9 mass %, B 2 O 3 , La 2 O 3 , Nb 2 O 5 and Ta 2 O 5 , where the Nb 2 O 5 and Ta 2 O 5 are essential components and where the total amount of Ta 2 O 5 +Nb 2 O 5 is 18-24 mass %, said optical glass having a refractive index of 1.83 or over and an Abbe number of 35 or over and being free of F, said optical glass further comprising Li 2 O in an amount of 0.5 mass % or over and having a glass transition temperature (Tg) of 670° or below.