Patent ID: 8003556

Claim:
An optical glass comprising: SiO 2 in an amount of more than 1.0% by mass and less than 12.0% by mass on the basis of an oxide, B 2 O 3 in an amount of 8.0 to 24.96% by mass, the ratio of SiO 2 /B 2 O 3 in terms of % by mass being more than 0 and less than 0.6, and La 2 O 3 in an amount of 25.0 to 50.0% by mass, and Y 2 O 3 in an amount of not more than 5.0% by mass, Yb 2 O 3 in an amount of 0.0 to 1.0% by mass, wherein the product of α and β where α is an average linear expansion coefficient within −30° C. to +70° C. and β is an optical elasticity constant at the wavelength of 546.1 nm is not more than 130×10 −12 ° C. −1 ×nm×cm −1 ×Pa −1 .