| abstract |
In an optical glass containing bismuth oxide, an optical glass having good processability is provided. In a measuring method according to “JOGIS09-1975 Measuring method of Knoop hardness of optical glass” containing Bi 2 O 3 in a mass% of 10% or more and less than 90%, a Knoop from grade 7 to grade 3 is used. It is an optical glass having hardness. Furthermore, the mechanical strength is adjusted by combining a predetermined amount of SiO 2 , B 2 O 3 and Rn 2 O components (Rn represents one or more selected from the group consisting of K, Na and Li). Can do. [Selection figure] None |