Patent ID: 9604872
Date: 2017-03-28
CPC Classifications: C03B,C03C,Y02P

Claim:
1. An optical glass production method comprising carrying out a procedure to increase a water content in a molten glass during a melting step (i) of a glass raw material including at least one of TiO 2 , Nb 2 O 5 , WO 3 and Bi 2 O 3 in a melting container to thereby obtain the molten glass, wherein the optical glass has a total content of TiO 2 , Nb 2 O 5 , WO 3 and Bi 2 O 3 of 20 mol % or more and a P 2 O 5 content of 7 to 40 mol %, and the optical glass satisfies at least one selected from a group consisting of the following (a), (b), (c) and (d): (a) a total amount of P (b) a glass transition temperature Tg is 541° C. or more, (c) a content of Nb (d) a content of TiO