| 摘要 |
PURPOSE:To enable production of the titled base material having a regulated shape and a large diameter by changing the flow rate of hydrogen supplied to a burner, the flow rate of silicon compd. and the angle of the burner for a starting member with the passage of time. CONSTITUTION:In a method synthesizing a porous quartz glass base material by accumulating a fine grain of silica which is produced by hydrolyzing a silicon compd. in the inside of oxyhydrogen flame on a rotating member, the shape of a produced porous quartz glass base material 11 is regulated by changing the flow rate of hydrogen supplied to a burner 5 for synthesis, the flow rate of silicon compd. and the angle of the burner 5 for the starting member 10 with the passage of time. An irregular shape part such as a recess is not formed in a bottom of the base material and the following base material can be produced with excellent reproducibility wherein the shape is regulated in the bottom, an outside peripheral part and the other part as a whole and the diameter is large. |
