Patent ID: 8726696

Claim:
A method of manufacturing a glass substrate, comprising: a melting step melting a glass starting material and obtaining molten glass; a stirring step for stirring, inside a stirring vessel, the molten glass obtained in the melting step; and a molding step for molding a glass substrate from the molten glass stirred in the stirring step; wherein in the method of manufacturing a glass substrate, the stirring vessel is provided with a chamber for directing the molten glass downward from above, or upwardly from below, and a stirrer for stirring the molten glass inside the chamber; the stirrer has a shaft serving as a rotation axis disposed along the vertical direction, and blades disposed on a side face of the shaft, in a plurality of tiers from an uppermost tier to a lowermost tier along the axial direction of the shaft; the blades have support plates extending orthogonally to the axial direction of the shaft, and ancillary plates disposed on a principal face of the support plates; and in the stirring step, the stirrer rotates about the shaft as the rotation axis, whereby the ancillary plates create in the molten glass a flow in the radial direction of the shaft, and ancillary plates positioned between support plates of blades disposed in two adjacent tiers create, in the molten glass, a flow in the same direction, in the stirring step, at least one of the ancillary plates creates in the molten glass, along the support plate, a flow from the inner wall of the chamber towards the shaft, and at least one of the ancillary plates creates in the molten glass, along the support plate, a flow from the shaft towards the inner wall of the chamber.