Patent ID: 8656734

Claim:
A method for manufacturing multiple pieces of a disklike glass material, a sheet thickness of said pieces of disklike glass material varying within a range, comprising: preparing a glass melt by heating a starting material to melt while maintaining an Fe ion content in the starting material at a constant level so that an amount of variation in the Fe ion content in the glass melt be kept to within ±50 percent; the successive molding of multiple pieces of disklike glass material from the glass melt, wherein the Fe ion content in the disklike glass material ranges from 0.1 to 100 ppm and the molding of the glass melt into disklike glass materials comprises: controlling variation over time in the concentration of infrared radiation-absorbing ions contained in the glass melt being molded into said pieces of disklike glass material so that the variation in the sheet thickness of said multiple pieces of disklike glass material falls within a range of ±15 percent of a reference value, said reference value being the median between the maximum value and the minimum value of the sheet thickness of 1,000 pieces of said glass material, and press molding glass melt to obtain a disklike glass material.