Method of manufacturing a glass substrate

PROBLEM TO BE SOLVED: To provide a method for producing a glass substrate where the glass substrate having a small thermal shrinkage factor is produced directly by a down-draw method. SOLUTION: The method for producing the glass substrate comprises a shaping step to shape molten glass to a glass ribbon by the down-draw method, an annealing step to anneal the glass ribbon and a cutting step to cut the glass ribbon and obtain the glass substrate after the annealing step. In the annealing step, the glass ribbon is cooled so that the average cooling rate of the glass ribbon in a temperature range from the annealing point of the glass ribbon to the annealing point of the glass ribbon minus 50°C is satisfied with a following equation denoted as log 10 R≤0.00018361Ta 2 -0.23414Ta+75.29 (wherein, R is the average cooling rate of the glass ribbon (°C/min); and Ta is the annealing point of the glass ribbon (°C)). COPYRIGHT: (C)2011,JPO&INPIT