| 摘要 |
<p>In manufacturing a glass substrate according to this process, a fused glass is formed into a sheet glass by an overflow process using a forming member in an upper space in a forming furnace, and then the sheet glass is made to flow from the upper space to a lower space wherein both edges of the sheet glass are cooled. The upper space is separated from the lower space by a heat-insulating member. The heat-insulating member has heat-insulating properties such that: when the fused glass is passing the forming member, the temperature of the fused glass can be controlled to the liquidus temperature or higher, while when the fused glass is passing the lowermost part of the forming member, the viscosities of both edges of the fused glass can be controlled to 104.3 to 106dPa·sec; and when the temperature of the central part of the sheet glass in the lower space is within a temperature range between a temperature higher than the softening point and a temperature in the vicinity of the annealing point, the viscosities of both edges of the sheet glass can be controlled to 109.0 to 1014.5dPa·sec.</p> |
