| 摘要 |
PURPOSE:To produce in high yield a large-sized glass plate from a columnar rod, by making opposing faces of a columnar rod of high-purity quartz glass flat, putting the rod in a graphite container and heating it in an inert gas atmosphere under pressure. CONSTITUTION:Columnar high-purity quartz glass having the diameter d0 is made from SiCl4 as a raw material, two opposing faces are cut and processed into flat faces and d/d0 is made into 0.9-0.99 when d is the width of the processed faces. The flat face of the quartz rod is placed on the bottom of the graphite container 2 and 3 and the graphite weight 4 is placed on the flat face and the glass rod is pressed while heating it in an inert gas atmosphere such as Ar, N2, etc., at 1,600-1,800 deg.C by a graphite resistant furnace or an induction furnace. Since the bottom of the quartz glass rod 1 is flat, it is not rotated and rolled into a plate state, rolled in such a way that a ratio of the diameter of the glass rod and the length l2 of the short side of the glass plate after the molding of d0/l2 is about 0.1-0.6 and production of large-sized quartz glass plate is made possible. |
