| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent the occurrence of shrink marks without requiring a reheat press, to obtain a substrate having good parallelism and to suppress the deterioration with lapse of time by use of press molds by spirally dropping molten glass press formed by the upper and lower molds onto the lower mold. SOLUTION: At the time of starting the dropping of the molten glass 3, the lower mold 2 rotates toward an arrow K within the horizontal plane around the center of the press plane. On the other hand, a nozzle 1 for dropping the molten glass 3 exists on the center of the lower mold 2 but the position of the nozzle 1 is fixed and, therefore, the position where the molten glass 3 is dropped is fixed. Next, when the lower mold 2 is kept rotated and is uniaxially moved in the radiol direction M of the lower mold 2 concurrently with the start of dropping of the molten glass 3, the molten glass 3 is dropped over the entire part of the press plane of the lower mold 2 while drawing spirals. When the dropping position of the molten glass 3, arrives at the prescribed outer peripheral part of the lower mold 2, the molten glass 3 is cut by a shear 5 and the spiral molten glass 4 is formed.</p> |
