| 摘要 |
PURPOSE:To prevent the generation of crackes in a lens in a cooling process after the press molding process of the lens by finishing the surfaces of molds at an excess glass material-relieving section disposed on the outer periphery of the molding surfaces in a surface precision enabling the smooth contraction movement of the molded lens material when cooled. CONSTITUTION:In a ring drum mold 4, a softened glass material 1 is put on a lower mold 3 and an upper mold 2 is subsequently moved downward to press the glass material 1. A lens having prescribed curved surfaces is thereby formed with the respective molding surfaces 2a and 3a of the upper and lower molds 2 and 3. In the mold for molding the lens, a relief section 5 for the excess 1a of the pressed glass material 1 is formed on the outer periphery of the molding surfaces 2a and 3a. A smooth surface processing is further applied to the upper and lower non-functional surface-processing surfaces 2b and 3b of the relief section 5. When the molded glass material 1 is cooled to wholly contract in the central direction of the mold, the excess 1a is smoothly moved from the relief section 5. Thereby, the generation of defects such as crackes in the molded lens is prevented in the cooling process. |
