METHOD FOR FORMING GLASS OPTICAL ELEMENT

摘要

PROBLEM TO BE SOLVED: To provide a method for forming a glass optical element capable of improving shape transferability and a parting property and drastically shortening the cycle time required for press forming. SOLUTION: This method for forming the glass optical element comprises press forming the thermally softened glass blank to be formed by the forming die consisting of a preheated upper die 35 and lower die 34. The temp. for heating the glass blank and the temp. for preheating the upper die 35 and the lower die 34 are set within prescribed ranges. The temp. for preheating the upper die 35 is set lower than the temp. for preheating the lower die 34. The thermally softened glass blank is then initially pressurized within the preheated forming die. The part near the forming surfaces of the upper die 35 and the lower die 34 are thereafter cooled simultaneously with or during or after the end of the initial pressurization. The pressure of the forming die is released and the glass molding is parted from the forming die after the temp. near the forming surfaces of the upper die 35 and the lower die 34 attains the prescribed temp. or below.