| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a preform for press molding of high quality without having radial surface striae, and to provide a manufacturing apparatus used for the method, and a method for manufacturing an optical element by precision press molding the preform. SOLUTION: The method for manufacturing the preform for press molding includes steps of discharging melted glass from a discharge pipe, separating a melted glass block, and molding the melted glass block into a preform on a molding die, and the method is characterized in that gas is blown to the melted glass block on the molding die from the upper side and/or obliquely from the upper side so as to cool the surface of the glass block exposed to the atmosphere. The manufacturing apparatus for the preform for press molding is equipped with a plurality of molding dies which receive melted glass blocks to mold into the preforms, a taking-out device to take out the preform from the die, and a conveying device to successively circulate and convey the molding dies. The apparatus is also equipped with a cooling gas injection mechanism to promote to cool the glass from the upper side and/or obliquely from the upper side of the melted glass on the molding die. COPYRIGHT: (C)2006,JPO&NCIPI
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