A method for producing a glass preform, method of production manufacturing method and optical elements of glass molded body

摘要

PROBLEM TO BE SOLVED: To provide a glass preform lot comprising a plurality of spherical glass preforms which have each an average mass of ≤30 mg and the ratio of mass tolerance to the mass within ±0.3%, and also to provide a mass production method for the preform and a method for production of an optical element using the above preform.;SOLUTION: The method of producing the preform comprises drooping a molten glass flowing out of a nozzle 2 from the lower end thereof, dropping the drooping molten glass at a constant frequency in such a state that at least the circumference of the above drooping glass is covered by a cover 5 to obtain a molten glass drop, and forming the drop into the preform in a cooling process. The glass preform lot is composed of a plurality of the above preforms. The optical element is produced by heating the preform taken out from its lot and performing a precision press molding thereof.;COPYRIGHT: (C)2007,JPO&INPIT