PRODUCTION OF GLASS MATERIAL FOR MOLDING OPTICAL ELEMENT

摘要

PURPOSE:To produce a glass material of a desired shape free from defects on the surface and the interior of glass without a grinding and an polishing processes in producing a glass material of a reheating pressing material of high-precision optical glass element such as lens or prism. CONSTITUTION:In a method for producing a glass material by catching molten glass 1 falling from a glass outlet 10 of a glass melting furnace by a receiving mold 11 and cooling, the distance between the receiving mold 11 and the glass outlet 10 is set so as to be a distance wherein the molten glass 1 dropped in the receiving mold 11 is naturally cut by its empty weight and surface tension 4 and the temperature of the falling glass in the vicinity 3 of the cutting part is in a range of >= the softening temperature to produce the glass material. Since the glass flow in the vicinity of the cut part of the glass dropped in the receiving mold is instantly dropped at a temp. no lower than the softening temperature in glass on the receiving mold, difference in temperature will not occur without causing defects on the surface and in the interior of the glass.