LIGHT-TRANSMITTING OPTICAL-FUNCTION GLASS PART PREFORM AND PRODUCTION THEREOF

摘要

PURPOSE:To obtain a preform for light-transmitting optical function glass part and provide a process for producing the preform capable of slowly cooling the product to the room temperature without causing the breakage and cracking even in a core-clad combination having large expansion coefficient difference. CONSTITUTION:This process for the production of an optical part preform comprises the 1st step to successively cast molten liquids for forming a clad and a core into molds to form a core-clad structure and the 2nd step to cast a clad-forming molten liquid again into the mold to effect the fusion of the molten liquid with the clad glass cast in the 1st step and seal the core glass 6 with the clad glass 5.