The preform production device and the optical component production device for the optical component, preform production manner and optical component production mannered null melting

摘要

PROBLEM TO BE SOLVED: To provide a heating apparatus which satisfactorily controls the occurrence of striae and the lowering optical properties and reduces the workload on maintenance.;SOLUTION: The heating apparatus 10 is used for heating a passage 90 through which molten glass flows and equipped with an inner wall 21 which forms an entry hole 29 allowing the tip 91 of the passage 90 to enter, heating parts 30 to heat the inner wall 21 and a high radiation part 40 made of a high emissivity material. The high radiation part 40 is separatedly located around the tip 91 of the passage 90 and underneath it, when the heating apparatus 10 is in operation.;COPYRIGHT: (C)2009,JPO&INPIT